Expansion Velocity of Ejecta in Tycho's Supernova Remnant Measured by Doppler Broadened X-ray Line Emission

We show that the expansion of ejecta in Tycho's supernova remnant (SNR) is consistent with a spherically symmetric shell, based on Suzaku measurements of the Doppler broadened X-ray emission lines. All the strong K_alpha line emission show broader widths at the center than at the rim, while the centroid energies are constant across the remnant (except for Ca). This is the pattern expected for Doppler broadening due to expansion of the SNR ejecta in a spherical shell. To determine the expansion velocities of the ejecta, we applied a model for each emission line feature having two Gaussian components separately representing red- and blue-shifted gas, and inferred the Doppler velocity difference between these two components directly from the fitted centroid energy difference. Taking into account the effect of projecting a three-dimensional shell to the plane of the detector, we derived average spherical expansion velocities independently for the K_alpha emission of Si, S, Ar, and Fe, and K_beta of Si. We found that the expansion velocities of Si, S, and Ar ejecta of 4700+/-100 km/s are distinctly higher than that obtained from Fe K_alpha emission, 4000+/-300 km/s, which is consistent with segregation of the Fe in the inner ejecta. Combining the observed ejecta velocities with the ejecta proper-motion measurements by Chandra, we derived a distance to the Tycho's SNR of 4+/-1 kpc.Comment: Accepted to Apj, 25 pages, 7 figures, 5 table

Measurement of a small atmospheric νμ/νe\nu_\mu/\nu_e ratio

From an exposure of 25.5~kiloton-years of the Super-Kamiokande detector, 900 muon-like and 983 electron-like single-ring atmospheric neutrino interactions were detected with momentum $p_e > 100$ MeV/$c$, $p_\mu > 200$ MeV/$c$, and with visible energy less than 1.33 GeV. Using a detailed Monte Carlo simulation, the ratio $(\mu/e)_{DATA}/(\mu/e)_{MC}$ was measured to be $0.61 \pm 0.03(stat.) \pm 0.05(sys.)$, consistent with previous results from the Kamiokande, IMB and Soudan-2 experiments, and smaller than expected from theoretical models of atmospheric neutrino production.Comment: 14 pages with 5 figure

重傷外傷の認識が遅れ救急外来で緊急開腹術を行った１例

An８１-year-old man fell down and bruised his left abdomen. After a while the back pain got worse, and he admitted to the Emergency Department. At hospitals admission, several signs of shock were observed, and contrast-enhanced CT revealed a splenic injury. However, it took an hour and a half to diagnose and convene the trauma team because of the lack of information shared among medical staffs and the delay of the recognition as a severe traumatic injury. Since there was no available operation room at the time, nor there wasn’t time to transfer to another hospital, he was forced to undergo emergency open splenectomy at the Emergency Department. That decision saved his life as a result. In ２００２, it revealed that the deaths of about ４０％ of expired trauma patients who arrived at emergency centers were probably preventable. Since then, much progress has been made in establishing and generalizing the trauma care and evaluation guidelines. Our hospital is also making progress in organizing a trauma team and the massive transfusion protocol. However, even if they are well maintained, we won’t be able to decrease the number of preventable trauma deaths（PTD）unless we diagnose it. Improving clinical management as well as making efforts on teamwork, leads to a rapid definitive care in trauma patients

Mechanism of castration-resistant acquisition via 3-O-sulfated heparan sulfate in prostate cancer

創価大学博士（工学）Androgen deprivation therapy is commonly administered to suppress the growth of prostate cancer. However, despite this treatment, certain cells continue growing independently of hormones, leading to the development of castration-resistant prostate cancer (CRPC). Prostate cancer proliferates through androgen receptor (AR) signaling. However, in the case of CRPC, signaling pathways other than AR signaling are involved in the proliferation. Sulfated glycosaminoglycans function as co-receptors to promote ligand binding to receptors in signaling pathway, but their specific role in CRPC has remained unclear. In this study, we used the human prostate cancer cell line C4-2, which can proliferate under both hormone-dependent and hormone-independent conditions, as CRPC model. We have found that when hormones were depleted, epidermal growth factor (EGF) triggers the activation of EGFR-ERK1/2 signaling through 3-O-sulfated heparan sulfate (3-OS HS) in C4-2 cells. By suppressing the expression of HS3ST1 in C4-2 cells, we were able to inhibit the activation of EGFR-ERK1/2 signaling and hormone-independent growth. Furthermore, treatment with gefitinib, an EGFR inhibitor, significantly suppressed the growth of xenografted C4-2 tumors in castrated mice. In summary, our study has revealed a mechanism of castration-resistant acquisition via 3-OS HS in prostate cancer. These findings contribute to our understanding of CRPC and pave the way for potential therapeutic approaches targeting this mechanism.doctoral thesi

Multilevel Storage in N-Doped Sb 2 Te 3 -Based Lateral Phase Change Memory with an Additional Top TiN Layer

In this study, we present the physical images of multilevel storage (MLS) in both vertical and lateral phase change memory (PCM) devices and investigate MLS in a lateral PCM device with an additional top heater (LTH-PCM). The active layers above two lateral electrodes consist of a 50-nm-thick TiN layer as a top heater and a 150-nm-thick N-doped Sb 2 Te 3 layer. A number of distinct intermediate levels are obtained by current sweeping or pulse application. According to our analysis, MLS in our devices results mainly from the gradual crystallization between electrodes by Joule heating.

Highly sulfated hyaluronic acid maintains human induced pluripotent stem cells under feeder-free and bFGF-free conditions

Human induced pluripotent stem (hiPS) cells are attracting attention as a tool for regenerative medicine. However, several problems need to be overcome for their widespread and safe use, for example, the high cost of maintaining hiPS cells and the possibility of xenogeneic cell contamination in hiPS cell cultures. One of the main contributors to the high cost of maintaining hiPS cells is basic fibroblast growth factor (bFGF), which is essential for such cultures. Xenogeneic contamination can occur because of the use of mouse-derived feeder cells to culture hiPS cells. To overcome the problems of cell culture cost and xenogeneic contamination, we have developed a novel culture method in which the undifferentiated state and pluripotency of hiPS cells can be maintained under feeder-free and bFGF-free conditions. Our new approach involves the addition to the culture medium of highly sulfated hyaluronic acid (HA-HS), in which the hydroxyl groups of d-glucuronic acid (GlcA) and N-acetyl-d-glucosamine (GlcNAc) are chemically sulfated. HA-HS promotes bFGF signaling and maintains the undifferentiated state and pluripotency of hiPS cells under feeder-free and bFGF-free conditions. By contrast, non-sulfated hyaluronic acid and low sulfated hyaluronic acid do not maintain the undifferentiated state and pluripotency of hiPS cells. These results indicate that the maintenance of hiPS cells under feeder-free and bFGF-free conditions is an HA-HS specific effect. This study is the first to demonstrate the effects of sulfated hyaluronic acid on mammalian pluripotent stem cells, and provides a novel method for maintaining hiPS cells using HA-HS