• Korean Journal of Remote Sensing
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• v.37 no.6_2
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• pp.1859-1867
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• 2021

This study investigated seasonal characteristics of the particulate matter (PM) in the atmosphere and rainwater quality in Busan, South Korea, and evaluated the seasonal effect of PM₁₀ concentration in the atmosphere on the rainwater quality using multivariate statistical analysis. The concentration of PM in the atmosphere and meteorological observations(daily precipitation amount and rainfall intensity) are obtained from automatic weather systems (AWS) by the Korea Meteorological Administration (KMA) from March 2020 to August 2020. Rainwater samples (n = 216, 13 rain events) were continuously collected from the beginning of the precipitation using the rainwater collecting device at Pukyong National University. The samples were analyzed for pH, EC (electrical conductivity), water-soluble cations(Na⁺, Mg²⁺, K⁺, Ca²⁺, and NH₄⁺), and anions(Cl^-, NO₃^-, and SO₄^2-). The concentration of PM₁₀ in the atmosphere was steadily measured before and after the precipitation with a custom-built PM sensor node. The measured data were analyzed using principal component analysis (PCA) and Pearson correlation analysis to identify relationships between the concentration of PM₁₀ in the atmosphere and rainwater quality. In spring, the daily average concentration of PM₁₀ (34.11 ㎍/m³) and PM_2.5 (19.23 ㎍/m³) in the atmosphere were relatively high, while the value of daily precipitation amount and rainfall intensity were relatively low. In addition, the concentration of PM₁₀ in the atmosphere showed a significant positive correlation with the concentration of water-soluble ions (r = 0.99) and EC (r = 0.95) and a negative correlation with the pH (r = -0.84) of rainwater samples. In summer, the daily average concentration of PM₁₀ (27.79 ㎍/m³) and PM_2.5 (17.41 ㎍/m³) in the atmosphere were relatively low, and the maximum rainfall intensity was 81.6 mm/h, recording a large amount of rain for a long time. The results indicated that there was no statistically significant correlation between the concentration of PM₁₀ in the atmosphere and rainwater quality in summer.

• Applied Chemistry for Engineering
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• v.33 no.6
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• pp.588-593
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• 2022

The effects of P₂O₅-doped on the surface of MgO particles on hydrolysis, water repellency, and insulation behavior were investigated. P₂O₅-doped MgO has exhibited a unique electrical property, which is significant insulation behavior due to both the suppression of the hydrolysis reaction by P₂O₅ and water repellency. Therefore, the insulation behavior was inversely proportional to the hydrophilicity and the Mg(OH)₂ and OH^-charge transfer ratio by the surface hydration reaction of MgO. The insulation of MgO according to aging was strongly influenced by the surface hydration reaction, the band gap of the added dopant species, and the hydrophilicity and hydrophobicity of the dopant. Finally, it was to show electrical insulation by inhibiting the surface hydration reaction of the hydrophilic MgO, which has a great potential for use in heat transfer medium applications.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.5
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• pp.645-654
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• 2022

This study was conducted to prepare superheated steam roasted (SSR) small yellow croaker Larimichthys polyactis sweet potato salad (SPS) and tomato mousse (TM), as senior-friendly seafoods (SFS) and to examine their quality characteristics. The hardness values of SSR, SPS and TM were 110.5×1.0³, 22.4×1.0³ and 14.5×1.0³ N/m², respectively. The nutritional properties of SSR, SPS and TM were 22.4, 6.7 and 10.2 g/100 g, respectively, for protein, 97.01, 3.40 and 17.00 ㎍/100 g, respectively, for vitamin A, 10.26, 2.79 ㎍/100 g and not detected (ND), respectively, for vitamin D, 60.68 mg/100 g, ND and 4.17 mg/100 g, respectively, for vitamin C, 0.18, 0.10 and 0.33 mg/100 g, respectively, for riboflavin 24.28, 10.91 and 13.77 mg/100 g, respectively, for niacin, 76.3, 53.0 and 48.5 mg/100 g, respectively, for calcium, 258.2, 231.3 and 145.2 mg/100 g, respectively, for potassium, and ND, 0.70 mg/100 g and ND, respectively, for dietary fiber. Escherichia coli was not detected in any of the products. These results suggested that the products should be classified as step 1 for SSR, step 2 for SPS and step 3 for TM based on the SFS standard of the Korean industrial standards. Moreover, the nutritional and physical properties of the foods were improved.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.34 no.1
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• pp.85-97
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• 2024

Objectives: This study was intended to investigate the revision status of the occupational exposure standards for aluminum at home and abroad; to investigate worker exposure at domestic aluminum manufacturing and handling workplaces; to conduct social and economic evaluation for the revision of domestic aluminum exposure limits. Methods: We investigated the current status of occupational exposure limits for aluminum at home and abroad, and analyzed supporting data. An exposure survey was conducted targeting domestic aluminum manufacturing and handling workplaces. Based on these, revised aluminum occupational exposure limits were proposed. Results: The major aluminum exposure limits at home and abroad show a notable difference. The toxicity of aluminum, which was revealed through animal experiments and epidemiological investigations. The average concentration of aluminum in the air at 12 workplaces was 0.016 mg/m³, and the maximum was 0.0776 mg/m³. When total dust and respiratory dust were measured side by side and simultaneously for the same process, 12.1% of the total mass concentration of aluminum dust was respiratory dust. As a result of measuring and comparing the size distribution of dust with an optical particle counter in real time, 48.1% of the total dust in the form of welding fume and pyro-powder was respiratory dust. Based on the literature review and workplace survey, three proposals for changing the aluminum exposure limit were proposed. Proposal (1): For all types, 10 mg/m³ is unified as the exposure limit except for soluble salts and alkyls. Proposal (2): 1(R) mg/m³ as the exposure limit for all forms except soluble salts and alkyl. Proposal (3): 1(R) mg/m³ for pyro-powder and welding fume, and 10 mg/m³ for metal dust, aluminum oxide, and insoluble compounds as exposure standards. A pyro-powder was defined as dry aluminum powder of 200 mesh size (74 ㎛) or smaller (larger size classified as metal dust). Reason for setting: In the workplace survey, the ratio of respiratory dust to total dust was analyzed to be about 1:10, so it was judged that the domestic standard and the ACGIH standard were compatible. Conclusions: In all scenarios according to the revision of the exposure standard, the B/C ratio was greater than 1 or only benefits existed, so it was evaluated as sufficiently reasonable as a result of the socio-economic evaluation.

• Journal of Pharmaceutical Investigation
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• v.38 no.1
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• pp.73-78
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• 2008

To evaluate the bioequivalence of two ramipril formulations, a standard 2-way randomized cross-over study was conducted in twenty-six healthy male Korean volunteers. A single oral dose of 10 mg of test formulation $Ramiprin^{(R)}$ (tablet) or reference formulation Tritace $Protect^{(R)}$ (tablet) was administered with one-week washout period. Plasma concentrations of ramipril were assayed over a period of 12 hr with a well validated method using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The values of area under the plasma concentration-time curve, from time zero to last sampling time $(AUC_t)$ and from time zero to time infinity $(AUC_{inf})$ were $77.45{\pm}44.78\;and\;78.96{\pm}45.64$ for test, and $70.30{\pm}42.27\;and\;71.99{\pm}43.55ng\;hr/mL$ for reference formulation, respectively. Similarly, maximum concentration $(C_{max})$ and elimination half-life $(t_{1/2})$ were $65.61{\pm}19.96ng/mL$ and $2.15{\pm}0.75hr$ for test, and $63.63{\pm}25.50ng/mL$ and $2.16{\pm}0.73hr$ for reference formulations, respectively. Time to reach maximum concentration $(T_{max})$ for the test and the reference, were $0.51{\pm}0.22hr\;and\;0.52{\pm}0.18hr$, respectively. The parametric 90% confidence intervals on the mean of the differences between the two formulations (test-reference) of the log-transformed values of $AUC_t\;and\;C_{max}$ were 1.03 to 1.19 and 0.98 to 1.17, respectively. The overall results indicate that the two formulations are bioequivalent and can be prescribed interchangeably.

• Journal of Korean Society of Forest Science
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• v.109 no.2
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• pp.169-178
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• 2020

This study aimed to compare the organic carbon stocks of Cryptomeria japonica and Chamaecyparis obtusa stands established under a similar-site environmental condition in South Korea. C. japonica and C. obtusa stands adjacent to each other from 13 representative regions were chosen to evaluate the carbon stocks of tree biomass, forest floor, and mineral soils. Mean stand ages were 45 years for C. japonica and 43 years for C. obtusa, respectively. Tree density was significantly lower in C. japonica (989 tree ha^-1) than in C. obtusa (1,223 tree ha^-1) stands, whereas diameter at breast height and dominant tree height values were significantly higher in C. japonica (27.4 cm and 20.4 m, respectively), compared with C. obtusa (23.9 cm and 17.9 m, respectively) stands. The total carbon stocks of tree biomass were linearly related with stand basal area (C. japonica: r² = 0.82; C. obtusa: r²= 0.92; P< 0.05), whereas stand density and site index were not correlated with the carbon stocks of tree biomass (P > 0.05). The carbon stocks of aboveground tree biomass were significantly higher in C. obtusa (117.7 Mg C ha^-1), compared with C. japonica (95.5 Mg C ha^-1) stands, whereas carbon concentration and stocks of the forest floor and mineral soil layers were insignificantly different between the C. japonica and C. obtusa stands. The results indicated that trees in C. obtusa stands sequestrated more carbon dioxide, compared with C. japonica stands, whereas carbon stocks in the forest floor and mineral soil layers were unaffected by stand development processes of the different tree species.

• Microbiology and Biotechnology Letters
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• v.43 no.2
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• pp.164-168
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• 2015

Citric acid is produced via submerged fermentation using yeasts. Among eight different strains of yeast, Candida zeylanoides was chosen as the strain for producing citric acid and optimized for various C/N ratios and effects of phosphate or Fe²⁺ ions in a clean carbon source medium (glucose: fructose, 1:1). The yield of citric acid was maximized at a C/N ratio of 40/1, a phosphate addition of 1.0 g/l, and an Fe²⁺ ion concentration of less than 50 mg/l, yielding up to 91 g/L in the broth with 18.5 g/l of isocitric acid in a six-day fermentation period using a pre-treated molasses medium. The yield of batch culture was 0.51 (Y_p/s, g/g) in a 5 L-Jar fermenter.

• Korean Journal of Clinical Laboratory Science
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• v.54 no.4
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• pp.273-278
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• 2022

This study evaluates the improved effect of photodynamic therapy (PDT) by subjecting pathogenic bacteria to a combination of 630 nm light-emitting diode (LED) and 5-aminolevulinic acid (ALA). Bacterial suspensions of 1.5×10⁴ cells/mL were diluted and exposed to ALA concentrations of 10, 5, 2.5, 1.25, and 0.625 mg/mL, incubated for 30 minutes, followed by irradiation with 630 nm LED (18 J/cm² ). The non-irradiated P. aeruginosa group and the group administered only LED light averaged 415 and 245 colonies, respectively. Conversely, the PDT group showed an average of 109, 225, 297, and 285 colonies at concentrations of 10, 5, 2.5, and 1.25 mg/mL of ALA. Evaluating the effect on E. faecalis revealed an average of 8,750 and 8,000 colonies in the group that did not receive the control photosensitizer and the group exposed to light alone, respectively. However, an average of 0, 2350, 4825, and 7475 colonies at concentrations of 5, 2.5, 1.25, and 0.625 mg/mL ALA were determined for the PDT groups. In conclusion, better inhibitory effects were observed for E. faecalis than for P. aeruginosa. Moreover, our results validate the possibility of improved PDT efficacy using a combination of ALA and 630 nm LED.

• Journal of Bio-Environment Control
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• v.29 no.1
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• pp.80-88
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• 2020

This study was conducted to examine the effect by application method and concentration of the indole-3-butyric acid (IBA), which is auxin-based plant growth regulator, on the growth and runner plants production of strawberry in the greenhouse. The seedlings of strawberry were transplanted in the pot (150 ×135 × 90 mm) filled with coir medium on April 12, 2019. The IBA was applied with a foliar spray or drench as 50, 100, 150, and 200 mg·L^-1 (50 mL per plant), respectively. The treatment was started on April 29, 2019. The foliar spray and drench treatment of IBA were repeated at 2-week intervals for 9 weeks from the start date of treatment. At 9 weeks after treatment, the petiole length of mother plants was the shortest in the control. The number of runner plants showed a tendency to decreased in the foliar spray. The number of lateral buds showed a tendency to decreased in the IBA treatment, and the least in the foliar with 100 mg·L^-1. There was not significantly difference in the fresh and dry weights of the first and second runner plants. However, in the third runner plants, the fresh and dry weights were the greatest in the drench with 100 mg·L^-1. Therefore, when considering the growth of third runner plants and lateral bud suppression, the drench with the 100 mg·L^-1 could be better application method and concentration of IBA treatment for growth of the third runner plants and runner plants production of strawberry, and the results can be used as a basic research of plant growth regulator application to save the labor force and enhance the seedling quality in strawberry seedling stage.

• Journal of Forest and Environmental Science
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• v.36 no.1
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• pp.37-46
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• 2020

Vegetation carbon sequestration and regeneration are the two major parameters of forest research. In this study, we analyzed the vegetation carbon stock and regeneration of community-managed pine plantation of Kathmandu, central Nepal. Vegetation data were collected from 40 circular plots of 10 m radius (for the tree) and 1m radius (for seedling) applying a stratified random sampling and nested quadrat method. The carbon stock was estimated by Chave allometric model and estimated carbon stock was converted into CO₂ equivalents. Density-diameter (d-d) curve was also prepared to check the regeneration status and stability of the plantation. A d-d curve indicates the good regeneration status of the forest with a stable population in each size class. Diversity of trees was very low, only two tree species Pinus roxburghii and Eucalyptus citriodora occurred in the sample plots. Pine was the dominant tree in terms of density, basal area, biomass, carbon stock and CO₂ stock than the eucalyptus. The basal area, carbon stock and CO₂ stock of forest was 33±1.0 ㎡ ha^-1, 108±5.0 Mg ha^-1 and 394±18 Mg ha^-1, respectively. Seedling and tree density of the plantation was 4,965 ha^-1 and 339 ha^-1 respectively. The forest carbon stock showed a positive relationship with biomass, tree diameter, height and basal area but no relationship with tree density. Canopy cover and tree diameter have a negative effect on seedling density and regeneration. In conclusion, the community forest has a stable population in each size class, sequestering a significant amount of carbon and CO₂ emitted from densely populated Kathmandu metro city as the forest biomass hence have a potentiality to mitigate the global climate change.