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981.
982.
983.
The processing endoribonuclease RNase E (Rne), which is encoded by the rne gene, is involved in the maturation process of messenger RNAs and a ribosomal RNA. A number of deletions were constructed in order to assess functional domains of the rne gene product. The expression of the deletion constructs using a T7 promoter/RNA polymerase overproduction system led to the synthesis of truncated Rne polypeptides. The smallest gene fragment in this collection that was able to complement a temperature sensitive rnets mutation and to restore the processing of 9 S RNA was a 2.3-kilobase pair fragment with a 1.9-kilobase pair N-terminal coding sequence that mediated synthesis of a 70.8-kDa polypeptide. Antibodies raised against a truncated 110-kDa polypeptide cross-reacted with the intact rne gene product and with all of the shorter C-terminal truncated polypeptides, indicating that the N-terminal part of the molecule contained strong antigenic determinants. Furthermore, by analyzing the Rne protein and the truncated polypeptides for their ability to bind substrate RNAs, we were able to demonstrate that the central part of the Rne molecule encodes an RNA binding region. Binding to substrate RNAs correlated with the endonucleolytic activity. RNAs that are not substrates for RNase E did not bind to the protein. The two mutated Rne polypeptides expressed from the cloned gene containing either the rne-3071 or ams1 mutation also had the ability to bind 9 S RNA, while their enzymatic function was completely abolished. The data presented here suggest that the endonucleolytic activity is encoded by the N-terminal part of the Rne protein molecule and that the central part of it possesses RNA binding activity. 相似文献
984.
Available data on the chemical composition and structure of sialon phases are reviewed. Properties of the phases and their potential applications are discussed. 相似文献
985.
Andrea Omicini Alessandro Ricci Mirko Viroli 《Electronic Notes in Theoretical Computer Science》2006,150(3):21-36
Human intelligence has evolved along with the use of more and more sophisticated tools, allowing Homo Faber (from Homo Habilis to Homo Sapiens Sapiens) to cope with environment changes, as well as to adapt the environment to his needs. Analogously, in this seminal paper we introduce the notion of Agens Faber, conveying the idea that agent intelligence should not be considered as separated by the agent ability to perceive and affect the environment—and so, that agent intelligence is strictly related to the artefacts that enable, mediate and govern any agent (intelligent) activity.
Along this line, we first discuss the notion of artefact for MAS in general, then we try to devise out the admissible / required / desirable features of an artefact for MAS. We elaborate on the many sorts of possible relations between agents and artefacts, focusing in particular on the issue of the rational exploitation of artefacts, and also rough out a possible taxonomy of artefacts for MAS. 相似文献
986.
987.
Kapustin V. M. Bogolyubov Ya. Klimova L. Z. 《Chemistry and Technology of Fuels and Oils》1989,25(5):265-268
Chemistry and Technology of Fuels and Oils - 相似文献
988.
The crystallization of Pd40Ni40P20 glass, produced by melt-spinning in air, has been studied by optical metallography. Crystallization is predominantly from the surface and is more prevalent on the wheel-side. The non-uniformity is attributed to variation in quench rate during production. A three-stage anneal permits crystals which have nucleated at the surface to be identified and their size distribution to be analysed. The surface nucleation is heterogeneous and appears to be hindered by mild oxidation. The annealing atmosphere markedly affects the surface crystallization behaviour, as does removal of the original ribbon surface. When nucleation is sparse, partial crystallization causes the development of noticeable relief on the sample surfaces. 相似文献
989.
The rôle of saponins in the undesirable sensory properties of the dried pea P sativum is reported. The sensory properties of isolated soyasaponin I are defined and described as bitter, astringent and metallic. The distribution of saponin in various air-classified pea flour fractions shows that the protein-rich fraction may contain sufficient saponin to cause undesirable tastes. 相似文献
990.
Tsai Jeanne L.; Miao Felicity F.; Seppala Emma; Fung Helene H.; Yeung Dannii Y. 《Canadian Metallurgical Quarterly》2007,92(6):1102
Previous studies have found that in American culture high-arousal positive states (HAP) such as excitement are valued more and low-arousal positive states (LAP) such as calm are valued less than they are in Chinese culture. What specific factors account for these differences? The authors predicted that when people and cultures aimed to influence others (i.e., assert personal needs and change others' behaviors to meet those needs), they would value HAP more and LAP less than when they aimed to adjust to others (i.e., suppress personal needs and change their own behaviors to meet others' needs). They test these predictions in 1 survey and 3 experimental studies. The findings suggest that within and across American and Chinese contexts, differences in ideal affect are due to specific interpersonal goals. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献