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        검색결과 53

        36.
        2018.10 구독 인증기관·개인회원 무료
        We have investigated the developmental characteristics of super mealworm on different temperatures. The test was conducted with four different temperatures of 25℃, 27℃, 30℃, and 33℃. In developmental period of 1 to 18 instars of four temperatures, 30℃ showed the shortest developmental period as 120.0±5.8 days, and 33℃ (132.6±10.7 days), 27℃ (136.5±9.2 days), 25℃ (156.7±7.5 days) in the following order. The death rate of 33℃ larvae was 2.7- 3.3 times higher than that of other temperatures. The lower temperatures tended to show the longer larval developmental period except 33℃. In the body weight, 30℃ showed the heaviest body weight and 27℃, 33℃, 25℃ in the following order. The head capsule, body capsule and body length also showed a similar tendency with body weight. The 88.8% of prepupa time of super mealworm was 16-18 instars. The longer prepupa time was accompanied by the lower temperature. In average prepupal period of 15-18 instars, 27℃ was 18.8±1.9 days, 18.8±2.3 days in 30℃, 23.0±2.4 days in 33℃, 23.1±2.9 days in 25℃. The average of pupal period of female and male in 25℃- 33℃ was 11.1±2.2 days and 11.6±2.4 days, respectively. In conclusion, the most suitable rearing temperature of super mealwarm was turned out as 30℃.
        37.
        2018.05 구독 인증기관·개인회원 무료
        The ride quality (i.e. smoothness) is a key factor for evaluating the construction quality of expressway asphalt pavement. Conventionally, three paving devices are widely used to control the surface layer thickness: leveling sensor (i.e. LS), short-range-surfacing-contact-ski (i.e. SSCS) and long-range-surfacing-contact-ski (i.e. LSCS). However, each of these levelling tools presents one major drawback. In the case of LS, if the original sub-layer evenness is poor, the final asphalt pavement surface and its smoothness will be negatively affected. The SSCS cannot assure satisfactory smoothness when relatively long paving section (in the order of 10 km) are paved. While the LSCS would reduce the drawback of the SSCS, its weight on the one hand and its length on the other discourage its use in the paving site especially for curved sections. In this paper, a next generation pavement smoothness leveling equipment, known as non-contact-digital-ski (i.e. NCDS) was implemented, evaluated and compared to the conventional equipment leveling device. The international Roughness Index (IRI m/km) was measured on sections paved with and without NCDS and the results visually and statistically compared. In addition, for the same sections, the modulus of the pavement layers was computed and compared by means of Falling Weight Deflectometer (i.e. FWD). It was observed that when NCDS is used for asphalt pavement overlay of existing concrete pavement, significant improvement in IRI (i.e. IRI<1.0m/km) and consistently uniform elastic modulus could be achieved compared to the conventional levelling and paving method.
        38.
        2017.11 구독 인증기관·개인회원 무료
        In plants, starch is the main carbohydrate reserve and an important ingredient in human nutrition. Nutritionally, starch is classified into rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS) based on the rate and degree of digestion. RS escapes enzymatic digestion in the small intestine, but in the large intestine microbial flora may ferment some RS. Malic acid is C4 carboxylic acid with two carboxyl groups. It is well known to take from 69% up to 92% of all organic acids in grape berries and leaves and is naturally produced by many organisms without showing any nutritional harm. However, properties of malic acid treated starch has not been clearly reported. The objectives of this study were to investigate the influence of pH value on low-digestible malate starch formation and digestibility in relation to structural properties of corn starch. Different pH values (1.5-8.5) of 2 M malic acid solution were reacted with corn starch in a forced-air oven at temperature of 130°C for 12 hr. Using FT-IR, carbonyl groups were detected in malate starch, indicating the formation of cross-linking by esterification. Increasing pH value of malic acid-treated sample from 1.5 to 8.5 showed an increase in degree of substitution (DS) and resulted in increase in the RS content from 18.2 to 74.8%, which was maintained after gelatinization. The granular structure of malate starches was not destroyed, and the starches maintained birefringence. This malate starch could be utilized in heat processed foods such as bread and cookies as well as in the products with reduced calories.
        39.
        2017.11 구독 인증기관·개인회원 무료
        Starch is classified as fast digestible starch (RDS), slowly digestible starch (SDS) and resistant starch (RS) depending on digestibility. RS can avoid enzymatic digestion in the small intestine, but microbes in the large intestine can ferment some RSs. The purpose of this study was to investigate the structural characteristics of low digestible starch by malic acid mutation in rice, corn and potato starch. Rice, corn and potato starch were treated with a 2M malic acid solution in a forced air oven at 130 ° C for 12 hr. Using FT-IR, carbonyl groups were detected in malate starch, indicating the formation of cross-linking by esterification. And, Using X-ray, diffractograms of malic acid-treated starch. In the micrographs, malate treated corn and potato starch granules were marked with elliptical or polygonal shapes and starch retained birefringence. Through microscopic observe in morphology of starch granules, Microscopic observation did not reveal any changes in morphology of starch granules. The modified starches had higher RS than the control and native starch. RS content of maltitized rice, corn and potato starch was 87.6%, 89.8% and 64.8%, respectively. Malic acid treated RS was maintained after the cooking process. The RS of substituted starches increased with increasing degree of substitution. These results suggest that the increase in RS content by malic acid treatment is caused by the change in the structure. And the highest resistant starch content (86.7%) was found at pH 1.5, 2M of malic acid treated corn starch. Malic acid-treated starch can be used as heat-stable and low-digestible starch containing food ingredients.
        40.
        2016.10 구독 인증기관·개인회원 무료
        In mature oocytes, maturation promoting factor (MPF) activity is playing important roles in arrest at M-phase and its continuous phenomenon, oocyte aging. In most mammals, metaphase II oocytes show high MPF activity and have been used as ooplasts in somatic cell nuclear transfer (SCNT). Caffeine has been found to regulate MPF activity in mammalian oocytes. Caffeine inhibits p34cdc2 phosphorylation and increases MPF activity. The present study investigated the effects of caffeine treatment during last 4 hours of in vitro maturation (IVM) on oocyte maturation and embryonic development after parthenogenesis (PA) and SCNT. The IVM medium was medium-199, 10% (v/v) PFF, cysteine, pyruvate, epidermal growth factor, kanamycin, insulin, and hormones. Immature oocytes were matured in IVM medium without or with 2.5 mM caffeine during the last 4 hours of IVM. The in vitro culture medium for embryonic development was porcine zygote medium-3 containing 0.3% (w/v) bovine serum albumin. Nuclear maturation (83.6–87.2%) and intraoocyte glutathione contents (0.9–1.0 pixels/oocyte) of oocytes were not influenced by the caffeine treatment. The membrane fusion of cell-cytoplast couplets (75.5–76.5%) and cleavage (85.4–86.2%) were also not altered by the caffeine treatment. However, caffeine-treated oocytes showed higher (P<0.05) blastocyst formation after SCNT (47.5 vs. 34.3%) than untreated oocytes. Our results demonstrate that caffeine treatment during last 4 hour of IVM improves the developmental competence of SCNT embryos probably by influencing MPF activity.
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