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231.
Natural supramolecular assemblies exhibit unique structural and functional properties that have been optimized over the course of evolution. Inspired by these natural systems, various bio‐nanomaterials have been developed using peptides, proteins, and nucleic acids as components. Peptides are attractive building blocks because they enable the important domains of natural protein assemblies to be isolated and optimized while retaining the original structures and functions. Furthermore, the peptide subunits can be conjugated with exogenous molecules such as peptides, proteins, nucleic acids, and metal nanoparticles to generate advanced functions. In this personal account, we summarize recent progress in the construction of peptide‐based nanomaterial designed from natural supramolecular systems, including (1) artificial viral capsids, (2) self‐assembled nanofibers, and (3) protein‐binding motifs. The peptides inspired by nature should provide new design principles for bio‐nanomaterials. 相似文献
232.
Yamashita M Inaba T Nagahama M Shimizu T Kosaka S Kawasaki I Ohta S 《Organic & biomolecular chemistry》2005,3(12):2296-2304
1,2a-Disubstituted 1,2,2a,8b-tetrahydro-3H-benzo[b]cyclobuta[d]pyran-3-ones bearing an electron-withdrawing group at the 2a-position were treated with two equivalents of dimethylsulfoxonium methylide to give r-1,t-4a,t-9b-1,3-disubstituted 1,2,4a,9b-tetrahydrodibenzofuran-4-ols stereoconvergently regardless of the stereochemistry of the 1-position on the benzocyclobutapyran ring. This methodology was applied to the second-generation synthesis of (+/-)-linderol A, a melanin biosynthesis inhibitory natural product. 相似文献
233.
Ryoji Inaba Takayuki Fukahori Masato Hamamoto Teruhisa Ohno 《Journal of molecular catalysis. A, Chemical》2006,260(1-2):247-254
Nanosized pure TiO2 particles with high crystallinity and large surface area were prepared by hydrolysis of tetrabutyl titanate in water/Triton X-100/isooctane reverse micelle solutions as reaction media followed by hydrothermal treatment to improve crystallinity. The prepared TiO2 nanoparticles were characterized by XRD, BET, TGA, FT-IR and TEM. The size of ultrafine particles was controlled by changing the water content of the reverse micelle solution. The TiO2 particles showed monodispersity, large surface area and high degrees of crystallinity and thermostability. The photocatalytic activity of the TiO2 particles was evaluated by decomposition of toluene in the gas phase. The activity of the TiO2 nanoparticles was higher than that of commercially available anatase fine particles, such as ST-01, which is one of the most active photocatalysts for degradation of organic compounds in the gas phase. 相似文献
234.
The first experimental study on CdS epitaxial thin-film lasers with ZnS substrates is reported. For the first time single crystal layers of CdS have been grown on the (111) faces of ZnS substrate by the hydrogen transport method. Laser emission at 491.8 nm has been observed from these layers cooled near liquid-nitrogen temperature. Optical pumping is performed by the second harmonic of a Q-switched Nd: YAG laser operated at 473 nm, the energy of which exceeds slightly the band-gap energy of the cooled epitaxial CdS layer. The measured optical gain for these CdS thin-films compared with that for platelet CdS single crystals reveals that the optical confinement inside the epitaxial layer increases the optical gain by a factor of about two. 相似文献
235.
Shun-Ichi Nozakura Shigeichi Ishihara Yoshiaki Inaba Keiji Matsumura Shunsuke Murahashi 《Journal of polymer science. Part A, Polymer chemistry》1973,11(5):1053-1067
Bulky substituents in vinyl trialkylsilyl ethers and vinyl trialkylcarbinyl ethers led to heterotactic polymers (H = 66%). The polymers were converted into poly(vinyl alcohol) (PVA) and further to poly(vinyl acetate), and tacticity was determined as poly(vinyl acetate). Vinyl triisopropylsilyl ether in nonpolar solvents yielded a heterotactic polymer with a higher percentage of isotactic triads than syndiotactic triads (Hetero-I). Vinyl trialkylcarbinyl ethers in polar solvents gave a heterotactic polymer with more syndiotactic triads than isotactic (Hetero-II). Heterotactic PVA was soluble in water and showed characteristics infrared absorptions. Interestingly, Hetero-I PVA showed no iodine color reaction, but Hetero-II showed a much more intense color reaction than a commercial PVA. The mechanism of heterotactic propagation was discussed in terms of the Markóv chain model. 相似文献
236.
Aqueous mixtures of anionic surfactants with cationically substituted quaternary ammonium derivatives of hydroxyethylcellulose,
JR and LR series, were investigated by several techniques. On adding sodium dodecyl sulfate (SDS) to a polyelectrolyte solution,
phase separation with precipitation occurs in a co-operative way, and redissolution of precipitation is observed at the critical
micelle concentration (CMC) of SDS. This is due to admicelle formation on the polyelectrolyte. The phase separation for the
two-headed anionic surfactant systems is also seen, while the concentration where this takes place is near the CMC of the
surfactant. This is remarkable in the case of the triethanolamine cocoyl glutamate (TCG)–JR 400 system, in which TCG has a
CMC over 1 order of magnitude smaller CMC than that of SDS. Surface tension and the dynamic light scattering measurements
show the existence of not only electrostatic interaction between the cationic polyelectrolyte and the two-headed anionic surfactant
but also intraction between the adsorbed polymers. The scaling analysis of the precipitation line of the surfactant with polyelectrolyte
concentration elucidates that one molecule of TCG can neutralize approximately two charges on JR 400.
Received: 9 February 1999 Accepted in revised form: 23 June 1999 相似文献
237.
238.
A new method for narrowing the oscillation spectrum of a broad-band dye laser is reported in this paper. The narrowing is achieved by a vapor prism placed inside the laser cavity, which is based on an anomalous dispersion of the atomic vapor so that the narrowing effect occurs only in the vicinity of the absorption line. Using a sodium vapor prism inside a Rhodamine 6G dye laser cavity, an oscillation linewidth less than 0.01 nm was attained at a sodium temperature of 320°C. 相似文献
239.
240.