• Korea Journal of Cosmetic Science
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• 제1권1호
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• pp.1-9
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• 2019

The identification of compounds with anti-senescence activity in cell culture system is a first step in aging research. Given that pyruvate can be used energy source by conversion to acetyl-CoA in mitochondria, and protects cultured cell from various stress-induced cell damage and cell death, synthetic media (e.g., DMEM) often includes 1 mM pyruvate, which is very higher than the pyruvate concentration in human blood (approximately 30 ��M). However, the use of medium containing high concentration of pyruvate is not suitable for screening anti-senescence compounds, because pyruvate also protects against the cellular senescence of primary human dermal fibroblasts (NHDFs) through NAD+ generated during conversion to lactate. In this study, four extracts, i.e., Sprouted seed and fruit complex, Poncirus trifoliata fruit extract, Jaum balancing complex, and Prunus mume extract were used for evaluation of different anti-senescence effect in the absence or presence of 0.1 mM pyruvate, similar to the physiological pyruvate concentration. The senescence in NHDFs cultured with DMEM in the presence of 0.1 mM pyruvate (approximately the physiological concentration in human blood) is accelerated, as observed in pyruvate deprivation conditions. The cytotoxicity of the Poncirus trifoliata fruit extract was protected by pyruvate, and Jaum balancing complex and Prunus mume extract had anti-senescence activity in the presence of 0.1 mM pyruvate, but not in the absence of pyruvate. Given that pyruvate is a powerful protector against both cytotoxicity and cellular senescence, the screening of candidate agents for anti-senescence in high pyruvate conditions using an in vitro cell culture system is not valid. Therefore, we recommend the use of a low concentration of pyruvate to evaluate the anti-senescence effects of candidates, which is more similar to in vivo aging conditions than excessive stress-induced senescence models, to exclude the effect of excessive pyruvate in vitro.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2011년 춘계학술대회논문집
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• pp.500-503
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• 2011

Blood flow simulations in an idealized carotid bifurcation model with considering wall compliance were carried out to investigate the effect of wall elasticity on the wall shear stress and wall solid stress. Canonical waveforms of flowrates and pressure in the carotid arteries were imposed for the boundary conditions. Comparing to rigid wall model, generally, we could find an increased recirculation region at the carotid bulb and an overall reduced wall shear stress. Also, there was appreciable change of flowrate and pressure waveform in longitudinal direction. Solid and wall shear stress concentration occurs at the bifurcation apex.

• 한국해양생명과학회지
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• 제6권1호
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• pp.31-37
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• 2021

Larvae from the marine medaka fish Oryzias javanicus were exposed with polystyrene microplastics (MPs) for 24 h. Exposure to waterborne fluorescent MPs showed clear ingestion and egestion in feces. Under constant MPs, the concentration of dissolved oxygen significantly decreased in 24 h compared to the control. Significant intracellular reactive oxygen species and malondialdehyde contents were detected in larvae, indicating oxidative stress and lipid peroxidation. Significant elevations in mRNA expressions of heat shock protein 70 and antioxidant defense system genes (glutathione reductase, glutathione peroxidase, catalase, and superoxide dismutase) were measured with increases in enzymatic activity of oxidative stress-related proteins. Taken together, the alterations to the molecular and biochemical components suggested that waterborne MPs had an oxidative stress effect on marine medaka larvae.

• Steel and Composite Structures
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• 제41권6호
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• pp.851-860
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• 2021

In this paper, a new approach of interface stress analysis in steel beam strengthened by porous FGM (Functionally Graded Materials) is presented to calculate the shear stress in the hybrid steel beam and loaded by a uniformly distributed load. The results show that there exists a high concentration of shear stress at the ends of the imperfect FGM, which might result in premature failure of the strengthening scheme at these locations. A parametric study has been conducted to investigate the sensitivity of interface behavior to parameters such as the rigidity of FGM plate (degree of homogeneity), the porosity index of FGM and the thickness of adhesive all were found to have a marked effect on the magnitude of maximum shear stress in the FGM member. we can conclude that the new approach is general in nature and may be applicable to all kinds of materials.

• 대한한의학방제학회지
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• 제23권1호
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• pp.111-119
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• 2015

Objectives : The purpose of this study was to investigate the antioxidant activity of water extract of Woogyuyeum (WGY) in Leydig cells. Methods : We investigated the cytoprotective effect of WGY in cultured mouse Leydig cells by MTT assay. Leydig cells treated with WGY were incubated in the presence or absence of 50 μM hydrogen peroxide at 37℃ for 24 h. The protective effects of WGY against hydrogen peroxide-induced oxidative stress, lipid peroxide (LPO), superoxide dismutase (SOD), and catalase activity assays were performed in Leydig cells. Results : As a result, WGY showed no significant cytotoxicity in Leygdig cells. WGY showed cell viability as 103.65% in 5 μg/ml concentrations. The cytotoxicity induced by hydrogen peroxide in Leygdig cells, the antioxidant effects of WGY was increased in 1, 5, 50, 100 ug/ml concentraions. 100 μg/ml concentration of WGY showed maximum antioxidant effects. Treatment of cells with 100 μg/ml WGY significantly reduced the MDA concentration to 0.23 nmoles/mg protein. SOD activity was increased at 1, 100 μg/ml concentration of WGY and catalase activity was significantly increased at 50, 100 μg/ml concentrations of WGY, respectively. Conclusions : In conclusion, WGY has antioxidant activities against hydrogen peroxide-induced oxidative stress in Leydig cells.

• The Korean Journal of Physiology and Pharmacology
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• 제10권4호
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• pp.207-212
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• 2006

Mitochondrial permeability transition has been shown to be involved in neuronal cell death. Mitochondrial monoamine oxidase (MAO)-B is considered to play a part in the progress of nigrostriatal cell death. The present study examined the effect of MAO inhibitors against the toxicity of 1-methyl-4-phenylpyridinium $(MPP^+)$ in relation to the mitochondrial permeability transition. Chlorgyline (a selective inhibitor of MAO-A), deprenyl (a selective inhibitor of MAO-B) and tranylcypromine (nonselective inhibitor of MAO) all prevented cell viability loss, cytochrome c release, caspase-3 activation, formation of reactive oxygen species and depletion of GSH in differentiated PC12 cells treated with $500\;{\mu}M$$MPP^+$. The MAO inhibitors at $10\;{\mu}M$ revealed a maximal inhibitory effect and beyond this concentration the inhibitory effect declined. On the basis of concentration, the inhibitory potency was tranylcypromine, deprenyl and chlorgyline order. The results suggest that chlorgyline, deprenyl and tranylcypromine attenuate the toxicity of $MPP^+$ against PC12 cells by suppressing the mitochondrial permeability transition that seems to be mediated by oxidative stress.

• 생명과학회지
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• 제9권5호
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• pp.596-603
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• 1999

The effects of anti-stress mind tonic (ASMT) drink (ASMT-0.1% and ASMT-0.5% concentration) were tested for the anti-stress action. ICR male mice (20$\pm$2 g) were fed with basic experimental diets free access to water containing these ingredients for 18 days. Psychological stress/sociopsychological stress were exposed by foot-shock for 1 hour for 3 days. Both ASMT-0.1 and ASMT-0.5 groups in the sociopsychological stress resulted in a significant decrease of 19.1% and 41.9% in plasma corticosterone (CS) secretion compared with psychological stress (control group). Noradrenaline (NA) secretions in the brain were significantly increased 23.4% and 35.9%, respectively, in ASMT-0.1 and ASMT-0.5 groups compared with control group. MHPG-SO4 (3-Methoxy-4-hydroxyphenylethyleneglycol sulfate) levels in the brain resulted in a marked decreases of 27.1% and 19.6%, respectively in ASMT-0.1 and ASMT-0.5 groups. NA/MHPG-SO4 ratios in the brain of ASMT-0.1 and ASMT-0.5 groups resulted in a significantly increase of about 70% compared with control group. These suggest that mind tonic anti-stress drink can effectively ridded the sociopsychological stress.

• 한국초지조사료학회지
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• 제10권2호
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• pp.70-76
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• 1990

The present study elucidates the effect of drught by polyethylene glycol solution on germination of five temperate and two tropical grasses. The results obtained can be summarized as follows: 1. The germination percentage of seven grasses decreased with increasing concentration of polythylene glycol. 2. The germination pattern hi higher concentration of polyethylene glycol showed similar trends to the emergence pattern under drought stress in soil condition. 3. The treatment of 30g is most useful at this study. Therefore, polythlene glycol was the appropriate to creat the drought condition of soil.

• Journal of Microbiology and Biotechnology
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• 제18권4호
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• pp.718-724
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• 2008

Dissolved oxygen (DO) and shear stress have pronounced effects on hyaluronic acid (HA) production, yet various views persist about their effects on the molecular weight of HA. Accordingly, this study investigated the effects of DO and shear stress during HA fermentation. The results showed that both cell growth and HA synthesis were suppressed under anaerobic conditions, and the HA molecular mass was only $(1.22{\pm}0.02){\times}10^6 Da$. Under aerobic conditions, although the DO level produced no change in the biomass or HA yield, a high DO level favored the HA molecular mass, which reached a maximum value of $(2.19{\pm}0.05){\times}10^6 Da$ at 50% DO. Furthermore, a high shear stress delayed the rate of HA synthesis and decreased the HA molecular weight, yet had no clear effect on the HA yield. Therefore, a high DO concentration and mild shear environment would appear to be essential to enhance the HA molecular weight.

• 한국미생물·생명공학회지
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• 제28권1호
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• pp.52-58
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• 2000

The effect of fivrinolytic enzyme produced from Bacillus subtilis K-54 on the thrombosis and stress in vivo was investigated. Each partially purified fibrinolytic enzyme of 4 protein casein unit was administered orally for 3 days before intravenously injection with collagen and epinephrine. In the mice group administered with the enzyme and increased life span of mice was observed in comparison with that of control. The result suggest that the enzyme may prevent the formation of thrombos in vivo. Administration of the enzyme did not influence to stress itself because 5-hydroxyindoleacetatic acid concentration of brain in the mice group with stress did not decreased after the administration of the enzyme. The value of lipid peroxide (LPO) of the liver and brain cells in the group treted with the enzyme was lower than that of control. However, protein degradation (PDP value showed no significant difference between treatment and control groups. In addition, the value of activated partial thromboplastin time (APTT), protrombin time (PT0 and antiplasmin in blood were higher in the stress group than that of the enzyme treated group.