• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.786-789
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• 1997

Ti-6Al-4V has been used widely in biomedical field. But because of its toxicity, the ${\beta}$ stabilizing element, V, in Ti-6Al-4V has been replaced by Nb, Ta. Ti-10Ta-10Nb has been developed for biomedical applications. The fatigue crack propagation behavior of Ti-alloy(Ti-10Ta-10Nb) was investigated, in comparison with that of pure Ti. In order to better understand the fundamental fatigue behavior of Ti-10Ta-10Nb, rotating bending fatigue tests have been carried out. Ti-10Ta-10Nb has a better fatigue strength than pure Ti. In this paper, fatigue life has been predicted with Nisitani's equation of the fatigue crack propagation that can be established by measuring fatigue crack growth rates.

• Korean Journal of Clinical Laboratory Science
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• v.49 no.1
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• pp.8-14
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• 2017

To examine the protective effect of rosmarinic acid on the aluminum of dementia inducer, cultured C6 glioma cells were treated with various concentrations of aluminum chloride ($AlCl_3$) or rosmarinic acid. The cell viability, electron donating ability (EDA), superoxide dismutase (SOD)-like activity, and inhibitory activity of lipid peroxidation were evaluated for the antioxidant effect of rosmarinic acid. In these cultures, $AlCl_3$ sowed a cytotoxic effect by decreasing the cell viability in a dose-dependent manner; then, the $XTT_{50}$ value was measured at $142.2{\mu}M$ of $AlCl_3$ after treating the cultured C6 glioma cells with media containing $120{\sim}160{\mu}M\;AlCl_3$. Therefore, its toxicity was determined as mid-cytotoxic by Borenfreund and Puerner's toxic criteria; while, vitamin E of antioxidant markedly increased the cell viability on $AlCl_3$-induced cytotoxicity in these cultures. This study showed the antioxidant effect of rosmarinic acid via several assays, such as electron donating activity (EDA), superoxide dismutase (SOD)-like activity, and inhibitory activity of lipid peroxidation. From these findings, it is suggested that the oxidative stress is involved in $AlCl_3$-induced cytotoxicity, and rosmarinic acid was effective in the protection of $AlCl_3$-induced cytotoxicity by antioxidant activity. In conclusion, natural resources, like rosmarinic acid, may be a putative antioxidant agent for the treatment of reactive oxygen species (ROS)-mediated disease, such as dementia.

• Korean Journal of Metals and Materials
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• v.50 no.1
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• pp.86-91
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• 2012

Ti-6Al-4V extra low interstitial (ELI) alloy has been widely used as an orthopedic implant material because of its excellent biocompatibility, corrosion resistance and mechanical properties. However, V-free titanium alloys such as Ti-6%Al-7%Nb and Ti-5%Al-2.5%Fe have recently been developed because of the toxicity of V. Hydroxyapatite (HA) is used as a coating material on Ti or Ti biomaterials due to its good biocompatibility. However, HA coated on Ti alloy causes a problem for tissue by peeling off during usage. Therefore, such peeling off during long time usage can be suppressed by adding HA in Ti or Ti alloy composites. The aim of this study was to manufacture an ultra fine grained (UFG) Ti-Nb-HA bulk alloy, which is usually difficult to fabricate using melting and casting technology, by rapid sintering process using high energy mechanical milled (HEMM) powder.

• Entomological Research
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• v.48 no.5
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• pp.362-371
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• 2018

Chemical insecticides released into the environment may have adverse biological effects. Therefore, there is a need for ecofriendly insecticides for mosquito control. Xerophytic plant extracts that may provide more ecofriendly active component were evaluated against Culex pipiens 4th instars. Plant extracts prepared using different solvents with a Soxhlet apparatus and different concentrations were tested against Culex pipiens larvae. The effects were observed at 24 h and 72 h intervals and $LD_{50}$ and $LD_{90}$ values determined. Chloroform ($CHCl_3$) and ethyl acetate (EtOAc) extracts of Althaea ludwigii were the most effective against Cx. pipiens $4^{th}$ instars, but were highly dependent on extract concentrations and exposure time. Results suggest that A. ludwigii extracts contain bioactive compounds, such as phenols and saponins, that may provide effective Cx. pipienslarval control. However, the extract was found to be toxic to zebrafish larvae, and may be toxic to other aquatic fauna. Further studies to determine the active components and toxicity to other fauna are needed.

• Journal of environmental and Sanitary engineering
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• v.15 no.3
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• pp.88-93
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• 2000

The objective of this study was to depict the kinetic behavior of the platinum catalyst for the deep oxidation of VOCs and their mixture. The oxidation characteristics of VOCs, which were benzene, toluene, and styrene, was studies on a 0.5% $Pt/{\gamma}-Al_2O_3$ catalyst. The reactivity increases in order benzene>toluene>styrene. In mixtures, remarkable effects on reaction rate and selectivity have been evident ; the strongest inhibiting effect was shown by styrene and increases in a reverse order with respect to that of reactivity. The reaction model reveals that there is a competition between the two reactants for the oxidized catalyst. Thus, the nontoxic catalytic oxidation process was suggested as the new VOCs control technology.

• BMB Reports
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• v.36 no.6
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• pp.593-596
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• 2003

The effects of $N{\omega}$-nitro-L-arginine methylester (L-NAME) and L-arginine on cardiotoxicity that is induced by doxorubicin (Dox) were investigated. A single dose of Dox 15 mg/kg i.p. induced cardiotoxicity, manifested biochemically by a significant elevation of serum creatine phosphokinase (CPK) activity [EC 2.7.3.2]. Moreover, cardiotoxicity was further confirmed by a significant increase in lipid peroxides, measured as malon-di-aldehyde (MDA) in cardiac tissue homogenates. The administration of L-NAME 4 mg/kg/d p.o. in drinking water 5 days before and 3 days after the Dox injection significantly ameliorated the cardiotoxic effects of Dox, judged by the improvement in both serum CPK activity and lipid peroxides in the cardiac tissue homogenates. On the other hand, the administration of L-arginine 70 mg/kg/d p.o. did not protect the cardiac tissues against the toxicity that was induced by the Dox treatment. The findings of this study suggest that L-NAME can attenuate the cardiac dysfunction that is produced by the Dox treatment via the mechanism(s), which may involve the inhibition of the nitric oxide (NO) formation. L-NAME may, therefore, be a beneficial remedy for cardiotoxicity that is induced by Dox and can then be used to improve the therapeutic index of Dox.

• Nutrition Research and Practice
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• v.12 no.6
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• pp.535-540
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• 2018

BACKGROUND/OBJECTIVES: Propolis has a rich source of bioactive compounds and has renal and hepatic protective properties. The purpose of this study was to investigate the beneficial effect of hydro-ethanolic extract of propolis against paracetamol-induced liver damage and impairment of kidney function, as well as hematological changes in rats. MATERIALS/METHODS: Six groups of rats were used; the first group was served as a control; the second and third groups were treated by propolis extract at a dose of 50 and 100 mg/kg.B.WT. respectively; the fourth group was treated by paracetamol (200 mg/kg.B.WT.); the fifth group was treated by propolis (50 mg/kg.B.WT.) for eight days and then received similar dose of propolis for following seven days with paracetamol at a dose of 200 mg/kg.B.WT. daily for the seven days; and the sixth group was treated with propolis (100 mg/kg.B.WT.) for eight days and then received similar dose of propolis for following seven days with paracetamol at a dose of 200 mg/kg.B.WT. daily for the seven days. All the animals were treated for a period of 15 days. At the end of the experimental period, blood samples were collected for measurement of the liver enzymes, serum albumin, protein and creatinine, blood urea nitrogen, hematological parameters, and urine volume, protein and albumin. RESULTS: Paracetamol over dose significantly lowered hemoglobin, serum total protein, albumin, and uric acid, while it significantly increased blood creatinine, blood urea nitrogen, alanine aminotransferase, aspartate aminotransferase and lactate dehydrogenase activities, white blood cells, and platelet count as compared to the control. However, these alterations were significantly attenuated by the use of propolis extract and the effect was dose dependent. Interestingly, propolis prevented paracetamol induced proteinuria, low hemoglobin and body weight loss. CONCLUSIONS: Propolis significantly prevented paracetamol induced renal, hepatic and hematological toxicity and might be useful in the management of liver and renal diseases particularly proteinuria.

• Korean Journal of Veterinary Research
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• v.46 no.3
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• pp.225-234
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• 2006

In the present study toxicity and immunostimulating activity of the lectin(KML-C), which was extracted from Korean mistletoe(Viscum album coloratum) were investigated in swine. To determine the toxicity, lectin was injected into thigh or cervical muscles of 4-week-old piglets(Landrace) and observed clinically and pathologically. For determination of the immnunostimulating activity, lectin($0.7{\mu}g/kg$ of body weight)-adjuvanted vaccine of Aujeszky's disease virus(ADV)(NYJ1-87) which was inactivated by 0.2% formalin was injected into the cervical muscle of antibody-negative piglets in the same age group. Subpopulation of the immune cells and serum neutralizing(SN) antibodies in the piglets were examined after vaccination, and resistance of the piglets against challenge by virulent NYJ1-87 was further examined. The results were also compared with those from piglets injected with aluminum hydroxide [$Al(OH)_3$]-adjuvanted vaccine of inactivated NYJ1-87 and NYJ1-87 vaccine without adjuvant, and the results are as follows. By injection of lectin with $30{\mu}g/kg$ of body weight to the thigh muscle, all of 12 piglets died after signs such as dyspnea, fever, systemic erythema and subcutaneous hemorrhages, and lesions pertaining to poisonous hepatitis and dysfunction of kidney were observed. By injection of lectin with $7{\mu}g/kg$ of body weight to the thigh muscle, all of 12 piglets showed signs such as edema and cutaneous hemorrhage in the injected area, lameness and depression, and lesions pertaining to poisonous hepatitis and dysfunction of kidney were observed. By injection of lectin with 1, 3 and $5{\mu}g/kg$ of body weight to the thigh muscle of each one piglet, signs such as congestion, induration and grayish coloration in the injected area, depression and inappetence were observed in all piglets. Toxic changes were also observed in the liver and kidney of piglets by lectin of 3 and $5{\mu}g$. By injection of lectin with 0.5 and $0.7{\mu}g/kg$ of body weight to the cervical muscle of each 9 piglets, all piglets were clinically normal and there were no significant changes in blood counts and chemistry values. Whereas, epithelial swelling and vacuolation of convoluted tubules were observed from one piglet injected with lectin of $0.7{\mu}g$, and necrosis and fibrosis of muscular fiber were observed in the muscle of one piglet injected with lectin of $0.5{\mu}g$. Only population of sIgM+ B lymphocytes increased among immune cells in all of 15 piglets immunized with lectin($0.7{\mu}g/kg$ of body weight)-adjuvanted vaccine, while compared to those in $Al(OH)_3$-adjuvanted vaccine and vaccine without adjuvant. No additional stimulation to the immune cells was recognized when lectin was added to $Al(OH)_3$-adjuvanted vaccine. In piglets immunized with lectin-adjuvanted vaccine, SN titers in reciprocal values for loge were 1.3-4.0 at 1-4 weeks after vaccination, which was similar to those with 1.0-3.3 by vaccine without adjuvant but lower than those with 2.0-5.7 by $Al(OH)_3$-adjuvanted vaccine. Also, no additional increase in the SN titers was recognized when lectin was added to $Al(OH)_3$-adjuvanted vaccine. Piglets immunized with lectin-adjuvanted vaccine were resistant to challenge by the virulent NYJ1-87 at 4 weeks after vaccination, and the SN titers reached to 5.0 one week after challenge, which was higher than those with 4.0 by vaccine without adjuvant but somewhat lower than those with 7.7 by $Al(OH)_3$-adjuvanted vaccine.

• Ecology and Resilient Infrastructure
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• v.8 no.3
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• pp.135-142
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• 2021

Biopolymers have been known as eco-friendly soil strengthening materials and studied to apply levees. However, the effect of biopolymer on vegetation is not fully understood. In this study, we analyzed the root growth of Camelina sativa L. (Camelina) when the xanthan gum was amended to soil in Aluminum (Al) stress conditions. Amendment of 0.05% xanthan gum increased root growth of Camelina under Al stress conditions. Under the Al stress condition, expression of aluminum activate malate transporter 1 (ALMT1) gene of Camelina root was induced but showed a lower level of expression in xanthan gum amended soil than non-amended soil. Additionally, the binding capacity of xanthan gum with Al ions in the solution was confirmed. Using morin staining and ICP-OES analysis, the Al content of the roots in the xanthan gum soil was lower than in the non-xanthan gum soil. These results suggest that xanthan gum amended soils may reduce the detrimental effects of Al on the roots and positively affect the growth of plants. Therefore, xanthan gum is not only an eco-friendly construction material but also can protect the roots in the disadvantageous environment of the plant.

• The Korean Journal of Ecology
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• v.17 no.3
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• pp.287-297
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• 1994

To elucidate the cause of growth decline of pitch pine (Pinus rigida) in Seoul, tree density, tree age and physico-chemical properties of soils were investigated at 33 sites of pitch pine forests in metropolitan Seoul, its vicinity and rural areas. The physical properties of soils except for soil texture in Seoul did not differ from those in rural areas. pH values, base saturation, and Ca and Mg contents of soils in Seoul, however, were significantly lower than those in suburbs and rural areas. In contrast, soluble Al and $S0_4^{2-}-S$ contents in Seoul were higher than those in rural areas. Low pH of forest soils in Seoul and suburbs seems to be caused by acid deposition. According to multiple regression analysis, growth of pitch pine in Seoul was affected by several factors in the following order: soil bulk density < Al content of soils < tree density < Mg contents of soil < tree age. We concluded that the acidification of forest soil can be a predisposing factor for the growth decline of pitch pine in metropolitan areas.