Morphology and Microstructure of Spider Dragline Silk from Araneus Ventricosus

The spider dragline silk has excellent mechanical properties. The stress- strain curves of dragline silk fibers have intraspecific and intraindividual variability because of the spiders active control during spinning process. To investigate the relationship between the morphology of dragline silk fibers and spinning conditions, four samples were made at the reeling rates of 1mm/s, 20mm/s, 43.5mm/s and 110mm/s from the major ampullate glands of Araneus Ventricosus and the other two of dragline silks were prepared from a crawling or dropping spider. The surface microstructure and nanofibril characteristic were analyzed with atomic force microscopy (AFM). AFM images of 2000nm*2000nm and 500nm*500nm of these samples showed that the spinning condition influenced the surface roughness and fibril size, while AFM images of 200nm*200nm clearly displayed that dragline silk of Araneus Ventricosus included sheet macro-conformation structure. These results can facilitate the further investigation of the spinning mechanism of a spider in order to understand mechanical properties and macromolecular structures of dragline silk.     

浅谈地面测报管理经验

做好管理工作是做好地面测报工作的基础,随着气象业务现代化建设不断增强,高新技术不断引入气象领域,信息与网络技术的广泛应用,集约化和开放式业务日渐增多,办公自动化水平日益提高,原来的业务流程和运作模式已远远不能适应开放式的规范管理需要。本文对笔者多年测报工作中总结出来的一些业务管理经验进行了介绍。     

毛毛虫怎么过大河?

欲到达幸福、成功的彼岸,且看——一次相聚,有个同学出了一道关于想像力的题给大家:对岸鲜花盛开,四季如春,恍如天国,毛毛虫要去对岸生活,可是一条大河阻住了去路,桥又在很远的地方,那么毛毛虫要怎么样才能过大河?当时很纳闷,毛毛虫要怎样过大河呢,无非是长途跋涉,从桥上爬过去。可是同学们的答案却是千奇百怪,异想天开……一位刚出校门的女同学说:“游过去喽!”(天,是毛毛虫呀,不是人。)一位立志要做编辑的同学说:搭船过去!一位想从商的同学说:躲在别人身上过去!(哈,天才毛毛虫!)而那位想当律师的同学想了好久,才肯定地说:从地图上爬过去!…     

亚硝酸盐介导的降压效应及其机制探讨

以新西兰白兔为实验动物，观察外源性亚硝酸盐对动脉血压和血液气体的影响，以探讨亚硝酸盐对血管平滑肌舒缩和血液循环的效能.结果发现实验动物注射微量亚硝酸盐后，动脉血压迅速下降，1－3min后血压降到最低点（动脉血压降到最低点时间的长短与注入亚硝酸盐量呈负相关），血压下降幅度与所注入的亚硝酸盐量呈正相关。随着亚硝酸盐注入量的增加，实验兔血中高铁血红蛋白量略有上升，而氧分压、氧合血红蛋白和氧饱和度显著增加，二氧化碳分压、脱氧血红蛋白量显著下降。左心室最大上升速率（dP/dt max）分析和心电图观察表明，亚硝酸盐对心脏功能无明显影响。