This study was carried out to investigate the antioxidant activities and the contents of antioxidant compounds in extracts derived from 23 medicinal crops. Dried plant materials were extracted by 80% methanol and the extracts were used to experiment. The levels of total phenolic compounds were much higher in Oenothera biennis, Houttuynia cordata, Cedrela sinensis, Rhus javanica, Artemisia annua, Reynoutria sachalinensis, and Dendropanax morbifera compared with other crops. On the other hand, the total phenolic compound levels in Carthamus tinctorius, Polygonum multiflorus, Ginko biloba, Solanum nigrum, and Saposhnikovia divaricata were relatively low. The total flavonoid contents were highest in H. cordata, followed by D. morbifera, A. annua, A. continentalis and O. biennis. DPPH activity was significantly higher in A. annua, R. javanica, C. sinensis, D. morbifera and O. biennis, and ABTS activity was significantly higher in R. javanica, C. sinensis, O. biennis, R. sachalinensis, A. annua, and D. morbifera than other plants. These results suggest that O. biennis, A. annua, R. javanica, D. morbifera, and R. sachalinensis can be utilized as food additives and natural antioxidants due to their strong antioxidant activity.

친전자성 치환반응을 통하여 제조된 술폰화 단량체와 비(非)술폰화 단량체의 직접 중합법을 통하여 서로 다른 술폰화도를 나타내는 술폰화 폴리아릴에테르술폰 공중합체를 합성하고, 이들로부터 직접 메탄올 연료전지용 이중층(層) 고분자 전해질 막을 제조하였다. 우수한 이온 전도특성을 나타내는 술폰화도 50%의 공중합체를 사용하여 전해질 막의 모체(母體) 전도층을 제조하고, 이들의 한쪽 표면에 술폰화도 10%의 공중합체를 도포한 후 건조하여 낮은 메탄올 투과 특성의 코팅층을 형성시켰다. 도포되는 공중합체의 질량비를 5~20%로 조절함으로써 코팅 층 두께에 따른 전해질 막의 특성 변화를 고찰하였으며, 형성된 코팅 층을 막-전극 접합체의 음극 면에 접합시켜 운전 시 메탄올 연료와 직접 접촉하도록 하였다. 이중층 형성 공정을 통하여, 단일 전해질 막과 동등한 수준의 이온 전도 특성을 유지하면서도, 전해질 막을 통한 메탄올 투과 특성이 현저히 개선된 우수한 효율의 고분자 전해질 막 제조가 가능하였다. 작동 온도 60°C, 2 M의 메탄올 공급 환경에서 수행된 연료 전지 성능 평가 결과, 막-전극 접합체 출력 밀도는 5%의 질량비에서 최대 134.01 mW/cm2였으며, 이로부터 상용 나피온 115 대비 105.5%의 향상된 성능 효율을 확인할 수 있었다.

Robots are used in early childhood education as a new instructional media, and educational activities using robots have been increased. So the purpose of this study is to investigate the effect of educational activities using hands-on robots on logic-mathematical knowledge and creative problemsolving ability of young children. The total number of subjects was 43, and they were all five-year-old children. The experimental group and control group did activities with hands-on robots and general free activities, respectively. Results using ANCONA have shown that the activities with hands-on robots positively affected logic-mathematical knowledge and creative problem-solving ability of young children. These meaningful results have shown the possibility of early childhood educational use as the effectiveness of hands-on robots has come out.

Background : Recently, there have been dynamic researches conducted on stevia as natural sweetener subtitute for sugar, However, Researches related to harvest period and parts of plant in stevia are few. Therefore, this study was conducted to select optimum harvest time and parts by measuring the natural sweeteners contents and analyzing antioxidant materials and activity according to harvest times, parts of plant. Methods and Results : Stevia was cultivated in plastic house, The leaves were harvested from April to October and the stem were only harvest in July and September. Stevia leaves and stems were extracted using high temperature and pressure extraction: Dried stevia leaves of 5g were added by 100ml of distilled water equivalent to 20 times of dry weight, and the mixture were extracted by autoclave at 121℃ for 15min. The contents of Rebaudioside A and Stevioside of stevia leaves harvested from April to October showed a tendency to increase gradually from July to October as the temperature increased, but the contents of rebaudioside A and stevioside decreased slightly in August due to excessively high temperature. The extraction yield of stevia leaves were highest in October and September, and there was no significant difference in the other period. In the stevia stems, the extraction yield was lower than that of stevia leaves in general regardless of harvest time. Total phenolic contents and flavonoid contents according to harvest time showed little difference among treatment. Conclution : stevia leaves were better than stevia stems regarding the use of rebaudioside A and stevioside as natural sweeteners. Also, it was confirmed that the stevia leaves of July, September and October, except for the high temperature period of August, had superior in quality and quantity.

Background : Stevia extracts were reported to contain steviol glycosides like stevioside and rebaudioside A, as well as various polyphenol compounds. However, there are many difference in researchers with extract methods, considering components and antioxidant activity. This study was conducted to select optimum extraction method based on reported methods by measuring the natural sweeteners contents, analyzing antioxidant materials and activity according to extraction methods. Method and Results : Stevia leaves were extracted through vacuum extraction, hot water extraction, soxhlet extraction, high temperature and pressure extraction and ultrasonic extraction to identify the high extraction efficiency. Extraction yield was high in order of hot water extraction, soxhlet extraction, high temperature and pressure extraction and ultrasonic extraction except for vacuum extraction and contents of rebauduoside A and stevioside in stevia leaves was highest in high temperature and pressure extraction followed by vacuum extraction, soxhlet extraction, hot water extraction and ultrasonic extraction. Also, total phenolic contents and flavonoid contents were highest in high pressure extraction and vacuum extraction according to extraction methods. But DPPH radical scavenging activity was highest in ultrasonic extraction and tended to be rather low in high temperature and pressure extraction (ultrasonic extraction > hot water extraction > high pressure extraction > soxlet extraction > vacuum extraction) and there wa no difference in ABTS radical scavenging activity among extraction methods. Conclusion : The high temperature and pressure extraction is considered to be a suitable method for extracting stevia leaves because it showed high extraction yield and had high contents of rebaudioside A, stevioside, total phenolic contents and flavonoid contents.

Background : Currently, obesity and adult diseases as a result of sugar intake have been a consistent problem in Korea. Natural sweeteners as sugar substitutes have many advantages over sugar as a small quantity. Therefore, this study was conducted to investigate possibility of industrialization as food additives by using the nature sweetness components of stevia (Stevia rebaudiana Bertoni). Method and Results : Stevia was cultivated in a plastic house. The leaves and stems were harvested at October. They were ground into fine powder using a mill, and were extracted by high temperature and pression extraction method. The extracts were evaporated under vacuum and lyophilized. Three strawberry cultivars of ‘Seolhyang’, ‘Maehyang’, and ‘F22-196’ were cultivated in a plastic house and were harvested from March to May. The fruits harvested were stored at 50℃ until processing. In order to test the processing suitability of stevia extract, the characteristics of the three strawberry varieties (line) were investigated. As a result, the ‘F22-196’ line, which was bred as a processing strawberry, generally contained more antioxidant materials and activity than those of ‘Maehyang’ and ‘Seolhyang’ varieties. Comparing the sugar contents which affects the quality of strawberry jam, the average sugar contents of ‘F22-196’ line was higher than 'Maehyang' and 'Seolhyang' varieties. In the preparation of strawberry jam using ‘F22-196’, strawberry jam was prepared by adding only sugar or stevia extract powder, which was 1/100 of the amount of the sugar in only sugar strawberry jam, to the sensory test. As a result, we identified that sugar jam and stevia jam added stevia extract showed 50 : 50 at the sensory test and stevia jam does not make a difference to the marketing jam at the point of view of general consumers. Conclusion : ‘F22-196’ line represented the best quality for strawberry jam in test caltivars. Stevia powder is judged to be used as a sweetener of sugar substitutes in the production of strawberry jam and processing food.

Background : This study was carried out to select the medicinal crop having the superior antimicrobial activity against 5 microorganisms among 20 medicinal crops. Methods and Results : Dried plants were extracted by methanol. The extracts of each plant were evaporated under vacuum. The extracts were absorbed into 50㎕ of each extracts on paper disk and diameter of clear zone was confirmed around the colony. The results showed that diameter of the clear zone against Escherichia coli was the widest in Rhus javanica(R. javanica, 16mm), followed by Evening primrose(14.5mm), Chinaberry(13mm) and Giant knotweed(11mm). Also, diameter of the clear zone against Vibrio parahaemolyticu was the widest in R. javanica(26mm), followed by Evening primrose(21mm), chrysanthemum flower(19mm), Chinese pepper(16.5mm), Chidii rhizoma(11.5mm), Curly dock(11.5mm), Comfrey(11mm), Black nightshade(11mm) and Mustard(10mm). Likewise, diameter of the clear zone aginast Proteus mirabilis was the widest in R. javanica(11.5mm), followed by Chinaberry(11mm). Specially, diameter of the clear zone against Bacillus subtilis and Staphylococcus aureus was identified only in R. javanica(12mm and 11mm, respectively). Therefore, R. javanica showed the best excellent antimicrobial activity among 20 medicinal crops. Total phenolic and flavonoid contents of R. javanica were 2,725mg/100g and 30.2mg/100g respectively. DPPH and ABTS activity of R. javanica were 92.6% and 98.4%, respectively. Conclusion : These results suggest that R. javanica can be utilized as natural food additives and antioxidant materials because of its powerful antimicrobial action and the high antioxidant activity.

Background: This study determined the effects of mulching, an environment friendly organic cultivation method, on antioxidant compound contents and growth in Codonopsis lanceolata, commonly known as Deodeok. Methods and Results: C. lanceolata was treated by mulching with several different methods (a non-woven fabric, biodegradable film, or rice husks) and also treated with hand weeding. A non-treatment plot was used as a control. The growth and levels of weed control in C. lanceolata were better in plants cultivated under mulching treatments (non-woven fabric, biodegradable film, and rice husks) than in those under non-mulching treatments (hand weeding and non-treatment). The contents of antioxidant compounds, such as total flavonoids, phenolics, and anthocyanins, were highest under the biodegradable film treatment, followed by the nonwoven fabric treatment, rice husks treatment hand weeding, and non-treatment. There were identifiable differences in DPPH and ABTS activity in comparison to antioxidant compound content by solvent fractions. Mulching treatments resulted in higher DPPH scavenging activity in water and ethyl ether fractions and ABTS scavenging activity in n-butanol fractions than in other fractions, as opposed to hand weeding and non-treatment groups, although total activity of DPPH and ABTS did not increase with mulching treatments. Conclusions: Mulching C. lanceolata with biodegradable film and non-woven fabric is an effective method for improving plant growth and inhibiting the occurrence of weeds as well as for increasing antioxidant compound content and altering antioxidant activity.

Background : This study was conducted to determine the effects of mulching, an environmentally friendly organic cultivation method, on antioxidant compounds and growth in Codonopsis lanceolata. Methods and Results : C. lanceolata was treated by mulching with a non-woven fabric, biodegradable film, or rice husks, as well as hand weeding, and non-treatment. The growth and levels of weed control in C. lanceolata were better in plants cultivated under mulching treatments (non-woven fabric, biodegradable film, and rice husks) than under non-mulching treatments (hand weeding, non-treatment). The contents of antioxidant compounds, such as total flavonoids, phenolics, and anthocyanin, were highest under biodegradable film treatment, followed by non-woven fabric treatment, rice husks treatment, hand weeding, and non-treatment. DPPH and ABTS activity were able to identify to have differences their activity in comparison to antioxidant compounds content by solvent fractions. Mulching treatments produced a higher activity in water and ethyl ether fractions for DPPH scavenging activity and in n-butanol fractions for ABTS scavenging activity compared to other fractions, although total activity of DPPH and ABTS were not increased with mulching treatments. Conclusion : Mulching C. lanceolata with biodegradable film and non-woven fabric is an effective method for improving plant growth and inhibiting the occurrence of weeds as well as increasing antioxidant compound content and changing of antioxidant activity.

Background : This study was carried out to investigate the antioxidant activities and the contents of antioxidant compounds in extracts derived from 24 medicinal crops. Methods and Results : Dried plant materials were extracted by methanol. The extracts of each plant were evaporated under vacuum and stored in deep freeze at -20℃ until use. The levels of total phenolic compounds were much higher in Evening primrose, Houttuynia cordata, Chinaberry, Sumac, Gaeddongssuk, Giant knotweed and Dendropanax morbifera compared with other crops. On the other hand, the total phenolic compound levels in Safflower, Fleeceflower root, Gingko, Black nightshade, Saposhinikovia root, and Maize woody pith were relatively low. The total flavonoid contents were highest in Houttuynia cordata, followed byDendropanax morbifera, Gaeddongssuk, Aralia cordata and Evening primrose. DPPH activity was significantly higher in Gaeddongssuk, Sumac, Chinaberry, Dendropanax morbifera and Evening primrose, and ABTS activity was significantly higer in Sumac, Chinaberry, Evening primrose, Giant knotweed, Gaeddongssuk and Dendropanax morbifera than other plants. The antioxidant activities dertermined in all assays positively correlated with the total phenolic compoubds (0.619≤ r ≤0.895) and flavonoid contents (0.488≤ r ≤0.619) as well as among themselves (r=0.900). Conclusion : These results suggest that Evening primrose, Gaedongssuk, Sumac, Dendropanax morbifera, and Giant knotweed can be utilized as food additives and natural antioxidants due to their strong antioxidant activity.