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1,763 results on '"Yamada, Takumi"'

154. Effect of Simultaneous Dual-Task Training on Regional Cerebral Blood Flow in Older Adults with Amnestic Mild Cognitive Impairment

Author

Kunieda, Yota, Arakawa, Chiaki, Yamada, Takumi, Koyama, Shingo, Suzuki, Mizue, Ishiyama, Daisuke, Yamada, Minoru, Hirokawa, Ryuto, Matsuda, Tadamitsu, Nio, Shintaro, Adachi, Tomohide, Hoshino, Haruhiko, and Fujiwara, Toshiyuki

Abstract

Background: No previous study has examined the effect of dual-task training using changes in regional cerebral blood flow (rCBF) using single-photon emission computed tomography (SPECT) as an outcome. Objective: This study aimed to examine the effects of simultaneous dual-task training of exercise and cognitive tasks on rCBF using SPECT in older adults with amnestic mild cognitive impairment (aMCI). Methods: In this non-randomized control trial, 40 older adults with aMCI participated from May 2016 to April 2018. Outpatients in the intervention group (n = 22) underwent 24 sessions (12 months) of dualtask training twice a month for 60 mins per session. Participants in the control group (n = 18) continued to have regular outpatient visits. The primary outcome was rCBF at baseline and after 12 months, which was compared in each group using the two-sample t-test. The secondary outcomes were the rate of reversion and conversion from aMCI after 12 months. Results: Of the 22 participants in the intervention group, six dropped out; therefore, 16 were included in the analysis. The intervention group showed more significant increases in rCBF in multiple regions, including the bilateral frontal lobes, compared with the control group. However, the rates of reversion or conversion from mild cognitive impairment (MCI) were not significantly different. Conclusion: Dual-task training for older adults with aMCI increased rCBF in the frontal gyrus but did not promote reversion from MCI to normal cognition. Future intervention studies, such as follow-up examinations after the intervention, are warranted to consider long-term prognosis.

Published
2023
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158. Characteristics of Regional Cerebral Blood Flow in Alzheimer Disease and Amnestic Mild Cognitive Impairment by Single-Photon Emission Computerized Tomography: A Cross-Sectional Study

Author

Kunieda, Yota, primary, Arakawa, Chiaki, additional, Yamada, Takumi, additional, Suzuki, Mizue, additional, Koyama, Shingo, additional, Kimura, Yosuke, additional, Ichikawa, Takeo, additional, Shino, Shuhei, additional, Yamada, Minoru, additional, Hirokawa, Ryuto, additional, Matsuda, Tadamitsu, additional, Takakura, Tomokazu, additional, Adachi, Tomohide, additional, and Hoshino, Haruhiko, additional

Published
2021
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159. LiNbO3‐Type Polar Antiferromagnet InVO3 Synthesized under High‐Pressure Conditions.

Author

Tan, Zhenhong, Lussier, Joey A., Yamada, Takumi, Xu, Yuanhui, Saito, Takashi, Goto, Masato, Kosugi, Yoshihisa, Vrublevskiy, Dmitry, Kanemitsu, Yoshihiko, Bieringer, Mario, and Shimakawa, Yuichi

Abstract

The ambient pressure cation disordered InVO3 bixbyite has been predicted to form a GdFeO3‐type perovskite phase under high pressure and high temperature. Contrary to the expectation, InVO3 was found to crystallize in the polar LiNbO3‐type structure with a calculated spontaneous polarization as large as 74 μC cm−2. Antiferromagnetic coupling of V3+ magnetic moments and a cooperative magnetic ground state below about 10 K coupled with a polar structure suggest an intriguing ground state of the novel LiNbO3‐type high‐pressure InVO3 structure. [ABSTRACT FROM AUTHOR]

Published
2022
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171. Effect of setup error in the single-isocenter technique on stereotactic radiosurgery for multiple brain metastases

Author

Nakano, Hisashi, Tanabe, Satoshi, Utsunomiya, Satoru, Yamada, Takumi, Sasamoto, Ryuta, Nakano, Toshimichi, Saito, Hirotake, Takizawa, Takeshi, Sakai, Hironori, Ohta, Atsushi, Abe, Eisuke, Kaidu, Motoki, 1000080360915, Aoyama, Hidefumi, Nakano, Hisashi, Tanabe, Satoshi, Utsunomiya, Satoru, Yamada, Takumi, Sasamoto, Ryuta, Nakano, Toshimichi, Saito, Hirotake, Takizawa, Takeshi, Sakai, Hironori, Ohta, Atsushi, Abe, Eisuke, Kaidu, Motoki, 1000080360915, and Aoyama, Hidefumi

Abstract

In conventional stereotactic radiosurgery (SRS), treatment of multiple brain metastases using multiple isocenters is time-consuming resulting in long dose delivery times for patients. A single-isocenter technique has been developed which enables the simultaneous irradiation of multiple targets at one isocenter. This technique requires accurate positioning of the patient to ensure optimal dose coverage. We evaluated the effect of six degrees of freedom (6DoF) setup errors in patient setups on SRS dose distributions for multiple brain metastases using a single-isocenter technique. We used simulated spherical gross tumor volumes (GTVs) with diameters ranging from 1.0 to 3.0 cm. The distance from the isocenter to the target's center was varied from 0 to 15 cm. We created dose distributions so that each target was entirely covered by 100% of the prescribed dose. The target's position vectors were rotated from 0 degrees-2.0 degrees and translated from 0-1.0 mm with respect to the three axes in space. The reduction in dose coverage for the targets for each setup error was calculated and compared with zero setup error. The calculated margins for the GTV necessary to satisfy the tolerance values for loss of GTV coverage of 3% to 10% were defined as coverage-based margins. In addition, the maximum isocenter to target distance for different 6DoF setup errors was calculated to satisfy the tolerance values. The dose coverage reduction and coverage-based margins increased as the target diameter decreased, and the distance and 6DoF setup error increased. An increase in setup error when a single-isocenter technique is used may increase the risk of missing the tumor; this risk increases with increasing distance from the isocenter and decreasing tumor size.

Published
2020

175. Detecting MLC modeling errors using radiomics‐based machine learning in patient‐specific QA with an EPID for intensity‐modulated radiation therapy

Author

Sakai, Madoka, primary, Nakano, Hisashi, additional, Kawahara, Daisuke, additional, Tanabe, Satoshi, additional, Takizawa, Takeshi, additional, Narita, Akihiro, additional, Yamada, Takumi, additional, Sakai, Hironori, additional, Ueda, Masataka, additional, Sasamoto, Ryuta, additional, Kaidu, Motoki, additional, Aoyama, Hidefumi, additional, Ishikawa, Hiroyuki, additional, and Utsunomiya, Satoru, additional

Published
2021
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189. Exciton–Phonon and Trion–Phonon Couplings Revealed by Photoluminescence Spectroscopy of Single CsPbBr3Perovskite Nanocrystals

Author

Cho, Kenichi, Tahara, Hirokazu, Yamada, Takumi, Suzuura, Hidekatsu, Tadano, Terumasa, Sato, Ryota, Saruyama, Masaki, Hirori, Hideki, Teranishi, Toshiharu, and Kanemitsu, Yoshihiko

Abstract

Lead halide perovskite nanocrystals (NCs) have outstanding photoluminescence (PL) properties and excellent potential for light-emitting diodes and single-photon sources. Here, we report the multiple-peak structures originating from excitons, trions, and biexcitons in low-temperature PL spectra of single CsPbBr3NCs. We found fine-structure splitting in the PL peaks of bright excitons and biexcitons and also in the longitudinal–optical (LO)-phonon replicas of excitons. LO-phonon replicas of trions are clearly observed under strong photoexcitation, which do not show fine-structure splitting. From size-dependent analyses of these replicas, we clarified that both exciton–phonon and trion–phonon couplings become larger for smaller NCs and the coupling strengths of trions are larger than those of excitons in large NCs. These behaviors can be explained by the spatial distributions of the electron and hole wave functions in the NCs. Our findings provide essential information on electron–phonon couplings in perovskites and for the design of high-purity single-photon sources.

Published
2022
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191. A Combined Therapy Using Encircling Pulmonary Vein Isolation and Supplemental Segmental Ostial Isolation for the Treatment of Atrial Fibrillation

Author

Tsuboi, Naoya, Yoshida, Yukihiko, Masaya, Matsumoto, Yamamoto, Takashi, Aoyama, Yutaka, Ishikawa, Makoto, Ogura, Yasuhiro, Suzuki, Hirohiko, Yamashita, Kentaro, Muramatsu, Takashi, Nanasato, Mamoru, Hirayama, Haruo, Itoh, Teruo, Okada, Taro, Yamada, Takumi, Murakami, Yoshimasa, Kondo, Takahisa, Inden, Yasuya, Murohara, Toyoaki, Kodama, Itsuo, and Toyama, Junji

Published
2006
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192. Electrophysiological pulmonary vein antrum isolation with a multielectrode basket catheter is feasible and effective for curing paroxysmal atrial fibrillation: Efficacy of minimally extensive pulmonary vein isolation

Author

Yamada, Takumi, Murakami, Yoshimasa, Okada, Taro, Okamoto, Mitsuhiro, Shimizu, Takeshi, Toyama, Junji, Yoshida, Yukihiko, Tsuboi, Naoya, Ito, Teruo, Muto, Masahiro, Kondo, Takahisa, Inden, Yasuya, Hirai, Makoto, and Murohara, Toyoaki

Published
2006
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