• Economic and Environmental Geology
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• v.46 no.3
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• pp.207-214
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• 2013

To identify rock-magnetic properties of volcanogenic hydrothermal sulfide deposits, chimneys were obtained from the Tofua Arc in Southwest Pacific, using a remotely operated vehicle (ROV) and Grab with AV cameras (GTVs). Three different types of chimneys used in this study are a high-temperature chimney with venting fluid-temperature of about $200^{\circ}C$ (ROV01), a low-temperature chimney of about $80^{\circ}C$ (GTV01), and an inactive chimney (ROV02). Magnetic properties of ROV01 are dominated by pyrrhotite, except for the outermost that experienced severe oxidation. Concentration and grain-size of ROV01 pyrrhotite are relatively low and fine. For GTV01, both magnetic concentration and grain-size increase from interior to margin. Pyrrhotite, dominant in the core, becomes mixed with hematite in the rim of the chimney due to secondary oxidation. High concentration and large grain-size of magnetic minerals characterize the ROV02. Dominant magnetic phases are pyrrhotite, hematite and goethite. In particular, the outermost rim shows a presence of magnetite produced by magnetotactic bacterial activity. Such distinctive contrast in magnetic concentration, grain-size and mineralogy among three different types of chimney enables the rock-magnetic study to characterize an evolution of hydrothermal deposits.

• Journal of Environmental Science International
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• v.24 no.2
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• pp.197-205
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• 2015

This study was performed to identify the effect of fertilizer application and planting method on growth and yield of 'Seolhyang' strawberry during seedling raising. According to the concentration of fertilizer applied, the height of daughter plants was the highest at an EC of $0.8dS{\cdot}m^{-1}$. Leaf number and crown diameter were greatest at an EC of $0.6-0.8dS{\cdot}m^{-1}$. In the first measurement, root number was highest in non-fertilizer application, while root weight was heaviest in non-fertilizer application and EC $0.4dS{\cdot}m^{-1}$. The higher the concentration of fertilizer applied as culture media, the lower the growth rate. Thirty days after planting on the main field, plant height and number of new leaf were highest at an EC of $0.8dS{\cdot}m^{-1}$. However, no significant difference was found in leaf length and width and chlorophyll content according to fertilizer application. Marketable yield of 25 g or higher was greatest in EC $0.6dS{\cdot}m^{-1}$. In contrast, no significance was found in total marketable yield at an EC of $0.4-0.8dS{\cdot}m^{-1}$. Aconsistent pattern was exhibited in the growth of 1-5 harvesting flower clusters according to planting method. The length of leaf and flower cluster was short and chlorophyll content was low, when bed soil was removed 100% in harvesting of the first flower cluster. In all treatment, leaf length was shortened until harvesting of the second and third flower cluster, but rapidly lengthened in harvesting of the third and fourth flower clusters. Moreover, the length of flower cluster had a increasing tendency from harvesting of the third flower cluster. However, chlorophyll content was reduced continuously until harvesting of the fifth flower cluster, and was lowest in harvesting of the fourth flower cluster without removal of bed soil. Total yield was greatest in treatment of crown removal in bed soil between November and May. Late marketable yield between March and May was highest in treatment of 100% bed soil removal, followed by treatment of crown removal. Marketable yield of 25 g or higher was greatest in treatment of crown removal between December and February, while greatest in treatment of 100% bed soil removal between March and May.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.21 no.3
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• pp.139-145
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• 2011

Objectives: This investigation is purposed to evaluate the airborne asbestos concentrations in the public buildings having asbestos containing materials(ACMs) in Seoul. Methods: The Seoul Metropolitan Government carried out an asbestos survey to the city-owned public buildings to identify the level of risk exposure, classified into low, moderate and high risk. To evaluate the airborne concentration of asbestos, 11 sampling sites in ten buildings based on the survey were selected. The air samples from the eleven sites were analyzed by Phase Contrast Microscopy(PCM) and Transmission Electron Microscopy (TEM), and compared the analytical results from the both. Results: 1. The airborne fiber concentrations by PCM were less than the detection limit($7f/mm^2$) in 9(82%) out of 11 sampling sites. The highest concentration was 0.0043 f/cc, but it was below the guideline value for indoor air quality(0.01 f/cc), proposed by the Ministry of Environment, Korea. 2. In two sampling sites, having moderate risk level, the chrysotile was identified and showed it's concentrations of 0.0102 s/cc and 0.0058 s/cc, less than $5{\mu}m$ lengths. 3. The ACMs identified in the two sampling sites were a packing material(65% of chrysotile) in mechanical area and a thermal system insulation(5% of chrysotile) in a boiler room. Having more possibility of asbestos emission in the mechanical area, it would be required to set up and carry out the asbestos management plan. Conclusions: Based on the result of this study, the airborne asbestos concentrations in the public buildings with ACMs were generally lower than the guideline value for indoor air quality. There are widespread concerns about the possible health risk resulting from the presence of airborne asbestos fibers in the public buildings. Most of the previous studies about airborne asbestos analysis in Korea were performed based on PCM method that asbestos and non-asbestos fibers are counted together. In the public and commercial buildings, having ACMs, it is suggested that the asbestos be analyzed by TEM method to identify asbestos due to concerns about asbestos exposure to workers and unspecified people.

• Journal of fish pathology
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• v.4 no.2
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• pp.59-70
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• 1991

In order to investigate the effects of glutathione against ceroidosis on flounder, Paralichthys olivaceus, a serial experiment was carried out at indoor tanks in Cheju province, the southern island of R.O.Korea, from October 1 to November 4 of 1991. The choosed group of flounder for this experiment, ranged from 92 to 122g in body weight, already showed a distinct histological ceroidosis in liver, spleen, kidney about six months before this experiment. They were fed on formulated diets supplemented with glutathione of 0mg, 1mg, 2mg, 5mg, 10mg per kg of diet per day. Some flounders were fed on the decomposed diet as a control continuosuly. Two individuals fed on the experimental diets were cought at an interval 7 days for 35 days and analyzed the values of blood indexs. 1. While the values of RBC, Hb, Ht, MCHC, MCV of flounder fed on the decomposed diet and the glutathione non-supplemented diet were not changed compared with the beginning levels of experiment, those fed on the glutathione supplemented diets, showed markedly increased values from 7th day of experiment and from 21th day of experiment reached to the values of healthy flounder. 2. The variation of TP, Glu, Alp, BUN, TG, T-cho, GOT and GPT were not observed in the groups fed on the control diet and glutathione non-supplemented diet. In contrast, those values in the groups fed on the glutathione supplemented diets were markedly decreased from 7th day and become constant from 21th day. 3. The effect of glutathione supplementation with high concentration in diets showed much better improvements of symptoms concequently, compared with those of low concentration diets.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.10
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• pp.1359-1366
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• 2000

An experiment was carried out to study plasma levels of hormones and metabolites of crossbred Holstein cattle during late pregnancy (28 days pre partum), early lactation (30 days post partum), mid-lactation (120 days post partum) and late lactation (210 days post partum). Two breed types of Holstein $Friesian{\times}Red$ Sindhi (50:50 = 50%HF) and Holstein $Friesian{\times}Red$ Sindhi (87.5:12.5 = 87.5%HF) were divided into four groups of four animals each. Two groups of each breed were fed with either rice straw treated with 5% urea or pangola hay (Digitaria decumbens) as the source of roughage throughout the experiments. There were a substantial increases in the mean levels of total triiodothyronine ($T_3$), insulin and glucagon at the onset of lactation, and maintained in a high levels during lactation advance for all groups of experiments. The mean levels of prolactin and thyroxine ($T_4$) were not significantly different among groups of animals, but the plasma cortisol concentration was slightly higher in both groups of 50%HF in comparison with those of 87.5%HF animals. The mean levels of plasma growth hormone (GH) of both groups of 87.5%HF animals feeding on either hay or urea treated rice straw markedly rose in the early period of lactation and markedly reduced in mid- and late lactation. These changes were accompanied with changes of milk yield. In contrast to 50%HF animals, plasma GH levels were considerably higher in the late pregnant period than in the early period of lactation and it remained constant as its value at the early lactation throughout the experimental period. The high levels of both plasma progesterone and estradiol concentration significantly declined after parturition and remained low through lactating period. The plasma glucose level in the 50%HF animals feeding on either hay or urea treated rice straw was higher than the 87.5%HF animals in all periods of experiments. Changes in plasma FFA levels of both types of crossbred animals were depended on the endocrine status during late pregnancy and lactation. The levels of plasma FFA of 50%HF animals were significantly higher (p<0.05) than those of 87.5%HF animals during late pregnancy. Both plasma ${\beta}$-hydroxybutyrate and lactate concentrations were not affected by feeding on either hay or urea treated rice straw during late pregnancy and lactation. These data demonstrate that there were no differences in the physiological performances in the same crossbred animals fed either hay or urea treated rice straw. The 87.5%HF animal has the genetic potential for a high milk yield and homeorhetic adaptation for mammary function differed from 50%HF animals during periods of lactation. Altering lactation persistency in 87.5%HF is regulated mainly by chronically acting growth hormones through the period of lactation.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.9
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• pp.513-518
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• 2017

In this paper, the removal efficiency of THMs (Trihalomethanes) and DOC (Disolved organic carbon) was compared under different GAC (Granual activated carbon) filling methods. One method is "full filling method" in which column is fully filled with GAC at once and the other is "periodic cumulative method" in which column is partially filled with GAC (10, 20, 33 and 50% of total column volume) and added each ratio during 300 days. The effluent concentration of both THMs and DOC under full filling method was low during the initial period, however, steadily increased with operating time. In the contrast, with periodic cumulative method, it maintained (relatively) evenly during the operating period. Periodic cumulative method was more efficient for removing THMs than full filling method. However, when the ratio of chlorodibromomethane or bromoform among THMs was significantly higher than chloroform and bromodichloromethane, full filling method was more efficient than periodic cumulative method. Full filling method had benefit to total DOC removal and control of average DOC concentration in effluent. Overall, periodic cumulative method is more efficient to equalize the removal efficiency of THMs and DOC, so the more frequent refilling of column with small amount of GAC is more advantageous.

• Korean Journal of Weed Science
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• v.16 no.2
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• pp.160-170
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• 1996

Several physiological responses were investigated in plants treated with TOPE as a preliminary step to know its action site. Unlike photo-dependent diphenylethers, herbicidal activity of TOPE appeared slowly and its typical symptoms were both burning of leaf blades and abnormal division of meristem in grasses, Similarly, both leakage of cell electrolytes and the curling of cotyledon margin were also shown in cucumber(Cucumis sativus L.). Biosynthesis of chlorophyll in etiolated cucumber cotyledon was not inhibited directly by treatment of TOPE at low light intensity(5.5${\mu}$ mol $m^{-2}s^{-1}$ PAR) and protoporphyrin IX was not also accumulated. The contents of phytoene, phytofluene and ${\beta}$-carotene were abnormaly increased. Photosynthesis was inhibited only at high concentration. Mitochondrial respiration was inhibited at high concentration but rather increased significantly at 10${\mu}$M of TOPE. However, respiration inhibitors did not alleviate the two symptoms of TOPE in cucumber cotyledon. In the same experiments, using inhibitors of protein or nucleic acid biosynthesis, only one of the two symptoms was alleviated by chloramphenicol and cycloheximide. In contrast, both symptoms were alleviated by actinomycin-D and hydroxyurea, suggesting that nucleic acid metabolism might be preferentially related to the mode of action of TOPE. DNA, RNA and protein contents were accumulated in both cucumber cotyledon and rice (Oryza sativa L.) routs treated with TOPE, and the DNA of them was increased at first. Thus, it is conjectured that TOPE increase nucleic acid metabolism directly or indirectly, and then disturb various metabolic pathways causing abnormal physiological and morphological effects followed by final death.

• Atmosphere
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• v.27 no.1
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• pp.41-54
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• 2017

Organic carbon (OC) and elemental carbon (EC) in $PM_{2.5}$ were measured using Sunset OC/EC Field Analyzer at Seoul Hwangsa Monitoring Center from March to April, 2016. The mean concentrations of OC and EC during the entire period were $4.4{\pm}2.0{\mu}gC\;m^{-3}$ and $1.4{\pm}0.6{\mu}gC\;m^{-3}$, respectively. OC/EC ratio was $3.4{\pm}1.0$. The average concentrations of $PM_{10}$ and $PM_{2.5}$ were $57.4{\pm}25.9$ and $39.7{\pm}19.8{\mu}g\;m^{-3}$, respectively, which were detected by an optical particle counter. The OC and EC peaks were observed in the morning, which were impacted by vehicle emission, however, their diurnal variations were not noticeable. This is determined to be contributed by the long-range transported OC or secondary formation via photochemical reaction by volatile organic compounds at afternoon. A conditional probability function (CPF) model was used to identify the local source of pollution. High concentrations of $PM_{10}$ and $PM_{2.5}$ were observed from the westerly wind, regardless of wind speed. When wind velocity was high, a mixing plume of dust and pollution during long-range transport from China in spring was observed. In contrast, pollution in low wind velocity was from local source, regardless of direction. To know the effect of long-range transport on pollution, a concentration weighted trajectory (CWT) model was analyzed based on a potential source contribution function (PSCF) model in which 75 percentiles high concentration was picked out for CWT analysis. $PM_{10}$, $PM_{2.5}$, OC, and EC were dominantly contributed from China in spring, and EC results were similar in both PSCF and CWT. In conclusion, Seoul air quality in spring was mainly affected by a mixture of local pollution and anthropogenic pollutants originated in China than the Asian dust.

• Reproductive and Developmental Biology
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• v.41 no.1
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• pp.1-6
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• 2017

In all mammalian species, progesterone is essential to both the preparation for, and maintenance of, pregnancy. The $20{\alpha}$-hydroxysteroid dehydrogenase ($20{\alpha}$-HSD) enzyme predominantly converts progesterone into its biologically inactive form $20{\alpha}$-hydroxyprogesterone, thereby regulating its activity. Thus, to directly assess sexual maturation in the MediKinetics $micropig^{(R)}$, we analyzed the concentration of the steroid hormones progesterone and estradiol during the estrous cycle. Our results show that the progesterone level exhibited by the analyzed $micorpig^{(R)}$ was low at the beginning of the estrous cycle, and then abruptly increased to $30.32{\pm}10.0ng/mL$ and $46.37{\pm}11.0ng/mL$ by days 9 and 11 of the cycle, respectively. It reached the highest level $55.87{\pm}3.5ng/mL$ on day 13 of the estrous cycle, before decreasing to $46.58{\pm}13.1ng/mL$ and $10.0{\pm}7.6ng/mL$ by days 15 and 17 of the cycle, respectively. In contrast, the estradiol level was shown to be highest ($27.13{\pm}11.2ng/mL$) at the initiation of the estrous cycle, after which point it decreased to $13.29{\pm}6.5ng/mL$ and $10.94{\pm}5.9ng/mL$ by days 4 and 5 of the estrous cycle, respectively. By day 17 of the estrous cycle, the estradiol level decreased to $4.13{\pm}7.6ng/mL$. We anticipate that these results will provide useful information to enable the study of human ovulation and reproductive physiology using the MediKinetics $micoripig^{(R)}$ as a model system. We recommend further investigation to elucidate the functional mechanisms underlying the regulation of sexual maturation in the MediKinetics $micropig^{(R)}$.

• Journal of the Korean Ceramic Society
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• v.38 no.12
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• pp.1115-1122
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• 2001

The tendency of the miximum brightness of $Y_2$O$_3$:Eu phosphor with various activator concentration, by different surface treatment methods as well as different exciting energies were investigated. The surface treatment methods were the adsorption method used $\alpha$-Fe$_2$O$_3$powder prepared emulsion-drying process and the precipitation method used FeSO$_4$/ethanol. Eu concentration of maximum brightness of $Y_2$O$_3$:Eu phosphor prepared by solid-solid state was changed with various exciting energies. The concentrations were 0.02 mol at VUV(147 nm) as well as 400 V and 0.03 mol at 5 kV. The phosphor treated both by adsorption method and precipitation method showed decreasing luminescent intensity with increasing amount of $\alpha$-Fe$_2$O$_3$, and the methods are chosen by exciting energy. Adsorption method was effective in a low voltage and VUV(147nm) region, and precipitation method was effective in the high voltage region.