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91.
The microbial community structure and successive changes in a mesophilic ethylbenzene-degrading sulfate-reducing consortium were for the first time clarified by the denaturing gradient gel electrophoresis (DGGE) analysis of the PCR amplified 16S rRNA gene fragments. At least ten bands on the DGGE gel were detected in the stationary phase. Phylogenetic analysis of the DGGE bands revealed that the consortium consisted of different eubacterial phyla including the delta subgroup of Proteobacteria, the order Sphingobacteriales, the order Spirochaetales, and the unknown bacterium. The most abundant band C was closely related to strain mXyS1, an m-xylene-degrading sulfate-reducing bacterium (SRB), and occurred as a sole band on DGGE gels in the logarithmic growth phase that 40% ethylbenzene was consumed accompanied by sulfide production. During further prolonged incubation, the dominancy of band C did not change. These results suggest that SRB corresponds to the most abundant band C and contributes mainly to the degradation of ethylbenzene coupled with sulfate reduction. 相似文献
92.
Sone T Nagamori E Ikeuchi T Mizukami A Takakura Y Kajiyama S Fukusaki E Harashima S Kobayashi A Fukui K 《Journal of Bioscience and Bioengineering》2002,94(1):87-91
We have produced micrometer-sized calcium alginate beads referred to as "bio-beads" that encapsulate plasmid DNA molecules carrying a reporter gene. In order to evaluate the efficiency of the bio-beads in mediating genetic transfection, protoplasts isolated from cultured tobacco cells (BY-2) were transfected with bio-beads containing a plasmid that carries the modified green fluorescent protein gene CaMV35S-sGFP. With the bio-beads treatment, approximately ten-fold higher GFP expression was observed after 24 h incubation compared to that with the conventional method using a naked plasmid solution. Transfection was up to 0.22% efficient. These results indicate that bio-beads have a possibility for efficient transformation in plants. 相似文献
93.
In this paper, we propose two updated data dissemination methods to not only reduce the number of accesses to old replicas, but also to improve the data accessibility in ad hoc networks where data items are updated regularly. In the first method, when a mobile host updates a data item, it disseminates the updated data item after the flooding of with invalidation reports. In the second method, two newly connected mobile hosts disseminate updated data items with each other after the flooding with invalidation reports. 相似文献
94.
A numerical analysis technique that incorporates Voronkov's model were examined and used to estimate the distribution of defects during crystal growth. By comparisons of the distribution of the density of LSTD and the position of R-OSF in non-nitrogen-doped (non-N-doped) and nitrogen-doped (N-doped) silicon crystals, it is found that the results of the numerical analyses agree with practically evaluated data. The observations suggest that the R-OSF nucleus is a VO2 complex that is formed by bonds between oxygen atoms and residual vacancies consumed during the formation of void defects. This suggests that Voronkov's model can be used to accurately predict the generation and growth of defects in silicon crystals. This numerical analysis technique was also found to be an effective method of estimating the distribution of defects in silicon crystals during crystal growth. 相似文献
95.
A method for industrial-scale preparation of carboxypeptidase Y (CPY), which was secreted by Saccharomyces cerevisiae KS58-2D/pCY303 into the culture broth, was developed. Because the purification process consists of a few simple unit operations including only one chromatography step, a higher CPY recovery was achieved than that in the process using disrupted baker's yeast. Approximately 100 g of purified CPY powder was constantly obtained using the final culture broth from a 500-l fermentor. 相似文献
96.
Properties of graphite prepared from boron-doped pitch as an anode for a rechargeable Li ion battery
Boron-doped graphites were derived from a naphthalene-based pitch mixed with para-xylene glycol (PXG) or dimethyl para-xylene glycol (DMPXG) as a cross-linking agent and three types of boron-containing compounds as a graphitization catalyst, and their anode performances were investigated. The structural analysis of the obtained graphites revealed that PXG functioned mainly as a two-dimensional cross-linking agent during the heat treatment process and DMPXG functioned partially as a three-dimensional. The average interlayer spacing decreased and lattice constant, a0, and graphitizability increased with increasing the amount of boron atoms added. The result indicated that the carbon atoms were replaced by boron atoms. The anode performance was improved by the enhancement of graphitizability. The structural parameters and anode performance of boron-doped graphites did not depend on the kind of boron-containing compounds but the amount of boron atoms added in pitch and the kind of cross-linking agent. 相似文献
97.
98.
The electronic structures of polyfluoroacetylene and polydifluoroacetylene are discussed on the basis of the tight-binding LCAO-SCF-MO calculations under the CNDO/2 approximations. A method of preparation of these polymers is also proposed. If they can be successfully prepared, they will be promising candidates for new electric conducting materials as alternatives to polyacetylene. 相似文献
99.
Y. Fukui R. Sasaki F. Hataya T. Kashimura 《Metallurgical and Materials Transactions A》1981,12(6):1033-1039
An attempt has been made to develop a cobalt base casting superalloy (30Cr-10Ni-7W-Co) having high creep rupture strength
and ductility for first stage nozzles of gas turbines. In cobalt base superalloys, there was found to exist a close correlation
between the creep rupture strength and MC type carbide forming elements such as Ti, Nb and Zr. In cobalt base alloys with
0.25 wt pct C, precipitation and coarsening of carbides can be reduced by addition of Ti, Nb and Zr. Therefore, by adding
the optimum amount of Ti, Nb and Zr, precipitation of carbides in the alloy reaches such an amount as to give the highest
creep rupture strength. Excess addition of Ti, Nb and Zr does not improve the creep rupture strength. By adding C, creep rupture
strength of the cobalt alloy with Ti, Nb and Zr can be improved and becomes the highest at 0.40 wt pct. C. According to the
experimental results, the creep rupture strength becomes the highest at a value of (Ti + Nb + Zr)/C (atomic ratio) of about
0.3. Contrary to the expectation, it was found in this experiment that the ductility in creep rupture tests increases with
increasing carbon content up to 0.6 wt pct. 相似文献
100.
Factors that affect the efficiency of in vitro synthesis of mutant proteins that contain nonnatural amino acids were investigated. The process of the nonnatural mutagenesis consists of chemical aminoacylation of a tRNA that contains a 4-base anticodon, followed by in vitro synthesis in the presence of an mRNA that contains the corresponding 4-base codon. Detailed studies on the time courses of the synthesis revealed two major factors that suppress the yield of nonnatural mutants compared with the wild-type protein. First, a cyclic tRNA that exists as a by-product of the chemical aminoacylation inhibits the protein synthesis. Second, the very short lifetime of a tRNA aminoacylated with a nonnatural amino acid limits the protein yield. As a simple and practical way of surmounting these factors, aminoacyl tRNA was added into the in vitro system at 5 min after the start of the synthesis. The addition increased the protein yield up to the level of conventional proteins in the in vitro system. 相似文献