• Electronics and Telecommunications Trends
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• v.34 no.4
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• pp.108-116
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• 2019

Electro-active polymers and dielectric elastomers have many intriguing properties that enable smart interfaces and electrically tunable optical systems, such as haptic feedback devices, artificial muscles, and expansion-tunable optical elements. These device classes are of great interest owing to their promising roles in next-generation technologies including virtual or augmented reality, human sensing and muscular enhancement, and artificial skins. In this report, we review basic principles, current state-of-the-art techniques, and future prospects of electro-active and dielectric elastomer technology. We describe chemical and physical properties of the most promising polymer substances, essential elementary architectures for artificial muscle-like functionalities, and their applications to haptic interfaces, muscular enhancement, and focus-tunable optical elements.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.4
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• pp.195-203
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• 2006

An antagonistic strain, Burkholderia MP-1, showed antimicrobial activity against various filamentous plant pathogenic fungi, yeasts and food borne bacteria (Gram-positive and Gram-negative). The nucleotide sequence of the 16S rRNA gene (1491 pb) of strain MP-1 exhibited close similarity (99-100%) with other Burkholderia 16S rRNA genes. Isolation of the antibiotic substances from culture broth was fractionated by ethyl acetate (EtOAc) solvent and EtOAc-soluble acidic fraction. The antibiotic substances were purified through a silica gel, Sephadex LH-20, ODS column chromatography, and high performance liquid chromatography, respectively. Four active substances were identified as phenylacetic acid, hydrocinnamic acid, 4-hydroxyphenylacetic acid and 4-hydroxyphenylacetate methyl ester by gas chromatographic-mass spectrum analysis. The minimum inhibition of concentration (MIC) of each active compound inhibited the growth of the microorganisms tested at 250 to $2500{\mu}g\;ml^{-1}$. The antimicrobial activity of crude acidic fraction at 1 mg of dry weight per 6 mm paper disc was more effective than authentic standard mixture (four active substances were mixed with the same ratio as acidic fraction) over a wide range of bacterial test.

• YAKHAK HOEJI
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• v.59 no.3
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• pp.98-106
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• 2015

Analytical method for related substances can be categorized into two methods depending on the necessity of reference standard (RS). The analytical method of related substances with RS is fast and accurate, but it's very expensive and technically difficult to synthesize RS due to their complicated structure. Another method is using relative retention time (RRT) and relative response factor (RRF) which are already validated with RS. Validation of this method is not easy and time consuming, but once it has been developed, it can save cost and time. In this study, we developed the analytical method for related substances of fenofibrate using RRT and RRF. We validated the method by evaluating specificity, linearity, accuracy and precision according to the "Manual for Guideline Application for Validation of Analytical Procedures" of MFDS. Also, we calculated RRT and RRF between fenofibrate and fenofibrate related substances. The results of this study showed high specificity for fenofibrate and fenofibrate related substances. Correlation coefficient(r) of all substances were more than 0.99, and the recovery of fenofibrate, fenofibrate related substance I, II and III were 99.44%, 100.84%, 99.14% and 101.58%, respectively. Precision of fenofibrate and its related substances were ranged between RSD 0.29% and 0.93%. Quantification limits of fenofibrate, fenofibrate related substance I, II and III were determined to be $0.03{\mu}g/ml$, $0.05{\mu}g/ml$, $0.04{\mu}g/ml$ and $0.02{\mu}g/ml$, respectively by confirming signal to noise ratio of each chromatogram. The RRT for fenofibrate related substance I, II and III were determined to be 0.35, 0.41 and 1.34, respectively. Also, the RRF for fenofibrate related substance I, II and III were determined to be 1.28, 0.98 and 0.79, respectively. The developed method was applied to determine contents for fenofibrate related substances in commercial fenofibrate (active pharmaceutical ingredient). As a result, developed analytical methods of related substances will be used for revising the monograph of fenofibrate in Korean Pharmacopoeia revision and contribute quality control of drugs by improving cost and time consuming problem of RS.

• Applied Biological Chemistry
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• v.41 no.2
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• pp.191-196
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• 1998

The MeOH extract from root of Pulsatilla koreana was showed antimicrobial activities against bacteria and yeast. The antimicrobial active substances of MeOH extract were successfully purified with solvent fractionation, silica gel adsorption column chromatography and Sephadex LH-20 column chromatography. The purified two active substances were isolated by HPLC and identified as 4-hydroxy-3-methoxycinnamic acid and 3,4-dihydroxycinnamic acid by MS, $^{1}H-NMR$ and $^{13}C-NMR$.

• Journal of Ginseng Research
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• v.21 no.1
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• pp.13-18
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• 1997

Identification and changes of physiologically active substances during chilling storage of dehisced ginseng (Panax ginseng C. A. Meyer) seeds were analyzed using various preparatory separation methods and purification columns; Dowex 50W and silica gel columns. Seven components with Rf values of 0.20, 0.40, 0.58, 0.66, and 0.70 In solvent system, $CHCl_3$:MeOH=3:1 (v/v), Rf values of 0. 63 and 0.74 in solvent system, $CHCl_3$:MeOH:$H_2O$:=7:3:1 (v/v) were obtained through Dowex 50W and silica gel column chromatographies. Two components with Rf values of 0.20 and 0.63 in the all chilling treatments were detected in the extract obtained through both chromatographies, and only the former component was gradually increased till 4 weeks of chilling storage and then rapidly decreased from 8 to 16 weeks. UV spectra of Rf values of 0.66 and 0.56 were similar to that of cytokinin, but their physiological activities were not found. Rf values of 0.20 showed activity by radish cotyledon expansion bioassay. The component with Rf value of 0.20 was revealed to have a naphthalene in the proposed chemical structure by various NMR techniques.

• Applied Biological Chemistry
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• v.36 no.5
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• pp.376-380
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• 1993

To investigate the presence of the brassinosteroid substances in immature Oryza sativa L. cv Tongjinbyeo seeds, the methanol extract was purified by the sequential use of solvent fractionation, silica gel adsorption chromatography, Sephadex LH-20 chromatography and charcoal adsorption chromatography. The activity of brassinosteroid was monitored by the rice inclination test and its presence could be confirmed in each purification step. The purified active components were separated by silica gel adsorption chromatography and Sephadex LH-20 chromatography. Brassinosteroid substances in separated active fractions were identified as castasterone, teasterone and 6-deoxocastasterone by HPLC. Our work is probably the first report of endogenous brassinosteroids in Oryza sativa seeds. The content of brassinosteroid in Oryza sativa seeds as converted into brassinolide was $0.5{\sim}1.5\;ng/g$ fresh weight.

• Journal of Korean Society of Water and Wastewater
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• v.37 no.5
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• pp.253-259
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• 2023

Bioreactors are devices used by sewage treatment plants to process sewage and which produce active sludge, and sediments separated by solid-liquid are treated in anaerobic digestion tanks. In anaerobic digestion tanks, the volume of active sludge deposits is reduced and biogas is produced. After dehydrating the digestive sludge generated after anaerobic digestion, anaerobic digested wastewater, which features a high concentration of organic matters, is generated. In this study, the decomposition of organic carbon and nitrogen was studied by advanced oxidation process. Ozone-microbubble flotation process was used for oxidation pretreatment. During ozonation, the TOC decreased by 11.6%. After ozone treatment, the TOC decreased and the removal rate reached 80.4% as a result of the Ultra Violet-Advanced Oxidation Process (UV-AOP). The results with regard to organic substances before and after treatment differed depending on the organic carbon index, such as CODMn, CODCr, and TOC. Those indexes did not change significantly in ozone treatment, but decreased significantly after the UV-AOP process as the linkage treatment, and were removed by up to 39.1%, 15.2%, and 80.4%, respectively. It was confirmed that biodegradability was improved according to the ratio of CODMn to TOC. As for the nitrogen component, the ammonia nitrogen component showed a level of 3.2×10² mg/L or more, and the content was maintained at 80% even after treatment. Since most of the contaminants are removed from the treated water and its transparency is high, this water can be utilized as a resource that contains high concentrations of nitrogen.

• Journal of the Korean Applied Science and Technology
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• v.38 no.1
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• pp.292-299
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• 2021

In this study, a study was attempted to confirm the yield of the solvent fraction for extracting physiologically active substances of polyphenols and flavonoids in sea cucumber. In the previously reported cases, the 50% ethanol extraction solvent fraction was confirmed as a result of high yield of sea cucumber antioxidants. The determination of the amount of antioxidants extracted from sea cucumber was confirmed as a result of the extraction solvent fraction applied to the extraction. In addition, the necessity of extraction of the solvent fraction was obtained through a previous study that 'there is a significant difference in the content of sea cucumber physiologically active antioxidants extracted depending on the extraction solvent.' The results of extracting high antioxidants from the phenolic substances contained in the sea cucumber extract of the 50% ethanol extraction solvent fraction were demonstrated. In the study case of extraction solvent fraction, the ethyl acetate solvent fraction, which yielded the lowest, yielded a higher phenol content than other solvent fractions, and the antioxidant effect was confirmed. Accordingly, it was confirmed that the effect on the high yield of the antioxidant extract through the yield change according to the application of the extraction solvent fraction was performed. Therefore, it was verified as an optimized sea cucumber physiologically active substance extraction solvent fraction of 50% ethanol solvent.

• Journal of the Korean Applied Science and Technology
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• v.39 no.1
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• pp.108-114
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• 2022

In this study, the antioxidant effect of black sea ginseng containing a large amount of eicosapentaenoic acid, a natural physiologically active substance, was investigated, and its superiority as a functional cosmetic raw material was presented. The ability of the sea cucumber extract to remove active oxygen was evaluated for the inhibitory effect on intracellular nitric oxide (NO) production. The physiologically active substances of sea cucumber have an antioxidant effect that removes free radicals, and as a result of evaluation, it was confirmed that excellent NO production was suppressed. Studies have shown that bioactive substances are involved in antioxidant effects, immune and inflammatory response regulation by showing high antioxidant efficacy even at low concentrations. It is thought that the antioxidant removal ability of sea cucumber greatly contributes to the antioxidant efficacy of phenolic components containing EPA (eicosapentaenoic acid) of the sea cucumber extract. It was found to be similar to the report that the antioxidant component of sea cucumber works. In addition, it is excellent for wound healing with the eicosapentaenoic acid (EPA) component contained in a large amount of sea cucumber extract, which has been proven to be involved in the inhibitory effect of inflammatory activity. As a result of this study, it was confirmed that the effect of the phenol component contained in the sea cucumber extract had a close causal relationship with the antioxidant activity.

• Natural Product Sciences
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• v.17 no.4
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• pp.342-349
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• 2011

This study was performed to determine the composition of phenolic substances contained in the leaves of Cirsium setidens (Compositae), validate the high-performance liquid chromatography (HPLC) method, and determine the in vivo sedative effect of the main component pectolinarin. Six phenolic compounds isolated from C. setidens were spectroscopically identified as chlorogenic acid (1), hyperoside (2), 3,4-di-O-caffeoylquinic acid (3), caffeic acid methyl ester (4), linarin (5), and pectolinarin (6) and then used as standard compounds for HPLC analysis. HPLC proved to be precise, accurate, and sensitive for the simultaneous analysis of the phenolic substances. In particular, six compounds showed good regression ($R^2$ > 0.999) within test ranges and recovery was in the range of 95.4 - 104.8%. The content of pectolinarin was considerably higher (156.48 mg/g) than those of other phenolic substances including the other flavone glycoside, linarin (18.99 mg/g). The contents of other phenolic substances, in order, were chlorogenic acid (8.41 mg/g), 3,4-di-O-caffeoylquinic acid (5.74 mg/g), hyperoside (4.33 mg/g), and caffeic acid methyl ester (0.51 mg/g). Oral administration with compound 6 (10 and 20 mg/kg) enhanced the sleeping time induced by pentobarbital in mice, indicating that it has a sedative effect.