• Journal of Bio-Environment Control
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• v.4 no.2
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• pp.181-187
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• 1995

This study was conducted to investigate the effect of NH$_4$H$_2$PO$_4$ on pH of the nutrient solution using municipal tap water during hydroponic culture of crisp lettuce (Lactuca sativa var. capitata) seedlings. The composition of starter solution was different from that of supplementary solution. The pH in the nutrient solution was suddenly declined and recovered as the supplementary solution was supplied. The pH of nutrient solution was increased with high temperature and, on the contrary, the EC of nutrient solution was decreased. It shows that plant absorbed nutrients more than water in given solution when the temperature and light was high. After supplying supplementary solution in 1st and End experiment, pH was slowly increased to 7 in NH$_4$H$_2$PO$_4$ 0.25me/$\ell$, but maintained 6.4-6.5 in NH$_4$H$_2$PO$_4$ 3me/$\ell$ and 6me/$\ell$. In 3rd experiment, pH was slowly increased from 6.7 to 7.4 in NH$_4$H$_2$PO$_4$ 0.25me/$\ell$, but decreased from 6-6.5 to 5-5.5 in NH$_4$H$_2$PO$_4$ 3me/$\ell$ and 6me/$\ell$. So it is suggested that the concentration between 0.25 me/$\ell$ and 3 me/$\ell$ by concentration base or the amount of NH$_4$H$_2$PO$_4$ between 1me/6 $\ell$ and 7me/6 $\ell$ by total quantity in solution is appropriate for stabilizing pH in the nutrient solution. Also this experiment suggests that hand operated measurements must be cautious due to the change of pH and EC within a 24-hour cycle.

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.3
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• pp.233-248
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• 2012

The national emission from energy sector accounted for 84.7% of all domestic emissions in 2007. Of the energy-use emissions, the emission from mobile source as one of key categories accounted for 19.4% and further the road transport emission occupied the most dominant portion in the category. The road transport emissions can be estimated on the basis of either the fuel consumed (Tier 1) or the distance travelled by the vehicle types and road types (higher Tiers). The latter approach must be suitable for simultaneously estimating $CO_2$, $CH_4$, and $N_2O$ emissions in local administrative districts. The objective of this study was to estimate 31 municipal GHG emissions from road transportation in Gyeonggi Province, Korea. In 2008, the municipalities were consisted of 2,014 towns expressed as Dong and Ri, the smallest administrative district unit. Since mobile sources are moving across other city and province borders, the emission estimated by fuel sold is in fact impossible to ensure consistency between neighbouring cities and provinces. On the other hand, the emission estimated by distance travelled is also impossible to acquire key activity data such as traffic volume, vehicle type and model, and road type in small towns. To solve the problem, we applied a hierarchical cluster analysis to separate town-by-town road patterns (clusters) based on a priori activity information including traffic volume, population, area, and branch road length obtained from small 151 towns. After identifying 10 road patterns, a rule building expert system was developed by visual basic application (VBA) to assort various unknown road patterns into one of 10 known patterns. The expert system was self-verified with original reference information and then objects in each homogeneous pattern were used to regress traffic volume based on the variables of population, area, and branch road length. The program was then applied to assign all the unknown towns into a known pattern and to automatically estimate traffic volumes by regression equations for each town. Further VKT (vehicle kilometer travelled) for each vehicle type in each town was calculated to be mapped by GIS (geological information system) and road transport emission on the corresponding road section was estimated by multiplying emission factors for each vehicle type. Finally all emissions from local branch roads in Gyeonggi Province could be estimated by summing up emissions from 1,902 towns where road information was registered. As a result of the study, the GHG average emission rate by the branch road transport was 6,101 kilotons of $CO_2$ equivalent per year (kt-$CO_2$ Eq/yr) and the total emissions from both main and branch roads was 24,152 kt-$CO_2$ Eq/yr in Gyeonggi Province. The ratio of branch roads emission to the total was 0.28 in 2008.

• Journal of the Korean Society of School Health
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• v.14 no.1
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• pp.131-143
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• 2001

The primary aim of this dissertation is to contribute to the improvement of methods in physical examination by providing quality information for the current school system and advice for improving status. Present status, controversial points and possible remedies in physical examination were analyzed on a frequency and percentage basis. An $x^2$-test was used to verify the statistics between the results from the examination and each variable. In case of multiple categories of variables, an $x^2$ cs was adopted. Chronological data as well as both total and sampling physical examination data verified the statistics using an $x^2$-test. This thesis is based both on the data from middle school health care specialists in Gyunggi Province and on the analysis of physical examinations reported from local schools to the municipal education agency from 1997 to 1999. The results of the study are as follows: First, according to the survey, only 29.0% of the total schools had their school doctors examine all the students while most of the educational institutions failed to implement the whole process of physical examination on the list. It also turned out that the more students the schools have, the lower the rate of implementation of physical examination by school doctors(p=0.014). Second, the average time a school doctor spends for checkup turned out to be approximately 1.7 minutes per student This means that the quality of the physical examination is not guaranteed in the process. Third, 47.7% of those surveryed say that a dental examination was performed, each taking 21.24 seconds on average. In addition, it shows that some 31.5% wanted to have a task force team for dental checkups at the local health center. Given the fact that dental caries among students is progressively on the rise, the dental health centers that are now set up in some elementary schools should be expanded to cover the whole educational institution in order to raise awareness of the importance of dental care. Fourth, 48.5% of those surveyed say that a comprehensive physical examination should be adopted to promote the health of high schoolers. Since it takes a lot of public funds to implement a comprehensive method, it is essential to make sure that in-depth studies should be based on the frequency and methods of physical examination. Fifth, regarding such diseases among 3rd year middle school students in 1999, statistics shows that there was a slight difference in the prevalence rate of color blindness, and allergic diseases for male students ; and color blindness, hearing disturbance and allergic disease for female students. For those items, however, it is too little to say that there is a significant difference and accordingly it is assumed to be a problem of the measuring process. Sixth, the result of analysis on the sample physical examination and the total physical examination of the year 1999 shows as follows: For male students in the 3rd year of middle school, a slight difference appeared to those students in 11 items including eye problems and eye disease, otitis media, tonsillar hypertrophy, spinal shape, respiratory urinary allergic disease and other abnormal diseases(p<0.05). Particularly, the prevalence rate between students with and without disease was shown to be two times more in the following: eye problems, otitis media, tonsill hypertrophy, allergic diseases, etc. For female students in the 3rd year, prevalence rate showed little difference in 14 items(p<0.05). For items including eye problem, otitis media, tonsill hypertrophy, allergic disease, etc. it was shown that the rate was two times more between students with and without diseases. Physical examinations under the current school system are not producing any fundamental results for the health of the students. Methods and results are not trustworthy. Accordingly, a drastic overhaul of the current practices is needed in frequency, methods and items on the list in order to promote the health of the students. Cost-benefit studies as well as political considerations to ensure the development of efficient methods for physical examination are urgently needed at this moment.

• Journal of Chest Surgery
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• v.31 no.6
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• pp.553-559
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• 1998

Introduction: The most dramatic application of hypothermia in cardiac surgery is in deep hypothermic circulatory arrest(DHCA). Because man in natural circumstances is never exposed to this extreme hypothermic condition, one of the controversial aspects of clinical hypothermia is appropriate acid-base management($\alpha$-stat versus pH-stat). This study aims to compare $\alpha$-stat with pH-stat for: (1) brain cooling and re-warming speed during hypothermia induction and re-warming by cardiopulmonary bypass (CPB); (2) cerebral perfusion, metabolism, and their coupling; and (3) the extent of development of cerebral edema after circulatory arrest, in young pigs. Materials & Methods: Fourteen young pigs were assigned to one of two strategies of gas manipulation. Cerebral blood flow was measured with a cerebral venous outflow technique. After a median sternotomy, CPB was established. Core cooling was initiated and continued until nasopHaryngeal temperature fell below $20^{\circ}C$. The flow rate was set at 2,500 ml/min. Once their temperatures were below $20^{\circ}C$, the animals were subjected to DHCA for 40 mins. During cooling, acid-base balance was maintained according to either $\alpha$-STAT or pH-STAT strategies. After DHCA, the body was re-warmed to normal body temperature. The animals were then sacrificed, and their brains measured for edema. Cerebral perfusion and metabolism were measured before the onset of CPB, before cooling, before DHCA, 15 mins after re-warming, and upon completion of re-warming. Results & Conclusion: Cooling time was significantly shorter with $\alpha$-stat than with pH-stat strategy, while there were no significant differences in rewarming time between the two groups. Nosignificant differences were found in cerebral blood flow, metabolic rate, or flow/ metabolic rate ratio between two groups. Temperature-related differences were significant in cerebral blood flow, metabolic rate, and flow/metabolic rate ratio within each group. Brain water content showed no significant differences between two groups.

• Korean Journal of Microbiology
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• v.47 no.1
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• pp.38-49
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• 2011

Bioaerosols generated from wastewater treatment plants may create health risks for plant workers and nearby residents. To determine the levels of culturable airborne bacteria and fungi in bioaerosols, samples were seasonally collected above and near the aeration tanks of one feces-urine and three sewage treatment plants in Ulsan, Korea with an impaction-type sampler. In the feces-urine treatment plant, concentrations of heterotrophic bacteria were between $1.3({\pm}0.2){\times}10^3$ and $2.6({\pm}1.2){\times}10^4$ MPN/$m^3$ above the aeration tank and between $1.7({\pm}1.0){\times}10^2$ and $7.2({\pm}2.2){\times}10^3$ MPN/$m^3$ near the aeration tank. Coliform bacteria were detected both above and near the aeration tank. In cases of sewage treatment plant, the numbers of heterotrophic bacteria ranged from $1.9({\pm}1.2){\times}10^1$ to $1.8({\pm}1.2){\times}10^4$ MPN/$m^3$ above the aeration tank and from $5.0({\pm}2.8){\times}10^0$ to $6.6({\pm}2.0){\times}10^3$ MPN/$m^3$ near the aeration tank. At reference sites, the concentrations of heterotrophs in ambient air were measured between $7.0{\times}10^0$ and $2.7{\times}10^1$ MPN/$m^3$. When we isolated and tentatively identified heterotrophic bacteria, Pseudomonas luteola was the most dominant species in bioaerosols from wastewater treatment plants, whereas the most abundant one in reference samples was Micrococcus sp. When we measured fungal concentrations in bioaerosols, they were rather similar regardless of sampling locations and seasons, and such genera as Cladosporium, Alternaria, and Penicillium were commonly identified.

• Pediatric Infection and Vaccine
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• v.10 no.1
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• pp.95-101
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• 2003

Objective : To determine the clinical and bacteriologic efficacy and safety of Cefdinir in acute pharyngitis and pharyngotonsillitis caused by group A beta hemolytic streptococci in pediatric patients. Methods : Children aged 3 through 12 years who visited the hospitals enrolled in this study with signs and symptoms of pharyngitis or pharyngotonsillitis since May to December 2002, were taken throat culture and given Cefdinir(12 mg/kg/day, in three divided doses) for 7 days. Two hundred thirty five patients were enrolled and 90 patients who showed positive culture results were followed up for the signs and symptoms during the treatment to determine clinical efficacy. Follow-up culture were done at the end of the study and bacteriologic efficacy was determined Results : Ninety out of 235 patients who visited the hospitals with the signs and symptoms of pharyngitis showed positive growth on throat culture. Seventy nine patients were clinically and microbiologically assessable. The bacteriologic eradication rates of S. pyogenes were 100% in all the children treated with Cefdinir. Clinical cure rates were not different between less than 7 days-treated group(75%) and just 7 days-treated group(98.6%)(P=0.077). Two patients reported adverse reaction during Cefdinir treatment. Antimicrobial sensitivity of Cefdinir against S. pyogenes was 100% with range of MIC being less than 0.5 ${\mu}g/mL$. Conclusion : It seems that Cefdinir is one of reliable and well-tolerated drugs for the treatment of group A beta hemolytic streptococcal pharyngotonsillitis in children. It needs to be investigated short term efficacy in terms of improving drug compliance and impact of economic point of view. We can recognized that still high rate of the erythromycin resistant group A streptococci in our community should be monitored every year.

• Childhood Kidney Diseases
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• v.9 no.2
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• pp.193-200
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• 2005

Purpose : An atrophic renal scar(RS) is one of the underlying causes for childhood hyper tension and chronic renal failure. The risk factors for atrophic renal scar were evaluated. Methods : 41 children, who presented with first febrile urinary tract Infection at the Ewha Womans University Hospital between 1995 and 2003 and had generalized atrophic RS on $^{99m}Tc-DMSA$ renal scan, were retrospectively studied. Atrophic RS was divided into severe atrophic RS(n=14) if relative uptake on renal scan was below 10$\%$, or mild atrophic RS(n=27) if relative uptake on renal scan was between 10-35$\%$. RS was defined as congenital if the scar was detected on the first renal scan, and as acquired if the scar developed on the follow-up renal scan from acute pyelonephritis of the first renal scan. The control group was consisted of randomly selected 41 children with segmental RS. The risk factors for atrophic RS such as the generation time, VUR, gender and ACE gene polymorphism were evaluated. Results : The age distribution of atrophic RS and segmental RS did not differ significantly (P>0.05). The rate of congenital RS in atrophic RS was 61.0$\%$(25/41), which was significantly higher than 9.8$\%$(4/41) of segmental RS(P<0.01). Atrophic RS developed mote frequently in male children(M:F 68.3$\%$ 31.7$\%$) than segmental RS(M:F 41.4$\%$ .58.5$\%$)(P<0.05). Vesicoureteral reflux(VUR) was found in 92.7$\%$(38/41) of 4he atrophic RS, which was significantly higher than 53.7$\%$(22/41) of segmental RS(P<0.05). In children without VUR, the male to female ratio did not differ between atrophic RS and segmental RS(P>0.05) But in children with VUR, there was a higher proportion of males with severe atrophic RS than segmental RS($85.7\%:45.5\%$) ACE gene polymorphism did not differ between the atrophic and segmental RS groups, irrespective of the presence of VUR(P>0.05). Conclusion : Most atrophic RSs were congenital which could not be preventable postnatally and the major risk factors were VUR and the male gender. ACE gene polymorphism was not the significant risk factor for an atrophic RS. (J Korean Soc Pedialr Nephrol 2005;9:193-200)

• Journal of Korean Society of Environmental Engineers
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• v.22 no.11
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• pp.2047-2058
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• 2000

The effects of operating parameters on performance of upflow anaerobic sludge blanket(UASB). anaerobic filter(AF), and two-stage anaerobic sludge bed filter (ASBF) bioreactors in treating swine wastewater were evaluated by operating the lab-scale bioreactors upto hydraulic retention time(HRT) of 1 day and organic loading rate (OLR) of $5.1kg-COD/m^3{\cdot}d$ for 200 days. Swine wastewaters of which characteristics were affected by types of hog raising and seasons contained high concentrations of COD, SS, and ammonia. Inoculation of the bioreactors with waste sludge from anaerobic treatment facility of local municipal wastewater treatment plant was effective in developing biomass in the bioreactors. Acclimation period of the bioreactors with swine wastewaters required approximately 40 days, but that for AF and two-stage ASBF, which were filled with media, was faster than VASB. The bioreactors showed high and stable COD removal efficiency of 77~91% at influent T-N concentrations of 370~800mg/L but low and unstable COD removal efficiency of 24~94% at influent T-N concentrations of 760~1,310mg/L. It is essential to remove ammonia prior to anaerobic treatment since the concentrations of ammonia in swine wastewaters showed toxic effects to methanogenic bacteria. The bioreactors were effective in treating swine wastewaters with COD removal efficiency of 78.9~81.5% and biogas generation rate of $0.39{\sim}0.59m^3/kg-COD_r$ at OLR of $1.1{\sim}2.2kg-COD/m^3{\cdot}d$: however, an increase of OLR by reducing HRT and increasing influent COD caused decrease of COD removal efficiency. The extent of decrease in COD removal efficiency was higher in UASB than AF and two-stage ASBF. AF and two-stage ASBF anaerobic bioreactors were effective in treating varing characteristics of swine wastewaters since they showed high and stable COD removal efficiency at high OLR due to effective retention of biomass by media and staging.

• Korean Journal of Environmental Agriculture
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• v.13 no.2
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• pp.142-150
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• 1994

To investigate differences in Cd and Zn contents of paddy soils and rice plants polluted by the municipal and industrial waste water in the Mangyeong River Area, soil and plant samples were collected at several distances from the main inlet and at different depths of the soil. Soil samples were extracted with $4M-HNO_3$ and plant samples were digested with a mixture of $HNO_3$and $HClO_4$for analyzing heavy metals by atomic absorption spectrophotometry. The contents of Cd and Zn in soils ranged from 0.38 to 1.17 and from 33.8 to 464.6mg kg^{-1}, respectively. The average Cd level in 1990 was less than that in 1982, but the Zn level in 1990 was higher than that in 1982 in general. No variation in Cd contents was observed in soils at the different distances from the source of waste water, but Zn contents in soils were lower with the increasing distances from the source of waste water. A significant correlation was observed among Cd content, OM, available silicate, CEC and $Ca^{++}$. Similar results existed among Zn content of 1982, OM and $Ca^{++}$. The Cd content in subsurface soils of 1992 was significantly correlated with Zn, Cu, and Pb in soils, and the Zn content in soils was significantly correlated with the Cu and Pb in soils, regardless of years. The Cd content in leaf blades of rice was more than seven times higher than that in brown rice. The Zn content in rice was higher than that in leaf blades and in panicle axis. The Cd content in panicle axis and the Zn content in all parts of rice were correlated with Zn, Cu and Pb contents in soils. The Cd and Zn contents in brown rice ranged from 0.10 to 0.90mg $kg^{-1}$ and from 4.2 to 95.9mg $kg^{-1}$ in the Mangyeong River Area, respectively.

• Ocean and Polar Research
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• v.35 no.2
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• pp.69-83
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• 2013

Metal concentrations in creek water, sewer outlets and core sediments were analyzed to identify the potential origin of metal pollution and to evaluate the extent of metal pollution and potential toxicity of Lake Shihwa. Mean concentrations for dissolved metals in creek water and sewer outlets were 1.6~136 times higher than those in the surface seawater of Lake Shihwa. Metal concentrations in creek water from an industrial region were also higher than those from municipal and agricultural regions, indicating that the potential source of metal pollution in the study area might be mainly due to industrial activities. The vertical profiles of metals in core sediments showed an increasing trend toward the upper sediments. Extremely higher concentrations of metals were observed in the vicinity of Banweol industrial complex. The results of a geo-accumulation index indicated that Cu, Zn and Cd were highly polluted. By comparing the sediment quality guidelines such as TEL and PEL, six metals such as Cr, Ni, Cu, Zn, Cd and Pb levels in core sediments nearby industrial complex exceeded the PEL value. Mean PEL quotient (mPELQ) was used to integrate the estimate of potential toxicity for measured metals in the present study. Mean PELQs in core sediments from Lake Shihwa ranged from 0.2~2.3, indicating that benthic organisms nearby the industrial complex may have been adversely affected.