102 research outputs found

    Evolution of Supernova Remnants Expanding out of the Dense Circumstellar Matter into the Rarefied Interstellar Medium

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    We carry out 3D-hydrodynamical calculations for the interaction of expanding supernova ejecta with the dense circumstellar matter (CSM) and the rarefied interstellar medium (ISM) outside. The CSM is composed of the stellar wind matter from the progenitor in its pre-supernova phase, and assumed to be axially symmetric: more matter around the equator than in the polar direction driven by rotation of the progenitor. Because of high density of the CSM, the ionization state of the shock-heated ejecta quickly becomes equilibrium with the electron temperature. When the blast wave breaks out of the CSM into the rarefied ISM, the shocked ejecta cools rapidly due to adiabatic expansion, and hence an over-ionized/recombining plasma would be left. The ejecta is reheated by the second reverse shock due to the interaction with the ISM. We calculate the emission measure of the supernova remnant (SNR) along the line of sight, and find that the over-ionized plasma appears to be bar-like with wings in the edge-on (equatorial view), while shell-like in the face-on (polar view) geometry with respect to the rotation axis. The hot gas heated by the blast wave exists in the outermost region of the SNR with a nearly complete shell, but the X-rays therefrom are too faint to be observable. Thus, depending on the viewing angle, the SNR of the over-ionized plasma would exhibit center-filled morphology in X-rays, like W49B, a mixed-morphology SNR. The bar-like structure is swept out by the second reverse shock and disappears eventually, and then the SNR becomes shell-like in both the equatorial and polar views in the later phase of the evolution.Comment: 8 pages, 9 figures, accepted for publication in PAS

    Impact of Hepatitis Virus on the Feasibility and Efficacy of Anticancer Agents in Patients With Hepatocellular Carcinoma in Phase I Clinical Trials

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    Chronic viral hepatitis is a risk factor for liver fibrosis and hepatocellular carcinoma (HCC). Patients with advanced HCC have limited effective therapeutic options and are considered potential candidates for early phase clinical trials of anti-cancer agents. The impact of chronic viral hepatitis on the efficacy of anticancer agents for patients with HCC in phase I trials (P-Is) still remains unclear and has not been reported. We retrospectively analyzed the outcomes of consecutive HCC patients in P-Is conducted in a single institute, focusing on chronic viral hepatitis. Of 85 patients enrolled in P-Is, 46 (54%) patients positive and 39 (46%) patients negative for chronic viral hepatitis showed no significant difference in clinical and laboratory variables and on the point of the best response based on the Response Evaluation Criteria in Solid Tumors (RECIST) criteria; moreover, the frequency of Grade ≄3 adverse events (AE) was not significantly different. The median time to treatment failure (TTF) and overall survival (OS) from the P-I enrolment were 2.0 and 13.7 months, respectively. No patient experienced reactivation of hepatitis B virus (HBV) or treatment-related death. Chronic viral hepatitis does not independently affect the outcomes of anticancer drugs. Advanced HCC patients with chronic viral hepatitis could be feasible for P-Is

    Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network

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    Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects

    Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

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    Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≀0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

    Ultralight vector dark matter search using data from the KAGRA O3GK run

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    Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

    Flow Boiling Heat Transfer and Pressure Drop of R1234ze(E) and R32 in a Horizontal Micro-Fin Tube

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    In the present study, the flow boiling heat transfer of R1234ze(E), R32 and zeotropic mixture R1234ze(E)/R32 (50/50 mass%) in a horizontal micro-fin tube is experimentally investigated to clarify the pressure drop and heat transfer characteristics. Tested micro-fin tube is made of copper, and its geometry is as follows, 6.00 mm in outer diameter, 5.21 mm in mean inside diameter, 0.26 mm in fin height and 20 degree in spiral angle. Experiments are conducted in the mass velocity range of 150 to 400 kg m-2s-1 at a constant inlet temperature 10 oC. The effects of mass velocity and the difference of refrigerants on heat transfer and frictional pressure drop characteristics are clarified. The measured pressure drop and heat transfer characteristics of pure refrigerants are also compared with some correlations

    Fabrication of oriented hydroxyapatite film by RF magnetron sputtering

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    Hydroxyapatite (HAp) is compatible with bone tissue and is used mainly as a bone prosthetic material, especially as the coating of implants. Oriented HAp film is expected to be a high-quality epitaxial scaffold of the neonatal bone. To fabricate highly oriented HAp thin films via the conventional plasma process, we deposited the HAp film on a Ti coated silica glass substrate using RF magnetron sputtering in low substrate temperature conditions. The X-ray diffraction pattern of the film sample consisted of an intense (002) peak, corresponding to the highly oriented HAp. The (002) peak in XRD diagrams can be attributed either to the monoclinic phase or the hexagonal phase. Pole figure analysis showed that the (002) plane grew parallel to the surface of the substrate, without inclination. Transmission Electron Microscope analysis also showed the fabrication of aligned HAp crystallites. The selected area diffraction patterns indicated the existence of monoclinic phase. The existence of hexagonal phase could not be judged. These results indicate the uniaxial films fabricated by this technique enable to be the epitaxial scaffold of the neonatal bone. This scaffold can be expected to promote connection with the surrounding bone tissue and recovery of the dynamic characteristics of the bone
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