Nucleosynthesis in novae: experimental progress in the determination of nuclear reaction rates

The sources of nuclear uncertainties in nova nucleosynthesis have been identified using hydrodynamical nova models. Experimental efforts have followed and significantly reduced those uncertainties. This is important for the evaluation of nova contribution to galactic chemical evolution, gamma--ray astronomy and possibly presolar grain studies. In particular, estimations of expected gamma-ray fluxes are essential for the planning of observations with existing or future satellites.Comment: Invited contribution to the "Origin of Matter and Evolution of Galaxies" conference (OMEG07) with additional and color figure

Stress responsive miR-23a attenuates skeletal muscle atrophy by targeting MAFbx /atrogin-1

Muscle atrophy occurs in many pathological states and results primarily from accelerated protein degradation by the ubiquitin-proteasome pathway. We used dexamethasone to induce muscle wasting and investigated the role of a microRNA (miRNA) in the control of muscle-specific E3 ubiquitin ligase MAFbx/atrogin-1. Here we show that miR-23a suppresses MAFbx/atrogin-1 translation by binding to 3'UTR of the mRNA. Furthermore, ectopic expression of miR-23a is sufficient to protect myocytes from atrophy in vitro and in vivo in response to dexamethasone treatment, and heat stress-induced miR-23a protects muscle from dexamethasone-induced muscle atrophy. Our surprising discovery of the physiological role of miR-23a in preventing the atrophy program should lay the basis not only for further understanding of the mechanisms of muscle wasting in diverse diseases, but also for developing novel therapies for these debilitating conditions

Explosions inside Ejecta and Most Luminous Supernovae

The extremely luminous supernova SN2006gy is explained in the same way as other SNIIn events: light is produced by a radiative shock propagating in a dense circumstellar envelope formed by a previous weak explosion. The problems in the theory and observations of multiple-explosion SNe IIn are briefly reviewed.Comment: 9 pages, 6 figures, LateX aipproc.cls. A bit more details and color added to Fig.3. The 10th International Symposium on Origin of Matter and Evolution of Galaxies (OMEG07), Sapporo, Japan, December 200

Fluorescence diagnosis of metastatic lymph nodes using 5-aminolevulinic acid (5-ALA) in a mouse model of colon cancer.

[Background]Lymph node metastasis is one of the most critical prognostic factors in patients with colorectal cancer. Although regional lymph nodes should be surgically resected and pathologically examined, techniques for the intraoperative diagnosis of lymph node metastasis remain to be well established. Fluorescence diagnosis using 5-aminolevulinic acid (5-ALA) is a promising technique for evaluating various malignancies. After exogenous administration of 5-ALA, protoporphyrin IX (PPIX) accumulates in malignant cells and can be detected as red fluorescence. In this study, we investigated the usefulness of fluorescence diagnosis using 5-ALA for the detection of lymph node metastasis in a mouse model of colon cancer. [Materials and Methods]An orthotopic colon cancer model was prepared by inoculating the cecal wall of nude mice with HCA7, a human colon adenocarcinoma cell line. After 3 wk, 40 mg/kg of 5-ALA was administered intraperitoneally (IP) or orally (PO). Fluorescence diagnosis with a D-Light System (Karl Storz) was then performed after 3 or 6 h. [Results]In the IP group, PPIX fluorescence was detected in metastatic lymph nodes as well as in other malignant lesions, including primary tumors and abdominal implantations, while non-metastatic nodes were fluorescence-negative. In contrast, no obvious fluorescence was detected in cancerous tissues in the PO group. [Conclusions]PPIX fluorescence induced by intraperitoneal injection of 5-ALA allows metastatic lymph nodes to be accurately diagnosed in this mouse model. This technique may facilitate the intraoperative diagnosis of lymph node metastases from colon cancer in a clinical setting

Recent Efforts in Data Compilations for Nuclear Astrophysics

Some recent efforts in compiling data for astrophysical purposes are introduced, which were discussed during a JINA-CARINA Collaboration meeting on "Nuclear Physics Data Compilation for Nucleosynthesis Modeling" held at the ECT* in Trento/ Italy from May 29th- June 3rd, 2007. The main goal of this collaboration is to develop an updated and unified nuclear reaction database for modeling a wide variety of stellar nucleosynthesis scenarios. Presently a large number of different reaction libraries (REACLIB) are used by the astrophysics community. The "JINA Reaclib Database" on http://www.nscl.msu.edu/\~nero/db/ aims to merge and fit the latest experimental stellar cross sections and reaction rate data of various compilations, e.g. NACRE and its extension for Big Bang nucleosynthesis, Caughlan and Fowler, Iliadis et al., and KADoNiS. The KADoNiS (Karlsruhe Astrophysical Database of Nucleosynthesis in Stars, http://nuclear-astrophysics.fzk.de/kadonis) project is an online database for neutron capture cross sections relevant to the s process. The present version v0.2 is already included in a REACLIB file from Basel university (http://download.nucastro.org/astro/reaclib). The present status of experimental stellar $(n,\gamma)$ cross sections in KADoNiS is shown. A "high priority list" for measurements and evaluations for light charged-particle reactions set up by the JINA-CARINA collaboration is presented. The central web access point to submit and evaluate new data is provided by the Oak Ridge group via the http://www.nucastrodata.org homepage. "Workflow tools" aim to make the evaluation process transparent and allow users to follow the progress.Comment: Proceedings 10th Int. Symp. on Origin of Matter and Evolution of Galaxies OMEG07, Sapporo/ Japan, December 4-7 200

Properties of OV Spectral Lines in Ionizing and Recombining Plasmas

A collisional-radiative model for Be-like oxygen ions has been constructed for OV plasmaspectroscopy. The model takes into account recombination processes as well as collisional ionization, radiative transitions, and collisional excitation/deexcitation. Two sets of atomic data are used for comparison. We obtain OV line intensities as functions of electron temperature and density. The line intensity ratios of 2s3s 35 - 2s3p \u27Pr=o.r., are measured in LHD plasmas and are consistent with our models. The line intensity ratio of 2s2p 3P - 2p"P and 2s2 tS - 2s2p rP in recombining plasma is an increasing function of temperature and one measured in the LHD plasma indicates electron temperature less than 7eV. The ratios measured in steady-state phase are larger than I and difficult to explain with the current model

The Long-term Corrosion Behaviour of Abandoned Wells Under CO2 Geological Storage Conditions: (2) Experimental Results for Corrosion of Casing Steel

AbstractRegarding the geological storage of CO2 in aquifers or in depleted gas fields, the reactivity of the well casing left in the abandoned well is important in order to investigate the potential for leakage. The corrosion behavior of the casing steel tube was investigated in highly pressurized CO2 environments.The corrosion test of the J55 and N80 steel tube in API specification 5CT was conducted. Those steel tubes have been frequently used as casing tube and are found in abandoned natural gas wells. The following test conditions were achieved with the autoclave apparatus: temperature at 50 to 70°C, CO2 pressure at 5 to 18MPa with/without the impurities of 20ppm H2S and 2000ppm CO, in/above stagnant 0.5M NaCl solution of simulated formation water. The test durations were 100, 300 and 1000hours.After the corrosion test, the specimens were analyzed by Energy dispersive X-ray spectrometry and X-ray diffractometry. The specimens were found to be covered mainly with FeCO3, which is considered to be formed from dissolved Fe2+ and environmental CO2. The corrosion rate was evaluated via the weight loss of the specimens after the removal of the surface corrosion products, containing FeCO3. No significant differences were observed between J55 and N80 in terms of FeCO3 formation and corrosion weight loss. It was found that the weight loss by corrosion, around 100mg/cm2 after 100hours, was remarkably large when the specimen was placed in the solution and was, in contrast, two orders of magnitude smaller when the specimen was above the solution. In the case with the impurities of 20ppm H2S and 2000ppm CO, the weight loss in the solution was less relative to the pure CO2 condition. The weight loss in the solution reached a plateau in initial 100hours, and was only slightly increased in the 300- and the 1000-hour tests. The ‘plateau’ was considered to be due to the protective effect of the FeCO3 formed on the specimen. Considering the protective effect of the FeCO3, the corrosion of the steel casing over a long period of time is small under the stagnant condition, and would be expected to remain in place with little structural degradation

The Dichotomy of the Halo of the Milky Way

We summarize evidence that the halo of the Milky Way comprises two different, and broadly overlapping, stellar components. The two structures exhibit different chemical compositions, spatial distributions, and kinematics. These results were obtained through an analysis of more than 20,000 calibration stars from the Sloan Digital Sky Survey (SDSS). The duality of the stellar halo directly impacts galaxy formation models, for the Milky Way and other large spirals.Comment: 6 pages, 4 figures, to appear in Proceedings of the OMEG07 Conference, held in December 200