• Journal of Korean Society on Water Environment
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• v.31 no.5
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• pp.460-467
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• 2015

We analyzed the formation of phytoplankton community and the occurences of odorus compound from benthic cyanobacteria in North, South Han-River, Paldang-Lake and Kyeongan-Stream sediments. Sediments were incubated in different water temperature. Akinetes were found (0~500 cells/g) with the highest number on sediment in Yangsoo railroad bridge (YC). The result showed that Anabaena ranged between $0.02{\sim}0.53{\times}10^3cells/mL$ in Sambong (SB), YC, Mukhyen-Stream (MS), Paldang-Lake (P2) and Kyeongan-Stream (KK). The total 68 taxa of phytoplankton were observed during the incubation period. A standing crop of phytoplankton was in the range of $0.13{\sim}8.97{\times}10^3cells/mL$ and Microcystis appeared in SB, YC, P2 and KK sites with $20{\sim}25^{\circ}C$ temperature. In South Han-River (P3), Oscillatoria tenuis was dominant at $25^{\circ}C$ temperature. The concentration of geosmin was the highest in SB-$15^{\circ}C$ (25.5 ng/L), and the concentration of 2-MIB was the highest in P3-$25^{\circ}C$ (286.8 ng/L). Odorous compounds were detected in all the temperature conditions from each site. Our results indicate that the dominant benthic cyanobacteria (O. tenuis, O. limosa, Phormidium tenue and Pseudanabaena limnetica) have high correlation with the occurrence odorous compounds and 2-MIB.

• Korean Journal of Microbiology
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• v.39 no.3
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• pp.197-200
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• 2003

In order to establish effective in situ PCR on the glass slide using the conventional DNA thermal cycler, several parameters should be considered. These include full accessibility of PCR reagents into the cells, prevention of diffusing PCR products out of the cells, loss of PCR reagents by nonspecific adherence onto the glass slide, dryness of PCR reagents by heat, and heat conductivity from the heat block to the glass slide. Especially, to guarantee the full accessibility of PCR reagents to sample, relatively higher concentration of PCR reagents (particularly 4.5 mM of $Mg^{++}$) was required while 5 to 10 units/50 ${\mu}l$ reaction of Taq enzyme was enough as long as the step of pre-PCR incubation was included. Dryness of sample was prevented by addition of distilled water into the empty slots in the heat block, thereby providing the reproducible temperature-time profile of PCR. Observed temperature was lower than the programmed temperature by 3 to $4^{\circ}C$.

• Korean Journal of Materials Research
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• v.11 no.4
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• pp.278-282
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• 2001

The recombination motion of Partial dislocations on basal slip (0001) 1/3<1120> in sapphire ($\alpha$-Al$_2$$O_3$) single crystals was investigated using the four-point bending test with the prism plane (1120) samples. These bending experiments were carried but in the temperature range from $1200^{\circ}C$ to $1400^{\circ}C$ at various engineering stresses 90MPa, 120MPa, and 150MPa. During these tests it was shown that an incubation time was needed for basal slip to be activated. The activation energy for the incubation time was 5.6-6.0eV in the temperature range from $1200^{\circ}C$ to $1400^{\circ}C$. The incubation time is believed to be related to recombination of climb dissociated partial dislocations via self-climb. In addition, these activation energies are nearly same as those for oxygen self-diffusion in $Al_2$$O_3$ (approximately 6.3 eV). Thus, the recombination of the two partial dislocations would be possibly controlled by oxygen diffusion on the stacking fault between the partials.

• The Journal of the Korean Society for Microbiology
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• v.10 no.1
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• pp.25-32
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• 1975

The majority of Nocardial infections reported in North America areIN. ;asteroides while those in Latin America are N. brasiliensis species. Infection with N. brasiliensis, to our knowledge, has not previously been reported in Korea. The auther isolated one strain of Nocardia brasiliensis from the abscess of right bottock of 23 month old female leukemic patient who was treated with methotrixate for five months at the Seoul National University Hospital. The morphological characteristics and biological properties were similar with the R.E. Gordon's description. The results are summarized as follow: 1. After 5 days incubation on Sabouroud's glucose agar, the acid fast character appeared partially. 2. Tyrosine, casein and urea were decomposed by 7 days incubation both at room temperature and at $37^{\circ}C$. 3. Sod, citrate and sod. acetate were utilized at $22^{\circ}C\;and\;37^{\circ}C$ after 28 days incubation while the sod. benzoate utilization was negative. 4. The survival range of temperature was from $10^{\circ}C\;to\;40^{\circ}C$. 5. Dulcitol, galactose, glycerol, lactose, maltose, mannitol, raffinose, rhamnose, sorbitol, trehalose and xylose fermentations were not observed up to 28 days, while the fermentation of glucose and inositol were positive.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.7
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• pp.573-578
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• 2003

Low temperature selective epitaxial growth of Si and SiGe has been obtained using an industrial single wafer chemical vapor deposition module operating at reduced pressure. Epitaxial Si and heteroepitaxial SiGe deposition with Ge content about 20 % has been studied as extrinsic base for self-aligned heterojunction bipolar transistors(HBTs), which helps to reduce the parasitic resistance to obtain higher maximum oscillation frequencies(f$\_$max/). The dependence of Si and SiGe deposition rates on exposed windows and their evolution with the addition of HCl to the gas mixture are investigated. SiH$_2$Cl$_2$ was used as the source of Si SEG(Selective Epitaxial Growth) and GeH$_4$ was added to grow SiGe SEG. The addition of HCl into the gas mixture allows increasing an incubation time even low growth temperature of 675∼725$^{\circ}C$. In addition, the selectivity is enhanced for the SiGe alloy and it was proposed that the incubation time for the polycrystalline deposit on the oxide is increased probably due to GeO formation. On the other hand, when only SiGe SEG(Selective Epitaxial Growth) layer is used for extrinsic base, it shows a higher sheet resistance with Ti-silicide because of Ge segregation to the interface, but in case of Si or Si/SiGe SEG layer, the sheet resistance is decreased up to 70 %.

• Archives of Pharmacal Research
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• v.27 no.1
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• pp.61-67
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• 2004

When ginseng water extract was incubated at $60^{\circ}C$ in acidic conditions, its protopanaxadiol ginsenosides were transformed to ginsenoside $Rg_3$ and ${\Delta}^{20}$-ginsenoside $Rg_3$. However, protopanaxadiol glycoside ginsenosides $Rb_1, Rb_2$ and Rc isolated from ginseng were mostly not transformed to ginsenoside $Rg_3$ by the incubation in neutral condition. The transformation of these ginsenosides to ginsenoside $Rg_3$ and ${\Delta}^{20}$-ginsenoside $Rg_3$ was increased by increasing incubation temperature and time in acidic condition: the optimal incubation time and temperature for this transformation was 5 h and $60^{\circ}C$ resepectively. The transformed ginsenoside $Rg_3$ and ${\Delta}^{20}$-ginsenoside $Rg_3$ were metabolized to ginsenoside $Rh_2$ and $\Delta^{20}$--ginsenoside $Rh_2$, respectively, by human fecal microflora. Among the bacteria isolated from human fecal microflora, Bacteroides sp., and Bifidobacterium sp. and Fusobacterium sp. potently transformed ginsenoside $Rg_3$ to ginsenoside $Rh_2$. Acid-treated ginseng (AG) extract, fermented AG extract, ginsenoside $Rh_2$ and protopanaxadiol showed potent cytotoxicity against tumor cell lines. AG extract, fermented AG extract and protopanaxadiol potently inhibited the growth of Helicobacter pylori.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.6
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• pp.751-760
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• 2015

Management of renewable organic resources is important in attaining the sustainability of agricultural production. However, nutrient management with organic resources is more complex than fertilization with chemical fertilizer because the composition of the organic input or the environmental condition will influence organic matter decomposition and nutrient release. One of the most effective methods for estimating nutrient release from organic amendment is the use of N mineralization models. The present study aimed at parameterizing N mineralization models for a number of organic amendments being used as a nutrient source for crop production. Laboratory incubation experiment was conducted in aerobic condition. N mineralization was investigated for nineteen organic amendments in sandy soil and clay soil at $20^{\circ}C$, $25^{\circ}C$, and $30^{\circ}C$. N mineralization was facilitated at higher temperature condition. Negative correlation was observed between mineralized N and C:N ratio of organic amendments. N mineralization process was slower in clay soil than in sandy soil and this was mainly due to the delayed nitrification. The single and the double exponential models were used to estimate N mineralization of the organic amendments. N mineralization potential $N_p$ and mineralization rate k were estimated in different temperature and soil conditions. Estimated $N_p$ ranged from 28.8 to 228.1 and k from 0.0066 to 0.6932. The double exponential model showed better prediction of N mineralization compared with the single exponential model, particularly for organic amendments with high C:N ratio. It is expected that the model parameters estimated based on the incubation experiment could be used to design nutrient management planning in environment-friendly agriculture.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.6
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• pp.648-657
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• 2015

Soil organic matter (SOM) plays an important role in the continuous production and environmental conservation in arable soils. In particular, the decomposition of organic matter in soil might promote soil organic matter and fertility due to the mineralization of N. In this study, to evaluate the effect of organic matter amendment on the C mineralization and N dynamic, $CO_2-C$ flux, extractable N and $N_2O$ emission were determined using closed chamber for 4 weeks at 10, 15, $20^{\circ}C$ of incubation temperature after the mixture of $2Mgha^{-1}$ rice straw compost and rye in sandy loam and clay loam. Regardless of soil texture, decomposition rates of rice straw compost and rye at $10{\sim}20^{\circ}C$ of incubation temperature ranged from 0.9 to 3.8% and 8.8 to 20.3%, respectively. Rye application in soil increased $NH_4-N$ and $NO_3-N$ content as well as the $N_2O$ emission compared to the rice straw compost. After incubation for 4 weeks, total C content in two soils was higher in rice straw compost than in rye application. In conclusion, application of rice straw compost and rye to soil was able to improve the soil organic matter and fertility. However, organic matter including the recalcitrant compounds like rice straw compost would be effective on the management of soil organic matter and the reduction of greenhouse gases in soil.

• Journal of Ginseng Research
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• v.22 no.4
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• pp.304-309
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• 1998

Incubation condition affecting the chlamydospore formation and isolation from mycelia and conidia of Cylindrocarpon destructanse (isolate ACY-9701), isolated from the root rot lesion of the American ginseng (Panax quinquefolium) was investigated. Chlamydospores were formed from mycilia but not from conidia on the Czapek-Dox agar without carbon or nitrogen source after 20 days incubation at 2$0^{\circ}C$. In the medium added with nitrogen and carbon sources, immatured chlamy-dospore-like cells were formed from microconidia and mycelia as well. Immatured chlamydospore-like cells were formed from mycelia as well as microconidia In corn, kidney bean, and pea root extracts after 20 days incubation at 20"C, while typical chlamydospores were formed from both of them in the root extract of Panax quinquefolium. The 3.6 log chlamydospore/mm" was converted from microconidia in the medium, which was equal to 2.5% conidia formed. Under the light condition (251.1 pmol/m" sec, 12 hrs dark and light cycle), 4.2 log/mm" of chlamydospores were converted from interracially or terminal cells of macroconidia, which was 4.0% of macroconidia produced on Potato dextrose agar (PDA). When mycelia and microconidia were stored at -7$0^{\circ}C$ for 32 days and incubated on PDA after thawing at room temperature to isolate chlamydospores from them, microconidia and mycelia were still alive. Meanwhile, microconidial lysis was found after heating them at 32$^{\circ}C$ for 7 days, but the chlamydospores converted from macroconidia were not lysed up to 13 days at 32"C. to 13 days at 32"C.ot;C.

• Development and Reproduction
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• v.19 no.1
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• pp.25-31
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• 2015

We have launched an investigation for Embryonic Development, Larvae and Juvenile Morphology, of Buenos aires tetra in order to build basic data of Characidae and fish seeding production. We brought 50 couples of Characidae from Bizidduck aquarium in Yeosu-si, Jeollanamdo, from Korea on March of 2015. We put them in the tetragonal glass aquarium ($50{\times}50{\times}30cm$). Breeding water temperature was $27.5{\sim}28.5^{\circ}C$ (mean $28.0{\pm}0.05^{\circ}C$) and being maintained. The shape of fertilized egg was round shape, and it was adhesive demersal egg. The egg size was 0.63~0.91 mm (mean $0.74{\pm}0.07mm$, n=20). After getting fertilized egg, the developmental stage was gastrula stage, and embryo covered almost two-thirds of Yolk. Incubation was happened after 16 hours 13 minutes from gastrula stage, and the tail of juvenile came out first with tearing egg capsule. Immediately after the incubation, prelarvae had 3.78~3.88 mm length (mean $3.84{\pm}0.04mm$, n=5), and it had no mouth and anus yet. 34 days after hatching from the incubation, juvenile had 8.63~13.1 mm (mean $10.9{\pm}1.66mm$), and it had similar silver-colored body shape with its mother.