• Journal of Ecology and Environment
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• v.45 no.1
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• pp.1-9
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• 2021

Background: Abandoned coal piles after the closure of mines have a potential negative influence on the environment, such as soil acidification and heavy metal contamination. Therefore, revegetation by efficient species is required. For this, we wanted to identify the role of Silene acaulis in the succession of coal piles as a pioneer and a nurse plant. S. acaulis is a well-studied cushion plant living in the Arctic and alpine environments in the northern hemisphere. It has a highly compact cushion-like form and hosts more plant species under its canopy by ameliorating stressful microhabitats. In this research, we surveyed vegetation cover on open plots and co-occurring species within S. acaulis cushions in coal piles with different slope aspects and a control site where no coal was found. The plant cover and the similarity of communities among sites were compared. Also, the interaction effects of S. acaulis were assessed by rarefaction curves. Results: S. acaulis was a dominant species with the highest cover (6.7%) on the coal piles and occurred with other well-known pioneer species. Plant communities on the coal piles were significantly different from the control site. We found that the pioneer species S. acaulis showed facilitation, neutral, and competition effect in the north-east facing slope, the south-east facing slope, and the flat ground, respectively. This result was consistent with the stress gradient hypothesis because the facilitation only occurred on the north-east facing slope, which was the most stressed condition, although all the interactions observed were not statistically significant. Conclusions: S. acaulis was a dominant pioneer plant in the succession of coal piles. The interaction effect of S. acaulis on other species depended on the slope and its direction on the coal piles. Overall, it plays an important role in the succession of coal piles in the High Arctic, Svalbard.

• Geotechnical Engineering
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• v.12 no.3
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• pp.127-148
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• 1996

Recently, foundations of heavy structures such as bridge abutments have been built on slopes or near the crest of slopes at an increasing rate. Because the bearing capacity of such foundations is considerably lower than the bearing capacity of the same soil on a level ground, deep footings such as piles and caissons are often used. However, the costs of such methods are generally very high. One of the new techniques to overcome the problem is to place reinforcing members such as geosynthetics or metal strips horizontally at some depths beneath the footings. Rational methods of analysis to predict the bearing capacity of footings in reinforced slopes are therefore needed. This paper proposes an analytical method for estimating the increase in bearing capacity gained from the included horizontal strips or ties of tensile reinforcing in the foundation soil below the footing built near the crest of a slope. A failure mechanism, including the concept of'wide slab effect', adopted in the present study for analyzing the bearing capacity of foundations in reinforced slopes, is established through the observed model test behaviors described by Binquet SE Lee and Huang et al, and the Boussinesq solutions. The analytical results are then compared with the experimental data described in the paper by Huang et al. Also in order to properly evaluate the soil reinforcement interaction, typical pullout test values of the apparent friction coefficient, which usually vary with depths owing to both the increase of the shearing volume and the increase in local stress caused by soil dilatancy, are analyzed and related functionally. Furthermore, analytical parametric studies are carried out to investigate the effect and significance of various pertinent parameters associated with design of reinforced slope foundations. Keywords : Bearing capacity, Reinforced slope, Slab effect, Friction coefficient.

• Composites Research
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• v.29 no.3
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• pp.111-116
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• 2016

The tilting pad journal bearing for the turbo compressor application has a role to support high speed and heavy loading rotor. White metal has been widely used for the bearing material but the conventional bearing is immediately suspended and induces serious serious damage to the rotor under the unexpected oil cut situation or the insufficient oil film formation. The carbon fiber reinforced composite having high specific stiffness, specific strength and excellent tribological characteristics can solve these seizure problems. In this work, the study on the durability of high thermal resistance carbon fiber/epoxy composite tilting pad journal bearing under oil cut situation was conducted. The material properties of the composite materials including tensile, compressive and interlaminar properties were measured at room and high temperature of oil cut situation. To investigate the possibility of failure of composite tilting pad journal bearing under oil cut situation, the stress distribution of the composite bearing was analyzed via finite element analysis and the Tsai-Wu Failure index was calculated. To verify the failure analysis results, the oil cut tests for the composite tilting pad journal bearing were conducted using industrial test bench.

• Korean Journal of Clinical Laboratory Science
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• v.52 no.2
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• pp.150-157
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• 2020

The protective effects of a Celastrus orbiculatus Thunb (CO) extract against manganese dioxide (MnO₂)-induced cytotoxicity in cultured C6 glioma cells were examined. This study assessed the antioxidative effects, including the suppressive ability of lipid peroxidation (LP), the inhibitory ability of xanthine oxidase (XO), and the cell viability. MnO₂ decreased the cell viability remarkably in a dose-dependent manner. The XTT₅₀ value was determined to be 146.7 μM in these cultures. The cytotoxicity of MnO₂ was calculated to be mid-toxic using Borenfreund and Puerner's toxic criteria. Kaempferol (KAE) increased the cell viability damaged by MnO₂-induced cytotoxicity significantly. Regarding the protective effects of the CO extract on MnO₂-induced cytotoxicity, the CO extract increased cell viability significantly compared to the MnO₂-treated group. The CO extract also had inhibitory abilities against lipid peroxidation (LP) and xanthine oxidase (XO). From these findings, oxidative stress is involved in the cytotoxicity of MnO₂. The CO extract effectively blocked the cytotoxicity induced by MnO₂ via its antioxidative effects. Conclusively, natural resources, such as the CO extract, might be a useful agent for the diminution or improvement of the heavy metal cytotoxicity correlated with disease through oxidative stress, such as MnO₂, a Parkinsonism inducer.

• Journal of Nutrition and Health
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• v.55 no.4
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• pp.430-440
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• 2022

Selenium is an important trace mineral that plays an essential role in maintaining the body's immunity with oxidative stress defense and antioxidant activity, immunity, thyroid hormone control, defense against drug or heavy metal harm, and reducing the risk of chronic diseases. A selenium deficiency increases the risk of various chronic diseases, such as cancer, cardiovascular disease, diabetes, neurological disease, osteoarthritis, muscle necrosis and weakness, thyroid disease, and inflammatory diseases. This paper explains the criteria for establishing and revising selenium in the 2020 Dietary Reference Intake for Koreans (KDRIs) and reviews the current status of the selenium database and suggestions for setting the 2025 KDRIs in the future. In the 2020 KDRIs, the selenium intake with the maximum plasma selenoprotein P level was used as the criteria. The weight and coefficient of the variation were applied to the Chinese' reported values. Compared to 2015 KDRIs, there were some revisions in the selenium dietary reference intakes by gender and age according to the change in reference weight. To improve and revise selenium dietary reference intakes in the future, a selenium intervention study is needed to determine the maximum level of plasma selenoprotein P in Koreans. In addition, a revision of the selenium database of the nutritional assessment program (CAN-Pro 5.0) is needed. An analysis of the selenium content of foods should be expanded to assess the selenium intake accurately. In addition, research on the relationship between selenium intake and the biological indicators in the body is required for healthy people and subjects of special environments, such as patients and athletes with various oxidative stress.

• Journal of Sericultural and Entomological Science
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• v.50 no.1
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• pp.10-14
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• 2012

Resveratrol is naturally occurring phytoalexin compounds produced by grape berries, peanuts, pine tree, mulberry fruits and their products in response to stress such as fungal infection, heavy metal ions or UV irradiation. The objective of this study was to determine resveratrol contents in wild-type mulberry leaves (Morus alba L., M. bombycis Koidz, and M. Lhou (Ser.) Koidz) collected from Won-ju, In-je and Yang-yang regions, Gangwon province, Korea. Resveratrol contents in wild-type mulberry leaves were higher in Autumn's than in Spring's, and higher than 16 cultivar's. Among the samples, 'No. 3', collected from Won-ju region and 'No. 7' collected from In-je showed high resveratrol contents of 539 and $491{\mu}g$/100 g DW (dry weight; DW), respectively, through the collection time. Therefore, two mulberry trees might be promising as potent resources for mulberry breeding and functional material development.

• The Korean Journal of Malacology
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• v.30 no.1
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• pp.41-49
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• 2014

This study was conducted to investigate the effects of cadmium (Cd) exposure on biochemical factors in the hemolymph and hepatopancreas of the abalone, Haliotis discus hannai. The abalone were exposed to 0, 5, 10, 20 and 40 ${\mu}g/L$ Cd for 4 weeks. The phenoloxidase (PO) activity was decreased in hemolymph of abalone exposed to 40 Cd ${\mu}g/L$ for 4 weeks compared to the control (P < 0.05). The hemolymph enzymes, alkaline phosphatase (ALP), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities were markedly elevated in 40 Cd ${\mu}g/L$ after 4 weeks. The hemolymph calcium concentrations were significantly decreased in 20 and 40 Cd ${\mu}g/L$ for 4 weeks. Hepatopancreas superoxide dismutase (SOD) and catalase (CAT) activities were significantly increased by Cd. SOD was increased in both 20 and 40 Cd ${\mu}g/L$ and CAT, in 40 Cd ${\mu}g/L$ after 2 weeks (P < 0.05). These results suggested that the abalone SOD and CAT including PO may serve as a protective mechanism against oxidative stress by Cd. We conclude that a Cd concentration, 40 ${\mu}g/L$ in water may curtail hemolymph homeostasis and anti-oxidative reactions in abalone hepatopancreas. From these results, these biochemical factors may represent a convenient method of monitoring heavy metal pollution in coastal areas.

• Journal of the Korean Ceramic Society
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• v.41 no.3
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• pp.221-228
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• 2004

Basic properties of artificial lightweight aggregate by using waste dusts and strength properties of LWA concrete were studied. Bulk specific gravity and water absorption of artificial lightweight aggregates varied from 1.4 to 1.7 and 13 to 16%, respectively. Crushing ratio of artificial lightweight aggregate was above 10% higher than that of crushed stone or gravel. As a result of TCLP leaching test, the leaching amount of tested heavy metal element was below the leaching standard of hazardous material. Slump, compressive strength and stress-strain properties of LWA concrete made of artificial lightweight aggregate were tested. Concrete samples derived from LWA substitution ratio of 30 vol% and W/C ratio of 45 wt% showed the best properties overall. Thermal insulation and sound insulation characteristics of light weight concrete panel with the optimum concrete proportion were tested. Average overall heat transmission of 3.293W/㎡$^{\circ}C$ was observed. It was higher by about 15% than those of normal concrete made by crushed stone. Sound transmission loss of 50.9 ㏈ in frequency of 500 ㎐ was observed. It was higher by about 13% than standard transmission loss.

• Korean Journal of Food Science and Technology
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• v.35 no.5
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• pp.764-768
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• 2003

Resveratrol is natually occurring phytoalexin compounds produced by grape berries, peanuts, and their products in response to stress such as fungal infection, heavy metal ions or UV irradiation. The objective of this study was to develop a reliable high-performance liquid chromatographic method for the quantitative determination of trans-resveratrol in grape and its products. The trans-resveratrol was separated isocratically on Nucleosil 100-5 C18 column, using a mobile phase containing acetonitrile : water (40 : 60, v/v), detected by UV detector at 306 nm and the flow rate was 0.3 mL/min. Under this analytical condition, the recoveries of trans-resveratrol in grape, wine, and grape juice were 92.35, 104.72, and 91.08, respectively. Limit of detection in grape, wine, and grape juice were 14.5 ng/g, 3.62 ng/mL, and 4.02 ng/mL. Also, limit of quantitation in grape, wine, and grape juice were 14.8 ng/g, 3.69 ng/mL, and 4.10 ng/mL. Assay values of 32 grape varieties, 9 wines, and 9 grape juices were ranged from trace amount to $207.1\;{\mu}g/100\;g$, from 5.4 to $275.7\;{\mu}g/L$, and from 63.3 to $751.6\;{\mu}g/L$, respectively.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.31 no.2 s.51
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• pp.197-206
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• 2005

In the present study, the Chuncheon buckwheat extracts prepared from its seed coats, seeds and stems were used to determine anti-oxidative effects, the content of rutin and phytic acid, and the protective role against cadmium at the cellular level. futhermore, it was evaluated whether the buckwheat, mainly known as a healthy food source, might be applicable to functional cosmetics. Up to $100 {\mu}g/mL$ of the extract was not toxic in HaCaT and B16F10 cell lines using MTT assay. The anti-oxidative capacity of superoxide radicals was shown in seed coats extracts > stem extracts=seed extracts. Although its content of rutin, known as one of effective anti-oxidants, mainly exists in the stem, any extract did not eliminate hydroxyl radicals. Phytic acid, known as a heavy metal-chelate agent, was highly concentrated in the stem. The Chuncheon buckwheat extract had $10\%$ protective effect against the treatment of $50{\mu}M$ cadmium at which $50\%$ of HaCaT cells survived. Confocal laser scanning microscope revealed the intracellular generation of reactive oxygen species (ROS) by cadmium treatment. Finally, we identified that the stem extract had the most protective effect on the elimination of ROS.