405 research outputs found

    BASIGIN-2 MEDIATED ACTIVATION OF ERK1/2 SIGNALING IN HUMAN GLIOBLASTOMA MULTIFORME CELLS

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    Glioblastoma multiforme (GBM) is the most common malignant form of human brain cancer. GBM tumor cells overexpress the protein Basigin (Bsg) at the cell surface where it contributes to malignancy via stimulation of matrix metalloproteinase (MMP) expression in surrounding normal tissues, resulting in the degradation of the extracellular matrix (ECM) surrounding tumors, promoting remodeling of the tumor borders, stimulating growth. In work by Belton et al. (2008), human uterine endometrial cells treated with a recombinant form of human basigin possessing the extracellular domain of the Bsg protein (rBsg-ECD) showed activation of the Mitogen-Activated Protein Kinase (MAPK) signaling pathway proteins, ERK1/2. This effect was mediated by rBsg-ECD binding to the Basigin-2 (Bsg-2) at the cell surface. In this research, U87-MG human GBM cells were treated with purified rBsg-ECD protein to measure changes in the phosphorylation of the ERK1/2 proteins. The results indicate the presence of a signaling loop within GBM tumors where soluble Bsg protein stimulates signal transduction through Bsg-2 at the cell surface. rBsg-mediated ERK1/2 stimulation is inhibited by the antioxidant compound Resveratrol, suggesting that the signaling mechanism through Bsg-2 involves the Epidermal Growth Factor Receptor (EGFR). Taken together, these results indicate that soluble Basigin protein stimulates signaling events through the MAPK signaling pathway by binding to Bsg-2 on the surface of GBM cells

    Humility in Leadership: Abandoning the Pursuit of Unattainable Perfection

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    Chapter on humility and leadership by Hoekstra, Bell, and Peterson in S.A. Quatro & R. R. Sims (Eds.), Executive Ethics: Ethical Dilemmas and Challenges for the C-Suite. Greenwich, CT: Information Age Publishing, 2008

    Amalgame: Cosmological Constraints from the First Combined Photometric Supernova Sample

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    Future constraints of cosmological parameters from Type Ia supernovae (SNe Ia) will depend on the use of photometric samples, those samples without spectroscopic measurements of the SNe Ia. There is a growing number of analyses that show that photometric samples can be utilised for precision cosmological studies with minimal systematic uncertainties. To investigate this claim, we perform the first analysis that combines two separate photometric samples, SDSS and Pan-STARRS, without including a low-redshift anchor. We evaluate the consistency of the cosmological parameters from these two samples and find they are consistent with each other to under 1Ļƒ1\sigma. From the combined sample, named Amalgame, we measure Ī©M=0.328Ā±0.024\Omega_M = 0.328 \pm 0.024 with SN alone in a flat Ī›\LambdaCDM model, and Ī©M=0.330Ā±0.018\Omega_M = 0.330 \pm 0.018 and w=āˆ’1.016āˆ’0.058+0.055w = -1.016^{+0.055}_{-0.058} when combining with a Planck data prior and a flat wwCDM model. These results are consistent with constraints from the Pantheon+ analysis of only spectroscopically confirmed SNe Ia, and show that there are no significant impediments to analyses of purely photometric samples of SNe Ia.Comment: Submitting to MNRAS; comments welcom

    The DEHVILS Survey Overview and Initial Data Release: High-Quality Near-Infrared Type Ia Supernova Light Curves at Low Redshift

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    While the sample of optical Type Ia Supernova (SN Ia) light curves (LCs) usable for cosmological parameter measurements surpasses 2000, the sample of published, cosmologically viable near-infrared (NIR) SN Ia LCs, which have been shown to be good "standard candles," is still ā‰²\lesssim 200. Here, we present high-quality NIR LCs for 83 SNe Ia ranging from 0.002<z<0.090.002 < z < 0.09 as a part of the Dark Energy, H0_0, and peculiar Velocities using Infrared Light from Supernovae (DEHVILS) survey. Observations are taken using UKIRT's WFCAM, where the median depth of the images is 20.7, 20.1, and 19.3 mag (Vega) for YY, JJ, and HH-bands, respectively. The median number of epochs per SN Ia is 18 for all three bands (YJHYJH) combined and 6 for each band individually. We fit 47 SN Ia LCs that pass strict quality cuts using three LC models, SALT3, SNooPy, and BayeSN and find scatter on the Hubble diagram to be comparable to or better than scatter from optical-only fits in the literature. Fitting NIR-only LCs, we obtain standard deviations ranging from 0.128-0.135 mag. Additionally, we present a refined calibration method for transforming 2MASS magnitudes to WFCAM magnitudes using HST CALSPEC stars that results in a 0.03 mag shift in the WFCAM YY-band magnitudes.Comment: 24 pages, 9 figures. Accepted by MNRA

    A measurement of the millimetre emission and the Sunyaev-Zel'dovich effect associated with low-frequency radio sources

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    We present a statistical analysis of the millimetre-wavelength properties of 1.4GHz-selected sources and a detection of the Sunyaevā€“Zelā€™dovich (SZ) effect associated with the haloes that host them. We stack data at 148, 218 and 277GHz from the Atacama Cosmology Telescope at the positions of a large sample of radio AGN selected at 1.4GHz. The thermal SZ effect associated with the haloes that host the AGN is detected at the 5Ļƒ level through its spectral signature, representing a statistical detection of the SZ effect in some of the lowest mass haloes (average M 200 ā‰ˆ 10 13 M. h āˆ’1 70 ) studied to date. The relation between the SZ effect and mass (based on weak lensing measurements of radio galaxies) is consistent with that measured by Planck for local bright galaxies. In the context of galaxy evolution models, this study confirms that galaxies with radio AGN also typically support hot gaseous haloes. Adding Herschel observations allows us to show that the SZ signal is not significantly contaminated by dust emission. Finally, we analyse the contribution of radio sources to the angular power spectrum of the cosmic microwave background

    A 2 Earth Radius Planet Orbiting the Bright Nearby K-Dwarf Wolf 503

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    Since its launch in 2009, the Kepler telescope has found thousands of planets with radii between that of Earth and Neptune. Recent studies of the distribution of these planets have revealed a rift in the population near 1.5-2.0Rā؁R_{\bigoplus}, informally dividing these planets into "super-Earths" and "sub-Neptunes". The origin of this division is not well understood, largely because the majority of planets found by Kepler orbit distant, dim stars and are not amenable to radial velocity follow-up or transit spectroscopy, making bulk density and atmospheric measurements difficult. Here, we present the discovery and validation of a newly found 2.03āˆ’0.07+0.08Ā Rā؁2.03^{+0.08}_{-0.07}~R_{\bigoplus} planet in direct proximity to the radius gap, orbiting the bright (J=8.32J=8.32~mag), nearby (D=44.5D=44.5~pc) high proper motion star Wolf 503 (EPIC 212779563). We classify Wolf 503 as a K3.5V star and member of the thick disc population. We determine the possibility of a companion star and false positive detection to be extremely low using both archival images and high-contrast adaptive optics images from the Palomar observatory. The brightness of the host star makes Wolf 503b a prime target for prompt radial velocity follow-up, HST transit spectroscopy, as well as detailed atmospheric characterization with JWST. With its measured radius near the gap in the planet radius and occurrence rate distribution, Wolf 503b offers a key opportunity to better understand the origin of this radius gap as well as the nature of the intriguing populations of "super-Earths" and "sub-Neptunes" as a whole
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