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We report on results of X-ray observations of the unique radio pulsar/Be star binary PSR B1259?63, obtained using the ASCA satellite two weeks before, during , and two weeks after the pulsar's most recent periastron passage on January 9, 1994. The source was detected at all three epochs, with an X-ray luminosity in the 1{10 keV band of 110 34 (d=2 kpc) 2(More)
We have studied the spectral and rapid variations of GS 2023+338 using all Ginga (LAC) data available of this source. We used colour-colour and hardness-intensity diagrams to study the spectral behaviour and for the variability behaviour we used the FFT-technique to obtain power spectra, the energy dependence of the variability and the energy dependence of(More)
Axon guidance involves multiple second messenger signal transduction pathways. Although each signal transduction pathway has been characterized, only a few studies have examined crosstalk between these cascades. Here, we applied a simultaneous second messenger imaging method to the growth cone and demonstrated correlations between cAMP, cGMP, and Ca(2+).(More)
We evaluated the anticonvulsive effects of phenobarbital (PB) and zonisamide (ZNS) in the EL mouse, a strain that is highly susceptible to seizures. The concentration of each agent was analyzed in the serum and brain. PB suppressed the seizures dose-dependently, whereas even the higher dose of ZNS was ineffective in achieving a complete suppression. Serum(More)
We present results from quantitative modeling and spectral analysis of the high mass X-ray binary system Vela X-1 obtained with the Chandra High Energy Transmission Grating Spectrometer. The observations cover three orbital phase ranges within a single binary orbit. The spectra exhibit emission lines from H-like and He-like ions driven by photoionization,(More)
We present the results of a systematic study using ASCA of the ionization state for six " mixed-morphology " supernova remnants (MM SNRs): IC 443, W49B, W28, W44, 3C391, and Kes 27. MM SNRs show centrally filled thermal X-ray emission, which contrasts to shell-like radio morphology, a set of characteristics at odds with the standard model of SNR evolution(More)
We report the detection of a fully-resolved, Compton-scattered emission line in the X-ray spectrum of the massive binary GX 301−2 obtained with the High Energy Transmission Grating Spectrometer onboard the Chandra X-ray Observatory. The iron Kα fluorescence line complex observed in this system consists of an intense narrow component centered at an energy of(More)
We present the results of X-ray spatial and spectral studies of the " mixed-morphology " supernova remnant IC 443 using ASCA. IC 443 has a center-filled image in X-ray band, contrasting with the shell-like appearance in radio and optical bands. The overall X-ray emission is thermal, not from a synchrotron nebula. ASCA observed IC 443 three times, covering(More)
The accretion-powered pulsar Her X-1 was observed with Suzaku twice in its main-on state, on 2005 October 5-6 and 2006 March 29-30, for a net exposure of 30.5 ks and 34.4 ks, respectively. In the 2005 and 2006 observations, the source was detected at an average 10-30 keV intensity of 290 mCrab and 230 mCrab, respectively. The intrinsic pulse period was(More)