• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.708-718
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• 2020

Offensive odor is recognized as a social environmental problem due to its olfactory effects. Ammonia(NH₃), hydrogen sulfide(H₂S) and benzene(C₆H₆) are produced from various petrochemical plants, public sewage treatment plants, public livestock wastes, and food waste disposal facilities in large quantities. Therefore efficient decomposition of offensive odor is needed. In this study, the removal efficiency of atmospheric-pressure plasma operating at an ambient condition was investigated by evaluating the concentrations at upflow and downflow between the plasma reactor. The decomposition of offensive odor using plasma is based on the mechanism of photochemical oxidation of offensive odor using free radical and ozone(O₃) generated when discharging plasma, which enables the decomposition of offensive odor at ordinary temperature and has the advantage of no secondary pollutants. As a result, all three odor substances were completely decontaminated within 1 minute as soon as discharging the plasma up to 500 W. This result confirms that high concentration odors or mixed odor materials can be reduced using atmospheric-pressure plasma.

• Economic and Environmental Geology
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• v.38 no.5 s.174
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• pp.547-561
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• 2005

General characteristics of groundwater contamination by As were reviewed with several recent researches, and its occurrence in groundwater of Korea was investigated based on a ffw previous studies and a groundwater quality survey in Nonsan and Geumsan areas. In Bangladesh, which has been known as the most serious arsenic calamity country, about $28\%$ of the shallow groundwaters exceeded the Bangladesh drinking water standard, $50{\mu}g/L$, and it was estimated that about 28 million people were exposed to concentrations greater than the standard. Groundwater was characterized by circum-neutral pH with a moderate to strong reducing conditions. Low concentrations of $SO_4^{2-}$ and $NO_3^-$, and high contents of dissolved organic carbon (DOC) and $NH_4^+$ were typical chemical characteristics. Total As concentrations were enriched in the Holocene alluvial aquifers with a dominance of As(III) species. It was generally agreed that reductive dissolution of Fe oxyhydroxides was the main mechanism for the release of As into groundwater coupling with the presence of organic matters and microbial activities as principal factors. A new model has also been suggested to explain how arsenic can naturally contaminate groundwaters far from the ultimate source with transport of As by active tectonic uplift and glaciatiion during Pleistocene, chemical weathering and deposition, and microbial reaction processes. In Korea, it has not been reported to be so serious As contamination, and from the national groundwater quality monitoring survey, only about $1\%$ of grounwaters have concentrations higher than $10{\mu}g/:L.$ However, it was revealed that $19.3\%$ of mineral waters, and $7\%$ of tube-well waters from Nonsan and Geumsan areas contained As concentrations above $10{\mu}g/:L.$. Also, percentages exceeding this value during detailed groundwater quality surveys were $36\%\;and\;22\%$ from Jeonnam and Ulsan areas, respectively, indicating As enrichment possibly by geological factors and local mineralization. Further systematic researches need to proceed in areas potential to As contamination such as mineralized, metasedimentary rock-based, alluvial, and acid sulfate soil areas. Prior to that, it is required to understand various geochemical and microbial processes, and groundwater flow characteristics affecting the behavior of As.

• Korean Journal of Environmental Biology
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• v.30 no.2
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• pp.98-106
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• 2012

The chlorophyll fluorescence and photosynthetic $CO_2$ fixation capacity of leaves from three major crop trees found on Jeju Island, Camellia sinensis L., Camellia japonica L., and Citrus unshiu M., were analyzed. The photosynthetic $CO_2$ fixation rate of C. sinensis was similar to that of C. unshiu, and much higher than that of C. japonica which belongs to the same genus. Stomatal conductance in the three species was high at dawn and low during daytime. The intercellular $CO_2$ concentration of the three species was also high at dawn and decreased at midday. The transpiration rate showed an opposite trend from the intercellular $CO_2$ concentration. The photochemical efficiencies of PSII (Fv/Fm) in C. sinensis were slightly lower at midday compared to the level at dawn and/or dusk. The decline in Fv/Fm of C. sinensis at midday was much smaller than that of C. japonica. These results indicate that C. sinensis is better acclimated to high levels of radiation under natural conditions in late summer, although its PSII reaction center was inhibited by strong radiation. Of the chlorophyll fluorescence parameters in the species, the RC/CS decreased significantly while the ABS/RC, TRo/RC, ETo/RC, and DIo/RC increased significantly at midday in late summer. However, C. unshiu did not show significant changes in these values depending on the time of day. Among the three species, the daily $CO_2$ fixation rate in C. sinensis ($320.1mmol\;m^{-2}d^{-1}$) was the highest, followed by that of C. unshiu ($292.5mmol\;m^{-2}d^{-1}$) and C. japonica ($244.8mmol\;m^{-2}d^{-1}$). Thus, C. sinensis may be a valuable crop tree in terms of the uptake of $CO_2$ under natural field conditions.

• Economic and Environmental Geology
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• v.44 no.5
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• pp.373-386
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• 2011

Geochemical study was performed on black slates and interbedded U-bearing coaly slates in Deokpyeongri area, the representative uranium mineralized district of the Ogcheon Metamorphic Belt, to discuss the genetic environments of the uranium deposit. REE concentration (254 ppm) of the black slates is higher than that (169 ppm) of the coaly slates and NASC-normalized REE patterns of the coaly slates show remarkable positive Eu anomaly. l11e redox-sensitive trace elements such as V, Cr, Co, Ni, Mo and U in the coaly slates are highly enriched compared to the black slates, especially for V of 24 times, Mo of 62 times, and U of 60 times. In additions, Pd and Pt are also enriched in the coaly slates. Positive Eu anomaly and the noticeable enrichment of the elements listed above compared to those of NASC indicate that those elements were not derived from common seawater but deposited under high temperature and reducing environment of submarine hydrothermal activities. Wide compositional ranges of major elements ($SiO_2/Al_2O_3$: 3.98~11.88, $Al_2O_3/Na_2O$: 25.6~139.06, $K_2O/Na_2O$: 6.80~46.85) also suggest that the source rocks of the sediments are mixtures of sedimentary rocks and igneous rocks. Higher sulfur contents in the coaly slates, 2.6 wt.%, than those in the black slates, 0.6 wt.% also indicates that the former was influenced by hydrothermal activities containing much sulfur. These geochemical characteristics are similar to the genetic environments of South China type PGE deposits (Mo-Ni-Zn-PGE) which is geotectonically correlated with the Ogcheon Metamorphic Belt and is known as sedimentary-exhalative deposits. In conclusions, the uranium and other metallic elements mineralization seems to have occurred in the sedimentary basin that was affected by submarine hydrothermal activities and rich in organic materials under oxygen-poor environments as well.

• Horticultural Science & Technology
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• v.35 no.1
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• pp.1-10
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• 2017

We investigated growth, clove development, and photosystem II activity in garlic (Allium sativum L.) grown under different day/night temperature regimes using Soil-Plant-Atmosphere - Research (SPAR) chambers to determine the optimum cultivation temperature and to assess the impact of temperature stress on garlic. In the early stages of growth, plant growth increased markedly with temperature. At harvest time, however, the pseudostem diameter decreased significantly under a relatively low day/night temperature range ($14/10-17/12^{\circ}C$), suggesting that these temperature conditions favor regular bulb growth. At harvest time, the bulb diameter and height were great at $14/10-23/18^{\circ}C$, whereas the bulb fresh weight and number of cloves per bulb were greatest at $17/12-20/15^{\circ}C$. However, the number of regularly developed cloves per bulb was highest at the relatively low temperature range of $14/10-17/12^{\circ}C$, as were the clove length and fresh weight. The photochemical efficiency ($F_v/F_m$) and potential photochemical efficiency ($F_v/F_o$) of photosystem II in the leaves of garlic plants were higher at $14/10-20/15^{\circ}C$ and lower at temperatures below $14/10^{\circ}C$ or above $20/15^{\circ}C$, implying that the $14/10-20/15^{\circ}C$ temperature range is favorable, whereas temperatures outside this range are stressful for garlic growth. Furthermore, at temperatures above $20/15^{\circ}C$, secondary growth of garlic, defined as lateral bud differentiation into secondary plants, continuous growth of the cloves of the primary plants, or the growth of bulbil buds into secondary plants, was enhanced. Therefore, to achieve commercial production of fresh scapes and bulbs of garlic, it may be better to grow garlic at relatively low temperature ranges of $14/10-17/12^{\circ}C$.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.4
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• pp.357-365
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• 2016

The effects of elevated atmospheric $CO_2$ on photosynthesis and growth of Chinese cabbage (Brassica campestris subsp. napus var. pekinensis) were investigated to predict productivity in highland cropping in an environment where $CO_2$ levels are increasing. Vegetative growth, based on fresh weight of the aerial part, and leaf characteristics (number, area, length, and width) of Chinese cabbage grown for 5 weeks, increased significantly under elevated $CO_2$ ($800{\mu}mol{\cdot}mol^{-1}$) compared to ambient $CO_2$ ($400{\mu}mol{\cdot}mol^{-1}$). The photosynthetic rate (A), stomatal conductance ($g_s$), and water use efficiency (WUE) increased, although the transpiration rate (E) decreased, under elevated atmospheric $CO_2$. The photosynthetic light-response parameters, the maximum photosynthetic rate ($A_{max}$) and apparent quantum yield (${\varphi}$), were higher at elevated $CO_2$ than at ambient $CO_2$, while the light compensation point ($Q_{comp}$) was lower at elevated $CO_2$. In particular, the maximum photosynthetic rate ($A_{max}$) was higher at elevated $CO_2$ by 2.2-fold than at ambient $CO_2$. However, the photosynthetic $CO_2$-response parameters such as light respiration rate ($R_p$), maximum Rubisco carboxylation efficiency ($V_{cmax}$), and $CO_2$ compensation point (CCP) were less responsive to elevated $CO_2$ relative to the light-response parameters. The photochemical efficiency parameters ($F_v/F_m$, $F_v/F_o$) of PSII were not significantly affected by elevated $CO_2$, suggesting that elevated atmospheric $CO_2$ will not reduce the photosynthetic efficiency of Chinese cabbage in highland cropping. The optimal temperature for photosynthesis shifted significantly by about $2^{\circ}C$ under elevated $CO_2$. Above the optimal temperature, the photosynthetic rate (A) decreased and the dark respiration rate ($R_d$) increased as the temperature increased. These findings indicate that future increases in $CO_2$ will favor the growth of Chinese cabbage on highland cropping, and its productivity will increase due to the increase in photosynthetic affinity for light rather than $CO_2$.

• Economic and Environmental Geology
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• v.2 no.4
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• pp.23-71
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• 1969

Sediment samples were taken at about half-mile intervals from all the inajor rivers draining the St. Austell granite mass. The minus 80 mesh(B.S.S.) fraction of each sample was analysed, using semiquantitative methods, for sodium, potassium, lithium, phosphorus, nickel, chromium, tin, tungsten, arsenic copper, zinc and lead. The work was carried out with the view to gaining further information as to the geographical distribution of such different granite facies as might axist, and to investigate the geochemical dispersion of these elements with relation to mineralisation in this area. The sesults confirm Exley's suggestion that the mass consists of two major granite intrusions, the earlier undifferentiated one is joined on the west by a later differentiated intrutive. During the work grid deviation maps proved particularly useful in obtaining data concerning the nature of the granite but frequency diagrams were not particularly helpful. All the known lode areas were associated with stream sediments containing anomalously high concentrations of lode metals and it is concluded that these high concentrations are due premarily to lode material transferred to the streams in the form of tailings lost during milling operations.

• Economic and Environmental Geology
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• v.45 no.1
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• pp.1-8
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• 2012

Copper-zinc-bearing skarns of the Kasihan area developed at limestone layers in the sedimentary facies of the Late Oligocene Arjosari Formation. The skarns consist mainly of fine-grained, massive clinopyroxene-garnet, garnet, garnet-epidote, and epidote skarns. Most copper and zinc(-lead) ore mineralization occur in the clinopyroxene-garnet and garnetepidote skarn, respectively. Clinopyroxene occurs as a continuous solid solution of diopside and hedenbergite (from nearly pure diopside up to ${\approx}34$ mole percent hedenbergite), with a maximum 28.2 mole percent johannsenite component. The early and late pyroxenes of Kasihan skarns are diopsidic and salitic, respectively. They fall in the fields typical Cu- and Zn-dominated skarns, respectively. Garnet displays a relatively wide range of solid solution between grossular and andradite with up to ${\approx}2.0$ weight percent MnO. Garnet in early pyroxene-garnet skarn ranges from 49.1 to 91.5 mole percent grossular (mainly ${\geq}78$ mole % grossular). Garnets in late garnet and garnet-epidote skarns range from 2.8 to 91.4 mole percent grossular (mainly ${\geq}70$ mole % for garnet skarn). Epidote compositions indicate solid solutions of clinozoisite and pistacite varying from 65.8 to 76.2 mole percent clinozoisite. Phase equilibria indicate that skarn evolution was the result of interaction of water-rich fluids ($X_{CO_2}{\leq}0.1$) with original lithologies at ${\approx}0.5$ kb with declining temperature (early clinopyroxene-garnet and garnet skarn, ${\approx}450$ to $370^{\circ}C$; late garnet-epidote and epidote skarn, ${\approx}370$ to $300^{\circ}C$).

• Journal of the korean academy of Pediatric Dentistry
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• v.43 no.2
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• pp.166-175
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• 2016

There is no genetic activity information with the functions of dental pulp and periodontal ligament in human. The purpose of this study was to identify the gene-expression profiles of, and the molecular biological differences between periodontal ligament and dental pulp obtained from human permanent teeth. cDNA microarray analysis identified 347 genes with a fourfold or greater difference in expression level between the two tissue types 83 and 264, of which were more plentiful in periodontal ligament and dental pulp, respectively. Periodontal ligament exhibited strong expression of genes related to collagen synthesis (FAP), collagen degradation (MMP3, MMP9, and MMP13), and bone development and remodeling (SSP1, BMP3, ACP5, CTSK, and PTHLH). Pulp exhibited strong expression of genes associated with calcium ions (CALB1, SCIN, and CDH12) and the mineralization and formation of enamel and dentin (SPARC/SPOCK3, PHEX, AMBN, and DSPP). Among these genes, SPP1, SPARC/SPOCK3, AMBN, and DSPP were well known in dental research. However, the other genes are the newly found and it may help to find a good source of regenerative therapy if further study is performed.

• Journal of the korean academy of Pediatric Dentistry
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• v.40 no.3
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• pp.185-193
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• 2013

Mineral trioxide aggregate (MTA) has recently been used as a pulpotomy medicament for primary molars. The aim of this study was to evaluate and compare the proliferation and differentiation potential of dental pulp stromal cells of permanent teeth and deciduous teeth cultured on MTA-coated surface. Human dental pulp stromal cells were obtained from human permanent premolars and deciduous teeth and cultured on MTA-coated culture plates. The cells were subjected to proliferation assay and cell cycle analysis. Their differentiation potential was evaluated by analysing changes in the mRNA expressions of runt-related transcriptional factor 2 (Runx2) and alkaline phosphatase (ALP). Morphological changes of cells in direct contact with MTA were observed using scanning electron microscopy (SEM). The proliferation rates, distribution of cell cycles and mRNA expression patterns of Runx2 and ALP were similar in both types of pulpal cells. SEM observations revealed that both types changed into more dendrite-like cells. On the surface of MTA, human dental pulp stromal cells from deciduous and permanent teeth were able to both proliferate and differentiate into cells that induce mineralization. MTA is suitable as a biocompatible pulpotomy medicament for primary teeth.