Showing papers by "Masaki Azuma published in 1998"
TL;DR: 4PU-Sepharose 4B, an affinity gel liganded with 4PU, determined partial amino acid sequences of CSBP and isolated its cDNA by reverse-transcription (RT) PCR revealed that CSBP is a novel member of a major pollen allergen/pathogenesis-related protein family.
Abstract: Synthetic urea derivatives such as N-phenyl-N'-(4-pyridyl)urea (4PU) and N-(2-chloro-4-pyridyl)-N'-phenylurea (4PU30) have strong cytokinin activities. Using tritiated 4PU30 as a probe, we previously established the presence of a cytokinin-specific binding protein (CSBP) of high affinity (Ka for 4PU30 = 4x10(10) M(-1)) in the soluble fraction of etiolated mung bean seedlings [Nagata, R., Kawachi, E., Hashimoto, Y. & Shudo, K. (1993) Biochem. Biophys. Res. Commun. 191, 543-549]. In this report, we purified CSBP by the use of 4PU-Sepharose 4B, an affinity gel liganded with 4PU. We determined partial amino acid sequences of CSBP and isolated its cDNA by reverse-transcription (RT) PCR. The cDNA encoded a protein with a calculated molecular mass of 17 kDa. A data base homology search revealed that CSBP is a novel member of a major pollen allergen/pathogenesis-related protein family. Recombinant CSBP was expressed in Escherichia coli and was confirmed to bind specifically to cytokinins.
94 citations
TL;DR: In this paper, the magnetic properties of double perovskite structures and their crystal structures and magnetic properties were investigated at high pressures of 6-8 GPa, and the magnetization data showed an anomalous transition at 110 K.
Abstract: Ln{sub 2}CuSnO{sub 6} (Ln = Pr, Nd, and Sm) and La{sub 2}CuZrO{sub 6} have been stabilized in the same layered double perovskite structure as La{sub 2}CuSnO{sub 6} at high pressures of 6--8 GPa. Their crystal structures and magnetic properties were investigated. Replacement of La{sup 3+} by smaller lanthanide ions and Sn{sup 4+} by larger Zr{sup 4} increased the buckling of the Cu-O-Cu bonds in the CuO{sub 2} layers. In Nd{sub 2}CuSnO{sub 6}, both the Cu and Nd sublattice were found to exhibit weak ferromagnetism owing to spin canting. The magnetization data showed an anomalous transition at 110 K.
61 citations
TL;DR: In this article, an inelastic neutron scattering study was performed on a Zn-substituted spin-1/2 Heisenberg 2-leg ladder compound to investigate nonmagnetic impurity effects on the quantum spin system with a large spin gap of approximately ∼400 K.
Abstract: An inelastic neutron scattering study was performed on a Zn-substituted spin-1/2 Heisenberg 2-leg ladder compound Sr(Cu 1- x Zn x ) 2 O 3 ( x ≤0.04) to investigate nonmagnetic impurity effects on the quantum spin system with a large spin gap of approximately ∼400 K. The magnitude of the spin gap was found to be independent of Zn concentration, 33 meV, while the integrated magnetic scattering, which corresponds to the singlet-triplet excitation, decreased monotonically with increasing x . On account of the total-sum rule, this result supports the existence of a finite in-gap density of states at E = 0, which was suggested from the T -linear magnetic specific heat.
31 citations
TL;DR: Vander Griend et al. as mentioned in this paper described the HP synthesis of a new copper-rich-layered perovskite, LaVergne et al., which can facilitate the synthesis of metastablesuperconductors.
Abstract: Douglas A. Vander Griend, Sophie Boudin, andKenneth R. Poeppelmeier*Department of Chemistry and the Science and TechnologyCenter for SuperconductiVityNorthwestern UniVersity, 2145 Sheridan RoadEVanston, Illinois 60208-3113Masaki Azuma, Hiroki Toganoh, and Mikio TakanoInstitute for Chemical Research, Kyoto UniVersityUji, Kyoto-Fu 611, JapanReceiVed June 29, 1998High pressure (HP) can facilitate the synthesis of metastablesuperconductors because it stabilizes the perovskite structure. Inthis paper, we describe the HP synthesis of a new copper-richlayered perovskite, La
13 citations
TL;DR: In this article, nonmagnetic impurity effects on a two-leg quantum spin ladder with a large spin gap of about 400 K were investigated, and only a few % of impurity was found to drive the host gapless and antiferromagnetically ordered at a composition-dependent temperature below 10 K.
2 citations
TL;DR: In this paper, the NMR lines for the Zn-doped samples (0.25%) showed drastic broadening at low temperatures below 100 K, while not for the pure samples.