Keisuke Araki

Utsunomiya University

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Studies on Constituents of Crude Drugs. I. Alkaloids of Symphytum officinale LINN.

Chemical and Pharmaceutical Bulletin (1968)

Tsutomu Furuya Keisuke Araki

Two pyrrolizidine alkaloids, symphytine (I), a new compound, and echimidine (II) have been isolated from the dried roots of Symphytum officinale. Both have a retronecine nucleus esterified on the 7-hydroxyl group with angelic acid. The other esterifying acid of symphytine is l-viridifloric acid (III), identical with the authentic sample. The structure of symphytine, a diastereoisomer of echiumine (retronecine esterified with angelic acid and trachelanthic acid), has been confirmed. A large amount of allantoin has also been isolated from the dried roots and leaves.

Allantoin

Diastereomer

Boraginaceae

10.1248/cpb.16.2512

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Citations (40)

Orthonormal Divergence-Free Wavelet Analysis of Spatial Correlation between Kinetic Energy and Nonlinear Transfer in Turbulence

Springer eBooks (2003)

Keiji Kishida Keisuke Araki

Intermittency

Energy cascade

10.1007/978-4-431-67002-5_17

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Fundamental ray aberration analysis: extension of ray matrix analysis to the third-order region using a four-element fundamental ray vector

Applied Optics (2020)

Kentaro Mori Yoshio Hayasaki Keisuke Araki

We have developed a new fundamental ray aberration analysis that extends conventional ray matrix analysis to the third-order region using a four-element fundamental ray vector. This analysis method can analyze the factors in the generation of the Seidel aberration coefficients by separating them into the transform characteristics of rays unique to the optical system and paraxial trace values representing the conjugate relationship. In establishing this analysis, we first introduce the fundamental ray aberration, and we present calculation formulae for the fundamental ray aberration coefficients of a co-axial rotationally symmetric optical system. Numerical examples employing these analysis results are shown, and it is confirmed that the causes of the Seidel aberration coefficients can be analyzed.

10.1364/ao.389600

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Nonlocal Nature of the Energy Transfer to Magnetic Fields in Magnetohydrodynamic Turbulence

Annual report of National Institute for Fusion Science/Annual report (2009)

Keisuke Araki Hideaki Miura

Magnetohydrodynamic Turbulence

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ChemInform Abstract: Cobalt‐Catalyzed Cross‐Coupling Reaction of Arylzinc Reagents with Ethyl Bromodifluoroacetate.

ChemInform (2013)

Keisuke Araki Munenori Inoue

10.1002/chin.201341067

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JICST factual database. (2). JICST chemical dictionary database.

Journal of Information Processing and Management (1988)

Keisuke Araki

有機化合物の体系名を解析し, 原子結合表を自動作成するプログラムを開発した。体系名と化合物のさまざまな慣用名を組み合わせて入力した化合物データベースを紹介する。従来のものにない, 立体化学を正しく扱える機能を持ち, 検索や表示に反映できる。化審法, 労安法, RTECS等に収載の化合物も登録しており, JICSTファク卜系データベースの中心的辞書として, これらとの相関検索もできる。

10.1241/johokanri.31.21

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Citations (2)

Expansion of JICST Chemical Dictionary Database. Registration of mixture type substances and substance indexing.

Journal of Information Processing and Management (1991)

Mimiko KIMURA Keisuke Araki Chikako Maeda Ken'ichi HINATSU Kazuaki Suzuki

JICSTファクトデータベースシステムの中心的辞書としてオンラインサービスされているJICST化合物辞書データベースは,従来の有機低分子化合物に加えて,1989年から混合物タイプ物質の処理を開始した。また1990年1月からは文献に対してJICST化合物辞書命名法に則った物質索引を試行的に開始した。この物質索引の内容は,JOIS-IIIの90ファイルから検索可能である。混合物のデータ構造,入力と機械処理,検索法および物質索引の流れを中心に,化合物辞書データベースの現状について述べた。

Database index

10.1241/johokanri.34.141

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Citations (3)

MHDダイナミクスにおけるエネルギー輸送のウェーブレット解析(乱流と輸送現象:コーヒーカップから宇宙まで)

RIMS Kokyuroku (2007)

Keisuke Araki Hideaki Miura

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Enantioselective Synthesis of the Spirotetracyclic Carbon Core of Mangicols by Using a Stereoselective Transannular Diels–Alder Strategy

Angewandte Chemie International Edition (2003)

Keisuke Araki Keiji Saito Hirokazu Arimoto Daisuke Uemura

“TADA!” is not the trumpet fanfare but the transannular Diels–Alder reaction concluding the synthesis of the tetracyclic core of the mangicols, a family of marine sesterterpenes. Further highlights in the synthesis include a novel chlorination and an intramolecular Nozaki–Hiyama–Kishi coupling reaction. Bn=benzyl.

Diels–Alder reaction

10.1002/anie.200351750

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Citations (39)

Third-order aberration analysis of an off-axial optical system

Optical Review (2015)

Tsuyoshi Wakazono Toyohiko Yatagai Keisuke Araki

Optical aberration

10.1007/s10043-015-0156-8

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Citations (4)