• Korean Journal of Microbiology
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• v.18 no.1
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• pp.20-28
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• 1980

Thirty species of wild yeasts were ioslated and identified from two hundred strains collected from flowers by enrichment techniques using steptomycin. Among them, twnety three species could assimilate methanol and three species, Candida incommunis, cryptococcus aerius and Hansenula ciferrii which showed good biomass yield were selected. These three species assimilated methanol as carbon and energy source without mixture of vitamin and yeast extract. The species grown on methanol media were confirmed to have all essential amino acids in their cellular constituents. The content of total amino acids are as followings ; Candida incommunis : 42.5%, Hansenula ciferrii : 39.9%. Of the essential amino acids lysine and threonine which are usually lacking in grain protein were as much as flour's. The experiments on the growth conditions for the higher biomass yield showed the result that the optimum concentration of methanol ans temeprature wre defined as 1.3% and $30^{\circ}C$ in each species.

• International Journal of Highway Engineering
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• v.12 no.3
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• pp.71-77
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• 2010

Anti-freezing layer does not used in case of non frost heaving in subgrade soils. In this case, the modulus of subgrade soils were varied with freezing and thaw cycles under non frost heaving. That effect should be properly considered in pavement design. Impact resonance test that is nondestructive testing method was used for continuously determining the modulus of subgrade soils during freezing and thaw cycle. The modulus of subgrade soils was identical with freezing and thaw cycles under closed freezing and thaw system which is no water supplement into specimen during testing. There was also no difference in the modulus of subgrade soil between before and after freezing-thaw cycles for all specimens with different water content and density. That is thaw-weakening of subgrade soils do not occur under closed freezing and thaw system. The moduli at freezing conditions are varied with water content and density, but it can be ignored in practical design sense.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.12
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• pp.1720-1725
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• 2011

Aspartic acid chelated iron (Asp-Fe) was synthesized by a new method using calcium carbonate, aspartic acid, and ferrous sulfate. This study was carried out to investigate the bioavailability of Asp-Fe in iron-deficient rats. We divided the rats into four experimental groups. The first was the normal diet control group, or NC. The second was the no treated control group of iron-deficient (ID) rats, or ID+C. The third was the heme-iron (heme-Fe) treated group of ID rats, ID+heme-Fe. And the fourth was the Asp-Fe treated group of ID rats, or ID+Asp-Fe. There were no differences among any of the experimental groups in diet consumption, change of body weight, or the weight of the livers, kidneys, or spleens. After 7 days of feeding, the iron content in the sera of the ID+Asp-Fe group (175.2 ${\mu}g$/dL) and the ID+heme-Fe group (140.8 ${\mu}g$/dL) were significantly higher than that of the ID-C group (96.1 ${\mu}g$/dL). The total iron binding capacity (TIBC) of the ID+Asp-Fe group (735.4 ${\mu}g$/dL) was significantly normalized compared to the ID+C group (841.9 ${\mu}g$/dL) or ID+heme-Fe group (824.6 ${\mu}g$/dL). The hematocrit level of the ID+Asp-Fe group was increased to normal levels, but there was no statistical difference among ID groups. The absorption ratio of heme-Fe was 21.3% and that of Asp-Fe was 50.2%, which indicates a 2.3 times higher ratio in comparison with heme iron. With the above results we found that Asp-Fe seems to be an efficient form of iron to supply iron deficient rats in order to cure them of anemia. Thus, these findings suggest that aspartic acid chelated iron has the potential to serve as a functional food related to iron metabolism.

• Journal of the Korean Geographical Society
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• v.40 no.2 s.107
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• pp.242-251
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• 2005

This study investigates the distribution characteristics of medical services in Korea. For the purpose this paper examines the spatial discordance between the provisions of the medical services and the need for them, and analyzes the spatial distribution patterns of medical service in both inter- and intra-regional levels. Disclosed is a severe regional disparity problem in the provision of medical facilities at both inter-regional and intra-regional levels. In recent years people's interest gets increased more in the social well-being of the community, and the resulting strong request makes it desirable to restructure the healthcare service system. This study has thus attempted to draw out the distribution function of the medical facilities, based on the examination of the real data. A particular attention has been paid to whether there exists any hierarchical structure in their size distribution. Quite remarkably, no appreciable hierarchical structure has been observed in the scale of the medical facilities in Korea, in sharp contrast to of the three-level hierarchical structure assumed in the three-level referral system adopted widely. Remarkably, it is revealed that medical facilities in Korea are described by scale-invariant distribution functions. Instead, scale-invariant power-law behavior has been found in the size distribution, which is expected to be rather generic and applicable to other countries as well.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.4
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• pp.292-301
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• 2001

The objectives of this study were to measure the changes in soil moisture regimes and the distribution patterns of inorganic N derived from the fertigated $^{15}N$-labeled urea, and compare them with the results obtained from broadcast-applied soil under the same drip irrigation domain. In fertigated soil, a $^{15}N$-labeled urea solution of $117mg\;N\;L^{-1}$ was applied by surface drip irrigation for 4 weeks. In broadcast-applied soil, no the other hand, 4 g of $^{15}N$-labeled urea(1.87 g N) mixed thoroughly with 5 kg of soil was placed on the surface of packed soil. Soil water status was controlled by drip irrigation scheduled at soil matric potential of -50 kPa. A calibrated time-domain reflectometry probe was installed in the soil vertically 15 cm apart from a drip emitter to control drip irrigation. About 60% of urea-derived inorganic nitrogen was remained in the top zone between 0 and 10 cm depth of fertigated soil, while, most of the inorganic nitrogen (91%) was accumulated in the top zone of broadcast-applied soil. Of inorganic nitrogen derived from urea, the percentage of $NO_3{^-}$ was much higher for fertigation (99%) than for surface application (62%). The relatively lower recovery of urea-derived inorganic nitrogen of broadcast-applied urea-N (51%) than that of fertigated urea-N (89%) was attributable to enhanced $NH_3$ volatilization.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.4
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• pp.356-362
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• 1984

A field experiment was carried out to investigate the sulfur effects on yield, growth and nutritive qualities of soybean in the different fertilizer application methods. Ammonium sulfate and super-phosphate were applied to the soil with levels of 0, 2, 4, and 6Kg S/10a and potassium sulfate, ammonium sulfate and thiourea were applied by foliar application with 2KgS/10a. The results obtained were as follows; 1. Grain and dry matter yield of soybean were increased by the increase of sulfur application and sulfur application showed positive effect on yield components. 2. Sulfur application increased the sulfur content and decreased N/S ratio in grain of soybean. 3. Protein content was increased by raising sulfur application up to 4Kg S/10a. Sulfur application influenced on amino acid composition of soybean protein. Cysteine and methionine contents were increased by sulfur application. 4. Lipid content of soybean grain and inorganic ion absorption by soybean plant were not influenced significantly by sulfur application. 5. In application effects, there was no significant difference among sulfur fertilizers, but foliar application was more effective than soil application.

• Microbiology and Biotechnology Letters
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• v.29 no.4
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• pp.206-211
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• 2001

In order to overexpress constitutively the Kluyveromyces marxianus exoinulinase gene (INUI) in Saccharomyces cerevisiae, four episomal expression systems employing GAPDH, ADHI, PGK and ENOI promoters were constructed as p YIGP aADHI -INU, pPGK-INU, and pENOI- INU plasmids respectively, When S cereviais transformants harboring each plasmid were batchwisely cultivated in the fermentor containing 5% glucose medium no significant differences in the cell growth are observed How- ever the experession level of exoinulinase and plasmid stability showed a strong dependency on the promoter employed. The expression levels of exoinulinase were about 1.70 unit/ml for GAPDH promoter 1.67 unit/ml for PGK promoter, 1.29 unit /ml for ADH1 promoter, and 0.80 unit/ml for ENOl promoter. The plasmid stabilites were maintaines above 80% in all experession systems. except the GAPDH promoter system of 55%, Based on the plas- mid stability and expression level of exoinulinase the ADHl and PGK promoter system were selected for the fed - batch culture to overproduce exoinulinase By the intermittent feeding of yeast extract and glucose, both promoter systems gave the cell concentration of about 30 g-dry cell weight/1 byt the maximal exoinulinase activity of 3.70 unit/ml and plasmid stability of 96% in the ADH1 promoter were higher than those (2.70 unit/ml, 80%) of PGK sys- tem Taking into account the plasmid stability and extended culture time the ADH1 promoter systems would be the most feasible expression systems for the constitutive overproduction of exoinulinase through high cell-density fed- batch cultures using non-selective rich medium.

• Korean Journal of Environmental Agriculture
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• v.30 no.3
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• pp.316-322
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• 2011

BACKGROUND: Pesticides concentration was monitored in 50 agricultural lakes, and ecological risk for aquatic organism was assessed using risk quotient (RQ) and probabilistic methods. METHODS AND RESULTS: Pesticides concentrations detected in 50 agricultural lakes during peak season (June and September) were in the range of $0.17{\sim}0.99{\mu}g/L$. The RQ for algae and the other species was estimated to be 0.25 and below 0.01, indicating medium risk and no risk. Oxadiazon predominantly contributed to RQ value of 99% for algae, fishes, and amphibians. In terms of hazardous concentration at 5% of species ($HC_5$), ecological risk quotients (ERQ) for oxadiazon ranged from 0.18~0.33, showing a medium risk level. Overall, the concentrations of pesticides were much lower than $HC_5$), value. Probability of combined ecological risk for pesticides ranged from 1.82% to 2.41%. CONCLUSION(s): Combined ecological risk probability did not exceed the acceptable level of 5%, indicating no ecological risk for selected aquatic species. This study suggests that regular ecological risk assessment (ERA) will be required to protect and manage an agricultural lake. Not only ERA at screening level by comparing exposure with toxic effects for aquatic species also advanced ERA technique considering species in indigenous to Korea, chronic toxicity, pulse dose, fate, and environmental factors should be required.

• Korean journal of applied entomology
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• v.47 no.3
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• pp.237-248
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• 2008

Development of T. urticae was studied on the leaves of eggplant grown in hydroponics with nitrogen contents of 5 mM, 10 mM, 30 mM, and 60 mM. As the nitrogen level in hydroponics increased, it also increased in the plant whereas that of K, Ca, and Mg decreased. More nitrogen in hydroponics resulted in increased contents of water and crude protein, and decreased ash, carbohydrates, and fibers within the plant. Biomass was the heaviest as 989.5 g at 10 mM and the lightest at 60 mM. Leaf thickness and the content of chlorophyll increased as the content of nitrogen increased. Laboratory leaf disc tests obtained from plants grown at various nitrogen levels revealed that feeding and oviposition preferences of T. urticae were high at 30 mM and low at 5 mM. Ratio of damaged leaf by naturally occurring T. urticae on eggplants of 99 days post-transplant in the greenhouse was the highest as 98% at 60 mM. Degrees of damage on eggplants with and without T. urticae infestation turned up more as the differences in the levels of nitrogen in the hydroponics get bigger. No definite differences in the rate of T. urticae development was found between nitrogen treatment levels but, mortalities in immature stages dropped as the nitrogen levels went up. Adult longevity was the longest of 11.9 for female and 6.9 days for male at 60 mM. Oviposition period was also the longest as 11.7 days at 60 mM and shortened as the level of nitrogen decreased. The number of eggs oviposited was the most as 144.4 at 60 mM while it was the least as 41.0 at 5 mM. Sex ratio was 0.75 in favor of female at 10 mM. $R_o$ and T increased, no trends were detected in $r_m\;and\;{\lambda}$, while Dt decreased as the levels of nitrogen went up.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.4
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• pp.458-465
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• 2010

To investigate the growth and nutrient uptake response of sorghum${\times}$sudangrass ($S{\times}S$) hybrid to different rate of livestock manure compost, a field experiment was conducted in the experimental grassland of Chonnam National University. Six treatments were laid out in a randomized block design with triplicates; control (no input), synthetic fertilizer (20 g N $m^{-2}$ and 20 g $P_2O_5\;m^{-2}$), compost 1 (3.4 g N $m^{-2}$ and 3.6 g $P_2O_5\;m^{-2}$), compost 2 (6.8 g N $m^{-2}$ and 7.2 g $P_2O_5\;m^{-2}$), compost 4 (13.4 g N $m^{-2}$ and 14.4 g $P_2O_5\;m^{-2}$), and compost 6 (20.2 g N $m^{-2}$ and 21.6 g $P_2O_5\;m^{-2}$). Ninety days after treatment, above-ground parts of the plants were harvested and measured for dry matter yield (DMY) and amounts of nutrients (N and P) uptake. Synthetic fertilizer application achieved the greatest DMY (2.4 kg $m^{-2}$) and nutrient uptake (38.3 g N $m^{-2}$ and 15.3 g $P_2O_5\;m^{-2}$). Increasing compost application rate tended to enhance DMY accumulation and nutrient uptake (P<0.01), but DMYs of compost 4 (1.9 kg $m^{-2}$) and 6 (1.8 kg $m^{-2}$) treatments were not different. Therefore, it was suggested that application compost alone may not achieve DMY of $S{\times}S$ hybrid compatible to synthetic fertilizer application. As nutrient uptake efficiency data showed that availability of compost P could be better than SF, it might be a strategy to apply compost as P source with supplementary N application such as liquid manure, SF or green manure if necessary considering availability of N input and the yield goals.