• Bulletin of the Korean Chemical Society
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• 제32권5호
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• pp.1564-1568
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• 2011

A solvent extraction separation, preconcentration and determination of thorium with a new crown, 2-ethyl-N-benzyl-4,7,10,13,16-pentaoxa-1-azacyclooctadecane (MACE), is described in the study. The amount of thorium in the aqueous phase and organic phase was determined by Inductively Coupled Plasma-Optical Emission Spectroscopy and Ultraviolet-Visible, respectively. Thorium loaded organic phase was quantitatively stripped in a stage by using 1.0 M $HNO_3$. Thorium was effectively extracted with MACE in the pH range of 6-7 to produce a 3:2 complex ratio in the chloroform. A highly sensitive and rapid spectrophotometric method was described for determination of trace amounts of thorium with MACE. The effective molar absorption coefficient at 281 nm is $1.98{\times}10^3\;mol^{-1}cm^{-1}$, and the system complies with Beer's law in the range from 0.464 to 2.32 ${\mu}gm\;L^{-1}$ of thorium. Thorium was also determined in standard and environmental samples.

• 에너지공학
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• 제29권3호
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• pp.34-41
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• 2020

Used disposable diapers have been considered for a long time as a type of waste difficult to recycle and valorize due to their composite nature including plastic, cellulose pulp, a super absorbent polymer and either urine, feces or both. Therefore, the fate of disposed diapers often is either incineration or landfill burial which both have various adverse environmental impacts. However, used disposable diapers contain nutrients: cellulose is an organic matter while urine and feces contain non negligible amounts of nitrogen, phosphorus and potassium which are primary nutrients included in most chemical fertilizers used in agriculture. In a scope of waste recycling and valorization, this study focuses on developing a method to achieve nutrient solution extraction from used disposable diapers. The experiment essentially consists in shredding the diapers and letting them macerate in solutions of sodium hydroxide with various concentrations to allow breaking down of the cellulose and super absorbent polymer and release of urine and feces before sterilizing the solutions in an autoclave to remove potential coliform bacteria. At the end of the experiment, a set of parameters is measured for the final solution to identify concentrations of nutrients as well as presence or absence of harmful substances. Results are discussed and directions for future studies are suggested, which include mechanization of the diapers shredding process or added aeration to enhance nitrification and absorption of extracted nutrients from plants.

• 분석과학
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• 제6권3호
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• pp.283-288
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• 1993

기체 크로마토그래피를 이용하여 과수 재배용 살균제인 nuarimol의 분석을 위한 최적 조건을 조사하고 사과 중에서의 잔류성을 규명하였다. 사과시료를 methanol로 추출, 여과한 후 4.00% NaCl과 dicholromethane액으로 분리농축하고, alumina 컬럼상에서 1-chlorobutane과 methanol 혼합액으로 정제하여 GLC/ECD로 분석하였다. 0.200와 1.00ppm 표준물 첨가 실험결과 평균 회수율이 79~95%였고, 사과 중 nuarimol의 잔류량은 수확 3일 전 8회 처리시 0.0830ppm이었다. 사과에 대한 안전 사용기간은 수확 7일전 6회 사용이 적당한 것으로 나타났다.

• 한국식품영양학회지
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• 제28권1호
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• pp.143-152
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• 2015

Vitamin D contents in agricultural products and foods were quantified by high performance liquid chromomatography (HPLC) with a UV/Vis detector, using external standard methods. The results were confirmed with liquid chromatography tandem mass spectrometry (LC-MS/MS). After homogenization, samples were hydrolyzed by direct alkali saponification. Thereafter, fat-soluble components were extracted with n-hexane containing 0.01% butylated hydroxytoluene (BHT). Vitamin D contents in cereals were found to be in the range of $1.882{\sim}4.856{\mu}g/100g$. Juda's ear and oak mushroom contained high amounts of vitamin D, at 363.85 and $199.42{\mu}g/100g$ of edible portion, respectively.

• Food Science and Biotechnology
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• 제16권3호
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• pp.493-495
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• 2007

In this study, the acrylamide contents of foods were estimated via liquid chromatography (LC)/mass spectrometry (MS)/MS after the food matrix constituents had been degraded with digestive enzymes (i.e., pepsin and pancreatin) and extracted with water. The quantities of acrylamide released from samples of cereal, potato chips, peanuts, and coffee were $62{\pm}5.1,\;970,\;106{\pm}20$, and 890 ppb, respectively. No acrylamide was detected in samples of soybean curd (tofu), fish cake, and ham. Compared to the amounts of acrylamide detected after extraction with water only, we noted no significant differences in the soybean curd, fish cake, potato chip, ham, and coffee samples. However, the quantities of acrylamide released from the cereal and peanut samples were approximately 2-fold larger following pretreatment with the digestive enzymes. This study presents a new in vitro enzymatic digestion method which allows for a more accurate estimation of the acrylamide contents of foods.

• 한국식품영양학회지
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• 제23권4호
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• pp.446-452
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• 2010

In this study, Boehmeria nivea were extracted with water and ethanol, and antioxidative activity was investigated along with the quality of cookies prepared with added Boehmeria nivea, as a functional food. Among the water and ethanol extracts, high electron donating abilities were found. we selected various quantities of Boehmeria nivea(0%, 3%, 6%, 9%, 12%, 15%) to add to the cookies as an independent variable and performed sensory tests, as well as, measured chromaticity, and property of matter measurements. The rates of brightness, redness, and yellowness(p<0.001) changed significantly with increasing quantities Boehmeria nivea. The rates for spread ratio, hardness, brittleness, and chewiness(p<0.001) also changed siginificantly with increasing amounts Boehmeria nivea. Finally, texture(p<0.05), appearness, sweetness(p<0.01), bitterness, and overall quality(p<0.001) were examined in sensory tests and showed significant differences. Based on the above results, the cookies that contained 3~9% of Boehmeria nivea presented the best quality.

• 대한공간정보학회지
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• 제12권4호
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• pp.75-81
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• 2004

임하호 유역은 지질 및 토지피복 상태가 토사유실에 취약한 특성을 가지고 있어, 강우발생시 토사가 하천에 유입되어 호소내에 많은 탁수가 발생하고 있다. 본 연구에서는 임하호 탁수 저감대책을 수립하기 위한 기초자료를 생성하기 위해 GIS 기반RUSLE 모형을 이용하여 임하호 유역의 토사유실량을 분석하였다. 2003년도 강우자료를 이용하여 토사유실량을 분석한 결과 5,782,829 ton/yr로 계산되었으며, 소유역별 분석에서는 동부천이 가장 높은 토사유실량을 나타내었다. 또한 태풍매미때의 탁수실측자료를 이용하여 RUSLE 모델로 산정한 토사유실량의 적정성을 평가할 수 있었다.

• The Korean Journal of Physiology and Pharmacology
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• 제2권5호
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• pp.591-600
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• 1998

We have examined 24 human aortas aged $46{\sim}90$ years obtained from autopsies. Most exhibited gross lesions of some degree on the lumenal surface. Using hot alkaline treatment (0.1 N NaOH) at $70{\sim}75^{\circ}C$ for 5 hours, we extracted and quantitated elastin portions from the aortic wall in 3 different segments (UTA=upper thoracic aorta, LTA=lower thoracic aorta, AA=abdominal aorta). We have found UTA had $70.6%{\pm}1.39$ (SE), LTA $61.6%{\pm}1.94$ (SE), AA $49.2%{\pm}1.84$ (SE) elastin respectively based on wet weight. The differences between segments are statistically significant (p＜0.05, 0.025). However, there is no significant correlation between the age of the patients and the relative amounts of elastin in each segment. We have also observed the structure of elastin in the internal elastic lamina (IEL) and tunica media (TM) with SEM (scanning electron microscopy), and discovered that the IEL shows various forms of elastolysis- broken sheets, discontinuity, various sizes of lumps, vesicles, and possible newly formed elastin in the aortic lesions (Song and Roach submitted to YMJ). From these studies we conclude that elastin in the aortic wall remains well balanced quantitatively with age in spite of evidence suggesting vigorous degeneration and regeneration in the atherosclerotic lesions.

• 한국식품저장유통학회지
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• 제5권1호
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• pp.49-56
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• 1998

The effects of the water extracts from thyme(TM) and tarragon(TG) on shelf-life and quality of kimchi were investigated by measuring the changes in pH, acidity, number of total microorganisms, number of Lactobacillii and Leuconostoc during fermentation at 1$0^{\circ}C$, and were tested for antimicrobial activities against Lactobacillus plantarum and Leuconostoc mesenteroides. TM and TG were extracted with water, ethyl ether, ethyl acetate and ethanol. Water, ethyl ether, ethyl acetate and ethanol extracts of TM showed antimicrobial activities against Lactobacillus plantarum and did not observed against Leuconostoc mesenteroides. On the other hand, water, ethyl acetate and ethanol extracts of TG showed antimicrobial activities against Leuconostoc mesenteroides and did not observed against Lactobacillus plantarum. The decrease of pH and the increase of acidity showed lower in kimchi prepared by adding water extracts from TM than in products from TG. The number of total microorganisms were also detected less in the kimchi prepared by adding water extracts from TM. And, the properties of barkless of kimchi measured instrumentally were higher for kimchi prepared by adding water extracts from TM, also maintaining good crispness. The optimal addition amounts of both TM and TG for good overall and spicy taste of kimchi were 0.03%. The results suggested the possible use of the extracts of TM and TG can be successfully used for the quality and extension of shelf-life of kimchi.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2018년도 추계학술대회
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• pp.99-99
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• 2018

The major aim of this work is the research of secondary metabolites isolated from the aerial parts of Petasites japonicus. The plant material is extracted with a polar solvent, which is 95% by volume methanol at room temperature. The concentrated extract was partitioned as EtOAc, n-BuOH, and $H_2O$ fractions. From the EtOAC and n-BuOH fraction, two bakkenolides and two caffoylquinic acid were isolated using the Diaion HP-20, silica gel, ODS-A, and Sephadex LH-20 column chromatographies. According to the results of the results of physico-chemical and spectroscopic data including NMR, MS and UV. The chemical structures of the compounds were respectively determined as bakkenolide B (1), bakkenolide D (2), 1,5-dicaffeoylquinic acid (3), and 5-O-caffeoylquinic acid (4). These results suggest that the compounds isolated from the aerial parts of this plant were almost identical with known components of Petasites japonicus. However, it is necessary to investigate more about the difference of amounts of constituents according to harvest area and time.