Actin has been reported to enhance the superoxidegenerating activity of neutrophil NADPH oxidase in a cell-free system and to interact with p47 phox , a regulatory subunit of the oxidase. In the present study, we searched for an actin-binding site in p47phox by far-western blotting and blot-binding assays using truncated forms of p47phox . The amino-acid sequence 319-337 was identified as an actin-binding site, and a synthetic peptide of this sequence bound to actin. The sequence shows no homology to other known actin-binding motifs. It is located in the autoinhibitory region of p47 phox and includes Ser-328, a phosphorylation site essential for unmasking. Although a phosphorylation-mimetic p47phox mutant bound to actin with a lower affinity than the wild type, the same mutant interacted with filamentous actin more efficiently than the wild type. A mutant peptide p47phox (319-337, Ser328Glu) bound to filamentous actin more tightly than to monomer actin. These results suggest that p47 phox moves to cortical actin when it becomes unmasked in the cells.

The development of a 300kW-class recuperative ceramic gas turbine (CGT301) for continuous load has been conducted by the New Energy and Industrial Technology Development Organization (NEDO) as one of the programs in the Moonlight Project. In this program, the development of a ceramic heat exchanger has been carried out under the cooperation of Ishikawajima-Harima Heavy Industries, Ltd. (IHI) and NGK Insulators, Ltd. (NGK). since 1988. In this paper, the process of the development of the ceramic heat exchanger is described. A three pass shell-and-tube type of heat exchanger is considered. As the heat exchanger is to be operated at gas temperature over 825°C, the reliability is expected to be improved by applying high-temperature resistant silicon-nitride ceramics to its hot tube-bundle. In consideration of the limitation in the size of the ceramic tube-bundle, the heat exchanger was designed as the assembly of six identical modules. Tests of a single module with ceramic tube-bundle were conducted. It was confirmed that the ceramic tube-bundle had reasonable structural reliability, and that the module gave a sufficient performance i.e., temperature effectiveness and pressure drop characteristics.

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