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        검색결과 690

        513.
        2011.02 서비스 종료(열람 제한)
        Since cable members are the major structural components in cable bridges, they should be properly inspected for surface damage as well as inside defects such as corrosion and/or breakage of wires. Starting from August 2010, a new research project supported by Korea Ministry of Land, Transportation Maritime Affairs (MLTM) was initiated to develop the cable inspection robot. In this study, only the vision-based surface damage detection system based on image processing techniques is addressed. The damage detection algorithm combines some image enhancement techniques with principal component analysis (PCA) to detect damages on cable surface. The images from three cameras attached to the cable climbing robot are wirelessly transmitted to the server computer at the cable support. They are processed with image enhancement method together with noise removal technique to improve overall image quality. Then they are projected into PCA sub-space. Finally, the Mahalanobis square distances of the projected images to all sample patterns are calculated. The smallest distance is found to be the match for the input image. The proposed damage detection algorithm was verified through laboratory tests on three types of cables.
        514.
        2010.12 KCI 등재 서비스 종료(열람 제한)
        For sensitive and accurate gene expression analysis, normalization of gene expression data against housekeeping genes is required. There are conventional housekeeping gene (e.g. ACT) that primarily function as an internal control of transcription. In this study, we performed an in silico analysis of 278 rice gene expression samples (GSM) in order to identify the gene that is most consistently expressed. Based on this analysis, we identified novel candidate housekeeping genes that displayed improved stability among the cross experimental conditions. Furthermore four of the most conventional housekeeping genes were included in our 30 other housekeeping genes among the most stable genes. Therefore, these 30 genes can he used to normalize transcription results in gene expression studies on rice at a broad range of experimental conditions.
        516.
        2010.09 서비스 종료(열람 제한)
        This study is to survey the ultrastructure of gamete cells and micropyle of pre-fertilized and post-fertilized eggs after HCG hormone treatment by transmission and scanning electron microscopy (TEM and SEM) in E. akaara, E. bruneus and E. septemfasciatus. These fishes are economical importance species for Jeju coastal area resources. In spite of its an importance resources, details studies on the ultrastructural aspects of gamete cells for its reproductive biology have not been undertaken. Morphological features of ovulation process have been studied during its normal occurrence in the reproductive cycle of these fish by light microscopy. Moreover, it has been studied for many years to induce spawning by environmental factors (day length, water temperature etc) or injection of HCG for ovulation in these species. Studies on the micropyle was mainly focused on the eggs of insects, fresh water and a few sea water fishes. Micropylar structure of fish displays morphological characteristics of interspecies-specific by inhabitant environment and spawning feature. On the other hand, it is an importance cue for a taxonomical indicator and identification fish eggs. SEM studies were performed on growing and mature oocytes obtained by stripping and cannulation from 3 grouper species sampled between July and August in spawning season. The outer layer of chorion of preovulatory growing stage oocytes could be divided into four layers; zona pellucida, follicular cell layers consisted of granulosa and thecal cells layer and the most outer ovigerous lamella. Ovulation process of mature stage oocytes initiated by rupture of ovigerous lamella and ovulated by contraction of follicular cell layers. Besides, the micropylar shape of ripe stage oocytes in E. akaara, E. bruneus and E. septemfasciatus presented volcano or crateriform-like cylindrical form. Internal structure of micropylar vestibule displayed cylindrical clockwise 8 or 10 spiral arrangement structure in these species. The micropyle diameter and apparatus at the animal pole differ significantly among the 3 species. The difference in their diameters suggests species-specific in the correlation between spermatozoal head size and micropylar diameter for polyspermy prevention and hybridization during fertilization. Besides, after artificial fertilization, the vestibule morphologically transformed into dom-shape and pillar-shape for fertilization cone formation. Pores of various sizes in the 3 grouper species were somewhat regularly distributed in concentric circles only around the micropyle. In particular, large pores had numerous gill filament-shaped projections connected to oolemma. These structures are suggested to be related to gas exchange, osmoregulation, and micronutrient influx or efflux between eggs and water during fertilization and egg development. In addition, spermatozoa ultrastructure was examined in 3 grouper species. TEM investigation revealed that, in all species, spermatozoa display a round head, a nucleus containing highly condensed, filamentous chromatin clusters, no acrosome, a short midpieces consisting of numerous mitochondria and the proximal and distal centrioles and a flagellum exhibiting the typical axoneme structure (9+2). Especial, both E. akaara and E. bruneus display regular laternal fins in flagella, but in E. septemfasciatus, no fins in flagella with hook shape tails.
        517.
        2010.08 KCI 등재 서비스 종료(열람 제한)
        TILLING (Targeting Induced Local Lesions IN Genomes) is broadly regarded as an excellent methodology for reverse genetics applications. Approximately 15,000 M3 TILLING lines have been developed via the application of gamma-ray irradiation to rice seeds (cv. Donganbyeo), followed by subsequent selections. In an effort to evaluate the genetic diversity of the TILLING population, we have employed the AFLP multiple dominant marker technique. A total of 96 (0.64%) TILLING lines as well as Donganbyeo were selected randomly and their genetic diversity was assessed based on AFLP marker polymorphisms using 5 primer combinations. An average of 100.4 loci in a range of 97 to 106 was detected using these primer combinations, yielding a total of 158 (31.4%) polymorphic loci between Donganbyeo and each of the 96 lines. A broad range of similarity from 80% to 96% with an average of 89.4% between Donganbyeo and each of the 96 lines was also observed, reflecting the genetic diversity of the TILLING population. Approximately 28 polymorphic loci have been cloned and their sequences were BLAST-searched against rice whole genome sequences, resulting in 20 matches to each of the gene bodies including exon, intron, 1 kb upstream and 1 kb downstream regions. Six polymorphic loci evidenced changes in the coding regions of genes as compared to the rice pseudomolecules, 4 loci of which exhibited missense mutations and 2 loci of which exhibited silent mutations. Therefore, the results of our study show that the TILLING rice population should prove to be a useful genetic material pool for functional genomics as well as mutation breeding applications.