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Search Results: 1 - 10 of 25318 matches for " Juna Lee "
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Role of Media in Provoking Cigarette Smoking among Adolescents in Urban Nepal  [PDF]
Sushma Dahal, Sabeena Maharjan, Raj Kumar Subedi, Juna Maharjan
Health (Health) , 2015, DOI: 10.4236/health.2015.71011
Abstract: At current era of globalization, media is the double edged sword that is important both for health education as well as the stimulation of unhealthy behaviour. In Nepal, though there is ban on most forms of advertising, it is not clear about placement of tobacco advertisement in TV, films and other forms of media. Studies about cigarette smoking and its association with media are inadequate in Nepal. The objective of this study was to explore the role of media in cigarette smoking habit of adolescents in Nepal. A cross-sectional study was conducted among 394 adolescent students by using questionnaire method in 3 randomly selected colleges of Kathmandu district, Nepal. Data were analysed by using bivariate and multinomial logistic regression analysis. Statistically significant relationship at 95% CI was found between cigarette smoking status and media related variables like: seeing cigarette advertisement, reading fashion magazine, attending musical program sponsored by cigarette companies, watching movies in cinema hall, liking heavy metal/hard rock music, television watching time and desire to smoke if favourite artist smokes. Multinomial logistic regression showed that those with high receptivity to cigarette advertisement were likely to be current smokers (OR = 71.416, CI: 8.796 - 579.823) and ever smokers (OR = 9.582, CI: 2.201 - 41.714) compared to never smokers. About 79% of respondents agreed that media teaches different ways of smoking to its audiences. Different forms of media including cinema, music, magazines, television, games and music sponsorship are found to be important predictors for smoking status of college students in urban Nepal. Thus smoking prevention activities should consider role of media in smoking provocation among adolescents.
Neurofilament Heavy Polypeptide Regulates the Akt-β-Catenin Pathway in Human Esophageal Squamous Cell Carcinoma
Myoung Sook Kim,Xiaofei Chang,Cynthia LeBron,Jatin K. Nagpal,Juna Lee,Yiping Huang,Keishi Yamashita,Barry Trink,Edward A. Ratovitski,David Sidransky
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0009003
Abstract: Aerobic glycolysis and mitochondrial dysfunction are common features of aggressive cancer growth. We observed promoter methylation and loss of expression in neurofilament heavy polypeptide (NEFH) in a significant proportion of primary esophageal squamous cell carcinoma (ESCC) samples that were of a high tumor grade and advanced stage. RNA interference-mediated knockdown of NEFH accelerated ESCC cell growth in culture and increased tumorigenicity in vivo, whereas forced expression of NEFH significantly inhibited cell growth and colony formation. Loss of NEFH caused up-regulation of pyruvate kinase-M2 type and down-regulation of pyruvate dehydrogenase, via activation of the Akt/β-catenin pathway, resulting in enhanced aerobic glycolysis and mitochondrial dysfunction. The acceleration of glycolysis and mitochondrial dysfunction in NEFH-knockdown cells was suppressed in the absence of β-catenin expression, and was decreased by the treatment of 2-Deoxyglucose, a glycolytic inhibitor, or API-2, an Akt inhibitor. Loss of NEFH activates the Akt/β-catenin pathway and increases glycolysis and mitochondrial dysfunction. Cancer cells with methylated NEFH can be targeted for destruction with specific inhibitors of deregulated downstream pathways.
Cysteine Dioxygenase 1 Is a Tumor Suppressor Gene Silenced by Promoter Methylation in Multiple Human Cancers
Mariana Brait, Shizhang Ling, Jatin K. Nagpal, Xiaofei Chang, Hannah Lui Park, Juna Lee, Jun Okamura, Keishi Yamashita, David Sidransky, Myoung Sook Kim
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0044951
Abstract: The human cysteine dioxygenase 1 (CDO1) gene is a non-heme structured, iron-containing metalloenzyme involved in the conversion of cysteine to cysteine sulfinate, and plays a key role in taurine biosynthesis. In our search for novel methylated gene promoters, we have analyzed differential RNA expression profiles of colorectal cancer (CRC) cell lines with or without treatment of 5-aza-2′-deoxycytidine. Among the genes identified, the CDO1 promoter was found to be differentially methylated in primary CRC tissues with high frequency compared to normal colon tissues. In addition, a statistically significant difference in the frequency of CDO1 promoter methylation was observed between primary normal and tumor tissues derived from breast, esophagus, lung, bladder and stomach. Downregulation of CDO1 mRNA and protein levels were observed in cancer cell lines and tumors derived from these tissue types. Expression of CDO1 was tightly controlled by promoter methylation, suggesting that promoter methylation and silencing of CDO1 may be a common event in human carcinogenesis. Moreover, forced expression of full-length CDO1 in human cancer cells markedly decreased the tumor cell growth in an in vitro cell culture and/or an in vivo mouse model, whereas knockdown of CDO1 increased cell growth in culture. Our data implicate CDO1 as a novel tumor suppressor gene and a potentially valuable molecular marker for human cancer.
SEGUE-2 Limits on Metal-Rich Old-Population Hypervelocity Stars In the Galactic Halo
Juna A. Kollmeier,Andrew Gould,Constance Rockosi,Timothy C. Beers,Gillian Knapp,Jennifer A. Johnson,Heather Morrison,Paul Harding,Young Sun Lee,Benjamin A. Weaver
Physics , 2010, DOI: 10.1088/0004-637X/723/1/812
Abstract: We present new limits on the ejection of metal-rich old-population hypervelocity stars from the Galactic center (GC) as probed by the SEGUE-2 survey. Our limits are a factor of 3-10 more stringent than previously reported, depending on stellar type. Compared to the known population of B-star ejectees, there can be no more than 30 times more metal-rich old-population F/G stars ejected from the GC. Because B stars comprise a tiny fraction of a normal stellar population, this places significant limits on a combination of the GC mass function and the ejection mechanism for hypervelocity stars. In the presence of a normal GC mass function, our results require an ejection mechanism that is about 5.5 times more efficient at ejecting B-stars compared to low-mass F/G stars.
Expression of Aquaporin 5 (AQP5) Promotes Tumor Invasion in Human Non Small Cell Lung Cancer
Young Kwang Chae, Janghee Woo, Mi-Jung Kim, Sung Koo Kang, Myoung Sook Kim, Juna Lee, Seung Koo Lee, Gyungyub Gong, Yong Hee Kim, Jean Charles Soria, Se Jin Jang, David Sidransky, Chulso Moon
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0002162
Abstract: The aquaporins (AQP) are water channel proteins playing a major role in transcellular and transepithelial water movement. Recently, the role of AQPs in human carcinogenesis has become an area of great interest. Here, by immunohistochemistry (IHC), we have found an expression of AQP5 protein in 35.3% (IHC-score: ≥1, 144/408) of the resected NSCLC tissue samples. Cases with AQP5-positive status (IHC-score: ≥2) displayed a higher rate of tumor recurrence than negative ones in NSCLC (54.7% vs. 35.1%, p = 0.005) and worse disease-free survival (p = 0.033; OR = 1.52; 95%CI:1.04?2.23). Further in vitro invasion assay using BEAS-2B and NIH3T3 cells stably transfected with overexpression constructs for full length wild-type AQP5 (AQP5) and its two mutants, N185D which blocks membrane trafficking and S156A which blocks phosphorylation on Ser156, showed that AQP5 induced cell invasions while both mutants did not. In BEAS-2B cells, the expression of AQP5 caused a spindle-like and fibroblastic morphologic change and losses of cell-cell contacts and cell polarity. Only cells with AQP5, not either of two mutants, exhibited a loss of epithelial cell markers and a gain of mesenchymal cell markers. In a human SH3-domains protein array, cellular extracts from BEAS-2B with AQP5 showed a robust binding activity to SH3-domains of the c-Src, Lyn, and Grap2 C-terminal. Furthermore, in immunoprecipitation assay, activated c-Src, phosphorylated on Tyr416, showed a stronger binding activity to cellular extracts from BEAS-2B with AQP5 compared with N185D or S156A mutant. Fluorescence in situ hybridization (FISH) analysis failed to show evidence of genomic amplification, suggesting AQP5 expression as a secondary event. Based on these clinical and molecular observations, we conclude that AQP5, through its phosphorylation on Ser156 and subsequent interaction with c-Src, plays an important role in NSCLC invasion and, therefore, may provide a unique opportunity for developing a novel therapeutic target as well as a prognostic marker in NSCLC.
The star capture model for fueling quasar accretion disks
Gareth F. Kennedy,Jordi Miralda-Escudé,Juna A. Kollmeier
Physics , 2010, DOI: 10.1017/S1743921311017893
Abstract: Although the powering mechanism for quasars is now widely recognized to be the accretion of matter in a geometrically thin disk, the transport of matter to the inner region of the disk where luminosity is emitted remains an unsolved question. Miralda-Escud\'e & Kollmeier (2005) proposed a model whereby quasars are fuelled when stars are captured by the accretion disk as they plunge through the gas. Such plunging stars can then be destroyed and deliver their mass to the accretion disk. Here we present the first detailed calculations for the capture of stars originating far from the accretion disk near the zone of influence of the central black hole. In particular we examine the effect of adding a perturbing mass to a fixed stellar cusp potential on bringing stars into the accretion disk where they can be captured. The work presented here will be discussed in detail in an upcoming publication Kennedy et al. (2010).
The Galaxy Proximity Effect in the Lyman-alpha Forest
Juna A. Kollmeier,David H. Weinberg,Romeel Dave',Neal Katz
Physics , 2002, DOI: 10.1063/1.1581790
Abstract: Hydrodynamic cosmological simulations predict that the average opacity of the Ly-alpha forest should increase in the neighborhood of galaxies because galaxies form in dense environments. Recent observations (Adelberger et al. 2002) confirm this expectation at large scales, but they show a decrease of absorption at comoving separations Delta_r <~ 1 Mpc/h. We show that this discrepancy is statistically significant, especially for the innermost data point at Delta_r <= 0.5 Mpc/h, even though this data point rests on three galaxy-quasar pairs. Galaxy redshift errors of the expected magnitude are insufficient to resolve the conflict. Peculiar velocities allow gas at comoving distances >~ 1 Mpc/h to produce saturated absorption at the galaxy redshift, putting stringent requirements on any ``feedback'' solution. Local photoionization is insufficient, even if we allow for recurrent AGN activity that keeps the neutral hydrogen fraction below its equilibrium value. A simple ``wind'' model that eliminates all neutral hydrogen in spheres around the observed galaxies can marginally explain the data, but only if the winds extend to comoving radii ~1.5 Mpc/h.
Lyman Break Galaxies and the Lyman-alpha Forest
Juna A. Kollmeier,David H. Weinberg,Romeel Dave',Neal Katz
Physics , 2002, DOI: 10.1086/376789
Abstract: We use hydrodynamic simulations to predict correlations between Lya forest absorption and galaxies at redshift z~3. The probability distribution function (PDF) of Lya flux decrements shifts systematically towards higher values in the vicinity of galaxies, reflecting the overdense environments in which these galaxies reside. The predicted signal remains strong in spectra smoothed over 50-200 km/s, allowing tests with moderate resolution quasar spectra. The strong bias of high redshift galaxies towards high density regions imprints a clear signature on the flux PDF, but the predictions are not sensitive to galaxy baryon mass or star formation rate, and they are similar for galaxies and for dark matter halos. The dependence of the flux PDF on galaxy proximity is sensitive to redshift determination errors, with rms errors of 150-300 km/s substantially weakening the predicted trends. On larger scales, the mean galaxy overdensity in a cube of 5 or 10 Mpc/h (comoving) is strongly correlated with the mean Lya flux decrement on a line of sight through the cube center. The slope of the correlation is ~3 times steeper for galaxies than for dark matter as a result of galaxy bias. The predicted large scale correlation is in qualitative agreement with recently reported observational results. However, observations also show a drop in absorption in the immediate vicinity of galaxies, which our models do not predict even if we allow the galaxies or AGNs within them to be ionizing sources. This decreased absorption could be a signature of galaxy feedback on the surrounding IGM, perhaps via galactic winds. Peculiar velocities often allow gas at comoving distances ~1.5 Mpc/h to produce saturated absorption at the galaxy redshift, so any feedback mechanism must suppress neutral hydrogen out to these radii to match the data. (Abridged)
Calcium-rich Gap Transients: Solving the Calcium Conundrum in the Intracluster Medium
John S. Mulchaey,Mansi M. Kasliwal,Juna A. Kollmeier
Physics , 2014, DOI: 10.1088/2041-8205/780/2/L34
Abstract: X-ray measurements suggest the abundance of Calcium in the intracluster medium is higher than can be explained using favored models for core-collapse and Type Ia supernovae alone. We investigate whether the Calcium conundrum in the intracluster medium can be alleviated by including a contribution from the recently discovered subclass of supernovae known as Calcium-rich gap transients. Although the Calcium-rich gap transients make up only a small fraction of all supernovae events, we find that their high Calcium yields are sufficient to reproduce the X-ray measurements found for nearby rich clusters. We find the $\chi^{2}$ goodness-of-fit metric improves from 84 to 2 by including this new class. Moreover, Calcium-rich supernovae preferentially occur in the outskirts of galaxies making it easier for the nucleosynthesis products of these events to be incorporated in the intracluster medium via ram-pressure stripping. The discovery of a Calcium-rich gap transients in clusters and groups far from any individual galaxy suggests supernovae associated with intracluster stars may play an important role in enriching the intracluster medium. Calcium-rich gap transients may also help explain anomalous Calcium abundances in many other astrophysical systems including individual stars in the Milky Way, the halos of nearby galaxies and the circumgalactic medium. Our work highlights the importance of considering the diversity of supernovae types and corresponding yields when modeling the abundance of the intracluster medium and other gas reservoirs.
Warm-hot gas in groups and galaxies toward H2356-309
Rik J. Williams,John S. Mulchaey,Juna A. Kollmeier
Physics , 2012, DOI: 10.1088/2041-8205/762/1/L10
Abstract: We present a detailed analysis of the galaxy and group distributions around three reported X-ray absorption line systems in the spectrum of the quasar H2356-309. Previous studies associated these absorbers with known large-scale galaxy structures (i.e., walls and filaments) along the line of sight. Such absorption lines typically trace 10^{5-7} K gas, and may be evidence of the elusive warm-hot intergalactic medium (WHIM) thought to harbor the bulk of the low-redshift "missing baryons;" alternatively, they may be linked to individual galaxies or groups in the filaments. Here we combine existing galaxy survey data with new, multi-object Magellan spectroscopy to investigate the detailed galaxy distribution near each absorber. All of these three absorption systems are within the projected virial radii of nearby galaxies and/or groups, and could therefore arise in these virialized structures rather than (or in addition to) the WHIM. However, we find no additional galaxies near a fourth "void" absorber recently found in the spectrum, suggesting that this system may indeed trace gas unassociated with any individual halo. Though the number of known systems is still small, spatial coincidences suggest that some X-ray absorbers lie in galaxy and/or group environments, though others could still trace the large-scale filamentary WHIM gas predicted by simulations.
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