• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.4
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• pp.459-464
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• 2017

Biphenyl is used as an intermediate in the production of crop protection products, a solvent in pharmaceutical production, and as a component in the preservation of citrus fruits in many countries. Biphenyl is not authorized for use and also does not have standards or specifications as a food additive in Korea. National and imported food products are likely to contain biphenyl. Therefore, control and management of these products is required. In this study, a simple analytical method was developed and validated using HPLC to determine biphenyl in food. These methods are validated by assessing certain performance parameters: linearity, accuracy, precision, recovery, limit of detection (LOD), and limit of quantitation (LOQ). The calibration curve was obtained from 1.0 to $100.0{\mu}g/mL$ with satisfactory relative standard deviations (RSD) of 0.999 in the representative sample (orange). In the measurement of quality control (QC) samples, accuracy was in the range of 95.8~104.0% within normal values. The inter-day and inter-day precision values were less than 2.4% RSD in the measurement of QC samples. Recoveries of biphenyl from spiked orange samples ranged from 92.7 to 99.4% with RSD between 0.7 and 1.7% at levels of 10, 50, and $100{\mu}g/mL$. The LOD and LOQ were determined to be 0.04 and $0.13{\mu}g/mL$, respectively. These results show that the developed method is appropriate for biphenyl identification and can be used to examine the safety of citrus fruits and surface treatments containing biphenyl residues.

• Tuberculosis and Respiratory Diseases
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• v.50 no.5
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• pp.599-606
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• 2001

Background : Since the advent of AIDS, tuberculosis has become a major public health problem in the western society. Therefore, it is essential that pulmonary tuberculosis be rapidly diagnosed. Light microscopic detection of acid-fast organisms in sputum has traditionally been used for rapidly diagnosing tuberculosis. However positive smears are only observed in about one-half to three-quarters of cases. Studies using PCR for diagnosing pulmonary tuberculosis disclosed several shortcomings suggesting an inability to distinguish between active and treated or inactive tuberculosis. In this study, the clinical significance of a PCR-based rapid technique for detecting Mycobacterium tuberculosis DNA in peripheral blood was investigated. Materials and Methods : From July 1, 1998 through to August 30, 1999, 59 patients with presumed tuberculosis, who had no previous history of anti-tuberculosis medication use within one year prior to this study were recruited and followed up for more than 3 months. AFB stain and culture in the sputum and/or pleural fluids and biopsies when needed were performed. Blood samples from each of the 59 patients were obtained in order to identify Mycobacterium Tuberculosis DNA by a PCR test. Results : 1) Forty five out of 59 patients had a final diagnosis of tuberculosis ; Twenty eight were confirmed as having active pulmonary tuberculosis by culture or biopsy. Four were clinically diagnosed with pulmonary tuberculosis. The other 13 patients were diagnosed as having tuberculous pleurisy (9) and extrapulmonary tuberculosis (4). 2) Fourteen patients showed a positive blood PCR test. The PCR assay correctly identified active tuberculosis in 13 out of 14 patients. The overall sensitivity and specificity of this blood peR assay for diagnosing tuberculosis were 29% and 93%, respectively. The positive predictive value was 93%, the negative predictive value was 29% and the diagnostic accuracy was 44%.3) Six out of 14(43%) patients with blood PCR positive tuberculosis were immunologically compromised hosts. 4) A simple chest radiograph in blood PCR positive tuberculosis patients showed variable and inconsistent findings. Conclusion : A peripheral blood PCR assay for Mycobacterium tuberculosis is not recommended as a screening method for diagnosing active tuberculosis. However, it was suggested that the blood PCR assay could contribute to an early diagnostic rate due to its high positive predictive value.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.3 no.1
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• pp.26-45
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• 1992

This study presents the behavioral and cognitive changes by administration of methylphenidate(MPH) and imipramine(IMI) for the treatment of attention-deficit hyperactivity disorder(ADHD) in $5_{1/2}{\sim}12$ years old children referred to child psychiatric clinics. Behavioral changes are assessed with parent's and teacher's ratings. Drug effects on attention. short-term memory, and impulsivity are evaluated with psychological tests in laboratory. The changes were assessed twice in a 8-week periods. The data were analyzed seperately for 15 subjects each drug using repeated measured analysis of variance(ANOVA). The findings indicates that behavioral and cognitive impairments are improved by both drugs, but impulsivity is not. And MPH is superior to IMI on the improvement of attentional problem ; especially the findings indicates important differences between simple task and complex. perceptual-search task. These data confirm the effectiveness of MPH for treatment of ADHD, also raise questions regarding assessment method of attention and impulsivity as fell as importance of impulsivity in ADHD.

• Tuberculosis and Respiratory Diseases
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• v.42 no.6
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• pp.838-845
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• 1995

The determination of ADA(adenosine deaminase) activity in pleural fluid is useful in differental diagnosis of pleural effusion. The conventional method of determining ADA activity used by Giusti was influenced by contamination of ammonia. Additionally, because Giusti's method was mannual method a determining the ADA activities in sample, was not easily automated. In 1993, Oosthuizen HM with collegues developed simple kinetic method for determining ADA activity. It was reliable and suiable method for automation. In this study, we have measured ADA activity in 162 patients with various pleural effusion by Hitachi 747 autoanalyser using the Oosthuizen kinetic method for the purpuse of determination of new diagnostic cut-off value for the tuberculous effusion and evaluation of the correlation between the conventional method and new automated method. This new method of an enzymatic reaction involves 2, 6-dichlorophenolindophenol dye(DICP), adenosine, xanthine oxidase(XO), and nucleoside phosphorylase(NP). The results were as follows: 1) The mean pleural ADA activity of the tuberculous effusion was $52.53{\pm}16.43\;U/L$ and significantly higher than that of other groups(p<0.001). If the diagnostic cut-off value of pleural ADA activity for tuberculous effusion is above 30 U/L, the sensitivity is 96% and the specificity is 90%. 2) The mean pleural to serum ADA activity ratio of the tuberculous effusion was $2.29{\pm}0.96$ and it was also significantly higher than that of other pleural groups(p<0.001). If the diagnostic cut-off value of pleural to serum ADA activity ratio is 1.5, the sensitivity is 80% and the specificity is 88% in the diagnosis of tuberculous pleural effusion. 3) The new kinetic method is correlates well to Giuisti's conventional method(r=0.971). In conclusion, the new kinetic method described is easily automated and seems to be suitable for the routine determination of ADA activity.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.2
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• pp.112-129
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• 2012

The aim of this study was to provide basic data in managing the project that was carried out on Bulgwangcheon in a nature-friendly way to improve the conditions around the areas, which was brought to completion in 2002, based on changes in ecological characteristics. For this propose, this study examined documents related to the project, compared physical and enviromnental changes before and after the project was conducted and analyzed changes in the stream ecosystem. The result showed that in areas that effluent water was often observed, especially when it rained, the river wall was washed away and vegetation was found damaged. As for actual vegetation, this study compared planting coverage of each section of the research area and actual vegetation charts. The results indicated that Lespedeza spp., Aster koraiensis among mixed seeds that were planted in the reservoir path were almost swept away while Festuca arundinacea dominated the areas. Phragmites communis, Miscanthus sacchariflorns and Salix gracilistyla which had been planted in a small number were also almost washed out though a small number of them were left to form a colony. After examining the topography and structure of the plant community, this study found that areas where mixed seed were planted had changed into two types of vegetation: First type of area is dominated by P and R which are usually raised in apron with abundant floating particles. The second type of area is dominated by dry gramineous plant such as F and A. Areas around low flow channel where Phragmites communis, Miscanthus sacchariflorus and Salix gracilistyla planting construction method is applied was washed away with the width of low flow channel reduced. Though P, M and S formed a small community in some areas around the low flow area, they were in small number and in composition of simple plant species. Two ways were suggested in this study to manage the stream in an ecological way. First, adequate revetment construction methods should be applied by monitoring the flow of the stream as well as considering the flood control of urban streams. Second, target vegetation communities that are suitable for the environment of the stream should be chosen and be plantedconstantly with high density. At the same time, ornamental native plants shouldn't be planted as they have been and disturbing vegetation should be removed.

• Korean Journal of Poultry Science
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• v.43 no.2
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• pp.111-118
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• 2016

Mycotoxins are secondary metabolites produced by molds, such as Aspergillus, Fusarium and Penicillium, that have adverse effects on animals and humans. Aflatoxin, ochratoxin, zearalenone, fumonisin and deoxynivalenol are the mycotoxins of greatest agro-economic importance and cause acute disease called mycotoxicoses. Mycotoxicosis in poultry birds results in decreased meat/egg production, immunosuppressant, and hepatotoxicosis. Some of toxins or their metabolites may be retained in animal or human tissues and induce health problems. This study was designed to develop a sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the simultaneous detection and quantification of mycotoxins, such as aflatoxin $B_1$, aflatoxin $M_1$, ochratoxin A, zearalenone, fumonisin B and deoxynivalenol, in chicken liver and kidney tissues. The mycotoxins were extracted and purified using modified QUECHERS methods, separated by LC and detected by an electrospray ionisation interface (ESI) and tandem MS. Good precision and linearity were observed for most of six mycotoxins. The recovery test for each mycotoxin in liver and kidney tissues mostly indicated good average recovery rates between 80.94% and 98.10% and the coefficient of variation mostly under 13.78%, except for aflatoxin $M_1$ and fumonisin $B_1$. The limit of detection (LOD) for six mycotoxins was $7.6{\sim}145.79{\mu}g/kg$ in liver tissues and $6.07{\sim}197.20{\mu}g/kg$ in kidney tissues. The quantification limits (LOQ) for 6 mycotoxins were in the range $23.04{\sim}441.78{\mu}g/kg$ in liver tissues and $18.40{\sim}597.59{\mu}g/kg$ in kidney tissues, respectively. The developed multi-mycotoxin method in this study permits simultaneous, simple, and rapid determination of several co-existing mycotoxins in chicken liver and kidney tissues.

• Korean Journal of Clinical Laboratory Science
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• v.46 no.3
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• pp.106-110
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• 2014

Obstructive sleep apnea-hypopnea (OSAH) is known to be related to nocturnal blood pressure (BP) and hypertension. The aim of this study was to evaluate the prevalence of hypertension according to the apnea-hypopnea grading. A total of 2,210 adults with snoring and obstructive sleep apnea were referred to our sleep center from July 2009 to May 2013. Clinical blood pressure (BP) was measured before sleeping (bedtime BP) and immediately after waking up in the next morning (morning BP). Subjects were classified into four groups based on the apnea-hypopnea index (AHI) from PSG as follows: control group (n=470) simple snoring and with AHI<5; mild group (n=577) with $AHI{\geq}5$ and <15; moderate group (n=508) $AHI{\geq}15$ and <30; and severe group (n=655) with $AHI{\geq}30$. The differences and correlations between BP and PSG parameters according to the AHI groups were analyzed. Patient's were classified as nomentensive (blood pressure <120/90 mmHg, n=700), prehypertensive (blood pressure < $140-120{\leq}mmHg$, n=1297) hypertensive (blood pressure ${\geq}140/90mmHg$, n=214) according to the office blood pressure measurements. The comparison of sleep parameters showed that OSA groups had a significantly higher stage N1 (control group vs. moderate OSA, severe OSA; $66.4{\pm}30.7$ vs. $85.5{\pm}36.6$, $128.4{\pm}57.3$, p<0.001) and total arousal number (control vs. moderate OSA, severe OSA; $110.7{\pm}47.7$ vs. $150.8{\pm}56.6$, $236.6{\pm}95.8$, p<0.001) compared to control group. The comparison of sleep parameters showed that OSA groups had a significantly lower stage N2 (control group vs. moderate OSA, severe OSA; $172.6{\pm}47.2$ vs. $150.7{\pm}50.5$, $120.3{\pm}57.4$, p<0.001), stage N3 (control group vs. moderate OSA, severe OSA; $38.4{\pm}33.4$ vs. $27.4{\pm}26.0$, $56.1{\pm}27.5$, p<0.001), REM (control group vs. moderate OSA, severe OSA; $64.3{\pm}25.5$ vs. $56.1{\pm}27.5$, $47.3{\pm}25.9$, p<0.001) and mean SaO2% (control group vs. moderate OSA, severe OSA; $90.0{\pm}3.5$ vs. $82.5{\pm}5.5$, $70.0{\pm}8.8$, p<0.001) compared to control group. The Apnea-hypopnea index was significantly higher in OSA groups, increased systolic and diastolic blood pressure than in the nomentensive group (bed time systolic pressure vs. AHI; <120 vs. 120-139, 140-159, >159; $17.5{\pm}18.6$ vs. $24.9{\pm}21.0$, $31.0{\pm}25.7$, $42.3{\pm}31.7$, p<0.001), (bed time diastolic pressure vs. AHI; 60-79 vs. 80-89, 90-99, >99; $19.3{\pm}19.7$ vs. $22.4{\pm}20.3$, $29.8{\pm}23.3$, $38.8{\pm}28.5$, p<0.001). AHI was positively correlated with morning systolic pressure, diastolic pressure, bed time systolic pressure and diastolic pressure (r=0.314, 0.279, 0.233 and 0.200, respectively, p<0.001). We conclude that BMI, Age, neck circumference and AHI increase with the blood pressure.

• Food Engineering Progress
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• v.14 no.3
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• pp.208-216
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• 2010

Lab scale experiments were conducted in order to assess the applicability of $CaCO_{3}$-alginate beads as neutralizer for the high cell density cultivation and prepare the direct vat inoculation cultures of isolated sourdough lactic acid bacteria. With increasing the amount of bead and decreasing the diameter of bead in acidic solution, the neutralizing effect of $CaCO_{3}$-alginate bead became higher. In batch process with $CaCO_{3}$-alginate beads, Lactobacillus amylovorus DU-21 isolated from sourdough showed the highest viable cell counts and optical density in MRS broth. The values of viable cell counts and optical density were 9.996 log CFU/mL and 3.97, respectively. Experiments on the conditions which increase viability during lyophilization were carried out and the following results were obtained; 15% glycerol revealed the high cryoprotective effect on the concentrated cultures during lyophilization among the two cryoprotective agents. Consequently, $CaCO_{3}$-alginate beads and 15% glycerol were found to be useful not only to cultivate Lactobacillus amylovorus DU-21 but also to preserve strain.

• Journal of Food Hygiene and Safety
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• v.34 no.3
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• pp.235-241
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• 2019

An analytical method was developed for the determination of an antibiotic fungicide, kasugamycin, in agricultural products (hulled rice, potato, soybean, mandarin and green pepper) using liquid chromatographytandem mass spectrometry (LC-MS/MS). Samples were extracted with methanol adjusted to pH 13 using 1 N sodium hydroxide, and purified with a HLB (hydrophilic lipophilic balance) cartridge. Linearity of a matrix-matched calibration curve using seven concentration levels, from 0.001 to 0.1 mg/kg, was excellent with a correlation coefficient ($R^2$) of more than 0.9998. The limits of detection (LOD) and quantification (LOQ) of instrument were 0.0005 and $0.001{\mu}g/mL$, respectively, and the LOQ of analytical method calculated as 0.01 mg/kg. The average recoveries at three spiking levels (LOQ, $LOQ{\times}10$, $LOQ{\times}50$, n=5) were in the range of 71.2~95.4% with relative standard deviation of less than 12.1%. The developed method was simple and all optimized results was satisfied with the criteria ranges requested in the Codex guidelines and Food Safety Evaluation Department guidelines. The present study could be served as a reference for the establishment of maximum residue limits (MRL) of kasugamycin and be used as basic data for safety management relative to kasugamycin residues in imported and domestic agricultural products.

• Korean Chemical Engineering Research
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• v.60 no.1
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• pp.93-99
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• 2022

With the rapid development of ultra-small and wearable device technology, continuous electricity supply without spatiotemporal limitations for driving electronic devices is required. Accordingly, Triboelectric nanogenerator (TENG), which utilizes static electricity generated by the contact and separation of two different materials, is being used as a means of effectively harvesting various types of energy dispersed without complex processes and designs due to its simple principle. However, to apply the TENG to real life, it is necessary to increase the electrical output. In addition, stable generation of electrical output, as well as increase in electrical output, is a task to be solved for the commercialization of TENG. In this study, we proposed a method to not only improve the output of TENG but also to stably represent the improved output. This was solved by using the contact layer, which is one of the components of TENG, as an electret for improved output and stability. The utilized electret was manufactured by sequentially performing corona charging-thermal annealing-corona charging on the Fluorinated ethylene propylene (FEP) film. Electric charges artificially injected due to corona charging enter a deep trap through the thermal annealing, so an electret that minimizes charge escape was fabricated and used in TENG. The output performance of the manufactured electret was verified by measuring the voltage output of the TENG in vertical contact separation mode, and the electret treated to the corona charging showed an output voltage 12 times higher than that of the pristine FEP film. The time and humidity stability of the electret was confirmed by measuring the output voltage of the TENG after exposing the electret to a general external environment and extreme humidity environment. In addition, it was shown that it can be applied to real-life by operating the LED by applying an electret to the clap-TENG with the motif of clap.