Carbon supports for dispersed platinum (Pt) electrocatalysts in direct methanol fuel cells (DMFCs) are being continuously developed to improve electrochemical performance and catalyst stability. However, carbon supports still require solutions to reduce costs and improve catalyst efficiency. In this study, we prepare well-dispersed Pt electrocatalysts by introducing titanium dioxide (TiO2) into biomass based nitrogen-doped carbon supports. In order to obtain optimized electrochemical performance, different amounts of TiO2 component are controlled by three types (Pt/TNC-2 wt%, Pt/TNC-4 wt%, and Pt/TNC-6 wt%). Especially, the anodic current density of Pt/TNC-4 wt% is 707.0 mA g−1 pt, which is about 1.65 times higher than that of commercial Pt/C (429.1 mA g−1 pt); Pt/TNC-4wt% also exhibits excellent catalytic stability, with a retention rate of 91 %. This novel support provides electrochemical performance improvement including several advantages of improved anodic current density and catalyst stability due to the well-dispersed Pt nanoparticles on the support by the introduction of TiO2 component and nitrogen doping in carbon. Therefore, Pt/TNC-4 wt% may be electrocatalyst a promising catalyst as an anode for high-performance DMFCs.

Nb-doped TiO2(NTO) coated NiCrAl alloy foam for hydrogen production is prepared using ultrasonic spray pyrolysis deposition(USPD) method. To optimize the size and distribution of NTO particles based on good physical and chemical stability, we synthesize particles by adjusting the weight ratio of the Nb precursor solution(5 wt%, 10 wt% and 15 wt%). The morphological, chemical bonding, and structural properties of the NTO coated NiCrAl alloy foam are investigated by X-ray diffraction(XRD), X-ray photo-electron spectroscopy(XPS), and Field-Emission Scanning Electron Microscopy(FESEM). As a result, the samples of controlled Nb weight ratio exhibit a common diffraction pattern at ~25.3o , corresponding to the(101) plane, and have chemical bonding(O-Nb=O) at 534 eV. The NTO particles with the optimum weight ratio of N (10 wt%) show a uniform distribution with a size of ~18.2-21.0 nm. In addition, they exhibit the highest corrosion resistance even in the electrochemical stability estimation. As a result, the introduction of NTO coated NiCrAl alloy foam by USPD improves the chemical stability of the NiCrAl alloy foam by protecting the direct electrochemical reaction between the foam and the electrolyte. Thus, the optimized NTO coating can be proposed for excellent protection of NiCrAl alloy foam for hydrocarbon-based steam methane reforming(SMR).

To improve the performance of carbon nanofibers as electrode material in electrical double-layer capacitors (EDLCs), we prepare three types of samples with different pore control by electrospinning. The speciments display different surface structures, melting behavior, and electrochemical performance according to the process. Carbon nanofibers with two complex treatment processes show improved performance over the other samples. The mesoporous carbon nanofibers (sample C), which have the optimal conditions, have a high sepecific surface area of 696 m2 g−1, a high average pore diameter of 6.28 nm, and a high mesopore volume ratio of 87.1%. In addition, the electrochemical properties have a high specific capacitance of 110.1 F g−1 at a current density of 0.1 A g−1 and an excellent cycling stability of 84.8% after 3,000 cycles at a current density of 0.1 A g−1. Thus, we explain the improved electrochemical performance by the higher reaction area due to an increased surface area and a faster diffusion path due to the increased volume fraction of the mesopores. Consequently, the mesoporous carbon nanofibers are demonstrated to be a very promising material for use as electrode materials of high-performance EDLCs.

Background : The 1,2-unsaturated PAs, reported to be widely present in medicinal plants belonging to Asteraceae, Boraginaceae, and Fabaceae, cause hepatotoxicity and genotoxicity in humans and animals. Hence, there is a need for an analytical method that allows these dangerous plant toxins to be determined. In this study, we developed a method that can be used for the rapid and accurate determination of nine toxic PAs in medicinal plants using ultra-pressure liquid chromatography–electrospray ionization–quadrupole–time-of-flight mass spectrometry (UPLC-ESI-Q-TOF). Methods and Results : The compounds were eluted onto a C18 column with 0.1% formic acid and acetonitrile, and separated with good resolution within 11 min. all analytes was characterized by its precursor ions generated by ESI-Q-TOF and fragment ions produced by collision-induced dissociation (CID), which were used as a reliable database. The proposed analytical method was verified with reference to the ICH guidelines. The proposed UPLC-ESI-Q-TOF method was applied to four medicinal plants, and lycopsamin, echimidine, senkirkine and senecionine were detected by matching with reference standard, and additional six PAs were tentatively identified though chemical profiling. In addition, the QuEchERS method was the most efficient in comparison with methods like hot water and methanol in extraction efficiency of pyrrolizidine alkaloids. Conclusion : The our proposed method can determine PAs rapidly and accurately in medicinal plants and will be utilize as an important data for other researchers who need analytical information of PAs.

Background : Turmeric (Curcuma longa L.) and black pepper (Piper nigrum L.) have traditionally been used as Asian medicinal and culinary herb. Curcumin, a major compound of turmeric, has been known to have antitumor activity. However, curcumin is bioavailable because it is rapidly metabolized and released from the body. Therefore, the addition of adjuvants such as piperine, a potent inhibitor of drug metabolism, is one of the ways to increase the bioavailability of curcumin. Methods and Results : The yields of turmeric and black pepper ethanolic extracts (TM and BP) are 18.2 and 8.2% (w/w), respectively. The EC50 values of A549 and NCI-H292 cells exposed to TM were 77.8 ㎍/㎖ and 92.0 ㎍/㎖, respectively. No significant cytotoxicity was observed up to the 400 ㎍/㎖ in the A549 and NCI-H292 exposed to BP. Based on the central composite design, the co-treatment of TM and BP enhanced the cytotoxicity of A549 and NCI-H292 cells. The optimal combination concentration (optimal EC50 value) of TM and BP calculated by the response surface methodology assay were 48.5 and 241.7 ㎍/㎖. The conbination index assay confirmed that the cytotoxic effect at optimal combinatino concentration was due to the synergistic effect. Conclusion : We hypothesized that co-treatment of TM and BP enhanced cytotoxicity more than single treatment of TM against lung cancer cells, and cell death at this time may synergetic cytotoxicity effects associated with curcumin metabolism.

Background: The present study was carried out to asses whether mulberry leaves (MLs) have the potential to inhibit the mutagenic effect of cigarette smoke condensates (CSCs). Methods and Results: ML powder was extracted with 70% ethanol, and a yield of 35.1% by weight was obtained. The 70% ethanol extract of ML was further extracted sequentially using diethyl ether, chloroform, butanol, dichloromethane and water. The crude 70% ethanol extract of MLs and its solvent fractions did not show any mutagenic effect when tested at concentrations up to 1 ㎎/ plate against Salmonella typhimurium TA98. In contrast, the crude 70% ethanol extract showed an inhibitory activity against the mutagenicity of CSCs in the presence of S-9 mixture. Among the solvent fractions, the diethyl ether fraction showed the highest inhibitory activity, which increased in a dose-dependent manner, inhibiting mutagenesis by approximately 97.1% at a concentration of 1㎎/plate. Conclusions: In this study, we found that a crude 70% ethanol extract of MLs and the diethyl ether fraction themselves are potentially not mutagenic, but inhibit the mutagenic effect of CSCs.

Background : The effects of heat treatments on the phycochemical charateristics and antioxidant activities of ginkgo nuts were investigated by roasting at various temperatures (150, 180, and 210℃) for 60 min. Methods and Results : For each roasting temperatures, pH, total acidity, chromaticity, total cyanide content, reducing power, total polyphenol content, 2,2’-diphenyl-1-picrylhydrazyl (DPPH) and 2,2’-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activities were compared and analyzed. As the roasting temperature and time increased, the pH and total cyanide content decreased from 7.32 to 6.31 and from 697 to 282 ㎍/㎎, respectively, while total acidity increased from 0.40 to 0.84%. There was an 11 or more color difference (ΔE) between the non-heated ginkgo nut and heated ginkgo nuts, indicating a remarkable color difference. The antioxidant activities, including reducing power, total polyphenol content, and DPPH and ABTS radical scavenging activities increased rapidly at 210℃ according to increasing in roasting temperature and time. Conclusion : These results suggest that the ginkgo nut with heat treatment could be used in food materials and medicines for decreasing cyanide content as well as for increasing antioxidant compound content.

Background : F. fomentarius extracts have been recently reported to process immune-stimulatory and anti-inflammatory effects. In this study, we evaluated the anti-mutagenic effect of F. fomentarius ethanol extracts and the effective chemical components from the extract were analyzed by LC-Q-TOF. Methods and Results : F. fomentarius was extracted with 70% ethanol yielding a crude extract 6.8%. The crude extract was fractionated sequentially to diethyl ether, chloroform, dichloromethane, butanol and water with a yield of 43.9%, 2.958%, 6.8%, 21.6% and 25.5.%, respectively. The anti-mutagenic effect of F. fomentarius extract and its fractions was tested in Ames test by two type of Salmonella typhimurium (TA98 and TA100). Among the five fractions, diethyl ether has shown the highest and significant anti-mutagenic effect (98.3%, at 3,000 ㎍/plate concentration). Moreover, we investigated the chemical constituents of the extract using UPLC-Q-TOF. A total of 10 compounds such as flavonoids (velutin, 3, 4′,5-Trihydroxy-3′,7-dimethoxyflavanone) and fatty acids (γ-linoleic acid, stearic acid) and deterpenoid (kirenol) were tentatively identified with an accurate mass within 10 ppm mass error. Also, flavonoids and fatty acids were detected with higher rate than other compounds based on obtained chromatograms. Conclusion : We demonstrated that F. fomentarius extract and fractions have anti-mutagenic activity through Ames test. Furthermore, we will carry out isolation of each components from its fraction and use them to conduct additional anti-mutagenic test.

Background : Recently, many studies to seek for medicinal herb compounds from natural products have been attempted capable of being free from harmful side effects and reducing the economic burden. This study was conducted to investigate whether Morus alba L.(MAL) water extracts has a biological safety, and an inhibitory potential against the mutagenicity induced by cigarette smoke condensates(CSC). Methods and Results : MAL was extracted with 70% ethanol and the yield of the extract was 35.1%. The 70% ethanol MAL extract was fractionated sequentially by diethylether, chloroform, dichloromethane, and water, respectively. Crude MAL 70% ethanol extract itself and its solvent fractions did not show any mutagenic effect up to 1 mg/plate toward Salmonella typhimurium TA 98 with or without the microsomal S-9 mixture of liver metabolic activations. On the other hand, the crude MAL extract showed an inhibitory activity against the mutagenicity of CSC with S-9 mixture. Diethyl ether layer among five solvent fractions showed the highest inhibitory activity at the same dose. The inhibitory activity of diethyl ether layer was also increased dose-dependently and the inhibitory rate was about 97.1% at the concentration of 1 mg/plate. Conclusion : In this study, we concluded that all of the crude MAL 70% ethanol extract and its solvent layers are potentially safe for mutagenicity and the diethyl ether layer among the crude MAL 70% ethanol extract has an inhibitory effect against the mutagenicity of CSC.

본 연구의 첫 번째 목적은 당구 경기력에 영향을 미치는 심리적 요인을 탐색하는 것이다. 두 번째 목적은 탐색된 하위요인의 속성을 명확히 측정할 수 있는 당구 심리기술 검사지를 개발하는 것이다. 세 번째 목적은 개발된 당구 심리기술 검사지의 타당성을 검증하는 것이다. 50명의 국내 정상급 당구선수들을 대상으로 개방형 질문지와 면담을 통해 자료를 수집하고 귀납적 내용 범주분석 방법으로 분석하였다. 전국 당구선수 372명(표본 A 186명, 표본 B 186명)을 대상으로 표본 A 자료를 바탕으로 문항분석, 신뢰도 분석, 탐색적 요인분석, 표본 B 자료를 통해 확인적 요인분석을 실시하였다. 또한 수렴타당도, 변별타당도, 예측타당도, 구인동등성 검증, 잠재평균 비교분석을 통해 당구 심리기술 검사지의 타당성을 확인하였다. 이에 따른 연구결과는 다음과 같다. 첫째, 당구 경기력에 영향을 미치는 요인은 자신감, 불안조절, 주의집중, 심상, 목표설정, 행동루틴, 환경탄력성의 7가지 요인으로 나타났다. 둘째, 당구 심리기술 검사지의 27문항은 7가지 하위요인의 속성을 명확히 측정할 수 있는 문항으로 확인되었다. 셋째, 당구 심리기술 검사지는 타당성이 확보되어 신빙성 있는 측정도구임을 입증하였다.