• Journal of the Korean Institute of Gas
• /
• v.26 no.2
• /
• pp.49-55
• /
• 2022

According to reinforce environmental regulations, coal power plants have used selective catalytic reduction using ammonia as a reducing agent to reduce the amount of nitrogen oxide generation. The purpose of the present study was to derive a mixing device for effectively mixing dilute air and ammonia in the ammonia mixing pipe by performing computational fluid dynamic analysis. The mixing effect was compared by analysing the %RMS of ammonia concentration at the down stream cross section in the mixing pipe and the 16 outlets based on the case 1-1 shape, which is an existing mixing pipe without a mixing device. The mixing device was performed by changing the positions of a square plate on the downstream side of the ammonia supply pipe and an arc-shaped plate on the wall of the mixing pipe. In the case of the existing geometry(Case 1-1), the %RMS of ammonia concentration at the 16 outlets was 29.50%. The shape of the mixing device for Case 3-2 had a square plate on the downstream side of the ammonia supply pipe and an arc plate was installed adjacent to it. The %RMS of ammonia concentration for Case 3-2 was 2.08% at 16 outlets and it could be seen that the shape of Case 3-2 was the most effective mixing shape for ammonia mixing.

• Journal of Powder Materials
• /
• v.29 no.5
• /
• pp.411-417
• /
• 2022

Environmental issues such as global warming due to fossil fuel use are now major worldwide concerns, and interest in renewable and clean energy is growing. Of the various types of renewable energy, green hydrogen energy has recently attracted attention because of its eco-friendly and high-energy density. Electrochemical water splitting is considered a pollution-free means of producing clean hydrogen and oxygen and in large quantities. The development of non-noble electrocatalysts with low cost and high performance in water splitting has also attracted considerable attention. In this study, we successfully synthesized a NiCo₂O₄/NF electrode for an oxygen evolution reaction in alkaline water splitting using a hydrothermal method, which was followed by post-heat treatment. The effects of heat treatment on the electrochemical performance of the electrodes were evaluated under different heat-treatment conditions. The optimized NCO/NF-300 electrode showed an overpotential of 416 mV at a high current density of 50 mA/cm² and a low Tafel slope (49.06 mV dec^-1). It also showed excellent stability (due to the large surface area) and the lowest charge transfer resistance (12.59 Ω). The results suggested that our noble-metal free electrodes have great potential for use in developing alkaline electrolysis systems.

• Journal of Food Hygiene and Safety
• /
• v.37 no.4
• /
• pp.207-215
• /
• 2022

The intensity of fishy odor in eggs, which differs depending on the poultry type and individual perception, can be due to many factors including trimethylamine (TMA) which has been identified as the main. Notably, riboflavin can increase the activity of flavin-containing monooxygenase 3, the enzyme responsible for converting TMA into odorless trimethylamine-N-oxide. This study aimed to analyze the TMA content in egg yolk, evaluate its contribution to fishy odor, and develop a method to prevent this undesired odor. Solid-phase microextraction-gas chromatography/mass spectrometry was used to detect and quantify volatile compounds in egg yolk from hens fed a standard TMA-rich diet and hens fed a riboflavin-supplemented diet. To compare the relative content of volatile substances between eggs, a correlation study was performed using an electronic nose. Higher concentration of TMA (1.06 ± 0.12 mg/kg) was detected in egg yolks obtained from hens fed a normal diet than those fed a riboflavin-supplemented diet. Overall, this study suggests that riboflavin affects the quantity and quality of volatile substances, including TMA, present in eggs and we expect these findings to improve the quality and reduce the fishy odor of eggs.

• Nutrition Research and Practice
• /
• v.16 no.5
• /
• pp.549-564
• /
• 2022

BACKGROUND/OBJECTIVES: Oxidative stress is caused by an imbalance between harmful free radicals and antioxidants. Long-term oxidative stress can lead to an "exhausted" status of antioxidant defense system triggering development of metabolic syndrome and chronic inflammation. Green perilla (Perilla frutescens) is commonly used in Asian cuisines and traditional medicine in southeast Asia. Green perilla possesses numerous beneficial effects including anti-inflammatory and antioxidant functions. To investigate the potentials of green perilla leaf extract (PE) on oxidative stress, we induced oxidative stress by high-fat diet (HFD) in aging mice. MATERIALS/METHODS: C57BL/6J male mice were fed HFD continuously for 53 weeks. Then, mice were divided into three groups for 12 weeks: a normal diet fed reference group (NDcon), high-fat diet fed group (HDcon), and high-fat diet PE treated group (HDPE, 400 mg/kg of body weight). Biochemical analyses of serum and liver tissues were performed to assess metabolic and inflammatory damage and oxidative status. Hepatic gene expression of oxidative stress and inflammation related enzymes were evaluated by quantitative real-time polymerase chain reaction (qRT-PCR). RESULTS: PE improved hepatopathology. PE also improved the lipid profiles and antioxidant enzymes, including hepatic glutathione peroxidase (GPx) and superoxide dismutase (SOD) and catalase (CAT) in serum and liver. Hepatic gene expressions of antioxidant and anti-inflammatory related enzymes, such as SOD-1, CAT, interleukin 4 (IL-4) and nuclear factor erythroid 2-related factor (Nrf2) were significantly enhanced by PE. PE also reduced the levels of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) in the serum and liver; moreover, PE suppressed hepatic gene expression involved in pro-inflammatory response; Cyclooxygenase-2 (COX-2), nitric oxide synthase (NOS), interleukin 1 beta (IL-1β), and interleukin 6 (IL-6). CONCLUSIONS: This research opens opportunities for further investigations of PE as a functional food and possible anti-aging agent due to its attenuative effects against oxidative stress, resulting from HFD and aging in the future.

• Journal of Korean Medicine Rehabilitation
• /
• v.32 no.4
• /
• pp.9-18
• /
• 2022

Objectives This study was conducted to confirm the anti-inflammatory effect of Naetakbaekryeom-san (NTB), and whether it could be another treatment for inflammatory diseases. Methods The NTB water extract was extracted with hot water at 100℃ for 2 hours, concentrated at 80℃ under reduced pressure, and used. After 2 hours of pretreatment with NTB and positive control Bay11-7082, nitric oxide (NO), inducible NO synthase (iNOS), interleukin (IL)-6, IL-1𝛽, tumor necrosis factor alpha (TNF-𝛼) were measured in RAW264.7 cells activated with lipopolysaccharides (LPS) 500 ng/mL. After 2 hours of pretreatment with NTB, the anti-inflammatory effect of NTB was evaluated by measuring nuclear factor kappa-light-chain-enhancer of activated B cells (NF-𝜅B) in RAW264.7 cells and 293T cells activated with phorbol 12-myristate 13-acetic acid (PMA) 30 ng/mL. Results In RAW264.7 cells activated with LPS, NTB at concentrations of 0.1, 0.3, and 1.0 mg/mL showed no cytotoxicity, significantly inhibited NO production and inhibition of iNOS expression. TNF-𝛼 cytokine levels was not regulated, but NTB at each concentration inhibited the production of IL-1𝛽 and IL-6, and the effect was higher than that of the positive control Bay11-7082 (20 𝜇M). In PMA-activated RAW264.7 cells and 293T cells, each concentration of NBT decreased the NF-𝜅B transcriptional activity, with the greatest decrease at 1 mg/mL. Conclusions These results demonstrated the anti-inflammatory effect of NTB water extracts, but further studies such as comparison of anti-inflammatory effects and antioxidant effects by NTB component, comparison of effects according to extraction solvents, and clinical studies are needed.

• Journal of the Korean Electrochemical Society
• /
• v.26 no.1
• /
• pp.11-18
• /
• 2023

As the use of lithium-ion secondary batteries is rapidly increasing due to the rapid growth of the electric vehicle market, the disposal and recycling of spent batteries after use has been raised as a serious problem. Since stored energy must be removed in order to recycle the spent batteries, an effective discharging process is required. In this study, graphite and NCM622 were used as active materials to manufacture coin-type half cells and full cells, and the electrochemical behavior occurring during overdischarge was analyzed. When the positive and negative electrodes are overdischarged respectively using a half-cell, a conversion reaction in which transition metal oxide is reduced to metal occurs first in the positive electrode, and a side reaction in which Cu, the current collector, is corroded following decomposition of the SEI film occurs in the negative electrode. In addition, a side reaction during overdischarge is difficult to occur because a large polarization at the initial stage is required. When the full cell is overdischarged, the cell reaches 0 V and the overdischarge ends with almost no side reaction due to this large polarization. However, if the full cell whose capacity is degraded due to the cycle is overdischarged, corrosion of the Cu current collector occurs in the negative electrode. Therefore, cycled cell requires an appropriate treatment process because its electrochemical behavior during overdischarge is different from that of a fresh cell.

• Journal of Applied Biological Chemistry
• /
• v.65 no.4
• /
• pp.457-462
• /
• 2022

Manganese (Mn) exists in various oxidation states and Mn(II) is the most mobile species of Mn, which is toxic to plants and limits their growth. Therefore, the purpose of this study was to reduce Mn toxicity by immobilizing Mn using various adsorbents including iron oxides and calcium compounds. Ferrihydrite, schwertmannite, goethite were synthesized, which was confirmed by X-ray diffraction. Hematite was purchased and used as Mn adsorbent. Calcium compounds such as CaNO₃, CaSO₄, and CaCO₃ were used to increase pH and oxidize Mn. For Mn adsorption, Mn(II) solution was reacted with four iron oxides, CaNO₃, CaSO₄, and CaCO₃ for 24 hours, filtered, and the remaining Mn concentrations in the solution were analyzed by inductively coupled plasma optical emission spectroscopy. The adsorption rate and adsorption isotherm were calculated. Among iron oxides, the adsorption rate was highest for hematite followed by ferrihyrite, but goethite and schwertmannite did not adsorb Mn. In the case of calcium compounds, the adsorption rate was high in the order of CaCO₃>CaNO₃>CaSO₄. In conclusion, treatment of CaCO₃ was the most effective in reducing Mn toxicity by increasing pH.

• Membrane Journal
• /
• v.32 no.6
• /
• pp.411-426
• /
• 2022

Energy plays a significant role in modern lifestyle because of our extensive reliance over energy-operating devices. Therefore, there is a need for alternative and green energy resources that can fulfill the energy demand. For this, fuel cell (FCs) especially anion exchange membrane fuel cells (AEMFCs) have gained tremendous attention over the other (FCs) due to their fast reaction kinetics without using noble catalyst and allow to use of cheaper polymers with high performance. But lack of highly conductive, chemically, and mechanically stable anion exchange membrane (AEM) still main obstacle to the development of high performance AEMFCs. Therefore, graphene-based polymer composite membranes came into the existence as AEMs for the FCs. The exceptional properties of the graphene help to improve the performance of AEMs. Still, there are lot of challenges in the graphene derivatives based AEMs because of their high tendency of agglomeration in polymer matrix which reduced their potential. To overcome this issue surface modification of graphene derivatives is necessary to restrict their agglomeration and conserved their potential features that can help to improve the performance of AEM. Therefore, this review focus on the surface modification of graphene derivatives and their role in the fabrication of AEMs for the FCs.

• Journal of Life Science
• /
• v.33 no.5
• /
• pp.397-405
• /
• 2023

Although glutathione (GSH) has been shown to play an important role in the prevention of oxidative damage as an antioxidant, studies on immune regulation by it have not been properly conducted. In this study, we investigated whether luthione^®, a reduced GSH, has an immune enhancing effect in murine macrophage RAW 264.7 cells. The results of flow cytometry and immunofluorescence experiments indicated that luthione increased phagocytic activity, a representative function of macrophages, compared to the control cells. According to the results of the cytokine array, the expression of interleukin (IL)-5, IL-1β, and IL-27 was significantly increased in the luthione-treated cells. Luthione also enhanced the production of tumor necrosis factor-α and IL-1β through increased expression of their proteins, and increased release of the immune mediators such as nitric oxide (NO) and prostaglandin E₂ was associated with increased expression of inducible NO synthase and cyclooxygenase-2. In addition, the expression of cluster of differentiation 86, an M1 macrophage marker, was dramatically enhanced in RAW 264.7 cells treated with luthione. Furthermore, as a result of heat map analysis, we found that cytokine signaling 1/3-mediated signal transducer and activator of transcription/Janus tyrosine kinase signaling pathway was involved in the immunomodulatory effect by luthione. In conclusion, our data suggested that luthione could act as a molecular regulator in M1 macrophage polarization and enhance immune capacity by promoting macrophage phagocytic function.

• Journal of Korean Medicine Rehabilitation
• /
• v.33 no.2
• /
• pp.1-18
• /
• 2023

Objectives The purpose of this study was to evaluate the antioxidant, anti-inflammatory and wound healing effects of Samul-tang-ga-dansam water extract (SD) in wound-induced mice. Methods The mice were divided into five groups (n=7): the normal group, the control group, the positive control group, the low-dose SD group and the high-dose SD group. The normal group had no wounds and the other groups were wounded on the back with a leather punch. Distilled water was administered to the control group, 200 mg/kg of vitamin E was administered to the positive control group. In the low-dose SD group and the high-dose SD group, 1.23 g/kg and 2.47 g/kg of SD were administered, respectively. Antioxidant and anti-inflammatory protein levels were evaluated using western blot analysis. Skin tissue was analyzed by H&E, Masson's trichrome staining method. Results Oral administration of the SD significantly reduced the visible skin damage and decreased the reactive oxygen species and ONOO^- activity of the serum. It significantly increased heme oxygenase-1, superoxide dismutase, catalase, GPx-1/2, Nrf2 and Keap-1 which are antioxidant-related factors in skin tissue and reduced NF-κB p65, inducible nitric oxide synthase, cyclooxygenase-2, tumor necrosis factor α, interleukin (IL)-1β, IL-6 which are inflammation-related factors. Also, SD significantly decreased NOX2, p22^phox and p47^phox and increased α-smooth muscle actin and COL1A1 protein expression in fibroblasts involved in connective tissue repair. According to histological examination, the thickened epithelial layer was thinned and collagen fibers were increased to accelerate wound healing. Conclusions It is suggested that Samul-tang-ga-dansam has antioxidant and anti-inflammatory effects and promotes wound tissue repair.