• 한국재료학회지
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• 제31권11호
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• pp.642-648
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• 2021

The precipitation effect of Al-6%Si-0.4%Mg-0.9%Cu-(Ti) alloy (in wt.%) after various heat treatments was studied using a laser flash device (LFA) and differential scanning calorimetry (DSC). Solid solution treatment was performed at 535 ℃ for 6 h, followed by water cooling, and samples were artificially aged in air at 180 ℃ and 220 ℃ for 5 h. The titanium-free alloy Al-6%Si-0.4%Mg-0.9%Cu showed higher thermal diffusivity than did the Al-6%Si-0.4%Mg-0.9%Cu-0.2%Ti alloy over the entire temperature range. In the temperature ranges below 200 ℃ and above 300 ℃, the value of thermal diffusivity decreased with increasing temperature. As the sample temperature increased between 200 ℃ and 400 ℃, phase precipitation occurred. From the results of DSC analysis, the temperature dependence of the change in thermal diffusivity in the temperature range between 200 ℃ and 400 ℃ was strongly influenced by the precipitation of θ'-Al₂Cu, β'-Mg₂Si, and Si phases. The most important factor in the temperature dependence of thermal diffusivity was Si precipitation.

• BMB Reports
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• 제55권2호
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• pp.104-109
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• 2022

Skeletal myogenesis is essential to keep muscle mass and integrity, and impaired myogenesis is closely related to the etiology of muscle wasting. Recently, miR-141-3p has been shown to be induced under various conditions associated with muscle wasting, such as aging, oxidative stress, and mitochondrial dysfunction. However, the functional significance and mechanism of miR-141-3p in myogenic differentiation have not been explored to date. In this study, we investigated the roles of miR-141-3p on CFL2 expression, proliferation, and myogenic differentiation in C2C12 myoblasts. MiR-141-3p appeared to target the 3'UTR of CFL2 directly and suppressed the expression of CFL2, an essential factor for actin filament (F-actin) dynamics. Transfection of miR-141-3p mimic in myoblasts increased F-actin formation and augmented nuclear Yes-associated protein (YAP), a key component of mechanotransduction. Furthermore, miR-141-3p mimic increased myoblast proliferation and promoted cell cycle progression throughout the S and G2/M phases. Consequently, miR-141-3p mimic led to significant suppressions of myogenic factors expression, such as MyoD, MyoG, and MyHC, and hindered the myogenic differentiation of myoblasts. Thus, this study reveals the crucial role of miR-141-3p in myogenic differentiation via CFL2-YAP-mediated mechanotransduction and provides implications of miRNA-mediated myogenic regulation in skeletal muscle homeostasis.

• International journal of advanced smart convergence
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• 제11권3호
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• pp.197-205
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• 2022

In order to investigate the effect of an 8-week elastic band exercise program according to age on the isokinetic strength and dynamic equilibrium of the knee, 10 women under 49 years old and 10 women over 50 years old were selected. Dynamic equilibrium was measured through Y-Balance test one week before the exercise program, and power and endurance were confirmed by measuring isokinetic muscle strength of the knee. After measurement, small tool exercise was performed for 8 weeks. After 8 weeks of exercise, isokinetic muscle strength and dynamic equilibrium were measured. As a result, isokinetic muscle strength, which checks muscle strength and muscular endurance, increased after measurement than before measurement regardless of age, and dynamic equilibrium increased after measurement rather than before measurement, and the group under 49 years of age was higher than the group over 50 years old. We think that small tool exercise improves isokinetic muscle strength and is effective in neuromuscular development, improving dynamic stability ability, which is an important factor in preventing falls.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제29권1호
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• pp.29-42
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• 2023

Purpose: This study aimed to develop a daylighting design indicator for Korean dementia nursing homes based on the therapeutic effects of light, focusing on the serious aging index facing Korea and the importance of natural light that occupies the most important position in the therapeutic environments for the elderly with dementia. Methods: A wide range of literature-oriented research methods were mobilized to develop the daylighting design indicator of Korean dementia nursing homes. Results: The daylighting design indicator of Korean dementia nursing homes was derived from three perspectives: maximizing daylight availability, optimizing therapeutic view, and minimizing glare. In addition, eighteen basic indicators were derived within seven indicator items in the range of building layout, windows, glazing, shading devices, spaces, interior finishings, and daylight factor. Implications: The daylighting design indicator of Korean dementia nursing homes revealed in this study will contribute to realizing Korean dementia nursing homes as a therapeutic environment for the elderly with dementia.

• The Korean Journal of Physiology and Pharmacology
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• 제27권1호
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• pp.105-112
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• 2023

Oxidative stress in skin cells can induce the formation of reactive oxygen species (ROS), which are critical for pathogenic processes such as immunosuppression, inflammation, and skin aging. In this study, we confirmed improvements from gamma-irradiated silk sericin (I-sericin) and gamma-irradiated silk fibroin (I-fibroin) to skin cells damaged by oxidative stress. We found that I-sericin and I-fibroin effectively attenuated oxidative stress-induced ROS generation and decreased oxidative stress-induced inflammatory factors COX-2, iNOS, tumor necrosis factor-α, and interleukin-1β compared to the use of non-irradiated sericin or fibroin. I-sericin and Ifibroin effects were balanced by competition with skin regenerative protein factors reacting to oxidative stress. Taken together, our results indicated that, compared to non-irradiated sericin or fibroin, I-sericin, and I-fibroin had anti-oxidation and antiinflammation activity and protective effects against skin cell damage from oxidative stress. Therefore, gamma-irradiation may be useful in the development of cosmetics to maintain skin health.

• Journal of Applied Biological Chemistry
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• 제65권4호
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• pp.277-286
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• 2022

Schizophragma hydrangeoides (S. hydrangeoides) is a vine endogenous to Jeju Island and Ulleungdo, where it grows attached to the foothills and rock surfaces. Previous research has mostly focused on the whitening effect of S. hydrangeoides leaf extract. In this study, we investigated S. hydrangeoides leaf extract further, and detected four phytochemicals in the extract: chlorogenic acid, quercetin-3-O-glucosyl-(1-2)-rhamnoside, quercetin-3-O-xylosyl-(1-2)-rhamnoside, and quercitrin. We pretreated human dermal fibroblast (HDFn) cells with previously established concentrations of the four compounds for 1 h before ultraviolet A (UVA) irradiation. Among the four compounds, quercetin-3-O-glucosyl-(1-2)-rhamnoside (Q-3-GR) best inhibited matrix metalloproteinase-1 (MMP-1) levels. Thus, we investigated the protective effects of Q-3-GR on photoaging and its underlying mechanisms. Q-3-GR significantly reduced MMP-1 production and inhibited MMP-1 protein expression in UVA-irradiated HDFn cells. Furthermore, Q-3-GR increased procollagen type I production and protein expression. Q-3-GR exerted its anti-photoaging effects by downregulating the mitogen-activated protein kinase/ activator protein-1 signaling pathway, and upregulating the transforming growth factor-β/Smad signaling pathway. Thus, S. hydrangeoides leaf-derived Q-3-GR is a potential potent cosmetic ingredient for UV-induced skin aging.

• Journal of the Korean Wood Science and Technology
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• 제51권3호
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• pp.173-182
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• 2023

Color is an attribute of visual perception and can be an important factor that affects the preference of customers toward bamboo and wood products. Solar radiation can discolor bamboo surfaces and initiate cracking. The purpose of this study is to investigate the effects of an ultraviolet (UV)-protective coating on the photodiscoloration of untreated and heat-treated Phyllostachys bambusoides bamboo surfaces. Artificial UVA radiators are set at a UVA irradiance of 2,000 W/m² to accelerate the aging of the outer surfaces of hot-air-dried and heat-treated bamboo samples. Half of the samples are coated with transparent UV-protective paint. As the UVA radiation progresses, the discoloration prevention efficiency (DPE) of the UV-protective coating on all samples decreases gradually. The DPEs of the hot-air-dried samples are estimated to be 31.4% and 18.8% after 21 and 72 hours of artificial UVA radiation, respectively. The heat-treated samples exhibit similar trends (29.0% after 21 hours and 10.3% after 72 hours). Recoating the UV-protective paint periodically every six months is expected to minimize the discoloration of the bamboo's outer surface.

• 농촌계획
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• 제28권1호
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• pp.49-55
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• 2022

School closures in rural areas is especially relevant because low fertility rate and population aging are common not only in rural but also in urban areas. This paper examined a variety of users' perceptions on welfare facilities using closed rural schools. For this study, the descriptive survey research design was conducted at the EZER located in Kyungsnangbuk-do. The sample size of 200 was selected through convenience sampling and data collection was completed by a self-completion written questionnaires. Main findings are as follows: 1) the level of users' relative satisfaction with welfare facilities using closed rural schools was generally positive, main factor associated with relative satisfaction was facilities and surrounding environment at closed rural schools, 2) socioeconomic usefulness of closed rural schools was also was generally positive, main factors for revitalization were adequate facilities and places, accessible and convenient places, 3) future necessity and willingness for welfare facilities using closed rural schools were overwhelmingly positive, children or youth were revealed as a priority service target. Finally, theses analyses show that a high proportion in the rural welfare sector, especially seemed to have a positive impact on bridging negative gabs between urban and rural in the socioeconomic development and social welfare.

• Nutrition Research and Practice
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• 제17권4호
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• pp.641-659
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• 2023

BACKGROUND/OBJECTIVES: The skin is the outermost organ of the human body and plays a protective role against external environmental damages, such as sunlight and pollution, which affect anti-oxidant defenses and skin inflammation, resulting in erythema or skin reddening, immunosuppression, and epidermal DNA damage. MATERIALS/METHODS: The present study aimed to investigate the potential protective effects of red orange complex H extract (ROC) against ultraviolet (UV)-induced skin photoaging in Skh:HR-2 mice. ROC was orally administered at doses of 20, 40, and 80 mg/kg/day for 13 weeks, along with UV irradiation of the mice for 10 weeks. RESULTS: ROC improved UV-induced skin barrier parameters, including erythema, melanin production, transepidermal water loss, elasticity, and wrinkle formation. Notably, ROC inhibited the mRNA expression of pro-inflammatory cytokines (interleukin 6 and tumor necrosis factor α) and melanogenesis. In addition, ROC recovered the UV-induced decrease in the hyaluronic acid and collagen levels by enhancing genes expression. Furthermore, ROC significantly downregulated the protein and mRNA expression of matrix metalloproteinases responsible for collagen degradation. These protective effects of ROC against photoaging are associated with the suppression of UV-induced phosphorylation of c-Jun NH2-terminal kinase and activator protein 1 activation. CONCLUSIONS: Altogether, our findings suggest that the oral administration of ROC exerts potential protective activities against photoaging in UV-irradiated hairless mice.

• Nutrition Research and Practice
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• 제17권5호
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• pp.870-882
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• 2023

BACKGROUND/OBJECTIVES: Obesity is a major risk factor for metabolic syndrome, a global public health problem. Mentha canadensis (MA), a traditional phytomedicine and dietary herb used for centuries, was the focus of this study to investigate its effects on obesity. MATERIALS/METHODS: Thirty-five male C57BL/6J mice were randomly divided into 2 groups and fed either a normal diet (ND, n = 10) or a high-fat diet (HFD, n = 25) for 4 weeks to induce obesity. After the obesity induction period, the HFD-fed mice were randomly separated into 2 groups: one group continued to be fed HFD (n = 15, HFD group), while the other group was fed HFD with 1.5% (w/w) MA ethanol extract (n = 10, MA group) for 13 weeks. RESULTS: The results showed that body and white adipose tissue (WAT) weights were significantly decreased in the MA-supplemented group compared to the HFD group. Additionally, MA supplementation enhanced energy expenditure, leading to improvements in plasma lipids, cytokines, hepatic steatosis, and fecal lipids. Furthermore, MA supplementation regulated lipid-metabolism-related enzyme activity and gene expression, thereby suppressing lipid accumulation in the WAT and liver. CONCLUSIONS: These findings indicate that MA has the potential to improve diet-induced obesity and its associated complications, including adiposity, dyslipidemia, hepatic steatosis, and inflammation.