• Korean Chemical Engineering Research
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• v.50 no.2
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• pp.217-222
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• 2012

The synthesis of dimethyl carbonate(DMC) is a promising reaction for the use of naturally abundant carbon dioxide. DMC has gained considerable interest owing to its versatile chemical reactivity and unique properties such as high oxygen content, low toxicity, and excellent biodegradability. In this study, the synthesis of DMC through the transesterification of ethylene carbonate(EC) with methanol was investigated by using ionic liquid and metal oxide catalysts. The screening test of different catalysts revealed that choline hydroxide ([Choline][OH]) and 1-n-butyl-3-methyl imidazolium hydroxide([BMIm][OH]) had better catalytic performance than metal salts catalysts such as MgO, ZnO and CaO. The effects of reaction parameters such as reaction temperature, MeOH/EC mole ratio, and carbon dioxide pressure on the reactivity of [Choline][OH] catalyst were discussed. High temperature and high MeOH/EC mole ratio were favorable for high conversion of EC. However, the yield of DMC showed a maximum when carbon dioxide pressure was 1.34 MPa, and then it decreased for higher carbon dioxide pressure. Zinc chloride($ZnCl_2$) was used as co-catalyst with the ionic liquid catalyst. The mixed catalyst showed a synergy effect on the EC conversion and DMC yield probably due to the acid-base properties of the catalysts.

• Journal of the Korean Magnetics Society
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• v.19 no.3
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• pp.113-119
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• 2009

$^{57}Fe_xCu_{1-x}O$(x = 0.0, 0.02) powders were prepared by sol-gel method and their crystallographic and magnetic hyperfine properties have been studied using X-ray diffraction and $M{\ddot{o}}ssbauer$ spectroscopy (MS). The crystal structure of the samples is found to be monoclinic without any secondary phases and their lattice parameters increase with increasing annealing temperature ($T_A$), which is attributed to an increase in oxygen-vacancy content. MS measurements at room temperature indicate that $Fe^{3+}$ ions substitute $Cu^{2+}$ sites and ferromagnetic phase grow with increasing $T_A$. Magnetic hyperfine and quadrupole interactions of $^{57}Fe_{0.02}Cu_{0.98}O$ ($T_A=500^{\circ}C$) in the antiferromagnetic state at 17 K have been studied, yielding the following results: $H_{hf}=426.94\;kOe$, ${\Delta}E_Q=-3.67\;mm/s$, I.S.=0.32 mm/s, ${\theta}=65^{\circ}$, ${\phi}=0^{\circ}$, and ${\eta}=0.6$.

• The Korea Journal of Herbology
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• v.35 no.4
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• pp.25-36
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• 2020

Objective : Reflux esophagitis is a disease caused by the reflux of gastric acid and inflammation due to unstable gastroesophageal sphincter. The aim of the present study was to clarify the effect of Phellodendri Cortex (PC) on chronic reflux esophagitis (CRE) in rats. Methods : The anti-oxidant activity of PC was measured by total polyphenol, total flavonoid contents, 1, 1-diphenyl-2-picrylhydrazyl (DPPH), and 2, 2'-azinobis-3-ethyl-enzothiazoline-6-sulfonic acid (ABTS) radical scavenging activity. A CRE was established surgically in SD rats. And then CRE rats were treated with water or PC 200 mg/kg body weight for 14 days. Besides, the anti-oxidant and inflammatory protein levels were evaluated using western blotting. Results : PC reduced esophagus tissues injury. The total polyphenol (36.05 ± 0.25 mg/g) and total flavonoid (72.90 ± 0.61 mg/g) of PC showed a high content. PC strongly reduced radical scavenging activities (DPPH IC₅₀ 43.58 ± 1.54 ㎍/㎖; ABTS IC₅₀ 36.75 ± 0.35 ㎍/㎖). Moreover, reactive oxygen species (ROS) and peroxynitrite (ONOO^-) levels in serum, the protein expression of inducible nitric oxide synthases (iNOS) were significantly reduced. In addition, the protein expression of NADPH oxidases related to oxidative stress were significantly reduced in PC compared to CRE control. PC effectively reduced inflammatory factors including, TNF-α, and IL-6 via NF-κBp65 inactivation through the inhibition of p-IκBα and increased anti-oxidant enzyme such as HO-1, SOD, catalase, and GPx-1/2 via Nrf2 activation. Conclusions : Taken together, these results show that PC can alleviate the esophageal mucosal ulcer though the inhibition of NF-κB inflammatory and the enhancement of Nrf2 anti-oxidant pathway.

• YAKHAK HOEJI
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• v.45 no.5
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• pp.513-521
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• 2001

The chronic cholestasis induce to biliary liver fibrosis (cirrhosis) and the increased products of ROS(reactive oxygen species) cause to the liver damage. In this study ; the antioxidant and antifibrotic effect of dried extracts of oriental medicine (DW) was investigated under the liver fibrotic (cirrhotic) condition. The female Sprague-Dawley rats were divided in 5 groups (Normal, Op-2, Op-4, OpDW-2, OpDW-4). Except for normal group, the rats were induced to biliary liver fibrosis (cirrhosis) by the operation of bile duct ligation/scission (BDU/S) and were observed in 2 weeks or 4 weeks. And the prepared DW was treated p.o.2 ml/day/rats in 2 weeks or 4 weeks for OpDW groups. At the time of sacrifice, the liver, kidney, spleen were weighed and the ratio of organ weight/body weight was calculated. The MDA, the hyp and biochemical parameters (GOT GTP, ALP, t-bili) were measured in sera and liver tissue of rats. The biochemical change was observed on liver tissue. In the result, the hepatomegaly and spleenomegaly appeared in all BDL/S operated rats, and significantly lower liver weight was observed in OpDW-4 group compared with in Op-4 group (p<0.05). The level of clinical parameters in sera of all liver fibrosis (cirrhosis) developed rats was higher than in normal group. Especial1y, the value of GOT in OpDW-2 group and ALP in OpDW-4 group showed significantly lower than in Op-2 group and Op-4 group (p<0.01, p<0.005). The content of hyp in all operation groups was significantly higher than in normal group (p<0.05∼<0.005), and showed significantly lower value in the OpDW-4 group than in Op-4 group (p<0.05). The product of lipid peroxidationUDA) increased significantly under the fibrotic(cirrhotic) condition (p<0.05∼ <0.005), and the MDA value in OpDW-4 group decreased significantly in Op-4 group (p<0.005). The histological change (bile duct proliferation, fibrosis, collagen bundle) was similarly observed in Op-2 group and in OpDW-2 group, but the weak fibrosis and bile duct proliferation were observed in OpDW-4 group compared with in Op-4 group. In conclusion, lipid peroxidation and severe liver damage were activated by bile duct obstruction, and the measurement of MDA and hap can be useful monitor for the screening of antioxidant and antifibrotic effect in experimental liver fibrosis (cirrhosis). The 4 weeks treatment with DW extracts suppressed lipid peroxidation and inhibited fibrotic (cirrhotic) process in BDL/S operated rats.

• Korean Journal of Food Science and Technology
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• v.44 no.1
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• pp.82-88
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• 2012

Chrysanthemum indicum L. (Asteraceae) is a traditional herbal medicine that has been used for the treatment of inflammation, hypertension, and respiratory diseases due to its strong antagonistic activity against inflammatory cytokines. The effects of Chrysanthemum indicum L. Extract (CIE) for increasing cell growth, alkaline phosphatase (ALP) activity, and collagen content were totally inhibited, suggesting that the effect of CIE might be partly involved with estrogen activity. Furthermore, the protective effects of CIE on the response of osteoblasts to oxidative stress were evaluated. Osteoblastic MC3T3-E1 cells were incubated with hydrogen peroxide and/or CIE, and markers of osteoblast function and oxidative damage were examined. CIE significantly increased cell survival, ALP activity, and calcium deposition, and decreased the production of Reactive Oxygen Species (ROS) and Tumor Necrosis Factor-${\alpha}$ (TNF-${\alpha}$) in osteoblasts. Taken together, these results indicate that the enhancement of osteoblast function by CIE may prevent osteoporosis and inflammatory bone diseases.

• Membrane Journal
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• v.21 no.1
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• pp.62-71
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• 2011

Highly enriched oxygen is used in energy-efficient combustion due to decreased non-flammable nitrogen, while high purity nitrogen is used for explosion proof in the LNG ships and keeping the freshness of green stuffs. Membrane technology can be used in these $O_2$ and $N_2$ generation with low energy consumption. In this study, PES was used as a membrane material and 1-methyl-2-pyrollidone (NMP) and acetone were employed as a good solvent and nonsolvent addictive (swelling agent to PES), respectively. Dope solutions were prepared by changing the content of acetone (0, 6.5, 15, 25, 31.5 wt%) in 37 wt% PES solutions. Hollow fiber spinning was performed at 0~10 cm of air-gap distances for each dope solution. $O_2/N_2$ selectivity and permeability were investigated by comparing of hollow fibers coated or not by silicons. $O_2/N_2$ selectivity increased and permeance of $O_2$ and $N_2$ decreased with increasing air-gap height independently of acetone addictions. Optimized PES hollow fibers were obtained with 37/6.5/56.5 wt% PES/acetone/NMP dope solution and 10 cm air-gap, which showed 7.3 of $O_2/N_2$ selectivity and 4.3 GPU of $O_2$ permeability after silicon coating.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.5
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• pp.675-681
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• 2013

Home-made broccoli Kochujang (HMBK) was prepared with the addition of 5% broccoli leaf powder. Its physicochemical and functional properties were measured in extracts (80% methanol, 80% ethanol, and distilled water) and compared with home-made Kochujang (HMK) and factory-produced Kochujang (FPK). Total phenolic content (TPC) was 22% higher in methanol extract from HMBK (524.2 GAE/100 g) compared to HMK (431.0 GAE/100 g). TPC was 8% higher in ethanol extract from HMBK (541.9 GAE/100 g) compared to HMK (499.9 GAE/100 g). DPPH radical scavenging activity was 1.6 times higher in the methanol extracts from HMBK than HMK. In contrast there was no difference in DPPH radical scavenging activity between HMBK and HMK. Oxygen radical absorbance capacities in methanol and ethanol extracts from HMBK were similar to HMK, but both were higher than extracts from FPK (55% and 23% higher, respectively). Inhibition of angiotensin I converting enzyme activity in methanol extracts from HMBK was similar to HMK, but it was 2.6 times higher than inhibition activities from FPK. Interestingly, only ethanol extract from HMBK showed a 10.7% and 18.3% inhibition on cell growth of the human colon adenocarcinoma grade II cell line (HT-29) and human lung carcinoma cell line (NCI-H1229), respectively. These results indicate home-made Kochujang with broccoli leaf powder contains high total phenolics, antioxidant activities, and cancer cell growth inhibition activities.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.12
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• pp.1047-1053
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• 2016

In this study, welding of pure titanium was carried out by using a continuous wave fiber laser with a maximum output of 6.3 kW. Because brittle regions form easily in titanium as a result of oxidation or nitriding, the weld must be protected from the atmosphere by using an appropriate shielding gas. Experiments were performed by changing the type and the flow rate of shielding gases to obtain the optimal shielding condition, and the weldability was then evaluated. The degree of oxidation and nitriding was distinguished by observing the color of beads, and weld microstructure was observed by using an optical microscope and a scanning electron microscope. The mechanical properties of the weld were examined by measuring hardness. When the weld was oxidized or nitrified, the bead color was gray or yellow, and the oxygen or nitrogen content in the bead surface and overall weld tended to be high, as a result of which the hardness of the weld was thrice that of the base metal. A sound silvery white bead was obtained by using Ar as the shielding gas.

• Korean Journal of Food Science and Technology
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• v.46 no.4
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• pp.483-488
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• 2014

To examine the physiological effects of broccoli (Brassica oleracea var. italica) leaf, the bioavailable compounds in broccoli leaf extract, and its in vitro neuroprotective effects against $H_2O_2$-induced oxidative stress were examined in this study. The chloroform fraction of broccoli leaf extract had the highest total phenolic content of all the fraction than others, and the highest 2,2"-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical-scavenging activity and malondialdehyde (MDA) inhibitory effect. Intracellular reactive oxygen species (ROS) accumulation resulting in $H_2O_2$-treated in PC12 cells was significantly lower when the chloroform fraction was present in the medium compared to that in PC12 cells treated with $H_2O_2$ alone. In a cell viability assay performed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), the chloroform fraction showed protective effects against $H_2O_2$-induced neurotoxicity and inhibited lactate dehydrogenase (LDH) release into the medium. High-performance liquid chromatography (HPLC) analysis showed that ferulic acid was the predominant phenolic compound in chloroform fraction of broccoli leaf.

• Journal of Dairy Science and Biotechnology
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• v.35 no.4
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• pp.244-248
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• 2017

The effects of ultrasonic (1.2~1.7 kJ/g TS) pretreatment on the solubilization of dairy and livestock sludge were separately evaluated to investigate the possibility of recycling dairy sludge as a potential source of organic carbon. Compared to other industrial wastewater and sewage sludge, dairy sludge has higher organic matter content and no toxic materials. The solubilization rates of dairy and livestock sludge, at a specific energy input of 1.7 kJ/g TS, were 14.5% and 10.6%, respectively. After the 90-minute ultrasonic treatment, the soluble COD (chemical oxygen demand) increased about 7.1 times that of the initial SCOD, at an increase rate of $0.022m^{-1}$. In comparison, the increase in soluble nitrogen, which was ~3.4 times that of the initial soluble nitrogen concentration, was much smaller than the increase in SCOD; thus, the C/N ratio increased from 4.0 to 8.7.