• Mass Spectrometry Letters
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• 제6권1호
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• pp.13-16
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• 2015

This study demonstrated the stabilizing role of a cyclodextrin on Keggin $[PW_{12}O_{40}]^{3-}$ via hydrogen bonding complexation unveiled by ESI-MS. The distinctive fragmentation pathways of the $\{PW_{12}\}/{\gamma}$-CD complexes from that of discrete $[PW_{12}O_{40}]^{3-}$ showed that the so-called "weak" non-covalent interactions can effectively change the dissociation chemistry of POM in the gas phase. The influence of different types of solvents and organic additives such as ${\gamma}$-CD on the stability of Keggin $[PW_{12}O_{40}]^{3-}$ was also addressed firstly by ESI-MS.

• 대한수의학회지
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• 제36권2호
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• pp.371-378
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• 1996

Three and 2 strains of E coli O157 were isolated from fecal materials of cattle (390) and pigs (420) in Korea, respectively. One strain of O157:H7 isolated from cattle and 2 strains of O157:H7 isolated from pigs were identified as verotoxin-1 (VT-1) produing strains and 2 strains (O157:H7 and O157:H-) isolated from cattle were identified as verotoxin-2 (VT-2) producing strains by neutralization test on HeLa and Vero cells. Culture supernatants of the isolates were cytotoxic to HeLa and Vero cells. The levels of cytotoxin produced by isolates were $10^2{\sim}10^4$ cytotoxic dose($CD_{50}$)/ml. Also, VT-2-converting bacteriophage was isolated from KSC109 strain which had been isolated from cattle. Molecular weight of the phage DNA was determined as approximately 45 Kb in 0.8% agarose gel electrophoresis, and morphology of the phage stained with phosphotungstic acid was observed by transmissible electron microscopy.

• Journal of Dairy Science and Biotechnology
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• 제33권4호
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• pp.237-245
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• 2015

본 연구는 원유로부터 면역효능이 우수한 젖산균 Streptococcus macedonicus LC743을 분리하였고, 이 균으로 제조한 모짜렐라 치즈와 상업균주로 제조한 모짜렐라 치즈에 대해 이화학적 특성을 비교시험하였다. S. macedonicus LC743을 이용한 치즈의 일반성분 결과, 수분 53.16%, 단백질 26.42%, 지방 20.52%였다. S. macedonicus LC743을 이용한 치즈의 질소화합물 중 수용성 질소는 0.384%, 비단백태질소 0.051%, 아미노태질소는 0.060 Nmg/g으로서 상업균주를 이용한 치즈에 비해 수용성 질소 및 아미노태질소의 함량은 적은 반면, 비단백태 질소 함량은 높았다. 각 치즈에 존재하는 유기산 분석 결과 상업균주로 제조한 치즈가 809.80 mg/mL로서 가장 많은 함량을 나타낸 반면, S. macedonicus LC743으로 제조한 치즈는 668.09 mg/mL로 가장 낮은 함량을 보였다. S. macedonicus LC743을 이용한 치즈의 총 아미노산은 Ctysteine을 제외하고는 모든 아미노산에서 상업균주를 이용한 치즈에 비해 높은 함량을 차지하였다. S. macedonicus LC743 균주로 제조된 모짜렐라 치즈는 상업용 스타터로 제조된 모짜렐라 치즈, 시중 제품 및 외국제품에 비해 면역분비능이 높은 것으로 나타났으며, S. macedonicus LC743 균주를 상업균주와 혼합하여도 면역활성능이 우수한 것으로 나타났다.

• 한국수소및신에너지학회논문집
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• 제16권2호
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• pp.103-110
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• 2005

Proton conducting solid polymer electrolyte (SPE) membranes have been used in many energy technological applications such as water electolysis, fuel cells, redox-flow battery, and other electrochemical devices. The availability of stable membranes with good electrochemical characteristics as proton conductivity at high temperatures above 80 $^{\circ}C$ and low cost are very important for its applications. However, the presently available perfluorinated ionomers are not applicable because of high manufacturing cost and high temperature use to the decrease in the proton conductivity and mechanical strength. In order to make up for the weak points, the block copolymer (BPSf) of polysulfone and poly (phenylene sulfide sulfone) were synthesized and sulfonated. The electrolyte membranes were prepared with phosphotungstic acid (HPA)/sulfonated BPSf via solution blending. This study would be desirable to investigate the interaction between the HPA and sulfonated polysulfone. The results showed that the characteristics of SPSf/HPA blend membrane was a better than Nafion at high temperature, 100 $^{\circ}C$. These membranes proved to have a high proton conductivity, $6.29{\times}10-2$ S/cm, a water content, 23.9%, and a ion exchange capacity, 1.97 meq./g dry membrane. Moreover, some of the membranes kept their high thermal and mechanical stability.

• 한국식품과학회지
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• 제25권5호
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• pp.510-516
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• 1993

이 실험에서 U.F.를 이용하여 제조한 치즈베이스의 숙성을 촉진시키기 위하여 시판되는 단백질 및 지방가수분해효소를 치즈베이스 slurries에 첨가하여 이화학적 특성을 조사하였다. 치즈베이스 slurries에서 TCA 가용성 질소화합물의 생성은 숙성 첫날에 급격한 증가를 보였고 그 후에는 완만했으며 체다치즈 slurries에서 보다 낮았다. PTA 가용성 아미노태 질소화합물의 생성도 TCA 가용성 질소화합물의 경향과 유사했지만 소량 생성되었다. 전기영동에서 치즈베이스 slurries와 체다치즈 slurries의 카제인이 모두 분해되었으나, 치즈베이스 slurries에서는 유청단백질이 거의 분해되지 않았다. 아미노산 생성에서 치즈베이스 slurries는 체다치즈 slurries에서 보다 매우 적은 함량을 보였다. 단쇄 유리지방산의 생성에서 치즈베이스 slurries는 체다치즈 slurries에서와 유사한 증가를 보였으며, 체다치즈의 자연숙성에서와 유사한 특이성을 나타내었다. 이 실험의 결과, 치즈베이스의 숙성 촉진을 위하여 효소첨가는 효과가 있는 것으로 나타났다.

• The Korean Journal of Physiology and Pharmacology
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• 제16권6호
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• pp.423-429
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• 2012

Brain ischemia leads to overstimulation of N-methyl-D-aspartate (NMDA) receptors, referred as excitotoxicity, which mediates neuronal cell death. However, less attention has been paid to changes in synaptic activity and morphology that could have an important impact on cell function and survival following ischemic insult. In this study, we investigated the effects of reperfusion after oxygen/glucose deprivation (OGD) not only upon neuronal cell death, but also on ultrastructural and biochemical characteristics of postsynaptic density (PSD) protein, in the stratum lucidum of the CA3 area in organotypic hippocampal slice cultures. After OGD/reperfusion, neurons were found to be damaged; the organelles such as mitochondria, endoplasmic reticulum, dendrites, and synaptic terminals were swollen; and the PSD became thicker and irregular. Ethanolic phosphotungstic acid staining showed that the density of PSD was significantly decreased, and the thickness and length of the PSD were significantly increased in the OGD/reperfusion group compared to the control. The levels of PSD proteins, including PSD-95, NMDA receptor 1, NMDA receptor 2B, and calcium/calmodulin-dependent protein kinase II, were significantly decreased following OGD/reperfusion. These results suggest that OGD/reperfusion induces significant modifications to PSDs in the CA3 area of organotypic hippocampal slice cultures, both morphologically and biochemically, and this may contribute to neuronal cell death and synaptic dysfunction after OGD/reperfusion.

• Journal of Ginseng Research
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• 제48권4호
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• pp.366-372
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• 2024

Background: The biological activity and pharmacological effects of rare ginsenosides have been proven to be superior to those of the major ginsenosides, but they are rarely found in ginseng. Methods: Ginsenoside Rb1 was chemically transformed with the involvement of methanol molecules by a synthesized heterogeneous catalyst 12-HPW@MeSi, which was obtained by the immobilization of 12-phosphotungstic acid on a mesoporous silica framework. High-performance liquid chromatography coupled with mass spectrometry was used to identify the transformation products. Results: A total of 18 transformation products were obtained and identified. Methanol was found to be involved in the formation of 8 products formed by the addition of methanol molecules to the C-24 (25), C-20 (21) or C-20 (22) double bonds of the aglycone. The transformation pathways of ginsenoside Rb1 involved deglycosylation, addition, elimination, cycloaddition, and epimerization reactions. These pathways could be elucidated in terms of the stability of the generated carbenium ion. In addition, 12-HPW@MeSi was able to maintain a 60.5% conversion rate of Rb1 after 5 cycles. Conclusion: Tandem and high-resolution mass spectrometry analysis allowed rapid and accurate identification of the transformation products through the characteristic fragment ions and neutral loss. Rare ginsenosides with methoxyl groups grafted at the C-25 and C-20 positions were obtained for the first time by chemical transformation using the composite catalyst 12-HPW@MeSi, which also enabled cyclic heterogeneous transformation and facile centrifugal separation of ginsenosides. This work provides an efficient and recyclable strategy for the preparation of rare ginsenosides with the involvement of organic molecules.

• Applied Microscopy
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• 제34권1호
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• pp.1-11
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• 2004

상처회복과정은 염증, 재상피화, 그리고 기질의 재형성등을 포함한 포괄적인 생물학적 반응이다. 생물학적 분류체계에서, 회복능력은 매우 다양한데, 일반적으로 하등동물이 고등동물에 비교해 단순하며 뛰어난 것으로 알려져 있다. 따라서, 하등동물들을 이용한 실험모델은 상처회복과 치유의 기작을 연구하는데 자주 이용되고 있다. 양서류를 이용한 피부 상처회복과정 동안의 조직화학적 특성들을 규명하기 위하여 한국산 무당개구리(Bombina orientalis)를 이용하였다. 1일, 10일 그리고 16일의 조직에서 점액물질이 활발하게 분비되는 것을 확인하였으며, PAS (periodic acid shiff)와 Alcian blue (pH 2.5) 반응에 강하게 염색되었다. PTAH(phosphotungstic acid hematoxylin) 염색을 통하여 상처 후 10일 조직에서 상처주변의 진피층에서 콜라겐의 합성이 증가하는 것을 확인하였다. 또한, 세포의 유사분열의 시점을 확인하기 위한 MG-P (methyl green pyronin)염색에서 초기에는 3시간과 6시간에 강한 염색반응을 관찰하였고, 이는 23일과 27일 조직에서도 동일한 패턴으로 이어졌다.