• IMMUNE NETWORK
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• 제14권5호
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• pp.241-248
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• 2014

It is debatable whether AMP-activated protein kinase (AMPK) activation is involved in anti-apoptotic or pro-apoptotic signaling. AICAR treatment increases AMPK-${\alpha}1$ phosphorylation, decreases intracellular reactive oxygen species (ROS) levels, and significantly increases Annexin V-positive cells, DNA laddering, and caspase activity in human myeloid cell. AMPK activation is therefore implicated in apoptosis. However, AMPK-${\alpha}1$-knockdown THP-1 cells are more sensitive to apoptosis than control THP-1 cells are, suggesting that the apoptosis is AMPK-independent. Low doses of AICAR induce cell proliferation, whereas high doses of AICAR suppress cell proliferation. Moreover, these effects are significantly correlated with the downregulation of intracellular ROS, strongly suggesting that AICAR-induced apoptosis is critically associated with the inhibition of NADPH oxidase by AICAR. Collectively, our results demonstrate that in AICAR-induced apoptosis, intracellular ROS levels are far more relevant than AMPK activation.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.551-554
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• 2006

Inhibition of propellant temperature rising in liquid propulsion rocket using cryogenic fluid as a propellant is very important. Especially propellant temperature rising during stand-by after filling and pre-pressurization can bring into cavitation in turbo-pump. One of the method preventing propellant temperature rising in cryogenic feeding system is recirculating propellant through the loop composed of propellant tank, feed pipe, and recirculation pipe. The circulation of propellant is promoted through gas-lift effect by gas injection to lower position of recirculation pipe. In this experiment liquid oxygen and gas helium is used as propellant and injection gas. Under atmospheric and pressurized tank ullage condition, helium injection flow-rate is varied to observe the variation of recirculating flow-rate and propellant temperature in the feed pipe. There is appropriate helium injection flow-rate for gas-lift recirculation system.

• Journal of Yeungnam Medical Science
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• 제34권2호
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• pp.174-181
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• 2017

Ferroptosis is a newly recognized type of cell death that results from iron-dependent lipid peroxidation and is different from other types of cell death, such as apoptosis, necrosis, and autophagic cell death. This type of cell death is characterized by mitochondrial shrinkage with an increased mitochondrial membrane density and outer mitochondrial membrane rupture. Ferroptosis can be induced by a loss of activity of system $X_c{^-}$ and the inhibition of glutathione peroxidase 4, followed by the accumulation of lipid reactive oxygen species (ROS). In addition, inactivation of the mevalonate and transsulfuration pathways is involved in the induction of ferroptosis. Moreover, nicotinamide adenine dinucleotide phosphate oxidase and p53 promote ferroptosis by increasing ROS production, while heat shock protein beta-1 and nuclear factor erythroid 2-related factor 2 inhibit ferroptosis by reducing iron uptake. This article outlines the molecular mechanisms and signaling pathways of ferroptosis regulation, and explains the roles of ferroptosis in human disease.

• Corrosion Science and Technology
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• 제16권4호
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• pp.167-174
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• 2017

Bicarbonate/carbonate and molybdate anions have been characterized for their inhibitive effect on pitting corrosion of carbon steel in simulated concrete pore solution by using electrochemical tests such as electrochemical impedance (EIS) and linear polarization (LP). It was revealed that bicarbonate/carbonate has a weak inhibitive effect on pitting corrosion that is approximately one order of magnitude lower compared to hydroxide. Molybdate is effective against pitting corrosion induced by the concentration of chloride as low as 113 mM and can increase the pitting potential of a previously pitted sample to the oxygen evolution potential by the concentration of molybdate as much as 14.6 mM only. The formation of a $CaMoO_4$ film on the surface hinders the reduction of dissolved oxygen on the steel surface, reducing corrosion potential and increasing the safety margin between corrosion potential and pitting potential further. In addition, pore-plugging by $FeMoO_4$ as a type of salt film within pits increases the likelihood of repassivation.

• 한국자원식물학회지
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• 제27권6호
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• pp.714-719
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• 2014

This study investigated DNA damage protection and anti-inflammatory activity of different solvent fractions from Aruncus dioicus var. kamtschaticus (A. dioicus) aerial parts water extract. As for DNA damage protection, distilled water ($H_2O$) fraction displayed the most powerful protection for DNA damage at a concentration of 1 mg/ml. As for anti-inflammatory activity, dichloromethane ($CH_2Cl_2$) fraction exhibited the highest NO inhibition activity, ranging from 61% to 19% ($10-40{\mu}g/ml$). Furthermore, the levels of pro-inflammatory cytokines mRNA expressions and intracellular reactive oxygen species (ROS) were employed to verify the anti-inflammatory activity of the $CH_2Cl_2$ fraction on further researches. It could be concluded that A. dioicus had a significantly effect of DNA damage protection and anti-inflammatory activity which also as an essential edible vegetable and medicinal species.

• 한국식품과학회지
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• 제53권2호
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• pp.213-217
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• 2021

Benign prostate hyperplasia (BPH) is one of the most common elderly disease, and because of prolonged incubation period and many side effects of medication or surgical interventions, the use of dietary phytochemicals is considered as an effective measure for prevention of BPH. The purpose of this study is to investigate the mechanism of inhibition effect for BPH by flavonoids such as baicalein and kaempferol. BPH cells were collected through biopsy from patients with PSA of 4 or higher, followed by primary culture. In vitro experiments were conducted to evaluate mitochondrial respiration, intracellular reactive oxygen species (ROS) level and expression of inflammatory markers, genes, and anti-oxidants. In conclusion, baicalein and kaempferol have been demonstrated to inhibit BPH through lowering ROS, thereby reducing inflammation triggers, and reduced inflammation. This study is expected to be helpful in the development of flavonoids that have a clinical effect on suppressing BPH.

• Environmental Engineering Research
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• 제13권3호
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• pp.125-130
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• 2008

Free ammonia ($NH_3$-N) inhibition of nitrite-oxidizing bacteria (NOB) has been widely studied for partial nitrification (or nitrite accumulation) and denitrification via nitrite ($NO_2^-$-N) as a low-cost treatment of ammonium containing wastewater. The literature on $NH_3$-N inhibition of NOB, however, shows disagreement about the threshold $NH_3$-N concentration and its degree of inhibition. In order to clarify the confusion, a simple and cheap respirometric method was devised to investigate the effect of free ammonia inhibition of NOB. Sludge samples from an autotrophic nitrifying reactor were exposed to various $NH_3$-N concentrations to measure the maximum specific nitrite oxidation rate ($\hat{K}_{NO}$) using a respirometer. NOB biomass was estimated from the yield values in the literature. Free ammonia inhibition of nitrite oxidizing bacteria was reversible and the specific nitrite oxidation rate ($K_{NO}$) decreased from 0.141 to 0.116, 0.100, 0.097 and 0.081 mg $NO_2^-$-N/mg NOB h, respectively, as the $NH_3$-N concentration increased from 0.0 to 1.0, 4.1, 9.7 and 22.9 mg/L. A nonlinear regression based on the noncompetitive inhibition mode gave an estimate of the Inhibition concentration ($K_I$) of free ammonia to be 21.3 mg $NH_3$-N/L. Previous studies gave $\hat{K}_{NO}$ of Nitrobacter and Nitrospira as 0.120 and 0.032 mg/mg VSS h. The free ammonia concentration which inhibits Nitrobacter was $30{\sim}50\;mg$ $NH_3$-N/L and Nitrospira was inhibited at $0.04{\sim}0.08\;mg$ $NH_3$-N/L. The results support the fact that Nitrobacter is the dominant NOB in the reactor. The variations in the reported values of free ammonia inhibition may be due to the different species of nitrite oxidizers present in the reactors. The respirometric method provides rapid and reliable analysis of the behavior and community of the nitrite oxidizing bacteria.

• Preventive Nutrition and Food Science
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• 제10권1호
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• pp.46-51
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• 2005

The protective effect of Acanthopanax senticosus (AS) extract on alloxan-induced pancreatic β-cell damage was investigated in HIT T-15 cells, a Syrian hamster pancreatic β-cell line. Alloxan caused the pancreatic β-cell damage through the generation of reactive oxygen free radicals, increased DNA fragmentation, and decreased cellular NAD/sup +/ levels. The β-cell damage was significantly prevented by the pretreatment with water soluble extract of AS roots. These results suggest that the protective effect of AS extract, on alloxan-induced β-cell damage, is primarily due to the inhibition of the generation of reactive oxygen free radical species (ROS) by alloxan.

• BMB Reports
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• 제48권5호
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• pp.271-276
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• 2015

Baicalin is a flavonoid derived from the dried root of Scutellaria baicalensis. In this study, oxygen-induced retinopathy was used to characterize the anti-angiogenic properties of baicalin in mice. Pups were exposed to a hyperbaric oxygen environment to induce retinal angiogenesis and were subjected to intraperitoneal injection of baicalin. Avascular area, neovascular tufts, and neovascular lumens were quantified from digital images. Compared to the vehicle, baicalin clearly reduced the central avascular zone and the number of neovascular tufts and lumens. High-dose baicalin (10 mg/kg) significantly reduced the expression of matrix metalloproteinase-2 (MMP-2), MMP-9, angiotensin II, and vascular endothelial growth factor (VEGF). These results show that baicalin is a powerful antiangiogenic compound that attenuates new vessel formation in the retina after systemic administration, and is a candidate substance for therapeutic inhibition of retinal angiogenesis. [BMB Reports 2015; 48(5): 271-276]

• 동의생리병리학회지
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• 제28권4호
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• pp.379-383
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• 2014

The purpose of this study is to investigate the effects of silkworm extracts (SWE) on reactive oxygen species formation in mice (C57BL/6). Mice were administrated intraperitoneally with SWE (20 mg/kg/day) for 14 days. All animals were sacrificed 24 hours after the last SWE treatment and then extracted the blood and brain tissue in mouse. The researcher measured several parameters related to reactive oxygen species formation, malondialdehyde (MDA) and hydrogen peroxide ($H_2O_2$) contents in serum, whole brain, cerebral cortex and cerebellum. The results showed that MDA content of pre-SWE treatment was decreased significantly in serum, mitochondrial and cytosolic fraction of whole brain and cerebellum (P<0.01). The $H_2O_2$ content of pre-SWE treatment was decreased significantly in mitochondrial fraction of whole brain, cerebral cortex and cerebellum (P<0.01). These results suggest that SWE plays an important role for inhibition of oxidative damage of cells as well as antioxidant effect, aging delay and cells protected from irradiation.