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35 results on '"Nakai, Keita"'

1. Joint Universality for the Riemann zeta-function with general shifts

Author

Nakai, Keita

Subjects
Mathematics - Number Theory, 11M06
Abstract

Laurin\v{c}ikas proposed that whether the universality theorem for the Riemann zeta-function shifted by an exponential function holds or not. This problem is solved for more general shifts by Andersson et al. In this paper, we generalize their result for the joint universality theorem for the Riemann zeta-function with general shifts using a different approach from their method., Comment: 9 pages

Published
2023

2. Notes on Universality in Short Intervals and Exponential Shifts

Author

Andersson, Johan, Garunkštis, Ramūnas, Kačinskaitė, Roma, Nakai, Keita, Pańkowski, Łukasz, Sourmelidis, Athanasios, Steuding, Rasa, Steuding, Jörn, and Wananiyakul, Saeree

Subjects
Mathematics - Number Theory, 11M06
Abstract

We improve a recent universality theorem for the Riemann zeta-function in short intervals due to Antanas Laurin\v{c}ikas with respect to the length of these intervals. Moreover, we prove that the shifts can even have exponential growth. This research was initiated by two questions proposed by Laurin\v cikas in a problem session of a recent workshop on universality., Comment: 14 pages, 1 figure

Published
2023

3. Discrete universality for Matsumoto zeta-functions and the nontrivial zeros of the Riemann zeta-function

Author

Nakai, Keita

Subjects
Mathematics - Number Theory, 11M41
Abstract

In 2017, Garunk\v{s}tis, Laurin\v{c}ikas and Macaitien\.{e} proved the discrete universality theorem for the Riemann zeta-function sifted by the nontrivial zeros of the Riemann zeta-function. This discrete universality has been extended in various zeta-functions and $L$-functions. In this paper, we generalize this discrete universality for Matsumoto zeta-functions., Comment: 9 pages

Published
2023

6. Impact of Competition in Energy Market on Promotion of Renewables: An Agent-Based Model Approach

Author

Ogihara, Arashi, Suzuki, Kengo, Nakai, Keita, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Wardaszko, Marcin, editor, Meijer, Sebastiaan, editor, Lukosch, Heide, editor, Kanegae, Hidehiko, editor, Kriz, Willy Christian, editor, and Grzybowska-Brzezińska, Mariola, editor

Published
2021
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20. pH-Responsive Polyion Complex Vesicle with Polyphosphobetaine Shells

Author

Ohara, Yuki, Nakai, Keita, Ahmed, Sana, Matsumura, Kazuaki, Ishihara, Kazuhiko, and Yusa, Shin-ichi

Abstract

When a bioactive molecule is taken into cells by endocytosis, it is sometimes unable to escape from the lysosomes, resulting in inefficient drug release. We prepared pH-responsive polyion complex (PIC) vesicles that collapse under acidic conditions such as those inside a lysosome. Furthermore, under acidic conditions, cationic polymer was released from the PIC vesicles to break the lysosome membranes. Diblock copolymers (P20M167and P20A190) consisting of water-soluble zwitterionic poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) block and cationic or anionic blocks were synthesized via reversible addition–fragmentation chain transfer (RAFT) radical polymerization. Poly(3-(methacrylamidopropyl) trimethylammonium chloride) (PMAPTAC) and poly(sodium 6-acrylamidohexanoate) (PAaH) were used as the cationic and anionic blocks, respectively. The pendant hexanoate groups in the PAaH block are ionized in basic water and in phosphate buffered saline (PBS), while the hexanoate groups are protonated in acidic water. In basic water, PIC vesicles were formed from a charge neutralized mixture of oppositely charged diblock copolymers. At the interface of PIC vesicle and water exists biocompatible PMPC shells. Under acidic conditions, the PIC vesicles collapsed, because the charge balance shifted due to protonation of the PAaH block. After collapse of the PIC vesicles, P20A190formed micelles composed of protonated PAaH core and PMPC shells, while P20M167was released as unimers. PIC vesicles can encapsulate hydrophilic nonionic guest molecules into their hollow core. Under acidic conditions, the PIC vesicles can release the guest molecules and P20M167. The cationic P20M167can break the lysosome membrane to efficiently release the guest molecules from the lysosomes to the cytoplasm.

Published
2019
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23. Stable polymersomes based on ionic–zwitterionic block copolymers modified with superparamagnetic iron oxide nanoparticles for biomedical applications

Author

Kania, Gabriela, primary, Kwolek, Urszula, additional, Nakai, Keita, additional, Yusa, Shin-ichi, additional, Bednar, Jan, additional, Wójcik, Tomasz, additional, Chłopicki, Stefan, additional, Skórka, Tomasz, additional, Szuwarzyński, Michał, additional, Szczubiałka, Krzysztof, additional, Kepczynski, Mariusz, additional, and Nowakowska, Maria, additional

Published
2015
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28. Thermo-responsive liquid marbles

Author

Yusa, Shin-ichi, primary, Morihara, Masashi, additional, Nakai, Keita, additional, Fujii, Syuji, additional, Nakamura, Yoshinobu, additional, Maruyama, Atsushi, additional, and Shimada, Naohiko, additional

Published
2013
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32. Contribution of leg muscle strength to vertical jump

Author

KAI, YOSHIHIRO, primary, MURATA, SHIN, additional, SOMA, MASAYUKI, additional, TAMORI, MSYASUHIKO, additional, FUJITA, MIWAKO, additional, NAKAI, KEITA, additional, ISHIKAWA, HARUMI, additional, NAKAZAKI, CHIAKI, additional, and MADOBA, KATSUYUKI, additional

Published
2013
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