• KOREAN JOURNAL OF CROP SCIENCE
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• v.15
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• pp.85-97
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• 1974

In order to clarify the inducing conditions and cause of sterility in rice plants, 4 varieties were cooled at 3 different levels of temperature combined with 3 different levels of treatment period. And 19 varieties were tested to examine the varietal difference of cold resistance. The results obtained were summarized as follows; 1. There were significant varietal differences in the effect of cooling treatment at meiotic stage. Suwon 213-1 was induced heavy sterility by 3 day cooling treatment at 17.5$^{\circ}C$ whereas Hayayuki, Nongpaik and Jinheung were induced a little sterility by 3 day cooling treatment at 15$^{\circ}C$ and 5 day treatment at 17.5$^{\circ}C$. The per cent of grain fertility was correlated significantly with the delayed days to heading, the degree of panicle extraction (Suwon 213-1, Nongpaik, Jinheung), culm length (Nongpaik, Suwon 213-1), and Auricle distance (Suwon 213-1). The degree of sterility was able to be estimated from the linear regression equation between the degree of panicle extraction (distance from panicle neck to flag leaf) and fertility percentage. In the case of heavy cold damage by the treatment of low temperature at meiotic stage, the rice plant had somewhat lower pollen density per anther, small and ununiform anther and pollen in size, and more sterile pollen grains. Suwon 213-1 showed anthesis in almost all spikelets, while Nongpaik, Jinheung and Hayayuki indicated considerable number of indehisced anther at 5 days after heading. 2. The fertility were not generally higher in cooling treatment at heading stage than at meiotic stage treatment. And significant correlation was found between the percentage of grain fertility treated at above two stages. Nongpaik and Jinheung were not affected in percentage of fertility by 5 day treatment at 15$^{\circ}C$ when these were treated at heading stage. Indehisced anthers were not found in Suwon 213-1 and Hayayuki, but Nongpaik and Jinheung showed more anthers which did not show anthesis 3. There was different varietal response to low temperature which was indicated by the decrease of grain fertility resulted from cooling treatment at meiotic stage. Jaekeun and Jinheung did not show low fertility but Milseong, Suwon 210, Satominoli and Suwon 213-1 showed outstanding decrease in fertility percentage by the cooling treatment at meiotic stage. The varieties which had low fertility were likely to have low pollen density per anther, abnormal anthers, small size po]]en grains and many sterile pollens. 4. Remarkable varietal difference of cold resistance was found in heading stage cooling treatment. Nongpaik, Jinheung, Jaekeun, Paltal, Akibare, Milseung and Palkeong were not affected in grain fertility by cooling treatments but Nonglimna No. 1, Suseong, Hayayuki, Suwon 213-1 and Suwon 210 showed significantly high sterility as treated by cool temperature. Most of the varieties showed higher fertility by cooling treatment at heading stage than meiotic stage but Hayayuki, Suseong and Nonglimna No.1 showed lower fertility when these were treated at heading stage than meiotic stage. There were two grops of varieties in the response to cooling treatment, one was somewhat non-anthesised and the other showed full anthesis. 5. In cold injury test of young seedlings, the result of observation was not accorded with the degree of growth inhibition. As a general, Palkeum and Suseong were highly torelant to cool temperature but Suwon 213-1, Jaekeun, Paltal, Shirogane, Palkeong, Mankyung were highly susceptible. 6. There is no significant correlation between the degree of young seedling cold damage and or the degree of growth retardation at seedling stage and grain fertility resulted from coding treatment both heading and meiotic stage.

• Journal of The Korean Society of Grassland and Forage Science
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• v.33 no.2
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• pp.123-130
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• 2013

This study was conducted to investigate the effects of climate change on the growth characteristics and dry matter yields of silage corn hybrids in fields of forage crops of Hanwoo Experiment Station, National Institute of Animal Science, RDA, from Apr. 2009 to Sep. 2011. Corn hybrids were cultivated in Daegwallyeong of Gangwon Province, at an altitude of 760 m. Corn varieties used in this study consisted of 5 domestic varieties and 5 foreign varieties. Differences of silk days according to years occurred at an average of 5.5 days. The silk periods of domestic varieties occurred from Aug. 8 to 12, while that of overseas varieties was from Aug. 5 to 11. Silk days of domestic varieties occurred approximately 3 to 4 days earlier than those of oversea varieties. Silk days of Kwangpyeongok and P3156 belonging to the early varieties were Aug. 8 and 5, respectively. Kwangpyeongok and P3156 were Aug. 8 and 5, respectively. Pyeonganok and DK729 belonged to late varieties. The mean plant height of corn was approximately 231 cm, while those of Kwangpyeongok and Pyeonganok were 236 cm and 237 cm, respectively. The mean stem diameter and ear height of corn were approximately 23.2 mm and 94 cm, respectively. In the case of stem diameters, those of Cheonganok and 33J56 were 86 cm and 80 cm, respectively, while Gangdaok grew to a greater height (enter height) than other varieties. Dry matter yields of Kwangpyeongok and Pyeonganok were higher than those of other varieties. The mean leaf ratio of corn was 39.3%, while that of domestic varieties increased as compared to foreign varieties. The average DM yield of corn was 16,653 kg/ha, while those of 32P75, P3156, Pyeonganok, P3394 and Kwangpyeongok were 18,901, 17,997, 17,675, 17,194, 17,188 kg/ha, respectively. Total digestible nutrient (TDN) yields of 32P75, P3156, P3394, Pyeonganok and Kwangpyeongok were 13,381, 12,590, 12,532, 12,140 and 12,036 kg/ha, respectively. Corn crude protein (CP), in vitro dry matter digestibility (IVDMD), neutral detergent fiber (NDF), acid detergent fiber (ADF) and TDN were 7.8%, 74.2%, 42.4%, 23.5% and 70.3%, respectively. In the case of nutritive values of corn, there was no significant difference between of corn varieties of domestic and foreign origin.

• Journal of Forest and Environmental Science
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• v.21 no.1
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• pp.34-58
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• 2005

This study was executed to find out how to improve the planting and use of landscaping plants in Weonju and Hoengseong. 1. The number of street trees were 22,068 and the species number were 10 species in Weonju in 2004. The major species of street trees were Ginkgo biloba(58%), Prunus sargentii(15%), Zelkova serrata(9%), Prunus armeniaca var. ansu(8%), and Acer palmatum(6%). The ratio of native species versus exotic were 50:50. In Hoengseong, the number of street trees was 13,500 and the species number were 15 species. The major species of street trees were Prunus sargentii(42%), Ginkgo biloba(23%), Acer triflorum(12%), Prunus armeniaca var. ansu(6%), and Prunus mume(4%). The ratio of native species versus exotic were 67:33. The species of which planting frequency within two areas was very high were Ginkgo biloba and Prunus sargentii. 2. It is necessary to select tree species suitable for the characteristics of the locality and to raise distinctive street trees that contribute to the tourist industry. For the purpose, the appropriate street trees in two areas are Cornus controversa, Quercus aliena, Zelkova serrata, Prunus padus, Sorbus alnifolia, Sorbus comixta, Albizzia julibrissin, Acer triflorum, Styrax japonica, Chionanthus retusus, Celtis sinensis, Prunus yedoensis, Malus sieboldii, Crataegus Pinnatifida, Prunus armeniaca var. ansu and Pyrus pyrifolia etc.. 3. Appropriate pruning adds to the aesthetic and prolongs the useful life, it also requires less managing of insects and diseases to maintain good healthy of street trees. Street trees were not properly pruned due to electric lines and shortage of pruning information. The pruning was controlled by Korea Electric Power Co, which has no pruning information. Pruning must be maintained by a professional landscape company to maintain good shape such as with Bonsai. The shrubs planting zone between street trees and other trees, and preservation plates were established for healthy of street trees. They have to be repaired and maintained well to keep better environmental conditions. The proper fertilization, the control of pests and diseases, the installation of drainpipe and the use of soil brought from another place were needed to improve the planting, use and maintenance of landscape plants. 4. The species number of school trees and flowers of 102 schools in Weonju and Hoengseong were 17species, 16species respectively. The major species of school trees in Weonju were Juniperus chinensis(24%), Ginkgo biloba(17%), Pinus densiflora(14%), Zelkova serrata(14%), and Pinus koraiensis(9%), and those of school trees in Hoengseong were Pinus koraiensis(44%), Abies holophylla(25%), Juniperus chinensis(8%), and Ginkgo biloba(8%). The major species of school flowers in Weonju were Rosa centifolia(47%), Forsythia koreana(24%), Magnolia kobus(12%), and Rhododendron schlippenbachii(6%), and those of school flowers in Hoengseong were Forsythia koreana(36%), Rhododendron schlippenbachii(33%), Magnolia kobus(6%) and Dicentra spectabilis(6%). 5. The species number of the protection trees designated by Woenju and Hoengseong were 15 species. The major species of protection trees were Zelkova serrata(100 trees), Ginkgo biloba(18) Pinus densiflora(7), Quercus spp. (5), Juniperus chinensis(4) and Alnus japonica(4). 6. The landscape plants planted around 2004 in weonju were Prunus yedoensis(2,563 trees), Betula platyphylla var. japonica(2,000), Abies holophylla(1,785), Diospyros kaki(1,100), Prunus sargentii(880) and Prunus armeniaca var. ansu(708) etc.. The shrubs planted were Rhododendron obutusum(21,559 plants), Rosa centifolia (7,150), Rhododendron yedoense var. poukhanense(5,950), Forsythia koreana(3,000) and Ligustrum obtusi[olium(2,500) etc.. The landscape plants planted in Hoengseong Acer triflorum(928trees), Prunus yedoensis(455), Zelkova serrata(327), Thuja orientalis(261), Prunus sargentii(257), Pinus koraiensis(200), Prunus persica for. rubro-plena(200) and Pyrus pyrifolia (200) etc.. The shrubs planted were Rhododendron yedoense var. poukhanense(15,936), Syringa dilatata(10,090), Forsythia koreana(9,660), Cercis chinensis(3,200), Buxus microphylla var. koreana(2,600) and Rosa centifolia(1,868) etc.. 7. The species numbers of the herbaceous plants planted in 2004 in Weonju were 24 species and the ratio of native species versus exotic were 7:17. The major species of perennial plants were Aster koraiensis(30,656 plants), Coreopsis drummondii(7,656), Rudbeckia bicolor(6,000), Chrysanthemum morifolium(4,850) and Chrysanthemum zawadskii var. latilobum(4,312). The major species of annuals and biennials were Cosmos bipinnatus(672,000 plants), Zinnia elegans(35,600), Petunia hybrida(26,920), Viola tricolor(23,000), Helianthus annuus(17,000), and Geranium cinereum var. pubcaulescens(5,200). In Hoengseong, the numbers of herbaceous plants were 906,310 plants and the species numbers were 15 species. The major species of perennials plants were Aster koraiensis(70,480 plants), Hemerocallis fulva(20,070), and Phlox drummondii(18,000). The major species of annuals and biennials were Phlox hybrida(174,000 plants), Cosmos bipinnatus(125,000), Zinnia elegans(109,000), Tagetes patula(96,700), Vinca rosea(89,000) and Calendula officinalis(70,000). 8. Through these result, it was thought that the diversification of planting species, the selection of plants suitable to each space and the generalization of use of native species were needed.

• Journal of the Korean Geotechnical Society
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• v.35 no.5
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• pp.5-19
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• 2019

Considering the natural phenomenon in which steep slopes ($65^{\circ}{\sim}85^{\circ}$) consisting of rock mass remain stable for decades, slopes steeper than 1:0.5 (the standard of slope angle for blast rock) may be applied in geotechnical conditions which are similar to those above at the design and initial construction stages. In the process of analysing the stability of a good to fair continuum rock slope that can be designed as a steep slope, a general method of estimating rock mass strength properties from design practice perspective was required. Practical and genealized engineering methods of determining the properties of a rock mass are important for a good continuum rock slope that can be designed as a steep slope. The Genealized Hoek-Brown (H-B) failure criterion and GSI (Geological Strength Index), which were revised and supplemented by Hoek et al. (2002), were assessed as rock mass characterization systems fully taking into account the effects of discontinuities, and were widely utilized as a method for calculating equivalent Mohr-Coulomb shear strength (balancing the areas) according to stress changes. The concept of calculating equivalent M-C shear strength according to the change of confining stress range was proposed, and on a slope, the equivalent shear strength changes sensitively with changes in the maximum confining stress (${{\sigma}^{\prime}}_{3max}$ or normal stress), making it difficult to use it in practical design. In this study, the method of estimating the strength properties (an iso-angle division method) that can be applied universally within the maximum confining stress range for a good to fair continuum rock mass slope is proposed by applying the H-B failure criterion. In order to assess the validity and applicability of the proposed method of estimating the shear strength (A), the rock slope, which is a study object, was selected as the type of rock (igneous, metamorphic, sedimentary) on the steep slope near the existing working design site. It is compared and analyzed with the equivalent M-C shear strength (balancing the areas) proposed by Hoek. The equivalent M-C shear strength of the balancing the areas method and iso-angle division method was estimated using the RocLab program (geotechnical properties calculation software based on the H-B failure criterion (2002)) by using the basic data of the laboratory rock triaxial compression test at the existing working design site and the face mapping of discontinuities on the rock slope of study area. The calculated equivalent M-C shear strength of the balancing the areas method was interlinked to show very large or small cohesion and internal friction angles (generally, greater than $45^{\circ}$). The equivalent M-C shear strength of the iso-angle division is in-between the equivalent M-C shear properties of the balancing the areas, and the internal friction angles show a range of $30^{\circ}$ to $42^{\circ}$. We compared and analyzed the shear strength (A) of the iso-angle division method at the study area with the shear strength (B) of the existing working design site with similar or the same grade RMR each other. The application of the proposed iso-angle division method was indirectly evaluated through the results of the stability analysis (limit equilibrium analysis and finite element analysis) applied with these the strength properties. The difference between A and B of the shear strength is about 10%. LEM results (in wet condition) showed that Fs (A) = 14.08~58.22 (average 32.9) and Fs (B) = 18.39~60.04 (average 32.2), which were similar in accordance with the same rock types. As a result of FEM, displacement (A) = 0.13~0.65 mm (average 0.27 mm) and displacement (B) = 0.14~1.07 mm (average 0.37 mm). Using the GSI and Hoek-Brown failure criterion, the significant result could be identified in the application evaluation. Therefore, the strength properties of rock mass estimated by the iso-angle division method could be applied with practical shear strength.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.18 no.3
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• pp.211-226
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• 2023

As we transition into the post-COVID era, economic activities that were stagnant are regaining momentum. In particular, there is a growing trend of technology entrepreneurship driven by the opportunities of digital transformation in the Fourth Industrial Revolution. However, entrepreneurship education content is struggling to keep up with the rapid pace of technological change. This study aims to emphasize the importance of entrepreneurship mentoring as a crucial component of entrepreneurship education content that requires adaptation and advancement due to the increasing demand for technology entrepreneurship. This study redefines startup mentoring, which is differentiated from general mentoring, at the present time when the demand for startups, which increases with the declining employment rate, increases, and the development of quality startup education contents and securing professional startup mentors are required. According to the start-up stage, it is divided into preliminary entrepreneurs and early entrepreneurs, and the effect of entrepreneurship knowledge and self-efficacy among start-up mentoring functions on entrepreneurial will and mentoring satisfaction is improved by empirically researching the effects of start-up mentoring functions in the case of initial entrepreneurs as a moderating effect. To confirm the importance of entrepreneurship mentoring effect for. To this end, among the mentoring functions, entrepreneurship knowledge and self-efficacy were set as independent variables, and entrepreneurial will and mentoring satisfaction were set as dependent variables. The research model was designed and hypotheses were established. In addition, empirical analysis was conducted by conducting a questionnaire survey on trainees who received entrepreneurship mentoring education at ICCE Startup School and Opus Startup School. To summarize the results of the empirical analysis, first, among the entrepreneurship mentoring functions, entrepreneurship knowledge and self-efficacy were analyzed to have a significant positive (+) effect on entrepreneurial will. Second, among the entrepreneurship mentoring functions, entrepreneurship knowledge and self-efficacy were analyzed to have a significant positive (+) effect on mentoring satisfaction. Third, it was analyzed that entrepreneurship had no significant moderating effect on entrepreneurial knowledge and entrepreneurial will. Fourth, it was analyzed that entrepreneurship had no significant moderating effect on mentoring satisfaction. Fifth, it was found that entrepreneurship had a significant moderating effect between self-efficacy and will to start a business. As a result of the research analysis, the first implication is that the mentoring function in start-up education is analyzed to produce meaningful results for both the initial entrepreneurs and the prospective entrepreneurs in the will to start a business and satisfaction. . Second, it was analyzed that there was no significant relationship between whether a business was started and the mentoring function and effect. However, it was analyzed that the will to start a business through improvement of self-efficacy through mentoring was significantly related to whether or not to start a business. turned out to be helpful. Many start-up education programs currently conducted in Korea educate both early-stage entrepreneurs and prospective entrepreneurs at the same time for reasons such as convenience. However, through the results of this study, even in small-scale entrepreneurship mentoring, it is suggested that customized mentoring through detailed classification such as whether the mentee has started a business can be a method for successful entrepreneurship and high satisfaction of the mentee.

• Tuberculosis and Respiratory Diseases
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• v.58 no.5
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• pp.498-506
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• 2005

Background : This study compared the bronchodilator efficacy and safety of tiotropium inhalation capsules ($18{\mu}g$ once daily) with a ipratropium metered dose inhaler (2 puffs of $20{\mu}g$ q.i.d.) in patients with chronic obstructive pulmonary disease (COPD). Method : After the initial screening assessment and a two-week run-in period, patients received either tiotropium $18{\mu}g$ once daily or ipratropium $40{\mu}g$ four times daily over a period of 4 weeks in a double blind, double dummy, parallel group study. The outcome measures were the lung function, the daily records of the peak expiratory flow rate (PEFR), the patients' questionnaire, and the use of concomitant salbutamol. The forced expiratory volume in one second ($FEV_1$) and the forced vital capacity (FVC) were measured 5 minutes before inhalation, and 0.5, 1, 2 and 3 hours after inhaling the study drug on days 0, 14 and 28. Result : In 16 centers, 134 patients with a mean (SD) age of 66 (7) years and a predicted $FEV_1$ of 42 (12)% were analyzed. The trough $FEV_1$ response was significantly higher in the tiotropium group than in the ipratropium group after a four-week treatment period. The weekly mean morning PEFR of the tiotropium group was consistently higher than that of the ipratropium group during the 4-week treatment period with differences ranging from 12.52 to 13.88 l/min, which were statistically significant. Tiotropium was well tolerated by the COPD patients during the 4-week treatment period and had a similar safety profile to ipratropium. Conclusion : This study shows that tiotropium administrated once daily has a superior bronchodilator effect with a similar safety profile in treating COPD patients compared with ipratropium, inhaled four times daily.

• Tuberculosis and Respiratory Diseases
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• v.50 no.2
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• pp.182-195
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• 2001

Background : Idiopathic pulmonary fibrosis(IPF) is a devastating illness for which there is little effective treatment. The key cytokines currently implicated in the fibrotic process are the transforming growth factor-${\beta}_1$(TGF-${\beta}_1$), tumor necrosis factor-$\alpha$(TNF-$\alpha$), endothelin-1(ET-1) and interferon-$\gamma$(IFN-$\gamma$). The rat model for paraquat-induced pulmonary fibrosis was chosen to investigate the role of ET-1 in this disease. Both ET-1 and TGF-${\beta}_1$ expression in lung lesions were examined using immunohistochemical staining. After $Bosentan^{(R)}$ administration, an orally active ET-$l_A$ and ET-$1_B$ receptor antagonist, the degree of pulmonary fibrosis and ET-1 and TGF-${\beta}_1$ expression were analyzed. Method : Sprague-Dawley rats were divided into three groups, the control group, the fibrosis group, and the fibrosis-$Bosentan^{(R)}$-treated group. The animals were sacrificed periodically at 1, 3, 5, 7, 10, 14 days after administering saline or paraquat. The effects between groups were compared with the results of light microscopy and immunohistochemical staining for ET-1 and TGF-${\beta}_1$. The degree of fibrosis was evaluated by H&E and Masson's trichrome staining, which were graded by a computerized image analyzer. The degree of immunohistochemical staining was categorized by a semi-quantitative analysis method. Results : The lung collagen content had increased in the paraquat instillated animals by day 3, and continued to increase up to day 14. A daily treatment by gavage with $Bosentan^{(R)}$ (100mg/kg) did not prevent the increase in collagen deposition on the lung that was induced by paraquat instillation. There were increased immunohistochemical stains of ET-1 on the exudate, macrophages, vascular endothelial cells and pneumocytes in the paraquat instillated group. Furthermore, TGF-${\beta}_1$ expression was higher on the exudate, macrophages, some inflammatory cells, pneumocytes( type I, and II), vascular endothelium and the respiratory epithelial cells around the fibrotic area. After Bosentan treatment, there were no definite changes in ET-1 and TGF-${\beta}_1$ expression. Conclusion : Fibrosis of the Paraquat instillated group was more advanced when compared with the control group. In addition, there was increased ET-1 and TGF-${\beta}_1$ expression around the fibrotic area. ET-1 is associated with lung fibrosis but there was little effect of the ET-1 receptor blocker($Bosentan^{(R)}$) on antifibrosis.Background : Idiopathic pulmonary fibrosis(IPF) is a devastating illness for which there is little effective treatment. The key cytokines currently implicated in the fibrotic process are the transforming growth factor-${\beta}_1$(TGF-${\beta}_1$), tumor necrosis factor-$\alpha$(TNF-$\alpha$), endothelin-1(ET-1) and interferon-$\gamma$(IFN-$\gamma$). The rat model for paraquat-induced pulmonary fibrosis was chosen to investigate the role of ET-1 in this disease. Both ET-1 and TGF-${\beta}_1$ expression in lung lesions were examined using immunohistochemical staining. After $Bosentan^{(R)}$ administration, an orally active ET-$1_A$ and ET-$1_B$ receptor antagonist, the degree of pulmonary fibrosis and ET-1 and TGF-${\beta}_1$ expression were analyzed. Method : Sprague-Dawley rats were divided into three groups, the control group, the fibrosis group, and the fibrosis-$Bosentan^{(R)}$-treated group. The animals were sacrificed periodically at 1, 3, 5, 7, 10, 14 days after administering saline or paraquat. The effects between groups were compared with the results of light microscopy and immunohistochemical staining for ET-1 and TGF-${\beta}_1$. The degree of fibrosis was evaluated by H&E and Masson's trichrome staining, which were graded by a computerized image analyzer. The degree of immunohistochemical staining was categorized by a semi-quantitative analysis method. Results : The lung collagen content had increased in the paraquat instillated animals by day 3, and continued to increase up to day 14. A daily treatment by gavage with $Bosentan^{(R)}$ (100mg/kg) did not prevent the increase in collagen deposition on the lung that was induced by paraquat instillation. There were increased immunohistochemical stains of ET-1 on the exudate, macrophages, vascular endothelial cells and pneumocytes in the paraquat instillated group. Furthermore, TGF-${\beta}_1$ expression was higher on the exudate, macrophages, some inflammatory cells, pneumocytes( type I, and II), vascular endothelium and the respiratory epithelial cells around the fibrotic area. After Bosentan treatment, there were no definite changes in ET-1 and TGF-${\beta}_1$ expression. Conclusion : Fibrosis of the Paraquat instillated group was more advanced when compared with the control group. In addition, there was increased ET-1 and TGF-${\beta}_1$ expression around the fibrotic area. ET-1 is associated with lung fibrosis but there was little effect of the ET-1 receptor blocker($Bosentan^{(R)}$) on antifibrosis.