• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.5
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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.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.7 no.1
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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.

• Bulletin of the Society of Naval Architects of Korea
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• v.6 no.1
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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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• v.19 no.6
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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.

• Journal of Food Hygiene and Safety
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• v.22 no.2
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• pp.120-126
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• 2007

Present study have been performed to develop Bulnesia sarmienti as a functional food. Methanol, n-hexane, chloroform, ethyl acetate and butanol extracts of Bulnesia sarmienti contained total phenol by 5.81 to 7.47%. It is high content than fruits which were known as high contests of total phenol. The electron donating ability of the extract of Bulnesia sarmienti were increased along with increasing concentrations of extracts. At $500{\mu}g/mL\;and\;1000{\mu}g/mL$, the all extracts showde more than 80% of scavenging abilities, which means the equal effect of the antioxidant, BHT. Nitrite scavenging abilities were measured as follows: methanol, butanol, 5.53, 5.77% at $100{\mu}g/mL$, respectively. The ethyl acetate extract was 73.29% at $1000{\mu}g/mL$ which showed the highest activity and methanol, butanol, n-hexane, chloroform and water extract were 65.65, 65.02, 47.49, 52.51, 45.54% which also showed relatively high activities. The growth inhibitory effects of each solvent extract on tumor cell were as follows: test against SUN-1, the gastric carcinoma cell, exhibited the highest inhibitory effects at $100{\mu}g/mL$ where the n-hexane extract was 61.6%. The ethyl acetate and water extracts did not revealed any inhibitory effects. Hela, the uterine carcinoma cell, exhibited the highest inhibitory effects at $100{\mu}g/mL$ where the n-hexane extract was 75.1%. The water extracts did not revealed any inhibitory effects. HT-29, the colon carcinoma cell, also exhibited the highest inhibitory effects at $100{\mu}g/mL$ where n-hexane extract was 57.4%. In conclusion, Bulnesia sarmienti have been shown the antioxidant and antitumor effects, and that it is expected to be developed as functional foods.