• Radiation Oncology Journal
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• v.15 no.1
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• pp.37-47
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• 1997

Purpose : To investigate ultrastructural changes of the mouse lung induced by whole lung gamma irradiation and to evaluate the effect of prophylactic administration of steroid against acute lung injury. Materials and Methods :. One hundred and twenty ICR mice were used and whole lung was irradiated with telecobalt machine. Whole lung doses were 8 and 12Gy, and 10mg of methyl prednisolone was administrated intraperitoneally for two and four weeks. At the end of the observation period, mice were sacrificed by cervical dislocation. The lungs were removed and fixed inflated. Histopathological examination of acute radiation injuries were Performed by light microscopic and transmission electron microscopic examination. Results : Control group with BGy is characterized by damage to the type I Pneumocyte and the endothelial cell of the capillary. edema of alveolar wall and interstitium. and fibroblast proliferation. Control group with 120y is characterized by more severe degree of type 1 pneumocyte damage and more prominant inflammatory cell infiltration. Destructed cell debris within the alveolar space were also noted After steroid administration, 8Gy experimental group showed decreased degree of inflammatory reactions but fibroblast proliferation and basal lamina damages were unchanged. Experimental group with 12Gy showed lesser degree of inflammatory reactions similar to changes of 8Gy experimental group. Conclusion : These studies suggest that the degree of interstitial edema and inflammatory changes were related to radiation dose but Proliferation of the fibroblast and structural changes of basal lamina were not related to radialion dose. Experimental administration of steroid for 2 to 4 weeks after whole lung irradiation suggest that steroid can suppress alveolar and endothelial damages induced by whole lung irradiation but Proliferation of the fibroblast and structural changes of basal lamina were not related to administration of steroid.

• Radiation Oncology Journal
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• v.15 no.3
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• pp.197-206
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• 1997

Purpose : Phospholipase D (PLD) catalyzes the hydrolysis of phosphatidylcholine to phosphatidic acid (PA) and choline. Recently, PLD has been drawing much attentions and considered to be associated with cancer Process since it is involved in cellular signal transduction. In this experiment, oleate-PLD activities were measured in various tissues of the living rats after whole body irradiation. Materials and Methods : The reaction mixture for the PLD assay contained $0.1\;\muCi\;1,2-di[1-^{14}C]palmitoyl$ phosphatidylcholine 0.5mM phosphatidylcholine, 5mM sodium oleate, $0.2\%$ taurodeoxycholate, 50mM HEPES buffer(pH 6.5), 10mM $CaCl_2$, and 25mM KF. phosphatidic acid, the reaction product, was separated by TLC and its radioactivity was measured with a scintillation counter. The whole body irradiation was given to the female Wistar rats via Cobalt 60 Teletherapy with field size of 10cmx loom and an exposure of 2.7Gy per minute to the total doses of 10Gy and 25Gy. Results : Among the tissues examined, PLD activity in lung was the highest one and was followed by kidney, skeletal muscle, brain, spleen, bone marrow, thymus, and liver. Upon irradiation, alteration of PLD activity was observed in thymus, spleen, lung, and bone marrow. Especially PLD activities of the spleen and thymus revealed the highest sensitivity toward $\gamma-rar$ with more than two times amplification in their activities In contrast, the PLD activity of bone marrow appears to be reduced to nearly $30\%$. Irradiation effect was hardly detected in liver which showed the lowest PLD activity. Conclusion : The PLD activities affected most sensitively by the whole-body irradiation seem to be associated with organs involved in immunity and hematopoiesis. This observation s1ron91y indicates that the PLD is closely related to the physiological function of these organs, Furthermore, radiation stress could offer an important means to explore the phenomena covering from cell Proliferation to cell death on these organs.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.4
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• pp.384-398
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• 2015

In this paper, the high-resolution Weather Research and Forecasting/Noah-MultiParameterization (WRF/Noah-MP) modeling system is configured for the Cheongmicheon Farmland site in Korea (CFK), and its performance in land and atmospheric simulation is evaluated using the observed data at CFK during the 2014 special observation period (21 August-10 September). In order to explore the usefulness of turning on Noah-MP dynamic vegetation in midterm simulations of surface and atmospheric variables, two numerical experiments are conducted without dynamic vegetation and with dynamic vegetation (referred to as CTL and DVG experiments, respectively). The main results are as following. 1) CTL showed a tendency of overestimating daytime net shortwave radiation, thereby surface heat fluxes and Bowen ratio. The CTL experiment showed reasonable magnitudes and timing of air temperature at 2 m and 10 m; especially the small error in simulating minimum air temperature showed high potential for predicting frost and leaf wetness duration. The CTL experiment overestimated 10-m wind and precipitation, but the beginning and ending time of precipitation were well captured. 2) When the dynamic vegetation was turned on, the WRF/Noah-MP system showed more realistic values of leaf area index (LAI), net shortwave radiation, surface heat fluxes, Bowen ratio, air temperature, wind and precipitation. The DVG experiment, where LAI is a prognostic variable, produced larger LAI than CTL, and the larger LAI showed better agreement with the observed. The simulated Bowen ratio got closer to the observed ratio, indicating reasonable surface energy partition. The DVG experiment showed patterns similar to CTL, with differences for maximum air temperature. Both experiments showed faster rising of 10-m air temperature during the morning growth hours, presumably due to the rapid growth of daytime mixed layers in the Yonsei University (YSU) boundary layer scheme. The DVG experiment decreased errors in simulating 10-m wind and precipitation. 3) As horizontal resolution increases, the models did not show practical improvement in simulation performance for surface fluxes, air temperature, wind and precipitation, and required three-dimensional observation for more agricultural land spots as well as consistency in model topography and land cover data.

• Journal of Radiation Protection and Research
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• v.36 no.2
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• pp.93-98
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• 2011

We induced the activation of melanocytes in the epidermis of C57BL/6 mice by ultraviolet-B (UV-B) irradiation, and observed the effect of an herbal preparation (HemoHIM, HH) on the formation, and decrease of UV-B-induced epidermal melanocytes. C57BL/6 mice were irradiated by UV-B $80\;mJ{\cdot}cm^{-2}$ ($0.5\;mW{\cdot}sec^{-1}$) daily for 7 days, and HH was intraperitoneally, orally or topically applied pre- or post-irradiation. For the estimation of change of epidermal melanocytes, light microscopic observation with dihydroxyphenylalanine (DOPA) stain was performed. Split epidermal sheets prepared from the ear of untreated mice exhibited 13~15 melanocytes${\cdot}mm^{-2}$, and one week after UV irradiation, the applied areas showed an increased number of strongly DOPA-positive melanocytes with stout dendrites. But intraperitoneal, oral or topical treatment with HH before each irradiation interrupted UV-B-induced pigmentation and resulted in a marked reduction in the number of epidermal melanocytes as compared to the number found in UV-B-irradiated, untreated control skin. The number and size of DOPA-positive epidermal melanocytes were also significantly decreased in intraperitoneally injected or topically applicated group after irradiation with HH at 3rd and 6th weeks after irradiation. The present study suggests the HH as inhibitor of UV-B-induced pigmentation, and depigmenting agent.

• Journal of Environmental Science International
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• v.19 no.11
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• pp.1397-1405
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• 2010

Mass mortalities of cultivated organisms have occurred frequently in Korean coastal waters causing enormous losses to cultivating industry. The preventive measures require continuous observation of farm environment and real-time provision of data. However, line hanging aquaculture farm are generally located far from monitoring buoys and has limitations on installation of heavy equipments. Substituting battery pack for solar panels and miniaturizing size of buoy, newly developed system can be attached to long line hanging aquaculture farm. This system could deliver measured data to users in real-time and contribute to damage mitigation and prevention from mass mortalities as well as finding their causes. The system was installed off Gijang and Yeongdeck in Korea, measuring and transmitting seawater temperature at the sea surface every 30 minutes. Short term variation of seawater temperature, less than one day, in Gijang from June to July 2009 corresponded tidal period of about 12 hours and long term variation seemed to be caused by cold water southeast coast of Korea, particularly northeast of Gijang. Seawater temperature differences between Gijang station and the other station that is about 500 m away from Gijang station were $1^{\circ}C$ on average. This fact indicates that it is need to be pay attention to use substitute data even if it is close to the station. Daily range of seawater temperature, one of crucial information to aquaculture, can be obtained from this system because temperature were measured every 30 minutes. Averages of daily range of temperature off Gijang and Yeongdeok during each observation periods were about $2.9^{\circ}C$ and $4.7^{\circ}C$ respectively. Dominant period of seawater temperature variation off Yeongdeok was one day with the lowest peak at 5 a.m. and the highest one at 5 p.m. generally, resulting from solar radiation.

• Journal of Environmental Science International
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• v.17 no.9
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• pp.1053-1068
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• 2008

This study aims to produce fundamental database for Environment Impact Assessment by monitoring vertical structure of the atmosphere due to the mountain valley wind in spring season. For this, we observed surface and upper meteorological elements in Sangin-dong, Daegu using the rawinsonde and automatic weather system(AWS). In Sangin-dong, the weather condition was largely affected by mountains when compared to city center. The air temperature was low during the night time and day break, and similar to that of city center during the day time. Relative humidity also showed similar trend; high during the night time and day break and similar to that of city center during the day time. Solar radiation was higher than the city, and the daily maximum temperature was observed later than the city. The synoptic wind during the measurement period was west wind. But during the day time, the west wind was joined by the prevailing wind to become stronger than the night time. During the night time and daybreak, the impact of mountain wind lowered the overall temperature, showing strong geographical influence. The vertical structure of the atmosphere in Dalbi valley, Sangin-dong had a sharp change in air temperature, relative humidity, potential temperature and equivalent potential temperature when measured at the upper part of the mixing layer height. The mixing depth was formed at maximum 1896m above the ground, and in the night time, the inversion layer was formed by radiational cooling and cold mountain wind.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.3
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• pp.167-175
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• 2019

Water color analysis allows non-destructive estimation of abundance of optically active water constituents in the water body. Recently, there have been increasing needs for light-weighted multispectral cameras that can be integrated with low altitude unmanned platforms such as drones, autonomous vehicles, and heli-kites, for the water color analysis by spectroradiometers. This study performs the preprocessing of the Micasense Rededge-M camera which recently receives a growing attention from the earth observation community for its handiness and applicability for local environment monitoring, and investigates the applicability of Rededge-M data for water color analysis. The Vignette correction and the band alignment were conducted for the radiometric image data from Rededge-M, and the sky, water, and solar radiation essential for the water color analysis, and the resultant remote sensing reflectance were validated with an independent hyperspectral instrument, TriOS RAMSES. The experiment shows that Rededge-M generally satisfies the basic performance criteria for water color analysis, although noticeable differences are observed in the blue (475 nm) and the near-infrared (840 nm) band compared with RAMSES.

• Journal of Environmental Health Sciences
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• v.33 no.2 s.95
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• pp.123-131
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• 2007

Many environmental contaminants including several metals, polycyclic aromatic hydrocarbons, and pharmaceuticals, have been identified to be phototoxic in the water environment. Concerns regarding photo-enhancement of toxicity of several environmental contaminants have been increasing because of the increased level of ultraviolet irradiation on the earth surface. However, there exist arguments that there might be certain defense mechanisms taking place in the aquatic ecosystem, which may include behavioral characteristics or genetic acclimation. This study was conducted to understand the potential responses of aquatic receptors to several phototoxic metals in the real environment, where long-term acclimation of such organisms to low dose UV-B may take place. For this purpose, water flea Daphnia magna was acclimated to environmentally relevant dose of UV-B (12 to $18uW/cm^2$) for >11 generations. The differences in developmental and life history characteristics, and toxicity responses were evaluated. Acclimation did not affect the daphnids' growth, longevity, and reproduction characteristics such as time to first brood, and brood size: After 21 d, survival of D. magna was not influenced by UV-B acclimation. When the number of young per female was compared. the daphnids acclimated for 11 generations tend to produce less number of neonates than the un-acclimated individuals but with no statistical significance (p>0.05). Four metals that were reported to be phototoxic elsewhere were employed in this evaluation, that include As, Cd. Cu, and Ni. UV-B level being applied in acclimation did increase the toxicity of Cd and Cu, significantly (p<0.05). However, the toxicities of As and Ni were not affected by irradiation of UV-B. Phototoxic responses were evaluated between the acclimated and the un-acclimated daphnids. For Cu, UV-B acclimation led to reduction of the photo-induced toxicity $(p\approx0.1)$ in daphnids. Non-acclimated Daphnia were affected by 50% at 4.18 ug/l Cu. but UV-B acclimated individuals exhibited $EC_{50}$ of 5.89 ug/l. With Cd, UV-B acclimation appeared to increase phototoxicity (p>0.05). With As and Ni, UV-B acclimation did not influence photo-induced toxicity. This observation may be in part explained by the type of reactive oxygen species that were generated by each metal. Similar to UV-B light, Cu is known to generate superoxide anion by acting as redox cycling toxicant. This is one of the first studies that employed_laboratory based UV-B acclimated test species for photoenhanced toxicity evaluation.

• Korean Journal of Agricultural and Forest Meteorology
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• v.4 no.2
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• pp.95-102
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• 2002

Spatial interpolation has become a common procedure in converting temperature forecasts and observations at irregular points for use in regional scale ecosystem modeling and the model based decision support systems for resource management. Neglection of terrain effects in most spatial interpolations for short term temperatures may cause erroneous results in mountainous regions, where the observation network hardly covers full features of the complicated terrain. A spatial interpolation model for daytime hourly temperature was formulated based on error analysis of unsampled site with respect to the site topography. The model has a solar irradiance correction scheme in addition to the common backbone of the lapse rate - corrected inverse distance weighting. The solar irradiance scheme calculates the direct, diffuse and reflected components of shortwave radiation over any surfaces based on the sun-slope geometry and compares the sum with that over a reference surface. The deviation from the reference radiation is used to calculate the temperature correction term by an empirical conversion formula between the solar energy and the air temperature on any sloped surfaces at an hourly time scale, which can be prepared seasonally for each land cover type. When this model was applied to a 14 km by 22 km mountainous region at a 10 m horizontal resolution, the estimated hourly temperature surfaces showed a better agreement with the observed distribution than those by a conventional method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.9
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• pp.914-923
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• 2009

Helix antennas have been widely applied to satellite TT&C, data communication and GPS receiver systems onboard military, remote sensing and communication purpose satellites. The helix antennas are known to be convenient to control impedance and radiation coverage characteristics with a maximum directivity in satellite z-axis. Waveguide horn is commonly used for radar system that needs ultra-wideband pulse for exploration ground radar and electromagnetic disability measurement etc. It has high efficiency and low reflection characteristics provided by the low-profile shape and suppressed radiation distortion. In this paper, a waveguide horn structure incorporated with helix antenna design is proposed for satellite applications that require ultra-wideband pulse radar and high rate RF data communication link to ground station over wide coverage area. The main design concern is to synthesize variable beam forming pattern based on modified horn-helix combination helicone structure such that multi-mission antenna is implemented applicable for TT&C, earth observation, high data rate transmission. Waveguide horn helps to reduce the overall antenna structure size by introduction fold type reflector connected to the tapered helix antenna. The next generation KOMPSAT satellite currently under development requires high-performance precision attitude control system. We present an initial design of a hybrid hern-helix antenna structure suitable for efficient RF communication module design of multi-purpose satellite systems.