• Composites Research
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• v.34 no.5
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• pp.290-295
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• 2021

The application of lightweight structural composites to automobiles as a solution in line with global fuel economy regulations to curb global warming is recognized as a megatrend. This study was conducted to provide a technical approach that can respond to the issue of replacing parts that require conductive properties to maximize the application of thermoplastic carbon fiber reinforced plastics (CFRPs), which are advantageous in terms of repair, disposal and recycling. By utilizing the properties of the low-viscosity polymerizable oligomer matrix, it was possible to prepare a thermoplastic CFRP exhibiting excellent impregnation properties while uniformly mixing the conductive filler. Various carbon-based conductive fillers such as carbon black, carbon nanotubes, graphene nanoplatelets, graphite, and pitch-based carbon fibers were filled up to the maximum content, and electrical and thermal conductive properties of the fabricated composites were compared and studied. It was confirmed that the maximum incorporation of filler was the most important factor to control the conductive properties of the composites rather than the type or shape of the conductive carbon filler. Experimental results were observed in which it might be advantageous to apply a one-dimensional conductive carbon filler to improve electrical conductivity, whereas it might be advantageous to apply a two-dimensional conductive carbon filler to improve thermal conductivity. The results of this study can provide potential insight into the optimization of structural design for controlling the conductive properties of thermoplastic CFRPs.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.3
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• pp.268-275
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• 2021

The three factors that determine the strength of concrete are the strength of cement paste, aggregate and ITZ(Interfacial Transition Zone) between aggregate and cement paste. Out of these, the strength of ITZ is the most vulnerable. ITZ is formed in 10~50㎛, the ratio of calcium hydroxide is high, and CSH appears low ratio. A high calcium hydroxide ratio causes a decrease in the bond strength of ITZ. ITZ is due to further weak area. The problem of ITZ appears as a more disadvantageous factor when it used lightweight aggregate. The previous study of ITZ properties have measured interfacial toughness, identified influencing factors ITZ, and it progressed SEM and XRD analysis on cement matrix without using coarse aggregates. also it was identified microstructure using EMPA-BSE equipment. However, in previous studies, it is difficult to understand the microstructure and mechanical properties. Therefore, in this study, a method of measuring electrical resistance using EIS(Electrochemical Impedance Spectroscopy) measuring equipment was adopted to identify the ITZ between natural aggregate and lightweight aggregate, and it was tested the change of ITZ by surface coating of lightweight aggregate with ground granulated blast furnace slag. As a result, the compressive strength of natural aggregate and lightweight aggregate appear high strength of natural aggregate with high density, surface coating lightweight aggregate appear strength higher than natural aggregate. The electrical resistivity of ITZ according to the aggregate appeared difference.

• Animal Bioscience
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• v.34 no.6
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• pp.957-966
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• 2021

Objective: Ovarian follicular development, which dependent on the proliferation and differentiation of granulosa cells (GCs), is a complex biological process in which miRNA plays an important role. Our previous study showed that miR-458b-5p is associated with ovarian follicular development in chicken. The detailed function and molecular mechanism of miR-458b-5p in GCs is unclear. Methods: The luciferase reporter assay was used to verify the targeting relationship between miR-458b-5p and catenin beta-1 (CTNNB1), which is an important transcriptional regulatory factor of the Wnt/β-catenin pathway. The cell counting kit-8 (CCK-8) assay, flow cytometry with propidium iodide (PI) and annexin V-fluorescein isothiocyanate (FITC) labeling were applied to explore the effect of miR-458b-5p on proliferation, cell cycle and apoptosis of chicken GCs. Quantitative real-time polymerase chain reaction and Western blot were used to detect the mRNA and protein expression levels. Results: We demonstrated that the expression of miR-458b-5p and CTNNB1 showed the opposite relationship in GCs and theca cells of hierarchical follicles. The luciferase reporter assay confirmed that CTNNB1 is the direct target of miR-458b-5p. Using CCK-8 assay and flow cytometry with PI and Annexin V-FITC labeling, we observed that transfection with the miR-458b-5p mimics significantly reduced proliferation and has no effects on apoptosis of chicken GCs. In addition, miR-458b-5p decreased the mRNA and protein expression of CD44 molecule and matrix metallopeptidase 7, which are the downstream effectors of CTNNB1 in Wnt/β-Catenin pathway and play functional roles in cell proliferation. Conclusion: Taken together, the data indicate that miR-458b-5p regulates ovarian GCs proliferation through Wnt/β-catenin signaling pathway by targeting CTNNB1, suggesting that miR-458b-5p and its target gene CTNNB1 may potentially play a role in chicken ovarian follicular development.

• The Korean Journal of Oral and Maxillofacial Pathology
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• v.42 no.5
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• pp.111-118
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• 2018

Nicotine of tobacco component has a controversial impact in the clinical outcome of dental implants. Although numerous nicotine effects on bone healing around implants have been presented, it is rarely reported in vitro study about normal human osteoblast(NHost) from oral and maxillofacial area at the surface of implants. The purpose of the present study was to evaluate the effect of nicotine on the proliferation and differentiation response of NHost to plasmatic and salivary levels of nicotine reported in smokers at the surface of screw-type plasma-sprayed titanium implants. NHosts were seeded on the surface of titanium implants and cultured for 21 days in ${\alpha}-MEM$ supplemented with 10% FBS, 50mg/ml ascorbic acid, 5mM ${\beta}$-glycerophosphate and 100nM dexamethasone. Seeded implants were exposed to various nicotine concentration(0.05-0.5mg/ml) from 1 to 21 days, and characterized for cell morphology, proliferation, differentiation, alkaline phosphatase(ALP) activity and ionized calcium concentration(Cai) of medium. Continuous exposure to higher nicotine concentration(above 0.3mg/ml) induced a dose- and time-dependent vacuolation of the cytoplasm, and a tendency to detach from the implant surface. 0.05mg/ml(lower nicotine concentration) did not cause significant effects in the cell proliferation and ALP activity. 0.1-0.2mg/ml caused evident dose-dependent effects in increased cell proliferation, ALP activity and earlier onset of matrix mineralization at levels up to 0.2mg/ml, while a dose-dependent inhibitory effect at 0.3-0.5mg/ml. Cai concentration of control group was decreased at 14 days. Increased Cai concentration at 0.1-0.2mg/ml, decreased Cai concentration at 0.3mg/ml and no change at 0.5mg/ml during the culture period were seen. It suggested that nicotine concentration could paly an role in modulating NHost activity as a contributing factor associated with proliferation and differentiation of NHost at the surface of implants.

• Clinical and Experimental Reproductive Medicine
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• v.48 no.2
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• pp.111-123
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• 2021

Objective: Using domestic cats as a biomedical research model for fertility preservation, the present study aimed to characterize the influences of ovarian tissue encapsulation in biodegradable hydrogel matrix (fibrinogen/thrombin) on resilience to cryopreservation, and static versus non-static culture systems following ovarian tissue encapsulation and cryopreservation on follicle quality. Methods: In experiment I, ovarian tissues (n=21 animals; 567 ovarian fragments) were assigned to controls or hydrogel encapsulation with 5 or 10 mg/mL fibrinogen (5 or 10 FG). Following cryopreservation (slow freezing or vitrification), follicle viability, morphology, density, and key protein phosphorylation were assessed. In experiment II (based on the findings from experiment I), ovarian tissues (n=10 animals; 270 ovarian fragments) were encapsulated with 10 FG, cryopreserved, and in vitro cultured under static or non-static systems for 7 days followed by similar follicle quality assessments. Results: In experiment I, the combination of 10 FG encapsulation/slow freezing led to greater post-thawed follicle quality than in the control group, as shown by follicle viability (66.9%±2.2% vs. 61.5%±3.1%), normal follicle morphology (62.2% ±2.1% vs. 55.2%±3.5%), and the relative band intensity of vascular endothelial growth factor protein phosphorylation (0.58±0.06 vs. 0.42±0.09). Experiment II demonstrated that hydrogel encapsulation promoted follicle survival and maintenance of follicle development regardless of the culture system when compared to fresh controls. Conclusion: These results provide a better understanding of the role of hydrogel encapsulation and culture systems in ovarian tissue cryopreservation and follicle quality outcomes using an animal model, paving the way for optimized approaches to human fertility preservation.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.4
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• pp.498-505
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• 2020

Aggregate occupies about 70-85% of the concrete volume and is an important factor in reducing the drying shrinkage of concrete. However, when constructing high-rise buildings, it acts as a problem due to the high load of natural aggregates. If the load becomes large during the construction of a high-rise building, creep may occur and the ground may be eroded. Material costs increase and there are financial problems. In order to reduce the load on concrete, we are working to reduce the weight of aggregates. However, artificial lightweight aggregates affect the interface between the aggregate and the paste due to its higher absorption rate and lower adhesion strength than natural aggregates, affecting the overall strength of concrete. Therefore, in this study, in order to grasp the interface between natural aggregate and lightweight aggregate by type, we adopted a method of measuring electrical resistance using an EIS measuring device, which is a non-destructive test, and lightweight bone. The change in the state of the interface was tested on the outside of the material through a blast furnace slag coating. As a result of the experiment, it was confirmed that the electric resistance was about 90% lower than that in the air-dried state through the electrolyte immersion, and the electric resistance differs depending on the type of aggregate and the presence or absence of coating. As a result of the experiment, the difference in compressive strength depending on the type of aggregate and the presence or absence of coating was shown, and the difference in impedance value and phase angle for each type of lightweight aggregate was shown.

• The Korea Journal of Herbology
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• v.32 no.5
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• pp.1-6
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• 2017

Objectives : Corni Fructus (CF) is traditional herbal medicine used on polyuria, low back pain, and tinnitus. This study aimed to evaluate inhibits skin wrinkle formation effect of CF. Methods : To evaluate the produce inhibition effect of CF, SD-rats were distributed into four groups; normal rats (Nor), AGEs (advenced glycation end product)-induced rats (Con), AGEs-induced rats treated with 100mg/kg CF (CF). To induce AGEs, streptozotocin (50mg/kg) was administered intraperitoneally and after 3 days oral administrated 100mM methyl glyoxal for 3 weeks. Results : The oral administration of CF suppressed the reactive oxygen specis (ROS) in serum. The AGEs in skin tissues was significantly reduced through treatment of CF. Furthermore, the expressions of AGEs related proteins such as polyclonal anti-$N^e$-(carboxymethyl)lysine (CML), anti-$N^e$-(carboxyethyl)lysine (CEL), AGE receptors (RAGE) were decreased in CF treated group compared with the control group in skin tissues. Inflammation-related proteins such as Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB), monocyte chemoattractant protein-1 (MCP-1), interleukin-6 (IL-6) reduced in CF treatment group than control group. AGE-induced rats exhibited that the significant decreased collagen however, CF treatment (100mg/kg of body weight) up regulated collagen by improved the expression levels of skin fibril-related genes such as Matrix metalloproteinase (MMP-1). Conclusion : Taken together, our study suggests that CF regulates ROS to prevent accumulation of AGEs and inhibits skin wrinkles. Our finding indicate that CF may be an effective agent for inhibits AGEs formation, and improved skin wrinkle.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.35 no.4
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• pp.63-74
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• 2022

Objectives : Skin aging is generally characterized by wrinkles, sagging, loss of elasticity roughness, pigmentation and dryness. This changes is caused by reducing the elements constituting the extracellular matrix contributing to the physiological properties of the skin, such as collagen fiber, elastic fiber, and hyaluronic acid. Adequate skin hydration is important to maintain normal skin function and reduce skin aging. The present study is objective to observe skin moisturizing effects of Unripe apple(UA, Immature fruit of Malus pumila Mill) in vivo and its underlying molecular mechanisms. Methods : ICR mice were orally administerd UA(100, 200 and 400mg/kg/day) for 8 weeks, and skin water contents and the expression of transforming growth factor (TGF)-𝛽1, ceramide, hyaluronan and collagen type I(COL1) were measured in dorsal back skin of the mice. Gene expression of hyaluronan synthase(HAS1, HAS2, HAS3), collagen synthase(COL1A1, COL1A2) and TGF-𝛽1 were also determined by realtime RT-PCR. Results : Skin water contents and the expression of TGF-𝛽1, ceramide, COL1 and hyaluronan were significantly increased in UA group(100, 200 and 400mg/kg/day) compared to vehicle control. The mRNA expression of HAS isoform(HAS1, HAS2, HAS3), COL1A1, COL1A2, and TGF-𝛽1 were also significantly increased by UA. Conclusions : UA has skin moisturizing effects and enhancement activities in skin function related components(COL1, hyaluronan, ceramide and TGF-𝛽1). These results suggested that UA can be a developing candidate for developing alternative skin protective agent or functional food ingredient.

• Journal of the Korean Geotechnical Society
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• v.26 no.3
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• pp.59-68
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• 2010

Systematic risk management is necessary in grand scaled urban construction because of the existence of complicated and various risk factors. Problems of obstructions, adjacent structures, safety, environment, traffic and geotechnical properties need to be solved because urban construction is progressed in limited space not as general earthwork. Therefore the establishment of special risk management system is necessary to manage not only geotechnical properties but also social and cultural uncertainties. This research presents the technique analysis by the current state of risk management technique. Risk factors were noticed and the importance of each factor was estimated through survey. The systemically categorized database was established. Risk extraction module, matrix and score module were developed based on the database. Expected construction budget and time distribution can be computed by Monte Carlo analysis of probabilities and influences. Construction budgets and time distributions of before and after response can be compared and analyzed 80 the risks are manageable for entire whole construction time. This system will be the foundation of standardization and integration. Procurement, efficiency improvement, effective time and resource management are available through integrated management technique development and application. Conclusively decrease in cost and time is expected by systemization of project management.

• Journal of Ginseng Research
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• v.47 no.4
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• pp.515-523
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• 2023

Background: 20(S)-protopanaxadiol (PPD), one of the main components of ginseng, has anti-inflammatory, anti-estrogenic, and anti-tumor activities. It is known that activated hepatic stellate cells (HSCs) are the primary producers of extracellular matrix (ECM) in the liver, and the Wnt/β-catenin pathway participates in the activation of HSCs. We aimed to explore whether PPD inhibits liver fibrosis is associated with the Wnt/β-catenin pathway inactivation. Methods: The anti-fibrotic roles of PPD were examined both in vitro and in vivo. We also examined the levels of Wnt inhibitory factor 1 (WIF1), DNA methyltransferase 1 (DNMT1) and WIF1 methylation. Results: PPD obviously ameliorated liver fibrosis in carbon tetrachloride (CCl₄)-treated mice and reduced collagen deposition. PPD also suppressed the activation and proliferation of primary HSCs. Notably, PPD inhibited the Wnt/β-catenin pathway, reduced TCF activity, and increased P-β-catenin and GSK-3β levels. Interestingly, WIF1 was found to mediate the inactivation of the Wnt/β-catenin pathway in PPD-treated HSCs. WIF1 silencing suppressed the inhibitory effects of PPD on HSC activation and also restored α-SMA and type I collagen levels. The downregulation of WIF1 expression was associated with the methylation of its promoter. PPD induced WIF1 demethylation and restored WIF1 expression. Further experiments confirmed that DNMT1 overexpression blocked the effects of PPD on WIF1 expression and demethylation and enhanced HSC activation. Conclusion: PPD up-regulates WIF1 levels and impairs Wnt/β-catenin pathway activation via the downregulation of DNMT1-mediated WIF1 methylation, leading to HSC inactivation. Therefore, PPD may be a promising therapeutic drug for patients with liver fibrosis.