• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.4
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• pp.527-533
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• 2013

In this study, we established the optimal conditions for obtaining water-soluble extracts with antioxidant activity from Kalopanacis cortex. The extraction conditions tested included cold treatment, extraction time (1, 5, 10, 15, and 24 h), and extraction temperature (55, 75, and $95^{\circ}C$). The highest total polyphenol compound content from water soluble extracts ($612{\mu}g/mL$) was obtained at $95^{\circ}C$ for 15 h after cold treatment. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenger activity was also highest (78.8%) under these conditions, which was comparable to 70.2% of ascorbic acid. The hydroxyl radical scavenging activity (HRSA) was also highest (69.0%) under these conditions, stronger than 56.6% of ascorbic acid. These results may provide critical evidence supporting the use of Kalopanacis cortex as a source of antioxidants in functional foods.

• Nutrition Research and Practice
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• v.1 no.3
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• pp.189-194
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• 2007

This study investigated in vitro antioxidant activity of Sonchus oleraceus L. by extraction solvent, which were examined by reducing power, hydroxyl radical-scavenging activity(HRSA) and 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assays. 70% MeOH extract had the greatest reducing power while EtOH extract had the greatest HRSA. The antioxidant activity of S. oleraceus extracts was concentration dependent and its $IC_{50}$ values ranged from 47.1 to $210.5\;{\mu}g/ml$ and $IC_{50}$ of 70% MeOH, boiling water and 70% EtOH extracts were 47.1, 52.7 and $56.5\;{\mu}g/ml$, respectively. 70% MeOH extract of S. oleraceus contained the greatest amount of both phenolic and flavonoid contents. The extracts tested had greater nitrite scavenging effects at lower pH conditions. The cytotoxic activity showed that EtOH extract had the best activity against the growth of stomach cancer cell. These results suggest that S. oleraceus extract could be used as a potential source of natural antioxidants.

• Food Engineering Progress
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• v.21 no.3
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• pp.292-298
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• 2017

The aim of this study was to evaluate the effects of microencapsulation on the water absorption, DPPH radical scavenging activity (DRSA), hydroxyl radical scavenging activity (HRSA) and tyrosinase inhibition activity (TIA) in corn silk extracts. The lowest value (0.20) of water absorption index (WAI) and the highest value (95.23%) of water solubility index (WSI) were maltodextrin+cyclodextrin microencapulated corn silk extracts (MD+CD) and cyclodextrin encapulated corn silk extracts (CD), respectively. The 18.60% for DRSA value of control was increased to 89.25% for that of CD. The 16.89% for HRSA value of control was increased to 47.46%, and 7.16% for TIA value of control was increased to 39.35% for that of MD+CD, respectively. The MD+CD would be used for functional food and cosmetics materials as antioxidant and skin whitening agents. All investigated responses between control and treatment were statistically significant (p<0.05).

• Korean Journal of Materials Research
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• v.27 no.12
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• pp.716-721
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• 2017

SiAlON-based ceramics are some of the most typical ceramic materials used as cutting tools for HRSA(Heat Resistant Super-Alloys). SiAlON can be fabricated using ceramic processing, such as mixing, granulation, compaction, and sintering. Spray drying is a widely-used method for producing a granular powder of controlled morphology and size with flowability. In this study, we report a systematic investigation aimed at optimizing spherical granule morphology by controlling spray-drying parameters such as gas flow and feed rate. Before spray drying, the viscosities of the raw material slurries were also optimized with the amount of dispersant added.

• Journal of Powder Materials
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• v.26 no.5
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• pp.415-420
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• 2019

SiAlON ceramics are used as ceramic cutting tools for heat-resistant super alloys (HRSAs) due to their excellent fracture toughness and thermal properties. They are manufactured from nitride and oxide raw materials. Mixtures of nitrides and oxides are densified via liquid phase sintering by using gas pressure sintering. Rare earth oxides, when used as sintering additives, affect the color and mechanical properties of SiAlON. Moreover, these sintering additives influence the cutting performance. In this study, we have prepared $Yb_{m/3}Si_{12-(m+n)}Al_{m+n}O_nN_{16-n}$ (m = 0.5; n = 0.5, 1.0) ceramics and manufactured SiAlON ceramics, which resulted in different colors. In addition, the characteristics of the sintered SiAlON ceramics such as fracture toughness and microstructure have been investigated and results of the cutting test have been analyzed.

• Journal of Powder Materials
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• v.24 no.6
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• pp.431-436
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• 2017

SiAlON-based ceramics are some of the most typical oxynitride ceramic materials, which can be used as cutting tools for heat-resistant super-alloys (HRSA). SiAlON can be fabricated by using gas-pressure reactive sintering from the raw materials, nitrides and oxides such as $Si_3N_4$, AlN, $Al_2O_3$, and $Yb_2O_3$. In this study, we fabricate $Yb_{m/3}Si_{12-(m+n)}Al_{m+n}O_nN_{16-n}$ (m=0.3, n=1.9, 2.3, 2.7) ceramics by using gas-pressure sintering at different sintering temperatures. Then, the densification behavior, phase formation, microstructure, and hardness of the sintered specimens are characterized. We obtain a fully densified specimen with ${\beta}$-SiAlON after gas-pressure sintering at $1820^{\circ}C$ for 90 min. under 10 atm $N_2$ pressure. These SiAlON ceramic materials exhibited hardness values of ~92.9 HRA. The potential of these SiAlON ceramics for cutting tool application is also discussed.

• Sleep Medicine and Psychophysiology
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• v.4 no.1
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• pp.107-119
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• 1997

Objectives: The psychophysiologic response pattern between healthy subjects and patients with generalized anxiety disorder, and the relationship among anxiety rating scales and those patterns in patients were examined. Methods: Twenty-three patients with generalized anxiety disorder(AD) and 23 healthy subjects were evaluated by Hamilton Rating Scale for Anxiety(HRSA) and State-Trait Anxiety Inventory before baseline stressful tasks. Subjective Units of Distress were evaluated just before baseline period, immediately after stressful tasks, at the end of the entire procedure, and psychophysiologic measures, i.e., skin temperature(ST), electromyographic activity(EMG), heart rate(HR), electrodermal response(EDR) during baseline & rest and during two psychologically stressful tasks (mental arithmetic, TM; talk about a stressful event, TT) were also evaluated. Results: 1) AD group showed significantly higher EMG level during rest after stressful tasks and higher HR level during all period except TM compared to control group. 2) AD group showed lower change in the startle response(SR) of ST, in the SR & the recovery response(RR) of EMG during TM, and in the RR of EDR immediately after TM than control group. AD group showed that the RR of EDR was significantly lower than the SR during stressful tasks. 3) We found that there was significantly negative correlation between state anxiety and the RR of EDR after TT in AD group. We also found that there were significantly positive correlations between HRSA score and the SRs of EDR during stressful tasks, and between state anxiety and the SR of EDR during TT. Conclusion: Our results suggest that patients with generalized anxiety disorder show higher autonomic arousal than healthy subjects and decreased physiologic flexibility or reduced autonomic flexibility.

• Korean Journal of Veterinary Service
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• v.37 no.2
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• pp.111-122
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• 2014

The present study was designed to explore the antioxidant effect of Bamboo powder and its immunoreactivity in pigs. We investigated the functional properties of Bamboo extracts by means of measuring the contents of total polyphenols and flavonoid as well as determining ABST, DPPH radical scavenging activity, and hydroxyl radical scavenging activity and anticancer activity. The total phenolic compound and flavonoids contents of Bamboo extracts were 171.25 mg/g and 127.5 mg/g, respectively. The DPPH radical, hydroxyl radical, ABST radical scavenging activity of Bamboo extracts were 17.3%, 12.5% and 21.5%, respectively. Evidenced by MTT and cell cycle assay, Bamboo dose-dependently inhibited the cell proliferation and induced G0/G1-phase arrest in CHO cells at concentrations of 100, 250, and 500 ${\mu}g/ml$ Bamboo extracts. More than 80% of apoptotic cells were observed by staining with annexin V in 500 ${\mu}g/ml$ Bamboo-treated CHO cells, indicating that Bamboo had potent anticancer activities. Next, to investigate the effect of Bamboo on cytokine, immunoglobulin concentration, and blood compositions, flatting pigs were fed with Bamboo powder for 38 days. Flatting pigs were divided into 4 groups; basal diet (control), basal diet supplemented with 1% Bamboo powder (T1), 2% Bamboo powder (T2), and 3% Bamboo powder (T3). The level of hemoglobin increased in the all Bamboo-fed groups compared with the normal control group. In particular, platelet levels in the all Bamboo-treated groups increased by approximately 90% compared with the levels from pig on a normal control. Serum levels of immunoglobulins (IgG, IgA) in the pigs fed Bamboo powder were modestly increased, and the interferon-${\gamma}$ level also was strongly increased in 2% or 3% Bamboo-fed groups compared with the levels in control groups. Together, these results demonstrated that Bamboo extracts had an effective capacity of scavenging for ABTS, DPPH, and hydroxyl radicals and showed correlation with potent phenol and flavonoid contents, thus suggesting its antioxidant potential. Moreover, administration of Bamboo in 2~3% improved blood parameters and platelets, and especially immunity-related ones such as IgG, IgA, and interferon-${\gamma}$, leading to be potential feed additives in flatting pigs.