• 한국식품과학회지
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• 제33권6호
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• pp.693-699
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• 2001

식품내 존재하는 광감체를 제거함으로써 광산화를 억제하는 방법의 일환으로 방사선 조사시 광감체인 chlorophyII의 제거정도 및 최적 조사선량을 탐색하고 모델시스템으로서 linoleic acid 용액에 chlorophyII을 첨가하고 방사선 조사기술을 이용하여 기질의 산화없이 광감체를 제거하고자 chlorophyII b의 함량, 색도 및 과산화물가를 측정하였다. 방사선 조사선량이 증가할수록 chlorophyII b의 함량이 감소하였으며 2.517kGy이상의 선량에선 chlorophyII b 가 방사선 조사에 의해 완전히 파괴되었다. Linoleic acid 용액의 제조 직후 chlorophyII b의 함량은 2.88-2.91 ppm이었으나 20kGy의 방사선을 조사한 경우 chlorophyII b는 전혀 검출되지 않았으며 광조사에 의한 chlorophyII b의 함량은 방사선 비조사구의 경우 chlorophyII b의 함량이 광조사 시간이 경과함에 따라 약간씩 감소하였으나 방사선 조사구는 광조사 후에도 전혀 검출되지 않았다. 방사선을 조사한 후 광조사 시키는 동안 색도의 변화는 L값과 b값의 경우 비조사구에 비해 방사선 조사에 의하여 증가하였고 a값은 감소하였다. 과산화물가는 제조직후방사선 조사에 의하여 산화가 일어났으나 방사선 조사시 $N_2$ gas bubbling 처리한 경우에는 비조사구와 마찬가지로 전혀 산화가 일어나지 않았다. 또한 방사선 조사후 광조사 시킨 경우 chlorophyII b의 제거로 광산화는 일어나지 않았다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 추계학술대회 논문집
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• pp.509-510
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• 2006

• BMB Reports
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• 제48권5호
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• pp.289-294
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• 2015

Caesalpinia sappan is a well-distributed plant that is cultivated in Southeast Asia, Africa, and the Americas. C. sappan has been used in Asian folk medicine and its extract has been shown to have pharmacological effects. Two homoisoflavonoids, sappanol and brazilin, were isolated from C. sappan by using centrifugal partition chromatography (CPC), and tested for protective effects against retinal cell death. The isolated homoisoflavonoids produced approximately 20-fold inhibition of N-retinylidene-N-retinyl-ethanolamine (A2E) photooxidation in a dose-dependent manner. Of the 2 compounds, brazilin showed better inhibition (197.93 ± 1.59 μM of IC₅₀). Cell viability tests and PI/Hoechst 33342 double staining method indicated that compared to the negative control, sappanol significantly attenuated H₂O₂-induced retinal death. The compounds significantly blunted the up-regulation of intracellular reactive oxygen species (ROS), and sappanol inhibited lipid peroxidation in a concentration-dependent manner. Thus, both compounds represent potential antioxidant treatments for retinal diseases. [BMB Reports 2015; 48(5): 289-294]

• 폴리머
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• 제25권5호
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• pp.625-634
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• 2001

액상 이소프렌 고무에 무수 말레간(MAH)을 그라프팅시킨 후 2,2,6,6-tetramethyl-4-piperidinol (TMPO)를 반응시켜 hindered amine light stabilizer (HALS)가 함유된 새로운 고분자형 광안정제를 합성하고, SBR에 대한 광안정제로서의 특성을 관찰하였다. 새로운 고분자형 광안정제의 조성과 물리적 성질은 적정법, GPC 그리고 열중량 분석에 의하여 분석하였다. SBR의 광산화 반응에 대한 고분자형 광안정제의 효과를 254nm 자외선 조사에 따른 자외선 흡광도의 변화, 관능기 변화 그리고 잔막율로서 관찰한 결과, 새로운 고분자형 광안정제를 첨가함으로써 광산화 반응이 효과적으로 억제되었다. 또한, 고부자형 광안정제의 추출내성은 저분자량의 모델 화합물에 비하여 훨씬 우수하였으며, 고분자형 광안정제와 SBR의 상용성은 TMPO가 SBR 필름 표면에 균일하게 고루 분산되어 있어서 매우 우수하였다.

• 한국염색가공학회지
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• 제17권1호
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• pp.7-13
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• 2005

Continuous and intense UV irradiation on PTT film using two types of UV bulbs at different irradiation power level was carried out to modify surface characteristics of the film including zeta potential, wettability, surface energy, and dyeability. ESCA analysis of the irradiated film showed higher O/C ratio than the untreated film indicating photooxidation of outer surface layer. ATR analysis showed that the ester bonds were broken and some new groups were produced such as carboxylic acid, phenolic hydroxy, and other esters, implying that ester bonds of PTT was responsible for the observed photooxidation effect. The surface of the treated PTT film became more hydrophilic and wettable to water, coupled with increased surface energy. Polar component of the surface energy increased and nonpolar component decreased with increasing irradiation energy. The treatment also decreased zeta potential of the modified surface and nanoscale roughness increased with increasing irradiation. The dyeability of the treated films to catonic dyes was significantly improved by electrostatic and polar interaction between dye molecules and the anionic film surface. The UV irradiation seems to be a viable polymer surface modification technology, which has advantages such as no vacuum requirement and continuous process unlike plasma treatment.

• 한국염색가공학회지
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• 제18권5호
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• pp.35-41
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• 2006

Upon $UV/O_3$ irradiation cellulose acetate (CA) films showed modified surface properties such as increased hydrophilicity and surface roughness as well as increased dyeability to cationic dyes. UV treatment induced photoscission of acetyl groups in the main chain of CA resulting in decreased degree of substitution from 2.2 to 1.3. The slight decreases in reflectance and transmittance were caused by remarkably increased nano-scale surface roughness of the CA surface as much as 20-fold, which can destructively interfere with visible lights of wavelength lower thu 500nm. Water contact angle decreased from $54^{\circ}\;to\;14^{\circ}$ with increasing UV energy. Surface energy also increased slightly. The surface energy change was attributed to significant contribution of polar component rather than nonpolar component indicating surface photooxidation of CA film. The increased dyeability to cationic dyes in terms of both K/S and %E may be due to photochemically introduced anionic and dipolar dyeing sites on the film surfaces.

• Journal of Ginseng Research
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• 제14권3호
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• pp.379-384
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• 1990

In order to study the lipid peroxidation caused by light and the protective action it in biological memberane, reverse-phase evaporation liposome (REV) was employed as a model memberance and the effect of several antioxidants and ginseng water extracts were tested. In the presence of photosensitizer, liposome was oxidized easily and the oxidation index dut to the peroxidation was increased. The oxidation index of liposome was increased according to the increase in temperature. When dl-${\alpha}$-tocopherol, ${\beta}$-carotene or L-ascorbic acid was added into the reaction mixture, the photooxidation of liposome was inhibited. Ginseng water extract and crude saponin inhibited the rate of oxidation index of liposome in low concentration but increase in high concentration. On the other hand, when lipid hydroperoxide of liposome was tested by ferrothiocyanate method, ginseng water extract and crude saponin acted as antioxidants.

• 한국염색가공학회지
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• 제23권2호
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• pp.76-82
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• 2011

Ultra High molecular weight polyethylene(UHMWPE) films were photooxidized by UV/ozone irradiation. Reflectance of the irradiated films decreased in the low wavelength regions of visible light, indicating destructive interference of visible light due to roughened surface. The UV treatment developed the nano-scale roughness on the UHMWPE films surface, which increased by two-fold from 82.6 to 156.6nm in terms of peak-valley roughness. The UV irradiation caused the oxygen content of the UHMWPE film surface to increase. Water contact angle decreased from $83.2^{\circ}$ to $72.9^{\circ}$ and surface energy increased from 37.8 to 42.6mJ/$m^2$ with increasing UV energy. The surface energy change was attributed to significant contribution of polar component rather than nonpolar component indicating surface photooxidation of UHMWPE films. The increased dyeability to cationic dyes may be due to the photochemically introduced anionic and dipolar dyeing sites on the film surfaces.

• 한국응용과학기술학회지
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• 제4권1호
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• pp.19-22
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• 1987

To investigate the protective action of various antioxidants on the photooxidation of rice bran oil, it was irradiated with red and visible light in presence and absence antioxidants with or without sensitizer (methylene blue). 1. Rice bran oil with and without sensitizer in chloroform-ethanol (4:1, v/v) media was largely oxidized under visible light irradiation. on the other hand, rice bran oil without sensitizer was hardly oxidized under red light irradiation. 2. Rice bran oil with sensitizer was oxidized much faster than that without. And the absorbance of it irradiated with visible was increased more than that with red light. 3. The effectiveness of antioxidants on the rice bran oil photooxidation was same order as follows: Irradiation with visible light, no addition of sensitizer ${\beta}$-carotene > dl-{$\alpha}$-tocopherol > BHT > BHA Irradiation with visible light, addition of sensitizer ${\beta}$-carotene > BHT > dl-${\alpha}$tocopherol > BHA Irradiation with red light, addition of sensitizer ${\beta}$-carotene > BHA > BHT > dl-${\alpha}$-tocopherol From these results, we concluded that rice bran oil was largely oxidized under visible light irradiation, therefore it must be protected from photooxidative deterioration by the addition of antioxidants.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2001년도 추계학술대회 논문집
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• pp.225-226
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• 2001

휘발성 유기화합물(VOCs)은 광화학적 오존 형성으로 인한 간접 오염뿐만 아니라 그 자체가 독성을 지니고 있어 직접적으로도 인체에 유해한 영향을 줄 수 있으며, 유류 및 유기 용제를 사용하는 작업장에서뿐만 아니라 연소 관련 오염원이 없는 실내 환경에서도 일부 VOCs는 높은 농도를 나타낼 수 있으므로 작업장 및 실내 환경에서의 VOCs 처리에 대한 중요성이 증대되고 있다. (중략)