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排序方式: 共有433条查询结果,搜索用时 15 毫秒
81.
82.
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
83.
Naomi Tanikawa Hidetoshi Akimoto Katsunori Ogoh Wu Chun Yoshihiro Ohmiya 《Photochemistry and photobiology》2004,80(1):31-35
To collect information on gene expression during the dark period in the luminous dinoflagellate Lingulodinium polyedrum, normalized complementary DNA (cDNA) libraries were constructed from cells collected during the first hour of night phase in a 12:12 h light‐dark cycle. A total of 4324 5′‐end sequence tags were isolated. The sequences were grouped into 2111 independent expressed sequence tags (EST) from which 433 groups were established by similarity searches of the public nonredundant protein database. Homology analysis of the total sequences indicated that the luminous dinoflagellate is more similar to land plants and animals (vertebrates and invertebrates) than to prokaryotes or algae. We also isolated three bioluminescence‐related (luciferase and two luciferinbinding proteins [LBP]) and 37 photosynthesis‐related genes. Interestingly, two kinds of LBP genes occur in multiple copies in the genome, in contrast to the single luciferase gene. These cDNA clones and EST sequence data should provide a powerful resource for future genome‐wide functional analyses for uncharacterized genes. 相似文献
84.
Naomi Nishioka Koji Takagi Takatoshi Kinoshita Hideo Kunisada Yasuo Yuki 《Journal of polymer science. Part A, Polymer chemistry》2004,42(5):1208-1215
Tropone‐fused, various π‐conjugated polymers ( P2 – P5 ) were synthesized by the palladium‐catalyzed coupling reaction of 1,4‐dibromo‐6,8‐dimethyl‐7H‐benzocyclohepten‐7‐one with aromatic divinyl, diboronic acid, and diethynyl compounds. The molecular orbital calculation of the model compounds was performed to discuss effective conjugation length of the repeating unit of the polymers. The absorption spectra of phenylenevinylene‐type polymers shifted to longer wavelengths than the model compounds by about 60 nm. They exhibited green fluorescence [λmax(em) = 544 and 561 nm]. The absorption spectrum of a phenylene‐type polymer blueshifted by 10 nm; however, that of a phenyleneethynylene‐type polymer redshifted by 83 nm as compared with their model compounds. They showed fluorescence with peak maxima at 457 and 489 nm, respectively. As a result, the absorption spectra of phenylene‐ and phenylenevinylene‐type polymers blueshifted, but that of a phenyleneethynylene‐type polymer redshifted by the annulation of tropone onto a benzene ring in the conjugated polymer. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1208–1215, 2004 相似文献
85.
Hisashi Hayashi Masaki Kawata Atsushi Sato Naomi Kawamura 《Journal of Physics and Chemistry of Solids》2005,66(12):2168-2172
Kβ resonant inelastic X-ray scattering (RIXS) spectra of Mn and Ga compounds are studied to examine different types of selective XANES. RIXS spectra of MnO in Mn Kβ1,3 region and of GaCl2 in Ga Kβ2 region are plotted as contour maps over wide energy ranges in both excitation and emission. Through analyses of RIXS contour maps by the use of the Kramers-Heisenberg equation, spin-selective XANES spectra are deduced for MnO. In the case of a mixed valence compound GaCl2 selective XANES of Ga3+ ion can be obtained by making use of a large difference in transition probabilities. 相似文献
86.
Susumu Ohira Hiroyuki Fujiwara Kiyomi Maeda Masaharu Habara Naomi Sakaedani Megumi Akiyama Atsuhito Kuboki 《Tetrahedron letters》2004,45(8):1639-1641
All diastereomers of pentenocin B, an inhibitor of interleukin-1β converting enzyme produced by Trichoderma hamatum FO-6903, were synthesized in chiral forms starting from l-threonine. Absolute configurations of natural pentenocin B were clarified to be 4S, 5R, and 6R. 相似文献
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Hanna Dodiuk Edward M. Kosower Michael Ottolenghi Naomi Orbach 《Chemical physics letters》1977,49(1):174-176
The triplets generated by laser pulse excitation of N-methyl-2-N-phenylamino-6-naphthalenesulfonate (1M) and its C-protonated form, the N-methyl betaine of 6-sulfonato-3β-tetralenone N-phenylimine (2M) are distinct and apparently do not interconvert at 25°C either in dioxane-water or in glycerol, for which single pulses must be used to avoid conversion of 1M to 2M. Some parallel results are reported for the N-hydroxyethyl derivatives (1HEand2HE). 相似文献