1,473 research outputs found

    KELT-11b: A Highly Inflated Sub-Saturn Exoplanet Transiting the V=8 Subgiant HD 93396

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    We report the discovery of a transiting exoplanet, KELT-11b, orbiting the bright (V=8.0V=8.0) subgiant HD 93396. A global analysis of the system shows that the host star is an evolved subgiant star with Teff=5370±51T_{\rm eff} = 5370\pm51 K, M=1.4380.052+0.061MM_{*} = 1.438_{-0.052}^{+0.061} M_{\odot}, R=2.720.17+0.21RR_{*} = 2.72_{-0.17}^{+0.21} R_{\odot}, log g=3.7270.046+0.040g_*= 3.727_{-0.046}^{+0.040}, and [Fe/H]=0.180±0.075 = 0.180\pm0.075. The planet is a low-mass gas giant in a P=4.736529±0.00006P = 4.736529\pm0.00006 day orbit, with MP=0.195±0.018MJM_{P} = 0.195\pm0.018 M_J, RP=1.370.12+0.15RJR_{P}= 1.37_{-0.12}^{+0.15} R_J, ρP=0.0930.024+0.028\rho_{P} = 0.093_{-0.024}^{+0.028} g cm3^{-3}, surface gravity log gP=2.4070.086+0.080{g_{P}} = 2.407_{-0.086}^{+0.080}, and equilibrium temperature Teq=171246+51T_{eq} = 1712_{-46}^{+51} K. KELT-11 is the brightest known transiting exoplanet host in the southern hemisphere by more than a magnitude, and is the 6th brightest transit host to date. The planet is one of the most inflated planets known, with an exceptionally large atmospheric scale height (2763 km), and an associated size of the expected atmospheric transmission signal of 5.6%. These attributes make the KELT-11 system a valuable target for follow-up and atmospheric characterization, and it promises to become one of the benchmark systems for the study of inflated exoplanets.Comment: 15 pages, Submitted to AAS Journal

    ceritinib plus nivolumab in patients with advanced alk rearranged non small cell lung cancer results of an open label multicenter phase 1b study

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    Abstract Introduction Induction of programmed death ligand 1 (PD-L1) expression due to constitutive oncogenic signaling has been reported in NSCLC models harboring echinoderm microtubule associated protein like 4 gene (EML4)–ALK receptor tyrosine kinase gene (ALK) rearrangements. We assessed the safety and activity of ceritinib plus nivolumab in these patients. Methods In this open-label, phase 1B, multicenter, dose escalation and expansion study, previously treated (with ALK receptor tyrosine kinase [ALK] inhibitor [ALKI]/chemotherapy) or treatment-naive patients with stage IIIB or IV ALK-rearranged NSCLC received nivolumab, 3 mg/kg intravenously every 2 weeks, plus ceritinib, 450 mg/300 mg daily, with a low-fat meal. Results In total, 36 patients were treated (a 450-mg cohort [n=14] and a 300-mg cohort [n=22]). In the 450-mg cohort, four patients experienced dose-limiting toxicities. In the 300-mg cohort, two patients experienced dose-limiting toxicities. Among ALKI-naive patients, the overall response rate (ORR) was 83% (95% confidence interval [CI]: 35.9–99.6) in the 450-mg cohort and 60% (95% CI: 26.2–87.8) in the 300-mg cohort. Among ALKI-pretreated patients, the ORR was 50% (95% CI: 15.7–84.3) in the 450-mg cohort and 25% (95% CI: 5.5–57.2) in the 300-mg cohort. The ORR point estimate was observed to be greater in patients who were positive for PD-L1 than in those who were negative for PD-L1, with overlapping CIs (e.g., at a cutoff ≥1% PD-L1, 64% of patients [95% CI: 35.1–87.2] had confirmed responses as compared with those with negative PD-L1 staining (31% [95% CI: 11.0–58.7]). The most frequently reported grade 3 or 4 adverse events were increased alanine aminotransferase level (25%), increased gamma-glutamyl transferase level (22%), increased amylase level (14%), increased lipase level (11%), and maculopapular rash (11%). The incidence of all-grade rash (grouped term) was 64% in both cohorts; grade 3 rash was reported in 29% and 14% of patients in the 450-mg and 300-mg cohorts, respectively; no grade 4 rash was reported. Conclusion Ceritinib plus nivolumab has activity; ORR appears to correlate with PD-L1 at baseline. Toxicity, especially rash, is more common than with either single agent

    A direct physical interaction between Nanog and Sox2 regulates embryonic stem cell self-renewal

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    Embryonic stem (ES) cell self-renewal efficiency is determined by the Nanog protein level. However, the protein partners of Nanog that function to direct self-renewal are unclear. Here, we identify a Nanog interactome of over 130 proteins including transcription factors, chromatin modifying complexes, phosphorylation and ubiquitination enzymes, basal transcriptional machinery members, and RNA processing factors. Sox2 was identified as a robust interacting partner of Nanog. The purified Nanog–Sox2 complex identified a DNA recognition sequence present in multiple overlapping Nanog/Sox2 ChIP-Seq data sets. The Nanog tryptophan repeat region is necessary and sufficient for interaction with Sox2, with tryptophan residues required. In Sox2, tyrosine to alanine mutations within a triple-repeat motif (S X T/S Y) abrogates the Nanog–Sox2 interaction, alters expression of genes associated with the Nanog-Sox2 cognate sequence, and reduces the ability of Sox2 to rescue ES cell differentiation induced by endogenous Sox2 deletion. Substitution of the tyrosines with phenylalanine rescues both the Sox2–Nanog interaction and efficient self-renewal. These results suggest that aromatic stacking of Nanog tryptophans and Sox2 tyrosines mediates an interaction central to ES cell self-renewal

    Empirical comparison of cross-platform normalization methods for gene expression data

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    <p>Abstract</p> <p>Background</p> <p>Simultaneous measurement of gene expression on a genomic scale can be accomplished using microarray technology or by sequencing based methods. Researchers who perform high throughput gene expression assays often deposit their data in public databases, but heterogeneity of measurement platforms leads to challenges for the combination and comparison of data sets. Researchers wishing to perform cross platform normalization face two major obstacles. First, a choice must be made about which method or methods to employ. Nine are currently available, and no rigorous comparison exists. Second, software for the selected method must be obtained and incorporated into a data analysis workflow.</p> <p>Results</p> <p>Using two publicly available cross-platform testing data sets, cross-platform normalization methods are compared based on inter-platform concordance and on the consistency of gene lists obtained with transformed data. Scatter and ROC-like plots are produced and new statistics based on those plots are introduced to measure the effectiveness of each method. Bootstrapping is employed to obtain distributions for those statistics. The consistency of platform effects across studies is explored theoretically and with respect to the testing data sets.</p> <p>Conclusions</p> <p>Our comparisons indicate that four methods, DWD, EB, GQ, and XPN, are generally effective, while the remaining methods do not adequately correct for platform effects. Of the four successful methods, XPN generally shows the highest inter-platform concordance when treatment groups are equally sized, while DWD is most robust to differently sized treatment groups and consistently shows the smallest loss in gene detection. We provide an R package, CONOR, capable of performing the nine cross-platform normalization methods considered. The package can be downloaded at <url>http://alborz.sdsu.edu/conor</url> and is available from CRAN.</p

    KELT-22Ab: A Massive, Short-Period Hot Jupiter Transiting a Near-solar Twin

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    We present the discovery of KELT-22Ab, a hot Jupiter from the KELT-South survey. KELT-22Ab transits the moderately bright (V ∼ 11.1) Sun-like G2V star TYC 7518-468-1. The planet has an orbital period of days, a radius of , and a relatively large mass of . The star has , , K, (cgs), and [m/H] = ; thus other than its slightly super-solar metallicity, it appears to be a near-solar twin. Surprisingly, KELT-22A exhibits kinematics and a Galactic orbit that are somewhat atypical for thin-disk stars. Nevertheless, the star is rotating rapidly for its estimated age, and shows evidence of chromospheric activity. Imaging reveals a slightly fainter companion to KELT-22A that is likely bound, with a projected separation of 6″ (∼1400 au). In addition to the orbital motion caused by the transiting planet, we detect a possible linear trend in the radial velocity of KELT-22A, suggesting the presence of another relatively nearby body that is perhaps non-stellar. KELT-22Ab is highly irradiated (as a consequence of the small semimajor axis of ), and is mildly inflated. At such small separations, tidal forces become significant. The configuration of this system is optimal for measuring the rate of tidal dissipation within the host star. Our models predict that, due to tidal forces, the semimajor axis is decreasing rapidly, and KELT-22Ab is predicted to spiral into the star within the next Gyr

    Expression signatures of TP53 mutations in serous ovarian cancers

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    <p>Abstract</p> <p>Background</p> <p>Mutations in the <it>TP53 </it>gene are extremely common and occur very early in the progression of serous ovarian cancers. Gene expression patterns that relate to mutational status may provide insight into the etiology and biology of the disease.</p> <p>Methods</p> <p>The <it>TP53 </it>coding region was sequenced in 89 frozen serous ovarian cancers, 40 early stage (I/II) and 49 advanced stage (III/IV). Affymetrix U133A expression data was used to define gene expression patterns by mutation, type of mutation, and cancer stage.</p> <p>Results</p> <p>Missense or chain terminating (null) mutations in <it>TP53 </it>were found in 59/89 (66%) ovarian cancers. Early stage cancers had a significantly higher rate of null mutations than late stage disease (38% vs. 8%, p < 0.03). In advanced stage cases, mutations were more prevalent in short term survivors than long term survivors (81% vs. 30%, p = 0.0004). Gene expression patterns had a robust ability to predict <it>TP53 </it>status within training data. By using early versus late stage disease for out of sample predictions, the signature derived from early stage cancers could accurately (86%) predict mutation status of late stage cancers.</p> <p>Conclusions</p> <p>This represents the first attempt to define a genomic signature of <it>TP53 </it>mutation in ovarian cancer. Patterns of gene expression characteristic of <it>TP53 </it>mutation could be discerned and included several genes that are known p53 targets or have been described in the context of expression signatures of <it>TP53 </it>mutation in breast cancer.</p

    Encoding optical control in LCK kinase to quantitatively investigate its activity in live cells.

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    LCK is a tyrosine kinase that is essential for initiating T-cell antigen receptor (TCR) signaling. A complete understanding of LCK function is constrained by a paucity of methods to quantitatively study its function within live cells. To address this limitation, we generated LCK*, in which a key active-site lysine is replaced by a photocaged equivalent, using genetic code expansion. This strategy enabled fine temporal and spatial control over kinase activity, thus allowing us to quantify phosphorylation kinetics in situ using biochemical and imaging approaches. We find that autophosphorylation of the LCK active-site loop is indispensable for its catalytic activity and that LCK can stimulate its own activation by adopting a more open conformation, which can be modulated by point mutations. We then show that CD4 and CD8, T-cell coreceptors, can enhance LCK activity, thereby helping to explain their effect in physiological TCR signaling. Our approach also provides general insights into SRC-family kinase dynamics
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