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        검색결과 19

        1.
        2022.10 구독 인증기관·개인회원 무료
        The safe, efficient and cost-effective decommissioning and dismantling of radioactive facilities requires the accurate characterization of the radionuclide activities and dose rate environment. And it is critical across many nuclear industries to identify and locate sources of radiation accurately and quickly. One of the more challenging aspects of dealing with radiation is that you cannot see it directly, which can result in potential exposure when working in those environments. Generally, semiconductor detectors have better energy resolution than scintillation detectors, but the maximum achievable count rates are limited by long pulse signals. Whereas some high pure germanium detectors have been developed to operate at high count rates, and these HPGe detectors could obtain gamma-ray spectra at high count rates exceeding 1 Mcps. However, HPGe detectors require cooling devices to reduce the leak currents, which becomes disadvantageous when developing portable radiation detectors. Furthermore, chemicalcompound semiconductor detectors made of cadmium telluride and cadmium zinc telluride are popular, because they have good energy resolution and are available at room temperature. However, CdTe and CZT detectors develop irradiation-induced defects under intense gamma-ray fields. In this Review, we start with the fundamentals of gamma rays detection and review the recent developments in scintillators gamma-ray detectors. The key factors affecting the detector performance are summarized. We also give an outlook on the field, with emphasis on the challenges to be overcome.
        3.
        2021.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Climate change effects are particularly apparent in many cool-season grasslands in South Korea. Moreover, the probability of climate extremes has intensified and is expected to increase further. In this study, we performed climate change vulnerability assessments in cool-season grasslands based on the analytic hierarchy process method to contribute toward effective decision-making to help reduce grassland damage caused by climate change and extreme weather conditions. In the analytic hierarchy process analysis, vulnerability was found to be influenced in the order of climate exposure (0.575), adaptive capacity (0.283), and sensitivity (0.141). The climate exposure rating value was low in Jeju-do Province and high in Daegu (0.36–0.39) and Incheon (0.33–0.5). The adaptive capacity index showed that grassland compatibility (0.616) is more important than other indicators. The adaptation index of Jeollanam-do Province was higher than that of other regions and relatively low in Gangwon-do Province. In terms of sensitivity, grassland area and unused grassland area were found to affect sensitivity the most with index values of 0.487 and 0.513, respectively. The grassland area rating value was low in Jeju-do and Gangwon-do Province, which had large grassland areas. In terms of vulnerability, that of Jeju-do Province was lower and of Gyeongsangbuk-do Province higher than of other regions. These results suggest that integrating the three aspects of vulnerability (climate exposure, sensitivity, and adaptive capacity) may offer comprehensive and spatially explicit adaptation plans to reduce the impacts of climate change on the cool-season grasslands of South Korea.
        4,000원
        4.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We demonstrated an effective way of preparing melt spinnable mesophase pitches via catalytic hydrogenation of petroleum residue (fluidized catalytic cracking-decant oil) and their subsequent thermal soaking. The mesophase pitches thus obtained were analyzed in terms of their viscosity, elemental composition, solubility, molecular weight, softening point and optical texture. We found that zeolite-induced catalytic hydrogenation under high hydrogen pressure contributed to a large variation in the properties of the pitches. As the hydrogen pressure increased, the C/H ratio decreased, and the solubility in n-hexane increased. The mesophase pitch with entirely anisotropic domains of flow texture exhibited good meltspinnability. The mesophase carbon fibers obtained from the catalytically hydrogenated petroleum residue showed moderate mechanical properties.
        4,000원
        5.
        2013.10 구독 인증기관·개인회원 무료
        Peptidoglycan recognition proteins (PGRPs) are family of innate immune molecules that recognize bacterial peptidoglycan. PGRP-LE, a member of the PGRP family, selectively binds to diaminopimelic acid (DAP)-type peptidoglycan to activate both the immune deficiency (IMD) and proPhenoloxidase (proPO) pathways in insects. A PGRP-LE-dependent induction of autophagy to control Listeria monocytogenes has also been reported. We identified and partially characterized a novel PGRP-LE homologue, from Tenebrio molitor and analyzed its functional role in the survival of the insect against infection by a DAP-type PGN containing intracellular pathogen, L. monocytogenes. The cDNA is comprised of an open reading frame (ORF) of 990 bp and encodes a polypeptide of 329 residues. TmPGRP-LE contains one PGRP domain, but lacks critical residues for amidase activity. Quantitative RT-PCR analysis showed a broad constitutive expression of the transcript at various stages of development spanning from larva to adult. RNAi mediated knockdown of the transcripts followed by a challenge with L. monocytogenes showed a significant reduction in survival rate of the larvae, suggesting a putative role of TmPGRP-LE in sensing and control of L. monocytogenes infections in T. molitor. These results implicate PGRP-LE as a defense protein necessary for survival of T. molitor against infection by L. monocytogenes.
        6.
        2013.10 구독 인증기관·개인회원 무료
        CD63, a member of tetraspanin membrane protein family, plays pivotal role in cell growth, motility, signal transduction, host-pathogen interactions and cancer. In this work, the cDNA encoding CD63 homologue (TmCD63) was cloned from larvae of coleopteran beetle, Tenebrio molitor. The cDNA is comprised of an open reading frame of 705 bp, encoding putative protein of 235 amino acid residues. In silico analysis shows that the protein has four putative transmembrane domains and one large extracellular loop. The characteristic ‘Cys-Cys-Gly’ motif and ‘Cys188’ residues are highly conserved in the large extracellular loop. Phylogenetic analysis of TmCD63 revealed that they belong to the insect cluster with 50-56% identity. Analysis of spatial expression patterns demonstrated that TmCD63 mRNA is mainly expressed in gut and Malphigian tubules of larvae and the testis of the adult. Developmental expression patterns of CD63 mRNA showed that TmCD63 transcripts are detected in late larval, pupal and adult stages. Interestingly, TmCD63 transcript was upregulated the maximum 4.5 fold in response to DAP-type peptidoglycan during the first 6 h, although other immune elicitors also made significant increase in the transcript level at later time-points. These results suggest that CD63 might contribute to T. molitor immune response against various microbial pathogens.
        7.
        2013.10 구독 인증기관·개인회원 무료
        Apolipophorin III (apoLp-III) is a well-known hemolymph protein having a functional role in lipid transport and immune response of insects. We cloned full-length cDNA encoding putative apoLp-III from larvae of the coleopteran beetle, Tenebrio molitor (TmapoLp-III), by identification of clones corresponding to the partial sequence of TmapoLp-III, subsequently followed with full length sequencing by a clone-by-clone primer walking method. The complete cDNA consists of 890 nucleotides, including an ORF encoding 196 amino acid residues. Excluding a putative signal peptide of the first 20 amino acid residues, the 176-residue mature apoLp-III has a calculated molecular mass of 19,146 Da. Genomic sequence analysis with respect to its cDNA showed that TmapoLp-III was organized into four exons interrupted by three introns. Several immune-related transcription factor binding sites were discovered in the putative 5’-flanking region. BLAST and phylogenetic analysis reveals that TmapoLp-III has high sequence identity (88%) with Tribolium castaneum apoLp-III but shares little sequence homologies (<26%) with other apoLp-IIIs. Homology modeling of Tm apoLp-III shows a bundle of five amphipathic helices, including a short helix 3’. The ‘helix-short helix-helix’ motif was predicted to be implicated in lipid binding interactions, through reversible conformational changes and accommodating the hydrophobic residues to the exterior for stability. Highest level of TmapoLp-III mRNA was detected at late pupal stages, albeit it is expressed in the larval and adult stages at lower levels. The tissue specific expression of the transcripts showed significantly higher numbers in larval fat body and adult integument. In addition, TmapoLp-III mRNA was found to be highly up-regulated in late stages of L. monocytogenes or E. coli challenge. These results indicate that TmapoLp-III may play an important role in innate immune responses against bacterial pathogens in T. molitor.
        8.
        2013.10 구독 인증기관·개인회원 무료
        To investigate genes differentially expressed in the venom of social and solitary wasps, a comparative transcriptome analysis was conducted. Subtractive expressed sequence tag (EST) libraries specific to the venom gland and sac (gland/sac) of a social wasp species, Vespa tropica and a solitary hunting wasp species, Rhynchium brunneum, was constructed by suppression subtractive hybridization. In BLASTx analysis, 41% and 56% of the total ESTs showed statistically best-matched hits (E ≤ 10-4) in the libraries of V. tropica and R. brunneum, respectively. Although the functional category analysis did not show remarkable differences in the distribution of functional categories between the two venom gland/sac cDNA libraries, perhaps due to the lack of functional information on many of the venom components, there were groups of genes that are specific to either V. tropica or R. brunneum. Venom allergen 5 and serine protease were found to be social wasp-specific venom transcripts. In contrast, venom peptides, metalloendopeptidases, arginine kinase and dendrotoxin were observed in solitary wasp at much higher frequencies.
        9.
        2012.10 구독 인증기관·개인회원 무료
        To identify whether higher expression of carboxylesterase (CbE) E4 in Myzus persicae is due to gene duplication, gene copy number was determined by quantitative real-time PCR. In addition, to determine the actual protein concentration of CbE E4 and it activity, Western blotting and activity staining were conducted. CbE gene copy number was highly correlated with carbamate resistance ratio (r2=0.934). However, CbE E4 expression level was little correlated with insecticide resistance ratio (r2<0.046) and no apparent correlation was observed among the gene copy number, protein quantity and total activity of CbE E4. Therefore, it was assumed that not only quantitative changing but also qualitative alteration of CbE E4 occurred in M. persicae. To investigate any potential alteration of CbE E4, mutation survey was conducted by sequencing of CbE E4 from various local strains of M. persicae. G137D and W251L mutations have been known as the main mutations associated with structural change leading to resistance. Interestingly, a new G134C mutation, which is in proximity of G137D mutation, was identified in the oxyanion hole of CbE E4. To predict the functional role of this mutation in resistance, 3-dimensional structure modeling was conducted. In summary, CbE E4 appears to be involved in resistance to both pyrethroids and carbamates as a nonspecific hydrolase or sequestration protein in M. persicae.
        10.
        2011.10 구독 인증기관·개인회원 무료
        The green peach aphid (Myzus persicae) is a cosmopolitan pest of agricultural and horticultural crops and causes serious economic damages. M. persica has rapidly developed resistance to a wide variety of insecticides, including pyrethroids. Target site insensitivity mechanism mediated by two mutations (L1014F and M918T) on the para-type voltage-sensitive sodium channel (vssc) is mainly responsible for pyrethroid resistance. To predict the vssc resistance allele frequency, quantitative sequencing (QS) protocol was established. Frequency prediction equations generated from the plots of signal ratios and amplification critical time showed a high correlation coefficient (r2>0.993), indicating its high accuracy in prediction. QS results revealed that the kdr-type L1014F mutation is only present in Pyeongchang strain. No field strains of M. persicae possessed the super-kdr type M918T mutation. However, a novel M918L mutation was found by genotyping approach. The allele frequencies of M918L and L1014F were 0% to 53% in populations examined, and the level of M918L mutation frequency was closely related with pyrethroid resistance. Therefore, QS-based detection of M918L mutation frequency should faciltate the monitoring of pyrethroid resistance in the field.
        11.
        2011.10 구독 인증기관·개인회원 무료
        The green peach aphid (Myzus persicae) is a serious pest of agricultural and horticultural crops all over the world. M. persica has rapidly developed resistance to a wide variety of insecticides, including carbamates. The E4/FE4 carboxylesterase is known to be involved in carbamate resistance. To compare the E4/FE4 carboxylesterase gene copy number, as a genetic resistance marker, between seven field strains, quantitative real-time PCR (qPCR) was performed. In addition, quantitative sequencing (QS) was employed to predict the frequencies of acetylcholinesterase (AChE) mutations (A301S and S431F) that are associated with target site insensitivity. All M. persica strains examined possessed the S431F mutation in the heterozygous state except for a susceptible strain, implying the possibility of AChE duplication. In contrast, no A301S mutation was found. Frequency prediction equation was generated from the plots of signal ratios and amplification critical time, which showed a high correlation (r2>0.996). QS analysis of M. persicae populations revealed that the allele frequency of S431F ranged 4% to 63%. Taken together, the AChE resistance allele frequencies determined by QS and the E4/FE4 gene copy number by qPCR should facilitate the detection and monitoring of carbamate resistance in M. persicae in the field.
        12.
        2011.10 구독 인증기관·개인회원 무료
        Rhynchium brunneum is a widely distributed wasp species in South Eastern Asia. R. brunneum females were collected from rural provinces of Cambodia, and their total RNA and venom were extracted on site. To search for novel substances in venom, a subtracted cDNA library specific to the venom gland and sac was constructed. A total of 1118 expressed sequenced sequence tags (ESTs) were sequenced and assembled into 349 contigs (107 multiple sequences and 242 singletons). In this result, we found the putative neurotoxin (DTX protein precursor), antimicrobial peptides (teratocyte-specific caboxylesterase) together with typical major components of wasp venom (venom hyaluronidase, arginine kinase, phospholipase A2, serine/theonine protein phosphatase). Additional in-depth annotation would be required for further characterization of many unidentified genes found in the EST library.
        13.
        2011.05 구독 인증기관·개인회원 무료
        Vespa tropica is a tropical species of Vespa found in Southeast Asia. V. tropica wasps were collected from rural provinces of Cambodia, and their total RNA and venom were extracted on site. To search for novel substances in venom, a subtracted cDNA library specific to the venom gland and sac was constructed and venom protein was analyzed by nano-LC-MS/MS. A total of 1127 expressed sequenced sequence tags (ESTs) were sequenced and assembled into 572 contigs (152 multiple sequences and 420 singletons). The short venom peptides were identified to be encoded from 5 contigs (43 ESTs) by proteomic analysis. In addition, putative antimicrobial peptides together with typical major components of wasp venom (venom allergen 5, mastoparan-like peptide, serine protease, and hyaluronidase) were identified in the EST Library. Additional in-depth annotation would be required for further characterization of many unidentified genes found in the EST library.
        14.
        2010.10 구독 인증기관·개인회원 무료
        Insects or insect remains found in beer are one of major issues in consumer claim. Accurate estimation of inflow time isa critical factor for the settlement of such claims related with beer-contaminating insects but no reliable methods have been developed. In an attempt to establish a molecular marker-based diagnostic method, the degradation rates of 18S rRNA genes in the insectssoaked in 500 ml beer were investigated by quantitative real-time PCR (qPCR) over one month period at room temperature. Among the six insect species tested, the house fly (Musca domestica) and honey bee (Apis mellifera) revealed high correlations (r2=0.974-0.990) between the degradation of 18S rRNA gene and inflow time. In these insects, statistically significant distinction was possible between the samples stored in beer less than 14 days and more than 14 days. Other insects, including the fruit fly, common house mosquito, German cockroach and Indian meal moth, displayed poor correlations, which appeared attributed to the inefficient genomic DNA extraction likely due to small sample size or disintegration of body parts during storage in beer. With proper improvement in DNA extraction, this 18S rRNA-based diagnostic method would be applicable for estimating the inflow time of beer-contaminating insects.
        15.
        2010.05 구독 인증기관·개인회원 무료
        The hemipteran whitefly Bemisia tabaci (Gennadius) is one of the most destructive pests damaging more than 600 agricultural crop species worldwide. The B and Q biotypes are most widely spread in Korea but they are not distinguishable based on morphological characters. Carboxylesterase 2 (Coe2) was determined to be 5.9 times more expressed in B biotype compared to Q biotype. Comparison of deduced amino acid sequences of Coe2 (595 a.a.) showed a total of 3.85% polymorphisms between B and Q types but no differences in major active sites. Quantitative real-time PCR revealed that both B and Q biotypes possess a single copy of coe2, suggesting that the overexpression of Coe2 in B biotype is likely due to overtranscription. To determine the putative role of Coe2 in insecticide tolerance, esterases were separated by native isoelectric focusing (IEF) and inhibited by various insecticides. The putative Coe2 band was apparently inhibited by pyrethroid and organophosphate insecticides, but not by imidacloprid. These findings suggest that overexpression of Coe2 confers chemical defense against pyrethroid and organophosphate insecticides, perhaps by sequestration.
        16.
        2015.12 서비스 종료(열람 제한)
        Background: We evaluated the effect of ulinastatin on paw withdrawal threshold (PWT), IL-6, and IL-10 in SD rats after spinal nerve ligation (SNL). Methods: Group C received N/S and Group E received ulinastatin IV for three days following SNL. PWT, IL-6, and IL-10 were measured on the 3rd, 5th, and 7th day. Results: Group E showed higher PWT compared to group C. IL-6 was lower in group E than in group C. No differences in IL-10 were observed between group C and group E. Conclusion: Ulinastatin increased the PWT and its effect appears to be involved with IL-6, not IL-10.
        17.
        2012.12 KCI 등재 서비스 종료(열람 제한)
        Totally, 26 collections, 17 from Korea and 9 from China, were investigated for their sequences of 5S rDNA, especially the non-transcribed spacers (NTSs). Sequences of 5S rDNA were isolated by PCR using the primers, 5s-rRNA1 and 5s-rRNA2. Genomic DNA PCR produced single amplification of 300, 330, or 350 base pair fragments. Sequence analysis revealed that all inserts contained the part of 5S rDNA gene sequence and the full length of the NTS region. Three different sizes of the fragments were confirmed due to different size of NTS and their length were 300bp, 330bp and 350bp, respectively. Among 17 Korean foxtail millets tested, 14 collections showed single 300bp amplification. Longest fragment amplification, 350bp, was obtained only from the foxtail millet from China origin, even though 2 of them include 300bp fragment. CLUSTALW multiple alignments of 26 foxtail millets clearly revealed 4 areas with certain degree of sequence heterogeneity (region I, II, III, IV). Among 4 boxed areas, foxtail millet genotypes from China have distinct insertion especially in region III. Five of them have extra insertion of sequence and their additional sequences were either 45 or 48 base pair. Three Korean foxtail millets have 32 bp insertion. Other 8 Korean collections have short insert sequences (6 to 8 bp), 3 with 8 bp and 5 with 6 bp. In addition to insert, deletion sequences were also confirmed as major deletion was observed in region II of Chinese collection. The size of deletion was 7 bp long. According to phylogenic tree constructed using MEGA4 program, clear grouping was not revealed. To obtain more convincing results various collections from many countries should be obtained and analyzed to distinguish different germplasm from different origin.
        18.
        2012.12 KCI 등재 서비스 종료(열람 제한)
        Twenty two common millet (Panicum miliaceum L.) varieties collected from Korea, China and Russia were investigated for their phylogenetic relationship using 5S ribosomal DNA sequences with a hope to provide the basic information on their exact origin. Sequences of 5S rDNA were isolated by PCR. The primers, 5s-rRNA1 and 5s-rRNA2, were designed to isolate the complete NTS. Genomic DNA amplification produced two fragments with different length, 900 bp and 400 bp fragments, confirming the presence of two types of 5S rDNA repeats that differed from each other in the length of the NTS region. Amplified DNAs of 400 bp fragment were subcloned and used for further investigation. The obtained NTS sequences ranged from 200 to 300 bp and homology of sequences among plant materials was much higher than long repeat. CLUSTALW multiple aligment of 5S rDNA sequences from 22 different common millets revealed the clear difference by their origin. And critically different areas with insert or deletion were also confirmed. Those sequence difference seems to be used for discrimination of cultivars from different origin and use as molecular markers for origin identification. In phylogenic tree construction, the clear classification was shown where the genotypes from China and Russia is positioned together and stay away from domestic genotypes.