• 미생물학회지
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• 제23권4호
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• pp.302-308
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• 1985

L-Ascorbic aciddm ltodcp 산화분해과정중 ${\alpha}$-ketoaldehyde의 한 종류인 3,4,5-trihydroxy-2-keto-L-valeral-dehyde(L-xylosone)가 형성된다는 사실을 핵자기공명스펙트럼분석법으로 확인하였다. 이 물질은 glyoxalase system에 의해 L-xylonic acid로 변환되고 계속해서 L-erythroascorbic acid로 산화된다. 이러한 근거 위에서 vitamin C의 분해과정이 vitamic C 이외의 두종류의 ${\gamma}$-lactones-과 3종류의 ${\alpha}$-ketoaldehydes로 구성된 분해경로를 갖는다는 사실을 제안하였다.

• 영어어문교육
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• 제16권4호
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• pp.201-222
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• 2010

The purpose of this study is to investigate /l/-deletion in lC clusters which are composed of a lateral followed by consonants at syllable-final position in English. For this, I have analyzed /l/-deletion in words depending on conditions and theoretical analyses such as Sonority Sequencing Generalization, Cluster Simplification, Complex sounds and merger, and Feature Geometry, but they didn't offer a very satisfactory explanation to the phenomenon. Therefore, I adopted a historical approach in order to determine the cause and origin of /l/-deletion in lC clusters, and then as a phonological analysis tool, I relied on the constraints and their ranking in Optimal Theory framework for explaining /l/-deletion in the clusters more consistently. As a result, I can explain the phenomenon more explicitly than from the above mentioned analyses.

• Journal of Microbiology and Biotechnology
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• 제17권5호
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• pp.721-727
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• 2007

Stability-enhanced mutants, H44, 11-94, 5A2-84, and F8, of L-threonine aldolase(L-TA) from Streptomyces coelicolor A3(2)(SCO1085) were isolated by an error-prone PCR followed by a high-throughput screening. Each of these mutant, had a single amino acid substitution: H177Y in the H44 mutant, A169T in the 11-94 mutant, D104N in the 5A2-84 mutant and F18I in the F8 mutant. The residual L-TA activity of the wild-type L-TA after a heat treatment for 20 min at $60^{\circ}C$ was only 10.6%. However, those in the stability-enhanced mutants were 85.7% for the H44 mutant, 58.6% for the F8 mutant, 62.1% for the 5A2-84 mutant, and 67.6% for the 11-94 mutant. Although the half-life of the wild-type L-TA at $63^{\circ}C$ was 1.3 min, those of the mutant L-TAs were longer: 14.6 min for the H44 mutant, 3.7 min for the 11-94 mutant, 5.8 min for the 5A2-84 mutant, and 5.0 min for the F8 mutant. The specific activity did not change in most of the mutants, but it was decreased by 45% in the case of mutant F8. When the aldol condensation of glycine and 3,4-dihydroxybenzaldehyde was studied by using whole cells of Escherichia coli containing the wild-type L-TA gene, L-threo-3,4-dihydroxyphenylserine(L-threo-DOPS) was successfully synthesized with a yield of 2.0 mg/ml after 20 repeated batch reactions for 100 h. However, the L-threo-DOPS synthesizing activity of the enzyme decreased with increased cycles of the batch reactions. Compared with the wild-type L-TA, H44 L-TA kept its L-threo-DOPS synthesizing activity almost constant during the 20 repeated batch reactions for 100 h, yielding 4.0 mg/ml of L-threo-DOPS. This result showed that H44 L-TA is more effective than the wild-type L-TA for the mass production of L-threo-DOPS.

• Journal of Acupuncture Research
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• 제18권5호
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• pp.77-91
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• 2001

Backgrounds and purpose : The acupuncture of oriental medicine is very important in treatments. Until now it was been researched according to the meridian and qi xue(氣血) phenomenon of oriental medicine's theory. Acupuncture will show more objective index to observe the meridian. And then, I studied the effects on the thermal change of the Taeyon($L_9$) and Chungbu($L_1$) following acupuncture stimulation. Objective and Methods : This study was performed from December 1999 to February 2000 on 60 healthy students. The objective was divided into two groups, those are the control group A(N=30) that no acupuncture stimulation, the group B(N=30) of acupuncture stimulation on Taeyon($L_9$). First, in the control group A, I took a picture Taeyon($L_9$) Chungbu($L_1$) Taenung($P_7$) Chondol($CV_{22}$) area for 30 men without any stimulation with the Digital Infrared Thermograph Imaging(D.I.T.l.) and did same area, 10min after. Second, in the acupuncture stimulation group B, we took a picture Taeyon($L_9$) Chungbu($L_1$) Taenung($P_7$) Chondol($CV_{22}$) area for 30 men without any stimulation with the Digital Infrared Th - ermograph Imaging(D.I.T.I.), and then stimulate acupuncture on Taeyon($L_9$) and took a picture same area, 10min after. Results : 1. In healthy men, average skin temperture on Taeyon($L_9$) area was lower than Chungbu($L_1$) area about $3.0^{\circ}C$, in the Lt. Taeyon($L_9$) and Chungbu($L_1$) area was lower than Rt. Taeyon($L_9$) and Chungbu($L_1$) area. 2. In the acupuncture stimulation group B, the skin temperature of both side Taeyon($L_9$) area showed the increase or decrease significantly. But both Taenung($P_7$) area did not showed significantly. 3. In the acupuncture stimulation group B, the skin temperature of both side Chungbu($L_1$) area showed the increase or decrease significantly. But both Chondol($CV_{22}$) area did not showed significantly. 4. The thermal changes of the area which is a meridian point in the Lung Meridian of the acupuncture stimulation group on Taeyon($L_9$) different from other Meridian with significantly change. Conclusion : The acupuncture stimulation on Taeyon($L_9$) affected the thermal change of the area which is a meridian point, in the Lung Meridian. And then I could relate these results with the existence of the meridian and meridian point. Thus, continuous thermographic study will be needed for the existence of the meridian and meridian point.

• 한국미생물·생명공학회지
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• 제18권1호
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• pp.49-55
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• 1990

D,L-2-aminothiazoline-4-carboxylic acid(D,L-ATC)로 부터 L-cysteine으로의 bioconversion에 대한 특성을 살펴보았다. Pseudomonas species의 배양중에 D,L-ATC를 첨가하여 균체내에 그 관여되는 효소를 유도, 생성시키고 균체만을 모은 후 파쇄하여 조효소액을 제조하였다. 실험결과, DL-ATC로 부터 L-형의 cysteine 만이 생성되며, 이 반응에 관여되는 효소는 cofactor로서 Mn이온을 필요로 하며, Mn 이온의 첨가에 의해 L-cysteine의 생성량이 수십배 증가되었다. 그러나, 이 효소는 생성물인 L-cysteine에 의해 feedback inhibition을 받았다. 한편, L-cysteine의 분해효소가 조효소액 내에 존재하며 그 효소반응의 저해제없이는 생성된 L-cysteine의 대부분이 분해되었다. 반면, 매우 효과적인 효소저해제인 hydroxylamine의 첨가로 L-cysteine의 분해를 거의 방지할 수 있었다.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제15권4호
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• pp.353-364
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• 2008

The purpose of this paper is to investigate the finite extension of weighted word L-delta groups. The paper revealed that a finite extension of a weighted word L-delta group is a weighted word L-delta group, and an abelian group, in addition, is a weighted word L-delta group and simultaneously a word L-delta group.

• BMB Reports
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• 제36권5호
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• pp.488-492
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• 2003

Neurofilament-L (NF-L) is a major element of neuronal cytoskeletons and known to be important for neuronal survival in vivo. Since oxidative stress might play a critical role in the pathogenesis of neurodegenerative diseases, we investigated the role of copper and peroxide in the modification of NF-L. When disassembled NF-L was incubated with copper ion and hydrogen peroxide, then the aggregation of protein was proportional to copper and hydrogen peroxide concentrations. Dityrosine crosslink formation was obtained in copper-mediated NF-L aggregates. The copper-mediated modification of NF-L was significantly inhibited by thiol antioxidants, N-acetylcysteine, glutathione, and thiourea. A thioflavin-T binding assay was performed to determine whether the copper/$H_2O_2$ system-induced in vitro aggregation of NF-L displays amyloid-like characteristics. The aggregate of NF-L displayed thioflavin T reactivity, which was reminiscent of amyloid. This study suggests that copper-mediated NF-L modification might be closely related to oxidative reactions which may play a critical role in neurodegenerative diseases.

• 음성과학
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• 제8권2호
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• pp.93-106
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• 2001

The pronunciation of English l and r was a consistent problem in learning English in Korea as well as Japan. This problem occurs from the fact that in Korea and Japan there is only one liquid sound. Substituting the Korean liquid for English l and r was a common error. The pronunciation of the dark l causes a further problem in pronouncing the English l sound. To see the relationship between the English l, r, and the Korean liquid sound, an electropalatographic (EPG) experiment was done. The findings were (1) there were no tongue contacts either on the alveolar ridge or on the palate during the articulation of the dark l. (2) The Korean liquid sound was different in the tongue contact points either from English l or r. The English clear l consistently touched the alveolar ridge in the forty tokens, but the Korean liquid sound in the intervocalic and word-final position touched mainly the alveopalatal area. The English r touched exclusively the velum area. The Korean intervocalic /l/ was similar to English flap in EPG and spectrographic data. There was evidence that the word-final Korean /l/ is a lateral.

• 생명과학회지
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• 제19권8호
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• pp.1033-1038
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• 2009

포도당 및 간장박의 농도가 각각 20 g/l 및 10 g/인 배지에서 Sphingomnas paucibilis NK2000가 생산하는 젤란의 최대 생산성은 배지의 초기 pH를 6.8로 하였을 경우, 플라스크 규모에서 7.46 g/l이었으며, 7 l 생물배양기에서는 7.35 g/l이었다. 배지의 pH를 6.8로 유지하면서 7 l 생물배양기에서 젤란을 생산할 때, 젤란의 최대 생산성은 pH 조절제로 수산화나트륨을 사용하였을 경우에 8.42 g/l 이었으며, 인산칼슘을 사용하였을 경우에 8.50 g/l이었다. Sphingomnas paucibilis NK2000를 배양하여 젤란을 생산할 경우에 배지에 첨가되는 인산칼슘의 최적 농도는 5.0 g/l이었다. 인산칼슘의 농도가 5.0 g/l인 배지를 사용하여 7 l 생물배양기에서 젤란을 생산하였을 때, 젤란의 최대 생산성은 8.93g/l이었다. 본 연구를 통하여 배지의 pH를 조절하지 않고 인산칼슘의 농도를 최적화한 배지를 사용하여 젤란의 생산성을 향상시킬 수 있는 경제적인 방법을 개발하였다.

• Korean Journal of Mathematics
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• 제15권2호
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• pp.121-133
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• 2007

We introduce the notions of (L,M)-neighborhood spaces and (2,M)-fuzzifying neighborhood spaces. We investigate the relations among (L,M)-neighborhood spaces, (L,M)-topological spaces and (2,M)-fuzzifying neighborhood spaces.