• Journal of Plant Biotechnology
• /
• v.35 no.3
• /
• pp.235-243
• /
• 2008

Here we describe a procedure for Chinese cabbage protoplast culture and effects of various treatments. Chinese cabbage protoplasts were isolated from different parts of young seedlings as using an enzyme mixture, of which yield was maximized in seven hours around after digestion. The highest rate of initial cell division followed by micro-callus formation was obtained in the medium with 1.0 mg/L 2,4-D, 0.5 mg/L NAA, and 1.0 mg/L BA when the cotyledon-derived protoplasts were cultured. Initiation of cell division and micro-callus proliferation significantly depended upon Chinese cabbage genotype under a same culture circumstances. The micro-calli developed from cotyledon tissue of Norang-Bom cultivar successfully grew toward callus colonies on the solidified medium with 0.2 mg/L zeatin and 0.1 mM spermidine. The callus colonies generated de novo shoots at the maximum frequency of 4.3% on the medium with 5.0 mg/L BA and 1.0 mg/L NM. Our results might be helpful for further studies to enhance the regeneration efficiency in Chinese cabbage protoplast culture.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.11 no.3
• /
• pp.81-86
• /
• 1982

Ginseng saponins separated from Panax ginseng C.A. Meyer were analyzed by high-performance liquid chromatography using a carbohydrate analysis column. The effect on the resolution and retention time of each ginsenosides, as well as the addition effect of n-butanol on a acetonitrile/water system, was examined using various proportions of acetonitrile/water system (80/20-94/6) which have been used with typical solvent of carbohydrate analysis column. The retention time of each ginsenosides was greatly affected by the compositions and mixture proportions of the mobile phase and also markedly increased as the proprotion of acetonitrile in mobile phase increased. It was proved that acetonitrile/water system (80/20) and acetonitrile/water/n-butanol system (86/14/10) were very effective mobile phases for diol and triol sapoin analyses, respectively. According to the result obtained by this method, the PT/PD ratios of white and red ginseng saponins were 0.401 % and 0.561 %, respectively. Red ginseng increased PT/PD ratio, compared with white ginseng. This is attributed to the change of saponin pattern by processing method and the change of PT/PD ratio would greatly influence on the biochemical and pharmacological effects of ginseng and its products.

• Journal of the Korean Electrochemical Society
• /
• v.16 no.2
• /
• pp.91-97
• /
• 2013

Solid polymer electrolyte films are prepared by ultraviolet radiation in the mixtures of an ionic liquid salt (1-ethyl-3-methylimidazolium tetrafluoroborate, $EMIBF_4$) and solvent (acetonitrile (ACN) or propylene carbonate(PC)), and an oligomer (poly(ethylene glycol)diacrylate, PEGDA, 45-60 wt.%). Electrochemical properties of activated carbon supercapacitors adopting the solid polymer electrolyte films as a separator are also examined by cyclic voltammetry and impedance measurement techniques. As a result, the supercapacitor adopting the PEGDA as much as 45 wt.% exhibits a superior capacitance of $46Fg^{-1}$ at $20mVs^{-1}$. It seems that this is due to fast kinetics of ion conduction by sufficient film flexibility, which can be allowed by comparatively weak ultraviolet curing of small anount of the PEGDA.

• Journal of Life Science
• /
• v.20 no.12
• /
• pp.1882-1888
• /
• 2010

To develop probiotics, a kind of Lactobacillus sp. was isolated from infant feces. The bacterium was identified as Lactobacillus rhamnosus through 16S rDNA sequence analysis. The strain was a facultative anaerobe which grew better in aerobic conditions. The bacterium lowered the pH of the culture solution down to 2.4 during 48 hr in the MRS medium. The strain inhibited the growth of 6 pathogens - S. aureus, L. monocytogens, S. typhimurium, E. coli O-157, V. parahaemolyticus and P. aeruginosa. When the Lactobacillus were fed to chickens, along with commercial feed, for one month, amounts of $H_2S$ and $NH_3$ in the feces of the chicken decreased to 50% and 70%, respectively, compared to those of control group chickens. Amounts of other bad smells such as $(CH_3)SH$, $(CH_3)_2S$ and $(CH_3)_2S_2$ were not much different in the Lactobacillus-fed chickens compared to the control group. On the other hand, egg weights of the chickens fed Lactobacillus were higher by about $5{\pm}1\;g$ than those in the control group.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.20 no.4
• /
• pp.314-321
• /
• 2000

A gap between a $Al_2O_3/Fe$ thermite and lower head vessel is formed in the lower-plenum arrested vessel attack(LAVA) experiment which is the 1st phase study of simulation of naturally arrested vessel attack in vessel(SONATA-IV). The gap measurement using a conventional ultrasonic method would be lack of a reliability due to the structure complexity and the metallurgical grain size change of the lower head HAZ occurred by a thermite $Al_2O_3/Fe$ melt or a $Al_2O_3$ melt at $2300^{\circ}C$. The grain echoes having false signals and lower S/N ratio signals are detected due to a multiple scattering, a mode conversion and an attenuation of a ultrasonic resulted from at the interface of increased grain size zone. In this test, the signals pattern was classified to understand the behavior of the ultrasonic in a multi-layer specimen of solid-liquid-solid of assuming that the thermite and the lower head vessel is immersed. The polarity threshold algorithm of frequency diversity gives us the enhancement about 6dB of the ratio S/N.

• Journal of the Korean Society of Groundwater Environment
• /
• v.1 no.2
• /
• pp.100-104
• /
• 1994

The rock matrix diffusion provides a retarding mechanism for sorbing and especially non-sorbing radionuclides. It has to be verified not only theoretically and experimentally but also from natural phenomena, before the mechanism can be incorporated fully into transport codes. The natural analogue studies, such as the concentration variation of radionuclides in profiles perpendicular to fluid-conducting fractures and to intrusive contact zones, have been believed to provide a validation. In thermal alteration zones of Naeduckri granite intruded by a pegmatite, large alkali and alkaline earth elements such as K, Rb, Sr, and Ba were moderately migrated during thermal alteration. Li, V. and Nb were also migrated about 9cm in width from the contact between the granite and the pegmatite. The concentration variation of these elements in thermally altered zones seems to be resulted from the local migration due to the re-equilibration among the elements released from the breakdown of primary minerals in the granite. Most of these natural analogue studies simply show only the concentration variation of elements without detailed informations on the diffusion time and other important data fir interpreting the behaviour of radionuclides, because of the absence of appropriate minerals for age data. Despite this problem, natural analogue studies will be needed for transport models of radionuclides in safety assessment.

• Korean Journal of Microbiology
• /
• v.47 no.1
• /
• pp.74-80
• /
• 2011

Bacteriocin-producing lactic acid bacterium having antagonistic activity against Bacillus cereus, was isolated from Kimchi. The selected strain was identified as Lactococcus lactis by the Bergey's manual and 16S rDNA analysis, and named as L. lactis ET45. The bacteriocin was stable in the pH range 3.0-11.0. The bacteriocin was active over a wide temperature range from $40^{\circ}C$ to $121^{\circ}C$. Optimal culture condition for producing bacteriocin was obtained by growing the cells on MRS medium at pH 7.5 and $30^{\circ}C$ for 18 h. Antibacterial activity of the bacteriocin was completely disappeared by proteinase K, and this means that bacteriocin is a proteinous substance. The molecular weight of bacteriocin was estimated to be about 4.5 kDa by tricine sodium dodecyl sulfate polyacryamide gel electrophoresis (TSDS-PAGE).

• Korean Journal of Microbiology
• /
• v.46 no.1
• /
• pp.9-14
• /
• 2010

In this study, lactic acid bacteria with high angiotensin converting enzyme inhibitor activity were isolated from Korean fermented food, such as kimchi and salted seafood. The strain HLJ59, isolated from salted shrimp showed the highest angiotensin converting enzyme inhibitor activity in DeMan Rogosa Sharpe broth. Optimum growth temperature of Lactobacillus brevis HLJ59 was at $34^{\circ}C$. Acid treatment at pH 3.0 for 1.5 h decreased cell viability from $9.9{\times}10^8$ CFU/ml to $3.11{\times}10^4$ CFU/ml. The bile extract concentration of 0.3%, 0.5%, and 1.0% in MRS broth did not inhibit the growth of HLJ59. Isolated strain HLJ59 showed more sensibility to amikacin, gentamycin, neomycin, streptomycin, kanamycin, cefmetazole, cephalothin, ampicillin, ticarcillin, sulbactam+ampicillin, amoxicillin+clavulanic acid (AMC), tetracycline, and sulfamethoxazole+trime thoprim (SXT) as compare to other 7 different antibiotics. However, it showed more resistance to cefoxatin, ceftnaxone, penicillin, ciprofloxacin, nalidixic acid, lincomycin, and chloramphenicol.

• Korean Journal of Microbiology
• /
• v.49 no.1
• /
• pp.83-89
• /
• 2013

A bacterium, isolated from a vegetable field in a plastic film house and named strain CY6 was capable of biodegrading chlorpyrifos (CP). Based on the phenotypic features and the phylogenetic similarity of 16S rRNA gene sequences, strain CY6 was identified as a Naxibacter sp.. CP was utilized as the sole source of carbon and phosphorus by Naxibacter sp. CY6. We examined the role of this Naxibacter sp. in the degradation of other OP insecticides under liquid cultures. Parathion, methyl parathion, diazinon, cadusafos, and ethoprop could also be degraded by Naxibacter sp. CY6 when they are provided as the sole sources of carbon and phosphorus. Additionally, Naxibacter sp. CY6 ($10^8$ CFU/g) added to soil with CP (100 mg/kg) resulted in a higher degradation rate of approximately 90% than the rate obtained from uninoculated soils. These results highlight the potential of this bacterium to be used in the cleanup of contaminated pesticide soil.

• 한국신재생에너지학회:학술대회논문집
• /
• 2006.11a
• /
• pp.463-466
• /
• 2006

직접 알콜 연료전지는 액체인 알콜을 직접 연료전지에 공급하여 연소시킴으로써 높은 효율을 갖는 휴대용전원으로 주목받는 장치이다. 직접 알콜 연료전지에 담지체로 사용되는 탄소 소재는 넓은 표면적과 우수한 전기전도도를 가지고 있다는 장점 있으나 금속 촉매와의 상호작용이 약하여 촉매 활성에 영향을 주지 못한다. 산화물을 담지체로 사용할 경우 이러한 금속-담지체 간의 상호작용으로 인한 촉매활성 증가 및 입자성장 억제의 효과를 기대할 수 있다. 본 연구에서는, 안티몬 도핑된 주석산화물 (Sb-doped SnO2 : ATO nanoparticle)을 직접 메탄올 연료전지용 담지체어 적용하였으며 합성 과정은 다음과 같다. SnC14 5H2O SbC13, NaOH, HCl 수용액 혼합물을 삼구 플라스크에 넣고 $100^{\circ}C$ 온도에서 환류(reflux) 시킨 후 세척 및 건조하여 Air 분위기에서 열처리하였다. 합성된 산화물 수용액에 폴리올 방법으로 합성된 백금 콜로이드를 담지하였으며, 세척과 건조를 통하여 산화물에 담지된 백금 촉매를 촉매를 합성하였다. 촉매의 구조분석을 위해 XRD, TEM을 사용하였으며, 전극촉매로서의 활성을 평가하기 위해 cyclic voltammetry을 평가하였다. 본 연구에서는 백금의 담지량에 따른 Costripping voltammetry특성과 메탄올 및 에탄올 산화 반응 특성에 대하여, 탄소를 담지체로 사용한 Pt/C 촉매와 비교 평가하였다. 알콜 산화반응 평가결과, 주석산화물에 담지한 촉매가 탄소를 담지체로 사용한 촉매보다 우수한 활성을 나타내었으며 활성증가는 메탄올에 비해 에탄올 산화 반응의 경우 크게 증가하였다. 막과 비교해 보았다. $ZrO_2$ 입자는 전도성이며 동시에 친수성을 나타내기 때문에 상용 막에 비하여 함수율 및 수소이온 전도도가 우수하게 나타났다. 복합막의 이러한 물성은 $100^{\circ}C$이상의 고온에서 전해질 막 내의 물 관리를 용이하게 한다. 단위 전지 운전 온도 $130^{\circ}C$, 상대습도 37%의 운전 조건에서도 상당히 우수한 전지 성능을 보임에 따라 고온/저가습 조건에서 상용 Nafion 112 막보다 우수한 막 특성을 나타냄을 확인하였다.소/배후방사능비는 각각 $2.18{\pm}0.03,\;2.56{\pm}0.11,\;3.08{\pm}0.18,\;3.77{\pm}0.17,\;4.70{\pm}0.45$ 그리고 $5.59{\pm}0.40$이었고, $^{67}Ga$-citrate의 경우 2시간, 24시간, 48시간에 $3.06{\pm}0.84,\;4.12{\pm}0.54\;4.55{\pm}0.74 $이었다. 결론 : Transferrin에 $^{99m}Tc$을 이용한 방사성표지가 성공적으로 이루어졌고, $^{99m}Tc$-transferrin의 표지효율은 8시간까지 95% 이상의 안정된 방사성표지효율을 보였다. $^{99m}Tc$-transferrin을 이용한 감염영상을 성공적으로 얻을 수 있었으며, $^{67}Ga$-citrate 영상과 비교하여 더 빠른 시간 안에 우수한 영상을 얻을 수 있었다. 그러므로 $^{99m}Tc$<