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Ichihashi F, Tanigaki T, Akashi T, Takahashi Y, Kusada K, Tamaoka T, Kitagawa H, Shinada H, Murakami Y. Improved Efficiency in Automated Acquisition of Ultra-high Resolution Electron Holograms Using Automated Target Detection. Microscopy (Oxf) 2021; 70:510-518. [PMID: 34101814 DOI: 10.1093/jmicro/dfab021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 06/02/2021] [Accepted: 06/08/2021] [Indexed: 11/14/2022] Open
Abstract
An automated hologram acquisition system for big-data analysis and for improving the statistical precision of phase analysis has been upgraded with automated particle detection technology. The coordinates of objects in low-magnification images are automatically detected using zero-mean normalized cross-correlation with preselected reference images. In contrast with the conventional scanning acquisitions from the whole area of a microgrid and/or a thin specimen, the new method allows efficient data collections only from the desired fields of view including the particles. The acquisition time of the cubic/triangular nanoparticles that were observed was shortened by about 1/58 that of the conventional scanning acquisition method because of the efficient data collections. The developed technology can improve statistical precision in electron holography with shorter acquisition time and is applicable to the analysis of electromagnetic fields for various kinds of nanoparticles.
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Affiliation(s)
- Fumiaki Ichihashi
- Research & Development Group, Hitachi, Ltd, Hatoyama, Saitama 350-0395, Japan
| | - Toshiaki Tanigaki
- Research & Development Group, Hitachi, Ltd, Hatoyama, Saitama 350-0395, Japan
| | - Tetsuya Akashi
- Research & Development Group, Hitachi, Ltd, Hatoyama, Saitama 350-0395, Japan
| | - Yoshio Takahashi
- Research & Development Group, Hitachi, Ltd, Hatoyama, Saitama 350-0395, Japan
| | - Kohei Kusada
- Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Takehiro Tamaoka
- The Ultramicroscopy Research Center, Kyushu University, Fukuoka 819-0395, Japan
| | - Hiroshi Kitagawa
- Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Hiroyuki Shinada
- Research & Development Group, Hitachi, Ltd, Hatoyama, Saitama 350-0395, Japan
| | - Yasukazu Murakami
- The Ultramicroscopy Research Center, Kyushu University, Fukuoka 819-0395, Japan.,Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Fukuoka 819-0395, Japan
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Danev R, Iijima H, Matsuzaki M, Motoki S. Fast and accurate defocus modulation for improved tunability of cryo-EM experiments. IUCRJ 2020; 7:566-574. [PMID: 32431839 PMCID: PMC7201282 DOI: 10.1107/s205225252000408x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 03/24/2020] [Indexed: 05/31/2023]
Abstract
Current data collection strategies in electron cryo-microscopy (cryo-EM) record multiframe movies with static optical settings. This limits the number of adjustable parameters that can be used to optimize the experiment. Here, a method for fast and accurate defocus (FADE) modulation during movie acquisition is proposed. It uses the objective lens aperture as an electrostatic pole that locally modifies the electron beam potential. The beam potential variation is converted to defocus change by the typically undesired chromatic aberration of the objective lens. The simplicity, electrostatic principle and low electrical impedance of the device allow fast switching speeds that will enable per-frame defocus modulation of cryo-EM movies. Researchers will be able to define custom defocus 'recipes' and tailor the experiment for optimal information extraction from the sample. The FADE method could help to convert the microscope into a more dynamic and flexible optical platform that delivers better performance in cryo-EM single-particle analysis and electron cryo-tomography.
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Affiliation(s)
- Radostin Danev
- Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Tokyo 113-0033, Japan
| | - Hirofumi Iijima
- JEOL Ltd, 1-2 Musashino 3-Chome, Akishima, Tokyo 196-8558, Japan
| | - Mizuki Matsuzaki
- JEOL Ltd, 1-2 Musashino 3-Chome, Akishima, Tokyo 196-8558, Japan
| | - Sohei Motoki
- JEOL Ltd, 1-2 Musashino 3-Chome, Akishima, Tokyo 196-8558, Japan
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Tamura T, Nakane Y, Nakajima H, Mori S, Harada K, Takai Y. Phase retrieval using through-focus images in Lorentz transmission electron microscopy. Microscopy (Oxf) 2018; 67:171-177. [PMID: 29590408 DOI: 10.1093/jmicro/dfy014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 02/23/2018] [Indexed: 11/13/2022] Open
Abstract
In this study, we report on phase retrieval by the maximum likelihood method with conjugate gradient method (CG-MAL) using through-focus images in Lorentz transmission electron microscopy (LTEM). The method was evaluated using 32 simulated and experimentally obtained through-focus images of magnetic bubbles; these images were collected under a defocus range from approximately -3 mm to 3 mm. Consequently, we obtained the magnetic domain structures of the magnetic bubbles in both the simulation and the LTEM experiment. Furthermore, the CG-MAL method showed better convergence behavior than other iterative phase retrieval methods. Therefore, the method can also be widely and effectively applied to the observation of magnetic domain structures other than magnetic bubbles when highly defocused through-focus images are used.
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Affiliation(s)
- Takahiro Tamura
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan
| | - Yukinori Nakane
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan
| | - Hiroshi Nakajima
- Department of Materials Science, Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan
| | - Shigeo Mori
- Department of Materials Science, Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan
| | - Ken Harada
- Department of Materials Science, Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan.,Center for Emergent Matter Science, Institute of Physical and Chemical Research (RIKEN), Hatoyama, Saitama 350-0395, Japan
| | - Yoshizo Takai
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan
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