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529 results on '"Hara, Daisuke"'

9. $Z_2$ Dirac points with topologically protected multihelicoid surface states

Author

Zhang, Tiantian, Hara, Daisuke, and Murakami, Shuichi

Subjects
Condensed Matter - Materials Science
Abstract

In some Dirac systems with time-reversal (T) and glide (G) symmetries, multihelicoid surface states (MHSSs) appear, as discussed in various systems such as electronic and photonic ones. However, the topological nature and the conditions for the appearance of the MHSSs have not been understood. Here we show that MHSSs result from bulk-surface correspondence for the $Z_2$ monopole charge Q, which cannot be defined as a local quantity associated with the Dirac point, unlike the Z monopole charge characterizing Weyl points. The previously known formula of Q turns out to be non-gauge-invariant and thus cannot characterize the MHSSs. This shortcoming of the definition of Q is amended by redefining Q as a global topological invariant in k-space. Surprisingly, the newly defined Q, characterizing GT invariant gapless systems, is equal to the G-protected $Z_2$ topological invariant v, which is nontrivial only in T-breaking gapped systems. This global definition of Q automatically guarantees the appearance of MHSSs even when the Dirac point splits into Weyl points or a nodal ring by lowering the symmetry, as long as the GT symmetry is preserved. Q can be simplified to symmetry-based indicators when two vertical Gs are preserved, and filling-enforced topological crystalline insulators are diagnosed in several cases when a T-breaking perturbation is induced. Material candidate Li2B4O7 together with a list of space groups preserving MHSSs are also proposed., Comment: 10 pages, 5 figures, 1 table

Published
2022
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12. Unique surface-state connection between Weyl and nodal ring fermions in ferromagnetic material Cs2MoCl6

Author

Zhang, Tiantian, Hara, Daisuke, and Murakami, Shuichi

Subjects
Condensed Matter - Materials Science, Physics - Computational Physics
Abstract

For topological materials with coexistence of Weyl nodes and nodal rings, the surface-state configuration and connection are unique yet have never been studied and discussed before. In this paper, we predict a ferromagnetic (FM) material, Cs2MoCl6, with coexistence of Weyl and nodering fermions in its spinful FM electronic band structure, which is unusual since FM materials are very rare in nature and node-ring band crossings will usually open a gap when spin-orbit coupling (SOC) is taken into consideration. We find that the surface states of Cs2MoCl6 show different properties along different directions, i.e, the surface states are in the drumhead shape showing the node-ring property on the (001) surface and in the helicoid shape showing the Weyl property on the (010) surface. Interestingly, both the drumhead surface states and the helicoid surface states will cross the projected points of the Weyl and nodal ring along different directions. In particular, helicoid surface states on the (010) surface will meet the nodal ring tangentially, with their shapes change abruptly as a function of the energy. We implement both first-principle calculation and an analytical model to understand the unique surface-state connection for systems with the coexistence of Weyl nodes and nodal rings (or nodal lines). This result is universal and irrespective of the presence/absence of and time-reversal symmetry (T)., Comment: 6 pages, 4 figures

Published
2021
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27. Factors affecting patient satisfaction related to cost and treatment effectiveness in rheumatoid arthritis: results from the multicenter observational cohort study, FRANK Registry

Author

Fujiwara, Toshifumi, Kondo, Masakazu, Yamada, Hisakata, Haraguchi, Akihisa, Fujimura, Kenjiro, Sakuraba, Koji, Kamura, Satoshi, Fukushi, Jun-ichi, Miyahara, Hisaaki, Inoue, Yasushi, Tsuru, Tomomi, Shuto, Toshihide, Yoshizawa, Seiji, Suematsu, Eiichi, Miyamura, Tomoya, Ayano, Masahiro, Mitoma, Hiroki, Arinobu, Yojiro, Niiro, Hiroaki, Ohishi, Masanobu, Hirata, Akie, Tokunaga, Shoji, Takada, Atsushi, Hara, Daisuke, Tsushima, Hidetoshi, Akasaki, Yukio, Ikemura, Satoshi, Sueishi, Takuya, Toya, Masakazu, Sakuragi, Takahide, Tsutsui, Tomoko, Kai, Kazuhiro, Arisumi, Shinkichi, and Nakashima, Yasuharu

Published
2022
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29. Risk factor analysis of vertebral fractures requiring surgery in patients with ankylosing spondylitis

Author

Kai, Kazuhiro, primary, Fujiwara, Toshifumi, additional, Akasaki, Yukio, additional, Tsushima, Hidetoshi, additional, Hara, Daisuke, additional, Arisumi, Shinkichi, additional, Tsurui, Ryosuke, additional, Yasumoto, Keitaro, additional, Saiwai, Hirokazu, additional, Kawaguchi, Kenichi, additional, Yamada, Hisakata, additional, and Nakashima, Yasuharu, additional

Published
2024
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30. PP2A negatively regulates NK cell T-bet expression and anti-tumor effector function.

Author

Shinzawa, Yui, Hara, Daisuke, Shinguryo, Yuki, Yokoyama, Satoru, Kawada, Manabu, and Hayakawa, Yoshihiro

Subjects
*KILLER cells, *IMMUNE response, *MTOR protein, *PHOSPHOPROTEIN phosphatases, *RIBOSOMAL proteins
Abstract

The transcription factor T-bet is essential for the anti-tumor effector function of natural killer (NK) cells, but the mechanism regulating its expression in NK cells remains unclear. In this study, we aimed to identify an NK cell-intrinsic regulator that controls T-bet expression. Using T-bet-luciferase reporter assay screening, we identified a protein phosphatase inhibitor as a potential activator of T-bet expression. A series of protein phosphatase 2A (PP2A)-specific inhibitors (PP2Ai) or PP2A siRNA induced the expression of T-bet. In PP2Ai-treated mice, the expression of T-bet and its downstream effector molecules, granzyme B and IFN-γ, was also upregulated in NK cells. Mechanistically, PP2Ai increased the phosphorylation of mTOR and ribosomal protein S6 in NK cells, and mTOR inhibitor canceled the effects of PP2Ai in NK cells. Importantly, NK cells isolated from PP2Ai-treated mice showed higher cytotoxicity and IFN-γ production; therefore, they increased the anti-tumor effector function of NK cells. Accordingly, PP2Ai treatment inhibited lung metastasis of B16 melanoma by NK cell- and mTOR-dependent mechanisms. These results suggest that PP2A negatively regulates NK cell T-bet expression and effector function by an mTOR-dependent mechanism. [ABSTRACT FROM AUTHOR]

Published
2025
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33. Constructing a Highly Accurate Japanese Sign Language Motion Database Including Dialogue

Author

Nagashima, Yuji, Watanabe, Keiko, Hara, Daisuke, Horiuchi, Yasuo, Sako, Shinji, Ichikawa, Akira, Filipe, Joaquim, Editorial Board Member, Ghosh, Ashish, Editorial Board Member, Kotenko, Igor, Editorial Board Member, Prates, Raquel Oliveira, Editorial Board Member, Zhou, Lizhu, Editorial Board Member, Stephanidis, Constantine, editor, and Antona, Margherita, editor

Published
2020
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34. Perilymphatic enhancement and endolymphatic hydrops: MRI findings and clinical associations.

Author

Kobayashi, Masumi, Yoshida, Tadao, Fukunaga, Yukari, Hara, Daisuke, Naganawa, Shinji, and Sone, Michihiko

Subjects
MENIERE'S disease, SENSORINEURAL hearing loss, EAR diseases, MAGNETIC resonance imaging, HEARING levels, INNER ear, EAR
Abstract

Objective: In this study, we aimed to summarize magnetic resonance imaging (MRI) findings of perilymphatic enhancement (PE) and endolymphatic hydrops (EH) of the inner ear, which are associated with vestibular and cochlear symptoms. Methods: We analyzed data on ears with definite Meniere's disease (MD), sensorineural hearing loss (SNHL), vertigo, and listening difficulties (LiD) from 508 ears of 254 patients who underwent contrast‐enhanced 3‐Tesla MRI between April 2021 and March 2023. We evaluated the degree of endolymphatic hydrops (EH), signal intensity ratios (SIRs) between the basal turns of the cochlea and cerebellum, and hearing levels for all ears. Ears with definite MD were also assessed for changes in vestibular and cochlear symptoms within 6 months. Results: Ears with definite MD exhibited significantly higher percentages of EH in both the vestibule and cochlea compared with ears with other diseases. Furthermore, ears with MD or sensorineural hearing loss (SNHL) had significantly higher SIRs of PE compared with ears with other diseases or asymptomatic ears. Among patients with definite MD, those experiencing hearing fluctuations or vertigo attacks within the last 6 months had significantly higher SIRs of PE compared with those who did not experience any symptoms. Conclusion: Significant EH in the vestibule and cochlea was a major finding for the imaging diagnosis of definite MD. A high SIR of PE was a good indicator for assessing MD activity, reflecting vestibular and cochlear symptoms and fluctuations. Level of Evidence: 4. [ABSTRACT FROM AUTHOR]

Published
2024
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38. Presence of endolymphatic hydrops on listening difficulties in patients with normal hearing level

Author

Yoshida, Tadao, Kobayashi, Masumi, Sugimoto, Satofumi, Fukunaga, Yukari, Hara, Daisuke, Naganawa, Shinji, Sone, Michihiko, Yoshida, Tadao, Kobayashi, Masumi, Sugimoto, Satofumi, Fukunaga, Yukari, Hara, Daisuke, Naganawa, Shinji, and Sone, Michihiko

Abstract

Background: Listening difficulties (LiD) present difficulties in listening and paying attention to spoken information despite normal pure tone audiometry. Endolymphatic hydrops (EH) is a common inner ear condition associated with Ménière’s disease but may also be present in the asymptomatic ear. Objectives: Using magnetic resonance imaging, we investigated EH in patients with LiD and assessed whether the severity of EH was related to the results of auditory processing tests (APTs). Materials and Methods: 111 patients with no abnormalities on pure tone audiometry, but displaying difficulties in listening, underwent evaluation through APTs and questionnaires. Upon obtaining informed consent, the inner ears of 20 consenting patients were evaluated utilizing a 3-Tesla magnetic resonance imaging. Results: A higher percentage of patients diagnosed with LiD by APTs had significant EH in the cochlea and vestibule than in previously reported control cases. The percentage of correct answers in the speech-in-noise test was significantly lower in patients with than in those without significant EH. Conclusion and significance: In this study, significant EH of the cochlea was associated with poor listening to noise. The presence of EH affects the functioning of the auditory processing system, even in ears that test normally on standard audiometric tests.

Published
2024

39. Construction of a Japanese Sign Language Database with Various Data Types

Author

Watanabe, Keiko, Nagashima, Yuji, Hara, Daisuke, Horiuchi, Yasuo, Sako, Shinji, Ichikawa, Akira, Barbosa, Simone Diniz Junqueira, Editorial Board Member, Filipe, Joaquim, Editorial Board Member, Ghosh, Ashish, Editorial Board Member, Kotenko, Igor, Editorial Board Member, Yuan, Junsong, Editorial Board Member, Zhou, Lizhu, Editorial Board Member, and Stephanidis, Constantine, editor

Published
2019
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42. Synovial-tissue resident macrophages play proinflammatory functions in the pathogenesis of RA while maintaining the phenotypes in the steady state

Author

Kai, Kazuhiro, primary, Yamada, Hisakata, additional, Tsurui, Ryosuke, additional, Sakuraba, Koji, additional, Fujimura, Kenjiro, additional, Kawahara, Shinya, additional, Akasaki, Yukio, additional, Tsushima, Hidetoshi, additional, Fujiwara, Toshifumi, additional, Hara, Daisuke, additional, Fukushi, Jun-ichi, additional, Sawa, Shinichiro, additional, and Nakashima, Yasuharu, additional

Published
2024
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