• Herbal Formula Science
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• v.30 no.4
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• pp.259-267
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• 2022

Objectives : In this study, erythrocyte micronucleus test of pomace Schisandra chinensis extracts was conducted in order to up-cycling to a high value-added industry using by-products discarded in the production process of Schisandra chinensis products and active ingredients such as dibenzocyclooctadiene lignans in Schisandra chinensis. Methods : The micronucleus test was performed according to the 'OECD Guidelines'. Including the negative control group(0 mg/kg) and the positive control group(CPA 70 mg/kg), pomace Schisandra chinensis extracts were orally administered to ICR mouse at doses of 500, 1,000, and 2,000 mg/kg. After sacrificing the experimental animals bone marrow cells were collected and micronucleated polychromatic erythrocyte were counted. And genetic toxicity was confirmed according to the frequency of micronucleus. Results : As a result of the micronucleus test, there were no changes in body weight, clinical signs, or death in any group. But, a significant increase was observed in the frequency of micronucleated polychromatic erythrocyte among polychromatic erythrocytes in the positive control group administered with CPA compared to the negative control group(p<0.05). Whereas, no significant increase was observed in the group administered with pomace Schisandra chinensis extracts compared to the negative control group. Conclusions : Pomace Schisandra chinensis extracts did not induce micronucleus in bone marrow cells of ICR mouse up to a concentration of 2,000 mg/kg, and it was judged that no genetic toxicity was observed.

• Restorative Dentistry and Endodontics
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• v.33 no.1
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• pp.9-19
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• 2008

The purpose of this study was: (1) to compare nanoleakage patterns of a conventional 3-step etch and rinse adhesive system and two experimental hydrophobic adhesive systems and (2) to investigate the change of the nanoleakage patterns after load cycling. Two kinds of hydrophobic experimental adhesives, ethanol containing adhesive (EA) and methanol containing adhesive (MA), were prepared. Thirty extracted human molars were embedded in resin blocks and occlusal thirds of the crowns were removed. The polished dentin surfaces were etched with a 35 % phosphoric acid etching gel and rinsed with water. Scotchbond Multi-Purpose (MP), EA and MA were used for bonding procedure. Z-250 composite resin was built-up on the adhesive-treated surfaces. Five teeth of each dentin adhesive group were subjected to mechanical load cycling. The teeth were sectioned into 2 mm thick slabs and then stained with 50 % ammoniacal silver nitrate. Ten specimens for each group were examined under scanning electron microscope in backscattering electron mode. All photographs were analyzed using image analysis software. Three regions of each specimen were used for evaluation of the silver uptake within the hybrid layer. The area of silver deposition was calculated and expressed in gray value. Data were statistically analyzed by two-way ANOVA and post-hoc testing of multiple comparisons was done with the Scheffe's test. Silver particles were observed in all the groups. However, silver particles were more sparsely distributed in the EA group and the MA group than in the MP group (p < .0001). There were no changes in nanoleakage patterns after load cycling.

• Journal of Korean Elementary Science Education
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• v.35 no.3
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• pp.336-347
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• 2016

The purpose of this study is to analyze the effects of elementary science instruction applying a Brain-Based Evolutionary (ABC-DEF) approach using Rapid-cycling Brassica rapa (RcBr) on the interests of elementary school students. For this study, two elementary school classes in Seoul and one elementary school class in Gyeonggi-do were selected. Comparison group received instruction using textbook and teacher's guidebook. A class taught using only brain-based evolutionary approach is experimental group A, and a class taught through brain-based evolutionary approach using RcBr is experimental group B. In order to analyze the quantitative differences about the interests of students, three kinds of test were administered to the students: 'Applied Unit-Related Interests', 'Follow-up Interests' and 'Interests in the observation material'. To get more information, qualitative data such as portfolios and interviews were analyzed. The major findings are as follows. First, for the test of applied unit-related interests, a statistically significant difference was found between comparison group and experimental group A, and between comparison group and experimental group B. As the results of interviews, the students have shown that the intensified exploration activities on plant in Brain-Based Evolutionary approach applied to experimental groups A and B had a positive effect. Second, for test of follow-up interests, we classified the students' follow-up interests into three types: extended-developed-deepened (EDD) type, simply expanded-maintained (SEM) type, and stopped or decreased (SD) type. Both experimental group A and experimental group B showed the highest percentage of EDD. Also, observation journal applying the evolutionary process (DEF) showed a positive effect on the students' interest. Comparison group showed the highest percentage of SEM. Third, for test of applied interests in the observation material, a statistically significant difference was found between comparison group and experimental group A, and comparison group and experimental group B. Experimental group B using RcBr showed the highest average score, while experimental group A showed a higher score than comparison group. Based on these findings, educational implications of Brain-Based Evolutionary approach and using RcBr are discussed.

• Korean Journal of Materials Research
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• v.26 no.5
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• pp.258-265
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• 2016

Fluorine-doped tin oxide (FTO) nanoparticles have been successfully synthesized using ultrasonic spray pyrolysis. The morphologies, crystal structures, chemical bonding states, and electrochemical properties of the nanoparticles are investigated. The FTO nanoparticles show uniform morphology and size distribution in the range of 6-10 nm. The FTO nanoparticles exhibit excellent electrochemical performance with high discharge specific capacity and good cycling stability ($620mAhg^{-1}$ capacity retention up to 50 cycles), as well as excellent high-rate performance ($250mAhg^{-1}$ at $700mAg^{-1}$) compared to that of commercial $SnO_2$. The improved electrochemical performance can be explained by two main effects. First, the excellent cycling stability with high discharge capacity is attributed to the nano-sized FTO particles, which are related to the increased electrochemical active area between the electrode and electrolyte. Second, the superb high-rate performance and the excellent cycling stability are ascribed to the increased electrical conductivity, which results from the introduction of fluorine doping in $SnO_2$. This noble electrode structure can provide powerful potential anode materials for high-performance lithiumion batteries.

• Journal of Animal Environmental Science
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• v.1 no.2
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• pp.155-164
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• 1995

Despite considerable progresses made in our understanding of environmental fate of pollutants stemming from animal production systems, relatively little is known about the processes and mechanisms regulating their dispersement (via emission) into and deposition from the earth's atmospheric system. Here we present and summarize up-to-date knowledge on this topic with a main emphasis on their origin, physico-chemical characteristics, and geochemical distribution behavior.

• Journal of Plant Biotechnology
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• v.3 no.1
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• pp.27-31
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• 2001

New types of cytoplasmic male sterility in Brassica species would be very useful for the production of F$_1$, hybrid seeds. Leaves and stems of rapid cycling stock of B.juncea (CrGC4-3) containing Anand CMS were used as experimental materials for plant regeneration from protoplast culture. Very high plant regeneration rate (85%) was found in the Kao & Michayluk medium supplemented with 2 mg/L zeatin, 0.5 mg/L BAP, and 1 mg/L NAA when only leaf, not stem, segments were cultured. Protoplasts were isolated from leaves using mixtures of enzymes (1% Cellulycin, 0.5% Macerozyme) in 0.4 M mannitol and 50 mM $CaCl_2$.$2H_2$O. Mcrocalli induced from protoplasts were transferred to the shoot regeneration medium containing 2 mg/L BAP, 2 mg/L zeatin, and 0.5 mg/L NAA. After 60 days of initial protoplast culture, regenerated plantlets were obtained, acclimatized, transplanted into the pots, and grown up to the flowering stage.

• Journal of Electrochemical Science and Technology
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• v.2 no.3
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• pp.157-162
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• 2011

We report a simple route for synthesizing multi-dimensional structured silicon anode materials from commercially available bulk silicon powders via metal-assisted chemical etching process. In the first step, silver catalyst was deposited onto the surface of bulk silicon via a galvanic displacement reaction. Next, the silver-decorated silicon particles were chemically etched in a mixture of hydrofluoric acid and hydrogen peroxide to make multi-dimensional silicon consisting of one-dimensional silicon nanowires and micro-scale silicon cores. As-synthesized silicon particles were coated with a carbon via thermal decomposition of acetylene gas. The carbon-coated multi-dimensional silicon anodes exhibited excellent electrochemical properties, including a high specific capacity (1800 mAh/g), a stable cycling retention (cycling retention of 89% after 20 cycles), and a high rate capability (71% at 3 C rate, compared to 0.1 C rate). This process is a simple and mass-productive (yield of 40-50%), thus opens up an effective route to make a high-performance silicon anode materials for lithiumion batteries.

• The KIPS Transactions:PartC
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• v.9C no.2
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• pp.221-226
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• 2002

Cycling Packet Dropping mechanism we proposed in this paper adaptively drops packets, as predicting traffic pattern between each cycle. Therfore the proposed mechanism makes up for the drawback of RIO mechanism and minimizes errors being capable of predicting in Dynamic and Strict Packet Dropping mechanism. And we executed a simulation and analyzed the throughput and packet drop rate based on the Sending Drop Precedence changing dynamically depending on the network traffic. The results show that the proposed mechanism provides better performance on drop precedence levels and stricter drop precedence policy for AF class.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.12
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• pp.3046-3060
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• 2012

Low power listening (LPL) MAC protocols based on duty-cycling mechanism have been studied extensively to achieve ultra low energy consumption in wireless sensor networks (WSNs). Especially, recent ACK-based LPL schemes such as X-MAC employ strobe preambles and an early ACK, and show fair performances in communications and energy efficiencies. However, the state-of-the-art ACK-based LPL scheme still suffers from collision problems due to the protocol incompleteness. These collision effects are not trivial and make WSNs unstable, aggravate energy consumptions. In this paper, we propose two novel schemes; (i) ${\tau}$-duration CCA to mitigate the collision problem in ACK-based LPL MAC protocols. (ii) Short Preamble Counter (SPC) to conserve more energy by reducing unnecessary overhearing. We demonstrate the performance improvement of our scheme via a mathematical analysis and real-time experiments. Both analysis and experimental results confirm that our proposed scheme saves energy by up to 36% compared to the naive ACK-based LPL MAC protocol thanks to ${\tau}$-duration CCA and SPC.

• Journal of The Korean Digital Architecture Interior Association
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• v.13 no.4
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• pp.25-32
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• 2013

The green building is one of biggest factors to go the goal of energy saving and environmental conservation, reduction of energy consumption, friendly energy technology, recycling of resource, and environmental pollution reduction technology. The purpose of these green buildings realized by the energy-saving technology such as the exterior materials or curtain wall system. The curtain wall system is a element that come to insulated portions of building envelope that results in heat loss. The purpose of this paper is to carried out mock-up tests for exterior wall used in autoclaved lightweight concrete panels in green building practices. Mock-up test execute a mixed process between standard test procedure and complex test procedure based on AAMA 501(American Society for Testing and Materials) and ASTM 283, ASTM 330(American Society for Testing and Materials). In results, tests meet the requirements that grant values in steps of procedures provided on ASTM and AAMA. ALC panel is suitable for a exterior wall product to be gratified thermal cycling performance and structural capacity, deflection(H/200) and lateral displacement(H/50), for curtain walls.