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Sample records for intergenic spacer regions

  1. [Identification of medicinal plant Dendrobium based on the chloroplast psbK-psbI intergenic spacer].

    Science.gov (United States)

    Yao, Hui; Yang, Pei; Zhou, Hong; Ma, Shuang-jiao; Song, Jing-yuan; Chen, Shi-lin

    2015-06-01

    In this paper, the chloroplast psbK-psbI intergenic spacers of 18 species of Dendrobium and their adulterants were amplified and sequenced, and then the sequence characteristics were analyzed. The sequence lengths of chloroplast psbK-psbI regions of Dendrobium ranged from 474 to 513 bp and the GC contents were 25.4%-27.6%. The variable sites were 71 while the informative sites were 46. The inter-specific genetic distances calculated by Kimura 2-parameter (K2P) of Dendrobium were 0.006 1-0.058 1, with an average of 0.028 4. The K2P genetic distances between Dendrobium species and Bulbophyllum odoratissimum were 0.093 2-0.120 4. The NJ tree showed that the Dendrobium species can be easily differentiated from each other and 6 samples of the inspected Dendrobium species were identified successfully through sequencing the psbK-psbI intergenic spacer. Therefore, the chloroplast psbK-psbI intergenic spacer can be used as a candidate marker to identify Dendrobium species and its adulterants.

  2. Novel Bacteriocinogenic Lactobacillus plantarum Strains and Their Differentiation by Sequence Analysis of 16S rDNA, 16S-23S and 23S-5S Intergenic Spacer Regions and Randomly Amplified Polymorphic DNA Analysis

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    Morteza Shojaei Moghadam

    2010-01-01

    Full Text Available Six strains of bacteriocinogenic Lactobacillus plantarum (TL1, RG11, RS5, UL4, RG14 and RI11 isolated from Malaysian foods were investigated for their structural bacteriocin genes. A new combination of plantaricin EF and plantaricin W bacteriocin structural genes was successfully amplified from all studied strains, suggesting that they were novel bacteriocin-producing L. plantarum strains. A four-base pair variable region was detected in the short 16S-23S intergenic spacer regions of the studied strains by a comparative analysis with 17 L. plantarum strains deposited in the GenBank, implying they were new genotypes. The studied L. plantarum strains were subsequently differentiated into four groups on the basis of the detected four-base pair variable region of the short 16S-23S intergenic spacer region. Further analysis of the DNA sequence of 23S-5S intergenic spacer region revealed only one type of 23S-5S intergenic spacer region present in the studied strains, indicating it was highly conserved among the studied L. plantarum strains. Three randomly amplified polymorphic DNA experiments using three different combinations of arbitrary primers successfully differentiated the studied L. plantarum strains from each other, confirming they were different strains. In conclusion, the studied L. plantarum strains were shown to be novel bacteriocin producers and high level of strain discrimination could be achieved with a combination of randomly amplified polymorphic DNA analysis and the analysis of the variable region of short 16S-23S intergenic spacer region present in L. plantarum strains.

  3. Bat white-nose syndrome: A real-time TaqMan polymerase chain reaction test targeting the intergenic spacer region of Geomyces destructans

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    Laura K Muller; Jeffrey M. Lorch; Daniel L. Lindner; Michael O' Connor; Andrea Gargas; David S. Blehert

    2013-01-01

    The fungus Geomyces destructans is the causative agent of white-nose syndrome (WNS), a disease that has killed millions of North American hibernating bats. We describe a real-time TaqMan PCR test that detects DNA from G. destructans by targeting a portion of the multicopy intergenic spacer region of the rRNA gene complex. The...

  4. An improved PCR method for direct identification of Porphyra (Bangiales, Rhodophyta) using conchocelis based on a RUBISCO intergenic spacer

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    Wang, Chao; Dong, Dong; Wang, Guangce; Zhang, Baoyu; Peng, Guang; Xu, Pu; Tang, Xiaorong

    2009-09-01

    An improved method of PCR in which the small segment of conchocelis is amplified directly without DNA extraction was used to amplify a RUBISCO intergenic spacer DNA fragment from nine species of red algal genus Porphyra (Bangiales, Rhodophyta), including Porphyra yezoensis (Jiangsu, China), P. haitanensis (Fujian, China), P. oligospermatangia (Qingdao, China), P. katadai (Qingdao, China), P. tenera (Qingdao, China), P. suborboculata (Fujian, China), P. pseudolinearis (Kogendo, Korea), P. linearis (Devon, England), and P. fallax (Seattle, USA). Standard PCR and the method developed here were both conducted using primers specific for the RUBISCO spacer region, after which the two PCR products were sequenced. The sequencing data of the amplicons obtained using both methods were identical, suggesting that the improved PCR method was functional. These findings indicate that the method developed here may be useful for the rapid identification of species of Porphyra in a germplasm bank. In addition, a phylogenetic tree was constructed using the RUBISCO spacer and partial rbcS sequence, and the results were in concordant with possible alternative phylogenies based on traditional morphological taxonomic characteristics, indicating that the RUBISCO spacer is a useful region for phylogenetic studies.

  5. Identification of Dendrobium species by a candidate DNA barcode sequence: the chloroplast psbA-trnH intergenic region.

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    Yao, Hui; Song, Jing-Yuan; Ma, Xin-Ye; Liu, Chang; Li, Ying; Xu, Hong-Xi; Han, Jian-Ping; Duan, Li-Sheng; Chen, Shi-Lin

    2009-05-01

    DNA barcoding is a novel technology that uses a standard DNA sequence to facilitate species identification. Although a consensus has not been reached regarding which DNA sequences can be used as the best plant barcodes, the psbA-trnH spacer region has been tested extensively in recent years. In this study, we hypothesize that the psbA-trnH spacer regions are also effective barcodes for Dendrobium species. We have sequenced the chloroplast psbA-trnH intergenic spacers of 17 Dendrobium species to test this hypothesis. The sequences were found to be significantly different from those of other species, with percentages of variation ranging from 0.3 % to 2.3 % and an average of 1.2 %. In contrast, the intraspecific variation among the Dendrobium species studied ranged from 0 % to 0.1 %. The sequence difference between the psbA-trnH sequences of 17 Dendrobium species and one Bulbophyllum odoratissimum ranged from 2.0 % to 3.1 %, with an average of 2.5 %. Our results support the notion that the psbA-trnH intergenic spacer region could be used as a barcode to distinguish various Dendrobium species and to differentiate Dendrobium species from other adulterating species. Copyright Georg Thieme Verlag KG Stuttgart. New York.

  6. Bat white-nose syndrome: a real-time TaqMan polymerase chain reaction test targeting the intergenic spacer region of Geomyces destructanstructans.

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    Muller, Laura K.; Lorch, Jeffrey M.; Lindner, Daniel L.; O'Connor, Michael; Gargas, Andrea; Blehert, David S.

    2013-01-01

    The fungus Geomyces destructans is the causative agent of white-nose syndrome (WNS), a disease that has killed millions of North American hibernating bats. We describe a real-time TaqMan PCR test that detects DNA from G. destructans by targeting a portion of the multicopy intergenic spacer region of the rRNA gene complex. The test is highly sensitive, consistently detecting as little as 3.3 fg of genomic DNA from G. destructans. The real-time PCR test specifically amplified genomic DNA from G. destructans but did not amplify target sequence from 54 closely related fungal isolates (including 43 Geomyces spp. isolates) associated with bats. The test was further qualified by analyzing DNA extracted from 91 bat wing skin samples, and PCR results matched histopathology findings. These data indicate the real-time TaqMan PCR method described herein is a sensitive, specific, and rapid test to detect DNA from G. destructans and provides a valuable tool for WNS diagnostics and research.

  7. Paenibacillus larvae 16S-23S rDNA intergenic transcribed spacer (ITS) regions: DNA fingerprinting and characterization.

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    Dingman, Douglas W

    2012-07-01

    Paenibacillus larvae is the causative agent of American foulbrood in honey bee (Apis mellifera) larvae. PCR amplification of the 16S-23S ribosomal DNA (rDNA) intergenic transcribed spacer (ITS) regions, and agarose gel electrophoresis of the amplified DNA, was performed using genomic DNA collected from 134 P. larvae strains isolated in Connecticut, six Northern Regional Research Laboratory stock strains, four strains isolated in Argentina, and one strain isolated in Chile. Following electrophoresis of amplified DNA, all isolates exhibited a common migratory profile (i.e., ITS-PCR fingerprint pattern) of six DNA bands. This profile represented a unique ITS-PCR DNA fingerprint that was useful as a fast, simple, and accurate procedure for identification of P. larvae. Digestion of ITS-PCR amplified DNA, using mung bean nuclease prior to electrophoresis, characterized only three of the six electrophoresis bands as homoduplex DNA and indicating three true ITS regions. These three ITS regions, DNA migratory band sizes of 915, 1010, and 1474 bp, signify a minimum of three types of rrn operons within P. larvae. DNA sequence analysis of ITS region DNA, using P. larvae NRRL B-3553, identified the 3' terminal nucleotides of the 16S rRNA gene, 5' terminal nucleotides of the 23S rRNA gene, and the complete DNA sequences of the 5S rRNA, tRNA(ala), and tRNA(ile) genes. Gene organization within the three rrn operon types was 16S-23S, 16S-tRNA(ala)-23S, and l6S-5S-tRNA(ile)-tRNA(ala)-23S and these operons were named rrnA, rrnF, and rrnG, respectively. The 23S rRNA gene was shown by I-CeuI digestion and pulsed-field gel electrophoresis of genomic DNA to be present as seven copies. This was suggestive of seven rrn operon copies within the P. larvae genome. Investigation of the 16S-23S rDNA regions of this bacterium has aided the development of a diagnostic procedure and has helped genomic mapping investigations via characterization of the ITS regions. Copyright © 2012 Elsevier Inc

  8. A ribosomal RNA gene intergenic spacer based PCR and DGGE fingerprinting method for the analysis of specific rhizobial communities in soil

    NARCIS (Netherlands)

    de Oliveira, VM; Manfio, GP; Coutinho, HLD; Keijzer-Wolters, AC; van Elsas, JD

    A direct molecular method for assessing the diversity of specific populations of rhizobia in soil, based on nested PCR amplification of 16S-23S ribosomal RNA gene (rDNA) intergenic spacer (IGS) sequences, was developed. Initial generic amplification of bacterial rDNA IGS sequences from soil DNA was

  9. A ribosomal RNA gene intergenic spacer based PCR and DGGE fingerprinting method for the analysis of specific rhizobial communities in soil

    NARCIS (Netherlands)

    Oliveira, de V.M.; Manfio, G.P.; Coutinho, H.L.D.; Keijzer-Wolters, A.C.; Elsas, van J.D.

    2006-01-01

    A direct molecular method for assessing the diversity of specific populations of rhizobia in soil, based on nested PCR amplification of 16S-23S ribosomal RNA gene (rDNA) intergenic spacer (IGS) sequences, was developed. Initial generic amplification of bacterial rDNA IGS sequences from soil DNA was

  10. Ribosomal DNA intergenic spacer sequence in foxtail millet, Setaria italica (L.) P. Beauv. and its characterization and application to typing of foxtail millet landraces.

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    Fukunaga, Kenji; Ichitani, Katsuyuki; Taura, Satoru; Sato, Muneharu; Kawase, Makoto

    2005-02-01

    We determined the sequence of ribosomal DNA (rDNA) intergenic spacer (IGS) of foxtail millet isolated in our previous study, and identified subrepeats in the polymorphic region. We also developed a PCR-based method for identifying rDNA types based on sequence information and assessed 153 accessions of foxtail millet. Results were congruent with our previous works. This study provides new findings regarding the geographical distribution of rDNA variants. This new method facilitates analyses of numerous foxtail millet accessions. It is helpful for typing of foxtail millet germplasms and elucidating the evolution of this millet.

  11. Evolution of the rpoB-psbZ region in fern plastid genomes: notable structural rearrangements and highly variable intergenic spacers.

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    Gao, Lei; Zhou, Yuan; Wang, Zhi-Wei; Su, Ying-Juan; Wang, Ting

    2011-04-13

    The rpoB-psbZ (BZ) region of some fern plastid genomes (plastomes) has been noted to go through considerable genomic changes. Unraveling its evolutionary dynamics across all fern lineages will lead to clarify the fundamental process shaping fern plastome structure and organization. A total of 24 fern BZ sequences were investigated with taxon sampling covering all the extant fern orders. We found that: (i) a tree fern Plagiogyria japonica contained a novel gene order that can be generated from either the ancestral Angiopteris type or the derived Adiantum type via a single inversion; (ii) the trnY-trnE intergenic spacer (IGS) of the filmy fern Vandenboschia radicans was expanded 3-fold due to the tandem 27-bp repeats which showed strong sequence similarity with the anticodon domain of trnY; (iii) the trnY-trnE IGSs of two horsetail ferns Equisetum ramosissimum and E. arvense underwent an unprecedented 5-kb long expansion, more than a quarter of which was consisted of a single type of direct repeats also relevant to the trnY anticodon domain; and (iv) ycf66 has independently lost at least four times in ferns. Our results provided fresh insights into the evolutionary process of fern BZ regions. The intermediate BZ gene order was not detected, supporting that the Adiantum type was generated by two inversions occurring in pairs. The occurrence of Vandenboschia 27-bp repeats represents the first evidence of partial tRNA gene duplication in fern plastomes. Repeats potentially forming a stem-loop structure play major roles in the expansion of the trnY-trnE IGS.

  12. Evolution of the rpoB-psbZ region in fern plastid genomes: notable structural rearrangements and highly variable intergenic spacers

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    Su Ying-Juan

    2011-04-01

    Full Text Available Abstract Background The rpoB-psbZ (BZ region of some fern plastid genomes (plastomes has been noted to go through considerable genomic changes. Unraveling its evolutionary dynamics across all fern lineages will lead to clarify the fundamental process shaping fern plastome structure and organization. Results A total of 24 fern BZ sequences were investigated with taxon sampling covering all the extant fern orders. We found that: (i a tree fern Plagiogyria japonica contained a novel gene order that can be generated from either the ancestral Angiopteris type or the derived Adiantum type via a single inversion; (ii the trnY-trnE intergenic spacer (IGS of the filmy fern Vandenboschia radicans was expanded 3-fold due to the tandem 27-bp repeats which showed strong sequence similarity with the anticodon domain of trnY; (iii the trnY-trnE IGSs of two horsetail ferns Equisetum ramosissimum and E. arvense underwent an unprecedented 5-kb long expansion, more than a quarter of which was consisted of a single type of direct repeats also relevant to the trnY anticodon domain; and (iv ycf66 has independently lost at least four times in ferns. Conclusions Our results provided fresh insights into the evolutionary process of fern BZ regions. The intermediate BZ gene order was not detected, supporting that the Adiantum type was generated by two inversions occurring in pairs. The occurrence of Vandenboschia 27-bp repeats represents the first evidence of partial tRNA gene duplication in fern plastomes. Repeats potentially forming a stem-loop structure play major roles in the expansion of the trnY-trnE IGS.

  13. 16S-23S rDNA intergenic spacer region polymorphism of Lactococcus garvieae, Lactococcus raffinolactis and Lactococcus lactis as revealed by PCR and nucleotide sequence analysis.

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    Blaiotta, Giuseppe; Pepe, Olimpia; Mauriello, Gianluigi; Villani, Francesco; Andolfi, Rosamaria; Moschetti, Giancarlo

    2002-12-01

    The intergenic spacer region (ISR) between the 16S and 23S rRNA genes was tested as a tool for differentiating lactococci commonly isolated in a dairy environment. 17 reference strains, representing 11 different species belonging to the genera Lactococcus, Streptococcus, Lactobacillus, Enterococcus and Leuconostoc, and 127 wild streptococcal strains isolated during the whole fermentation process of "Fior di Latte" cheese were analyzed. After 16S-23S rDNA ISR amplification by PCR, species or genus-specific patterns were obtained for most of the reference strains tested. Moreover, results obtained after nucleotide analysis show that the 16S-23S rDNA ISR sequences vary greatly, in size and sequence, among Lactococcus garvieae, Lactococcus raffinolactis, Lactococcus lactis as well as other streptococci from dairy environments. Because of the high degree of inter-specific polymorphism observed, 16S-23S rDNA ISR can be considered a good potential target for selecting species-specific molecular assays, such as PCR primer or probes, for a rapid and extremely reliable differentiation of dairy lactococcal isolates.

  14. Optimisation of automated ribosomal intergenic spacer analysis for the estimation of microbial diversity in fynbos soil

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    Karin Jacobs

    2010-07-01

    Full Text Available Automated ribosomal intergenic spacer analysis (ARISA has become a commonly used molecular technique for the study of microbial populations in environmental samples. The reproducibility and accuracy of ARISA, with and without the polymerase chain reaction (PCR are important aspects that influence the results and effectiveness of these techniques. We used the primer set ITS4/ITS5 for ARISA to assess the fungal community composition of two sites situated in the Sand Fynbos. The primer set proved to deliver reproducible ARISA profiles of the fungal community composition with little variation observed between ARISA-PCRs. Variation that occurred in a sample due to repeated DNA extraction is expected for ecological studies. This reproducibility made ARISA a useful tool for the assessment and comparison of diversity in ecological samples. In this paper, we also offered particular suggestions concerning the binning strategy for the analysis of ARISA profiles.

  15. Variation of 45S rDNA intergenic spacers in Arabidopsis thaliana.

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    Havlová, Kateřina; Dvořáčková, Martina; Peiro, Ramon; Abia, David; Mozgová, Iva; Vansáčová, Lenka; Gutierrez, Crisanto; Fajkus, Jiří

    2016-11-01

    Approximately seven hundred 45S rRNA genes (rDNA) in the Arabidopsis thaliana genome are organised in two 4 Mbp-long arrays of tandem repeats arranged in head-to-tail fashion separated by an intergenic spacer (IGS). These arrays make up 5 % of the A. thaliana genome. IGS are rapidly evolving sequences and frequent rearrangements inside the rDNA loci have generated considerable interspecific and even intra-individual variability which allows to distinguish among otherwise highly conserved rRNA genes. The IGS has not been comprehensively described despite its potential importance in regulation of rDNA transcription and replication. Here we describe the detailed sequence variation in the complete IGS of A. thaliana WT plants and provide the reference/consensus IGS sequence, as well as genomic DNA analysis. We further investigate mutants dysfunctional in chromatin assembly factor-1 (CAF-1) (fas1 and fas2 mutants), which are known to have a reduced number of rDNA copies, and plant lines with restored CAF-1 function (segregated from a fas1xfas2 genetic background) showing major rDNA rearrangements. The systematic rDNA loss in CAF-1 mutants leads to the decreased variability of the IGS and to the occurrence of distinct IGS variants. We present for the first time a comprehensive and representative set of complete IGS sequences, obtained by conventional cloning and by Pacific Biosciences sequencing. Our data expands the knowledge of the A. thaliana IGS sequence arrangement and variability, which has not been available in full and in detail until now. This is also the first study combining IGS sequencing data with RFLP analysis of genomic DNA.

  16. Suitability of the molecular subtyping methods intergenic spacer region, direct genome restriction analysis, and pulsed-field gel electrophoresis for clinical and environmental Vibrio parahaemolyticus isolates.

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    Lüdeke, Catharina H M; Fischer, Markus; LaFon, Patti; Cooper, Kara; Jones, Jessica L

    2014-07-01

    Vibrio parahaemolyticus is the leading cause of infectious illness associated with seafood consumption in the United States. Molecular fingerprinting of strains has become a valuable research tool for understanding this pathogen. However, there are many subtyping methods available and little information on how they compare to one another. For this study, a collection of 67 oyster and 77 clinical V. parahaemolyticus isolates were analyzed by three subtyping methods--intergenic spacer region (ISR-1), direct genome restriction analysis (DGREA), and pulsed-field gel electrophoresis (PFGE)--to determine the utility of these methods for discriminatory subtyping. ISR-1 analysis, run as previously described, provided the lowest discrimination of all the methods (discriminatory index [DI]=0.8665). However, using a broader analytical range than previously reported, ISR-1 clustered isolates based on origin (oyster versus clinical) and had a DI=0.9986. DGREA provided a DI=0.9993-0.9995, but did not consistently cluster the isolates by any identifiable characteristics (origin, serotype, or virulence genotype) and ∼ 15% of isolates were untypeable by this method. PFGE provided a DI=0.9998 when using the combined pattern analysis of both restriction enzymes, SfiI and NotI. This analysis was more discriminatory than using either enzyme pattern alone and primarily grouped isolates by serotype, regardless of strain origin (clinical or oyster) or presence of currently accepted virulence markers. These results indicate that PFGE and ISR-1 are more reliable methods for subtyping V. parahemolyticus, rather than DGREA. Additionally, ISR-1 may provide an indication of pathogenic potential; however, more detailed studies are needed. These data highlight the diversity within V. parahaemolyticus and the need for appropriate selection of subtyping methods depending on the study objectives.

  17. Intergenic disease-associated regions are abundant in novel transcripts.

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    Bartonicek, N; Clark, M B; Quek, X C; Torpy, J R; Pritchard, A L; Maag, J L V; Gloss, B S; Crawford, J; Taft, R J; Hayward, N K; Montgomery, G W; Mattick, J S; Mercer, T R; Dinger, M E

    2017-12-28

    Genotyping of large populations through genome-wide association studies (GWAS) has successfully identified many genomic variants associated with traits or disease risk. Unexpectedly, a large proportion of GWAS single nucleotide polymorphisms (SNPs) and associated haplotype blocks are in intronic and intergenic regions, hindering their functional evaluation. While some of these risk-susceptibility regions encompass cis-regulatory sites, their transcriptional potential has never been systematically explored. To detect rare tissue-specific expression, we employed the transcript-enrichment method CaptureSeq on 21 human tissues to identify 1775 multi-exonic transcripts from 561 intronic and intergenic haploblocks associated with 392 traits and diseases, covering 73.9 Mb (2.2%) of the human genome. We show that a large proportion (85%) of disease-associated haploblocks express novel multi-exonic non-coding transcripts that are tissue-specific and enriched for GWAS SNPs as well as epigenetic markers of active transcription and enhancer activity. Similarly, we captured transcriptomes from 13 melanomas, targeting nine melanoma-associated haploblocks, and characterized 31 novel melanoma-specific transcripts that include fusion proteins, novel exons and non-coding RNAs, one-third of which showed allelically imbalanced expression. This resource of previously unreported transcripts in disease-associated regions ( http://gwas-captureseq.dingerlab.org ) should provide an important starting point for the translational community in search of novel biomarkers, disease mechanisms, and drug targets.

  18. Evaluation of Automated Ribosomal Intergenic Spacer Analysis for Bacterial Fingerprinting of Rumen Microbiome Compared to Pyrosequencing Technology

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    Elie Jami

    2014-01-01

    Full Text Available The mammalian gut houses a complex microbial community which is believed to play a significant role in host physiology. In recent years, several microbial community analysis methods have been implemented to study the whole gut microbial environment, in contrast to classical microbiological methods focusing on bacteria which can be cultivated. One of these is automated ribosomal intergenic spacer analysis (ARISA, an inexpensive and popular way of analyzing bacterial diversity and community fingerprinting in ecological samples. ARISA uses the natural variability in length of the DNA fragment found between the 16S and 23S genes in different bacterial lineages to infer diversity. This method is now being supplanted by affordable next-generation sequencing technologies that can also simultaneously annotate operational taxonomic units for taxonomic identification. We compared ARISA and pyrosequencing of samples from the rumen microbiome of cows, previously sampled at different stages of development and varying in microbial complexity using several ecological parameters. We revealed close agreement between ARISA and pyrosequencing outputs, especially in their ability to discriminate samples from different ecological niches. In contrast, the ARISA method seemed to underestimate sample richness. The good performance of the relatively inexpensive ARISA makes it relevant for straightforward use in bacterial fingerprinting analysis as well as for quick cross-validation of pyrosequencing data.

  19. Rapid identification of 11 human intestinal Lactobacillus species by multiplex PCR assays using group- and species-specific primers derived from the 16S-23S rRNA intergenic spacer region and its flanking 23S rRNA.

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    Song, Y; Kato, N; Liu, C; Matsumiya, Y; Kato, H; Watanabe, K

    2000-06-15

    Rapid and reliable two-step multiplex polymerase chain reaction (PCR) assays were established to identify human intestinal lactobacilli; a multiplex PCR was used for grouping of lactobacilli with a mixture of group-specific primers followed by four multiplex PCR assays with four sorts of species-specific primer mixtures for identification at the species level. Primers used were designed from nucleotide sequences of the 16S-23S rRNA intergenic spacer region and its flanking 23S rRNA gene of members of the genus Lactobacillus which are commonly isolated from human stool specimens: Lactobacillus acidophilus, Lactobacillus crispatus, Lactobacillus delbrueckii (ssp. bulgaricus and ssp. lactis), Lactobacillus fermentum, Lactobacillus gasseri, Lactobacillus jensenii, Lactobacillus paracasei (ssp. paracasei and ssp. tolerans), Lactobacillus plantarum, Lactobacillus reuteri, Lactobacillus rhamnosus and Lactobacillus salivarius (ssp. salicinius and ssp. salivarius). The established two-step multiplex PCR assays were applied to the identification of 84 Lactobacillus strains isolated from human stool specimens and the PCR results were consistent with the results from the DNA-DNA hybridization assay. These results suggest that the multiplex PCR system established in this study is a simple, rapid and reliable method for the identification of common Lactobacillus isolates from human stool samples.

  20. Methylation pattern of the intergenic spacer of rRNA genes in excised cotyledons of Cucurbita pepo L. (Zucchini) after hormone treatment

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    Ananiev, E.; Abdulova, G.; Grozdanov, P.; Karagyozov, L.

    2003-01-01

    High molecular mass genomic DNA was isolated from excised marrow cotyledons (Cucurbita pepo L. zucchini) treated with 6-benzyladenine (BA) of methyl ester of jasmonic acid (MeJA) for 24 h in darkness. DNA purified from contaminating polysaccharides with Celite column was completely digested with the restriction enzyme Eco RI and the changes in the methylation pattern of the intergenic spacer (IGS) of r RNA genes were studied after subsequent digestion with the couple of restriction enzymes-isoschizomers MSP I and Hpa II by the method of 'indirect end labelling'. As rDNA units probe a cloned 32 P-labelled Eco RI 2.1 kb fragment spanning in the most part of 18S r RNA gene from flax rDNA was used. Results showed heavy methylation of the rRNA genes. As judged from the almost total lack of digestion with HPA II, there were no methylation free regions in repeated rDNA units or little if any were observed. A hypo methylated Hps II site was detected near the promoter region in some of the repeats. Digestion with Msp I affected nearly 50% of the repeating units. The Msp digestion fragments of the 6.2 kb Eco RI fragment of r DNA were few in number and large in size (0.5 - 2.5 kb). This suggested that in addition with -CpG- sequences, methylation in -CpNpG- might not be random. Methylation pattern in IGS was not changed upon treatment of the cotyledons in vivo with BA and MeJA. Thus, previously observed hormone-mediated effects on the eactivity of rRNA gene expression were not accompanied by any significant changes of the methylation pattern in IGS. (authors)

  1. Population genetic structure and phylogeographical pattern of a relict tree fern, Alsophila spinulosa (Cyatheaceae), inferred from cpDNA atpB- rbcL intergenic spacers.

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    Su, Yingjuan; Wang, Ting; Zheng, Bo; Jiang, Yu; Chen, Guopei; Gu, Hongya

    2004-11-01

    Sequences of chloroplast DNA (cpDNA) atpB- rbcL intergenic spacers of individuals of a tree fern species, Alsophila spinulosa, collected from ten relict populations distributed in the Hainan and Guangdong provinces, and the Guangxi Zhuang region in southern China, were determined. Sequence length varied from 724 bp to 731 bp, showing length polymorphism, and base composition was with high A+T content between 63.17% and 63.95%. Sequences were neutral in terms of evolution (Tajima's criterion D=-1.01899, P>0.10 and Fu and Li's test D*=-1.39008, P>0.10; F*=-1.49775, P>0.10). A total of 19 haplotypes were identified based on nucleotide variation. High levels of haplotype diversity (h=0.744) and nucleotide diversity (Dij=0.01130) were detected in A. spinulosa, probably associated with its long evolutionary history, which has allowed the accumulation of genetic variation within lineages. Both the minimum spanning network and neighbor-joining trees generated for haplotypes demonstrated that current populations of A. spinulosa existing in Hainan, Guangdong, and Guangxi were subdivided into two geographical groups. An analysis of molecular variance indicated that most of the genetic variation (93.49%, P<0.001) was partitioned among regions. Wright's isolation by distance model was not supported across extant populations. Reduced gene flow by the Qiongzhou Strait and inbreeding may result in the geographical subdivision between the Hainan and Guangdong + Guangxi populations (FST=0.95, Nm=0.03). Within each region, the star-like pattern of phylogeography of haplotypes implied a population expansion process during evolutionary history. Gene genealogies together with coalescent theory provided significant information for uncovering phylogeography of A. spinulosa.

  2. Correlation of maple sap composition with bacterial and fungal communities determined by multiplex automated ribosomal intergenic spacer analysis (MARISA).

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    Filteau, Marie; Lagacé, Luc; LaPointe, Gisèle; Roy, Denis

    2011-08-01

    During collection, maple sap is contaminated by bacteria and fungi that subsequently colonize the tubing system. The bacterial microbiota has been more characterized than the fungal microbiota, but the impact of both components on maple sap quality remains unclear. This study focused on identifying bacterial and fungal members of maple sap and correlating microbiota composition with maple sap properties. A multiplex automated ribosomal intergenic spacer analysis (MARISA) method was developed to presumptively identify bacterial and fungal members of maple sap samples collected from 19 production sites during the tapping period. Results indicate that the fungal community of maple sap is mainly composed of yeast related to Mrakia sp., Mrakiella sp., Guehomyces pullulans, Cryptococcus victoriae and Williopsis saturnus. Mrakia, Mrakiella and Guehomyces peaks were identified in samples of all production sites and can be considered dominant and stable members of the fungal microbiota of maple sap. A multivariate analysis based on MARISA profiles and maple sap chemical composition data showed correlations between Candida sake, Janthinobacterium lividum, Williopsis sp., Leuconostoc mesenteroides, Mrakia sp., Rhodococcus sp., Pseudomonas tolaasii, G. pullulans and maple sap composition at different flow periods. This study provides new insights on the relationship between microbial community and maple sap quality. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Phylogenetic relationships in Solanaceae and related species based on cpDNA sequence from plastid trnE-trnT region

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    Danila Montewka Melotto-Passarin

    2008-01-01

    Full Text Available Intergenic spacers of chloroplast DNA (cpDNA are very useful in phylogenetic and population genetic studiesof plant species, to study their potential integration in phylogenetic analysis. The non-coding trnE-trnT intergenic spacer ofcpDNA was analyzed to assess the nucleotide sequence polymorphism of 16 Solanaceae species and to estimate its ability tocontribute to the resolution of phylogenetic studies of this group. Multiple alignments of DNA sequences of trnE-trnT intergenicspacer made the identification of nucleotide variability in this region possible and the phylogeny was estimated by maximumparsimony and rooted with Convolvulaceae Ipomoea batatas, the most closely related family. Besides, this intergenic spacerwas tested for the phylogenetic ability to differentiate taxonomic levels. For this purpose, species from four other families wereanalyzed and compared with Solanaceae species. Results confirmed polymorphism in the trnE-trnT region at different taxonomiclevels.

  4. Phylogenetic relationships in the genus Leonardoxa (Leguminosae: Caesalpinioideae) inferred from chloroplast trnL intron and trnL-trnF intergenic spacer sequences.

    Science.gov (United States)

    Brouat, Carine; Gielly, Ludovic; McKey, Doyle

    2001-01-01

    The African genus LEONARDOXA: (Leguminosae: Caesalpinioideae) comprises two Congolean species and a group of four mostly allopatric subspecies principally located in Cameroon and clustered together in the L. africana complex. LEONARDOXA: provides a good opportunity to investigate the evolutionary history of ant-plant mutualisms, as it exhibits various grades of ant-plant interactions from diffuse to obligate and symbiotic associations. We present in this paper the first molecular phylogenetic study of this genus. We sequenced both the chloroplast DNA trnL intron (677 aligned base pairs [bp]) and trnL-trnF intergene spacer (598 aligned bp). Inferred phylogenetic relationships suggested first that the genus is paraphyletic. The L. africana complex is clearly separated from the two Congolean species, and the integrity of the genus is thus in question. In the L. africana complex, our data showed a lack of congruence between clades suggested by morphological and chloroplast characters. This, and the low level of molecular divergence found between subspecies, suggests gene flow and introgressive events in the L. africana complex.

  5. [Phylogenetic relationships of the species of Oxytropis DC. subg. Oxytropis and Phacoxytropis (Fabaceae) from Asian Russia inferred from the nucleotide sequence analysis of the intergenic spacers of the chloroplast genome].

    Science.gov (United States)

    Kholina, A B; Kozyrenko, M M; Artyukova, E V; Sandanov, D V; Andrianova, E A

    2016-08-01

    The nucleotide sequence analysis of trnH–psbA, trnL–trnF, and trnS–trnG intergenic spacer regions of chloroplast DNA performed in the representatives of the genus Oxytropis from Asian Russia provided clarification of the phylogenetic relationships of some species and sections in the subgenera Oxytropis and Phacoxytropis and in the genus Oxytropis as a whole. Only the section Mesogaea corresponds to the subgenus Phacoxytropis, while the section Janthina of the same subgenus groups together with the sections of the subgenus Oxytropis. The sections Chrysantha and Ortholoma of the subgenus Oxytropis are not only closely related to each other, but together with the section Mesogaea, they are grouped into the subgenus Phacoxytropis. It seems likely that the sections Chrysantha and Ortholoma should be assigned to the subgenus Phacoxytropis, and the section Janthina should be assigned to the subgenus Oxytropis. The molecular differences were identified between O. coerulea and O. mandshurica from the section Janthina that were indicative of considerable divergence of their chloroplast genomes and the species independence of the taxa. The species independence of O. czukotica belonging to the section Arctobia was also confirmed.

  6. Identification of virulence factors in 16S-23S rRNA intergenic spacer genotyped Staphylococcus aureus isolated from water buffaloes and small ruminants.

    Science.gov (United States)

    Cremonesi, P; Zottola, T; Locatelli, C; Pollera, C; Castiglioni, B; Scaccabarozzi, L; Moroni, P

    2013-01-01

    Staphylococcus aureus is an important human and animal pathogen, and is regarded as an important cause of intramammary infection (IMI) in ruminants. Staphylococcus aureus genetic variability and virulence factors have been well studied in veterinary medicine, especially in cows as support for control and management of IMI. The aim of the present study was to genotype 71 Staph. aureus isolates from the bulk tank and foremilk of water buffaloes (n=40) and from udder tissue (n=7) and foremilk (n=24) from small ruminants. The method used was previously applied to bovine Staph. aureus and is based on the amplification of the 16S-23S rRNA intergenic spacer region. The technique applied was able to identify different Staph. aureus genotypes isolated from dairy species other than the bovine species, and cluster the genotypes according to species and herds. Virulence gene distribution was consistent with genotype differentiation. The isolates were also characterized through determination of the presence of 19 virulence-associated genes by specific PCR. Enterotoxins A, C, D, G, I, J, and L were associated with Staph. aureus isolates from buffaloes, whereas enterotoxins C and L were linked to small ruminants. Genes coding for methicillin resistance, Panton-Valentine leukocidin, exfoliative toxins A and B, and enterotoxins B, E, and H were undetected. These findings indicate that RNA template-specific PCR is a valid technique for typing Staph. aureus from buffaloes and small ruminants and is a useful tool for understanding udder infection epidemiology. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  7. Species identification of medicinal pteridophytes by a DNA barcode marker, the chloroplast psbA-trnH intergenic region.

    Science.gov (United States)

    Ma, Xin-Ye; Xie, Cai-Xiang; Liu, Chang; Song, Jing-Yuan; Yao, Hui; Luo, Kun; Zhu, Ying-Jie; Gao, Ting; Pang, Xiao-Hui; Qian, Jun; Chen, Shi-Lin

    2010-01-01

    Medicinal pteridophytes are an important group used in traditional Chinese medicine; however, there is no simple and universal way to differentiate various species of this group by morphological traits. A novel technology termed "DNA barcoding" could discriminate species by a standard DNA sequence with universal primers and sufficient variation. To determine whether DNA barcoding would be effective for differentiating pteridophyte species, we first analyzed five DNA sequence markers (psbA-trnH intergenic region, rbcL, rpoB, rpoC1, and matK) using six chloroplast genomic sequences from GeneBank and found psbA-trnH intergenic region the best candidate for availability of universal primers. Next, we amplified the psbA-trnH region from 79 samples of medicinal pteridophyte plants. These samples represented 51 species from 24 families, including all the authentic pteridophyte species listed in the Chinese pharmacopoeia (2005 version) and some commonly used adulterants. We found that the sequence of the psbA-trnH intergenic region can be determined with both high polymerase chain reaction (PCR) amplification efficiency (94.1%) and high direct sequencing success rate (81.3%). Combined with GeneBank data (54 species cross 12 pteridophyte families), species discriminative power analysis showed that 90.2% of species could be separated/identified successfully by the TaxonGap method in conjunction with the Basic Local Alignment Search Tool 1 (BLAST1) method. The TaxonGap method results further showed that, for 37 out of 39 separable species with at least two samples each, between-species variation was higher than the relevant within-species variation. Thus, the psbA-trnH intergenic region is a suitable DNA marker for species identification in medicinal pteridophytes.

  8. Cytomolecular analysis of ribosomal DNA evolution in a natural allotetraploid Brachypodium hybridum and its putative ancestors – dissecting complex repetitive structure of intergenic spacers

    Directory of Open Access Journals (Sweden)

    Natalia Borowska-Zuchowska

    2016-10-01

    Full Text Available Nucleolar dominance is an epigenetic phenomenon associated with nuclear 35S rRNA genes and consists in selective suppression of gene loci inherited from one of the progenitors in the allopolyploid. Our understanding of the exact mechanisms that determine this process is still fragmentary, especially in case of the grass species. This study aimed to shed some light on the molecular basis of this genome-specific inactivation of 35S rDNA loci in an allotetraploid Brachypodium hybridum (2n=30, which arose from the interspecific hybridization between two diploid ancestors that were very similar to modern B. distachyon (2n=10 and B. stacei (2n=20. Using fluorescence in situ hybridization with 25S rDNA and chromosome-specific BAC clones as probes we revealed that the nucleolar dominance is present not only in meristematic root-tip cells but also in differentiated cell fraction of B. hybridum. Additionally, the intergenic spacers (IGSs from both of the putative ancestors and the allotetraploid were sequenced and analyzed. The presumptive transcription initiation sites, spacer promoters and repeated elements were identified within the IGSs. Two different length variants, 2.3 kb and 3.5 kb, of IGSs were identified in B. distachyon and B. stacei, respectively, however only the IGS that had originated from B. distachyon-like ancestor was present in the allotetraploid. The amplification pattern of B. hybridum IGSs suggests that some genetic changes occurred in inactive B. stacei-like rDNA loci during the evolution of the allotetraploid. We hypothesize that their preferential silencing is an effect of structural changes in the sequence rather than just the result of the sole inactivation at the epigenetic level.

  9. Adaptation of the short intergenic spacers between co-directional genes to the Shine-Dalgarno motif among prokaryote genomes

    DEFF Research Database (Denmark)

    Caro, Albert Pallejà; García-Vallvé, Santiago; Romeu, Antoni

    2009-01-01

    ABSTRACT: BACKGROUND: In prokaryote genomes most of the co-directional genes are in close proximity. Even the coding sequence or the stop codon of a gene can overlap with the Shine-Dalgarno (SD) sequence of the downstream co-directional gene. In this paper we analyze how the presence of SD may...... influence the stop codon usage or the spacing lengths between co-directional genes. RESULTS: The SD sequences for 530 prokaryote genomes have been predicted using computer calculations of the base-pairing free energy between translation initiation regions and the 16S rRNA 3' tail. Genomes with a large...... to the discussion of which factors affect the intergenic lengths, which cannot be totally explained by the pressure to compact the prokaryote genomes....

  10. Differentiation between Aspergillus flavus and Aspergillus parasiticus from Pure Culture and Aflatoxin-Contaminated Grapes Using PCR-RFLP Analysis of aflR-aflJ Intergenic Spacer

    International Nuclear Information System (INIS)

    El Khoury, A.; Atoui, A.; Lebrihi, A.; Rizk, T.; Lteif, R.; Kallassy, M.

    2011-01-01

    Aflatoxins (AFs) represent the most important single mycotoxin-related food safety problem in developed and developing countries as they have adverse effects on human and animal health. They are produced mainly by Aspergillus flavus and A. parasiticus. Both species have different aflatoxinogenic profile. In order to distinguish between A. flavus and A. parasiticus, gene-specific primers were designed to target the intergenic spacer (IGS) for the AF biosynthesis genes, aflJ and aflR. Polymerase chain reaction (PCR) products were subjected to restriction endonuclease analysis using BglII to look for restriction fragment length polymorphisms (RFLPs). Our result showed that both species displayed different PCR-based RFLP (PCR-RFLP) profile. PCR products from A. flavus cleaved into 3 fragments of 362, 210, and 102 bp. However, there is only one restriction site for this enzyme in the sequence of A. parasiticus that produced only 2 fragments of 363 and 311 bp. The method was successfully applied to contaminated grapes samples. This approach of differentiating these 2 species would be simpler, less costly, and quicker than conventional sequencing of PCR products and/or morphological identification. (author)

  11. A ribosomal RNA gene intergenic spacer based PCR and DGGE fingerprinting method for the analysis of specific rhizobial communities in soil.

    Science.gov (United States)

    de Oliveira, Valéria Maia; Manfio, Gilson Paulo; da Costa Coutinho, Heitor Luiz; Keijzer-Wolters, Anneke Christina; van Elsas, Jan Dirk

    2006-03-01

    A direct molecular method for assessing the diversity of specific populations of rhizobia in soil, based on nested PCR amplification of 16S-23S ribosomal RNA gene (rDNA) intergenic spacer (IGS) sequences, was developed. Initial generic amplification of bacterial rDNA IGS sequences from soil DNA was followed by specific amplification of (1) sequences affiliated with Rhizobium leguminosarum "sensu lato" and (2) R. tropici. Using analysis of the amplified sequences in clone libraries obtained on the basis of soil DNA, this two-sided method was shown to be very specific for rhizobial subpopulations in soil. It was then further validated as a direct fingerprinting tool of the target rhizobia based on denaturing gradient gel electrophoresis (DGGE). The PCR-DGGE approach was applied to soils from fields in Brazil cultivated with common bean (Phaseolus vulgaris) under conventional or no-tillage practices. The community fingerprints obtained allowed the direct analysis of the respective rhizobial community structures in soil samples from the two contrasting agricultural practices. Data obtained with both primer sets revealed clustering of the community structures of the target rhizobial types along treatment. Moreover, the DGGE profiles obtained with the R. tropici primer set indicated that the abundance and diversity of these organisms were favoured under NT practices. These results suggest that the R. leguminosarum-as well as R. tropici-targeted IGS-based nested PCR and DGGE are useful tools for monitoring the effect of agricultural practices on these and related rhizobial subpopulations in soils.

  12. Copy Number Variations in Candidate Genes and Intergenic Regions Affect Body Mass Index and Abdominal Obesity in Mexican Children

    Science.gov (United States)

    Burguete-García, Ana Isabel; Bonnefond, Amélie; Peralta-Romero, Jesús; Froguel, Philippe

    2017-01-01

    Introduction. Increase in body weight is a gradual process that usually begins in childhood and in adolescence as a result of multiple interactions among environmental and genetic factors. This study aimed to analyze the relationship between copy number variants (CNVs) in five genes and four intergenic regions with obesity in Mexican children. Methods. We studied 1423 children aged 6–12 years. Anthropometric measurements and blood levels of biochemical parameters were obtained. Identification of CNVs was performed by real-time PCR. The effect of CNVs on obesity or body composition was assessed using regression models adjusted for age, gender, and family history of obesity. Results. Gains in copy numbers of LEPR and NEGR1 were associated with decreased body mass index (BMI), waist circumference (WC), and risk of abdominal obesity, whereas gain in ARHGEF4 and CPXCR1 and the intergenic regions 12q15c, 15q21.1a, and 22q11.21d and losses in INS were associated with increased BMI and WC. Conclusion. Our results indicate a possible contribution of CNVs in LEPR, NEGR1, ARHGEF4, and CPXCR1 and the intergenic regions 12q15c, 15q21.1a, and 22q11.21d to the development of obesity, particularly abdominal obesity in Mexican children. PMID:28428959

  13. PairWise Neighbours database: overlaps and spacers among prokaryote genomes

    Directory of Open Access Journals (Sweden)

    Garcia-Vallvé Santiago

    2009-06-01

    Full Text Available Abstract Background Although prokaryotes live in a variety of habitats and possess different metabolic and genomic complexity, they have several genomic architectural features in common. The overlapping genes are a common feature of the prokaryote genomes. The overlapping lengths tend to be short because as the overlaps become longer they have more risk of deleterious mutations. The spacers between genes tend to be short too because of the tendency to reduce the non coding DNA among prokaryotes. However they must be long enough to maintain essential regulatory signals such as the Shine-Dalgarno (SD sequence, which is responsible of an efficient translation. Description PairWise Neighbours is an interactive and intuitive database used for retrieving information about the spacers and overlapping genes among bacterial and archaeal genomes. It contains 1,956,294 gene pairs from 678 fully sequenced prokaryote genomes and is freely available at the URL http://genomes.urv.cat/pwneigh. This database provides information about the overlaps and their conservation across species. Furthermore, it allows the wide analysis of the intergenic regions providing useful information such as the location and strength of the SD sequence. Conclusion There are experiments and bioinformatic analysis that rely on correct annotations of the initiation site. Therefore, a database that studies the overlaps and spacers among prokaryotes appears to be desirable. PairWise Neighbours database permits the reliability analysis of the overlapping structures and the study of the SD presence and location among the adjacent genes, which may help to check the annotation of the initiation sites.

  14. Molecular profiling of microbial communities from contaminated sources: Use of subtractive cloning methods and rDNA spacer sequences. 1998 annual progress report

    International Nuclear Information System (INIS)

    Robb, F.T.

    1998-01-01

    'The major objective of the research is to provide appropriate sequences and to assemble a high-density DNA array of oligonucleotides that can be used for rapid profiling of microbial populations from polluted areas. The sequences to be assigned to the DNA array are chosen from from cloned genomic DNA sequences (the ribosomal operon, described below) from groundwater at DOE sites containing organic solvents. The sites, Hanford Nuclear Plant and Lawrence Livermore Site 300, have well characterized pollutant histories, which have been provided by the collaborators. At this mid-point of the project, over 60 unique sequence classes of intergenic spacer region have been identified from the first sample site. The use of these sequences as hybridization probes, and their frequency of occurrence, allow a clear distinction between bacterial communities before and after remediation by acetate/nitrate pumping. The authors have developed the hybridization conditions for identifying PCR products in a 96 well format, a versatile alignment and visualization program (acronym: MALIGN) developed by Dr. Dennis Maeder, has been used to align the ISRs, which are variable in length and sometimes in position of the tRNAs. Finally, in collaboration with Dr. W. Chen and Dr. J. Zhou at ORNL, they have significant evidence that mass spectrometer analysis can be used to determine the lengths of PCR amplified intergenic spacer DNA.'

  15. Flow behavior of droplets downstream of the spacer

    International Nuclear Information System (INIS)

    Kodama, Eiichiro; Morishita, Kiyohide; Aritomi, Masanori; Yano, Takashi

    1998-01-01

    The fuel spacer, of which role is to maintain an appropriate rod-to-rod clearance, is one of the components of a Boiling Water Reactor (BWR) fuel rod bundles. The fuel spacer influences flow characteristics of the liquid film in fuel rod bundles, so that its geometry influences greatly thermal hydraulics such as critical power and pressure drop therein. The purpose of this study is to clarify the effect of the spacer geometry on the core flow split downstream of the spacer. Phase Doppler Anemometry (PDA) was used for their meausrement under the conditions of a small amount of droplets in mist flows. From the experimental results, the normalized droplet velocity profiles with a spacer were split by the spacer and were different between a wider and a narrower regions in the channel, however, they became uniform at the distance far 100mm from the spacer. In the case without a spacer, the velocity was monotonously increasing nearer the rod surface with going toward the center of the channel. In the case with a spacer, the velocity profile downstream of the spacer changed in the narrower region of the channel. This tendency became more remarkable with thickening the spacer and widening clearance between the spacer and the wall. In this paper, 'drift' velocity effect was applied for the spacer model, due to the gas flows were split by the spacer which is based on the momentum balance between the narrower and wider channels. This model was confirmed from the experimental results that the droplet flowed from a wider region to a narrower one. This drift effect appeared more strongly as the spacer became thicker and the clearance did narrower. The analytical results explained qualitatively the measured ones. It is clarified that the drift effect proposed in this work was a dominant factor on droplet deposition downstream of the spacer

  16. Symptomatic Citrus trees reveal a new pathogenic lineage in Fusarium and two new Neocosmospora species

    NARCIS (Netherlands)

    Sandoval-Denis, M.; Guarnaccia, V.; Polizzi, G.; Crous, P.W.

    2018-01-01

    The diversity of fusaria in symptomatic Citrus trees in Greece, Italy and Spain was evaluated using morphological and molecular multi-locus analyses based on fragments of the calmodulin (CAM), intergenic spacer region of the rDNA (IGS), internal transcribed spacer region of the rDNA (ITS), large

  17. Variability among the Most Rapidly Evolving Plastid Genomic Regions is Lineage-Specific: Implications of Pairwise Genome Comparisons in Pyrus (Rosaceae) and Other Angiosperms for Marker Choice

    Science.gov (United States)

    Ter-Voskanyan, Hasmik; Allgaier, Martin; Borsch, Thomas

    2014-01-01

    Plastid genomes exhibit different levels of variability in their sequences, depending on the respective kinds of genomic regions. Genes are usually more conserved while noncoding introns and spacers evolve at a faster pace. While a set of about thirty maximum variable noncoding genomic regions has been suggested to provide universally promising phylogenetic markers throughout angiosperms, applications often require several regions to be sequenced for many individuals. Our project aims to illuminate evolutionary relationships and species-limits in the genus Pyrus (Rosaceae)—a typical case with very low genetic distances between taxa. In this study, we have sequenced the plastid genome of Pyrus spinosa and aligned it to the already available P. pyrifolia sequence. The overall p-distance of the two Pyrus genomes was 0.00145. The intergenic spacers between ndhC–trnV, trnR–atpA, ndhF–rpl32, psbM–trnD, and trnQ–rps16 were the most variable regions, also comprising the highest total numbers of substitutions, indels and inversions (potentially informative characters). Our comparative analysis of further plastid genome pairs with similar low p-distances from Oenothera (representing another rosid), Olea (asterids) and Cymbidium (monocots) showed in each case a different ranking of genomic regions in terms of variability and potentially informative characters. Only two intergenic spacers (ndhF–rpl32 and trnK–rps16) were consistently found among the 30 top-ranked regions. We have mapped the occurrence of substitutions and microstructural mutations in the four genome pairs. High AT content in specific sequence elements seems to foster frequent mutations. We conclude that the variability among the fastest evolving plastid genomic regions is lineage-specific and thus cannot be precisely predicted across angiosperms. The often lineage-specific occurrence of stem-loop elements in the sequences of introns and spacers also governs lineage-specific mutations

  18. Variability among the most rapidly evolving plastid genomic regions is lineage-specific: implications of pairwise genome comparisons in Pyrus (Rosaceae and other angiosperms for marker choice.

    Directory of Open Access Journals (Sweden)

    Nadja Korotkova

    Full Text Available Plastid genomes exhibit different levels of variability in their sequences, depending on the respective kinds of genomic regions. Genes are usually more conserved while noncoding introns and spacers evolve at a faster pace. While a set of about thirty maximum variable noncoding genomic regions has been suggested to provide universally promising phylogenetic markers throughout angiosperms, applications often require several regions to be sequenced for many individuals. Our project aims to illuminate evolutionary relationships and species-limits in the genus Pyrus (Rosaceae-a typical case with very low genetic distances between taxa. In this study, we have sequenced the plastid genome of Pyrus spinosa and aligned it to the already available P. pyrifolia sequence. The overall p-distance of the two Pyrus genomes was 0.00145. The intergenic spacers between ndhC-trnV, trnR-atpA, ndhF-rpl32, psbM-trnD, and trnQ-rps16 were the most variable regions, also comprising the highest total numbers of substitutions, indels and inversions (potentially informative characters. Our comparative analysis of further plastid genome pairs with similar low p-distances from Oenothera (representing another rosid, Olea (asterids and Cymbidium (monocots showed in each case a different ranking of genomic regions in terms of variability and potentially informative characters. Only two intergenic spacers (ndhF-rpl32 and trnK-rps16 were consistently found among the 30 top-ranked regions. We have mapped the occurrence of substitutions and microstructural mutations in the four genome pairs. High AT content in specific sequence elements seems to foster frequent mutations. We conclude that the variability among the fastest evolving plastid genomic regions is lineage-specific and thus cannot be precisely predicted across angiosperms. The often lineage-specific occurrence of stem-loop elements in the sequences of introns and spacers also governs lineage-specific mutations. Sequencing

  19. Trypanosoma cruzi I genotypes in different geographic regions and transmission cycles based on a microsatellite motif of the intergenic spacer of spliced leader genes✯

    Science.gov (United States)

    Cura, Carolina I.; Mejía-Jaramillo, Ana M.; Duffy, Tomás; Burgos, Juan M.; Rodriguero, Marcela; Cardinal, Marta V.; Kjos, Sonia; Gurgel-Gonçalves, Rodrigo; Blanchet, Denis; De Pablos, Luis M.; Tomasini, Nicolás; Silva, Alex Da; Russomando, Graciela; Cuba Cuba, Cesar A.; Aznar, Christine; Abate, Teresa; Levin, Mariano J.; Osuna, Antonio; Gürtler, Ricardo E.; Diosque, Patricio; Solari, Aldo; Triana-Chávez, Omar; Schijman, Alejandro G.

    2011-01-01

    The intergenic region of spliced-leader (SL-IR) genes from 105 Trypanosoma cruzi I (Tc I) infected biological samples, culture isolates and stocks from 11 endemic countries, from Argentina to the USA were characterised, allowing identification of 76 genotypes with 54 polymorphic sites from 123 aligned sequences. On the basis of the microsatellite motif proposed by Herrera et al. (2007) to define four haplotypes in Colombia, we could classify these genotypes into four distinct Tc I SL-IR groups, three corresponding to the former haplotypes Ia (11 genotypes), Ib (11 genotypes) and Id (35 genotypes); and one novel group, Ie (19 genotypes). Genotypes harboring the Tc Ic motif were not detected in our study. Tc Ia was associated with domestic cycles in southern and northern South America and sylvatic cycles in Central and North America. Tc Ib was found in all transmission cycles from Colombia. Tc Id was identified in all transmission cycles from Argentina and Colombia, including Chagas cardiomyopathy patients, sylvatic Brazilian samples and human cases from French Guiana, Panama and Venezuela. Tc Ie gathered five samples from domestic Triatoma infestans from northern Argentina, nine samples from wild Mepraia spinolai and Mepraia gajardoi and two chagasic patients from Chile and one from a Bolivian patient with chagasic reactivation. Mixed infections by Tc Ia + Tc Id, Tc Ia + Tc Ie and Tc Id + Tc Ie were detected in vector faeces and isolates from human and vector samples. In addition, Tc Ia and Tc Id were identified in different tissues from a heart transplanted Chagas cardiomyopathy patient with reactivation, denoting histotropism. Trypanosoma cruzi I SL-IR genotypes from parasites infecting Triatoma gerstaeckeri and Didelphis virginiana from USA, T. infestans from Paraguay, Rhodnius nasutus and Rhodnius neglectus from Brazil and M. spinolai and M. gajardoi from Chile are to our knowledge described for the first time. PMID:20670628

  20. Local repeat sequence organization of an intergenic spacer

    Indian Academy of Sciences (India)

    The amplification yielded the same uniquely ``sequence-scrambled” product, whether the template used for PCR was total cellular DNA, chloroplast DNA or a plasmid clone DNA corresponding to that region. The PCR product, a ``unique” new sequence, had lost the repetitive organization of the template genome where it ...

  1. Phylogenetic relationships of the genus Phanerochaete inferred from the internal transcribed spacer region

    Science.gov (United States)

    Theodorus H. de Koker; Karen K. Nakasone; Jacques Haarhof; Harold H. Burdsall; Bernard J.H. Janse

    2003-01-01

    Phanerochaete is a genus of resupinate homobasidiomycetes that are saprophytic on woody debris and logs. Morphological studies in the past indicated that Phanerochaete is a heterogeneous assemblage of species. In this study the internal transcribed spacer (ITS) region of the nuclear ribosomal DNA was used to test the monophyly of the genus Phanerochaete and to infer...

  2. Comparison of automated ribosomal intergenic spacer analysis (ARISA) and denaturing gradient gel electrophoresis (DGGE) techniques for analysing the influence of diet on ruminal bacterial diversity.

    Science.gov (United States)

    Saro, Cristina; Molina-Alcaide, Eduarda; Abecia, Leticia; Ranilla, María José; Carro, María Dolores

    2018-04-01

    The objective of this study was to compare the automated ribosomal intergenic spacer analysis (ARISA) and the denaturing gradient gel electrophoresis (DGGE) techniques for analysing the effects of diet on diversity in bacterial pellets isolated from the liquid (liquid-associated bacteria (LAB)) and solid (solid-associated bacteria (SAB)) phase of the rumen. The four experimental diets contained forage to concentrate ratios of 70:30 or 30:70 and had either alfalfa hay or grass hay as forage. Four rumen-fistulated animals (two sheep and two goats) received the diets in a Latin square design. Bacterial pellets (LAB and SAB) were isolated at 2 h post-feeding for DNA extraction and analysed by ARISA and DGGE. The number of peaks in individual samples ranged from 48 to 99 for LAB and from 41 to 95 for SAB with ARISA, and values of DGGE-bands ranged from 27 to 50 for LAB and from 18 to 45 for SAB. The LAB samples from high concentrate-fed animals tended (p forage-fed animals with ARISA, but no differences were identified with DGGE. The SAB samples from high concentrate-fed animals had lower (p forage diets with ARISA, but only a trend was noticed for these parameters with DGGE (p forage type on LAB diversity was detected by any technique. In this study, ARISA detected some changes in ruminal bacterial communities that were not detected by DGGE, and therefore ARISA was considered more appropriate for assessing bacterial diversity of ruminal bacterial pellets. The results highlight the impact of the fingerprinting technique used to draw conclusions on dietary factors affecting bacterial diversity in ruminal bacterial pellets.

  3. Development and Validation of an Improved PCR Method Using the 23S-5S Intergenic Spacer for Detection of Rickettsiae in Dermacentor variabilis Ticks and Tissue Samples from Humans and Laboratory Animals.

    Science.gov (United States)

    Kakumanu, Madhavi L; Ponnusamy, Loganathan; Sutton, Haley T; Meshnick, Steven R; Nicholson, William L; Apperson, Charles S

    2016-04-01

    A novel nested PCR assay was developed to detectRickettsiaspp. in ticks and tissue samples from humans and laboratory animals. Primers were designed for the nested run to amplify a variable region of the 23S-5S intergenic spacer (IGS) ofRickettsiaspp. The newly designed primers were evaluated using genomic DNA from 11Rickettsiaspecies belonging to the spotted fever, typhus, and ancestral groups and, in parallel, compared to otherRickettsia-specific PCR targets (ompA,gltA, and the 17-kDa protein gene). The new 23S-5S IGS nested PCR assay amplified all 11Rickettsiaspp., but the assays employing other PCR targets did not. The novel nested assay was sensitive enough to detect one copy of a cloned 23S-5S IGS fragment from "CandidatusRickettsia amblyommii." Subsequently, the detection efficiency of the 23S-5S IGS nested assay was compared to those of the other three assays using genomic DNA extracted from 40 adultDermacentor variabilisticks. The nested 23S-5S IGS assay detectedRickettsiaDNA in 45% of the ticks, while the amplification rates of the other three assays ranged between 5 and 20%. The novel PCR assay was validated using clinical samples from humans and laboratory animals that were known to be infected with pathogenic species ofRickettsia The nested 23S-5S IGS PCR assay was coupled with reverse line blot hybridization with species-specific probes for high-throughput detection and simultaneous identification of the species ofRickettsiain the ticks. "CandidatusRickettsia amblyommii,"R. montanensis,R. felis, andR. belliiwere frequently identified species, along with some potentially novelRickettsiastrains that were closely related toR. belliiandR. conorii. Copyright © 2016 Kakumanu et al.

  4. Development and Validation of an Improved PCR Method Using the 23S-5S Intergenic Spacer for Detection of Rickettsiae in Dermacentor variabilis Ticks and Tissue Samples from Humans and Laboratory Animals

    Science.gov (United States)

    Kakumanu, Madhavi L.; Ponnusamy, Loganathan; Sutton, Haley T.; Meshnick, Steven R.; Nicholson, William L.

    2016-01-01

    A novel nested PCR assay was developed to detect Rickettsia spp. in ticks and tissue samples from humans and laboratory animals. Primers were designed for the nested run to amplify a variable region of the 23S-5S intergenic spacer (IGS) of Rickettsia spp. The newly designed primers were evaluated using genomic DNA from 11 Rickettsia species belonging to the spotted fever, typhus, and ancestral groups and, in parallel, compared to other Rickettsia-specific PCR targets (ompA, gltA, and the 17-kDa protein gene). The new 23S-5S IGS nested PCR assay amplified all 11 Rickettsia spp., but the assays employing other PCR targets did not. The novel nested assay was sensitive enough to detect one copy of a cloned 23S-5S IGS fragment from “Candidatus Rickettsia amblyommii.” Subsequently, the detection efficiency of the 23S-5S IGS nested assay was compared to those of the other three assays using genomic DNA extracted from 40 adult Dermacentor variabilis ticks. The nested 23S-5S IGS assay detected Rickettsia DNA in 45% of the ticks, while the amplification rates of the other three assays ranged between 5 and 20%. The novel PCR assay was validated using clinical samples from humans and laboratory animals that were known to be infected with pathogenic species of Rickettsia. The nested 23S-5S IGS PCR assay was coupled with reverse line blot hybridization with species-specific probes for high-throughput detection and simultaneous identification of the species of Rickettsia in the ticks. “Candidatus Rickettsia amblyommii,” R. montanensis, R. felis, and R. bellii were frequently identified species, along with some potentially novel Rickettsia strains that were closely related to R. bellii and R. conorii. PMID:26818674

  5. Differentiation of Populus species using chloroplast single nucleotide polymorphism (SNP) markers--essential for comprehensible and reliable poplar breeding.

    Science.gov (United States)

    Schroeder, H; Hoeltken, A M; Fladung, M

    2012-03-01

    Within the genus Populus several species belonging to different sections are cross-compatible. Hence, high numbers of interspecies hybrids occur naturally and, additionally, have been artificially produced in huge breeding programmes during the last 100 years. Therefore, determination of a single poplar species, used for the production of 'multi-species hybrids' is often difficult, and represents a great challenge for the use of molecular markers in species identification. Within this study, over 20 chloroplast regions, both intergenic spacers and coding regions, have been tested for their ability to differentiate different poplar species using 23 already published barcoding primer combinations and 17 newly designed primer combinations. About half of the published barcoding primers yielded amplification products, whereas the new primers designed on the basis of the total sequenced cpDNA genome of Populus trichocarpa Torr. & Gray yielded much higher amplification success. Intergenic spacers were found to be more variable than coding regions within the genus Populus. The highest discrimination power of Populus species was found in the combination of two intergenic spacers (trnG-psbK, psbK-psbl) and the coding region rpoC. In barcoding projects, the coding regions matK and rbcL are often recommended, but within the genus Populus they only show moderate variability and are not efficient in species discrimination. © 2011 German Botanical Society and The Royal Botanical Society of the Netherlands.

  6. Intra-Genomic Internal Transcribed Spacer Region Sequence Heterogeneity and Molecular Diagnosis in Clinical Microbiology.

    Science.gov (United States)

    Zhao, Ying; Tsang, Chi-Ching; Xiao, Meng; Cheng, Jingwei; Xu, Yingchun; Lau, Susanna K P; Woo, Patrick C Y

    2015-10-22

    Internal transcribed spacer region (ITS) sequencing is the most extensively used technology for accurate molecular identification of fungal pathogens in clinical microbiology laboratories. Intra-genomic ITS sequence heterogeneity, which makes fungal identification based on direct sequencing of PCR products difficult, has rarely been reported in pathogenic fungi. During the process of performing ITS sequencing on 71 yeast strains isolated from various clinical specimens, direct sequencing of the PCR products showed ambiguous sequences in six of them. After cloning the PCR products into plasmids for sequencing, interpretable sequencing electropherograms could be obtained. For each of the six isolates, 10-49 clones were selected for sequencing and two to seven intra-genomic ITS copies were detected. The identities of these six isolates were confirmed to be Candida glabrata (n=2), Pichia (Candida) norvegensis (n=2), Candida tropicalis (n=1) and Saccharomyces cerevisiae (n=1). Multiple sequence alignment revealed that one to four intra-genomic ITS polymorphic sites were present in the six isolates, and all these polymorphic sites were located in the ITS1 and/or ITS2 regions. We report and describe the first evidence of intra-genomic ITS sequence heterogeneity in four different pathogenic yeasts, which occurred exclusively in the ITS1 and ITS2 spacer regions for the six isolates in this study.

  7. RFLP of analyses of an intergenic spacer region of chloroplast DNA ...

    African Journals Online (AJOL)

    user

    2006-11-16

    Nov 16, 2006 ... amplified with PCR and digested with 6 restriction endonucleases (Hpa II, Alu I, Hinc II, Ava III, Nde I and. Hae III). According to results ... the environment, but DNA based techniques represent reliable tools and do not have many of ... existence of some variations in gene content (Downie and Palmer, 1992).

  8. RFLP of analyses of an intergenic spacer region of chloroplast DNA ...

    African Journals Online (AJOL)

    African Journal of Biotechnology. Journal Home · ABOUT ... In this study, 11 wheat species of Triticum and. Aegilops were ... and a phenogram was constructed using SAHN clustering unweighted pair group method using arithmetic averages.

  9. Genome-wide Anaplasma phagocytophilum AnkA-DNA interactions are enriched in intergenic regions and gene promoters and correlate with infection-induced differential gene expression.

    Directory of Open Access Journals (Sweden)

    J Stephen Dumler

    2016-09-01

    Full Text Available Anaplasma phagocytophilum, an obligate intracellular prokaryote, infects neutrophils and alters cardinal functions via reprogrammed transcription. Large contiguous regions of neutrophil chromosomes are differentially expressed during infection. Secreted A. phagocytophilum effector AnkA transits into the neutrophil or granulocyte nucleus to complex with DNA in heterochromatin across all chromosomes. AnkA binds to gene promoters to dampen cis-transcription and also has features of matrix attachment region (MAR-binding proteins that regulate three-dimensional chromatin architecture and coordinate transcriptional programs encoded in topologically-associated chromatin domains. We hypothesize that identification of additional AnkA binding sites will better delineate how A. phagocytophilum infection results in reprogramming of the neutrophil genome. Using AnkA-binding ChIP-seq, we showed that AnkA binds broadly throughout all chromosomes in a reproducible pattern, especially at: i intergenic regions predicted to be matrix attachment regions (MARs; ii within predicted lamina-associated domains; and iii at promoters ≤3,000 bp upstream of transcriptional start sites. These findings provide genome-wide support for AnkA as a regulator of cis-gene transcription. Moreover, the dominant mark of AnkA in distal intergenic regions known to be AT-enriched, coupled with frequent enrichment in the nuclear lamina, provides strong support for its role as a MAR-binding protein and genome re-organizer. AnkA must be considered a prime candidate to promote neutrophil reprogramming and subsequent functional changes that belie improved microbial fitness and pathogenicity.

  10. Molecular Profiling of Microbial Communities from Contaminated Sources: Use of Subtractive Cloning Methods and rDNA Spacer Sequences; FINAL

    International Nuclear Information System (INIS)

    Robb, Frank T.

    2001-01-01

    The major objective of this research was to provide appropriate sequences and assemble a DNA array of oligonucleotides to be used for rapid profiling of microbial populations from polluted areas and other areas of interest. The sequences to be assigned to the DNA array were chosen from cloned genomic DNA taken from groundwater sites having well characterized pollutant histories at Hanford Nuclear Plant and Lawrence Livermore Site 300. Glass-slide arrays were made and tested; and a new multiplexed, bead-based method was developed that uses nucleic acid hybridization on the surface of microscopic polystyrene spheres to identify specific sequences in heterogeneous mixtures of DNA sequences. The test data revealed considerable strain variation between sample sites showing a striking distribution of sequences. It also suggests that diversity varies greatly with bioremediation, and that there are many bacterial intergenic spacer region sequences that can indicate its effects. The bead method exhibited superior sequence discrimination and has features for easier and more accurate measurement

  11. Short communication: Identification of coagulase-negative staphylococcus species from goat milk with the API Staph identification test and with transfer RNA-intergenic spacer PCR combined with capillary electrophoresis.

    Science.gov (United States)

    Koop, G; De Visscher, A; Collar, C A; Bacon, D A C; Maga, E A; Murray, J D; Supré, K; De Vliegher, S; Haesebrouck, F; Rowe, J D; Nielen, M; van Werven, T

    2012-12-01

    Coagulase-negative staphylococci (CNS) are the most commonly isolated bacteria from goat milk, but they have often been identified with phenotypic methods, which may have resulted in misclassification. The aims of this paper were to assess the amount of misclassification of a phenotypic test for identifying CNS species from goat milk compared with transfer RNA intergenic spacer PCR (tDNA-PCR) followed by capillary electrophoresis, and to apply the tDNA-PCR technique on different capillary electrophoresis equipment. Milk samples were collected from 416 does in 5 Californian dairy goat herds on 3 occasions during lactation. In total, 219 CNS isolates were identified at the species level with tDNA-PCR and subjected to the API 20 Staph identification test kit (API Staph; bioMérieux, Durham, NC). If the same species was isolated multiple times from the same udder gland, only the first isolate was used for further analyses, resulting in 115 unique CNS isolates. According to the tDNA-PCR test, the most prevalent CNS species were Staphylococcus epidermidis, Staphylococcus caprae, and Staphylococcus simulans. Typeability with API staph was low (72%). Although the API Staph test was capable of identifying the majority of Staph. epidermidis and Staph. caprae isolates, sensitivity for identification of Staph. simulans was low. The true positive fraction was high for the 3 most prevalent species. It was concluded that the overall performance of API Staph in differentiating CNS species from goat milk was moderate to low, mainly because of the low typeability, and that genotypic methods such as tDNA-PCR are preferred. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  12. Analytical prediction of fuel assembly spacer grid loss coefficient

    International Nuclear Information System (INIS)

    Lim, J. S.; Nam, K. I.; Park, S. K.; Kwon, J. T.; Park, W. J.

    2002-01-01

    The analytical prediction model of the fuel assembly spacer grid pressure loss coefficient has been studied. The pressure loss of gap between the test section wall and spacer grid was separated from the current model and the different friction drag coefficient on spacer straps from high Reynolds number region were used to low Reynolds number region. The analytical model has been verified based on the hydraulic pressure drop test results for the spacer grids of three types for 5x5, 16x16(or 17x17) arrays. The analytical model predicts the pressure loss coefficients obtained from test results within the maximum errors of 12% and 7% for 5x5 test bundle and full size bundle, respectively, at Reynolds number 500,000 of the core operating condition. This result shows that the analytical model can be used for research and design change of the nuclear fuel assembly

  13. Intergenic and repeat transcription in human, chimpanzee and macaque brains measured by RNA-Seq.

    Directory of Open Access Journals (Sweden)

    Augix Guohua Xu

    Full Text Available Transcription is the first step connecting genetic information with an organism's phenotype. While expression of annotated genes in the human brain has been characterized extensively, our knowledge about the scope and the conservation of transcripts located outside of the known genes' boundaries is limited. Here, we use high-throughput transcriptome sequencing (RNA-Seq to characterize the total non-ribosomal transcriptome of human, chimpanzee, and rhesus macaque brain. In all species, only 20-28% of non-ribosomal transcripts correspond to annotated exons and 20-23% to introns. By contrast, transcripts originating within intronic and intergenic repetitive sequences constitute 40-48% of the total brain transcriptome. Notably, some repeat families show elevated transcription. In non-repetitive intergenic regions, we identify and characterize 1,093 distinct regions highly expressed in the human brain. These regions are conserved at the RNA expression level across primates studied and at the DNA sequence level across mammals. A large proportion of these transcripts (20% represents 3'UTR extensions of known genes and may play roles in alternative microRNA-directed regulation. Finally, we show that while transcriptome divergence between species increases with evolutionary time, intergenic transcripts show more expression differences among species and exons show less. Our results show that many yet uncharacterized evolutionary conserved transcripts exist in the human brain. Some of these transcripts may play roles in transcriptional regulation and contribute to evolution of human-specific phenotypic traits.

  14. 1 SHORT COMMUNICATION Resting behaviour of Anopheles ...

    African Journals Online (AJOL)

    2011-10-04

    Oct 4, 2011 ... Resting behaviour of Anopheles gambiae s.l. and its implication on malaria .... nature) were requested to sleep under the double mosquito net trap (one ... designed from the DNA sequences of the intergenic spacer region of ...

  15. Genetic diversity in breonadia salicina based on intra-species sequence variation of chloroplast dna spacer sequence

    International Nuclear Information System (INIS)

    Qurainy, F.A.; Gaafar, A.R.Z.

    2014-01-01

    Assessment and knowledge of the genetic diversity and variation within and between populations of rare and endangered plants is very important for effective conservation. Intergenic spacer sequences variation of psbA-trnH locus of chloroplast genome was assessed within Breonadia salicina (Rubiaceae), a critically endangered and endemic plant species to South western part of Kingdom of Saudi Arabia. The obtained sequence data from 19 individuals in three populations revealed nine haplotypes. The aligned sequences obtained from the overall Saudi accessions extended to 355 bp, revealing nine haplotypes. A high level of haplotype diversity (Hd = 0.842) and low level of nucleotide diversity (Pi = 0.0058) were detected. Consistently, both hierarchical analysis of molecular variance (AMOVA) and constructed neighbor-joining tree indicated null genetic differentiation among populations. This level of differentiation between populations or between regions in psbA-trnH sequences may be due to effects of the abundance of ancestral haplotype sharing and the presence of private haplotypes fixed for each population. Furthermore, the results revealed almost the same level of genetic diversity in comparison with Yemeni accessions, in which Saudi accessions were sharing three haplotypes from the four haplotypes found in Yemeni accessions. (author)

  16. A molecular diagnostic for tropical race 4 of the banana

    NARCIS (Netherlands)

    Dita Rodriguez, M.A.; Waalwijk, C.; Buddenhagen, I.W.; Souza, M.T.; Kema, G.H.J.

    2010-01-01

    This study analysed genomic variation of the translation elongation factor 1 (TEF-1) and the intergenic spacer region (IGS) of the nuclear ribosomal operon of Fusarium oxysporum f. sp. cubense (Foc) isolates, from different banana production areas, representing strains within the known races,

  17. New species in the genus Francisella (Gammaproteobacteria; Francisellaceae); Francisella piscicida sp. nov. isolated from cod (Gadus morhua)

    DEFF Research Database (Denmark)

    Ottem, Karl F; Nylund, Are; Karlsbakk, Egil

    2007-01-01

    A Francisella strain, GM2212, previously isolated from moribund farmed Atlantic cod (Gadus morhua) in Norway, is closely related to Francisella philomiragia among Francisella spp. according to its complete 16S rDNA, 16S-23S intergenic spacer, 23S rDNA, 23S-5S intergenic spacer, 5S rDNA, Fop...

  18. Employing 454 amplicon pyrosequencing to reveal intragenomic divergence in the internal transcribed spacer rDNA region in fungi

    Science.gov (United States)

    Daniel L. Lindner; Tor Carlsen; Henrik Nilsson; Marie Davey; Trond Schumacher; Havard. Kauserud

    2013-01-01

    The rDNA internal transcribed spacer (ITS) region has been accepted as a DNA barcoding marker for fungi and is widely used in phylogenetic studies; however, intragenomic ITS variability has been observed in a broad range of taxa, including prokaryotes, plants, animals, and fungi, and this variability has the potential to inflate species richness estimates in molecular...

  19. Preliminary analysis of the effect of the grid spacers on the reflood heat transfer

    International Nuclear Information System (INIS)

    Sugimoto, Jun; Murao, Yoshio

    1982-02-01

    The results are described about the preliminary analysis of the effect of the grid spacers on the heat transfer during reflood phase of a PWR LOCA. Experiments at JAERI and other facilities showed substantial heat transfer enhancement near the grid spacers. The heat transfer enhancement decreases with the distance from the grid spacers in the downstream region of the grid spacers. Several mechanisms are discussed about the heat transfer enhancement near the grid spacers. A model of a coalescence of the water droplets downstream the spacers is proposed based on the review of the experimental data. The heat transfer correlation for the saturated film boiling is utilized to quantify the heat transfer augmentation by the grid spacers. (author)

  20. Characterization of Francisella sp., GM2212, the first Francisella isolate from marine fish, Atlantic cod (Gadus morhua)

    DEFF Research Database (Denmark)

    Ottem, Karl F; Nylund, Are; Karlsbakk, Egil

    2007-01-01

    A Francisella sp., isolate GM2212(T), previously isolated from diseased farmed Atlantic cod Gadus morhua in Norway is characterized. The complete 16S rDNA, 16S-23S intergenic spacer, 23S rDNA, 23S-5S intergenic spacer, 5S rDNA, FopA, lipoprotein TUL4 (LpnA), malate dehydrogenase and a hypothetica...

  1. Inferring a role for methylation of intergenic DNA in the regulation of genes aberrantly expressed in precursor B-cell acute lymphoblastic leukemia.

    Science.gov (United States)

    Almamun, Md; Kholod, Olha; Stuckel, Alexei J; Levinson, Benjamin T; Johnson, Nathan T; Arthur, Gerald L; Davis, J Wade; Taylor, Kristen H

    2017-09-01

    A complete understanding of the mechanisms involved in the development of pre-B ALL is lacking. In this study, we integrated DNA methylation data and gene expression data to elucidate the impact of aberrant intergenic DNA methylation on gene expression in pre-B ALL. We found a subset of differentially methylated intergenic loci that were associated with altered gene expression in pre-B ALL patients. Notably, 84% of these regions were also bound by transcription factors (TF) known to play roles in differentiation and B-cell development in a lymphoblastoid cell line. Further, an overall downregulation of eRNA transcripts was observed in pre-B ALL patients and these transcripts were associated with the downregulation of putative target genes involved in B-cell migration, proliferation, and apoptosis. The identification of novel putative regulatory regions highlights the significance of intergenic DNA sequences and may contribute to the identification of new therapeutic targets for the treatment of pre-B ALL.

  2. Mixing vane grid spacer

    International Nuclear Information System (INIS)

    Patterson, J.F.; Galbraith, K.P.

    1978-01-01

    An improved mixing vane grid spacer having enhanced flow mixing capability by virtue of mixing vanes being positioned at welded intersecting joints of the spacer wherein each mixing vane has an opening or window formed therein substantially directly over the welded joint to provide improved flow mixing capability is described. Some of the vanes are slotted, depending on their particular location in the spacers. The intersecting joints are welded by initially providing consumable tabs at and within each window, which are consumed during the welding of the spacer joints

  3. Manipulation of recombination zone by utilizing the donor of electroplex as a spacer

    Energy Technology Data Exchange (ETDEWEB)

    Lü, Zhaoyue, E-mail: lvzhaoyue@ecust.edu.cn [Department of Physics, School of Science, East China University of Science & Technology, Shanghai 200237 (China); Yin, Yuehong [Department of Applied Physics, Institute of Physical Chemistry, Henan Polytechnic University, Jiaozuo, Henan Province 454000 (China); Xiao, Jing [Physics and Electronic Engineering College, Taishan University, Shandong Province 271021,China (China)

    2016-11-15

    The emission of electroplex is varied with applied voltages, leading to poor color stability of devices. In this work, the recombination region was investigated in organic light-emitting diodes (OLEDs) based on the electroplex between N,N’-diphenyl-N,N’-bis(1-naphthyl-phenyl)-1,1′-biphenyl-4,4′-diamine(NPB) and 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,2,4-oxadiazole (PBD). Color stability was manipulated by introducing the donor of electroplex as a spacer, which plays an important role of recombination zone for electroplex-based OLEDs. The 5-nm-spacer-device brought out a tolerable chromaticity coordinate shift of less than 0.01 for both x- and y-value. White light emission with CIE coordinates of (0.37,0.28) and (0.33,0.26) at 12 V was achieved when the thickness of spacer was 7 and 10 nm, respectively. The 7-nm-spacer-device exhibited better color stability than the 10-nm-spacer-device. This proves that adjusting spacer thickness is a simple and efficient method to control recombination region and can be useful for fulfilling color-stable electroplex-based white emission.

  4. Manipulation of recombination zone by utilizing the donor of electroplex as a spacer

    International Nuclear Information System (INIS)

    Lü, Zhaoyue; Yin, Yuehong; Xiao, Jing

    2016-01-01

    The emission of electroplex is varied with applied voltages, leading to poor color stability of devices. In this work, the recombination region was investigated in organic light-emitting diodes (OLEDs) based on the electroplex between N,N’-diphenyl-N,N’-bis(1-naphthyl-phenyl)-1,1′-biphenyl-4,4′-diamine(NPB) and 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,2,4-oxadiazole (PBD). Color stability was manipulated by introducing the donor of electroplex as a spacer, which plays an important role of recombination zone for electroplex-based OLEDs. The 5-nm-spacer-device brought out a tolerable chromaticity coordinate shift of less than 0.01 for both x- and y-value. White light emission with CIE coordinates of (0.37,0.28) and (0.33,0.26) at 12 V was achieved when the thickness of spacer was 7 and 10 nm, respectively. The 7-nm-spacer-device exhibited better color stability than the 10-nm-spacer-device. This proves that adjusting spacer thickness is a simple and efficient method to control recombination region and can be useful for fulfilling color-stable electroplex-based white emission.

  5. Potentials and limitations of histone repeat sequences for phylogenetic reconstruction of Sophophora.

    Science.gov (United States)

    Baldo, A M; Les, D H; Strausbaugh, L D

    1999-11-01

    Simplified DNA sequence acquisition has provided many new data sets that are useful for phylogenetic reconstruction, including single- and multiple-copy nuclear and organellar genes. Although transcribed regions receive much attention, nontranscribed regions have recently been added to the repertoire of sequences suitable for phylogenetic studies, especially for closely related taxa. We evaluated the efficacy of a small portion of the histone repeat for phylogenetic reconstruction among Drosophila species. Histone repeats in invertebrates offer distinct advantages similar to those of widely used ribosomal repeats. First, the units are tandemly repeated and undergo concerted evolution. Second, histone repeats include both highly conserved coding and variable intergenic regions. This composition facilitates application of "universal" primers spanning potentially informative sites. We examined a small region of the histone repeat, including the intergenic spacer segments of coding regions from the divergently transcribed H2A and H2B histone genes. The spacer (about 230 bp) exists as a mosaic with highly conserved functional motifs interspersed with rapidly diverging regions; the former aid in alignment of the spacer. There are no ambiguities in alignment of coding regions. Coding and noncoding regions were analyzed together and separately for phylogenetic information. Parsimony, distance, and maximum-likelihood methods successfully retrieve the corroborated phylogeny for the taxa examined. This study demonstrates the resolving power of a small histone region which may now be added to the growing collection of phylogenetically useful DNA sequences.

  6. Fouling resistant membrane spacers

    KAUST Repository

    Ghaffour, Noreddine

    2017-10-12

    Disclosed herein are spacers having baffle designs and perforations for efficiently and effectively separating one or more membrane layers a membrane filtration system. The spacer (504) includes a body (524) formed at least in part by baffles (520) that are interconnected, and the baffles define boundaries of openings or apertures (525) through a thickness direction of the body of the spacer. Alternatively or additionally, passages or perforations (526A, 526B) may be present in the spacer layer or baffles for fluid flow there through, with the passages and baffles having a numerous different shapes and sizes.

  7. Fuel spacer

    International Nuclear Information System (INIS)

    Nishida, Koji; Yokomizo, Osamu; Kanazawa, Toru; Kashiwai, Shin-ichi; Orii, Akihito.

    1992-01-01

    The present invention concerns a fuel spacer for a fuel assembly of a BWR type reactor and a PTR type reactor. Springs each having a vane are disposed on the side surface of a circular cell which supports a fuel rods. A vortex streams having a vertical component are formed by the vanes in the flowing direction of a flowing channel between adjacent cylindrical cells. Liquid droplets carried by streams are deposited on liquid membrane streams flowing along the fuel rod at the downstream of the spacer by the vortex streams. In view of the above, the liquid droplets can be deposited to the fuel rod without increasing the amount of metal of the spacer. Accordingly, the thermal margin of the fuel assembly can be improved without losing neutron economy. (I.N.)

  8. Structural Stator Spacers

    DEFF Research Database (Denmark)

    Rasmussen, Peter Omand; Andreasen, Jens H.; Pijanowski, J. M.

    2001-01-01

    This paper presents a powerful new design aspect to reduce acoustic noise and vibration of electro-magnetic origin for electrical machines, by introducing improved slot wedges referred to as "Structural Stator Spacers". These spacers, by using a very stiff dielectric and non magnetic material...

  9. Identification of Biomphalaria havanensis and Biomphalaria obstructa populations from Cuba using polymerase chain reaction and restriction fragment length polymorphism of the ribosomal RNA intergenic spacer

    Directory of Open Access Journals (Sweden)

    Teofânia HDA Vidigal

    2001-07-01

    Full Text Available In Cuba, several Biomphalaria species have been reported such as B. orbignyi, B. schrammi, B. helophila, B. havanensis and B. peregrina; only the latter three are considered as potential hosts of Schistosoma mansoni. The specific identification of Biomphalaria species is based on anatomical and morphological characters of genital organs and shells. The correct identification of these snails is complicated by the high variation in these characters, similarity among species and in some cases by the small size of the snails. In this paper, we reported the classical morphological identification, the use of PCR and RFLP analysis of the internal transcribed spacer region of the ribosomal RNA genes for molecular identification of seven snail populations from different localities in Cuba. Using morphological and molecular analysis, we showed that among the studied Cuban Biomphalaria populations only B. havanensis and B. obstructa species were found.

  10. Comparison of Fusarium oxysporum fsp lycopersici races 1, 2 and 3 ...

    African Journals Online (AJOL)

    Dr J. T. Ekanem

    Sequence analysis of genomic fragments from the intergenic spacer region from three isolates of. Fusarium oxysporum fsp lycoperisci and fsp radicis lycopersici was carried out using the big dye terminator sequencing procedure. Two conditions of the DNA templates were also evaluated for their influence on the outcome of ...

  11. IGS-RFLP analysis and development of molecular markers for identification of Fusarium poae, Fusarium langsethiae, Fusarium sporotrichioides and Fusarium kyushuense

    NARCIS (Netherlands)

    Konstantinova, P.S.; Yli-Mattila, T.

    2004-01-01

    The intergenic spacer (IGS) regions of the rDNA of several Fusarium spp. strains obtained from the collaborative researchers (Int. J. Food Microbiol. (2003)) were amplified by polymerase chain reaction (PCR), and an IGS¿RFLP analysis was performed. Restriction digestion with AluI, MspI and PstI

  12. Spacer device for nuclear reactor fuel elements

    International Nuclear Information System (INIS)

    Anthony, A.J.; Gaines, A.L.; Krawiec, D.M.

    1974-01-01

    The grid-type spacer device consists of two rows of main spacers arranged parallel to each other with some space in between, the first row extending perpendicular to the second row. Parallel to the respective rows of main spacers there are rows of secondary spacers interlocked with the main spacers. The individual spacers are welded together at their points of intersection. A large number of spring cages are installed within the spacer device to hold in place the main spacers which are oriented at right angles relative to each other. In addition, the spring cages serve for supporting the fuel elements. The spacers are made of zirconium which does not greatly influence the neutron capture cross section of the reactor. The material of the spring cages with the spring elements is a nickel alloy. It has the necessary stress relaxation properties to be able to force the fuel elements against the spacers under the action of the spring. (DG) [de

  13. Identification of Candida species by PCR and restriction fragment length polymorphism analysis of intergenic spacer regions of ribosomal DNA.

    OpenAIRE

    Williams, D W; Wilson, M J; Lewis, M A; Potts, A J

    1995-01-01

    The PCR was used to amplify a targeted region of the ribosomal DNA from 84 Candida isolates. Unique product sizes were obtained for Candida guilliermondii, Candida (Torulopsis) glabrata, and Candida pseudotropicalis. Isolates of Candida albicans, Candida tropicalis, Candida stellatoidea, Candida parapsilosis, and Candida krusei could be identified following restriction digestion of the PCR products.

  14. Nucleotide diversity and phylogenetic relationships among ...

    Indian Academy of Sciences (India)

    Navya

    2 attached at the base of tree as the diverging Iridaceae relative's lineage. Present study revealed that psbA-trnH region are useful in addressing questions of phylogenetic relationships among the Gladiolus cultivars, as these intergenic spacers are more variable and have more phylogenetically informative sites than the ...

  15. Spacer st4ructure

    International Nuclear Information System (INIS)

    Masetti, W.R.

    1978-01-01

    A spacer structure is described for maintaining a spaced relation between a plurality of generally parallel fuel rods within a housing in a nuclear reactor. The spacer structure is comprised of a grid pattern of ribs slotted to interlock with each other. The slots are arranged in such a way that when the ribs are welded to each other, the weld shrinkage is distributed uniformly in all directions to reduce or eliminate the amount of rework necessary in manufacturing the spacer structure

  16. Download this PDF file

    African Journals Online (AJOL)

    TonukariJ

    Fragment Length Polymorphism (PCR-RFLP) analysis of 16S-23S rDNA intergenic spacer region (IGS) directly applied on ... phylogenetic analysis of 16S rRNA gene sequences showed that they belong to the genus,. Bradyrhizobium. .... sterile water with plastic pestle sterilised in 96% ethanol in a 1,5-ml. Eppendorf tube.

  17. Numerical investigation on practicability of reducing MCST by using grid spacer in a tight rod bundle

    International Nuclear Information System (INIS)

    Zhu, Xiaojing; Morooka, Shinichi; Oka, Yoshiaki

    2014-01-01

    Highlights: • Standard grid spacer design causes decreased heat transfer in a tight rod bundle. • Heat transfer is greatly enhanced by flow-enhancing features. • Swirling flow adversely affects the heat transfer downstream of grid spacer. • Enhanced heat transfer by existing grid spacer is limited in a short region. • Improved grid spacer can effectively reduce MCST. - Abstract: The numerical investigation was carried out to reveal the practicability of reducing the maximum cladding surface temperature (MCST) within the inner sub-channel of a tight, hexagon rod bundle using commercial CFD code STAR CCM+ 6.04. The special heat transfer and pressure drop characteristics caused by four existing grid spacer designs were discussed in detail by analyzing the effects of grid strap length, different flow enhancing features and different Reynolds numbers. It was found that the local heat transfer within the grid strap is greatly enhanced due to the raised flow velocity. Both the standard grid spacer and the grid spacer with split-vanes cause decreased heat transfer in the downstream region. The friction drag is very influential in the tight rod bundle and can eliminate the positive effect of flow blockage on the heat transfer performance. The grid spacer with flow blockage discs induces relatively good heat transfer performance and higher pressure drop within sub-channels, indicating a tradeoff between the heat transfer augmentation and the pressure drop. The combination of multiple existing grid spacers can reduce the MCST to a certain level, but the corresponding disadvantages cannot be ignored. The improved grid spacer design was proposed based on the overall considerations of heat transfer and pressure drop characteristics and has been proved more suitable to widely reduce MCST for SCWR than any other grid spacer designs involved in present study

  18. Impact of underlap spacer region variation on electrostatic and analog performance of symmetrical high-k SOI FinFET at 20 nm channel length

    Science.gov (United States)

    Jain, Neeraj; Raj, Balwinder

    2017-12-01

    Continued scaling of CMOS technology to achieve high performance and low power consumption of semiconductor devices in the complex integrated circuits faces the degradation in terms of electrostatic integrity, short channel effects (SCEs), leakage currents, device variability and reliability etc. Nowadays, multigate structure has become the promising candidate to overcome these problems. SOI FinFET is one of the best multigate structures that has gained importance in all electronic design automation (EDA) industries due to its improved short channel effects (SCEs), because of its more effective gate-controlling capabilities. In this paper, our aim is to explore the sensitivity of underlap spacer region variation on the performance of SOI FinFET at 20 nm channel length. Electric field modulation is analyzed with spacer length variation and electrostatic performance is evaluated in terms of performance parameter like electron mobility, electric field, electric potential, sub-threshold slope (SS), ON current (I on), OFF current (I off) and I on/I off ratio. The potential benefits of SOI FinFET at drain-to-source voltage, V DS = 0.05 V and V DS = 0.7 V towards analog and RF design is also evaluated in terms of intrinsic gain (A V), output conductance (g d), trans-conductance (g m), gate capacitance (C gg), and cut-off frequency (f T = g m/2πC gg) with spacer region variations.

  19. Determination of locust bean gum and guar gum by polymerase chain reaction and restriction fragment length polymorphism analysis.

    Science.gov (United States)

    Meyer, K; Rosa, C; Hischenhuber, C; Meyer, R

    2001-01-01

    A polymerase chain reaction (PCR) was developed to differentiate the thickening agents locust bean gum (LBG) and the cheaper guar gum in finished food products. Universal primers for amplification of the intergenic spacer region between trnL 3' (UAA) exon and trnF (GAA) gene in the chloroplast (cp) genome and subsequent restriction analysis were applied to differentiate guar gum and LBG. The presence of guar gum powder added to LBG powder was detectable. Based on data obtained from sequencing this intergenic spacer region, a second PCR method for the specific detection of guar gum DNA was also developed. This assay detected guar gum powder in LBG in amounts as low as 1% (w/w). Both methods successfully detected guar gum and/or LBG in ice cream stabilizers and in foodstuffs, such as dairy products, ice cream, dry seasoning mixes, a finished roasting sauce, and a fruit jelly product, but not in products with highly degraded DNA, such as tomato ketchup and sterilized chocolate cream. Both methods detected guar gum and LBG in ice cream and fresh cheese at levels <0.1%.

  20. DNA barcode and identification of the varieties and provenances of Taiwan's domestic and imported made teas using ribosomal internal transcribed spacer 2 sequences.

    Science.gov (United States)

    Lee, Shih-Chieh; Wang, Chia-Hsiang; Yen, Cheng-En; Chang, Chieh

    2017-04-01

    The major aim of made tea identification is to identify the variety and provenance of the tea plant. The present experiment used 113 tea plants [Camellia sinensis (L.) O. Kuntze] housed at the Tea Research and Extension Substation, from which 113 internal transcribed spacer 2 (ITS2) fragments, 104 trnL intron, and 98 trnL-trnF intergenic sequence region DNA sequences were successfully sequenced. The similarity of the ITS2 nucleotide sequences between tea plants housed at the Tea Research and Extension Substation was 0.379-0.994. In this polymerase chain reaction-amplified noncoding region, no varieties possessed identical sequences. Compared with the trnL intron and trnL-trnF intergenic sequence fragments of chloroplast cpDNA, the proportion of ITS2 nucleotide sequence variation was large and is more suitable for establishing a DNA barcode database to identify tea plant varieties. After establishing the database, 30 imported teas and 35 domestic made teas were used in this model system to explore the feasibility of using ITS2 sequences to identify the varieties and provenances of made teas. A phylogenetic tree was constructed using ITS2 sequences with the unweighted pair group method with arithmetic mean, which indicated that the same variety of tea plant is likely to be successfully categorized into one cluster, but contamination from other tea plants was also detected. This result provides molecular evidence that the similarity between important tea varieties in Taiwan remains high. We suggest a direct, wide collection of made tea and original samples of tea plants to establish an ITS2 sequence molecular barcode identification database to identify the varieties and provenances of tea plants. The DNA barcode comparison method can satisfy the need for a rapid, low-cost, frontline differentiation of the large amount of made teas from Taiwan and abroad, and can provide molecular evidence of their varieties and provenances. Copyright © 2016. Published by Elsevier B.V.

  1. Pros and cons of symmetrical dual-k spacer technology in hybrid FinFETs

    Science.gov (United States)

    Pradhan, K. P.; Andrade, M. G. C.; Sahu, P. K.

    2016-12-01

    The symmetrical dual-k spacer technology in hybrid FinFETs has been widely explored for better electrostatic control of the fin-based devices in nanoscale region. Since, high-k tangible spacer materials are broadly became a matter of study due to their better immunity to the short channel effects (SCEs) in nano devices. However, the only cause that restricts the circuit designers from using high-k spacer is the unreasonable increasing fringing capacitances. This work quantitatively analyzed the benefits and drawbacks of considering two different dielectric spacer materials symmetrically in either sides of the channel for the hybrid device. From the demonstrated results, the inclusion of high-k spacer predicts an effective reduction in off-state leakage along with an improvement in drive current. However, these devices have paid the cost in terms of a high total gate-to-gate capacitance (Cgg) that consequently results poor cutoff frequency (fT) and delay.

  2. Fouling Resilient Perforated Feed Spacers for Membrane Filtration

    KAUST Repository

    Kerdi, Sarah

    2018-04-24

    The improvement of feed spacers with optimal geometry remains a key challenge for spiral-wound membrane systems in water treatment due to their impact on the hydrodynamic performance and fouling development. In this work, novel spacer designs are proposed by intrinsically modifying cylindrical filaments through perforations. Three symmetric perforated spacers (1-Hole, 2-Hole, and 3-Hole) were in-house 3D-printed and experimentally evaluated in terms of permeate flux, feed channel pressure drop and membrane fouling. Spacer performance is characterized and compared with standard no perforated (0-Hole) design under constant feed pressure and constant feed flow rate. Perforations in the spacer filaments resulted in significantly lowering the net pressure drop across the spacer filled channel. The 3-Hole spacer was found to have the lowest pressure drop (50% - 61%) compared to 0-Hole spacer for various average flow velocities. Regarding permeate flux production, the 0-Hole spacer produced 5.7 L.m-2.h-1 and 6.6 L.m-2.h-1 steady state flux for constant pressure and constant feed flow rate, respectively. The 1-Hole spacer was found to be the most efficient among the perforated spacers with 75% and 23% increase in permeate production at constant pressure and constant feed flow, respectively. Furthermore, membrane surface of 1-Hole spacer was found to be cleanest in terms of fouling, contributing to maintain higher permeate flux production. Hydrodynamic understanding of these perforated spacers is also quantified by performing Direct Numerical Simulation (DNS). The performance enhancement of these perforated spacers is attributed to the formation of micro-jets in the spacer cell that aided in producing enough unsteadiness/turbulence to clean the membrane surface and mitigate fouling phenomena. In the case of 1-Hole spacer, the unsteadiness intensity at the outlet of micro-jets and the shear stress fluctuations created inside the cells are higher than those observed with

  3. Fouling resilient perforated feed spacers for membrane filtration.

    Science.gov (United States)

    Kerdi, Sarah; Qamar, Adnan; Vrouwenvelder, Johannes S; Ghaffour, Noreddine

    2018-04-24

    The improvement of feed spacers with optimal geometry remains a key challenge for spiral-wound membrane systems in water treatment due to their impact on the hydrodynamic performance and fouling development. In this work, novel spacer designs are proposed by intrinsically modifying cylindrical filaments through perforations. Three symmetric perforated spacers (1-Hole, 2-Hole, and 3-Hole) were in-house 3D-printed and experimentally evaluated in terms of permeate flux, feed channel pressure drop and membrane fouling. Spacer performance is characterized and compared with standard no perforated (0-Hole) design under constant feed pressure and constant feed flow rate. Perforations in the spacer filaments resulted in significantly lowering the net pressure drop across the spacer filled channel. The 3-Hole spacer was found to have the lowest pressure drop (50%-61%) compared to 0-Hole spacer for various average flow velocities. Regarding permeate flux production, the 0-Hole spacer produced 5.7 L m -2 .h -1 and 6.6 L m -2 .h -1 steady state flux for constant pressure and constant feed flow rate, respectively. The 1-Hole spacer was found to be the most efficient among the perforated spacers with 75% and 23% increase in permeate production at constant pressure and constant feed flow, respectively. Furthermore, membrane surface of 1-Hole spacer was found to be cleanest in terms of fouling, contributing to maintain higher permeate flux production. Hydrodynamic understanding of these perforated spacers is also quantified by performing Direct Numerical Simulation (DNS). The performance enhancement of these perforated spacers is attributed to the formation of micro-jets in the spacer cell that aided in producing enough unsteadiness/turbulence to clean the membrane surface and mitigate fouling phenomena. In the case of 1-Hole spacer, the unsteadiness intensity at the outlet of micro-jets and the shear stress fluctuations created inside the cells are higher than those

  4. Development of a High Performance Spacer Grid

    Energy Technology Data Exchange (ETDEWEB)

    Song, Kee Nam; Song, K. N.; Yoon, K. H. (and others)

    2007-03-15

    A spacer grid in a LWR fuel assembly is a key structural component to support fuel rods and to enhance the heat transfer from the fuel rod to the coolant. In this research, the main research items are the development of inherent and high performance spacer grid shapes, the establishment of mechanical/structural analysis and test technology, and the set-up of basic test facilities for the spacer grid. The main research areas and results are as follows. 1. 18 different spacer grid candidates have been invented and applied for domestic and US patents. Among the candidates 16 are chosen from the patent. 2. Two kinds of spacer grids are finally selected for the advanced LWR fuel after detailed performance tests on the candidates and commercial spacer grids from a mechanical/structural point of view. According to the test results the features of the selected spacer grids are better than those of the commercial spacer grids. 3. Four kinds of basic test facilities are set up and the relevant test technologies are established. 4. Mechanical/structural analysis models and technology for spacer grid performance are developed and the analysis results are compared with the test results to enhance the reliability of the models.

  5. Spacer for supporting fuel element boxes

    International Nuclear Information System (INIS)

    Wild, E.

    1979-01-01

    A spacer plate unit arranged externally on each side and at a predetermined level of a polygonal fuel element box for mutually supporting, with respect to one another, a plurality of the fuel element boxes forming a fuel element bundle, is formed of a first and a second spacer plate part each having the same length and the same width and being constituted of unlike first and second materials, respectively. The first and second spacer plate parts of the several spacer plate units situated at the predetermined level are arranged in an alternating continuous series when viewed in the peripheral direction of the fuel element box, so that any two spacer plate units belonging to face-to-face oriented sides of two adjoining fuel element boxes in the fuel element bundle define interfaces of unlike materials

  6. Genomic relationships of Actinobacillus pleuropneumoniae serotype 2 strains evaluated by ribotyping, sequence analysis of ribosomal intergenic regions, and pulsed-field gel electrophoresis

    DEFF Research Database (Denmark)

    Fussing, V.

    1998-01-01

    The aim of the present study was to examine the genomic relationship among 112 Actinobacillus pleuropneumoniae serotype 2 strains obtained throughout Europe and North America. HindIII ribotyping of the strains resulted in five ribotypes of high similarity (87-98%). Sequence analysis of the riboso......The aim of the present study was to examine the genomic relationship among 112 Actinobacillus pleuropneumoniae serotype 2 strains obtained throughout Europe and North America. HindIII ribotyping of the strains resulted in five ribotypes of high similarity (87-98%). Sequence analysis...... of the ribosomal intergenic region of strains representing each ribotype and each country showed no differences. A common ribotype was further characterized by PFGE of 12 strains representing all countries. The resultant five PFGE patterns of European strains showed a similarity of more than 91%, to which the two...

  7. The independent loss model with ordered insertions for the evolution of CRISPR spacers.

    Science.gov (United States)

    Baumdicker, F; Huebner, A M I; Pfaffelhuber, P

    2018-02-01

    Today, the CRISPR (clustered regularly interspaced short palindromic repeats) region within bacterial and archaeal genomes is known to encode an adaptive immune system. We rely on previous results on the evolution of the CRISPR arrays, which led to the ordered independent loss model, introduced by Kupczok and Bollback (2013). When focusing on the spacers (between the repeats), new elements enter a CRISPR array at rate θ at the leader end of the array, while all spacers present are lost at rate ρ along the phylogeny relating the sample. Within this model, we compute the distribution of distances of spacers which are present in all arrays in a sample of size n. We use these results to estimate the loss rate ρ from spacer array data for n=2 and n=3. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. The High Degree of Sequence Plasticity of the Arenavirus Noncoding Intergenic Region (IGR) Enables the Use of a Nonviral Universal Synthetic IGR To Attenuate Arenaviruses.

    Science.gov (United States)

    Iwasaki, Masaharu; Cubitt, Beatrice; Sullivan, Brian M; de la Torre, Juan C

    2016-01-06

    Hemorrhagic fever arenaviruses (HFAs) pose important public health problems in regions where they are endemic. Concerns about human-pathogenic arenaviruses are exacerbated because of the lack of FDA-licensed arenavirus vaccines and because current antiarenaviral therapy is limited to an off-label use of ribavirin that is only partially effective. We have recently shown that the noncoding intergenic region (IGR) present in each arenavirus genome segment, the S and L segments (S-IGR and L-IGR, respectively), plays important roles in the control of virus protein expression and that this knowledge could be harnessed for the development of live-attenuated vaccine strains to combat HFAs. In this study, we further investigated the sequence plasticity of the arenavirus IGR. We demonstrate that recombinants of the prototypic arenavirus lymphocytic choriomeningitis virus (rLCMVs), whose S-IGRs were replaced by the S-IGR of Lassa virus (LASV) or an entirely nonviral S-IGR-like sequence (Ssyn), are viable, indicating that the function of S-IGR tolerates a high degree of sequence plasticity. In addition, rLCMVs whose L-IGRs were replaced by Ssyn or S-IGRs of the very distantly related reptarenavirus Golden Gate virus (GGV) were viable and severely attenuated in vivo but able to elicit protective immunity against a lethal challenge with wild-type LCMV. Our findings indicate that replacement of L-IGR by a nonviral Ssyn could serve as a universal molecular determinant of arenavirus attenuation. Hemorrhagic fever arenaviruses (HFAs) cause high rates of morbidity and mortality and pose important public health problems in regions where they are endemic. Implementation of live-attenuated vaccines (LAVs) will represent a major step to combat HFAs. Here we document that the arenavirus noncoding intergenic region (IGR) has a high degree of plasticity compatible with virus viability. This observation led us to generate recombinant LCMVs containing nonviral synthetic IGRs. These r

  9. Molecular detection of toxigenic potential of fungi in peanut samples collected in retail shops in Maringá/PR, Brazil

    Directory of Open Access Journals (Sweden)

    Alessandra Valéria de Oliveira

    2015-02-01

    Full Text Available Many foods are susceptible to fungal contamination. Grains, such as peanuts, are commonly affected, with consequences including compromised integrity and infeasibility for human and animal consumption. Furthermore, some fungi may pose a health risk, largely due the production of mycotoxins. Among these, aflatoxins produced by Aspergillus flavus and A. parasiticus produce various carcinogenic, teratogenic, immunosuppressive, hepatotoxic and nephrotoxic effects. Molecular techniques have been used to identify and distinguish fungal species in foods. The objective of this study was molecular detection of Aspergillus species in peanut samples collected in stores in Maringá-PR, by amplification of fungal genetic material with specific primers for the intergenic spacer aflR-aflJ and later cutting with restriction enzymes. Of the 50 peanut samples analyzed, 27 were positive for the intergenic spacer aflR-aflJ, seven of which were identified as Aspergillus flavus. Our results demonstrate that peanuts sold in retail stores in this region have potential for contamination with toxigenic fungi.

  10. Side insertable spacer

    International Nuclear Information System (INIS)

    Patterson, J.F.; Ewing, R.H.

    1992-01-01

    This patent describes a spacer for restraining the fuel rods of a nuclear fuel assembly, the assembly being formed of a plurality of parallel, elongated fuel rods so arranged that the assembly is bounded by a polygon having an even number of sides, the rods being so arranged as to lie in a plurality of sets of parallel rows, the rows of each set being perpendicular to one of the sides of the polygon. It comprises a number of spacer combs equal to at least half the number of the sides of the polygon, the spacer combs being superposed on each other, each of the spacer combs comprising: a single base strip having a length equal to that of one of the sides of the polygon and grid strips equal in number to the spaces between rows in one of the sets, and at least a majority of the grid strips being of a length sufficient to extend substantially the full length of the rows; the grid strips being provided with spring members positioned to engage each of the rods; the grid strips being provided with spring members positioned to engage each of the rods; the grid strips being secured to and extending at right angles to the base strip; the grid strips of different combs being positioned at angles to each other, so as to occupy the spaces between rows in different sets

  11. Fouling Resilient Perforated Feed Spacers for Membrane Filtration

    KAUST Repository

    Kerdi, Sarah; Qamar, Adnan; Vrouwenvelder, Johannes S.; Ghaffour, NorEddine

    2018-01-01

    drop across the spacer filled channel. The 3-Hole spacer was found to have the lowest pressure drop (50% - 61%) compared to 0-Hole spacer for various average flow velocities. Regarding permeate flux production, the 0-Hole spacer produced 5.7 L.m-2.h-1

  12. Antibiotic impregnated total femur spacers: a technical tip

    Directory of Open Access Journals (Sweden)

    Colin D. Canham, MD

    2018-03-01

    Full Text Available Simultaneous prosthetic joint infection of ipsilateral hip and knee arthroplasties is often accompanied by significant bone loss and presents a challenging reconstructive problem. Two-stage reconstruction is favored and requires the placement of a total femur spacer, which is not a commercially available device. We describe a surgical technique, reporting on 2 cases in which a customized total femur antibiotic impregnated spacer was created by combining an articulating knee spacer and an articulating hip spacer with a reinforced cement dowel construct connecting the 2 spacers. Custom total femoral spacers are useful in the management of infected femoral megaprostheses and cases with ipsilateral injected hip and knee arthroplasties and severe femoral bone loss. Keywords: total femur spacer, revision arthroplasty, total hip arthroplasty, total knee arthroplasty, prosthetic joint infection

  13. Chromosome-wide mapping of DNA methylation patterns in normal and malignant prostate cells reveals pervasive methylation of gene-associated and conserved intergenic sequences

    Directory of Open Access Journals (Sweden)

    De Marzo Angelo M

    2011-06-01

    Full Text Available Abstract Background DNA methylation has been linked to genome regulation and dysregulation in health and disease respectively, and methods for characterizing genomic DNA methylation patterns are rapidly emerging. We have developed/refined methods for enrichment of methylated genomic fragments using the methyl-binding domain of the human MBD2 protein (MBD2-MBD followed by analysis with high-density tiling microarrays. This MBD-chip approach was used to characterize DNA methylation patterns across all non-repetitive sequences of human chromosomes 21 and 22 at high-resolution in normal and malignant prostate cells. Results Examining this data using computational methods that were designed specifically for DNA methylation tiling array data revealed widespread methylation of both gene promoter and non-promoter regions in cancer and normal cells. In addition to identifying several novel cancer hypermethylated 5' gene upstream regions that mediated epigenetic gene silencing, we also found several hypermethylated 3' gene downstream, intragenic and intergenic regions. The hypermethylated intragenic regions were highly enriched for overlap with intron-exon boundaries, suggesting a possible role in regulation of alternative transcriptional start sites, exon usage and/or splicing. The hypermethylated intergenic regions showed significant enrichment for conservation across vertebrate species. A sampling of these newly identified promoter (ADAMTS1 and SCARF2 genes and non-promoter (downstream or within DSCR9, C21orf57 and HLCS genes hypermethylated regions were effective in distinguishing malignant from normal prostate tissues and/or cell lines. Conclusions Comparison of chromosome-wide DNA methylation patterns in normal and malignant prostate cells revealed significant methylation of gene-proximal and conserved intergenic sequences. Such analyses can be easily extended for genome-wide methylation analysis in health and disease.

  14. The Intergenic Recombinant HLA-B*46:01 Has a Distinctive Peptidome that Includes KIR2DL3 Ligands

    DEFF Research Database (Denmark)

    Hilton, Hugo G.; McMurtrey, Curtis P.; Han, Alex S.

    2017-01-01

    HLA-B*46:01 was formed by an intergenic mini-conversion, between HLA-B*15:01 and HLA-C*01:02, in Southeast Asia during the last 50,000 years, and it has since become the most common HLA-B allele in the region. A functional effect of the mini-conversion was introduction of the C1 epitope into HLA-...

  15. Bacteremia with the bovis group streptococci

    DEFF Research Database (Denmark)

    Marmolin, Ea S; Hartmeyer, Gitte N; Christensen, Jens Jørgen

    2016-01-01

    DNA sequencing of the intergenic spacer (ITS) region was used to identify 53 blood culture isolates that had previously been designated to the bovis group streptococci and clinical data was collected retrospectively from patients' records using a standardized protocol. ITS sequencing identified 19....... pasteurianus (58.7%) bacteremia calls for intensive investigation for underlying disease focusing on the pancreas and the hepatobiliary system....

  16. Lower end fitting debris collector and end cap spacer grid

    International Nuclear Information System (INIS)

    Bryan, W.J.

    1990-01-01

    This patent describes a nuclear reactor having fuel assemblies including an upper end fitting and spaced nuclear fuel rod spacer grids for supporting and spacing a plurality of elongated nuclear fuel rods. Each includes a hollow active portion of nuclear fuel filled cladding intermediate the rod ends and tapering end cap of solid material with a circumferential groove on the rod end which first encounters reactor coolant flow, a lower end filtering debris collector and end cap spacer grid for capturing and retaining deleterious debris carried by reactor coolant before it enters the active region of a fuel assembly and creates fuel rod cladding damage

  17. Genotyping of human lice suggests multiple emergencies of body lice from local head louse populations.

    Directory of Open Access Journals (Sweden)

    Wenjun Li

    Full Text Available BACKGROUND: Genetic analyses of human lice have shown that the current taxonomic classification of head lice (Pediculus humanus capitis and body lice (Pediculus humanus humanus does not reflect their phylogenetic organization. Three phylotypes of head lice A, B and C exist but body lice have been observed only in phylotype A. Head and body lice have different behaviours and only the latter have been involved in outbreaks of infectious diseases including epidemic typhus, trench fever and louse borne recurrent fever. Recent studies suggest that body lice arose several times from head louse populations. METHODS AND FINDINGS: By introducing a new genotyping technique, sequencing variable intergenic spacers which were selected from louse genomic sequence, we were able to evaluate the genotypic distribution of 207 human lice. Sequence variation of two intergenic spacers, S2 and S5, discriminated the 207 lice into 148 genotypes and sequence variation of another two intergenic spacers, PM1 and PM2, discriminated 174 lice into 77 genotypes. Concatenation of the four intergenic spacers discriminated a panel of 97 lice into 96 genotypes. These intergenic spacer sequence types were relatively specific geographically, and enabled us to identify two clusters in France, one cluster in Central Africa (where a large body louse outbreak has been observed and one cluster in Russia. Interestingly, head and body lice were not genetically differentiated. CONCLUSIONS: We propose a hypothesis for the emergence of body lice, and suggest that humans with both low hygiene and head louse infestations provide an opportunity for head louse variants, able to ingest a larger blood meal (a required characteristic of body lice, to colonize clothing. If this hypothesis is ultimately supported, it would help to explain why poor human hygiene often coincides with outbreaks of body lice. Additionally, if head lice act as a reservoir for body lice, and that any social degradation in

  18. Pressure Drop Test of Hybrid Mixing Vane Spacer Grid

    Energy Technology Data Exchange (ETDEWEB)

    Oh, D. S.; Chang, S. K.; Kim, B. D.; Chun, S. Y.; Chun, T. H

    2007-08-15

    The pressure loss test has been accomplished in the test section containing 5x5 rod bundle with a length of 2 m including 3 spacer grids. The test has been performed for the 5 kinds of spacer grids to compare the pressure loss characteristics: 1. Plain spacer grid which has the same body of the Hybrid but without vane (Plain), 2. Hybrid Vane spacer grid (Hybrid), 3. Hybrid-SC spacer grid which is constructed with coined, chamfered strip and is fabricated by spot welding, 4. Hybrid-LC spacer grid which is constructed with coined, chamfered strip and is fabricated by line welding along intersection line, 5. Westinghouse spacer grid with split vane (Plus-7). The pressure loss coefficient of the Plain, Hybrid, Hybrid-SC, Hybrid-LC, and Plus-7 spacer grid is 0.93, 1.15, 1.02, 1.04, and 1.08, respectively.

  19. Nuclear ribosomal internal transcribed spacer (ITS) region as a universal DNA barcode marker for Fungi.

    Science.gov (United States)

    Schoch, Conrad L; Seifert, Keith A; Huhndorf, Sabine; Robert, Vincent; Spouge, John L; Levesque, C André; Chen, Wen

    2012-04-17

    Six DNA regions were evaluated as potential DNA barcodes for Fungi, the second largest kingdom of eukaryotic life, by a multinational, multilaboratory consortium. The region of the mitochondrial cytochrome c oxidase subunit 1 used as the animal barcode was excluded as a potential marker, because it is difficult to amplify in fungi, often includes large introns, and can be insufficiently variable. Three subunits from the nuclear ribosomal RNA cistron were compared together with regions of three representative protein-coding genes (largest subunit of RNA polymerase II, second largest subunit of RNA polymerase II, and minichromosome maintenance protein). Although the protein-coding gene regions often had a higher percent of correct identification compared with ribosomal markers, low PCR amplification and sequencing success eliminated them as candidates for a universal fungal barcode. Among the regions of the ribosomal cistron, the internal transcribed spacer (ITS) region has the highest probability of successful identification for the broadest range of fungi, with the most clearly defined barcode gap between inter- and intraspecific variation. The nuclear ribosomal large subunit, a popular phylogenetic marker in certain groups, had superior species resolution in some taxonomic groups, such as the early diverging lineages and the ascomycete yeasts, but was otherwise slightly inferior to the ITS. The nuclear ribosomal small subunit has poor species-level resolution in fungi. ITS will be formally proposed for adoption as the primary fungal barcode marker to the Consortium for the Barcode of Life, with the possibility that supplementary barcodes may be developed for particular narrowly circumscribed taxonomic groups.

  20. A study on improvement of analytical prediction model for spacer grid pressure loss coefficients

    International Nuclear Information System (INIS)

    Lim, Jonh Seon

    2002-02-01

    Nuclear fuel assemblies used in the nuclear power plants consist of the nuclear fuel rods, the control rod guide tubes, an instrument guide tube, spacer grids,a bottom nozzle, a top nozzle. The spacer grid is the most important component of the fuel assembly components for thermal hydraulic and mechanical design and analyses. The spacer grids fixed with the guide tubes support the fuel rods and have the very important role to activate thermal energy transfer by the coolant mixing caused to the turbulent flow and crossflow in the subchannels. In this paper, the analytical spacer grid pressure loss prediction model has been studied and improved by considering the test section wall to spacer grid gap pressure loss independently and applying the appropriate friction drag coefficient to predict pressure loss more accurately at the low Reynolds number region. The improved analytical model has been verified based on the hydraulic pressure drop test results for the spacer grids of three types with 5x5, 16x16, 17x17 arrays, respectively. The pressure loss coefficients predicted by the improved analytical model are coincident with those test results within ±12%. This result shows that the improved analytical model can be used for research and design change of the nuclear fuel assembly

  1. Comparative studies of 111In-labeled monoclonal antibody using spacer-containing and non-spacer bifunctional chelates. 2

    International Nuclear Information System (INIS)

    Sun, Baofu

    1994-01-01

    Indium-111-labeled A7 monoclonal antibodies using two spacer-containing chelates, succinimido-EGS-DTPA (EGS-DTPA: diester spacer) and maleimido-C10-Bz-EDTA (C10-Bz-EDTA: hydrocarbon spacer) were investigated in human LS180 colon tumor bearing nude mice and were compared with two non-spacer chelates, cyclic DTPA dianhydride (cDTPAA) and isothiocyanatobenzyl-EDTA (SCN-Bz-EDTA). Compared with immunoconjugates using non-spacer chelates, immunoconjugates using spacer-containing chelates, especially C10-Bz-EDTA-A7 showed lower 111 In activity in normal organs. The radioactivity in the liver for C10-Bz-EDTA-A7 decreased continuously till 96 hrs postinjection, however, this liver radioactivity for EGS-DTPA-A7 showed little change after 24 hrs. Moreover, in liver subcellular distribution study, EGS-DTPA-A7 showed a higher activity retention in mitochondrial fraction which contained lysosome, a place for metabolizing and storing of 111 In labeled antibody, than that of C10-Bz-EDTA-A7. The C10-Bz-EDTA-A7 conjugate demonstrated more preferable tumor-to-non tumor contrast on the scintigrams than that found with other three immunoconjugates. Up to 96 hrs postinjection, tumor bearing nude mice injecting with immunoconjugates using spacer-containing chelates exreted twice radioactivity from whole body than that excreted by using non-spacer chelates. Interestingly, different from other three chelates, C10-Bz-EDTA-A7 were mainly excreted via feces. We conclude that the decrease of radioactivity in normal tissues in the case of EGS-DTPA-A7 was due to the rapid decrease of activity in the blood, while in the case of C10-Bz-EDTA-A7 it was due to the quickly excreted small metabolite through faces. 111 In labeled C10-Bz-EDTA conjugate is superior, at least when conjugated with A7, to other three chelate conjugates used in this study. (author)

  2. Pressure Drop of Chamfer on Spacer Grid Strap

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Euijae; Kim, Kanghoon; Kim, Kyounghong; Nahm, Keeyil [KEPCO Nuclear Fuel Co., Daejeon (Korea, Republic of)

    2014-05-15

    A swirl flow and cross flow are generated by the spacer grid with mixing vane that enhances the thermal performance and critical heat flux (CHF). The additional pressure drop makes it difficult to meet acceptance criteria for overall pressure drop in fuel assembly depending upon the pump capacity. The chamfer on the end of spacer grid strap is one solution to reduce additional pressure drop without any adverse effect on flow fields. In this research, the pressure drop tests for spacer grid with and without chamfer were carried out at the hydraulic test facility. The result can be applied to develop high performance nuclear fuel assemblies for Pressurized Water Reactor (PWR) plants. The pressure drop tests for 5x5 spacer grid with and without chamfer as well as 6x6 spacer grid with and without chamfer were carried out at the INFINIT test facility. The Reynolds number ranged about from 16000 to 75000. The sweep-up and sweep-down test showed that the direction of sweep did not affect the pressure drop. The chamfer on spacer grid strap reduced the pressure drop due to the decreased in ratio of inlet area to outlet area. The pressure loss coefficient for spacer grid with chamfer was by up to 13.8 % lower than that for spacer grid without chamfer. Hence, the chamfer on spacer grid strap was one of effective ways to reduce the pressure drop.

  3. Rapid and accurate identification of isolates of Candida species by melting peak and melting curve analysis of the internally transcribed spacer region 2 fragment (ITS2-MCA)

    NARCIS (Netherlands)

    Decat, E.; van Mechelen, E.; Saerens, B.; Vermeulen, S.J.T.; Boekhout, T.; de Blaiser, S.; Vaneechoutte, M.; Deschaght, P.

    2013-01-01

    Rapid identification of clinically important yeasts can facilitate the initiation of anti-fungal therapy, since susceptibility is largely species-dependent. We evaluated melting peak and melting curve analysis of the internally transcribed spacer region 2 fragment (ITS2-MCA) as an identification

  4. Identification and characterization of long intergenic noncoding RNAs in bovine mammary glands.

    Science.gov (United States)

    Tong, Chao; Chen, Qiaoling; Zhao, Lili; Ma, Junfei; Ibeagha-Awemu, Eveline M; Zhao, Xin

    2017-06-19

    Mammary glands of dairy cattle produce milk for the newborn offspring and for human consumption. Long intergenic noncoding RNAs (lincRNAs) play various functions in eukaryotic cells. However, types and roles of lincRNAs in bovine mammary glands are still poorly understood. Using computational methods, 886 unknown intergenic transcripts (UITs) were identified from five RNA-seq datasets from bovine mammary glands. Their non-coding potentials were predicted by using the combination of four software programs (CPAT, CNCI, CPC and hmmscan), with 184 lincRNAs identified. By comparison to the NONCODE2016 database and a domestic-animal long noncoding RNA database (ALDB), 112 novel lincRNAs were revealed in bovine mammary glands. Many lincRNAs were found to be located in quantitative trait loci (QTL). In particular, 36 lincRNAs were found in 172 milk related QTLs, whereas one lincRNA was within clinical mastitis QTL region. In addition, targeted genes for 10 lincRNAs with the highest fragments per kilobase of transcript per million fragments mapped (FPKM) were predicted by LncTar for forecasting potential biological functions of these lincRNAs. Further analyses indicate involvement of lincRNAs in several biological functions and different pathways. Our study has provided a panoramic view of lincRNAs in bovine mammary glands and suggested their involvement in many biological functions including susceptibility to clinical mastitis as well as milk quality and production. This integrative annotation of mammary gland lincRNAs broadens and deepens our understanding of bovine mammary gland biology.

  5. The potential of standard and modified feed spacers for biofouling control

    KAUST Repository

    Araú jo, Paula A.; Kruithof, Joop C.; van Loosdrecht, Mark C.M.; Vrouwenvelder, Johannes S.

    2012-01-01

    The impact of feed spacers on initial feed channel pressure (FCP) drop, FCP increase and biomass accumulation has been studied in membrane fouling simulators using feed spacers applied in commercially available nanofiltration and reverse osmosis spiral wound membrane modules. All spacers had a similar geometry.Our studies showed that biofouling was not prevented by (i) variation of spacer thickness, (ii) feed spacer orientation, (iii) feed spacer coating with silver, copper or gold and (iv) using a biostatic feed spacer. At constant feed flow, a lower FCP and FCP increase were observed for a thicker feed spacer. At constant linear flow velocity, roughly the same FCP development and biomass accumulation were found irrespective of the feed spacer thickness: hydrodynamics and substrate load were more important for development and impact of biofouling than the thickness of currently applied spacers. Use of biostatic and metal coated spacers were not effective for biofouling control. The same small reduction of biofouling rate was observed with copper and silver coated spacers as well as uncoated 45° rotated spacers.The studied modified spacers were not effective for biofouling prevention and control. The impact of biofouling on FCP increase was reduced significantly by a lower linear flow velocity, while spacer orientation and spacer thickness in membrane modules had a smaller but still significant effect. © 2012 Elsevier B.V.

  6. The potential of standard and modified feed spacers for biofouling control

    KAUST Repository

    Araújo, Paula A.

    2012-06-01

    The impact of feed spacers on initial feed channel pressure (FCP) drop, FCP increase and biomass accumulation has been studied in membrane fouling simulators using feed spacers applied in commercially available nanofiltration and reverse osmosis spiral wound membrane modules. All spacers had a similar geometry.Our studies showed that biofouling was not prevented by (i) variation of spacer thickness, (ii) feed spacer orientation, (iii) feed spacer coating with silver, copper or gold and (iv) using a biostatic feed spacer. At constant feed flow, a lower FCP and FCP increase were observed for a thicker feed spacer. At constant linear flow velocity, roughly the same FCP development and biomass accumulation were found irrespective of the feed spacer thickness: hydrodynamics and substrate load were more important for development and impact of biofouling than the thickness of currently applied spacers. Use of biostatic and metal coated spacers were not effective for biofouling control. The same small reduction of biofouling rate was observed with copper and silver coated spacers as well as uncoated 45° rotated spacers.The studied modified spacers were not effective for biofouling prevention and control. The impact of biofouling on FCP increase was reduced significantly by a lower linear flow velocity, while spacer orientation and spacer thickness in membrane modules had a smaller but still significant effect. © 2012 Elsevier B.V.

  7. A non-electrostatic spacer for aerosol delivery

    DEFF Research Database (Denmark)

    Bisgaard, H; Anhøj, J; Klug, B

    1995-01-01

    to 6 years, suspected to have asthma the non-electrostatic spacer delivered a mean total dose of budesonide aerosol of 39% of the nominal dose, which was significantly higher than the Babyhaler (28%), the Nebuhaler (21%), and the AeroChamber (19%). These differences were most pronounced in children......A pear shaped non-electrostatic spacer, composed of steel with a volume of 250 ml and equipped with a facemask containing integrated inlet and outlet valves for inspiration and expiration, was compared with three plastic spacers. The plastic spacers were primed with repeated puffs from a budesonide...... was 27 seconds and independent of the use of p-MDI. In vitro the maximum dose of budesonide from a p-MDI, expressed as a percentage of the nominal dose, was 56% from the non-electrostatic spacer, 61% from the Nebuhaler, 45% from the Babyhaler, and 30% from the AeroChamber. In 124 children, age 6 months...

  8. A non-electrostatic spacer for aerosol delivery

    DEFF Research Database (Denmark)

    Bisgaard, H; Anhøj, J; Klug, B

    1995-01-01

    A pear shaped non-electrostatic spacer, composed of steel with a volume of 250 ml and equipped with a facemask containing integrated inlet and outlet valves for inspiration and expiration, was compared with three plastic spacers. The plastic spacers were primed with repeated puffs from a budesonide...... pressurised metered dose inhaler (p-MDI) to minimise the electrostatic charge on the plastic. The procedure prolonged the half life (t1/2) of the aerosol in the Nebuhaler from nine to 32 seconds. A normal cleaning procedure reduced the aerosol t1/2 back to baseline. The t1/2 of the aerosol in the metal spacer...... was 27 seconds and independent of the use of p-MDI. In vitro the maximum dose of budesonide from a p-MDI, expressed as a percentage of the nominal dose, was 56% from the non-electrostatic spacer, 61% from the Nebuhaler, 45% from the Babyhaler, and 30% from the AeroChamber. In 124 children, age 6 months...

  9. Effects of near-ultraviolet light on mutations, intragenic and intergenic recombinations in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Machida, Isamu; Saeki, Tetsuya; Nakai, Sayaka

    1986-01-01

    The effects of far and near ultraviolet light on mutations, intragenic and intergenic recombinations were compared in diploid strains of Saccharomyces cerevisiae. At equivalent survival levels there was not much difference in the induction of nonsense and missense mutations between far- and near-UV radiations. However, frameshift mutations were induced more frequently by near-UV than by far-UV radiation. Near-UV radiation induced intragenic recombination as efficiently as far-UV radiation. A strikingly higher frequency was observed for the intergenic recombination induced by near-UV radiation than by far-UV radiation when compared at equivalent survival levels. Photoreactivation reduced the frequency only slightly in far-UV induced intergenic recombination and not at all in near-UV induction. These results indicate that near-UV damage involves strand breakage in addition to pyrimidine dimers and other lesions induced, whereas far-UV damage consists largely of photoreactivable lesions, pyrimidine dimers, and near-UV induced damage is more efficient for the induction of crossing-over. (Auth.)

  10. Comparative phylogenetic analysis of intergenic spacers and small ...

    African Journals Online (AJOL)

    The phylogenetic analysis of test isolates included assessment of variation in sequences and length of IGS and SSU-rRNA genes with reference to 16 different microsporidian sequences. The results proved that IGS sequences have more variation than SSU-rRNA gene sequences. Analysis of phylogenetic trees reveal that ...

  11. Molecular characterization of a novel bat-associated circovirus with a poly-T tract in the 3' intergenic region.

    Science.gov (United States)

    Zhu, Aiwei; Jiang, Tinglei; Hu, Tingsong; Mi, Shijiang; Zhao, Zihan; Zhang, Fuqiang; Feng, Jiang; Fan, Quanshui; He, Biao; Tu, Changchun

    2018-05-02

    The family Circoviridae comprises a large group of small circular single-stranded DNA viruses with several members causing severe pig and poultry diseases. In recent years the number of new viruses within the family has had an explosive increase showing a high level of genetic diversity and a broad host range. In this report we describe two more circoviruses identified from bats in Yunnan and Heilongjiang provinces in China. Full genome sequencing has revealed that these bat associated circoviruses (bat ACV) should be classified as new species within the genus Circovirus based on the demarcation criteria of the International Committee on the Taxonomy of Viruses (ICTV). The most striking result is the novel finding of a 21-28 nt polythymidine (poly-T) tract in the 3' terminal intergenic region of bat ACV isolates from Heilongjiang province. To understand its role in viral replication, a wild type bat ACV and a mutated version with the entire poly-T deleted were rescued through construction of infectious clones. Replication comparison in vitro showed that the poly-T is not essential for viral replication. Identification of additional bat ACV isolates and study of their biological characteristics will be the main task in future to understand the potential roles of bats in transmission of circoviruses to terrestrial mammals and humans. Copyright © 2018 Elsevier B.V. All rights reserved.

  12. A two-locus DNA sequence database for typing plant and human pathogens within the Fusarium oxysporum species complex

    DEFF Research Database (Denmark)

    O'Donnell, Kerry; Gueidan, C; Sink, S

    2009-01-01

    We constructed a two-locus database, comprising partial translation elongation factor (EF-1alpha) gene sequences and nearly full-length sequences of the nuclear ribosomal intergenic spacer region (IGS rDNA) for 850 isolates spanning the phylogenetic breadth of the Fusarium oxysporum species compl...... of the IGS rDNA sequences may be non-orthologous. We also evaluated enniatin, fumonisin and moniliformin mycotoxin production in vitro within a phylogenetic framework....

  13. High corrosion-resistant fuel spacers

    International Nuclear Information System (INIS)

    Yoshida, Toshimi; Takase, Iwao; Ikeda, Shinzo; Masaoka, Isao; Nakajima, Junjiro.

    1986-01-01

    Purpose: To enable manufacturing BWR fuel spacers by prior-art production process, using a zirconium-base alloy having very excellent corrosion resistance. Method: A highly improved nodular-resistant, corrosion-resistant zirconium alloy is devised by adding a slight amount of niobium, titanium and vanadium to zircaloy, of which fuel spacers are produced. That is, there can be obtained an alloy having much more excellent nodular resistance than conventional zircaloy, and free from a large change in plasticity, workability, and weldability, by adding to zirconium about 1.5 % of tin, about 0.15 % of iron, about 0.05 % of chromium, about 0.05 % of nickel, and 0.05 to 0.5 % of at least one or two kinds of niobium, titanium and vanadium. Using this zirconium-base alloy can manufacture fuel spacers by the same manufacturing process, thus improving economy and reliability. (Kamimura, M.)

  14. An Intergenic Region Shared by At4g35985 and At4g35987 in Arabidopsis thaliana Is a Tissue Specific and Stress Inducible Bidirectional Promoter Analyzed in Transgenic Arabidopsis and Tobacco Plants

    Science.gov (United States)

    Banerjee, Joydeep; Sahoo, Dipak Kumar; Dey, Nrisingha; Houtz, Robert L.; Maiti, Indu Bhushan

    2013-01-01

    On chromosome 4 in the Arabidopsis genome, two neighboring genes (calmodulin methyl transferase At4g35987 and senescence associated gene At4g35985) are located in a head-to-head divergent orientation sharing a putative bidirectional promoter. This 1258 bp intergenic region contains a number of environmental stress responsive and tissue specific cis-regulatory elements. Transcript analysis of At4g35985 and At4g35987 genes by quantitative real time PCR showed tissue specific and stress inducible expression profiles. We tested the bidirectional promoter-function of the intergenic region shared by the divergent genes At4g35985 and At4g35987 using two reporter genes (GFP and GUS) in both orientations in transient tobacco protoplast and Agro-infiltration assays, as well as in stably transformed transgenic Arabidopsis and tobacco plants. In transient assays with GFP and GUS reporter genes the At4g35985 promoter (P85) showed stronger expression (about 3.5 fold) compared to the At4g35987 promoter (P87). The tissue specific as well as stress responsive functional nature of the bidirectional promoter was evaluated in independent transgenic Arabidopsis and tobacco lines. Expression of P85 activity was detected in the midrib of leaves, leaf trichomes, apical meristemic regions, throughout the root, lateral roots and flowers. The expression of P87 was observed in leaf-tip, hydathodes, apical meristem, root tips, emerging lateral root tips, root stele region and in floral tissues. The bidirectional promoter in both orientations shows differential up-regulation (2.5 to 3 fold) under salt stress. Use of such regulatory elements of bidirectional promoters showing spatial and stress inducible promoter-functions in heterologous system might be an important tool for plant biotechnology and gene stacking applications. PMID:24260266

  15. An intergenic region shared by At4g35985 and At4g35987 in Arabidopsis thaliana is a tissue specific and stress inducible bidirectional promoter analyzed in transgenic arabidopsis and tobacco plants.

    Directory of Open Access Journals (Sweden)

    Joydeep Banerjee

    Full Text Available On chromosome 4 in the Arabidopsis genome, two neighboring genes (calmodulin methyl transferase At4g35987 and senescence associated gene At4g35985 are located in a head-to-head divergent orientation sharing a putative bidirectional promoter. This 1258 bp intergenic region contains a number of environmental stress responsive and tissue specific cis-regulatory elements. Transcript analysis of At4g35985 and At4g35987 genes by quantitative real time PCR showed tissue specific and stress inducible expression profiles. We tested the bidirectional promoter-function of the intergenic region shared by the divergent genes At4g35985 and At4g35987 using two reporter genes (GFP and GUS in both orientations in transient tobacco protoplast and Agro-infiltration assays, as well as in stably transformed transgenic Arabidopsis and tobacco plants. In transient assays with GFP and GUS reporter genes the At4g35985 promoter (P85 showed stronger expression (about 3.5 fold compared to the At4g35987 promoter (P87. The tissue specific as well as stress responsive functional nature of the bidirectional promoter was evaluated in independent transgenic Arabidopsis and tobacco lines. Expression of P85 activity was detected in the midrib of leaves, leaf trichomes, apical meristemic regions, throughout the root, lateral roots and flowers. The expression of P87 was observed in leaf-tip, hydathodes, apical meristem, root tips, emerging lateral root tips, root stele region and in floral tissues. The bidirectional promoter in both orientations shows differential up-regulation (2.5 to 3 fold under salt stress. Use of such regulatory elements of bidirectional promoters showing spatial and stress inducible promoter-functions in heterologous system might be an important tool for plant biotechnology and gene stacking applications.

  16. Differential effect of UV irradiation on induction of intragenic and intergenic recombination during commitment to meiosis in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Machida, I.; Nakai, S.

    1980-01-01

    A comparison was made between the induction of intragenic and intergenic recombinations during meiosis in a wild-type diploid of Saccharomyces cerevisiae. Under non-irradiated normal conditions, production of both intragenic and intergenic recombinants greatly increased in the cells with commitment to meiosis. The susceptibility of cells to the induction ob both the spontaneous intra- and intergenic recombinations in meiotic cells was similar. However, under condition of UV irradiation, there were striking differences between intra- and intergenic recombinations. Susceptibility to induction of intragenic recombination by UV irradiation was not enhanced at meiosis compared with mitosis, and was not altered through commitment to meiotic processes. In contrast, however, susceptibility to the induction of intergenic recombination by UV irradiation was enhanced markedly during commitment to meiosis compared with mitosis. Genetic analysis suggested that the enhanced susceptibility to recombination during meiosis is specifically concerned with reciprocal-type recombination (crossing-over) but not non-reciprocal-type recombination (gene conversion). Hence it is concluded that the meiotic that the meiotic process appears to be intimately concerned with the mechanism(s) of induction of recombination, especially reciprocal-type recombination. (orig.)

  17. CFD analysis of pressure drop across grid spacers in rod bundles compared to correlations and heavy liquid metal experimental data

    Energy Technology Data Exchange (ETDEWEB)

    Batta, A., E-mail: batta@kit.edu; Class, A.G., E-mail: class@kit.edu

    2017-02-15

    Early studies of the flow in rod bundles with spacer grids suggest that the pressure drop can be decomposed in contributions due to flow area variations by spacer grids and frictional losses along the rods. For these shape and frictional losses simple correlations based on theoretical and experimental data have been proposed. In the OECD benchmark study LACANES it was observed that correlations could well describe the flow behavior of the heavy liquid metal loop including a rod bundle with the exception of the core region, where different experts chose different pressure-loss correlations for the losses due to spacer grids. Here, RANS–CFD simulations provided very good data compared to the experimental data. It was observed that the most commonly applied Rehme correlation underestimated the shape losses. The available correlations relate the pressure drop across a grid spacer to the relative plugging of the spacer i.e. solidity e{sub max}. More sophisticated correlations distinct between spacer grids with round or sharp leading edge shape. The purpose of this study is to (i) show that CFD is suitable to predict pressure drop across spacer grids and (ii) to access the generality of pressure drop correlations. By verification and validation of CFD results against experimental data obtained in KALLA we show (i). The generality (ii) is challenged by considering three cases which yield identical pressure drop in the correlations. First we test the effect of surface roughness, a parameter not present in the correlations. Here we compare a simulation assuming a typical surface roughness representing the experimental situation to a perfectly smooth spacer surface. Second we reverse the flow direction for the spacer grid employed in the experiments which is asymmetric. The flow direction reversal is chosen for convenience, since an asymmetric spacer grid with given blockage ratio, may result in different flow situations depending on flow direction. Obviously blockage

  18. Genic and Intergenic SSR Database Generation, SNPs Determination and Pathway Annotations, in Date Palm (Phoenix dactylifera L.).

    Science.gov (United States)

    Mokhtar, Morad M; Adawy, Sami S; El-Assal, Salah El-Din S; Hussein, Ebtissam H A

    2016-01-01

    The present investigation was carried out aiming to use the bioinformatics tools in order to identify and characterize, simple sequence repeats within the third Version of the date palm genome and develop a new SSR primers database. In addition single nucleotide polymorphisms (SNPs) that are located within the SSR flanking regions were recognized. Moreover, the pathways for the sequences assigned by SSR primers, the biological functions and gene interaction were determined. A total of 172,075 SSR motifs was identified on date palm genome sequence with a frequency of 450.97 SSRs per Mb. Out of these, 130,014 SSRs (75.6%) were located within the intergenic regions with a frequency of 499 SSRs per Mb. While, only 42,061 SSRs (24.4%) were located within the genic regions with a frequency of 347.5 SSRs per Mb. A total of 111,403 of SSR primer pairs were designed, that represents 291.9 SSR primers per Mb. Out of the 111,403, only 31,380 SSR primers were in the genic regions, while 80,023 primers were in the intergenic regions. A number of 250,507 SNPs were recognized in 84,172 SSR flanking regions, which represents 75.55% of the total SSR flanking regions. Out of 12,274 genes only 463 genes comprising 896 SSR primers were mapped onto 111 pathways using KEGG data base. The most abundant enzymes were identified in the pathway related to the biosynthesis of antibiotics. We tested 1031 SSR primers using both publicly available date palm genome sequences as templates in the in silico PCR reactions. Concerning in vitro validation, 31 SSR primers among those used in the in silico PCR were synthesized and tested for their ability to detect polymorphism among six Egyptian date palm cultivars. All tested primers have successfully amplified products, but only 18 primers detected polymorphic amplicons among the studied date palm cultivars.

  19. Molecular Phylogenetic Screening of Withania somnifera Relative From Indonesia Based on Internal Transcribed Spacer Region

    Directory of Open Access Journals (Sweden)

    Topik Hidayat

    2016-04-01

    Full Text Available Withania somnifera (family Solanaceae, known commonly as Ashwaganda, is one of the important medicinal plants, and recent studies reported that Withanone, one of the chemical components in this plant, has ability to kill cancer cell. Because of endemic state of this plant to South Asia, exploring plant species under the same family which grow well in Indonesia has been of interest. The purpose of this study was to screen the Indonesian plant which has strong phylogenetic relationship with Ashwaganda. Thus, phylogenetic analysis using DNA sequences of internal transcribed spacer (ITS region was conducted. Thus, 19 species of Solanaceae and two species of Convolvulaceae as outgroup were examined. Five ITS regions of Ashwaganda retrieved from GenBank were included in the phylogenetic analysis. Parsimony analysis showed that Indonesia Solanaceae comprises seven groups which is consistent with the global Solanaceae relationship as previously reported. Furthermore, our study revealed that two species, Physalis angulata and Physalis peruviana, are relative to W. somnifera. Morphologically, they share characters of flower and fruit. This result indicated that these two species are potential to have similar chemical properties as Ashwaganda, thus we can have new variants of Withanone originated from Indonesia with similar effect.

  20. Cre recombinase activity is inhibited in vivo but not ex vivo by a mutation in the asymmetric spacer region of the distal loxP site.

    Science.gov (United States)

    Arguello, Tania; Moraes, Carlos T

    2015-11-01

    The cre/loxP recombination system is a valuable tool used to generate tissue specific genomic rearrangements in mouse models. The deletion of a region of interest flanked by two loxP sites is accomplished by the recombinase (cre) enzyme, which binds to the inverted repeat segments of two loxP sites and recognition of a conserved TA sequence in the asymmetric central spacer region "ATAACTTCGTATA -NNNTANNN-TATACGAAGTTAT. In vivo, we found that a single T to C mutation at position 4 of the central spacer region in the distal (3') loxP site, completely inhibited the recombination reaction in two conditional mouse models. These mice were generated using a mitochondrial methionyl-tRNA formyltransferase (Mtfmt) gene targeted construct and cre transgene under the control of tissue-specific promoters: calcium/calmodulin-dependent kinase II alpha (Camk2a-cre) and myosin light polypeptide 1 (Myl1-cre). Surprisingly, transient transfection of a plasmid expressing cre in dermal fibroblasts derived from the same mutant floxed Mtfmt((loxP/loxP)) mice line, successfully deleted the region of interest. This study demonstrates the sequence specificity required in vivo, the possibility of bypassing this limitation by expressing high levels of cre recombinase ex vivo and raises concerns related to the quality control of large scale production of gene targeted constructs and mice. genesis 53:695-700, 2015. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  1. Nanoparticle-Based Brachytherapy Spacers for Delivery of Localized Combined Chemoradiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Rajiv, E-mail: r.kumar@neu.edu [Nanomedicine Science and Technology Center, Northeastern University, Boston, Massachusetts (United States); Department of Radiation Oncology, Brigham and Women' s Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts (United States); Belz, Jodi [Nanomedicine Science and Technology Center, Northeastern University, Boston, Massachusetts (United States); Markovic, Stacey [Department of Electrical and Computer Engineering, Northeastern University, Boston, Massachusetts (United States); Jadhav, Tej; Fowle, William [Nanomedicine Science and Technology Center, Northeastern University, Boston, Massachusetts (United States); Niedre, Mark [Department of Electrical and Computer Engineering, Northeastern University, Boston, Massachusetts (United States); Cormack, Robert; Makrigiorgos, Mike G. [Department of Radiation Oncology, Brigham and Women' s Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts (United States); Sridhar, Srinivas [Nanomedicine Science and Technology Center, Northeastern University, Boston, Massachusetts (United States); Department of Radiation Oncology, Brigham and Women' s Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts (United States)

    2015-02-01

    Purpose: In radiation therapy (RT), brachytherapy-inert source spacers are commonly used in clinical practice to achieve high spatial accuracy. These implanted devices are critical technical components of precise radiation delivery but provide no direct therapeutic benefits. Methods and Materials: Here we have fabricated implantable nanoplatforms or chemoradiation therapy (INCeRT) spacers loaded with silica nanoparticles (SNPs) conjugated containing a drug, to act as a slow-release drug depot for simultaneous localized chemoradiation therapy. The spacers are made of poly(lactic-co-glycolic) acid (PLGA) as matrix and are physically identical in size to the commercially available brachytherapy spacers (5 mm × 0.8 mm). The silica nanoparticles, 250 nm in diameter, were conjugated with near infrared fluorophore Cy7.5 as a model drug, and the INCeRT spacers were characterized in terms of size, morphology, and composition using different instrumentation techniques. The spacers were further doped with an anticancer drug, docetaxel. We evaluated the in vivo stability, biocompatibility, and biodegradation of these spacers in live mouse tissues. Results: The electron microscopy studies showed that nanoparticles were distributed throughout the spacers. These INCeRT spacers remained stable and can be tracked by the use of optical fluorescence. In vivo optical imaging studies showed a slow diffusion of nanoparticles from the spacer to the adjacent tissue in contrast to the control Cy7.5-PLGA spacer, which showed rapid disintegration in a few days with a burst release of Cy7.5. The docetaxel spacers showed suppression of tumor growth in contrast to control mice over 16 days. Conclusions: The imaging with the Cy7.5 spacer and therapeutic efficacy with docetaxel spacers supports the hypothesis that INCeRT spacers can be used for delivering the drugs in a slow, sustained manner in conjunction with brachytherapy, in contrast to the rapid clearance of the drugs when

  2. Nanoparticle-Based Brachytherapy Spacers for Delivery of Localized Combined Chemoradiation Therapy

    International Nuclear Information System (INIS)

    Kumar, Rajiv; Belz, Jodi; Markovic, Stacey; Jadhav, Tej; Fowle, William; Niedre, Mark; Cormack, Robert; Makrigiorgos, Mike G.; Sridhar, Srinivas

    2015-01-01

    Purpose: In radiation therapy (RT), brachytherapy-inert source spacers are commonly used in clinical practice to achieve high spatial accuracy. These implanted devices are critical technical components of precise radiation delivery but provide no direct therapeutic benefits. Methods and Materials: Here we have fabricated implantable nanoplatforms or chemoradiation therapy (INCeRT) spacers loaded with silica nanoparticles (SNPs) conjugated containing a drug, to act as a slow-release drug depot for simultaneous localized chemoradiation therapy. The spacers are made of poly(lactic-co-glycolic) acid (PLGA) as matrix and are physically identical in size to the commercially available brachytherapy spacers (5 mm × 0.8 mm). The silica nanoparticles, 250 nm in diameter, were conjugated with near infrared fluorophore Cy7.5 as a model drug, and the INCeRT spacers were characterized in terms of size, morphology, and composition using different instrumentation techniques. The spacers were further doped with an anticancer drug, docetaxel. We evaluated the in vivo stability, biocompatibility, and biodegradation of these spacers in live mouse tissues. Results: The electron microscopy studies showed that nanoparticles were distributed throughout the spacers. These INCeRT spacers remained stable and can be tracked by the use of optical fluorescence. In vivo optical imaging studies showed a slow diffusion of nanoparticles from the spacer to the adjacent tissue in contrast to the control Cy7.5-PLGA spacer, which showed rapid disintegration in a few days with a burst release of Cy7.5. The docetaxel spacers showed suppression of tumor growth in contrast to control mice over 16 days. Conclusions: The imaging with the Cy7.5 spacer and therapeutic efficacy with docetaxel spacers supports the hypothesis that INCeRT spacers can be used for delivering the drugs in a slow, sustained manner in conjunction with brachytherapy, in contrast to the rapid clearance of the drugs when

  3. Development of structural technology for a high performance spacer grid

    International Nuclear Information System (INIS)

    Song, Kee Nam; Kim, H. K.; Kang, H. S.

    2003-03-01

    A spacer grid in a LWR fuel assembly is a key structural component to support fuel rods and to enhance the heat transfer from the fuel rod to the coolant. In this research, the main research items are the development of inherent and high performance spacer grid shapes, the establishment of mechanical/structural analysis and test technology, and the set-up of basic test facilities for the spacer grid. The main research areas and results are as follows. 1. 14 different spacer grid candidates have been invented and applied for domestic and US patents. Among the candidates six are chosen from the patent. 2. Two kinds of spacer grids are finally selected for the advanced LWR fuel after detailed performance tests on the candidates and commercial spacer grids from a mechanical/structural point of view. According to the test results the features of the selected spacer grids are better than those of the commercial spacer grids. 3. Four kinds of basic test facilities are set up and the relevant test technologies are established. 4. Mechanical/structural analysis models and technology for spacer grid performance are developed and the analysis results are compared with the test results to enhance the reliability of the models

  4. Genetic diversity of Streptococcus equi subsp. zooepidemicus and doxycycline resistance in kennelled dogs.

    Science.gov (United States)

    Chalker, Victoria J; Waller, Andrew; Webb, Katy; Spearing, Emma; Crosse, Patricia; Brownlie, Joe; Erles, Kerstin

    2012-06-01

    The genetic diversity and antibiotic resistance profiles of 38 Streptococcus equi subsp. zooepidemicus isolates were determined from a kennelled canine population during two outbreaks of hemorrhagic pneumonia (1999 to 2002 and 2007 to 2010). Analysis of the szp gene hypervariable region and the 16S-23S rRNA intergenic spacer region and multilocus sequence typing (MLST) indicated a predominant tetO-positive, doxycycline-resistant ST-10 strain during 1999 to 2002 and a predominant tetM-positive doxycycline-resistant ST-62 strain during 2007 to 2010.

  5. Dispersals of Hyoscyameae and Mandragoreae (Solanaceae) from the New World to Eurasia in the early Miocene and their biogeographic diversification within Eurasia.

    Science.gov (United States)

    Tu, Tieyao; Volis, Sergei; Dillon, Michael O; Sun, Hang; Wen, Jun

    2010-12-01

    The cosmopolitan Solanaceae contains 21 tribes and has the greatest diversity in South America. Hyoscyameae and Mandragoreae are the only tribes of this family distributed exclusively in Eurasia with two centers of diversity: the Mediterranean-Turanian (MT) region and the Tibetan Plateau (TP). In this study, we examined the origins and biogeographical diversifications of the two tribes based on the phylogenetic framework and chronogram inferred from a combined data set of six plastid DNA regions (the atpB gene, the ndhF gene, the rps16-trnK intergenic spacer, the rbcL gene, the trnC-psbM region and the psbA-trnH intergenic spacer) with two fossil calibration points. Our data suggest that Hyoscyameae and Mandragoreae each forms a monophyletic group independently derived from different New World lineages in the early Miocene. Phylogenetic relationships within both tribes are generally well resolved. All genera of Hyoscyameae are found to be monophyletic and they diversified in middle to late Miocene. At nearly the same time, Mandragoreae split into two clades, corresponding to the MT region and the TP region, respectively. Both the phylogenetic relationships and the estimated ages of Hyoscyameae and Mandragoreae support two independent dispersal events of their ancestors from the New World into Eurasia. After their arrivals in Eurasia, the two tribes diversified primarily in the MT region and in the TP region via multiple biogeographic processes including vicariance, dispersal, recolonization or being preserved as relicts, from the mid Miocene to the late Quaternary. Published by Elsevier Inc.

  6. Intergenic sequence between Arabidopsis caseinolytic protease B-cytoplasmic/heat shock protein100 and choline kinase genes functions as a heat-inducible bidirectional promoter.

    Science.gov (United States)

    Mishra, Ratnesh Chandra; Grover, Anil

    2014-11-01

    In Arabidopsis (Arabidopsis thaliana), the At1g74310 locus encodes for caseinolytic protease B-cytoplasmic (ClpB-C)/heat shock protein100 protein (AtClpB-C), which is critical for the acquisition of thermotolerance, and At1g74320 encodes for choline kinase (AtCK2) that catalyzes the first reaction in the Kennedy pathway for phosphatidylcholine biosynthesis. Previous work has established that the knockout mutants of these genes display heat-sensitive phenotypes. While analyzing the AtClpB-C promoter and upstream genomic regions in this study, we noted that AtClpB-C and AtCK2 genes are head-to-head oriented on chromosome 1 of the Arabidopsis genome. Expression analysis showed that transcripts of these genes are rapidly induced in response to heat stress treatment. In stably transformed Arabidopsis plants harboring this intergenic sequence between head-to-head oriented green fluorescent protein and β-glucuronidase reporter genes, both transcripts and proteins of the two reporters were up-regulated upon heat stress. Four heat shock elements were noted in the intergenic region by in silico analysis. In the homozygous transfer DNA insertion mutant Salk_014505, 4,393-bp transfer DNA is inserted at position -517 upstream of ATG of the AtClpB-C gene. As a result, AtCk2 loses proximity to three of the four heat shock elements in the mutant line. Heat-inducible expression of the AtCK2 transcript was completely lost, whereas the expression of AtClpB-C was not affected in the mutant plants. Our results suggest that the 1,329-bp intergenic fragment functions as a heat-inducible bidirectional promoter and the region governing the heat inducibility is possibly shared between the two genes. We propose a model in which AtClpB-C shares its regulatory region with heat-induced choline kinase, which has a possible role in heat signaling. © 2014 American Society of Plant Biologists. All Rights Reserved.

  7. Hydraulic Design Criteria for Spacer Grids of Nuclear Fuel Element

    International Nuclear Information System (INIS)

    Juanico, Luis; Brasnarof, Daniel

    2000-01-01

    In this paper a hydraulic model for calculating the pressure drop on the CARA spacer grids is extended.This model is validated and feedback from experimental hydraulic test performed in a low pressure loop.The importance of the spacer grid geometric parameter (that is, its thickness and length, the number and kind of their fix spacer), developing hydraulic design criteria for spacer grid on fuel element

  8. Preclinical Evaluation of Bioabsorbable Polyglycolic Acid Spacer for Particle Therapy

    International Nuclear Information System (INIS)

    Akasaka, Hiroaki; Sasaki, Ryohei; Miyawaki, Daisuke; Mukumoto, Naritoshi; Sulaiman, Nor Shazrina Binti; Nagata, Masaaki; Yamada, Shigeru; Murakami, Masao; Demizu, Yusuke; Fukumoto, Takumi

    2014-01-01

    Purpose: To evaluate the efficacy and safety of a polyglycolic acid (PGA) spacer through physical and animal experiments. Methods and Materials: The spacer was produced with surgical suture material made of PGA, forming a 3-dimensional nonwoven fabric. For evaluation or physical experiments, 150-MeV proton or 320-MeV carbon-ion beams were used to generate 60-mm width of spread-out Bragg peak. For animal experiments, the abdomens of C57BL/6 mice, with or without the inserted PGA spacers, were irradiated with 20 Gy of carbon-ion beam (290 MeV) using the spread-out Bragg peak. Body weight changes over time were scored, and radiation damage to the intestine was investigated using hematoxylin and eosin stain. Blood samples were also evaluated 24 days after the irradiation. Long-term thickness retention and safety were evaluated using crab-eating macaques. Results: No chemical or structural changes after 100 Gy of proton or carbon-ion irradiation were observed in the PGA spacer. Water equivalency of the PGA spacer was equal to the water thickness under wet condition. During 24 days' observation after 20 Gy of carbon-ion irradiation, the body weights of mice with the PGA spacer were relatively unchanged, whereas significant weight loss was observed in those mice without the PGA spacer (P<.05). In mice with the PGA spacer, villus and crypt structure were preserved after irradiation. No inflammatory reactions or liver or renal dysfunctions due to placement of the PGA spacer were observed. In the abdomen of crab-eating macaques, thickness of the PGA spacer was maintained 8 weeks after placement. Conclusions: The absorbable PGA spacer had water-equivalent, bio-compatible, and thickness-retaining properties. Although further evaluation is warranted in a clinical setting, the PGA spacer may be effective to stop proton or carbon-ion beams and to separate normal tissues from the radiation field

  9. The complete mitochondrial genome of the rice moth, Corcyra cephalonica.

    Science.gov (United States)

    Wu, Yu-Peng; Li, Jie; Zhao, Jin-Liang; Su, Tian-Juan; Luo, A-Rong; Fan, Ren-Jun; Chen, Ming-Chang; Wu, Chun-Sheng; Zhu, Chao-Dong

    2012-01-01

    The complete mitochondrial genome (mitogenome) of the rice moth, Corcyra cephalonica Stainton (Lepidoptera: Pyralidae) was determined as a circular molecular of 15,273 bp in size. The mitogenome composition (37 genes) and gene order are the same as the other lepidopterans. Nucleotide composition of the C. cephalonica mitogenome is highly A+T biased (80.43%) like other insects. Twelve protein-coding genes start with a typical ATN codon, with the exception of coxl gene, which uses CGA as the initial codon. Nine protein-coding genes have the common stop codon TAA, and the nad2, cox1, cox2, and nad4 have single T as the incomplete stop codon. 22 tRNA genes demonstrated cloverleaf secondary structure. The mitogenome has several large intergenic spacer regions, the spacer1 between trnQ gene and nad2 gene, which is common in Lepidoptera. The spacer 3 between trnE and trnF includes microsatellite-like repeat regions (AT)18 and (TTAT)(3). The spacer 4 (16 bp) between trnS2 gene and nad1 gene has a motif ATACTAT; another species, Sesamia inferens encodes ATCATAT at the same position, while other lepidopteran insects encode a similar ATACTAA motif. The spacer 6 is A+T rich region, include motif ATAGA and a 20-bp poly(T) stretch and two microsatellite (AT)(9), (AT)(8) elements.

  10. Zircaloy spacer grid for boiling light water reactors

    International Nuclear Information System (INIS)

    Borgiani, F.; Cali', G.P.; Cerretti, P.; Pazzo, P.

    1975-01-01

    The need to increase the neutronic efficiency of the new cores of BWR's, lead to study types of spacer-grids made of low neutronic absorption materials as zircaloy-4. The particular mechanical behaviour of this material suggested to design a spacer-grids such as to utilize only blanking, slotting and bending operations as plastic forming and to avoid therefore drawing effects. The optimization of the bending procedures lead to a final spacer-grids configuration equally stiff in all directions and planes. Only for the ''elastic constraints'' nichel alloy sheets were used to made easy the whole spacer design. The ''rigid constraints'', supporting the rods, have been obtained directly from the spacer structure. Calculations were performed to verify the mechanical strength of the main grid components. In this framework a computer code was developed to find the best elastic characteristic of the ''elastic constraints'' taking into account the machining tolerances. Some original methods to test the integral behaviour of the grid assembled as well as the procedures to be adopted for its best maintenance, are described

  11. Mechanical/structural performance test method of a spacer grid

    International Nuclear Information System (INIS)

    Yoon, Kyung Ho

    2000-06-01

    The spacer grid is one of the main structural components in the fuel assembly, which supports the fuel rods, guides cooling water, and protects the system from an external impact load, such as earthquakes. In order to develop the spacer grid with the high mechanical performance, the mechanical and structural properties of the spacer grids must be extensively examined while designing it. In this report, the mechanical/structural test methods, i.e. the characteristic test of a spacer grid spring or dimple, static buckling test of a partial or full size spacer grid and dynamic impact test of them are described. The characteristic test of a spacer grid spring or dimple is accomplished with universal tensile test machine, a specimen is fixed with test fixture and then applied compressive load. The characteristic test data is saved at loading and unloading event. The static buckling test of a partial or full size spacer grid is executed with the same universal tensile testing machine, a specimen is fixed between cross-heads and then applied the compressive load. The buckling strength is decided the maximum strength at load vs. displacement curve. The dynamic impact test of a partial or full size spacer grid is performed with pendulum type impact machine and free fall shock test machine, a specimen is fixed with test fixture and then applied the impact load by impact hammer. Specially, the pendulum type impact test machine is also possible under the operating temperature because a furnace is separately attached with test machine

  12. Bioinformatics analyses of Shigella CRISPR structure and spacer classification.

    Science.gov (United States)

    Wang, Pengfei; Zhang, Bing; Duan, Guangcai; Wang, Yingfang; Hong, Lijuan; Wang, Linlin; Guo, Xiangjiao; Xi, Yuanlin; Yang, Haiyan

    2016-03-01

    Clustered regularly interspaced short palindromic repeats (CRISPR) are inheritable genetic elements of a variety of archaea and bacteria and indicative of the bacterial ecological adaptation, conferring acquired immunity against invading foreign nucleic acids. Shigella is an important pathogen for anthroponosis. This study aimed to analyze the features of Shigella CRISPR structure and classify the spacers through bioinformatics approach. Among 107 Shigella, 434 CRISPR structure loci were identified with two to seven loci in different strains. CRISPR-Q1, CRISPR-Q4 and CRISPR-Q5 were widely distributed in Shigella strains. Comparison of the first and last repeats of CRISPR1, CRISPR2 and CRISPR3 revealed several base variants and different stem-loop structures. A total of 259 cas genes were found among these 107 Shigella strains. The cas gene deletions were discovered in 88 strains. However, there is one strain that does not contain cas gene. Intact clusters of cas genes were found in 19 strains. From comprehensive analysis of sequence signature and BLAST and CRISPRTarget score, the 708 spacers were classified into three subtypes: Type I, Type II and Type III. Of them, Type I spacer referred to those linked with one gene segment, Type II spacer linked with two or more different gene segments, and Type III spacer undefined. This study examined the diversity of CRISPR/cas system in Shigella strains, demonstrated the main features of CRISPR structure and spacer classification, which provided critical information for elucidation of the mechanisms of spacer formation and exploration of the role the spacers play in the function of the CRISPR/cas system.

  13. Stress Analysis of Single Spacer Grid Support considering Fuel Rod

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Y. G.; Jung, D. H.; Kim, J. H. [Chungnam National University, Daejeon (Korea, Republic of); Park, J. K.; Jeon, K. L. [Korea Nuclear Fuel, Daejeon (Korea, Republic of)

    2010-10-15

    Pressurized water reactor (PWR) nuclear fuel assembly is mainly composed of a top-end piece, a bottom-end piece, lots of fuel rods, and several spacer grids. Among them, the main function of spacer grid is protecting fuel rods from Fluid Induced Vibration (FIV). The cross section of spacer grid assembled by laser welding in upper and lower point. When the fuel rod inserted in spacer gird, spring and dimple and around of welded area got a stresses. The main hypothesis of this analysis is the boundary area of HAZ and base metal can get a lot of damage than other area by FIV. So, design factors of spacer grid mainly considered to preventing the fatigue failure in HAZ and spring and dimple of spacer grid. From previous researching, the environment in reactor verified. Pressure and temperature of light water observed 15MPa and 320 .deg. C, and vibration of the fuel rod observed within 0 {approx} 50Hz. In this study, mechanical properties of zirconium alloy that extracted from the test and the spacer grid model which used in the PWR were applied in stress analyzing. General-purpose finite element analysis program was used ANSYS Workbench 12.0.1 version. 3-D CAD program CATIA was used to create spacer grid model

  14. Biomechanical Analysis of an Expandable Lumbar Interbody Spacer.

    Science.gov (United States)

    Soriano-Baron, Hector; Newcomb, Anna G U S; Malhotra, Devika; Palma, Atilio E; Martinez-Del-Campo, Eduardo; Crawford, Neil R; Theodore, Nicholas; Kelly, Brian P; Kaibara, Taro

    2018-06-01

    Recently developed expandable interbody spacers are widely accepted in spinal surgery; however, the resulting biomechanical effects of their use have not yet been fully studied. We analyzed the biomechanical effects of an expandable polyetheretherketone interbody spacer inserted through a bilateral posterior approach with and without different modalities of posterior augmentation. Biomechanical nondestructive flexibility testing was performed in 7 human cadaveric lumbar (L2-L5) specimens followed by axial compressive loading. Each specimen was tested under 6 conditions: 1) intact, 2) bilateral L3-L4 cortical screw/rod (CSR) alone, 3) WaveD alone, 4) WaveD + CSR, 5) WaveD + bilateral L3-L4 pedicle screw/rod (PSR), and 6) WaveD + CSR/PSR, where CSR/PSR was a hybrid construct comprising bilateral cortical-level L3 and pedicle-level L4 screws interconnected by rods. The range of motion (ROM) with the interbody spacer alone decreased significantly compared with the intact condition during flexion-extension (P = 0.02) but not during lateral bending or axial rotation (P ≥ 0.19). The addition of CSR or PSR to the interbody spacer alone condition significantly decreased the ROM compared with the interbody spacer alone (P ≤ 0.002); and WaveD + CSR, WaveD + PSR, and WaveD + CSR/PSR (hybrid) (P ≥ 0.29) did not differ. The axial compressive stiffness (resistance to change in foraminal height during compressive loading) with the interbody spacer alone did not differ from the intact condition (P = 0.96), whereas WaveD + posterior instrumentation significantly increased compressive stiffness compared with the intact condition and the interbody spacer alone (P ≤ 0.001). The WaveD alone significantly reduced ROM during flexion-extension while maintaining the axial compressive stiffness. CSR, PSR, and CSR/PSR hybrid constructs were all effective in augmenting the expandable interbody spacer system and improving its stability. Copyright © 2018 Elsevier Inc. All

  15. CFD application to advanced design for high efficiency spacer grid

    International Nuclear Information System (INIS)

    Ikeda, Kazuo

    2014-01-01

    Highlights: • A new LDV was developed to investigate the local velocity in a rod bundle and inside a spacer grid. • The design information that utilizes for high efficiency spacer grid has been obtained. • CFD methodology that predicts flow field in a PWR fuel has been developed. • The high efficiency spacer grid was designed using the CFD methodology. - Abstract: Pressurized water reactor (PWR) fuels have been developed to meet the needs of the market. A spacer grid is a key component to improve thermal hydraulic performance of a PWR fuel assembly. Mixing structures (vanes) of a spacer grid promote coolant mixing and enhance heat removal from fuel rods. A larger mixing vane would improve mixing effect, which would increase the departure from nucleate boiling (DNB) benefit for fuel. However, the increased pressure loss at large mixing vanes would reduce the coolant flow at the mixed fuel core, which would reduce the DNB margin. The solution is to develop a spacer grid whose pressure loss is equal to or less than the current spacer grid and that has higher critical heat flux (CHF) performance. For this reason, a requirement of design tool for predicting the pressure loss and CHF performance of spacer grids has been increased. The author and co-workers have been worked for development of high efficiency spacer grid using Computational Fluid Dynamics (CFD) for nearly 20 years. A new laser Doppler velocimetry (LDV), which is miniaturized with fiber optics embedded in a fuel cladding, was developed to investigate the local velocity profile in a rod bundle and inside a spacer grid. The rod-embedded fiber LDV (rod LDV) can be inserted in an arbitrary grid cell instead of a fuel rod, and has the advantage of not disturbing the flow field since it is the same shape as a fuel rod. The probe volume of the rod LDV is small enough to measure spatial velocity profile in a rod gap and inside a spacer grid. According to benchmark experiments such as flow velocity

  16. CFD application to advanced design for high efficiency spacer grid

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, Kazuo, E-mail: kazuo3_ikeda@ndc.mhi.co.jp

    2014-11-15

    Highlights: • A new LDV was developed to investigate the local velocity in a rod bundle and inside a spacer grid. • The design information that utilizes for high efficiency spacer grid has been obtained. • CFD methodology that predicts flow field in a PWR fuel has been developed. • The high efficiency spacer grid was designed using the CFD methodology. - Abstract: Pressurized water reactor (PWR) fuels have been developed to meet the needs of the market. A spacer grid is a key component to improve thermal hydraulic performance of a PWR fuel assembly. Mixing structures (vanes) of a spacer grid promote coolant mixing and enhance heat removal from fuel rods. A larger mixing vane would improve mixing effect, which would increase the departure from nucleate boiling (DNB) benefit for fuel. However, the increased pressure loss at large mixing vanes would reduce the coolant flow at the mixed fuel core, which would reduce the DNB margin. The solution is to develop a spacer grid whose pressure loss is equal to or less than the current spacer grid and that has higher critical heat flux (CHF) performance. For this reason, a requirement of design tool for predicting the pressure loss and CHF performance of spacer grids has been increased. The author and co-workers have been worked for development of high efficiency spacer grid using Computational Fluid Dynamics (CFD) for nearly 20 years. A new laser Doppler velocimetry (LDV), which is miniaturized with fiber optics embedded in a fuel cladding, was developed to investigate the local velocity profile in a rod bundle and inside a spacer grid. The rod-embedded fiber LDV (rod LDV) can be inserted in an arbitrary grid cell instead of a fuel rod, and has the advantage of not disturbing the flow field since it is the same shape as a fuel rod. The probe volume of the rod LDV is small enough to measure spatial velocity profile in a rod gap and inside a spacer grid. According to benchmark experiments such as flow velocity

  17. Effects of spacer orientations on the cake formation during membrane fouling: Quantitative analysis based on 3D OCT imaging.

    Science.gov (United States)

    Liu, Xin; Li, Weiyi; Chong, Tzyy Haur; Fane, Anthony G

    2017-03-01

    Spacer design plays an important role in improving the performance of membrane processes for water/wastewater treatment. This work focused on a fundamental issue of spacer design, i.e., investigating the effects of spacer orientations on the fouling behavior during a membrane process. A series of fouling experiments with different spacer orientation were carried out to in situ characterize the formation of a cake layer in a spacer unit cell via 3D optical coherence tomography (OCT) imaging. The cake layers formed at different times were digitalized for quantitatively analyzing the variation in the cake morphology as a function of time. In particular, the local deposition rates were evaluated to determine the active regions where the instantaneous changes in deposit thickness were significant. The characterization results indicate that varying the spacer orientation could substantially change the evolution of membrane fouling by particulate foulants and thereby result in a cake layer with various morphologies; the competition between growth and erosion at different locations would instantaneously respond to the micro-hydrodynamic environment that might change with time. This work confirms that the OCT-based characterization method is a powerful tool for exploring novel spacer design. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Development and evaluation of specific PCR primers targeting the ribosomal DNA-internal transcribed spacer (ITS) region of peritrich ciliates in environmental samples

    Science.gov (United States)

    Su, Lei; Zhang, Qianqian; Gong, Jun

    2017-07-01

    Peritrich ciliates are highly diverse and can be important bacterial grazers in aquatic ecosystems. Morphological identifications of peritrich species and assemblages in the environment are time-consuming and expertise-demanding. In this study, two peritrich-specific PCR primers were newly designed to amplify a fragment including the internal transcribed spacer (ITS) region of ribosomal rDNA from environmental samples. The primers showed high specificity in silico, and in tests with peritrich isolates and environmental DNA. Application of these primers in clone library construction and sequencing yielded exclusively sequences of peritrichs for water and sediment samples. We also found the ITS1, ITS2, ITS, D1 region of 28S rDNA, and ITS+D1 region co-varied with, and generally more variable than, the V9 region of 18S rDNA in peritrichs. The newly designed specific primers thus provide additional tools to study the molecular diversity, community composition, and phylogeography of these ecologically important protists in different systems.

  19. Comparison of four polymerase chain reaction assays for the detection of Brucella spp. in clinical samples from dogs

    Directory of Open Access Journals (Sweden)

    Eduardo J. Boeri

    2018-02-01

    Full Text Available Aim: This study aimed to compare the sensitivity (S, specificity (Sp, and positive likelihood ratios (LR+ of four polymerase chain reaction (PCR assays for the detection of Brucella spp. in dog's clinical samples. Materials and Methods: A total of 595 samples of whole blood, urine, and genital fluids were evaluated between October 2014 and November 2016. To compare PCR assays, the gold standard was defined using a combination of different serological and microbiological test. Bacterial isolation from urine and blood cultures was carried out. Serological methods such as rapid slide agglutination test, indirect enzyme-linked immunosorbent assay, agar gel immunodiffusion test, and buffered plate antigen test were performed. Four genes were evaluated: (i The gene coding for the BCSP31 protein, (ii the ribosomal gene coding for the 16S-23S intergenic spacer region, (iii the gene coding for porins omp2a/omp2b, and (iv the gene coding for the insertion sequence IS711. Results: The results obtained were as follows: (1 For the primers that amplify the gene coding for the BCSP31 protein: S: 45.64% (confidence interval [CI] 39.81-51.46, Sp: 95.62% (CI 93.13-98.12, and LR+: 10.43 (CI 6.04-18; (2 for the primers that amplify the ribosomal gene of the 16S-23S rDNA intergenic spacer region: S: 69.80% (CI 64.42-75.18, Sp: 95.62 % (CI 93.13-98.12, and LR+: 11.52 (CI 7.31-18.13; (3 for the primers that amplify the omp2a and omp2b genes: S: 39.26% (CI 33.55-44.97, Sp: 97.31% (CI 95.30-99.32, and LR+ 14.58 (CI 7.25-29.29; and (4 for the primers that amplify the insertion sequence IS711: S: 22.82% (CI 17.89 - 27.75, Sp: 99.66% (CI 98.84-100, and LR+ 67.77 (CI 9.47-484.89. Conclusion: We concluded that the gene coding for the 16S-23S rDNA intergenic spacer region was the one that best detected Brucella spp. in canine clinical samples.

  20. Fuel assembly spacer

    International Nuclear Information System (INIS)

    Shirakawa, Ken-etsu.

    1988-01-01

    Purpose: To reduce the pressure loss of coolants by fuel assembly spacers. Constitution: Spacers for supporting a fuel assembly are attached by means of a plurality of wires to an outer frame. The outer frame is made of shape memory alloy such that the wires are caused to slacken at normal temperature and the slacking of the wires is eliminated in excess of the transition temperature. Since the wires slacken at the normal temperature, fuel rods can be inserted easily. After the insertion of the fuel rods, when the entire portion or the outer frame is heated by water or gas at a predetermined temperature, the outer frame resumes its previously memorized shape to tighten the wires and, accordingly, the fuel rods can be supported firmly. In this way, since the fuel rods are inserted in the slacken state of the wires and, after the assembling, the outer frame resumes its memorized shape, the assembling work can be conducted efficiently. (Kamimura, M.)

  1. Multiple independent origins of mitochondrial control region duplications in the order Psittaciformes

    Science.gov (United States)

    Schirtzinger, Erin E.; Tavares, Erika S.; Gonzales, Lauren A.; Eberhard, Jessica R.; Miyaki, Cristina Y.; Sanchez, Juan J.; Hernandez, Alexis; Müeller, Heinrich; Graves, Gary R.; Fleischer, Robert C.; Wright, Timothy F.

    2012-01-01

    Mitochondrial genomes are generally thought to be under selection for compactness, due to their small size, consistent gene content, and a lack of introns or intergenic spacers. As more animal mitochondrial genomes are fully sequenced, rearrangements and partial duplications are being identified with increasing frequency, particularly in birds (Class Aves). In this study, we investigate the evolutionary history of mitochondrial control region states within the avian order Psittaciformes (parrots and cockatoos). To this aim, we reconstructed a comprehensive multi-locus phylogeny of parrots, used PCR of three diagnostic fragments to classify the mitochondrial control region state as single or duplicated, and mapped these states onto the phylogeny. We further sequenced 44 selected species to validate these inferences of control region state. Ancestral state reconstruction using a range of weighting schemes identified six independent origins of mitochondrial control region duplications within Psittaciformes. Analysis of sequence data showed that varying levels of mitochondrial gene and tRNA homology and degradation were present within a given clade exhibiting duplications. Levels of divergence between control regions within an individual varied from 0–10.9% with the differences occurring mainly between 51 and 225 nucleotides 3′ of the goose hairpin in domain I. Further investigations into the fates of duplicated mitochondrial genes, the potential costs and benefits of having a second control region, and the complex relationship between evolutionary rates, selection, and time since duplication are needed to fully explain these patterns in the mitochondrial genome. PMID:22543055

  2. Spacer grid for fuel elements

    International Nuclear Information System (INIS)

    Hensolt, T.; Huenner, M.; Rau, P.; Veca, A.

    1978-01-01

    The spacer grid for fuel elements of a gas-cooled fast breeder reactor (but also for PWRs and BWRs) consists of a lattice field with dodecagonal meshes. These meshes are formed by three each adjacent hexagons grouped arround a central axis. The pairs of legs extending into the dodecagon and being staggered by 120 0 are designed as knubs with inclined abutting surfaces for the fuel rods. By this means there is formed a three-point bearing for centering the fuel rods. The spacer grid mentioned above is rough-worked from a single disc- resp. plate-shaped body (unfinished piece). (DG) [de

  3. Spacer grid for fuel elements

    International Nuclear Information System (INIS)

    Hensolt, T.; Huenner, M.; Rau, P.; Veca, A.

    1980-01-01

    The spacer grid for fuel elements of a gas-cooled fast breeder reactor (but also for PWRs and BWRs) consists of a lattice field with dodecagonal meshes. These meshes are formed by three each adjacent hexagons grouped arround a central axis. The pairs of legs extending into the dodecagon and being staggered by 120 are designed as knubs with inclined abutting surfaces for the fuel rods. By this means there is formed a three-point bearing for centering the fuel rods. The spacer grid mentioned above is rough-worked from a single disc- resp. plate-shaped body (unfinished piece). (orig.)

  4. PCR-Internal Transcribed Spacer (ITS) genes sequencing and ...

    African Journals Online (AJOL)

    Methods: DNA extraction, purification, amplification and sequencing of Internal Transcribed Spacer (ITS) genes were per- formed using ... Keywords: Internal transcribed spacer genes, phylogenetic, genetic relationship, clinical and environmental fungi, HIV-TB. ... Nigeria. An Ethical clearance was obtained from the Eth-.

  5. Chloroplast DNA analysis of Tunisian cork oak populations (Quercus suber L.): sequence variations and molecular evolution of the trnL (UAA)-trnF (GAA) region.

    Science.gov (United States)

    Abdessamad, A; Baraket, G; Sakka, H; Ammari, Y; Ksontini, M; Hannachi, A Salhi

    2016-10-24

    Sequences of the trnL-trnF spacer and combined trnL-trnF region in chloroplast DNA of cork oak (Quercus suber L.) were analyzed to detect polymorphisms and to elucidate molecular evolution and demographic history. The aligned sequences varied in length and nucleotide composition. The overall ratio of transition/transversion (ti/tv) of 0.724 for the intergenic spacer and 0.258 for the pooled sequences were estimated, and indicated that transversions are more frequent than transitions. The molecular evolution and demographic history of Q. suber were investigated. Neutrality tests (Tajima's D and Fu and Li) ruled out the null hypothesis of a strictly neutral model, and Fu's Fs and Ramos-Onsins and Rozas' R2 confirmed the recent expansion of cork oak trees, validating its persistency in North Africa since the last glaciation during the Quaternary. The observed uni-modal mismatch distribution and the Harpending's raggedness index confirmed the demographic history model for cork oak. A phylogenetic dendrogram showed that the distribution of Q. suber trees occurs independently of geographical origin, the relief of the population site, and the bioclimatic stages. The molecular history and cytoplasmic diversity suggest that in situ and ex situ conservation strategies can be recommended for preserving landscape value and facing predictable future climatic changes.

  6. Surface-Tethered Iterative Carbohydrate Synthesis (STICS): A spacer study

    Science.gov (United States)

    Ganesh, N. Vijaya; Fujikawa, Kohki; Tan, Yih Horng; Nigudkar, Swati S.

    2013-01-01

    Comparative study of STICS using HPLC-assisted experimental set-up clearly demonstrated benefits of using longer spacer-anchoring systems. The use of mixed self-assembled monolayers helps to provide the required space for glycosylation reaction around the immobilized glycosyl acceptor. Both extension of the spacer length and using mixed self-assembled monolayers help to promote reaction and the beneficial effects may include moving the glycosyl acceptor further out into solution and providing additional conformational flexibility. It is possible that surface-immobilized glycosyl acceptors with a longer spacer (C8-O-C8)-lipoic acid have a higher tendency to mimic a solution-phase reaction environment than that of acceptors with shorter spacers. PMID:23822088

  7. Histone and ribosomal RNA repetitive gene clusters of the boll weevil are linked in a tandem array.

    Science.gov (United States)

    Roehrdanz, R; Heilmann, L; Senechal, P; Sears, S; Evenson, P

    2010-08-01

    Histones are the major protein component of chromatin structure. The histone family is made up of a quintet of proteins, four core histones (H2A, H2B, H3 & H4) and the linker histones (H1). Spacers are found between the coding regions. Among insects this quintet of genes is usually clustered and the clusters are tandemly repeated. Ribosomal DNA contains a cluster of the rRNA sequences 18S, 5.8S and 28S. The rRNA genes are separated by the spacers ITS1, ITS2 and IGS. This cluster is also tandemly repeated. We found that the ribosomal RNA repeat unit of at least two species of Anthonomine weevils, Anthonomus grandis and Anthonomus texanus (Coleoptera: Curculionidae), is interspersed with a block containing the histone gene quintet. The histone genes are situated between the rRNA 18S and 28S genes in what is known as the intergenic spacer region (IGS). The complete reiterated Anthonomus grandis histone-ribosomal sequence is 16,248 bp.

  8. Dicty_cDB: Contig-U04396-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available rbcL intergenic spac... 44 5.3 1 ( DQ209842 ) Maxillaria lepidota atpB-rbcL inter...pacer, p... 44 5.3 1 ( DQ209656 ) Maxillaria molitor atpB-rbcL intergenic spacer, p... 44 5.3 1 ( DQ209650 ) Maxillaria lepidota...Q209568 ) Maxillaria cf. rufescens Whitten 1669 atpB-rbcL i... 44 5.3 1 ( DQ209566 ) Maxillaria aff. lepidota

  9. Study on natural convection in core barrel. Experimental and numerical results for band type spacer pads

    International Nuclear Information System (INIS)

    Hayashi, Kenji; Kawamata, Nobuhiro; Kamide, Hideki

    2003-03-01

    In a fast reactor an Inter-Wrapper Flow (IWF) is one of significant phenomena for decay heat removal under natural circulation condition, when a direct reactor auxiliary cooling system (DRACS) is adopted for decay heat removal system. Cold coolant provided by dipped heat exchangers (DHX) of DRACS can penetrate into the core barrel (region between the subassemblies) and it makes natural convection int he core barrel. Such IWF will depend on a spacer pad geometry of subassemblies. Water experiment, TRIF (Test Rig for Inter-wrapper Flow), was carried out for IWF in a reactor core. The test section modeled a 1/12th sector of the core and upper plenum of reactor vessel. Experimental parameters were the spacer pad geometry and flow path geometries connecting the upper plenum and core barrel. Numerical simulation using AQUA code was also performed to confirm applicability of a simulation method. An experimental series using a button type spacer pad had been carried out. Here a band type spacer pad was examined. Temperatures at subassembly wall were measured with parameter of the flow path geometries; one was a connection pipe between the upper plenum and core barrel and the other was flow hole in core former plates between the outermost subassemblies and the core barrel. It was found that these flow paths were effective to remove heat in the core in case of the band type spacer pad. A general purpose three dimensional analysis code, AQUA, was applied to the experimental analysis. Each subassembly and inter wrapper gap region were modeled by slab mesh geometry. Pressure loss coefficient at the pacer pad was set based on the geometry. The numerical simulation results were in good agreement with measured temperature profiles in the core. (author)

  10. Membrane with integrated spacer

    NARCIS (Netherlands)

    Balster, J.H.; Stamatialis, Dimitrios; Wessling, Matthias

    2010-01-01

    Many membrane processes are severely influenced by concentration polarisation. Turbulence promoting spacers placed in between the membranes can reduce the diffusional resistance of concentration polarisation by inducing additional mixing. Electrodialysis (ED) used for desalination suffers from

  11. A Study on Structural Strength of Irradiated Spacer Grid for PWR Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Y. G.; Baek, S. J.; Kim, D. S.; Yoo, B. O.; Ahn, S. B.; Chun, Y. B. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, J. I.; Kim, Y. H.; Lee, J. J. [KEPCO NF, Daejeon (Korea, Republic of)

    2014-10-15

    A fuel assembly consists of an array of fuel rods, spacer grids, guide thimbles, instrumentation tubes, and top and bottom nozzles. In PWR (Pressurized light Water Reactor) fuel assemblies, the spacer grids support the fuel rods by the friction forces between the fuel rods and springs/dimples. Under irradiation, the spacer grids supporting the fuel rods absorb vibration impacts due to the reactor coolant flow, and also bear static and dynamic loads during operation inside the nuclear reactor and transportation for spent fuel storage. Thus, it is important to understand the characteristics of deformation behavior and the change in structural strength of an irradiated spacer grid.. In the present study, the static compression test of a spacer grid was conducted to investigate the structural strength of the irradiated spacer grid in a hot cell at IMEF (Irradiated Materials Examination Facility) of KAERI. To evaluate the structural strength of an irradiated spacer grid, hot cell tests were carried out at IMEF of KAERI. The fuel assembly was dismantled and the irradiated spacer grid was obtained for the compression test. The apparatus for measuring the compression strength of the irradiated spacer grid was developed and installed successfully in the hot cell.

  12. Improved spacers for high temperature gas-cooled heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Nordstroem, L A [Swiss Federal Institute for Reactor Research, Wuerenlingen (Switzerland)

    1984-07-01

    Experimental and analytical investigations in the field of heat exchanger thermohydraulics have been performed at EIR for many years, Basic studies have been carried out on heat transfer and pressure loss for tube bundles of different geometries and tube surfaces. As a part of this overall R+D programme for heat exchangers, investigations have been carried out on spacer pressure loss in bundles with longitudinal flow. An analytical spacer pressure loss model was developed which could handle different types of subchannel within the bundle. The model has been evaluated against experiments, using about 25 spacers of widely differing geometries. In a gas-cooled reactor it is important to keep the pressure loss over the primary circuit heat exchangers to a minimum. In exchangers with grid spacers these contribute a significant proportion of the overall bundle losses. For example, in the HHT Recuperator, with a shell-side pressure loss of 3.5 % of the inlet pressure, the spacers cause about one half of this loss. Reducing the loss to, say, 2.5 % results in an overall increase in plant efficiency by more than 1 % - a significant improvement Preliminary analysis identified 5 geometries in particular which were chosen for experimental evaluation as part of a joint project with the SULZER Company, to develop a low pressure-loss spacer for HHT heat exchangers (longitudinal counter-flow He/He and He/H{sub 2}O designs). The aim of the tests was to verify the low pressure-loss characteristics of these spacer grid types, as well as the quality of the results calculated by the computer code analytical model. The experimental and analytical results are compared in this report.

  13. In vitro microbiologic evaluation of PTFE and cotton as spacer materials.

    Science.gov (United States)

    Paranjpe, Avina; Jain, Sumita; Alibhai, Karim J; Wadhwani, Chandur P; Darveau, Richard P; Johnson, James D

    2012-09-01

    To microbiologically evaluate the efficacy of cotton and polytetrafluoroethylene (PTFE) tape used as spacer materials. Twenty-six extracted human molars were restored using either cotton or PTFE tape as spacers under a standardized provisional restorative material (Cavit). The teeth were incubated for 7 days in a culture of Streptococcus gordonii or in liquid media alone. The spacers were removed and tested for bacterial contamination. The access cavities were also evaluated for bacterial contamination. Nine of 10 teeth with cotton spacers and one of 10 teeth with PTFE spacers were positive for S gordonii growth. The nine teeth in the cotton group also showed contamination of the access cavities. Even under optimal conditions, cotton spacers may cause leakage into the access cavities. Cotton fibers may serve as a route for bacterial contamination of the access cavities and root canal space. In contrast, PTFE tape did not provide an avenue for bacterial contamination.

  14. The CRISPR Spacer Space Is Dominated by Sequences from Species-Specific Mobilomes.

    Science.gov (United States)

    Shmakov, Sergey A; Sitnik, Vassilii; Makarova, Kira S; Wolf, Yuri I; Severinov, Konstantin V; Koonin, Eugene V

    2017-09-19

    Clustered regularly interspaced short palindromic repeats and CRISPR-associated protein (CRISPR-Cas) systems store the memory of past encounters with foreign DNA in unique spacers that are inserted between direct repeats in CRISPR arrays. For only a small fraction of the spacers, homologous sequences, called protospacers, are detectable in viral, plasmid, and microbial genomes. The rest of the spacers remain the CRISPR "dark matter." We performed a comprehensive analysis of the spacers from all CRISPR- cas loci identified in bacterial and archaeal genomes, and we found that, depending on the CRISPR-Cas subtype and the prokaryotic phylum, protospacers were detectable for 1% to about 19% of the spacers (~7% global average). Among the detected protospacers, the majority, typically 80 to 90%, originated from viral genomes, including proviruses, and among the rest, the most common source was genes that are integrated into microbial chromosomes but are involved in plasmid conjugation or replication. Thus, almost all spacers with identifiable protospacers target mobile genetic elements (MGE). The GC content, as well as dinucleotide and tetranucleotide compositions, of microbial genomes, their spacer complements, and the cognate viral genomes showed a nearly perfect correlation and were almost identical. Given the near absence of self-targeting spacers, these findings are most compatible with the possibility that the spacers, including the dark matter, are derived almost completely from the species-specific microbial mobilomes. IMPORTANCE The principal function of CRISPR-Cas systems is thought to be protection of bacteria and archaea against viruses and other parasitic genetic elements. The CRISPR defense function is mediated by sequences from parasitic elements, known as spacers, that are inserted into CRISPR arrays and then transcribed and employed as guides to identify and inactivate the cognate parasitic genomes. However, only a small fraction of the CRISPR spacers

  15. Eddy current monitoring of spacers in coolant channel assemblies of nuclear reactor

    International Nuclear Information System (INIS)

    Bhole, V.M.; Rastogi, P.K.; Kulkarni, P.G.; Vijayaraghavan, R.

    1993-01-01

    An eddy current testing method has been standardised for monitoring spacer springs which are used in coolant channel assemblies of pressurised heavy water nuclear reactors (PHWRs). The standard bobbin coil probe used for monitoring the spacer spring detects only the location but does not monitor the tilt orientation and tilt angle of a tilted spacer spring. The knowledge of location along with the tilt orientation of the spacer spring greatly improves the performance of repositioning methods. A modified probe with angular windings has been developed in laboratory tests for monitoring the location as well as the tilt orientation of the spacer springs. Experimental results are presented showing excellent performance of the modified probe in monitoring the exact location as well as tilt orientation of a spacer spring. The modified probe has also been used successfully in the field during repositioning of spacer springs in PHWRs before commissioning. (Author)

  16. Extensive 5.8S nrDNA polymorphism in Mammillaria (Cactaceae) with special reference to the identification of pseudogenic internal transcribed spacer regions.

    Science.gov (United States)

    Harpke, Doerte; Peterson, Angela

    2008-05-01

    The internal transcribed spacer (ITS) region (ITS1, 5.8S rDNA, ITS2) represents the most widely applied nuclear marker in eukaryotic phylogenetics. Although this region has been assumed to evolve in concert, the number of investigations revealing high degrees of intra-individual polymorphism connected with the presence of pseudogenes has risen. The 5.8S rDNA is the most important diagnostic marker for functionality of the ITS region. In Mammillaria, intra-individual 5.8S rDNA polymorphisms of up to 36% and up to nine different types have been found. Twenty-eight of 30 cloned genomic Mammillaria sequences were identified as putative pseudogenes. For the identification of pseudogenic ITS regions, in addition to formal tests based on substitution rates, we attempted to focus on functional features of the 5.8S rDNA (5.8S motif, secondary structure). The importance of functional data for the identification of pseudogenes is outlined and discussed. The identification of pseudogenes is essential, because they may cause erroneous phylogenies and taxonomic problems.

  17. Buckling behavior analysis of spacer grid by lateral impact load

    International Nuclear Information System (INIS)

    Yoon, Kyung Ho; Kang, Heung Seok; Kim, Hyung Kyu; Song, Kee Nam

    2000-05-01

    The spacer grid is one of the main structural components in the fuel assembly, Which supports the fuel rods, guides cooling water, and protects the system from an external impact load, such as earthquakes. Therefore, the mechanical and structural properties of the spacer grids must be extensively examined while designing it. In this report, free fall type shock tests on the several kinds of the specimens of the spacer grids were also carried out in order to compare the results among the candidate grids. A free fall carriage on the specimen accomplishes the test. In addition to this, a finite element method for predicting the critical impact strength of the spacer grids is described. FE method on the buckling behavior of the spacer grids are performed for a various array of sizes of the grids considering that the spacer grid is an assembled structure with thin-walled plates and imposing proper boundary conditions by nonlinear dynamic impact analysis using ABAQUS/explicit code. The simulated results results also similarly predicted the local buckling phenomena and were found to give good correspondence with the shock test results

  18. Trichosporon inkin: an uncommon agent of scalp white piedra. Report of four cases in Brazilian children.

    Science.gov (United States)

    Fischman, Olga; Bezerra, Fabiane Castilho; Francisco, Elaine Cristina; da Silva, Flávia Cristina; Nishikaku, Angela Satie; Cavalcanti, Sarah Desirée Barbosa; de Azevedo Melo, Analy Salles; Bentubo, Henri Donnarumma Levy; Petri, Valéria

    2014-08-01

    We report four cases of scalp white piedra (SWP) in Brazilian female children. Morphological and physiological approaches gave inconsistent results for identifying Trichosporon to species level, while the sequencing of the intergenic spacer 1 region of ribosomal DNA accurately identified the agent of SWP as T. inkin. These cases emphasize the occurrence of this species causing this type of infection. The molecular identification of the suspected agent is needed for appropriate epidemiological surveillance of superficial mycoses caused by Trichosporon species.

  19. Numerical analysis of the spacer grids' compression strength

    International Nuclear Information System (INIS)

    Schettino, C.F.M.; Gouvea, J.P.; Medeiros, N.

    2013-01-01

    Among the components of the fuel assembly, the spacer grids play an important structural role during the energy generation process, mainly for their requirement to have enough structural strength to withstand lateral impact loads, due to fuel assembly shipping/handling and due to forces outcome from postulated accidents (earthquake and LOCA). This requirement ensures a proper geometry for cooling and for guide thimble straightness in the fuel assembly. In this way, the understanding of the macroscopic mechanical behavior of this component becomes essential even to any subsequent geometrical modifications to optimize the flue assemblies' structural behavior. In the present work, three-dimensional finite element models destined to provide consistent predictions of 16X16-type spacer grids lateral strength were proposed. Firstly, buckling tests based on results available in the literature were performed to establish a methodology for spacer grid finite element-based modeling. The, by considering a spacer grid interesting geometry and some possible variations associated to its fabrication, tolerance, the proposed numerical models were submitted to compression conditions to calculate the buckling force. Also, these models were validated for comparison with experimental buckling load results. Comparison of buckling predictions combined to observations of actual and simulated deformed spacer grids geometries permitted to verify the consistency and applicability of the proposed models. Thus, these numerical results show a good agreement between the and the experimental results. (author)

  20. Similar Ratios of Introns to Intergenic Sequence across Animal Genomes.

    Science.gov (United States)

    Francis, Warren R; Wörheide, Gert

    2017-06-01

    One central goal of genome biology is to understand how the usage of the genome differs between organisms. Our knowledge of genome composition, needed for downstream inferences, is critically dependent on gene annotations, yet problems associated with gene annotation and assembly errors are usually ignored in comparative genomics. Here, we analyze the genomes of 68 species across 12 animal phyla and some single-cell eukaryotes for general trends in genome composition and transcription, taking into account problems of gene annotation. We show that, regardless of genome size, the ratio of introns to intergenic sequence is comparable across essentially all animals, with nearly all deviations dominated by increased intergenic sequence. Genomes of model organisms have ratios much closer to 1:1, suggesting that the majority of published genomes of nonmodel organisms are underannotated and consequently omit substantial numbers of genes, with likely negative impact on evolutionary interpretations. Finally, our results also indicate that most animals transcribe half or more of their genomes arguing against differences in genome usage between animal groups, and also suggesting that the transcribed portion is more dependent on genome size than previously thought. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  1. How type II CRISPR-Cas establish immunity through Cas1-Cas2-mediated spacer integration.

    Science.gov (United States)

    Xiao, Yibei; Ng, Sherwin; Nam, Ki Hyun; Ke, Ailong

    2017-10-05

    CRISPR (clustered regularly interspaced short palindromic repeats) and the nearby Cas (CRISPR-associated) operon establish an RNA-based adaptive immunity system in prokaryotes. Molecular memory is created when a short foreign DNA-derived prespacer is integrated into the CRISPR array as a new spacer. Whereas the RNA-guided CRISPR interference mechanism varies widely among CRISPR-Cas systems, the spacer integration mechanism is essentially identical. The conserved Cas1 and Cas2 proteins form an integrase complex consisting of two distal Cas1 dimers bridged by a Cas2 dimer. The prespacer is bound by Cas1-Cas2 as a dual-forked DNA, and the terminal 3'-OH of each 3' overhang serves as an attacking nucleophile during integration. The prespacer is preferentially integrated into the leader-proximal region of the CRISPR array, guided by the leader sequence and a pair of inverted repeats inside the CRISPR repeat. Spacer integration in the well-studied Escherichia coli type I-E CRISPR system also relies on the bacterial integration host factor. In type II-A CRISPR, however, Cas1-Cas2 alone integrates spacers efficiently in vitro; other Cas proteins (such as Cas9 and Csn2) have accessory roles in the biogenesis phase of prespacers. Here we present four structural snapshots from the type II-A system of Enterococcus faecalis Cas1 and Cas2 during spacer integration. Enterococcus faecalis Cas1-Cas2 selectively binds to a splayed 30-base-pair prespacer bearing 4-nucleotide 3' overhangs. Three molecular events take place upon encountering a target: first, the Cas1-Cas2-prespacer complex searches for half-sites stochastically, then it preferentially interacts with the leader-side CRISPR repeat, and finally, it catalyses a nucleophilic attack that connects one strand of the leader-proximal repeat to the prespacer 3' overhang. Recognition of the spacer half-site requires DNA bending and leads to full integration. We derive a mechanistic framework to explain the stepwise spacer

  2. Antibiotic-impregnated articulating cement spacer for infected total knee arthroplasty

    Directory of Open Access Journals (Sweden)

    Parag Garg

    2011-01-01

    Full Text Available Background : Standard treatment of chronic infected total knee arthroplasty (TKA is a two-stage revision, the first step being placement of an antibiotic-impregnated cement spacer. Here we describe the results of a new technique (modification of the Goldstien′s technique for intraoperative manufacture of a customized articulating spacer at minimal cost and with relatively good conformity and longevity. Materials and Methods : Thirty-six infected knees underwent this procedure from June 2002 to May 2007. The technique consists of using the freshened femur and tibia interface as molds wrapped in a tin foil for manufacturing the two components of the spacer with antibiotic-impregnated methyl methycrylate cement. We used the spacer and the femoral component of the trial set of a TKA system to mold them to perfect articulation. We also reinforced the spacer with a K-wire scaffold to prevent fracture of the cement mantle in the last 21 cases. Results : All 36 knees showed excellent results in terms of infection control, mobility, and stability. There was significant improvement in the WOMAC and Knee Society Scores (20 and 39 points respectively. There were two fractures of the spacers in the initial 15 cases that did not have K-wire scaffolding but none in the last 21 that had reinforcement. Conclusion : This technique provides a more conforming spacer, with good range of motion and stability. The reinforcement helps in preventing the fracture of the cement mantle and is cost effective.

  3. Development and characterization of 3D-printed feed spacers for spiral wound membrane systems

    KAUST Repository

    Siddiqui, Amber

    2016-01-02

    Feed spacers are important for the impact of biofouling on the performance of spiral-wound reverse osmosis (RO) and nanofiltration (NF) membrane systems. The objective of this study was to propose a strategy for developing, characterizing, and testing of feed spacers by numerical modeling, three-dimensional (3D) printing of feed spacers and experimental membrane fouling simulator (MFS) studies. The results of numerical modeling on the hydraulic behavior of various feed spacer geometries suggested that the impact of spacers on hydraulics and biofouling can be improved. A good agreement was found for the modeled and measured relationship between linear flow velocity and pressure drop for feed spacers with the same geometry, indicating that modeling can serve as first step in spacer characterization. An experimental comparison study of a feed spacer currently applied in practice and a 3D printed feed spacer with the same geometry showed (i) similar hydraulic behavior, (ii) similar pressure drop development with time and (iii) similar biomass accumulation during MFS biofouling studies, indicating that 3D printing technology is an alternative strategy for development of thin feed spacers with a complex geometry. Based on the numerical modeling results, a modified feed spacer with low pressure drop was selected for 3D printing. The comparison study of the feed spacer from practice and the modified geometry 3D printed feed spacer established that the 3D printed spacer had (i) a lower pressure drop during hydraulic testing, (ii) a lower pressure drop increase in time with the same accumulated biomass amount, indicating that modifying feed spacer geometries can reduce the impact of accumulated biomass on membrane performance. The combination of numerical modeling of feed spacers and experimental testing of 3D printed feed spacers is a promising strategy (rapid, low cost and representative) to develop advanced feed spacers aiming to reduce the impact of biofilm formation on

  4. (ISSR) and internal transcribed spacer

    African Journals Online (AJOL)

    Cladistic relationships within the genus Cinnamomum (Lauraceae) in Taiwan based on analysis of leaf morphology and inter-simple sequence repeat (ISSR) and internal transcribed spacer (ITS) molecular markers.

  5. Orthognathic model surgery with LEGO key-spacer.

    Science.gov (United States)

    Tsang, Alfred Chee-Ching; Lee, Alfred Siu Hong; Li, Wai Keung

    2013-12-01

    A new technique of model surgery using LEGO plates as key-spacers is described. This technique requires less time to set up compared with the conventional plaster model method. It also retains the preoperative setup with the same set of models. Movement of the segments can be measured and examined in detail with LEGO key-spacers. Copyright © 2013 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  6. Hypervariability of ribosomal DNA at multiple chromosomal sites in lake trout (Salvelinus namaycush).

    Science.gov (United States)

    Zhuo, L; Reed, K M; Phillips, R B

    1995-06-01

    Variation in the intergenic spacer (IGS) of the ribosomal DNA (rDNA) of lake trout (Salvelinus namaycush) was examined. Digestion of genomic DNA with restriction enzymes showed that almost every individual had a unique combination of length variants with most of this variation occurring within rather than between populations. Sequence analysis of a 2.3 kilobase (kb) EcoRI-DraI fragment spanning the 3' end of the 28S coding region and approximately 1.8 kb of the IGS revealed two blocks of repetitive DNA. Putative transcriptional termination sites were found approximately 220 bases (b) downstream from the end of the 28S coding region. Comparison of the 2.3-kb fragments with two longer (3.1 kb) fragments showed that the major difference in length resulted from variation in the number of short (89 b) repeats located 3' to the putative terminator. Repeat units within a single nucleolus organizer region (NOR) appeared relatively homogeneous and genetic analysis found variants to be stably inherited. A comparison of the number of spacer-length variants with the number of NORs found that the number of length variants per individual was always less than the number of NORs. Examination of spacer variants in five populations showed that populations with more NORs had more spacer variants, indicating that variants are present at different rDNA sites on nonhomologous chromosomes.

  7. System for measuring spacer pin pitch in a nuclear fuel assembly

    International Nuclear Information System (INIS)

    Isono, Kenji; Tateishi, Yoshinori; Mano, Tadashi.

    1975-01-01

    Object: To reduce the period for discriminating whether or not spacer pin pitch is satisfactory by simultaneously inserting a number of reference rods into a nuclear fuel assembly spacer ring element of a reactor and arranging them such that they can be simultaneously withdrawn to simplify the withdrawing operation. Structure: A spacer provided with a ring element which clamps a nuclear fuel element is supported on a spacer support with a rod secured to the support as a guide and is secured to the support by securing means. A vertically movable structure with a reference rod provided upright and thru-holes formed in two support plates provided in the same row as the spacer ring element is operated by a fluid pressure mechanism to simultaneously insert the reference rod into the spacer ring element. The reference rod is mounted in support plates via ball bearings such that it is slightly movable in the horizontal direction, and it is aligned with respect to the core of the ring element. The intercore distance of the reference rod is measured with the reference rod inserted in the ring element, thereby measuring the space pin pitch. From the results of measurement, discrimination as to whether the spacer is satisfactory or not is made. (Kamimura, M.)

  8. Hydrogel Spacer Prospective Multicenter Randomized Controlled Pivotal Trial: Dosimetric and Clinical Effects of Perirectal Spacer Application in Men Undergoing Prostate Image Guided Intensity Modulated Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Mariados, Neil, E-mail: nmariados@ampofny.com [Associated Medical Professionals of New York, Syracuse, New York (United States); Sylvester, John [21st Century Oncology, East Bradenton, Florida (United States); Shah, Dhiren [Western New York Urology Associates, Cancer Care of WNY, Cheektowaga, New York (United States); Karsh, Lawrence [The Urology Center of Colorado, Denver, Colorado (United States); Hudes, Richard [Chesapeake Urology Research Associates, The Prostate Center, Owings Mills, Maryland (United States); Beyer, David [Arizona Oncology Services Foundation, Phoenix, Arizona (United States); Kurtzman, Steven [Urological Surgeons of Northern California, Campbell, California (United States); Bogart, Jeffrey [The Research Foundation of State University of New York, SUNY Upstate Medical University, Syracuse, New York (United States); Hsi, R. Alex [Peninsula Cancer Center, Poulsbo, Washington (United States); Kos, Michael [Urology Nevada, Reno, Nevada (United States); Ellis, Rodney [University Hospitals Case Medical Center, Cleveland, Ohio (United States); Logsdon, Mark [Sutter Health Sacramento Sierra Region, Sutter Institute for Medical Research, Sacramento, California (United States); Zimberg, Shawn [Advanced Radiation Centers of New York, Lake Success, New York (United States); Forsythe, Kevin [Oregon Urology Institute, Springfield, Oregon (United States); Zhang, Hong [University of Rochester, Rochester, New York (United States); Soffen, Edward [CentraState Medical Center, Freehold, New Jersey (United States); Francke, Patrick [Carolina Regional Cancer Center, 21st Century Oncology, Myrtle Beach, South Carolina (United States); Mantz, Constantine [21st Century Oncology, Fort Meyers, Florida (United States); Rossi, Peter [Emory University, Atlanta, Georgia (United States); DeWeese, Theodore [The Johns Hopkins University, Baltimore, Maryland (United States); and others

    2015-08-01

    Purpose: Perirectal spacing, whereby biomaterials are placed between the prostate and rectum, shows promise in reducing rectal dose during prostate cancer radiation therapy. A prospective multicenter randomized controlled pivotal trial was performed to assess outcomes following absorbable spacer (SpaceOAR system) implantation. Methods and Materials: Overall, 222 patients with clinical stage T1 or T2 prostate cancer underwent computed tomography (CT) and magnetic resonance imaging (MRI) scans for treatment planning, followed with fiducial marker placement, and were randomized to receive spacer injection or no injection (control). Patients received postprocedure CT and MRI planning scans and underwent image guided intensity modulated radiation therapy (79.2 Gy in 1.8-Gy fractions). Spacer safety and impact on rectal irradiation, toxicity, and quality of life were assessed throughout 15 months. Results: Spacer application was rated as “easy” or “very easy” 98.7% of the time, with a 99% hydrogel placement success rate. Perirectal spaces were 12.6 ± 3.9 mm and 1.6 ± 2.0 mm in the spacer and control groups, respectively. There were no device-related adverse events, rectal perforations, serious bleeding, or infections within either group. Pre-to postspacer plans had a significant reduction in mean rectal V70 (12.4% to 3.3%, P<.0001). Overall acute rectal adverse event rates were similar between groups, with fewer spacer patients experiencing rectal pain (P=.02). A significant reduction in late (3-15 months) rectal toxicity severity in the spacer group was observed (P=.04), with a 2.0% and 7.0% late rectal toxicity incidence in the spacer and control groups, respectively. There was no late rectal toxicity greater than grade 1 in the spacer group. At 15 months 11.6% and 21.4% of spacer and control patients, respectively, experienced 10-point declines in bowel quality of life. MRI scans at 12 months verified spacer absorption. Conclusions: Spacer

  9. Molecular analysis of fungal populations in patients with oral candidiasis using internal transcribed spacer region.

    Science.gov (United States)

    Ieda, Shinsuke; Moriyama, Masafumi; Takeshita, Toru; Takashita, Toru; Maehara, Takashi; Imabayashi, Yumi; Shinozaki, Shoichi; Tanaka, Akihiko; Hayashida, Jun-Nosuke; Furukawa, Sachiko; Ohta, Miho; Yamashita, Yoshihisa; Nakamura, Seiji

    2014-01-01

    Oral candidiasis is closely associated with changes in the oral fungal flora and is caused primarily by Candida albicans. Conventional methods of fungal culture are time-consuming and not always conclusive. However, molecular genetic analysis of internal transcribed spacer (ITS) regions of fungal rRNA is rapid, reproducible and simple to perform. In this study we examined the fungal flora in patients with oral candidiasis and investigated changes in the flora after antifungal treatment using length heterogeneity-polymerization chain reaction (LH-PCR) analysis of ITS regions. Fifty-two patients with pseudomembranous oral candidiasis (POC) and 30 healthy controls were included in the study. Fungal DNA from oral rinse was examined for fungal species diversity by LH-PCR. Fungal populations were quantified by real-time PCR and previously-unidentified signals were confirmed by nucleotide sequencing. Relationships between the oral fungal flora and treatment-resistant factors were also examined. POC patients showed significantly more fungal species and a greater density of fungi than control individuals. Sixteen fungi were newly identified. The fungal populations from both groups were composed predominantly of C. albicans, though the ratio of C. dubliniensis was significantly higher in POC patients than in controls. The diversity and density of fungi were significantly reduced after treatment. Furthermore, fungal diversity and the proportion of C. dubliniensis were positively correlated with treatment duration. These results suggest that C. dubliniensis and high fungal flora diversity might be involved in the pathogenesis of oral candidiasis. We therefore conclude that LH-PCR is a useful technique for diagnosing and assessing the severity of oral candidal infection.

  10. A Sequence-Specific Interaction between the Saccharomyces cerevisiae rRNA Gene Repeats and a Locus Encoding an RNA Polymerase I Subunit Affects Ribosomal DNA Stability

    Science.gov (United States)

    Cahyani, Inswasti; Cridge, Andrew G.; Engelke, David R.; Ganley, Austen R. D.

    2014-01-01

    The spatial organization of eukaryotic genomes is linked to their functions. However, how individual features of the global spatial structure contribute to nuclear function remains largely unknown. We previously identified a high-frequency interchromosomal interaction within the Saccharomyces cerevisiae genome that occurs between the intergenic spacer of the ribosomal DNA (rDNA) repeats and the intergenic sequence between the locus encoding the second largest RNA polymerase I subunit and a lysine tRNA gene [i.e., RPA135-tK(CUU)P]. Here, we used quantitative chromosome conformation capture in combination with replacement mapping to identify a 75-bp sequence within the RPA135-tK(CUU)P intergenic region that is involved in the interaction. We demonstrate that the RPA135-IGS1 interaction is dependent on the rDNA copy number and the Msn2 protein. Surprisingly, we found that the interaction does not govern RPA135 transcription. Instead, replacement of a 605-bp region within the RPA135-tK(CUU)P intergenic region results in a reduction in the RPA135-IGS1 interaction level and fluctuations in rDNA copy number. We conclude that the chromosomal interaction that occurs between the RPA135-tK(CUU)P and rDNA IGS1 loci stabilizes rDNA repeat number and contributes to the maintenance of nucleolar stability. Our results provide evidence that the DNA loci involved in chromosomal interactions are composite elements, sections of which function in stabilizing the interaction or mediating a functional outcome. PMID:25421713

  11. Biofouling Control in Spiral-Wound Membrane Systems: Impact of Feed Spacer Modification and Biocides

    KAUST Repository

    Siddiqui, Amber

    2016-12-01

    High-quality drinking water can be produced with membrane-based filtration processes like reverse osmosis and nanofiltration. One of the major problems in these membrane systems is biofouling that reduces the membrane performance, increasing operational costs. Current biofouling control strategies such as pre-treatment, membrane modification, and chemical cleaning are not sufficient in all cases. Feed spacers are thin (0.8 mm), complex geometry meshes that separate membranes in a module. The main objective of this research was to evaluate whether feed spacer modification is a suitable strategy to control biofouling. Membrane fouling simulator studies with six feed spacers showed differences in biofouled spacer performance, concluding that (i) spacer geometry influences biofouling impact and (ii) biofouling studies are essential for evaluation of spacer biofouling impact. Computed tomography (CT) was found as a suitable technique to obtain three-dimensional (3D) measurements of spacers, enabling more representative mathematical modeling of hydraulic behavior of spacers in membrane systems. A strategy for developing, characterizing, and testing of spacers by numerical modeling, 3D printing of spacers and experimental membrane fouling simulator studies was developed. The combination of modeling and experimental testing of 3D printed spacers is a promising strategy to develop advanced spacers aiming to reduce the impact of biofilm formation on membrane performance and to improve the cleanability of spiral-wound membrane systems.

  12. Ertapenem Articulating Spacer for the Treatment of Polymicrobial Total Knee Arthroplasty Infection

    Directory of Open Access Journals (Sweden)

    Dragan Radoicic

    2016-01-01

    Full Text Available Introduction. Periprosthetic joint infections (PJIs are the primary cause of early failure of the total knee arthroplasty (TKA. Polymicrobial TKA infections are often associated with a higher risk of treatment failure. The aim of the study was to assess the efficacy of ertapenem loaded spacers in the treatment of polymicrobial PJI. Methods. There were 18 patients enrolled; nine patients with polymicrobial PJI treated with ertapenem loaded articulating spacers were compared to the group of 9 patients treated with vancomycin or ceftazidime loaded spacers. Results. Successful reimplantation with revision implants was possible in 66.67%. Ertapenem spacers were used in 6 cases in primary two-stage procedure and in 3 cases in secondary spacer exchange. Successful infection eradication was achieved in all cases; final reimplantation with revision knee arthroplasty implants was possible in 6 cases. Conclusion. Ertapenem can be successfully used as antimicrobial addition to the cement spacers in two-stage revision treatment of polymicrobial PJIs. However, this type of spacer may also be useful in the treatment of infections caused by monomicrobial extended spectrum beta-lactamases producing gram-negative bacilli. Further clinical studies are required to evaluate the efficacy and safety of ertapenem spacers in the treatment of polymicrobial and monomicrobial PJIs.

  13. Experimental investigation of turbulent flow through spacer grids in fuel rod bundles

    International Nuclear Information System (INIS)

    Caraghiaur, Diana; Anglart, Henryk; Frid, Wiktor

    2009-01-01

    This paper contains experimental data of pressure, velocity and turbulence intensity in a 24-rod fuel bundle with spacer grids. Detailed pressure measurements inside the spacer grid have been obtained by use of a sliding pressure-sensing rod. Laser Doppler Velocimetry technique was used to measure the local axial velocity and its fluctuating component upstream and downstream of the spacer grid in sub-channels with different blockage ratios. The measurements show a changing pattern in function of radial position in the cross-section of the fuel bundle. For sub-channels close to the box wall, the turbulence intensity suddenly increases just downstream of the spacer and then gradually decays. In inner sub-channels, however, the turbulence intensity downstream of the spacer decreases below its upstream value and then gradually increases until it reaches the maximum value at approximately two spacer heights. The present study reveals that spacer effects, such as local pressure distribution and turbulence intensity enhancement, not only depend exclusively on the local geometry details, but also on the location in the cross-section of the rod bundle.

  14. Experimental investigation of turbulent flow through spacer grids in fuel rod bundles

    Energy Technology Data Exchange (ETDEWEB)

    Caraghiaur, Diana [Royal Institute of Technology, Division of Nuclear Reactor Technology, Department of Physics, School of Engineering Sciences, AlbaNova University Center, SE-106 91 Stockholm (Sweden)], E-mail: dianac@kth.se; Anglart, Henryk [Royal Institute of Technology, Division of Nuclear Reactor Technology, Department of Physics, School of Engineering Sciences, AlbaNova University Center, SE-106 91 Stockholm (Sweden); Frid, Wiktor [Swedish Radiation Safety Authority, Reactor Technology and Structural Integrity, SE-171 16 Stockholm (Sweden)

    2009-10-15

    This paper contains experimental data of pressure, velocity and turbulence intensity in a 24-rod fuel bundle with spacer grids. Detailed pressure measurements inside the spacer grid have been obtained by use of a sliding pressure-sensing rod. Laser Doppler Velocimetry technique was used to measure the local axial velocity and its fluctuating component upstream and downstream of the spacer grid in sub-channels with different blockage ratios. The measurements show a changing pattern in function of radial position in the cross-section of the fuel bundle. For sub-channels close to the box wall, the turbulence intensity suddenly increases just downstream of the spacer and then gradually decays. In inner sub-channels, however, the turbulence intensity downstream of the spacer decreases below its upstream value and then gradually increases until it reaches the maximum value at approximately two spacer heights. The present study reveals that spacer effects, such as local pressure distribution and turbulence intensity enhancement, not only depend exclusively on the local geometry details, but also on the location in the cross-section of the rod bundle.

  15. Identification of pathogenic Nocardia species by reverse line blot hybridization targeting the 16S rRNA and 16S-23S rRNA gene spacer regions.

    Science.gov (United States)

    Xiao, Meng; Kong, Fanrong; Sorrell, Tania C; Cao, Yongyan; Lee, Ok Cha; Liu, Ying; Sintchenko, Vitali; Chen, Sharon C A

    2010-02-01

    Although 16S rRNA gene sequence analysis is employed most often for the definitive identification of Nocardia species, alternate molecular methods and polymorphisms in other gene targets have also enabled species determinations. We evaluated a combined Nocardia PCR-based reverse line blot (RLB) hybridization assay based on 16S and 16S-23S rRNA gene spacer region polymorphisms to identify 12 American Type Culture Collection and 123 clinical Nocardia isolates representing 14 species; results were compared with results from 16S rRNA gene sequencing. Thirteen 16S rRNA gene-based (two group-specific and 11 species-specific) and five 16S-23S spacer-targeted (two taxon-specific and three species-specific) probes were utilized. 16S rRNA gene-based probes correctly identified 124 of 135 isolates (sensitivity, 92%) but were unable to identify Nocardia paucivorans strains (n = 10 strains) and a Nocardia asteroides isolate with a novel 16S rRNA gene sequence. Nocardia farcinica and Nocardia cyriacigeorgica strains were identified by the sequential use of an N. farcinica-"negative" probe and a combined N. farcinica/N. cyriacigeorgica probe. The assay specificity was high (99%) except for weak cross-reactivity between the Nocardia brasiliensis probe with the Nocardia thailandica DNA product; however, cross-hybridization with closely related nontarget species may occur. The incorporation of 16S-23S rRNA gene spacer-based probes enabled the identification of all N. paucivorans strains. The overall sensitivity using both probe sets was >99%. Both N. farcinica-specific 16S-23S rRNA gene spacer-directed probes were required to identify all N. farcinica stains by using this probe set. The study demonstrates the utility of a combined PCR/RLB assay for the identification of clinically relevant Nocardia species and its potential for studying subtypes of N. farcinica. Where species assignment is ambiguous or not possible, 16S rRNA gene sequencing is recommended.

  16. Grid spacers for use in a nuclear fuel assembly

    International Nuclear Information System (INIS)

    Kuwako, Akira.

    1987-01-01

    Purpose: To obtain spacers capable of reducing the pressure loss by enlarging coolant flow channels when the fuel temperature is high, while capable of reliably maintaining the fuel pins with no vibrations when the fuel temperature is low. Constitution: This invention concerns grid spacers for constituting fuel assemblies for use in water cooled reactors. Memory shape alloys are disposed at least a portion of a spacer element that takes such a shape as urging the pin when the fuel temperature is low, while enlarging the coolant flow channel to reduce the pressure loss when the fuel temperature is high. (Ikeda, J.)

  17. Computer-Aided Design Method of Warp-Knitted Jacquard Spacer Fabrics

    Directory of Open Access Journals (Sweden)

    Li Xinxin

    2016-06-01

    Full Text Available Based on a further study on knitting and jacquard principles, this paper presents a mathematical design model to make computer-aided design of warp-knitted jacquard spacer fabrics more efficient. The mathematical model with matrix method employs three essential elements of chain notation, threading and Jacquard designing. With this model, the processing to design warp-knitted jacquard spacer fabrics with CAD software is also introduced. In this study, the sports shoes which have separated functional areas according to the feet structure and characteristics of movement are analysed. The results show the different patterns on Jacquard spacer fabrics that are seamlessly stitched with jacquard technics. The computer-aided design method of warp-knitted jacquard spacer fabrics is efficient and simple.

  18. The influence of the preliminary garter spring spacer simulator clamping force in the pressure tube spacer -calandria tube hook-up simulator aging behaviour

    International Nuclear Information System (INIS)

    Gyongyosi, T.; Deloreanu, G.; Puiu, D.; Corbescu, B.; Anghel, N.; Dinu, E.

    2016-01-01

    The garter spring spacer is a specially constructed torsion spring used to fit-out the CANDU 6 fuel channel. The pressure tube ageing decreases the gap to the calandria tube. Continuous gap decrease directly affects the garter spring spacers behavior during fuel channel assembly operation. The preliminary clamping force value of the garter spring spacer assembly is important for its ageing behavior. This paper briefly describes the experimental technological facilities used for conducted the experiments and highlights some of the important moments during an experiment carried out in laboratory conditions, without using pressurized boiled water and irradiation working conditions. The results analysis and some conclusions are outlined at the end, pointing out that a garter spring spacer preliminary clamping force increase reduces the vibration response signal amplitude, and does not lead to its relaxation. The paper is dedicated to specialists working in research and technological engineering. (authors)

  19. Rapid identification of probiotic Lactobacillus species by multiplex PCR using species-specific primers based on the region extending from 16S rRNA through 23S rRNA.

    Science.gov (United States)

    Kwon, Hyuk-Sang; Yang, Eun-Hee; Yeon, Seung-Woo; Kang, Byoung-Hwa; Kim, Tae-Yong

    2004-10-15

    This study aimed to develop a novel multiplex polymerase chain reaction (PCR) primer set for the identification of seven probiotic Lactobacillus species such as Lactobacillus acidophilus, Lactobacillus delbrueckii, Lactobacillus casei, Lactobacillus gasseri, Lactobacillus plantarum, Lactobacillus reuteri and Lactobacillus rhamnosus. The primer set, comprising of seven specific and two conserved primers, was derived from the integrated sequences of 16S and 23S rRNA genes and their rRNA intergenic spacer region of each species. It was able to identify the seven target species with 93.6% accuracy, which exceeds that of the general biochemical methods. The phylogenetic analyses, using 16S rDNA sequences of the probiotic isolates, also provided further support that the results from the multiplex PCR assay were trustworthy. Taken together, we suggest that the multiplex primer set is an efficient tool for simple, rapid and reliable identification of seven Lactobacillus species.

  20. Nuclear ribosomal internal transcribed spacer 1 (ITS1) variation in the Anastrepha fraterculus cryptic species complex (Diptera, Tephritidae) of the Andean region

    Science.gov (United States)

    Sutton, Bruce D.; Steck, Gary J.; Norrbom, Allen L.; Rodriguez, Erick J.; Srivastava, Pratibha; Alvarado, Norma Nolazco; Colque, Fredy; Landa, Erick Yábar; Sánchez, Juan José Lagrava; Quisberth, Elizabeth; Peñaranda, Emilio Arévalo; Clavijo, P. A. Rodriguez; Alvarez-Baca, Jeniffer K.; Zapata, Tito Guevara; Ponce, Patricio

    2015-01-01

    Abstract The nuclear ribosomal internal transcribed spacer 1 (ITS1) was sequenced for Anastrepha fraterculus (Wiedemann, 1830) originating from 85 collections from the northern and central Andean countries of South America including Argentina (Tucumán), Bolivia, Perú, Ecuador, Colombia, and Venezuela. The ITS1 regions of additional specimens (17 collections) from Central America (México, Guatemala, Costa Rica, and Panamá), Brazil, Caribbean Colombia, and coastal Venezuela were sequenced and together with published sequences (Paraguay) provided context for interpretation. A total of six ITS1 sequence variants were recognized in the Andean region comprising four groups. Type I predominates in the southernmost range of Anastrepha fraterculus. Type II predominates in its northernmost range. In the central and northern Andes, the geographic distributions overlap and interdigitate with a strong elevational effect. A discussion of relationships between observed ITS1 types and morphometric types is included. PMID:26798259

  1. A two-locus global DNA barcode for land plants: the coding rbcL gene complements the non-coding trnH-psbA spacer region.

    Science.gov (United States)

    Kress, W John; Erickson, David L

    2007-06-06

    A useful DNA barcode requires sufficient sequence variation to distinguish between species and ease of application across a broad range of taxa. Discovery of a DNA barcode for land plants has been limited by intrinsically lower rates of sequence evolution in plant genomes than that observed in animals. This low rate has complicated the trade-off in finding a locus that is universal and readily sequenced and has sufficiently high sequence divergence at the species-level. Here, a global plant DNA barcode system is evaluated by comparing universal application and degree of sequence divergence for nine putative barcode loci, including coding and non-coding regions, singly and in pairs across a phylogenetically diverse set of 48 genera (two species per genus). No single locus could discriminate among species in a pair in more than 79% of genera, whereas discrimination increased to nearly 88% when the non-coding trnH-psbA spacer was paired with one of three coding loci, including rbcL. In silico trials were conducted in which DNA sequences from GenBank were used to further evaluate the discriminatory power of a subset of these loci. These trials supported the earlier observation that trnH-psbA coupled with rbcL can correctly identify and discriminate among related species. A combination of the non-coding trnH-psbA spacer region and a portion of the coding rbcL gene is recommended as a two-locus global land plant barcode that provides the necessary universality and species discrimination.

  2. Low-copy nuclear primers and ycf1 primers in Cactaceae.

    Science.gov (United States)

    Franck, Alan R; Cochrane, Bruce J; Garey, James R

    2012-10-01

    To increase the number of variable regions available for phylogenetic study in the Cactaceae, primers were developed for a portion of the plastid ycf1 gene and intron-spanning regions of two low-copy nuclear genes (isi1, nhx1). • Primers were tested on several families within Caryophyllales, focusing on the Cactaceae. Gel electrophoresis indicated positive amplification in most samples. Sequences of these three regions (isi1, nhx1, ycf1) from Harrisia exhibited variation similar to or greater than two plastid regions (atpB-rbcL intergenic spacer and rpl16 intron). • The isi, nhx, and ycf1 primers amplify phylogenetically useful information applicable to the Cactaceae and other families in the Caryophyllales.

  3. Invariance of the magnetic behavior and AMI in ferromagnetic biphase films with distinct non-magnetic metallic spacers

    Energy Technology Data Exchange (ETDEWEB)

    Silva, E.F. [Departamento de Física, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil); Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife, PE (Brazil); Gamino, M. [Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife, PE (Brazil); Instituto de Física, Universidade Federal do Rio Grande de Sul, 91501-970 Porto Alegre, RS (Brazil); Andrade, A.M.H. de [Instituto de Física, Universidade Federal do Rio Grande de Sul, 91501-970 Porto Alegre, RS (Brazil); Vázquez, M. [Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid (Spain); Correa, M.A. [Departamento de Física, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil); Bohn, F., E-mail: felipebohn@fisica.ufrn.br [Departamento de Física, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil)

    2017-02-01

    We investigate the quasi-static magnetic, magnetotransport, and dynamic magnetic properties in ferromagnetic biphase films with distinct non-magnetic metallic spacer layers. We observe that the nature of the non-magnetic metallic spacer material does not have significant influence on the overall biphase magnetic behavior, and, consequently, on the magnetotransport and dynamic magnetic responses. We focus on the magnetoimpedance effect and verify that the films present asymmetric magnetoimpedance effect. Moreover, we explore the possibility of tuning the linear region of the magnetoimpedance curves around zero magnetic field by varying the probe current frequency in order to achieve higher sensitivity values. The invariance of the magnetic behavior and the asymmetric magnetoimpedance effect in ferromagnetic biphase films with distinct non-magnetic metallic spacers place them as promising candidates for probe element and open possibilities to the development of lower-cost high sensitivity linear magnetic field sensor devices.

  4. BWR fuel assembly having fuel rod spacers axially positioned by exterior springs

    International Nuclear Information System (INIS)

    Taleyarkhan, R.P.

    1988-01-01

    In a fuel assembly having spaced fuel rods, an outer hollow tubular flow channel surrounding the fuel rods so as to direct flow of coolant/moderator fluid there-along, and at least one spacer being disposed along the channel and about the fuel rods so as to maintain them in side-by-side spaced relationship, an arrangement for disposing the spacer in a desired axial position along the fuel rods is described comprising: yieldably resilient springs disposed between an interior side of the outer channel and an exterior side of the spacer. The springs have an inherent spring bias directed away from the exterior sides of the spacers and toward the interior side of the channel such that by contact with the channel and spacer the springs assume states in which they are deflected away from the channel interior side so as to exert sufficient compressive contacting force thereon to maintain the spacer substantially stationary in the desired axial position along the fuel rods

  5. Analyses of the Collapse Behavior of a Spacer Grid

    International Nuclear Information System (INIS)

    Jang, Myung-Geun; Na, Geum Ju; Jag, Yeon-Hui; Kim, Hee Cheol; Kim, Jong-Bong; Kim, Jaeyoug

    2016-01-01

    In order to investigate the protection capability of a spacer grid assembly for impact load, a hammer impact test has been carried out. The crush strength is measured in the hammer impact test. Song et al. carried out the experiment and finite element analysis for the hammer impact test for various weld line depth. Park et al. designed the spacer grid shape to get required crush strength via finite element analysis. Song et al. also optimized the spacer grid shape to maximize the crush strength, and carried out the finite element analysis for the hammer impact test considering the weld properties. Kim et al. carried out finite element analysis for various guide tube hole shape and compared the crush shape and crush strength. In this study, the effect of shape defect on the crush behavior in the hammer impact test is investigated. The spacer grid cannot be exactly the square. Therefore a lateral displacement (imperfection) is imposed to square spacer grid and then hammer impact is carried out. The effect of the lateral imperfection on the crush strength is investigated. The effect of the shape defect on the crushing behavior in the hammer impact test is investigated by finite element analysis. It is shown that the collapse become severe as the lateral imperfection displacement increases, especially when the imperfection is greater than or equal to 0.7 mm

  6. Numerical analysis of the spacer grids' compression strength

    Energy Technology Data Exchange (ETDEWEB)

    Schettino, C.F.M.; Gouvea, J.P.; Medeiros, N., E-mail: carlosschettino@inb.gov.br, E-mail: jpg@metal.eeimvr.uff.br [Universidade Federal Fluminense (UFF), Volta Redonda, RJ (Brazil). Programa de Engenharia Metalurgica

    2013-07-01

    Among the components of the fuel assembly, the spacer grids play an important structural role during the energy generation process, mainly for their requirement to have enough structural strength to withstand lateral impact loads, due to fuel assembly shipping/handling and due to forces outcome from postulated accidents (earthquake and LOCA). This requirement ensures a proper geometry for cooling and for guide thimble straightness in the fuel assembly. In this way, the understanding of the macroscopic mechanical behavior of this component becomes essential even to any subsequent geometrical modifications to optimize the flue assemblies' structural behavior. In the present work, three-dimensional finite element models destined to provide consistent predictions of 16X16-type spacer grids lateral strength were proposed. Firstly, buckling tests based on results available in the literature were performed to establish a methodology for spacer grid finite element-based modeling. The, by considering a spacer grid interesting geometry and some possible variations associated to its fabrication, tolerance, the proposed numerical models were submitted to compression conditions to calculate the buckling force. Also, these models were validated for comparison with experimental buckling load results. Comparison of buckling predictions combined to observations of actual and simulated deformed spacer grids geometries permitted to verify the consistency and applicability of the proposed models. Thus, these numerical results show a good agreement between the and the experimental results. (author)

  7. Impact of spacer thickness on biofouling in forward osmosis

    KAUST Repository

    Valladares Linares, Rodrigo

    2014-06-01

    Forward osmosis (FO) indirect desalination systems integrate wastewater recovery with seawater desalination. Niche applications for FO systems have been reported recently, due to the demonstrated advantages compared to conventional high-pressure membrane processes such as nanofiltration (NF) and reverse osmosis (RO). Among them, wastewater recovery has been identified to be particularly suitable for practical applications. However, biofouling in FO membranes has rarely been studied in applications involving wastewater effluents. Feed spacers separating the membrane sheets in cross-flow systems play an important role in biofilm formation. The objective of this study was to determine the influence of feed spacer thickness (28, 31 and 46mil) on biofouling development and membrane performance in a FO system, using identical cross-flow cells in parallel studies. Flux development, biomass accumulation, fouling localization and composition were determined and analyzed. For all spacer thicknesses, operated at the same feed flow and the same run time, the same amount of biomass was found, while the flux reduction decreased with thicker spacers. These observations are in good agreement with biofouling studies for RO systems, considering the key differences between FO and RO. Our findings contradict previous cross-flow studies on particulate/colloidal fouling, where higher cross-flow velocities improved system performance. Thicker spacers reduced the impact of biofouling on FO membrane flux. © 2014 Elsevier Ltd.

  8. Impact of spacer thickness on biofouling in forward osmosis.

    Science.gov (United States)

    Valladares Linares, R; Bucs, Sz S; Li, Z; AbuGhdeeb, M; Amy, G; Vrouwenvelder, J S

    2014-06-15

    Forward osmosis (FO) indirect desalination systems integrate wastewater recovery with seawater desalination. Niche applications for FO systems have been reported recently, due to the demonstrated advantages compared to conventional high-pressure membrane processes such as nanofiltration (NF) and reverse osmosis (RO). Among them, wastewater recovery has been identified to be particularly suitable for practical applications. However, biofouling in FO membranes has rarely been studied in applications involving wastewater effluents. Feed spacers separating the membrane sheets in cross-flow systems play an important role in biofilm formation. The objective of this study was to determine the influence of feed spacer thickness (28, 31 and 46 mil) on biofouling development and membrane performance in a FO system, using identical cross-flow cells in parallel studies. Flux development, biomass accumulation, fouling localization and composition were determined and analyzed. For all spacer thicknesses, operated at the same feed flow and the same run time, the same amount of biomass was found, while the flux reduction decreased with thicker spacers. These observations are in good agreement with biofouling studies for RO systems, considering the key differences between FO and RO. Our findings contradict previous cross-flow studies on particulate/colloidal fouling, where higher cross-flow velocities improved system performance. Thicker spacers reduced the impact of biofouling on FO membrane flux. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Impact of spacer thickness on biofouling in forward osmosis

    KAUST Repository

    Valladares Linares, Rodrigo; Bucs, Szilard; Li, Z.; AbuGhdeeb, M.; Amy, Gary L.; Vrouwenvelder, Johannes S.

    2014-01-01

    Forward osmosis (FO) indirect desalination systems integrate wastewater recovery with seawater desalination. Niche applications for FO systems have been reported recently, due to the demonstrated advantages compared to conventional high-pressure membrane processes such as nanofiltration (NF) and reverse osmosis (RO). Among them, wastewater recovery has been identified to be particularly suitable for practical applications. However, biofouling in FO membranes has rarely been studied in applications involving wastewater effluents. Feed spacers separating the membrane sheets in cross-flow systems play an important role in biofilm formation. The objective of this study was to determine the influence of feed spacer thickness (28, 31 and 46mil) on biofouling development and membrane performance in a FO system, using identical cross-flow cells in parallel studies. Flux development, biomass accumulation, fouling localization and composition were determined and analyzed. For all spacer thicknesses, operated at the same feed flow and the same run time, the same amount of biomass was found, while the flux reduction decreased with thicker spacers. These observations are in good agreement with biofouling studies for RO systems, considering the key differences between FO and RO. Our findings contradict previous cross-flow studies on particulate/colloidal fouling, where higher cross-flow velocities improved system performance. Thicker spacers reduced the impact of biofouling on FO membrane flux. © 2014 Elsevier Ltd.

  10. Development of Primer Sets for Loop-Mediated Isothermal Amplification that Enables Rapid and Specific Detection of Streptococcus dysgalactiae, Streptococcus uberis and Streptococcus agalactiae

    Directory of Open Access Journals (Sweden)

    Deguo Wang

    2015-05-01

    Full Text Available Streptococcus dysgalactiae, Streptococcus uberis and Streptococcus agalactiae are the three main pathogens causing bovine mastitis, with great losses to the dairy industry. Rapid and specific loop-mediated isothermal amplification methods (LAMP for identification and differentiation of these three pathogens are not available. With the 16S rRNA gene and 16S-23S rRNA intergenic spacers as targets, four sets of LAMP primers were designed for identification and differentiation of S. dysgalactiae, S. uberis and S. agalactiae. The detection limit of all four LAMP primer sets were 0.1 pg DNA template per reaction, the LAMP method with 16S rRNA gene and 16S-23S rRNA intergenic spacers as the targets can differentiate the three pathogens, which is potentially useful in epidemiological studies.

  11. Development of Primer Sets for Loop-Mediated Isothermal Amplification that Enables Rapid and Specific Detection of Streptococcus dysgalactiae, Streptococcus uberis and Streptococcus agalactiae.

    Science.gov (United States)

    Wang, Deguo; Liu, Yanhong

    2015-05-26

    Streptococcus dysgalactiae, Streptococcus uberis and Streptococcus agalactiae are the three main pathogens causing bovine mastitis, with great losses to the dairy industry. Rapid and specific loop-mediated isothermal amplification methods (LAMP) for identification and differentiation of these three pathogens are not available. With the 16S rRNA gene and 16S-23S rRNA intergenic spacers as targets, four sets of LAMP primers were designed for identification and differentiation of S. dysgalactiae, S. uberis and S. agalactiae. The detection limit of all four LAMP primer sets were 0.1 pg DNA template per reaction, the LAMP method with 16S rRNA gene and 16S-23S rRNA intergenic spacers as the targets can differentiate the three pathogens, which is potentially useful in epidemiological studies.

  12. Optimized Design of Spacer in Electrodialyzer Using CFD Simulation Method

    Science.gov (United States)

    Jia, Yuxiang; Yan, Chunsheng; Chen, Lijun; Hu, Yangdong

    2018-06-01

    In this study, the effects of length-width ratio and diversion trench of the spacer on the fluid flow behavior in an electrodialyzer have been investigated through CFD simulation method. The relevant information, including the pressure drop, velocity vector distribution and shear stress distribution, demonstrates the importance of optimized design of the spacer in an electrodialysis process. The results show width of the diversion trench has a great effect on the fluid flow compared with length. Increase of the diversion trench width could strength the fluid flow, but also increase the pressure drop. Secondly, the dead zone of the fluid flow decreases with increase of length-width ratio of the spacer, but the pressure drop increases with the increase of length-width ratio of the spacer. So the appropriate length-width ratio of the space should be moderate.

  13. Unique haplotypes of cacao trees as revealed by trnH-psbA chloroplast DNA

    Directory of Open Access Journals (Sweden)

    Nidia Gutiérrez-López

    2016-04-01

    Full Text Available Cacao trees have been cultivated in Mesoamerica for at least 4,000 years. In this study, we analyzed sequence variation in the chloroplast DNA trnH-psbA intergenic spacer from 28 cacao trees from different farms in the Soconusco region in southern Mexico. Genetic relationships were established by two analysis approaches based on geographic origin (five populations and genetic origin (based on a previous study. We identified six polymorphic sites, including five insertion/deletion (indels types and one transversion. The overall nucleotide diversity was low for both approaches (geographic = 0.0032 and genetic = 0.0038. Conversely, we obtained moderate to high haplotype diversity (0.66 and 0.80 with 10 and 12 haplotypes, respectively. The common haplotype (H1 for both networks included cacao trees from all geographic locations (geographic approach and four genetic groups (genetic approach. This common haplotype (ancient derived a set of intermediate haplotypes and singletons interconnected by one or two mutational steps, which suggested directional selection and event purification from the expansion of narrow populations. Cacao trees from Soconusco region were grouped into one cluster without any evidence of subclustering based on AMOVA (FST = 0 and SAMOVA (FST = 0.04393 results. One population (Mazatán showed a high haplotype frequency; thus, this population could be considered an important reservoir of genetic material. The indels located in the trnH-psbA intergenic spacer of cacao trees could be useful as markers for the development of DNA barcoding.

  14. A Study on Cell Size of Irradiated Spacer Grid for PWR Fuel

    International Nuclear Information System (INIS)

    Jin, Y. G.; Kim, G. S.; Ryu, W. S. and others

    2014-01-01

    The spacer grids supporting the fuel rods absorb vibration impacts due to the reactor coolant flow, and grid spring force decreases under irradiation. This reduction of contact force might cause grid-to-rod fretting wear. The fretting failure of the fuel rod is one of the recent significant issues in the nuclear industry from an economical as well as a safety concern. Thus, it is important to understand the characteristics of cell spring behavior and the change in size of grid cells for an irradiated spacer grid. In the present study, the dimensional measurement of a spacer grid was conducted to investigate the cell size of an irradiated spacer grid in a hot cell at IMEF (Irradiated Materials Examination Facility) of KAERI. To evaluate the fretting wear performance of an irradiated spacer grid, hot cell tests were carried out at IMEF of KAERI. Hot cell examinations include dimensional measurements for the irradiated spacer grid. The change of cell sizes was dependent on the direction of the spacer grids, leading to significant gap variations. It was found that the change in size of the cell springs due to irradiation-induced stress relaxation and creep during the fuel residency in the reactor core affect the contact behavior between the fuel rod and the cell spring

  15. Heterogeneous diversity of spacers within CRISPR

    Science.gov (United States)

    Deem, Michael; He, Jiankui

    2011-03-01

    Clustered regularly interspaced short palindromic repeats (CRISPR) in bacterial and archaeal DNA have recently been shown to be a new type of anti-viral immune system in these organisms. We here study the diversity of spacers in CRISPR under selective pressure. We propose a population dynamics model that explains the biological observation that the leader-proximal end of CRISPR is more diversified and the leader-distal end of CRISPR is more conserved. This result is shown to be in agreement with recent experiments. Our results show that the CRISPR spacer structure is influenced by and provides a record of the viral challenges that bacteria face. 1) J. He and M. W. Deem, Phys. Rev. Lett. 105 (2010) 128102

  16. ATLAS barrel hadron tile calorimeter: spacers plates mass production

    International Nuclear Information System (INIS)

    Artikov, A.M.; Budagov, Yu.A.; Khubua, J.

    1999-01-01

    In this article we expose the main problems of the mass production of the so-called 'spacer plates' for the ATLAS Barrel Hadron Tile Calorimeter. We describe all practical solutions of these problems. Particularly we present the measurement procedures and calculation schemes we used for the spacers dimensions determination. The results of the calculations are presented

  17. On the impact analysis of a PWR spacer grid

    International Nuclear Information System (INIS)

    Song, Kee Nam; Lee, S. H.

    2012-01-01

    A spacer grid, which is an interconnected array of slotted grid straps and is welded at the intersections to form an egg crate structure, is one of the most important structural components in a PWR fuel assembly. From a structural point of view, the spacer grid is required to have sufficient crush strength under lateral loads so that nuclear fuel rods are maintained in a cool able geometry, and that control rods can be inserted. The capacity of a spacer grid to resist lateral loads is usually characterized in terms of its crush strength, and it was reported that the lateral crush strength of the spacer grid is closely related with welding quality of the spacer grid. Microstructures in the weld zone, including a heat affected zone (HAZ), are different from that in a parent material. Consequently, the mechanical properties in the weld zone are different from those in the parent material to some extent. When a welded structure is loaded, the mechanical behavior of the welded structure might be different from the case of a structure with homogeneous mechanical properties. Nonetheless, mechanical properties in the welded structure have been neglected in many structural analyses of the spacer grid due to a lack of mechanical properties in the weld zone. When the weld zone is very narrow and the interfaces are not clear, it is difficult to take tensile test specimens in the weld zone. The reason for this is that the mechanical properties in the parent material are usually used in the structural analyses in the welded structure. As an aside, it has been recently determined that the ball indentation technique has the potential to be an excellent substitute for a standard tensile test, particularly in the case of small specimens or property gradient materials such as welds. In this study, to investigate the effect on the mechanical behavior of the spacer grid when using weld mechanical properties, strength analyses considering the weld mechanical properties recently obtained

  18. Impact of feed spacer and membrane modification by hydrophilic, bactericidal and biocidal coating on biofouling control

    KAUST Repository

    Araújo, Paula A.

    2012-06-01

    The influence of polydopamine- and polydopamine-. graft-poly(ethylene glycol)-coated feed spacers and membranes, copper-coated feed spacers, and commercially-available biostatic feed spacers on biofouling has been studied in membrane fouling simulators. Feed spacers and membranes applied in practical membrane filtration systems were used; biofouling development was monitored by feed channel pressure drop increase and biomass accumulation. Polydopamine and polydopamine-. g-PEG are hydrophilic surface modification agents expected to resist protein and bacterial adhesion, while copper feed spacer coatings and biocides infused in feed spacers are expected to restrict biological growth. Our studies showed that polydopamine and polydopamine-. g-PEG coatings on feed spacers and membranes, copper coatings on feed spacers, and a commercial biostatic feed spacer did not have a significant impact on feed channel pressure drop increase and biofilm accumulation as measured by ATP and TOC content. The studied spacer and membrane modifications were not effective for biofouling control; it is doubtful that feed spacer and membrane modification, in general, may be effective for biofouling control regardless of the type of applied coating. © 2012 Elsevier B.V.

  19. Effects of grid spacer with mixing vane on entrainments and depositions in two-phase annular flows

    Directory of Open Access Journals (Sweden)

    Akimaro Kawahara

    2015-06-01

    Full Text Available The effects of mixing vanes (MVs attached to a grid spacer on the characteristics of air–water annular flows were experimentally investigated. To know the effects, a grid spacer with or without MV was inserted in a vertical circular pipe of 16-mm internal diameter. For three cases (i.e., no spacer, spacer without MV, and spacer with MV, the liquid film thickness, liquid entrainment fraction, and deposition rate were measured by the constant current method, single liquid film extraction method, and double liquid film extraction method, respectively. The MVs significantly promote the re-deposition of liquid droplets in the gas core flow into the liquid film on the channel walls. The deposition mass transfer coefficient is three times higher for the spacer with MV than for the spacer without MV, even for cases 0.3-m downstream from the spacer. The liquid film thickness becomes thicker upstream and downstream for the spacer with MV, compared with the thickness for the spacer without MV and for the case with no spacer.

  20. Extreme conservation of the psaA/psaB intercistronic spacer reveals a translational motif coincident with the evolution of land plants.

    Science.gov (United States)

    Peredo, Elena L; Les, Donald H; King, Ursula M; Benoit, Lori K

    2012-12-01

    Although chloroplast transcriptional and translational mechanisms were derived originally from prokaryote endosymbionts, chloroplasts retain comparatively few genes as a consequence of the overall transfer to the nucleus of functions associated formerly with prokaryotic genomes. Various modifications reflect other evolutionary shifts toward eukaryotic regulation such as posttranscriptional transcript cleavage with individually processed cistrons in operons and gene expression regulated by nuclear-encoded sigma factors. We report a notable exception for the psaA-psaB-rps14 operon of land plant (embryophyte) chloroplasts, where the first two cistrons are separated by a spacer region to which no significant role had been attributed. We infer an important function of this region, as indicated by the conservation of identical, structurally significant sequences across embryophytes and their ancestral protist lineages, which diverged some 0.5 billion years ago. The psaA/psaB spacers of embryophytes and their progenitors exhibit few sequence and length variants, with most modeled transcripts resolving the same secondary structure: a loop with projecting Shine-Dalgarno site and well-defined stem that interacts with adjacent coding regions to sequester the psaB start codon. Although many functions of the original endosymbiont have been usurped by nuclear genes or interactions, conserved functional elements of embryophyte psaA/psaB spacers provide compelling evidence that translation of psaB is regulated here by a cis-acting mechanism comparable to those common in prokaryotes. Modeled transcripts also indicate that spacer variants in some plants (e.g., aquatic genus Najas) potentially reflect ecological adaptations to facilitate temperature-regulated translation of psaB.

  1. Phylogenetic relationships in Taxodiaceae and Cupressaceae sensu stricto based on matK gene, chlL gene, trnL-trnF IGS region, and trnL intron sequences.

    Science.gov (United States)

    Kusumi, J; Tsumura, Y; Yoshimaru, H; Tachida, H

    2000-10-01

    Nucleotide sequences from four chloroplast genes, the matK, chlL, intergenic spacer (IGS) region between trnL and trnF, and an intron of trnL, were determined from all species of Taxodiaceae and five species of Cupressaceae sensu stricto (s.s.). Phylogenetic trees were constructed using the maximum parsimony and the neighbor-joining methods with Cunninghamia as an outgroup. These analyses provided greater resolution of relationships among genera and higher bootstrap supports for clades compared to previous analyses. Results indicate that Taiwania diverged first, and then Athrotaxis diverged from the remaining genera. Metasequoia, Sequoia, and Sequoiadendron form a clade. Taxodium and Glyptostrobus form a clade, which is the sister to Cryptomeria. Cupressaceae s.s. are derived from within Taxodiaceae, being the most closely related to the Cryptomeria/Taxodium/Glyptostrobus clade. These relationships are consistent with previous morphological groupings and the analyses of molecular data. In addition, we found acceleration of evolutionary rates in Cupressaceae s.s. Possible causes for the acceleration are discussed.

  2. Primers for phylogeny reconstruction in Bignonieae (Bignoniaceae) using herbarium samples.

    Science.gov (United States)

    Zuntini, Alexandre R; Fonseca, Luiz Henrique M; Lohmann, Lúcia G

    2013-09-01

    New primers were developed for Bignonieae to enable phylogenetic studies within this clade using herbarium samples. • Internal primers were designed based on available sequences of the plastid ndhF gene and the rpl32-trnL intergenic spacer region, and the nuclear gene PepC. The resulting primers were used to amplify DNA extracted from herbarium materials. High-quality data were obtained from herbarium samples up to 53 yr old. • The standardized methodology allows the inclusion of herbarium materials as alternative sources of DNA for phylogenetic studies in Bignonieae.

  3. Transcriptional regulator-mediated activation of adaptation genes triggers CRISPR de novo spacer acquisition

    DEFF Research Database (Denmark)

    Liu, Tao; Li, Yingjun; Wang, Xiaodi

    2015-01-01

    Acquisition of de novo spacer sequences confers CRISPR-Cas with a memory to defend against invading genetic elements. However, the mechanism of regulation of CRISPR spacer acquisition remains unknown. Here we examine the transcriptional regulation of the conserved spacer acquisition genes in Type I......, it was demonstrated that the transcription level of csa1, cas1, cas2 and cas4 was significantly enhanced in a csa3a-overexpression strain and, moreover, the Csa1 and Cas1 protein levels were increased in this strain. Furthermore, we demonstrated the hyperactive uptake of unique spacers within both CRISPR loci...... in the presence of the csa3a overexpression vector. The spacer acquisition process is dependent on the CCN PAM sequence and protospacer selection is random and non-directional. These results suggested a regulation mechanism of CRISPR spacer acquisition where a single transcriptional regulator senses the presence...

  4. Polyetheretherketone (PEEK) Spacers for Anterior Cervical Fusion: A Retrospective Comparative Effectiveness Clinical Trial.

    Science.gov (United States)

    Lemcke, Johannes; Al-Zain, Ferass; Meier, Ullrich; Suess, Olaf

    2011-01-01

    Anterior cervical decompression and fusion (ACDF) is the standard surgical treatment for radiculopathy and myelopathy. Polyetheretherketone (PEEK) has an elasticity similar to bone and thus appears well suited for use as the implant in ACDF procedures. The aim of this study is to examine the clinical and radiographic outcome of patients treated with standing alone PEEK spacers without bone morphogenic protein (BMP) or plating and to examine the influence of the different design of the two spacers on the rate of subsidence and dislocation. This retrospective comparative study reviewed 335 patients treated by ACDF in a specialized urban hospital for radiculopathy or myelopathy due to degenerative pathologies. The Intromed PEEK spacer was used in 181 patients from 3/2002 to 11/2004, and the AMT SHELL spacer was implanted in 154 patients from 4/2004 to 12/2007. The follow-up rate was 100% at three months post-op and 82.7% (277 patients) at one year. The patients were assessed with the Japanese Orthopedic Association (JOA) questionnaire and radiographically. At the one-year follow-up there were 118/277 patients with an excellent clinical outcome on the JOA, 112/277 with a good outcome, 20/277 with a fair outcome, and 27/277 with a poor outcome. Subsidence was observed in 13.3% of patients with the Intromed spacer vs 8.4% of the patients with the AMT SHELL. Dislocation of the spacer was observed in 10 of the 181 patients with Intromed spacers but in none of the 154 patients with Shell spacers. The study demonstrates that ACDF with standing alone PEEK cages leads to excellent and good clinical outcomes. The differences we observed in the subsidence rate between the two spacers were not significant and cannot be related to a single design feature of the spacers.

  5. Measurement and CFD calculation of spacer loss coefficient for a tight-lattice fuel bundle

    International Nuclear Information System (INIS)

    In, Wang Kee; Shin, Chang Hwan; Kwack, Young Kyun; Lee, Chi Young

    2015-01-01

    Highlights: • Experiment and CFD analysis evaluated the pressure drop in a spacer grid. • The measurement and CFD errors for the spacer loss coefficient were estimated. • The spacer loss coefficient for the dual-cooled annular fuel bundle was determined. • The CFD prediction agrees with the measured spacer loss coefficient within 8%. - Abstract: An experiment and computational fluid dynamics (CFD) analysis were performed to evaluate the pressure drop in a spacer grid for a dual-cooled annular fuel (DCAF) bundle. The DCAF bundle for the Korean optimum power reactor (OPR1000) is a 12 × 12 tight-lattice rod array with a pitch-to-diameter ratio of 1.08 owing to a larger outer diameter of the annular fuel rod. An experiment was conducted to measure the pressure drop in spacer grid for the DCAF bundle. The test bundle is a full-size 12 × 12 rod bundle with 11 spacer grid. The test condition covers a Reynolds number range of 2 × 10 4 –2 × 10 5 by changing the temperature and flow rate of water. A CFD analysis was also performed to predict the pressure drop through a spacer grid using the full-size and partial bundle models. The pressure drop and loss coefficient of a spacer grid were predicted and compared with the experimental results. The CFD predictions of spacer pressure drop and loss coefficient agree with the measured values within 8%. The spacer loss coefficient for the DCAF bundle is estimated to be approximately 1.50 at a nominal operating condition of OPR1000, i.e., Re = 4 × 10 5

  6. Success of Two-Stage Reimplantation in Patients Requiring an Interim Spacer Exchange.

    Science.gov (United States)

    George, Jaiben; Miller, Evan M; Curtis, Gannon L; Klika, Alison K; Barsoum, Wael K; Mont, Michael A; Higuera, Carlos A

    2018-03-23

    Some patients undergoing a 2-stage revision for a periprosthetic joint infection require a repeat spacer in the interim (removal of existing spacer with insertion of a new spacer or spacer exchange) due to persistent infection. The objectives of this study are to (1) determine the factors associated with patients who receive a repeat spacer and (2) compare the infection-free survival (overall and stratified by joint type) of reimplantation in patients who did or did not receive a repeat spacer. From 2001 to 2014, 347 hip or knee 2-stage revisions that finally underwent reimplantation and had a minimum 2-year follow-up were identified. An interim spacer exchange was performed in 59 (17%) patients (exchange cohort). Patient-related and organism-related factors were compared between the exchange and non-exchange cohorts. Kaplan-Meier survival curves were performed to assess the success (absence of signs of infection, reoperation for infection, periprosthetic joint infection-related mortality) of both cohorts. Patients in the exchange group had higher comorbidity score (P = .020), prolonged time to reimplantation (P exchange cohort, and 78% (knee 77%, hip 78%) in the non-exchange cohort (P = .020). Patients requiring an interim spacer exchange were found to have more comorbidities, prolonged treatment period, and were more likely to be infected with a resistant organism. About one-third of such patients became reinfected within 5 years compared to only one-fifth of the patients without an interim spacer exchange. Copyright © 2018 Elsevier Inc. All rights reserved.

  7. Separator-spacer for electrochemical systems

    Science.gov (United States)

    Grimes, Patrick G.; Einstein, Harry; Newby, Kenneth R.; Bellows, Richard J.

    1983-08-02

    An electrochemical cell construction features a novel co-extruded plastic electrode in an interleaved construction with a novel integral separator-spacer. Also featured is a leak and impact resistant construction for preventing the spill of corrosive materials in the event of rupture.

  8. Effects of different rod spacers (helical types) on coolant crossmixing

    International Nuclear Information System (INIS)

    Zhukov, A.V.; Sviridenko, E.Ya.; Matyukhin, N.M.; Rymkevich, K.S.; Ushakov, P.A.

    1981-11-01

    The results of investigations (electromagnetic measuring method) on coolant cross mixing in rod clusters with spiral wire spacers with different winding directions, with alternating unfinned and finned rods (case 'fin to rod'), as well as in rod clusters with much space between the rods, (case 'fin to fin') are reported. The local fluid dynamics parameters (distribution of the transversal and longitudinal velocity component) that define the physical processes of the coolant exchange in the rod clusters with helical spacers are explained. The investigation results for different helical spacer types are compared with each other. (orig.) [de

  9. Characterization and intraspecific variation of Fusarium semitectum ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-01-18

    Jan 18, 2010 ... and ground to a fine powder in a sterile mortar with liquid nitrogen. .... Figure 1. Microscopic characteristics showed by F. semitectum associated with H. ...... Meiotic segregation and recombination of the intergenic spacer of the.

  10. Experimental study of mechanical properties on spacer in NHR

    International Nuclear Information System (INIS)

    Jiang Yueyuan; Shi Jibing; Xu Yong

    2007-01-01

    The spacer of NHR-200 is composed mainly of the inner, outer and cornual strips which are ranged in egg-crate of 12 x 12-3. First, the pre-distortion of three kinds of three-arc springs on reactor working condition and their related clipping-force ranges are analyzed in this paper. Secondly, the mechanical experiments of 1:1 prototype, such as the load-distortion experiments, which the load and distortion are respectively measured by strain gauge and displacement sensor, of three kinds of springs, rigid supports and the spacers in two different directions are carried out on a special experimental facility. The experimental results show that the spacer can completely meet the design demands of mechanical properties of the fuel assemblies in NHR-200. (authors)

  11. Solution-processed organic tandem solar cells with embedded optical spacers

    NARCIS (Netherlands)

    Hadipour, Afshin; de Boer, Bert; Blom, Paul W. M.

    2007-01-01

    We demonstrate a solution-processed polymer tandem solar cell in which the two photoactive single cells are separated by an optical spacer. The use of an optical spacer allows for an independent optimization of both the electronic and optical properties of the tandem cell. The optical transmission

  12. Local repeat sequence organization of an intergenic spacer in the ...

    Indian Academy of Sciences (India)

    Unknown

    chloroplast genome of Chlamydomonas reinhardtii leads to DNA expansion and sequence ... The discovery of uniparentally inherited streptomycin resistant mutants ... resembles yeast, mitochondrial and phage recombination in that it is typically ...... Sager R and Lane D 1972 Molecular basis of maternal inheritance; Proc.

  13. 3-D flow analyses for design of nuclear fuel spacer

    Energy Technology Data Exchange (ETDEWEB)

    Karouta, Z. [ABB Combustion Engineering, Windsor, CT (United States); GU, Chun-Yuan [ABB Corporate Research, Vaesteras (Sweden); Schoelin, B. [ABB Atom AB, Vaesteras (Sweden)

    1995-09-01

    The Computational Fluid Dynamics (CFD) code, CFDS-FLOW3D, was used to develop improved fuel designs for PWR cores. It was used primarily to understand the fluid dynamics of grid spacers, the mass transfer between subchannels caused by spacers and in the long term to develop two-phase models which enable prediction of critical heat flux in PWR fuel. A single subchannel of one grid span was modeled. In this model different spacer designs with mixing devices were analyzed. A special treatment of the boundary condition was developed making use of flow symmetry to model the mass transfer between different subchannels and minimize the size of the computational model. This reduced the computational model to a fraction of a subchannel using traditional periodic boundary conditions. The Navier-Stokes equation was solved for the liquid and the flow turbulence was modeled by k-{xi} turbulence model. The spacer and mixing device were treated as infinite thin surfaces in the model and a zero velocity condition and turbulent wall function were applied on each side of the thin surfaces. This approach simulated the swirl from the mixing devices well, but had the drawback of not predicting pressure drop accurately since the wake behind the plates and the acceleration effect of the spacers were ignored. CFDS-FLOW3D models with mixing devices were applied in the single-phase flow regime. Velocity profiles from the CFDS-FLOW3D models were compared to Laser Doppler Velocimeter measurements taken from the flow field downstream of spaces in a full scale, cold water test loop. The predicted axial and lateral velocity profiles were in good agreement with the measurements. The evaluation of the performance of different spacer devices was made by comparing the swirl ratio downstream of the grid spacers. It is planned to evaluate heat transfer coefficient downstream of the spaces, to implement two-phase flow models, and to model the superheated boundary layer on the surface of the fuel rod.

  14. Molecular Strain Typing of Clinical Isolates, Trichophyton rubrum using Non Transcribed Spacer (NTS) Region as a Molecular Marker.

    Science.gov (United States)

    Ramaraj, Vijayakumar; Vijayaraman, Rajyoganandh S; Elavarashi, Elangovan; Rangarajan, Sudha; Kindo, Anupma Jyoti

    2017-05-01

    Dermatophytes are a group of fungi which infect keratinized tissues and causes superficial mycoses in humans and animals. The group comprises of three major genera, Trichophyton , Microsporum and Epidermophyton . Among them Trichophyton rubrum is a predominant anthropophilic fungi which causes chronic infections. Although, the infection is superficial and treatable, reinfection/coinfection causes inflation in the treatment cost. Identifying the source and mode of transmission is essential to prevent its transmission. Accurate discrimination is required to understand the clinical (relapse or reinfection) and epidemiological implications of the genetic heterogeneity of this species. Polymorphism in the Non Transcribed Spacer (NTS) region of ribosomal DNA (rDNA) clusters renders an effective way to discriminate strains among T. rubrum . To carry out the strain typing of the clinical isolates, Trichophyton rubrum using NTS as a molecular marker. Seventy T.rubrum clinical isolates obtained from April-2011-March 2013, from Sri Ramachandra Medical Centre, Chennai, Tamil Nadu, India, were identified by conventional phenotypic methods and included in this prospective study. The isolates were then subjected to Polymerase Chain Reaction (PCR) targeting two subrepeat elements (SREs), TRS-1 and TRS-2 of the NTS region. Strain-specific polymorphism was observed in both subrepeat loci. Total, nine different strains were obtained on combining both TRS-1 and TRS-2, SREs. The outcome has given a strong representation for using NTS region amplification in discriminating the T. rubrum clinical isolates. The method can be adapted as a tool for conducting epidemiology and population based study in T. rubrum infections. This will help in future exploration of the epidemiology of T. rubrum .

  15. Sequence analysis of the internal transcribed spacer (ITS) region reveals a novel clade of Ichthyophonus sp. from rainbow trout.

    Science.gov (United States)

    Rasmussen, C; Purcell, M K; Gregg, J L; LaPatra, S E; Winton, J R; Hershberger, P K

    2010-03-09

    The mesomycetozoean parasite Ichthyophonus hoferi is most commonly associated with marine fish hosts but also occurs in some components of the freshwater rainbow trout Oncorhynchus mykiss aquaculture industry in Idaho, USA. It is not certain how the parasite was introduced into rainbow trout culture, but it might have been associated with the historical practice of feeding raw, ground common carp Cyprinus carpio that were caught by commercial fisherman. Here, we report a major genetic division between west coast freshwater and marine isolates of Ichthyophonus hoferi. Sequence differences were not detected in 2 regions of the highly conserved small subunit (18S) rDNA gene; however, nucleotide variation was seen in internal transcribed spacer loci (ITS1 and ITS2), both within and among the isolates. Intra-isolate variation ranged from 2.4 to 7.6 nucleotides over a region consisting of approximately 740 bp. Majority consensus sequences from marine/anadromous hosts differed in only 0 to 3 nucleotides (99.6 to 100% nucleotide identity), while those derived from freshwater rainbow trout had no nucleotide substitutions relative to each other. However, the consensus sequences between isolates from freshwater rainbow trout and those from marine/anadromous hosts differed in 13 to 16 nucleotides (97.8 to 98.2% nucleotide identity).

  16. Spacer geometry and particle deposition in spiral wound membrane feed channels

    KAUST Repository

    Radu, A.I.

    2014-11-01

    Deposition of microspheres mimicking bacterial cells was studied experimentally and with a numerical model in feed spacer membrane channels, as used in spiral wound nanofiltration (NF) and reverse osmosis (RO) membrane systems. In-situ microscopic observations in membrane fouling simulators revealed formation of specific particle deposition patterns for different diamond and ladder feed spacer orientations. A three-dimensional numerical model combining fluid flow with a Lagrangian approach for particle trajectory calculations could describe very well the in-situ observations on particle deposition in flow cells. Feed spacer geometry, positioning and cross-flow velocity sensitively influenced the particle transport and deposition patterns. The deposition patterns were not influenced by permeate production. This combined experimental-modeling approach could be used for feed spacer geometry optimization studies for reduced (bio)fouling. © 2014 Elsevier Ltd.

  17. Application of SRAP in the genetic diversity of Tricholoma matsutake ...

    African Journals Online (AJOL)

    GREGORY

    2010-09-20

    Sep 20, 2010 ... intergenic spacer; PCR, polymerase chain reaction; FST, mean level of ... been developed for any of the matsutake mushrooms, ... SRAP was similar to RAPD, but it was a prefe- ..... belonging to the taxa Pleurotus eryngii (DC.

  18. Genotypic and phenotypic diversity of Bacillus spp. isolated from steel plant waste

    Directory of Open Access Journals (Sweden)

    Chartone-Souza Edmar

    2008-10-01

    Full Text Available Abstract Background Molecular studies of Bacillus diversity in various environments have been reported. However, there have been few investigations concerning Bacillus in steel plant environments. In this study, genotypic and phenotypic diversity and phylogenetic relationships among 40 bacterial isolates recovered from steel plant waste were investigated using classical and molecular methods. Results 16S rDNA partial sequencing assigned all the isolates to the Bacillus genus, with close genetic relatedness to the Bacillus subtilis and Bacillus cereus groups, and to the species Bacillus sphaericus. tDNA-intergenic spacer length polymorphisms and the 16S–23S intergenic transcribed spacer region failed to identify the isolates at the species level. Genomic diversity was investigated by molecular typing with rep (repetitive sequence based PCR using the primer sets ERIC2 (enterobacterial repetitive intergenic consensus, (GTG5, and BOXAIR. Genotypic fingerprinting of the isolates reflected high intraspecies and interspecies diversity. Clustering of the isolates using ERIC-PCR fingerprinting was similar to that obtained from the 16S rRNA gene phylogenetic tree, indicating the potential of the former technique as a simple and useful tool for examining relationships among unknown Bacillus spp. Physiological, biochemical and heavy metal susceptibility profiles also indicated considerable phenotypic diversity. Among the heavy metal compounds tested Zn, Pb and Cu were least toxic to the bacterial isolates, whereas Ag inhibited all isolates at 0.001 mM. Conclusion Isolates with identical 16S rRNA gene sequences had different genomic fingerprints and differed considerably in their physiological capabilities, so the high levels of phenotypic diversity found in this study are likely to have ecological relevance.

  19. Air-water flooding in multirod channels: effects of spacer grids and blockages

    International Nuclear Information System (INIS)

    Cha, Jong Hee; Jun, Hyung Gil

    1993-01-01

    This paper presents the experimental results on flooding of countercurrent flow in vertical multirod channels, which consists of falling water film and upward air flow. In particular, the effects of spacer grids, with and without mixing vane, and of blockage in the multirod bundle on the behaviour of flooding were investigated. The 5 x 5 zircaloy tube bundle was used for the test section. The comparison of previous analytical models and empirical correlations with present data on flooding showed that the existing models and correlations predict much higher flooding curves. The spacer grid causes the lower flooding air flow rate to compare with the bare rod bundle. However, the mixing spacer grids need a higher flooding air flow rate for a constant liquid flow rate than the spacer grids without mixing vanes. The bundle containing blockages has the highest flooding air flow rate among the bundles with spacer grids and blokages. Empirical flooding correlations for the three types of test section have been made. (Author)

  20. Two-stage revision of septic knee prosthesis with articulating knee spacers yields better infection eradication rate than one-stage or two-stage revision with static spacers.

    Science.gov (United States)

    Romanò, C L; Gala, L; Logoluso, N; Romanò, D; Drago, L

    2012-12-01

    The best method for treating chronic periprosthetic knee infection remains controversial. Randomized, comparative studies on treatment modalities are lacking. This systematic review of the literature compares the infection eradication rate after two-stage versus one-stage revision and static versus articulating spacers in two-stage procedures. We reviewed full-text papers and those with an abstract in English published from 1966 through 2011 that reported the success rate of infection eradication after one-stage or two-stage revision with two different types of spacers. In all, 6 original articles reporting the results after one-stage knee exchange arthoplasty (n = 204) and 38 papers reporting on two-stage revision (n = 1,421) were reviewed. The average success rate in the eradication of infection was 89.8% after a two-stage revision and 81.9% after a one-stage procedure at a mean follow-up of 44.7 and 40.7 months, respectively. The average infection eradication rate after a two-stage procedure was slightly, although significantly, higher when an articulating spacer rather than a static spacer was used (91.2 versus 87%). The methodological limitations of this study and the heterogeneous material in the studies reviewed notwithstanding, this systematic review shows that, on average, a two-stage procedure is associated with a higher rate of eradication of infection than one-stage revision for septic knee prosthesis and that articulating spacers are associated with a lower recurrence of infection than static spacers at a comparable mean duration of follow-up. IV.

  1. Boiling transition phenomenon in BWR fuel assemblies effect of fuel spacer shape on critical power

    International Nuclear Information System (INIS)

    Yamamoto, Yasushi; Morooka, Shin-ichi; Mitsutake, Toru; Yokobori, Seiichi; Kimura, Jiro.

    1996-01-01

    A thorough understanding of the thermal-hydraulic phenomena near fuel spacer is necessary for the accurate prediction of the critical power of BWR fuel assemblies, and is thus essential for effective developments of a new BWR fuel assembly. The main purpose of this study is to develop an accurate method for predicting the effect of spacer shapes on critical power. Tests have been conducted under actual BWR operating conditions, using an annulus flow channel consisting of a heated rod and circular-tube channel, and BWR simulated 4x4 rod bundles with heater rods unheated just upsteam of spacer. The effect of spacer shapes on critical power was predicted analytically based on the droplet deposition rate estimation. The droplet deposition rate for different spacer shapes was calculated using a single-phase flow model. The prediction results were compared with the test results for the annulus flow channel using ring-type spacers. Analytical results of critical power agreed with measured critical power from point of the effects of changes in the rod-spacer clearance and the spacer thickness on critical power. (author)

  2. A technical report on the evaluation of the integrity for the TIG welded spacer grid

    International Nuclear Information System (INIS)

    Song, Kee Nam; Yoo, Ho Sik; Lww, Chang Woo

    1994-07-01

    The spacer grid, which supports fuel rods, guide thimble and instrumentation tube, is classified into two types according to their strap material,.ie. inconel and zircaloy spacer grid. KOFA fuel of 14 x 14 and 17 x 17 type has seven and eight spacer grid respectively. Zircaloy spacer grid is assembled by straps whose cross points are welded by TIG welding method. This technical report provides to give some information about structure and function of the spacer grid and the basis and characteristic of the TIG welding method. A series of test which is conducted to evaluate the integrity of TIG welded zircaloy spacer grid and their results have been also studied. (Author) 18 refs., 23 figs., 3 tabs

  3. A technical report on the evaluation of the integrity for the TIG welded spacer grid

    Energy Technology Data Exchange (ETDEWEB)

    Song, Kee Nam; Yoo, Ho Sik; Lww, Chang Woo [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1994-07-01

    The spacer grid, which supports fuel rods, guide thimble and instrumentation tube, is classified into two types according to their strap material,.ie. inconel and zircaloy spacer grid. KOFA fuel of 14 x 14 and 17 x 17 type has seven and eight spacer grid respectively. Zircaloy spacer grid is assembled by straps whose cross points are welded by TIG welding method. This technical report provides to give some information about structure and function of the spacer grid and the basis and characteristic of the TIG welding method. A series of test which is conducted to evaluate the integrity of TIG welded zircaloy spacer grid and their results have been also studied. (Author) 18 refs., 23 figs., 3 tabs.

  4. Numerical simulation of bubble motion about a grid spacer in a rod bundle

    International Nuclear Information System (INIS)

    Zhang, Zheng; Hosokawa, Shigeo; Hayashi, Kosuke; Tomiyama, Akio

    2009-01-01

    Numerical simulations based on a three-dimensional two-way bubble tracking method are carried out to predict bubble motions in a square duct with an obstacle and in a two-by-three rod bundle with a grid spacer. Comparisons between measured and predicted bubble motions demonstrate that the two-way bubble tracking method gives good predictions for trajectories of small bubbles in the upstream side of the grid spacer in the rod bundle geometry. The predicted bubble trajectories clearly show that bubbles are apt to migrate toward the rod surface in the vicinity of the bottom of the grid spacer. Analysis of forces acting on the bubbles confirms that pressure gradient force induced by the presence of the spacer is the main cause of the bubble lateral migration toward the rod surface. Motions of steam bubbles at a nominal operating condition of a pressurized water reactor (PWR) are also predicted by using the bubble tracking method, which indicates that steam bubbles also migrate toward the rod surface at the upstream side of the spacer due to the spacer-induced pressure gradient force. (author)

  5. Modeling the effect of spacers and biofouling on forward osmosis performance

    KAUST Repository

    Mosqueira Santillá n, Marí a José

    2014-01-01

    and operational conditions. For this, a two dimensional numerical model for FO systems was developed using computational fluid dynamics (CFD). This model allowed the evaluation of the impact of (i) spacers and (ii) biofilm, and (iii) the combined impact of spacers

  6. Articulating spacers used in two-stage revision of infected hip and knee prostheses abrade with time.

    Science.gov (United States)

    Fink, Bernd; Rechtenbach, Annett; Büchner, Hubert; Vogt, Sebastian; Hahn, Michael

    2011-04-01

    Articulating spacers used in two-stage revision surgery of infected prostheses have the potential to abrade and subsequently induce third-body wear of the new prosthesis. We asked whether particulate material abraded from spacers could be detected in the synovial membrane 6 weeks after implantation when the spacers were removed for the second stage of the revision. Sixteen hip spacers (cemented prosthesis stem articulating with a cement cup) and four knee spacers (customized mobile cement spacers) were explanted 6 weeks after implantation and the synovial membranes were removed at the same time. The membranes were examined by xray fluorescence spectroscopy, xray diffraction for the presence of abraded particles originating from the spacer material, and analyzed in a semiquantitative manner by inductively coupled plasma mass spectrometry. Histologic analyses also were performed. We found zirconium dioxide in substantial amounts in all samples, and in the specimens of the hip synovial lining, we detected particles that originated from the metal heads of the spacers. Histologically, zirconium oxide particles were seen in the synovial membrane of every spacer and bone cement particles in one knee and two hip spacers. The observations suggest cement spacers do abrade within 6 weeks. Given the presence of abrasion debris, we recommend total synovectomy and extensive lavage during the second-stage reimplantation surgery to minimize the number of abraded particles and any retained bacteria.

  7. Deformation behavior of cell spring of an irradiated spacer grid

    International Nuclear Information System (INIS)

    Jin, Y. G.; Baek, S. J.; Ryu, W. S.; Kim, G. S.; Yoo, B. O.; Kim, D. S.; Ahn, S. B.; Chun, Y. B.; Choo, Y. S.

    2012-01-01

    Mechanical properties of a space grid of a fuel assembly are of great importance for fuel operation reliability in extended fuel burnup and duration of fuel life. The spacer grid with inner and outer straps has cell spring and dimples, which are in contact with the fuel rod. The spacer grids supporting the fuel rods absorb vibration impacts due to the reactor coolant flow and also grid spring force is decreasing under irradiation. This reduction of contact force might cause the grid to rod fretting wear. The fretting failure of the fuel rod is one of the significant issues recently in the nuclear industry from an economical as well as a safety concern. Thus, it is important to understand the characteristics of cell spring behavior for an irradiated spacer grid. In the present study, the stiffness test and dimensional measurement of cell springs were conducted to investigate the deformation behavior of cell springs of an irradiated spacer grid in a hot cell at IMEF (irradiated materials examination facility) of KAERI

  8. Glacial refugia and recolonization pathways in the brown seaweed Fucus serratus

    NARCIS (Netherlands)

    Hoarau, G.G.; Coyer, J.A.; Veldsink, J.H.; Stam, W.T.; Olsen, J.L.

    The last glacial maximum (20 000-18 000 years ago) dramatically affected extant distributions of virtually all northern European biota. Locations of refugia and postglacial recolonization pathways were examined in Fucus serratus (Heterokontophyta; Fucaceae) using a highly variable intergenic spacer

  9. Implementation of spacer therapy for acute asthma in children.

    LENUS (Irish Health Repository)

    Vandeleur, M

    2009-09-01

    The aim was to develop and implement an evidence based guideline for the treatment of acute asthma using a metered dose inhaler and spacer combination. Children admitted to Cork University Hospital Paediatric Department with acute asthma were identified during two identical 2 month seasonal periods before (2005) and after (2006) implementation of the new guidelines in September 2006. Pre-intervention and post-intervention audits by case note review were performed to determine the impact of and compliance with this evidence-based guideline emphasising patient assessment, spacer delivered bronchodilator and specific discharge criteria. Patients had similar characteristics during the two study periods. There was a raised threshold for admission after guideline implementation with 11\\/52 patients having mild exacerbations in 2006, compared to 21\\/36 in 2005. Duration of admission was less in the post-implementation group for equivalent exacerbation severity e.g. for moderate severity; 28 hours in 2005, 23 hours in 2006. Duration of bronchodilator therapy was shorter in 2006 and more likely to be given by spacer device earlier for equivalent levels of severity e.g. for moderate exacerbations, in 2006 the average length of salbutamol therapy was 18 hours with 12 hours by spacer device, in 2005 the average length of therapy was 25 hours with 3 hours by spacer. There was earlier initiation of oral corticosteroids; the average time to administration was 56 minutes in 2006 and 227 minutes in 2005. There was an improved documentation of asthma education in 2006 e.g. inhaler technique was reviewed in 37\\/52 in 2006, 21\\/35 in 2005 and better use of written action plans.

  10. Effect of spacer grids on CHF in tube bundles

    International Nuclear Information System (INIS)

    Jayanti, Sreenivas; Valette, Michel

    2004-01-01

    Spacers grids are used to support tube bundles in steam generators and in nuclear reactor fuel assemblies. These grids interface with the flow and heat transfer in a number of ways and their effect has been studied by a number of researchers. It is known that generally they have a beneficial effect on critical heat flux (CHF) in typical nuclear reactor assemblies. However, the enhancement obtained depends on the geometric characteristics of the spacer grids as well as on the parameter range in terms of pressure, local mass velocity and quality. In the present study, the problem is approached in the context of a one-dimensional three-field model. Unlike in previous approaches, no specific modeling of the constitutive laws is made to account for spacer effects and only the geometric details such as the reduction in the cross-sectional area and the hydraulic diameter are included in the calculation which is otherwise the same as that for flow through a single tube. It is shown by comparison with literature data that this approach leads to satisfactory prediction of the thermal-hydraulic effects of spacers and that the beneficial effects of spacers on dry out can be manifested only when the entrainment rate is neither too high nor too low. Their effect on reducing the post-dry out wall temperature is also limited to certain cases. The present work has been performed as part of the EDF-CEA Neptune project also supported by the Institut de Radioprotection et de Surete Nucleaire (IRSN, France) and FRAMATOME-ANP. NEPTUNE is a new set of two phase thermalhydraulic computer codes devoted to safety analysis of nuclear power plants. (author)

  11. Effect of a spacer moiety on radiometal labelled Neurotensin derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Mascarin, A.; Valverde, I.E.; Mindt, T.L. [Univ. of Basel Hospital (Switzerland). Div. of Radiopharmaceutical Chemistry

    2013-07-01

    The binding sequence of the regulatory peptide Neurotensin, NT(8-13), represents a promising tumour-specific vector for the development of radiopeptides useful in nuclear oncology for the diagnosis (imaging) and therapy of cancer. A number of radiometal-labelled NT(8-13) derivatives have been reported, however, the effect of the spacer which connects the vector with the radiometal complex has yet not been investigated systematically. Because a spacer moiety can influence potentially important biological characteristics of radiopeptides, we synthesized three [DOTA({sup 177}Lu)]-X-NT(8-13) derivatives and evaluated the effect of a spacer (X) on the physico-chemical properties of the conjugate including lipophilicity, stability, and in vitro receptor affinity and cell internalization. (orig.)

  12. Spacer engineered Trigate SOI TFET: An investigation towards harsh temperature environment applications

    Science.gov (United States)

    Mallikarjunarao; Ranjan, Rajeev; Pradhan, K. P.; Artola, L.; Sahu, P. K.

    2016-09-01

    In this paper, a novel N-channel Tunnel Field Effect Transistor (TFET) i.e., Trigate Silicon-ON-Insulator (SOI) N-TFET with high-k spacer is proposed for better Sub-threshold swing (SS) and OFF-state current (IOFF) by keeping in mind the sensitivity towards temperature. The proposed model can achieve a Sub-threshold swing less than 35 mV/decade at various temperatures, which is desirable for designing low power CTFET for digital circuit applications. In N-TFET source doping has a significant effect on the ON-state current (ION) level; therefore more electrons will tunnel from source to channel region. High-k Spacer i.e., HfO2 is used to enhance the device performance and also it avoids overlapping of transistors in an integrated circuits (IC's). We have designed a reliable device by performing the temperature analysis on Transfer characteristics, Drain characteristics and also on various performance metrics like ON-state current (ION), OFF-state current (IOFF), ION/IOFF, Trans-conductance (gm), Trans-conductance Generation Factor (TGF), Sub-threshold Swing (SS) to observe the applications towards harsh temperature environment.

  13. A one-step reaction for the rapid identification of Lactobacillus mindensis, Lactobacillus panis, Lactobacillus paralimentarius, Lactobacillus pontis and Lactobacillus frumenti using oligonucleotide primers designed from the 16S-23S rRNA intergenic sequences.

    Science.gov (United States)

    Ferchichi, M; Valcheva, R; Prévost, H; Onno, B; Dousset, X

    2008-06-01

    Species-specific primers targeting the 16S-23S ribosomal DNA (rDNA) intergenic spacer region (ISR) were designed to rapidly discriminate between Lactobacillus mindensis, Lactobacillus panis, Lactobacillus paralimentarius, Lactobacillus pontis and Lactobacillus frumenti species recently isolated from French sourdough. The 16S-23S ISRs were amplified using primers 16S/p2 and 23S/p7, which anneal to positions 1388-1406 of the 16S rRNA gene and to positions 207-189 of the 23S rRNA gene respectively, Escherichia coli numbering (GenBank accession number V00331). Clone libraries of the resulting amplicons were constructed using a pCR2.1 TA cloning kit and sequenced. Species-specific primers were designed based on the sequences obtained and were used to amplify the 16S-23S ISR in the Lactobacillus species considered. For all of them, two PCR amplicons, designated as small ISR (S-ISR) and large ISR (L-ISR), were obtained. The L-ISR is composed of the corresponding S-ISR, interrupted by a sequence containing tRNA(Ile) and tRNA(Ala) genes. Based on these sequences, species-specific primers were designed and proved to identify accurately the species considered among 30 reference Lactobacillus species tested. Designed species-specific primers enable a rapid and accurate identification of L. mindensis, L. paralimentarius, L. panis, L. pontis and L. frumenti species among other lactobacilli. The proposed method provides a powerful and convenient means of rapidly identifying some sourdough lactobacilli, which could be of help in large starter culture surveys.

  14. A functional analysis of the spacer of V(DJ recombination signal sequences.

    Directory of Open Access Journals (Sweden)

    Alfred Ian Lee

    2003-10-01

    Full Text Available During lymphocyte development, V(DJ recombination assembles antigen receptor genes from component V, D, and J gene segments. These gene segments are flanked by a recombination signal sequence (RSS, which serves as the binding site for the recombination machinery. The murine Jbeta2.6 gene segment is a recombinationally inactive pseudogene, but examination of its RSS reveals no obvious reason for its failure to recombine. Mutagenesis of the Jbeta2.6 RSS demonstrates that the sequences of the heptamer, nonamer, and spacer are all important. Strikingly, changes solely in the spacer sequence can result in dramatic differences in the level of recombination. The subsequent analysis of a library of more than 4,000 spacer variants revealed that spacer residues of particular functional importance are correlated with their degree of conservation. Biochemical assays indicate distinct cooperation between the spacer and heptamer/nonamer along each step of the reaction pathway. The results suggest that the spacer serves not only to ensure the appropriate distance between the heptamer and nonamer but also regulates RSS activity by providing additional RAG:RSS interaction surfaces. We conclude that while RSSs are defined by a "digital" requirement for absolutely conserved nucleotides, the quality of RSS function is determined in an "analog" manner by numerous complex interactions between the RAG proteins and the less-well conserved nucleotides in the heptamer, the nonamer, and, importantly, the spacer. Those modulatory effects are accurately predicted by a new computational algorithm for "RSS information content." The interplay between such binary and multiplicative modes of interactions provides a general model for analyzing protein-DNA interactions in various biological systems.

  15. How to use an inhaler - no spacer

    Science.gov (United States)

    ... MDI) administration - no spacer; Bronchial nebulizer; Wheezing - nebulizer; Reactive airway - nebulizer; COPD - ... 66. National Asthma Education and Prevention Program website. How to use a metered-dose inhaler. ...

  16. Characterization of feed channel spacer performance using geometries obtained by X-ray computed tomography

    KAUST Repository

    Haaksman, Viktor A.

    2016-09-09

    Spiral-wound membrane modules used in water treatment for water reuse and desalination make use of spacer meshes for keeping the membrane leaves apart and for enhancing the mass transfer. Computational fluid dynamics (CFD) has gained importance in the design of new spacers with optimized hydrodynamic characteristics, but this requires a precise description of the spacer geometry. This study developed a method to obtain accurate three-dimensional (3-D) geometry representations for any given spacer design from X-ray computed tomography (CT) scans. The method revealed that the filaments of industrial spacers have a highly variable cross-section size and shape, which impact the flow characteristics in the feed channel. The pressure drop and friction factors were calculated from numerical simulations on five commercially available feed spacers used in practice. Model solutions compared well to experimental data measured using a flow cell for average velocities up to 0.2 m/s, as used in industrial reverse osmosis and nanofiltration membrane operations. A newly-proposed spacer geometry with alternating strand thickness was tested, which was found to yield a lower pressure drop while being highly efficient in converting the pumping power into membrane shear. Numerical model solutions using CFD with geometries from CT scans were closer to measurements than those obtained using the traditional circular cross-section strand simplification, indicating that CT scans are very well suitable to approximate real feed spacer geometries. By providing detailed insight on the spacer filament shape, CT scans allow better quantification of local distribution of velocity and shear, possibly leading to more accurate estimations of fouling and concentration polarization. © 2016 Elsevier B.V.

  17. Species-specific optical genosensors for the detection of mycotoxigenic Fusarium fungi in food samples

    International Nuclear Information System (INIS)

    Peltomaa, Riikka; Vaghini, Silvia; Patiño, Belén; Benito-Peña, Elena; Moreno-Bondi, María C.

    2016-01-01

    Plant-pathogenic Fusarium species, Fusarium verticillioides and Fusarium proliferatum, are the major producers of fumonisins which are one of the most common mycotoxins found in maize. Herein, we report the development of specific and sensitive genosensors for detecting these two closely related Fusarium species in food samples. The sensors are based on species-specific capture and detection probes, which bind to the intergenic spacer region of rDNA (IGS). Oligonucleotide functionalized magnetic microbeads are used to capture the target DNA which is then detected using biotinylated detection probes and a streptavidin-coupled label. The developed genosensors had detection limits of 1.8 pM and 3.0 pM for F. proliferatum and F. verticillioides, respectively, using synthetic DNA targets. Furthermore, the biosensors were used to analyze natural fungal contamination of commercial maize samples. After amplification of the genomic DNA the sensors detected the presence of the fungi, in accordance with previous results obtained with PCR. No cross-reactivity between F. verticillioides and F. proliferatum, or other fungi species tested, was observed. The developed biosensors can provide a valuable tool to evaluate the potential for mycotoxin contamination in conditions where detection of mycotoxins directly is challenging. - Highlights: • Optical genosensors detect fumonisin producing Fusarium species in maize samples. • Oligonucleotide probes designed on the intergenic spacer region of rDNA can distinguish between closely related species. • Sandwich hybridization assay with magnetic microbeads allows species-specific detection of Fusarium spp. directly from PCR.

  18. Species-specific optical genosensors for the detection of mycotoxigenic Fusarium fungi in food samples

    Energy Technology Data Exchange (ETDEWEB)

    Peltomaa, Riikka; Vaghini, Silvia [Department of Analytical Chemistry, Faculty of Chemistry, Complutense University, Ciudad Universitaria s/n, Madrid 28040 (Spain); Patiño, Belén [Department of Microbiology III, Faculty of Biology, Complutense University, Ciudad Universitaria s/n, Madrid 28040 (Spain); Benito-Peña, Elena, E-mail: elenabp@ucm.es [Department of Analytical Chemistry, Faculty of Chemistry, Complutense University, Ciudad Universitaria s/n, Madrid 28040 (Spain); Moreno-Bondi, María C., E-mail: mcmbondi@ucm.es [Department of Analytical Chemistry, Faculty of Chemistry, Complutense University, Ciudad Universitaria s/n, Madrid 28040 (Spain)

    2016-09-07

    Plant-pathogenic Fusarium species, Fusarium verticillioides and Fusarium proliferatum, are the major producers of fumonisins which are one of the most common mycotoxins found in maize. Herein, we report the development of specific and sensitive genosensors for detecting these two closely related Fusarium species in food samples. The sensors are based on species-specific capture and detection probes, which bind to the intergenic spacer region of rDNA (IGS). Oligonucleotide functionalized magnetic microbeads are used to capture the target DNA which is then detected using biotinylated detection probes and a streptavidin-coupled label. The developed genosensors had detection limits of 1.8 pM and 3.0 pM for F. proliferatum and F. verticillioides, respectively, using synthetic DNA targets. Furthermore, the biosensors were used to analyze natural fungal contamination of commercial maize samples. After amplification of the genomic DNA the sensors detected the presence of the fungi, in accordance with previous results obtained with PCR. No cross-reactivity between F. verticillioides and F. proliferatum, or other fungi species tested, was observed. The developed biosensors can provide a valuable tool to evaluate the potential for mycotoxin contamination in conditions where detection of mycotoxins directly is challenging. - Highlights: • Optical genosensors detect fumonisin producing Fusarium species in maize samples. • Oligonucleotide probes designed on the intergenic spacer region of rDNA can distinguish between closely related species. • Sandwich hybridization assay with magnetic microbeads allows species-specific detection of Fusarium spp. directly from PCR.

  19. Effect of plastic spacer handling on salbutamol lung deposition in asthmatic children

    DEFF Research Database (Denmark)

    Lipworth, Brian J; Lee, Daniel K C; Anhøj, Jacob

    2002-01-01

    AIMS: To study the effects of electrostatics in a plastic spacer on the lung deposition of salbutamol in asthmatic children. METHODS: Twenty-five children (5-12 years) with mild asthma were given salbutamol hydrofluoroalkane pressurized metered dose inhaler 400 micro g via a 750 ml plastic spacer...... on separate days. Blood samples were taken for plasma salbutamol at 5, 10, 15 and 20 min after inhalation to measure lung bioavailability as a surrogate for relative lung dose. With immediate inhalation following actuation, a new rinsed spacer (NewRinsed ) was compared with a used spacer after repeated daily...... log transformed and expressed as geometric mean fold difference for the average plasma salbutamol concentration (Cav) over 20 min. RESULTS: There were significant differences (P NewRinsed 1.92 fold (95% CI 1.15, 3...

  20. Optimized spacer layer thickness for plasmonic-induced enhancement of photocurrent in a-Si:H

    Energy Technology Data Exchange (ETDEWEB)

    Saleh, Z. M., E-mail: zaki.saleh@aauj.edu, E-mail: zakimsaleh@yahoo.com; Nasser, H.; Özkol, E.; Günöven, M.; Abak, K. [Middle East Technical University, Center for Solar Energy Research and Applications (GÜNAM) (Turkey); Canli, S. [Middle East Technical University, Central Laboratory (Turkey); Bek, A.; Turan, R. [Middle East Technical University, Center for Solar Energy Research and Applications (GÜNAM) (Turkey)

    2015-10-15

    Plasmonic interfaces consisting of silver nanoparticles of different sizes (50–100 nm) have been processed by the self-assembled dewetting technique and integrated to hydrogenated amorphous silicon (a-Si:H) using SiNx spacer layers to investigate the dependence of optical trapping enhancement on spacer layer thickness through the enhancements in photocurrent. Samples illuminated from the a-Si:H side exhibit a localized surface plasmon resonance (LSPR) that is red-shifted with the increasing particle size and broadened into the red with the increasing spacer layer thickness. The photocurrent measured in a-Si:H is not only consistent with the red-shift and broadening of the LSPR, but exhibits critical dependence on the spacer layer thickness also. The samples with plasmonic interfaces and a SiNx spacer layer exhibit appreciable enhancement of photocurrent compared with flat a-Si:H reference depending on the size of the Ag nanoparticle. Simulations conducted on one-dimensional square structures exhibit electric fields that are localized near the plasmonic structures but extend appreciably into the higher refractive index a-Si:H. These simulations produce a clear red-shift and broadening of extinction spectra for all spacer layer thicknesses and predict an enhancement in photocurrent in agreement with experimental results. The spectral dependence of photocurrent for six plasmonic interfaces with different Ag nanoparticle sizes and spacer layer thicknesses are correlated with the optical spectra and compared with the simulations to predict an optimal spacer layer thickness.

  1. Shelf life of pie caps with biodegradable films as spacers

    Directory of Open Access Journals (Sweden)

    Daniela Verónica Escobar Gianni

    2013-01-01

    Full Text Available Commonly pie caps at market use polyethylene films as spacers between them. This paper studies the conventional spacers replacement with edible and biodegradable films made with whey protein isolate (WPI and potassium sorbate as a preservative. Besides facilitating the separation of pie caps, with this application is intended to increase their shelf life. The films made by the compression molding method were used as spacers in pie caps without preservative in their formula (A and with preservative (B and they were compared with conventional polyethylene spacers (C. During four months, monthly sensory, microbiological and physicochemical (humidity evaluations were done on the pie caps, together with humidity and solubility evaluations of the films. None of the samples showed microbiological or sensory deterioration. The sensory attributes showed no or slight difference in study time. Between samples the differences were minor: the best scores were for sample A in color, sample C in flavor, and samples B and C in texture and overall liking. The edible films have an interesting potential for this application, although studies in disguise the flavor of serum should be done.

  2. Hot fuel examination facility element spacer wire-wrap machine

    International Nuclear Information System (INIS)

    Tobias, D.A.; Sherman, E.K.

    1989-01-01

    Nondestructive examinations of irradiated experimental fuel elements conducted in the Argonne National Laboratory Hot Fuel Examination Facility/North (HFEF/N) at the Idaho National Engineering Laboratory include laser and contact profilometry (element diameter measurements), electrical eddy-current testing for cladding and thermal bond defects, bow and length measurements, neutron radiography, gamma scanning, remote visual exam, and photography. Profilometry was previously restricted to spiral profilometry of the element to prevent interference with the element spacer wire wrapped in a helix about the Experimental Breeder Reactor II (EBR-II)-type fuel element from end to end. By removing the spacer wire prior to conducting profilometry examination, axial profilometry techniques may be used, which are considerably faster than spiral techniques and often result in data acquisition more important to experiment sponsors. Because the element must often be reinserted into the nuclear reactor (EBR-II) for additional irradiation, however, the spacer wire must be reinstalled on the highly irradiated fuel element by remote means after profilometry of the wireless elements. The element spacer wire-wrap machine developed at HFEF is capable of helically wrapping fuel elements with diameters up to 1.68 cm (0.660 in.) and 2.44-m (96-in.) lengths. The machine can accommodate almost any desired wire pitch length by simply inserting a new wrapper gear module

  3. Knitting Technologies And Tensile Properties Of A Novel Curved Flat-Knitted Three-Dimensional Spacer Fabrics

    Directory of Open Access Journals (Sweden)

    Li Xiaoying

    2015-09-01

    Full Text Available This paper introduces a knitting technique for making innovative curved three-dimensional (3D spacer fabrics by the computer flat-knitting machine. During manufacturing, a number of reinforcement yarns made of aramid fibres are inserted into 3D spacer fabrics along the weft direction to enhance the fabric tensile properties. Curved, flat-knitted 3D spacer fabrics with different angles (in the warp direction were also developed. Tensile tests were carried out in the weft and warp directions for the two spacer fabrics (with and without reinforcement yarns, and their stress–strain curves were compared. The results showed that the reinforcement yarns can reduce the fabric deformation and improve tensile stress and dimensional stability of 3D spacer fabrics. This research can help the further study of 3D spacer fabric when applied to composites.

  4. Using cathode spacers to minimize reactor size in air cathode microbial fuel cells

    KAUST Repository

    Yang, Qiao

    2012-04-01

    Scaling up microbial fuel cells (MFCs) will require more compact reactor designs. Spacers can be used to minimize the reactor size without adversely affecting performance. A single 1.5mm expanded plastic spacer (S1.5) produced a maximum power density (973±26mWm -2) that was similar to that of an MFC with the cathode exposed directly to air (no spacer). However, a very thin spacer (1.3mm) reduced power by 33%. Completely covering the air cathode with a solid plate did not eliminate power generation, indicating oxygen leakage into the reactor. The S1.5 spacer slightly increased columbic efficiencies (from 20% to 24%) as a result of reduced oxygen transfer into the system. Based on operating conditions (1000ς, CE=20%), it was estimated that 0.9Lh -1 of air would be needed for 1m 2 of cathode area suggesting active air flow may be needed for larger scale MFCs. © 2012 Elsevier Ltd.

  5. Update on Pneumocystis carinii f. sp. hominis Typing Based on Nucleotide Sequence Variations in Internal Transcribed Spacer Regions of rRNA Genes

    Science.gov (United States)

    Lee, Chao-Hung; Helweg-Larsen, Jannik; Tang, Xing; Jin, Shaoling; Li, Baozheng; Bartlett, Marilyn S.; Lu, Jang-Jih; Lundgren, Bettina; Lundgren, Jens D.; Olsson, Mats; Lucas, Sebastian B.; Roux, Patricia; Cargnel, Antonietta; Atzori, Chiara; Matos, Olga; Smith, James W.

    1998-01-01

    Pneumocystis carinii f. sp. hominis isolates from 207 clinical specimens from nine countries were typed based on nucleotide sequence variations in the internal transcribed spacer regions I and II (ITS1 and ITS2, respectively) of rRNA genes. The number of ITS1 nucleotides has been revised from the previously reported 157 bp to 161 bp. Likewise, the number of ITS2 nucleotides has been changed from 177 to 192 bp. The number of ITS1 sequence types has increased from 2 to 15, and that of ITS2 has increased from 3 to 14. The 15 ITS1 sequence types are designated types A through O, and the 14 ITS2 types are named types a through n. A total of 59 types of P. carinii f. sp. hominis were found in this study. PMID:9508304

  6. Nuclear reactor fuel assembly spacer grids

    International Nuclear Information System (INIS)

    Jabsen, F.S.

    1977-01-01

    Designs of nuclear reactor fuel assembly spacer grids for supporting and spacing fuel elements are described which do not utilize resilient grid plate protrusions in the peripheral band but retain the advantages inherent in the combination resilient and rigid protrusion cells. (U.K.)

  7. Suppression of subthreshold characteristics variation for junctionless multigate transistors using high-k spacers

    International Nuclear Information System (INIS)

    Lou, Haijun; Zhang, Baili; Li, Dan; Lin, Xinnan; He, Jin; Chan, Mansun

    2015-01-01

    In this work, the high-k spacer is proposed to suppress the subthreshold characteristics variation of junctionless multigate transistor (JMT) with non-ideal sidewall angle for the first time. It is demonstrated that the variation of subthreshold characteristics induced by the changing sidewall angle is efficiently suppressed by high-k spacers due to the enhanced corner effect through the fringe capacitance, and the electrostatic integrity of JMTs is also improved at sub-22 nm gate length. Two key parameters of high-k spacer, the thickness and length, have been optimized in terms of the suppression of subthreshold characteristics variation. Then their optimal values are proposed. The benefit of high-k spacer makes JMTs more scalable. (paper)

  8. Primers for Phylogeny Reconstruction in Bignonieae (Bignoniaceae Using Herbarium Samples

    Directory of Open Access Journals (Sweden)

    Alexandre R. Zuntini

    2013-08-01

    Full Text Available Premise of the study: New primers were developed for Bignonieae to enable phylogenetic studies within this clade using herbarium samples. Methods and Results: Internal primers were designed based on available sequences of the plastid ndhF gene and the rpl32-trnL intergenic spacer region, and the nuclear gene PepC. The resulting primers were used to amplify DNA extracted from herbarium materials. High-quality data were obtained from herbarium samples up to 53 yr old. Conclusions: The standardized methodology allows the inclusion of herbarium materials as alternative sources of DNA for phylogenetic studies in Bignonieae.

  9. Phenotypic and genetic diversity of Saccharomyces contaminants isolated from lager breweries and their phylogenetic relationship with brewing yeasts

    DEFF Research Database (Denmark)

    Jespersen, Lene; Kühle, Alis Van der Aa; Petersen, Kamilla M.

    2000-01-01

    -amplified intergenic transcribed spacer (ITS) regions. Chromosome length polymorphism (CLP) was evident among the Saccharomyces brewing contaminants with chromosome profiles typical of Saccharomyces sensu stricto. Based upon cluster analysis of their chromosome profiles the majority of the brewing contaminants could...... be grouped as either S. cerevisiae or S. pastorianus/S. bayanus. Further, the technique was able to differentiate between almost all brewing contaminants and to separate them from any specific lager brewing yeast. The diversity of the Saccharomyces brewing contaminants clearly demonstrated by their CLP...... in the SaccharomYces brewing contaminants indicate their adaptation to a maltose-enriched environment....

  10. BWR fuel assembly with improved spacer and fuel bundle design for enhanced thermal-hydraulic performance

    International Nuclear Information System (INIS)

    Mildrum, C.M.; Taleyarkhan, R.P.

    1987-01-01

    In a fuel assembly having a bundle of elongated fuel rods disposed in side-by-side relationship so as to form an array of spaced fuel rods, an outer tubular flow channel surrounding the fuel rods so as to direct flow of coolant/moderator fluid along the fuel rods, a hollow water cross extending centrally through and interconnected with the outer flow channel so as to divide the channel into separate compartments and the bundle of fuelrods into a plurality of mini-bundles thereof being disposed in the compartments, and spacers axially displaced along the fuel rods in each of the mini-bundles thereof. Each spacer is composed of inner and outer means which together define spacer cells at corner, side and interior locations of the spacer and have respective protrusions formed thereon which extend into cells so as to maintain the fuel rods received through the spacer cells in laterally spaced relationships. The improvement is described which comprises: (a) a generally uniform poison coating within at least a majority of the fuel rods; (b) a predetermined pattern of fuel enrichment with respect to the fuel rods of each mini-bundle thereof which together with the uniform poison coating within the fuel rods ensures that the packing powers of the fuel rods in the corner and side cells of the spacers are less than the peaking power of a leading one of the fuel rods in the interior cells of the spacers; and (c) each of the fuel rods being received through the cells of each spacer having a diametric size smaller than that of each of the fuel rods received through the side and interior cells of each spacer, the diametric sizes of each of the fuel rods received through the side and interior cells of each spacer being generally equal

  11. Repeated reunions and splits feature the highly dynamic evolution of 5S and 35S ribosomal RNA genes (rDNA) in the Asteraceae family

    Czech Academy of Sciences Publication Activity Database

    Garcia, S.; Panero, J.L.; Široký, Jiří; Kovařík, Aleš

    2010-01-01

    Roč. 10, č. 176 (2010), s. 1-18 ISSN 1471-2229 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : organization of rDNA unit * intergenic spacer * Asteraceae Subject RIV: BO - Biophysics Impact factor: 4.085, year: 2010

  12. Spacer grid for a nuclear reactor fuel assembly

    International Nuclear Information System (INIS)

    Jabsen, F.S.

    1978-01-01

    The spacer grid consists of pairs of plates forming rectangular cells and enclosing the cylindrical fuel assemblies. They have got rigid as well as elastic projections extending into the cells and holding the fuel assemblies. Additional pairs of plates are arranged in about the center of the grid of plates. They have got only elastic projections extending on both sides of the plates into one cell each. This spacer grid may be used for reactor cores with and without fuel channels. By the combination of spring-elastic and rigid projections there is obtained a reinforced outer tie. Hydraulic pressure losses, parasitic neutron capture, and hot spots are essentially reduced. (DG) [de

  13. Modeling the effect of spacers and biofouling on forward osmosis performance

    KAUST Repository

    Mosqueira Santillán, María José

    2014-11-01

    Currently, the most utilized desalination technology is reverse osmosis (RO), where a membrane is used as a physical barrier to separate the salts from the seawater, using high hydraulic pressure as driving force. A major problem in RO systems is biofouling, caused by severe growth of bacterial biofilms. Both, the need of an external energy input, as well as biofouling, impose a high cost on RO operation. Forward osmosis (FO) is an alternative membrane process that uses an osmotic pressure difference as driving force. FO uses a concentrated draw solution to generate high osmotic pressure, which extracts water across a semi permeable membrane from a feed solution. One of the main advantages of FO is the limited amount of external energy required to extract water from the feed solution. The objective of this research is the assessment of the impact of spacers, separating the membrane sheets, and biofouling on the FO system performance. This type of studies allow the optimization of membrane devices and operational conditions. For this, a two dimensional numerical model for FO systems was developed using computational fluid dynamics (CFD). This model allowed the evaluation of the impact of (i) spacers and (ii) biofilm, and (iii) the combined impact of spacers and biofilm on the performance of FO systems. The results obtained showed that the presence of spacers improved the performance of FO systems. Cavity configuration spacer gave the higher water flux across the membrane in clean systems; whereas for biofouled systems, the submerged configuration showed a better performance. In absence of spacers, the thickness or amount of biofilm is inversely proportional with the water flux. Furthermore, membrane surface coverage of the biofilm is more important than the amount of biofilm in terms of the impact on the performance. The numerical model can be adapted with other parameters (e.g. membrane and spacer thickness, feed and draw solution, solution concentration, etc.) to

  14. Biofouling patterns in spacer filled channels: High resolution imaging for characterization of heterogeneous biofilms

    KAUST Repository

    Staal, Marc

    2017-08-15

    Biofilms develop in heterogeneous patterns at a µm scale up to a cm scale, and patterns become more pronounced when biofilms develop under complex hydrodynamic flow regimes. Spatially heterogeneous biofilms are especially known in spiral wound reverse osmosis (RO) and nanofiltration (NF) membrane filtration systems used for desalination and wastewater reuse to produce high quality (drinking) water. These spiral wound membrane modules contain mesh-like spacer structures used to create an intermembrane space and improve water mixing. Spacers create inhomogeneous water flow patterns resulting in zones favouring biofilm growth, possibly leading to biofouling thus hampering water production. Oxygen sensing planar optodes were used to visualize variations in oxygen decrease rates (ODR). ODR is an indication of biofilm activity. In this study, ODR images of multiple repetitive spacer areas in a membrane fouling simulator were averaged to produce high resolution, low noise ODR images. Averaging 40 individual spacer areas improved the ODR distribution image significantly and allowed comparison of biofilm patterning over a spacer structure at different positions in an RO filter. This method clearly showed that most active biofilm accumulated on and in direct vicinity of the spacer. The averaging method was also used to calculate the deviation of ODR patterning from individual spacer areas to the average ODR pattern, proposing a new approach to determine biofilm spatial heterogeneity. This study showed that the averaging method can be applied and that the improved, averaged ODR images can be used as an analytical, in-situ, non-destructive method to assess and quantify the effect of membrane installation operational parameters or different spacer geometries on biofilm development in spiral wound membrane systems characterized by complex hydrodynamic conditions.

  15. Numerical Simulation for Flow Distribution in ACE7 Fuel Assemblies affected by a Spacer Grid Deformation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jongpil; Jeong, Ji Hwan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    In spite of various efforts to understand hydraulic phenomena in a rod bundle containing deformed rods due to swelling and/or ballooning of clad, the studies for flow blockage due to spacer grid deformation have been limited. In the present work, 3D CFD analysis for flow blockage was performed to evaluate coolant flow within ACE7 fuel assemblies (FAs) containing a FA affected by a spacer grid deformation. The real geometry except for inner grids was used in the simulation and the region including inner grid was replaced by porous media. In the present work, the numerical simulation was performed to predict coolant flow within ACE7 FAs affected by a Mid grid deformation. The 3D CFD result shows that approximately 60 subchannel hydraulic diameter is required to fully recover coolant flow under normal operating condition.

  16. 5 X 5 rod bundle flow field measurements downstream a PWR spacer grid

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Higor F.P.; Silva, Vitor V A.; Santos, André A.C.; Veloso, Maria A.F., E-mail: higorfabiano@gmail.com, E-mail: mdora@nuclear.ufmg.br, E-mail: vitors@cdtn.br, E-mail: aacs@cdtn.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil); Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2017-07-01

    The spacer grids are structures present in nuclear fuel assembly of Pressurized Water Reactors (PWR). They play an important structural role and also assist in heat removal through the assembly by promoting increased turbulence of the flow. Understanding the flow dynamics downstream the spacer grid is paramount for fuel element design and analysis. This paper presents water flow velocity profiles measurements downstream a spacer grid in a 5 x 5 rod bundle test rig with the objective of highlighting important fluid dynamic behavior near the grid and supplying data for CFD simulation validation. These velocity profiles were obtained at two different heights downstream the spacer grid using a LDV (Laser Doppler Velocimetry) through the top of test rig. The turbulence intensities and patterns of the swirl and cross flow were evaluated. The tests were conducted for Reynolds numbers ranging from 1.8 x 10{sup 4} to 5.4 x 10{sup 4}. This experimental research was carried out in thermo-hydraulics laboratory of Nuclear Technology Development Center – CDTN. Results show great repeatability and low uncertainties (< 1.24 %). Details of the flow field show how the mixture and turbulence induced by the spacer grid quickly decays downstream the spacer grid. It is shown that the developed methodology can supply high resolution low uncertainty results that can be used for validation of CFD simulations. (author)

  17. 5 X 5 rod bundle flow field measurements downstream a PWR spacer grid

    International Nuclear Information System (INIS)

    Castro, Higor F.P.; Silva, Vitor V A.; Santos, André A.C.; Veloso, Maria A.F.

    2017-01-01

    The spacer grids are structures present in nuclear fuel assembly of Pressurized Water Reactors (PWR). They play an important structural role and also assist in heat removal through the assembly by promoting increased turbulence of the flow. Understanding the flow dynamics downstream the spacer grid is paramount for fuel element design and analysis. This paper presents water flow velocity profiles measurements downstream a spacer grid in a 5 x 5 rod bundle test rig with the objective of highlighting important fluid dynamic behavior near the grid and supplying data for CFD simulation validation. These velocity profiles were obtained at two different heights downstream the spacer grid using a LDV (Laser Doppler Velocimetry) through the top of test rig. The turbulence intensities and patterns of the swirl and cross flow were evaluated. The tests were conducted for Reynolds numbers ranging from 1.8 x 10"4 to 5.4 x 10"4. This experimental research was carried out in thermo-hydraulics laboratory of Nuclear Technology Development Center – CDTN. Results show great repeatability and low uncertainties (< 1.24 %). Details of the flow field show how the mixture and turbulence induced by the spacer grid quickly decays downstream the spacer grid. It is shown that the developed methodology can supply high resolution low uncertainty results that can be used for validation of CFD simulations. (author)

  18. Research report on development of spacer grid strap for AFA 3G fuel assembly

    International Nuclear Information System (INIS)

    Ye Yuandong

    2004-11-01

    The current development and tendency for fuel assemblies being of low leakage, high burn-up and long cycle fuel reload in the world are presented, and the necessity and feasibility to develop the spacer grid for high burn-up fuel assembly are elaborated. Considering all the activities in implementing of spacer grid and the technical difficulties in machining of tools, the major technological processes are introduced; the research program and the approaches to develop the spacer grid while research targets and overall schedule are defined and some key technical points and applicable practices are discussed. Finally the requirements and the conditions necessary for developing of spacer grid are proposed. (authors)

  19. A functional analysis of the spacer of V(D)J recombination signal sequences.

    Science.gov (United States)

    Lee, Alfred Ian; Fugmann, Sebastian D; Cowell, Lindsay G; Ptaszek, Leon M; Kelsoe, Garnett; Schatz, David G

    2003-10-01

    During lymphocyte development, V(D)J recombination assembles antigen receptor genes from component V, D, and J gene segments. These gene segments are flanked by a recombination signal sequence (RSS), which serves as the binding site for the recombination machinery. The murine Jbeta2.6 gene segment is a recombinationally inactive pseudogene, but examination of its RSS reveals no obvious reason for its failure to recombine. Mutagenesis of the Jbeta2.6 RSS demonstrates that the sequences of the heptamer, nonamer, and spacer are all important. Strikingly, changes solely in the spacer sequence can result in dramatic differences in the level of recombination. The subsequent analysis of a library of more than 4,000 spacer variants revealed that spacer residues of particular functional importance are correlated with their degree of conservation. Biochemical assays indicate distinct cooperation between the spacer and heptamer/nonamer along each step of the reaction pathway. The results suggest that the spacer serves not only to ensure the appropriate distance between the heptamer and nonamer but also regulates RSS activity by providing additional RAG:RSS interaction surfaces. We conclude that while RSSs are defined by a "digital" requirement for absolutely conserved nucleotides, the quality of RSS function is determined in an "analog" manner by numerous complex interactions between the RAG proteins and the less-well conserved nucleotides in the heptamer, the nonamer, and, importantly, the spacer. Those modulatory effects are accurately predicted by a new computational algorithm for "RSS information content." The interplay between such binary and multiplicative modes of interactions provides a general model for analyzing protein-DNA interactions in various biological systems.

  20. Microbial fuel cells with an integrated spacer and separate anode and cathode modules

    KAUST Repository

    He, Weihua

    2016-01-01

    A new type of scalable MFC was developed based on using alternating graphite fiber brush array anode modules and dual cathode modules in order to simplify construction, operation, and maintenance of the electrodes. The modular MFC design was tested with a single (two-sided) cathode module with a specific surface area of 29 m2 m−3 based on a total liquid volume (1.4 L; 20 m2 m−3 using the total reactor volume of 2 L), and two brush anode modules. Three different types of spacers were used in the cathode module to provide structural stability, and enhance air flow relative to previous cassette (combined anode–cathode) designs: a low-profile wire spacer; a rigid polycarbonate column spacer; and a flexible plastic mesh spacer. The best performance was obtained using the wire spacer that produced a maximum power density of 1100 ± 10 mW m−2 of cathode (32 ± 0.3 W m−3 based on liquid volume) with an acetate-amended wastewater (COD = 1010 ± 30 mg L−1), compared to 1010 ± 10 mW m−2 for the column and 650 ± 20 mW m−2 for the mesh spacers. Anode potentials were unaffected by the different types of spacers. Raw domestic wastewater produced a maximum of 400 ± 8 mW m−2 under fed batch conditions (wire-spacers), which is one of the highest power densities for this fuel. Over time the maximum power was reduced to 300 ± 10 mW m−2 and 275 ± 7 mW m−2 for the two anode compartments, with only slightly less power of 250 ± 20 mW m−2 obtained under continuous flow conditions. In fixed-resistance tests, the average COD removal was 57 ± 5% at a hydraulic retention time of 8 h. These results show that this modular MFC design can both simplify reactor construction and enable relatively high power generation from even relatively dilute wastewater.

  1. Effect of plastic spacer handling on salbutamol lung deposition in asthmatic children

    DEFF Research Database (Denmark)

    Lipworth, Brian J; Lee, Daniel K C; Anhøj, Jacob

    2002-01-01

    AIMS: To study the effects of electrostatics in a plastic spacer on the lung deposition of salbutamol in asthmatic children. METHODS: Twenty-five children (5-12 years) with mild asthma were given salbutamol hydrofluoroalkane pressurized metered dose inhaler 400 micro g via a 750 ml plastic spacer...

  2. Chalcone Synthase Gene Lineage Diversification confirms allopolyploid evolutionary relationships of European Rostrate Violets

    NARCIS (Netherlands)

    Hof, van den K.; Berg, van den R.G.; Gravendeel, B.

    2008-01-01

    Phylogenetic relationships among and within the subsections of the genus Viola are still far from resolved. We present the first organismal phylogeny of predominantly western European species of subsection Rostratae based on the plastid trnS¿trnG intron and intergenic spacer and the nuclear low-copy

  3. Concerted evolution of 18-5.8-26S rDNA repeats in Nicotiana allotetraploids

    Czech Academy of Sciences Publication Activity Database

    Kovařík, Aleš; Matyášek, Roman; Lim, K. Y.; Skalická, Kamila; Koukalová, Blažena; Knapp, S.; Chase, M. W.; Leitch, A. R.

    2004-01-01

    Roč. 82, č. 4 (2004), s. 615-625 ISSN 0024-4066 R&D Projects: GA AV ČR IBS5004010 Institutional research plan: CEZ:AV0Z5004920 Keywords : gene conversion * intergenic spacer diversity * intergenomic interaction Subject RIV: BO - Biophysics Impact factor: 1.935, year: 2004

  4. Bimetallic spacer means for a nuclear fuel assembly

    International Nuclear Information System (INIS)

    Anthony, A.J.

    1981-01-01

    A bimetallic spacer means designed to be cooperatively associated with a nuclear fuel assembly and operative to resist the occurrence of in-reactor bowing of the nuclear fuel assembly. The subject bimetallic spacer means in accord with one embodiment of the invention includes a member formed, at least principally, of Zircaloy to which are attached a plurality of stainless steel strips. The latter stainless steel strips are located on the external surface of the Zircaloy member and with the major axis of each of the plurality of stainless steel strips extending substantially perpendicular to the major axis of the Zircaloy member. In accord with another embodiment of the invention, the subject bimetallic spacer means includes a member formed at least principally of Zircaloy to which a plurality of stainless steel strips are attached so as to be positioned thereon externally thereof and with the major axis of each of the plurality of stainless steel strips extending substantially parallel to the major axis of the Zircaloy member. In accord with a further embodiment of the invention, the stainless steel strips are attached to preselected members, each embodying at least a cladding of Zircaloy, which are located in the rows of fuel rods that define the perimeter of the fuel matrix of the nuclear fuel assembly. In each of the embodiments, the stainless steel strips during power production expand outwardly to a greater extent than do the members to which the stainless steel strips are attached, thereby forming stiff springs which abut against like bimetallic spacer means with which the other nuclear fuel assemblies are provided in a given nuclear reactor core to thus prevent the occurrence of in-reactor bowing of the nuclear fuel assemblies. Namely, the stainless steel strips expand laterally relative to the fuel assembly and thereby occupy the space adjacent to the external surface of the fuel assembly

  5. The identification of two Trypanosoma cruzi I genotypes from domestic and sylvatic transmission cycles in Colombia based on a single polymerase chain reaction amplification of the spliced-leader intergenic region

    Directory of Open Access Journals (Sweden)

    Lina Marcela Villa

    2013-11-01

    Full Text Available A single polymerase chain reaction (PCR reaction targeting the spliced-leader intergenic region of Trypanosoma cruzi I was standardised by amplifying a 231 bp fragment in domestic (TcIDOM strains or clones and 450 and 550 bp fragments in sylvatic strains or clones. This reaction was validated using 44 blind coded samples and 184 non-coded T. cruzi I clones isolated from sylvatic triatomines and the correspondence between the amplified fragments and their domestic or sylvatic origin was determined. Six of the nine strains isolated from acute cases suspected of oral infection had the sylvatic T. cruzi I profile. These results confirmed that the sylvatic T. cruzi I genotype is linked to cases of oral Chagas disease in Colombia. We therefore propose the use of this novel PCR reaction in strains or clones previously characterised as T. cruzi I to distinguish TcIDOMfrom sylvatic genotypes in studies of transmission dynamics, including the verification of population selection within hosts or detection of the frequency of mixed infections by both T. cruzi I genotypes in Colombia.

  6. Membrane-based oligonucleotide array developed from multiple markers for the detection of many Phytophthora species.

    Science.gov (United States)

    Chen, Wen; Djama, Zeinab Robleh; Coffey, Michael D; Martin, Frank N; Bilodeau, Guillaume J; Radmer, Lorien; Denton, Geoff; Lévesque, C André

    2013-01-01

    Most Phytophthora spp. are destructive plant pathogens; therefore, effective monitoring and accurate early detection are important means of preventing potential epidemics and outbreaks of diseases. In the current study, a membrane-based oligonucleotide array was developed that can detect Phytophthora spp. reliably using three DNA regions; namely, the internal transcribed spacer (ITS), the 5' end of cytochrome c oxidase 1 gene (cox1), and the intergenic region between cytochrome c oxidase 2 gene (cox2) and cox1 (cox2-1 spacer). Each sequence data set contained ≈250 sequences representing 98 described and 15 undescribed species of Phytophthora. The array was validated with 143 pure cultures and 35 field samples. Together, nonrejected oligonucleotides from all three markers have the ability to reliably detect 82 described and 8 undescribed Phytophthora spp., including several quarantine or regulated pathogens such as Phytophthora ramorum. Our results showed that a DNA array containing signature oligonucleotides designed from multiple genomic regions provided robustness and redundancy for the detection and differentiation of closely related taxon groups. This array has the potential to be used as a routine diagnostic tool for Phytophthora spp. from complex environmental samples without the need for extensive growth of cultures.

  7. The complete mitochondrial genome of the land snail Cornu aspersum (Helicidae: Mollusca: intra-specific divergence of protein-coding genes and phylogenetic considerations within Euthyneura.

    Directory of Open Access Journals (Sweden)

    Juan Diego Gaitán-Espitia

    Full Text Available The complete sequences of three mitochondrial genomes from the land snail Cornu aspersum were determined. The mitogenome has a length of 14050 bp, and it encodes 13 protein-coding genes, 22 transfer RNA genes and two ribosomal RNA genes. It also includes nine small intergene spacers, and a large AT-rich intergenic spacer. The intra-specific divergence analysis revealed that COX1 has the lower genetic differentiation, while the most divergent genes were NADH1, NADH3 and NADH4. With the exception of Euhadra herklotsi, the structural comparisons showed the same gene order within the family Helicidae, and nearly identical gene organization to that found in order Pulmonata. Phylogenetic reconstruction recovered Basommatophora as polyphyletic group, whereas Eupulmonata and Pulmonata as paraphyletic groups. Bayesian and Maximum Likelihood analyses showed that C. aspersum is a close relative of Cepaea nemoralis, and with the other Helicidae species form a sister group of Albinaria caerulea, supporting the monophyly of the Stylommatophora clade.

  8. Application of a hydrogel spacer for postoperative salvage radiotherapy of prostate cancer

    International Nuclear Information System (INIS)

    Pinkawa, Michael; Schubert, Carolin; Escobar-Corral, Nuria; Holy, Richard; Eble, Michael J.

    2015-01-01

    In contrast to primary radiotherapy, no reports are available for a hydrogel spacer application in postoperative salvage radiotherapy for prostate cancer. A 77-year-old patient presented 20 years after radical prostatectomy with a digitally palpable local recurrence at the urethrovesical anastomosis (PSA 5.5 ng/ml). The hydrogel spacer (10 ml, SpaceOAR trademark) was injected between the local recurrence and rectal wall under transrectal ultrasound guidance. Treatment planning was performed with an intensity-modulated technique up to a total dose of 76 Gy in 2-Gy fractions. The same planning was performed based on computed tomography before spacer injection for comparison. The local recurrence, initially directly on the rectal wall, could be displaced more than 1 cm from the rectal wall after hydrogel injection. With a mean total dose of 76 Gy to the planning target volume, rectal wall volumes included in the 70 Gy, 60 Gy, 50 Gy isodoses were 0 cm 3 , 0 cm 3 , and 0.4 cm 3 with a spacer and 2.9 cm 3 , 4.5 cm 3 , and 6.2 cm 3 without a spacer, respectively. The patient reported rectal urgency during radiotherapy, completely resolving after the end of treatment. The PSA level was 5.4 ng/ml a week before the end of radiotherapy and dropped to 0.9 ng/ml 5 months after radiotherapy. A hydrogel spacer was successfully applied for dose-escalated radiotherapy in a patient with macroscopic local prostate cancer recurrence at the urethrovesical anastomosis to decrease the dose at the rectal wall. This option can be considered in specifically selected patients. (orig.) [de

  9. Genotypic Characterization of Bradyrhizobium Strains Nodulating Endemic Woody Legumes of the Canary Islands by PCR-Restriction Fragment Length Polymorphism Analysis of Genes Encoding 16S rRNA (16S rDNA) and 16S-23S rDNA Intergenic Spacers, Repetitive Extragenic Palindromic PCR Genomic Fingerprinting, and Partial 16S rDNA Sequencing

    Science.gov (United States)

    Vinuesa, Pablo; Rademaker, Jan L. W.; de Bruijn, Frans J.; Werner, Dietrich

    1998-01-01

    We present a phylogenetic analysis of nine strains of symbiotic nitrogen-fixing bacteria isolated from nodules of tagasaste (Chamaecytisus proliferus) and other endemic woody legumes of the Canary Islands, Spain. These and several reference strains were characterized genotypically at different levels of taxonomic resolution by computer-assisted analysis of 16S ribosomal DNA (rDNA) PCR-restriction fragment length polymorphisms (PCR-RFLPs), 16S-23S rDNA intergenic spacer (IGS) RFLPs, and repetitive extragenic palindromic PCR (rep-PCR) genomic fingerprints with BOX, ERIC, and REP primers. Cluster analysis of 16S rDNA restriction patterns with four tetrameric endonucleases grouped the Canarian isolates with the two reference strains, Bradyrhizobium japonicum USDA 110spc4 and Bradyrhizobium sp. strain (Centrosema) CIAT 3101, resolving three genotypes within these bradyrhizobia. In the analysis of IGS RFLPs with three enzymes, six groups were found, whereas rep-PCR fingerprinting revealed an even greater genotypic diversity, with only two of the Canarian strains having similar fingerprints. Furthermore, we show that IGS RFLPs and even very dissimilar rep-PCR fingerprints can be clustered into phylogenetically sound groupings by combining them with 16S rDNA RFLPs in computer-assisted cluster analysis of electrophoretic patterns. The DNA sequence analysis of a highly variable 264-bp segment of the 16S rRNA genes of these strains was found to be consistent with the fingerprint-based classification. Three different DNA sequences were obtained, one of which was not previously described, and all belonged to the B. japonicum/Rhodopseudomonas rDNA cluster. Nodulation assays revealed that none of the Canarian isolates nodulated Glycine max or Leucaena leucocephala, but all nodulated Acacia pendula, C. proliferus, Macroptilium atropurpureum, and Vigna unguiculata. PMID:9603820

  10. Mechanical test for fuel assembly spacer grid

    International Nuclear Information System (INIS)

    Kang, Heung Seok; Jeong, Yeon Ho; Song, Kee Nam; Kim, Hyung Kyu; Yoon, Kyung Ho; Bang, Je Keun.

    1997-06-01

    In order to propose some tests for a new spacer grid, the grid mechanical tests performed by ABB-CE, KWU and Westinghouse have been investigated. It is known that a static compression test, a dynamic impact test, and a grid spring characteristic test were commonly carried out by the vendors when a prototype spacer grid was developed. The static compression test is to measure the stresses on the strips as well as to obtain the grid stiffness. The dynamic impact test is to get some basic data for accident analysis such as impact stiffness, impact strength, and coefficient of restitution. Since each fuel vendor has his theory on an accident analysis, every vendor employs his particular method for the dynamic impact test. The dynamic impact test can be divided into two in accordance with the number of impact face, and the duration of impact pulse. One is an one-sided impact test and the other is an through-gird impact test. The duration of the impact pulse for the former is considerably shorter than the latter. Therefore, the grid can endure much higher load under the one-sided impact condition than under the through-grid impact condition. The grid spring characteristic test is to obtain a force versus deflection curve. This curve is very important in designing the spacer grid to provide fuel rods with a sound supports in core. (author). 18 tabs., 26 figs

  11. Experimental investigations of turbulent flows in rod bundles with and without spacer grids

    International Nuclear Information System (INIS)

    Trippe, G.

    1979-07-01

    In the thermofluiddynamic design of liquid metal cooled reactor fuel elements the lack of experimentally confirmed knowledge of the three-dimensional flow events in rod bundles provided with spacer grids has appeared as a significant problem. To close this gap of knowledge, detailed measurements of the local velocities were made on a 19-rod bundle model. The Pitot method of differential pressure measurements was used as the measuring system. In the first part of the work the fully developed flow regime not influenced by spacers was investigated. A simple relation was derived for distributing the mass flow among the subchannels of a rod bundle; it is but slightly dependent on the Reynolds number. This relation allows a quick, coarse calculation of the distribution of the undisturbed, fully developed mass flow in bundles with similar geometries. By evaluation of further experiments known from the literature, empirical relationships were found for the local velocity distribution within the subchannels of such bundles. In the second part the effect of grid shaped spacers was investigated. The three-dimensional flow events caused by the spacers were completely recorded and interpreted physically. The deeper understanding of these flow processes can now serve to improve the model concept used in the present design computer programs. Single results of the investigations which take primary importance are the quantitative relations existing between the changes of mass flow in the bundle boundary zone, caused by a spacer, and the geometry of this spacer. The transferability to other bundle geometries was discussed and delimited. Moreover, it was shown that the mass flow in the bundle boundary zone can be successively reduced by spacers placed one behind the other in the bundle. A noticeable dependence of flow events on the Reynolds number was not found for the range relevant in practical application (30.000 [de

  12. Metagenomic data of fungal internal transcribed spacer from serofluid dish, a traditional Chinese fermented food

    Directory of Open Access Journals (Sweden)

    Peng Chen

    2016-03-01

    Full Text Available Serofluid dish (or Jiangshui, in Chinese, a traditional food in the Chinese culture for thousands of years, is made from vegetables by fermentation. In this work, microorganism community of the fermented serofluid dish was investigated by the culture-independent method. The metagenomic data in this article contains the sequences of fungal internal transcribed spacer (ITS regions of rRNA genes from 12 different serofluid dish samples. The metagenome comprised of 50,865 average raw reads with an average of 8,958,220 bp and G + C content is 45.62%. This is the first report on metagenomic data of fungal ITS from serofluid dish employing Illumina platform to profile the fungal communities of this little known fermented food from Gansu Province, China. The Metagenomic data of fungal internal transcribed spacer can be accessed at NCBI, SRA database accession no. SRP067411. Keywords: Serofluid dish, Jiangshui, Fungal ITS, Cultivation-independent, Microbial diversity

  13. Technology of electron beam welding for Zr-4 alloy spacer grid

    International Nuclear Information System (INIS)

    Pei Qiusheng; Wu Xueyi; Yang Qishun

    1989-10-01

    The welding technology for Zr-4 alloy spacer grid by using vacuum electron beam was studied. Through a series of welding technological experiments, metallographic examinations of seam structure and detecting tests for welding defect by X-ray defectoscopy, a good welding technology was selected to meet the requirements. The experimental results indicated that the Zr-4 alloy spacer grid welded by vacuum electron beam welding is feasible

  14. Evaluation of spacer grid spring characteristics by means of physical tests and numerical simulation

    Energy Technology Data Exchange (ETDEWEB)

    Schettino, Carlos Frederico Mattos, E-mail: carlosschettino@inb.gov.br [Industrias Nucleares do Brasil (INB), Resende, RJ (Brazil)

    2017-11-01

    Among all fuel assemblies' components, the spacer grids play an important structural role during the energy generation process, mainly due for its primary functional requirement, that is, to provide fuel rod support. The present work aims to evaluate the spring characteristics of a specific spacer grid design used in a PWR fuel assembly type 16 x 16. These spring characteristics comprises the load versus deflection capability and its spring rate, which are very important, and also mandatory, to be correctly established in order to preclude spacer grid spring and fuel rod cladding fretting during operation, as well as prevent an excessive fuel rod buckling. This study includes physical tests and numerical simulation. The tests were performed on an adapted load cell mechanical device, using as a specimen a single strap of the spacer grid. Three numerical models were prepared using the Finite Element Method, with the support of the commercial code ANSYS. One model was built to validate the simulation according to the performed physical test, the others were built inserting a gradient of temperature (Beginning Of Life hot condition) and to evaluate the spacer grid spring characteristics in End Of Life condition. The obtained results from physical test and numerical model have shown a good agreement between them, therefore validating the simulation. The obtained results from numerical models make available information regarding the spacer grid design purpose, such as the behavior of the fuel rod cladding support during operation. Therewith, these evaluations could be useful to improve the spacer grid design. (author)

  15. Evaluation of spacer grid spring characteristics by means of physical tests and numerical simulation

    International Nuclear Information System (INIS)

    Schettino, Carlos Frederico Mattos

    2017-01-01

    Among all fuel assemblies' components, the spacer grids play an important structural role during the energy generation process, mainly due for its primary functional requirement, that is, to provide fuel rod support. The present work aims to evaluate the spring characteristics of a specific spacer grid design used in a PWR fuel assembly type 16 x 16. These spring characteristics comprises the load versus deflection capability and its spring rate, which are very important, and also mandatory, to be correctly established in order to preclude spacer grid spring and fuel rod cladding fretting during operation, as well as prevent an excessive fuel rod buckling. This study includes physical tests and numerical simulation. The tests were performed on an adapted load cell mechanical device, using as a specimen a single strap of the spacer grid. Three numerical models were prepared using the Finite Element Method, with the support of the commercial code ANSYS. One model was built to validate the simulation according to the performed physical test, the others were built inserting a gradient of temperature (Beginning Of Life hot condition) and to evaluate the spacer grid spring characteristics in End Of Life condition. The obtained results from physical test and numerical model have shown a good agreement between them, therefore validating the simulation. The obtained results from numerical models make available information regarding the spacer grid design purpose, such as the behavior of the fuel rod cladding support during operation. Therewith, these evaluations could be useful to improve the spacer grid design. (author)

  16. In vitro performance of three combinations of spacers and pressurized metered dose inhalers for treatment in children

    DEFF Research Database (Denmark)

    Berg, E; Madsen, J; Bisgaard, H

    1998-01-01

    The performance of pressurized metered dose inhalers (pMDIs) and spacers in correct dose recommendations is important, but limited information on dose delivery and fine-particle dose from different combinations of spacers and pMDIs is available. In this study, three combinations of spacers and p...... and spacers, with the NebuChamber giving the highest dose, both as delivered dose and in droplets account for these differences....

  17. A simulation methodology of spacer grid residual spring deflection for predictive and interpretative purposes

    International Nuclear Information System (INIS)

    Kim, K. T.; Kim, H. K.; Yoon, K. H.

    1994-01-01

    The in-reactor fuel rod support conditions against the fretting wear-induced damage can be evaluated by spacer grid residual spring deflection. In order to predict the spacer grid residual spring deflection as a function of burnup for various spring designs, a simulation methodology of spacer grid residual spring deflection has been developed and implemented in the GRIDFORCE program. The simulation methodology takes into account cladding creep rate, initial spring deflection, initial spring force, and spring force relaxation rate as the key parameters affecting the residual spring deflection. The simulation methodology developed in this study can be utilized as an effective tool in evaluating the capability of a newly designed spacer grid spring to prevent the fretting wear-induced damage

  18. Non linear fe analysis on the static buckling behavior of the spacer grid structures

    International Nuclear Information System (INIS)

    Song, K.N.; Yoon, K.H.

    2001-01-01

    In this study considered is the static buckling behavior of spacer grids in the fuel assembly, which are required to have a sufficient strength against an accident like earthquake. Special attention is given to the finite element modeling of the spot-welding and the constraints between the spacer strips assembled together: it is found that a proper treatment of the constraints is critical for accurate assessment of the buckling behavior including strain localization at the point of spot welding. The buckling strength of the 17 x 17 spacer grid, which is difficult to analyze due to a large number of degrees of freedom, is estimated from analysis for the smaller models 3 x 3, 5 x 5, 7 x 7, and 9 x 9 spacer grids. (authors)

  19. Molecular evidence confirms the taxonomic separation of Lutzomyia tihuiliensis from Lutzomyia pia (Diptera: Psychodidae) and the usefulness of pleural pigmentation patterns in species identification.

    Science.gov (United States)

    Pérez-Doria, Alveiro; Bejarano, Eduar Elías; Sierra, Diana; Vélez, Iván Darío

    2008-07-01

    The phlebotomine sand flies Lutzomyia pia (Fairchild & Hertig 1961) and Lutzomyia tihuiliensis Le Pont, Torrez-Espejo & Dujardin 1997 (Diptera: Psychodidae) belong to the pia series of the Lu. verrucarum species group, which includes several species that bite humans in Andean foci of leishmaniasis. The females of these two species exhibit isometry and isomorphism in anatomical structures of the head and terminalia commonly used in taxonomic identification of sand flies. They can only be differentiated based on subtle differences in the pigmentation of the pleura. In Lu. tihuiliensis, this is restricted to the basal portions of the katepimeron and katepisternum, whereas in Lu. pia both structures are totally pigmented. Taking into account the subtle morphological differences between these species, the objective of the current study was to evaluate the specific taxonomic status of Lu. tihuiliensis with respect to Lu. pia. A 475-bp portion of the mitochondrial genome was sequenced, composed of the 3' end of the cytochrome b gene, intergenic spacer 1, the transfer RNA gene for serine, intergenic spacer 2, and the 3' end of the gene NAD dehydrogenase 1. Genetic analysis confirms that Lu. tihuiliensis and Lu. pia constitute two distinct species and this is supported by four strong lines of evidence, i.e., the paired genetic distances, size differences and amino acid composition of the cytochrome b protein, presence and absence of intergenic spacer one and divergence observed in the sequence of the transfer RNA gene for serine. It also confirms the validity of the pleural pigmentation pattern as a species diagnostic character and the importance of performing a detailed examination of this character during morphological determination of phlebotomine sand flies in the series pia.

  20. Nuclear reactor spring strip grid spacer

    International Nuclear Information System (INIS)

    Patterson, J.F.; Flora, B.S.

    1978-01-01

    A bimetallic grid spacer is described comprising a grid structure of zircaloy formed by intersecting striplike members which define fuel element openings for receiving fuel elements and spring strips made of Inconel positioned within the grid structure for cooperating with the fuel elements to maintain them in their desired position. A plurality of these spring strips extend longitudinally between sides of the grid structure, being locked in position by the grid retaining strips. The fuel rods, which are disposed in the fuel openings formed in the grid structure, are positioned by means of the springs associated with the spring strips and a plurality of dimples which extend from the zircaloy grid structure into the openings. In one embodiment the strips are disposed in a plurality of arrays with those spring strip arrays situated in opposing diagonal quadrants of the grid structure extending in the same direction and adjacent spring strip arrays in each half of the spacer extending in relatively perpendicular directions. Other variations of the spring strip arrangements for a particular fuel design are disclosed herein

  1. A study on the characteristics of the spacer spring by finite element method

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sung Keun; Kim, Hyung Kyu; Kim, Kyu Tae [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1995-06-01

    The mechanical integrity of spacer springs in KOFA was certified through the mechanical tests by KWU. In this report, the spacer spring characteristics were obtained by using a commercial FEM code ANSYS, and the calculated results were compared with the mechanical test results. It has been found that the analytical results from ANSYS were in good agreement with the test results in the actual working range of the spacer springs even though some errors occurred in the range of initial spring deflection. The errors were thought to occur due to the simplified boundary conditions and the nominal dimensions which are used in calculations rather than the as-fabricated dimensions. Though the results from ANSYS are not fully satisfied, the analytical method in this report has been verified to be used as a method for investigating the characteristic of spacer springs roughly before conducting mechanical tests. 8 tabs., 25 figs (Author) .new.

  2. Saprolegniaceae identified on amphibian eggs throughout the Pacific Northwest, USA, by internal transcribed spacer sequences and phylogenetic analysis

    Science.gov (United States)

    Jill E. Petrisko; Christopher A. Pearl; David S. Pilliod; Peter P. Sheridan; Charles F. Williams; Charles R. Peterson; R. Bruce Bury

    2008-01-01

    We assessed the diversity and phylogeny of Saprolegniaceae on amphibian eggs from the Pacific Northwest, with particular focus on Saprolegnia ferax, a species implicated in high egg mortality. We identified isolates from eggs of six amphibians with the internal transcribed spacer (ITS) and 5.8S gene regions and BLAST of the GenBank database. We...

  3. A culture-based survey of fungi in soil from bat hibernacula in the eastern United States and its implications for detection of Geomyces destructans, the causal agent of bat white-nose syndrome

    Science.gov (United States)

    Lorch, Jeffrey M.; Lindner, Daniel L.; Gargas, Andrea; Muller, Laura K.; Minnis, Andrew M.; Blehert, David S.

    2013-01-01

    The recent emergence of white-nose syndrome (WNS), a fungal disease causing unprecedented mortality among hibernating bats of eastern North America, has revealed a knowledge gap regarding fungal communities associated with bats and their hibernacula. We used culture-based techniques to investigate the diversity of fungi in soil samples collected from 24 bat hibernacula in the eastern United States. Ribosomal RNA regions (internal transcribed spacer and partial intergenic spacer) were sequenced to preliminarily characterize isolates. Geomyces species were one of the most abundant and diverse groups cultured, representing approximately 33% of all isolates. Geomyces destructans was isolated from soil samples from three hibernacula in states where WNS is known to occur, and many of the other cultured Geomyces isolates likely represent undescribed taxa. Further characterization of the diversity of fungi that occur in hibernacula will both facilitate an improved understanding of the ecology of G. destructans within this complex fungal community and provide an opportunity to identify characteristics that differentiate G. destructans from non-pathogenic relatives.

  4. Phylogenetic study of Geitlerinema and Microcystis (Cyanobacteria) using PC-IGS and 16S-23S ITS as markers: investigation of horizontal gene transfer.

    Science.gov (United States)

    Piccin-Santos, Viviane; Brandão, Marcelo Mendes; Bittencourt-Oliveira, Maria Do Carmo

    2014-08-01

    Selection of genes that have not been horizontally transferred for prokaryote phylogenetic inferences is regarded as a challenging task. The markers internal transcribed spacer of ribosomal genes (16S-23S ITS) and phycocyanin intergenic spacer (PC-IGS), based on the operons of ribosomal and phycocyanin genes respectively, are among the most used markers in cyanobacteria. The region of the ribosomal genes has been considered stable, whereas the phycocyanin operon may have undergone horizontal transfer. To investigate the occurrence of horizontal transfer of PC-IGS, phylogenetic trees of Geitlerinema and Microcystis strains were generated using PC-IGS and 16S-23S ITS and compared. Phylogenetic trees based on the two markers were mostly congruent for Geitlerinema and Microcystis, indicating a common evolutionary history among ribosomal and phycocyanin genes with no evidence for horizontal transfer of PC-IGS. Thus, PC-IGS is a suitable marker, along with 16S-23S ITS for phylogenetic studies of cyanobacteria. © 2014 Phycological Society of America.

  5. Fleas and Flea-Associated Bartonella Species in Dogs and Cats from Peru.

    Science.gov (United States)

    Rizzo, M F; Billeter, S A; Osikowicz, L; Luna-Caipo, D V; Cáceres, A G; Kosoy, M

    2015-11-01

    In the present study, we investigated 238 fleas collected from cats and dogs in three regions of Peru (Ancash, Cajamarca, and Lima) for the presence of Bartonella DNA. Bartonella spp. were detected by amplification of the citrate synthase gene (16.4%) and the 16S-23S intergenic spacer region (20.6%). Bartonella rochalimae was the most common species detected followed by Bartonella clarridgeiae and Bartonella henselae. Our results demonstrate that dogs and cats in Peru are infested with fleas harboring zoonotic Bartonella spp. and these infected fleas could pose a disease risk for humans. Published by Oxford University Press on behalf of Entomological Society of America 2015. This work is written by US Government employees and is in the public domain in the US.

  6. Nuclear reactor spring strip grid spacer

    International Nuclear Information System (INIS)

    Patterson, J.F.; Flora, B.S.

    1980-01-01

    An improved and novel grid spacer for maintaining the fuel rods of a nuclear reactor fuel assembly in substantially parallel array is described. The invention provides for spring strips to maintain the fuel elements in their desired orientation which have more positive alignment than previous types while allowing greater flexibility to counterbalance the effects of differential thermal expansion. (UK)

  7. Genome-wide CpG island methylation and intergenic demethylation propensities vary among different tumor sites.

    Science.gov (United States)

    Lee, Seung-Tae; Wiemels, Joseph L

    2016-02-18

    The epigenetic landscape of cancer includes both focal hypermethylation and broader hypomethylation in a genome-wide manner. By means of a comprehensive genomic analysis on 6637 tissues of 21 tumor types, we here show that the degrees of overall methylation in CpG island (CGI) and demethylation in intergenic regions, defined as 'backbone', largely vary among different tumors. Depending on tumor type, both CGI methylation and backbone demethylation are often associated with clinical, epidemiological and biological features such as age, sex, smoking history, anatomic location, histological type and grade, stage, molecular subtype and biological pathways. We found connections between CGI methylation and hypermutability, microsatellite instability, IDH1 mutation, 19p gain and polycomb features, and backbone demethylation with chromosomal instability, NSD1 and TP53 mutations, 5q and 19p loss and long repressive domains. These broad epigenetic patterns add a new dimension to our understanding of tumor biology and its clinical implications. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  8. Predicting the impact of feed spacer modification on biofouling by hydraulic characterization and biofouling studies in membrane fouling simulators

    KAUST Repository

    Siddiqui, Amber

    2016-12-22

    Feed spacers are an essential part of spiral-wound reverse osmosis (RO) and nanofiltration (NF) membrane modules. Geometric modification of feed spacers is a potential option to reduce the impact of biofouling on the performance of membrane systems. The objective of this study was to evaluate the biofouling potential of two commercially available reference feed spacers and four modified feed spacers. The spacers were compared on hydraulic characterization and in biofouling studies with membrane fouling simulators (MFSs). The virgin feed spacer was characterized hydraulically by their resistance, measured in terms of feed channel pressure drop, performed by operating MFSs at varying feed water flow rates. Short-term (9 days) biofouling studies were carried out with nutrient dosage to the MFS feed water to accelerate the biofouling rate. Long-term (96 days) biofouling studies were done without nutrient dosage to the MFS feed water. Feed channel pressure drop was monitored and accumulation of active biomass was quantified by adenosine tri phosphate (ATP) determination. The six feed spacers were ranked on pressure drop (hydraulic characterization) and on biofouling impact (biofouling studies). Significantly different trends in hydraulic resistance and biofouling impact for the six feed spacers were observed. The same ranking for biofouling impact on the feed spacers was found for the (i) short-term biofouling study with nutrient dosage and the (ii) long-term biofouling study without nutrient dosage. The ranking for hydraulic resistance for six virgin feed spacers differed significantly from the ranking of the biofouling impact, indicating that hydraulic resistance of clean feed spacers does not predict the hydraulic resistance of biofouled feed spacers. Better geometric design of feed spacers can be a suitable approach to minimize impact of biofouling in spiral wound membrane systems.

  9. On the Origin of Reverse Transcriptase-Using CRISPR-Cas Systems and Their Hyperdiverse, Enigmatic Spacer Repertoires

    Directory of Open Access Journals (Sweden)

    Sukrit Silas

    2017-07-01

    Full Text Available Cas1 integrase is the key enzyme of the clustered regularly interspaced short palindromic repeat (CRISPR-Cas adaptation module that mediates acquisition of spacers derived from foreign DNA by CRISPR arrays. In diverse bacteria, the cas1 gene is fused (or adjacent to a gene encoding a reverse transcriptase (RT related to group II intron RTs. An RT-Cas1 fusion protein has been recently shown to enable acquisition of CRISPR spacers from RNA. Phylogenetic analysis of the CRISPR-associated RTs demonstrates monophyly of the RT-Cas1 fusion, and coevolution of the RT and Cas1 domains. Nearly all such RTs are present within type III CRISPR-Cas loci, but their phylogeny does not parallel the CRISPR-Cas type classification, indicating that RT-Cas1 is an autonomous functional module that is disseminated by horizontal gene transfer and can function with diverse type III systems. To compare the sequence pools sampled by RT-Cas1-associated and RT-lacking CRISPR-Cas systems, we obtained samples of a commercially grown cyanobacterium—Arthrospira platensis. Sequencing of the CRISPR arrays uncovered a highly diverse population of spacers. Spacer diversity was particularly striking for the RT-Cas1-containing type III-B system, where no saturation was evident even with millions of sequences analyzed. In contrast, analysis of the RT-lacking type III-D system yielded a highly diverse pool but reached a point where fewer novel spacers were recovered as sequencing depth was increased. Matches could be identified for a small fraction of the non-RT-Cas1-associated spacers, and for only a single RT-Cas1-associated spacer. Thus, the principal source(s of the spacers, particularly the hypervariable spacer repertoire of the RT-associated arrays, remains unknown.

  10. Chromosome and genome size variation in Luzula (Juncaceae), a genus with holocentric chromosomes

    Czech Academy of Sciences Publication Activity Database

    Bozek, M.; Leitch, A. R.; Leitch, I. J.; Záveská Drábková, Lenka; Kuta, E.

    2012-01-01

    Roč. 170, č. 4 (2012), s. 529-541 ISSN 0024-4074 R&D Projects: GA ČR GP206/07/P147 Institutional support: RVO:67985939 Keywords : chromosomal evolution * endopolyploidy * holokinetic chromosome * karyotype evolution * tetraploides * centromeres * TRNF intergenic spacer Subject RIV: EF - Botanics Impact factor: 2.589, year: 2012

  11. USE OF ANTIBIOTIC CEMENT SPACERS/BEADS IN TREATMENT ...

    African Journals Online (AJOL)

    ABSTRACT. Background: Chronic musculoskeletal infection involving bone present a big challenge to orthopaedic surgeons. ... Current data has demonstrated that the use of .... Antibiotic spacers are effective and add value in the treament of ...

  12. Ion therapy of prostate cancer: daily rectal dose reduction by application of spacer gel

    International Nuclear Information System (INIS)

    Rucinski, Antoni; Brons, Stephan; Richter, Daniel; Habl, Gregor; Debus, Jürgen; Bert, Christoph; Haberer, Thomas; Jäkel, Oliver

    2015-01-01

    Ion beam therapy represents a promising approach to treat prostate cancer, mainly due to its high conformity and radiobiological effectiveness. However, the presence of prostate motion, patient positioning and range uncertainties may deteriorate target dose and increase exposure of organs at risk. Spacer gel injected between prostate and rectum may increase the safety of prostate cancer (PC) radiation therapy by separating the rectum from the target dose field. The dosimetric impact of the application of spacer gel for scanned carbon ion therapy of PC has been analyzed at Heidelberg Ion-Beam Therapy Center (HIT). The robustness of ion therapy treatment plans was investigated by comparison of two data sets of patients treated with and without spacer gel. A research treatment planning system for ion therapy was used for treatment plan optimization and calculation of daily dose distributions on 2 to 9 Computed Tomography (CT) studies available for each of the 19 patients. Planning and daily dose distributions were analyzed with respect to target coverage, maximal dose to the rectum (excluding 1 ml of the greatest dose; Dmax-1 ml) and the rectal volume receiving dose greater than 90% of prescribed target dose (V90 Rectum ), respectively. The application of spacer gel did substantially diminish rectum dose. Dmax-1 ml on the treatment planning CT was on average reduced from 100.0 ± 1.0% to 90.2 ± 4.8%, when spacer gel was applied. The robustness analysis performed with daily CT studies demonstrated for all analyzed patient cases that application of spacer gel results in a decrease of the daily V90 Rectum index, which calculated over all patient cases and CT studies was 10.2 ± 10.4 [ml] and 1.1 ± 2.1 [ml] for patients without and with spacer gel, respectively. The dosimetric benefit of increasing the distance between prostate and rectum using spacer gel for PC treatment with carbon ion beams has been quantified. Application of spacer gel substantially reduced rectal

  13. Restrição do 16S-23S DNAr intergênico para avaliação da diversidade de Azospirillum amazonense isolado de Brachiaria spp. Restriction of 16S-23S intergenic rDNA for diversity evaluation of Azospirillum amazonense isolated from different Brachiaria spp.

    Directory of Open Access Journals (Sweden)

    Fábio Bueno dos Reis Junior

    2006-03-01

    Full Text Available O objetivo deste trabalho foi avaliar a diversidade intra-específica de isolados de Azospirillum amazonense e estabelecer a possível influência de diferentes espécies de Brachiaria ssp. e diferentes condições edafoclimáticas. A caracterização da diversidade desses isolados foi conduzida, utilizando-se a análise de restrição da região intergênica 16S-23S DNAr. As estirpes estudadas separaram-se em dois grupos, definidos a 56% de similaridade. As espécies de Brachiaria ssp. influenciaram a diversidade de estirpes. A maioria dos isolados oriundos de B. decumbens e B. brizantha está inserida no primeiro grupo, enquanto os oriundos de B. humidicola concentram-se no segundo grupo.The aim of this work was to study the intra-specific diversity of Azospirillum amazonense isolates and to establish possible influences of different Brachiaria spp. and edaphoclimatic conditions. The characterization of the diversity among the isolates of A. amazonense studied was conducted using restriction analysis of the 16S-23S rDNA intergenic spacer region. The evaluated strains were separated in two groups, defined at 56% of similarity. Brachiaria spp. showed effects on strain diversity. Most part of the isolates from B. decumbens and B. brizantha are inserted in the first group, while B. humidicola isolates concentrate in the second group.

  14. The effect of endoskeleton on antibiotic impregnated cement spacer for treating deep hip infection

    Directory of Open Access Journals (Sweden)

    Hsu Wei-Hsiu

    2011-01-01

    Full Text Available Abstract Backgrounds A two-stage revision arthroplasty was suggested optimal treatment for deep infections in hip joint. The effect of endoskeleton of cement spacers on the interim function and infection control remains unclear. Methods From Jan. 2004 to Dec. 2007, we collected a prospective cohort of consecutive 34 patients who treated with two-stage revision total hip arthroplasty for deep infection of hip joint. In group 1, fifteen patients were treated by a novel design augmented with hip compression screw while nineteen patients were treated by traditional design in group 2. Results No fracture of cement spacer occurred in group 1 while 6 cases developed spacer failure in group 2. (p Conclusions Patients being treated for deep infection of hip joint using cement spacer augmented with stronger endoskeleton have lower pain levels and better joint function between stages.

  15. Development and characterization of 3D-printed feed spacers for spiral wound membrane systems

    KAUST Repository

    Siddiqui, Amber; Farhat, Nadia; Bucs, Szilard; Valladares Linares, Rodrigo; Picioreanu, Cristian; Kruithof, Joop C.; van Loosdrecht, Mark C.M.; Kidwell, James; Vrouwenvelder, Johannes S.

    2016-01-01

    suggested that the impact of spacers on hydraulics and biofouling can be improved. A good agreement was found for the modeled and measured relationship between linear flow velocity and pressure drop for feed spacers with the same geometry, indicating

  16. Molecular Identification of Isolated Fungi from Unopened Containers of Greek Yogurt by DNA Sequencing of Internal Transcribed Spacer Region

    Directory of Open Access Journals (Sweden)

    Irshad M. Sulaiman

    2014-06-01

    Full Text Available In our previous study, we described the development of an internal transcribed spacer (ITS1 sequencing method, and used this protocol in species-identification of isolated fungi collected from the manufacturing areas of a compounding company known to have caused the multistate fungal meningitis outbreak in the United States. In this follow-up study, we have analyzed the unopened vials of Greek yogurt from the recalled batch to determine the possible cause of microbial contamination in the product. A total of 15 unopened vials of Greek yogurt belonging to the recalled batch were examined for the detection of fungi in these samples known to cause foodborne illness following conventional microbiological protocols. Fungi were isolated from all of the 15 Greek yogurt samples analyzed. The isolated fungi were genetically typed by DNA sequencing of PCR-amplified ITS1 region of rRNA gene. Analysis of data confirmed all of the isolated fungal isolates from the Greek yogurt to be Rhizomucor variabilis. The generated ITS1 sequences matched 100% with the published sequences available in GenBank. In addition, these yogurt samples were also tested for the presence of five types of bacteria (Salmonella, Listeria, Staphylococcus, Bacillus and Escherichia coli causing foodborne disease in humans, and found negative for all of them.

  17. c-Abl phosphorylation of Yin Yang 1's conserved tyrosine 254 in the spacer region modulates its transcriptional activity.

    Science.gov (United States)

    Daraiseh, Susan I; Kassardjian, Ari; Alexander, Karen E; Rizkallah, Raed; Hurt, Myra M

    2018-05-25

    Yin Yang 1 (YY1) is a multifunctional transcription factor that can activate or repress transcription depending on the promotor and/or the co-factors recruited. YY1 is phosphorylated in various signaling pathways and is critical for different biological functions including embryogenesis, apoptosis, proliferation, cell-cycle regulation and tumorigenesis. Here we report that YY1 is a substrate for c-Abl kinase phosphorylation at conserved residue Y254 in the spacer region. Pharmacological inhibition of c-Abl kinase by imatinib, nilotinib and GZD824, knock-down of c-Abl using siRNA, and the use of c-Abl kinase-dead drastically reduces tyrosine phosphorylation of YY1. Both radioactive and non-radioactive in vitro kinase assays, as well as co-immunoprecipitation in different cell lines, show that the target of c-Abl phosphorylation is tyrosine residue 254. c-Abl phosphorylation has little effect on YY1 DNA binding ability or cellular localization in asynchronous cells. However, functional studies reveal that c-Abl mediated phosphorylation of YY1 regulates YY1's transcriptional ability in vivo. In conclusion, we demonstrate the novel role of c-Abl kinase in regulation of YY1's transcriptional activity, linking YY1 regulation with c-Abl tyrosine kinase signaling pathways. Copyright © 2018. Published by Elsevier B.V.

  18. Biofouling Control in Spiral-Wound Membrane Systems: Impact of Feed Spacer Modification and Biocides

    KAUST Repository

    Siddiqui, Amber

    2016-01-01

    was developed. The combination of modeling and experimental testing of 3D printed spacers is a promising strategy to develop advanced spacers aiming to reduce the impact of biofilm formation on membrane performance and to improve the cleanability of spiral

  19. Simulation study of transfer characteristics for spacer-filled membrane distillation desalination modules

    International Nuclear Information System (INIS)

    Chang, Hsuan; Hsu, Jian-An; Chang, Cheng-Liang; Ho, Chii-Dong; Cheng, Tung-Wen

    2017-01-01

    Highlights: • A 3D CFD model takes in transmembrane heat and mass transfer developed. • DCMD modules using spacer-filled and empty channels for desalination simulated. • Fluid flow, heat transfer and mass transfer profiles revealed. • Correlations of friction factor and Nusselt number developed. - Abstract: Membrane distillation (MD) is an emerging and promising membrane separation process, which can directly utilize renewable thermal energy or low-grade waste heat, for applications in water or wastewater treatment and food industry. However, a major drawback of MD process is its low energy efficiency. Spacer is the most suggested and studied eddy promoter to enhance the heat and mass transfer, which further improves both the separation and the energy utilization performance, of MD processes. This paper presents the results of a 3D computational fluid dynamics (CFD) simulation of DCMD (direct contact membrane distillation) modules using channels with and without spacers for desalination application. The model employs permeable wall boundary condition to take into account the transmembrane heat and mass transfer and simulates the entire module length. The simulation reveals similar fluctuating distributions of temperature polarization coefficient, transmembrane heat and mass fluxes as well as the shear stress on the membrane surface along the entire module length. Correlations have been developed for friction factor and average Nusselt number. These correlations are useful for the analysis and design of DCMD modules. The extent of heat transfer enhancement by spacers depends on the geometry of spacers and the Reynolds number of fluid.

  20. The cyanobiont in an Azolla fern is neither Anabaena nor Nostoc.

    Science.gov (United States)

    Baker, Judith A; Entsch, Barrie; McKay, David B

    2003-12-05

    The cyanobacterial symbionts in the fern Azolla have generally been ascribed to either the Anabaena or Nostoc genera. By using comparisons of the sequences of the phycocyanin intergenic spacer and a fragment of the 16S rRNA, we found that the cyanobiont from an Azolla belongs to neither of these genera.

  1. Microbiologic Evaluation of Cotton and Polytetrafluoroethylene (PTFE) Tape as Endodontic Spacer Materials in Primary Molars An in Vivo Study.

    Science.gov (United States)

    Prabhakar, Attiguppe Ramasetty; Dixit, Kratika; Raju, O S

    PTFE tape, which is commonly used as plumber's tape is an inorganic, non-fibrous, ribbon like material. The aim of this study was to evaluate PTFE tape as endodontic spacer material and to compare it with commonly used spacer material that is cotton, in primary teeth. Seventeen children undergoing pulpectomy of lower second primary molar bilaterally were included in the study. Cotton and PTFE tape were placed as spacers on each side randomly. Samples were taken from the access cavity at baseline and after seven days to check for microbial leakage. Spacer materials were also checked for microbial contamination. The results revealed that there was a significant increase in the bacterial colony count after seven days in cotton group. The access cavities were also positive for microbial leakage in the cotton group where the spacers showed positive growth. In PTFE group only two samples showed microbial contamination of spacer and out of two only one sample showed contamination of access cavity along with spacer. Within the limitations of this study, it can be concluded that PTFE tape performed better than cotton as endodontic spacer material. Thus, PTFE tape can be recommended as an endodontic spacer material as an alternative to cotton in primary teeth.

  2. Spacers for fuel rod clusters

    International Nuclear Information System (INIS)

    Jabsen, F.S.

    1978-01-01

    The proposition deals with the fixing of nuclear fuel element rods in a grid which consists of a number of crossed Zy-plates which form cells. The rectangular cells have projections which serve as spacers for the fuel rods. According to the invention there are additional butt straps which can be moved in such a way that insertion and extraction of the fuel rods can be done without obstruction and they can be spring-loaded hold in their final position. (UWI) [de

  3. Organic light-emitting diodes with a spacer enhanced exciplex emission

    Science.gov (United States)

    Yan, Fei; Chen, Rui; Sun, Handong; Wei Sun, Xiao

    2014-04-01

    By introducing a spacer molecule into the blended exciplex emissive layer, the performance of the bulk heterojunction exciplex organic light-emitting diodes (OLEDs) was improved dramatically; the maximum luminous efficiency was enhanced by about 22% from 7.9 cd/A to 9.7 cd/A, and the luminous efficiency drop was reduced by 28% at 400 mA/cm2. Besides the suppressed annihilation of exciton, the time-resolved photoluminescence measurements indicated that the spacer enhanced the delayed fluorescence through increasing the backward intersystem crossing rate from the triplet to singlet exciplex state. This method is useful for developing high performance exciplex OLEDs.

  4. Functional Characterization of MC1R-TUBB3 Intergenic Splice Variants of the Human Melanocortin 1 Receptor.

    Directory of Open Access Journals (Sweden)

    Cecilia Herraiz

    Full Text Available The melanocortin 1 receptor gene (MC1R expressed in melanocytes is a major determinant of skin pigmentation. It encodes a Gs protein-coupled receptor activated by α-melanocyte stimulating hormone (αMSH. Human MC1R has an inefficient poly(A site allowing intergenic splicing with its downstream neighbour Tubulin-β-III (TUBB3. Intergenic splicing produces two MC1R isoforms, designated Iso1 and Iso2, bearing the complete seven transmembrane helices from MC1R fused to TUBB3-derived C-terminal extensions, in-frame for Iso1 and out-of-frame for Iso2. It has been reported that exposure to ultraviolet radiation (UVR might promote an isoform switch from canonical MC1R (MC1R-001 to the MC1R-TUBB3 chimeras, which might lead to novel phenotypes required for tanning. We expressed the Flag epitope-tagged intergenic isoforms in heterologous HEK293T cells and human melanoma cells, for functional characterization. Iso1 was expressed with the expected size. Iso2 yielded a doublet of Mr significantly lower than predicted, and impaired intracellular stability. Although Iso1- and Iso2 bound radiolabelled agonist with the same affinity as MC1R-001, their plasma membrane expression was strongly reduced. Decreased surface expression mostly resulted from aberrant forward trafficking, rather than high rates of endocytosis. Functional coupling of both isoforms to cAMP was lower than wild-type, but ERK activation upon binding of αMSH was unimpaired, suggesting imbalanced signaling from the splice variants. Heterodimerization of differentially labelled MC1R-001 with the splicing isoforms analyzed by co-immunoprecipitation was efficient and caused decreased surface expression of binding sites. Thus, UVR-induced MC1R isoforms might contribute to fine-tune the tanning response by modulating MC1R-001 availability and functional parameters.

  5. Mechanical Properties Of 3D-Structure Composites Based On Warp-Knitted Spacer Fabrics

    Directory of Open Access Journals (Sweden)

    Chen Si

    2015-06-01

    Full Text Available In this paper, the mechanical properties (compression and impact behaviours of three-dimension structure (3D-structure composites based on warp-knitted spacer fabrics have been thoroughly investigated. In order to discuss the effect of fabric structural parameters on the mechanical performance of composites, six different types of warp-knitted spacer fabrics having different structural parameters (such as outer layer structure, diameter of spacer yarn, spacer yarn inclination angle and thickness were involved for comparison study. The 3D-structure composites were fabricated based on a flexible polyurethane foam. The produced composites were characterised for compression and impact properties. The findings obtained indicate that the fabric structural parameters have strong influence on the compression and impact responses of 3D-structure composites. Additionally, the impact test carried out on the 3D-structure composites shows that the impact loads do not affect the integrity of composite structure. All the results reveal that the product exhibits promising mechanical performance and its service life can be sustained.

  6. Effect of Weld Properties on the Crush Strength of the PWR Spacer Grid

    Directory of Open Access Journals (Sweden)

    Kee-nam Song

    2012-01-01

    Full Text Available Mechanical properties in a weld zone are different from those in the base material because of different microstructures. A spacer grid in PWR fuel is a structural component with an interconnected and welded array of slotted grid straps. Previous research on the strength analyses of the spacer grid was performed using base material properties owing to a lack of mechanical properties in the weld zone. In this study, based on the mechanical properties in the weld zone of the spacer grid recently obtained by an instrumented indentation technique, the strength analyses considering the mechanical properties in the weld zone were performed, and the analysis results were compared with the previous research.

  7. Barriers and supports to implementation of MDI/spacer use in nine Canadian pediatric emergency departments: a qualitative study

    Directory of Open Access Journals (Sweden)

    Graham Ian D

    2009-10-01

    Full Text Available Abstract Background Despite recent research supporting the use of metered dose inhalers with spacer devices (MDI/spacers in pediatric emergency departments (PEDs for acute exacerbations of asthma, uptake of this practice has been slow. The objectives of this study were to determine the barriers and supports to implementing MDI/spacer research and to identify factors associated with early and late adoption of MDI/spacers in Canadian PEDs. Methods Using a comparative case study design, we classified nine tertiary care pediatric hospital PEDs based on their stage of implementation. Data were collected using focus group interviews with physicians, registered nurses (RNs, and respiratory therapists (RTs, and individual interviews with both patient care and medical directors at each site. Initial coding was based on the Ottawa Model of Research Use (OMRU categories of elements known to influence the uptake of innovations. Results One hundred and fifty healthcare professionals from nine different healthcare institutions participated in this study. Lack of leadership in the form of a research champion, a lack of consensus about the benefits of MDI/spacers among staff, perceived resistance from patients/parents, and perceived increased cost and workload associated with MDI/spacer use were the most prevalent barriers to the adoption of the MDI/spacer. Common strategies used by early-adopting sites included the active participation of all professional groups in the adoption process in addition to a well-planned and executed educational component for staff, patients, and families. Early adopter sites were also more likely to have the MDI/spacer included in a clinical protocol/pathway. Conclusion Potential barriers and supports to implementation have been identified that will help EDs adopt MDI/spacer use. Future interventions intended to increase MDI/spacer use in PEDs will need to be sensitive to the barriers identified in this study.

  8. Prediction of droplet deposition around BWR fuel spacer by FEM flow analysis

    International Nuclear Information System (INIS)

    Yamamoto, Yasushi; Morooka, Shinichi

    1997-01-01

    The critical power of the BWR fuel assembly has been remarkably increased. That increase mainly depends on the improvement of the spacer which keeps fixed gaps between fuel rods. So far, these improvements have been carried out on the basis of what developers consider to be appropriate and the results of mockup tests of the BWR fuel assembly. However, continued reliance on these approaches for the development of a higher performance fuel assembly will prove time-consuming and costly. Therefore, it is hoped that the spacer effects for the critical power can be investigated by computer simulation, and it is significantly important to develop the critical power prediction method. Direct calculation of the two-phase flow in a BWR fuel channel s still difficult. Accordingly, a new method for predicting the critical power was proposed. Our method consists of CFD (computer fluid dynamics) code based on the single-phase flow analysis method and the subchannel analysis code. To verify our method, the critical power predictions for various spacer geometries were performed. The predicted results of the critical power were compared with the experimental data. The result of the comparison showed a good agreement and the applicability of our method for various spacer geometries. (author)

  9. Dancing together and separate again: gymnosperms exhibit frequent changes of fundamental 5S and 35S rRNA gene (rDNA) organisation

    Czech Academy of Sciences Publication Activity Database

    Garcia, S.; Kovařík, Aleš

    2013-01-01

    Roč. 111, č. 1 (2013), s. 23-33 ISSN 0018-067X R&D Projects: GA ČR(CZ) GA13-10057S; GA ČR GBP501/12/G090 Institutional support: RVO:68081707 Keywords : rRNA gene organisation * intergenic spacer * Ginkgo Subject RIV: BO - Biophysics Impact factor: 3.804, year: 2013

  10. High-temperature carrier density and mobility enhancements in AlGaN/GaN HEMT using AlN spacer layer

    Science.gov (United States)

    Ko, Tsung-Shine; Lin, Der-Yuh; Lin, Chia-Feng; Chang, Che-Wei; Zhang, Jin-Cheng; Tu, Shang-Ju

    2017-04-01

    In this paper, we experimentally studied the effect of AlN spacer layer on optical and electrical properties of AlGaN/GaN high electric mobility transistors (HEMTs) grown by metal organic chemical vapor deposition method. For AlGaN layer in HEMT structure, the Al composition of the sample was determined using x-ray diffraction and photoluminescence. Electrolyte electro-reflectance (EER) measurement not only confirmed the aluminum composition of AlGaN layer, but also determined the electric field strength on the AlGaN layer through the Franz-Keldysh oscillation phenomenon. This result indicated that the electric field on the AlGaN layer could be improved from 430 to 621 kV/cm when AlN spacer layer was inserted in HEMT structure, which increased the concentration of two dimensional electron gas (2DEG) and improve the mobility. The temperature dependent Hall results show that both the mobility and the carrier concentration of 2DEG would decrease abruptly causing HEMT loss of function due to phonon scattering and carrier thermal escape when temperature increases above a specific value. Meanwhile, our study also demonstrates using AlN spacer layer could be beneficial to allow the mobility and carrier density of 2DEG sustaining at high temperature region.

  11. In Silico Study of Spacer Arm Length Influence on Drug Vectorization by Fullerene C60

    Directory of Open Access Journals (Sweden)

    Haifa Khemir

    2015-01-01

    Full Text Available This work studies theoretically the effect of spacer arm lengths on the characteristics of a fullerene C60-based nanovector. The spacer arm is constituted of a carbon chain including a variable number of methylene groups (n = 2–11. To improve the ability of the fullerene carriage, two arms are presented simultaneously through a malonyl bridge. Then the evolution of selected physicochemical parameters is monitored as a function of the spacer arm length and the angle between the two arms. We show here that while the studied characteristics are almost independent of the spacer arm length or vary monotonically with it, the dipole moment and its orientation vary periodically with the parity of the number of carbon atoms. This periodicity is related to both modules and orientations of dipole moments of the spacer arms. In the field of chemical synthesis, these results highlight the importance of theoretical calculations for the optimization of operating conditions. In the field of drug discovery, they show that theoretical calculations of the chemical properties of a drug candidate can help predict its in vivo behaviour, notably its bioavailability and biodistribution, which are known to be tightly dependent of its polarity.

  12. A high-performance channel engineered charge-plasma-based MOSFET with high-κ spacer

    Science.gov (United States)

    Shan, Chan; Wang, Ying; Luo, Xin; Bao, Meng-tian; Yu, Cheng-hao; Cao, Fei

    2017-12-01

    In this paper, the performance of graded channel double-gate MOSFET (GC-DGFET) that utilizes the charge-plasma concept and a high-κ spacer is investigated through 2-D device simulations. The results demonstrate that GC-DGFET with high-κ spacer can effectively improve the ON-state driving current (ION) and reduce the OFF-leakage current (IOFF). We find that reduction of the initial energy barrier between the source and channel is the origin of this ION enhancement. The reason for the IOFF reduction is identified to be the extension of the effective channel length owing to the fringing field via high-κ spacers. Consequently, these devices offer enhanced performance by reducing the total gate-to-gate capacitance (Cgg) and decreasing the intrinsic delay (τ).

  13. Geometric effects of spacer grid in an annulus flow channel during reflooding period

    International Nuclear Information System (INIS)

    Cho, S.; Chun, S. Y.; Kim, B. D.; Park, J. K.; Yun, Y. J.; Baek, W. P.

    2004-01-01

    A number of studies on the reflooding phase were actively carried out from the early 70's due to its importance for the safety of the nuclear reactor. (Martini et al., 1973; Henry, 1974; Chung, 1978;) However, few studies have presented the spacer grid effect during the reflooding period. Since the grid is an obstruction in the flow passage, it causes an increased pressure drop due to form and skin friction losses. On the other hand, the spacer grid tends to increase the local wall heat transfer. The present work has been performed in a vertical annulus flow channel with various flow conditions. The objective of this paper is to evaluate the effects of a swirl-vane spacer grid on the rewetting phenomena during the reflooding phase

  14. Nuclear and cpDNA sequences combined provide strong inference of higher phylogenetic relationships in the phlox family (Polemoniaceae).

    Science.gov (United States)

    Johnson, Leigh A; Chan, Lauren M; Weese, Terri L; Busby, Lisa D; McMurry, Samuel

    2008-09-01

    Members of the phlox family (Polemoniaceae) serve as useful models for studying various evolutionary and biological processes. Despite its biological importance, no family-wide phylogenetic estimate based on multiple DNA regions with complete generic sampling is available. Here, we analyze one nuclear and five chloroplast DNA sequence regions (nuclear ITS, chloroplast matK, trnL intron plus trnL-trnF intergeneric spacer, and the trnS-trnG, trnD-trnT, and psbM-trnD intergenic spacers) using parsimony and Bayesian methods, as well as assessments of congruence and long branch attraction, to explore phylogenetic relationships among 84 ingroup species representing all currently recognized Polemoniaceae genera. Relationships inferred from the ITS and concatenated chloroplast regions are similar overall. A combined analysis provides strong support for the monophyly of Polemoniaceae and subfamilies Acanthogilioideae, Cobaeoideae, and Polemonioideae. Relationships among subfamilies, and thus for the precise root of Polemoniaceae, remain poorly supported. Within the largest subfamily, Polemonioideae, four clades corresponding to tribes Polemonieae, Phlocideae, Gilieae, and Loeselieae receive strong support. The monogeneric Polemonieae appears sister to Phlocideae. Relationships within Polemonieae, Phlocideae, and Gilieae are mostly consistent between analyses and data permutations. Many relationships within Loeselieae remain uncertain. Overall, inferred phylogenetic relationships support a higher-level classification for Polemoniaceae proposed in 2000.

  15. Effects of spacers on blockage of coolant channels in clad melting accidents

    Energy Technology Data Exchange (ETDEWEB)

    Eggen, D. T.; Scale, T.; Hsieh, S. [Northwestern Univ., Evanston, IL (United States). The Technological Inst.

    1977-07-01

    The elements and configuration of these assemblies are representative of the current design for a GCFR. The fuel elements are stainless-steel clad, mixed-oxide spaced by a grid structure on 250 mm centers with a pitch of 9.5 mm, diameter, 7.2 mm, and cladding thickness, 0.5 m. Three series of experiments have been conducted to study the flow and disposition of molten cladding metal into a lower powered blanket region of the reactor following a loss of flow situation. The first two series used a simulant fuel-element bundle to simplify the experimental procedure and make visual observation possible. The 'fuel' was simulated by mullite rods 6.4 mm in diameter and 610 mm long. These were clad with a 50 Pb/50 Sn alloy tubing which was drawn onto the 'fuel'. The first series used cast spacers with webs of about 0.5-0.55 mm thickness placed 175 and 425 mm from the top end of the assembly. The second series used grid spacers fabricated of 0.25 mm alloy strips. This provided a more accurate representation of the hydraulic diameter. The bundle was encased in a hexagonal glass tube. The bundle was at 22/sup 0/C and the molten alloy was poured at a temperature of 260/sup 0/C (35/sup 0/C superheat). Motion pictures recorded the experiments and the bundle was sectioned for observation. The third set of experiments was done with a stainless steel bundle of 37 elements fabricated of mullite rods, 7.14 mm diameter. The stainless steel cladding had an O.D. of 8.41 mm. The element pitch was 11.1 mm. The grid spacers were prototypic. The experiment was conducted in an inert-gas tube furnace. The 'core fuel' cladding was melted in an induction furnace and the molten liquid flowed through the center seven element channels. X-ray pictures were taken after the tests and the bundle was sectioned for further study.

  16. [Structural organization of 5S ribosomal DNA of Rosa rugosa].

    Science.gov (United States)

    Tynkevych, Iu O; Volkov, R A

    2014-01-01

    In order to clarify molecular organization of the genomic region encoding 5S rRNA in diploid species Rosa rugosa several 5S rDNA repeated units were cloned and sequenced. Analysis of the obtained sequences revealed that only one length variant of 5S rDNA repeated units, which contains intact promoter elements in the intergenic spacer region (IGS) and appears to be transcriptionally active is present in the genome. Additionally, a limited number of 5S rDNA pseudogenes lacking a portion of coding sequence and the complete IGS was detected. A high level of sequence similarity (from 93.7 to 97.5%) between the IGS of major 5S rDNA variants of East Asian R. rugosa and North American R. nitida was found indicating comparatively recent divergence of these species.

  17. DNA polymorphisms and biocontrol of Bacillus antagonistic to citrus bacterial canker with indication of the interference of phyllosphere biofilms.

    Directory of Open Access Journals (Sweden)

    Tzu-Pi Huang

    Full Text Available Citrus bacterial canker caused by Xanthomonas axonopodis pv. citri is a devastating disease resulting in significant crop losses in various citrus cultivars worldwide. A biocontrol agent has not been recommended for this disease. To explore the potential of bacilli native to Taiwan to control this disease, Bacillus species with a broad spectrum of antagonistic activity against various phytopathogens were isolated from plant potting mixes, organic compost and the rhizosphere soil. Seven strains TKS1-1, OF3-16, SP4-17, HSP1, WG6-14, TLB7-7, and WP8-12 showing superior antagonistic activity were chosen for biopesticide development. The genetic identity based on 16S rDNA sequences indicated that all seven native strains were close relatives of the B. subtilis group and appeared to be discrete from the B. cereus group. DNA polymorphisms in strains WG6-14, SP4-17, TKS1-1, and WP8-12, as revealed by repetitive sequence-based PCR with the BOXA1R primers were similar to each other, but different from those of the respective Bacillus type strains. However, molecular typing of the strains using either tDNA-intergenic spacer regions or 16S-23S intergenic transcribed spacer regions was unable to differentiate the strains at the species level. Strains TKS1-1 and WG6-14 attenuated symptom development of citrus bacterial canker, which was found to be correlated with a reduction in colonization and biofilm formation by X. axonopodis pv. citri on leaf surfaces. The application of a Bacillus strain TKS1-1 endospore formulation to the leaf surfaces of citrus reduced the incidence of citrus bacterial canker and could prevent development of the disease.

  18. Effect of electrostatic charge in plastic spacers on the lung delivery of HFA-salbutamol in children

    DEFF Research Database (Denmark)

    Anhøj, J; Bisgaard, H; Lipworth, B J

    1999-01-01

    delivered a significantly (Pplastic spacers reduces lung dose in children by more than two-fold. This is clinically significant and the use of potentially electrostatically charged......AIMS: The effect of the electrostatic charge in plastic spacers in vivo on drug delivery to the lung of hydrofluoroalkane (HFA) salbutamol spray was studied in children. METHODS: Five children, aged 7-12 years, were included in a 3-way crossover randomised single-blind trial. Salbutamol HFA spray...... was delivered on 3 different study days from plastic spacers with mouthpiece. Pre-treatment of the spacers differed between study days: (a) Non-electrostatic 350 ml Babyhaler (coated with benzalkonium chloride) (b) New 350 ml Babyhaler (rinsed in water), and (c) New 145 ml AeroChamber (rinsed in water). Plasma...

  19. Spacer Thickness-Dependent Electron Transport Performance of Titanium Dioxide Thick Film for Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Reda E. El-Shater

    2015-01-01

    Full Text Available A titanium dioxide (P25 film was deposited by cast coating as conductive photoelectrode and subsequently immersed in dye solution (N719 to fabricate the photoanode of dye-sensitized solar cells (DSSCs. A plastic spacer was used as a separation and sealant layer between the photoanode and the counter electrode. The effect of the thickness of this spacer on the transfer of electrons in the liquid electrolyte of the DSSCs was studied by means of both IV curves and electrochemical impedance. Using a spacer thickness range of 20 μm to 50 μm, efficiency ranges from 3.73% to 7.22%. The highest efficiency of 7.22% was obtained with an optimal spacer thickness of 40 μm.

  20. Exploring backbone-cation alkyl spacers for multi-cation side chain anion exchange membranes

    Science.gov (United States)

    Zhu, Liang; Yu, Xuedi; Hickner, Michael A.

    2018-01-01

    In order to systematically study how the arrangement of cations on the side chain and length of alkyl spacers between cations impact the performance of multi-cation AEMs for alkaline fuel cells, a series of polyphenylene oxide (PPO)-based AEMs with different cationic side chains were synthesized. This work resulted in samples with two or three cations in a side chain pendant to the PPO backbone. More importantly, the length of the spacer between cations varied from 3 methylene (-CH2-) (C3) groups to 8 methylene (C8) groups. The highest conductivity, up to 99 mS/cm in liquid water at room temperature, was observed for the triple-cation side chain AEM with pentyl (C5) or hexyl (C6) spacers. The multi-cation AEMs were found to have decreased water uptake and ionic conductivity when the spacer chains between cations were lengthened from pentyl (C5) or hexyl (C6) to octyl (C8) linking groups. The triple-cation membranes with pentyl (C5) or hexyl (C6) groups between cations showed greatest stability after immersion in 1 M NaOH at 80 °C for 500 h.

  1. Measurement and model development of the droplet diameter in rod bundles with spacer grids in the reactor core

    Energy Technology Data Exchange (ETDEWEB)

    No, Hee Cheon; Lee, Eo Hwak; Yoo, Seung Hun; Jin, Hyung Gon; Kim, In Hun [KAIST, Daejeon (Korea, Republic of)

    2010-05-15

    To understand and to predict the heat transfer between superheated steam and droplets properly during reflood phase of LBLOCA of APR1400, it is very important to measure broken droplet sizes by spacer grids. A study, therefore, has been performed to investigate droplet size in rod bundles with spacer grids and to develop a spacer grid droplet size model for safety analysis codes. Experiments were conducted with liquid droplets (SMD of 300{approx}700 {mu}m) impacting on various spacer grids at air superficial velocity of 10 and 20 m/s based on FLECHT SEASET. The test channel and the grids were heated to 150 .deg. C to prevent the formation of liquid film during tests. The spacer grids were designed refer to the Korean fuel rod bundles (Korean Standard Fuel, Plus 7) of APR1400 with various blockage area ratio and grid geometries (strap thickness, mixing vane) and about 15,000 droplets were measured at upstream and downstream of the grids in 16 tests. As a result, the measurement of broken droplet size by spacer grids with photography method is presented and the droplet size model related to spacer grids as a function of blockage area ratio is suggested in this report

  2. Genome-wide identification, characterization and evolutionary analysis of long intergenic noncoding RNAs in cucumber.

    Directory of Open Access Journals (Sweden)

    Zhiqiang Hao

    Full Text Available Long intergenic noncoding RNAs (lincRNAs are intergenic transcripts with a length of at least 200 nt that lack coding potential. Emerging evidence suggests that lincRNAs from animals participate in many fundamental biological processes. However, the systemic identification of lincRNAs has been undertaken in only a few plants. We chose to use cucumber (Cucumis sativus as a model to analyze lincRNAs due to its importance as a model plant for studying sex differentiation and fruit development and the rich genomic and transcriptome data available. The application of a bioinformatics pipeline to multiple types of gene expression data resulted in the identification and characterization of 3,274 lincRNAs. Next, 10 lincRNAs targeted by 17 miRNAs were also explored. Based on co-expression analysis between lincRNAs and mRNAs, 94 lincRNAs were annotated, which may be involved in response to stimuli, multi-organism processes, reproduction, reproductive processes, and growth. Finally, examination of the evolution of lincRNAs showed that most lincRNAs are under purifying selection, while 16 lincRNAs are under natural selection. Our results provide a rich resource for further validation of cucumber lincRNAs and their function. The identification of lincRNAs targeted by miRNAs offers new clues for investigations into the role of lincRNAs in regulating gene expression. Finally, evaluation of the lincRNAs suggested that some lincRNAs are under positive and balancing selection.

  3. Contribution of chloroplast DNA in the biodiversity of some Aegilops ...

    African Journals Online (AJOL)

    Four Aegilops species (Aegilops longissima, Aegilops speltoides, Aegilops searsii and Aegilops caudata) belonging to the family Poaceae were used in this study. Nucleotides of 1651 bp from 5.8 S rRNA gene and the intergenic spacers trnT-trnL and trnL-trnF from the chloroplast DNA were combined together in order to ...

  4. Benthic bacterial diversity in submerged sinkhole ecosystems.

    Science.gov (United States)

    Nold, Stephen C; Pangborn, Joseph B; Zajack, Heidi A; Kendall, Scott T; Rediske, Richard R; Biddanda, Bopaiah A

    2010-01-01

    Physicochemical characterization, automated ribosomal intergenic spacer analysis (ARISA) community profiling, and 16S rRNA gene sequencing approaches were used to study bacterial communities inhabiting submerged Lake Huron sinkholes inundated with hypoxic, sulfate-rich groundwater. Photosynthetic cyanobacterial mats on the sediment surface were dominated by Phormidium autumnale, while deeper, organically rich sediments contained diverse and active bacterial communities.

  5. Gene conversion events and variable degree of homogenization of rDNA loci in cultivars of Brassica napus

    Czech Academy of Sciences Publication Activity Database

    Sochorova, Jana; Coriton, O.; Kuderová, Alena; Lunerová Bedřichová, Jana; Chevre, A.-M.; Kovařík, Aleš

    2017-01-01

    Roč. 119, č. 1 (2017), s. 13-26 ISSN 0305-7364 R&D Projects: GA ČR(CZ) GA13-10057S Institutional support: RVO:68081707 Keywords : ribosomal-rna genes * concerted evolution * intergenic spacer Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Genetics and heredity (medical genetics to be 3) Impact factor: 4.041, year: 2016

  6. Reentrainment of droplet from grid spacer in mist flow portion of LOCA reflood of PWR

    International Nuclear Information System (INIS)

    Lee, S.L.; Cho, S.K.; Sheen, H.J.

    1983-01-01

    An investigation is made on the influence of a quenched grid spacer on the greatly enhanced heat transfer from heated fuel rods during the mist flow phase of emergency reflood of loss of coolant accident (LOCA) of a pressurized water reactor (PWR). The situation for the case of a dry grid spacer before its quenching has not been covered in this study. The experimental technique used is a relatively simple optical scheme which combines the reference-mode laser-Doppler anemometry making use of the scattering of a light beam from a droplet. The results reveal that the large droplets in the mist flow, which are intercepted by the grid spacer, are responsible for the creation of a large number of smaller droplets. These small droplets, due to their large surface area to mass ratios, can serve as superb evaporative cooling agents to heat transfer downstream of the grid spacer

  7. Efficient and colour-stable hybrid white organic light-emitting diodes utilizing electron-hole balanced spacers

    International Nuclear Information System (INIS)

    Leem, Dong-Seok; Kim, Ji Whan; Kim, Jang-Joo; Jung, Sung Ouk; Kim, Seul-Ong; Kwon, Soon-Ki; Kim, Se Hoon; Kim, Kee Young; Kim, Yun-Hi

    2010-01-01

    High-efficiency two-colour white organic light-emitting diodes (WOLEDs) comprising a newly synthesized iridium complex orange phosphor ((impy) 2 Ir(acac)) and a blue fluorophor (BD012) have been realized by placing several kinds of thin spacers between two emitters. Hybrid WOLEDs with a spacer composed of a hole-transporting N,N-dicarbazolyl-3,5-benzene (mCP) and an electron-transporting 4,7-diphenyl-1,10-phenanthroline (Bphen) exhibit a high external quantum efficiency (EQE) of up to 8.4% and a negligible colour change (the colour coordinate of (0.39, 0.41) at 1000 cd m -2 ) with increasing brightness, whereas the device using a hole-transporting mCP spacer shows a relatively low EQE of 6.2% and a large shift of emitting colour with increasing brightness. Device performance is further characterized based on the charge transport behaviour of the spacers inserted between the two emitters.

  8. Similar Results in Children with Asthma for Steady State Pharmacokinetic Parameters of Ciclesonide Inhaled with or without Spacer

    Directory of Open Access Journals (Sweden)

    H. Boss

    2010-01-01

    Full Text Available Background Ciclesonide is an inhaled corticosteroid administered by a metered dose inhaler (MDI to treat bronchial asthma. After inhalation, the inactive ciclesonide is converted by esterases in the airways to active metabolite desisobutyryl-ciclesonide (des-CIC. Aim To compare the pharmacokinetic (PK parameters of des-CIC in children after administration of therapeutic dose of ciclesonide with and without spacer (AeroChamber Plus™. Methods Open-label, 3 period, cross over, repeated dose, PK study in 37 children with mild to moderate stable asthma (age: 6–11 y; body weight: 20–53 kg. During each 7-day treatment period, ciclesonide was inhaled once in the morning: A 160 μg MDI with spacer, B 80 μg MDI with spacer, and C 160 μg MDI without spacer. Serum PK parameters of ciclesonide and des-CIC were determined on Day 7 of each period. The primary PK parameters were the AUC τ and C max for des-CIC. Results Inhaling ciclesonide with spacer led to a dose proportional systemic exposure (AUC τ of des-CIC (0.316 μg*h/L for 80 μg and 0.663 μg*h/L for 160 μg. The dose-normalized systemic exposure for des-CIC (based on AUC τ was 27% higher after inhalation of ciclesonide 80 μg or 160 μg with spacer than without spacer; the corresponding C max values for des-CIC were, respectively, 63% and 55% higher with spacer. No clinically relevant abnormalities or adverse drug reactions were observed. Conclusions Inhalation of therapeutic ciclesonide dose with spacer led to a slight increase in the systemic exposure of des-CIC, which does not warrant dose adjustment.

  9. Experimental benchmark data for PWR rod bundle with spacer-grids

    International Nuclear Information System (INIS)

    Dominguez-Ontiveros, Elvis E.; Hassan, Yassin A.; Conner, Michael E.; Karoutas, Zeses

    2012-01-01

    In numerical simulations of fuel rod bundle flow fields, the unsteady Navier–Stokes equations have to be solved in order to determine the time (phase) dependent characteristics of the flow. In order to validate the simulations results, detailed comparison with experimental data must be done. Experiments investigating complex flows in rod bundles with spacer grids that have mixing devices (such as flow mixing vanes) have mostly been performed using single-point measurements. In order to obtain more details and insight on the discrepancies between experimental and numerical data as well as to obtain a global understanding of the causes of these discrepancies, comparisons of the distributions of complete phase-averaged velocity and turbulence fields for various locations near spacer-grids should be performed. The experimental technique Particle Image Velocimetry (PIV) is capable of providing such benchmark data. This paper describes an experimental database obtained using two-dimensional Time Resolved Particle Image Velocimetry (TR-PIV) measurements within a 5 × 5 PWR rod bundle with spacer-grids that have flow mixing vanes. One of the unique characteristic of this set-up is the use of the Matched Index of Refraction technique employed in this investigation to allow complete optical access to the rod bundle. This unique feature allows flow visualization and measurement within the bundle without rod obstruction. This approach also allows the use of high temporal and spatial non-intrusive dynamic measurement techniques namely TR-PIV to investigate the flow evolution below and immediately above the spacer. The experimental data presented in this paper includes explanation of the various cases tested such as test rig dimensions, measurement zones, the test equipment and the boundary conditions in order to provide appropriate data for comparison with Computational Fluid Dynamics (CFD) simulations. Turbulence parameters of the obtained data are presented in order to gain

  10. Prevalence and Characteristics of Streptococcus canis Strains Isolated from Dogs and Cats

    Directory of Open Access Journals (Sweden)

    P. Lysková

    2007-01-01

    Full Text Available To determine the prevalence of Streptococcus canis in dogs and cats, a total of 926 swabs were examined bacteriologically in the period from 2003 to 2005. Eighty-six isolates obtained from various anatomical locations were further characterized for their phenotypic properties. The most frequently isolated biotype produced phosphatase, leucine amidopeptidase, arginine dihydrolase, alpha-D- and beta-D-galactosidase and fermented lactose and ribose. Additional identification by species-specific amplification of the 16S-23S rRNA intergenic spacer region was consistent with S. canis. All isolates were susceptible to penicillin G and ampicillin. The least effective antimicrobial agent was found to be tetracycline (only 33.8% of susceptible strains.

  11. Milky hemolymph syndrome (MHS) in spiny lobsters, penaeid shrimp and crabs.

    Science.gov (United States)

    Nunan, Linda M; Poulos, Bonnie T; Navarro, Solangel; Redman, Rita M; Lightner, Donald V

    2010-09-02

    Black tiger shrimp Penaeus monodon, European shore crab Carcinus maenas and spiny lobster Panulirus spp. can be affected by milky hemolymph syndrome (MHS). Four rickettsia-like bacteria (RLB) isolates of MHS originating from 5 geographical areas have been identified to date. The histopathology of the disease was characterized and a multiplex PCR assay was developed for detection of the 4 bacterial isolates. The 16S rRNA gene and 16-23S rRNA intergenic spacer region (ISR) were used to examine the phylogeny of the MHS isolates. Although the pathology of this disease appears similar in the various different hosts, sequencing and examination of the phylogenetic relationships reveal 4 distinct RLB involved in the infection process.

  12. An Unusual Case of White Piedra Due to Trichosporon inkin Mimicking Trichobacteriosis.

    Science.gov (United States)

    Zhuang, Kaiwen; Ran, Xin; Dai, Yaling; Tang, Jiaoqing; Yang, Qin; Pradhan, Sushmita; Ran, Yuping

    2016-12-01

    White piedra is a superficial mycosis characterized by soft, white-to-tan, irregular nodules attached to the hair shafts. A 36-year-old man presented with small lumps in his pubic hair, without any other symptoms. The clinical features were suggestive of trichobacteriosis. Pathology analysis of the infected hair revealed that the concretions surrounding the hair shaft were full of fungal elements, parts of which had invaded into the cuticle. Culture on Sabouraud dextrose agar grew creamy, yellow-white colonies identified as Trichosporon inkin by the sequence of the nuclear ribosomal intergenic spacer region. The condition was treated by shaving the pubic hair and administering antifungal therapy (oral itraconazole and topical ketoconazole).

  13. Concerted evolution rapidly eliminates sequence variation in rDNA coding regions but not in intergenic spacers in Nicotiana tabacum allotetraploid

    Czech Academy of Sciences Publication Activity Database

    Lunerová Bedřichová, Jana; Renny-Byfield, S.; Matyášek, Roman; Leitch, A.; Kovařík, Aleš

    2017-01-01

    Roč. 303, č. 8 (2017), s. 1043-1060 ISSN 0378-2697 R&D Projects: GA ČR(CZ) GA17-11642S; GA ČR(CZ) GC16-02149J Institutional support: RVO:68081707 Keywords : Concerted evolution * Immunomodulation * Neutrophils Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Genetics and heredity (medical genetics to be 3) Impact factor: 1.239, year: 2016

  14. Diagnosis Of Persistent Infection In Prosthetic Two-Stage Exchange: PCR analysis of Sonication fluid From Bone Cement Spacers.

    Science.gov (United States)

    Mariaux, Sandrine; Tafin, Ulrika Furustrand; Borens, Olivier

    2017-01-01

    Introduction: When treating periprosthetic joint infections with a two-stage procedure, antibiotic-impregnated spacers are used in the interval between removal of prosthesis and reimplantation. According to our experience, cultures of sonicated spacers are most often negative. The objective of our study was to investigate whether PCR analysis would improve the detection of bacteria in the spacer sonication fluid. Methods: A prospective monocentric study was performed from September 2014 to January 2016. Inclusion criteria were two-stage procedure for prosthetic infection and agreement of the patient to participate in the study. Beside tissues samples and sonication, broad range bacterial PCRs, specific S. aureus PCRs and Unyvero-multiplex PCRs were performed on the sonicated spacer fluid. Results: 30 patients were identified (15 hip, 14 knee and 1 ankle replacements). At reimplantation, cultures of tissue samples and spacer sonication fluid were all negative. Broad range PCRs were all negative. Specific S. aureus PCRs were positive in 5 cases. We had two persistent infections and four cases of infection recurrence were observed, with bacteria different than for the initial infection in three cases. Conclusion: The three different types of PCRs did not detect any bacteria in spacer sonication fluid that was culture-negative. In our study, PCR did not improve the bacterial detection and did not help to predict whether the patient will present a persistent or recurrent infection. Prosthetic 2-stage exchange with short interval and antibiotic-impregnated spacer is an efficient treatment to eradicate infection as both culture- and molecular-based methods were unable to detect bacteria in spacer sonication fluid after reimplantation.

  15. Phylogenetic analysis of cercospora and mycosphaerella based on the internal transcribed spacer region of ribosomal DNA.

    Science.gov (United States)

    Goodwin, S B; Dunkle, L D; Zismann, V L

    2001-07-01

    ABSTRACT Most of the 3,000 named species in the genus Cercospora have no known sexual stage, although a Mycosphaerella teleomorph has been identified for a few. Mycosphaerella is an extremely large and important genus of plant pathogens, with more than 1,800 named species and at least 43 associated anamorph genera. The goal of this research was to perform a large-scale phylogenetic analysis to test hypotheses about the past evolutionary history of Cercospora and Mycosphaerella. Based on the phylogenetic analysis of internal transcribed spacer (ITS) sequence data (ITS1, 5.8S rRNA gene, ITS2), the genus Mycosphaerella is monophyletic. In contrast, many anamorph genera within Mycosphaerella were polyphyletic and were not useful for grouping species. One exception was Cercospora, which formed a highly supported monophyletic group. Most Cercospora species from cereal crops formed a subgroup within the main Cercospora cluster. Only species within the Cercospora cluster produced the toxin cercosporin, suggesting that the ability to produce this compound had a single evolutionary origin. Intraspecific variation for 25 taxa in the Mycosphaerella clade averaged 1.7 nucleotides (nts) in the ITS region. Thus, isolates with ITS sequences that differ by two or more nucleotides may be distinct species. ITS sequences of groups I and II of the gray leaf spot pathogen Cercospora zeae-maydis differed by 7 nts and clearly represent different species. There were 6.5 nt differences on average between the ITS sequences of the sorghum pathogen Cercospora sorghi and the maize pathogen Cercospora sorghi var. maydis, indicating that the latter is a separate species and not simply a variety of Cercospora sorghi. The large monophyletic Mycosphaerella cluster contained a number of anamorph genera with no known teleomorph associations. Therefore, the number of anamorph genera related to Mycosphaerella may be much larger than suspected previously.

  16. Impact of feed spacer and membrane modification by hydrophilic, bactericidal and biocidal coating on biofouling control

    KAUST Repository

    Araú jo, Paula A.; Miller, Daniel J.; Correia, Patrí cia B.; van Loosdrecht, Mark C.M.; Kruithof, Joop C.; Freeman, Benny Dean; Paul, Donald; Vrouwenvelder, Johannes S.

    2012-01-01

    surface modification agents expected to resist protein and bacterial adhesion, while copper feed spacer coatings and biocides infused in feed spacers are expected to restrict biological growth. Our studies showed that polydopamine and polydopamine-. g

  17. Cervical interfacet spacers and maintenance of cervical lordosis.

    Science.gov (United States)

    Tan, Lee A; Straus, David C; Traynelis, Vincent C

    2015-05-01

    OBJECT The cervical interfacet spacer (CIS) is a relatively new technology that can increase foraminal height and area by facet distraction. These offer the potential to provide indirect neuroforaminal decompression while simultaneously enhancing fusion potential due to the relatively large osteoconductive surface area and compressive forces exerted on the grafts. These potential benefits, along with the relative ease of implantation during posterior cervical fusion procedures, make the CIS an attractive adjuvant in the management of cervical pathology. One concern with the use of interfacet spacers is the theoretical risk of inducing iatrogenic kyphosis. This work tests the hypothesis that interfacet spacers are associated with loss of cervical lordosis. METHODS Records from patients undergoing posterior cervical fusion at Rush University Medical Center between March 2011 and December 2012 were reviewed. The FacetLift CISs were used in all patients. Preoperative and postoperative radiographic data were reviewed and the Ishihara indices and cervical lordotic angles were measured and recorded. Statistical analyses were performed using STATA software. RESULTS A total of 64 patients were identified in whom 154 cervical levels were implanted with machined allograft interfacet spacers. Of these, 15 patients underwent anterior-posterior fusions, 4 underwent anterior-posterior-anterior fusions, and the remaining 45 patients underwent posterior-only fusions. In the 45 patients with posterior-only fusions, a total of 110 levels were treated with spacers. There were 14 patients (31%) with a single level treated, 16 patients (36%) with two levels treated, 5 patients (11%) with three levels treated, 5 patients (11%) with four levels treated, 1 patient (2%) with five levels treated, and 4 patients (9%) with six levels treated. Complete radiographic data were available in 38 of 45 patients (84%). On average, radiographic follow-up was obtained at 256.9 days (range 48-524 days

  18. Efficient and colour-stable hybrid white organic light-emitting diodes utilizing electron-hole balanced spacers

    Energy Technology Data Exchange (ETDEWEB)

    Leem, Dong-Seok; Kim, Ji Whan; Kim, Jang-Joo [Department of Materials Science and Engineering, and OLED Center, Seoul National University, Seoul 151-744 (Korea, Republic of); Jung, Sung Ouk; Kim, Seul-Ong; Kwon, Soon-Ki [School of Materials Science and Engineering, and Engineering Research Institute (ERI), Gyeongsang National University, Jinju 660-701 (Korea, Republic of); Kim, Se Hoon; Kim, Kee Young [Dongwoo Fine-Chem Co., Ltd, Pyeongtaek 451-822 (Korea, Republic of); Kim, Yun-Hi, E-mail: jjkim@snu.ac.k, E-mail: skwon@gnu.ac.k [Department of Chemistry and RINS, Gyeongsang National University, Jinju 660-701 (Korea, Republic of)

    2010-10-13

    High-efficiency two-colour white organic light-emitting diodes (WOLEDs) comprising a newly synthesized iridium complex orange phosphor ((impy){sub 2}Ir(acac)) and a blue fluorophor (BD012) have been realized by placing several kinds of thin spacers between two emitters. Hybrid WOLEDs with a spacer composed of a hole-transporting N,N-dicarbazolyl-3,5-benzene (mCP) and an electron-transporting 4,7-diphenyl-1,10-phenanthroline (Bphen) exhibit a high external quantum efficiency (EQE) of up to 8.4% and a negligible colour change (the colour coordinate of (0.39, 0.41) at 1000 cd m{sup -2}) with increasing brightness, whereas the device using a hole-transporting mCP spacer shows a relatively low EQE of 6.2% and a large shift of emitting colour with increasing brightness. Device performance is further characterized based on the charge transport behaviour of the spacers inserted between the two emitters.

  19. Abundant and diverse clustered regularly interspaced short palindromic repeat spacers in Clostridium difficile strains and prophages target multiple phage types within this pathogen.

    Science.gov (United States)

    Hargreaves, Katherine R; Flores, Cesar O; Lawley, Trevor D; Clokie, Martha R J

    2014-08-26

    Clostridium difficile is an important human-pathogenic bacterium causing antibiotic-associated nosocomial infections worldwide. Mobile genetic elements and bacteriophages have helped shape C. difficile genome evolution. In many bacteria, phage infection may be controlled by a form of bacterial immunity called the clustered regularly interspaced short palindromic repeats/CRISPR-associated (CRISPR/Cas) system. This uses acquired short nucleotide sequences (spacers) to target homologous sequences (protospacers) in phage genomes. C. difficile carries multiple CRISPR arrays, and in this paper we examine the relationships between the host- and phage-carried elements of the system. We detected multiple matches between spacers and regions in 31 C. difficile phage and prophage genomes. A subset of the spacers was located in prophage-carried CRISPR arrays. The CRISPR spacer profiles generated suggest that related phages would have similar host ranges. Furthermore, we show that C. difficile strains of the same ribotype could either have similar or divergent CRISPR contents. Both synonymous and nonsynonymous mutations in the protospacer sequences were identified, as well as differences in the protospacer adjacent motif (PAM), which could explain how phages escape this system. This paper illustrates how the distribution and diversity of CRISPR spacers in C. difficile, and its prophages, could modulate phage predation for this pathogen and impact upon its evolution and pathogenicity. Clostridium difficile is a significant bacterial human pathogen which undergoes continual genome evolution, resulting in the emergence of new virulent strains. Phages are major facilitators of genome evolution in other bacterial species, and we use sequence analysis-based approaches in order to examine whether the CRISPR/Cas system could control these interactions across divergent C. difficile strains. The presence of spacer sequences in prophages that are homologous to phage genomes raises an

  20. Experimental and numerical characterization of the water flow in spacer-filled channels of spiral-wound membranes

    KAUST Repository

    Bucs, Szilard; Valladares Linares, Rodrigo; Marston, Jeremy O.; Radu, Andrea I.; Vrouwenvelder, Johannes S.; Picioreanu, Cristian

    2015-01-01

    Micro-scale flow distribution in spacer-filled flow channels of spiral-wound membrane modules was determined with a particle image velocimetry system (PIV), aiming to elucidate the flow behaviour in spacer-filled flow channels. Two-dimensional water

  1. Custom-made hinged spacers in revision knee surgery for patients with infection, bone loss and instability.

    Science.gov (United States)

    Macmull, S; Bartlett, W; Miles, J; Blunn, G W; Pollock, R C; Carrington, R W J; Skinner, J A; Cannon, S R; Briggs, T W R

    2010-12-01

    Polymethyl methacrylate spacers are commonly used during staged revision knee arthroplasty for infection. In cases with extensive bone loss and ligament instability, such spacers may not preserve limb length, joint stability and motion. We report a retrospective case series of 19 consecutive patients using a custom-made cobalt chrome hinged spacer with antibiotic-loaded cement. The "SMILES spacer" was used at first-stage revision knee arthroplasty for chronic infection associated with a significant bone loss due to failed revision total knee replacement in 11 patients (58%), tumour endoprosthesis in four patients (21%), primary knee replacement in two patients (11%) and infected metalwork following fracture or osteotomy in a further two patients (11%). Mean follow-up was 38 months (range 24-70). In 12 (63%) patients, infection was eradicated, three patients (16%) had persistent infection and four (21%) developed further infection after initially successful second-stage surgery. Above knee amputation for persistent infection was performed in two patients. In this particularly difficult to treat population, the SMILES spacer two-stage technique has demonstrated encouraging results and presents an attractive alternative to arthrodesis or amputation. Copyright © 2009 Elsevier B.V. All rights reserved.

  2. Highly Efficient White Organic Light-Emitting Diodes with Ultrathin Emissive Layers and a Spacer-Free Structure

    Science.gov (United States)

    Wu, Shengfan; Li, Sihua; Sun, Qi; Huang, Chenchao; Fung, Man-Keung

    2016-05-01

    Ultrathin emissive layers (UEMLs) of phosphorescent materials with a layer thickness of less than 0.3 nm were introduced for high-efficiency organic light-emitting diodes (OLEDs). All the UEMLs for white OLEDs can be prepared without the use of interlayers or spacers. Compared with devices fabricated with interlayers inserted in-between the UEMLs, our spacer-free structure not only significantly improves device efficiency, but also simplifies the fabrication process, thus it has a great potential in lowering the cost of OLED panels. In addition, its spacer-free structure decreases the number of interfaces which often introduce unnecessary energy barriers in these devices. In the present work, UEMLs of red, green and blue-emitting phosphorescent materials and yellow and blue phosphorescent emitters are utilized for the demonstration of spacer-free white OLEDs. Upon optimization of the device structure, we demonstrated spacer-free and simple-structured white-emitting OLEDs with a good device performance. The current and power efficiencies of our white-emitting devices are as high as 56.0 cd/A and 55.5 lm/W, respectively. These efficiencies are the highest ever reported for OLEDs fabricated with the UEML approach.

  3. Spacer Facial Artery Musculomucosal Flap: Simultaneous Closure of Oronasal Fistulas and Palatal Lengthening.

    Science.gov (United States)

    Lee, Jonathan Y; Alizadeh, Kaveh

    2016-01-01

    In this series, the authors describe a modification of the facial artery musculomucosal flap for oronasal fistula repair. The spacer facial artery musculomucosal flap technique is characterized by a pedicle inset into the retromolar trigone and palate, obviating a second operative stage. This was performed in 14 patients with a 5.2-cm mean fistula size. Average follow-up was 4.3 years, with one partial flap necrosis but no recurrent oronasal fistula. There was a mean decrease of 18 percent in the distance between the velum and the posterior pharyngeal wall. The spacer facial artery musculomucosal flap provides a single-stage reconstruction of oronasal fistula while lengthening the palate through a pushback mechanism. Although further study of velopharyngeal function is needed, the spacer facial artery musculomucosal flap may be beneficial for patients with a short velum and an oronasal fistula. Therapeutic, IV.

  4. AA stacking, tribological and electronic properties of double-layer graphene with krypton spacer.

    Science.gov (United States)

    Popov, Andrey M; Lebedeva, Irina V; Knizhnik, Andrey A; Lozovik, Yurii E; Potapkin, Boris V; Poklonski, Nikolai A; Siahlo, Andrei I; Vyrko, Sergey A

    2013-10-21

    Structural, energetic, and tribological characteristics of double-layer graphene with commensurate and incommensurate krypton spacers of nearly monolayer coverage are studied within the van der Waals-corrected density functional theory. It is shown that when the spacer is in the commensurate phase, the graphene layers have the AA stacking. For this phase, the barriers to relative in-plane translational and rotational motion and the shear mode frequency of the graphene layers are calculated. For the incommensurate phase, both of the barriers are found to be negligibly small. A considerable change of tunneling conductance between the graphene layers separated by the commensurate krypton spacer at their relative subangstrom displacement is revealed by the use of the Bardeen method. The possibility of nanoelectromechanical systems based on the studied tribological and electronic properties of the considered heterostructures is discussed.

  5. Two pion correlation from SPACER

    International Nuclear Information System (INIS)

    Csoergoe, T.; Zimanyi, J.; Pratt, S.

    1989-12-01

    The correlation function for neutral and negative pions produced in ultrarelativistic heavy ion collisions was calculated without free parameters based on a space-time version of the LUND model, called SPACER: Simulation of Phase space distribution of Atomic nuclear Collisions in Energetic Reactions. This method includes the effect of Bose correlations for the emitted pion pair. Effects arising from correlations between space-time and momentum space distributions are investigated. The results are compared to the data of two different experiments. The role and interpretation of the chaocity parameter are discussed. (D.G.) 14 refs.; 4 figs

  6. Ribosomal DNA internal transcribed spacer 1 and internal ...

    African Journals Online (AJOL)

    USER

    2010-07-26

    Jul 26, 2010 ... in some East Asian countries such as China, Korea and. *Corresponding author. E-mail: soonkwan@kangwon.ac.kr. Tel: +82 33 250 6476. Fax: +82 33 250 6470. Abbreviations: nrDNA, Nuclear ribosomal DNA; ITS, internal transcribed spacer; PCR, polymerase chain reaction; BLAST, basic local alignment ...

  7. Preclinical investigations towards the first spacer gel application in prostate cancer treatment during particle therapy at HIT

    International Nuclear Information System (INIS)

    Ruciński, Antoni; Parodi, Katia; Jäkel, Oliver; Haberer, Thomas; Bauer, Julia; Campbell, Patrick; Brons, Stephan; Unholtz, Daniel; Habl, Gregor; Herfarth, Klaus; Debus, Jürgen; Bert, Christoph

    2013-01-01

    The application of spacer gel represents a promising approach to reliably spare the rectal frontal wall during particle therapy (IJROBP 76:1251-1258, 2010). In order to qualify the spacer gel for the clinical use in particle therapy, a variety of measurements were performed in order to ensure the biological compatibility of the gel, its physical stability during and after the irradiation, and a proper definition of the gel in terms of the Hounsfield Unit (HU) values for the treatment planning system. The potential for the use of the spacer gel for particle therapy monitoring with off-line Positron Emission Tomography (PET) was also investigated. The spacer gel implanted to the prostate patient in direct neighbourhood to the clinical target volume does not interfere with the particle therapy treatment planning procedure applied at Heidelberg Ion Beam Therapy Centre (HIT). The performed measurements show that Bragg-peak position of the particles can be properly predicted on the basis of computed tomography imaging with the treatment planning system used at HIT (measured water equivalent path length of 1.011 ±0.011 (2σ), measured Hounsfield Unit of 28.9 ±6.1 (2σ)). The spacer gel samples remain physically unchanged after irradiation with a dose exceeding the therapeutic dose level. The independently measured Bragg-Peak position does not change within the time interval of 10 weeks. As a result of the presented experiments, the first clinical application of spacer gel implant during prostate cancer treatment with carbon ions and protons was possible at HIT in 2012. The reported pre-clinical investigations demonstrate that use of spacer gel is safe in particle therapy in presence of therapy target motion and patient positioning induced particle range variations. The spacer gel injected between prostate and rectum enlarge the distance between both organs, which is expected to clinically significantly decrease the undesirable exposure of the most critical organ at risk

  8. Time spans and spacers : Molecular phylogenetic explorations in the Cladophora complex (Chlorophyta) from the perspective of rDNA gene and spacer sequences

    NARCIS (Netherlands)

    Bakker, Frederik Theodoor

    1995-01-01

    In this study, phylogenetic relationships among genera, species and biogeographic representatives of single Cladophora species within the Cladophorales were analyzed using rDNA gene and spacer sequences. Based on phylogenetic analysis of 18S rRNA gene sequences, the Cladophora complex is shown to be

  9. SU-E-T-284: Dose Plan Optimization When Using Hydrogel Prostate-Rectum Spacer: A Single Institution Experience

    Energy Technology Data Exchange (ETDEWEB)

    Rajecki, M; Thurber, A; Catalfamo, F; Duff, M; Shah, D [Cancer Care of Western New York, Cheektowaga, NY (United States)

    2015-06-15

    Purpose: To describe rectal dose reduction achieved and techniques used to take advantage of the increased peri-rectal spacing provided by injected polyethylene-glycol. Methods: Thirty prostate cancer patents were 2:1 randomized during a clinical trial to evaluate the effectiveness of injected poly-ethylene glycol hydrogel (SpaceOAR System) in creating space between the prostate and the anterior rectal wall. All patients received a baseline CT/MR scan and baseline IMRT treatment plan. Patients were randomized to receive hydrogel injection (n=20) or Control (n=10), followed by another CT/MR scan and treatment plan (single arc VMAT, 6 MV photons, 79.2 Gy, 44 fractions). Additional optimization structures were employed to constrain the dose to the rectum; specifically an avoidance structure to limit V75 <15%, and a control structure to limit the maximum relative dose <105% in the interface region of the anterior rectal wall and the prostate planning target volume. Dose volumetric data was analyzed for rectal volumes receiving 60 through 80 Gy. Results: Rectal dose reduction was observed in all patients who received the hydrogel. Volumetric analysis indicates a median rectal volume and (reduction from baseline plan) following spacer application of 4.9% (8.9%) at V60Gy, 3.8% (8.1%) at V65Gy, 2.5% (7.2%) at V70Gy, 1.6% (5.8%) at V75Gy, and 0.5% (2.5%) at V80Gy. Conclusion: Relative to planning without spacers, rectal dose constraints of 5%, 4%, 3%, 2%, 1% for V60, V65, V70, V75, and V80, should be obtainable when peri-rectal spacers are used. The combined effect of increased peri-rectal space provided by the hydrogel, with strict optimization objectives, resulted in reduced dose to the rectum. To maximize benefit, strict optimization objectives and reduced rectal dose constraints should be employed when creating plans for patients with perirectal spacers. Clinical Trial for SpaceOAR product conducted by Augmenix,Inc. The research site was paid to be a participating site.

  10. SU-E-T-284: Dose Plan Optimization When Using Hydrogel Prostate-Rectum Spacer: A Single Institution Experience

    International Nuclear Information System (INIS)

    Rajecki, M; Thurber, A; Catalfamo, F; Duff, M; Shah, D

    2015-01-01

    Purpose: To describe rectal dose reduction achieved and techniques used to take advantage of the increased peri-rectal spacing provided by injected polyethylene-glycol. Methods: Thirty prostate cancer patents were 2:1 randomized during a clinical trial to evaluate the effectiveness of injected poly-ethylene glycol hydrogel (SpaceOAR System) in creating space between the prostate and the anterior rectal wall. All patients received a baseline CT/MR scan and baseline IMRT treatment plan. Patients were randomized to receive hydrogel injection (n=20) or Control (n=10), followed by another CT/MR scan and treatment plan (single arc VMAT, 6 MV photons, 79.2 Gy, 44 fractions). Additional optimization structures were employed to constrain the dose to the rectum; specifically an avoidance structure to limit V75 <15%, and a control structure to limit the maximum relative dose <105% in the interface region of the anterior rectal wall and the prostate planning target volume. Dose volumetric data was analyzed for rectal volumes receiving 60 through 80 Gy. Results: Rectal dose reduction was observed in all patients who received the hydrogel. Volumetric analysis indicates a median rectal volume and (reduction from baseline plan) following spacer application of 4.9% (8.9%) at V60Gy, 3.8% (8.1%) at V65Gy, 2.5% (7.2%) at V70Gy, 1.6% (5.8%) at V75Gy, and 0.5% (2.5%) at V80Gy. Conclusion: Relative to planning without spacers, rectal dose constraints of 5%, 4%, 3%, 2%, 1% for V60, V65, V70, V75, and V80, should be obtainable when peri-rectal spacers are used. The combined effect of increased peri-rectal space provided by the hydrogel, with strict optimization objectives, resulted in reduced dose to the rectum. To maximize benefit, strict optimization objectives and reduced rectal dose constraints should be employed when creating plans for patients with perirectal spacers. Clinical Trial for SpaceOAR product conducted by Augmenix,Inc. The research site was paid to be a participating site

  11. On the Origin of Reverse Transcriptase-Using CRISPR-Cas Systems and Their Hyperdiverse, Enigmatic Spacer Repertoires.

    Science.gov (United States)

    Silas, Sukrit; Makarova, Kira S; Shmakov, Sergey; Páez-Espino, David; Mohr, Georg; Liu, Yi; Davison, Michelle; Roux, Simon; Krishnamurthy, Siddharth R; Fu, Becky Xu Hua; Hansen, Loren L; Wang, David; Sullivan, Matthew B; Millard, Andrew; Clokie, Martha R; Bhaya, Devaki; Lambowitz, Alan M; Kyrpides, Nikos C; Koonin, Eugene V; Fire, Andrew Z

    2017-07-11

    Cas1 integrase is the key enzyme of the clustered regularly interspaced short palindromic repeat (CRISPR)-Cas adaptation module that mediates acquisition of spacers derived from foreign DNA by CRISPR arrays. In diverse bacteria, the cas1 gene is fused (or adjacent) to a gene encoding a reverse transcriptase (RT) related to group II intron RTs. An RT-Cas1 fusion protein has been recently shown to enable acquisition of CRISPR spacers from RNA. Phylogenetic analysis of the CRISPR-associated RTs demonstrates monophyly of the RT-Cas1 fusion, and coevolution of the RT and Cas1 domains. Nearly all such RTs are present within type III CRISPR-Cas loci, but their phylogeny does not parallel the CRISPR-Cas type classification, indicating that RT-Cas1 is an autonomous functional module that is disseminated by horizontal gene transfer and can function with diverse type III systems. To compare the sequence pools sampled by RT-Cas1-associated and RT-lacking CRISPR-Cas systems, we obtained samples of a commercially grown cyanobacterium- Arthrospira platensis Sequencing of the CRISPR arrays uncovered a highly diverse population of spacers. Spacer diversity was particularly striking for the RT-Cas1-containing type III-B system, where no saturation was evident even with millions of sequences analyzed. In contrast, analysis of the RT-lacking type III-D system yielded a highly diverse pool but reached a point where fewer novel spacers were recovered as sequencing depth was increased. Matches could be identified for a small fraction of the non-RT-Cas1-associated spacers, and for only a single RT-Cas1-associated spacer. Thus, the principal source(s) of the spacers, particularly the hypervariable spacer repertoire of the RT-associated arrays, remains unknown. IMPORTANCE While the majority of CRISPR-Cas immune systems adapt to foreign genetic elements by capturing segments of invasive DNA, some systems carry reverse transcriptases (RTs) that enable adaptation to RNA molecules. From

  12. Single-Stage Treatment of Osteomyelitis for Digital Salvage by Using an Antibiotic-Eluting, Methylmethacrylate Joint-Spanning Spacer.

    Science.gov (United States)

    Aimé, Victoria L; Kidwell, John T; Webb, Leland H

    2017-06-01

    Osteomyelitis of the digit is a challenging problem that can result in amputation. We describe 13 cases of osteomyelitis involving bones of the hand managed with a novel technique. We reviewed records of 12 patients (13 digits) who had joint-spanning, antibiotic-eluting (tobramycin or vancomycin), methylmethacrylate spacers placed as definitive, single-stage treatment for digital osteomyelitis. The primary outcome was digit salvage. Secondary outcomes were infection eradication (no recurrence at 3 months) and spacer removal. Patients were followed up until the infection resolved (ie, no cutaneous signs of infection, including pain, erythema, or swelling). At a mean of 24 months, 10 of 13 infections had successful one-stage treatment. One patient required a second operation to revise a soft tissue flap but the spacer remained in place. Two spacers were removed because of malalignment. An antibiotic-eluting methylmethacrylate spacer is an innovative treatment for digital osteomyelitis. In 12 consecutive patients (13 digits), we successfully salvaged the digit. Copyright © 2017 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  13. CFD analysis on mixing effects of spacer grids with different dimples and sizes for advanced fuel assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Yang, B.W.; Zhang, H.; Han, B.; Zha, Y.D.; Shan, J.Q. [Xi' an Jiaotong Univ. (China). School of Nuclear Science and Technology

    2016-07-15

    The thermal hydraulic characteristics of a mixing vane grid are largely dependent on the structure of key components, such as strip, spring, dimple, weld nugget, as well as the mixing vane configuration. In this paper, several types of spacer grids with different dimple shapes are modeled under subcooled boiling conditions. Prior to the application of CFD on the dimple shape analysis, the mixing effects of spacer grids were studied. After the dimple shape analysis, the side channel effect is discussed by comparing the simulation results of a 3 x 3 and a 5 x 5 spacer grid. The two phase flow CFD models in this study are validated through simple geometry showing that the calculated void fraction is in good agreement with the experimental data. The dimple comparison result shows that varying dimple structures can result in different temperatures, lateral velocities and void fraction distributions downstream of the spacer grids. Comparison of two sizes of spacer grids demonstrate that the side channel generates different flow distribution pattern in the center channel.

  14. Spacer length impacts the efficacy of targeted docetaxel conjugates in prostate-specific membrane antigen expressing prostate cancer.

    Science.gov (United States)

    Peng, Zheng-Hong; Sima, Monika; Salama, Mohamed E; Kopečková, Pavla; Kopeček, Jindřich

    2013-12-01

    Combination of targeted delivery and controlled release is a powerful technique for cancer treatment. In this paper, we describe the design, synthesis, structure validation and biological properties of targeted and non-targeted N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer-docetaxel conjugates. Docetaxel (DTX) was conjugated to HPMA copolymer via a tetrapeptide spacer (-GFLG-). 3-(1,3-dicarboxypropyl)-ureido]pentanedioic acid (DUPA) was used as the targeting moiety to actively deliver DTX for treatment of Prostate-Specific Membrane Antigen (PSMA) expressing prostate cancer. Short and long spacer DUPA monomers were prepared, and four HPMA copolymer--DTX conjugates (non-targeted, two targeted with short spacer of different molecular weight and targeted with long spacer) were prepared via Reversible Addition-Fragmentation Chain Transfer (RAFT) copolymerization. Following confirmation of PSMA expression on C4-2 cell line, the DTX conjugates' in vitro cytotoxicity was tested against C4-2 tumor cells and their anticancer efficacies were assessed in nude mice bearing s.c. human prostate adenocarcinoma C4-2 xenografts. The in vivo results show that the spacer length between targeting moieties and HPMA copolymer backbone can significantly affect the treatment efficacy of DTX conjugates against C4-2 tumor bearing nu/nu mice. Moreover, histological analysis indicated that the DUPA-targeted DTX conjugate with longer spacer had no toxicity in major organs of treated mice.

  15. Characterization of Biomphalaria orbignyi, Biomphalaria peregrina and Biomphalaria oligoza by polymerase chain reaction and restriction enzyme digestion of the internal transcribed spacer region of the RNA ribosomal gene

    Directory of Open Access Journals (Sweden)

    Spatz Linus

    2000-01-01

    Full Text Available The correct identification of Biomphalaria oligoza, B. orbignyi and B. peregrina species is difficult due to the morphological similarities among them. B. peregrina is widely distributed in South America and is considered a potential intermediate host of Schistosoma mansoni. We have reported the use of the polymerase chain reaction and restriction fragment length polymorphism analysis of the internal transcribed spacer region of the ribosomal DNA for the molecular identification of these snails. The snails were obtained from different localities of Argentina, Brazil and Uruguay. The restriction patterns obtained with MvaI enzyme presented the best profile to identify the three species. The profiles obtained with all enzymes were used to estimate genetic similarities among B. oligoza, B. peregrina and B. orbignyi. This is also the first report of B. orbignyi in Uruguay.

  16. The evolutionary landscape of intergenic trans-splicing events in insects

    Science.gov (United States)

    Kong, Yimeng; Zhou, Hongxia; Yu, Yao; Chen, Longxian; Hao, Pei; Li, Xuan

    2015-01-01

    To explore the landscape of intergenic trans-splicing events and characterize their functions and evolutionary dynamics, we conduct a mega-data study of a phylogeny containing eight species across five orders of class Insecta, a model system spanning 400 million years of evolution. A total of 1,627 trans-splicing events involving 2,199 genes are identified, accounting for 1.58% of the total genes. Homology analysis reveals that mod(mdg4)-like trans-splicing is the only conserved event that is consistently observed in multiple species across two orders, which represents a unique case of functional diversification involving trans-splicing. Thus, evolutionarily its potential for generating proteins with novel function is not broadly utilized by insects. Furthermore, 146 non-mod trans-spliced transcripts are found to resemble canonical genes from different species. Trans-splicing preserving the function of ‘breakup' genes may serve as a general mechanism for relaxing the constraints on gene structure, with profound implications for the evolution of genes and genomes. PMID:26521696

  17. Benthic Bacterial Diversity in Submerged Sinkhole Ecosystems▿ †

    Science.gov (United States)

    Nold, Stephen C.; Pangborn, Joseph B.; Zajack, Heidi A.; Kendall, Scott T.; Rediske, Richard R.; Biddanda, Bopaiah A.

    2010-01-01

    Physicochemical characterization, automated ribosomal intergenic spacer analysis (ARISA) community profiling, and 16S rRNA gene sequencing approaches were used to study bacterial communities inhabiting submerged Lake Huron sinkholes inundated with hypoxic, sulfate-rich groundwater. Photosynthetic cyanobacterial mats on the sediment surface were dominated by Phormidium autumnale, while deeper, organically rich sediments contained diverse and active bacterial communities. PMID:19880643

  18. Multispacer sequence typing relapsing fever Borreliae in Africa.

    Directory of Open Access Journals (Sweden)

    Haitham Elbir

    Full Text Available BACKGROUND: In Africa, relapsing fevers are neglected arthropod-borne infections caused by closely related Borrelia species. They cause mild to deadly undifferentiated fever particularly severe in pregnant women. Lack of a tool to genotype these Borrelia organisms limits knowledge regarding their reservoirs and their epidemiology. METHODOLOGY/PRINCIPAL FINDINGS: Genome sequence analysis of Borrelia crocidurae, Borrelia duttonii and Borrelia recurrentis yielded 5 intergenic spacers scattered between 10 chromosomal genes that were incorporated into a multispacer sequence typing (MST approach. Sequencing these spacers directly from human blood specimens previously found to be infected by B. recurrentis (30 specimens, B. duttonii (17 specimens and B. crocidurae (13 specimens resolved these 60 strains and the 3 type strains into 13 species-specific spacer types in the presence of negative controls. B. crocidurae comprised of 8 spacer types, B. duttonii of 3 spacer types and B. recurrentis of 2 spacer types. CONCLUSIONS/SIGNIFICANCE: Phylogenetic analyses of MST data suggested that B. duttonii, B. crocidurae and B. recurrentis are variants of a unique ancestral Borrelia species. MST proved to be a suitable approach for identifying and genotyping relapsing fever borreliae in Africa. It could be applied to both vectors and clinical specimens.

  19. MO-AB-BRA-02: Modeling Nanoparticle-Eluting Spacer Degradation During Brachytherapy Application with in Situ Dose-Painting

    Energy Technology Data Exchange (ETDEWEB)

    Boateng, F [University of Massachusetts Lowell, Lowell, Massachusetts (United States); Ngwa, W [University of Massachusetts Lowell, Lowell, Massachusetts (United States); Harvard Medical School, Boston, MA (United States)

    2016-06-15

    Purpose: Brachytherapy application with in situ dose-painting using gold nanoparticles (GNP) released from GNP-loaded brachytherapy spacers has been proposed as an innovative approach to increase therapeutic efficacy during brachytherapy. This work investigates the dosimetric impact of slow versus burst release of GNP from next generation biodegradable spacers. Methods: Mathematical models were developed based on experimental data to study the release of GNP from a spacer designed with FDA approved poly(lactic-co-glycolic acid) (PLGA) polymer. The diffusion controlled released process and PLGA polymer degradation kinetics was incorporated in the calculations for the first time. An in vivo determined diffusion coefficient was used for determining the concentration profiles and corresponding dose enhancement based on initial GNP-loading concentrations of 7 mg/g. Results: The results showed that there is significant delay before the concentration profile of GNP diffusion in the tumor is similar to that when burst release is assumed as in previous studies. For example, in the case of burst release after spacer administration, it took up to 25 days for all the GNP to be released from the spacer using diffusion controlled release process only. However, it took up to 45 days when a combined model for both diffusion and polymer degradation processes was used. Based on the tumor concentration profiles, a significant dose enhancement factor (DEF >20%), could be attained at a tumor distances of 5 mm from a spacer loaded with 10 nm GNP sizes. Conclusion: The results highlight the need to take the slow release of GNP from spacers and factors such as biodegradation of polymers into account in research development of GNP-eluting spacers for brachytherapy applications with in-situ dose-painting using gold nanoparticles. The findings suggest that I-125 may be the more appropriate for such applications given the relatively longer half-live compared to other radioisotopes like Pd-103

  20. A numerical approach to the simulation of one-phase and two phase reactor coolant flow around nuclear fuel spacers

    International Nuclear Information System (INIS)

    Stosic, Z.V.; Stevanovic, V.D.

    2001-01-01

    A methodology for the simulation and analysis of one-phase and two-phase coolant flows around one or a row of spacers is presented. It is based on the multidimensional two-fluid mass, momentum and energy balance equations and application of adequate turbulence models. Necessary closure laws for interfacial transfer processes are presented. The stated general approach enables simulation and analyses of reactor coolant flow around spacers on different scale levels of the rod bundle geometry: detailed modelling of coolant flow around spacers and investigation of the influence of spacer's geometry on the coolant thermal-hydraulics, as well as prediction of global thermal-hydraulic parameters within the whole rod bundle with the investigation of the influence of rows of spacers on the bulk thermal-hydraulic processes. Sample problems are included illustrating these different modelling approaches. (author)

  1. Effect of different commercial feed spacers on biofouling of reverse osmosis membrane systems: A numerical study

    KAUST Repository

    Bucs, Szilard

    2014-06-01

    Feed spacers and hydrodynamics have been found relevant for the impact of biofouling on performance in reverse osmosis (RO) and nanofiltration (NF) membrane systems.The objectives of this study on biofouling development were to determine the impact of (i) linear flow velocity and bacterial cell load, (ii) biomass location and (iii) various feed spacer geometries as applied in practice as well as a modified geometry spacer.A three-dimensional mathematical model for biofouling of feed spacer channels including hydrodynamics, solute mass transport and biofilm formation was developed in COMSOL Multiphysics and MATLAB software.Results of this study indicate that the feed channel pressure drop increase caused by biofilm formation can be reduced by using thicker and/or modified feed spacer geometry and/or a lower flow rate in the feed channel. The increase of feed channel pressure drop by biomass accumulation is shown to be strongly influenced by the location of biomass. Results of numerical simulations are in satisfactory agreement with experimental data, indicating that this micro-scale mechanistic model is representative for practice. The developed model can help to understand better the biofouling process of spiral-wound RO and NF membrane systems and to develop strategies to reduce and control biofouling. © 2013 Elsevier B.V.

  2. Effect of different commercial feed spacers on biofouling of reverse osmosis membrane systems: A numerical study

    KAUST Repository

    Bucs, Szilard; Radu, Andrea I.; Lavric, Vasile; Vrouwenvelder, Johannes S.; Picioreanu, Cristian

    2014-01-01

    Feed spacers and hydrodynamics have been found relevant for the impact of biofouling on performance in reverse osmosis (RO) and nanofiltration (NF) membrane systems.The objectives of this study on biofouling development were to determine the impact of (i) linear flow velocity and bacterial cell load, (ii) biomass location and (iii) various feed spacer geometries as applied in practice as well as a modified geometry spacer.A three-dimensional mathematical model for biofouling of feed spacer channels including hydrodynamics, solute mass transport and biofilm formation was developed in COMSOL Multiphysics and MATLAB software.Results of this study indicate that the feed channel pressure drop increase caused by biofilm formation can be reduced by using thicker and/or modified feed spacer geometry and/or a lower flow rate in the feed channel. The increase of feed channel pressure drop by biomass accumulation is shown to be strongly influenced by the location of biomass. Results of numerical simulations are in satisfactory agreement with experimental data, indicating that this micro-scale mechanistic model is representative for practice. The developed model can help to understand better the biofouling process of spiral-wound RO and NF membrane systems and to develop strategies to reduce and control biofouling. © 2013 Elsevier B.V.

  3. Single-electron transistors fabricated with sidewall spacer patterning

    Science.gov (United States)

    Park, Byung-Gook; Kim, Dae Hwan; Kim, Kyung Rok; Song, Ki-Whan; Lee, Jong Duk

    2003-09-01

    We have implemented a sidewall spacer patterning method for novel dual-gate single-electron transistor (DGSET) and metal-oxide-semiconductor-based SET (MOSET) based on the uniform SOI wire, using conventional lithography and processing technology. A 30 nm wide silicon quantum wire is defined by a sidewall spacer patterning method, and depletion gates for two tunnel junctions of the DGSET are formed by the doped polycrystalline silicon sidewall. The fabricated DGSET and MOSET show clear single-electron tunneling phenomena at liquid nitrogen temperature and insensitivity of the Coulomb oscillation period to gate bias conditions. On the basis of the phase control capability of the sidewall depletion gates, we have proposed a complementary self-biasing method, which enables the SET/CMOS hybrid multi-valued logic (MVL) to operate perfectly well at high temperature, where the peak-to-valley current ratio of Coulomb oscillation severely decreases. The suggested scheme is evaluated by SPICE simulation with an analytical DGSET model, and it is confirmed that even DGSETs with a large Si island can be utilized efficiently in the multi-valued logic.

  4. Building a Plant DNA Barcode Reference Library for a Diverse Tropical Flora: An Example from Queensland, Australia

    Directory of Open Access Journals (Sweden)

    Craig M. Costion

    2016-02-01

    Full Text Available A foundation for a DNA barcode reference library for the tropical plants of Australia is presented here. A total of 1572 DNA barcode sequences are compiled from 848 tropical Queensland species. The dataset represents 35% of the total flora of Queensland’s Wet Tropics Bioregion, 57% of its tree species and 28% of the shrub species. For approximately half of the sampled species, we investigated the occurrence of infraspecific molecular variation in DNA barcode loci rbcLa, matK, and the trnH-psbA intergenic spacer region across previously recognized biogeographic barriers. We found preliminary support for the notion that DNA barcode reference libraries can be used as a tool for inferring biogeographic patterns at regional scales. It is expected that this dataset will find applications in taxonomic, ecological, and applied conservation research.

  5. Preliminary Investigation on Turbulent Flow in Tight-lattice Rod Bundle with Twist-mixing Vane Spacer Grid

    International Nuclear Information System (INIS)

    Lee, Chiyoung; Kwack, Youngkyun; Park, Juyong; Shin, Changhwan; In, Wangkee

    2013-01-01

    Our research group has investigated the effect of P/D difference on the behavior of turbulent rod bundle flow without the mixing vane spacer grid, using PIV (Particle Image Velocimetry) and MIR (Matching Index of Refraction) techniques for tight lattice fuel rod bundle application. In this work, using the tight-lattice rod bundle with a twist-mixing vane spacer grid, the turbulent rod bundle flow is preliminarily examined to validate the PIV measurement and CFD (Computational Fluid Dynamics) simulation. The turbulent flow in the tight-lattice rod bundle with a twist-mixing vane spacer grid was preliminarily examined to validate the PIV measurement and CFD simulation. Both were in agreement with each other within a reasonable degree of accuracy. Using PIV measurement and CFD simulation tested in this work, the detailed investigations on the behavior of turbulent rod bundle flow with the twist-mixing vane spacer grid will be performed at various conditions, and reported in the near future

  6. The Intergenic Recombinant HLA-B∗46:01 Has a Distinctive Peptidome that Includes KIR2DL3 Ligands

    Directory of Open Access Journals (Sweden)

    Hugo G. Hilton

    2017-05-01

    Full Text Available HLA-B∗46:01 was formed by an intergenic mini-conversion, between HLA-B∗15:01 and HLA-C∗01:02, in Southeast Asia during the last 50,000 years, and it has since become the most common HLA-B allele in the region. A functional effect of the mini-conversion was introduction of the C1 epitope into HLA-B∗46:01, making it an exceptional HLA-B allotype that is recognized by the C1-specific natural killer (NK cell receptor KIR2DL3. High-resolution mass spectrometry showed that HLA-B∗46:01 has a low-diversity peptidome that is distinct from those of its parents. A minority (21% of HLA-B∗46:01 peptides, with common C-terminal characteristics, form ligands for KIR2DL3. The HLA-B∗46:01 peptidome is predicted to be enriched for peptide antigens derived from Mycobacterium leprae. Overall, the results indicate that the distinctive peptidome and functions of HLA-B∗46:01 provide carriers with resistance to leprosy, which drove its rapid rise in frequency in Southeast Asia.

  7. WE-FG-BRA-02: Docetaxel Eluting Brachytherapy Spacers for Local Chemo-Radiation Therapy in Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Belz, J [Northeastern University, Boston, MA (United States); Kumar, R; Sridhar, S [Northeastern University & Dana Farber Cancer Institute, Boston, MA (United States); Makrigiorgos, G; Nguyen, P [Dana Farber Cancer Institute, Boston, MA (United States); D’Amico, A [Brigham & Women’s Hospital, Boston, MA (United States); Cormack, R [Harvard Medical School, Boston, MA (United States)

    2016-06-15

    Purpose: We propose an innovative combinatorial treatment strategy of Local ChemoRadiation Therapy (LCRT) using a sustained drug delivery platform in the form of a spacer to locally radio-sensitize the prostate with Docetaxel (DTX) enabling a synergistic cure with the use of lower radiation doses. These biodegradable spacers are physically similar to the inert spacers routinely used in prostate brachytherapy but are now loaded with formulations of DTX. Methods: Spacers were loaded with ∼500µg Docetaxel (DTX) for prostate cancer studies. The implants were characterized in vitro using SEM and HPLC. The release kinetic studies were carried out in buffer (pH 6.0) at 37°C. Subcutaneous PC3 tumors were xenografted in nude mice. Prostate cancer studies were done with and without radiation using SARRP at 5Gy, 10Gy, and 15Gy. Drug-loaded implants were injected once intratumorally using an 18G brachytherapy needle. Results: The release study in vitro showed a highly sustained release for multiple weeks at therapeutically relevant doses. The monotherapy with local DTX spacer showed sustained tumor inhibition compared to empty implants and an equivalent DTX dose given systemically. At 40 days, 89% survival was observed for mice treated with DTX implants compared with 0% in all other treatment groups. The combined treatment with local DTX spacer and radiation (10Gy) showed the highest degree of tumor suppression (significant tumor growth inhibition by day 90). The control mice showed continuous tumor growth and were scarified by day 56. Groups of mice treated with DTX-spacer or radiation alone showed initial tumor suppression but growth continued after day 60. A larger experiment is ongoing. Conclusion: This approach provides localized delivery of the chemotherapeutic sensitizer directly to the tumor and avoids the toxicities associated with both brachytherapy and current systemic delivery of docetaxel. Sustained release of DTX is an effective chemotherapy option alone or

  8. Spacer grid corner gusset

    International Nuclear Information System (INIS)

    Larson, J.G.

    1984-01-01

    There is provided a spacer grid for a bundle of longitudinally extending rods in spaced generally parallel relationship comprising spacing means for holding the rods in spaced generally parallel relationship; the spacing means includes at least one exterior grid strip circumscribing the bundle of rods along the periphery thereof; with at least one exterior grid strip having a first edge defining the boundary of the strip in one longitudinal direction and a second edge defining the boundary of the strip in the other longitudinal direction; with at least one exterior grid strip having at least one band formed therein parallel to the longitudinal direction; a plurality of corner gussets truncating each of a plurality of corners formed by at least one band and the first edge and the second edge

  9. Spacers for use in nuclear fuel assembly

    International Nuclear Information System (INIS)

    Shiohata, Hironori; Nakamura, Shozo; Hasegawa, Kunio; Higuchi, Shigeo; Nagashima, Hideaki; Kawada, Yoshishige.

    1987-01-01

    Purpose: To prevent liquid film breakage at the surface of a fuel rod due to swirlings of steam flow generated at the upstream of a contact portion between the fuel rod and a spacer leaf spring, that is, below the contact portion. Constitution: Steam-hot water 2-phase streams flowing from the lower to the upper portions of a fuel assembly is hindered by leaf springs, thereby forming swirlings in the steam flow at the upstream of a contact portion between the fuel rod and the leaf springs, that is, below the contact portion. The horseshoe-like swirlings shed the liquid films at the surface of the fuel rod to remarkably decrease the heat cooling performance, by which the surface temperature of a fuel can is temporarily increased thereby possibly causing failures due to so-called burnout in view of the above, steps are formed to the spacer leaf spring for use in the fuel assembly, to reduce the pressure difference between the leaf spring and the fuel rod at the upstream of the springs relative to the 2-phase coolant stream. In this way, formation of the swirlings is moderated to prevent the liquid film breakage and improve the critical heat power. (Kamimura, M.)

  10. An examination of the influence of spacers on burnout in an annulus cooled by the upflow of Freon-12

    International Nuclear Information System (INIS)

    Ilic, V.

    1975-04-01

    To evaluate the spacer influence on burnout, tests were carried out in Freon-12 at 1.04 MPa (abs.) test section inlet pressure with an internally heated annulus 2743 mm long by 14.4 mm heater diameter, the outer tube (shroud) having a bore of 22.1 mm. The inner rod (heater) was located centrally to the shroud by spacers and their configuration was changed for each test. Comparison of the results with those obtained with a test section having no spacers indicated that spacers can increase burnout power up to 75 per cent, decrease it, or show no effect at all, depending on the combination of the inlet temperature and mass velocity. If the spacers were streamlined, removed from the upstream portion of the heater or relocated farther upstream from the downstream end of the heater, there was a considerably reduced effect on the test section performance. (author)

  11. The use of ZnO as optical spacer in polymer solar cells : theoretical and experimental study

    NARCIS (Netherlands)

    Gilot, J.; Barbu, I.; Wienk, M.M.; Janssen, R.A.J.

    2007-01-01

    For org. solar cells, insertion of an optical spacer between the active layer and the reflective electrode results in a redistribution of the optical elec. field. In this paper, theor. calcns. using optical modeling are compared with exptl. results for devices with ZnO as optical spacer. An

  12. Development of an Efficient G-Quadruplex-Stabilised Thrombin-Binding Aptamer Containing a Three-Carbon Spacer Molecule

    DEFF Research Database (Denmark)

    Aaldering, Lukas J.; Poongavanam, Vasanthanathan; Langkjær, Niels

    2017-01-01

    The thrombin-binding aptamer (TBA), which shows anticoagulant properties, is one of the most studied G-quadruplex-forming aptamers. In this study, we investigated the impact of different chemical modifications such as a three-carbon spacer (spacer-C3), unlocked nucleic acid (UNA) and 3′-amino-mod...

  13. Investigation on effect of methylene spacer in holographic grating formation in eosin containing polymethacrylates

    Energy Technology Data Exchange (ETDEWEB)

    Manickasundaram, S. [Department of Chemistry, Anna University, Sardar Vallabai Patel Road, Chennai 600025 (India); Kannan, P. [Department of Chemistry, Anna University, Sardar Vallabai Patel Road, Chennai 600025 (India)]. E-mail: pakannan@annauniv.edu; Deepa, S. [Centre for Laser Technology, Department of Physics, Anna University, Chennai 600025 (India); Palanisamy, P.K. [Centre for Laser Technology, Department of Physics, Anna University, Chennai 600025 (India)

    2007-01-15

    A new series of eosin dye based poly(alkyloxymethacrylate)s was synthesized with an even number of side-chain methylene spacers by a free radical addition polymerization method for holographic optical data storage applications. These polymers were characterized by UV, IR and {sup 1}H NMR spectroscopy. The glass transition temperature and thermal stability of the polymers were investigated by DSC and TGA, respectively. As the spacer length increases in the side-chain, Tg, Tm and thermal stability of the polymers decrease, while a reverse trend was observed with film forming ability of the polymers. The optical characterization of the polymers was investigated by forming holographic grating using an Argon ion laser. The grating diffraction efficiency was found to depend not only on the concentration of polymeric film but also on the spacer length of the polymers.

  14. Investigation on effect of methylene spacer in holographic grating formation in eosin containing polymethacrylates

    International Nuclear Information System (INIS)

    Manickasundaram, S.; Kannan, P.; Deepa, S.; Palanisamy, P.K.

    2007-01-01

    A new series of eosin dye based poly(alkyloxymethacrylate)s was synthesized with an even number of side-chain methylene spacers by a free radical addition polymerization method for holographic optical data storage applications. These polymers were characterized by UV, IR and 1 H NMR spectroscopy. The glass transition temperature and thermal stability of the polymers were investigated by DSC and TGA, respectively. As the spacer length increases in the side-chain, Tg, Tm and thermal stability of the polymers decrease, while a reverse trend was observed with film forming ability of the polymers. The optical characterization of the polymers was investigated by forming holographic grating using an Argon ion laser. The grating diffraction efficiency was found to depend not only on the concentration of polymeric film but also on the spacer length of the polymers

  15. Interaction between zircaloy tube and inconel spacer grid at high temperature

    International Nuclear Information System (INIS)

    Nagase, Fumihisa; Otomo, Takashi; Uetsuka, Hiroshi; Furuta, Teruo

    1990-09-01

    In order to investigate the interaction between fuel cladding and spacer grid of the pressurized water reactor during a severe accident, isothermal reaction tests were performed at the temperature range from 1248 to 1673K. A specimen consisted of a short Zircaloy-4 cladding tube and a piece of spacer grid of Inconel-718. In the tests in an argon atmosphere, eutectic reaction between Zircaloy and Inconel was observed at the contact points at 1248K. Rapid reaction was observed at higher test temperatures. For example, in the test at 1373K for 300s, Zircaloy reacted with Inconel over the entire thickness (0.62mm) of the tube in the vicinity of the contact point. In the present tests, Zircaloy which has higher melting point than Inconel was dissolved preferentially due to eutectic formation. In the tests in an oxygen atmosphere, no eutectic reaction was observed at temperatures below 1437K. A trace of interaction was found at the contact point of specimen heated at 1573 and 1623K. However, decrease in Zircaloy thickness was not measured. The possibility of eutectic reaction between Zircaloy cladding and Inconel spacer grid seems to be quite limited when sufficient oxygen is supplied. (author)

  16. Numerical prediction on turbulent heat transfer of a spacer ribbed fuel rod for high temperature gas-cooled reactors

    International Nuclear Information System (INIS)

    Takase, Kazuyuki

    1994-11-01

    The turbulent heat transfer of a fuel rod with three-dimensional trapezoidal spacer ribs for high temperature gas-cooled reactors was analyzed numerically using the k-ε turbulence model, and investigated experimentally using a simulated fuel rod under the helium gas condition of a maximum outlet temperature of 1000degC and pressure of 4MPa. From the experimental results, it found that the turbulent heat transfer coefficients of the fuel rod were 18 to 80% higher than those of a concentric smooth annulus at a region of Reynolds number exceeding 2000. On the other hand, the predicted average Nusselt number of the fuel rod agreed well with the heat transfer correlation obtained from the experimental data within a relative error of 10% with Reynolds number of more than 5000. It was verified that the numerical analysis results had sufficient accuracy. Furthermore, the numerical prediction could clarify quantitatively the effects of the heat transfer augmentation by the spacer rib and the axial velocity increase due to a reduction in the annular channel cross-section. (author)

  17. [Cervical adaptation of complete cast crowns of various metal alloys, with and without die spacers].

    Science.gov (United States)

    Stephano, C B; Roselino, R F; Roselino, R B; Campos, G M

    1989-01-01

    A metallic replica from a dental preparation for crown was used to make 8 class-IV stone dies. The wax patterns for the casting of the crowns were obtained in two conditions: a) from the stone die with no spacer; and b) from the stone die with an acrylic spacer. Thus, 64 metallic crowns were casted, using 4 different alloys: DURACAST (Cu-Al), NICROCAST (Ni-Cr) and DURABOND (Ni-Cr), and gold. The casted crowns were fitted in the metallic replica and measured as to the cervical discrepance of fitting. The results showed that the use of die spacers decreases the clinical discrepancies of fitting of the casted crowns (in a statistically significant level), no matter the metallic alloy employed.

  18. Porosity of spacer-filled channels in spiral-wound membrane systems: Quantification methods and impact on hydraulic characterization

    KAUST Repository

    Siddiqui, Amber

    2017-04-13

    The porosity of spacer-filled feed channels influences the hydrodynamics of spiral-wound membrane systems and impacts the overall performance of the system. Therefore, an exact measurement and a detailed understanding of the impact of the feed channel porosity is required to understand and improve the hydrodynamics of spiral-wound membrane systems applied for desalination and wastewater reuse. The objectives of this study were to assess the accuracy of porosity measurement techniques for feed spacers differing in geometry and thickness and the consequences of using an inaccurate method on hydrodynamic predictions, which may affect permeate production. Six techniques were applied to measure the porosity namely, three volumetric calculations based on spacer strand count together with cuboidal (SC), cylindrical (VCC) and ellipsoidal volume calculation (VCE) and three independent techniques based on volume displacement (VD), weight and density (WD) and computed tomography scanning (CT). The CT method was introduced as an alternative for the other five already existing and applied methods in practice.Six feed spacers used for the porosity measurement differed in filament thickness, angle between the filaments and mesh-size. The results of the studies showed differences between the porosities, measured by the six methods. The results of the microscopic techniques SC, VCC and VCE deviated significantly from measurements by VD, WD and CT, which showed similar porosity values for all spacer types.Depending on the maximum deviation of the porosity measurement techniques from –6% to +6%, (i) the linear velocity deviations were −5.6% and +6.4% respectively and (ii) the pressure drop deviations were –31% and +43% respectively, illustrating the importance of an accurate porosity measurement. Because of the accuracy and standard deviation, the VD and WD method should be applied for the porosity determination of spacer-filled channels, while the CT method is recommended for

  19. Peri-Prosthetic Knee Infection Management: Spacers Loaded with Two or Three Antibiotic Agents.

    Science.gov (United States)

    Ortola, David Joaquin; Fenga, Domenico; Marcellino, Sandra; Rosi, Massimiliano; Centofanti, Francesco; Rosa, Michele Attilio

    2017-07-01

    The purpose of this work was to compare pre-made antibiotic-loaded spacers with two commercially available antibiotic agents and custom-made cements with three antibiotic agents added. We evaluated: (a) the validity of our procedures, (b) the control of the rate of infection in the long term, (c) complications, and (d) quality of life and patient satisfaction. A retrospective cohort study was performed on 112 consecutively treated patients between January 2010 and December 2013; 56 patients were treated with a pre-formed cement spacer (clindamycin + gentamicin), and 56 patients were treated with a spacer loaded with three antibiotic agents (clindamycin + gentamicin + vancomycin). Demographic data were collected: Classification of infection according to criteria of Cierny-Mader; microbiologic results; number of previous operations; and years of disease. Infection control or relapse after at least 18 months of follow-up was evaluated. Complications were recorded. Every patient completed the SF-36 test and Oxford Knee Score. With a follow-up of 32.87 months (standard deviation 12.04), at the end of treatment, amputation occurred in three of 112 patients because of recurrence of infection, and one patient died from other causes not related to the infection. The study population presented a rate of recurrence of infection of 2.70%. Our results suggest that a two stage re-implant with three antibiotic agents added to the spacer should be considered to avoid rescue procedures, especially in patients with multi-resistant micro-organism infections.

  20. Microbial Community Analysis of Field-Grown Soybeans with Different Nodulation Phenotypes▿

    OpenAIRE

    Ikeda, Seishi; Rallos, Lynn Esther E.; Okubo, Takashi; Eda, Shima; Inaba, Shoko; Mitsui, Hisayuki; Minamisawa, Kiwamu

    2008-01-01

    Microorganisms associated with the stems and roots of nonnodulated (Nod−), wild-type nodulated (Nod+), and hypernodulated (Nod++) soybeans [Glycine max (L.) Merril] were analyzed by ribosomal intergenic transcribed spacer analysis (RISA) and automated RISA (ARISA). RISA of stem samples detected no bands specific to the nodulation phenotype, whereas RISA of root samples revealed differential bands for the nodulation phenotypes. Pseudomonas fluorescens was exclusively associated with Nod+ soybe...

  1. Comparative study of the contribution of various PWR spacer grid components to hydrodynamic and wall pressure characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharjee, Saptarshi, E-mail: saptarshi.bhattacharjee@outlook.com [Alternative Energies and Atomic Energy Commission (CEA) – Cadarache, DEN/DTN/STCP/LHC, 13108 Saint Paul lez Durance Cedex (France); Laboratoire de Mécanique, Modélisation et Procédés Propres (M2P2), UMR7340 CNRS, Aix-Marseille Université, Centrale Marseille, 13451 Marseille Cedex (France); Ricciardi, Guillaume [Alternative Energies and Atomic Energy Commission (CEA) – Cadarache, DEN/DTN/STCP/LHC, 13108 Saint Paul lez Durance Cedex (France); Viazzo, Stéphane [Laboratoire de Mécanique, Modélisation et Procédés Propres (M2P2), UMR7340 CNRS, Aix-Marseille Université, Centrale Marseille, 13451 Marseille Cedex (France)

    2017-06-15

    Highlights: • Complex geometry inside a PWR fuel assembly is simulated using simplified 3D models. • Structured meshes are generated as far as possible. • Fluctuating hydrodynamic and wall pressure field are analyzed using LES. • Comparative studies between square spacer grid, circular spacer grid and mixing vanes are presented. • Simulations are compared with experimental data. - Abstract: Flow-induced vibrations in a pressurized water reactor (PWR) core can cause fretting wear in fuel rods. These vibrations can compromise safety of a nuclear reactor. So, it is necessary to know the random fluctuating forces acting on the rods which cause these vibrations. In this paper, simplified 3D models like square spacer grid, circular spacer grid and symmetric mixing vanes have been used inside an annular pipe. Hydrodynamic and wall pressure characteristics are evaluated using large eddy simulations (LES). Structured meshes are generated as far as possible. Simulations are compared with an experiment. Results show that the grid and vanes have a combined effect: grid accelerates the flow whereas the vanes contribute to the swirl structures. Spectral analysis of the simulations illustrate vortex shedding phenomenon in the wake of spacer grids. This initial study opens up interesting perspectives towards improving the modeling strategy and understanding the complex phenomenon inside a PWR core.

  2. Comparative study of the contribution of various PWR spacer grid components to hydrodynamic and wall pressure characteristics

    International Nuclear Information System (INIS)

    Bhattacharjee, Saptarshi; Ricciardi, Guillaume; Viazzo, Stéphane

    2017-01-01

    Highlights: • Complex geometry inside a PWR fuel assembly is simulated using simplified 3D models. • Structured meshes are generated as far as possible. • Fluctuating hydrodynamic and wall pressure field are analyzed using LES. • Comparative studies between square spacer grid, circular spacer grid and mixing vanes are presented. • Simulations are compared with experimental data. - Abstract: Flow-induced vibrations in a pressurized water reactor (PWR) core can cause fretting wear in fuel rods. These vibrations can compromise safety of a nuclear reactor. So, it is necessary to know the random fluctuating forces acting on the rods which cause these vibrations. In this paper, simplified 3D models like square spacer grid, circular spacer grid and symmetric mixing vanes have been used inside an annular pipe. Hydrodynamic and wall pressure characteristics are evaluated using large eddy simulations (LES). Structured meshes are generated as far as possible. Simulations are compared with an experiment. Results show that the grid and vanes have a combined effect: grid accelerates the flow whereas the vanes contribute to the swirl structures. Spectral analysis of the simulations illustrate vortex shedding phenomenon in the wake of spacer grids. This initial study opens up interesting perspectives towards improving the modeling strategy and understanding the complex phenomenon inside a PWR core.

  3. Measurement of droplet dynamics across grid spacer in mist cooling of subchannel of PWR

    International Nuclear Information System (INIS)

    Lee, S.L.; Sheen, H.J.; Cho, S.K.; Issapour, I.

    1984-01-01

    An experiment was conducted of the dynamics and heat transfer of a droplet-vapor mist flow across a test grid spacer in a flow channel of 2 x 2 electrically heated simulation fuel rods. Embedded thermocouples were used to measure the rod cladding temperature and an unshielded Chromel-Alumel thermocouple was transversed in the center of the subchannel to measure the temperature of the water and steam coolant phases at various axial locations. Thermocouples were also embedded in the test grid spacer. Optical measurements of the size and velocity distributions of droplets and the velocity distribution of the superheated steam were made by special laser-Doppler anemometry techniques through quartz glass windows immediately upstream and downstream of the test grid spacer. Experiments over a range of steam and injected water flow rates and rod heat flux have been performed and some representative results and discussions are presented

  4. Heterogeneous Diversity of Spacers within CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats)

    Science.gov (United States)

    He, Jiankui; Deem, Michael W.

    2010-09-01

    Clustered regularly interspaced short palindromic repeats (CRISPR) in bacterial and archaeal DNA have recently been shown to be a new type of antiviral immune system in these organisms. We here study the diversity of spacers in CRISPR under selective pressure. We propose a population dynamics model that explains the biological observation that the leader-proximal end of CRISPR is more diversified and the leader-distal end of CRISPR is more conserved. This result is shown to be in agreement with recent experiments. Our results show that the CRISPR spacer structure is influenced by and provides a record of the viral challenges that bacteria face.

  5. Response of an electrostatic probe for a right cylindrical spacer

    DEFF Research Database (Denmark)

    Rerup, T; Crichton, George C; McAllister, Iain Wilson

    1994-01-01

    During the last decade many experimental studies of surface charge phenomena have been undertaken employing right cylindrical spacers. Measurement of the surface charge was performed using small electrostatic field probes to scan across the dielectric surface. Charges are electrostatically induced...

  6. Enhanced current-perpendicular-to-plane giant magnetoresistance effect in half-metallic NiMnSb based nanojunctions with multiple Ag spacers

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Zhenchao; Yamamoto, Tatsuya [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Kubota, Takahide; Takanashi, Koki [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Center for Spintronics Research Network (CSRN), Tohoku University, Sendai 980-8577 (Japan)

    2016-06-06

    Current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) heterostructure devices using half-metallic NiMnSb Heusler alloy electrodes with single, dual, and triple Ag spacers were fabricated. The NiMnSb alloy films and Ag spacers show (001) epitaxial growth in all CPP-GMR multilayer structures. The dual-spacer CPP-GMR nanojunction exhibited an enhanced CPP-GMR ratio of 11% (a change in the resistance-area product, ΔRA, of 3.9 mΩ μm{sup 2}) at room temperature, which is approximately twice (thrice) of 6% (1.3 mΩ μm{sup 2}) in the single-spacer device. The enhancement of the CPP-GMR effects in the dual-spacer devices could be attributed to improved interfacial spin asymmetry. Moreover, it was observed that the CPP-GMR ratios increased monotonically as the temperatures decreased. At 4.2 K, a CPP-GMR ratio of 41% (ΔRA = 10.5 mΩ μm{sup 2}) was achieved in the dual-spacer CPP-GMR device. This work indicates that multispacer structures provide an efficient enhancement of CPP-GMR effects in half-metallic material-based CPP-GMR systems.

  7. Properties of promoters cloned randomly from the Saccharomyces cerevisiae genome.

    Science.gov (United States)

    Santangelo, G M; Tornow, J; McLaughlin, C S; Moldave, K

    1988-01-01

    Promoters were isolated at random from the genome of Saccharomyces cerevisiae by using a plasmid that contains a divergently arrayed pair of promoterless reporter genes. A comprehensive library was constructed by inserting random (DNase I-generated) fragments into the intergenic region upstream from the reporter genes. Simple in vivo assays for either reporter gene product (alcohol dehydrogenase or beta-galactosidase) allowed the rapid identification of promoters from among these random fragments. Poly(dA-dT) homopolymer tracts were present in three of five randomly cloned promoters. With two exceptions, each RNA start site detected was 40 to 100 base pairs downstream from a TATA element. All of the randomly cloned promoters were capable of activating reporter gene transcription bidirectionally. Interestingly, one of the promoter fragments originated in a region of the S. cerevisiae rDNA spacer; regulated divergent transcription (presumably by RNA polymerase II) initiated in the same region. Images PMID:2847031

  8. First detection of Rickettsia conorii ssp. caspia in Rhipicephalus sanguineus in Zambia.

    Science.gov (United States)

    Chitimia-Dobler, Lidia; Dobler, Gerhard; Schaper, Sabine; Küpper, Thomas; Kattner, Simone; Wölfel, Silke

    2017-11-01

    Ticks are important vectors for Rickettsia spp. of the spotted fever group all around the world. Rickettsia conorii is the etiological agent of boutonneuse fever in the Mediterranean region and Africa. Tick identification was based on morphological features and further characterized using the 16S rRNA gene. The ticks were individually tested using pan-Rickettsia real-time-PCR for screening, and 23S-5S intergenic spacer region, 16S rDNA, gltA, sca4, ompB, and ompA genes were used to analyze the Rickettsia positive samples. Rickettsia conorii ssp. caspia was detected in tick collected in Zambia for the first time, thus demonstrating the possibility of the occurrence of human disease, namely Astrakhan fever, due to this Rickettsia ssp. in this region of Africa. The prevalence of R. conorii ssp. caspia was 0.06% (one positive tick out of 1465 tested ticks) and 0.07% (one positive tick out of 1254 tested Rh. sanguineus).

  9. Nuclear reactor fuel assembly spacer grid

    International Nuclear Information System (INIS)

    Jabsen, F.S.

    1977-01-01

    A spacer grid for a nuclear fuel assembly is comprised of a lattice of grid plates forming multiple cells that are penetrated by fuel elements. Resilient protrusions and rigid protrusions projecting into the cells from the plates bear against the fuel element to effect proper support and spacing. Pairs of intersecting grid plates, disposed in a longitudinally spaced relationship, cooperate with other plates to form a lattice wherein each cell contains adjacent panels having resilient protrusions arranged opposite adjacent panels having rigid protrusions. The peripheral band bounding the lattice is provided solely with rigid protrusions projecting into the peripheral cells. (Auth.)

  10. Experimental investigations of the post-CHF heat transfer of R-134a flow-boiling in an annulus with spacer grids

    International Nuclear Information System (INIS)

    Lee, Kwi Lim; Chang, Soon Heung

    2009-01-01

    An experimental study was performed in the post-CHF condition using R-134a to investigate the effect of spacer grids on post-CHF heat transfer in an annulus channel. The experiments were conducted under the outlet pressures of 1.1 - 2.0 MPa, the mass fluxes of 100 - 400 kg/m 2 s and the inlet temperatures of 25 - 51degC. About 300 data of post-CHF data were obtained in the annular geometry without spacer grids and compared with several post-CHF correlations. The results showed the large prediction uncertainty mainly caused by the cold wall effect, so the empirical correlation for an annulus geometry without spacer grids was developed with the present experimental results. The heat transfer coefficient was calculated based on the heater rod temperature and the saturated vapor property. The average and root-mean-square(RMS) errors of the predictions were 0.17 % and 3.4 %, respectively. The experiments related to the spacer grid effects were performed with an I-type spacer grid and split-swirl mixing vane (with blockage-area ratios of 4.0 and 5.8 %). The spacer grid and mixing vane test results showed the enhancing effect on the heat transfer at the downstream location of the spacers. The experimental results from the spilt-swirl-type grid tests were more effective than the I-type grid tests. This was attributed to enhance the turbulence and increase the heat transfer caused by the mixing vane. (author)

  11. Priming in the Type I-F CRISPR-Cas system triggers strand-independent spacer acquisition, bi-directionally from the primed protospacer.

    Science.gov (United States)

    Richter, Corinna; Dy, Ron L; McKenzie, Rebecca E; Watson, Bridget N J; Taylor, Corinda; Chang, James T; McNeil, Matthew B; Staals, Raymond H J; Fineran, Peter C

    2014-07-01

    Clustered regularly interspaced short palindromic repeats (CRISPR), in combination with CRISPR associated (cas) genes, constitute CRISPR-Cas bacterial adaptive immune systems. To generate immunity, these systems acquire short sequences of nucleic acids from foreign invaders and incorporate these into their CRISPR arrays as spacers. This adaptation process is the least characterized step in CRISPR-Cas immunity. Here, we used Pectobacterium atrosepticum to investigate adaptation in Type I-F CRISPR-Cas systems. Pre-existing spacers that matched plasmids stimulated hyperactive primed acquisition and resulted in the incorporation of up to nine new spacers across all three native CRISPR arrays. Endogenous expression of the cas genes was sufficient, yet required, for priming. The new spacers inhibited conjugation and transformation, and interference was enhanced with increasing numbers of new spacers. We analyzed ∼ 350 new spacers acquired in priming events and identified a 5'-protospacer-GG-3' protospacer adjacent motif. In contrast to priming in Type I-E systems, new spacers matched either plasmid strand and a biased distribution, including clustering near the primed protospacer, suggested a bi-directional translocation model for the Cas1:Cas2-3 adaptation machinery. Taken together these results indicate priming adaptation occurs in different CRISPR-Cas systems, that it can be highly active in wild-type strains and that the underlying mechanisms vary. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

  12. Sub-15 nm nano-pattern generation by spacer width control for high density precisely positioned self-assembled device nanomanufacturing

    KAUST Repository

    Rojas, Jhonathan Prieto; Hussain, Muhammad Mustafa

    2012-01-01

    We present a conventional micro-fabrication based thin film vertical sidewall (spacer) width controlled nano-gap fabrication process to create arrays of nanopatterns for high density precisely positioned self-assembled nanoelectronics device integration. We have used conventional optical lithography to create base structures and then silicon nitride (Si 3N4) based spacer formation via reactive ion etching. Control of Si3N4 thickness provides accurate control of vertical sidewall (spacer) besides the base structures. Nano-gaps are fabricated between two adjacent spacers whereas the width of the gap depends on the gap between two adjacent base structures minus width of adjacent spacers. We demonstrate the process using a 32 nm node complementary metal oxide semiconductor (CMOS) platform to show its compatibility for very large scale heterogeneous integration of top-down and bottom-up fabrication as well as conventional and selfassembled nanodevices. This process opens up clear opportunity to overcome the decade long challenge of high density integration of self-assembled devices with precise position control. © 2012 IEEE.

  13. Sub-15 nm nano-pattern generation by spacer width control for high density precisely positioned self-assembled device nanomanufacturing

    KAUST Repository

    Rojas, Jhonathan Prieto

    2012-08-01

    We present a conventional micro-fabrication based thin film vertical sidewall (spacer) width controlled nano-gap fabrication process to create arrays of nanopatterns for high density precisely positioned self-assembled nanoelectronics device integration. We have used conventional optical lithography to create base structures and then silicon nitride (Si 3N4) based spacer formation via reactive ion etching. Control of Si3N4 thickness provides accurate control of vertical sidewall (spacer) besides the base structures. Nano-gaps are fabricated between two adjacent spacers whereas the width of the gap depends on the gap between two adjacent base structures minus width of adjacent spacers. We demonstrate the process using a 32 nm node complementary metal oxide semiconductor (CMOS) platform to show its compatibility for very large scale heterogeneous integration of top-down and bottom-up fabrication as well as conventional and selfassembled nanodevices. This process opens up clear opportunity to overcome the decade long challenge of high density integration of self-assembled devices with precise position control. © 2012 IEEE.

  14. Comparison of the Sequences of the Internal Transcribed Spacer Regions and PbGP43 Genes of Paracoccidioides brasiliensis from Patients and Armadillos (Dasypus novemcinctus)

    Science.gov (United States)

    Hebeler-Barbosa, Flavia; Morais, Flavia V.; Montenegro, Mario R.; Kuramae, Eiko E.; Montes, Beatriz; McEwen, Juan G.; Bagagli, Eduardo; Puccia, Rosana

    2003-01-01

    Paracoccidioides brasiliensis isolates from 10 nine-banded armadillos (Dasypus novemcinctus) were comparable with 19 clinical isolates by sequence analysis of the PbGP43 gene and ribosomal internal transcribed spacer 1 (ITS1) and ITS2 and by random amplified polymorphic DNA. In this original ITS study, eight isolates differed by one or three sites among five total substitution sites. PMID:14662970

  15. Experimental studies of the effect of functional spacers to annular flow in subchannels of a BWR fuel element

    Energy Technology Data Exchange (ETDEWEB)

    Damsohn, M., E-mail: damsohn@lke.mavt.ethz.c [ETH Zurich, Department of Mechanical and Process Engineering, Sonneggstrasse 3, 8092 Zuerich (Switzerland); Prasser, H.-M. [ETH Zurich, Department of Mechanical and Process Engineering, Sonneggstrasse 3, 8092 Zuerich (Switzerland)

    2010-10-15

    For the prediction of dryout in fuel elements of boiling water reactors, the dynamic behavior of the water film covering the fuel rod has to be understood. This paper provides high resolved experimental data of the liquid film and gives insight into the dynamic film behavior. The experiments of this work were conducted in a vertical channel representing a pair of neighboring subchannels of a BWR fuel rod bundle. Air and water at ambient pressure and temperature are used as model fluids, creating an annular flow in the test section. The influence of different functional spacer shapes on the liquid film has been studied. The heart of the instrumentation is a liquid film sensor (LFS), which measures the film thickness distribution around a half cylinder with a matrix of 64 x 16 measuring points with a time resolution of 10,000 frames per second and a spatial resolution of 2 mm x 2 mm. The high resolution allows for a visualization of the dynamic liquid film as a movie animation. Principals of the dynamic behavior of the liquid film are observed. The time-averaged film thickness distributions show that the spacers structure the liquid film significantly. The gaseous phase is accelerated due to the cross-section blockage caused by the spacer. This leads to a local thinning of the liquid film downstream of the spacer. Two statistical evaluation methods are presented to determine different dynamic wave properties: The wave velocity as function of the wave height, the traveling path of the waves and the location of wave separation and merge events. The first evaluation method shows that big waves move generally faster than small waves. The analysis further shows wave acceleration in close proximity of the spacer with subsequent deceleration further downstream. Analyzing the wave as a two-dimensional entity it can be seen that the wave paths are clearly structured by the spacer and hence do not travel circumferentially around the fuel rod. Wave separation and merge has a

  16. Experimental studies of the effect of functional spacers to annular flow in subchannels of a BWR fuel element

    International Nuclear Information System (INIS)

    Damsohn, M.; Prasser, H.-M.

    2010-01-01

    For the prediction of dryout in fuel elements of boiling water reactors, the dynamic behavior of the water film covering the fuel rod has to be understood. This paper provides high resolved experimental data of the liquid film and gives insight into the dynamic film behavior. The experiments of this work were conducted in a vertical channel representing a pair of neighboring subchannels of a BWR fuel rod bundle. Air and water at ambient pressure and temperature are used as model fluids, creating an annular flow in the test section. The influence of different functional spacer shapes on the liquid film has been studied. The heart of the instrumentation is a liquid film sensor (LFS), which measures the film thickness distribution around a half cylinder with a matrix of 64 x 16 measuring points with a time resolution of 10,000 frames per second and a spatial resolution of 2 mm x 2 mm. The high resolution allows for a visualization of the dynamic liquid film as a movie animation. Principals of the dynamic behavior of the liquid film are observed. The time-averaged film thickness distributions show that the spacers structure the liquid film significantly. The gaseous phase is accelerated due to the cross-section blockage caused by the spacer. This leads to a local thinning of the liquid film downstream of the spacer. Two statistical evaluation methods are presented to determine different dynamic wave properties: The wave velocity as function of the wave height, the traveling path of the waves and the location of wave separation and merge events. The first evaluation method shows that big waves move generally faster than small waves. The analysis further shows wave acceleration in close proximity of the spacer with subsequent deceleration further downstream. Analyzing the wave as a two-dimensional entity it can be seen that the wave paths are clearly structured by the spacer and hence do not travel circumferentially around the fuel rod. Wave separation and merge has a

  17. Effect of spacer grid mixing vanes on coolant outlet temperature distribution

    Energy Technology Data Exchange (ETDEWEB)

    Raemae, Tommi; Lahtinen, Tuukka; Brandt, Tellervo; Toppila, Timo [Fortum Power and Heat, Fortum (Finland). Nuclear Competence Center

    2012-08-15

    In Loviisa VVER-440-type NPP the coolant outlet temperature of the hot subchannel is constantly monitored during the operation. According to the authority requirement the maximum subchannel outlet temperature must not exceed the saturation temperature. Coolant temperature distribution inside the fuel assembly is affected by the efficiency of the coolant mixing. In order to enhance the coolant mixing the fuel manufacturer is introducing the additional mixing vanes on the fuel bundle spacer grids. In the paper the effect of the different mixing vane modifications is studied with computational fluid dynamics (CFD) simulation. Goal of the modelling is to find vane modifications with which sufficient mixing is reached with acceptable increase in the spacer grid pressure loss. The results of the studies are discussed in the paper. (orig.)

  18. Spacer geometry and particle deposition in spiral wound membrane feed channels

    KAUST Repository

    Radu, A.I.; van Steen, M.S.H.; Vrouwenvelder, Johannes S.; van Loosdrecht, Mark C.M.; Picioreanu, C.

    2014-01-01

    Deposition of microspheres mimicking bacterial cells was studied experimentally and with a numerical model in feed spacer membrane channels, as used in spiral wound nanofiltration (NF) and reverse osmosis (RO) membrane systems. In-situ microscopic

  19. Device for a nuclear reactor. [Fuel element spacers

    Energy Technology Data Exchange (ETDEWEB)

    Foulds, R B; Kasberg, A H; Puechl, K H; Bleiberg, M L

    1972-03-08

    A spacer design for fuel element clusters for PWR type reactors is described. It consists of a frame supporting an egg-carton like grid each sector of which is provided with springs which grip the fuel pins. The spring design is such as to prevent fuel pin vibrations and at same time accommodate fuel pin deformations. Formulae for the calculation of natural frequencies, spring stiffness and friction loads are presented.

  20. Lactic acid bacteria from chicken carcasses with inhibitory activity against Salmonella spp. and Listeria monocytogenes.

    Science.gov (United States)

    Sakaridis, I; Soultos, N; Dovas, C I; Papavergou, E; Ambrosiadis, I; Koidis, P

    2012-02-01

    This study was conducted to isolate psychrotrophic lactic acid bacteria (LAB) from chicken carcasses with inhibitory activity against strains of Salmonella spp. and Listeria monocytogenes. A total of 100 broiler samples were examined for the presence of LAB. Ninety-two LAB isolates that showed antimicrobial effects against Salmonella spp. and L. monocytogenes were further analysed to examine their LAB (Gram-positive, catalase negative, oxidase negative) and psychrotrophic characteristics (ability to grow at 7 °C). Fifty isolates were further selected and identified initially using standard biochemical tests in miniature (Micro-kits API CH 50) and then by sequencing of the 16s-23s rRNA gene boundary region (Intergenic Spacer Region). By molecular identification, these isolates were classified into 5 different LAB species: Lactobacillus salivarius, Lactobacillus reuteri, Lactobacillus johnsonii, Pediococcus acidilactici, and Lactobacillus paralimentarius. None of the isolates produced tyramine or histamine. Copyright © 2011 Elsevier Ltd. All rights reserved.

  1. Genomic Variability of Haemophilus influenzae Isolated from Mexican Children Determined by Using Enterobacterial Repetitive Intergenic Consensus Sequences and PCR

    OpenAIRE

    Gomez-De-Leon, Patricia; Santos, Jose I.; Caballero, Javier; Gomez, Demostenes; Espinosa, Luz E.; Moreno, Isabel; Piñero, Daniel; Cravioto, Alejandro

    2000-01-01

    Genomic fingerprints from 92 capsulated and noncapsulated strains of Haemophilus influenzae from Mexican children with different diseases and healthy carriers were generated by PCR using the enterobacterial repetitive intergenic consensus (ERIC) sequences. A cluster analysis by the unweighted pair-group method with arithmetic averages based on the overall similarity as estimated from the characteristics of the genomic fingerprints, was conducted to group the strains. A total of 69 fingerprint...

  2. Experimental and numerical characterization of the water flow in spacer-filled channels of spiral-wound membranes

    KAUST Repository

    Bucs, Szilard

    2015-09-25

    Micro-scale flow distribution in spacer-filled flow channels of spiral-wound membrane modules was determined with a particle image velocimetry system (PIV), aiming to elucidate the flow behaviour in spacer-filled flow channels. Two-dimensional water velocity fields were measured in a flow cell (representing the feed spacer-filled flow channel of a spiral wound reverse osmosis membrane module without permeate production) at several planes throughout the channel height. At linear flow velocities (volumetric flow rate per cross-section of the flow channel considering the channel porosity, also described as crossflow velocities) used in practice (0.074 and 0.163 m∙s-1) the recorded flow was laminar with only slight unsteadiness in the upper velocity limit. At higher linear flow velocity (0.3 m∙s-1) the flow was observed to be unsteady and with recirculation zones. Measurements made at different locations in the flow cell exhibited very similar flow patterns within all feed spacer mesh elements, thus revealing the same hydrodynamic conditions along the length of the flow channel. Three-dimensional (3-D) computational fluid dynamics simulations were performed using the same geometries and flow parameters as the experiments, based on steady laminar flow assumption. The numerical results were in good agreement (0.85-0.95 Bray-Curtis similarity) with the measured flow fields at linear velocities of 0.074 and 0.163 m∙s-1, thus supporting the use of model-based studies in the optimization of feed spacer geometries and operational conditions of spiral wound membrane systems.

  3. Experimental and numerical characterization of the water flow in spacer-filled channels of spiral-wound membranes.

    Science.gov (United States)

    Bucs, Szilard S; Linares, Rodrigo Valladares; Marston, Jeremy O; Radu, Andrea I; Vrouwenvelder, Johannes S; Picioreanu, Cristian

    2015-12-15

    Micro-scale flow distribution in spacer-filled flow channels of spiral-wound membrane modules was determined with a particle image velocimetry system (PIV), aiming to elucidate the flow behaviour in spacer-filled flow channels. Two-dimensional water velocity fields were measured in a flow cell (representing the feed spacer-filled flow channel of a spiral wound reverse osmosis membrane module without permeate production) at several planes throughout the channel height. At linear flow velocities (volumetric flow rate per cross-section of the flow channel considering the channel porosity, also described as crossflow velocities) used in practice (0.074 and 0.163 m·s(-1)) the recorded flow was laminar with only slight unsteadiness in the upper velocity limit. At higher linear flow velocity (0.3 m·s(-1)) the flow was observed to be unsteady and with recirculation zones. Measurements made at different locations in the flow cell exhibited very similar flow patterns within all feed spacer mesh elements, thus revealing the same hydrodynamic conditions along the length of the flow channel. Three-dimensional (3-D) computational fluid dynamics simulations were performed using the same geometries and flow parameters as the experiments, based on steady laminar flow assumption. The numerical results were in good agreement (0.85-0.95 Bray-Curtis similarity) with the measured flow fields at linear velocities of 0.074 and 0.163 m·s(-1), thus supporting the use of model-based studies in the optimization of feed spacer geometries and operational conditions of spiral wound membrane systems. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Knowledge of spacer device, peak flow meter and inhaler technique ...

    African Journals Online (AJOL)

    Background: Metered dose inhalers are cornerstone in effective management of bronchial asthma when correctly used. Most studies hitherto have focused on assessing patient's knowledge of inhaler technique. We sought to assess the knowledge of inhaler technique, spacer device and peak flow meter among doctors and ...

  5. Enhancement of nuclear heat transfer in a typical pressurized water reactor by new spacer grids

    International Nuclear Information System (INIS)

    Nazifi, M.; Nematollahi, M.

    2007-01-01

    The fuel element geometry typically used in nuclear reactor is rod bundle whose rod-to-rod clearance is maintained by grid spacer. The heat generated in the rod by nuclear reaction is removed by coolant, usually in turbulent flow. The coolant moves axially through the subchannels. Fuel spacer grid affects the coolant flow distribution in a fuel rod bundle, and so spacer geometry has a strong influence on a bundle's thermal-hydraulic characteristics such as critical heat flux and pressure drop. An understanding of the detailed structure of the turbulent flow and heat transfer in the rod bundle, used especially as nuclear fuel elements, is of major interest to the nuclear power industry for their safe and reliable operation. The flow mixing devices on grid spacer would enhance the mixing rate between sub-channels and promote the turbulence in subchannel. The present study evaluates the effects of mixing vane shape on flow structure and heat transfer downstream of mixing vane in a sub-channel of fuel assembly, by obtaining velocity and pressure fields, turbulent intensity, flow mixing factors, heat transfer coefficient and friction factor using three-dimensional RANS analysis. Six new shapes mixing vane designed by the authors, are simulated numerically to evaluate the performance in enhancing the heat transfer, in comparison with commercialized split vane. Standard K-epsilon model are used as a turbulence closure model and periodic and symmetry condition are set as boundary conditions. The capability of the model to predict the coolant flow distribution inside rod bundles is shown and discussed on the base of comparison with experimental data for a variety of geometrical and Reynolds number conditions. It is conformed that the turbulence in the sub-channel was significantly promoted by spacer and mixing devices but rapidly decreased to a fully developed level approximately 10 time of hydraulic diameter downstream of the top of spacer. Ring type mixer showed a high

  6. Influence of spacer length on heparin coupling efficiency and fibrinogen adsorption of modified titanium surfaces

    Directory of Open Access Journals (Sweden)

    Gbureck Uwe

    2007-07-01

    Full Text Available Abstract Background Chemical bonding of the drug onto surfaces by means of spacer molecules is accompanied with a reduction of the biological activity of the drug due to a constricted mobility since normally only short spacer molecule like aminopropyltrimethoxysilane (APMS are used for drug coupling. This work aimed to study covalent attachment of heparin to titanium(oxide surfaces by varying the length of the silane coupling agent, which should affect the biological potency of the drug due to a higher mobility with longer spacer chains. Methods Covalent attachment of heparin to titanium metal and TiO2 powder was carried out using the coupling agents 3-(Trimethoxysilyl-propylamine (APMS, N- [3-(Trimethoxysilylpropyl]ethylenediamine (Diamino-APMS and N1- [3-(Trimethoxy-silyl-propyl]diethylenetriamine (Triamino-APMS. The amount of bound coupling agent and heparin was quantified photometrically by the ninhydrin reaction and the tolidine-blue test. The biological potency of heparin was determined photometrically by the chromogenic substrate Chromozym TH and fibrinogen adsorption to the modified surfaces was researched using the QCM-D (Quartz Crystal Microbalance with Dissipation Monitoring technique. Results Zeta-potential measurements confirmed the successful coupling reaction; the potential of the unmodified anatase surface (approx. -26 mV shifted into the positive range (> + 40 mV after silanisation. Binding of heparin results in a strongly negatively charged surface with zeta-potentials of approx. -39 mV. The retaining biological activity of heparin was highest for the spacer molecule Triamino-APMS. QCM-D measurements showed a lower viscosity for adsorbed fibrinogen films on heparinised surfaces by means of Triamino-APMS. Conclusion The remaining activity of heparin was found to be highest for the covalent attachment with Triamino-APMS as coupling agent due to the long chain of this spacer molecule and therefore the highest mobility of the drug

  7. Biogeography of Deep-sea benthic bacteria at regional scale (LTER HAUSGARTEN, Fram Strait, Arctic.

    Directory of Open Access Journals (Sweden)

    Marianne Jacob

    Full Text Available Knowledge on spatial scales of the distribution of deep-sea life is still sparse, but highly relevant to the understanding of dispersal, habitat ranges and ecological processes. We examined regional spatial distribution patterns of the benthic bacterial community and covarying environmental parameters such as water depth, biomass and energy availability at the Arctic Long-Term Ecological Research (LTER site HAUSGARTEN (Eastern Fram Strait. Samples from 13 stations were retrieved from a bathymetric (1,284-3,535 m water depth, 54 km in length and a latitudinal transect (∼ 2,500 m water depth; 123 km in length. 454 massively parallel tag sequencing (MPTS and automated ribosomal intergenic spacer analysis (ARISA were combined to describe both abundant and rare types shaping the bacterial community. This spatial sampling scheme allowed detection of up to 99% of the estimated richness on phylum and class levels. At the resolution of operational taxonomic units (97% sequence identity; OTU3% only 36% of the Chao1 estimated richness was recovered, indicating a high diversity, mostly due to rare types (62% of all OTU3%. Accordingly, a high turnover of the bacterial community was also observed between any two sampling stations (average replacement of 79% of OTU3%, yet no direct correlation with spatial distance was observed within the region. Bacterial community composition and structure differed significantly with increasing water depth along the bathymetric transect. The relative sequence abundance of Verrucomicrobia and Planctomycetes decreased significantly with water depth, and that of Deferribacteres increased. Energy availability, estimated from phytodetrital pigment concentrations in the sediments, partly explained the variation in community structure. Overall, this study indicates a high proportion of unique bacterial types on relatively small spatial scales (tens of kilometers, and supports the sampling design of the LTER site HAUSGARTEN to

  8. Staged Custom, Intramedullary Antibiotic Spacers for Severe Segmental Bone Loss in Infected Total Hip Arthroplasty

    Directory of Open Access Journals (Sweden)

    Atul F. Kamath

    2011-01-01

    Full Text Available Introduction. Total hip arthroplasty (THA infections with severe bone loss pose significant reconstructive challenges. We present our experience with two-stage hip reimplantation using an intramedullary, antibiotic-impregnated nail. Methods. Three patients with infected THA with severe proximal femoral bone loss (Mallory type IIIB or greater were treated using a custom antibiotic spacer. Clinical outcomes and any complications were recorded. Average followup was 49 months from final reimplantation. Results. Mean age at spacer placement (stage 1 was 53 years. The mean Harris Hip Score at final followup was 80. Two patients had asymptomatic heterotopic ossification, and one patient had a 2 cm leg-length discrepancy. Conclusions. A custom intramedullary nail antibiotic spacer is a reliable option in the staged management of the infected THA with severe proximal femoral bone loss. Benefits of this technique include limb salvage with maintenance of leg length, soft tissue tension, and functional status.

  9. Measurement of grid spacer's enhanced droplet cooling under reflood condition in a PWR by LDA

    International Nuclear Information System (INIS)

    Lee, S.L.; Sheen, H.J.; Cho, S.K.; Issapour, I.; Hua, S.Q.

    1984-01-01

    Reported is an experiment designed for the measurements of grid spacer's enhanced droplet cooling under reflood condition at elevated temperatures in a steam environment. The flow channel consists of a simulated 1.60m-long pressurized water reactor (PWR) fuel rod bundle of 2 x 2 electrically heated rods. Embedded thermocouples are used to measure the rod cladding temperature at various axial levels and an unshielded Chromel-Alumel thermocouple sheathed by a small Inconel tube is traversed in the center of the subchannel to measure the temperatures of the water and steam coolant phases at various levels. The droplet dynamics across the grid spacer is directly obtained by a special laser-Doppler anemometry technique for the in situ simultaneous measurement of velocity and size of droplets through two observation windows on the test channel, one immediately before and one immediately after the grid spacer. Some results are presented and analyzed

  10. A Facile Technique to Make Articulating Spacers for Infected Total Knee Arthroplasty

    Directory of Open Access Journals (Sweden)

    Yu-Ping Su

    2009-03-01

    Conclusion: Treating infected total knee arthroplasty with these self-made articulating spacers eradicates infection effectively, improves the life quality before reimplantation and provides good final results without significant complications.

  11. Spacer stability and prostate position variability during radiotherapy for prostate cancer applying a hydrogel to protect the rectal wall

    International Nuclear Information System (INIS)

    Pinkawa, Michael; Piroth, Marc D.; Holy, Richard; Escobar-Corral, Nuria; Caffaro, Mariana; Djukic, Victoria; Klotz, Jens; Eble, Michael J.

    2013-01-01

    Background and purpose: The aim was to evaluate the spacer dimensions and prostate position variability during the course of radiotherapy for prostate cancer. Materials and methods: CT scans were performed in a group of 15 patients (G1) after the 10 ml injection of a hydrogel spacer (SpaceOAR™) and 30 patients without a spacer (G2) before the beginning of treatment (CT1) and in the last treatment week, 10–12 weeks following spacer implantation (CT2). Spacer dimensions and displacements were determined and prostate displacements compared. Results: Mean volume of the hydrogel increased slightly (17%; p 2 cm 3 . The average displacement of the hydrogel center of mass was 0.6 mm (87% ⩽ 2.2 mm), −0.6 mm (100% ⩽ 2.2 mm) and 1.4 mm (87% ⩽ 4.3 mm) in the x-, y- and z-axes (not significant). The average distance between prostate and anterior rectal wall before/at the end of radiotherapy was 1.6 cm/1.5 cm, 1.2 cm/1.3 cm and 1.0 cm/1.1 cm at the level of the base, middle and apex (G1). Prostate position variations were similar comparing G1 and G2, but significant systematic posterior displacements were only found in G2. Conclusions: A stable distance between the prostate and anterior rectal wall results during the radiotherapy course after injection of the spacer before treatment planning. Larger posterior prostate displacements could be reduced

  12. Predicting the impact of feed spacer modification on biofouling by hydraulic characterization and biofouling studies in membrane fouling simulators

    KAUST Repository

    Siddiqui, Amber; Lehmann, S.; Bucs, Szilard; Fresquet, M.; Fel, L.; Prest, E.I.E.C.; Ogier, J.; Schellenberg, C.; van Loosdrecht, M.C.M.; Kruithof, J.C.; Vrouwenvelder, Johannes S.

    2016-01-01

    Feed spacers are an essential part of spiral-wound reverse osmosis (RO) and nanofiltration (NF) membrane modules. Geometric modification of feed spacers is a potential option to reduce the impact of biofouling on the performance of membrane systems

  13. Visible light dynamical diffraction in a 1-D photonic crystal-based interferometer with an extremely thin spacer layer

    International Nuclear Information System (INIS)

    Prudnikov, I.R.

    2016-01-01

    Properties of light diffraction in a Fabry–Pérot-like interferometer composed of two 1-D photonic crystals and a nanometer-thick spacer layer are analytically investigated. It is shown that the resonant enhancement of light wave intensity in such a layer is possible because of light dynamical diffraction from the photonic crystals of the interferometer. Numerical simulations of (i) light reflectivity and transmittance curves of the interferometer having an ultra-thin spacer layer (its thickness changes from less than 1 nm to about 10 nm) and (ii) the resonant distribution of the light wave intensity in the vicinity of the layer are performed. Based on the numerical simulations, potentialities for the determination of the structural parameters (e.g., thicknesses and refraction indexes) of ultra-thin spacer films are discussed. A difference is found to appear in resonant intensity enhancements inside the ultra-thin spacer layers between s- and p-polarized light waves.

  14. Eddy current detection of spacers in the fuel channels of CANDU nuclear reactors

    International Nuclear Information System (INIS)

    Krause, T.W.; Schankula, J.; Sullivan, S.P.

    2002-01-01

    Garter Spring (GS) spacers in the fuel channels of CANDU nuclear reactors maintain separation between the hot pressure tube and surrounding moderator cooled calandria tube. Eddy current detection of the four GSs provides assurance that spacers are at or close to design positions and are performing their intended function of maintaining a non-zero gap between pressure tube and calandria tube. Pressure tube constrictions, resulting from relatively less diametral creep at end-of-fuel bundle locations, also produce large eddy current signals. Large constrictions, present in higher service pressure tubes, can produce signals that are 10 times larger than GS signals, reducing GS detectability to 30% in standard GS-detect probes. The introduction of field-focussing elements into the design of the standard GS detection eddy current probe has been used to recover the detectability of GS spacers by increasing the signal amplitude obtained from GSs relative to that from constrictions by a factor of 10. The work presented here compares laboratory, modelling and in-reactor measurements of GS and constriction signals obtained from the standard probe with that obtained from field-focussed eddy current probe designs. (author)

  15. Diagnosis of Persistent Infection in Prosthetic Two-Stage Exchange: Evaluation of the Effect of Sonication on Antibiotic Release from Bone Cement Spacers.

    Science.gov (United States)

    Mariaux, Sandrine; Furustrand Tafin, Ulrika; Borens, Olivier

    2018-01-01

    Introduction : When treating periprosthetic joint infection with a two-stage procedure, antibiotic-impregnated spacers can be used in the interval between prosthetic removal and reimplantation. In our experience, cultures of sonicated spacers are most often negative. The objective of the study was to assess whether that sonication causes an elution of antibiotics, leading to elevated antibiotic concentrations in the sonication fluid inhibiting bacterial growth and thus causing false-negative cultures. Methods : A prospective monocentric study was performed from September 2014 to March 2016. Inclusion criteria were a two-stage procedure for prosthetic infection and agreement of the patient to participate in the study. Spacers were made of gentamicin-containing cement to which tobramycin and vancomycin were added. Antibiotic concentrations in the sonication fluid were determined by mass-spectometry (LC-MS). Results : 30 patients were identified (15 hip and 14 knee and 1 ankle arthroplasties). No cases of culture positive sonicated spacer fluid were observed in our serie. In the sonication fluid median concentrations of 13.2µg/ml, 392 µg/ml and 16.6 µg/ml were detected for vancomycin, tobramycin and gentamicin, respectively. According to the European Committee on antimicrobial susceptibility testing (EUCAST), these concentrations released from cement spacer during sonication are higher than the minimal inhibitory concentrations (MICs) for most bacteria relevant in prosthetic joint infections. Conclusion: Spacer sonication cultures remained sterile in all of our cases. Elevated concentrations of antibiotics released during sonication could explain partly negative-cultured sonicated spacers. Indeed, the absence of antibiotic free interval during the two-stages can also contribute to false-negative spacers sonicated cultures.

  16. INTERNAL TRANSCRIBED SPACER (ITS), AN IDEAL DNA BARCODE FOR SPECIES DISCRIMINATION IN CRAWFURDIA WALL. (GENTIANACEAE).

    Science.gov (United States)

    Zhang, Dequan; Jiang, Bei; Duan, Lizhen; Zhou, Nong

    2016-01-01

    DNA barcoding is a technique used to identify species based on species-specific differences in short regions of their DNA. It is widely used in species discrimination of medicinal plants and traditional medicines. In the present study, four potential DNA barcodes, namely rbcL , matK , trnH-psbA and ITS (nuclear ribosomal internal transcribed spacer) were adopted for species discrimination in Crawfurdia Wall (Genetiaceae). Identification ability of these DNA barcodes and combinations were evaluated using three classic methods (Distance, Blast and Tree-Building). As a result, ITS, trnH-psbA and rbcL regions showed great universality for a success rate of 100%; whereas matK was disappointing for which only 65% samples gained useful DNA sequences. ITS region, which could clearly and effectively identify the five species in Crawfurdia , performed very well in this study. On the contrary, trnH-psbA and rbcL performed poorly in discrimination among these species. ITS marker was an ideal DNA barcode in Crawfurdia and it should be incorporated into one of the core barcodes for seed plants.

  17. Rapid Acquisition of Linezolid Resistance in Methicillin-Resistant Staphylococcus aureus: Role of Hypermutation and Homologous Recombination.

    Science.gov (United States)

    Iguchi, Shigekazu; Mizutani, Tomonori; Hiramatsu, Keiichi; Kikuchi, Ken

    2016-01-01

    We previously reported the case of a 64-year-old man with mediastinitis caused by Staphylococcus aureus in which the infecting bacterium acquired linezolid resistance after only 14 days treatment with linezolid. We therefore investigated relevant clinical isolates for possible mechanisms of this rapid acquisition of linezolid resistance. Using clinical S. aureus isolates, we assessed the in vitro mutation rate and performed stepwise selection for linezolid resistance. To investigate homologous recombination, sequences were determined for each of the 23S ribosomal RNA (23S rRNA) loci; analyzed sequences spanned the entirety of each 23S rRNA gene, including domain V, as well as the 16S-23S intergenic spacer regions. We additionally performed next-generation sequencing on clinical strains to identify single-nucleotide polymorphisms compared to the N315 genome. Strains isolated from the patient prior to linezolid exposure (M5-M7) showed higher-level linezolid resistance than N315, and the pre-exposure strain (M2) exhibited more rapid acquisition of linezolid resistance than did N315. However, the mutation rates of these and contemporaneous clinical isolates were similar to those of N315, and the isolates did not exhibit any mutations in hypermutation-related genes. Sequences of the 23S rRNA genes and 16S-23S intergenic spacer regions were identical among the pre- and post-exposure clinical strains. Notably, all of the pre-exposure isolates harbored a recQ missense mutation (Glu69Asp) with respect to N315; such a lesion may have affected short sequence recombination (facilitating, for example, recombination among rrn loci). We hypothesize that this mechanism contributed to rapid acquisition of linezolid resistance. Hypermutation and homologous recombination of the ribosomal RNA genes, including 23S rRNA genes, appear not to have been sources of the accelerated acquisition of linezolid resistance observed in our clinical case. Increased frequency of short sequence

  18. Time spans and spacers: Molecular phylogenetic explorations in the Cladophora complex (Chlorophyta) from the perspective of rDNA gene and spacer sequences

    OpenAIRE

    Bakker, Frederik Theodoor

    1995-01-01

    In this study, phylogenetic relationships among genera, species and biogeographic representatives of single Cladophora species within the Cladophorales were analyzed using rDNA gene and spacer sequences. Based on phylogenetic analysis of 18S rRNA gene sequences, the Cladophora complex is shown to be paraphyletic with respect to Cladophora species and includes several genera shich werde traditionally ascribed to the Siphonocladales (Chapter 3). ... Zie: Summary/Samenvatting

  19. Aerosol delivery from spacers in wheezy infants: a daily life study

    NARCIS (Netherlands)

    H.M. Janssens (Hettie); E.M. Heijnen; V.M. de Jong; W.C.J. Hop (Wim); W.P. Holland (Wim); J.C. de Jongste (Johan); H.A.W.M. Tiddens (Harm)

    2000-01-01

    textabstractThe aims of this study were to assess and compare dose delivery and dose variability of pressurized metered dose inhalers (pMDI)/spacers in wheezy infants in daily life and to investigate factors influencing aerosol delivery. In an open randomized

  20. Intensity Modulated Proton and Photon Therapy for Early Prostate Cancer With or Without Transperineal Injection of a Polyethylen Glycol Spacer: A Treatment Planning Comparison Study

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Damien C., E-mail: damien.weber@unige.ch [Department of Radiation Oncology, Geneva University Hospital, Geneva (Switzerland); Zilli, Thomas [Department of Radiation Oncology, Geneva University Hospital, Geneva (Switzerland); Vallee, Jean Paul [Department of Diagnostic Radiology, Geneva University Hospital, Geneva (Switzerland); Rouzaud, Michel; Miralbell, Raymond [Department of Radiation Oncology, Geneva University Hospital, Geneva (Switzerland); Cozzi, Luca [Oncology Institute of Southern Switzerland, Medical Physics Unit, Bellinzona (Switzerland)

    2012-11-01

    Purpose: Rectal toxicity is a serious adverse effect in early-stage prostate cancer patients treated with curative radiation therapy (RT). Injecting a spacer between Denonvilliers' fascia increases the distance between the prostate and the anterior rectal wall and may thus decrease the rectal radiation-induced toxicity. We assessed the dosimetric impact of this spacer with advanced delivery RT techniques, including intensity modulated RT (IMRT), volumetric modulated arc therapy (VMAT), and intensity modulated proton beam RT (IMPT). Methods and Materials: Eight prostate cancer patients were simulated for RT with or without spacer. Plans were computed for IMRT, VMAT, and IMPT using the Eclipse treatment planning system using both computed tomography spacer+ and spacer- data sets. Prostate {+-} seminal vesicle planning target volume [PTV] and organs at risk (OARs) dose-volume histograms were calculated. The results were analyzed using dose and volume metrics for comparative planning. Results: Regardless of the radiation technique, spacer injection decreased significantly the rectal dose in the 60- to 70-Gy range. Mean V{sub 70Gy} and V{sub 60Gy} with IMRT, VMAT, and IMPT planning were 5.3 {+-} 3.3%/13.9 {+-} 10.0%, 3.9 {+-} 3.2%/9.7 {+-} 5.7%, and 5.0 {+-} 3.5%/9.5 {+-} 4.7% after spacer injection. Before spacer administration, the corresponding values were 9.8 {+-} 5.4% (P=.012)/24.8 {+-} 7.8% (P=.012), 10.1 {+-} 3.0% (P=.002)/17.9 {+-} 3.9% (P=.003), and 9.7 {+-} 2.6% (P=.003)/14.7% {+-} 2.7% (P=.003). Importantly, spacer injection usually improved the PTV coverage for IMRT. With this technique, mean V{sub 70.2Gy} (P=.07) and V{sub 74.1Gy} (P=0.03) were 100 {+-} 0% to 99.8 {+-} 0.2% and 99.1 {+-} 1.2% to 95.8 {+-} 4.6% with and without Spacer, respectively. As a result of spacer injection, bladder doses were usually higher but not significantly so. Only IMPT managed to decrease the rectal dose after spacer injection for all dose levels, generally with no

  1. Influence of an interpositional spacer on the behaviour of the tibiofemoral joint: a finite element study.

    Science.gov (United States)

    Checa, S; Taylor, M; New, A

    2008-10-01

    Interpositional arthroplasty is considered by many surgeons for the treatment of isolated medial compartment osteoarthritis of the knee. In this procedure, an interpositional spacer is inserted into the medial compartment of the joint with no bone resection and no mechanical fixation. Major problems such as implant dislocation, severe pain or need for revision have been reported post-operatively. In this study, the kinematics of a knee implanted with an interpositional spacer made of either polyurethane or cobalt-chrome during walking, stair ascent and squatting cycles have been predicted and compared to the normal knee using finite element analysis. In addition, articular cartilage stress histories have been examined to obtain distributions of cumulative stress, a measure of the likelihood of articular cartilage degeneration. The insertion of a polyurethane interpositional spacer in the medial side of the knee did not affect knee kinematics as compared to the normal knee, but caused an increase of articular cartilage cumulative contact stress exposures in the medial compartment of the joint. The knee implanted with the Co-Cr spacer exhibited similar trends in knee kinematics, however significantly different ranges of motion were observed during some periods of the activity cycles, specifically during the first half of the walking cycle where lower ranges of motion were predicted. In addition, higher articular cartilage cumulative contact stress exposures were observed in both compartments of the knee. In both cases, cumulative contact stress exposures of the tibial articular cartilage were more affected than those of the femoral articular cartilage. These results suggest implant material as an important parameter in the design phase of interpositional spacers.

  2. Development of a laser multi-layer cladding technology for damage mitigation of fuel spacers in Hanaro reactor

    International Nuclear Information System (INIS)

    Kim, J. S.; Lee, D. H.; Hwang, S. S.; Suh, J. H.

    2002-01-01

    A laser multi-layer cladding technology was developed to mitigate the fretting wear damages occurred at fuel spacers in Hanaro reactor. The detailed experimental results are as follows. 1) Analyses of fretting wear damages and fabrication process of fuel spacers 2) Development and analysis of spherical Al 6061 T-6 alloy powders for the laser cladding 3) Analysis of parameter effects on laser cladding process for clad bids, and optimization of laser cladding process 4) Analysis on the changes of cladding layers due to overlapping factor change 5) Microstructural observation and phase analysis 6) Characterization of materials properties (hardness and wear tests) 7) Manufacture of prototype fuel spacers 8) Development of a vision system and revision of its related softwares

  3. Procedure for vibration test of the fuel rod supported by spacer grids

    International Nuclear Information System (INIS)

    Choi, Myoung Hwan; Kang, Heung Seok; Yoon, Kyung Ho; Kim, Hyung Kyu; Song, Kee Nam

    2002-07-01

    One of the methods that are used to compare and verify the supporting performance of the spacer grids developed is the vibration characteristic test. In this report there are two aims. One is of the understand of the experimental method and procedure performing the modal testing using I-DEAS TDAS module. The other is the investigation of the vibration behaviors of a dummy fuel rod supported by 8 optimized H type spacer grids. This report describes the method and procedure of modal testing to obtain the vibration characteristics such as amplitudes, natural frequencies and mode shapes of the fuel rod using a shaker, a non-contact gap sensor and an accelerometer. This report provides a test procedure in detail so that anyone can be easily understood and use the I-DEAS TDAS program. The I-DEAS TDAS program related to the modal testing has several tasks including the Modal analysis, Signal Processing et al.. This report includes model preparation to prepare the geometrical model, Signal Processing (Sine/Standard measurement) to acquire the signal, Modal analysis to obtain the frequencies and mode shapes, Correlation to analyze the relation between the test and FE analysis and Post Processing tasks. In addition, this report contains the actual test and analysis data of a dummy fuel rod in length 3847mm supported by 8 optimized H type spacer grids

  4. Finite element analysis of the contact between fuel rod and spacer grid

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyung Kyu; Kim, Young Koon; Kang, Heung Seok; Yoon, Kyung Ho; Song, Kee Nam [Korea Atomic Energy Research Institute, Taejon (Korea)

    1999-01-01

    For the research on the fretting failure problem of nuclear fuel, the contact length and normal stress field are evaluated for the contact between fuel rod and spacer grid by using the Finite Element Method (FEM). An assumption of semi-infiniteness is necessary for applying the Contact Mechanics which is based on the classical theory of elasticity to the present problem. For the contact problem of fuel fretting, the contact mechanical solutions could be utilized well with sufficient accuracy if the contact bodies (i.e., the cladding tube and the spacer grid) can be assumed as semi-infinite bodies. To this end, the contact length evaluated by FEM is discussed together with the relevant research which concerned the effect of dimension for the validity of the assumption of semi-infiniteness. Normal stress profile on the contact is also studied through comparing the theoretical and the FE results. For the analysis of contact problem by FEM, ANSYS code (Version 5.3) is utilized and the geometry is chosen to be the Hertzian (cylinder-to-cylinder), the strip-to-cylinder and the fuel rod/spacer grid contact (strip-to-tube). Present research will be utilized for accessing the fuel fretting problem by FEM together with the theoretical (i.e., contact mechanical) analysis which has been published as KAERI/TR-1113/98. (author). 15 refs., 44 figs., 4 tabs.

  5. Heat Transfer Enhancement Studies in a Circular Tube Fitted with Right-Left Helical Inserts with Spacer

    OpenAIRE

    P. K. Nagarajan; P. Sivashanmugam

    2011-01-01

    Experimental investigation of heat transfer and friction factor characteristics of circular tube fitted with 300 right-left helical screw inserts with 100 mm spacer of different twist ratio has been presented for laminar and turbulent flow.. The experimental data obtained were compared with those obtained from plain tube published data. The heat transfer coefficient enhancement for 300 RL inserts with 100 mm spacer is quite comparable with for 300 R-L inserts. Performance evalu...

  6. Molecular Evidence for the Hybrid Origin of Ilex dabieshanensis (Aquifoliaceae.

    Directory of Open Access Journals (Sweden)

    Lin Shi

    Full Text Available Ilex, the largest genus of dioecious woody plants, is a good study system to assess the role of hybridization in speciation and evolution. Ilex dabieshanensis, a tree endemic to Dabieshan Mountains region, was initially described as a new species. Based on morphological intermediacy and sympatric distribution with its putative parental species, I. cornuta and I. latifolia, we proposed it as a natural hybrid between them. In this study, we sequenced one chloroplast intergenic spacer (trnH-psbA and two nuclear genes (gapC and nepGS in I. dabieshanensis and its putative parental species to test the hybrid origin hypothesis. Our results showed that there were one to two differentially fixed sequence differences between I. cornuta and I. latifolia at the two nuclear genes. Twelve of the 14 individuals of I. dabieshanensis exhibited additivity in chromatograms on these differentially fixed sites at both nuclear genes, and the remaining two exhibited additivity in chromatograms on the fixed site at only the nepGS gene. Except one haplotype of I. cornuta at the nepGS gene, all of the haplotypes of I. cornuta at the two nuclear genes were well separated from those of I. latifolia, and most haplotypes of I. dabieshanensis were shared with those of I. cornuta and I. latifolia. Phylogenetic analysis of these haplotypes was largely consistent with haplotype network analysis. I. cornuta and I. latifolia differed by two nucleotide substitutions in the chloroplast intergenic spacer, and 12 individuals of I. dabieshanensis had the same sequences as I. latifolia, while the remaining two were identical with I. cornuta. The molecular data provide convincing evidence for the hybrid origin of I. dabieshanensis and asymmetrical direction of hybridization. One haplotype of I. cornuta at the nepGS gene was nested with those of I. latifolia, indicating introgression to I. cornuta.

  7. The Construction of Chimeric T-Cell Receptor with Spacer Base of Modeling Study of VHH and MUC1 Interaction

    Directory of Open Access Journals (Sweden)

    Nazanin Pirooznia

    2011-01-01

    Full Text Available Adaptive cell immunotherapy with the use of chimeric receptors leads to the best and most specific response against tumors. Chimeric receptors consist of a signaling fragment, extracellular spacer, costimulating domain, and an antibody. Antibodies cause immunogenicity; therefore, VHH is a good replacement for ScFv in chimeric receptors. Since peptide sequences have an influence on chimeric receptors, the effect of peptide domains on each other's conformation were investigated. CD3Zeta, CD28, VHH and CD8α, and FcgIIα are used as signaling moieties, costimulating domain, antibody, and spacers, respectively. To investigate the influence of the ligation of spacers on the conformational structure of VHH, models of VHH were constructed. Molecular dynamics simulation was run to study the influence of the presence of spacers on the conformational changes in the binding sites of VHH. Root mean square deviation and root mean square fluctuation of critical segments in the binding site showed no noticeable differences with those in the native VHH. Results from molecular docking revealed that the presence of spacer FcgIIα causes an increasing effect on VHH with MUC1 interaction. Each of the constructs was transformed into the Jurkat E6.1. Expression analysis and evaluation of their functions were examined. The results showed good expression and function.

  8. Nuclear reactor fuel element assembly spacer grid and method of making

    International Nuclear Information System (INIS)

    Chetter, J.

    1975-01-01

    A cellular fuel element assembly spacer grid is described which provides for resilient bracing of fuel pins in the cells of the grid by bow spring locating members projecting inside the cells of the grid to hold the fuel pins against opposed rigid stops also projecting inside the cells of the grid. The grid comprises two tiers each formed from intersecting strip members defining cells which are penetrated by the fuel pins and arranged parallel to one another but spaced apart. The bow spring locating members extend longitudinally between the two tiers and have end ferrules which are a sliding fit on locating members which extend longitudinally from the facing inner edges of the strip members forming the two tiers. The grid tiers are fabricated individually by heat bonding the intersecting strip members prior to assembling the tiers into the spacer grid. (U.S.)

  9. CRISPR Spacer Arrays for Detection of Viral Signatures from Acidic Hot Springs

    Science.gov (United States)

    Snyder, J. C.; Bateson, M. M.; Suciu, D.; Young, M. J.

    2010-04-01

    Viruses are the most abundant life-like entities on the planet Earth. Using CRISPR spacer sequences, we have developed a microarray-based approach to detecting viral signatures in the acidic hot springs of Yellowstone.

  10. Comparing Generative and Inter-generative Subjectivity in Post-Revolutionary Academic Generations in Iran

    Directory of Open Access Journals (Sweden)

    mehran Sohrabzadeh

    2010-01-01

    Full Text Available Comparative study of different post-revolutionary generation has been broadly applied by social scientists; among them some believe there is a gulf between generations, while some others endorsing some small differences among generations, emphasis that this variety is natural. Avoiding being loyal to any of these two views, the present study attempts to compare three different post-revolutionary academic generations using theory of “generative objects” which explores generations’ view about their behaviors, Beliefs, and historical monuments. Sampling was carried among 3 generations; firstly ones who were student in 60s and now are experienced faculties in the university, secondly ones who are recently employed as faculty members, and finally who are now students in universities. Results show that in all 3 generations there are essential in-generation similarities, while comparatively there are some differentiations in inter-generative analysis.

  11. Analysis of a new strain of Euphorbia mosaic virus with distinct replication specificity unveils a lineage of begomoviruses with short Rep sequences in the DNA-B intergenic region

    Directory of Open Access Journals (Sweden)

    Argüello-Astorga Gerardo R

    2010-10-01

    Full Text Available Abstract Background Euphorbia mosaic virus (EuMV is a member of the SLCV clade, a lineage of New World begomoviruses that display distinctive features in their replication-associated protein (Rep and virion-strand replication origin. The first entirely characterized EuMV isolate is native from Yucatan Peninsula, Mexico; subsequently, EuMV was detected in weeds and pepper plants from another region of Mexico, and partial DNA-A sequences revealed significant differences in their putative replication specificity determinants with respect to EuMV-YP. This study was aimed to investigate the replication compatibility between two EuMV isolates from the same country. Results A new isolate of EuMV was obtained from pepper plants collected at Jalisco, Mexico. Full-length clones of both genomic components of EuMV-Jal were biolistically inoculated into plants of three different species, which developed symptoms indistinguishable from those induced by EuMV-YP. Pseudorecombination experiments with EuMV-Jal and EuMV-YP genomic components demonstrated that these viruses do not form infectious reassortants in Nicotiana benthamiana, presumably because of Rep-iteron incompatibility. Sequence analysis of the EuMV-Jal DNA-B intergenic region (IR led to the unexpected discovery of a 35-nt-long sequence that is identical to a segment of the rep gene in the cognate viral DNA-A. Similar short rep sequences ranging from 35- to 51-nt in length were identified in all EuMV isolates and in three distinct viruses from South America related to EuMV. These short rep sequences in the DNA-B IR are positioned downstream to a ~160-nt non-coding domain highly similar to the CP promoter of begomoviruses belonging to the SLCV clade. Conclusions EuMV strains are not compatible in replication, indicating that this begomovirus species probably is not a replicating lineage in nature. The genomic analysis of EuMV-Jal led to the discovery of a subgroup of SLCV clade viruses that contain in

  12. Analysis of the first and second internal transcribed spacer sequences of the ribosomal DNA in Biomphalaria tenagophila complex (Mollusca: Planorbidae

    Directory of Open Access Journals (Sweden)

    Teofânia HDA Vidigal

    2004-03-01

    Full Text Available The first and second internal transcribed spacer regions (ITS1 and ITS2 of the ribosomal DNA of Biomphalaria tenagophila complex (B. tenagophila, B. occidentalis, and B. t. guaibensis were sequenced and compared. The alignment lengths of these regions were about 655 bp and 481 bp, respectively. Phylogenetic relationships among the Biomphalaria species were inferred by Maximum Parsimony and Neighbor-joining methods. The phylogenetic trees produced, in most of the cases, were in accordance with morphological systematics and other molecular data previously obtained by polymerase chain reaction and restriction fragment length polymorphism analysis. The present results provide support for the proposal that B. tenagophila represents a complex comprising B. tenagophila, B. occidentalis and B. t. guaibensis.

  13. The effect of spacer grid critical component on pressure drop under both single and two phase flow conditions

    International Nuclear Information System (INIS)

    Han, B.; Yang, B.W.; Zhang, H.; Mao, H.; Zha, Y.

    2016-01-01

    As pressure drop is one of the most critical thermal hydraulic parameters for spacer grids the accurate estimation of it is the key to the design and development of spacer grids. Most of the available correlations for pressure drop do not contain any real geometrical parameters that characterize the grid effect. The main functions for spacer grid are structural support and flow mixing. Once the boundary sublayer near the rod bundle is disturbed, the liquid forms swirls or flow separation that affect pressure drop. However, under two phase flow conditions, due to the existence of steam bubble, the complexity for spacer grid are multiplied and pressure drop calculation becomes much more challenging. The influence of the dimple location, distance of mixing vane to the nearest strip, and the effect of inter-subchannel mixing among neighboring subchannels on pressure drop and downstream flow fields are analyzed in this paper. Based on this study, more detailed space grid geometry parameters are recommended for adding into the correlation when predicting pressure drop.

  14. A simulation study on the variation of virtual NMR signals by winding, bobbin, spacer error of HTS magnet

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jun Seong; Lee, Woo Seung; Kim, Jin Sub; Song, Seung Hyun; Nam, Seok Ho; Jeon, Hae Ryong; Beak, Geon Woo; Ko, Tae Kuk [Yonsei University, Seoul (Korea, Republic of)

    2016-09-15

    Recently, production technique and property of the High-Temperature Superconductor (HTS) tape have been improved. Thus, the study on applying an HTS magnet to the high magnetic field application is rapidly increased. A Nuclear Magnetic Resonance (NMR) spectrometer requires high magnitude and homogeneous of central magnetic field. However, the HTS magnet has fabrication errors because shape of HTS is tape and HTS magnet is manufactured by winding HTS tape to the bobbin. The fabrication errors are winding error, bobbin diameter error, spacer thickness error and so on. The winding error occurs when HTS tape is departed from the arranged position on the bobbin. The bobbin diameter and spacer thickness error occur since the diameter of bobbin and spacer are inaccurate. These errors lead magnitude and homogeneity of central magnetic field to be different from its ideal design. The purpose of this paper is to investigate the effect of winding error, bobbin diameter error and spacer thickness error on the central field and field homogeneity of HTS magnet using the virtual NMR signals in MATLAB simulation.

  15. Annotating long intergenic non-coding RNAs under artificial selection during chicken domestication.

    Science.gov (United States)

    Wang, Yun-Mei; Xu, Hai-Bo; Wang, Ming-Shan; Otecko, Newton Otieno; Ye, Ling-Qun; Wu, Dong-Dong; Zhang, Ya-Ping

    2017-08-15

    Numerous biological functions of long intergenic non-coding RNAs (lincRNAs) have been identified. However, the contribution of lincRNAs to the domestication process has remained elusive. Following domestication from their wild ancestors, animals display substantial changes in many phenotypic traits. Therefore, it is possible that diverse molecular drivers play important roles in this process. We analyzed 821 transcriptomes in this study and annotated 4754 lincRNA genes in the chicken genome. Our population genomic analysis indicates that 419 lincRNAs potentially evolved during artificial selection related to the domestication of chicken, while a comparative transcriptomic analysis identified 68 lincRNAs that were differentially expressed under different conditions. We also found 47 lincRNAs linked to special phenotypes. Our study provides a comprehensive view of the genome-wide landscape of lincRNAs in chicken. This will promote a better understanding of the roles of lincRNAs in domestication, and the genetic mechanisms associated with the artificial selection of domestic animals.

  16. Efficient thermal diode with ballistic spacer

    Science.gov (United States)

    Chen, Shunda; Donadio, Davide; Benenti, Giuliano; Casati, Giulio

    2018-03-01

    Thermal rectification is of importance not only for fundamental physics, but also for potential applications in thermal manipulations and thermal management. However, thermal rectification effect usually decays rapidly with system size. Here, we show that a mass-graded system, with two diffusive leads separated by a ballistic spacer, can exhibit large thermal rectification effect, with the rectification factor independent of system size. The underlying mechanism is explained in terms of the effective size-independent thermal gradient and the match or mismatch of the phonon bands. We also show the robustness of the thermal diode upon variation of the model's parameters. Our finding suggests a promising way for designing realistic efficient thermal diodes.

  17. Dependency of Tunneling-Magnetoresistance Ratio on Nanoscale Spacer Thickness and Material for Double MgO Based Perpendicular-Magnetic-Tunneling-Junction

    Science.gov (United States)

    Lee, Du-Yeong; Hong, Song-Hwa; Lee, Seung-Eun; Park, Jea-Gun

    2016-12-01

    It was found that in double MgO based perpendicular magnetic tunneling junction spin-valves ex-situ annealed at 400 °C, the tunneling magnetoresistance ratio was extremely sensitive to the material and thickness of the nanoscale spacer: it peaked at a specific thickness (0.40~0.53 nm), and the TMR ratio for W spacers (~134%) was higher than that for Ta spacers (~98%). This dependency on the spacer material and thickness was associated with the (100) body-centered-cubic crystallinity of the MgO layers: the strain enhanced diffusion length in the MgO layers of W atoms (~1.40 nm) was much shorter than that of Ta atoms (~2.85 nm) and the shorter diffusion length led to the MgO layers having better (100) body-centered-cubic crystallinity.

  18. Response of an annular electrostatic probe for a right cylindrical spacer

    DEFF Research Database (Denmark)

    Johansson, Torben; MacAllister, I. W.

    2002-01-01

    The response of an annular electrostatic probe mounted in an electrode is examined with reference to a right cylindrical spacer. The study involves using the probe λ function to derive characteristic parameters. These parameters enable the response of the probe to different charge distributions...

  19. Influence of the spacer dielectric processes on PMOS junction properties

    International Nuclear Information System (INIS)

    Morin, Pierre; Wacquant, Francois; Juhel, Marc; Laviron, Cyrille; Lenoble, D.

    2005-01-01

    In this paper, the interaction observed in PMOS transistor between the boron lightly doped drain (LDD) extensions and the spacer oxide and nitride dielectrics have been studied, with a simple experimental methodology. Low thermal budget oxide obtained by sub-atmospheric chemical vapor deposition (SACVD) and nitride deposited by plasma process have been evaluated as spacer layers. The influence of the oxide liner hydrogen content is shown to be critical for the p type shallow junction. Indeed, during the activation anneal, hydrogen content increases the boron out diffusion from the extension into the oxide liner and yield to a significant dose loss in this area. Nitride porosity has also been studied. A lower boron dose loss is observed with a porous layer because hydrogen can degas out significantly from the oxide, during anneal, through the porous nitride film. These results confirm the model of boron out diffusion based on oxide hydrogen content proposed by Kohli. Finally, a boron diffusion mechanism driven by chemistry and enhanced by hydrogen defects is proposed

  20. Feasibility Study of Interactive Game Technologies to Improve Experience with Inhaler Spacer Devices in Young Children

    OpenAIRE

    Aslam, Tariq; Shakir, Savana; Murray, Clare

    2016-01-01

    IntroductionThe correct use of inhaler devices with facemasks and spacers in young children can be difficult for both children and parents, resulting in distress for both, poor adherence and ineffective drug delivery. The aim of this study was to develop and assess the utility and impact of an interactive electronic game designed to improve the experience of spacer devices in young asthmatic children.MethodsThe Respiratory Aid For Inhaler (RAFIhaler) technology consists of a smartphone mounte...

  1. Bronchodilator Effect of Tiotropium via Respimat®Administered with a Spacer in Patients with Chronic Obstructive Pulmonary Disease (COPD).

    Science.gov (United States)

    Ogasawara, Takashi; Sakata, Jun; Aoshima, Yoichiro; Tanaka, Kazuki; Yano, Toshiaki; Kasamatsu, Norio

    2017-09-15

    Objective Among elderly patients with chronic obstructive pulmonary disease (COPD), there are some patients who cannot inhale tiotropium via Respimat ® due to poor hand-lung coordination. This study aimed to examine whether or not tiotropium inhalation therapy using Respimat ® with a spacer increased the forced expiratory volume in 1 s (FEV 1 ) in patients with COPD. Methods A randomized, crossover, single-center study was conducted in 18 patients with stable COPD. Tiotropium (5 μg) via Respimat ® with or without a spacer (AeroChamber ® ) was administered for 2 weeks. Following a 2-week washout period using a transdermal tulobuterol patch (2 mg per day), participants were then crossed over to the other inhalation therapy with respect to spacer use. The trough FEV 1 was measured at every visit using a spirometer. A questionnaire regarding inhalation therapy was administered to patients at the final visit. Results The administration of tiotropium via Respimat ® both with and without a spacer significantly increased the trough FEV 1 from baseline during each treatment period, with mean differences of 115.0±169.6 mL and 92.8±128.1 mL, respectively. There was no significant difference in the change in the trough FEV 1 between the 2 procedures (p=0.66). A total of 86% of patients reported that inhalation using a spacer was not difficult, and more than half also rated both the usage and maintenance of the AeroChamber ® as easy. Conclusion Tiotropium inhalation therapy administered via Respimat ® using a spacer exerted a bronchodilatory effect similar to that observed with tiotropium Respimat ® alone.

  2. Cold-neutron tomography of annular flow and functional spacer performance in a model of a boiling water reactor fuel rod bundle

    International Nuclear Information System (INIS)

    Zboray, Robert; Kickhofel, John; Damsohn, Manuel; Prasser, Horst-Michael

    2011-01-01

    Highlights: → Annular flows w/wo functional spacers are investigated by cold neutron imaging. → Liquid film thickness distribution on fuel pins and on spacer vanes is measured. → The influence of the spacers on the liquid film distributions has been quantified. → The cross-sectional averaged liquid hold-up significantly affected by the spacers. → The sapers affect the fraction of the entrained liquid hold up in the gas core. - Abstract: Dryout of the coolant liquid film at the upper part of the fuel pins of a boiling water reactor (BWR) core constitutes the type of heat transfer crisis relevant for the conditions of high void fractions. It is both a safety concern and a limiting factor in the thermal power and thus for the economy of BWRs. We have investigated adiabatic, air-water annular flows in a scaled-up model of two neighboring subchannels as found in BWR fuel assemblies using cold-neutron tomography. The imaging of the double suchannel has been performed at the ICON beamline at the neutron spallation source SINQ at the Paul Scherrer Institute, Switzerland. Cold-neutron tomography is shown here to be an excellent tool for investigating air-water annular flows and the influence of functional spacers of different geometries on such flows. The high-resolution, high-contrast measurements provide the spatial distributions of the coolant liquid film thickness on the fuel pin surfaces as well as on the surfaces of the spacer vanes. The axial variations of the cross-section averaged liquid hold-up and its fraction in the gas core shows the effect of the spacers on the redistribution of the two phases.

  3. INTERSPINOUS SPACER IN PERSISTENT DISCOGENIC PAIN: PERCUTANEOUS APPROACH OR OPEN TECHNIQUE

    Directory of Open Access Journals (Sweden)

    José Antonio Cruz Ricardez

    Full Text Available ABSTRACT Objective: To compare the postoperative clinical course of placement of interspinous spacer with open technique (ISO with percutaneous interspinous spacer (PIS. Methods: Quasi-experimental, longitudinal study of 42 patients with discogenic pain uncontrolled with analgesics, aged 35-55 years old, 21 women, and 21 men. Clinical history, location of pain, VAS scale before and after surgery, Oswestry Disability Index and Macnab modified scale at 6 months were used. Results: When performing quantitative analysis statistical significance (p = 0.0478, 0.0466, 0.0399 was demonstrated with Student's t test between the results according to VAS scale; in the qualitative analysis with the Oswestry index and Macnab modified scale it was demonstrated the hypothesis that the results is dependent of the surgical technique. Conclusions: According to the results, we can conclude that there is a statistically significant difference depending on the surgical technique used with respect to the rate of disability and functionality in daily life as well as in the improvement of pain symptoms.

  4. The aquatic environment as a reservoir of Vibrio cholerae O1 in hydrographic basins of the state of Pernambuco, Brazil.

    Science.gov (United States)

    Mendes-Marques, Carina Lucena; Silveira Filho, Vladimir da Mota; da Costa, Ana Paula Rocha; Nunes, Mariana de Lira; da Silva Filho, Sandoval Vieira; Figueirôa, Ângela Cristina Torres de Araújo; Hofer, Ernesto; de Almeida, Alzira Maria Paiva; Leal, Nilma Cintra

    2013-01-01

    After the worldwide cholera epidemic in 1993, permanent environmental monitoring of hydrographic basins was established in Pernambuco, Brazil, where cholera is endemic. After a quiescent period, 4 rfbN (serogroup O1) positive water samples that were culture negative were detected by multiplex single-tube nested PCR (MSTNPCR); 2 of these were also ctxA (cholera toxin) positive. From May to June 2012, 30 V. cholerae O1 isolates were obtained by culturing samples. These isolates were analyzed for the presence of virulence genes by PCR, intergenic spacer region 16S-23S PCR (ISR-PCR), and pulsed field gel electrophoresis (PFGE). The isolates were positive for the rfbN gene and negative for the assessed pathogenic genes and were classified into 2 groups by ISR and the same profile by PFGE. Close genetic similarity was observed between them (2012) and environmental strains from 2004 to 2005, indicating the permanence of endemic V. cholerae O1 in the region.

  5. The Aquatic Environment as a Reservoir of Vibrio cholerae O1 in Hydrographic Basins of the State of Pernambuco, Brazil

    Directory of Open Access Journals (Sweden)

    Carina Lucena Mendes-Marques

    2013-01-01

    Full Text Available After the worldwide cholera epidemic in 1993, permanent environmental monitoring of hydrographic basins was established in Pernambuco, Brazil, where cholera is endemic. After a quiescent period, 4 rfbN (serogroup O1 positive water samples that were culture negative were detected by multiplex single-tube nested PCR (MSTNPCR; 2 of these were also ctxA (cholera toxin positive. From May to June 2012, 30 V. cholerae O1 isolates were obtained by culturing samples. These isolates were analyzed for the presence of virulence genes by PCR, intergenic spacer region 16S-23S PCR (ISR-PCR, and pulsed field gel electrophoresis (PFGE. The isolates were positive for the rfbN gene and negative for the assessed pathogenic genes and were classified into 2 groups by ISR and the same profile by PFGE. Close genetic similarity was observed between them (2012 and environmental strains from 2004 to 2005, indicating the permanence of endemic V. cholerae O1 in the region.

  6. Impact of a Protective Vest and Spacer Garment on Exercise-Heat Strain

    National Research Council Canada - National Science Library

    Cheuvront, Samuel N; Goodman, Daniel A; Kenefick, Robert W; Montain, Scott J; Sawka, Michael N

    2008-01-01

    ...). Volunteers wore the US Army battle dress uniform (trial B), B + protective vest (trial P), and B + P + spacer garment (trial S). Biophysical clothing properties were determined and found similar to many law enforcement, industry, and sports ensembles...

  7. Rehme correlation for spacer pressure drop compared to XT-ADS rod bundle simulations and water experiment

    International Nuclear Information System (INIS)

    Batta, A.; Class, A.; Litfin, K.; Wetzel, T.

    2011-01-01

    The Rehme correlation is the most common formula to estimate the pressure drop of spacers in the design phase of new bundle geometries. It is based on considerations of momentum losses and takes into account the obstruction of the flow cross section but it ignores the geometric details of the spacer design. Within the framework of accelerator driven sub-critical reactor systems (ADS), heavy-liquid-metal (HLM) cooled fuel assemblies are considered. At the KArlsruhe Liquid metal LAboratory (KALLA) of the Karlsruhe Institute of Technology a series of experiments to quantify both pressure losses and heat transfer in HLM-cooled rod bundles are performed. The present study compares simulation results obtained with the commercial CFD code Star-CCM to experiments and the Rehme correlation. It can be shown that the Rehme correlation, simulations and experiments all yield similar trends, but quantitative predictions can only be delivered by the CFD which takes into account the full geometric details of the spacer geometry. (orig.)

  8. Vibrational modes and strain in GaN/AlN quantum dot stacks: dependence on spacer thickness

    Energy Technology Data Exchange (ETDEWEB)

    Fresneda, J.; Cros, A.; Llorens, J.M.; Garcia-Cristobal, A.; Cantarero, A. [Institut de Ciencia del Materials, Universitat de Valencia, 46071 Valencia (Spain); Amstatt, B.; Bellet-Amalric, E.; Daudin, B. [CEA-CNRS Group, Nanophysique et Semiconducteurs, DRFMC/SP2M/PSC, CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble cedex 9 (France)

    2007-06-15

    We have investigated the influence of spacer thickness on the vibrational and strain characteristics of GaN/AlN quantum dot multilayers (QD). The Raman shift corresponding to the E{sub 2h} vibrational mode related to the QDs has been analyzed for AlN thicknesses ranging from 4.4 nm to 13 nm, while the amount of GaN deposited in each layer remained constant from sample to sample. It is shown that there is a rapid blue shift of the GaN vibrational mode with spacer thickness when its value is smaller than 7 nm while it remains almost constant for thicker spacers. A rapid increase of the Raman line-width in the thicker samples is also observed. The experimental behavior is discussed in comparison with the results of a theoretical model for the strain in the QDs. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. The Optimization of Spacer Engineering for Capacitor-Less DRAM Based on the Dual-Gate Tunneling Transistor

    Science.gov (United States)

    Li, Wei; Liu, Hongxia; Wang, Shulong; Chen, Shupeng; Wang, Qianqiong

    2018-03-01

    The DRAM based on the dual-gate tunneling FET (DGTFET) has the advantages of capacitor-less structure and high retention time. In this paper, the optimization of spacer engineering for DGTFET DRAM is systematically investigated by Silvaco-Atlas tool to further improve its performance, including the reduction of reading "0" current and extension of retention time. The simulation results show that spacers at the source and drain sides should apply the low-k and high-k dielectrics, respectively, which can enhance the reading "1" current and reduce reading "0" current. Applying this optimized spacer engineering, the DGTFET DRAM obtains the optimum performance-extremely low reading "0" current (10-14A/μm) and large retention time (10s), which decreases its static power consumption and dynamic refresh rate. And the low reading "0" current also enhances its current ratio (107) of reading "1" to reading "0". Furthermore, the analysis about scalability reveals its inherent shortcoming, which offers the further investigation direction for DGTFET DRAM.

  10. Effect of electrostatic charge in plastic spacers on the lung delivery of HFA-salbutamol in children

    DEFF Research Database (Denmark)

    Anhøj, J; Bisgaard, H; Lipworth, B J

    1999-01-01

    was delivered on 3 different study days from plastic spacers with mouthpiece. Pre-treatment of the spacers differed between study days: (a) Non-electrostatic 350 ml Babyhaler (coated with benzalkonium chloride) (b) New 350 ml Babyhaler (rinsed in water), and (c) New 145 ml AeroChamber (rinsed in water). Plasma......AIMS: The effect of the electrostatic charge in plastic spacers in vivo on drug delivery to the lung of hydrofluoroalkane (HFA) salbutamol spray was studied in children. METHODS: Five children, aged 7-12 years, were included in a 3-way crossover randomised single-blind trial. Salbutamol HFA spray...... salbutamol was measured before and 5, 10, 15 and 20 min after inhalation of four single puffs of 100 microg salbutamol. Cmax and Cav (5-20min) were calculated as a reflection of lung dose. RESULTS: For Cmax: (A) Non-electrostatic Babyhaler 4.3 ng ml(-1) (B) New Babyhaler 1.9 ng ml(-1) (C) New AeroChamber 1...

  11. The Optimization of Spacer Engineering for Capacitor-Less DRAM Based on the Dual-Gate Tunneling Transistor.

    Science.gov (United States)

    Li, Wei; Liu, Hongxia; Wang, Shulong; Chen, Shupeng; Wang, Qianqiong

    2018-03-05

    The DRAM based on the dual-gate tunneling FET (DGTFET) has the advantages of capacitor-less structure and high retention time. In this paper, the optimization of spacer engineering for DGTFET DRAM is systematically investigated by Silvaco-Atlas tool to further improve its performance, including the reduction of reading "0" current and extension of retention time. The simulation results show that spacers at the source and drain sides should apply the low-k and high-k dielectrics, respectively, which can enhance the reading "1" current and reduce reading "0" current. Applying this optimized spacer engineering, the DGTFET DRAM obtains the optimum performance-extremely low reading "0" current (10 -14 A/μm) and large retention time (10s), which decreases its static power consumption and dynamic refresh rate. And the low reading "0" current also enhances its current ratio (10 7 ) of reading "1" to reading "0". Furthermore, the analysis about scalability reveals its inherent shortcoming, which offers the further investigation direction for DGTFET DRAM.

  12. The architecture of the chloroplast trnH-psbA non-coding region in angiosperms

    Czech Academy of Sciences Publication Activity Database

    Štorchová, Helena; Olson, M.S.

    2007-01-01

    Roč. 268, 1-4 (2007), s. 235-256 ISSN 0378-2697 R&D Projects: GA MŠk(CZ) LC06004 Grant - others:ESPSCor Visiting Scholar Research Grant(US) NSF DEB 0317115 Institutional research plan: CEZ:AV0Z50380511 Source of funding: V - iné verejné zdroje ; V - iné verejné zdroje Keywords : Chloroplast DNA * psbA-trnH intergenic region * Silene * deletions * insertions and inversions in stem-loop region * psbA 3´untranslated region * RNA secondary structure Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.492, year: 2007

  13. Development of a new feed channel spacer for reverse osmosis elements. Phase 2 final report, October 1, 1994--December 31, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Milstead, C.E.; Riley, R.L.

    1998-02-11

    During Phase 1, computer modeling techniques were used as the prime instrument of evaluation of designs for a new feed channel spacer to replace the 30 mil thick standard mesh (Vexar) spacer currently used in ROWPU [Reverse Osmosis Water Processing Unit] spiral-wound elements. A hemispherical peg model, based on a Bed of Nails concept developed in Phase 1, was selected for prototype production of spiral-wound elements for field testing. Evaluation in the See-Thru test cell to observe pressure drops through the spacer, feed mixing patterns and ease of cleaning fouled membrane samples showed considerable benefit over Vexar. This design would be suitable for production by roll embossing (or rotary punching) methods instead of expensive injection molding techniques. A 10{1/2} inch die set was fabricated to prove this concept using a 12 ton press brake. Due to a number of factors, however, the equipment did not work as anticipated and numerous modifications are currently in progress. This work will continue at no cost to the government until completed. A seawater test system has been constructed for field testing of various commercially available feed channel spacers for comparison with the Vexar spacer.

  14. Identification of cultured isolates of clinically important yeast species using fluorescent fragment length analysis of the amplified internally transcribed rRNA spacer 2 region

    Directory of Open Access Journals (Sweden)

    Muylaert An

    2002-07-01

    Full Text Available Abstract Background The number of patients with yeast infection has increased during the last years. Also the variety of species of clinical importance has increased. Correct species identification is often important for efficient therapy, but is currently mostly based on phenotypic features and is sometimes time-consuming and depends largely on the expertise of technicians. Therefore, we evaluated the feasibility of PCR-based amplification of the internally transcribed spacer region 2 (ITS2, followed by fragment size analysis on the ABI Prism 310 for the identification of clinically important yeasts. Results A rapid DNA-extraction method, based on simple boiling-freezing was introduced. Of the 26 species tested, 22 could be identified unambiguously by scoring the length of the ITS2-region. No distinction could be made between the species Trichosporon asteroides and T. inkin or between T. mucoides and T. ovoides. The two varieties of Cryptococcus neoformans (var. neoformans and var. gattii could be differentiated from each other due to a one bp length difference of the ITS2 fragment. The three Cryptococcus laurentii isolates were split into two groups according to their ITS2-fragment lengths, in correspondence with the phylogenetic groups described previously. Since the obtained fragment lengths compare well to those described previously and could be exchanged between two laboratories, an internationally usable library of ITS2 fragment lengths can be constructed. Conclusions The existing ITS2 size based library enables identification of most of the clinically important yeast species within 6 hours starting from a single colony and can be easily updated when new species are described. Data can be exchanged between laboratories.

  15. Successful implementation of spacer treatment guideline for acute asthma

    OpenAIRE

    Powell, C; Maskell, G; Marks, M; South, M; Robertson, C; LENNEY, W.

    2001-01-01

    AIMS—To develop and implement an evidence based guideline for the treatment of acute asthma using a metered dose inhaler and spacer combination.
METHODS—Defined strategies were used for the development and implementation of a guideline, assessed by a prospective, descriptive, study using notes review, and patient, nursing, and medical staff telephone contact. The setting was a tertiary referral hospital in Victoria, Australia with 25 000 yearly admissions, and asthma acco...

  16. Comparison of velocity and temperature fields for two types of spacers in an annular channel

    Directory of Open Access Journals (Sweden)

    Lávička David

    2012-04-01

    Full Text Available The paper deals with measurement of flow field using a modern laser method (PIV in an annular channel of very small dimension - a fuel cell model. The velocity field was measured in several positions and plains around the spacer. The measurement was extended also to record temperatures by thermocouples soldered into stainless-steel tube wall. The measurement was focused on cooling process of the preheated fuel cell tube model, where the tube was very slowly flooded with water. Main result of the paper is comparison of two spacer's designs with respect to measured velocity and temperature fields.

  17. Molecular analyses of gut contents: elucidating the feeding of co-occurring salps in the Lazarev Sea from a different perspective

    OpenAIRE

    Metfies, Katja; Nicolaus, Anja; Harbou, Lena von; Bathmann, Ulrich; Peeken, Ilka

    2014-01-01

    The diet of Antarctic salps was elucidated by investigating their gut content using “Automated Ribosomal Intergenic Spacer Analysis” and 454-pyrosequencing. Salp samples were collected during the Lazarev Krill Study in the Western Weddell Sea (summer 2005/06 and 2007/08, fall 2004, and winter 2006). Two salp species, Salpa thompsoni and Ihlea racovitzai, both occur in the Southern Ocean, can overlap geographically and seasonally. Here we provide evidence that despite the non-selective feeding...

  18. Spacer layer effect and microstructure on multi-layer [NdFeB/Nb]n films

    International Nuclear Information System (INIS)

    Tsai, J.-L.; Yao, Y.-D.; Chin, T.-S.; Kronmueller, H.

    2002-01-01

    Spacer layer effect on multi-layer [NdFeB/Nb] n films has been investigated from the variation of magnetic properties and microstructure of the films. From a HRTEM cross-section view observation, the average grain size of [NdFeB/Nb] n multi-layers was controlled by both annealing temperature and thickness of NdFeB layer. Selected area diffraction pattern indicated that the structure of Nb spacer layer was amorphous. The grain size and coercivity of [NdFeB x /Nb] n films change from 50 nm and 16.7 kOe to 167 nm and 9 kOe for films with x=40 nm, n=10 and x=200 nm, n=2, respectively

  19. Hemotropic mycoplasma infection in wild black bears (Ursus thibetanus japonicus).

    Science.gov (United States)

    Iso, Takehiro; Suzuki, Jin; Sasaoka, Fumina; Sashida, Hinako; Watanabe, Yusaku; Fujihara, Masatoshi; Nagai, Kazuya; Harasawa, Ryô

    2013-04-12

    This is the first report on Mycoplasma infection in wild bears. We report a novel hemotropic Mycoplasma (also called hemoplasma) detected in a free-ranging black bear (Ursus thibetanus japonicus) in Japan. We then used real-time PCR to look for hemoplasma DNA in blood samples collected from 15 bears and found that eight (53%) were positive. Among these eight PCR samples, seven showed a melting temperature of around 85.5°C, while the remaining one showed a single peak at 82.26°C. Almost the entire region of the 16S rRNA gene as well as the 16S-23S rRNA intergenic transcribed spacer (ITS) region from the sample that showed a melting temperature of 82.26°C was successfully amplified by means of end-point PCR. The nucleotide sequences of the 16S rRNA gene and the ITS region were then determined and compared with those of authentic Mycoplasma species. Our examinations revealed the presence of a novel hemoplasma in Japanese black bears. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Factors affecting the efficiency of aerosolized salbutamol delivery via a metered dose inhaler and equine spacer device.

    Science.gov (United States)

    Pirie, R S; McGorum, B C; Owen, C; Carr, O; Oakley, H; McLachlan, G

    2017-06-01

    Despite frequent use of metered dose inhalers (MDIs) and spacers in equine practice, limited information exists on the efficiency of aerosol delivery using such devices. We determined the particle size distribution within an MDI-generated salbutamol aerosol delivered via an equine spacer using 'best practice' delivery technique and assessed the effect of variations in MDI use technique (shaking prior to each actuation, rapid repetitive actuations, and MDI angulation) on aerosol delivery efficiency. Under optimal conditions, only 53(±18) μg salbutamol per 100 μg actuation was delivered beyond the spacer. Although this aerosol had a high [89.6% (±2.4)] fine particle (aerodynamic diameter [2.52 (±0.29) μm], and particle size variability [geometric SD - 1.66 (±0.16) μm], within all particle size fractions, there was a high coefficient of variance (31-79%) of the percentage salbutamol delivered between experimental runs, thus impeding any effort to predict drug delivery to the patient during equine inhalation therapy. Despite observable trends and with the exception of minor statistically significant changes in the least abundant particle sizes, none of the deviations from a 'best practice' delivery technique significantly altered the relative salbutamol delivery beyond the spacer, a finding which has potential relevance with regard to maintaining user compliance. © 2016 John Wiley & Sons Ltd.

  1. Intergenic DNA sequences from the human X chromosome reveal high rates of global gene flow

    Directory of Open Access Journals (Sweden)

    Wall Jeffrey D

    2008-11-01

    Full Text Available Abstract Background Despite intensive efforts devoted to collecting human polymorphism data, little is known about the role of gene flow in the ancestry of human populations. This is partly because most analyses have applied one of two simple models of population structure, the island model or the splitting model, which make unrealistic biological assumptions. Results Here, we analyze 98-kb of DNA sequence from 20 independently evolving intergenic regions on the X chromosome in a sample of 90 humans from six globally diverse populations. We employ an isolation-with-migration (IM model, which assumes that populations split and subsequently exchange migrants, to independently estimate effective population sizes and migration rates. While the maximum effective size of modern humans is estimated at ~10,000, individual populations vary substantially in size, with African populations tending to be larger (2,300–9,000 than non-African populations (300–3,300. We estimate mean rates of bidirectional gene flow at 4.8 × 10-4/generation. Bidirectional migration rates are ~5-fold higher among non-African populations (1.5 × 10-3 than among African populations (2.7 × 10-4. Interestingly, because effective sizes and migration rates are inversely related in African and non-African populations, population migration rates are similar within Africa and Eurasia (e.g., global mean Nm = 2.4. Conclusion We conclude that gene flow has played an important role in structuring global human populations and that migration rates should be incorporated as critical parameters in models of human demography.

  2. An insulating grid spacer for large-area MICROMEGAS chambers

    International Nuclear Information System (INIS)

    Bernard, D.; Delagrange, H.; D'Enterria, D.G.; Guay, M.L.M. Le; Martinez, G.; Mora, M.J.; Pichot, P.; Roy, D.; Schutz, Y.; Gandi, A.; Oliveira, R. de

    2002-01-01

    We present a novel design for large-area gaseous detectors based on the MICROMEGAS technology. This technology incorporates an insulating grid, sandwiched between the micro-mesh and the anode-pad plane, which provides a uniform 200 μm amplification gap. The uniformity of the amplification gap thickness has been verified. The gain performances of the detector are presented and compared to the values obtained with detectors using cylindrical micro spacers. The new design presents several technical and financial advantages

  3. Dansyl-naphthalimide dyads as molecular probes: effect of spacer group on metal ion binding properties.

    Science.gov (United States)

    Shankar, Balaraman H; Ramaiah, Danaboyina

    2011-11-17

    Interaction of a few dansyl-naphthalimide conjugates 1a-e linked through polymethylene spacer groups with various metal ions was investigated through absorption, fluorescence, NMR, isothermal calorimetric (ITC), and laser flash photolysis techniques. The characteristic feature of these dyads is that they exhibit competing singlet-singlet energy transfer (SSET) and photoinduced electron transfer (PET) processes, both of which decrease with the increase in spacer length. Depending on the spacer group, these dyads interact selectively with divalent Cu(2+) and Zn(2+) ions, as compared to other mono- and divalent metal ions. Jobs plot analysis showed that these dyads form 2:3 complexes with Cu(2+) ions, while 1:1 complexes were observed with Zn(2+) ions. The association constants for the Zn(2+) and Cu(2+) complexes were determined and are found to be in the order 10(3)-10(5) M(-1). Irrespective of the length of the spacer group, these dyads interestingly act as fluorescence ratiometric molecular probes for Cu(2+) ions by altering the emission intensity of both dansyl and naphthalimide chromophores. In contrast, only the fluorescence intensity of the naphthalimide chromophore of the lower homologues (n = 1-3) was altered by Zn(2+) ions. (1)H NMR and ITC measurements confirmed the involvement of both sulfonamide and dimethylamine groups in the complexation with Cu(2+) ions, while only the latter group was involved with Zn(2+) ions. Laser excitation of the dyads 1a-e showed formation of a transient absorption which can be attributed to the radical cation of the naphthalimide chromophore, whereas only the triplet excited state of the dyads 1a-e was observed in the presence of Cu(2+) ions. Uniquely, the complexation of 1a-e with Cu(2+) ions affects both PET and SSET processes, while only the PET process was partially inhibited by Zn(2+) ions in the lower homologues (n = 1-3) and the higher homologues exhibited negligible changes in their emission properties. Our results

  4. Further Studies on Arcanobacterium phocisimile: a Novel Species of Genus Arcanobacterium

    Directory of Open Access Journals (Sweden)

    Osama Sammra

    2014-01-01

    Full Text Available Arcanobacterium phocisimile, a newly described species with the type strain A. phocisimile 2698T isolated from a vaginal swab of a harbour seal and four additional A. phocisimile strains also isolated from four harbour seals could reliably be identified by phenotypic properties, by matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS, and by sequencing the genomic targets 16S rDNA and 16S-23S rDNA intergenic spacer region and the genes rpoB and gap. The A. phocisimile strains investigated in the present study were isolated together with several other bacterial species indicating that the pathogenic importance of A. phocisimile remains unclear. However, the detection of peptidic spectra by MALDI-TOF MS and the presented phenotypic and genotypic approach might help to identify A. phocisimile in future.

  5. FIVPET Flow-Induced Vibration Test Report (1) - Candidate Spacer Grid Type I (Optimized H Type)

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kang Hee; Kang, Heung Seok; Yoon, Kyung Ho; Song, Kee Nam; Kim, Jae Yong

    2006-03-15

    The flow-induced vibration (FIV) test using a 5x5 partial fuel assembly was performed to evaluate mechanical/structural performance of the candidate spacer grid type I (Optimized H shape). From the measured vibration response of the test bundle and the flow parameters, design features of the spacer strap can be analyzed in the point of vibration and hydraulic aspect, and also compared with other spacer strap in simple comparative manner. Furthermore, the FIV test will contributes to understand behaviors of nuclear fuel in operating reactor. The FIV test results will be used to verify the theoretical model of fuel rod and assembly vibration. The aim of this report is to present the results of the FIV test of partial fuel assembly and to introduce the detailed test methodology and analysis procedure. In chapter 2, the overall configuration of test bundle and instrumented tube is remarked and chapter 3 will introduce the test facility (FIVPET) and test section. Chapter 4 deals with overall test condition and procedure, measurement and data acquisition devices, instrumentation equipment and calibration, and error analysis. Finally, test result of vibration and pressure fluctuation is presented and discussed in chapter 5.

  6. Nuclear reactor spring strip grid spacer

    International Nuclear Information System (INIS)

    Patterson, J.F.; Flora, B.S.

    1980-01-01

    An improved and novel grid spacer was developed for use in nuclear reactor fuel assemblies. It is comprised of a series of intersecting support strips and a peripheral support band attached to the ends of the support strips. Each of the openings into which the fuel element is inserted has a number of protruding dimples and springs extending in different directions. The dimples coact with the springs to secure the fuel rods in the openings. Compared with previous designs, this design gives more positive alignment of the support stips while allowing greater flexibility to counterbalance the effects of thermal expansion. The springs are arranged in alternating directions so that the reaction forces tend to counterbalance each other, which in turn minimizes the reaction loads on the supporting structure. (D.N.)

  7. Mating of a PROSTALAC spacer with an intramedullary nail for reconstruction of an infected interprosthetic femoral shaft fracture: a case report.

    Science.gov (United States)

    Kamath, Atul F; Austin, Daniel; Lee, Gwo-Chin

    2012-08-01

    Reconstruction for concurrent infection of an ipsilateral total hip arthroplasty (THA) and total knee arthroplasty (TKA) is a challenge. We report a 2-stage reconstruction of a THA for chronic infection of both the THA and TKA with severe femoral bone loss secondary to interprosthetic fractures. The reconstruction involved using a custom-made, temporary, antibiotic-impregnated PROSTALAC spacer mated with an intramedullary nail. The acetabulum was then exposed and the necrotic cartilage was removed and curetted. The acetabulum was reamed to accept a PROSTALAC acetabular shell. The shell was cemented into the acetabulum with antibiotic cement. The custom-made spacer was then inserted distally first into the tibia. The distal end of the intramedullary nail was interlocked with a bicortical bolt to minimise nail rotation. Antibiotic-impregnated cement was moulded around the nail and spacer. The proximal end of the spacer was then reduced into the acetabular socket, and the joint was irrigated and the wound closed. A customised abduction brace was fitted, and partial weight bearing was allowed. Sufficient leg length, soft-tissue tension, and range of hip motion were restored, and a total femur and constrained liner was re-implanted 4 months later. Mating of an intramedullary nail with a PROSTALAC spacer is a viable reconstructive option.

  8. TALEN-mediated single-base-pair editing identification of an intergenic mutation upstream of BUB1B as causative of PCS (MVA) syndrome

    Science.gov (United States)

    Ochiai, Hiroshi; Miyamoto, Tatsuo; Kanai, Akinori; Hosoba, Kosuke; Sakuma, Tetsushi; Kudo, Yoshiki; Asami, Keiko; Ogawa, Atsushi; Watanabe, Akihiro; Kajii, Tadashi; Yamamoto, Takashi; Matsuura, Shinya

    2014-01-01

    Cancer-prone syndrome of premature chromatid separation with mosaic variegated aneuploidy [PCS (MVA) syndrome] is a rare autosomal recessive disorder characterized by constitutional aneuploidy and a high risk of childhood cancer. We previously reported monoallelic mutations in the BUB1B gene (encoding BUBR1) in seven Japanese families with the syndrome. No second mutation was found in the opposite allele of any of the families studied, although a conserved BUB1B haplotype and a decreased transcript were identified. To clarify the molecular pathology of the second allele, we extended our mutational search to a candidate region surrounding BUB1B. A unique single nucleotide substitution, G > A at ss802470619, was identified in an intergenic region 44 kb upstream of a BUB1B transcription start site, which cosegregated with the disorder. To examine whether this is the causal mutation, we designed a transcription activator-like effector nuclease–mediated two-step single-base pair editing strategy and biallelically introduced this substitution into cultured human cells. The cell clones showed reduced BUB1B transcripts, increased PCS frequency, and MVA, which are the hallmarks of the syndrome. We also encountered a case of a Japanese infant with PCS (MVA) syndrome carrying a homozygous single nucleotide substitution at ss802470619. These results suggested that the nucleotide substitution identified was the causal mutation of PCS (MVA) syndrome. PMID:24344301

  9. Effect of the spacer group nature on the optical and electrical properties of confined poly( p-phenylene vinylene) derivatives

    Science.gov (United States)

    Benzarti-Ghédira, Maha; Zahou, Imen; Hrichi, Haikel; Jaballah, Nejmeddine; Ben Chaâbane, Rafik; Majdoub, Mustapha; Ben Ouada, Hafedh

    2015-09-01

    This study is an investigation about the effect of chemical modification on the morphological, optical and electrical properties of semiconducting organic thin films. Two confined poly( p-phenylene vinylene) (PPV)-type polymers containing different spacer groups were studied: P1 has an isopropylidene spacer group and P2 with hexafluoroisopropylidene spacer. The UV-Vis absorption and PL analysis showed a stronger π- π interaction in the P1 film; in P2, the π-stacking is limited by the introduction of a bulky trifluoromethyl (CF3) groups on the spacer units. The P2 exhibits a better film quality as illustrated by the atomic force microscopy. The HOMO and LUMO energy levels and electrochemical band gap of the polymers were determinate by the cyclic voltammetry. The electrical properties of ITO/PPV derivative/Al diodes were investigated by means of current-voltage and show a space-charge-limited current conduction mechanism with higher mobility in the P2 thin layer. The impedance spectra of the devices can be discussed in terms of an equivalent circuit model designed as a parallel resistance ( R p) and capacitance ( C p) network in series with a resistance.

  10. Distribution of CRISPR spacer matches in viruses and plasmids of crenarchaeal acidothermophiles and implications for their inhibitory mechanism

    DEFF Research Database (Denmark)

    Shah, Shiraz Ali; Hansen, Niels R; Garrett, Roger A

    2009-01-01

    Transcripts from spacer sequences within chromosomal repeat clusters [CRISPRs (clusters of regularly interspaced palindromic repeats)] from archaea have been implicated in inhibiting or regulating the propagation of archaeal viruses and plasmids. For the crenarchaeal thermoacidophiles, the chromo......Transcripts from spacer sequences within chromosomal repeat clusters [CRISPRs (clusters of regularly interspaced palindromic repeats)] from archaea have been implicated in inhibiting or regulating the propagation of archaeal viruses and plasmids. For the crenarchaeal thermoacidophiles...

  11. Comparison of sequencing the D2 region of the large subunit ribosomal RNA gene (MicroSEQ®) versus the internal transcribed spacer (ITS) regions using two public databases for identification of common and uncommon clinically relevant fungal species.

    Science.gov (United States)

    Arbefeville, S; Harris, A; Ferrieri, P

    2017-09-01

    Fungal infections cause considerable morbidity and mortality in immunocompromised patients. Rapid and accurate identification of fungi is essential to guide accurately targeted antifungal therapy. With the advent of molecular methods, clinical laboratories can use new technologies to supplement traditional phenotypic identification of fungi. The aims of the study were to evaluate the sole commercially available MicroSEQ® D2 LSU rDNA Fungal Identification Kit compared to the in-house developed internal transcribed spacer (ITS) regions assay in identifying moulds, using two well-known online public databases to analyze sequenced data. 85 common and uncommon clinically relevant fungi isolated from clinical specimens were sequenced for the D2 region of the large subunit (LSU) of ribosomal RNA (rRNA) gene with the MicroSEQ® Kit and the ITS regions with the in house developed assay. The generated sequenced data were analyzed with the online GenBank and MycoBank public databases. The D2 region of the LSU rRNA gene identified 89.4% or 92.9% of the 85 isolates to the genus level and the full ITS region (f-ITS) 96.5% or 100%, using GenBank or MycoBank, respectively, when compared to the consensus ID. When comparing species-level designations to the consensus ID, D2 region of the LSU rRNA gene aligned with 44.7% (38/85) or 52.9% (45/85) of these isolates in GenBank or MycoBank, respectively. By comparison, f-ITS possessed greater specificity, followed by ITS1, then ITS2 regions using GenBank or MycoBank. Using GenBank or MycoBank, D2 region of the LSU rRNA gene outperformed phenotypic based ID at the genus level. Comparing rates of ID between D2 region of the LSU rRNA gene and the ITS regions in GenBank or MycoBank at the species level against the consensus ID, f-ITS and ITS2 exceeded performance of the D2 region of the LSU rRNA gene, but ITS1 had similar performance to the D2 region of the LSU rRNA gene using MycoBank. Our results indicated that the MicroSEQ® D2 LSU r

  12. Evaluation of the Luting Cement Space for Provisional Restoration by using Various Coats of Die Spacer Materials-An Invitro Study.

    Science.gov (United States)

    Chiramana, Sandeep; Siddineni, Krishna Chaitanya; Jyothula, Ravi Rakesh Dev; Gade, Phani Krishna; Bhupathi, Deepthi; Kondaka, Sudheer; Hussain, Zakir; Paluri, Geetha Bhavani

    2014-09-01

    The present study was to evaluate the space provided for the temporary luting cement, after the application of various coats of die spacers, during the fabrication of provisional crowns and bridges. A total of 50 specimens of dental stone with provisional crowns on all these samples were prepared and were divided into five groups based on the application of various coats of different die spacers. Later these specimens were sectioned buccolingually and were observed using a stereomicroscope under 100X magnification. The images thus obtained were evaluated and noted for the amount of space between the inner surface of the provisional crown and the specimens at five different locations using Image Pro 6.0 Express software and the values were subjected to one-way ANOVA test, and unpaired t-test. There was a significant increase of luting space thickness with various die spacer applications than the specimens of control group. Specimens of double coat applications of silver and gold die spacers showed higher luting cement space than the separating media application specimens.

  13. Absence of Cospeciation between the Uncultured Frankia Microsymbionts and the Disjunct Actinorhizal Coriaria Species

    Directory of Open Access Journals (Sweden)

    Imen Nouioui

    2014-01-01

    Full Text Available Coriaria is an actinorhizal plant that forms root nodules in symbiosis with nitrogen-fixing actinobacteria of the genus Frankia. This symbiotic association has drawn interest because of the disjunct geographical distribution of Coriaria in four separate areas of the world and in the context of evolutionary relationships between host plants and their uncultured microsymbionts. The evolution of Frankia-Coriaria symbioses was examined from a phylogenetic viewpoint using multiple genetic markers in both bacteria and host-plant partners. Total DNA extracted from root nodules collected from five species: C. myrtifolia, C. arborea, C. nepalensis, C. japonica, and C. microphylla, growing in the Mediterranean area (Morocco and France, New Zealand, Pakistan, Japan, and Mexico, respectively, was used to amplify glnA gene (glutamine synthetase, dnaA gene (chromosome replication initiator, and the nif DK IGS (intergenic spacer between nifD and nifK genes in Frankia and the matK gene (chloroplast-encoded maturase K and the intergenic transcribed spacers (18S rRNA-ITS1-5.8S rRNA-ITS2-28S rRNA in Coriaria species. Phylogenetic reconstruction indicated that the radiations of Frankia strains and Coriaria species are not congruent. The lack of cospeciation between the two symbiotic partners may be explained by host shift at high taxonomic rank together with wind dispersal and/or survival in nonhost rhizosphere.

  14. The rate-size trade-off structures intraspecific variation in Daphnia ambigua life history parameters.

    Science.gov (United States)

    DeLong, John P; Hanley, Torrance C

    2013-01-01

    The identification of trade-offs is necessary for understanding the evolution and maintenance of diversity. Here we employ the supply-demand (SD) body size optimization model to predict a trade-off between asymptotic body size and growth rate. We use the SD model to quantitatively predict the slope of the relationship between asymptotic body size and growth rate under high and low food regimes and then test the predictions against observations for Daphnia ambigua. Close quantitative agreement between observed and predicted slopes at both food levels lends support to the model and confirms that a 'rate-size' trade-off structures life history variation in this population. In contrast to classic life history expectations, growth and reproduction were positively correlated after controlling for the rate-size trade-off. We included 12 Daphnia clones in our study, but clone identity explained only some of the variation in life history traits. We also tested the hypothesis that growth rate would be positively related to intergenic spacer length (i.e. the growth rate hypothesis) across clones, but we found that clones with intermediate intergenic spacer lengths had larger asymptotic sizes and slower growth rates. Our results strongly support a resource-based optimization of body size following the SD model. Furthermore, because some resource allocation decisions necessarily precede others, understanding interdependent life history traits may require a more nested approach.

  15. The rate-size trade-off structures intraspecific variation in Daphnia ambigua life history parameters.

    Directory of Open Access Journals (Sweden)

    John P DeLong

    Full Text Available The identification of trade-offs is necessary for understanding the evolution and maintenance of diversity. Here we employ the supply-demand (SD body size optimization model to predict a trade-off between asymptotic body size and growth rate. We use the SD model to quantitatively predict the slope of the relationship between asymptotic body size and growth rate under high and low food regimes and then test the predictions against observations for Daphnia ambigua. Close quantitative agreement between observed and predicted slopes at both food levels lends support to the model and confirms that a 'rate-size' trade-off structures life history variation in this population. In contrast to classic life history expectations, growth and reproduction were positively correlated after controlling for the rate-size trade-off. We included 12 Daphnia clones in our study, but clone identity explained only some of the variation in life history traits. We also tested the hypothesis that growth rate would be positively related to intergenic spacer length (i.e. the growth rate hypothesis across clones, but we found that clones with intermediate intergenic spacer lengths had larger asymptotic sizes and slower growth rates. Our results strongly support a resource-based optimization of body size following the SD model. Furthermore, because some resource allocation decisions necessarily precede others, understanding interdependent life history traits may require a more nested approach.

  16. Application of individually performed acrylic cement spacers containing 5% of antibiotic in two-stage revision of hip and knee prosthesis due to infection.

    Science.gov (United States)

    Babiak, Ireneusz

    2012-07-03

    Deep infection of a joint endoprosthesis constitutes a threat to the stability of the implant and joint function. It requires a comprehensive and interdisciplinary approach, involving the joint revision and removal of the bacterial biofilm from all tissues, the endoprosthesis must be often removed and bone stock infection treated. The paper presents the author's experience with the use of acrylic cement spacers, custom-made during the surgery and containing low dose of an antibiotic supplemented with 5% of a selected, targeted antibiotic for the infection of hip and knee endoprostheses. 33 two-stage revisions of knee and hip joints with the use of a spacer were performed. They involved 24 knee joints and 9 hip joints. The infections were mostly caused by staphylococci MRSA (18) and MSSA (8), and in some cases Enterococci (4), Salmonella (1), Pseudomonas (1) and Acinetobacter (1). The infection was successfully treated in 31 out of 33 cases (93.93%), including 8 patients with the hip infection and 23 patients with the knee infection. The endoprosthesis was reimplanted in 30 cases: for 7 hips and 23 knees, in 3 remaining cases the endoprosthesis was not reimplanted. Mechanical complications due to the spacer occurred in 4 cases: 3 dislocations and 1 fracture (hip spacer). The patients with hip spacers were ambulatory with a partial weight bearing of the operated extremity and those with knee spacers were also ambulatory with a partial weight bearing, but the extremity was initially protected by an orthosis. The spacer enables to maintain a limb function, and making it by hand allows the addition of the specific bacteria targeted antibiotic thus increasing the likelihood of the effective antibacterial treatment.

  17. CRISPR-spacer integration reporter plasmids reveal distinct genuine acquisition specificities among CRISPR-Cas I-E variants of Escherichia coli.

    Science.gov (United States)

    Díez-Villaseñor, César; Guzmán, Noemí M; Almendros, Cristóbal; García-Martínez, Jesús; Mojica, Francisco J M

    2013-05-01

    Prokaryotes immunize themselves against transmissible genetic elements by the integration (acquisition) in clustered regularly interspaced short palindromic repeats (CRISPR) loci of spacers homologous to invader nucleic acids, defined as protospacers. Following acquisition, mono-spacer CRISPR RNAs (termed crRNAs) guide CRISPR-associated (Cas) proteins to degrade (interference) protospacers flanked by an adjacent motif in extrachomosomal DNA. During acquisition, selection of spacer-precursors adjoining the protospacer motif and proper orientation of the integrated fragment with respect to the leader (sequence leading transcription of the flanking CRISPR array) grant efficient interference by at least some CRISPR-Cas systems. This adaptive stage of the CRISPR action is poorly characterized, mainly due to the lack of appropriate genetic strategies to address its study and, at least in Escherichia coli, the need of Cas overproduction for insertion detection. In this work, we describe the development and application in Escherichia coli strains of an interference-independent assay based on engineered selectable CRISPR-spacer integration reporter plasmids. By using this tool without the constraint of interference or cas overexpression, we confirmed fundamental aspects of this process such as the critical requirement of Cas1 and Cas2 and the identity of the CTT protospacer motif for the E. coli K12 system. In addition, we defined the CWT motif for a non-K12 CRISPR-Cas variant, and obtained data supporting the implication of the leader in spacer orientation, the preferred acquisition from plasmids harboring cas genes and the occurrence of a sequential cleavage at the insertion site by a ruler mechanism.

  18. CRISPR-spacer integration reporter plasmids reveal distinct genuine acquisition specificities among CRISPR-Cas I-E variants of Escherichia coli

    Science.gov (United States)

    Díez-Villaseñor, César; Guzmán, Noemí M.; Almendros, Cristóbal; García-Martínez, Jesús; Mojica, Francisco J.M.

    2013-01-01

    Prokaryotes immunize themselves against transmissible genetic elements by the integration (acquisition) in clustered regularly interspaced short palindromic repeats (CRISPR) loci of spacers homologous to invader nucleic acids, defined as protospacers. Following acquisition, mono-spacer CRISPR RNAs (termed crRNAs) guide CRISPR-associated (Cas) proteins to degrade (interference) protospacers flanked by an adjacent motif in extrachomosomal DNA. During acquisition, selection of spacer-precursors adjoining the protospacer motif and proper orientation of the integrated fragment with respect to the leader (sequence leading transcription of the flanking CRISPR array) grant efficient interference by at least some CRISPR-Cas systems. This adaptive stage of the CRISPR action is poorly characterized, mainly due to the lack of appropriate genetic strategies to address its study and, at least in Escherichia coli, the need of Cas overproduction for insertion detection. In this work, we describe the development and application in Escherichia coli strains of an interference-independent assay based on engineered selectable CRISPR-spacer integration reporter plasmids. By using this tool without the constraint of interference or cas overexpression, we confirmed fundamental aspects of this process such as the critical requirement of Cas1 and Cas2 and the identity of the CTT protospacer motif for the E. coli K12 system. In addition, we defined the CWT motif for a non-K12 CRISPR-Cas variant, and obtained data supporting the implication of the leader in spacer orientation, the preferred acquisition from plasmids harboring cas genes and the occurrence of a sequential cleavage at the insertion site by a ruler mechanism. PMID:23445770

  19. An insulating grid spacer for large-area MICROMEGAS chambers

    CERN Document Server

    Bernard, D; D'Enterria, D G; Le Guay, M; Martínez, G; Mora, M J; Pichot, P; Roy, D; Schutz, Y; Gandi, A; De Oliveira, R

    2002-01-01

    We present an original design for large area gaseous detectors based on the MICROMEGAS technology. This technology incorporates an insulating grid, sandwiched between the micro-mesh and the anode-pad plane, which provides an uniform 200 $\\mu$m amplification gap. The uniformity of the amplification gap thickness has been verified under several experimental conditions. The gain performances of the detector are presented and compared to the values obtained with detectors using cylindrical micro spacers. The new design presents several technical and financial advantages.

  20. Campylobacter jejuni acquire new host-derived CRISPR spacers when in association with bacteriophages harbouring a CRISPR-like Cas4 protein

    Directory of Open Access Journals (Sweden)

    Ian F. Connerton

    2015-01-01

    Full Text Available Campylobacter jejuni is a worldwide cause of human diarrhoeal disease. Clustered Repetitively Interspaced Palindromic Repeats (CRISPRs and associated proteins allow Bacteria and Archaea to evade bacteriophage and plasmid infection. Type II CRISPR systems are found in association with combinations of genes encoding the CRISPR-associated Cas1, Cas2, Cas4 or Csn2, and Cas9 proteins. C. jejuni possesses a minimal subtype II-C CRISPR system containing cas1, cas2, and cas9 genes whilst cas4 is notably absent. Cas4 proteins possess 5ʹ-3ʹ exonuclease activity to create recombinogenic-ends for spacer acquisition. Here we report a conserved Cas4-like protein in Campylobacter bacteriophages that creates a novel split arrangement between the bacteriophage and host that represents a new twist in the bacteriophage/host co-evolutionary arms race. The continuous association of bacteriophage and host in the carrier state life cycle of C. jejuni provided an opportunity to study spacer acquisition in this species. Remarkably all the spacer sequences observed were of host origin. We hypothesise that Campylobacter bacteriophages can use Cas4-like protein to activate spacer acquisition to use host DNA as an effective decoy to bacteriophage DNA. Bacteria that acquire self-spacers and escape phage infection must overcome CRISPR-mediated autoimmunity either by loss of the interference functions leaving them susceptible to foreign DNA incursion or tolerate changes in gene regulation.

  1. Natural hybridization and introgression between Ligularia cymbulifera and L. tongolensis (Asteraceae, Senecioneae) in four different locations.

    Science.gov (United States)

    Yu, Jiaojun; Kuroda, Chiaki; Gong, Xun

    2014-01-01

    Natural hybridization has been considered to represent an important factor influencing the high diversity of the genus Ligularia Cass. in the Hengduan Mountains, China. Natural hybridization has been confirmed to occur frequently in Ligularia. To date, however, it has been demonstrated only within a single population. In this paper, we present evidence of natural hybridization in Ligularia from four different locations. The internal transcribed spacer (ITS) region of the nuclear ribosomal DNA and three chloroplast intergenic spacers (trnK-rps16, trnL-rpl32 and trnQ-5'rps16) of 149 accessions of putative hybrids and their putative parents (L. cymbulifera and L. tongolensis) were analyzed for evidence of hybridization. The ITS data clearly distinguished two putative parental species and sympatric L. vellerea and supported the hypothesis that those morphological intermediates were products of natural hybridization between L. cymbulifera and L. tongolensis. Moreover, several identified morphological parents were actual introgressed products. Because of hybridization and introgression, chloroplast DNA sequences generated a poorly resolved network. The present results indicate that varying degrees of hybridization and introgression occur differently depending on the habitat context. We conclude that gene flow caused by natural hybridization in Ligularia indeed plays an important role in the species diversity.

  2. Multi-Scaled Modeling the Mechanical Properties of Tubular Composites Reinforced with Innovated 3D Weft Knitted Spacer Fabrics

    Science.gov (United States)

    Omrani, Elahe; Hasani, Hossein; Dibajian, Sayed Houssain

    2018-02-01

    Textile composites of 3D integrated spacer configurations have been recently focused by several researchers all over the world. In the present study, newly-designed tubular composites reinforced with 3D spacer weft knitted fabrics were considered and the effects of their structural parameters on some applicable mechanical properties were investigated. For this purpose, two different samples of 3D spacer weft knitted textile types in tubular form were produced on an electronic flat knitting machine, using glass/nylon hybrid yarns. Thermoset tubular-shaped composite parts were manufactured via vacuum infusion molding process using epoxy resin. The mechanical properties of the produced knitted composites in term of external static and internal hydrostatic pressures were evaluated. Resistance of the produced composites against the external static and internal hydrostatic pressures was numerically simulated using multi-scale modeling method. The finding revealed that there is acceptable correlation between experimental and theoretical results.

  3. Intergenic mRNA molecules resulting from trans-splicing.

    Science.gov (United States)

    Finta, Csaba; Zaphiropoulos, Peter G

    2002-02-22

    Accumulated recent evidence is indicating that alternative splicing represents a generalized process that increases the complexity of human gene expression. Here we show that mRNA production may not necessarily be limited to single genes, as human liver also has the potential to produce a variety of hybrid cytochrome P450 3A mRNA molecules. The four known cytochrome P450 3A genes in humans, CYP3A4, CYP3A5, CYP3A7, and CYP3A43, share a high degree of similarity, consist of 13 exons with conserved exon-intron boundaries, and form a cluster on chromosome 7. The chimeric CYP3A mRNA molecules described herein are characterized by CYP3A43 exon 1 joined at canonical splice sites to distinct sets of CYP3A4 or CYP3A5 exons. Because the CYP3A43 gene is in a head-to-head orientation with the CYP3A4 and CYP3A5 genes, bypassing transcriptional termination can not account for the formation of hybrid CYP3A mRNAs. Thus, the mechanism generating these molecules has to be an RNA processing event that joins exons of independent pre-mRNA molecules, i.e. trans-splicing. Using quantitative real-time polymerase chain reaction, the ratio of one CYP3A43/3A4 intergenic combination was estimated to be approximately 0.15% that of the CYP3A43 mRNAs. Moreover, trans-splicing has been found not to interfere with polyadenylation. Heterologous expression of the chimeric species composed of CYP3A43 exon 1 joined to exons 2-13 of CYP3A4 revealed catalytic activity toward testosterone.

  4. Optical absorption enhancement by inserting ZnO optical spacer in plasmonic organic solar cells

    Science.gov (United States)

    N'Konou, Kekeli; Torchio, Philippe

    2018-01-01

    Optical absorption enhancement (AE) using coupled optical spacer and plasmonic effects in standard and inverted organic solar cells (OSCs) are demonstrated using the finite-difference time-domain numerical method. The influence of an added zinc oxide (ZnO) optical spacer layer inserted below the active layer in standard architecture is first theoretically investigated while the influence of varying the ZnO cathodic buffer layer thickness in inverted design is studied on AE. Then, the embedding of a square periodic array of core-shell silver-silica nanospheres (Ag@SiO2 NSs) at different positions in standard and inverted OSCs is performed while AE and short-circuit current density (Jsc) are calculated. As a result of previous combined effects, the optimized standard plasmonic OSCs present 15% and 79.45% enhancement in J over the reference with and without ZnO optical spacer layer, respectively, and a 16% increase of AE when Ag@SiO2 NSs are placed on top of the PEDOT:PSS layer. Compared to the inverted OSC reference, the plasmonic OSCs present 26% and 27% enhancement in J and AE, respectively, when the Ag@SiO2 NSs are located on top of the ZnO layer. Furthermore, the spatial position of these NSs in such OSCs is a key parameter for increasing light absorption via enhanced electromagnetic field distribution.

  5. Investigation of the performance behavior of a forward osmosis membrane system using various feed spacer materials fabricated by 3D printing technique.

    Science.gov (United States)

    Yanar, Numan; Son, Moon; Yang, Eunmok; Kim, Yeji; Park, Hosik; Nam, Seung-Eun; Choi, Heechul

    2018-07-01

    Recently, feed spacer research for improving the performance of a membrane module has adopted three-dimensional (3D) printing technology. This study aims to improve the performance of membrane feed spacers by using various materials and incorporating 3D printing. The samples were fabricated after modeling with 3D computer-aided design (CAD) software to investigate the mechanical strength, water flux, reverse solute flux, and fouling performances. This research was performed using acrylonitrile butadiene styrene (ABS), polypropylene (PP), and natural polylactic acid (PLA) as printing material, and the spacer model was produced using a diamond-shaped feed spacer, with a commercially available product as a reference. The 3D printed samples were initially compared in terms of size and precision with the 3D CAD model, and deviations were observed between the products and the CAD model. Then, the spacers were tested in terms of mechanical strength, water flux, reverse solute flux, and fouling (alginate-based waste water was used as a model foulant). Although there was not much difference among the samples regarding the water flux, better performances than the commercial product were obtained for reverse solute flux and fouling resistance. When comparing the prominent performance of natural PLA with the commercial product, PLA was found to have approximately 10% less fouling (based on foulant volume per unit area and root mean square roughness values), although it showed similar water flux. Thus, another approach has been introduced for using bio-degradable materials for membrane spacers. Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. Packaging design criteria modified fuel spacer burial box. Revision 1

    International Nuclear Information System (INIS)

    Stevens, P.F.

    1994-01-01

    Various Hanford facilities must transfer large radioactively contaminated items to burial/storage. Presently, there are eighteen Fuel Spacer Burial Boxes (FSBBs) available on the Hanford Site for transport of such items. Previously, the FSBBS were transported from a rail car to the burial trench via a drag-off operation. To allow for the lifting of the boxes into the burial trench, it will be necessary to improve the packagings lifting attachments and provide structural reinforcement. Additional safety improvements to the packaging system will be provided by the addition of a positive closure system and package ventilation. FSBBs that are modified in such a manner are referred to as Modified Fuel Spacer Burial Boxes (MFSBs). The criteria provided by this PDC will be used to demonstrate that the transfer of the MFSB will provide an equivalent degree of safety as would be provided by a package meeting offsite transportation requirements. This fulfills the onsite transportation safety requirements implemented in WHC-CM-2-14, Hazardous Material Packaging and Shipping. A Safety Analysis Report for Packaging (SARP) will be prepared to evaluate the safety of the transfer operation. Approval of the SARP is required to authorize transfer. Criteria are also established to ensure burial requirements are met

  7. Anti-vibration method for wind-induced vibration in cable arrays of cable-stayed bridges. Part 2. Experimental study on the efficiency of spacers as vibration dampers; Shachokyo heiretsu cable no taifu seishin taisaku. 2. Shushu no jokenka ni okeru masatsugata gensui kinotsuki spacer no yukosei

    Energy Technology Data Exchange (ETDEWEB)

    Nomura, T.; Fujiwara, A.; Ito, M. [Obayashi Corp., Tokyo (Japan)

    1997-07-10

    The present study has performed a two-dimensional sprint supporting experiment on effects imposed on vibration damping efficiency of spacers by variation in cable interval, vibration frequency, weight and diameter of parallel cables used in cable-stayed bridges. The experiment indicated phenomena varying in such a way that a characteristic having an unstable limit cycle is shown at cable intervals smaller than SH = 3.05 D, while a soft type characteristic is shown at cable intervals greater than 4.0 D. The onset velocity for wake galloping (WG) to appear increases in proportion to mass and attenuation parameters. Its increasing rate agrees nearly well with the manual type gradient. The appearance of WG can be suppressed easily when the cable intervals are greater than 4 D. The lower the cable vibration frequency, the higher the damping capability can be raised by using friction force. Because the damping performance of spacers decreases relatively when cable weight increases, the suppression effect decreases contrarily to a case of using no spacers. The wind velocity for the WG to appear when spacers are used can be evaluated by using the damping gradient. 5 refs., 20 figs., 1 tab.

  8. Experimental white piedra: a robust approach to ultrastructural analysis, scanning electron microscopy and etiological discoveries.

    Science.gov (United States)

    Inácio, Cicero P; Rocha, Ana Paula S; Barbosa, Renan do N; Oliveira, Neiva T; Silva, Josineide C; de Lima-Neto, Reginaldo G; Macêdo, Danielle Patrícia C; Neves, Rejane P

    2016-01-01

    White piedra is a fungal infection characterized by nodules comprised of Trichosporon species and restricted to the extrafollicular portion of the hair shaft. The diagnosis is based on clinical and mycological characteristics, and must be confirmed with a precise identification of the etiological agent. This research aimed to develop an in vitro infection model of white piedra and analyze its morphological and ultra-structural aspects. In the process, hair infection was induced using eight isolates of the genus Trichosporon maintained in the Culture Collection Micoteca URM. The ITS and IGS1 regions were sequenced for taxonomic confirmation. Scanning Electron Microscope (SEM) was performed at the Strategic Center for Northeast Technologies (CETENE). The scanning electron microscope was equipped with an Energy Dispersion Spectrometer (EDS). The Trichosporon isolates were identified as Trichosporon asahii (6) and Trichosporon montevideense (2) by internal transcript spacer (ITS) region and intergenic spacer 1 region (IGS1) sequencing. All eight strains were used to induce the in vitro hair infection, and nodules formed after the incubation period. Temperature variations and high humidity were not observed to be related to the development of this hair disease. The main chemical constituents detected in the nodules were carbon, nitrogen and oxygen, as well as a low level of sulfur. The absence of calcium, combined with the low level of sulfur, might explain the soft nature of the white piedra nodules. This study demonstrated that several Trichosporon species may be responsible for causing white piedra. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Complete chloroplast genome sequences of Hordeum vulgare, Sorghum bicolor and Agrostis stolonifera, and comparative analyses with other grass genomes

    Science.gov (United States)

    Saski, Christopher; Lee, Seung-Bum; Fjellheim, Siri; Guda, Chittibabu; Jansen, Robert K.; Luo, Hong; Tomkins, Jeffrey; Rognli, Odd Arne; Clarke, Jihong Liu

    2009-01-01

    Comparisons of complete chloroplast genome sequences of Hordeum vulgare, Sorghum bicolor and Agrostis stolonifera to six published grass chloroplast genomes reveal that gene content and order are similar but two microstructural changes have occurred. First, the expansion of the IR at the SSC/IRa boundary that duplicates a portion of the 5′ end of ndhH is restricted to the three genera of the subfamily Pooideae (Agrostis, Hordeum and Triticum). Second, a 6 bp deletion in ndhK is shared by Agrostis, Hordeum, Oryza and Triticum, and this event supports the sister relationship between the subfamilies Erhartoideae and Pooideae. Repeat analysis identified 19–37 direct and inverted repeats 30 bp or longer with a sequence identity of at least 90%. Seventeen of the 26 shared repeats are found in all the grass chloroplast genomes examined and are located in the same genes or intergenic spacer (IGS) regions. Examination of simple sequence repeats (SSRs) identified 16–21 potential polymorphic SSRs. Five IGS regions have 100% sequence identity among Zea mays, Saccharum officinarum and Sorghum bicolor, whereas no spacer regions were identical among Oryza sativa, Triticum aestivum, H. vulgare and A. stolonifera despite their close phylogenetic relationship. Alignment of EST sequences and DNA coding sequences identified six C–U conversions in both Sorghum bicolor and H. vulgare but only one in A. stolonifera. Phylogenetic trees based on DNA sequences of 61 protein-coding genes of 38 taxa using both maximum parsimony and likelihood methods provide moderate support for a sister relationship between the subfamilies Erhartoideae and Pooideae. PMID:17534593

  10. [Late-replicating regions in salivary gland polytene chromosomes of Drosophila melanogaster].

    Science.gov (United States)

    Kolesnikov, T D; Andreenkova, N G; Beliaeva, E S; Goncharov, F P; Zykova, T Iu; Boldyreva, L V; Pokholkova, g V; Zhimulev, I F

    2013-01-01

    About 240 specific regions that are replicated at the very end of the S-phase have been identified in D. melanogaster polytene chromosomes. These regions have a repressive chromatine state, low gene density, long intergenic distances and are enriched in tissue specific genes. In polytene chromosomes, about a quarter of these regions have no enough time to complete replication. As a result, underreplication zones represented by fewer DNA copy number, appear. We studied 60 chromosome regions that demonstrated the most pronounced under-replication. By comparing the location of these regions on a molecular map with syntenic blocks found earlier for Drosophila species by von Grotthuss et al., 2010, we have shown that across the genus Drosophila, these regions tend to have conserved gene order. This forces us to assume the existence of evolutionary mechanisms aimed at maintaining the integrity of these regions.

  11. Evolutionary history of Phakopsora pachyrhizi (the Asian soybean rust in Brazil based on nucleotide sequences of the internal transcribed spacer region of the nuclear ribosomal DNA

    Directory of Open Access Journals (Sweden)

    Maíra C. M. Freire

    2008-01-01

    Full Text Available Phakopsora pachyrhizi has dispersed globally and brought severe economic losses to soybean growers. The fungus has been established in Brazil since 2002 and is found nationwide. To gather information on the temporal and spatial patterns of genetic variation in P. pachyrhizi , we sequenced the nuclear internal transcribed spacer regions (ITS1 and ITS2. Total genomic DNA was extracted using either lyophilized urediniospores or lesions removed from infected leaves sampled from 26 soybean fields in Brazil and one field in South Africa. Cloning prior to sequencing was necessary because direct sequencing of PCR amplicons gave partially unreadable electrophoretograms with peak displacements suggestive of multiple sequences with length polymorphism. Sequences were determined from four clones per field. ITS sequences from African or Asian isolates available from the GenBank were included in the analyses. Independent sequence alignments of the ITS1 and ITS2 datasets identified 27 and 19 ribotypes, respectively. Molecular phylogeographic analyses revealed that ribotypes of widespread distribution in Brazil displayed characteristics of ancestrality and were shared with Africa and Asia, while ribotypes of rare occurrence in Brazil were indigenous. The results suggest P. pachyrhizi found in Brazil as originating from multiple, independent long-distance dispersal events.

  12. Biofouling patterns in spacer filled channels: High resolution imaging for characterization of heterogeneous biofilms

    KAUST Repository

    Staal, Marc; Siddiqui, Amber; van Loosdrecht, Mark; Vrouwenvelder, Johannes S.

    2017-01-01

    reverse osmosis (RO) and nanofiltration (NF) membrane filtration systems used for desalination and wastewater reuse to produce high quality (drinking) water. These spiral wound membrane modules contain mesh-like spacer structures used to create

  13. Design, Synthesis and Hydrolytic Behavior of Mutual Prodrugs of NSAIDs with Gabapentin Using Glycol Spacers

    Directory of Open Access Journals (Sweden)

    Hiba Najeh Alsaad

    2012-10-01

    Full Text Available The free –COOH present in NSAIDs is thought to be responsible for the GI irritation associated with all traditional NSAIDs. Exploitation of mutual prodrugs is an approach wherein the NSAID is covalently bounded to a second pharmacologically active carrier/drug with the ultimate aim of reducing the gastric irritation. In this study some NSAIDs were conjugated with gabapentin via ester bonds using glycol spacers with the expectation of reducing gastric adverse effects and obtaining synergistic analgesic effects. The kinetics of ester hydrolysis were studied in two different non enzymatic buffer solutions at pH 1.2 and 7.4, as well as in 80% human plasma using HPLC with chloroform -methanol as mobile phase. Compounds 9a–c with ethylene glycol spacers showed significant stability at buffer solutions with half lives ranging from about 8–25 h, while the underwent a reasonable plasma hydrolysis (49%–88% in 2 h. Compound 9d with a propylene glycol spacer shows a higher rate of enzymatic hydrolysis than the corresponding ethylene glycol compound 9c. The result of compounds 9a-c indicate that these compounds may be stable during their passage through the GIT until reaching the blood circulation.

  14. Insufficient sensitivity of joint aspiration during the two-stage exchange of the hip with spacers.

    Science.gov (United States)

    Boelch, Sebastian Philipp; Weissenberger, Manuel; Spohn, Frederik; Rudert, Maximilian; Luedemann, Martin

    2018-01-10

    Evaluation of infection persistence during the two-stage exchange of the hip is challenging. Joint aspiration before reconstruction is supposed to rule out infection persistence. Sensitivity and specificity of synovial fluid culture and synovial leucocyte count for detecting infection persistence during the two-stage exchange of the hip were evaluated. Ninety-two aspirations before planned joint reconstruction during the two-stage exchange with spacers of the hip were retrospectively analyzed. The sensitivity and specificity of synovial fluid culture was 4.6 and 94.3%. The sensitivity and specificity of synovial leucocyte count at a cut-off value of 2000 cells/μl was 25.0 and 96.9%. C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) values were significantly higher before prosthesis removal and reconstruction or spacer exchange (p = 0.00; p = 0.013 and p = 0.039; p = 0.002) in the infection persistence group. Receiver operating characteristic area under the curve values before prosthesis removal and reconstruction or spacer exchange for ESR were lower (0.516 and 0.635) than for CRP (0.720 and 0.671). Synovial fluid culture and leucocyte count cannot rule out infection persistence during the two-stage exchange of the hip.

  15. Using cathode spacers to minimize reactor size in air cathode microbial fuel cells

    KAUST Repository

    Yang, Qiao; Feng, Yujie; Logan, Bruce E.

    2012-01-01

    generation, indicating oxygen leakage into the reactor. The S1.5 spacer slightly increased columbic efficiencies (from 20% to 24%) as a result of reduced oxygen transfer into the system. Based on operating conditions (1000ς, CE=20%), it was estimated that 0

  16. CMPO-calix[4]arenes with spacer containing intramolecular hydrogen bonding: Effect of local rigidification on solvent extraction toward f-block elements

    International Nuclear Information System (INIS)

    Chu, Hongzhu; He, Lutao; Jiang, Qian; Fang, Yuyu; Jia, Yiming; Yuan, Xiangyang; Zou, Shuliang; Li, Xianghui; Feng, Wen; Yang, Yuanyou; Liu, Ning; Luo, Shunzhong; Yang, Yanqiu; Yang, Liang; Yuan, Lihua

    2014-01-01

    Highlights: • Three CMPO-calix[4]arenes with spacer containing intramolecular hydrogen bonds were designed and synthesized. • The influence of local rigidification caused by intramolecular hydrogen bonds upon extraction of f-elements was investigated. • Selective extraction is realized via tuning local chelating surroundings by aid of intramolecular hydrogen bonds. -- Abstract: To understand intramolecular hydrogen bonding in effecting liquid–liquid extraction behavior of CMPO-calixarenes, three CMPO-modified calix[4]arenes (CMPO-CA) 5a–5c with hydrogen-bonded spacer were designed and synthesized. The impact of spacer rotation that is hindered by introduction of intramolecular hydrogen bonding upon extraction of La 3+ , Eu 3+ , Yb 3+ , Th 4+ , and UO 2 2+ has been examined. The results show that 5b and 5c containing only one hydrogen bond with a less hindered rotation spacer extract La 3+ more efficiently than 5a containing two hydrogen bonds with a more hindered rotation spacer, demonstrating the importance of local rigidification of spacer in the design of extractants in influencing the coordination environment. The large difference in extractability between La 3+ and Yb 3+ (or Eu 3+ ) by 5b (or 5c), and the small difference by 5a, suggests intramolecular hydrogen bonding do exert pronounced influence upon selective extraction of light and heavy lanthanides. Log–log plot analysis indicates a 1:1, 2:1 and 1:1 stoichiometry (ligand/metal) for the extracted complex formed between 5b and La 3+ , Th 4+ , UO 2 2+ , respectively. Additionally, their corresponding acyclic analogs 7a–7c exhibit negligible extraction toward these metal ions. These results reveal the possibility of selective extraction via tuning local chelating surroundings of CMPO-CA by aid of intramolecular hydrogen bonding

  17. The Heterogeneity of the Internal Transcribed Spacers (ITS of rDNAs in Imperata cylindrica in Taiwan

    Directory of Open Access Journals (Sweden)

    Chi-Chu Tsai

    2000-09-01

    Full Text Available Ribosomal DNA for internal transcribed spacers ITS, ITS1, 5.8S rRNA gene, ITS2 and the adjoining regions of the 17S and 25S rRNA genes were obtained from 45 individuals of Imperata cylindrica (Cogongrass in Taiwan via PCR amplification. The length of each PCR product was 692 bp, except for one sample (about 702 bp. All ITS DNA fragments were digested with EcoRV, CfoI, BanI, HaeIII, MspI, HinfI, BstOI, Sau96I, StyI and Eco109I, respectively. The ITS, including ITS1, 5.8S rRNA gene and ITS2, were very heterogeneous within an individual of Cogongrass in Taiwan. Of 45 individuals of Cogongrass in Taiwan, the ITS1 and ITS2 regions showed at least eight type variants, and 5.8S rRNA gene showed at least five type variants among Cogongrass population in Taiwan based on PCR-amplified RFLP. In conclusion, the ITS repeat sequences from Cogongrass in Taiwan was very high heterogeneous.

  18. Identification of multiple sites suitable for insertion of foreign genes in herpes simplex virus genomes.

    Science.gov (United States)

    Morimoto, Tomomi; Arii, Jun; Akashi, Hiroomi; Kawaguchi, Yasushi

    2009-03-01

    Information on sites in HSV genomes at which foreign gene(s) can be inserted without disrupting viral genes or affecting properties of the parental virus are important for basic research on HSV and development of HSV-based vectors for human therapy. The intergenic region between HSV-1 UL3 and UL4 genes has been reported to satisfy the requirements for such an insertion site. The UL3 and UL4 genes are oriented toward the intergenic region and, therefore, insertion of a foreign gene(s) into the region between the UL3 and UL4 polyadenylation signals should not disrupt any viral genes or transcriptional units. HSV-1 and HSV-2 each have more than 10 additional regions structurally similar to the intergenic region between UL3 and UL4. In the studies reported here, it has been demonstrated that insertion of a reporter gene expression cassette into several of the HSV-1 and HSV-2 intergenic regions has no effect on viral growth in cell culture or virulence in mice, suggesting that these multiple intergenic regions may be suitable HSV sites for insertion of foreign genes.

  19. Tube spacer grid for a heat-exchanger tube bundle

    International Nuclear Information System (INIS)

    Scheidl, H.

    1976-01-01

    A tube spacer grid for a heat-exchanger tube bundle is formed by an annular grid frame having a groove formed in its inner surface in which the interspaced grid bars have their ends positioned and held in interspaced relationship by short sections of tubes passed through holes axially formed in the grid frame so that the tubes are positioned between the ends of the grid bars in the grooves. The tube sections may be cut from the same tubes used to form the tube bundle. 5 claims, 3 drawing figures

  20. Higher-order organisation of extremely amplified, potentially functional and massively methylated 5S rDNA in European pikes (Esox sp.).

    Science.gov (United States)

    Symonová, Radka; Ocalewicz, Konrad; Kirtiklis, Lech; Delmastro, Giovanni Battista; Pelikánová, Šárka; Garcia, Sonia; Kovařík, Aleš

    2017-05-18

    Pikes represent an important genus (Esox) harbouring a pre-duplication karyotype (2n = 2x = 50) of economically important salmonid pseudopolyploids. Here, we have characterized the 5S ribosomal RNA genes (rDNA) in Esox lucius and its closely related E. cisalpinus using cytogenetic, molecular and genomic approaches. Intragenomic homogeneity and copy number estimation was carried out using Illumina reads. The higher-order structure of rDNA arrays was investigated by the analysis of long PacBio reads. Position of loci on chromosomes was determined by FISH. DNA methylation was analysed by methylation-sensitive restriction enzymes. The 5S rDNA loci occupy exclusively (peri)centromeric regions on 30-38 acrocentric chromosomes in both E. lucius and E. cisalpinus. The large number of loci is accompanied by extreme amplification of genes (>20,000 copies), which is to the best of our knowledge one of the highest copy number of rRNA genes in animals ever reported. Conserved secondary structures of predicted 5S rRNAs indicate that most of the amplified genes are potentially functional. Only few SNPs were found in genic regions indicating their high homogeneity while intergenic spacers were more heterogeneous and several families were identified. Analysis of 10-30 kb-long molecules sequenced by the PacBio technology (containing about 40% of total 5S rDNA) revealed that the vast majority (96%) of genes are organised in large several kilobase-long blocks. Dispersed genes or short tandems were less common (4%). The adjacent 5S blocks were directly linked, separated by intervening DNA and even inverted. The 5S units differing in the intergenic spacers formed both homogeneous and heterogeneous (mixed) blocks indicating variable degree of homogenisation between the loci. Both E. lucius and E. cisalpinus 5S rDNA was heavily methylated at CG dinucleotides. Extreme amplification of 5S rRNA genes in the Esox genome occurred in the absence of significant pseudogenisation