• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.1
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• pp.9-18
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• 2012

Annual power consumption of our country is positioned in the upper percentile in the world, and because the proportion of fossil power generation is high, which ranks the 10th $CO_2$ emission country. In this regard, government has established and is implementing the National Energy Basic Plan to realize to get out of fossilization in energy supply while focusing on securing the technology for renewable energy as well as its commercialization in order to reduce greenhouse gas. Resource recovery technology for deep seawater thermal energy which is one of renewable energies is newly getting attention domestically as well as in overseas for securing resources and environmental improvement as a core technology for multilateral use of marine resources for low carbon and green growth. Economic feasibility analysis was conducted for the research and development as follows on the use of ocean thermal energy conversion and seawater air conditioning. First, in the case of power generation using deep seawater and warm discharge water from ocean thermal energy conversion plant of 1MW level, it is judged that the economic feasibility is insufficient but the feasibility will be significantly improved if we consider not only power generation but also drinking water and certified emission reduction by developing the power plant to the size for commercialization. Second, the economic feasibility for the use of deep seawater as air conditioning for the power plant of 1,000RT level turned out to be very good. Especially, when we consider certified emission reduction, it will be possible to secure sufficient economic feasibility. When we use it in connection with ocean thermal energy conversion, water conversion and agricultural and fishery use, it is judged that economic ripple effect will be significant and therefore it will be necessary to conduct research and development for early commercialization, distribution and diffusion of deep seawater energy.

• The Journal of Korean Society for Radiation Therapy
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• v.18 no.1
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• pp.21-28
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• 2006

Purpose: The purpose of this study is to find a optimal beam spoiler condition on the dose distribution near the surface, when treating a squamous cell carcinoma of the head and neck and a lymphatic region with 10 MV photon beam. The use of a optimal spoiler allows elivering high dose to a superficial tumor volume, while maintaining the skin-sparing effect in the area between the surface to the depth of 0.4 cm. Materials and Methods: The lucite beam spoiler, which were a tissue equivalent, were made and placed between the surface and the photon collimators of linear accelerator. The surface-dose, the dose at the depth of 0.4 cm, and the maximum dose at the dmax were measured with a parallel-plate ionization chamber for $5{\times}5cm\;to\;30{\times}30cm^2$ field sizes using lucite spoilers with different thicknesses at varying skin-to-spoiler separation (SSS). In the same condition, the dose was measured with bolus and compared with beam spoiler. Results: The spoiler increased the surface and build-up dose and shifted the depth of maximum dose toward the surface. With a 10 MV x-ray beam and a optimal beam spoiler when treating a patient, a similer build-up dose with a 6 MV photon beam could be achieved, while maintaining a certain amount of skin spring. But it was provided higher surface dose under SSS of less than 5 cm, the spoiler thickness of more than 1.8 cm or more, and larger field size than $20{\times}20cm^2$ provided higher surface dose like bolus and obliterated the spin-sparing effect. the effects of the beam spoiler on beam profile was reduced with increasing depths. Conclusion: The lucite spoiler allowed using of a 10 MV photon beam for the radiation treatment of head and neck caner by yielding secondary scattered electron on the surface. The dose at superficial depth was increased and the depth of maximum dose was moved to near the skin surface. Spoiling the 10 MV x-ray beam resulted in treatment plans that maintained dose homogeneity without the consequence of increased skin reaction or treat volume underdose for regions near the skin surface. In this, the optimal spoiler thickeness of 1.2 cm and 1.8 cm were found at SSS of 7 cm for $10{\times}10cm^2$ field. The surface doses were measured 60% and 64% respectively. In addition, It showed so optimal that 94% and 94% at the depth of 0.4 cm and dmax respectively.

• Journal of Preventive Medicine and Public Health
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• v.33 no.1
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• pp.1-9
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• 2000

Objectives : This study was carried out to investigate the sources of infection and modes of transmission of an outbreak of shigellosis that occurred among pupils of 'M' primary school and residents near the school in Kyongju from Sept. 24 to Oct. 24, 1998. Methods : The subjects who completed a questionnaire and a rectal swab for microbiologic examinations were 1,534 persons (781 males, 753 females), including 469 pupils of 'M' primary school (268 males, 201 females). Bacteriological examinations of underground water and simple piped water were done. Results : The attack rate of diarrhea was 28.7% in the subjects from Sept.24 to Oct. 24, 1958. There was no difference in attack rate of diarrhea by gender, but it was significantly higher in the pupils of 'M' primary school than others (p<0.01). The attack rate of diarrhea by resident areas was no different to the pupils of 'M' primary school, but was significantly higher in the residents of Mohwa 2 Ri except pupils that 'M' primary school is located in (p<0.01). The distribution of date of onset revealed the exposure date to be Sept, 22 and 23 in consideration of incubation periods and common source outbreak followed propagative spread in the epidemic curve. The major characteristics of diarrhea were watery (89.1%) in nature, $1\sim3$ days (72.5%) in duration, $2\sim3$ times (63.9%) in frequency. The clinical symptoms among the diarrheal cases included abdominal pain (74.1%), fever (56.4%), headache (55.9%), chill (40.4%) and tenesmus (31.4%). Conclusions : The source of infection was estimated to be contaminated underground water and simple piped water caused by leakage from the cess pool. It is highly necessary that the management of drinking water and cess fools should be done thoroughly.

• Journal of Food Hygiene and Safety
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• v.24 no.4
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• pp.291-298
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• 2009

This study was carried out to evaluate the consumer recognition with regard to the safety management for imported foods. In order to evaluate the effect of the prgram on consumer education, the program was practiced for 89 female college students in Seoul, Korea. The participants were given an instruction with materials on imported food safety, including the safety management of imported foods and their distribution. The results showed that the participants achieved a greater understanding of imported foods. In particular, they had firmly grasped the importance of expiration date in selecting imported foods. Before the instruction, 50.6% of total participants blamed the Korean government for the problems arising from imported foods; only 18.0% placed the blame on individuals or businesses importing from foreign countries. After the instruction, 39.3% had blamed the individuals or businesses importing from foreign countries. Furthermore, 36.0% had disapproved of the foods that are imported from China before the instruction, while 32.6% found objectionable the views on the illegally distributed foods; 29.2% criticized the junk foods that target children (after the instruction). In addition, the level of participant satisfaction via-a-vis imported foods safety supervision had improved from $2.76{\pm}1.59$(before the instruction) to $3.37{\pm}1.58$(after the instruction). The results indicate that consumers are concerned with the imported foods that contain adulterated or forbidden substances and the illegally distributed foods from foreign countries. Thus, consistent and informative educational programs on imported food safety could help consumers in choosing safer products, resulting in an improvement in the consumer confidence with respect to imported foods.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.2
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• pp.103-113
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• 2014

Under climate change, it is likely that the suitable area for forage crop cultivation would change in Korea. The potential cultivation areas for italian ryegrass (Lolium multiflorum L.), which has been considered one of an important forage crop in Korea, were identified using the EcoCrop model. To minimize the uncertainty associated with future projection under climate change, an ensemble approach was attempted using five climate change scenarios as inputs to the EcoCrop model. Our results indicated that most districts had relatively high suitability, e.g., >80, for italian ryegrass in South Korea. Still, suitability of the crop was considerably low in mountainous areas because it was assumed that a given variety of italian ryegrass had limited cold tolerance. It was predicted that suitability of italian ryegrass would increase until 2050s but decrease in 2080s in a relatively large number of regions due to high temperature. In North Korea, suitability of italian ryegrass was considerably low, e.g., 28 on average. Under climate change, however, it was projected that suitability of italian ryegrass would increase until 2080s. For example, suitability of italian ryegrass was more than 80 in 10 districts out of 14 by 2080s. Because cold tolerance of italian ryegrass varieties has been improved, it would be preferable to optimize parameters of the EcoCrop model for those varieties. In addition, it would be possible to grow italian ryegrass as the second crop following rice in Korea in the future. Thus, it merits further study to identify suitable areas for italian ryegrass cultivation after rice using new varieties of italian ryegrass.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.4 no.1
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• pp.10-17
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• 2001

Purpose: We measured anti-H. pylori IgG in Korean elementary school children living in Shinchon area of Seoul, Korea to evaluate the influence of environmental living standards on H. pylori infection. Methods: IgG antibodies to H. pylori were measured in plasma using a commercial ELISA kit (GAP IgG Helicobacter pylori, Bio-Rad Laboratories Inc., Hercules, CA, USA). Information on environmental status such as place of birth, parental income, type of housing, number of persons in the household, parents' occupation, family history of peptic ulcer disease and gastric cancer was obtained. Statistical analysis was done by Chi-square and logistic regression test using SPSS $7.0^{TM}$ for Windows. Results: Study subjects consisted of 571 children, and the age distribution ranged from 6.0 to 13.6 years with a mean of $9.6{\pm}1.8$ years. Male-to-female ratio was 1.1:1. The seropositive rates of H. pylori infection ranged from 10.4% in children aged 6 years to 30.9% in 12 year-old group, overall 16.8%. The prevalence of H. pylori infection progressively increased with age, but there was no significant difference in seropositive rates among children in different age groups (p=0.06). Seropositive rates of anti-H. pylori IgG on the basis of gender, place of birth, parental income, type of housing, parents' occupation, family history of peptic ulcer disease and gastric cancer showed no statistically significant difference. Interestingly, however, seropositive rate of anti-H. pylori IgG showed statistical significance in relation to number of persons in the household (p=0.003; Odds ratio 1.50 by logistic regression test). Conclusion: These results suggest that number of persons in the household is the most important factor among environmental living standards, and that risk of H. pylori infection increases by increment of 1.5 times as the number of persons in the household increases by one.

• Pediatric Infection and Vaccine
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• v.25 no.2
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• pp.61-71
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• 2018

Purpose: Research on the clinical role of Staphylococcus aureus as a pathogen in acute gastroenteritis (AGE) in children has been scarce. This study aimed to clarify the prevalence and clinical correlation of S. aureus detection in children with AGE. Methods: Fecal samples were collected from children with symptoms of AGE who visited a secondary hospital between January 2012 and December 2015. The samples were sent to the Seoul Metropolitan Government Research Institute of Public Health and Environment to test for pathogenic organisms. Clinical patterns were analyzed through medical record review. Results: Among the 663 participants, the bacteria detection rate was 26.2% (n=174), the virus detection rate was 29.7% (n=197), and the non-detection rate was 43.1% (n=286). S. aureus was tested positive from 102 cases and was confirmed as a single pathogen in 53 cases. It was the third most common pathogen. The prevalence by age was highest (45.3%) in 0-2 year-olds. Most cases occurred in summer. Symptoms included diarrhea (71.7%), vomiting (67.9%), fever (49.1%), and abdominal pain (37.7%). Only vomiting showed a significant difference between the S. aureus group and the non-detection group (67.9% vs. 43.0%; P=0.001). Among enterotoxins, the higher incidence of vomiting was associated with classical staphylococcal enterotoxins (SEA, SEB, SEC, SED, and SEE) and SEH (P=0.027). Conclusions: S. aureus was the bacteria commonly isolated from children with AGE. Our study identified cases of staphylococcal AGE in children based on fecal samples and confirmed the characteristic symptoms, affected age groups, seasonal distribution, and correlation with enterotoxins.

• Childhood Kidney Diseases
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• v.14 no.2
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• pp.203-209
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• 2010

Purpose : It has been a common medical practice to use prophylactic antibiotics to prevent recurrent urinary tract infections (UTI) in high risk situations such as urinary tract obstruction, vesicoureteral reflux, neurogenic bladder, or urinary stones. But sometimes, we meet difficult situation of breakthrough infections (BI) which might cause new or progressive renal scarring. The clinical characteristics of children contracting breakthrough UTI experienced in a single center were studied. Methods : The study was done retrospectively through medical records of 150 pediatric patients who had been cared in pediatric and urologic clinics of Pusan National University Hospital from Jan. 2001 till June 2006 and had prophylactic antibiotics to prevent recurrent UTI. Results : The starting age of prophylactic antibiotics of 150 patient was 1-76 months, and median age was 5 months. The BI developed 61 times in 43 patients (28.7%), 1.5 times per 100 patient-months. The BI occurred more frequently in patients with higher grade of VUR, and in the cases with abnormal DMSA scan. Co-trimoxazole was more effective than 2nd and 3rd generation cephalosporins to prevent UTI. The distribution of causative organisms was more diverse than usual UTI. The causative organisms were sensitive to the antibiotics used for prophylaxis in 29.5%, and resistant in 59.1%. After experience of BI, 40 percents of patients went to the surgical treatment including endoscopic injection of Deflux, 35% to new antibiotics for prophylaxis, 26% remain on the same antibiotics as the previous one. Conclusion : Based on our study results, preexisting renal scar might be one of the factors which should be considered in favor of early surgical interventions of VUR. Poor compliance and wrong selection of antibiotics such as cephalosporins are important underlying causes of breakthrough UTIs.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.2
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• pp.117-126
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• 1999

Hampyong Bay is a semienclosed and macrotidal bay which opens to the eastern Yellow Sea through a narrow inlet in the southwestern coast of Korea. In order to understand the tidal-flat sedimentation in the semienclosed setting, morphology, sediments, accumulation rate and sea cliff erosion were investigated in the tidal flat of Hampyong Bay. The tidal flat of Hampyong Bay lacks intertidal drainage systems, and generally shows the concave-upward profile whose relief is designated by marked morphological features such as high-tide beaches, intertidal sand shoals and tidal creeks. Surfacial sediments of the tidal flat mainly consist of mud, sandy mud, gravelly mud, gravelly sand and muddy gravel, thus showing the textural characteristics of multimodal grain-size distribution, poorly sorting and positive skewness. The sediments generally coarsen landward due to the increase in coarse fraction content. Sedimentary structures are deeply bioturbated, but parallel lamination and lenticular bedding are locally found in the mudflat near mean low water line. Annual accumulation rates across the tidal flat (along Line SM) average -5.2 cm/yr with a range of -45.8~+4.2 cm/yr, indicating that the tidal flat is erosional. In general, erosion rates of upper and lower tidal flat are higher than those of middle tidal flat. Seasonally, the erosion rates are much higher during spring and winter when dominant wind direction corresponds to the long axis of Hampyong Bay. Sea cliffs are eroded at a rate of 1.4 m/yr. The biggest sea cliff erosion generally occurs 1~2 months later after tidal flats were extensively eroded. Such erosions of tidal Oats and sea cliffs in the semienclosed bay setting are interpreted to be due to wind waves coupled with local sea-level rise.

• Economic and Environmental Geology
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• v.18 no.1
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• pp.1-9
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• 1985

To understand the characteristics of uranium distribution, and the correlation of the uranium content and major constituents in uraniferous black slates from the Jinsan area of Ogcheon Fold Terrain, forty representative specimens were analyzed by mineralogical and radiometric techniques. According to statistical analysis, the uranium has a positive correlation with organic carbon and limonite, but a negative relation to muscovite and other opaques. The relationship with the highest and meaningful correlation is between log uranium and organic carbon. The log uranium-organic carbon correlation coefficient is 0.845 and these two constituents have about 71.4% association. It suggests that the abundance of organic carbon controlled the uranium precipitation. The relationship of organic carbon to log uranium can be expressed by following regression equation log ($U_3O_8{\times}10^4+1$)=-1.3447+2.5599 log (organic carbon). The multiple regression equation of different major components to log uranium is log ($U_3O_8{\times}10^4+1$)=0.77396+ 0.04465 (organic carbon)+0.00574 (quartz)-0.00964 (muscovite)+0.37827 (biotite)-0.02286 (clay substance)+0.01268 (other silicates)+0.1032 (barite)-0.00224 (apatite)+0.01606 (calcite)+0.08258 (hematite)-0.02406 (limonite)-0.01715 (other opaques).