• Bulletin of the Korean Chemical Society
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• 제24권1호
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• pp.27-31
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• 2003

A Polythiophene-quinoline/glassy carbon (PTQ/GC) modified electrode was developed for the determination of trace mercury in industrial waste water, natural water, soil, and other media. The electrode was prepared by the cyclic voltammetric polymerization of thiophene and quinoline on glassy carbon (GC) electrode by the potential application from -0.6 V to +2.0 V (50 mV/sec) in a solution of 0.1 M thiophene, quinoline and tetrabutyl ammonium perchlorate (TBAP) in acetonitrile. Optimum thickness of the polymer membrane on the GC electrode was obtained with 20 repeated potential cyclings. The redox behavior of Cu(Ⅱ) and Hg(Ⅱ) were almost identical on this electrode. The addition of 4-(2-pyridylazo)resorcinol (PAR) to the solution containing Cu(Ⅱ) and Hg(Ⅱ) allowed the separation of the components due to the formation of the Cu(Ⅱ)-PAR complex reduced at -0.8V, which was different from the Hg(Ⅱ) reduced at -0.5 V on a saturated calomel electrode (SCE). The calibration graph of Hg(Ⅱ) shows good linear relationship with the correlation factor of 0.9995 and the concentration gradient of 0.33 ㎂/㎠/ppb down to 0.4 ppb Hg. The method developed was successfully applied to the determination of mercury in samples such as river, waste water, and sea water.

• 대한화학회지
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• 제42권6호
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• pp.664-671
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• 1998

유기 전도성 고분자들중 전도성이 뛰어나고 전기화학적으로 중합이 용이하며 안정성이 뛰어난 피로고분자(ppy)는 산화-환원 활성자리에 회합되는 이온종에 따라서 피막의 형태학적 구조가 다양하다. 그러나 공기중에서 쉽게 노화하며 잘 부서지고 물과 친하지 않은 단점이 있다. 이를 개선하기 위하여 이 다공성 ppy 피막에 높은 개시전위를 갖는 퓨란고분자(pfu)를 끼워심기 중합한 Pt/ppy/pfu(x)전극을 제작하여 그 전기화학적 성질들을 순환전압전류법과 전기호학적 임피던스법으로 조사하였다. 이 때 사용된 도판트 이온은 $PF_6^-,\; BF_4^-$, 그리고 $ClO_4^-$이온 이였으며, pfu의 조성은 ppy에 대하여 0∼1.10 범위였는데 그 조성이 0.1∼0.2의 범위에 있을 때 가장 좋은 산화환원 특징을 나타냈다. 또, $PF_6^-$ 이온이 도우핑되었을 때 전하전달 저항은 다른 이온들로 중합된 것에 비하여 40배정도 낮았으며, 이 중층의 용량은 다른 두 종에 비하여 20배정도 큰 값을 보였다. 전하전달은 주파수의 변화에 영향을 받으며 물질전달에 의한 Warburg 임피던스 항이 포함되는 등가회로를 갖는다.

• 생명과학회지
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• 제28권1호
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• pp.43-49
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• 2018

Chrysoeriol은 alfalfa에서 주로 발견되는, 식물계에 많이 분포하고 있는 flavone으로 전통의학에서 소화불량, 천식, 비뇨기계 이상의 치료에 사용되어 왔다. 최근의 연구에서는 항염증 효과가 있는 것으로 밝혀졌으나 항산화 효과에 대한 분석은 없었다. 본 연구에서는 chrysoeriol의 항산화 효과와 그 분자적 기전을 RAW 264.7 cell에서 세포생존율, reactive oxygen species (ROS)와 Western blot분석을 통해 알아보고자 하였다. Chrysoeriol은 lipopolysaccharide(LPS)에 의해 발생한 ROS를 세포독성없이 농도의존적으로 제거하였다. 그리고 항산화효과를 보이는 2상 효소 중 하나인 heme oxygenase (HO)-1의 발현을 강하게 유도하였고, 그와 동시에 전사인자인 Nrf2의 핵내 이동도 촉진하는 것으로 밝혀졌다. 특히, 산화스트레스에 대한 세포내 산화환원항상성 유지에 중요한 역할을 하고 있는 것으로 알려진 mitogen activated protein kinase (MAPK)와 phosphoinositide 3-kinase (PI3K)의 분석결과, chrysoeriol은 extracellular signal regulated kinase (ERK), c-Jun NH2-terminal kinase (JNK)와 p38의 인산화를 통해 HO-1의 발현을 유도하는 것으로 나타났다. HO-1에 의한 항산화 효과를 확인하기 위하여 chrysoeriol을 전처리한 후 t-BHP에 의한 산화 스트레스에 세포를 노출시킨 결과, chrysoeriol 처리에 의해 세포사멸이 줄어드는 것을 확인하였고, HO-1의 유도제와 억제제의 처리에 따라 세포생존율 또한 조절되는 것을 확인할 수 있었다. 따라서, chrysoeriol은 HO-1의 발현을 유도하여 항산화 효과를 높이고 이것은 Nrf2/MAPK 신호전달 체계에 의한다는 것을 알 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제32권6호
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• pp.2058-2062
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• 2011

The effect of the addition of ionic liquids with four different cations (imidazolium, pyrrolidinium, piperidinium and pyridinium) on the performance of dye-sensitized $TiO_2$ solar cells based on electrolytes containing a t-butylpyridine (TBP) in 3-methoxypropionitrile (MPN) was studied. A total of 18 ionic liquids with mono-, di- and tri-alkyl derivatives were used in the present study, and among them a pyridinium cation with a mono-alkyl group showed better cell efficiency than the others. The best photoelectric conversion efficiency, 7.213%, was obtained using 1-hexylpyridinium iodide with an open-circuit photovoltage ($V_{oc}$) = 0.731 V, a short-circuit photocurrent density ($J_{sc}$) = 16.175 $mA/cm^2$, and a fill factor (ff) = 0.610 under AM1.5 and 100 $mW/cm^2$ illumination.

• Asian-Australasian Journal of Animal Sciences
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• 제33권7호
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• pp.1167-1179
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• 2020

Objective: This study was conducted to fathom the underlying mechanisms of nutrition intervention and redox sensitive transcription factors regulated by Antrodia cinnamomea fermented product (FAC) dietary supplementation in broiler chickens. Methods: Four hundreds d-old broilers (41±0.5 g/bird) assigned to 5 groups were examined after consuming control diet, or control diet replaced with 5% wheat bran (WB), 10% WB, 5% FAC, and 10% FAC. Liver mRNA expression of antioxidant, inflammatory and lipid metabolism pathways were analyzed. Prostaglandin E2 (PGE₂) concentration in each group were tested in the chicken peripheral blood mononuclear cells (cPBMCs) of 35-d old broilers to represent the stress level of the chickens. Furthermore, these cells were stimulated with 2,2'-Azobis(2-amidinopropane) dihydrochloride (AAPH) and lipopolysaccharide (LPS) to evaluate the cell stress tolerance by measuring cell viability and oxidative species. Results: Heme oxygenase-1, glutathione S-transferase, glutamate-cysteine ligase, catalytic subunit, and superoxide dismutase, and nuclear factor (erythroid-derived 2)-like 2 (Nrf2) that regulates the above antioxidant genes were all up-regulated significantly in FAC groups. Reactive oxygen species modulator protein 1 and NADPH oxygenase 1 were both rather down-regulated in 10% FAC group as comparison with two WB groups. Despite expressing higher level than control group, birds receiving diet containing FAC had significantly lower expression level in nuclear factor-kappa B (NF-κB) and other genes (inducible nitric oxide synthase, tumor necrosis factor-α, interleukin-1β, nucleotide-binding domain, leucine-richcontaining family, pyrin domain-containing-3, and cyclooxygenase 2) involving in inflammatory pathways. Additionally, except for 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase that showed relatively higher in both groups, the WB, lipoprotein lipase, Acetyl-CoA carboxylase, fatty acid synthase, fatty acid binding protein, fatty acid desaturase 2 and peroxisome proliferator-activated receptor alpha genes were expressed at higher levels in 10% FAC group. In support of above results, promoted Nrf2 and inhibited NF-κB nuclear translocation in chicken liver were found in FAC containing groups. H₂O₂ and NO levels induced by LPS and AAPH in cPBMCs were compromised in FAC containing diet. In 35-d-old birds, PGE₂ production in cPBMCs was also suppressed by the FAC diet. Conclusion: FAC may promote Nrf2 antioxidant pathway and positively regulate lipid metabolism, both are potential inhibitor of NF-κB inflammatory pathway.

• Toxicological Research
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• 제23권3호
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• pp.207-214
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• 2007

Chronic oxidative stress produced by exposure to environmental chemicals or pathophysiological states can lead animals to aging, carcinogenesis and degenerative diseases. Indirect antioxidative mechanisms, in which natural or synthetic agents are used to coordinately induce the expression of cellular antioxidant capacity, have been shown to protect cells and organisms from oxidative damages. Electrophile and free radical detoxifying enzymes, which were originally identified as the products of genes induced by cancer chemopreventive agents, are members of this protective system. The NFE2 family transcription factor Nrf2 was found to govern expression of these detoxifying enzymes, and screening for Nrf2-regulated genes has identified many gene categories involved in maintaining cellular redox potential and protection from oxidative damage as Nrf2 downstream genes. Further, studies using Nrf2-deficient mice revealed that these mutant mice showed more susceptible phenotypes towards exposure to environmental chemicals/carcinogens and in oxidative stress related disease models. With the finding that cancer chemopreventive efficacy of indirect antioxidants (enzyme inducers) is lost in the absence of Nrf2, a central role of Nrf2 in the antioxidative protective system has been firmly established. Promising results from cancer prevention clinical trials using enzyme inducers propose that pharmacological interventions that modulate Nrf2 can be an effective strategy to protect tissues from oxidative damage.

• BMB Reports
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• 제53권2호
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• pp.106-111
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• 2020

Glutaredoxin 1 (GLRX1) has been recognized as an important regulator of redox signaling. Although GLRX1 plays an essential role in cell survival as an antioxidant protein, the function of GLRX1 protein in inflammatory response is still under investigation. Therefore, we wanted to know whether transduced PEP-1-GLRX1 protein inhibits lipopolysaccharide (LPS)- and 12-O-tetradecanoyl phorbol-13-acetate (TPA)-induced inflammation. In LPS-exposed Raw 264.7 cells, PEP-1-GLRX1 inhibited cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), activation of mitogen activated protein kinases (MAPKs) and nuclear factor-kappaB (NF-κB) expression levels. In a TPA-induced mouse-ear edema model, topically applied PEP-1-GLRX1 transduced into ear tissues and significantly ameliorated ear edema. Our data reveal that PEP-1-GLRX1 attenuates inflammation in vitro and in vivo, suggesting that PEP-1-GLRX1 may be a potential therapeutic protein for inflammatory diseases.

• BMB Reports
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• 제46권5호
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• pp.258-263
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• 2013

In the current study, we explored the effect of LDR on the activation of Nrfs transcription factor involved in cellular redox events. Experiments were carried out utilizing 0.05 and 0.5 Gy X-ray irradiated normal human skin fibroblast HS27 cells. The results showed LDR induced Nrf1 and Nrf2 activation and expression of antioxidant genes HO-1, Mn-SOD, and NQO1. In particular, 0.05 Gy-irradiation increased only Nrf1 activation, but 0.5 Gy induced both Nrf1 and Nrf2 activation. LDR-mediated Nrf1/2 activation was accompanied by reactive species (RS) generation and $Ca^{2+}$ flux. This effect was abolished in the presence of N-acetyl-cysteine and BAPTA- AM. Furthermore, Nrf1/2 activation by LDR was suppressed by PD98059, an inhibitor of ERK1/2. In conclusion, LDR induces Nrf1 and Nrf2 activation and expression of Nrf-regulated antioxidant defense genes through RS and $Ca^{2+}$/ERK1/2 pathways, suggesting new insights into the molecular mechanism underlying the beneficial role of LDR in HS27 cells.

• Korean Journal of Acupuncture
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• 제29권1호
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• pp.37-46
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• 2012

Objectives : The gnarl of Pinus densiflora, called Songjeol in Korea, has been used as a medicinal herb for the treatment of inflammatory-related diseases such as arthralgia, myalgia and bruise. However, the molecular actions and mechanisms have not been clearly investigated. The aim of this study was to clarify the anti-inflammatory activity of Pinus densiflora gnarl pharmacopuncture (PDGP) in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Methods : Cytotoxicity was assessed by XTT assay. The amount of nitric oxide (NO) production was determined by nitrite assay. The mRNA expressions of interleukin-$1{\beta}$ (IL-$1{\beta}$), interleukin-6 (IL-6), cyclooxygenase-2 (COX-2) and heme oxygenase-1 (HO-1) were analyzed by RT-PCR. Reactive oxidative species (ROS) generation was measured using the fluorescence microscopy. In addition, inducible nitric oxide synthase (iNOS) and redox factor-1 (Ref-1) protein expressions were detected by Western blotting. Results : PDGP inhibited NO production and ROS generation in LPS-stimulated RAW264.7 cells. At the mRNA level, PDGP suppressed IL-$1{\beta}$, IL-6 and COX-2 expression. On the other hand, PDGP induced HO-1 mRNA expression. Furthermore, PDGP suppressed iNOS and Ref-1 protein expression. Conclusions : This result suggests that PDGP can act as a suppressor agent on NO and iNOS through induction of HO-1, and play an useful role in blocking inflammatory responses.

• Macromolecular Research
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• 제17권12호
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• pp.963-968
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• 2009

Liquid crystal (LC; E7 and/or ML-0249)-embedded, poly(vinylidenefluoride-co-hexafluoropropylene) (PVdF-co-HFP)-based, polymer electrolytes were prepared for use in dye-sensitized solar cells (DSSCs). The electrolytes contained 1-methyl-3-propylimidazolium iodide (PMII), tetrabutylammonium iodide (TBAI), and iodine ($I_2$), which participate in the $I_3^-/I^-$ redox couple. The incorporation of photochemically stable PVdF-co-HFP in the DSSCs created a stable polymer electrolyte that resisted leakage and volatilization. DSSCs, with liquid crystal(LC)-embedded PVdF-co-HFP-based polymer electrolytes between the amphiphilic ruthenium dye N719 absorbed to the nanocrystalline $TiO_2$ photoanode and the Pt counter electrode, were fabricated. These DSSCs displayed enhanced redox couple reduction and reduced charge recombination in comparison to that fabricated from the conventional PVdF-co-HFP-based polymer electrolyte. The behavior of the polymer electrolyte was improved by the addition of optimized amounts of plasticizers, such as ethylene carbonate (EC) and propylene carbonate (PC). The significantly increased short-circuit current density ($J_{sc}$, $14.60\;mA/cm^2$) and open-circuit voltage ($V_{oc}$, 0.68 V) of these DSSCs led to a high power conversion efficiency (PCE) of 6.42% and a fill factor of 0.65 under a standard light intensity of $100\;mW/cm^2$ irradiation of AM 1.5 sunlight. A DSSC fabricated by using E7-embedded PVdF-co-HFP-based polymer electrolyte exhibited a maximum incident photon-to-current conversion efficiency (IPCE) of 50%.