Showing papers by "Aoyama Gakuin University published in 1981"

The Use of Diethyl Azodicarboxylate and Triphenylphosphine in Synthesis and Transformation of Natural Products

Abstract: The reagent formed by combining diethyl azodicarboxylate (DEAD) and triphenylphosphine (TPP) could be utilized in the intermolecular dehydration between an alcohol and various acidic components such as carboxylic acids, phosphoric diesters, imides, and active methylene compounds. By the use of DEAD and TPP, diols and hydroxy acids gave cyclic ethers and lactones, respectively. The reaction of nucleosides with DEAD and TPP afforded triphenylphosphoranylnucleosides. Alcohols reacted with 2,6-di-t-butyl-4-nitrophenol in the presence of DEAD and TPP to give aci-nitroesters which converted into the corresponding carbonyl compounds.

The Relationship Between Conflict Resolution Approaches and Trust—A Cross Cultural Study

Abstract: This study investigated whether the manner in which conflicts are resolved in Japanese-American joint ventures in Japan influences the level of future mutual trust. Japanese managers perceived a hi...

The Price Effects of Spatial Competition

Abstract: A recent paper by Capozza and Van Order (CVO) (1977) proposed a generalization of the Greenhut-Hwang-Ohta (GHO) (1975) analysis of pricing under three alternative types of spatial competition. The GHO analysis was based on a short-run model in which the locations of firms are assumed to be fixed. CVO accordingly proposed relaxation of this rigid assumption to examine if the GHO results also apply to the long-run zero-profit industry equilibrium. They confirmed the GHO results, which, however, they also contended, require certain particular modifications as well in the light of their own models. The CVO contribution lies in their simple model analysis of long-run industry equilibrium conditions-a generalization of the GHO analysis. However, they failed to recognize that the GHO analysis is based on another restrictive assumption regarding the form of the demand function. Moreover, they assumed even more restrictive demand conditions and misled themselves to a conclusion that L6schian competition never results in a lower price than spatial monopoly. Their conclusion is invalid since Loschian competition can be shown to result in a lower (not higher) mill price if only the demand function is assumed to be sufficiently convex to the origin (Ohta (1980)). This calls for a more general examination of conditions under which the firm's f.o.b. mill price may rise or fall due to spatial entry of rival firms. The present paper presents selected results of such examination. Section 2 briefly reviews the theory of spatial monopoly. Initially some fundamental assumptions are set forth. This is followed by derivation of the market demand function for the spatial monopolist. The market demand in turn is shown to be more or less elastic than the assumed basic demand function depending on the curvature of the latter curve. We also comment on the so-called "paradox of spatial monopoly", which we claim is a misnomer. The analytical framework of Section 2 is employed in Section 3 as we generalize previous analyses and present a concise cataloguing of comparative static results of spatial competition.1 Again the basic demand characteristics, in combination with alternative types of spatial competition, are shown to play an important role in yielding the distinct elasticity results, and for that matter competitive equilibrium prices. In the process a counter-example to CVO's aforementioned argument on L6schian pricing is presented. Also discussed is the conceptual distinction between perceived and realized elasticities of demand under spatial competition, which CVO also failed to recognize. As a result, they erred in speculating that equilibrium mill prices would be the same under alternative types of spatial competition, given the size of the market area. We will show that they in fact are not. Section 4 concludes the paper by summarizing the basic results of our analysis.

Subcellular distribution and characterization of porcine kidney catalase.

Abstract: Subcellular distribution of catalase for porcine kidney was analyzed by differential centrifugation of kidney homogenate. The specific activity of catalase was the highest in light mitochondrial fraction, followed by mitochondrial, cytosolic, nuclear, and microsomal fractions. However, about a half of the total activity was found in supernatant (cytosol) fraction and the other half was mainly associated with both mitochondrial and light mitochondrial fractions. Osmotic shock using hypotonic solution, 50 mm sodium phosphate buffer (pH 7.0) was found to be most effective for solubilization of particulate-bound catalase. Both particulate and cytosol catalases from porcine kidney were purified by ammonium sulfate fractionation followed by DEAE-cellulose, CM-cellulose, and Sephadex G-100 column chromatographies. The purified enzymes showed two distinct bands, one major and the other minor, on disc gel electrophoresis. Both particulate and cytosol enzymes showed identical molecular weights estimated from disc gel electrophoresis; that of the major component was 219,000 corresponding to native molecule and that of the minor one 421,000. A similar value, 210,000, was also obtained for the major component by gel filtration on a Bio Gel A-1.5 m column. It was inferred that the minor component was formed by dimerization of native molecule caused by formation of disulfide cross-links due to oxidation of SH groups in protein moiety. The particulate and cytosol catalases showed essentially identical molecular characteristics, although a slight difference was detected in stability in guanidine-HCl solution. The effect of NaCl on enzyme activity and optical properties of catalase were also measured.

A shell-model study onM1 andE2 properties of Zn, Ga, and Ge

Abstract: Electromagnetic properties of Zn, Ga, and Ge are studied by using the nuclear shell model. Empirically determinedM1 operators are found to be very successful to explainM1 transitions, moments, and mixing ratios. ManyE2 properties are also understood by the present shell-model calculations with effective charges.

Bromine NMR Study of Cupric Compounds (C n H 2n+1 NH 3 ) 2 CuBr 4 (n{=}1, 2)

Abstract: The spin structure of (C n H 2 n +1 NH 3 ) 2 CuBr 4 ( n =1, 2) is studied by Br NMR at 1.7 K. In (C 2 H 5 NH 3 ) 2 CuBr 4 , the magnetic space group is P b ' c ' a type and the moment direction inclines at an angle of 49.5° with the c -axis. A weak ferromagnetic moment appears along to the c -axis. The anisotropic exchange field is estimated to be 2.5 kOe. The inter-layer exchange field and the out-of-layer anisotropy field are much smaller than previously reported values. The parameters of Br nuclear spin Hamiltonian are also obtained. In (CH 3 NH 3 ) 2 CuBr 4 , the moment direction inclines at 27° with the c -axis. It is difficult to interpret the NMR results by the two-sublattice model. A model of the four-sublattice antiferromagnet is developped.

On the acid denaturation of porcine erythrocyte catalase in relation to its subunit structure.

Abstract: Porcine erythrocyte catalase [EC 1.11.1.6] (molecular weight, ca. 250,000) was found to dissociate partially between pH 3.5 and 3.0 and completely below pH 3.0 into two presumably identical 1/2-sized subunits (molecular weight, 112,000) as estimated by ultracentrifugal analyses. This dissociation was accompanied by a marked change in hydrodynamic properties; the sedimentation coefficient decreased from about 11S to 4S. This acid denaturation also resulted in complete loss of enzyme activity and disappearance of absorption bands characteristic of heme protein, in particular, a shift of the Soret band from 405 nm to a small and broad band at 375 nm. The change in enzyme activity correlated well with that of the Soret band, depending on the denaturation time and pH used. Reversible recovery of enzyme activity was not detected below pH 3.1 after 2 h denaturation. The pH dependence of alpha-helical content estimated from the CD intensity at 222 nm also correlated well with that of enzyme activity. The rate constants of initial reaction of acid denaturation at several pHs were determined by following the changes in the Soret band with time, since the changes showed an isosbestic point at 384 nm. The results revealed that the first-order rate constant at pH 3.0 was 45 times larger than that at pH 3.4, indicating that the rate of acid denaturation increased rapidly within a narrow acidic pH range. The temperature dependence of the denaturation rate was also measured and the activation energy for the acid denaturation was found to be 76.3 kcal/mol from an Arrhenius plot.

Magnetization distribution of V 51 studied by elastic electron scattering through 180

Abstract: Scattering from the $M3$, $M5$, and $M7$ moments of the ground state of $^{51}\mathrm{V}$ has been observed by a 180\ifmmode^\circ\else\textdegree\fi{} scattering experiment of electrons. The observed $M3$ and $M5$ form factors are much smaller than those expected from the single-particle model. The features are reasonably reproduced by the calculation which takes into account the effect of the configuration mixing including the polarization of the $^{48}\mathrm{Ca}$ core.NUCLEAR REACTIONS $^{51}\mathrm{V}(e,e)$ $E=80.84\ensuremath{-}229$ MeV, $\ensuremath{\theta}=180\ifmmode^\circ\else\textdegree\fi{}$, measured $\ensuremath{\sigma}(E,180\ifmmode^\circ\else\textdegree\fi{})$; deduced magnetic moment form factor.

Magnetic Impurity States in Semiconductors

Abstract: On the basis of a simple model we discuss how impurity atoms can be paramagnetic in semiconductors. The model is a system of two interacting electrons in the conduction band of a semiconductor containing a single donor-type impurity. The band structure is assumed to be such that the corresponding density of states curve has a semi-elliptic form. This band structure is an approximation to that of a real three-dimensional crystal. The problem is formulated in terms of one-electron Green's functions and is solved exactly. The results are qualitatively similar to those obtained by Mattis and Lieb, who exactly solved the same problem in the one-dimensional case. The present solution will be applicable to some two-electron problems associated with deep impurity states in semiconductors.

Heating and quenching of metastable superconducting compounds with a plasma jet

Abstract: Superconducting compounds, such as cubic α-MoC1−x, cubic β-WC1−x, hexagonal MoB2, and cubic δ-TaN, which are metastable at room temperature, have been formed by heating and quenching of their respective equilibrium phases, such as hexagonal η-MoC1−x, hexagonal WC, rhombohedral Mo2B5, and hexagonal e-TaN in a plasma jet. From calculations based on a simple model, the quenching rate of particles has been estimated to be 105 deg s−1.

Neutron scattering study of (CH3NH3)2Cu(Cl0.1Br0.9)4

Abstract: Neutron scattering experiment was carried out to study the magnetic structure of (CH3NH3)2Cu(Cl0.1Br0.9)4. A new magnetic structure model different from those of (CH3NH3)2CuBr4 was proposed. The structural phase change observed at rather higher temperature was briefly discussed.

Alkali metal and alkali metal hydroxide intercalates of the layered transition metal disulfides

Abstract: The intercalation reaction of some layered transition metal disulfides with alkali metals, alkali metal hydroxides, and tetraalkylammonium hydroxides were investigated. The alkali metal intercalates were prepared in the respective metal-hexamethylphosphoric triamide solutions in vacuo, and the hydroxide intercalates in aqueous hydroxide solutions. According to the intercalation reaction, the c-lattice parameter was increased, and the increase indicated the expansion of the interlayer distance. In the case of alkali metal intercalates, the expansion of the interlayer distance increased continuously, corresponding to the atomic radius of the alkali metal. On the other hand, the hydroxide intercalates showed discrete expansion corresponding to the effective ionic radius of the intercalated cation. All intercalates of TaS2 and NbS2 were superconductors. The expansion of the interlayer distance tended to increase the superconducting transition temperature in the intercalates of TaS2 and vice versa in those of NbS2.

Nonvolatile memory effects of chalcogenide amorphous semiconductor doped with AG

Abstract: With Ag-photodoped amorphous As2S3 specimens that have nonvolatile memory effect, the electric conduction, temperature and frequency characteristics and thermoelectromotive force are investigated. The fabrication yield of this specimen is almost 100%. This device has a switching function, and the off-state has a semiconductor type electric conduction with energy gap of 2 eV. The on-state has metallic conduction and its temperature coefficient is almost the same as that of Ag, 4.0 × 10−3/°C. With a lateral-type specimen (Au-Ag electrodes), Ag dendrites are observed under a microscope. The dendrites bridge the two electrodes, resulting in memory action. The bridging of an Ag dendrite played the same role as a crystalline-amorphous phase change in ordinary semiconductor memory operation.