• Nutrition Research and Practice
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• v.17 no.5
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• pp.899-916
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• 2023

BACKGROUND/OBJECTIVES: Oxidative stress is a fundamental neurodegenerative disease trigger that damages and decimates nerve cells. Neurodegenerative diseases are chronic central nervous system disorders that progress and result from neuronal degradation and loss. Recent studies have extensively focused on neurodegenerative disease treatment and prevention using dietary compounds. Heseperetin is an aglycone hesperidin form with various physiological activities, such as anti-inflammation, antioxidant, and antitumor. However, few studies have considered hesperetin's neuroprotective effects and mechanisms; thus, our study investigated this in hydrogen peroxide (H₂O₂)-treated SH-SY5Y cells. MATERIALS/METHODS: SH-SY5Y cells were treated with H₂O₂ (400 µM) in hesperetin absence or presence (10-40 µM) for 24 h. Three-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assays detected cell viability, and 4',6-diamidino-2-phenylindole staining allowed us to observe nuclear morphology changes such as chromatin condensation and apoptotic nuclei. Reactive oxygen species (ROS) detection assays measured intracellular ROS production; Griess reaction assays assessed nitric oxide (NO) production. Western blotting and quantitative polymerase chain reactions quantified corresponding mRNA and proteins. RESULTS: Subsequent experiments utilized various non-toxic hesperetin concentrations, establishing that hesperetin notably decreased intracellular ROS and NO production in H₂O₂-treated SH-SY5Y cells (P < 0.05). Furthermore, hesperetin inhibited H₂O₂-induced inflammation-related gene expression, including interluekin-6, tumor necrosis factor-α, and nuclear factor kappa B (NF-κB) p65 activation. In addition, hesperetin inhibited NF-κB translocation into H₂O₂-treated SH-SY5Y cell nuclei and suppressed mitogen-activated protein kinase protein expression, an essential apoptotic cell death regulator. Various apoptosis hallmarks, including shrinkage and nuclear condensation in H₂O₂-treated cells, were suppressed dose-dependently. Additionally, hesperetin treatment down-regulated Bax/Bcl-2 expression ratios and activated AMP-activated protein kinase-mammalian target of rapamycin autophagy pathways. CONCLUSION: These results substantiate that hesperetin activates autophagy and inhibits apoptosis and inflammation. Hesperetin is a potentially potent dietary agent that reduces neurodegenerative disease onset, progression, and prevention.

• Korean Journal of Materials Research
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• v.33 no.10
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• pp.406-413
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• 2023

This study used optical and scanning electron microscopy to analyze the surface oxidation phenomenon that accompanies a γ'-precipitate free zone in a directional solidified CM247LC high temperature creep specimen. Surface oxidation occurs on nickel-based superalloy gas turbine blades due to high temperature during use. Among the superalloy components, Al and Cr are greatly affected by diffusion and movement, and Al is a major component of the surface oxidation products. This out-diffusion of Al was accompanied by γ' (Ni₃Al) deficiency in the matrix, and formed a γ'-precipitate free zone at the boundary of the surface oxide layer. Among the components of CM247LC, Cr and Al related to surface oxidation consist of 8 % and 5.6 %, respectively. When Al, the main component of the γ' precipitation phase, diffused out to the surface, a high content of Cr was observed in these PFZs. This is because the PFZ is made of a high Cr γ phase. Surface oxidation of DS CM247LC was observed in high temperature creep specimens, and γ'-rafting occurred due to stress applied to the creep specimens. However, the stress states applied to the grip and gauge length of the creep specimen were different, and accordingly, different γ'-rafting patterns were observed. Such surface oxidation and PFZ and γ'-rafting are shown to affect CM247LC creep lifetime. Mapping the microstructure and composition of major components such as Al and Cr and their role in surface oxidation, revealed in this study, will be utilized in the development of alloys to improve creep life.

• Nutrition Research and Practice
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• v.17 no.6
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• pp.1084-1098
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• 2023

BACKGROUND/OBJECTIVES: Previous research has shown maternal betaine supplementation alleviates fetal-derived hepatic steatosis. Therefore, this study examined the anti-inflammatory effect of maternal betaine intake in offspring mice and its mechanism. MATERIALS/METHODS: Female C57BL/6J mice and their offspring were randomly divided into 3 groups according to the treatment received during gestation and lactation: control diet (CD), fatty liver disease (FLD), and fatty liver disease + 1% betaine (FLD-BET). The FLD group was given a high-fat diet and streptozotocin (HFD + STZ), and the FLD-BET group was treated with HFD + STZ + 1% betaine. After weaning, the offspring mice were given a normal diet for 5 weeks and then dissected to measure the relevant indexes. RESULTS: Compared to the CD group, the offspring mice in the FLD group revealed obvious hepatic steatosis and increased serum levels of alanine aminotransferase, interleukin (IL)-6, and tumor necrosis factor (TNF)-α; maternal betaine supplementation reversed these changes. The hepatic mRNA expression levels of IL-6, IL-18, and Caspase-1 were significantly higher in the FLD group than in the CD group. Maternal betaine supplementation reduced the expression of IL-1β, IL-6, IL-18, and apoptosis-associated speck-like protein containing C-terminal caspase recruitment domain (ASC). Maternal betaine supplementation also reversed the increasing protein expressions of nitric oxide dioxygenase-like receptor family pyrin domain containing 3 (NLRP3), ASC, Caspase-1, IL-1β, and IL-18 in offspring mice exposed to HFD + STZ. Maternal betaine supplementation decreased the homocysteine (Hcy) and s-adenosine homocysteine (SAH) levels significantly in the livers. Furthermore, the hepatic Hcy concentrations showed significant inverse relationships with the mRNA expression of TNF-α, NLRP3, ASC, and IL-18. The hepatic SAH concentration was inversely associated with the IL-1β mRNA expression. CONCLUSIONS: The lipotropic and anti-inflammatory effect of maternal betaine supplementation may be associated with the inhibition of NLRP3 inflammasome in the livers of the offspring mice.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.34 no.1
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• pp.1-7
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• 2024

β-Ga₂O₃ is a material with a wide band gap of ~4.8 eV and a high breakdown-voltage of 8 MV/cm, and is attracting much attention in the field of power device applications. In addition, compared to representative WBG semiconductor materials such as SiC, GaN and Diamond, it has the advantage of enabling single crystal growth with high growth rate and low manufacturing cost [1-4]. In this study, we succeeded in growing a 10 mm thick β-Ga₂O₃ single crystal doped with 0.3 mol% SnO₂ through the EFG (Edge-defined Film-fed Growth) method using multi-slit structure. The growth direction and growth plane were set to [010]/(010), respectively, and the growth speed was about 12 mm/h. The grown β-Ga₂O₃ single crystal was cut into various crystal planes (010, 001, 100, ${\bar{2}}01$) and surface processed. The processed samples were compared for characteristics according to crystal plane through analysis such as XRD, UV/VIS/NIR/Spec., Mercury Probe, AFM and Etching. This research is expected to contribute to the development of power semiconductor technology in high-voltage and high-temperature applications, and selecting a substrate with better characteristics will play an important role in improving device performance and reliability.

• Resources Recycling
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• v.33 no.1
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• pp.69-76
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• 2024

In an effort to achieve the goal of carbon neutrality, countries around the world are aiming to phase out coal-fired power plants. Due to various reasons, electricity production through coal-fired power generation and sulfur oxide (SOx) emissions are expected to continue in the future. In the South Korea, sodium bicarbonate (NaHCO₃) and lime materials are used to treat SOx, and most of the sodium bicarbonate is imported. Therefore, this research was conducted to replace sodium bicarbonate by improving the physical properties of lime materials using domestic limestone. Limestone was heat-treated through a box-type electric furnace and a vertical electric furnace. Due to the structural characteristics of the vertical electric furnace, a lime material(quicklime) was possible to improve the physical properties like a specific surface area and a pore volume. Then, they were reached to 22.33 m²/g specific area and 0.14 cc/g pore volume.

• Korean Chemical Engineering Research
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• v.62 no.2
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• pp.147-152
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• 2024

Most medical sensors are disposable products. In order to reduce inspection and diagnosis costs, it is more important to develop the inexpensive electrode materials. We fabricated the CuO NPs/PANI/E-PGE as an electrode material for disposable electrochemical sensors and applied it to a non-enzymatic glucose sensor. For surface activation of PGE, pretreatment was performed using chemical and electrochemical methods, respectively. Electrochemical properties according to the pretreatment method were analyzed through chronoamperometry (CA), cyclic voltammetry (CV) and electrochemical impedance (EIS). From these analytical results, the electrochemically pretreated PGE (E-PGE) was finally adopted. The non-enzymatic glucose sensor based on CuO NPs/PANI/E-PGE shows sensitivity of 239.18 mA/mM×cm² (in a linear range of 0.282~2.112 mM) and 36.99 mA/mM×cm² (3.75423~50 mM), detection limit of 17.6 μM and good selectivity. Based on the results of this study, it was confirmed that the modified PGE is a high-performance electrode material. Therefore, these electrodes can be applied to a variety of disposable sensors.

• Journal of the Korean GEO-environmental Society
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• v.25 no.5
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• pp.29-37
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• 2024

This study aimed to investigate the changes in chemical components that occur when weak clay is mixed with steel slag modified with calcium oxide, and to understand the expression characteristics of compressive strength according to hydrophilicity and curing time. XRF testing, SEM imaging, vane shear strength and uniaxial compressive strength testing were conducted. Calcium (Ca) released from the steel slag increases the Ca content in clay by increasing the number of crystal particles and forming a coating layer known as calcium silicate hydrate (CaO-SiO₂-H₂O) through chemical reactions with SiO₂ and Al₂O₃ components. The weak clay stabilized with steel slag is classified into an initial inactive zone where strength relatively does not increase and an activation zone where strength increases over curing time. The vane shear strength of the initial inactive area was found to be 4.4 to 18.4 kN/m² in the state of the weight mixing ratio Rss 30% (steel slag 30% + clay 70%). In the case of the active area, the maximum uniaxial compressive strength increased to 431.8 kN/m² after 480 hours of curing time, which increased due to the apparent adhesion strength of clay through pozzolanic reaction. Therefore, considering the strength expression characteristics of stabilized mixed clay based on the mixing ratio (Rss) during the recycling of steel slag can enhance its practicality in civil engineering sites.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.3
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• pp.127-133
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• 2009

In order to determine organic carbon oxidation by manganese and iron oxides, six core sediments were obtained in slope and basin sediments of Ulleung Basin in East Sea. The basin sediments show high organic carbon contents (>2%) at the water depths deeper than 2,000 m; this is rare for deep-sea sediments, except for those of the Black Sea and Chilean upwelling regions. In the Ullleung Basin, the surface sediments were extremely enriched by Manganese oxides with more than 2%. Maximum contents of Fe oxides were found at the depth of $1{\sim}4cm$ in basin sediments. However, the high level of Mn and Fe oxides was not observed in slope sediment. Surface manganese enrichments (>2%) in Ulleung Basin may be explained by two possible mechanisms: high organic carbon contents and optimum sedimentation rates and sufficient supply of dissolved Manganese from slope to the deep basin. Reduction rates of iron and manganese oxides ranged from 0.10 to $0.24\;mmol\;m^{-2}day^{-1}$ and from 0.30 to $0.57\;mmol\;m^{-2}day^{-1}$, respectively. In Ulleung Basin sediments, $13{\sim}26%$ of organic carbon oxidation may be linked to the reduction of iron and manganese oxides. Reduction rates of metal oxides were comparable to those of Chilean upwelling regions, and lower than those of Danish coastal sediments.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.34 no.2
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• pp.73-77
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• 2024

The spinel-type oxide (Ni_x, Mn_y, Co_3-x-y)O₄ (NMC) is widely utilized as a material for temperature sensors with a negative temperature coefficient (NTC), finding applications across various industries including electric vehicle battery management systems. Typically, NMC is manufactured using solid-state reaction methods employing powders of Ni, Mn, and Co compounds, with the densification process through sintering recognized as a crucial factor determining the electrical properties of the temperature sensor material. In this study, NMC pellets were synthesized via solid-state reaction and their crystallographic and microstructural characteristics were investigated. Also, the activation energy for densification behavior during the sintering process was determined. According to the analysis results, the room temperature resistance of the NMC pellets was measured at 10.03 Kohm, with the sensitivity parameter, B-value, recorded at 3601.8 K, indicating their potential applicability as temperature sensors across various industrial fields. Furthermore, the activation energy for densification was found to be 273.3 ± 0.4 kJ/mol, providing valuable insights into the thermodynamic aspects of the sintering process of the NMC.

• Korean Journal of Organic Agriculture
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• v.32 no.1
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• pp.91-105
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• 2024

Plantago asiatica L. (P. asiatica) is a perennial plant belonging to the plantaginaceae and is useful in treating a various diseases such as wounds, bronchitis, and chronic constipation. The bioactive effects of P. asiatica extract was evaluated to determine its potential for use as a variety materials in the food, pharmaceutical, and agricultural industries. Polyphenol and flavonoid contents, free radical scavenging, reducing power activity, and reactive oxygen species (ROS) expression were measured to identify the antioxidative activity. Anti-inflammatory effects were evaluated via analysis of nitric oxide (NO) and pro-inflammatory protein expression in LPS-induced RAW 264.7 cell. As a result of measuring the antioxidant activities of the P. asiatica extract, the total polyphenol content was 50.91±0.78 mg gallic acid equivalents/g and the flavonoid content was 100.99±0.44 mg rutin equivalents/g, and both DPPH and ABTS radical scavenging activities and reducing power increased depending on the concentration. Also, intracellular ROS production was inhibited by the P. asiatica extract. No cytotoxicity was observed when P. asiatica extract was treated, and NO and inflammatory protein expression were inhibited, and nuclear factor kappa B (NF-κB) phosphorylation was also inhibited in a concentration-dependent manner. In conclusion, P. asiatica is a functional natural resources of antioxidant and anti-inflammatory agents that can be used in various industries, including food and agriculture.