The brainstem and thalamic lesions in dentatorubral-pallidoluysian atrophy: an MRI study

We studied the frequency and characteristics of brainstem and thalamic lesions in dentatorubral-pallidoluysian atrophy using MRI. Of 15 subjects diagnosed by DNA analysis, 13 had lesions in the pontine base, nine in the midbrain, and five in the thalamus. Lesions were correlated positively with the patient's age, but not with neurologic features or numbers of CAG repeats. Patients with Machado-Joseph disease or spinocerebellar ataxia 1 did not show these characteristic lesions.     

Cast and mold polymerization of organic glass by irradiation from fluid and soft gel prepolymers

Casting and mold polymerization processes were investigated by means of γ-irradiation of methyl methacrylate prepolymer systems containing some quantity of polyfunctional monomers. Some physical properties, such as supercooling tendency and temperature dependence of viscosity and relaxation time in fluid prepolymers, were measured and related to cast polymerization at low temperatures. It was found that free-state casting with no frame or mold was possible using viscous states of prepolymer in the supercooled state. Furthermore, efficient mold polymerization using soft gel prepolymer was studied. That is, plastic soft gel prepolymer was prepared conveniently by irradiation of fluid prepolymer, then molded into spherical or nonspherical curved surface shapes, and curved by reirradiation. Polymerization and gelation behavior of soft gel prepolymer and penetration degree of prepolymer as a measure of plasticity of gel were studied in relation to prepolymer composition and irradiation condition.     

Toward a quizmaster robot for speech-based multiparty interaction

This paper presents an interactive quizmaster robot that can manage a multiparty speech-based quiz game. The basic flow of the quiz game is that (1) the robot reads a question, (2) one or more players answer it, and (3) the robot judges the correctness of the answers. We categorize such speech-based quiz games into school-type interaction and auction-type interaction. The former asks players to say ‘Yes’ to get the right to answer before answering a question and the latter allows players to directly answer a question without any advance notice. To realize such interaction, the robot needs the capability of recognizing utterances from multiple people using its own microphones (i.e. ears), even if those utterances are made simultaneously. To cope with such situations, the robot estimates which player made the fastest utterance and recognizes it by localizing and separating a mixture of audio signals. Experiments were conducted to evaluate the success rates of the fastest player identification and speech recognition. The results showed that the robot could identify the fastest speakers with a success rate of 90.0% more accurately than humans when only one speaker slightly preceded the other speakers. We found that although the success rate of speech recognition for the fastest speakers did not reach that of humans, the robot attains amusing quiz game interaction.     

Electronic ferroelectricity from charge ordering in RFe(2)O(4)

We report our recent discovery of novel ferroelectricity arising from the polar ordering of Fe(3)+ and Fe(2)+ in a mixed valence triangular lattice oxide LuFe(2)O(4), where the electric polarization is not a result of ionic displacement. The polar ordering of Fe(3)+ and Fe(2)+ was confirmed with a resonant x-ray scattering study in SPring-8. The origin of such ordering is the competitive interaction between Fe(3)+ and Fe(2)+ in the triangular lattice, i.e., the charge frustration. The polar superlattice of Fe(3)+ and Fe(2)+ develops below 350 K, where the electric polarization appears. The ferroelectricity arising from the polar charge ordering or the polar electron distribution may have great potential for the future application of ferroelectrics.     

Preparation of crosslinked carboxymethylated chitin derivatives by irradiation and their sorption behavior for copper(II) ions

To obtain highly efficient adsorbents that were insoluble in acidic and basic aqueous solutions, we synthesized new types of crosslinked chitin derivatives (carboxymethylchitin and carboxymethylchitosan) with ionizing radiation, and we investigated the sorption of Cu(II) ions onto these crosslinked chitin derivatives. Sorption kinetic studies indicated the rapid removal of copper(II) ions from the aqueous solutions. Also, isothermal sorption data revealed that Cu(II) was removed by these crosslinked carboxymethylated chitin derivatives with high efficiency. Sorption isothermal data were interpreted well by the Langmuir equation. The uptake of Cu(II) ions was 161 mg/g on crosslinked carboxymethylchitin and 172 mg/g on crosslinked carboxymethylchitosan at pH 5.5. A low pH was favorable for Cu(II) desorption. The Cu(II) ions were desorbed from the crosslinked matrix rapidly and completely after a treatment in a diluted HCl solution, and at the same time, the adsorbents were regenerated to be used again to adsorb heavy metal ions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 556–562, 2004     

Effect of Feed Liquid Temperature on the Structural Morphologies of d-Limonene Microencapsulated Powder and Its Preservation

ABSTRACT:  The influence of the feed liquid temperature of the spray drying was investigated on the particle morphology (vacuole size and shell thickness of hollow particle) and the stability of encapsulated  d -limonene. The feed liquid was the mixture of  d -limonene emulsified in a wall material of blending gum arabic (GA) and maltodextrin (MD) at the mass ratio of 1 : 2, and the liquid temperature was varied from 40 to 80 °C. The percentage of the hollow particle in the spray-dried powder was over 40% and slightly increased with the rising of the feed temperature. Hollow particles have shells of different thickness, which was estimated from the image with a confocal laser scanning microscope (CLSM). The shell thickness increased with the increase in the feed temperature. This finding was qualitatively supported by scanning electron microscopy (SEM) images of the fractured particles. In addition, release and oxidation stability of encapsulated  d -limonene were measured at constant temperature and humidity. The powder at high temperature of feed has higher stability for release and oxidation of  d -limonene than that at a lower feed temperature. The result may partly be attributed to the increase of the shell thickness of the particle at a higher feed temperature. The thicker shell wall possibly served as the barrier of the flavor release and the diffusion of oxygen and moisture from the surrounding environment.     

High-field magnetization of a Dy2Fe14Si3 single crystal

The magnetization of a Dy₂Fe₁₄Si₃ single crystal was measured at 4.2 K in pulsed fields up to 51 T along the principal axes. The compound orders ferrimagnetically at 500 K, has a spontaneous magnetic moment of 8 μ_B/f.u. (at 4.2 K) and exhibits a very large magnetic anisotropy, 〈1 0 0〉 being the easy axis. In fields applied along the 〈1 0 0〉 and 〈1 2 0〉 axes, field-induced phase transitions are observed at 33 T and at 39 T, respectively. The c-axis magnetization curve crosses the easy-axis curve at 19 T. At higher fields, for all directions, the magnetization continues to increase due to further bending of the sublattice moments. Temperature evolution of magnetic anisotropy and magnetic hysteresis are discussed as well.