• Applied Chemistry for Engineering
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• v.27 no.2
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• pp.221-226
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• 2016

Production of eco-friendly and biologically harmless materials is strongly required in all industries. In particular, reducing volatile organic compounds in coating processes is extremely important to secure worker's safety. During recent two decades, extensive research works on water-borne polyurethane dispersion (PUD) have been continuously developed as an alternative to solvent-borne polyurethane. However, PUD was shown inferior mechanical properties to the organic solvent-borne polyurethane due to a limit to the molecular weight increase, which resulted in the limit of applications. To overcome this drawback, several approaches have been examined such as polymer blends and thermal/radiation induced crosslinking. Among these methods, the radiation curing system was suitable for industrialization because of the high crosslinking density and fast curing speed. In this study, we overcame the drawback for PUD via introducing benzophenone radiation curable units to PUD. We synthesized PUD films which possessed good dispersion in water for 30 days, increased Tg and Td more than $5^{\circ}C$ after UV curing film as well as improved young's modulus more than double.

• Journal of radiological science and technology
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• v.44 no.3
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• pp.253-260
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• 2021

The purpose of this study is to measure of growth and chlorophyl in barley exposed by X-ray. Barley seed was soaked 24h duration in water, then was classified into two group; pre-seed germination group (Pre-G) or post-seed germination group (Post-G). Also, divided as control subgroup and experimental subgroup(10Gy, 20Gy, 30Gy) in each group. Experimental subgroups were exposed by X-ray using linear accelerator (Clinac IS, VERIAN, USA). Expose condition was 6 MV X-ray, SSD 100 cm, 18×10 cm, 600 MU/min. Length was measured every day for 10 days and 10th day for weight. Chlorophyl was analyzed using spectrophotometer(uv-1800, shimadzu, japan) in l0th day. Data analysis was performed using SPSS ver 22.0(Chicago, IL, USA), ANOVA test (Dunnett_T3) between control subgroup and experimental subgroup in group and Independent T-test between Pre-G and Post-G in subgroup. In Pre-G, length of barley was significantly difference between control and 30Gy in 4th day (4.3 vs. 1.5, p= 0.011). Length of 30Gy was statistical difference with control(10th day; 14.4 vs. 6.3, p < 0.01), and was not in 10Gy or 20Gy in all day. In experimental subgroup, length was shorter as increasing radiation dose. In Post-G, length of barley was not difference statistically between control and experimental subgroup in first day, but more difference between two subgroup with increasing duration after exposing. Length of experimental subgroup was shorter significantly compared with control in 10th day, and no significant difference between experimental subgroup. Density of chlorophyl was increasing with increasing radiation dose in Pre-G and Post-G. Chlorophyl density of control was lower than 30Gy; 0.26ppm in Pre-G, 0.29ppm in Post-G). Growth and chlorophyl of barley was effected by X-ray. It is expected to be used as basic data for future radiobiological research.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.30 no.2
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• pp.227-233
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• 2004

Chronic exposure to solar radiation, particularly ultraviolet (UV) light, causes a variety of adverse reactions on human skin, such as sunburn, photoaging and photocarcinogenesis. Free radicals and reactive oxygen species (ROS) caused by UV exposure or other environmental facts play critical roles in cellular damage. And, repeated-UV irradiation activated the expression of the matrix metalloproteinase (MMP) and induced skin irritation. Therefore, the development of effective and safe photoprotectants that can reduce and improve the skin damage has been required. The purpose of this study was to investigate the photo-protective effect of several chinese medical plants (Juniperus chinensis) on the UV -induced skin cell damages. We tested free radical and superoxide scavenging effect in vitro. Fluorometric assays of the proteolytic activities of MMP-1 (collagenase) were performed using fluorescent collagen substrates. UVA induced MMP-1 synthesis and activity were analyzed by enzyme-linked immunosorbent assay (ELISA) and gelatin-based zymography in skin fibroblasts. We also examined anti-inflammatory effects by the determination test of proinflammatory cytokine, interleukin 6 in HaCaT keratinocytes. Expression of prostaglandin E$_2$ (PGE$_2$) after UVB irradiation was measured by competitive enzyme immunoassay(EIA) using PGE$_2$ monoclonal antibody. In the human skin we tested anti-irritation effect on the SLS-induced damage skin after appling the extract containing emulsion. We found that Juniperus chinensis extract had potent radical scavenging effect by 98% at 100$\mu\textrm{g}$/mL. The extract of Juniperus chinensis showed strong inhibitory effect on MMP-1 activities by 97% at 100 $\mu\textrm{g}$/mL and suppressed the UVA induced expression of MMP-1 by 79% at 25$\mu\textrm{g}$/mL. This extract also showed strong inhibition on MMP-2 activity in UVA irradiated fibroblast by zymography. In the test of proinflammatory cytokines of human keratinocytes Juniperus chinensis extract decreased expression of interleukin 6 about 30%. The amount of PGE$_2$ by HaCaT keratinocytes was significantly increased at the doses of above 10 mJ/$\textrm{cm}^2$ of UVB (p < 0.05). At the concentrations of 3.2-25$\mu\textrm{g}$/mL of this extract, the production of PGE$_2$ by HaCaT keratinocytes (24 h after 10mJ/$\textrm{cm}^2$ UVB irradiation) was significantly inhibited in culture supernatants (p < 0.05). In SLS-induced skin irritation model in vivo, we found to reduce skin erythema and improve barrier recovery after appling Juniperus chinensis extract containing emulsion when compared to irritated non-treated and placebo-treated skin. Our results suggest that Juniperus chinensis extract can be effectively used for the prevention of UV and SLS-induced adverse skin reactions and applied as anti-aging and anti-irritation cosmetics.

• Radiation Oncology Journal
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• v.23 no.1
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• pp.9-16
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• 2005

Purpose : To prospectively evaluate the use of positron emission tomography with the glucose analog fluoro-deoxyglucose (FDG-PET) to deoxyglucose (FDG-PET) to predict disease-free survival (DFS) after concurrent chemo-radiotherapy (CCRT) in patients with non-disseminated nasopharyngeal carcinoma (NPC). Materials and Methods : We studied 41 patients with non-disseminated NPC scheduled to undergo platinum-based CCRT were eligible for this study. Patients were studied by FDG-PET prior to the CCRT. FDG uptake of tumors were measured with the maximal standardized uptake value (SUV). Results : Complete response rate was $100\%$. In ten patients who presented with any component of treatment failure, the median $SUV_{max}$ was 8.55 (range: $2.49\~14.81$) in any component of failure and the median $SUV_{max}$ was 5.48 (range: $2.31\~26.07$) In the remaining patients without any such failure. Patients having tumors with high FDG uptake had a significantly lower 3-year DFS ($51\%\;{\nu}91\%$, p=0.0070) compared with patients having low uptake tumors. Conclusion : FDG uptake, as measured by the SUV, has potential value in predicting DFS in NPC treated by CCRT, High FDG uptake may be a useful parameter for Identifying patients requiring more aggressive treatment approaches.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.3
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• pp.184-190
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• 2016

We investigated the antioxidative and protective effects of corn silk (Zea mays L.) ethanol extracts on human HaCaT cells and erythrocytes. The NICS-2 fraction, extracted from corn silk, exhibited favorable 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid (ABTS) radical scavenging activities with $IC_{50}$valuesof$13.3{\pm}0.3{\mu}g/mL$ and $14.2{\pm}0.1{\mu}g/mL$ when compared with those of ${\alpha}$-tocopherol, a positive control, with $IC_{50}=10.4{\pm}02.2$ and $22.2{\pm}3.6{\mu}g/mL$, respectively. In addition, we investigated skin protection effects of NICS extracts of corn silk in HaCaT keratinocytes. To investigate the pharmacological potential of NICS-1 and NICS-2 extracts of corn silk on UV-B-induced damage in HaCaT cells, we measured the activity of interleukin (IL) 1a. Our results showed that all the corn silk extracts inhibited the UV-B-induced activity of IL-1a. In particular, NICS-1 extracts of corn silk significantly suppressed IL-1a activity in a dose-dependent manner without inducing cytotoxicity. These results indicate that the ethanol extracts of corn silk (Zea mays L.) could function as natural cytoprotective agents and antioxidants in biological systems, particularly the skin exposed to UV radiation, by protecting cellular membrane against reactive oxygen species (ROS).

• Microbiology and Biotechnology Letters
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• v.43 no.3
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• pp.275-279
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• 2015

Micro-algae are unicellular photosynthetic organisms and produce pigments such as chlorophyll and carotenoid. Chlorella contains a lot of protein and functional components like lipids, chlorophyll and carotenoids. In this study we induced mutants of Chlorella vulgaris (C. vulgaris) through ultraviolet radiation (UV-B) and selected two mutants by pigment (chlorophyll and carotenoids) content. We named the mutants ‘UBM1-2’, ‘UBM2-57’ and they were cultivated for 21-days. Cell growth, dry cell weight, protein content, lipid and pigments content were measured. The results indicated that the mutants displayed slower cell growth, lower dry cell weight and protein content than the wild type. However, for UBM1-2 the lipid content was 21% higher than the wild type. In addition, the mutants’ chlorophyll content was 37% and 89% higher than the wild type and the carotenoids content was 27% and 70% higher than the wild type, respectively.

• Journal of the Korean GEO-environmental Society
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• v.17 no.2
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• pp.5-11
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• 2016

$MWCNT-TiO_2$ nano composites and $Ag-MWCNT-TiO_2$ nano composites were prepared from Multi-Walled Carbon NanoTube (MWCNT), titanium (IV) butoxide (TNB) solution and silver nitrate ($AgNO_3$) by the sol-gel method. The dispersion and structure of Ag in the synthesized composites was observed by Scanning Electron Microscopy (SEM) and Field Emission Transmission Electron Microscopy (FE-TEM). X-Ray Diffraction (XRD) patterns of the composites showed that the composites contained an anatase phase. The Energy Dispersive X-ray spectroscopy (EDX) showed the presence of C, O, Ti and Ag peaks. The $TiO_2$ particles were distributed uniformly in the MWCNT network, and Ag particles were virtually fixed on the surface of the tubes. Also decomposition of the methylene blue was investigated according to UV radiation times for study photocatalytic activity. $Ag-MWCNT-TiO_2$ nano composites show high photodegradation than $MWCNT-TiO_2$ nano composites. The results indicate that the high conductivity of Ag improved the photoactivity of the $MWCNT-TiO_2$ composite.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.8
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• pp.4086-4092
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• 2013

Mycosporine-like amino acids (MAAs) are UV-absorbing substances, and diverse marine organisms have the evolved the capacity to diminished the direct and indirect damaging effects of environmental ultraviolet radiation by synthesis and accumulation of MAAs. In this study, we manufactured a radiofrequency (RF) generation device and applied to microalgal culture. $0.35{\pm}0.05$ mHz of RF was supplied to culture vessel for Chlamydomonas sp. and samples were harvested at the designated time intervals (1, 0.5, 1 and 2 hr). MAAs biosynthetic genes, dehydroquinate synthase homolog (DHQS-like) and nonribosomal peptide synthetase homolog (NRPS-like), were cloned from Chlamydomonas sp. and their gene expressions under the RF exposure were analyzed using qRT-PCR. DHQS-like and NRPS-like gene expressions of Chlamydomonas sp. exposed to RF were increased 1.46 and 1.19 fold at 1 hr, respectively. These results means that DHQS-like and NRPS-like genes can be good biomarker candidates for diagnosis of MAAs biosynthesis in the Chlamydomonas sp.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.28 no.2
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• pp.57-62
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• 2018

In this study, we investigated the impurity effect of $Ga_2O_3$ doped thin film by simple doping method using Mg acetate solution. Both undoped $Ga_2O_3$ thin films and Mg-doped $Ga_2O_3$ thin films were grown on Si substrates at 600 and $900^{\circ}C$ for 30 minutes by means of a customized MOCVD method. As a result of the surface analysis, there were no obvious morphological differences by Mg impurity implantation. The surface of the thin film grown at $900^{\circ}C$ was rougher than those grown at $600^{\circ}C$ and polycrystallization was achieved. As a result of the optical property analysis, in the case of the doped sample, the overall emission peak was red shifted and the UV radiation intensity was increased. As a result of the I-V curve, the leakage current of the $600^{\circ}C$ growth thin film decreased by the Mg impurity and the photocurrent of the growth thin film of $900^{\circ}C$ increased.

• Journal of Conservation Science
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• v.36 no.5
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• pp.430-439
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• 2020

This study focused on analyzing solid brown cosmetic residues that were excavated from the tomb of the Hwahyeop princess. The cosmetics had been buried in 1752 in Cheonghwa Baekja (small porcelain jars) within a Huigwakham (a stone box sealed with lime). A literature search and chemical analyses of the relics were conducted at the National Palace Museum of Korea. Based on the results of these analyses, raw materials and manufacturing methods for reproduction of the cosmetic were selected and then cream-form cosmetics were prepared. Aging tests using heat, ultraviolet (UV) radiation, and CO₂ were carried out to emulate the deterioration of the excavated cosmetics. Further chemical analyses and functionality tests were performed to evaluate changes from the tests and the effect as a cosmetic. As heat aging progressed, among the reproduced cosmetics, the one which has a high proposition of oil showed a color difference value of 32; the oxidation of oils involved chemical changes in O-H and C=C groups. As the cosmetic cream deteriorated under UV aging, the pH value became acidic. The result of the functional coverage test of the reproduced cosmetic cream was lower than the standard coverage ratio of modern cosmetics.