• 천문학회보
• /
• 제41권2호
• /
• pp.57.1-57.1
• /
• 2016

Methanol ($CH_3OH$) is a key species in the formation of complex organic molecules. We report the first detection of solid $CH_3OH$ in a line of sight toward the Galactic center (GC) region, based on L-band spectra taken with the Subaru telescope, aided by L'-band imaging data and moderate-resolution spectra from NASA/IRTF. It is found toward a background star, ~8000 AU in projected distance from a newly discovered massive young stellar object (YSO). This YSO also exhibits a strong $CO_2$ ice absorption band at ${\sim}15{\mu}m$ in Spitzer/IRS data, which has a prominent long-wavelength wing. It confirms that a high $CH_3OH$ abundance is responsible for the broad $15{\mu}m$ $CO_2$ ice absorption towards massive YSOs in the GC. Clearly, $CH_3OH$ formation in ices is efficient in the GC region, as it is in star-forming regions in the Galactic disk. We discuss implications of our result on the astrochemical processes in the hostile GC molecular clouds.

• 천문학회보
• /
• 제44권2호
• /
• pp.49.2-49.2
• /
• 2019

We present results from our long-term observing campaign, using the NASA IRTF at Maunakea, to obtain 2 - 4 ㎛ spectra of 118 red point sources in the line of sight to the Galactic Center (GC). Our sample is largely composed of point sources selected from near- and mid-infrared photometry, but also includes a number of massive young stellar objects. Many of these sources show high foreground extinction as shown by deep 3.4 ㎛ aliphatic hydrocarbon absorption feature, which is a characteristic of the diffuse ISM and comes from the long line of sight through the diffuse medium toward the Central Molecular Zone (CMZ), the central 300 pc region of the GC. The deep 3.1 ㎛ H₂O ice absorption band coming from the local, dense material in the GC CMZ suggests that most sources are likely located in the GC CMZ. A few of these sources show weak CCH₃OH ice absorption at 3.535 ㎛, which can provide a strong constraint on the CCH₃OH ice formation in the unique environment of the CMZ. From the best-fitting models, the optical depths of these features are determined and used to generate a well-rounded view of the ice composition across the GC CMZ and the spectral characteristics of massive YSOs in the GC.

• 한국의학물리학회지:의학물리
• /
• 제28권1호
• /
• pp.16-21
• /
• 2017

This study assessed the feasibility of a dual-channel (DC) compound method for film dosimetry. The red channel (RC) is usually used to ensure dosimetric quality using a conventional fraction dose because the RC is more accurate at low doses within 3 Gy than is the green channel (GC). However, the RC is prone to rapid degradation of sensitivity at high doses, while degradation of the GC is slow. In this study, the DC compound method combining the RC and GC was explored as a means of providing accurate film dosimetry for high doses. The DC compound method was evaluated at various dose distributions using EBT3 film inserted in a solid-water phantom. Measurements with $10{\times}20cm^2$ radiation field and $60^{\circ}$ dynamic-wedge were done. Dose distributions acquired using the RC and GC were analyzed with root-mean-squares-error (RMSE) and gamma analyses. The DC compound method was used based on the RC after correcting the GC for high doses in the gamma analysis. The RC and GC produced comparatively more accurate RMSE values for low and high doses, respectively. Gamma passing rates with an acceptance criterion of 3%/3 mm revealed that the RC provided rapid reduction in the high dose region, while the GC displayed a gradual decrease. In the whole dose range, the DC compound method had the highest agreement (93%) compared with single channel method using either the RC (80%) or GC (85%). The findings indicate that the use of DC compound method is more appropriate in dosimetric quality assurance for radiotherapy using high doses.

• 미생물학회지
• /
• 제39권3호
• /
• pp.128-134
• /
• 2003

Transformation-associated recombination (TAR) 클로닝법은 목적 유전자를 포함한 게놈 DNA와 그 유전자의 5' 또는 3' 말단 서열을 포함하고 있는 선형의 TAR vector를 동시에 출아효모의 spheroplast내로 co-penetration 시켜 상동부위에서 일어나는 재조합에 의해 환형의 Yeast Artification Chromosome(YAC)으로 분리되는 방법이다. 일반적으로 TAR 클로닝법에 의한 목적의 single-copy 유전자 분리 빈도는 전체 형질전환체의 0.01~1% 정도이다. 이러한 TAR 클로닝법을 개선하기 위하여 Tg.AC transgenic mouse를 모델계로 사용하여 유전자 분리에 대한 target hook 내의 GC content 가 미치는 영향을 조사하였다. 이러한 목적으로 한쪽에는 다양한 GC content(18~45%)를 지닌 transgene 특이적 hook을 포함하고 다른 한쪽은 B1 반복서열을 가지는 radial TAR vector를 사용하여 transgene 분리 빈도를 측정하였다. 그 결과 target hook의 GC content는 23% 이하의 경우, ~40%인 경우에 비해 두 배 정도 클로닝 빈도가 감소하였다. 따라서 TAR vector를 제작할 때, 유전자 분리에 이용되는 target hook의 GC content는 약 40% 일때 가장 적정한 것으로 나타났다. 또한 높은 target hook 내의 GC content(65%)위치분포에 의한 차이는 클로닝 빈도에 큰 영향을 미치지 않는 것으로 나타났다.

• 천문학회보
• /
• 제36권1호
• /
• pp.83.2-83.2
• /
• 2011

I present results from the Spitzer/IRS study to identify massive young stellar objects (YSOs) in the Galactic Center (GC). Our sample of 107 YSO candidates was selected based on Spitzer/IRAC colors in the central 300 pc region of the Milky Way Galaxy. We obtained IRS spectra over $5{\mu}m$ to $35{\mu}m$, and identified massive YSOs by the presence of a $15.4{\mu}m$ shoulder on the absorption profile of $15{\mu}m$ $CO_2$ ice, suggestive of high $CH_3OH$ abundance on $CO_2$ ice grains. This $15.4{\mu}m$ shoulder is clearly observed in 16 sources and possibly observed in an additional 19 sources. We further show that 9 massive YSOs reveal molecular gas-phase absorption from $CO_2$, $C_2H_2$, and/or HCN, which traces warm and dense gas in YSOs. Our results provide the first spectroscopic census of the massive YSO population in the GC.

• Asian Pacific Journal of Cancer Prevention
• /
• 제13권4호
• /
• pp.1407-1412
• /
• 2012

Background & Objectives: Gastric cancer is a leading cause of cancer-related deaths in both sexes in Iran. This study was designed to assess upper GI endoscopic findings among people > 50 years targeted in a mass screening program in a hot-point region. Methods: Based on the pilot results in Guilan Cancer Registry study (GCRS), one of the high point regions for GC-Lashtenesha- was selected. The target population was called mainly using two methods: in rural regions, by house-house direct referral and in urban areas using public media. Upper GI endoscopy was performed by trained endoscopists. All participants underwent biopsies for rapid urea test (RUT) from the antrum and also further biopsies from five defined points of stomach for detection of precancerous lesions. In cases of visible gross lesions, more diagnostic biopsies were taken and submitted for histopathologic evaluation. Results: Of 1,394 initial participants, finally 1,382 persons (702 women, 680 men) with a mean age of $61.7{\pm}9.0$ years (range: 50-87 years) underwent upper GI endoscopy. H. pylori infection based on the RUT was positive in 66.6%. Gastric adenocarcinoma and squamous cell carcinoma of esophagus were detected in seven (0.5%) and one (0.07%) persons, respectively. A remarkable proportion of studied participants were found to have esophageal hiatal hernia (38.4%). Asymptomatic gastric masses found in 1.1% (15) of cases which were mostly located in antrum (33.3%), cardia (20.0%) and prepyloric area (20.0%). Gastric and duodenal ulcers were found in 5.9% (82) and 6.9% (96) of the screened population. Conclusion: Upper endoscopy screening is an effective technique for early detection of GC especially in high risk populations. Further studies are required to evaluate cost effectiveness, cost benefit and mortality and morbidity of this method among high and moderate risk population before recommending this method for the GC surveillance program at the national level.

• 대한환경공학회지
• /
• 제32권3호
• /
• pp.227-233
• /
• 2010

각종 오염지역의 오염토양의 시료를 채취해 DGGE를 이용한 미생물군집구조를 서로 비교함으로써 어떤 요인이 영향을 많이 미치는지를 알아보았다. 미생물군집의 유사도 비교에서 TPH 오염 말고는 대부분의 오염정도가 심하지 않아서 오염 특성보다는 토양시료가 채취된 지역에 따라 더 유사함을 보여주었고 TPH 오염도가 가장 높았던 시료에서만 지역적 특성을 넘어 유사도 차이를 보여 주었다. 이와 같이 오염요인이 너무 크지 않은 경우에는 미생물군집구조가 지역특성 즉 여러 다른 환경요인에 의해 더 크게 영향을 받는 것을 이 연구를 통해 알 수가 있었다. 모든 오염토양의 우점종(배양성 세균) 조사에서 firmicutes와 high GC Gram+에 속하는 세균들이 주로 발견되었고 유류오염이 심한 토양에서 이미 보고된 Arthrobacter, Bacillus, Methylobacterium, Clavibacter, Streptomyces, Nocardia와 아직 보고되지 않은 Leifsonia가 발견되었다.

• BMB Reports
• /
• 제37권6호
• /
• pp.700-708
• /
• 2004

The genes located within the p74 gene region of the Choristoneura fumiferana granulovirus (ChfuGV) were identified by sequencing an 8.9 kb BamHI restriction fragment on the ChfuGV genome. The global guanine-cytosine (GC) content of this region of the genome was 33.02%. This paper presents the ORFs within the p74 gene region along with their transcriptional orientations. This region contains a total of 15 open reading frames (ORFs). Among those, 8 ORFs were found to be homologues to the baculoviral ORFs: Cf-i-p , Cf-vi, Cf-vii, Cf-viii (ubiquitin), Cf-xi (pp31), Cf-xii (lef-11), Cf-xiii (sod) and Cf-xv-p (p74). To date, no specific function has been assigned to the ORFs: Cf-i, Cf-ii, Cf-iii, Cf-iv, Cf-v, Cf-vi, Cf-vii, Cf-ix and Cf-x. The most noticeable ORFs located in this region of the ChfuGV genome were ubiquitin, lef-11, sod, fibrillin and p74. The phylogenetic trees (constructed using conceptual products of major conserved ORFs) and gene arrangement in this region were used to further examine the classification of the members of the granulovirus genus. Comparative studies demonstrated that ChfuGV along with the Cydia pomonella granulovirus (CpGV), Phthorimaea operculella granulovirus (PhopGV), Adoxophyes orana granulovirus (AoGV) and Cryptophlebia leucotreta granulovirus (ClGV) share a high degree of amino acids sequence and gene arrangement preservation within the studied region. These results support a previous report, which classified a granuloviruses into 2 distinct groups: Group I: ChfuGV, CpGV, PhopGV and AoGV and Group II: Xestia c-nigrum granulovirus (XcGV) and Plutella xylostella granulovirus (PxGV). The phylogenetic and gene arrangement studies also placed ClGV as a novel member of the Group I granuloviruses.

• 천문학회보
• /
• 제39권1호
• /
• pp.45.2-45.2
• /
• 2014

We carry out the first survey for globular clusters (GCs) of three galaxies in cosmic voids using Hubble Space Telescope (HST) Advanced Camera for Survey archival F606W and F814W images. While all sample galaxies are classified as early-type galaxies based on ground-based imaging, the high resolution HST images reveal that they are actually spiral galaxies. We identify the point sources with red colors typical for GCs as GC candidates in the color-magnitude diagrams. As a result, we find a significant number of GC candidates. The spatial and radial distribution of GCs show central concentration on each galaxy region. Their mean colors are similar to that of the Milky Way and M31 GCs. The void GCs are somewhat bluer by, and than cluster and field GCs in early-type galaxies with similar luminosity to our samples, but the discrepancy is not significant. We also estimate the specific frequencies of GCs in these galaxies and the values are consistent with those in field and cluster galaxies with similar luminosity. From these results, we suggest that the formation process of void GCs is similar to that of GCs in other environments. The further implications will be discussed.

• 한국자원식물학회:학술대회논문집
• /
• 한국자원식물학회 2018년도 춘계학술발표회
• /
• pp.40-40
• /
• 2018

Pseudostellaria Pax (Caryophyllaceae) is a small genus distributed in temperate region. It consists of 25 species presenting high diversity in Asia. Pseudostellaria longipedicellata S. Lee, K. Heo & S. C. Kim was first announced as new species in 2012. Morphological characters of P. longipedicellata are closely related to those of Psedusotellaria palibiniana and Psedusotellaria okmotoi. These are distinguished from P. longipedicellata by shorter pedicel and puberulent pedicels, respectively and by being distributed allopatically between P. longipedicellata and rest of species. The complete chloroplast genome of P. longipedicellata was successfully rescued from raw reads generated by HiSeq2000. Its total length is 149,626 bp consisting of four regions: large single copy (LSC) region (81,292 bp), small single copy (SSC) region (16,984bp), and inverted repeats (IRs; 25,765 bp per each). It contained 126 genes (81 coding DNA sequence (CDS), eight rRNAs, and 37 tRNAs); 18 genes (seven CDS, four rRNAs, and seven tRNAs) are duplicated in inverted repeat regions. The overall GC content of P. longipedicellata is 36.5% and in the LSC, SSC, and IR regions were 34.3%, 29.3%, and 42.4%, respectively. Based on phylogenetic analysis of chloroplast genomes of P. longipedicellata and relatives species presents clear phylogenetic positions of Pseudostellaria genus. This chloroplast genome will be an important sequence resources for further researches of Pseudostellaria genus.