• Food Science and Preservation
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• v.20 no.4
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• pp.546-553
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• 2013

In this study, we examined the antioxidant activity of the Sumaeyaksuk (Artemisia argyi) tea extracts from different pre-treatment and extraction methods. Sumaeyaksuk was sun-dried for 3.5 days (control, RC) and aged at a temperature of $60^{\circ}C$ for 3.5 days (HA), 7 days (HB), and 14 days (HC), respectively. Each sample was extracted in $60^{\circ}C$ and $95^{\circ}C$ hot water for 2 minutes. The soluble solids content of HA from the $60^{\circ}C$and $95^{\circ}C$ hot water extraction were $0.52{\pm}0.18%$ and $0.92{\pm}0.18%$, respectively. The soluble solids content was increased by the higher extraction temperature. The reducing sugar content of RC was $9.55{\pm}0.18mg/g$ in the $95^{\circ}C$ extraction, which was significantly higher than in the $60^{\circ}C$ extracted sample. However, the reducing sugar content did not show a remarkable difference based on aging periods. The total phenolic compound content of the $95^{\circ}C$ extracted samples was $3.36{\pm}0.13{\sim}9.88{\pm}0.23mg/g$, which was significantly higher than that of the $60^{\circ}C$ extracted sample. The ABTS radical scavenging activity of the $60^{\circ}C$ extracted RA and HA samples were 35.63% and 95.10%, respectively. Moreover, the radical scavenging activity increased to 63.35% and 96.78%, respectively, in the $95^{\circ}C$ extracted samples. As a result of the high temperature, the extracted sample showed an increase in the FRAP. In the RC sample, the FRAP was two times higher in the $95^{\circ}C$ extracted sample ($181.28{\pm}2.90{\mu}M$) than in the $60^{\circ}C$ extracted sample ($83.88{\pm}0.43{\mu}M$).

• Journal of Environmental Health Sciences
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• v.22 no.1
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• pp.36-44
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• 1996

A comparison was made of two detection methods(UV absorbence detection and fluorescence detection with pre-column derivatization, with trifluoroacetic acid) coupled with HPLC for the simultaneous determination of aflatoxin $B_1, B_2, G_1$ and $G_2$. A good separation of the four aflatoxins was achieved on a reversed-phase $C_{18}$ column (30 cm x 3.9 mm) with methanol-acetonitrile-water(20+20+60) for absorbence detection or acetonitrile-water(25+75) for fluorescence detection at the flow rate of 1.0 ml/min. The calibration graphs were linear over the ranges 100 ppb-1 ppm for $B_1/G_1$ and 30~300 ppb for $B_2/G_1$ with absorbence detection, and 1~500 ppb for $B_1/G_1$ and 0.3~150 ppb for $B_2/G_2$ with fluorescence detection. The correlation coefficients were greater than 0.94 and 0.99 for absorbance detection and for fluorescence detection, respectively. The detection limit was 100 ng for $B_1/G_1$ and 30 ng for $B_2/G_2$ with absorbence detection, and 1 ng for $B_1/G_1$ and 0.3 ng for $B_2/G_2$ with fluorescence detection. Recovery rates of aflatoxin $B_1, B_2, G_1$ and $G_2$ added to yeast-extract sucrose broth medium were 66.6%, 59.4%, 67.5% and 59.2%, respectively, for absorbence detection and 82.9%, 71.5%, 80.0% and 69.3%, respectively, for fluorescence detection. The four aflatoxins in culture medium were quantitatively detected by the two methods. The aflatoxins in the rice sample were not detected the absorbence detection method, but were below 10 ppb using the fluorescence detection method. Analysis of aflatoxins by both the absorbence and fluorescence methods coupled with HPLC showed acceptable linearity and good recovery. The absorbence detection was less timeconsuming and safer for treatment. The fluorescence detection was more elective and sensitive though elevated $B_1$ and $G_1$ contents were determined from the TFA-induced conversion of $B_1$ to $B_{2a}$ and $G_1$ to $G_{2a}$.

• Korean Journal of Materials Research
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• v.24 no.6
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• pp.310-318
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• 2014

In this experiment, a highly porous scaffold of biphasic calcium phosphate (BCP) was prepared using the spongereplica method. The BCP scaffold was coated with 58S bioactive glass (BG) and sintered for a second time. The resulting scaffold was coated with gelatin (Gel) and cross-linked with [3-(3-dimethyl aminopropyl) carbodiimide] and N-Hydroxysuccinamide (EDC-NHS). The initial average pore size of the scaffold ranged from 300 to $700{\mu}m$, with more than 85 % porosity. The coating of BG and Gel had a significant effect on the scaffold-pore size, decreasing scaffold porosity while increasing mechanical strength. The material and surface properties were evaluated by means of several experiments involving scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) and X-ray diffraction (XRD). Cytotoxicity was evaluated using MTT assay and confocal imaging of MC3T3-E1 pre-osteoblast cells cultured in vitro. Three types of scaffold (BCP, BCP-BG and BCP-BG-Gel) were implanted in a rat skull for in vivo evaluation. After 8 weeks of implantation, bone regeneration occurred in all three types of sample. Interestingly, regeneration was found to be greater (geometrically and physiologically) for neat BCP scaffolds than for two other kinds of composite scaffolds. However, the other two types of scaffolds were still better than the control (i.e., defect without treatment).

• Bulletin of the Korean Chemical Society
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• v.32 no.6
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• pp.2021-2026
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• 2011

AgNPs (silver nanoparticles) has been widely used for the commercial products, which have antimicrobial agent, medical devices, food industry and cosmetics. Despite, AgNPs have been reported as toxic to the mammalian cell, lung, liver, brain and other organs and many researchers have investigated the toxicity of AgNPs. In this study, we investigated toxicity of the AgNPs to the liver cell using metabolomics based on HRMAS NMR (High Resolution Magic Angle Spinning Nuclear Magnetic Resonance) technics, which could apply to the intact tissues or cells, to avoid the sample destruction. Target profiling and multivariative statistical analysis were performed to analyze the 1D $^1H$ spectrum. The results show that the concentrations of many metabolites were affected by the AgNPs in the liver cell. The concentrations of glutathione (GSH), lactate, taurine, and glycine were decreased and most of amino acids, choline analogues, and pyruvate were increased by the AgNPs. Moreover, the levels of the metabolites were recovered upto similar level of metabolites in the normal cell by the pre-treatment of NAC, external antioxidant. The results suggest that the depletion of the GSH by the AgNPs might induce the conversion of lactate and taurine to the pyruvate.

• Korean Journal of Health Education and Promotion
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• v.16 no.1
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• pp.137-148
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• 1999

The necessity of school health promoting projects is well known to many researchers, however, there is a lack of research on the development of strategies for school health programs and the evaluation of the effectiveness of the programs. The results of our previous study in 1996 identified poor eyesight as one of the several health problems among elementary school children in urban areas. The main objective of this study is to develop, implement, and evaluate vision care for elementary school children. The research method utilized a quasi experimental design using non-equivalent group, pre-post comparison. The sample consisted of all second grade children in two elementary schools in Kyung-giProvince. In order to prevent a contamination effect of the vision care program, one school was selected as a control and the other school was selected as a treatment group. The experimental school had 467 children and the control school had 402 children. The visual acuity of children in both group was measured and a survey questionnaire was sent out to parents on the knowledge, attitude, and behavior related to vision care before the program was implemented. The children of the experimental school received the following programs; separate education on proper nutrition and care of eyesight for children and parents, daily eye exercises using video tape, and an essay and poster contest on healthy eyesight. The eye exercise program lasted from March, 1997 to November, 1997. On November, 1997, visual acuity was measured again from children in both schools. The data was analyzed by using SAS statistical package. The results indicate that the children in the experimental group had significantly (p〈0.001) better eyesight than the children in the control group. Also, some of the behavior highly related to the poor eyesight are poor maternal eyesight and watching TV from a short distance. In conclusion, one of the significance of this project is that the vision care program was developed after the need assessment. It will be encouraged in the future that more school health program should be developed after a need assessment. Also, inclusion of family members was important in health promoting projects within a school setting since healthy behavior needs to be reinforced at horne as well as at school.

• Journal of Korean Clinical Nursing Research
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• v.18 no.1
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• pp.126-135
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• 2012

Purpose: This study was aimed to develop a simulation training program of an advanced cardiac life support (ACLS) based on the mastery learning model (Simulation-MLM), and evaluate the effects of the program on critical care nurses. Methods: As an experimental pre-post test with a non-equivalent control group, the study employed convenience sampling of 38 critical care nurses. The experimental group received the Simulation-MLM including a theoretical lecture, formative evaluation, and simulation training, whereas only a theoretical lecture for the control group. The knowledge, self-efficacy, and performance degrees of respondents were measured to verify the effects of the Simulation-MLM. The statistical processing of the collected data utilized the SPSS WIN 17.0 program. Results: After receiving Simulation-MLM, the participants in the experimental group reported higher marks in the knowledge, self-efficacy and performance of ACLS compared with those in the control group. However, both experimental and control groups demonstrated no significant differences in knowledge, self-efficacy and performance. Conclusion: Despite of the limitation of a small sample size, this study was considered meaningful in a sense that it showed a venue for improving ACLS training efficiency. Future research with more distinct treatment differentiation and better adequate outcome variables was warranted in order to prove the effects of a theory-based simulation education.

• Proceedings of KOSOMES biannual meeting
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• 2007.11a
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• pp.35-41
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• 2007

An International Convention on the control of harmful anti-fouling system on ships(AFS Convention) was adopted on 5 October 2001 at Diplomatic Conference in London, and is expected to be presently effectuated with ratification of more than 25-member nations possessing about 25% of total world tonnage. This convention regulates the operation of harmful anti-fouling system and especially prohibits the use of organotin compounds contained in anti-fouling paint. Organotin compounds have a tendency to be easily extracted by specific solvents and have high polarity and low volatility as specific characteristics. This drives us to attempt of going through the process named derivatization that is required in analysis using a gas chromatography(GC). This study was conducted to determine the proper pre-treatment method, ethylation in comparison with hydridization on the analysis of tributyltin in organotin compounds and to verify the application of the method through the experimental analysis practically used anti-fouling paint and painted layer sample of the served ship.

• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.139-141
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• 2005

It is possble to study charge transfer property which is caused by height variation because we can see the organic materials barrier height and STM tip by organic materials energy band gap. Here, we investigated the negative differential resistance(NDR) and charge transfer property of self-assembled 4,4-Di(ethynylphenyl)-2'-nitro-1-(thioacetyl)benzene, which has been well known as a conducting molecule. Self-assembly monolayers(SAMs) were prepared on Au(111), which had been thermally deposited onto pre-treatment($H_{2}SO_{4}:H_{2}O_{2}$=3:1) Si. The Au substrate was exposed to a 1 mM/l solution of 1-dodecanethiol in ethanol for 24 hours to form a monolayer. After thorough rinsing the sample, it was exposed to a $0.1{\mu}M/1$ solution of 4,4-Di(ethynylphenyl)-2'-nitro-1-(thioacetyl)benzene in dimethylformamide(DMF) for 30 min and kept in the dark during immersion to avoid photo-oxidation. After the assembly, the samples were removed from the solutions, rinsed thoroughly with methanol, acetone, and $CH_{2}Cl_{2}$, and finally blown dry with $N_2$. Under these conditions, we measured electrical properties of self-assembly monolayers(SAMs) using ultra high vacuum scanning tunneling microscopy(UHV-STM). The applied voltages were from -1.50 V to -1.20 V with 298 K temperature. The vacuum condition is $6{\times}10^{-8}$ Torr. As a result, we found that NDR and charge transfer property by a little change of height when the voltage is applied between STM tip and electrode.

• Journal of the Korean Home Economics Association
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• v.41 no.11
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• pp.135-150
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• 2003

This research was to verity the effects of ICT teaching method in high school home economics. The research questions for this study were as follows: 1. Is the ICT teaching method effective in increasing students' interest in home economics and consciousness on traditional culture in teaming the unit of ‘Korean traditional culture of home life’？ 2. Is the ICT teaching method effective in improving students' achievement test and performance assessment in teaming the unit of ‘Korean traditional culture of home life’？ This study is carried out with following procedure: developing the homepage and lesson plans for ICT teaching, constructing questionnaire, and testing its reliability, pre-testing, treatment for 8 weeks, and post-testing. Two groups were arranged for 8 weeks experiment from May 7,2001 through June 30,2001. Sixteen hours of ICT teaching and 8 hours of traditional lecture for experiment group whereas 8 hours of ICT teaching and 16 hours of traditional lecture for comparison group were input. SAS program was used for statistical analysis, and independent sample t-test and matched pairs t-test were peformed for answering research questions. The results of this study were as following: 1. Sixteen hours of ICT teaching and 8 hours of traditional lecture for experiment group was effective in increasing consciousness on traditional culture and performance assessment. 2. Eight hours of ICT teaching and 16 hours of traditional lecture for comparison group was not effective in learning home economics. This means that at least 2 hours of ICT teaching is demanding for effective learning. This study concluded that ICT teaching will be effectively applied in high school home economic with well developed ICT teaching materials. And home economics educators should continuously put effort in developing curricular, teaching materials, and teaching methods to raise students' interest in home economics.

• Journal of the Korean Applied Science and Technology
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• v.22 no.4
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• pp.306-314
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• 2005

In this study, spherical $pre-BaTiO_3$ particles are prepared by gelation and aging process in autoclave without catalysts. The (Ba-Ti) gel used as a starting material was prepared by aging mixtures of titanyl acylate with barium acetate aqueous solution([glacial acetic acid (AcOH)]/[titanium isopropoxide (TIP)] 4, [barium acetate]/[TIP] 1) at $45^{\circ}C$ for 48hrs. XRD and SEM results for the (Ba-Ti) gel sample at aging process showed that the gel was formed via aggregation of the fine particles. It seems to be the primary particles of bulk (Ba-Ti) gel amorphous, but the spatial arrangement of barium and titanium in the (Ba-Ti) gel is similar to that in crystalline $BaTiO_3$ particles. From XRD and FT-IR. spectroscopy analysis it was found that the crystal structure of the prepared particles continuously transformed from amorphous to tetragonal as the calcination temperature increased, and crystallized spherical cubic and tetragonal $BaTiO_3$ powder obtained at the very low calcination temperature between $500^{\circ}C$ and $900^{\circ}C$ after 1hrs of heat treatment respectively. According to BET analysis result, final particle have pore structure of ink bottle shape which is produced by aggregation of fine spherical particles with surface area of $280m^2/g$ and average pore size of 130nm.