• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.10 no.1
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• pp.1-17
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• 2000

Carcinogen-DNA adduct analysis has potential for biomonitoring the earliest effects of exposure to many chemical carcinogens. They are the covalent reaction products of electrophiles and nucleophilic sites on DNA and the initial damage to DNA induced by many carcinogens. So many researchers begin to use them as biomarker for monitoring the earliest exposure of carcinogens and develop the effective analytical techniques about them. Randerath, Gupta and coworkers(1981, 1982) has also developed a $^{32}P$-postlabelling method as one among them. A major project for biomonitoring workers with carcinogen-DNA adducts is to develop non-invasive samples instead of tissues of target organs such as baldder and lung. This study use the exfoliated urothelial cells in urine for examine benzidine-DNA adducts. The content of exfoliated urothelial cells is not enough to significantly measure DNA content with spectrophotometer, and require the another way. So firstly washing the collected cells with PBS and 70% ethanol and centrifuge them for removing the crystals in urine, which block the isolation of DNA adducts. And then, measure the total nucleotide after $^{32}P$-postlabelling for calculating RAL. $[{\gamma}-^{32}P]ATP$ using for $^{32}P$-postlabelling, can synthesize with $[^{32}P]H_3PO_4$, and reagent and enzyme mixture (RM, EM), which is very economic in case of requiring a lot of them. Chromatography was composed of two steps. First step was to separate adduct ones from unadducted nucleotide, and secondary step was separate each adduct, which were performed with 4 kinds of solvents and different directions on TLC. With this procedure, we measure the DNA adducts in exfoliated urothelial cells of workers who were employed in benzidine and benzidine-dye company. RAL of adducts were $89.0{\times}10^7$ and $57.0{\times}10^7$ in them. In conclusion, we can significantly measure the DNA adduct in exfoliated urothelial cells by using the above $^{32}P$-postlabelling procedures, and use them to be biomonitoring workers who exposed carcinogens.

• Korean Journal of Veterinary Service
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• v.38 no.2
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• pp.127-136
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• 2015

A simultaneous determination method was developed for nine preservatives (benzoic acid, sorbic acid, dehydroacetic acid, methyl-, ethyl-, isopropyl-, propyl-, isobutyl- and butyl-parabens) in sausage by liquid chromatography with electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS). Each parameter was established by multiple reaction monitoring in negative mode. Separation was achieved on a phenyl-hexyl ($2.5{\mu}m$, $2.1{\times}150mm$, Waters) with A-20 mM ammonium acetate containing 0.1% acetic acid in water, B-Acetonitrile as mobile phase with gradient mode at a flow rate of 0.3 mL/min. The developed method was validated for specificity, linearity, accuracy and precision in sausages samples. Linearity was over 0.998 with calibration curve of the mixed standards. The mean recoveries from sausages fortified at the level of 2.0~10.0 mg/L were in range of 98.60~109.16% with RSDs lower than 8.93%. The limits of detection (LOD) and the limits of quantification (LOQ) were in the range between 0.0003~0.085 mg/L and 0.01~0.257 mg/L, respectively. Intra-day precision and inter-day precision were 0.45~6.16% and 2.81~13.33%, respectively. Using presently developed determination method, 33 field sausage samples from Gwangju city in Korea were screened over nine preservatives. As a result, no preservatives were detected in all samples.

• Journal of Distribution Science
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• v.12 no.4
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• pp.31-39
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• 2014

Purpose - This study investigates the following two issues. First, we attempt to find the important determinants of housing investment and to identify their significance rank using survey panel data. Recently, the expansion of global uncertainty in the real estate market has directly and indirectly influenced the Korean housing market; households demonstrate a sensitive reaction to changes in that market. Therefore, this study aims to draw conclusions from understanding how the impact of financial strength of the household is related to house investment. Second, we attempt to verify the effectiveness of diverse indices of financial strength such as DTI, LTV, and PIR as measures to monitor the housing market. In the continuous housing market recession after the global crisis, the government places top priority on residence stability. However, the government still imposes forceful restraints on indices of financial strength. We believe this study verifies the utility of these regulations when used in the housing market. Research design, data, and methodology - The data source for this study is the "National Survey of Tax and Benefit" from 2007 (1st) to 2011 (5th) by the Korea Institute of Public Finance. Based on this survey data, we use panel data of 3,838 households that have been surveyed continuously for 5 years. We sort the base variables according to relevance of house investment criteria using the decision tree model (DTM), which is the standard decision-making model for data-mining techniques. The DTM method is known as a powerful methodology to identify contributory variables for predictive power. In addition, we analyze how important explanatory variables and the financial strength index of households affect housing investment with the binary logistic multi-regressive model. Based on the analyses, we conclude that the financial strength index has a significant role in house investment demand. Results - The results of this research are as follows: 1) The determinants of housing investment are age, consumption expenditures, income, total assets, rent deposit, housing price, habits satisfaction, housing scale, number of household members, and debt related to housing. 2) The impact power of these determinants has changed more or less annually due to economic situations and housing market conditions. The level of consumption expenditure and income are the main determinants before 2009; however, the determinants of housing investment changed to indices of the financial strength of households, i.e., DTI, LTV, and PIR, after 2009. 3) Most of all, since 2009, housing loans has been a more important variable than the level of consumption in making housing market decisions. Conclusions - The results of this research show that sound financing of households has a stronger effect on housing investment than reduced consumption expenditures. At the same time, the key indices that must be monitored by the government under economic emergency conditions differ from those requiring monitoring under normal market conditions; therefore, political indices to encourage and promote the housing market must be divided based on market conditions.

• Clean Technology
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• v.19 no.2
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• pp.156-164
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• 2013

In this study, we analyzed the operational characteristics of a 0.25 MW methanation pilot plant. Isothermal reactor controled the heat released from methanation reaction by saturated water in shell side. Methanation process consisting of isothermal reactor and adiabatic reactor had advantages with no recycle compressor and more less reactors compared with methanation process with only adiabatic reactors. In case that $H_2$/CO ratio of syngas was under 3, carbon deposition occurred on catalyst in tube side of isothermal reactor and the pressure of reactors increased. In case that $H_2$/CO ratio was maintained around 3, no carbon deposition on catalyst in tube side of isothermal reactor was found by monitoring the differential pressure of reactors and by measuring the differential pressure of several of tubes filled with catalyst before and after operating. It was shown that CO conversion and $CH_4$selectivity were over 99, 97%, respectively, and the maximum $CH_4$productivity was $695ml/h{\cdot}g-cat$.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.64-64
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• 2015

Control of plasma processing methodologies can only occur by obtaining a thorough understanding of the physical and chemical properties of plasmas. However, all plasma processes are currently used in the industry with an incomplete understanding of the coupled chemical and physical properties of the plasma involved. Thus, they are often 'non-predictive' and hence it is not possible to alter the manufacturing process without the risk of considerable product loss. Only a more comprehensive understanding of such processes will allow models of such plasmas to be constructed that in turn can be used to design the next generation of plasma reactors. Developing such models and gaining a detailed understanding of the physical and chemical mechanisms within plasma systems is intricately linked to our knowledge of the key interactions within the plasma and thus the status of the database for characterizing electron, ion and photon interactions with those atomic and molecular species within the plasma and knowledge of both the cross-sections and reaction rates for such collisions, both in the gaseous phase and on the surfaces of the plasma reactor. The compilation of databases required for understanding most plasmas remains inadequate. The spectroscopic database required for monitoring both technological and fusion plasmas and thence deriving fundamental quantities such as chemical composition, neutral, electron and ion temperatures is incomplete with several gaps in our knowledge of many molecular spectra, particularly for radicals and excited (vibrational and electronic) species. However, the compilation of fundamental atomic and molecular data required for such plasma databases is rarely a coherent, planned research program, instead it is a parasitic process. The plasma community is a rapacious user of atomic and molecular data but is increasingly faced with a deficit of data necessary to both interpret observations and build models that can be used to develop the next-generation plasma tools that will continue the scientific and technological progress of the late 20th and early 21st century. It is therefore necessary to both compile and curate the A&M data we do have and thence identify missing data needed by the plasma community (and other user communities). Such data may then be acquired using a mixture of benchmarking experiments and theoretical formalisms. However, equally important is the need for the scientific/technological community to recognize the need to support the value of such databases and the underlying fundamental A&M that populates them. This must be conveyed to funders who are currently attracted to more apparent high-profile projects.

• Journal of Food Hygiene and Safety
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• v.31 no.5
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• pp.319-326
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• 2016

Colistin is a last resort antimicrobial agent against multi-drug resistant Gram-negative bacteria. This study was conducted to develop an analytical method to determine colistin in fish and shrimp. The analytes were confirmed and quantified via liquid chromatography-tandem mass spectrometry (LC-MS/MS) in the positive ion mode using multiple reaction monitoring (MRM). The sample was extracted with acidified 5% methanol (containing 0.5% formic acid). Then, solid phase extraction (SPE) was used for cleanup. Matrix-matched calibration curves were linear over the calibration ranges (0.05-1.2 mg/kg) for all the analytes into blank sample with $r^2$ > 0.99. All the values fulfilled the criteria requested by the Codex guidelines. Average recoveries ranged from 85.9% to 107.9%. The repeatability of measurements, expressed as the coefficient of variation (CV, %), was less than 15%. The limit of detection (LOD) was 0.02 mg/kg, and the limit of quantitation (LOQ) was 0.05 mg/kg. This improved method showed higher accuracy and acceptable sensitivity to meet the CAC guideline requirements and is applicable for the analysis of residual colistin (A+B) in fish and shrimp.

• Mass Spectrometry Letters
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• v.5 no.2
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• pp.42-48
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• 2014

A specific and sensitive liquid chromatography-electrospray ionization tandem mass spectrometry method (LC-ESI-MS/MS) was developed and validated for the simultaneous quantification of porphyrins (coproporphyrin, pentacarboxylporphyrin, hexacarboxylporphyrin, heptacarboxylporphyrin, and uroporphyrin) in human plasma and urine. Acidified plasma samples and urine samples were prepared by using liquid-liquid extraction using ethyl acetate and protein precipitation with acetonitrile, respectively. The separation was achieved onto a Synergi Fusion RP column ($150mm{\times}2.0mm$, $4{\mu}m$) with a gradient elution of mobile phase A (0.1% formic acid in 2 mmol/L ammonium acetate, v/v) and mobile phase B (20% methanol in acetonitrile, v/v) at a flow rate of $450{\mu}L$/min. Porphyrins and the internal standard (IS), coproporphyrin I-$^{15}N_4$, were detected by a tandem mass spectrometer equipped with an electrospray ion source operating in positive ion mode. Multiple reaction monitoring (MRM) transitions of the protonated precursor ions and the related product ions were optimized to increase selectivity and sensitivity. The proposed method was validated by assessing selectivity, linearity, limit of quantification (LOQ), precision, accuracy, recovery, and stability. The calibration curves were obtained in the range of 0.1-100 nmol/L and the LOQs were estimated as 0.1 nmol/L for all porphyrins. Results obtained from the validation study of porphyrins showed good accuracy, precision, recovery, and stability. Finally, the proposed method was successfully applied to clinical studies on the autism spectrum disorder (ASD) diagnosis of 203 Korean children.

• Clinical and Experimental Pediatrics
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• v.48 no.11
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• pp.1206-1211
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• 2005

Purpose : Pneumococcal protein vaccine based on pneumococcal surface protein A (PspA) is in development with the potential to offer a broad range of protection against different strains. PspA elicits protection in mice against fatal sepsis as well as carriage and lung infection. This study was performed to investigate the frequency of PspA families among Streptococcus pneumoniae recovered from Korean children and adults. Methods : A total of 89 pneumococcal isolates was included in the study. They were capsule serotyped by the slide agglutination assay with commercial antisera. PspA families were determined with polymerase chain reaction using the pair of primers for family 1 and family 2. Results : Seventeen pneumococcal serotypes were found in a total of 89 isolates. PspA typing was able to ascertain 79 of the 89 isolates (88.8 percent). Among these, 20 (22.5 percent) isolates were family 1 PspA, 59 (66.3 percent) were family 2. Moreover, because 9 (10.1 percent) isolates were of positive reactions for both, families 1 and 2 primers, the potential coverage of PspA vaccine was 98.9 percent. PspA families were not associated with age group, source of isolates, or penicillin susceptibility. However, the relative distribution of family 1 isolates to family 2 isolates was significantly different over capsular serotypes. Conclusion : The finding that 98.9 percent of Korean isolates belonging to PspA families 1 and 2 support the hypothesis that a human PspA vaccine covering a few PspA families could be broadly effective. The monitoring of the PspA families derived from large population-based isolates will be necessary in the context of vaccine development.

• Journal of Preventive Medicine and Public Health
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• v.28 no.2 s.50
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• pp.526-541
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• 1995

This study was conducted to estimate the validity of reverse transcriptase-polymerase chain reaction(RT-PCR) compared to enzyme immunoassay(EIA) for the detection of hepatitis C virus (HCV) infection. EIA for antibody to HCV(anti-HCV) and RT-PCR for HCV was executed on the subjects from Pusan and Kyungnam area with questionnaire survey to collect some relating factors of HCV infection. As the result from 617 cases, the prevalence of HCV infection was 1.5% by EIA and 3.7% by RT-PCR(p<0.05), and the age standardized rate was 1.7% and 3.4% by EIA and RT-PCR, respectively. The prevalence of hepatitis B surface antigen(HBsAg) was 6.8% by enzyme linked immunosorbent assay(ELISA) and the age standardized rate was 7.7%. It was the higher in male group comparing to female group(p<0.01). Both of the prevalence of HCV and HBsAg were higher in elevated asparate aminotransferase(AST) and alanine aminotransferase (ALT) group than in normal AST and ALT group(p<0.01). There was no specific risk factor of HCV infection. Though the degree of agreement of EIA and RT-PCR by gamma statistics was 97.2%, it showed a significant difference between the two methods(p<0.01). For the detection of HCV infection, positive predictive value of EIA was 66.7% and negative predictive value of EIA was 97.2%. This study suggests that negative result to anti-HCV by EIA didn't mean the free state of HCV infection, therefore it would be helpful that further monitoring for HCV infection by RT-PCR in the case of elevated AST and ALT and/or clinically suspected.

• Journal of Pharmaceutical Investigation
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• v.39 no.1
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• pp.65-71
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• 2009

The aim of the present study was to evaluate the bioequivalence of two domperidone maleate tablets, Motilium-$M^{(R)}$ Tablet (Janssen Korea Ltd., reference product) and $Toriem^{(R)}$ Tablet (Daewon Pharm. Co., Ltd., test product). Domperidone was extracted by liquid-liquid extraction using tert-butyl methyl ether and separated in less than 3 min on $C_{18}$ reverse-phase column using an isocratic elution. A tandem mass spectrometer, as detector, was used for quantitative analysis in positive mode by a multiple reaction monitoring mode to monitor the m/z $426.1{\rightarrow}119.1$ and the m/z $837.4{\rightarrow}158.2$ transitions for domperidone and the internal standard (roxithromycin), respectively. Calibration curves, from $0.05{\sim}50$ ng/mL of domperidone, showed correlation coefficients (r) higher than 0.9941. Intra day and inter day precision (C.V. %) for quality control were ranged from 10.04 to 16.09% and from 10.87 to 18.69%, respectively. The lower limit of quantification (LLOQ) of domperidone was 0.05 ng/mL. The method described is precise and sensitive and has been successfully applied to the study of bioequivalence of domperidone in 24 healthy Korean volunteers. Twenty-four healthy male Korean volunteers received a single dose of each medicine ($2{\times}12.72\;mg$ domperidone maleate) in a $2{\times}2$ crossover study. There was a one-week washout period between the doses. Plasma concentrations of domperidone were monitored for over a period of 24 hr after the administration. $AUC_{0-t}$ (the area under the plasma concentration-time curve) was calculated by the linear trapezoidal rule. $C_{max}$ (maximum plasma drug concentration) and $T_{max}$ (time to reach $C_{max}$) were compiled from the plasma concentration-time data. The 90% confidence intervals for the log transformed data were within acceptable range of log 0.8 to log 1.25 (e.g., $log\;0.92{\sim}log\;1.05$ for $AUC_{0-t}$, $log\;0.81{\sim}log\;1.05$ for $C_{max}$). The major parameters, $AUC_{0-t}$ and $C_{max}$ met the criteria of KFDA for bioequivalence indicating that $Toriem^{(R)}$ tablet is bioequivalent to Motilium-$M^{(R)}$ tablet.