• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.1
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• pp.80-87
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• 2011

Panax ginseng has been used as a traditional medicine for several centuries in Korea. A laboratory experiment using methanol extracts of freeze-dried leaves and roots in the different ages of P. ginseng was conducted to determine the content of phenolics and flavonoids, antioxidant activity and cytotoxicity. The results indicate that the total phenolics level [mg ferulic acid equivalents (FAE) $kg^{-1}$ DW] was higher in leaves (22.0 to 76.3 mg $kg^{-1}$) than roots (19.0 to 28.3 mg $kg^{-1}$) of P. ginseng. The total content of phenolics in roots increased with increase in age of P. ginseng from one to six years. However, the content of phenolics in P. ginseng leaf decreased with the increase in age. Total flavonoid [mg naringin equivalents $kg^{-1}$ DW] was more detected in the leaves (30.3 to 138.6 mg $kg^{-1}$) than in the roots (0.0 to 10.6 mg $kg^{-1}$) of P. ginseng. The total flavonoid level in leaves decreased with increase in age of P. ginseng. The antioxidant potential of the methanol extracts from the plants dose-dependently increased. DPPH free radical scavenging activity was higher in leaves (36.9 to 82.8%) than in roots (14.8 to 39.4%), and in young plants than in old ones. According to 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, the methanol extracts from 5 year-root part showed the highest cytotoxicity against Calu-6, followed by 2 year- and 3 year-roots. However, the methanol extracts from 6 year- and 4 year-roots had lower cytotoxicity. Total phenolics content in both leaves and roots was highly correlated with the DPPH radical scavenging ($r^2=0.7366$ to 0.7870) and nitrite scavenging ($r^2=0.5604$ to 0.8794) activities, suggesting that they contribute to the antioxidant properties of the P. ginseng plants.

• Korean Journal of Environmental Agriculture
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• v.31 no.2
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• pp.104-112
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• 2012

BACKGROUND: Agricultural inputs (fertilizer and organic inputs) and water conditions can influence $CH_4$ and $CO_2$ emission from agricultural soils. This study was conducted to investigate the effects of agricultural inputs (fertilizer and organic inputs) under changing water regime on $CH_4$ and $CO_2$ emission from a soil in a laboratory incubation experiment. METHODS AND RESULTS: Four treatments were laid out: control without input and three type of agricultural inputs ($(NH_4)_2SO_4$, AS; pig manure compost, PMC; hairy vetch, HV). Fertilizer and organic inputs were mixed with 25 g of soil at 2.75 mg N/25 g soil (equivalent to 110 kg N/ha) in a bottle with septum, and incubated for 60 days. During the first 30-days incubation, the soil was waterlogged (1 cm of water depth) by adding distilled water weekly, and on 30 days of incubation, excess water was discarded then incubated up to 60 days without addition of water. Based on the redox potential, water regime could be classified into wetting (1 to 30 days), transition (31 to 40 days), and drying periods (41 to 60 days). Across the entire period, $CH_4$ and $CO_2$ flux ranged from 0 to 13.8 mg $CH_4$/m/day and from 0.4~1.9 g $CO_2$/m/day, and both were relatively higher in the early wetting period and the boundary between transition and drying periods. During the entire period, % loss of C relative to the initial was highest in HV (16.4%) followed by AS (8.1%), PMC (7.5%), and control (5.4%), indicating readily decomposability of HV. Accordingly, both $CH_4$ and $CO_2$ fluxes were greatest in HV treatment. Meanwhile, the lower $CH_4$ flux in AS and PMC treatments than the control was ascribed to reduction in $CH_4$ generation due to the presence of oxidized compounds such as ${SO_4}^{2-}$, $Fe^{3+}$, $Mn^{4+}$, and ${NO_3}^-$ that compete with precursors of $CH_4$ for electrons. CONCLUSION: Green manure such as HV can replace synthetic fertilizer in terms of N input, however, it may increase $CH_4$ emission from soils. Therefore, co-application of green manure and livestock manure compost needs to be considered in order to achieve satisfactory N supply and to mitigate $CH_4$ and $CO_2$ emission.

• Economic and Environmental Geology
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• v.36 no.6
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• pp.469-480
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• 2003

Laboratory leaching experiment study carried out to estimate a extent of heavy metals that could be leached out when acid rain(pH 5.0-3.0) and strong acidic solution(pH 2.5-1.0) reacted with tailings and contaminated soils from abandoned metal mines. In slightly to moderately acid conditions(pH 5.0-3.0), As, Pb and Zn dissolutions became significantly increased with decreased pH in tailing, while dissolution of these elements was very limited in contaminated soil. These results suggested that moderately acid rainwater leaches Pb, As and Zn from the tailings, while these elements would remain fixed in contaminated soil. In the pH range of 2.5-1.0(strongly acid condition), Zn, Cd and Cu concentrations of leachate rapidly increased with decreased pH in contaminated soil, while Pb, As and Co dissolutions became importantly increased in tailings. The experimental solubility of Zn. Cd and Cu was very low even at very low pH values(up to pH 1), except for CY4(Cheongyang mine). These can result from an incomplete dissolution or the presence of less soluble mineral phases. So, the solubility of heavy metals depends not only on the pH values of leachate but also on the speciation of metals associated with contaminated soils and tailings. The relative mobility of each element within failings at the pH 5.0-3.0 of the reaction solution was in the order of Pb>Zn>Cd>Co=Cu>As. In case of pH 2.5-1.0 of the reaction solution, the relative mobility of each element within contaminated soils and tailings were in the order of Zn＞Cd>Cu>Co>Pb=As for contaminated soils, and Pb>Zn>Cd>hs>Co>Cu for tailings. The obtained results could be useful for assessing the environmental effects and setting up the restoration plan in the areas.

• Applied Biological Chemistry
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• v.20 no.1
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• pp.58-65
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• 1977

A laboratory experiment was carried out with loamy paddy soily under Hooded condition to study the effects of some pesticides on the decomposition rate of urea and the transformation of nitrogen. The pesticides used in this study are ten kinds, which are usually applicable for rice cropping. The soil was treated with 200ppm of fertilizer urea-N and different levels of pesticides and then incubated at $28{\pm}1^{\circ}C$ for two weeks. The kinds of pesticides used in this study were three kinds of herbicides (2,4-D, Machete and TOK), three kinds of fungicides (Rabcide, Neo-asozine and Phenazine) at the levels of 20,100 and 200ppm and four kinds of insecticides (Birlane, Diazinon, Sumithion and Bux) at the levels of 50,250 and 500ppm. respectively. The results obtained may be summarized as follows. 1. The treatments of herbicides and fungicides show little effect on the decomposition rate of urea at the levels of 20 and 100ppm, but by the treatment of 200ppm it was retarded markedly after one day incubation aside from Rabcide and Neo-asozine. The decomposing rate of urea was inhibited weakly by the treatment with 250ppm of Sumithion and Bux, however, 500ppm of all kinds of insecticides treated in this study brought about strong inhibitory effect (over 50%) after only one day incubation. The applied urea was disappeared nearly completely in three days in all cases with and without pesticides. 2. The production of ammonium-N was increased with the increase of pesticide concentrations gradually through two weeks and otherwise in the control sample a loss of inorganic-N resulted in about 20% extent. 3. The inhibitory effect of the all applied pesticides on_the_ nitrification under flooded condition was observed markedly and may be ordered as insecticides, herbicides and fungicides according to its inhibiting action.

• Applied Biological Chemistry
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• v.20 no.1
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• pp.88-94
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• 1977

A laboratory study was made of liming on the extractability of phosphate added to the uncultivated acid soils differing in clay content. The experiments were conducted with different rates of calcium carbonate and triple superphosphate at field capacity and 50% field capacity. The concentration of extractable phosphate was greatly reduced by simultaneous addition of calcium carbonate in the loam soil. When samples of the loam soil were preincubated for ranging from 0 to 50 days in the presence of calcium carbonate prior to phosphate application, the extractable phosphate concentration increased with preincubation time, and more phosphate was extracted from the soil maintained at 50% field capacity during the incubation. However, the extractable phosphate concentration in the sandyloam soil did not change with preincubation time and was not affected by moisture status. It may be concluded that the extractability of added phosphate was influenced by not only liming time but physical properties of soil.

• Geophysics and Geophysical Exploration
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• v.15 no.4
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• pp.209-218
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• 2012

Repeatability and reproducibility in solid weight and effective porosity measurements have been discussed using 8 core samples with different diameters, lengths, rock types, and effective porosities. Further, the effect of temperature on the effective porosity measurement has been discussed as well. Effective porosity of each sample has been measured 7 times with vacuum saturation method with vacuum pressure of 1 torr and vacuum time of 80 minutes. Firstly, effective porosity of each sample is measured one by one, so that it can provide a reference value. Then for reproducibility check, effective porosity measurements with vacuum saturation of 2, 4, and 8 samples simultaneously have been performed. And finally, repeated measurements for 3 times for each sample are made for repeatability check. Average deviation from the reference set in solid weight showed 0.00 $g/cm^3$, which means perfect repeatability and reproducibility. For effective porosity, average deviations are less than 0.07% and 0.05% in repeatability and reproducibility test sets, respectively, which are in good agreement too. Most of porosities measured in reproducibility test lies within the deviation range in repeatability test sets. Thus, simultaneous vacuum saturation of several samples has little impact on the effective porosity measurement when high vacuum pressure of 1 torr is used. Air temperature can cause errors on submerged weight read and even effective porosity, because it is closely related to the temperature, density, and buoyancy of water. Consequently, for accurate measurement of effective porosity in a laboratory, efforts for maintaining air or water temperature constant during the experiment, or a temperature correction from other information are needed.

• Journal of dental hygiene science
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• v.17 no.6
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• pp.495-500
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• 2017

Hippophae rhamnoides L. (sea buckthorn) is a shrub wood that belongs to the bamboo tree family, and is rich in vitamin C, D, and E; it is referred to as a vitamin tree. It is mainly grown in the high mountains of Europe and Central Asia, and has been widely used in China and Russia as natural medicine. Recent studies have shown that it is effective in the treatment of cancer, liver diseases, cardiovascular diseases, and gastrointestinal diseases. However, results of studies on its effect on the regulation of pain are insufficient. In this study, we investigated the effect of sea buckthorn on the development and control of pain in two facial areas. The experimental animals included 7- to 8-week-old Sprague-Dawley rats (240~260 g). Formalin (5%), which is known as an inflammation inducer, was injected into the vibrissa pad or temporomandibular joints to induce orofacial acute pain. Rubbing or scraping of the region injected with formalin was regarded as a pain index, and the behavioral response was observed for 45 minutes after the injection. Sea buckthorn extract diluted to 150, 300 mg/kg (in 1 ml of distilled water) was orally administered 30 minutes prior to the acute pain. The facial pain behavior was effectively reduced in the 300 mg/kg group when compared to the control group (vehicle). Likewise, in an experiment in which formalin was injected into the temporomandibular joints, effective pain alleviation was confirmed at the same drug concentration. These results suggest that sea buckthorn extract may be useful in the development of therapeutic agents for acute inflammatory pain in the orofacial area and for controlling temporomandibular joint pain.

• Korean Journal of Plant Resources
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• v.25 no.2
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• pp.232-239
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• 2012

A laboratory experiment was conducted to determine the content of phenolics and flavonoids, antioxidant activity and cytotoxicity from methanol extracts of different plant parts of $T.$ $officinale$ F. H. Wigg. Total phenolics [mg chlorogenic acid equivalents (FAE) $kg^{-1}$ DW] was highest in flower extracts (72.0 mg $kg^{-1}$), followed by leaf, root, and stalk extracts of $T.$ $officinale$ ($p$ < 0.05). The result of total flavonoid level [mg naringin equivalents $kg^{-1}$ DW] had same tendency to differential total phenolics contents among plant parts, but showed lower ranges of amount. The antioxidant activity of the methanol extracts from all the plant parts dose-dependently increased. DPPH (1,1-diphenyl-2-picryl hydrazyl radical) free radical scavenging activity was highest in flower extracts ($IC_{50}$ value = 624.3 mg $kg^{-1}$ ), and followed by leaf, root, and stalk extracts of $T.$ $officinale$ ($p$ < 0.05). By means of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, cell viability of Calu-6 for human pulmonary carcinoma and SNU-601 for human gastric carcinoma showed the lowest $IC_{50}$ value in the flower extracts ($IC_{50}$ value = 85.7 and 311.4 mg $kg^{-1}$, respectively), indicating the highest cytotoxicity. The results suggested that total phenolics content and total flavonoids level in different plant parts of $T.$ $officinale$ were highly correlated with antioxidative ($r^2$=0.7280 to 0.9971) or with cytotoxic activities ($r^2$=0.5795 to 0.9515).

• Journal of the Korean Wood Science and Technology
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• v.15 no.2
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• pp.1-15
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• 1987

This experiment was undertaken for the purpose of investigation of relative durability about thirty sorts of the korean native wood and nine sorts of the wood destroying fungi Polystictus versicolor, Irpex consors. Poria vaporaria, Merulius lacrymans, Schizophyllum commune, Trametes pini, Lenzites betulina, Paxillus panuoides by means of a laboratory methods. The results obtained are; (from the table 2 to 10) 1. By measuring the percentage of loss in weight with regard to Polystictus versicolor, the sap wood contained in Junipeus chinesis was calculated at 18.2%, therefore it is much higher durability than any others and the sap wood contained in Pinus densiflora was measured at 44.10%, therefore it is much lower durability than any others. 2. By measuring the percentage of loss in weight with regard to Irpex consors, the heart wood contained in Butula schmidtii was calculated at 1.23%, therefore durability is very high and the heart wood contained in Quercus dentata was calculated at 26.79%, therefore durability is very low. 3. By measuring the percentage of lass in weight with regard to Lenzites betulina, the heart wood contained in Betula schmidtii was calculated at 5.33%, therefore it is much higher durability than any others and the sap wood with regard to Abies holophylla was measured at 45.48%, therefore durability is very low. 4. By measuring the percentage of loss in weight with regard to Poria vaporaria, the sap wood contained in Fraxinus rhynchophylla was calculated at 5.57%, therefore durability is very high and the sap wood contained in Paulownia coreana was calculated at 35.6%, therefore it is much lower durability than any others. 5. By measuring the percentage of loss in weight with regard to Merulius lacrymans, the heart wood contained in Castanea crenata was measured at 0.09% and in the next place, the heart wood contained in Abies holophylla calculated at 0.15% did not decay almost and the sap wood contained in Cornus controversa was measured at 32.88%, therefore it is lower durability than any others. 6. By measuring the percentage of loss in weight with regard to Schizophyllum commune, the sap wood cantained in Junipensis chinensis was calculated at 1.09%, therefore durability is very high and the sap wood contained in Populus deltoides was calculated at 36.87%, it is much lower durability than any others. 7. By measuring the percentage of loss ill weight with regard to Trametes pini, the sap wood contained in Robinia pseudo-acacia was calculated at 1.33%, therefore durability is very high and the sap wood contained in Comus controversa was calculated at 33.19%, it is much lower durability than any others. 8. By measuring the percentage of loss ill weight with regard to Paxillus panuoides. the heart wood contained in Zelkova serrata was calculated at 1.73%, therefore durability is very high and the sap wood contained in Populus deltoides was calculated at 42.30%, therefore durability in very low. 9. By measuring the percentage of loss in weight with regard to Dardalea quercina, the heart wood contained in Castanea crenata was calculated at 0.92%, therefore durability is very high and the sap wood contained in Cornus controversa was calculated at 32.00% therefore durability is very low. The above results are summarized as follows 1. Durability between the heart wood and the soft wood find that it is nonsignificant, while durability is higher heart wood than sap wood. 2. Special sorts including in the element like Castanea cenata, Robinia pseudo-acacia, Juniperus chinensis and heart wood like Betula schmiditii and Styrax obasia are highly durable and soft wood like Cornus controversa, Populus davidiana, Salix koreensis, Celtis jessensis are lowly durable in general. 3. Among the wood destroying fungi Paxillus panuoides is highly durable and as follows. Poria vaporaria, Lenzites betulina and the Daedalea quercina is less in general and Irpex consors, Mersulius lacrymans are a middle degree.

• Journal of The Korean Association For Science Education
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• v.31 no.6
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• pp.864-875
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• 2011

The purpose of this study was to investigate high school students' understanding of acid-base related concepts using three different titration technologies. The test population was composed of 209 students from three classes in the 10th grade. The different titration experiments using indicator, or pH-meter or MBL were performed in each class unit, respectively. The analyses of the effect on the understanding of different titration technologies were carried out by comparing the mean scores of the concept test taken before and after the titration for the three groups. The results of the acid-base related concept test indicated that statistically significant effects on the understanding of the concepts were shown by all groups. Comparing the effect on the comprehension of the three groups, the MBL group showed the most significant effect, while the pH-meter group showed the least significant. It was also attempted to analyze the effect on comprehension of the concepts by the cognitive and the motivational levels of students. This study revealed that the students in the formal operation stage showed higher understanding of the acidbase related concepts, while those in the concrete operation stage showed lower comprehension. It was also shown that the students at the active motivational level scored higher in comprehension than those who had a low score. The results of this study implied that each group showed differently enhanced comprehension of concepts by titration technologies. Therefore, teachers need to promote an appropriate experiment technology for the cognitive and motivational levels of students as well as try to help students express freely their own perspectives.