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It was found that actin solutions contain ATP. Experiments in which hexokinase and creatine were added to actin show that the ensuing dephosphorylation of ATP affects actin so that it will not polymerize.  相似文献   
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Propanil is one of the major herbicides used on rice-paddies and is thought to produce adverse health effects through the action of its metabolite 3,4-dichloroaniline (3,4-DCA). T he feasibility of monitoring human exposure to propanil on the basis of 3,4-DCA adducts to haemoglobin (Hb) was investigated. We developed a method based on gas chromatography negative ion chemical ionization-mass spectrometry (NICI-GC-MS) to quantify 3,4-DCA released from human Hb after alkaline hydrolysis of the protein. 3,4-DCA-Hb adducts were identified in agricultural workers exposed to propanil and were detectable even 4 months after the last herbicide application. Urine samples collected at the same time had no measurable level of 3,4-DCA. 3,4-DCA-Hb adducts might be useful for monitoring human exposure to 3,4-DCA from agricultural sources.  相似文献   
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亚洲古近纪早期的年代学和哺乳动物群更替(英文)   总被引:2,自引:1,他引:1  
对广东南雄盆地、江西池江盆地、安徽潜山盆地、湖南衡阳盆地和内蒙古二连盆地古新世和早始新世沉积物进行的生物地层学、化学地层学和磁性地层学研究,第一次给亚洲早古近纪地层框架提供了严格的年代限定。亚洲古新世和早始新世地层划分为4个生物年代单位(陆生哺乳动物期),从老到新为上湖期、浓山期、格沙头期和伯姆巴期4个亚洲陆生哺乳动物期。南雄盆地古地磁数据显示上湖期的底界约位于C29r的上2/3位置。南雄盆地的古地磁资料及池江盆地最新的古地磁和同位素结果显示上湖-浓山期界线在C27n的上部和C26r的下部之间,接近C27n-C26r转换界面。这一记录支持将上湖-浓山期的界线与北美陆生哺乳动物期中的Torrejonian-Tiffanian期以及海相记录中丹尼-塞兰特期(Danian-Selandi-an)的界线相对比。二连盆地古地磁和同位素研究表明典型的格沙头动物群延续至C24r,并且可能向下延伸至C25r和C26n。南雄盆地的记录指示浓山组和古城村组可能相当于C26r的上部。这些结果表明亚洲哺乳动物分期中的浓山-格沙头期的界线可能在北美哺乳动物分期的Tiffanian期中。衡阳盆地的古地磁和同位素证据指示,以短暂的碳同位素漂移为标志的古新世-始新世界线出现在栗木坪组和岭茶组之间,位于C24r中,与海相记录中的坦尼特-伊普里斯期(Thanetian-Ypresian)界线一致。伯姆巴期岭茶动物群的时代似乎与北美Wa-satchian-0带的动物群可以比较。上湖期和浓山期动物群主要由亚洲特有的动物组成。发生在上湖期和浓山期界线处的动物群更替,与北美Torrejonian-Tiffanian期界线以及丹尼-塞兰特期界线一致。在相隔很远的生态系统上的这种巧合,可能反映出各自独立的对气候变化的生态和/或进化上的响应。格沙头动物群的地方性色彩更弱,有与北美Clarkforkian期动物群共有的属一级分类单元。伯姆巴动物群是全球性的。现生哺乳动物各目在格沙头-伯姆巴期界线处突然出现,与北美和欧洲的记录一致,显示动物群的更替与古新世-始新世界线处短暂出现的全球变暖事件(又称古新世-始新世高温事件)有关。  相似文献   
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Although many accounts of transnational religious movements emphasize mobility and communication, equally important are efforts by both political actors and religious leaders to carve out distinctive national forms of religion. In this article I examine dilemmas faced by Muslims in France who seek both to remain part of the global Muslimcommunity and to satisfy French demands for conformity to political and cultural norms. I consider the history of immigration and the importance of French notions of laïcité but emphasize the structural problem of articulating a global religious field onto a self-consciously bounded French nation-state. I then draw on recent fieldwork in Paris to analyze two recent public events in which attempts by Muslim public intellectuals to develop an "Islam of France" are frustrated by internal, structural tensions concerning religious authority and political legitimacy, and not simply by a conflict between "Muslims" and "France."  相似文献   
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Abstract The warty birch caterpillar Drepana bilineata produces two distinct types of vibrational signals (mandible drumming and anal scraping) during interactions with conspecifics. Vibrational signalling is characterized using standard and high‐speed videography synchronized with laser‐doppler vibrometry, and behavioural experiments test the hypothesis that signalling functions to advertise occupancy of birch (Betula) leaves. Drumming involves raising the head and striking the leaf with the sharp edges of the open mandibles. Anal scraping involves dragging a pair of specialized oar‐shaped setae against the leaf surface. Staged encounters between leaf residents and conspecific intruders result in the resident signalling, with rates increasing as the intruder moves closer. Intruders signal significantly less often than residents. Conflicts are typically resolved within a few minutes, with the resident winning in 61% of the trials, and the intruder winning in 6%. Contests that last more than 30 min are deemed ‘ties’ and comprise the remaining 33% of trials. The results support the hypothesis that vibrational signals function to advertise leaf occupancy. Vibrational communication is believed to be widespread in Drepanoidea caterpillars, but has only been described in two species to date: D. bilineata (present study) and Drepana arcuata. It is proposed that differences in territorial behaviour and signalling between these species are related to their relative investments in silk leaf mats and shelters. The proximate and ultimate bases for the evolution of vibrational communication in caterpillars are discussed.  相似文献   
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