Iron Emission Lines on the Galactic Ridge Observed with Suzaku

In order to elucidate origin of the Galactic Ridge X-ray Emission, we analyzed Suzaku data taken at various regions along the Galactic plane and studied their Fe-K emission line features. Suzaku resolved the Fe line complex into three narrow lines at ~6.4 keV,~6.7 keV and ~6.97 keV, which are K-lines from neutral (or low-ionized), He-like, and H-like iron ions, respectively. The 6.7 keV line is clearly seen in all the observed regions and its longitudinal distribution is consistent with that determined from previous observations. The 6.4 keV emission line was also found in various Galactic plane regions (b~0). Differences in flux ratios of the 6.4 keV/6.7 keV and 6.97 keV/6.7 keV lines between the Galactic plane and the Galactic center regions are studied and its implication is discussed.Comment: Accepted for publication in PASJ Suzaku 3rd special issu

Formation of a Massive Black Hole at the Center of the Superbubble in M82

We performed 12CO(1-0), 13CO(1-0), and HCN(1-0) interferometric observations of the central region (about 450 pc in radius) of M82 with the Nobeyama Millimeter Array, and have successfully imaged a molecular superbubble and spurs. The center of the superbubble is clearly shifted from the nucleus by 140 pc. This position is close to that of the massive black hole (BH) of >460 Mo and the 2.2 micron secondary peak (a luminous supergiant dominated cluster), which strongly suggests that these objects may be related to the formation of the superbubble. Consideration of star formation in the cluster based on the infrared data indicates that (1) energy release from supernovae can account for the kinetic energy of the superbubble, (2) the total mass of stellar-mass BHs available for building-up the massive BH may be much higher than 460 Mo, and (3) it is possible to form the middle-mass BH of 100-1000 Mo within the timescale of the superbubble. We suggest that the massive BH was produced and is growing in the intense starburst region.Comment: 9 pages, 3 figures, to appear in ApJ Lette

X-ray Spectral Study of the extended emission,'the Cap', located 11.6 kpc above the disk of M82

The extended X-ray emission from 'the Cap' region located 11' (11.6 kpc) above the disk of the starburst galaxy M82 has been observed with Suzaku and XMM-Newton. Owing to the good energy resolution and the large collecting area of the XIS on Suzaku, combined with similar properties of the EPIC instrument on XMM-Newton, we have clearly detected K-shell emission lines from O VII, O VIII, Ne X, Mg XI, Mg XII and the Fe-L complex. Two optically-thin thermal plasma components are required to fit the observed X-ray spectra. We have determined the metal abundances of O, Ne, Mg, Si and Fe in this region for the first time. Their metal abundance ratios agree well with those of metal-poor stars and the model prediction of metals synthesized by type-II supernovae, but they are not consistent with the metallicities of type-Ia supernovae. This result is support for the idea that the origin of the metals in the Cap is type-II supernovae explosions occurring in the starburst regions in the M82 galaxy. We discuss the possible contribution from sputtered dust grains to the metals in the Cap. An emission line consistent with the C VI transition of n=4 to 1 at 0.459 keV is marginally detected, although it is not statistically significant at the 99% confidence level; the presence of this line would suggest charge-exchange processes in the Cap.Comment: 16 pages, 10 figuer

Cryo-EM structure of a helicase loading intermediate containing ORC-Cdc6-Cdt1-MCM2-7 bound to DNA

In eukaryotes, the Cdt1-bound replicative helicase core MCM2-7 is loaded onto DNA by the ORC-Cdc6 ATPase to form a prereplicative complex (pre-RC) with an MCM2-7 double hexamer encircling DNA. Using purified components in the presence of ATP-γS, we have captured in vitro an intermediate in pre-RC assembly that contains a complex between the ORC-Cdc6 and Cdt1-MCM2-7 heteroheptamers called the OCCM. Cryo-EM studies of this 14-subunit complex reveal that the two separate heptameric complexes are engaged extensively, with the ORC-Cdc6 N-terminal AAA+ domains latching onto the C-terminal AAA+ motor domains of the MCM2-7 hexamer. The conformation of ORC-Cdc6 undergoes a concerted change into a right-handed spiral with helical symmetry that is identical to that of the DNA double helix. The resulting ORC-Cdc6 helicase loader shows a notable structural similarity to the replication factor C clamp loader, suggesting a conserved mechanism of action

How should tracers be injected to detect for sentinel nodes in gastric cancer – submucosally from inside or subserosally from outside of the stomach?

<p>Abstract</p> <p>Background</p> <p>In sentinel node (SN) detection for cases of early gastric cancer, the submucosal dye injection method appears to be more reasonable than the subserosal injection. To compare the two injection methods, we have focused on the rate of concordance between hot nodes (HNs) obtained from the radioisotope (RI) method and green nodes (GNs) obtained from the dye-guided method in addition to the number and distribution of GNs detected, and the sensitivity of metastatic detection.</p> <p>Methods</p> <p>The subjects of this study were 63 consecutive patients with gastric cancer (sT1–T2, sN0, tumor diameter ≦ 4 cm) in whom we attempted SN detection using a combination of RI and dye methods. ^99mTc-tin colloid was injected a day before the surgery, and indocyanine green was injected either submucosally (n = 43) with endoscopes or subserosally (n = 20) by direct vision.</p> <p>Results</p> <p>An average of hot and green nodes (H&G: 4 ± 3 vs. 4 ± 3), hot and non-green nodes (H&NG: 2 ± 3 vs. 1 ± 2), cold and green nodes (C&G: 2 ± 2 vs. 3 ± 4), and the rate of concordance (H&G/H&G + H&NG + C&G: 45 + 27% vs. 48 ± 30%) were not significantly different between the submucosal and subserosal injection methods. The spread of GNs to tier 2 stations (24% vs. 30%) and metastatic detection sensitivity (86% vs. 100%) were also not different between the submucosal and subserosal injection methods.</p> <p>Conclusion</p> <p>The tracer injection sites do not have to be limited to the submucosa.</p

The development and growth of tissues derived from cranial neural crest and primitive mesoderm is dependent on the ligation status of retinoic acid receptor γ:evidence that retinoic acid receptor γ functions to maintain stem/progenitor cells in the absence of retinoic acid

Retinoic acid (RA) signaling is important to normal development. However, the function of the different RA receptors (RARs)-RARα, RARβ, and RARγ-is as yet unclear. We have used wild-type and transgenic zebrafish to examine the role of RARγ. Treatment of zebrafish embryos with an RARγ-specific agonist reduced somite formation and axial length, which was associated with a loss of hoxb13a expression and less-clear alterations in hoxc11a or myoD expression. Treatment with the RARγ agonist also disrupted formation of tissues arising from cranial neural crest, including cranial bones and anterior neural ganglia. There was a loss of Sox 9-immunopositive neural crest stem/progenitor cells in the same anterior regions. Pectoral fin outgrowth was blocked by RARγ agonist treatment. However, there was no loss of Tbx-5-immunopositive lateral plate mesodermal stem/progenitor cells and the block was reversed by agonist washout or by cotreatment with an RARγ antagonist. Regeneration of the caudal fin was also blocked by RARγ agonist treatment, which was associated with a loss of canonical Wnt signaling. This regenerative response was restored by agonist washout or cotreatment with the RARγ antagonist. These findings suggest that RARγ plays an essential role in maintaining stem/progenitor cells during embryonic development and tissue regeneration when the receptor is in its nonligated state

Atypical disengagement from faces and its modulation by the control of eye fixation in children with Autism Spectrum Disorder

By using the gap overlap task, we investigated disengagement from faces and objects in children (9–17 years old) with and without autism spectrum disorder (ASD) and its neurophysiological correlates. In typically developing (TD) children, faces elicited larger gap effect, an index of attentional engagement, and larger saccade-related event-related potentials (ERPs), compared to objects. In children with ASD, by contrast, neither gap effect nor ERPs differ between faces and objects. Follow-up experiments demonstrated that instructed fixation on the eyes induces larger gap effect for faces in children with ASD, whereas instructed fixation on the mouth can disrupt larger gap effect in TD children. These results suggest a critical role of eye fixation on attentional engagement to faces in both groups

Starburst at the Expanding Molecular Superbubble in M82: Self-Induced Starburst at the Inner Edge of the Superbubble

We present high spatial resolution (2.3"x1.9" or 43 pc x 36 pc at D = 3.9 Mpc) 100 GHz millimeter-wave continuum emission observations with the Nobeyama Millimeter Array toward an expanding molecular superbubble in the central region of M82. The 100 GHz continuum image, which is dominated by free-free emission, revealed that the four strongest peaks are concentrated at the inner edge of the superbubble along the galactic disk. The production rates of Lyman continuum photons calculated from 100 GHz continuum flux at these peaks are an order of magnitude higher than those from the most massive star forming regions in our Galaxy. At these regions, high velocity ionized gas (traced by H41a and [Ne II]) can be seen, and H2O and OH masers are also concentrated. The center of the superbubble, on the other hand, is weak in molecular and free-free emissions and strong in diffuse hard X-ray emission. These observations suggest that a strong starburst produced energetic explosions and resultant plasma and superbubble expansions, and induced the present starburst regions traced by our 100 GHz continuum observations at the inner edge of the molecular superbubble. These results, therefore, provide the first clear evidence of self-induced starburst in external galaxies. Starburst at the center of the superbubble, on the other hand, begins to cease because of a lack of molecular gas. This kind of intense starburst seems to have occurred several times within 10^6-10^7 years in the central region of M82.Comment: 30 pages, 6 figures. To be appeared in ApJ, 617, 20 December 2004 issu

A role of 18F-fluorodeoxyglucose positron emission/computed tomography in a strategy for abdominal wall metastasis of colorectal mucinous adenocarcinoma developed after laparoscopic surgery

Metastasis to the abdominal wall including port sites after laparoscopic surgery for colorectal cancer is rare. Resection of metastatic lesions may lead to greater survival benefit if the abdominal wall metastasis is the only manifestation of recurrent disease. A 57-year-old man, who underwent laparoscopic surgery for advanced mucinous adenocarcinoma of the cecum 6 years prior, developed a nodule in the surgical wound at the lower right abdomen. Although tumor markers were within normal limits, the metastasis to the abdominal wall and abdominal cavity from the previous cecal cancer was suspected. An abdominal computed tomography scan did not provide detective evidence of metastasis. 18F-fluorodeoxyglucose positron emission/computed tomography (18F-FDG PET/CT) was therefore performed, which demonstrated increased 18F-fluorodeoxyglucose uptake (maximum standardized uptake value: 3.1) in the small abdominal wall nodule alone. Histopathological examination of the resected nodule confirmed the diagnosis of metastatic mucinous adenocarcinoma. Prognosis of intestinal mucinous adenocarcinoma is reported to be poorer than that of non-mucinous adenocarcinoma. In conclusion, this case suggests an important role of 18F-FDG PET/CT in early diagnosis and decision-making regarding therapy for recurrent disease in cases where a firm diagnosis of recurrent colorectal cancer is difficult to make