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Summary Furocoumarin photosensitization induces -prophage from lysogenicEscherichia coli cells; this effect is clearly due to the photoreaction that furocoumarins give with DNA, and it appears connected with the formation of monoadducts rather than of diadducts (cross-links).Acknowledgments. The authors wish to express their thanks to Dr L. Conventi, Microbiology Institute of Padua University, for generously donating theE. coli strains used in this work.  相似文献   
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Riassunto La sintesi degli acidi nucleici nelle cellule del tumore ascitico di Ehrlich viene inibita dall'irradiazione a 365 nm in vitro in presenza di furocumarine fotosensibilizzatrici cutanee (psoralene, bergaptene e xantotossina).  相似文献   
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Riassunto L'irradiazione a 365 nm in presenza di psoralene, furocumarina fotosensibilizzatrice cutanea non sostituita, influisce in modo diverso sulla sintesi macromoleculare in alcune cellule tumorali e normali del topo.  相似文献   
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通过与传统会计信息系统的比较,分析了计算机网络会计信息系统及网络财务所具有的特点,阐述了计算机网络会计信息系统在网络财务管理中所起的作用。  相似文献   
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给出了圆柱蜗杆及蜗轮轮齿在任意半径处弦齿厚计算的精确公式,采用了圆球法测量蜗轮直径方向的两齿间距,为了计算上的需要,引进了蜗轮弦齿厚计算斜齿轮的概念和斜齿轮测量圆棒跨距法。  相似文献   
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我国青贮玉米的研究现状及市场前景   总被引:17,自引:0,他引:17  
青贮玉米作为饲料玉米既能大幅度地提高饲料产量,同时具有较高的营养价值,在国民经济和人民生活中占有越来越重要的地位。在借鉴欧美等发达国家对青贮玉米研究成果的基础上,分析了我国发展青贮玉米的优势和潜力,提出了青贮玉米的育种策略、育种目标和主要用于家畜饲养业的有效利用途径。  相似文献   
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Significant attention in recent years has been given to obtain a better understanding of human joint ranges, measurement, and functionality, especially in conjunction with commands issued by the central nervous system. While researchers have studied motor commands needed to drive a limb to follow a path trajectory, various computer algorithms have been reported that provide adequate analysis of limb modeling and motion. This paper uses a rigorous mathematical formulation to model human limbs, understand their reach envelope, delineate barriers therein where a trajectory becomes difficult to control, and help visualize these barriers. Workspaces of a typical forearm with 9 degrees of freedom, a typical finger modeled as a 4-degree-of-freedom system, and a lower extremity with 4 degrees of freedom are discussed. The results show that using the proposed formulation, joint limits play an important role in distinguishing the barriers.  相似文献   
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Riassunto Il triptofano14C-uniformemente marcato nell'anello benzenico e il triptofano marcato14C nel metilene sono incorporati in modo significativo nella melanina del melanoma di Harding-Passey del topo.5-ossitriptofano e 5-ossitriptamina non mostrano invece una significativa incorporazione nella stessa melanina. L'incorporazione ottenuta con il triptofano marcato sia nel nucleo che nel metilene è all'incirca uguale a quella ottenuta per somministrazione di tirosina-2-C14, per cui anche il triptofano deve essere considerato un precursore delle melanine.  相似文献   
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考察了4种结构相似的醌类化合物(AQ,1,5-AQ,1,8-AQ和1,4,5,8-AQ)修饰电极对酸性红B电解脱色的催化强化作用。结果表明,酸性红B电解脱色的最佳条件:电解时间为4h,溶液pH值为3,电流密度为16mA/cm2;在此实验条件下,4种醌类化合物修饰电极提高酸性红B电解脱色效率为1.05~1.19倍,其大小顺序为1,8-AQ>1,5-AQ>AQ>1,4,5,8-AQ;通过测定1,8-AQ修饰电极电解酸性红B的脱色过程的UV谱图,发现其并未改变酸性红B脱色降解路径。  相似文献   
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