• 대한임상독성학회지
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• 제17권2호
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• pp.66-78
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• 2019

Purpose: Thallium (TI+) autometallography is often used for the imaging of neuronal metabolic activity in the rodent brain under various pathophysiologic conditions. The purpose of this study was to apply a thallium autometallographic technique to observe changes in neuronal activity in the forebrain of rats following acute carbon monoxide (CO) intoxication. Methods: In order to induce acute CO intoxication, adult Sprague-Dawley rats were exposed to 1100 ppm of CO for 40 minutes, followed by 3000 ppm of CO for 20 minutes. Animals were sacrificed at 30 minutes and 5 days after induction of acute CO intoxication for thallium autometallography. Immunohistochemical staining and toluidine blue staining were performed to observe cellular damage in the forebrain following intoxication. Results: Acute CO intoxication resulted in significant reduction of TI+ uptake in major forebrain structures, including the cortex, hippocampus, thalamus, and striatum. In the cortex and hippocampal CA1 area, marked reduction of TI+ uptake was observed in the cell bodies and dendrites of pyramidal neurons at 30 minutes following acute CO intoxication. There was also strong uptake of TI+ in astrocytes in the hippocampal CA3 area following acute CO intoxication. However, there were no significant histological findings of cell death and no reduction of NeuN (+) neuronal populations in the cortex and hippocampus at 5 days after acute CO intoxication. Conclusion: The results of this study suggest that thallium autometallography can be a new and useful technique for imaging functional changes in neural activity of the forebrain structure following mild to moderate CO intoxication.

• 상하수도학회지
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• 제35권6호
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• pp.455-463
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• 2021

The adsorption process using GAC is one of the most secured methods to remove of phosphate from solution. This study was conducted by impregnating Cu(II) to GAC(GAC-Cu) to enhance phosphate adsorption for GAC. In the preparation of GAC-Cu, increasing the concentration of Cu(II) increased the phosphate uptake, confirming the effect of Cu(II) on phosphate uptake. A pH experiment was conducted at pH 4-8 to investigate the effect of the solution pH. Decrease of phosphate removal efficiency was found with increase of pH for both adsorbents, but the reduction rate of GAC-Cu slowed, indicating electrostatic interaction and coordinating bonding were simultaneously involved in phosphate removal. The adsorption was analyzed by Langmuir and Freundlich isotherm to determine the maximum phosphate uptake(q_m) and adsorption mechanism. According to correlation of determination(R²), Freundlich isotherm model showed a better fit than Langmuir isotherm model. Based on the negative values of q_m, Langmuir adsorption constant(b), and the value of 1/n, phosphate adsorption was shown to be unfavorable and favorable for GAC and GAC-Cu, respectively. The attempt of the linearization of each isotherm obtained very poor R². Batch kinetic tests verified that ~30% and ~90 phosphate adsorptions were completed within 1h and 24 h, respectively. Pseudo second order(PSO) model showed more suitable than pseudo first order(PFO) because of higher R². Regardless of type of kinetic model, GAC-Cu obtained higher constant of reaction(K) than GAC.

• 운동영양학회지
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• 제15권4호
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• pp.163-171
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• 2011

The effects of a high-fat diet and fasting on resting energy expenditure and energy substrate utilization were examined using the method of measuring whole body energy metabolism and oxygen uptake. Eight 4-week old male Sprague-Dawley rats were used for the high-fat diet experiment. Energy metabolism was measured using acrylic metabolic chambers over 24 hours. After 1-week of preliminary feeding, 4 rats were fed a chow diet, whereas the remaining 4 rats were fed a high-fat diet (HF) ad libitum, which contained 40% (w/w, calorie base 60%) more fat than that in the chow diet. The flow rate to measure energy metabolism inside the chamber was controlled at a mean of 3.5 L/min, and five chambers were subjected to measurement. One of the five chambers was used to correct errors by measuring the atmosphere. As a result of 5 weeks of control diet and high-fat diet feeding, body weight of the high-fat diet group tended to increase more than that in the control diet fed group, but the difference was not significant. Oxygen uptake and carbon dioxide production changed as time went on over the 24 hr. The respiratory exchange ratio also changed during the 24 hr, and the difference between the groups was significant. The control group showed significantly more carbohydrate oxidation than that of the high-fat diet fed group. A fasting experiment was conducted using six 7-week old Sprague-Dawley male rats. Energy metabolism measurements were performed using the same method as that used in the high-fat diet experiment; resting metabolism was measured prior to fasting, and a fasting condition began from 9:00 am the next day for 3 days to calculate energy metabolism. Both body weight and 24-hour oxygen uptake decreased significantly as a result of 3-day fasting. Total oxygen uptake in the first day decreased, and declined significantly on day 3 of fasting. Total 24-hour carbon dioxide production decreased significantly over the 3 days. The mean 24-hour respiratory exchange ratio decreased significantly. Additionally, energy expenditure during the dark period (20:00-08:00), which is the active period for rats, decreased significantly with fasting, whereas energy expenditure during the light period (08:00-20:00) did not increase by fasting.

• 한국환경과학회지
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• 제18권12호
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• pp.1411-1416
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• 2009

Several adsorbents were tried to remove the selenium ions from industrial wastewater and the following ascending order of the adsorption performance for the selenium at pH 9 was observed: cation exchange resin < chelate resin < zeolite < brown marine algae < granular activated carbon < anion exchange resin. Initial concentration of selenium(146 mg/L) in industrial wastewater was reduced to 63 mg/L of selenium at pH 9 by neutralization process. The maximum uptake of Se calculated from the Langmuir isotherm with anion exchange resin was 0.091 mmol/g at pH 10 and that with granular activated carbon was 0.083 mmol/g at pH 6. The affinity coefficients of Se ion towards anion exchange resin and granular activated carbon were 3.263 L/mmol at pH 10 and 0.873 L/mmol at pH 6, respectively. The sorption performance of anion exchange resin at the low concentration of Se, namely, was much better than that of granular activated carbon. The Se ions from industrial wastewater throughout neutralization process and two steps of adsorption using anion exchange resin was removed to 97.7%.

• The Korean Journal of Physiology
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• 제22권2호
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• pp.307-318
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• 1988

가토 신장 피질에서 Percoll density gradient방법으로 분리한 basolateral membrane vesicle (BLMV)에서 rapid filtration technique을 이용하여 succinate의 이동 특성을 관찰하였다. $Na^+$은 succinate의 이동을 증가시켜 "overshoot"현상을 보였으며 이러한 효과는 $K^+,{\;}Li^+,{\;}Rb^+,{\;}choline$과 같은 다른 양이온들에 의해 나타나지 않았다. $Na^+$농도변화에 따른 succinate의 이동율은 sigmoid모양을 보였고, $Na^+$에 대한 Hill coefficient는 2.0이었다. soccinate의 이동은 vesicle 내부가 음전압일 때 더욱 증가되었다. BLMV에서 succinate이동은 용액내 pH변화에 따라 영향을 받았으나 brush border membrane vesicle (BBMV)에서는 영향을 받지 않았다. 동력학적 분석결과 succinate의 Km값은 $15.5{\pm}0.94{\;}{\mu}M$이었고 Vmax는 $16.22{\pm}0.25{\;}n{\;}mole/mg{\;}protein/min$이었다. succinate의 이동은 $4{\sim}5$탄소를 가진 dicarboxylate들에 의해 강력하게 억제되었으나 monocarboxylate나 다른 유기음이온들에 의해 영향을 적게 받거나 받지 않았다. succinate의 이동은 DIDS, SITS, furosemide와 같은 음이온 이동 억제제와 harmaline과 같은 $Na^+$ 이동 억제제에 의해 억제되었다. 이들 결과들은 BLMV에서 succinate는 $Na^+$에 의존하여 이동하며 다른 Krebs cycle중간 산물들과 동일한 운반기전을 이용함을 가르킨다. 또한 BLMV에서 succinate의 이동은 그 기질특이성에 있어서 다른 연구자에 의해 보고된 BBMV에서 이동특성과 유사함을 보였다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제24권6호
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• pp.16-25
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• 2019

Anthropogenic polycyclic aromatic hydrocarbons (PAHs) are formed by the incomplete combustion of fuels and industrial waste. PAHs can be widely exposed to the environment (water, soil and groundwater). PAHs are potentially toxic, mutagenic and/or carcinogenic. Fundamental studies such as biota uptake (e.g., earthworm and plant) of PAHs are highly needed. It is necessary to develop alternative ways to evaluate bioavailability of PAHs instead of using living organisms because it is time-consuming, difficult to apply in the field, and also exaction method is tedious and time-consuming. In this study, sorption behaviors of phenanthrene were evaluated to predict the fate of PAHs in soils. Moreover, bioaccumulation of PAHs in an artificially contaminated soil was evaluated using pea plant (Pisum sativum) as a bioindicator. A novel passive sampler, organic-diffusive gradient in thin-film (o-DGT) for PAHs was newly synthesized, tested as a biomimic surrogate and compared with plant accumulation. Sorption partitioning coefficient (K_P) and sorption capacity (K_F) were in the order of natural soil > loess corresponding to the increase in organic carbon content (f_oc). Biota-to-soil accumulation factor (BSAF) and DGT-to-soil accumulation factor (DSAF) were evaluated. o-DGT uptake was linearly correlated with pea plant uptake of phenanthrene in contaminated soil (R²=0.863). The Tenax TA based o-DGT as a biomimic surrogate can be used for the prediction of pea plant uptake of phenanthrene in contaminated soil.

• 한국조경학회지
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• 제29권3호
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• pp.38-45
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• 2001

This study quantified annual $CO_2$, SO$_2$ and NO$_2$ uptake and annual $O_2$ production by trees in Yongin´s urban ecosystem, and explored values of urban tree plantings in atmospheric purification. Woody plant cover was only 7.7% with planting density of 1. trees/100$m^2$, and the tree-age structure was largely characterized by a young, growing tree population. Annual per capita pollutant emissions from fossil fuel consumption were 7.3t/yr for $CO_2$, 7.6kg/yr for SO$_2$, and 26.6kg/yr for NO$_{x}$. Carbon dioxide storage per unit urban area by trees was 13.1t/ha and the economic value for $CO_2$ storage was ￦6.6millions/ha. Annual atmospheric purification was 2.0t/ha/yr for $CO_2$ uptake, 2.0kg/ha/yr for SO$_2$ uptake, 4.0kg/ha/yr for NO$_2$ uptake and 1.5t/ha/yr for $O_2$ production, and the annual economic value for the atmospheric purification was ￦1.5millions/ha/yr. Urbantrees stored an amount of $CO_2$ equivalent to about 3.1% of the total annual $CO_2$ emissions, and annually offset total $CO_2$ emissions by 0.5%. Annual SO$_2$ and NO$_2$ uptake by trees equaled 0.5% of total SO$_2$ emissions and 0.3% of total NO$_{x}$ emissions, respectively. Urban trees also played an important role through producing annually 9.2 of the $O_2$ requirement for Yongin´s total population, despite relatively poor tree plantings. Future active plantings and greenspace enlargement in the study city could enhance the role of atmospheric purification by urban trees. The results from this study are expected to be useful in emphasizing environment benefits of urban trees, and in urging the continuous necessity for tree planting and management budget.get.

• 한국물환경학회지
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• 제20권6호
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• pp.571-576
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• 2004

Since anaerobic/anoxic/oxic process, which is a typical mainstream biological nitrogen and phosphorus removal process, utilizes influent organic matter as an external carbon source for phosphorus release in anaerobic or anoxic stage, influent COD/T-P ratio gives a strong influence on performance of phosphorus removal process. In this study, a bench scale experiment was carried out for SBR process to investigate nitrogen and phosphorus removal at various influent COD/T-P ratio and nitrate loadings of 23~73 and 1.6~14.3g $NO_3{^-}-N/kg$ MLSS, respectively. The phosphorus release and excess uptake in anoxic condition were very active at influent COD/T-P ratios of 44 and 73. However, its release and uptake was not obviously observed at COD/T-P ratio of 23. Consequently, phosphorus removal efficiency was decreased. In addition, the phosphorus release and uptake rate in anoxic condition increased as the nitrate loading decreased. Specific denitrification rate had significantly high correlation with organic materials and nitrate loadings of the anoxic phase too. The rate of phosphorus release and uptake in the anoxic condition were $0.08{\sim}0.94kg\;S-P/kg\;MLSS{\cdot}d$ and $0.012{\sim}0.1kg\;S-P/kg\;MLSS{\cdot}d$, respectively.

• 자원환경지질
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• 제44권6호
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• pp.485-492
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• 2011

활성탄과 자외선을 이용한 시안 저감 연구를 위해 다양한 농도조건 및 넓은 pH 범위에서 배치실험을 수행하였다. 활성탄을 이용한 시안흡착은 시안의 초기농도 2 mg/L 이하에서 매우 효율적인 것으로 나타났으며, 시안 초기농도 3 mg/L 이하에서는 pH 7.0 에서의 흡착이 우수하였고, 그 이상의 시안 초기농도 구간에서는 pH 9.0일 경우 흡착량이 많은 것으로 관찰된다. 전체적인 흡착 패턴을 봤을 때, pH 9.0 에서는 시안의 초기농도가 증가함에 따라 흡착이 증가하는 양상을 보이는 반면 pH 7.0 에서는 흡착이 감소하는 양상을 보였다. 이는 활성탄의 반응성이 pH에 따라 변화하고 있음을 시사한다. 시간에 따른 시안의 흡착 결과, 반응 후 초기 30분 동안 빠른 흡착을 보이나 3시간 이내에 급격히 탈착되며, 그 이후로는 흡착이 다시 증가하여 최대 흡착에 이르는 양상을 보이고 있다. 이는 활성탄을 이용한 시안의 초기 흡착모드가 시간에 따라 변화하고 있음을 나타내고 있다. 탈착실험 결과, 활성탄에 흡착된 총 시안 중 최대 1.5%의 탈착을 일으키는 것으로 나타났다. 그밖에 활성탄과 함백탄광슬러지의 혼합물을 이용한 시안흡착은 0.76 mg/g의 낮은 저감효율을 나타냈다. 자외선에 의해서는 최대 96.6%의 매우 효율적인 저감을 보였으며, 시안의 초기농도가 높아질수록 활성탄을 이용한 시안의 저감보다 많은 양의 시안을 저감시키는 것으로 관찰된다. 이번 실험결과는 활성탄과 자외선 모두가 다양한 조건의 환경에서도 시안저감에 효율적일 수 있다는 것을 보여준다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.317-320
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• 2000

The optimal temperature and pH for both mycelial growth and exe-biopolymer production by Cordyceps millitaris in shake flask culture were found to be $20^{\circ}C$ and 6.0, respectively. Sucrose (4%) and corn steep powder (1%) were the most suitable carbon and nitrogen source for mycelial growth and exo-biopolymer production. The maximum specific growth rate $(0.142h^{-1})$ was achieved when sucrose was used as the sole carbon source. Exo-biopolymer production was increased with the increase in C/N molar ratio concentration, probably due to the facilitated carbon uptake. Under the optimal culture conditions, the maximum mycelial growth exe-biopolymer concentration were reached to around 13.3 g dry cell weigh/l and 3.33 g/l, respectively.