• 대한기계학회논문집A
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• 제31권9호
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• pp.915-923
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• 2007

Rubber hoses for automobile radiators are apt to be degraded and thus failed due to the influence of contacting stresses of air and coolant liquid under thermal and mechanical loadings. The aging behaviors of the skin part of the hoses due to thermo-oxidative and electro-chemical stresses were experimentally analyzed. Through the thermo-oxidative aging test, it was shown that the surface hardness IRHD(International Rubber Hardness Degrees) of the rubber increased with a considerable reduction of failure strain as the aging time and temperature increased. On account of the penetration of coolant liquid into the skin part influenced by the electro-chemical degradation(ECD) test the weight of the rubber hose increased, whereas their failure strain and IRHD hardness decreased. The hardness of the hose in the side of the negative pole was the most deteriorated at the test site of the hose skin just below the coolant surface.

• 대한화장품학회:학술대회논문집
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• 대한화장품학회 2003년도 IFSCC Conference Proceeding Book I
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• pp.291-312
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• 2003

Reactive oxygen species are capable of damaging biomolecules such as lipids, proteins, and DNA, which can not only lead to various diseases, but also oxidative damage resulting aging. In our previous study, Cercis chinensis (Leguminosae) showed a potent antioxidant activity. Nineteen compounds were isolated through antioxidant activity-guided fractionation. The C. chinensis extract and some of the constituents exhibited a potent antioxidant activity on the free radicals and lipid peroxidation and a notable protective effect on the t-BuOOH induced oxidative damage. In vivo test of skin damage induced by UVB irradiation, the extract of C. chinensis and a constituent, piceatannol, exhibited a significant protective effect. The life-span of the HEK-N/F cells were extended by 1.21-2.12 fold as a result of the continuous administration of 3 $\mu\textrm{g}$/ml of the C. chinensis extract and the active constituents compared to that of the control. These observations were attributed to the inhibitory effect of the C. chinensis extract and its constituents on the age-dependent shortening of the telomere. Thus, C. chinensis was demonstrated to protect the skin cells against oxidative stress and inhibit thereby the cellular aging, followed by expectation as anti-aging cosmetic ingredient.

• 대한화장품학회:학술대회논문집
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• 대한화장품학회 2003년도 IFSCC Conference Proceeding Book II
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• pp.117-138
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• 2003

Reactive oxygen species are capable of damaging biomolecules such as lipids, proteins, and DNA, which can not only lead to various diseases, but also oxidative damage resulting aging. In our previous study, Cercis chinensis (Leguminosae) showed a potent antioxidant activity. Nineteen compounds were isolated through antioxidant activity-guided fractionation. The C. chinensis extract and some of the constituents exhibited a potent antioxidant activity on the free radicals and lipid peroxidation and a notable protective effect on the t-BuOOH induced oxidative damage. In vivo test of skin damage induced by UVB irradiation, the extract of C. chinensis and a constituent, piceatannol, exhibited a significant protective effect. The life-span of the HEK-N/F cells were extended by 1.21-2.12 fold as a result of the continuous administration of 3 $\mu\textrm{g}$/ml of the C. chinensis extract and the active constituents compared to that of the control. These observations were attributed to the inhibitory effect of the C. chinensis extract and its constituents on the age-dependent shortening of the telomere. Thus, C. chinensis was demonstrated to protect the skin cells against oxidative stress and inhibit thereby the cellular aging, followed by expectation as antiaging cosmetic ingredient.

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2006년도 학술발표대회 논문집
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• pp.27-31
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• 2006

Rubber hoses for automobile radiators are apt to degraded and thus failed due to the influence of contacting stresses of air and coolant liquid under thermal and mechanical loadings. The aging behaviors of the skin part of the hoses due to thermo-oxidative and electro-chemical stresses were experimentally analyzed. Through the thermo-oxidative aging test, it was shown that the surface hardness IRHD(International Rubber Hardness Degrees) of the rubber increased with a considerable reduction of failure strain as the aging time and temperature were large. On account of the penetration of coolant liquid into the skin part the weight of rubber specimens influenced by electro-chemical degradation (ECD) test increased, whereas their failure strain and IRHD hardness decreased. The hardness decreased further as the test site on the hose skin approached to the negative pole.

• 비파괴검사학회지
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• 제25권5호
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• pp.368-376
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• 2005

자동차용 냉각기 호스는 열과 기계적 하중 하에서 공기와 부동액의 접촉 스트레스로 인해 노화와 고장이 일어날 수 있다. 본 연구에서는 냉각기 호스재료인 EPDM(ethylene-propylene diene monomer)고무에 대해 열가속 및 산소 스트레스, 전기화학적 스트레스에 의한 표피층의 노화거동을 비파괴 평가하였다. 열가속 및 산소노화 시험결과 신장률의 저하와 함께 IRHD(International Rubber Hardness Degrees)경도가 증가하였다. 전기화학적 노화(electro-chemical degradation: ECD) 시험에서는 에틸렌글리콜 수용액의 침투로 인해 무게가 증가하였으며 신장률과 경도는 크게 저하되었다 또한 에틸렌글리콜 수용액이 표피층뿐만이 아니라 내부에까지 침투하여 고무내부구조와 미크로경도분포가 깊이에 따라 변화되었다. 즉, 열가속 및 산소노화와 ECD 노화는 미크로 경도와 화학구조분석에 의해 비파괴적 특성 평가가 가능함을 보였다.

• 생명과학회지
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• 제9권5호
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• pp.548-555
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• 1999

Long-term effects of Ganoderma lucidum (GL) on memory and oxidative stress of senescence-accelerated mice (SAM) were investigated. Senescence-resistant (R1) and prone (P8) strains of SAM were fed GL diets, premixed with low (20 mg/kg/day, T1) or high (200 mg/kg/day, T2) levels of GL powder for 9 months starting from young (3 months of age) or for 5 months starting from old (7 months of age). After the final feeding at 12 months of age, all animals were subjected to passive avoidance test for the evaluation of memory function. In addition, the changes in hepatic thiobarbituric acid-reactive substance (TBARS) and glutathione were analyzed. SAMP8 fed GL diets from old age (7 months) exhibited the improvement of memory, although GL rather inhibited the memory function of both SAMR1 and SAMP8 mice fed diets from young (3 months of age). Hepatic TBARS contents were decreased in SAMP8 fed high GL diet for 9 months and in SAMR1 fed low GL diet for 5 months. Hepatic glutathione content was also remarkably increased in SAMR1 following both feeding periods, and less extent in SAMP8 fed diet for 5 months of age. Taken together, it is proposed that GL extracts may play an anti-aging role through antioxidant action, and thereby may improve the senescence-related memory dysfunction.

• Toxicological Research
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• 제34권4호
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• pp.333-341
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• 2018

Ferulate is a phenolic compound abundant in wheat germ and bran and has been investigated for its beneficial activities. The aim of the present study is to evaluate the efficacy of ferulate against the oxidative stress-induced imbalance of protein tyrosine kinases (PTKs), protein tyrosine phosphatases (PTPs), and serine/threonine protein phosphatase 2A (PP2A), in connection with our previous finding that oxidative stress-induced imbalance of PTKs and PTPs is linked with proinflammatory nuclear factor-kappa B $(NF-{\kappa}B)$ activation. To test the effects of ferulate on this process, we utilized two oxidative stress-induced inflammatory models. First, YPEN-1 cells were pretreated with ferulate for 1 hr prior to the administration of 2,2'-Azobis(2-methylpropionamidine) dihydrochloride (AAPH). Second, 20-month-old Sprague-Dawley rats were fed ferulate for 10 days. After ferulate treatment, the activities of PTKs, PTPs, and PP2A were measured because these proteins either directly or indirectly promote $NF-{\kappa}B$ activation. Our results revealed that in YPEN-1 cells, ferulate effectively suppressed AAPH-induced increases in reactive oxygen species (ROS) and $NF-{\kappa}B$ activity, as well as AAPH-induced PTK activation. Furthermore, ferulate also inhibited AAPH-induced PTP and PP2A inactivation. In the aged kidney model, ferulate suppressed aging-induced activation of PTKs and ameliorated aging-induced inactivation of PTPs and PP2A. Thus, herein we demonstrated that ferulate could modulate PTK/PTP balance against oxidative stress-induced inactivation of PTPs and PP2A, which is closely linked with $NF-{\kappa}B$ activation. Based on these results, the ability of ferulate to modulate oxidative stress-related inflammatory processes is established, which suggests that this compound could act as a novel therapeutic agent.

• Food Science and Biotechnology
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• 제18권6호
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• pp.1311-1315
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• 2009

The objective of this study was to investigate the effects of sesaminol glucosides (SG) on age-related cognitive deficits in senescence-accelerated mice P8 (SAMP8). Male SAMP8 (9 month-old) were randomly divided into 3 groups and received diets containing 0, 0.25, or 0.5% SG for 12 weeks. Step-through latency of the SAMP8 control group was higher than that of the senescence-accelerated resistant mice (SAMR) group, whereas it was lowered in the SG-supplemented group on the passive-avoidance test. In the Morris water maze, the escape latency of the SAMP8 control group was increased and recovered in the 0.5% SG-supplemented group. The SG supplementation significantly decreased thiobarbituric acid reactive substance (TBARS) levels in brains of the SAMP8. On the other hand, catalase, superoxide dismutase, and glutathione peroxidase activities in brains of the SG supplemented group decreased compared with the SAMP8 control group. These results suggest that SG could attenuate cognitive deficits caused by aging through its antioxidant capacity.

• 한국약용작물학회지
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• 제15권5호
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• pp.352-356
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• 2007

The present study was investigated the anti-oxidative effects of aloe vera ingestion on brain and kidney in aged rats by monitoring several oxidative-related parameters. Male specific pathogen-free Fischer 344 rats were randomly divided into four groups of five rat each: Group A was fed test chow without aloe supplementation; Group B was fed a diet containing a 1% freeze-dried aloe filet; Group C was fed a diet containing a 1% charcoal-processed, freeze-dried aloe filet; and Group D was fed a diet containing a charcoal-processed, freeze-dried, whole leaf aloe in drinking water. Analyses of tissues were done at 4 months and 16 months of age. Results showed that a long-term intake of aloe, regardless of the preparation used, enhanced antioxidant defenses against lipid peroxidation, as indicated by reduced phosphatidylcholine hydroperoxide levels in both brain and kidney. The additional benefit of aloe intake on the anti-oxidative action was evidenced by enhanced superoxide dismutase and catalase activity in all aloe-ingested groups. Another beneficial effect of aloe shown in this study, although not an anti-oxidative parameter, was its cholesterol-lowering effect as detected in brain and kidney with significant decreases at age16 months of aloe-fed rats. Based on these findings, we conclude that a long-term dietary aloe supplementation modulated the anti-oxidative defense systems and cholesterol level.

• 대한화장품학회지
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• 제33권1호
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• pp.33-40
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• 2007

예로부터 황기는 민간에서 강장제로서 인삼 다음의 보약으로 쓰이고 있다. 본 연구에서는 황기의 성분 중 플라보노이드 화합물로 알려진 calycosin과 formononetin을 유효성분으로 함유하는 황기추출물의 항노화 효과에 대해 알아보았다. Calycosin과 formononetin의 함량은 효소처리 추출방법에 따라 차이가 있었으며, 두 가지 성분들의 함량에 따라 항산화효과 및 tyrosinase 활성 저해효과가 다르게 나타났다. 이러한 연구 배경으로 calycosin과 formononetin을 유효성분으로 함유하는 황기추출물의 피부주름개선 효과를 알아보기 위해 콜라겐 발현효과 및 MMP-1 발현 억제효과를 각각 측정하였다. 그 결과 황기추출물의 콜라겐합성은 증가하였으나, MMP-1 발현 저해효과는 크지 않았다. 또한 0.1% 황기추출물 함유 크림은 대조군에 비하여 피부주름 개선효과를 나타냈다. 이러한 결과를 볼 때 황기추출물은 주름개선용 기능성화장품 신소재로의 응용이 기대된다.