• Nuclear Medicine and Molecular Imaging
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• v.43 no.5
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• pp.429-435
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• 2009

Purpose: The purpose of this study was to assess the prognostic value of preoperative FDG-PET in colorectal cancer (CRC) patients with hepatic metastasis (HM). Materials and Methods: 24 CRC patients (M:F=14:10; age, $63{\pm}10$ yrs) with HM who had undergone preoperative FDG PET were included. Cure-intent surgery was performed in all the patients and HMs were controlled using resection (n=13), radio-frequency ablation (RFA) (n=7), and resection plus RFA (n=4). Potential prognostic markers tested were maxSUV of primary tumor, maxSUV of HM, maxSUV ratio of HM over primary tumor (M/P ratio), histologic grade, CEA level, venous/lymphatic/nerve invasion, T stage, N stage, no. of HM, no. of lymph node metastasis, and treatment modality of HM. Results: 14 CRC patients developed a recurrence with a median follow-up duration of 244 days, whereas 10 patients did not develop recurrence with a median follow-up duration of 504 days. M/P ratios but other potential prognostic markers were significantly higher in the recurrent patients ($0.72{\pm}0.14$) than recurrence-free patients ($0.54{\pm}0.23$) (p=0.038). M/P ratio only was found to predict recurrence by Cox multivariate analysis (hazard ratio 37.7, 95% confidence interval 2.01-706.1, p=0.016). The 11 patients with lower M/P ratio of <0.61 had significantly better disease-free survival rate than the 13 patients with higher M/P ratio (${\geq}0.61$) (p=0.026). Conclusion: maxSUV ratio of HM over primary tumor (M/P ratio) may be useful for prognosis prediction of CRC patients with HM. Higher FDG uptake of HM than that of primary tumor may indicate a more advanced status in stage IV CRC.

• The Journal of Engineering Geology
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• v.18 no.4
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• pp.555-566
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• 2008

Hydrogeochemical study in Samseung area (Boeun, Chungbuk) and waterrock interaction experiment using rock samples from the area were performed to elucidate the fluoride source in groundwater and explaining geochemical behavior of fluoride ion. Fluoride concentration of public water supply mostly using groundwater in Boeun area was significantly higher in South Korea. The maximum fluoride concentration of the study area was 3.9 mg/L, and 23% of samples exceeded the Korean Drinking Water Standard of fluoride (1.5 mg/L). The average concentration of fluoride was 1.0 mg/L and median was 0.5 mg/L. Because of high skewness (1.3), median value is more appropriate to represent fluoride level of this area. The relationships between fluoride ion and geochemical parameters ($Na^+$, $HCO_3$, pH, etc.) indicated that the degree of waterrock interaction was not significant. However, high fluoride samples were observed in $NaHCO_3$ type on Piper's diagram. The negative relationship between fluoride and $NO_3$ ion which might originate from surface contaminants was obvious. These results indicate that fluoride ion in groundwater is geogenic origin. The source of fluoride was proved by waterrock interaction batch test. Fluoride concentration increased up to 1.2 mg/L after 96 hours of reaction between water and biotite granite. However, the relationship between well depth and fluoride ion, and groundwater age and fluoride ion was not clear. This indicates that fluoride ion is not correlated with degree of waterrock interaction in this area but local heterogeneity of fluoriderich minerals in granite terrain. High fluoride concentration in Boeun area seems to be correlated with distribution of permeable structures in hard rocks such as lineaments and faults of this area. This entails that the deep bedrock groundwater discharges through the permeable structures and mixed with shallow groundwater.

• Magazine of the Korean Society of Agricultural Engineers
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• v.26 no.2
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• pp.69-84
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• 1984

This study was carried out to investigate the time distribution of single storms and to establish the model of storm patterns in korea. Rainfall recording charts collected from 42 metheorological stations covering the Korean peninsula were analyzed. A single storm was defined as a rain period seperated from preceding and succeeding rainfall by 6 hours and more. Among the defined single storms, 1199 storms exceeding total rainfall of 80 mm were qualified for the study. Storm patterns were cklassified by quartile classification method and the relationship between cummulative percent of rainfalls and cummulative storm time was established for each quartile storm group. Time distribution models for each stations were prepared through the various analytical and inferential procedures. Obtained results are summarized as follows: 1. The percentile frequency of quartile storms for the first to the fourth quartile were 22.0%, 26.5%, 28.9% and 22.6%, respectively. The large variation of percentile frequency was show between the same quartile storms. The advanced type storm pattern was predominant in the west coastal type storm patterns predominantly when compared to the single storms with small total rainfalls. 3. The single storms with long storm durations tended to show delayed type storm patterns predominantly when compared to the single storms with short storm durations. 4. The percentile time distribution of quartile storms for 42 rin gaging stations was estimated. Large variations were observed between the percentiles of time distributions of different stations. 5. No significant differences were generally found between the time distribution of rainfalls with greater total rainfall and with less total rainfall. This fact suggests that the size of the total rainfall of single storms was not the main factor affecting the time distribution of heavy storms. 6. Also, no significant difference were found between the time distribution of rainfalls with long duration and with short duration. The fact indicates that the storm duration was no the main factor affecting the time distribution of heavy storms. 7. In Korea, among all single storms, 39.0% show 80 to 100mm of total rainfall which stands for the mode of the frequency distribution of total rainfalls. The median value of rainfalls for all single storms from the 42 stations was 108mm. The shape of the frequency distribution of total rainfalls showed right skewed features. No significant differences were shown in the shape of distribution histograms for total rainfall of quartile storms. The mode of rainfalls for the advanced type quartile storms was 80~100mm and their frequencies were 39~43% for respective quartiles. For the delayed type quartile storms, the mode was 80~100mm and their frequencies were 36!38%. 8. In Korea, 29% of all single storms show 720 to 1080 minutes of storm durations which was the highest frequency in the frequency distribution of storm durations. The median of the storm duration for all single storms form 42 stations was 1026 minutes. The shape of the frequency distribution was right skewed feature. For the advanced type storms, the higher frequency of occurrence was shown by the single storms with short durations, whereas for the delayed type quartile storms, the higher frequency was shown gy the long duration single storms. 9. The total rainfall of single storms was positively correlated to storm durations in all the stations throughout the nation. This fact was also true for most of the quartile storms. 10. The third order polynomial regression models were established for estimating the time distribution of quartile storms at different stations. The model test by relative error method resulted good agreements between estimated and observed values with the relative error of less than 0.10 in average.

• Radiation Oncology Journal
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• v.9 no.2
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• pp.205-213
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• 1991

In order to determine the value of induction chemotherapy (CT) for inoperable head and neck cancer, the authors conducted a retrospective study. Fifty-five patients were treated with CT and radiotherapy (R-T)(CT+RT group). This group was compared with a group of 54 patients treated RT alone (RT alone group). The CT regimen used were CF (cis-platine+5-FU), CVB (cyclophos-phamide+vincristine+bleomycin), CAP (cyclophosphamide+adriamycin+prednisolone) or PVBM(cis-platine+vincristine+bleomycin+methotrexate). Toxicity from induction chemo-therapy was minimal, and toxicity was limited primarily to nausea and vomiting, mucositis and myelosuppression. The complete response (CR) rate to CT was $14.5\%$ and the partial response (PR) rate was $47.3\%$ for an overall major response rate of $61.8\%$. The major response rate at the completion of loco-regional therapy was $87.3\%$(48/55) with 32 CR ($58.2\%$) and 16 PR ($29.1\%$) for CT-RT group and $81.5\%$(44/55) with 27 CR ($50.0\%$) and 17 PR ($31.5\%$) for RT alone group (p=0.57). Median follow-up of CT-RT group was 17 months and 11 months for RT alone group. Median survival was 30 months for CT-RT group and 24 months for RT alone group (p=0.3). The overall survival rate at 2 years, 3 years and 5 years, respectively was $60.9\%,\;48.6\%\;and\;42.5\%$, for CT-RT group, and $54.9\%,\;49.9\%\;and\;49.9\%$ for RT alone group (p=0.33). Comparision between patients in both groups, stratified by overall stage, T and N stage, site, and pathology, all failed to show any significant difference in survival rates. We conclude that this retrospective study failed to demonstrate an advantage for induction chemotherapy in inoperable head and neck cancer.

• Journal of the Korean Society of Radiology
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• v.15 no.5
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• pp.591-602
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• 2021

Acute ischemic stroke(AIS) should be diagnosed within a few hours of onset of cerebral infarction symptoms using diagnostic radiology. In this study, we evaluated the clinical usefulness of SVD and the Bayesian algorithm to measure the volume of cerebral infarction using computed tomography perfusion(CTP) imaging and magnetic resonance diffusion-weighted imaging(MR DWI). We retrospectively included 50 patients (male : female = 33 : 17) who visited the emergency department with symptoms of AIS from September 2017 to September 2020. The cerebral infarct volume measured by SVD and the Bayesian algorithm was analyzed using the Wilcoxon signed rank test and expressed as a median value and an interquartile range of 25 - 75 %. The core volume measured by SVD and the Bayesian algorithm using was CTP imaging was 18.07 (7.76 - 33.98) cc and 47.3 (23.76 - 79.11) cc, respectively, while the penumbra volume was 140.24 (117.8 - 176.89) cc and 105.05 (72.52 - 141.98) cc, respectively. The mismatch ratio was 7.56 % (4.36 - 15.26 %) and 2.08 % (1.68 - 2.77 %) for SVD and the Bayesian algorithm, respectively, and all the measured values had statistically significant differences (p < 0.05). Spearman's correlation analysis showed that the correlation coefficient of the cerebral infarct volume measured by the Bayesian algorithm using CTP imaging and MR DWI was higher than that of the cerebral infarct volume measured by SVD using CTP imaging and MR DWI (r = 0.915 vs. r = 0.763 ; p < 0.01). Furthermore, the results of the Bland Altman plot analysis demonstrated that the slope of the scatter plot of the cerebral infarct volume measured by the Bayesian algorithm using CTP imaging and MR DWI was more steady than that of the cerebral infarct volume measured by SVD using CTP imaging and MR DWI (y = -0.065 vs. y = -0.749), indicating that the Bayesian algorithm was more reliable than SVD. In conclusion, the Bayesian algorithm is more accurate than SVD in measuring cerebral infarct volume. Therefore, it can be useful in clinical utility.

• Korean Journal of Optics and Photonics
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• v.33 no.4
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• pp.167-176
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• 2022

Adaptive optics (AO) systems compensate for atmospheric disturbance, especially phase distortion, by introducing counter-wavefront deformation calculated from real-time wavefront sensing or prediction. Because AO system implementations are time-consuming and costly, it is highly desirable to estimate the system's performance during the development of the AO system or its parts. Among several techniques, we mostly apply statistical analysis, computational simulation, and optical-bench tests. Statistical analysis estimates performance based on the sum of performance variances due to all design parameters, but ignores any correlation between them. Computational simulation models every part of an adaptive optics system, including atmospheric disturbance and a closed loop between wavefront sensor and deformable mirror, as close as possible to reality, but there are still some differences between simulation models and reality. The optical-bench test implements an almost identical AO system on an optical bench, to confirm the predictions of the previous methods. We are currently developing an AO system for a 1.6-m ground telescope using a deformable mirror that was recently developed in South Korea. This paper reports the results of the statistical analysis and computer simulation for the system's design and confirmation. For the analysis, we apply the Strehl ratio as the performance criterion, and the median seeing conditions at the Bohyun observatory in Korea. The statistical analysis predicts a Strehl ratio of 0.31. The simulation method similarly reports a slightly larger value of 0.32. During the study, the simulation method exhibits run-to-run variation due to the random nature of atmospheric disturbance, which converges when the simulation time is longer than 0.9 seconds, i.e., approximately 240 times the critical time constant of the applied atmospheric disturbance.

• Korean Journal of Environment and Ecology
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• v.31 no.6
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• pp.537-548
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• 2017

The purpose of this study was to investigate the species composition and the aquatic environment of Jojong Stream and Sudong Stream, which were the original habitats of Zacco koreanus population and restored population re-introduced in Bongseonsa Stream. It also compared and analyzed the states of the growth and reproductive ability of Z. koreanus habiting in each of the three streams. The investigation was conducted in June 2016 which was known as the spawning season of Z. koreanus. The results of the physical aquatic environments showed the slight differences in altitude, width and depth of water among three streams, but the bottom structure was found to be quite different in the composition of the boulder, cobble, and pebble among the streams. The result of the physicochemical aquatic environment analysis showed that there were no significant differences in water temperature, pH, DO, BOD, and EC among the three stream. In the fish fauna investigation, 530 individuals of 11 species of 3 families were collected in Bongseonsa Stream, 293 individuals of 12 species of 4 families were collected in Jojong Stream, and 361 individuals of 11 species of 4 families were collected in Sudong Stream. All three streams were dominated by Z. koreanus and Z. platypus. Six Korean endemic species appeared in each of the three streams, showing the high occurrence rate of indigenous species of 50.0% or more. The aggregation index analysis revealed that the mean dominance index ranged from 0.63 (${\pm}0.05$, BS) to 0.72(${\pm}0.01$, JJ), mean diversity index from 1.55 (${\pm}0.06$, JJ) to 1.78 (${\pm}0.11$, BS), mean evenness index from 0.71 (${\pm}0.03$, JJ) to 0.76 (${\pm}0.02$, BS), and mean richness index from 1.61 (${\pm}0.33$, JJ) to 1.73 (${\pm}0.24$, SD). The result indicated that the observed differences between the stream community indices were statistically nonsignificant. The similarity analysis showed that 75.4% similarity was divided into two groups of A and B and that the fish fauna on each analyzed point was similar. The quantitative habitat evaluation index (QHEI) analysis showed that the average value of QHEI was 151.0 (${\pm}46.0$), which means that it was a suboptimal habitat environment. The result of length-weight analysis of Z. koreanus populations showed that the regression coefficient b of the restoration population and the original habitat population were at 3.0 or higher while the condition factor had a positive slope. Moreover, it was found that the slopes of the regression coefficient b and condition factor of the original habitat population were larger than the restored population. The analysis of the length frequency distribution of the Z. koreanus population revealed that all three streams maintained the stable life cycle although it was found that the growth rate of the original habitat population was faster than the restored population in the one-year-old class. The result of the gonadosomatic index (GSI) analysis showed that the GSI median value of the Z. koreanus population in the restored habitat Bongseonsa Stream was higher than the population in the original habitat Jojong Stream and Sudong Stream for both of males and females.

• Journal of Gastric Cancer
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• v.3 no.3
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• pp.122-127
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• 2003

Purpose: The incidence rate and the mortality rate of gastric cancer have decreased in developed countries over the last several decades. On the other hand, they remain high in far eastern countries such as Korea, Japan, China and in many developing countries. The cure of patients with gastric carcinomas can be achieved mostly through complete surgical resection, but most gastric cancer patients are in advanced stages when diagnosed and have poor prognoses. therefore, the development of an effective systemic therapy is essential for far advanced gastric cancer patients. Until recently, the most commonly used combination chemotherapy was based on 5-flurouracil or cisplatin, but the results were not satisfactory, so recently etoposide, adriamycin and cisplatin (EAP-II) combination chemotherapy was introduced in patients with advanced gastric cancer. Early studies showed a high response rate and the ability to convert unresectable cases to resectable ones, but later studies couldn't duplicate the result. the purpose of this study was to evaluate the relative efficacy & toxicity of EAP-II chemotherapy and ELF chemotherapy which is based on 5-flurouracil. Materials and Methods: Between July 1992 and July 2002, sixty-five patients with inoperable advanced gastric cancer were enrolled for this study. Thirty-seven patient received EAP-II chemotherapy:etoposide (20 mg/$m^{2}$ IV for $1\∼5 days$), adriamycin (20 mg/$m^{2}$ IV for $1\∼5 days$) and cisplatin (20 mg/$m^{2}$ IV for $1\∼5 days$) and Twenty-eight patients receieved ELF chemotherapy : etoposide (100 mg/$m^{2}$ IV for $1\∼3 days$), leucovorin (20 mg/$m^{2}$ IV for $1\∼5 days$) and 5-FU (500 mg/$m^{2}$ IV for $1\∼5 days$). Each treatment schedule for each group was repeated every four weeks: EAP-II means 3.4 cycles per patient..ELF means 4.1 cycles per patient Results: Total respones rates were $5.4\%$ in the ELF group and $3.6\%$ in the EAP group (P-value>0.05). The median times to progression were 144 days in the ELF group and 92 days in the EAP-II group (P-value<0.05), and themedian overall survival times were 189 days in the ELF group and 139 days in the EAP-II group (P-value>0.05). The difference in the survival curves for the two regimens was not statistically significant. Non-hematologic toxicitis & hematologic toxicitis were more frequently observed for the EAP-II regimen. Anemia: $27.6\%$ in ELF vs $54\%$ in EAP-II; Leukopenia: $8.5\%$ in ELF vs $19\%$ in EAP-II; nausea & vomiting: $45.9\%$ in ELF vs $67.8\%$ in EAP-II. Conclusion: EAP-II regimen is not superior to ELF regimen in the tratment of inoperable advanced gastric cancer (J Korean Gastric Cancer Assoc 2003;3:122-127)

• Tuberculosis and Respiratory Diseases
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• v.45 no.2
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• pp.280-289
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• 1998

Background: It is sometimes difficult to differentiate tuberculous pleural effusion from malignant pleural effusion by clinical symptoms, signs, by routine tests of pleural fluid, and by pathologic studies. And recently, it was discovered that cytokines such as IL-2, IFN-$\gamma$, TNF-$\alpha$ are elevated in tuberculous pleural fluid, and there have been several attempts to diagnose tuberculous pleural effusion by using these immunological mediators. There are several studies regarding the diagnostic value of IFN-$\gamma$, and there are two studies in Korea. But the diagnostic values of IFN-$\gamma$ in these studies were slightly lower than those in other countries. To compare the diagnostic value of IFN-$\gamma$ with those of CEA and ADA, and to determine the sensitivity and specificity of IFN-$\gamma$ in Korean, we mesured IFN-$\gamma$, CEA level and ADA activity in pleural effusions. Methods: ADA activity, IFN-$\gamma$ level and CEA level as well as cell count, differential count, and biochemical assays such as protein content and lactate dehydrogenase were measured in 40 cases of tuberculous pleuritis and 42 cases of malignant pleural effusion. Results: Tuberculous pleural fluid showed higher levels of IFN-$\gamma$ and ADA ($832.6{\pm}357.2$ pg/ml and $82.5{\pm}25.9$ U/L, respectively) than those of malignant pleural effusion ($2.6{\pm}8.0$ pg/ml and $19.2{\pm}10.9$ U/L, respectively) (p<0.01). Malignant pleural effusions showed higher median value (102.2 ng/ml) than tubercalous pleural effusions (1.8 ng/ml) (p<0.01). The sensitivities of IFN-$\gamma$, ADA, CEA were 0.97, 0.87, 0.67 and the specificities of IFN-$\gamma$, ADA, CEA were 1.0, 0.97, 1.0, respectively. There was no significant correlation between ADA activity and IFN-$\gamma$ level. Conclusion: This study showed that IFN-$\gamma$ test would be a very useful clinical test for differential diagnosis of tuberculous pleuritis and malignant pleural effusion because it is very sensitive and specific, although it is an expensive test.

• Journal of Animal Science and Technology
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• v.61 no.3
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• pp.147-153
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• 2019

A goal for swine farming is the improvement in the number of live-born and weaned piglets per sow. Hence, the effect of parities should consider the correlation between the component traits of reproductive performance, weaning, and duration. Sows were housed in farrowing pens (W 2.2 ${\times}$ D 1.8 ${\times}$ H 1.2 m) on a partially slatted plastic floor. Twenty sows used in this study were between the first and sixth parity in gilts (P1), parity 2-5 (P3), and parity 6-9 (P6). Data collection by parity was classified into three categories: (1) reproduction performance (gestation length, total number of piglets born, number of piglets live born, number of piglets stillborn, total piglet birth weight; (2) weaning traits (weaning period, number of piglets weaning, total piglets weaning weight); (3) duration traits (farrowing duration, placenta expulsion duration, time from last piglet to first placenta, average birth interval, and tail wagging behavior). Gestation length was higher in P6 than P1 and P3 of different parity sows. The maximum value in P1 and P3 was 117 days, but the median value in P6 was 117 days (p < 0.05). The total number of piglets born (p = 0.113), number of piglets live born (p = 0.118), number of still piglets born (p = 0.151), and total piglet birth weight (p = 0.117) were not affected by parity. The number of live piglets was higher than the other parities by an average of $15.6{\pm}2.1$ in P1. The duration of farrowing was the lowest at 22.2 min in P6, but the maximum value was 42.2 min more than other parities (p = 0.355). Weaning traits of sows also did not differ significantly (p > 0.05), but the weaning period from P1 was lower than that of the other parities (p = 0.170). The number of piglets weaned was 10 heads on average in P1, P3, and P6 (p < 0.05). However, the mean values of the total piglet weaning weight (p = 0.377) of P6 (62.0 10.4 kg) were higher than those of P1 (54.9 10.2 kg) and P3 (58.4 13.6 kg). The placenta expulsion duration was higher in P6 than that in P1 and P3 (p = 0.447). The time from the last piglet to first placenta was be lower in P3 than that of the other parities (p = 0.206). The average birth interval was higher in P3 than that of the other parities (p = 0.156). Tail wagging (count) behavior was higher in P6 than in the other parities (p = 0.065). The data showed that the reproduction performance, total piglets born, and weight were higher in the gilts group, and higher in the weaning trait than that in the P6 group. This study examined the relationship between reproductive performance, birth interval and tail motion according to sow parity. Regarding duration, farrowing duration was lower in P6 than that in the other parities, but placenta expulsion and tail wagging were higher in P6 than in the other parities. Therefore, it is possible that the results from these sows could be used as basic data for effective farm management.