• Journal of the Korean Chemical Society
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• v.53 no.3
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• pp.368-376
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• 2009

In this study we investigated and tried to understand problems monitored in an experiment on reactivity of metals in chemistry I. Three problems were discussed. First, the reason that aluminium plate does not react with other metal ions such as zinc, iron and copper was studied and the way to overcome this problem was suggested. Second, the reason that the bubbles were generated when FeS$O_4$(aq) and Zn(s) react was discussed. Third, the precipitates which appeared in the reaction of FeS$O_4$(aq) and Zn(s) were identified. Through reference study and experimental investigation, we could reach the following results. First, aluminium could not react with other metal ions due to the surface oxide layer that is formed very fast and prevents aluminium from reacting with metal ions in solution. This problem could be overcome by allowing a competing reaction of acid and aluminium during the reaction of aluminium and metal ions. Second, the observed bubbles were identified to be hydrogen gas, produced by the reaction between metals and hydronium ion in the solution. Third, black precipitates that were produced on the surface of zinc plate and exhibited magnetic property were characterized to be $Fe_3O_4$(s), and brown precipitates that were produced in the solution phase were to be $Fe_2O_3$(s) by the analysis of X-ray photoelectron spectra.

• Journal of Life Science
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• v.27 no.12
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• pp.1470-1478
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• 2017

The aim of this study was to investigate biological activity and biochemical properties of extracts from Bacillus subtilis-fermented silkworm (Bombyx mori L., SP) powder of different origin (Buan, Namwon, and Boeun). An additional aim was to determine the inhibition of cancer cell (B16-F10, HT-29, LNcaP, and MCF-7) proliferation and nitric oxide (NO) production from lipopolysaccharide (LPS)-induced RAW264.7 cells. Biological activities (${\alpha},{\alpha}^{\prime}$-diphenyl-${\beta}$-picrylhydrazyl [DPPH], free radical scavenging activity, fibrinolytic activity, antiproliferation activity, and anti-inflammatory activity) and biochemical properties (compositional amino acid contents, and mineral contents) were examined in water extracts from silkworm powder and B. subtilis-fermented silkworm powder. The highest amino acid contents were detected in Buan silkworm powder (BU). After fermented, the highest contents were found in B. subtilis-fermented Buan silkworm powder (BBO). The major minerals detected were K, Ca, and Mg. Rates of these minerals, especially those of Na increased after fermented. DPPH radical scavenging activity and fibrinolytic activity were stronger in the fermented group than non-fermented group. DPPH radical scavenging activity and fibrinolytic activity were highest in the extract from BBO. The inhibition activities of LNcaP and MCF-7 cells viability were significantly decreased in the BBO, and there was no inhibition activity in other cancer cells (B16-F10 and HT-29). An SRB assay of the cell viability of RAW 264.7 cells exposed to extracts of silkworm powder and B. subtilis-fermented silkworm powder revealed no toxicity in any of the groups. Compared with the LPS-treated group, the biggest reduction in NO production was detected in the BBO group. Based on these results, extracts from Boeun silkworm powder fermented with B. subtilis could be a candidate material as a dietary supplement for use in healthy functional foods.

• Korean Chemical Engineering Research
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• v.48 no.2
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• pp.185-192
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• 2010

The chemical-looping combustion(CLC) has advantages of no energy loss for separation of $CO_2$ without $NO_x$ formation. This CLC system consists of oxidation and reduction reactors where metal oxides particles are circulating through these two reactors. In the present study, the reaction kinetic equations of iron oxide oxygen carriers supported on bentonite have been determined by the shrinking core model. Based on the reactivity data, design values of solid circulation rate and solids inventory were determined for the rector. Two types of interconnected fluidized bed systems were designed for CLC application, one system consists of a riser and a bubbling fluidized bed, and the other one has a riser and two bubbling fluidized beds. Solid circulation rates were varied to about $30kg/m^2s$ by aeration into a loop-seal. Solid circulation rate increases with increasing aeration velocity and it increases further with an auxiliary gas flow into the loop-seal. As solid circulation rate is increased, solid hold up in the riser increases. A typical gas leakage from the riser to the fluidized bed is found to be less than 1%.

• Journal of Environmental Health Sciences
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• v.27 no.2
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• pp.82-91
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• 2001

This study was carried out to elucidate the protective effect of zinc chloride(ZnCl$_2$) and its mechanism against the immuno-cytotoxicity of methylmercury chloide($CH_3$HgCl). This study was observed in the culture of EMT-6 cells which are originated from mammary adenocarcinoma of Balb/c mouse. Cytotoxicity of metals was measured by cell viability and NO$_2$$^{[-10]}$ , and mitochondrial function was evaluated by adenosine triphosohate (ATP) production. $CH_3$HgCl significantly decreased the sythesis of nitric oxide(NO), ATP and glutathione(GSH) in a dose-dependent manner. ZnCl$_2$ significantly increased the synthesis of GSH in a dose-dependent manner, but synthesis of NO and ATP were not changed. The immuno-cytotoxicity of $CH_3$HgCl was not fully protected when combined addition of ZnCl$_2$, whereas ZnCl$_2$ prior to addition of $CH_3$HgCl completly protected the Hg-induced immuno-cytotoxicity. Similarly, intracellular accumulation of mercury significantly decreased by ZnCl$_2$. Degree of diminution of intracellular mercury was larger in ZnCl$_2$ prior to addition of $CH_3$HgCl than in combined addition of ZnCl$_2$ and $CH_3$HgCl.. Dithiothreitol(DTT) or buthionine sulfoximine(BSO) addition at 50$\mu$M or less, which was not toxic to the cells, did not affect synthesis of NO and ATP. DTT increased intracellular GSH level and DTT pretreatment protected toxicity induced by $CH_3$HgCl as shown complete recover in the NO and ATP values. BSO decreased intracellular GSH level and BSO pretreatment exaggerated toxicity induced by $CH_3$HgCl as shown synergistic reduction in the NO and ATP values. These results indicated that the protective effects of zinc against immuno-cytotoxicity of methylmercury associated with increasing cellular level of GSH. Increased intracellular GSH transports methylmercury to out of cells. In accordance with intracellular level of mercury decreased, immuno-cytotoxicity of methylmercury decreased. These result also suggest that the protective mechanism of zinc against the mercury toxicity would be exerted in the immune system in vivo.

• Applied Biological Chemistry
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• v.38 no.6
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• pp.590-595
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• 1995

To examine the characteristics of antioxidative compounds from Capsella bursa-pastoris, ethanol extracts were separated into five organic solvent fractions; hexane(Fr.H), diethyl ether (Fr.E), ethyl acetate(Fr.EA), butanol (Fr.B), and water(Fr.D) fractions. Fr.B showed the greatest electron donating ability and inhibitory effect on lipid peroxidation. Whereas Fr.E had the most excellent activity in the superoxide radical scavenging activity by xanthine/xanthine oxidase-cytochrome c reduction system. The inhibitory effect of each fraction on xanthine oxidase was also measured. Fr.E had the strongest inhibitory effect on xanthine oxidase and $IC_{50}$ was $5.65\;{\mu}g$. The results indicate that the superoxide radical scavenging activity of Fr.E is caused by the inhibitory effect on radical generating system of xanthine oxidase. Also the order of inhibitory effect on xanthine oxidase was Fr.B

• Membrane Journal
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• v.25 no.6
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• pp.496-502
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• 2015

Facilitated transport is one of the possible solutions to simultaneously improve permeability and selectivity, which is challenging in conventional polymer-based membranes. Olefin/paraffin separation using facilitated transport membrane has received much attention as an alternative solution to the conventional distillation process. Herein, we report olefin separation composite membranes based on the polymer blends containing $AgBF_4/Al(NO_3)_3$ mixed salts. Free radical polymerization process was used to synthesize an amphiphilic graft copolymer of poly(dimethyl siloxane)-graft- poly(ethylene glycol) methyl ether methacrylate (PDMS-g-POEM). In addition, poly(ethylene oxide) (PEO) was introduced to the PDMS-g-POEM graft copolymer to form polymer blends with various ratios. The propylene/propane mixed-gas selectivity and permeance reached up to 5.6 and 10.05 GPU, respectively, when the PEO loading was 70 wt% in polymer blend. The improvement of olefin separation performance was attributed to the olefin facilitating silver ions as well as the highly permeable blend matrix. The stabilization of silver ions in the composite membrane was achieved through the introduction of $Al(NO_3)_3$ which suppressed the reduction of silver ions to silver particles.

• Journal of Oriental Physiology
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• v.14 no.2 s.20
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• pp.179-187
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• 1999

To investigate how Jagamchotang provent cellular injury by a certain starting point on reperfusion injury after ischemia in myocardial cell, conducted MTT assay, LM stydy and measured LDH secretion, heart rate and nitric oxide(NO), and got the following results. 1. Jagamchotang did not injure cells even in $20{\mu}g/ml$. 2. Jaganchotang repressed the toxicity of mitochondria and cell membrane in reperfusing after ischemia and repressed the contraction of promontory of myocardial cell and reduction of the number of cells. Also maintained regular heart rate and reduced the number of heart rate. 3. Synthesis of NO by Jagamchotang in ischemia increased 1.9 times than a control. 4. When reperfusing with sodium nitropruside (SNO), NO donor in ischemia repressed the toxicity of mitochondria as the case of reperfusing with Jagamchotang in ischemia. Therefore, putting these findings together, it. can be said the effect of Jagamchotang in ischemia will be closely related with generation of NO.

• Resources Recycling
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• v.29 no.1
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• pp.81-88
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• 2020

Recovery of gallium and indium from waste light emitting diodes has been emphasized gradually owing to high content of gallium and indium. This study was established the recovery of gallium (Ga³⁺) and indium (In³⁺) from waste gallium nitride was contained in waste light-emitting diodes. The procedure was divided into the following steps; characteristic analysis, alkaline roasting, and leaching. In characteristic analysis part, the results were used as a theoretical basis for the acid leaching part, and the chemical composition of waste light emitting diodes is 70.32% Ga, 5.31% Si, 2.27% Al and 2.07% In. Secondly, with reduction of non-metallic components by alkaline roasting, gallium nitride was reacted into sodium gallium oxide, in this section, the optimal condition of alkaline roasting is that the furnace was soaked at 900℃ for 3 hours with mixing Na₂CO₃. Next, leaching of waste light emitting diodes was extremely important in the process of recovery of gallium and indium. The result of leaching efficiency was investigated on the optimal condition accounting for the acid agent, concentration of acid, the ratio of liquid and solid, and reaction time. The optimal condition of leaching procedures was carried out for 2.0M of HCl liquid-solid mass ratio of 30 ml/g in 32minutes at 25℃ and about 96.88% Ga and 96.61% In were leached.

• Journal of Ginseng Research
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• v.39 no.1
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• pp.61-68
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• 2015

Background: Korean Red Ginseng (KRG) is a representative traditional herbal medicine with many different pharmacological properties including anticancer, anti-atherosclerosis, anti-diabetes, and anti-inflammatory activities. Only a few studies have explored the molecular mechanism of KRG-mediated anti-inflammatory activity. Methods: We investigated the anti-inflammatory mechanisms of the protopanaxadiol saponin fraction (PPD-SF) of KRG using in vitro and in vivo inflammatory models. Results: PPD-SF dose-dependently diminished the release of inflammatory mediators [nitric oxide (NO), tumor necrosis factor-${\alpha}$, and prostaglandin $E_2$], and downregulated the mRNA expression of their corresponding genes (inducible NO synthase, tumor necrosis factor-${\alpha}$, and cyclooxygenase-2), without altering cell viability. The PPD-SF-mediated suppression of these events appeared to be regulated by a blockade of p38, c-Jun N-terminal kinase (JNK), and TANK (TRAF family member-associated NF-kappa-B activator)-binding kinase 1 (TBK1), which are linked to the activation of activating transcription factor 2 (ATF2) and interferon regulatory transcription factor 3 (IRF3). Moreover, this fraction also ameliorated HCl/ethanol/-induced gastritis via suppression of phospho-JNK2 levels. Conclusion: These results strongly suggest that the anti-inflammatory action of PPD-SF could be mediated by a reduction in the activation of p38-, JNK2-, and TANK-binding-kinase-1-linked pathways and their corresponding transcription factors (ATF2 and IRF3).

• Food Science and Preservation
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• v.25 no.1
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• pp.90-97
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• 2018

Peach seeds contain a large amount of phenolic components and exhibit excellent physiological effects in various diseases. We examined the antioxidant effects of stone and seed of three peach cultivars (Miwhang, MH; Kanoiwa hakuto, KH; and Cheonhong, CH) by 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, ferric reducing activity of plasma (FRAP) assay, and cupric ion reducing antioxidant capacity (CUPRAC) reduction. The results showed that the stone extracts of CH had higher levels of total phenols and flavonoids than those of the other cultivars do, and the stone extracts of KH and CH have the potential to reduce DPPH, FRAP, and CUPRAC activities. In addition, we found that KH, MH, and CH stone extracts decreased nitric oxide generation in RAW 264.7 and BV2 cells. The total phenol and flavonoid contents had no significant correlation with anti-oxidant activities. On the other hand, the anti-inflammatory activity had a low linear correlation with anti-oxidant activities and total phenol and flavonoid contents. The present results suggest that the correlation between antioxidant and anti-inflammatory effects of stone and seed, and the appropriate combination of the stone and seed extracts could be used as an anti-inflammatory treatment and prevention material, respectively.