• YAKHAK HOEJI
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• v.53 no.5
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• pp.286-292
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• 2009

In this study, we investigated the anti-obese activity of HPJ extract in C57BL/6J mice. The C57BL/6J mice were randomly divided into five groups: normal control group (Con), high fat diet control group (HFD), treatment groups with HPJ at 125 mg/kg (HPJ125), 250 mg/kg (HPJ250), or 500 mg/kg (HPJ500). To induce an obesity, mice were fed by a high fat diet for 6 weeks, and mice were administered with HPJ extract once a day for 8 weeks. At the end of treatment, we examined the effect of HPJ extract on body weight, plasma lipid, and lipogenic enzymes. HPJ extract was found to lower whole body and epididymal adipose tissue weights and lowered plasma levels of glucose, insulin, triglyceride (TG), total cholesterol (TC), non-esterified fatty acid (NEFA) and leptin, compared to those in HFD group. Histological analyses of the liver and fat tissues of mice treated with HPJ extract revealed significantly decreased number of lipid droplets and decreased size of adipocytes compared to the HFD group. In addition, HPJ extract preserved the morphological integrity of pancreatic islets. To elucidate an action mechanism of HPJ extract, Western blot and RT-PCR were performed using epididymal adipose tissues. HPJ extract up-regulated the levels of phosphorylated adenosine monophosphate-activated protein kinase (AMPK) and its substrate, acetyl-CoA carboxylasse (ACC). HPJ extract also attenuated lipogenic gene expressions of sterol regulatory element-binding protein $1{\alpha}$ (SREBP$1{\alpha}$), fatty acid synthase (FAS), sterol-CoA desaturase 1 (SCD1) and glycerol-3-phosphate acyltransferase (GPAT) in dose-dependent manners. In contrast, expressions of lipolytic genes such as peroxisome proliferator-activated receptor-$\alpha$ (PPAR-${\alpha}$) and CD36, and fatty acid $\beta$-oxidation gene, carnitine palmitoyltransferase-1 (CPT-1) were increased. These results suggest that HPJ extract ameliorates obesity through inhibiting synthesis of lipogenic enzymes as well as stimulating fatty acid oxidation resulting from activation of AMPK, and HPJ extract could be developed as a potential therapeutic agent for obese patients.

• Journal of Life Science
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• v.21 no.7
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• pp.932-938
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• 2011

Ginsenoside Rg1 is a pharmacologically active component isolated from ginseng. The goal of this study was to clarify the beneficial effects of Rg1 on glucose and lipid metabolism in diabetic animals (db/db mice). To accomplish this, ten week old db/db mice were administered 10 mg/kg of Rg1 for 15 days. Rg1 did not influence the weight of db/db mice when compared with vehicle-treated db/db mice. The administration of Rg1 lowered fasting plasma glucose, and improved glucose tolerance. Importantly, Rg1 markedly reduced both plasma triglyceride and free fatty acids, and increased high-density lipoprotein cholesterol (HDL-C) concentrations in db/db mice. Rg1 activated promoter activity of chimeric GAL4-PPAR${\alpha}$ reporter and increased expression of peroxisome proliferator-activated receptor alpha (PPAR${\alpha}$) target genes such as carnitine palmitoyltransferase-1 (CPT-1) and acyl-CoA oxidase (ACO), which are involved in fatty acid oxidation. These findings indicated that improvement of lipid profiles by Rg1 may be associated with increased fatty acid oxidation via PPAR${\alpha}$ activation. Taken together, these results suggest that Rg1 could have beneficial effects for controlling hyperglycemia and hyperlipidemia associated with type 2 diabetes.

• Korean Journal of Materials Research
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• v.8 no.6
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• pp.505-512
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• 1998

In this study, two-layer thermal barrier coatings composed of plasma sprayed 0.3mm $ZrO_2(8wt% Y_2o_3)$ ceramic coating layer and O.lmm $NiCrAlCoY_20_3$ bond coating layer on AISI 316 were investigated microstructure of the coating, oxidation of the metallic bond coating and adhesive strength to evaluate the durability of coating layer after cyclic and isothermal test at 90$0^{\circ}C$. And quantitative phase analysis of $ZrO_2(8wt% Y_2o_3)$ ceramic coating was performed as a function of thermal exposure time using XRD technique. The results showed that the amount of m - 2rO, phase in the coating was slightly increased with increasing thermal exposure time at 90$0^{\circ}C$. The c/a ratio of t' - $ZrO_2$ in the as-sprayed coating was 1.0099 and slightly increased to 1.0115 after 100 hours heat treatment. It was believed that $Y_2O_3$ in high yttria tetragonaJ(t') was transformed to low yttria tetragonaJ(t) by $Y_2O_3$ diffusion with increasing thermal exposure time. The adhesive strength was gradually decreased as thermal exposure time increased. After the isothermal test, the failure predominantly occured in ceramic coating layer. On the other hand. the specimens after cyclic thermal test were mostly failed at bond coating/ceramic coating interface. The failure was oeeured by decreasing the bond strength between bond coating and oxide scale which were formed by oxidation of the metallic elements within bond coating and by thermal stress due to thermal expansion mismatches between the oxide scale and ceramic coating.

• Journal of Korean Dental Science
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• v.11 no.2
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• pp.71-81
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• 2018

Purpose: The purpose of this study was to investigate the corrosion behaviors of dental implant alloy after microsized surface modification in electrolytes containing Mn ion. Materials and Methods: $Mn-TiO_2$ coatings were prepared on the Ti-6Al-4V alloy for dental implants using a plasma electrolytic oxidation (PEO) method carried out in electrolytes containing different concentrations of Mn, namely, 0%, 5%, and 20%. Potentiodynamic method was employed to examine the corrosion behaviors, and the alternatingcurrent (AC) impedance behaviors were examined in 0.9% NaCl solution at $36.5^{\circ}C{\pm}1.0^{\circ}C$ using a potentiostat and an electrochemical impedance spectroscope. The potentiodynamic test was performed with a scanning rate of $1.667mV\;s^{-1}$ from -1,500 to 2,000 mV. A frequency range of $10^{-1}$ to $10^5Hz$ was used for the electrochemical impedance spectroscopy (EIS) measurements. The amplitude of the AC signal was 10 mV, and 5 points per decade were used. The morphology and structure of the samples were examined using field-emission scanning electron microscopy and thin-film X-ray diffraction. The elemental analysis was performed using energy-dispersive X-ray spectroscopy. Result: The PEO-treated surface exhibited an irregular pore shape, and the pore size and number of the pores increased with an increase in the Mn concentration. For the PEO-treated surface, a higher corrosion current density ($I_{corr}$) and a lower corrosion potential ($E_{corr}$) was obtained as compared to that of the bulk surface. However, the current density in the passive regions ($I_{pass}$) was found to be more stable for the PEO-treated surface than that of the bulk surface. As the Mn concentration increased, the capacitance values of the outer porous layer and the barrier layer decreased, and the polarization resistance of the barrier layers increased. In the case of the Mn/Ca-P coatings, the corroded surface was found to be covered with corrosion products. Conclusion: It is confirmed that corrosion resistance and polarization resistance of PEO-treated alloy increased as Mn content increased, and PEO-treated surface showed lower current density in the passive region.

• Applied Chemistry for Engineering
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• v.26 no.3
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• pp.372-376
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• 2015

6-MQCC (Cr(VI)-6-methylquinoline) complex was synthesized by the reaction of 6-methylquinoline with chromium(VI) trioxide in 6 M HCl. The structure was characterized using IR (Infrared Spectroscopy) and ICP (Inductively Coupled Plasma) analysis. The oxidation of benzyl alcohol using 6-MQCC in various solvents showed that the reactivity increased with the increase of the dielectric constant, in descending order of DMF > acetone > chloroform > cyclohexene. In the presence of DMF solvent with acidic catalyst such as sulfuric acid ($H_2SO_4$), 6-MQCC oxidized benzyl alcohol (H) and its derivatives ($p-OCH_3$, $m-CH_3$, $m-OCH_3$, m-Cl, $m-NO_2$) were effectively oxidized. Electron-donating substituents accelerated the reaction rate, whereas electron acceptor groups retarded the reaction rate. The Hammett reaction constant (${\rho}$) was -0.69 (308 K). The observed experimental data was used to rationalize the fact that the hydride ion transfer occurred at the rate-determining step.

• Analytical Science and Technology
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• v.12 no.5
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• pp.447-459
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• 1999

A study was conducted to compare three analytical methods for determination of hexavalent chromium in the welding fume. Precision and accuracy arc documented for colorimetric, ion chromatographic, and inductively coupled plasma-optical emission spectroscopic method. Evidence is presented that welding fume can affect the oxidation of trivalent chromium. A simple sonication extraction method, proposed in this study, instead of hot alkaline extraction has the advantage of minimizing the potential for chromium oxidation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.4
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• pp.591-597
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• 2003

To investigate antioxidative and antiaging effects of yellow and black soybeans in vivo system, male SD rats (n＝24) were fed the diets containing casein (C), yellow soybean (YS) or black soybean (BS) for 8 weeks. Experimental groups showed the preventive effect on lipid and protein oxidation, especially protein oxidation of plasma was significantly inhibited in BS group. SOD and catalase activities were not different among the groups, but hepatic glutathione peroxidase (GSH-px) activity was significantly lowered in YS and BS groups compared with control group. The contents of superoxide anion radical in cytosol were significantly lowered in experimental groups compared with control group. And hydroxyl radical was slightly lowered in soybean groups. Lipofuscin accumulation on the heart and eyes of rats was effectively inhibited by yellow soybean and black soybean, respectively. In conclusion, these results suggest that yellow soybean and black soybean have the antioxidative/antiaging effect in vivo system and they have similar activities despite different color of seed coat.

• BMB Reports
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• v.42 no.10
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• pp.667-672
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• 2009

Plasma concentrations of adiponectin have been shown to be decreased in patients with obesity, cardiovascular diseases, hypertension and metabolic syndrome. Recent studies have found that adiponectin reduces lipid accumulation in macrophage foam cells which may impact the development of atherosclerosis. However, it remains unclear whether adiponectin is involved in the process of lipid accumulation during myogenesis. Using C2C12 myoblasts, we investigated the effect of adiponectin on intramyocellular lipid accumulation during myogenesis. The results showed that intracellular lipid accumulation is significantly decreased during C2C12 differentiation, apparently due to increased fatty acid oxidation and decreased fatty acid synthesis during this process. C2C12 cells transiently transfected with adiponectin gene showed reduced lipid accumulation as compared to controls. Further experiments demonstrated that adiponectin can suppress lipid accumulation by increasing fatty acid oxidation during C2C12 myogenesis.

• Applied Chemistry for Engineering
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• v.27 no.1
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• pp.110-114
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• 2016

Cr(VI)-pyrazine complex (PZCC) was synthesized by the reaction of pyrazine with chromium (VI) trioxide in 6 M HCl. The structure was characterized using IR spectroscopy and inductively coupled plasma (ICP). The oxidation of benzyl alcohol using PZCC in various solvents showed that the reactivity increased with the increase of the dielectric constant, in the order: N,N'-dimethylform-amide > acetone > chloroform > cyclohexene. In the presence of N,N'-dimethylformamide solvent with an acidic catalyst such as sulfuric acid ($H_2SO_4$ solution), PZCC oxidized benzyl alcohol (H) and its derivatives ($p-OCH_3$, $m-CH_3$, $m-OCH_3$, m-Cl, $m-NO_2$). Electron-donating substituents accelerated the reaction rate, whereas electron acceptor groups retarded the reaction rate. Hammett reaction constant (${\rho}$) was -0.70 (308 K). The observed experimental data were used to rationalize the hydride ion transfer in the rate-determining step.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.165-165
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• 2013

Nickel oxide was deposited on mesoporous silica by atomic layer deposition (ALD) consisting of sequential exposures to Ni(cp)2 and $H_2O$. NiO/silica samples were characterized by inductively coupled plasma-mass spectroscopy (ICP-MS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), etc. The flow-type reactor was used to measure activity of NiO/silica catalyst for catalytic combustion of toluene. The activity of NiO/silica catalyst was evaluated in terms of toluene removal efficiency and selectivity to $CO_2$ and compared with those of bare nickel oxide nanoparticles. In order to investigate influence of reaction temperature on combustion aspect, the catalytic combustion experiments were carried out at various temperatures. We show that both bare and supported NiO can be efficient catalysts for total oxidation of toluene at a temperature as low as $250^{\circ}C$.