• Title/Summary/Keyword: H II region

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Chemical properties of cores in different environments; the Orion A, B and λ Orionis clouds

  • Yi, Hee-Weon;Lee, Jeong-Eun;Tie, Liu;Kim, Kee-Tae
    • The Bulletin of The Korean Astronomical Society
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    • v.42 no.2
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    • pp.80.1-80.1
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    • 2017
  • We present preliminary results of KVN single dish telescope observations of 80 dense cores in the Orion molecular cloud complex which contains the Orion A, B, and ${\lambda}$ Orionis cloud. We investigate the behavior of the different molecular tracers and look for chemical variations of cores in the three clouds in order to systematically investigate the effects of stellar feedback. The most commonly detected molecular lines (with the detection rates higher than 50%) are N2H+, HCO+, H13CO+, C2H, HCN, and H2CO. The detection rates of dense gas tracers, N2H+, HCO+, H13CO+, and C2H show the lowest values in the ${\lambda}$ Orionis cloud. We find difference between molecular D/H ratios and N2H+/H13CO+ abundance ratios towards different clouds, and between protostellar cores and starless cores. Eight starless cores in the Orion A and B clouds exhibit high deuterium fractionations, larger than 0.10, while in the ${\lambda}$ Orionis cloud, no cores reveal the high ratio. These chemical properties could support that cores in the ${\lambda}$ Orionis cloud are affected by the photo-dissociation and external heating from the nearby H II region, which is a hint of negative stellar feedback on core formation. The striking difference between the [N2H+]/[H13CO+] ratios leads us to suggest that there are significant evolutionary differences between the Orion A/B and ${\lambda}$ Orionis clouds. In order to examine whether starless cores can be candidates of pre-stellar cores, we compared the core masses estimated from the 850 um emission to their Virial masses calculated from the N2H+ line data and find that most of them are not gravitationally bound in the three clouds.

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Partial Sequence of the Bovine (Bos taurus coreanae) Myogenic Factor Encoding Gene MyoD

  • Kim, H.S.;Park, E.W.;Yoon, D.H.;Kim, H.B.;Cheong, I.C.;Cho, B.W.;Im, K.S.
    • Asian-Australasian Journal of Animal Sciences
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    • v.12 no.5
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    • pp.689-694
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    • 1999
  • This experiment was carried out to isolate the partial bovine (Bos Taurus coreanae) myogenic factor encoding gene, MyoD, using the rat myogenic factor (MyoD) gene sequence and to compare the gene sequence between another myogenic factor (Myf 5) and MyoD gene of the bovine. To make the probe and isolate the MyoD gene, PCR was performed to amplify rat and bovine MyoD gene including exon I, II and intron I. The homology between mouse and bovine MyoD is high; bovine MyoD gene shows 17 different gene sequence region compared to rat MyoD. Among those, two regions have significant differences; one is the exon I part between 2834 and 2850 bp, the other is intron part between 3274 and 3303 bp of the mouse. At this region homology was 40% in the former and 50% in the latter. Homology between bovine MyoD and Myf5 was 83% in the exon 1. Especially exon I in the Myf5 602-617 bp and 651-683 bp have significant differences. These results suggest that MyoD gene have a similar gene structure in mouse and bovine and MyoD and Myf5 of the bovine, at least in part, have a similar expression and activity.

MIRIS Paschen-α Galactic Plane Survey : Comparison with WISE catalog and IPHAS Hα data in Cepheus

  • Kim, Il-Joong;Pyo, Jeonghyun;Jeong, Woong-Seob;Kim, Min Gyu;Lee, Dukhang;Park, Won-Kee;Park, Sung-Joon;Moon, Bongkon;Park, Youngsik;Lee, Dae-Hee;Han, Wonyong
    • The Bulletin of The Korean Astronomical Society
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    • v.42 no.1
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    • pp.39.3-39.3
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    • 2017
  • To see scientific potential of MIRIS Paschen-${\alpha}$ ($Pa{\alpha}$) Galactic Plane Survey (MIPAPS), we have selected a portion, Galactic longitude from $+96^{\circ}$ to $116^{\circ}$, and inspected $Pa{\alpha}$ detections for 212 sources in WISE H II region catalog. We also list up $35Pa{\alpha}$ large features and $32Pa{\alpha}$ point-like blobs, which have not been cataloged in WISE catalog. For all the sources, we have performed the photometry of $Pa{\alpha}$ emission line, and obtained their $Pa{\alpha}$ intensities and $Pa{\alpha}$ fluxes. For the quantitative comparison, we also make the $H{\alpha}$ mosaic image of the same region by using IPHAS data which have been globally calibrated and released recently. Comparing MIPAPS $Pa{\alpha}$ fluxes with the IPHAS $H{\alpha}$ fluxes enables us to estimate dust extinction and spectral types of ionizing sources. We present the results for some sources.

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Effect of AC Electric Field on Decreasing Liftoff Height in Laminar Lifted Jet Flames (층류 부상 화염의 화염부상 높이 감소 구간에서 교류 전기장이 인가된 화염에 관한 영향)

  • Seo, B.H.;Van, K.H.;Kim, G.T.;Park, J.;Keel, S.I.;Kim, S.W.;Chung, S.H.
    • Journal of the Korean Society of Combustion
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    • v.22 no.3
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    • pp.17-22
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    • 2017
  • An experimental study has been conducted to elucidate the effect of AC electric field on behaviors of laminar lifted flame in nitrogen-diluted methane coflow-jets. Our concerns are focued on the regime to show a decrease in liftoff height, $H_L$ with increasing nozzle exit velocity, $U_O$ (hereafter, $decreasing-H_L$). The $H_L$ with $U_O$ near flame extinction were measured by varying the applied AC voltage, $V_{AC}$ and frequency, $f_{AC}$ in a single electrode configuration. The behavior of $H_L$ with a functional dependency of $V_{AC}$ and $f_{AC}$ was categorized into two regime : (I) $H_L$ decreased for nozzle diameter, D = 1.0 mm, and (II) $H_L$ increased in the increase of $f_{AC}$ for a fixed $V_{AC}$ in a D = 4.0, 8.4 mm. The lifted flames in $decreasing-H_L$ region was unstable in high voltage regimes while the $H_L$ showed a decreasing tendency with $U_O$ except them. Such behaviors in $H_L$ were also characterized by functional dependencies of related physical parameters such as $V_{AC}$, $f_{AC}$, $U_O$, fuel mole fraction ($X_{F.O}$) and D.

Comparison of the Binding Modes of [Ru(2,2'-bipyridine)3]2+ and [Ru(2,2':6',2"-terpyridine)2]2+ to Native DNA

  • Jang, Yoon-Jung;Lee, Hyun-Mee;Jang, Kyeung-Joo;Lee, Jae-Cheol;Kim, Seog-K.;Cho, Tae-Sub
    • Bulletin of the Korean Chemical Society
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    • v.31 no.5
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    • pp.1314-1318
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    • 2010
  • The $[Ru(tpy)_2]Cl_2$ (tpy:2,2':6',2"-terpyridine) complex was synthesized and its structure was confirmed by $^1H$-NMR and elemental analysis. Its binding mode toward DNA was compared with the well-known $[Ru(bpy)_3]Cl_2$ (bpy:2,2-bipyridyl), using isotropic absorption, linear dichroism(LD) spectroscopy, and an energy minimization study. Compared to $[Ru(bpy)_3]^{2+}$, the $[Ru(tpy)_2]^{2+}$ complex exhibited very little change in its absorption pattern, especially in the MLCT band, upon binding to DNA. Furthermore, upon DNA binding, both Ru(II) complexes induced a decrease in the LD magnitude in the DNA absorption region. The $[Ru(tpy)_2]^{2+}$ complex produced a strong positive LD signal in the ligand absorption region, which is in contrast with the $[Ru(bpy)_3]^{2+}$ complex. Observed spectral properties led to the conclusion that the interaction between the ligands and DNA bases is negligible for the $[Ru(tpy)_2]^{2+}$ complex, although it formed an adduct with DNA. This conclusion implies that both complexes bind to the surface of DNA, most likely to negatively charged phosphate groups via a simple electrostatic interaction, thereby orienting to exhibit the LD signal. The energy minimization calculation also supported this conclusion.

Safety Analysis of Adjuvant Chemotherapy with Docetaxel Administered with or without Anthracyclines to Early Stage Breast Cancer Patients: Combined Results from the Asia-Pacific Breast Initiatives I and II

  • Kim, Sung Bae;Sayeed, Ahmed;Villalon, Antonio H;Shen, Zhen Zhou;Yau, Tsz Kok;Shah, Mazhar Ali;Hou, Meng Feng;Thuan, Tran Van;Ba, Duc Nguyen;Chao, Tsu-Yi
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.2
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    • pp.697-702
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    • 2016
  • Background: The Asia-Pacific Breast Initiatives (APBI) I and II registries were established to collect safety data for patients with early stage breast cancer receiving adjuvant docetaxel-based regimens in the Asia-Pacific region. Materials and Methods: Data from the two registries were combined to perform a safety analysis. Participants in the registry were women with early stage operable breast cancer with an intermediate or high risk of recurrence. These women received adjuvant chemotherapy that included docetaxel between 2006 and 2011. Adverse events (AEs) were recorded and analyzed. Results: Data were collected from 3,224 patients from 13 countries. The mean dose intensity of docetaxel was 24.1, 22.7, $25.1mg/m^2/week$ among patients receiving docetaxel-based monotherapy, combination therapy and sequential therapy, respectively. Granulocyte colony-stimulating factor (G-CSF) was given with docetaxel to 41.8% of women and 20.6% of women receiving prophylactic antibiotics. Adverse events were reported in 86% of patients (anthracycline-containing regimens vs. non-anthracycline regimens; 87% vs. 80%). The most common adverse events were alopecia, nausea, neutropenia, vomiting, and myalgia. Adverse events NCI CTCAE ${\geq}$Grade 3 were reported in 45.4% of patients. Serious adverse events were reported in 13% of patients, of which 2.5% led to study discontinuation. Forty-six deaths (1.4%) were reported, with no significant difference between regimens. Conclusions: The safety parameters of adjuvant docetaxel therapy used to treat sequential Asian women were comparable to those reported in clinical trials evaluating the role of adjuvant docetaxel. No unusual adverse events linked to Asia-Pacific region patients were observed.

Ionized Fe Objects in UWIFE survey and IGRINS

  • Kim, Yesol;Koo, Bon-Chul;Pyo, Tae-Soo
    • The Bulletin of The Korean Astronomical Society
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    • v.42 no.1
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    • pp.54.1-54.1
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    • 2017
  • The UKIRT Wide-field Infrared survey for Fe+(UWIFE) is an unbiased survey of the first Galactic quadrant, with narrow-band filter centered on $1.644{\mu}m$. This survey covers $7^{\circ}$ < l < $62^{\circ}$ and |b| < $1.5^{\circ}$, where active interaction of stars and interstellar medium is expected. With median seeing of 0.8 arcsec, 5 - sigma detection limit of 18.7 mag and surface brightness limit of $8.1{\times}10^{-20}W\;m^{-2}arcsec^{-2}$, this survey gives an opportunity to statistically study Galactic [Fe II] - emitting sources for the first time. In order to identify Ionized Fe Objects (IFOs) in survey area systematically, we conducted visual inspection and automatic detection simultaneously. Total of ~300 extended IFOs are identified, most of them are found out to be part of supernova remnants (SNRs), young stellar objects, HII regions and planetary nebulae. The majority of IFOs are new discoveries which reveal shocked structures in high-extinction region. Spatial distribution of IFOs suggest that they trace Galactic structure. As a part of spectroscopic follow-up, we observed SNR candidate IFO J183740.829-061452.41 with IGRINS (Immersion Grating Infrared Spectrograph, Yuk+2010), mounted on 2.7m Harlan Smith telescope. This unknown arc-like, 6'-long IFO is coincident with inner part of radio continuum loop G25.8+0.2, which has been known as HII region. However, interior of this radio shell is filled with diffuse soft X-ray emission, and possible association of hard X-ray pulsar / pulsar wind nebula makes the nature of the IFO unclear. The H and K-band 2D spectrum shows shock-ionized [Fe II] filaments, which is apart from photoionized HII filaments. In this presentation we present basic statistics of newly identified IFOs, as well as the follow-up study of IFO J183740.829-061452.41.

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Backbone NMR assignments of the anti-CRISPR AcrIIA5 from phages infecting Streptococcus thermophilus

  • An, So Young;Kim, Eun-Hee;Bae, Euiyoung;Suh, Jeong-Yong
    • Journal of the Korean Magnetic Resonance Society
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    • v.24 no.3
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    • pp.70-76
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    • 2020
  • The CRISPR-Cas system provides an adaptive immunity for bacteria and archaea against invading phages or foreign plasmids. In the type II CRISPR-Cas system, a single effector protein Cas9 and a guide RNA form an RNA-guided endonuclease complex that can degrade DNA targets of foreign origin. To avoid the Cas9-mediated destruction, phages evolved anti-CRISPR (Acr) proteins that neutralize the host bacterial immunity by inactivating the CRISPR-Cas system. Here we report the backbone 1H, 15N, and 13C resonance assignments of AcrIIA5 that inhibits the endonuclease activity of type II-A Streptococcus thermophilus Cas9 and also Streptococcus pyogenesis Cas9 using triple resonance nuclear magnetic resonance spectroscopy. The backbone chemical shifts of AcrIIA5 predict a disordered region at the N-terminus, followed by an αββββαβββ fold.

The Most Massive Active Galactic Nuclei at 1

  • Jun, Hyunsung
    • The Bulletin of The Korean Astronomical Society
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    • v.42 no.2
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    • pp.44.2-44.2
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    • 2017
  • We obtained near-infrared spectra of 26 SDSS quasars at 0.7${\sim}10^{{\wedge}{10}}M{\odot}$ to critically examine the systematic effects involved with their mass estimations. We find that active galactic nuclei (AGNs) heavier than $10^{{\wedge}{10}}M{\odot}$ often display double-peaked $H{\alpha}$ emission, extremely broad FeII complex emission around MgII, and highly blueshifted and broadened CIV emission. The weight of this evidence, combined with previous studies, cautions against the use of MBH values based on any emission line with a width over 8000 km/s. Also, the MBH estimations are not positively biased along the presence of ionized narrow line outflows, anisotropic radiation, or the use of line FWHM instead of ${\sigma}$ for our sample, and unbiased with variability, scatter in broad line equivalent width, or obscuration for general type-1 quasars. Removing the systematically uncertain MBH values, ${\sim}10^{{\wedge}{10}}M{\odot}$ BHs in 1${\sim}10^{{\wedge}{9.5}}M{\odot}$ BHs, although current observations support they are intrinsically most massive, and overmassive to the host's bulge mass.

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A Study on the Multi-Channel Active Noise Control for Noise Reduction of the Vehicle Cabin II : Semi-experiment (자동차 실내 소음저감을 위한 다채널 능동소음 제어에 관한 연구 II : 모의 실험)

  • Kim, H.S.;Lee, T.Y.;Shin, J.;Oh, J.E.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.2 no.6
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    • pp.29-37
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    • 1994
  • Active noise control of random noise which propatate in the vehicle cabin as a form of spherical wave is the target of this study. In the previous study, the adaptive algorithm for adaptive controller is presented for the application in active noise control system. And for the preliminary study of adaptive active noise control in vehicle cabin as a real system, a computer simulation is performed on the effectiveness of the adaptive algorithm in the amplitude of the pressure fluctuation. This work studies the implementation of multi-channel feedforward adaptive algorithm for the reduction of the noise inside a vehicle cabin using a number of secondary sources derived by adaptive filtering of reference noise source. Multi-channel adaptive feedforward algorithm are verified in numerical simulation and semi-experimental justification of developed system is made on a domestic passenger car. In the results of semi-experimental study, the noise of specific region in the interior of automobile are reduced for the appreciabe sound pressure level in the operating engine rpm and finally this study suggests the capabilities of the real time active noise control in 3 dimensional acoustic fields.

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