• 생명과학회지
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• 제17권10호
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• pp.1414-1418
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• 2007

3가지 농도의 납을 첨가한 토양에서 생장한 애기장대(Arabidopsis thaliana)에서 식물체에 축적된 납의 농도를 조사하였다. 환경부 고시 오염물질 배출기준 농도(1 mg/l)와 10배 높은 농도(10 mg/l) 및 50배 높은 농도(50 mg/l)의 납이 첨가된 토양에서 생장한 식물의 줄기에 축적된 납의 농도는 3가지 농도에서 증가율이 유사하게 나타났으며, 정상식물 줄기에 비하여 평균 약 24% 증가하였다. 3가지 농도의 납이 첨가된 토양에서 생장한 식물의 잎에 축적된 납의 농도는 정상식물 잎에 비하여 평균 약 57% 증가하였으며, 줄기와 마찬가지로 토양에 첨가된 납의 농도 증가에 따라 잎에 축적된 납의 농도는 유의한 차이는 나타나지 않았으며 증가율도 유사하였다. 반면 오염물질 배출기준 농도와 10배 높은 농도의 납이 첨가된 토양에서 생장한 식물의 뿌리에 축적된 납의 농도는 정상식물 뿌리에 비하여 평균 약 114% 증가하였으나, 50배 높은 농도에서는 약 861% 증가하여 줄기나 잎과는 대조적인 결과를 나타내었다. 토양 속에 첨가된 납의 농도가 증가하면 애기장대 식물체 내에 축적된 납의 농도도 증가하였는데, 특히 오염물질 배출기준농도보다 50배 높은 납이 첨가된 토양에서 생장한 식물체내에 축적된 납 농도는 정상식물보다 약 2.6배 증가하였다. 이러한 결과는 토양 속에 오염된 납은 식물의 줄기나 잎보다는 뿌리에 더 많이 축적되며, 줄기와 잎에 축적되는 납 농도는 토양 속에 오염된 납 농도에 비례하여 증가하지 않으나 뿌리에서는 농도에 비례하여 매우 증가하였음을 나타내고 있다.

• 대한기계학회논문집B
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• 제27권9호
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• pp.1282-1289
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• 2003

Transport of a scalar quantity, such as chemical concentration or temperature, is important in many engineering applications and environmental flows. Here we report on results obtained from the large eddy simulations of flow and concentration fields inside the tank performed using a spectral multi-domain technique. The computations were driven by specifying the impeller-induced flow at the blade tip radius (Yoon et al.). This study focused on the concentration development at different molecular diffusivities in a stirred tank operated under turbulent conditions. The main objective of the work presented here is to study the large-scale mixing structure at different molecular diffusivities in a stirred tank by using the large eddy simulation. The time sequence of concentration and flow fields shows the flow dependency of the concentration development. The presence of spatial inhomogenieties is detailed by observing the time variation oflocal concentration at different positions.

• 한국토양비료학회지
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• 제47권6호
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• pp.518-524
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• 2014

Heavy metal pollution in agricultural field near at the abandoned metal mines has been a critical issue in Korea. In particular, bioaccumulation in plants can have detrimental effect on human health. Main objective of this research was to examine arsenic (As) concentration in soil with varied extraction methods and to determine bioaccumulation and biological transfer factor in different crops. Results showed that bioaccumulation ratio of As for total contents in soil was ordered leafy and stem vegetables (1.19%) > fruit bearing vegetables (0.79%) > pulses (0.40%) > root vegetables (0.36%) with different crop species. Among 6 different extraction methods, all of extraction methods showed high correlation ($R^2=0.87-0.97$) except DTPA ($R^2=0.25$) when comparing As concentration in soil extracted with different extractants and As concentration in each crops. Calculated biological transfer factor was ranged 0.002-0.018 depending on crop species. Overall, concentration of As in crops can be varied and best management practice for minimizing bioaccumulation of As should be considered depending on crop species.

• Nuclear Engineering and Technology
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• 제53권6호
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• pp.1955-1963
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• 2021

As the IAEA has applied integrated safeguards and a state level approach to member states, the importance of national inspection has increased. However, the requirements for national inspection for some member states are different from the IAEA safeguards. In particular, the national inspection for the ROK requires on-site U concentration analysis due to a domestic notification. This research proposes an on-site U concentration analysis (OUCA) method for UO₂ pellets using gamma spectroscopy to satisfy the domestic notification requirement. The OUCA method calculates the U concentration of UO₂ pellets using the measured net X-ray counts and declared ²³⁵U enrichment. This research demonstrates the feasibility of the OUCA method using both MCNP simulation and experiment. It simulated and measured the net X-ray counts of different UO₂ pellets with different U concentrations and ²³⁵U enrichments. The simulated and measured net X-ray counts were fitted to polynomials as a function of U concentration and ²³⁵U enrichment. The goodness-of-fit results of both simulation and experiment demonstrated the feasibility of the OUCA method.

• Environmental Engineering Research
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• 제22권3호
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• pp.281-287
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• 2017

The joint effect of different concentrations (0.05-0.375 mmol/L) of $Cd^{2+}$ and various concentrations (50-400 mg/L) of [$C_3mim$][OAc] on the growth and physiology of wheat seedlings were investigated. The toxicity of $Cd^{2+}$ could be significantly reduced by lower concentrations (50-200 mg/L) of [$C_3mim$][OAc]. With higher concentration (${\geq}300mg/L$) of [$C_3mim$][OAc], the reduction became less, and compared to $Cd^{2+}$ stress only, the toxicity of 400 mg/L [$C_3mim$][OAc] increased. As for different $Cd^{2+}$ concentrations, the optimal reduction depends on the balance between the exact concentration of $Cd^{2+}$ and [$C_3mim$][OAc]: With low $Cd^{2+}$ concentration (0.05-0.250 mmol/L) requiring 50 mg/L [$C_3mim$][OAc], it could reach a dynamic equilibrium, while high $Cd^{2+}$ concentration (0.375 mmol/L) requiring 100 mg/L [$C_3mim$][OAc]. The growth and physiological indexes of wheat seedlings show a decrease in toxicity compared to the Cd alone treatment, when the dynamic equilibrium is reached. The concentration of $Cd^{2+}$ in leaf tissues showed that low concentration (50-200 mg/L) of [$C_3mim$][OAc] can reduce the toxicity of $Cd^{2+}$ (0.05-0.375 mmol/L) by decreasing the level of $Cd^{2+}$ concentration in the tissues, whereas the higher concentration (${\geq}300mg/L$) of [$C_3mim$][OAc] can increase the concentration of $Cd^{2+}$.

• Journal of Preventive Medicine and Public Health
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• 제25권4호
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• pp.386-398
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• 1992

In order to study the relationship between life-style and serum lipids level in young adults, the author measured the concentration of serum total cholesterol (TC), triglyceride (TG) and high density lipoprotein cholesterol (HDL-C) and investigated age, relative weight, weekly alcohol intake and daily cigarette smoking through questionnaire in 310 male workers aged 20 to 39, in Ulsan area. The results obtained were as follows: 1. In the factors being able to influence serum lipids level there was negative correlation between age and alcohol intake, and the positive correlation between age and relative weight, alcohol intake and relative weight, alcohol intake and smoking with the strongest correlation between alcohol intake and smoking. 2. In univariate analysis, mean total cholesterol concentration were significantly different according to age, smoking and relative weight: mean triglyceride concentration were significantly different according to relative weight only; mean HCL-C concentration were significantly different according to alcohol intake alone. 3. In non-drinkers, HDL-C concentration of smokers were significantly lower than that of non-smokers but triglyceride concentration of smokers were significant higher. And in drinkers, total cholesterol concentration of smokers was significantly higher than that of non-smokers. 4. In multiple regression analysis, significant independent variables were relative weight, age and smoking in the total cholesterol concentration, and relative weight, age and alcohol intake in the triglyceride concentration, and alcohol intake, relative weight and smoking in the HDL-C concentration. By these independent variables, total variation in each dependent variable was explained 7.9%, 17.6% and 7.4% respectively.

• 미생물학회지
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• 제26권1호
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• pp.44-51
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• 1988

The intracellular free radicals produced at different stages of cell cycle of Saccharomyces cerevisiae ATCC 24858 were investigated by means of electron spin resonance(ESR) spectroscopy. The synchronized cells by repeated starvation and refeeding revealed different ESR spectral pattern compared to that of asynchronized cells. Each spectrum centered at g=2.005, which indicates free radicals. The relative spin concentration was maximat at the end of DNA increase. The variation of the relative spin concentration at each distinct stage of the cell cycle was evaluated in relation to ascorbate concentration, L-galactonolactone oxidase activity, and ascorbate oxidase activity. The highest activities of L-galactonolactone oxidase and ascorbate oxidase were detected just before and at the maximum of relative spin concentration, respectively. And ascorbate concentration fluctuated through each stage of cell cycle with the changes of relative spin concentration, L-galactonolactone oxidase activity, and ascorbate oxidase activity. Thus it is suggested that intracellular free radicals should be related to cell cycle, interacted with ascorbate, and may play an important role in the cell cycle of Saccharomyces cerevisiae.

• Korean Journal of Acupuncture
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• 제20권1호
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• pp.31-38
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• 2003

Effects of Haenggan($LR_2$) and Chungwan ($CV_{12}$) acupuncture on plasma lipid composition were investigated in rat fed high fat diet. Body weight gain showed a tendency to decrease in acupuncture groups and in acupuncture groups, chungwan acupuncture groups showed a lower values than haenggan acupuncture group. Concentrations of plasma triglyceride, free fatty acids showed a decrease in the acupuncture groups. Concentration of plasma lipoprotein showed a tendency to decrease in acupuncture groups, however in the control group and haenggan group, the values showed no significantly different. Plasma glucose concentration showed a low values than control group, in acupuncture groups, the values showed no significantly different. In plasma cholesterol concentration, total cholesterol and LDL-cholesterol showed a tendency to decrease in acupuncture groups, however the values of LDL-cholesterol showed no significantly different in the control group and haenggan group. HDL-cholesterol concentration showed no significantly different in all treatment groups.

• 상하수도학회지
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• 제20권1호
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• pp.147-155
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• 2006

For the further study of the solids flux theory, several researchers have proposed models to predict sludge settling velocity for each different concentration by using sludge indexes, SVI, SSVI and $SSVI_{3.5}$. It is difficult to apply the above models to predict sludge-water interface height in a batch column because sludge settling velocity changes while sludge settle down. While sludge settle down in a batch column, sludge concentration becomes high. The sludge concentration change is one of the most critical causes of the change of sludge settling velocity. Also, sludge concentration change causes of sludge index to change. SVI is more sensitive than SSVI or $SSVI_{3.5}$ to the change of sludge concentration. Each sludge has physical characteristics of its own which makes the settling velocity for each sludge different. The purpose of this study is to establish the correction factors that are able to compensate the errors derived from each different sludge settling characteristic by using sludge indexes, therefore the correction factors are applicable to the model for the change of sludge-water interface height.

• Current Research on Agriculture and Life Sciences
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• 제27권
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• pp.53-58
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• 2009

This experiment was conducted to determine the amount of asparagine content in soybean sprout soup as well as its effect on the regulation of blood alcohol concentration in human body. Asparagine content and alcohol concentration in blood were analyzed using the amino-acid analyzer and alcohol tester, respectively. Asparagine content in soybean sprout soup was highly significantly different among sprout soups sampled from different restaurants, although the boiling time and amount of sprout used were different among the samples. Significantly higher asparagine content was observed in soups with higher amounts of sprouts (2.81% in 500 grams of sprout) and 10 minutes after boiling with other solid ingredients in the soup. Lower concentration of alcohol in blood was recorded in persons with higher body weight. The asparagine+soybean extract (eaten immediately after drink) lowered the blood alcohol concentration significantly followed by only asparagine and control. The blood alcohol concentration after drinking become zero earlier (by 30 minutes), when asparagine+soybean extract or only asparagine was consumed as compared to control.