286 research outputs found
Combined Spectral and Timing Analysis of the Black Hole Candidate MAXI J1659-152 Discovered by MAXI and Swift
We report on X-ray spectral and timing results of the new black hole
candidate (BHC) MAXI J1659-152 with the orbital period of 2.41 hours (shortest
among BHCs) in the 2010 outburst from 65 Rossi X-ray Timing Explorer (RXTE)
observations and 8 simultaneous Swift and RXTE observations. According to the
definitions of the spectral states in Remillard & McClintock (2006), most of
the observations have been classified into the intermediate state. All the
X-ray broadband spectra can be modeled by a multi-color disk plus a power-law
with an exponential cutoff or a multi-color disk plus a Comptonization
component. During the initial phase of the outburst, a high energy cutoff was
visible at 30-40 keV. The innermost radius of the disk gradually decreased by a
factor of more than 3 from the onset of the outburst and reached a constant
value of 35 d_10 cos i^-1/2 km, where d_10 is the distance in units of 10 kpc
and is the inclination. The type-C quasi-periodic oscillation (QPO)
frequency varied from 1.6 Hz to 7.3 Hz in association with a change of the
innermost radius, while the innermost radius remained constant during the
type-B QPO detections at 1.6-4.1 Hz. Hence, we suggest that the origin of the
type-B QPOs is different from that of type-C QPOs, the latter of which would
originate from the disk truncation radius. Assuming the constant innermost
radius in the latter phase of the outburst as the innermost stable circular
orbit, the black hole mass in MAXI J1659-152 is estimated to be 3.6-8.0 M_solar
for a distance of 5.3-8.6 kpc and an inclination angle of 60-75 degrees.Comment: 27 pages, 14 figures, accepted for publication in PAS
Spectral Evolutions in Gamma-Ray Burst Exponential Decays Observed with Suzaku WAM
This paper presents a study on the spectral evolution of gamma-ray burst
(GRB) prompt emissions observed with the Suzaku Wide-band All-sky Monitor
(WAM). By making use of the WAM data archive, 6 bright GRBs exhibiting 7
well-separated fast-rise-exponential-decay (FRED) shaped light curves are
presented and the evaluated exponential decay time constants of the
energy-resolved light curves from these FRED peak light curves are shown to
indicate significant spectral evolution. The energy dependence of the time
constants is well described with a power-law function tau(E) ~ E^gamma, where
gamma ~ -(0.34 +/- 0.12) in average, although 5 FRED peaks show consistent
value of gamma = -1/2 which is expected in synchrotron or inverse-Compton
cooling models. In particular, 2 of the GRBs were located with accuracy
sufficient to evaluate the time-resolved spectra with precise energy response
matrices. Their behavior in spectral evolution suggests two different origins
of emissions. In the case of GRB081224, the derived 1-s time-resolved spectra
are well described by a blackbody radiation model with a power-law component.
The derived behavior of cooling is consistent with that expected from radiative
cooling or expansion of the emission region. On the other hand, the other 1-s
time-resolved spectra from GRB100707A is well described by a Band GRB model as
well as with the thermal model. Although relative poor statistics prevent us to
conclude, the energy dependence in decaying light curve is consistent with that
expected in the former emission mechanism model.Comment: 11 pages, 7 figures, 5 tables. PASJ accepte
Disappearance of lung adenocarcinoma after total en bloc spondylectomy using frozen tumor-bearing vertebra for reconstruction
Purpose: Total en bloc spondylectomy (TES) is a surgical procedure performed to achieve complete resection of an aggressive benign spinal tumor or a malignant spinal tumor. When reconstructing the spine after resection, we have been using liquid nitrogen-frozen resected spine bearing tumor as a bone graft, expecting an immunological response to tumor-specific antigen(s). The purpose of this article is to report a successful treatment case of lung adenocarcinoma metastasis with TES and this cryotherapy. Methods: A 59-year-old male presented with rapid progression of neurological deterioration of the lower limbs due to a spinal metastasis from T8 to T10. The primary lung adenocarcinoma had already been excised under thoracoscopy. The patient underwent TES with reconstruction using frozen tumor-bearing vertebra for the bone graft. Results: One month after surgery, a new nodule appeared at the right middle lobe of the lung. However, we carried out no biopsy of the newly emerged nodule and the patient received no adjuvant chemotherapy or radiotherapy. Six months after surgery, the tumor vanished. No local recurrence or metastasis of the tumor has been observed until now. Conclusions: TES with a liquid nitrogen-frozen tumor specimen could be a promising therapeutic option for cancer patients with spine metastasis. © 2015 Springer-Verlag Berlin HeidelbergEmbargo Period 12 month
Acupuncture Regulates Leukocyte Subpopulations in Human Peripheral Blood
Acupuncture has recently been attracting more and more people throughout the world as an alternative treatment, however little is known about its physiological activities (i.e. immune system). We examined acupuncture both quantitatively and qualitatively by measuring CD-positive cell counts and cytokine expression levels in the blood, to determine the activity of T cells, B cells, macrophages and natural killer (NK) cells. Fifteen milliliters of peripheral blood obtained from 17 healthy volunteers aged 21–51 years, were analyzed using flow cytometry before and after acupuncture treatment. There was a statistically significant increase in the number of CD2+, CD4+, CD8+, CD11b+, CD16+, CD19+, CD56+ cells as well as IL-4, IL-1β and IFN-γ levels in the cells after acupuncture stimulation of meridian points. These observations indicate that acupuncture may regulate the immune system and promote the activities of humoral and cellular immunity as well as NK cell activity. In this article, we discussed how acupuncture regulated leukocyte numbers and functions since they are considered to be potential indicators for evaluating complementary and alternative medicine
Neutrophil S100A9 supports M2 macrophage niche formation in granulomas
慢性炎症「肉芽腫」における好中球の新しい炎症制御系の解明 --M2マクロファージの新たな誘導メカニズム解明--. 京都大学プレスリリース. 2023-02-17.In search of inflammatory Achilles heel. 京都大学プレスリリース. 2023-03-10.Mycobacterium infection gives rise to granulomas predominantly composed of inflammatory M1-like macrophages, with bacteria-permissive M2 macrophages also detected in deep granulomas. Our histological analysis of Mycobacterium bovis bacillus Calmette-Guerin-elicited granulomas in guinea pigs revealed that S100A9-expressing neutrophils bordered a unique M2 niche within the inner circle of concentrically multilayered granulomas. We evaluated the effect of S100A9 on macrophage M2 polarization based on guinea pig studies. S100A9-deficient mouse neutrophils abrogated M2 polarization, which was critically dependent on COX-2 signaling in neutrophils. Mechanistic evidence suggested that nuclear S100A9 interacts with C/EBPβ, which cooperatively activates the Cox-2 promoter and amplifies prostaglandin E2 production, followed by M2 polarization in proximal macrophages. Because the M2 populations in guinea pig granulomas were abolished via treatment with celecoxib, a selective COX-2 inhibitor, we propose the S100A9/Cox-2 axis as a major pathway driving M2 niche formation in granulomas
Spectral Properties of Prompt Emission of Four Short Gamma-Ray Bursts Observed by the Suzaku-WAM and the Konus-Wind
We have performed a joint analysis of prompt emission from four bright short
gamma-ray bursts (GRBs) with the Suzaku-WAM and the Konus-Wind experiments.
This joint analysis allows us to investigate the spectral properties of
short-duration bursts over a wider energy band with a higher accuracy. We find
that these bursts have a high E, around 1 MeV and have a harder
power-law component than that of long GRBs. However, we can not determine
whether these spectra follow the cut-off power-law model or the Band model. We
also investigated the spectral lag, hardness ratio, inferred isotropic
radiation energy and existence of a soft emission hump, in order to classify
them into short or long GRBs using several criteria, in addition to the burst
duration. We find that all criteria, except for the existence of the soft hump,
support the fact that our four GRB samples are correctly classified as
belonging to the short class. In addition, our broad-band analysis revealed
that there is no evidence of GRBs with a very large hardness ratio, as seen in
the BATSE short GRB sample, and that the spectral lag of our four short GRBs is
consistent with zero, even in the MeV energy band, unlike long GRBs. Although
our short GRB samples are still limited, these results suggest that the
spectral hardness of short GRBs might not differ significantly from that of
long GRBs, and also that the spectral lag at high energies could be a strong
criterion for burst classification.Comment: 23 pages, 6 figures, accepted for Publications of the Astronomical
Society of Japa
Reviewing E(sub peak) Relations with Swift and Suzaku Data
In recent years several authors have derived correlations between gamma-ray burst (GRB) spectral peak energy (E(sub peak)) and either isotropic-equivalent radiated energy (E(sub iso)) or peak luminosity (L(sub iso)). Since these relationships are controversial, but could provide redshift estimators, it is important to determine whether bursts detected by Swift exhibit the same correlations. Swift has greatly added to the number of GRBs for which redshifts are known and hence E(sub iso) and L(sub iso) could be calculated. However, for most bursts it is not possible to adequately constrain E(sub peak) with Swift data alone since most GRBs have E(sub peak) above the energy range (15-50 keV) of the Swift Burst Alert Telescope (BAT). Therefore we have analyzed the spectra of 78 bursts (31 with redshift) which were detected by both Swift/BAT and the Suzaku Wide-band All-sky Monitor (WAM), which covers the energy range 50-5000 keV. For most bursts in this sample we can precisely determine E(sub peak) and for bursts with known redshift we can compare how the E(sub peak) relations for the Swift/Suzaku sample compare to earlier published results. Keywords: gamma rays: burst
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