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        검색결과 12

        1.
        2019.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was carried out using Celluclast 1.5L to increase the content of 2,6-DMBQ and water extractable arabinoxylan in wheat germ extract. Extraction temperatures were 30oC, 45oC and 60oC. The extraction times were 0, 6, 12, 18, 24 and 30 h. The pH of the extract decreased rapidly from 18 h at 30oC in both water- and enzyme-treated extracts. 2,6-DMBQ of water- and enzyme-treated extracts increased with the extraction time. At 30-hour extraction time, enzyme-treated extract increased 27.60% at 30oC extraction temperature than water extraction. Extraction temperatures of 45oC and 60oC were increased by 65.03% and 151.05%, respectively. The highest content of waterextractable arabinoxylan was 15.23±0.08 mg/g when the enzyme was treated at an extraction temperature of 60oC for 30 h. At 30=hour extraction time, enzyme-treated extract increased 7.92% at 30oC extraction temperature compared to water extraction. Extraction temperatures of 45oC and 60oC were increased by 31.20% and 54.38%, respectively.
        4,000원
        2.
        2008.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        심층혼합처리공법에서 원지반과 개량재에 의해 형성되는 혼합처리토에 산업폐기물중 하나인 폐타이어와 기존 토목공사에서 섬유보강재로 사용되고 있는 강섬유를 혼합하여 보강재 및 개량재의 혼합비에 따른 개량체의 압축강도 특성을 파악하기위해 실내실험을 실시하였다. 개량재(시멘트, 시멘트계 고화재)의 경우는 건토중량에 대한 혼합비를 5%, 10%, 15%로 하였으며, 보강재(폐타이어, 강섬유)의 경우는 건토중량에 대한 혼합비를 0.5%, 1%, 2%로 하였다. 그 결과 개량재의 혼합비가 증가함에 따라 일축압축강도는 증가하였으며, 보강재를 첨가한 경우에는 폐타이어분말의 입자크기와 강섬유의 형상비가 작을수록 강도가 크게 나타났으며, 첨가량이 많아질수록 강도가 저하되는 경향이 나타났다.
        4,000원
        3.
        2017.08 서비스 종료(열람 제한)
        The greater horseshoe bat (Rhinolophus ferrumequinum) is distributed throughout Europe, Africa, Australia, and South Asia. It habits mainly in the cave in small groups and forming communities in late spring. It has interesting reproductive behavior because it keeps sperm for a few months in female reproductive tracts and then those sperms attend in fertilization. This breeding pattern is a sperm storage type and belongs to Rhinolophidae or Hipposideridae. The greater horseshoe also habits in Korea. However, the reasons of reproductive behaviors has not much uncovered. In this study the characters of ovary and the levels of steroid hormones were investigated from September to November. The histological, ELISA, and immunohistochemical methods were employed. The pre-ovulatory follicle was detected only at October sample. On the other hand, the blood level of testosterone was not detectable but the levels of 17β-estradiol and progesterone were exist within the detectable range. E2 and P4 levels were peak in October. Besides, the key enzymes for estradiol synthesis, CYP17 and CYP19 were localized in the theca layer and granulosa cells, respectively. October is known as mating time in this species. However, progesterone receptors could not detect at this period. Put together, it is suggested that, the increase of estrogen and the absence of progesterone receptors on preovulatory follicle is the cause of the mating without ovulation. The understanding of the expression regulation in this system will be base of the understanding the anovulation in mammals.
        4.
        2015.07 서비스 종료(열람 제한)
        Radish is one of the most widely consumed vegetable crops in Korea. Root is the major part of radish supplied to the market, thus the size, shape, and quality of radish roots are main targets of breeding programs. Despite of the importance of this crop, the molecular breeding of radish is still in the rudimentary stage. In Golden Seed Project, we aim to establish the molecular breeding program of radish using genome-wide approaches. To this end, we selected inbred lines that have distinctive root traits such as yield, shape, disease resistance, and texture. Single nucleotide variation (SNV) among these lines will be identified based on the low coverage genome sequencing data. These SNVs can be used for finding genomic regions associated with root traits from segregating mapping populations which are also in the middle of development. Korean radish roots are harvested after being grown for only nine weeks. During that period, root biomass reaches to more than two kilograms. While investigating the root growth of radish inbred lines, we found that cytokinin contributes as a key growth regulator that promotes radial growth of radish roots. A difference in growth rates of two distinctive inbred lines was explained by the difference in response to cytokinin. Genes responsive to cytokinin are highly enriched in the cambium, the meristematic cell population that drives radial growth. For comprehensive understanding of genes that affect yields of radish roots, we turned to developing a tissue specific transcriptome data using laser capture microdissection. We expect that the compendium of genomics-based data will help establishing molecular breeding of radish at a fast track.
        5.
        2015.03 KCI 등재 서비스 종료(열람 제한)
        The purpose of the present study was to examine the seminiferous epithelium cycle of Bombina orientalis using a light microscope. The cycle was divided into a total of 10 stages, according to the morphological characteristics of the cells. The spermatogenetic cells included primary spermatogonia, secondary spermatogonia, primary spermatocytes, secondary spermatocytes, spermatid and sperm. At stageⅠ, the primary spermatogonia was located closer to basal lamina of the seminiferous tubule without spermatocyst formations. Especially at the stage Ⅱ, the secondary spermatogonia were located in the spermatocyst. The primary and secondary spermatocytes were found from stages Ⅲ to Ⅵ. The secondary spermatocytes were smaller in size than the primary spermatocytes, but they had thicker nucleoplasm and smaller nuclei. The round-shaped, early sperm cells were formed in stage Ⅶ, and further divided at stage Ⅷ to have more concentrated nucleoplasm before division to matured sperm cells. At stage Ⅹ, the matured sperm cells emerged from the spermatocyst. Considering the above results, this study presented the special characteristics in the generation and type of sperm formation. The germ cell formation occurred in various stages, like the perspectives of Franca et al (1999), ultimately, providing taxonomically useful information.
        6.
        2014.07 서비스 종료(열람 제한)
        A root serves as an essential organ in plant growth by up-taking nutrients and water from soil and supporting the rest of a plant body. Root apical growth and system architecture have been extensively studied because they strongly affect overall plant growth and yields. Some plant species also utilize roots as storage organs. Many of them, including sweet potatoes (Ipomoea batatas), cassava (Manihot esculenta), and radish (Raphanus sativus) are important crops, however their root development has remained elusive. In this study, we characterized radial root growth in the radish and found that it is very similar to the secondary growth in stems. We identified well established cambium zones in the actively growing radish roots. Cell proliferation activities in the cambium zones positively correlated with root growth rates and final yields. Through a comparative analysis with Arabidopsis root expression data, we selected some putative transcription factors whose expression is highly enriched in the cambia and validated their expression in various stages of radish roots. By comparing their expression in two inbred lines with distinctive radial root growth, we identified transcription factors that are involved in morphological differences. More importantly, our investigation suggests that the differences in the root growth of two radish inbred lines are from changes in cytokinin responses. These findings together highlight that radish could serve as an excellent system for studying root crops and that transcriptional regulation and cytokinin signaling are indispensable for the secondary root growth.
        8.
        2013.06 KCI 등재 서비스 종료(열람 제한)
        The seminiferous epithelium cycle and developmental stages of spermatids in Clethrionomys rufocanus were observed under a light microscope. The seminiferous epithelium cycle was divided into 8 stages. Type Ad spermatogonia appeared through all stages. Type Ap, In, and B spermatogonia appeared in stages Ⅰ, Ⅱ, Ⅲ, and Ⅳ. In the first meiosis prophase, the leptotene spermatocytes appeared from stage Ⅴ, the zygotene spermatocytes in stages Ⅰ, Ⅵ, Ⅶ, Ⅷ, the pachytene spermatocytes from stages Ⅱ to Ⅵ, the diplotene spermatocytes in stage Ⅶ. The meiotic figures and interkinesis spermatocytes were observed in stage Ⅷ. Developing spermatids were subdivided into 10 steps, based on the morphological characteristics such as the acrosome formation changes in spermatozoa, nucleus, cytoplasm, and spermiation changes. The C. rufocanus spermatocytogenesis and spermiogenesis results displayed similar results with Apodemus agrarius coreae and A. speciosus peninsulae. Considering all the results, the spermatogenesis may be useful information to analyze the differentiation of spermatogenic cells and the breeding season.
        9.
        2008.12 KCI 등재 서비스 종료(열람 제한)
        The purposes of this study were to investigate visitors' satisfaction and residents' benefits on Hansan Ramie Fabric Ecotourism Festival. The sample of this study was 232. The results of this study were as follows. First, tourists more satisfied with event interesting, variety, and experiences at this festival than residents. Second, It was found that tourists significantly satisfied with understanding of local cultures compared to residents. It was found that tourists spent more money than residents, and the festival contributed to local economy. This study examined only few festival event programs. For the future study, it is necessary to investigate more programs of the festival and examine the determinants factors of visitors' and residents' satisfaction.
        10.
        2005.06 KCI 등재 서비스 종료(열람 제한)
        Thirty-two germplasms of Korean adlay landraces were examined to analyse the genetic relationship through the amplified fragment length polymorphism (AFLP) approach. Total number of AFLP products generated by 12 selective primer combinations was 882. The number of polymorphic fragments by each primer combination greatly varied from 4 to 51 with a mean of 20.3, bands visible on the polyacrylamide gel. A genetic similarity coefficient was used for cluster analysis following UPGMA (unweighted pair grouping method of averages) method. The resulting clusters were represented in the form of a dendrogram. The clustering was not tight in the dendrogram. There was generally no clear grouping of the adlay according to the geographic regions in which germplasms were collected. The present AFLP analysis imply that although Korean adlay displayed a larger amount of AFLP variation within germplasms, the variation was shown independently without reflecting a clinal variation. This study demonstrated that AFLP method can be used to examine the genetic relationships among different germplasms of adlay.
        11.
        2004.12 KCI 등재 서비스 종료(열람 제한)
        The effects of sonication and vacuum infiltration on transformation efficiency was investigated by using immature embryos of Korean wheat as explants. Two Agrobacterium tumefaciens strains, KYRT1 and EHA105, carrying pCAMBIA 1305.1 were used. Transformation efficiency was demonstrated by the detection of β-glucu-ronidase (GUS) activity. GUS expression showed clear difference among Korean wheat cultivars. Geurumil showed higher GUS expression efficiency 79.1~% compared with other cultivars. The effects of the duration of vacuum infiltration and sonication treatment showed a tendency high GUS expression efficiency by their combination. In comparison with other Agrobacterium strains, KYRT1 showed high efficiency in most Korean cultivars.
        12.
        2003.03 KCI 등재 서비스 종료(열람 제한)
        Immature and mature embryos of 18 Korean wheat genotypes were cultured in vitro to develop an efficient method of callus formation and plant regeneration, and to compare the responses of both embryo cultures. Immature and mature embryos were placed on a solid agar medium containing the MS salts and vitamins, 30g/l maltose, 2 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D), and amino acids. The developed calli were maintained on regeneration medium containing MS salts and B5 vitamins, 20 g/l sucrose, and the combination of two plant growth regulators, 6-benzylaminopurine (BAP) and indole-3-acetic acid (IAA). Immature embryos in most genotypes showed high efficiency of callus induction except three genotypes; Eunpamil, Chunggemil, and Namhaemil, and significant differences among the genotypes. Plant regeneration of calli induced from immature embryos showed high efficiency in Geurumil (56.5%), Tapdongmil (50.5%), Gobunmil (45.5%), and Urimil(42.2%). The analysis of variance showed significant differences for regeneration frequency among the genotypes. Mature embryos showed low callus induction frequency compared with that in immature embryos, and significant differences among the genotypes. Plant regeneration of calli induced from mature embryos showed high efficiency in Keumkangmil (33.33%), Tapdongmil(28.13%), and Geurumil (27.78%). The analysis of variance showed significant differences for plant regeneration frequency among the genotypes.