Synthesis of an ochre suppressor tRNA gene and expression in mammalian cells.

Journal ArticleWe have used site-specific mutagenesis to change the anticodon of a Xenopus laevis tyrosine tRNA gene so that it would recognize ochre codons. This tRNA gene is expressed when amplified in monkey cells as part of a SV40 recombinant and efficiently suppresses termination at both the ochre codon separating the adenovirus 2 hexon gene from a 23-kd downstream gene and the ochre codon at the end of the NS1 gene of influenza virus A/Tex/1/68. Termination at an amber codon of a NS1 gene of another influenza virus strain was not suppressed by the (Su+) ochre gene suggesting that in mammalian cells amber codons are not recognized by ochre suppressor tRNAs. Finally, microinjection into mammalian cells of both (Su+) ochre tRNA genes and selectible genes containing ochre nonsense mutations gives rise to colonies under selective conditions. We conclude that it should be possible to isolate a wide assortment of mammalian cell lines with ochre suppressor activity

QoS routing in cluster OLSR by using the artificial intelligence model MSSP in the big data environnment

The most complex problems, in data science and more specifically in artificial intelligence, can be modeled as cases of the maximum stable set problem (MSSP). this article describes a new approach to solve the MSSP problem by proposing the continuous hopfield network (CHN) to build optimized link state protocol routing (OLSR) protocol cluster. our approach consists in proposing in two stages: the first acts at the level of the choice of the OLSR master cluster in order to quickly make a local minimum using the CHN, by modeling the MSSP problem. As for the second step, the objective is the improvement of the precision making a solution of efficient at the first rank of neighborhood as a linear constraint, and at the end, to find the resolution of the model using the CHN. We will show that this model determines a good solution of the MSSP problem. To test the theoretical results, we propose a comparison with a classic OLSR

High Temperature Microplasticity of Fine-Grained Ceramics

Several fine-grained ceramics exhibit enhanced ductility or even structural superplasticity at high temperature. Grain boundaries play a dominant role in the deformation process of these materials which usually involves diffusion-accommodated grain boundary sliding. Sliding is either lubricated by an amorphous intergranular phase or takes place by glide and climb of grain boundary dislocations. At high temperature, anelastic deformation precedes plastic deformation and stems from the short range motion of lattice defects, such as dislocations and grain boundaries. The energy loss ("mechanical loss") associated with such motion can be measured by using the technique of mechanical spectroscopy. Moreover, at the onset of plasticity ("microplasticity"), long range irrecoverable motion of defects contributes to additional mechanical loss. Mechanical loss spectra may then give an insight into mechanisms operating at the transition between anelastic and plastic deformation. As an illustration, the spectra of three fine-grained ceramics (Si3N4, ZrO2, Al2O3) are presented. In all cases, anelastic relaxation phenomena (peak and background) have been observed at high temperature (>1200K), bearing a close relation with creep behaviour. Their analysis permits to distinguish between different types of microstructural elements : bulk regions of amorphous intergranular phase at triple points, grain boundaries separated by a thin glassy film and "clean" grain boundaries