Details of the Researcher

PHOTO

Takuya Yokokita
Section
Research Center for Accelerator and Radioisotope Science
Job title
Assistant Professor
e-Rad No.
10802655

Research History 5

  • 2024/04 - Present
    Tohoku University

  • 2023/04 - 2024/03
    東北大学　電子光理学研究センター　助教

  • 2021/04 - 2023/03
    Salesian Polytechnic

  • 2018/04 - 2021/03
    RIKEN

  • 2017/04 - 2018/03
    国立研究開発法人理化学研究所　仁科加速器センター 応用研究開発室 RI応用チーム　特別研究員

Education 3

  • Osaka University　Graduate School of Science

    2012/04 - 2015/03

  • Osaka University　Graduate School of Science

    2010/04 - 2012/03

  • Kochi University

    2006/04 - 2010/03

Committee Memberships 3

  • 日本放射化学会　英文誌「Journal of Nuclear and Radiochemical Sciences」編集委員

    2024/04 - Present

  • 日本放射化学会　若手の会 世話人

    2023/04 - 2024/03

  • 日本放射化学会　核化学部会 幹事

    2022/07 - 2024/03

Professional Memberships 2

  • 日本放射化学会

  • 日本化学会

Research Interests 4

  • 分離化学

  • 超重元素

  • 核化学

  • 放射化学

Research Areas 1

  • Nanotechnology/Materials / Inorganic and coordination chemistry /

Papers 39

  1. Purification of a Au tracer from a Pt target using UTEVA resin column chromatography Peer-reviewed

    Takuya Yokokita, Yudai Shigekawa, Akihiro Nambu, Michiko Kitagawa, Hiromitsu Haba

    Journal of Chromatography A　467399-467399　2026/08

    Publisher: Elsevier BV

    DOI： 10.1016/j.chroma.2026.467399 　

    ISSN： 0021-9673

  2. Anion- and cation-exchange studies of Zr, Hf, and Th using ion-exchange resin and fiber in H2SO4 media for chemical characterization of sulfate complex of Rf Peer-reviewed

    Takuya Yokokita, Shinya Yano, Yukiko Komori, Hiromitsu Haba

    Journal of Radioanalytical and Nuclear Chemistry　331　(2)　1127-1134　2022/01/13

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1007/s10967-021-08184-y 　

    ISSN： 0236-5731

    eISSN： 1588-2780

  3. Co-precipitation behaviour of single atoms of rutherfordium in basic solutions Peer-reviewed

    Yoshitaka Kasamatsu, Keigo Toyomura, Hiromitsu Haba, Takuya Yokokita, Yudai Shigekawa, Aiko Kino, Yuki Yasuda, Yukiko Komori, Jumpei Kanaya, Minghui Huang, Masashi Murakami, Hidetoshi Kikunaga, Eisuke Watanabe, Takashi Yoshimura, Kosuke Morita, Toshiaki Mitsugashira, Koichi Takamiya, Tsutomu Ohtsuki, Atsushi Shinohara

    Nature Chemistry　13　(3)　226-230　2021/03

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1038/s41557-020-00634-6 　

    ISSN： 1755-4330

    eISSN： 1755-4349

  4. X-ray pumping of the 229Th nuclear clock isomer Peer-reviewed

    Takahiko Masuda, Akihiro Yoshimi, Akira Fujieda, Hiroyuki Fujimoto, Hiromitsu Haba, Hideaki Hara, Takahiro Hiraki, Hiroyuki Kaino, Yoshitaka Kasamatsu, Shinji Kitao, Kenji Konashi, Yuki Miyamoto, Koichi Okai, Sho Okubo, Noboru Sasao, Makoto Seto, Thorsten Schumm, Yudai Shigekawa, Kenta Suzuki, Simon Stellmer, Kenji Tamasaku, Satoshi Uetake, Makoto Watanabe, Tsukasa Watanabe, Yuki Yasuda, Atsushi Yamaguchi, Yoshitaka Yoda, Takuya Yokokita, Motohiko Yoshimura, Koji Yoshimura

    Nature　573　(7773)　238-242　2019/09/12

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1038/s41586-019-1542-3 　

    ISSN： 0028-0836

    eISSN： 1476-4687

  5. 104番元素Rfの抽出平衡の観測

    笠松良崇, 横北卓也

    放射化学　35　2-8　2017

  6. Observation of the chemical reaction equilibria of element 104, rutherfordium: solid–liquid extraction of Rf, Zr, Hf and Th with Aliquat 336 resin from HCl Peer-reviewed

    Takuya Yokokita, Yoshitaka Kasamatsu, Aiko Kino, Hiromitsu Haba, Yudai Shigekawa, Yuki Yasuda, Kouhei Nakamura, Keigo Toyomura, Yukiko Komori, Masashi Murakami, Takashi Yoshimura, Naruto Takahashi, Kosuke Morita, Atsushi Shinohara

    Dalton Transactions　45　(47)　18827-18831　2016

    Publisher: Royal Society of Chemistry (RSC)

    DOI： 10.1039/c6dt03497g 　

    ISSN： 1477-9226

    eISSN： 1477-9234

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    <p>We successfully observed the equilibrium state of the chemical reactions for superheavy element, Rf.</p>

  7. Distribution Behavior of Nb, Ta, and Pa as Homologues of Db in Cation Exchange and Solid-Liquid and Liquid-Liquid Extractions by Aliquat 336 from Hydrochloric Acid Peer-reviewed

    Takuya Yokokita, Yoshitaka Kasamatsu, Takashi Yoshimura, Naruto Takahashi, Atsushi Shinohara

    Solvent Extraction and Ion Exchange　33　(5)　472-495　2015/07/29

    Publisher: Informa UK Limited

    DOI： 10.1080/07366299.2015.1046297 　

    ISSN： 0736-6299

    eISSN： 1532-2262

  8. Solvent extraction using carrier-free radiotracers of Mo and W from HCl and HCl/LiCl solutions into Aliquat 336 Peer-reviewed

    T. Yokokita, K. Ooe, Y. Kasamatsu, T. Yoshimura, N. Takahashi, N. Shiohara, K. Takamiya, Y. Komori, Y. Kikutani, A. Kino, A. Shinohara

    Journal of Radioanalytical and Nuclear Chemistry　303　(2)　1091-1094　2015/02

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1007/s10967-014-3449-7 　

    ISSN： 0236-5731

    eISSN： 1588-2780

  9. Solvent extraction of Mo(V) and Mo(VI) from hydrochloric acid into Aliquat 336 chloroform solution Peer-reviewed

    T. Yokokita, Y. Kasamatsu, K. Ooe, T. Yoshimura, N. Takahashi, Y. Komori, A. Shinohara

    Journal of Radioanalytical and Nuclear Chemistry　301　(3)　751-756　2014/09

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1007/s10967-014-3208-9 　

    ISSN： 0236-5731

    eISSN： 1588-2780

  10. Imaging of gamma photons and X-rays emitted from lead-212 and its daughter radionuclides using a small field-of-view high-energy gamma camera and a low-energy X-ray camera Peer-reviewed

    Seiichi Yamamoto, Masao Yoshino, Kazuaki Tsukada, Hidetoshi Kikunaga, Takuya Yokokita, Kenji Shirasaki, Kohei Nakanishi, Kei Kamada, Akira Yoshikawa, Jun Kataoka

    Radiation Physics and Chemistry　251　114446-114446　2027/02

    Publisher: Elsevier BV

    DOI： 10.1016/j.radphyschem.2026.114446 　

    ISSN： 0969-806X

  11. Estimation of LET distributions of α -particles from measured scintillator-based trajectory images Peer-reviewed

    Seiichi Yamamoto, Kohei Nakanishi, Katsunori Yogo, Masao Yoshino, Kazuaki Tsukada, Hidetoshi Kikunaga, Takuya Yokokita, Kenji Shirasaki, Kei Kamada, Akira Yoshikawa, Jun Kataoka

    Physics in Medicine &amp; Biology　71　(17)　175003-175003　2026/09/01

    Publisher: IOP Publishing

    DOI： 10.1088/1361-6560/ae99a7 　

    ISSN： 0031-9155

    eISSN： 1361-6560

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    Abstract Objective . Linear energy transfer (LET) measurements of α -particles are increasingly important for micro-dosimetric evaluation in targeted α -radionuclide therapy. However, direct LET measurements remain challenging due to the extremely short range of α -particles in matter. In this study, we propose a method to estimate LET distributions using quenching effects observed in α -particle trajectory images. Approach. α -particle trajectories were imaged using an ultra-high-resolution imaging system consisting of a Gd 3 Al 2 Ga 3 O 12 scintillator, an optical magnification unit, and an electron-multiplying charge-coupled device camera. α -particles from three radionuclides were measured: Am-241 (5.5 MeV), Po-213 (8.4 MeV) and Po-212 (8.8 MeV). LET distributions were estimated by taking the ratio of simulated dose profiles (without quenching) to measured depth profiles of α -particle trajectory images (including quenching). The estimated LET distributions were then compared with those obtained from simulations. Main results . The relative LET distributions along the depth direction were successfully estimated from the measured depth profiles for all α -particles with different energies. The estimated relative LET distributions differed from the simulated distributions by no more than 11%–24% over the depth range from 5 µ m to the Bragg peak position. Approximate absolute LET distributions were also evaluated. Significance . The proposed method enables a simple and effective estimation of LET distributions of α -particles from measured depth profiles of trajectory images. It is applicable to α -particles with a wide range of energies and has potential for advancing micro-dosimetry in targeted α -radionuclide therapy.

  12. Body Distribution and Occupational Dispersion of Scandium-47 Chloride: Safety Considerations for Radiopharmaceutical Development Peer-reviewed

    Haruna Yorifuji, Yoshifumi Shirakami, Tadashi Watabe, Masashi Murakami, Kazuhiro Ooe, Kentaro Hisada, Atsufumi Akai, Sifan Feng, Hidetoshi Kikunaga, Takuya Yokokita, Kazuki Kajiyama, Akina Mitsukai, Atsushi Toyoshima, Takashi Yoshimura, Jens Cardinale, Frederik L. Giesel, Kazuko Kaneda-Nakashima

    Biophysica　6　(4)　71-71　2026/08/09

    Publisher: MDPI AG

    DOI： 10.3390/biophysica6040071 　

    eISSN： 2673-4125

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    This study investigated the distribution and dispersion of Sc-47 (47Sc), a β-emitting radionuclide that can be produced in large quantities using accelerators. As the stability of labeled compounds inside the body is essential for nuclear medicine therapy, we examined the biodistribution of free 47Sc to distinguish it from the distribution of compounds labeled with 47Sc. [47Sc]ScCl3 was administered to normal mice. Body distribution, excretion routes, and contamination of laboratory equipment were also measured. 47Sc remained in the blood for long periods and accumulated mainly in the liver and kidneys because of its binding to plasma proteins. Therefore, 47Sc released from the labeled compounds could potentially cause non-specific liver and kidney damage. Most of the 47Sc was eliminated through feces, whereas some was excreted through the urinary system. 47Sc was found in both the liquid and solid components of the blood. Although animal cages were contaminated with excreta, they could be effectively cleaned by wiping with paper. We also used 47Sc produced by us to label PSMA-617 and verified its performance as a nuclear medicine therapeutic agent. Although 47Sc-PSMA-617 did not exhibit a high accumulation rate in tumors, it demonstrated antitumor activity. This might suggest the usefulness of 47Sc.

  13. Macropa-Based 225Ac-Labeled RGD Peptides for Targeted Alpha Therapy Peer-reviewed

    Hiroaki Echigo, Masayuki Munekane, Takeshi Fuchigami, Kenji Mishiro, Hidetoshi Kikunaga, Kazuaki Tsukada, Takuya Yokokita, Kenji Shirasaki, Jun Ichinose, Eiichi Hinoi, Seigo Kinuya, Kazuma Ogawa

    Molecular Pharmaceutics　2026/08/03

    Publisher: American Chemical Society (ACS)

    DOI： 10.1021/acs.molpharmaceut.6c00344 　

    ISSN： 1543-8384

    eISSN： 1543-8392

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    Abstract Macropa has formed more stable complexes with 225Ac, although DOTA has been extensively used as a chelator for 225Ac. This study aimed to design and synthesize two novel 225Ac-labeled RGD peptides, [225Ac]Ac-Macropa-c(RGDyK) ([225Ac]1) and [225Ac]Ac-Macropa-[c(RGDyK)]2 ([225Ac]2), and to evaluate their potential for targeted alpha therapy (TAT) of glioblastoma. Further, whether combination therapy with homoarginine (hArg), a modulator of lysosomal function, could further improve therapeutic efficacy was investigated. In Colon-26 cells, [225Ac]2 demonstrated significantly higher cellular uptake and cytotoxicity than [225Ac]1. In Colon-26 tumor-bearing mice, [225Ac]2 exhibited higher tumor accumulation and significant tumor growth inhibition. In GL261 glioblastoma cells, [225Ac]2 showed comparable cellular uptake to that in Colon-26 cells, and combination with hArg in vitro improved its cytotoxicity. However, no significant difference in therapeutic efficacy was observed between the hArg-treated and control groups in the orthotopic GL261 glioblastoma mouse model. The results of this study indicate the potential of 225Ac-labeled RGD peptides incorporating Macropa as a chelator as promising agents for TAT. However, the further optimization of combination strategies and pharmacokinetics is required.

  14. Energy-resolved imaging of α particles emitted by the decay products of Pb-212 using a YAP(Ce)-based imaging detector for targeted radionuclide therapy Peer-reviewed

    Seiichi Yamamoto, Masao Yoshino, Kazuaki Tsukada, Hidetoshi Kikunaga, Takuya Yokokita, Kenji Shirasaki, Kohei Nakanishi, Kei Kamada, Akira Yoshikawa, Jun Kataoka

    Biomedical Physics &amp; Engineering Express　12　(4)　047005-047005　2026/08/01

    Publisher: IOP Publishing

    DOI： 10.1088/2057-1976/ae9c48 　

    eISSN： 2057-1976

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    Abstract Objective. Lead-212 (Pb-212) is attracting considerable interest as a radionuclide fortargeted α-therapy, yet energy-resolved imaging of α particles originating from its decay chain has been technically difficult. Approach. To address this issue, we employed a YAP(Ce)-based α -particle imaging detector to perform energy-resolved imaging of α particles emitted from Pb-212 progeny and evaluated its performance for energy-discriminative α -particle imaging. Main results. The system provided a spatial resolution better than 1.0 mm full width at half maximum (FWHM) and an energy resolution of approximately 14.9% (FWHM) for α particles. This performance made it possible to distinguish the two principal α -energy components emitted by the daughter nuclides of Pb-212, even in the presence of partial interference from β particles. To suppress this β -particle contribution, a 1 mm-thick acrylic plate was inserted between the Pb-212 source and the detector to selectively acquire β -particle images, which were then subtracted from the mixed images. The β -particle contribution was partially reduced using the proposed subtraction approach, although the contrast to noise ratio decreased after subtraction. Significance. The results demonstrate that practical energy-resolved imaging of α particles from Pb-212 progeny is achievable and that the proposed subtraction approach has the potential to reduce β -particle interference.

  15. Investigation toward the production of 236gNp via the 232Th + 7Li reaction: Synthesis of 236mNp and 234Np Peer-reviewed

    Akihisa Nakajima, Yuta Hayakawa, Ayumu Nagai, Akihiko Yokoyama, Hiromitsu Haba, Yukiko Komori, Takuya Yokokita, Yuma Sakakieda, Keisuke Sueki, Shinya Yamasaki, Aya Sakaguchi

    Applied Radiation and Isotopes　230　112397-112397　2026/04

    Publisher: Elsevier BV

    DOI： 10.1016/j.apradiso.2025.112397 　

    ISSN： 0969-8043

  16. Upper Limit for the 248Cm(50Ti, xn)298−xOg Reaction Cross Section Peer-reviewed

    Benoît Jean-Paul Gall, Kosuke Morita, Kouji Morimoto, Daiya Kaji, Satoshi Ishizawa, Toshitaka Niwase, Sayaka Yamaki, Hiromitsu Haba, Yukiko Komori, Takuya Yokokita, Krzysztof Piotr Rykaczewski, Kieran Kessaci, Zouhair Asfari, Martin Wladislas Bordeau, Taiki Tanaka, Pierre Brionnet, Hiroki Arakawa, Masato Asai, Olivier Dorvaux, Michel Filliger, Tomoya Fujii, Kunihiro Fujita, Shin-ichi Goto, Eiji Ideguchi, Kumi Inomata, Yuta Ito, Hidetoshi Kikunaga, Hisaaki Kudo, Shun Mitsuoka, Bertis Charlie Rasco, Hideyuki Sakai, Fuyuki Tokanai, Atsushi Toyoshima, Takayuki Yamaguchi

    Journal of the Physical Society of Japan　94　(9)　2025/09/15

    Publisher: Physical Society of Japan

    DOI： 10.7566/jpsj.94.094201 　

    ISSN： 0031-9015

    eISSN： 1347-4073

  17. Incomplete fusion reaction producing 234U, 233U, and 232U in the 232Th + 7Li reaction Peer-reviewed

    Ayumu Nagai, Hiroyuki Hosokawa, Kakeru Teranishi, Ryoga Morita, Ayano Seto, Akihisa Nakajima, Yukiko Komori, Takuya Yokokita, Daiki Mori, Yudai Shigekawa, Akihiro Nambu, Yang Wang, Aya Sakaguchi, Hiromitsu Haba, Akihiko Yokoyama

    Radiochimica Acta　2025/08/15

    Publisher: Walter de Gruyter GmbH

    DOI： 10.1515/ract-2025-0022 　

    ISSN： 0033-8230

    eISSN： 2193-3405

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    Abstract The nuclide of 237Np (t 1/2 = 2.1 × 106 y), produced in nuclear facilities, is important because its investigation is relevant to environmental pollution and material cycling in earth sciences. It is expected to be analyzed by mass spectrometry with a neptunium tracer as a spike, such as 236gNp (t 1/2 = 1.5 × 105 y). Our research group has collected fundamental data for cross-sections of the 232Th + 7Li reaction products for use in spike production and chemical separation. In addition to the complete fusion reaction producing Np nuclides, incomplete fusion also occurs, especially in the reaction of 7Li, which splits into α and t and only a part of the projectile fuses with the target nucleus. In this study, the excitation functions of 234U, 233U, and 232U, produced by the incomplete fusion, were measured. The reaction mechanism is discussed by comparing the experimental values with those calculated using the EMPIRE code. In addition, we investigated the effect of incomplete fusion on the overall reaction.

  18. pH dependence of perturbed angular correlation in DOTA chelated 111In measured with ring-shape gamma-ray detectors Peer-reviewed

    Kenji Shimazoe, Kim Donghwan, Tomoko Mineo, Takeshi Sato, Seiichi Ohta, Toshifumi Tatsumi, Akira Sugiyama, Kenzo Yamatsugu, Sachiyo Nomura, Ryohei Terabayashi, Hideki Tomita, Tetsu Sonoda, Yudai Shigekawa, Takuya Yokokita, Mizuki Uenomachi

    Interactions　245　(1)　22　2024/02/14

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1007/s10751-024-01864-7 　

    eISSN： 3005-0731

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    Abstract The conventional nuclear medical imaging, such as PET and SPECT, visualizes the accumulation of radioisotopes in the human body and has been widely used for diagnosis of cancer and other diseases. Perturbed angular correlation is a powerful sensing tool detecting local electro-magnetic environment and has been used for chemical analysis or nuclear physics research. The use of perturbed angular correlation in nuclear medicine is recently proposed and pH sensing capability with liquid $$^{111}$$In has been confirmed. In more practical applications, DOTA based radioisotope labeled drug delivery is common in nuclear medicine. This study aims to characterize the pH dependance of perturbed angular correlation in Psyche-DOTA chelated $$^{111}$$In with the custom ring-shape gamma-ray detectors. The observed transition in anisotropy of cascade gamma-ray emission can contribute to the detection of a specific phenomenon changing pH inside the human body.

  19. Incomplete fusion reaction producing Pa nuclides in the 232Th + 7Li reaction Peer-reviewed

    Kakeru Teranishi, Ryoga Morita, Yuta Hayakawa, Aya Sakaguchi, Akihisa Nakajima, Yukiko Komori, Takuya Yokokita, Daiki Mori, Hiromitsu Haba, Akihiko Yokoyama

    Radiochimica Acta　111　(8)　589-596　2023/06/05

    Publisher: Walter de Gruyter GmbH

    DOI： 10.1515/ract-2022-0093 　

    ISSN： 0033-8230

    eISSN： 2193-3405

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    Abstract The 237Np (t1/2 = 2.1 × 106 y) nuclide is produced in nuclear facilities. Its investigation is relevant to earth sciences as concerns environmental pollution and material circulation. We expected that this nuclide should be able to be analyzed by mass spectrometry with a neptunium tracer as a spike, such as that of 236gNp (t1/2 = 1.5 × 105 y). Our research group has collected fundamental data for cross-sections of the 232Th + 7Li reaction for use in spike production. In addition to the complete fusion reaction, incomplete fusion also occurs, especially in the reaction of 7Li, which splits into α and t, and only a part of the projectile fuses with the target nucleus. In this study, the excitation functions of Pa isotopes, as products of the incomplete fusion reaction, were measured. The reaction mechanism is discussed by comparing the experimental values with those calculated using the EMPIRE code. In addition, we investigated the effect of incomplete fusion reaction on the entire reaction.

  20. Probing Optimal Reaction Energy for Synthesis of Element 119 from 51V+248Cm Reaction with Quasielastic Barrier Distribution Measurement Peer-reviewed

    Masaomi Tanaka, Pierre Brionnet, Miting Du, Julie Ezold, Kevin Felker, Benoît J.P. Gall, Shintaro Go, Robert K. Grzywacz, Hiromitsu Haba, Kouichi Hagino, Susan Hogle, Satoshi Ishizawa, Daiya Kaji, Sota Kimura, Thomas T. King, Yukiko Komori, Raiden K. Lemon, Milan G. Leonard, Kouji Morimoto, Kosuke Morita, Daisuke Nagae, Natsuki Naito, Toshitaka Niwase, Bertis C. Rasco, James B. Roberto, Krzysztof P. Rykaczewski, Satoshi Sakaguchi, Hideyuki Sakai, Yudai Shigekawa, Daniel W. Stracener, Shelley VanCleve, Yang Wang, Kouhei Washiyama, Takuya Yokokita

    Journal of the Physical Society of Japan　91　(8)　2022/08/15

    DOI： 10.7566/jpsj.91.084201 　

    ISSN： 0031-9015

    eISSN： 1347-4073

  21. Anion-exchange Experiment of Zr, Hf, and Th in HNO3 and Quantum Chemical Study on the Nitrate Complexes toward Chemical Research on Element 104, Rf Peer-reviewed

    Eisuke Watanabe, Yoshitaka Kasamatsu, Takuya Yokokita, Sho Hayami, Katsuma Tonai, Hidemi Ninomiya, Narumi Kondo, Yudai Shigekawa, Hiromitsu Haba, Yasutaka Kitagawa, Masayoshi Nakano, Atsushi Shinohara

    Solvent Extraction and Ion Exchange　40　(6)　1-16　2021/12/31

    DOI： 10.1080/07366299.2021.2020956 　

    ISSN： 0736-6299

    eISSN： 1532-2262

  22. Production cross sections of dysprosium, terbium and gadolinium radioisotopes from the alpha-particle-induced reactions on natural gadolinium up to 50 MeV Peer-reviewed

    Dagvadorj Ichinkhorloo, Masayuki Aikawa, Zolbadral Tsoodol, Tomohiro Murata, Michiya Sakaguchi, Yukiko Komori, Takuya Yokokita, Hiromitsu Haba

    Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms　499　46-52　2021/07

    Publisher: Elsevier BV

    DOI： 10.1016/j.nimb.2021.04.018 　

    ISSN： 0168-583X

  23. Stabilization of an 211At-Labeled Antibody with Sodium Ascorbate Peer-reviewed

    Shino Manabe, Hiroki Takashima, Kazunobu Ohnuki, Yoshikatsu Koga, Ryo Tsumura, Nozomi Iwata, Yang Wang, Takuya Yokokita, Yukiko Komori, Sachiko Usuda, Daiki Mori, Hiromitsu Haba, Hirofumi Fujii, Masahiro Yasunaga, Yasuhiro Matsumura

    ACS Omega　6　(23)　14887-14895　2021/05/31

    Publisher: American Chemical Society (ACS)

    DOI： 10.1021/acsomega.1c00684 　

    ISSN： 2470-1343

    eISSN： 2470-1343

  24. Radioimmunotherapy with an 211 At‐labeled anti–tissue factor antibody protected by sodium ascorbate International-journal Peer-reviewed

    Hiroki Takashima, Yoshikatsu Koga, Shino Manabe, Kazunobu Ohnuki, Ryo Tsumura, Takahiro Anzai, Nozomi Iwata, Yang Wang, Takuya Yokokita, Yukiko Komori, Daiki Mori, Sachiko Usuda, Hiromitsu Haba, Hirofumi Fujii, Yasuhiro Matsumura, Masahiro Yasunaga

    Cancer Science　112　(5)　1975-1986　2021/03/30

    Publisher: Wiley

    DOI： 10.1111/cas.14857 　

    ISSN： 1347-9032

    eISSN： 1349-7006

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    Tissue factor (TF), the trigger protein of the extrinsic blood coagulation cascade, is abundantly expressed in various cancers including gastric cancer. Anti-TF monoclonal antibodies (mAbs) capable of targeting cancers have been successfully applied to armed antibodies such as antibody-drug conjugates (ADCs) and molecular imaging probes. We prepared an anti-TF mAb, clone 1084, labeled with astatine-211 (211 At), as a promising alpha emitter for cancer treatment. Alpha particles are characterized by high linear energy transfer and a range of 50-100 µm in tissue. Therefore, selective and efficient tumor accumulation of alpha emitters results in potent antitumor activities against cancer cells with minor effects on normal cells adjacent to the tumor. Although the 211 At-conjugated clone 1084 (211 At-anti-TF mAb) was disrupted by an 211 At-induced radiochemical reaction, we demonstrated that astatinated anti-TF mAbs eluted in 0.6% or 1.2% sodium ascorbate (SA) solution were protected from antibody denaturation, which contributed to the maintenance of cellular binding activities and cytocidal effects of this immunoconjugate. Although body weight loss was observed in mice administered a 1.2% SA solution, the loss was transient and the radioprotectant seemed to be tolerable in vivo. In a high TF-expressing gastric cancer xenograft model, 211 At-anti-TF mAb in 1.2% SA exerted a significantly greater antitumor effect than nonprotected 211 At-anti-TF mAb. Moreover, the antitumor activities of the protected immunoconjugate in gastric cancer xenograft models were dependent on the level of TF in cancer cells. These findings suggest the clinical availability of the radioprotectant and applicability of clone 1084 to 211 At-radioimmunotherapy.

  25. Image reconstruction method for dual-isotope positron emission tomography Peer-reviewed

    T. Fukuchi, M. Shigeta, H. Haba, D. Mori, T. Yokokita, Y. Komori, S. Yamamoto, Y. Watanabe

    Journal of Instrumentation　16　P01035　2021/01

  26. Production of Bh266 in the Cm248(Na23,5n)Bh266 reaction and its decay properties Peer-reviewed

    H. Haba, F. Fan, D. Kaji, Y. Kasamatsu, H. Kikunaga, Y. Komori, N. Kondo, H. Kudo, K. Morimoto, K. Morita, M. Murakami, K. Nishio, J. P. Omtvedt, K. Ooe, Z. Qin, D. Sato, N. Sato, T. K. Sato, Y. Shigekawa, A. Shinohara, M. Takeyama, T. Tanaka, A. Toyoshima, K. Tsukada, Y. Wakabayashi, Y. Wang, S. Wulff, S. Yamaki, S. Yano, Y. Yasuda, T. Yokokita

    Physical Review C　102　(2)　024625　2020/08/27

    DOI： 10.1103/physrevc.102.024625 　

    ISSN： 2469-9985

    eISSN： 2469-9993

  27. Solvent Extraction of Zr and Hf from HCl by Aliquat 336 using a Flow-Type Extraction Apparatus Toward Online Chemical Studies of Element 104, Rutherfordium Peer-reviewed

    Yoshitaka Kasamatsu, Narumi Kondo, Kouhei Nakamura, Yuki Kuboki, Hidemi Ninomiya, Yudai Shigekawa, Eisuke Watanabe, Yuki Yasuda, Keigo Toyomura, Masahiro Nagase, Takuya Yokokita, Yukiko Komori, Hiromitsu Haba, Takashi Yoshimura, Hideyuki Itabashi, Atsushi Shinohara

    Solvent Extraction and Ion Exchange　38　(3)　318-327　2020/04/15

    Publisher: Informa UK Limited

    DOI： 10.1080/07366299.2020.1726075 　

    ISSN： 0736-6299

    eISSN： 1532-2262

  28. 高輝度X線を用いた核共鳴散乱技術による原子核229Thアイソマー状態の人工生成

    海野弘行, 笠松良崇, 重河優大, 羽場宏光, 平木貴宏, 増田孝彦, 山口敦史, 横北卓也, 吉見彰洋, 吉村浩司

    Isotope News　768　2-6　2020/04

  29. 211At-labeled immunoconjugate via a one-pot three-component double click strategy: practical access to α-emission cancer radiotherapeutics International-journal Peer-reviewed

    Katsumasa Fujiki, Yousuke Kanayama, Shinya Yano, Nozomi Sato, Takuya Yokokita, Peni Ahmadi, Yasuyoshi Watanabe, Hiromitsu Haba, Katsunori Tanaka

    Chemical Science　10　(7)　1936-1944　2019

    Publisher: Royal Society of Chemistry (RSC)

    DOI： 10.1039/c8sc04747b 　

    ISSN： 2041-6520

    eISSN： 2041-6539

    More details Close

    <p>A facile synthesis of an 211At-labeled immunoconjugate for α-emission therapy was achieved based on a one-pot three-component double click method.</p>

  30. The study of rhenium pentacarbonyl complexes using single-atom chemistry in the gas phase Peer-reviewed

    Yang Wang, Shiwei Cao, Jicai Zhang, Fangli Fan, Jie Yang, Hiromitsu Haba, Yukiko Komori, Takuya Yokokita, Kouji Morimoto, Daiya Kaji, Yves Wittwer, Robert Eichler, Andreas Türler, Zhi Qin

    Physical Chemistry Chemical Physics　21　(13)　7147-7154　2019

    DOI： 10.1039/c8cp07844k 　

    ISSN： 1463-9076

    eISSN： 1463-9084

  31. Coprecipitation experiment with Sm hydroxide using a multitracer produced by nuclear spallation reaction: A tool for chemical studies with superheavy elements Peer-reviewed

    Yoshitaka Kasamatsu, Takuya Yokokita, Keigo Toyomura, Yudai Shigekawa, Hiromitsu Haba, Jumpei Kanaya, Minghui Huang, Yutaka Ezaki, Takashi Yoshimura, Kosuke Morita, Atsushi Shinohara

    Applied Radiation and Isotopes　118　105-116　2016/12

    Publisher: Elsevier BV

    DOI： 10.1016/j.apradiso.2016.09.003 　

    ISSN： 0969-8043

  32. Solid–liquid extraction of Mo and W by Aliquat 336 from HCl solutions toward extraction chromatography experiments of Sg Peer-reviewed

    Y. Komori, T. Yokokita, Y. Kasamatsu, H. Haba, A. Toyoshima, K. Toyomura, K. Nakamura, J. Kanaya, M. Huang, Y. Kudou, N. Takahashi, A. Shinohara

    Journal of Radioanalytical and Nuclear Chemistry　303　(2)　1385-1388　2015/02

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1007/s10967-014-3476-4 　

    ISSN： 0236-5731

    eISSN： 1588-2780

  33. Development of a new continuous dissolution apparatus with a hydrophobic membrane for superheavy element chemistry Peer-reviewed

    K. Ooe, M. F. Attallah, M. Asai, N. Goto, N. S. Gupta, H. Haba, M. Huang, J. Kanaya, Y. Kaneya, Y. Kasamatsu, Y. Kitatsuji, Y. Kitayama, K. Koga, Y. Komori, T. Koyama, J. V. Kratz, H. V. Lerum, S. Miyashita, Y. Oshimi, V. Pershina, D. Sato, T. K. Sato, Y. Shigekawa, A. Shinohara, A. Tanaka, A. Toyoshima, K. Tsukada, S. Tsuto, T. Yokokita, A. Yokoyama, J. P. Omtvedt, Y. Nagame, M. Schädel

    Journal of Radioanalytical and Nuclear Chemistry　303　(2)　1317-1320　2015/02

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1007/s10967-014-3469-3 　

    ISSN： 0236-5731

    eISSN： 1588-2780

  34. Measurement of evaporation-residue cross sections with light beams and deformed lanthanide target nuclei Peer-reviewed

    S. Ueno, K. Toda, A. Asano, N. Takahashi, Y. Kasamatsu, T. Yokokita, A. Yokoyama

    Journal of Radioanalytical and Nuclear Chemistry　303　(2)　1273-1276　2015/02

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1007/s10967-014-3632-x 　

    ISSN： 0236-5731

    eISSN： 1588-2780

  35. Chemical studies of Mo and W in preparation of a seaborgium (Sg) reduction experiment using MDG, FEC, and SISAK Peer-reviewed

    A. Toyoshima, K. Ooe, S. Miyashita, M. Asai, M. F. Attallah, N. Goto, N. S. Gupta, H. Haba, M. Huang, J. Kanaya, Y. Kaneya, Y. Kasamatsu, Y. Kitatsuji, Y. Kitayama, K. Koga, Y. Komori, T. Koyama, J. V. Kratz, H. V. Lerum, Y. Oshimi, V. Pershina, D. Sato, T. K. Sato, Y. Shigekawa, A. Shinohara, A. Tanaka, K. Tsukada, S. Tsuto, T. Yokokita, A. Yokoyama, J. P. Omtvedt, Y. Nagame, M. Schädel

    Journal of Radioanalytical and Nuclear Chemistry　303　(2)　1169-1172　2015/02

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1007/s10967-014-3438-x 　

    ISSN： 0236-5731

    eISSN： 1588-2780

  36. Development of an automated batch-type solid-liquid extraction apparatus and extraction of Zr, Hf, and Th by triisooctylamine from HCl solutions for chemistry of element 104, Rf Peer-reviewed

    Yoshitaka Kasamatsu, Aiko Kino, Takuya Yokokita, Kouhei Nakamura, Yukiko Komori, Keigo Toyomura, Takashi Yoshimura, Hiromitsu Haba, Jumpei Kanaya, Minghui Huang, Yuki Kudou, Naruto Takahashi, Atsushi Shinohara

    Radiochimica Acta　103　(7)　2015/01/28

    Publisher: Walter de Gruyter GmbH

    DOI： 10.1515/ract-2014-2283 　

    ISSN： 0033-8230

    eISSN： 2193-3405

    More details Close

    <title>Abstract</title>Solid-liquid extraction of the group 4 elements Zr and Hf, which are homologues of Rf (

  37. Solvent Extraction of Zirconium and Hafnium as Homologues of Rutherfordium by Triisooctylamine from HCl Solutions Peer-reviewed

    A. Kino, Y. Kasamatsu, T. Yokokita, T. Yoshimura, Y. Komori, Y. Kikutani, N. Takahashi, A. Shinohara

    Solvent Extraction Research and Development, Japan　22　(2)　127-134　2015

    DOI： 10.15261/serdj.22.127 　

    ISSN： 1341-7215

  38. Coprecipitation Behaviors of Zr, Hf, and Th with Sm Hydroxide for Chemical Study of Element 104, Rf Peer-reviewed

    Y. Kasamatsu, K. Toyomura, N. Shiohara, T. Yokokita, Y. Komori, A. Kino, T. Yoshimura, N. Takahashi, H. Haba, Y. Kudou, H. Kikunaga, T. Mitsugashira, T. Ohtsuki, K. Takamiya, A. Shinohara

    Journal of Nuclear and Radiochemical Sciences　14　(2)　7-11　2014

    Publisher: The Japan Society of Nuclear and Radiochemical Sciences

    DOI： 10.14494/jnrs.14.7 　

    ISSN： 1345-4749

    eISSN： 1883-5813

  39. Solvent extraction of Zr and Hf from hydrochloric acid using tributylphosphate for the extraction of element 104, rutherfordium Peer-reviewed

    Y. Kasamatsu, Y. Kikutani, A. Kino, Y. Komori, T. Yokokita, T. Yoshimura, N. Takahashi, A. Shinohara

    RADIOCHIMICA ACTA　101　(8)　515-518　2013

    DOI： 10.1524/ract.2013.2056 　

    ISSN： 0033-8230

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Misc. 20

  1. Elucidation of the salt tolerance mechanism of Na+ transporters during reproductive stage

    内山剛志, 佐藤悠仁, 吉田哲, 加藤恵, 横北卓也, 菊永英寿, 辻井雅, 石丸泰寛, 魚住信之

    日本農芸化学会大会講演要旨集(Web)　2025　2025

    ISSN： 2186-7976

  2. Novel synthesis of [191Pt]cisplatin using radiolabeled platinum and development of molecular imaging platform technologies

    面川真里奈, 横北卓也, 菊永英寿, 大重聡友, 北村陽二, 木村寛之

    Biomedical Research on Trace Elements (Web)　36　(S1)　2025

    ISSN： 1880-1404

  3. SEKIGUCHI Three-body Nuclear Force Project: Consideration of the optimal production method for Auger electron emitter 77Br using the CCONE-based calculation system

    酒井聖矢, 大津秀暁, 岩本修, 岩本信之, 中山梓介, 深堀智生, 菊永英寿, 横北卓也

    日本原子力学会春の年会予稿集(CD-ROM)　2025　2025

  4. Elucidation of the Mechanisms of Potassium Utilization Mediated by High-Affinity Potassium Transporters in Arabidopsis thaliana

    山梨太郎, 内山剛志, 堀越智也, 高木智子, 吉田哲, 池田隼人, 横北卓也, 菊永英寿, 清水未崎, 斎藤芳郎, 三輪美沙子, 遠山翔, 松山成男, 永田典子, 山上睦, TANUDJAJA Ellen, 石丸泰寛, 魚住信之

    日本植物生理学会年会(Web)　66th　2025

  5. Attempt to verify the excitation function of the 226Ra(γ,n) reaction

    菊永英寿, 横北卓也, 白崎謙次

    日本放射化学会討論会(Web)　68th　2024

  6. Production of radioactive cisplatin by photonuclear reaction

    横北卓也, 本多佑記, 木村寛之, 重河優大, 羽場宏光, 菊永英寿

    日本放射化学会討論会(Web)　68th　2024

  7. Estimation of the production of medium and long-lived nuclides from photonuclear reactions.

    菊永英寿, 横北卓也

    日本放射化学会討論会(Web)　67th　2023

  8. Production of Sb-125 by natTe(γ,x)125Sb reaction

    横北卓也, 本多佑記, 菊永英寿

    日本放射化学会討論会(Web)　67th　2023

  9. Development of a Multi-Photon Gamma-Ray Coincidence Imaging Method (3) Production of Multi-Photon Emitting Radionuclides

    羽場宏光, 横北卓也, WANG Yang, 南部明弘, 臼田祥子, 高橋浩之, 島添健次, 鎌田圭, 百瀬敏光, 高橋美和子

    応用物理学会春季学術講演会講演予稿集(CD-ROM)　68th　2021

    ISSN： 2758-4704

  10. Preclinical evaluation of astatine-211-conjugated anti-tissue factor antibody

    Hiroki Takashima, Yoshikatsu Koga, Kazunobu Onuki, Shino Manabe, Ryo Tsumura, Takahiro Anzai, Nozomi Iwata, Masahiro Yasunaga, Wang Yang, Takuya Yokokita, Yukiko Komori, Daiki Mori, Hiromitsu Haba, Hirofumi Fujii, Yasuhiro Matsumura

    CANCER RESEARCH　80　(16)　2020/08

    DOI： 10.1158/1538-7445.AM2020-2863 　

    ISSN： 0008-5472

    eISSN： 1538-7445

  11. Production and separation of theranostic radionuclide Ag-111 from Pd target

    K. Ooe, T. Watabe, Y. Shirakami, D. Mori, T. Yokokita, Y. Komori, H. Haba, J. Hatazawa

    The Journal of Nuclear Medicine　61　(1)　1116-1116　2020/05

  12. Study on a Multi-Photon Gamma-Ray Coincidence Imaging Method: 3 (RI Production)

    羽場宏光, 森大輝, 小森有希子, 横北卓也, WANG Yang, 高橋浩之, 島添健次, 鎌田圭, 百瀬敏光, 高橋美和子

    応用物理学会春季学術講演会講演予稿集(CD-ROM)　67th　2020

    ISSN： 2758-4704

  13. Production and chemical purification of Ag-111 toward nuclear medical application

    大江一弘, 大江一弘, 渡部直史, 渡部直史, 白神宜史, 森大輝, 横北卓也, 小森有希子, 羽場宏光, 畑澤順, 畑澤順

    日本放射化学会討論会(Web)　64th　2020

  14. 多光子イメージング用カリウム43の製造技術開発

    羽場宏光, 小森有希子, 横北卓也, 森大輝, 高橋浩之, 島添健次, 鎌田圭, 百瀬敏光, 高橋美和子

    応用物理学会春季学術講演会講演予稿集(CD-ROM)　66th　2019

    ISSN： 2758-4704

  15. Measurement of radioactivity of 211At, an alpha emitter at medical facilities

    藤井博史, 大貫和信, 高島大輝, 古賀宣勝, 津村遼, 松村保広, 羽場宏光, YANG Wang, GHOSH Kaustab, 小森有希子, 横北卓也, 森大輝, 眞鍋史乃

    JSMI Report　12　(2)　2019

    ISSN： 1882-6490

  16. マルチトレーサーを用いた様々な元素の水酸化サマリウム共沈実験

    笠松良崇, 豊村恵悟, 横北卓也, 羽場宏光, 金谷淳平, 工藤祐生, 森田浩介, 菊永英寿, 大槻勤, 三頭聰明, 篠原厚

    日本化学会講演予稿集　94th　(2)　2014

    ISSN： 0285-7626

  17. 104番元素Rfの希アンモニア水中でのサマリウム共沈挙動

    豊村恵悟, 笠松良崇, 横北卓也, 塩原直也, 小森有希子, 重河優大, 吉村崇, 高橋成人, 菊永英寿, 大槻勤, 三頭聰明, 羽場宏光, 金谷淳平, HUANG Minghui, 村上昌史, 工藤祐生, 森田浩介, 高宮幸一, 篠原厚

    日本化学会講演予稿集　94th　(2)　2014

    ISSN： 0285-7626

  18. 104番元素Rfの水酸化サマリウム共沈挙動

    笠松良崇, 豊村恵悟, 横北卓也, 重河優大, 高橋成人, 羽場宏光, 小森有希子, 金谷淳平, 黄明輝, 森田浩介, 村上昌史, 村上昌史, 菊永英寿, 三頭聰明, 吉村崇, 大槻勤, 高宮幸一, 篠原厚

    日本放射化学会年会・放射化学討論会研究発表要旨集　2014-58th　2014

    ISSN： 1345-2762

  19. 104番元素Rfの水酸化物沈殿作成に向けた基礎研究

    笠松良崇, 塩原直也, 小森有希子, 菊谷有希, 横北卓也, 木野愛子, 吉村崇, 高橋成人, 菊永英寿, 大槻勤, 三頭聰明, 羽場宏光, 高宮幸一, 篠原厚

    日本化学会講演予稿集　92nd　(2)　2012

    ISSN： 0285-7626

  20. シーボーギウムの溶液化学実験に向けた液体シンチレーション検出システムの開発

    小森有希子, 菊谷有希, 横北卓也, 木野愛子, 菊永英寿, 笠松良崇, 吉村崇, 高橋成人, 篠原厚

    日本放射化学会年会・放射化学討論会研究発表要旨集　2011-55th　2011

    ISSN： 1345-2762

Show all ︎Show first 5

Presentations 9

  1. Purification of 195Au tracer using UTEVA resin column chromatography

    Takuya Yokokita, Yudai Shigekawa, Akihiro Nambu, Michiko Kitagawa, Hiromitsu Haba

    20th Workshop on Targetry and Target Chemistry　2026/08/27

  2. 104番元素Rfの臭化物錯形成の研究に向けたZr及びHfのHBr系の陽イオン交換、陰イオン交換、TBP固液抽出実験及び紫外可視吸光測定

    横北卓也

    2026重元素化学研究会　2026/05/31

  3. 43Kの精製法の改良と43Kを利用した植物のK輸送機構の解明

    横北卓也、内山剛志

    第15回 東北大学若手アンサンブルワークショップ　2025/12/12

  4. 電子加速器によるCu-64の製造: TOMOEプロジェクトにおけるCu-64の供給について

    横北卓也

    第3回短寿命 RI 利⽤研究シンポジウム　2025/11/28

  5. Production of carrier-free 182Ta tracer via photonuclear reaction

    Takuya Yokokita, Yuki Honda, Hidetoshi Kikunaga

    7th Asia-Pacific Symposium On RadioChemistry (APSORC25)

  6. 陰イオン交換によるα線内用療法用核種225Ac精製法の検討

    横北卓也, 白﨑謙次, 塚田和明, 菊永英寿

    第13回東北大学若手研究者アンサンブルワークショップ　2024/12/11

  7. 光核反応による放射化シスプラチンの製造

    横北卓也, 本多佑記, 木村寛之, 重河優大, 羽場宏光, 菊永英寿

    日本放射化学会第68回討論会 (2024)　2024/09/23

  8. 電子線形加速器を利用したRI製造 Invited

    横北卓也

    RARiS研究会C038 「加速器を用いたガンマ線ビームの生成、基礎科学と産業分野への利用」　2024/09/10

  9. 学内で行っているRI製造

    横北卓也

    第14回東北大学若手アンサンブルワークショップ　2025/05/13

Show all Show first 5

Industrial Property Rights 2

  1. 目的核種の生成方法

    田沢 周作, 竹村 友紀, 結城 真美, 竹内 康隆, 芝原 裕規, 羽場 宏光, 横北 卓也

    特許第7693170号

    Property Type: Patent

  2. 放射性廃液の処理方法及び処理装置

    住谷貴子, 菅野真貴, 野下健司, 三宅俊介, 三宮豊, 横北卓也, 山口献, 小林敬, 山根正嗣, 増子雄太

    特許6271625

    Property Type: Patent

Research Projects 2

  1. もつれ光子対放出原子核と分子プローブの創成による生体内化学環境の医療診断

    重河 優大, 杉山 暁, 野村 幸世, 横北 卓也

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 学術変革領域研究(B)

    Institution: 国立研究開発法人理化学研究所

    2022/05/20 - 2025/03/31

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    もつれγ線分子間相互作用イメージング用RIの候補の一つであるYb-169の製造開発を進めた。まず、169Tm(d,2n)169Yb反応の核反応断面積を測定し、Yb-169の大量製造に適した重陽子のエネルギーや標的厚などを決定した。また、大量のTm-169標的からごく微量の169Ybを化学的に分離する手法を開発し、Yb-169を90%近い化学収率でTm-169標的から分離できるようになった。今年度開発した手法を用いて、1回のビームタイムで100 MBq程度のYb-169をイメージング実験に供することができると考えられる。 がん細胞表面のHER2に結合するVHH抗体およびaffibodyを使用した２種類のタンパク質プローブの作製と蛍光FITCおよびキレート剤DOTAの低分子プローブの作製を行った。タンパク質プローブについて、VHHを使用したものは、結合後の内在化が速いがaffibodyタイプの内在化は遅いことを蛍光低分子プローブで確認した。これらのタンパク質プローブとDOTAプローブを用いて細胞内のpH変化によるもつれガンマ線角相関解析の準備中である。 すでに細胞株として樹立できている免疫コンピテントなC57BL/6マウスに移植可能なマウス胃癌細胞株YTN16の適切なマウスへの移植法を確立した。腹膜播種に関しては、コンフルエントな細胞を1x10^7 cell/500 ulを一個体に対して移植し、1週間ですでに腹膜に播種があることは腹膜のざらつきで肉眼的にも視認できることを確認した。5週間になるとマウスに死亡個体が出ることも確認した。皮下腫瘍に関しても、5x10^6 cell/200ulを皮下注することにより、徐々に増大する腫瘍を形成できた。皮下腫瘍は5週間ではマウスの生命を脅かすほどの増大はない。イメージングへ向けて、ヒトHER2を発現するYTN16細胞を作成準備中である。

  2. Rfのハロゲン化物錯形成の系統的議論に向けた第４族元素の臭化物錯形成の研究

    横北 卓也

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業 若手研究

    Category: 若手研究

    Institution: 国立研究開発法人理化学研究所

    2020/04 - 2023/03

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    Rfの同族元素のZr及びHfの臭化水素酸系のイオン交換及びUV-visスペクトルの測定を行い、陽イオン交換挙動とUV-visスペクトルの変化の関連性が見られたものの、臭化水素酸系でのRfのイオン交換の研究が難しそうであることがわかった。一方で、Rfの比較となるZrとHfのイオン交換挙動と化学種の変化の様子を調べる手法開発は、今後のRfの化学研究に必要不可欠であるため、同族元素のZrとHfの臭化物錯形成の研究は進めている。その中で、同族元素のZrとHfの化学種情報を調べる手法を開発するため、これまでに実験を行ってきたZrとHfの塩酸及び硫酸系の溶媒抽出とESI-MSスペクトルの測定により、ZrとHfの化学種の同定手法の開発を行った。その結果、これまでに報告のあるZr及びHfの化学種情報が得られ、溶媒抽出と質量分析の組み合わせにより、ZrとHfの候補化学種の推定の道筋がたった。 このような中で、過去に行ったRf及び同族元素のZrとHf、擬似同族元素のThの硫酸系の陰イオン交換挙動を再評価することとなった。ZrとHfについては、ESI-MSスペクトルとトリオクチルアミンによる溶媒抽出の結果を基に、硫酸中での溶存化学種の候補を推定することができた。今後さらなる分析を行うことで、硫酸中でのZrとHfの化学種同定につなげることができると考えている。また、RfとZr、Hf、Thの陰イオン交換挙動の比較により、Rfの硫酸錯形成についてさらなる考察を行うことができる可能性が見えてきた。

Teaching Experience 5

  1. Organic chemistry　Salesian Polytechnic

  2. Introduction to Science　Salesian Polytechnic

  3. Fundamentals of Natural Science　Salesian Polytechnic

  4. Information Ethics　Salesian Polytechnic

  5. Chemistry　Salesian Polytechnic

Works 1

  1. 知の拠点【すぐわかアカデミア。】講演135 : すぐにわかる放射性同位体とその製造

    横北卓也

    Youtube 国立大学共同利用・共同研究拠点協議会 2025/12/19 - Present

    Type: Other