• Journal of the Korean Crystal Growth and Crystal Technology
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• v.17 no.1
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• pp.23-29
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• 2007

Pitch-coated anatase $TiO_2$ typed was prepared by $CCl_4$ solvent mixing method with different mixing ratios. Since the carbon layers derived from pitch on the $TiO_2$ particles were porous, the pitch-coated $TiO_2$ sample series showed a good adsorptivity and photo decomposition activity. The BET surface area for the carbon layer in the sample increases to increasing with pitch contents. The SEM results present to the characterization of porous texture on the pitch-coated $TiO_2$ sample and pitch distributions on the surfaces for all the materials used. From XRD data a weak and broad carbon peak of graphene with pristine anatase peaks were observed in the X-ray diffraction patterns for the pitch-coated $TiO_2$. The EDX spectra show the presence of C, O and S with strong Ti peaks. Most of these samples are richer in carbon and major Ti metal than any other elements. Finally, the excellent photocatalytic activity of pitch-coated $TiO_2$ with slope relationship between relative concentration of MB ($c/c_o$) and t could be attributed to the homogeneous coated pitch on the external surface by $CCl_4$ solvent method.

• Journal of Gifted/Talented Education
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• v.13 no.2
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• pp.43-56
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• 2003

In this study, learning materials that can be applied for web-based distant learning model were developed based on the characteristics of elementary school science in which investigation skills and thinking ability are considered to be important. And the effect of students' activity in a discussion room on student's investigating and thinking ability was investigated. Through very active on-line discussion, students showed their ability to come up with new ideas and to design and implement diverse experimental methods. Especially, since all of the study tasks given to the students were aimed to utilize experimental means and tools that are so common in everyday life, shortfalls that might reside in the web-based distant learning program could be overcome and students' investigative activity might be stimulated.

• Carbon letters
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• v.8 no.1
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• pp.6-11
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• 2007

Carbon/$TiO_2$ composites were prepared by $CCl_4$ solvent mixing method with different mixing ratios. Since the carbon layers derived from pitch on the $TiO_2$ particles were porous, the Carbon/$TiO_2$ composite series showed a good adsorptivity and photo decomposition activity. The BET surface area for the carbon layer in the sample increases to increasing with pitch contents. The SEM results present to the characterization of porous texture on the Carbon/$TiO_2$ composite and pitch distributions on the surfaces for all the materials used. From XRD data, a weak and broad carbon peak of graphene with pristine anatase peaks were observed in the X-ray diffraction patterns for the Carbon/$TiO_2$. The EDX spectra show the presence of C, O and S with strong Ti peaks. Most of these samples are richer in carbon and major Ti metal than any other elements. Finally, the excellent photocatalytic activity of Carbon/$TiO_2$ with slope relationship between relative concentration (C/$C_0$) of MB and t could be attributed to the homogeneous coated pitch on the external surface by $CCl_4$ solvent method.

• Archives of Pharmacal Research
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• v.28 no.10
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• pp.1122-1126
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• 2005

Tungtungmadic acid (3-caffeoyl-4-dihydrocaffeoyl quinic acid) is a new chlorogenic acid derivative that was isolated from the Salicomia herbacea. The structure of tungtungmadic acid was determined using chemical and spectral analysis. The antioxidant activity of tungtungmadic acid was evaluated using various antioxidant assays, including free radical scavenging, lipid peroxidation and hydroxyl radical-induced DNA strand breaks assays. Tungtungmadic acid ($IC_{50}\;=\;5.1\;{\mu}M\;and\;9.3\;{\mu}M$) was found to have higher antioxidant activity in the DPPH scavenging assay as well as in the iron-induced liver microsomal lipid peroxidation system. In addition, the tungtungmadic acid was also effective in protecting the plasmid DNA against strand breakage induced by hydroxyl radicals.

• Journal of the Korean Society of Food Culture
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• v.30 no.6
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• pp.778-782
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• 2015

Demand for organic agriculture has greatly increased in the past decade. The objective of this study was to evaluate quality the characteristics and antioxidant activities of organically and conventionally grown carrots. Organically and conventionally grown carrots were harvested in Jeju Island, Korea. Carrot extracts were investigated for their antioxidative components (total phenolic and flavonoid contents) and their antioxidant activities (DPPH and ABTS radical scavenging activities). The quality characteristics of carrots were estimated in terms of hardness, length, weight, moisture contents, and soluble solid content (SSC). Conventionally grown carrots showed higher values than organic carrot in terms of hardness (p<0.05), but there was no significant difference in moisture contents or SSC. In the case of antioxidant activity, organic carrots showed a higher value for DPPH radical scavenging activity (p<0.05). However, there was no significant difference in other antioxidants. Consequently, quality characteristics and antioxidant activities were different between organically and conventionally grown carrots.

• Journal of Mushroom
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• v.20 no.3
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• pp.93-101
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• 2022

Cordyceps militaris mycelium extracts containing high amounts of cordycepin were evaluated in vitro for their anti-inflammatory and tumor cell growth-inhibitory activities. All extracts dose dependently inhibited the increased production of inflammatory mediators including reactive oxygen species (ROS), nitric oxide (NO), and 𝛽-hexosaminidase in lipopolysaccharide (LPS)-stimulated inflammatory cells. All extracts were evaluated for anti-proliferative activity against normal RBL-2H3 cells and diverse types of cancer cell lines, including HCT, MC5-7, U-87MG, AGS, and A549 cells. The extract showed the strongest growth inhibition (IC₅₀ = 28.13 ㎍/mL) relative to vehicle-treated control cells against fibrosarcoma (MC5-7). We have demonstrated anti-inflammatory activity of C. militaris via inhibition of NO, ROS production, and 𝛽-hexosaminidase release in activated cells. C. militaris mycelium extract was also evaluated mechanistically and found to exert six types of anti-cancer activity, confirming its pharmacological potential. Our study suggests C. militaris use as a potential source of anti-inflammatory and anti-cancer agents. C. militaris may also be considered a functional food.

• Journal of Microbiology and Biotechnology
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• v.24 no.4
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• pp.522-533
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• 2014

Bionanotechnology has revolutionized nanomaterial synthesis by providing a green synthetic platform using biological systems. Among such biological systems, microalgae have tremendous potential to take up metal ions and produce nanoparticles by a detoxification process. The present study explores the intracellular and extracellular biogenic syntheses of silver nanoparticles (SNPs) using the unicellular green microalga Scenedesmus sp. Biosynthesized SNPs were characterized by AAS, UV-Vis spectroscopy, TEM, XRD, FTIR, DLS, and TGA studies and finally checked for antibacterial activity. Intracellular nanoparticle biosynthesis was initiated by a high rate of $Ag^+$ ion accumulation in the microalgal biomass and subsequent formation of spherical crystalline SNPs (average size, 15-20 nm) due to the biochemical reduction of $Ag^+$ ions. The synthesized nanoparticles were intracellular, as confirmed by the UV-Vis spectra of the outside medium. Furthermore, extracellular synthesis using boiled extract showed the formation of well scattered, highly stable, spherical SNPs with an average size of 5-10 nm. The size and morphology of the nanoparticles were confirmed by TEM. The crystalline nature of the SNPs was evident from the diffraction peaks of XRD and bright circular ring pattern of SAED. FTIR and UV-Vis spectra showed that biomolecules, proteins and peptides, are mainly responsible for the formation and stabilization of SNPs. Furthermore, the synthesized nanoparticles exhibited high antimicrobial activity against pathogenic gram-negative and gram-positive bacteria. Use of such a microalgal system provides a simple, cost-effective alternative template for the biosynthesis of nanomaterials in a large-scale system that could be of great use in biomedical applications.

• Natural Product Sciences
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• v.22 no.1
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• pp.35-40
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• 2016

The first study on chemical constituents and biological activities of Clausena lansium (Lour.) Skeels (Rutaceae) growing in Vietnam has been done. Phytochemical investigation of n-hexane extract led to the isolation of five compounds: dihydroindicolactone (1), 8-geranyloxy psoralen (2), imperatorin (3), heraclenol (4) and indicolactone (5), in which this is the first report on the presence of dihydroindicolactone (1). Their structures were elucidated based on LC/MS/NMR hyphenated techniques as well as comparison with those of literature data. The n-hexane extract and its subfractions, ethanol 95% extract and several isolated compounds were evaluated for antifungal activity.

• Korean Journal of Community Nutrition
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• v.15 no.5
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• pp.636-647
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• 2010

This study was conducted for researching demand on dietary education of low-level elementary school students and to develop an activity based textbook and a teaching manual on the subject. For necessity of dietary education, 88.8% of subjects answered dietary education is needed. The desirable frequency of the education was once a week (65.7%). The most appropriate time for the education was "school lunch" (37.5%), "special activity" (29.9%), "regular class" (12.4%) and "after school activity" (12.1%). The most preferred educational method was "experiment and practice" (40.1%). The desirable educational materials were "computer materials" (20.7%), "actual objects" (20.1%), "videotapes" (16.5%), "photographs-pictures" (12.2%) and "fairy tales-cartoons" (12.2%). The students wanted dietary information as "cooking" (26.1%), "growth and nutrition" (23.7%) and "right food information" (20.1%). The textbook was composed of five major chapters, which were "Traditional Dietary Culture", "Food", "Dietary Habit", "Hygiene and Environment" and "Cooking". Each major chapter had five to six smaller chapters, adding up to total of 32 chapters. The textbook had fun characters, illustrations, photographs and cartoons to deliver the main theme of each chapter. The textbook was in activity format so that it coul be readily and directly used in actual classes. The teaching manual was composed of background, goals, teaching plans and teaching points. The smaller chapters had learning goals, teaching-learning resources, important points, teaching-learning processes and reference materials. Videos were produced to help cook five snacks in the cooking chapter. Also, "Healthy Song" was created to be used in classrooms. This textbook will be helpful in children's right dietary habits and growth.

• Journal of the Korean Wood Science and Technology
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• v.50 no.4
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• pp.272-282
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• 2022

The essential oil extracted from Citrus × natsudaidai (Yu. Tanaka) Hayata peels is known to have various biological properties. However, the chemical composition of essential oil is influenced by the ripening stages of fruits, which then affects related biological activities. This study investigates the antioxidant activities of essential oils extracted from Citrus × natsudaidai peels at different ripening stages (immature, mature, and overripe). The essential oils were extracted using the hydro-distillation method. As a result of gas chromatography-mass spectrometry (GC-MS) analysis, d-limonene was dominant and was increased as matured. However, 𝛄-terpinene was decreased. The antioxidant properties and their total phenolic content (TPC) were influenced by the ripening stages. The TPC was highest in the immature stage of essential oil (1,011.25 ± 57.15 mg GAE/100 g). 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity was excellent in the immature stage (EC₅₀ = 15.91 ± 0.38 mg/mL). 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity was superior in overripe stage (EC₅₀ = 20.43 ± 0.37 mg/mL). The antioxidant activity measured using ferric reducing antioxidant power (FRAP) assay showed higher values for the essential oils in immaturity (1,342.37 ± 71.07 mg Fe²⁺/100 g). Comprehensively, the essential oil in the immature stage showed the best antioxidant activity. Finally, knowing the chemical composition and antioxidant activity at different ripening stages will provide data for selecting the right fruit.