• Journal of Environmental Science International
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• v.16 no.4
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• pp.433-440
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• 2007

The photodegradation and by-products of the gaseous toluene with $TiO_2$ (P25) and short-wavelength UV ($UV_{254+185nm}$) radiation were studied. The toluene was decomposed and mineralized efficiently owed to the synergistic effect of photochemical oxidation in the gas phase and photocatalytic oxidation on the $TiO_2$ surface. The toluene by the $UV_{254+185nm}$ photoirradiated $TiO_2$ were mainly mineralized $CO_2$ and CO, but some water-soluble organic intermediates were also formed under severe reaction conditions. The ozone and secondary organic aerosol were produced as undesirable by-products. It was found that wet scrubber was useful as post-treatment to remove water-soluble organic intermediates. Excess ozone could be easily removed by means of a $MnO_2$ ozone-decomposition catalyst. It was also observed that the $MnO_2$ catalyst could decompose organic compounds by using oxygen reactive species formed in process of ozone decomposition.

• Korean Journal of Human Ecology
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• v.10 no.3
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• pp.263-274
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• 2001

This study investigated the dyeability on silk, wool and rotten fabrics dyed with Magnolia liliflora leafs. In addition, the fastness of washing, perspiration, rubbing, drycleaning and the effects of its pigment on bacterial reduction and uv-B protection were also investigated. The results were as follows : It was found that uv-visible absorption spectrum showed two strong absorption peaks in the range of $250{\sim}340nm$. The optimum dyeing condition of the pigments extracted from the Magnolia liliflora leafs was dyeing with 0.5% mordants and three repeated dyeing at $95^{\circ}C$ for 1hr. When the wool fabric was dyed with Magnolia liliflora leaf, dyeing properties was the best among the three fabrics. Washing fastness of dyed fabrics was very low, drycleaning fastness was good and the other fastness were good. Light fastness of three fabrics dyed by Magnolia liliflora leafs increased by mordant treatment, especially copper sulfate treatment. The bacterial reduction and uv-B protection of dyed wool fabric with Magnolia liliflora leafs also increased.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.28 no.1
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• pp.31-41
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• 2002

The production of matrix matalloproteinases(MMPs) by the UV irradiated skin fibroblast and the degradation of extracellular matrix(ECM) by these enzymes is known as one of the main reasons of photoaging. Recently, Fisher group showed that the MMP expression is mainly regulated by the mitogen-activated protein(MAP) kinas family, such as extracellular signal-regulated kinase(ERK), c-Jun amino-terminal kinase(JNK) and p38, each of which forms a signaling pathway. In this work we first examined the effect of nitric oxide (NO) on the production of MMP-1 and MMP-2 by the human dermal fibroblasts (HDFs). NO is a multifunctional messenger molecule generated from L-arginine and involved in many kinds of signaling pathway. We found that the treatment of HDF with NO donor, sodium nitroprusside (SNP) enhanced the expression of MMPs with or without UV irradiation and the treatment with nitric oxide synthase (NOS) inhibitors resulted in the significant decrease of MMPs production. From these results, we concluded that the production of MMPs by the UV irradiated HDF is regulated through the signaling pathway involving NO and cyclic GMP.

• Journal of Korean Society on Water Environment
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• v.30 no.1
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• pp.95-101
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• 2014

Overall studies for the N-nitrosodimethylamine (NDMA) formation and treatment methods were conducted. In this study, occurrence in several countries and emerging treatment technologies of NDMA were generally reviewed. The NDMA formation was dependent on pH, contact time, and molar ratio (monochloramine/dimethylamine). The formation was rapidly increased when the molar ratio was greater than 1. It was likely that monochloramine could be related to stimulate NDMA formation. NDMA concentrations in water supply and wastewater plants after disinfection were approximately 10 ng/L and 100 ng/L, respectively. UV oxidation and adsorption processes are regarded as effective technologies for the NDMA removal. It is suggested that the UV oxidation with proper lamps is applied in water supply system.

• Food Science and Preservation
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• v.16 no.3
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• pp.454-458
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• 2009

The effect of UV-C irradiation on microbial growth and quality of red pepper powder during storage was examined. Red pepper powder was irradiated with doses of 27, 54, or $108\;kJ/m^2$ and stored at $20^{\circ}C$ for 4 weeks. UV-C treatment of red pepper powder decreased the populations of total aerobic bacteria and Bacillus cereus in proportion to radiation dose. In particular, total aerobic bacteria and B. cereus populations decreased by 1.03 and 0.90 log CFU/g after irradiation at $108\;kJ/m^2$, respectively, compared with control values. UV-C irradiation caused negligible changes in the Hunter color L, a, or b values. Sensory quality results on red pepper powder were not significantly different between treatments. Therefore, UV-C irradiation can be used to inhibit microbial growth in red pepper powder, without impairing quality during storage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.2
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• pp.84-90
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• 2005

The effects of UV-B radiation on the seedling growth, carbohydrate metabolism and antioxidants activities of rice (Oryza sativa L.) were investigated under environmentally controlled chamber. Supplementary UV­B radiation reduced dry matter as well as leaf area, there­fore, relative growth rates (RGR) of seedlings were decreased by up to half compared to control. Photosynthetic products such as soluble sugars and starch were rapidly and significantly reduced by within 1 day of enhanced UV-B radiation due to the inhibition and degradation of photosynthetic processes and thylakoid membrane integrity. In our study, nonstructural carbohydrate levels were proved to be a main indicator on UV-B­induced stress. The behavior of SOD, CAT, APX and POD activities was monitored in the leaves of rice seedlings subjected to UV-B radiation. Under UV-B treatments, SOD activity was initially increased, whereas CAT and POD activities were slowly and slightly increased. However, APX activity showed no presumable results with an increase of UV-B dose. In leaves of rice seedlings, supplementary UV-B radiation caused an increase in free putrescine and spermidine, however spermine remained unaltered, although 24-hrs UV-B treatment slightly increased. This result presumes that an excess UV-B dose may induce ethylene biosynthesis (senescence) rather than polyamine biosynthesis (defense).

• Journal of Korean Society of Water and Wastewater
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• v.23 no.1
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• pp.69-75
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• 2009

The characteristics of disinfection and organic removal were investigated with pulse UV lamp in this study. The intensity and emission wavelength of pulse UV Lamp were compared with low pressure UV lamp. The emission spectrum range of pulse UV lamp was between 200 and 400 nm while the emission spectrum of low pressure UV lamp was only single wavelength of 254nm. 3 Log inactivation rate of B. subtilis spore by pulse UV and low pressure UV irradiation was determined as $44.71mJ/cm^2$ and $57.7mJ/cm^2$, respectively. This results implied that wide range of emission spectrum is more effective compared to single wavelength emission at 254nm. 500ng/L of initial 2-MIB concentration was investigated on the removal efficiency by UV only and $UV/H_2O_2$ process. The removal efficiency of UV only process achieved approximately 80% at $8,600mJ/cm^2$ dose. 2-MIB removal rate of $UV/H_2O_2$ (5 mg/L $H_2O_2$) process was 25 times increased compared to UV only process. DOC removal efficiency for the water treatment plant effluent was examined. The removal efficiency of DOC by UV and $UV/H_2O_2$ was no more than 20%. Removal efficiency of THMFP(Trihalomethane Formation Potential), one of the chlorination disinfection by-products, is determined on the UV irradiation and $UV/H_2O_2$ process. Maximum removal efficiency of THMFP was approximately 23%. This result indicates that more stable chemical structures of NOM(Natural Organic Matter) than low molecule compounds such as 2-MIB, hydrogen peroxide and other pollutants affect low removal efficiency for UV photolysis. Consequently, pulse UV lamp is more efficient compared to low pressure lamp in terms of disinfection due to it's broad wavelength emission of UV. Additional effect of pulse UV is to take place the reactions of both direct photolysis to remove micro organics and disinfection simultaneously. It is also expected that hydrogen peroxide enable to enhance the oxidation efficiency on the pulse UV irradiation due to formation of OH radical.

• Journal of the Korean Society of Clothing and Textiles
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• v.23 no.6
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• pp.909-918
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• 1999

The indigo-dyed blue denim garments are favored not only by young people but also by almost everyone of life, In the early years they were casually worn on most occasions but became universal recently. Such denim garments are treated with various process to give it optimal softness and color contrast of blue and white. The processess can generate photoyellowing and thus the yellowing may damage their appearance and quality. So this study is to find the solutions to reduce the photoyellowing problem. For this prupose sample denim were treated with cellulase fluorescent brightener UV absorbent etc. The results were as follows; The yellowing would be more accelerated by fluorescent brightening. Since the yellowing was reduced by 90% In particular the application of the UV absorbent before using of the fluorescent brightener was most effective. The optimal concentration was 0.5% (o.w.f) and the benzophenone compounds were found most effective for the indigo denim. And reduction effect of yellowing by UV absorbent was lowered with repeated laundering but metal compound treatment on fabric made a removal of UV absorbent by laundering prevented.

• International Journal of Industrial Entomology and Biomaterials
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• v.17 no.1
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• pp.121-124
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• 2008

The caspase family proteins play an important role in programmed cell death (apoptosis). To date, the expression profiles of the caspase family genes in Bombyx mori (Bm) are poorly known. In this study, we examined the expression profiles of two novel Bm caspase family genes (ice-2 and ice-5), the potential change of the mitochondrial membrane and the morphology in Bm cells after stimulation of ultraviolet (UV) irradiation. The results showed the potential change of the mitochondrial membrane occurred at 5 hours after UV irradiation treatment. Analysis of fluorescent quantitative RT-PCR demonstrated that both the ice-2 and ice-5 might be involved in UV induced apoptosis in Bm cells. Notably, after UV irradiating, expression pattern of ice-2 and ice-5 were remarkably different. The ice-2 gene was highly expressed at two time points, 0.5 and 5 hours after UV stimulating, while the expression level of ice-5 only peaked at 5 hours after UV stimulating. It indicated that apoptosis induced by UV irradiation was involved in the mitochondrial pathway and the two isoforms of Bm ice may act but play different role during the apoptosis of Bm cells.

• Textile Coloration and Finishing
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• v.18 no.6 s.91
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• pp.49-56
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• 2006

Surface treatment using UV irradiation was carried out to improve optical properties of polarizing films. The effects of UV energy of the UV-treated PVA films were investigated by measuring reflectance, surface roughness, contact angles, ESCA, and ATR. Reflectance decreased at wavelength of 450 nm or less and surface roughness increased with increasing UV energy. Water contact angle increased in the irradiated PVA films and surface energy decreased with increase in w energy. An analysis showed that the OH groups were broken and some new groups were introduced such as C=C and C=O bonds together with increased $O_{1s}/C_{1s}$, resulting in the observed surface modification effect. Surface modified PVA polarizing films showed improvement in light transmittance of polarizing films at high wavelength region without deteriorating polarization efficiency, which was not affected by UV irradiation sequence during manufacturing processes such as coloring and drawing.