• Proceedings of the Korean Society For Composite Materials Conference
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• 1999.11a
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• pp.88-94
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• 1999

Recently, PTFE-polyimide composites are being used self-lubricating parts for industrial field. Thus, this study is mainly concerned with friction and wear properties for the piston ring of non-lubricating air compressor which made of PTFE-polyimide composites. The friction and wear test was carried out for the different composition ratio under the atmosphere room temperature and constant load of 7.69N and their friction and wear properties were compared with each other at various sliding speed. Notable results are summarized as follows. PTFE 100% showed that friction coefficient was almost same values at 0.94 and 1.88m/s but the value was decreased at 2.83m/s because the friction temperature is higher than low speed. PTFE 80%-PI 20% showed the lowest mean friction coefficient at 2.83m/s. PTFE 20%-PI 80% showed the highest friction coefficient at 0.94m/s and the value was decreased at high speed but the value is higher than other materials except PTFE 100 %. PI 100% showed the highest friction coefficient at 0.94 and 1.88m/s because adhesive wear mainly occurred that speed. PTFE 100% showed highest specific wear rate on the whole. Specific wear rate of PTFE 80%-PI 20% was almost the same value with PTFE 20%-PI 80%. PI 100% showed the lowest value at high sliding speed because the friction surface was thicken and carbonated by high friction temperature.

• Korean Journal of Exercise Nutrition
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• v.25 no.4
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• pp.45-53
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• 2021

[Purpose] In this study, we investigated whether a 70% ethanolic (EtOH) extract of Sargassum horneri had antioxidant and anti-inflammatory effects in lipopolysaccharide (LPS)-stimulated macrophage-like RAW 264.7 cells. [Methods] The proximate composition, fatty acids, amino acids, and dietary fiber of S. horneri, various biologically active compounds, and antioxidant activity were analyzed. [Results] The DPPH and ABTS free radical scavenging activities, as well as the reduction power, of the S. horneri extract used here were significantly increased in a concentration-dependent manner. This indicates that S. horneri contains bioactive compounds, such as phenols and flavonoids, that have excellent antioxidant activity. The cellular viability and metabolic activity results confirmed that the extract had no discernible toxicity at concentrations up to 100 ㎍/mL. The levels of nitrites and cytokines (PGE₂, TNF-α and IL-6), which mediate pro-inflammatory effect, were significantly inhibited by treatment with either 50 or 100 ㎍/mL S. horneri extract, whereas that of IL-1β was significantly inhibited by treatment with 100 ㎍/mL of the extract. Similarly, the expression of iNOS and COX-2 proteins also decreased according to 50 or 100 ㎍/mL extract concentrations. NF-κB binding to DNA was also significantly inhibited by treatment with 100 ㎍/mL of extract. [Conclusion] These results suggest that 70% EtOH extracts of S. horneri can relieve inflammation caused by disease or high intensity exercise.

• Food Science of Animal Resources
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• v.37 no.6
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• pp.799-803
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• 2017

In the present study, centrifugation and filtration pretreatments were evaluated to decrease sample preparation time and to improve the sensitivity and specificity of multiplex polymerase chain reaction (PCR) for the detection of low levels of pathogenic Escherichia coli in various foods. Pathogenic E. coli (E. coli NCCP11142, E. coli NCCP14037, E. coli NCCP 14038, E. coli NCCP14039, and E. coli NCCP15661) was inoculated into pork, beef, and baby leafy vegetables at 1, 2, and 3 Log CFU/g. The samples were shaken 30 times (control), then centrifuged or filtered. DNA extracts from the samples were subjected to PCR using the $Powerchek^{TM}$ Diarrheal E. coli 8-plex Detection Kit. In the pork samples, no E. coli was detected in the control samples, while E. coli were detected in 100% of 3-Log CFU/g inoculated and centrifuged samples, and in 100% of 2 and 3-Log CFU/g inoculated, and filtered samples. In the beef samples, all control samples appeared to be E. coli-negative, while E. coli was detected in 50-75% of centrifuged samples, regardless of inoculated level, and in 100% of 2 and 3-Log CFU/g inoculated, and filtered samples. In baby leafy vegetables, E. coli were not detected in 25-50% of the control samples, while E. coli were detected in 0-25% of the centrifuged samples, and 75-100% of the filtered samples, depending on the inoculum amount. In conclusion, filtration pretreatment can be used to minimize sample preparation time, and improve the sensitivity and specificity of rapid detection of pathogenic E. coli in various foods.

• Applied Biological Chemistry
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• v.38 no.5
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• pp.468-472
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• 1995

Substantial amount of caryophyllene oxide (CPO) is present in the essential oils of traditionally-used folk medicinal plants and herbal spices. The CPO, produced via chemical and/or enzymatic reaction of caryophyllene (CP), has largely being used as a flavoring component and exhibited a variety of biological activities. Now, we report the antimutagenic activity of CPO determined by Ames's preincubation test. S-9 fraction was prepared from the liver of rats treated with Arochor 1254. Anatoxin $B_1\;(AFB_1)$ and 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) were used as mutagens. Reduction of mutagenicity of $AFB_1$ or IQ for S. typhimurium TA98 and TA100 by CPO was found to be a dose-dependant manner. CPO (500 ${\mu}g/plate$) reduced mutagenicity of AEB1 for S. typhimurium TA98 and TA100 to 89% and 71%, respectively. For IQ, similar results were observed against S. typhimurium TA98 and TA100, resulting in the inhibition percentage of 77% and 51%, respectively. CP also reduced mutagenicity of AEB1 and IQ for S. typhimurium TA98 and TA100, but the reduction rate was somewhat lowered relative to that of CPO. These results indicate that CPO could be developed as a potent antimutagenic flavoring agent.

• Korean Journal of Applied Biomechanics
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• v.17 no.3
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• pp.31-39
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• 2007

The purpose of this study was to observe the kinematic pattern of elite women 100m hurdler race from start to finish and analyze how the change of horizontal velocity makes an influence on the athletes' performance. The analysis was based on the performance of Korean elite 100m hurdler A and international elite hurdlers B and C. Following results were drawn from the analyzation of elite 100m hurdlers' technical characteristics; During the race, hurdler A made more than 8 m/s of horizontal velocity at the 3rd, 4th, 6th, and the 7th hurdle. The horizontal velocity peaked at the 4th hurdle with 8.23 m/s. On the other hand, hurdler B and hurdler C maintained more than 8 m/s of horizontal velocity from the 2nd hurdle through the 10th hurdle. Hurdler B's fastest horizontal velocity was 8.67 m/s from the 6th to the 7th hurdle and hurdler C's fastest horizontal velocity was 8.85 m/s from the 5th to the 8th hurdle. From the start line to the 3rd hurdle, the times achieved by hurdlers A, B, and C were 4.90 sec, 4.65 sec, and 4.52 sec. In the middle of the race, which is from the 4th hurdle to the 7th hurdle, hurdlers A, B, and C ran in 9.10 sec, 8.60 sec, and 8.38 sec. And the latter part of the race to the 10th hurdle, the times hurdlers A, B, and C hit were 12.32 sec, 11.66 sec, and 11.32 sec. To the finish line, it took 1.15 sec for hurdler A, 1.1 sec for B, and 1.06 sec for C. Hence, to set the record of sub-13 sec, hurdler A should improve her acceleration from the start line to the 1st hurdle with the speed more than 5.4 m/s and should maintain more than 8 m/s of horizontal velocity from the 2nd hurdle through the 10th hurdle. In addition, hurdler A should improve her speed endurance to minimize the deceleration of horizontal velocity from the 4th hurdle to the final hurdle. If hurdler A could shorten 0.05 sec of time in each hurdle section, she would be able to set the record under 13 seconds.

• Journal of Haehwa Medicine
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• v.13 no.2
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• pp.259-265
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• 2004

Objective; This study was designed to investigate the effect of Sa-am acupuncture and Arctii Fructus water extract on Post-herpetic Neuralgia. Method: We have treated them with acupuncture treatment of Sa-am acupuncture and Arctii Fructus water extract and evaluated the effect by Pain Rating Score(P.R.S.) and Visual Analogue Scale(V.A.S.) scale. Result: Before theraphy, the grades of Song's scale were P.R.S. 80 and V.A.S. 100, Kim's sclae's P.R.S. 77 and V.A.S. 100. After theraphy, the grades of song's scale were P.R.S. 5 and V.A.S. 10, Kim's scales's P.R.S. 10 and V.A.S. 10 Conclusion: The treatment of Sa-am-acupuncture and Arctii Fructus water extract on Post-herpetic Neuralgia was effective and will be attempted to the patients with it.

• Journal of People, Plants, and Environment
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• v.24 no.6
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• pp.609-617
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• 2021

Background and objective: The nanobubbles remain stable in water, and it increased dissolved oxygen (DO) in the water that promotes the seed germination and the plant growth. We evaluated the seed germination and growth of sprouts (radish, wheat, and barley) and leafy vegetables (red mustard and pak choi) when irrigated with various DO of nanobubble water (NB). Methods: The oxygen NB was generated by surface friction and treated in 4 levels: NB 0% (control, DO 9.21 mg·L^-1), NB 20% (DO 15.40 mg·L^-1), NB 33% (DO 20.93 mg·L^-1), and NB 100% (DO 39.29 mg·L^-1). Results: The root length of radish and wheat increased more in NB 33% than the control plot. The fresh weight increased in NB 33% compared to the control plot in radish and wheat, and both fresh and dry weight increased more in NB 20%, NB 33%, and NB 100% than the control plot of barley. The leaf length and width of red mustard decreased more in NB 33% and NB 100% than the control plot and NB 20%, which indicated the leaf compactness. The fresh and dry weight of shoot and root increased more in NB 100% than the control plot in red mustard. In pak choi, the shoot fresh weight increased more in NB 100% than the control plot. In leafy vegetables, the germination rate of red mustard in NB 100% was higher than the control plot, however, it was not significantly different between oxygen NB plots in sprout vegetables. Conclusion: The results showed that the root growth and biomass increased after applying NB 33% in sprout vegetables. The leaf growth properties as the number of leaves and leaf size were not significantly different or decreased in NB treatments compared to control plots, but NB 100% (DO 39.29 mg·L^-1) effectively increased the root growth and plant biomass in leafy vegetables.

• Korean Journal of Applied Biomechanics
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• v.17 no.4
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• pp.149-156
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• 2007

The purpose of this study was to compare the world class women's hurdlers with kinematic variables Lee Yeon-Kyoung's in the 100m hurdle. Among korea elite female hurdler, Lee Yeon-Kyoung was participated as a subject. Eight JVC video cameras(GR-HD1KR) were used to film the performance of Lee Yeon-Kyoung at a frame rate of 60fields/s. The real-life three-dimensional coordinate data of digitized body landmarks were smoothed using a fourth order Butterworth low pass recursive digital filter with an estimated optimum cutoff frequency of 7.4Hz. After analyzing and comparing Lee Yeon Kyung's kinematic variables with the world top class hurdlers in the woman's 100m hurdle run, the following conclusions were obtained. 1. Lee should be able to increase the speed with over 5.4m/s from start to first hurdle and then maintain the speed range from 8.33m/s to 8.67m/s until 10th hurdle. Lee should have to maintain the speed with 8.51m/s from 10th hurdle to finish line. 2. Lee has to reach her maximum running speed at 5th hurdle and then has to shorten running time with 0.5sec between hurdles. 3. Lee should be able to run around 2.5sec from start to frist hurdle and then maintain under 1.00sec following phases. Lee should be able to maintain under 1.10sec from 10th hurdle to finish line. 4. Lee needs to control a consistent takeoff and landing distance pattern, Lee needs to lower the height of the center of gravity of the body with 0.33m when she clears the hurdles.

• Asian Journal of Turfgrass Science
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• v.26 no.2
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• pp.110-115
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• 2012

Soil amendments have been used to improve the physical and chemical condition of turf soil, which might optimize turfgrass growth in golf courses. This study was to investigate the effect of inorganic soil amendment (ZC) established in USGA root zone system on growth of creeping bentgrass, cv. 'Penncross' carried out from May to Dec. in 2005 at the nursery on Sinwon Golf Course. To analyze the effects of inorganic soil amendment on pH, specific gravity, infiltration rate, water content, soil hardness, root length, tiller density and dry weight were measured. pH was 6.7-6.8, specific gravity of sand (S) 100% was 1.48 heavier than the other treatments (1.28-1.38). Infiltration rate with ZC 15% + peat moss (P) 5% + S 80% and ZC 10% + S 90% was faster than S 100%. Soil hardness of S 100% was the highest. Root length of creeping bentgrass of P 10% + S 90% (8.6-12.0 cm) was the longest. Tiller density with P 5% + S 95% was more 4-7 ea than other treatments in summer season. In growing season, however, ZC 10% + P 5% + S 85% was more 2-3 ea than others. Dry weight of creeping bentgrass treated by ZC 10% + P 5% + S 85% in summer season and P 5% + S 95% in growing season were heavier than other treatments. It is recommended to combine 5-15% inorganic soil amendment and peat moss 5% with sand in order to sustain soil balance.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.1
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• pp.1-8
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• 2005

Color vision of color vision deficiency is possible using Color space's conversion of color image. Color vision of the RG-Color vision deficiency is possible by the case to maximize the G channel(+100), the case to minimize the G channel(-100), the case to maximize the R channel(+100), the case to convert the R channel to the yellow(Y) channel that is the value of $(-)b^*$ coordinate in CIE $L^*a^*b^*$ color space, the case to separate with only the B channel and the G channel and to appear by the light and darkness difference again, and the case to receive the image only by the light and darkness after separation of saturation and conversion of RGB channel.