• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.7
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• pp.914-919
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• 2019

A mesocosm experiment considering water exchange was conducted to evaluate the change in the properties of contaminated coastal sediment. The contaminated coastal sediment sample was prepared by mixing with granulated coal ash(GCA), which is an alkaline industrial by-product. During one month of observation time, the phosphate concentration of the GCA sample case was measured to be 19.0 and 0.4 mg/L lower than that of the control sample at the pore water and overlying water, respectively. The hydrogen sulfide concentration of the GCA sample case was 5.0 mg/L, which is significantly lower than that of the control sample(112.5 mg/L). Further addition of GCA in the sediment reduced the concentrations of phosphate and hydrogen sulfide, and could enhance the adsorption reaction, when compared to the sediment without GCA. The dissolved oxygen concentration in the overlying water of the GCA sample was measured to be 3.47 mg/L higher than the control sample. From the above results, we confirmed that GCA is an effective material for reducing pollutants in coastal sediment.

• Polymer(Korea)
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• v.29 no.5
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• pp.440-444
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• 2005

An increase in the surface area of drugs by reducing particle sizes from microns to nanometers has been known as an efficient method to improve the bioavailability of water-insoluble drugs. To prevent drug nanoparticles from aggregation during the processes of drug formulation, a limited number of pharmaceutical inactive ingredients such as hydroxypropyl cellulose has been employed as stabilizers or dispersants. In this study, copolymers of hydrophilic and hydrophobic amino acids were synthesized by the ring opening polymerization of their N-carboxyanhydride monomers and evaluated as novel candidates to stabilize the nanoparticles of a water insoluble drug, naproxen. Naproxen nanoparticles stabilized by synthesized amino acid copolymers were successfully prepared in the size of $200\~500nm$ in 60 min by a wet comminution process. Particle size analysis showed that the effective stabilization performance of copolymers required the hydrophobic moiety content to be higher than $10 mol\%$. However, the molecular weight and morphology of copolymers was not the critical parameters in determining the particle size reduction. Their particle size was found to be stable up to 14 days without significant aggregation.

• Journal of Life Science
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• v.23 no.2
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• pp.249-258
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• 2013

The antioxidative activity and bioactivity of water, ethanol, and methanol extracts from Paecilomyces japonica (PJ), Cordyceps militaris (CM), and cordycepin-enriched C. militaris JLM0636 ($CM{\alpha}$) were tested in in vitro experimental models. The PJ water extract showed the highest extraction yield (42.53%). The highest content of phenolic compounds and flavonoids were found in the water extract of PJ, 2.72% and 1.73%, respectively. The major minerals were K, Mg, and Ca. The water extracts of PJ also showed the highest DPPH free radical scavenging activity and reducing power. Linoleic acid peroxidation and antioxidative activities were strong in $CM{\alpha}$. The methanol extracts of PJ showed the highest inhibition activity against tyrosinase. Fibriolytic activity was higher in $CM{\alpha}$ than in CM. These results may provide basic data to understand the biological activities of bioactive materials derived from $CM{\alpha}$ for the development of functional foods, cosmetics, and antithrombotics.

• Applied Chemistry for Engineering
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• v.27 no.2
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• pp.221-226
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• 2016

Production of eco-friendly and biologically harmless materials is strongly required in all industries. In particular, reducing volatile organic compounds in coating processes is extremely important to secure worker's safety. During recent two decades, extensive research works on water-borne polyurethane dispersion (PUD) have been continuously developed as an alternative to solvent-borne polyurethane. However, PUD was shown inferior mechanical properties to the organic solvent-borne polyurethane due to a limit to the molecular weight increase, which resulted in the limit of applications. To overcome this drawback, several approaches have been examined such as polymer blends and thermal/radiation induced crosslinking. Among these methods, the radiation curing system was suitable for industrialization because of the high crosslinking density and fast curing speed. In this study, we overcame the drawback for PUD via introducing benzophenone radiation curable units to PUD. We synthesized PUD films which possessed good dispersion in water for 30 days, increased Tg and Td more than $5^{\circ}C$ after UV curing film as well as improved young's modulus more than double.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.367-367
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• 2018

전 세계적으로 이상기후에 의한 영향으로 여름철 장마와 같은 우기가 점차 사라지고 집중호우 및 가뭄이 빈번하게 발생하는 등 지하수위 변동성에 따른 물 부족 현상이 발생하고 있다. 특히, 제주특별자치도는 하천수 및 저수지의 수원을 농업용수로 이용하는 내륙지역과는 달리 농업용수의 수원으로 지하수를 이용하고 있어 향후 기후변화로 인한 극단적인 가뭄과 농업형태의 변화등 지하수의 의존도는 가속화 될 전망이다. 따라서, 제주특별자치도는 지하수 관리차원에서 신규관정개발을 최소화 하고 용수공급량의 부족과 불균형을 해소시키기 위하여 2016년부터 농업용수 광역화 사업을 추진하고 있다. 본 연구는 제주특별자치도에서 추진하고 있는 '농업용수 광역화 사업'과 연계하여 용천수를 활용한 농업용 수자원 확보를 위하여 용천수 및 상시하천수의 정량적인 수량파악 및 농업용 수질기준에 적절한 유출수를 선정하고 제주지역 농업용수에 대체수자원을 활용한 지하수 의존비율을 저감시키는데 목표를 두고 수행되었다. 제주특별자치도 서귀포 지역에 분포하고 있는 16개 용천수 및 2개 상시하천을 대상으로 최종 해안으로 유출되는 10개 지점에서 농업용수 활용가능성을 검토한 결과 최소 유량 값은 각 지점별로 속골물 6,313.3($m^3$/일), 조이통물 11,406.3($m^3/day$), 꿩망물 8,402.8($m^3/day$), 선궷내물 4,290.8($m^3/day$), 논짓물 690.8($m^3/day$), 대왕수 1063.0($m^3/day$), 작지물 7,060.4($m^3/day$), 하강물 1,487.6($m^3/day$), 악근천 1,043.6($m^3/day$), 예래천 2,114.4($m^3/day$)로 산정되었으며, 수질 분석에 있어서는 작지물을 제외한 9개 지점에서 농업용수 사용 기준을 충족 하였다. 이상의 결과는 향후 제주특별자치도의 농업용수 공급량의 부족과 불균형 해소 및 지하수 관리차원의 신규관정 개발을 최소화 하는데 보탬이 될 것으로 판단된다.

• Journal of Ecology and Environment
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• v.43 no.3
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• pp.305-313
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• 2019

Background: This research aims to study the effect of climate change on the phenology, growth, and physiological traits of Silene capitata Kom., a Korean endangered species II. This study increased $CO_2$ concentration in a closed glass greenhouse, with the daily mean temperature and $CO_2$ concentration respectively being $4.61^{\circ}C$ and 93.63 ppm higher than the outside temperature (ambient conditions, control). The seeds of S. capitata were sown in control and treatment environments in March 2013 while seedlings were transplanted into individual pots in May 2013. To research phenological changes, the first day of the flowering and ripening of the plants transplanted in 2013 and first day of leafing in 2014 were observed. The growth and physiological responses of mature leaves were also studied in 2013. Results: There was no difference in the first day of flowering, but the first day of ripening was earlier in the treatment group than the control group. There was no difference in the number of rosette leaves between the two groups, but leaf area was wider in the treatment group than the control group. Transpiration rate and stomatal conductance were higher in the treatment group than the control group, chlorophyll content decreased, and photosynthetic rate and water use efficiency were the same for both groups. As a result of simple regression analysis among the transpiration rate, stomatal conductance, photosynthetic rate, and water use efficiency, stomatal conductance increased when transpiration rate increased. Stomatal conductance increased with photosynthetic rate in the control unlike in the treatment group. The photosynthetic rate and water use efficiency increased with transpiration rate in the control group unlike in the treatment group. Furthermore, water use efficiency increased as photosynthetic rate increased in both groups. Conclusion: Due to high $CO_2$ concentration, the photosynthetic rate was no longer controlled by the stomata, which appeared to suppress the excessive production of photosynthetic products by reducing chlorophyll content. It is believed that the phenological responses of S. capitata under climate change conditions will advance and that stable growth will be difficult in regions lacking moisture due to the high transpiration rate.

• The Korean Journal of Food And Nutrition
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• v.33 no.6
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• pp.692-701
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• 2020

Centella asiatica (CA) has been widely used as herbal plants. It is a valuable resources. The aim of the present study was to evaluate physiological activities of solvent extracts from CA cultivated in Chungju, Korea (Good tiger care). After preparing water (cold-water, CA-WE; hot-water, CA-HWE) and EtOH extracts (50% EtOH, CA-50E; 70% EtOH, CA-70E), their total polyphenol, flavonoid, and triterpenoid contents, and anti-oxidant activities, and anti-inflammatory activities were examined and compared. CA-70E showed the most potent anti-oxidant activity based on ABTS radical scavenging activity and reducing ability assays, while CA-50E and CA-70E showed the highest DPPH radical scavenging activity. Among major triterpenoid glycosides present in CA, madecassoside and asiaticoside contents were found to be the highest in CA-70E, and madecassic acid and asiatic acid were the highest in CA-50E. In LPS-stimulated RAW 264.7 cells, CA-70E showed the highest TNF-α inhibitory activity, although CA-50E and CA-70E similarly inhibited nitric oxide production. Ethanol extracts significantly inhibited IL-6 and IL-8 production more than water extracts using TNF-α/IFN-γ-stimulated HaCaT cells, indicating its better inhibitory against skin inflammation. Therefore, Chungju-CA EtOH extract, especially 70% EtOH extract, has high physiologically active ingredients and potent anti-oxidant and anti-inflammatory activities, suggesting its industrial application as a functional material.

• Journal of Environmental Impact Assessment
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• v.31 no.1
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• pp.1-10
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• 2022

This study was carried out to understand the water quality characteristics of the initial stormwater runoff and the origin of soluble pollutants according to various rainfall conditions from a non-point source reducing facility. The water sample from this study was collected among 10 collection facilities in the G-drainage area. Specifically, five of the collection points including #1, #5, #8, #9, and #10 were reported with unknown water inflow even during non-rain conditions. The leakage characteristics of non-point pollutants from the collection facilities were then able to identify accordingly. The water quality characteristics of the stormwater runoff from the collection facilities were strongly affected by the amounts of rainfalls. The average concentrations of EC, BOD, TOC, and TN during non-rain were found to be higher than their concentrations during rain; on the other hand, the average concentrations of DO were found to be lower than its concentrations during rain. In addition, the distribution of organic components existing in the effluent of collection facilities were identified based on the dissolved organic matter analysis. In summary, the stormwater runoff was highly affected by pollutants flowing from the surrounding environment, and the amounts of hard-to-decompose humic substances were greatly increased in the collection facilities due to rain.

• Journal of the Korean GEO-environmental Society
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• v.24 no.9
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• pp.5-13
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• 2023

Cement-based reinforcement materials, which are representative slope reinforcement materials, can cause contamination of ground and groundwater when ground injection or surface application is applied. Accordingly, slope reinforcement materials using eco-friendly biopolymers are attracting attention as a means of replacing existing materials, but the biopolymers currently used are easily dissolved when exposed to groundwater or rainfall environments, reducing strength. In order to solve this problem, the cross-linking of protein between sodium casein and Transglutaminase (TGase, C₂₀H₁₆N₄O₂S₂) was used to increase the water resistance of biopolymers, and a rainfall slope test was conducted to evaluate their usability and applicability as a slope reinforcing material. In the case of reinforcement with only sodium casein, the precipitation dissolved sodium casein, and the slope was completely destroyed in 1 hour. On the other hand, it was observed that the slope reinforced by adding a small amount of TGase (0.5%) do not collapse even after 80 hours of rainfall duration due to increased water resistance. Strength and water resistance increases due to the addition of a small amount of TGase, and its applicability as an eco-friendly reinforcement is confirmed.

• Journal of the Korean Society of Radiology
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• v.17 no.3
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• pp.449-457
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• 2023

Shielding for reducing exposure dose can make the diagnosis limited. The purpose of this study is to increase the efficiency of radiation protection and minimize the loss of image information by producing the shielding made of the water and the contrast medium which has different proportion and finding out the ideal proportion of them. Each shielding materials were made of water and water-soluble iodine contrast medium with the different proportion. The attenuation rate of absorbed dose was evaluated by the shielding materials in the plastic contents for measuring the efficiency of the radiation protection. As a result, the higher ratio of the contrast medium, the more efficient it is for radiation attenuation. The anatomical structure was observed most properly in case of the solution with 20 ml of the contrast medium and most difficultly in case of more than 60 ml of the contrast medium. In case of the signal intensity between skeleton and gas, the difference of average value had a significant as p < 0.001. Shielding with contrast medium attenuates less than the conventional shielding but in the examination for the sensitive part to radiation, it can be used to minimize the loss of the image information and reduce the exposure dose.