• Analytical Science and Technology
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• v.25 no.3
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• pp.197-206
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• 2012

Ambers are composed of polymer molecules which contain aromatic moieties such as benzene, naphthalene, phenanthrene and anthracene. They emit fluorescence when irradiated with ultraviolet light, which was used for confirming an amber. The fluorescence of amber, however, tends to decrease as the surface of amber is weathered with light, heat, oxygen for a long time. In this study, the reliability of confirming amber with its fluorescence by measuring the changes of fluorescence after artificial aging. Aging factors were UV light (${\lambda}$=340 nm), oxygen with heat (100%, $90^{\circ}C$) and heat ($90^{\circ}C$) and aging time was for 5, 15, 30 and 60 days, respectively. In the excitation and emission spectra of amber, the intensity decreased and the maximal wavelength was shifted to longer wavelength with artificial aging time. Especially, there was a drastic decrease in the intensity of spectra to 1.7% of initial value after 60 days aging under oxygen with heat. Only in Colombian amber there showed an increase of fluorescence intensity for a certain aging time, which could be explained by the production of aromatic ring in the presence of light and heat. Conclusively, the fluorescence can be lessened by the natural weathering with light, heat and oxygen and it is not accurate to recognize amber just with UV irradiation method.

• Korean Journal of Environmental Biology
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• v.34 no.1
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• pp.48-55
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• 2016

This study investigates the effect of effluent organic matter (EfOM) from sewage wastewater treatment plants on estrogenic activity reduction of bisphenol A (BPA) by UV photolysis. The EfOM and Suwannee River natural organic matter (SR-NOM) as reference were isolated into hydrophobic (HPO), transphilic (TPI) and hydrophilic (HPI) fractions depending on polarity. The specific ultraviolet absorbance (SUVA) analysis indicated that EfOM showed similar properties to microbially derived organic matters with low hydrophobicity, which is different from SR-NOM having high hydrophobicity. UV irradiation upto 3 hr significantly reduced SUVA values of both EfOM and SR-NOM (p<0.0001), depending on the polarity of organic matters. In the absence of organic matters, the relative estrogenic activity (REA) of BPA ($5.0{\times}10^{-5}M$) was decreased from 86% to 63% by UV photolysis (2 hr). However, the decrease of mean REA was from 68% to 37% in the presence of organic matters, which was significantly independent on the type (EfOM or SR-NOM) and polarity (HPO, TPI or HPI) of organic matters (p>0.05). As a result, the reduced REA by UV photolysis of BPA with and without organic matters was 31% and 23%, respectively, suggesting that both EfOM and SR-NOM accelerated the photolytic reduction of BPA estrogenic activity.

• Food Science of Animal Resources
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• v.33 no.3
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• pp.390-394
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• 2013

The aim of this study was to determine the optimal storage condition of pre-packed Hanwoo beef without freezing. Hanwoo loin was purchased from a local distributor at 48 h after slaughter, then sliced in $1.5{\pm}0.5$ cm thickness, and packed in a polyethylene (PE) tray covered with linear low-density polyethylene (LLDPE) film. The studied factors to set the optimal storage condition were chamber temperature (5, 2.5 and $-1^{\circ}C$ for 14 d), cooling method (direct and indirect cooling system), and ultraviolet (UV) light irradiation for beef surface sterilization (0, 30, 60, and 120 min). The changes of pH, thiobarbituric acid reactive substances (TBARS) and number of aerobic bacteria were measured during storage. Beef samples stored in $-1^{\circ}C$ showed the minimal increasing rate in TBARS and microbial growth. After 15 d of storage, there was no significant difference in pH and TBARS values. However, the microbial population of beef stored in direct type cooling chamber ($4.25{\pm}0.66$ Log CFU/g) was significantly lower than that of beef stored in indirect type chamber ($6.47{\pm}0.08$ Log CFU/g) (p<0.05). After 4 d of storage, 60 or 120 min UV light irradiated beef samples showed significantly lower microbial population, and at 14 d of storage, 60 min UV irradiated beef sample showed significantly lower microbial population ($3.14{\pm}0.43$ Log CFU/g) than control ($4.46{\pm}0.13$ Log CFU/g) (p<0.05). However, TBARS values of 60 or 120 min UV light irradiated beef samples were significantly higher than non-irradiated beef sample after 4 d of storage (p<0.05).

• Applied Biological Chemistry
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• v.18 no.1
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• pp.23-29
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• 1975

This experiment was conducted to study the effects of temperature and pH upon the acid productivity of the acid producing mutant induced by the treatment of ultraviolet light, and to identify the producing acid by PPC and p-oxydiphenyl method. Chemical composition of Takju mash brewed with selected yeast and producing acid were observed and the results were as follows. 1) There was no apprecible difference in acid producing activity of mutant at $25^{\circ}C\;to\;30^{\circ}C$. 2) The acid producing activity of mutant was little below pH 4 and was gradually increased according to approach nenutral, and the accumulation of acid was amounted to 0.5-0.7% as a lactic acid at pH 5 to 7 within 48 hrs of fermentation. 3) The acid produced by mutant was detected to the lactic acid. 4) In the cases of the Takju was brewed with the starter from the acid producing mutant the requirement of Ipkuk was 5% for all the raw materials, on the contrary, using orginal strain the requirement of Ipkuk was 20%. 5) In the case of both starters from the acid producing mutant and orginal strain were added at different brewing times, and only Bunkuk was used as a saccharifying agent (without Ipkuk), Takju was able to brewed more repidly and successfully than the case of general process.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.11
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• pp.1540-1545
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• 2012

To investigate the inhibitory effects of Lespedeza cuneataextract (LC) on photo aging, skin aging was induced by UVB irradiation of hairless mice for 5 weeks. The skin erythema indices for the positive control (PC) and Lespedeza cuneata extract (LC-1%, 3%, and 5%) groups were lower than that of the control group. However, both lipid and water capacities of the PC and LC-3% groups were significantly higher than those of the control group. Skin wrinkles in the PC and LC-3% groups formed in a pattern of shallow furrows and thin crests. Skin TBARS contents and XO activity in the LC group were lower than those of the control group. The activities of GSH, SOD, and CAT in the LC-3% group were significant higher than those of the control group. Therefore, Lespedeza cuneata extract could be an effective natural herbal material for the inhibition of skin aging in hairless mice skin.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.429-429
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• 2007

For various applications of liquid crystal displays (LCDs), the uniform alignment of liquid crystal (LC) molecules on treated surfaces is significantly important. Generally, a rubbing method has been widely used to align the LC molecules on polyimide (PI) surfaces. Rubbed PI surfaces have suitable characteristics, such as uniform alignment. However, the rubbing method has some drawbacks, such as the generation of electrostatic charges and the creation of contaminating particles. Thus, we strongly recommend a non contact alignment technique for future generations of large high-resolution LCDs. Most recently, the LC aligning capabilities achieved by ultraviolet and ion-beam exposures which are non contact methods, on diamond-like carbon (DLC) inorganic thin film layers have been successfully studied because DLC thin films have a high mechanical hardness, a high electrical resistivity, optical transparency, and chemical inertness. In addition, nitrogen-doped DLC (NDLC) thin films exhibit properties similar to those of the DLC thin films and a higher thermal stability than the DLC thin films because C:N bonding in the NDLC thin filmsis stronger against thermal stress than C:H bonding in the DLC thin films. Our research group has already studied the NDLC thin films by an ion-beam alignment method. The $SiN_x$ thin films deposited by plasma-enhanced chemical vapor deposition are widely used as an insulation layer for a thin film transistor, which has characteristics similar to those of DLC inorganic thin films. Therefore, in this paper, we report on LC alignment effects and pretilt angle generation on a $SiN_x$, thin film treated by ion-beam irradiation for various N ratios

• Polymer(Korea)
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• v.38 no.1
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• pp.43-48
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• 2014

In this paper, we made a new polycationic polymeric liposome composed of low molecular weight polyethylenimine (PEI) and 10,12-pentacosadiynoic acid (PCDA). PCDA liposome was prepared by ultraviolet irradiation. PEI was further conjugated on the surface of the polymerized PCDA liposome using coupling reagents to make PCDA-PEI. The blue-to-red transition of PCDA liposome was observed during the coupling reaction. The size distribution of liposome and complexes with plasmid DNA was measured by dynamic light scattering (DLS). The complex formation was also identified by agarose gel electrophoresis and PicoGreen reagent assay. We confirmed the complex formation of the polymeric liposome with DNA and then performed transfection and cytotoxicity assay in HEK 293 and HeLa cells. As a result, PCDA-PEI showed significant gene transfection efficiency and low cytotoxicity. This study shows that PEI-conjugated PCDA liposome could be an efficient gene or drug delivery carrier.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.5
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• pp.505-512
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• 2021

A 3D model was developed to calculate the UV intensity of a submerged-type UV disinfection reactor. Numerical experiments were conducted by inputting the design factors of an open channel-type disinfection reactor and a pipe-type disinfection reactor that were installed in an actual sewage treatment plant. The following data were obtained: The average UV intensity of the installed open channel-type reactor and pipe-type reactor was 7.87 mW/cm² and 13.09 mW/cm², respectively; the UV dose reflecting the UV irradiation time and taking into account attenuation effects such as mixing imbalance, lamp aging, temperature, and fouling, was expected to be 21.1 mJ/cm² and 24.8 mJ/cm², respectively, and these values are 5 % and 24 % higher than the target UV dose of 20 mJ/cm², respectively. By using the UV3D model, the optimal lamp position, which maximizes the average UV intensity without changing the size of the disinfection reactor or lamp output power, can be found. In this case, by only adjusting the lamp position, the average UV intensity can be increased by 0.9 % for the open channel-type and 0.5 % for the pipe-type, respectively. A better average UV intensity can be obtained by model simulation. By adjusting the horizontal and vertical ratio of the open channel-type reactor and by moving the lamp position, the average UV intensity can be increased by 7.4 % more than the present case.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.45 no.2
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• pp.151-159
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• 2019

Ergothioneine has been known as an excellent antioxidant and a cellular protector against oxidative damage in vivo. In the present study, ergothioneine was demonstrated to possess antioxidant and anti-glycation activities. The radical scavenging activity of ergothioneine enhanced the viability of human dermal fibroblasts (HDFs) exposed to ultraviolet (UV) light. The UVA irradiation increased the proportion of senescence-associated ${\beta}$-galactosidase (SA-${\beta}$-gal) positive cells in comparison with the normal control group. The treatment of UVA-irradiated HDFs with ergothioneine decreased the level of SA-b-gal (by approximately 45% at an ergothioneine concentration of $400{\mu}M$) compared with the UVA-irradiated HDFs. We also found that ergothioneine inhibited production of glyceraldehyde-derived advanced glycation endproducts (AGEs) in a concentration-dependent manner. The ergothioneine educed carboxymethyl-lysine (CML) expression in comparison to the glyoxal treatment. In addition, in the Western blot analysis, treatment of glyoxal-stimulated HDFs with ergothioneine resulted in a dose-dependent decrease in the expression level of the receptor for AGE (RAGE). These results suggest that ergothioneine may have potent anti-aging effects and could be used as a cosmetic material against cellular accumulation of AGEs.

• Clean Technology
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• v.25 no.2
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• pp.123-128
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• 2019

$Bi_2MoO_6$ catalysts were successfully synthesized using ethylene glycol monomethyl ether (EGME), glycerol (GL), ethylene glycol (EG), and water as solvents by a conventional hydrothermal method. The synthesized catalysts were characterized by XRD, DRS, BET, SEM, and PL, and we also investigated the photocatalytic activity of these materials for the decomposition of Rhodamin B under visible light irradiation. The XRD results revealed the successful synthesis of 12-18 nm, well-crystallized ${\gamma}-Bi_2MoO_6$ crystals with an Aurivillius structure regardless of solvent. In addition, the $Bi_2MoO_6$ catalysts prepared below $140^{\circ}C$ showed an amorphous phase; however, those prepared above $160^{\circ}C$ showed well-crystallized ${\gamma}-Bi_2MoO_6$ crystals. All the catalysts have a similar absorption spectrum from the ultraviolet region up to the visible region less than 470 nm. This result suggests that all the $Bi_2MoO_6$ catalysts are potential visible-light-driven photocatalysts. The $Bi_2MoO_6$ catalysts prepared using EGME as a solvent showed the highest photocatalytic activity. In addition, the $Bi_2MoO_6$ catalysts prepared at $180^{\circ}C$ showed the highest photocatalytic activity. The PL peaks appeared at about 560 nm at all catalysts and the excitonic PL signal was proportional to the photocatalytic activity for the decomposition of Rhodamin B. This suggests that the stronger the PL intensity, the larger the amount of oxygen vacancies and defects, and the higher the photocatalytic activity.