• Korean Journal of Food Science and Technology
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• v.41 no.1
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• pp.87-92
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• 2009

The antioxidant properties and protective effects of Inula britannica on ${H_2}{O_2}$-induced SH-SY5Y neuroblastoma cell damage were investigated. A series of solvent fractions, including hexane(Fr.H), petroleum ether, chloroform, ethyl acetate(Fr.EA), and water fraction(Fr.W), were prepared from the 70% methanol extracts of Inula britannica. Fr.W had the highest total contents of phenolics and flavonoids, followed by Fr.EA. The antioxidant properties of the fractions were also evaluated by analyzing their scavenging activities on 1,1-diphenyl-2-picrylhydrazyl(DPPH) radicals, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals, and nitric oxide. Fr.W showed the strongest activities in all assays. The concentrations of Fr.W that resulted in 50% reductions of the DPPH and ABTS radicals were 20.7 ${\mu}g$/mL and 39.4 ${\mu}g$/mL, respectively. Fr.W showed the weakest cytotoxic activities on the SH-SY5Y cells, whereas it effectively protected ${H_2}{O_2}$-induced cell death, increasing cell survival by 35.0-77.0% at a concentration range of 62.5-250 ${\mu}g$/mL. In this range, Fr.W also significantly decreased intracellular ROS levels by 34-39%. Overall, the antioxidant properties of Inula britannica can contribute to rescuring neuronal cells from oxidative stress-induced cell injury.

• Journal of the Microelectronics and Packaging Society
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• v.17 no.1
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• pp.33-39
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• 2010

Printing technologies have been indicated as alternative methods for patterning conductive, semi-conductive or insulative materials on account of their low-cost, large-area patternability and pattern flexibility. For application of the printing technologies in manufacture of semiconductor or display modules, ink or paste composed of nanoparticles, solvent and additives are basically needed. Here, we report recent advances in eco-friendly nano-ink technology for semiconductor and display technology. Then, we will introduce an eco-friendly ink formation technology developed in our group with an example of manufacturing $SiO_2$ nanopowders and inks. We tried to manufacture ultrafine $SiO_2$ nanoparticles by applying a low-temperature synthetic method, and then attempted to fabricate the printed $SiO_2$ film onto the glass substrate to see whether the $SiO_2$ nanoparticles are feasible for the printing or not. Finally, the electrical characteristics of the films were measured to investigate the effect of the manufacturing parameters.

• Microbiology and Biotechnology Letters
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• v.43 no.4
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• pp.367-372
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• 2015

This study was aimed at determining the antioxidant and antimicrobial effects of solvent extracts from Asparagus cochinchinensis. The Asparagus cochinchinensis was extracted with water, methanol, ethanol, n-hexane, dichloromethane, ethyl acetate, and ether. The antimicrobial activity of these extracts was determined by modified well diffusion methods against 4 species of respiratory disease bacteria (Staphylococcus aureus, Escherichia coli, Staphylococcus epidermidis, and Pseudomonas aeruginosa). In addition, the amount of total polyphenol and flavonoid content, and antioxidant activity was evaluated. Ethyl acetate extract of A. cochinchinensis exhibited higher antimicrobial activity against tested microorganisms than water, methanol, ethanol, n-hexane, dichloromethane, and ether extracts. For antioxidant activity, the ethyl acetate extract of A. cochinchinensis exhibited a notable effect on the scavenging of superoxide against DPPH ($IC_{50}=3.81mg/ml$). Finally, the total polyphenol and flavonoid contents were $14{\pm}0.7mg/g$, and $0.50{\pm}0.13mg/g$, respectively. These results can be regarded as basic research into A. cochinchinensis for the prevention of respiratory diseases. The results indicate that A. cochinchinensis may be utilized as a nutraceutical for respiratory diseases when the physiologically active substances of A. cochinchinensis are increased by further study.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.6
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• pp.387-395
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• 2014

A highly sensitive analytical method based on stir bar sorptive extraction (SBSE) technique and gas chromatography/tandem mass spectrometry (GC-MS/MS) has been developed, allowing the simultaneous multi-analyte determination of 11 synthetic fragrances (SFs) in water samples. The stir bar coated with polydimethylsiloxane (PDMS) was added to 40 mL of water sample at pH 3 and stirred at 1,100 rpm for 120 min. Other SBSE parameters (salt effect and presence of organic solvent) were optimised. The method shows good linearity (coefficients > 0.990) and reproducibility (RSD < 10.9%). The extraction efficiencies were above 83% for all the compounds. The limits of detections (LOD) and limits of quantification (LOQ) were 2.1~4.1 ng/L and 6.6~12.9 ng/L, respectively. The developed method offers the ability to detect 11 SFs at ultra-low concentration levels with only 40 mL of sample volume. Matrix effects in tap water, river water, wastewater treatment plant (WWTP) final effluent water and seawater were investigated and it was shown that the method is suitable for the analysis of trace level of 11 SFs. The method developed in the present study has the advantage of being rapid, simple, high-sensitive and both user and environmentally friendly.

• Applied Biological Chemistry
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• v.47 no.2
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• pp.265-269
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• 2004

This study was conducted to develop physiologically active plant materials from medicinal plants. Crude extracts and solvent fractions prepared from Lysimachia cletroides Duby were tested for their antioxidant and antihypertensive activities. For ellucidating antioxidant potential, inhibition rate on linoleic acid peroxidation, as well as scavenging activities on superoxide anion and 1,1-dipicrylphenylhydrazyl (DPPH) radical were evaluated. For analyzing antihypertensive effect, inhibitory activity on angiotensin converting enzyme (ACE) was done. Methanol extract of L. cletroides showed potent inhibition activity of 83% on linoleic acid peroxidation, which was more effective than -2% of ${\alpha}-tocopherol$ at $25\;{\mu}g/ml$. Methanol and water extracts exhibited strong scavenging activities of $86{\sim}109%$ and $96{\sim}122%$ on superoxide anion radical which was higher than $-4{\sim}69%$ of ascorbic acid at $5{\sim}200\;{\mu}g/ml$. Hexane, ether and ethylacetate fractions possessed 133, 100 and 88% inhibitory activities on ACE at $4,000\;{\mu}g/ml$, respectively. From the results, it was expected that Lysimachia cletroides could be a new antioxidant and antihypertensive resource.

• Polymer(Korea)
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• v.28 no.5
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• pp.382-390
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• 2004

One of the significant natural bioactive materials is demineralized bone particle (DBP) whose has a powerful induce. of new bone growth. In this study, we developed the DBP loaded poly-lactide (PLA) and poly(L-lactide-co-glycolide) (PLGA) scaffolds for the possibility of the application of the tissue engineered bone. PLA/DBP and PLGA/DBP scaffolds were prepared by solvent casting/salt leaching method and were characterized by porosimeter, scanning electron microscopy. BMSCs were stimulated by osteogenic medium and characterized by histological stained Wright-Giemsa, Alizarin red, von Kossa, and alkaline phosphate activity (ALP). DBP impregnated scaffolds with BMSCs were implanted into the back of athymic nude mouse to observe the effect of DBP on the osteoinduction compared with control scaffolds. It can be observed that the porosity was above $90.2\%$ and the pore size was above 69.1$\mu$m. BMSCs could be differentiated into osteoprogenitor cells as result of wright-giemsa, alizarin red, von Kossa and ALP staining. In in vivo study, we could observed calcification region in PLA/DBP and PLGA/DBP groups, but calcification did not occur almost in control scaffolds. From these results, it seems that DBP as well as BMSCs play an important role for bone induction in PLA/DBP and PLGA/DBP scaffolds.

• Applied Chemistry for Engineering
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• v.9 no.5
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• pp.634-638
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• 1998

Monodisperse, spherical $PMSQ/TiO_2$ composite fine powders were prepared by modified sol-gel process where 300 nm $TiO_2$ fine powders were used as seed particles for hetero-condensation with hydrolyzed MTMS (Methyltrimethoxysilane). The reaction was carried out under $N_2$ atmosphere at ambient temperature using $NH_3$ as a catalyst. Methanol was used as a solvent. Powder was obtained by the filtration of the solution with a glass filter and washing with acetone. The stirring rate, reaction temperature, $[H_2O]/[MTMS]$ and $[MTMS]/[TiO_2]$ ratio were varied to investigate shapes and sizes of particles. Monodisperse particles of $1-2{\mu}m$ diameter were obtained with [MTMS]=0.2 M, $[NH_3]=0.6M$, $[H_2O]/[MTMS]=100$, $[MTMS]/[TiO_2]=10-50$ at ambient temperature with mild stirring condition. These composite particles had a contact angle of almost 180 degree contact angle with water, which proves their excellent hydrophobicity. The study of UV absorption spectra showed that they have UV protecting effect.

• Applied Chemistry for Engineering
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• v.9 no.5
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• pp.734-741
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• 1998

Electrode characteristics were studied in the interface between sample solutions and $K^+$ ion selective PVC membrane electrodes containing neutral carriers, dibenzo-18-crown-6(D18Cr6) and valinomycin(Val). The effect of doping of base electrolytes, the chemical structure and the content of carrier, variation of plasticizer, membrane thickness, and concentration variation of sample solution on the response characteristics of electrode such as the measured Nernstian slope, the detection limit, the linear response range, and potentiometric selectivity coefficients, were studied. In order to synthesize the membrane D18Cr6 and Val as neutral carriers were used, and complex between the carrier and $K^+$ ions were used as active materials. PVC membrane electrodes were made of plasticizers (DBP, DOS, and DBS), the base electrolyte[potassium tetraphenylborate(KTPB)], and solvent(THF). The chemical structure of carrier D18Cr6 was best for electrode and ideal electrode characteristics were appeared especially in case of doping of TPB. The optimum carrier content was about 3.23 wt % in case of D18Cr6 and Val. DBP was best as a plasticizer. As membrane thickness decreased the electrode characteristics was improved. But its characteristics were lowered below the optimum membrane thickness because of the elution of carrier, deterioration of membrane strength, etc. In the case of D18Cr6, the selectivity coefficients by the mixed solution method for the $K^+$ ion were in the order of $NH_4{^+}>Ca^{2+}>Mg^{2+}>Na^+$.

• Korean Journal of Food Science and Technology
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• v.38 no.1
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• pp.109-113
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• 2006

Antioxidant compound(s) were identified from the ethanol extract of wild grape (Vitis coignetiea) seed. Organic solvent fractions of n-hexane, chloroform, ethyl acetate and butanol were obtained from the ethanol extract of wild grape seed, among which ethyl acetate fraction showed the strongest reducing power. Ethyl acetate fraction was further purified through ODS column chromatography and HPLC, and isolated antioxidative active compound was identified through $^1H-NMR$ as (+)-catechin (52.7 g/100 g). (+)-Catechin and ethyl acetate fraction both showed approximately 80% scavenging effect. These results indicated (+)-catechin in the ethyl acetate fraction synergetically interacts with unknown antioxidative compound(s).

• Resources Recycling
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• v.26 no.4
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• pp.79-87
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• 2017

Extraction and separation behaviors of La, Ce, Pr, Nd and Sm from light rare earth multi - component mixed solutions by Cyanex 572 were studied. As extractant concentration increased, the $pH_{50}$ values of all the five components decreased. When extractant concentration was larger than 0.6 M, the separation factor of La and Ce, Nd and Sm was higher than 10, while the separation factor between Ce and Pr, Pr and Nd was as low as 0.5~2.2. Addition of TBP to the 0.6 M Cyanex 572 had little synergistic effect on the phase separation rate and separation factor. From the analysis of experiment results, group separation of [La]/[Pr, Nd, Sm] and [Pr, Nd]/[Sm] could be possible, but in case of the group separation between [La, Ce] and [Pr, Nd] was not available because of the low separation factor between Ce and Pr.