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761.
Aoyama H Noguchi T Misawa T Nakamura T Miyachi H Hashimoto Y Kobayashi H 《Chemical & pharmaceutical bulletin》2007,55(6):944-949
We synthesized a series of compounds based on the potent tubulin-polymerization inhibitor 5-hydroxy-2-(2,6-diisopropylphenyl)-1H-isoindole-1,3-dione [5HPP-33 (3)], which is structurally derived from thalidomide (1), and investigated their inhibitory effects on tubulin polymerization. Direct interaction between 5HPP-33 (3) and alpha,beta-tubulin heterodimer protein was demonstrated by means of a surface plasmon resonance study. 相似文献
762.
Yamamoto T Tassel C Kobayashi Y Kawakami T Okada T Yagi T Yoshida H Kamatani T Watanabe Y Kikegawa T Takano M Yoshimura K Kageyama H 《Journal of the American Chemical Society》2011,133(15):6036-6043
The layered compound SrFeO(2) with an FeO(4) square-planar motif exhibits an unprecedented pressure-induced spin state transition (S = 2 to 1), together with an insulator-to-metal (I-M) and an antiferromagnetic-to-ferromagnetic (AFM-FM) transition. In this work, we have studied the pressure effect on the structural, magnetic, and transport properties of the structurally related two-legged spin ladder Sr(3)Fe(2)O(5). When pressure was applied, this material first exhibited a structural transition from Immm to Ammm at P(s) = 30 ± 2 GPa. This transition involves a phase shift of the ladder blocks from (1/2,1/2,1/2) to (0,1/2,1/2), by which a rock-salt type SrO block with a 7-fold coordination around Sr changes into a CsCl-type block with 8-fold coordination, allowing a significant reduction of volume. However, the S = 2 antiferromagnetic state stays the same. Next, a spin state transition from S = 2 to S = 1, along with an AFM-FM transition, was observed at P(c) = 34 ± 2 GPa, similar to that of SrFeO(2). A sign of an I-M transition was also observed at pressure around P(c). These results suggest a generality of the spin state transition in square planar coordinated S = 2 irons of n-legged ladder series Sr(n+1)Fe(n)O(2n+1) (n = 1, 2, 3, ...). It appears that the structural transition independently occurs without respect to other transitions. The necessary conditions for a structural transition of this type and possible candidate materials are discussed. 相似文献
763.
764.
Adsorption structures and interaction of cyclohexane molecules on the clean and hydrogen-preadsorbed Rh(111) surfaces were investigated using scanning tunneling microscopy, spot-profile-analysis low-energy electron diffraction, temperature-programmed desorption, and infrared reflection absorption spectroscopy (IRAS). Various ordered structures of adsorbed cyclohexane were observed as a function of hydrogen and cyclohexane coverages. When the fractional coverage (θ(H)) of preadsorbed hydrogen was below 0.8, four different commensurate or higher-order commensurate superstructures were found as a function of θ(H); whereas more densely packed incommensurate overlayers became dominant at higher θ(H). IRAS measurements showed sharp softened C-H vibrational peaks at 20 K, which originate from the electronic interaction between adsorbed cyclohexane and the Rh surface. The multiple softened C-H stretching peaks in each phase are due to the variation in the adsorption distance from the substrate. At high hydrogen coverages they became attenuated in intensity and eventually diminished at θ(H) = 1. The gradual disappearance of the soft mode correlates well with the structural phase transition from commensurate structures to incommensurate structures with increasing hydrogen coverage. The superstructure of adsorbed cyclohexane is controlled by the delicate balance between adsorbate-adsorbate and adsorbate-substrate interactions which are affected by preadsorbed hydrogen. 相似文献
765.
Ikebe J Umezawa K Kamiya N Sugihara T Yonezawa Y Takano Y Nakamura H Higo J 《Journal of computational chemistry》2011,32(7):1286-1297
Trivial trajectory parallelization of multicanonical molecular dynamics (TTP-McMD) explores the conformational space of a biological system with multiple short runs of McMD starting from various initial structures. This method simply connects (i.e., trivially parallelizes) the short trajectories and generates a long trajectory. First, we theoretically prove that the simple trajectory connection satisfies a detailed balance automatically. Thus, the resultant long trajectory is regarded as a single multicanonical trajectory. Second, we applied TTP-McMD to an alanine decapeptide with an all-atom model in explicit water to compute a free-energy landscape. The theory imposes two requirements on the multiple trajectories. We have demonstrated that TTP-McMD naturally satisfies the requirements. The TTP-McMD produces the free-energy landscape considerably faster than a single-run McMD does. We quantitatively showed that the accuracy of the computed landscape increases with increasing the number of multiple runs. Generally, the free-energy landscape of a large biological system is unknown a priori. The current method is suitable for conformational sampling of such a large system to reduce the waiting time to obtain a canonical ensemble statistically reliable. 相似文献
766.
In this study, non-engineered RNAs were detected in living cells using bioluminescence. Two types of probe were utilized: a peptide inserted RLuc (PI-RLuc) probe and a split-RNA probe. Incorporation of the PI-RLuc and split-RNA probes enabled the direct detection of RNA introduced into living cells. 相似文献
767.
Tanaka K Kanazawa T Ogawa T Suda Y Takashima Y Fukuda T Okada H 《Chemical & pharmaceutical bulletin》2011,59(2):202-207
We have engineered a novel, non-viral, multifunctional gene vector (STR-CH(2)R(4)H(2)C) that contained stearoyl (STR) and a block peptide consisting of Cys (C), His (H), and Arg (R). STR-CH(2)R(4)H(2)C can form a stable nano-complex with plasmid DNA (pDNA) based on electronic interactions and disulfide cross linkages. In this study, we evaluated the efficacy of STR-CH(2)R(4)H(2)C as a gene vector. We first determined the optimal weight ratio for STR-CH(2)R(4)H(2)C/pDNA complexes. The complexes with a weight ratio of 50 showed the highest transfection efficacy. We also examined the transfection efficacy of STR-CH(2)R(4)H(2)C/pDNA complexes with or without serum and compared STR-CH(2)R(4)H(2)C/pDNA transfection efficacy with that of Lipofectamine. Even in the presence of serum, STR-CH(2)R(4)H(2)C showed higher transfection efficacy than did Lipofectamine. In addition, we determined the mechanism of transfection of the STR-CH(2)R(4)H(2)C/pDNA complexes using various cellular uptake inhibitors and evaluated its endosomal escape ability using chloroquine. Macropinocytosis was main cellular uptake pathway of STR-CH(2)R(4)H(2)C/pDNA complexes. Our results suggested that STR-CH(2)R(4)H(2)C is a promising gene delivery system. 相似文献
768.
Takanori Tsutaoka Koji ShimomuraAkira Tanaka 《Journal of magnetism and magnetic materials》2011,323(23):3147-3150
Magnetovolume effect in Nd7Rh3 single crystal has been studied by measuring the magnetostriction as a function of external magnetic field at 4.2 K. An irreversible magnetovolume effect having a negative remanent volume magnetostriction was observed when the external magnetic field was applied along the b-axis. The irreversible magnetostrictive effect takes place in the longitudinal magnetostriction along the b-axis. The remanent magnetostriction along the b-axis relaxes after removing external magnetic field for several hours and equilibrium state is stabilized. 相似文献
769.
Koga T Jiang N Gin P Endoh MK Narayanan S Lurio LB Sinha SK 《Physical review letters》2011,107(22):225901
We report the origin of the effect of nanoscale confinement on the local viscosity of entangled polystyrene (PS) films at temperatures far above the glass transition temperature. By using marker x-ray photon correlation spectroscopy with gold nanoparticles embedded in the PS films prepared on solid substrates, we have determined the local viscosity as a function of the distance from the polymer-substrate interface. The results show the impact of a very thin adsorbed layer (~7 nm in thickness) even without specific interactions of the polymer with the substrate, overcoming the effect of a surface mobile layer at the air-polymer interface and thereby resulting in a significant increase in the local viscosity as approaching the substrate interface. 相似文献
770.
Teruaki Toyota Tadashi Hanafusa Takashi Oda Iwane Koumura Takanori Sasaki Eiji Matsuura Hiromi Kumon Tsuneo Yano Toshiro Ono 《Journal of Radioanalytical and Nuclear Chemistry》2013,298(1):295-300
Ion exchange is a simple and efficient method for separating no-carrier-added 64Cu from an irradiated Ni target. We developed a semi-automated two-round 64Cu separation system equipped with a strong-base anion exchange resin column. We first verified the efficiency of the system using a non-radioactive substitute consisting of 25 mg of Ni and 127 ng of Cu, and confirmed that Cu was completely eluted at the second round of the separation step. After the bombardment, separation of 64Cu from the Ni target was achieved with high radiochemical purity. 64Cu produced and separated in this study had an extremely low level of Ni impurity. It could be used for labeling monoclonal antibodies for antibody positron emission tomography imaging and synthesizing radiopharmaceuticals. 相似文献