• Proceedings of the Materials Research Society of Korea Conference
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• 2011.10a
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• pp.36.2-36.2
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• 2011

Titanium and its alloys have been widely used for orthopedic implants because of their good biocompatibility. We have previously shown that the crystalline titania layers formed on the surface of titanium metal via anodic oxidation can induce apatite formation in simulated body fluid, whereas amorphous titania layers do not possess apatite-forming ability. In this study, hot water and heat treatments were applied to transform the titania layers from an amorphous structure into a crystalline structure after titanium metal had been anodized in acetic acid solution. The apatite-forming ability of titania layers subjected to the above treatments in simulated body fluid was investigated. The XRD and SEM results indicated hot water and/or heat treatment could greatly transform the crystal structure of titania layers from an amorphous structure into anatase, or a mixture of anatase and rutile.The abundance of Ti-OH groups formed by hot water treatment could contribute to apatite formation on the surface of titanium metals, and subsequent heat treatment would enhance the bond strength between the apatite layers and the titanium substrates. Thus, bioactive titanium metals could be prepared via anodic oxidation and subsequent hot water and heat treatment that would be suitable for applications under load-bearing conditions.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.2
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• pp.255-261
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• 2004

Antioxidant activity of extracts from the submerged-liquid culture of mushrooms was measured using two systems : linoleic acid and mouse liver microsomes induced by various free radical sources. Mushrooms of Pleurotus ostreatus (Neutari), Phellinus linteus (Sanghwang), Paecilomyces japonicus (Dongchunghacho), Hericicum erinacium (Norugungdengyee) and Agaricus blazei (Shinryeong) in 1% mulberry tree powder-supplemented medium were incubated in a shaking incubator (200 rpm, $25^{\circ}C$) for 3 days. Hot water extracts of mycelial cultures were freeze-dried, followed by fractioning with hexane, chloroform, ethylacetate and butanol in the order. Antioxidant activity of each sample was examined in free radical-induced linoleic acid oxidation in phosphate-buffered saline (PBS ) solution by measuring the amount of malonaldehyde (MA), and mouse liver microsomal systems by measuring the amount of thiobarbituric acid reactive substances (TBARS). In linoleic acid oxidation system, hot water extracts from the cultures of Pleurotus ostreatus, Phellinus linteus, and Paecilomyces japonicus exhibited stronger antioxidant activity than aqueous or butanol fraction and the combined fraction of hexane, chloroform and ethylacetate, but the hot water extract from Pleurotus ostreatus culture was the strongest activity. The antioxidant activity of the hot water extract from Pleurotus ostreatus culture was stronger than any other fractions in mouse microsomal system. These results suggest that hot water extract of Pleurotus ostreatus culture, and the cultures of Phellinus linteus and Paecilomyces japonicus could be useful for functional materials to reduce the oxidation of lipids in food systems induced by free radicals.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.7
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• pp.609-614
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• 2002

In this study, we investigated the effects of hot water on the aging of URD power cables due to the hot water ingress to power distribution lines. Hot water contacted and non-contacted cables extracted from 2 distribution lines were characterized by the measurement of oxidation induction time(OIT) and chemical structure. In OIT measurement, hot water contacted cables showed the shorter OIT than non-contacted ones. Especially, hot water contacted insulation layer near insulation shield showed the shortest OIT. In chemical structure analysis, the antioxidant content was decreased and the acid concentration was increased by hot water ingress. From this results, it can be concluded that the hot water ingress to power cable may be accelerate the aging by means of antioxidant consumption.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.89-89
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• 2009

높은 소수반송자 수명(life-time)을 가지는 고품위 실리콘 기판은 고효율 실리콘 이종접합 태양전지 제작을 위한 중요 요소 기술 중 하나이다. 본 연구에서는 n-type c-Si 기판을 이용한 고효율 실리콘 이종접합 태양전지제작을 위해 hot water oxidation(HWO) 공정을 이용하여 고품위 실리콘 기판을 제작하였다. 실리콘 기판의 특성 분석은 Qusi-steady state photoconductance (QSSPC)를 이용하여 소수반송자 수명을 측정하였으며, 기판의 면저항 및 wetting angle을 측정하여 공정에 따른 특성변화를 분석하였다. Saw damage etching 된 기판을 웨이퍼 표면으로부터 particle, 금속 불순물, 유기물 등의 오염을 제거하기 위해 $60{\sim}85^{\circ}C$로 가열된 Ammonia수, 과산화수소수($NH_4OH/H_2O_2/H_2O$), 염산 과산화수소수($HCL/H_2O_2/H_2O$) 및 실온 희석불산(DHF) 중에 기판을 각각 10분 정도씩 침적하여, 각각의 약액 처리 후에 매회 10분 정도씩 순수(DI water)에서 rinse하여 RCA 세정을 진행한 후 HWO 공정을 통해 기판 표면에 얇은 산화막 을 형성시켜 패시베이션 해주었다. HF를 이용하여 자연산화막을 제거시 HWO 공정을 거친 기판은 매끄러운 표면과 패시베이션 영향으로 기판의 소수 반송자 수명이 증가하며, 태양전지 제작시 접촉저항을 감소시켜 효율을 증가 시킬수 있다. HWO 공정은 반응조 안의 DI water 온도와 반응 시간에 따라 life-time을 측정하여 진행하였으며, 이후 PE-CVD법으로 증착된 a-Si:H layer 및 투명전도 산화막, 금속전극을 증착하여 실리콘 이종접합 태양전지를 제작하였다.

• Journal of Environmental Science International
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• v.22 no.10
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• pp.1317-1325
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• 2013

Paulownia coreana is a medicinal, edible and industrial plant with the largest leaf, and is native to Korea. We evaluated the reducing power activities, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities (RSAs), nitrite scavenging activities (NSAs) and 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cation RSAs by solvent extraction of P. coreana bark by using $50^{\circ}C$ hot water and $25^{\circ}C$ methanol. The antioxidative effect of P. coreana bark extract on corn seed oil was evaluated using the Rancimat test. The extraction yields on dry weight basis with 15 folds of hot water and methanol were 23.88% and 5.30%, respectively; further the flavonoid content in the hot water extract was over 2.5 times more than that in the methanol extract. The DPPH RSA of the methanol extract was substantially higher than that of the water extract, whereas the NSA of the water extract was higher than that of the methanol extract at pH 1.2. The ABTS RSAs of the two extracts were almost the same as that of ascorbic acid and 2,6-ditertiarybutyl hydroxytoluene. The two extracts of P. coreana bark in this study were found to slightly improve the oxidation stability of corn seed oil.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.5
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• pp.25-30
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• 2010

The authors have studied on the corrosion resistance of the hot stamped steel sheets for the application to automotive parts. Recently automotive companies have focused on the hot stamped parts to meet the light weighting needs and the safe reason. Because of the cost reduction of the hot stamped parts, automotive companies increase the usage of the coated steel sheets, especially Al-Si coated steel sheets. The coated layer of Al-Si coated steel sheets contains up to 50% of Fe, which was diffused from the steel sheet, after hot stamping. The hot stamped steel sheet was not phosphated due to the oxidation layer of the coating, however, the result of the water resistance test is similar to that of the conventional GA steel sheets. The pitting depth and the weight reduction of the coated layer of hot stamped steel sheets are less than those of GA steel.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.2
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• pp.265-273
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• 2019

Objective: Terminalia arjuna plant, specially its leaves, bark, and roots, are widely used in traditional herbal medicine due to presence of bioactive components and being a rich source of natural antioxidants. But its fruit has not been used for any such purposes despite its potential to retard oxidation. Hence, the antioxidant potential of Arjuna fruit extract (AFE) in retarding lipid and protein oxidation of raw ground pork was evaluated during refrigerated storage for 9 days. Methods: The AFEs were prepared using different solvents viz. ethanol (EH), water, ethanol: water (60:40) and methanol:hot water (60:40). The AFEs were analysed for total phenolic content (TPC), 2, 2-diphenyl-1-picrylhydrazyl radical scavenging activity and reducing power. Water extract (WE) and ethanol-water extract (EH-WE) were selected and incorporated at 1.0% into freshly minced pork meat and compared with a synthetic antioxidant, in retarding lipid and protein oxidation during storage. Results: The TPC in AFEs using different solvents ranged from 11.04 to 16.53 mg gallic acid equivalents/g and extracts exhibited appreciable scavenging activity ranging from 50.02% to 58.62%. Arjuna extracts significantly (p<0.05) improved the colour score of meat samples by reducing the formation of metmyoglobin during storage. Both the AFEs (WE and EH-WE) significantly (p<0.05) lowered the thiobarbituric acid reactive substances value, peroxide formation and formation of protein carbonyls in raw pork than control sample during storage. Upon sensory evaluation of all samples, it was found that AFE treatment could prolong the storage period of meat samples, without influencing the colour and odour score, up to 6 days. Conclusion: AFEs used at 1% improved the oxidative stability, colour and odour score and prolonged the refrigerated shelf life of ground pork up 6 days. Therefore, AFE could be explored as an alternative natural antioxidant in retarding lipid and protein oxidation in meat products.

• Journal of Applied Biological Chemistry
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• v.43 no.3
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• pp.156-160
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• 2000

The possible mechanism of the DNA strand breaking activity of the hot-water extract of Fructus Chaenomelis (dried fruit of Chaenomeles sinensis) in a closed circular duplex replica form DNA (RFI DNA) was studied through agarose gel electrophresis under various conditions. Induction of DNA strand scission by the hot-water extract of C. sinensis occurred in dose and time-dependent manners. $Cu^{2+}$ was indispensable for the induction of DNA strand breakage. Exogeneous chelating agents inhibited the DNA breaking activity, conforming the catalytic action of $Cu^{2+}$ on generation of free radicals responsible for oxidative damage. Antioxidant enzymes and some radical scavengers were used to investigate the major radical species triggering the DNA strand scission, demonstrating that a highest inhibitory activity was found in the presence of catalase, while less in the presence of tiron (a scavenger for superoxide radical), 2-aminoethyl-isothiuroniumbromide-HBr, cysteamine (scavengers for hydroxyl radical), and 1,4-diazabicyclo [2,2,2] octane (a scavenger for singlet oxygen) in decreasing order. The findings implied that oxygen radical species generated in presence of transition divalent cation during the oxidation of some compounds contained in the hot-water extract of C. sinensis is mainly responsible for inducing genotoxicity.

• KSBB Journal
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• v.24 no.1
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• pp.101-105
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• 2009

Alcohol oxidation activities and optimization of extraction conditions of Rrhus verniciflua Stokes (RVS) extract were evaluated for the development of a functional biomaterial for improving liver function. When alcohol oxidation activities of RVS was analyzed, the Rrhus verniciflua Stokes bark (RVSB) were higher than the Rrhus verniciflua Stokes heartwood (RVSH). Alcohol oxidation activity value of RVSB increased in a concentration-dependent manner. In the comparative analysis between Hovenia dulcis Thunb (HOT) and Alnus japonica Steud (AJS) which was reported as a alcohol oxidation material, alcohol oxidation activity is much higher than the others. The experimental conditions were optimized for alcohol oxidation-active components production from RVSB. The extraction conditions such as temperature, time, pH and particle size were performed. It was recommended to extract the alcohol oxidation-active components from RVSB by hot water (pH 7.0) at $85^{\circ}C$ for 8 hours.

• Food Science of Animal Resources
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• v.39 no.3
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• pp.446-458
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• 2019

The aim of this study was to investigate the oxidative status and quality characteristics of four animal skin-derived fats extracted using an identical extraction method. Pressurized hot water extraction, a green extraction method, was used to extract animal skin fats (duck, chicken, swine, and bovine skin). Multiple experiments were performed during accelerated storage at $60^{\circ}C$ for 90 days. Quality characteristics, such as extraction yield, iodine value (IV), fatty acid composition, and fat viscosity were determined. In addition, indicators for oxidative status, including acid value (AV), peroxide value (PV), p-anisidine value (p-AV), thiobarbituric acid reactive substances (TBARS), conjugated dienes (CD), and total oxidation (totox) values were evaluated. The fat extraction yield was highest in bovine fat, followed by duck, swine, and chicken fats. The IV was higher in duck and chicken fats. Duck fats contained the most unsaturated fats and the least saturated fats. Fat oxidation indicators, such as PV, TBARS, and totox values, were relatively higher in duck fats during storage compared to the other fats. Other indicators, including AV, p-AV, and CD, were similar in duck, chicken, and swine fats. Viscosity was similar in all the tested fats but markedly increased after 70 days of storage in duck fats. Our data indicate that duck skin fat was more vulnerable to oxidative changes in accelerated storage conditions and this may be due to its higher unsaturated fatty acid content. Supplementation with antioxidants might be a reasonable way to solve the oxidation issue in duck skin fats.