• 한국대기환경학회지
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• 제25권6호
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• pp.503-511
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• 2009

VOC mixture was fed to a trickle bed air biofilter (TBAB) with step-change in influent mixture concentrations from 50 ppmv to 1,000 ppmv, corresponding to loadings of $5.7\;g/m^3/hr$ to $114.1\;g/m^3/hr$. VOC mixture was an equimolar ratio of two aromatic VOCs, i.e., toluene and styrene, and two oxygenated VOCs, i.e., methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK). The TBAB system employed backwashing as biomass control. The experimental results showed that a critical loading rate for VOC mixture removal was determined to be about $60\;g/m^3/hr$, and critical loading rates for individual VOCs in the mixture were different. Specifically, toluene content in the mixture played a major role in the biofilter overall performance. As VOC mixture was fed beyond the critical loading rate, reacclimation of the biofilter to reach the 99% removal efficiency following backwashing was delayed, which was a critical factor in the biofilter performance. In the mass balance analysis, 63.8% of the carbon equivalent in VOCs removal was used for $CO_2$ production during the experimental runs. The 82.6% nitrogen utilized in the biofilter was contributed to microbial cell synthesis. The obtained results were compared against consistently high efficient performance of TBAB for VOC mixture by employing backwashing as biomass control.

• Clinical and Experimental Reproductive Medicine
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• 제26권1호
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• pp.9-20
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• 1999

The genetic defects in human gametes and embryos can cause adverse effects on overall reproductive events. Biopsy of embryos for preimplantation genetic diagnosis (PGD) offers a new possibility of having children free of the genetic disease. In addition, advanced embryo culture method may enhance the effectiveness of embryo biopsy for the practical application of PGD. This experimental study was undertaken to evaluate the effects of coculture on the development in vitro of biopsied mouse embryos as a preclinical model for PGD of human embryos. Embryos were obtained after in vitro fertilization (IVF) from F1 hybrid mice (C57BLfemale/CBAmale). Using micromanipulation, 1, 2, 3 or 4 blastomeres of 8-cell stage embryos were aspirated through a hole made in the zona pellucida by zona drilling (ZD) with acidic Tyrode's solution (ATS). After biopsy of blastomeres, embryos were cultured in vitro for 110 hours in Ham's F-10 supplemented with 0.4% BSA or cocultured on the monolayer of Vero cells in the same medium. The frequence of blastocyst formation were recorded, and the embryos beyond blastocyst stage were stained with 10% Giemsa to count the total number of nuclei in each embryo. There was no significant difference in the blastocyst formation between the zona intact control group and the zona drilling (ZD) only, or biopsied groups. The hatching rate of all the treatment groups except 4/8 group was significantly higher than that of control group. In all the treatment groups, there was a significant reduction in the mean cell number of embryos beyond blastocyst stage ($50.2{\pm}14.0$ in control group vs. $41.2{\pm}7.9$ in ZD, $39.3{\pm}8.8$ in 7/8, $29.7{\pm}6.4$ in 6/8, $25.1{\pm}5.7$ in 5/8, and $22.1{\pm}4.3$ in 4/8 groups, p<0.05). When the same treatments were followed by coculture with Vero cells, a similar pattern was seen in the blastocyst formation and the hatching rate. However, in all the treatment groups, there was a significant increase in the mean cell number of embryos beyond blastocyst stage with coculture, compared with the parallel groups without coculture. In the cleavage rate of biopsied blastomeres cultured for 110 hours after IVF, there was no significant difference between coculture and non-coculture groups (87.2% vs. 78.7%). However, the mean cell number of embryos developed from the biopsied blastomeres was significantly higher in coculture group ($11.5{\pm}4.7\;vs.\;5.9{\pm}1.9$, p<0.05). In conclusion, biopsy of mouse embryos after ZD with ATS is a safe and highly efficient method for PGD, and coculture with Vero cells showed a positive effect on the development in vitro of biopsied mouse embryos and blastomeres as a preclinical model for PGD of human embryos.

• 한국세라믹학회지
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• 제34권3호
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• pp.314-322
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• 1997

극저 유전특성을 갖는 SiO2 에어로겔의 박막화의 층간 절연막으로써의 응용성이 연구되었다. 점도가 10~14cP인 SiO2 폴리머 졸을 이소프로판을 분위기 하에서 1000~7000m으로 p-Si(111) 웨이퍼 상에 스핀코팅한 습윤겔 박막을 25$0^{\circ}C$와 1160 psing 조건에서 초임계건조하여 0.5 g/㎤ 정도의 밀도(78% 기공율) 와 4000~21000$\AA$ 범위의 두께를 갖는 SiO2 에어로겔 박막을 제조하였다. 박막의 두께와 미세구조를 제어할 수 있는 주요 인자는 졸의 농도, 회전속도 및 습윤겔 숙성시간임을 알 수 있었다. SiO2 에어로겔 박막의 유전상수 값은 giga급 이상의 차세대 반도체 소자에 충분히 응용될 수 있을 정도로 낮은 2.0 정도이었다.

• 생명과학회지
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• 제18권9호
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• pp.1194-1201
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• 2008

본 연구는 유해성 Cochlodinium polykrikoides 적조생물을 대상으로 수온변화에 따른 세포 생화학적 및 생리 활성도를 측정했다. Genomic DNA 함량은 $12^{\circ}C$ 및 $15^{\circ}C$에서 거의 비슷한 0.6을 보였으나, $18^{\circ}C$부터 급격히 높아져서 $24^{\circ}C$ 최고 1.8를 나타내었다. RNA와 total protein도 $24^{\circ}C$에 가장 높은 1.7과 0.07 ${\mu}g$ $ml^{-1}$으로 나타났다. 광합성량도 수온에 따른 큰 변화를 보였다. 빛의 파장에 관계없이 $18^{\circ}C$ 이상에서 현저히 높은 값을 보였다. $24^{\circ}C$ $ETR_{max}$ Ch1-Ch4까지의 범위는 537.9에서 602.5 ${\mu}mol$ electrons $g^{-1}$ Chl ${\alpha}s^{-1}$ 나타났다. Nitrate reductase와 ATPase 효소 활성도는 $24^{\circ}C$에서 각각 0.11 ${\mu}mol$ $NO_{2}^{-}$ ${\mu}g^{-1}$ Chl ${\alpha}h^{-1}$ , 0.78 pmol 100 $mg^{-1}$ 나타났다. CHN 분석에서도 수온에 따라 C, H, N의 함량이 현저하게 상이했다. $27^{\circ}C$ 배양시 $24^{\circ}C$에 비하여 대부분의 세포생리물질이 낮게 보였다. 따라서 C. polykrikoides는 수온 변화에 대하여 세포대사물질의 함량이 많은 차이를 볼 수 있어서 초기 적조 발생 조건은 $18^{\circ}C$로 추측된다. 본 실험의 결과로 $24^{\circ}C$ 이상이 되면 C. polykrikoides 대번식은 세포 내 생리물질의 현저한 저하로 형성되기가 어려울 것으로 보인다.

• Journal of Ginseng Research
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• 제28권1호
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• pp.39-44
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• 2004

홍삼추출액의 신경성체줄기세포 성장과 생존에 미치는 영향을 분석하고자 human neuronal stem cell line인 F3 cell을 배양한 후 홍삼추출액을 여러 농도로 희석하여 MTT assay로 cell viability를 측정하였고 FACS analysis로 cell Cycle변화를 측정하였다. 특정한 농도에서는 세포가 증식되는 경향을 보였으며 농도가 증가되면서 viability가 감소되는 현상을 확인할 수 있었다. Cell cycle 분석상 세포증식시에는 5 phase 및 G2/M phase가 증가되는 경향을 보였고, viability가 감소되면서 S phase가 감소되고 G0/G1 phase 가 증가 되었다. 한편 DNA fragmentation이 cell viability감소에 따라 증가되었으나, Caspase 3 activation 또는 Bax expression과는 관련성이 적었다.

• Asian-Australasian Journal of Animal Sciences
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• 제18권1호
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• pp.17-21
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• 2005

The effect of melatonin on in vitro embryo development and the expression of antioxidant enzyme gene in preimplantation porcine embryos was determined by modified semi-quantitative single cell RT-PCR. Porcine embryos derived from in vitro maturation /in vitro fertilization were cultured in 5% $CO_2$ and 20% $O_2$ at $37^{\circ}C$ in NCSU23 medium. Melatonin was added to medium at concentration of 1nM, 5 nM, and 10 nM. When treated with 1nM (39.0%) of melatonin, the developmental rate of embryos beyond the morula stage were higher than that of control group (31.0%) (p<0.05). Number of inner cell mass and tropectoderm cell in control (23.0${\pm}$0.5 and 17.3${\pm}$0.8), 1 nM (23.6${\pm}$0.6 and 19.0${\pm}$0.5), and 5 nM (23.3${\pm}$1.1 and 16.3${\pm}$0.8) treated with melatonin were higher than in 10 nM (20.0${\pm}$0.5 and 13.3${\pm}$0.8) treated with melatonin (p<0.05). To develop an mRNA phenotypic map for the expression of catalase, bax and caspase-3, single cell RT-PCR analysis were carried out in porcine IVM/IVF embryo. Catalase was detected in 0, 1 and 5 nM supplemented with melatonin, but bax and caspase-3 were detected in 10 nM treated with melatonin.

• Asian-Australasian Journal of Animal Sciences
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• 제19권9호
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• pp.1354-1360
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• 2006

Maize-soybean meal diets with 0, 100, 200 and 300 g/kg double zero rapeseed meal ('00' RSM) with and without an enzyme mixture (xylanase, pectinase, cellulase) at a level of 1.6 g/kg were evaluated with 624 day-old broiler chicks for 5 weeks. The birds were randomly allocated to eight dietary treatments with three replicates of 26 birds each. Average daily gain (ADG) and feed intake (FI) were recorded weekly and ileal viscosity, organ weights, serum enzyme activity, hormonal profile and hematological parameters were measured at the end of week 5. Average daily gain during the weekly periods was significantly influenced by the dietary level of '00'RSM (p<0.01). Inclusion of '00' RSM improved the ADG up to day 28 with the increased level; beyond that time no improvement was recorded when compared to control groups. However, ADG from 1-35 days was significantly different between 300 g/kg inclusion level of '00' RSM and the control diet. Inconsistent decline in feed intake and feed conversion ratio was observed up to day 21 and the trend was reversed thereafter. The proportion of '00' RSM in the diet had a significant ($p{\leq}0.05$) influence on thyroid weight but had no effect on the relative weights of liver and heart, serum enzyme activities (${\gamma}$-glutamyl transferase, alanine amino transferase and aspartate amino transferase), thyroid hormones ($T_3$ and $T_4$), hemoglobin level and hematocrit. Significant improvement in ADG was recorded during the 2nd week of age with the addition of enzyme, whereas for all other periods, including the whole period of the trial, higher but non-significant ADG was observed. FI and FCR were not affected by the addition of enzyme but there was a numerical reduction in FCR during the whole period. The addition of enzyme reduced the ileal viscosity at all levels of '00' RSM inclusion. The results suggest that '00' RSM can be included up to 300 g/kg in broiler diets without any adverse effects on health and performance. The addition of commercial enzyme mixture containing xylanase, pectinase, cellulase to broiler diets containing '00'RSM has some effect on growth rate and feed conversion efficiency.

• 한국식품영양과학회지
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• 제34권4호
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• pp.557-566
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• 2005

본 연구는 오븐에서 굽는 거품형 케이크 중 단단계법을 찌는 방법에 적용하여 혼합방법에 따른 거품형 찜 케이크의 가장 적합한 배합비율을 반응표면분석법으로 찾아 단단계법을 이용한 거품형 찜 케이크의 상품화와 산업화를 위한 기초자료를 만들고자 하였다. 휘핑 시간($X_1,\;4\~20$분),밀가루의 양$X_2,\;460\~540\;g$과 유화제의 양$(X_3,\;16\~24\;g)$을 독립변수로 설정하고, 색도, 부피, 텍스쳐 항목을 반응변수로 하여 최적화한 결과 물리적 특성 중 부피의 경우 16개의 실험조건에 따라 $1,300\~1,584\;mL$, 색도의 L값은 $83.64\~67.55$, a값은 $0.20\~2.70$, b값은 $30.49\~35.03$, ${\Delta}E$는 $32.02\~36.49$, 경도는 $209.82\~349.20\;g$, 검성은 $209.82\~349.20\;g$, 씹힘성의 경우 $120.92\~218.86\;g{\cdot}cm$ 범위의 결과를 나타내었고, 관능적 특성을 평가한 결과 외관 $4.00\~7.25$, 색 $4.83\~7.50$, 냄새 $4.40\~7.00$, 맛 $4.80\~7.02$, 부드러운 정도 $4.20\~7.50$, 촉촉한 정도 $5.44\~7.67$, 전반적인 기호도 $5.00\~7.98$의 점수를 받았다. 회귀식을 검증한 결과 부피, 경도, 검성과 씹힘성은 $5\%$ 이내의 수준에서 회귀식의 유의성이 인정되었고, 관능적 특성의 냄새, 부드러운 정도, 촉촉한 정도와 전반적인 기호도는 $5\%$ 이내에서, 맛은 $1\%$ 이내의 수준에서 회귀식의 유의성이 인정되었다. 독립변수가 각 반응변수에 미치는 영향을 본 결과 유화제의 양이 물리적 특성에 가장 큰 영향을 주었고, 관능적 특성에서는 휘핑 시간과 유화제의 양이 중요한 변수로 작용하였다. 반응표면의 정상점의 형태는 물리적 특성에서 색도의 b값만 정상점에서의 형태가 최대점을 나머지 모든 항목은 안장점의 형태를 나타내었다. 관능적 특성 결과 전반적인 기호도의 경우 안장점의 형태를 보였고, 그 이외의 항목은 최대점의 형태를 나타내었다. 결정된 회귀식의 계수를 바탕으로 3차원 반응표면을 도식화한 결과 최적조건보다 과도한 휘핑 시간과 유화제 첨가는 오히려 부피가 감소하였고, 관능검사 결과 낮은 점수를 받아 좋아하지 않았다. 독립 변수에 영향을 받으며 유의적인 차이가 인정된 반응변수에서 찜 케이크의 품질특성에 중요한 요인으로 작용하는 물리적 특성 중 부피, 경도, 그리고 관능적 특성 중 맛, 냄새, 부드러운 정도, 촉촉한 정도, 전반적인 기호도의 contour map을 중첩하여 특성을 모두 만족시켜주는 교집합을 각각의 독립변수의 최적의 조건으로 선정하였다. 그 결과 휘핑 시간 $11\~13$분, 밀가루의 양 $470\~486\;g$, 유화제의 양 $19\~20\;g$으로 각각 나타났다. 이상의 예측된 최적 조건을 검증하기 위하여 최적 조건 범위내의 중간점 즉, 휘핑 시간 12분, 밀가루의 양 478 g과 유화제의 양 20 g을 최적점으로 설정하여 실제 단단계법으로 거품형 찜 케이크를 만들어 물리적 특성을 측정하여 본 결과 실제 실험 값들은 예측된 값들과 유사한 수준의 결과를 보였다.

• Journal of Microbiology and Biotechnology
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• 제21권5호
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• pp.483-493
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• 2011

An acid phosphatase (HppA) activated by $NH_4Cl$ was purified 192- and 34-fold from the periplasmic and membrane fractions of Helicobacter pylori, respectively. SDS-polyacrylamide gel electrophoresis revealed that HppA from the latter appears to be several kilodaltons larger in molecular mass than from the former by about 24 kDa. Under acidic conditions (pH${\leq}$4.5), the enzyme activity was entirely dependent on the presence of certain mono- and/or divalent metal cations (e.g., $K^+$,$ NH_4{^+}$, and/or $Ni^{2+}$). In particular, $Ni^{2+}$ appeared to lower the enzyme's $K_m$ for the substrates, without changing $V_{max}$. The purified enzyme showed differential specificity against nucleotide substrates with pH; for example, the enzyme hydrolyzed adenosine nucleotides more rapidly at pH 5.5 than at pH 6.0, and vice versa for CTP or TTP. Analyses of the enzyme's N-terminal sequence and of an $HppA^-$ H. pylori mutant revealed that the purified enzyme is identical to rHppA, a cloned H. pylori class C acid phosphatase, and shown to be the sole bacterial 5'-nucleotidase uniquely activated by $NH_4Cl$. In contrast to wild type, $HppA^-$ H. pylori cells grew more slowly. Strikingly, they imported $Mg^{2+}$ at a markedly lowered rate, but assimilated urea rapidly, with a subsequent increase in extracellular pH. Moreover, mutant cells were much more sensitive to extracellular potassium ions, as well as to metronidazole, omeprazole, or thiophenol, with considerably lowered MIC values, than wild-type cells. From these data, we suggest that the role of the acid phosphatase HppA in H. pylori may extend beyond 5'-nucleotidase function to include cation-flux as well as pH regulation on the cell envelope.

• 한국양식학회지
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• 제15권4호
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• pp.253-260
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• 2002

To find the optimal rearing conditions for Saxidomus purpuratus juvenile, filtering activity was estimated as functions of algal concentration and temperature by measuring the rates of clearance (CR) and ingestion (IR), when S. purpuratus was feeding. The clams were fed on unialgal diet of Isochrysis galbana at 6 algal concentrations (4.6$\times$$10^4$~2.6$\times$$10^6$ cells/ml) and at 6 temperatures (5, 10, 15, 20, 25, and 30^{\circ}C ). Algal concentration significantly affected the CR and the IR at all temperatures. At lower algal concentrations, CR increased, but decreased beyond a particular concentration. The maximum CR ($CR_{max}$) at 5, 10, 15, 20, 25, and 30^{\circ}C were 0.30, 1.73, 5.95, 15.17, 21.12, and 0.33 $l/g/h$, respectively. Below the level of 5.6$\times$10$^{5}$ cells/ml, IR increased as algal concentration increased, but was saturated at higher concentrations. To maintain high growth rate of S. purpuratus, I. galbana should be supplied with more than 5.6$\times$10$^{5}$ cells/ml. The maximum IR ($IR_{max}$) at 5, 10, 15, 20, 25 and30^{\circ}C were $2.2$\times$10^8, $1.5\times$10^9, 3.4$\times$10^9, 4.9$\times$10^9, 5.3$\times$10^9, and 1.0$\times$10^8$ cells/g/h, respectively. As for temperature, both $CR_max$ and $IR_max$ increased remarkably with raising temperature from 5 to 25^{\circ}C, but rapidly decreased at 30^{\circ}C. Between 15 and 25^{\circ}C $CR_{max} and IR_{max}$ were higher and most stable, At this temperature range, the $Q_{10}/s for CR_{max} and IR_{max}$ were 3.5 and 1.6, respectively. Therefore the optimal thermal range for the juvenile is 15~$25^{\circ}C$. The annual variation in IR$_{max}$ predicted by natural seawater temperature shows that inactive period (with lower $IR_max$) lasts for 5 months (from December to April). To ensure higher growth of juvenile during this inactive period at hatcheries, rearing temperature should be elevated to $15^{\circ}C$.>.