1-(substituted)benzyl-5-aminoimidazole-4-carboxamides are potent orally active inhibitors of Trypanosoma cruzi in mice

1-(Substituted)benzyl-5-aminoimidazole-4-carboxamides are potent orally active inhibitors of Trypanosoma cruzi infections in mice. The most active compounds are the 1-(4-chlorobenzyl)- and 1-(3,4-dichlorobenzyl)-analogs (L-153,094 [2] and L-153,153 [4], resp.) which are approximately 7-fold more potent upon oral administration than nifurtimox (Lampit) in suppressing parasite levels in the blood of mice with acute Trypanosoma cruzi infections.     

测井资料分析系统接口电路设计

从一种超声模拟测井记录的井下信号、深度信号送微机处理的实际要求出发，分析井下信号数据采集的工作原理，阐述了与１２位Ａ／Ｄ转换器实时配套工作的双存储体工作时序。通过对深度信号的解调，提出了一种解决４ＦＳＫ解调的有效方法。     

BP网络的抗干扰性研究及误差分析

从ＢＰ网络对信息存储的分布式特点出发，分析了连接权系数及输入变化对输出的影响，探讨了ＢＰ网络的容错性及抗干扰特性，得出了一些有益的结论。     

Effect of actinomycin D on Trypanosoma cruzi

Viable metacyclic forms of T. cruzi, Y strain, treated with an adequate dose of actinomycin D (50 micrograms Act-D/ml/10(7) parasites/ml for 72 h at 28 degrees C) showed the following properties: 1) they lost their ability to replicate in culture medium, in blood and in tissues of normal mice and were no longer able to incorporate tritiated thymidine; 2) they could not penetrate into Vero cells and could not replicate inside normal macrophages; 3) they retained their immunogenicity and the ability to protect mice against a virulent infection; 4) they did not induce histological lesions as described in chronic experimental Chagas' disease.     

任意波形合成系统硬件设计

提出并分析了任意波形合成系统（ＡＷＳ）──一种高度智能化的计算机仪器的几种典型结构及其特点，着重讨论了ＰＣ总线式任意波形合成系统的系统组成及各部分硬件电路设计的关键技术     

Wireless Location Determination for Mobile Objects Based on GSM in Intelligent Transportation Systems

1 .INTRODUCTIONTheabilityofpositioningmobileobjects (MOs) ,in cludingvehiclesandtravelersholdingmobiletermi nals,isafundamentalfunctionforsomeITSsubsys tems,suchasemergencyrescue,securitysystem ,au tomaticnavigationsystem ,andtrafficinducementsystem[1 ] .Atpresent,therearethreedominatingtypes[2 ]ofwirelesspositioningtechnologies,i.e.positioningbasedonsatellites,positioningbasedondedicatedcommunicationsystemsandpositioningbasedonpub liclandwirelesstelecommunicationsystems (PLMTS) ,respe…     

Overcast tests with clock-shifted pigeons

In order to investigate the pigeon's compass mechanism, a series of overcast tests with clock-shifted birds were run at two familiar release sites. While controls were able to assume a correct homeward direction, the experimental birds' initial orientation cannot be explained either on the basis of a time-compensated sun compass or of a time-independent magnetic compass. Speculative explanations of our paradoxical results are attempted.     

Sequence-directed curvature of DNA

DNAs from both prokaryotic and eukaryotic organisms have yielded restriction fragments which manifest markedly anomalous electrophoretic behaviour (reduced mobility) when run on polyacrylamide gels. We have shown previously that the abnormal electrophoretic behaviour of one such fragment is a consequence of stable curvature of the helix axis in solution. The molecules involved tend to contain oligo(dA)-oligo(dT) runs which are approximately in-phase with the helix repeat; however, the precise structural elements responsible for DNA curvature have not been identified. One popular model for curvature invokes a non-coplanar 'wedge-like' conformation of ApA/TpT dinucleotide pairs. Despite a lack of direct evidence in support of this model, it has been used to provide quantitative estimates of curvature. To critically evaluate the ApA wedge model, we have performed an electrophoretic analysis of a series of closely related DNA polymers in which oligo(dA)-oligo(dT) runs of different polarity were compared. We conclude that ApA dinucleotide wedges cannot account for DNA curvature. Therefore, quantitative estimates for ApA wedge deformations, based solely on apparent curvature, cannot be correct.     

Re-routing of a secretory protein by fusion with human growth hormone sequences

Cells with electron-dense secretory vesicles use them to store only specialized secretory products such as peptide hormones; other types of secreted proteins are externalized by an alternative, constitutive route. One possible mechanism for such segregation is that proteins destined for dense secretory vesicles contain unique 'sorting domains' that allow for selective targeting. Here, we set out to determine whether a constitutively secreted protein could be diverted to the dense secretory vesicles by attachment to a peptide hormone sequence. We made use of the ability of the mouse pituitary tumour cell, AtT-20, to correctly sort exogenous secretory proteins introduced into them by DNA transfection. We constructed a plasmid encoding a hybrid protein in which a constitutively secreted viral protein was fused to the carboxy terminus of human growth hormone (hGH). Cells expressing the hybrid protein were found to target it to dense secretory vesicles with an efficiency close to that observed for the parental hGH. These results support the hypothesis that sorting domains on peptide hormones direct their packaging into dense secretory vesicles. The results also suggest that proteins secreted by the constitutive pathway either do not contain any sorting domain, or their sorting signals can be overridden by those which direct peptide hormones.