• Title/Summary/Keyword: Reduced Reaction Mechanism

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Convergence Studies of NO Homeostasis in Cellular Signalling (세포의 신호전달 과정에서 NO 항상성에 관한 융복합 연구)

  • Oh, Hee-Kyun;Do, Eun-Young;Park, Hae-Ryoung
    • Journal of Digital Convergence
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    • v.13 no.12
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    • pp.461-467
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    • 2015
  • Saussurea lappa is known for a variety of physiological activities as a component but has not known to show the effect of the cellular signaling pathway. We investigated the anti-inflammatory effects by Saussurea lappa ethanol extract on the LPS(lipopolysaccharide) induced nitric oxide (NO) production by RAW 264.7 cell line. It shows the expressions of iNOS and COX-2 at the transcriptional level (RT-PCR). The Saussurea lappa ethanol extract showed transcriptional expression levels of pro-inflammatory cytokine TNF- and IL-$1{\beta}$ induced by LPS(lipolysaccharide) in RAW264.7 cell line. Saussurea lappa ethanol extract reduced the LPS-induced expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) at the RNA levels in a concentration-dependent manner. The finding that ethanol extract of Saussurea lappa has an influence on NO (nitric oxide) homeostasis in the study of the action mechanism on the macrophage-mediated inflammatory reaction was considered in terms of convergence. And it is to provide an important basis for the prevention and treatment of inflammatory diseases in the future.

Long Noncoding RNA HOXA11-AS Modulates the Resistance of Nasopharyngeal Carcinoma Cells to Cisplatin via miR-454-3p/c-Met

  • Lin, Feng-Jie;Lin, Xian-Dong;Xu, Lu-Ying;Zhu, Shi-Quan
    • Molecules and Cells
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    • v.43 no.10
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    • pp.856-869
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    • 2020
  • To elucidate the mechanism of action of HOXA11-AS in modulating the cisplatin resistance of nasopharyngeal carcinoma (NPC) cells. HOXA11-AS and miR-454-3p expression in NPC tissue and cisplatin-resistant NPC cells were measured via quantitative reverse transcriptase polymerase chain reaction. NPC parental cells (C666-1 and HNE1) and cisplatin-resistant cells (C666-1/DDP and HNE1/DDP) were transfected and divided into different groups, after which the MTT method was used to determine the inhibitory concentration 50 (IC50) of cells treated with different concentrations of cisplatin. Additionally, a clone formation assay, flow cytometry and Western blotting were used to detect DDP-induced changes. Thereafter, xenograft mouse models were constructed to verify the in vitro results. Obviously elevated HOXA11-AS and reduced miR-454-3p were found in NPC tissue and cisplatin-resistant NPC cells. Compared to the control cells, cells in the si-HOXA11-AS group showed sharp decreases in cell viability and IC50, and these results were reversed in the miR-454-3p inhibitor group. Furthermore, HOXA11-AS targeted miR-454-3p, which further targeted c-Met. In comparison with cells in the control group, HNE1/DDP and C666-1/DDP cells in the si-HOXA11-AS group demonstrated fewer colonies, with an increase in the apoptotic rate, while the expression levels of c-Met, p-Akt/Akt and p-mTOR/mTOR decreased. Moreover, the si-HOXA11-AS-induced enhancement in sensitivity to cisplatin was abolished by miR-454-3p inhibitor transfection. The in vivo experiment showed that DDP in combination with si-HOXA11-AS treatment could inhibit the growth of xenograft tumors. Silencing HOXA11-AS can inhibit the c-Met/AKT/mTOR pathway by specifically upregulating miR-454-3p, thus promoting cell apoptosis and enhancing the sensitivity of cisplatin-resistant NPC cells to cisplatin.

Nicotine Suppresses TNF-${\alpha}$ Expression in Human Fetal Astrocyte through the Modulation of Nuclear Factor-${\kappa}B$ Activation

  • Son, Il-Hong;Park, Yong-Hoon;Yang, Hyun-Duk;Lee, Sung-Ik;Han, Sun-Jung;Lee, Jai-Kyoo;Ha, Dae-Ho;Kang, Hyung-Won;Park, Joo-Young;Lee, Sung-Soo
    • Molecular & Cellular Toxicology
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    • v.4 no.2
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    • pp.106-112
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    • 2008
  • Parkinson's disease (PD) progresses severely by a gradual loss of dopaminergic neurons in the substantia nigra (SN). Epidemiological studies showed that the incidences of PD were reduced by smoking of which the major component, nicotine might be neuroprotective. But the function of nicotine, which might suppress the incidences of PD, is still unknown. Fortunately, recently it was reported that a glial reaction and inflammatory processes might participate in a selective loss of dopaminergic neurons in the SN. The levels of tumour necrosis factor (TNF)-${\alpha}$ synthesised by astrocytes and microglia are elevated in striatum and cerebrospinal fluid (CSF) in PD. TNF-${\alpha}$ kills the cultured dopaminergic neurons through the apoptosis mechanism. TNF-${\alpha}$ release from glial cells may mediate progression of nigral degeneration in PD. Nicotine pretreatment considerably decreases microglial activation with significant reduction of TNF-${\alpha}$ mRNA expression and TNF-${\alpha}$ release induced by lipopholysaccharide (LPS) stimulation. Thus, this study was intended to explore the role of nicotine pretreatment to inhibit the expressions of TNF-${\alpha}$ mRNA in human fetal astrocytes (HFA) stimulated with IL-$1{\beta}$. The results are as follows: HFA were pretreated with 0.1, 1, and $10{\mu}g/mL$ of nicotine and then stimulated with IL-$1{\beta}$ (100 pg/mL) for 2h. The inhibitory effect of nicotine on expressions of TNF-${\alpha}$ mRNA in HFA with pretreated $0.1{\mu}g/mL$ of nicotine was first noted at 8hr, and the inhibitory effect was maximal at 12 h. The inhibitory effect at $1{\mu}g/mL$ of nicotine was inhibited maximal at 24 h. Cytotoxic effects of nicotine were noted above $10{\mu}g/mL$ of nicotine. Moreover, Nicotine at 0.1, 1 and $10{\mu}g/mL$concentrations significantly inhibited IL-$1{\beta}$-induced TF-${\kappa}B$ activation. Collectively, these results indicate that in activated HFA, nicotine may inhibit the expression of TNF-${\alpha}$ mRNA through the pathway which suppresses the NF-${\kappa}B$ activation. This study suggests that nicotine might be neuroprotective to dopaminergic neurons in the SN and reduce the incidences of PD.

Electricity Generation and De-contamination Effect for Characteristic Electrode Material in a Microbial Fuel Cell System Using Bay Sediment (MFC의 금속 및 탄소전극에 의한 전기생산 특성과 오염저감 효과)

  • Kwon, Sung-Hyun;Song, Hyung-Jin;Lee, Eun-Mi;Cho, Dae-Chul;Rhee, In-Hyoung
    • Journal of Environmental Science International
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    • v.19 no.8
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    • pp.951-960
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    • 2010
  • Sediment works as a resource for electric cells. This paper was designed in order to verify how sediment cells work with anodic material such as metal and carbon fiber. As known quite well, sediment under sea, rivers or streams provides a furbished environment for generating electrons via some electron transfer mechanism within specific microbial population or corrosive oxidation on the metal surfaces in the presence of oxygen or water molecules. We experimented with one type of sediment cell using different anodic material so as to attain prolonged, maximum electric power. Iron, Zinc, aluminum, copper, zinc/copper, and graphite felt were tested for anodes. Also, combined type of anodes-metal embedded in the graphite fiber matrix-was experimented for better performances. The results show that the combined type of anodes exhibited sustainable electricity production for ca. 600 h with max. $0.57\;W/m^2$ Al/Graphite. Meanwhile, graphite-only electrodes produced max. $0.11\;W/m^2$ along with quite stationary electric output, and for a zinc electrode, in which the electricity generated was not stable with time, therefore resulting in relatively sharp drop in that after 100 h or so, the maximum power density was $0.64\;W/m^2$. It was observed that the corrosive reaction rates in the metal electrodes might be varied, so that strength and stability in the electric performances(voltage and current density) could be affected by them. In addition to that, COD(chemical oxygen demand) of the sediment of the cell system was reduced by 17.5~36.7% in 600 h, which implied that the organic matter in the sediment would be partially converted into non-COD substances, that is, would suggest a way for decontamination of the aged, anaerobic sediment as well. The pH reduction for all electrodes could be a sign of organic acid production due to complicated chemical changes in the sediment.

Protective Effect of a 43 kD Protein from the Leaves of the Herb, Cajanus indicus L on Chloroform Induced Hepatic-disorder

  • Ghosh, Ayantika;Sarkar, Kasturi;Sil, Parames C.
    • BMB Reports
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    • v.39 no.2
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    • pp.197-207
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    • 2006
  • Cajanus indicus is a herb with medicinal properties and is traditionally used to treat various forms of liver disorders. Present study aimed to evaluate the effect of a 43 kD protein isolated from the leaves of this herb against chloroform induced hepatotoxicity. Male albino mice were intraperitoneally treated with 2mg/kg body weight of the protein for 5 days followed by oral application of chloroform (0.75ml/kg body weight) for 2 days. Different biochemical parameters related to physiology and pathophysiology of liver, such as, serum glutamate pyruvate transaminase and alkaline phosphatase were determined in the murine sera under various experimental conditions. Direct antioxidant role of the protein was also determined from its reaction with Diphenyl picryl hydraxyl radical, superoxide radical and hydrogen peroxide. To find out the mode of action of this protein against chloroform induced liver damage, levels of antioxidant enzymes catalase, superoxide dismutase and glutathione-S-transferase were measured from liver homogenates. Peroxidation of membrane lipids both in vivo and in vitro were also measured as malonaldialdehyde. Finally, histopathological analyses were done from liver sections of control, toxin treated and protein pre- and post-treated (along with the toxin) mice. Levels of serum glutamate pyruvate transaminase and alkaline phosphatase, which showed an elevation in chloroform induced hepatic damage, were brought down near to the normal levels with the protein pretreatment. On the contrary, the levels of anti-oxidant enzymes such as catalase, superoxide dismutase and glutathione-S-transferase that had gone down in mice orally fed with chloroform were significantly elevated in protein pretreated ones. Besides, chloroform induced lipid peroxidation was effectively reduced by protein treatment both in vivo and in vitro. In cell free system the protein effectively quenched diphenyl picryl hydrazyl radical and superoxide radical, though it could not catalyse the breakdown of hydrogen peroxide. Post treatment with the protein for 3 days after 2 days of chloroform administration showed similar results. Histopathological studies indicated that chloroform induced extensive tissue damage was less severe in the mice livers treated with the 43 kD protein prior and post to the toxin administration. Results from all these data suggest that the protein possesses both preventive and curative role against chloroform induced hepatotoxicity and probably acts by an anti-oxidative defense mechanism.

Improvement of Au Leaching from Gold Concentrates Using a Microwave and Thiourea-mixed Solvent (마이크로웨이브를 이용한 금정광 내 금 용출 효율 증가 기작)

  • Kim, Bong-Ju;Kwon, Jang-Soon;Koh, Yong-Kwon;Park, Cheon-Young
    • Economic and Environmental Geology
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    • v.53 no.2
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    • pp.159-166
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    • 2020
  • In this research, we investigate the effect of microwave pretreatment on the recovery of gold from the gold concentrates by thiourea leaching. The changes in mineral phases by decomposition of pyrites in the gold concentrates using microwave were observed, and the result of microwave irradiation showed that the temperature of the irradiated sample increases with increasing irradiation time. With the reaction of temperature increases, Sulfur (S) in pyrites was converted to sulfur dioxide (SO2), and then the content of S in the sample was reduced. The analytical results of XRD and SEM-EDS showed that pyrites are converted to magnetite and hematite, and its surfaces are changed to a porous shape where micro-cracks are developed. The Au leaching efficiency from the irradiated gold concentrates using thiourea-mixed solvent increased with the increases of irradiation time and solvent concentration. The experimental results considering leaching parameters indicate that the mechanism of microwave irradiation increases the maximum leaching efficiency and leaching rate of the gold concentrates, and the solvent does a role for the increasing of leaching rate constant.

A Study on the Moderating Effect of Psychological Entitlement on Perceived Organizational Support and Unethical Pro-Organizational Behavior (조직지원인식과 비윤리적 친조직 행동에 있어서 심리적 특권의식의 조절효과에 관한 연구)

  • Weon, Jong-Ha;Lee, Eun-Roung
    • The Journal of the Korea Contents Association
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    • v.20 no.8
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    • pp.598-617
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    • 2020
  • In many enterprises, the extent and the frequency of damages incurred due to the unethical behavior of the members of the organization have not reduced, but rather the magnitude and frequency of damages have been increasing. Research at an organizational level is necessary at this point in time, to investigate the contributing variables that cause this unethical behavior, the measures to manage them, and the control variables that can reduce unethical pro-organizational behavior. Therefore, this study seeks to explore perceived organizational support and psychological entitlement as leading factors of unethical pro-organizational behavior, based on the theory of social exchange, and to examine the reaction mechanism between these variables. This is particularly because a large number of the current labor force belongs to the millennial generation (born after 1978) or Generation Y, and their sense of psychological entitlement has been problematic in their organization. The effect of perceived organizational support on unethical pro-organizational behavior and the effect of psychological entitlement on unethical pro-organizational behavior were examined through a review of existing literature, and an empirical analysis was conducted to investigate the moderating effects of psychological entitlement on perceived organizational support and unethical pro-organizational behavior. A regression analysis was conducted based on the valid data of 185 members of an organization who belong to the millennial generation, and the analysis results showed that a sense of psychological entitlement had a moderating effect between perceived organizational support and unethical pro-organizational behavior. Based on these findings, this paper proposes theoretical and practical implications for unethical pro-organizational behavior and psychological entitlement, and hopes to contribute to expanding research in this area.

Changes of Adsorption Capacity and Structural Properties during in situ Regeneration of Activated Carbon Bed Using Ozonated Water (오존수 산화를 이용한 활성탄 흡착탑의 현장 재생 시 흡착용량 및 구조특성의 변화)

  • Lee, Jinjoo;Lee, Kisay
    • Applied Chemistry for Engineering
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    • v.31 no.3
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    • pp.341-345
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    • 2020
  • An in situ regeneration of activated carbon bed using an ozonated water was studied in order for avoiding the carbon loss, contaminant emission and time consuming for discharge-regeneration-repacking in a conventional thermal regeneration process. Using phenol and polyethylene glycol (PEG) as adsorbates, the adsorption breakthrough and in situ regeneration with the ozonated water were repeated. These organics were supposed to degrade by the oxidation reaction of ozone, regenerating the bed for reuse. As the number of regeneration increased, the adsorption capacity for phenol was reduced, but the change was stabilized showing no further reduction after reaching a certain degree of decrement. The reduction of adsorption capacity was due to the increase of pore size resulting in the decrease of specific surface area during ozonation. The adsorption capacity of phenol decreased after the ozonated regeneration because the in-pore adsorption was prevalent for small molecules like phenol. However, PEG did not show such decrease and the adsorption capacity was constantly maintained after several cycles of the ozonated regeneration probably because the external surface adsorption was the major mechanism for large molecules like PEG. Since the reduction in the pore size and specific surface area for small molecules were proportional to the duration of contact time with the ozonated water, careful considerations of the solute size to be removed and controlling the contact time were necessary to enhance the performance of the ozonated in situ regeneration of activated carbon bed.

Peroxisome Proliferator-Activated Receptor Gamma Agonist Attenuates Liver Fibrosis by Several Fibrogenic Pathways in an Animal Model of Cholestatic Fibrosis

  • Alatas, Fatima Safira;Matsuura, Toshiharu;Pudjiadi, Antonius Hocky;Wijaya, Stephanie;Taguchi, Tomoaki
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.23 no.4
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    • pp.346-355
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    • 2020
  • Purpose: Peroxisome proliferator-activated receptor gamma (PPAR-γ) has a key role in hepatic fibrogenesis by virtue of its effect on the hepatic stellate cells (HSCs). Although many studies have shown that PPAR-γ agonists inhibit liver fibrosis, the mechanism remains largely unclear, especially regarding the cross-talk between PPAR-γ and other potent fibrogenic factors. Methods: This experimental study involved 25 male Wistar rats. Twenty rats were subjected to bile duct ligation (BDL) to induce liver fibrosis, further divided into an untreated group (BDL; n=10) and a group treated with the PPAR-γ agonist thiazolidinedione (TZD), at 14 days post-operation (BDL+TZD; n=10). The remaining 5 rats had a sham operation (sham; n=5). The effect of PPAR-γ agonist on liver fibrosis was evaluated by histopathology, protein immunohistochemistry, and mRNA expression quantitative polymerase chain reaction. Results: Histology and immunostaining showed markedly reduced collagen deposition, bile duct proliferation, and HSCs in the BDL+TZD group compared to those in the BDL group (p<0.001). Similarly, significantly lower mRNA expression of collagen α-1(I), matrix metalloproteinase-2, platelet-derived growth factor (PDGF)-B chain, and connective tissue growth factor (CTGF) were evident in the BDL+TZD group compared to those in the BDL group (p=0.0002, p<0.035, p<0.0001, and p=0.0123 respectively). Moreover, expression of the transforming growth factor beta1 (TGF-β1) was also downregulated in the BDL+TZD group (p=0.0087). Conclusion: The PPAR-γ agonist inhibits HSC activation in vivo and attenuates liver fibrosis through several fibrogenic pathways. Potent fibrogenic factors such as PDGF, CTGF, and TGF-β1 were downregulated by the PPAR-γ agonist. Targeting PPAR-γ activity may be a potential strategy to control liver fibrosis.

Loss of Li2O Caused by ZrO2 During the Electrochemical Reduction of ZrO2 in Li2O-LiCl Molten Salt (Li2O-LiCl 용융염을 이용한 ZrO2의 전기화학적 환원과정에서 발생하는 Li2O의 손실)

  • Park, Wooshin;Hur, Jin-Mok;Choi, Eun-Young;Kim, Jong-Kook
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.10 no.4
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    • pp.229-236
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    • 2012
  • A molten salt technology using $Li_2O$-LiCl has been extensively investigated to recover uranium metal from spent fuels in the field of nuclear energy. In the reduction process, it is an important point to maintain the concentration of $Li_2O$. $ZrO_2$ is inevitably contained in the spent fuels because Zr is one of the main components of fuel rod hulls. Therefore, the fate of $ZrO_2$ in $Li_2O$-LiCl molten salt has been investigated. It was found that $Li_2ZrO_3$ and $Li_4ZrO_4$ were formed chemically and electrochemically and they were not reduced to Zr. The recycling of $Li_2O$ is the key mechanism ruling the total reaction in the electrolytic reduction process. However, $ZrO_2$ will have a role as a $Li_2O$ sink.