64 research outputs found

    Suzaku observations of the Hydra A cluster out to the virial radius

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    We report Suzaku observations of the northern half of the Hydra A cluster out to ~1.4 Mpc, reaching the virial radius. This is the first Suzaku observations of a medium-size (kT ~3 keV) cluster out to the virial radius. Two observations were conducted, north-west and north-east offsets, which continue in a filament direction and a void direction of the large-scale structure of the Universe, respectively. The X-ray emission and distribution of galaxies elongate in the filament direction. The temperature profiles in the two directions are mostly consistent with each other within the error bars and drop to 1.5 keV at 1.5 r_500. As observed by Suzaku in hot clusters, the entropy profile becomes flatter beyond r_500, in disagreement with the r^1.1 relationship that is expected from accretion shock heating models. When scaled with the average intracluster medium (ICM) temperature, the entropy profiles of clusters observed with Suzaku are universal and do not depend on system mass. The hydrostatic mass values in the void and filament directions are in good agreement, and the Navarro, Frenk, and White universal mass profile represents the hydrostatic mass distribution up to ~ 2 r_500. Beyond r_500, the ratio of gas mass to hydrostatic mass exceeds the result of the Wilkinson microwave anisotropy probe, and at r_100, these ratios in the filament and void directions reach 0.4 and 0.3, respectively. We discuss possible deviations from hydrostatic equilibrium at cluster outskirts. We derived radial profiles of the gasmass- to-light ratio and iron-mass-to-light ratio out to the virial radius. Within r_500, the iron-mass-to-light ratio of the Hydra A cluster was compared with those in other clusters observed with Suzaku.Comment: 16 pages, 15 figures; Accepted for publication in PAS

    Idiopathic pneumoperitoneum after trauma

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    Intra-abdominal free gas is a finding of extra-intestinal gas in the abdominal cavity on radiography or CT, mainly suggesting gastrointestinal perforation and necessitating emergency surgery. Idiopathic pneumoperitoneum is diagnosed when there is no obvious gastrointestinal perforation, but there is presence of free gas in the abdominal cavity with an unidentifiable cause. Herein, we report a case of idiopathic pneumoperitoneum secondary to high-energy trauma following a car rollover accident. A 95-year-old man was transferred to our clinic after a car-to-car rollover accident. He had abrasions on his right upper arm and left abdomen that appeared to be the result of the accident ; however, no other apparent traumatic injuries were noted. There was no pain in the abdomen, and peritoneal irritation symptoms were also not noted. A CT scan showed fine free air. Although idiopathic pneumoperitoneum could not be ruled out, considering the patient’s background and the possibility of traumatic small bowel perforation, emergency surgery was performed. A thorough search of the abdominal cavity was performed ; however, the surgery was completed without an obvious perforation site. Idiopathic pneumoperitoneum should be considered as a differential disease in cases who have free air on abdominal CT but clinically lack obvious inflammatory reaction findings

    Suzaku X-ray Follow-up Observation of Weak-lensing-detected Halos in the Field around ZwCl0823.2+0425

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    We present the results of Suzaku X-ray follow-up observation of weak-lensing-detected halos in the field around galaxy cluster ZwCl0823.2+0425. We clearly detected X-ray emission associated with most of these halos and determined their detailed physical parameters such as X-ray luminosity, temperature, and metal abundance, for the first time. We find that the X-ray luminosity - temperature relation for these halos agrees with former typical results. With mass determined from the weak gravitational lensing data, the mass-temperature relation for them is also investigated and found to be consistent with the prediction from a simple self-similar model and results of the previous studies with both lensing and X-ray data. We would like to emphasize that the self-similar scaling relation of mass and temperature is shown here for the first time using a weak-lensing selected sample, whereas previous studies of the mass scaling relation used X-ray-selected samples of clusters. Therefore, our study demonstrates importance of X-ray follow-up observations of shear-selected clusters, and shows that a joint X-ray and lensing analysis will be crucial for clusters discovered by the forthcoming weak-lensing surveys, such as the one planned with Subaru/Hyper-Suprime-Cam.Comment: 20 pages, 13 figures, accepted for publication in PAS

    Clinical significance of PMI with GC patients

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    Aim : We investigated whether preoperative or postoperative inflammatory markers and psoas muscle index (PMI), and their change after surgery, could predict postoperative recurrence in gastric cancer (GC). Methods : Thirty-five patients who underwent curative gastrectomy for pStage II and III GC were retrospectively reviewed. The relationship between neutrophil–lymphocyte ratio (NLR), prognostic nutritional index (PNI), Glasgow Prognostic Score (GPS), and PMI, as well as postoperative recurrence, was analyzed presurgery and at 6 months after surgery. Results : In the preoperative data, there was a significant association between postoperative recurrence and high NLR, low total protein, low albumin, low PNI, and high GPS. In the data from 6 months after surgery, there was a significant association between postoperative recurrence and high NLR, high C-reactive protein, and high GPS. The reduction in PMI at 6 months after surgery relative to preoperative data was significantly greater in the cases with recurrence than in those without recurrence. No patients whose PMI increased compared with presurgery had recurrence. Conclusions : The postoperative reduction in PMI at 6 months after surgery relative to presurgery could be a predictive marker of recurrence after curative gastrectomy for patients with pStage II and III GC

    Treatment for recurrence after esophagectomy

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    Background : With regard to the recurrence of esophageal cancer after surgery, the prognosis has improved with the progress of multimodal perioperative treatment. In this study, the recurrence pattern, treatment method, and prognosis of recurrent cases following esophageal cancer surgery were retrospectively examined. Materials and Methods : Three hundred seven patients with histologically proven squamous cell carcinoma, adenocarcinoma, and others were enrolled in the study. With respect to clinicopathologic factors and recurrence patterns, recurrence risk factors, recurrence period, treatment for recurrence, and prognosis were investigated. Results : Ninety two percent of all recurrent cases were observed within two years after radical esophagectomy. Locoregional recurrence, distant recurrence, and mixed recurrence were observed in 38 (35%), 56 (51%), and 16 (14%) cases, respectively. Patients with lymph node metastasis showed a significantly longer survival in comparison to those with metastasis to other organs (p = 0.0032). When analyzed using the treatment method, patients who underwent surgery (only surgery or additional postoperative chemotherapy) exhibited better survival in comparison to those who underwent other treatments. Discussion : Detailed and strict follow-up within two years are necessary in cases with deeper than muscular invasion, cases with extensive lymph node metastasis, or cases with lymphatic or vascular invasion

    Suzaku Observation of Abell 1689: Anisotropic Temperature and Entropy Distributions Associated with the Large-Scale Structure

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    (Abridged) We present results of Suzaku observations of the intracluster medium (ICM) in Abell 1689, combined with complementary analysis of the SDSS data and weak and strong lensing analysis of Subaru/Suprime-Cam and HST/ACS observations. Faint X-ray emission from the ICM around the virial radius is detected at 4.0 sigma significance. We find anisotropic gas temperature and entropy distributions in cluster outskirts correlated with large-scale structure of galaxies. The high temperature and entropy region in the northeastern (NE) outskirts is connected to an overdense filamentary structure. The outskirt regions in contact with low density void environments have low gas temperatures and entropies, deviating from hydrostatic equilibrium. These results suggest that thermalization of the ICM occurs faster along the filamentary structures than the void regions. A joint X-ray and lensing analysis shows that the hydrostatic mass is 6090\sim60-90% of spherical lensing one but comparable to a triaxial halo mass within errors in 0.6r_{2500} \simlt r \simlt 0.8r_{500}, and that it is significantly biased as low as \simlt60% within 0.4r25000.4r_{2500}, irrespective of mass models. The thermal gas pressure within r500r_{500} is, at most, 50\sim50--60% of the total pressure to balance fully the gravity of the spherical lensing mass, and 30\sim30--40% around the virial radius. Although these constitute lower limits when one considers the possible halo triaxiality, these small relative contributions of thermal pressure would require additional sources of pressure, such as bulk and/or turbulent motions.Comment: 24 pages, 15 figures, 9 tables. Accepted for publication in Ap

    Diffuse radio source candidate in CIZA J1358.9-4750

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    We report on results of our upgraded Giant Metrewave Radio Telescope (uGMRT) observations for an early-stage merging galaxy cluster, CIZA J1358.9-4750 (CIZA1359), in Band-3 (300--500 MHz). We achieved the image dynamic range of 38,000\sim 38,000 using the direction dependent calibration and found a candidate of diffuse radio emission at 4~σrms\sigma_{rms} significance. The flux density of the candidate at 400~MHz, 24.04±2.4824.04 \pm 2.48~mJy, is significantly positive compared to noise, where its radio power, 2.40×10242.40 \times 10^{24}~W~Hz1^{-1}, is consistent with those of typical diffuse radio sources of galaxy clusters. The candidate is associated with a part of the X-ray shock front at which the Mach number reaches its maximum value of M1.7\mathcal{M}\sim 1.7. The spectral index (FνναF_\nu \propto \nu^{\alpha}) of the candidate, α=1.22±0.33\alpha = - 1.22 \pm 0.33, is in agreement with an expected value derived from the standard diffusive shock acceleration (DSA) model. But such a low Mach number with a short acceleration time would require seed cosmic-rays supplied from active galactic nucleus (AGN) activities of member galaxies, as suggested in some other clusters. Indeed, we found seven AGN candidates inside the diffuse source candidate. Assuming the energy equipartition between magnetic fields and cosmic-rays, the magnetic field strength of the candidate was estimated to be 2.1 μ2.1~\muG. We also find head-tail galaxies and radio phoenixes or fossils near the CIZA1359.Comment: 17 pages, 9 figures, Accepted to PAS
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