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1. Optical Discrimination of TSDs and TEDs in 4H-SiC Substrates and Epitaxial Layers by Phase Contrast Microscopy Method

Author

Kazutsugu Murakami, Osamu Oku, Masaaki Kuzuhara, Ryuichi Sugie, and Ryo Hattori

Subjects
010302 applied physics, Materials science, Photoluminescence, business.industry, Mechanical Engineering, Phase contrast microscopy, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Epitaxy, 01 natural sciences, law.invention, Mechanics of Materials, law, 0103 physical sciences, Optoelectronics, General Materials Science, 0210 nano-technology, business
Abstract

Phase contrast microscopy (PCM) technique was demonstrated as the effective non-destructive discrimination method of TSDs and TEDs in 4H-SiC epitaxial layers in comparison with conventional polarized light microscopy, PL topography, KOH etch pit inspection and X-ray topography. The appearance of TSDs and TEDs by the PCM method is subtly modified by not only the consisting burgers vector but also the crystalline quality of the epitaxial layer or the substrate as the background. To extract more detailed information on the dislocations, the PCM inspection requires further investigation.

Published
2019

2. Infrared Microspectroscopy of Bionanomaterials (Diatoms) with Careful Evaluation of Void Effects

Author

Osamu Oku, Masanari Furiki, Leila Alipour, Rika Harui, Satoru Nakashima, and Mai Hamamoto

Subjects
Void (astronomy), Materials science, Spectrophotometry, Infrared, Scanning electron microscope, Infrared, Silicon dioxide, Analytical chemistry, 02 engineering and technology, 010502 geochemistry & geophysics, 01 natural sciences, law.invention, chemistry.chemical_compound, Optical microscope, law, Porosity, Instrumentation, Spectroscopy, 0105 earth and related environmental sciences, Diatoms, biology, Silicon Dioxide, 021001 nanoscience & nanotechnology, biology.organism_classification, Nanostructures, Amorphous solid, Diatom, chemistry, Microscopy, Electron, Scanning, 0210 nano-technology
Abstract

In order to characterize a representative natural bionanomaterial, present day centric diatom samples (diameter, 175–310 µm) have been analyzed and imaged by infrared (IR) micro-spectroscopy and scanning electron microscopy (SEM). Because diatom silica frustules have complex microscopic morphology, including many void areas such as micro- or nano-pores, the effects of voids on the spectral band shapes were first evaluated. With increasing void area percentage, 1220 cm−1/1070 cm−1 peak height ratio (Si–O polymerization index) increases and 950 cm−1/800 cm−1 peak height ratio (Si–OH/Si–O–Si) decreases, both approaching 1. Based on the void area percentage of representative diatom samples determined using SEM image analyses (51.5% to 20.5%) and spectral simulation, the 1220 cm−1/1070 cm−1 ratios of diatom samples are sometimes affected by the void effect, but the 950 cm−1/800 cm−1 ratios can indicate real structural information of silica. This void effect should be carefully evaluated for IR micro-spectroscopy of micro-nano-porous materials. Maturity of diatom specimens may be evaluated from: (1) void area percentages determined by SEM; (2) average thicknesses determined by optical microscope; and (3) average values of 1220 cm−1/1070 cm−1 peak height ratios (opposite trend to the void effect) determined by IR micro-spectroscopy. Microscopic heterogeneities of chemical structures of silica were obtained by IR micro-spectroscopic mapping of four representative diatoms. The 950 cm−1/800 cm−1 ratios show that large regions of some diatoms consist of hydrated amorphous immature silica. The successful analysis of diatoms by IR micro-spectroscopic data with careful void effect evaluation may be applied to physicochemical structures of many other bionanomaterials.

Published
2016

3. Evaluation of the effects of light intensity on growth of the benthic dinoflagellate Ostreopsis sp. 1 using a newly developed photoirradiation-culture system and a novel regression analytical method

Author

Yuya Tomori, Haruo Yamaguchi, Yuko Tanimoto, Osamu Oku, and Masao Adachi

Subjects
biology, Strain (chemistry), Dinoflagellate, Analytical chemistry, Plant Science, Aquatic Science, biology.organism_classification, Fluorescence, chemistry.chemical_compound, Light intensity, Water column, chemistry, Benthic zone, Palytoxin, Botany, Growth rate
Abstract

Benthic dinoflagellates of the genus Ostreopsis are found all over the world in temperate, subtropical, and tropical coastal regions. Our recent studies revealed that a putative “cryptic” species of Ostreopsis ovata is present widely along Japanese coasts. This organism, Ostreopsis sp. 1, possesses palytoxin analogs and thus its toxic blooms may be responsible for potential toxification of marine organisms. To evaluate the bloom dynamics of Ostreopsis sp. 1, the present study examined the growth responses of Ostreopsis sp. 1 strain s0716 to various light intensities (photon flux densities: μmol photons m −2 s −1 ) using a newly devised photoirradiation-culture system. This novel system has white light-emitting diodes (LEDs) capable of more closely simulating the wavelength spectrum of light entering the oceanic water column than do fluorescent tubes and halogen lamps. In this system, the light intensity of the white LEDs was reduced through two polarizing filters by varying the rotation angles of the filters. Thereby, the new system was capable of culturing microalgae under well-controlled light intensity conditions. Ostreopsis sp. 1 grew proportionally when light intensity was increased from 49.5 to 199 μmol photons m −2 s −1 , but its growth appeared to be inhibited slightly at ≥263 μmol photons m −2 s −1 . The relationship between observed growth rates and light intensity was calculated at R > 0.99 ( P Ostreopsis sp. 1 and the organism's growth potential as follows: (1) the threshold light intensity for growth: 29.8 μmol photons m −2 s −1 ; (2) the optimum light intensity ( L m ) giving the maximum growth rate ( μ max = 0.659 divisions day −1 ): 196 μmol photons m −2 s −1 ; (3) the optimum light intensity range ( L opt ) giving ≥95% μ max : 130–330 μmol photons m −2 s −1 ; (4) the semi-optimum range ( L sopt ) giving ≥80% μ max : 90 to over 460 μmol photons m −2 s −1 . The L sopt represents 4.5–23% ambient light intensity present in surface waters off of a temperate region of the Japanese coast, Tosa Bay; putatively, this semi-optimum range of light intensity appears at depth of 12.9–27.8 m. Considering these issues, our data indicate that Ostreopsis sp. 1 in coastal environments may form blooms at ca. ∼28 m depth in regions along Japanese coasts.

Published
2014

4. Optical discrimination of threading dislocations in 4H-SiC epitaxial layer by phase-contrast microscopy

Author

Ryuichi Sugie, Kazutsugu Murakami, Ryo Hattori, Osamu Oku, and Masaaki Kuzuhara

Subjects
010302 applied physics, Polarized light microscopy, Photoluminescence, Materials science, business.industry, General Engineering, General Physics and Astronomy, 02 engineering and technology, Edge (geometry), 021001 nanoscience & nanotechnology, Epitaxy, 01 natural sciences, Etching (microfabrication), 0103 physical sciences, Microscopy, Threading (manufacturing), Optoelectronics, 0210 nano-technology, business, Layer (electronics)
Abstract

The superior nondestructive distinguishability of threading screw dislocations and threading edge dislocations in SiC epitaxial layers by phase-contrast microscopy using our optical system was demonstrated by comparing our experimental results with those obtained by conventional polarized light microscopy, photoluminescence topography, and KOH etching. It was confirmed that phase-contrast microscopy was more effective than polarized light microscopy in terms of the nondestructive discrimination of threading dislocations.

Published
2018

5. National trends in the outcomes of subarachnoid haemorrhage and the prognostic influence of stroke centre capability in Japan: retrospective cohort study

Author

Satoshi Suzuki, Kenji Yamamoto, Hiroaki Tanaka, Hiroshi Ozawa, Yuji Okamoto, Tatsuya Abe, Hidenori Suzuki, Akiko Kada, Shigeki Nishino, Nobuyuki Sakai, Kunihiro Nishimura, Tomoyoshi Oikawa, Takanari Kitazono, Hiroshi Tanaka, Daisuke Onozuka, Akihito Hagihara, Hiroshi Ooyama, Akira Watanabe, Shinichi Yoshimura, Toru Iwama, Hiroki Sato, Satoshi Ushikoshi, Kiyohiro Houkin, Nobuhiro Mikuni, Naoyuki Nakao, Michio Nakamura, Nanako Tamiya, Naofumi Isono, Koji Iihara, Yutaka Yamaguchi, Kuniaki Ogasawara, Osamu Onodera, Yusaku Nakamura, Naoki Hayashi, Akira Takada, Hiroyuki Arai, Masayuki Ezura, Akio Hyodo, Shigeru Miyachi, Susumu Miyamoto, Yuji Matsumaru, Ichiro Nakahara, Tomoaki Terada, Kazunari Yoshida, Ai Kurogi, Ataru Nishimura, Yoshiaki Shiokawa, Koichi Arimura, Kaoru Kurisu, Fusao Ikawa, Kenji Ohata, Kyoichi Nomura, Nobuhito Saito, Hiroaki Fujiwara, Susumu Suzuki, Masanori Isobe, Soshiro Ogata, Takeshi Matsuoka, Junichiro Satomi, Takashi Matsumoto, Hiroyuki Nakase, Yasunari Niimi, Manabu Kinoshita, Mamoru Murakami, Masaaki Uno, Junichi Iida, Takashi Matsuoka, Tatsuya Sasaki, Shinichi Wakabayashi, Hiroki Toda, Hideki Sakai, Hajime Ohta, Osamu Yamamura, Hideyuki Ohnishi, Hiroko Oyama, Junichi Ono, Izumi Nagata, Hiroharu Kataoka, Ryota Kurogi, Hajime Arai, Atsuo Yoshino, Tsuyoshi Ohta, Hiroshi Sugimori, Hidehiro Hirabayashi, Hiroyuki Masaoka, Satoshi Yamamoto, Hideki Murakami, Kazuhiko Nozaki, Hiroyuki Matsumoto, Yuichiro Tanaka, Takahisa Mori, Keizo Yasui, Akira Takahashi, Ichiro Suzuki, Sachio Suzuki, TAKASHI YOSHIDA, Masanori Morimoto, Tetsuya Ueba, Hiromu Hadeishi, Masaki Chin, Michihiro Kohno, Hitoshi Fukuda, Toru Nishi, Kazunari Koga, Toshihiko Wakabayashi, Hiroki Ohkuma, Kazuhiro Hongo, Hiroshi Nakane, Kazumi Nitta, Satoshi Utsuki, Toshihiko Iuchi, Nice Ren, Hidefuku Gi, Kensuke Kawai, Masayuki Ishihara, Eiji Kohmura, Yoshihiro Nishiura, Kazutaka Yatsushiro, Kensaku Yoshida, Atsushi Tominaga, Masayuki Sumida, Hidenori Yoshida, Atsushi Sato, Takashi Inoue, Hiroaki Shimizu, Eiichiro Kamatsuka, Makoto Ichinose, Naoya Takeda, Tsuyoshi Inoue, Hidekazu Takahashi, Satoshi Kuroda, Toshiaki Osato, Nobutaka Horie, Isao Date, Yoichiro Hashimoto, Haruhiko Hoshino, Takafumi Shimogawa, Koji Yoshimoto, Teiji Tominaga, Isao Sasaki, Kazuo Kitazawa, Minoru Saitoh, Hitoshi Saito, Minoru Asahi, Makoto Goda, Atsuhito Takemura, Masaaki Shibukawa, Isao Fuwa, Saburo Watanabe, Seiko Kataoka, Koji Takasaki, Kouji Shiga, Kensuke Hayashida, Ryunosuke Uranishi, Chiaki Ito, Kenji Wakui, Takashi Saegusa, Isao Kitahara, Yasushi Ejima, Satoru Hayashi, Kazuyoshi Hattori, Shinji Okita, Toshikazu Ichihashi, Tsugumichi Ichioka, Shinichi Shirakami, Teruo Kimura, Tomonori Kobayashi, Kanehisa Kohno, Kazunori Yamanaka, Akira Morooka, Nozomi Mori, Hideo Kunimine, Masahiro Satoh, Syougo Imae, Hirochiyo Wada, Masanori Kabuto, Katsuyuki Hirakawa, Isao Inoue, Kiyoshi Kazekawa, Masani Nonaka, Kouzou Fukuyama, Shigenari Kin, Kiyoshi Saito, Yoichi Watanabe, Tadashi Arisawa, Kou Takahashi, Tetsuya Tanigawara, Junki Ito, Kei Hisada, Makoto Takeda, Jun Niwa, Mikio Nishiya, Shuji Hayashi, Ichiro Fujishima, Teiji Nakayama, Yoshihiko Watanabe, Koichirou Matsukado, Takamichi Yuguchi, Tadahisa Shono, Hiroyuki Nishimura, Jyunya Hayashi, Keisuke Migita, Kazuhiro Yokoyama, Hirotoshi Ohtaka, Takata Hisashi, Takamitsu Uchizawa, Naoki Shinohara, Mitsunobu Kaijima, Junkoh Yamamoto, Yoshio Sakagami, Hideo Aihara, Takayuki Sakaki, Keishi Fujita, Sumio Kobayashi, Nobuaki Momozaki, Masahito Hara, Akazi Kazunori, Fumitaka Miya, Hisato Minamide, Shinichiro Kurokawa, Syuichi Ishikawa, Naohisa Miura, Shinya Noda, Shoji Mashiyama, Shinji Amano, Takayuki Sugawara, Yukihiko Shimizu, Keiichi Saito, Kazuyuki Miura, Akinori Yabuta, Tatumi Yamanome, Hiroshi Seto, Makoto Hasebe, Hikaru Mizobuchi, Junkoh Sasaki, Shin Tsuruoka, Keiichi Nishimaki, Katsumi Takizawa, Hitoshi Tsugu, Nozomi Suzuki, Takeshi Kohno, Shu Hasegawa, Ken Asakura, Masaki Miyatake, Hiromu Konno, Katsunobu Takenaka, Akira Ikeda, Keizou Yamamoto, Keigo Matsumoto, Satoshi Inoha, Masaki Morisige, Kunihiko Harada, Hirofumi Hiyama, Yasuaki Takeda, Taturou Mori, Takekazu Akiyama, Osamu Okuda, Kazuaki Awamori, Naoki Shirasaki, Kimihiro Yoshino, Atsushi Shindo, Kazuho Hirahara, Shunichi Tanaka, Teruaki Kawano, Kazunori Arita, Hiroaki Sawaura, Yoichi Uozumi, Masahiko Tanaka, Shunsuke Shiraga, Shuji Sato, Mitsutoshi Nakada, Kimihisa Kinoshita, Nakazawa Kazutomo, Yasuhiro Fujimoto, Kunikazu Yoshimura, Masaaki Iwase, Shinichi Yagi, Atsushi Tsuchiya, Junichi Harashina, Sadao Kaneko, Naoto Kuwayama, Junya Hayashi, Masayuki Sasou, Sotaro Higashi, Masakazu Kitahara, Sumio Suda, Amami Kato, Satoshi Magarisawa, Kenji Hashimoto, Hirotoshi Hamaguchi, Tomohiko Satou, Masaru Idei, Haruhisa Tsukamoto, Toshihiro Kumabe, Naoaki Sato, Yasuyuki Toba, Takashi Tominaga, Haruo Yamashita, Toyoaki Shinohara, Kazuyoshi Watanabe, Hidenori Endo, Kenjirou Hujiwara, Toshinori Hasegawa, Hisashi Nitta, Kuroyanagi Takayuki, Nobuhiko Mizutani, Akira Tsunoda, Fumio Suzuki, Tetsuya Morimoto, Takuya Kawai, Mitsuyuki Fujitsuka, Hiromasa Tsuiki, Junichi Kuratsu, Hidemichi Sasayama, Shigehiro Ohmori, Seiko Hasegawa, Kazuhiro Kikuchi, Motohiro Morioka, Masayuki Yokota, Nozomu Murai, Yasumasa Yamamoto, Nobuhito Mori, Minoru Kidooka, Hiroshi Tenjin, Yoshihiro Iwamoto, Hitonori Takaba, Sei Haga, Yoshinori Arai, Toshiyuki Tsukada, Hirohide Karasudani, Masakazu Suga, Kawamoto Yukihiko, Naoto Izumi, Youtarou Takeuchi, Motohiro Arai, Shinji Okumura, Hisashi Tanaka, Yasushi Shibata, Tetsuya Masaoka, Masahiko Kasai, Hitoshi Miyake, Osamu Hamasaki, Misao Nishikawa, Naohiko Kubo, Yosimasa Kinosita, Hiroyuki Kaidu, Tarou Komuro, Hiroaki Shigeta, Yoshikazu Kusano, Shigekazu Takeuchi, Takayuki Matsuo, Yoshiharu Tokunaga, Norimoto Nakahara, Nobukazu Hashimoto, Mitsuhito Mase, Junpei Yoshimoto, Jin Momoji, Kenji Kamiyama, Koji Oka, Hiromichi Koga, Kazuya Morimoto, Tsutomu Kadekaru, Naoki Tokumitsu, Yasuyuki Nagai, Hirokazu Tanno, Takato Kagawa, Masaaki Saiki, Kotaro Ogihara, Junichi Imamura, Katsuhiro Yamashita, Akira Nakamizo, Yoshinari Nakamura, Ei-Ichirou Urasaki, Noriyuki Suzaki, Chiaki Takahashi, Youichirou Namba, Kazuo Hashikawa, Tomonori Yamada, Kazuyuki Kuwayama, Keiichi Sakai, Katsuhiro Kuroda, Hideyuki Kurihara, Masayuki Miyazono, Kosuke Miyahara, Hideaki Takahashi, Akihiko Saito, Igarashi Michitoku, Mitsuo Kouno, Shiro Kobayashi, Shunichi Yoneda, Hiroshi Kusunoki, Hiroji Miyake, Toshio Yokoe, Tatsuya Nakamura, Takayuki Kubodera, Mitsuhiko Hokari, Yasunari Otawara, Cheho Park, Hidemitu Nakagawa, Souichi Obara, Haruki Takahashi, Masafumi Ohtaki, Atsuya Okubo, Katsuhiko Hayashi, Masahisa Kawakami, Yu Takeda, Akihiko Kaga, Ryoichi Hayashi, Koji Tokunaga, Hiroyuki Nakashima, Yasuyuki Miyoshi, Atusi Kimoto, Toshimitsu Uchihara, Tomoaki Nagamine, Masahiro Noha, Hiromichi Sadashima, Toshihiko Kinjo, Osamu Tao, Masayuki Nakajima, Akira Isoshima, Kouichi Kuramoto, Shigeru Daido, Yoshiyasu Iwai, Toshihiko Kuroiwa, Akatsuki Wakayama, Kohsuke Yamashita, Yasunobu Gotou, Kouich Iwatsuki, Yoshida Masahiro, Nobuaki Kobayasi, Yoshimasa Niiya, Syouji Mabuchi, Motohiro Takayama, Kazuo Yamamoto, Junta Moroi, Masato Sugitani, Akio Ookura, Naoko Fujimura, Osamu Nishizaki, Sumio Isimaru, Hiroshi Wanihuchi, Nobukuni Murakami, Hiroto Murata, Naoki Kitagawa, Katsuhiko Kono, Michiya Kubo, Masashi Nakatsukasa, Makoto Inaba, Hidetoshi Ooigawa, Atsuhiro Kojima, Takamitsu Fujimaki, Osamu Fukuda, Yoshikazu Nakajima, Kazuyuki Kouno, Takaaki Yoshida, Reizou Kanemaru, Yohei Kudoh, Toshitaka Nakamura, Masayoshi Takigami, Shogo Nishi, Rokuya Tanikawa, Seisaburo Sakamoto, Makio Kaminogo, Seiichiro Hoshi, Yoshinari Okumura, Shinichi Okabe, Haruhiko Sato, Shiro Miyata, Kotaro Tsumura, Hiroshi Karibe, Noriaki Watabe, Ryuji Nakamura, Norifumi Shimoeda, Tsutomu Hitotsumatsu, Tomoaki Kameda, Hiroshi Ishiguchi, Atsuo Shinoda, Masanobu Hokama, Akinori Yamamura, Takeshi Kondoh, Kenichi Murao, Takafumi Wataya, Seiji Fukazawa, Shinsuke Muraoka, Hirosuke Fujisawa, Tsuneo Shishido, Mayumi Mori, Arai Hiroaki, Shinjitsu Nishimura, Zenichiro Watanabe, Susumu Nakashima, Kazuhito Nakamura, Yukinari Kakizawa, Hiroki Takano, Norihito Shirakawa, Masahiro Kagawa, Eiichiro Mabuchi, Kazusige Maeno, Takayuki Koizumi, Warou Taki, Yusuke Nakagaki, Kazuyuki Tane, Hiromichi Ooishi, Katsuyuki Asaoka, Yoshinori Akiyama, Tadao Kawamura, Atumi Takenobu, Takehisa Tuji, Masami Shimoda, Mitsunori Matsumae, Shinji Noda, Koiti Moroki, Hirofumi Oka, Masahito Agawa, Hajimu Miyake, Masateru Katayama, Shinichi Numazawa, Taketoshi Maehara, Hiroyuki Jimbo, Satoshi Ihara, Koji Matuoka, Oikawa Akihiro, Takahiro Oota, Makoto Noguchi, Takakazu Kawamata, Youichi Hashimoto, Keiichirou Onitsuka, Masahiko Kitano, Jae-Hyun Son, Toru Masuoka, Naoki Koketsu, Keiichi Akatsuka, Masamichi Kurosaki, Miyamori Tadao, Hiroaki Hondo, Kazumasa Yamatani, Hirofumi Oyama, Junji Koyama, Ogura Koichiro, Shinji Yamamoto, Hitoshi Tabata, Kazuya Uemura, Kazuhiko Sato, Hideyuki Yoshida, Takafumi Nishizaki, Hiroshi Egami, Hideo Takeshima, Shogo Ishiuchi, Akira Matsumura, Hiroyuki Kinouchi, Susumu Mekaru, Mikihiko Takeshita, Hitoshi Ozawa, Kiichiro Zenke, Takeshi Matsuyama, Toshikazu Kuwata, Teruyuki Habu, Tomoyoshi Okumura, Seiya Takehara, Rei Kondo, Takashi Kumagai, Keiten So, Sunao Takemura, Sonoda Yukihiko, Manabu Urakawa, Yasuhiro Hamada, Michiyasu Suzuki, Mikito Uchida, Hidehito Koizumi, Masaru Yamada, Takashi Tsuruno, Gen Ishida, Ryouichi Masuda, Makoto Kimura, Shinichirou Ishihara, Masashi Morikawa, Hidetoshi Murata, Katsumi Sakata, Motohiro Nomura, Akihiro Nemoto, Sumio Endou, Nobuo Hirota, Kennji Itou, Hiroaki Minami, and Yoshihumi Teramoto

Subjects
Medicine
Abstract

Objectives To examine the national, 6-year trends in in-hospital clinical outcomes of patients with subarachnoid haemorrhage (SAH) who underwent clipping or coiling and the prognostic influence of temporal trends in the Comprehensive Stroke Center (CSC) capabilities on patient outcomes in Japan.Design Retrospective study.Setting Six hundred and thirty-one primary care institutions in Japan.Participants Forty-five thousand and eleven patients with SAH who were urgently hospitalised, identified using the J-ASPECT Diagnosis Procedure Combination database.Primary and secondary outcome measures Annual number of patients with SAH who remained untreated, or who received clipping or coiling, in-hospital mortality and poor functional outcomes (modified Rankin Scale: 3–6) at discharge. Each CSC was assessed using a validated scoring system (CSC score: 1–25 points).Results In the overall cohort, in-hospital mortality decreased (year for trend, OR (95% CI): 0.97 (0.96 to 0.99)), while the proportion of poor functional outcomes remained unchanged (1.00 (0.98 to 1.02)). The proportion of patients who underwent clipping gradually decreased from 46.6% to 38.5%, while that of those who received coiling and those left untreated gradually increased from 16.9% to 22.6% and 35.4% to 38%, respectively. In-hospital mortality of coiled (0.94 (0.89 to 0.98)) and untreated (0.93 (0.90 to 0.96)) patients decreased, whereas that of clipped patients remained stable. CSC score improvement was associated with increased use of coiling (per 1-point increase, 1.14 (1.08 to 1.20)) but not with short-term patient outcomes regardless of treatment modality.Conclusions The 6-year trends indicated lower in-hospital mortality for patients with SAH (attributable to better outcomes), increased use of coiling and multidisciplinary care for untreated patients. Further increasing CSC capabilities may improve overall outcomes, mainly by increasing the use of coiling. Additional studies are necessary to determine the effect of confounders such as aneurysm complexity on outcomes of clipped patients in the modern endovascular era.

Published
2023
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6. The Distribution and Fate of Nutrients in Sagami Bay

Author

Hisae Tsuji, Osamu Oku, Yoshiaki Yamada, Akiyoshi Kamatani, and Masaru Maeda

Subjects
Nutrient, Oceanography, business.industry, Environmental science, Distribution (economics), Aquatic Science, business, Bay
Published
2000

7. Measuring biogenic silica in marine sediments

Author

Osamu Oku and Akiyoshi Kamatani

Subjects
Chemistry, Mineralogy, General Chemistry, engineering.material, Biogenic silica, Oceanography, Aluminosilicate, Illite, engineering, Environmental Chemistry, Kaolinite, Seawater, Clay minerals, Allophane, Dissolution, Water Science and Technology
Abstract

In the determination of biogenic silica (BSi) in marine sediments and suspended matter, a major difficulty is how to eliminate silica dissolved from non-BSi compounds in the samples. To overcome this, many wet chemical methods have been proposed and tested, but none have been completely acceptable. The dissolution processes of BSi, clay minerals and sediment were tested by alkaline solutions, and a more reasonable method was established which eliminates the interference of aluminosilicate compounds in the BSi determination. The BSi content was estimated through linear regression of extracted SiO2 (Y-axis) plotted as a function of extracted Al2O3 (X-axis). There was a good linear relationship between the two elements. The regression extrapolated to the Y-axis gives an intercept which can be regarded as the BSi content of the sample. However, the coexistence of amorphous aluminosilicate remains as a potential problem in the elimination of silica dissolved from the lattice.

Published
2000

8. Phospholipid in Plankton Samples from Tokyo Bay and Sagami Bay

Author

Osamu Oku and Akiyoshi Kamatani

Subjects
education.field_of_study, Ecology, Phosphorus, Population, chemistry.chemical_element, Aquatic Science, Plankton, Biology, biology.organism_classification, Zooplankton, Diatom, chemistry, Environmental chemistry, Marine ecosystem, Phosphorus cycle, education, Bay
Abstract

To evaluate the role of phospholipid in the phosphorus cycle of marine ecosystems, diatom and zooplankton samples from Tokyo Bay and Sagami Bay were used to determine phospholipid-phosphorus (phospholipid-P) and their classification. The concentration of phospholipid-P in plankton population ranged from 28.0 to 67.6μmol P/g for dry samples, corresponding 10.4 to 22.2% for the total phosphorus: Tokyo Bay samples had a higher concentration than those from Sagami Bay. In the Tokyo Bay samples, the phospholipid-P concentraions had a good correlation with the percentage of copepoda, while no correlation was found in the Sagami Bay samples. Phosphatidyicholine, phosphatidylinositol and other unknown components were isolated and identified for classification of phspholipids using silica gel chromatography, 1HNMR and gas chromatography. These phosphorus compounds were concluded to play an important role in the downward conveying systems of phosphorus in marine ecosystems.

Published
1995

9. Effects of snow compaction ‘yuki-fumi’ on soil frost depth and volunteer potato control in potato–wheat rotation system in Hokkaido

Author

Seiji Shimoda, Masayuki Onodera, Osamu Okumura, Hideharu Araki, Atsushi Kimura, Kentarou Chiba, Yuko Kusano, Harumitsu Hoshi, Shiho Tamura, Tatsuya Suda, Yasuhiro Kominami, Toshiro Nakatsuji, and Tomoyoshi Hirota

Subjects
crop rotation, volunteer potato, winter wheat, soil frost, cold region, weed control, Plant culture, SB1-1110
Abstract

Emergence of unharvested potatoes that survived during winter becomes source for nematodes and diseases, causing serious weed problems in rotational crop fields. Herein, we describe frost killing of unharvested potatoes in potato–wheat rotation fields using snow compaction ‘yuki-fumi’ under multiple climate conditions. The effect of snow compaction in controlling volunteer potato over winter wheat was verified in 17 farm fields in Hokkaido, Japan from 2015–16 to 2017–18. A reduction in the temperature of soil under ‘yuki-fumi’ was slower than that under snow removal ‘yuki-wari’, which was used in previous studies. However, snow compaction achieved a substantial reduction in volunteer potato sprouting in most of the experimental sites. The sprouting of volunteer potatoes was reduced in snow-compaction blocks with soil temperatures below −3°C. For winter wheat sowing in potato–wheat rotation, the soil is tilled to a shallower depth than that for other crops, and thus, unharvested potato tubers are not pushed down during field preparation for wheat sowing. Consequently, even if the soil temperature drops slightly, snow compaction can regulate the sprouting of volunteer potatoes. Snow compaction did not exert any apparent influence on wheat growth and grain yield. At some sites with a deeper snowpack, development of soil frost and reduction in soil temperature did not progress with continued snow compaction owing to fallen snow. We validated the usefulness of snow compaction as a countermeasure to control volunteer potatoes in snowy regions.

Published
2020
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10. Diagnostic Performance and Safety of Positron Emission Tomography Using 18F-Fluciclovine in Patients with Clinically Suspected High- or Low-grade Gliomas: A Multicenter Phase IIb Trial

Author

Toshihiko Wakabayashi, Toshihiko Iuchi, Naohiro Tsuyuguchi, Ryo Nishikawa, Yoshiki Arakawa, Takashi Sasayama, Keisuke Miyake, Tadashi Nariai, Yoshitaka Narita, Naoya Hashimoto, Osamu Okuda, Hiroshi Matsuda, Kazuo Kubota, Kimiteru Ito, Yoichi Nakazato, and Kan Kubomura

Subjects
Clinical trial, 18F-fluciclovine, Glioma, Positron emission tomography, Brain tumor, Medical physics. Medical radiology. Nuclear medicine, R895-920, Biology (General), QH301-705.5
Abstract

Objective(s): The study objective was to assess the diagnostic performance of positron emission tomography (PET) for gliomas using the novel tracer 18F-fluciclovine (anti-[18F]FACBC) and to evaluate the safety of this tracer in patients with clinically suspected gliomas.Methods: Anti-[18F]FACBC was administered to 40 patients with clinically suspected high- or low-grade gliomas, followed by PET imaging. T1-weighted, contrast-enhanced T1-weighted, and fluid-attenuated inversion recovery (or T2-weighted) magnetic resonance imaging (MRI) scans were obtained to plan for the tissue collection. Tissues were collected from either “areas visualized using anti-[18F]FACBC PET imaging but not using contrast-enhanced T1-weighted imaging” or “areas visualized using both anti-[18F]FACBC-PET imaging and contrast-enhanced T1-weighted imaging” and were histopathologically examined to assess the diagnostic accuracy of anti-[18F]FACBC-PET for gliomas.Results: The positive predictive value of anti-[18F]FACBC-PET imaging for glioma in areas visualized using anti-[18F]FACBC-PET imaging, but not visualized using contrast-enhanced T1- weighted images, was 100.0% (26/26), and the value in areas visualized using both contrastenhanced T1-weighted imaging and anti- [18F]FACBC-PET imaging was 87.5% (7/8). Twelve adverse events occurred in 7 (17.5%) of the 40 patients who received anti-[18F]FACBC. Five events in five patients were considered to be adverse drug reactions; however, none of the events were serious, and all except one resolved spontaneously without treatment.Conclusion: This Phase IIb trial showed that anti-[18F]FACBC-PET imaging was effective for the detection of gliomas in areas not visualized using contrast-enhanced T1-weighted MRI and the tracer was well tolerated.

Published
2017
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11. Optical discrimination of threading dislocations in 4H-SiC epitaxial layer by phase-contrast microscopy.

Author

Ryo Hattori, Osamu Oku, Ryuichi Sugie, Kazutsugu Murakami, and Masaaki Kuzuhara

Abstract

The superior nondestructive distinguishability of threading screw dislocations and threading edge dislocations in SiC epitaxial layers by phase-contrast microscopy using our optical system was demonstrated by comparing our experimental results with those obtained by conventional polarized light microscopy, photoluminescence topography, and KOH etching. It was confirmed that phase-contrast microscopy was more effective than polarized light microscopy in terms of the nondestructive discrimination of threading dislocations. [ABSTRACT FROM AUTHOR]

Published
2018
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12. Infrared Microspectroscopy of Bionanomaterials (Diatoms) with Careful Evaluation of Void Effects.

Author

Leila Alipour, Mai Hamamoto, Satoru Nakashima, Rika Harui, Masanari Furiki, and Osamu Oku

Subjects
*DIATOMS, *INFRARED spectroscopy, *VOIDS (Crystallography), *SILICA, *NANOSTRUCTURED materials
Abstract

In order to characterize a representative natural bionanomaterial, present day centric diatom samples (diameter, 175-310 μm) have been analyzed and imaged by infrared (IR) micro-spectroscopy and scanning electron microscopy (SEM). Because diatom silica frustules have complex microscopic morphology, including many void areas such as micro- or nanopores, the effects of voids on the spectral band shapes were first evaluated. With increasing void area percentage, 1220 cm-1/1070cm-1 peak height ratio (Si-O polymerization index) increases and 950 cm-1/800 cm-1 peak height ratio (Si-OH/Si-O-Si) decreases, both approaching 1. Based on the void area percentage of representative diatom samples determined using SEM image analyses (51.5% to 20.5%) and spectral simulation, the 1220 cm-1/1070 cm-1 ratios of diatom samples are sometimes affected by the void effect, but the 950 cm-1/800 cm-1 ratios can indicate real structural information of silica. This void effect should be carefully evaluated for IR micro-spectroscopy of micro-nano-porous materials. Maturity of diatom specimens may be evaluated from: (1) void area percentages determined by SEM; (2) average thicknesses determined by optical microscope; and (3) average values of 1220 cm-1/1070 cm-1 peak height ratios (opposite trend to the void effect) determined by IR micro-spectroscopy. Microscopic heterogeneities of chemical structures of silica were obtained by IR micro-spectroscopic mapping of four representative diatoms. The 950 cm-1/800 cm-1 ratios show that large regions of some diatoms consist of hydrated amorphous immature silica. The successful analysis of diatoms by IR micro-spectroscopic data with careful void effect evaluation may be applied to physicochemical structures of many other bionanomaterials. [ABSTRACT FROM AUTHOR]

Published
2016
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