• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.3
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• pp.89-95
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• 2022

In this study, glassy carbon coating was performed on the graphite using a phenolic resin and a curing agent was mixed with ethylene glycol as an additive to form the uniform surface. The phenolic resin was dried and cured under the environments of hot air, then converted into a glassy carbon layer by pyrolysis at 500~1,500℃. FTIR, XRD, SEM analysis, and density/porosity/contact angle measurement were performed for characterization of glassy carbon. The pyrolysis temperature for high-quality glassy carbon was optimized to be about 1,000℃. As the content of the additive increased, the effect of reducing surface defects on the coated surface, reduction of porosity, increase of contact angle, and increase of density were investigated in this study. The method of forming a glassy carbon coating layer through an additive is expected to be applicable to graphite coating and other fields.

• Journal of Dental Rehabilitation and Applied Science
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• v.38 no.2
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• pp.71-80
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• 2022

Although low translucency 3 mol% yttria stabilized tetragonal zirconia polycrystal has excellent mechanical properties, it has limited application as a monolithic prosthesis. To improve these optical limitations, translucent zirconia has improved esthetics due to an increase in the cubic phase; however, it is accompanied by a decrease in mechanical properties simultaneously. Lithium disilicate has improved its mechanical properties through crystal size reduction and various heat treatment methods; therefore, its clinical application range is continuously increasing. Translucent zirconia shows a wide distribution of physical properties depending on the yttria content and lithium disilicate according to the size and density of crystal grains. As a result, the indications for translucent zirconia and lithium disilicate are increasing. Therefore, in this literature review, we intend to examine the rationale behind the material selection criteria in clinical situations and considerations for designing fixed dental prostheses including pontic, in particular, by summarizing recent studies.

• The Korea Journal of Herbology
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• v.34 no.1
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• pp.23-31
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• 2019

Objectives : The aim of this study was to investigate the effect for allergic-inflammation of Fritillariae Thunbergii Bulbus (FTB) on HaCaT cells and RBL2H3 cells. Methods : To investigate the effects of FTB for anti-inflammation in HaCaT cells, the cells were pretreated with FTB for 1h and then stimulated with $TNF-{\alpha}/IFN-{\beta}$ for 24h. Then thymus and activation-regulated chemokine (TARC) and Macrophage-derived chemokine (MDC) levels were analyzed with ELISA kit. Also to investigate the effect of skin barrier protein, the cells were treated with FTB of various concentrations, and then cells were harvested, expressions of skin barrier protein were measured with RT-PCR. To investigate the effects of FTB for anti-allergy in RBL2H3 cells, the cells were pre-treated with FTB for 1h, and then stimulated with A23187 for 30 min. ${\beta}$-hexosaminidase, IL-4 and $TNF-{\alpha}$ were measured using cultured media. The cells were harvested to analyze the mechanism of the effect for FTB via Western blot. Results : FTB did not show cytotoxicity in HaCaT and RBL2H3. In HaCaT cells, FTB significantly suppressed the expression of TARC, MDC at a dose-dependent manner and markedly increased formation of the skin barrier proteins. In RBL2H3 cells, FTB decreased release of the ${\beta}$-hexosaminidase, IL-4 and $TNF-{\alpha}$ in RBL2H3 through inhibition of the phosphorylation of JNK and p38, which are include in the signaling mechanism of MAPK Conclusion : These results indicate that FTB has an anti-inflammatory effect on the allergic response through blocking MAPK pathway. This suggest that FTB could be a therapeutic agent for allergic response.

• Korean Journal of Agricultural Science
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• v.49 no.3
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• pp.539-545
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• 2022

The aim of this study was to evaluate the effect of beekeeping by-products added to drinking water on the growth performance and intestinal and fecal microflora of Institute of Cancer Research (ICR) mice. A total of 72 five-week-old ICR mice with an initial body weight (BW) of 24.57 ± 0.60 g were used in a two-week experiment. The four treatment groups were as follows; 1) CON, normal distilled water; 2) T1, CON with 0.7% beehive extract; 3) T2, CON with 0.7% propolis (PRO); and 4) T3, CON with 0.7% royal jelly (RJ). Each treatment consisted of 6 replicate cages with 3 mice per cage. At 0 - 1 week, T3 showed a significantly higher (p < 0.05) body weight gain (BWG) and feed efficiency (G : F) than that of CON. Compared with CON, T2 showed a significantly higher (p < 0.05) BWG and feed intake at 1 - 2 weeks. During the entire period, T2 and T3 showed a significantly higher (p < 0.05) BWG and G : F compared to CON. The amount of Salmonella and Lactobacillus in the large intestine was significantly decreased and increased (p < 0.05) in T2 and T3, respectively, compared to CON. The amount of Escherichia coli in the fecal matter was significantly reduced (p < 0.05) compared to CON in all treatment groups to which beekeeping by-products were added. In conclusion, the addition of PRO or RJ to the drinking water of ICR mice had a positive effect on the growth performance and the intestinal and fecal microflora.

• Korean Journal of Acupuncture
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• v.39 no.2
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• pp.43-53
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• 2022

Objectives : Paeonia lactiflora Pallas (PLP) have been reported to have pharmacological effects such as anti-inflammatory and analgesic. However, it is not yet known whether PLP extract has anti-inflammatory effect on HaCaT cells, human keratinocyte. Methods : To confirm the anti-inflammatory effect of PLP on keratinocyte, TNF-𝛼/IFN-𝛾-stimulated HaCaT cells were used. HaCaT cells were pre-treated with PLP for 1h before stimulation with TNF-𝛼/IFN-𝛾. Then HaCaT cells were stimulated with TNF-𝛼/IFN-𝛾 for 24 h, the cells and media were harvested to measure the inflammatory cytokines levels. Granulocyte-macrophage colony stimulating factor (GM-CSF), monocyte chemoattractant protein-1 (MCP-1), interleukin 1 beta (IL-1𝛽), and TNF-𝛼 were analyzed by enzyme-linked immunosorbent assay (ELISA), and the mRNA expression of thymus and activation-regulated chemokines (TARC), IL-6, and IL-8 were measured by reverse transcription-polymerase chain reaction (RT-PCR). We also investigated the inhibitory mechanism of the mitogen-activated protein kinase (MAPKs) including ERK, JNK, and p38 and nuclear factor-kappaB (NF-𝜅B) by PLP using western blot. Results : PLP did not show cytotoxicity in HaCaT cells. In TNF-𝛼/IFN-𝛾-stimulated HaCaT cells, PLP significantly inhibited the expression of GM-CSF, MCP-1 IL-1𝛽, TNF-𝛼, TARC and IL-6. PLP inhibited the phosphorylation of ERK and translocation of NF-𝜅B into the nucleus. Conclusions : These results indicate that PLP could ameliorate the TNF-𝛼/IFN-𝛾-stimulated inflammatory response through inhibition of MAPK and NF-kB signal pathway. This suggests that PLP could be used beneficial agent to improve skin inflammation.

• Journal of Korean Neurosurgical Society
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• v.65 no.2
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• pp.224-235
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• 2022

Objective : Since the outbreak of the coronavirus disease 2019 (COVID-19) pandemic, neurointerventionists have been increasingly concerned regarding the prevention of infection and time delay in performing emergency thrombectomy procedures in patients with acute stroke. This study aimed to analyze the effects of changes in mechanical thrombectomy protocol before and after the COVID-19 pandemic on procedure time and patient outcomes and to identify factors that significantly impact procedure time. Methods : The last-normal-to-door, first-abnormal-to-door, door-to-imaging, door-to-puncture, and puncture-to-recanalization times of 88 patients (45 treated with conventional pre-COVID-19 protocol and 43 with COVID-19 protection protocol) were retrospectively analyzed. The recanalization time, success rate of mechanical thrombectomy, and modified Rankin score of patients at discharge were assessed. A multivariate analysis was conducted to identify variables that significantly influenced the time delay in the door-to-puncture time and total procedure time. Results : The door-to-imaging time significantly increased under the COVID-19 protection protocol (p=0.0257) compared to that with the conventional pre-COVID-19 protocol. This increase was even more pronounced in patients who were suspected to be COVID-19-positive than in those who were negative. The door-to-puncture time showed no statistical difference between the conventional and COVID-19 protocol groups (p=0.5042). However, in the multivariate analysis, the last-normal-to-door time and door-to-imaging time were shown to affect the door-to-puncture time (p=0.0068 and 0.0097). The total procedure time was affected by the occlusion site, last-normal-to-door time, door-to-imaging time, and type of anesthesia (p=0.0001, 0.0231, 0.0103, and 0.0207, respectively). Conclusion : The COVID-19 protection protocol significantly impacted the door-to-imaging time. Shortening the door-to-imaging time and performing the procedure under local anesthesia, if possible, may be required to reduce the door-to-puncture and door-to-recanalization times. The effect of various aspects of the protection protocol on emergency thrombectomy should be further studied.

• Membrane Journal
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• v.32 no.2
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• pp.140-149
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• 2022

In this study, the conditions of low temperature and high pressure of biogas upgrading process using polysulfone membrane have been designed and tested to achieve the high recovery and efficiency corresponding to those of the highly selective polymeric materials. Polysulfone hollow fiber membrane with 4-component dope solution was spun via non-solvent induced phase separation. The hollow fiber membrane was mounted into a 1.5 inch housing. The effective area was 1.6 m², and its performance was examined in various operation temperatures and pressures. CO₂ and CH₄ permeances were 412 and 12.7 GPU at 20℃, and 280 and 3.6 GPU at -20℃, respectively, while the CO₂/CH₄ selectivity increased from 32.4 to 77.8. Single gas test was followed by the mixed gas experiments using single-stage and double stage where the membrane area ratio varied from 1:1 to 1:3. At the single-stage, CH₄ purity increased and the recovery decreased as the stage-cut increased. At the double stage, the area ratio of 1:3 showed the higher CH₄ recovery as decreasing the operation temperature at the same purity of CH₄ 97%. Finally, polysulfone hollow fiber membranes have yielded of both CH₄ purity and recovery of 97% at -20℃ and 16 barg.

• Journal of Dental Rehabilitation and Applied Science
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• v.38 no.3
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• pp.138-149
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• 2022

The clinical applicability of ceramics can be increased by analyzing the causes of fractures after fracture testing of dental ceramics. Fractography to analyze the cause of fracture of dental ceramics is being widely applied with the development of imaging technologies such as scanning electron microscopy. Setting the experimental conditions is important for accurate interpretation. The fractured specimens should be stored and cleaned to avoid contamination, and metal pretreatment is required for better observation. Depending on the type of fracture, there are dimple rupture, cleavage, and decohesive rupture mainly observed in metals, and fatigue fractures and conchoidal fractures observed in ceramics. In order to reproduce fatigue fracture in the laboratory, which is the main cause of fracture of ceramics, a dynamic loading for observing slow crack growth is essential, and the load conditions and number of loads must be appropriately set. A typical characteristic of a fracture surface of ceramic is a hackle, and the causes of fracture vary depending on the shape of hackle. Fractography is a useful method for in-depth understanding of fractures of dental ceramics, so it is necessary to follow the exact experimental procedure and interpret the results with caution.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.16 no.6
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• pp.213-227
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• 2021

The purpose of this study is to identify factors that are causal and intention to revisit healing agricultural facilities and to identify the relationship between factors. the effect of experience type was analyzed on revisit intention by using facility experience satisfaction as a meditator for healing agriculture participants. The sub-variables of experience types were divided into educational experience, devious experience, entertainment experience, and aesthetic experience. 259 questionnaires collected from the people who experienced healing agriculture programs in the whole country were used for empirical analysis. The PROCESS macro v3.4 and SPSS v22.0 were used to analyze based on the singular simple mediation model which contains a single mediator. First, all types of experience had a positive (+) effect on satisfaction. Second, satisfaction had a positive (+) effect on revisit intention independently of experience type. Third, all types of experience had a positive (+) effect on revisit intention. Fourth, satisfaction mediated between experience type and revisit intention except for deviating experience among experience types. As a follow-up study, it is necessary to study for the adjustment of mediators other than the mediator introduced in the study or the controlled mediated analysis through the conditional process model in which the moderator variable is introduced.

• Journal of Science Education
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• v.46 no.3
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• pp.255-265
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• 2022

The purpose of this study is to analyze and compare brain activation that appears in the self-regulation process of biology major and non-major college students in life science learning. The self-regulation task implemented a life science learning situation with the concept of biological classification. The brain activation of college students was measured and analyzed by fNIRS. In the assimilation process, bilateral FP and left DLPFC show significant activation, and the two groups show a difference in the left OFC activation related to motivation and reward. In the conflict process, the left DLPFC shows significantly lower activation in common, and the two groups show a difference in activation between BA 46, which is related to recent memory, and BA 47, which is related to long-term memory. In the accommodation process, a significantly high activation was found in right DLPFC in common, and the two groups show a difference in activation between right DLPFC and right FP. These areas are in the right frontal lobe area and are related to the understanding of life science knowledge. As a result of this study, it can be seen that the brain activation patterns of biology major and non-major college students are different in the self-regulation process. In addition, we will propose additional neurological studies on self-regulation and present systems and learning strategies that can be constructed in school settings.