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KAMEYA, O.,TSUBOI, M.,ASAKI, Y.,YONEKURA, Y.,MIYAMOTO, Y.,KANEKO, H.,SETA, M.,NAKAI, N.,MIYOSHI, M.,TAKABA, H.,WAKAMATSU, K.,FUKUZAKI, Y.,MORIMITSU, T.,SEKIDO, M. The Korean Astronomical Society 2015 天文學論叢 Vol.30 No.2
We have been performing daily VLBI monitoring of the flux density of Sagittarius (Sgr) $A^{\ast}$ at 22 GHz from February 2013 to August 2014 using a sub-array of the Japanese VLBI Network (JVN). The purpose of this monitoring is to explore the flux density variability at daily time resolution for a period longer than one year with the G2 cloud approaching. The flux density of Sgr $A^{\ast}$ is basically stable during the observational period, though there are some small variations. The average and scattering range are consistent with the previously observed values. We have observed no strong flare of Sgr $A^{\ast}$ although it is near the expected peri-center passing.
A CYANOACETYLENE STUDY OF THE MOLECULAR DISK IN STAR FORMING REGIONS
Chung, H.S.,Kameya, Osamu,Morimoto, Masaki The Korean Astronomical Society 1991 Journal of The Korean Astronomical Society Vol.24 No.2
We have observed dense core around young stellar objects, DR21, S140, Orion-KL, and L1551 using four millimeter-wave transitions of $HC_3N\;J$=4-3, J=5-4, J=10-9, and J=12-11. The spatial distribution of $HC_3N$ emission closely resembles the morphology of the previous CS observations that trace high density gas. These observations reveal the existence of $HC_3N$ dense cores around central IR source, elliptical in shape and almost perpendicular to the CO bipolar outflow axis. Small differences can be explained by that $HC_3N$ molecular line is more optically thin and is seen to be more detailed structure in the neighborhood of central IR sources. In S140 and Orion-KL, massive(${\sim}10\;M_{\odot}$), slowly rotating dense cores lie near at the central IR sources of bipolar outflows. The velocity channel maps of DR21 show that the bipolar outflow gas may have a correlation with the dense core of DR21. We analyzed intensities of the four lines to derive physical conditions in dense core from two methods, LTE and LVG. The column density of $HC_3N$, $N(HC_3N)$, between LTE and LVG calculations agree well with each other. The abundances of $HC_3N$ in each observing source have been estimated using the average values of $n(H_2)$ and $N(HC_3N)$ and assuming the size of dense core. The fractional $HC_3N$ abundances in massive dense cores of DR21, S140, and Orion-KL have a range of $(2-7){\times}10^{-10}$, while that of low mass dense core, L1551, has one order of magnitude greater value of $2{\times}10^{-9}$. This should be considered good agreement with the result by Morris et al.(1976). It may be considered that dense cores of DR21, S140, and Orion-KL may have almost same stage of chemical evolution, and their abundances have a small values relative to that of L1551. The column density $N(HC_3N)$ decreases with increasing distance from the densest part of the cloud, the central infrared source, and have the relation of $N(HC_3N){\varpropto}R^{\alpha}$, where a has a range of 0.65 to 0.89. The values of $n(H_2)$ are not varied with increasing distance from the dense core, and have almost same values. Therefore, it is considered that the dense cores in these regions probably consist of dense clumps in diffuse molecular gas medium, and $n(H_2)$ of each clump is ${\sim}10^5\;cm^{-3}$. Levels in the $T_{ex}$ increases with $n(H_2)$. It is considered that the $HC_3N$ dense cores are not completely thermalized. We examine the relationships between the luminosity of central infrared sources versus mass of the dense cores, and the luminosity of central infrared sources versus molecular hydrogen column density. Luminosities of the central IR sources show good correlation with mass and hydrogen column density of the dense core. Same has been found from CS observations. However, mass and size derived from $HC_3N$ observations are one order of magnitude smaller than those from CS. It can be interpreted that we see more central part of the cloud cores in $NC_3N$ lines than CS lines.
수분ㆍ수정 시기를 이용한 Bialaphos 저항성 형질전환 담배의 개발
이효연,노일섭,김진호,유장렬,이종석,김학진,Toshiaki KAMEYA 한국식물생명공학회 1994 식물생명공학회지 Vol.21 No.2
비선택성 제초제인 bialaphos는 고등식물에 있어서 glutamine 합성을 억제하여 식물체를 고사 시키는 능력을 갖고 있다. 본 연구에서 acetylteansferase에 의해 encoding된 bialaphos 저항성 유전자(bar gene)는 세균(Pseudomonas sryngae pv tabaci)의 genomic DNA로부터 cloning된 것을 사용하였다. 수분시킨 담배의 화계에 일정한 시간별로 bar 유전자를 처리한 결과 수분 후 30-40시간 사이의 처리구 에서 형질전환 식물체가 가장 많이 얻어 졌다. 그러한 형질전환 식물체의 kanamycin과 bialaphos 저항성 형질은 자식후대(T$_1$, T$_2$)에 있어서도 우성형질로 유전되었으나 wild type의 담배는 상기의 약제를 처리 하였을때 전부 고사하였다. 그리고, T$_1$세대의 형질전환 식물체로부터 전 염색체 DNA를 추출하여 Southern 분석한 결과 bar 유전자가 식물의 염색체상에 안정하게 존재하는 것을 확인하였다. 이상의 결과로부터 담배의 수분, 수정 시기에 외부유전자인 bar를 화주에 처리함으로써 bialaphos 저항성 식물을 만들어낼 수 있었다. The herbicide bialaphos is a potent inhibitor of glutamine synthetase in higher plants. A bialaphos resistance (bar) gene encoding for an acetyltransferase was isolated from genomic DNA of Pseudomonas syringae pv tabaci. The bar gene was ligated to the binary vector pBI121. Pistils of tobacco plane were heated with the bar gene containing plasmid DNA at various times after pollination. When the treatment was applied at 30 and 40 h after pollination, a number of transgenic plants were obtained. Premary transformation (T$_{0}$ generation) and their progenies (T$_1$T$_2$) were resistant to both bialaphos and kanamycin at a dosage lathal to untransformed control plants. Stable integration of bar gene into chromosomal DNA was proven by Southern blot analysis of genomic DNA isolated from T$_1$progenies. These results show that the bialaphos resistant plane could be obtained by treatment to pistils with the exgenous bar gene through the fertilization cycle of tobacco.o.