• Korea-Australia Rheology Journal
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• 제20권4호
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• pp.213-220
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• 2008

The effects of temperature on the rheological properties of the solutions of poly(vinylidene fluoride-co-hexafluopropylene) (PVDF-HFP) in dimethyl acetamide (DMAc) were investigated in terms of frequency and concentration. The effects of temperature on the intrinsic viscosity of the solutions were discussed. In dynamic rheological measurement, the concentrated solutions showed a little unexpected rheological response; as temperature was increased dynamic viscosity was increased and the solutions exhibited more noticeable Bingham body character over the temperature range, 30 to $70^{\circ}C$. In addition, the solution gave longer relaxation time, lower value of loss tangent and higher value of yield stress at higher temperature and at higher concentration. On the other hand, the dilute solutions revealed that intrinsic viscosity was decreased and its Huggins constant was increased with increasing temperature. These physical parameters suggested that the increase of viscosity with increasing temperature resulted from the localized gelation of PVDF-HFP due to reduced solubility to the solvent.

• 한국수산과학회지
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• 제56권5호
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• pp.651-659
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• 2023

The effect of bio-logger tagging location on blood characteristics and bio-logger attachment efficiency in spotted sea bass (mean body weight 2356.7 g) was investigated. The fish were tagged at four different tagging locations: no-tag (control), operculum attachment (OA), dorsal muscle attachment (DA), and cauda peduncle muscle attachment (CA). The blood properties and bio-logger attachment efficiencies were examined on days 1, 7, 14, and 35 after tagging the bio-logger at each tagging location. During the experimental periods, the concentrations of hematocrit and hemoglobin in whole blood, and GOT (glutamic oxaloacetic transaminase), GPT (glutamic pyruvic transaminase), total protein (TP), glucose, total cholesterol, cortisol, and superoxide dismutase in plasma were not affected by the attachment location of the bio-logger, however, the TP concentration was significantly lower in OA than in the control group on day 7. After tagging for 35 days, the efficiencies of bio-logger attachment in the OA, DA, and CA after tagging for 35 days were 33.3%, 100.0%, and 33.3%, respectively. These results indicate that, in our experimental condition, the most appropriate bio-logger attachment location is DA, providing basic information on bio-logger utilization methods for ecological and biological biotelemetry surveys of the spotted sea bass.

• 한국작물학회지
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• 제57권4호
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• pp.324-330
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• 2012

In this study, ${\beta}$-carotene concentrations was determined in soybean cultivar according to seed size, usage, seed coat color and cotyledon color as well as the process of seed germination. The total average concentration of ${\beta}$-carotene was $6.6{\mu}g/g$ in soybean seed, $33.3{\mu}g/g$ in soybean sprout. According to seed size, the total ${\beta}$-carotene concentration of soybean was $6.9{\mu}g/g$ in large soybean seed, $6.7{\mu}g/g$ in medium soybean seed, and $6.31{\mu}g/g$ in small soybean seed. In soybean sprout, the total ${\beta}$-carotene concentration was $21.4{\mu}g/g$ in large soybean sprout, $30.5{\mu}g/g$ in medium soybean sprout, and $43.5{\mu}g/g$ in small soybean sprout. According to the utilization of seed, the total ${\beta}$-carotene concentration of soybean seed was $7.2{\mu}g/g$ in cooked with rice soybean seed, $6.1{\mu}g/g$ in paste and curd soybean seed, and $6.3{\mu}g/g$ in sprout soybean seed. In soybean sprout, the total ${\beta}$-carotene concentration was $25.9{\mu}g/g$ in cooked with rice soybean sprout, $32.4{\mu}g/g$ in paste and curd soybean sprout, and $41.9{\mu}g/g$ in sprout soybean sprout. When comparison with seed coat color, the total ${\beta}$-carotene concentration of soybean with brown seed coat ($8.8{\mu}g/g$) was slightly higher than those of soybean with yellow ($6.1{\mu}g/g$). In soybean sprout, the total ${\beta}$-carotene concentration was $21.8{\mu}g/g$ in black seed coat sprout, $38.7{\mu}g/g$ in brown seed coat sprout, $34.1{\mu}g/g$ in green seed coat sprout, $39.5{\mu}g/g$ in yellow seed coat sprout, and $30.5{\mu}g/g$ in mottle seed coat sprout. The results of this study suggested the functional characteristics of soybean through quantitative analysis of ${\beta}$-carotene.

• 농업과학연구
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• 제43권1호
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• pp.100-108
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• 2016

An auxin-producing bacteria (strain 5-1) was isolated from button mushroom compost in Boryeong-Si, Chungcheongnam-Do. The 5-1 strain was classified as a novel strain of Enterobacter aerogenes based on chemotaxonomic and phylogenetic analyses. The isolated E. aerogenes 5-1 was confirmed to produce indole-3-acetic acid (IAA), one of the auxin hormones, using TLC and HPLC analyses. When the concentration of IAA was assessed by performing HPLC quantitative analysis, a maximum concentration of IAA of $109.9mgL^{-1}$ was detected in the culture broth incubated in R2A medium containing 0.1% L-tryptophan for 24 h at $35^{\circ}C$. Acidification of the culture was deemed caused by an increase of IAA because a negative relationship between IAA production and pH was observed. Supplementation with a known precursor of IAA production, L-tryptophan, appeared to induce maximal production at 0.1% concentration, but it reduced production at concentrations above 0.2%. To investigate the growth-promoting effects to crops, the culture broth of E. aerogenes 5-1 was used to inoculate water cultures and seed pots of mung bean and lettuce. In consequence, adventitious root induction and root growth of mung bean and lettuce were two times higher than those of the control.

• 한국토양비료학회지
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• 제50권4호
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• pp.285-292
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• 2017

Antibiotics have been used for treating human and animal disease and enhancing growth of cattle, swine, and poultries. However, overused antibiotics can be released into the environment and produce antibiotic resistance genes (ARGs) in the environment. Main objective of this research was to monitor residual of antibiotics in solid matrix such as manure, wastewater sludge, soil and sediment. Total of six antibiotics, Chlortetracycline (CTC), Oxytetracycline (OTC), Tetracycline (TC), Sulfamethazine (SMT), Sulfamethoxazole (SMX), Sulfathiazole (STZ), used for both human and animal was monitored. Result showed that the detection frequency of 6 antibiotics was ordered SMT (100%) > TC = CTC (75%) > OTC (38%) > STZ (13%) > SMZ (0%) and the highest concentration ($309.83{\mu}g\;kg^{-1}$, SMT) was observed in manure. Comparing residual concentration of antibiotics (TC, CTC, and OTC) in soil and sediment, higher concentration was observed in sediment indicating that dissolved forms of antibiotics are released into river and sorbed into sediment particle. In conclusion, monitoring for residual of antibiotics in the environment is necessary and more research should be conducted to verify the source of antibiotic release.

• 한국물환경학회지
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• 제22권1호
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• pp.45-50
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• 2006

This study was performed to evaluate the air lift reactors (ALR) by variations of HRT and recycling rate. Air lift reactor was composed of bioreactor and clarifier above it. To remove organic matters and nitrogen through the formation of microbic film and filtration, bio-filter reactors were filled with clay, glass, bead, waste plastic, respectively. Influent wastewater was fed to biofilter reactor, and effluent wastewater from bio-filter reactor was injected ALR again, instead of adding external carbon source. Effluent BOD concentration was satisfied with lower than 10 mg/L in recycling rate 100% regardless of the variation of HRT and the kinds of media materials. In HRT 4 hr, recycling rate 100%, BOD removal efficiency rate was from about 85 to 90%, COD removal efficiency rate was higher than 90%. Effluent TN concentration was satisfied with less than 20 mg/L, if HRT was maintained by over than 6 hr regardless of recycling rate and media materials. Over than HRT was 4 hr, microbes concentration in air lift reactor was maintained over than 2,500 mg/L constantly, not sensitive to environmental condition, and organic removal was effective as it was higher.

• 접착 및 계면
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• 제4권3호
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• pp.14-20
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• 2003

UV 경화에 사용되는 poly(ethylene glycol 400) dimethacrylate(PEGA400DMA)와 ethylene glycol dimethacrylate(EGDMA)를 사용하여 모노머(monomer)의 종류에 따른 경화거동과 광개시제의 양과 온도에 따른 경화 거동을 photo-DSC를 사용하여 살펴보았다. Ethylene glycol의 단위길이가 늘어날수록, 광개시제의 양이 증가할수록, 반응 온도가 높을수록 경화속도가 빠르게 일어났다. 또한 PEG400DMA의 반응속도가 EGDMA보다 느리게 나타났지만 전환률은 높게 나타남을 알 수 있었다.

• 농업과학연구
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• 제49권2호
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• pp.331-339
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• 2022

Deforestation and conservation of coniferous forest have been recognized as critical issues in Korea due to climate change. The main purpose of this research was to monitor changes of secondary metabolite contents and growth of Korean fir (Abies koreana) according to the temperature change in Mt. Halla. The Korean fir located at three different regions, Yeongsil, Witseoreum, and Jindallaebat, was monitored in April, July, and October from 2016 to 2018 and secondary metabolites, specifically lutein, α-carotenoid, and β-carotenoid, were analysed with high performance liquid chromatography. The results showed that average concentrations of lutein, α-carotenoid, and β-carotenoid were 0.82 - 23.30, 0.02 - 2.01, and 0.11 - 2.84 ㎍·g-1 and the highest concentration of secondary metabolite was observed in October compared to April and July. The average length and width of Korean fir in the three regions were 11.84 - 20.70 and 1.78 - 2.41 mm from 2016 - 2018. A correlation analysis showed that the concentrations of all three secondary metabolites were negatively correlated with temperature and a significant difference was observed between temperature and lutein concentration in Korean fir. Overall, growth and production of secondary metabolites in Korean fir highly depended on the temperature, and global warming thus might have an adverse effect on the growth and physiological changes of Korean fir in Mt. Halla.

• Biotechnology and Bioprocess Engineering:BBE
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• 제7권6호
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• pp.371-374
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• 2002

Production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)［P(3HB/V)］, by fed-batch culture of recombinant Escherichia coli harboring a plasmid containing the Alcaligenes latus polyhy-droxyalkanoate (PHA) biosynthesis genes, was examined in two pilot-scale fermentors with air supply only, In a 30 L fermentor having a XLa value of 0.11 S­$^1$, the final P(3HB/V) concentration and the P(3HB/V) content obtained were 29.6 g/L and 70.1 wt%, respectively giving a productivity of 1.37 g P(3HB/V)/L-h. In a 300 L fermentor having a XLa of 0.03 S­$^1$, the P(3HB/V) concentration and the P(3HB/V) content were 20.4 g/L and 69 wt%, respectively giving a productivity of 1.06g P(3HB/V)/L-h. These results suggest that economical production of P(3HB/V) is possible by fed-batch culture of recombinant E. coli in a large-scale fermentor having low KLa value.

• KSBB Journal
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• 제26권6호
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• pp.483-490
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• 2011

Bioactive peptides (BAP) showed excellent cosmetic activity than bio-materials such as caffeic acid (CA), gallic acid (GA), and nicotinic acid (NA). Caffeoyl tripeptide-1 (CT-1) is a BAP that is stabilized with Gly-His-Lys (GHK) tripeptide and CA by using Fmoc solid phase peptide synthesis. Digalloyl tetrapeptide-19 (DT-19) is stabilized by combining Lys-Glu-Cys-Gly with GA and nicotinoyl tripeptide-1 (NT-1) is synthesized by GHK and NA. According to experiments, CT-1 has an excellent anti-oxidant function even with a very small amount of 10 ppm CT-1. DT-19's tyrosinase inhibition activity has the better effect of about 28.57% in 0.01% and 33.33% in 0.005% of concentration and about 7.89% in 0.001% concentration than vitamin-C. In addition, NT-1 is safer than the NA. Almost BAPs like pal-KTTKS, acetyl hexapeptide, and copper tripeptide-1 have the anti-wrinkle effect while DT-19 and NT-1 are applicable for potential BAPs focused on the whitening effect. The three kinds of BAPs like CT-1, DT-19, and NT-1 consisting of amino acids are safe to the skin, and have more excellent stability than bio-materials which are found to be unstable and cause skin irritation. Due to the high biological activity of BAP in the field of skin care, its utilization will increase constantly.