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71.
Attachment of an adenovirus (Ad) to a cell is mediated by the capsid fiber protein. To date, only the cellular fiber receptor for subgroup C serotypes 2 and 5, the so-called coxsackievirus-adenovirus receptor (CAR) protein, has been identified and cloned. Previous data suggested that the fiber of the subgroup D serotype Ad9 also recognizes CAR, since Ad9 and Ad2 fiber knobs cross-blocked each other's cellular binding. Recombinant fiber knobs and 3H-labeled Ad virions from serotypes representing all six subgroups (A to F) were used to determine whether the knobs cross-blocked the binding of virions from different subgroups. With the exception of subgroup B, all subgroup representatives cross-competed, suggesting that they use CAR as a cellular fiber receptor as well. This result was confirmed by showing that CAR, produced in a soluble recombinant form (sCAR), bound to nitrocellulose-immobilized virions from the different subgroups except subgroup B. Similar results were found for blotted fiber knob proteins. The subgroup F virus Ad41 has both short and long fibers, but only the long fiber bound sCAR. The sCAR protein blocked the attachment of all virus serotypes that bound CAR. Moreover, CHO cells expressing human CAR, in contrast to untransformed CHO cells, all specifically bound the sCAR-binding serotypes. We conclude therefore that Ad serotypes from subgroups A, C, D, E, and F all use CAR as a cellular fiber receptor.  相似文献   
72.
Abstract

The propagation of a television (TV) signal is usually perturbed during periods of atmospheric disturbance such as in thunderstorms. The region under investigation here is situated in the coastal area of the Bay of Bengal and has experienced frequent thunderstorm activities. An investigation to study their effects on VHF signal propagation transmitted from Satkhira in Bangladesh and received at the Indian Statistical Institute, Calcutta, has been undertaken. The depths of the atmospheric disturbances within a 1?km range have been recorded and measured by acoustic sounder (sodar) operated continuously at the receiving station. The inset of the storm is marked by the enhanced signal level with deep fluctuations characteristic during the periods of thunderstorms.  相似文献   
73.
A method of determining qualitatively and quantitatively hexamidine, dibromohexamidine, dibromopropamidine and chlorhexidine in cosmetic products by means of paired ion, reverse-phase high-performance liquid chromatography (HPLC) and ultraviolet detection (UV) at 264 nm.
Détermination de l'hexamidine, du dibromohexamidine, du dibromopropamidine et de la chlorhexidine dans les produits cosmétiques  相似文献   
74.
大青叶抗菌物质提取及抗菌效果研究   总被引:10,自引:3,他引:10  
赵良忠  王放银  段林东 《食品科学》2004,25(11):138-140
研究了用水浸提法抽提大青叶中抗菌物质的方法,并通过抑菌实验检验了对细菌和霉菌的抑菌能力。正交实验结果表明最佳抽提工艺为:料水比1:20,加热时间40min,回流温度100℃:滤纸片法抑菌实验发现:大青叶提抽浓缩液(浓缩比为5:1)对大肠杆菌及枯草杆菌的最低抑菌浓度为2.77%(ml,100ml)左右,青霉,黄曲霉为0.55%(ml/100ml)左右,金黄色葡萄球为0.055%(ml/100ml)左右。  相似文献   
75.
In this paper multi-stage flow lines with intermediate buffers are approximated by two-stage lines by using repeated aggregation. The aggregation method uses restricted information of the output pattern of two-stage lines. The method is tested for the case where all production units are unreliable with exponential life-and repair-times. It appears that it performs well for most cases, provided we aggregate in the correct sequence.  相似文献   
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Abstract

A generalized information system has recently been proposed  相似文献   
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Abstract

A perturbation theory for evaluation algorithms of arithmetic expressions is applied to the generalized least-squares identification of the continuous parameters by using nonperiodic discrete data. The sampling instants are distributed in such a way that a sequence of the elemental arithmetic expressions of the identification algorithm are suboptimized according to bang-bang rules on the extrema of appropriate variation intervals. The weighting scalars in the generalized least-squares method are updated with the same purpose.  相似文献   
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