• Journal of Korean Society of Environmental Engineers
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• v.32 no.12
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• pp.1087-1093
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• 2010

Autotrophic denitrification is known as an effective and economical alternative for heterotrophic denitrification using external carbon sources such as methanol. In this study, we evaluated design and operation parameters for a sulfur denitrification reactor (SDR) treating high strength nitrogen wastewater. The SDR was filled with spherical sulfur media in connected to a pilot-scale nutrient removal process (daily flow rate, $Q=18\;m^3/d$) using moving spongy media. Total nitrogen (TN) concentration of the final effluent was below the 7.0 mg TN/L because nitrate was additionally removed through autotrophic denitrificationin without adding alkalinity (initial alkalinity was $169.4{\pm}20.8\;mg$ $CaCO_3$/L). During the test period, 60~80% of nitrogen in the influent was removed even in low temperature (below $15^{\circ}C$). The alkalinity consumption for nitrate removal in SDR was $4.09{\pm}1.29$ g $CaCO_3/g$ ${NO_3}^-$-N, and the residual alkalinity of influent of SDR was higher than that of theoretical requirements for full conversion of nitrate. The consumption of sulfur was 943.8 g S/d and it was 2.4 times higher than theoretical value (400.1 g S/d) due to abrasion and loss of sulfur media in backwash, etc.

• The Korean Journal of Pharmacology
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• v.19 no.1
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• pp.15-35
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• 1983

Although it has been well known that ventricular fibrillation is the most important complication during hypothermia, much investigation has failed to show the exact nature of the etiology of ventricular fibrillation. Recently, there has been considerable research on the relationship between sympathetic activity and ventricular fibrillation under hypothermia. Cardiac muscle normally contains a certain amount of norepinephrine and the dramatic effect of this catecholamines on the cardiac muscle is well documented. It is, therefore, conceivable that cardiac catecholamines might exert an influence on the susceptibility of heart muscle to tachycardia, ventricular fibrillation and arrhythmia, under hypothermia. Hypothermia itself is stress enough to increase tonus of sympatheticoadrenal system. The normal heart is supplied by an autonomic innervation and is subjected to action of circulating catecholamines which may be released from the heart. If the reaction of the heart associated with a variable amount of cardiac catecholamines is. permitted to occur in the induction of hypothermia, the action of this agent on the heart has not to be differentiated from the direct effects of cooling. The studies presented in this paper were designed to provide further information about the cardio-physiological effects of reduced body temperature, with special reference to the role of catecholamines in ventricular fibrillation. Healthy cats, weighing about 3 kg, were anesthetized with pentobarbital(30 mg/kg) intraperitoneally. The trachea was intubated and the endotracheal tube was connected to a C.F. Palmer type A.C. respirator. Hypothermia was induced by immersing the cat into a ice water tub and the rate of body temperature lowering was $1^{\circ}C$ per 5 to 8 min. Esophageal temperature and ECG (Lead II) were simultaneously monitored. In some cases the blood pH and serum sodium and potassium were estimated before the experiment. After the experiment the animals were killed and the hearts were excised. The catecholamines content of the cardiac muscle was measured by the method of Shore and Olin (1958). The results obtained are summarized as follows. 1) In control animal the heart rate was slowed as the temperature fell and the average pulse rates of eight animals were read 94/min at $31^{\circ}C$, 70/min at $27^{\circ}C$ and 43/min at $23^{\circ}C$ if esophageal temperature. Ventricular fibrillation was occurred with no exception at a mean temperature of $20.3^{\circ}C(21-l9^{\circ}C)$. The electrocardiogram revealed abnormal P waves in each progressive cooling of the heart. there was, ultimately, a marked delay in the P-R interval, QRS complex and Q-T interval. Inversion of the T waves was characteristic of all animals. The catecholamines content of the heart muscle excised immediately after the occurrence of ventricular fibrillation was about thirty percent lower than that of the pre-hypothermic heart, that is, $1.0\;{\mu}g/g$ wet weight compared to the prehypothermic value of $1.41\;{\mu}g/g$ wet weight. The changes of blood pH, serum sodium and potassium concentration were not remarkable. 2) By the adrenergic receptor blocking agent, DCI(2-3 mg/kg), given intramuscularly thirty minutes before hypothermia, ventricular fibrillation did not occur in one of five animals when their body temperature was reduced even to $16^{\circ}C$. These animals succumbed at that low temperature, and the changes of heart rate and loss of myocardial catecholamines after hypothermia were similar to those of normal animals. The actual effect of DCI preventing the ventricular fibrillation is not predictable. 3) Administration of reserpine(1 mg/kg, i.m.) 24 hours Prior to hypothermia disclosed reduced incidence of ventricular fibrillation, that is, six of the nine animals went into fibrillation at an average temperature of $19.6^{\circ}C$. By reserpine myocardial catecholamines content dropped to $0.045\;{\mu}g/g$ wet weight. 4) Bretylium pretreatment(20 mg/kg, i.m.), which blocks the release of catecholamines, Prevented the ventricular fibrillation under hypothermia in four of the eight cats. The pulse rate, however, was approximately the same as control and in some cases was rather slower. 5) Six cats treated with norepinephrine(2 mg/kg, i.m.) or DOPA(50 mg/kg) and tranylcypromine(10 mg/kg), which tab teen proved to cause significant increase in the catecholamines content of the heart muscle, showed ventricular fibrillation in all animals under hypothermia at average temperature of $21.6^{\circ}C$ and the pulse rate increased remarkably as compared with that of normal. Catecholamines content of cardiac muscle of these animals markedly decreased after hypothermia but higher than control animals. 6) The functional refractory periods of isolated rabbit atria, determined by the paired stimulus technique, was markedly shortened by administration of epinephrine, norepinephrine and isoproterenol. 7) Adrenergic beta-blocking agents, such as pronethalol, propranolol and sotalol(MJ-1999), inhibited completely the shortening of refractory period induced by norepinephrine. 8) Pretreatment with either phenoxftenbamine or phentolamine, an adrenergic alphatlocking agent, did not modify the decrease in refractory period induced by norepinephrine. From the above experiment it is possible to conclude that catecholamines play an important role in producing ventricular fibrillation under hypothermia. The shortening of the refractorf period of cardiac muscle induced by catecholamines mar be considered as a partial factor in producing ventriculr fibrillaton and to be mediated by beta-adrenergic receptor.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.2
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• pp.196-205
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• 2008

Variability in vertical ozone and meteorological profiles was measured by 2Z electrochemical concentration cells (ECC) ozonesonde at Bangyi in Seoul ($37.52^{\circ}N$, $127.13^{\circ}E$) during June $6{\sim}9$, 2003 in odor to identify the vertical distribution of ozone and its relationship with the lower-atmospheric structure resulted in the high ozone concentrations near the surface. The eight profiles obtained in the early morning and the late afternoon during the study period clearly showed that the substantial change of ozone concentrations in lower atmosphere(${\sim}5\;km$), indicating that it is tightly coupled to the variation of the planetary boundary layer (PBL) structure as well as the background synoptic flow. All profiles observed early in the morning showed very low ozone concentrations near the surface with strong vertical gradients in the nocturnal stable boundary layer due to the photochemical ozone loss caused by surface NO titration under very weak vertical mixing. On the other hand, relatively uniform ozone profiles in the developed mixing layer and the ozone peaks in the upper PBL, were observed in the late afternoon. It was noted that a significant increase in ozone concentrations in the lower atmosphere occurred with the corresponding decrease of the mixing height in the late afternoon on June 8. Ozone in upper layer did not vertically vary much compared to that in PBL but changed significantly on June 6 that was closely associated with the variation of synoptic flows. Interestingly, heavily polluted ozone layers aloft (a maximum value of 115 ppb around 2 km) were formed early in the morning on 6 through 7 June under dominant westerly synoptic flows. This indicates the effects of the transport of pollutants on regional scale and consequently can give a rise to increase the surface ozone concentration by downward mixing processes enhanced in the afternoon.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.4
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• pp.105-113
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• 2003

Successful operation of a reactor can be accomplished when it is operated at proper D depending on the state of degradation. Operation at high D leads to the washout of biomass in the reactor while operation at low D leads to product inhibition due to the accumulation of excess VFA. These appear to limit the production of hydrogen to reach a higher level. Operation by D control was performed to improve the efficiency of hydrogen fermentation of food waste. Although simple organic matters were rapidly degraded in the early stage (day 1-2), proper VFA concentration and pH values were kept in the reactor at D of $4.5d^{-1}$, which was previously reported to be optimum initial D. High butyrate/acetate (B/A) ratios over 3.2 were obtained. Without D control, the reduction of simple organic matters after day 2 caused the decrease of VFA production and the increase of pH. Hydrogen production also decreased, as microbial proliferation was less than microbial loss by washout. However, the reactor performance was dramatically improved at D control from 4.5 to $2.3d^{-1}$. It showed the highest B/A ratios over 2.0 among the reactors on day 4-7. The second hydrogen peak appeared on day 4, resulting in the highest fermentation efficiency (70.8%) among the reactors. It was caused by the enhanced degradation of slowly degradable matters. The COD removed was converted to hydrogen (19.3%), VFA (36.5%), and ethanol (15.0%). Therefore, the strategy using D control, depending on the state of degradation, was effective in improving the efficiency of hydrogen fermentation.

• Journal of Intelligence and Information Systems
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• v.24 no.3
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• pp.157-176
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• 2018

The purpose of this research is to develop a detection model for companies designated as administrative issue in KOSDAQ market using financial data. Administration issue designates the companies with high potential for delisting, which gives them time to overcome the reasons for the delisting under certain restrictions of the Korean stock market. It acts as an alarm to inform investors and market participants of which companies are likely to be delisted and warns them to make safe investments. Despite this importance, there are relatively few studies on administration issues prediction model in comparison with the lots of studies on bankruptcy prediction model. Therefore, this study develops and verifies the detection model of the companies designated as administrative issue using financial data of KOSDAQ companies. In this study, logistic regression and decision tree are proposed as the data mining models for detecting administrative issues. According to the results of the analysis, the logistic regression model predicted the companies designated as administrative issue using three variables - ROE(Earnings before tax), Cash flows/Shareholder's equity, and Asset turnover ratio, and its overall accuracy was 86% for the validation dataset. The decision tree (Classification and Regression Trees, CART) model applied the classification rules using Cash flows/Total assets and ROA(Net income), and the overall accuracy reached 87%. Implications of the financial indictors selected in our logistic regression and decision tree models are as follows. First, ROE(Earnings before tax) in the logistic detection model shows the profit and loss of the business segment that will continue without including the revenue and expenses of the discontinued business. Therefore, the weakening of the variable means that the competitiveness of the core business is weakened. If a large part of the profits is generated from one-off profit, it is very likely that the deterioration of business management is further intensified. As the ROE of a KOSDAQ company decreases significantly, it is highly likely that the company can be delisted. Second, cash flows to shareholder's equity represents that the firm's ability to generate cash flow under the condition that the financial condition of the subsidiary company is excluded. In other words, the weakening of the management capacity of the parent company, excluding the subsidiary's competence, can be a main reason for the increase of the possibility of administrative issue designation. Third, low asset turnover ratio means that current assets and non-current assets are ineffectively used by corporation, or that asset investment by corporation is excessive. If the asset turnover ratio of a KOSDAQ-listed company decreases, it is necessary to examine in detail corporate activities from various perspectives such as weakening sales or increasing or decreasing inventories of company. Cash flow / total assets, a variable selected by the decision tree detection model, is a key indicator of the company's cash condition and its ability to generate cash from operating activities. Cash flow indicates whether a firm can perform its main activities(maintaining its operating ability, repaying debts, paying dividends and making new investments) without relying on external financial resources. Therefore, if the index of the variable is negative(-), it indicates the possibility that a company has serious problems in business activities. If the cash flow from operating activities of a specific company is smaller than the net profit, it means that the net profit has not been cashed, indicating that there is a serious problem in managing the trade receivables and inventory assets of the company. Therefore, it can be understood that as the cash flows / total assets decrease, the probability of administrative issue designation and the probability of delisting are increased. In summary, the logistic regression-based detection model in this study was found to be affected by the company's financial activities including ROE(Earnings before tax). However, decision tree-based detection model predicts the designation based on the cash flows of the company.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.1
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• pp.1-9
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• 1991

A study was carried out to investigate the composition of rock-forming minerals and mineralogical characteristics of the five major parent rocks in Korea. The identification was done through the analyses of chemical. X-ray diffraction, thermal(DTA, TG), infrared spectroscopic, and microscopic methods. Among these methods, X-ray diffraction was considered to be the most rapid and effective way to identify minerals in the parent rocks. The main rock-forming minerals of the parent rocks were feldspars, quartz, and micas in granite and granite-gneiss, calcite and dolomite in limestone, quartz and calcite in shale, plagioclase and augite in basalt. A small amount of sesquioxides was identified as a accessory mineral by means of DTA from the parent rocks of Weoljeong series(granite) and Cheongsan series(granite-gneiss). The abrasion pH affecting the soil formation ranged from 7.5 to 8.4 in the parent rocks containing ferromagnesian minerals and carbonates. In the granite and granite-gneiss of which the main rock-forming minerals were feldspars and quartz with low content of biotite, the abrasion pH ranged from 6.2 to 6.4. In chemical composition of the parent rocks, Si, AI, and K oxides tented to increase with higher contents of quartz, feldspars, and muscovite, while Fe and Mg oxides with higher content of biotite, chlorite, amphiboles, and augite. Higher ignition loss in limestone and shale resulted in the release of $CO_2$ from calcite and/or dolomite.

• Korean Journal of Soil Science and Fertilizer
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• v.5 no.2
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• pp.39-42
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• 1972

A field experiment was conducted in a moderately well drained paddy field doveloped in a narrow strip of a valley in order to observe changes of potassium requirement in paddy production when lime is applied. The results obtained are as follows; 1. The response of paddy to potassium (K) and lime (L) is represented mathematically as follow; $Y=462.78+11.582K-0.058L-0.768K^2-0.000015L^2+0.2204KL$. It is considered that the increase of potassium reqirement when slaked lime is applied, is partially due to the increased growth of plant accomplished by the improvement of soil conditions such as the reduction of respiration inhibitors and cationic balance in soil solution. 2. An economic analysis of the use of potassium and slaked lime applying the costs, 80 won per kg of paddy, 19 won per kg of potassium and 4 won per kg of slaked lime to the response function above, showed that the slaked lime without potssium brought a large loss, whereas the use of the lime together with potassium increased the profit remarkably. The profit increased when 10kg of potassium per 10 a is applied in addition to 200kg slaked limn, per 10kg is amounted 4,685 won. 3. A linear relationship between the economic optimum dose of potassium (y) and the amount of slaked lime (x) in paddy production, is obtained as follow; $$y=7.48+\frac{2.77}{200}x$$ It is, however, considered that the amount of potassium to he used might differ according to the soil conditions such as the potassium content and cation exchange capicity of the soil.

• Journal of Oral Medicine and Pain
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• v.36 no.4
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• pp.225-234
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• 2011

Tobacco smoking is a major risk factor of systemic health and also impairs oral health, which is related to development of oral cancers, periodontitis, delayed wound healing, tooth loss, failure of implant, etc. Aside from smoking, many other risk factors can be related to oral health and long-term effects of smoking on salivary flow and taste threshold are still in controversy. Authors considered dental students to be an appropriate group with good oral hygiene for a long-term study to reveal effects of smoking on oral health. This study was performed to compare smoking patterns and current oral health conditions between smokers and nonsmokers in dental students prior to long-term evaluation. 192 volunteers (85.7%) of 224 male dental students in Dankook University were evaluated through questionnaires and clinical examination in 2010. Questionnaires included smoking pattern, alcohol use, nicotine dependence, preventive care, psychological profile and clinical examinations comprised assessment of teeth or periodontal status, nicotine pigmentation, salivary flow, electrical taste thresholds and halitosis. From the study, (current) smokers were older, and drank more frequently with more alcohol intake compared to former smokers and nonsmokers(p<0.05). There was no significant difference among them in salivary flow rate, halitosis and electrical taste threshold. However, there was significant difference in DMFT rate, periodontal treatment need, nicotinic pigmentation between smokers and nonsmokers(p<0.05), irrespective of their levels of preventive care. The smokers in this study, who are young dental students with relatively shorter duration of smoking, less use of cigarettes and low level of nicotine dependence, did not reveal significant impairment of oral health. However, their oral health was found to be relatively impaired compared to nonsmokers', which suggests negative effect of smoking on the oral health and a need of smoking cessation.

• Journal of Soil and Groundwater Environment
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• v.13 no.4
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• pp.22-29
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• 2008

To understand environmental characteristics and contamination assessment of the Namsan Park soil in Seoul, we divided the Namsan map into 33 sectors and sampled mixed soil in depth 0${\sim}$15 cm, in 5${\sim}$10 points at the sites. We analyzed soil samples collected at 21 sectors twice on May and September. The results were as follows. The hue color ranges of the Namsan soil were 2.5YR${\sim}$10YR, the value ranges were 1${\sim}$4, the water rates were 3.1${\sim}$22.3 and the Ignition losses were 3.4${\sim}$10.4%. The average concentration of Cu and Pb were determined 3.374 and 15.000 mg/kg, Cd and As showed very low level. The mean concentrations of Zn and Ni were showed 103.290 and 11.649 mg/kg and this amount is not different from the nationalwide mean in 2005. The mean pH showed 5.41. The Zn, Ni and Cd in the soil of the circular road of Namsan showed 1.33, 1.48, 1.46 times higher than the other sector of the Namsan soil. The corelation coefficient between water rate and ignition loss were 0.720 and the correlation coefficient between Cu and Pb, Cu and Zn showed 0.827, 0.694 respectively. There was weak corelationship between pH and Zn. The Uniformity coefficient (Uc) of all the survey sites was determined below 5 in the range of 1.5${\sim}$4.4.

• Journal of Life Science
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• v.19 no.9
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• pp.1226-1231
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• 2009

Enzyme substitution with recombinant phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) is currently being explored for treatment of phenylketonuria (PKU), an autosomal recessive genetic disorder with mutations of the gene encoding phenylalanine-4-hydroxylase (EC 1.14.16.1). However, oral administration of PAL is limited because of proteolytic digestion in the gastrointestinal tract. The aim of this study was to determine the biochemical properties of PAL and delinate the susceptibility of wild-type PAL to pancreatic proteolysis by exploring several mutants, and to develop therapeutic drugs with PAL for PKU. The specific activity of PAL was assayed and its optimal pH, temperature stability, and intestinal protease susceptibility were investigated. Its $V_{max}$ values for phenylalanine and tyrosine were 1.77 and $0.47{\mu}mol$/ min/mg protein, respectively, and its $K_m$ values were $4.77{\times}10^{-4}$ and $4.37{\times}10^{-4}\;M$, respectively. PAL showed an optimal pH at 8.5, corresponding to the average pH range of the small intestine. It showed no loss of activity at $-80^{\circ}C$ for 5 months and possessed 93.4% of its activity under $4^{\circ}C$ for 4 wks. PAL was susceptible to chymotrypsin digestion and, to a lesser extent, to trypsin, elastase, carboxypeptidase A, and B. The trypsin and chymotrypsin cleaving sites were mutated to investigate protection from pancreatic digestion and the specific activities of these mutants were evaluated. The six mutants displayed low specific activities compared to the wild-type, suggesting that the primary trypsin and chymotrypsin cleaving sites may be essential for catalytic reaction. The PAL mutants could therefore be applied as a pretreatment modality without susceptibility to proteolytic attack, however, additional modification for enhancing enzymatic activity is needed to reduce the Phe levels effectively.