• KSBB Journal
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• v.14 no.3
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• pp.303-308
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• 1999

An in vitro culture method for entomopathogenic nematode Steinernema glaseri was developed. A symbiotic bacterium was isolated from Steinernema glaseri and identified as Xenorhabdus nematophilus. Phase variation that differed in some biochemical characteristics of symbiotic bacterium was observed. Entomopathogenic nematodes carried only phase I bacterium in their guts. Phase I bacterium could be converted into phase II form in in vitro culture medium consisting of 5% yeast extract, 0.5% NaCl, 0.05% $K_2HPO_4$, $0.02% MgSO_4$.$7H_2O$. The optimum temperature for bacterial growth was $28^{\circ}C$. The pH of the culture medium increased up to 9.0-9.5 during the exponential growth period of the culture, regardless of initial pH 6-7. Various culture media such as chicken offal, dog food, bovine liver, peanut, and so on were tested for in vitro culture of the nematodes. The best medium for Steinernema glaseri production was obtained from concentrated homogenate of bovine liver and the nematode growth was highest at 80% bovine liver. In the co-culture of entomopathogenic nematode with its symbiont, the growth rate of nematodes was 2 times faster than that without its symbiont and the nematode concentration reached about $5.5\times10^4$/mL within 15 days.

• Food Science of Animal Resources
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• v.28 no.3
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• pp.251-255
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• 2008

This study was conducted to determine the effects of dietary supplementation with CLA (0, 0.5, 1.0, 1.5, and 2.0%) on the proximate composition, sensory evaluation, pH, TBARS, cooking loss, WHC, shear force and objective color of chicken meat. Two hundred broiler chickens (Arbor Acre Broiler, male) were randomly assigned to five groups, fed for five weeks, and slaughtered. The proximate composition and crude protein of thigh muscle from the 1.5% and 2.0% CLA groups were significantly higher than the other groups (p<0.05), however there was no difference in moisture, crude fat, and crude ash. Based on sensory evaluation, tenderness, juiciness, and flavor were not significantly different among the treatment groups. The pH of thigh muscle from the CLA treated groups was higher than the control, and significantly increased with the increasing levels of CLA in the broiler diets (p<0.05). TBARS values were significantly lower in the CLA treated groups, and decreased with increasing CLA levels in the diet (p<0.05). Therefore, CLA may improve the shelf life of chicken meat. WHC, shear force, and meat color did not show any significant variation in this study. In conclusion, the accumulation of CLA and the production of fresh chicken meat without changes in meat quality can be achieved through supplementation with 2% CLA. Accumulation of CLA in chicken meat significantly increased with increasing CLA levels in the diet.

• Clinical and Experimental Pediatrics
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• v.50 no.6
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• pp.576-579
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• 2007

The syndrome of resistance to thyroid hormone (RTH) is characterized by reduced tissue sensitivity to thyroid hormone (TH). In the majority of subjects, RTH is caused by mutations in the thyroid hormone receptor beta ($TR{\beta}$) gene, located on the chromosome locus 3p24.3. RTH is inherited in an autosomal dominant manner. The clinical presentation of RTH is variable, but common features include elevated serum levels of thyroid hormone (TH), a normal or slightly increased thyrotropin (thyroid stimulating hormone, TSH) level that responds to thyrotropin releasing hormone (TRH), and goiter. We report a 4 year-old girl, who was clinically euthyroid in spite of high total and free $T_4$, and $T_3$ concentrations, while TSH was slightly increased. Sequence analysis of the thyroid hormone receptor beta gene (THRB) confirmed a heterozygous C to T change at nucleotide number 1303, resulting in a substitution of histidine by tyrosine at codon 435 (H435Y). Further analysis of her parents revealed that the H435Y variation was a de novo mutation since neither parents had the variation. Her parents' TH and TSH levels were within normal range.

• Journal of Environmental Science International
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• v.11 no.6
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• pp.529-535
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• 2002

Efffcts of physico-chemical factors on the zonation and vertical distribution of benthic microalgal communities in the tidal flats of Youngkwang and Canaiin, Korea, were studied. Concentrations of nutrients were low throughout the study period. A 38 species of benthic microaigae was identified. Most of the algae were pennate diatoms with small size. Cell numbers at silty sediments were higher than sandy sediments, and showed high patchy distribution. Zonal distributions of benthic microalgae showed higher variation from silty sediment than sandy sediments. Benthic microalgae showed vertical migration within the upper few mm of sediment with periodicity closely related to tidal cycles. Maximum cells were observed from 0 mm depth both sandy and silty sediments. Cells of benthic microalgae in the 1 - 2 mm depth decreased after desiccation of sediments. The variation of cells was higher at sandy sediments than silty sediments. Cell numbers of benthic microalgae showed no positive relationships with pH and nutrinets except NH$_4$-N.

• Structural Engineering and Mechanics
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• v.23 no.3
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• pp.233-247
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• 2006

Most codes of practice state that for large in-plane structures it is necessary to account for the spatial variability of earthquake ground motion. There are essentially three effects that contribute for this variation: (i) wave passage effect, due to finite propagation velocity; (ii) incoherence effect, due to differences in superposition of waves; and (iii) the local site amplification due to spatial variation in geological conditions. This paper discusses the procedures to be undertaken in the time domain analysis of a cable-stayed bridge under spatial variability of earthquake ground motion. The artificial synthesis of correlated displacements series that simulate the earthquake load is discussed first. Next, it is described the 3D model of the International Guadiana Bridge used for running tests with seismic analysis. A comparison of the effects produced by seismic waves with different apparent propagation velocities and different geological conditions is undertaken. The results in this study show that the differences between the analysis with and without spatial variability of earthquake ground motion can be important for some displacements and internal forces, especially those influenced by symmetric modes.

• Korean Journal of Pharmacognosy
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• v.17 no.2
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• pp.123-128
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• 1986

The determination of berberine in Berberis koreana was examined by the high performance liquid chromatography using ${\mu}-Bondapak$ $C_{18}$ column and $CH_3CN/phosphate$ buffer (pH 5.2) (60/40) as a mobile phase. The seasonal variations of berberine contents in Berberis koreana were as follows; 1) In roots, the average berberine content was 0.94% with the highest level of 1.32% in October. 2) In stems, their average berberine content was about 0.1% and in March, April, October and November, the contents were relatively high. 3) In leaves, however, the content was as low as 0.005%. According to the experimental results obtained, we found that Berberis koreana roots can serve as the useful natural plant resources for the berberine and October is the optimal season for the collection.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.4
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• pp.243-251
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• 2012

Real-time monitoring for environmental factors(temperature, salinity, chlorophyll, etc.) and carbonate components( pH and $fCO_2$) was conducted during 5-6th of July, 2012 at a seaweeds farm in Gijang, Busan. Surface temperature and salinity were ranged from $12.5{\sim}17.6^{\circ}C$ and 33.7~34.0, respectively, with highly daily and inter-daily variations due to tide, light frequency(day and night) and currents. Surface $fCO_2$ and pH showed a range of $381{\sim}402{\mu}atm$ and 8.03~8.15, and chlorophyll-a concentration in surface seawater ranged 0.8~5.8 ${\mu}g\;L^{-1}$. Environmental and carbonate factors showed the highest/lowest values around 5 pm of 5th July when the lowest tidal height and strongest thermocline in the water column, suggesting that biological production resulted in decrease of $CO_2$ and increase of pH in the seaweed farm. Processes affecting the surface $fCO_2$ distribution were evaluated using a simple budget model. In day time, biological productions by phytoplankton and macro algae are the main factors for $CO_2$ drawdown and counteracted the amount of $CO_2$ increase by temperature and air-sea exchange. The model values were a little higher than observed values in night time due to the over-estimation of physical mixing. The model suggested that algal production accounted about 14-40% of total $CO_2$ variation in seaweed farm.

• KSBB Journal
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• v.11 no.3
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• pp.303-310
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• 1996

The marine microalga Isochrysis galbana Parke was studied to optimize its growth conditions in flask culture. Important medium components studied include nitrogen source, buffer, trace elements and vitamins. Environmental conditions include pH, temperature, light intensity, mixing extent and working volume. The medium prepared from natural sea-waters gave a higher final cell density than the medium prepared from synthetic sea-water Nitrate was a better source than ammonium. In the range of 0.4∼2mM, the final cell density was proportional to the initial nitrate concentration and the cell yield was estimated to be 8.5g dry cell wt/g N. For phosphate, optimal growth was observed in 0.1∼1.0mM but a considerable variation in pH was resulted. The addition of Tris at 5mM or 7mM could stabilize the medium pH, but this significantly reduced both growth rate and final cell density, The effect of trace elements and vitamins was negligible. Optimal temperature and initial pH were $20^{\circ}C$ and 8. When the intensity of incident light was varied in the range of 400∼2100 lux, the growth rate increased from 10mL to 70mL, the final cell density decreased although the initial growth rate did not change. Optimal agitation speed was 100rpm when working volume was 30mL. With optimal conditions, the maximum specific growth rate obtained was 0.021hr-1 and the final cell density was 1.1g/L.

• Korean Journal of Environmental Agriculture
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• v.18 no.2
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• pp.169-173
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• 1999

To investigate the chemical properties of rainwater in the southern part of gyeonggi Province, the rainwater was collected in Suwon and Ansung for six months from May to October in 1998, and analyzed its chemical composition. The ion balance and electric conductivity balance showed confidence to chemical analyses of rainwater. The most frequent pH range of rainwater was pH $5.0{\sim}5.6$ both in Suwon and Ansung area with distribution ratio of 37.9% and 35.3%, respectively. Among the 1mm fraction for initial 5mm of rainfall, ion concentration of initial rainwater (less than 1mm of rainfall) was higher than those of the later terms. The major ions in rainwater were $NH_4^-,\;Ca^{2+}$and $Na^+$ for cations, and $SO_4^{2-}$ and $NO_3^-$ for anions. Monthly variation of pH of rainwater showed low level of 4.2 to 4.5 in Suwon and 4.6 to 4.7 in Ansung in August and September, respectively. The $nss-SO_4^{2-}/NO_3^-$ ratio of rainwater in Suwon and Ansung area were 2.2 and 2.9 which means nonsea salt $SO_4^{2-}$ contrbuted to acidity of rainwater more in Ansung than Suwon area.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.5
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• pp.495-500
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• 2014

We examined chemical changes in oysters Crassostrea gigas and packing water that were sold after storage at 5, 10, and $20^{\circ}C$. The pH of oysters stored at $5^{\circ}C$ dropped to 5.81 after 10 days of storage, while that of oysters at $10^{\circ}C$ and $20^{\circ}C$ dropped to 5.37 after 8 days and to 5.04 after 4 days, respectively. The glycogen content of oysters stored at $5^{\circ}C$ decreased from 718.89 to 421.85 mg/100g during storage, while that of oysters at $10^{\circ}C$ decreased to 351.49 mg/100 g after 4 days. The turbidity and soluble protein in packing water increased slightly. The viable cell count of oysters did not exceed 6 log CFU/g after 10 days of storage at $5^{\circ}C$, but that of oysters at $10^{\circ}C$ did so after 8 days. Additionally, the viable cell count of packing water was lower than that of oysters. We performed a principal component analysis, where the first principal component (55.03%-57.24%) and second principal component (42.76%-44.97%) described most variation. The first principal component included the pH of oysters and packing water, and the glycogen content of oysters. A Pearson correlation between the first two principal components had a higher R value than that between other components. Freshness was evaluated using the pH of oysters and packing water, and glycogen. We found that soluble protein content was significantly associated with a lower pH and glycogen content.