Cell Death Induction by Targeting Tumor Metabolism

Over the last century, a broader interest in the topic of tumor metabolism has emerged. From the 1920s onward, when Otto Warburg proposed increased aerobic glycolysis of tumor cells, a deeper understanding has established that tumor cells have an altered metabolism which is directly linked to cancer progression. It was soon discovered that not only do environmental changes lead to alterations in metabolism but that oncogenes have a profound influence in these alterations. They not only induce nutrient uptake and synthesis of proteins and DNA but can lead to a switch toward glycolysis, which identifies them as a major player in tumor metabolism. These observations have raised the interest to target metabolic pathways for cancer therapy and, interestingly, some of the first discovered chemotherapeutics target metabolic pathways and are still in clinic. Concerns that these targets will also affect normal cells has intensified research to understand how changes in tumor metabolism promote tumor growth and which enzymes and signaling pathways are involved. These observations led to the discovery of new targets and drugs that specifically affect tumor metabolism and can exploit the dependence of tumor cells on the metabolic changes

Photometry Results for the Globular Clusters M10 and M12: Extinction Maps, Color-Magnitude Diagrams, and Variable Star Candidates

We report on photometry results of the equatorial globular clusters (GCs) M10 and M12. These two clusters are part of our sample of GCs which we are probing for the existence of photometrically varying eclipsing binary stars. During the search for binaries in M10 and M12, we discovered the signature of differential reddening across the fields of the clusters. The effect is stronger for M10 than for M12. Using our previously described dereddening technique, we create differential extinction maps for the clusters which dramatically improve the appearance of the color-magnitude diagrams (CMDs). Comparison of our maps with the dust emissivity maps of Schlegel, Finkbeiner, & Davis (SFD) shows good agreement in terms of spatial extinction features. Several methods of adding an E_{V-I} zero point to our differential maps are presented of which isochrone fitting proved to be the most successful. Our E_{V-I} values fall within the range of widely varying literature values. More specifically, our reddening zero point estimate for M12 agrees well with the SFD estimate, whereas the one for M10 falls below the SFD value. Our search for variable stars in the clusters produced a total of five variables: three in M10 and two in M12. The M10 variables include a binary system of the W Ursa Majoris (W UMa) type, a background RR Lyrae star, and an SX Phoenicis pulsator, none of which is physically associated with M10. M12's variables are two W UMa binaries, one of which is most likely a member of the cluster. We present the phased photometry lightcurves for the variable stars, estimate their distances, and show their locations in the fields and the CMDs of the GCs.Comment: 22 pages, 21 figures, to be published in AJ October 2002. For a higher-resolution version of this paper, please visit http://www.astro.lsa.umich.edu/~kaspar/M10_M12_photometry.ps.gz (gzipped postscript) or http://www.astro.lsa.umich.edu/~kaspar/M10_M12_photometry.pdf (pdf file

Variable Stars in the Field of the Globular Cluster NGC 3201

We report on the discovery and analysis of 14 short-period variable stars in the field of the southern globular cluster NGC 3201, located within roughly two magnitudes on either side of the main-sequence turnoff. 11 of these variable stars are eclipsing binaries, one is an RR Lyrae, and two are thus far unclassified systems. Among the eclipsing binary stars, nine are of the W Ursa Majoris (W UMa) type, one an Algol (EA) system, and one a detached system. Using spectroscopic follow-up observations as well as analysis of the variables' locations in the color-magnitude diagram of the cluster, we find that only one variable star (a W UMa type blue straggler) is actually a member of NGC 3201. We present the phased photometry lightcurves for all the variable star systems as well as their locations in the field-of-view and in the color-magnitude diagram.Comment: 18 pages, 8 figures, 3 tables; accepted for the January 2002 issue of AJ. For full resolution versions of this paper, go to: http://www.astro.lsa.umich.edu/users/kaspar/html/vars3201.ps.gz or http://www.astro.lsa.umich.edu/users/kaspar/html/vars3201.pd

Structure Effects on Coulomb Dissociation of 8^8B

Coulomb Dissociation provides an alternative method for determining the radiative capture cross sections at astrophysically relevant low relative energies. For the breakup of $^8$B on $^{58}$Ni, we calculate the total Coulomb Dissociation cross section and the angular distribution for E1, E2 and M1. Our calculations are performed first within the standard first order semiclassical theory of Coulomb Excitation, including the correct three body kinematics, and later including the projectile-target nuclear interactions.Comment: 6 pages, proceedings from International Workshop on RNB, Puri, India, January 1998 - to be published in J. Phys.

Dominance of Nuclear Processes in the Dissociation of 8B

We study the break-up of 8B in collisions with heavy-ions. The process is described in terms of inelastic excitations leading to states in the continuum. The effects of the nuclear and coulomb fields are included on the same footing in the microscopic construction of the transition matrix elements. The interplay between coulomb and nuclear excitation processes differs significantly from the situation encountered in reactions involving systems close to the stability line. In particular, nuclear excitation is found to remain predominant at energies well below the coulomb barrier,Comment: TEX file + 11 postscript figure

Detecting Variability in Massive Astronomical Time-Series Data I: application of an infinite Gaussian mixture model

We present a new framework to detect various types of variable objects within massive astronomical time-series data. Assuming that the dominant population of objects is non-variable, we find outliers from this population by using a non-parametric Bayesian clustering algorithm based on an infinite GaussianMixtureModel (GMM) and the Dirichlet Process. The algorithm extracts information from a given dataset, which is described by six variability indices. The GMM uses those variability indices to recover clusters that are described by six-dimensional multivariate Gaussian distributions, allowing our approach to consider the sampling pattern of time-series data, systematic biases, the number of data points for each light curve, and photometric quality. Using the Northern Sky Variability Survey data, we test our approach and prove that the infinite GMM is useful at detecting variable objects, while providing statistical inference estimation that suppresses false detection. The proposed approach will be effective in the exploration of future surveys such as GAIA, Pan-Starrs, and LSST, which will produce massive time-series data.Comment: accepted for publication in MNRA

Detection of spectral evolution in the bursts emitted during the 2008-2009 active episode of SGR J1550 - 5418

In early October 2008, the Soft Gamma Repeater SGRJ1550 - 5418 (1E 1547.0 - 5408, AXJ155052 - 5418, PSR J1550 - 5418) became active, emitting a series of bursts which triggered the Fermi Gamma-ray Burst Monitor (GBM) after which a second especially intense activity period commenced in 2009 January and a third, less active period was detected in 2009 March-April. Here we analyze the GBM data all the bursts from the first and last active episodes. We performed temporal and spectral analysis for all events and found that their temporal characteristics are very similar to the ones of other SGR bursts, as well the ones reported for the bursts of the main episode (average burst durations \sim 170 ms). In addition, we used our sample of bursts to quantify the systematic uncertainties of the GBM location algorithm for soft gamma-ray transients to < 8 deg. Our spectral analysis indicates significant spectral evolution between the first and last set of events. Although the 2008 October events are best fit with a single blackbody function, for the 2009 bursts an Optically Thin Thermal Bremsstrahlung (OTTB) is clearly preferred. We attribute this evolution to changes in the magnetic field topology of the source, possibly due to effects following the very energetic main bursting episode.Comment: 17 pages, 7 figures, 2 table

Characterization of CoRoT Target Fields with the Berlin Exoplanet Search Telescope: Identification of Periodic Variable Stars in the LRa1 Field

In this paper, we report on observations of the CoRoT LRa1 field with the Berlin Exoplanet Search Telescope (BEST). The current paper is part of a series of papers describing the results of our stellar variability survey. The BEST is a small aperture telescope with a wide field of view (FOV). It is dedicated to searching for stellar variability within the target fields of the CoRoT space mission to aid in minimizing false-alarm rates and identify potential targets for additional science. The LRa1 field is CoRoT's second long run field located in the galactic anticenter direction. We observed the LRa1 stellar field on 23 nights between November and March 2005/2006. From 6099 stars marked as variable, 39 were classified as periodic variable stars and 27 of them are within the CoRoT FOV. We also confirmed the variability for four stars listed in the General Catalogue of Variable Stars (GCVS)

Structure effects on the Coulomb dissociation of 8B at relativistic energies

We investigate the Coulomb dissociation of 8B on 208Pb target at the beam energy of 250 MeV/nucleon, employing the cross sections for the radiative capture reaction 7Be(p,gamma)8B calculated within the Shell Model Embedded in the Continuum (SMEC) approach. In contrast to the situation at lower beam energies, the Coulomb breakup cross sections are found to be sensitive to the M1 transitions. Comparisons of SMEC and single-particle potential model predictions show that the Coulomb breakup cross sections at these high energies are sensitive to the structure model of 8B. Analysis of the preliminary data taken recently at GSI reveal that E2 multipolarity contributes up to 25 % to the cross sections even for the relative energies of p - 7Be below 0.25 MeV.Comment: 22 pages, 7 figure

Twinsol: A dual superconducting solenoid system for low-energy radioactive nuclear beam research

A unique type of apparatus is currently under construction as part of an upgrade to the radioactive ion beam facility at the University of Notre Dame Nuclear Structure Laboratory. The device will consist of a pair of large in-line superconducting solenoids (B0 = 6 tesla,B0=6tesla, bore=30 cmbore=30cm) which will be used to produce, collect, transport, focus and analyze both stable and radioactive nuclear beams. This apparatus in conjunction with the recently upgraded accelerators at Notre Dame is especially well suited for the production and utilization of intense (viz. >106/sec>106/sec), low-energy (1–10 MeV/u), stable and radioactive nuclear beams relevant to the study of reactions involved in astrophysical processes. These improvements will allow for the production of radioactive beams of greater intensity, higher purity and at both higher and lower energies than previously available at this facility. The first phase of construction and results of initial tests will be reported. © 1997 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87534/2/397_1.pd