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        검색결과 91

        43.
        1991.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        외연적 유한요소법은 벡터처리에 적합한 구조를 가지고 있어 벡터컴퓨터를 이용하면 기존의 스칼라 컴퓨터에서보다 휠씬 빠르게 해석을 수행할 수 있다. 본 논문에서는 memory-to-memory방식의 벡터컴퓨터에서의 외연적 유한요소법의 효율적인 벡터화 방법을 제시하였다. 먼저 벡터컴퓨터의 구조적 특성과 무관하게 적용될 수 있는 일반적인 벡터화 기법을 고찰한 후 memory-to-memory방식의 벡터컴퓨터에 적합한 벡터화 기법을 개발하였다. 개발된 벡터화 기법의 유용성을 확인하기 위해 외연적 유한요소 프로그램인 DYNA3D를 memory-to-memory방식의 벡터컴퓨터인 HDS AS/XL V50에 이식한 결과 스칼라에 비해 2.4배 이상의 성능 향상을 얻을 수 있었다.
        4,600원
        44.
        1990.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        거대한 평판형 격자구조물올 연속체 평판으로 모델링하기 위한 보다 용이한 기법올 에너지동둥 개 념에 근기 하여 제시하였다. 단위 격 자가 갖 는 탄성변형에너지와 운동에너지를 구 할때 기폰의 유한요소 행렬을 이용하였다. 연속체 평 판의 퉁 가불성치 는 연속체평판과 격자평판에 해당하는 축소된 강성 및 질 량행 렬들 올 직 접 비 교 하여 구하였다- 본 연구에서 제안된 모 델링기법이 기존의 잘 알려진 기볍들에 옷지 않는 좋 은 결 과를 보여주고 있음을 예제해석을 통해 확인하였다.
        5,100원
        45.
        2017.12 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        With increased human activity in space, the risk of re-entry and collision between space objects is constantly increasing. Hence, the need for space situational awareness (SSA) programs has been acknowledged by many experienced space agencies. Optical and radar sensors, which enable the surveillance and tracking of space objects, are the most important technical components of SSA systems. In particular, combinations of radar systems and optical sensor networks play an outstanding role in SSA programs. At present, Korea operates the optical wide field patrol network (OWL-Net), the only optical system for tracking space objects. However, due to their dependence on weather conditions and observation time, it is not reasonable to use optical systems alone for SSA initiatives, as they have limited operational availability. Therefore, the strategies for developing radar systems should be considered for an efficient SSA system using currently available technology. The purpose of this paper is to analyze the performance of a radar system in detecting and tracking space objects. With the radar system investigated, the minimum sensitivity is defined as detection of a 1-m2 radar cross section (RCS) at an altitude of 2,000 km, with operating frequencies in the L, S, C, X or Ku-band. The results of power budget analysis showed that the maximum detection range of 2,000 km, which includes the low earth orbit (LEO) environment, can be achieved with a transmission power of 900 kW, transmit and receive antenna gains of 40 dB and 43 dB, respectively, a pulse width of 2 ms, and a signal processing gain of 13.3 dB, at a frequency of 1.3 GHz. We defined the key parameters of the radar following a performance analysis of the system. This research can thus provide guidelines for the conceptual design of radar systems for national SSA initiatives.
        46.
        2017.05 서비스 종료(열람 제한)
        Background : Korean mountain ginseng (Panax ginseng C.A. Meyer) are difficult to industrially apply because of its scarcity and high cost. Advances in plant biotechnology have made it possible to produce mountain ginseng on a large scale using adventitious root cultures in bio-reactors. This study was conducted to develop a cosmetic emulsion using ginsenoside and physiological activity - enhanced raw materials by fermentation process. Methods and Results : Wild ginseng adventitious roots were fermented with Pediococcus pentosaceus HLJG 0702 (KACC 81017BP). ginsenoside contents was analysed by using HPLC. Antioxidant activity was measured by DPPH and ABTS radical scavenging activity and whitening effect was measured by tyrosinase inhibitory activity. After microfluidizer processing was performed to prepare emulsions with homogenized particles, particle size and distribution were measured through a transmission electron microscop e(TEM). Particle stability compares pH, viscosity, light and zeta potential. When fermented with Pediococcus pentosaceus HLJG 0702, the highest change rates of Rg3, Rk1 and Rg5 were shown and the antioxidant activity was increased. The whitening effect was 73.2 ± 0.9% when treated at 100 ㎍/㎖, 1.5 times higher than the control. The optimum particle size and distribution were shown to be 418.0 ± 14.9 ㎚ for 6 times treatment with 0 - 10 times microfluidizer treatment. Stability was about 3% in pH, viscosity and light test. the zeta potential was found to be homogeneous at –33.33 mV. Conclusion : Pediococcus pentosaceus HLJG 0702 Fermented Wild ginseng adventitious roots were found to have effective ingredients and improved physiological activity. We have also developed emulsions that exhibit optimal particle size and distribution
        47.
        2016.12 KCI 등재 서비스 종료(열람 제한)
        The purpose of this study was to investigate the improvement of growth in Israeli carp (Cyprinus carpio), and the cross experiment was carried out with two strains of Israeli carp. Four combinations of Israeli carp from Jeonbuk fisheries farm and Songpu mirror carp from Heilong Jiang, China (KK; Jeonbuk ♀ × Jeonbuk ♂, KC; Jeonbuk ♀ × China ♂, CC; China ♀ × China ♂ and CK; China ♀ × Jeonbuk ♂) were developed and reared. Body length, body weight and condition factor were determined at 20, 40, 60 and 170 days post-hatch (DPH). The results showed that there were differences in growth rate of the four groups. Body length of four groups were CK > CC > KC > KK and body weight were CC > CK > KC > KK at 170 DPH. The growth perfomance of four groups were statistically significant difference (P<0.05). During the rearing, CC group had longer length and higher weight at 170 DPH compared to other three groups and also condition factor was highest in the CC group, but there was no significant difference in a survival rate. These results indicated that the growth performance mainly depended upon brooder combination but survival rate could not significantly affect brooder.
        48.
        2016.10 서비스 종료(열람 제한)
        Background : The minor saponins produced by the hydrolysis of a major saponins sugar. The minor saponins has high absorption and efficacy compared to major saponin. The acid treatment, heat treatment and fermentation with minor saponin research has been actively conducted. This study was performed in order to investigate the bioconversion of ginsenoside Rg5 of fermented wild ginseng adventitious roots by using lactic acid bacteria. Methods and Results : 20g adventitious roots of ginseng was added to water (10-fold v/w). 10% (v/v) of lactic acid bacteria (Pediococcus pentosaceus HLJG0702[KACC 81017BP]) were inoculated with wild ginseng adventitious roots. For the fermentation process the inoculated samples were transferred to culture room for 1, 3 and 5 days. The fermented samples were dried at room temperature and extracted with 70% ethanol. Extract was concentrated completely at 50 ℃ and Rg5 was analysed by using HPLC. Results showed no significant difference the dry weight of non-fermented and fermented wild ginseng adventitious roots. During the fermentation process, the pH changed from 5.7 to 4.2. HPLC analysis showed higher ginsenoside Rg5 (39.588 mg/g) at 3 days. Conclusion : The fermentation of ginseng root can increase the Rg5 contents and minor saponin composition. This process may be used to enhance the minor saponin thereby increasing in fermented property of wild ginseng adventitious roots.
        49.
        2016.10 서비스 종료(열람 제한)
        Background : This study, the fraction for testing the efficacy of the Astragalus extract was concentrated active ingredient. The concentrated fraction was applied to a cosmetic material that Astragalus testing results confirmed that the improved efficacy. Methods and Results : The fractions were performed using an n-butanol solvent for increasing the efficacy of the Astragalus extract, by using the material fractions collected to compare and ultimately an increase in whitening and wrinkle efficacy. The solvent to be used in the fractions was used for the n-butanol good dissolution to the effective substance(Astragaloside, Isoflavonoid). It increased approximately 6.5 times the sample extract and the n-butanol fraction of the Astragalus as a result Astragaloside 15 ppm, 97 ppm respectively analyzed by HPLC equipment, isoflavonoid content was confirmed by an increase in the content of the fractions increased 4.5 times to 280 ppm, 1,260 ppm. Tyrosinase inhibitory effect, respectively IC50 5.70 mg/mL, IC50 1.02 mg/mL to, Collagenase producing ability is IC50 4.88 mg/mL, IC50 0.93 mg/mL with n-butanol fraction was good whitening, anti-wrinkle efficacy than the extract. Sensory evaluation was conducted in the same amount of sample, using a purified Astragalus cosmetics received high marks. Stability evaluation(MTT assay) was checked for more than 100% cell viability at the concentration 2,000 ppm. Conclusion : n-butanol fraction of Astragalus was subjected to a component analysis and In vitro test, it was confirmed an increase active ingredient content. The results of sensory evaluation and stability evaluation, it was confirmed been made to improve qualities as a cosmetic materials.
        50.
        2015.12 KCI 등재 서비스 종료(열람 제한)
        Early life stage mortality in fish is one of the problems faced by loach aquaculture. However, our understanding of immune system in early life stage fish is still incomplete, and the information available is restricted to a few fish species. In the present work, we investigated the expression of immune-related transcripts in loach during early development. In fishes, recombination-activating gene 1 (RAG-1) and sacsin (SACS) have been considered as immunological function. In this study, the expression of the both genes was assessed throughout the early developmental stages of loach using real-time PCR method. maRAG-1 mRNA was first detected in 0 dph, observed the increased mostly until 40 dph. Significant expression of maRAG-1 was detected in 0 to 40 dph. These patterns of expression may suggest that the loach start to develop its function after hatching. On the other hand, maSACS was detected in unfertilized oocyte to molura stages and 0 to 40 dph. maSACS mRNA transcripts were detected in unfertilized oocytes, suggesting that they are maternally transferred.
        51.
        2014.07 서비스 종료(열람 제한)
        Mungbean (Vigna radiata) is a fast-growing, warm-season legume crop that is primarily cultivated in developing countries of Asia. We constructed a draft genome sequence of mungbean to facilitate genome research into the subgenus Ceratotropis and to enable a better understanding of the evolution of leguminous species. The draft genome sequence covers 80% of the estimated genome, of which 50.1% consists of repetitive sequences. In total, 22,427 high confidence protein-coding genes were predicted. Based on the de novo assembly of additional wild mungbean species, the divergence of what was eventually domesticated and the sampled wild mungbean species appears to have predated domestication. Moreover, the de novo assembly of a tetraploid Vigna species (Vigna reflexo-pilosa var. glabra) provided genomic evidence of a recent allopolyploid event. To further study speciation, we compared de novo RNA-seq assemblies of 22 accessions of 18 Vigna species and protein sets of Glycine max and Cajanus cajan. The species tree was constructed by a Bayesian Markov chain Monte Carlo method using highly confident orthologs shared by all 24 accessions. The present assembly of V. radiata var. radiata will facilitate genome research and accelerate molecular breeding of the subgenus Ceratotropis.
        52.
        2014.03 서비스 종료(열람 제한)
        Marked neutrophilia associated with neoplasia is a relatively rare finding and has been considered as a paraneoplastic manifestation. Thyroid cancer seldom presents with paraneoplastic leukocytosis. We report on a case of a 69-year-old man who presented with paraneoplastic leukocytosis seven months after undergoing total thyroidectomy and I-131 therapy for treatment of papillary thyroidcarcinoma. We found neither bone marrow involvement of malignant cells nor hematologic malignancy. Based on elevated levels of serum granulocyte colony-stimulating factor, we concluded that the cause was paraneoplastic leukocytosis. Another interesting point was the anaplastic transformation in the pleural metastatic site. It usually occurs in the intrathyroid or regional lymph node.
        53.
        2013.09 KCI 등재 서비스 종료(열람 제한)
        Olive flounder (Paralichthys olivaceus) is one of the commercial important flatfish species in Korea. The ocular signal transduction pathway is important in newly hatched flounders because it is closely involved in the initial feeding phase thus essential for survival during the juvenile period. However, the study of gene expression during ocular development is incomplete in olive flounder. Therefore we examined the expression analysis of specifically induced genes during the development of the visual system in newly hatched flounders. We searched ocular development-involved gene in the database of expressed sequence tags (ESTs) from olive flounder eye and this gene similar to arrestin with a partial sequence homology. Microscopic observation of retinal formation corresponded with the time of expression of the arrestin gene in the developmental stage. These results suggest that arrestin plays a vital role in the visual signal transduction pathway of the retina during ocular development. The expression of arrestin was strong in the ocular system during the entirety of the development stages. Our findings regarding arrestin have important implications with respect to its biological role and evolution of G-protein coupled receptor (GPCR) signaling in olive flounder. Further studies are required on the GPCR-mediated signaling pathway and to decipher the functional role of arrestin.
        54.
        2013.07 서비스 종료(열람 제한)
        Low temperature is a major factor restrict to growth and limiting productivity of rice crops. We used a cDNA microarray approach to monitor the expression profile of rice (Oryza sativa) under chilling stress and identified 20 chilling inducible genes in previously study. Ten such genes encoding bHLH, metal transporter and, zinc finger protein with unknown functions showed a significant change in expression under various abiotic stresses. Among them, OsCHI1 (Os07g15460), OsCHI2 (Os02g43660), and OsCHI3 (Os01g61160), were selected for further study. They have structural features such as metal-binding signature sequences in their protein sequences, and OsCHI genes were expressed in root of rice seedling and induced in chilling and salt or drought. Expression of OsCHI1, OsCHI3 and OsCHI2 were targeted to membrane and ER when transiently expressed in tobacco cell, respectively. The Arabidopsis (Arabidopsis thaliana) transgenic plants overexpressing showed increased tolerance to salt and drought stress in the seed germination and root elongation than that of wild type. This comprehensive study provides insight into the biological function of OsCHIs, which may be useful in understanding how rice plants adapt to unfavorable environmental conditions.
        55.
        2013.07 서비스 종료(열람 제한)
        Arabidopsis atDjC53 and atDjC32 gene DnaJ-like protein homologous to DnaJ-like protein was characterized for the functional analysis of DnaJ-like protein. It was shown that atDjC53 and atDjC32 RNA expression is induced by heat shock stress and atDjC53- and atDjC32-GFP was targeted to the nucleus of protoplasts. The atDjC53 and atDjC32 promoter (1 kb) was isolated and fused to the GUS reporter gene to investigate gene regulation of atDjC53 and atDjC32 specific to heat shock stress or to developmental organ in the transgenic lines. RNAi and overexpression construct was employed to generate atDjC53 and atDjC32 knock-out plants for the study of their function. Molecular function of atDjC53 and atDjC32 is discussed in relation to heat shock and also developmental stages in Arabidopsis.
        56.
        2013.07 서비스 종료(열람 제한)
        Heat shock transcription factors (HSFs) are the major heat shock factors regulating the heat stress response. They participate in regulating the expression of heat shock proteins (HSPs), which are critical in the protection against stress damage and many other important biological processes. In this study, a genome-wide analysis was carried out to identify all HSFs soybean genes. Twenty six nonredundant HSF genes (GmHsf) were identified in the latest soybean genome sequence. Chromosomal location, protein domain and motif organization of GmHsfs were analyzed in soybean genome. The phylogenetic relationships, gene duplications and expression profiles of GmHsf genes were also presented in this study. According to their structural features, the predicted members were divided into the previously defined classes A–C, as described in Arabidopsis. Using RT-PCR, the expression patterns of 26 GmHsf genes were investigated under heat stress. The data revealed that these genes presented different expression levels in response to heat stress conditions. Real-time (q)RT-PCR was performed to investigate transcript levels of five GmHsfs in response to multiple abiotic stresses. Differential expression of five GmHsfs implies their role during abiotic stresses. Subcellular localization using GFP-fusion protein demonstrated that GmHsf12 and GmHsf34 were restricted to the nucleus and GmHsf28 was localized in the nucleus and cytoplasm in plant. The results provide a fundamental clue for understanding of the complexity of the soybean HSF gene family and cloning specific function genes in further studies and applications.
        57.
        2013.07 서비스 종료(열람 제한)
        Salinity stress severely affects plant growth and development causing crop loss worldwide. Suaeda asparagoides is a salt-marsh euhalophyte widely distributed in southwestern foreshore of Korea. To isolate salt tolerance genes from S. asparagoides, we constructed a cDNA library from leaf tissues of S. asparagoides that was treated with 200 mM NaCl. A total of 1,056 clones were randomly selected for EST sequencing, and 932 of them produced readable sequence. By sequence analysis, we identified 538 unigenes and registered each in National Center for Biotechnology Information. The 80 salt stress related genes were selected to study their differential expression. Reverse Transcriptase-PCR and Northern blot analysis revealed that 23 genes were differentially expressed under the high salinity stress conditions in S. asparagoides. They are functionally diverse including transport, signal transduction, transcription factor, metabolism and stress associated protein, and unknown function. Among them dehydrin (SaDhn) and RNA binding protein (SaRBP1) were examined for their abiotic stress tolerance in yeast (Saccharomyces cerevisiae). Yeast overexpressing SaDhn and SaRBP1 showed enhanced tolerance to osmotic, freezing and heat shock stresses. This study provides the evidence that SaRBP1 and SaDhn from S.asparagoides exert abiotic stress tolerance in yeast. Information of salt stress related genes from S. asparagoides will contribute for the accumulating genetic resources to improve osmotic tolerance in plants.
        58.
        2013.07 서비스 종료(열람 제한)
        The ubiquitin conjugating enzyme E2 (UBC E2) mediates selective ubiquitination, acting with E1 and E3 enzymes to designate specific proteins for subsequent degradation. In the present study, we characterized the function of the mung bean VrUBC1 gene (Vigna radiata UBC 1). RNA gel-blot analysis showed that VrUBC1 mRNA expression was induced by either dehydration, high salinity or by the exogenous abscisic acid (ABA), but not by low temperature or wounding. Biochemical studies of VrUBC1 recombinant protein and complementation of yeast ubc4/5 by VrUBC1 revealed that VrUBC1 encodes a functional UBC E2. To understand the function of this gene in development and plant responses to osmotic stresses, we overexpressed VrUBC1 in Arabidopsis (Arabidopsis thaliana). The VrUBC1-overexpressing plants displayed highly sensitive responses to ABA and osmotic stress during germination, enhanced ABA- or salt-induced stomatal closing, and increased drought stress tolerance. The expression levels of a number of key ABA signaling genes were increased in VrUBC1-overexpressing plants compared to the wild-type plants. Yeast two-hybrid and bimolecular fluorescence complementation demonstrated that VrUBC1 interacts with AtVBP1 (A. thaliana VrUBC1 Binding Partner 1), a C3HC4-type RING E3 ligase. Overall, these results demonstrate that VrUBC1 plays a positive role in osmotic stress tolerance through transcriptional regulation of ABA-related genes and possibly through interaction with a novel RING E3 ligase.
        59.
        2013.03 서비스 종료(열람 제한)
        Acinetobacter baumannii is usually considered an opportunistic pathogen that it responsible for a variety of nosocomial infections, such as, pneumonia, tracheobronchitis, meningitis, endocarditis, peritonitis, skin and soft tissue infections, and urinary tract infections. However, over the years, the organism has developed substantial antimicrobial resistance, and thus, the management of infections has become more difficult. The less common infective endocarditis is one of the more serious consequences of nosocomial bacteremia. Here, we report the successful treatment of the first case of multidrug-resistant A. baumannii endocarditis in a 33-year-old patient.
        60.
        2012.07 서비스 종료(열람 제한)
        R genes are a key component of genetic interactions between plants and biotrophic bacteria and are known to regulate resistance against bacterial invasion. The most common R proteins contain a nucleotide-binding site and a leucine-rich repeat (NBS-LRR) domain. Some soybean NBS-LRR genes have also been reported to function in disease resistance. A total of 319 genes were determined to be putative NBS-LRR genes in the soybean genome. The number of NBS-LRR genes on each chromosome was highly correlated with the number of disease resistance QTL in the 2-Mb flanking regions of NBS-LRR genes. In addition, the recently duplicated regions contained duplicated NBS-LRR genes and duplicated disease resistance QTL, and possessed either an uneven or even number of NBS-LRR genes on each side. The significant difference in NBS-LRR gene expression between a resistant near-isogenic line (NIL) and a susceptible NIL after inoculation of Xanthomonas axonopodis pv. glycines supports the conjecture that NBS-LRR genes have disease resistance functions in the soybean genome. The number of NBS-LRR genes and disease resistance QTL in the 2-Mb flanking regions of each chromosome was significantly correlated, and several recently duplicated regions that contain NBS-LRR genes harbored disease resistance QTL for both sides. In addition, NBS-LRR gene expression was significantly different between the BLP-resistant NIL and the BLP-susceptible NIL in response to bacterial infection. From these observations, NBS-LRR genes are suggested to contribute to disease resistance in soybean. Moreover, we propose models for how NBS-LRR genes were duplicated, and apply Ks values for each NBS-LRR gene cluster.
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