• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.6
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• pp.529-537
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• 1993

Several methods were examined for purification of docosahexaenoic acid (DHA, 22:6n-3) from skipjack Euthynnus pelamis orbital tissue oil, a marine by-product, and a modified method for isolation of a high purity DHA was proposed. Skipjack orbital tissue contained $55.4\%$ of total lipid(TL), and DHA accounted for $23.7\%$ of the TL. Application of low-temperature crystallization and urea inclusion compound methods to the orbital fatty acid mixture resulted in increases of DHA concentrations to approximately $46\%\;and\;61\%$, respectively. These methods were suitable for large production of DHA with relative low purity because of the simple purification procedure. DHA of approximately $74\%$ in purity was obtained by silver nitrate aqueous solution method, but the method gave a very low recovery($<10\%$). Silver nitrate-impregnated silica column chromatography was suitable for purification of a high purity DHA(purity, $>98\%$ and recovery, $>90\%$) A modified method, silver nitrate-impregnated silica column chromatography combined with low-temperature crystallization(two step purication method) was proposed as the most effective method to obtain DHA with high purity($99.9\%$) from the skipjack orbital oil.

• Journal of Korea Soil Environment Society
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• v.2 no.1
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• pp.45-50
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• 1997

The change of industrial structure has brought the sharp declination of mine products, and has made many mines closed, which results in environmental pollution by untreated acid mine drainage(AMD). AMD with low pH and high concentration of heavy metals could severely destroy the ecosystem. Many researches have been carried out for the treatment of AMD. In this study, we have treated AMD with oak compost, mushroom compost, sludge cake and cow manure which usually used in AMD treatment systems, and compared the capability of each organic matter. Cow manure and oak compost have been most effective among 4 organic materials. Oak compost removed the heavy metals by ion exchange between Ca-rich particles and soluble heavy metal ions. It also captured the heavy metals using bound functional groups like -OH and -COO-. Sulfate reducing bacteria existing in the cow manure removed effectively heavy metals by producing metal sulfide compound. Therefore, it is effective to use both organic materials in mixture on the treatment of AMD.

• Journal of the Korean Chemical Society
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• v.9 no.1
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• pp.61-65
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• 1965

Metal distribution in the reaction products and system of reactions between organo chloro acid or ester and zinc, silicon, magnesium, and tin under acetonitrile, dioxane, and toluene solvent were determined by means of radioactive tracer prepared by means of a (n, ${\gamma}$) reaction. It was found that the solubility of the organo halogen metal complex was markedly increased in a hydrophilic solvent and was decreased in a nonpolar solvent which resulted in an increased metal distribution in the recovered metal or water washing of the recovered metal mixture. This was also true in the case of the reaction conducted in the presence of a carbonyl compound. The relative increase of the solubility of the metal complex in a hydrophilic solvent was in order of zinc, silicon, tin and magnesium, and in a nonpolar solvent, it was in order of silicon, tin, magnesium, and zinc. There was no formation of organo metallics throughout the reaction sequence. The result was discussed and the observed solvent influence on the present reaction path was criticized.

• International Journal of Highway Engineering
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• v.7 no.4 s.26
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• pp.9-20
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• 2005

This study was carried out to select most efficient bonding methods of geogrid at the interface of old concrete pavement before placing asphalt overlay layer for reflection cracking retardation. Three bonding methods, a RSC-4 emulsified asphalt, a compound and an unsaturated polyester resin (UPR) were compared in this study. Three types of asphalt mixture (AC 60-80, RLDPE 8%, PG 76-22) and a dense-graded aggregate were used for overlay asphalt pavement. A reinforcing material which consists of a woven fabric underneath a glass fiber grid was used. An expedite test method which is for simulating mixed mode (mode I and II) fracture test was performed using a wheel tracker in laboratory. Cracking development by load repetition was measured as fatigue life (number of load cycle) and expansion of specimen body were measured for each test specimen. The results showed that UPR was the best and RSC-4 the next. But considering field applicability, RSC-4 was considered as an appropriate choice for bonding reinforcing material.

• Bulletin of the Korean Chemical Society
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• v.32 no.7
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• pp.2260-2266
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• 2011

4-Chlorotetrazolo[1,5-a]quinoxaline (III) was synthesized by azide (2+3) cycloaddition of 2,3-dichloroquinoxaline (II). Compound (III) on further refluxing with hydrazine hydrate furnished 4-hydrazinotetrazolo[1,5-a]quinoxaline (IV). Further refluxing of (IV) with different aromatic aldehydes in methanol yielded corresponding Schiff's bases V(a-j). Various 4-aminotetrazolo[1,5-a]quinoxaline based azetidinones VII(a-j) were synthesized by stirring the compounds V(a-j), at low temperature, with equimolar mixture of chloroacetylchloride & triethylamine in dry benzene, while 4-aminotetrazolo[1,5-a]quinoxaline based thiazolidinones VIII(a-j) were synthesized by refluxing Schiff's bases V(a-j) with thioglycolic acid in oil-bath. The structures of all the compounds were confirmed on the basis of $^1H$-NMR & FT-IR spectral data. All the newly synthesized compounds were screened for in-vitro antimicrobial activity against E. coli, S. aureus, K. pneumoniae & P. aeruginosa & antifungal activity against C. albicans. Few of them have exhibited the promising activity.

• Applied Chemistry for Engineering
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• v.19 no.6
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• pp.661-667
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• 2008

In this study, cholesteric liquid crystal (CLC) was synthesized and applied as a polarizing component on the optical film of back light units (BLU) for LCDs. After mixing CLC with nematic liquid crystal, this mixture was fulfilled in the module consisting of two films and then its amplifying efficiency and polarizing ability for a planarly emitted light were examined to apply as a BLU polarizer film for increasing the brightness of light. The properties of CLC compound were tested by UV/Visible spectroscopy and polarizing optical microscopy (POM). Flexible spacer was made by linear carboxylic acid group of cholesteric derivatives between cholesterol mesogen units for one-axis orientation in each layer. The CLC containing film could be used as a module to increase the ability of polarization and to enhance brightness of BLU and to widen wavelength range by stacking the films.

• The Journal of Internal Korean Medicine
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• v.40 no.6
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• pp.1081-1100
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• 2019

Objectives: This study is an overview of the meta-analysis and systematic review of randomized controlled trials investigating the clinical effectiveness and safety of pharmacopuncture for patients with stroke. Methods: Core electronic databases were searched from their inception to 21 May 2019. A measurement tool to assess systematic reviews (AMSTAR 2) was applied to screen high-quality studies. The results of these studies were summarized, and additional meta-analysis was conducted. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) was used to evaluate the certainty of evidence. Results: Sixteen studies met eligibility criteria. Four were excluded owing to insufficiency of AMSTAR 2 or low data reliability. The finally selected 12 studies were about pharmacopuncture using either a single herb extract, such as Dengzhan xixin, Sanch, Ginkgo biloba, or Acanthopanax, or a mixture of herbs, such as Compound danshen, Shenxiong, Xingnaojing, or Mailuoning. Most of the patients were from China, with acute ischemic stroke. All the studies using a pharmacopuncture versus a non-pharmacopuncture design reported the significant superiority of pharmacopuncture on every outcome measure. On the other hand, in a few studies, pharmacopuncture was inferior to active control in improving neurological deficit. Few studies reported adverse events. Conclusions: It is difficult to apply the results of this study directly to Korea, because the level of evidence is generally low and the clinical settings and social acceptance of pharmacopuncture therapy differ in Korea and China. Further studies are warranted to confirm the domestic applicability of evidence generated in China and to create evidence that supports the domestic situation.

• Journal of Plant Biotechnology
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• v.34 no.2
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• pp.161-166
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• 2007

In vitro shoot regeneration and multiple shoot induction has been obtained from the stolen node explants in Eremochloa ophiuroides (Munro) Hack. The highest number of shoots ($10.66{\pm}0.21$) was observed from initial explants after one month culture duration on Murashige and Skoog (MS) medium containing 6-benzyladenine (BA: 0.5 mg/l). First generation shoot was excised and sub-cultured on the same fresh media for further multiplication of shoots. An enhanced number of second round shoots ($15.33{\pm}0.21$) was obtained compared to the initial culture media containing BA (0.5 mg/l). The number of shoots/stolon node was higher among all the concentrations of BA than kinetin (KN). In vitro regenerated shoots were successfully rooted in the phytohormone free MS medium. Plantlets generated with roots were transferred to pots containing compound mixture of soil and kept in green house conditions. Acclimatized plants showed 100% survival rate with normal morphology in green house conditions. The present study demonstrates the effect of explant and different plant growth regulators towards in vitro response in E. ophiuroides. Moreover, the study reveals the effect of cytokinin on induction of shoot number per stolen node explant in E. ophiuroides.

• Journal of Korean Society on Water Environment
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• v.32 no.6
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• pp.600-627
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• 2016

Korea is one of the countries with a large veterinary antibiotics market, although antimicrobial resistance in bacteria is becoming a serious issue in many countries. The Korean government started to take interest in estimating the effects of livestock manure on rivers and agricultural soils and in monitoring of heavy metals, organic pollutants and antibiotics in the ambient water and soil. In this paper, pre-treatment methods to separate the selected antibiotics from solid samples were reviewed. It is essential to select an efficient and appropriate procedure for pre-treatment due to the high proportion of proteins and organics in biosolid samples. Pre-treatment consists of extraction followed by clean-up. Initially, homogenized samples were extracted by sonication, mechanical agitation or pressurized liquid extraction with methanol/acetonitrile/water mixture under acidic/basic conditions depending on the compound. However, aminoglycosides and colistin were extracted with 5% trichloroacetic acid and HCl, respectively. Since the ${\beta}-lactams$ are easily decomposed in acidic and basic conditions, they were extracted in neutral pH. Filtration with a membrane (pore size, $0.2{\mu}m$) or solid phase extraction with HLB and methanol, as eluents, was normally applied for the clean-up. At least, three different pre-treatment procedures should be adopted to screen all the selected antibiotics in solid samples.

• Polymer(Korea)
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• v.24 no.6
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• pp.744-750
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• 2000

Oil gelling agent was synthesized with PPG, PTMG and TDI at 7$0^{\circ}C$ for 4hours. PPGs and PTMGs having various average molecular weights (M$_{n}$: 1000, 2000, 3000) were employed to investigate the ratio of oil gelation and water gelation. As M$_{n}$ of PPG, in result, was decreased from 3000 to 1000, the ratio of oil gelation was increased from 130% to 290% for PPG and from 250% to 310% for PTMG. Ratio of oil gelation was increased approximately two times when EG was added. As the amount of hydrophilic compound in the prepolymer was increased, ratio of oil gelation was increased from 290% to 1120% for PPG and increased from 310% to 1310% for PTMG, due to the increased dispersion of prepolymer in the water/oil mixture.ure.