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1,692 results on '"Seki, Shu"'

154. TAKOTSUBO SYNDROME IN OCTOGENARIANS AND NONAGENARIANS

Author

Nishimura, Yuki, primary, Fujita, Takako, additional, Komatsu, Junya, additional, Kubokawa, Sho-ichi, additional, Imai, Ryu-ichiro, additional, Nakaoka, Yoko, additional, Nishida, Koji, additional, Yamamoto, Satoshi, additional, Seki, Shu-ichi, additional, Kawai, Kazuya, additional, Hamasige, Naohisa, additional, and Doi, Yoshinori L., additional

Published
2020
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155. KAWASAKI DISEASE: ACUTE MYOCARDIAL INFARCTION OF ADULT-ONSET ASSOCIATED WITH A GIANT CORONARY ARTERY ANEURYSM

Author

Nakayama, Yuji, primary, Komatsu, Junya, additional, Nishimura, Yuki, additional, Fujita, Takako, additional, Kida, Ryota, additional, Imai, Ryu-ichiro, additional, Nakaoka, Yoko, additional, Nishida, Koji, additional, Yamamoto, Satoshi, additional, Seki, Shu-ichi, additional, Kubokawa, Sho-ichi, additional, Ikebuchi, Masahiko, additional, Irie, Hiroyuki, additional, Kawai, Kazuya, additional, Hamashige, Naohisa, additional, and Doi, Yoshinori L., additional

Published
2020
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159. Protein-directed crystalline 2D fullerene assemblies

Author

Liutkus, Mantas, primary, López-Andarias, Alicia, additional, Mejías, Sara H., additional, López-Andarias, Javier, additional, Gil-Carton, David, additional, Feixas, Ferran, additional, Osuna, Sílvia, additional, Matsuda, Wakana, additional, Sakurai, Tsuneaki, additional, Seki, Shu, additional, Atienza, Carmen, additional, Martín, Nazario, additional, and Cortajarena, Aitziber L., additional

Published
2020
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164. Helical Pore Alignment on Cylindrical Carbon

Author

Maruyama, Jun, primary, Shinagawa, Tsutomu, additional, Watanabe, Mitsuru, additional, Kashiwagi, Yukiyasu, additional, Maruyama, Shohei, additional, Nagaoka, Toru, additional, Matsuda, Wakana, additional, Tsutsui, Yusuke, additional, Seki, Shu, additional, and Uyama, Hiroshi, additional

Published
2019
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165. Ion beam induced crosslinking reactions in poly(di-n-hexylsilane)

Author

Seki, Shu, Maeda, Kensaku, Kunimi, Yoshihisa, Tagawa, Seiichi, Yoshida, Yoichi, Kudoh, Hisaaki, Sugimoto, Masaki, Morita, Yosuke, Seguchi, Tadao, Iwai, Takeo, Shibata, Hiromi, Asai, Keisuke, and Ishigure, Kenkichi

Subjects
Silane -- Research, Ion bombardment -- Usage, Crosslinked polymers -- Research, Chemicals, plastics and rubber industries
Abstract

Thin solid films of poly(di-n-hexylsilane) were irradiated with a number of high-energy ion beams, electron beams and 60Co gamma-rays of which linear energy transfer (LET) ranges from 0.2 to 1620 eV/nm. The beams induced nonhomogeneous reactions of crosslinking and main chain scissions in the films. A reaction model in a single ion track was applied for the crosslinking reactions. The expanding chemical track along an ion trajectory increased crosslinking G values.

Published
1999

168. A Supramolecular Polymer Constituted of Antiaromatic NiII Norcorroles.

Author

Ukai, Shusaku, Takamatsu, Aiko, Nobuoka, Masaki, Tsutsui, Yusuke, Fukui, Norihito, Ogi, Soichiro, Seki, Shu, Yamaguchi, Shigehiro, and Shinokubo, Hiroshi

Subjects
SUPRAMOLECULAR polymers, STACKING interactions, ELECTRONIC materials, ELECTRONIC structure, MONOMERS, PORPHYRINS
Abstract

For the creation of next‐generation organic electronic materials, the integration of π‐systems has recently become a central theme. Such functional materials can be assembled by supramolecular polymerization when aromatic π‐systems are used as monomers, and the properties of the resulting supramolecular polymer strongly depend on the electronic structure of the monomers. Here, we demonstrate the construction of a supramolecular polymer consisting of an antiaromatic π‐system as the monomer. An amide‐functionalized NiII norcorrole derivative formed a one‐dimensional supramolecular polymer through π‐π stacking and hydrogen‐bonding interactions, ensuring the persistency of the conducting pathway against thermal perturbation, which results in higher charge mobility along the tightly bound linear aggregates than that of the aromatic analogue composed of ZnII porphyrins. [ABSTRACT FROM AUTHOR]

Published
2022
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169. Stability of radicals in aryl-substituted polysilanes with linear and planar silicon skeleton structures

Author

Seki, Shu, Cromack, Keith R., Trifunac, Alexander D., Yoshida, Yoichi, Tagawa, Seiichi, Asai, Keisuke, and Ishigure, Kenkichi

Subjects
Silane -- Analysis, Radicals (Chemistry) -- Analysis, Chemical equilibrium -- Analysis, Chemicals, plastics and rubber industries
Abstract

The stability of silyl radicals in solid-state poly(methylphenylsilane) (PMPS), PMPS containing structural defects and poly(phenylsilane) (PPS) with a silicon skeleton network has been studied. PMPS and phenyl-substituted PPS were subjected to 60Co gamma rays in the solid state. Results indicate that neutral silyl radicals in solid aryl-substituted polysilanes were found to be weaker than radicals obtained from dimethyl-substituted polysilanes. The radicals are stabilized by the defect in the silicon skeleton and the highly-branched silyl radicals have excellent stability.

Published
1998

171. Repurposing DNA-binding agents as H-bonded organic semiconductors

Author

30273709, Zhang, Fengjiao, Lemaur, Vincent, Choi, Wookjin, Kafle, Prapti, Seki, Shu, Cornil, Jérôme, Beljonne, David, Diao, Ying, 30273709, Zhang, Fengjiao, Lemaur, Vincent, Choi, Wookjin, Kafle, Prapti, Seki, Shu, Cornil, Jérôme, Beljonne, David, and Diao, Ying

Published
2019

172. Observation of dissociative quasi-free electron attachment to nucleoside via excited anion radical in solution

Author

50632907, 30273709, Ma, Jun, Kumar, Anil, Muroya, Yusa, Yamashita, Shinichi, Sakurai, Tsuneaki, Denisov, Sergey A., Sevilla, Michael D., Adhikary, Amitava, Seki, Shu, Mostafavi, Mehran, 50632907, 30273709, Ma, Jun, Kumar, Anil, Muroya, Yusa, Yamashita, Shinichi, Sakurai, Tsuneaki, Denisov, Sergey A., Sevilla, Michael D., Adhikary, Amitava, Seki, Shu, and Mostafavi, Mehran

Abstract

Damage to DNA via dissociative electron attachment has been well-studied in both the gas and condensed phases; however, understanding this process in bulk solution at a fundamental level is still a challenge. Here, we use a picosecond pulse of a high energy electron beam to generate electrons in liquid diethylene glycol and observe the electron attachment dynamics to ribothymidine at different stages of electron relaxation. Our transient spectroscopic results reveal that the quasi-free electron with energy near the conduction band effectively attaches to ribothymidine leading to a new absorbing species that is characterized in the UV-visible region. This species exhibits a nearly concentration-independent decay with a time constant of ~350 ps. From time-resolved studies under different conditions, combined with data analysis and theoretical calculations, we assign this intermediate to an excited anion radical that undergoes N1-C1′ glycosidic bond dissociation rather than relaxation to its ground state.

Published
2019

175. Synthesis of terminus-decorated aza[9]helicenes: control of interlayer interaction

Author

Matsuo, Yusuke, Seki, Shu, and Tanaka, Takayuki

Abstract

Azahelicenes are intriguing luminescent materials with a planar chirality. The properties of aza[9]helicene can be perturbed by attaching substituent at the termini. The impact of the terminal decoration has been investigated in view of structural and electronic aspects, leading to the control of interlayer interaction.Graphical AbstractAzahelicenes are intriguing luminescent materials with a planar chirality. The properties of aza[9]helicene can be perturbed by attaching methoxy, 4-tert-butylphenyl, or 7-tert-butylpyrenyl substituents at the termini. The impact of the terminal decoration has been investigated in view of structural and electronic aspects, leading to the control of interlayer interaction.

Published
2024
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176. Regioisomer effects of [70]fullerene mono-adduct acceptors in bulk heterojunction polymer solar cells† †Electronic supplementary information (ESI) available. CCDC 1420203–1420205. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6sc02950g Click here for additional data file. Click here for additional data file. Click here for additional data file. Click here for additional data file

Author

Umeyama, Tomokazu, Miyata, Tetsushi, Jakowetz, Andreas C., Shibata, Sho, Kurotobi, Kei, Higashino, Tomohiro, Koganezawa, Tomoyuki, Tsujimoto, Masahiko, Gélinas, Simon, Matsuda, Wakana, Seki, Shu, Friend, Richard H., and Imahori, Hiroshi

Subjects
Chemistry, endocrine system diseases, integumentary system, digestive, oral, and skin physiology, digestive system, digestive system diseases
Abstract

Regioisomer separations of [70]fullerene mono-adducts for polymer solar cell (PSC) applications were conducted for the first time., Despite numerous organic semiconductors being developed during the past decade, C70 derivatives are predominantly used as electron acceptors in efficient polymer solar cells (PSCs). However, as-prepared C70 mono-adducts intrinsically comprise regioisomers that would mask individual device performances depending on the substituent position on C70. Herein, we separate the regioisomers of C70 mono-adducts for PSC applications for the first time. Systematic investigations of the substituent position effect using a novel symmetric C70 mono-adduct ([70]NCMA) and a prevalent, high-performance one ([70]PCBM) reveals that we can control the structures of the blend films with conjugated polymers and thereby improve the PSC performances by regioisomer separation. Our approach demonstrates the significance of exploring the best-matching regioisomer of C70 mono-adducts with high-performance conjugated polymers, which would achieve a remarkable progress in PSC devices.

Published
2016

177. Detailed Investigation of the Structural, Thermal, and Electronic Properties of Gold Isocyanide Complexes with Mechano-Triggered Single-Crystal-to-Single-Crystal Phase Transitions

Author

Seki, Tomohiro, Sakurada, Kenta, Muromoto, Mai, Seki, Shu, and Ito, Hajime

Subjects
gold complexes, photoluminescence, metal-metal interactions, single crystal, phase transitions
Abstract

Mechano-induced phase transitions in organic crystalline materials, which can alter their properties, have received much attention. However, most mechano-responsive molecular crystals exhibit crystal-to-amorphous phase transitions, and the intermolecular interaction patterns in the daughter phase are difficult to characterize. We have investigated phenyl(phenylisocyanide)gold(I) (1) and phenyl(3,5-dimethylphenylisocyanide)gold(I) (2) complexes, which exhibit a mechano-triggered single-crystal-to-single-crystal phase transition. Previous reports of complexes 1 and 2 have focused on the relationships between the crystalline structures and photoluminescence properties; in this work we have focused on other aspects. The face index measurements of complexes 1 and 2 before and after the mechano-induced phase transitions have indicated that they undergo non-epitaxial phase transitions without a rigorous orientational relationship between the mother and daughter phases. Differential scanning calorimetry analyses revealed the phase transition of complex 1 to be enthalpically driven by the formation of new aurophilic interactions. In contrast, the phase transition of complex 2 was found to be entropically driven, with the closure of an empty void in the mother phase. Scanning electron microscopy observation showed that the degree of the charging effect of both complexes 1 and 2 was changed by the phase transitions, which suggests that the formation of the aurophilic interactions affords more effective conductive pathways. Moreover, flash-photolysis time-resolved microwave conductivity measurements revealed that complex 1 increased in conductivity after the phase change, whereas the conductivity of complex 2 decreased. These contrasting results were explained by the different patterns in the aurophilic interactions. Finally, an intriguing disappearing polymorphism of complex 2 has been reported, in which a polymorph form could not be obtained again after some period of time, even with repeated trials. The present studies provide us with a variety of hitherto unknown insights into mechano-responsive molecular crystals, which help us to understand the phase transition behaviors upon mechanical stimulation and establish rational design principles.

Published
2016

182. Protein-Directed Crystalline 2D Fullerene Assemblies

Author

LIUTKUS, MANTAS, primary, López-Andarias, Alicia, primary, Mejías, Sara H., primary, López-Andarias, Javier, primary, Gil-Carton, David, primary, Feixas, Ferran, primary, Osuna, Sílvia, primary, Matsuda, Wakana, primary, Sakurai, Tsuneaki, primary, Seki, Shu, primary, Atienza, Carmen, primary, Martín, Nazario, primary, and Lopez Cortajarena, Aitziber, primary

Published
2019
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183. Systematic Synthesis of Tetrathia[8]circulenes: The Influence of Peripheral Substituents on the Structures and Properties in Solution and Solid States

Author

Kato, Shohei, primary, Akahori, Shuhei, additional, Serizawa, Yuma, additional, Lin, Xu, additional, Yamauchi, Mitsuaki, additional, Yagai, Shiki, additional, Sakurai, Tsuneaki, additional, Matsuda, Wakana, additional, Seki, Shu, additional, Shinokubo, Hiroshi, additional, and Miyake, Yoshihiro, additional

Published
2019
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185. Anomalous Photoinduced Hole Transport in Type I Core/Mesoporous-Shell Nanocrystals for Efficient Photocatalytic H2 Evolution

Author

Lian, Zichao, primary, Sakamoto, Masanori, additional, Kobayashi, Yoichi, additional, Tamai, Naoto, additional, Ma, Jun, additional, Sakurai, Tsuneaki, additional, Seki, Shu, additional, Nakagawa, Tatsuo, additional, Lai, Ming-Wei, additional, Haruta, Mitsutaka, additional, Kurata, Hiroki, additional, and Teranishi, Toshiharu, additional

Published
2019
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199. Fabrication of nanowires using high-energy ion beams

Author

Tsukuda, Satoshi, Seki, Shu, Tagawa, Seiichi, Sugimoto, Masaki, Tanaka, Shigeru, Idesaki, Akira, and Oshima, Akihiro

Subjects
Ions -- Atomic properties, Silicon -- Chemical properties, Chemicals, plastics and rubber industries
Abstract

Nanowire formation in Si-based polymer thin films using a heavy ion beam is discussed in terms of energy density deposition along ion tracks. Gelation of the polymer along the ion track results in cross-linking to produce nanowires with size and number density controllable by selecting appropriate ion beam characteristics and polymer materials

Published
2004

200. Structural influences on charge carrier dynamics for small-molecule organic photovoltaics.

Author

Zhiping Wang, Miyadera, Tetsuhiko, Saeki, Akinori, Ying Zhou, Seki, Shu, Shibata, Yosei, Yamanari, Toshihiro, Matsubara, Koji, and Yoshida, Yuji

Subjects
ZINC phthalocyanine, FULLERENES, CHARGE carriers, PHOTOVOLTAIC cells, ENERGY conversion, CRYSTAL grain boundaries
Abstract

We investigated the structural influences on the charge carrier dynamics in zinc phthalocyanine/ fullerene (ZnPc/C60) photovoltaic cells by introducing poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) and 2,5-bis(4-biphenylyl)-bithiophene (BP2T) between indium tin oxide and ZnPc layers. ZnPc films can be tuned to be round, long fiber-like, and short fiber-like structure, respectively. Time-resolved microwave conductivity measurements reveal that charge carrier lifetime in ZnPc/C60 bilayer films is considerably affected by the intra-grain properties. Transient photocurrent of ZnPc single films indicated that the charge carriers can transport for a longer distance in the long fiber-like grains than that in the round grains, due to the greatly lessened grain boundaries. By carefully controlling the structure of ZnPc films, the short-circuit current and fill factor of a ZnPc/C60 heterojunction solar cell with BP2T are significantly improved and the power conversion efficiency is increased to 2.6%, which is 120% larger than the conventional cell without BP2T. [ABSTRACT FROM AUTHOR]

Published
2014
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