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- 저자 : Fukui, Akihiko (검색결과 237 건)
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Porphyrin Arch-Tapes: Synthesis, Contorted Structures, and Full Conjugation
Fukui, Norihito,Kim, Taeyeon,Kim, Dongho,Osuka, Atsuhiro American Chemical Society 2017 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.139 No.26
<P>Porphyrin tapes possessing meso-meso beta-beta beta-beta triple direct linkages have been targets of extensive studies because of their fully conjugated characteristic pi-electronic networks. In this paper, we report porphyrin arch tapes that bear additional carbonyl group(s) or methylene group(s) inserted between one of the beta-beta linkage(s) of the porphyrin tapes. The carbonyl-inserted porphyrin arch-tapes were efficiently synthesized by double fusion reactions of beta-to-beta carbonyl-bridged porphyrin oligomers with DDQ and Sc(OTf)(3), and were converted to the methylene-bridged porphyrin arch-tapes via Luche reduction with NaBH4 and CeCl3 followed by ionic hydrogenation with HBF4 center dot OEt2 and BH3 center dot NEt3. While the conventional porphyrin tapes display rigid and planar structures and low solubilities, these porphyrin arch-tapes show remarkably contorted structures, flexible conformations, and improved solubilities because of the presence of the incorporated seven-membered ring(s). Interestingly, the methylene inserted arch-tapes exhibited conjugative electronic interactions that were comparable to those of porphyrin tapes probably owing to through-space interaction in the contorted conformations. The carbonyl-inserted arch-tapes displayed distinctly larger conjugative interactions owing to an active involvement of the carbonyl group(s) in the electronic conjugation. A similar trend was observed in the nonlinear optical properties, as evidenced by their two-photon absorption cross sections. Furthermore, as a benefit of the contorted structures, these porphyrin arch-tapes can catch C-60 fullerene effectively. Naturally, the electron-rich methylene-bridged arch-tapes exhibited larger association constants than the electron-deficient carbonyl-bridged arch-tapes. Among these arch-tapes, a methylene-bridged syn-Ni(II) porphyrin trimer recorded the largest association constant of (1.5 +/- 0.4) X 10(7) M-1 in toluene at 25 degrees C.</P>
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Fukui Ryohei,Miho Numata,Saki Nishioka,Ryutarou Matsuura,Katsuhiro Kida,Sachiko Goto 한국의학물리학회 2022 의학물리 Vol.33 No.4
Purpose: To clarify the relationship between the diameter of the simulated bead and the Z-resolution of the tomosynthesis image. Methods: A simulated bead was placed on a 1,024×1,024×1,024-pixel base image. The diameters were set to 0.025, 0.05, 0.1, 0.2, 0.3, 0.7, 1.0, and 1.3 mm. A bead was placed at the center of the base image and projected at a simulated X-ray angle range of ±45° to obtain a projected image. A region of interest was placed at the center of the bead image and the slice sensitivity profile (SSP) was obtained by acquiring pixel values in the z-direction. The full width at half maximum of the SSP was defined as the Z-resolution and the frequency response was obtained by the 1-D Fourier transform of the SSP. Results: Z-resolution increased with increasing bead diameter. However, there was no change in Z-resolution between 0.025 and 0.1 mm. The frequency response was similar to that of the Z-resolution, with a significant difference between 0.1 and 0.2 mm diameter. Conclusions: Z-resolution is dependent on the diameter of the bead, which should be selected considering the pixel size of the tomosynthesis image.
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Effect of the Number of Projected Images on the Noise Characteristics in Tomosynthesis Imaging
Fukui, Ryohei,Matsuura, Ryutaro,Kida, Katsuhiro,Goto, Sachiko Korean Society of Medical Physics 2021 의학물리 Vol.32 No.2
Purpose: In this study, we investigated the relationship between the noise characteristics and the number of projected images in tomosynthesis using a digital phantom. Methods: The digital phantom consisted of a columnar phantom in the center of the image and a spherical phantom with a diameter of 80 pixels. A virtual scan was performed, and 128 projected images (Tomo_w/o) of the phantoms were obtained. The image noise according to the Poisson distribution was added to the projected images (Tomo_×1). Furthermore, another projected image with additional noise was prepared (Tomo_×1/2). For each dataset, we created datasets with 64 (half) and 32 (quarter) projections by removing the even-numbered images twice from the 128 (fully) projected images. Tomosynthesis images were reconstructed by filtered back projection (FBP). The modulation transfer function (MTF) was estimated using the sphere method, and the noise power spectrum (NPS) was estimated using the two-dimensional Fourier transform method. Results: The MTFs did not change between datasets, and the NPSs improved as the number of projected images increased. The noise characteristics of the Tomo_×1_half images were the same as those of the Tomo_×1/2_full. Conclusions: To achieve a reduction in the patient dose in tomosynthesis acquisition, we recommend reducing the number of projected images rather than reducing the dose per projection.
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Analysis of the Formation of Protoplasts and Regeneration of Cells in Phycomyces blakesleeanus
Fukui, Joe,Choi, Kwan Sam,Miyazaki, Atsushi,Ootaki, Tamotsu,Oikawa, Taneaki 한국미생물 · 생명공학회 2001 Journal of microbiology and biotechnology Vol.11 No.1
It is possible to prepare protoplasts of the zygomycete fungus, Phycomyces blakesleeanus, by digesting the cell wall of spore germlings with commercially available chitinase and chitosanase. However, the cells without any cell walls immediately form large aggregates, and thus, it is difficult to isolate the individually separated protoplasts. Inherent problem with the formation of aggregates in preparing protoplasts could be solved by the use of bovine serum albumin (BSA). As a result, we were able to prepare a large number of single protoplasts quickly and easily. We took time-lapse photomicrographs of the formation of protoplasts, and found that there were certain regions of the cell wall of spore germlings that were sensitive to chitinase and chitosanase, although the cell wall of the original spores is known to be insensitive to these enzymes. There are two kinds of cell walls on a spore germling; one with a bound wheat germ agglutinin (WGA), and the other a bound concanavalin A (ConA). Furthermore, only cells with walls which had bound WGA were able to regenerate, while those with walls with bound ConA were not able to regenerate.
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Fukui, Sei,Nitta, Kazuhito,Iwashita, Narihito,Tomie, Hisashi,Nosaka, Shuichi,Rohof, Olav The Korean Pain Society 2012 The Korean Journal of Pain Vol.25 No.3
Background: We have developed an intradiscal pulsed radiofrequency (Disc PRF) technique, using Diskit $II^{(R)}$ needles (NeuroTherm, Wilmington, MA, USA), as a minimally invasive treatment option for chronic discogenic low back pain (LBP). The purpose of this study was to compare the representative outcomes of Disc PRF and Intradiscal Electrothermal Therapy (IDET) in terms of pain relief and reduction of disability. Methods: Thirty-one patients with chronic discogenic LBP who underwent either Disc PRF (n = 15) or IDET (n = 16) were enrolled in the study. A Diskit $II^{(R)}$ needle (15-cm length, 20-gauge needle with a 20-mm active tip) was placed centrally in the disc. PRF was applied for 15 min at a setting of $5{\times}50$ ms/s and 60 V. The pain intensity score on a 0-10 numeric rating scale (NRS) and the Roland-Morris Disability Questionnaire (RMDQ) were assessed pretreatment and at 1, 3, and 6 months post-treatment. Results: The mean NRS was significantly improved from $7.2{\pm}0.6$ pretreatment to$2.5{\pm}0.9$ in the Disc PRF group, and from $7.5{\pm}1.0$ to $1.7{\pm}1.5$ in the IDET group, at the 6-month follow-up. The mean RMDQ also showed significant improvement in both the Disc PRF group and the IDET group at the 6-month follow-up. There were no significant differences in the pretreatment NRS and RMDQ scores between the groups. Conclusions: Disc PRF appears to be an alternative to IDET as a safe, minimally invasive treatment option for patients with chronic discogenic LBP.
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Fukui, Norihito,Lee, Seung-Kyu,Kato, Kenichi,Shimizu, Daiki,Tanaka, Takayuki,Lee, Sangsu,Yorimitsu, Hideki,Kim, Dongho,Osuka, Atsuhiro Royal Society of Chemistry 2016 Chemical science Vol.7 No.7
<▼1><P>Oxidation of 10,15,20-triaryl Ni(<SMALL>II</SMALL>)-porphyrins bearing an electron-withdrawing substituent at the 5-position with DDQ and FeCl<SUB>3</SUB> gave 10,12- and 18,20-doubly phenylene-fused Ni(<SMALL>II</SMALL>)-porphyrins regioselectively.</P></▼1><▼2><P>Oxidation of 10,15,20-triaryl Ni(<SMALL>II</SMALL>)-porphyrins bearing an electron-withdrawing substituent at the 5-position with DDQ and FeCl<SUB>3</SUB> gave 10,12- and 18,20-doubly phenylene-fused Ni(<SMALL>II</SMALL>)-porphyrins regioselectively. A doubly phenylene-fused <I>meso</I>-chloro porphyrin thus prepared was reductively coupled to give a <I>meso</I>–<I>meso</I> linked dimer, which was further converted to a quadruply phenylene-fused <I>meso</I>–<I>meso</I>, β–β, β–β triply linked Zn(<SMALL>II</SMALL>)–diporphyrin <I>via</I> inner-metal exchange followed by oxidation with DDQ and Sc(OTf)<SUB>3</SUB>. As compared to the usual <I>meso</I>–<I>meso</I>, β–β, β–β triply linked Zn(<SMALL>II</SMALL>)-diporphyrin, this π-extended porphyrin dyad exhibits a smaller HOMO–LUMO gap and a larger two-photon absorption cross-section.</P></▼2>
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Tongguk chŏngun and the Phonological System of Middle Korean
Fukui Rei 훈민정음학회 2012 Scripta Vol.0 No.4
This paper discusses how the reformed system of Sino-Korean, Tongguk chŏngun, was accommodated into the phonological system of Middle Korean. Tongguk chŏngun readings of characters are usually regarded as artificial but in this paper it is emphasized that they were expected to be learnt and correctly pronounced by everyone who wished to learn the newly created alphabet. By examining various seemingly artificial elements such as entering tone ending -rq, geminate consonants, vowels including a rounded palatal medial sound and so on, it is concluded that the system of Tongguk chŏngun uses only those sounds that are already existing in the native Korean vocabulary, thereby tolerating the constraints on the possible position of occurrence.
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Fukui, Y.,Kawamura, A.,Wong, T.,Murai, M.,Iritani, H.,Mizuno, N.,Mizuno, Y.,Onishi, T.,Hughes, A.,Ott, J.,Muller, E.,Staveley-Smith, L.,Kim, S. IOP Publishing 2009 The Astrophysical journal Vol.705 No.1
<P>We compare the CO (J = 1-0) and HI emission in the Large Magellanic Cloud in three dimensions, i.e., including a velocity axis in addition to the two spatial axes, with the aim of elucidating the physical connection between giant molecular clouds (GMCs) and their surrounding Hi gas. The CO J = 1-0 data set is from the second NANTEN CO survey and the HI data set is from the merged Australia Telescope Compact Array ( ATCA) and Parkes Telescope surveys. The major findings of our analysis are as follows: (1) GMCs are associated with an envelope of HI emission, (2) in GMCs [average CO intensity] proportional to [ average Hi intensity](1.1 +/- 0.1), and (3) the HI intensity tends to increase with the star formation activity within GMCs, from Type I to Type III. An analysis of the HI envelopes associated with GMCs shows that their average line width is 14 km s(-1) and the mean density in the envelope is 10 cm(-3). We argue that the HI envelopes are gravitationally bound by GMCs. These findings are consistent with a continual increase in the mass of GMCs via HI accretion at an accretion rate of 0.05 M-circle dot yr(-1) over a timescale of 10 Myr. The growth of GMCs is terminated via dissipative ionization and/or stellar-wind disruption in the final stage of GMC evolution.</P>
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