Acoustic intensity measurement in a narrow duct by a two-sensor method

The use of two pressure sensors [Fusco et al., J. Acoust. Soc. Am. 91, 2229 (1992)] makes it possible to determine the acoustic intensity of a gas column in a duct, but the application of this method was limited to wide ducts. In this letter, the formulation of the method is modified to include narrow ducts where the duct radius is as small as the viscous boundary layer thickness of the gas. The validity of this method is shown by comparison with the direct measurements of the pressure and velocity.     

Oxidative degradation of carbon blacks with nitric acid: II. Formation of water-soluble polynuclear aromatic compounds

Furnace black and acetylene black were oxidized with concentrated nitric acid at 100 °C for prolonged periods. The oxidized carbon black was dissolved/dispersed into alkaline solution and was size-fractionated into six fractions by ultrafiltration. The yields of the fractions revealed that oxidized furnace black contains oxygenated polynuclear aromatic compounds with a variety of molecular sizes, but oxidized acetylene black consists of only a great quantity of the largest size fraction, probably carbon black particles, and a scarce amount of the smallest size fraction. With oxidized furnace black, elemental compositions of all fractions except the largest molecular-size fraction were independent of the period of oxidation, suggesting that each fraction possesses a similar molecular structure. Noncarbon constituents such as oxygen and hydrogen increased with decreasing molecular size. The mean molecular weights of fractions were estimated to be in a range from ca. 400 to 1200 and more on the basis of elemental and functional group analyses. ¹³C-NMR and IR analysis showed that the molecules of fractions comprise phenolic, carboxylic, nitro, perhaps quinonic carbonyl groups, and aromatic carbons, but no aliphatic carbons. Ultraviolet and visible spectra of fractions denoted that absorption at higher wavelengths increased with increasing the molecular weights, indicating extension in the conjugated aromatic ring system. On the basis of the experimental results molecular structure models for the fractions were proposed.     

High-pressure synthesis of novel compounds in an Mg–Ni system

High-pressure works are attractive techniques to obtain new compounds, such as alkali or alkaline earth metal-based systems. The atomic radius of Mg under GPa pressure is considerably smaller compared with transition metals; as such, it may be preferable to synthesize novel intermetallic compounds and hydrides by using high-pressure techniques. In this study, novel compounds were synthesized in an Mg–Ni system by a high-pressure technique using a cubic-anvil-type apparatus.A novel Mg₆Ni intermetallic compound was obtained by exposing a mixture of Mg and Ni to 6 GPa at 900 °C for 2 h. The crystal structure of the compound is a tetragonal F-43m structure with a lattice parameter of a=1.9987(1) nm. This compound decomposed to Mg and Mg₂Ni phases at 278 °C with exothermic reaction.As is well known, MgNi₂ does not form hydrides under conventional hydrogenation conditions, hence we investigated the reactivity of MgNi₂ with highly pressurized hydrogen. It was found that the MgNi₂ was able to form MgNi₂H_3.2 by treatment at 700 °C for 2 h under 5 GPa with a hydrogen source, leading to a hydrogen capacity of 2.23 mass%. This novel hydride was found to be a tetragonal MoSi₂-type structure (I4/mmm) with lattice parameters of a=0.327(3) nm and c=0.878(9) nm. The dehydrogenation of this hydride occurred at 187 °C with endothermic reaction, and caused decomposition into C36-type MgNi₂. This hydride had solubility of Ni content and its thermal stability decreased with increasing Ni content.     

Development of a spherical motor driven by electro-magnets

This paper presents a spherical motor driven by electro-magnets that can rotate omnidirectionally with some degrees of rotation angle error independent of rotation direction. The spherical motor is composed of a spherical rotor, a semi-spherical stator, a control PC, a control circuit, and a DC power supply. The rotor has 92 neodymium magnets. On the other hand, 84 electro-magnets are arranged on the stator. Each electro-magnet can be excited to north or south magnetic pole. The control PC calculates the posture of the rotor after a small time interval and generates the pattern of excitation of electro-magnets in order to rotate the rotor to its calculated posture. The results of the performance of the developed spherical motor show that the maximum torque is 0.24 (N·m), the maximum rotation speed is 2.5 (rad/s), and the average error of rotation angle is several degrees.     

Detection of genistein as an estrogenic contaminant of river water in Osaka

The estrogenic activity in water at various localities on Lake Biwa-Yodo River, a representative watershed in Japan, was measured using a recombinant yeast that expresses the human estrogen receptor. The yeast bioassay revealed that the activities of 13 water samples had an average value of 14 pmol/L (3.8 ng/L) (17beta-estradiol equivalent) with a very wide range from 0 to 72 pmol/L (0-19.6 ng/ L), and two of the samples had prominent levels of activity (72 pmol/L (19.6 ng/L) and 56 pmol/L (15.2 ng/L)). We analyzed these two samples with instrumental approaches. A high-performance liquid chromatogram profile showed that the strong activity in one sample, which was collected just downstream of a sewage-treatment plant, would be due to 17beta-estradiol and estrone, whose source is considered to be human urine contained in the effluent of the plant. The activity in the other sample, which was obtained from a tributary river in a primarily residential area with some industrial development (i.e., Osaka City), however, did not correspond to 17beta-estradiol, estrone, or synthetic chemicals known as estrogenic. Analysis of a fraction with estrogenic activity by liquid chromatography-mass spectrometry (LC-MS) provided evidence that the activity in the water sample resulted from the presence of genistein, an isoflavone compound of plant origin.     

Homologous Recombination-Independent Large Gene Cassette Knock-in in CHO Cells Using TALEN and MMEJ-Directed Donor Plasmids

Gene knock-in techniques have rapidly evolved in recent years, along with the development and maturation of genome editing technology using programmable nucleases. We recently reported a novel strategy for microhomology-mediated end-joining-dependent integration of donor DNA by using TALEN or CRISPR/Cas9 and optimized targeting vectors, named PITCh (Precise Integration into Target Chromosome) vectors. Here we describe TALEN and PITCh vector-mediated integration of long gene cassettes, including a single-chain Fv-Fc (scFv-Fc) gene, in Chinese hamster ovary (CHO) cells, with comparison of targeting and cloning efficiency among several donor design and culture conditions. We achieved 9.6-kb whole plasmid integration and 7.6-kb backbone-free integration into a defined genomic locus in CHO cells. Furthermore, we confirmed the reasonable productivity of recombinant scFv-Fc protein of the knock-in cells. Using our protocol, the knock-in cell clones could be obtained by a single transfection and a single limiting dilution using a 96-well plate, without constructing targeting vectors containing long homology arms. Thus, the study described herein provides a highly practical strategy for gene knock-in of large DNA in CHO cells, which accelerates high-throughput generation of cell lines stably producing any desired biopharmaceuticals, including huge antibody proteins.     

New Micromechanics Design Theory for Pseudostrain Hardening Cementitious Composite

The micromechanics design theory has realized random short fiber-reinforced cement composites showing pseudostrain hardening (PSH) behavior with over 5% of strain capacity under tension. Nevertheless, this existing theory currently is limited to specific constituent properties, which does not account for chemical bond and fiber rupture. This article presents a new design theory that eliminates this restriction, achieving fiber rupture type PSH-random short fiber-reinforced cement composites with high-performance hydrophilic fibers like polyvinyl alcohol fibers. Uniaxial tensile tests are conducted employing polyvinyl alcohol fiber composites, the results of which support the validity of the proposed theory. Furthermore, parametric study employing the proposed theory quantitatively evaluates the effects of composite's micromechanics parameters, such as bond strength and fiber strength, on composite performance. This parametric study reveals that continuously increasing the degree of fiber rupture (fiber rupture intensity) enhances the strength performance of composites but not energy performance. However, an optimum rupture intensity exists for maximizing energy performance, which is critical for PSH behavior. The consistency between theoretical predictions and experimental results consequently demonstrates that the proposed theory can be utilized practically as a powerful and comprehensive tool for PSH composite design.     

Bifurcation of burst response in an Amari‐Hopfield neuron pair with a periodic external force

To clarify the mechanism of the information processing in the brain of living organisms, and investigate information coding of a neuron, a reasonable mathematical model of a neuron is needed. Various models have been proposed and analyzed for now, some relationship between bursting response and bifurcations. In this paper, we propose a simple and effective model to realize bursting phenomena in Amari‐Hopfield coupled neurons. In this model, we can constructively design desirable bursting responses. Bifurcation diagrams and some analytical results are given, and a basic design scheme to generate a bursting is shown. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(2): 43–53, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10217     

Cognitions and behavior in asymmetric social dilemmas: A comparison of two cultures.

This study investigated whether cognitions and behavior in an asymmetric social dilemma can be predicted by national culture. Results indicated that, as predicted, groups of decision makers from Japan--a collectivist, hierarchical culture--were more cooperative, expected others to be more cooperative, and were more likely to adopt an equal allocation distribution rule to resolve the dilemma than were groups of decision makers from the US--an individualist, egalitarian culture. An opportunity for communication had a greater impact on expectations of others' behavior in groups of U.S. decision makers than in groups of Japanese decision makers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)