Paenibacillus donghaensis JH8에서 세포외 Xylanase의 특성

임채성,오용식,노동현,Lim, Chae-Sung,Oh, Yong-Sik,Roh, Dong-Hyun 한국미생물학회 2011 미생물학회지 Vol.47 No.1

Xylanase is a class of enzymes that hydrolyze the linear polysaccharide ${\beta}$-1,4-xylan into xylose. This enzyme is applied in the process of paper making and may be used for the process of biofuel production in the future. The Paenibacillus donghaensis JH8, isolated from Donghae deepsea sediment and reported as a novel bacterium, was known to degrade xylan and its xylanase was characterized in this study. The enzyme was maximally induced in the presence of 0.1% xylan. The production of xylanase was started at early logarithmic phase and reached about 55 miliunit at stationary phase of growth. The optimal temperature and pH of extracellular xylanase were found to be $40^{\circ}C$ and pH 6.0, respectively. The activity of xylanase was inhibited by the presence of $Ca^{2+}$, $Mn^{2+}$, $Fe^{2+}$, $Cu^{2+}$, $Al^{3+}$ or EDTA, and activated by $K^+$, $Ag^+$ or DTT. This xylanase was stable at $40^{\circ}C$ for 120 min, but lost almost their activity in 30 min at $60^{\circ}C$. Zymography analysis of concentrated culture supernatant revealed one major band at 42 kDa and two faint bands at 68 and 120 kDa. Xylanase는 선형복합다당인 ${\beta}$-1,4-xylan을 xylose로 가수분해하는 효소의 한 종류이며, 종이제조공정에 응용되고 미래에 바이오 연료의 생산에 사용 될 수 있다. 동해 심층 퇴적물로부터 신종세균으로 보고된 Paenibacillus donghaensis JH8은 배지중의 xylan을 분해한다고 알려져 있으며, 여기에서는 이 효소의 특성을 조사하였다. 효소는 0.1% xylan 존재에서 최고로 유도되었으며, xylanase의 생산은 초기 대수성장기에 효소를 생산하기 시작하여, 정지기에서 약 55 miliunit에 도달하였다. 세포외성 xylanase의 최적온도와 pH는 각각 $40^{\circ}C$와 pH 6.0이였다. Xylanase의 활성은 $Ca^{2+}$ 및 $Mn^{2+}$, $Fe^{2+}$, $Cu^{2+}$, $Al^{3+}$, EDTA의 존재에 의해 억제되었고, $K^+$, $Ag^+$, DTT에 의해 활성화되었다. 이 xylanase는 $40^{\circ}C$에서 120분간 활성을 유지하며 안정하였지만, $60^{\circ}C$에서는 30분에서 거의 모든 활성을 잃어버리는 특성을 보여주었다. 농축된 배양 상등액의 zymography 분석시 42 kDa의 주 밴드와 68과 120 kDa에 두 개의 아주 희미한 밴드를 나타내었다.

직접 변환 방식을 이용한 주파수 혼합기

임채성,김성우,최혁환,이명교,권태하,Lim Chae-sung,Kim Sung-woo,Choi Hyek-Hwan,Lee Myoung-kyo,Kwon Tae-ha 한국정보통신학회 2005 한국정보통신학회논문지 Vol.9 No.6

In this paper, Mixer using the direct-conversion method intended to use in front-end of a RF receiver is designed. The direct conversion Mixer is an alternative wireless receiver architecture to the well-established superheterodyne, particularly for high integration, low power, and low cost. It operates at 2.4GHz band, and is designed and simulated with a 0.35um CMOS technology and HSPICE simulator. Layout is implemented with a Mentor IC Station. The 2.4GHz CMOS Mixer employs a modified single-balanced Gilbert Cell with additional MOSFET in the output stages to improve IIP2, which is a standard of linearity in direct conversion receiver. Additional coversion-stages's transconductances are controlled by each MOSFET's physical properties. The HSPICE simulation results show that the 2.4GHz CMOS Mixer has voltage gam of 29dB, IIP2 of 63dBm, respectively. The Mixer also draws 3.5mA from a 3.3V supply. 본 연구에서는 RF 수신단에 적용할 수 있는 직접 변환 방식의 주파수 혼합기를 설계하였다. 직접 변환 방식의 주파수 혼합기는 기존의 헤테로다인 방식에 비해 고집적화가 가능하고 저전력 및 저가의 설계가 가능한 구조이다. 제안된 주파수 혼합기는 $0.35{\mu}m$ CMOS 공정을 이용한 2.4GHz대에서 동작하는 RF CMOS 주파수 혼합기로써, HSPICE를 이용하여 시뮬레이션 하였고, 레이아웃은 멘토사의 IC Station을 이용하여 수행하였다. 기본 single-balanced Gilbert Cell의 출력단에 추가 변환을 수행하였고, 각 변환단의 전달 컨덕턴스 값을 조절하여 결과적으로 출력단에 나타나는 2차 혼변조 성분이 differential 출력에 의해 충분히 개선되도록 하였다. 3.3V의 공급전압으로 29dB의 높은 전압이득을 얻었고 3.5mA의 전류소모가 발생하였다. 2차 혼변조 성분을 줄이기 위한 구조적인 변화를 통해 63dBm의 IIP2 값을 얻었다.

말채나무 추출물의 ${\alpha}-amylase$ 저해 활성

임채성,이춘영,김용무,이위영,이해익,Lim, Chae-Sung,Li, Chun-Ying,Kim, Yong-Mu,Lee, Wi-Young,Rhee, Hae-Ik 한국응용생명화학회 2005 Applied Biological Chemistry (Appl Biol Chem) Vol.48 No.1

${\alpha}-Amylase$ 저해제는 소장에서 전분의 소화를 저해하여 포도당의 흡수를 지연시킴으로써 혈당 조절 목적으로 이용된다. 따라서 본 연구에서는 ${\alpha}-amylase$ 저해제를 탐색할 목적으로 국내 자생 목본류 약 1400여종의 70% ethanol 추출액을 대상으로 ${\alpha}-amylase$ 저해제 분포를 검색하였다. 수종의 목본류에서 ${\alpha}-amylase$ 저해제가 분포하고 있음이 확인되었으며, 그 중 활성이 비교적 높은 말채나무 기원의 저해제를 대상으로 연구를 진행하였다. 기원별 효소에 따른 저해 활성도를 살펴보면 salivary와 pancreatic ${\alpha}-amylase$, 미생물 기원의 ${\alpha}-glucosidase$에는 탁월한 저해 활성을 보인 반면 돼지 기원의 ${\alpha}-glucosidase$ 저해제에 대해서는 매우 낮은 저해 활성을 보였다. ${\alpha}-Amylase$와 ${\alpha}-glucosidase$의 kinetic을 분석하면 salivary와 pancreatic 두 효소에 모두 경쟁적 저해제로, 효모의 ${\alpha}-glucosidase$에는 비경쟁적과 반경쟁적의 혼합형 저해제로 나타났다. 또한 열과 산성에 대한 안정성을 확인한 결과 비교적 안정적인 것으로 나타났다. 본 추출물의 식이 섭취에 따른 혈당 강하 효과와 체중에 미치는 영향에서는 혈당과 체중 상승을 억제하는 효과가 확인되었고, mRNA수준에서 대퇴근 세포에 있어서 GLUT4의 발현이 증가됨을 확인하였다. ${\alpha}-Amylase$ inhibitor is used to control blood glucose level by inhibiting starch digestion in the small intestine and delaying the absorption of glucose. In this study, we investigated the effect of the ethanol extracts from more than 1400 species of plants against ${\alpha}-amylase$ with the aim of developing a new ${\alpha}-amylase$ inhibitor. In the results, Cornus walteri extracts showed the highest inhibition activity. The inhibitory effect of Cornus walteri extract on the carbohydrate hydrolysis enzymes has different sensitivities against ${\alpha}-amylase$ from salivary and pancreatin and against ${\alpha}-glucosidase$ from yeast and porcine small intestine. In the study of inhibition kinetics of ${\alpha}-amylase$ and ${\alpha}-glucosidase$, Cornus walteri extract showed competitive inhibition against salivary and pancreatin while showing the combination of uncompetitive and noncompetitive inhibition against ${\alpha}-glucosidase$. The Cornus walteri extract was stable at acidic and thermal conditions. As for the blood glucose and body weight levels of Cornus walteri extract, we confirmed anti-hyperglycemic and anti-obesity effects. Also, in the investigation of the mRNA lever, Cornus walteri extract upregulated the level of GLUT4 mRNA in the quadriceps muscle.

과학학습의 정의적 영역에서 사전-사후 통합 검사 설계의 타당화 연구: 과학영재를 대상으로

임채성,박형민,Lim, Chae-Seong,Park, Hyoung-Min 한국초등과학교육학회 2017 초등과학교육 Vol.36 No.3

In this study, the reliability and validity of the retrospective pre-post test were analyzed in order to solve the problem of traditional pre-post test including response shift bias. Samples of the study were 162 elementary school students who are studying at the S university gifted education center in Seoul. Before completion of the field trip, we conducted pre test of science-related attitudes. After completion of the field trip, respondents were asked to compare their responses of pre and post science-related attitudes to quantitatively analyze the commonalities and differences of the two tests. To find out more characteristics, qualitative data such as daily records and interview were also gathered and analyzed. The major results of the study are as follows. First, for the paired t-test, there was no statistically significant difference between separate pre-test scores and retrospective pre-test. There was a very high correlation between the separate pre-test scores and the retrospective pre-test. Second, there were significant differences in all seven sub-factors of science-related attitudes between the retrospective pre-test and the post-test. Third, the separate pre-test scores showed a slightly higher tendency than the retrospective pre-test scores. This suggests that the response shift bias appears when it is performed the separate pre-test in affective domain. As a result of the interview, it was found that the evaluation standards of separate pre-test did not match with those of post-test. Forth, internal consistency reliability of the retrospective pre-test was higher than that of the separate pre-test. However, there were significant differences in six factors of science-related attitudes excluding the 'social implications of science' between the separate pre-test and the post-test. Based on these results, the retrospective pre-post test design provides simplicity and convenience to both respondents and investigators, as it is done with one test. The retrospective pre-post test design can be regarded as a valid design for the self-report measurement of affective domain on a single experimental group.

연구논문 : 뇌 기반 진화적 과학 교수학습 모형을 적용한 초등학교 학생의 자유 탐구 활동에서 과학 태도와 흥미 주제 영역 분석

임채성 ( Chae Seong Lim ),김재영 ( Jae Young Kim ),백자연 ( Ja Yeon Baek ) 한국초등과학교육학회 2012 초등과학교육 Vol.31 No.4

Interest is acknowledged to be a critical motivational variable that influences learning and achievement. The purpose of this study was to investigate the interest of the elementary students when free inquiry activities were performed through a brain-based evolutionary scientific teaching and learning model. For this study, 106 fifth grade students were chosen and performed individually free inquiry activities. The results of this study were as follows: First, after free inquiry activities, as to free inquiry science related attitude, a statistically significant difference was not observed. But they came to have positive feelings about the free inquiry. Especially students marked higher mean score in openness showed consistency in sub-areas of free inquiry science related attitude. Second, students had interests in various fields, especially they had many interests in area of biology. They chose inquiry subjects that seems to be easily accessible from surrounding and as an important criterion of free inquiry they thought the possibility that they could successfully perform it. And students who belong to the high level in the science related attitudes and academic achievement diversified more topics. Third, most of students failed to further their topics. However, the students who specifically and clearly extended their topics suggested appropriate variables in their topics. On the other hand, students who couldn`t elaborate their topics were also failed to suggest further topics and their performance of inquiry was more incomplete. In conclusion, the experiences of success in free inquiry make the science attitude of students more positive and help them extend their inquiry. These results have fundamental implications for the authentic science inquiry in the elementary schools and for the further research.

특집 : 경제사학회 50주년 기념; 회고와 전망 : 동아시아 전시,전후 경제사 -일본제국권 전시동원의 경험과 전후 재편-

임채성 ( Chai Sung Lim ) 경제사학회 2013 經濟史學 Vol.55 No.-

본고는 중일전쟁 이후 일본제국권외 전시동원과 이에 대항하여 전개된 중국측의 전시경제체제 그리고 전후 재편기에서 나타난 다양한 역사적 경로가 연구사적으로 어떻게 고찰되어 왔는지를 검토하였다. 이를 통해 중일전쟁 발발 이후 국가통제에 의한 계획화가 이루어졌고 전후에는 시장경제로의 전환이 이루어지며 전전과는 다른 경제구조가 정착했음을 알 수 있었다. 그러나 각 지역에서의 양상은 극히 달랐다. 전후 일본과 달리 한반도와 중국 대륙에서는 또 한 차례의 전시 동원을 경험하였고 이것이 이들 지역 연구에 관한 인식을 복잡하게 만드는 요인이 되었다. 아이러니하게도 북한과 중국은 전후 민족주의적 성격을 강하게 드러냈음에도 불구하고 전시경험과의 연속성이 강하다고 인식되고 있다. 동아시아에 관한 관심이 증대되고 있는 현 시점에서 볼 때 향후 지역사적 관점에서 다양한 형식의 멀티내셔널 실증 연구가 진척될 것으로 전망된다. This article examines how the wartime mobilization of the Japanese Empire, the oppositional wartime economic system of China, and the postwar reorganization of East Asia have been investigated and discussed in various historical path analysis studies. Since the outbreak of the first Sino-Japanese War, the economic planning was reinforced through the governmental control. The transition from a planned economy to a market economy was carried out during the postwar period and its economic structure became quite different from the prewar one. However, each local economy had its own characteristics from that aspect. Compared to Japan, Korea and China after the second world war experienced the wartime mobilization once again and these situations complicated the economic and historical recognition of East Asia. Ironically, we are able to find that North Korea and China strongly inherit the historical continuity from the wal1ime experience in spite of their nationalistic arguments. As the regional economic prosperity of the East Asia recently draws much academic attention, different types of multinational empirical researches are expected to advance in terms of the regional history.

뇌기반 진화적 과학 교수학습 모형의 개발

임채성 ( Chae Seong Lim ) 한국과학교육학회 2009 한국과학교육학회지 Vol.29 No.8

한국 중소 기업 기술능력 평가 틀의 모색 - 21개 기업 사례 연구

임채성(Chai-Sung Lim),이근(Keun Lee),권영섭(Young-Sub Kwon),권용수(Yong-Soo Kwon),서중해(Jung-Hae Suh) 한국생산관리학회 2004 韓國生産管理學會誌 Vol.15 No.2

본 연구는 기술능력 감사도구를 활용하여 중소기업의 기술혁신 과정과 관련된 기술능력을 평가해 본 국내 최초의 연구이다. 21개 기업에 대해 감사를 실시한 결과 중소기업들은 기술향상을 위한 변화의 필요성의 인식, 탐색 및 기술획득에 있어 비교적 적극적이나, 기술 전략수립 등을 통한 변화의 효율적인 과정을 관리하는 데 있어서는 취약한 면을 보여 주었다. 또한 중소기업의 기술능력은 산업별로 차이가 있었고 중소기업들 간의 기술능력 격차가 켰다. 이 가운데 일부 기업은 최상의 기술능력 수준인 '창조적'인 기업으올 평가되는 기업이 발견되었다. 본 연구에서 쓰인 감사 도구는, 베상트 등(2002)이 개발한 것으로, 방문 인터뷰 및 설무조사로 중소기업의 기술능력에 대한 종합적인 평가를 해 볼 수 있는 도구로 평가되었으나 아울러 문제점도 발견되었다. 국내 기업 기술능력의 종합적인 파악과 정확한 평가를 위해 감사도구에 대한 보다 많은 연구가 필요하다. This study is the first study, in Korea, which evaluates technological capability of Korean small firms with a technlogical capability audit tool. Among the items of technological capability assessed, small firms were stronger in search and technology acquisition and the recognition of the need for change than in other items, while weaker in technology strategy and managing the further process of implementing technical changes. Also there was a wide gap of technological capability among small firms, some of which were found to have reached to the technological capability of 'creative' firms which are the firms with highest technological capability according to the taxonomy of tirms in the audit tool. The audit tool, devoloped by Bessant at al(2002), was found to bo useful for quick assessment of technological capability in a short time visit, however it revealed problems. The tool needs to be developed further by incorporating the specificity of Korean Small firms in assessing the Korean firms'technological capability.

연구논문 : 과학창의성 평가 공식의 개발과 적용

임채성 ( Chae Seong Lim ) 한국초등과학교육학회 2014 초등과학교육 Vol.33 No.2

Researchers have employed a diversity of definitions and measurement methods for creativity. As a result, creativity research is underrepresented in the literature and the findings of different studies often prove difficult to draw into a coherent body of understanding. With regard to assessment, there are some important problems both in creativity research and practice, such as originality bias and Big-C creativity bias in teachers` perceptions about creativity and creative thinking, and additive rather than multiplicative scoring systems of creativity assessment. Drawing upon most widely accepted conceptions of the creativity construct, I defined ‘student`s scientific creativity’ as the ability to make a product both original and useful to the student in terms of little c creativity, and ‘scientist`s scientific creativity’ as the ability to come up with a product both original and useful to the science community in terms of Big-C creativity. In this study, an ‘Assessment Formula for Scientific Creativity’ was developed, which is consisted of the multiplication of originality and usefulness scores rather than the sum of the two scores, and then, with scores calculated from the assessment formula, the scientific explanations generated by children were categorized into four types: routine, useful, original, and creative types. The assessment formula was revealed to be both valid and reliable. The implications of the assessment formula for scientific creativity are examined. The new assessment formula may contribute to the comprehensive understanding of scientific creativity to guide future research and the appropriate interpretation of previous studies.

일본 동경권 대형사철의 경쟁구조와 경영비교분석

임채성(Chai-Sung Lim) 한국철도학회 2007 한국철도학회논문집 Vol.10 No.1