• 한국동물위생학회지
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• 제17권2호
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• pp.95-113
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• 1994

To establish an effective diagnostic measure for detection of the antibodies against Actinobacillus pleuropneumoniae, the methods for tube agglutination test (TAT), plate agglutination test (PAT), micro-agglutination test(MAT) and agar-gel immunodiffusion test(ID) were improved and standarized, and the comparative studies were carried out. The results obtained through the experiments were summarized as follows. 1. The rabbit hyperimmune sera to reference serotypes 1 to 6 were cross-tested with TAT, PAT, MAT and ID. In the homologous systems, the range of antibody titers in TAT was 80 to 640, showing the cross-reaction in serotypes 3, 4, 5 and 6. The range of antibody titers in PAT was 4 to 64, showing the cross-reaction in serotypes 3, 4, 5 and 6. In ID, the range of antigen titers was 8 to 32, and cross-reaction was observed in serotype 5. 2. The optimal concentration of antigen in PAT and MAT were 100mg /ml and 1.25mg /ml respectively. The most sensitive reaction in MAT was observed in 52$^{\circ}C$ for 18hrs. 3. In ID, the most promising antigen and the buffer for agar-gel were EDTA-treated antigen and 0.05M tris buffer (pH 7.2), respectively. 4. By the tests for 200 swine sera, it was found that the frequency of positive reaction were 203 in TAT, 240 in PAT and 163 in ID. 5. When compared the titers of TAT with those of MAT for 200 swine sera, MAT showed the higher titer than TAT being increased by relative correlation. Int was found that the titer for positive readings were 20 in TAT and 40 in MAT. 6. when compared the results of ID with those of TAT for 200 swine sera, all sera with TAT titer under 10 were negative in ID. Of the sera with TAT titer 20 and 40, 55.1% nd 91.8% were positive in ID, respectively. All sera with TAT titer above 80 were positive in ID. In comparison of ID and MAT, all sera with MAT titer under 20 were negative in ID. Of the sera with MAT titer 40 and 80, 24.7% and 93.9% were positive in ID, respectively. All sera with MAT titer over 160 showed positive in ID. 7. In conclusion, the established MAT showed high sensitivity but low specificity, wherease ID revealed low sensitivity but high specificity.

• Bulletin of the Korean Chemical Society
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• 제27권5호
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• pp.672-678
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• 2006

A new approach to fabricate an enzyme electrode was described based on the immobilization of horseradish peroxidase (HRP) on dithiobis-N-succinimidyl propionate (DTSP) self-assembled monolayer (SAM) formed on gold-nanoparticles (Au-NPs) which were electrochemically deposited onto glassy carbon electrode (GCE) surface. The overall surface area and average size of Au-NPs could be controlled by varying deposition time and were examined by Field Emission-Scanning Electron Microscope (FE-SEM). The $O_2$ reduction capability of the surface demonstrated that Au-NPs were thermodynamically stable enough to stay on GCE surface. The immobilized HRP electrode based on Au-NPs/GCE presented faster, more stable and sensitive amperometric response in the reduction of hydrogen peroxide than a HRP immobilized on DTSP/gold plate electrode not containing Au-NPs. The effects of operating potential, mediator concentration, and pH of buffer electrolyte solution on the performance of the HRP biosensor were investigated. In the optimized experimental conditions, the HRP immobilized GCE incorporating smaller-sized Au-NPs showed higher electrocatalytic activity due to the high surface area to volume ratio of Au-NPs in the biosensor. The HRP electrode showed a linear response to $H_2O_2$ in the concentration range of 1.4 $\mu$M-3.1 mM. The apparent Michaelis-Menten constant ($K _M\; ^{app}$) determined for the immobilized HRP electrodes showed a trend to be decreased by decreasing size of Au-NPs electrodeposited onto GCE.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2001년도 추계학술발표대회
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• pp.918-922
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• 2001

In a previous study, we have isolated a number of lactobacilli from Korean women, and one of them (KLB46) was identified as Lactobacillus crispatus by 16S rRNA gene sequencing. For the ecological treatment of bacterial vaginosis (BV) cell suspension of L. crispatus KLB46 was instillated into BV patients. L. crispatus KLB46 was found to persist for several days in cell suspension with no nutrients. In this study, in order to assess the influence of starvation on physiological activity, we compared the viability and culturability of KLB46 following suspension in various buffer solutions. A pair of in situ fluorescent dye was used to assess viability (i.e. membrane integrity) and the culturability was examined by plate count assay. A rapid epifluorescence staining method using the LIVE/DEAD Bacterial Viability Kit $(BacLight^{TM})$ was applied to estimate both viable and total counts of bacteria in cell suspension. $BacLight^{TM}$ is composed of two nucleic acid-binding stains ($SYTO\;9^{TM}$ and propidium iodide). $SYTO\;9^{TM}$ penetrates all bacterial membranes and stains the cells green while propidium iodide only penetrates cells with damaged membranes, therefore the combination of the two stains produces red fluorescing cells. Optimal staining conditions for $BacLight^{TM}$ were found to be with 0.0835M $SYTO\;9^{TM}$ and 0.05M propidium iodide for 15 min incubation at room temperature in dark. When cells were microscopically examined during 140 hours of starvation, the culturability decreased markedly while the viability remained relatively constant, which suggests that large fraction of KLB46 cells became viable but non-culturable (VBNC) upon starvation.

• Applied Biological Chemistry
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• 제36권1호
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• pp.7-10
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• 1993

ELISA법을 zearalenone 생성균주 검색에 응용하였다. 먼저 zearalenone에 대한 항체를 500배 희석한 후 microtiter well에 $125\;{\mu}l$씩 주입하여 $40^{\circ}C$에서 overnight시켜 coating하고, 시료용액과 enzyme을 $37^{\circ}C$에서 30분간 반응시켰다. 배양후 washing buffer로 6회 세척한 다음 plate에 2,2'-azino-di-3-ethyl-benzthiazoline sulfonic acid(ABTS) 용액을 $100\;{\mu}l$씩 첨가하여 15분간 발색시킨 다음 반응 정지액 $100\;{\mu}l$씩을 가해 반응을 정지시키고 ELISA Reader로서 흡광도(410 nm)를 측정하였다. 그 결과 zearalenone 생성이 확인된 19 균주 중 분리균 R-5, C-46 및 S-134가 50 ng/ml 이상의 zearalenone을 생성하였다.

• Composites Research
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• 제30권1호
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• pp.21-25
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• 2017

본 연구에서는 일방향 생분해성 유리섬유(BGF)와 친환경 생분해성 수지인 폴리락트산(PLA)을 이용하여 골절치료용 복합재료 고정판을 제작하고 체액 노출에 따른 고정판의 성능 변화를 확인하고자 $50.0^{\circ}C$ 온도조건으로 설정된 인산완충식염수(PBS)에 제작된 생분해성 고정판을 0~3주 동안 노출시켜 질량 변화를 측정하고 4점 굽힘 실험을 수행하였다. 굽힘 강성, 수분 흡수율, 그리고 질량 감소율과 같은 기계적 특성 변화를 파악하였으며 실험 결과로부터 노출 기간이 증가함에 따라 고정판을 구성하고 있는 생분해성 재료들의 손실로 인해 기계적 물성이 서서히 저하되는 경향을 보이는 것을 확인하였다.

• Journal of Oral Medicine and Pain
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• 제39권3호
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• pp.90-95
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• 2014

Purpose: To investigate viscosity and wettability of hyaluronic acid (HA) solutions according to supplementation of lysozyme and/or peroxidase, and different ionic strength and pH conditions. Methods: Solutions containing HA were prepared using distilled deionized water (DDW) and simulated salivary buffer (SSB) in different conditions. Different concentrations of hen egg-white lysozyme and bovine lactoperoxidase was added into HA solutions. HA solutions with antimicrobials in different ionic strength and pH conditions were prepared. Viscosity was measured using cone-and-plate digital viscometer at six different shear rates and wettability on acrylic resin and Co-Cr alloy was determined by contact angle. Results: The viscosity values of HA dissolved in DDW were decreased in order of HA, HA containing lysozyme, HA containing peroxidase, and HA containing lysozyme and peroxidase. The viscosity values for HA in DDW were decreased as the concentration of lysozyme and/or peroxidase increased. However, the viscosity values for HA in SSB showed no significant changes according to the concentration of lysozyme and/or peroxidase. The viscosity values of HA solutions were inversely proportional to ionic strength and pH. The contact angle of HA solutions showed no significant differences according to tested surface materials, addition of lysozyme and/or peroxidase, and different ionic strength and pH conditions. Contact angles on acrylic resin by HA solutions in all tested conditions were much higher than those by human saliva. Conclusions: The rheological properties of HA supplemented with lysozyme and/or peroxidase in different ionic strength and pH conditions were objectively confirmed, indicating the possibility of HA with lysozyme and/or peroxidase as main components in the development of effective saliva substitutes.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 추계학술대회
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• pp.249-254
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• 1997

ABA-type block copolymers composed of poly(L-leucine)(PLL) as the A component and poly(ethylene glycol)(PEG) as the B component were synthesized by ring-opening polymerization of L-leucine N-carboxyanhydride initiated by primary amino group located at both ends of PEG chain. A silver sulfadiazine(AgSD)-impregnated wound dressing of sponge-type was prepared by the lyophilization method. Morphological structure of this wound dressing obtained by scanning electron microscopy(SEM) was composed of a dense skin layer and a macroporous inner sponge layer. Equilibrium water content(EWC) of wound dressing was above 10%. It increased with an increased of PEO content in the block copolymer due to the hydrophilicity of PEO. AgSD release from AgSD- impregnated wound dressing in PBS buffer(pH=7.4) was dependent on PEG composition in the block copolymer. Therefore, EWC and release of AgSD can be control by PEG composition. Antibacterial capacity of AgSD-impregnated wound dressing was examined in agar plate against Pseudmonas aeruginosa and Stapplococus aruous. Cytotoxicity of the wound dressing was evaluated by studing mouse skin fibroblast(L929). From the behavior of antimicrobial releasing and the investigation of the suppression of bacterial proliferation, it was supposed that the wound dressing containing antibiotics could protect the wound surfaces from bacterial invasion to suppress the bacterial proliferation effectively. In cytotoxicity observation, cellular damage was reduced by the control led released of AgSD from the LEL sponge matrix of AgSD-medicated wound dressing. In vivo test, granulous tissue formation and wound contraction or the AgSD and DHEA impregnated wound dressing were aster than any other groups.

• Journal of Microbiology and Biotechnology
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• 제31권7호
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• pp.999-1010
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• 2021

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the environment. They are highly toxigenic and carcinogenic. Probiotic bacteria isolated from fermented foods were tested to check their ability to degrade and/or detoxify PAHs. Five probiotic bacteria with distinct morphologies were isolated from a mixture of 26 fermented foods co-cultured with benzo(a)pyrene (BaP) containing Bushnell Haas minimal broth. Among them, B. velezensis (PMC10) significantly reduced the abundance of BaP in the broth. PMC10 completely degraded BaP presented at a lower concentration in broth culture. B. velezensis also showed a clear zone of degradation on a BaP-coated Bushnell Haas agar plate. Gene expression profiling showed significant increases of PAH ring-hydroxylating dioxygenases and 4-hydroxybenzoate 3-monooxygenase genes in B. velezensis in response to BaP treatment. In addtion, both live and heat-killed B. velezensis removed BaP and naphthalene (Nap) from phosphate buffer solution. Live B. velezensis did not show any cytotoxicity to macrophage or human dermal fibroblast cells. Live-cell and cell-free supernatant of B. velezensis showed potential anti-inflammatory effects. Cell-free supernatant and extract of B. velezensis also showed free radical scavenging effects. These results highlight the prospective ability of B. velezensis to biodegrade and remove toxic PAHs from the human body and suggest that the biodegradation of BaP might be regulated by ring-hydroxylating dioxygenase-initiated metabolic pathway.

• 한국초전도ㆍ저온공학회논문지
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• 제8권1호
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• pp.9-14
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• 2006

Sample preparation plays a critical role in microstructure analysis using TEM. Although TEM specimen has been usually prepared by jet-polishing or Ar-ion beam milling technique. these methods could not be applied to YBCO CC which is composed of IBAD or RABiTS substrates, several buffet layers, and YBCO superconducting layer because of big difference in mechanical strengths between the metallic phase and oxide phases. To obtain useful cross-sectional information such as interface between the phases or second phases in YBCO CC, it is prerequisite to secure the large area of thin section in the cross-sectional direction. The superconducting layer or the buffer layers are relatively weak and fragile compared to the metallic substrate such as Ni-5wt%W RABiTS of Hastelloy-based IBAD, and preferential removal of weak ceramic phases during polishing steps makes specimen preparation almost impossible. Tripod polisher and small jig were home-made and employed to sample preparation. The polishing angle was maintained <$1^{\circ}$ throughout the polishing steps using 2 micrometers attached to the tripod plate. TEM specimens with large and thin area could be secured and used for RABiTS/IBAD substrate analyses. In some cases, additional Ar-beam ion milling with low beam current and impinging angle was used for less than 30 sec. to remove debris or polishing media attacked to the specimens.

• 한국항행학회논문지
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• 제28권4호
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• pp.544-551
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• 2024

본 연구에서는 도금 공정 시뮬레이션에 필요한 전기화학적 분극 데이터와 도금 조건 시뮬레이션 및 도금층의 특성 평가에 대해 다루었다. Ni과 Cu의 동전위 분극 분석 및 정전류 분극 시험을 통해 얻은 전기화학적 분극 데이터는 도금액의 유동 조건에 따른 과전압 분포 변화를 관찰하는 데 사용되었다. 도금 조건 시뮬레이션에서는 랙 핀의 접점 위치와 개수가 도금 품질에 미치는 영향을 분석하기 위해 다양한 변수 하에서 전류 밀도 분포 및 도금 두께 분포를 평가하였다. 양극 형상, 극간 거리, 보조 양극 배치, 피도금체 간격 변화 등의 변수에 따른 시뮬레이션 결과를 통해 도금 두께 편차를 개선할 수 있는 방안을 모색하였다. 또한, 도금층의 특성 평가는 버퍼레이어 형성 유무에 따른 도금층의 두께, 밀착성 및 박리 여부를 분석하였다. 시뮬레이션을 통해 도금 공정의 효율성과 품질 향상을 위한 중요한 기초 데이터로 활용될 수 있다.