Actively mode-locked strained-InGaAsP multiquantum-well lasersintegrated with electroabsorption modulators and distributed Braggreflectors

This paper describes picosecond pulse generation at 20 Gb/s by monolithic mode-locked lasers integrated with electroabsorption modulators and distributed Bragg reflectors. The electroabsorption modulator using strained-InGaAsP multiquantum wells acts as a pulse shortening gate when a sinusoidal voltage is driven at a large reverse bias voltage. To obtain transform-limited picosecond pulses, the required spectral bandwidth of the distributed Bragg reflector is estimated. Pulse generation around 4 ps with a time-bandwidth product of 0.5 has been performed at a repetition rate of 20 GHz. Driving conditions of the modulator, such as bias voltage and modulation frequency, are investigated. It is shown that an increase in the intensity noise is the main factor limiting performance     

Visualization of the interaction between blood vessels and podocytes in the mouse embryonic glomerulus using a barium-infusion method for scanning electron microscopy

The present study revealed three dimensionally the formation of epithelial cells and vascular capillaries in glomeruli of the kidney of the mouse embryo. Barium sulphate was infused through the umbilical vessel of 16.5-17.5-day embryos and the backscattered electron (BSE) image and the secondary electron (SE) image of the identical area of glomeruli were obtained by scanning electron microscopy (SEM). The BSE images directly showed the vascular structure of the glomerulus, while the SE images showed a developmental process of podocytes from epithelial cells. Podocytes were more closely located to the vascular capillary than other epithelial cells. These findings were compared with those obtained in the resin cast model of glomeruli. Thus, the metal infusion-SEM method described here can trace the process of formation of urine filtration barrier in the mouse embryonic glomerulus.     

Low Frequency Susceptibility of High-Density bcc Solid 3He in the Paramagnetic and Nuclear-Ordered States

We have measured the AC magnetic susceptibility and static magnetization of high-density bcc solid ³ He through the nuclear-ordering transition. The susceptibility in the paramagnetic state strongly depends on the frequency of the measuring field. Near the transition temperature a sharp peak in the real part of the AC susceptibility and an abrupt depression in the imaginary part are observed. The transition temperature indicated by the AC susceptibility is higher than that derived from static magnetization. We analyzed the new behavior in the susceptibility in terms of the spin relaxation between the Zeeman system and the exchange system. The relaxation time in the energy flow in the two systems is in the range of milliseconds in the paramagnetic state, and decreases drastically by two orders of magnitude in the ordered state. The relaxation time in the paramagnetic state is interpreted as due to exchange narrowing, while in the ordered state is explained to be the drift time of the spin wave limited by the size of the sample grown in the pores of the sintered silver. The ordering temperature is given as a function of molar volume in the entire range of the bcc phase.     

Two cases of repeatedly recurrent atypical thymoma

Two cases of repeatedly recurrent thymoma with myasthenia gravis are detailed here. A 41-year-old woman had 5 recurrent thymomas, including local recurrences and lumbar and lung metastases; she was alive at the time of this writing, which was 22 years after her first surgery. A 36-year-old man had 3 recurrent thymomas, including local recurrence, dissemination, and lung metastasis; he was alive at the time of this writing, which was 16 years after his first surgery. Both recurrent lesions were diagnosed as "atypical thymoma" with moderate nuclear atypia. The patients with atypical thymoma must be followed up carefully due to a possible recurrence. Surgical treatment with chemoradiotherapy can lengthen their survival.     

Development and evaluation of the interferometric monitor for greenhouse gases: a high-throughput fourier-transform infrared radiometer for nadir earth observation

The interferometric monitor for greenhouse gases (IMG) was the precursor of the high-resolution Fourier-transform infrared radiometer (FTIR) onboard a satellite for observation of the Earth. The IMG endured the stress of a rocket launch, demonstrating that the high-resolution, high-throughput spectrometer is indeed feasible for use onboard a satellite. The IMG adopted a newly developed lubricant-free magnetic suspension mechanism and a dynamic alignment system for the moving mirror with a maximum traveling distance of 10 cm. We present the instrumentation of the IMG, characteristics of the movable mirror drive system, and the evaluation results of sensor specifications during space operation.     

Motional coherency in chain dynamics of polybutadiene studied by molecular dynamics simulations

Molecular dynamics simulations of 1,4-polybutadiene in bulk amorphous state were performed. Results were compared with the recent neutron spin-echo measurements. To investigate motional coherency the relaxation rates for the collective and self-motions, the collective and self-relaxation rates, were evaluated for the short and long time regimes of the normalized intermediate scattering functions. The scattering vector dependence of the collective relaxation rates estimated for both fast and slow processes indicated a minimum at scattering vector q = 1.5 Å⁻¹, corresponding to the position of a peak in the static structure factor. The self-relaxation rates increased monotonously with q. A phenomenon known as de Gennes narrowing was reproduced well in the simulation and found to be originated from the inter-molecular correlation. The collective relaxation rate evaluated for fast process appeared to modulate around a peak of q = 2.9 Å⁻¹, corresponding to the intra-molecular correlation.     

Serological survey of antibody to Neospora caninum in Japanese dogs

Prevalence of antibody to Neospora caninum (NC) in Japanese dogs were examined. The antibody was positive in 15 of 48 dogs (31.3%) reared in the dairy farms that had case of the abortions due to NC infection or had the cattle seropositive to NC, whereas the prevalence was 7.1% (14 of 198 dogs) among the dogs kept in urban areas. In one dog breeder, all 17 Shetland sheepdogs older than 7 months were seropositive, and one pup was diagnosed as neosporosis 2 months before the first serological examination. The antibody titers of the dogs kept at this breeder were almost unchanged for 1.5 years. Serological evidence of the dogs in the dairy farms and urban areas indicates the transmission of NC between dogs and cattle. Also serological results of the dogs in one breeder may suggest the potential horizontal transmission among dogs.     

Pulmonary vasodilator response to adenosine triphosphate-sensitive potassium channel activation is attenuated during desflurane but preserved during sevoflurane anesthesia compared with the conscious state

BACKGROUND: The objective of this study was to investigate the effects of sevoflurane and desflurane anesthesia on the pulmonary vasodilator response to the adenosine triphosphate-sensitive potassium channel agonist, lemakalim, compared with the response measured in the conscious state. In addition, the authors assessed the extent to which sympathetic alpha1-adrenoreceptor inhibition and cyclooxygenase pathway inhibition modulate the vasodilator response to lemakalim. METHODS: Twenty-four conditioned male mongrel dogs were chronically instrumented to measure the left pulmonary vascular pressure-flow relationship. After preconstriction with the thromboxane analogue, U46619, dose-response relationships to lemakalim were assessed on separate days in the conscious state and during sevoflurane (approximately 3.5% end-tidal) and desflurane (approximately 10.5% end-tidal) anesthesia (approximately 1.5 minimum alveolar concentration for each anesthetic agent). The effects of sympathetic alpha1-adrenoreceptor inhibition (prazosin) and cyclooxygenase inhibition (indomethacin) on the pulmonary vasodilator response to lemakalim also were assessed in the conscious and desflurane-anesthetized states. RESULTS: Neither sevoflurane nor desflurane had a net effect on the baseline left pulmonary vascular pressure-flow relationship compared with the conscious state. The magnitude of the pulmonary vasodilator response to lemakalim was preserved during sevoflurane anesthesia but was attenuated (P < 0.05) during desflurane anesthesia compared with the conscious state. The attenuated lemakalim-induced vasodilator response during desflurane anesthesia was partially reversed (P < 0.05) by pretreatment with prazosin but not indomethacin. CONCLUSION: These results indicate that adenosine triphosphate-sensitive potassium channel-mediated pulmonary vasodilation is preserved during sevoflurane anesthesia but is attenuated during desflurane anesthesia. The attenuated response to adenosine triphosphate-sensitive potassium channel activation during desflurane anesthesia is partially mediated by reflex sympathetic alpha1-adrenoreceptor vasoconstriction.