• Journal of Korean Society of Forest Science
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• v.1 no.1
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• pp.22-29
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• 1962

(1) The objects of this study are to observe the possibility of regenerating a young merchantable pitch pine stand by sprouts and to compare the growth trend of sprouts with that of seedlings of same age grown under the almost same circumstances. (2) A plot of 20 year old pitch pine plantation, i.e. 200 trees on 0.1 ha of average D.B.H. 14 cm was clearcut at 20 cm above ground in April, 1945. By the late spring of that year sixty per cent of the cut stumps had sprouted. (3) Fourty to eighty sprouts were found on each stump (maximum:412 sprouts) at the first, but many of them had gradually died out leaving only four to five sprouts per stump by the time of three years after cutting. At that time only one vigorous sprout was left per stump by eliminating the weaker ones. (4) The sprouts, as they grew, started to cover the old stumps with new tissues developed from lower part of sprouts;consequently forming new root systems from the base of new tissues, and they appeared to be seedlings. When the age of sprouts was thirteen years old, the old stumps were completely decayed away and the reproduced stand from sprouts was averaged at 9.7 cm in D.B.H. and at 5.5m in height. (5) When the age of sprouts was thirteen years old, the sprouts exceeded the seedlings in both of total present growth and mean annual increment in height, volume, D.B.H. and basal area, but the seedlings began to exceed the sprouts in current annual increment of height, volume, D.B.H. and basal area at about ten years of age. The rates of increment of the seedling in height, volume, ect. were larger than those of sprouts except when they were one to four years old. From above facts, the following may be concluded: (1) In regenerating a pitch pine stand by sprouts, the lower the stump height, the better the result. (2) If no light limit exists, regenerating a pitch pine stand by sprouts is well possible even at the age of 20 year. (3) Pitch pine reproduction started from sprouts exceeds the seedlings of same age in growth under the almost same circumstances until they get ten years of age.

• Progress in Medical Physics
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• v.23 no.4
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• pp.219-228
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• 2012

The tangential breast intensity modulated radiotherapy (T-B IMRT) technique, which uses the same tangential fields as conventional 3-dimensional conformal radiotherapy (3D-CRT) plans with physical wedges, was analyzed in terms of the calculated dose distribution feature and dosimetric accuracy of beam delivery during treatment. T-B IMRT plans were prepared for 15 patients with breast cancer who were already treated with conventional 3D-CRT. The homogeneity of the dose distribution to the target volume was improved, and the dose delivered to the normal tissues and critical organs was reduced compared with that in 3D-CRT plans. Quality assurance (QA) plans with the appropriate phantoms were used to analyze the dosimetric accuracy of T-B IMRT. An ionization chamber placed at the hole of an acrylic cylindrical phantom was used for the point dose measurement, and the mean error from the calculated dose was $0.7{\pm}1.4%$. The accuracy of the dose distribution was verified with a 2D diode detector array, and the mean pass rate calculated from the gamma evaluation was $97.3{\pm}2.9%$. We confirmed the advantages of a T-B IMRT in the dose distribution and verified the dosimetric accuracy from the QA performance which should still be regarded as an important process even in the simple technique as T-B IMRT in order to maintain a good quality.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1993.05a
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• pp.97-97
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• 1993

Primary tumor arises infrequently in the parotid gland and generally, only about 20 to 40 percent of which prove to be malignant. They are characterized by histopathologic diversity, slow tumor growth, significant proportion of patients who have received previous treatment elsewhere. We have reviewed retrospectively 101 cases of parotid gland tumors which were treated for the recent eight years (1985-1992), Non-neoplastic tumor-like lesions were all excluded.

• The korean journal of orthodontics
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• v.30 no.4 s.81
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• pp.441-452
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• 2000

The present studies were performed to investigate the interaction of $17{\beta}$-estradiol and human growth hormone(hGH) on the proliferation of human periodontal ligament(WDL) cell. The independent effects of $17{\beta}$ estradiol and hGH on hPDL cell proliferation were investigated and the effects of hGH on hPDL cell proliferation after $17{\beta}$-estradiol pre-treatment were also investigated. Lastly, the change of hGH receptor expression in hPDL cell after $17{\beta}$-estradiol pre-treatment were investigated. The obtained results were as follows; 1. The treatment of $17{\beta}$-estradiol or hGH had no significant effects on hPDL cell proliferation. 2. After pre-treatment of $17{\beta}$-estradiol, hGH stimulated the proliferation of the hPDL cell, regardless of hHG concentration. 3. Although there was not hGH receptor in the hPDL cell, hGH receptors were expressed in hPDL cell after more than 6 hours pre-treatment of $17{\beta}$-estradiol. 4. The effect of hGH on hPDL cell proliferation was related to the hGH receptor expression. $17{\beta}$-estradiol pre-treaaent contributed to the hGH effects on the hPDL cell by stimulating hGHR expression.

• Journal of dental hygiene science
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• v.10 no.5
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• pp.403-409
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• 2010

The purpose of this study was to examine the teaching efficiency of clinical training for dental hygiene students in Gyeonggi Province. The subjects in this study were 371 dental hygiene juniors in seven different colleges in Gyeonggi Province, on whom a self-administered survey was conducted. The collected data were analyzed with a SPSS WIN 12.0 program, and the findings of the study were as follows: 1. The teaching efficiency of clinical training that the dental hygiene students undergone was on the average. As for evaluation of the factors of teaching efficiency, they gave the highest marks to the role model factor(3.40). 2. The size of the institutions where they received clinical training made no statistically significant differences to the teaching efficiency of their clinical training. The university hospitals ranked first in professional knowledge, one of the sub-directory of teaching efficiency, and the gap between them and the others was statistically significant(p=.005). 3. Concerning links between satisfaction level with the major and view of teaching efficiency, stronger satisfaction with the major led to better perception of teaching efficiency(p=.001). Among the subdirectory of teaching efficiency, that made statistically significant differences to view of interpersonal skills, performance as a supporter, fair evaluation, academic organization skills(p=.005), encouragement and support, teaching methods, professional academic knowledge(p=.001), communicative competency, performance as a role model and cooperation with the staff of dental clinics(p=.000). 4. There were no statistically significant gaps in teaching efficiency according to teaching styles. Among the sub-directory of teaching efficiency, statistically significant differences were found only in encouragement and support(p=.005). The above-mentioned findings suggest that the teaching efficacy of the clinical training was approximately on the average, and that a better satisfaction with the major led to a higher teaching efficacy. Therefore a wide variety of teaching methods and systematic training programs should be developed to boost the quality of clinical training to improve its teaching efficacy.

• Tuberculosis and Respiratory Diseases
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• v.44 no.3
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• pp.601-610
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• 1997

Background : Monocytes/macrophages play a central role in determining the host response during Gram-negative infection through secretion of a variety of mediators after stimulation of LPS. Even though cytokine production has been shown to play an important role in host defense during sepsis, cytokine release may also lead to tissue injury. Thus, regulation of macrophage response to LPS is critical for host survival during Gram-negative sepsis. In animals exposed to nonlethal doses of endotoxin, a characteristic hyporesponsiveness to subsequent administration of endotoxin has been observed. This phenomenon was known as 'LPS tolerance'. However, little information is available regarding the underlying mechanism of LPS tolerance. Method : Peripheral blood monocyte(PBMC) was isolated from peripheral blood of normal volunteers by adhesion purification method. To evaluate the conditions to obtain LPS tolerance, preculture was carried out with LPS at 10ng/ml for 24 hours. For stimulation, culture plates were washed two times and were stimulated with LPS at $1{\mu}g/ml$ for 4, 6 and 26 hours. To assess the underlying mechanisms of LPS tolerance, autologous serum, PMA, anti-CD14 Ab, Indomethacin or $PGF_2$ were added to preculture solution respectively. Cytokine concentrations in culture supernatants were measured using ELISA for TNF-$\alpha$ and IL-8 and mRNA of TNF-$\alpha$ and IL-8 were determined by Northern blot analysis. Results : The exposure of PBMC to low dose of LPS suppressed the cytokine production and mRNA expression of TNF-$\alpha$, but not IL-8. Anti-CD14 Ab partially recovered production of TNF-$\alpha$ which was suppressed by preculture with low dose LPS. The preculture with PMA induces LPS tolerance, as preculture with low dose LPS. Conclusion : LPS tolerance to TNF-$\alpha$ is regulated pretranslationally and is influenced by protein kinase C pathway and CD14.

• Tuberculosis and Respiratory Diseases
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• v.50 no.1
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• pp.76-83
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• 2001

Background : Coal workers' pneumoconiosis is a fibrotic lung disease resulting from chronic inhalation of coal dust. The precise mechanism of lung fibrosis in coal workers' pneumoconiosis is uncertain. However, a relationship between the stimulation of fibroblast proliferation and collagen production by mediators released from in flammatory and resident lung cells is thought to be a major factor. The transforming growth factor-$\beta$(TGF-$\beta$), a multifunctional cytokine and growth factor, plays a key role in the scarring and fibrotic processes due to its ability to induce extracellular matrix proteins and modulate the growth and immune function of many cell types. To determine the involvement of TGF-$\beta$ in the development of lung fibrosis in coal workers' pneumoconiosis, the TGF-${\beta}_1$ level in plasma was measured in patients with coal workers' pneumoconiosis. Methods : Plasma was collected from 40 patients with coal workers' pneumoconiosis (20 with simple coal workers' pneumoconiosis and 20 with complicated coal workers' pneumoconiosis) and from 10 normal controls. The ELISA method was used to measure the plasma TGF-${\beta}_1$ concentration. Results : Compared to the control group ($0.63{\pm}01.8$ ng/mL), there was no significant difference in the plasma TGF-${\beta}_1$ level in patients with simple coal workers' pneumoconiosis ($0.64{\pm}0.17$ ng/mL) (p>0.05). However, in patients with complicated coal workers' pneumoconiosis the plasma TGF-${\beta}_1$ level ($0.79{\pm}0.18$ ng/mL) was significantly higher than in patients with simple coal workers' pneumoconiosis and the control group (p<0.05). Conclusion : The data suggests that TGF-${\beta}_1$ has some influence in the development of lung fibrosis in coal workers' pneumoconiosis.

• Tuberculosis and Respiratory Diseases
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• v.52 no.1
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• pp.5-13
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• 2002

Background: DNA repair plays a crucial role in protecting the genome from cancer-causing agents. Therefore, a reduced DNA repair capacity can increase the susceptibility to cancer. The human OGG1 (hOGG1) gene encodes DNA glycosylase/apurinic lyase and excise 8-hydroxyguanine, one of the major premutagenic DNA lesions, which is produced by oxygen radical forming agents including smoking. Recently several polymorphisms in the hOGG1 gene were identified, and it is possible that these polymorphism') may affect the DNA repair capacity and thus modulate cancer susceptibility. The relationship between the codon 326 polymorphism (Ser to Cys) in the hOGG1 gene and lung cancer risk was investigated. Materials and Method: The Ser326Cys genotypes were determined using PCR-RFLP analysis in 299 primary lung cancer patients and 186 healthy controls who were frequency (case:control=3:2) matched according to age and sex. Result: The frequencies of the Ser326Cys genotypes (Ser/Ser, Ser/Cys and Cys/Cys) among cases (23.4%, 51.8%, and 24.7%, respectively) were not significantly different from those among the controls (22.6%,52.1% and 25.3%, respectively). When the analyses were stratified according to age, sex, smoking status and packyears of smoking, no significant association between this polymorphism and lung cancer risk was found. Moreover, the Ser326Cys genotype showed no apparent relationship with any of the histological types of lung cancer. Conclusion: These result suggest that the hOGG1 Ser326Cys polymorphism is not a major contributor to individual lung cancer susceptibility in Koreans.

• Tuberculosis and Respiratory Diseases
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• v.58 no.4
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• pp.352-358
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• 2005

Microsatellites are short tandem repeated nucleotide sequences that are present throughout the human genome. Variations in the repeat number or a loss of heterozygosity around the microsatellites have been termed a microsatellite alteration (MA). A MA reflects the genetic instability caused by an impairment in the DNA mismatch repair system and is suggested to be a novel tumorigenic mechanism. A number of studies have reported that MA in the DNA extracted from the plasma occurs at varying frequencies among patients with a non-small cell lung carcinoma (NSCLC). The genomic DNA from 9 subjects with a non-small cell lung cancer (squamous cell cancer 6, adenocarcinoma 2, non-small cell lung cancer1) and 9 age matched non-cancer control subjects (AMC: tuberculosis 3, other inflammatory lung disease 6) and 12 normal control subjects (NC) were extracted from the peripheral blood leukocytes and plasma. Three microsatellite loci were amplified with the primers targeting the Gene Bank sequence D21S1245, D3S1300, and D3S1234. MA in the form of an allelic loss or a band shift was examined with 6% polyacrylamide gel electrophoresis and silver staining. None (0/12) of the NC subjects less than 40 years of age showed a MA in any of the three markers, while 88.9%(8/9) of the AMC above 40 showed a MA in at least one of the three markers (p<0.05). Sixty percent(6/10) of the control subjects with a smoking history showed a MA in one of the three markers, while 9.1%(1/11) of the control subjects without smoking history showed a MA (p<0.05). However, not only did 66.7%(6/9) of lung cancer patients show a MA in at least one of the three markers but so did 88.9%(8/21) of the AMC patients (p>0.05). In conclusion, a MA in the D21S1245, D3S1300, and D3S1234 loci using DNA extracted from the plasma was detected in 66.7% of lung cancer while no MA was found in the young non-smoking control subjects. However, many of the non-cancer control subjects (aged smokers) also showed a MA, which compromised the specificity of the MA analysis as a screening test. Therefore, a further study with a larger sample size will be needed.

• Journal of the Korean Geographical Society
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• v.31 no.1
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• pp.19-37
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• 1996

This paper aims at examining the regional difference of changes in the business organization of retailing in the Seoul metropolitan areas, as an attempt to understand regional structure of retailing within metropolitan areas showing the trend of suburbanization. On the national level, retail sales have concentrated on the large metropolitan areas, especially on the Seoul metropolitan area, with the concentration of population and income. Within metropolitan areas, the suburbanization of retailing has made the larger structure of retail and multi-store retail appeared. In order to confirm such phenomenon, this paper is to analyze and to compare the industrial composition of retailing using industry data of 1979 and 1991. And this paper is to analyze the regional changes in the characteristics of business organization of retailing, with the index including the percentages of establishments with less than under four employees, juridical establishments, employees of ordinary times, and the annual sales per establishment of detailing. The characteristics of business organization of retailing in analyzed by principal components analysis, and the types with component in each district (city, county, ward) is analyzed by cluster analysis(Ward method). The data of 1979 were obtained from the statistics in the Census of Wholesale and Retail Trade published by the National Bureau of Statistics of Economic Planning Board, and that of 1991 were obtained from the statistics in the Report on Establishment Census (Vol.3 Wholesale and Retail Trade) published by the National Statistics Office. The following are resultant findings. 1. In Seoul metropolitan area, changes in the industrial composition of retailing with annual sales from, 1979 to 1991 show very higher composition rates of 'general merchandise stores' and 'retailing of personal transport equipment and gasoline service stations', but comparatively lower composition rates of 'retailing of food, beverages and tobacco', 'retailing of textiles, clothing, footwear and apparel accessaries', 'general retail trade, n.e.c.',and 'retailing of household fuel'. 2. The characteristics of business organization of retailing in Seoul metropolitan area presents the prevailence of small, personal business organization and especially larger employees of ordinary times. 3. Business components of retailing by principal components analysis in Seoul metropolitan area are follows: 1 All retaining industries are larger business scale. 2. Larger business take the 'retailing of taxtiles, clothing, footwear and apparel accessories', 'retailing of furniture, home furnishing and equipment', and 'retailing of jewellery and watches' is main characteristic legal organization and employees of ordinary times. 4. Types changes in business organization of retailing in Seoul metropolitan area represent legal organization and employees of ordinary times taking the 'retailing of textiles, clothing, footwear and apparel accessories', 'retailing of furniture, home furnishing and equipment',and 'retailing of jewellery and equipment', and 'retailing of jewellery and watches', and legal organization taking 'general retail trade, n.e.c.' in 1979. All retailing industries are changed into larger business scale, in 1991. These phenomena of business changes appeared southeastern regions in Kyunggi-do(province). And larger business scale taking the 'retailing of textiles, clothing, footwear and apparel accessories', 'retailing of jewellery and watches', and 'general retail trade, n.e.c.; are appeared in the legal organization in 1979. 'Retailing of personal transport equipment and gasoline service stations' are appeared in employees of ordinary times in 1991. These phenomena of business changes in appeared in eastern and northern regions in Kyunggi-do. 5. Changes in the business organization of retailing in Seoul metropolitan area is appeared in legal organization and employees of ordinary times for some industries in 1979, larger business scale of retailing and employees of ordinary times in 'retailing of personal transport equipment and gasoline service stations' are the characteristics in 1991.