• The Zoological Society Korea : Newsletter
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• v.12 no.2
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• pp.98.1-98
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• 1995

No Abstract, See Full Text

• Proceedings of the Zoological Society Korea Conference
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• 1995.10b
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• pp.226.1-226
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• 1995

No Abstract, See Full Text

• Biomedical Science Letters
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• v.11 no.2
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• pp.165-173
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• 2005

A potent demethylating agent, 5-Azacytidine (5-AzaC) has been widely used as in many studies on DNA methylation, regulation of gene expression, and cancer biology. The mechanisms of the demethylating activity were known to be formation of complex between DNA and DNA methyltransferase (MTase), which depletes cellular MTase activity. However, 5-AzaC can also induce hypermethylation of a transgene in a transgenic cell line, G12 cells and it was explained as a result of defense mechanisms to inactivate foreign gene(s) somehow. This finding evoked the question that whether the phenomenon of hypermethylation induced by 5-AzaC is limited to the transgene or it can be occurred in endogenous gene(s). In order to answer the question, mutagenicity test of 5-AzaC and molecular characterization of mutants obtained from the test were performed using an endogenous gene, thymidine kinase (tk) in Chinese hamster V79 cells. When V79 and V79-J3 subclone cells were treated with 1, 2.5 ,5, $10{\mu}M$ of 5-AzaC for 48 hours, their maximum mutant frequencies were revealed as $6\times10^{-3}\;at\;5{\mu}M$(350-fold induction over background) and $8\times10^{-3}\;at\;2.5{\mu}M$ (l,800-fold induction over background) respectively. Since the induction rates were too high to be induced by true mutations, many trifluorothymidine (TFT)-resistant $(TFT^R)$ cells were subjected to Northern blot analysis to check the presence of tk transcripts. Surprisingly, all clones tested possessed the transcripts in a similar level, that implicates the $TFT^R$ phenotype induced by 5-AzaC has not given rise to hypermethylation of the gene in spite of unusually high mutation frequency. In addition, it has shown that the TK activity in the pool of 5-AzaC-induced $TFT^R$ cells has about a half of that in spontaneously-induced $TFT^R$ cells or in non-selected parental V79-J3 cells. This result suggests that the mechanism(s) underlying the TFT-resistance between spontaneously occurred and 5-AzaC-induced cells may be different. These findings have shown that the $TFT^R$ phenotype induced by 5-AzaC has not given rise to hypermethylation of the tk gene, and 5-AzaC may be induced by one or combined pathways among many drug resistance mechanisms. The exact mechanisms for the 5-AzaC-induced $TFT^R$ phenotype remain to elucidate.

• Preventive Nutrition and Food Science
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• v.6 no.3
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• pp.187-191
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• 2001

Effects of kochujang (Korean red pepper soybean paste) extracts on tumor formation, natural killer (NK) cell activity in spleen and glutathione S-transferase (GST) activity in liver were investigated in the sarcoma-180 cell transplanted mice. Inhibitory effects of these samples on lung metastasis of colon 26-M3.1 cells were also evaluated in the Balb/c mice. The injection of methanol extracts from traditional kochujang I (TK I, 0-day fermented), II (TKII, 6-month fermented), commercial kochujang (CK, 1-month fermented) and red pepper powder (RPP) significantly reduced tumor formation in Balb/c mice (p<0.05), TKII decreased tumor growth by 46% compared with control, resulting in the smallest tumor weight. The transplantation of sarcoma-180 cells increased the spleen/body weight ratio of Balb/c mice, while TKI and TKll significantly decreased this index (p<0.05). The effect of TKll and CK, fermented kochujang, on the NK cell activity of splenocytes was higher than that of sarcoma-180 cells transplanted control group. TK II recovered the activity of hepatic GST that was decreased by the transplantation of sarcoma- 180 cells in to the mice. All kochujang-treated mice had significantly fewer lung metastatic colonies than control mice. TKII was the most effective in inhibiting lung metastasis of colon 26-M3.1 cells. These results indicated that optimally ripened (6-month) TK had more suppressive effects on tumor formation and lung metastasis than RPP and kochujang without fermentation and commercially prepared kochujang in mice.

• Journal of the Korea Society of Computer and Information
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• v.8 no.4
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• pp.28-34
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• 2003

ASN.1 is the most fundamental technology in network management. The develoment of ASN.1 environment requires three steps : compiler work to parse ASN.1 languages, updating database with the parsing results, and pretty-printing work for data in the database. This paper presents the design and implementation of the translator which automatically translates the specification of ASN.1 to the object-oriented language C++. This system provides a total environment including for various graphic user interface, DB interface, browser to develop ASN.1 for development environment of ASN.1 For the implementation, Objectivity DB is used for database, flex and yacc for compiling, and Tcl/Tk for user interface.

• The KIPS Transactions:PartC
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• v.11C no.4
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• pp.463-470
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• 2004

ASN.1/GDMO is the management object used in network management of TMN(Telecommunication Management of Network). However, ASN.1/GDMO is not directly used for managing the network, but translated Into a language with object-oriented paradigm. Therefore we need a development environment for handling ASN.1/GDMO. In this paper we present an integrated development environment(IDE) which consists of an editor and a browser. A user manages ASN.1/GDMO elements with GUI. The IDE is implemented with FLEX and BYACC in UNIX. And Objectivity DB is used as the DB and Tcl/Tk is used for developing GUI. This paper shows how the integrated environment of ASN.1 and GDMO works, and that it enables to manage efficiently the network.

• The Mathematical Education
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• v.57 no.1
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• pp.1-36
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• 2018

The purpose of this study is to examine the relationship between utilization of technology and TPACK in mathematics teachers, and to analyze needs and retentions, difference between needs and retentions, and educational needs of TPACK in mathematics teachers. Furthermore, we will prioritize TPACK items that mathematics teachers want to change, and provide implications for teacher education related to TPACK in the future. To do this, we analyzed 328 mathematics teachers nationwide by using survey on the utilization of technology, averages of TPACK's needs and retentions, t-test of two averages, Borich's educational needs analysis, and the Locus for Focus model. The results are as follows. Firstly, the actual utilization rate was lower than the positive recognition of utilization of technology by mathematics teachers, and many mathematics teachers mentioned the lack of knowledge related to TPACK. Secondly, the characteristics of in-service mathematics teacher's needs and retentions for TPACK were clear, and TPACK's starting line of in-service mathematics teacher can be different from pre-mathematics teacher's. The retentions was high in the order of CK, PCK and PK, and the needs was higher in the order of TPACK, TCK, TK and TPK. All of the higher retentions were knowledge related to PCK, and the value of CK was extremely high among them. In addition, mathematics teachers recognized needs for integrated knowledge related to technology, and they needed more TCK than TPK. The difference between needs and retentions showed that all items except two items in the PK were significant. Retentions of all items in CK was higher than needs, needs of all items in TK, TCK, TPK and TPACK was higher than retentions, PK and PCK were mixed. Thirdly, based on the analysis of Borich's educational needs and the Locus for Focus model, teacher education on TPACK for mathematics teachers needs to focus on TPACK, TK, TCK, and TPK. Specifically, TPACK needs to combine technology in terms of creativity-convergence, mathematical connections, communication, improvement of evaluation quality, and TK needs to new technology acquisition, function of utilizing technology, troubleshoot problems with technology, TCK needs to mathematical value(esthetic, practical) with technology, and TPK needs to consider technology in terms of evaluation methods, teaching and learning methods, improvement of pedagogy. Therefore, when determining the direction of teacher education related to TPACK in the future, if they try to reflect these items in detail, the teachers could participate more actively and receive practical help.

• Journal of The Korean Astronomical Society
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• v.29 no.spc1
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• pp.381-383
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• 1996

A new CCD camera equipped with a large format chip is now under construction for the Kiso 105-cm Schmidt telescope. We use SITe TK2048E, of which pixel size is 24 ${\mu}m$ and chip size is 48 mm square. TK2048E is thinned back-illuminated so that it has high sensitivity in U-band. The chip is cooled by a refrigerator instead of liquid nitrogen. MESSIA III is used as CCD control system.

• Microbiology and Biotechnology Letters
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• v.18 no.6
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• pp.640-646
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• 1990

We have cloned the cdd gene from E. coli C600 using (cdd-) as a host. From the sequenced promoter region of E=, coli cdd gene which has been determined by Valentin-Hansen P. (1985), we synthesized the 23 mer oligonucleotides corresponding to the transcription initiation region and used as a probe for cloning of the cdd gene by Southern blotting. The isolated fragments in the blotting were introduced to the colony hybridization after transforming it into the E. coli JF611 (cdd-, pyr double mutant), and we identified the hybridized band at 27 kb long. From the original insert of 27 kb fragment in theBamHI site of pBR322, the 5.3 kb fragment containing the cdd gene was isolated by subsequent deletion and subeloning. From the derived plasmid pTK509, further deletion and subcloning were performed and clarified that the cdd gene was located in the 2.1 kb of SaZI/DraI segment in the insert of pTK605. The polypeptide encoded by the cloned DNA was appeared to be a molecular mass of 33,000.

• Journal of the Korean earth science society
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• v.39 no.6
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• pp.600-616
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• 2018

The purpose of this study was to explore how primary school students develop their interest in science. A survey questionnaire was used to investigate students' interest, change of their interest, and engagement in science related activities three times a year. 201 students of two primary schools in Seoul Metropolitan City initially participated in this study. A follow-up case study was conducted with students who showed an increased interest in science. Finally, seven students were chosen in the case study. They were asked to keep a photo journal for 12 weeks, and were interviewed in every other week by one of the researchers. Among these seven participants, two (TK and QQ) were chosen for analyzing their data in this case study because they showed positive changes in developing science interest throughout the study. The results of two participants' survey, photo-journal and interview were analyzed qualitatively. First, TK, whose science interest developed from situational interest II to individual interest I, engaged in doing experiments at home, doing mathematics activities, raising pets or plants, observing phenomena, and visiting informal educational centers. He tended to participate in hands-on activities by himself in out-of-school settings. Second, QQ who developed from situational interest I to situational interest II, engaged in taking pictures as a representative activity at home and school. He tended to participate in activities with either his father or one of the researchers. Both students showed personal characteristics such as doing place-based activities, interaction with others and activity subjectivity. The goal of TK's interactions with others on the various places was to develop in cognitive domain. On the contrary, QQ's goal of interactions with others was to develop in emotional communication. This study reported the cases of characteristics of students who developed their interests in science including activities in- and out-of-school settings and their accompanying people.