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- Jin, Young Hoon, et al.
(författare)
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Wavelet decomposition for detection of chaotic characteristics of monthly precipitation at Mokpo, Korea
- 2005
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Ingår i: 31st IAHR Congress 2005 : Water Engineering for the Future, Choices and Challenges - Water Engineering for the Future, Choices and Challenges. - 8987898245 - 9788987898247 ; , s. 429-437
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Konferensbidrag (refereegranskat)abstract
- In the present study, we apply deterministic chaos theory to investigate nonlinear dynamics in monthly precipitation at Mokpo, Korea, after wavelet decomposition. The wavelet transform is used not only for removal of noise but also for extraction of low and high frequency components in the data, representing low-dimensional dynamics. In order to determine an appropriate decomposition level for the wavelet transform, a correlation dimension analysis is applied for the respective low and high frequency signals after successive decomposition. The wavelet decomposition is performed up to 5th-level with orthogonal and compactly supported wavelets. Consequently, a long-term approximation (low frequency) and a short-term detail (high frequency) time series for the monthly precipitation obtained after 5th-level decomposition are investigated in terms of deterministic chaos theory. The data sets with low/high frequency components filtered by the wavelet transform are used for three-dimensional phase space analysis, respectively. Results show that both low and high frequency signals include clear chaotic signals and, therefore, might be governed by underlying dynamics based on different frequencies, respectively.
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| 2. |
- Jo, Ji Song, et al.
(författare)
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Anti-wrinkle activity of beta-carotene extracted & purified from recombinant Escherichia coli
- 2008
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Ingår i: KSBB Journal. - 1225-7117 .- 2288-8268. ; 23:6, s. 513-518
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Tidskriftsartikel (refereegranskat)abstract
- This paper described the extraction/purification of β-carotene from recombinant E.coli and evaluation of anti-wrinkle activity of purified β-carotene. No significant differences in extraction yields were observed when hexane or isobutyl acetate was used. However, extraction from wet-cell cake resulted in 2-fold higher amount of β-carotene than that from dry cells. Disruption of 5 g-wet cells by ultrasonic homogenizer, acetone dehydration, extraction with isobutyl acetate resulted in 36 mg of β-carotene corresponding to 61.2% of recovery. The formation and separation of ββ-carotene crystal improved the purity. 633 mg of β-carotene crystal with 93% purity was obtained from 223 g/L of wet-cell cake harvested from 2.5-L fed-batch culture broth. The cultures of normal human primary fibroblast were performed to investigate the effect of β-carotene on cytotoxicity as MTT assay and anti-wrinkle activity as collagen synthesis assays. 1.7μM of β-carotene was found to be optimal concentration at which 1.4-fold higher amount of collagen was synthesized than that in absence of β-carotene. This indicates that highly purified β-carotene can be obtained from recombinant E.coli by applying simple method with less toxic solvent and can be used in functional cosmetics as anti-wrinkle agent.
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