• Journal of Food Hygiene and Safety
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• v.32 no.1
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• pp.20-26
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• 2017

Foodborne disease outbreaks associated with produces have been increasing in occurrence worldwide. This study investigated microbial contamination levels on thirteen kinds of agricultural products from farms stage to evaluate potential hazards associated with foodborne illness. A total of 1,820 samples were collected in major cultivating area from 2013 through 2015, and analyzed to enumerate aerobic bacterial counts, coliforms/E. coli, Bacillus cereus and Staphylococcus aureus. In addition, the prevalence study for four kinds of microorganisms (Escherichia coli, E. coli O157:H7, Salmonella spp. and Listeria monocytogenes) was performed on each sample. Aerobic bacterial counts ranged from 0.01 to 7.18 log CFU/g, with the highest bacterial cell counts recorded for watermelon. Coliforms were detected in 651 samples (35.8%) with a minimum of 0.01 log CFU/g and a maximum of more than 5 log CFU/g. B. cereus was detected in 169 samples (9.3%) ranging from < 0.01 to 2.48 log CFU/g among total samples analyzed. S. aureus was detected in 14 samples (0.7%) with a minimum of 0.01 log CFU/g and a maximum of 1.69 log CFU/g. E. coli was detected in 101 samples (5.5%) among 1,820 samples. E. coli O157:H7, Salmonella spp. and L. monocytogenes were not detected in any of the samples. The microbial contamination levels of several agricultural products determined in this study may be used as the fundamental data for microbiological risk assessment (MRA).

• Journal of Korean Society of Environmental Engineers
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• v.30 no.9
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• pp.961-972
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• 2008

In 2004, total emissions of Greenhouse Gases(GHGs) in Korea was estimated to be about 590 million metric tons, which is the world's 10th largest emissions. Considering the much amount of nation's GHG emissions and growing nation's position in the world, GHG emissions in Korea should be reduced in near future. The CO$_2$ emissions from two sub-sections of energy sector in Korea, such as thermal power plant and industry section(including manufacturing and construction industries), was about 300 million metric tons in 2004 and this is 53.3% of total GHG emissions in Korea. So, the mitigation of CO$_2$ emissions in these two section is more important and more effective to reduce the nation's total GHGs than any other fields. In addition, these two section have high potential to qualitatively and effectively apply the CCS(Carbon Capture and Storage) technologies due to the nature of their process. There are several CCS technologies applied to these two section. In short term, the chemical absorption technology using amine as a absorbent could be the most effectively used. In middle or long term, pre-combustion technology equipped with ATR(Autothermal reforming), or MSR-$H_2$(Methane steam reformer with hydrogen separation membrane reactor) unit and oxyfuel combustion such as SOFC+GT(Solid oxide fuel cell-Gas turbine) process would be the promising technologies to reduce the CO$_2$ emissions in two areas. It is expected that these advanced CCS technologies can reduce the CO$_2$ avoidance cost to $US 8.5-43.5/tCO$_2$. Using the CCS technologies, if the CO$_2$ emissions from two sub-sections of energy sector could be reduced to even 10% of total emissions, the amount of 30 million metric tons of CO$_2$ could be mitigated.

• Journal of Applied Biological Chemistry
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• v.52 no.4
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• pp.180-186
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• 2009

Whole plants of Vitex rotundifolia were extracted for 2 days with methylene chloride ($CH_2Cl_2$) followed by extraction of the residue for an additional 2 days. The same procedure was also applied using methanol (MeOH). The two crude extracts were combined and partitioned between $CH_2Cl_2$ and $H_2O$. The organic layer was further partitioned between n-hexane and 85% aq. MeOH, and the aqueous layer was also further fractionated with n-BuOH and $H_2O$, successively. From the 85% aq. MeOH fraction, one compound was isolated through the repeated HPLC. According to the results of physicochemical data including NMR and MS, the chemical structure of the compound was determined as artemetin (1). The antiproliferative effects of the crude extracts, fractions, and compound against HT1080, AGS, MCF-7 and HT-29 human cancer cells were compared with the control by using MTT assay. In the comparative analysis, the 85% aq. MeOH fraction exhibited the strongest antiproliferative effects on human cancer cell lines in a dose-dependent manner (p<0.05). In addition, exposure of compound 1 isolated from 85% aq. MeOH fraction led to strong antiproliferative effect in HT1080 cancer cell lines. These results suggest that the extracts and compound isolated from V. rotundifolia may be used as potential chemopreventive and chemotherapeutic agents.

• Journal of Animal Science and Technology
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• v.49 no.2
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• pp.269-278
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• 2007

This study was performed to measure the pH, proximate composition, physicochemical properties, changes of protein bands, Hunter color values and endpoint cooking temperature of chicken leg and breast muscles during cooking from 64 to 74℃ with 2℃ increments. Chicken leg had higher pH, moisture and fat contents (%) and lower protein solubility(P<0.05) than chicken breast. Although the cooking losses(CLs, %) of chicken muscles increased with increased cooking temperature, the addition of 2% salt did not affect CL. The redness values of chicken leg without 2% salt were higher than chicken breast, however, the addition of 2% salt reduced the differences of the redness. Protein solubility decreased with increased cooking temperatures and were not affected by the addition of salt, and no further changes were observed higher than 68℃. Protein bands having the molecular weights of 66 and 54kDa were disappeared in the chicken leg at the cooking temperatures of 66～70℃, whereas 66, 54 and 34kDa in the chicken breast. These protein bands could be used potential indicators to determine the endpoint cooking temperature in chicken muscles.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.11
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• pp.1007-1018
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• 2009

Hydrocyclone is widely used in industry, because of its simplicity in design, high capacity, low maintenance and operational cost. The separation action of a hydrocyclone treating particulate slurry is a consequence of the swirling flow that produces a centrifugal force on the fluid and suspended particles. In spite of hydrocyclone have many advantage, the application for treatment of urban stormwater case study were rare. We conducted a laboratory scale study on treatable potential of micro particles using hydrocyclone filter (HCF) that was a combined modified hydrocyclone with perlite filter cartridge. Since it was not easy to use actual storm water in the scaled-down hydraulic model investigations, it was necessary to reproduce ranges of particles sizes with synthetic materials. The synthesized storm runoff was made with water and addition of particles; ion exchange resin, road sediment, commercial area manhole sediment, and silica gel particles. Experimental studies have been carried out about the particle separation performance of HCF-open system and HCF-closed system. The principal structural differences of these HCFs are underflow zone structure and vortex finder. HCF was made of acryl resin with 120 mm of diameter hydrocyclone and 250 mm of diameter filter chamber and overall height of 800 mm. To determine the removal efficiency for various influent concentrations of suspended solids (SS) and chemical oxygen demand (COD), tests were performed with different operational conditions. The operated maximum of surface loading rate was about 700 $m^3/m^2$/day for HCF-open system, and 1,200 $m^3/m^2$/day for HCF-closed system. It was found that particle removal efficiency for the HCF-closed system is better than the HCF-open system under same surface loading rate. Results showed that SS removal efficiency with the HCF-closed system improved by about 8~20% compared with HCF-open system. The average removal efficiency difference for HCF-closed system between measurement and CFD particle tracking simulation was about 4%.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.7
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• pp.514-520
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• 2014

In this study, the production potential of alternative coagulant ($Al_2(SO_4)_3$ solution) having the identical coagulation activity with respect to the commercial coagulant was investigated. The raw material of alternative coagulant was a spent catalyst including aluminium (waste activated alumina) generated in the manufacturing process of the polymer. The alternative coagulant was produced through a series of processes: 1) intense heat and grinding, 2) chemical polymerization and substitution with $H_2SO_4$ solution, 3) dissolution and dilution and 4) settling and separation. To determine the optimal operating conditions in the lab-scale autoclave and dissolver, the content of $Al_2O_3$ in alternative coagulant was analyzed according to changes of the purity of sulfuric acid, reaction temperature, injection ratio of sulfuric acid and water in the dissolver. The results showed that the alternative coagulant having the $Al_2O_3$ content of 7~8% was produced under the optimal conditions such as $H_2SO_4$ purity of 50%, reaction temperature of $120^{\circ}C$, injection ratio of $H_2SO_4$ of 5 times and injection ratio of water of 2.3 times in dissolver. In order to evaluate the coagulation activity of the alternative coagulant, the Jar-test was conducted to the effluent in aerobic reactor. As a result, in both cases of Al/P mole of 1.5 and 2.0, the coagulation activity of the alternative coagulant was higher than that of the existing commercial coagulant. When the production costs were compared between the alternative and commercial coagulant through economic analysis, the production cost reduction of about 50% was available in the case of the alternative coagulant. In addition, it was identified that the alternative coagulant could be applied at field wastewater treatment plant without environmental problem through ecological toxicity testing.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.6
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• pp.590-598
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• 2005

An adequate method to identify chromium separation, Cr(III) and Cr(VI), in water samples were studied by using High Performance Liquid Chromatography(HPLC) coupled with Inductively Coupled Plasma Mass Spectometer(ICP-MS) equipped with Dynamic Reaction Cell(DRC). The characteristic distribution of Cr(III) and Cr(VI) in the raw water taken at the six water intake stations in Seoul, was analyzed by the method developed by the authors. The chromium species separated by HPLC was isocratically conducted by using tetrabutylammonium phosphate monobasic(1.0 mM TBAP), ethylenediaminetetraacetic acid(0.6 mM EDTA) and 2% v/v methanol as the mobile phase. 5% v/v methanol was used as flushing solvent. A reactive ammonia($NH_3$) gas was used to eliminate the potential interference of $ArC^+$. Several Parameters such as solvent ratio, pH, flow rate and sample injection volume were optimized for the successful separation and reproducibility. Although it has been reported thai the separation sensitivity of Cr(III) is superior to that of Cr(VI), the authors observed Cr(VI) was more sensitive than Cr(III) when ammonia($NH_3$) gas was used as the reaction gas. It took less than 3 minutes to analyze chromium species with this method and the estimated detection limits were $0.061\;{\mu}g/L$ for Cr(III) and $0.052\;{\mu}g/L$, for Cr(VI). According to the results from the analysis on chromium species in the raw water of the six intake stations, the concentrations of Cr(III) ranged from 0.048 to $0.064\;{\mu}g/L$(ave. $0.054\;{\mu}g/L$) while that of Cr(VI) ranged from 0.014 to $0.023\;{\mu}g/L$(ave. $0.019\;{\mu}g/L$). Recovery ratio was very high($90.1{\sim}94.1%$). There were two or three times more Cr(III) than Cr(VI) in the raw water.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.33 no.4
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• pp.263-267
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• 2007

Parabens are used in nearly all types of cosmetics and toiletries because they are formulated well and have broad spectrum of activity, interness, low costs and excellent chemical stability in relation to pH. 2-phenoxyethanol and chlorphenesin are common preservatives which are usually used in combination with parabens in cosmetics. Toxicity of parabens is generally low but application of parabens to damaged or broken skin has resulted in sensitization. Moreover, the possibility of their estrogenic potential, anesthetic effects and reproductive toxicity has been reported. Consequently there are some regulations in use of parabens. And the maximum permitted concentrations of chlorphenesin and 2-phenoxyethanol in cosmetic products are authorized by the same reasons. So it is important to control and estimate the amount of parabens in products. In this article, we proposed a valid method for the simultaneous determination of 8 preservatives including parabens in a short time using ultra performance liquid $chromatography^{TM}\;(UPLC^{TM})$. Separation of eight components was achieved in less than 10 min and resolutions were reasonable (USP resolution ${\geqq}\;2$). And limit of detection and quantification were evaluated. The method was suitably validated for specificity, linearity, precision (repeatability, intermediate precision) and accuracy for assay (recovery) based on International conference on harmonisation (ICH) guideline. The method was applicable to analysis of preservatives in cosmetic products.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.7
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• pp.958-965
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• 2016

The objective of this study was to evaluate the antioxidant activity of green tea seed shell as an industrial byproduct. Green tea seed shell extract (GTSSE) was obtained by ethanol extraction, and the yield was $1.4{\pm}0.22%$. The radical scavenging activities [1,1-diphenyl-picrylhydrazyl and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid)], xanthine oxidase inhibition activity, and reducing power of GTSSE dose-dependently increased. To estimate the neuroprotective effect of GTSSE, viability was tested in HT22 mouse hippocampal cells. GTSSE treatment induced cytotoxicity at a concentration higher than $100{\mu}g/mL$ but not at a concentration lower than $50{\mu}g/mL$. Using this optimal concentration range, GTSSE treatment significantly increased cell viability in $H_2O_2$-treated HT22 cells. Further, GTSSE treatment increased superoxide dismutase activity and decreased the malonaldehyde level, a product of lipid peroxidation, in HT22 cells. Therefore, these results indicate that green tea seed shell extract may be useful for the development of antioxidant materials and have potential activity to prevent and treat neuro-degenerative diseases such as Alzheimer's disease.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.1
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• pp.39-45
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• 2009

Statement of problem: Recently precalcification treatment has been studied to shorten the period of the implant. Purpose: This study was performed to evaluate the effect of precalcification treatment of $TiO_2$ Nanotube formed on Ti-6Al-4V Alloy. Material and methods: Specimens of $20{\times}10{\times}2\;mm$ in dimensions were polished sequentially from #220 to #1000 SiC paper, ultrasonically washed with acetone and distilled water for 5 min, and dried in an oven at $50^{\circ}C$ for 24 hours. The nanotubular layer was processed by electrochemical anodic oxidation in electrolytes containing 0.5 M $Na_2SO_4$ and 1.0 wt% NaF. Anodization was carried out using a regulated DC power supply (Kwangduck FA, Korea) at a potential of 20 V and current density of $30\;㎃/cm_2$ for 2 hours. Specimens were heat-treated at $600^{\circ}C$ for 2 hours to crystallize the amorphous $TiO_2$ nanotubes, and precalcified by soaking in $Na_2HPO_4$ solution for 24 hours and then in saturated $Ca(OH)_2$ solution for 5 hours. To evaluate the bioactivity of the precalcified $TiO_2$ nanotube layer, hydroxyapatite formation was investigated in a Hanks' balanced salts solution with pH 7.4 at $36.5^{\circ}C$ for 2 weeks. Results: Vertically oriented amorphous $TiO_2$ nanotubes of diameters 48.0 - 65.0 ㎚ were fabricated by anodizing treatment at 20 V for 2 hours in an 0.5 M $Na_2SO_4$ and 1.0 NaF solution. $TiO_2$ nanotubes were composed with strong anatase peak with presence of rutile peak after heat treatment at $600^{\circ}C$. The surface reactivity of $TiO_2$ nanotubes in SBF solution was enhanced by precalcification treatment in 0.5 M $Na_2HPO_4$ solution for 24 hours and then in saturated $Ca(OH)_2$ solution for 5 hours. The immersion in Hank's solution for 2 weeks showed that the intensity of $TiO_2$ rutile peak increased but the surface reactivity decreased by heat treatment at $600^{\circ}C$. Conclusion: This study shows that the precalcified treatment of $TiO_2$ Nanotube formed on Ti-6Al-4V Alloy enhances the surface reactivity.