• 상하수도학회지
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• 제30권6호
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• pp.715-723
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• 2016

This study investigated the effect of high concentration of free ammonia on microalgal growth and substrate removal by applying real wastewater nitrogen ratio. To test of this, the conditions of free ammonia 1, 3, 6, 9, 12, 15 mg-N/L are compared. After 3 days of incubation, algal growth of Chlorella vulgaris and carbon removal rate are respectively lower in the reactors of FA 12, 15 mg-N/L compared to the others. This indicates that the high concentration of free ammonia, in this case, above 12 mg-N/L, has negative effect on algal growth and metabolic activity. Also, high concentration of free ammonia causes the proton imbalance, ammonium accumulation in algae and has toxicity for these reasons. So, we have to consider free ammonia in applying the microalgae to wastewater treatment system by the way of diluting wastewater or controlling pH and temperature.

• KSBB Journal
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• 제9권2호
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• pp.133-139
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• 1994

Aureobasidium pullulans를 설탕 및 맥아당을 주 탄소원으로 하는 배지에서 각각 배양하면서 여러 종류의 올리고당류의 합성, 기질 이용성, 그리고 과당 전이효소 및 포도당전이효소의 생산특성에 대해 고찰하였다. 맥아당 배지에 비하여 설탕배지에서 초기 기질의 소비속도가 더 빨랐고 합성된 올리고당류는 두 경우 모두 최대 중합도 6까지의 올리고당류를 생산하였고, 이때 합성된 올라고당류의 최대 농도는 초기 설탕농도 100g/ㅣ 의 경우에서 58g/ㅣ 이었다 이들은 대부분 배양 중에 탄소원으로 다시 이용되었으나 중합도 6의 이소말토올리고당은 기질로 이용되지 않고 배양 말기까지 계속 잔존하였다. 설탕을 주 탄소원으로 하는 배지에서 맥아당은 과당전이효소 및 포도당전이효소의 생산을 촉진시켰으나, 맥아당을 주 탄소원으로 하는 배지에서 설탕은 포도당전이 효소의 생산에 전혀 영향을 미치지 않았다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2000년도 제18회 학술발표회 논문개요집
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• pp.175-175
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• 2000

Si(100) surfaces were exposed to gas-phase thermal-energy hydrogen atoms, H(g). We find that thermal H(g) atoms etch, amorphize, or penetrate into the crystalline silicon substrate, depending on the employed Ts range during the H(g) exposure. We find that etching is enhanced as Ts is lowered in the 300-700K range, while amorphous silicon hydride (a-Si:H) formation dominates at a Ts below 300K. This result was well explained by the fact that formation of the etching precursor, SiHx(a), and amorphization are both facilitated by a lower Ts, whereas the final step for etching, SiH3(a) + H(g) longrightarrow SiH3(g), is suppressed at a lower Ts. we also find that direct absorption of H(g) by the crystalline bulk of Si(100) substrate occurs within a narrow Ts window of 420-530K. The bulk-absorbed hydrogen evolved out molecularly from Si(100) at a Ts 80-120K higher than that for surface monohydride phase ($\beta$1) in temperature-programmed desorption. This bulk-phase H uptake increased with increasing H(g) exposure without saturation within our experimental limits. Direct absorption of H(g) into the bulk lattice occurs only when the surface is atomically roughened by surface etching. While pre-adsorbed hydrogen atoms on the surface, H(a), were readily abstracted and replaced by D(g), the H atoms previously absorbed in the crystalline bulk were also nearly all depleted, albeit at a much lower rate, by a subsequent D(g) at the peak temperature in TPD from the substrate sequentially treated with H(g) and D(g), together with a gas phase-like H2 Raman frequency of 4160cm-1, will be presented.

• 미생물학회지
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• 제5권2호
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• pp.69-78
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• 1967

Kim, Jong Hyup, (Div. of Biology, Atomic Energy Research Institute.) Studies on the Cellular Metabolism in Microorganisms as influenced by Gamma-irradiation(II). On respiration rate and dehydrogenase activity of yeast cells irradiated by gamma ray from cobalt-60. 1. Oxygen uptake rate of the gamma irraiated yeast cells had been measured with Warburg's manometer, and the $O_{2}$-uptake was compared with those of normal cells. The rate of endogetious respiration increases in its $O_2$-uptake at 150, 000 rentgen dose, and at higher rentoen doses it was decreased. Exogenous respiration begin to decrease in its O_2$-uptake at 5, 000r. doses of irradiation, further decrease with increasing of doses unproportionally. 2. It appears that plasma-membrane and nuclear membrane of yeast cells have changed and denatured by gamma-irradiation, as exogenous respiration of glucose had been decreased at a dose of 200, 000r's irradiation. 3. The activity of glucose, alcoholic, lactic, succinic and glutamic deliydrogenase (G.D.H., A.D.H., L.D.H., S.D.11., and GL.D.H.) in the gamma irradaited cells had been assayed by T.T.C.(Triphenyl tetrazolium chloride) method and spectrophotometry, the obtained results were compared with those of normal cells. 4. At a dose of and 10, 000 rentgens' irradiation of gamma ray, the activty of each debydrogenase (G.D.H., A.D.H., L.D.H., ) shows a sharp and highest peak in optical absorbalicy, but each abtivity of S.D.H and Gl.D.H shows its' maximum peak at a dose of 30, 000r. 5. The curve of each dehydrogenase activity was found to be rhythmical according to dose-rate of gamma irradiation. 6. Comparing with activity of debydrogenase each other, the maximum peak in optical absorbency can be arranged according to order as follows; glucose > alcoholoic > lactic > glutamic > succinic, this order is identical to the order of breakdown utility in respiration of normal yeast cells. 7. The activity of dehydrogenase experimented exhibit a resistance against gamma irradiation at lethal dose of cells, and the activity of dehydrogenase are found to be much resistant than those of respiratory system. We may assume that the membrane substrate of mitochondria or cytoplasm had been destructed by gamma-irradiation much more than that of dehydronase system.

• 상하수도학회지
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• 제12권1호
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• pp.96-101
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• 1998

Substrate inhibition of 2,4-dinitrophenol (DNP) degradation was investigated using activated sludge which had been adapted to mineralize DNP. DNP is a metabolic uncoupler, preventing cells from making energy for growth and it has been suggested that pH may be important in mitigating effects of uncouplers. After acclimation of the activated sludge, the effect of pH on toxicity of DNP at high concentration (75 mg/L) was investigated, over a pH range of 5 to 9. DNP inhibition was found to be strongly dependent on mixed liquor pH. The DNP degradation rate was highest in the pH range of 6.95 to 7.84; at pH 5.94 degradation of 75 mg/L DNP was significantly inhibited; at pH < 5.77, DNP degradation was completely inhibited after approximately 30% of the DNP was degraded. By comparison, no significant effect of pH variation in the same range was seen on glucose uptake by the activated sludge culture.

• Journal of Microbiology and Biotechnology
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• 제2권2호
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• pp.129-134
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• 1992

Segregational instability of a recombinant plasmid, pDML6, encoding extracellular $\beta$-lactamase in Streptomyces lividans PD6 was characterized by growth kinetic analysis. The quantitative determination of the plasmid harbored in the mycelia was evaluated with mycelia fragmented mechanically, and also with colonies regenerated from protoplasts. Conditions for the formation of protoplasts and regeneration of protoplasts were established. The maximal specific growth rates of the host strain and the plasmid-harboring strain in a chemically defined medium without selection pressure were the same. The probability of plasmid loss from the harbouring cells was higher at higher growth rates. Mathematical models for the prediction of cell growth, substrate uptake, and accumulation of the cloned gene product were developed.

• Asian Journal of Atmospheric Environment
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• 제6권3호
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• pp.137-146
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• 2012

Poor indoor air quality is now worldwide concern due to its adverse impacts on our health and environment. Moreover, these impacts carry a significant burden to the economy. Various technical approaches (e.g., biological, activated carbon fiber (ACF), photocatlytic oxidation (PCO), etc.) have gained popularity in controlling indoor volatile organic compounds (VOCs). This is because removing indoor VOC sources or increasing ventilation rates is often not feasible or economical. This review provides an overview of the various air purification technologies used widely to improve indoor air quality. Although most of these technologies are very useful to remove indoor VOCs, there is no single fully satisfactory method due to their diversity and presence at the low concentration. To achieve technical innovations and the development of specific testing protocols, one should possess a better knowledge on the mechanisms of substrate uptake at VOC concentrations.

• Journal of Applied Biological Chemistry
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• 제42권3호
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• pp.130-133
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• 1999

Lipoxygenase activities of three cultivars of black rice (Chindo, Suwon-415, Yongkeum-1) were determined using an oxygen polargraphic method to measure oxygen uptake. Studies at different pH levels revealed that the optimum pH was about pH 7.0 for Suwon-415 and pH 7.5 for Chindo and Yongkeum-1. The specific activities of Chindo, Suwon-415 and Yongkeum-1 at optimal pH were 41.0, 27.3, and 29.6 unit/mg-protein, respectively. In all the cultivars, there was an increase in the activity with increase in reaction temperature. Enzyme activity was tested at different concentrations of the substrate. The resulting $K_m$ and $V_{max}$ values of Chindo, Suwon-415, and Youngkeum-1 were 0.059, 0.050, and 0.066 mM and 2020, 2283, and 1616 unit/g-grain, respectively. Enzyme activity decreased at all storage temperatures(25, 4, and $-40^{\circ}C$).

• 약학회지
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• 제47권4호
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• pp.218-223
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• 2003

Effect of taurine treatment on metabolism of glutathione (GSH) was studied in adult male ICR mice. An acute injection of taurine (250 mg/kg, ip) resulted in a significant decline of hepatic GSH level at t = 6 hr, but plasma GSH level was not altered. The activity of GSH-related enzyme in liver, such as GSH peroxidase, GSSG reductase, GSH S-transferases, ${\gamma}$-glutamylcysteine synthetase or ${\gamma}$-glutamyltranspeptidase, was not affected by taurine at t = 2.5 or 6 hr. Plasma cysteine and cystine levels were elevated rapidly following taurine treatment. Hepatic cysteine level was decreased by taurine, reaching a level approximately 70％ of control at t = 4 and 6 hr. In conclusion, the results indicate that an acute dose of taurine decreases hepatic GSH level by reducing the availability of cysteine, an essential substrate for synthesis of this tripeptide in liver. It is also suggested that taurine may decrease the cysteine uptake by competing with this S-amino acid for a non-specific amino acid transporter.

• 한국토양비료학회지
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• 제41권3호
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• pp.177-183
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• 2008

상토에 함유된 Na이온이 과채류의 육묘에 미치는 영향을 조사하기 위하여 온도조건에 따른 상토의 수분변화, Na이온 및 EC의 경시적 변화, 광합성율, 증산율, 잎의 수분상태, 묘소질, 생육 및 수량성에 대한 실험을 실시하였다. 육묘온도가 $15^{\circ}C$에서는 상토의 수분감소는 적어 3일이 경과하더라도 관수개시점에 도달하지 않았다. 관수 1시간 후 부터 상토로부터 Na 이온이 유리되어 22시간이 지날 때 까지 Na의 농도가 계속 증가하였으며 Na 함량의 증가에 따라 EC의 상승이 있었다. 또한 관수회수가 증가함에 따라 Na의 세탈에 따른 Na 농도가 감소되었고 Na 농도감소에 비해 EC의 감소폭은 적은 편이었다. 양이온 비율중 Na 함량이 60% 이상일 경우 저온에서는 광합성율, 증산율의 감소가 큰 편이었고 포화수분부족도 또한 저온에서 큰 폭으로 높아졌다. Na 함량이 높은 상토에서 육묘된 오이묘는 초장, 세근수 등이 대조상토에 비해 낮은 편이었고 본포 정식후에도 생육이 불량하여 48%정도의 수량감소를 초래하였다.