太子参芜菁花叶病毒和蚕豆萎蔫病毒的双重RT-PCR检测

针对不同产地栽培的太子参(Pseudostellaria heterophylla)中主要存在芜菁花叶病毒(Turnip mosaic virus,Tu MV)和蚕豆萎蔫病毒(Broad bean wilt virus,BBWV)侵染且为害严重的情况,建立能同时检测这2种病毒的双重RT-PCR快速检测方法。根据Gen Bank数据库中的Tu MV、BBWV外壳蛋白(coat protein,CP)基因核苷酸序列的保守区域分别设计简并引物,在单一RT-PCR检测体系的基础上,建立和优化双重RT-PCR检测体系。双重RT-PCR的优化结果显示,最佳扩增循环数为35,最佳引物浓度为0.4μmol·L~(-1),最佳退火温度为51℃。其灵敏度测定结果显示,2种病毒在样品c DNA稀释至原液的10-4倍后仍能扩增出特异条带。应用该方法对7份栽培太子参样品和4份脱毒苗样品进行了检测,结果表明,建立的双重RT-PCR检测方法可稳定、准确、灵敏地同时检测Tu MV和BBWV。     

The effect of vaccination with the PAV-250 strain classical swine fever (CSF) virus on the airborne transmission of CSF virus

The airborne transmission of Classical Swine Fever (CSF) virus to susceptible pigs, as well as the effect of vaccination with the CSF virus PAV-250 strain was investigated on this mode of transmission. Experiment I: four pigs were inoculated with the ALD CSFV strain (10(4.3) 50% TCID) by the intramuscular route, and at the onset of fever, they were introduced into an enclosed chamber. At the end of the experiment surviving pigs were sedated, anesthetized and euthanatized. Experiment II: four pigs were previously vaccinated with the CSF virus PAV-250 strain, and at 14 days post-vaccination they were challenged with the CSF virus ALD strain. In both experiments, four susceptible pigs were exposed to infectious aerosols by placing them in a chamber connected by a duct to the adjacent pen containing the infected animals and were kept there for 86 hs. In Experiment I, pigs exposed to contaminated air died as a result of infection with CSF virus on days 14, 21 and 28 post-inhalation. These four pigs seroconverted from day 12 post-inhalation. CSF virus was isolated from these animals, and the fluorescent antibody test on tonsils was positive. In Experiment II, a vaccinated pig exposed to contaminated air did not seroconvert, nor was CSF virus isolated from lymphoid tissues. However, mild fluorescence in tonsil sections from these pigs was observed. In conclusion, CSF virus was shown to be transmitted by air at a distance of 1 m to susceptible pigs. Vaccination with the PAV-250 CSF virus strain protected the pigs from clinical disease under the same conditions.     

间伐对辽东山区长白落叶松人工林生境和更新的影响

为弄清间伐对落叶松人工林内环境因子,进而对落叶松林内天然更新的影响,在辽东山区对40年生落叶松人工林进行了5种不同强度的间伐试验(分别为0%、10%、20%、30%和40%)。间伐后,对环境因子和更新状况进行了观测。结果表明,林冠开阔度随间伐强度增大而增加,间伐后其林冠下光量子数量、地表平均温度、不同层次土壤平均含水量与空隙度大小成线形关系;落叶松人工林间伐一年内,更新树种丰富度没有显著变化,而更新密度和更新频度都明显增加(p<0.05)。更新树种数量增加与树种特性有关,增长幅度为阳性树种>耐荫树种。所有的更新树种中,对林冠开阔度变化响应最大的是黄波罗(Phellodendronamurense)。实验结果证实了辽东地区落叶松人工林间伐后,更新数量变化与周围保留的树种分布、树种特性和立地条件有关。图9表2参43。     

Development of LVL frame structures using glued metal plate joints II: strength properties and failure behavior under lateral loading

In past years high priority was given to developing a seismic design for wood structures, including research on the response of wood structures to earthquakes. In this study a new type of portal frame with relatively large span was developed for the traditional Japanese wooden houses with large openings at the front to strengthen the structure. Stainless steel plates coated with zinc and glued with epoxy adhesives on laminated veneer lumber (LVL) members, composed of Douglas fir veneer and bonded with phenolformaldehyde resin, were used. The connection between the frame's beam and columns and between the columns and groundsills was mechanical, with bolts. The subject of this research was to analyze strength properties and failure behavior of glued LVL metal joints used as structural components and to evaluate the response of LVL portal frames under cyclic lateral loading. The results show that portal frames using glued LVL metal plates have a good multiplier for the shear walls and may be applied to traditional Japanese structures. The equivalent viscous damping provided good energy dissipation in the frames. The joints displayed good mechanical behavior during tests; moreover, the structures demonstrated high strength, stiffness, and ductility, which are necessary for a seismic design.Part of this paper was presented at the 47th annual meeting of the Japan Wood Research Society, Kouchi, April 1997; and at the 5th world conference on timber engineering. Montreux, Switzerland, August 1998     

An unusual case of a mature teratoma on the left perineal region of a young cat: surgical treatment and pathological description

A 10-month-old intact male cat with a clinical history of a large mass in the left perineal region was submitted to the surgery department. The mass had reportedly been present as a small swelling after birth. Cytological evaluation using a fine-needle aspirate showed eosinophilic keratinaceous debris, and was not convincing for the definitive diagnosis. Complete surgical excision was performed. Postoperative function and aesthetics were excellent. Based on gross and histological features the definitive diagnosis of the tumor was mature teratoma with ectodermal and endodermal components. After a follow-up period of 4 months, no signs of recurrence were evident. Surgical excision of the teratoma in our case was considered curative. A perineal location has not been previously reported in the cat and should be considered a rare condition in this species.     

罗马尼亚不同沙棘品种叶中甘树脂的提取

沙棘（Hippophae rhamnoides）是一种可广泛生长于欧亚地区,包括罗马尼亚的小果实灌木。沙棘具有药用及营养价值,同时可以改善区域的微气候环境。人们已经研究了罗马尼亚沙棘的生物化学组分及相关数据,所以我们分析了不同沙棘叶的甘树脂,一个重要的生化参数可以为植株的一项基本新陈代谢——光合作用提供信息。结果表明根据品种及特定环境因素的不同,产生了多样性。     

Development of LVL frame structures using glued metal plate joints I: bond quality and joint performance of LVL-metal joints using epoxy resins

Bond quality and joint performance between laminated veneer lumber (LVL) and metal plates were investigated. Commercially fabricated LVL made of Douglas fir veneer and bonded with phenol-formaldehyde resin as well as three types of epoxy adhesives were used. Various surface preparations and treatments were applied to ordinary steel, stainless steel, and aluminum plates to remove the weak boundary layer that is incompatible with the resin and form a stable adherend layer that is chemically and mechanically compatible with the resin. Small specimens were tested in shear to search the most suitable metal surface for bonding with LVL. Generally, shear strength obtained for the specimens bonded with aluminum plates was lower than those bonded with ordinary steel plates. Among them chemically treated (ChT) and roughened (R) surfaces have demonstrated superior performance. To investigate strength performance and bond quality, LVL beams jointed with metal plates were tested while bending. The best results were obtained for specimens bonded with zinccoated metal plates, though good results were obtained also for ChT and R plates. However, the fracture proved to be fragile when no drift pins were used, even for high-performance surface treatments. The usage of drift pins was necessary to add toughness and avoid the brittle status of the fracture.