82 research outputs found

    Synergism of Rana catesbeiana ribonuclease and IFN-γ triggers distinct death machineries in different human cancer cells

    Get PDF
    AbstractRana catesbeiana ribonuclease (RC-RNase) possesses tumor-specific cytotoxicity, which can be synergized by IFN-γ. However, it is unclear how RC-RNase and RC-RNase/IFN-γ induce cell death. In this study, we use substrate cleavage assays to systematically investigate RC-RNase- and RC-RNase/IFN-γ-induced caspase activation in HL-60, MCF-7, and SK-Hep-1 cells. We find that RC-RNase and RC-RNase/IFN-γ induce mitochondria-mediated caspase activation in HL-60 and MCF-7 cells but not in SK-Hep-1 cells, although death of SK-Hep-1 cells is closely related to mitochondrial disruptions. Our findings provide evidence that RC-RNase and RC-RNase/IFN-γ can kill different cancer cells by distinct mechanisms. Compared with onconase, RC-RNase seems to harbor a more specific anti-cancer activity

    Data mining tools for Salmonella characterization: application to gel-based fingerprinting analysis

    Get PDF
    BACKGROUND: Pulsed field gel electrophoresis (PFGE) is currently the most widely and routinely used method by the Centers for Disease Control and Prevention (CDC) and state health labs in the United States for Salmonella surveillance and outbreak tracking. Major drawbacks of commercially available PFGE analysis programs have been their difficulty in dealing with large datasets and the limited availability of analysis tools. There exists a need to develop new analytical tools for PFGE data mining in order to make full use of valuable data in large surveillance databases. RESULTS: In this study, a software package was developed consisting of five types of bioinformatics approaches exploring and implementing for the analysis and visualization of PFGE fingerprinting. The approaches include PFGE band standardization, Salmonella serotype prediction, hierarchical cluster analysis, distance matrix analysis and two-way hierarchical cluster analysis. PFGE band standardization makes it possible for cross-group large dataset analysis. The Salmonella serotype prediction approach allows users to predict serotypes of Salmonella isolates based on their PFGE patterns. The hierarchical cluster analysis approach could be used to clarify subtypes and phylogenetic relationships among groups of PFGE patterns. The distance matrix and two-way hierarchical cluster analysis tools allow users to directly visualize the similarities/dissimilarities of any two individual patterns and the inter- and intra-serotype relationships of two or more serotypes, and provide a summary of the overall relationships between user-selected serotypes as well as the distinguishable band markers of these serotypes. The functionalities of these tools were illustrated on PFGE fingerprinting data from PulseNet of CDC. CONCLUSIONS: The bioinformatics approaches included in the software package developed in this study were integrated with the PFGE database to enhance the data mining of PFGE fingerprints. Fast and accurate prediction makes it possible to elucidate Salmonella serotype information before conventional serological methods are pursued. The development of bioinformatics tools to distinguish the PFGE markers and serotype specific patterns will enhance PFGE data retrieval, interpretation and serotype identification and will likely accelerate source tracking to identify the Salmonella isolates implicated in foodborne diseases

    High-Frequency Ultrasound Imaging to Evaluate Liver Fibrosis Progression in Rats and Yi Guan Jian Herbal Therapeutic Effects

    Get PDF
    The animals used in liver fibrosis studies must usually be sacrificed. Ultrasound has been demonstrated to have the ability to diagnose hepatic fibrosis and cirrhosis in experimental small-animal models. However, few studies have used high-frequency ultrasound (HFU, 40 MHz) to monitor changes in the rat liver and other hollow organs longitudinally. In this study, liver fibrosis was induced by administering dimethylnitrosamine (DMN) in SD rats, aged 8 weeks, for three consecutive days per week for up to 4 weeks. A Chinese herbal medicine Yi Guan Jian (YGJ) was orally administered (1.8 g/kg daily) to DMN-induced liver fibrosis rats for 2 weeks. Compared with the normal control rats, rats treated with DMN for either 2 weeks or 4 weeks had significantly lower body weights, liver indexes and elevation of hydroxyproline, GOT, and GPT contents. YGJ herbal treatment remarkably prevented rats from DMN-induced liver fibrosis. The HFU scoring results among the normal controls, 2-week DMN-treated rats, 4-week DMN-treated rats, and combined 2-week YGJ therapy with 4-week DMN-treated rats also reached statistical significance. Thus, HFU is an accurate tool for the longitudinal analysis of liver fibrosis progression in small-animal models, and the YGJ may be useful in reversing the development of hepatic fibrosis

    AMiBA: scaling relations between the integrated Compton-y and X-ray derived temperature, mass, and luminosity

    Full text link
    We investigate the scaling relations between the X-ray and the thermal Sunyaev-Zel'dovich Effect (SZE) properties of clusters of galaxies, using data taken during 2007 by the Y.T. Lee Array for Microwave Background Anisotropy (AMiBA) at 94 GHz for the six clusters A1689, A1995, A2142, A2163, A2261, and A2390. The scaling relations relate the integrated Compton-y parameter Y_{2500} to the X-ray derived gas temperature T_{e}, total mass M_{2500}, and bolometric luminosity L_X within r_{2500}. Our results for the power-law index and normalization are both consistent with the self-similar model and other studies in the literature except for the Y_{2500}-L_X relation, for which a physical explanation is given though further investigation may be still needed. Our results not only provide confidence for the AMiBA project but also support our understanding of galaxy clusters.Comment: Accepted by ApJ; 8 pages, 3 figures, 5 table

    AMiBA: Broadband Heterodyne CMB Interferometry

    Get PDF
    The Y. T. Lee Array for Microwave Background (AMiBA) has reported the first science results on the detection of galaxy clusters via the Sunyaev Zel'dovich effect. The science objectives required small reflectors in order to sample large scale structures (20') while interferometry provided modest resolutions (2'). With these constraints, we designed for the best sensitivity by utilizing the maximum possible continuum bandwidth matched to the atmospheric window at 86-102GHz, with dual polarizations. A novel wide-band analog correlator was designed that is easily expandable for more interferometer elements. MMIC technology was used throughout as much as possible in order to miniaturize the components and to enhance mass production. These designs will find application in other upcoming astronomy projects. AMiBA is now in operations since 2006, and we are in the process to expand the array from 7 to 13 elements.Comment: 10 pages, 6 figures, ApJ in press; a version with high resolution figures available at http://www.asiaa.sinica.edu.tw/~keiichi/upfiles/AMiBA7/mtc_highreso.pd

    AMiBA Wideband Analog Correlator

    Get PDF
    A wideband analog correlator has been constructed for the Yuan-Tseh Lee Array for Microwave Background Anisotropy. Lag correlators using analog multipliers provide large bandwidth and moderate frequency resolution. Broadband IF distribution, backend signal processing and control are described. Operating conditions for optimum sensitivity and linearity are discussed. From observations, a large effective bandwidth of around 10 GHz has been shown to provide sufficient sensitivity for detecting cosmic microwave background variations.Comment: 28 pages, 23 figures, ApJ in press

    The Yuan-Tseh Lee Array for Microwave Background Anisotropy

    Full text link
    The Yuan-Tseh Lee Array for Microwave Background Anisotropy (AMiBA) is the first interferometer dedicated to studying the cosmic microwave background (CMB) radiation at 3mm wavelength. The choice of 3mm was made to minimize the contributions from foreground synchrotron radiation and Galactic dust emission. The initial configuration of seven 0.6m telescopes mounted on a 6-m hexapod platform was dedicated in October 2006 on Mauna Loa, Hawaii. Scientific operations began with the detection of a number of clusters of galaxies via the thermal Sunyaev-Zel'dovich effect. We compare our data with Subaru weak lensing data in order to study the structure of dark matter. We also compare our data with X-ray data in order to derive the Hubble constant.Comment: accepted for publication in ApJ (13 pages, 7 figures); a version with high resolution figures available at http://www.asiaa.sinica.edu.tw/~keiichi/upfiles/AMiBA7/pho_highreso.pd

    Mass and Hot Baryons in Massive Galaxy Clusters from Subaru Weak Lensing and AMiBA SZE Observations

    Full text link
    We present a multiwavelength analysis of a sample of four hot (T_X>8keV) X-ray galaxy clusters (A1689, A2261, A2142, and A2390) using joint AMiBA Sunyaev-Zel'dovich effect (SZE) and Subaru weak lensing observations, combined with published X-ray temperatures, to examine the distribution of mass and the intracluster medium (ICM) in massive cluster environments. Our observations show that A2261 is very similar to A1689 in terms of lensing properties. Many tangential arcs are visible around A2261, with an effective Einstein radius \sim 40 arcsec (at z \sim 1.5), which when combined with our weak lensing measurements implies a mass profile well fitted by an NFW model with a high concentration c_{vir} \sim 10, similar to A1689 and to other massive clusters. The cluster A2142 shows complex mass substructure, and displays a shallower profile (c_{vir} \sim 5), consistent with detailed X-ray observations which imply recent interaction. The AMiBA map of A2142 exhibits an SZE feature associated with mass substructure lying ahead of the sharp north-west edge of the X-ray core suggesting a pressure increase in the ICM. For A2390 we obtain highly elliptical mass and ICM distributions at all radii, consistent with other X-ray and strong lensing work. Our cluster gas fraction measurements, free from the hydrostatic equilibrium assumption, are overall in good agreement with published X-ray and SZE observations, with the sample-averaged gas fraction of = 0.133 \pm 0.027, for our sample = (1.2 \pm 0.1) \times 10^{15} M_{sun} h^{-1}. When compared to the cosmic baryon fraction f_b = \Omega_b/\Omega_m constrained by the WMAP 5-year data, this indicates /f_b = 0.78 \pm 0.16, i.e., (22 \pm 16)% of the baryons are missing from the hot phase of clusters.Comment: accepted for publication in ApJ; high resolution figures available at http://www.asiaa.sinica.edu.tw/~keiichi/upfiles/AMiBA7/ms_highreso.pd

    AMiBA: Sunyaev-Zel'Dovich Effect-derived Properties and Scaling Relations of Massive Galaxy Clusters

    Get PDF
    99學年度劉國欽研究獎助論文 100學年度劉國欽升等參考著作[[abstract]]The Sunyaev-Zel'dovich Effect (SZE) has been observed toward six massive galaxy clusters, at redshifts 0.091 ≤ z ≤ 0.322 in the 86-102 GHz band with the Y. T. Lee Array for Microwave Background Anisotropy (AMiBA). We modify an iterative method, based on the isothermal β models, to derive the electron temperature T e, total mass M t, gas mass M g, and integrated Compton Y within r 2500, from the AMiBA SZE data. Non-isothermal universal temperature profile (UTP) β models are also considered in this paper. These results are in good agreement with those deduced from other observations. We also investigate the embedded scaling relations, due to the assumptions that have been made in the method we adopted, between these purely SZE-deduced T e, M t, M g, and Y. Our results suggest that cluster properties may be measurable with SZE observations alone. However, the assumptions built into the pure-SZE method bias the results of scaling relation estimations and need further study.[[journaltype]]國外[[incitationindex]]SCI[[booktype]]紙本[[booktype]]電子版[[countrycodes]]US
    corecore