Hard X-Ray Spectrum from West Lobe of Radio Galaxy Fornax A Observed with Suzaku

An observation of the West lobe of radio galaxy Fornax A (NGC 1316) with Suzaku is reported. Since Feigelson et al. (1995) and Kaneda et al. (1995) discovered the cosmic microwave background boosted inverse-Comptonized (IC) X-rays from the radio lobe, the magnetic field and electron energy density in the lobes have been estimated under the assumption that a single component of the relativistic electrons generates both the IC X-rays and the synchrotron radio emission. However, electrons generating the observed IC X-rays in the 1 -- 10 keV band do not possess sufficient energy to radiate the observed synchrotron radio emission under the estimated magnetic field of a few micro-G. On the basis of observations made with Suzaku, we show in the present paper that a 0.7 -- 20 keV spectrum is well described by a single power-law model with an energy index of 0.68 and a flux density of 0.12+/-0.01 micro-Jy at 1 keV from the West lobe. The derived multiwavelength spectrum strongly suggests that a single electron energy distribution over a Lorentz factor gamma = 300 - 90000 is responsible for generating both the X-ray and radio emissions. The derived physical quantities are not only consistent with those reported for the West lobe, but are also in very good agreement with those reported for the East lobe.Comment: 8 pages, 6 figures; accepted for publication in PASJ (Publications of the Astronomical Society of Japan) Suzaku 3rd special issue: TYPOS in flux density unit were correcte

Suzaku diagnostics of the energetics in the lobes of the giant radio galaxy 3C 35

The Suzaku observation of a giant radio galaxy 3C 35 revealed faint extended X-ray emission, associated with its radio lobes and/or host galaxy. After careful subtraction of the X-ray and non-X-ray background and contaminating X-ray sources, the X-ray spectrum of the faint emission was reproduced by a sum of the power-law (PL) and soft thermal components. The soft component was attributed to the thermal plasma emission from the host galaxy. The photon index of the PL component, $\Gamma = 1.35_{-0.86}^{+0.56}$$_{-0.10}^{+0.11}$ where the first and second errors represent the statistical and systematic ones, was found to agree with the synchrotron radio index from the lobes, $\Gamma_{\rm R} = 1.7$. Thus, the PL component was attributed to the inverse Compton (IC) X-rays from the synchrotron electrons in the lobes. The X-ray flux density at 1 keV was derived as $13.6\pm 5.4_{-3.6}^{+4.0}$ nJy with the photon index fixed at the radio value. The X-ray surface brightness from these lobes ($\sim 0.2$ nJy arcmin$^{-2}$) is lowest among the lobes studied through the IC X-ray emission. In combination with the synchrotron radio flux density, $7.5 \pm 0.2$ Jy at 327.4 MHz, the electron energy density spatially averaged over the lobes was evaluated to be the lowest among those radio galaxies, as $u_{\rm e} = (5.8 \pm 2.3 _{-1.7}^{+1.9}) \times 10^{-14}$ ergs cm$^{-3}$ over the electron Lorentz factor of $10^{3}$ -- $10^{5}$. The magnetic energy density was calculated as $u_{\rm m}=(3.1_{-1.0}^{+2.5}$$_{-0.9}^{+1.4}) \times 10^{-14}$ ergs cm$^{-3}$, corresponding to the magnetic field strength of $0.88_{-0.16}^{+0.31}$$_{-0.14}^{+0.19}$ $\mu$G. These results suggest that the energetics in the 3C 35 lobes are nearly consistent with equipartition between the electrons and magnetic fields.Comment: 10 pages, 8 figures, accepted for Ap

Suzaku observation of the giant radio galaxy 3C 326

A Suzaku observation of a giant radio galaxy, 3C 326, which has a physical size of about 2 Mpc, was conducted on 2008 January 19 -- 21. In addition to several X-ray sources, diffuse emission was significantly detected associated with its west lobe, but the east lobe was contaminated by an unidentified X-ray source WARP J1552.4+2007. After careful evaluation of the X-ray and Non X-ray background, the 0.4 -- 7 keV X-ray spectrum of the west lobe is described by a power-law model. The photon index and 1 keV flux density was derived as $1.82_{-0.24}^{+0.26}\pm0.04$ and $19.4_{-3.2}^{+3.3}\pm 3.0$ nJy, respectively, where the first and second errors represent the statistical and systematic ones. The diffuse X-rays were attributed to be inverse Compton radiation by the synchrotron radio electrons scattering off the cosmic microwave background photons. This radio galaxy is the largest among those with lobes detected through inverse Compton X-ray emission. A comparison of the radio to X-ray fluxes yields the energy densities of electron and magnetic field as $u_e = (2.3 \pm 0.3 \pm 0.3) \times 10^{-13}$ ergs/cm3 and $u_m = (1.2_{-0.1}^{+0.2}\pm 0.2) \times 10^{-14}$ ergs/cm3, respectively. The galaxy is suggested to host a low luminosity nucleus with an absorption-corrected 2 -- 10 keV luminosity of $<2 \times 10^{42}$ ergs/s, together with a relatively weak radio core. The energetics in the west lobe of 3C 326 were compared with those of moderate radio galaxies with a size of $\sim 100$ kpc. The west lobe of 3C 326 is confirmed to agree with the correlations for the moderate radio galaxies, $u_e \propto D^{-2.2\pm0.4}$ and $u_m \propto D^{-2.4\pm0.4}$, where $D$ is their total physical size. This implies that the lobes of 3C 326 are still being energized by the jet, despite the current weakness of the nucleus.Comment: 11 pages, 10 figures, 6 tables, Accepted for ApJ (v706 issue

ALMA ACA detection of submillimeter emission associated with the west hot spot of the radio galaxy Pictor A

In order to investigate the far-infrared excess detected from the west hot spot of the radio galaxy Pictor A with the Herschel observatory, a submillimeter photometry is performed with the Atacama Compact Array (ACA) of the Atacama Large Millimeter/submillimeter Array at Band 8 with the reference frequency of 405 GHz. A submillimeter source is discovered at the radio peak of the hot spot. Because the 405 GHz flux density of the source, $80.7\pm3.1$ mJy, agrees with the extrapolation of the synchrotron radio spectrum, the far-infrared excess is suggested to exhibit no major contribution at the ACA band. In contrast, by subtracting the power-law spectrum tightly constrained by the radio and ACA data, the significance of the excess in the Herschel band is well confirmed. No diffuse submillimeter emission is detected within the ACA field of view, and thus, the excess is ascribed to the west hot spot itself. In comparison to the previous estimate based on the Herschel data, the relative contribution of the far-infrared excess is reduced by a factor of $\sim 1.5$. The spectrum of the excess below the far-infrared band is determined to be harder than that of the diffusive shock acceleration. This strengthens the previous interpretation that the excess originates via the magnetic turbulence in the substructures within the hot spot. The ACA data are utilized to evaluate the magnetic field strength of the excess and of diffuse radio structure associated to the hot spot.Comment: 10 pages,4 figures, 3 tables, accepted for Ap

Surgery for Irradiation Damage to the Digestive Tract.

The surgical outcome of radiation injury to the gut was evaluated on the basis of clinical experience. The main affected gut was the rectum in frequency. In most cases, colostomy was selected and the affected gut was left as it was. Some suffered from bleeding episode and 4 had carcinoma arising from radiation injury. In conclusion, early resection of affected guts associated with clinical symptoms is recommended as the treatment of radiation-injured gut

High-Sensitivity Real-Time Imaging of Dual Protein-Protein Interactions in Living Subjects Using Multicolor Luciferases

Networks of protein-protein interactions play key roles in numerous important biological processes in living subjects. An effective methodology to assess protein-protein interactions in living cells of interest is protein-fragment complement assay (PCA). Particularly the assays using fluorescent proteins are powerful techniques, but they do not directly track interactions because of its irreversibility or the time for chromophore formation. By contrast, PCAs using bioluminescent proteins can overcome these drawbacks. We herein describe an imaging method for real-time analysis of protein-protein interactions using multicolor luciferases with different spectral characteristics. The sensitivity and signal-to-background ratio were improved considerably by developing a carboxy-terminal fragment engineered from a click beetle luciferase. We demonstrate its utility in spatiotemporal characterization of Smad1–Smad4 and Smad2–Smad4 interactions in early developing stages of a single living Xenopus laevis embryo. We also describe the value of this method by application of specific protein-protein interactions in cell cultures and living mice. This technique supports quantitative analyses and imaging of versatile protein-protein interactions with a selective luminescence wavelength in opaque or strongly auto-fluorescent living subjects

A CRAF/glutathione-S-transferase P1 complex sustains autocrine growth of cancers with KRAS and BRAF mutations

The Ras/RAF/MEK/ERK pathway is an essential signaling cascade for various refractory cancers, such as those with mutant KRAS (mKRAS) and BRAF (mBRAF). However, there are unsolved ambiguities underlying mechanisms for this growth signaling thereby creating therapeutic complications. This study shows that a vital component of the pathway CRAF is directly impacted by an end product of the cascade, glutathione transferases (GST) P1 (GSTP1), driving a previously unrecognized autocrine cycle that sustains proliferation of mKRAS and mBRAF cancer cells, independent of oncogenic stimuli. The CRAF interaction with GSTP1 occurs at its N-terminal regulatory domain, CR1 motif, resulting in its stabilization, enhanced dimerization, and augmented catalytic activity. Consistent with the autocrine cycle scheme, silencing GSTP1 brought about significant suppression of proliferation of mKRAS and mBRAF cells in vitro and suppressed tumorigenesis of the xenografted mKRAS tumor in vivo. GSTP1 knockout mice showed significantly impaired carcinogenesis of mKRAS colon cancer. Consequently, hindering the autocrine loop by targeting CRAF/GSTP1 interactions should provide innovative therapeutic modalities for these cancers

Rescue from Stx2-Producing E. coli-Associated Encephalopathy by Intravenous Injection of Muse Cells in NOD-SCID Mice

Shiga toxin-producing Escherichia coli (STEC) causes hemorrhagic colitis, hemolytic uremic syndrome, and acute encephalopathies that may lead to sudden death or severe neurologic sequelae. Current treatments, including immunoglobulin G (IgG) immunoadsorption, plasma exchange, steroid pulse therapy, and the monoclonal antibody eculizumab, have limited effects against the severe neurologic sequelae. Multilineage-differentiating stress-enduring (Muse) cells are endogenous reparative non-tumorigenic stem cells that naturally reside in the body and are currently under clinical trials for regenerative medicine. When administered intravenously, Musecells accumulate to the damaged tissue, where they exert anti-inflammatory, anti-apoptotic, anti-fibrotic, and immunomodulatory effects, and replace damaged cells by differentiating into tissue-constituent cells. Here, severely immunocompromised non-obese diabetic/severe combined immunodeficiency (NOD-SCID) mice orally inoculated with 9 × 109 colony-forming units of STEC O111 and treated 48 h later with intravenous injection of 5 × 104 Muse cells exhibited 100% survival and no severe after-effects of infection. Suppression of granulocyte-colony-stimulating factor (G-CSF) by RNAi abolished the beneficial effects of Muse cells, leading to a 40% death and significant body weight loss, suggesting the involvement of G-CSF in the beneficial effects of Muse cells in STEC-infected mice. Thus, intravenous administration of Muse cells could be a candidate therapeutic approach for preventing fatal encephalopathy after STEC infection