• Korean Journal of Environmental Agriculture
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• v.29 no.2
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• pp.165-175
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• 2010

A gas chromatographic (GC) method was developed to determine residues of captan, folpet, captafol, and chlorothalonil, known as broad-spectrum protective fungicides for the official purpose. All the fungicide residues were extracted with acetone containing 3% phosphoric acid from representative samples of five agricultural products which comprised rice, soybean, apple, pepper, and cabbage. The extract was diluted with saline, and dichloromethane partition was followed to recover the fungicides from the aqueous phase. Florisil column chromatography was additionally employed for final cleanup of the extracts. The analytes were then determined by gas chromatography using a DB-1 capillary column with electron capture detection. Reproducibility in quantitation was largely enhanced by minimization of adsorption or thermal degradation of analytes during GLC analysis. Mean recoveries generated from each crop sample fortified at two levels in triplicate ranged from 89.0~113.7%. Relative standard deviations (RSD) were all less than 10%, irrespective sample types and fortification levels. As no interference was found in any samples, limit of quantitation (LOQ) was estimated to be 0.008 mg/kg for the analytes except showing higher sensitivity of 0.002 mg/kg for chlorothalonil. GC/Mass spectrometric method using selected-ion monitoring technique was also provided to confirm the suspected residues. The proposed method was reproducible and sensitive enough to determine the residues of captan, folpet, captafol, and chlorothalonil in agricultural commodities for routine analysis.

• Journal of Applied Biological Chemistry
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• v.57 no.1
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• pp.47-51
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• 2014

The stems of Juncus effusus were extracted with 70% aqueous ethanol and the concentrated extract was partitioned with ethyl acetate, n-butanol and $H_2O$, successively. Two compounds were isolated from the ethyl acetate fraction through the repeated silica gel and Sephadex LH-20 column chromatographies. According to the results of physico-chemical and spectroscopic data including NMR and IR, the chemical structures of the compounds were determined as dehydroeffusol (1) and effusol (2). Dehydroeffusol and effusol exhibited potent scavenging activity for DPPH and ABTS radicals with the $IC_{50}$ values as $130{\pm}3.21$ and $79{\pm}1.53{\mu}M$ in DPPH assay, and as $39{\pm}3.51$ and $24{\pm}2.73{\mu}M$ in ABTS assay, respectively. The compounds also significantly inhibited the proliferation of human cancer cell lines, AGS and A549.

• Journal of Life Science
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• v.19 no.1
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• pp.138-146
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• 2009

Garlic (Allium sativum) are an agronomically important genus because of their sulfur flavour components. The majority of the volatiles flavour principles are generated through the enzymatic hydrolysis of the non-volatile organosulfur compounds. However, these compounds may be possible sources of new novel bioacuve and therapeutic principles. Garlic has strong antioxidant activity, and epidemiological studies support the fad that diets rich of garlic may prevent some of the chronic diseases. The health cares of garlic likely arise from a wide variety of components, which may work synergistically. The chemical changes of garlic composition makes it plausible that a variation in processing can lead to acquisition of differential chemical compositions of garlic products. Especially highly unstable allicin can easily disappear during processing and are quickly transformed into a various organosulfur compounds. Various supplements of garlic, particularly aged garlic extract (AGE), are known to possess a promising antioxidant potential and are effective in prevention of chronic diseases because of the bioactive constituents. Although all of active ingredients of AGE are not elucidated, water-soluble components of AGE, including S-allylcysteine, S-allylmercaptane, steroid saponins, tetrahydro-${\beta}$-carboline derivatives, and fructosyl-arginine, appears to be associated with the pharmacological effects of AGE. Consequently, the allicin free garlic components such as S-allylcysteine, S-allylmercaptane, steroid saponins, tetrahydro-${\beta}$-carboline derivatives, and fructosyl-arginine can be applicable to standardization of the quality of commercial garlic products. This review provides an insight into garlic's biomarkers and presents evidence that they may either prevent or delay chronic disease associated with aging.

• Korean Journal of Pharmacognosy
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• v.49 no.2
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• pp.145-154
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• 2018

Aconiti Kusnezoffii Tuber has been traditionally used to treat the symptoms of rheumatoid arthritis and joint pain. The main constituents are diterpenoid alkaloids such as benzoylmesaconine, benzoylaconine, mesaconitine, aconitine, and hypaconitine. In Korea, Aconiti Kusnezoffii Tuber is officially defined as the tubers of Aconitum kusnezoffii Reichb., A. ciliare Decasisne, and A. triphyllum Nakai. On the other hand, only the tuber of A. kusnezoffii is to be used in China. In order to identify the botanical origin of Aconiti Kusnezoffii Tuber circulated in Korea, we analyzed 24 samples of Aconiti Kusnezoffii Tuber obtained from local markets for comparative DNA analysis. The sequence analysis of nrRNA ITS 1 was useful to distinguish Aconitum species and revealed that the roots of A. karakolicum were circulated in Korean markets without discretion. HPLC quantitative analysis showed that aconitine was detected at the highest amount in A. karakolicum. Authentic diterpenoid alkaloids were coinjected for quantification of aconitine-type ingredients. All data were statistically grouped by Principal Component Analysis (PCA). This study suggests that both molecular and chemical analyses should be utilized for the standardization and the quality control for Aconiti Kusnezoffii Tuber.

• Bulletin of the Korean Chemical Society
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• v.34 no.8
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• pp.2394-2398
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• 2013

Nicotine is the main component of environmental tobacco smoke, and its presence in indoor air is widely used as a secondhand-smoke indicator. Environmental tobacco smoke is a major source of indoor air pollution, but sufficient investigation of the uncertainty of its measurement, which mirrors the reliability of nicotine measurement, has not been performed. We calculated the uncertainty of measurement of indoor air nicotine concentration at low, medium, and high concentrations of 11.3798, 10.1977, $98.3768{\mu}g/m^3$, respectively, and we employed the Guide to the Expression of Uncertainty in Measurements (GUM), proposed by the International Organization for Standardization (ISO). The factors considered in determining the uncertainty were uncertainty of the calibration curve (calibration curve and repeated measurements), desorption efficiency, extraction volume, and sampling airflow (accuracy and acceptable limits of flowmeter). The measurement uncertainty was highest at low concentrations; the expanded measurement uncertainty is $0.9435{\mu}g/m^3$ and is represented as a relative uncertainty of 63.38%. At medium and high (concentrations, the relative uncertainty was 13.1% and 9.1%, respectively. The uncertainty of the calibration curve was largest for low indoor nicotine concentrations. To increase reliability of measurement in assessing the effect of secondhand smoke, measures such as increasing the sample injection rate ($1{\mu}L$ or more), increasing sampling volume to increase collected nicotine, and using gas chromatography-mass spectrometry (GC/MS) or GC/MS/MS, which has a lower quantitation threshold, rather than gas chromatography with nitrogen phosphorous detector, should be considered.

• Journal of the Korean Chemical Society
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• v.42 no.4
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• pp.432-442
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• 1998

Since the definition of pH, $pH=-Ioga_H$ is based on a single ion activity, pH values can not be determined with measurement itself, but require an approximation method. They are derived from EMF measurement of a liquid junction free cell using hydrogen and Ag/AgCl electrodes. Primary standard materials with certified pH values can be obtained with this approximation method. Standard buffer solutions are used to calibrate pH meters. Thus the accuracy of the pH values of standard buffer solutions limits the reliability of measured pH values can be obtained with this approximation method. Standard buffer solution are used to calibrate pH meters. Thus the accuracy of the pH values of standard buffer solutions limits the reliability of measured pH values of sample solutions. To certify the pH values, we have established the system for the primary standard measurement and certified the pH of buffer solutions in the range of 1.6∼12.5 pH unit within uncertainty of ${\pm}0.005$ pH unit.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.41 no.3
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• pp.66-70
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• 2009

Paper cultural heritages usually experienced the chemical and the physical deterioration because of various factors including preservation environment and the property of their materials. General restoration technology for paper cultural heritages is the lining. The application of the lining paper and the lining technology has varied depending on researcher's experiences. Therefore, each lining material and technology must be evaluated to develop a standard guide for preservation and restoration of paper cultural heritages. To date, various analysis techniques using lining paper, in terms of their materials, have been applied to analyses of causes and condition of damages, but it is difficult to develop a standard restoration treatment method of paper cultural heritages because it varies by their material. The Hanf, is made frrr the mulberry, is generally used for the lining in Korea.edt is required that the cr, in terms properties and general properties of Hanf, is used for lining papers, are evaluated to develop a standard guide for their restoration.ed this study, the general properties of several lining papers(Hanf), especially dimensave bility, were evaluated as part of the standardization of lining papers. The result have varied depending on the pulping chemical and the manufacturers. the basis weight, thickness and tensale strength of lining papers is bigger the paper treated by natural ash than the paper treated by sodium carbonate.ed case of formation, folding endurance, and dimensave bility, the paper treated by sodium carbonate showed better properties than those of the paper treated by natural ash.

• Safety and Health at Work
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• v.15 no.1
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• pp.17-23
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• 2024

Background: The present study aimed to analyze several aspects of the working conditions and health status of platform workers in the Republic of Korea, such as ergonomic and emotional hazards. We also compared the health status of the platform workers with that of the general population. Methods: A total of 1,000 platform workers participated in this survey from August 7 to August 17, 2022. The participants included 400 designated drivers, 400 food-delivery drivers, and 200 housekeeping managers. A face-to-face survey with a structured questionnaire was conducted by researchers who had received specific instructions. The focus of the survey extended to the work environment, encompassing factors such as workplace violence, as well as physical, chemical, and ergonomic hazards. Health-related data for the previous year were also collected, covering a range of issues such as hearing problems, skin problems, musculoskeletal symptoms, headaches, injuries, mental health issues, and digestive problems. Subsequently, we compared the health symptom data of the responders with those of the general population in the Republic of Korea. Results: Platform workers, including designated drivers, food-delivery drivers, and housekeeping managers, existed in the blind spot of social insurance, facing frequent exposure to physical and chemical hazards, ergonomic risk factors, and direct or indirect violence. The prevalence of health problems, including musculoskeletal symptoms, general fatigue, and depressive symptoms, in each occupational group was statistically higher than that in the general population after standardization for age and gender. Conclusion: The results revealed unfavorable working environment and inferior occupational health of platform workers compared with those of the general population.

• Journal of the Korean Society of Safety
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• v.32 no.1
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• pp.108-114
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• 2017

According to an increase in demand for polyurethane soft foam for thermally insulated containers, the purpose of this study is based on redefining existing rigid polyurethane foam insulation KS standard which has been limited to building material-based authentication techniques. Since there are arising concerns of consumer rights and safety due to humidifier fungicides and urethane track incidents, there are elements to be further researched on rigid polyurethane foam insulation for refregerated containers. Thus, we reviewed the prior standards for rigid polyurethane foam insulation and verified the validity of certification testing method for the new standard with self-foamed polyurethane.

• The Korea Journal of Herbology
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• v.20 no.4
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• pp.133-140
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• 2005

Objectives : We have been used many herbal medicines after processing to improve the effect, decrease toxicity and side-effect, and change property. We have studied the physico-chemical change and HPLC pattern of Morindae Radix by means of processing method. Methods : This study was investigated the contents of loss on drying, residue on ignition, residue on acid insoluble ignition, 50% ethanol extract and HPLC pattern of Morindae Radix(Morinda officinalis How.) by processed and non-processed. We have conducted Morindae Radix and Damnacanthi Radix which is circulated in herbal medicine market by forgery. Processed Morindae Radix was prepared by heating of added to salt(SP), liquor(LP) and Glycyrrhizae Radix solution(GP) for 20-40 minutes. Results and Conclusions : From this analysis, we found that the content of 50% ethanol extract was increased by processing method. And we were detected distinguishable marker of processed and non-processed from Morindae Radix(Morinda officinalis How.) by HPLC pattern analysis.