• KSBB Journal
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• v.11 no.2
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• pp.201-210
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• 1996

The production of polyhydroxyalkanoate(PHA) from glucose by batch and fed-batch culture of Pseudomonas sp. HJ was studied. In batch culture using fermentor, 400 rpm of agitalion speed, 2 vvm of aeration rate, 18 hours of inoculum age, and 5% (vlv) of inoculum size were optimal. PHA production was not increased by deficiency of oxygen. In a batch culture, the final call mass was $6.251g/\ell$, and PHA content was 20% of dry cell weight. In a constant feeding fed-batch culture, cell mass increased to $33.24g/\ell$, and PHA content reached 48.9% of dry cell weight. In an intermittent feeding fed-batch culture, cell mass increased to $37.89g/\ell$, and PHA content reached 53.5% of dty cell weight.

• KSBB Journal
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• v.11 no.2
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• pp.246-253
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• 1996

An obligatory methanotroph Methylosinus trichosporium OB3b was cultivated for the production of poly-${\beta}$-hydroxybutyric acid(PHB) in shake-flask using liquefied natural gas(LNG) as the sole source of carbon and energy. The maximal specific growth rate decreased by 40% using LNG compared with that obtained with pure methane. This is attributed to the inhibition by ethane and propane presents in the LNG as impurities. For the production of PHB, two-stage culture separating the production stage from the growth stage was carried out. PHB accumulation was observed after switching nutrient-sufficient to nutrient-limited condition of non-carboneous component (NO3-, PO43-, K+, Na+, Fe2+, or Mg2+). The limitation of K+ or Mg2+ resulted in relatively high PHB content, but the highest content was obtained by nitrate limitation. The optimal pH and temperature for PHB accumulation was 7.0 and $30^{\circ}C$. Under the optimal condition the maximal PHB content was about 45% after 4-day cultivation.

• The Korean Journal of Nuclear Medicine
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• v.27 no.2
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• pp.285-292
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• 1993

Avidin과 biotin의 높은 결합력을 이용하여 종양 영상을 개선하는 방법이 많이 연구되고 있다. 본 실험에서는 이러한 목적으로 쓰기 위하여 적당한 $^{99m}Tc$ 표지 avidin을 제조하였다. Avidin을 표지하기 위하여 우선 $^{99m}Tc$과 안정한 킬레이트를 형성할 수 있는 benzoylmercaptoacetyltriglycine (Bz-MAG3)과 biocytin을 화학적으로 결합시킨 Bz-MAG3-biocytin을 합성하였다. 이 화합물을 Tc-99m으로 표지시켜 avidin 또는 streptavidin을 1:1로 섞어 줌으로서 Tc-99m으로 표지된 avidin과 streptavidin을 제조하였다. 이들의 생쥐 생체내 분포를 조사한 결과 avidin의 경우 높은 간(56.6%, 10min)과 신장(28.5%, 10min) 축적을 보였고 streptavidin의 경우 높은 신장 축적 (28.9%, 21hr)을 보였다. Avidin의 높은 정상 조직 축적을 줄이기 위하여 succinic acid를 결합시켜 등전점(pI)을 낮춘 다음 같은 실험을 하여 본 결과 신장 축적율은 pI가 $7.0{\sim}9.3,\;5.5{\sim}6.2,\;4.0{\sim}4.8$로 낮아졌을 경우 19.0%, 3.1%, 1.7%로 각각 떨어졌지만 간에의 축적은 pI 변화에 따른 상관성을 찾아 볼 수가 없었다. 체내 제거율을 측정하여 본 결과 pI를 변화시킨 avidin과 변화시키지 않은 avdin들은 반감기가 13.5에서 16.0시간 사이로 큰 차이점을 보이지 않았는데 streptavidin은 반감기 61.5시간 정도로 느리게 제거된다는 것을 알았다. 이 실험의 결과 1. Avidin을 $^{99m}Tc$-MAG3-biocytin으로 안정하게 표지할 수 있었고, 2. pI가 낮아진 avidin은 신장에의 축적율이 크게 감소되었으며, 3. $^{99m}Tc$으로 표지된 avidin과 streptavidin은 먼저 간으로 흡수된 후 대사된 다음 신장으로 배설된다는 사실을 알았다.

• KOREAN POULTRY JOURNAL
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• v.4 no.6 s.32
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• pp.88-89
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• 1972

무제한 급수하면 저에너지 사료를 섭취하는 닭은 모자란 에너지의 보충을 위해 사료를 더 많이 섭취하여 에너지의 제한 효과가거의 없었고 제한급수하면 사료를 충분히 섭취할 수 없기 때문에 대조구의 약 70$\%$밖에 섭취못했다. 따라서 이것이 성성숙을 4$\~$4 1/2주 지연시킨 요인이었으며 체지방 축적도 감소시켰다. 성성숙 지연결과 성숙이 지연된 닭은 총 산란수가 훨씬 많고 비정상란의 수가 훨씬 적으며 대란율도 훨씬 높다. 육성중 폐사율은 더운 여름철에도 급수의 제한과 상관없었으며 산란중 폐사율은 오히려 성성숙시의 체중 혹은 체지방 축적과 정비례 했다. 이상으로 저에너지 사료를 급여하면서 급수제한(격일제 급수)하는 방법이 대추의 에너지 섭취를 제한시키는 간단하고 효과적인 방법임이 입증되었다.

• Journal of fish pathology
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• v.21 no.1
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• pp.57-66
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• 2008

Striped bitterling, Acheilognathus yamatsutae (TL: 4.25 ㎝, TW: 0.73 g)were exposed to 0.3, 1.3, 17.6 and 33.7 ㎍ L-1 (nominal concentrations) of nonylphenol (NP) for a period of 20 weeks. We studied on accumulation, growth and survival rate. After 20 weeks of exposure, the accumulation of NP in the body of the female and male was increased with increasing dose-dependent and female was higher than male. 4 weeks of exposure, TL of female striped bitterling was found to be increased in all of the dose group compared to control and 12 weeks of exposure, similar or some decreased in all of the dose group compared to control. 20 weeks of exposure, increased in all of the dose group compared to control and TL at 33.7 ㎍ NP L-1 were significantly higher than those in control (p <0.05). 4 weeks of exposure, TL and TW of male striped bitterling was found to be increased in all of the dose group compared to control and significantly higher in TL of 33.7 ㎍ NP L-1 (p <0.05). 12 and 20 weeks of exposure, TL and TW decreased in all of the dose group compared to control and significantly lower in 1.3 ㎍ NP L-1 of 12 weeks. Survival rate in both groups decreased with increasing NP concentration and there was a significant difference between control group and experimental groups exposed to each NP concentration.

• Journal of Animal Science and Technology
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• v.46 no.1
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• pp.39-48
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• 2004

This experiment was conducted to investigate the effect of continuous feeding of probiotics on growth performance, nutrient digestibility, blood urea nitrogen(BUN) and immune responses in pigs. Treatments were 1) Control(basal diet), 2) P-O.l(basal diet + 0.1% probiotics) and 3) P-0.2(basal diet + 0.2% probiotics). In growth trial, a total of sixty pigs(6.17 $\pm$ 0.45 kg average body weight) weaned at 21 days of age were used. All pigs were assigned according to sex and body weight, and each treatment had 5 replicates of 4 pigs per pen in a randomized complete block(RCB) design. During 0${\sim}$8 weeks, there was no significant difference in average daily gain(ADG), average daily feed intake(ADFI) and gain:feed ratio(GfF) among treatments. During 9 - 20 weeks, ADG was improved significantly in pigs fed P-O.I or P-0.2 diets when compared to the pig fed control diet(P <0.05), but there was no significant difference in ADFI and GfF ratio. During overall period, ADG, ADFI and GfF ratio were not significantly different among treatments. In the first metabolic trial(17.93 $\pm$1.45kg average body weight), apparent digestibility of OM, protein, fat in pigs fed P-O.l and P-0.2 diets were greater than in pigs fed control diet(P <0.05) and ash digestibility in pigs fed P-0.2 diet was significantly higher than in pigs fed control diet(P <0.05). Calcium digestibility in pigs fed P-0.2 diet was significantly higher than in pigs fed control and P-O.I diets(P <0.05). Fecal-N excretion was lower in pigs fed P-O.! and P-0.2 diets than in pigs fed control(P <0.05). In the second metabolic trial(41.80 $\pm$ 2.68kg average body weight), there was no significant difference among treatments in apparent digestibility of nutrients and N-retention. In blood assay for the BUN and immune responses investigations, there was no significant difference among treatments during overall period of experiment. Therefore, this experiment suggested that probiotics supplementation could improve growth performance and nutrient digestibility of pigs.

• Journal of Environmental Health Sciences
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• v.9 no.1
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• pp.63-76
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• 1983

중금속은 해수에서보다 해수중의 생물계에 그 농도가 더 높은 것으로 알려져 있으며 수은도 무기형으로 생물계에 존재하다가 생물활동으로 인해 알킬형으로 변한다. food chain이 미량금속 축적의 주통로로 알려져 있으나 그외 몇가지 방법이 제시되고 잇다. 특히 연체동물은 미량금속의 축적현상이 온도, 폭로시간, 시간, 생리적 활동에 다라 상당히 달라진다. 또한 유기알킬 수은이 무기수은보다 비교적 낮은 독성을 나타내지만 후자의 피해도 무시할 수는 없다. 굴(crassostrea virginica)은 염화수은농도가 비교적 낮은 상태에서도 상\ulcorner량의 축적현상을 보여주었다. 두개의 compartment system을 연계적인 상태에서 보면 첫 compartment에서의 초기축적은 가역적이었으나 둘째 Compartment에서 측정된 원실율로 보아 비가역적 축적이상을 확인해 주었다. 뿐만 아니라 미량금속이 아가미와 외부 근육에서 가장 높은 축적률을 보인것은 flow system의 regression moder과 매우 흡사함을 암시하며 농도가 낮은 상태에서의 축적이상에 중요한 의미를 부여하였다.

• Journal of Life Science
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• v.25 no.2
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• pp.164-173
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• 2015

To investigate the effect of lactic acid bacteria on the heavy metal adsorption from internal organs and blood, lactic acid bacteria were isolated from human feces. Some strains resistant to heavy metals were selected by incubation in agar media containing each of chrome and cadmium salts. Among them, a strain named KP-3 was ultimately chosen due to its higher growth rate in selective broth medium containing the heavy metals at the concentration of 0.01%. The strain was identified as Lactobacillus sp. based on its morphological, cultural and physiological characteristics. For evaluating the ability to prevent accumulation of heavy metals by selected Lactobacillus sp. strain in vivo, Sprague Dawley rats were fed with heavy metal salts (cadmium, chrome and lead) with or without cultured whole cells for 7 days. The amounts of heavy metals accumulated in liver, kidney and blood were analyzed. As a result, chrome was accumulated to kidney mostly, and lead was frequently found in liver and kidney. Experimental group (rats fed with lactic acid bacteria) showed less accumulation of heavy metal than control group (rats fed with saline solution). The inhibition rates of heavy metal accumulation were calculated to 41.8% (Cd), 33.4% (Cr) and 44.2% (Pb). Especially, feeding lactic acid bacteria strongly reduced accumulation of cadmium in blood. The results showed that feeding Lactobacillus sp. KP-3 could prevent the bioaccumulation of heavy metals in the living body.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.6
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• pp.481-486
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• 2011

The evaluation of supercooled water droplet impingement characteristics of full-scale aircraft components in wind tunnels under icing conditions has been severely limited by the relative size of the component and the test facility. The concept of truncated airfoil sections has been suggested in order to extend the operational range of icing tunnels. With proper deflection of the small trailing-edge flap on the truncated airfoil the local pressure distribution may remain very close to that of the full-scale airfoil. In this study the shape of a truncated flapped airfoil is investigated for various deflection angles. To validate the truncated flapped airfoils, air flow and collection efficiency over the truncated airfoil are compared with the results of the full-scale airfoil obtained from the state-of-the-art icing simulation code.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.1
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• pp.70-75
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• 1992

This study was carried out to investigate the characteristics of a mutant, Pseudomonas maltophilia H-8M selected with the treatment of Pseudomonas maltophilia H-8 by N-methyl-N-nitro-N-nitrosoguanidine(MNNG). This mutant showed highest ability of cadmium accumulation. The growth rate of Pseudomonas maltophilia H-8M showed about 80% in 1000ppm Cd containing medium when compare with control for 36h at $30^{\circ}C$. Pseudomonas maltophilia H-8M not inhibited on the growth in addition of various heavy metal such as $Hg^{2+}$, $Zn^{2+}$, $Pb^{2+}$, $Cu^{2+}$, $Cr^{2+}$ and $Co^{2+}$, but inhibited in $Sn^{2+}$ containing medium, respectively. Pseudomonas maltophilia H-8M was accumulated the highest cadmium level of 62.3% on whole cell in the medium containing 50 ppm and 80% of accumulated cadmium was distributed in the cell wall.