• The Korean Journal of Food And Nutrition
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• v.31 no.2
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• pp.229-235
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• 2018

Ramie (Boehmeria nivea M.) has been used for fiber materials in Korea traditionally, but in recent years, the concern with ramie leaves for the food industry such as tteok (a kind of Korean rice cake) industry has been increasing, so a study for eatable ramie is required for the expansion of ramie consumption. Moreover, the ramie varieties for the food industry are not established, so the natural species are cultivated in general; therefore, it is very important to select the ramie varieties for the food industry such as rice cakes, tea, beverage and so on. This study was undertaken to compare the physiochemical properties among 9 ramie lines selected in the Yeonggwang-gun Agricultural Technology Center to select the eatable ramie varieties for the food industry. The contents of the protein among 9 ramie lines was 6.21~7.56% and had the highest content in the YG55. The folic acid (folate) and vitamin C content had varying differences among the 9 lines; the content of folate showed $771.52{\sim}1,978.84{\mu}g%$, that of vitamin C showed 149.42~275.34 mg%. The ACE inhibitory activity appeared to be the highest in YG88 (21.5%) among the 9 ramie varieties tested.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.32 no.2 s.57
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• pp.99-103
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• 2006

Natural essential oils showed anti-microbial activity on relatively broad spectrum of bacterial and fungal species. These materials had much more intensive anti-microbial activities than synthetic preservatives on C. albicans, A niger, and P. acnes, especially. In the experimental group, anti-microbial activity was order of tea tree oil (from Melaleuca alternifolia) > methylparaben > phytoncide (from Chamaecyparis obtusa). Also, natural essential oils had anti-oxidative and anti-inflammatory effects. These results suggest that natural essential oils can be useful as good cosmetic ingredients such as natural preservatives and anti-oxidants.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.387-387
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• 2013

Currently, the flash memory and the dynamic random access memory (DRAM) have been used in a variety of applications. However, the downsizing of devices and the increasing density of recording medias are now in progress. So there are many demands for development of new semiconductor memory for next generation. Magnetic random access memory (MRAM) is one of the prospective semiconductor memories with excellent features including non-volatility, fast access time, unlimited read/write endurance, low operating voltage, and high storage density. MRAM is composed of magnetic tunnel junction (MTJ) stack and complementary metal-oxide semiconductor (CMOS). The MTJ stack consists of various magnetic materials, metals, and a tunneling barrier layer. Recently, MgO thin films have attracted a great attention as the prominent candidates for a tunneling barrier layer in the MTJ stack instead of the conventional Al2O3 films, because it has low Gibbs energy, low dielectric constant and high tunneling magnetoresistance value. For the successful etching of high density MRAM, the etching characteristics of MgO thin films as a tunneling barrier layer should be developed. In this study, the etch characteristics of MgO thin films have been investigated in various gas mixes using an inductively coupled plasma reactive ion etching (ICPRIE). The Cl2/Ar, CH3OH/Ar, and CH4/Ar gas mix were employed to find an optimized etching gas for MgO thin film etching. TiN thin films were employed as a hard mask to increase the etch selectivity. The etch rates were obtained using surface profilometer and etch profiles were observed by using the field emission scanning electron microscopy (FESEM).

• Restorative Dentistry and Endodontics
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• v.38 no.4
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• pp.241-247
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• 2013

Objectives: The aim of this study was to determine the effect of epigallocatechin gallate (EGCG) on the shear bond strength of composite resin to bleached enamel. Materials and Methods: Ninety enamel surfaces of maxillary incisors were randomly divided into 9 groups as follows: G1: control (no bleaching); G2: bleaching; G3: bleaching and storage for seven days; G4 - 6: bleaching and application of 600, 800 and 1,000 ${\mu}mol$ of EGCG-containing solution for 10 minutes, respectively; G7 - 9: bleaching and application of 600, 800 and 1,000 ${\mu}mol$ of EGCG-containing solution for 20 minutes, respectively. The specimens were bleached with 30% hydrogen peroxide gel and a composite resin cylinder was bonded on each specimen using a bonding agent. Shear bond strength of the samples were measured in MPa. Data was analyzed using the two-way ANOVA and Tukey HSD tests (${\alpha}$ = 0.05). Results: The maximum and minimum mean shear bond strength values were observed in G1 and G2, respectively. Time and concentration of EGCG showed no significant effects on bond strength of the groups (p > 0.05). Multiple comparison of groups did not reveal any significant differences between the groups except for G2 and all the other groups (p < 0.05). Conclusions: There is a significant decrease in bond strength of composite resin to enamel immediately after bleaching. A delay of one week before bonding and the use of EGCG increased bond strength of composite resin to bleached enamel.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.4
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• pp.584-592
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• 2022

In this paper, a study was conducted to improve self-healing and strength properties using sodium acetate. The developed inorganic-organic self-healing materials and recycled sodium acetate were manufactured to evaluate self-healing and permeability reduction properties. As a result of the experiment with recycled sodium acetate, the compressive strength of the material prepared with anhydrous and trihydrate at a ratio of 7:4 was higher than that of the mixture using anhydrous. It was confirmed that the compressive strength was improved by 3~7 %. In addition, the maximum permeability reduction rate was 92.6 %, which satisfied the self-healing properties.

• Nutrition Research and Practice
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• v.17 no.1
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• pp.91-102
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• 2023

BACKGROUND/OBJECTIVES: This study examines life stress, dietary attitudes, and snacking frequency for college students living in Seoul and Gyeonggi Province. The purpose of this study is to assist college students feeling stressed by offering desirable dietary attitudes and choices of the appropriate snacks by providing educational materials that offer appropriate nutrition education and nutritional information. SUBJECTS/METHODS: A survey was conducted on a total of 600 college students aged 19-29-year-olds living in Seoul and Gyeonggi Province (234 male students and 366 female students). Collected data were analyzed using SPSS WIN 28.0 program. RESULTS: Life stress among college students did not differ significantly between the genders. Male students were more stressed about lover (P < 0.01), while female students were more stressed about value problems (P < 0.01) and future problems (P < 0.05). Dietary attitude ratings were 3.1 for both male and female students with no significant difference. The overall snacking frequency was 4.1 times/day-4.2 times/day for male students and 4.0 times/day for female students-thus, there was no significant difference. Male students consumed 'beverage' (P < 0.01) more frequently than female students. Life stress and snacking were positively correlated for 'biscuit/cookie,' 'chip,' 'cereal,' 'juice/smoothie,' 'café americano,' 'café latte,' 'tea,' 'jelly,' 'chocolate,' 'rice cake,' 'milk,' 'flavored milk,' and 'ice cream' among male students. Among female students, life stress and snacking were positively correlated with 'cereal,' 'caramel,' and 'soymilk,' and negatively correlated for 'biscuit/cookie' and 'carbonated drink.' CONCLUSIONS: College students should manage their stress by identifying its causes and learning how to deal with stressful situations. Additionally, providing them with proper nutrition education based on the correct nutritional information is essential for promoting good food attitudes and snacking behaviors.

• The Journal of Advanced Prosthodontics
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• v.15 no.4
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• pp.189-201
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• 2023

PURPOSE. The aim of this study was to investigate the mechanical properties of three-dimensional (3D) printed denture base resin incorporating microcapsules containing plant essential oils. MATERIALS AND METHODS. Denture base specimens containing up to 3% w/v essential oil microcapsule powders (MCPs), i.e., eucalyptus, geranium, lavender, menthol, and tea tree, in two resins (Detax and NextDent 3D+) were 3D printed using two printers (Asiga and NextDent 5100). The dispersion and interaction of the MCPs in the resin were assessed by SEM while the mechanical properties of the incorporated denture base including flexural strength (MPa), flexural modulus (MPa), Vickers hardness (VHN), and surface roughness (Ra) were also subsequently evaluated. Statistical analysis of any differences in mean values was determined using a two-way ANOVA with Tukey's post hoc testing (α = .05). RESULTS. The spherical shape of the MCPs was maintained during the mixing and polymerization/printing process. However, the Detax-Asiga group showed significant agglomeration of the MCPs even at the lowest MCP concentration levels (0.5% w/v). Overall, as the microcapsule concentration increased, the mean flexural strength decreased, though the menthol MCP groups remained compliant with the ISO standard. The flexural modulus and harness remained relatively unchanged, and the flexural modulus complied with the ISO standard regardless of the MCP concentration. Surface roughness increased with the addition of the MCPs but also remained below that required for clinical acceptance. CONCLUSION. Incorporation of microencapsulated plant essential oils into 3D printed denture base resin was successfully achieved. While incorporation negatively influenced flexural strength and surface roughness, little effect on flexural modulus and Vickers hardness was demonstrated.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.37 no.4
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• pp.347-350
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• 2011

Biofilms are surface-attached microbial communities with phenotypic and biochemical properties distinct from free-living planktonic cells. Biofilm bacteria show much greater resistance than planktonic counterparts and much higher concentration of biocide is needed to treat biofilms compared to the dosage used for planktonic bacteria. As a result, alternative strategies or more effective agents exhibiting activity against biofilm-producing micro-organisms are of great interest. Therefore, we turned our attention to control of biofilm of S. aureus. The aims of this research are to investigate substances which inhibit the formation of biofilm by S. aureus and to suggest effective materials for controlling skin problems. We coated slide glasses with human placental collagen and the coverslip was incubated with test materials and bacteria. The coverslip was stained with crystal violet and we measured optical density of each sample. The biofilm inhibitory activity was calculated by crystal violet staining degrees. In this study, S. aureus ATCC 6538 was used as test organism. Our results show that both water soluble and insoluble Hinoki cypress polysaccharide strongly inhibited biofilm formation. Whereas, green tea and sunset hibiscus root extract promoted biofilm. Xylitol showed a concentration dependent effect; high concentration (3 % and 5 %) of xylitol reduced biofilm while promoted biofilm formation at a concentration of 1 %. These results support that Hinoki cypress polysaccharide and xylitol have ability to suppress biofilm formation.

• Journal of Bio-Environment Control
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• v.5 no.1
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• pp.23-33
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• 1996

This study was performed to induce a quality improvement and standardization of materials used for greenhouse. For this purpose, physical and mechanical properties of agricultural films for greenhouse were measured by kinds and thickness of the films. The properties are composed of impact, tensile, tear propagation strength and light transmittance. The results were summarized as follows. 1. At the impact test result of the falling dart, the thicker the film, the greater the impact strength of soft film. The impact weight at 50 percents is from 158g to 213g and the strength of low density polyethylene(LDPE) film is higher than the rest of any other films. 2. Seeing the leveling of the impact rupture, maximum impact weight which was ruptured very little ranges from 62g to 192g. The impact strength of 0.1mm films was higher than that of 0.05mm as from 1.8 to 3.2 times. 3. Tensile weight covers from 0.95kg to 2.22kg in the test materials, and the weight of lengthwise film is larger than that of width. LDPE film has high value of tensile weight. Elongation range is from 345 to 102 percent and lengthwise elongation is greater than width as much as from 1.4 to 2.7 times. 4. Tea. propagation strength ranges from 80.5kg/cm to 121.7kg/cm, and unlike which of LDPE film has high value, EVA film has low value in the films tested. The width strength is higher than the lengthwise. 5. The light transmittance of the soft film is about 78-92 percent in the range of ultraviolet ray, but has high value in the visible ray range.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.4
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• pp.549-556
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• 2005

Response surface methodology (RSM) was applied in steaming and roasting processes of Polygonatum odoratum roots in order to monitor hypoglycemic components and sensory property. In steaming and roasting processes based on the central composite design with variations in steaming time $(60\~180\;min)$, roasting temperature $(110\~150^{\circ}C)$ and roasting time $(10\~50\;min)$, coefficients of determinations $(R^2)$ were 0.8691 (p<0.05), 0.8253 (p<0.l0), 0.8727 (p<0.05), 0.8706 (p<0.05) and 0.8316 (p<0.10) in soluble solid, stigmasterol, $\beta-sitosterol$, hypoglycemic component (total), and overall acceptability, respectively. The maximum value of soluble solid was $71.47\%$ in 65.24 min of steaming time, $126.93^{\circ}C$ of roasting temperature and 37.58 min of roasting time. The maximum value of hypoglycemic component (total) was $764.10\;{\mu}g/g$ in 107.76 min, $117.78^{\circ}C$ and 14.70 min. Meantime, the maximum value of overall acceptability was 6.89 in 126.04 min, $115.79^{\circ}C$ and 43.93 min. The predicted values in optimum conditions for hypoglycemic components and sensory property were in good agreement with experimental values.