黄鳍鲷肝细胞体外培养研究

以黄鳍鲷肝脏细胞为材料 ,研究其肝细胞体外培养适宜的 p H、血清浓度、谷氨酰胺等条件 ,并进行传代培养试验。结果表明 ,培养液为 :MEM含 2 0 %小牛血清、15 g/ L L-谷氨酰胺及 p H 6 .9～ 7.1时 ,在 2 3℃中静置培养 ,黄鳍鲷肝细胞生长良好 ,3～ 5 d长满单层 ,细胞主要为成纤维细胞状 ,并能顺利传代。细胞动力学试验表明 :传代细胞 1～ 2代为适应期 ,3～ 5代为旺盛期 ,6代之后表现出衰老现象     

农村电网中有源电力滤波器的研究

随着农村电网中电力电子装置的日益增多,农村电网中的谐波污染问题越来越严重.为此,简要分析了并联型有源电力滤波器的系统结构和工作原理;建立了采用DSP数字控制的适合于三相三线制的并联型有源电力滤波系统, 重点分析了该系统指令电流和PWM信号的产生、硬件结构与软件流程, 并通过实验验证了该系统可以有效地抑制农村电网谐波,改善农村电网电能质量.     

家兔黏膜免疫器官肥大细胞在巴氏杆菌感染中的特征——组织化学与电镜观察

对5例巴氏杆菌感染家兔的空肠与圆小囊肥大细胞（mast cell，MC）进行了组织化学与电镜的观察，发现在细菌感染导致的病变组织边缘、病变组织内血管附近结缔组织中及变性细胞周围组织的上皮下与黏膜下层都出现了大量甲苯胺蓝（Toluidine Blue，TB）阳性肥大细胞。电镜下，MC有的直接与变性细胞密切接触，有的则和血管内皮紧密相触，在此部位的血管内可见有淋巴细胞贴附填充。MC胞浆内充盈大量的特征性颗粒，有时这些颗粒向细胞表面突出形成边缘空隙，即形成所谓的脱颗粒管道，将颗粒内容物逐渐排除细胞外，遗留空腔。     

Wetland effects on lake water quality in the Minneapolis/St. Paul metropolitan area

A method developed to evaluate the cumulative effect of wetland mosaics on water quality was applied to 33 lake watersheds in the seven-county region surrounding Minneapolis-St. Paul, Minnesota. A geographic information system (GIS) was used to record and measure landscape variables derived from aerial photos. Twenty-seven watershed land-use and land-cover variables were reduced to eight principal components which described 85% of the variance among watersheds. Relationships between lake water quality variables and the first six principal components plus an index of lake mixis were analyzed through stepwise multiple regression analysis. A combination of three landscape components (wetland/watershed area, agriculture/wetlands, and forest/soils components) explained 49% of the variance in a trophic state index, even though most of the lakes examined were already highly eutrophic, and thus were influenced by internal loading. The regression equations explained a range of 14 to 76% of the variation in individual water quality variables. Forested land-use was associated with lower lake trophic state, chloride, and lead. High lake trophic state was associated with agricultural land-use and with wetland distance from the lake of interest. The extent of wetlands was associated with low total lead and high color in lakes downstream. Wet meadows or herbaceous, seasonally-flooded wetlands contributed more to lake water color than did cattail marshes.     

Resident Dendritic Cells in the Epidermis: Langerhans Cells, Merkel Cells and Melanocytes

Résumé— En plus des kératinocytes, l'épiderme contient des cellules résidentes de morphologie dendritique. Ce sont principalement la cellule de Langerhans, la cellule de Merkel et le mélanocyte. Ces cellules ont des fonctions diverses dans le tégument. Le mélanocyte assure la pigmentation cutanée et la protection contre les radiations U.V., et pourrait intervenir également dans la modulation de l'inflammation cutanée. La cellule de Langerhans intervient dans la surveillance immunologique des surfaces corporelles ecternes. La cellule de Merkel a des fonctions neuroendocrines. Cet article donne un aperçu de la structure et de la fonction de ces trois importantes populations cellulaires dans la peau. [Resident dentritic cells in the epidermis: Langerhans cells, Merkel cells and melanocytes (Cellules dentritiques résidentes de l'épiderme: cellules de Langerhans, cellules de Merkel et mélanocytes). Resumen— La epidermis contiene, además de los queratinocitos, células résidentes de morfologia dendria dendritica. Estas son principalmente las células de Langerhans, las células de Merkel y los melanocitos. Estas células tienen varias funciones en el integumento. Los melanocitos se encargan de la pigmentación y protección de la piel contra la radiación ultravioleta y tarrtbién participan en la regulación de la inflamación cutánea. Las células de Langerhans ayudan en la regulación inmunológica en la superficie externa. Las células de Merkel tienen funciones neuroendocrinas. Esta revisión da un repaso general a la estructura y función de tres importantes células de la piel. [Resident dendsuitic cells in the epidermis: Langerhans cells, Merkel cells and Melanocytes (Células résidentes en la epidermis: células de Langerhans, células de Merkel y melanocitos). Abstract— In addition to the keratinocytes, the epidermis contains resident cells of dendritic morphology. These are principally the Langerhans cell, Merkel cell and melanocyte. These cells have a number of different functions in the integument. The melanocyte is responsible for skin pigmentation and protection against UV radiation, and may also play a role in the modulation of cutaneous inflammation. The Langerhans cell aids in the immunological monitoring of the body's external surfaces. The Merkel cell has neuroendocrine functions. This review gives an overview of the structure and function of these three important cells of the skin.     

猪胚胎干细胞的分离克隆

本文从分化抑制物、培养基的选择内细胞团的分离,胚胎干细胞的分离及鉴定方法等方面系统地综述了猪胚胎干细胞分离克隆的研究进展;并对其未来的应用前景进行展望。     

哺乳动物体细胞克隆研究进展

哺乳动物体细胞克隆技术是近年来才发展起来的技术，但体细胞克隆绵羊－多利的诞生却引起了世界轰动，充分显示了其重在的科学研究价值和潜在的应用价值。本文对哺乳动物体细胞克隆技术研究现状，理论基础研究，应用等方面作一综述。     

Differences in Wheat Cultivar Response to N Supply. I: Differences in Grain Yield Formation

Two-year field trials with winter wheat cultivars Batis and Toronto were conducted in Southern Bavaria, Germany, to investigate the possible causes of cultivar differences in response to N supply varying in total amount and time of application. Cultivar-related differences in grain yields were observed in treatments with low and medium N supply. High doses of N supply resulted in grain yield adjustment or grain yield advantage for cv. Toronto. The results of this study revealed a consistent, genotypic pattern in response to N fertilization in spite of strong seasonal effects. Systematic modifications in canopy growth rates in response to N supply were of particular relevance and a main factor for differences in tillering intensity resulting in modified stand densities. In the present study, cultivar differences in spike development and interactions with N supply related more to abortion than to initiation processes for number of spikelets and number of flowers per spikelet. High grain density (grains per m²) of cv. Toronto was evident during reproduction stages even under conditions of medium N supply. However, decreased growth rates during the later part of grain filling in combination with low 1000 grain weight, which was barely modified by N fertilization, allowed only partial utilization of this potential. It is assumed that sink limitations were of particular relevance for grain yield development in cv. Toronto, while cv. Batis combined a less intense response to N supply with more stability in the development of grain yield components.     

沼液浸种增强早稻秧苗耐冷效应─—叶肉细胞超微结构动态观察

经沼液浸种的早稻秧苗比对照组秧苗，具有较强的耐冷性，通过电镜对叶肉细胞超微结构动态观察证实，在低温（５°／５℃）下，叶绿体结构和细胞核结构，随着冷害天数的延长，伤害在不断加重，叶绿体结构会出现空洞，基质片断裂，直至崩溃。细胞核染色体凝集，核膜破裂，核内容物丧失等现象出现。而经沼液浸种的秧苗伤害程度有较明显的减轻。     

华山松,赤松次生韧皮部的解剖学观察

华山松，赤松次生韧皮部轴向系统由筛胞、韧皮部薄壁细胞及径向片组成，径向系统为射线。径向片和射线中具有蛋白细胞，其特点是细胞核大，细胞质浓，与筛胞之间以单侧筛域相联系。在无功能韧皮部，筛胞和蛋白细胞死亡，被挤毁，射线细胞分裂扩张，并积累后含物。