• The Journal of Engineering Geology
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• v.31 no.2
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• pp.187-197
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• 2021

Clay mineral content of weathered zone is a key parameter for landslide studies. Electrical resistivity tomography is usually performed to delineate the geometry of complex landslides and to identify the sliding surface. In clay-bearing weathered zone, parallel resistivity Archie equation is employed to investigate the effect of conductivity added (resistivity reduced) by clay minerals of kaolinite and montmorillonite, which is dependent on their specific surface area and cation exchange capacities (CEC). A decrease of overall resistivity and apparent formation factor is observed with increasing pore-water resistivity, significantly in montmorillonite. Formation factor is found decreased with increasing porosity and decreasing cementation factor. Parallel Archie equation was applied to the electrical resistivity data from the test area (Sinjindo-ri, Taean-gun, Chungcheongnam-do, Korea) which experienced land creeping in the year of 2014. A panel test with varying clay-mineral contents provides the best fit section when the theoretical section constructed with the assumed contents approaches the field section, from which the clay-mineral content of the weathered zone is estimated to be approximately 10%. Resistivity interpretation schemes including the clay mineral contents for land creeping studies explored in this paper can be challenged more when porosity, saturation, and pore-water resistivity are provided and they are included in the numerical resistivity modeling.

• Journal of Korean Society of Water and Wastewater
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• v.35 no.6
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• pp.465-476
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• 2021

Scale and rust generation in water pipes is a common phenomenon when cast iron water pipes have been used for a long time. A physical water treatment device is known among various means for suppressing rust in a water pipe, and a zinc ionization device for putting zinc metal into a pipe and emitting the zinc cation into water is one of such devices. This research measured the amount of zinc ion generated, which is known to exhibit an effect of inhibiting rust and scale generation in a pipe, and examined the scale and rust inhibition effect of the ionization device installed for ground or building water supply. In the case of distilled water, the concentration of zinc ion increased by circulating water in the ionization device several times, and it was verified to be hundreds of ㎍/L, and in the case of discharging ground or tap water, it was verified to be tens of ㎍/L. In addition, a verification pipe was installed to confirm the change inside the pipe before and after installation of the zinc ionization device, and the internal condition of the pipe was observed 3 months to several years after installation. It was confirmed that the corrosion area of the surface of the pipe was no longer increased by installing a corrosion inhibitor, and if the pipe was already filled with corrosion products, the amount of corrosion products gradually decreased every year after installation. The phenomenon of fewer corrosion products could be interpreted as expanding the space in the pipe due to the corrosion product as Fe₂O₃ adhered to the inner surface of the pipe and turned into a smaller black Fe₃O₄. In addition, we found that scale such as CaCO₃ together in the corrosion by-products gradually decreased with the attachment of the ionization device.

• Journal of the Korean Chemical Society
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• v.66 no.3
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• pp.185-193
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• 2022

The theoretical investigation has been performed to predict thermodynamic stability, density, detonation velocity, and detonation pressure of energetic salts produced by pairing of nitrogen-rich anions (tetrazine, oxadiazole etc.) and cations (NH₃OH⁺, NH₂NH₃⁺, CH₉N₆⁺, C₂H₆N₅⁺). All possible geometries and the binding energy for the trigger bond of energetic salts have been optimized at the B3LYP/cc-pVDZ level of theory. The detonation velocity and detonation pressure have been calculated using Kamlet-Jacobs equation, while enthalpy has been predicted at the G2MP2 level of theory. The predicted results reveal that the energetic salts including small sized NH₃OH⁺(1) and NH₂NH₃⁺(2) cations increase detonation property. And also the energetic salts including more amino group (-NH₂) such as CH₉N₆⁺(3) cation increase thermodynamic stability. These results provide basic information for the development the high energy density materials (HEDMs).

• Economic and Environmental Geology
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• v.54 no.6
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• pp.699-707
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• 2021

Hwajinpo Lagoon, located on the eastern coast of Korea, is a unique environment where freshwater and saltwater are mixed. Systematic management of the lagoon is required because it is a biodiversity-rich and area of high conservation value. The existing environment of the lagoon was evaluated by identifying the distribution of the groundwater level and groundwater flow characteristics. In addition, hydrogeochemical fluctuations were analyzed to determine the effect of seawater intrusion into the aquifer. The results demonstrate that the freshwater-saltwater interface is distributed throughout the aquifer and rises when water of the lagoon evaporates due to prolonged periods of low rainfall and high temperature, thereby increasing the possibility of seawater inflow through groundwater. As for the ionic delta properties (difference between the measured and theoretical concentration of mixed waters), it was estimated that the cation-exchange and precipitation reactions occurred in the aquifer due to seawater intrusion. The ratio of seawater mixed at each point was calculated, using oxygen isotopes and chloride as tracers, resulting in an average of 0.3 and a maximum of 0.87. The overall seawater mixing ratio appears to be distributed according to the distance from the coast. However, some of the results were deviated from the theoretical expectations and reflected the characteristics of the nearby aquifers. Further research on seasonal changes and simulation of seawater intrusion mechanisms is required for specific analysis.

• Economic and Environmental Geology
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• v.55 no.3
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• pp.219-229
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• 2022

Bentonite is being considered as a candidate for buffer material in geological disposal systems for high-level radioactive wastes. In this study, the effect of cement-bentonite interactions on bentonite alteration was investigated by reviewing the literature on studies of cement-bentonite interactions. The major bentonite alteration by hyperalkaline fluids produced by the interaction of cementitious materials with groundwater includes cation exchange, montmorillonite dissolution, secondary mineral precipitation, and illitization. When the hyperalkaline leachate from the reaction of the cementitious material with the groundwater comes into contact with bentonite, montmorillonite, the main component of bentonite, is dissolved and a small amount of secondary minerals such as zeolite, calcium silicate hydrate, and calcite is produced. When montmorillonite is continuously dissolved, the physicochemical properties of bentonite may change, which may ultimately causes changes in bentonite performance as a buffer material such as adsorption capacity, swelling capacity, and hydraulic conductivity. In addition, the bentonite alteration is affected by various factors such as temperature, reaction period, pressure, composition of pore water, bentonite constituent minerals, chemical composition of montmorillonite, and types of interlayer cations. This study can be used as basic information for the long-term stability verification study of the buffer material in the geological disposal system for high-level radioactive wastes.

• Herbal Formula Science
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• v.30 no.2
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• pp.37-44
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• 2022

Objectives : The purpose of this study was to examine the effects of Alisma canaliculatum Extract (ACE) on pacemaker potentials of small and large intestinal interstitial Cells of Cajal (ICC) in mice. Methods : We used enzymatic digestions to dissociate the ICC in the small and large intestine in mice. The whole-cell patch-clamp method was used to record pacemaker potentials in ICC. Results : 1. The ICC generated the pacemaker potentials in small intestine in mice. ACE (0.1-1mg/ml) induced membrane depolarization and decreased frequency with concentration-dependent manners. 2. Pretreatment with a Ca²⁺ free solution, Na⁺ 5 mM solution or 2-APB, a nonselective cation channel blocker, stopped the small intestinal ICC pacemaker potentials. In the case of Ca²⁺-free solution, Na⁺ 5 mM solution or 2-APB, ACE had no effects on the membrane depolarizations in small intestinal ICC. 3. The ICC generated the pacemaker potentials in large intestine in mice. Membrane depolarization appears regularly in the small intestine, but irregularly in the large intestine. ACE induced membrane depolarization (0.1-1mg/ml) and increased frequency (0.1-0.5mg/ml). 4. Pretreatment with a Ca²⁺ free solution, Na⁺ 5 mM solution or 2-APB, stopped the large intestinal ICC pacemaker potentials. In the case of Ca²⁺-free solution, Na⁺ 5 mM solution or 2-APB, ACE depolarized the membrane depolarizations in large intestinal ICC. 5. In mice, intestinal transit rate (ITR) values were dose-dependently decreased by the intragastric administration of ACE. Conclusions : These results suggest that ACE can regulate the pacemaker activity of ICC and the reaction by ACE is different from the small and large intestinal ICC, and the control of the intestinal motion by ACE may be caused by many complex processes.

• Journal of Korean Society of Forest Science
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• v.111 no.4
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• pp.538-547
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• 2022

In this study, the population and community structure of Berchemia berchemiaefolia stands located at Mt. Naeyon (Gyeongbuk, Korea) were quantified, and multivariate analysis was done to determine the correlations between vegetation group types and environmental factors and to have reference data for the conservation and restoration of this species. In total, there were 164 B. berchemiaefolia trees in Mt. Naeyon. The average DBH of the trees was 24.5 cm, forming a normal distribution. It rarely appeared in an understory vegetation height of 3 m. About37.1% of the trees were branched. B. berchemiaefolia stands were classified into two groups: B. berchemiaefolia-Quercus serrata community and B. berchemiaefolia-Carpinus laxiflora community. Canopy gap, organic matter, exchangeable Ca, and cation exchange capacity were the major site characteristics affecting the distribution pattern of the stands. Currently, B. berchemiaefolia trees dominate in Mt. Naeyon, but depending on different habitat positions, the species was in a natural successional stage to C. laxiflora or C. cordata, which is a shade-tolerant species.

• The Korea Journal of Herbology
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• v.29 no.4
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• pp.53-59
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• 2014

Objectives : The purpose of this study was verification of the anti-inflammation and anti-oxidant effect of Cheongungdajosan-gamibang extract (CG) in mouse macrophage, RAW 264.7 cells. Methods : We have basically using LPS-stimulated RAW 264.7 cells. The cell toxicity was determined by MTT assay. To evaluate the anti-inflammatory effect of Cheongungdajosan-gamibang, amount of nitric oxide(NO) was measured using the NO detection kit and the IL-$1{\beta}$, IL-6 and TNF-${\alpha}$ expression was measured by reverse transcriptase polymerase chain reaction (RT-PCR). Also, free radical scavenging assay has tested for DPPH and ABTS radical activity as well as the contents of total polyphenol. Results : In this study, 96.6% or higher cell viability was observed in all tested groups from 1, 10, $100{\mu}/m{\ell}$ in RAW 264.7 cells. The RAW 264.7 cells were induced by lipopolysaccharide (LPS) and CG 1, 10, $100{\mu}/m{\ell}$. The CG decreased nitric oxide (NO) production activity dose dependently, especially at $100{\mu}/m{\ell}$ of 55%. The production of IL-$1{\beta}$, IL-6 and TNF-${\alpha}$ were decreased by 51%, 78% and 35% in CG treated $100{\mu}g/m{\ell}$. CG showed dose-dependent suppression activity of reactive oxygen species (ROS) production, especially at $100{\mu}g/m{\ell}$ of 37%. DPPH radical scavenging activity and ABTS cation decolorization were activated over 86% and 88% in CG at $1,000{\mu}g/m{\ell}$ concentration. Conclusions : According to the results, we thought that CG showed anti-inflammatory and antioxidant activities on the RAW 264.7 cells in mouse macrophage. Therefore, this research is expected to provide the fundamental data about the natural material analysis of relating to the anti-inflammation and antioxidant.

• Korean Journal of Food Science and Technology
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• v.54 no.4
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• pp.445-454
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• 2022

This study aimed to improve the physiological activity of onion juice via lactic acid bacterial fermentation. Seven types of lactic acid bacteria were used for the fermentation of onion juice. The pH and sugar content of the onion juice decreased, while its titratable acidity increased after lactic acid bacteria fermentation, and the cell count of lactic acid bacteria was 7.31-10.40 log CFU/mL. The total free sugar content decreased, while the total organic acid content increased in the fermented onion juice. Quercetin content of the fermented juice was 0.13-0.53 mg/kg. The total polyphenol and flavonoid contents increased after fermentation. Additionally, the 2,2-diphenyl-1-picryl-hydrazyl-hydrate free radical and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonate) radical cation scavenging activities were increased by fermentation. Overall, lactic acid bacteria fermentation of onion juice enhanced its physiological activity. Based on these findings, Bifidobacterium breve KCTC 3441 was selected as the onion juice fermentation strain.

• Journal of Life Science
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• v.32 no.2
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• pp.155-160
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• 2022

Kenaf (Hibiscus cannabinus L.), one of the four major fiber crops, is attracting attention for its efficient CO₂-absorbing ability and versatility for producing daily supplies, including textiles. In Korea, a new cultivar 'Jangdae' was established in 2013. The ease of cultivation and seed gathering of 'Jangdae' has led to its nationwide cultivation. However, evaluation of the bioactivities of the different parts of kenaf, and especially the 'Jangdae' cultivar, remains rudimentary. In this study, the antithrombosis and antioxidant activities of extracts prepared from different parts of the 'Jangdae' cultivar were evaluated by determining their effects on blood clot formation. Extracts prepared from seeds (HC-SD), seedpods (HC-SP), leaves (HC-L), stems (HC-S), and roots (HC-R) of the 'Jangdae' cultivar strongly inhibited blood clot formation. In particular, the HC-SD, HC-SP, and HC-S extracts showed strong inhibition against the coagulation factors prothrombin, and thrombin. The HC-SP extract showed strong antioxidant activities, such as scavenging ability against DPPH anion, ABTS cation, nitrite, and reducing power. Since blood clot formation is closely related to oxidative stress, the HC-SP extract could be developed as a novel anticoagulation and antioxidant resource. This is the first report of the antithrombosis activities of different parts of H. cannabinus L. cv. 'Jangdae'.