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91.
Dr. Shungo Kobori Prof. Dr. Yohei Yokobayashi 《Angewandte Chemie (International ed. in English)》2016,55(35):10354-10357
Recent discoveries of new classes of self‐cleaving ribozymes in diverse organisms have triggered renewed interest in the chemistry and biology of ribozymes. Functional analysis and engineering of ribozymes often involve performing biochemical assays on multiple ribozyme mutants. However, because each ribozyme mutant must be individually prepared and assayed, the number and variety of mutants that can be studied are severely limited. All of the single and double mutants of a twister ribozyme (a total of 10 296 mutants) were generated and assayed for their self‐cleaving activity by exploiting deep sequencing to count the numbers of cleaved and uncleaved sequences for every mutant. Interestingly, we found that the ribozyme is highly robust against mutations such that 71 % and 30 % of all single and double mutants, respectively, retain detectable activity under the assay conditions. It was also observed that the structural elements that comprise the ribozyme exhibit distinct sensitivity to mutations. 相似文献
92.
Ion‐Free and Ion‐Pairing Assemblies of Anion‐Responsive π‐Electronic Systems Possessing Directly Linked Alkyl Chains
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Dr. Yohei Haketa Daisuke Katayama Shinya Fukunaga Dr. Yuya Bando Dr. Tsuneaki Sakurai Dr. Wakana Matsuda Prof. Shu Seki Prof. Hiromitsu Maeda 《化学:亚洲杂志》2016,11(14):2025-2029
Alkyl‐substituted pyrrole‐based anion‐responsive π‐electronic systems formed supramolecular gels and liquid crystals through effective π–π stacking and van der Waals interactions. The addition of chloride as a planar cation salt afforded ion‐pairing assemblies as soft materials comprising planar receptor‐Cl? complexes and the cation. 相似文献
93.
94.
Six new sesquiterpenoid quinones with an amino acid residue, metachromins L-Q (1-6), have been isolated from an Okinawan marine sponge Spongia sp. The structures and stereochemistry of 1-6 were elucidated on the basis of the spectroscopic data and chemical correlations. Metachromins L (1) and M (2) showed modest cytotoxicity. 相似文献
95.
Reengineering a natural riboswitch by dual genetic selection 总被引:2,自引:0,他引:2
96.
Yohei Tachiya 《Journal of Number Theory》2007,125(1):182-200
We prove the transcendence results for the infinite product , where Ek(x), Fk(x) are polynomials, α is an algebraic number, and r?2 is an integer. As applications, we give necessary and sufficient conditions for transcendence of and , where Fn and Ln are Fibonacci numbers and Lucas numbers respectively, and {ak}k?0 is a sequence of algebraic numbers with log‖ak‖=o(rk). 相似文献
97.
Takahashi Y Yamada M Kubota T Fromont J Kobayashi J 《Chemical & pharmaceutical bulletin》2007,55(12):1731-1733
Three new sesquiterpenoids, metachromins R--T (1--3), have been isolated from an Okinawan marine sponge Spongia sp. The structures and stereochemistry of 1--3 were elucidated on the basis of the spectroscopic data. Metachromins S (2) and T (3) showed modest cytotoxicity. 相似文献
98.
Kataoka T Nagao Y Kidowaki M Araki J Ito K 《Colloids and surfaces. B, Biointerfaces》2007,56(1-2):270-Optics
Liquid–liquid equillibria (LLE) of the tertiary system of hydroxypropylated polyrotaxane (HPPR)–poly(vinyl alcohol) (PVA)–solvent have been investigated by focusing on the internal structures of HPPR–PVA blend gels. The phase diagrams of the HPPR–PVA aqueous systems displayed two liquid phases at a high concentration and molecular weight of PVA. This result was consistent with the prediction of the Flory–Huggins lattice model. On the contrary, the HPPR–PVA–DMSO system exhibited only a single phase. The HPPR–PVA blend gels crosslinked in dimethylsulfoxide (DMSO) were highly transparent over a wide concentration range, while the gels prepared in water were opaque at high polymer concentrations. Spherical domains were observed in the opaque gels by laser scanning confocal microscopy, and the sizes of the domains were significantly dependent on the amount of cross-linking reagent utilized. These results indicated that the transparency of the HPPR–PVA blend gels was strongly affected by the competition between the liquid–liquid two-phase separation and the crosslinking HPPR and PVA polymers during the preparation of the blend gels. 相似文献
99.
The atomic force microscope (AFM) was used to manipulate surface structures of conjugated carbon materials (graphite and C70) in the nanometer scale with real space resolution. Soliton superlattice was directly observed on both graphite and C70 single crystals surface. The tip-induced dynamic structural changes were also investigated. 丁he manipulations of both sp3-like line defects on the lattice of graphite and individual C70 molecules on defect-free surface or at molecular layer edges were suggested. 相似文献
100.
Itaru Sato Yohei Matsueda Kousuke Kadowaki Shigeru Yonekubo Takanori Shibata Kenso Soai 《Helvetica chimica acta》2002,85(10):3383-3387
1,3‐Disubstituted chiral allenes without any heteroatoms act as chiral initiators in the addition of (i‐Pr)2Zn to pyrimidine‐5‐carbaldehyde to afford, in combination with the subsequent asymmetric autocatalysis, chiral pyrimidin‐5‐yl alkanols with up to 98% ee. The absolute configuration of the pyrimidin‐5‐yl alkanol formed depend on that of the chiral allene. 相似文献