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61.
T Matsuno K Maruyama J Tsutsui 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2012,88(7):368-384
The concept of "stabilization" of atmospheric CO2 concentration is re-examined in connection with climate-change mitigation strategies. A new "zero-emissions stabilization (Z-stabilization)" is proposed, where CO2 emissions are reduced to zero at some time and thereafter the concentration is decreased by natural removal processes, eventually reaching an equilibrated stable state. Simplified climate experiments show that, under Z-stabilization, considerably larger emissions are permissible in the near future compared with traditional stabilization, with the same constraint on temperature rise. Over longer time scales, the concentration and temperature decrease close to their equilibrium values, much lower than those under traditional stabilization. The smaller temperature rise at final state is essential to avoid longer-term risk of sea level rise, a significant concern under traditional stabilization. Because of these advantages a Z-stabilization pathway can be a candidate of practical mitigation strategies as treated in Part 2.(Contributed by Taroh MATSUNO, M.J.A.). 相似文献
62.
Yasushi Kanai Yoshihiro JinboKazuya Koyama Kazuetsu YoshidaSimon Greaves Hiroaki Muraoka 《Journal of magnetism and magnetic materials》2012,324(3):282-286
Landau-Lifshitz-Gilbert micromagnetic models were used to analyze the head field distributions and high-frequency responses for various soft magnetic underlayer thicknesses (t-SUL) and saturation magnetization flux densities (Bs) of single-pole-type (SPT) head-SUL systems. It was found that Bs of 10-12 kG and t-SUL of 30-45 nm would be sufficient for the examined head and perhaps for most next generation head-SUL systems. Antiferromagnetic coupling in the SUL affects the head and SUL magnetization and, eventually, the head field. With regard to the head magnetization response, it was found that the magnetization under the coil responded first, while the response at the main pole tip was quite slow, even compared with the head field. The main pole tip of the head was fully saturated and the main pole yoke was almost saturated, while the SUL was not saturated in the examined head-SUL system. 相似文献
63.
Atsuya Ishida Prof. Go Watanabe Dr. Mio Oshikawa Prof. Itsuki Ajioka Prof. Takahiro Muraoka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(59):13523-13530
Self-assembling peptides that are capable of adopting β-sheet structures can generate nanofibers that lead to hydrogel formation. Herein, to tune the supramolecular morphologies, mechanical properties, and stimuli responses of the hydrogels, we investigated glycine substitution in a β-sheet-forming amphiphilic peptide. Glycine substitution generally enhances conformational flexibility. Indeed, glycine substitution in an amphiphilic peptide weakened the hydrogels or even inhibited the gelation. However, unexpectedly, glycine substitution at the center of the peptide molecule significantly enhanced the hydrogel stiffness. The central glycine substitution affected the molecular packing and led to twisted β-sheet structures and to nanofiber bundling, which likely led to the stiffened hydrogel. Importantly, the supramolecular structures were accurately predicted by molecular dynamics simulations, demonstrating the helpfulness of these techniques for the identification of self-assembling peptides. The hydrogel formed by the amphiphilic peptide with the central glycine substitution had cell adhesive function, and showed a reversible thermal gel-to-sol transition. Thus, glycine substitution is effective in modulating self-assembling structures, rheological properties, and dynamics of biofunctional self-assembling peptides. 相似文献
64.
Koki Kise Prof. Dr. Atsuhiro Osuka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(68):15493-15497
B-Phenyl BIII subporphyrin-α-diones prepared in a three-step reaction sequence from the parent subporphyrin were condensed with 1,2-diaminobenzenes to give the corresponding quinoxaline-fused subporphyrins in variable yields. Quinoxaline-fused B-phenyl-5,10,15-triphenyl BIII subporphyrin was transformed to the corresponding subporphyrin-α-dione in the same three-step reaction sequence, which was then condensed with 1,2-diaminobenzene to give doubly quinoxaline-fused subporphyrin. These quinoxaline-fused subporphyrins exhibit redshifted absorption and fluorescence spectra compared with the parent one. A singly quinoxaline-fused subporphyrin bearing three meso-bis(4-dimethylaminophenyl)aminophenyl substituents shows blueshifted fluorescence in less polar solvent, which has been ascribed to emission associated with charge recombination of intramolecular charge transfer (CT) state. 相似文献
65.
Dr. Yosuke Hisamatsu Koki Otani Hiroshi Takase Dr. Naoki Umezawa Prof. Dr. Tsunehiko Higuchi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(21):6489-6499
There is increasing interest in the development and applications of synthetic receptors that recognize target biomolecules in aqueous media. We have developed a new tweezer-type synthetic receptor that gives a significant fluorescence response upon complexation with heme in aqueous solution at pH 7.4. The synthetic receptor consists of a tweezer-type heme recognition site and sulfo-Cy5 as a hydrophilic fluorophore. The receptor–heme complex exhibits a supramolecular amphiphilic character that facilitates the formation of self-assembled aggregates, and both the tweezer moiety and the sulfo-Cy5 moiety are important for this property. The synthetic receptor also exhibits significant fluorescence responses to biliverdin and bilirubin, but shows very weak fluorescence responses to flavin mononucleotide, folic acid, and nicotinamide adenine dinucleotide, which contain smaller π-scaffolds. 相似文献
66.
Fluctuating Carbonaceous Networks with a Persistent Molecular Shape: A Saddle‐Shaped Geodesic Framework of 1,3,5‐Trisubstituted Benzene (Phenine) 下载免费PDF全文
Dr. Koki Ikemoto Jennie Lin Ryo Kobayashi Dr. Sota Sato Prof. Dr. Hiroyuki Isobe 《Angewandte Chemie (International ed. in English)》2018,57(28):8555-8559
A saddle‐shaped macromolecule has been synthesized. The molecule was designed as a geodesic saddle with 1,3,5‐trisubstituted benzene (named phenine) as the fundamental unit. The phenines were woven into a polygonal framework that was composed of 168 sp2‐hybridized carbon atoms. The saddle‐shaped structure with unique symmetry showed atypical conformational changes. The biaryl linkages in this molecule had a small energy barrier for rotation, and these structural fluctuations resulted in seven 1H NMR resonances representing 84 aromatic hydrogen atoms. Nevertheless, the overall saddle shape of the molecule was persistent, and the “up” and “down” orientations of phenine moieties circulated to give average 1H resonances. The structural characteristics of this molecule, including the anomalous entropy‐driven dimerization, may deepen our understanding of defect‐rich graphitic sheets. 相似文献
67.
Toshio Ito Nobuya Tomiyoshi Koki Nakamura Shizuo Azuma Makoto Izawa Fumio Maruyama Mitsutoshi Yanagiya Haruhisa Shirahama Takeshi Matsumoto 《Tetrahedron》1984,40(1):241-255
The total synthesis of dl-coriolin has been achieved in a stereoselective way. The key tricyclic intermediate was synthesized from dicyclopentadiene through a route which involved an SN2 reaction at a neopentylic position. 相似文献
68.
A potent ACAT (acyl-CoA: cholesterol acyltransferase) inhibitor SMP-797 was effectively synthesized by the urea formation of 3-amino-4-aryl-1,8-naphthyridin-2(1H)-one and 4-amino-2,6-diisopropylamine. The synthesis of the former compound involved the Suzuki coupling reaction as a key step, and the latter was prepared by the 4-selective nitration of 2,6-diisopropylaniline using 2,3,5,6-tetrabromo-4-methyl-4-nitro-2,5-cyclohexadienone. 相似文献
69.
Dr. Mitsuhiko Morisue Ikuya Ueno Kunihiko Muraoka Dr. Shun Omagari Dr. Takayuki Nakanishi Prof. Yasuchika Hasegawa Dr. Takaaki Hikima Prof. Sono Sasaki 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(30):7322-7329
Quadrupolar interactions of porphyrin bearing two pentafluorophenylethynyl terminals ( 1 ) drove the formation of a successive one-dimensional staircase structure, i.e., J-aggregates, to yield millimeter-length needles with a single-crystalline character in methylcyclohexane solution. In contrast, π-stacked interactions of porphyrin bearing two nonfluorinated phenyl terminals ( 2 ) formed no aggregates in solution. A spin-cast film of 1 also showed bathochromic shift of the Soret and Q bands, indicating the formation of J-aggregates. The molecular arrangement of the J-aggregates was revealed by microbeam glazing-incidence wide-angle X-ray diffraction (GIWAXD), and was in good agreement with the optimized structure generated by density functional theory (DFT) calculations. 相似文献
70.
Effect of intergranular exchange coupling in coupled granular and continuous (CGC) perpendicular media was investigated in terms of improvement of signal-to-noise ratio (SNR). The exchange coupling improves SNR and byte error rate (BER); however, it tended to widen the magnetic track width (MWW) of a track. That degradation is of concern for the CGC media. This paper discusses intergranular exchange coupling in CGC media to optimize track density and linear density to achieve high areal density. 相似文献