• Bulletin of the Korean Chemical Society
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• v.29 no.2
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• pp.389-392
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• 2008

High purity carbon nano fibers/tubes (CNF/Ts) which contain 97% pure graphitic carbon are prepared by a new catalytic method. These carbon nano fibers/tubes are ready to use without any further purification. The striking feature of this method is the production of carbon nano fibers/tubes of narrow distribution range. The developed catalytic method also produces pure hydrogen. An additional advantage of this catalytic method is that catalyst can be reused without reactivation. Ni:Cu catalyst system is embodied into SCHOTT-DURAN filter disc of large pore size (40-100 mm). Due to the production of hydrogen in the reaction catalyst stability is enhanced and deactivation process is considerably slowed down.

• Journal of the Korean Institute of Gas
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• v.27 no.3
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• pp.19-26
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• 2023

Hydrogen, a clean energy source free of COx emissions, is poised to replace fossil fuels, with its usage on the rise. Despite its high energy content per unit mass, hydrogen faces limitations in storage and transportation due to its low storage density and challenges in long-term storage. In contrast, ammonia offers a high storage capacity per unit volume and is relatively easy to liquefy, making it an attractive option for storing and transporting large volumes of hydrogen. While NH₃ decomposition is an endothermic reaction, achieving excellent low-temperature catalytic activity is essential for process efficiency and cost-effectiveness. The study examined the effects of different zeolite types (5A, NaY, ZSM5) on NH₃ decomposition activity, considering differences in pore structure, cations, and Si/Al-ratio. Notably, the 5A zeolite facilitated the high dispersion of Ni across the surface, inside pores, and within the structure. Its low Si/Al ratio contributed to abundant acidity, enhancing ammonia adsorption. Additionally, the presence of Na and Ca cations in the support created medium basic sites that improved N₂ desorption rates. As a result, among the prepared catalysts, the 15 wt%Ni/5A catalyst exhibited the highest NH₃ conversion and a high H₂ formation rate of 23.5 mmol/g_cat·min (30,000 mL/g_cat·h, 600 ℃). This performance was attributed to the strong metal-support interaction and the enhancement of N₂ desorption rates through the presence of medium basic sites.

• Journal of Microbiology and Biotechnology
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• v.18 no.4
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• pp.686-694
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• 2008

The inhibitory effects of 5,6,3',5'-tetramethoxy 7,4'-hydroxyflavone (labeled as p7F) were elucidated on the productions of proinflammatory cytokines as well as inflammatory mediators in human synovial fibroblasts and macrophage cells. p7F inhibited IL-1${\beta}$ or TNF-${\alpha}$ induced expressions of inflammatory mediators (ICAM-1, COX-2, and iNOS). p7F also inhibited LPS-induced productions of nitric oxide and prostaglandin $E_2$ in RAW 264.7 cells. In order to investigate whether p7F would inhibit IL-1 signaling, p7F was added to the D10S Th2 cell line (which is responsive to only IL-1${\beta}$ and thus proliferates), revealing that p7F inhibited IL-1${\beta}$-induced proliferation of D10S Th2 cells in a dose-response manner. A flow cytometric analysis revealed that p7F reduced the intracellular level of free radical oxygen species in RAW 264.7 cells treated with hydrogen peroxide. p7F inhibited IkB degradation and NF-${\kappa}$B activation in macrophage cells treated with LPS, supporting that p7F could inhibit signaling mediated via toll-like receptor. Taken together, p7F has inhibitory effects on LPS-induced productions of inflammatory mediators on human synovial fibroblasts and macrophage cells and thus has the potential to be an anti-inflammatory agent for inhibiting inflammatory responses.

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