• Title/Summary/Keyword: STN

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A study of Succinyl trialanine p-nitroanilide hydrolytic activity in workers exposed to organic solvents (유기용제 취급 근로자들의 Succinyl trialanine p-nitroanilide 가수분해 효소 활성에 관한 연구)

  • Oh, Hae-Ju;Roh, Jae-Hoon
    • Journal of Preventive Medicine and Public Health
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    • v.26 no.1 s.41
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    • pp.74-85
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    • 1993

  • To measure the serum succinyl trialanine p-nitroanilide hydrolytic activity as new index of liver function in workers exposed to organic solvents, this study conducted 114 workers in department of shoe-making of shoes factories. The results obtained from this study were as follows : 1. The mean values of serum GOT, GPT, ${\gamma}GT$ in whole workers were $22{\pm}12.32,\;20{\pm}9.05,\;28{\pm}21.35IU/l$, respectively and the mean value of serum STN hydrolytic activity was $0.08{\pm}0.05$. 2. The serum STN hydrolytic activity was significantly higher for male (p<0.05) and there was no difference among the groups of age. 3. There was no difference in the groups by working hours but significant difference in persons who worked over 3 years or were exposed to toluene over 100ppm (p<0.05). 4. The correlation of the exposed dose of toluene and serum GOT, GPT, ${\gamma}GT$ and serum STN hydrolytic activity were statistically significant (r=0.027-0.518). 5. The exposed dose of toluene was most explainable variable and statistically significant among the factors affecting serum STN hydrolytic activity (p<0.05).

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Molecular Analysis of Salmonella Enterotoxin Gene Expression

  • Lim, Sang-Yong;Seo, Ho-Seong;Yoon, Hyun-Jin;Choi, Sang-Ho;Heu, Sung-Gi;Ryu, Sang-Ryeol
    • Journal of Microbiology and Biotechnology
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    • v.13 no.4
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    • pp.598-606
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    • 2003

  • Salmonella encodes an enterotoxin (Stn) which possesses biological activity similar to the cholera toxin. Stn contributes significantly to the overall virulence of S. typhimurium in a murine model. The production of Stn is enhanced in a high-osmolarity medium and by contact with epithelial cells. In the present study, the in vitro and in vivo transcriptional regulations of the sin promoter revealed two promoters, P1 and P2. The P1 promoter identified by a primer extension analysis of stn mRNA exhibited a switching mechanism in vivo. Depending on the growth stage, transcription was initiated from different start sites termed $P1_S\;and\;P1_E$. $P1_S$, recognized by RNA polymerase containing ${\sigma}^S(E{\sigma}^S),\;and\;P1_E$, recognized by $E{\sigma}^70$, were activated during the stationary and exponential phases, respectively, while $P1_S\;and\;P1_E$ were both negatively regulated by CRPㆍcAMP and H-NS. Results revealed that $P1_S$ was the responsible promoter activated under a high osmolarity and low pH. The P2 promoter was identified 45 nucleotides downstream from $P1_E$ and negatively controlled by CRPㆍcAMP in vitro. No P2 activity was detected in vivo. The regulation of stn expression monitored using a Pstn::egfp fusion indicated that $E{\sigma}^S$ was required for the induction of stn and various factors were involved in stn regulation inside animal cells.

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A Video-Rate Super-Twisted Nematic (STN) Liquid Crystal DisplayUusing a New Row Signal Modulation Method (새로운 행 신호 변조 방법에 의한 고속 STN 액정표시기)

  • 이승우;한철희
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.35D no.5
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    • pp.69-79
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    • 1998

  • In this paper, we have proposed a new row signal modulation method in order to display multi-gray image using super-twisted nematic liquid crystal display (STN-LCD), which has no complex computation, high selection ratio, and low driving voltage. By the proposed method, we have implemented a 320*240, 8-gray video-rate STN-LCD. For achieving a video-rate STN-LCD, 6 lines are selected at a time. Each row line is selected 8 times by equally distributed pulses throughout one frame. As a result, we can get 8 gray, video-rate image. The repetive horizontal pattern and the filckering was analyzed and the improvements have been presented.

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