• Analytical Science and Technology
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• v.16 no.2
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• pp.166-173
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• 2003

To determine levels of PCBs in food, beef, pork, chicken, egg, mackerel, yellow croaker, anchovy, common squid and little neck clam were chosen and collected at markets in Seoul, Busan and Kwangju. Among 209 PCB congeners, 7 congeners (#28, #52, #101, #118, #138, #153 and #180) were selected as target compounds that were known as indicator congeners. Samples were homogenized, treated in alkali solution for 1 hour, and extracted with organic solvents. After extraction, extracts were cleaned up by sulfuric acid, purified on silica gel column chromatography, analyzed by dual column-HRGC/ECD and then confirmed by HRGC/MSD. As results, PCBs were detected in fish samples ranged from 0.0002 to 0.001 mg/kg. Both PCB #101 and PCB #118 were the major contributors among 7 congeners.

• Korean Journal of Food Science and Technology
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• v.23 no.1
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• pp.68-75
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• 1991

The seed oil of Ternstroemia gymnanthera. a species of the Ternstroemiaceae, is mainly composed of triglyceride(92.4%), followed by polar lipids(5.9%), sterol(1.2%) and pigments(0.5%). This oil contains 4.8% of cis-11, 12-methylene octadecanoic acid(lactobacillic acid) in the fatty acid composition of the total oil. This identification is based on information from non-urea inclusion formation, silver nitrate impregnated silica gel column and gas liquid chromatography, $^1H-&\;^{13}C-nuclear$ magnetic resonance and mass spectroscopy. Smaller amounts(0.1%) of presumptive 9, 10-methylene hexadecanoic acid(dihydro malvalic acid) is also detected. The major fatty acids in this oil are C18 : 1(36.1%), C18: 2(30.9%), C16: 0(15.1%), C16: 1(7.6%) and C18: 0(3.4%).

• Journal of Microbiology and Biotechnology
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• v.11 no.6
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• pp.1018-1023
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• 2001

Oleamide (cis-9-octadecenamide) is endogenous primary amide of fatty acid that is produced in small amounts in animal brains. It is known to induce sleep and to lower temperature by destroying the lipid plasma membrane structure of cells, thereby disclosing gap junction channels. To develop a new biological production method for oleamide, a screening program was conducted to isolate a microorganism producing oleamide. Among 1,500 soil microorganisms tested, KK90378 exhibited a potent positive reaction with Dragendoff`s reagent, used to detect the primary amide of oleamide. KK90378 was identified as a Streptomyces species based on cultural and morpohological characteristics, the presence of diaminopimelic acid in the cell wall, and the sugar patterns for the whole-cell extrat. Streptomyces sp. KK90378 produced oleamide 3 days after culture at $28^{\circ}C$, pH 7.2 A series of purification steps, including hexane extraction, silica gel column, and preparative thin layer chromatographies, were performed for the purification of oleamide. A spectrophotometric analysis using $^1H$, $^13C$-NMR, and GC-MS confirmed that the chemical structure of the purified oleamide was identical to that of authentic oleamide.

• Journal of Microbiology and Biotechnology
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• v.15 no.5
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• pp.1001-1010
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• 2005

Bacillus megaterium KL39, an antibiotic-producing plant growth promoting rhizobacterium (PGPR), was selected from soil. The antifungal antibiotic, denoted KL39, was purified from culture filtrate by column chromatography using Dion HP-20, Silica gel, Sephadex LH-20, and prep-HPLC. Thin layer chromatography, employing the solvent system of ethanol:ammonia:water=8:1:1, showed the $R_{f}$. value of 0.32. The antibiotic KL39 showed a negative reaction with ninhydrin solution, positive with iodine vapor, and also positive with Ehrlich reagent. It was soluble in methanol, ethanol, butanol, and acetonitrile, but insoluble in chloroform, toluene, hexane, ethyl ether, or acetone. Its UV spectrum had the maximum absorption at 208 nm. Amino acid composition, FAB-mass, $^{1}H-NMR,\;^{13}C-NMR$, and atomic analyses showed that the antibiotic KL39 (MW=1,071) has a structure very similar to iturin E. The antibiotic KL39 has a broad antifungal spectrum against a variety of plant pathogenic fungi including Rhizoctonia solani, Pyricularia oryzae, Monilinia froeticola, Botrytis cinenea, Altenaria kikuchiana, Fusarium oxysporum, and F. solani. An MIC value of $10\;{\mu}g/ml$ was determined for Phytophthora capsici. Macromolecular incorporation studies with P. capsici using radioactive [$^{3}H-adenine$] as the precursor, indicated that the antibiotic KL39 strongly inhibits the DNA biosynthesis of the fungal cell. Microscopic observation of the antifungal action showed abnormal hyphal swelling of P. capsici. The purified antibiotic KL39 was very effective for the biocontrol of in vivo Phytophthora-blight disease of pepper.

• Membrane and Water Treatment
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• v.6 no.2
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• pp.127-139
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• 2015

Rejection of ionic solutes by reverse osmosis (RO) and nanofiltration (NF) membranes is controlled mainly by electrochemical interaction as well as pore size, but it is very difficult to directly evaluate such electrochemical interaction. In this work, we used an inverse HPLC method to investigate the interaction between ionic solutes and poly (m- phenylenediaminetrimesoyl) (PPT), a polymer similar to the skin layer of polyamide RO and NF membranes. Silica gel particles coated with PPT were used as the stationary phase, and aqueous solutions of the ionic solutes were used as the mobile phase. Chromatographs obtained for the ionic solutes showed features typical of exclusion chromatographs: the ionic solutes were eluted faster than water (mobile phase), and the exclusion intensity of the ionic solute decreased with increasing solute concentration, asymptotically approaching a minimum value. The charge density of PPT was estimated to be ca. 0.007 mol/L. On the basis of minimum exclusion intensity, the exclusion distances between a salt and neutralized PPT was examined, and the following average values were obtained: 0.49 nm for 1:1 salts, 0.57 nm for 2:1 salts, 0.60 nm for 1:2 salts, and 0.66 nm for 2:2 salts. However, $NaAsO_2$ and $H_3BO_3$, which are dissolved at neutral pH in their undissociated forms, were not excluded.

• Journal of Applied Biological Chemistry
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• v.52 no.4
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• pp.221-225
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• 2009

Lithospermum erythrorhizon has been known well as one of traditional medicine for fever reduction, detoxication, and blood circulation improvement. This study was carried out to isolate biological active compounds from roots of Lithospermum erythrorhizon and to investigate their low density lipoprotein (LDL) antioxidant and anticancer activities. The hexane extract of Lithospermi Radix has been separated on silica gel chromatography and a naphthoquinone pigment compound 1 has been isolated. The structure of the compound 1 has been identified by spectroscopic technique, including MS and NMR, as acetylshikonin (1). Acetylshikonin showed significantly inhibitory activity on $Cu^{2+}$-induced human LDL oxidation with $IC_{50}$ value of $8.8\;{\mu}M$ and obvious anticancer effect by inhibiting farnesyl:protein transferase (FPTase) activity with $IC_{50}$ value of $23\;{\mu}M$, which suggested that acetylshikonin might be useful for the treatment of atherosclerosis and cancer.

• Journal of Biosystems Engineering
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• v.2 no.2
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• pp.1-14
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• 1977

현재 선진국에서 널리 이용되고있는 곡물의 화력건조는 곡물의 품질을 손상시킬 뿐만 아니라 손실을 증가시키고 있다. 화력에 의한 건조는 또한 연료의 절약면에서 볼 때 역시 문제점을 내포하고있다.l 이러한 문제점들을 해결하기 위하여 근래에는 실리카 젤과 같은 흡습성의 건조제를 사용한 곡물의 건조 실험이 진행 중에 있으며 좋은 결과를 보여주고 있다. 실리카겔은 그 자체무게의 40% 까지 동적 및 정적하에서 수분을 흡수하는 성질을 가지고 있으며 일단 포화상태가 되면 수천번 재생이 가능하다. 본 연구에서는 이와같은 실리카텍의 재생실험을 일차적으로 실내에서 공기의 온도를 일정하게 한 상태에서 실시하였으며 일반적으로 실리카 젤은 $300^{\circ}F$에서 완전재생이 가능하나 본 실험에서 사용된 재생온도는 평면식 태양열 집열기로부터 얻을 수 있는 $150^{\circ}F$ 내외에서 시도하였다. 본실험과 병행하여 건조중 공기와 실리카 젤의 에너지 및 질량변화에 따른 이론식을 만들어 주어진 여러 가지 조건에 대하여 4개의 미분방정식을 컴퓨터에 의하여 해결하였으며 건조(재생) 시간에 따른 공기의 온도와 흡습 및 실리카 젤의 함수량을 구하였다. 위의 이론적인 분석결과는 후에 태양열집열기를 이용한 재생실험을 분석하는데 적용될 것이다. 본 연구결과를 요약하면 다음과 같다. 1. 본 연구에서 유도한 이론식은 실리카 젤의 재생온도를 만족스럽게 표시하였으며 재생시간에 따른 공기의 온도와 흡습 및 실리카 젤의 함수량변화의 이론치는 실험치와 근사하였다. 2. 이론치와 실험치를 일치시키기위하여 흡착온도에서 산출된 열 및 질량 전달계수를 1/5로 조정 사용하였다. 3. 실리카 젤은 $120^{\circ}F$에서 9 %, $180^{\circ}F$에서 1% 내외로 재생이 가능하였다. 4. 본 연구에서 유도된 이론적 분석방법은 다른 여러 가지 형태의 물질 및 건조 또는 냉각 과정을 분석하는데 사용될 수 있다.

• Journal of Powder Materials
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• v.21 no.5
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• pp.377-381
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• 2014

This work describes the coloration, chemical stability of $SiO_2$ and $SnO_2$-coated blue $CoAl_2O_4$ pigment. The $CoAl_2O_4$, raw materials, were synthesized by a co-precipitation method and coated with silica ($SiO_2$) and tin oxide ($SnO_2$) using sol-gel method, respectively. To study phase and coloration of $CoAl_2O_4$, we prepared nano sized $CoAl_2O_4$ pigments which were coated $SiO_2$ and $SnO_2$ using tetraethylorthosilicate, $Na_2SiO_3$ and $Na_2SiO_3$ as a coating material. To determine the stability of the coated samples and their colloidal solutions under acidic and basic conditions, colloidal nanoparticle solutions with various pH values were prepared and monitored over time. Blue $CoAl_2O_4$ solutions were tuned yellow color under all acidic/basic conditions. On the other hand, the chemical stability of $SiO_2$ and $SnO_2$-coated $CoAl_2O_4$ solution were improved when all samples pH values, respectively. Phase stability under acidic/basic condition of the core-shell type $CoAl_2O_4$ powders were characterized by transmission electron microscope, X-ray diffraction, CIE $L^*a^*b^*$ color parameter measurements.

• Applied Biological Chemistry
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• v.38 no.4
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• pp.293-296
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• 1995

Fig leaves were extracted with methanol and then fractionated with ethyl acetate and various buffers to get active fractions and determined the antimicrobial activities. The acidic and phenolic fractions fractionated from the methanol extract of fig leaves showed the strong antimicrobial activities, but the basic and neutral fractions did not show any activities. The degree of antimicrobial activities of phenolic fraction against tested bacteria was higher than those of acidic fraction, but these against yeasts and mold were almost equivalent to those of acidic fraction. Especially, phenolic fraction was mostly affected on Staphylococcus aureus and Pseudomonas aeruginosa. Four antimicrobial substances purified from the phenolic fraction which showed the strongest antimicrobial activities among the fractions from fig leaves, were identified as psoralen($C_{11}H_{6}O_{3}$, MW. 186), bergapten($C_{12}H_{8}O_{4}$, MW. 216), ${\beta}$-sitosterol($C_{29}H_{50}O$, MW. 414) and umbelliferone ($C_{9}H_{6}O_{3}$, MW. 162).

• Journal of Microbiology and Biotechnology
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• v.16 no.5
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• pp.716-723
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• 2006

A biosurfactant-producing bacterial strain was selected from oil-contaminated soil because of its ability to degrade crude oil and tributyrin $(C_{4:0})$. The strain was identified as Bacillus subtilis A8-8 based on its morphological, biochemical, and physiological characteristics. When B. subtilis A8-8 was grown with crude oil as the sole carbon source, the biosurfactant from the strain emulsified crude oil, vegetable oil, and hydrocarbons. Soybean oil was the optimum substrate for the emulsifying activity and emulsion stability of the biosurfactant, both of which were superior to those of several commercially available surfactants. The biosurfactant was purified by a procedure including HCl precipitation, methanol treatment, and silica-gel chromatography. The partially purified biosurfactant was analyzed by TLC (thin-layer chromatography), SDS-PAGE, and HPLC and it reduced the surface tension of water from 72 mN/m to 26 mN/m at a concentration of 30 mg/l. Therefore, the purified lipopeptide biosurfactant has strong properties as an emulsifying agent and acts as an emulsion-stabilizing agent.