UBVI Surface Photometry of the Spiral Galaxy NGC 300 in the Sculptor Group

We present UBVI surface photometry for 20.'5 X 20.'5 area of a late-type spiral galaxy NGC 300. In order to understand the morphological properties and luminosity distribution characteristics of NGC 300, we have derived isophotal maps, surface brightness profiles, ellipticity profiles, position angle profiles, and color profiles. By merging the I-band data of our surface brightness measurements with those of Boeker et al. (2002) based on Hubble Space Telescope observations, we have made combined I-band surface brightness profiles for the region of 0."02 < r < 500" and decomposed the profiles into three components: a nucleus, a bulge, and an exponential disk.Comment: 16 pages(cjaa209.sty), Accepted by the Chinese J. Astron. Astrophys., Fig 2 and 8 are degraded to reduce spac

{BOAO Photometric Survey of Galactic Open Clusters. II. Physical Parameters of 12 Open Clusters

We have initiated a long-term project, the BOAO photometric survey of open clusters, to enlarge our understanding of galactic structure using UBVI CCD photometry of open clusters which have been little studied before. This is the second paper of the project in which we present the photometry of 12 open clusters. We have determined the cluster parameters by fitting the Padova isochrones to the color-magnitude diagrams of the clusters. All the clusters except for Be 0 and NGC 1348 are found to be intermediate-age to old (0.2 - 4.0 Gyrs) open clusters with a mean metallicity of [Fe/H] = 0.0.Comment: 11 page

WIYN Open Cluster Study XI: WIYN 3.5m Deep Photometry of M35 (NGC 2168)

We present deep BVI observations of the core of M35 and a nearby comparison field obtained at the WIYN 3.5m telescope under excellent seeing. These observations display the lower main sequence in BV and VI CMDs down to V = 23.3 and 24.6, respectively. At these faint magnitudes background field stars are far more numerous than the cluster stars, yet by using a smoothing technique and CMD density distribution subtraction we recover the cluster fiducial main sequence and luminosity function to V = 24.6. We find the location of the main sequence in these CMDs to be consistent with earlier work on other open clusters, specifically NGC 188, NGC 2420, and NGC 2477. We compare these open cluster fiducial sequences to stellar models by Baraffe et al. (1998), Siess et al. (2000), Girardi et al. (2000), and Yi et al. (2001) and find that the models are too blue in both B-V and V-I for stars below ~0.4 Mo. M35 contains stars to the limit of the extracted main sequence, at M ~ 0.10-0.15 Mo, suggesting that M35 may harbor a large number of brown dwarfs, which should be easy targets for near-IR instrumentation on 8-10m telescopes. We also identify a new candidate white dwarf in M35 at V = 21.36 +- 0.01. Depending on which WD models are used to interpret this cluster candidate, it is either a very high mass WD (1.05 +- 0.05 Mo) somewhat older (0.19-0.26 Gyr, 3-4 sigma) than our best isochrone age (150 Myr), or it is a modestly massive WD (0.67-0.78 Mo) much too old (0.42-0.83 Gyr) to belong to the cluster.Comment: 28 pages + 24 figures; to be published in the Sept, 2002 A

The Nature of the Density Clump in the Fornax Dwarf Spheroidal Galaxy

We have imaged the recently discovered stellar overdensity located approximately one core radius from the center of the Fornax dwarf spheroidal galaxy using the Magellan Clay 6.5m telescope with the Magellan Instant Camera (MagIC). Superb seeing conditions allowed us to probe the stellar populations of this overdensity and of a control field within Fornax to a limiting magnitude of R=26. The color-magnitude diagram of the overdensity field is virtually identical to that of the control field with the exception of the presence of a population arising from a very short (less than 300 Myr in duration) burst of star formation 1.4 Gyr ago. Coleman et al. have argued that this overdensity might be related to a shell structure in Fornax that was created when Fornax captured a smaller galaxy. Our results are consistent with this model, but we argue that the metallicity of this young component favors a scenario in which the gas was part of Fornax itself.Comment: 24 pages including 8 figures and 3 tables. Accepted by Astronomical Journa

No Open Cluster in the Ruprecht 93 Region

UBVI CCD photometry has been obtained for the Ruprecht 93 (Ru 93) region. We were unable to confirm the existence of an intermediate-age open cluster in Ru 93 from the spatial distribution of blue stars. On the other hand, we found two young star groups in the observed field: the nearer one (Ru 93 group) comprises the field young stars in the Sgr-Car arm at d ~ 2.1 kpc, while the farther one (WR 37 group) is the young stars around WR 37 at d ~ 4.8 kpc. We have derived an abnormal extinction law (Rv = 3.5) in the Ruprecht 93 region.Comment: 6 pages, 6 figures, JKAS 2010, in press (Aug issue

From the Top to the Bottom of the Main Sequence: A Complete Mass Function of the Young Open Cluster M35

We present very deep and accurate photometry of the open cluster M35 (VRIc filters). We have covered a region of 27.5x27.5 square arcmin. The data range from Ic=12.5 to 23.5 mag, and the color intervals are 0.4\le(V-I)c\le3.0, 0.5\le(R-I)c\le2.5. Roughly, these values span from 1.6 M_\odot down to the substellar limit. By using the location of the stars on color-magnitude and color-color diagrams, we have selected candidate members of this cluster. We have merged our sample with previously published data and obtained a color-magnitude diagram for the complete stellar population of the cluster, covering the spectral range early B - mid M. The Mass Function increases monotonically, when plotted in a log-log form, until it reaches ~0.8 M_\odot (\alpha=2.59). It remains shallower for less massive stars (\alpha=0.81 for 0.8-0.2 M_\odot), whereas a decrease ins observed for stars close to the substellar regime. The total mass of the cluster is ~1600 M_\odot in the area covered by this study.Comment: Accepted ApJ (Jan 10, 2001 issue

High Affinity Block of ICl,swell by Thiol-Reactive Small Molecules

Ebselen (Ebs) is considered as a glutathione peroxidase (GPx) mimetic and primarily thought to function by scavenging intracellular reactive oxygen species (ROS). Previous to our work, Deng et al. (2010a) demonstrated complete block of ICl,swell with 15 microM Ebs following endothelin-1 (ET-1) induced activation of the current in cardiomyocytes. This block was presumed to take effect mainly via the quenching of ROS. Nonetheless, our work with DI TNC1 astrocytes strongly emphasizes that Ebs might function by an alternative mechanism based on its kinetic profile in blocking ICl,swell. Our experiments showed that 45 nM Ebs can fully block ICl,swell thus suggesting an apparent IC50 result, we predicted Ebs to possess a high kon with a low koff close to zero. As predicted, Ebs failed to washout in the timescale covered by our patch-clamp experiments. The block was also distal to H2O2, previously considered as the most proximate regulator of ICl,swell. And based on further evidence demonstrating irreversible block of ICl,swell distal to H2O2 with Ebs congeners, complete suppression of native ICl,swell with MTS reagents, and failure of Ebs to block ICl,swell from the cytosol, we concluded that Ebs and its congeners can covalently modify important –SH groups required for current activation while functioning as sulfhydryl reagents. Complete irreversible block of ICl,swell with 110 mM cell impermeant MTSES in native DI TNC1 astrocytes contrasts sharply to SWELL1 (Qiu et al., 2014) or LRRC8A (Voss et al., 2014), the latest molecular entity presumably responsible for ICl,swell, where 3.33 mM MTSES failed to demonstrate block of ICl,swell in the wild-type stably expressing SWELL1 (Qiu et al., 2014). Our data with Ebs, its congeners, and MTS reagents indicate the existence of a common extracellular binding site which involves a selenenylsulfide (Se-S) bond that critically modulates ICl,swell. We, therefore, synthesized a derivative of Ebs called ebselen-para-yne (Ebs-p-yne), which provided an even higher affinity for blocking ICl,swell with a presumed IC50 ~picomolar range. Ebs-p-yne is a promising novel molecule that may serve as a tag in identifying the molecular fingerprint ultimately responsible for ICl,swell. Furthermore, we can take advantage of click chemistry to ultimately pull out the channel or channel component which has remained elusive for greater than two decades

A study of the religious educational background of oriental students in Asbury Theological Seminary in 1958-1959

https://place.asburyseminary.edu/ecommonsatsdissertations/2372/thumbnail.jp