• Journal of Radiation Protection and Research
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• v.22 no.1
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• pp.35-46
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• 1997

A simple and precise method of $^{14}C$ was developed to analyze $^{14}C$ in the environment samples using a commercially available $^{14}CO_2$ absorbent and a liquid scintillation counter. An air sampler and a combustion system were developed to collect HTO and $^{14}CO_2$ in the air and the biological samples simultaneously. The collection yield of $^{14}CO_2$ by the air sampler was in the range of 73-89% . The yield of the combustion system was 97%. In preparing samples for counting, the optimum ratio of $CO_2$ absorbent to the scintillator for mixing was 1:1. No variation of the specific activity of $^{14}C$ in the counting sample was observed up to 70 days after preparation of the samples. The detection limit for$^{14}C$ was 0.025 Bq/gC, which is the level applicable to the natural level of $^{14}C$. The analytical result of $^{14}C$ obtained by the present method were within ${\pm}6%$ of the relative error from the one by the benzene synthesis. The specific activity of $^{14}C$ in the air collected at Taejon during the period of October 1996 ranged from 0.26 to 0.27 Bq/gC. The specific activity of $^{14}C$ in the air collected at 1km from the Wolsong nuclear power plant a 679 MWe PHWR, was $0.54{\pm}0.03$ Bq/gC. The ranges of specific activities of $^{14}C$ in the pine needles and the vegetations from the areas around the Wolsong nuclear power plant were 0.56-0.67 Bq/gC and 0.23-1.41 Bq/gC, respectively.

• Journal of the Korean earth science society
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• v.37 no.7
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• pp.420-433
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• 2016

The purpose of this study is to improve the calibration matrixes of 2-D and 3-D convective rainfall rates (CRR) using the brightness temperature of the infrared $10.8{\mu}m$ channel (IR), the difference of brightness temperatures between infrared $10.8{\mu}m$ and vapor $6.7{\mu}m$ channels (IR-WV), and the normalized reflectance of the visible channel (VIS) from the COMS satellite and rainfall rate from the weather radar for the period of 75 rainy days from April 22, 2011 to October 22, 2011 in Korea. Especially, the rainfall rate data of the weather radar are used to validate the new 2-D and 3-DCRR calibration matrixes suitable for the Korean peninsula for the period of 24 rainy days in 2011. The 2D and 3D calibration matrixes provide the basic and maximum CRR values ($mm\;h^{-1}$) by multiplying the rain probability matrix, which is calculated by using the number of rainy and no-rainy pixels with associated 2-D (IR, IR-WV) and 3-D (IR, IR-WV, VIS) matrixes, by the mean and maximum rainfall rate matrixes, respectively, which is calculated by dividing the accumulated rainfall rate by the number of rainy pixels and by the product of the maximum rain rate for the calibration period by the number of rain occurrences. Finally, new 2-D and 3-D CRR calibration matrixes are obtained experimentally from the regression analysis of both basic and maximum rainfall rate matrixes. As a result, an area of rainfall rate more than 10 mm/h is magnified in the new ones as well as CRR is shown in lower class ranges in matrixes between IR brightness temperature and IR-WV brightness temperature difference than the existing ones. Accuracy and categorical statistics are computed for the data of CRR events occurred during the given period. The mean error (ME), mean absolute error (MAE), and root mean squire error (RMSE) in new 2-D and 3-D CRR calibrations led to smaller than in the existing ones, where false alarm ratio had decreased, probability of detection had increased a bit, and critical success index scores had improved. To take into account the strong rainfall rate in the weather events such as thunderstorms and typhoon, a moisture correction factor is corrected. This factor is defined as the product of the total precipitable waterby the relative humidity (PW RH), a mean value between surface and 500 hPa level, obtained from a numerical model or the COMS retrieval data. In this study, when the IR cloud top brightness temperature is lower than 210 K and the relative humidity is greater than 40%, the moisture correction factor is empirically scaled from 1.0 to 2.0 basing on PW RH values. Consequently, in applying to this factor in new 2D and 2D CRR calibrations, the ME, MAE, and RMSE are smaller than the new ones.

• Pediatric Infection and Vaccine
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• v.4 no.1
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• pp.97-105
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• 1997

Purpose : Aseptic meningitis mainly caused by enterovirus is common in pediatric population especially during summer & fall. Most of pediatric patients restore their health without any complications with proper management. Between May to August of 1996, Masan and surrounding areas of the Kyoungsangnamdo were epidemic areas for the aseptic meningitis. The purpose of this study was to determine causative virus and describe correlation between disease and clinical symptoms in aseptic meningitis patients and those with fever and characteristic rashes without apparent meningitis symptoms. Methods : Between May to August, 1996, 57 patients with high fever and characteristic feature of rashes were reviewed. From 22 cerebrospinal fluid & 57 stool obtained specimens, viral culture and detection of enterovirus RNA were conducted. Collected specimens were kept in $-30^{\circ}C$ environment until sending of specimens to labortory. The virus identified through indirect immunofluorescence. RT-PCR method was used to identify enterovirus RNA in cerebralspinal fluid. Results : 1) One hundred fifty five pediatric patients with viral infection required hospitalization. Disease occurred higher rate in male than female with ratio of 1.94:1. Examined patients' age ranged from 15days old to 15years old. But most of patients(74.8%) were under age of 5years old. The time of occurrence was between May to August of 1996. 2) All patients had high fever and physical symptoms in those patients include headache, vomiting, abdominal pain, diarrhea, and rashes. The rashes observed mainly in patients under age of 4 years and were predominantly commom patients under age of 18 months olds)<0.001). 3) Between sampled patients and non-sampled patients, clinical course was similar. Echovirus type 9 was cultivated in 41 out of 57 cases of collected stool specimens. RT-PCR that used on CSF showed positive results in 10 out of 22 cases. Three cases of positive cultivated of positive results in RT-PCR were echovirus type 9. Conclusions : Echovirus type 9 was thought to be the causative agent of aseptic meningitis that was prevalent throughout mid areas of Kyoungsangnamdo from May to August, 1996. Additionally causative agent that responsible for high fever with rashes without meningitis symptoms also thought to be the same echovirus type 9.

• Pediatric Infection and Vaccine
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• v.23 no.1
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• pp.46-53
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• 2016

Purpose: Enterovirus (EV) infection in children can manifest various diseases from asymptomatic infection to nonspecific febrile illness, hand-foot-mouth disease, and aseptic meningitis. This study was aimed to investigate epidemiology and clinical significance of various genotypes of EV infections in pediatric inpatient. Methods: We collected the stool samples from the admitted pediatric patients in Inha University Hospital from March 2014 to March 2015. EV detection and genotype identification were performed by real-time RT-PCR and semi-nested RT-PCR. Phylogenetic trees were constructed by neighbor joining method. Results: A total of 400 samples were collected during study period and 112 patients (28%) were diagnosed with EV infections. The mean age of EV positive patients was 2.66 years (0.1-14) and sex ratio was 1.73:1. Genetic sequences of EVs were identified; coxsackievirus B5 (17, 15.2%), coxsackievirus A16 (13, 11.6%), enterovirus 71 (10, 8.9%), and coxsackievirus A2 (9, 8.0%). Nonspecific febrile illness (96, 86%) was the most common clinical manifestation and the duration of fever was 0-11 days (mean 3.1 days). Rash (44, 39%) and meningitis (43, 38%) were followed. Patients who were attending daycare center or had siblings accounted for 82.1%. Phylogenetic relationship tree revealed 6 distinct genogroups among 56 types of EVs. Conclusions: This study is the report of epidemiology, serotype distribution and clinical manifestations of children with EV infection in Incheon. This data will be helpful for further study about the epidemiology of EV infection in Korea.

• Journal of Sericultural and Entomological Science
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• v.29 no.2
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• pp.31-37
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• 1987

Mulberry leaf sprayed on at the various concentrations of cadmium (Cd) was fed on the just molted fifth instar through the 6th day of the fifth instar and content of cadmium and zinc in the feces, organs and tissues involved were analyzed by spectrophotometer. Along with the effect of those heavy metals on development of the relevant organs and tissues sexwise. 1. The residual content of cadmium on mulberry leaf was about 50% of the total cadmium and the weight of feces disposed from the cadmium fed larvae was less than the control. There was distinctive differences in female-wise disposal of feces between cadmium treatment and control ; cadmium treatment female larvae disposed less feces than female of control. 2. Fourteen percent of the total dry weight of the anterior plus the middle silkgland and of the posterior silkgland in cadmium 100ppm treatment was decreased in female but only 9% of the anterior plus middle silkgland in male was made, showing no decrease the weight of the posterior silkgland in male. 3. Decrease of the dry weight of the silkgland, fat body and hindgut was made in cadmium 100ppm treatment and contrarily the weight of midgut and malphihian tube were increased. The total larval weight of the female and male were decreasd in cadmium 100ppm treatment and the decreasing ratio was higher in famale. 4. There wasa no detection of cadmium in all of the organs and tissues of the control and in those of the cadmium treatment the high residual content was in order of the midgut, hindgut, malphighian tube and head. A slight accumulation of cadmium was shown in fat body and silkgland. 5. Cadmium accumulation in the midgut was higher than in female but in the fat body, malphighian tube, trachea and integument was contrarily high in the female than male. 6. The total zinc content of the larvae was below 60ppm in the control and 80ppm in cadmium 100ppm treantment. The increase of zinc content in cadmium treatment was made on silkgland, malphigian tube and midgut but contrarily the decrease of zinc content in fat body was resulted. 7. In cadmium treatment, much more cadmium accumulation took place in the female and zinc accumulation was made much more in the male.

• Korean Journal of Poultry Science
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• v.18 no.3
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• pp.183-196
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• 1991

In order to establish ELISA method to detect antibody against IBV various factors involved were examined. Antigen was prepared from Massachusetts type IBV which is known to be one of serotypes distributed most widely. The virus was grown in embryonated SPF chicken eggs. Allantoic fluid harvested was processed to ultracentrifugation and sucrose density gradient centrifugation to produce a purified antigen The antisera selected from the field samples based on hemagglutination inhibition test were used as the standard positive and negative sera for this study and the results obtained were summarized as follows. 1 , It was found that ELISA test was satisfactory when the purified antigen was coated on the plate in the amount of about 40ng protein per well. In case of the phospholipase treated hemagglutinating antigen it gave satisfactory results when the each well wns coated with 1.2 to 2.5 hemagglutinating unit which was equivalent to 40 to 90ng of protein. 2. There was no significant difference in the ratio of optical density of positive to that of negative serum whether the coated antigen was held for 1 hour at 37$^{\circ}C$ or it was held overnight at 4$^{\circ}C$. The coated antigen could be kept in dried state without change of antigenecity for at least one month of experimental period at 4$^{\circ}C$. 3. There was a big variation in the optical density and P/N values depending on the maker of the plates and on the plate of the same maker. 4. It was found that background optical density was negligible when serum was diluted more than 1：50 and serum dilution of 1：100 appeared to be appropriate as a routine test dilution to screen the antibody. 5. Optical density was fairly constant 15 minutes afterward from the time substrate was treated and during the 4 hours after stopper was treated. 6. There was a low correlation(r＝0.42) between ELISA and HI test. However, when 74serum samples were tested for the IBV antibody, 98.7% were found to be positive by both tests in which titers of 2$^{6}$ or more by HI test and P/N values of 1.4 or more by ELISA were considered to be positive, 7 Day-old IBV vaccinated chickens shows a similar antibody decay and rising pattern until 8 weeks of age by the two tests, ELISA and HI.

• Korean Journal of Remote Sensing
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• v.34 no.2_1
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• pp.267-282
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• 2018

Despite the continuous development of phenology detection studies using satellite imagery, verification through comparison with the field observed data is insufficient. Especially, in the case of Korean forests patching in various forms, it is difficult to estimate the start of season (SOS) by using only satellite images due to resolution difference. To improve the accuracy of vegetation phenology estimation, this study reconstructed the large scaled forest type map (1:5,000) with MODIS pixel resolution and produced time series vegetation phenology curves from Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) derived from MODIS images. Based on the field observed data, extraction methods for the vegetation indices and SOS for Korean forests were compared and evaluated. We also analyzed the correlation between the composition ratio of forest types in each pixel and phenology extraction from the vegetation indices. When we compared NDVI and EVI with the field observed SOS data from the Korea National Arboretum, EVI was more accurate for Korean forests, and the first derivative was most suitable for extracting SOS in the phenology curve from the vegetation index. When the eight pixels neighboring the pixels of 7 broadleaved trees with field SOS data (center pixel) were compared to field SOS, the forest types of the best pixels with the highest correlation with the field data were deciduous forest by 67.9%, coniferous forest by 14.3%, and mixed forest by 7.7%, and the mean coefficient of determination ($R^2$) was 0.64. The average national SOS extracted from MODIS EVI were DOY 112.9 in 2014 at the earliest and DOY 129.1 in 2010 at the latest, which is about 0.16 days faster since 2003. In future research, it is necessary to expand the analysis of deciduous and mixed forests' SOS into the extraction of coniferous forest's SOS in order to understand the various climate and geomorphic factors. As such, comprehensive study should be carried out considering the diversity of forest ecosystems in Korea.

• Journal of the Korean Society of Radiology
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• v.12 no.3
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• pp.403-407
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• 2018

Currently, the highest cancer death rate in Korea is lung cancer, which is a typical cancer that is difficult to detect early. Low-dose chest CT is being used for early detection, which has a greater lung cancer diagnosis rate of about three times than regular chest x-ray images. However, low-dose chest CT not only significantly reduces image resolution but also has a weak signal and is sensitive to noise. Also, air filled lungs are low-density organs and the presence of noise can significantly affect early diagnosis of cancer. This study used Visual C++ to set a circle inside a large circle with a density of 2.0, with a density of 1.0, which is the density of water, in which five small circle of mathematics have different densities. Gaussian noise was generated by 1%, 2%, 3%, and 4% respectively to determine the effect of noise on the mean value, the standard deviation value, and the relative noise ratio(SNR). In areas where the density difference between the large and small circles was greatest in the event of 1 % noise, the SNR in the area with the greatest variation in noise was 4.669, and in areas with the lowest density difference, the SNR was 1.183. In addition, the SNR values can be seen to be high if the same results are obtained for both positive and negative densities. Quality was also clearly visible when the density difference was large, and if the noise level was increased, the SNR was reduced to significantly affect the noise. Low-density organs or organs in areas of similar density to cancers, will have significant noise effects, and the effects of density differences on the probability of noise will affect diagnosis.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.3
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• pp.174-182
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• 2011

The present study evaluated the major lead sources in a steel metallurgy industrialized city by measuring lead isotopes/lead concentrations of ambient air and potential sources in an industrial area and residential areas according to relative distance. The quality control program obtained during the measurement procedure for lead isotopes and concentrations exhibited $0.5ng/m^3$ for method detection limit, more than 90% for recoveries of standard particulate matters, and lower than 0.2% for reproducibility errors of four lead isotopes ($^{204}Pb$, $^{206}Pb$, $^{207}Pb$, $^{208}Pb$). For all three lead isotope ratios ($^{206}Pb/^{204}Pb$, $^{207}Pb/^{206}Pb$, $^{208}Pb/^{206}Pb$), the ratios were obtained in the industrial area were closer to nearby residential area than those of a residential area far away from the industrial area, thereby suggesting that lead sources were more similar each other in the industrial and nearby residential area. Furthermore, for both summer and winter seasons ambient lead concentrations were more than four times higher in the industrial area than in the residential areas and in turn, they were higher in the nearby residential area compared with the far-away residential area. As a result, it was suggested that lead emitted from the industrial area would influence more the ambient lead in the nearby residential area than the far-away residential area. Both slag and traffic emissions are likely to be major lead sources in the industrial and nearby residential areas, since their three lead isotope ratios ($^{206}Pb/^{204}Pb$, $^{207}Pb/^{206}Pb$, $^{208}Pb/^{206}Pb$) were similar to the ratios obtained from ambient air of these two areas. In addition, the lead isotope ratios revealed different pattern between seasons, and the ambient lead concentrations were higher for winter than for summer.

• Journal of Food Hygiene and Safety
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• v.32 no.1
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• pp.42-49
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• 2017

The aim of this study was to determine total mercury and methyl mercury level in fishes (Deep-sea Fish, Tuna, Billfish) and fishery products. A total of 101 fishes and 44 fishery products samples collected from commercial market in Gyeonggi-do. Total mercury were analysed by mercury analyzer and methyl mercury were analyzed by gas chromatography with electron capture detector. In the fishes, total mercury was detected in all samples and methylmercury was detected in 92 samples of them. The detection rate of methylmercury was 91.1% in fishes. The mean concentration (mg/kg) of total mercury and methylmercury were $1.968{\pm}0.505/0.496{\pm}0.057$ for Billfish, $0.665{\pm}0.091/0.252{\pm}0.033$ for Deep-sea Fish and $0.577{\pm}0.085/0.218{\pm}0.025$ for Tuna, respectively. The Swordfish contains the highest level of total mercury (1.968 mg/kg) and methylmercury (0.496 mg/kg). In Mabled rockfish, the ratio of methylmercury's contents about total mercury's contents was the highest as 66.5%. In case of fishery products, frozens made of 100% of raw material contained the highest level of total mercury and methyl mercury. The weekly intake of total mercury and methylmercury was calculated in 4.72% and 5.24% of Provisional Tolerable Weekly Intake (PTWI) respectively. This study showed that the weekly intake of methylmercury from Deep-sea Fish, Tuna and Billfish was less than the PTWI recommended by the Joint FAO/WHO expert committee on food additives.