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101.
Masataka Kubo Hisatomu Yamamoto Takahiro Uno Takahito Itoh Hiroaki Sato 《Polymer Bulletin》2001,47(1):25-30
Summary
α-Amino, ω-carboxyl heterodifunctional poly(methyl methacrylate) was prepared by a living anionic polymerization of methyl
methacrylate using N,N'-diphenylethylenediamine monolithium amide and succinic anhydride as an initiator and terminator, respectively. Its intramolecular
cyclization was carried out to obtain a well-defined cyclic poly(methyl methacrylate).
Received: 27 June 2001/Accepted: 16 July 2001 相似文献
102.
Takahiro Matsumoto Tetsuro Nose Yasuaki Nagata Katsuhiro Kawashima Tastuya Yamada Hidetoshi Nakano Satoshi Nagai 《Journal of the American Ceramic Society》2001,84(7):1521-1525
Young's modulus and Poisson's ratio of SiC ceramics at temperatures >1400°C were obtained using a laser ultrasonics method that included a Fabry-Pérot interferometer (LUFP). At temperatures <1000°C, Young's modulus and Poisson's ratio measured using the LUFP method agreed well with those measured using standard contact methods, such as the resonance method and the ultrasonic pulse method. These results showed that the LUFP method is a powerful tool for measuring high-temperature elastic properties of advanced ceramics in a noncontact manner. 相似文献
103.
Meng Guo Masakoto Kanezashi Hiroki Nagasawa Liang Yu Kazuki Yamamoto Takahiro Gunji Toshinori Tsuru 《American Institute of Chemical Engineers》2020,66(4):e16850
Fine-tuned, molecular-composite, organosilica membranes were fabricated via the co-condensation of organosilica precursors bis(triethoxysilyl)acetylene (BTESA) and bis(triethoxysilyl)benzene (BTESB). Fourier transform infrared and UV–vis spectra confirmed the co-condensation behaviors of BTESA and BTESB. The evolution of the network structure indicated that the incorporated BTESB decreased the membrane pore size, which was determined by a modified gas translation model according to the steric effect of the phenyl groups. The incorporation of BTESB to BTESA finely tuned the membrane structure and endowed the resultant composite membrane with improved separation properties. The BTESAB 9:1 membrane (molar ratio of BTESA/BTESB was 9:1) exhibited high C3H6 permeance at 4.5 × 10−8 mol m−2 s−1 Pa−1 and a C3H6/C3H8 permeance ratio of 33 at 50°C. One of the most important developments of this study involved clearly defining the relationship between membrane pore size and C3H6/C3H8 separation performance for organosilica membranes in single and binary separation systems. 相似文献
104.
The characterization of the interfacial surface of a dimethoxysilyl‐terminated polypropylene oxide (DMSi–PPO)/diglycidylether of bisphenol A (DGEBA) system, which has the phase structure of DGEBA particles in a DMSi–PPO matrix, was investigated by using model joints with polymeric substrates. The surface free energy (γ) of the DMSi–PPO/DGEBA system had varied with the γ of each substrate. When the system contacted to low surface free energy materials such as Teflon, polypropylene, and polyethylene, the γ of the system showed about 14.3–31.6 mJ/m2; on the other hand, when the system contacted to high surface free energy substrates such as polyethylene–telephthalate and polyimide, the γ of the system showed 50.4 and 64.6 mJ/m2, respectively, because the concentration of the DGEBA as a polar component in the system changed around these interfaces. In the low surface energy substrates used, the actual peel adhesion energy value was in good agreement with the thermodynamic work of adhesion (Wa) determined independently. However, in the high surface energy materials used, the peel adhesion energies were 103–104 times larger than Wa because the energy was dissipated viscoelastically at the jointed points. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1920–1930, 2001 相似文献
105.
Liposome‐Based in Vitro Evolution of Aminoacyl‐tRNA Synthetase for Enhanced Pyrrolysine Derivative Incorporation 下载免费PDF全文
Dr. Atsuko Uyeda Dr. Takayoshi Watanabe Dr. Yasuhiko Kato Prof. Hajime Watanabe Prof. Tetsuya Yomo Prof. Takahiro Hohsaka Dr. Tomoaki Matsuura 《Chembiochem : a European journal of chemical biology》2015,16(12):1797-1802
Methanosarcina species pyrrolysyl‐tRNA synthetase (PylRS) attaches Pyl to its cognate amber suppressor tRNA. The introduction of two mutations (Y384F and Y306A) into PylRS was previously shown to generate a mutant, designated LysZ‐RS, that was able to attach N‐benzyloxycarbonyl‐L ‐lysine (LysZ) to its cognate tRNA. Despite the potential of LysZ derivatives, further LysZ‐RS engineering has not been performed; consequently, we aimed to generate LysZ‐RS mutants with improved LysZ incorporation activity through in vitro directed evolution. Using a liposome‐based in vitro compartmentalization (IVC) approach, we screened a randomly mutagenized gene library of LysZ‐RS and obtained a mutant that showed increased LysZ incorporation activity both in vitro and in vivo. The ease and high flexibility of liposome‐based IVC should enable the evolution of not only LysZ‐RS that can attach various LysZ derivatives but also of other enzymes involved in protein translation. 相似文献
106.
Akon Higuchi Boo Ok Yoon Takayuki Kaneko Mariko Hara Maya Maekawa Takashi Nohmi 《应用聚合物科学杂志》2004,94(4):1737-1742
We examined the existence of endocrine disruptors in mineral water, ultrapure water, and tap water. GC/MS analysis revealed that dioctylphthalate (di‐n‐octylphthalate and di(2‐ethylhexyl)phthalate) in the water was found to be on the order of parts per billion. The dioctylphthalate concentration remained consistent for mineral water of the same brand, regardless of whether it was bottled in a PET bottle or a glass bottle. Therefore, the dioctylphthalate contamination in mineral water originated from the manufacturing line of the mineral water and not as a result of leaching from PET bottles. Butylated hydroxytoluene (BHT), an oxidization prevention agent in plastics, was detected at 2.05 ± 0.1 ppb in the mineral water bottled in glass bottles, but was not detected in the mineral water bottled in PET bottles. BHT contamination in the mineral water in the glass bottles is likely to have originated from the cap of the glass bottles, as the caps were sealed with polyethylene. We further investigated the feasibility of separating dioctylphthalate and BHT from the mineral water by pervaporation using hydrophobic polydimethylsiloxane membranes. We found that trace amounts (on the order of parts per billion) of organic chemicals such as dioctylphthalate and BHT in aqueous solutions can be removed and concentrated by the pervaporation using polydimethylsiloxane membranes. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1737–1742, 2004 相似文献
107.
G‐Quadruplexes with Tetra(ethylene glycol)‐Modified Deoxythymidines are Resistant to Nucleases and Inhibit HIV‐1 Reverse Transcriptase 下载免费PDF全文
108.
Ming Zhou Hidetaka Hara Yifan Dai Lisha Mou David K. C. Cooper Changyou Wu Zhiming Cai 《International journal of molecular sciences》2016,17(8)
Different cell types possess different miRNA expression profiles, and cell/tissue/organ-specific miRNAs (or profiles) indicate different diseases. Circulating miRNA is either actively secreted by living cells or passively released during cell death. Circulating cell/tissue/organ-specific miRNA may serve as a non-invasive biomarker for allo- or xeno-transplantation to monitor organ survival and immune rejection. In this review, we summarize the proof of concept that circulating organ-specific miRNAs serve as non-invasive biomarkers for a wide spectrum of clinical organ-specific manifestations such as liver-related disease, heart-related disease, kidney-related disease, and lung-related disease. Furthermore, we summarize how circulating organ-specific miRNAs may have advantages over conventional methods for monitoring immune rejection in organ transplantation. Finally, we discuss the implications and challenges of applying miRNA to monitor organ survival and immune rejection in allo- or xeno-transplantation. 相似文献
109.
Takahiro Ohkubo Eiji Tsuchida Kenzo Deguchi Shinobu Ohki Tadashi Shimizu Toshiya Otomo Yasuhiko Iwadate 《Journal of the American Ceramic Society》2018,101(3):1122-1134
It remains a challenge to establish structural models of multicomponent oxide glass systems. In this study, we have investigated 68.3SiO2–16.1B2O3–4.2Al2O3–11.4Na2O glass and melt structures by ab initio molecular dynamics (AIMD) simulations. The atomic configurations obtained from AIMD simulations were validated against 17O solid‐state NMR spectrum under 24.0 T and neutron diffraction data, and excellent agreement was achieved. The bond lengths, angles, and coordination geometries were statistically analyzed for each atomic species. Here we particularly address the role of minor atomic species such as five‐coordinate Si (SiV) and Al (AlV). The SiV–O bond lengths and O–SiV–O angle distribution in the glass indicated 1.718 Å and three peaks at 90°, 120°, and 175°, which are assigned to a coordination geometry of the trigonal bipyramidal structure. Ring statistic analysis revealed that SiV and AlV were found to preferentially contribute to the formation of small ring sizes. 相似文献
110.
Coals of different ranks were acid-treated in aqueous methoxyethoxy acetic acid (MEAA), acetic acid (AA), and HCl. The acid-treated coals were extracted with polar N-methyl-2-pyrrolidinone (NMP) and nonpolar 1-methylnaphthalene (1MN) solvents at temperatures from 200 to 360 °C for 10-60 min. The thermal extraction yields with NMP for some acid-treated low-rank coals increased greatly; for example, the extraction yield for Wyodak coal (%C; 75.0%) increased from 58.4% for the raw coal to 82.9% for coal treated in 1.0 M MEAA. Conversely, the extraction yields changed minimally for all the acid-treated coals extracted in 1-MN. The type and concentration of acid affected the extraction yield when NMP was used as the extraction solvent. With increasing MEAA concentration from 0.01 to 0.1 M, the extraction yield for Wyodak coal increased from 66.3 to 81.4%, and subsequently did not change clearly with concentration. Similar changes in the extraction yield with acid concentration were also observed with AA and HCl. The de-ashing ratio for coals acid-treated in MEAA, AA, and HCl also increased greatly with concentration from 0.01 to 0.1 M, which corresponded to the change in the thermal extraction yield in NMP. For the acid-treated coals, high extraction yields were obtained at lower extraction temperatures and shorter extraction times than for the raw coal. The mechanisms for the acid treatment and thermal extraction are discussed. 相似文献