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723 results on '"Nagai, Ryoji"'

1. Stable beam operation of approximately 1 mA beam under highly efficient energy recovery conditions at compact energy-recovery linac

Author

Sakai, Hiroshi, Arakawa, Dai, Furuya, Takaaki, Haga, Kaiichi, Hagiwara, Masayuki, Harada, Kentaro, Honda, Yosuke, Honma, Teruya, Kako, Eiji, Kato, Ryukou, Kojima, Yuuji, Konomi, Taro, Matsumura, Hiroshi, Miura, Taichi, Miura, Takako, Nagahashi, Shinya, Nakai, Hirotaka, Nakamura, Norio, Nakanishi, Kota, Nigorikawa, Kazuyuki, Nogami, Takashi, Obina, Takashi, Qiu, Feng, Sagehashi, Hidenori, Sakanaka, Shogo, Shimada, Miho, Tadano, Mikito, Takahashi, Takeshi, Takai, Ryota, Tanaka, Olga, Tanimoto, Yasunori, Toyoda, Akihiro, Uchiyama, Takashi, Umemori, Kensei, Yamamoto, Masahiro, Yoshida, Go, Nishimori, Nobuyuki, Hajima, Ryoichi, Nagai, Ryoji, and Sawamura, Masaru

Subjects
Physics - Accelerator Physics
Abstract

A compact energy-recovery linac (cERL) has been un-der construction at KEK since 2009 to develop key technologies for the energy-recovery linac. The cERL began operating in 2013 to create a high-current beam with a low-emittance beam with stable continuous wave (CW) superconducting cavities. Owing to the development of critical components, such as the DC gun, superconducting cavities, and the design of ideal beam transport optics, we have successfully established approximately 1 mA stable CW operation with a small beam emittance and extremely small beam loss. This study presents the details of our key technologies and experimental results for achieving 100% energy recovery operation with extremely small beam loss during a stable, approximately 1 mA CW beam operation., Comment: 11 pages, 16 figures

Published
2024

9. Generating carrier-envelope-phase stabilized few-cycle pulses from a free-electron laser oscillator

Author

Hajima, Ryoichi and Nagai, Ryoji

Subjects
Physics - Accelerator Physics
Abstract

We propose a scheme to generate carrier-envelope-phase (CEP) stabilized few-cycle optical pulses from a free-electron laser oscillator. The CEP stabilization is realized by continuous injection of CEP-stabilized seed pulses from an external laser to the FEL oscillator whose cavity length is perfectly synchronized to the electron bunch repetition. Such CEP-stabilized few-cycle FEL pulses will be an efficient driver for exploring high-harmonic generation at energies 1-10~keV for attosecond and zeptosecond science, broad-band x-ray optical frequency combs and coherent control of chemical reaction., Comment: 14 pages, 5 figures

Published
2017
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11. Prenylflavonoids isolated from Epimedii Herba show inhibition activity against advanced glycation end-products.

Author

Nakashima, Keisuke, Miyashita, Hiroyuki, Yoshimitsu, Hitoshi, Fujiwara, Yukio, Nagai, Ryoji, Ikeda, Tsuyoshi, Baiseitova, Aizhamal, and Chen, Bing

Subjects
ADVANCED glycation end-products, NEUROPATHY, MONOCLONAL antibodies, ENZYME-linked immunosorbent assay, PROPOLIS
Abstract

Introduction: As inhibitors of advanced glycation end products (AGEs), such as pyridoxamine, significantly inhibit the development of retinopathy and neuropathy in rats with streptozotocin-induced diabetes, treatment with AGE inhibitors is believed to be a potential strategy for the prevention of aging, age- related diseases, and lifestyle-related diseases, including diabetic complications. In the present study, the MeOH extract of Epimedii Herba (EH; aerial parts of Epimedium spp.) was found to inhibit the formation of NE-(carboxymethyl)lysine (CML) and N"-(carboxymethyl) arginine (CMA) during the incubation of collagen- derived gelatin with ribose. Materials and methods: EH was purchased from Uchida Wakan-yaku Co., and a MeOH extract was prepared. Several steps of column chromatography purified the extract. Each fraction was tested for inhibitory activity by ELISA using monoclonal antibodies for CML and CMA. Results: After activity-guided fractionation and purification by column chromatography, three new prenylflavonoids [named Koreanoside L (1), Koreanoside E1 (2), and Koreanoside E2 (3)] and 40 known compounds (4-43) were isolated from EH, and their inhibitory effects against CML and CMA formation were tested. Among these, epimedokoreanin B (8), epimedonin E (21), epicornunin B (22), and epicornunin F (24) inhibited the formation of both CML and CMA, with epimedokoreanin B (8) having the most potent inhibitory effect among the isolated compounds. To obtain the structure-activity relationships of 8, the phenolic hydroxy groups of 8 were methylated by trimethylsilyl-diazomethane to afford the partially and completely methylated compounds of 8. Prenyl derivatives of propolis (artepillin C, baccharin, and drupanin) were used in the assay. Discussion: As only 8 showed significant activity among these compounds, the catechol group of the B ring and the two prenyl groups attached to the flavanone skeleton were essential for activity. These data suggest that 8 could prevent the clinical complications of diabetes and age-related diseases by inhibiting AGEs. [ABSTRACT FROM AUTHOR]

Published
2024
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14. Construction and commissioning of the compact energy-recovery linac at KEK

Author

Akemoto, Mitsuo, Arakawa, Dai, Asaoka, Seiji, Cenni, Enrico, Egi, Masato, Enami, Kazuhiro, Endo, Kuninori, Fukuda, Shigeki, Furuya, Takaaki, Haga, Kaiichi, Hajima, Ryoichi, Hara, Kazufumi, Harada, Kentaro, Honda, Tohru, Honda, Yosuke, Honma, Teruya, Hosoyama, Kenji, Kako, Eiji, Katagiri, Hiroaki, Kawata, Hiroshi, Kobayashi, Yukinori, Kojima, Yuuji, Kondou, Yoshinari, Tanaka, Olga, Kume, Tatsuya, Kuriki, Masao, Matsumura, Hiroshi, Matsushita, Hideki, Michizono, Shinichiro, Miura, Takako, Miyajima, Tsukasa, Nagahashi, Shinya, Nagai, Ryoji, Nakai, Hirotaka, Nakajima, Hiromitsu, Nakamura, Norio, Nakanishi, Kota, Nigorikawa, Kazuyuki, Nishimori, Nobuyuki, Nogami, Takashi, Noguchi, Shuichi, Obina, Takashi, Qiu, Feng, Sagehashi, Hidenori, Sakai, Hiroshi, Sakanaka, Shogo, Sasaki, Shinichi, Satoh, Kotaro, Sawamura, Masaru, Shimada, Miho, Shinoe, Kenji, Shishido, Toshio, Tadano, Mikito, Takahashi, Takeshi, Takai, Ryota, Takenaka, Tateru, Tanimoto, Yasunori, Uchiyama, Takashi, Ueda, Akira, Umemori, Kensei, Watanabe, Ken, and Yamamoto, Masahiro

Published
2018
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15. Involvement of a gut–retina axis in protection against dietary glycemia-induced age-related macular degeneration

Author

Rowan, Sheldon, Jiang, Shuhong, Korem, Tal, Szymanski, Jedrzej, Chang, Min-Lee, Szelog, Jason, Cassalman, Christa, Dasuri, Kalavathi, McGuire, Christina, Nagai, Ryoji, Du, Xue-Liang, Brownlee, Michael, Rabbani, Naila, Thornalley, Paul J., Baleja, James D., Deik, Amy A., Pierce, Kerry A., Scott, Justin M., Clish, Clary B., Smith, Donald E., Weinberger, Adina, Avnit-Sagi, Tali, Lotan-Pompan, Maya, Segal, Eran, and Taylor, Allen

Published
2017

20. RAGE activation in macrophages and development of experimental diabetic polyneuropathy

Author

Osonoi, Sho, primary, Mizukami, Hiroki, additional, Takeuchi, Yuki, additional, Sugawa, Hikari, additional, Ogasawara, Saori, additional, Takaku, Shizuka, additional, Sasaki, Takanori, additional, Kudoh, Kazuhiro, additional, Ito, Koichi, additional, Sango, Kazunori, additional, Nagai, Ryoji, additional, Yamamoto, Yasuhiko, additional, Daimon, Makoto, additional, Yamamoto, Hiroshi, additional, and Yagihashi, Soroku, additional

Published
2022
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34. Anti-Diabetic Activity of Soymilk Yogurt and Identification of Inhibitory Compounds on the Formation of Advanced Glycation End-Products

Author

Nakashima, Yuki, primary, Yamamoto, Naoki, additional, Tsukioka, Ryosuke, additional, Sugawa, Hikari, additional, Ohshima, Rina, additional, Aoki, Kaede, additional, Hibi, Tomoyuki, additional, Onuki, Kotone, additional, Fukuchi, Yudai, additional, Yasuda, Shin, additional, Nagai, Ryoji, additional, and Kinoshita, Hideki, additional

Published
2022
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37. Trapa bispinosa Roxb. and lutein ameliorate cataract in type 1 diabetic rats

Author

Kinoshita, Sho, Sugawa, Hikari, Nanri, Tomoaki, Ohno, Rei-ichi, Shirakawa, Jun-ichi, Sato, Hikari, Katsuta, Nana, Sakake, Shiori, and Nagai, Ryoji

Subjects
oxidation, cataract, advanced glycation end products, diabetes mellitus, food and beverages, Original Article, Trapa bispinosa Roxb
Abstract

Trapa bispinosa Roxb. is an annual aquatic grass of the citrus family. Although its hot water extract displays antioxidative activity in vitro, little is known about its biological effectiveness. In the present study, we evaluated the extract’s inhibitory effect on diabetic cataractogenesis and formation of advanced glycation end-product. Lutein, which is beneficial for eye diseases, was administered concurrently. For short-term administration, Trapa bispinosa Roxb. hot water extract and/or lutein were administered to type 1 diabetic rats. Nɛ-(carboxymethyl)lysine and Nɛ-(carboxyethyl)lysine were quantified in serum using mass spectrometry. The long-term administration study was similar to the short-term, except that the dosages were lower. In the short-term study, co-administration of the extract and lutein inhibited Nɛ-(carboxymethyl)lysine and Nɛ-(carboxyethyl)lysine in serum. However, in the long-term study, only lutein inhibited Nɛ-(carboxymethyl)lysine and Nɛ-(carboxyethyl)lysine in serum. These results suggest that lutein exerts its long-term effect regardless of the concentration administered, while the extract exerts its effect when its concentration is increased. Relative to the consumption of the control diet, oral intake of the combination of the extract and lutein significantly inhibited the progression of cataractogenesis in the lens of diabetic rats, even at low doses, and the combination was more effective than individual treatments.

Published
2019

46. Glyoxalase I overexpression ameliorates renal ischemia-reperfusion injury in rats

Author

Kumagai, Takanori, Nangaku, Masaomi, Kojima, Ichiro, Nagai, Ryoji, Ingelfinger, Julie R., Miyata, Toshio, Fujita, Toshiro, and Inagi, Reiko

Subjects
Acute renal failure -- Risk factors, Acute renal failure -- Genetic aspects, Acute renal failure -- Research, Gene expression -- Physiological aspects, Oxidative stress -- Complications and side effects, Biological sciences
Abstract

Methylglyoxal (MG), a highly reactive carbonyl compound generated by carbohydrate oxidation and glycolysis, is the major precursor of protein glycation and induces cytotoxicity leading to apoptosis. Although recent studies have emphasized that MG accumulates in not only chronic oxidative stress-related diseases but also acute hypoxic conditions, the pathogenic contribution of MG in acute diseases is unclear. MG is efficiently metabolized by the glyoxalase system, namely, glyoxalase I. We investigated the pathophysiological role of glyoxalase I as an MG detoxifier in rat renal ischemia-reperfusion (I/R) injury. I/R-induced tubulointerstitial injury was associated with a deterioration in renal glyoxalase I activity independent of its cofactor, GSH, as well as an increase in renal MG level. In in vitro studies, knockdown of glyoxalase I by small interference RNA transfection in rat tubular cells exacerbated cell death by hypoxia-reoxygenation compared with control cells. We also examined whether glyoxalase I overexpression prevented renal I/R damage in rats overexpressing human glyoxalase I with enzyme activity in the kidney 17-fold higher than in wild-type. The histological and functional manifestations of I/R in these rats were significantly ameliorated in association with a decrease in intracellular MG adduct accumulation, oxidative stress, and tubular cell apoptosis. In conclusion, glyoxalase I exerts renoprotective effects in renal I/R injury via a reduction in MG accumulation in tubular cells. acute renal failure; advanced glycation end products; methylglyoxal; oxidative stress; tubular cells

Published
2009

47. CD36 is one of important receptors promoting renal tubular injury by advanced oxidation protein products

Author

Iwao, Yasunori, Nakajou, Keisuke, Nagai, Ryoji, Kitamura, Kenichiro, Anraku, Makoto, Maruyama, Toru, and Otagiri, Masaki

Subjects
Cell receptors -- Physiological aspects, Kidney diseases -- Risk factors, Kidney diseases -- Research, Serum albumin -- Physiological aspects, Biological sciences
Abstract

Chronic accumulation of plasma advanced oxidation protein products (AOPPs) promotes renal fibrosis. However, the mechanism at the cellular level has not been clarified. In the present study, endocytic assay of human proximal tubular cells (HK-2 cells) demonstrated that AOPPs-human serum albumin (HSA) (in vitro preparations of chloramine-modified HSA) were significantly endocytosed in a dose-dependent manner at a higher level than HSA. The expression of CD36, a transmembrane protein of the class B scavenger receptor, in HK-2 cells was confirmed in the immunoblot analysis. In a cellular assay using overexpressing human CD36 in Chinese hamster ovary (CHO) cells, AOPPs-HSA were significantly endocytosed by CD36-CHO cells but not by mock-CHO cells. Furthermore, the endocytic association and degradation of AOPPs-HSA by HK-2 cells was significantly inhibited by anti-CD36 antibody treatment, suggesting that CD36 is partly involved in the uptake of AOPPs-HSA by HK-2 cells. AOPPs-HSA upregulated the expression of CD36 in a dose-dependent manner. In addition, AOPPs-HSA upregulated the generation of intracellular reactive oxygen species and the secretion of transforming growth factor (TGF)-[beta]1 in HK-2 cells, whereas anti-CD36 antibody neutralizes the upregulation of TGF-[beta]1. These results suggest that AOPPs-HSA may cause renal tubular injury via the CD36 pathway. endocytosis; transforming growth factor-[beta]1

Published
2008

48. Research and Development of Attosecond VUV and X-ray Sources Driven by Mid-Infrared FEL Oscillators

Author

Hajima, Ryoichi, Nagai, Ryoji, Kawase, Keigo, Ohgaki, Hideaki, Zen, Heishun, Hayakawa, Yasushi, Sakai, Takeshi, Sumitomo, Yosuke, Shimada, Miho, Miyajima, Tsukasa, Ryoichi, Hajima, Ryoji, Nagai, and Keigo, Kawase

Abstract

A research program towards an attosecond photon source based on high-harmonic generation driven by mid-infrared FEL oscillators has been established. We present the scope and the current status of the research program., High-brightness Sources and Light-driven Interactions Congress

Published
2020

49. 差周波中赤外光源のためのファイバーレーザーの開発

Author

Kawase, Keigo, Hajima, Ryoichi, and Nagai, Ryoji

Abstract

Q-LEAP基礎基盤研究の課題としてQST、京大、日大、KEKで進めている中赤外FELによるHHGのための基礎研究において、FELのCEPを安定化するためのCEP安定中赤外シード光源を開発している。この光源は、繰り返し20 MHz程度で数10 mW程度のCEP安定化光源を想定しており、現在、Ybファイバーレーザーによる差周波発生光源を設計・構築している。これまでに20 MHzのモードロック発振器、3 W級のプリアンプ、10 W超のアンプの構築し、現在、差周波発生のための波長シフト光発生試験および差周波発生光学系の設計を実施している。本発表では、このレーザーシステム開発についての現状を報告する。, 第17回日本加速器学会年会

Published
2020

50. 赤外 FEL シード用ファイバーレーザーシステムの開発

Author

Kawase, Keigo, Hajima, Ryoichi, and Nagai, Ryoji

Abstract

赤外自由電子レーザー(FEL)によるアト秒 X 線光源のための基礎研究として、赤外 FEL のキャリアエンベロープ位相(CEP)を制御するためのCEP 安定化シード光源であるファイバーレーザーを基礎とした差周波中赤外光源の開発について報告する。, 日本物理学会第75回年次大会

Published
2020

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