• The Korean Journal of Nuclear Medicine Technology
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• v.17 no.1
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• pp.76-79
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• 2013

Purpose: It is very important to establish the appropriate reference range in the laboratory for preventing mistakes like false positive or false negative. Because the reference range in the laboratory is standard of patient test results interpretation. Proinsulin is precursor hormone of insulin, and the importance is increasing for diagnosing diabetes or insulinoma. Proinsulin reagent used in our laboratory is produced in the USA, and the reference range provided by manufacturer was adapted to our reference range after the validation test. But, it is generally recommend for the every laboratory to establish the their own reference range. So, we decided to re-evaluate the reference range with our patients' test results. Materials and Methods: Among 737 patients who had been to health promotion center in our hospital between Dec. $8^{th}$ 2011 and Dec. $21^{st}$ 2011, 563 patients are chosen with exception of diabetics patients and patients showing abnormal test results in Fasting Glucose, HbA1c, Insulin, and C-peptide. The 563 test results (275 males and 288 females) were classified with three groups(entire, male, female), and analysis of normal distribution was performed with aid of SPSS(version 19.0). Because Each group didn't show normal distribution, the reference range was set from the lowest limit of 2.5% to the highest limit of 97.5% with Percentile method used in non-normal distribution. Results: When evaluation values are sorted in ascending order, the entire range is 4.5~52.0 pM and 5.3~51.9 pM for male and 4.5~52.0 pM for female. The calculated reference range with percentile method shows 6.7~26.5 pM for entire group, 6.8~26.5 pM for male and 6.7~26.5 pM for female, respectively. Conclusion: The reference range provided by reagent manufacturer is 6.4~9.4 pM and the one established in this study is 6.7~26.5 pM. This difference might be caused by racial characteristics between Western people and Koreans. So an ideal reference range can be gotten with normal population visiting to every hospital. Our hospital has been using the newly re-establishing reference range under consultation with the department of endocrinology since Aug. $1^{st}$ 2012.

• Korean Journal of Ecology and Environment
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• v.36 no.3 s.104
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• pp.322-335
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• 2003

Nutrient fluxes and sediment oxygen demands (SOD) were measured with intact sediment cores collected from three stations in the downstream of Nagdong River. The sediments were subjected to controlled oxic and hypoxic conditions and temperature gradients (from $10^{\circ}C$ to $30^{\circ}C$) of the overlying waters in laboratory batch system. The effect of temperature and labile layer thickness of the sediment on SOD were examined. $PO_4\;^{3-}$ and $NH_4\;^+$ fluxes were elevated above $20^{\circ}C$ and large mobilities were observed when they were coupled with a hypoxic and high-temperature condition. In the well oxygenated conditions, $PO_4\;^{3-}$ fluxes were negative or negligible but $NH_4\;^+$ fluxes ranged from 1.3 mg N $m^{-2}\;hr^{-1}$ to 2.3 $m^{-2}\;hr^{-1}$. Temperature quotients($Q_{10}$) of $PO_4\;^{3-}$ fluxes were 3.7 ${\sim}$ 7.3 ranges to have the most high values. $PO_4\;^{3-}$ and $NH_4\;^+$ fluxes had the logarithmic increase with temperature, while $NO_3\;^-$ was negatively absorbed to the sediment and linearly correlated with the temperature. $SiO_2$ fluxes showed no difference among oxic and hypoxic conditions and sediment texture. The nutrient fluxes would be closely correlated with pore water chemistry of sediments and activated by the top sediment layer composition such as labile organic matters or algal detritus. The ecological implications of the nutrient fluxes were discussed in terms of sources and sinks of nutrients coupled to algal productions in the Nagdong River.

• Korean Journal of Ecology and Environment
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• v.46 no.2
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• pp.145-153
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• 2013

It is a global trend that the water management policy is shifting from a water quality-oriented assessment to the aquatic ecosystem-based assessment. The majority of aquatic ecosystem assessment systems were developed solely based on physicochemical factors (e.g., water quality and bed structure) and a limited number of organisms (e.g., plankton and benthic organisms). Only a few systems use plants for a health assessment, although plants are sensitive indicators reflecting long-term disturbances and alterations in water regimes. The development of an assessment system is underway to evaluate and manage lakes as ecosystem units in the Korean Ministry of Environment. We reviewed the existing multivariate health assessment methods of other leading countries, and discussed their applicability to Korean lakes. The application of multivariate assessment methods is costly and time consuming, in addition to the correlation problem among variables. However, a single variable is not available at this moment, and the multivariate method is an appropriate system due to its multidimensional evaluation and cumulative data generation. We, therefore, discussed multivariate assessment methods in three steps: selecting metrics, scoring metrics and assessing indices. In the step of selecting metrics, the best available metrics are species-related variables, such as composition and abundance, as well as richness and diversity. Indicator species, such as sensitive species, are the most frequently used in other countries, but their system of classification in Korea is not yet complete. In terms of scoring metrics, the lack of reference lakes with little anthropogenic impact make this step difficult, and therefore, the use of relative scores among the investigated lakes is a suitable alternative. Overall, in spite of several limitations, the development of a plant-based multivariate assessment method in Korea is possible using mostly field research data. Later, it could be improved based on qualitative metrics on plant species, and with the emergence of further survey data.

• The Korean Journal of Food And Nutrition
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• v.29 no.4
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• pp.474-479
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• 2016

This study aimed to investigate the concentration of vitamin C in Momordica charantia (MC) by cultivar, harvest time, and maturity. The methods for determining vitamin C levels were validated by measuring their linearity, specificity, limit of detection (LOD), limit of quantification (LOQ), precision, and accuracy using HPLC. Results showed high linearity in the calibration curve, with a coefficient of correlation ($R^2$) of 0.9994. The LOD and LOQ values for vitamin C were 0.05 and $0.16{\mu}g/mL$, respectively. The relative standard deviations (RSDs) for intra- and inter-day precision of vitamin C measurements were 2.34 and 1.34%, respectively. Depending on cultivar, the concentration of vitamin C in MC varied from 20.75~107.31 mg/100 g, fresh weight, with an average level $68.85{\pm}25.57mg/100g$, FW. When MC was analyzed by harvest time, the 20150612 MC showed the highest amount of vitamin C ($113.20{\pm}1.89mg/100g$, FW). On the other hand, the highest vitamin C content by maturity was $48.59{\pm}0.87mg/100g$, FW (15 day old MC). This information on the comparative vitamin C levels of MC might be useful to food scientists and should be explored for functional food development.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.63 no.3
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• pp.196-204
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• 2018

The main objective of this study was to identify the best quality rice for cultivation on reclaimed land in Jeollabukdo-Province based on yield, head rice ratio, protein content, amylose content, and Toyo taste value evaluations. Seven varieties of rice were grown for two years on the reclaimed land. The Sukwang variety had the earliest heading date. The tiller number for the Younghojinmi variety was 19 on average, and its variation in tiller number was the lowest, which showed that the safety for cultivation of the variety was high on the reclaimed land with respect to that of the other varieties. The culm and panicle lengths of the Sukwang and Hyunpum varieties were the highest at 81.8 and 21.3 cm, respectively. Shindongjin produced the highest thousand grain weight at 27.7 g, whereas Haepum produced the lowest at 22.3 g. The number of grains per panicle for 7 all varieties was statistically equal for both years. The yield order for the varieties was Shindongjin (590) > Hopum (575) > Younghojinmi (552) > Sukwang (551) > Hopum (543) > Mipum (534) > Haepum (498 kg/10a), which showed that there was no significant difference in average yield between the varieties when both years are taken into consideration. However, the annual difference in Haepum yield between 2015 and 2016 was the highest at 108 kg/10a, indicating low cultivation safety. The head rice ratio of Younghojinmi was higher than for the other cultivars in both 2015 and 2016. However, there was no significant difference between the 2 years when the averages for all varieties were analyzed. There was was a considerable difference in protein and amylose content between the varieties in the two years, although this was not apparent in the results when the average over 2 years for each variety was calculated. There was no significant difference between the two years with respect to the average head rice ratio, and the protein and amylose contents of the seven varieties. The Toyo taste values for the Sukwang and Mipum varieties were higher than for the other varieties. Based on the principle characteristics, such as Toyo value, the Sukwang variety is a suitable substitute for Shindongjin, which has been previously used to produce high-quality rice on the reclaimed land.

• Korean Journal of Environmental Biology
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• v.38 no.2
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• pp.207-215
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• 2020

Toxic assessment of antifouling agents (diuron and irgarol) was conducted using the fertilization and the normal embryogenesis rates of the sea urchin, Mesocentrotus nudus. Bioassessment began with male and female reproductive cell induction. White or cream-colored male gametes(sperm) and yellow or orange-colored female gametes (eggs) were acquired and fully washed, separately. Then, the fertilization and normal embryogenesis rates were measured after 10 min and 48 h of exposure to the toxicants, respectively. The fertilization and embryo development rates were greater than 90% in the control, validating the suitability of both endpoints. The normal embryogenesis rates were significantly decreased with increasing concentrations of diuron and irgarol, but no changes in the fertilization rates were observed in concentrations ranging from 0 to 40 mg L^-1. The EC₅₀ values of diuron and irgarol for the normal embryogenesis rates were 20.07 mg L^-1 and 22.45 mg L^-1, respectively. The no observed effect concentrations (NOEC) were <1.25 mg L^-1 and the lowest observed effect concentrations (LOEC) were 1.25 mg L^-1 and 2.5 mg L^-1, respectively. From these results, concentrations of diuron and irgarol over 1.25 mg L^-1 and 2.5 mg L^-1, respectively, can be considered to have toxic effects on invertebrates, including M. nudus. The ecotoxicological bioassay in this study using the noted fertilization and normal embryogenesis rates of M. nudus can be used as baseline data for the continued establishment of environmental quality standards for the effects of antifouling agents(especially diuron and irgarol) in a marine environment.

• The Korean Journal of Nuclear Medicine Technology
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• v.16 no.2
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• pp.49-56
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• 2012

Purpose : Gated myocardial perfusion SPECT provides not only myocardial perfusion status, but various functional parameters of left ventricle (LV). The purpose of this study was to analyze ejection fraction (EF) for correlation and difference between $^{201}Tl$ gated myocardial perfusion SPECT and echocardiography depending on extent of perfusion defect, gender and LV volumes. Materials and Methods : From April 2011 to May 2012, we analyzed 291 patients (male:female =165:126; mean: $64.6{\pm}10.8$ years) who were examined both $^{201}Tl$ gated myocardial perfusion SPECT and echocardiography at less than 7 days apart in our hospital. 101 patients showed perfusion defect and the rest of the people without any defect. We applied automatic analysis (Quantitative gated SPECT, QGS), and calculated EF, End-diastolic volume (EDV) and End-systolic volume (ESV) from Stress (G-Stress) and Rest (G-Rest) studies. And we analyzed the correlation and difference for EF between $^{201}Tl$ gated SPECT and echocardiography. Results : The correlation of LVEF among G-Stress, G-Rest and echocardiography was quite a good (G-Stress vs. G-Rest: r=0.909, G-Stress vs. echocardiography: r=0.833, G-Rest vs. echocardiography: r=0.825). And there were significant differences in EDV, ESV and EF in total patients (p<0.01). The normal group showed significant difference in EF (p<0.01) and the group with perfusion defect also demonstrated significant difference (a group with reversible defect: p<0.01, fixed defect: p<0.01) depending on extent of perfusion defect. We analyzed difference in normal group by gender. In normal group, there was no significant difference (p>0.05) in EF from men. However, there was a significant difference (p<0.01) from women. When we classified two groups by average size of EDV in Korean women, there was no significant difference in a group of above average size of EDV (p>0.05). Conclusion : When compared among Stress and Rest of $^{201}Tl$ gated SPECT and echocardiography, we confirmed that there was a good correlation for LVEF. But there were significant differences among three studies. And extent of perfusion defect, gender and LV volumes are independent determinants of the accuracy of LVEF. So, it is hard to compare and interchange quantitative indices among modalities. We should take additional researches to prove results of our study.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.1
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• pp.111-114
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• 2010

Purpose: There has been recent interest in the radioactivity uptake and image acquisition of radioactivity concentration. The degree of uptake is strongly affected by many factors containing $^{18}F$-FDG injection volume, tumor size and the density of blood glucose. Therefore, we investigated how radioactivity uptake in target influences 2D or 3D image analysis and elucidate radioactivity concentration that mediate this effect. This study will show the relationship between the radioactivity uptake and 2D,3D image acquisition on radioactivity concentration. Materials and Methods: We got image with 2D and 3D using 1994 NEMA PET phantom and GE Discovery(GE, U.S.A) STe 16 PET/CT setting the ratio of background and hot sphere's radioactivity concentration as being a standard of 1:2, 1:4, 1:8, 1:10, 1:20, and 1:30 respectively. And we set 10 minutes for CT attenuation correction and acquisition time. For the reconstruction method, we applied iteration method with twice of the iterative and twenty times subset to both 2D and 3D respectively. For analyzing the images, We set the same ROI at the center of hot sphere and the background radioactivity. We measured the radioactivity count of each part of hot sphere and background, and it was comparative analyzed. Results: The ratio of hot sphere's radioactivity density and the background radioactivity with setting ROI was 1:1.93, 1:3.86, 1:7.79, 1:8.04, 1:18.72, and 1:26.90 in 2D, and 1:1.95, 1:3.71, 1:7.10, 1:7.49, 1:15.10, and 1:23.24 in 3D. The differences of percentage were 3.50%, 3.47%, 8.12%, 8.02%, 10.58%, and 11.06% in 2D, the minimum differentiation was 3.47%, and the maximum one was 11.06%. In 3D, the difference of percentage was 3.66%, 4.80%, 8.38%, 23.92%, 23.86%, and 22.69%. Conclusion: The difference of accumulated concentrations is significantly increased following enhancement of radioactivity concentration. The change of radioactivity density in 2D image is affected by less than 3D. For those reasons, when patient is examined as follow up scan with changing the acquisition mode, scan should be conducted considering those things may affect to the quantitative analysis result and take into account these differences at reading.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.19 no.3
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• pp.180-190
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• 2014

It has been customary to exclude top 10-20% of velocity profiles in the Acoustic Doppler Current Profiler (ADCP) measurement due to side lobe effects at the boundary. To better understand the mixing in the Yeongsan estuary, the freshwater advection speed (FAS) was recovered from highly contaminated ADCP data near the surface. The velocity profiles were measured by using ADCP at two stations in the Yeongsan estuary during August 2011: one was located in front of the Yeongsan estuarine dam and the other was deployed near Goha Island. The FAS was recovered from the ADCP data set by applying rigorous post-processing methods and compared with the sediment advection speed (SAS). The SAS was determined by the peak time difference of suspended sediment concentration between two stations in the channel, divided by the distance of two stations. The FAS and the SAS showed very similar value when the freshwater discharge was greater than $2.0{\times}10^7$ ton and the SAS was a bit greater when the freshwater discharge was smaller. Since the FAS was on average about 0.8 m/s greater than the velocity at 0.8 of water depth from the bottom, the net discharge, estimated with recovered FAS and integrated over water depth and tidal cycle, was directed seaward during the high discharge contrary to the onshore direction of the net discharge estimated with 0.8 of water depth from the bottom. Moreover, the velocity shear and Richardson number changed when the FAS was used. Thus, the importance of the true FAS is appreciated in the investigation of the surface layer stability. If currents, temperature and salinity were observed for longer time in the future, it could be possible to more accurately understand the formation and decay of stratification as well as the suspended sediment transport processes.

• Journal of the Korean Society of Radiology
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• v.11 no.7
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• pp.597-603
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• 2017

High-dose $^{131}I$ therapy has been generally carried out to remove remaining thyroid tissue or to cure metastasize lesion of patients who received full thyroidectomy due to differentiated thyroid cancers. In case high-dose $^{131}I$ therapy is carried out for a patient, the patient should be hospitalized being isolated for a certain period in order to restrict the amount of exposure to radiation of people at large from the patient within the limit of a level of radiation. Effective half-life is an important value to calculate how family members are exposed to radiation from a patient or to decide the period of isolation of the patient from the family members. Therefore, in this study we calculated the effective decay constant, effective half-life and period of isolation of high-dose $^{131}I$ therapy patient using NM670 SPECT/CT. As a result of carrying out this study, the effective half-life of high-dose $^{131}I$ therapy patients was derived and the time to reach the discharge level of 1.2 GBq was confirmed. When they were compared with each other in each of curative doses, the effective half-life did not have significant difference, but the time when the level of radiation remaining in the interior of the body to reach the criteria of isolation and discharge showed significant difference and it could be confirmed that the higher the curative dose the longer the period of isolation becomes. When the effective half-lives in each type of preparation were compared with each other, they did not show significant difference. However, When the times to reach the level of radiation that is the criteria of isolation and discharge in each type of preparations, they showed significant difference. The cause of the shortening of the isolation period for rhTSH patients group is decided to be low curative dose. Accordingly, if the current national health insurance (the insurance is applied to using of rhTSH in 3.7 GBq or lower) is maintained, while discerning them in each of types of preparation, we would be able to discharge patients at the time earlier than the current period of isolation (2 nights and 3 days).