Kyushu Institute of Technology Academic Repository(Kyutacar)

Similar Minds: A Study on William Morris's Poetic Development under John Keats's Influence

Wed, 29 Sep 2010 22:58:59 GMT

タイトル: Similar Minds: A Study on William Morris's Poetic Development under John Keats's Influence

著者: Nijibayashi, Kei

記述: この論文は「九州工業大学研究報告. 人文・社会科学」（58号,2010.3,p17-34）に掲載された論文を査読により加筆修正し、「研究論文集－教育系・文系の九州地区国立大学間連携論文集－」（第4巻第1号,2010年）に採択されたものである。現在出版準備中であり、2010年9月30日に発行予定。

メモリアクセスを伴ったプログラムのFPGA実装に適したハードウェアアーキテクチャ

Tue, 01 Dec 2009 00:00:00 GMT

タイトル: メモリアクセスを伴ったプログラムのFPGA実装に適したハードウェアアーキテクチャ

著者: 山脇, 彰; 岩根, 雅彦

抄録: 開発時の仕様や設計の変更,及び,出荷後の変更にも柔軟に対応できるFPGAの組込みシステムへの適用が,その大容量化・高性能化を背景に広まっている.FPGAでは設計の初期段階でも試作を通した実機評価により応用プログラムのハードウェア化の効果を正確に評価できる.ただし,メモリアクセスがある場合,ハードウェアの高速性を最大限引き出すには,応用ごとにバッファとデータプリフェッチ機能を備えたメモリアクセス回路を設計する必要がある.それらのメモリアクセス回路を設計する負荷の削減は試作の更なる迅速化に重要である.本論文では,設計レベルのハードウェアアーキテクチャとして,データ処理部とバッファはreconfigurable,メモリアクセス部はprogrammableなSemi-Programmable Hardware(SPHW)を提案する.SPHWでは,メモリアクセスがロード/ストアユニットのソフトウェアプログラミングによって実現され,処理に最適なバッファがパラメータによって再構成可能レジスタファイル上に構成される.SPHWを使用すれば,プログラムとパラメータという高い抽象度でバッファとデータプリフェッチ機能をもつメモリアクセス回路を設計し得る.従来どおりHDLで専用メモリアクセス回路を設計した場合と比較して,SPHWは開発時間の52〜72%を削減し,試作と評価検討をより迅速に実施できた.更に,メモリレイテンシが隠ぺいできたならば両者の性能差は0.1%以下であり,SPHWによる試作をそのまま採用できることも確認した.

Mutation Analysis of the Interaction of B-type Cytochrome c Oxidase with its Natural Substrate Cytochrome c-551

Thu, 01 Apr 2010 00:00:00 GMT

タイトル: Mutation Analysis of the Interaction of B-type Cytochrome c Oxidase with its Natural Substrate Cytochrome c-551

著者: Kabashima, Yoshiki; Ueda, Naoaki; Sone, Nobuhito; Sakamoto, Junshi

抄録: Heme-copper oxidases in the respiratory chain are classified into three subfamilies: A-, B- and C-types. Cytochrome bo3-type cytochrome c oxidase from thermophilic Bacillus is a B-type oxidase that is thought to interact with cytochrome c through hydrophobic interactions. This is in contrast to A-type oxidases, which bind cytochrome c molecules primarily through electrostatic forces between acidic residues in the oxidase subunit II and basic residues within cytochromes. In order to investigate the substrate-binding site in cytochrome bo3, eight acidic residues in subunit II were mutated to corresponding neutral residues and enzymatic activity was measured using cytochrome c-551 from closely related Bacillus PS3. The mutation of E116, located at the interface to subunit I, decreased the kcat value most prominently without affecting the Km value, indicating that the residue is important for electron transfer. The mutation of D99, located close to the CuA site, largely affected both values, suggesting that it is important for both electron transfer and substrate binding. The mutation of D49 and E84 did not affect enzyme kinetic parameters, but the mutation of E64, E66 and E68 lowered the affinity of cytochrome bo3 for cytochrome c-551 without affecting the kcat value. These three residues are located at the front of the hydrophilic globular domain and distant from the CuA site, suggesting that these amino acids compose an acidic patch for a second substrate-binding site. This is the first report on site-directed mutagenesis experiments of a B-type heme-copper oxidase.

The cytochrome bcc-aa3-type respiratory chain of Rhodococcus rhodochrous

Thu, 01 Jul 2010 00:00:00 GMT

タイトル: The cytochrome bcc-aa3-type respiratory chain of Rhodococcus rhodochrous

著者: Kishikawa, Jun-ichi; Kabashima, Yoshiki; Kurokawa, Tatsuki; Sakamoto, Junshi

抄録: Rhodococcus rhodochrous is an active soil bacterium belonging to the Nocardia group of high GC Gram-positive bacteria. It is rich in various enzymes and thus important in the industrial production of chemicals and bioremediation. In this work, the respiratory chain of this aerobic organism was investigated and characterized. Grown under highly aerobic conditions, the membrane fraction of R. rhodochrous cells only contained a-, b- and c-type cytochromes, suggesting that it is the cytochrome bcc-aa3-type pathway that mainly operates under these conditions. In contrast, the d-type cytochrome was also present under microaerobic conditions, indicating that the alternative pathway of the bd-type oxidase works in these circumstances. In addition, the results of H+/O ratio measurements indicate that these two pathways have different energy efficiencies.