• Journal of the Society of Cosmetic Scientists of Korea
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• v.44 no.4
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• pp.419-425
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• 2018

In this study, cross-linked collagen gels were successfully prepared with varying of elastic modulus from 0.7 to 17.7 kPa using a chemical cross-linker. Then, human dermal fibroblasts were encapsulated into the porous pores introduced into the gels, and cell growth and behavior were examined by gel's mechanical properties. Specifically, increasing elastic modulus of the gel led to decreases in procollagen synthesis from 47 to 32 ng. In addition, there could be optimum elastic modulus for procollagen production, when the gels were treated with adenosine. However, interestingly, this study discovered that the procollagen production level was not influenced by the elastic modulus of the gel for functional peptide. In conclusion, these results would be highly useful for designing reconstructed skins with varying of elastic modulus to examine functional materials in cosmetics.

• Metals and materials international
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• v.24 no.6
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• pp.1394-1402
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• 2018

This study investigates the mechanism of MnS precipitation on $Al_2O_3-SiO_2$ inclusions during the solidification of non-oriented silicon steel, especially the influence of the phase structures and sizes of the oxides on the MnS precipitation, by scanning electron microscopy and transmission electron microscopy coupled with energy dispersive spectrometry. The investigation results show that MnS tends to nucleate on submicron-sized $Al_2O_3-SiO_2$ inclusions formed by interdendritic segregation and that it covers the oxides completely. In addition, MnS can precipitate on micron-sized oxides and its precipitation behavior is governed by the phase structure of the oxides. The MnS embryo formed in a MnO-containing oxide can act as a substrate for MnS precipitation, thus permitting further growth via diffusion of solute atoms from the matrix. MnS also precipitates in a MnO-free oxide by the heterogeneous nucleation mechanism. Furthermore, MnS is less prone to precipitation in the $Al_2O_3$-rich regions of the $Al_2O_3-SiO_2$ inclusions; this can be explained by the high lattice disregistry between MnS and $Al_2O_3$.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.30 no.1
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• pp.34-41
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• 2019

Objectives: We aimed to compare preterm, neurodevelopmentally disordered and healthy full-term children. Methods: We enrolled 47 children who were born preterm, 40 neurodevelopmentally disordered children, and 80 healthy children as control participants, in order to assess the cognitive functioning and the risk of behavioral problems at the age of 5. Children were assessed using the Korean Wechsler Preschool and Primary Scale of Intelligence-4th edition (K-WPPSI-IV), the Child Behavior Checklist (CBCL), and the Temperament and Character Inventory (TCI). Results: The mean K-WPPSI-IV score of the preterm group was $87.19{\pm}17.36$, which was significantly higher than that of the neurodevelopmental disorder group ($69.98{\pm}28.63$; p<0.001) but lower than that of the control group ($107.74{\pm}14.21$; p<0.001). The cumulative CBCL scores of the preterm children were not significantly different from those of the control group. Additionally, the TCI scores for reward dependence of the preterm children were higher than those of the control group. Conclusion: The cognitive performance of preterm infants was lower than that of healthy full-term infants at the age of 5, and there was an association between slower growth and decreased cognitive ability.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.1
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• pp.115-122
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• 2019

Steel Fiber Reinforced Wet-type Shotcrete improves the quality and stabilizes the tunnel by increasing the shear strength of the natural ground by constructing the concrete which attaches the fresh concrete to the predetermined position from the nozzle. The Steel Fiber Reinforced Wet-type Shotcrete improves and reinforces the strength and dynamic behavior characteristics of concrete to suppress the generation and growth of local cracks by increasing the tensile resistance ability. In addition, Steel Fiber Reinforced Wet-type Shotcrete is a shotcrete that improves tensile strength, bending strength, and crack resistance by dispersing discontinuous short steel fibers evenly in concrete. In this study, compressive strength test and bending strength test of shotcrete of NATM tunnel were measured and rebound reduction rate was measured by varying shotcrete putting pressure to 900 RPM, 1,000 RPM, and 1,100 RPM. Therefore, the data that can be applied to domestic NATM tunnel construction are presented.

• Current Photovoltaic Research
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• v.7 no.3
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• pp.65-70
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• 2019

As a demand of higher power photovoltaic modules, shingled, multi-busbar, half-cell, and bifacial techniques are developed. Multi-busbar module has advantage for large amount of light havesting. And, half-cell is high power module for reducing resistive losses and higher shade tolerance. Recently, researches on multi-busbar is focused on reliability according to adhesion and intermetallic compound between Sn-Pb solder and Ag electrode. And half-cell module is researched to comparing with full-sized cell module for structure difference. In this study, we investigated the factors affecting to efficiency and adhesion of multi-wires half-cell module according to wire thickness, solder thickness, and flux. The results of solar simulator and peel test was that peel strength and efficiency of soldered cell is not related. But samples with flux including high solid material showed high efficiency. The results of FE-SEM and EDX line scan on cross-section between wire and Ag electrode for different flux showed thickness of solder joint between wire and Ag electrode is increasing through solid material increasing. Flux including high solid material would affect to solder behavior on Ag electrode. Higher solid material occurred lower growth of IMC layer because solder permeate to sider of wire ribbon than Ag electrode. And it increased fill factor for high efficiency. In soldering process, amount of solid material in flux and solder thickness are the factor related with characteristic of soldered photovoltaic cell.

• Korean Journal of Materials Research
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• v.29 no.1
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• pp.1-6
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• 2019

Recent industrialization has led to a high demand for the use of fossil fuels. Therefore, the need for producing hydrogen and its utilization is essential for a sustainable society. For an eco-friendly future technology, photoelectrochemical water splitting using solar energy has proven promising amongst many other candidates. With this technique, semiconductors can be used as photocatalysts to generate electrons by light absorption, resulting in the reduction of hydrogen ions. The photocatalysts must be chemically stable, economically inexpensive and be able to utilize a wide range of light. From this perspective, cuprous oxide($Cu_2O$) is a promising p-type semiconductor because of its appropriate band gap. However, a major hindrance to the use of $Cu_2O$ is its instability at the potential in which hydrogen ion is reduced. In this study, gold is used as a bottom electrode during electrodeposition to obtain a preferential growth along the (111) plane of $Cu_2O$ while imperfections of the $Cu_2O$ thin films are removed. This study investigates the photoelectrochemical properties of $Cu_2O$. However, severe photo-induced corrosion impedes the use of $Cu_2O$ as a photoelectrode. Two candidates, $TiO_2$ and $SnO_2$, are selected for the passivation layer on $Cu_2O$ by by considering the Pourbaix-diagram. $TiO_2$ and $SnO_2$ passivation layers are deposited by atomic layer deposition(ALD) and a sputtering process, respectively. The investigation of the photoelectrochemical properties confirmed that $SnO_2$ is a good passivation layer for $Cu_2O$.

• Journal of Microbiology and Biotechnology
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• v.31 no.1
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• pp.51-62
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• 2021

Here, we investigated the prebiotic and antioxidant effects of Actinidia arguta sprout water extract (AASWE) on lipopolysaccharide (LPS)-induced cognitive deficit mice. AASWE increased viable cell count, titratable acidity, and acetic acid production in Lactobacillus reuteri strain and showed a cytoprotective effect on LPS-induced inflammation in HT-29 cells. We assessed the behavior of LPS-induced cognitive deficit mice using Y-maze, passive avoidance and Morris water maze tests and found that administration of AASWE significantly improved learning and memory function. The AASWE group showed antioxidant activity through downregulation of malondialdehyde levels and upregulation of superoxide dismutase levels in brain tissue. In addition, the AASWE group exhibited activation of the cholinergic system with decreased acetylcholinesterase activity in brain tissue. Furthermore, AASWE effectively downregulated inflammatory mediators such as phosphorylated-JNK, phosphorylated-NF-κB, TNF-α and interleukin-6. The major bioactive compounds of AASWE were identified as quercetin-3-O-arabinopyranosyl(1→2)-rhamnopyranosyl(1→6)-glucopyranose, quercetin-3-O-apiosyl(1 → 2)-galactoside, rutin, and 3-caffeoylquinic acid. Based on these results, we suggest that AASWE not only increases the growth of beneficial bacteria in the intestines, but also shows an ameliorating effect on LPS-induced cognitive impairment.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.3
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• pp.47-58
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• 2021

Recently, personal mobility (PM)-related complaints and PM accidents have increased as the number of users soars due to growth in the domestic PM market and the emergence of a number of electric scooter-sharing services. As a result, the need for PM education and practice spaces is emerging as a way to reduce accidents caused by poor PM manipulation and operation. In this study, we analyze the relevant conflict factors in order to come up with a systematic operation and activation plan for PM, and as an alternative, we review and propose how to operate a PM playground and test zone. It is expected that basic data collection and analysis of rudimentary driver behavior through PM playground operations will improve users' operational safety, and various conflicts of interest between users and non-users will be resolved by installing facilities to secure their safety.

• Korean Journal of Community Nutrition
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• v.26 no.3
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• pp.155-166
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• 2021

Objectives: Driven by a growth of single-person households and individualized lifestyles, solo dining in restaurants is an increasingly recognizable trend. However, a research gap exists in the comparison of solo and group diners' menu-decision making processes. Based on the self-control dilemma and the temporal construal theory as a theoretical framework, this study compared the ordering intentions of solo vs. group diners with healthy vs. indulgent (less healthy) entrées. The mediating role of consumption orientation and the moderating role of amount of menu nutrition information were further explored to understand the mechanism and a boundary condition. Methods: A scenario-based online survey was developed using a 2 (dining social context: solo vs. with others) × 3 (amount of menu nutrition information: no nutrition information vs. calories vs. calories/fat/sodium), between-subjects, experimental design. Consumers' level of nutrition involvement was controlled. A nationwide survey data (n = 224) were collected from a crowdsourcing platform in the U.S. Data were analyzed using multivariate analysis of covariance, independent t-test, univariate analysis of covariance, and moderated mediation analyses. Results: Findings reveal that solo (vs. group) diners have less (vs. more) intentions to order indulgent menu items due to a more utilitarian (vs. more hedonic) consumption orientation in restaurant dining. Findings also show that solo (vs. group) diners have more (vs. less) intentions to order healthy menu items when the restaurant menu presented nutrition information including calories, fat, and sodium. Conclusions: The findings contribute to the literature of foodservice management, healthy eating, and consumer behavior by revealing a mechanism and an external stimuli of solo vs. group diners' healthy menu-decision making process in restaurants. Furthermore, the findings provide restauranteurs and health professionals with insights into the positive and negative impacts of menu nutrition labelling on consumers' menu-decisions.

• Korean Journal of Metals and Materials
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• v.49 no.8
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• pp.614-618
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• 2011

Nanopowders of MgO, $Al_2O_3$ and $SiO_2$ were made by high energy ball milling. The rapid sintering of nanostructured $MgAl_2O_4-Mg_2SiO_4$ composites was investigated by a high-frequency induction heating sintering process. The advantage of this process is that it allows very quick densification to near theoretical density and inhibition of grain growth. Nanocrystalline materials have received much attention as advanced engineering materials with improved physical and mechanical properties. As nanomaterials possess high strength, high hardness, excellent ductility and toughness, undoubtedly, more attention has been paid for the application of nanomaterials. Highly dense nanostructured $MgAl_2O_4-Mg_2SiO_4$ composites were produced with simultaneous application of 80MPa pressure and induced output current of total power capacity (15 kW) within 2min. The sintering behavior, gain size and mechanical properties of $MgAl_2O_4-Mg_2SiO_4$ composites were investigated.