人工神经网络在中医诊断信息化中的应用          下载免费PDF全文

刘旺华  洪净  李花  孙贵香  陈燕 《勤云标准版测试》2017,37(7):809-812

中医学是一个非常复杂的系统,临床证候之间、临床证候与诊断目标之间、临床证候与方药之间的关系具有非线性、复杂性、模糊性、非定量的特点。人工神经网络能从海量数据中提取隐含的有意义的知识,能模拟这种非线性映射关系,建立诊断、判别模型,做出前瞻性决策,正是这种优势使得人工神经网络技术有可能为解决中医脉象辨识信息化、中医舌象辨识信息化、中医证候辨识信息化中权值难以明确的问题提供更为科学的方法与途径。  相似文献   

Multispecies Phytophthora disease patterns in declining beech stands     

Beat Ruffner  Daniel Rigling  Corine N. Schoebel 《Forest Pathology》2019,49(3)

Decline diseases are typically caused by complex abiotic and biotic interactions and characterized by a suite of symptoms indicative of low plant vigour. Diseased trees are frequently infected by Phytophthora, but the complex interactions between pathogen, host and the heterogeneous forest environment mask a comprehensive understanding of the aetiology. In the present study, we surveyed European beech (Fagus sylvatica) stands in Swiss forests with recent increases in bleeding lesions for the presence of Phytophthora. We used a combined approach of analysing soil and bark samples from trees displaying bleeding lesions and trees free from bleeding lesions. Soil baiting revealed a higher prevalence of Phytophthora spp. around trees with bleeding lesions than around trees without bleeding lesions. For the bark samples from bleeding lesions, we used several detection methods. Phytophthora spp. were detected in 74% of the trees by an immunological on‐site diagnostic kit, in 64% by a specific PCR assay, and 38% by isolation on selective media. All samples tested were negative for P. ramorum using qPCR. Overall, nine Phytophthora species were identified by ITS sequencing, the most common of which were P. plurivora, P. gonapodyides, P. × cambivora and P. syringae. We identified distinct species in bleeding lesions and the rhizosphere of the same host tree which suggests a multispecies Phytophthora disease patterns in these declining beech. Among the recovered species, P. × cambivora and P. × serendipita were identified as hybrid genotypes with the former abundant in bleeding lesions.  相似文献   

Development of a lateral flow device for in‐field detection and evaluation of PCR‐based diagnostic methods for Xanthomonas campestris pv. musacearum,the causal agent of banana xanthomonas wilt          下载免费PDF全文

J. Hodgetts  G. Karamura  G. Johnson  J. Hall  K. Perkins  F. Beed  V. Nakato  M. Grant  D. J. Studholme  N. Boonham  J. Smith 《Plant pathology》2015,64(3):559-567

Xanthomonas campestris pv. musacearum (Xcm) is the causal agent of banana xanthomonas wilt, a major threat to banana production in eastern and central Africa. The pathogen is present in very high levels within infected plants and can be transmitted by a broad range of mechanisms; therefore early specific detection is vital for effective disease management. In this study, a polyclonal antibody (pAb) was developed and deployed in a lateral flow device (LFD) format to allow rapid in‐field detection of Xcm. Published Xcm PCR assays were also independently assessed: only two assays gave specific amplification of Xcm, whilst others cross‐reacted with non‐target Xanthomonas species. Pure cultures of Xcm were used to immunize a rabbit, the IgG antibodies purified from the serum and the resulting polyclonal antibodies tested using ELISA and LFD. Testing against a wide range of bacterial species showed the pAb detected all strains of Xcm, representing isolates from seven countries and the known genetic diversity of Xcm. The pAb also detected the closely related Xanthomonas axonopodis pv. vasculorum (Xav), primarily a sugarcane pathogen. Detection was successful in both naturally and experimentally infected banana plants, and the LFD limit of detection was 10⁵ cells mL^?1. Whilst the pAb is not fully specific for Xcm, Xav has never been found in banana. Therefore the LFD can be used as a first‐line screening tool to detect Xcm in the field. Testing by LFD requires no equipment, can be performed by non‐scientists and is cost‐effective. Therefore this LFD provides a vital tool to aid in the management and control of Xcm.  相似文献   

A novel pair of universal primers for the detection of potyviruses     

L. Zheng  B. C. Rodoni  M. J. Gibbs  A. J. Gibbs 《Plant pathology》2010,59(2):211-220

A novel pair of universal primers was developed to detect potyvirus species after conserved sites were identified using all full‐length potyvirus sequences available by 2005. The breadth of specificity of the new primers, NIb2F and NIb3R, was investigated and compared with the specificity of two routinely used primer pairs in plant virus diagnostic laboratories. RNA from 40 potyvirus isolates representing 23 recognized and three possible new species was tested. Reactions with NIb2F and NIb3R produced amplicons of 350 bp from all 40 virus isolates tested. Reactions with the previously published WCIEN and Potyvirid primers amplified cDNA from 32 and 21 isolates, representing possibly 21 and 15 species, respectively. The identity of 12 unknown potyvirus isolates was confirmed by sequencing and three were found to be potentially distinct potyvirus species. Gel banding patterns from reactions with NIb2F and NIb3R were simpler to interpret than those from reactions with the other two primer sets; fewer products were visible and the cDNA fragments were less variable in size. RT‐PCR with the novel primers is predicted to be able to detect virus isolates from all major groups within the genus Potyvirus and its reliability makes it well suited for use as a routine diagnostic assay.  相似文献   

Species-specific detection of Bipolaris sorokiniana from wheat and barley tissues     

P. Matusinsky  P. Frei  R. Mikolasova  I. Svacinova  L. Tvaruzek  T. Spitzer 《Crop Protection》2010

Cochliobolus sativus (anamorph: Bipolaris sorokiniana) is a fungal pathogen that can cause yield limiting diseases of barley and wheat. A PCR-based diagnostic assay was developed to detect B. sorokiniana in barley and wheat tissues using the pathogen-specific primers COSA_F/R derived from the melanin biosynthesis pathway Brn1 locus. Specificity was tested against more than 30 fungal organisms associated with barley and wheat. Limit of detection was determined to be 0.001 ng for pure fungal DNA. The species-specific primers were capable of detecting the pathogen in planta, specifically from infected barley leaves and wheat roots and stem bases.  相似文献   

小反刍兽疫研究进展     

徐琼  何宇乾  吴海燕 《动物医学进展》2012,(8):93-96

小反刍兽疫(PPR)是由小反刍兽疫病毒(PPRV)引起的急性或亚急性传染病,为世界动物卫生组织(OIE)法定报告的动物疫病,易感动物以山羊、绵羊等小反刍动物为主。目前,小反刍兽疫主要流行于西非、中非、中东、阿拉伯半岛及南亚等地区。敏感特异的检测方法和高效的预防性疫苗将为该病的防控奠定良好的基础。论文对小反刍兽疫全球流行现状、诊断技术及疫苗研究进展进行了综述。  相似文献   

病例教学法在兽医临床诊断学教学中的探索与实践     

张淼涛  李勤凡  蒿彩菊  王妍  李蓉  董强 《畜牧兽医杂志》2019,(3):64-66

兽医临床诊断学是动物医学专业重要的专业基础课,具有很强的实践性。通过病例教学法的实施,有效的激发了学生学习兴趣,培养了学生临床思维的能力,提高了教学效果。本文结合兽医临床诊断学的特点,总结近年来的教学成果,介绍了病例教学法在课程教学中的意义、实施方法及注意事项等,以期进一步提高兽医临床诊断学的教学效果。  相似文献   

植物病害数值诊断概述(一)   总被引：2，自引：0，他引：2  

赵国防  陈德芬 《天津农业科学》1998,4(3):16-18

植物病害数值诊断法是运用模糊数学原理和灰色系统理论，将植物病害症状信息用隶属度或灰度进行量化为诊断指数，在诊断中用模糊识别，经简单加减运算求和，以和值最大者为诊断结果。此法具有简便易于掌握，快速诊断准确率高的特点，是植物病害诊断与模糊数学、灰色系统理论、信息论等新学科相结合的一种新方法。  相似文献   

Inoculum prevalence, host infection and biological control of Colletotrichum acutatum: causal agent of blueberry anthracnose in British Columbia   总被引：1，自引：1，他引：0  

N. Verma  L. MacDonald  Z. K. Punja 《Plant pathology》2006,55(3):442-450

To identify the causal organism of anthracnose (ripe-rot), which reduces yield and postharvest quality of blueberries grown in British Columbia, Canada, 80 isolates were recovered from diseased fruits collected from commercial blueberry fields during 2002–04 and identified as Colletotrichum acutatum using colony morphology, growth rate and species-specific PCR primers. In vitro incubation of replicated sets of inoculated detached berries at various temperatures produced infection at temperatures of 7–30°C, with an optimum at 20°C. Colletotrichum acutatum could not survive on the soil surface as mummified berries but the pathogen was detected mostly within flower buds and less so in blueberry twigs and fruit trusses. Infection of developing flower buds in May–June of the preceding growing season gave the highest inoculum recovery in the following year. Two commercial fungal biocontrol agents, Prestop ( Gliocladium catenulatum ) and PlantShield ( Trichoderma harzianum ), each reduced anthracnose development in 2003 and 2004 by up to 45% when sprayed three times onto plants between flowering and fruit ripening.  相似文献   

Use of next‐generation sequencing for the identification and characterization of Maize chlorotic mottle virus and Sugarcane mosaic virus causing maize lethal necrosis in Kenya     

I. P. Adams  D. W. Miano  Z. M. Kinyua  A. Wangai  E. Kimani  N. Phiri  R. Reeder  V. Harju  R. Glover  U. Hany  R. Souza‐Richards  P. Deb Nath  T. Nixon  A. Fox  A. Barnes  J. Smith  A. Skelton  R. Thwaites  R. Mumford  N. Boonham 《Plant pathology》2013,62(4):741-749

The diagnosis of novel unidentified viral plant diseases can be problematic, as the conventional methods such as real‐time PCR or ELISA may be too specific to a particular species or even strain of a virus, whilst alternatives such as electron microscopy (EM) or sap inoculation of indicator species do not usually give species level diagnosis. Next‐generation sequencing (NGS) offers an alternative solution where sequence is generated in a non‐specific fashion and identification is based on similarity searching against GenBank. The conventional and NGS techniques were applied to a damaging and apparently new disease of maize, which was first identified in Kenya in 2011. ELISA and TEM provided negative results, whilst inoculation of other cereal species identified the presence of an unidentified sap transmissible virus. RNA was purified from material showing symptoms and sequenced using a Roche 454 GS‐FLX+. Database searching of the resulting sequence identified the presence of Maize chlorotic mottle virus and Sugarcane mosaic virus, a combination previously reported to cause maize lethal necrosis disease. Over 90% of both viral genome sequences were obtained, allowing strain characterization and the development of specific real‐time PCR assays which were used to confirm the presence of the virus in material with symptoms from six different fields in two different regions of Kenya. The availability of these assays should aid the assessment of the disease and may be used for routine diagnosis. The work shows that next‐generation sequencing is a valuable investigational technique for rapidly identifying potential disease‐causing agents such as viruses.  相似文献