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Your search keyword '"Nakazawa, Keisuke"' showing total 43 results
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43 results on '"Nakazawa, Keisuke"'

9. Oxygenic Phototrophs Need ζ-Carotene Isomerase (Z-ISO) for Carotene Synthesis: Functional Analysis in Arthrospira and Euglena.

Author

Sugiyama, Kenjiro, Takahashi, Koh, Nakazawa, Keisuke, Yamada, Masaharu, Kato, Shota, Shinomura, Tomoko, Nagashima, Yoshiki, Suzuki, Hideyuki, Ara, Takeshi, Harada, Jiro, and Takaichi, Shinichi

Subjects
ISOMERASES, DUNALIELLA, FUNCTIONAL analysis, CAROTENES, AMINO acid sequence, EUGLENA gracilis, SULFUR bacteria, LYCOPENE
Abstract

For carotenogenesis, two biosynthetic pathways from phytoene to lycopene are known. Most bacteria and fungi require only phytoene desaturase (PDS, CrtI), whereas land plants require four enzymes: PDS (CrtP), ζ-carotene desaturase (ZDS, CrtQ), ζ-carotene isomerase (Z-ISO) and cis -carotene isomerase (CrtISO, CrtH). The gene encoding Z-ISO has been functionally identified in only two species, Arabidopsis thaliana and Zea mays , and has been little studied in other organisms. In this study, we found that the deduced amino acid sequences of Arthrospira Z-ISO and Euglena Z-ISO have 58% and 62% identity, respectively, with functional Z-ISO from Arabidopsis. We studied the function of Z-ISO genes from the cyanobacterium Arthrospira platensis and eukaryotic microalga Euglena gracilis. The Z-ISO genes of Arthrospira and Euglena were transformed into Escherichia coli strains that produced mainly 9,15,9′- tri-cis -ζ-carotene in darkness. In the resulting E. coli transformants cultured under darkness, 9,9′- di-cis -ζ-carotene was accumulated predominantly as Z-ISO in Arabidopsis. This indicates that the Z-ISO genes were involved in the isomerization of 9,15,9′- tri-cis -ζ-carotene to 9,9′- di-cis -ζ-carotene in darkness. This is the first functional analysis of Z-ISO as a ζ-carotene isomerase in cyanobacteria and eukaryotic microalgae. Green sulfur bacteria and Chloracidobacterium also use CrtP, CrtQ and CrtH for lycopene synthesis as cyanobacteria, but their genomes did not comprise Z-ISO genes. Consequently, Z-ISO is needed in oxygenic phototrophs, whereas it is not found in anoxygenic species. [ABSTRACT FROM AUTHOR]

Published
2020
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10. Hyperinsulinemic Normoglycemia during Cardiac Surgery Reduces a Composite of 30-day Mortality and Serious In-hospital Complications

Author

Duncan, Andra E., primary, Sessler, Daniel I., additional, Sato, Hiroaki, additional, Sato, Tamaki, additional, Nakazawa, Keisuke, additional, Carvalho, George, additional, Hatzakorzian, Roupen, additional, Codere-Maruyama, Takumi, additional, Abd-Elsayed, Alaa, additional, Bose, Somnath, additional, Said, Tamer, additional, Mendoza-Cuartas, Maria, additional, Chowdary, Hyndhavi, additional, Mascha, Edward J., additional, Yang, Dongsheng, additional, Gillinov, A. Marc, additional, and Schricker, Thomas, additional

Published
2018
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11. Object Contour Shape Modeling using a Cyclic Self-Organizing Map

Author

nakazawa, keisuke, Aoki, Kota, and NAGAHASHI, HIROSHI

Subjects
Self-Organizing Map, 自己組織化マップ, Shape Modeling, シェイプモデリング
Abstract

形状をどのように数値化し，その後の物体認識，検出，変形等の処理を効率的に行えるようにするかは非常に重要な前処理である．一方近年，与えられたデータから，隠れた規則性や，潜在的な変数を発見する統計的機械学習の発展が著しいものとなっている．データから一見人にはわからないような隠れた規則性，潜在的な変数を獲得することができるという利点を持つ．そこで本研究では，教師なし学習手法である環状自己組織化マップにより，物体輪郭線の特徴表現を行う．従来手法では凹凸の多い複雑な物体に対しては，物体輪郭線に沿った近似表現が困難であった問題を，点順序を考慮した割当問題を解くことで解決する．また，それを用いた物体輪郭線の特徴表現手法を提案する，シルエット認識を通し提案手法の有効性を検証する．, Radiation therapy is one of the effective cancerous treatment method, because of less side effects to the patient. This treatment irradiates radiation beam into cancer cell. Since the body organ is moving while the therapy, cancer must be tracked quantitatively with the motion of the organ. Motion quantification may be performed by tracking the pixels of the Ultrasound image. Ultrasound imaging is a noninvasive method to analyze the motion of the organ. However, due to the noise and less texture information, it is hard to perform tracking for a longtime. Therefore, this work proposes a robust method to track the motion of the organ by utilizing online learning mechanism.

Published
2013

28. Fabrication of 0.1 µm Patterns Using an Alternating Phase Shift Mask in ArF Excimer Laser Lithography

Author

Keisuke Nakazawa, Keisuke Nakazawa, primary, Masaya Uematsu, Masaya Uematsu, additional, Toshio Onodera, Toshio Onodera, additional, Kazuya Kamon, Kazuya Kamon, additional, Tohru Ogawa, Tohru Ogawa, additional, Shigeyasu Mori, Shigeyasu Mori, additional, Makoto Takahashi, Makoto Takahashi, additional, Takeshi Ohfuji, Takeshi Ohfuji, additional, Hiroshi Ohtsuka, Hiroshi Ohtsuka, additional, and Masaru Sasago, Masaru Sasago, additional

Published
1997
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42. Stabilization of ZrSixOyFilms by Irradiation with an ArF Excimer Laser

Author

Keisuke Nakazawa, Keisuke Nakazawa, Takahiro Matsuo, Takahiro Matsuo, Toshio Onodera, Toshio Onodera, Tohru Ogawa, Tohru Ogawa, and Hiroaki Morimoto, Hiroaki Morimoto

Abstract

ZrSixOyis a candidate material for fabricating attenuated phase-shift masks used in ArF excimer laser lithography. To investigate the durability mechanism of ZrSixOyfilms following irradiation with an ArF excimer laser, we analyzed the films chemically and physically. The phase shift and the transmittance of a transmissive film with a high oxygen concentration increases and decreases, respectively, with irradiation. This is because of an increase of Si-O-Zr bond structures. The phase shift and the transmittance of an absorptive film with a low oxygen concentration decreases and increases, respectively, with irradiation because of photooxidation at the surface. The oxidation leads to the formation of Si-O-Zr and Si-O-Si bond structures in the films. Both films are stabilized by irradiation with a large irradiation energy. We interpret that both films are stabilized by the formation of Si-O-Zr bond structures, such as zircon, with saturation of oxygen concentrations at the surface.

Published
2000
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43. Fabrication of 0.13-µmDevice Patterns by Argon Fluoride Excimer Laser Lithography with Practical Resolution Enhancement Techniques

Author

Ogawa, Tohru, Uematsu, Masaya, Onodera, Toshio, Nakazawa, Keisuke, Takahashi, Makoto, Ohfuji, Takeshi, Ohtsuka, Hiroshi, and Sasago, Masaru

Abstract

This paper presents the formation results of 0.13-µ m device patterns using argon fluoride (ArF) excimer laser lithography that does not incorporate strong resolution enhancement techniques such as levenson type phase-shifting mask or quadrupole illumination. Device patterns of 0.13-µ m can be fabricated by ArF excimer laser lithography when a high performance single-layer photoresist, an anti-reflective layer, an attenuated phase-shifting mask with an off-axis illumination are used. A 0.5-µ m depth-of-focus with a 10.8% exposure latitude can be obtained. Furthermore, 0.12-µ m-rule gate patterns of memory and logic devices can be fabricated. A 1.0-µ m depth-of-focus for a 0.13-µ m pattern will be achieved.

Published
1997
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