• Fisheries and Aquatic Sciences
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• 제18권1호
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• pp.45-50
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• 2015

A 10-day trial was conducted to evaluate the salinity tolerance and hematological responses of juvenile ship sturgeon Acipenser nudiventris under different salinity levels. A total of 240 fish averaging $6.2{\pm}0.13g$ (mean${\pm}$SD) were randomly distributed into 12 tanks in groups of 20, and each tank was then randomly assigned to one of three replicates of four different salinities at 0, 4, 8 and 12‰. At the end of 10 days of experimental period, plasma protein value of fish exposed to 0‰ and 4‰ salinities was significantly higher than those of fish exposed to 8‰ and 12‰ salinities (P < 0.05). Significantly higher values for plasma cortisol and glucose were obtained in fish exposed to 12‰ salinity compared to the fish exposed to 0‰ and 4‰ salinities (P < 0.05). Plasma potassium and sodium values increased significantly by increment of salinity levels (P < 0.05). Therefore, these results indicated that in natural environments, juvenile ship sturgeon, A. nudiventris in migratory populations could be able to migrate and adjust successfully into brackish water with a salinity of up to 8‰ without any short-term hematological stress responses.

• Bulletin of the Korean Chemical Society
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• 제31권9호
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• pp.2509-2513
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• 2010

In order to increase protease stability of a novel Trp-rich model antimicrobial peptide, $K_6L_2W_3$ (KLWKKWKKWLK-$NH_2$)and investigate the effect of L-amino acid to peptoid residue conversion on biological functions, we synthesized its antimicrobial peptoid, $k_6l_2w_3$. Peptoid $k_6l_2w_3$ had similar bacterial selectivity compared to peptide $k_66L_2W_3$. The bactericidal rate of $k_6l_2w_3$ was somewhat slower than that of $K_6L_2W_3$. Peptoid $k_6l_2w_3$ exhibited very little dye leakage from bacterial outer-membrane mimicking PE/PG liposomes, as observed in $K_6L_2W_3$, indicating that the major target site of $K_6L_2W_3$ and $k_6l_2w_3$ may be not the cell membrane but the cytoplasm of bacteria. Trypsin treatment of $K_6L_2W_3$ completely abolished antimicrobial activities against Escherichia coli and Staphylococcus aureus. In contrast, the antimicrobial activity of $k_6l_2w_3$ was completely preserved after trypsin treatment. Taken together, our results suggested that antimicrobial peptoid $k_6l_2w_3$ can potentially serves as a promising therapeutic agent for the treatment of microbial infection.

• Journal of the Korean Wood Science and Technology
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• 제33권4호통권132호
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• pp.15-22
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• 2005

현악기용 도료가 현악기의 음향성능에 미치는 영향을 조사하기 위해 음향분석장치(FFT)와 점탄성 분석장치(DMTA, dynamic mechanic thermal analyzer)를 이용하여 목재악기용 도료의 음향적 성능을 평가하였다. 목재악기용으로 사용된 도료는 악기용 우레탄계 상도도료, 오일 스테인계 도료, 천연바니쉬, 캐슈 도료 및 자외선 경화형 에폭시 도료를 사용하였다. 형성된 도막의 음향적인 특성은 FFT 분석기에서 측정된 공명주파수와 댐핑값(damping factor)과 DMTA에서 측정된 tan ${\delta}$를 통하여 유추하였다. FFT에서 측정된 공명주파수와 댐핑값으로부터 도막이 가지는 음향특성에 대해 분석하였다. 측정된 도막의 점탄성적인 특성과 음향적 특성을 검토한 결과 악기용으로서의 적정도료를 결정하였다.

• Fisheries and Aquatic Sciences
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• 제17권4호
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• pp.391-401
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• 2014

Ten feeding trials were conducted to determine and to make the guideline for the optimum feeding rates in olive flounder Paralichthys olivaceus fed extruded pellets at various growth stages at the optimum rearing water temperature. The entire trials were grouped into four growth stages, namely the first stage of juvenile (5 and 9 g), the second stage of juvenile (20, 30, 40 and 50 g), growing (240 and 317 g) and sub-adult (384 and 525 g) stages with 2, 4, 2 and 2 feeding trials, respectively. In the first and second experiments, results indicated that the optimum feeding rates for the first stage of juvenile olive flounder weighing 5 and 9 g could be >5.17 but <5.52% and >4.44 but <4.64% body weight (BW)/day, respectively. In the third, fourth, fifth and sixth experiments, results suggested that the optimum feeding rates for the second stage of juvenile olive flounder weighing 20, 30, 40 and 50 g could be >3.47 but <3.50, >2.85 but <3.53, >2.58 but <3.04 and >2.36 but <2.50% BW/day, respectively. In the seventh and eighth experiments, results showed the optimum feeding rates for growing olive flounder weighing 240 and 317 g to be >1.03 but <1.25 and >0.85 but <1.0 % BW/day, respectively. In the ninth and tenth experiments, the optimum feeding rates in sub-adult olive flounder weighing 384 and 525 g were shown to be >0.69 but <0.7 and >0.55 but <0.8% BW/day, respectively. We will compare these results with the previous studies done by other research groups.

• Journal of Microbiology and Biotechnology
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• 제9권5호
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• pp.576-581
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• 1999

Effects of signal sequences, protein sizes and dissolved oxygen on the secretion of human lysozyme from a recombinant yeast were experimentally characterized. The systems consisted of Saccharomyces cerevisiae host SEY2102 that was transformed with two different plasmids. These plasmids were identical with an exception to the plasmid pMC614, which contained the native yeast MFα1 sequence and the plasmid pMC632 with the non-native rat α-amylase signal sequence. The expression of human lysozyme was controlled by the ADHI promoter. The native yeast MFαl signal sequence was more efficient than the non-native rat α-amylase signal sequence in directing the secretion of human lysozyme. Lysozyme secreted with the α-amylase signal was retained inside the cells and released to the medium very slowly, thereby causing a lower cell growth rate and a decreased product secretion rate. Lysozyme was secreted more efficiently than invertase, which is an order of magnitude bigger in molecular size compared to lysozyme, which was under the direction of the MFαl signal sequence, suggesting that protein sizes may affect the secretion efficiency. When expressed in anaerobic conditions in the medium where the ADHI promoter was derepressed, the amount of lysozyme secreted was about twice higher than that of the aerobic culture. However, the secretion rates were identical. This result showed that the dissolved oxygen level may affect the efficiency of protein secretion only, and not the secretion rate of the product protein.

• Asian-Australasian Journal of Animal Sciences
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• 제28권4호
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• pp.551-558
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• 2015

This study was carried out to evaluate the dietary threonine requirement by measuring the plasma free threonine and ammonia concentrations in rainbow trout, Oncorhynchus mykiss after dorsal aorta cannulation. A total of 70 fish (average initial weight $506{\pm}8.2g$) were randomly distributed into each of the 14 net cages (5 fish/cage). After 48 hours (h) of feed deprivation, each group was intubated at 1% body weight with one of the seven L-amino acid based diets containing graded levels of threonine (0.42%, 0.72%, 0.92%, 1.12%, 1.32%, 1.52%, or 1.82% of diet, dry matter basis). Blood samples were taken at 0, 5, and 24 h after intubation. Post-prandial plasma free threonine concentrations (PPthr) of fish 5 h after intubation with diets containing 1.32% or more threonine were significantly higher than those of fish intubated with diets containing 1.12% or less threonine (p<0.05). Post-absorptive free threonine concentrations (PAthr) after 24 h of intubation of the fish with diets containing 0.92% or more threonine were significantly higher than those of fish intubated with diets containing 0.72% or less threonine. Post-prandial plasma ammonia concentrations (PPA, 5 h after intubation) were not significantly different among fish intubated with diets containing 1.12% or less threonine, except the PPA of fish intubated with diet containing 0.42% threonine. Broken-line model analyses of PPthr, PAthr, and PPA indicated that the dietary threonine requirement of rainbow trout should be between 0.95% (2.71) and 1.07% (3.06) of diet (% of dietary protein on a dry matter basis).

• 한국수산과학회지
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• 제51권1호
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• pp.95-106
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• 2018

To evaluate appropriate reference genes for the normalization of quantitative reverse transcription PCR (RT-qPCR) data with embryonic and larval samples from Russian sturgeon Acipenser gueldenstaedtii, the expression stability of eight candidate housekeeping genes, including beta-actin (ACTB), elongation factor-1A (EF1A), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), histone 2A (H2A), ribosomal protein L5 (RPL5), ribosomal protein L7 (RPL7), succinate dehydrogenase (SDHA), and ubiquitin-conjugating enzyme E2 (UBE2A), were tested using embryonic samples from 12 developmental stages and larval samples from 11 ontogenic stages. Based on the stability rankings from three statistic software packages, geNorm, NormFinder, and BestKeeper, the expression stability of the embryonic subset was ranked as UBE2A>H2A>SDHA>GAPDH>RPL5>EF1A>ACTB>RPL7. On the other hand, the ranking in the larval subset was determined as UBE2A>GAPDH>SDHA>RPL5>RPL7>H2A>EF1A>AC TB. When the two subsets were combined, the overall ranking was UBE2A>SDHA>H2A>RPL5>GAPDH>EF1A>ACTB>RPL7. Taken together, our data suggest that UBE2A and SDHA are recommended as suitable references for developmental and ontogenic samples of this sturgeon species, whereas traditional housekeepers such as ACTB and GAPDH may not be suitable candidates.

• 펄프종이기술
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• 제45권2호
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• pp.1-12
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• 2013

The annals of Joseon Dynasty designated as a national treasure No. 151 and a UNESCO World Memory are among the greatest archives that should be preserved permanently and inherited to future generations through the proven scientific conservation method. The annals of Joseon Dynasty in the custody of the National Archives of Korea as the sole original archive, has been restricted from the direct physical and chemical approaches. In this study, it is to develop a systematic conservation management scheme, based on the conservation state of the annals. Four books from the annals were selected out of 848 books and their moisture contents and optical property profiles were measured through the books. All the defects previously and newly found were pictured in 10~100 magnifications. The wire marks left on the Hanji's of the annals were analyzed. It was found that water damages and paper molds were prevalent in all four annals selected, and it was recommended to conduct more research for the conservation of those damaged areas. It turned out that various qualities of Hanji's were used for the time of publishing the annals because moisture content, optical properties, and wire mark intervals were quite different between papers even within one book.

• 한국산업융합학회 논문집
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• 제23권1호
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• pp.83-91
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• 2020

The evaluation of the compression behavior of the cushioning material is of importance to achieve appropriate packaging design. In order to change packaging design from polymeric-based to more eco-friendly cellulose-based nire effectively, comparative study on the compression behavior between these two packaging materials is crucial. In this study, the stress-strain behavior, hysteresis loss, and response characteristics for cyclic loading were analyzed through compression tests on multi-layered corrugated structure (MLCS) and expanded polystyrene (EPS) packaging materials. MLCS produced in Korea is produced by winding a certain number of single-faced corrugated paperboard, and the compression behavior of this material was turned out to be 6 stages: elastic stage, first buckling stage, sub-buckling stage, densification stage, last buckling stage and high densification stage. On the other hand, EPS's compression behavior was in 3 stages: linear elastic stage, collapse plateau, and densification stage. The strain energy per unit volume (strain energy density) of MLCS did not differ depending on the material thickness, but it showed a clear difference depending on the raw material and flute type. Hysteresis loss of MLCS ranged from 0.90 to 0.93, and there were no significant differences in the raw material and flute type. These values were about 5 to 20% greater than the hysteresis of the EPS (about 0.78 to 0.87).

• International Journal of Industrial Entomology and Biomaterials
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• 제22권1호
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• pp.25-28
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• 2011

The virulence against the two-spotted spider mite, Tetranychus urticae Koch, was evaluated with entomopathogenic fungus Paecilomyces lilacinus (Thom) Samson HY-4 which is isolated from coleopteran insect and registered to Korean and US patents. Virulence tests were conducted with conidial suspensions ($1.5{\times}10^6conidia/ml$) of P. lilacinus HY-4 against T. urticae adults and positive results were recorded in laboratory conditions. The spraying device was also developed for the efficient and exact evaluation of treatment. The developed spraying device was named as SD-tower sprayer and its efficacy of spraying conidia was evaluated. The accumulated mortality caused by P. lilacinus HY-4 using SD-tower spray was about 73% at 6 days after inoculation. This suggest that the isolate P. lilacinus HY-4 may be considered as promising for a new approach to prevent adult infestations by T. urticae.