• Journal of the Korean Chemical Society
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• v.43 no.5
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• pp.540-546
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• 1999

Solution conformation of cyclo-($Gln^1-Trp^2-Phe^3-{\beta}Ala^4-Leu^5-Met^6$), new NK-2 antagonist in dimethyl sulfoxide solution, has been determined by the use of two-dimensional nuclear magnetic resonance spectroscopy combined with simulated annealing calculations. The peptide exhibited converged structures with the atomic root-mean-square difference for the backbone atoms ($N,\;C^{\alpha},\;C'$) of all residues being 0.02${\AA}$ in the 25 annealed structures. The analysis of the structures indicated that the cyclic peptide has three intramolecular hydrogen bonds between $Met^6NH$ and ${\beta}Ala^4CO$, ${\beta}Ala^4NH$ and $Met^6CO$, $Phe^3NH$ and $Met^6CO$, and contain a type-I ${\beta}$-turn with Gln and Trp and ${\gamma}$-turn with Leu. The addition of an extra methylene group to Gly, i.e. P-Ala residue, may relax some unfavorable restraints in the cyclic backbone structure, hence enabling an additional hydrogen bond, which results in stabilizing one conformation.

• Proceedings of the PSK Conference
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• 2003.10a
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• pp.91-91
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• 2003

The beta-turn has been implicated as an important conformation for biological recognition of peptides or proteins. We adapted the concept of general Ca atom positioning from the cluster analysis and recombination of each ideal beta-turn conformation pattern by Garland and Dean (1. Computer-Aided Molecular Design, 1999, 13, 469) as one strategy of designing non-peptide beta-turn scaffolds. (omitted)

• Bulletin of the Korean Chemical Society
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• v.23 no.10
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• pp.1369-1390
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• 2002

• 한국해양학회지
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• v.10 no.1
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• pp.17-24
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• 1975

In order to clarify the accumulation of radioactive materials in marine organisms of Korea, the present investigation is carried out with 54 samples of edible seaweeds collected from eight sampling sites along the coast of Korea during September, 1973 and April, 1974. In this paper, ash contents, gross alpha activities and gross beta activities are detected. The ash content is 7.53- 15.95% in the species investigated. Among the algal phyla it is about 13.13% in green algae, 12.77% in brown algae, and 10.77% in red algae on an average. On the other hand, gross alpha activities fluctuate from 180.0 pCi/Kg to 1082.6 pCi /Kg-fresh material experimented, and are 530.72 pCi/Kg on an average. They increase from green to red and brown algae, in turn. The activities in a single species collected at the same season increse from eastern to western and southern coasts of Korea, in turn. Gross beta activities, however, fluctuate from 2.40 nCi/Kg to 22.14 nCi/Kg-fresh material experimented, and 9.03 nCi/Kg on an average. They increase also from green to red nd brown algae, in turn. The gross beta activities are specially higher in Sargassum thunbergii, 22.14 nCi/Kg It is expected that this plant could be an indicator to detect the activities in the marine algae along the coast of Korea.

• Journal of Korean Clinical Nursing Research
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• v.18 no.3
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• pp.329-340
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• 2012

Purpose: This study was done to identify internal marketing activity, emotional labor and work-family conflict that influence turn-over in hospital nurses. Methods: Participants were 513 nurses from 2 general hospitals in Chung-nam and Gyeonggi Provinces, South Korea. Data were collected from September 1 to 30, 2011 using self-report questionnaires. Stepwise multiple regression was used to identify association between variables. Results: The mean score for internal marketing activity was $94.7{\pm}14.7$, emotional labor, $31.4{\pm}5.5$, work-family conflict, $19.6{\pm}4.1$, and turn-over, $13.7{\pm}3.4$. After adjusting for general characteristics, stepwise multiple regression showed that work-family conflict (${\beta}=.20$, p<.001), marketing activity (${\beta}=-.21$, p<.001), and emotional labor (${\beta}=.22$, p<.001) were associated with turn-over. These predictors accounted for 33% of variance in turn-over. Conclusion: The results of this study show that work-family conflict was the most influential predictor indicating a need for the development of strategies to reduce work-family conflict and emotional labor. At the same time internal marketing activity should be supported in the hospital by analyzing the needs for nurses. Also career development programs and mentor systems will be useful for effective manpower management and quality improvement of nursing services.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.342.2-342.2
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• 2002

The ${\beta}$-turn has been implicated as an important conformation for biological recognition of peptides or proteins. Benzodiazepine classes have been known as one of the non peptide ${\beta}$-turn mimic scaffolds. We have developed an efficient approach for the synthesis and derivatization of a scaffold of hydroxytetrahydrodizepinone class in order to screen compound library in various protein targets for new lead generations as well as for structure activity relationships of the scaffold. (omitted)

• Proceedings of the Korean Biophysical Society Conference
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• 1996.07a
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• pp.28-28
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• 1996

NMR studies on the structure of the luteinizing hormone releasing hormone (LHRH) in aqueous buffer and trifluoroethanol (TFE)/aqueous buffer (1:1, v/v) solution were performed. The NMR data under these conditions suggested a unique conformation which includes a ${\beta}$-1 turn of the Tyr5-Arg8 segment and an unusual turn of Ser4-Gly6 segment staggered with the ${\beta}$-I turn. (omitted)

• BMB Reports
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• v.33 no.1
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• pp.49-53
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• 2000

PMAP-23 is a 23-residue antimicrobial peptide derived from porcine myloid cells. In order to investigate the effects of two Pro residues at positions 12 and 15 of PMAP-23 on antibiotic activity, two analogues in which Ala was substituted for Pro residue at position 12 or 15 were synthesized. $Pro^{12}{\rightarrow}Ala$ (PMAPl) or $Pro^{15}{\rightarrow}Ala$(PMAP2) substitution in PMAP-23 caused a significant reduction on antitumor and phospholipid vesicle-disrupting activities, but did not cause a significant effect on antibacterial activity. PMAP-23 displayed the type I ${\beta}-turn$ structure with a negative ellipticity at near 205 om in SDS micelle, whereas PMAP1 and PMAP2 had a somewhat ${\alpha}-helical$ propensity in TFE solution, as compared to PMAP-23. These results suggest that two Pro residues of positions 12 and 15 in PMAP-23 play important roles in the formation of ${\beta}-turn$ structure on lipid membrane and its ${\beta}-turn$ structure may be essential for antibiotic activity including phospholipid vesicle-disrupting property.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.142.1-142.1
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• 2003

Excessive accumulation of beta-amyloid (A$\beta$) peptides is one of the leading hypotheses to explain neurodegenerative processes in Alzheimer's disease (AD). It has been suggested that $A\beta$ toxicity is associated with increases in reactive oxygen species. whose overproduction may in turn initiate neurotoxic events. (omitted)

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.4
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• pp.607-612
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• 1994

The static and dynamic model of IGBT for the SPICE simulation has been successfully developed. The various circuit model parameters are extracted from the I-V and C-V characteristics of IGBT and implemented into our model. The static model of IGBT consists of the MOSFET, bipolar transistor and series resistance. The parameters to be extracted are the threshold voltage of MOSFET, current gain $\beta$ of bipolar transistor, and the series resistance. They can be extracted from the measured I-V characteristics curve. The C-V characteristics between the terminals are very important parameters to determine the turn-on and turn-off waveform. Especially, voltage dependent capacitance are polynomially approximated to obtain the exact turn-on and turn-off waveforms. The SPICE simulation results employing new model agree well with the experimental values.