• 한국수산과학회지
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• 제42권5호
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• pp.434-441
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• 2009

This study was conducted to compare the biological activities of 7 melania snails from the family Pleuroceridae (Semisulcospira coreana, Koreanomelania nodifila, Semisulcospira forticosta, Koreoleptoxis globus ovalis, Semisulcospira libertina, Semisulcospira tegulata and Semisulcospira gottschei) in Korea. Among the 7 species, S. coreana, Korean. nodifila, S. forticosta and S. gottschei showed over 80% cytotoxicities on three cancer cell lines (SNU-1, A549 and Hep 3B) compared to the non-treatment, whereas S. libertina and S. tegulata showed almost no growth inhibition activities on the same cancer cell lines. In relation to ACE inhibition activity, only S. coreana, Korean. nodifila, and S. forticosta showed over 60% ACE inhibition activities, whereas other melania snails exhibited inhibition activities of lower than 25%. DPPH radical scavenging activities were also determined, and used to categories melania snails into three groups based on Duncan's multiple range test at P<0.05. The amount of TNF-${\alpha}$ produced by in vitro mouse peritoneal macrophage was determined according to bioactivity on L-929 cells. Three melania snails, S. coreana, Korean. nodifila and S. gottschei, exhibited 95.2%, 89.7% and 93.7% cell death(%) on L-929 cells, respectively. Glucose-6-phosphate dehydrogenase inhibitory activity was also obtained in the extract of S. coreana (31.9%) and Korean. nodifila (28.1%), showing that these extracts can be used as supplemental dietary health foods. In conclusion, we believe that the extracts of melania snails should be given due consideration in functional health food development.

• 한국산업보건학회지
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• 제7권1호
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• pp.33-48
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• 1997

Korean diffusive sampler (KDS) and charcoal tube (CT) were used for sampling n-hexane, trichloroethylene and toluene in air KDS was made by Department of Environmental Health, SNU-SPH in 1995. Surveys were conducted at ten industrial plants with organic solvents. The relationship between two sampling methods was examined by linear regression analysis, and concentrations by two sampling methods were compared using paired t-test. The results are as follows: 1. The geometric means by CT and KDS methods were 3.26ppm and 3.32ppm for n-hexane, 5.07ppm and 6.34ppm for toluene, and 7.18ppm and 7.90ppm for toluene, respectively. There was no significant difference between results by CT and KDS methods in three organic vapors (p>0.05). When linear regression analysis was performed, two sampling methods were highly related ; correlation coefficients were 0.98, 0.90 and 0.96 for n-hexane, toluene and trichloroethylene, respectively. 2. Airborne concentrations of n-hexane (n=21) were below 0.5 TLV level. The GM by two methods were almost same (3.09 ppm). And there was no significant difference between results by two methods (p>0.05). 3. Since toluene and trichloroethylene concentrations showed several levels, appropriate sampling rates were applied for each level. The GM of toluene concentrations by two methods at 0.5 TLV level were 3.75ppm and 5.48ppm. The KDS method overestimated the toluene concentrations at 0.5 TLV level (p<0.05). The GM values of toluene concentrations at 1 TLV level were 31.80ppm and 25.38ppm and at 2 TLV level were 64.13 ppm and 51.37 ppm. The KDS method underestimated concentration at both level (p<0.05). For trichloroethylene, the GM at 0.5 TLV level were 4.97 ppm and 7.11ppm. The KDS method overestimated the concentration of trichloroethylene (p<0.05). In conclusion, concentrations of three organic vapors measured by CT and KDS were not significantly different and results by two methods were highly related. But at contain concentrations, the levels by method were significantly different. Therefore, it is suggested that sampling rate of KDS should be studied simultaneously using CT method for organic vapors.

• 대한조선학회지
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• 제6권1호
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• pp.25-34
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• 1969

From viewpoints of over-all ship economy the straight framed V-bottom hull forms with chines are considered to be attractive even for usual commercial vessels, because increments of resistance over that of round hull forms, if any, can be well compensated with reduction in construction cost.[1] To investigate the influences of both prismatic coefficient and chine elevation on resistance performance, three models of straight-framed V-bottom hull forms which are similar to Prof. C. Ridgely-Nevitt's W-18, W-8, and W-20[2],[3] in size and hull form coefficients were tested at the SNU Ship Model Towing Tank for resistance measurements. They are of Cp=0.60, 0.65 and 0.70 and of ${\Delta}/(0.01L)^3=300$. Influence of variation of chine elevation on resistance performance were observed with the test results obtained at normal condition, and at the trimed by the stern by 2% and 4% of $L_{bp}$ at normal condition under same displacement. The hull form characteristics are shown in Table 1, and in Fig. 1, 2, 3, 4 and 5. The test results are shown in Fig 8, 9 and 10 in the form of Cr vs. $V/\sqrt{L}$ curves taking Cp as a parameter for normal condition, trim by the stern in 2% and 4% $L_{bp}$ at normal condition , respectively. Cr vs. $V/\sqrt{L}$ curves taking trim condition as a parameter are also shown in Fig 11, 12 and 13 for Cp=0.60 and 0.70, respectively. The best and the worst trim condition at given $V/\sqrt{L}$ in viewpoint of Cr are plotted for each Cp-value as shown in Fig 14, 15 and 16. From the above results the following conclusions are derived: (1) In general, the resistance performance of the straight-framed V-bottom hull forms are not inferior to those of round hull forms. At a certain range of $V/\sqrt{L}$ the former gives less resistance than the latter. (2) Regarding influences of Cp on Cr, it is observed that, at $V/\sqrt{L}$ less than about 0.925, the greater Cp-value gives the more increment of Cr, and that, at $V/\sqrt{L}$ greater than about 0.925 the smaller Cp-value gives the more increment of Cr. It is also noteworthy that the model of Cp=0.70 has remarkable hump on Cr vs. $V/\sqrt{L}$ curve between $V/\sqrt{L}=0.80$ and 0.90. (3) For higher speed within the test range, the chine elevation having the steeper slope around bow and the easier slope around amidship and stern, refered to watering, give the better results in resistance performance. (4) Assuming the chine elevations adopted for the tested models were not of the best, we would expect further improvement of resistance performance for such form. Hence, a systematic study on chine elevation is very disirable to prepare design data of general purpose for the such hull forms.

• Korean Journal of Radiology
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• 제19권6호
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• pp.1119-1129
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• 2018

Objective: To compare the image quality of low-tube-voltage and low-iodine-concentration-contrast-medium (LVLC) computed tomography urography (CTU) with iterative reconstruction (IR) with that of conventional CTU. Materials and Methods: This prospective, multi-institutional, randomized controlled trial was performed at 16 hospitals using CT scanners from various vendors. Patients were randomly assigned to the following groups: 1) the LVLC-CTU (80 kVp and 240 mgI/mL) with IR group and 2) the conventional CTU (120 kVp and 350 mgI/mL) with filtered-back projection group. The overall diagnostic acceptability, sharpness, and noise were assessed. Additionally, the mean attenuation, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and figure of merit (FOM) in the urinary tract were evaluated. Results: The study included 299 patients (LVLC-CTU group: 150 patients; conventional CTU group: 149 patients). The LVLC-CTU group had a significantly lower effective radiation dose ($5.73{\pm}4.04$ vs. $8.43{\pm}4.38mSv$) compared to the conventional CTU group. LVLC-CTU showed at least standard diagnostic acceptability (score ${\geq}3$), but it was non-inferior when compared to conventional CTU. The mean attenuation value, mean SNR, CNR, and FOM in all pre-defined segments of the urinary tract were significantly higher in the LVLC-CTU group than in the conventional CTU group. Conclusion: The diagnostic acceptability and quantitative image quality of LVLC-CTU with IR are not inferior to those of conventional CTU. Additionally, LVLC-CTU with IR is beneficial because both radiation exposure and total iodine load are reduced.

• 한국식품위생안전성학회지
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• 제22권2호
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• pp.120-126
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• 2007

이 연구에서는 Bulnesia sarmienti의 기능성 식품으로서의 이용성을 증대시키기 위하여 각 용매별 분획추출물의 항산화 효과와 MTT검색법을 사용한 항암 효과를 측정하였다. 총 페놀 함량은 methanol, n-hexane, chloroform, ethyl acetate, butanol, 물 추출물에서 각각 6.85, 5.81, 6.30, 7.47, 6.48, 4.82%로 나타났다. 용매분획별 총 페놀 함량은 ethyl acetate추출물에서 가장 높게 나왔고, 비교적 총 페놀 함량이 높은$(0.10{\sim}4.55%)$ 과일류보다도 더 높았다. 전자공여능은 모든 용매추출물에서 농도가 높을수록 그 효과가 증가하였으며 $500{\mu}g/mL\;1000{\mu}g/mL$에서는 모든 추출물에서 80%이상의 높은 소거능을 보여 합성항산 화제인 BHT와 동등한 효과를 보였다. 아질산염 소거능 측정결과, $100{\mu}g/mL$에서 methanol, butanol, ethyl acetate, n-hexean, chloroform, 물 추출물은 각각 4.43, 12.55, 16.72, 1.86, 5.53, 5.77%로 낮은 활성이 나타났다. $500{\mu}g/mL$에서 methanol, butanol, ethyl acetate, n-hexean, chloroform, 물 추출물은 38.52, 33.39, 47.41, 21.17, 31.74, 18.02%로 $100{\mu}g/mL$에서보다 활성이 증가하였고, $1000{\mu}g/mL$에서는 ethyl acetate추출물이 73.29%로 가장 높은 활성을 나타내었다. Methanol, butanol, n-hexean, chloroform, 물 추출물은 각각 65.65, 65.02, 47.49, 52.51, 45.54%로 비교적 높은 활성을 보였다. 추출용매에 따른 암세포의 성장억제효과를 보면 위암세포인 SNU-1은 $100{\mu}g/mL$에서 n-hexane추출물이 61.6%로 가장 높은 억제효과를 나타내었고, ethyl acetate 와 물 추출물은 억제효과가 없었다. 자궁암세포인 Hela는 $100{\mu}g/mL$에서 n-hexane추출물이 75.1%로 가장 높은 억제효과를 나타내었고, 물 추출물은 억제효과가 없었다. 대장암세포인 HT-29도 $100{\mu}g/mL$에서 n-hexane추출물이 57.4%로 가장 높은 억제효과를 나타내었다. 이상의 결과를 종합해 보면, Bulnesia sarmienti는 항산화 및 항암효과가 있는 것으로 판단되며 기능성 식품으로서의 개발가능성을 기대할 수 있을 것으로 생각된다.