High-speed MQW electroabsorption optical modulators integrated withlow-loss waveguides

An MQW electro-absorption optical modulator integrated with low-loss input and output waveguides is proposed to achieve larger modulation bandwidth with a shorter modulation region, keeping the total device length large enough for easy fabrication and packaging. A fabricated 1-mm-long modulator with a modulation-region length of 50 μm shows a low insertion loss (7 dB), low driving voltage (V_{10 dB}=2.6 V), and large modulation bandwidth f_{3 dB} =40 (GHz) extrapolated from measurements up to 20 GHz. This modulator is suitable for application to ultra-high-speed fiber transmission systems     

Fluorine-18 labeled 6-fluoro-L-dopa: systematization and evaluation of its usefulness

6-[18F]Fluoro-L-dopa (L-3,4-dihydroxy-6-[18F]fluorophenylalanine; 6-[18F]FDPA) is useful to assess presynaptic dopamine metabolism in central nervous system. In this paper, we report on the usefulness of the 6-[18F]FDOPA synthesis system developed for the routine synthesis. This system consists of the 6-[18F]FOPA synthesis and the separation units in conjunction with controller using a personal computer. The synthesis time of 6-[18F]FDOPA was 73 minutes. The typical yield and specific activity were 1.4-2.4 GBq and 244-270 MBq/mumol at the end of synthesis, respectively, under the irradiation condition of 50 microA for 130 minutes. The radiochemical yields of 6-[18F]FDOPA were 31.3-38.7% based on the [18F]acetylhypofluorite, and the results were affected with the condition of potassium acetate (AcOK) to produce gaseous [18F]acetylhypofluorite. This system is useful for the routine production of 6-[18F]FDOPA because of its high yield and high specific activity while maintaining AcOK in good condition, and decreasing the radiation exposure for chemist.     

Prevalence and correlates of major depressive episode among the elderly in a community in Japan

A random sample of 205 persons from a community of about 45,500 residents, aged 65 years or older, in a city in Japan, was surveyed using an interview schedule including a structured psychiatric interview to analyze prevalence of major depressive episode (DSM-III-R). A total of 157 (77%) participated in the study. Results were as follows: 1) The Prevalence of major depressive episode during the past 6 months was 2.1% for males and 3.7% for females among the 155 respondents who completed the psychiatric interview. 2) Significantly higher prevalence during the past 6 months was observed in those who were physically inactive in the past year than in those physically active (p < 0.05). 3) Levels of satisfaction with available social support were significantly lower in those who experienced major depressive episode during the past six months than in those who experienced no depressive episode (p < 0.05). 4) Levels of life satisfaction (PGC scale score) and cognitive functioning were significantly lower in those experienced major depressive episode during the past six months than in those who experienced no depressive episode (p < 0.05).     

Heterogeneous distributions of histamine H3, dopamine D1 and D2 receptors in rat brain

The changes of the histamine H3 and dopamine D1 or D2 receptor binding sites induced by quinolinic acid treatment were studied in order to discriminate the comparative distribution. This treatment resulted in similar decreases in histamine H3 and dopamine D1 receptor binding sites in the striatum and ipsilateral substantia nigra. Dopamine D2 receptor binding sites were relatively well conserved, whereas H3 receptors decreased considerably. These results suggest that histamine H3 and dopamine D1 receptor binding sites are localized on the striatonigral projection neurones which are together sensitive to quinolinic acid, and that the distributional compartment of dopamine D2 receptor binding sites is quite different from those of histamine H3 and dopamine D1 receptors.     

Characterization of almond alpha-mannosidase and its application for structure analysis of sugar chain

Almond alpha-mannosidase was purified by separation on columns of DEAE-Sephadex A50 and hydroxyapatite, and characterized. Its optimum pH was approximately 3.8. It was also shown to be stable from pH 6 to 8. Its activity was stable up to 60 degrees C. The thermostability of almond alpha-mannosidase at 73 degrees C appeared to be superior to that of jack bean a-mannosidase. We examined the substrate specificity of the former toward high-mannose-type N-glycan Man9GlcNAc2, and showed that the deduced trimming pathway was more diverse than that of the latter. We could use almond alpha-mannosidase as well as jack bean alpha-mannosidase for analysis of sugar chain structures.     

High-performance computing of wind turbine aerodynamics using isogeometric analysis

In this article we present a high-performance computing framework for advanced flow simulation and its application to wind energy based on the residual-based variational multiscale (RBVMS) method and isogeometric analysis. The RBVMS formulation and its suitability and accuracy for turbulent flow in a moving domain are presented. Particular emphasis is placed on the parallel implementation of the methodology and its scalability. Two challenging flow cases were considered: the turbulent Taylor–Couette flow and the NREL 5 MW offshore baseline wind turbine rotor at full scale. In both cases, flow quantities of interest from the simulation results compare favorably with the reference data and near-perfect linear parallel scaling is achieved.     

Optical Lattice Clock

Latest progress in optical atomic clocks is so rapid that serious discussions toward the redefinition of the second is initiated. Besides single ion clocks developed since early 1980s, optical lattice clocks just invented a decade ago are one of strong candidates as a method to realize the revised definition. The current situation of this emerging method of optical clocks is briefly described.     

Wideband Planar Folded Dipole Antenna With Self-balanced Impedance Property

A planar folded dipole antenna that exhibits wideband characteristics is proposed. The antenna has simple planar construction without a ground plane and is easy to be assembled. Parameter values are adjusted in order to obtain wideband properties and compactness by using an electromagnetic simulator based on the method of moments. An experimental result centered at 1.7 GHz for 50 impedance matching shows that the antenna has bandwidth over 55% . The gains of the antenna are almost constant (2 dBi) in this frequency band and the radiation patterns are very similar to those of a normal dipole antenna. It is also shown that the antenna has a self-balanced impedance property in this frequency band.     

Parallel programming in MIMD type parallel systems using transputer and i860 in physical simulations

Parallel programming and calculation performance were examined by using two types of MIMD parallel systems, that is, a transputer (T800) network and iPSC/860. Some interface subroutines were developed to apply the programs parallelized by using a transputer network to iPSC/860. Compatibility and performance of parallelized programs are discussed.