646 research outputs found
In Orbit Performance of the MAXI/SSC onboard the ISS
We report here the in orbit performance of the CCD camera (MAXI/SSC) onboard
the International Space Station (ISS). It was commissioned in August, 2009.
This is the first all-sky survey mission employing X-ray CCDs. It consists of
32 CCDs each of which is 1 inch square. It is a slit camera with a field of
view of 1deg.5x 90deg and scans the sky as the rotation of the ISS. The CCD on
the SSC is cooled down to the working temperature around -60degC by the
combination of the peltier cooler, a loop heat pipe and a radiator. The
standard observation mode of the CCD is in a parallel sum mode (64-binning).
The CCD functions properly although it suffers an edge glow when the Sun is
near the field of view (FOV) which reduces the observation efficiency of the
SSC down to about 30%. The performance of the CCD is continuously monitored
both by the Mn-K X-rays and by the Cu-K X-rays. There are many sources
detected, not only point sources but extended sources. Due to the lack of the
effective observation time, we need more observation time to obtain an extended
emission analysis extraction process.Comment: 15 pages 11 figure
Can late gadolinium enhancement on cardiovascular magnetic resonance describe cardiac involvement in patients with systemic sarcoidosis and/or suspect of cardiac involvement of sarcoidosis with cardiac symptoms?
2011 SCMR/Euro CMR Joint Scientific Sessions Nice, France. 3-6 February 201
Dose T2-weighted short TI inversion recovery images on cardiac magnetic resonance reflect disease activity in cardiac involvement of sarcoidosis patients?
The 76th Annual Scientific Meeting of the Japanese Circulation Society 2012年03月18日 Fukuok
Solitary Cardiac Metastasis of Hepatocellular Carcinoma
Cardiac metastasis originating from hepatocellular carcinoma (HCC) is a rare condition with a poor prognosis. No therapeutic standards for cardiac metastasis originating from HCC have been established. At 19 months after a curative hepatectomy, a 64-year-old Japanese hepatitis B virus-positive male patient experienced solitary cardiac metastasis originating from HCC. The cardiac tumor was discovered in the right ventricle. The patient received three courses of radiotherapy and chemotherapy and survived > 3 years after the initial diagnosis of cardiac metastasis. His case demonstrates that radiotherapy combined with chemotherapy can be an effective treatment for cardiac metastasis
Posttraumatic Cranial Cystic Fibrous Dysplasia
A 14-year-old was girl admitted to our hospital with a subcutaneous mass of the occipital head. The mass had grown for 6 years, after she had sustained a head injury at the age of 6, and was located directly under a previous wound. Skull X-ray Photograph (xp), computed tomography (CT), and magnetic resonance imaging (MRI) showed a bony defect and cystic changes in the skull corresponding to a subcutaneous mass. Bone scintigraphy revealed partial accumulation. The patient underwent total removal of the skull mass, and the diagnosis from the pathological findings of the cyst wall was fibrous dysplasia (FD). The radiographic findings for cystic cranial FD can be various. Progressive skull disease has been reported to be associated with head trauma, but the relationship between cranial FD and head trauma has not been previously reported. Previous studies have suggested that c-fos gene expression is a key mechanism in injury-induced FD
MAXI GSC observations of a spectral state transition in the black hole candidate XTE J1752-223
We present the first results on the black hole candidate XTE J1752-223 from
the Gas Slit Camera (GSC) on-board the Monitor of All-sky X-ray Image (MAXI) on
the International Space Station. Including the onset of the outburst reported
by the Proportional Counter Array on-board the Rossi X-ray Timing Explorer on
2009 October 23, the MAXI/GSC has been monitoring this source approximately 10
times per day with a high sensitivity in the 2-20 keV band. XTE J1752-223 was
initially in the low/hard state during the first 3 months. An anti-correlated
behavior between the 2-4 keV and 4-20 keV bands were observed around January
20, 2010, indicating that the source exhibited the spectral transition to the
high/soft state. A transient radio jet may have been ejected when the source
was in the intermediate state where the spectrum was roughly explained by a
power-law with a photon index of 2.5-3.0. The unusually long period in the
initial low/hard state implies a slow variation in the mass accretion rate, and
the dramatic soft X-ray increase may be explained by a sudden appearance of the
accretion disk component with a relatively low innermost temperature (0.4-0.7
keV). Such a low temperature might suggest that the maximum accretion rate was
just above the critical gas evaporation rate required for the state transition.Comment: Publication of Astronomical Society of Japan Vol.62, No.5 (2010) [in
print
Bright X-ray flares from the BL Lac object Mrk 421, detected with MAXI in 2010 January and February
Strong X-ray flares from the blazar Mrk 421 were detected in 2010 January and
February through the 7 month monitoring with the MAXI GSC. The maximum 2 -- 10
keV flux in the January and February flares was measured as 120 +- 10 mCrab and
164 +- 17 mCrab respectively; the latter is the highest among those reported
from the object. A comparison of the MAXI and Swift BAT data suggests a convex
X-ray spectrum with an approximated photon index of about 2. This spectrum is
consistent with a picture that MAXI is observing near the synchrotron peak
frequency. The source exhibited a spectral variation during these flares,
slightly different from those in the previous observations, in which the
positive correlation between the flux and hardness was widely reported. By
equating the halving decay timescale in the January flare, s, to the synchrotron cooling time, the magnetic field was
evaluated as B = 0.045 G , where is the jet
beaming factor. Assuming that the light crossing time of the emission region is
shorter than the doubling rise time, s,
the region size was roughly estimated as cm
. These are consistent with the values previously reported. For
the February flare, the rise time, s, gives a
loose upper limit on the size as cm ,
although the longer decay time s, indicates
B = 0.015 G , which is weaker than the previous results.
This could be reconciled by invoking a scenario that this flare is a
superposition of unresolved events with a shorter timescale.Comment: 14 pages, 4 figures, accepted for PASJ (Vol. 62 No. 6
A Large X-ray Flare from a Single Weak-lined T Tauri Star TWA-7 Detected with MAXI GSC
We present a large X-ray flare from a nearby weak-lined T Tauri star TWA-7
detected with the Gas Slit Camera (GSC) on the Monitor of All-sky X-ray Image
(MAXI). The GSC captured X-ray flaring from TWA-7 with a flux of
ergs cm s in 2--20 keV band during the scan
transit starting at UT 2010-09-07 18:24:30.The estimated X-ray luminosity at
the scan in the energy band is 3 ergs s,indicating that
the event is among the largest X-ray flares fromT Tauri stars.Since MAXI GSC
monitors a target only during a scan transit of about a minute per 92 min
orbital cycle, the luminosity at the flare peak might have been higher than
that detected. At the scan transit, we observed a high X-ray-to-bolometric
luminosity ratio, log = ; i.e., the
X-ray luminosity is comparable to the bolometric luminosity. Since TWA-7 has
neither an accreting disk nor a binary companion, the observed event implies
that none of those are essential to generate such big flares in T Tauri stars.Comment: 4 pages, 2 figures, 1 table accepted for publication in PAS
Safety of Surgical Treatment for Elderly Patients with Gallbladder Carcinoma
Gallbladder carcinoma (GBC) is a common malignancy with a poor prognosis. With the average life expectancy increasing globally, the incidence of GBC is predicted to increase as well. We investigated the safety and feasibility of surgical treatment for elderly patients with GBC. We retrospectively compared clinical pathological data and treatment outcomes in 45 consecutive GBC patients (23 patients ≥ 75 years [elderly group] and 22 patients < 75 years [younger group]) who underwent curative resection at the Iwakuni Center from January 2008 to December 2017. The proportion of preoperative comorbidities and anticoagulant use was significantly higher in the elderly group. The American Society of Anesthesiologists score was higher in the elderly versus the younger group, and the elderly group had significantly shorter operation times. Reduced activities of daily living was more common in the elderly versus younger group. The percentage of radical resection and overall 3-year survival (66.6% younger vs. 64.4% elderly) were similar between the groups. Controlling Nutritional Status (CONUT) score ≥ 3 and R0 resection were identified as prognostic factors for overall survival rate among all patients. After careful patient selection
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