• Korean Journal of Environmental Biology
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• v.38 no.2
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• pp.271-277
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• 2020

Toxicities to many organs caused by humidifier disinfectants have been reported. Recently, humidifier disinfectants have been reported to cause cardiovascular, embryonic, and hepatic toxicities. This study was designed to investigate the toxic mechanism of humidifier disinfectants and compare toxicity in a cellular model and a zebrafish animal model. Because brain toxicity and skin toxicity have been less studied than other organs, we evaluated toxicity in a human dermal cell line and zebrafish under various concentrations of humidifier disinfectants that included polyhexamethyleneguanidine phosphate (PHMG), oligo-[2-(2-ethoxy)-ethoxyethyl-guanidinium-chloride] (PGH) and methylchloroisothiazolinone/methylisothiazolinone (CMIT/MIT). A human dermal fibroblast cell line was treated with disinfectants (0, 2, 4, 6, 8, and 16 mg L^-1) to compare their cytotoxicity. The fewest PHMG-treated cells survived (up to 33%), while 49% and 40% of the PGH- and CMIT/MIT-treated cells, respectively, survived. The quantification of oxidized species in the media revealed that the PHMG-treated cells had the highest MDA content of around 28 nM, while the PGH- and CMIT/MIT-treated cells had 13 and 21 nM MDA, respectively. As for brain toxicity, treatment of the zebrafish tank water with CMIT/MIT (final 40 mg L^-1) for 30 min resulted in a 17-fold higher production of reactive oxygen species (ROS) than in the control. Treatment with PGH or PHMG (final 40 mg L^-1) resulted in 15- and 11-fold higher production, respectively. The humidifier disinfectants (PHMG, PGH, and CMIT/MIT) showed severe dermal cell toxicity and brain toxicity. These toxicities may be relevant factors in understanding why some children have language disorders, motor delays, and developmental delays from exposure to humidifier disinfectants.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.1
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• pp.47-50
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• 2009

Purpose: Presently, any exact standard of radiopharmaceutical doses in pediatric nuclear medicine doesn't exist in the universe. So hospitals are following by manual of vial kit or guidelines of America and Europe based on recommended adult doses adjusted for body mass (MBq/kg) or body surface area (MBq/$m^2$). However, especially for children younger than 1 year and heavier than 50 kg, it's hard to estimate exact dosage for those children. Materials and Methods: In order to obtain objective data of multipliers for pediatric studies, we surveyed 4 major hospitals in Korea. After receiving feedbacks, we changed dosage to multiplier. And we compared multipliers of Korea to America's and Europe's. Results: Most hospitals in Korea are following by body mass formula (MBq/kg). On the other hand, standards don't include proper factors for a child younger than 1 year and heavier than 50 kg. Multipliers for 3 kg children who are injected lower doses than needed are America:0.12, Europe:0.09, Korea:0.05, multipliers for 30 kg children who are injected proper doses are America:0.58, Europe:0.51, Korea:0.45 and multipliers for 60 kg children who are injected more doses than needed are America:0.95, Europe:0.95, Korea:0.91. Conclusions : Through the survey, when calculating doses for children, usually output doses are based on adult doses adjusted for body mass (MBq/kg) but research has shown that standards of all of the compared standards don't reflect exact multipliers for children younger than 1 year and heavier than 50 kg. Therefore, we should give an effort to reduce needless radiation exposure in children by establishing a proper doses standard and also developing better image reconstruction software.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.3 no.2
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• pp.141-151
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• 1993

Blood samples obtained from 200 adults who had visited the "S" general hospital were analyzed to compare the zinc protoporphyrin (ZPP) levels quantified by high performance liquid chromatograph (HPLC) and by hematofluorometer (HF) to investigate the methodological difference if any and the relationship between the levels of blood lead and ZPP among no-lead exposed adults. Also investigated were the distribution of ZPP and protoporphyrin IX (PPIX) concentrations, the establishment of normal levels of blood ZPP and blood lead, and the contribution of age and sex factors to these values. These subjects had no previous occupational exposure to lead. The results obtained were as follows : 1. The mean values of blood lead for male and female subjects were $9.46{\pm}2.44{\mu}g/dl$ and $8.09{\pm}2.17{\mu}g/dl$, respectively. The difference observed in the mean concentrations between male and female subjects was statistically very significant. 2. The mean values of blood ZPP by HPLC for male and female subjects were $15.94{\pm}4.55{\mu}g/dl$ and $22.26{\pm}6.61{\mu}g/dl$, respectively. The difference observed in the mean concentrations between male and female subjects was statistically not significant. The mean values of blood PPIX by HPLC for male and female subjects were $2.51{\pm}1.78{\mu}g/dl$ and $2.81{\pm}1.56{\mu}g/dl$, respectively. The difference observed in the mean concentrations between male and female subjects was statistically not significant. 3. The mean values of blood ZPP by HF for male and female subjects were $28.44{\pm}7.11{\mu}g/dl$ and $37.77{\pm}8.04{\mu}g/dl$, respectively. The difference observed in the mean concentrations between male and female subjects was statistically very significant. 4. No statistically significant correlation was found between the levels of blood ZPP and blood lead. 5. The ratio of ZPP and protoporphyrin IX (PPIX) concentration to erythrocyte protoporphyrin (EP, EP=ZPP+PPIX) concentration was 87.4% and 12.6%, respectively. 6. A statistically very significant correlation was found between the ZPP concentrations determined by HPLC and the values by HF (r=0.7565). The ZPP concentraitons quantified by HF were 1.75 times as high as the values obtained by HPLC. 7. The blood ZPP concentrations quantified by HPLC, HF, and spectrofluorometer (SF) from the blood samples obtained from 14 lead-exposed workers and from 16 no-lead exposed adults showed wide variations. The ZPP concentrations by HF were the highest followed by the levels obtained by SF and by HPLC. In the exposed group, no statistically significant difference was found among three methods of quantifying blood ZPP levels. In the no-lead exposed group, however, statistically significant difference was observed among these methods. The ZPP concentrations by HF were about twice as high as those of by HPLC or by SF. Among three methods of quantifying blood ZPP (HPLC, SF and HF), the results revealed significant difference. Therefore it is suggested that objective methods of quantifying blood ZPP and a system of correcting different ZPP levels be developed by the ministry of Labor.

• Journal of Trauma and Injury
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• v.20 no.2
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• pp.57-64
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• 2007

Purpose: Clinically, acute respiratory distress syndrome (ARDS) occurs within 72 hours after acute exposure of risk factors. Because of its high fatality rate once ARDS progresses, early detection and management are essential to reduce the mortality rate. Accordingly, studies on early changes of ARDS were started, and serum ferritin, as well the as injury severity score (ISS), which has been addressed in previous studies, thought to be an early predictive indicator for ARDSMethods: From March 2003 to March 2005, we investigated 50 trauma patients who were admitted to the intensive care unit in Dongguk University Medical Center, Gyeongju. The patients were characterized according to age, sex, ISS, onset of ARDS, time onset of ARDS, serum ferritin level (posttraumatic $1^{st}\;&\;2^{nd}$ day), amount of transfused blood, and death. Abdominal computed topography was performed as an early diagnostic tool to evaluate the onset of ARDS according to its diagnostic criteria. The serum ferritin was measured by using a $VIDAS^{(R)}$ Ferritin (bioMeriux, Marcy-1' Etoile, France) kit with an enzyme-linked fluorescent assay method. For statistical analysis, Windows SPSS 13.0 and MedCalc were used to confirm the probability of obtaining a predictive measure from the receiver operating characteristics (ROC) curve. Results: The ISS varied from 14 to 66 (mean: 33.8) whereas the onset of ARDS could be predicted with the score above 30 (sensitivity: 90.0%, specificity: 60.0%, p<0.05). On the posttraumatic $1^{st}$ day, the serum ferritin levels were measured to be from 31 mg/dL to 1,200 mg/dL (mean: 456 mg/dL), and the onset of ARDS could be predicted when the value was over 340 mg/dL (sensitivity: 80.0%, specificity: 65.0%, p<0.05). On the posttraumatic $2^{nd}$ day, the serum ferritin levels were measured to be from 73 mg/dL to 1,200 mg/dL (mean: 404 mg/dL), and the onset of ARDS could be predicted when the value was over 627 mg/dL (sensitivity: 60.0%, specificity: 92.5%, p<0.05). The serum ferritin levels and the ISS were significantly higher on the posttraumatic $1^{st}$ and $2^{nd}$ day in the ARDS group, suggesting that they are suitable indices predicting the onset of ARDS, however relationship between the serum ferritin levels and the ISS was not statistically significant. Conclusion: In this study, we discovered increasing serum ferritin levels in multiple- trauma patients on the posttraumatic $1^{st}$ & $2^{nd}$ day and concluded that both the serum ferritin level and the ISS were good predictors of ARDS. Although they do not show statistically significant relationship to each other, they can be used as independent predictive measures for ARDS. Since ARDS causes high mortality, further studies, including the types of surgery and the methods of anesthesia on a large number of patients are essential to predict the chance of ARDS earlier and to reduce the incidence of death.

• Tuberculosis and Respiratory Diseases
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• v.62 no.6
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• pp.492-498
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• 2007

Background: Several lines of evidence suggest that a host's genetic factors influence the outcome of exposure to Mycobacterium tuberculosis. The aim of this study was to determine whether polymorphism in NRAMP1 (natural resistance associated macrophage protein 1) gene is associated with the susceptibility or resistance to tuberculosis infection for patients with drug-sensitive pulmonary tuberculosis (DS-TB) and multi-drug resistant pulmonary tuberculosis (MDR-TB). Methods: Eight genetic polymorphisms of the NRAMP1 gene were investigated in patients suffering with DS-TB (n=100) or MDR-TB (n=102), and in healthy normal controls (NC, n=96). The genetic polymorphisms of NRAMP1 were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Results: The frequency of D543N A/G heterogygotes was significantly higher in the DS-TB subjects than the NCs (OR=2.10, 95% CI: 1.00 to 4.41, p=0.049). The frequency of 823C/T T/C heterozygotes was significantly higher in the DS-TB subjects (OR=2.79, 95% CI: 1.11 to 7.04, p=0.029) and the MDR-TB subject (OR=3.30, 95% CI 1.33 to 8.18, p=0.010) than in the NCs. However, the frequency of these genotypes was not different between the DS-TB and MDR-TB subjects. Conclusion: A significant association was found between NRAMP1 823 C/T polymorphism and pulmonary tuberculosis. This result suggests that NRAMP1 polymorphism may be involved in the development of pulmonary tuberculosis in Koreans.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.3 no.2
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• pp.129-136
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• 1970

As an attempt to determine if the morphological differences between the southern and western oysters are due simply to the local ecological factors or are based on their fundamental genetic nature, oyster seeds produced in 1968 at Tong-Young, Ye-Chun, and Ko-Hung on the south coast and at Kan-Wol-Do on the west coast were cross-transplanted during May of 1969 to compare their growth. The spats were placed in plastic baskets which permitted free water flow through and the baskets hung from a wooden rack located at a tidal zone of less than I hour exposure at a depth chosen to keep the baskets submerged in water at all times. Twice a month the growth of the spats were measured along with the air and water temperature and salinity. The early summer spats, which were $17-240\%$ larger, in size, than the late summer spats at the time of cross-transplantation, grew more slowly than the late summer spats when exposed to identical environmental conditions, shortening the initial gap to a $5-20\%$ level as the first year of the growth phase came to an end in December. The growth of the Kan-Wol-Do spats lagged considerably behind the southern spats at all localities tested, whereas there were no significant differences among the latter groups. This suggests that the morphological differences between southern and western Pacific oysters in Korea are a manifestation of genetic variety and that Pacific oysters cultured along the south coast are of an identical variety as they are commonly believed to be. The seasonal changes in temperature and salinity even during rainy season in both the southern and western coastal areas are well within the range suitable for successful spawning, and spat fall. However, since the results were based on twice-a-month measurements with no data covering the critical period before and after spawning, they can only serve to indicate at best the general pattern of changes in the environmental conditions of each growing area.

• Journal of the Korean Society of Radiology
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• v.14 no.1
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• pp.53-60
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• 2020

The purpose of this study is to identify factors affecting picture quality in Roadmap images, which were studied by varying the dilution rate, collimation field and flow rate of contrast medium. For a quantitative evaluation of the quality of the picture, a 3mm vessel model Water Phantom was self-produced using acrylic, a roadmap image was acquired with a self-produced vascular model Water Phantom, and the SNR(Signal to Noise Ratio) and CNR (Contrast to Noise Ratio) were analyzed. CM:N/S In the study on the change of dilution rate, CM:N/S dilution rate changed to (100%~10%:100%), and the measurement of the roadmap image taken using the vascular model Water Phantom showed that the measurement value of SNR gradually decreased as the N/S dilution rate was increased, and the measurement of CNR was gradually reduced. It was confirmed that the higher the dilution rate of CM:N/S, the lower the SNR and CNR, and also significant image can be obtained at the dilution rate of CM:N/S (100%~70:30%). The study showed the value of SNR and CNR in Roadmap image was increased as the Collimation Field was narrowed to the center of the vascular phantom; the Collimation Field was narrowed to the center of the vessel model by 2cm intervals to 0cm through 12cm. To verify the relationship with Roadmap image and Flow Rate, volume of the autoinjector was kept constant at 15 and the flow rate was gradually increased 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. The value of SNR and CNR of images taken by using water Phantom gradually decreased as the Flow Rate increased, but at Flow Rate 9 and 10, the SNR and CNR value was increase. It was not possible to confirm the relationship with SNR and CNR by ROI mean value and Background mean value. It is considered that further study is needed to evaluate the correlation about Roadmap image and Flow Rate. In conclusion, as the dilution rate of N/S in contrast medium was increased, the value of SNR and CNR was decreased. The narrower the Collimation Field, the higher image quality by increasing value of SNR and CNR. However, it is not confirmed the relationship Roadmap image and Flow Rate. It is considered that appropriate contrast medium concentration to minimize the effects of kidney and proper Collimation Field to improve contrast of image and reduce exposure X-ray during procedure is needed.

• Korean Journal of Agricultural and Forest Meteorology
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• v.11 no.2
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• pp.72-78
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• 2009

The demand for rainfall data in gridded digital formats has increased in recent years due to the close linkage between hydrological models and decision support systems using the geographic information system. One of the most widely used tools for digital rainfall mapping is the PRISM (parameter-elevation regressions on independent slopes model) which uses point data (rain gauge stations), a digital elevation model (DEM), and other spatial datasets to generate repeatable estimates of monthly and annual precipitation. In the PRISM, rain gauge stations are assigned with weights that account for other climatically important factors besides elevation, and aspects and the topographic exposure are simulated by dividing the terrain into topographic facets. The size of facet or grid cell resolution is determined by the density of rain gauge stations and a $5{\times}5km$ grid cell is considered as the lowest limit under the situation in Korea. The PRISM algorithms using a 270m DEM for South Korea were implemented in a script language environment (Python) and relevant weights for each 270m grid cell were derived from the monthly data from 432 official rain gauge stations. Weighted monthly precipitation data from at least 5 nearby stations for each grid cell were regressed to the elevation and the selected linear regression equations with the 270m DEM were used to generate a digital precipitation map of South Korea at 270m resolution. Among 1.25 million grid cells, precipitation estimates at 166 cells, where the measurements were made by the Korea Water Corporation rain gauge network, were extracted and the monthly estimation errors were evaluated. An average of 10% reduction in the root mean square error (RMSE) was found for any months with more than 100mm monthly precipitation compared to the RMSE associated with the original 5km PRISM estimates. This modified PRISM may be used for rainfall mapping in rainy season (May to September) at much higher spatial resolution than the original PRISM without losing the data accuracy.

• Journal of fish pathology
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• v.22 no.1
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• pp.35-44
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• 2009

The potential pathogenicity of Vibrio splendidus biovar II, which was isolated from triploid larvae of pacific oyster with bacillary necrosis and fish pathogenic V. anguillarum were investigated. The 5-day-old larvae infected with V. splendidus biovar II at the dose of $1.81{\times}10^{4}$ CFU/$m\ell$ started to die within 8 hours after exposure and the mortality were reached to 100% in 16 hours. However, $1.13{\times}10^{4-5}$ CFU/$m\ell$ of V. anguillarum caused 5.5-20% mortality of the larvae after 24 hours. The 10-day-old larvae infected with V. splendidus biovar II at the dose of $5.0{\times}10^{5}$ CFU/$m\ell$ showed mortality from 8 hours after challenge and led to a marked mortality of 90.47% after 24 hours. But V. anguillarum at doses of $5.08{\times}10^{3-6}$ CFU/$m\ell$ did not show mortality in the 10-day-old larvae. Therefore V. splendidus biovar II exhibited stronger virulence in 5-day-old larvae than 10-day-old and young oyster. Changes in the concentration of Vibrio in sea water showed that V. anguillarum decreased from $1.13{\times}10^{5}$ CFU/$m\ell$ to 1.7${\times}$105 CFU/$m\ell$ and V. splendidus biovar II increased from $1.81{\times}10^{4}$ CFU/$m\ell$ to $1.7{\times}10^{7}$ CFU/$m\ell$. This strong survival ability of V. splendidus biovar II in seawater was thought as one of the virulence factors against oyster larvae. The mortalities of 5-day-old and 10-day-old oyster larvae were decreased by addition of 30 $\mu{g}/m\ell$ of antibacterial agent(oxytetracycline or streptomycin). These results suggest that bacillary necrosis by V. splendidus biovar II can be occurred in oyster larvae in Korea. And virulence of V. splendidus biovar II is stronger than that of V. anguillarum in oyster larvae causing significant mortality at the density of $10^{4}$ CFU/$m\ell$.

• Journal of Science and Technology Studies
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• v.8 no.1
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• pp.97-129
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• 2008

We are living in the time of high probability of technological risk due to increased rate of technology development and diffusion of new technologies. Resolving uncertainties, the basic attribution of risk, by accumulating knowledge over the risk factors of certain technology is critical to management of technological risk. In many cases of technological risks, high uncertainty of knowledge is commonly mentioned reason for public controversies on risk management. However, the type of technological risk with low social agreement and low uncertainty of knowledge, the main reason for public controversy is absence of social agreement. Public debates on the risks of mobile phones electromagnetic fields(EMF) to human health comes under this category. The knowledge uncertainty on human health effect of mobile phones EMF has been lowered increasingly by accumulating enormous volume of knowledge though scientists have not reached a final conclusion whether it pose a risk to the physical and mental health of the general population or not. In contrast with civil organizations calling for precautionary approach based regulation, the mobile phone industry is cling to the position of no-regulation-needed by arguing no clear evidence to prove health risks of mobile phone EMF has found. In Korea, government set exposure standards based on a measurement called the 'specific absorption rate'(SAR) and require the mobile phone industry to open SAR information to the public by their own decision. From the view of pro-regulation side based on precautionary approach, technology risk managament of mobile phones EMF in Korea is highly limited and formalized one with limited measuring of SAR on head part only and problematic self-regulated opening of information about SAR to the public. As far as the government keeps having priority on protecting interest of mobile phone industry over precautionary regulation of mobile phones EMF, the disagreement between civil organizations and the government will not resolved. The risk of mobile phones EMF to human health have high probability of being underestimated in the rate and damage of risk than objectively estimated ones due to familiarity of mobile phone technology. And this can be the cause of destructive social dispute or devastating disaster. To prevent such disastrous results, technology risk management, which integrating the goals of safety with economic growth in public policy and designing and promoting risk communication, is required.