• Toxicological Research
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• v.23 no.3
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• pp.263-269
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• 2007

Although taurine (2-aminoethanesulfonic acid) can inhibit oxidative stress in both animal and epidemiological studies, it is obscure whether taurine directly scavenges oxy-radicals or indirectly regulates oxidant production and/or antioxidant defense system. The reason for this discrepancy remains unknown but may be due, in part, to the lack of a validated assay system for evaluating oxy-radical scavenging capacity. The antioxidant activities of taurine and hypotaurine (2-aminoethanesulfinic acid), a precursor of taurine, against peroxyl radicals, hydroxyl radicals and peroxynitrites were determined by the total oxy-radical scavenging capacity (TOSC) assay and cell-based assay using H4IIE cells. tert-Butylhydroperoxide or hydrogen peroxide-induced cell toxicity determined by MTT assay was markedly inhibited by 10mM taurine or hypotaurine. The tert-butylhydroperoxide- or hydrogen peroxide-induced changes in oxidative stress markers, such as cellular glutathione and malondialdehyde, were ameliorated by 10mM taurine or hypotaurine. However, specific TOSC values calculated from the slope of the linear regression for taurine against peroxyl radicals, hydroxyl radicals or peroxynitrites were all less than 1 TOSC/mM. On the other hand specific TOSC values for hypotaurine against peroxyl radicals, hydroxyl radicals or peroxynitrites were 48, 2096, or 69 TOSC/mM, respectively. These results suggest that taurine protects cells against oxidative insults, which is not ascribed to directly scavenging activity of taurine against oxy-radicals. These results support the idea that the oxidation state of sulfur in antioxidants may be a determinant of oxy-radical scavenging capacity.

• Electronic Materials Letters
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• v.14 no.6
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• pp.678-688
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• 2018

The repeated-bending properties of Sn-0.7Cu, Sn-0.3Ag-0.7Cu (SAC0307), and Sn-3.0Ag-0.5Cu (SAC305) solders mounted on flexible substrates were studied using highly accelerated stress testing (HAST), followed by repeated-bending testing. In the Sn-0.7Cu joints, the $Cu_6Sn_5$ intermetallic compound (IMC) coarsened as the HAST time increased. For the SAC0307 and SAC305 joints, the $Ag_3Sn$ and $Cu_6Sn_5$ IMCs coarsened mainly along the grain boundary as the HAST time increased. The Sn-0.7Cu solder had a high contact angle, compared to the SAC0307 and SAC305 solders; consequently, the SAC0307 and SAC305 solder joints displayed smoother fillet shapes than the Sn-0.7Cu solder joint. The repeated-bending for the Sn-0.7Cu solder produced the crack initiated from the interface between the Cu lead wire and the solder, and that for the SAC solders indicated the cracks initiated at the surface, but away from the interface between the Cu lead wire and the solder. Furthermore, the oxide layer was thickest for Sn-0.7Cu and thinnest for SAC305, regardless of the HAST time. For the SAC solders, the crack initiation rate increased as the oxide layer thickened and roughened. $Cu_6Sn_5$ precipitated and grew along the grain and subgrain boundaries as the HAST time increased, embrittling the grain boundary at the crack propagation site.

• Journal of Animal Science and Technology
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• v.63 no.4
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• pp.766-777
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• 2021

Bezafibrate, a fibrate drug used as a lipid-lowering agent to treat hyperlipidemia, is a pan-agonist of peroxisome proliferator-activated receptor alpha. It can enhance mitochondrial fatty acid oxidation, oxidative phosphorylation, and mitochondrial biogenesis. After ovulation, oocytes may get arrested at the metaphase II (MII) stage until fertilization beyond optimal timing, which is termed as post-ovulatory aging. Post-ovulatory aging is a disease that degrades DNA, mitochondria, and oxidative system, and has a negative impact on embryo development and quality; however, the impact of bezafibrate during post-ovulatory aging has not been fully defined. In the present study, we assessed the ability of bezafibrate to prevent the progression of aging in in vitro conditions as well as the underlying mechanisms in pigs. An appropriate concentration of this drug (50 µM) was added, and then oxidative stress, reactive oxygen species downstream, mitochondrial biogenesis, and mitochondrial function were analyzed via immunofluorescence staining and real-time polymerase chain reaction. Bezafibrate significantly alleviated reactive oxygen species and ameliorated glutathione production simultaneously in oocytes and embryos. Moreover, it diminished H2A.X and attenuated CASPASE 3 expression produced by oxidative stress in oocytes and embryos. Furthermore, bezafibrate remarkably improved the mitochondrial function and blastocyst quality as well as markedly reduced the mitochondria/TOM20 ratio and mtDNA copy number. The elevated PARKIN level indicated that mitophagy was induced by bezafibrate treatment after post-ovulatory aging. Collectively, these results suggest that bezafibrate beneficially affects against porcine post-ovulatory oocyte aging in porcine by its antioxidant property and mitochondrial protection.

• The Korea Journal of Herbology
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• v.24 no.2
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• pp.67-76
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• 2009

Objectives : The present study compared Aralia continentalis Root and Angelica pubescens Root used in Korea and China respectively concerning their anti-oxidant effect Methods : We tested the anti-oxidant effect through in vitro experiment and in vivo experiment that induced oxidative stress using ethanol. Results : 1. DPPH scavenging activity was stronger in Aralia continentalis Root than in Angelica pubescens Root 2. Superoxide anion radical scavenging activity was similar between Aralia continentalis Root and Angelica pubescens Root 3. The linoleic acid peroxidation inhibition effect was stronger in Aralia continentalis Root than in Angelica pubescens Root. 4. The phenolic component was higher in Aralia continentalis Root than in Angelica pubescens Root. 5. Both Aralia continentalis Root and Angelica pubescens Root increased the concentration of GSH and decreased SOD activity in mice, in which oxidative stress was induced, and the effect was stronger in Aralia continentalis Root. 6. Aralia continentalis Root increased GSH peroxidase activity but Angelica pubescens Root did not have such an effect. 7. Neither Aralia continentalis Root nor Angelica pubescens Root had a significant effect on catalase, ADH and ALDH in mice, in which oxidative stress was induced. Conclusions : Aralia continentalis Root has a stronger anti-oxidant effect than Angelica pubescens Root. Thus, although Aralia continentalis Root is not an original plant recorded in botanical literature, it may be usable based on the data about its effects.

• Journal of Pharmacopuncture
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• v.27 no.2
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• pp.131-141
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• 2024

Objectives: Polycystic ovary syndrome (PCOS) is one of the most common disorders and it shows up to 20% prevalence in reproductive-aged women populations, but no cures are available to date. We aimed to investigate the protective effects of Changbudodam-tang (CBD) on cell death signaling pathways, inflammation, and oxidative stress observed in Bone-Marrow derived human mesenchymal stem cell (BM-hMSC) by means of PCOS therapeutics in the future. Methods: BM-hMSCs were applied with cell deaths and injuries. Apoptosis and pyroptosis signals were quenched with their related signaling pathways using quantitative PCR, Western blot, and fluorescence image analysis. Results: Our data clearly displayed hydrogen peroxide- and nigericin-treated cell death signaling pathways via regulations of mitochondrial integrity and interleukin (IL)-1β at the cellular levels (p < 0.01 or 0.001). We further observed that pre-treatment with CBD showed protective effects against oxidative stress by enhancement of antioxidant components at the cellular level, with respect to both protein and mRNA expression levels (p < 0.05, 0.01 or 0.001). The mechanisms of CBD were examined by Western blot analysis, and it showed anti-cell death, anti-inflammatory, and antioxidant effects via normalizations of the Jun N-terminal kinase/mitogen-activated protein kinase kinase 7/c-Jun signaling pathways. Conclusion: This study confirmed the pharmacological properties of CBD by regulation of cellular oxidation and the inflammation-provoked cell death condition of BM-hMSCs, which is mediated by the MKK7/JNK/c-Jun signaling pathway.

• Journal of Ginseng Research
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• v.21 no.3
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• pp.153-159
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• 1997

Living organisms have antioxidant enzymes, such as superoxide dismutase, catalase SE glutathione peroxidase, that protect themselves from the toxic effect of superoxide free radicals. Some report says that intracellular oxidation stress is involved in pathogenesis of chronic complications of diabetes mellitus. This study was performed to evaluate the effect of red ginseng on lipid peroxidation of red blood cell and antioxidant SOD activity of serum in NIDDM patients. As a result, there were trends for decrease of lipid peroxidases of RBC and Increase of SOD activity of serum in ginseng group but that were not statistically significant. Therefore, we suggest long term and large sized control study is necessary to confirm the protective effects of red ginseng on oxidative damage in NIDDM patients.

• Tribology and Lubricants
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• v.6 no.1
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• pp.116-125
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• 1990

An experimental programme was established to determine the wear behaviour of TiN coatings of thickness 1 $\mu$m and 3 $\mu$m. by PECVD with the variation of applied load, sliding velocity and sliding distance. It was shown that oxidation of transferred metal as sliding speed increased formed oxide film so that it contributed in decreasing the wear rate. With the roller-on-disc tribometer employed, the wear rate of the roller specimen was decreased with the increase in sliding distance due to the reduction in effective contact pressure. Finally, the severe cracks concentrated at the trailing edge of contact surface were explained in terms of high tensile stress prevailing at the trailing edge of the contact and were identified as a dominant wear mechanism as well as the strong local welding between coating layer and the counter surface, leading to the debonding of the coating layer.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.19.1-19.1
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• 2009

Open-cell Ni-Cr and Ni-Cr-Al(with gamma/gamma prime microstructure typical of Bi-base super alloys) foams are manufactured by pack-cementation at $1000{\boxplus}$degrees C, followed by homogenization at $1200{\boxplus}C$. The resulting alloyed foams retain the low relative densities (less than 3.5 wt.%). The oxidation behavior of Ni-Cr foams turns out to be identical to that of bulk Ni-Cr alloys, after taking into account the foam's higher surface area. The room-temperature compressive behavior of the Ni-Cr and Ni-Cr-Al is compared to model predictions. Additionally, the foam creep behavior, measured between 680 and $825{\boxplus}C$ in the stress range of 0.1-0.3 MPa, compared to two analytical models, namely strut compression and strut bending as high-temperature deformation modes.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05d
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• pp.45-48
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• 2003

BiSrCaCuO thin films were fabricated by atomic layer-by-layer deposition using an ion beam sputtering method. 10 wt% and 90 wt% ozone mixed with oxygen were used with ultraviolet light irradiation to assist oxidation. At early stages of the atomic layer by layer deposition, two dimensional epitaxial growth which covers the substrate surface would be suppressed by the stress and strain caused by the lattice misfit, then three dimensional growth takes place. Since Cu element is the most difficult to oxidize, only Sr and Bi react with each other predominantly, and forms a buffer layer on the substrate in an amorphous-like structure, which is changed to $SrBi_2O_4$ by in-situ anneal.

• BMB Reports
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• v.32 no.5
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• pp.440-444
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• 1999

Membrane lipid peroxidation processes yield reactive aldehydes that may react with copper,zinc superoxide dismutase (Cu,Zn SOD), one of the key antioxidant enzymes against oxidative stress. We investigated this possibility and found that exposing Cu,Zn SOD to malondialdehyde (MDA) or 4-hydroxynonenal (HNE) caused the loss of dismutase activity, cross-linking of peptides, and an increase in protein oxidation, reflected by the increased level of carbonyl groups. When Cu,Zn SOD that had been exposed to MDA or HNE was subsequently analyzed by amino acid analysis, histidine content was found to be significantly lost. Both MDA-and HNE-treated Cu,Zn SOD were resistant to proteolysis, which may imply that damaged proteins exist in vivo for a longer period of time than the native enzyme. The lipid peroxidation-mediated damage to Cu,Zn SOD may result in the perturbation of cellular antioxidant defense mechanisms, and subsequently lead to a pro-oxidant condition.