• Journal of Microbiology and Biotechnology
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• v.30 no.5
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• pp.717-725
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• 2020

The use of plant growth-promoting rhizobacteria is economically viable and environmentally safe for mitigating various plant stresses. Abiotic stresses such as flood and drought are a serious threat to modern agriculture. In the present study, the indole-3-acetic acid-producing rhizobacterium R. sphaeroides KE149 was selected, and its effects on the growth of adzuki bean plants under flood stress (FS) and drought stress (DS) were investigated. IAA quantification of bacterial pure culture revealed that KE149 produced a significant amount of IAA. Moreover, KE149 inoculation notably decreased stress-responsive endogenous abscisic acid and jasmonic acid and increased salicylic acid in plants under DS and FS. KE149 inoculation also increased proline under DS and methionine under FS. In addition, KE149 inoculation significantly increased the levels of calcium (Ca), magnesium (Mg), and potassium (K) while lowering the sodium (Na) content in the plant shoot under stress. KE149-treated plants had markedly greater root length, shoot length, stem diameter, biomass, and higher chlorophyll content under both normal and stressed conditions. These results suggest that KE149 could be an efficient biofertilizer for mitigating water stress.

• Journal of Korean Society for Atmospheric Environment
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• v.18 no.E4
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• pp.203-213
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• 2002

Receptor modeling is one of statistical methods to achieve reasonable air pollution strategies. In order to maintain and manage ambient air quality, it is necessary to identify sources and to apportion its sources for ambient particulate matters. The main purpose of the study was to survey seasonal trends of inorganic elements in the coarse and fine particles. Second, this study has attempted emission sources qualitatively by a receptor method, the PMF mo-del. After that. both PMF (positive matrix factorization) model and TTFA (target transformation factor analysis) model were applied to compare and to estimate mass contribution of coarse and fine particle sources at the receptor. A total of 138 sets of samples was collected from 1989 to 1996 by a low volume cascade impactor with 9 size fraction stages at Kyung Hee University in Korea. Sixteen chemical species (Si, Ca, Fe, K, Pb, Na, Zn, Mg, Ba, Ni, V, Mn, Cr, Br, Cu. Co) were characterized by XRF. The study result showed that the weighted arithmetic mean of coarse and fine particles were 51.3 and 54.4 $\mu\textrm{g}$/㎥, respectively. Contribution of both particle fractions were esti-mated using TTFA and PMF models. The number of estimated sources was seven according to TTFA model and 8 according to PMF model. Comparison of TTFA and PMF revealed that both methodologies exhibited similar trends in their contribution pattern. However, large differences between contributions were observed in some sour-ces. The results of this study may help to suggest control strategies in local countries where known source profiles do not exist.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.4
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• pp.276-280
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• 2013

D. kaki and D. lotus are used as rootstocks for astringent persimmons in Korea but characteristics of their seedlings have not been determined. In this experiment, their seeds were sown in 3-L pots on April 18 and the seedlings were grown until October 24. Growth and nutrient absorption were compared at the end of the season after destructively harvesting the seedlings. Seedling growth of D. lotus was much faster than that of D. kaki in terms of total stem length, stem diameter, and number of leaves. However, chlorophyll value and specific leaf weight were higher in D. kaki than in D. lotus. Dry weight of D. lotus was 3.6- and 3.7-fold higher than that of D. kaki in above-ground parts and the root, respectively. D. kaki seedlings were characterized by higher concentrations of N, P, K, Ca, and Mg in the leaves, stem, or the root. However, total contents of the elements were 1.8- to 3.7-fold higher in a D. lotus seedling due to its greater dry weight. Since D. lotus seedlings absorbed more inorganic elements on a tree basis and grew more vigorously than D. kaki seedlings, the level of fertilization for astringent persimmons should be adjusted depending on rootstocks to maintain the trees at the optimum vigor.

• Korean Journal of Materials Research
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• v.1 no.4
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• pp.206-213
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• 1991

The crystallized solder glasses with the low melting temperature for electronic package were prepared with the compositions of 77-80wt% PbO, 4.5-6wt% ZnO, 7.5-8.5wt% $B_2O_3$, 1-2wt% CaO, and 0.5-2.0wt% $P_2O_5$ containing 3-7wt% $TiO_2$. The Characterization of the solder glasses were studied using DTA, SEM and XRD. Frit containing 3wt% $TiO_2$ had crytallzation temperature range of $420-440^{\circ}C$. The major crystalline phase was identified as $2PbO{\cdot}ZnO{\cdot}B_2O_3$ by X-ray diffraction. Frits containing 4 wt% $TiO_2$ consisted of crysalline Phases of $PbTiO_3$ and $2PbO{\cdot}ZnO{\cdot}B_2O_3$ in the temperature range of $420-440^{\circ}C$, When g1ass frit containing 5wt% $TiO_2$ were heat-treated in the temperature range of $440-460^{\circ}C$, major crytalline phase was perovskite lead titanate.

• Journal of The Korean Society of Grassland and Forage Science
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• v.40 no.1
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• pp.37-43
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• 2020

This study was conducted to evaluate the effects of different nitrogen levels on the yield and nutrient quality of a newly developed domestic hybrid of Teosinte, Geukdong 6〔Zea mays L. subsp. mexicana (Schrad.) H. H. Iltis〕. The field experiment was conducted in a randomized block design with three replicates and consisted of four nitrogen (N) application rates, T1 (200 kg/ha), T2 (300 kg/ha), T3 (400 kg/ha), and T4 (500 kg/ha). No differences were found in plant length, leaf length, leaf width, leaf number, dead leaves, stem hardness, tiller number, and fresh yield (p>0.05). The T3 showed significantly greater dry matter yield at harvest (heading stage) compared to the other treatments (p<0.05). The crude protein content of T4 (10.49%) was higher than those of T1 and T2 (p<0.05). However, there was no significant difference between T4 (10.49%) and T3 (9.63%). The effects on crude fat, crude ash, neutral detergent fiber (NDF), acid detergent fiber (ADF), and crude fiber were not significant (p>0.05). The sugar content was higher in the T2 treatment than the other treatments (p<0.05). For Ca, T3 showed significantly greater content (p<0.05). However, no significant effects were found in the contents of Cu, Fe, K, Mg, Mn, Mo, and Zn (p>0.05). Na content was higher in order of T2 > T4 > T3 > T1 (p<0.05). Total mineral contents were not significantly different among the treatments (p>0.05). Given these results, we recommend the amount of nitrogen fertilization necessary for "Geukdong 6" to be around 400 kg per ha (T3), when considering, high fresh yield, dry matter yield, number of leaves and content of crude protein.

• The Korean Journal of Mycology
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• v.28 no.2
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• pp.81-87
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• 2000

The optimal synthetic medium, temperature and pH range for the mycelial growth of Cordyceps scarabaeicola were PDA, $25^{\circ}C$, and pH $8.0{\sim}8.5$, respectively. The effects of carbon sources, nitrogen sources and mineral salts on mycelial growth were superior to lactose, ammonium phosphate and $CaCl_2$, respectively. Liquid spawn culture was selected out BM(brown sugar 3%, soybean flour 0.3%, potassium phosphate 0.05%, magnesium sulfate 0.05%) medium.

• Journal of the Korean Society of Food Science and Nutrition
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• v.19 no.6
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• pp.596-604
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• 1990

Polygalacturonase activity was not detected at turning stage but were 55.01 and 206.70 units/100g -fr. wt. in mature and soft persimmon, respectively. Polygalacturonase have two isoenzymes and its molecular weight was estimated to be 55,000 doltons by the method of gel filtration. Vmax and Km of polygalacturonase 1 were 0.195$\mu$ mole reducing-sugar/$m\ell$/30 min. and 3.50mg/$m\ell$, respectively. The optimum temperature and pH of the enzyme appeared to 4$0^{\circ}C$ and 3.5, respectively. Polygalacturonase I had Vmax of 0.110m mo1e reducing-sugar/$m\ell$/30min. and Km value of 2.50mg/$m\ell$, The optimum temperature and pH of polygalcturonase II appear 4$0^{\circ}C$ and 4.0, respectively. Polygalacturonase I was fairly stable at 6$0^{\circ}C$while polygalacturonase II appeared to be stable up to 4$0^{\circ}C$.

• Journal of the Korean Chemical Society
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• v.31 no.1
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• pp.14-24
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• 1987

The CNDO/2 method has been used to calculate the electronic structure of the zeolites and silicas, and to investigate the interaction of CO molecules with the OH groups or the exchanged cation in the zeolites. The interaction energies of CO molecules with OH groups in silica were ca. 12kcal/mol, the bond distance, R(O-H${\cdots}$C) was 2.6${\AA}$. The strength of bond between CO molecules and various types of cations in the zeolites was in the following order: $H^+ < Na^+ < Li^+$, i.e., this increased with increasing electrostatic field of cations. The bond orders of CO molecules interacting with the OH groups or the cations increased but for the OH-OC type interaction. The theoretical decationization energies of exchanged cations in the zeolites decreased in the order: $H^+ > Li^+ > Na^+$. And these energies depended on the amount of charge density transfered from the skeleton to the cations in order to compensate its negative charge.

• Research in Community and Public Health Nursing
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• v.26 no.1
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• pp.1-10
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• 2015

Purpose: This study was conducted to investigate changes in cognitive functions, depression and life-satisfaction for elderly participants with mild cognitive impairments participating in an individual cognitive improvement program. Methods: A quasi-experimental with non-equivalent control group pretest-posttest design was implemented. The participants were senior citizens over 65 years of age who had been clinically diagnosed with mild cognitive impairments in G City and J Province (experimental group: 29, control group: 27). The experimental group participated in the individual cognitive improvement program based on Korean traditional tales and games for nine weeks. Results: After the intervention, only the participants in the experimental group reported significant improvement in K-MMSE (t=-2.5, p=.016), MoCA-K (t=-2.6, p=.008), depression (t=3.51, p=.001), and life satisfaction (t=-2.75, p=.008) when compared to those in the control group. Conclusion: These results indicated that the individual cognitive improvement program was effective in improving cognitive functions, depression, and life-satisfaction among the elderly with mild cognitive impairments. Therefore, the application of this individual cognitive improvement program developed in this study by visiting nurses may strengthen the cognitive functions of seniors with mild cognitive impairments.

• The Korean Journal of Ecology
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• v.19 no.3
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• pp.271-282
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• 1996

This study was aimed to observe the effects of municipal sewage sludge as a organic fertilizer on the growth and KDICical omposition of Altari radish (Raphanus sativus). The accumulation rate of heavy metals of the sludge in the radish was also observed. Municipal sewage sludge of Taejon City was applied to the soil of Pai-Chai University Farm to make 6 gradients of sludge contents in the soil. Root weight of Altari radish was affected significantly by N and P contents in the soil. The longest leaves and roots were produced in the control group, in which urea was applied as nitrogen source to the soil. Even though any other sludge-applied groups produced shorter leaves and roots than the control group, the length of the leaves and roots and the weight of the whole plant of the radish tended to increase with the increase of the sludge application. Contents of N, K, Ca and Mg in the radish were not significantly different among those in 6 experimental groups, but P contents in leaves varied among the 6 groups. Zn content of spring Altari radish treated with 200% sludge was 57.6 mg/kg. It is the highest contents among 6 experimental groups. Contents of Zn, Mn and Cd were higher in leaves than in roots, but less than those in market vegetables. From the above results, it is concluded that municipal sewage sludge can be applied as organic fertilizer to the growth of Altari radish. But this sludge could not be applied under our current regulations, which must be reviewed at intra-governmental leavels.