• 천문학회보
• /
• 제35권2호
• /
• pp.73.2-73.2
• /
• 2010

In order to understand internal dynamics of starless cores, molecular line emissions are usually observed. From profiles of the molecular lines, internal motions of starless cores have been deduced using a simple radiative transfer model such as the two-layer model (Myers et al.1996). This brings complexities arising from the chemical evolution. The motivation of this study is to follow the chemical evolution of a starless core that goes through gravitational contraction. For this purpose, we have performed hydrodynamical simulations with a marginally unstable Bonnor-Ebert sphere as an initial condition. We follow the chemical evolution of this core with changing conditions such as the chemical reaction rate at the dust surface and the strength of radiation field that penetrate into the core. At the core center, the molecules suffer from a higher degree of molecular depletion on the dust covered by ice rather than on the bare silicate dust. The stronger radiation field dissociates more molecules at the core envelope. From analysis on the line profile using the two-layer model, we found that the speed of inward motion deduced from the HCN F = 2-1 line adequately traces the true infall speed, when the dust is covered by ice and the core is exposed to the diffuse interstellar radiation field. Under different conditions, the two-layer model significantly underestimate the infall speed.

• Molecular & Cellular Toxicology
• /
• 제2권1호
• /
• pp.60-66
• /
• 2006

Methylmercury (MeHg), one of the heavy metal compounds, can cause severe damage to the central nervous system in humans. Many reports have shown that MeHg is poisonous to human body through contaminated foods and has released into the environment. Despite many studies on the pathogenesis of MeHg-induced central neuropathy, no useful mechanism of toxicity has been established so far. This study, using of suppression subtractive hybridization (SSH) method, was peformed to identify differentially expressed genes by MeHg in SH-SY5Y human neuroblastoma cell line. We prepared to total RNA from SH-SY5Y cells treated with solvent (DMSO) and $6.25\;{\mu}M\;(IC_{50})$ MeHg and performed forward and reverse SSH. Differentially expressed cDNA clones were screened by dot blot, sequenced and confirmed that individual clones indeed represent differentially expressed genes with real time RT-PCR. These sequences were identified by BLAST homology search to known genes or expressed sequence tags (ESTs). Analysis of these sequences may provide an insight into the biological effects of MeHg in the pathogenesis of neurodegenerative disease and a possibility to develop more efficient and exact monitoring system of heavy metals as ubiquitous environmental pollutants.

• 천문학회보
• /
• 제44권2호
• /
• pp.48.1-48.1
• /
• 2019

We found a diffuse Hα feature with a large size of ~2' around a Herbig star, MWC 1080. It shows a strong correlation with the elongated outflow cavity centered on the star. To investigate the diffuse Hα source and the molecular cavity in detail, we carried out the high-resolution NIR spectroscopy using IGRINS. We detected six hydrogen Brackett line series, seven H2 lines, and an [Fe II] forbidden line. With the obtained spatial, kinematic, and line ratio results, we discuss the characteristics of the central MWC 1080A, the NE outflow cavity, and the SE molecular cloud regions separately. Most of the bright Brγ sources around MWC 1080A were found to be reflection nebulae, but a point-like Brγ source close to another young star, MWC 1080E, was identified as a distinct source due to MWC 1080E itself. The narrow components of the H2 lines observed around MWC 1080A were found to trace PDRs located on the wall of the main outflow cavity. Based on the shock-excited H2 and [Fe II] lines detected just inside a bow-shock shape Hα feature, we suggest that it represents the actual shock at the head of the NE outflow from MWC 1080A. Also, we newly detected the shock-excited H2 and [Fe II] lines with highly blueshifted velocities in the SE molecular cloud region. They could be related to unrevealed outflows from other young stars existing around MWC 1080A.

• Journal of Animal Science and Technology
• /
• 제66권5호
• /
• pp.1010-1020
• /
• 2024

Deoxynivalenol (DON) is the most common mycotoxin contaminant of food or feed worldwide and causes disease in animals. Lauric acid (LA) is a medium-chain fatty acid useful for barrier functions such as antimicrobial activity in the intestine of monogastric animals. However, the molecular mechanisms by which lauric acid exerts its effects on the deoxynivalenol-exposed small intestine have not been studied. We used an intestinal porcine epithelial cell line (IPEC-J2) as an in vitro model to explore the molecular mechanism of lauric acid in alleviating deoxynivalenol-induced damage. We found that lauric acid reversed deoxynivalenol-induced reduction in cell viability. Our quantitative real-time polymerase chain reaction results indicated that lauric acid alleviated deoxynivalenol-induced apoptosis through Annexin-V. Additionally, immunofluorescence and Western blotting showed that lauric acid attenuated deoxynivalenol-induced forkhead box O3 (FOXO3a) translocation into the nucleus. These results suggest that lauric acid attenuates forkhead box O3 translocation in the small intestine damaged by deoxynivalenol, thereby reducing apoptosis. In conclusion, this study found that lauric acid alleviates deoxynivalenol-induced damage in intestinal porcine epithelial cell line through various molecular mechanisms.

• 천문학회보
• /
• 제36권2호
• /
• pp.106.2-106.2
• /
• 2011

The two competing theories of star formation are based on turbulence and ambipoar diffusion. I will first briefly explain the two theories. There have been analytical (or semi-analytic) models, which estimate star formation rates in a turbulent cloud. Most of them are based on the log-normal density PDF (probability density function) of the turbulent cloud without self-gravity. I will first show that the core (star) formation rate can be increased significantly once self-gravity of a turbulence cloud is taken into account. I will then present the evolution of molecular line profiles of HCO+ and C18O toward a dense core that is forming inside a magnetized turbulent molecular cloud. Features of the profiles can be affected more significantly by coupled velocity and abundance structures in the outer region than those in the inner dense part of the core. During the evolution of the core, the asymmetry of line profiles easily changes from blue to red, and vice versa. Finally, I will introduce a method for incorporating ambipolar diffusion in the strong coupling approximation into a multidimensional magnetohydrodynamic code.

• Bulletin of the Korean Chemical Society
• /
• 제13권5호
• /
• pp.553-556
• /
• 1992

The ${CO}_2$ laser absorption measurement of ${CH}_3{CH}_2Br$ utilizing photoacoustic (PA) technique was performed using a cw and a pulsed ${CO}_2$ lasers. The absorption profile in the ${CO}_2$ laser wavelength region (9-10 ${\mu}$m) and the macroscopic small signal absorption cross section at 10P(20) (10.59 ${\mu}$m, 944 $cm^{-1}$) laser line were measured using a cw ${CO}_2$ laser. The laser fluence dependence on infrared multiphoton absorption (IRMPA) was also studied with a pulsed TEA ${CO}_2$ laser at 10P(20) laser line. In view of monotonic increase of PA signal with the rise of laser fluence, it was suggested that the anharmonicity in pumped vibration mode did not restrict ir multiphoton absorption in ${CH}_3{CH}_2Br$ system as found in large molecular system.

• Molecular & Cellular Toxicology
• /
• 제5권1호
• /
• pp.67-74
• /
• 2009

Exposures to environmental chemicals that mimic endogenous hormones are proposed for a number of adverse health effects, including infertility, abnormal prenatal and childhood development and above all cancers. In addition, recently miRNA (micro RNA) has been recognized to play an important role in various diseases and in cellular and molecular responses to toxicants. In this study, endocrine disrupting environmental toxicant, nonylphenol (NP) was treated to MCF-7 (Human breast cancer cell) and HepG2 (Human hepatocellular liver carcinoma) cell line at 3 hrs and 48 hrs time point and miRNA analysis using $mirVana^{TM}$ miRNA bioarray was performed and compared with total mRNA microarray data for the same cell line and treatment. Robust data quality was achieved through the use of dye-swap. Analysis of microarray data identifies a total of 20 and 11 miRNA expressions at 3 hrs and 48 hrs exposure to NP in MCF-7 cell line and a total of 14 and 47 miRNA expression at 3 hrs and 48 hrs exposure respectively to NP in HepG2 cell line. Expression profiling of the selected miRNA (let-7c, miR-16, miR-195, miR-200b, miR200c, miR-205, and miR-589) reveals changes in the expression of target genes related to metabolism, immune response, apoptosis, and cell differentiation. The present study can be informative and helpful to understand the role of miRNA in molecular mechanism of chemical toxicity and their influence on hormone dependent disease. Also this study may prove to be a valuable tool for screening potential estrogen mimicking pollutants in the environment.

• Molecules and Cells
• /
• 제26권3호
• /
• pp.243-249
• /
• 2008

Corticotropin releasing factor (CRF) mediates various responses to stress through CRF receptors 1 and 2. CRF receptor 2 has two forms, $2{\alpha}$ and $2{\beta}$ each of which appears to have distinct roles. Here we used dopaminergic neuron-derived MN9D cells to investigate the function of CRF receptor 2 in dopamine neurons. We found that n-butyrate, a histone deacetylase inhibitor, induced MN9D cell differentiation and increased gene expression of all CRF receptors. CRF receptor $2{\beta}$ was minimally expressed in MN9D cells; however, its expression dramatically increased during differentiation. CRF receptor $2{\beta}$ expression levels appeared to correlate with neurite outgrowth, suggesting CRF receptor $2{\beta}$ involvement in neuronal differentiation. To validate this statement, we made a CRF receptor $2{\beta}$-overexpressing $MN9D/CRFR2{\beta}$ stable cell line. This cell line showed robust neurite outgrowth and GAP43 overexpression, together with MEK and ERK activation, suggesting MN9D cell neuronal differentiation. From these results, we conclude that CRF receptor $2{\beta}$ plays an important role in MN9D cell differentiation by activating the MEK/ERK signaling pathway.

• Journal of Microbiology and Biotechnology
• /
• 제27권3호
• /
• pp.561-572
• /
• 2017

The global commercial cultivation of transgenic crops, including glyphosate-tolerant soybean, has increased widely in recent decades with potential impact on the environment. The bulk of previous studies showed different results on the effects of the release of transgenic plants on the soil microbial community, especially rhizosphere bacteria. In this study, comparative analyses of the bacterial communities in the rhizosphere soils and surrounding soils were performed between the glyphosate-tolerant soybean line NZL06-698 (or simply N698), containing a glyphosate-insensitive EPSPS gene, and its control cultivar Mengdou12 (or simply MD12), by a 16S ribosomal RNA gene (16S rDNA) amplicon sequencing-based Illumina MiSeq platform. No statistically significant difference was found in the overall alpha diversity of the rhizosphere bacterial communities, although the species richness and evenness of the bacteria increased in the rhizosphere of N698 compared with that of MD12. Some influence on phylogenetic diversity of the rhizosphere bacterial communities was found between N698 and MD12 by beta diversity analysis based on weighted UniFrac distance. Furthermore, the relative abundances of part rhizosphere bacterial phyla and genera, which included some nitrogen-fixing bacteria, were significantly different between N698 and MD12. Our present results indicate some impact of the glyphosate-tolerant soybean line N698 on the phylogenetic diversity of rhizosphere bacterial communities together with a significant difference in the relative abundances of part rhizosphere bacteria at different classification levels as compared with its control cultivar MD12, when a comparative analysis of surrounding soils between N698 and MD12 was used as a systematic contrast study.

• 천문학회보
• /
• 제30권1호
• /
• pp.31.1-31.1
• /
• 2005