• Korean Journal of Remote Sensing
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• v.37 no.6_1
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• pp.1739-1756
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• 2021

Atmospheric nitrogen dioxide (NO₂) is mainly caused by anthropogenic emissions. It contributes to the formation of secondary pollutants and ozone through chemical reactions, and adversely affects human health. Although ground stations to monitor NO₂ concentrations in real time are operated in Korea, they have a limitation that it is difficult to analyze the spatial distribution of NO₂ concentrations, especially over the areas with no stations. Therefore, this study conducted a comparative experiment of spatial interpolation of NO₂ concentrations based on two linear-regression methods(i.e., multi linear regression (MLR), and regression kriging (RK)), and two machine learning approaches (i.e., random forest (RF), and support vector regression (SVR)) for the year of 2020. Four approaches were compared using leave-one-out-cross validation (LOOCV). The daily LOOCV results showed that MLR, RK, and SVR produced the average daily index of agreement (IOA) of 0.57, which was higher than that of RF (0.50). The average daily normalized root mean square error of RK was 0.9483%, which was slightly lower than those of the other models. MLR, RK and SVR showed similar seasonal distribution patterns, and the dynamic range of the resultant NO₂ concentrations from these three models was similar while that from RF was relatively small. The multivariate linear regression approaches are expected to be a promising method for spatial interpolation of ground-level NO₂ concentrations and other parameters in urban areas.

• Radiation Oncology Journal
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• v.18 no.2
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• pp.92-100
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• 2000

Purpose :This study was performed to determine the optimal treatment velum of Patients treating with radiation therapy for intracranial germ cell tumor. Materials and Methods : From 1993 to 1998, 19 patients with intracranial germ cell tumors treated by gamma knife radiosurgery were analyzed. The location of tumor was as follows; 9 cases on pineal region, 1 case on suprasellar region, and 9 cases of multiple lesion. 7 patients were pathologically verified; 5 cases of germ cell tumor and 2 cases of non germinomatous germ cell tumor. Tumor volume was ranged from 2.4 cm$^{3}$ to 74 cm$^{3}$. Irradiation dose was 10 Gy to 20 Gy with 50% isodose curve. Follow up period was 10 months to 54 months. Results : Recurrences were observed in 14 cases among 19 (74%) patients. Complete remission and partial remission were achieved in 2 (11%) and 10 (53%) respectively. No response was observed in 7 (36%). 2 cases were recurred within original tumor bed. 6 cases were recurred beyond but contiguous with tumor bed. Ventricular relapses separated from pretreatment tumor bed were 3. Spinal recurrences were 4. Among 8 recurred cases of which tumor volume is smaller than 20 cm$^{3}$, 2 were recurred within original tumor bed, 4 were recurred beyond but contiguous with tumor bed, and 1 spinal recurrence. Meanwhile, 6 cases of which tumor volume larger than 20 cm3, 1 case was recurred beyond but contiguous with tumorbed, 2 ventricular recurrences separated with original tumor bed, and 3 spinal recurrences. 5 cases which did not show any recurrence sign showed characteristics of single lesion, tumor volume smaller than 20 cm$^{3}$ and normal tumor marker. All of 4 cases of spinal recurrences happened in the case having ventricular invasion or lesion. Among 9 cases having multiple lesion, only 3 cases recurred within original tumor bed or around tumor bed, the other 6 cases recurred separated from pretreatment tumor bed. Conclusion : Gamma knife radiosurgery is not recommended for the treatment of intracranial germ cell tumor. It is because of small treatment volume and inadequate radiation dose that are characteristics of gamma knife radiosurgery. Tumor volume, ventricular invasion or ventricular lesion in multiple lesion are important factors to be considered for the wide field radiation therapy Tumor volume smaller than 20 cm$^{3}$, single lesion, no ventricular lesion or invasion, and normal tumor marker are ideal indications for small involved field radiation therapy. Prophylactic spinal irradiation seems to be necessary when there is ventricular lesion, ventricular invasion, and multiple lesions. When the tumor volume is larger than 20 cm$^{3}$, multiple lesions, abnormal tumor marker, and whole ventricular irradiation or partial brain irradiation would be possible and neoadjuvant chemotherapy would be most beneficial in these group.

• Tuberculosis and Respiratory Diseases
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• v.44 no.4
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• pp.871-888
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• 1997

Background : It is now thought that the earliest manifestation of idiopathic pulmonary fibrosis is alveolitis, that is, an accumulation of inflammatory and immune effector cells within alveolar walls and spaces. Inflammatory cells including alveolar macrophages and resident normal pulmonary tissue cells participate through the release of many variable mediators such as inflammatory growth factors and cytokines, which contribute to tissue damage and finally cause chronic pulmonary inflammation and fibrosis. This study was performed to investigate the source and distribution pattern of transforming growth factor-${\beta}_1$(TGF-${\beta}_1$), platelet derived growth factor(PDGF), basic fibroblast growth factor(bFGF), interleukin 1(IL-1), interleukin 6(IL-6), tumor necrosis factor-$\alpha$ (TNF-$\alpha$) and the role of these mediators on bleomycin(BLM)-induced pulmonary injury and fibrosis in rats. Method : Wistar rats were divided into three groups(control group, BLM treated group, BLM and vitamine E treated group). Animals were sacrificed periodically at 1, 2, 3, 4, 5, 7, 14, 21, 28 days after saline or BLM administration. The effects were compared to the results of bronchoalveolar lavage fluid analysis, light microscopic findings, immunohistochemical stains for six different mediators(TGF-${\beta}_1$, PDGF, bFGF, IL-1, IL-6 and TNF-$\alpha$) and mRNA in situ hybridization for TGF-${\beta}_1$. Results : IL-1 and IL-6 are maximally expressed at postbleomycin 1~7th day which are mainly produced by neutrophils and bronchiolar epithelium. It is thought that they induce recruitment of inflammatory cells at the injury site. The expression of IL-1 and IL-6 at the bronchiolar epithelium within 7th day is an indirect evidence of contribution of bronchiolar epithelial cells to promote and maintain the inflammatory and immune responses adjacent to the airways. TNF-$\alpha$ is mainly produced by neutrophils and bronchiolar epithelial cells during 1~5th day, alveolar macrophages during 7~28th day. At the earlier period, TNF-$\alpha$ causes recruitment of inflammatory cells at the injury site and later stimulates pulmonary fibrosis. The main secreting cells of TGF-${\beta}_1$ are alveolar macrophages and bronchiolar epithelium and the target is pulmonary fibroblasts and extracellular matrix. TGF-${\beta}_1$ and PDGF stimulate proliferation of pulmonary fibroblasts and TGF-${\beta}_1$ and bFGF incite the fibroblasts to produce extracellular matrix. The vitamine E and BLM treated group shows few positive cells(p<0.05). Conclusion : After endothelial and epithelial injury, the neutrophils and bronchiolar epithelium secrete IL-1, IL-6, TNF-$\alpha$ which induce infiltration of many neutrophils. It is thought that variable enzymes and $O_2$ radicals released by these neutrophils cause destruction of normal lung architecture and progression of pulmonary fibrosis. At the 7~28th day, TGF-${\beta}_1$, PDGF, bFGF, TNF-$\alpha$ secreted by alveolar macrophages sting pulmonary fibroblasts into proliferating with increased production of extracellular matrix and finally, they make progression of pulmonary fibrosis. TNF-$\alpha$ compares quite important with TGF-${\beta}_1$ to cause pulmonary fibrosis. Vitamine E seems to decrease the extent of BLM induced pulmonary fibrosis.

• Tuberculosis and Respiratory Diseases
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• v.53 no.5
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• pp.530-541
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• 2002

Background : Pleural fluid adenosine deaminase (ADA) activity can be helpful in a differntial diagnosis of an exudative pleural effusion because it is increased in a tuberculous pleural effusion. The ADA activity is determined mainly by the lymphocyte function. Age-associated immune decline is characterized by a decrease in T-lymphocyte function. For that reason, the pleural fluid ADA level would be lower in older patients with exudative pleural effusion. This study focused on the influence of age on the pleural fluid ADA activity in patients with exudative pleural effusion. Methods : A total of 81 patients with exudative pleural effusion were enrolled in this study. In all patients, the pleural fluid ADA activity was measured using an automated kinetic method. Results : The mean age of the patients was $52.7{\pm}21.2$ years. In all patients with exudative pleural effusion, the pleural fluid ADA activity revealed a significant difference between young patients (under 65 years of age) and old patients (p<0.05), and showed a negative correlation with age (r=-0.325, p<0.05). In the 60 patients with a tuberculous pleural effusion, the pleural fluid ADA activity revealed a significant difference between the young and older patients : $103.5{\pm}36.9$ IU/L in young patients Vs. $72.2{\pm}31.6$ IU/L in old patients (p<0.05), and showed a negative correlation with age (r=-0.384, p<0.05). In the 21 patients with non-tuberculous exudative pleural effusion, the pleural fluid ADA activity of the young patients and old patients was similar : $23.7{\pm}15.3$ IU/L in young patients Vs. $16.1{\pm}10.2$ IU/L in old patients (p>0.05), and did not show any correlation with age (r=-0.263, p>0.05). The diagnostic cutoff value of pleural fluid ADA activity for tuberculous pleural effusion was lower in the older patients (25.9 IU/L) than in the younger patients (49.1 IU/L) or all patients (38.4 IU/L) with exudative pleural effusion. Conclusion : Tuberculous pleural effusion is an important possibility to consider in older patients with a clinical suspicion of a tuberculous pleural effusion, although no marked increase in the pleural fluid ADA activity is usually detected. For a diagnosis of a tuberculous pleural effusion in old patients, the cutoff for the pleural fluid ADA activity should be set lower.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.3
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• pp.49-82
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• 1965

For the stable and high yields of low-land rice in Korea, the characteristics of rice plant for the vegetative and physiological responses, plant type formation, and yield components have been studied in order to obtain the fundamental data for the improvement of cultural practices, especially for the ideal fertilizer application. Furthermore the environmental conditions in Korea including temperatures, light, precipitation, and soil conditions have been compared in the broad sense with those in Japan, and the application of nitrogen, phosphorus, potassium, silicate and other micro-nutrients were described in relation to the characteristics of environmental conditions for the improvement of fertilizer application. 1. The average yield of polished-rice per 10 are in Korea is about 204 kg and this values are much less than those in Japan and Taiwan where they produce 77% to 13% more than in Korea. The rate of yield increase a year in Korea is 4.2 kg, but in Japan and Taiwan the rates of yield increase a year are 81 % and 62%, respectively. It was also found that the coefficient of variation of yield is 7.7% in Korea, 6.7% in Japan and 2.5% in Taiwan. This means that the stability of producing rice in Korea is very low when compared with those in Japan and Taiwan. 2. It was learned from the results obtained from the 'annual yield estimation experiment' that there are big differences in the respect of plant type formations between rice crops grown in Japan and Korea. The important differences found were as follows: (1) The numbers of spikelets per 3.3 square meters are 891 in Korea and 1, 007 in Japan(13% more than in Korea). (2) The numbers of tillers per 3.3 square meters at the stage of maximum tillering are 1, 150 in Korea, but in Japan they showed 19% more than in Korea. (3) The ratio of effective tillers to total tillers is 77.5% in Korea and 74.7% in Japan, which seems to be higher in Korea than in Japan. But the ratio in Korea is very low when considered the numbers of total tillers in both countries. (4) The ratio of grain to straw is 85.4% in Korea and 96.3% in Japan. 3. The average temperatures during the growing season at the area of Suwon, Kwangjoo and Taegu are almost same as those in the district of Jookokoo(Fookoo yama) in Japan, i.e., the temperatures during the rice-growing season in Korea are similar to those in the southern-warm regions of Japan. 4. Considering the minimum temperatures at the stage of limiting transplanting, 13$^{\circ}C$, the time of transplanting might be 30 to 40 days earlier than presently practicing transplanting time, which comes around June 10. 5. The temperatures during the vegetative growth in Korea were higher than those temperatures that needed in the protein synthesis which ate the main metabolism during this stage. However, the temperatures at the time of reproductive growth was lower than the temperatures that needed in the sugar assimilation which is main metabolism in this stage. In this point of view, it might be considered that the proper time of growing rice plant in Korea would be rather earlier. 6. The temperatures and the day light conditions at the time of first tillering stage of rice plant, when planted as presenting transplanting practices, are very satisfactory, but the poor day light length, high temperatures and too wet conditions in the time of last-tillering stage(mid or last July) might cause the occurrence of disease such as blast. 7. The heading stage of rice plants at each region through nations when planted as presently practicing method comes when the day light length is short. 8. It was shown that the accumulated average air-temperature at the time of maturing stage was not enough and the heading time was too late, when considered the annual deviations of mean temperatures and low minimum temperatures. 9. The nitrogen content of each plant part at the each growing stage was very high at the stage of vegetative growth when compared with the nitrogen content at the stage of reproductive growth after heading. In this respect it was believed to be important to prevent the nutrient shortages at the reproductive stages, especially after the heading. 10. The area of unsatisfactory irrigation paddy fields and natural rain-fed paddy fields are getting reduced in Korea. The correlation between the rate of reducing unsatisfactory irrigation and natural rain-fed paddy fields and the rate of yield increase were computed. The correlation coefficients(r) between the area of unsatisfactory irrigation paddy fields and yield increase were +0.525, and between the natural rain-fed paddy fields and yield increase, +0.832 and between the unsatisfactory irrigation plus natural rain-fed paddy fields and yield increase, +0.84. And there were. highly significant positive correlations between natural rain-fed paddy fields and yield increases indicating that the less the area of natural rain-fed paddy fields, the greater the yields per unit area. 11. The results obtained from the fertilizer experiments (yield performance trials) conducted in both Korea and Japan showed that the yield of non-fertilized plots per 10 are was 231 kg in Korea and 360 kg in Japan. On the basis of this it might be concluded that the fertility of soil in Korea is lower than that in Japan. Furthermore it was. also found that the yields of non-nitrogen applied plots per 10 are were 236 kg in Korea and 383 kg in Japan. This also indicates that the yields of rice in Korea are largely depending on the nitrogen content in the soil. 12. The followings were obtained when the chemical natures of soils in both Korea and Japan were compared. (1) The content of organic matter, total nitrogen, exchangeable calcium, and magnesium in Korea were no more than the half those in Japan. (2) The content of N/2 chloride and soluble silicate in low-land soil were on the average lower in Korea. (3) The exchange capacity of bases in Korea was no more than half that in Japan. 13. It was also observed by comparing the soil nature of the soil with high yielding capacity with the soil with low yielding capacity that the exchange capacity of bases, exchangeable calcium and magnesium, potassium, phosphorus, manganese, silicate and iron were low in the soil with low yielding capacity. 14. The depth of furrow slice was always deeper in the soil with high yielding capacity, and the depth of furrow slice in Korea was also shallower than that in Japan. 15. Summarizing the various conditions mentioned previously and considering the effects of silicate and trace elements such as manganese and iron besides three elements on the physiological and plant type formation of rice crops, more realistic and more ideal fertilizing practices were proposed. proposed.