Studies on Antagonism between Exorchis ovariolobularis and Schistosoma japonicum in Oncomelania hupensis

目的　探讨在日本血吸虫中间宿主湖北钉螺体内叶巢外睾吸虫和日本血吸虫的对抗性。　方法　通过叶巢外睾吸虫和日本血吸虫对湖北钉螺的双重感染 ,计算血吸虫的感染率和尾蚴逸出量 ,常规石蜡切片观察钉螺组织学变化。　结果　钉螺在感染血吸虫 37d后再感染外睾吸虫 ,经一定时间后检查发现 ,血吸虫的感染率为 5 2 9% ,显著低于同时单独感染日本血吸虫对照组的感染率 (75 9% ) ;先感染叶巢外睾吸虫 ,经 10、 32、6 0、 10 0和 12 0d不同的时间间隔后再感染日本血吸虫的钉螺 ,血吸虫感染率分别为 6 4 %、 6 6 7%、 6 5 2 %、5 6 4 %和 5 7 1% ,而单独感染日本血吸虫对照组钉螺血吸虫感染率为 90 5 % ,经统计检验 ,各双重感染实验组血吸虫与对照组的感染率间差异具有显著或非常显著性意义 (P <0 0 5或P <0 0 1)。对各试验组及对照组钉螺逸出尾蚴试验发现 ,试验组钉螺血吸虫尾蚴逸出量均显著低于对照组的逸出量。组织学观察发现各双重感染组钉螺消化腺萎缩 ,消化腺盲囊间隙只有少量血吸虫子胞蚴 ,血吸虫子胞蚴皱缩、变形及不规则 ,且子胞蚴中只含稀疏的尾蚴胚球 ,有的子胞蚴中已无胚球 ;而单独感染血吸虫的对照组中血吸虫均发育到成熟的子胞蚴或尾蚴。　结论　钉螺体内叶巢外睾吸虫和日本血吸虫之间存Objective To examine the antagonistic interactions between Schistosoma japonicum and Exorchis ovariolobularis in the snail host, Oncomelania hupensis . Methods The infection rate and average number of cercariae of S japonicum were examined in O hupensis which had been superinfected with S japonicum and E ovariolobularis .The experimental snails were histologically observed by paraffin section. Results When snails were fed with eggs of E ovariolobularis 37 days later than S japonicum infection, the infection rate of S japonicum (52 9%) was significantly lower than that of the single S japonicum infected control (75 9%). When E ovariolobularis infected snails were exposed to S japonicum miracidia at different intervals, the infection rates of S japonicum were 64%, 66 7%, 65 2%, 56 4% and 57 1%, respectively. On the other hand, the infection rate of S japonicum in the single infected control was 90 5%. There existed significant differences. Furthermore, the average number of S japonicum cercariae shed from superinfected snails were significantly less than that of single S japonicum infected control. The histological observation showed that the larvae of S japonicum in superinfected snails were sluggish in development, irregular, shrunken, deformed, relatively small in number as compared with the control. The sporocysts contained few germ balls or immature cercariae and most of the digestive glands of superinfected snails were atrophied. Conclusion There is antagonism between E ovariolobularis and S japonicum in O hupensis , and E ovariolobularis is dominant in this situation

Using Feedback Random Framework to Improve the Hore Sensor Displacement Measurement Range

霍尔器件可用于微位移测量,但实用时要设计复杂的磁路以保证在测量范围内为均匀梯度磁场。通常只能测1MM左右的位移,这限制了其应用范围。采用反馈随动机构带动霍尔传感器跟踪被测体的位移,从而大大扩大了位移的测量范围,且不需要在测量中保持均匀梯度磁场。Hore unit can be used to microdisplacement measurement.But it is necessary to design a complex magnetic route to ensure the even grad magnetic field within measuring field.Usually it can only measure about 1 mm displacement,which deeply restrict its application.In this paper a feedback random framework is used to drive Hore sensor to track the displacement of the measured object.This framework greately enlarges the measure range and it can also work in non-even grade magnetic field.福建省科技项目资助(2007H0036

Comparison of four promoters for transient expression of RFP reporter gene in cultured Bombyx mori cells (Bm-e-HNU5)

以红色荧光蛋白基因(RFP)为报告基因,构建含4种不同启动子的重组表达质粒,用脂质体介导法转染家蚕Bombyxmori细胞(Bm-e-HNU5),观察家蚕细胞质肌动蛋白4基因启动子(A4)、α微管蛋白基因启动子(α-tub)、蚕丝心蛋白重链基因启动子(Fib)和家蚕核型多角体病毒早期即刻蛋白基因启动子(IE)4种启动子调控RFP报告基因在家蚕细胞内的瞬时表达情况。构建的重组表达质粒pDsRed-α-tub、pDsRed-A4、pDsRed-IE和pDsRed-Fib经双酶切和PCR鉴定正确无误。转染和转录实验结果表明,除了pDsRed-A4外,其他3种重组质粒在Bm-e-HNU5细胞中都得到高转染率,α-tub、IE和Fib可依次增强RFP报告基因在家蚕细胞内的瞬时表达活性。The red fluorescent protein reporter gene (RFP) was used to construct recombinant plasmids containing four different promoters, i. e., the cytoplasmic actin4 promoter (A4), α-tubulin promoter (α-tub)from silkworm, the Bombyx mori nuclear polyhedrosis virus immediate early protein promoter (IE) and the fibroin heavy chain gene promoter (Fib), respectively. These recombinant plasmids, i. e., pDsRed-A4,pDsRed-α-tub,pDsRed-Fib and pDsRed-IE, had been constructed successfully by restriction enzyme digestion and PCR analysis, and then were transfected into B. mori cell lines (Bm-e-HNU5) by lipid-mediated method to observe the ability of the four promoters to drive RFP reporter gene transient expression in cells. Transfection and transcription experiments indicated that except pDsRed-A4, the other three kinds of recombinant plasmids all transfected Bm-e-HNU5 obviously. The promoters of α-tub, IE and Fib enhanced the transient expression activity of RFP reporter gene in the Bm-e-HNU5, and their activity strengthened sequentially.国家自然科学基金项目(39870410

金属Cu表面三维齿状微图形的复制加工——约束刻蚀剂层技术 (CELT)的应用

主要介绍了一种Cu的CELT加工的化学刻蚀体系和捕捉体系 ,并通过控制刻蚀时间、刻蚀电流、刻蚀剂浓度、捕捉剂浓度等实验参数和优化电化学模板的制作工艺 ,以规整的齿状结构为模板 ,在Cu的表面实现了三维微结构的复制加工 ,得到了与齿状结构模板互补的三维微结构 ,用SEM和AFM对实验结果进行了表征 ,表征结果证明约束刻蚀剂层技术在金属三维加工方面的可行性和潜在优势。金属Cu由于具有优良的导热导电性能以及很好的延展性 ,在微系统 (也称微机电系统 )中应用广泛 ,因此对Cu的刻蚀加工对微系统技术的发展具有重要的意义。约束刻蚀剂层技术 (ConfinedEtch antLayerTechnique简称CELT)作为一种新型的微加工技术[1] ,能够加工复制出复杂三维结构 ,到目前为止 ,该技术已成功应用于Si、GaAs等材料微结构的复制加工[2 ,3]

OBSERVATIONS ON THELIFE CYCLE OF EXORCHIS OVARIOLOBULARIS AND ITS DEVEL OPMENT IN THE NATURAL MOLLUSCAN HOST

本文报告叶巢外睾吸虫 ( Exorchis ovariolobularis)幼虫期人工感染图氏窄口螺 ( Stenothyratoucheana) ,在其体中发育的全过程。从实验螺获得的本吸虫成熟尾蚴 ,在实验室内经实验小鱼获得囊蚴。用囊蚴感染阴性鲶鱼 ( Parasilurusasotus) ,获得本吸虫的童虫和成虫。由此证明图氏窄口螺是本吸虫的适宜的贝类宿主。叶巢外睾吸虫是寄生在闽江下游的鲶鱼肠道 ,闽江两岸河畔有大量图氏窄口螺孳生栖息 ,但没有钉螺。已故唐仲璋教授早年在福州闽江已发现鲶鱼肠中的外睾吸虫成虫及在图氏窄口螺体中的本吸虫尾蚴 ,绘有草图 ,并推测该尾蚴可能是外睾吸虫的幼虫期。本文实验证实了他的推断。证明图氏窄口螺是福建闽江鲶鱼的叶巢外睾吸虫的天然贝类宿主。该地区本吸虫天然流行的具体情况有待进一步调查Observations on the experimental infection of Exorchis ovariolobularis in Stenothyra toucheana and the whole life cycle of this trematode species were repsrted.The mature cercariae were obtained from the experimentally infected snails, and then were transformed into metacercariae in experimental fishes.The metacercariae were fed to negative Parasilurus asotus, and juveniles and adults could be obtained from P.asotus's intestine. This experiment demonstrated that S.toucheana is an appropriate molluscan host of this trematode species. E.ovariolobularis parasitizes the intestine of Parasilurus asotus of lower reaches of Min River. On the sides of lower reaches of Min River, There are many snails of S.toucheana which is the major species in that enviornment where no Oncomelania hupensis can be found.The late professor Tang C.C.had found adults of E.ovariolobularis in the intestine of Parasilurus asotus and cercaria of this species of tremotode in S.toucheana. He supposed that this cercaria should be the larval stage of E.ovariolobularis. This experiment confirmed his conjecture and demonstrated that S.toucheana is the natural molluscan host of E.ovariolobularis. The natural epidemiology of E.ovariolobularis needs further investigations

The histology, histochemistry and scanning electron microscopy study of Exorchis ovariolobularis rediae

运用组织学、组织化学及扫描电镜方法对叶巢外睾吸虫 ( Exorchis ovariolobularis)雷蚴进行了详细的观察 .叶巢外睾吸虫雷蚴具有完善的摄食器官及强的活动能力 ,其强大的肌质咽在早期雷蚴首先分化出来 .这是在钉螺媒介中叶巢外睾吸虫直接对抗血吸虫幼虫期的物质基础 .The biological characheristics of the rediae of Exorchis ovariolobularis have been studied in the way of histology, histochemistry and scanning electron microscopy. It was found that the Exorchis ovariolobularis rediae, which is equipped with a well developed mouth, a strong muscular pharynx is actively mobile. The structure of the rediae form the basis of redial direct antagonism against Schistisoma sporocyst

Foreign Competition,Industrial Linkage and Domestic Firms' Survival in China

大规模外资涌入不可避免地挤占了本土企业的生存空间。基于2000—2007年中国微观企业数据,本文首次采用生存模型考察了外资进入对中国本土企业的存活期限与退出行为的影响。研究表明,虽然外资企业加剧了行业内竞争,从而迫使同行业内资企业更快退出,但也通过与当地企业构建上、下游产业关联,为内资企业创造了新的存活机会与市场空间。这一作用也决定了外资进入对内资企业存活的竞争冲击并不如普遍预期的剧烈。与国有企业相比,民营企业更有可能与外资企业建立产业关联,从而较好地适应外资冲击。本研究不仅为客观评价外资进入的生存冲击提供了经验证据,也对东道国本土企业积极应对外资竞争、融入全球化分工网络具有借鉴意义。The influx of foreign investment inevitably forces China's domestic firms to exit,and hence decreases the survival probability of the latter.Using Chinese manufacturing firms' data during 2000—2007,we adopt the survival analysis to examine the effect of foreign entry on the survival of Chinese domestic firms.We find that although foreign firms do propel more domestic firms to exit among the same industry through the competition effect,they also help to promote the survival of the local firms through both backward and forward industrial linkages.As we estimate a significantly positive combined effect,it indicates the external shock due to foreign entry is not as big as we usually expect.Compared with SOEs,Chinese private firms are more likely to establish vertical industrial linkages with foreign-invested firms.Generally our findings provide evidence and policy suggestions on how local firms in developing economies adapt themselves to market competition due to foreign entry.教育部“新世纪优秀人才支持计划”(NCET-11-0248); 国家自然科学基金(71203107;71473136); 霍英东教育基金基础性研究课题(141083); 南开大学中央专项基金课题(NKZXB1226)的资

Advances in the research on silkworm microsatellite DNA.

概述了分子标记技术,就其中的微卫星标记技术的原理、方法与特点进行了介绍,重点就该技术在家蚕中的研究进展进行了综述,并展望了该技术在家蚕的遗传分析、辅助选择育种等应用中的前景。In this article,the molecular marker technology is outlined and the application principle,method and traits of microsatellite marker of silkworm are reviewed.Especially,we introduce the applications of the technology in the Bombyx mori in detail and the outlook of genetic analysis,marker-assisted selection and so on are prospected

research of process management of linux

1引言Linux作为一个多任务的操作系统,支持分时处理,由于其良好的性能,完善的设计,在服务器、台式机、嵌入实时等领域得到了广泛的应用.在操作系统的几个关键设计中,如内存管理、中断管理、进程、文件系统、进程通信等方面都有独到的特点,而作为操作系统的关键部分之一--进程管理方面,Linux作了较为周密的考虑,系统的高效、稳定很大一部分来自于进程管理的严整规划