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321.
The phosphorylation of a peptide is considered to be one of the most important post-translational modification reactions that can alter protein function in mammalian cells. To separate and purify, we developed a dual temperature- and pH-responsive chromatography based on terpolymer composed of N-isopropylacrylamide, N,N'-dimethylaminopropylacrylamide and butylmethacrylate. The property of the surface of the terpolymer-grafted stationary phase altered from hydrophilic to hydrophobic, and from changed to non-charged by changes in the temperature and the pH, respectively. In addition, it was possible to appear and hide ion-exchange groups on the polymer chain surface by temperature changes. These phenomena resulted from changes in the charge and the hydrophobicity of the pH- and temperature-responsive polymer on the stationary surface by controlling the temperature. In the developed environmental-responsive chromatographic system, the ionizable dimethylamino group of N,N'-dimethylaminopropylacrylamide in terpolymer played a key role for the separation. We applied the developed chromatographic system to the separation of phosphorylated compounds, such as phospho-tyrosine, phosphopeptide and oligonucleotides. At a low column temperature, the electrostatic interaction plays a predominant role for retain anionic phosphorylated compounds, because of the strong interaction between the cationic dimethylamino group in the stationary phase and the anionic phosphoric group in the analyte. On the contrary, the hydrophobic interaction became predominant upon increasing the temperature. The results showed that both the electrostatic and the hydrophobic interactions became controllable with a temperature change during the chromatographic process. Dual pH- and temperature-responsive chromatography would be very useful for biomacromolecules separation and purification. 相似文献
322.
Kanazawa K Taninaka A Huang H Nishimura M Yoshida S Takeuchi O Shigekawa H 《Chemical communications (Cambridge, England)》2011,47(40):11312-11314
The step-by-step analysis of a hierarchical self-assembly revealed the incorporation of nanocavity blocks in a metastable orientation to stabilize the organized array. The confinement of 2D electrons by a quantum corral was verified. Furthermore, manipulation of an isolated C(60) molecule was realized using nanocavities of ~1.3 nm diameter as a template. 相似文献
323.
Kanazawa N Onose Y Arima T Okuyama D Ohoyama K Wakimoto S Kakurai K Ishiwata S Tokura Y 《Physical review letters》2011,106(15):156603
We have observed an unconventional, likely topological, Hall effect over a wide temperature region in the magnetization process of a chiral-lattice helimagnet MnGe. The magnitude of the topological Hall resistivity is nearly temperature-independent below 70 K, which reflects the real-space fictitious magnetic field proportional to a geometric quantity (scalar spin chirality) of the underlying spin texture. From the neutron diffraction study, it is anticipated that a relatively short-period (3-6 nm) noncoplanar spin structure is stabilized from the proper screw state in a magnetic field to produce the largest topological Hall response among the B20-type (FeSi-type) chiral magnets. 相似文献
324.
Sunlight‐Driven Hydrogen Peroxide Production from Water and Molecular Oxygen by Metal‐Free Photocatalysts 下载免费PDF全文
Dr. Yasuhiro Shiraishi Shunsuke Kanazawa Yusuke Kofuji Hirokatsu Sakamoto Dr. Satoshi Ichikawa Dr. Shunsuke Tanaka Prof. Takayuki Hirai 《Angewandte Chemie (International ed. in English)》2014,53(49):13454-13459
Design of green, safe, and sustainable process for the synthesis of hydrogen peroxide (H2O2) is a very important subject. Early reported processes, however, require hydrogen (H2) and palladium‐based catalysts. Herein we propose a photocatalytic process for H2O2 synthesis driven by metal‐free catalysts with earth‐abundant water and molecular oxygen (O2) as resources under sunlight irradiation (λ>400 nm). We use graphitic carbon nitride (g‐C3N4) containing electron‐deficient aromatic diimide units as catalysts. Incorporating the diimide units positively shifts the valence‐band potential of the catalysts, while maintaining sufficient conduction‐band potential for O2 reduction. Visible light irradiation of the catalysts in pure water with O2 successfully produces H2O2 by oxidation of water by the photoformed valence‐band holes and selective two‐electron reduction of O2 by the conduction band electrons. 相似文献
325.
D'Amour JN Stålgren JJ Kanazawa KK Frank CW Rodahl M Johannsmann D 《Physical review letters》2006,96(5):058301
The strength of the contacts between small glass spheres and the surface of a quartz crystal resonator has been probed based on the increase of resonance frequency induced upon sphere contact. The acoustic interaction between the sphere and the plate is modeled as a low-frequency coupled resonance; the dependence of the resonant parameters on overtone order lends support to this model. After exposing the sample to humid air and drying it again, the contact strength increases at least tenfold due to capillary forces--we observe a hysteretic form of the sand-castle effect. Repeated wet-dry cycles reveal logarithmic capillary aging with time. The experiments suggest that the drying of the liquid bridges leads to a contraction of small voids in the contact zone, subsequently increasing cohesion. 相似文献
326.
Tang CJ Babjak M Anderson RJ Greene AE Kanazawa A 《Organic & biomolecular chemistry》2006,4(20):3757-3759
Enantiopure 20(S)-camptothecin has been prepared from a known hydroxypyridone through a novel approach that involves a Claisen rearrangement, an asymmetric nucleophilic ethylation, a Heck coupling and a Friedl?nder condensation as the key transformations. 相似文献
327.
We present a leading order (LO) estimate for the longitidinal-transverse spin asymmetry (A
) in the nucleon-nucleon polarized Drell-Yan process at RHIC and
energies in comparison with A
and A
. A
receives contribution from g1, the transversity distribution h1, and the twist-3 distributions g
and h
. For the twist-3 contribution we use the bag model prediction evolved to a high energy scale by the large-Nc evolution equation. We found that A
(normalized by the asymmetry in the parton level) is much smaller than the corresponding A
. Twist-3 contribution given by the bag model turned out to be negligible. 相似文献
328.
Matsuta K. Onishi T. Fukuda M. Minamisono T. Akai H. Sasaki M. Yamaguchi T. Miyake T. Sato K. Minamisono K. Ohsumi F. Muramoto Y. Oui S. Ha C. Tanaka K. Kidera K. Morishita A. Kitagawa A. Torikoshi M. Kanazawa M. Nishio T. Koda S. Ohtsubo T. Fukuda S. Nojiri Y. Momota S. Ozawa A. Yoshida K. Suzuki T. Kobayashi T. Tanihata I. Hanna S.S. Alonso J.R. Krebs G.F. Symons T.J.M. 《Hyperfine Interactions》1999,120(1-8):673-677
The β-NMR spectra of 21F, 23Mg, 27Si and 39Ca which were produced in heavy ion collisions and implanted in various crystals have been observed. The magnetic moments
of 21F and 27Si were determined to be |μ(21F)| = 3.9194 ± 0.0012 μN and |μ(27Si)| = 0.8653 ± 0.0003 μN, respectively. The electric quadrupole coupling constants were determined for the first time to be |eqQ(21F in MgF2)/h|= 9.94 ± 0.09 MHz, |eqQ(23Mg in MgF2)/h|= 1.96 ± 0.06 MHz, |eqQ(27Si in Al2O3)/h|= 1.90 ± 0.12 MHz, |eqQ(39Ca in CaCO3)/h|= 0.60 ± 0.04 MHz. From the present eqQ/h, the Q moments were deduced as |Q(21F)|= 110 ± 22 mb, |Q(23Mg)|= 114 ± 3 mb, |Q(27Si)|= 60 ± 13 mb and |Q(39Ca)|= 36± 7 mb. The present data were compared with the theoretical values obtained by the OXBASH shell model code.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
329.
Hitoshi Kanazawa Jun Magoshi 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(3):o159-o161
The structure of the title compound, benzyl (1,2,3,4‐tetrahydro‐2,5‐dioxo‐1,3‐oxazol‐4‐yl)acetate, C12H11NO5, has been determined in an attempt to explain the polymerization observed in the solid state. The molecules are linked by intermolecular hydrogen bonds between the imino group of the five‐membered ring and an adjacent carbonyl O atom, along the c axis. Intramolecular hydrogen bonds are also formed, between the imino group and the carbonyl O atom of the ester group. The five‐membered rings are arranged in a layer, sandwiched by layers incorporating the benzyl groups. This structure is thought to be preferable for the polymerization of the compound in the solid state, because the five‐membered rings can react with each other in the layer. 相似文献