• Archives of Pharmacal Research
• /
• 제27권12호
• /
• pp.1245-1252
• /
• 2004

Although ascorbate (vitamin C) has been shown to have anti-cancer actions, its effect on human hepatoma cells has not yet been investigated, and thus, the exact mechanism of this action is not fully understood. In this study, the mechanism by which ascorbate induces apoptosis using HepG2 human hepatoblastoma cells is investigated. Ascorbate induced apoptotic cell death in a dose-dependent manner in the cells, was assessed through flow cytometric analysis. Contrary to expectation, ascorbate did not alter the cellular redox status, and treatment with antioxidants (N-acetyl cysteine and N,N-diphenyl-p-phenylenediamine) had no influence on the ascorbate-induced apoptosis. However, ascorbate induced a rapid and sustained increase in intracellular $Ca^{2+}$ concentration. EGTA, an extracellular $Ca^{2+}$ chelator did not significantly alter the ascorbate-induced intracellular $Ca^{2+}$ increase and apoptosis, whereas dantrolene, an intracellular $Ca^{2+}$ release blocker, completely blocked these actions of ascorbate. In addition, phospholipase C (PLC) inhibitors (U-73122 and manoalide) significantly suppressed the intracellular $Ca^{2+}$ release and apoptosis induced by ascorbate. Collectively, these results suggest that ascorbate induced apoptosis without changes in the cellular redox status in HepG2 cells, and that the PLC-coupled intracellular $Ca^{2+}$ release mechanism may mediate ascorbate-induced apoptosis.

• Bulletin of the Korean Chemical Society
• /
• 제28권9호
• /
• pp.1455-1456
• /
• 2007

• 한국세라믹학회지
• /
• 제54권6호
• /
• pp.535-538
• /
• 2017

Here we report the tunable electrical properties and chemical sensor of single-walled carbon nanotubes (SWCNTs) network-based devices with a functionalization technique. Formation of highly aligned SWCNT structures is made on $SiO_2/Si$ substrates using a template-based fluidic assembly process. We present a Platinum (Pt)-nanocluster decoration technique that reduces the resistivity of SWCNT network-based devices. This indicates the conversion of the semiconducting SWCNTs into metallic ones. In addition, we present the Hydrogen Sulfide ($H_2S$) gas detection by a redox reaction based on SWCNT networks functionalized with 2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO) as a catalyst. We summarize current changes of devices resulting from the redox reactions in the presence of $H_2S$. The semiconducting (s)-SWCNT device functionalized with TEMPO shows high gas response of 420% at 60% humidity level compared to 140% gas response without TEMPO functionalization, which is about 3 times higher than bare s-SWCNT sensor at the same RH. These results reflect promising perspectives for real-time monitoring of $H_2S$ gases with high gas response and low power consumption.

• Molecules and Cells
• /
• 제39권1호
• /
• pp.46-52
• /
• 2016

It is increasingly apparent that nature evolved peroxiredoxins not only as $H_2O_2$ scavengers but also as highly sensitive $H_2O_2$ sensors and signal transducers. Here we ask whether the $H_2O_2$ sensing role of Prx can be exploited to develop probes that allow to monitor intracellular $H_2O_2$ levels with unprecedented sensitivity. Indeed, simple gel shift assays visualizing the oxidation of endogenous 2-Cys peroxiredoxins have already been used to detect subtle changes in intracellular $H_2O_2$ concentration. The challenge however is to create a genetically encoded probe that offers real-time measurements of $H_2O_2$ levels in intact cells via the Prx oxidation state. We discuss potential design strategies for Prx-based probes based on either the redoxsensitive fluorophore roGFP or the conformation-sensitive fluorophore cpYFP. Furthermore, we outline the structural and chemical complexities which need to be addressed when using Prx as a sensing moiety for $H_2O_2$ probes. We suggest experimental strategies to investigate the influence of these complexities on probe behavior. In doing so, we hope to stimulate the development of Prx-based probes which may spearhead the further study of cellular $H_2O_2$ homeostasis and Prx signaling.

• Asian-Australasian Journal of Animal Sciences
• /
• 제24권12호
• /
• pp.1681-1689
• /
• 2011

The beneficial effects of tea catechins (TCs) are related not only to their antioxidant potential but also to the improvement of animal meat quality. In this study, we assessed the effects of dietary TC supplementation on plasma biochemical parameters, hormone responses, and glutathione redox status in goats. Forty Liuyang goats were randomly divided into four equal groups (10 animals/group) that were assigned to four experimental diets with TC supplementation at 4 levels (0, 2,000, 3,000 or 4,000 mg TC/kg DM feed). After a 60-day feeding trial, all goats were slaughtered and sampled. Dietary TC treatment had no significant effect on blood biochemical parameters, however, low-density lipoprotein cholesterol (p<0.001), triglyceride (p<0.01), plasma urea nitrogen (p<0.01), and glucose (p<0.001) decreased and total protein (p<0.01) and albumin (p<0.05) increased with the feeding time extension, and day 20 was the turning point for most of changes. Interactions were found in glutathione (p<0.001) and the ratio of reduced and oxidized glutathione (p<0.05) in whole blood between treatment and feeding time. Oxidized glutathione in blood was reduced (p<0.05) by 2,000 mg TC/kg feed supplementation, and a similar result was observed in longissimus dorsi muscle. Though plasma glutathione peroxidase (p<0.01) and glutathione reductase (p<0.05) activities were affected by treatment and feeding time interactions, and glutathione S-transferases activity increased with feeding day extension, no changed values appeared in longissimus dorsi muscle. In conclusion, dietary TC supplementation affected the concentrations of some blood metabolites and accelerated GSH depletion in the blood of goats. In terms of less high-density lipoprotein cholesterol, the highest insulin and IGF-I concentrations, the highest ratio of reduced and oxidized glutathione in plasma, the dosage of 2,000 mg TC/kg feed might be desirable for growing goats to prevent glutathione depletion and keep normal physiological metabolism.

• 에너지공학
• /
• 제24권3호
• /
• pp.89-95
• /
• 2015

레독스흐름전지의 전극으로 사용하기 위해 (주)CNF에서 제조한 탄소펠트를 여러 가지 온도에서 열처리하여 실험하였다. 열처리 조건에 따른 탄소펠트의 물성특성을 파악하기 위하여 BET(비표면적)와 무게감소를 측정하였고 표면특성을 살펴보기 위하여 주사전자현미경(SEM)과 XPS 분석을 실시하였다. 또한 전기저항, CV(cyclic voltammetry), RFB 충방전 성능 통해 열처리 조건에 따른 전극특성에 미치는 영향을 살펴보았다. SEM, BET분석을 통하여 탄소펠트 표면의 물성 변화를 확인하였고, XPS 분석을 통해 $550^{\circ}C$에서 1시간 열처리한 탄소펠트의 표면에 산소 관능기가 가장 많이 부가된 것을 확인하였다. CV 실험을 수행한 결과 $550^{\circ}C$ 열처리 전극의 활성면적이 가장 컸다. $400^{\circ}C$, $500^{\circ}C$, $550^{\circ}C$에서 열처리한 탄소펠트를 이용하여 바나듐 레독스흐름전지를 구성하고 충-방전 실험을 실시한 결과 충-방전 에너지효율이 $400^{\circ}C$ 열처리 전극의 경우 72.9%, $500^{\circ}C$ 열처리 전극의 경우 79.8%, $550^{\circ}C$ 열처리 전극의 경우 79.8%로 $550^{\circ}C$ 열처리 전극이 가장 우수하였다.

• 한국토양비료학회지
• /
• 제40권6호
• /
• pp.495-500
• /
• 2007

본 시험은 벼 종이멀칭이앙 시 유기물원 및 유기물원과 완효성비료 조합 시 벼 생육, 잡초방제, 토양에 미치는 영향을 구명하고자 경기도 수원에 소재하는 작물과학원 벼시험포장 강서통에서 대안벼를 2004년 5월 28일에 중묘를 종이멀칭기계 이앙하였다. 시용한 유기물원은 퇴비, 볏짚 및 청예호밀을 투입하였다. 시용한 퇴비의 생중은 $10,000kg\;ha^{-1}$이고 C/N율은 17.5, 볏짚의 생중은 $10,000kg\;ha^{-1}$이고 C/N율은 44.2, 청예호밀은 생초중 $11,380kg\;ha^{-1}$이고 C/N율은 42.6이었다. 완효성 비료와 유기물원과 혼합 시 완효성비료의 시용량은 관행질소 시비량의 80%를 기준으로 하여 시용하였다. 완효성비료의 비종은 LCU (Latex Coated Urea, 21-7-9)복비를 시용하였다. 피복재료는 생분해성 폴리에스터 (PES $10{\mu}m$)+재생지를 이용하여 피복하였다. 유기물 시용 후 벼 종이멀칭이앙 시모의 결주율은 관행이앙과 큰 차이가 없었다. 잡초발생 및 방제가는 호밀이 투입된 구에서 잡초발생이 적었고 방제가도 높은 경향이었다. 주요시기별 토양의 산화환원전위는 볏짚+완효성 비료 80%구가 분얼기에 가장 낮았다. 볏짚과 퇴비 단용구는 유수형성기까지 산화환원전위가 감소하는 경향이었다. 주요시기별 토양 중 $NH_4{^+}-N$는 분얼기에는 청예호밀+완효성 80%구가 가장 높았고 퇴비시용구에서 유수형성기까지 용출이 되는 경향이었다. 벼 수량은 청예호밀+완효성 80%구와 퇴비+완효성 80%구가 관행과 통계적으로 차이가 없었다. 볏짚+완효성 80%구는 수량이 통계적으로 유의하게 감소하였다.

• 한국환경농학회지
• /
• 제29권4호
• /
• pp.336-342
• /
• 2010

환원상태가 발달된 담수상태의 토양이나 습지생태계에서 ${NO_3}^-$는 환원상태의 진전을 지연시키는 완충역할을 할 수 있다. 논토양에서 ${NO_3}^-$가 Fe(III) 환원과 그에 따른 P의 가용화에 미치는 영향과 함께 질산화작용억제가 벼의 N, P 흡수 및 생육에 미치는 영향을 조사하였다. 담수 후 10 cm 깊이 토양의 산화환원전위 변화는 N 비료처리별로 현저하게 달리 나타났으며, 질산화작용이 억제된 요소+N-serve 처리에서는 -100 mV 이하로 낮아졌으나 $KNO_3$처리의 경우에는 0 mV 이상으로 유지되었다. 이러한 현상은 질소비료 처리별로 ${NO_3}^-$에 의한 redox buffer 작용 유무에 따라서 결정되는 것이다. N-serve 처리를 통하여 질산화작용을 억제시키면 ${NO_3}^-$에 의한 redox buffer 작용이 없어지므로 토양의 환원현상이 크게 촉진될 수 있는 것이다. 따라서 요소+N-serve 처리에서는 다른 처리에 비하여 Fe(III)의 환원과 함께 토양 용액의 ${PO_4}^{3-}$ 함량이 현저히 증가하였다. 질산화저해제와 함께 요소를 처리한 경우 토양 용액중의 N 및 P 함량과 함께 벼 유묘 지상부의 N과 P 함량이 가장 높았음에도 불구하고 그 생장은 가장 불량하였다. 이와 같이 요소+N-serve 처리에서 나타난 벼 유묘 생장 저해 현상은 과도한 Fe(II)의 용출과 그에 따른 벼 유묘의 Fe 과잉흡수에 기인하는 것으로 판단된다.

• The Plant Pathology Journal
• /
• 제35권6호
• /
• pp.609-622
• /
• 2019

Sound vibration (SV) treatment can trigger various molecular and physiological changes in plants. Previously, we showed that pre-exposure of Arabidopsis plants to SV boosts its defense response against Botrytis cinerea fungus. The present study was aimed to investigate the changes in the proteome states in the SV-treated Arabidopsis during disease progression. Proteomics analysis identified several upregulated proteins in the SV-infected plants (i.e., SV-treated plants carrying Botrytis infection). These upregulated proteins are involved in a plethora of biological functions, e.g., primary metabolism (i.e., glycolysis, tricarboxylic acid cycle, ATP synthesis, cysteine metabolism, and photosynthesis), redox homeostasis, and defense response. Additionally, our enzyme assays confirmed the enhanced activity of antioxidant enzymes in the SV-infected plants compared to control plants. Broadly, our results suggest that SV pre-treatment evokes a more efficient defense response in the SV-infected plants by modulating the primary metabolism and reactive oxygen species scavenging activity.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2011년도 제40회 동계학술대회 초록집
• /
• pp.423-423
• /
• 2011

Zinc oxide is metal oxide semiconductor with the 3.37 eV bandgap energy. Zinc oxide is very attractive materials for many application fields. Zinc Oxide has many advantages such as high conductivity and good transmittance in visible region. Also it is cheaper than other semiconductor materials such as indium tin oxide (ITO). Therefore, ZnO is alternative material for ITO. ZnO is attracting attention for its application to transparent conductive oxide (TCO) films, surface acoustic wave (SAW), films bulk acoustic resonator (FBAR), piezoelectric materials, gas-sensing, solar cells and photocatalyst. In this study, we synthesized ZnO nanoparticles and defined their physical and chemical properties. Also we studied about the application of ZnO nanoparticles as a photocatalyst and try to find a enhancement photocatalytic activity of ZnO nanorticles.. We synthesized ZnO nanoparticles using spray-pyrolysis method and defined the physical and optical properties of ZnO nanoparticles in experiment I. When the ZnO are exposed to UV light, reduction and oxidation (REDOX) reaction will occur on the ZnO surface and generate O2- and OH radicals. These powerful oxidizing agents are proven to be effective in decomposition of the harmful organic materials and convert them into CO2 and H2O. Therefore, we investigated that the photocatalytic activity was increased through the surface modification of synthesized ZnO nanoparticles. In experiment II, we studied on the stability of ZnO nanoparticles in water. It is well known that ZnO is unstable in water in comparison with TiO2. Zn(OH)2 was formed at the ZnO surface and ZnO become inactive as a photocatalyst when ZnO is present in the solution. Therefore, we prepared synthesized ZnO nanoparticles that were immersed in the water and dried in the oven. After that, we measured photocatalytic activities of prepared samples and find the cause of their photocatalytic activity changes.