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191.
Ishizaka K Arima T Murakami Y Kajimoto R Yoshizawa H Nagaosa N Tokura Y 《Physical review letters》2004,92(19):196404
The temperature (T) dependence of the charge-stripe order in La2-xSrxNiO4 has been investigated in the vicinity of x approximately 1/3 by synchrotron radiation x-ray diffraction measurements. With decreasing T, a prominent commensurate-incommensurate (C-IC) crossover is observed in the x<1/3 region, while for the x>1/3 region the IC order is dominant over the whole T range. Such a C-IC crossover is interpreted as the entropy-driven self-doping of the charge stripes, and its x dependence indicates the clear electron-hole asymmetry with the x=1/3 compound as the Mott insulator. 相似文献
192.
Yoh Sonoda Fumitoshi Hirayama Hidetoshi Arima Kaneto Uekama 《Journal of inclusion phenomena and macrocyclic chemistry》2004,50(1-2):73-77
The amorphous complex of 2-hydroxypropyl--cyclodextrin (HP--CyD) with an oral hypoglycemic agent, chlorpropamide (CPM), in a molar ratio of 1:1 was prepared by the spray-drying method. The effects of storage (temperature and humidity) and moulding pressure on the polymorphic transition of CPM in HP--CyD matrix were investigated, in comparison with those of the CPM polymorphs, Form A (stable form) and Form C (metastable form). The formation of an amorphous complex of CPM with HP--CyD was confirmed by powder X-ray diffractometry and differential scanning calorimetry. During storage at various temperature and humidity conditions, the metastable Form C of CPM converted to the stable Form A, where the conversion proceeded according to the Jander equation with an activation energy of 51 kJ/mol (25–60–°C) and a reaction-order of 1.55 with respect to water content (relative humidity (RH) 20–75%). No polymorphic transition of Form A crystals was observed under the experimental conditions. In the case of the amorphous HP--CyD complex, Form C crystals were slowly produced, but the further conversion of the resulting Form C to Form A was markedly suppressed in HP--CyD matrix. Upon compression (2000kg/cm2), Forms A and C were converted to amorphous CPM in a major portion and Forms C and A, respectively, in a minor portion. The polymorphic transition behavior was clearly reflected in the dissolution rate of CPM, i.e., (1) the dissolution rate was in the order of HP--CyD complex (Form C) Form A, and (2) the dissolution rate of Forms A and C after the compression increased because of the conversion to amorphous state, while the complex maintained the fast dissolving property even after the compression. The results indicated that HP--CyD is useful not only for converting crystalline CPM to an amorphous substance, but also for maintaining the metastable form with fast dissolution rate, Form C, over a long period. 相似文献
193.
Ogawa Y Yamada H Ogasawara T Arima T Okamoto H Kawasaki M Tokura Y 《Physical review letters》2003,90(21):217403
Simultaneously broken time-reversal and spatial-inversion symmetries can be realized in the epitaxially grown oxide "tricolor" superlattices composed of three sequential kinds of perovskite layers including a ferromagnetic one (manganese oxide). As a generic feature of such a system, the magnetic-field-induced second-harmonic generation and the resultant Kerr rotation of second-harmonic light were demonstrated. The signal intensity probes the interface magnetization of the superlattice, where temperature variation is shown to be distinct from the bulk feature. 相似文献
194.
We study the transition from the vibrational, SU(5), to the rotational, SU(3), limit of the interacting boson model. We show how this model can be used to calculate energies, electromagnetic transitions, multipole moments, nuclear radii, and two-nucleon transfer intensities in transitional nuclei. 相似文献
195.
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
196.
Extracellular Production and Characterization of <Emphasis Type="BoldItalic">Streptomyces</Emphasis> X-prolyl Dipeptidyl Aminopeptidase 总被引:1,自引:0,他引:1
Hatanaka T Yamasato A Arima J Usuki H Yamamoto Y Kumagai Y 《Applied biochemistry and biotechnology》2011,164(4):475-486
X-prolyl dipeptidyl aminopeptidases (X-PDAPs) are useful in various food industries. In this study, we performed sequence-based
screening to obtain a stable X-PDAP enzyme from thermophilic Streptomyces strains. We found three genes that encoded X-PDAP from Streptomyces thermoluteus subsp. fuscus NBRC 14270 (14270 X-PDAP), Streptomyces thermocyaneoviolaceus NBRC 14271 (14271 X-PDAP), and Streptomyces thermocoerulescens NBRC 14273, which were subsequently cloned and sequenced. The deduced amino acid sequences of these genes showed high similarity,
with ~80% identity with each other. The isolated X-PDAPs and an X-PDAP from Streptomyces coelicolor were expressed in Streptomyces lividans using a hyperexpression vector: pTONA5a. Among these genes, only 14270 and 14271 X-PDAPs caused overexpression and extracellular production without artificial signal
peptides. We also characterized the biochemical properties of purified 14271 X-PDAP. In addition, we found that, in peptide
synthesis via an aminolysis reaction, this enzyme recognized d-amino acid derivatives as acyl acceptors, similar to l-amino acid derivatives. 相似文献
197.
Versatile and gigantic magnetoelectric (ME) phenomena have been found for a single crystal of DyFeO3. Below the antiferromagnetic ordering temperature of Dy moments, a linear-ME tensor component as large as alphazz approximately 2.4 x 10(-2) esu is observed. It is also revealed that application of magnetic field along the c axis induces a multiferroic (weakly ferromagnetic and ferroelectric) phase with magnetization [> or =0.5 microB/formula unit (f.u.)] and electric polarization (> or =0.2 microC/cm2) both along the c axis. Exchange striction working between adjacent Fe3+ and Dy3+ layers with the respective layered antiferromagnetic components is proposed as the origin of the ferroelectric polarization in the multiferroic phase. 相似文献
198.
199.
Kuga Arima Satoko Akiyama Kazuo Shin-ya Kenichi Matsuda Toshiyuki Wakimoto 《Angewandte Chemie (International ed. in English)》2023,62(29):e202305155
Heterocycles with nitrogen-nitrogen (N−N) bonds are privileged building blocks of synthetic drugs. They are also found in natural products, although the biosynthetic logic behind them is poorly understood. Actinopyridazinones produced by Streptomyces sp. MSD090630SC-05 possess unique dihydropyridazinone rings that have been studied as core nuclei in several approved synthetic therapeutics. Herein, we performed gene knockouts and in vitro biochemical experiments to elucidate the major steps in actinopyridazinone biosynthesis, including the unprecedented carrier protein mediated machinery for dihydropyridazinone formation. 相似文献