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        검색결과 781

        561.
        2015.09 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        We estimated the orbit of the Communication, Ocean and Meteorological Satellite (COMS), a Geostationary Earth Orbit (GEO) satellite, through data from actual optical observations using telescopes at the Sobaeksan Optical Astronomy Observatory (SOAO) of the Korea Astronomy and Space Science Institute (KASI), Optical Wide field Patrol (OWL) at KASI, and the Chungbuk National University Observatory (CNUO) from August 1, 2014, to January 13, 2015. The astrometric data of the satellite were extracted from the World Coordinate System (WCS) in the obtained images, and geometrically distorted errors were corrected. To handle the optically observed data, corrections were made for the observation time, light-travel time delay, shutter speed delay, and aberration. For final product, the sequential filter within the Orbit Determination Tool Kit (ODTK) was used for orbit estimation based on the results of optical observation. In addition, a comparative analysis was conducted between the precise orbit from the ephemeris of the COMS maintained by the satellite operator and the results of orbit estimation using optical observation. The orbits estimated in simulation agree with those estimated with actual optical observation data. The error in the results using optical observation data decreased with increasing number of observatories. Our results are useful for optimizing observation data for orbit estimation.
        562.
        2015.09 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        To protect and manage the Korean space assets including satellites, it is important to have precise positions and orbit information of each space objects. While Korea currently lacks optical observatories dedicated to satellite tracking, the Korea Astronomy and Space Science Institute (KASI) is planning to establish an optical observatory for the active generation of space information. However, due to geopolitical reasons, it is difficult to acquire an adequately sufficient number of optical satellite observatories in Korea. Against this backdrop, this study examined the possible locations for such observatories, and performed simulations to determine the differences in precision of optical orbit estimation results in relation to the relative baseline distance between observatories. To simulate more realistic conditions of optical observation, white noise was introduced to generate observation data, which was then used to investigate the effects of baseline distance between optical observatories and the simulated white noise. We generated the optical observations with white noise to simulate the actual observation, estimated the orbits with several combinations of observation data from the observatories of various baseline differences, and compared the estimated orbits to check the improvement of precision. As a result, the effect of the baseline distance in combined optical GEO satellite observation is obvious but small compared to the observation resolution limit of optical GEO observation.
        563.
        2015.09 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        An algorithm to automatically extract coordinate and time information from optical observation data of geostationary orbit satellites (GEO satellites) or geosynchronous orbit satellites (GOS satellites) is developed. The optical wide-field patrol system is capable of automatic observation using a pre-arranged schedule. Therefore, if this type of automatic analysis algorithm is available, daily unmanned monitoring of GEO satellites can be possible. For data acquisition for development, the COMS1 satellite was observed with 1-s exposure time and 1-m interval. The images were grouped and processed in terms of “action”, and each action was composed of six or nine successive images. First, a reference image with the best quality in one action was selected. Next, the rest of the images in the action were geometrically transformed to fit in the horizontal coordinate system (expressed in azimuthal angle and elevation) of the reference image. Then, these images were median-combined to retain only the possible non-moving GEO candidates. By reverting the coordinate transformation of the positions of these GEO satellite candidates, the final coordinates could be calculated.
        564.
        2015.07 서비스 종료(열람 제한)
        MicroRNAs (miRNAs) are a class of non-coding RNAs approximately 21-nt in length which play important roles in regulating gene expression in plants. Although many miRNA studies have focused on a few model plants, miRNAs and their target genes remain largely unknown in hot pepper (Capsicum annuum), one of the most important crops cultivated worldwide. We here employed high-throughput small-RNA and degradome sequencing to comprehensively identify small-RNAs and their targets in pepper. From these, we identified several novel targets of miRNAs, including the major de novo methylation enzyme involved in RNA-directed DNA methylation in plants. Furthermore, we identified several highly abundant 22-nt miRNA families that target conserved domains in NB-LRRs and trigger the production of phased secondary siRNAs. We showed that transient co-expression of can-miR482 with Rpi-blb1, one of the potato NB-LRRs, resulted in the attenuation of the hypersenstive responses in Nicotiana benthamiana, suggesting that interaction between miR-482 family and disease resistance proteins is likely to serve as a conserved trigger for defense mechanism in Solanaceae. This work provides the first reliable draft of the pepper small RNA transcriptome that offers an expanded picture of miRNAs in relation to NB-LRR regulation, providing a basis for understanding the functional roles of miRNAs in disease resistance pepper.
        565.
        2015.07 서비스 종료(열람 제한)
        High yield is the most important trait in various agricultural characteristics. Many approaches to improve yield have been tried in conventional agricultural practice and recently biotechnological tools employed for same goal. Genetic transformation of key genes to increase yield is one way to overcome current limitation in the field. We are producing transgenic soybean plants through high efficient transformation method by introducing all gene member with AT-hook binding domain, hoping to obtain manageable delay of senescence. Many transgenic soybean plants are growing in greenhouse and GMO field, and will be evaluated their senescence and any association with yield increase.
        566.
        2015.07 서비스 종료(열람 제한)
        To understand molecular mechanisms underlying adaptation of plant cells to saline stress and stress memory, we developed Arabidopsis callus suspension-cultured cells adapted to high salt. Adapted cells to high salt exhibited enhanced tolerance compared to control cells. Moreover, the salt tolerance of adapted cells was stably maintained even after the stress is relieved, indicating that the salt tolerance of adapted cells was memorized. Salt-adapted and stress memorized cells were densely aggregated and formed multi-layered cell lump. Cell morphology analysis using transmission electron microscopy indicated that cell wall thickness of salt-adapted cells was significantly induced compared to control cells. In order to characterize metabolic responses of plant cells during adaptation to high salt stress as well as stress memory, we compared metabolic profiles of salt-adapted and stress-memorized cells with control cells by using NMR spectroscopy. A principle component analysis showed clear metabolic discrimination among control, salt-adapted and stress-memorized cells. Compared with control cells, metabolites related to shikimate metabolism such as tyrosine, and flavonol glycosides, which are related to protective mechanism of plant against stresses were largely up-regulated in adapted cell lines. Moreover, coniferin, a precursor of lignin, was more abundant in salt-adapted cells than control cells. The results provide new insight into metabolic level mechanisms of plant adaptation to saline stress as well as stress memory.
        567.
        2015.07 서비스 종료(열람 제한)
        To identify novel signaling components involved in regulation of plant responses to phosphate (Pi) starvation, we screened an Arabidopsis T-DNA activation tagging library for mutants with altered Pi-starvation responses. Here, we report the identification and characterization of novel activation-tagged mutant involved in Pi starvation signaling in Arabidopsis. The hpd (hypersensitive to Pi deficiency) mutant exhibits enhanced phosphate uptake and altered root architectural change under Pi starvation compared to wild type. Expression analysis of auxin-responsive DR5::GUS reporter gene in hpd mutant indicated that both auxin biosynthesis and auxin translocation under Pi starvation are suppressed in hpd mutant plants. Impaired auxin translocation in roots of hpd mutant was attributable to abnormal root architecture changes in Pi starvation conditions. Mis-regulation of auxin translocation in hpd mutant was further confirmed by analysis of expression patterns of auxin efflux carrier proteins, PIN-FORMED (PIN) 1, 2, and 3 fused with GFP. Not only expression levels but also expression domains of PIN proteins were altered in hpd mutant in response to Pi starvation. Molecular genetic analysis of hpd mutant revealed that the mutant phenotype is caused by the lesion in ENHANCED SILENCING PHENOTYPE4 (ESP4) gene whose function is proposed in mRNA 3’-end processing. The results propose that mRNA processing plays crucial roles in Pi homeostasis as well as developmental reprograming in response to Pi deprivation in Arabidopsis.
        568.
        2015.07 서비스 종료(열람 제한)
        Soybean (Glycine max (L.) Merr) is a short day plant and has been adapted to various climates and environments during cultivation. However, the cultivation area is restricted to a very narrow range of latitudes. To date, nine major genes (E1 to E8 and J) have been reported to control the flowering time and maturity. Here, we evaluated the role of E2, E3, E4, and their paralogue genes in late flowering soybean cultivars under long day (LD) conditions using Soybean yellow common mosaic virus (SYCMV)-based virus-induced gene silencing (VIGS) system. A total of nine VIGS constructs were infiltrated into two fully expanded cotyledons and primary leaves. After inoculation with these VIGS constructs on Jangyeobkong, which is a late-flowering cultivar, phenotypic traits were evaluated for the first flowering dates (FFDs) and pod maturities under LD conditions. The FFDs of the silenced plants occurred 50-56 days after sowing (das), while the non-silenced plants bloomed on 60-61 days. We found that the E3 paralogue-silenced plants flowered the fastest and responsive genes were identified to be associated with the promotion of flowering time. As the knock-down of E3 paralogue, expression of E1 was up-regulated, E2 was no difference, E3 and E4 genes were down-regulated in the silenced plants. Expression of GmFT2a and GmFT5a is known to be controlled by E3 and E4. Interestingly, GmFT5a were highly expressed in SYCMV:E3 paralogue-silenced plants, whereas the expression of GmFT2a was not significant. These results support that GmFT5a is able to independently promote flowering under LD conditions.
        569.
        2015.07 서비스 종료(열람 제한)
        Poor germination and labor intensive thinning of seedling after sowing are major deterrents in Setaria viridis production. Seed priming has the potential to improve the seedling emergence and economic feasibility by combined with seed coating for optimizing mechanized growing technologies to small cereal crops. The objective of this study was to determine the effective seed priming conditions on the improved germination in the laboratory. Seeds were hydro primed with distilled water for 6, 12, 24 hours and osmoprimed with PEG8000 (-0.15 MPa and -0.3 MPa), KCl (1% and 2%), KH2PO4 (0.5% and 1.0%), KNO3(1.0% and 3.0%), CaCl2 (1.0% and 3.0%) solutions for 6, 12, 24 hours at 15℃. Our results demonstrate that treating S. viridis seeds with PEG -0.3 MPa solution for 12h increased to maximum germination percentage to 97%, whereas the lowest germination percentage observed in seeds which treated with by CaCl2 1.0% for 24h and KCl 1% for 6h. Priming reduced the mean germination times (MGT) of all priming treated seeds statistically comparing to control. There was significant interaction between treatment and time. Further studies for field performance of primed seeds are needed.
        570.
        2015.07 서비스 종료(열람 제한)
        This study was conducted to affirm the potential of seed priming techniques for optimizing mechanized growing technologies to maintain production of sustainable small cereal crops. Seed priming conditions were preliminary tested in laboratory. Sorghum seeds were hydroprimed and osmoprimed comprising a total of 33 treatments of different priming combination along with control. Seed primed in aerated solution of distilled water, PEG8000 (-0.15 MPa and –0.3 MPa), KCl(1% and 2%), KH2PO4 (0.5% and 1.0%), KNO3 (1.0% and 3.0%), CaCl2 (1.0% and 3.0%) solutions for 6, 12, 24 hours at 15℃. Maximum seed germination percentage, germination rate and reduced mean germination times (MGT) were observed when the seeds primed by CaCl2 1.0% for 24 h, whereas the lowest germination percentage observed in seeds which treated with KNO3 3% solution. Priming improved the MGT, germination index, and germination rate of all primed seeds statistically comparing to control. The MGT reduced by increase of treatment time. Further studies for field performance of primed seeds are needed.
        571.
        2015.07 서비스 종료(열람 제한)
        This study was conducted to affirm the potential of seed priming techniques for optimizing mechanized growing technologies to maintain production of sustainable small cereal crops. Seed priming conditions were preliminary tested in laboratory. Sorghum seeds were hydroprimed and osmoprimed comprising a total of 33 treatments of different priming combination along with control. Seed primed in aerated solution of distilled water, PEG8000 (-0.15 MPa and –0.3 MPa), KCl(1% and 2%), KH2PO4 (0.5% and 1.0%), KNO3 (1.0% and 3.0%), CaCl2 (1.0% and 3.0%) solutions for 6, 12, 24 hours at 15℃. Maximum seed germination percentage, germination rate and reduced mean germination times (MGT) were observed when the seeds primed by CaCl2 1.0% for 24 h, whereas the lowest germination percentage observed in seeds which treated with KNO3 3% solution. Priming improved the MGT, germination index, and germination rate of all primed seeds statistically comparing to control. The MGT reduced by increase of treatment time. Further studies for field performance of primed seeds are needed.
        572.
        2015.07 서비스 종료(열람 제한)
        MicroRNAs (miRNAs) are a class of non-coding RNAs approximately 21-nt in length which play important roles in regulating gene expression in plants. Although many miRNA studies have focused on a few model plants, miRNAs and their target genes remain largely unknown in hot pepper (Capsicum annuum), one of the most important crops cultivated worldwide. We here employed high-throughput sequencing to comprehensively identify small RNAs and their targets in pepper. From these, we identified several novel targets of miRNAs, including the major de novo methylation enzyme involved in RNA-directed DNA methylation in plants. Furthermore, we identified several highly abundant 22-nt miRNA families that target conserved domains in NB-LRRs. We showed that transient co-expression of the miRNA with NB-LRRs, resulted in the attenuation of the hypersenstive responses in Nicotiana benthamiana, suggesting that interaction between miRNA family and disease resistance proteins is likely to serve as a conserved trigger for defense mechanism in Solanaceae. This work provides the first reliable draft of the small RNA transcriptome in pepper that offers an expanded picture of miRNAs in relation to NB-LRR regulation, providing a basis for understanding the functional roles of miRNAs in disease resistance.
        573.
        2015.06 서비스 종료(열람 제한)
        Diffuse involvement of the right pulmonary artery (PA) associated with fistula between the PA and coronary artery is report-ed in a woman with Takayasu’s arteritis. Both the subclavian arteries were totally occluded and drained by the meanderinged artery arising from both common carotid arteries. Lung perfusion scan revealed perfusion defect of right lung. Two fistulas were identified. A large fistula was between the right PA and left circumflex artery. A small fistula was between the right PA and left anterior descending artery. This is a rare case of Takayasu’s arteritis presenting with a coronary – pulmonary artery fistula that is secondary to a diffuse unilateral involvement of PA.
        574.
        2015.03 KCI 등재 서비스 종료(열람 제한)
        This study investigated possible involvement of photoperiodic regulation in reproductive endocrine system of female olive flounder. To investigate the influence on brain-pituitary axis in endocrine system by regulating photoperiod, compared expression level of Kisspeptin and sbGnRH mRNA in brain and FSH-β, LH-β and GH mRNA in pituitary before and after spawning. Photoperiod was treated natural photoperiod and long photoperiod (15L:9D) conditions from Aug. 2013 to Jun. 2014. Continuous long photoperiod treatment from Aug. (post-spawning phase) was inhibited gonadal development of female olive flounder. In natural photoperiod group, the Kiss2 expression level a significant declined in Mar. (spawning period). And also, FSH-β, LH-β and GH mRNA expression levels were increasing at this period. However, in long photoperiod group, hypothalamic Kiss2, FSH-β, LH-β and GH mRNA expression levels did not show any significant fluctuation. These results suggest that expression of hypothalamic Kiss2, GtH and GH in the pituitary would change in response to photoperiod and their possible involvement of photoperiodic regulation in reproductive endocrine system of the BPG axis.
        575.
        2014.12 서비스 종료(열람 제한)
        Primary progressive aphasia (PPA) is a progressive degenerative disorder that primarily affects language. Although the etiology of PPA has not been determined, autoimmune mechanism is known to be one possible pathophysiology. We investigate efficacy of steroid treatment in a patient diagnosed as both logopenic variant PPA and Sjögren's syndrome. After steroid treatment, her cognitive function, especially language ability showed improvement. And also, FDG-PET showed metabolic increase in the bilateral temporal lobe. However, on reassessment after stopping steroid treatment, her cognitive performance declined to pretreatment level.
        577.
        2014.09 서비스 종료(열람 제한)
        The isolated single coronary artery is a rare congenital anomaly, in which both coronary arteries arise from a solitary ostium. Diagnosis of coronary anomalies and identification of the exact anatomy of coronary arteries has significant clinical importance, hence, myocardial ischemia or sudden cardiac death is usually related to its course of anomalous coronary artery. Most patients with a single coronary artery are asymptomatic and have normal electrocardiogram and negative stress tests. However, if the patient has other structural abnormalities, for example, ventricular hypertrophy, the exam is determined. This report describes a case of single coronary artery, where the right coronary artery originated from the distal left circumflex artery in a patient with hypertrophic ardiomyopathy.
        578.
        2014.09 서비스 종료(열람 제한)
        We determined intravitreal levels of vascular endothelial growth factor (VEGF) and pigment epithelium derived factor (PEDF) in patients with early phase rhegmatogenous retinal detachment (RRD). Twenty five eyes of 25 RRD patients with symptom onset from one day to 21 days prior to vitrectomy were selected. Concentrations of VEGF and PEDF in vitreous were determined by enzyme-linked immunosorbent assay and relationships between these concentrations and durations and involved quadrants were analyzed. Duration of RRD was found to show significant correlation with PEDF concentration. However, number of involved quadrants did not show correlation with PEDF concentration in vitreous.
        579.
        2014.09 서비스 종료(열람 제한)
        The transcription factor, early growth response protein 1 (EGR1), act as immediate early response genes to control various cellular and reproductive events. Egr1-deficient female mice show infertility by anovulation resulting from luteinizing hormone-β (LH-β) subunit deficiency. While ovulation, fertilization and embryo development normally occur in Egr1-deficient mice treated with a superovulation regime to rescue LH deficiency, embryo implantation was completely failed. The morphology and ultrastructure of uterine tissues were observed by light and transmission electron microscopy during the peri-implantation period in Egr1-deficient mice. To examine alterations in cellular organelles, the uterine horns were fixed with 2.5% glutaraldehyde and postfixed with 1% osmium tetroxide in PBS. After dehydration and infiltration, the samples were embedded in Epon 812. Semi-thin sections 0.5 μm thick were cut with an ultramicrotome and stained with toluidine blue for light microscopy. Thin sections were cut with a diamond knife of the ultramicrotome and placed on copper grids. The sections were double stained and examined under a transmission electron microscope. The height of luminal epithelial cells was decreased and the polarity was poorly differentiated in the Egr1-deficient comparing to the wild mice. The abundant mucinous materials were observed in the surface of luminal epithelial cells of the Egr1-deficient. It was confirmed the microarray and real time qPCR data. The luminal epithelial cells of wild mice had many dense lipophilic granules and healthy mitochondria, but not in the Egr1-deficient. It may related to production and secretion of steroid hormones and prostaglandins in the luminal epithelial cells for successful implantation. These results show that Egr1 is a critical transcription factor to fine-tune subcellular morphological and functional changes for the receptive phase of peri-implantation period of uterine tissue in mice.
        580.
        2014.09 서비스 종료(열람 제한)
        The aim of this study was to analyze the effect of antifreeze proteins (AFPs) on vitrification of mouse mature (MII) oocytes. We studied about 3 types of AFPs from different origins (FfIBP, LeIBPand Type III AFP). The MII oocytes were obtained from 4-week-old BD-F1 mice. Vitrification of oocyte was performed by 2 steps using the Cryotop (equilibration: 7.5% EG + 7.5% PROH for 5 min, vitrification: 15% EG + 15% PROH + 0.5M sucrose for 1 min). The concentrations of AFPs added to these solutions were 0.05 mg/ml for FfIBP and 0.1 mg/ml for LeIBP and Type III AFP. After fertilization, embryo development was assessed up to 5 days. Through immunostaining of vitrified-warmed oocytes, we assessed the normal meiotic spindle. Also, intracellular ROS and mitochondrial activity was analyzed. In the developmental stages, FfIBP and LeIBP groups showed significantly higher survival rates. In the blastocyst and apoptotic blastomere rates were significant differences in AFPs treated groups. AFPs treated groups were significantly higher in blastocyst cell numbers than control group. Among the AFPs treated groups, FfIBP, LeIBP groups were significantly higher rates. And, in cleavage rates, FfIBP group was significantly higher rates than the other groups. In vitrified-warmed MII oocytes, the normal meiotic spindle organization and chromosome alignment rate was significantly higher in FfIBP and LeIBP groups. And in intracellular ROS levels, control group was significantly increased than AFPs treated groups. However, in the mitochondrial activity, LeIBP group was significantly higher than control, FfIBP and LeIBP groups. AFPs treated groups were significant differences in development, meiotic spindle organization and intracellular ROS levels. And in the AFPs treated groups, FfIBP and LeIBP groups were significantly higher rates in normal meiotic spindle and mitochondrial activity than Type III AFP group respectively. In conclusion, FfIBP and LeIBP can be thought to improve oocyte cryopreservation efficiency.