荧光成像技术在植物病害检测的应用研究进展

植物病害阻碍植物正常生长,对蔬菜产品品质安全造成威胁,病害检测可以有效控制植物病害发展,是提高果蔬品质安全和可持续生产能力的一个重要途径。所有的绿色植物在受到紫外光或可见光激发时,都会发出可见光波段的荧光。基于植物荧光的成像技术,是利用计算机模拟人眼的视觉功能,在不破坏植株外观且不影响其生长的情况下,获取植物的荧光图像,并通过图像处理算法,对植物的健康状况做出判断。本文对荧光成像技术及其在植物病害检测中的研究进行了综述,介绍了荧光成像的原理,分别从叶绿素荧光和其他色素荧光两方面总结了国内外研究现状。与可见光成像、高光谱成像、多光谱成像以及热成像技术相比,该技术具有可获取植物内部信息、受温湿度影响小、不局限于晴天采集、价格合理等优点。     

太赫兹波谱无损检测技术研究进展

太赫兹由于具有透视性、安全性和波谱分辨能力的特点,近年来得到了较快的发展和应用,成为无损检测的新技术,并被应用于国防、工业、半导体、通信、生物医学、制药、农产品及食品等多个领域.首先介绍了太赫兹波谱技术和成像技术的原理和特点,阐述了太赫兹技术在非金属材料特性和缺陷检测中的应用,并重点分析了近年来太赫兹技术在农产品及食品领域的应用新进展.最后,分析了太赫兹波谱无损检测技术的技术难点及问题,并对其发展趋势进行了展望.     

灰葡萄孢BC4菌株抑菌活性成分分离及对小麦纹枯菌的作用

首先探索了利用薄层色谱分离灰葡萄孢(Botrytis cinerea)BC4菌株抑菌活性代谢产物的溶剂系统,在此基础上分离得到了该菌4个代谢产物组分;然后以小麦纹枯菌为生物测定对象,观察了这4个组分对小麦纹枯菌菌丝生长的抑制活性;同时利用显微技术进一步观察了抑菌活性组分对小麦纹枯菌菌丝生长的影响部位。结果表明:在4种不同的薄层色谱溶剂系统中,石油醚+乙酸乙酯+甲酸(5∶4∶1)为分离灰葡萄孢BC4菌株抑菌活性代谢产物的较好展开剂。对利用该溶剂系统分离得到的4个代谢产物组分进行生物活性测定的结果表明,2个组分具有生物活性,其中组分4对小麦纹枯病菌有明显的抑制生长作用,相反组分2对其生长却有促进作用,组分1和3对该病菌没有作用。利用光学显微镜观察发现,接触组分4的小麦纹枯病菌菌丝顶端外部有深色液滴,对照则没有这种现象。利用扫描电镜观察的结果表明,接触组分4的菌丝与对照明显不同,菌丝停止向前延伸生长,分支增多,菌丝体出现不规则的膨大与缢缩,有些菌丝体新生部分变薄、模糊,有熔化迹象;有些与其它菌丝体粘合或融合在一起。表明灰葡萄孢BC4菌株代谢的抑菌活性成分对小麦纹枯菌的菌丝体体壁的形成具有严重阻碍作用,与三唑酮具有相似的作用特点。     

Agreement of Serum Spec cPL with the 1,2‐o‐Dilauryl‐Rac‐Glycero Glutaric Acid‐(6′‐methylresorufin) Ester (DGGR) Lipase Assay and with Pancreatic Ultrasonography in Dogs with Suspected Pancreatitis

Background

Spec cPL is the most sensitive and specific test for diagnosing pancreatitis in dogs. Its results have not been compared to those of the 1,2‐o‐dilauryl‐rac‐glycero‐3‐glutaric acid‐(6′‐methylresorufin) ester (DGGR) lipase assay or those of abdominal ultrasonography.

Objectives

To investigate agreement of Spec cPL with DGGR lipase activity and pancreatic ultrasonography in dogs with suspected pancreatitis.

Animals

One hundred and forty‐two dogs.

Methods

DGGR lipase activity (reference range, 24–108 U/L) and Spec cPL were measured using the same sample. The time interval between ultrasonography and lipase determinations was <24 hours. The agreement of the 2 lipase assays at different cutoffs and the agreement between pancreatic ultrasonography and the 2 tests were assessed using Cohen''s kappa coefficient (κ).

Results

DGGR lipase (>108, >216 U/L) and Spec cPL (>200 μg/L) had κ values of 0.79 (95% confidence interval [CI], 0.69–0.9) and 0.70 (CI, 0.58–0.82). DGGR lipase (>108, >216 U/L) and Spec cPL (>400 μg/L) had κ values of 0.55 (CI, 0.43–0.67) and κ of 0.80 (CI, 0.71–0.9). An ultrasonographic diagnosis of pancreatitis and DGGR lipase (>108, >216 U/L) had κ values of 0.29 (CI, 0.14–0.44) and 0.35 (CI, 0.18–0.52). Ultrasonographically diagnosed pancreatitis and Spec cPL (>200, >400 μg/L) had κ values of 0.25 (CI, 0.08–0.41) and 0.27 (CI, 0.09–0.45).

Conclusions and Clinical Importance

Although both lipase assays showed high agreement, agreement between ultrasonography and lipase assays results was only fair. Because lipase results are deemed more accurate, ultrasonography results should be interpreted carefully.     

Accuracy of a machine-vision pellet detection system

Video cameras are employed on net pen fish farms for monitoring food pellet levels near the cage bottom. Herein, the accuracy of a new machine-vision system for the identification of a feed-wastage event and its response time are reported. Research involved novel tests and definitions, video footage recorded under different stocking and environmental conditions, and numerical filters to reduce the effects of misclassifications and patchiness of the pellet wastage record on overall system accuracy. Single-frame food pellet detection accuracy was based on the difference between computer-generated and actual frame counts of pellets greater than 30 pixels in size. A pellet wastage event was defined as a median of three or more visible pellets per frame. During tests on still video frames from different feeding events, the system missed 0.1±0.1 to 1.3±0.4 pellets frame⁻¹, and miss-classified as pellets 0±0.1 to 2.3±0.5 objects frame⁻¹ (n=264). Most missed pellet images were on top of fish images. Waste matter accounted for 65% of the misclassifications, while particles associated with poor camera maintenance accounted for approximately 24%. The average response time to a pellet wastage event was 5.1 and 11.4 s for sampling rates of 2 frames s⁻¹ and 0.5 frames s⁻¹, respectively (n=20 different pellet wastage events). The longest response time (26 s) occurred when fish were amassed against the camera and/or covering pellets. Using appropriate camera lens, camera positioning and/or ‘warning’ software can address fish-interference problems.     

通道效应与学习者的个体差异性对多媒体学习效果的实验研究

在以往研究的基础上,通过教学实验来考察多媒体计算机教学环境下,不同呈现方式的视频教学录像片的学习者的个体差异性(只把学习者按照其医学知识经验水平的高低进行划分),以及通道效应是否显著。     

对林业投入的思考

林业投入不仅包括传统的资金投入、物资投入和劳动投入这３种实体形态的硬要素投入，还包括软要素投入，即林业体制投入（含政策、法规、管理投入）、林业科技投和（含教育、科技、信息投入）和林业监督投入（含管制奖惩投入）。长期以来，由于对林业投入的观念存在误区，片面强调林业投入中的资金、人力、物力的硬要素，忽视法规、科技、信息、管理等软要素的投入，严重制约了我国林业的发展。在我国转变林业经济增长方式，实施可持续发展的形势下，加强林业软要素投入，树立“大投入”的思想观念，对于我国林业发展有着十分重要的意义。     

油菜根肿病菌形态及生物学特性研究

油菜根肿病近年在四川省发生日趋严重。本文报道了油菜根肿病菌休眠孢子的显微形态结构,其在扫描电镜下休眠孢子近球形,孢壁不光滑,有乳状突起,直径为1.9~4.3μm(平均3.5μm);透射电镜下游动孢子近球形、肾形或椭圆形,直径为1.6~3.5μm(平均2.8μm),同侧着生不等长尾鞭式双鞭毛。观察了休眠孢子萌发形成游动孢子、休止孢、休止孢再萌发形成芽管的过程。病菌休眠孢子萌发的最适温度是24℃,最适pH值是6.3,腐烂处理促进休眠孢子萌发,光抑制休眠孢子萌发,休眠孢子在过滤灭菌的根分泌物中萌发率最高为62.50%。