• Korean Journal of Food Science and Technology
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• v.44 no.2
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• pp.148-154
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• 2012

It was carried out to detect anti-impotence drug-like compounds, sibutramine and their analogues in dietary supplements, which are doubtful whether they include illegal compounds. A total of 51 food products were bought online and have been investigated. The separation was achieved on a C18 column, with the mobile phase made up of water (5 mM sodium hexanesulfonate and 0.1% phosphoric acid) and 95% acetonitrile, at a flow rate of 1.2 mL/min with gradient elution using by HPLC-DAD. The UV signals were monitored at 220 nm and 291 nm. LC-ESI-tandom MS was utilized to confirm that detected compounds in samples are the same as the reference materials. Two nutrient supplement foods and ginseng products were found to contain 1.3-82.1 mg of sildenafil, dimethylthiolsildenafil and pseudovardenafil per serving size. In addition, two other processed products were detected to contain 1.7 and 2.2 mg of didesmethylsibutramine, derived from sibutramine per serving size.

• Korean Journal of Food Science and Technology
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• v.45 no.4
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• pp.391-402
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• 2013

Pesticide residues in agricultural products in Korea were evaluated to create a data base to inform food policy. Pesticide residues were investigated in 17 commodities collected from 9 provinces in 2012. Our analytical method of multiresidue analysis, involved the analysis of individual recovery, linearity, limit of detection, and limit of quantitation of 60 pesticides in six matrices. The pesticides, including acetamiprid and forchlorofenuron, were evaluated in 358 agricultural samples by liquid chromatography/tandem mass spectrometry. Twenty three pesticides were detected from 67 samples. The results showed that the ratio of estimated daily intake to acceptable daily intake was 0.00009-0.0861% by the intake assessment, which means that residual pesticides in agricultural products in Korea are properly controlled.

• Korean Journal of Ecology and Environment
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• v.47 no.3
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• pp.186-193
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• 2014

This study aimed to analyze spatio-temporal trends of phenological characteristics in South Korea by using MODIS EVI. For the phenology analysis, we had applied double logistic function to MODIS time-series data. Our results showed that starting date of phenology seems to have a tendency along with latitudinal trends. Starting date of phenology of Jeju Island and Mt. Sobeak went back for 0.38, 0.174 days per year, respectively whereas, Mt. Jiri and Mt. Seolak went forward for 0.32 days, 0.239 days and 0.119 days, respectively. Our results exhibited the fluctuation of plant phonological season rather than the change of phonological timing and season. Starting date of plant phenology by spatial distribution revealed tendency that starting date of mountain area was late, and basin and south foot of mountain was fast. In urban ares such as Seoul metropolitan, Masan, Changwon, Milyang, Daegu and Jeju, the phonological starting date went forward quickly. Pheonoligcal attributes such as starting date and leaf fall in urban areas likely being affected from heat island effect and related warming. Our study expressed that local and regional monitoring on phonological events and changes in Korea would be possible through MODIS data.

• Microbiology and Biotechnology Letters
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• v.35 no.2
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• pp.158-162
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• 2007

Methicillin-resistant Staphylococcus aureus (MRSA) is one of a major nosocomial pathogen worldwide and the emergence of this strain has become a major clinical problem. This study was performed for 13 hospitals with more than 400 beds in the country by collecting samples including hands and nasal cavities of doctors, nurses, guardians and patients. Also, additional 320 samples of hands and nasal cavities of 160 community resident in different locations and regions were collected. In all of medical environments and community resident, 625 strains of S. aureus were detected. Among 625 strains of S. aureus, 585 strains(93.6%) showed the resistance to at least one kind of antimicrobial and 112 strains (17.9%) showed multi-drug resistance with the resistance to 4 different types of antimicrobial. Total 152 MRSA strains (24.3%) were isolated from medical environment and community resident. In nasal cavity and hand, 49 MRSA (19.4%) and 103 (27.6%) MRSA were isolated, respectively Minimum inhibitory concentration(MIC) test is used to measure for susceptibility of MRSA isolated to oxacillin. At a concentration $16{\mu}g/ml$ of oxacillin, 11 strains were inhibited. 32 strains at $32{\mu}g/ml$, 41 strains at $64{\mu}g/ml$, 3 strains at $128{\mu}g/ml$, 25 stains at $256{\mu}g/ml$ and 40 strains at over $256{\mu}g/ml$ were inhibited. It was considered that medical environment showed higher than livestock and marine environments in MRSA detection rate.

• Journal of Gifted/Talented Education
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• v.25 no.1
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• pp.59-76
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• 2015

The study aimed to investigate elementary school gifted students' hypothesis-generating ability and characteristics of hypotheses and to analyze the correlation between hypothesis-generating ability and meta-cognition. Nineteen students enrolled in a science gifted education center affiliated with a university in 2013 were selected as research subjects. An instrument of open ended items about hypothesis generating was developed and administered to students, and their meta-cognition as well as their preferred science teaching method were examined. Hypotheses generated by students were classified into two categories: scientific and non-scientific hypotheses, and then a closer analysis was conducted on characteristics of non-scientific hypotheses. It was found that 47% (18 out of 38 hypotheses) was scientific ones showing that elementary school gifted students in science in this study presented low level of ability in generating hypothesis. It was also found that non-scientific hypotheses frequently showed characteristics of uncertain in causality or impossible to verify relationships. Furthermore, differences in hypothesis-generating ability and characteristics of hypotheses were appeared in conditions whether inquiry questions and variable identification process were given or not. Students showed high abilities in hypothesis generating and variable identifying when inquiry questions and variable identification process were given. Compared to previous research results, students in the study showed high level of meta-cognition and tendency of utilizing monitoring strategy more than planning and regulating. In ill-structured conditions that students themselves find inquiry questions and identify variables, a significant (p<.05) correlation appeared between hypothesis generating ability and meta-cognition and a high level of correlation between planning and regulating strategies. It was also found that differences existed in hypothesis-generating ability and preferred science teaching methods between students with high level and those with low level of meta-cognition; and students with low level of meta cognition showed difficulties in generating hypothesis and identifying variables.

• Journal of Food Hygiene and Safety
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• v.29 no.2
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• pp.123-130
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• 2014

A simultaneous determination was developed for 9 aminoglycoside antibiotics (amikacin, apramycin, dihydrostreptomycin, gentamicin, hygromycin B, kanamycin, neomycin, spectinomycin, and streptomycin) in meat by liquid chromatography tandem mass spectrometry (LC-MS/MS). Each parameter was established by multiple reaction monitoring in positive ion mode. The developed method was validated for specificity, linearity, accuracy, and precision based on CODEX validation guideline. Linearity was over 0.98 with calibration curves of the mixed standards. Recovery of 9 aminoglycosides ranged on 60.5~114% for beef, 60.1~112% for pork and 63.8~131% for chicken. The limit of detection (LOD) and limit of quantification (LOQ) were 0.001~0.009 mg/kg and 0.006~0.03 mg/kg, respectively in livestock products including beef, pork and chicken. This study also performed survey of residual aminoglycoside antibiotics for 193 samples of beef, pork and chicken collected from 9 cities in Korea. Aminoglycosides were not found in any of the samples.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1B
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• pp.51-60
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• 2006

Water quality improvement in mattress/filter system using porous material like slag from industrial activity and zeolite that has been studied for environment improvement and pollution abatement is very useful in polluted stagnant stream channel. Slag is consisted of CaO, $SiO_2$, $Al_2O_3$ and $Fe_2O_3$. Slag with large specific surface area of porosity has been used such as sludge settling and adsorptive materials. Because slag is porous, it can be used for purification filter. As slag is used as filled materials of mattress/filter system and the system has good advantages for the waste water treatment, water recycling, and the improvement of water quality at the same time and so on. Because zeolite has much advantage of cation exchange, adsorption, catalyst and dehydration characteristics, It is used for environment improvement of livestock farms, treatment of artificial sewage and waste water, improvement of drinking water quality, radioactive waste disposal and radioactive material pollution control. In this study, according to verifying effects of water quality improvement of fill materials by porosity that 38.6%, 45.8% and 49.8% respectively in the stagnant stream channel, water quality monitoring of inflow and outflow was conducted on pH, DO, BOD, COD, SS, T-N and T-P. Mattress/filter system was able to accelerate water quality improvement by biofilter as waste water flows through gap of mattress/filter fill materials and by contact catalysis, absorption, catabolism by biofilm. Mattress/filter system used slag and zeolite forms biofilm easily and accelerates adsorption of organic matter. As a result, mattress/filter system increases water self-purification and accelerates water quality improvement available for stream water clean-up.

• Journal of Food Hygiene and Safety
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• v.38 no.6
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• pp.457-463
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• 2023

To investigate residual pesticide levels in agricultural products contained in Meal-kits, 27 Meal-kit products were collected from marts, Meal-kit shops, and online stores in Incheon City, South Korea. Seventy-six vegetable and thirty-seven mushroom products were analyzed for residual levels of 339 pesticides. Residual pesticides were detected in 23 out of 76 vegetables and were not present in the 37 mushroom products. The residual pesticide detection rate was 20.4% (23/113 cases). The pesticides famoxadone 0.034 mg/kg (standard: 0.01 mg/kg or less, PLS) and fenpyroximate 0.302 mg/kg (standard: 0.01 mg/kg or less, PLS) exceeded their maximum residue levels (MRL). This survey revealed that various types of pesticides remain in agricultural products in Meal-kits. Due to the nature of Meal-kit products, there is no separate standard for residual pesticides in agricultural products. Therefore, continuous monitoring of residual pesticides is necessary.

• Journal of Wetlands Research
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• v.15 no.4
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• pp.555-566
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• 2013

Total maximum daily load enforced in 2004 is a program to evaluate the amount of pollutants by each land use type and manage to meet a target water quality of each waterbody. The many research to calculate runoff load of pollutants by landuse type have been studied. This study was conducted to calculate pollutants EMC, load and unit load in stormwater runoff generated from tomato growing area. Monitoring was conducted about 32 event during 4years and water quality parameters such as BOD, $COD_{Mn}$, TOC, TSS, TN, TP, $NH_3-N$, $NO_3-N$, $PO_4-P$ were analyzed at the laboratory. The average EMC were measured as follows: 9.6 BOD mg/L, 17.2 $COD_{Mn}$ mg/L, 5.5 TOC mg/L, 319.4 TSS mg/L, 4.4 T-N mg/L, 2.6 T-P mg/L, 0.5 $NH_3-N$ mg/L, 0.04 $NO_2-N$ mg/L, 2.6 $NO_3-N$ mg/L, 0.8 $PO_4-P$ mg/L. TN and TP is dichargeed as $NO_3-N$ and particle phosphorus type, respectively.

• Korean Journal of Food Science and Technology
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• v.36 no.1
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• pp.183-187
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• 2004

Radioactivity in foodstuffs was surveyed for reference in amending regulation on the maximum permitted levels of radioactive contamination of foodstuffs. Most domestic and imported (?) foodstuffs were sampled, some domestic items collected around nuclear power plants to compare site-specific contamination. The collected samples were dried and ashed. Radioactivity in foodstuffs was measured using HPGe gamma spectrometer, Cs-137 activity ranged from 0.025-0.053, 0.045-0.500, 0.062-0.105, 0.025-1.151, 0.021-0.145 and 0.046-0.155 Bq/kg-fresh in cereals, pulses, mot vegetables (potato), ginsengs, meat, and marine products, respectively, with imported dried ginseng showing the highest radioactivity, Results reveal radioactivity in foodstuffs collected in 2002 is far below the maximum permitted levels of 370 Bq/kg. No significant differences were observed in radioactivity among sampling sites and between domestic and imported foodstuffs.