• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XII)
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• pp.690-693
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• 2003

The antimicrobial effect of the Ginkgo biloba leaves extracts, Wood flavor and 1% sorbic for the total microorganics in beef examined by serial dilution method. As a result of using GLEA(T20), GLW80, Wood flavor and 1% sorbic acid by serial dilution method, it was revealed that wood flavor is most antibiotic. The decreased of wood flavor 82.80%, GLEA(T20) 73.44%, sorbic acid 66.33%, GLW80 64.36%, was compared with not treated.

• Biotechnology and Bioprocess Engineering:BBE
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• 제8권4호
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• pp.233-239
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• 2003

For the quantitative analysis of an unknown sample a calibration curve should be obtained, as analytical instruments give relative, rather than absolute measurements. Therefore, researchers should make standard samples with various known concentrations, measure each standard and the unknown sample, and then determine the concentration of the unknown by comparing the measured value to those of the standards. These procedures are tedious and time-consuming. Therefore, we developed a polymer based microfluidic device from polydimethylsiloxane, which integrates serial dilution and capillary electrophoresis functions in a single device. The integrated microchip can provide a one-step analytical tool, and thus replace the complex experimental procedures. Two plastic syringes, one containing a buffer solution and the other a standard solution, were connected to two inlet holes on a microchip, and pushed by a hydrodynamic force. The standard sample is serially diluted to various concentrations through the microfluidic networks. The diluted samples are sequentially introduced through microchannels by electro-osmotic force, and their laser-induced fluorescence signals measured by capillary electrophoresis. We demonstrate the integrated microchip performance by measuring the fluorescence signals of fluorescein at various concentrations. The calibration curve obtained from the electropherograms showed the expected linearity.

• 약학회지
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• 제40권6호
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• pp.653-658
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• 1996

As part of our search for less toxic antimicrobial agents from natural resources. rutin was isolated from Sophora japonica and then hydrolyzed to quercetin. Antimicrobial activity of quercetin was tested in vitro against five kinds of gram positive and ten kinds of gram negative bacteria by serial broth dilution method. Among fifteen kinds of bacteria tested, the antimicrobial activity of quercetin was the most potent against Proteus vulgaris showing minimal inhibitory concentration(MIC) of 125 ${\mu}$g/ml. To investigate the effect of antimicrobial combinations of quercetin with four kinds of antibiotics (ampicillin, cefazolin, oxytetracycline and chloramphenicol). the fractional inhibitory concentration index (FICI) was determined by checkerboard assay for each strain. The antimicrobial combinations of quercetin with four kinds of antibiotics resulted in synergism in one instance, additive effect in four instances, but no antagonism was observed.

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2004년도 춘계학술발표대회
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• pp.201-201
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• 2004

In this study we examined whether vitrified Hanwoo (Korean cattle) IVM/IVF/IVC blastocysts can survive in vitro/in vivo by a quick one-step dilution method and these embryos result in live births. Blastocysts produced in vitro were vitrified by serial exposure to glycerol (G) and/or ethylene glycol (EG) mixtures of 10% (v/v) G for 5 min, 10% G plus 20% EG (v/v) for 5 min, and 25% G plus 25% EG (v/v) for 30 see. (omitted)

• Fisheries and Aquatic Sciences
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• 제8권1호
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• pp.27-33
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• 2005

This is a subsequent study to our previous finding that Pacific oysters, Crassostrea gigas, gained a so-called upper plateau concentration, around 30,000 ng/g dry weight digestive gland for benzo(a)pyrene, showed reproductive behavior but produced their ensuing reproductive outputs damaged. A serial dilution of sediment elutriates from Jinhae Bay, Korea, where pollution was progressive, were exposed to gametes of the Pacific oyster for 0, 5, 10, 20, 30, and 60 min to detail the pollutant effects on very young specimens. There was an apparent critical dilution over which adverse effects are evident. This was $10\%$ of the present sediment elutriate, corresponding to 0.3 ng/g on the basis of total polycyclic aromatic hydrocarbons (PAHs) for the oyster. Within the dilution the embryonic development was not influenced by the duration of exposure to its gamete stage. At higher dilutions over the critical dilution, occurrence of abnormality increased dependent on the pollutant dilution and the duration of exposure. Similar trends were also found in larval mortality. However, overall, the chemical toxicity was more significant to morphogenesis than to survival, suggesting a potential recruitment of the pollutants-induced abnormal larvae in the wild population to threaten the population integrity.

• 한국양식학회지
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• 제18권3호
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• pp.200-206
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• 2005

We previously pointed out that the polluted sediment elutriate manifestly affected the early events of reproductive outputs in the Pacific oysters, Crassostrea gigas. A serial dilution of priority xenobiotic sediment elutriates determined by gas chromatography/mass spectrometry (GC/MS) were exposed to gametes of the oyster with different stress burdens to detail the maternal stress transfer to its reproductive outputs. There was an apparent critical concentration over which survival and morphogenesis were significantly affected with more profound damage in morphogenesis. The critical concentration which drives mortality and abnormal morphogenesis of the larvae corresponded to a dilution between 10 and 20% of our elutriate. The adverse effects of the early lives by the xenobiotic exposure over the critical concentration were magnified by the maternal stress from the exposed benzo(a)pyrene (BaP), one of the priority polyaromatic hydrocarbons (PAHs) during the maturation condition. These results indicate that maternal transfer of the xenobiotic compounds from oysters living in the contaminated location might represent a significant adverse effect to their larval population of wild seeds.

• Food Science and Biotechnology
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• 제15권1호
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• pp.91-95
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• 2006

Effects of cultivars, cooking, and processing on hemagglutinin activity were evaluated by observing macroscopic hemagglutination using serial twofold dilution of trypsinized human blood type-O or rabbit blood. Hemagglutinin activity was expressed as maximal geometric dilution fold. Agglutination of rabbit blood was more sensitive compared to human blood. Hemagglutinin activities of glyphosate-tolerant soybean, HS2906, and imported conventional soybeans were not statistically different, although significant differences were observed among conventional soybean cultivars cultivated in Korea (286 to 1535 HU/mg protein). Time required to reach fifty percent inhibition of hemagglutinin activity ($IT_{50}$) value decreased with increasing cooking temperature and pressure. Most effective conventional cooking method to inhibit hemagglutinin activity was pressure-cooking ($IT_{50}$: 1.36 min). Calculated activation energy based on reaction rate constant was 4.88 kcal. No hemagglutinin activities were detected in processed soybean products such as tofu, soybean paste, and soysauce.

• Journal of Plant Biotechnology
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• 제33권1호
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• pp.19-25
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• 2006

저온저항성 BN115 gene과 표지유전자로서 kanamycin에 저항성 있는 nptII gene을 가지고 있는 식물발현용 binary vector pBin19/BNl15가 도입된 A. tumefacience MP90을 국화잎과 공동배양 하였다. 또한 particle bombardment를 이용하여 목적으로 하는 유전자가 식물체에 안정적으로 도입되어 발현됨을 PCR 및 Real-Time PCR 검정으로 확인하였다. 국화잎과 공동배양에 사용된 Agrobacterium은 $5.0{\times}1.0{\mu}m$로 non-sporing, motile, rod 형이며, Callus는 pin이나 cork-borer에 의해 상처 난 잎 가장자리로부터 형성되어 식물체가 재분화 되었다. 유전자 도입조건은 Agrobacterium을$O.D._{600}{\approx}0.5$에서 20분간 공동배양 할 때, Particle bombardment는 helium 압력을 1,100 psi, target 거리를 9 cm로 유지했을 때, 가장 효율이 높았다. 5mg/L kanamycin이 들어 있는 배지에서 선발된 형질전환체는 PCR 분석으로 형질전환여부를 판별할 수 있었으며, 선발 10개체 중 9개체에서 purified pBN115와 같은 크기의 밴드가 형성되었다. Taq-Man probe를 이용한 Real-Time PCR 결과 $45{\sim}0.00045ng/{\mu}{\ell}$ 범위에서 pBN115 gene을 10배씩 serial dilution한 amplification plot는 일정한 간격으로 standard curve를 보였으며, slope는 -3.313975, R2는 0.998319이었다. Amplification plots의 형질전환체 $C_T$값은 $20.75{\sim}33.81$범위였으며, 유전자 copy수는 정량분석을 기초로 산출하였다. pBN115의 plasmid DNA를 serial dilution했을 때, standard는 $5.6{\times}10^{10}/45ng{\sim} 5.6{\times}10^5/0.00045ng\;copies/{\mu}{\ell}$이 었으며, 형질전환체는 $3.86{\times}10^8{\sim}12565.71 copies/{\mu}{\ell}$이었다. 따라서 PCR, Real-Time PCR 분석 결과 저온저항성 유전자가 국화의 genome에 안정적으로 도입되었음이 확인되었다.

• 핵의학기술
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• 제26권1호
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• pp.42-46
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• 2022

핵의학과 검체검사에서 시행되는 모든 정량 검사는 정확도와 정밀도를 고려하여 측정가능범위 및 임상보고 가능범위가 설정되어 있다. 측정가능범위를 벗어난 검체는 희석 실험을 시행하여 최종 검사 결과를 보고해야 한다. 그동안 희석을 진행하는 검체의 수가 많지 않았고, 검사 종목별 희석액이 시약 마다 달라 검사자가 실험 종목마다 적절한 희석배수를 정하여 결과를 보고하는 데 어려움이 있었다. 이에 따라 RIA 검사별 최대 희석배수의 설정 및 임상보고가능범위의 상한치 검증이 필요하다고 판단되었다. 본 연구에서는 KOLAS를 바탕으로 설정된 임상보고 가능범위의 상한치를 검증하였고 그에 따른 각 종목의 최대희석배수를 설정하였다. 서울아산병원에서 시행하고 있는 모든 RIA 검사 중 희석하는 30종의 검사종목을 대상으로 연구를 진행하였다. 2021년 3월부터 7월까지 총 4개월간의 자료를 종목별로 취합하여 분석하였다. 각 검체는 검사 항목별 Kit 내 기재된 희석방법에 따라 D.W, Kit 내 전용 Diluent 혹은 0 Standard로 희석하였으며 2배, 4배 및 10, 10², 10³, 10⁴ 등의 계단희석을 진행한 검체를 대상으로 하였다. 실험 결과의 유효성을 확인할 수 있는 지표로 실측값을 기댓값으로 나눈 백분율을 사용하였다. 본 연구에서는 백분율 허용범위를 80~120%로 설정하였으며 이를 만족한 실험 결과를 연구의 표본이 되는 N값으로 설정하였다. 총 30종의 검사항목 중 백분율 허용범위에 속하는 N값의 수가 5개 이상인 종목은 19종목이었다. 희석배수의 검증 결과 10⁴로 설정된 검사는 𝛼-fetoprotein, Thyroglobulin으로 2종목이며, 10³으로 설정된 검사는 CA-125, CEA, 𝛽-hCG로 3종목, 10²으로 설정된 검사는 Free PSA, PSA, CA15-3, SCC, Ferritin, PTH, Cortisol, Calcitonin, Aldosterone 으로 9종목이다. 10으로 설정된 검사는 𝛽2-Microglobulin, C-peptide, Testosterone 3종목이 있다. 남은 2종목인 Renin Activity와 Follicle Stimulation Hormone은 각각 2배, 4배로 설정하였다. 그 외 특이사항이 있는 항목은 11종목으로 허용범위를 벗어난 결과가 섞여 있어 표본이 부족하거나 희석검체 수가 부족하여 값을 설정하기 어려웠다. 이러한 종목들은 기존 자료를 토대로 희석배수를 설정하였고, 추후 자료를 수집하여 허용범위 내에 속하는 N값의 수가 충족된다면 희석배수를 재설정할 계획이다. 본 연구를 통해 임상보고 가능범위를 실증적 방식으로 검토하고, RIA 검사별 적절한 희석배수를 표준화함으로써 핵의학 검사의 경제성을 높이고, 연구를 통해 검증된 임상보고 가능범위 내에서 더욱 정확한 희석검사결과를 도출하는 데 도움이 되고자 하였다. 이를 통해 핵의학 혈액검사의 전반적인 질 향상을 기대해 볼 수 있으리라 사료된다.

• Archives of Pharmacal Research
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• 제21권2호
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• pp.187-192
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• 1998

The cis- and trans-diastereomers of the 7,8-dihydro-7-deazapurine derivatives were synthesized from the corresponding diastereomers of 4-tran5-cyano-2-methyl-3-phenyl-5-oxopyrrolidine (5), which were reduced from the 2-cis- and 2-tran5-diastereomers of 4-trans-cyano-2-hydroxymethyl-3-phenyl-5-oxopyrrolidine (2) via tosylation, iodination and following elimination respectively. The prepared cis- and ttans-diastereomers of 6-amino-2-mercapto-8-methyl-7-phenyl-7,8-dihydro-7(9H)-deazapurine (8) were transferred to the corresponding 2-methylthio-diastereomers 9 and following desulfurization with Raney-nickel leaded to the cis and trans-diastereomers of 6-amino-8-methyl-7-phenyl-7,8-dihydro-7(9H)-deazapurine (10), respectively. The synthesized 7-deazapurine derivatives were tested for their antibiotic activity by the serial two-fold dilution method.