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Sample records for repetitive cot-1 dna

  1. Karyotyping of Brassica oleracea L.based on rDNA and Cot-1 DNA fluorescence in situ hybridization

    Institute of Scientific and Technical Information of China (English)

    WANG Taixia; WU Chunhong; HUANG Jinyong; WEI Wenhui

    2007-01-01

    To explore an effective and reliable karyotyping method in Brassica crop plants,Cot-1 DNA was isolated from Brassica oleracea genome,labeled as probe with Biotin-Nick Translation Mix kit,in situ hybridized to mitotic spreads,and where specific fluorescent bands showed on each chromosome pair.25S and 5S rDNA were labeled as probes with DIG-Nick Translation Mix kit and Biotin-Nick Translation Mix kit,respectively,in situ hybridized to mitotic preparations,where 25S rDNA could be detected on two chromosome pairs and 5S rDNA on only one.Cot-1 DNA contains rDNA and chromosome sites identity between Cot-1 DNA and 25S rDNA was determined by dual-colour fluorescence in situ hybridization.All these showed that the karyotyping technique based on a combination of rDNA and Cot-1 DNA chromosome landmarks is superior to all but one.A more exact karyotype ofB.oleracea has been analyzed based on a combination of rDNA sites,Cot-1 DNA fluorescent bands,chromosome lengths and arm ratios.

  2. 利用粳稻基因组DNA和Cot-1 DNA探针对普通野生稻和亚洲栽培稻的比较分析%Comparative Analysis of Oryza rufipogon Griff. and Oryza sativa with Nipponbare Genomic DNA and Cot-1 DNA Probes

    Institute of Scientific and Technical Information of China (English)

    覃瑞; 李智; 刘虹; 陈雁; 蔡朝晖; 李刚

    2012-01-01

    Using genomic DNA and Cot-1 DNA of Nipponbare as probes, GISH( genimic in situ hybridization) and Cot-1 DNA FISH (fluorescence in situ hybridization ) were adopted to analyse the genomes of japonica Nipponbare, indica Guangluai 4 and Oryza rufipogon Griff. karyotype. Homologous clustering and comparative study of the above 3 genomes were also made. The results indicated that the distribution and coverage of genomic DNA and Cot-1 DNA probes in 3 rice genomes were very similar. The coverage percentage of Cot-1 DNA in Nipponbare, Guangluai 4 and Oryza rufipogon Griff. were (47.13 ±0. 18)%, (45.89 ±0.22)% and (44.24 ±0.21 )% respectively, demonstrating the high homology and close relationship among them. The highly and moderately repetitive DNA sequences played an important role in the evolution of rice species and indica-japonica genetic differentiation, since their hybridization signal distribution had their own characteristics . The chromosomes which contain less highly and moderately repetitive DNA sequences( No. 2,5,8 ) are more active in rice genome' s evolution.%以粳稻日本晴基因组DNA和Cot-1 DNA为探针,分别对日本晴、籼稻广陆矮4号和普通野生稻的染色体组进行了基因组原位杂交(GISH)和Cot-1 DNA荧光原位杂交(FISH)分析,并对3种染色体组进行了同源聚类和比较研究.结果表明:粳稻基因组DNA和Cot-1 DNA探针信号在3种水稻染色体组中的分布状况和覆盖率相似,Cot-1 DNA的覆盖率分别为(47.13±0.18)%、(45.89±0.22)%、(44.24±0.21)%,3种水稻基因组同源性高,亲缘关系接近.Cot-1 DNA在3种水稻染色体上的杂交信号分布各有特点,中高度重复序列的变异在普通野生稻向栽培稻进化和亚洲栽培稻籼、粳分化过程中具有重要意义,中高度重复序列含量较低的2、5、8号染色体是水稻染色体组进化过程中相对活跃的成分.

  3. Repetitive DNA in three Gramineae species with low DNA content.

    Science.gov (United States)

    Deshpande, V G; Ranjekar, P K

    1980-08-01

    The genomes of three Gramineae species, namely finger millet (Eleusine coracana), pearl millet (Pennisetum americanum) and rice (Oryza sativa) are characterized by studying their DNA denaturation-reassociation properties. The reassociation kinetics measurement of the sonicated DNA (500--700 nucleotide pairs) indicate the presence of a heterogeneous, repetitive DNA fraction accounting for 49--54% of the total DNA in all three species. From the cot 1/2 value of the slow reassociating DNA, the genome size is estimated as 3.0 X 10(8) np in finger millet, 7.8 X 10(8) np in pearl millet and 9.0 X 10(8) np in rice. The melting patterns of the total DNAs reveal Tm value of 88.6 degrees C in the case of pearl millet and 85.0 degrees C in the case of finger millet and rice. Total repetitive and cot 1.0 DNA fractions in all the three species are isolated and their melting properties are compared with those of respective sonicated DNAs. In finger millet, the Tm values of cot 25 and cot 1 fractions are lower by 10.8 degrees C and 12.8 degrees C, respectively, than that of sonicated DNA and thus exhibit the presence of a base pair mismatch in the range of 10.8--12.8%. In rice, the Tm values of the fractions cot 50 and cot 1 are slightly lower than that of sonicated DNA and reveal a nucleotide mismatching of only 1.8--3.8%. In the case of pearl millet cot 10 DNA fraction a high-melting DNA component (Tm = 92 degrees C) representing 12% of the total cot 10 DNA and a low-melting component with a Tm of 78 degrees C are present. In cot 1 DNA fraction of pearl millet the proportion of the high-melting component is 35% and it has a Tm or 94.8 degrees C. Optical reassociation studies of cot 1.0 DNA fractions have revealed the presence of two kinetically distinct components, namely minor fast-reassociating and major slow-reassociating, having complexities in the range of 330--390 np and 1.28 X 10(5)--6.0 X 10(5) np, respectively in pearl millet and rice and only one DNA fraction with an

  4. Repetitive DNA Sequences in Wheat and Its Relatives

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xue-yong; LI Da-yong

    2001-01-01

    Repetitive DNA sequences form a large portion of eukaryote genomes. Using wheat ( Triticum )as a model, the classification, features and functions of repetitive DNA sequences in the Tritieeae grass tribe is reviewed as well as the role of these sequences in genome differentiation, control and regulation of homologous chromosome synapsis and pairing. Transposable elements, as an important portion of dispersed repetitives,may play an essential role in gene mutation of the host. Dynamic models for change of copy number and sequences of the repetitive family are also presented after the models of Charlesworth et al. Application of repetitive DNA sequences in the study of evolution, chromosome fingerprinting and marker assisted gene transfer and breeding are described by taking wheat as an example.

  5. Polymerase Chain Reaction-based Suppression of Repetitive Sequences in Whole Chromosome Painting Probes for FISH

    Energy Technology Data Exchange (ETDEWEB)

    Dugan, L C; Pattee, M; Williams, J; Eklund, M; Bedford, J S; Christian, A T

    2004-04-21

    We have developed a method to suppress the PCR amplification of repetitive sequences in whole chromosome painting probes by adding Cot-1 DNA to the amplification mixture. The repetitive sequences in the Cot-1 DNA bind to their homologous sequences in the probe library, prevent the binding of primers, and interfere with extension of the probe sequences, greatly decreasing PCR efficiency selectively across these blocked regions. A second labeling reaction is then done and this product is resuspended in FISH hybridization mixture without further addition of blocking DNA. The hybridization produces little if any non-specific binding on any other chromosomes. We have been able to successfully use this procedure with both human and rat chromosome probes. This technique should be applicable in producing probes for CGH, M-FISH and SKY, as well as reducing the presence of repetitive DNA in genomic libraries.

  6. Analysis of repetitive DNA in chromosomes by flow cytometry.

    Science.gov (United States)

    Brind'Amour, Julie; Lansdorp, Peter M

    2011-06-01

    We developed a flow cytometry method, chromosome flow fluorescence in situ hybridization (FISH), called CFF, to analyze repetitive DNA in chromosomes using FISH with directly labeled peptide nucleic acid (PNA) probes. We used CFF to measure the abundance of interstitial telomeric sequences in Chinese hamster chromosomes and major satellite sequences in mouse chromosomes. Using CFF we also identified parental homologs of human chromosome 18 with different amounts of repetitive DNA.

  7. Directed PCR-free engineering of highly repetitive DNA sequences

    Directory of Open Access Journals (Sweden)

    Preissler Steffen

    2011-09-01

    Full Text Available Abstract Background Highly repetitive nucleotide sequences are commonly found in nature e.g. in telomeres, microsatellite DNA, polyadenine (poly(A tails of eukaryotic messenger RNA as well as in several inherited human disorders linked to trinucleotide repeat expansions in the genome. Therefore, studying repetitive sequences is of biological, biotechnological and medical relevance. However, cloning of such repetitive DNA sequences is challenging because specific PCR-based amplification is hampered by the lack of unique primer binding sites resulting in unspecific products. Results For the PCR-free generation of repetitive DNA sequences we used antiparallel oligonucleotides flanked by restriction sites of Type IIS endonucleases. The arrangement of recognition sites allowed for stepwise and seamless elongation of repetitive sequences. This facilitated the assembly of repetitive DNA segments and open reading frames encoding polypeptides with periodic amino acid sequences of any desired length. By this strategy we cloned a series of polyglutamine encoding sequences as well as highly repetitive polyadenine tracts. Such repetitive sequences can be used for diverse biotechnological applications. As an example, the polyglutamine sequences were expressed as His6-SUMO fusion proteins in Escherichia coli cells to study their aggregation behavior in vitro. The His6-SUMO moiety enabled affinity purification of the polyglutamine proteins, increased their solubility, and allowed controlled induction of the aggregation process. We successfully purified the fusions proteins and provide an example for their applicability in filter retardation assays. Conclusion Our seamless cloning strategy is PCR-free and allows the directed and efficient generation of highly repetitive DNA sequences of defined lengths by simple standard cloning procedures.

  8. A New Revised DNA Cramp Tool Based Approach of Chopping DNA Repetitive and Non-Repetitive Genome Sequences

    Directory of Open Access Journals (Sweden)

    V.Hari Prasad

    2012-11-01

    Full Text Available In vogue tremendous amount of data generated day by day by the living organism of genetic sequences and its accumulation in database, their size is growing in an exponential manner. Due to excessive storage of DNA sequences in public databases like NCBI, EMBL and DDBJ archival maintenance is tedious task. Transmission of information from one place to another place in network management systems is also a critical task. So To improve the efficiency and to reduce the overhead of the database need of compression arises in database optimization. In this connection different techniques were bloomed, but achieved results are not bountiful. Many classical algorithms are fails to compress genetic sequences due to the specificity of text encoded in dna and few of the existing techniques achieved positive results. DNA is repetitive and non repetitive in nature. Our proposed technique DNACRAMP is applicable on repetitive and non repetitive sequences of dna and it yields better compression ratio in terms of bits per bases. This is compared with existing techniques and observed that our one is the optimum technique and compression results are on par with existing techniques.

  9. Code domains in tandem repetitive DNA sequence structures.

    Science.gov (United States)

    Vogt, P

    1992-10-01

    Traditionally, many people doing research in molecular biology attribute coding properties to a given DNA sequence if this sequence contains an open reading frame for translation into a sequence of amino acids. This protein coding capability of DNA was detected about 30 years ago. The underlying genetic code is highly conserved and present in every biological species studied so far. Today, it is obvious that DNA has a much larger coding potential for other important tasks. Apart from coding for specific RNA molecules such as rRNA, snRNA and tRNA molecules, specific structural and sequence patterns of the DNA chain itself express distinct codes for the regulation and expression of its genetic activity. A chromatin code has been defined for phasing of the histone-octamer protein complex in the nucleosome. A translation frame code has been shown to exist that determines correct triplet counting at the ribosome during protein synthesis. A loop code seems to organize the single stranded interaction of the nascent RNA chain with proteins during the splicing process, and a splicing code phases successive 5' and 3' splicing sites. Most of these DNA codes are not exclusively based on the primary DNA sequence itself, but also seem to include specific features of the corresponding higher order structures. Based on the view that these various DNA codes are genetically instructive for specific molecular interactions or processes, important in the nucleus during interphase and during cell division, the coding capability of tandem repetitive DNA sequences has recently been reconsidered.

  10. Phylogenetic analysis of the genus Hordeum using repetitive DNA sequences

    DEFF Research Database (Denmark)

    Svitashev, S.; Bryngelsson, T.; Vershinin, A.

    1994-01-01

    A set of six cloned barley (Hordeum vulgare) repetitive DNA sequences was used for the analysis of phylogenetic relationships among 31 species (46 taxa) of the genus Hordeum, using molecular hybridization techniques. In situ hybridization experiments showed dispersed organization of the sequences...... over all chromosomes of H. vulgare and the wild barley species H. bulbosum, H. marinum and H. murinum. Southern blot hybridization revealed different levels of polymorphism among barley species and the RFLP data were used to generate a phylogenetic tree for the genus Hordeum. Our data are in a good...

  11. Molecular characterization and physical localization of highly repetitive DNA sequences from Brazilian Alstroemeria species

    NARCIS (Netherlands)

    Kuipers, A.G.J.; Kamstra, S.A.; Jeu, de M.J.; Jacobsen, E.

    2002-01-01

    Highly repetitive DNA sequences were isolated from genomic DNA libraries of Alstroemeria psittacina and A. inodora. Among the repetitive sequences that were isolated, tandem repeats as well as dispersed repeats could be discerned. The tandem repeats belonged to a family of interlinked Sau3A subfragm

  12. One-way sequencing of multiple amplicons from tandem repetitive mitochondrial DNA control region.

    Science.gov (United States)

    Xu, Jiawu; Fonseca, Dina M

    2011-10-01

    Repetitive DNA sequences not only exist abundantly in eukaryotic nuclear genomes, but also occur as tandem repeats in many animal mitochondrial DNA (mtDNA) control regions. Due to concerted evolution, these repetitive sequences are highly similar or even identical within a genome. When long repetitive regions are the targets of amplification for the purpose of sequencing, multiple amplicons may result if one primer has to be located inside the repeats. Here, we show that, without separating these amplicons by gel purification or cloning, directly sequencing the mitochondrial repeats with the primer outside repetitive region is feasible and efficient. We exemplify it by sequencing the mtDNA control region of the mosquito Aedes albopictus, which harbors typical large tandem DNA repeats. This one-way sequencing strategy is optimal for population surveys.

  13. Tissue culture-induced DNA methylation polymorphisms in repetitive DNA of tomato calli and regenerated plants.

    Science.gov (United States)

    Smulders, M J; Rus-Kortekaas, W; Vosman, B

    1995-12-01

    The propagation of plants through tissue culture can induce a variety of genetic and epigenetic changes. Variation in DNA methylation has been proposed as a mechanism that may explain at least a part of these changes. In the present study, the methylation of tomato callus DNA was compared with that of leaf DNA, from control or regenerated plants, at MspI/HpaII sites around five middle-repetitive sequences. Although the methylation of the internal cytosine in the recognition sequence CCGG varied from zero to nearly full methylation, depending on the probe used, no differences were found between callus and leaf DNA. For the external cytosine, small differences were revealed between leaf and callus DNA with two probes, but no polymorphisms were detected among DNA samples of calli or DNA samples of leaves of regenerated plants. When callus DNA cut with HindIII was studied with one of the probes, H9D9, most of the signal was found in high-molecular-weight DNA, as opposed to control leaf DNA where almost all the signal was in a fragment of 530 bp. Also, an extra fragment of 630 bp was found in the callus DNA that was not present in control leaf DNA. Among leaves of plants regenerated from tissue culture, the 630-bp fragment was found in 10 of 68 regenerated plants. This 630-bp fragment was present among progeny of only 4 of these 10 plants after selfing, i.e. it was partly inherited. In these cases, the fragment was not found in all progeny plants, indicating heterozygosity of the regenerated plants. The data are interpreted as indicating that a HindIII site becomes methylated in callus tissue, and that some of this methylation persists in regenerated plants and is partly transmitted to their progeny.

  14. Repetitive sequences in Eurasian lynx (Lynx lynx L.) mitochondrial DNA control region.

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    Sindičić, Magda; Gomerčić, Tomislav; Galov, Ana; Polanc, Primož; Huber, Duro; Slavica, Alen

    2012-06-01

    Mitochondrial DNA (mtDNA) control region (CR) of numerous species is known to include up to five different repetitive sequences (RS1-RS5) that are found at various locations, involving motifs of different length and extensive length heteroplasmy. Two repetitive sequences (RS2 and RS3) on opposite sides of mtDNA central conserved region have been described in domestic cat (Felis catus) and some other felid species. However, the presence of repetitive sequence RS3 has not been detected in Eurasian lynx (Lynx lynx) yet. We analyzed mtDNA CR of 35 Eurasian lynx (L. lynx L.) samples to characterize repetitive sequences and to compare them with those found in other felid species. We confirmed the presence of 80 base pairs (bp) repetitive sequence (RS2) at the 5' end of the Eurasian lynx mtDNA CR L strand and for the first time we described RS3 repetitive sequence at its 3' end, consisting of an array of tandem repeats five to ten bp long. We found that felid species share similar RS3 repetitive pattern and fundamental repeat motif TACAC.

  15. Repetitive sequences in plant nuclear DNA: types, distribution, evolution and function.

    Science.gov (United States)

    Mehrotra, Shweta; Goyal, Vinod

    2014-08-01

    Repetitive DNA sequences are a major component of eukaryotic genomes and may account for up to 90% of the genome size. They can be divided into minisatellite, microsatellite and satellite sequences. Satellite DNA sequences are considered to be a fast-evolving component of eukaryotic genomes, comprising tandemly-arrayed, highly-repetitive and highly-conserved monomer sequences. The monomer unit of satellite DNA is 150-400 base pairs (bp) in length. Repetitive sequences may be species- or genus-specific, and may be centromeric or subtelomeric in nature. They exhibit cohesive and concerted evolution caused by molecular drive, leading to high sequence homogeneity. Repetitive sequences accumulate variations in sequence and copy number during evolution, hence they are important tools for taxonomic and phylogenetic studies, and are known as "tuning knobs" in the evolution. Therefore, knowledge of repetitive sequences assists our understanding of the organization, evolution and behavior of eukaryotic genomes. Repetitive sequences have cytoplasmic, cellular and developmental effects and play a role in chromosomal recombination. In the post-genomics era, with the introduction of next-generation sequencing technology, it is possible to evaluate complex genomes for analyzing repetitive sequences and deciphering the yet unknown functional potential of repetitive sequences. Copyright © 2014 The Authors. Production and hosting by Elsevier Ltd.. All rights reserved.

  16. Distribution of repetitive DNA sequences in chromosomes of five opisthorchid species (Trematoda, Opisthorchiidae).

    Science.gov (United States)

    Zadesenets, Kira S; Karamysheva, Tatyana V; Katokhin, Alexei V; Mordvinov, Viatcheslav A; Rubtsov, Nikolay B

    2012-03-01

    Genomes of opisthorchid species are characterized by small size, suggesting a reduced amount of repetitive DNA in their genomes. Distribution of repetitive DNA sequences in the chromosomes of five species of the family Opisthorchiidae (Opisthorchis felineus 2n = 14 (Rivolta, 1884), Opisthorchis viverrini 2n = 12 (Poirier, 1886), Metorchis xanthosomus 2n = 14 (Creplin, 1846), Metorchis bilis 2n = 14 (Braun, 1890), Clonorchis sinensis 2n = 14 (Cobbold, 1875)) was studied with C- and AgNOR-banding, generation of microdissected DNA probes from individual chromosomes and fluorescent in situ hybridization on mitotic and meiotic chromosomes. Small-sized C-bands were discovered in pericentric regions of chromosomes. Ag-NOR staining of opisthorchid chromosomes and FISH with ribosomal DNA probe showed that karyotypes of all studied species were characterized by the only nucleolus organizer region in one of small chromosomes. The generation of DNA probes from chromosomes 1 and 2 of O. felineus and M. xanthosomus was performed with chromosome microdissection followed by DOP-PCR. FISH of obtained microdissected DNA probes on chromosomes of these species revealed chromosome specific DNA repeats in pericentric C-bands. It was also shown that microdissected DNA probes generated from chromosomes could be used as the Whole Chromosome Painting Probes without suppression of repetitive DNA hybridization. Chromosome painting using microdissected chromosome specific DNA probes showed the overall repeat distribution in opisthorchid chromosomes.

  17. Identification of two new repetitive elements and chromosomal mapping of repetitive DNA sequences in the fish Gymnothorax unicolor (Anguilliformes: Muraenidae

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    E. Coluccia

    2011-05-01

    Full Text Available Muraenidae is a species-rich family, with relationships among genera and species and taxonomy that have not been completely clarified. Few cytogenetic studies have been conducted on this family, and all of them showed the same diploid chromosome number (2n=42 but with conspicuous karyotypic variation among species. The Mediterranean moray eel Gymnothorax unicolor was previously cytogenetically studied using classical techniques that allowed the characterization of its karyotype structure and the constitutive heterochromatin and argyrophilic nucleolar organizer regions (Ag-NORs distribution pattern. In the present study, we describe two new repetitive elements (called GuMboI and GuDdeI obtained from restricted genomic DNA of G. unicolor that were characterized by Southern blot and physically localized by in situ hybridization on metaphase chromosomes. As they are highly repetitive DNA sequences, they map in heterochromatic regions. However, while GuDdeI was localized in the centromeric regions, the GuMboI fraction was distributed on some centromeres and was co-localized with the nucleolus organizer region (NOR. Comparative analysis with other Mediterranean species such as Muraena helena pointed out that these DNA fractions are species-specific and could potentially be used for species discrimination. As a new contribution to the karyotype of this species, we found that the major ribosomal genes are localized on acrocentric chromosome 9 and that the telomeres of each chromosome are composed of a tandem repeat derived from a poly-TTAGGG DNA sequence, as it occurs in most vertebrate species. The results obtained add new information useful in comparative genomics at the chromosomal level and contribute to the cytogenetic knowledge regarding this fish family, which has not been extensively studied.

  18. Interspecific "common" repetitive DNA sequences in salamanders of the genus Plethodon.

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    Mizuno, S; Andrews, C; Macgregor, H C

    1976-10-12

    Intermediate repetitive sequences of Plethodon cinereus which comprised about 30% of the genomic DNA were isolated and iodinated with 125I. About 5% of the 125I-repetitive fraction hybridized with a large excess of DNA from P. dunni at Cot 20. About half of the 125I-DNA in the hybrids was resistant to extensive digestion with S-1 nuclease. The average molecular size of the S-1 nuclease-resistant fraction was about 100 nucleotide pairs. The melting temperature of the S-1 nuclease-resistant fraction was about 2 degrees lower than that of the corresponding fraction made with P. cinereus DNA. These results are taken to indicate the presence in the genomes of P. cinereus and P. dunni of evolutionarily stable "common" repetitive sequences. The average frequency of repetition of the common repetitive sequences is about 6,000 X in both species. The common repetitive fraction is also present in the genomes of other species of Plethodon, although the general populations of intermediate repetitive sequences are markedly different from one species to another. The cinereus--dunni common repetitive sequences could not be detected in plethodontids belonging to different tribes, nor in more distantly related amphibians. The profiles of binding of the common repetitive sequences to CsCl or CS2SO4-Ag+ density gradient fractions of P. dunni DNA suggested that these sequences consisted of heterogeneous components with respect to base compositions, and that they did not include large amounts of the genes for ribosomal RNA, 5S RNA, 4S RNA, or histone messenger RNA. In situ hybridization of the 3H-labelled intermediate repetitive sequences of P. cinereus to male meiotic chromosomes of the same species gave autoradiographs after an exposure of seven days showing all 14 chromosomes labelled. The pattern of labelling appeared not to be random, but was impossible to analyse on account of the irregular shapes and different degrees of stretching of diplotene and prometaphase chromosomes. In

  19. The Organization of Repetitive DNA in the Genomes of Amazonian Lizard Species in the Family Teiidae.

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    Carvalho, Natalia D M; Pinheiro, Vanessa S S; Carmo, Edson J; Goll, Leonardo G; Schneider, Carlos H; Gross, Maria C

    2015-01-01

    Repetitive DNA is the largest fraction of the eukaryote genome and comprises tandem and dispersed sequences. It presents variations in relation to its composition, number of copies, distribution, dynamics, and genome organization, and participates in the evolutionary diversification of different vertebrate species. Repetitive sequences are usually located in the heterochromatin of centromeric and telomeric regions of chromosomes, contributing to chromosomal structures. Therefore, the aim of this study was to physically map repetitive DNA sequences (5S rDNA, telomeric sequences, tropomyosin gene 1, and retroelements Rex1 and SINE) of mitotic chromosomes of Amazonian species of teiids (Ameiva ameiva, Cnemidophorus sp. 1, Kentropyx calcarata, Kentropyx pelviceps, and Tupinambis teguixin) to understand their genome organization and karyotype evolution. The mapping of repetitive sequences revealed a distinct pattern in Cnemidophorus sp. 1, whereas the other species showed all sequences interspersed in the heterochromatic region. Physical mapping of the tropomyosin 1 gene was performed for the first time in lizards and showed that in addition to being functional, this gene has a structural function similar to the mapped repetitive elements as it is located preferentially in centromeric regions and termini of chromosomes.

  20. A method for generating subtractive cDNA libraries retaining clones containing repetitive elements.

    OpenAIRE

    1997-01-01

    Here we describe a two-stepped photobiotin-based procedure to enrich a target (canine retinal) cDNA library for tissue specific clones without removing those containing repetitive ( SINE ) elements, despite the presence of these elements in the driver population. In a first hybridization excess SINE elements were hybridized to a driver (canine cerebellar) cDNA. In a second hybridization target cDNA was added to this reaction. The resulting cDNA library was enriched for retinal specific clones...

  1. Molecular characterization and evolution of an interspersed repetitive DNA family of oysters.

    Science.gov (United States)

    López-Flores, Inmaculada; Ruiz-Rejón, Carmelo; Cross, Ismael; Rebordinos, Laureana; Robles, Francisca; Navajas-Pérez, Rafael; de la Herrán, Roberto

    2010-12-01

    When genomic DNA from the European flat oyster Ostrea edulis L. was digested by BclI enzyme, a band of about 150 bp was observed in agarose gel. After cloning and sequencing this band and analysing their molecular characteristics and genomic organization by means of Southern blot, in situ hybridisation, and polymerase chain reaction (PCR) protocols, we concluded that this band is an interspersed highly repeated DNA element, which is related in sequence to the flanking regions of (CT)-microsatellite loci of the species O. edulis and Crassostrea gigas. Furthermore, we determined that this element forms part of a longer repetitive unit of 268 bp in length that, at least in some loci, is present in more than one copy. By Southern blot hybridisation and PCR amplifications-using primers designed for conserved regions of the 150-bp BclI clones of O. edulis-we determined that this repetitive DNA family is conserved in five other oyster species (O. stentina, C. angulata, C. gigas, C. ariakensis, and C. sikamea) while it is apparently absent in C. gasar. Finally, based on the analysis of the repetitive units in these oyster species, we discuss the slow degree of concerted evolution in this interspersed repetitive DNA family and its use for phylogenetic analysis.

  2. Radiation-induced changes in DNA methylation of repetitive elements in the mouse heart.

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    Koturbash, Igor; Miousse, Isabelle R; Sridharan, Vijayalakshmi; Nzabarushimana, Etienne; Skinner, Charles M; Melnyk, Stepan B; Pavliv, Oleksandra; Hauer-Jensen, Martin; Nelson, Gregory A; Boerma, Marjan

    2016-05-01

    DNA methylation is a key epigenetic mechanism, needed for proper control over the expression of genetic information and silencing of repetitive elements. Exposure to ionizing radiation, aside from its strong genotoxic potential, may also affect the methylation of DNA, within the repetitive elements, in particular. In this study, we exposed C57BL/6J male mice to low absorbed mean doses of two types of space radiation-proton (0.1 Gy, 150 MeV, dose rate 0.53 ± 0.08 Gy/min), and heavy iron ions ((56)Fe) (0.5 Gy, 600 MeV/n, dose rate 0.38 ± 0.06 Gy/min). Radiation-induced changes in cardiac DNA methylation associated with repetitive elements were detected. Specifically, modest hypomethylation of retrotransposon LINE-1 was observed at day 7 after irradiation with either protons or (56)Fe. This was followed by LINE-1, and other retrotransposons, ERV2 and SINE B1, as well as major satellite DNA hypermethylation at day 90 after irradiation with (56)Fe. These changes in DNA methylation were accompanied by alterations in the expression of DNA methylation machinery and affected the one-carbon metabolism pathway. Furthermore, loss of transposable elements expression was detected in the cardiac tissue at the 90-day time-point, paralleled by substantial accumulation of mRNA transcripts, associated with major satellites. Given that the one-carbon metabolism pathway can be modulated by dietary modifications, these findings suggest a potential strategy for the mitigation and, possibly, prevention of the negative effects exerted by ionizing radiation on the cardiovascular system. Additionally, we show that the methylation status and expression of repetitive elements may serve as early biomarkers of exposure to space radiation.

  3. Radiation-induced changes in DNA methylation of repetitive elements in the mouse heart

    Energy Technology Data Exchange (ETDEWEB)

    Koturbash, Igor, E-mail: ikoturbash@uams.edu [Department of Environmental and Occupational Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205 (United States); Miousse, Isabelle R. [Department of Environmental and Occupational Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205 (United States); Sridharan, Vijayalakshmi [Division of Radiation Health, Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205 (United States); Nzabarushimana, Etienne; Skinner, Charles M. [Department of Environmental and Occupational Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205 (United States); Melnyk, Stepan B.; Pavliv, Oleksandra [Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR 72205 (United States); Hauer-Jensen, Martin [Division of Radiation Health, Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205 (United States); Surgical Service, Central Arkansas Veterans Healthcare System, Little Rock, AR 72205 (United States); Nelson, Gregory A. [Departments of Basic Sciences and Radiation Medicine, Loma Linda University, Loma Linda, CA 92354 (United States); Boerma, Marjan [Division of Radiation Health, Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205 (United States)

    2016-05-15

    Highlights: • Radiation-induced dynamic changes in cardiac DNA methylation were detected. • Early LINE-1 hypomethylation was followed by hypermethylation at a later time-point. • Radiation affected one-carbon metabolism in the heart tissue. • Irradiation resulted in accumulation of satellite DNA mRNA transcripts. - Abstract: DNA methylation is a key epigenetic mechanism, needed for proper control over the expression of genetic information and silencing of repetitive elements. Exposure to ionizing radiation, aside from its strong genotoxic potential, may also affect the methylation of DNA, within the repetitive elements, in particular. In this study, we exposed C57BL/6J male mice to low absorbed mean doses of two types of space radiation—proton (0.1 Gy, 150 MeV, dose rate 0.53 ± 0.08 Gy/min), and heavy iron ions ({sup 56}Fe) (0.5 Gy, 600 MeV/n, dose rate 0.38 ± 0.06 Gy/min). Radiation-induced changes in cardiac DNA methylation associated with repetitive elements were detected. Specifically, modest hypomethylation of retrotransposon LINE-1 was observed at day 7 after irradiation with either protons or {sup 56}Fe. This was followed by LINE-1, and other retrotransposons, ERV2 and SINE B1, as well as major satellite DNA hypermethylation at day 90 after irradiation with {sup 56}Fe. These changes in DNA methylation were accompanied by alterations in the expression of DNA methylation machinery and affected the one-carbon metabolism pathway. Furthermore, loss of transposable elements expression was detected in the cardiac tissue at the 90-day time-point, paralleled by substantial accumulation of mRNA transcripts, associated with major satellites. Given that the one-carbon metabolism pathway can be modulated by dietary modifications, these findings suggest a potential strategy for the mitigation and, possibly, prevention of the negative effects exerted by ionizing radiation on the cardiovascular system. Additionally, we show that the methylation status and

  4. Repetitive sequence analysis and karyotyping reveals centromere-associated DNA sequences in radish (Raphanus sativus L.).

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    He, Qunyan; Cai, Zexi; Hu, Tianhua; Liu, Huijun; Bao, Chonglai; Mao, Weihai; Jin, Weiwei

    2015-04-18

    Radish (Raphanus sativus L., 2n = 2x = 18) is a major root vegetable crop especially in eastern Asia. Radish root contains various nutritions which play an important role in strengthening immunity. Repetitive elements are primary components of the genomic sequence and the most important factors in genome size variations in higher eukaryotes. To date, studies about repetitive elements of radish are still limited. To better understand genome structure of radish, we undertook a study to evaluate the proportion of repetitive elements and their distribution in radish. We conducted genome-wide characterization of repetitive elements in radish with low coverage genome sequencing followed by similarity-based cluster analysis. Results showed that about 31% of the genome was composed of repetitive sequences. Satellite repeats were the most dominating elements of the genome. The distribution pattern of three satellite repeat sequences (CL1, CL25, and CL43) on radish chromosomes was characterized using fluorescence in situ hybridization (FISH). CL1 was predominantly located at the centromeric region of all chromosomes, CL25 located at the subtelomeric region, and CL43 was a telomeric satellite. FISH signals of two satellite repeats, CL1 and CL25, together with 5S rDNA and 45S rDNA, provide useful cytogenetic markers to identify each individual somatic metaphase chromosome. The centromere-specific histone H3 (CENH3) has been used as a marker to identify centromere DNA sequences. One putative CENH3 (RsCENH3) was characterized and cloned from radish. Its deduced amino acid sequence shares high similarities to those of the CENH3s in Brassica species. An antibody against B. rapa CENH3, specifically stained radish centromeres. Immunostaining and chromatin immunoprecipitation (ChIP) tests with anti-BrCENH3 antibody demonstrated that both the centromere-specific retrotransposon (CR-Radish) and satellite repeat (CL1) are directly associated with RsCENH3 in radish. Proportions

  5. The genome of the stick insect Medauroidea extradentata is strongly methylated within genes and repetitive DNA.

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    Veiko Krauss

    Full Text Available BACKGROUND: Cytosine DNA methylation has been detected in many eukaryotic organisms and has been shown to play an important role in development and disease of vertebrates including humans. Molecularly, DNA methylation appears to be involved in the suppression of initiation or of elongation of transcription. Resulting organismal functions are suggested to be the regulation of gene silencing, the suppression of transposon activity and the suppression of initiation of transcription within genes. However, some data concerning the distribution of methylcytosine in insect species appear to contradict such roles. PRINCIPAL FINDINGS: By comparison of MspI and HpaII restriction patterns in genomic DNA of several insects we show that stick insects (Phasmatodea have highly methylated genomes. We isolated methylated DNA fragments from the Vietnamese Walking Stick Medauroidea extradentata (formerly known as Baculum extradentatum and demonstrated that most of the corresponding sequences are repetitive. Bisulfite sequencing of one of these fragments and of parts of conserved protein-coding genes revealed a methylcytosine content of 12.6%, mostly found at CpG, but also at CpT and CpA dinucleotides. Corresponding depletions of CpG and enrichments of TpG and CpA dinucleotides in some highly conserved protein-coding genes of Medauroidea reach a similar degree as in vertebrates and show that CpG methylation has occurred in the germline of these insects. CONCLUSIONS: Using four different methods, we demonstrate that the genome of Medauroidea extradentata is strongly methylated. Both repetitive DNA and coding genes appear to contain high levels of methylcytosines. These results argue for similar functions of DNA methylation in stick insects as those already known for vertebrates.

  6. Molecular characterization and physical localization of highly repetitive DNA sequences from Brazilian Alstroemeria species.

    Science.gov (United States)

    Kuipers, A G J; Kamstra, S A; de Jeu, M J; Visser, R G F

    2002-01-01

    Highly repetitive DNA sequences were isolated from genomic DNA libraries of Alstroemeria psittacina and A. inodora. Among the repetitive sequences that were isolated, tandem repeats as well as dispersed repeats could be discerned. The tandem repeats belonged to a family of interlinked Sau3A subfragments with sizes varying from 68-127 bp, and constituted a larger HinfI repeat of approximately 400 bp. Southern hybridization showed a similar molecular organization of the tandem repeats in each of the Brazilian Alstroemeria species tested. None of the repeats hybridized with DNA from Chilean Alstroemeria species, which indicates that they are specific for the Brazilian species. In-situ localization studies revealed the tandem repeats to be localized in clusters on the chromosomes of A. inodora and A. psittacina: distal hybridization sites were found on chromosome arms 2PS, 6PL, 7PS, 7PL and 8PL, interstitial sites on chromosome arms 2PL, 3PL, 4PL and 5PL. The applicability of the tandem repeats for cytogenetic analysis of interspecific hybrids and their role in heterochromatin organization are discussed.

  7. Nonconsensus Protein Binding to Repetitive DNA Sequence Elements Significantly Affects Eukaryotic Genomes.

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    Afek, Ariel; Cohen, Hila; Barber-Zucker, Shiran; Gordân, Raluca; Lukatsky, David B

    2015-08-01

    Recent genome-wide experiments in different eukaryotic genomes provide an unprecedented view of transcription factor (TF) binding locations and of nucleosome occupancy. These experiments revealed that a large fraction of TF binding events occur in regions where only a small number of specific TF binding sites (TFBSs) have been detected. Furthermore, in vitro protein-DNA binding measurements performed for hundreds of TFs indicate that TFs are bound with wide range of affinities to different DNA sequences that lack known consensus motifs. These observations have thus challenged the classical picture of specific protein-DNA binding and strongly suggest the existence of additional recognition mechanisms that affect protein-DNA binding preferences. We have previously demonstrated that repetitive DNA sequence elements characterized by certain symmetries statistically affect protein-DNA binding preferences. We call this binding mechanism nonconsensus protein-DNA binding in order to emphasize the point that specific consensus TFBSs do not contribute to this effect. In this paper, using the simple statistical mechanics model developed previously, we calculate the nonconsensus protein-DNA binding free energy for the entire C. elegans and D. melanogaster genomes. Using the available chromatin immunoprecipitation followed by sequencing (ChIP-seq) results on TF-DNA binding preferences for ~100 TFs, we show that DNA sequences characterized by low predicted free energy of nonconsensus binding have statistically higher experimental TF occupancy and lower nucleosome occupancy than sequences characterized by high free energy of nonconsensus binding. This is in agreement with our previous analysis performed for the yeast genome. We suggest therefore that nonconsensus protein-DNA binding assists the formation of nucleosome-free regions, as TFs outcompete nucleosomes at genomic locations with enhanced nonconsensus binding. In addition, here we perform a new, large-scale analysis using

  8. Nonconsensus Protein Binding to Repetitive DNA Sequence Elements Significantly Affects Eukaryotic Genomes.

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    Ariel Afek

    2015-08-01

    Full Text Available Recent genome-wide experiments in different eukaryotic genomes provide an unprecedented view of transcription factor (TF binding locations and of nucleosome occupancy. These experiments revealed that a large fraction of TF binding events occur in regions where only a small number of specific TF binding sites (TFBSs have been detected. Furthermore, in vitro protein-DNA binding measurements performed for hundreds of TFs indicate that TFs are bound with wide range of affinities to different DNA sequences that lack known consensus motifs. These observations have thus challenged the classical picture of specific protein-DNA binding and strongly suggest the existence of additional recognition mechanisms that affect protein-DNA binding preferences. We have previously demonstrated that repetitive DNA sequence elements characterized by certain symmetries statistically affect protein-DNA binding preferences. We call this binding mechanism nonconsensus protein-DNA binding in order to emphasize the point that specific consensus TFBSs do not contribute to this effect. In this paper, using the simple statistical mechanics model developed previously, we calculate the nonconsensus protein-DNA binding free energy for the entire C. elegans and D. melanogaster genomes. Using the available chromatin immunoprecipitation followed by sequencing (ChIP-seq results on TF-DNA binding preferences for ~100 TFs, we show that DNA sequences characterized by low predicted free energy of nonconsensus binding have statistically higher experimental TF occupancy and lower nucleosome occupancy than sequences characterized by high free energy of nonconsensus binding. This is in agreement with our previous analysis performed for the yeast genome. We suggest therefore that nonconsensus protein-DNA binding assists the formation of nucleosome-free regions, as TFs outcompete nucleosomes at genomic locations with enhanced nonconsensus binding. In addition, here we perform a new, large

  9. Unique nucleotide sequence-guided assembly of repetitive DNA parts for synthetic biology applications

    Energy Technology Data Exchange (ETDEWEB)

    Torella, JP; Lienert, F; Boehm, CR; Chen, JH; Way, JC; Silver, PA

    2014-08-07

    Recombination-based DNA construction methods, such as Gibson assembly, have made it possible to easily and simultaneously assemble multiple DNA parts, and they hold promise for the development and optimization of metabolic pathways and functional genetic circuits. Over time, however, these pathways and circuits have become more complex, and the increasing need for standardization and insulation of genetic parts has resulted in sequence redundancies-for example, repeated terminator and insulator sequences-that complicate recombination-based assembly. We and others have recently developed DNA assembly methods, which we refer to collectively as unique nucleotide sequence (UNS)-guided assembly, in which individual DNA parts are flanked with UNSs to facilitate the ordered, recombination-based assembly of repetitive sequences. Here we present a detailed protocol for UNS-guided assembly that enables researchers to convert multiple DNA parts into sequenced, correctly assembled constructs, or into high-quality combinatorial libraries in only 2-3 d. If the DNA parts must be generated from scratch, an additional 2-5 d are necessary. This protocol requires no specialized equipment and can easily be implemented by a student with experience in basic cloning techniques.

  10. Differential repetitive DNA composition in the centromeric region of chromosomes of Amazonian lizard species in the family Teiidae.

    Science.gov (United States)

    Carvalho, Natalia D M; Carmo, Edson; Neves, Rogerio O; Schneider, Carlos Henrique; Gross, Maria Claudia

    2016-01-01

    Differences in heterochromatin distribution patterns and its composition were observed in Amazonian teiid species. Studies have shown repetitive DNA harbors heterochromatic blocks which are located in centromeric and telomeric regions in Ameiva ameiva (Linnaeus, 1758), Kentropyx calcarata (Spix, 1825), Kentropyx pelviceps (Cope, 1868), and Tupinambis teguixin (Linnaeus, 1758). In Cnemidophorus sp.1, repetitive DNA has multiple signals along all chromosomes. The aim of this study was to characterize moderately and highly repetitive DNA sequences by C ot1-DNA from Ameiva ameiva and Cnemidophorus sp.1 genomes through cloning and DNA sequencing, as well as mapping them chromosomally to better understand its organization and genome dynamics. The results of sequencing of DNA libraries obtained by C ot1-DNA showed that different microsatellites, transposons, retrotransposons, and some gene families also comprise the fraction of repetitive DNA in the teiid species. FISH using C ot1-DNA probes isolated from both Ameiva ameiva and Cnemidophorus sp.1 showed these sequences mainly located in heterochromatic centromeric, and telomeric regions in Ameiva ameiva, Kentropyx calcarata, Kentropyx pelviceps, and Tupinambis teguixin chromosomes, indicating they play structural and functional roles in the genome of these species. In Cnemidophorus sp.1, C ot1-DNA probe isolated from Ameiva ameiva had multiple interstitial signals on chromosomes, whereas mapping of C ot1-DNA isolated from the Ameiva ameiva and Cnemidophorus sp.1 highlighted centromeric regions of some chromosomes. Thus, the data obtained showed that many repetitive DNA classes are part of the genome of Ameiva ameiva, Cnemidophorus sp.1, Kentroyx calcarata, Kentropyx pelviceps, and Tupinambis teguixin, and these sequences are shared among the analyzed teiid species, but they were not always allocated at the same chromosome position.

  11. B chromosome in the beetle Coprophanaeus cyanescens (Scarabaeidae: emphasis in the organization of repetitive DNA sequences

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    Gomes de Oliveira Sarah

    2012-11-01

    Full Text Available Abstract Background To contribute to the knowledge of coleopteran cytogenetics, especially with respect to the genomic content of B chromosomes, we analyzed the composition and organization of repetitive DNA sequences in the Coprophanaeus cyanescens karyotype. We used conventional staining and the application of fluorescence in situ hybridization (FISH mapping using as probes C0t-1 DNA fraction, the 18S and 5S rRNA genes, and the LOA-like non-LTR transposable element (TE. Results The conventional analysis detected 3 individuals (among 50 analyzed carrying one small metacentric and mitotically unstable B chromosome. The FISH analysis revealed a pericentromeric block of C0t-1 DNA in the B chromosome but no 18S or 5S rDNA clusters in this extra element. Using the LOA-like TE probe, the FISH analysis revealed large pericentromeric blocks in eight autosomal bivalents and in the B chromosome, and a pericentromeric block extending to the short arm in one autosomal pair. No positive hybridization signal was observed for the LOA-like element in the sex chromosomes. Conclusions The results indicate that the origin of the B chromosome is associated with the autosomal elements, as demonstrated by the hybridization with C0t-1 DNA and the LOA-like TE. The present study is the first report on the cytogenetic mapping of a TE in coleopteran chromosomes. These TEs could have been involved in the origin and evolution of the B chromosome in C. cyanescens.

  12. Tissue culture-induced DNA methylation polymorphisms in repetitive DNA of tomato calli and regenerated plants

    NARCIS (Netherlands)

    Smulders, M.J.M.; Rus-Kortekaas, W.; Vosman, B.

    1995-01-01

    The propagation of plants through tissue culture can induce a variety of genetic and epigenetic changes. Variation in DNA methylation has been proposed as a mechanism that may explain at least a part of these changes. In the present study, the methylation of tomato callus DNA was compared with that

  13. Karyotype differentiation of four Cestrum species (Solanaceae based on the physical mapping of repetitive DNA

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    Jéferson Nunes Fregonezi

    2006-01-01

    Full Text Available We studied the karyotypes of four Brazilian Cestrum species (C. amictum, C. intermedium, C. sendtnerianum and C. strigilatum using conventional Feulgen staining, C-Giemsa and C-CMA3/DAPI banding, induction of cold-sensitive regions (CSRs and fluorescent in situ hybridization (FISH with rDNA probes. We found that the karyotypes of all four species was 2n = 2x = 16, with, except for the eighth acrocentric pair, a predominance of meta- and submetacentric chromosomes and various heterochromatin classes. Heterochromatic types previously unreported in Cestrum as neutral C-CMA3(0/DAPI0 bands, CMA3+ bands not associated with NORs, and C-Giemsa/CSR/DAPI- bands were found. The heterochromatic blocks varied in size, number, position and composition. The 45S rDNA probe preferentially located in the terminal and subterminal regions of some chromosomes, while 5S rDNA appeared close to the centromere of the long arm of pair 8. These results suggest that karyotype differentiation can occur mainly due to changes in repetitive DNA, with little modification in the general composition of the conventionally stained karyotype.

  14. Cooperativity between DNA Methyltransferases in the Maintenance Methylation of Repetitive Elements

    Science.gov (United States)

    Liang, Gangning; Chan, Matilda F.; Tomigahara, Yoshitaka; Tsai, Yvonne C.; Gonzales, Felicidad A.; Li, En; Laird, Peter W.; Jones, Peter A.

    2002-01-01

    We used mouse embryonic stem (ES) cells with systematic gene knockouts for DNA methyltransferases to delineate the roles of DNA methyltransferase 1 (Dnmt1) and Dnmt3a and -3b in maintaining methylation patterns in the mouse genome. Dnmt1 alone was able to maintain methylation of most CpG-poor regions analyzed. In contrast, both Dnmt1 and Dnmt3a and/or Dnmt3b were required for methylation of a select class of sequences which included abundant murine LINE-1 promoters. We used a novel hemimethylation assay to show that even in wild-type cells these sequences contain high levels of hemimethylated DNA, suggestive of poor maintenance methylation. We showed that Dnmt3a and/or -3b could restore methylation of these sequences to pretreatment levels following transient exposure of cells to 5-aza-CdR, whereas Dnmt1 by itself could not. We conclude that ongoing de novo methylation by Dnmt3a and/or Dnmt3b compensates for inefficient maintenance methylation by Dnmt1 of these endogenous repetitive sequences. Our results reveal a previously unrecognized degree of cooperativity among mammalian DNA methyltransferases in ES cells. PMID:11756544

  15. Repetitive DNA Sequences and Evolution of ZZ/ZW Sex Chromosomes in Characidium (Teleostei: Characiformes).

    Science.gov (United States)

    Scacchetti, Priscilla Cardim; Utsunomia, Ricardo; Pansonato-Alves, José Carlos; da Costa Silva, Guilherme José; Vicari, Marcelo Ricardo; Artoni, Roberto Ferreira; Oliveira, Claudio; Foresti, Fausto

    2015-01-01

    Characidium constitutes an interesting model for cytogenetic studies, since a large degree of karyotype variation has been detected in this group, like the presence/absence of sex and supernumerary chromosomes and variable distribution of repetitive sequences in different species/populations. In this study, we performed a comparative cytogenetic analysis in 13 Characidium species collected at different South American river basins in order to investigate the karyotype diversification in this group. Chromosome analyses involved the karyotype characterization, cytogenetic mapping of repetitive DNA sequences and cross-species chromosome painting using a W-specific probe obtained in a previous study from Characidium gomesi. Our results evidenced a conserved diploid chromosome number of 2n = 50, and almost all the species exhibited homeologous ZZ/ZW sex chromosomes in different stages of differentiation, except C. cf. zebra, C. tenue, C. xavante and C. stigmosum. Notably, some ZZ/ZW sex chromosomes showed 5S and/or 18S rDNA clusters, while no U2 snDNA sites could be detected in the sex chromosomes, being restricted to a single chromosome pair in almost all the analyzed species. In addition, the species Characidium sp. aff. C. vidali showed B chromosomes with an inter-individual variation of 1 to 4 supernumerary chromosomes per cell. Notably, these B chromosomes share sequences with the W-specific probe, providing insights about their origin. Results presented here further confirm the extensive karyotype diversity within Characidium in contrast with a conserved diploid chromosome number. Such chromosome differences seem to constitute a significant reproductive barrier, since several sympatric Characidium species had been described during the last few years and no interespecific hybrids were found.

  16. Physical localisation of repetitive DNA sequences in Alstroemeria: karyotyping of two species with species-specific and ribosomal DNA.

    Science.gov (United States)

    Kamstra, S A; Kuipers, A G; De Jeu, M J; Ramanna, M S; Jacobsen, E

    1997-10-01

    Fluorescence in situ hybridization (FISH) was used to localise two species-specific repetitive DNA sequences, A001-I and D32-13, and two highly conserved 25S and 5S rDNA sequences on the metaphase chromosomes of two species of Alstroemeria. The Chilean species, Alstroemeria aurea (2n = 16), has abundant constitutive heterochromatin, whereas the Brazilian species, Alstroemeria inodora, has hardly any heterochromatin. The A. aurea specific A001-I probe hybridized specifically to the C-band regions on all chromosomes. The FISH patterns on A. inodora chromosomes using species-specific probe D32-13 resembled the C-banding pattern and the A001-I pattern on A. aurea chromosomes. There were notable differences in number and distribution of rDNA sites between the two species. The 25S rDNA probe revealed 16 sites in A. aurea that closely colocalised with A001-I sites and 12 in A. inodora that were predominantly detected in the centromeric regions. FISH karyotypes of the two Alstroemeria species were constructed accordingly, enabling full identification of all individual chromosomes. These FISH karyotypes will be useful for monitoring the chromosomes of both Alstroemeria species in hybrids and backcross derivatives.

  17. Double-strand breaks associated with repetitive DNA can reshape the genome

    Science.gov (United States)

    Argueso, Juan Lucas; Westmoreland, James; Mieczkowski, Piotr A.; Gawel, Malgorzata; Petes, Thomas D.; Resnick, Michael A.

    2008-01-01

    Ionizing radiation is an established source of chromosome aberrations (CAs). Although double-strand breaks (DSBs) are implicated in radiation-induced and other CAs, the underlying mechanisms are poorly understood. Here, we show that, although the vast majority of randomly induced DSBs in G2 diploid yeast cells are repaired efficiently through homologous recombination (HR) between sister chromatids or homologous chromosomes, ≈2% of all DSBs give rise to CAs. Complete molecular analysis of the genome revealed that nearly all of the CAs resulted from HR between nonallelic repetitive elements, primarily Ty retrotransposons. Nonhomologous end-joining (NHEJ) accounted for few, if any, of the CAs. We conclude that only those DSBs that fall at the 3–5% of the genome composed of repetitive DNA elements are efficient at generating rearrangements with dispersed small repeats across the genome, whereas DSBs in unique sequences are confined to recombinational repair between the large regions of homology contained in sister chromatids or homologous chromosomes. Because repeat-associated DSBs can efficiently lead to CAs and reshape the genome, they could be a rich source of evolutionary change. PMID:18701715

  18. Cutting edge: natural DNA repetitive extragenic sequences from gram-negative pathogens strongly stimulate TLR9.

    Science.gov (United States)

    Magnusson, Mattias; Tobes, Raquel; Sancho, Jaime; Pareja, Eduardo

    2007-07-01

    Bacterial DNA exerts immunostimulatory effects on mammalian cells via the intracellular TLR9. Although broad analysis of TLR9-mediated immunostimulatory potential of synthetic oligonucleotides has been developed, which kinds of natural bacterial DNA sequences are responsible for immunostimulation are not known. This work provides evidence that the natural DNA sequences named repetitive extragenic palindromic (REPs) sequences present in Gram-negative bacteria are able to produce innate immune system stimulation via TLR9. A strong induction of IFN-alpha production by REPs from Escherichia coli, Salmonella enterica, Pseudomonas aeruginosa, and Neisseria meningitidis was detected in splenocytes from 129 mice. In addition, the involvement of TLR9 in immune stimulation by REPs was confirmed using B6.129P2-Tlr9(tm1Aki) knockout mice. Considering the involvement of TLRs in Gram-negative septic shock, it is conceivable that REPs play a role in its pathogenesis. This study highlights REPs as a potential novel target in septic shock treatment.

  19. Cloning and characterization of dispersed repetitive DNA derived from microdissected sex chromosomes of Rumex acetosa.

    Science.gov (United States)

    Mariotti, Beatrice; Navajas-Pérez, Rafael; Lozano, Rafael; Parker, John S; de la Herrán, Roberto; Rejón, Carmelo Ruiz; Rejón, Manuel Ruiz; Garrido-Ramos, Manuel; Jamilena, Manuel

    2006-02-01

    Rumex acetosa is characterized by a multiple chromosome system (2n = 12 + XX for females, and 2n = 12 + XY1Y2 for males), in which sex is determined by the ratio between the number of X chromosomes and autosome sets. For a better understanding of the molecular structure and evolution of plant sex chromosomes, we have generated a sex chromosome specific library of R. acetosa by microdissection. The screening of this library has allowed us to identify 5 repetitive DNA families that have been characterized in detail. One of these families, DOP-20, has shown no homology with other sequences in databases. Nevertheless, the putative proteins encoded by the other 4 families, DOP-8, DOP-47, DOP-60, and DOP-61, show homology with proteins from different plant retroelements, including poly proteins from Ty3-gypsy- and Ty1-copia-like long terminal repeat (LTR) retroelements, and reverse transcriptase from non-LTR retro elements. Results indicate that sequences from these 5 families are dispersed throughout the genome of both males and females, but no appreciable accumulation or differentiation of these types of sequences have been found in the Y chromosomes. These repetitive DNA sequences are more conserved in the genome of other dioecious species such as Rumex papillaris, Rumex intermedius, Rumex thyrsoides, Rumex hastatulus, and Rumex suffruticosus, than in the polygamous, gynodioecious, or hermaphrodite species Rumex induratus, Rumex lunaria, Rumex con glom er atus, Rumex crispus, and Rumex bucephalo phorus, which supports a single origin of dioecious species in this genus. The implication of these transposable elements in the origin and evolution of the heteromorphic sex chromosomes of R. acetosa is discussed.

  20. The Daxx/Atrx Complex Protects Tandem Repetitive Elements during DNA Hypomethylation by Promoting H3K9 Trimethylation.

    Science.gov (United States)

    He, Quanyuan; Kim, Hyeung; Huang, Rui; Lu, Weisi; Tang, Mengfan; Shi, Fengtao; Yang, Dong; Zhang, Xiya; Huang, Junjiu; Liu, Dan; Songyang, Zhou

    2015-09-03

    In mammals, DNA methylation is essential for protecting repetitive sequences from aberrant transcription and recombination. In some developmental contexts (e.g., preimplantation embryos) DNA is hypomethylated but repetitive elements are not dysregulated, suggesting that alternative protection mechanisms exist. Here we explore the processes involved by investigating the role of the chromatin factors Daxx and Atrx. Using genome-wide binding and transcriptome analysis, we found that Daxx and Atrx have distinct chromatin-binding profiles and are co-enriched at tandem repetitive elements in wild-type mouse ESCs. Global DNA hypomethylation further promoted recruitment of the Daxx/Atrx complex to tandem repeat sequences, including retrotransposons and telomeres. Knockdown of Daxx/Atrx in cells with hypomethylated genomes exacerbated aberrant transcriptional de-repression of repeat elements and telomere dysfunction. Mechanistically, Daxx/Atrx-mediated repression seems to involve Suv39h recruitment and H3K9 trimethylation. Our data therefore suggest that Daxx and Atrx safeguard the genome by silencing repetitive elements when DNA methylation levels are low.

  1. Competitive repair by naturally dispersed repetitive DNA during non-allelic homologous recombination

    Energy Technology Data Exchange (ETDEWEB)

    Hoang, Margaret L.; Tan, Frederick J.; Lai, David C.; Celniker, Sue E.; Hoskins, Roger A.; Dunham, Maitreya J.; Zheng, Yixian; Koshland, Douglas

    2010-08-27

    Genome rearrangements often result from non-allelic homologous recombination (NAHR) between repetitive DNA elements dispersed throughout the genome. Here we systematically analyze NAHR between Ty retrotransposons using a genome-wide approach that exploits unique features of Saccharomyces cerevisiae purebred and Saccharomyces cerevisiae/Saccharomyces bayanus hybrid diploids. We find that DNA double-strand breaks (DSBs) induce NAHR-dependent rearrangements using Ty elements located 12 to 48 kilobases distal to the break site. This break-distal recombination (BDR) occurs frequently, even when allelic recombination can repair the break using the homolog. Robust BDR-dependent NAHR demonstrates that sequences very distal to DSBs can effectively compete with proximal sequences for repair of the break. In addition, our analysis of NAHR partner choice between Ty repeats shows that intrachromosomal Ty partners are preferred despite the abundance of potential interchromosomal Ty partners that share higher sequence identity. This competitive advantage of intrachromosomal Tys results from the relative efficiencies of different NAHR repair pathways. Finally, NAHR generates deleterious rearrangements more frequently when DSBs occur outside rather than within a Ty repeat. These findings yield insights into mechanisms of repeat-mediated genome rearrangements associated with evolution and cancer.

  2. Variability and evolutionary implications of repetitive DNA dynamics in genome of Astyanax scabripinnis (Teleostei, Characidae)

    Science.gov (United States)

    Barbosa, Patrícia; Leal, Eliza Viola; da Silva, Maelin; de Almeida, Mara Cristina; Moreira-Filho, Orlando; Artoni, Roberto Ferreira

    2017-01-01

    Abstract DNA sequences of multiple copies help in understanding evolutionary mechanisms, genomic structures and karyotype differentiation. The current study investigates the organization and distribution of different repetitive DNA in the standard complement and B chromosomes in Astyanax scabripinnis (Jenyns, 1842) chromosomes from three allopatric populations in Campos do Jordão region, São Paulo State, Brazil. The location of microsatellite sequences showed different chromosome distribution between Lavrinha Farm Stream (LFS) and Lake of Pedalinho (LP) populations. However, the karyotype of these populations basically followed the pattern of dispersed distribution in the A complement, conspicuous in telomeric/interstitial regions and preferential accumulation in the B chromosome. The B chromosome showed heterogeneous location of microsatellite probes CA, CAC and GA. The H3 and H4 histone genes were isolated from the total genome of the species and then the chromosomal mapping was performed by fluorescence in situ hybridization (FISH). The FISH signals showed high similarity for the probes H3 and H4 mapping in genomes of the populations analyzed. The sequences (GATA)n revealed a sex-specific trend between the chromosomal location in males and females at (LFS) and (LP) populations. Although species that comprise the Astyanax scabripinnis complex do not have morphologically differentiated sex chromosomes, the preferential GATA location – sex-associated – may represent a sex chromosome in differentiation. PMID:28919955

  3. Bacterial repetitive extragenic palindromic sequences are DNA targets for Insertion Sequence elements

    Directory of Open Access Journals (Sweden)

    Pareja Eduardo

    2006-03-01

    Full Text Available Abstract Background Mobile elements are involved in genomic rearrangements and virulence acquisition, and hence, are important elements in bacterial genome evolution. The insertion of some specific Insertion Sequences had been associated with repetitive extragenic palindromic (REP elements. Considering that there are a sufficient number of available genomes with described REPs, and exploiting the advantage of the traceability of transposition events in genomes, we decided to exhaustively analyze the relationship between REP sequences and mobile elements. Results This global multigenome study highlights the importance of repetitive extragenic palindromic elements as target sequences for transposases. The study is based on the analysis of the DNA regions surrounding the 981 instances of Insertion Sequence elements with respect to the positioning of REP sequences in the 19 available annotated microbial genomes corresponding to species of bacteria with reported REP sequences. This analysis has allowed the detection of the specific insertion into REP sequences for ISPsy8 in Pseudomonas syringae DC3000, ISPa11 in P. aeruginosa PA01, ISPpu9 and ISPpu10 in P. putida KT2440, and ISRm22 and ISRm19 in Sinorhizobium meliloti 1021 genome. Preference for insertion in extragenic spaces with REP sequences has also been detected for ISPsy7 in P. syringae DC3000, ISRm5 in S. meliloti and ISNm1106 in Neisseria meningitidis MC58 and Z2491 genomes. Probably, the association with REP elements that we have detected analyzing genomes is only the tip of the iceberg, and this association could be even more frequent in natural isolates. Conclusion Our findings characterize REP elements as hot spots for transposition and reinforce the relationship between REP sequences and genomic plasticity mediated by mobile elements. In addition, this study defines a subset of REP-recognizer transposases with high target selectivity that can be useful in the development of new tools for

  4. Stem-loop structures of the repetitive DNA sequences located at human centromeres

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, G.; Garcia, A.E.; Ratliff, R.; Moyzis, R.K. [Los Alamos National Lab., NM (United States); Catasti, P.; Hong, Lin; Yau, P. [California Univ., Davis, CA (United States). Dept. of Biological Chemistry; Bradbury, E.M. [Los Alamos National Lab., NM (United States)]|[California Univ., Davis, CA (United States). Dept. of Biological Chemistry

    1993-09-01

    The presence of the highly conserved repetitive DNA sequences in the human centromeres argues for a special role of these sequences in their biological functions - most likely achieved by the formation of unusual structures. This prompted us to carry out quantitative one- and two-dimensional nuclear magnetic resonance (lD/2D NMR) spectroscopy to determine the structural properties of the human centromeric repeats, d(AATGG){sub n.d}(CCATT){sub n}. The studies on centromeric DNAs reveal that the complementary sequence, d(AATGG){sub n.d}(CCATT){sub n}, adopts the usual Watson-Crick B-DNA duplex and the pyrimidine-rich d(CCATT){sub n} strand is essentially a random coil. However, the purine-rich d(AATGG){sub n} strand is shown to adopt unusual stem-loop structures for repeat lengths, n=2,3,4, and 6. In addition to normal Watson-Crick A{center_dot}T pairs, the stem-loop structures are stabilized by mismatch A{center_dot}G and G{center_dot}G pairs in the stem and G-G-A stacking in the loop. Stem-loop structures of d(AATGG)n are independently verified by gel electrophoresis and nuclease digestion studies. Thermal melting studies show that the DNA repeats, d(AATGG){sub n}, are as stable as the corresponding Watson-Crick duplex d(AATGG){sub n.d}(CCATT){sub n}. Therefore, the sequence d(AATGG){sub n} can, indeed, nucleate a stem-loop structure at little free-energy cost and if, during mitosis, they are located on the chromosome surface they can provide specific recognition sites for kinetochore function.

  5. Molecular cytogenetic mapping of Cucumis sativus and C. melo using highly repetitive DNA sequences.

    Science.gov (United States)

    Koo, Dal-Hoe; Nam, Young-Woo; Choi, Doil; Bang, Jae-Wook; de Jong, Hans; Hur, Yoonkang

    2010-04-01

    Chromosomes often serve as one of the most important molecular aspects of studying the evolution of species. Indeed, most of the crucial mutations that led to differentiation of species during the evolution have occurred at the chromosomal level. Furthermore, the analysis of pachytene chromosomes appears to be an invaluable tool for the study of evolution due to its effectiveness in chromosome identification and precise physical gene mapping. By applying fluorescence in situ hybridization of 45S rDNA and CsCent1 probes to cucumber pachytene chromosomes, here, we demonstrate that cucumber chromosomes 1 and 2 may have evolved from fusions of ancestral karyotype with chromosome number n = 12. This conclusion is further supported by the centromeric sequence similarity between cucumber and melon, which suggests that these sequences evolved from a common ancestor. It may be after or during speciation that these sequences were specifically amplified, after which they diverged and specific sequence variants were homogenized. Additionally, a structural change on the centromeric region of cucumber chromosome 4 was revealed by fiber-FISH using the mitochondrial-related repetitive sequences, BAC-E38 and CsCent1. These showed the former sequences being integrated into the latter in multiple regions. The data presented here are useful resources for comparative genomics and cytogenetics of Cucumis and, in particular, the ongoing genome sequencing project of cucumber.

  6. Molecular cytogenetics of Alstroemeria: identification of parental genomes in interspecific hybrids and characterization of repetitive DNA families in constitutive heterochromatin.

    Science.gov (United States)

    Kuipers, A G; van Os, D P; de Jong, J H; Ramanna, M S

    1997-02-01

    The genus Alstroemeria consists of diploid (2n = 2x = 16) species originating mainly from Chile and Brazil. Most cultivars are triploid or tetraploid interspecific hybrids. C-banding of eight species revealed obvious differentiation of constitutive heterochromatin within the genus. The present study focused on the molecular (cyto)genetic background of this differentiation. Genomic slot-blot analysis demonstrated strong conservation of major parts of the genomes among six species. The chromosomes of A. aurea and A. ligtu, species with pronounced interstitial C-bands, were found to contain large amounts of highly repetitive and species-specific DNA. The variation in size, number and intensity of strongly probed bands of major repetitive DNA families observed in genomic Southern blots of Sau3A, HaeIII, and MseI digests indicated a strong correlation between variation in genomic DNA composition and different C-banding patterns among Alstroemeria species. Genomic in situ hybridization (GISH) revealed a clear distinction between parental chromosomes in the hybrids between Chilean and Brazilian species and also between Chilean species, as long as at least one of the parental species possessed prominent C-banding. Regarding the latter, discriminative hybridization resulted from highly repetitive species specific DNA in the heterochromatic chromosome regions of A. aurea and A. ligtu, and caused GISH banding patterns that coincided with the C-banding patterns.

  7. Identification and chromosome mapping of repetitive elements in the Astyanax scabripinnis (Teleostei: Characidae) species complex.

    Science.gov (United States)

    Barbosa, Patrícia; de Oliveira, Luiz Antonio; Pucci, Marcela Baer; Santos, Mateus Henrique; Moreira-Filho, Orlando; Vicari, Marcelo Ricardo; Nogaroto, Viviane; de Almeida, Mara Cristina; Artoni, Roberto Ferreira

    2015-02-01

    Most part of the eukaryotic genome is composed of repeated sequences or multiple copies of DNA, which were considered as "junk DNA", and may be associated to the heterochromatin. In this study, three populations of Astyanax aff. scabripinnis from Brazilian rivers of Guaratinguetá and Pindamonhangaba (São Paulo) and a population from Maringá (Paraná) were analyzed concerning the localization of the nucleolar organizer regions (Ag-NORs), the As51 satellite DNA, the 18S ribosomal DNA (rDNA), and the 5S rDNA. Repeated sequences were also isolated and identified by the Cot - 1 method, which indicated similarity (90%) with the LINE UnaL2 retrotransposon. The fluorescence in situ hybridization (FISH) showed the retrotransposon dispersed and more concentrated markers in centromeric and telomeric chromosomal regions. These sequences were co-localized and interspaced with 18S and 5S rDNA and As51, confirmed by fiber-FISH essay. The B chromosome found in these populations pointed to a conspicuous hybridization with LINE probe, which is also co-located in As51 sequences. The NORs were active at unique sites of a homologous pair in the three populations. There were no evidences that transposable elements and repetitive DNA had influence in the transcriptional regulation of ribosomal genes in our analyses.

  8. Comparison of the distribution of the repetitive DNA sequences in three variants of Cucumis sativus reveals their phylogenetic relationships.

    Science.gov (United States)

    Zhao, Xin; Lu, Jingyuan; Zhang, Zhonghua; Hu, Jiajin; Huang, Sanwen; Jin, Weiwei

    2011-01-01

    Repetitive DNA sequences with variability in copy number or/and sequence polymorphism can be employed as useful molecular markers to study phylogenetics and identify species/chromosomes when combined with fluorescence in situ hybridization (FISH). Cucumis sativus has three variants, Cucumis sativus L. var. sativus, Cucumis sativus L. var. hardwickii and Cucumis sativus L. var. xishuangbannesis. The phylogenetics among these three variants has not been well explored using cytological landmarks. Here, we concentrate on the organization and distribution of highly repetitive DNA sequences in cucumbers, with emphasis on the differences between cultivar and wild cucumber. The diversity of chromosomal karyotypes in cucumber and its relatives was detected in our study. Thereby, sequential FISH with three sets of multi-probe cocktails (combined repetitive DNA with chromosome-specific fosmid clones as probes) were conducted on the same metaphase cell, which helped us to simultaneously identify each of the 7 metaphase chromosomes of wild cucumber C. sativus var. hardwickii. A standardized karyotype of somatic metaphase chromosomes was constructed. Our data also indicated that the relationship between cultivar cucumber and C. s. var. xishuangbannesis was closer than that of C. s. var. xishuangbannesis and C. s. var. hardwickii.

  9. Comparison of the distribution of the repetitive DNA sequences in three variants of Cucumis sativus reveals their phylogenetic relationships

    Institute of Scientific and Technical Information of China (English)

    Xin Zhao; Jingyuan Lu; Zhonghua Zhang; Jiajin Hu; Sanwen Huang; Weiwei Jin

    2011-01-01

    Repetitive DNA sequences with variability in copy number or/and sequence polymorphism can be employed as useful molecular markers to study phylogenetics and identify species/chromosomes when combined with fluorescence in situ hybridization (FISH). Cucumis sativus has three variants, Cucumis sativus L. var. sativus, Cucumis sativus L. var. hardwickii and Cucumis sativus L. var. xishuangbannesis. The phylogenetics among these three variants has not been well explored using cytological landmarks. Here, we concentrate on the organization and distribution of highly repetitive DNA sequences in cucumbers, with emphasis on the differences between cultivar and wild cucumber. The diversity of chromosomal karyotypes in cucumber and its relatives was detected in our study. Thereby, sequential FISH with three sets of multi-probe cocktails (combined repetitive DNA with chromosome-specific fosmid clones as probes) were conducted on the same metaphase cell, which helped us to simultaneously identify each of the 7 metaphase chromosomes of wild cucumber C. sativus var. hardwickii. A standardized karyotype of somatic metaphase chromosomes was constructed. Our data also indicated that the relationship between cultivar cucumber and C. s.var. xishuangbannesis was closer than that of C. s. var. xishuangbannesis and C. s. var. hardwickii.

  10. S1 satellite DNA repetitive units display identical structure and overall variability in all Anatolian brown frog taxa.

    Science.gov (United States)

    Picariello, Orfeo; Feliciello, Isidoro; Chinali, Gianni

    2016-02-01

    S1 satellite DNA from Palearctic brown frogs has a species-specific structure in all European species. We characterized S1 satellite DNA from the Anatolian brown frogs Rana macrocnemis, R. camerani, and R. holtzi in order to define their taxonomic rank and the structure of this satellite in this frog lineage. Southern blots of genomic DNA digested with KpnI, EcoRV, NdeI, NheI, or StuI produced the same pattern of satellite DNA bands. Moreover, quantitative dot blots showed that this satellite DNA accounts for 0.1 % of the genome in all taxa. Analysis of the overall genomic variability of the S1a repeat sequence in specimens from various populations demonstrated that this repetitive unit also has the same size (476 bp), the same most common sequence (MCS) and the same overall variability in all three taxa, and also in R. macrocnemis tavasensis. The S1a repetitive unit presents three deletions of 9, 8 and 1 bp compared to the 494-bp S1a repeat from European frogs. The S1a MCS has three variable positions (sequence WWTK in positions 183-186), due to the presence of two repeat subpopulations with motifs AATG and WWTT in all taxa. Unlike previously analyzed mitochondrial and nuclear sequences that show considerable variations among these taxa, no difference could be detected in the structure and variability of the S1 satellite repetitive units. This suggests that these taxa should belong to a single species. Our results indicate that this satellite DNA variety probably formed when the Anatolian lineage radiated from common ancestor about 4 mya, and since then has maintained its structure in all four taxa examined.

  11. Birthweight, maternal weight trajectories and global DNA methylation of LINE-1 repetitive elements.

    Directory of Open Access Journals (Sweden)

    Karin B Michels

    Full Text Available Low birthweight, premature birth, intrauterine growth retardation, and maternal malnutrition have been related to an increased risk of cardiovascular disease, type 2 diabetes mellitus, obesity, and neuropsychiatric disorders later in life. Conversely, high birthweight has been linked to future risk of cancer. Global DNA methylation estimated by the methylation of repetitive sequences in the genome is an indicator of susceptibility to chronic diseases. We used data and biospecimens from an epigenetic birth cohort to explore the association between trajectories of fetal and maternal weight and LINE-1 methylation in 319 mother-child dyads. Newborns with low or high birthweight had significantly lower LINE-1 methylation levels in their cord blood compared to normal weight infants after adjusting for gestational age, sex of the child, maternal age at delivery, and maternal smoking during pregnancy (p = 0.007 and p = 0.036, respectively, but the magnitude of the difference was small. Infants born prematurely also had lower LINE-1 methylation levels in cord blood compared to term infants, and this difference, though small, was statistically significant (p = 0.004. We did not find important associations between maternal prepregnancy BMI or gestational weight gain and global methylation of the cord blood or fetal placental tissue. In conclusion, we found significant differences in cord blood LINE-1 methylation among newborns with low and high birthweight as well as among prematurely born infants. Future studies may elucidate whether chromosomal instabilities or other functional consequences of these changes contribute to the increased risk of chronic diseases among individuals with these characteristics.

  12. Shared Y chromosome repetitive DNA sequences in stallion and donkey as visualized using whole-genomic comparative hybridization

    Directory of Open Access Journals (Sweden)

    R. Mezzanotte

    2010-01-01

    Full Text Available The genome of stallion (Spanish breed and donkey (Spanish endemic Zamorano-Leonés were compared using whole comparative genomic in situ hybridization (W-CGH technique, with special reference to the variability observed in the Y chromosome. Results show that these diverging genomes still share some highly repetitive DNA families localized in pericentromeric regions and, in the particular case of the Y chromosome, a sub-family of highly repeated DNA sequences, greatly expanded in the donkey genome, accounts for a large part of the chromatin in the stallion Y chromosome.

  13. Shared Y chromosome repetitive DNA sequences in stallion and donkey as visualized using whole-genomic comparative hybridization

    Directory of Open Access Journals (Sweden)

    J. Gosalvez

    2010-01-01

    Full Text Available The genome of stallion (Spanish breed and donkey (Spanish endemic Zamorano-Leonés were compared using whole comparative genomic in situ hybridization (W-CGH technique, with special reference to the variability observed in the Y chromosome. Results show that these diverging genomes still share some highly repetitive DNA families localized in pericentromeric regions and, in the particular case of the Y chromosome, a sub-family of highly repeated DNA sequences, greatly expanded in the donkey genome, accounts for a large part of the chromatin in the stallion Y chromosome.

  14. Structural biology of disease-associated repetitive DNA sequences and protein-DNA complexes involved in DNA damage and repair

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, G.; Santhana Mariappan, S.V.; Chen, X.; Catasti, P.; Silks, L.A. III; Moyzis, R.K.; Bradbury, E.M.; Garcia, A.E.

    1997-07-01

    This project is aimed at formulating the sequence-structure-function correlations of various microsatellites in the human (and other eukaryotic) genomes. Here the authors have been able to develop and apply structure biology tools to understand the following: the molecular mechanism of length polymorphism microsatellites; the molecular mechanism by which the microsatellites in the noncoding regions alter the regulation of the associated gene; and finally, the molecular mechanism by which the expansion of these microsatellites impairs gene expression and causes the disease. Their multidisciplinary structural biology approach is quantitative and can be applied to all coding and noncoding DNA sequences associated with any gene. Both NIH and DOE are interested in developing quantitative tools for understanding the function of various human genes for prevention against diseases caused by genetic and environmental effects.

  15. Rapid proliferation of repetitive palindromic elements in mtDNA of the endemic Baikalian sponge Lubomirskia baicalensis.

    Science.gov (United States)

    Lavrov, Dennis V

    2010-04-01

    Animal mitochondrial DNA (mtDNA) is a remarkably compact molecule largely because of the scarcity of noncoding "selfish" DNA. Recently, however, we found that mitochondrial genomes of several phylogenetically diverse species of demosponges contain small repetitive palindromic sequences, interspersed within intergenic regions and fused in protein and ribosomal RNA genes. Here, I report and analyze the proliferation of such elements in the mitochondrial genome of the endemic sponge of Lake Baikal Lubomirskia baicalensis. Because Baikal sponges are closely related to the circumglobally distributed freshwater sponge Ephydatia muelleri with which they shared a common ancestor approximately 3-10 Ma, both the rate of single nucleotide substitutions and the rate of palindromic repeat insertions can be calculated in this system. I found the rate of nucleotide substitutions in mtDNA of freshwater sponges to be extremely low (0.5-1.6 x 10(-9) per site per year), more similar to that in plants than bilaterian animals. By contrast, the per/nucleotide rate of insertions of repetitive elements is at least four times higher. This rapid rate of proliferation combined with the broad phylogenetic distribution of hairpin elements can make them a defining force in the evolution of mitochondrial genomes of demosponges.

  16. Development of two highly sensitive forensic sex determination assays based on human DYZ1 and Alu repetitive DNA elements.

    Science.gov (United States)

    Fazi, Amanda; Gobeski, Brianne; Foran, David

    2014-11-01

    Sex determination is a critical component of forensic identification, the standard genetic method for which is detection of the single copy amelogenin gene that has differing homologues on the X and Y chromosomes. However, this assay may not be sensitive enough when DNA samples are minute or highly compromised, thus other strategies for sex determination are needed. In the current research, two ultrasensitive sexing assays, based on real-time PCR and pyrosequencing, were developed targeting the highly repetitive elements DYZ1 on the Y chromosome and Alu on the autosomes. The DYZ1/Alu strategy was compared to amelogenin for overall sensitivity based on high molecular weight and degraded DNA, followed by assaying the sex of 34 touch DNA samples and DNA from 30 hair shafts. The real-time DYZ1/Alu assay proved to be approximately 1500 times more sensitive than its amelogenin counterpart based on high molecular weight DNA, and even more sensitive when sexing degraded DNA. The pyrosequencing DYZ1/Alu assay correctly sexed 26 of the touch DNAs, compared to six using amelogenin. Hair shaft DNAs showed equally improved sexing results using the DYZ1/Alu assays. Overall, both DYZ1/Alu assays were far more sensitive and accurate than was the amelogenin assay, and thus show great utility for sexing poor quality and low quantity DNA evidence.

  17. Differentiation of the XY sex chromosomes in the fish Hoplias malabaricus (Characiformes, Erythrinidae): unusual accumulation of repetitive sequences on the X chromosome.

    Science.gov (United States)

    Cioffi, M B; Martins, C; Vicari, M R; Rebordinos, L; Bertollo, L A C

    2010-01-01

    The wolf fish Hoplias malabaricus (Erythrinidae) presents a high karyotypic diversity, with 7 karyomorphs identified. Karyomorph A is characterized by 2n = 42 chromosomes, without morphologically differentiated sex chromosomes. Karyomorph B also has 2n = 42 chromosomes for both sexes, but differs by a distinct heteromorphic XX/XY sex chromosome system. The cytogenetic mapping of 5 classes of repetitive DNA indicated similarities between both karyomorphs and the probable derivation of the XY chromosomes from pair No. 21 of karyomorph A. These chromosomes appear to be homeologous since the distribution of (GATA)(n) sequences, 18S rDNA and 5SHindIII-DNA sites supports their potential relatedness. Our data indicate that the differentiation of the long arms of the X chromosome occurred by accumulation of heterochromatin and 18S rDNA cistrons from the ancestral homomorphic pair No. 21 present in karyomorph A. These findings are further supported by the distribution of the Cot-1 DNA fraction. In addition, while the 18S rDNA cistrons were maintained and amplified on the X chromosomes, they were lost in the Y chromosome. The X chromosome was a clearly preferred site for the accumulation of DNA repeats, representing an unusual example of an X clustering more repetitive sequences than the Y during sex chromosome differentiation in fish.

  18. The mitochondrial and plastid genomes of Volvox carteri: bloated molecules rich in repetitive DNA

    Directory of Open Access Journals (Sweden)

    Lee Robert W

    2009-03-01

    Full Text Available Abstract Background The magnitude of noncoding DNA in organelle genomes can vary significantly; it is argued that much of this variation is attributable to the dissemination of selfish DNA. The results of a previous study indicate that the mitochondrial DNA (mtDNA of the green alga Volvox carteri abounds with palindromic repeats, which appear to be selfish elements. We became interested in the evolution and distribution of these repeats when, during a cursory exploration of the V. carteri nuclear DNA (nucDNA and plastid DNA (ptDNA sequences, we found palindromic repeats with similar structural features to those of the mtDNA. Upon this discovery, we decided to investigate the diversity and evolutionary implications of these palindromic elements by sequencing and characterizing large portions of mtDNA and ptDNA and then comparing these data to the V. carteri draft nuclear genome sequence. Results We sequenced 30 and 420 kilobases (kb of the mitochondrial and plastid genomes of V. carteri, respectively – resulting in partial assemblies of these genomes. The mitochondrial genome is the most bloated green-algal mtDNA observed to date: ~61% of the sequence is noncoding, most of which is comprised of short palindromic repeats spread throughout the intergenic and intronic regions. The plastid genome is the largest (>420 kb and most expanded (>80% noncoding ptDNA sequence yet discovered, with a myriad of palindromic repeats in the noncoding regions, which have a similar size and secondary structure to those of the mtDNA. We found that 15 kb (~0.01% of the nuclear genome are homologous to the palindromic elements of the mtDNA, and 50 kb (~0.05% are homologous to those of the ptDNA. Conclusion Selfish elements in the form of short palindromic repeats have propagated in the V. carteri mtDNA and ptDNA, resulting in the distension of these genomes. Copies of these same repeats are also found in a small fraction of the nucDNA, but appear to be inert in this

  19. A Twenty-First Century View of Evolution: Genome System Architecture, Repetitive DNA, and Natural Genetic Engineering

    Science.gov (United States)

    Shapiro, James A.

    It is essential for nonbiologists to understand that evolutionary theory based on random mutation of autonomous genes is far from the last word on how genomes have changed in the course of biological evolution. The last 50 years of molecular genetics have produced an abundance of new discoveries and data that make it useful to revisit some basic concepts and assumptions in our thinking about genomes and evolution. Chief among these observations are the complex modularity of genome organization, the biological ubiquity of mobile and repetitive DNA sequences, and the fundamental importance of DNA rearrangements in the evolution of sequenced genomes. This review will take a broad overview of these developments and suggest some new ways of thinking about genomes as sophisticated informatic storage systems and about evolution as a systems engineering process.

  20. Genomic Organization of Repetitive DNA Elements and Its Implications for the Chromosomal Evolution of Channid Fishes (Actinopterygii, Perciformes)

    Science.gov (United States)

    Cioffi, Marcelo de Bello; Bertollo, Luiz Antonio Carlos; Villa, Mateo Andres; de Oliveira, Ezequiel Aguiar; Tanomtong, Alongklod; Yano, Cassia Fernanda; Supiwong, Weerayuth; Chaveerach, Arunrat

    2015-01-01

    Channid fishes, commonly referred to as “snakeheads”, are currently very important in Asian fishery and aquaculture due to the substantial decline in natural populations because of overexploitation. A large degree of chromosomal variation has been found in this family, mainly through the use of conventional cytogenetic investigations. In this study, we analyzed the karyotype structure and the distribution of 7 repetitive DNA sequences in several Channa species from different Thailand river basins. The aim of this study was to investigate the chromosomal differentiation among species and populations to improve upon the knowledge of its biodiversity and evolutionary history. Rearrangements, such as pericentric inversions, fusions and polyploidization, appear to be important events during the karyotypic evolution of this genus, resulting in the chromosomal diversity observed among the distinct species and even among populations of the same species. In addition, such variability is also increased by the genomic dynamism of repetitive elements, particularly by the differential distribution and accumulation of rDNA sequences on chromosomes. This marked diversity is likely linked to the lifestyle of the snakehead fishes and their population fragmentation, as already identified for other fish species. The karyotypic features highlight the biodiversity of the channid fishes and justify a taxonomic revision of the genus Channa, as well as of the Channidae family as a whole, as some nominal species may actually constitute species complexes. PMID:26067030

  1. Genomic Organization of Repetitive DNA Elements and Its Implications for the Chromosomal Evolution of Channid Fishes (Actinopterygii, Perciformes.

    Directory of Open Access Journals (Sweden)

    Marcelo de Bello Cioffi

    Full Text Available Channid fishes, commonly referred to as "snakeheads", are currently very important in Asian fishery and aquaculture due to the substantial decline in natural populations because of overexploitation. A large degree of chromosomal variation has been found in this family, mainly through the use of conventional cytogenetic investigations. In this study, we analyzed the karyotype structure and the distribution of 7 repetitive DNA sequences in several Channa species from different Thailand river basins. The aim of this study was to investigate the chromosomal differentiation among species and populations to improve upon the knowledge of its biodiversity and evolutionary history. Rearrangements, such as pericentric inversions, fusions and polyploidization, appear to be important events during the karyotypic evolution of this genus, resulting in the chromosomal diversity observed among the distinct species and even among populations of the same species. In addition, such variability is also increased by the genomic dynamism of repetitive elements, particularly by the differential distribution and accumulation of rDNA sequences on chromosomes. This marked diversity is likely linked to the lifestyle of the snakehead fishes and their population fragmentation, as already identified for other fish species. The karyotypic features highlight the biodiversity of the channid fishes and justify a taxonomic revision of the genus Channa, as well as of the Channidae family as a whole, as some nominal species may actually constitute species complexes.

  2. Genomic Organization of Repetitive DNA in Woodpeckers (Aves, Piciformes): Implications for Karyotype and ZW Sex Chromosome Differentiation.

    Science.gov (United States)

    de Oliveira, Thays Duarte; Kretschmer, Rafael; Bertocchi, Natasha Avila; Degrandi, Tiago Marafiga; de Oliveira, Edivaldo Herculano Corrêa; Cioffi, Marcelo de Bello; Garnero, Analía Del Valle; Gunski, Ricardo José

    2017-01-01

    Birds are characterized by a low proportion of repetitive DNA in their genome when compared to other vertebrates. Among birds, species belonging to Piciformes order, such as woodpeckers, show a relatively higher amount of these sequences. The aim of this study was to analyze the distribution of different classes of repetitive DNA-including microsatellites, telomere sequences and 18S rDNA-in the karyotype of three Picidae species (Aves, Piciformes)-Colaptes melanochloros (2n = 84), Colaptes campestris (2n = 84) and Melanerpes candidus (2n = 64)-by means of fluorescence in situ hybridization. Clusters of 18S rDNA were found in one microchromosome pair in each of the three species, coinciding to a region of (CGG)10 sequence accumulation. Interstitial telomeric sequences were found in some macrochromosomes pairs, indicating possible regions of fusions, which can be related to variation of diploid number in the family. Only one, from the 11 different microsatellite sequences used, did not produce any signals. Both species of genus Colaptes showed a similar distribution of microsatellite sequences, with some difference when compared to M. candidus. Microsatellites were found preferentially in the centromeric and telomeric regions of micro and macrochromosomes. However, some sequences produced patterns of interstitial bands in the Z chromosome, which corresponds to the largest element of the karyotype in all three species. This was not observed in the W chromosome of Colaptes melanochloros, which is heterochromatic in most of its length, but was not hybridized by any of the sequences used. These results highlight the importance of microsatellite sequences in differentiation of sex chromosomes, and the accumulation of these sequences is probably responsible for the enlargement of the Z chromosome.

  3. Phylogeny of Trypanosoma brucei and Trypanosoma evansi in naturally infected cattle in Nigeria by analysis of repetitive and ribosomal DNA sequences.

    Science.gov (United States)

    Takeet, Michael I; Peters, Sunday O; Fagbemi, Benjamin O; De Donato, Marcos; Takeet, Vivian O; Wheto, Mathew; Imumorin, Ikhide G

    2016-08-01

    In continuing efforts to better understand the genetics of bovine trypanosomosis, we assessed genetic diversity of Trypanosoma brucei and Trypanosoma evansi in naturally infected Nigerian cattle using repetitive DNA and internal transcribed spacer 1 of rDNA sequences and compared these sequences to species from other countries. The length of repetitive DNA sequences in both species ranged from 161 to 244 bp and 239 to 240 bp for T. brucei and T. evansi, respectively, while the ITS1 rDNA sequences length range from 299 to 364 bp. The mean GC content of ITS1 rDNA sequences was 33.57 %, and that of repetitive sequences were 39.9 and 31.1 % for T. brucei and T. evansi, respectively. Result from sequence alignment revealed both T. brucei and T. evansi repetitive DNA sequences to be more polymorphic than ITS1 rDNA sequences, with moderate points of deletion and insertions. T. brucei separated into two clades when subjected to phylogenetic analysis. T. evansi repetitive DNA sequences clustered tightly within the T. brucei clade while the ITS1 rDNA sequences of T. brucei were clearly separated from T. theileri and T. vivax individually used as outgroups. This study suggest that ITS1 rDNA sequences may not be suitable for phylogenetic differentiation of the Trypanozoon group and also suggest that T. evansi may be a phenotypic variant of T. brucei which may have potential implications in designing prevention and therapeutic strategies.

  4. By-Product Formation in Repetitive PCR Amplification of DNA Libraries during SELEX

    DEFF Research Database (Denmark)

    Tolle, Fabian; Wilke, Julian; Wengel, Jesper

    2014-01-01

    The selection of nucleic acid aptamers is an increasingly important approach to generate specific ligands binding to virtually any molecule of choice. However, selection-inherent amplification procedures are prone to artificial by-product formation that prohibits the enrichment of target-recogniz......The selection of nucleic acid aptamers is an increasingly important approach to generate specific ligands binding to virtually any molecule of choice. However, selection-inherent amplification procedures are prone to artificial by-product formation that prohibits the enrichment of target......-recognizing aptamers. Little is known about the formation of such by-products when employing nucleic acid libraries as templates. We report on the formation of two different forms of by-products, named ladder- and non-ladder-type observed during repetitive amplification in the course of in vitro selection experiments...

  5. LINE-1 repetitive DNA probes for species-specific cloning from Mus spretus and Mus domesticus genomes.

    Science.gov (United States)

    Rikke, B A; Hardies, S C

    1991-12-01

    Mus domesticus and Mus spretus mice are closely related subspecies. For genetic investigations involving hybrid mice, we have developed a set of species-specific oligonucleotide probes based on the detection of LINE-1 sequence differences. LINE-1 is a repetitive DNA family whose many members are interspersed among the genes. In this study, library screening experiments were used to fully characterize the species specificity of four M. domesticus LINE-1 probes and three M. spretus LINE-1 probes. It was found that the nucleotide differences detected by the probes define large, species-specific subfamilies. We show that collaborative use of such probes can be employed to selectively detect thousands of species-specific library clones. Consequently, these probes could be exploited to monitor and access almost any given species-specific region of interest within hybrid genomes.

  6. Deep investigation of Arabidopsis thaliana junk DNA reveals a continuum between repetitive elements and genomic dark matter.

    Science.gov (United States)

    Maumus, Florian; Quesneville, Hadi

    2014-01-01

    Eukaryotic genomes contain highly variable amounts of DNA with no apparent function. This so-called junk DNA is composed of two components: repeated and repeat-derived sequences (together referred to as the repeatome), and non-annotated sequences also known as genomic dark matter. Because of their high duplication rates as compared to other genomic features, transposable elements are predominant contributors to the repeatome and the products of their decay is thought to be a major source of genomic dark matter. Determining the origin and composition of junk DNA is thus important to help understanding genome evolution as well as host biology. In this study, we have used a combination of tools enabling to show that the repeatome from the small and reducing A. thaliana genome is significantly larger than previously thought. Furthermore, we present the concepts and results from a series of innovative approaches suggesting that a significant amount of the A. thaliana dark matter is of repetitive origin. As a tentative standard for the community, we propose a deep compendium annotation of the A. thaliana repeatome that may help addressing farther genome evolution as well as transcriptional and epigenetic regulation in this model plant.

  7. Genomic Organization of Repetitive DNA in Woodpeckers (Aves, Piciformes): Implications for Karyotype and ZW Sex Chromosome Differentiation

    Science.gov (United States)

    Kretschmer, Rafael; Bertocchi, Natasha Avila; Degrandi, Tiago Marafiga; de Oliveira, Edivaldo Herculano Corrêa; Cioffi, Marcelo de Bello; Garnero, Analía del Valle; Gunski, Ricardo José

    2017-01-01

    Birds are characterized by a low proportion of repetitive DNA in their genome when compared to other vertebrates. Among birds, species belonging to Piciformes order, such as woodpeckers, show a relatively higher amount of these sequences. The aim of this study was to analyze the distribution of different classes of repetitive DNA—including microsatellites, telomere sequences and 18S rDNA—in the karyotype of three Picidae species (Aves, Piciformes)—Colaptes melanochloros (2n = 84), Colaptes campestris (2n = 84) and Melanerpes candidus (2n = 64)–by means of fluorescence in situ hybridization. Clusters of 18S rDNA were found in one microchromosome pair in each of the three species, coinciding to a region of (CGG)10 sequence accumulation. Interstitial telomeric sequences were found in some macrochromosomes pairs, indicating possible regions of fusions, which can be related to variation of diploid number in the family. Only one, from the 11 different microsatellite sequences used, did not produce any signals. Both species of genus Colaptes showed a similar distribution of microsatellite sequences, with some difference when compared to M. candidus. Microsatellites were found preferentially in the centromeric and telomeric regions of micro and macrochromosomes. However, some sequences produced patterns of interstitial bands in the Z chromosome, which corresponds to the largest element of the karyotype in all three species. This was not observed in the W chromosome of Colaptes melanochloros, which is heterochromatic in most of its length, but was not hybridized by any of the sequences used. These results highlight the importance of microsatellite sequences in differentiation of sex chromosomes, and the accumulation of these sequences is probably responsible for the enlargement of the Z chromosome. PMID:28081238

  8. Molecular Cloning and Analysis of a DNA Repetitive Element from the Mouse Genome

    Science.gov (United States)

    Geisinger, Adriana; Cossio, Gabriela; Wettstein, Rodolfo

    2006-01-01

    We report the development of a 3-week laboratory activity for an undergraduate molecular biology course. This activity introduces students to the practice of basic molecular techniques such as restriction enzyme digestion, agarose gel electrophoresis, cloning, plasmid DNA purification, Southern blotting, and sequencing. Students learn how to carry…

  9. Cloning and characterization of a repetitive DNA sequence specific for Trichomonas vaginalis.

    Science.gov (United States)

    Paces, J; Urbánková, V; Urbánek, P

    1992-09-01

    A family of 650-bp-long repeats from the Trichomonas vaginalis genome, designated the Tv-E650 family, was cloned and sequenced. The nucleotide sequence is A+T-rich (73.3% A+T in the consensus sequence) and highly conserved among the 8 molecular clones analyzed. The differences among the clones are single-nucleotide and 2-nucleotide substitutions and insertions or deletions. The sequence uniformity of the clones as well as the presence of identical mutations in different clones suggest that efficient sequence homogenization mechanisms, such as gene conversion or recurring unequal crossing-over, operate in T. vaginalis. The copy number of the Tv-E650 repeats was estimated to be about 10(2)-10(3) per genome. Based on the DNA hybridization results, the Tv-E650 repeat family is conserved in all T. vaginalis strains examined, regardless of their diverse geographical origin. No hybridization of the Tv-E650 probe was found with the DNA from Trichomonas tenax, Trichomonas gallinae and Pentatrichomonas hominis, indicating that the Tv-E650 repeated sequences are species-specific. A dot blot hybridization protocol was developed which does not require isolation of DNA. By using this protocol it was possible to detect the DNA released from approximately 10(3) T. vaginalis cells per dot. These observations suggest that the Tv-E650 probe is potentially applicable to the identification and detection of T. vaginalis.

  10. Rapid development of PCR-based genome-specific repetitive DNA junction markers in wheat

    Science.gov (United States)

    In hexaploid wheat (Triticum aestivum L.) (AABBDD, C=17,000Mb), repeat DNA accounts for ~ 90% of the genome of which transposable elements (TEs) constitute 60-80 %. Despite the dynamic evolution of TEs, our previous study indicated that the majority of TEs between the homologous wheat genomes are co...

  11. Mycoplasma pneumoniae large DNA repetitive elements RepMP1 show type specific organization among strains.

    Directory of Open Access Journals (Sweden)

    Oxana Musatovova

    Full Text Available Mycoplasma pneumoniae is the smallest self-replicating bacterium with a streamlined genome of 0.81 Mb. Complete genome analysis revealed the presence of multiple copies of four large repetitive elements (designated RepMP1, RepMP2/3, RepMP4 and RepMP5 that are implicated in creating sequence variations among individual strains. Recently, we described RepMP1-associated sequence variations between reference strain M129 and clinical isolate S1 that involved three RepMP1-genes (i.e. mpn130, mpn137 and mpn138. Using PCR and sequencing we analyze 28 additional M. pneumoniae strains and demonstrate the existence of S1-like sequence variants in nine strains and M129-like variants in the remaining nineteen strains. We propose a series of recombination steps that facilitates transition from M129- to S1-like sequence variants. Next we examined the remaining RepMP1-genes and observed no other rearrangements related to the repeat element. The only other detected difference was varying numbers of the 21-nucleotide tandem repeats within mpn127, mpn137, mpn501 and mpn524. Furthermore, typing of strains through analysis of large RepMPs localized within the adhesin P1 operon revealed that sequence divergence involving RepMP1-genes mpn130, mpn137 and mpn138 is strictly type-specific. Once more our analysis confirmed existence of two highly conserved groups of M. pneumoniae strains.

  12. [Fluorescence in situ hybridization with DNA probes derived from individual chromosomes and chromosome regions].

    Science.gov (United States)

    Bogomolov, A G; Karamysheva, T V; Rubtsov, N B

    2014-01-01

    A significant part of the eukaryotic genomes consists of repetitive DNA, which can form large clusters or distributed along euchromatic chromosome regions. Repeats located in chromosomal regions make a problem in analysis and identification of the chromosomal material with fluorescence in situ hybridization (FISH). In most cases, the identification of chromosome regions using FISH requires detection of the signal produced with unique sequences. The feasibility, advantages and disadvantages of traditional methods of suppression of repetitive DNA hybridization, methods of repeats-free probe construction and methods of chromosome-specific DNA sequences visualization using image processing of multicolor FISH results are considered in the paper. The efficiency of different techniques for DNA probe generation, different FISH protocols, and image processing of obtained microscopic images depends on the genomic size and structure of analyzing species. This problem was discussed and different approaches were considered for the analysis of the species with very large genome, rare species and species which specimens are too small in size to obtain the amount of genomic and Cot-1 DNA required for suppression of repetitive DNA hybridization.

  13. Condensin suppresses recombination and regulates double-strand break processing at the repetitive ribosomal DNA array to ensure proper chromosome segregation during meiosis in budding yeast

    Science.gov (United States)

    Li, Ping; Jin, Hui; Yu, Hong-Guo

    2014-01-01

    During meiosis, homologues are linked by crossover, which is required for bipolar chromosome orientation before chromosome segregation at anaphase I. The repetitive ribosomal DNA (rDNA) array, however, undergoes little or no meiotic recombination. Hyperrecombination can cause chromosome missegregation and rDNA copy number instability. We report here that condensin, a conserved protein complex required for chromosome organization, regulates double-strand break (DSB) formation and repair at the rDNA gene cluster during meiosis in budding yeast. Condensin is highly enriched at the rDNA region during prophase I, released at the prophase I/metaphase I transition, and reassociates with rDNA before anaphase I onset. We show that condensin plays a dual role in maintaining rDNA stability: it suppresses the formation of Spo11-mediated rDNA breaks, and it promotes DSB processing to ensure proper chromosome segregation. Condensin is unnecessary for the export of rDNA breaks outside the nucleolus but required for timely repair of meiotic DSBs. Our work reveals that condensin coordinates meiotic recombination with chromosome segregation at the repetitive rDNA sequence, thereby maintaining genome integrity. PMID:25103240

  14. Feline Non-repetitive Mitochondrial DNA Control Region Database for Forensic Evidence

    Science.gov (United States)

    Grahn, R. A.; Kurushima, J. D.; Billings, N. C.; Grahn, J.C.; Halverson, J. L.; Hammer, E.; Ho, C.K.; Kun, T. J.; Levy, J.K.; Lipinski, M. J.; Mwenda, J.M.; Ozpinar, H.; Schuster, R.K; Shoorijeh, S.J.; Tarditi, C. R.; Waly, N.E.; Wictum, E. J.; Lyons, L. A.

    2010-01-01

    The domestic cat is the one of the most popular pets throughout the world. A by-product of owning, interacting with, or being in a household with a cat is the transfer of shed fur to clothing or personal objects. As trace evidence, transferred cat fur is a relatively untapped resource for forensic scientists. Both phenotypic and genotypic characteristics can be obtained from cat fur, but databases for neither aspect exist. Because cats incessantly groom, cat fur may have nucleated cells, not only in the hair bulb, but also as epithelial cells on the hair shaft deposited during the grooming process, thereby generally providing material for DNA profiling. To effectively exploit cat hair as a resource, representative databases must be established. This study evaluates 402 bp of the mtDNA control region (CR) from 1,394 cats, including cats from 25 distinct worldwide populations and 26 breeds. Eighty-three percent of the cats are represented by 12 major mitotypes. An additional 8.0% are clearly derived from the major mitotypes. Unique sequences were found in 7.5% of the cats. The overall genetic diversity for this data set was 0.8813 ± 0.0046 with a random match probability of 11.8%. This region of the cat mtDNA has discriminatory power suitable for forensic application worldwide. PMID:20457082

  15. Feline non-repetitive mitochondrial DNA control region database for forensic evidence.

    Science.gov (United States)

    Grahn, R A; Kurushima, J D; Billings, N C; Grahn, J C; Halverson, J L; Hammer, E; Ho, C K; Kun, T J; Levy, J K; Lipinski, M J; Mwenda, J M; Ozpinar, H; Schuster, R K; Shoorijeh, S J; Tarditi, C R; Waly, N E; Wictum, E J; Lyons, L A

    2011-01-01

    The domestic cat is the one of the most popular pets throughout the world. A by-product of owning, interacting with, or being in a household with a cat is the transfer of shed fur to clothing or personal objects. As trace evidence, transferred cat fur is a relatively untapped resource for forensic scientists. Both phenotypic and genotypic characteristics can be obtained from cat fur, but databases for neither aspect exist. Because cats incessantly groom, cat fur may have nucleated cells, not only in the hair bulb, but also as epithelial cells on the hair shaft deposited during the grooming process, thereby generally providing material for DNA profiling. To effectively exploit cat hair as a resource, representative databases must be established. The current study evaluates 402 bp of the mtDNA control region (CR) from 1394 cats, including cats from 25 distinct worldwide populations and 26 breeds. Eighty-three percent of the cats are represented by 12 major mitotypes. An additional 8.0% are clearly derived from the major mitotypes. Unique sequences are found in 7.5% of the cats. The overall genetic diversity for this data set is 0.8813±0.0046 with a random match probability of 11.8%. This region of the cat mtDNA has discriminatory power suitable for forensic application worldwide.

  16. A novel class of small repetitive DNA sequences in Enterococcus faecalis.

    Science.gov (United States)

    Venditti, Rossella; De Gregorio, Eliana; Silvestro, Giustina; Bertocco, Tullia; Salza, Maria Francesca; Zarrilli, Raffaele; Di Nocera, Pier Paolo

    2007-06-01

    The structural organization of Enterococcus faecalis repeats (EFAR) is described, palindromic DNA sequences identified in the genome of the Enterococcus faecalis V583 strain by in silico analyses. EFAR are a novel type of miniature insertion sequences, which vary in size from 42 to 650 bp. Length heterogeneity results from the variable assembly of 16 different sequence types. Most elements measure 170 bp, and can fold into peculiar L-shaped structures resulting from the folding of two independent stem-loop structures (SLSs). Homologous chromosomal regions lacking or containing EFAR sequences were identified by PCR among 20 E. faecalis clinical isolates of different genotypes. Sequencing of a representative set of 'empty' sites revealed that 24-37 bp-long sequences, unrelated to each other but all able to fold into SLSs, functioned as targets for the integration of EFAR. In the process, most of the SLS had been deleted, but part of the targeted stems had been retained at EFAR termini.

  17. Karyotypic Evolution and Chromosomal Organization of Repetitive DNA Sequences in Species of Panaque, Panaqolus, and Scobinancistrus (Siluriformes and Loricariidae) from the Amazon Basin.

    Science.gov (United States)

    Ayres-Alves, Thayana; Cardoso, Adauto Lima; Nagamachi, Cleusa Yoshiko; Sousa, Leandro Melo de; Pieczarka, Julio Cesar; Noronha, Renata Coelho Rodrigues

    2017-06-01

    Loricariidae family comprises the greatest variability of Neotropical catfish species, with more than 800 valid species. This family shows significant chromosomal diversity. Mapping of repetitive DNA sequences can be very useful in exploring such diversity, especially among groups that appear to share a preserved karyotypic macrostructure. We describe the karyotypes of Panaque armbrusteri and Panaqolus sp., as assessed using classical cytogenetic methods. Moreover, we offer a map of their repetitive sequences, including 18S and 5S ribosomal DNAs, the Rex1 and Rex3 retrotransposons, and the Tc1-mariner transposon in P. armbrusteri, Panaqolus sp., Scobinancistrus aureatus, and Scobinancistrus pariolispos. Those species share chromosome numbers of 2n = 52, but are divergent in their chromosome structures and the distributions of their repetitive DNA sequences. In situ hybridization with 18S and 5S rDNA probes confirms chromosome location in different pairs; in Panaqolus sp. these sites are in synteny. This multigene family organization can be explained by the occurrence of chromosome rearrangements, and possible events, such as transposition and unequal crossing-over. Rex1 and Rex3 retrotransposons and the Tc1-mariner transposon appeared predominantly dispersed and in small clusters in some chromosome regions. These data emphasize the importance of repetitive sequences in promoting the karyotypic evolution of these species.

  18. Cytogenetic variation of repetitive DNA elements in Hoplias malabaricus (Characiformes - Erythrinidae) from white, black and clear water rivers of the Amazon basin.

    Science.gov (United States)

    Santos, Fabíola Araújo Dos; Marques, Diego Ferreira; Terencio, Maria Leandra; Feldberg, Eliana; Rodrigues, Luís Reginaldo R

    2016-03-01

    Hoplias malabaricus is a common fish species occurring in white, black and clear water rivers of the Amazon basin. Its large distribution across distinct aquatic environments can pose stressful conditions for dispersal and creates possibilities for the emergence of local adaptive profiles. We investigated the chromosomal localization of repetitive DNA markers (constitutive heterochromatin, rDNA and the transposable element REX-3) in populations from the Amazonas river (white water), the Negro river (black water) and the Tapajós river (clear water), in order to address the variation/association of cytogenomic features and environmental conditions. We found a conserved karyotypic macrostructure with a diploid number of 40 chromosomes (20 metacentrics + 20 submetacentrics) in all the samples. Heteromorphism in pair 14 was detected as evidence for the initial differentiation of an XX/XY system. Minor differences detected in the amount of repetitive DNA markers are interpreted as possible signatures of local adaptations to distinct aquatic environments.

  19. Genomic organization and dynamics of repetitive DNA sequences in representatives of three Fagaceae genera.

    Science.gov (United States)

    Alves, Sofia; Ribeiro, Teresa; Inácio, Vera; Rocheta, Margarida; Morais-Cecílio, Leonor

    2012-05-01

    Oaks, chestnuts, and beeches are economically important species of the Fagaceae. To understand the relationship between these members of this family, a deep knowledge of their genome composition and organization is needed. In this work, we have isolated and characterized several AFLP fragments obtained from Quercus rotundifolia Lam. through homology searches in available databases. Genomic polymorphisms involving some of these sequences were evaluated in two species of Quercus, one of Castanea, and one of Fagus with specific primers. Comparative FISH analysis with generated sequences was performed in interphase nuclei of the four species, and the co-immunolocalization of 5-methylcytosine was also studied. Some of the sequences isolated proved to be genus-specific, while others were present in all the genera. Retroelements, either gypsy-like of the Tat/Athila clade or copia-like, are well represented, and most are dispersed in euchromatic regions of these species with no DNA methylation associated, pointing to an interspersed arrangement of these retroelements with potential gene-rich regions. A particular gypsy-sequence is dispersed in oaks and chestnut nuclei, but its confinement to chromocenters in beech evidences genome restructuring events during evolution of Fagaceae. Several sequences generated in this study proved to be good tools to comparatively study Fagaceae genome organization.

  20. Effectiveness of enterobacterial repetitive intergenic consensus PCR and random amplified polymorphic DNA fingerprinting for Helicobacter pylori strain differentiation.

    Science.gov (United States)

    Finger, S Alison; Velapatiño, Billie; Kosek, Margaret; Santivañez, Livia; Dailidiene, Daiva; Quino, Willi; Balqui, Jacqueline; Herrera, Phabiola; Berg, Douglas E; Gilman, Robert H

    2006-07-01

    We compared the robustness and discriminatory power of the enterobacterial repetitive intergenic consensus (ERIC) and random amplified polymorphic DNA (RAPD) fingerprinting methods for detecting cases of mixed Helicobacter pylori infection in Peruvian shantytown residents. H. pylori isolates from 63 participants were cultured, and five single colonies and a pool of additional colonies from each participant were analyzed by ERIC-PCR and by RAPD tests with four 10-nucleotide primers (one primer per reaction). There was 94% agreement between the ERIC and RAPD profiles in classifying sets of isolates as uniform versus closely related but not identical versus probably unrelated, indicating a high kappa statistic of 0.8942. Subtle differences in related ERIC or RAPD patterns likely reflect gene transfer between strains, recombination, and/or mutation, whereas markedly different patterns reflect infection by unrelated strains. At least half of infected shantytown residents seemed to carry more than one H. pylori strain, although in 19 of 31 persons, the strains were closely related. Three RAPD tests, each with a different primer, were needed to achieve the sensitivity of one ERIC test. ERIC-PCR constitutes a resource- and time-efficient method for H. pylori strain differentiation.

  1. Random DNA libraries from three species of the stick insect genus Bacillus (Insecta: Phasmida): repetitive DNA characterization and first observation of polyneopteran MITEs.

    Science.gov (United States)

    Ricci, Marco; Luchetti, Andrea; Bonandin, Livia; Mantovani, Barbara

    2013-12-01

    The repetitive DNA content of the stick insect species Bacillus rossius (facultative parthenogenetic), Bacillus grandii (gonochoric), and Bacillus atticus (obligate parthenogenetic) was analyzed through the survey of random genomic libraries roughly corresponding to 0.006% of the genome. By repeat masking, 19 families of transposable elements were identified (two LTR and six non-LTR retrotransposons; 11 DNA transposons). Moreover, a de novo analysis revealed, among the three libraries, the first MITE family observed in polyneopteran genomes. On the whole, transposable element abundance represented 23.3% of the genome in B. rossius, 22.9% in B. atticus, and 18% in B. grandii. Tandem repeat content in the three libraries is much lower: 1.32%, 0.64%, and 1.86% in B. rossius, B. grandii, and B. atticus, respectively. Microsatellites are the most abundant in all species. Minisatellites were only found in B. rossius and B. atticus, and five monomers belonging to the Bag320 satellite family were detected in B. atticus. Assuming the survey provides adequate representation of the relative genome, the obligate parthenogenetic species (B. atticus), compared with the other two species analyzed, does not show a lower transposable element content, as expected from some theoretical and empirical studies.

  2. Patterns of rDNA and telomeric sequences diversification: contribution to repetitive DNA organization in Phyllostomidae bats.

    Science.gov (United States)

    Calixto, Merilane da Silva; de Andrade, Izaquiel Santos; Cabral-de-Mello, Diogo Cavalcanti; Santos, Neide; Martins, Cesar; Loreto, Vilma; de Souza, Maria José

    2014-02-01

    Chromosomal organization and the evolution of genome architecture can be investigated by physical mapping of the genes for 45S and 5S ribosomal DNAs (rDNAs) and by the analysis of telomeric sequences. We studied 12 species of bats belonging to four subfamilies of the family Phyllostomidae in order to correlate patterns of distribution of heterochromatin and the multigene families for rDNA. The number of clusters for 45S gene ranged from one to three pairs, with exclusively location in autosomes, except for Carollia perspicillata that had in X chromosome. The 5S gene all the species studied had only one site located on an autosomal pair. In no species the 45S and 5S genes collocated. The fluorescence in situ hybridization (FISH) probe for telomeric sequences revealed fluorescence on all telomeres in all species, except in Carollia perspicillata. Non-telomeric sites in the pericentromeric region of the chromosomes were observed in most species, ranged from one to 12 pairs. Most interstitial telomeric sequences were coincident with heterochromatic regions. The results obtained in the present work indicate that different evolutionary mechanisms are acting in Phyllostomidae genome architecture, as well as the occurrence of Robertsonian fusion during the chromosomal evolution of bats without a loss of telomeric sequences. These data contribute to understanding the organization of multigene families and telomeric sequences on bat genome as well as the chromosomal evolutionary history of Phyllostomidae bats.

  3. Roles of repetitive sequences

    Energy Technology Data Exchange (ETDEWEB)

    Bell, G.I.

    1991-12-31

    The DNA of higher eukaryotes contains many repetitive sequences. The study of repetitive sequences is important, not only because many have important biological function, but also because they provide information on genome organization, evolution and dynamics. In this paper, I will first discuss some generic effects that repetitive sequences will have upon genome dynamics and evolution. In particular, it will be shown that repetitive sequences foster recombination among, and turnover of, the elements of a genome. I will then consider some examples of repetitive sequences, notably minisatellite sequences and telomere sequences as examples of tandem repeats, without and with respectively known function, and Alu sequences as an example of interspersed repeats. Some other examples will also be considered in less detail.

  4. Roles of repetitive sequences

    Energy Technology Data Exchange (ETDEWEB)

    Bell, G.I.

    1991-12-31

    The DNA of higher eukaryotes contains many repetitive sequences. The study of repetitive sequences is important, not only because many have important biological function, but also because they provide information on genome organization, evolution and dynamics. In this paper, I will first discuss some generic effects that repetitive sequences will have upon genome dynamics and evolution. In particular, it will be shown that repetitive sequences foster recombination among, and turnover of, the elements of a genome. I will then consider some examples of repetitive sequences, notably minisatellite sequences and telomere sequences as examples of tandem repeats, without and with respectively known function, and Alu sequences as an example of interspersed repeats. Some other examples will also be considered in less detail.

  5. An ancient satellite DNA has maintained repetitive units of the original structure in most species of the living fossil plant genus Zamia.

    Science.gov (United States)

    Cafasso, Donata; Chinali, Gianni

    2014-03-01

    ZpS1 satellite DNA is specific to the genus Zamia and presents repetitive units organized as long arrays and also as very short arrays dispersed in the genome. We have characterized the structure of the ZpS1 repeats in 12 species representative of the whole geographic distribution of the genus. In most species, the clone most common sequences (cMCS) were so similar that a general most common sequence (GMCS) of the ZpS1 repetitive unit in the genus could be obtained. The few partial variations from the GMCS found in cMCS of some species correspond to variable positions present in most other species, as indicated by the clone consensus sequences (cCS). Two species have an additional species-specific variety of ZpS1 satellite. The dispersed repeats were found to contain more mutations than repeats from long arrays. Our results indicate that all or most species of Zamia inherited the ZpS1 satellite from a common ancestor in Miocene and have maintained repetitive units of the original structure till present. The features of ZpS1 satellite in the genus Zamia are poorly compatible with the model of concerted evolution, but they are perfectly consistent with a new model of satellite evolution based on experimental evidences indicating that a specific amplification-substitution repair mechanism maintains the homogeneity and stability of the repeats structure in each satellite DNA originally present in a species as long as the species exists.

  6. Cloning of DNA sequences localized on proximal fluorescent chromosome bands by microdissection in Pinus densiflora Sieb. & Zucc.

    Science.gov (United States)

    Hizume, M; Shibata, F; Maruyama, Y; Kondo, T

    2001-09-01

    Japanese red pine, Pinus densiflora, has 2n=24 chromosomes, of which most carry chromomycin A3 (CMA) and 4',6-diamidino-2-phenylindole (DAPI) bands at their centromere-proximal regions. It was proposed that these regions contain highly repetitive DNA. The DNA localized in the proximal fluorescent bands was isolated and characterized. In P. densiflora, centromeric and neighboring segments of the somatic chromosomes were dissected with a manual micromanipulator. The centromeric DNA was amplified from the DNA contained in dissected centromeric segments by degenerate oligonucleotide primed-polymerase chain reaction (DOP-PCR) and a cloned DNA library was constructed. Thirty-one clones carrying highly repetitive DNA were selected by colony hybridization using Cot-1 DNA from this species as a probe, and their chromosomal localization was determined by fluorescent in situ hybridization (FISH). Clone PDCD501 was localized to the proximal CMA band of 20 chromosomes. This clone contained tandem repeats, comprising a 27 bp repeat unit, which was sufficient to provide the proximal FISH signal, with a 52.3% GC content. The repetitive sequence was named PCSR (proximal CMA band-specific repeat). Clone PDCD159 was 1700 bp in length, with a 61.7% AT content, and produced FISH signals at the proximal DAPI band of the remaining four chromosomes. Four clones hybridized strongly to the secondary constriction and gave weak signals at the centromeric region of several chromosomes. Clone PDCD537, one of the four clones, was homologous to the 26S rRNA gene. A PCR experiment using microdissected centromeric regions suggested that the centromeric region contains 18S and 26S rDNA. Another 24 clones hybridized to whole chromosome arms, with varying intensities and might represent dispersed repetitive DNA.

  7. Repetitive, Marker-Free, Site-Specific Integration as a Novel Tool for Multiple Chromosomal Integration of DNA

    DEFF Research Database (Denmark)

    Petersen, Kia Vest; Martinussen, Jan; Jensen, Peter Ruhdal

    2013-01-01

    We present a tool for repetitive, marker-free, site-specific integration in Lactococcus lactis, in which a nonreplicating plasmid vector (pKV6) carrying a phage attachment site (attP) can be integrated into a bacterial attachment site (attB). The novelty of the tool described here is the inclusio...

  8. Chromosomal Mapping of Repetitive DNA Sequences in Five Species of Astyanax (Characiformes, Characidae) Reveals Independent Location of U1 and U2 snRNA Sites and Association of U1 snRNA and 5S rDNA.

    Science.gov (United States)

    Silva, Duilio M Z A; Utsunomia, Ricardo; Pansonato-Alves, José C; Oliveira, Cláudio; Foresti, Fausto

    2015-01-01

    Astyanax is a genus of Characidae fishes currently composed of 155 valid species. Previous cytogenetic studies revealed high chromosomal diversification among them, and several studies have been performed using traditional cytogenetic techniques to investigate karyotypes and chromosomal locations of 18S and 5S rDNA genes. However, only a few studies are currently available about other repetitive sequences. Here, the chromosomal location of small nuclear RNA genes, identified as U1 and U2 snRNA clusters, was established and compared to the distribution of 5S rDNA and histone clusters in 5 Astyanax species (A. paranae, A. fasciatus, A. bockmanni, A. altiparanae, and A. jordani) using FISH. The cytogenetic mapping of U1 and U2 snRNA demonstrated a conserved pattern in the number of sites per genome independent of the location in Astyanax species. The location of the U1 snRNA gene was frequently associated with 5S rDNA sequences, indicating a possible interaction between the distinct repetitive DNA families. Finally, comparisons involving the location of U1 and U2 snRNA clusters in the chromosomes of Astyanax species revealed a very diverse pattern, suggesting that many rearrangements have occurred during the diversification process of this group. © 2015 S. Karger AG, Basel.

  9. Highly species-specific centromeric repetitive DNA sequences in lizards: molecular cytogenetic characterization of a novel family of satellite DNA sequences isolated from the water monitor lizard (Varanus salvator macromaculatus, Platynota).

    Science.gov (United States)

    Chaiprasertsri, Nampech; Uno, Yoshinobu; Peyachoknagul, Surin; Prakhongcheep, Ornjira; Baicharoen, Sudarath; Charernsuk, Saranon; Nishida, Chizuko; Matsuda, Yoichi; Koga, Akihiko; Srikulnath, Kornsorn

    2013-01-01

    Two novel repetitive DNA sequences, VSAREP1 and VSAREP2, were isolated from the water monitor lizard (Varanus salvator macromaculatus, Platynota) and characterized using molecular cytogenetics. The respective lengths and guanine-cytosine (GC) contents of the sequences were 190 bp and 57.5% for VSAREP1 and 185 bp and 59.7% for VSAREP2, and both elements were tandemly arrayed as satellite DNA in the genome. VSAREP1 and VSAREP2 were each located at the C-positive heterochromatin in the pericentromeric region of chromosome 2q, the centromeric region of chromosome 5, and 3 pairs of microchromosomes. This suggests that genomic compartmentalization between macro- and microchromosomes might not have occurred in the centromeric repetitive sequences of V. salvator macromaculatus. These 2 sequences did only hybridize to genomic DNA of V. salvator macromaculatus, but no signal was observed even for other squamate reptiles, including Varanus exanthematicus, which is a closely related species of V. salvator macromaculatus. These results suggest that these sequences were differentiated rapidly or were specifically amplified in the V. salvator macromaculatus genome.

  10. Epigenetic analyses and the distribution of repetitive DNA and resistance genes reveal the complexity of common bean (Phaseolus vulgaris L., Fabaceae) heterochromatin.

    Science.gov (United States)

    Fonsêca, Artur; Richard, Manon M S; Geffroy, Valérie; Pedrosa-Harand, Andrea

    2014-01-01

    The common bean (Phaseolus vulgaris L.) is the main representative of its genus and one of most important sources of proteins in African and Latin American countries. Although it is a species with a small genome, its pericentromeric and subtelomeric heterochromatin fractions are interspersed with single-copy sequences and active genes, suggesting a less compartmentalized genome organization. The present study characterized its chromatin fractions, associating the distribution of repetitive sequences and resistance genes with histone and DNA epigenetic modifications with and without biotic stress. Immunostaining with H3K4me3 and H4K5ac were generally associated with euchromatic regions, whereas H3K9me2, H3K27me1, and 5mC preferentially labeled the pericentromeric heterochromatin. The 45S rDNA and centromeric DNA sequences were hypomethylated as were most of the terminal heterochromatic blocks. The largest of them, which is associated with resistance genes, was also hypomethylated after the plants were infected with virulent and avirulent strains of the fungus Colletotrichum lindemuthianum, suggesting no correlation with control of resistance gene expression. The results highlighted the differences between subtelomeric and pericentromeric heterochromatin as well as variation within the pericentromeric heterochromatin. © 2014 S. Karger AG, Basel.

  11. Kaposi's Sarcoma-Associated Herpesvirus Rta Tetramers Make High-Affinity Interactions with Repetitive DNA Elements in the Mta Promoter To Stimulate DNA Binding of RBP-Jk/CSL ▿ †

    Science.gov (United States)

    Palmeri, Diana; Carroll, Kyla Driscoll; Gonzalez-Lopez, Olga; Lukac, David M.

    2011-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV; also known as human herpesvirus 8 [HHV-8]) is the etiologic agent of Kaposi's sarcoma (KS) and lymphoproliferative diseases. We previously demonstrated that the KSHV lytic switch protein Rta stimulates DNA binding of the cellular RBP-Jk/CSL protein, the nuclear component of the Notch pathway, on Rta target promoters. In the current study, we define the promoter requirements for formation of transcriptionally productive Rta/RBP-Jk/DNA complexes. We show that highly pure Rta footprints 7 copies of a previously undescribed repetitive element in the promoter of the essential KSHV Mta gene. We have termed this element the “CANT repeat.” CANT repeats are found on both strands of DNA and have a consensus sequence of ANTGTAACANT(A/T)(A/T)T. We demonstrate that Rta tetramers make high-affinity interactions (i.e., nM) with 64 bp of the Mta promoter but not single CANT units. The number of CANT repeats, their presence in palindromes, and their positions relative to the RBP-Jk binding site determine the optimal target for Rta stimulation of RBP-Jk DNA binding and formation of ternary Rta/RBP-Jk/DNA complexes. DNA binding and tetramerization mutants of Rta fail to stimulate RBP-Jk DNA binding. Our chromatin immunoprecipitation assays show that RBP-Jk DNA binding is broadly, but selectively, stimulated across the entire KSHV genome during reactivation. We propose a model in which tetramerization of Rta allows it to straddle RBP-Jk and contact repeat units on both sides of RBP-Jk. Our study integrates high-affinity Rta DNA binding with the requirement for a cellular transcription factor in Rta transactivation. PMID:21880753

  12. GENETIC DIVERSITY OF TYPHA LATIFOLIA (TYPHACEAE) AND THE IMPACT OF POLLUTANTS EXAMINED WITH TANDEM-REPETITIVE DNA PROBES

    Science.gov (United States)

    Genetic diversity at variable-number-tandem-repeat (VNTR) loci was examined in the common cattail, Typha latifolia (Typhaceae), using three synthetic DNA probes composed of tandemly repeated "core" sequences (GACA, GATA, and GCAC). The principal objectives of this investigation w...

  13. Association of hypomethylation of LINE-1 repetitive element in blood leukocyte DNA with an increased risk of hepatocellular carcinoma

    Institute of Scientific and Technical Information of China (English)

    Jian-zhong DI; Xiao-dong HAN; Wen-ye GU; Yu WANG; Qi ZHENG; Pin ZHANG; Hui-min WU; Zhong-zheng ZHU

    2011-01-01

    Global DNA hypomethylation has been associated with increased risk for cancers of the colorectum,bladder,breast,head and neck,and testicular germ cells.The aim of this study was to examine whether global hypomethylation in blood leukocyte DNA is associated with the risk of hepatocellular carcinoma (HCC).A total of 315HCC cases and 356 age-,sex- and HBsAg status-matched controls were included.Global methylation in blood leukocyte DNA was estimated by analyzing long interspersed element-1 (LINE-1) repeats using bisulfite-polymerase chain reaction (PCR) and pyrosequencing.We observed that the median methylation level in HCC cases (percentage of 5-methylcytosine (5mC)=77.7%) was significantly lower than that in controls (79.5% 5mC) (P=0.004,Wilcoxon rank-sum test).The odds ratios (ORs) of HCC for individuals in the third,second,and first (lowest) quartiles of LINE-1methylation were 1.1 (95% confidence interval (CI) 0.7-1.8),1.4 (95% CI 0.8-2.2),and 2.6 (95% CI 1.7-4.1) (P for trend <0.001),respectively,compared to individuals in the fourth (highest) quartile.A 1.9-fold (95% CI 1.4-2.6) increased risk of HCC was observed among individuals with LINE-1 methylation below the median compared to individuals with higher (>median) LINE-1 methylation.Our results demonstrate for the first time that individuals with global hypomethylation measured in LINE-1 repeats in blood leukocyte DNA have an increased risk for HCC.Our data provide the evidence that global hypomethylation detected in the easily obtainable DNA source of blood leukocytes may help identify individuals at risk of HCC.

  14. Repetitive transpositions of mitochondrial DNA sequences to the nucleus during the radiation of horseshoe bats (Rhinolophus, Chiroptera).

    Science.gov (United States)

    Shi, Huizhen; Dong, Ji; Irwin, David M; Zhang, Shuyi; Mao, Xiuguang

    2016-05-01

    Transposition of mitochondrial DNA into the nucleus, which gives rise to nuclear mitochondrial DNAs (NUMTs), has been well documented in eukaryotes. However, very few studies have assessed the frequency of these transpositions during the evolutionary history of a specific taxonomic group. Here we used the horseshoe bats (Rhinolophus) as a case study to determine the frequency and relative timing of nuclear transfers of mitochondrial control region sequences. For this, phylogenetic and coalescent analyzes were performed on NUMTs and authentic mtDNA sequences generated from eight horseshoe bat species. Our results suggest at least three independent transpositions, including two ancient and one more recent, during the evolutionary history of Rhinolophus. The two ancient transpositions are represented by the NUMT-1 and -2 clades, with each clade consisting of NUMTs from almost all studied species but originating from different portions of the mtDNA genome. Furthermore, estimates of the most recent common ancestor for each clade corresponded to the time of the initial diversification of this genus. The recent transposition is represented by NUMT-3, which was discovered only in a specific subgroup of Rhinolophus and exhibited a close relationship to its mitochondrial counterpart. Our similarity searches of mtDNA in the R. ferrumequinum genome confirmed the presence of NUMT-1 and NUMT-2 clade sequences and, for the first time, assessed the extent of NUMTs in a bat genome. To our knowledge, this is the first study to report on the frequency of transpositions of mtDNA occurring before the common ancestry of a genus.

  15. Novel porcine repetitive elements

    Directory of Open Access Journals (Sweden)

    Nonneman Dan J

    2006-12-01

    Full Text Available Abstract Background Repetitive elements comprise ~45% of mammalian genomes and are increasingly known to impact genomic function by contributing to the genomic architecture, by direct regulation of gene expression and by affecting genomic size, diversity and evolution. The ubiquity and increasingly understood importance of repetitive elements contribute to the need to identify and annotate them. We set out to identify previously uncharacterized repetitive DNA in the porcine genome. Once found, we characterized the prevalence of these repeats in other mammals. Results We discovered 27 repetitive elements in 220 BACs covering 1% of the porcine genome (Comparative Vertebrate Sequencing Initiative; CVSI. These repeats varied in length from 55 to 1059 nucleotides. To estimate copy numbers, we went to an independent source of data, the BAC-end sequences (Wellcome Trust Sanger Institute, covering approximately 15% of the porcine genome. Copy numbers in BAC-ends were less than one hundred for 6 repeat elements, between 100 and 1000 for 16 and between 1,000 and 10,000 for 5. Several of the repeat elements were found in the bovine genome and we have identified two with orthologous sites, indicating that these elements were present in their common ancestor. None of the repeat elements were found in primate, rodent or dog genomes. We were unable to identify any of the replication machinery common to active transposable elements in these newly identified repeats. Conclusion The presence of both orthologous and non-orthologous sites indicates that some sites existed prior to speciation and some were generated later. The identification of low to moderate copy number repetitive DNA that is specific to artiodactyls will be critical in the assembly of livestock genomes and studies of comparative genomics.

  16. Repetitive DNA in the pea (Pisum sativum L. genome: comprehensive characterization using 454 sequencing and comparison to soybean and Medicago truncatula

    Directory of Open Access Journals (Sweden)

    Navrátilová Alice

    2007-11-01

    Full Text Available Abstract Background Extraordinary size variation of higher plant nuclear genomes is in large part caused by differences in accumulation of repetitive DNA. This makes repetitive DNA of great interest for studying the molecular mechanisms shaping architecture and function of complex plant genomes. However, due to methodological constraints of conventional cloning and sequencing, a global description of repeat composition is available for only a very limited number of higher plants. In order to provide further data required for investigating evolutionary patterns of repeated DNA within and between species, we used a novel approach based on massive parallel sequencing which allowed a comprehensive repeat characterization in our model species, garden pea (Pisum sativum. Results Analysis of 33.3 Mb sequence data resulted in quantification and partial sequence reconstruction of major repeat families occurring in the pea genome with at least thousands of copies. Our results showed that the pea genome is dominated by LTR-retrotransposons, estimated at 140,000 copies/1C. Ty3/gypsy elements are less diverse and accumulated to higher copy numbers than Ty1/copia. This is in part due to a large population of Ogre-like retrotransposons which alone make up over 20% of the genome. In addition to numerous types of mobile elements, we have discovered a set of novel satellite repeats and two additional variants of telomeric sequences. Comparative genome analysis revealed that there are only a few repeat sequences conserved between pea and soybean genomes. On the other hand, all major families of pea mobile elements are well represented in M. truncatula. Conclusion We have demonstrated that even in a species with a relatively large genome like pea, where a single 454-sequencing run provided only 0.77% coverage, the generated sequences were sufficient to reconstruct and analyze major repeat families corresponding to a total of 35–48% of the genome. These data

  17. Chromosomal mapping of repetitive DNAs in the beetle Dichotomius geminatus provides the first evidence for an association of 5S rRNA and histone H3 genes in insects, and repetitive DNA similarity between the B chromosome and A complement.

    Science.gov (United States)

    Cabral-de-Mello, D C; Moura, R C; Martins, C

    2010-04-01

    Chromosomal banding techniques and repetitive DNA mapping are useful tools in comparative analysis and in the elucidation of genome organization of several groups of eukaryotes. In this study, we contributed to the knowledge of Coleoptera genomes by reporting the chromosomal organization of repetitive DNA sequences, as well as the presence and characteristics of a B chromosome in two natural populations of Dichotomius geminatus (Coleoptera; Scarabaeidae) using classical, chromosomal banding and molecular cytogenetic techniques. As in other coleopteran species, the heterochromatin was mainly concentrated in pericentromeric regions and the B chromosome was composed almost entirely of heterochromatin. Physical mapping using double fluorescent in situ hybridization was performed for the first time in Coleoptera; using DNA probes for 5S and 18S ribosomal RNA (rRNA) and histone H3 genes, we showed that ribosomal 18S rDNAs are located in chromosomes 3 and 4, whereas 5S rRNA and histone H3 genes are colocalized in chromosomal pair 2 and show an apparently interspersed organization. Moreover, these genes are not present in the B chromosome, suggesting that the B chromosome did not originate from chromosomal pairs 2, 3 or 4. On the other hand, mapping of the C(0)t-1 DNA fraction showed that the B chromosome is enriched in repetitive DNA elements, also present in the standard complement, indicating an intraspecific origin of this element in D. geminatus. These results will contribute to our understanding of genome organization and evolution of repetitive elements in Coleoptera and other insects regarding both A and B chromosomes.

  18. Differential chromosomal organization between Saguinus midas and Saguinus bicolor with accumulation of differences the repetitive sequence DNA.

    Science.gov (United States)

    Serfaty, Dayane Martins Barbosa; Carvalho, Natália Dayane Moura; Gross, Maria Claudia; Gordo, Marcelo; Schneider, Carlos Henrique

    2017-06-20

    Saguinus is the largest and most complex genus of the subfamily Callitrichinae, with 23 species distributed from the south of Central America to the north of South America with Saguinus midas having the largest geographical distribution while Saguinus bicolor has a very restricted one, affected by the population expansion in the state of Amazonas. Considering the phylogenetic proximity of the two species along with evidence on the existence of hybrids between them, as well as cytogenetic studies on Saguinus describing a conserved karyotypic macrostructure, we carried out a physical mapping of DNA repeated sequences in the mitotic chromosome of both species, since these sequences are less susceptible to evolutionary pressure and possibly perform an important function in speciation. Both species presented 2n = 46 chromosomes; in S. midas, chromosome Y is the smallest. Multiple ribosomal sites occur in both species, but chromosome pairs three and four may be regarded as markers that differ the species when subjected to G banding and distribution of retroelement LINE 1, suggesting that it may be cytogenetic marker in which it can contribute to identification of first generation hybrids in contact zone. Saguinus bicolor also presented differences in the LINE 1 distribution pattern for sexual chromosome X in individuals from different urban fragments, probably due to geographical isolation. In this context, cytogenetic analyses reveal a differential genomic organization pattern between species S. midas and S. bicolor, in addition to indicating that individuals from different urban fragments have been accumulating differences because of the isolation between them.

  19. Indole acetic acid production by fluorescent Pseudomonas spp. from the rhizosphere of Plectranthus amboinicus (Lour.) Spreng. and their variation in extragenic repetitive DNA sequences.

    Science.gov (United States)

    Sethia, Bedhya; Mustafa, Mariam; Manohar, Sneha; Patil, Savita V; Jayamohan, Nellickal Subramanian; Kumudini, Belur Satyan

    2015-06-01

    Fluorescent Pseudomonas (FP) is a heterogenous group of growth promoting rhizobacteria that regulate plant growth by releasing secondary metabolic compounds viz., indole acetic acid (IAA), siderophores, ammonia and hydrogen cyanide. In the present study, IAA producing FPs from the rhizosphere of Plectranthus amboinicus were characterized morphologically, biochemically and at the molecular level. Molecular identification of the isolates were carried out using Pseudomonas specific primers. The effect of varying time (24, 48, 72 and 96 h), Trp concentrations (100, 200, 300, 400 and 500 μg x ml(-1)), temperature (10, 26, 37 and 50 ± 2 degrees C) and pH (6, 7 and 8) on IAA production by 10 best isolates were studied. Results showed higher IAA production at 72 h incubation, at 300 μg x ml(-1) Trp concentration, temperature 26 ± 2 degrees C and pH 7. TLC with acidified ethyl acetate extract showed that the IAA produced has a similar Rf value to that of the standard IAA. Results of TLC were confirmed by HPLC analysis. Genetic diversity of the isolates was also studied using 40 RAPD and 4 Rep primers. Genetic diversity parameters such as dominance, Shannon index and Simpson index were calculated. Out of 40 RAPD primers tested, 9 (2 OP-D series and 7 OP-E series) were shortlisted for further analysis. Studies using RAPD, ERIC, BOX, REP and GTG5 primers revealed that isolates exhibit significant diversity in repetitive DNA sequences irrespective of the rhizosphere.

  20. Chromosomal mapping of repetitive DNAs in Gobionellus oceanicus and G. stomatus (Gobiidae; Perciformes): A shared XX/XY system and an unusual distribution of 5S rDNA sites on the Y chromosome.

    Science.gov (United States)

    Lima-Filho, Paulo A; Amorim, Karlla D J; Cioffi, Marcelo B; Bertollo, Luiz A C; Molina, Wagner F

    2014-01-01

    With nearly 2,000 species, Gobiidae is the most specious family of the vertebrates. This high level of speciation is accompanied by conspicuous karyotypic modifications, where the role of repetitive sequences remains largely unknown. This study analyzed the karyotype of 2 species of the genus Gobionellus and mapped 18S and 5S ribosomal RNA genes and (CA)15 microsatellite sequences onto their chromosomes. G. oceanicus (2n = 56; ♂ 12 metacentrics (m) + 4 submetacentrics (sm) + 1 subtelocentric (st) + 39 acrocentrics (a); ♀ 12m + 4sm + 2st + 38a) and G. stomatus (2n = 56; ♂ 20m + 14sm + 1st + 21a; ♀ 20m + 14sm + 2st + 20a) possess the highest diploid chromosome number among the Gobiidae and have different karyotypes. Both species share an XX/XY sex chromosome system with a large subtelocentric X and a small acrocentric Y chromosome which is rich in (CA)15 sequences and bears 5S rRNA sites. Although coding and noncoding repetitive DNA sequences may be involved in the genesis or differentiation of the sex chromosomes, the exclusive presence of 5S rDNA sites on the Y, but not on the X chromosome of both species, represents a novelty in fishes. In summary, the karyotypic differences, as well as new data on the sex chromosome systems in these 2 Gobiidae species, confirm the high chromosomal dynamism observed in this family.

  1. Repetitive maladaptive behavior: beyond repetition compulsion.

    Science.gov (United States)

    Bowins, Brad

    2010-09-01

    Maladaptive behavior that repeats, typically known as repetition compulsion, is one of the primary reasons that people seek psychotherapy. However, even with psychotherapeutic advances it continues to be extremely difficult to treat. Despite wishes and efforts to the contrary repetition compulsion does not actually achieve mastery, as evidenced by the problem rarely resolving without therapeutic intervention, and the difficulty involved in producing treatment gains. A new framework is proposed, whereby such behavior is divided into behavior of non-traumatic origin and traumatic origin with some overlap occurring. Repetitive maladaptive behavior of non-traumatic origin arises from an evolutionary-based process whereby patterns of behavior frequently displayed by caregivers and compatible with a child's temperament are acquired and repeated. It has a familiarity and ego-syntonic aspect that strongly motivates the person to retain the behavior. Repetitive maladaptive behavior of traumatic origin is characterized by defensive dissociation of the cognitive and emotional components of trauma, making it very difficult for the person to integrate the experience. The strong resistance of repetitive maladaptive behavior to change is based on the influence of both types on personality, and also factors specific to each. Psychotherapy, although very challenging at the best of times, can achieve the mastery wished and strived for, with the aid of several suggestions provided.

  2. Variation in extragenic repetitive DNA sequences in Pseudomonas syringae and potential use of modified REP primers in the identification of closely related isolates

    Directory of Open Access Journals (Sweden)

    Elif Çepni

    2012-01-01

    Full Text Available In this study, Pseudomonas syringe pathovars isolated from olive, tomato and bean were identified by species-specific PCR and their genetic diversity was assessed by repetitive extragenic palindromic (REP-PCR. Reverse universal primers for REP-PCR were designed by using the bases of A, T, G or C at the positions of 1, 4 and 11 to identify additional polymorphism in the banding patterns. Binding of the primers to different annealing sites in the genome revealed additional fingerprint patterns in eight isolates of P. savastanoi pv. savastanoi and two isolates of P. syringae pv. tomato. The use of four different bases in the primer sequences did not affect the PCR reproducibility and was very efficient in revealing intra-pathovar diversity, particularly in P. savastanoi pv. savastanoi. At the pathovar level, the primer BOX1AR yielded shared fragments, in addition to five bands that discriminated among the pathovars P. syringae pv. phaseolicola, P. savastanoi pv. savastanoi and P. syringae pv. tomato. REP-PCR with a modified primer containing C produced identical bands among the isolates in a pathovar but separated three pathovars more distinctly than four other primers. Although REP-and BOX-PCRs have been successfully used in the molecular identification of Pseudomonas isolates from Turkish flora, a PCR based on inter-enterobacterial repetitive intergenic concensus (ERIC sequences failed to produce clear banding patterns in this study.

  3. Grammatical Change through Repetition.

    Science.gov (United States)

    Arevart, Supot

    1989-01-01

    The effect of repetition on grammatical change in an unrehearsed talk is examined based on a case study of a single learner. It was found that repetition allows for accuracy monitoring in that errors committed in repeated contexts undergo correction. Implications for teaching are discussed. (23 references) (LB)

  4. The Negative Repetition Effect

    Science.gov (United States)

    Mulligan, Neil W.; Peterson, Daniel J.

    2013-01-01

    A fundamental property of human memory is that repetition enhances memory. Peterson and Mulligan (2012) recently documented a surprising "negative repetition effect," in which participants who studied a list of cue-target pairs twice recalled fewer targets than a group who studied the pairs only once. Words within a pair rhymed, and…

  5. Comparative analysis of A, B,C and D genomes in the genus Oryza with C0t-1 DNA of C genome

    Institute of Scientific and Technical Information of China (English)

    LAN Weizhen; QIN Rui; LI Gang; HE Guangcun

    2006-01-01

    Fluorescence in situ hybridization (FISH)was applied to somatic chromosomes preparations of Oryza officinalis Wall. (CC), O. sativa L. (AA)×O. officinalis F1 hybrid (AC), backcross progenies BC1 (AAC and ACC), O. latifolia Desv. (CCDD), O. alta Swallen (CCDD) and O. punctata Kotschy (BBCC)with a labelled probe of Cot-1 DNA from O. officinalis.In O. officinalis, the homologous chromosomes showed similar signal bands probed by C0t-1 DNA and karyotype analysis was conducted based on the band patterns. Using no blocking DNA, the probe identified the chromosomes of C genome clearly, but detected few signals on chromosomes of A genome in the F1 hybrid and two backcross progenies of BC1.It is obvious that the highly and moderately repetitive DNA sequences were considerably different between C and A genomes. The chromosomes of C genome were also discriminated from the chromosomes of D-and B-genome in the tetraploid species O. latifolia, O.alta and O. punctata by C0t-1 DNA-FISH. Comparison of the fluorescence intensity on the chromosomes of B, C and D genomes in O. latifolia, O. alta,and O. punctata indicated that the differentiations between C and D genomes are less than that between C and B genomes. The relationship between C and D genomes in O. alta is closer than that of C and D genomes in O. latifolia. This would be one of the causes for the fact that both the genomes are of the same karyotype (CCDD) but belong to different species. The above results showed that the C0t-1 DNA had a high specificity of genome and species. In this paper, the origin of allotetraploid in genus Oryza is also discussed.

  6. Repetition and Translation Shifts

    Directory of Open Access Journals (Sweden)

    Simon Zupan

    2006-06-01

    Full Text Available Repetition manifests itself in different ways and at different levels of the text. The first basic type of repetition involves complete recurrences; in which a particular textual feature repeats in its entirety. The second type involves partial recurrences; in which the second repetition of the same textual feature includes certain modifications to the first occurrence. In the article; repetitive patterns in Edgar Allan Poe’s short story “The Fall of the House of Usher” and its Slovene translation; “Konec Usherjeve hiše”; are compared. The author examines different kinds of repetitive patterns. Repetitions are compared at both the micro- and macrostructural levels. As detailed analyses have shown; considerable microstructural translation shifts occur in certain types of repetitive patterns. Since these are not only occasional; sporadic phenomena; but are of a relatively high frequency; they reduce the translated text’s potential for achieving some of the gothic effects. The macrostructural textual property particularly affected by these shifts is the narrator’s experience as described by the narrative; which suffers a reduction in intensity.

  7. Identification and molecular epidemiology of dermatophyte isolates by repetitive-sequence-PCR-based DNA fingerprinting using the DiversiLab system in Turkey.

    Science.gov (United States)

    Koc, A Nedret; Atalay, Mustafa A; Inci, Melek; Sariguzel, Fatma M; Sav, Hafize

    2017-05-01

    Dermatophyte species, isolation and identification in clinical samples are still difficult and take a long time. The identification and molecular epidemiology of dermatophytes commonly isolated in a clinical laboratory in Turkey by repetitive sequence-based PCR (rep-PCR) were assessed by comparing the results with those of reference identification. A total of 44 dermatophytes isolated from various clinical specimens of 20 patients with superficial mycoses in Kayseri and 24 patients in Hatay were studied. The identification of dermatophyte isolates was based on the reference identification and rep-PCR using the DiversiLab System (BioMerieux). The genotyping of dermatophyte isolates from different patients was determined by rep-PCR. In the identification of dermatophyte isolates, agreement between rep-PCR and conventional methods was 87.8 % ( 36 of 41). The dermatophyte strains belonged to four clones (A -D) which were determined by the use of rep-PCR. The dermatophyte strains in Clone B, D showed identical patterns with respect to the region. In conclusion, rep-PCR appears to be useful for evaluation of the identification and clonal relationships between Trichophyton rubrum species complex and Trichophyton mentagrophytes species complex isolates. The similarity and diversity of these isolates may be assessed according to different regions by rep-PCR. © 2017 Blackwell Verlag GmbH.

  8. Trialogue: Preparation, Repetition and...

    Science.gov (United States)

    Oberg, Antoinette; And Others

    1996-01-01

    This paper interrogates both curriculum theory and the limits and potentials of textual forms. A set of overlapping discourses (a trialogue) focuses on inquiring into the roles of obsession and repetition in creating deeply interpretive locations for understanding. (SM)

  9. 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.

  10. PCR amplification of repetitive sequences as a possible approach in relative species quantification

    DEFF Research Database (Denmark)

    Ballin, Nicolai Zederkopff; Vogensen, Finn Kvist; Karlsson, Anders H

    2012-01-01

    in binary mixtures. PCR LUX primers were designed that amplify repetitive and single copy sequences to establish the species dependent number (constants) (SDC) of amplified repetitive sequences per genome. The SDCs and data from amplification of repetitive sequences were tested for their applicability...... to relatively quantify the amount of chicken DNA in a binary mixture of chicken DNA and pig DNA. However, the designed PCR primers lack the specificity required for regulatory species control....

  11. Intense genomic reorganization in the genus Oecomys (Rodentia, Sigmodontinae: comparison between DNA barcoding and mapping of repetitive elements in three species of the Brazilian Amazon

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    Renan Gabriel Gomes Junior

    2016-09-01

    Full Text Available Oecomys Thomas, 1906 is one of the most diverse and widely distributed genera within the tribe Oryzomyini. At least sixteen species in this genus have been described to date, but it is believed this genus contains undescribed species. Morphological, molecular and cytogenetic study has revealed an uncertain taxonomic status for several Oecomys species, suggesting the presence of a complex of species. The present work had the goal of contributing to the genetic characterization of the genus Oecomys in the Brazilian Amazon. Thirty specimens were collected from four locations in the Brazilian Amazon and three nominal species recognized: Oecomys auyantepui (Tate, 1939, O. bicolor (Tomes, 1860 and O. rutilus (Anthony, 1921. COI sequence analysis grouped O. auyantepui, O. bicolor and O. rutilus specimens into one, three and two clades, respectively, which is consistent with their geographic distribution. Cytogenetic data for O. auyantepui revealed the sympatric occurrence of two different diploid numbers, 2n=64/NFa=110 and 2n=66/NFa=114, suggesting polymorphism while O. bicolor exhibited 2n=80/NFa=142 and O. rutilus 2n=54/NFa=90. The distribution of constitutive heterochromatin followed a species-specific pattern. Interspecific variation was evident in the chromosomal location and number of 18S rDNA loci. However, not all loci showed signs of activity. All three species displayed a similar pattern for 5S rDNA, with only one pair carrying this locus. Interstitial telomeric sites were found only in O. auyantepui. The data presented in this work reinforce intra- and interspecific variations observed in the diploid number of Oecomys species and indicate that chromosomal rearrangements have led to the appearance of different diploid numbers and karyotypic formulas.

  12. Do DNA extraction methods and Taq polimerase quality improve the double repetitive element (DRE PCR typing method for Mycobacterium tuberculosis strains? Os métodos de extração de DNA e a qualidade DA Taq polimerase podem melhorar a tipagem molecular de M. tuberculosis por DRE-PCR

    Directory of Open Access Journals (Sweden)

    Hebe Rodrigues Cavalcanti

    2007-09-01

    Full Text Available Double repetitive element (DRE PCR amplification is a simple Mycobacterium tuberculosis typing method, however amplification failure or poor resolution of bands commit its efficacy. In order to verify if whether or not these features could be minimized by improving DNA extraction procedures or Taq polymerise quality, DRE-PCR was performed on 24 M. tuberculosis DNA samples extracted by heat-shock, mechanical and enzymatic methods applying conventional and hot start Taq pol. We demonstrated that when dealing with the Mycobacterium tuberculosis DRE-PCR typing method, Taq pol of better quality might be more important to improve amplification than the DNA extraction method.Amplificação de duplo elemento repetido (DRE por PCR é um método simples para tipagem de Mycobacterium tuberculosis, entretanto falha ou a baixa resolução das bandas na amplificação compromete a eficiência do método. Com o objetivo de verificar se estes problemas podem ou não ser minimizados pela utilização de diferentes procedimentos de extração de DNA ou de qualidades de Taq polimerase, DRE-PCR foi ensaiado em 24 amostras de DNA de M. tuberculosis extraídos pelos métodos de choque-térmico, - mecânico e enzimático utilizando Taq polimerase convencional e hot start Taq pol. Foi demonstrado que a qualidade da Taq pol utilizada talvez seja mais importante para uma melhor amplificação que o método de extração de DNA empregado.

  13. Repetitive Elements in Mycoplasma hyopneumoniae Transcriptional Regulation

    Science.gov (United States)

    Cattani, Amanda Malvessi; Siqueira, Franciele Maboni; Guedes, Rafael Lucas Muniz; Schrank, Irene Silveira

    2016-01-01

    Transcriptional regulation, a multiple-step process, is still poorly understood in the important pig pathogen Mycoplasma hyopneumoniae. Basic motifs like promoters and terminators have already been described, but no other cis-regulatory elements have been found. DNA repeat sequences have been shown to be an interesting potential source of cis-regulatory elements. In this work, a genome-wide search for tandem and palindromic repetitive elements was performed in the intergenic regions of all coding sequences from M. hyopneumoniae strain 7448. Computational analysis demonstrated the presence of 144 tandem repeats and 1,171 palindromic elements. The DNA repeat sequences were distributed within the 5’ upstream regions of 86% of transcriptional units of M. hyopneumoniae strain 7448. Comparative analysis between distinct repetitive sequences found in related mycoplasma genomes demonstrated different percentages of conservation among pathogenic and nonpathogenic strains. qPCR assays revealed differential expression among genes showing variable numbers of repetitive elements. In addition, repeats found in 206 genes already described to be differentially regulated under different culture conditions of M. hyopneumoniae strain 232 showed almost 80% conservation in relation to M. hyopneumoniae strain 7448 repeats. Altogether, these findings suggest a potential regulatory role of tandem and palindromic DNA repeats in the M. hyopneumoniae transcriptional profile. PMID:28005945

  14. MIMICRY, DIFFERENCE AND REPETITION

    Directory of Open Access Journals (Sweden)

    Marcelo Mendes de Souza

    2008-07-01

    Full Text Available This article addresses Homi K. Bhabha’s concept of mimicry in a broader context, other than that of cultural studies and post-colonial studies, bringing together other concepts, such as that of Gilles Deleuze in Difference and repetition, among other texts, and other names, such as Silviano Santiago, Jorge Luís Borges, Franz Kafka and Giorgio Agamben. As a partial conclusion, the article intends to oppose Bhabha’s freudian-marxist view to Five propositions on Psychoanalysis (1973, Gilles Deleuze’s text about Psychoanalysis published right after his book The Anti-Oedipus.

  15. Repetitive element hypermethylation in multiple sclerosis patients.

    Science.gov (United States)

    Neven, K Y; Piola, M; Angelici, L; Cortini, F; Fenoglio, C; Galimberti, D; Pesatori, A C; Scarpini, E; Bollati, V

    2016-06-18

    Multiple sclerosis (MS) is a complex disorder of the central nervous system whose cause is currently unknown. Evidence is increasing that DNA methylation alterations could be involved in inflammatory and neurodegenerative diseases and could contribute to MS pathogenesis. Repetitive elements Alu, LINE-1 and SAT-α, are widely known as estimators of global DNA methylation. We investigated Alu, LINE-1 and SAT-α methylation levels to evaluate their difference in a case-control setup and their role as a marker of disability. We obtained blood samples from 51 MS patients and 137 healthy volunteers matched by gender, age and smoking. Methylation was assessed using bisulfite-PCR-pyrosequencing. For all participants, medical history, physical and neurological examinations and screening laboratory tests were collected. All repetitive elements were hypermethylated in MS patients compared to healthy controls. A lower Expanded Disability Status Scale (EDSS) score was associated with a lower levels of LINE-1 methylation for 'EDSS = 1.0' and '1.5 ≤ EDSS ≤ 2.5' compared to an EDSS higher than 3, while Alu was associated with a higher level of methylation in these groups: 'EDSS = 1.0' and '1.5 ≤ EDSS ≤ 2.5'. MS patients exhibit an hypermethylation in repetitive elements compared to healthy controls. Alu and LINE-1 were associated with degree of EDSS score. Forthcoming studies focusing on epigenetics and the multifactorial pathogenetic mechanism of MS could elucidate these links further.

  16. Repetition in Waiting for Godot

    Institute of Scientific and Technical Information of China (English)

    李想; 魏妍

    2015-01-01

    Waiting for Godot is one of the most famous plays written by Samuel Barclay Beckett, and also is the founding work of“Theatre of the Absurd”. In the drama, repetitive phenomena shed light on the whole construction considerably. All the charac-ters were helpless and unthinking. Their dialogues were simple, nonsense and repetitive. Two scenes were cyclical. Repetition was used subtly in order to express the theme of the play, showing mental crisis after depravation of WWII.

  17. Understanding maximal repetitions in strings

    CERN Document Server

    Crochemore, Maxime

    2008-01-01

    The cornerstone of any algorithm computing all repetitions in a string of length n in O(n) time is the fact that the number of runs (or maximal repetitions) is O(n). We give a simple proof of this result. As a consequence of our approach, the stronger result concerning the linearity of the sum of exponents of all runs follows easily.

  18. Perceptual Repetition Blindness Effects

    Science.gov (United States)

    Hochhaus, Larry; Johnston, James C.; Null, Cynthia H. (Technical Monitor)

    1994-01-01

    The phenomenon of repetition blindness (RB) may reveal a new limitation on human perceptual processing. Recently, however, researchers have attributed RB to post-perceptual processes such as memory retrieval and/or reporting biases. The standard rapid serial visual presentation (RSVP) paradigm used in most RB studies is, indeed, open to such objections. Here we investigate RB using a "single-frame" paradigm introduced by Johnston and Hale (1984) in which memory demands are minimal. Subjects made only a single judgement about whether one masked target word was the same or different than a post-target probe. Confidence ratings permitted use of signal detection methods to assess sensitivity and bias effects. In the critical condition for RB a precue of the post-target word was provided prior to the target stimulus (identity precue), so that the required judgement amounted to whether the target did or did not repeat the precue word. In control treatments, the precue was either an unrelated word or a dummy.

  19. DNA

    Science.gov (United States)

    Stent, Gunther S.

    1970-01-01

    This history for molecular genetics and its explanation of DNA begins with an analysis of the Golden Jubilee essay papers, 1955. The paper ends stating that the higher nervous system is the one major frontier of biological inquiry which still offers some romance of research. (Author/VW)

  20. pRB Takes an EZ Path to a Repetitive Task.

    Science.gov (United States)

    Sanidas, Ioannis; Dyson, Nicholas J

    2016-12-15

    Repetitive DNA elements are essential for genome function; in this issue of Molecular Cell, Ishak et al. (2016) describe a novel mechanism of epigenetic repression at these elements that requires pRB-dependent recruitment of EZH2.

  1. Repetition in English Political Public Speaking

    Institute of Scientific and Technical Information of China (English)

    李红梅

    2010-01-01

    Repetition is frequently used in English political public speaking to make it easy to be remembered and powerful to move the feelings of the public. This paper is intended to analyze the functions of repetition and different levels of repetition to highlight the significance of repetition in English political public speaking and the ability of using it in practice.

  2. Varianish: Jamming with Pattern Repetition

    Directory of Open Access Journals (Sweden)

    Jort Band

    2014-10-01

    Full Text Available In music, patterns and pattern repetition are often regarded as a machine-like task, indeed often delegated to drum Machines and sequencers. Nevertheless, human players add subtle differences and variations to repeated patterns that are musically interesting and often unique. Especially when looking at minimal music, pattern repetitions create hypnotic effects and the human mind blends out the actual pattern to focus on variation and tiny differences over time. Varianish is a musical instrument that aims at turning this phenomenon into a new musical experience for musician and audience: Musical pattern repetitions are found in live music and Varianish generates additional (musical output accordingly that adds substantially to the overall musical expression. Apart from the theory behind the pattern finding and matching and the conceptual design, a demonstrator implementation of Varianish is presented and evaluated.

  3. REPETITIVE CLUSTER-TILTED ALGEBRAS

    Institute of Scientific and Technical Information of China (English)

    Zhang Shunhua; Zhang Yuehui

    2012-01-01

    Let H be a finite-dimensional hereditary algebra over an algebraically closed field k and CFm be the repetitive cluster category of H with m ≥ 1.We investigate the properties of cluster tilting objects in CFm and the structure of repetitive clustertilted algebras.Moreover,we generalize Theorem 4.2 in [12](Buan A,Marsh R,Reiten I.Cluster-tilted algebra,Trans.Amer.Math.Soc.,359(1)(2007),323-332.) to the situation of CFm,and prove that the tilting graph KCFm of CFm is connected.

  4. Repetitive elements in parasitic protozoa

    Directory of Open Access Journals (Sweden)

    Clayton Christine

    2010-05-01

    Full Text Available Abstract A recent paper published in BMC Genomics suggests that retrotransposition may be active in the human gut parasite Entamoeba histolytica. This adds to our knowledge of the various types of repetitive elements in parasitic protists and the potential influence of such elements on pathogenicity. See research article http://www.biomedcentral.com/1471-2164/11/321

  5. Repetition suppression and repetition priming are processing outcomes.

    Science.gov (United States)

    Wig, Gagan S

    2012-01-01

    Abstract There is considerable evidence that repetition suppression (RS) is a cortical signature of previous exposure to the environment. In many instances RS in specific brain regions is accompanied by improvements in specific behavioral measures; both observations are outcomes of repeated processing. In understanding the mechanism by which brain changes give rise to behavioral changes, it is important to consider what aspect of the environment a given brain area or set of areas processes, and how this might be expressed behaviorally.

  6. Cohesive Function of Lexical Repetition in Text

    Institute of Scientific and Technical Information of China (English)

    张莉; 卢沛沛

    2013-01-01

    Lexical repetition is the most direct form of lexical cohesion,which is the central device for making texts hang together. Although repetition is the most direct way to emphasize,it performs the cohesive effect more apparently.

  7. New Evidence for the Theory of Chromosome Organization by Repetitive Elements (CORE).

    Science.gov (United States)

    Tang, Shao-Jun

    2017-02-20

    Repetitive DNA elements were proposed to coordinate chromatin folding and interaction in chromosomes by their intrinsic homology-based clustering ability. A recent analysis of the data sets from chromosome-conformation-capture experiments confirms the spatial clustering of DNA repeats of the same family in the nuclear space, and thus provides strong new support for the CORE theory.

  8. Use of Long-Range Repetitive Element Polymorphism-PCR To Differentiate Bacillus anthracis Strains

    OpenAIRE

    Brumlik, Michael J.; Szymajda, Urszula; Zakowska, Dorota; Liang, Xudong; Redkar, Rajendra J.; Patra, Guy; Del Vecchio, Vito G.

    2001-01-01

    The genome of Bacillus anthracis is extremely monomorphic, and thus individual strains have often proven to be recalcitrant to differentiation at the molecular level. Long-range repetitive element polymorphism-PCR (LR REP-PCR) was used to differentiate various B. anthracis strains. A single PCR primer derived from a repetitive DNA element was able to amplify variable segments of a bacterial genome as large as 10 kb. We were able to characterize five genetically distinct groups by examining 10...

  9. Circuit considerations for repetitive railguns

    Energy Technology Data Exchange (ETDEWEB)

    Honih, E.M.

    1986-01-01

    Railgun electromagnetic launchers have significant military and scientific potential. They provide direct conversion of electrical energy to projectile kinetic energy, and they offer the hope of achieving projectile velocities greatly exceeding the limits of conventional guns. With over 10 km/sec already demonstrated, railguns are attracting attention for tactical and strategic weapons systems and for scientific equation-of-state research. The full utilization of railguns will require significant improvements in every aspect of system design - projectile, barrel, and power source - to achieve operation on a large scale. This paper will review fundamental aspects of railguns, with emphasis on circuit considerations and repetitive operation.

  10. DNA methylation

    DEFF Research Database (Denmark)

    Williams, Kristine; Christensen, Jesper; Helin, Kristian

    2012-01-01

    DNA methylation is involved in key cellular processes, including X-chromosome inactivation, imprinting and transcriptional silencing of specific genes and repetitive elements. DNA methylation patterns are frequently perturbed in human diseases such as imprinting disorders and cancer. The recent...... discovery that the three members of the TET protein family can convert 5-methylcytosine (5mC) into 5-hydroxymethylcytosine (5hmC) has provided a potential mechanism leading to DNA demethylation. Moreover, the demonstration that TET2 is frequently mutated in haematopoietic tumours suggests that the TET...... proteins are important regulators of cellular identity. Here, we review the current knowledge regarding the function of the TET proteins, and discuss various mechanisms by which they contribute to transcriptional control. We propose that the TET proteins have an important role in regulating DNA methylation...

  11. Digital repetitive control under varying frequency conditions

    OpenAIRE

    Ramos Fuentes, Germán Andrés

    2012-01-01

    The tracking/rejection of periodic signals constitutes a wide field of research in the control theory and applications area and Repetitive Control has proven to be an efficient way to face this topic; however, in some applications the period of the signal to be tracked/rejected changes in time or is uncertain, which causes and important performance degradation in the standard repetitive controller. This thesis presents some contributions to the open topic of repetitive control workin...

  12. [Repetition and fear of dying].

    Science.gov (United States)

    Lerner, B D

    1995-03-01

    In this paper a revision is made of the qualifications of Repetition (R) in Freuds work, i.e. its being at the service of the Pleasure Principle and, beyond it, the binding of free energy due to trauma. Freud intends to explain with this last concept the "fort-da" and the traumatic dreams (obsessively reiterated self-reproaches may be added to them). The main thesis of this work is that R. is not only a defense against the recollection of the ominous past (as in the metaphorical deaths of abandonment and desertion) but also a way of maintaining life and identify fighting against the inescapable omninous future (known but yet experienced), i.e. our own death. Some forms of R. like habits, identificatory behaviors and sometimes even magic, are geared to serve the life instinct. A literary illustration shows this desperate fight.

  13. Pressure rig for repetitive casting

    Science.gov (United States)

    Vasquez, Peter (Inventor); Hutto, William R. (Inventor); Philips, Albert R. (Inventor)

    1989-01-01

    The invention is a pressure rig for repetitive casting of metal. The pressure rig performs like a piston for feeding molten metal into a mold. Pressure is applied to an expandable rubber diaphragm which expands like a balloon to force the metal into the mold. A ceramic cavity which holds molten metal is lined with blanket-type insulating material, necessitating only a relining for subsequent use and eliminating the lengthy cavity preparation inherent in previous rigs. In addition, the expandable rubber diaphragm is protected by the insulating material thereby decreasing its vulnerability to heat damage. As a result of the improved design the life expectancy of the pressure rig contemplated by the present invention is more than doubled. Moreover, the improved heat protection has allowed the casting of brass and other alloys with higher melting temperatures than possible in the conventional pressure rigs.

  14. A study of methicillin - resistant staphylococcus aureus(MRSA) in a burn unit with repetitive - DNA - sequence- based PCR fingerprinting%烧伤病房耐甲氧西林金黄色葡萄球菌的DNA重复序列PCR研究

    Institute of Scientific and Technical Information of China (English)

    李洁; 徐秀华; 曾海涛

    2001-01-01

    目的研究烧伤病房耐甲氧西林金黄色葡萄球菌( methicillin - resistant Staphylococcus aureus,MRSA)的分布及传播,探讨烧伤病房医院感染的预防、监测及控制工作。方法采集烧伤患者的创面、鼻前庭,工作人员手、鼻前庭,陪护家属的手、鼻前庭及烧伤科病房各种环境表面共504份标本,从中分离到MRSA 58株,对苯唑西林敏感的金黄色葡萄球菌43株,并对所分离的MRSA菌株的基因组DNA进行重复序列PCR检测。结果 53.7%(22/41)的患者创面分离出MRSA,其中5例鼻前庭分离出MRSA;19名工作人员中,3人手分离出MRSA,工作人员鼻前庭未分离到MRSA;43例患者陪护家属中有9人手上分离出MRSA,2人鼻前庭分离出MRSA;193份环境标本共分离MRSA 13株。通过MRSA细菌基因组DNA重复序列PCR分析,发现部分患者创面之间及创面与工作人员、陪护和环境之间存在MRSA同源株。结论 (1)MRSA在烧伤科分布广,其中不乏同源株;(2)基因组DNA重复序列PCR分析,显示烧伤病室存在两例患者之间的交叉感染,MRSA在烧伤病房的传染源为患者,传播途径与陪护及工作人员的手污染有关;(3)MRSA的广泛存在,携带率高,手与环境的污染,是MRSA爆发感染的潜在危险。%bjective To investigate the distribution and spread of MRSA in a burn ward, so as to explore the measures of the prevention,surveillance and control of hospital infection in a burn ward. Methods Five hundred and four specimens were isolated from the wounds and nasal vestibules of burn patients ,the hands and nasal vestibules of medical staffs and lay attendants and the surfaces of various equipments. From these specimens,58 strains of MRSA and 43 methicillin- sensitive staphylococcus aureus (MSSA) were isolated. The genome DNA of isolated MRSA strains was analyzed by repetitive DNA - sequence- based PCR analysis. Results MRSA strains were isolated from the burn wounds

  15. Mammalian satellite DNA: a speaking dumb.

    Science.gov (United States)

    Enukashvily, Natella I; Ponomartsev, Nikita V

    2013-01-01

    The tandemly organized highly repetitive satellite DNA is the main DNA component of centromeric/pericentromeric constitutive heterochromatin. For almost a century, it was considered as "junk DNA," only a small portion of which is used for kinetochore formation. The current review summarizes recent data about satellite DNA transcription. The possible functions of the transcripts are discussed.

  16. Comparing repetition-based melody segmentation models

    NARCIS (Netherlands)

    Rodríguez López, M.E.; de Haas, Bas; Volk, Anja

    2014-01-01

    This paper reports on a comparative study of computational melody segmentation models based on repetition detection. For the comparison we implemented five repetition-based segmentation models, and subsequently evaluated their capacity to automatically find melodic phrase boundaries in a corpus of 2

  17. Task Repetition and Second Language Speech Processing

    Science.gov (United States)

    Lambert, Craig; Kormos, Judit; Minn, Danny

    2017-01-01

    This study examines the relationship between the repetition of oral monologue tasks and immediate gains in L2 fluency. It considers the effect of aural-oral task repetition on speech rate, frequency of clause-final and midclause filled pauses, and overt self-repairs across different task types and proficiency levels and relates these findings to…

  18. Repetitions: A Cross-Cultural Study.

    Science.gov (United States)

    Murata, Kumiko

    1995-01-01

    This study investigated how repetition is used in conversation among native speakers of British English, native speakers of Japanese, and Japanese speakers of English. Five interactional functions of repetition (interruption-orientated, solidarity, silence-avoidance, hesitation, and reformulation) were identified, as well as the cultural factors…

  19. Digital repetitive control under varying frequency conditions

    CERN Document Server

    Ramos, Germán A; Olm, Josep M

    2013-01-01

    The tracking/rejection of periodic signals constitutes a wide field of research in the control theory and applications area. Repetitive Control has proven to be an efficient way to face this topic. However, in some applications the frequency of the reference/disturbance signal is time-varying or uncertain. This causes an important performance degradation in the standard Repetitive Control scheme. This book presents some solutions to apply Repetitive Control in varying frequency conditions without loosing steady-state performance. It also includes a complete theoretical development and experimental results in two representative systems. The presented solutions are organized in two complementary branches: varying sampling period Repetitive Control and High Order Repetitive Control. The first approach allows dealing with large range frequency variations while the second allows dealing with small range frequency variations. The book also presents applications of the described techniques to a Roto-magnet plant and...

  20. Cold Spring Harbor symposia on quantitative biology. Volume XLVII, Part 1. Structures of DNA

    Energy Technology Data Exchange (ETDEWEB)

    1983-01-01

    The proceedings for the 47th Annual Cold Spring Harbor Symposia on Quantitative Biology are presented. This symposium focused on the Structure of DNA. Topics presented covered research in the handedness of DNA, conformational analysis, chemically modified DNA, chemical synthesis of DNA, DNA-protein interactions, DNA within nucleosomes, DNA methylation, DNA replication, gyrases and topoisomerases, recombining and mutating DNA, transcription of DNA and its regulation, the organization of genes along DNA, repetitive DNA and pseudogenes, and origins of replication, centromeres, and teleomeres.

  1. Strategies for Using Repetition as a Powerful Teaching Tool

    Science.gov (United States)

    Saville, Kirt

    2011-01-01

    Brain research indicates that repetition is of vital importance in the learning process. Repetition is an especially useful tool in the area of music education. The success of repetition can be enhanced by accurate and timely feedback. From "simple repetition" to "repetition with the addition or subtraction of degrees of freedom," there are many…

  2. Strategies for Using Repetition as a Powerful Teaching Tool

    Science.gov (United States)

    Saville, Kirt

    2011-01-01

    Brain research indicates that repetition is of vital importance in the learning process. Repetition is an especially useful tool in the area of music education. The success of repetition can be enhanced by accurate and timely feedback. From "simple repetition" to "repetition with the addition or subtraction of degrees of freedom," there are many…

  3. Repetition priming from moving faces.

    Science.gov (United States)

    Lander, Karen; Bruce, Vicki

    2004-06-01

    Recent experiments have suggested that seeing a familiar face move provides additional dynamic information to the viewer, useful in the recognition of identity. In four experiments, repetition priming was used to investigate whether dynamic information is intrinsic to the underlying face representations. The results suggest that a moving image primes more effectively than a static image, even when the same static image is shown in the prime and the test phases (Experiment 1). Furthermore, when moving images are presented in the test phase (Experiment 2), there is an advantage for moving prime images. The most priming advantage is found with naturally moving faces, rather than with those shown in slow motion (Experiment 3). Finally, showing the same moving sequence at prime and test produced more priming than that found when different moving sequences were shown (Experiment 4). The results suggest that dynamic information is intrinsic to the face representations and that there is an advantage to viewing the same moving sequence at prime and test.

  4. Precision markedly attenuates repetitive lift capacity.

    Science.gov (United States)

    Collier, Brooke R; Holland, Laura; McGhee, Deirdre; Sampson, John A; Bell, Alison; Stapley, Paul J; Groeller, Herbert

    2014-01-01

    This study investigated the effect of precision on time to task failure in a repetitive whole-body manual handling task. Twelve participants were required to repetitively lift a box weighing 65% of their single repetition maximum to shoulder height using either precise or unconstrained box placement. Muscle activity, forces exerted at the ground, 2D body kinematics, box acceleration and psychophysical measures of performance were recorded until task failure was reached. With precision, time to task failure for repetitive lifting was reduced by 72%, whereas the duration taken to complete a single lift and anterior deltoid muscle activation increased by 39% and 25%, respectively. Yet, no significant difference was observed in ratings of perceived exertion or heart rate at task failure. In conclusion, our results suggest that when accuracy is a characteristic of a repetitive manual handling task, physical work capacity will decline markedly. The capacity to lift repetitively to shoulder height was reduced by 72% when increased accuracy was required to place a box upon a shelf. Lifting strategy and muscle activity were also modified, confirming practitioners should take into consideration movement precision when evaluating the demands of repetitive manual handling tasks.

  5. Stability of repetitive-sequence PCR patterns with respect to culture age and subculture frequency.

    Science.gov (United States)

    Kang, Hyunseok Peter; Dunne, W Michael

    2003-06-01

    To examine the stability of repetitive-sequence (rep) PCR profiles, six species of bacteria were subcultured to blood agar plates and DNA was extracted from the cultures after 24, 48, and 72 h of incubation at 35 degrees C. In addition, the same species were subcultured to fresh blood plates daily and DNA was extracted from the cultures after growth of 5, 10, and 15 subcultures, respectively. rep PCR analysis demonstrated that all rep PCR fingerprints from a single species were identical.

  6. Repetitive elements dynamics in cell identity programming, maintenance and disease

    KAUST Repository

    Bodega, Beatrice

    2014-12-01

    The days of \\'junk DNA\\' seem to be over. The rapid progress of genomics technologies has been unveiling unexpected mechanisms by which repetitive DNA and in particular transposable elements (TEs) have evolved, becoming key issues in understanding genome structure and function. Indeed, rather than \\'parasites\\', recent findings strongly suggest that TEs may have a positive function by contributing to tissue specific transcriptional programs, in particular as enhancer-like elements and/or modules for regulation of higher order chromatin structure. Further, it appears that during development and aging genomes experience several waves of TEs activation, and this contributes to individual genome shaping during lifetime. Interestingly, TEs activity is major target of epigenomic regulation. These findings are shedding new light on the genome-phenotype relationship and set the premises to help to explain complex disease manifestation, as consequence of TEs activity deregulation.

  7. Refining borders of genome-rearrangements including repetitions

    Directory of Open Access Journals (Sweden)

    JA Arjona-Medina

    2016-10-01

    Full Text Available Abstract Background DNA rearrangement events have been widely studied in comparative genomic for many years. The importance of these events resides not only in the study about relatedness among different species, but also to determine the mechanisms behind evolution. Although there are many methods to identify genome-rearrangements (GR, the refinement of their borders has become a huge challenge. Until now no accepted method exists to achieve accurate fine-tuning: i.e. the notion of breakpoint (BP is still an open issue, and despite repeated regions are vital to understand evolution they are not taken into account in most of the GR detection and refinement methods. Methods and results We propose a method to refine the borders of GR including repeated regions. Instead of removing these repetitions to facilitate computation, we take advantage of them using a consensus alignment sequence of the repeated region in between two blocks. Using the concept of identity vectors for Synteny Blocks (SB and repetitions, a Finite State Machine is designed to detect transition points in the difference between such vectors. The method does not force the BP to be a region or a point but depends on the alignment transitions within the SBs and repetitions. Conclusion The accurate definition of the borders of SB and repeated genomic regions and consequently the detection of BP might help to understand the evolutionary model of species. In this manuscript we present a new proposal for such a refinement. Features of the SBs borders and BPs are different and fit with what is expected. SBs with more diversity in annotations and BPs short and richer in DNA replication and stress response, which are strongly linked with rearrangements.

  8. Chromosomal localization of two novel repetitive sequences isolated from the Chenopodium quinoa Willd. genome.

    Science.gov (United States)

    Kolano, B; Gardunia, B W; Michalska, M; Bonifacio, A; Fairbanks, D; Maughan, P J; Coleman, C E; Stevens, M R; Jellen, E N; Maluszynska, J

    2011-09-01

    The chromosomal organization of two novel repetitive DNA sequences isolated from the Chenopodium quinoa Willd. genome was analyzed across the genomes of selected Chenopodium species. Fluorescence in situ hybridization (FISH) analysis with the repetitive DNA clone 18-24J in the closely related allotetraploids C. quinoa and Chenopodium berlandieri Moq. (2n = 4x = 36) evidenced hybridization signals that were mainly present on 18 chromosomes; however, in the allohexaploid Chenopodium album L. (2n = 6x = 54), cross-hybridization was observed on all of the chromosomes. In situ hybridization with rRNA gene probes indicated that during the evolution of polyploidy, the chenopods lost some of their rDNA loci. Reprobing with rDNA indicated that in the subgenome labeled with 18-24J, one 35S rRNA locus and at least half of the 5S rDNA loci were present. A second analyzed sequence, 12-13P, localized exclusively in pericentromeric regions of each chromosome of C. quinoa and related species. The intensity of the FISH signals differed considerably among chromosomes. The pattern observed on C. quinoa chromosomes after FISH with 12-13P was very similar to GISH results, suggesting that the 12-13P sequence constitutes a major part of the repetitive DNA of C. quinoa.

  9. Contrasting the Chromosomal Organization of Repetitive DNAs in Two Gryllidae Crickets with Highly Divergent Karyotypes.

    Science.gov (United States)

    Palacios-Gimenez, Octavio M; Carvalho, Carlos Roberto; Ferrari Soares, Fernanda Aparecida; Cabral-de-Mello, Diogo C

    2015-01-01

    A large percentage of eukaryotic genomes consist of repetitive DNA that plays an important role in the organization, size and evolution. In the case of crickets, chromosomal variability has been found using classical cytogenetics, but almost no information concerning the organization of their repetitive DNAs is available. To better understand the chromosomal organization and diversification of repetitive DNAs in crickets, we studied the chromosomes of two Gryllidae species with highly divergent karyotypes, i.e., 2n(♂) = 29,X0 (Gryllus assimilis) and 2n = 9, neo-X1X2Y (Eneoptera surinamensis). The analyses were performed using classical cytogenetic techniques, repetitive DNA mapping and genome-size estimation. Conserved characteristics were observed, such as the occurrence of a small number of clusters of rDNAs and U snDNAs, in contrast to the multiple clusters/dispersal of the H3 histone genes. The positions of U2 snDNA and 18S rDNA are also conserved, being intermingled within the largest autosome. The distribution and base-pair composition of the heterochromatin and repetitive DNA pools of these organisms differed, suggesting reorganization. Although the microsatellite arrays had a similar distribution pattern, being dispersed along entire chromosomes, as has been observed in some grasshopper species, a band-like pattern was also observed in the E. surinamensis chromosomes, putatively due to their amplification and clustering. In addition to these differences, the genome of E. surinamensis is approximately 2.5 times larger than that of G. assimilis, which we hypothesize is due to the amplification of repetitive DNAs. Finally, we discuss the possible involvement of repetitive DNAs in the differentiation of the neo-sex chromosomes of E. surinamensis, as has been reported in other eukaryotic groups. This study provided an opportunity to explore the evolutionary dynamics of repetitive DNAs in two non-model species and will contribute to the understanding of

  10. Contrasting the Chromosomal Organization of Repetitive DNAs in Two Gryllidae Crickets with Highly Divergent Karyotypes.

    Directory of Open Access Journals (Sweden)

    Octavio M Palacios-Gimenez

    Full Text Available A large percentage of eukaryotic genomes consist of repetitive DNA that plays an important role in the organization, size and evolution. In the case of crickets, chromosomal variability has been found using classical cytogenetics, but almost no information concerning the organization of their repetitive DNAs is available. To better understand the chromosomal organization and diversification of repetitive DNAs in crickets, we studied the chromosomes of two Gryllidae species with highly divergent karyotypes, i.e., 2n(♂ = 29,X0 (Gryllus assimilis and 2n = 9, neo-X1X2Y (Eneoptera surinamensis. The analyses were performed using classical cytogenetic techniques, repetitive DNA mapping and genome-size estimation. Conserved characteristics were observed, such as the occurrence of a small number of clusters of rDNAs and U snDNAs, in contrast to the multiple clusters/dispersal of the H3 histone genes. The positions of U2 snDNA and 18S rDNA are also conserved, being intermingled within the largest autosome. The distribution and base-pair composition of the heterochromatin and repetitive DNA pools of these organisms differed, suggesting reorganization. Although the microsatellite arrays had a similar distribution pattern, being dispersed along entire chromosomes, as has been observed in some grasshopper species, a band-like pattern was also observed in the E. surinamensis chromosomes, putatively due to their amplification and clustering. In addition to these differences, the genome of E. surinamensis is approximately 2.5 times larger than that of G. assimilis, which we hypothesize is due to the amplification of repetitive DNAs. Finally, we discuss the possible involvement of repetitive DNAs in the differentiation of the neo-sex chromosomes of E. surinamensis, as has been reported in other eukaryotic groups. This study provided an opportunity to explore the evolutionary dynamics of repetitive DNAs in two non-model species and will contribute to the

  11. Repetitive Bibliographical Information in Relational Databases.

    Science.gov (United States)

    Brooks, Terrence A.

    1988-01-01

    Proposes a solution to the problem of loading repetitive bibliographic information in a microcomputer-based relational database management system. The alternative design described is based on a representational redundancy design and normalization theory. (12 references) (Author/CLB)

  12. Computer-Related Repetitive Stress Injuries

    Science.gov (United States)

    ... on the shoulder Epicondylitis: elbow soreness often called "tennis elbow" Ganglion cyst: swelling or lump in the wrist ... Bones, Muscles, and Joints Carpal Tunnel Syndrome Medial Epicondylitis Repetitive Stress Injuries Contact Us Print Resources Send ...

  13. Digital repetitive control under varying frequency conditions

    OpenAIRE

    Ramos Fuentes, Germán Andrés

    2012-01-01

    Premi extraordinari doctorat curs 2011-2012, àmbit d’Enginyeria Industrial The tracking/rejection of periodic signals constitutes a wide field of research in the control theory and applications area and Repetitive Control has proven to be an efficient way to face this topic; however, in some applications the period of the signal to be tracked/rejected changes in time or is uncertain, which causes and important performance degradation in the standard repetitive controller. This the...

  14. Unbiased K-mer Analysis Reveals Changes in Copy Number of Highly Repetitive Sequences During Maize Domestication and Improvement

    Science.gov (United States)

    Liu, Sanzhen; Zheng, Jun; Migeon, Pierre; Ren, Jie; Hu, Ying; He, Cheng; Liu, Hongjun; Fu, Junjie; White, Frank F.; Toomajian, Christopher; Wang, Guoying

    2017-01-01

    The major component of complex genomes is repetitive elements, which remain recalcitrant to characterization. Using maize as a model system, we analyzed whole genome shotgun (WGS) sequences for the two maize inbred lines B73 and Mo17 using k-mer analysis to quantify the differences between the two genomes. Significant differences were identified in highly repetitive sequences, including centromere, 45S ribosomal DNA (rDNA), knob, and telomere repeats. Genotype specific 45S rDNA sequences were discovered. The B73 and Mo17 polymorphic k-mers were used to examine allele-specific expression of 45S rDNA in the hybrids. Although Mo17 contains higher copy number than B73, equivalent levels of overall 45S rDNA expression indicates that transcriptional or post-transcriptional regulation mechanisms operate for the 45S rDNA in the hybrids. Using WGS sequences of B73xMo17 doubled haploids, genomic locations showing differential repetitive contents were genetically mapped, which displayed different organization of highly repetitive sequences in the two genomes. In an analysis of WGS sequences of HapMap2 lines, including maize wild progenitor, landraces, and improved lines, decreases and increases in abundance of additional sets of k-mers associated with centromere, 45S rDNA, knob, and retrotransposons were found among groups, revealing global evolutionary trends of genomic repeats during maize domestication and improvement. PMID:28186206

  15. 羊种布氏杆菌基因外重复回文序列经Toll样受体9诱导IFN-α表达的研究%The effects of repetitive extragenic palindromic sequences from Brucella melitensis DNA on the toll-like receptor 9-mediated interferon-α production

    Institute of Scientific and Technical Information of China (English)

    白丽云; 张雅娴; 王占黎; 王英; 于慧

    2015-01-01

    Objective To screen the repetitive extragenic palindromic sequences with activation of toll-like receptor 9(TLR9) activity from Brucella melitensis DNA,providing new ideas and new targets for prevention and treatment of brucellosis.Methods Bioinformatics methods were used to detect repetitive extragenic palindromic(REP) sequences from Brucella melitensis DNA.The studied REPs were selected and synthesized.RAW264.7 was cultured and transfected with REPs mediated by lipofectamine 3000.Additionally,TLR9-siRNA was used to downregulate TLR9 expression.The content of interferon-α(IFN-α) in the supernatant was then measured by ELISA.Results A total of 2 200 REP sequences in Brucella melitensis DNA were identified.Twelve REP sequences were synthesized for further detecting of the TLR9 agonistic activity.IFN-α expression in RAW264.7 treated with M2,M3,M4,M5,M6,M7,M9,M12 were (26.944 ± 1.868),(46.461 ± 2.562),(34.980 ± 2.055),(43.016 ± 2.162),(62.533 ± 4.031),(67.125 ± 5.069),(18.908 ± 1.633),(39.572 ± 2.465) pg/ml respectively,which significantly increased when compared with the negative control group [(12.594 ± 1.338) pg/ml,t =10.817,20.295,15.812,20.724,20.365,18.016,5.180,16.660,all P < 0.05].Additionally,TLR9-siRNA can significantly decrease the levels of IFN-α in RAW264.7 treated with M6.Conclusion REP sequences presented in Brucella melitensis DNA are able to induce IFN-α expression through TLR9,which can be helpful for the understanding of pathogenesis and immunity of Brucella melitensis.%目的 筛选具有活化Toll样受体9(TLR9)活性的羊种布氏杆菌DNA中基因外重复回文序列(REPs),检测其经TLR9诱导的干扰素-α(IFN-α)表达,为羊种布氏杆菌病的防治提供新思路.方法 针对羊种布氏杆菌Brucella melitensis NI基因组序列,利用生物信息学技术识别其REPs后,合成序列.将合成的天然骨架脱氧寡核苷酸(ODNs)转染小鼠单核巨噬细胞株RAW264.7,酶联免疫吸附测定法(ELISA)检测IFN

  16. The Prevalence and Phenomenology of Repetitive Behavior in Genetic Syndromes

    Science.gov (United States)

    Moss, Joanna; Oliver, Chris; Arron, Kate; Burbidge, Cheryl; Berg, Katy

    2009-01-01

    We investigated the prevalence and phenomenology of repetitive behavior in genetic syndromes to detail profiles of behavior. The Repetitive Behaviour Questionnaire (RBQ) provides fine-grained identification of repetitive behaviors. The RBQ was employed to examine repetitive behavior in Angelman (N = 104), Cornelia de Lange (N = 101), Cri-du-Chat…

  17. Likelihood methods and classical burster repetition

    CERN Document Server

    Graziani, C; Graziani, Carlo; Lamb, Donald Q

    1995-01-01

    We develop a likelihood methodology which can be used to search for evidence of burst repetition in the BATSE catalog, and to study the properties of the repetition signal. We use a simplified model of burst repetition in which a number N_{\\rm r} of sources which repeat a fixed number of times N_{\\rm rep} are superposed upon a number N_{\\rm nr} of non-repeating sources. The instrument exposure is explicitly taken into account. By computing the likelihood for the data, we construct a probability distribution in parameter space that may be used to infer the probability that a repetition signal is present, and to estimate the values of the repetition parameters. The likelihood function contains contributions from all the bursts, irrespective of the size of their positional errors --- the more uncertain a burst's position is, the less constraining is its contribution. Thus this approach makes maximal use of the data, and avoids the ambiguities of sample selection associated with data cuts on error circle size. We...

  18. The neurobiology of repetitive behavior : of mice…

    NARCIS (Netherlands)

    Langen, Marieke; Kas, Martien J H; Staal, Wouter G; van Engeland, Herman; Durston, Sarah

    2011-01-01

    Repetitive and stereotyped behavior is a prominent element of both animal and human behavior. Similar behavior is seen across species, in diverse neuropsychiatric disorders and in key phases of typical development. This raises the question whether these similar classes of behavior are caused by simi

  19. Large-scale detection of repetitions.

    Science.gov (United States)

    Smyth, W F

    2014-05-28

    Combinatorics on words began more than a century ago with a demonstration that an infinitely long string with no repetitions could be constructed on an alphabet of only three letters. Computing all the repetitions (such as ∙∙∙TTT ∙∙∙ or ∙∙∙ CGACGA ∙∙∙ ) in a given string x of length n is one of the oldest and most important problems of computational stringology, requiring time in the worst case. About a dozen years ago, it was discovered that repetitions can be computed as a by-product of the Θ(n)-time computation of all the maximal periodicities or runs in x. However, even though the computation is linear, it is also brute force: global data structures, such as the suffix array, the longest common prefix array and the Lempel-Ziv factorization, need to be computed in a preprocessing phase. Furthermore, all of this effort is required despite the fact that the expected number of runs in a string is generally a small fraction of the string length. In this paper, I explore the possibility that repetitions (perhaps also other regularities in strings) can be computed in a manner commensurate with the size of the output.

  20. Verbal Repetitions and Echolalia in Alzheimer's Discourse

    Science.gov (United States)

    Da Cruz, Fernanda Miranda

    2010-01-01

    This article reports on an investigation of echolalic repetition in Alzheimer's disease (AD). A qualitative analysis of data from spontaneous conversations with MHI, a woman with AD, is presented. The data come from the DALI Corpus, a corpus of spontaneous conversations involving subjects with AD. This study argues that echolalic effects can be…

  1. Neurobehavioural Correlates of Abnormal Repetitive Behaviour

    Directory of Open Access Journals (Sweden)

    R. A. Ford

    1991-01-01

    Full Text Available Conditions in which echolalia and echopraxia occur are reviewed, followed by an attempt to elicit possible mechanisms of these phenomena. A brief description of stereotypical and perseverative behaviour and obsessional phenomena is given. It is suggested that abnormal repetitive behaviour may occur partly as a result of central dopaminergic dysfunction.

  2. Reducing Repetitive Speech: Effects of Strategy Instruction.

    Science.gov (United States)

    Dipipi, Caroline M.; Jitendra, Asha K.; Miller, Judith A.

    2001-01-01

    This article describes an intervention with an 18-year-old young woman with mild mental retardation and a seizure disorder, which focused on her repetitive echolalic verbalizations. The intervention included time delay, differential reinforcement of other behaviors, and self-monitoring. Overall, the intervention was successful in facilitating…

  3. Verbal Repetitions and Echolalia in Alzheimer's Discourse

    Science.gov (United States)

    Da Cruz, Fernanda Miranda

    2010-01-01

    This article reports on an investigation of echolalic repetition in Alzheimer's disease (AD). A qualitative analysis of data from spontaneous conversations with MHI, a woman with AD, is presented. The data come from the DALI Corpus, a corpus of spontaneous conversations involving subjects with AD. This study argues that echolalic effects can be…

  4. Use of competitive PCR to assay copy number of repetitive elements in banana.

    Science.gov (United States)

    Baurens, F C; Noyer, J L; Lanaud, C; Lagoda, P J

    1996-11-27

    Banana is one of the most important subtropical fruit crops. Genetic improvement by traditional breeding strategies is difficult and better knowledge of genomic structure is needed. Repeated sequences are powerful markers for genetic fingerprinting. The method proposed here to determine the copy number of nuclear repetitive elements is based on competitive reverse transcription-polymerase chain reaction and can also be used for quantifying cytosolic sequences. The reliability of this method was investigated on crude preparations of total DNA. Variations due to the heterogeneity of crude DNA extracts showed that a single locus reference is needed for accurate quantification. A mapped microsatellite locus was used to normalize copy number measurements. Copy number assay of repetitive elements using this method clearly distinguishes between the two banana subspecies investigated: Musa acuminata spp. banskii and M. acuminata spp. malaccensis. Two repetitive sequence families, pMaCIR1115 and pA9-26, were assayed that cover up to 1% of the M. acuminata genome. Their copy number varied up to six fold between the two subspecies. Furthermore, sequence quantification showed that mitochondrial genomes are present in crude leaf-extracted banana DNA at up to 40 copies per cell.

  5. Robust Repetitive Controller for Fast AFM Imaging

    CERN Document Server

    Necipoglu, Serkan; Has, Yunus; Guvenc, Levent; Basdogan, Cagatay

    2012-01-01

    Currently, Atomic Force Microscopy (AFM) is the most preferred Scanning Probe Microscopy (SPM) method due to its numerous advantages. However, increasing the scanning speed and reducing the interaction forces between the probe's tip and the sample surface are still the two main challenges in AFM. To meet these challenges, we take advantage of the fact that the lateral movements performed during an AFM scan is a repetitive motion and propose a Repetitive Controller (RC) for the z-axis movements of the piezo-scanner. The RC utilizes the profile of the previous scan line while scanning the current line to achieve a better scan performance. The results of the scanning experiments performed with our AFM set-up show that the proposed RC significantly outperforms a conventional PI controller that is typically used for the same task. The scan error and the average tapping forces are reduced by 66% and 58%, respectively when the scan speed is increased by 7-fold.

  6. A repetitive elements perspective in Polycomb epigenetics.

    Directory of Open Access Journals (Sweden)

    Valentina eCasa

    2012-10-01

    Full Text Available Repetitive elements comprise over two-thirds of the human genome. For a long time, these elements have received little attention since they were considered non functional. On the contrary, recent evidence indicates that they play central roles in genome integrity, gene expression and disease. Indeed, repeats display meiotic instability associated with disease and are located within common fragile sites, which are hotspots of chromosome rearrangements in tumors. Moreover, a variety of diseases have been associated with aberrant transcription of repetitive elements. Overall this indicates that appropriate regulation of repetitive elements’ activity is fundamental.Polycomb group (PcG proteins are epigenetic regulators that are essential for the normal development of multicellular organisms. Mammalian PcG proteins are involved in fundamental processes, such as cellular memory, cell proliferation, genomic imprinting, X-inactivation, and cancer development. PcG proteins can convey their activity through long-distance interactions also on different chromosomes. This indicates that the 3D organization of PcG proteins contributes significantly to their function. However, it is still unclear how these complex mechanisms are orchestrated and which role PcG proteins play in the multi-level organization of gene regulation. Intriguingly, the greatest proportion of Polycomb-mediated chromatin modifications is located in genomic repeats and it has been suggested that they could provide a binding platform for Polycomb proteins.Here, these lines of evidence are woven together to discuss how repetitive elements could contribute to chromatin organization in the 3D nuclear space.

  7. Emotional arousal enhances word repetition priming

    OpenAIRE

    Thomas, Laura A.; LaBar, Kevin S.

    2005-01-01

    Three experiments were conducted to determine if emotional content increases repetition priming magnitude. In the study phase of Experiment 1, participants rated high-arousing negative (taboo) words and neutral words for concreteness. In the test phase, they made lexical decision judgements for the studied words intermixed with novel words (half taboo, half neutral) and pseudowords. In Experiment 2, low-arousing negative (LAN) words were substituted for the taboo words, and in Experiment 3 al...

  8. The Rhythms of Echo. Variations on Repetition

    Directory of Open Access Journals (Sweden)

    Rosa María Aradra Sánchez

    2015-04-01

    Full Text Available This paper presents a study on the echo as metric and rhetorical procedure. It makes a brief tour through some of the poetic manifestations of echo in the Spanish literary tradition, and a brief tour through the attention that metric theory has paid to this phenomenon. Then it stops at the possibilities that rhetoric offers for its analysis from the generic approach of the discursive repetition phenomena.

  9. Repetitive behaviour in autism: Imaging pathways and trajectories

    NARCIS (Netherlands)

    Langen, M.J.G.

    2009-01-01

    Repetitive behaviour in autism: Imaging pathways and trajectories Repetitive and rigid behaviour is one of the core symptoms of autism, a severe and lifelong child psychiatric disorder. Although repetitive behaviour symptoms often form a significant impairment for affected individuals, systematic st

  10. Neural Correlates of Restricted, Repetitive Behaviors in Autism Spectrum Disorders

    Science.gov (United States)

    2014-12-01

    Restrictive Repetitive Behaviors in Autism Spectrum Disorder . Authors: T.Q.Nguyen, B...Manoach. Functional Connectivity of the Dorsal Anterior Cingulate Cortex Predicts Restrictive Repetitive Behaviors in Autism Spectrum Disorder We...Introduction: Although restricted , repetitive behaviors (RRBs) are a highly disabling core feature of Autism Spectrum Disorders (ASDs), they

  11. Lingual Kinematics during Rapid Syllable Repetition in Parkinson's Disease

    Science.gov (United States)

    Wong, Min Ney; Murdoch, Bruce E.; Whelan, Brooke-Mai

    2012-01-01

    Background: Rapid syllable repetition tasks are commonly used in the assessment of motor speech disorders. However, little is known about the articulatory kinematics during rapid syllable repetition in individuals with Parkinson's disease (PD). Aims: To investigate and compare lingual kinematics during rapid syllable repetition in dysarthric…

  12. Modeling repetitive motions using structured light.

    Science.gov (United States)

    Xu, Yi; Aliaga, Daniel G

    2010-01-01

    Obtaining models of dynamic 3D objects is an important part of content generation for computer graphics. Numerous methods have been extended from static scenarios to model dynamic scenes. If the states or poses of the dynamic object repeat often during a sequence (but not necessarily periodically), we call such a repetitive motion. There are many objects, such as toys, machines, and humans, undergoing repetitive motions. Our key observation is that when a motion-state repeats, we can sample the scene under the same motion state again but using a different set of parameters; thus, providing more information of each motion state. This enables robustly acquiring dense 3D information difficult for objects with repetitive motions using only simple hardware. After the motion sequence, we group temporally disjoint observations of the same motion state together and produce a smooth space-time reconstruction of the scene. Effectively, the dynamic scene modeling problem is converted to a series of static scene reconstructions, which are easier to tackle. The varying sampling parameters can be, for example, structured-light patterns, illumination directions, and viewpoints resulting in different modeling techniques. Based on this observation, we present an image-based motion-state framework and demonstrate our paradigm using either a synchronized or an unsynchronized structured-light acquisition method.

  13. FRB repetition and non-Poissonian statistics

    CERN Document Server

    Connor, Liam; Oppermann, Niels

    2016-01-01

    We discuss some of the claims that have been made regarding the statistics of fast radio bursts (FRBs). In an earlier paper \\citep{2015arXiv150505535C} we conjectured that flicker noise associated with FRB repetition could show up in non-cataclysmic neutron star emission models, like supergiant pulses. We show how the current limits of repetition would be significantly weakened if their repeat rate really were non-Poissonian and had a pink or red spectrum. Repetition and its statistics have implications for observing strategy, generally favouring shallow wide-field surveys, since in the non-repeating scenario survey depth is unimportant. We also discuss the statistics of the apparent latitudinal dependence of FRBs, and offer a simple method for calculating the significance of this effect. We provide a generalized Bayesian framework for addressing this problem, which allows for direct model comparison. It is shown how the evidence for a steep latitudinal gradient of the FRB rate is less strong than initially s...

  14. Indices of methylation in sperm DNA from fertile men differ between distinct geographical regions

    NARCIS (Netherlands)

    Consales, C.; Leter, G.; Bonde, J. P E; Toft, G.; Eleuteri, P.; Moccia, T.; Budillon, A.; Jönsson, B. A G; Giwercman, A.; Pedersen, H. S.; Ludwicki, J. K.; Zviezdai, V.; Heederik, D.|info:eu-repo/dai/nl/072910542; Spanò, M.

    2014-01-01

    STUDY QUESTION Which are the main determinants, if any, of sperm DNA methylation levels? SUMMARY ANSWER Geographical region resulted associated with the sperm methylation status assessed on genome-wide repetitive sequences. WHAT IS KNOWN ALREADY DNA methylation level, assessed on repetitive sequence

  15. Indices of methylation in sperm DNA from fertile men differ between distinct geographical regions

    NARCIS (Netherlands)

    Consales, C.; Leter, G.; Bonde, J. P E; Toft, G.; Eleuteri, P.; Moccia, T.; Budillon, A.; Jönsson, B. A G; Giwercman, A.; Pedersen, H. S.; Ludwicki, J. K.; Zviezdai, V.; Heederik, D.; Spanò, M.

    2014-01-01

    STUDY QUESTION Which are the main determinants, if any, of sperm DNA methylation levels? SUMMARY ANSWER Geographical region resulted associated with the sperm methylation status assessed on genome-wide repetitive sequences. WHAT IS KNOWN ALREADY DNA methylation level, assessed on repetitive sequence

  16. fMRI repetition suppression: neuronal adaptation or stimulus expectation?

    Science.gov (United States)

    Larsson, Jonas; Smith, Andrew T

    2012-03-01

    Measurements of repetition suppression with functional magnetic resonance imaging (fMRI adaptation) have been used widely to probe neuronal population response properties in human cerebral cortex. fMRI adaptation techniques assume that fMRI repetition suppression reflects neuronal adaptation, an assumption that has been challenged on the basis of evidence that repetition-related response changes may reflect unrelated factors, such as attention and stimulus expectation. Specifically, Summerfield et al. (Summerfield C, Trittschuh EH, Monti JM, Mesulam MM, Egner T. 2008. Neural repetition suppression reflects fulfilled perceptual expectations. Nat Neurosci. 11:1004-1006) reported that the relative frequency of stimulus repetitions and non-repetitions influenced the magnitude of repetition suppression in the fusiform face area, suggesting that stimulus expectation accounted for most of the effect of repetition. We confirm that stimulus expectation can significantly influence fMRI repetition suppression throughout visual cortex and show that it occurs with long as well as short adaptation durations. However, the effect was attention dependent: When attention was diverted away from the stimuli, the effects of stimulus expectation completely disappeared. Nonetheless, robust and significant repetition suppression was still evident. These results suggest that fMRI repetition suppression reflects a combination of neuronal adaptation and attention-dependent expectation effects that can be experimentally dissociated. This implies that with an appropriate experimental design, fMRI adaptation can provide valid measures of neuronal adaptation and hence response specificity.

  17. Storytelling and Repetitive Narratives for Design Empathy

    DEFF Research Database (Denmark)

    Fritsch, Jonas; Judice, Andrea; Soini, Katja

    2007-01-01

    Today it is widely established in design research that empathy is an important part of creating a true understanding of user experience as a resource for design. A typical challenge is how to transmit the feeling of empathy acquired by user studies to designers who have not participated in the user...... study. In this paper, we show how we attained an empathic understanding through storytelling and aroused empathy to others using repetitive narratives in an experimental presentation bringing forth factual, reflective and experiential aspects of the user information. Taking as a starting point our...... experiences with the design project Suomenlinna Seclusive, we conclude with the potential of using narratives for invoking design empathy....

  18. A miniature high repetition rate shock tube.

    Science.gov (United States)

    Tranter, R S; Lynch, P T

    2013-09-01

    A miniature high repetition rate shock tube with excellent reproducibility has been constructed to facilitate high temperature, high pressure, gas phase experiments at facilities such as synchrotron light sources where space is limited and many experiments need to be averaged to obtain adequate signal levels. The shock tube is designed to generate reaction conditions of T > 600 K, P shock waves with predictable characteristics are created, repeatably. Two synchrotron-based experiments using this apparatus are also briefly described here, demonstrating the potential of the shock tube for research at synchrotron light sources.

  19. Storytelling and Repetitive Narratives for Design Empathy

    DEFF Research Database (Denmark)

    Fritsch, Jonas; Judice, Andrea; Soini, Katja

    2007-01-01

    Today it is widely established in design research that empathy is an important part of creating a true understanding of user experience as a resource for design. A typical challenge is how to transmit the feeling of empathy acquired by user studies to designers who have not participated in the user...... study. In this paper, we show how we attained an empathic understanding through storytelling and aroused empathy to others using repetitive narratives in an experimental presentation bringing forth factual, reflective and experiential aspects of the user information. Taking as a starting point our...... experiences with the design project Suomenlinna Seclusive, we conclude with the potential of using narratives for invoking design empathy....

  20. The repetitive component of the sunflower genome

    Directory of Open Access Journals (Sweden)

    T. Giordani

    2014-08-01

    Full Text Available The sunflower (Helianthus annuus and species belonging to the genus Helianthus are emerging as a model species and genus for a number of studies on genome evolution. In this review, we report on the repetitive component of the H. annuus genome at the biochemical, molecular, cytological, and genomic levels. Recent work on sunflower genome composition is described, with emphasis on different types of repeat sequences, especially LTR-retrotransposons, of which we report on isolation, characterisation, cytological localisation, transcription, dynamics of proliferation, and comparative analyses within the genus Helianthus.

  1. Organization of some repetitive DNAs and B chromosomes in the grasshopper Eumastusia koebelei koebelei (Rehn, 1909) (Orthoptera, Acrididae, Leptysminae)

    Science.gov (United States)

    Anjos, Allison; Loreto, Vilma; Cabral-de-Mello, Diogo C.

    2016-01-01

    Abstract B chromosomes occur in approximately 15% of eukaryotes and are usually heterochromatic and rich in repetitive DNAs. Here we describe characteristics of a B chromosome in the grasshopper Eumastusia koebelei koebelei (Rehn, 1909) through classical cytogenetic methods and mapping of some repetitive DNAs, including multigene families, telomeric repeats and a DNA fraction enriched with repetitive DNAs obtained from DOP-PCR. Eumastusia koebelei koebelei presented 2n=23, X0 and, in one individual, two copies of the same variant of a B chromosome were noticed, which are associated during meiosis. The C-positive blocks were located in the pericentromeric regions of the standard complement and along the entire length of the B chromosomes. Some G+C-rich heterochromatic blocks were noticed, including conspicuous blocks in the B chromosomes. The mapping of 18S rDNA and U2 snDNA revealed only autosomal clusters, and the telomeric probe hybridized in terminal regions. Finally, the DOP-PCR probe obtained from an individual without a B chromosome revealed signals in the heterochromatic regions, including the entire length of the B chromosome. The possible intraspecific origin of the B chromosomes, due to the shared pool of repetitive DNAs between the A and B chromosomes and the possible consequences of their association are discussed. PMID:27551344

  2. Chromosomal Mapping of Repetitive DNAs in Triportheus trifurcatus (Characidae, Characiformes): Insights into the Differentiation of the Z and W Chromosomes

    Science.gov (United States)

    Yano, Cassia Fernanda; Poltronieri, Juliana; Bertollo, Luiz Antonio Carlos; Artoni, Roberto Ferreira; Liehr, Thomas; de Bello Cioffi, Marcelo

    2014-01-01

    Repetitive DNA sequences play an important role in the structural and functional organization of chromosomes, especially in sex chromosome differentiation. The genus Triportheus represents an interesting model for such studies because all of its species analyzed so far contain a ZZ/ZW sex chromosome system. A close relationship has been found between the differentiation of the W chromosome and heterochromatinization, with the involvement of different types of repetitive DNA in this process. This study investigated several aspects of this association in the W chromosome of Triportheus trifurcatus (2n = 52 chromosomes), including the cytogenetic mapping of repetitive DNAs such as telomeric sequences (TTAGGG)n, microsatellites and retrotransposons. A remarkable heterochromatic segment on the W chromosome was observed with a preferential accumulation of (CAC)10, (CAG)10, (CGG)10, (GAA)10 and (TA)15. The retrotransposons Rex1 and Rex3 showed a general distribution pattern in the chromosomes, and Rex6 showed a different distribution on the W chromosome. The telomeric repeat (TTAGGG)n was highly evident in both telomeres of all chromosomes without the occurrence of ITS. Thus, the differentiation of the W chromosome of T. trifurcatus is clearly associated with the formation of heterochromatin and different types of repetitive DNA, suggesting that these elements had a prominent role in this evolutionary process. PMID:24632562

  3. Comparative molecular cytogenetics of major repetitive sequence families of three Dendrobium species (Orchidaceae) from Bangladesh

    Science.gov (United States)

    Begum, Rabeya; Alam, Sheikh Shamimul; Menzel, Gerhard; Schmidt, Thomas

    2009-01-01

    Background and Aims Dendrobium species show tremendous morphological diversity and have broad geographical distribution. As repetitive sequence analysis is a useful tool to investigate the evolution of chromosomes and genomes, the aim of the present study was the characterization of repetitive sequences from Dendrobium moschatum for comparative molecular and cytogenetic studies in the related species Dendrobium aphyllum, Dendrobium aggregatum and representatives from other orchid genera. Methods In order to isolate highly repetitive sequences, a c0t-1 DNA plasmid library was established. Repeats were sequenced and used as probes for Southern hybridization. Sequence divergence was analysed using bioinformatic tools. Repetitive sequences were localized along orchid chromosomes by fluorescence in situ hybridization (FISH). Key Results Characterization of the c0t-1 library resulted in the detection of repetitive sequences including the (GA)n dinucleotide DmoO11, numerous Arabidopsis-like telomeric repeats and the highly amplified dispersed repeat DmoF14. The DmoF14 repeat is conserved in six Dendrobium species but diversified in representative species of three other orchid genera. FISH analyses showed the genome-wide distribution of DmoF14 in D. moschatum, D. aphyllum and D. aggregatum. Hybridization with the telomeric repeats demonstrated Arabidopsis-like telomeres at the chromosome ends of Dendrobium species. However, FISH using the telomeric probe revealed two pairs of chromosomes with strong intercalary signals in D. aphyllum. FISH showed the terminal position of 5S and 18S–5·8S–25S rRNA genes and a characteristic number of rDNA sites in the three Dendrobium species. Conclusions The repeated sequences isolated from D. moschatum c0t-1 DNA constitute major DNA families of the D. moschatum, D. aphyllum and D. aggregatum genomes with DmoF14 representing an ancient component of orchid genomes. Large intercalary telomere-like arrays suggest chromosomal

  4. The role of short-term memory impairment in nonword repetition, real word repetition, and nonword decoding: A case study.

    Science.gov (United States)

    Peter, Beate

    2017-09-21

    In a companion study, adults with dyslexia and adults with a probable history of childhood apraxia of speech showed evidence of difficulty with processing sequential information during nonword repetition, multisyllabic real word repetition and nonword decoding. Results suggested that some errors arose in visual encoding during nonword reading, all levels of processing but especially short-term memory storage/retrieval during nonword repetition, and motor planning and programming during complex real word repetition. To further investigate the role of short-term memory, a participant with short-term memory impairment (MI) was recruited. MI was confirmed with poor performance during a sentence repetition and three nonword repetition tasks, all of which have a high short-term memory load, whereas typical performance was observed during tests of reading, spelling, and static verbal knowledge, all with low short-term memory loads. Experimental results show error-free performance during multisyllabic real word repetition but high counts of sequence errors, especially migrations and assimilations, during nonword repetition, supporting short-term memory as a locus of sequential processing deficit during nonword repetition. Results are also consistent with the hypothesis that during complex real word repetition, short-term memory is bypassed as the word is recognized and retrieved from long-term memory prior to producing the word.

  5. A phonetic approach to consonant repetition in early words.

    Science.gov (United States)

    Kim, Namhee; Davis, Barbara L

    2015-08-01

    The goal of this study was to evaluate movement-based principles for understanding early speech output patterns. Consonant repetition patterns within children's actual productions of word forms were analyzed using spontaneous speech data from 10 typically developing American-English learning children between 12 and 36 months of age. Place of articulation, word level patterns, and developmental trends in CVC and CVCV repeated word forms were evaluated. Labial and coronal place repetitions dominated. Regressive repetition (e.g., [gag] for "dog") occurred frequently in CVC but not in CVCV word forms. Consonant repetition decreased over time. However, the children produced sound types available reported as being within young children's production system capabilities in consonant repetitions in all time periods. Findings suggest that a movement-based approach can provide a framework for comprehensively characterizing consonant place repetition patterns in early speech development.

  6. Repetition and Reactance in Graham’s "Underneath" Poems

    Directory of Open Access Journals (Sweden)

    Roghayeh Farsi

    2017-09-01

    Full Text Available The present paper gives a detailed analysis and interpretation of 16 poems in Jorie Graham's collection, Swarm (2000, which bear "UNDERNEATH" as their main titles. The poems are marked with different types of repetition such as graphological repetition, word, phrase, and sentential repetition, semantic repetition, and syntactic repetition. The study draws on Lakoff and Johnson's theories on metaphor and Brehm and Brehm’s reactance theory. It is argued "underneath" is a conceptual (orientational metaphor which signifies a state of being limited, lack of control and freedom, and loss of power. The paper investigates the speaker's reactant behavior in "Underneath" poems, seeking a way to restore her lost freedom. Reactance behaviors can be skepticism, inertia, aggression, and resistance. It is concluded despite her thematic inertia, representing her submission to the oppressed state, her stylistic reactance reflected in repetitions, innovations, and disruptive diction stands for her attempts to regain her lost control.

  7. ReRep: Computational detection of repetitive sequences in genome survey sequences (GSS

    Directory of Open Access Journals (Sweden)

    Alves-Ferreira Marcelo

    2008-09-01

    Full Text Available Abstract Background Genome survey sequences (GSS offer a preliminary global view of a genome since, unlike ESTs, they cover coding as well as non-coding DNA and include repetitive regions of the genome. A more precise estimation of the nature, quantity and variability of repetitive sequences very early in a genome sequencing project is of considerable importance, as such data strongly influence the estimation of genome coverage, library quality and progress in scaffold construction. Also, the elimination of repetitive sequences from the initial assembly process is important to avoid errors and unnecessary complexity. Repetitive sequences are also of interest in a variety of other studies, for instance as molecular markers. Results We designed and implemented a straightforward pipeline called ReRep, which combines bioinformatics tools for identifying repetitive structures in a GSS dataset. In a case study, we first applied the pipeline to a set of 970 GSSs, sequenced in our laboratory from the human pathogen Leishmania braziliensis, the causative agent of leishmaniosis, an important public health problem in Brazil. We also verified the applicability of ReRep to new sequencing technologies using a set of 454-reads of an Escheria coli. The behaviour of several parameters in the algorithm is evaluated and suggestions are made for tuning of the analysis. Conclusion The ReRep approach for identification of repetitive elements in GSS datasets proved to be straightforward and efficient. Several potential repetitive sequences were found in a L. braziliensis GSS dataset generated in our laboratory, and further validated by the analysis of a more complete genomic dataset from the EMBL and Sanger Centre databases. ReRep also identified most of the E. coli K12 repeats prior to assembly in an example dataset obtained by automated sequencing using 454 technology. The parameters controlling the algorithm behaved consistently and may be tuned to the properties

  8. FEMA Hazard Mitigation Assistance Repetitive Flood Claims (RFC) Data

    Data.gov (United States)

    Department of Homeland Security — This dataset contains closed and obligated projects funded under the following Hazard Mitigation Assistance (HMA) grant programs: Repetitive Flood Claims (RFC). The...

  9. A review of neuroimaging findings in repetitive brain trauma.

    Science.gov (United States)

    Koerte, Inga K; Lin, Alexander P; Willems, Anna; Muehlmann, Marc; Hufschmidt, Jakob; Coleman, Michael J; Green, Isobel; Liao, Huijun; Tate, David F; Wilde, Elisabeth A; Pasternak, Ofer; Bouix, Sylvain; Rathi, Yogesh; Bigler, Erin D; Stern, Robert A; Shenton, Martha E

    2015-05-01

    Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease confirmed at postmortem. Those at highest risk are professional athletes who participate in contact sports and military personnel who are exposed to repetitive blast events. All neuropathologically confirmed CTE cases, to date, have had a history of repetitive head impacts. This suggests that repetitive head impacts may be necessary for the initiation of the pathogenetic cascade that, in some cases, leads to CTE. Importantly, while all CTE appears to result from repetitive brain trauma, not all repetitive brain trauma results in CTE. Magnetic resonance imaging has great potential for understanding better the underlying mechanisms of repetitive brain trauma. In this review, we provide an overview of advanced imaging techniques currently used to investigate brain anomalies. We also provide an overview of neuroimaging findings in those exposed to repetitive head impacts in the acute/subacute and chronic phase of injury and in more neurodegenerative phases of injury, as well as in military personnel exposed to repetitive head impacts. Finally, we discuss future directions for research that will likely lead to a better understanding of the underlying mechanisms separating those who recover from repetitive brain trauma vs. those who go on to develop CTE.

  10. FEMA Hazard Mitigation Assistance Severe Repetitive Loss (SRL) Data

    Data.gov (United States)

    Department of Homeland Security — This dataset contains closed and obligated projects funded under the following Hazard Mitigation Assistance (HMA) grant programs: Severe Repetitive Loss (SRL). The...

  11. Advances in Research on Hepatitis B Virus DNA Integration

    Institute of Scientific and Technical Information of China (English)

    Ju-sheng LIN; Lin-lin GAO

    2008-01-01

    Since HBV DNA integration was discovered for the first time in 1980, various methods have been used to detect and study it, such as Southern Blot, in situ hybridization, polymerase chain reaction and so on. HBV DNA integration is thought to be random on the whole although some hot spots of integration were described by some researchers, one of which might be the repetitive sequences of the genomic DNA. Besides, DNA damage, especially double-strand breaks could promote HBV DNA integration into host genome. HBV DNA integration into cells may damage the stability of the genome, cause DNA rearrangement, promote DNA deletion and induce the formation of HCC.

  12. Repetitive control of electrically driven robot manipulators

    Science.gov (United States)

    Fateh, Mohammad Mehdi; Ahsani Tehrani, Hojjat; Karbassi, Seyed Mehdi

    2013-04-01

    This article presents a novel robust discrete repetitive control of electrically driven robot manipulators for tracking of a periodic trajectory. We propose a novel model, which presents the highly non-linear dynamics of robot manipulator in the form of linear discrete-time time-varying system. Based on the proposed model, we develop a two-term control law. The first term is an ordinary time-optimal and minimum-norm (TOMN) control by employing parametric controllers to guarantee stability. The second term is a novel robust control to improve the control performance in the face of uncertainties. The robust control estimates and compensates uncertainties including the parametric uncertainty, unmodelled dynamics and external disturbances. Performance of the proposed method is compared with two discrete methods, namely the TOMN control and an adaptive iterative learning (AIL) control. Simulation results confirm superiority of the proposed method in terms of the convergence speed and precision.

  13. Studies of the uncanny: the repetition factor

    Directory of Open Access Journals (Sweden)

    Julia Teitelroit Martins

    2011-06-01

    Full Text Available Freud’s essay The Uncanny (Das Unheimliche offers many indications for the comprehension of an aesthetics of the uncanny which deserve to be explored. Nonetheless, a concept traverses it from beginning to end: the return – which enables its reading under the light of Beyond the pleasure principle, written along the same span of time. Emphasis is given to the uncanny in the sense of repetition of the different – a paradox in terms, like the strangely familiar uncanny. In order to test the validity of an aesthetic reading under this perspective, follows an analysis of the brief short story “A terceira margem do rio” (“The third margin of the river”, by Guimarães Rosa.

  14. Object color affects identification and repetition priming.

    Science.gov (United States)

    Uttl, Bob; Graf, Peter; Santacruz, Pilar

    2006-10-01

    We investigated the influence of color on the identification of both non-studied and studied objects. Participants studied black and white and color photos of common objects and memory was assessed with an identification test. Consistent with our meta-analysis of prior research, we found that objects were easier to identify from color than from black and white photos. We also found substantial priming in all conditions, and study-to-test changes in an object's color reduced the magnitude of priming. Color-specific priming effects were large for color-complex objects, but minimal for color-simple objects. The pattern and magnitude of priming effects was not influenced either by the extent to which an object always appears in the same color (i.e., whether a color is symptomatic of an object) or by the object's origin (natural versus fabricated). We discuss the implications of our findings for theoretical accounts of object perception and repetition priming.

  15. Annotation, submission and screening of repetitive elements in Repbase: RepbaseSubmitter and Censor

    Directory of Open Access Journals (Sweden)

    Hankus Lukasz

    2006-10-01

    Full Text Available Abstract Background Repbase is a reference database of eukaryotic repetitive DNA, which includes prototypic sequences of repeats and basic information described in annotations. Updating and maintenance of the database requires specialized tools, which we have created and made available for use with Repbase, and which may be useful as a template for other curated databases. Results We describe the software tools RepbaseSubmitter and Censor, which are designed to facilitate updating and screening the content of Repbase. RepbaseSubmitter is a java-based interface for formatting and annotating Repbase entries. It eliminates many common formatting errors, and automates actions such as calculation of sequence lengths and composition, thus facilitating curation of Repbase sequences. In addition, it has several features for predicting protein coding regions in sequences; searching and including Pubmed references in Repbase entries; and searching the NCBI taxonomy database for correct inclusion of species information and taxonomic position. Censor is a tool to rapidly identify repetitive elements by comparison to known repeats. It uses WU-BLAST for speed and sensitivity, and can conduct DNA-DNA, DNA-protein, or translated DNA-translated DNA searches of genomic sequence. Defragmented output includes a map of repeats present in the query sequence, with the options to report masked query sequence(s, repeat sequences found in the query, and alignments. Conclusion Censor and RepbaseSubmitter are available as both web-based services and downloadable versions. They can be found at http://www.girinst.org/repbase/submission.html (RepbaseSubmitter and http://www.girinst.org/censor/index.php (Censor.

  16. Ancient DNA

    DEFF Research Database (Denmark)

    Willerslev, Eske; Cooper, Alan

    2004-01-01

    ancient DNA, palaeontology, palaeoecology, archaeology, population genetics, DNA damage and repair......ancient DNA, palaeontology, palaeoecology, archaeology, population genetics, DNA damage and repair...

  17. Repetitive sequences and epigenetic modification: inseparable partners play important roles in the evolution of plant sex chromosomes.

    Science.gov (United States)

    Li, Shu-Fen; Zhang, Guo-Jun; Yuan, Jin-Hong; Deng, Chuan-Liang; Gao, Wu-Jun

    2016-05-01

    The present review discusses the roles of repetitive sequences played in plant sex chromosome evolution, and highlights epigenetic modification as potential mechanism of repetitive sequences involved in sex chromosome evolution. Sex determination in plants is mostly based on sex chromosomes. Classic theory proposes that sex chromosomes evolve from a specific pair of autosomes with emergence of a sex-determining gene(s). Subsequently, the newly formed sex chromosomes stop recombination in a small region around the sex-determining locus, and over time, the non-recombining region expands to almost all parts of the sex chromosomes. Accumulation of repetitive sequences, mostly transposable elements and tandem repeats, is a conspicuous feature of the non-recombining region of the Y chromosome, even in primitive one. Repetitive sequences may play multiple roles in sex chromosome evolution, such as triggering heterochromatization and causing recombination suppression, leading to structural and morphological differentiation of sex chromosomes, and promoting Y chromosome degeneration and X chromosome dosage compensation. In this article, we review the current status of this field, and based on preliminary evidence, we posit that repetitive sequences are involved in sex chromosome evolution probably via epigenetic modification, such as DNA and histone methylation, with small interfering RNAs as the mediator.

  18. Evolution of repetitive proteins: spider silks from Nephila clavipes (Tetragnathidae) and Araneus bicentenarius (Araneidae).

    Science.gov (United States)

    Beckwitt, R; Arcidiacono, S; Stote, R

    1998-03-01

    Spider silks are highly repetitive proteins, characterized by regions of polyalanine and glycine-rich repeating units. We have obtained two variants of the Spidroin 1 (NCF-1) silk gene sequence from Nephila clavipes. One sequence (1726 bp) was from a cloned cDNA, and the other (1951 bp) was from PCR of genomic DNA. When these sequences are compared with each other and the previously published Spidroin 1 sequence, there are differences due to sequence rearrangements, as well as single base substitutions. These variations are similar to those that have been reported from other highly repetitive genes, and probably represent the results of unequal cross-overs. We have also obtained 708 bp of sequence from pCR of genomic DNA from Araneus biocentenarius. This sequence shows considerable similarity to a dragline sequence (ADF-3) from A. diadematus, as well as Spidroin 2 (NCF-2) from N. clavipes. Minor but consistent differences in the repeating unit sequence between A. bicentenarius and A. diadematus suggest that concerted evolution or gene conversion processes are acting to maintain similarity among repeat units within a single gene.

  19. Next-generation sequencing detects repetitive elements expansion in giant genomes of annual killifish genus Austrolebias (Cyprinodontiformes, Rivulidae).

    Science.gov (United States)

    García, G; Ríos, N; Gutiérrez, V

    2015-06-01

    Among Neotropical fish fauna, the South American killifish genus Austrolebias (Cyprinodontiformes: Rivulidae) constitutes an excellent model to study the genomic evolutionary processes underlying speciation events. Recently, unusually large genome size has been described in 16 species of this genus, with an average DNA content of about 5.95 ± 0.45 pg per diploid cell (mean C-value of about 2.98 pg). In the present paper we explore the possible origin of this unparallel genomic increase by means of comparative analysis of the repetitive components using NGS (454-Roche) technology in the lowest and highest Rivulidae genomes. Here, we provide the first annotated Rivulidae-repeated sequences composition and their relative repetitive fraction in both genomes. Remarkably, the genomic proportion of the moderately repetitive DNA in Austrolebias charrua genome represents approximately twice (45%) of the repetitive components of the highly related rivulinae taxon Cynopoecilus melanotaenia (25%). Present work provides evidence about the impact of the repeat families that could be distinctly proliferated among sublineages within Rivulidae fish group, explaining the great genome size differences encompassing the differentiation and speciation events in this family.

  20. The golden ratio of gait harmony: repetitive proportions of repetitive gait phases.

    Science.gov (United States)

    Iosa, Marco; Fusco, Augusto; Marchetti, Fabio; Morone, Giovanni; Caltagirone, Carlo; Paolucci, Stefano; Peppe, Antonella

    2013-01-01

    In nature, many physical and biological systems have structures showing harmonic properties. Some of them were found related to the irrational number φ known as the golden ratio that has important symmetric and harmonic properties. In this study, the spatiotemporal gait parameters of 25 healthy subjects were analyzed using a stereophotogrammetric system with 25 retroreflective markers located on their skin. The proportions of gait phases were compared with φ, the value of which is about 1.6180. The ratio between the entire gait cycle and stance phase resulted in 1.620 ± 0.058, that between stance and the swing phase was 1.629 ± 0.173, and that between swing and the double support phase was 1.684 ± 0.357. All these ratios did not differ significantly from each other (F = 0.870, P = 0.422, repeated measure analysis of variance) or from φ (P = 0.670, 0.820, 0.422, resp., t-tests). The repetitive gait phases of physiological walking were found in turn in repetitive proportions with each other, revealing an intrinsic harmonic structure. Harmony could be the key for facilitating the control of repetitive walking. Harmony is a powerful unifying factor between seemingly disparate fields of nature, including human gait.

  1. The Golden Ratio of Gait Harmony: Repetitive Proportions of Repetitive Gait Phases

    Directory of Open Access Journals (Sweden)

    Marco Iosa

    2013-01-01

    Full Text Available In nature, many physical and biological systems have structures showing harmonic properties. Some of them were found related to the irrational number known as the golden ratio that has important symmetric and harmonic properties. In this study, the spatiotemporal gait parameters of 25 healthy subjects were analyzed using a stereophotogrammetric system with 25 retroreflective markers located on their skin. The proportions of gait phases were compared with , the value of which is about 1.6180. The ratio between the entire gait cycle and stance phase resulted in 1.620 ± 0.058, that between stance and the swing phase was 1.629 ± 0.173, and that between swing and the double support phase was 1.684 ± 0.357. All these ratios did not differ significantly from each other (, , repeated measure analysis of variance or from (, resp., t-tests. The repetitive gait phases of physiological walking were found in turn in repetitive proportions with each other, revealing an intrinsic harmonic structure. Harmony could be the key for facilitating the control of repetitive walking. Harmony is a powerful unifying factor between seemingly disparate fields of nature, including human gait.

  2. Iconicity in Discourse: The Case of Repetition in Japanese.

    Science.gov (United States)

    Ishikawa, Minako

    This analysis of repeated utterances in Japanese conversational discourse focuses on repetition as an expression of iconicity. In the analysis of a 30-minute conversation among 4 Japanese speakers, the iconic meanings expressed by both reduplication and conversational repetition are highlighted. The iconicity characteristic of conversational data…

  3. Evidence-Based Behavioral Interventions for Repetitive Behaviors in Autism

    Science.gov (United States)

    Boyd, Brian A.; McDonough, Stephen G.; Bodfish, James W.

    2012-01-01

    Restricted and repetitive behaviors (RRBs) are a core symptom of autism spectrum disorders (ASD). There has been an increased research emphasis on repetitive behaviors; however, this research primarily has focused on phenomenology and mechanisms. Thus, the knowledge base on interventions is lagging behind other areas of research. The literature…

  4. Visual attention to advertising : The impact of motivation and repetition

    NARCIS (Netherlands)

    Pieters, RGM; Rosbergen, E; Hartog, M; Corfman, KP; Lynch, JG

    1996-01-01

    Using eye-tracking data, we examine the impact of motivation and repetition on visual attention to advertisements differing in argument quality. Our analyses indicate that repetition leads to an overall decrease in the amount of attention. However, while at first high motivation subjects attend to t

  5. On the Functions of Lexical Repetition in English Texts

    Institute of Scientific and Technical Information of China (English)

    XIAO Fuliang

    2016-01-01

    Lexical repetition, as a cohesive device of an English text, can help make up a cohesive and coherent text. Therefore, in English textual learning, it is helpful for students to know about different patterns and functions of lexical repetition to improve their English level and ability.

  6. Epigenetic Patterns of PTSD: DNA Methylation In Serum of OIF/OEF Servicemembers

    Science.gov (United States)

    2011-01-01

    2116-2120. 54. Fenech M (2001): The role of folic acid and Vitamin B12 in genomic stability of human cells. Mutation Research. 475:57-67. 55...and PTSD, (4, 33-35) to our knowledge , this is the first study to investigate the association between DNA methylation in repetitive elements (LINE-1...simple method for estimating global DNA methylation using bisulfite PCR of repetitive DNA elements. Nucleic Acids Res. 32:e38. 17. Robertson KD (2005

  7. Nonword Repetition and Speech Motor Control in Children

    Directory of Open Access Journals (Sweden)

    Christina Reuterskiöld

    2015-01-01

    Full Text Available This study examined how familiarity of word structures influenced articulatory control in children and adolescents during repetition of real words (RWs and nonwords (NWs. A passive reflective marker system was used to track articulator movement. Measures of accuracy were obtained during repetition of RWs and NWs, and kinematic analysis of movement duration and variability was conducted. Participants showed greater consonant and vowel accuracy during RW than NW repetition. Jaw movement duration was longer in NWs compared to RWs across age groups, and younger children produced utterances with longer jaw movement duration compared to older children. Jaw movement variability was consistently greater during repetition of NWs than RWs in both groups of participants. The results indicate that increases in phonological short-term memory demands affect articulator movement. This effect is most pronounced in younger children. A range of skills may develop during childhood, which supports NW repetition skills.

  8. Soliton repetition rate in a silicon-nitride microresonator

    CERN Document Server

    Bao, Chengying; Wang, Cong; Jaramillo-Villegas, Jose A; Leaird, Daniel E; Qi, Minghao; Weiner, Andrew M

    2016-01-01

    The repetition rate of a Kerr comb comprising a single soliton in an anomalous dispersion silicon nitride microcavity is measured as a function of pump frequency tuning. The contributions from the Raman soliton self-frequency shift (SSFS) and from thermal effects are evaluated both experimentally and theoretically; the SSFS is found to dominate the changes in repetition rate. The relationship between the changes in repetition rate and pump frequency detuning is found to be independent of the nonlinearity coefficient and dispersion of the cavity. Modeling of the repetition rate change by using the generalized Lugiato-Lefever equation is discussed; the Kerr shock is found to have only a minor effect on repetition rate for cavity solitons with duration down to ~50 fs.

  9. Transgenerational effects of environmental enrichment on repetitive motor behavior development.

    Science.gov (United States)

    Bechard, Allison R; Lewis, Mark H

    2016-07-01

    The favorable consequences of environmental enrichment (EE) on brain and behavior development are well documented. Much less is known, however, about transgenerational benefits of EE on non-enriched offspring. We explored whether transgenerational effects of EE might extend to the development of repetitive motor behaviors in deer mice. Repetitive motor behaviors are invariant patterns of movement that, across species, can be reduced by EE. We found that EE not only attenuated the development of repetitive behavior in dams, but also in their non-enriched offspring. Moreover, maternal behavior did not seem to mediate the transgenerational effect we found, although repetitive behavior was affected by reproductive experience. These data support a beneficial transgenerational effect of EE on repetitive behavior development and suggest a novel benefit of reproductive experience.

  10. Soliton repetition rate in a silicon-nitride microresonator.

    Science.gov (United States)

    Bao, Chengying; Xuan, Yi; Wang, Cong; Jaramillo-Villegas, Jose A; Leaird, Daniel E; Qi, Minghao; Weiner, Andrew M

    2017-02-15

    The repetition rate of a Kerr comb composed of a single soliton in an anomalous group velocity dispersion silicon-nitride microcavity is measured as a function of pump frequency. By comparing operation in the soliton and non-soliton states, the contributions from the Raman soliton self-frequency shift (SSFS) and the thermal effects are evaluated; the SSFS is found to dominate the changes in the repetition rate, similar to silica cavities. The relationship between the changes in the repetition rate and the pump frequency detuning is found to be independent of the nonlinearity coefficient and dispersion of the cavity. Modeling of the repetition rate change by using the generalized Lugiato-Lefever equation is discussed; the Kerr shock is found to have only a minor effect on repetition rate for cavity solitons with duration down to ∼50  fs.

  11. Self-controlled KR schedules: does repetition order matter?

    Science.gov (United States)

    Patterson, Jae T; Carter, Michael J; Hansen, Steve

    2013-08-01

    The impact of an experimenter-defined repetition schedule on the utility of a self-controlled KR context during motor skill acquisition was examined. Participants were required to learn three novel spatial-temporal tasks in either a random or blocked repetition schedule with or without the opportunity to control their KR. Results from the retention period showed that participants provided control over their KR schedule in a random repetition schedule demonstrated superior learning. However, performance measures from the transfer test showed that, independent of repetition schedule, learners provided the opportunity to control their KR schedule demonstrated superior transfer performance compared to their yoked counterparts. The dissociated impact of repetition schedule and self-controlled KR schedules on retention and transfer is discussed.

  12. Impaired speech repetition and left parietal lobe damage.

    Science.gov (United States)

    Fridriksson, Julius; Kjartansson, Olafur; Morgan, Paul S; Hjaltason, Haukur; Magnusdottir, Sigridur; Bonilha, Leonardo; Rorden, Christopher

    2010-08-18

    Patients with left hemisphere damage and concomitant aphasia usually have difficulty repeating others' speech. Although impaired speech repetition, the primary symptom of conduction aphasia, has been associated with involvement of the left arcuate fasciculus, its specific lesion correlate remains elusive. This research examined speech repetition among 45 stroke patients who underwent aphasia testing and MRI examination. Based on lesion-behavior mapping, the primary structural damage most closely associated with impaired speech repetition was found in the posterior portion of the left arcuate fasciculus. However, perfusion-weighted MRI revealed that tissue dysfunction, in the form of either frank damage or hypoperfusion, to the left inferior parietal lobe, rather than the underlying white matter, was associated with impaired speech repetition. This latter result suggests that integrity of the left inferior parietal lobe is important for speech repetition and, as importantly, highlights the importance of examining cerebral perfusion for the purpose of lesion-behavior mapping in acute stroke.

  13. Repetition and Emotive Communication in Music Versus Speech

    Directory of Open Access Journals (Sweden)

    Elizabeth Hellmuth eMargulis

    2013-04-01

    Full Text Available Music and speech are often placed alongside one another as comparative cases. Their relative overlaps and disassociations have been well explored (e.g. Patel, 2010. But one key attribute distinguishing these two domains has often been overlooked: the greater preponderance of repetition in music in comparison to speech. Recent fMRI studies have shown that familiarity – achieved through repetition – is a critical component of emotional engagement with music (Pereira et al., 2011. If repetition is fundamental to emotional responses to music, and repetition is a key distinguisher between the domains of music and speech, then close examination of the phenomenon of repetition might help clarify the ways that music elicits emotion differently than speech.

  14. Physical Characteristics Underpinning Repetitive Lunging in Fencing.

    Science.gov (United States)

    Turner, Anthony N; Marshall, Geoff; Phillips, James; Noto, Angelo; Buttigieg, Conor; Chavda, Shyam; Downing, William; Atlay, Nathan; Dimitriou, Lygeri; Kilduff, Laim

    2016-11-01

    Turner, AN, Marshall, G, Phillips, J, Noto, A, Buttigieg, C, Chavda, S, Downing, W, Atlay, N, Dimitriou, L, and Kilduff, L. Physical characteristics underpinning repetitive lunging in fencing. J Strength Cond Res 30(11): 3134-3139, 2016-Given the repetitive demand to execute lunging and changes in direction within fencing, the ability to sustain these at maximal capacity is fundamental to performance. The aim of this study was threefold. First, to provide normative values for this variable referred to as repeat lunge ability (RLA) and second to identify the physical characteristics that underpin it. Third, was to establish if a cause and effect relationship existed by training the associated characteristics. Assessment of lower-body power, reactive strength, speed, change of direction speed (CODS), and a sport-specific RLA were conducted on senior and junior elite male fencers (n = 36). Fencers were on average (±SD) 18.9 ± 3.2 years of age, 174.35 ± 10.42 cm tall, 70.67 ± 7.35 kg in mass, and 8.5 ± 4.2 years fencing experience. The RLA test had average work times of 16.03 ± 1.40 seconds and demonstrated "large" to "very large" associations with all tested variables, but in particular CODS (r = 0.70) and standing broad jump (SBJ; r = -0.68). Through linear regression analysis, these also provided a 2-predictor model accounting for 61% of the common variance associated with RLA. A cause and effect relationship with SBJ and CODS was confirmed by the training group, where RLA performance in these fencers improved from 15.80 ± 1.07 to 14.90 ± 0.86 seconds, with the magnitude of change reported as "moderate" (effect size (ES) = 0.93). Concurrent improvements were also noted in both SBJ (216.86 ± 17.15 vs. 221.71 ± 17.59 cm) and CODS (4.44 ± 0.29 vs. 4.31 ± 0.09 seconds) and while differences were only significant in SBJ, magnitudes of change were classed as "small" (ES = 0.28) and "moderate" (ES = 0.61), respectively. In conclusion, to improve RLA strength

  15. Tandem repeat DNA localizing on the proximal DAPI bands of chromosomes in Larix, Pinaceae.

    Science.gov (United States)

    Hizume, Masahiro; Shibata, Fukashi; Matsumoto, Ayako; Maruyama, Yukie; Hayashi, Eiji; Kondo, Teiji; Kondo, Katsuhiko; Zhang, Shozo; Hong, Deyuan

    2002-08-01

    Repetitive DNA was cloned from HindIII-digested genomic DNA of Larix leptolepis. The repetitive DNA was about 170 bp long, had an AT content of 67%, and was organized tandemly in the genome. Using fluorescence in situ hybridization and subsequent DAPI banding, the repetitive DNA was localized in DAPI bands at the proximal region of one arm of chromosomes in L. leptolepis and Larix chinensis. Southern blot hybridization to genomic DNA of seven species and five varieties probed with cloned repetitive DNA showed that the repetitive DNA family was present in a tandem organization in genomes of all Larix taxa examined. In addition to the 170-bp sequence, a 220-bp sequence belonging to the same DNA family was also present in 10 taxa. The 220-bp repeat unit was a partial duplication of the 170-bp repeat unit. The 220-bp repeat unit was more abundant in L. chinensis and Larix potaninii var. macrocarpa than in other taxa. The repetitive DNA composed 2.0-3.4% of the genome in most taxa and 0.3 and 0.5% of the genome in L. chinensis and L. potaninii var. macrocarpa, respectively. The unique distribution of the 220-bp repeat unit in Larix indicates the close relationship of these two species. In the family Pinaceae, the LPD (Larix proximal DAPI band specific repeat sequence family) family sequence is widely distributed, but their amount is very small except in the genus Larix. The abundant LPD family in Larix will occur after its speciation.

  16. Generation of low-timing-jitter femtosecond pulse trains with 2 GHz repetition rate via external repetition rate multiplication.

    Science.gov (United States)

    Chen, Jian; Sickler, Jason W; Fendel, Peter; Ippen, Erich P; Kärtner, Franz X; Wilken, Tobias; Holzwarth, Ronald; Hänsch, Theodor W

    2008-05-01

    Generation of low-timing-jitter 150 fs pulse trains at 1560 nm with 2 GHz repetition rate is demonstrated by locking a 200 MHz fundamental polarization additive-pulse mode-locked erbium fiber laser to high-finesse external Fabry-Perot cavities. The timing jitter and relative intensity noise of the repetition-rate multiplied pulse train are investigated.

  17. [Rehabilitation Using Repetitive Transcranial Magnetic Stimulation].

    Science.gov (United States)

    Takeuchi, Naoyuki; Izumi, Shin-Ichi

    2017-03-01

    Various novel stroke rehabilitative methods have been developed based on findings in basic science and clinical research. Recently, many reports have shown that repetitive transcranial magnetic stimulation (rTMS) improves function in stroke patients by altering the excitability of the human cortex. The interhemispheric competition model proposes that deficits in stroke patients are due to reduced output from the affected hemisphere and excessive interhemispheric inhibition from the unaffected hemisphere to the affected hemisphere. The interhemispheric competition model indicates that improvement in deficits can be achieved either by increasing the excitability of the affected hemisphere using excitatory rTMS or by decreasing the excitability of the unaffected hemisphere using inhibitory rTMS. Recovery after stroke is related to neural plasticity, which involves developing new neural connections, acquiring new functions, and compensating for impairments. Artificially modulating the neural network by rTMS may induce a more suitable environment for use-dependent plasticity and also may interfere with maladaptive neural activation, which weakens function and limits recovery. There is potential, therefore, for rTMS to be used as an adjuvant therapy for developed neurorehabilitation techniques in stroke patients.

  18. SI Engine with repetitive NS spark plug

    Science.gov (United States)

    Pancheshniy, Sergey; Nikipelov, Andrey; Anokhin, Eugeny; Starikovskiy, Andrey; Laplase Team; Mipt Team; Pu Team

    2013-09-01

    Now de-facto the only technology for fuel-air mixtures ignition in IC engines exists. It is a spark discharge of millisecond duration in a short discharge gap. The reason for such a small variety of methods of ignition initiation is very specific conditions of the engine operation. First, it is very high-pressure of fuel-air mixture - from 5-7 atmospheres in old-type engines and up to 40-50 atmospheres on the operating mode of HCCI. Second, it is a very wide range of variation of the oxidizer/fuel ratio in the mixture - from almost stoichiometric (0.8-0.9) at full load to very lean (φ = 0.3-0.5) mixtures at idle and/or economical cruising mode. Third, the high velocity of the gas in the combustion chamber (up to 30-50 m/s) resulting in a rapid compression of swirling inlet flow. The paper presents the results of tests of distributed spark ignition system powered by repetitive pulse nanosecond discharge. Dynamic pressure measurements show the increased pressure and frequency stability for nanosecond excitation in comparison with the standard spark plug. Excitation by single nanosecond high-voltage pulse and short train of pulses was examined. In all regimes the nanosecond pulsed excitation demonstrate a better performance.

  19. Repetitive transcranial magnetic stimulation and drug addiction.

    Science.gov (United States)

    Barr, Mera S; Farzan, Faranak; Wing, Victoria C; George, Tony P; Fitzgerald, Paul B; Daskalakis, Zafiris J

    2011-10-01

    Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive brain stimulation technique that is now being tested for its ability to treat addiction. This review discusses current research approaches and results of studies which measured the therapeutic use of rTMS to treat tobacco, alcohol and illicit drug addiction. The research in this area is limited and therefore all studies evaluating the therapeutic use of rTMS in tobacco, alcohol or illicit drug addiction were retained including case studies through NCBI PubMed ( http://www.ncbi.nlm.nih.gov ) and manual searches. A total of eight studies were identified that examined the ability of rTMS to treat tobacco, alcohol and cocaine addiction. The results of this review indicate that rTMS is effective in reducing the level of cravings for smoking, alcohol, and cocaine when applied at high frequencies to the dorsolateral prefrontal cortex (DLPFC). Furthermore, these studies suggest that repeated sessions of high frequency rTMS over the DLPFC may be most effective in reducing the level of smoking and alcohol consumption. Although work in this area is limited, this review indicates that rTMS is a promising modality for treating drug addiction.

  20. Development of a repetitive compact torus injector

    Science.gov (United States)

    Onchi, Takumi; McColl, David; Dreval, Mykola; Rohollahi, Akbar; Xiao, Chijin; Hirose, Akira; Zushi, Hideki

    2013-10-01

    A system for Repetitive Compact Torus Injection (RCTI) has been developed at the University of Saskatchewan. CTI is a promising fuelling technology to directly fuel the core region of tokamak reactors. In addition to fuelling, CTI has also the potential for (a) optimization of density profile and thus bootstrap current and (b) momentum injection. For steady-state reactor operation, RCTI is necessary. The approach to RCTI is to charge a storage capacitor bank with a large capacitance and quickly charge the CT capacitor bank through a stack of integrated-gate bipolar transistors (IGBTs). When the CT bank is fully charged, the IGBT stack will be turned off to isolate banks, and CT formation/acceleration sequence will start. After formation of each CT, the fast bank will be replenished and a new CT will be formed and accelerated. Circuits for the formation and the acceleration in University of Saskatchewan CT Injector (USCTI) have been modified. Three CT shots at 10 Hz or eight shots at 1.7 Hz have been achieved. This work has been sponsored by the CRC and NSERC, Canada.

  1. Differential effects of high-temperature stress on nuclear topology and transcription of repetitive noncoding and coding rye sequences.

    Science.gov (United States)

    Tomás, D; Brazão, J; Viegas, W; Silva, M

    2013-01-01

    The plant stress response has been extensively characterized at the biochemical and physiological levels. However, knowledge concerning repetitive sequence genome fraction modulation during extreme temperature conditions is scarce. We studied high-temperature effects on subtelomeric repetitive sequences (pSc200) and 45S rDNA in rye seedlings submitted to 40°C during 4 h. Chromatin organization patterns were evaluated through fluorescent in situ hybridization and transcription levels were assessed using quantitative real-time PCR. Additionally, the nucleolar dynamics were evaluated through fibrillarin immunodetection in interphase nuclei. The results obtained clearly demonstrated that the pSc200 sequence organization is not affected by high-temperature stress (HTS) and proved for the first time that this noncoding subtelomeric sequence is stably transcribed. Conversely, it was demonstrated that HTS treatment induces marked rDNA chromatin decondensation along with nucleolar enlargement and a significant increase in ribosomal gene transcription. The role of noncoding and coding repetitive rye sequences in the plant stress response that are suggested by their clearly distinct behaviors is discussed. While the heterochromatic conformation of pSc200 sequences seems to be involved in the stabilization of the interphase chromatin architecture under stress conditions, the dynamic modulation of nucleolar and rDNA topology and transcription suggest their role in plant stress response pathways.

  2. Repetitive energy transfer from an inductive energy store

    Energy Technology Data Exchange (ETDEWEB)

    Honig, E.M.

    1984-01-01

    The theoretical and experimental results of a research program aimed at finding practical ways to transfer energy repetitively from an inductive energy store to various loads are discussed. The objectives were to investigate and develop the high power opening switches and transfer circuits needed to enable high-repetition-rate operation of such systems, including a feasibility demonstration at a current level near 10 kA and a pulse repetition rate of 1-10 kpps with a 1-ohm load. The requirements of nonlinear, time-varying loads, such as the railgun electromagnetic launcher, were also addressed. Energy storage capability is needed for proper power conditioning in systems where the duty factor of the output pulse train is low. Inductive energy storage is attractive because it has both a high energy storage density and a fast discharge capability. By producing a pulse train with a peak power of 75 MW at a pulse repetition rate of 5 kpps in a one-ohm load system, this research program was the first to demonstrate fully-controlled, high-power, high-repetition-rate operation of an inductive energy storage and transfer system with survivable switches. Success was made possible by using triggered vacuum gap switches as repetitive, current-zero opening switches and developing several new repetitive transfer circuits using the counterpulse technique.

  3. Skill learning in mirror reading: how repetition determines acquisition.

    Science.gov (United States)

    Ofen-Noy, N; Dudai, Y; Karni, A

    2003-07-01

    Practice makes perfect, but the role of repetitions in skill learning is not yet fully understood. For example, given a similar number of trials on a given task, it is debated whether repeating and non-repeating items are learned by the same neural process. When one is given training with both types of items--does one learn two separate skills, or only one? Here we show, using a mirror reading task, that practice trials with trial-unique words, and practice trials with repeated words, count towards learning to a different degree. There was no interaction between the time-course of learning repeated and unique words even within the same individuals given mixed training. While repeated words were learned faster than unique words, the repetitions-dependent gains diminished with training beyond a small number of repetitions. Moreover, the gains in performance could not be accounted for solely by the number of repetitions, as assumed by power-law models of learning; rather, the passage of time was a critical factor. Finally, our results suggest that although both repeated and new words were learned by both declarative and procedural memory mechanisms, even a single repetition of specific words could lead to the establishment of a selective differential representation in memory. The results are compatible with the notion of a repetition-sensitive process, triggered by specific repeating events. This 'repetition counter' may be a critical trigger for the effective formation of procedural as well as some type of declarative memory.

  4. Repetition-based Interactive Facade Modeling

    KAUST Repository

    AlHalawani, Sawsan

    2012-07-01

    Modeling and reconstruction of urban environments has gained researchers attention throughout the past few years. It spreads in a variety of directions across multiple disciplines such as image processing, computer graphics and computer vision as well as in architecture, geoscience and remote sensing. Having a virtual world of our real cities is very attractive in various directions such as entertainment, engineering, governments among many others. In this thesis, we address the problem of processing a single fa cade image to acquire useful information that can be utilized to manipulate the fa cade and generate variations of fa cade images which can be later used for buildings\\' texturing. Typical fa cade structures exhibit a rectilinear distribution where in windows and other elements are organized in a grid of horizontal and vertical repetitions of similar patterns. In the firt part of this thesis, we propose an efficient algorithm that exploits information obtained from a single image to identify the distribution grid of the dominant elements i.e. windows. This detection method is initially assisted with the user marking the dominant window followed by an automatic process for identifying its repeated instances which are used to define the structure grid. Given the distribution grid, we allow the user to interactively manipulate the fa cade by adding, deleting, resizing or repositioning the windows in order to generate new fa cade structures. Having the utility for the interactive fa cade is very valuable to create fa cade variations and generate new textures for building models. Ultimately, there is a wide range of interesting possibilities of interactions to be explored.

  5. Understanding communicative actions: a repetitive TMS study.

    Science.gov (United States)

    Stolk, Arjen; Noordzij, Matthijs L; Volman, Inge; Verhagen, Lennart; Overeem, Sebastiaan; van Elswijk, Gijs; Bloem, Bas; Hagoort, Peter; Toni, Ivan

    2014-02-01

    Despite the ambiguity inherent in human communication, people are remarkably efficient in establishing mutual understanding. Studying how people communicate in novel settings provides a window into the mechanisms supporting the human competence to rapidly generate and understand novel shared symbols, a fundamental property of human communication. Previous work indicates that the right posterior superior temporal sulcus (pSTS) is involved when people understand the intended meaning of novel communicative actions. Here, we set out to test whether normal functioning of this cerebral structure is required for understanding novel communicative actions using inhibitory low-frequency repetitive transcranial magnetic stimulation (rTMS). A factorial experimental design contrasted two tightly matched stimulation sites (right pSTS vs left MT+, i.e., a contiguous homotopic task-relevant region) and tasks (a communicative task vs a visual tracking task that used the same sequences of stimuli). Overall task performance was not affected by rTMS, whereas changes in task performance over time were disrupted according to TMS site and task combinations. Namely, rTMS over pSTS led to a diminished ability to improve action understanding on the basis of recent communicative history, while rTMS over MT+ perturbed improvement in visual tracking over trials. These findings qualify the contributions of the right pSTS to human communicative abilities, showing that this region might be necessary for incorporating previous knowledge, accumulated during interactions with a communicative partner, to constrain the inferential process that leads to action understanding. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Epithelial topography for repetitive tooth formation

    Directory of Open Access Journals (Sweden)

    Marcia Gaete

    2015-12-01

    Full Text Available During the formation of repetitive ectodermally derived organs such as mammary glands, lateral line and teeth, the tissue primordium iteratively initiates new structures. In the case of successional molar development, new teeth appear sequentially in the posterior region of the jaw from Sox2+ cells in association with the posterior aspect of a pre-existing tooth. The sequence of molar development is well known, however, the epithelial topography involved in the formation of a new tooth is unclear. Here, we have examined the morphology of the molar dental epithelium and its development at different stages in the mouse in vivo and in molar explants. Using regional lineage tracing we show that within the posterior tail of the first molar the primordium for the second and third molar are organized in a row, with the tail remaining in connection with the surface, where a furrow is observed. The morphology and Sox2 expression of the tail retains characteristics reminiscent of the earlier stages of tooth development, such that position along the A-P axes of the tail correlates with different temporal stages. Sox9, a stem/progenitor cell marker in other organs, is expressed mainly in the suprabasal epithelium complementary with Sox2 expression. This Sox2 and Sox9 expressing molar tail contains actively proliferating cells with mitosis following an apico-basal direction. Snail2, a transcription factor implicated in cell migration, is expressed at high levels in the tip of the molar tail while E-cadherin and laminin are decreased. In conclusion, our studies propose a model in which the epithelium of the molar tail can grow by posterior movement of epithelial cells followed by infolding and stratification involving a population of Sox2+/Sox9+ cells.

  7. Repetitive transcranial magnetic stimulation in psychiatry

    Directory of Open Access Journals (Sweden)

    Biswa Ranjan Mishra

    2011-01-01

    Full Text Available Repetitive transcranial magnetic stimulation (rTMS is a non-invasive and relatively painless tool that has been used to study various cognitive functions as well as to understand the brain-behavior relationship in normal individuals as well as in those with various neuropsychiatric disorders. It has also been used as a therapeutic tool in various neuropsychiatric disorders because of its ability to specifically modulate distinct brain areas. Studies have shown that repeated stimulation at low frequency produces long-lasting inhibition, which is called as long-term depression, whereas repeated high-frequency stimulation can produce excitation through long-term potentiation. This paper reviews the current status of rTMS as an investigative and therapeutic modality in various neuropsychiatric disorders. It has been used to study the cortical and subcortical functions, neural plasticity and brain mapping in normal individuals and in various neuropsychiatric disorders. rTMS has been most promising in the treatment of depression, with an overall milder adverse effect profile compared with electroconvulsive therapy. In other neuropsychiatric disorders such as schizophrenia, mania, epilepsy and substance abuse, it has been found to be useful, although further studies are required to establish therapeutic efficacy. It appears to be ineffective in the treatment of obsessive compulsive disorder. There is a paucity of studies of efficacy and safety of rTMS in pediatric and geriatric population. Although it appears safe, further research is required to optimize its efficacy and reduce the side-effects. Magnetic seizure therapy, which involves producing seizures akin to electroconvulsive therapy, appears to be of comparable efficacy in the treatment of depression with less cognitive adverse effects.

  8. Chromosomal localization of a novel repetitive sequence in the Chenopodium quinoa genome.

    Science.gov (United States)

    Kolano, Bozena; Plucienniczak, Andrzej; Kwasniewski, Miroslaw; Maluszynska, Jolanta

    2008-01-01

    In this study, a novel repetitive sequence pTaq10 was isolated from the Taq I digest of the genomic DNA of the pseudocereal Chenopodium quinoa. Sequence analysis indicated that this 286-bp monomer is not homologous to any known retroelement sequence. FISH and Southern blot analysis showed that this sequence is characterized by an interspersed genomic organization. After FISH, hybridization signals were observed as small dots spread throughout all of the chromosomes. pTaq hybridization signals were excluded from 45S rRNA gene loci, but they partly overlapped with 5S rDNA loci. pTaq10 is not a species-specific sequence, as it was also detected in C. berlandieri.

  9. Clinical application of repetitive transcranial magnetic stimulation in stroke rehabilitation☆

    Science.gov (United States)

    Shin, Joonho; Yang, EunJoo; Cho, KyeHee; Barcenas, Carmelo L; Kim, Woo Jin; Min, Yusun; Paik, Nam-Jong

    2012-01-01

    Proper stimulation to affected cerebral hemisphere would promote the functional recovery of patients with stroke. Effects of repetitive transcranial magnetic stimulation on cortical excitability can be can be altered by the stimulation frequency, intensity and duration. There has been no consistent recognition regarding the best stimulation frequency and intensity. This study reviews the intervention effects of repetitive transcranial stimulation on motor impairment, dysphagia, visuospatial neglect and aphasia, and summarizes the stimulation frequency, intensity and area for repetitive transcranial magnetic stimulation to yield the best therapeutic effects. PMID:25745455

  10. Clinical application of repetitive transcranial magnetic stimulation in stroke rehabilitation

    Institute of Scientific and Technical Information of China (English)

    Joonho Shin; EunJoo Yang; KyeHee Cho; Carmelo L Barcenas; Woo Jin Kim; Yusun Min; Nam-Jong Paik

    2012-01-01

    Proper stimulation to affected cerebral hemisphere would promote the functional recovery of patients with stroke. Effects of repetitive transcranial magnetic stimulation on cortical excitability can be can be altered by the stimulation frequency, intensity and duration. There has been no consistent recognition regarding the best stimulation frequency and intensity. This study reviews the intervention effects of repetitive transcranial stimulation on motor impairment, dysphagia, visuospatial neglect and aphasia, and summarizes the stimulation frequency, intensity and area for repetitive transcranial magnetic stimulation to yield the best therapeutic effects.

  11. Chromosomal organization of repetitive DNAs in Hordeum bogdanii and H. brevisubulatum (Poaceae

    Directory of Open Access Journals (Sweden)

    Quanwen Dou

    2016-10-01

    Full Text Available Molecular karyotypes of H. bogdanii Wilensky, 1918 (2n = 14, and H. brevisubulatum Link, 1844 ssp. brevisubulatum (2n = 28, were characterized by physical mapping of several repetitive sequences. A total of 18 repeats, including all possible di- or trinucleotide SSR (simple sequence repeat motifs and satellite DNAs, such as pAs1, 5S rDNA, 45S rDNA, and pSc119.2, were used as probes for fluorescence in situ hybridization on root-tip metaphase chromosomes. Except for the SSR motifs AG, AT and GC, all the repeats we examined produced detectable hybridization signals on chromosomes of both species. A detailed molecular karyotype of the I genome of H. bogdanii is described for the first time, and each repetitive sequence is physically mapped. A high degree of chromosome variation, including aneuploidy and structural changes, was observed in H. brevisubulatum. Although the distribution of repeats in the chromosomes of H. brevisubulatum is different from that of H. bogdanii, similar patterns between the two species imply that the autopolyploid origin of H. brevisubulatum is from a Hordeum species with an I genome. A comparison of the I genome and the other Hordeum genomes, H, Xa and Xu, shows that colocalization of motifs AAC, ACT and CAT and colocalization of motifs AAG and AGG are characteristic of the I genome. In addition, we discuss the evolutionary significance of repeats in the genome during genome differentiation.

  12. Screening and detection of repetitive extragenic palindromic sequences with TLR9 agonistic activity from Brucella abortus DNA%活化TLR9的牛种布氏菌基因外重复回文序列筛选及活性检测

    Institute of Scientific and Technical Information of China (English)

    张雅娴; 白丽云; 王占黎; 王英; 于慧

    2016-01-01

    目的 筛选具有活化Toll样受体9(TLR9)的牛种布氏菌基因外重复回文序列(Repetitive Extragenic Palin-drome Squence,REPs)并检测其活性,为布氏菌病的治疗提供新思路.方法 基于Brucella abortus A13334基因组序列,利用生物信息学技术识别其REPs后,合成序列.将合成的天然骨架的脱氧寡核苷酸(ODNs)转染小鼠单核巨噬细胞株RAW264.7,以ELISA检测IFN-α的分泌水平.采用TLR9-siRNA沉默RAW264.7中的TLR9,将上述诱导IFN-α分泌增加的阳性ODN序列转染RAW264.7,ELISA方法检测IFN-α的分泌变化.结果 筛选出1857条牛种布氏菌REPs,选择2级茎环结构较好的5条ODNs序列进行合成,ELISA方法检测显示ODNs M4、M5介导IFN-α分泌量显著高于阴性对照(P<0.05),且阳性ODN M5所介导的IFN-α分泌可以被TLR9-siRNA显著抑制.结论 布氏菌基因组中存在可以活化TLR9信号通路的REPs,此结果有助于对布氏菌致病和免疫机制的认识.

  13. Shortening of subjective visual intervals followed by repetitive stimulation.

    Directory of Open Access Journals (Sweden)

    Fuminori Ono

    Full Text Available Our previous research demonstrated that repetitive tone stimulation shortened the perceived duration of the preceding auditory time interval. In this study, we examined whether repetitive visual stimulation influences the perception of preceding visual time intervals. Results showed that a time interval followed by a high-frequency visual flicker was perceived as shorter than that followed by a low-frequency visual flicker. The perceived duration decreased as the frequency of the visual flicker increased. The visual flicker presented in one hemifield shortened the apparent time interval in the other hemifield. A final experiment showed that repetitive tone stimulation also shortened the perceived duration of preceding visual time intervals. We concluded that visual flicker shortened the perceived duration of preceding visual time intervals in the same way as repetitive auditory stimulation shortened the subjective duration of preceding tones.

  14. The relationship between task repetition and language proficiency

    Directory of Open Access Journals (Sweden)

    Ahmad Mojavezi

    2014-01-01

    Full Text Available Task repetition is now considered as an important task-based implementation variable which can affect complexity, accuracy, and fluency of L2 speech. However, in order to move towards theorizing the role of task repetition in second language acquisition, it is necessary that individual variables be taken into account. The present study aimed to investigate the way task repetition correlates with language proficiency and the differential effects that task repetition might have on the complexity, accuracy, and fluency of L2 learners with different levels of proficiency. Fifty language learners of different levels of proficiency, selected from two different language centers, participated in this study. They were asked to perform an oral narrative task twice with a one-week interval. Results revealed that, compared to the participants with lower L2 proficiency, participants with higher levels of L2 proficiency produced more complex, accurate, and fluent speech on the second encounter with the same task.

  15. The repetition effect in building and construction works

    DEFF Research Database (Denmark)

    Gottlieb, Stefan Christoffer; Haugbølle, Kim

    are then applied on the Public Transport Authorities' main account structure of units and costs, and a method for assessing the possibilities of achieving effects of repetition for each account is described. Finally, the report summarises the core conditions necessary to take into consideration in relation......This report summarises the results from the work undertaken for the Public Transport Authority on the effect of learning and repetition in building and construction works. The results are applied by the Public Transport Authority in a new budgeting model, while the agency investigates...... the establishment of a new railway between Copenhagen and Ringsted. Drawing on an extensive literature review, the effect of repetition is determined to be in the range of 6-12 %. Further, the report identifies a series of factors affecting the possibilities of achieving effects of repetition. These factors...

  16. Neural dynamics during repetitive visual stimulation

    Science.gov (United States)

    Tsoneva, Tsvetomira; Garcia-Molina, Gary; Desain, Peter

    2015-12-01

    Objective. Steady-state visual evoked potentials (SSVEPs), the brain responses to repetitive visual stimulation (RVS), are widely utilized in neuroscience. Their high signal-to-noise ratio and ability to entrain oscillatory brain activity are beneficial for their applications in brain-computer interfaces, investigation of neural processes underlying brain rhythmic activity (steady-state topography) and probing the causal role of brain rhythms in cognition and emotion. This paper aims at analyzing the space and time EEG dynamics in response to RVS at the frequency of stimulation and ongoing rhythms in the delta, theta, alpha, beta, and gamma bands. Approach.We used electroencephalography (EEG) to study the oscillatory brain dynamics during RVS at 10 frequencies in the gamma band (40-60 Hz). We collected an extensive EEG data set from 32 participants and analyzed the RVS evoked and induced responses in the time-frequency domain. Main results. Stable SSVEP over parieto-occipital sites was observed at each of the fundamental frequencies and their harmonics and sub-harmonics. Both the strength and the spatial propagation of the SSVEP response seem sensitive to stimulus frequency. The SSVEP was more localized around the parieto-occipital sites for higher frequencies (>54 Hz) and spread to fronto-central locations for lower frequencies. We observed a strong negative correlation between stimulation frequency and relative power change at that frequency, the first harmonic and the sub-harmonic components over occipital sites. Interestingly, over parietal sites for sub-harmonics a positive correlation of relative power change and stimulation frequency was found. A number of distinct patterns in delta (1-4 Hz), theta (4-8 Hz), alpha (8-12 Hz) and beta (15-30 Hz) bands were also observed. The transient response, from 0 to about 300 ms after stimulation onset, was accompanied by increase in delta and theta power over fronto-central and occipital sites, which returned to baseline

  17. Chromosomal Mapping of Repetitive DNAs in the Grasshopper Abracris flavolineata Reveal Possible Ancestry of the B Chromosome and H3 Histone Spreading.

    Directory of Open Access Journals (Sweden)

    Danilo Bueno

    Full Text Available Supernumerary chromosomes (B chromosomes occur in approximately 15% of eukaryote species. Although these chromosomes have been extensively studied, knowledge concerning their specific molecular composition is lacking in most cases. The accumulation of repetitive DNAs is one remarkable characteristic of B chromosomes, and the occurrence of distinct types of multigene families, satellite DNAs and some transposable elements have been reported. Here, we describe the organization of repetitive DNAs in the A complement and B chromosome system in the grasshopper species Abracris flavolineata using classical cytogenetic techniques and FISH analysis using probes for five multigene families, telomeric repeats and repetitive C0t-1 DNA fractions. The 18S rRNA and H3 histone multigene families are highly variable and well distributed in A. flavolineata chromosomes, which contrasts with the conservation of U snRNA genes and less variable distribution of 5S rDNA sequences. The H3 histone gene was an extensively distributed with clusters occurring in all chromosomes. Repetitive DNAs were concentrated in C-positive regions, including the pericentromeric region and small chromosomal arms, with some occurrence in C-negative regions, but abundance was low in the B chromosome. Finally, the first demonstration of the U2 snRNA gene in B chromosomes in A. flavolineata may shed light on its possible origin. These results provide new information regarding chromosomal variability for repetitive DNAs in grasshoppers and the specific molecular composition of B chromosomes.

  18. Autism and exergaming: effects on repetitive behaviors and cognition

    OpenAIRE

    Anderson-Hanley C; Tureck K; Schneiderman RL

    2011-01-01

    Cay Anderson-Hanley, Kimberly Tureck, Robyn L Schneiderman Department of Psychology, Union College, Schenectady, NY, USA Abstract: Autism is a neurodevelopmental disorder that leads to impairment in social skills and delay in language development, and results in repetitive behaviors and restricted interests that impede academic and social involvement. Physical exercise has been shown to decrease repetitive behaviors in autistic children and improve cognitive function across the life-span. Ex...

  19. Breakdown behavior of electronics at variable pulse repetition rates

    OpenAIRE

    Korte, S.; H. Garbe

    2006-01-01

    The breakdown behavior of electronics exposed to single transient electromagnetic pulses is subject of investigations for several years. State-of-the-art pulse generators additionally provide the possibility to generate pulse sequences with variable pulse repetition rate. In this article the influence of this repetition rate variation on the breakdown behavior of electronic systems is described. For this purpose microcontroller systems are examined during line-led exposure to pulses with repe...

  20. Linear- and Repetitive-Feature Detection Within Remotely Sensed Imagery

    Science.gov (United States)

    2017-04-01

    1.1 Background The Army desires the ability to deliver cargo, equipment, and personnel to harsh locations almost anywhere on the planet . This...because the Hough transform is designed to look for straight linear features, which most real- life fea- tures are not. As mention previously, it is...repetitive features are differentiated based on their appearance in the images of interest; however, real- life repetitive features often corre- spond to

  1. Linear- and Repetitive Feature Detection Within Remotely Sensed Imagery

    Science.gov (United States)

    2017-04-01

    1.1 Background The Army desires the ability to deliver cargo, equipment, and personnel to harsh locations almost anywhere on the planet . This...because the Hough transform is designed to look for straight linear features, which most real- life fea- tures are not. As mention previously, it is...repetitive features are differentiated based on their appearance in the images of interest; however, real- life repetitive features often corre- spond to

  2. Brain Injury Following Repetitive Apnea in Newborn Piglets

    Science.gov (United States)

    Schears, Gregory; Creed, Jennifer; Antoni, Diego; Zaitseva, Tatiana; Greeley, William; Wilson, David F.; Pastuszko, Anna

    Repetitive apnea is associated with a significant increase in extracellular dopamine, generation of free radicals as determined by o-tyrosine formation and increase in Fluoro-Jade staining of degenerating neurons. This increase in extracellular dopamine and of hydroxyl radicals in striatum of newborn brain is likely to be at least partly responsible for the neuronal injury and neurological side effects of repetitive apnea.

  3. Illusory sensation of movement induced by repetitive transcranial magnetic stimulation

    DEFF Research Database (Denmark)

    Christensen, Mark Schram; Lundbye-Jensen, J.; Grey, M.J.;

    2010-01-01

    Human movement sense relies on both somatosensory feedback and on knowledge of the motor commands used to produce the movement. We have induced a movement illusion using repetitive transcranial magnetic stimulation over primary motor cortex and dorsal premotor cortex in the absence of limb moveme...... premotor cortex stimulation was less affected by sensory and motor deprivation than was primary motor cortex stimulation. We propose that repetitive transcranial magnetic stimulation over dorsal premotor cortex produces a corollary discharge that is perceived as movement....

  4. Grade repetition in primary school from teachers’ perspective

    Directory of Open Access Journals (Sweden)

    Malinić Dušica

    2011-01-01

    Full Text Available School underachievement is exhibited gradually, in different forms, while grade repetition figures as one of the most prominent forms of underachievement. In order to observe this phenomenon from different perspectives, we conducted a research aimed at identifying teacher attitudes towards grade repetition and grade repeaters in primary school, based on their perceptions of: (a the cause of grade repetition; (b the responsibility for grade repetition and (c grade repetition as an educational measure. The administered questionnaire was constructed for the purposes of the research, descriptive statistics was used, and data were obtained on the sample of 136 teachers from 31 primary schools from the territory of the City of Belgrade. The results point out to the conclusion that teachers perceive grade repetition as, first and foremost, the consequence of students’ lack of interest in school and learning and undisciplined behavior in class. By treating student underachievement mainly as a consequence of laziness, lack of motivation and insufficient effort, teachers transfer responsibility to others, assessing that the personal degree of responsibility for the underachievement of their students is very low. The responsibility for underachievement is perceived more as a problem of the student, his/her family, peer group, than as the problem of teachers themselves. The concluding part points out to certain teaching procedures and methods that have proved to be useful in the prevention of student underachievement.

  5. Properties of water surface discharge at different pulse repetition rates

    Energy Technology Data Exchange (ETDEWEB)

    Ruma,; Yoshihara, K. [Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555 (Japan); Hosseini, S. H. R., E-mail: hosseini@kumamoto-u.ac.jp; Sakugawa, T.; Akiyama, H. [Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555 (Japan); Institute of Pulsed Power Science, Kumamoto University, Kumamoto 860-8555 (Japan); Akiyama, M. [Department of Electrical and Electronic Engineering, Kagoshima University, Kagoshima 890-0065 (Japan); Lukeš, P. [Institute of Plasma Physics, AS CR, Prague, Prague 18200 (Czech Republic)

    2014-09-28

    The properties of water surface discharge plasma for variety of pulse repetition rates are investigated. A magnetic pulse compression (MPC) pulsed power modulator able to deliver pulse repetition rates up to 1000 Hz, with 0.5 J per pulse energy output at 25 kV, was used as the pulsed power source. Positive pulse with a point-to-plane electrode configuration was used for the experiments. The concentration and production yield of hydrogen peroxide (H₂O₂) were quantitatively measured and orange II organic dye was treated, to evaluate the chemical properties of the discharge reactor. Experimental results show that the physical and chemical properties of water surface discharge are not influenced by pulse repetition rate, very different from those observed for under water discharge. The production yield of H₂O₂ and degradation rate per pulse of the dye did not significantly vary at different pulse repetition rates under a constant discharge mode on water surface. In addition, the solution temperature, pH, and conductivity for both water surface and underwater discharge reactors were measured to compare their plasma properties for different pulse repetition rates. The results confirm that surface discharge can be employed at high pulse repetition rates as a reliable and advantageous method for industrial and environmental decontamination applications.

  6. Polymerase chain reaction-mediated DNA fingerprinting for epidemiological studies on Campylobacter spp

    NARCIS (Netherlands)

    Giesendorf, B A; Goossens, H; Niesters, H G; Van Belkum, A; Koeken, A; Endtz, H P; Stegeman, H; Quint, W G

    1994-01-01

    The applicability of polymerase chain reaction (PCR)-mediated DNA typing, with primers complementary to dispersed repetitive DNA sequences and arbitrarily chosen DNA motifs, to study the epidemiology of campylobacter infection was evaluated. With a single PCR reaction and simple gel electrophoresis,

  7. Polymerase chain reaction-mediated DNA fingerprinting for epidemiological studies on Campylobacter spp

    NARCIS (Netherlands)

    Giesendorf, B A; Goossens, H; Niesters, H G; Van Belkum, A; Koeken, A; Endtz, H P; Stegeman, H; Quint, W G

    The applicability of polymerase chain reaction (PCR)-mediated DNA typing, with primers complementary to dispersed repetitive DNA sequences and arbitrarily chosen DNA motifs, to study the epidemiology of campylobacter infection was evaluated. With a single PCR reaction and simple gel electrophoresis,

  8. Complete nucleotide sequences of two adjacent early vaccinia virus genes located within the inverted terminal repetition.

    Science.gov (United States)

    Venkatesan, S; Gershowitz, A; Moss, B

    1982-11-01

    The proximal part of the 10,000-base pair (bp) inverted terminal repetition of vaccinia virus DNA encodes at least three early mRNAs. A 2,236-bp segment of the repetition was sequenced to characterize two of the genes. This task was facilitated by constructing a series of recombinants containing overlapping deletions; oligonucleotide linkers with synthetic restriction sites provided points for radioactive labeling before sequencing by the chemical degradation method of Maxam and Gilbert (Methods Enzymol. 65:499-560, 1980). The ends of the transcripts were mapped by hybridizing labeled DNA fragments to early viral RNA and resolving nuclease S1-protected fragments in sequencing gels, by sequencing cDNA clones, and from the lengths of the RNAs. The nucleotide sequences for at least 60 bp upstream of both transcriptional initiation sites are more than 80% adenine . thymine rich and contain long runs of adenines and thymines with some homology to procaryotic and eucaryotic consensus sequences. The gene transcribed in the rightward direction encodes an RNA of approximately 530 nucleotides with a single open reading frame of 420 nucleotides. Preceding the first AUG, there is a heptanucleotide that can hybridize to the 3' end of 18S rRNA with only one mismatch. The derived amino acid sequence of the protein indicated a molecular weight of 15,500. The gene transcribed in the leftward direction encodes an RNA 1,000 to 1,100 nucleotides long with an open reading frame of 996 nucleotides and a leader sequence of only 5 to 6 nucleotides. The derived amino acid sequence of this protein indicated a molecular weight of 38,500. The 3' ends of the two transcripts were located within 100 bp of each other. Although there are adenine . thymine-rich clusters near the putative transcriptional termination sites, specific AATAAA polyadenylic acid signal sequences are absent.

  9. Place field repetition and spatial learning in a multicompartment environment.

    Science.gov (United States)

    Grieves, Roddy M; Jenkins, Bryan W; Harland, Bruce C; Wood, Emma R; Dudchenko, Paul A

    2016-01-01

    Recent studies have shown that place cells in the hippocampus possess firing fields that repeat in physically similar, parallel environments. These results imply that it should be difficult for animals to distinguish parallel environments at a behavioral level. To test this, we trained rats on a novel odor-location task in an environment with four parallel compartments which had previously been shown to yield place field repetition. A second group of animals was trained on the same task, but with the compartments arranged in different directions, an arrangement we hypothesised would yield less place field repetition. Learning of the odor-location task in the parallel compartments was significantly impaired relative to learning in the radially arranged compartments. Fewer animals acquired the full discrimination in the parallel compartments compared to those trained in the radial compartments, and the former also required many more sessions to reach criterion compared to the latter. To confirm that the arrangement of compartments yielded differences in place cell repetition, in a separate group of animals we recorded from CA1 place cells in both environments. We found that CA1 place cells exhibited repeated fields across four parallel local compartments, but did not do so when the same compartments were arranged radially. To confirm that the differences in place field repetition across the parallel and radial compartments depended on their angular arrangement, and not incidental differences in access to an extra-maze visual landmark, we repeated the recordings in a second set of rats in the absence of the orientation landmark. We found, once again, that place fields showed repetition in parallel compartments, and did not do so in radially arranged compartments. Thus place field repetition, or lack thereof, in these compartments was not dependent on extra-maze cues. Together, these results imply that place field repetition constrains spatial learning.

  10. A Model of DNA Repeat-Assembled Mitotic Chromosomal Skeleton

    OpenAIRE

    Shao-Jun Tang

    2011-01-01

    Despite intensive investigation for decades, the principle of higher-order organization of mitotic chromosomes is unclear. Here, I describe a novel model that emphasizes a critical role of interactions of homologous DNA repeats (repetitive elements; repetitive sequences) in mitotic chromosome architecture. According to the model, DNA repeats are assembled, via repeat interactions (pairing), into compact core structures that govern the arrangement of chromatins in mitotic chromosomes. Tandem r...

  11. RPERT: Repetitive-Projects Evaluation and Review Technique

    Directory of Open Access Journals (Sweden)

    Remon Fayek Aziz

    2014-03-01

    Full Text Available Estimating expected completion probability of any repetitive construction project with a specified/certain duration including repetitive identical activities by using program evaluation and review technique is the most essential part in construction areas since the activities were had optimistic, most likely and pessimistic durations. This paper focuses on the calculation of expected completion probability of any repetitive construction project within a specified/certain duration (contract duration by using Line Of Balance technique (LOB in case of single or multiple number of crews integrated with Program Evaluation and Review Technique (PERT. Repetitive-Projects Evaluation and Review Technique (RPERT, which is a simplified software, will generate the expected project completion probability of a specified/certain duration (contract duration. RPERT software is designed by java programming code system to provide a number of new and unique capabilities, including: (1 Viewing the expected project completion probability according to a set of specified durations per each identical activity (optimistic time, most likely time, and pessimistic time in the analyzed project; (2 Providing seamless integration with available project time calculations. In order to provide the aforementioned capabilities of RPERT, the system is implemented and developed in four main modules: (1 A user interface module; (2 A database module; (3 A running module; and (4 A processing module. At the end, an illustrative example will be presented to demonstrate and verify the applications of proposed software (RPERT, by using probabilistic calculations for repetitive construction projects.

  12. Autism and exergaming: effects on repetitive behaviors and cognition

    Directory of Open Access Journals (Sweden)

    Anderson-Hanley C

    2011-09-01

    Full Text Available Cay Anderson-Hanley, Kimberly Tureck, Robyn L Schneiderman Department of Psychology, Union College, Schenectady, NY, USA Abstract: Autism is a neurodevelopmental disorder that leads to impairment in social skills and delay in language development, and results in repetitive behaviors and restricted interests that impede academic and social involvement. Physical exercise has been shown to decrease repetitive behaviors in autistic children and improve cognitive function across the life-span. Exergaming combines physical and mental exercise simultaneously by linking physical activity movements to video game control and may yield better compliance with exercise. In this investigation, two pilot studies explored the potential behavioral and cognitive benefits of exergaming. In Pilot I, twelve children with autism spectrum disorders completed a control task and an acute bout of Dance Dance Revolution (DDR; in Pilot II, ten additional youths completed an acute bout of cyber cycling. Repetitive behaviors and executive function were measured before and after each activity. Repetitive behaviors significantly decreased, while performance on Digits Backwards improved following the exergaming conditions compared with the control condition. Additional research is needed to replicate these findings, and to explore the application of exergaming for the management of behavioral disturbance and to increase cognitive control in children on the autism spectrum. Keywords: autism, repetitive behaviors, exergaming, exercise, executive function

  13. Quantifying repetitive speech in autism spectrum disorders and language impairment.

    Science.gov (United States)

    van Santen, Jan P H; Sproat, Richard W; Hill, Alison Presmanes

    2013-10-01

    We report on an automatic technique for quantifying two types of repetitive speech: repetitions of what the child says him/herself (self-repeats) and of what is uttered by an interlocutor (echolalia). We apply this technique to a sample of 111 children between the ages of four and eight: 42 typically developing children (TD), 19 children with specific language impairment (SLI), 25 children with autism spectrum disorders (ASD) plus language impairment (ALI), and 25 children with ASD with normal, non-impaired language (ALN). The results indicate robust differences in echolalia between the TD and ASD groups as a whole (ALN + ALI), and between TD and ALN children. There were no significant differences between ALI and SLI children for echolalia or self-repetitions. The results confirm previous findings that children with ASD repeat the language of others more than other populations of children. On the other hand, self-repetition does not appear to be significantly more frequent in ASD, nor does it matter whether the child's echolalia occurred within one (immediate) or two turns (near-immediate) of the adult's original utterance. Furthermore, non-significant differences between ALN and SLI, between TD and SLI, and between ALI and TD are suggestive that echolalia may not be specific to ALN or to ASD in general. One important innovation of this work is an objective fully automatic technique for assessing the amount of repetition in a transcript of a child's utterances.

  14. ROBUST REPETITIVE CONTROL FOR IMPROVING RATE SMOOTHNESS OF TEST TURNTABLE

    Institute of Scientific and Technical Information of China (English)

    LIUYu; ZENGMing; SUBao-ku

    2005-01-01

    A robust repetitive control scheme is used to improve the rate smoothness of a brushless DC motor (BLDCM) driven test turntable. The method synthesizes variable structure control (VSC) laws and repetitive control (RC) laws in a complementary manner. The VSC strategy can stabilize the system and suppress uncertainties, such as the aperiodic disturbance and noises, while RC strategy can eliminate the periodic rate fluctuation in a steady state. The convergence of the repetitive learning process is also guaranteed by VSC. A general nonlinear system model is discussed. The model can be considered as an extension of BLDCMs. The stability and asymptotic position tracking performance are validated by using Lyapunov functions. Simulation results show the effectiveness of the proposed approach for improving the rate smoothness.

  15. Body-focused repetitive behavior disorders in ICD-11

    Directory of Open Access Journals (Sweden)

    Jon E. Grant

    2014-01-01

    Full Text Available This article addresses the question of how body-focused repetitive behavior disorders (e.g., trichotillomania and skin-picking disorder should be characterized in ICD-11. The article reviews the historical nosology of the two disorders and the current approaches in DSM-5 and ICD-10. Although data are limited and mixed regarding the optimal relationship between body-focused repetitive behavior disorders and nosological categories, these conditions should be included within the obsessive-compulsive and related disorders category, as this is how most clinicians see these behaviors, and as this may optimize clinical utility. The descriptions of these disorders should largely mirror those in DSM-5, given the evidence from recent field surveys. The recommendations regarding ICD-11 and body-focused repetitive behavior disorders should promote the global identification and treatment of these conditions in primary care settings.

  16. Repeated text in unrelated passages: Repetition versus meaning selection effects.

    Science.gov (United States)

    Klin, Celia M; Drumm, April M; Ralano, Angela S

    2009-07-01

    Despite previous findings, Klin, Ralano, and Weingartner (2007) found transfer benefits across unrelated passages. After processing an ambiguous phrase in Story A that was biased toward its sarcastic meaning, readers were more likely to interpret the identical phrase in Story B as sarcastic, even though it contained no disambiguating information. In the present experiments, we found both repetition effects (a benefit for the lexical items) and meaning selection effects (a benefit for the selected meaning of the phrase) with short delays between Stories A and B; with longer delays, only repetition effects were found. Whereas decreasing the elaboration of the phrase eliminated both effects, moving the disambiguating context from before to after the phrase eliminated meaning selection effects only. We conclude that meaning selection effects, which are based on conceptual overlap, are more sensitive to context changes and less robust than repetition effects, which are based on both perceptual and conceptual overlap.

  17. Effects of repetition and temperature on Contingent Electrical Stimulation

    DEFF Research Database (Denmark)

    Castrillon, Eduardo E.; Zhou, Xinwen; Svensson, Peter

    Effects of repetition and temperature on Contingent Electrical Stimulation. E.E. Castrillon W1, 2, Xinwen Zhou 3, P. Svensson1, 2, 4 1 Department of Dentistry and Oral Health, Section of Orofacial Pain and Jaw Function, Aarhus University, Denmark2 Scandinavian Center for Orofacial Neuroscience...... (SCON)3 Department of Dentistry, Beijing Shijitan Hospital, Capital Medical University, Beijing, China. 4 Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden  Background: Contingent electrical stimulation (CES) of the facial skin has been shown to reduce electromyographic (EMG......) activity associated with bruxism. Repetition of the electrical stimulus and skin surface temperature (ST) may affect the perception of CES and possibly also the inhibitory EMG effects.Objectives: To determine the effects of stimulus repetition and skin ST on the perception of CES.  Methods: Healthy...

  18. Restricted Repetitive Sampling in Designing of Control Charts

    Directory of Open Access Journals (Sweden)

    Muhammad Anwar Mughal

    2017-06-01

    Full Text Available In this article a criteria have been defined to classify the existing repetitive sampling into soft, moderate and strict conditions. Behind this division a ratio has been suggested i.e. c2 (constant used in repetitive limits to c1(constant used in control limit in slabs. A restricted criterion has been devised on the existing repetitive sampling. By embedding the proposed schematic in the control chart it becomes highly efficient in detecting the shifts quite earlier as well as it detects even smaller shifts at smaller ARLs. To facilitate the user for best choice the restricted criterion has further categorized to softly restricted, moderately restricted and strictly restricted. The restricted conditions are dependent on value of restriction parameter ’m’ varies 2 to 6. The application of proposed scheme on selected cases is given in tables which are self explanatory.

  19. Alternative splicing of repetitive units is responsible for the polydispersities of integumentary mucin B.1 (FIM-B.1) from Xenopus laevis.

    Science.gov (United States)

    Joba, W; Hoffmann, W

    1996-10-01

    Frog integumentary mucin B.1 (FIM-B.1) represents a polymorphic extracellular mosaic protein which contains tandemly arranged serine/threonine-rich modules as well as cysteine-rich domains. The latter are probably important for oligomerization of FIM-B.1 and have also been found in many proteins of the complement cascade as well as regions homologous to von Willebrand factor. The repetitive modules are targets for extensive O-glycosylation. Previous cDNA cloning experiments clearly established polydispersities within the same individual, which originate from deletions/insertions in the repetitive domain. Here, we analyse part of the corresponding genomic region. Each repetitive unit as well as the cysteine-rich domain is encoded by an individual class 1-1 exon typical of shuffled modules. Alternative splicing of these multiple cassettes creates the polydisperse FIM-B.1 transcripts.

  20. New method to study DNA sequences: the languages of evolution.

    Science.gov (United States)

    Spinelli, Gino; Mayer-Foulkes, David

    2008-04-01

    Recently, several authors have reported statistical evidence for deterministic dynamics in the flux of genetic information, suggesting that evolution involves the emergence and maintenance of a fractal landscape in DNA chains. Here we examine the idea that motif repetition lies at the origin of these statistical properties of DNA. To analyse repetition patterns we apply a modification of the BDS statistic, devised to analyze complex economic dynamics and adapted here to DNA sequence analysis. This provides a new method to detect structured signals in genetic information. We compare naturally occurring DNA sequences along the evolutionary tree with randomly generated sequences and also with simulated sequences with repetition motifs. For easier understanding, we also define a new statistic for a DNA sequence that constitutes a specific fingerprint. The new methods are applied to exon and intron DNA sequences, finding specific statistical differences. Moreover, by analysing DNA sequences of different species from Bacteria to Man, we explore the evolution of these linguistic DNA features along the evolutionary tree. The results are consistent with the idea that all the flux of DNA information need not be random, but may be structured along the evolutionary tree. The implications for evolutionary theory are discussed.

  1. Oral Language Skills Moderate Nonword Repetition Skills in Children with Dyslexia: A Meta-Analysis of the Role of Nonword Repetition Skills in Dyslexia

    Science.gov (United States)

    Melby-Lervag, Monica; Lervag, Arne

    2012-01-01

    We present a meta-analysis reviewing studies that have focused on the relationship between dyslexia and nonword repetition. The results show that children with dyslexia have poorer nonword repetition skills when compared to both chronological-age and reading-level controls. However, the severity of the nonword repetition problem varies…

  2. Oral Language Skills Moderate Nonword Repetition Skills in Children with Dyslexia: A Meta-Analysis of the Role of Nonword Repetition Skills in Dyslexia

    Science.gov (United States)

    Melby-Lervag, Monica; Lervag, Arne

    2012-01-01

    We present a meta-analysis reviewing studies that have focused on the relationship between dyslexia and nonword repetition. The results show that children with dyslexia have poorer nonword repetition skills when compared to both chronological-age and reading-level controls. However, the severity of the nonword repetition problem varies…

  3. Effect of repetitive mckenzie lumbar spine exercises on cardiovascular system

    Directory of Open Access Journals (Sweden)

    Agrawal Sonal S

    2014-07-01

    Full Text Available Background & Purpose: McKenzie exercises for the lumbar spine, which are done repeatedly, such as flexion in standing (FIS, extension in standing flexion in lying (FIL & extension in lying (EIL have been used in the management of low back pain for over three decades. The cardiovascular effects of exercises that involve postural stabilization, arm exercises and of exercises performed in lying are well known, but there are seldom studies performed to assess the cardiovascular effects of these commonly used McKenzie exercises. Therefore the study focused on evaluating the effects of 4 commonly used McKenzie exercises on the cardiovascular system. Methods: 80 subjects in the age group of 20-59 years were randomly assigned into 4 groups according to their age, such that such that each group comprised of an equal number of subjects & equal number of males & females. Each subject performed all the 4 exercises (FIS, EIS, FIL & EIL for 10, 15 & 20 repetitions respectively. Heart rate, blood pressure & rate pressure product were recorded before & after each set of repetitions & after each type of exercise. Results: Repetitive McKenzie lumbar spine exercises had cardiovascular effects in apparently healthy subjects (both male & female. Exercises performed in lying were hemodynamically more demanding than that performed in standing, also exercises involving flexion of the lumbar spine elicited greater cardiovascular demand as compared to extension exercises i.e. FIL>EIL>FIS>EIS irrespective of the number of repetitions, 10, 15 or 20. The cardiovascular demand for a given subject increased as the number of repetitions increased, for all the 4 exercises. Conclusion: McKenzie exercises when done repetitively have cardiovascular effects in healthy subjects.

  4. The neural correlates of picture naming facilitated by auditory repetition

    Directory of Open Access Journals (Sweden)

    Heath Shiree

    2012-02-01

    Full Text Available Abstract Background Overt repetition of auditorily presented words can facilitate picture naming performance in both unimpaired speakers and individuals with word retrieval difficulties, but the underlying neurocognitive mechanisms and longevity of such effects remain unclear. This study used functional magnetic resonance imaging to examine whether different neurological mechanisms underlie short-term (within minutes and long-term (within days facilitation effects from an auditory repetition task in healthy older adults. Results The behavioral results showed that both short- and long-term facilitated items were named significantly faster than unfacilitated items, with short-term items significantly faster than long-term items. Neuroimaging analyses identified a repetition suppression effect for long-term facilitated items, relative to short-term facilitated and unfacilitated items, in regions known to be associated with both semantic and phonological processing. A repetition suppression effect was also observed for short-term facilitated items when compared to unfacilitated items in a region of the inferior temporal lobe linked to semantic processing and object recognition, and a repetition enhancement effect when compared to long-term facilitated items in a posterior superior temporal region associated with phonological processing. Conclusions These findings suggest that different neurocognitive mechanisms underlie short- and long-term facilitation of picture naming by an auditory repetition task, reflecting both phonological and semantic processing. More specifically, the brain areas engaged were consistent with the view that long-term facilitation may be driven by a strengthening of semantic-phonological connections. Short-term facilitation, however, appears to result in more efficient semantic processing and/or object recognition, possibly in conjunction with active recognition of the phonological form.

  5. Use of long-range repetitive element polymorphism-PCR to differentiate Bacillus anthracis strains.

    Science.gov (United States)

    Brumlik, M J; Szymajda, U; Zakowska, D; Liang, X; Redkar, R J; Patra, G; Del Vecchio, V G

    2001-07-01

    The genome of Bacillus anthracis is extremely monomorphic, and thus individual strains have often proven to be recalcitrant to differentiation at the molecular level. Long-range repetitive element polymorphism-PCR (LR REP-PCR) was used to differentiate various B. anthracis strains. A single PCR primer derived from a repetitive DNA element was able to amplify variable segments of a bacterial genome as large as 10 kb. We were able to characterize five genetically distinct groups by examining 105 B. anthracis strains of diverse geographical origins. All B. anthracis strains produced fingerprints comprising seven to eight bands, referred to as "skeleton" bands, while one to three "diagnostic" bands differentiated between B. anthracis strains. LR REP-PCR fingerprints of B. anthracis strains showed very little in common with those of other closely related species such as B. cereus, B. thuringiensis, and B. mycoides, suggesting relative heterogeneity among the non-B. anthracis strains. Fingerprints from transitional non-B. anthracis strains, which possessed the B. anthracis chromosomal marker Ba813, scarcely resembled those observed for any of the five distinct B. anthracis groups that we have identified. The LR REP-PCR method described in this report provides a simple means of differentiating B. anthracis strains.

  6. Frobenius morphisms and stable module categories of repetitive algebras

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Let k be the algebraic closure of a finite field F_q and A be a finite dimensional k-algebra with a Frobenius morphism F.In the present paper we establish a relation between the stable module category of the repetitive algebra  of A and that of the repetitive algebra of the fixed-point algebra A~F.As an application,it is shown that the derived category of A~F is equivalent to the subcategory of F-stable objects in the derived category of A when A has a finite global dimension.

  7. Risk factors for hand-wrist disorders in repetitive work

    DEFF Research Database (Denmark)

    Thomsen, J. F.; Mikkelsen, S.; Andersen, JH

    2007-01-01

    (wrist pain and palpation tenderness) were determined in 3123 employees in 19 industrial settings. With the use of questionnaires and video recordings of homogenous work tasks number of wrist movements, hand force requirements and wrist position were analysed as risk factors for hand-wrist disorders......OBJECTIVES: To identify the risk of hand-wrist disorders related to repetitive movements, use of hand force and wrist position in repetitive monotonous work. METHODS: Using questionnaires and physical examinations, the prevalence and incidence of hand-wrist pain and possible extensor tendonitis...... were less consistent. Working with the hand in a non-neutral position could not be identified as a risk factor...

  8. Demonstration of a high repetition rate capillary discharge waveguide

    Energy Technology Data Exchange (ETDEWEB)

    Gonsalves, A. J., E-mail: ajgonsalves@lbl.gov; Pieronek, C.; Daniels, J.; Bulanov, S. S.; Waldron, W. L.; Mittelberger, D. E.; Leemans, W. P. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Liu, F.; Antipov, S.; Butler, J. E. [Euclid TechLabs, Gaithersburg, Maryland 20879 (United States); Bobrova, N. A.; Sasorov, P. V. [Keldysh Institute of Applied Mathematics, Moscow (Russian Federation)

    2016-01-21

    A hydrogen-filled capillary discharge waveguide operating at kHz repetition rates is presented for parameters relevant to laser plasma acceleration (LPA). The discharge current pulse was optimized for erosion mitigation with laser guiding experiments and MHD simulation. Heat flow simulations and measurements showed modest temperature rise at the capillary wall due to the average heat load at kHz repetition rates with water-cooled capillaries, which is promising for applications of LPAs such as high average power radiation sources.

  9. Medium Repetition Rate TEA Laser For Industrial Applications

    Science.gov (United States)

    Walter, Bruno

    1987-09-01

    The design and performance of an inexpensive compact repetitively pulsed TEA CO2 laser is described. The device uses a modified corona preionization technique and a fast transverse gas flow to achieve high repetition rates. An output energy of 500 mJ per pulse and an out-put power of 6.2W at 40Hz have been obtained. Due to the small energy needed for preionization, the efficiency of the device is high, whereas the gas dissociation is low when compared with commercial laser systems. This results in the relatively small fresh laser gas exchange of 20 ltr h-1 for long term operation.

  10. A mouse model of human repetitive mild traumatic brain injury

    OpenAIRE

    Kane, Michael J; Pérez, Mariana Angoa; Briggs, Denise I.; Viano, David C.; Kreipke, Christian W.; Kuhn, Donald M.

    2011-01-01

    A novel method for the study of repetitive mild traumatic brain injury (rmTBI) that models the most common form of head injury in humans is presented. Existing animal models of TBI impart focal, severe damage unlike that seen in repeated and mild concussive injuries, and few are configured for repetitive application. Our model is a modification of the Marmarou weight drop method and allows repeated head impacts to lightly anesthetized mice. A key facet of this method is the delivery of an imp...

  11. Convention, Repetition and Abjection: The Way of the Gothic

    OpenAIRE

    Łowczanin Agnieszka

    2014-01-01

    This paper employs Deleuze and Kristeva in an examination of certain Gothic conventions. It argues that repetition of these conventions- which endows Gothicism with formulaic coherence and consistence but might also lead to predictability and stylistic deadlock-is leavened by a novelty that Deleuze would categorize as literary “gift.” This particular kind of “gift” reveals itself in the fiction of successive Gothic writers on the level of plot and is applied to the repetition of the genre’s m...

  12. Urine concentrations of repetitive doses of inhaled salbutamol

    DEFF Research Database (Denmark)

    Elers, J; Pedersen, Lars; Henninge, J;

    2011-01-01

    We examined blood and urine concentrations of repetitive doses of inhaled salbutamol in relation to the existing cut-off value used in routine doping control. We compared the concentrations in asthmatics with regular use of beta2-agonists prior to study and healthy controls with no previous use...... of beta2-agonists. We enrolled 10 asthmatics and 10 controls in an open-label study in which subjects inhaled repetitive doses of 400 microgram salbutamol every second hour (total 1600 microgram), which is the permitted daily dose by the World Anti-Doping Agency (WADA). Blood samples were collected...

  13. A Brief Account on the Functions of Rhetorical Repetition

    Institute of Scientific and Technical Information of China (English)

    Li Yuping

    2000-01-01

    It is believed that using rhetoric devices precisely is of great importance for the English Learners, if they want to write good articles. Repetition is one of the rhetoric devices that is frequently used in English writing. This paper gives a brief account on the four functions of repetition by presenting some typical examples, focusing the reader's attention on the significance of this device in the English writing. The following are the four functions: an effective means of emphasis; making anidea clear and easier; generating emotional force; heightening a certain atmosphere.

  14. Genomic fingerprinting Acinetobacter baumannii: amplification of multiple inter-repetitive extragenic palindromic sequences.

    Science.gov (United States)

    Sheehan, C; Lynch, M; Cullen, C; Cryan, B; Greer, P; Fanning, S

    1995-09-01

    Acinetobacter species are important nosocomial pathogens. A rapid and sensitive identification system, capable of providing strain identity at the genetic level, is required to identify outbreak strains and facilitate the early implementation of infection control procedures. Repetitive extragenic palindromic (REP) elements, have been identified in numerous bacteria and these genomic sequences provide useful targets for DNA amplification. A method for amplifying inter-REP DNA sequences, REP-multiple arbitrary amplicon profiling (REP-MAAP), is described and applied to 29 Acinetobacter baumannii from clinical samples. Amplified polymorphic DNA patterns were demonstrated for all isolates and those displaying identical REP-MAAP patterns were considered identical at the genetic level. In the spring of 1993, 10 intensive care unit patients had endotracheal colonization with A. baumannii (five with REP-MAAP I and five with REP-MAAP II patterns). These findings suggested nosocomial transmission of organisms which was terminated by standard infection control measures. No further A. baumannii were detected until the winter of 1993 when isolates of different REP-MAAP groups emerged, suggesting that factors other than nosocomial transmission were implicated.

  15. DNA methylation of retrotransposons, DNA transposons and genes in sugar beet (Beta vulgaris L.).

    Science.gov (United States)

    Zakrzewski, Falk; Schmidt, Martin; Van Lijsebettens, Mieke; Schmidt, Thomas

    2017-03-03

    The methylation of cytosines shapes the epigenetic landscape of plant genomes, coordinates transgenerational epigenetic inheritance, represses activity of transposable elements (TEs), affects gene expression, and, hence, can influence the phenotype. Sugar beet (Beta vulgaris ssp. vulgaris), an important crop that accounts for 30% of the worldwide sugar needs, has a relatively small genome size (758 Mbp) consisting of approximately 485 Mbp repetitive DNA (64%) in particular, satellite DNA, retrotransposons, and DNA transposons. Genome-wide cytosine methylation in the sugar beet genome was studied in leaves and leaf-derived callus with a focus on repetitive sequences, including retrotransposons and DNA transposons, the major groups of repetitive DNA sequences and compared with gene methylation. Genes showed a specific methylation pattern for CG, CHG (H=A, C, and T), and CHH sites, whereas the TE pattern differed, depending on the classes 1 (retrotransposons) and 2 (DNA transposons), respectively. Along genes and TEs, the CG and CHG methylation was higher than that of adjacent genomic regions. In contrast to the relatively low CHH methylation in retrotransposons and genes, the level of CHH methylation in DNA transposons was strongly increased, pointing toward a functional role of asymmetric methylation in DNA transposon silencing. Comparison of genome-wide DNA methylation between sugar beet leaves and callus revealed a differential methylation upon tissue culture. Potential epialleles were hypomethylated (lower methylation) at CG and CHG sites in retrotransposons and genes and hypermethylated (higher methylation) at CHH sites in DNA transposons of callus when compared to leaves. This article is protected by copyright. All rights reserved.

  16. Repetitive DNAs highlight the role of chromosomal fusions in the karyotype evolution of Dascyllus species (Pomacentridae, Perciformes).

    Science.gov (United States)

    Getlekha, Nuntaporn; Molina, Wagner Franco; de Bello Cioffi, Marcelo; Yano, Cassia Fernanda; Maneechot, Nuntiya; Bertollo, Luiz Antonio Carlos; Supiwong, Weerayuth; Tanomtong, Alongklod

    2016-04-01

    The Dascyllus genus consists of 11 species spread over vast regions of the Indo-Pacific, showing remarkable reductions in the diploid chromosome numbers (2n). The present study analyzed the karyotypes and other chromosomal characteristics of D. trimaculatus (2n = 48; 2st + 46a; NF = 50), D. carneus (2n = 48; 2st + 46a; NF = 50) and D. aruanus (2n = 30; 18m + 2st + 10a; NF = 50) from the Thailand Gulf (Pacific Ocean) and D. melanurus (2n = 48; 2st + 46a; NF = 50) from the Andaman Sea (Indian Ocean), employing conventional cytogenetic analyses and the chromosomal mapping of repetitive DNAs, using 18S and 5S rDNA, telomeric sequences and (CA)15, (GA)15, and (CAA)10 microsatellites as probes. The C-positive heterochromatin was found in the centromeric regions of most chromosomal pairs and 18S rDNA phenotypes were single in all species. However, in D. aruanus (2n = 30), which harbors nine metacentric pairs; the 5S rDNA sites were located in the centromeric region of the shortest one. The mapping of the telomeric sequences in D. aruanus revealed the presence of interstitial telomeric sites (ITS) in the centromeric region of four metacentric pairs, with one of these pairs also displaying an additional ITS in the long arms. Distinct chromosomal markers confirmed the reduction of the 2n by chromosomal fusions, highlighting the precise characterization of these rearrangements by the cytogenetic mapping of the repetitive DNAs.

  17. Variations in Repetition Duration and Repetition Numbers Influence Muscular Activation and Blood Lactate Response in Protocols Equalized by Time Under Tension.

    Science.gov (United States)

    Lacerda, Lucas T; Martins-Costa, Hugo C; Diniz, Rodrigo C R; Lima, Fernando V; Andrade, André G P; Tourino, Frank D; Bemben, Michael G; Chagas, Mauro H

    2016-01-01

    The aim of this study was to investigate the impact of protocols equalized by the time under tension (TUT) but composed of different repetition durations and repetitions numbers on muscle activation and blood lactate concentration. Twenty-two males with previous experience in resistance training performed 2 training protocols (A and B) with the Smith machine bench press exercise, both with 3 sets, 3 minutes' rest, and 60% of 1 repetition maximum (1RM). Protocol A consisted of 6 repetitions with a 6-second repetition duration for each repetition, whereas in Protocol B the subjects performed 12 repetitions with a 3-second repetition duration for each repetition. Muscular activation was measured in the anterior deltoid, pectoralis major, and triceps brachii muscles while performing the 2 protocols, and the normalized root mean square of the electromyographic signal (EMGRMS) was calculated for each set. Blood lactate concentrations were measured during and until 12 minutes after the completion of each protocol. The results showed that the EMGRMS of all muscles increased during the sets and was higher in Protocol B when compared with Protocol A. Likewise, blood lactate concentrations also increased throughout the sets and were higher in Protocol B both during and after the completion of each training session. The data obtained in this study show that training protocols conducted with the same TUT, but with different configurations, produce distinct neuromuscular and metabolic responses so that performing higher repetition numbers with shorter repetition durations might be a more appropriate strategy to increase muscle activation and blood lactate concentration.

  18. Handedness, repetitive transcranial magnetic stimulation and bulimic disorders.

    Science.gov (United States)

    Van den Eynde, F; Broadbent, H; Guillaume, S; Claudino, A; Campbell, I C; Schmidt, U

    2012-05-01

    Repetitive Transcranial Magnetic Stimulation (rTMS) research in psychiatry mostly excludes left-handed participants. We recruited left-handed people with a bulimic disorder and found that stimulation of the left prefrontal cortex may result in different effects in left- and right-handed people. This highlights the importance of handedness and cortex lateralisation for rTMS.

  19. Intrinsic and Extrinsic Motivation for Stereotypic and Repetitive Behavior

    Science.gov (United States)

    Joosten, Annette V.; Bundy, Anita C.; Einfeld, Stewart L.

    2009-01-01

    This study provides evidence for intrinsic and extrinsic motivators for stereotypical and repetitive behavior in children with autism and intellectual disability and children with intellectual disability alone. We modified the Motivation Assessment Scale (MAS) (1988b); dividing it into intrinsic and extrinsic measures and adding items to assess…

  20. Decomposition of Repetition Priming Processes in Word Translation

    Science.gov (United States)

    Francis, Wendy S.; Duran, Gabriela; Augustini, Beatriz K.; Luevano, Genoveva; Arzate, Jose C.; Saenz, Silvia P.

    2011-01-01

    Translation in fluent bilinguals requires comprehension of a stimulus word and subsequent production, or retrieval and articulation, of the response word. Four repetition-priming experiments with Spanish-English bilinguals (N = 274) decomposed these processes using selective facilitation to evaluate their unique priming contributions and factorial…

  1. Auditory Repetition Priming Is Impaired in Pure Alexic Patients

    Science.gov (United States)

    Swick, Diane; Miller, Kimberly M.; Larsen, Jary

    2004-01-01

    Alexia without agraphia, or ''pure'' alexia, is an acquired impairment in reading that leaves writing skills intact. Repetition priming for visually presented words is diminished in pure alexia. However, it is not possible to verify whether this priming deficit is modality-specific or modality independent because reading abilities are compromised.…

  2. Repetition priming-induced changes in sensorimotor transmission.

    Science.gov (United States)

    Svensson, Erik; Evans, Colin G; Cropper, Elizabeth C

    2016-03-01

    When a behavior is repeated performance often improves, i.e., repetition priming occurs. Although repetition priming is ubiquitous, mediating mechanisms are poorly understood. We address this issue in the feeding network ofAplysia Similar to the priming observed elsewhere, priming inAplysiais stimulus specific, i.e., it can be either "ingestive" or "egestive." Previous studies demonstrated that priming alters motor and premotor activity. Here we sought to determine whether sensorimotor transmission is also modified. We report that changes in sensorimotor transmission do occur. We ask how they are mediated and obtain data that strongly suggest a presynaptic mechanism that involves changes in the "background" intracellular Ca(2+)concentration ([Ca(2+)]i) in primary afferents themselves. This form of plasticity has previously been described and generated interest due to its potentially graded nature. Manipulations that alter the magnitude of the [Ca(2+)]iimpact the efficacy of synaptic transmission. It is, however, unclear how graded control is exerted under physiologically relevant conditions. In the feeding system changes in the background [Ca(2+)]iare mediated by the induction of a nifedipine-sensitive current. We demonstrate that the extent to which this current is induced is altered by peptides (i.e., increased by a peptide released during the repetition priming of ingestive activity and decreased by a peptide released during the repetition priming of egestive activity). We suggest that this constitutes a behaviorally relevant mechanism for the graded control of synaptic transmission via the regulation of the [Ca(2+)]iin a neuron.

  3. A Study on Repetition Techniques in Persian Morphology

    Directory of Open Access Journals (Sweden)

    a Vafaie

    2011-06-01

    Full Text Available The speakers of any language, according to their constant need, coin some novel words in order to convey meaning, express ideas, thoughts, and their desires. In this process, they take advantage of their overt or covert linguistic competence. For instance, the derivative feature of Arabic language has contributed a lot to speakers of that language to create so many words with multiple meanings, all formed on the same stem. Likewise, English speakers make use of the derivative features, compounding, blending, and multiple processes of their language to create words. Similarly, in Persian language, the speakers make new words based on specific features of that language. There are five common processes applied in Persian language to form new words, among which blending, compounding, derivation, repetition or reduplication, clipping and acronyms are frequently used and the other techniques or processes have been neglected. Word repetition is one of the word formation processes and many words are made through this process. This study is an attempt to delve into the morphological processes of word repetition in Persian contemporary language according to the texts of three books, “Imaginary Perspectives in Persian Poetry”, “Let’s Listen to the Speech” and “with Holleh Convoy”. In addition, it strives to find a proper solution to the question of the Persian word formation processes in creating new words through repetition.

  4. Do Stimulus-Action Associations Contribute to Repetition Priming?

    Science.gov (United States)

    Dennis, Ian; Perfect, Timothy J.

    2013-01-01

    Despite evidence that response learning makes a major contribution to repetition priming, the involvement of response representations at the level of motor actions remains uncertain. Levels of response representation were investigated in 4 experiments that used different tasks at priming and test. Priming for stimuli that required congruent…

  5. Processing Speaker Variability in Repetition and Semantic/Associative Priming

    Science.gov (United States)

    Lee, Chao-Yang; Zhang, Yu

    2015-01-01

    The effect of speaker variability on accessing the form and meaning of spoken words was evaluated in two short-term priming experiments. In the repetition priming experiment, participants listened to repeated or unrelated prime-target pairs, in which the prime and target were produced by the same speaker or different speakers. The results showed…

  6. Autism and exergaming: effects on repetitive behaviors and cognition.

    Science.gov (United States)

    Anderson-Hanley, Cay; Tureck, Kimberly; Schneiderman, Robyn L

    2011-01-01

    Autism is a neurodevelopmental disorder that leads to impairment in social skills and delay in language development, and results in repetitive behaviors and restricted interests that impede academic and social involvement. Physical exercise has been shown to decrease repetitive behaviors in autistic children and improve cognitive function across the life-span. Exergaming combines physical and mental exercise simultaneously by linking physical activity movements to video game control and may yield better compliance with exercise. In this investigation, two pilot studies explored the potential behavioral and cognitive benefits of exergaming. In Pilot I, twelve children with autism spectrum disorders completed a control task and an acute bout of Dance Dance Revolution (DDR); in Pilot II, ten additional youths completed an acute bout of cyber cycling. Repetitive behaviors and executive function were measured before and after each activity. Repetitive behaviors significantly decreased, while performance on Digits Backwards improved following the exergaming conditions compared with the control condition. Additional research is needed to replicate these findings, and to explore the application of exergaming for the management of behavioral disturbance and to increase cognitive control in children on the autism spectrum.

  7. Orientation-Invariant Object Recognition: Evidence from Repetition Blindness

    Science.gov (United States)

    Harris, Irina M.; Dux, Paul E.

    2005-01-01

    The question of whether object recognition is orientation-invariant or orientation-dependent was investigated using a repetition blindness (RB) paradigm. In RB, the second occurrence of a repeated stimulus is less likely to be reported, compared to the occurrence of a different stimulus, if it occurs within a short time of the first presentation.…

  8. Piriform spider silk sequences reveal unique repetitive elements.

    Science.gov (United States)

    Perry, David J; Bittencourt, Daniela; Siltberg-Liberles, Jessica; Rech, Elibio L; Lewis, Randolph V

    2010-11-08

    Orb-weaving spider silk fibers are assembled from very large, highly repetitive proteins. The repeated segments contain, in turn, short, simple, and repetitive amino acid motifs that account for the physical and mechanical properties of the assembled fiber. Of the six orb-weaver silk fibroins, the piriform silk that makes the attachment discs, which lashes the joints of the web and attaches dragline silk to surfaces, has not been previously characterized. Piriform silk protein cDNAs were isolated from phage libraries of three species: A. trifasciata , N. clavipes , and N. cruentata . The deduced amino acid sequences from these genes revealed two new repetitive motifs: an alternating proline motif, where every other amino acid is proline, and a glutamine-rich motif of 6-8 amino acids. Similar to other spider silk proteins, the repeated segments are large (>200 amino acids) and highly homogenized within a species. There is also substantial sequence similarity across the genes from the three species, with particular conservation of the repetitive motifs. Northern blot analysis revealed that the mRNA is larger than 11 kb and is expressed exclusively in the piriform glands of the spider. Phylogenetic analysis of the C-terminal regions of the new proteins with published spidroins robustly shows that the piriform sequences form an ortholog group.

  9. Focus on form through task repetition in TBLT

    NARCIS (Netherlands)

    van de Guchte, M.; Braaksma, M.; Rijlaarsdam, G.; Bimmel, P.

    2015-01-01

    Because there has been little research on focus on form during the post-task phase in task-based language teaching, this experimental study investigates the effects of task repetition after having directed learners’ attention to form during the main task. The study comprises two interventions, where

  10. The neurobiology of repetitive behavior: …and men

    NARCIS (Netherlands)

    Langen, Marieke; Durston, Sarah; Kas, Martien J H; van Engeland, Herman; Staal, Wouter G

    2011-01-01

    In young, typically developing children, repetitive behavior similar to that in certain neuropsychiatric syndromes is common. Whereas this behavior is adaptive in typical development, in many disorders it forms a core component of symptoms and causes prominent impairment in the daily life of affecte

  11. Spierbelasting en RSI [Muscle load and repetitive strain injury (RSI)

    NARCIS (Netherlands)

    Hoozemans, M.J.M.; Visser, B.; Huysmans, M.A.; Speklé, E.M.; Dieën, J.H. van

    2005-01-01

    This paper presents an overview of theories concerning the development of RSI (repetitive strain injury), related to muscle disorders. Movement is a noisy process. The level of noise is affected by factors such as fatigue and psychosocial stress. In order for precision movements to be made in such

  12. Use of Repetitive Transcranial Magnetic Stimulation for Treatment in Psychiatry

    NARCIS (Netherlands)

    Aleman, Andre

    The potential of noninvasive neurostimulation by repetitive transcranial magnetic stimulation (rTMS) for improving psychiatric disorders has been studied increasingly over the past two decades. This is especially the case for major depression and for auditory verbal hallucinations in schizophrenia.

  13. Practicing novel, praxis-like movements: physiological effects of repetition

    Directory of Open Access Journals (Sweden)

    Joshua Benjamin Ewen

    2016-02-01

    Full Text Available Our primary goal was to develop and validate a task that could provide evidence about how humans learn praxis gestures, such as those involving the use of tools. To that end, we created a video-based task in which subjects view a model performing novel, meaningless one-handed actions with kinematics similar to praxis gestures. Subjects then imitated the movements with their right hand. Trials were repeated 6 times to examine practice effects. EEG was recorded during the task. As a control, subjects watched videos of a model performing a well-established (over learned tool-use gesture. These gestures were also imitated 6 times. Demonstrating convergent validity, EEG measures of task-related cortical activation were similar in topography and frequency between the novel gesture task and the overlearned, praxis gesture task. As in studies assessing motor skill learning with simpler tasks, cortical activation during novel gesture learning decreased as the same gestures were repeated. In the control condition, repetition of overlearned tool-use gestures were also associated with reductions in activation, though to a lesser degree. Given that even overlearned, praxis gestures show constriction of EEG activity with repetition, it is possible that that attentional effects drive some of the repetition effects seen in EEG measures of activation during novel gesture repetition.

  14. A repetitive 0.14 THz relativistic surface wave oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Wang Guangqiang; Tong Changjiang; Li Xiaoze; Wang Xuefeng; Li Shuang; Lu Xicheng [Northwest Institute of Nuclear Technology, P.O. Box 69-1, Xi' an 710024 (China); Wang Jianguo [Northwest Institute of Nuclear Technology, P.O. Box 69-1, Xi' an 710024 (China); School of Electronic and Information Engineering, Xi' an Jiaotong University, Xi' an 710049 (China)

    2013-04-15

    Preliminary experimental results of a repetitive 0.14 THz overmoded relativistic surface wave oscillator (RSWO) are presented in this paper. The repetitive RSWO is developed by using a rectangularly corrugated slow-wave structure with overmoded ratio of 3 and a foilless diode emitting annular electron beam with thickness of 0.5 mm. The high quality electron beams at the repetition rate of 10 are obtained over a wide range of diode voltage (180 kV < U < 240 kV) and current (700 A < I < 1.2 kA). The generation experiments of RSWO are conducted at an axial pulsed magnetic field whose maximum strength and duration can reach about 2.7 T and 1 s, respectively. The experimental results show that the RSWO successfully produces reasonable uniform terahertz pulses at repetition rate of 10, and the pulse duration, frequency, and power of a single pulse are about 1.5 ns, 0.154 THz, and 2.6 MW, respectively, whereas the dominated radiation mode of the RSWO is TM{sub 02}.

  15. Memory, emotion, and pupil diameter: Repetition of natural scenes.

    Science.gov (United States)

    Bradley, Margaret M; Lang, Peter J

    2015-09-01

    Recent studies have suggested that pupil diameter, like the "old-new" ERP, may be a measure of memory. Because the amplitude of the old-new ERP is enhanced for items encoded in the context of repetitions that are distributed (spaced), compared to massed (contiguous), we investigated whether pupil diameter is similarly sensitive to repetition. Emotional and neutral pictures of natural scenes were viewed once or repeated with massed (contiguous) or distributed (spaced) repetition during incidental free viewing and then tested on an explicit recognition test. Although an old-new difference in pupil diameter was found during successful recognition, pupil diameter was not enhanced for distributed, compared to massed, repetitions during either recognition or initial free viewing. Moreover, whereas a significant old-new difference was found for erotic scenes that had been seen only once during encoding, this difference was absent when erotic scenes were repeated. Taken together, the data suggest that pupil diameter is not a straightforward index of prior occurrence for natural scenes. © 2015 Society for Psychophysiological Research.

  16. Processing Speaker Variability in Repetition and Semantic/Associative Priming

    Science.gov (United States)

    Lee, Chao-Yang; Zhang, Yu

    2015-01-01

    The effect of speaker variability on accessing the form and meaning of spoken words was evaluated in two short-term priming experiments. In the repetition priming experiment, participants listened to repeated or unrelated prime-target pairs, in which the prime and target were produced by the same speaker or different speakers. The results showed…

  17. Do Stimulus-Action Associations Contribute to Repetition Priming?

    Science.gov (United States)

    Dennis, Ian; Perfect, Timothy J.

    2013-01-01

    Despite evidence that response learning makes a major contribution to repetition priming, the involvement of response representations at the level of motor actions remains uncertain. Levels of response representation were investigated in 4 experiments that used different tasks at priming and test. Priming for stimuli that required congruent…

  18. Finite-Repetition threshold for infinite ternary words

    Directory of Open Access Journals (Sweden)

    Golnaz Badkobeh

    2011-08-01

    Full Text Available The exponent of a word is the ratio of its length over its smallest period. The repetitive threshold r(a of an a-letter alphabet is the smallest rational number for which there exists an infinite word whose finite factors have exponent at most r(a. This notion was introduced in 1972 by Dejean who gave the exact values of r(a for every alphabet size a as it has been eventually proved in 2009. The finite-repetition threshold for an a-letter alphabet refines the above notion. It is the smallest rational number FRt(a for which there exists an infinite word whose finite factors have exponent at most FRt(a and that contains a finite number of factors with exponent r(a. It is known from Shallit (2008 that FRt(2=7/3. With each finite-repetition threshold is associated the smallest number of r(a-exponent factors that can be found in the corresponding infinite word. It has been proved by Badkobeh and Crochemore (2010 that this number is 12 for infinite binary words whose maximal exponent is 7/3. We show that FRt(3=r(3=7/4 and that the bound is achieved with an infinite word containing only two 7/4-exponent words, the smallest number. Based on deep experiments we conjecture that FRt(4=r(4=7/5. The question remains open for alphabets with more than four letters. Keywords: combinatorics on words, repetition, repeat, word powers, word exponent, repetition threshold, pattern avoidability, word morphisms.

  19. Investigating repetition and change in musical rhythm by functional MRI.

    Science.gov (United States)

    Danielsen, A; Otnæss, M K; Jensen, J; Williams, S C R; Ostberg, B C

    2014-09-05

    Groove-based rhythm is a basic and much appreciated feature of Western popular music. It is commonly associated with dance, movement and pleasure and is characterized by the repetition of a basic rhythmic pattern. At various points in the musical course, drum breaks occur, representing a change compared to the repeated pattern of the groove. In the present experiment, we investigated the brain response to such drum breaks in a repetitive groove. Participants were scanned with functional magnetic resonance imaging (fMRI) while listening to a previously unheard naturalistic groove with drum breaks at uneven intervals. The rhythmic pattern and the timing of its different parts as performed were the only aspects that changed from the repetitive sections to the breaks. Differences in blood oxygen level-dependent activation were analyzed. In contrast to the repetitive parts, the drum breaks activated the left cerebellum, the right inferior frontal gyrus (RIFG), and the superior temporal gyri (STG) bilaterally. A tapping test using the same stimulus showed an increase in the standard deviation of inter-tap-intervals in the breaks versus the repetitive parts, indicating extra challenges for auditory-motor integration in the drum breaks. Both the RIFG and STG have been associated with structural irregularity and increase in musical-syntactical complexity in several earlier studies, whereas the left cerebellum is known to play a part in timing. Together these areas may be recruited in the breaks due to a prediction error process whereby the internal model is being updated. This concurs with previous research suggesting a network for predictive feed-forward control that comprises the cerebellum and the cortical areas that were activated in the breaks.

  20. Refined repetitive sequence searches utilizing a fast hash function and cross species information retrievals

    Directory of Open Access Journals (Sweden)

    Reneker Jeff

    2005-05-01

    Full Text Available Abstract Background Searching for small tandem/disperse repetitive DNA sequences streamlines many biomedical research processes. For instance, whole genomic array analysis in yeast has revealed 22 PHO-regulated genes. The promoter regions of all but one of them contain at least one of the two core Pho4p binding sites, CACGTG and CACGTT. In humans, microsatellites play a role in a number of rare neurodegenerative diseases such as spinocerebellar ataxia type 1 (SCA1. SCA1 is a hereditary neurodegenerative disease caused by an expanded CAG repeat in the coding sequence of the gene. In bacterial pathogens, microsatellites are proposed to regulate expression of some virulence factors. For example, bacteria commonly generate intra-strain diversity through phase variation which is strongly associated with virulence determinants. A recent analysis of the complete sequences of the Helicobacter pylori strains 26695 and J99 has identified 46 putative phase-variable genes among the two genomes through their association with homopolymeric tracts and dinucleotide repeats. Life scientists are increasingly interested in studying the function of small sequences of DNA. However, current search algorithms often generate thousands of matches – most of which are irrelevant to the researcher. Results We present our hash function as well as our search algorithm to locate small sequences of DNA within multiple genomes. Our system applies information retrieval algorithms to discover knowledge of cross-species conservation of repeat sequences. We discuss our incorporation of the Gene Ontology (GO database into these algorithms. We conduct an exhaustive time analysis of our system for various repetitive sequence lengths. For instance, a search for eight bases of sequence within 3.224 GBases on 49 different chromosomes takes 1.147 seconds on average. To illustrate the relevance of the search results, we conduct a search with and without added annotation terms for the

  1. Active power filter for harmonic compensation using a digital dual-mode-structure repetitive control approach

    DEFF Research Database (Denmark)

    Zou, Zhixiang; Wang, Zheng; Cheng, Ming;

    2012-01-01

    This paper presents an digital dual-mode-structure repetitive control approach for the single-phase shunt active power filter (APF), which aims to enhance the tracking ability and eliminate arbitrary order harmonic. The proposed repetitive control scheme blends the characteristics of both odd......-harmonic repetitive control and even-harmonic repetitive control. Moreover, the convergence rate is faster than conventional repetitive controller. Additionally, the parameters have been designed and optimized for the dual-mode structure repetitive control to improve the performance of APF system. Experimental...... results on a laboratory setup are given to verify the proposed control scheme....

  2. Repetitive sequence analysis and karyotyping reveal different genome evolution and speciation of diploid and tetraploid Tripsacum dactyloides

    Directory of Open Access Journals (Sweden)

    Qilin Zhu

    2016-08-01

    Full Text Available In the subtribe Maydeae, Tripsacum and Zea are closely related genera. Tripsacum is a horticultural crop widely used as pasture forage. Previous studies suggested that Tripsacum might play an important role in maize origin and evolution. However, our understanding of the genomics and the evolution of Tripsacum remains limited. In this study, two diploids, T. dactyloides var. meridionale (2n = 36, MR and T. dactyloides (2n = 36, DD, and one tetraploid, T. dactyloides (2n = 72, DL were sequenced by low-coverage genome sequencing followed by graph-based cluster analysis. The results showed that 63.23%, 59.20%, and 61.57% of the respective genome of MR, DD, and DL were repetitive DNA sequence. The proportions of different repetitive sequences varied greatly among the three species. Fluorescence in situ hybridization (FISH analysis of mitotic metaphase chromosomes with satellite repeats as the probes showed that the FISH signal patterns of DL were more similar to that of DD than to that of MR. Comparative analysis of the repeats also showed that DL shared more common repeat families with DD than with MR. Phylogenetic analysis of internal transcribed spacer region sequences further supported the evolutionary relationship among the three species. Repetitive sequences comparison showed that Tripsacum shared more repeat families with Zea than with Coix and Sorghum. Our study sheds new light on the genomics of Tripsacum and differential speciation in the Poaceae family.

  3. Creation of an ethanol-tolerant Saccharomyces cerevisiae strain by 266 nm laser radiation and repetitive cultivation.

    Science.gov (United States)

    Zhang, Min; Zhu, Rongrong; Zhang, Minfeng; Wang, Shilong

    2014-11-01

    Laser radiation is an efficient approach for rapid improvement of industrial microbial phenotypes. To improve ethanol tolerance in Saccharomyces cerevisiae strains, a 266 nm laser radiation with the use of repetitive cultivation was explored in this work. After irradiated by 266 nm laser radiation and repetitive cultivation, a genetically stable SM4 strain was obtained. The SM4 strain could grow on YPD plate with extra 15% (v/v) ethanol. Moreover, the ethanol production performance of SM4 strain was 29.25% more than that of the wild type strain when they were cultivated in 5% (v/v) ethanol fermentation medium for 72 h. The DNA mutation was the possible characters for the phenotype of SM4 strain. Overall, the 266 nm laser radiation and repetitive cultivation approach might be a novel and useful for breeding fermentation microorganisms. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  4. Autoantigenic proteins that bind recombinogenic sequences in Epstein-Barr virus and cellular DNA.

    OpenAIRE

    1994-01-01

    We have identified conserved autoantigenic cellular proteins that bind to G-rich sequence motifs in recombinogenic regions of Epstein-Barr virus (EBV) DNA. This binding activity, called TRBP, recognizes the EBV terminal repeats, a locus responsible for interconversion of linear and circular EBV DNA. We found that TRBP also binds to EBV DNA sequences involved in deletion of EBNA2, a gene product required for immortalization. We show that TRBP binds sequences present in repetitive cellular DNA,...

  5. Molecular cytogenetic characterization of chromosome site-specific repetitive sequences in the Arctic lamprey (Lethenteron camtschaticum, Petromyzontidae)

    Science.gov (United States)

    Ishijima, Junko; Uno, Yoshinobu; Nunome, Mitsuo; Nishida, Chizuko; Kuraku, Shigehiro

    2017-01-01

    Abstract All extant lamprey karyotypes are characterized by almost all dot-shaped microchromosomes. To understand the molecular basis of chromosome structure in lampreys, we performed chromosome C-banding and silver staining and chromosome mapping of the 18S–28S and 5S ribosomal RNA (rRNA) genes and telomeric TTAGGG repeats in the Arctic lamprey (Lethenteron camtschaticum). In addition, we cloned chromosome site-specific repetitive DNA sequences and characterized them by nucleotide sequencing, chromosome in situ hybridization, and filter hybridization. Three types of repetitive sequences were detected; a 200-bp AT-rich repetitive sequence, LCA-EcoRIa that co-localized with the 18S–28S rRNA gene clusters of 3 chromosomal pairs; a 364-bp AT-rich LCA-EcoRIb sequence that showed homology to the EcoRI sequence family from the sea lamprey (Petromyzon marinus), which contains short repeats as centromeric motifs; and a GC-rich 702-bp LCA-ApaI sequence that was distributed on nearly all chromosomes and showed significant homology with the integrase-coding region of a Ty3/Gypsy family long terminal repeat (LTR) retrotransposon. All three repetitive sequences are highly conserved within the Petromyzontidae or within Petromyzontidae and Mordaciidae. Molecular cytogenetic characterization of these site-specific repeats showed that they may be correlated with programed genome rearrangement (LCA-EcoRIa), centromere structure and function (LCA-EcoRIb), and site-specific amplification of LTR retroelements through homogenization between non-homologous chromosomes (LCA-ApaI). PMID:28025319

  6. The mitochondrial genomes of sponges provide evidence for multiple invasions by Repetitive Hairpin-forming Elements (RHE

    Directory of Open Access Journals (Sweden)

    Lavrov Dennis V

    2009-12-01

    Full Text Available Abstract Background The mitochondrial (mt genomes of sponges possess a variety of features, which appear to be intermediate between those of Eumetazoa and non-metazoan opisthokonts. Among these features is the presence of long intergenic regions, which are common in other eukaryotes, but generally absent in Eumetazoa. Here we analyse poriferan mitochondrial intergenic regions, paying particular attention to repetitive sequences within them. In this context we introduce the mitochondrial genome of Ircinia strobilina (Lamarck, 1816; Demospongiae: Dictyoceratida and compare it with mtDNA of other sponges. Results Mt genomes of dictyoceratid sponges are identical in gene order and content but display major differences in size and organization of intergenic regions. An even higher degree of diversity in the structure of intergenic regions was found among different orders of demosponges. One interesting observation made from such comparisons was of what appears to be recurrent invasions of sponge mitochondrial genomes by repetitive hairpin-forming elements, which cause large genome size differences even among closely related taxa. These repetitive hairpin-forming elements are structurally and compositionally divergent and display a scattered distribution throughout various groups of demosponges. Conclusion Large intergenic regions of poriferan mt genomes are targets for insertions of repetitive hairpin- forming elements, similar to the ones found in non-metazoan opisthokonts. Such elements were likely present in some lineages early in animal mitochondrial genome evolution but were subsequently lost during the reduction of intergenic regions, which occurred in the Eumetazoa lineage after the split of Porifera. Porifera acquired their elements in several independent events. Patterns of their intra-genomic dispersal can be seen in the mt genome of Vaceletia sp.

  7. 76 FR 44489 - Medical Devices; Neurological Devices; Classification of Repetitive Transcranial Magnetic...

    Science.gov (United States)

    2011-07-26

    ... transcranial magnetic stimulation (rTMS) system into class II (special controls). The Agency is classifying...; Classification of Repetitive Transcranial Magnetic Stimulation System AGENCY: Food and Drug Administration, HHS... entitled ``Class II Special Controls Guidance Document: Repetitive Transcranial Magnetic......

  8. Repetitive motion planning and control of redundant robot manipulators

    CERN Document Server

    Zhang, Yunong

    2013-01-01

    Repetitive Motion Planning and Control of Redundant Robot Manipulators presents four typical motion planning schemes based on optimization techniques, including the fundamental RMP scheme and its extensions. These schemes are unified as quadratic programs (QPs), which are solved by neural networks or numerical algorithms. The RMP schemes are demonstrated effectively by the simulation results based on various robotic models; the experiments applying the fundamental RMP scheme to a physical robot manipulator are also presented. As the schemes and the corresponding solvers presented in the book have solved the non-repetitive motion problems existing in redundant robot manipulators, it is of particular use in applying theoretical research based on the quadratic program for redundant robot manipulators in industrial situations. This book will be a valuable reference work for engineers, researchers, advanced undergraduate and graduate students in robotics fields. Yunong Zhang is a professor at The School of Informa...

  9. Perseveration and other repetitive verbal behaviors: functional dissociations.

    Science.gov (United States)

    Christman, Sarah S; Boutsen, Frank R; Buckingham, Hugh W

    2004-11-01

    This article will review types of perseveration from a neurolinguistic perspective. During the course of the article, continuous, stuck-in-set, and recurrent perseveration will be placed in contradistinction to several other types of repetitive behaviors commonly associated with neurogenic communication disorders. These include echolalia in mixed transcortical aphasia; conduite d'approche and conduite d'ecart in fluent aphasias; lexical and nonlexical automatisms in nonfluent aphasias; palilalia in neuromotor disorders, such as Parkinson's disease (PD); and sound, syllable, word, and phrase repetitions in neurogenic stuttering. When differentiating these phenomena from perseveration, it is helpful to consider the salient factors that condition observed behaviors in individual patients, such as overall speech fluency, inventory of available utterances, nature of eliciting tasks, and propositionality of responses. Information such as communication disorder diagnosis, underlying etiology, and known sites of lesion from each patient's total clinical profile may also assist with differentiation.

  10. Fine tuning of micropillar cavity modes through repetitive oxidations

    CERN Document Server

    Bakker, Morten P; Snijders, Henk; Truong, Tuan-Ahn; Petroff, Pierre M; Bouwmeester, Dirk; van Exter, Martin P

    2013-01-01

    Repetitive wet thermal oxidations of a tapered oxide aperture in a micropillar structure are demonstrated. After each oxidation step the con?fined optical modes are analyzed at room temperature. Three regimes are identi?fied. First, the optical con?finement increases when the aperture oxidizes towards the center. Then, the cavity modes shift by more than 30 nm, when the taper starts to oxidize through the center, leading to a decrease in the optical path length. Finally, the resonance frequency levels o?f, when the aperture is oxidized all the way through the micropillar, but confi?ned optical modes with a high quality factor remain. This repetitive oxidation technique therefore enables precise control of the optical cavity volume or wavelength.

  11. Interaction of Repetitively Pulsed High Energy Laser Radiation With Matter

    Science.gov (United States)

    Hugenschmidt, Manfred

    1986-10-01

    The paper is concerned with laser target interaction processes involving new methods of improving the overall energy balance. As expected theoretically, this can be achieved with high repetition rate pulsed lasers even for initially highly reflecting materials, such as metals. Experiments were performed by using a pulsed CO2 laser at mean powers up to 2 kW and repetition rates up to 100 Hz. The rates of temperature rise of aluminium for example were thereby increased by lore than a factor of 3 as compared to cw-radiation of comparable power density. Similar improvements were found for the overall absorptivities that were increased by this method by more than an order of magnitude.

  12. Skill learning and repetition priming in Alzheimer's disease.

    Science.gov (United States)

    Grober, E; Ausubel, R; Sliwinski, M; Gordon, B

    1992-10-01

    While perceptual-motor learning occurs normally in Alzheimer's disease (AD) patients, their ability to acquire the skill of reading transformed text has not been well delineated. AD patients and matched controls were timed as they read two blocks of words presented in mirror image. Control subjects displayed both skill learning and repetition priming, whereas AD patients displayed only repetition priming. Skill learning in AD patients was associated with their ability to complete verbal analogies. They displayed the expected impairment in recognition for the words from the mirror reading task. The failure of AD patients to acquire the mirror reading skill can be understood through a task analysis and may reflect an underlying deficit in abstract reasoning that precludes the development of appropriate pattern analyzing strategies needed to transform rotated text.

  13. Scan patterns when viewing natural scenes: emotion, complexity, and repetition.

    Science.gov (United States)

    Bradley, Margaret M; Houbova, Petra; Miccoli, Laura; Costa, Vincent D; Lang, Peter J

    2011-11-01

    Eye movements were monitored during picture viewing, and effects of hedonic content, perceptual composition, and repetition on scanning assessed. In Experiment 1, emotional and neutral pictures that were figure-ground compositions or more complex scenes were presented for a 6-s free viewing period. Viewing emotional pictures or complex scenes prompted more fixations and broader scanning of the visual array, compared to neutral pictures or simple figure-ground compositions. Effects of emotion and composition were independent, supporting the hypothesis that these oculomotor indices reflect enhanced information seeking. Experiment 2 tested an orienting hypothesis by repeatedly presenting the same pictures. Although repetition altered specific scan patterns, emotional, compared to neutral, picture viewing continued to prompt oculomotor differences, suggesting that motivationally relevant cues enhance information seeking in appetitive and defensive contexts. Copyright © 2011 Society for Psychophysiological Research.

  14. Repetitive transients extraction algorithm for detecting bearing faults

    Science.gov (United States)

    He, Wangpeng; Ding, Yin; Zi, Yanyang; Selesnick, Ivan W.

    2017-02-01

    Rolling-element bearing vibrations are random cyclostationary. This paper addresses the problem of noise reduction with simultaneous components extraction in vibration signals for faults diagnosis of bearing. The observed vibration signal is modeled as a summation of two components contaminated by noise, and each component composes of repetitive transients. To extract the two components simultaneously, an approach by solving an optimization problem is proposed in this paper. The problem adopts convex sparsity-based regularization scheme for decomposition, and non-convex regularization is used to further promote the sparsity but preserving the global convexity. A synthetic example is presented to illustrate the performance of the proposed approach for repetitive feature extraction. The performance and effectiveness of the proposed method are further demonstrated by applying to compound faults and single fault diagnosis of a locomotive bearing. The results show the proposed approach can effectively extract the features of outer and inner race defects.

  15. Improved Discrimination of Visual Stimuli Following Repetitive Transcranial Magnetic Stimulation

    OpenAIRE

    Waterston, Michael L.; Pack, Christopher C.

    2010-01-01

    BACKGROUND: Repetitive transcranial magnetic stimulation (rTMS) at certain frequencies increases thresholds for motor-evoked potentials and phosphenes following stimulation of cortex. Consequently rTMS is often assumed to introduce a "virtual lesion" in stimulated brain regions, with correspondingly diminished behavioral performance. METHODOLOGY/PRINCIPAL FINDINGS: Here we investigated the effects of rTMS to visual cortex on subjects' ability to perform visual psychophysical tasks. Contrary t...

  16. Striatal development in autism: repetitive behaviors and the reward circuitry

    OpenAIRE

    Kohls, Gregor; Yerys, Benjamin; Schultz, Robert T

    2014-01-01

    Autism spectrum disorder (ASD) is defined by two essential features – impaired social communication abilities, including deficits with social reciprocity, nonverbal communication and establishing relationships, and by the presence of restricted and repetitive behaviors and interests (RRBIs). Social deficits get the majority of attention both in science and in the popular media, but RRBIs are equally important in understanding autism. Although RRBIs are also seen in typically...

  17. Illusory sensation of movement induced by repetitive transcranial magnetic stimulation

    OpenAIRE

    Mark Schram Christensen; Jesper Lundbye-Jensen; Michael James Grey; Alexandra Damgaard Vejlby; Bo Belhage; Jens Bo Nielsen

    2010-01-01

    Human movement sense relies on both somatosensory feedback and on knowledge of the motor commands used to produce the movement. We have induced a movement illusion using repetitive transcranial magnetic stimulation over primary motor cortex and dorsal premotor cortex in the absence of limb movement and its associated somatosensory feedback. Afferent and efferent neural signalling was abolished in the arm with ischemic nerve block, and in the leg with spinal nerve block. Movement sensation was...

  18. Scan patterns when viewing natural scenes: Emotion, complexity, and repetition

    OpenAIRE

    Bradley, Margaret M.; Houbova, Petra; Miccoli,Laura; Costa, Vincent D.; Lang, Peter J.

    2011-01-01

    Eye movements were monitored during picture viewing and effects of hedonic content, perceptual composition, and repetition on scanning assessed. In Experiment 1, emotional and neutral pictures that were figure-ground compositions or more complex scenes were presented for a 6 s free viewing period. Viewing emotional pictures or complex scenes prompted more fixations and broader scanning of the visual array, compared to neutral pictures or simple figure-ground compositions. Effects of emotion a...

  19. Route to 100 TW Ti: Sapphire laser at repetitive mode

    Directory of Open Access Journals (Sweden)

    Teng Hao

    2013-11-01

    Full Text Available We demonstrated a 100 TW-class femtosecond Ti: sapphire laser running at repetition rate of 0.1 Hz by adding a stage amplifier in the 20 TW/10 Hz laser facility (XL-II. Pumping the new stage amplifier with the 25 J green Nd:glass laser, we successfully upgraded the laser energy to 3.4 J with duration of 29 fs, corresponding to a peak power of 117 TW.

  20. Don't Throw out the Baby with the Bathwater: Verbal Repetition, Mnemonics, and Active Learning

    Science.gov (United States)

    Saber, Jane Lee; Johnson, Richard D.

    2008-01-01

    The effectiveness of using verbal repetition and first-letter acronyms to teach a common marketing framework was examined in two experiments. In Experiment 1, 345 undergraduate students were exposed to the framework using one of four conditions: control, verbal repetition, acronym, and verbal repetition plus acronym in a traditional learning…

  1. Examining Restricted and Repetitive Behaviors in Young Children with Autism Spectrum Disorder during Two Observational Contexts

    Science.gov (United States)

    Stronach, Sheri; Wetherby, Amy M.

    2014-01-01

    This prospective study of the FIRST WORDS® Project examined restricted and repetitive behaviors in a sample of 55 toddlers at a mean age of 20 months who were later diagnosed with autism spectrum disorder. Restricted and repetitive behaviors were coded using the Repetitive Movement and Restricted Interest Scales in two video-recorded observation…

  2. Characterizing Caregiver Responses to Restricted and Repetitive Behaviors in Toddlers with Autism Spectrum Disorder

    Science.gov (United States)

    Harrop, Clare; Gulsrud, Amanda; Shih, Wendy; Hovsepyan, Lilit; Kasari, Connie

    2016-01-01

    Restricted and repetitive behaviors are a core feature of autism spectrum disorder. This descriptive study documented the presence of restricted and repetitive behaviors in 85 toddlers with autism spectrum disorder as they interacted with their caregiver in a play interaction. For each child restricted and repetitive behavior, a caregiver…

  3. On the repetitive operation of a self-switched transversely excited atmosphere CO2 laser

    Indian Academy of Sciences (India)

    Pallavi Raote; Gautam Patil; J Padma Nilaya; D J Biswas

    2010-11-01

    The repetition rate capability of self-switched transversely excited atmosphere (TEA) CO2 laser was studied for different gas flow configurations. For an optimized gas flow configuration, repetitive operation was achieved at a much smaller gas replenishment factor between two successive pulses when compared with repetitive systems energized by conventional pulsers.

  4. Effects of Material Emotional Valence on the Time Course of Massive Repetition Priming

    Science.gov (United States)

    Hu, Zhiguo; Liu, Hongyan; Zhang, John X.

    2010-01-01

    Learning through repetition is a fundamental form and also an effective method of language learning critical for achieving proficient and automatic language use. Massive repetition priming as a common research paradigm taps into the dynamic processes involved in repetition learning. Research with this paradigm has so far used only emotionally…

  5. FBFN-based adaptive repetitive control of nonlinearly parameterized systems

    Institute of Scientific and Technical Information of China (English)

    Wenli Sun; Hong Cai; Fu Zhao

    2013-01-01

    An adaptive repetitive control scheme is presented for a class of nonlinearly parameterized systems based on the fuzzy ba-sis function network (FBFN). The parameters of the fuzzy rules are tuned with adaptive schemes. To attenuate chattering effectively, the discontinuous control term is approximated by an adaptive PI control structure. The bound of the discontinuous control term is assumed to be unknown and estimated by an adaptive mecha-nism. Based on the Lyapunov stability theory, an adaptive repeti-tive control law is proposed to guarantee the closed-loop stability and the tracking performance. By means of FBFNs, which avoid the nonlinear parameterization from entering into the adaptive repetitive control, the control er singularity problem is solved. The proposed approach does not require an exact structure of the sys-tem dynamics, and the proposed control er is utilized to control a model of permanent-magnet linear synchronous motor subject to significant disturbances and parameter uncertainties. The simula-tion results demonstrate the effectiveness of the proposed method.

  6. A referential theory of the repetition-induced truth effect.

    Science.gov (United States)

    Unkelbach, Christian; Rom, Sarah C

    2017-03-01

    People are more likely to judge repeated statements as true compared to new statements, a phenomenon known as the illusory truth effect. The currently dominant explanation is an increase in processing fluency caused by prior presentation. We present a new theory to explain this effect. We assume that people judge truth based on coherent references for statements in memory. Due to prior presentation, repeated statements have more coherently linked references; thus, a repetition-induced truth effect follows. Five experiments test this theory. Experiment 1-3 show that both the amount and the coherence of references for a repeated statement influence judged truth. Experiment 4 shows that people also judge new statements more likely "true" when they share references with previously presented statements. Experiment 5 realizes theoretically predicted conditions under which repetition should not influence judged truth. Based on these data, we discuss how the theory relates to other explanations of repetition-induced truth and how it may integrate other truth-related phenomena and belief biases. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Illusory sensation of movement induced by repetitive transcranial magnetic stimulation.

    Directory of Open Access Journals (Sweden)

    Mark Schram Christensen

    Full Text Available Human movement sense relies on both somatosensory feedback and on knowledge of the motor commands used to produce the movement. We have induced a movement illusion using repetitive transcranial magnetic stimulation over primary motor cortex and dorsal premotor cortex in the absence of limb movement and its associated somatosensory feedback. Afferent and efferent neural signalling was abolished in the arm with ischemic nerve block, and in the leg with spinal nerve block. Movement sensation was assessed following trains of high-frequency repetitive transcranial magnetic stimulation applied over primary motor cortex, dorsal premotor cortex, and a control area (posterior parietal cortex. Magnetic stimulation over primary motor cortex and dorsal premotor cortex produced a movement sensation that was significantly greater than stimulation over the control region. Movement sensation after dorsal premotor cortex stimulation was less affected by sensory and motor deprivation than was primary motor cortex stimulation. We propose that repetitive transcranial magnetic stimulation over dorsal premotor cortex produces a corollary discharge that is perceived as movement.

  8. Route Repetition and Route Retracing: Effects of Cognitive Aging

    Directory of Open Access Journals (Sweden)

    Jan Malte Wiener

    2012-05-01

    Full Text Available Retracing a recently traveled route is a frequent navigation task when learning novel routes or exploring unfamiliar environments. In the present study we utilized virtual environments technology to investigate age-related differences in repeating and retracing a learned route. In the training phase of the experiment participants were guided along a route consisting of multiple intersections each featuring one unique landmark. In the subsequent test phase, they were guided along short sections of the route and asked to indicate overall travel direction (repetition or retracing, the direction required to continue along the route, and the next landmark they would encounter. Results demonstrate age-related deficits in all three tasks. More specifically, in contrast to younger participants, the older participants had greater problems during route retracing than during route repetition. While route repetition can be solved with egocentric response or route strategies, successfully retracing a route requires allocentric processing. The age-related deficits in route retracing are discussed in the context of impaired allocentric processing and shifts from allocentric to egocentric navigation strategies as a consequence of age-related hippocampal degeneration.

  9. Repetitive motor behavior: further characterization of development and temporal dynamics.

    Science.gov (United States)

    Muehlmann, Amber M; Bliznyuk, Nikolay; Duerr, Isaac; Lewis, Mark H

    2015-03-01

    Repetitive behaviors are diagnostic for autism spectrum disorders, common in related neurodevelopmental disorders, and normative in typical development. In order to identify factors that mediate repetitive behavior development, it is necessary to characterize the expression of these behaviors from an early age. Extending previous findings, we characterized further the ontogeny of stereotyped motor behavior both in terms of frequency and temporal organization in deer mice. A three group trajectory model provided a good fit to the frequencies of stereotyped behavior across eight developmental time points. Group based trajectory analysis using a measure of temporal organization of stereotyped behavior also resulted in a three group solution. Additionally, as the frequency of stereotyped behavior increased with age, the temporal distribution of stereotyped responses became increasingly regular or organized indicating a strong association between these measures. Classification tree and principal components analysis showed that accurate classification of trajectory group could be done with fewer observations. This ability to identify trajectory group membership earlier in development allows for examination of a wide range of variables, both experiential and biological, to determine their impact on altering the expected trajectory of repetitive behavior across development. Such studies would have important implications for treatment efforts in neurodevelopmental disorders such as autism.

  10. Repetition suppression: a means to index neural representations using BOLD?

    Science.gov (United States)

    Behrens, Timothy E. J.

    2016-01-01

    Understanding how the human brain gives rise to complex cognitive processes remains one of the biggest challenges of contemporary neuroscience. While invasive recording in animal models can provide insight into neural processes that are conserved across species, our understanding of cognition more broadly relies upon investigation of the human brain itself. There is therefore an imperative to establish non-invasive tools that allow human brain activity to be measured at high spatial and temporal resolution. In recent years, various attempts have been made to refine the coarse signal available in functional magnetic resonance imaging (fMRI), providing a means to investigate neural activity at the meso-scale, i.e. at the level of neural populations. The most widely used techniques include repetition suppression and multivariate pattern analysis. Human neuroscience can now use these techniques to investigate how representations are encoded across neural populations and transformed by relevant computations. Here, we review the physiological basis, applications and limitations of fMRI repetition suppression with a brief comparison to multivariate techniques. By doing so, we show how fMRI repetition suppression holds promise as a tool to reveal complex neural mechanisms that underlie human cognitive function. This article is part of the themed issue ‘Interpreting BOLD: a dialogue between cognitive and cellular neuroscience’. PMID:27574308

  11. Frequent non-reciprocal exchange in microsatellite-containing-DNA-regions of vertebrates

    DEFF Research Database (Denmark)

    Ziegler, J.O.; Wälther, M.; Linzer, T.R.

    2009-01-01

    Microsatellites are DNA-fragments containing short repetitive motifs with 2-10 bp. They are highly variable in most species and distributed throughout the whole genome. It is broadly accepted that their high degree of variability is closely associated with mispairing of DNA-strands during the rep...

  12. Molecular cytogenetic mapping of Cucumis sativus and C. melo using highly repetitive DNA sequences

    NARCIS (Netherlands)

    Koo, D.H.; Nam, Y.W.; Choi, D.; Bang, J.W.; Jong, de J.H.S.G.M.; Hur, Y.

    2010-01-01

    Chromosomes often serve as one of the most important molecular aspects of studying the evolution of species. Indeed, most of the crucial mutations that led to differentiation of species during the evolution have occurred at the chromosomal level. Furthermore, the analysis of pachytene chromosomes ap

  13. Meiotic recombination breakpoints are associated with open chromatin and enriched with repetitive DNA elements in potato

    Science.gov (United States)

    Meiotic recombination provides the framework for the genetic variation in natural and artificial populations of eukaryotes through the creation of novel haplotypes. Thus, determining the molecular characteristics of meiotic recombination remains essential for future plant breeding efforts, which hea...

  14. DNA Nanotechnology

    Science.gov (United States)

    Taniguchi, Masateru; Kawai, Tomoji

    2002-11-01

    DNA is one candidate of promising molecules for molecular electronic devices, since it has the double helix structure with pi-electron bases for electron transport, the address at 0.4 nm intervals, and the self-assembly. Electrical conductivity and nanostructure of DNA and modified DNA molecules are investigated in order to research the application of DNA in nanoelectronic devices. It has been revealed that DNA is a wide-gap semiconductor in the absence of doping. The conductivity of DNA has been controlled by chemical doping, electric field doping, and photo-doping. It has found that Poly(dG)[middle dot]Poly(dC) has the best conductivity and can function as a conducting nanowire. The pattern of DNA network is controlled by changing the concentration of the DNA solution.

  15. DNA Methylation

    OpenAIRE

    Alokail, Majed S.; Alenad, Amal M.

    2015-01-01

    The DNA of E. coli contains 19,120 6-methyladenines and 12,045 5-methylcytosines in addition to the four regular bases and these are formed by the postreplicative action of three DNA methyltransferases. The majority of the methylated bases are formed by the Dam and Dcm methyltransferases encoded by the dam (DNA adenine methyltransferase) and dcm (DNA cytosine methyltransferase) genes. Although not essential, Dam methylation is important for strand discrimination during repair of replication e...

  16. Assessing maladaptive repetitive thought in clinical disorders: A critical review of existing measures.

    Science.gov (United States)

    Samtani, Suraj; Moulds, Michelle L

    2017-04-01

    Rumination and worry have recently been grouped under the broader transdiagnostic construct of repetitive thought (Watkins, 2008). The purpose of this review is to provide an overview of scales used to assess repetitive thinking across a broad range of contexts: depression, anxiety, trauma, stress, illness, interpersonal difficulties, positive affect, and so forth. We also include scales developed or adapted for children and adolescents. In the extant literature, measures of repetitive thinking generally show small-to-moderate correlations with measures of psychopathology. This review highlights problems with the content validity of existing instruments; for example, confounds between repetitive thought and symptomatology, metacognitive beliefs, and affect. This review also builds on previous reviews by including newer transdiagnostic measures of repetitive thinking. We hope that this review will help to expand our understanding of repetitive thinking beyond the mood and anxiety disorders, and suggest ways forward in the measurement of repetitive thinking in individuals with comorbid conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Correlation study between the polymorphism of repetitive sequence in gene CAG of androgen receptor and the occurrence and progression of prostate cancer

    Institute of Scientific and Technical Information of China (English)

    Xiao-Lei Zhai; Xiao-Wei Qu; Liang Guo; Qian-He Ha

    2014-01-01

    Objective: To explore the relation between the polymorphism of repetitive sequence in gene CAG of androgen receptor (AR) and the susceptibility and clinical stages as well as pathological grading of prostate cancer among Han population. Method: Sixty-eight cases with prostate cancer hospitalized in Urinary Surgery Department from Feb. 2010 to Feb. 2012 and 60 healthy cases were chosen as research subjects. Methods of PCR and direct sequencing were adopted to detect DNA sequence of AR gene and the length of repetitive sequence in CAG. Results: The lengths of repetitive sequence in CAG of patients with prostate cancer and healthy people were (22.3±4.6) and (23.0±4.9), respectively showing no statistical significance. Comparing length (repetitive sequence of CAG)>22, those with that ﹤ 22 suffer a remarkably higher risk of prostate cancer (P﹤0.05). The number of repetitive sequence in CAG of patients at clinical stage C-D was less than that of patients at stage B, and the number of repetitive sequence in CAG of patients with poorly differentiated prostate cancer was also less than that of patients with moderately and highly differentiated prostate cancer. But there was no statistical significance int the difference (P>0.05); the proportion of patients with length ﹤22 at clinical stage C-D was much larger than that of patients at clinical stage B (P﹤0.05), and as the aggravation of pathological grading, the proportion of patients with the length ﹤22 was also remarkably increased and there was significant difference between patients with highly differentiated prostate cancer and those with poorly differentiated prostate cancer (P﹤0.05). Conclusions: There is correlation between the occurrence and development of prostate cancer in Han population and the polymorphism of repetitive sequence in gene CAG of androgen receptor. The less the number of repetitive sequence in CAG is, the higher the risk of prostate cancer will be and the more severe the clinical

  18. Dna Sequencing

    Science.gov (United States)

    Tabor, Stanley; Richardson, Charles C.

    1995-04-25

    A method for sequencing a strand of DNA, including the steps off: providing the strand of DNA; annealing the strand with a primer able to hybridize to the strand to give an annealed mixture; incubating the mixture with four deoxyribonucleoside triphosphates, a DNA polymerase, and at least three deoxyribonucleoside triphosphates in different amounts, under conditions in favoring primer extension to form nucleic acid fragments complementory to the DNA to be sequenced; labelling the nucleic and fragments; separating them and determining the position of the deoxyribonucleoside triphosphates by differences in the intensity of the labels, thereby to determine the DNA sequence.

  19. Spectroscopic Investigation of a Repetitively-Pulsed Nanosecond Discharge

    Science.gov (United States)

    Yee, Benjamin T.

    This work reports on an investigation of a repetitively-pulsed nanosecond discharge (RPND) in helium over a range of 0.3-16.0 Torr. The discharge was studied experimentally via laser-absorption spectroscopy and opticals emission spectroscopy measurements. In concert with the experimental campaign, a global model of a helium plasma was developed with the aid of particle-in-cell simulations. The global model was then used to predict the population kinetics and emissions of the RPND. Synthesis of the results provided new data and insights on the development of the RPND. Among the results were direct measurements of the triplet metastable states during the excitation period. This period was found to be unexpectedly long at low pressures (less than or equal to 1.0 Torr), suggesting an excess in high-energy electrons as compared to an equilibrium distribution. Other phenomena such as a prominent return stroke and additional energy deposition by reflections in the transmission line were also identified. Estimates of the electric field and electron temperatures were obtained for several conditions. Furthermore, several optical methods for electron temperature measurement were evaluated for application to the discharge. Based on the global model simulations, the coronal model was found to apply to the line ratio of the 33S-23Po and 31S-2 1Po transitions, however further work is needed to ascertain its applicability to experimental discharges. These results provide new insight on the development of the repetitively-pulsed nanosecond discharge. Specifically, they reveal new information about the excited state dynamics within the discharge, the non-equilibrium nature of its electrons, and several avenues for future studies. This study extends the present understanding of repetitively-pulsed discharges, and advances the knowledge of energy coupling between electric fields and plasmas.

  20. Towards next-generation biodiversity assessment using DNA metabarcoding

    DEFF Research Database (Denmark)

    Taberlet, Pierre; Coissac, Eric; Pompanon, Francois

    2012-01-01

    amplification step, and comprehensive taxonomic reference libraries composed of whole organellar genomes and repetitive ribosomal nuclear DNA can be built based on the well-curated DNA extract collections maintained by standardized barcoding initiatives. The near-term future of DNA metabarcoding has an enormous......Virtually all empirical ecological studies require species identification during data collection. DNA metabarcoding refers to the automated identification of multiple species from a single bulk sample containing entire organisms or from a single environmental sample containing degraded DNA (soil......, water, faeces, etc.). It can be implemented for both modern and ancient environmental samples. The availability of next-generation sequencing platforms and the ecologists need for high-throughput taxon identification have facilitated the emergence of DNA metabarcoding. The potential power of DNA...

  1. Effective constitutive relations for large repetitive frame-like structures

    Science.gov (United States)

    Nayfeh, A. H.; Hefzy, M. S.

    1981-01-01

    Effective mechanical properties for large repetitive framelike structures are derived using combinations of strength of material and orthogonal transformation techniques. Symmetry considerations are used in order to identify independent property constants. The actual values of these constants are constructed according to a building block format which is carried out in the three consecutive steps: (1) all basic planar lattices are identified; (2) effective continuum properties are derived for each of these planar basic grids using matrix structural analysis methods; and (3) orthogonal transformations are used to determine the contribution of each basic set to the overall effective continuum properties of the structure.

  2. REDUCTION APPROACHES FOR VIBRATION CONTROL OF REPETITIVE STRUCTURES

    Institute of Scientific and Technical Information of China (English)

    CHEN Wei-min; SUN Dong-chang; WANG Da-jun; WEI Jian-ping; TONG Li-yong; WANG Quan

    2006-01-01

    The reduction approaches are presented for vibration control of symmetric,cyclic periodic and linking structures. The condensation of generalized coordinates, the locations of sensors and actuators, and the relation between system inputs and control forces are assumed to be set in a symmetric way so that the control system posses the same repetition as the structure considered. By employing proper transformations of condensed generalized coordinates and the system inputs, the vibration control of an entire system can be implemented by carrying out the control of a number of sub-structures, and thus the dimension of the control problem can be significantly reduced.

  3. A Linguistic Analysis of a Textual Repetition in Homer's Iliad

    Directory of Open Access Journals (Sweden)

    Alberto MANCO

    2011-01-01

    Full Text Available In Homer's Iliad can be detected some contiguous repetitions in the text (in the same verse or away from each other in an irrelevant way. They appear different from one another but they are related from semantic and morphological issues. An example is provided by the use of the form Hectōr in conjunction with schesō, the alternative form of ecsō. We argue that this cohesion is not a coincidence and we try to suggest an explanation.

  4. Atypical presentation of NREM arousal parasomnia with repetitive episodes.

    Science.gov (United States)

    Trajanovic, N N; Shapiro, C M; Ong, A

    2007-08-01

    The case report describes a distinct variant of non-REM (Rapid Eye Movement) arousal parasomnia, sleepwalking type, featuring repetitive abrupt arousals, mostly from slow-wave sleep, and various automatisms and semi-purposeful behaviours. The frequency of events and distribution throughout the night presented as a continuous status of parasomnia ('status parasomnicus'). The patient responded well to treatment typically administered for adult NREM parasomnias, and after careful review of the clinical presentation, objective findings and treatment outcome, sleep-related epilepsy was ruled out in favour of parasomnia.

  5. Background music for repetitive task performance of severely retarded individuals.

    Science.gov (United States)

    Richman, J S

    1976-11-01

    Environmental manipulation in the form of specific tempo background music was used to assist in the habilitation of severely retarded persons. Thirty institutionalized retarded males were tested on a repetitive manual performance task judged to be similar to the type of tasks found in sheltered workshops. Each subject received each of the background treatments noncontingently: no music, slow tempo music, regular tempo music, fast tempo music. The results indicated that the regular tempo of background music facilitated the greatest improvement in performance, suggesting that the effect of music on performance is more complex than the issue of contingent presentation.

  6. Repetitively Pulsed Electric Laser Acoustic Studies. Volume 1.

    Science.gov (United States)

    1983-09-01

    INGARD ET AL. SEP 83 UNCLASSIFIED APHAL-IR-83-2858-VOL-1 F336i5 86-C 2848 F/ 0/ 8, EEEmohEEEomhiE EohEEmhohEEEEE mhhhmmomhhlm...TR-83-2058, Vol 9, 0 REPETITIVELY PULSED ELECTRIC LASER ACOUSTIC STUDIES Volume I K. U. INGARD , CHARLES F. MCMILLAN uDEPARTMENT OF AERONAUTICS AND...CONTRACT OR GRANT NUMBER(s) K.U. Ingard and Charles F. McMillan F33615.80-C-2040 9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT. PROJECT

  7. High voltage high repetition rate pulse using Marx topology

    Science.gov (United States)

    Hakki, A.; Kashapov, N.

    2015-06-01

    The paper describes Marx topology using MOSFET transistors. Marx circuit with 10 stages has been done, to obtain pulses about 5.5KV amplitude, and the width of the pulses was about 30μsec with a high repetition rate (PPS > 100), Vdc = 535VDC is the input voltage for supplying the Marx circuit. Two Ferrite ring core transformers were used to control the MOSFET transistors of the Marx circuit (the first transformer to control the charging MOSFET transistors, the second transformer to control the discharging MOSFET transistors).

  8. About the Infinite Repetition of Histories in Space

    Directory of Open Access Journals (Sweden)

    Manuel Alfonseca

    2014-08-01

    Full Text Available This paper analyzes two different proposals, one by Ellis and Brundrit, based on classical relativistic cosmology, the other by Garriga and Vilenkin, based on the DH interpretation of quantum mechanics, both concluding that, in an infinite universe, planets and beings must be repeated an infinite number of times. We point to possible shortcomings in these arguments. We conclude that the idea of an infinite repetition of histories in space cannot be considered strictly speaking a consequence of current physics and cosmology. Such ideas should be seen rather as examples of «ironic science» in the terminology of John Horgan.

  9. Bottle microresonator broadband and low repetition rate frequency comb generator

    CERN Document Server

    Dvoyrin, V

    2016-01-01

    We propose a new type of broadband and low repetition rate frequency comb generator which has the shape of an elongated and nanoscale-shallow optical bottle microresonator created at the surface of an optical fiber. The free spectral range (FSR) of the broadband azimuthal eigenfrequency series of this resonator is the exact multiple of the FSR of the dense and narrowband axial series. The effective radius variation of the microresonator is close to a parabola with a nanoscale height which is greater or equal to lambda/2pi*n0 (here lambda is the characteristic radiation wavelength and n0 is the refractive index of the microresonator material). Overall, the microresonator possesses a broadband, small FSR, and accurately equidistant spectrum convenient for the generation of a broadband and low repetition rate optical frequency comb. It is shown that this comb can be generated by pumping with a cw laser, which radiation frequency matches a single axial eigenfrequency of the microresonator, or, alternatively, by p...

  10. Verbal behavior in Alzheimer disease patients: Analysis of phrase repetition

    Directory of Open Access Journals (Sweden)

    Juliana Francisca Cecato

    Full Text Available Abstract Language problems in the elderly with AD are due to the fact that deterioration occurs not only in semantic memory, but in a group of cognitive factors, evidenced by a deficiency in search strategies for linguistic information. Objectives: To evaluate phrase repetition in two cognitive tests, the MMSE and MoCA, in a group of Alzheimer disease patients (AD and normal controls. Methods: A Cross-sectional study was conducted involving 20 patients who sought medical assistance at a geriatric institute in Jundiaí, São Paulo. The subjects underwent a detailed clinical examination and neuropsychometric evaluation. All subjects with AD met DSM-IV and NINCDS-ADRDA criteria. Ten patients received a diagnosis of AD and 10 were healthy subjects, forming the control group (CG. Results: All participants correctly answered the phrase from the MMSE (phrase 1. The MoCA phrases (phrases 2 and 3 were correct in 80% and 90%, respectively in the CG and in 40% and 50%, respectively in the AD group. Conclusions: The MoCA test proved more effective in evaluating the echoic behavior in AD patients compared to the MMSE. The simpler phrase repetition task in the MMSE was found to be less sensitive in detecting mild language decline in AD patients.

  11. Effect of Airflows on Repetitive Nanosecond Volume Discharges

    Science.gov (United States)

    Tang, Jingfeng; Wei, Liqiu; Huo, Yuxin; Song, Jian; Yu, Daren; Zhang, Chaohai

    2016-03-01

    Atmospheric pressure discharges excited by repetitive nanosecond pulses have attracted significant attention for various applications. In this paper, a plate-plate discharge with airflows is excited by a repetitive nanosecond pulse generator. Under different experiment conditions, the applied voltages, discharge currents, and discharge images are recorded. The plasma images presented here indicate that the volume discharge modes vary with airflow speeds, and a diffuse and homogeneous volume discharge occurs at the speed of more than 35 m/s. The role of airflows provides different effects on the 2-stage pulse discharges. The 1st pulse currents nearly maintain consistency for different airflow speeds. However, the 2nd pulse current has a change trend of first decreasing and then rapidly increasing, and the value difference for 2nd pulse currents is about 20 A under different airflows. In addition, the experimental results are discussed according to the electrical parameters and discharge images. supported by National Natural Science Foundation of China (Nos. 51006027, 51437002, and 51477035)

  12. Rotated balance in humans due to repetitive rotational movement.

    Science.gov (United States)

    Zakynthinaki, M S; Milla, J Madera; De Durana, A López Diaz; Martínez, C A Cordente; Romo, G Rodríguez; Quintana, M Sillero; Molinuevo, J Sampedro

    2010-03-01

    We show how asymmetries in the movement patterns during the process of regaining balance after perturbation from quiet stance can be modeled by a set of coupled vector fields for the derivative with respect to time of the angles between the resultant ground reaction forces and the vertical in the anteroposterior and mediolateral directions. In our model, which is an adaption of the model of Stirling and Zakynthinaki (2004), the critical curve, defining the set of maximum angles one can lean to and still correct to regain balance, can be rotated and skewed so as to model the effects of a repetitive training of a rotational movement pattern. For the purposes of our study a rotation and a skew matrix is applied to the critical curve of the model. We present here a linear stability analysis of the modified model, as well as a fit of the model to experimental data of two characteristic "asymmetric" elite athletes and to a "symmetric" elite athlete for comparison. The new adapted model has many uses not just in sport but also in rehabilitation, as many work place injuries are caused by excessive repetition of unaligned and rotational movement patterns.

  13. Hemodynamic Profiles of Functional and Dysfunctional Forms of Repetitive Thinking.

    Science.gov (United States)

    Ottaviani, Cristina; Brosschot, Jos F; Lonigro, Antonia; Medea, Barbara; Van Diest, Ilse; Thayer, Julian F

    2017-04-01

    The ability of the human brain to escape the here and now (mind wandering) can take functional (problem solving) and dysfunctional (perseverative cognition) routes. Although it has been proposed that only the latter may act as a mediator of the relationship between stress and cardiovascular disease, both functional and dysfunctional forms of repetitive thinking have been associated with blood pressure (BP) reactivity of the same magnitude. However, a similar BP reactivity may be caused by different physiological determinants, which may differ in their risk for cardiovascular pathology. To examine the way (hemodynamic profile) and the extent (compensation deficit) to which total peripheral resistance and cardiac output compensate for each other in determining BP reactivity during functional and dysfunctional types of repetitive thinking. Fifty-six healthy participants randomly underwent a perseverative cognition, a mind wandering, and a problem solving induction, each followed by a 5-min recovery period while their cardiovascular parameters were continuously monitored. Perseverative cognition and problem solving (but not mind wandering) elicited BP increases of similar magnitude. However, perseverative cognition was characterized by a more vascular (versus myocardial) profile compared to mind wandering and problem solving. As a consequence, BP recovery was impaired after perseverative cognition compared to the other two conditions. Given that high vascular resistance and delayed recovery are the hallmarks of hypertension the results suggest a potential mechanism through which perseverative cognition may act as a mediator in the relationship between stress and risk for developing precursors to cardiovascular disease.

  14. Urine concentrations of repetitive doses of inhaled salbutamol

    DEFF Research Database (Denmark)

    Elers, J; Pedersen, Lars; Henninge, J

    2011-01-01

    We examined blood and urine concentrations of repetitive doses of inhaled salbutamol in relation to the existing cut-off value used in routine doping control. We compared the concentrations in asthmatics with regular use of beta2-agonists prior to study and healthy controls with no previous use...... of beta2-agonists. We enrolled 10 asthmatics and 10 controls in an open-label study in which subjects inhaled repetitive doses of 400 microgram salbutamol every second hour (total 1600 microgram), which is the permitted daily dose by the World Anti-Doping Agency (WADA). Blood samples were collected...... and the median ranged from 268 to 611 ng×mL (-1). No samples exceeded the WADA threshold value of 1000 ng×mL (-1) when corrected for the urine specific gravity. When not corrected one sample exceeded the cut-off value with urine concentration of 1082 ng×mL (-1). In conclusion we found no differences in blood...

  15. Multiple repetition time balanced steady-state free precession imaging.

    Science.gov (United States)

    Cukur, Tolga; Nishimura, Dwight G

    2009-07-01

    Although balanced steady-state free precession (bSSFP) imaging yields high signal-to-noise ratio (SNR) efficiency, the bright lipid signal is often undesirable. The bSSFP spectrum can be shaped to suppress the fat signal with scan-efficient alternating repetition time (ATR) bSSFP. However, the level of suppression is limited, and the pass-band is narrow due to its nonuniform shape. A multiple repetition time (TR) bSSFP scheme is proposed that creates a broad stop-band with a scan efficiency comparable with ATR-SSFP. Furthermore, the pass-band signal uniformity is improved, resulting in fewer shading/banding artifacts. When data acquisition occurs in more than a single TR within the multiple-TR period, the echoes can be combined to significantly improve the level of suppression. The signal characteristics of the proposed technique were compared with bSSFP and ATR-SSFP. The multiple-TR method generates identical contrast to bSSFP, and achieves up to an order of magnitude higher stop-band suppression than ATR-SSFP. In vivo studies at 1.5 T and 3 T demonstrate the superior fat-suppression performance of multiple-TR bSSFP.

  16. Final Report, Photocathodes for High Repetition Rate Light Sources

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Zvi, Ilan [Stony Brook University

    2014-04-20

    This proposal brought together teams at Brookhaven National Laboratory (BNL), Lawrence Berkeley National Laboratory (LBNL) and Stony Brook University (SBU) to study photocathodes for high repetition rate light sources such as Free Electron Lasers (FEL) and Energy Recovery Linacs (ERL). The work done under this grant comprises a comprehensive program on critical aspects of the production of the electron beams needed for future user facilities. Our program pioneered in situ and in operando diagnostics for alkali antimonide growth. The focus is on development of photocathodes for high repetition rate Free Electron Lasers (FELs) and Energy Recovery Linacs (ERLs), including testing SRF photoguns, both normal-conducting and superconducting. Teams from BNL, LBNL and Stony Brook University (SBU) led this research, and coordinated their work over a range of topics. The work leveraged a robust infrastructure of existing facilities and the support was used for carrying out the research at these facilities. The program concentrated in three areas: a) Physics and chemistry of alkali-antimonide cathodes b) Development and testing of a diamond amplifier for photocathodes c) Tests of both cathodes in superconducting RF photoguns and copper RF photoguns

  17. Resistance to change of operant variation and repetition.

    Science.gov (United States)

    Doughty, A H; Lattal, K A

    2001-09-01

    A multiple chained schedule was used to compare the relative resistance to change of variable and fixed four-peck response sequences in pigeons. In one terminal link, a response sequence produced food only if it occurred infrequently relative to 15 other response sequences (vary). In the other terminal link, a single response sequence produced food (repeat). Identical variable-interval schedules operated in the initial links. During baseline, lower response rates generally occurred in the vary initial link, and similar response and reinforcement rates occurred in each terminal link. Resistance of responding to prefeeding and three rates of response-independent food delivered during the intercomponent intervals then was compared between components. During each disruption condition, initial- and terminal-link response rates generally were more resistant in the vary component than in the repeat component. During the response-independent food conditions, terminal-link response rates were more resistant than initial-link response rates in each component, but this did not occur during prefeeding. Variation (in vary) and repetition (in repeat) both decreased during the response-independent food conditions in the respective components, but with relatively greater disruption in repeat. These results extend earlier findings demonstrating that operant variation is more resistant to disruption than is operant repetition and suggest that theories of response strength, such as behavioral momentum theory, must consider factors other than reinforcement rate. The implications of the results for understanding operant response classes are discussed.

  18. Highly differentiated ZW sex microchromosomes in the Australian Varanus species evolved through rapid amplification of repetitive sequences.

    Directory of Open Access Journals (Sweden)

    Kazumi Matsubara

    Full Text Available Transitions between sex determination systems have occurred in many lineages of squamates and it follows that novel sex chromosomes will also have arisen multiple times. The formation of sex chromosomes may be reinforced by inhibition of recombination and the accumulation of repetitive DNA sequences. The karyotypes of monitor lizards are known to be highly conserved yet the sex chromosomes in this family have not been fully investigated. Here, we compare male and female karyotypes of three Australian monitor lizards, Varanus acanthurus, V. gouldii and V. rosenbergi, from two different clades. V. acanthurus belongs to the acanthurus clade and the other two belong to the gouldii clade. We applied C-banding and comparative genomic hybridization to reveal that these species have ZZ/ZW sex micro-chromosomes in which the W chromosome is highly differentiated from the Z chromosome. In combination with previous reports, all six Varanus species in which sex chromosomes have been identified have ZZ/ZW sex chromosomes, spanning several clades on the varanid phylogeny, making it likely that the ZZ/ZW sex chromosome is ancestral for this family. However, repetitive sequences of these ZW chromosome pairs differed among species. In particular, an (AATn microsatellite repeat motif mapped by fluorescence in situ hybridization on part of W chromosome in V. acanthurus only, whereas a (CGGn motif mapped onto the W chromosomes of V. gouldii and V. rosenbergi. Furthermore, the W chromosome probe for V. acanthurus produced hybridization signals only on the centromeric regions of W chromosomes of the other two species. These results suggest that the W chromosome sequences were not conserved between gouldii and acanthurus clades and that these repetitive sequences have been amplified rapidly and independently on the W chromosome of the two clades after their divergence.

  19. Neuronal mechanisms and circuits underlying repetitive behaviors in mouse models of autism spectrum disorder.

    Science.gov (United States)

    Kim, Hyopil; Lim, Chae-Seok; Kaang, Bong-Kiun

    2016-01-20

    Autism spectrum disorder (ASD) refers to a broad spectrum of neurodevelopmental disorders characterized by three central behavioral symptoms: impaired social interaction, impaired social communication, and restricted and repetitive behaviors. However, the symptoms are heterogeneous among patients and a number of ASD mouse models have been generated containing mutations that mimic the mutations found in human patients with ASD. Each mouse model was found to display a unique set of repetitive behaviors. In this review, we summarize the repetitive behaviors of the ASD mouse models and variations found in their neural mechanisms including molecular and electrophysiological features. We also propose potential neuronal mechanisms underlying these repetitive behaviors, focusing on the role of the cortico-basal ganglia-thalamic circuits and brain regions associated with both social and repetitive behaviors. Further understanding of molecular and circuitry mechanisms of the repetitive behaviors associated with ASD is necessary to aid the development of effective treatments for these disorders.

  20. The informative value of type of repetition: Perceptual and conceptual fluency influences on judgments of truth.

    Science.gov (United States)

    Silva, Rita R; Garcia-Marques, Teresa; Reber, Rolf

    2017-05-01

    We contrast the effects of conceptual and perceptual fluency resulting from repetition in the truth effect. In Experiment 1, participants judged either verbatim or paraphrased repetitions, which reduce perceptual similarity to original statements. Judgments were made either immediately after the first exposure to the statements or after one week. Illusions of truth emerged for both types of repetition, with delay reducing both effects. In Experiment 2, participants judged verbatim and paraphrased repetitions with either the same or a contradictory meaning of original statements. In immediate judgments, illusions of truth emerged for repetitions with the same meaning and illusions of falseness for contradictory repetitions. In the delayed session, the illusion of falseness disappeared for contradictory statements. Results are discussed in terms of the contributions of recollection of stimulus details and of perceptual and conceptual fluency to illusions of truth at different time intervals and judgmental context conditions. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Understanding work related musculoskeletal pain: does repetitive work cause stress symptoms?

    DEFF Research Database (Denmark)

    Bonde, J. P.; Mikkelsen, S.; Andersen, JH

    2005-01-01

    for development of regional pain in repetitive work, stress symptoms would likely be on the causal path. AIMS: To examine whether objective measures of repetitive monotonous work are related to occurrence and development of stress symptoms. METHODS: In 1994-95, 2033 unskilled workers with continuous repetitive...... work and 813 workers with varied work were enrolled. Measures of repetitiveness and force requirements were quantified using video observations to obtain individual exposure estimates. Stress symptoms were recorded at baseline and after approximately one, two, and three years by the Setterlind Stress...... Profile Inventory. RESULTS: Repetitive work, task cycle time, and quantified measures of repetitive upper extremity movements including force requirements were not related to occurrence of stress symptoms at baseline or development of stress symptoms during three years of follow up. CONCLUSIONS...

  2. Sequence-Independent Cloning and Post-Translational Modification of Repetitive Protein Polymers through Sortase and Sfp-Mediated Enzymatic Ligation.

    Science.gov (United States)

    Ott, Wolfgang; Nicolaus, Thomas; Gaub, Hermann E; Nash, Michael A

    2016-04-11

    Repetitive protein-based polymers are important for many applications in biotechnology and biomaterials development. Here we describe the sequential additive ligation of highly repetitive DNA sequences, their assembly into genes encoding protein-polymers with precisely tunable lengths and compositions, and their end-specific post-translational modification with organic dyes and fluorescent protein domains. Our new Golden Gate-based cloning approach relies on incorporation of only type IIS BsaI restriction enzyme recognition sites using PCR, which allowed us to install ybbR-peptide tags, Sortase c-tags, and cysteine residues onto either end of the repetitive gene polymers without leaving residual cloning scars. The assembled genes were expressed in Escherichia coli and purified using inverse transition cycling (ITC). Characterization by cloud point spectrophotometry, and denaturing polyacrylamide gel electrophoresis with fluorescence detection confirmed successful phosphopantetheinyl transferase (Sfp)-mediated post-translational N-terminal labeling of the protein-polymers with a coenzyme A-647 dye (CoA-647) and simultaneous sortase-mediated C-terminal labeling with a GFP domain containing an N-terminal GG-motif in a one-pot reaction. In a further demonstration, we installed an N-terminal cysteine residue into an elastin-like polypeptide (ELP) that was subsequently conjugated to a single chain poly(ethylene glycol)-maleimide (PEG-maleimide) synthetic polymer, noticeably shifting the ELP cloud point. The ability to straightforwardly assemble repetitive DNA sequences encoding ELPs of precisely tunable length and to post-translationally modify them specifically at the N- and C- termini provides a versatile platform for the design and production of multifunctional smart protein-polymeric materials.

  3. Use of Repetitive Sequences for Molecular and Cytogenetic Characterization of Avena Species from Portugal.

    Science.gov (United States)

    Tomás, Diana; Rodrigues, Joana; Varela, Ana; Veloso, Maria Manuela; Viegas, Wanda; Silva, Manuela

    2016-02-04

    Genomic diversity of Portuguese accessions of Avena species--diploid A. strigosa and hexaploids A. sativa and A. sterilis--was evaluated through molecular and cytological analysis of 45S rDNA, and other repetitive sequences previously studied in cereal species--rye subtelomeric sequence (pSc200) and cereal centromeric sequence (CCS1). Additionally, retrotransposons and microsatellites targeting methodologies--IRAP (inter-retrotransposon amplified polymorphism) and REMAP (retrotransposon-microsatellite amplified polymorphism)--were performed. A very high homology was detected for ribosomal internal transcribed sequences (ITS1 and ITS2) between the species analyzed, although nucleolar organizing regions (NOR) fluorescent in situ hybridization (FISH) analysis revealed distinct number of Nor loci between diploid and hexaploid species. Moreover, morphological diversity, evidenced by FISH signals with different sizes, was observed between distinct accessions within each species. pSc200 sequences were for the first time isolated from Avena species but proven to be highly similar in all genotypes analyzed. The use of primers designed for CCS1 unraveled a sequence homologous to the Ty3/gypsy retrotransposon Cereba, that was mapped to centromeric regions of diploid and hexaploid species, being however restricted to the more related A and D haplomes. Retrotransposon-based methodologies disclosed species- and accessions-specific bands essential for the accurate discrimination of all genotypes studied. Centromeric, IRAP and REMAP profiles therefore allowed accurate assessment of inter and intraspecific variability, demonstrating the potential of these molecular markers on future oat breeding programs.

  4. Use of Repetitive Sequences for Molecular and Cytogenetic Characterization of Avena Species from Portugal

    Science.gov (United States)

    Tomás, Diana; Rodrigues, Joana; Varela, Ana; Veloso, Maria Manuela; Viegas, Wanda; Silva, Manuela

    2016-01-01

    Genomic diversity of Portuguese accessions of Avena species—diploid A. strigosa and hexaploids A. sativa and A. sterilis—was evaluated through molecular and cytological analysis of 45S rDNA, and other repetitive sequences previously studied in cereal species—rye subtelomeric sequence (pSc200) and cereal centromeric sequence (CCS1). Additionally, retrotransposons and microsatellites targeting methodologies—IRAP (inter-retrotransposon amplified polymorphism) and REMAP (retrotransposon-microsatellite amplified polymorphism)—were performed. A very high homology was detected for ribosomal internal transcribed sequences (ITS1 and ITS2) between the species analyzed, although nucleolar organizing regions (NOR) fluorescent in situ hybridization (FISH) analysis revealed distinct number of Nor loci between diploid and hexaploid species. Moreover, morphological diversity, evidenced by FISH signals with different sizes, was observed between distinct accessions within each species. pSc200 sequences were for the first time isolated from Avena species but proven to be highly similar in all genotypes analyzed. The use of primers designed for CCS1 unraveled a sequence homologous to the Ty3/gypsy retrotransposon Cereba, that was mapped to centromeric regions of diploid and hexaploid species, being however restricted to the more related A and D haplomes. Retrotransposon-based methodologies disclosed species- and accessions-specific bands essential for the accurate discrimination of all genotypes studied. Centromeric, IRAP and REMAP profiles therefore allowed accurate assessment of inter and intraspecific variability, demonstrating the potential of these molecular markers on future oat breeding programs. PMID:26861283

  5. Genomic organization of repetitive DNAs highlights chromosomal evolution in the genus Clarias (Clariidae, Siluriformes).

    Science.gov (United States)

    Maneechot, Nuntiya; Yano, Cassia Fernanda; Bertollo, Luiz Antonio Carlos; Getlekha, Nuntaporn; Molina, Wagner Franco; Ditcharoen, Sukhonthip; Tengjaroenkul, Bundit; Supiwong, Weerayuth; Tanomtong, Alongklod; de Bello Cioffi, Marcelo

    2016-01-01

    The genus Clarias (Clariidae, Siluriformes) contains at least 61 species naturally spread over vast regions of Asia, India and Africa. However, Clarias species have also been introduced in many different countries and represent the most widespread catfishes in the world. These fishes are also known as "walking catfishes" due to their ability to move over land. A large degree of chromosomal variation has been previously found in this family, mainly using conventional cytogenetic investigations, with diploid chromosome numbers ranging between 48 and 100. In this study, we analyzed the karyotype structure and distribution of four repetitive DNA sequences (5S and 18S rDNAs and (CA)15 and (GA)15 microsatellites) in three Clarias species (C. batrachus, C. gariepinus, C. macrocephalus), as well as in a probable natural hybrid of the two latter species from different Thailand river basins. Clarias gariepinus and C. macrocephalus had 2n = 56 and 2n = 54, respectively, as well as karyotypes composed mainly by metacentric and submetacentric chromosomes. Their karyotypes differed in the number and location of 5S and 18S rDNA sites and in the degree of microsatellite accumulation. An intermediate chromosomal pattern incorporating those of the parental species was found in the probable hybrid, confirming its interspecific origin. Clarias batrachus had 2n = 104 chromosomes and its karyotype was dominated by mainly acrocentric elements, indicating that unusual multiple centric fissions were involved in its karyotype differentiation. The karyotype of this species presented an unexpected dispersion of ribosomal DNAs, possessing 54 and 12 sites of 5S and 18S rDNAs, respectively, as well as a high accumulation and differential distribution of both microsatellite repeats, representing 'hot spots' for chromosomal rearrangement. Both conventional and molecular cytogenetic markers were useful tools for demonstrating remarkable evolutionary dynamism and highlighting multiple

  6. Repetitive flanking sequences challenge microsatellite marker development: a case study in the lepidopteran Melanargia galathea.

    Science.gov (United States)

    Schmid, Max; Csencsics, Daniela; Gugerli, Felix

    2016-11-01

    Microsatellite DNA families (MDF) are stretches of DNA that share similar or identical sequences beside nuclear simple-sequence repeat (nSSR) motifs, potentially causing problems during nSSR marker development. Primers positioned within MDFs can bind several times within the genome and might result in multiple banding patterns. It is therefore common practice to exclude MDF loci in the course of marker development. Here, we propose an approach to deal with multiple primer-binding sites by purposefully positioning primers within the detected repetitive element. We developed a new protocol to determine the family type and the primer position in relation to MDFs using the software packages repark and repeatmasker together with an in-house R script. We re-evaluated newly developed nSSR markers for the lepidopteran Marbled White (Melanargia galathea) and explored the implications of our results with regard to published data sets of the butterfly Euphydryas aurinia, the grasshopper Stethophyma grossum, the conifer Pinus cembra and the crucifer Arabis alpina. For M. galathea, we show that it is not only possible to develop reliable nSSR markers for MDF loci, but even to benefit from their presence in some cases: We used one unlabelled primer, successfully binding within an MDF, for two different loci in a multiplex PCR, combining this family primer with uniquely binding and fluorescently labelled primers outside of MDFs, respectively. As MDFs are abundant in many taxa, we propose to consider these during nSSR marker development in taxa concerned. Our new approach might help in reducing the number of tested primers during nSSR marker development. © 2016 John Wiley & Sons Ltd.

  7. rTMS of the occipital cortex abolishes Braille reading and repetition priming in blind subjects.

    Science.gov (United States)

    Kupers, R; Pappens, M; de Noordhout, A Maertens; Schoenen, J; Ptito, M; Fumal, A

    2007-02-27

    To study the functional involvement of the visual cortex in Braille reading, we applied repetitive transcranial magnetic stimulation (rTMS) over midoccipital (MOC) and primary somatosensory (SI) cortex in blind subjects. After rTMS of MOC, but not SI, subjects made significantly more errors and showed an abolishment of the improvement in reading speed following repetitive presentation of the same word list, suggesting a role of the visual cortex in repetition priming in the blind.

  8. Repetitive thinking and depressive symptoms in a normal population : responses to normal negative events

    OpenAIRE

    Larsen, Simen Mjøen

    2016-01-01

    Some theories view repetitive thinking as a maladaptive coping response that exacerbates depressive symptoms and explains the sex difference in depression. Other theories view repetitive thinking as the chief mechanism for solving complex social problems. A central theoretical assumption in evolutionary psychology is that psychological mechanisms are sensitive to modern cues to ancestral fitness-relevant contexts. The measures that are currently used to probe repetitive thinking does not refl...

  9. Peripheral and central changes combine to induce motor behavioral deficits in a moderate repetition task

    OpenAIRE

    Coq, Jacques-Olivier; Barr, Ann E.; Strata, Fabrizio; Russier, Michael; Kietrys, David M; Merzenich, Michael M.; Byl, Nancy N; Barbe, Mary F

    2009-01-01

    Repetitive motion disorders, such as carpal tunnel syndrome and focal hand dystonia, can be associated with tasks that require prolonged, repetitive behaviors. Previous studies using animal models of repetitive motion have correlated cortical neuroplastic changes or peripheral tissue inflammation with fine motor performance. However, the possibility that both peripheral and central mechanisms coexist with altered motor performance has not been studied. In this study, we investigated the relat...

  10. Relationship between repetitive firing and afterhyperpolarizations in human neocortical neurons.

    Science.gov (United States)

    Lorenzon, N M; Foehring, R C

    1992-02-01

    1. Human neocortical neurons fire repetitively in response to long depolarizing current injections. The slope of the relationship between average firing frequency and injected current (f-I slope) was linear or bilinear in these cells. The mean steady-state f-I slope (average of the last 500 ms of a 1-s firing episode) was 57.8 Hz/nA. The instantaneous firing rate decreased with time during a 1-s constant-current injection (spike frequency adaptation). Also, human neurons exhibited habituation in response to a 1-s current stimulus repeated every 2 s. 2. Afterhyperpolarizations (AHPs) reflect the active ionic conductances after action potentials. We studied AHPs with the use of intracellular recordings and pharmacological manipulations in the in vitro slice preparation to 1) gain insight into the ionic mechanisms underlying the AHPs and 2) elucidate the role that the underlying currents play in the functional behavior of human cortical neurons. 3. We have classified three AHPs in human neocortical neurons on the basis of their time courses: fast, medium, and slow. The amplitude of the AHPs was dependent on stimulus intensity and duration, number and frequency of spikes, and membrane potential. 4. The fast AHP had a reversal potential of -65 mV and was eliminated in extracellular Co2+, tetraethylammonium (TEA) or 4-aminopyridine, and intracellular TEA or CsCl. These manipulations also caused an increase in spike width. 5. The medium AHP had a reversal potential of -90 to -93 mV (22-24 mV hyperpolarized from mean resting potential). This AHP was reduced by Co2+, apamin, tubocurare, muscarine, norepinephrine (NE), and serotonin (5-HT). Pharmacological manipulations suggest that the medium AHP is produced in part by 1) a Ca-dependent K+ current and 2) a time-dependent anomalous rectifier (IH). 6. The slow AHP reversed at -83 to -87 mV (14-18 mV hyperpolarized from mean resting potential). This AHP was diminished by Co2+, muscarine, NE, and 5-HT. The pharmacology of the

  11. DNA glue

    DEFF Research Database (Denmark)

    Filichev, Vyacheslav V; Astakhova, Irina V.; Malakhov, Andrei D.

    2008-01-01

    Significant alterations in thermal stability of parallel DNA triplexes and antiparallel duplexes were observed upon changing the attachment of ethynylpyrenes from para to ortho in the structure of phenylmethylglycerol inserted as a bulge into DNA (TINA). Insertions of two ortho-TINAs as a pseudo...

  12. An Optimal Seed Based Compression Algorithm for DNA Sequences

    Directory of Open Access Journals (Sweden)

    Pamela Vinitha Eric

    2016-01-01

    Full Text Available This paper proposes a seed based lossless compression algorithm to compress a DNA sequence which uses a substitution method that is similar to the LempelZiv compression scheme. The proposed method exploits the repetition structures that are inherent in DNA sequences by creating an offline dictionary which contains all such repeats along with the details of mismatches. By ensuring that only promising mismatches are allowed, the method achieves a compression ratio that is at par or better than the existing lossless DNA sequence compression algorithms.

  13. DIFFERENT RESULTS BY DIFFERENT COMMERCIAL TAQ DNA POLYMERASE IN RAPD

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    @@ RAPD (Random Amplified Polymorphic DNA) technique has been widely used in animal, plant, human and microorganism research since it was first established by Williams in 1990[1-3]. But, because of low annealed temperature and short 10-nt primers, the resolution and repetition is low in RAPD. The stability of RAPD is influenced by many factors such as the concentration of template, primers, dNTP, Mg++,and Taq DNA polymerase[4-6]. The influence on amplified products of different commercial Taq DNA polymerase in RAPD was studied in this paper.

  14. Establishing the baseline level of repetitive element expression in the human cortex

    National Research Council Canada - National Science Library

    Tyekucheva, Svitlana; Yolken, Robert H; McCombie, W Richard; Parla, Jennifer; Kramer, Melissa; Wheelan, Sarah J; Sabunciyan, Sarven

    2011-01-01

    .... Hence, we performed whole transcriptome sequencing to investigate the expression of repetitive elements in human frontal cortex using postmortem tissue obtained from the Stanley Medical Research Institute...

  15. Movement repetitions in physical and occupational therapy during spinal cord injury rehabilitation.

    Science.gov (United States)

    Zbogar, D; Eng, J J; Miller, W C; Krassioukov, A V; Verrier, M C

    2017-02-01

    Longitudinal observational study. To quantify the amount of upper- and lower-extremity movement repetitions (that is, voluntary movements as part of a functional task or specific motion) occurring during inpatient spinal cord injury (SCI), physical (PT) and occupational therapy (OT), and examine changes over the inpatient rehabilitation stay. Two stand-alone inpatient SCI rehabilitation centers. Participants: A total of 103 patients were recruited through consecutive admissions to SCI rehabilitation. Trained assistants observed therapy sessions and obtained clinical outcome measures in the second week following admission and in the second to last week before discharge. PT and OT time, upper- and lower-extremity repetitions and changes in these outcomes over the course of rehabilitation stay. We observed 561 PT and 347 OT sessions. Therapeutic time comprised two-thirds of total therapy time. Summed over PT and OT, the median upper-extremity repetitions in patients with paraplegia were 7 repetitions and in patients with tetraplegia, 42 repetitions. Lower-extremity repetitions and steps primarily occurred in ambulatory patients and amounted to 218 and 115, respectively (summed over PT and OT sessions at discharge). Wilcoxon-signed rank tests revealed that most repetition variables did not change significantly over the inpatient rehabilitation stay. In contrast, clinical outcomes for the arm and leg improved over this time period. Repetitions of upper- and lower-extremity movements are markedly low during PT and OT sessions. Despite improvements in clinical outcomes, there was no significant increase in movement repetitions over the course of inpatient rehabilitation stay.

  16. Clinical application of gradient echo sequences with prolonged repetition times

    Energy Technology Data Exchange (ETDEWEB)

    Tiling, R.; Fink, U.; Deimling, M.; Bauer, W.M.; Yousry, T.; Krauss, B.

    1988-09-01

    Studies designed to optimise image contrasts of gradient echo sequences showed, that especially repetition times between 250 and 500 ms in combination with adequate echo times and flip angles provide new image contrasts. The clinical purpose of gradient echo sequences with longer TR was systematically evaluated in 450 patients. A major advantage of GE sequences was the low signal intensity of fat and bone tissue. On the other hand differnt pathologic changes showed a high signal intensity in comparison to T/sub 2/ weighted spin echo sequences as well. With the possibility of multiple slices GE sequences were of outstanding diagnostic value especially in MR of soft tissue and of the musculoskeletal system. T/sub 2/ weighted SE sequences provided no additional informations and could therefore be omitted in a great number of examinations.

  17. Repetitive Bunches from RF-Photo Gun Radiate Coherently

    CERN Document Server

    Van der Geer, C A J; Van der Geer, S B

    2004-01-01

    We consider to feed the laser wake field accelerator of the alpha-X project by a train of low charge pancake electron bunches to reduce undesired expansion due to space-charge forces. To this purpose the photo excitation laser of the rf-injector is split into a train of sub-pulses, such that each of the produced electron bunches falls into a successive ponderomotive well of the plasma accelerator. This way the total accelerated charge is not reduced. The repetitive photo gun can be tested, at low energy, by connecting it directly to the undulator and monitoring the radiation. The assertions are based on the results of new GPT simulations.

  18. Distribution of repetitions of ancestors in genealogical trees

    Science.gov (United States)

    Derrida, Bernard; Manrubia, Susanna C.; Zanette, Damián H.

    2000-06-01

    We calculate the probability distribution of repetitions of ancestors in a genealogical tree for simple neutral models of a closed population with sexual reproduction and non-overlapping generations. Each ancestor at generation g in the past has a weight w which is (up to a normalization) the number of times this ancestor appears in the genealogical tree of an individual at present. The distribution Pg( w) of these weights reaches a stationary shape P∞( w), for large g, i.e., for a large number of generations back in the past. For small w, P ∞(w) is a power law ( P∞( w)∼ wβ), with a non-trivial exponent β which can be computed exactly using a standard procedure of the renormalization group approach. Some extensions of the model are discussed and the effect of these variants on the shape of P∞( w) are analysed.

  19. RN-BSN curricula: designed for transition, not repetition.

    Science.gov (United States)

    Allen, Patricia E; Armstrong, Myrna L

    2013-01-01

    Combined efforts of professional mandates, employer preferences for increased educational levels of staff registered nurses (RNs), Magnet's higher environmental ratings, the Institute of Medicine report, and Aiken's (2003, 2008, & 2011) clinical research outcomes have spawn renewed attention for RN-baccalaureate degree of science in nursing (BSN) education. Yet, nationally, only 21.6% of associate degree nurses are continuing their education (Health Resources and Services Administration, 2010). Designing programs with the student as the center, where student/faculty engagement is the goal, has enabled one school of nursing to develop a quality on-line RN-to-BSN program. Core values of the program reveal a faculty who is committed to development of education to transition the associate degree and/or diploma graduate to professional nursing practice without repetition of content and learning activities.

  20. Repetition blindness for natural images of objects with viewpoint changes

    Directory of Open Access Journals (Sweden)

    Stephane eBuffat

    2013-01-01

    Full Text Available When stimuli are repeated in a rapid serial visual presentation (RSVP, observers sometimes fail to report the second occurrence of a target. This phenomenon is referred to as repetition blindness (RB. We report an RSVP experiment with photographs in which we manipulated object viewpoints between the first and second occurrences of a target (0-, 45-, or 90-degree changes, and spatial frequency content. Natural images were spatially filtered to produce low, medium, or high spatial-frequency stimuli. RB was observed for all filtering conditions. Surprisingly, for full-spectrum images, RB increased significantly as the viewpoint reached 90 degrees. For filtered images, a similar pattern of results was found for all conditions except for medium spatial-frequency stimuli. These findings suggest that object recognition in RSVP are subtended by viewpoint-specific representations for all spatial frequencies except medium ones.

  1. Simple filtered repetitively pulsed vacuum arc plasma source

    Science.gov (United States)

    Chekh, Yu.; Zhirkov, I. S.; Delplancke-Ogletree, M. P.

    2010-02-01

    A very simple design of cathodic filtered vacuum arc plasma source is proposed. The source without filter has only four components and none of them require precise machining. The source operates in a repetitively pulsed regime, and for laboratory experiments it can be used without water cooling. Despite the simple construction, the source provides high ion current at the filter outlet reaching 2.5% of 400 A arc current, revealing stable operation in a wide pressure range from high vacuum to oxygen pressure up to more than 10-2 mbar. There is no need in complicated power supply system for this plasma source, only one power supply can be used to ignite the arc, to provide the current for the arc itself, to generate the magnetic field in the filter, and provide its positive electric biasing without any additional high power resistance.

  2. Resistive Wall Heating of the Undulator in High Repetition Rate

    Energy Technology Data Exchange (ETDEWEB)

    Qiang, J; Corlett, J; Emma, P; Wu, J

    2012-05-20

    In next generation high repetition rate FELs, beam energy loss due to resistive wall wakefields will produce significant amount of heat. The heat load for a superconducting undulator (operating at low temperature), must be removed and will be expensive to remove. In this paper, we study this effect in an undulator proposed for a Next Generation Light Source (NGLS) at LBNL. We benchmark our calculations with measurements at the LCLS and carry out detailed parameter studies using beam from a start-to-end simulation. Our preliminarym results suggest that the heat load in the undulator is about 2 W/m or lower with an aperture size of 6 mm for nominal NGLS preliminary design parameters.

  3. A high repetition rate XUV seeding source for FLASH2

    Energy Technology Data Exchange (ETDEWEB)

    Willner, Arik

    2012-05-15

    Improved performance of free-electron laser (FEL) light sources in terms of timing stability, pulse shape and spectral properties of the amplified FEL pulses is of interest in material science, the fields of ultrafast dynamics, biology, chemistry and even special branches in industry. A promising scheme for such an improvement is direct seeding with high harmonic generation (HHG) in a noble gas target. A free-electron laser seeded by an external extreme ultraviolet (XUV) source is planned for FLASH2 at DESY in Hamburg. The requirements for the XUV/soft X-ray source can be summarized as follows: A repetition rate of at least 100 kHz in a 10 Hz burst is needed at variable wavelengths from 10 to 40 nm and pulse energies of several nJ within a single laser harmonic. This application requires a laser amplifier system with exceptional parameters, mJ-level pulse energy, 10-15 fs pulse duration at 100 kHz (1 MHz) burst repetition rate. A new optical parametric chirped-pulse amplification (OPCPA) system is under development in order to meet these requirements, and very promising results have been achieved in the last three years. In parallel to this development, a new HHG concept is necessary to sustain high average power of the driving laser system and to generate harmonics with high conversion efficiencies. Currently, the highest conversion efficiency with HHG has been demonstrated using gas-filled capillary targets. For our application, only a free-jet target can be used for HHG, in order to overcome damage threshold limitations of HHG target optics at a high repetition rate. A novel dual-gas multijet gas target has been developed and first experiments show remarkable control of the degree of phase matching forming the basis for improved control of the harmonic photon flux and the XUV pulse characteristics. The basic idea behind the dual-gas concept is the insertion of matching zones in between multiple HHG sources. These matching sections are filled with hydrogen which

  4. Intrinsic and extrinsic motivation for stereotypic and repetitive behavior.

    Science.gov (United States)

    Joosten, Annette V; Bundy, Anita C; Einfeld, Stewart L

    2009-03-01

    This study provides evidence for intrinsic and extrinsic motivators for stereotypical and repetitive behavior in children with autism and intellectual disability and children with intellectual disability alone. We modified the Motivation Assessment Scale (MAS) (1988b); dividing it into intrinsic and extrinsic measures and adding items to assess anxiety as an intrinsic motivator. Rasch analysis of data from 279 MASs (74 children) revealed that the items formed two unidimensional scales. Anxiety was a more likely intrinsic motivator than sensory seeking for children with dual diagnoses; the reverse was true for children with intellectual disability only. Escape and gaining a tangible object were the most common extrinsic motivators for those with dual diagnoses and attention and escape for children with intellectual disability.

  5. Pancreatic Cancer: 80 Years of Surgery—Percentage and Repetitions

    Directory of Open Access Journals (Sweden)

    Birgir Gudjonsson

    2016-01-01

    Full Text Available Objective. The incidence of pancreatic cancer is estimated to be 48,960 in 2015 in the US and projected to become the second and third leading causes of cancer-related deaths by 2030. The mean costs in 2015 may be assumed to be $79,800 per patient and for each resection $164,100. Attempt is made to evaluate the results over the last 80 years, the number of survivors, and the overall survival percentage. Methods. Altogether 1230 papers have been found which deal with resections and reveal survival information. Only 621 of these report 5-year survivors. Reservation about surgery was first expressed in 1964 and five-year survival of nonresected survivors is well documented. Results. The survival percentage depends not only on the number of survivors but also on the subset from which it is calculated. Since the 1980s the papers have mainly reported the number of resections and survival as actuarial percentages, with or without the actual number of survivors being reported. The actuarial percentage is on average 2.75 higher. Detailed information on the original group (TN, number of resections, and actual number of survivors is reported in only 10.6% of the papers. Repetition occurs when the patients from a certain year are reported several times from the same institution or include survivors from many institutions or countries. Each 5-year survivor may be reported several times. Conclusion. Assuming a 10% resection rate and correcting for repetitions and the life table percentage the overall actual survival rate is hardly more than 0.3%.

  6. Repetition priming in selective attention: A TVA analysis.

    Science.gov (United States)

    Ásgeirsson, Árni Gunnar; Kristjánsson, Árni; Bundesen, Claus

    2015-09-01

    Current behavior is influenced by events in the recent past. In visual attention, this is expressed in many variations of priming effects. Here, we investigate color priming in a brief exposure digit-recognition task. Observers performed a masked odd-one-out singleton recognition task where the target-color either repeated or changed between subsequent trials. Performance was measured by recognition accuracy over exposure durations. The purpose of the study was to replicate earlier findings of perceptual priming in brief displays and to model those results based on a Theory of Visual Attention (TVA; Bundesen, 1990). We tested 4 different definitions of a generic TVA-model and assessed their explanatory power. Our hypothesis was that priming effects could be explained by selective mechanisms, and that target-color repetitions would only affect the selectivity parameter (α) of our models. Repeating target colors enhanced performance for all 12 observers. As predicted, this was only true under conditions that required selection of a target among distractors, but not when a target was presented alone. Model fits by TVA were obtained with a trial-by-trial maximum likelihood estimation procedure that estimated 4-15 free parameters, depending on the particular model. We draw two main conclusions. Color priming can be modeled simply as a change in selectivity between conditions of repetition or swap of target color. Depending on the desired resolution of analysis; priming can accurately be modeled by a simple four parameter model, where VSTM capacity and spatial biases of attention are ignored, or more fine-grained by a 10 parameter model that takes these aspects into account. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Dissecting the functional anatomy of auditory word repetition

    Directory of Open Access Journals (Sweden)

    Thomas Matthew Hadley Hope

    2014-05-01

    Full Text Available Auditory word repetition involves many different brain regions, whose functions are still far from fully understood. Here, we use a single, multi-factorial, within-subjects fMRI design to identify those regions, and to functionally distinguish the multiple linguistic and non-linguistic processing areas that are all involved in repeating back heard words. The study compared: (1 auditory to visual inputs; (2 phonological to non-phonological inputs; (3 semantic to non-semantic inputs; and (4 speech production to finger-press responses. The stimuli included words (semantic and phonological inputs, pseudowords (phonological input, pictures and sounds of animals or objects (semantic input, and coloured patterns and hums (non-semantic and non-phonological. The speech production tasks involved auditory repetition, reading and naming while the finger press tasks involved one-back matching.The results from the main effects and interactions were compared to predictions from a previously reported functional anatomical model of language based on a meta-analysis of many different neuroimaging experiments. Although many findings from the current experiment replicated those predicted, our within-subject design also revealed novel results by providing sufficient anatomical precision to distinguish several different regions within: (1 the anterior insula (a dorsal region involved in both covert and overt speech production, and a more ventral region involved in overt speech only; (2 the pars orbitalis (with distinct sub-regions responding to phonological and semantic processing; (3 the anterior cingulate and SMA (whose subregions show differential sensitivity to speech and finger press responses; and (4 the cerebellum (with distinct regions for semantic processing, speech production and domain general processing. We also dissociated four different types of phonological effects in, respectively, the left superior temporal sulcus, left putamen, left ventral premoto

  8. Repetitive Pediatric Anesthesia in a Non-Hospital Setting

    Energy Technology Data Exchange (ETDEWEB)

    Buchsbaum, Jeffrey C., E-mail: jbuchsba@iupui.edu [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, Indiana (United States); Indiana University Health Proton Therapy Center, Bloomington, Indiana (United States); McMullen, Kevin P.; Douglas, James G. [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, Indiana (United States); Indiana University Health Proton Therapy Center, Bloomington, Indiana (United States); Jackson, Jeffrey L.; Simoneaux, R. Victor; Hines, Matthew; Bratton, Jennifer; Kerstiens, John [Indiana University Health Proton Therapy Center, Bloomington, Indiana (United States); Johnstone, Peter A.S. [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, Indiana (United States); Indiana University Health Proton Therapy Center, Bloomington, Indiana (United States)

    2013-04-01

    Purpose: Repetitive sedation/anesthesia (S/A) for children receiving fractionated radiation therapy requires induction and recovery daily for several weeks. In the vast majority of cases, this is accomplished in an academic center with direct access to pediatric faculty and facilities in case of an emergency. Proton radiation therapy centers are more frequently free-standing facilities at some distance from specialized pediatric care. This poses a potential dilemma in the case of children requiring anesthesia. Methods and Materials: The records of the Indiana University Health Proton Therapy Center were reviewed for patients requiring anesthesia during proton beam therapy (PBT) between June 1, 2008, and April 12, 2012. Results: A total of 138 children received daily anesthesia during this period. A median of 30 fractions (range, 1-49) was delivered over a median of 43 days (range, 1-74) for a total of 4045 sedation/anesthesia procedures. Three events (0.0074%) occurred, 1 fall from a gurney during anesthesia recovery and 2 aspiration events requiring emergency department evaluation. All 3 children did well. One aspiration patient needed admission to the hospital and mechanical ventilation support. The other patient returned the next day for treatment without issue. The patient who fell was not injured. No patient required cessation of therapy. Conclusions: This is the largest reported series of repetitive pediatric anesthesia in radiation therapy, and the only available data from the proton environment. Strict adherence to rigorous protocols and a well-trained team can safely deliver daily sedation/anesthesia in free-standing proton centers.

  9. Characterization of IS6110 insertions in the dnaA-dnaN intergenic region of Mycobacterium tuberculosis clinical isolates.

    Science.gov (United States)

    Turcios, L; Casart, Y; Florez, I; de Waard, J; Salazar, L

    2009-02-01

    Mycobacterium tuberculosis isolates with identical IS6110 restriction fragment length polymorphism (RFLP) patterns are considered to be clonally related. The presence of IS6110 in the dnaA-dnaN intergenic region, one preferential locus for the integration of IS6110, was evaluated in 125 M. tuberculosis isolates. Five isolates had IS6110 inserted in this region, and two consisted of a mix of isogenic strains that putatively have evolved during a single infection. Strains from the same isolate had identical spoligo and mycobacterial interspersed repetitive unit-variable-number tandem repeat profiles, but had slight variations in IS6110 RFLP patterns, due to the presence of IS6110 in the dnaA-dnaN intergenic region. Duplication of the dnaA-dnaN intergenic region was found in one isogenic strain.

  10. Hemispheric Asymmetries in Repetition Enhancement and Suppression Effects in the Newborn Brain.

    Directory of Open Access Journals (Sweden)

    Camillia Bouchon

    Full Text Available The repeated presentation of stimuli typically attenuates neural responses (repetition suppression or, less commonly, increases them (repetition enhancement when stimuli are highly complex, degraded or presented under noisy conditions. In adult functional neuroimaging research, these repetition effects are considered as neural correlates of habituation. The development and respective functional significance of these effects in infancy remain largely unknown.This study investigates repetition effects in newborns using functional near-infrared spectroscopy, and specifically the role of stimulus complexity in evoking a repetition enhancement vs. a repetition suppression response, following up on Gervain et al. (2008. In that study, abstract rule-learning was found at birth in cortical areas specific to speech processing, as evidenced by a left-lateralized repetition enhancement of the hemodynamic response to highly variable speech sequences conforming to a repetition-based ABB artificial grammar, but not to a random ABC grammar.Here, the same paradigm was used to investigate how simpler stimuli (12 different sequences per condition as opposed to 140, and simpler presentation conditions (blocked rather than interleaved would influence repetition effects at birth.Results revealed that the two grammars elicited different dynamics in the two hemispheres. In left fronto-temporal areas, we reproduce the early perceptual discrimination of the two grammars, with ABB giving rise to a greater response at the beginning of the experiment than ABC. In addition, the ABC grammar evoked a repetition enhancement effect over time, whereas a stable response was found for the ABB grammar. Right fronto-temporal areas showed neither initial discrimination, nor change over time to either pattern.Taken together with Gervain et al. (2008, this is the first evidence that manipulating methodological factors influences the presence or absence of neural repetition enhancement

  11. [Heterogeneity and homologies of the repeating and unique DNA of dragonflies (Odonata, Insecta)].

    Science.gov (United States)

    Petrov, N B; Aleshin, V V

    1983-01-01

    A relative content of unique and reiterated nucleotide sequences in DNA of eleven dragonfly species was estimated. The degree of intra- and intergenomic divergence of these DNA sequences was determined by means of DNA-DNA hybridization. Species from different genera share 40-45% of the repetitive sequences and those from different families--from 11 to 20% only. Data on the thermostability of homo- and heteroduplexes suggest that new families of the repetitive sequences have arisen repeatedly during dragonflies evolution. The quality of homologous unique sequences in the DNA compared (20-97%) correlates with the taxonomic relationships of species. Phylogenesis of some dragonfly families is discussed in view of the results obtained.

  12. Correlation of DNA methylation levels in blood and saliva DNA in young girls of the LEGACY Girls study.

    Science.gov (United States)

    Wu, Hui-Chen; Wang, Qiao; Chung, Wendy K; Andrulis, Irene L; Daly, Mary B; John, Esther M; Keegan, Theresa H M; Knight, Julia; Bradbury, Angela R; Kappil, Maya A; Gurvich, Irina; Santella, Regina M; Terry, Mary Beth

    2014-07-01

    Many epidemiologic studies of environmental exposures and disease susceptibility measure DNA methylation in white blood cells (WBC). Some studies are also starting to use saliva DNA as it is usually more readily available in large epidemiologic studies. However, little is known about the correlation of methylation between WBC and saliva DNA. We examined DNA methylation in three repetitive elements, Sat2, Alu, and LINE-1, and in four CpG sites, including AHRR (cg23576855, cg05575921), cg05951221 at 2q37.1, and cg11924019 at CYP1A1, in 57 girls aged 6-15 years with blood and saliva collected on the same day. We measured all DNA methylation markers by bisulfite-pyrosequencing, except for Sat2 and Alu, which were measured by the MethyLight assay. Methylation levels measured in saliva DNA were lower than those in WBC DNA, with differences ranging from 2.8% for Alu to 14.1% for cg05575921. Methylation levels for the three repetitive elements measured in saliva DNA were all positively correlated with those in WBC DNA. However, there was a wide range in the Spearman correlations, with the smallest correlation found for Alu (0.24) and the strongest correlation found for LINE-1 (0.73). Spearman correlations for cg05575921, cg05951221, and cg11924019 were 0.33, 0.42, and 0.79, respectively. If these findings are replicated in larger studies, they suggest that, for selected methylation markers (e.g., LINE-1), methylation levels may be highly correlated between blood and saliva, while for others methylation markers, the levels may be more tissue specific. Thus, in studies that differ by DNA source, each interrogated site should be separately examined in order to evaluate the correlation in DNA methylation levels across DNA sources.

  13. The effects of high resistance-few repetitions and low resistance-high repetitions resistance training on climbing performance.

    Science.gov (United States)

    Hermans, Espen; Andersen, Vidar; Saeterbakken, Atle Hole

    2017-05-01

    The aim of the study was to compare the effects of different strength training intensities on climbing performance, climbing-specific tests and a general strength test. Thirty lower grade and intermediate-level climbers participated in a 10-week training programme. The participants were randomized into three groups: high resistance-few repetitions training groups (HR-FR), low resistance-high repetitions training groups (LR-HR) and a control group (CON) which continued climbing/training as usual. Post-testing results demonstrated statistical tendencies for climbing performance improvements in the HR-FR and LR-HR (p = 0.088-0.090, effect size = 0.55-0.73), but no differences were observed between the groups (p = 0.950). For the climbing-specific tests, no differences were observed between the groups (p = 0.507-1.000), but the HR-FR and LR-HR improved their time in both Dead-hang (p = 0.004-0.026) and Bent-arm hang (p training groups reduced their climbing sessions during the intervention compared to the CON group (p = 0.057-0.074). In conclusion, HR-FR and LR-HR training programmes demonstrated an 11% and 12% non-significant improvement in climbing performance despite a 50% reduction in climbing sessions, but improved the results in strength and climbing-specific tests. None of the training intensities was superior compared to the others.

  14. Molecular genotyping of Colletotrichum species based on arbitrarily primed PCR, A + T-Rich DNA, and nuclear DNA analyses

    Science.gov (United States)

    Freeman, S.; Pham, M.; Rodriguez, R.J.

    1993-01-01

    Molecular genotyping of Colletotrichum species based on arbitrarily primed PCR, A + T-rich DNA, and nuclear DNA analyses. Experimental Mycology 17, 309-322. Isolates of Colletotrichum were grouped into 10 separate species based on arbitrarily primed PCR (ap-PCR), A + T-rich DNA (AT-DNA) and nuclear DNA banding patterns. In general, the grouping of Colletotrichum isolates by these molecular approaches corresponded to that done by classical taxonomic identification, however, some exceptions were observed. PCR amplification of genomic DNA using four different primers allowed for reliable differentiation between isolates of the 10 species. HaeIII digestion patterns of AT-DNA also distinguished between species of Colletotrichum by generating species-specific band patterns. In addition, hybridization of the repetitive DNA element (GcpR1) to genomic DNA identified a unique set of Pst 1-digested nuclear DNA fragments in each of the 10 species of Colletotrichum tested. Multiple isolates of C. acutatum, C. coccodes, C. fragariae, C. lindemuthianum, C. magna, C. orbiculare, C. graminicola from maize, and C. graminicola from sorghum showed 86-100% intraspecies similarity based on ap-PCR and AT-DNA analyses. Interspecies similarity determined by ap-PCR and AT-DNA analyses varied between 0 and 33%. Three distinct banding patterns were detected in isolates of C. gloeosporioides from strawberry. Similarly, three different banding patterns were observed among isolates of C. musae from diseased banana.

  15. DNA data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Raw DNA chromatogram data produced by the ABI 373, 377, 3130 and 3730 automated sequencing machines in ABI format. These are from fish (primarily Sebastes spp.,...

  16. Selective binding of specific mouse genomic DNA fragments by mouse vimentin filaments in vitro.

    Science.gov (United States)

    Wang, X; Tolstonog, G; Shoeman, R L; Traub, P

    1996-03-01

    Mouse vimentin intermediate filaments (IFs) reconstituted in vitro were analyzed for their capacity to select certain DNA sequences from a mixture of about 500-bp-long fragments of total mouse genomic DNA. The fragments preferentially bound by the IFs and enriched by several cycles of affinity binding and polymerase chain reaction (PCR) amplification were cloned and sequenced. In general, they were G-rich and highly repetitive in that they often contained Gn, (GT)n, and (GA)n repeat elements. Other, more complex repeat sequences were identified as well. Apart from the capacity to adopt a Z-DNA and triple helix configuration under superhelical tension, many fragments were potentially able to form cruciform structures and contained consensus binding sites for various transcription factors. All of these sequence elements are known to occur in introns and 5'/3'-flanking regions of genes and to play roles in DNA transcription, recombination and replication. A FASTA search of the EMBL data bank indeed revealed that sequences homologous to the mouse repetitive DNA fragments are commonly associated with gene-regulatory elements. Unexpectedly, vimentin IFs also bound a large number of apparently overlapping, AT-rich DNA fragments that could be aligned into a composite sequence highly homologous to the 234-bp consensus centromere repeat sequence of gamma-satellite DNA. Previous experiments have shown a high affinity of vimentin for G-rich, repetitive telomere DNA sequences, superhelical DNA, and core histones. Taken together, these data support the hypothesis that, after penetration of the double nuclear membrane via an as yet unidentified mechanism, vimentin IFs cooperatively fix repetitive DNA sequence elements in a differentiation-specific manner in the nuclear periphery subjacent to the nuclear lamina and thus participate in the organization of chromatin and in the control of transcription, replication, and recombination processes. This includes aspects of global

  17. The Action Plan Against Repetitive Work - An Industrial Relation Strategy for Improving the Working Environment

    DEFF Research Database (Denmark)

    Hasle, Peter; Møller, Niels

    2001-01-01

    The Danish Action Plan against Repetitive Work is presented and discussed as a possible new strategy for regulating repetitive work as well as other complicated working environment problems. The article is based on an empirical evaluation ot the Action Plan. The asseessment of the Action Plan ind...... and industrial relation agreements can be used to regulate other working environment problems....

  18. Nonword Repetition and Phoneme Elision in Adults Who Do and Do Not Stutter

    Science.gov (United States)

    Byrd, Courtney T.; Vallely, Megann; Anderson, Julie D.; Sussman, Harvey

    2012-01-01

    The purpose of the present study was to explore the phonological working memory of adults who stutter through the use of a non-word repetition and a phoneme elision task. Participants were 14 adults who stutter (M = 28 years) and 14 age/gender matched adults who do not stutter (M = 28 years). For the non-word repetition task, the participants had…

  19. The Function of Repeating: The Relation between Word Class and Repetition Type in Developmental Stuttering

    Science.gov (United States)

    Buhr, Anthony P.; Jones, Robin M.; Conture, Edward G.; Kelly, Ellen M.

    2016-01-01

    Background: It is already known that preschool-age children who stutter (CWS) tend to stutter on function words at the beginning of sentences. It is also known that phonological errors potentially resulting in part-word repetitions tend to occur on content words. However, the precise relation between word class and repetition type in preschool-age…

  20. On the Road to Science Literacy: Building Confidence and Competency in Technical Language through Choral Repetition

    Science.gov (United States)

    Hohenshell, Liesl M.; Woller, Michael J.; Sherlock, Wallace

    2013-01-01

    In order to be successful, students must acquire the language of science for both oral and written communication. In this article we examine an oral language learning technique called choral repetition for its role in building literacy in the context of an animal physiology course. For 3 weeks, the instructor conducted choral repetitions of nine…

  1. Functional dissociations in top-down control dependent neural repetition priming.

    NARCIS (Netherlands)

    Klaver, P.; Schnaidt, M.; Fell, J.; Ruhlmann, J.; Elger, C.E.; Fernandez, G.

    2007-01-01

    Little is known about the neural mechanisms underlying top-down control of repetition priming. Here, we use functional brain imaging to investigate these mechanisms. Study and repetition tasks used a natural/man-made forced choice task. In the study phase subjects were required to respond to either

  2. Task Repetition Effects on L1 Use in EFL Child Task-Based Interaction

    Science.gov (United States)

    Azkarai, Agurtzane; García Mayo, María del Pilar

    2017-01-01

    Research has shown that tasks provide second language (L2) learners with many opportunities to learn the L2. Task repetition has been claimed to benefit L2 learning since familiarity with procedure and/or content gives learners the chance to focus on more specific aspects of language. Most research on task repetition has focused on adult…

  3. Repetition suppression and expectation suppression are dissociable in time in early auditory evoked fields.

    Science.gov (United States)

    Todorovic, Ana; de Lange, Floris P

    2012-09-26

    Repetition of a stimulus, as well as valid expectation that a stimulus will occur, both attenuate the neural response to it. These effects, repetition suppression and expectation suppression, are typically confounded in paradigms in which the nonrepeated stimulus is also relatively rare (e.g., in oddball blocks of mismatch negativity paradigms, or in repetition suppression paradigms with multiple repetitions before an alternation). However, recent hierarchical models of sensory processing inspire the hypothesis that the two might be separable in time, with repetition suppression occurring earlier, as a consequence of local transition probabilities, and suppression by expectation occurring later, as a consequence of learnt statistical regularities. Here we test this hypothesis in an auditory experiment by orthogonally manipulating stimulus repetition and stimulus expectation and, using magnetoencephalography, measuring the neural response over time in human subjects. We found that stimulus repetition (but not stimulus expectation) attenuates the early auditory response (40-60 ms), while stimulus expectation (but not stimulus repetition) attenuates the subsequent, intermediate stage of auditory processing (100-200 ms). These findings are well in line with hierarchical predictive coding models, which posit sequential stages of prediction error resolution, contingent on the level at which the hypothesis is generated.

  4. Subcategories of Restricted and Repetitive Behaviors in Children with Autism Spectrum Disorders

    Science.gov (United States)

    Bishop, Somer L.; Hus, Vanessa; Duncan, Amie; Huerta, Marisela; Gotham, Katherine; Pickles, Andrew; Kreiger, Abba; Buja, Andreas; Lund, Sabata; Lord, Catherine

    2013-01-01

    Research suggests that restricted and repetitive behaviors (RRBs) can be subdivided into Repetitive Sensory Motor (RSM) and Insistence on Sameness (IS) behaviors. However, because the majority of previous studies have used the Autism Diagnostic Interview-Revised (ADI-R), it is not clear whether these subcategories reflect the actual organization…

  5. Measuring Repetitive Behaviors as a Treatment Endpoint in Youth with Autism Spectrum Disorder

    Science.gov (United States)

    Scahill, Lawrence; Aman, Michael G.; Lecavalier, Luc; Halladay, Alycia K.; Bishop, Somer L.; Bodfish, James W.; Grondhuis, Sabrina; Jones, Nancy; Horrigan, Joseph P.; Cook, Edwin H.; Handen, Benjamin L.; King, Bryan H.; Pearson, Deborah A.; McCracken, James T.; Sullivan, Katherine Anne; Dawson, Geraldine

    2015-01-01

    Restricted interests and repetitive behaviors vary widely in type, frequency, and intensity among children and adolescents with autism spectrum disorder. They can be stigmatizing and interfere with more constructive activities. Accordingly, restricted interests and repetitive behaviors may be a target of intervention. Several standardized…

  6. Brief Report: Repetitive Behaviours in Greek Individuals with Autism Spectrum Disorder

    Science.gov (United States)

    Georgiades, Stelios; Papageorgiou, Vaya; Anagnostou, Evdokia

    2010-01-01

    The main objective of this study was to examine the factor structure of restricted repetitive behaviours (RRBs) in a sample of 205 Greek individuals with Autism Spectrum Disorder (ASD), using the Repetitive Behavior Scale-Revised (RBS-R). Results show that the structure of RRBs in this Greek sample can be described using a 2-factor solution. The…

  7. The Repetitive Behavior Scale-Revised: Independent Validation in Individuals with Autism Spectrum Disorders

    Science.gov (United States)

    Lam, Kristen S. L.; Aman, Michael G.

    2007-01-01

    A key feature of autism is restricted repetitive behavior (RRB). Despite the significance of RRBs, little is known about their phenomenology, assessment, and treatment. The Repetitive Behavior Scale-Revised (RBS-R) is a recently-developed questionnaire that captures the breadth of RRB in autism. To validate the RBS-R in an independent sample, we…

  8. Motor Control and Nonword Repetition in Specific Working Memory Impairment and SLI

    Science.gov (United States)

    Archibald, Lisa M. D.; Joanisse, Marc F.; Munson, Benjamin

    2013-01-01

    Purpose: Debate around the underlying cognitive factors leading to poor performance in the repetition of nonwords by children with developmental impairments in language has centered around phonological short-term memory, lexical knowledge, and other factors. This study examines the impact of motor control demands on nonword repetition in groups of…

  9. Repetition rate continuously tunable 10-GHz picosecond mode-locked fiber ring laser

    Institute of Scientific and Technical Information of China (English)

    Fang Wan; Ziyu Wang

    2006-01-01

    A couple of simple-structure phase modulators were used in active mode-locked fiber laser to implement repetition rate continuous tuning. The laser produces pulse as short as 5.7 ps whose repetition rate tuning can cover the spacing of the adjoining order mode-locking frequencies.

  10. Frequency Adaptive Repetitive Control of Grid-Tied Three-Phase PV Inverters

    DEFF Research Database (Denmark)

    Zhou, Keliang; Yang, Yongheng; Blaabjerg, Frede

    2016-01-01

    Repetitive control offers an accurate current control scheme for grid-tied converters to feed high quality sinusoidal current into the grid. However, with grid frequency being treated as a constant value, conventional repetitive controller fail to produce high quality feeding current...

  11. Motor Control and Nonword Repetition in Specific Working Memory Impairment and SLI

    Science.gov (United States)

    Archibald, Lisa M. D.; Joanisse, Marc F.; Munson, Benjamin

    2013-01-01

    Purpose: Debate around the underlying cognitive factors leading to poor performance in the repetition of nonwords by children with developmental impairments in language has centered around phonological short-term memory, lexical knowledge, and other factors. This study examines the impact of motor control demands on nonword repetition in groups of…

  12. Topic Repetitiveness after Traumatic Brain Injury: An Emergent, Jointly Managed Behaviour

    Science.gov (United States)

    Body, Richard; Parker, Mark

    2005-01-01

    Topic repetitiveness is a common component of pragmatic impairment and a powerful contributor to social exclusion. Despite this, description, characterization and intervention remain underdeveloped. This article explores the nature of repetitiveness in traumatic brain injury (TBI). A case study of one individual after TBI provides the basis for a…

  13. Changes of the Prefrontal EEG (Electroencephalogram) Activities According to the Repetition of Audio-Visual Learning.

    Science.gov (United States)

    Kim, Yong-Jin; Chang, Nam-Kee

    2001-01-01

    Investigates the changes of neuronal response according to a four time repetition of audio-visual learning. Obtains EEG data from the prefrontal (Fp1, Fp2) lobe from 20 subjects at the 8th grade level. Concludes that the habituation of neuronal response shows up in repetitive audio-visual learning and brain hemisphericity can be changed by…

  14. On the Road to Science Literacy: Building Confidence and Competency in Technical Language through Choral Repetition

    Science.gov (United States)

    Hohenshell, Liesl M.; Woller, Michael J.; Sherlock, Wallace

    2013-01-01

    In order to be successful, students must acquire the language of science for both oral and written communication. In this article we examine an oral language learning technique called choral repetition for its role in building literacy in the context of an animal physiology course. For 3 weeks, the instructor conducted choral repetitions of nine…

  15. The use of digit and sentence repetition in the identification of ...

    African Journals Online (AJOL)

    Kate H

    be more sensitive than others for the difference between the performance of the ... assessment instruments, screening tools that employ repetition tasks can be ... Whilst “specific language impairment” is widely used in academic or ... Digit repetition requires a person to repeat in the correct order a series of digits presented.

  16. High-repetition-rate XeCl waveguide laser without gas flow

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, C.P.; Gordon C. III; Moutoulas, C.; Feldman, B.J.

    1987-03-01

    Operation of a microwave discharge XeCl laser at pulse-repetition rates extending to 8 kHz without flow of the laser gas is reported. Present limits on pulse-repetition rate appear to be imposed by thermally induced refractive-index gradients.

  17. The Relationship between Anxiety and Repetitive Behaviours in Autism Spectrum Disorder

    Science.gov (United States)

    Rodgers, J.; Glod, M.; Connolly, B.; McConachie, H.

    2012-01-01

    Children with Autism Spectrum Disorder are vulnerable to anxiety. Repetitive behaviours are a core feature of Autism Spectrum Disorder (ASD) and have been associated with anxiety. This study examined repetitive behaviours and anxiety in two groups of children with autism spectrum disorder, those with high anxiety and those with lower levels of…

  18. Randomization of Symbol Repetition of Punch Cards with Superimposed Coding in Information-Search Systems.

    Science.gov (United States)

    Pirovich, L. Ya

    The article shows the effect of the irregularity of using separate symbols on search noise on punch cards with superimposed symbol coding in information-search system (IPS). A binomial law of random value distribution of repetition of each symbol is established and analyzed. A method of determining the maximum value of symbol repetition is…

  19. DNA adductomics.

    Science.gov (United States)

    Balbo, Silvia; Turesky, Robert J; Villalta, Peter W

    2014-03-17

    Systems toxicology is a broad-based approach to describe many of the toxicological features that occur within a living system under stress or subjected to exogenous or endogenous exposures. The ultimate goal is to capture an overview of all exposures and the ensuing biological responses of the body. The term exposome has been employed to refer to the totality of all exposures, and systems toxicology investigates how the exposome influences health effects and consequences of exposures over a lifetime. The tools to advance systems toxicology include high-throughput transcriptomics, proteomics, metabolomics, and adductomics, which is still in its infancy. A well-established methodology for the comprehensive measurement of DNA damage resulting from every day exposures is not fully developed. During the past several decades, the (32)P-postlabeling technique has been employed to screen the damage to DNA induced by multiple classes of genotoxicants; however, more robust, specific, and quantitative methods have been sought to identify and quantify DNA adducts. Although triple quadrupole and ion trap mass spectrometry, particularly when using multistage scanning (LC-MS(n)), have shown promise in the field of DNA adductomics, it is anticipated that high-resolution and accurate-mass LC-MS(n) instrumentation will play a major role in assessing global DNA damage. Targeted adductomics should also benefit greatly from improved triple quadrupole technology. Once the analytical MS methods are fully mature, DNA adductomics along with other -omics tools will contribute greatly to the field of systems toxicology.

  20. Construction of Agropyrum intermedium 2Ai-2 Chromosome DNA Library and Cloning of Species-Specific DNA Sequences

    Institute of Scientific and Technical Information of China (English)

    HE Cong-fen; MA You-zhi; XIN Zhi-yong; XU Qiong-fang; LI Lian-cheng

    2004-01-01

    The univalent from the meiosis-metaphase spreads of F1 (Z2× wheat variety Wan7107) was identified to be Agropyrum intermedium 2Ai-2 chromosome by GISH. The 2Ai-2 chromosomes were microisolated and collected. After two rounds of PCR amplification, the PCR products were ranged from 150 - 3 000 bp,with predominant fragments at about 200 - 2 000 bp. Using Ag.intermediumgenomic DNA as a probe, Southern blotting analysis confirmed the products originated from Ag. intermediumgenome. The products were purified, ligated to pUC18 and then transformed into competence E.coli DH5α to produce a 2Ai-2 chromosome DNA library. The microcloning experiments produced approximately 5×105 clones, the size range of the cloned inserts was 200- 1 500 bp, with an average of 580bp. Using Ag. intermediumgenomic DNA as a probe, dot blotting results showed that 56% clones are unique/low copy sequences, 44% are repetitive sequences in the library. Four Ag. intermedium clones were screened from the library by RFLP, and three clones(Mag065, Mag088, Mag139)belong to low/single sequences, one clone(Mag104)was repetitive sequence, and GISH results indicated that Mag104 was Ag.intermedium species-specific repetitive DNA sequence.

  1. DNA expressions - A formal notation for DNA

    NARCIS (Netherlands)

    Vliet, Rudy van

    2015-01-01

    We describe a formal notation for DNA molecules that may contain nicks and gaps. The resulting DNA expressions denote formal DNA molecules. Different DNA expressions may denote the same molecule. Such DNA expressions are called equivalent. We examine which DNA expressions are minimal, which

  2. DNA expressions - A formal notation for DNA

    NARCIS (Netherlands)

    Vliet, Rudy van

    2015-01-01

    We describe a formal notation for DNA molecules that may contain nicks and gaps. The resulting DNA expressions denote formal DNA molecules. Different DNA expressions may denote the same molecule. Such DNA expressions are called equivalent. We examine which DNA expressions are minimal, which

  3. SD-REE: A Cryptographic Method to Exclude Repetition from a Message

    CERN Document Server

    Dey, Somdip

    2012-01-01

    In this paper, the author presents a new cryptographic technique, SD-REE, to exclude the repetitive terms in a message, when it is to be encrypted, so that it becomes almost impossible for a person to retrieve or predict the original message from the encrypted message. In modern world, cryptography hackers try to break a code or cryptographic algorithm [1,2] or retrieve the key, used for encryption, by inserting repetitive bytes / characters in the message and encrypt the message or by analyzing repetitions in the encrypted message, to find out the encryption algorithm or retrieve the key used for the encryption. But in SD-REE method the repetitive bytes / characters are removed and there is no trace of any repetition in the message, which was encrypted.

  4. Feasibility of High-Repetition, Task-Specific Training for Individuals With Upper-Extremity Paresis

    Science.gov (United States)

    Waddell, Kimberly J.; Birkenmeier, Rebecca L.; Moore, Jennifer L.; Hornby, T. George

    2014-01-01

    OBJECTIVE. We investigated the feasibility of delivering an individualized, progressive, high-repetition upper-extremity (UE) task-specific training protocol for people with stroke in the inpatient rehabilitation setting. METHOD. Fifteen patients with UE paresis participated in this study. Task-specific UE training was scheduled for 60 min/day, 4 days/wk, during occupational therapy for the duration of a participant’s inpatient stay. During each session, participants were challenged to complete ≥300 repetitions of various tasks. RESULTS. Participants averaged 289 repetitions/session, spending 47 of 60 min in active training. Participants improved on impairment and activity level outcome measures. CONCLUSION. People with stroke in an inpatient setting can achieve hundreds of repetitions of task-specific training in 1-hr sessions. As expected, all participants improved on functional outcome measures. Future studies are needed to determine whether this high-repetition training program results in better outcomes than current UE interventions. PMID:25005508

  5. Serial rapists and their victims: reenactment and repetition.

    Science.gov (United States)

    Burgess, A W; Hazelwood, R R; Rokous, F E; Hartman, C R; Burgess, A G

    1988-01-01

    The major finding in this study of 41 serial rapists is the large numbers of reported and unreported victims. For over 1200 attempted and completed rapes, there were 200 convictions. The hidden rapes or earliest nonreported victims of these men as boys and adolescents were identified from their families, their neighborhood, and their schools. Examining the possible link between childhood sexual abuse and criminal behavior in this sample of 41 serial rapists, 56.1% were judged to have at least one forced or exploitive abuse experience in boyhood, as compared to a study of 2,972 college males reporting 7.3% experiencing boyhood sexual abuse. Looking within the abused samples, 56.1% of the rapists reported forced sex, compared to the college sample's 30.4%. Also, the rapist sample revealed higher rates of family member as abuser (48.4%), compared to 22.2% for the college sample. Retrospective reconstruction of the sexual activities and assertive behaviors of these men as boys reveals that 51% of the boys reenact the abuse as a preadolescent with their earliest victims being known to them (48% as neighborhood girls), family (25% as sisters), or girlfriend (25%). The onset of rape fantasies in midadolescence (mean age 16.9) crystalizes the earlier sexually initiated behaviors into juvenile behaviors of spying, fetish burglaries, molestations, and rapes. Repetition of these juvenile behaviors set their criminal patters on strangers--their next group of victims. To reduce victimization, serial rapists need to be identified early and stopped. This means acknowledging and reporting boy sexual abuse. This includes being sensitive to the reenactment behaviors noted in the initiated activities of abused children, which in turn need to be differentiated from peer play. Closer attention needs to be paid to families with incest behavior to insure that younger children are protected. Adolescents showing early repetitive juvenile delinquent behaviors must be assessed for physical

  6. DNA and RNA sensor

    Institute of Scientific and Technical Information of China (English)

    LIU; Tao; LIN; Lin; ZHAO; Hong; JIANG; Long

    2005-01-01

    This review summarizes recent advances in DNA sensor. Major areas of DNA sensor covered in this review include immobilization methods of DNA, general techniques of DNA detection and application of nanoparticles in DNA sensor.

  7. What Is Mitochondrial DNA?

    Science.gov (United States)

    ... DNA What is mitochondrial DNA? What is mitochondrial DNA? Although most DNA is packaged in chromosomes within ... proteins. For more information about mitochondria and mitochondrial DNA: Molecular Expressions, a web site from the Florida ...

  8. The HSP expression of passive repetitive plyometric trained skeletal muscle.

    Science.gov (United States)

    Hsu, Cheng-Chen; Hsu, Mei-Chich; Huang, Mao-Shung; Chen, Chuan-Show; Shiang, Tzyy-Yuang; Wang, Chiou-Huey; Chen, Tzuping; Su, Borcherng

    2005-01-01

    This study aims to understand the effect of ten-week passive repetitive plyometric (PRP) training on human skeletal muscle and the application of PRP training for performance. Vastus lateralis of nine candidates were aspirated before (pre) and after (post) PRP training. Histochemical approaches with regular hematoxylene-eosin (HE) and Mallory's phosphotungstic acid hematoxylin (PTAH) stains were used to demonstrate the changes of muscle fibers. Immunohistochemical studies with heat shock protein (anti-hsp72, Stressgen, Canada) were employed to display cellular activities. Each set of slides was quantitatively analyzed by using a modified morphometric method (Russ and Dehoff, 1999) on a Nikon ECLIPSE 80i microscope, equipped with an Evolution VF COOLED color video camera, and the Image-Pro Plus software (5.0 for Win; Media Cybernetics, USA). Finally, hsp72 mRNAs of both pre-PRP and post-PRP specimens were amplified through RT-PCR. Signal intensities were read by a densitometer and analyzed through the SPSS (11.0 for Win) statistically. Post-PRP muscle cells demonstrated hypertrophic change with increased cellular content and a narrowed inter-cellular space according to both HE and PTAH profiles. Post-PRP cellular hsp72 proteins were higher by up to five percent, as measured by a gray-scale reading. Further, after a training period of 10 weeks, hsp72 mRNA expression was several times higher.

  9. Developments of repetitive pneumatic pipe-gun pellet injector

    Energy Technology Data Exchange (ETDEWEB)

    Sudo, Shigeru [National Inst. for Fusion Science, Nagoya (Japan); Viniar, I.

    1997-05-01

    A pellet injector of repetitive pneumatic pipe-gun type has been designed for advanced plasma fueling applications. This new concept is estimated to be able to reduce the time for pellet formation by an in situ technique from 3 - 5 minutes to 2 - 10 seconds. The basic idea of the new approach to pellet formation is to supply a hydrogen isotope pellet through a copper porous unit into a pipe-gun-type barrel. Two modes are possible: (1) to push liquid hydrogen isotope through a porous unit and re-freezing inside of the barrel, (2) to push solid hydrogen isotope through a porous unit to the inside of the barrel. This principle provides a continuous injection of an unlimited amount of pellets. For demonstration of the proof-of-principle, several experiments have been carried out. Hydrogen pellets of 3 mm in diameter and 3 to 10 mm in length were accelerated to 1.2 km/s at a rate of 1 pellet per 10 - 34 s with a manually controlled injector operation. (author)

  10. Electromyographical Study on Muscle Fatigue in Repetitive Forearm Tasks

    Institute of Scientific and Technical Information of China (English)

    DAI Wentao; ZHAO Xiaorong; WANG Zhenglun; YANG Lei

    2007-01-01

    The purpose of this study was to examine whether repetitive muscle tasks in low weight load might influence the fatigue of forearm muscles, and to identify ergonomic risk factors of forearm muscle fatigue in these tasks. Sixteen healthy male volunteers performed eight wrist extensions in different frequency, weight and angle loads while being instructed to keep a dominant upper limb posture as constant as possible. Surface electromyograph (sEMG) was recorded from right extensors digitorium (ED), flexor carpi radialis (FCR), flexor carpi ulnaris (FCU) and extensor carpi ulnaris (ECU) during the task performance. Our results showed that mean power frequency (MPF) and median frequency (MF) values of ED, FCR and FCU were significantly lower (P<0.05) at high frequency load level than at low load level. However, MPF and MF values of ED were significantly lower (P<0.01) in higher load groups of frequency, angle and weight than in lower load groups. These results indicated that the fatigue of muscles varied in the same task, and the number-one risk factor of ECU, ED and FCR was angle load.

  11. The interaction between duration, velocity and repetitive auditory stimulation.

    Science.gov (United States)

    Makin, Alexis D J; Poliakoff, Ellen; Dillon, Joe; Perrin, Aimee; Mullet, Thomas; Jones, Luke A

    2012-03-01

    Repetitive auditory stimulation (with click trains) and visual velocity signals both have intriguing effects on the subjective passage of time. Previous studies have established that prior presentation of auditory clicks increases the subjective duration of subsequent sensory input, and that faster moving stimuli are also judged to have been presented for longer (the time dilation effect). However, the effect of clicks on velocity estimation is unknown, and the nature of the time dilation effect remains ambiguous. Here were present a series of five experiments to explore these phenomena in more detail. Participants viewed a rightward moving grating which traveled at velocities ranging from 5 to 15°/s and which lasted for durations of 500 to 1500 ms. Gratings were preceded by clicks, silence or white noise. It was found that both clicks and higher velocities increased subjective duration. It was also found that the time dilation effect was a constant proportion of stimulus duration. This implies that faster velocity increases the rate of the pacemaker component of the internal clock. Conversely, clicks increased subjective velocity, but the magnitude of this effect was not proportional to actual velocity. Through considerations of these results, we conclude that clicks independently affect velocity and duration representations.

  12. Improved discrimination of visual stimuli following repetitive transcranial magnetic stimulation.

    Directory of Open Access Journals (Sweden)

    Michael L Waterston

    Full Text Available BACKGROUND: Repetitive transcranial magnetic stimulation (rTMS at certain frequencies increases thresholds for motor-evoked potentials and phosphenes following stimulation of cortex. Consequently rTMS is often assumed to introduce a "virtual lesion" in stimulated brain regions, with correspondingly diminished behavioral performance. METHODOLOGY/PRINCIPAL FINDINGS: Here we investigated the effects of rTMS to visual cortex on subjects' ability to perform visual psychophysical tasks. Contrary to expectations of a visual deficit, we find that rTMS often improves the discrimination of visual features. For coarse orientation tasks, discrimination of a static stimulus improved consistently following theta-burst stimulation of the occipital lobe. Using a reaction-time task, we found that these improvements occurred throughout the visual field and lasted beyond one hour post-rTMS. Low-frequency (1 Hz stimulation yielded similar improvements. In contrast, we did not find consistent effects of rTMS on performance in a fine orientation discrimination task. CONCLUSIONS/SIGNIFICANCE: Overall our results suggest that rTMS generally improves or has no effect on visual acuity, with the nature of the effect depending on the type of stimulation and the task. We interpret our results in the context of an ideal-observer model of visual perception.

  13. Power neodymium-glass amplifier of a repetitively pulsed laser

    Energy Technology Data Exchange (ETDEWEB)

    Vinogradov, Aleksandr V; Gaganov, V E; Garanin, Sergey G; Zhidkov, N V; Krotov, V A; Martynenko, S P; Pozdnyakov, E V; Solomatin, I I [Russian Federal Nuclear Center ' All-Russian Research Institute of Experimental Physics' , Sarov, Nizhnii Novgorod region (Russian Federation)

    2011-11-30

    A neodymium-glass diode-pumped amplifier with a zigzag laser beam propagation through the active medium was elaborated; the amplifier is intended for operation in a repetitively pulsed laser. An amplifier unit with an aperture of 20 Multiplication-Sign 25 mm and a {approx}40-cm long active medium was put to a test. The energy of pump radiation amounts to 140 J at a wavelength of 806 nm for a pump duration of 550 {mu}s. The energy parameters of the amplifier were experimentally determined: the small-signal gain per pass {approx}3.2, the linear gain {approx}0.031 cm{sup -1} with a nonuniformity of its distribution over the aperture within 15%, the stored energy of 0.16 - 0.21 J cm{sup -3}. The wavefront distortions in the zigzag laser-beam propagation through the active element of the amplifier did not exceed 0.4{lambda} ({lambda} = 0.63 {mu}m is the probing radiation wavelength).

  14. Use of repetitive transcranial magnetic stimulation for treatment in psychiatry.

    Science.gov (United States)

    Aleman, André

    2013-08-01

    The potential of noninvasive neurostimulation by repetitive transcranial magnetic stimulation (rTMS) for improving psychiatric disorders has been studied increasingly over the past two decades. This is especially the case for major depression and for auditory-verbal hallucinations in schizophrenia. The present review briefly describes the background of this novel treatment modality and summarizes evidence from clinical trials into the efficacy of rTMS for depression and hallucinations. Evidence for efficacy in depression is stronger than for hallucinations, although a number of studies have reported clinically relevant improvements for hallucinations too. Different stimulation parameters (frequency, duration, location of stimulation) are discussed. There is a paucity of research into other psychiatric disorders, but initial evidence suggests that rTMS may also hold promise for the treatment of negative symptoms in schizophrenia, obsessive compulsive disorder and post-traumatic stress disorder. It can be concluded that rTMS induces alterations in neural networks relevant for psychiatric disorders and that more research is needed to elucidate efficacy and underlying mechanisms of action.

  15. Embryotoxicity following repetitive maternal exposure to scorpion venom

    Directory of Open Access Journals (Sweden)

    BN Hmed

    2012-01-01

    Full Text Available Although it is a frequent accident in a few countries, scorpion envenomation during pregnancy remains scarcely studied. In the present study, the effects of repetitive maternal exposure to Buthus occitanus tunetanus venom are investigated and its possible embryotoxic consequences on rats. Primigravid rats received a daily intraperitoneal dose of 1 mL/kg of saline solution or 300 µg/kg of crude scorpion venom, from the 7th to the 13th day of gestation. On the 21st day, the animals were deeply anesthetized using diethyl-ether. Then, blood was collected for chemical parameter analysis. Following euthanasia, morphometric measurements were carried out. The results showed a significant increase in maternal heart and lung absolute weights following venom treatment. However, the mean placental weight per rat was significantly diminished. Furthermore, blood urea concentration was higher in exposed rats (6.97 ± 0.62 mmol/L than in those receiving saline solution (4.94 ± 0.90 mmol/L. Many organs of venom-treated rat fetuses (brain, liver, kidney and spleen were smaller than those of controls. On the contrary, fetal lungs were significantly heavier in fetuses exposed to venom (3.2 ± 0.4 g than in the others (3.0 ± 0.2 g. Subcutaneous blood clots, microphthalmia and total body and tail shortening were also observed in venom-treated fetuses. It is concluded that scorpion envenomation during pregnancy potentially causes intrauterine fetal alterations and growth impairment.

  16. [Repetitive transcranial magnetic stimulation: A potential therapy for cognitive disorders?

    Science.gov (United States)

    Nouhaud, C; Sherrard, R M; Belmin, J

    2017-03-01

    Considering the limited effectiveness of drugs treatments in cognitive disorders, the emergence of noninvasive techniques to modify brain function is very interesting. Among these techniques, repetitive transcranial magnetic stimulation (rTMS) can modulate cortical excitability and have potential therapeutic effects on cognition and behaviour. These effects are due to physiological modifications in the stimulated cortical tissue and their associated circuits, which depend on the parameters of stimulation. The objective of this article is to specify current knowledge and efficacy of rTMS in cognitive disorders. Previous studies found very encouraging results with significant improvement of higher brain functions. Nevertheless, these few studies have limits: a few patients were enrolled, the lack of control of the mechanisms of action by brain imaging, insufficiently formalized technique and variability of cognitive tests. It is therefore necessary to perform more studies, which identify statistical significant improvement and to specify underlying mechanisms of action and the parameters of use of the rTMS to offer rTMS as a routine therapy for cognitive dysfunction.

  17. Repetitive transcranial magnetic stimulator with controllable pulse parameters

    Science.gov (United States)

    Peterchev, Angel V.; Murphy, David L.; Lisanby, Sarah H.

    2011-06-01

    The characteristics of transcranial magnetic stimulation (TMS) pulses influence the physiological effect of TMS. However, available TMS devices allow very limited adjustment of the pulse parameters. We describe a novel TMS device that uses a circuit topology incorporating two energy storage capacitors and two insulated-gate bipolar transistor (IGBT) modules to generate near-rectangular electric field pulses with adjustable number, polarity, duration, and amplitude of the pulse phases. This controllable pulse parameter TMS (cTMS) device can induce electric field pulses with phase widths of 10-310 µs and positive/negative phase amplitude ratio of 1-56. Compared to conventional monophasic and biphasic TMS, cTMS reduces energy dissipation up to 82% and 57% and decreases coil heating up to 33% and 41%, respectively. We demonstrate repetitive TMS trains of 3000 pulses at frequencies up to 50 Hz with electric field pulse amplitude and width variability less than the measurement resolution (1.7% and 1%, respectively). Offering flexible pulse parameter adjustment and reduced power consumption and coil heating, cTMS enhances existing TMS paradigms, enables novel research applications and could lead to clinical applications with potentially enhanced potency.

  18. Unraveling the cellular and molecular mechanisms of repetitive magnetic stimulation

    Directory of Open Access Journals (Sweden)

    Florian eMüller-Dahlhaus

    2013-12-01

    Full Text Available Despite numerous clinical studies, which have investigated the therapeutic potential of repetitive transcranial magnetic stimulation (rTMS in various brain diseases, our knowledge of the cellular and molecular mechanisms underlying rTMS-based therapies remains limited. Thus, a deeper understanding of rTMS-induced neural plasticity is required to optimize current treatment protocols. Studies in small animals or appropriate in vitro preparations (including models of brain diseases provide highly useful experimental approaches in this context. State-of-the-art electrophysiological and live-cell imaging techniques that are well established in basic neuroscience can help answering some of the major questions in the field, such as (i which neural structures are activated during TMS, (ii how does rTMS induce Hebbian plasticity, and (iii are other forms of plasticity (e.g., metaplasticity, structural plasticity induced by rTMS? We argue that data gained from these studies will support the development of more effective and specific applications of rTMS in clinical practice.

  19. Combinatorics on words Christoffel words and repetitions in words

    CERN Document Server

    Berstel, Jean; Reutenauer, Christophe; Saliola, Franco V

    2008-01-01

    The two parts of this text are based on two series of lectures delivered by Jean Berstel and Christophe Reutenauer in March 2007 at the Centre de Recherches Mathématiques, Montréal, Canada. Part I represents the first modern and comprehensive exposition of the theory of Christoffel words. Part II presents numerous combinatorial and algorithmic aspects of repetition-free words stemming from the work of Axel Thue-a pioneer in the theory of combinatorics on words. A beginner to the theory of combinatorics on words will be motivated by the numerous examples, and the large variety of exercises, which make the book unique at this level of exposition. The clean and streamlined exposition and the extensive bibliography will also be appreciated. After reading this book, beginners should be ready to read modern research papers in this rapidly growing field and contribute their own research to its development. Experienced readers will be interested in the finitary approach to Sturmian words that Christoffel words offe...

  20. Characterizing Aciniform Silk Repetitive Domain Backbone Dynamics and Hydrodynamic Modularity

    Directory of Open Access Journals (Sweden)

    Marie-Laurence Tremblay

    2016-08-01

    Full Text Available Spider aciniform (wrapping silk is a remarkable fibrillar biomaterial with outstanding mechanical properties. It is a modular protein consisting, in Argiope trifasciata, of a core repetitive domain of 200 amino acid units (W units. In solution, the W units comprise a globular folded core, with five α-helices, and disordered tails that are linked to form a ~63-residue intrinsically disordered linker in concatemers. Herein, we present nuclear magnetic resonance (NMR spectroscopy-based 15N spin relaxation analysis, allowing characterization of backbone dynamics as a function of residue on the ps–ns timescale in the context of the single W unit (W1 and the two unit concatemer (W2. Unambiguous mapping of backbone dynamics throughout W2 was made possible by segmental NMR active isotope-enrichment through split intein-mediated trans-splicing. Spectral density mapping for W1 and W2 reveals a striking disparity in dynamics between the folded core and the disordered linker and tail regions. These data are also consistent with rotational diffusion behaviour where each globular domain tumbles almost independently of its neighbour. At a localized level, helix 5 exhibits elevated high frequency dynamics relative to the proximal helix 4, supporting a model of fibrillogenesis where this helix unfolds as part of the transition to a mixed α-helix/β-sheet fibre.

  1. Designing a Repetitive Group Sampling Plan for Weibull Distributed Processes

    Directory of Open Access Journals (Sweden)

    Aijun Yan

    2016-01-01

    Full Text Available Acceptance sampling plans are useful tools to determine whether the submitted lots should be accepted or rejected. An efficient and economic sampling plan is very desirable for the high quality levels required by the production processes. The process capability index CL is an important quality parameter to measure the product quality. Utilizing the relationship between the CL index and the nonconforming rate, a repetitive group sampling (RGS plan based on CL index is developed in this paper when the quality characteristic follows the Weibull distribution. The optimal plan parameters of the proposed RGS plan are determined by satisfying the commonly used producer’s risk and consumer’s risk at the same time by minimizing the average sample number (ASN and then tabulated for different combinations of acceptance quality level (AQL and limiting quality level (LQL. The results show that the proposed plan has better performance than the single sampling plan in terms of ASN. Finally, the proposed RGS plan is illustrated with an industrial example.

  2. Variation and repetition in the spelling of young children.

    Science.gov (United States)

    Treiman, Rebecca; Decker, Kristina; Kessler, Brett; Pollo, Tatiana Cury

    2015-04-01

    A number of investigators have suggested that young children, even those who do not yet represent the phonological forms of words in their spellings, tend to use different strings of letters for different words. However, empirical evidence that children possess a concept of between-word variation has been weak. In a study by Pollo, Kessler, and Treiman (2009), in fact, prephonological spellers were more likely to write different words in the same way than would be expected on the basis of chance, not less likely. In the current study, preschool-age prephonological and phonological spellers showed a tendency to repeat spellings and parts of spellings that they had recently used. However, even prephonological spellers (mean age∼4 years 8 months) showed more repetition when spelling the same word twice in succession than when spelling different words. The results suggest that children who have not yet learned to use writing to represent the sounds of speech show some knowledge that writing represents words and, thus, should vary to show differences between them. The results further suggest that in spelling, as in other domains, children have a tendency to repeat recent behaviors. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Replication, checkpoint suppression and structure of centromeric DNA.

    Science.gov (United States)

    Romeo, Francesco; Falbo, Lucia; Costanzo, Vincenzo

    2016-11-01

    Human centromeres contain large amounts of repetitive DNA sequences known as α satellite DNA, which can be difficult to replicate and whose functional role is unclear. Recently, we have characterized protein composition, structural organization and checkpoint response to stalled replication forks of centromeric chromatin reconstituted in Xenopus laevis egg extract. We showed that centromeric DNA has high affinity for SMC2-4 subunits of condensins and for CENP-A, it is enriched for DNA repair factors and suppresses the ATR checkpoint to ensure its efficient replication. We also showed that centromeric chromatin forms condensins enriched and topologically constrained DNA loops, which likely contribute to the overall structure of the centromere. These findings have important implications on how chromosomes are organized and genome stability is maintained in mammalian cells.

  4. DNA vaccines

    Science.gov (United States)

    Gregersen, Jens-Peter

    2001-12-01

    Immunization by genes encoding immunogens, rather than with the immunogen itself, has opened up new possibilities for vaccine research and development and offers chances for new applications and indications for future vaccines. The underlying mechanisms of antigen processing, immune presentation and regulation of immune responses raise high expectations for new and more effective prophylactic or therapeutic vaccines, particularly for vaccines against chronic or persistent infectious diseases and tumors. Our current knowledge and experience of DNA vaccination is summarized and critically reviewed with particular attention to basic immunological mechanisms, the construction of plasmids, screening for protective immunogens to be encoded by these plasmids, modes of application, pharmacokinetics, safety and immunotoxicological aspects. DNA vaccines have the potential to accelerate the research phase of new vaccines and to improve the chances of success, since finding new immunogens with the desired properties is at least technically less demanding than for conventional vaccines. However, on the way to innovative vaccine products, several hurdles have to be overcome. The efficacy of DNA vaccines in humans appears to be much less than indicated by early studies in mice. Open questions remain concerning the persistence and distribution of inoculated plasmid DNA in vivo, its potential to express antigens inappropriately, or the potentially deleterious ability to insert genes into the host cell's genome. Furthermore, the possibility of inducing immunotolerance or autoimmune diseases also needs to be investigated more thoroughly, in order to arrive at a well-founded consensus, which justifies the widespread application of DNA vaccines in a healthy population.

  5. DNA nanotechnology

    Directory of Open Access Journals (Sweden)

    Nadrian C Seeman

    2003-01-01

    We are all aware that the DNA found in cells is a double helix consisting of two antiparallel strands held together by specific hydrogen-bonded base pairs; adenine (A always pairs with thymine (T, and guanine (G always pairs with cytosine (C. The specificity of this base pairing and the ability to ensure that it occurs in this fashion (and not some other1 is key to the use of DNA in materials applications. The double helical arrangement of the two molecules leads to a linear helix axis, linear not in the geometrical sense of being a straight line, but in the topological sense of being unbranched. Genetic engineers discovered in the 1970s how to splice together pieces of DNA to add new genes to DNA molecules2, and synthetic chemists worked out convenient syntheses for short pieces of DNA (up to ∼100–150 units in the 1980s3. Regardless of the impact of these technologies on biological systems, hooking together linear molecules leads only to longer linear molecules, with circles, knots, and catenanes perhaps resulting from time to time.

  6. Characterization and distribution of repetitive elements in association with genes in the human genome.

    Science.gov (United States)

    Liang, Kai-Chiang; Tseng, Joseph T; Tsai, Shaw-Jenq; Sun, H Sunny

    2015-08-01

    Repetitive elements constitute more than 50% of the human genome. Recent studies implied that the complexity of living organisms is not just a direct outcome of a number of coding sequences; the repetitive elements, which do not encode proteins, may also play a significant role. Though scattered studies showed that repetitive elements in the regulatory regions of a gene control gene expression, no systematic survey has been done to report the characterization and distribution of various types of these repetitive elements in the human genome. Sequences from 5' and 3' untranslated regions and upstream and downstream of a gene were downloaded from the Ensembl database. The repetitive elements in the neighboring of each gene were identified and classified using cross-matching implemented in the RepeatMasker. The annotation and distribution of distinct classes of repetitive elements associated with individual gene were collected to characterize genes in association with different types of repetitive elements using systems biology program. We identified a total of 1,068,400 repetitive elements which belong to 37-class families and 1235 subclasses that are associated with 33,761 genes and 57,365 transcripts. In addition, we found that the tandem repeats preferentially locate proximal to the transcription start site (TSS) of genes and the major function of these genes are involved in developmental processes. On the other hand, interspersed repetitive elements showed a tendency to be accumulated at distal region from the TSS and the function of interspersed repeat-containing genes took part in the catabolic/metabolic processes. Results from the distribution analysis were collected and used to construct a gene-based repetitive element database (GBRED; http://www.binfo.ncku.edu.tw/GBRED/index.html). A user-friendly web interface was designed to provide the information of repetitive elements associated with any particular gene(s). This is the first study focusing on the gene

  7. Loss of ATRX, associated with DNA methylation pattern of chromosome end, impacted biological behaviors of astrocytic tumors

    OpenAIRE

    CAI, JINQUAN; Chen, Jing; Zhang, Wei; Yang, Pei; Zhang, Chuanbao; Li, Mingyang; Yao, Kun; Wang, Hongjun; Li, Qingbin; Jiang, Chuanlu; Jiang., Tao

    2015-01-01

    Loss of ATRX leads to epigenetic alterations, including abnormal levels of DNA methylation at repetitive elements such as telomeres in murine cells. We conducted an extensive DNA methylation and mRNA expression profile study on a cohort of 82 patients with astrocytic tumors to study whether ATRX expression was associated with DNA methylation level in astrocytic tumors and in which cellular functions it participated. We observed that astrocytic tumors with lower ATRX expression harbored higher...

  8. Fuzzy Adaptive Repetitive Control for Periodic Disturbance with Its Application to High Performance Permanent Magnet Synchronous Motor Speed Servo Systems

    National Research Council Canada - National Science Library

    Junxiao Wang

    2016-01-01

    .... Then, the mathematical model of PMSM is given. Subsequently, a fuzzy adaptive repetitive controller based on repetitive control and fuzzy logic control is designed for the PMSM speed servo system...

  9. Safety and efficacy of low fluence, high repetition rate versus high fluence, low repetition rate 810-nm diode laser for axillary hair removal in Chinese women.

    Science.gov (United States)

    Li, Wenhai; Liu, Chengyi; Chen, Zhou; Cai, Lin; Zhou, Cheng; Xu, Qianxi; Li, Houmin; Zhang, Jianzhong

    2016-11-01

    High-fluence diode lasers with contact cooling have emerged as the gold standard to remove unwanted hair. Lowering the energy should result in less pain and could theoretically affect the efficacy of the therapy. To compare the safety and efficacy of a low fluence high repetition rate 810-nm diode laser to those of a high fluence, low repetition rate diode laser for permanent axillary hair removal in Chinese women. Ninety-two Chinese women received four axillae laser hair removal treatments at 4-week intervals using the low fluence, high repetition rate 810-nm diode laser in super hair removal (SHR) mode on one side and the high fluence, low repetition rate diode laser in hair removal (HR) mode on the other side. Hair counts were done at each follow-up visit and 6-month follow-up after the final laser treatment using a "Hi Quality Hair Analysis Program System"; the immediate pain score after each treatment session was recorded by a visual analog scale. The overall median reduction of hair was 90.2% with the 810-nm diode laser in SHR mode and 87% with the same laser in HR mode at 6-month follow-up. The median pain scores in SHR mode and in HR mode were 2.75 and 6.75, respectively. Low fluence, high repetition rate diode laser can efficiently remove unwanted hair but also significantly improve tolerability and reduce adverse events during the course of treatment.

  10. Sentence repetition is a measure of children's language skills rather than working memory limitations.

    Science.gov (United States)

    Klem, Marianne; Melby-Lervåg, Monica; Hagtvet, Bente; Lyster, Solveig-Alma Halaas; Gustafsson, Jan-Eric; Hulme, Charles

    2015-01-01

    Sentence repetition tasks are widely used in the diagnosis and assessment of children with language difficulties. This paper seeks to clarify the nature of sentence repetition tasks and their relationship to other language skills. We present the results from a 2-year longitudinal study of 216 children. Children were assessed on measures of sentence repetition, vocabulary knowledge and grammatical skills three times at approximately yearly intervals starting at age 4. Sentence repetition was not a unique longitudinal predictor of the growth of language skills. A unidimensional language latent factor (defined by sentence repetition, vocabulary knowledge and grammatical skills) provided an excellent fit to the data, and language abilities showed a high degree of longitudinal stability. Sentence repetition is best seen as a reflection of an underlying language ability factor rather than as a measure of a separate construct with a specific role in language processing. Sentence repetition appears to be a valuable tool for language assessment because it draws upon a wide range of language processing skills. © 2014 The Authors. Developmental Science Published by John Wiley & Sons Ltd.

  11. Environmental conditions associated with repetitive behavior in a group of African elephants.

    Science.gov (United States)

    Hasenjager, Matthew J; Bergl, Richard A

    2015-01-01

    Repetitive movement patterns are commonly observed in zoo elephants. The extent to which these behaviors constitute a welfare concern varies, as their expression ranges from stereotypies to potentially beneficial anticipatory behaviors. Nevertheless, their occurrence in zoo animals is often viewed negatively. To better identify conditions that prompt their performance, observations were conducted on six African elephants (Loxodonta africana) at the North Carolina Zoo. Individuals spent most of their time engaged in feeding, locomotion, resting, and repetitive behavior. Both generalized estimating equation and zero-inflated negative binomial models were used to identify factors associated with increased rates of repetitive behavior. Time of day in conjunction with location on- or off-exhibit best explained patterns of repetitive behavior. Repetitive behaviors occurred at a lower rate in the morning when on-exhibit, as compared to afternoons on-exhibit or at any time of day off-exhibit. Increased repetitive behavior rates observed on-exhibit in the afternoon prior to the evening transfer and feeding were possibly anticipatory responses towards those events. In contrast, consistently elevated frequencies of repetitive behavior off-exhibit at all times of day could be related to differences in exhibit complexity between off-exhibit and on-exhibit areas, as well as a lack of additional foraging opportunities. Our study contributes valuable information on captive elephant behavior and represents a good example of how behavioral research can be employed to improve management of zoo animals.

  12. A longitudinal investigation of perfectionism and repetitive negative thinking in perinatal depression.

    Science.gov (United States)

    Egan, Sarah J; Kane, Robert T; Winton, Karen; Eliot, Catherine; McEvoy, Peter M

    2017-10-01

    Repetitive negative thinking and perfectionism have both been proposed as processes that are related to depressive symptoms. The purpose of this study was to investigate concurrent and prospective relationships between antenatal and postnatal depression, perfectionism, and repetitive negative thinking. A longitudinal design was used and 71 women were followed from their third trimester of pregnancy to six weeks post birth. A structural equation model was tested with antenatal perfectionism predicting antenatal repetitive negative thinking, perfectionism predicting postnatal depression, and antenatal repetitive negative thinking predicting antenatal and postnatal depression. The final model provided an adequate fit to the data but the pathway from antenatal repetitive negative thinking to postnatal depression was not significant. The findings provide support for the role of perfectionism and repetitive negative thinking in the onset and maintenance of perinatal symptoms of depression. It is suggested that future research investigates the efficacy of targeting repetitive negative thinking and perfectionism in pregnancy to examine if this can reduce perinatal depression. Copyright © 2017. Published by Elsevier Ltd.

  13. Physiological responses to four hours of low-level repetitive work.

    Science.gov (United States)

    Garde, A Helene; Hansen, Ase M; Jensen, Bente R

    2003-12-01

    The study investigated physiological responses to 4 hours of standardized low-level repetitive work. It was hypothesized that accumulative effects not observed after 1 hour could be found after 4 hours of repetitive work. Ten healthy women performed intermittent (5 seconds + 5 seconds) handgrip contractions at 10% of the maximal voluntary contraction combined with mental demands for concentration and attention. Muscle activity in the working forearm muscles, cardiovascular responses, and concentrations of biomarkers in biological fluids were recorded along with exerted force, performance, and ratings of perceived physical exertion (RPE), and perceived mental exertion. The urinary epinephrine, norepinephrine, and cortisol concentrations were higher during the repetitive task than on a reference day, but only the norepinephrine concentrations increased progressively during the 4 hours. In accordance, the RPE recorded for the hand, forearm, and shoulder regions increased progressively. For the remaining physiological measures, no accumulative changes were found. Forearm muscle activity was higher during a mental reference task with lower exerted force than during the repetitive task. The variation in exerted force was higher during the repetitive task than during a force reference task without mental demands. The urinary biomarkers were increased during the repetitive task. However, only norepinephrine increased progressively during the 4 hours. Forearm muscle activity during a mental reference task with low exerted force indicated attention-related muscle activity. Finally, it was indicated that repetitive work including high demands for attention is performed at the expense of the precision of the exerted force.

  14. Stigmatization of repetitive hand use in newspaper reports of hand illness.

    Science.gov (United States)

    Anthony, Shawn; Lozano-Calderon, Santiago; Ring, David

    2008-03-01

    Failure to provide a balanced evidence-based consideration of the role of activity in illness can stigmatize individuals and their activities. We assessed the prevalence of language that stigmatized repetitive hand use and those that use their hand repetitively in newspaper coverage of common hand illnesses. The LexisNexis Academic database was used to search five major US newspapers for articles containing keywords about common hand illnesses during a 3-year period. Article language was assessed for stigmatization of activities involving repetitive hand use as well as for stigmatization of patients who use their hand repetitively. One hundred and twenty-four articles on hand illnesses were identified. Of these, 65.3% of articles stigmatized activities involving repetitive hand use, including 96.6% of articles discussing overuse injury of the hand, 90% of articles discussing tendonitis or tenosynovitis, and 51.8% of articles discussing carpal tunnel syndrome. Patient stigmatization was documented in 30.6% of the newspaper articles. Stigmatizing statements were most commonly made by journalists (94.8%), followed by patients (3.1%), and physicians (2.1%). Language that stigmatizes repetitive hand use and patients who use their hand repetitively is prevalent among US newspaper articles. Both health professionals and journalists reporting health-related news should be more sensitive to the use of stigmatizing language and provide a more balanced, measured, and evidenced-based account of hand illnesses.

  15. Analysis of T-DNA/Host-Plant DNA Junction Sequences in Single-Copy Transgenic Barley Lines

    Directory of Open Access Journals (Sweden)

    Joanne G. Bartlett

    2014-01-01

    Full Text Available Sequencing across the junction between an integrated transfer DNA (T-DNA and a host plant genome provides two important pieces of information. The junctions themselves provide information regarding the proportion of T-DNA which has integrated into the host plant genome, whilst the transgene flanking sequences can be used to study the local genetic environment of the integrated transgene. In addition, this information is important in the safety assessment of GM crops and essential for GM traceability. In this study, a detailed analysis was carried out on the right-border T-DNA junction sequences of single-copy independent transgenic barley lines. T-DNA truncations at the right-border were found to be relatively common and affected 33.3% of the lines. In addition, 14.3% of lines had rearranged construct sequence after the right border break-point. An in depth analysis of the host-plant flanking sequences revealed that a significant proportion of the T-DNAs integrated into or close to known repetitive elements. However, this integration into repetitive DNA did not have a negative effect on transgene expression.

  16. Chromosome mapping of repetitive sequences in four Serrasalmidae species (Characiformes

    Directory of Open Access Journals (Sweden)

    Leila Braga Ribeiro

    2014-01-01

    Full Text Available The Serrasalmidae family is composed of a number of commercially interesting species, mainly in the Amazon region where most of these fishes occur. In the present study, we investigated the genomic organization of the 18S and 5S rDNA and telomeric sequences in mitotic chromosomes of four species from the basal clade of the Serrasalmidae family: Colossoma macropomum, Mylossoma aureum, M. duriventre, and Piaractus mesopotamicus, in order to understand the chromosomal evolution in the family. All the species studied had diploid numbers 2n = 54 and exclusively biarmed chromosomes, but variations of the karyotypic formulas were observed. C-banding resulted in similar patterns among the analyzed species, with heterochromatic blocks mainly present in centromeric regions. The 18S rDNA mapping of C. macropomum and P. mesopotamicus revealed multiple sites of this gene; 5S rDNA sites were detected in two chromosome pairs in all species, although not all of them were homeologs. Hybridization with a telomeric probe revealed signals in the terminal portions of chromosomes in all the species and an interstitial signal was observed in one pair of C. macropomum.

  17. Design optimization methods for genomic DNA tiling arrays.

    Science.gov (United States)

    Bertone, Paul; Trifonov, Valery; Rozowsky, Joel S; Schubert, Falk; Emanuelsson, Olof; Karro, John; Kao, Ming-Yang; Snyder, Michael; Gerstein, Mark

    2006-02-01

    A recent development in microarray research entails the unbiased coverage, or tiling, of genomic DNA for the large-scale identification of transcribed sequences and regulatory elements. A central issue in designing tiling arrays is that of arriving at a single-copy tile path, as significant sequence cross-hybridization can result from the presence of non-unique probes on the array. Due to the fragmentation of genomic DNA caused by the widespread distribution of repetitive elements, the problem of obtaining adequate sequence coverage increases with the sizes of subsequence tiles that are to be included in the design. This becomes increasingly problematic when considering complex eukaryotic genomes that contain many thousands of interspersed repeats. The general problem of sequence tiling can be framed as finding an optimal partitioning of non-repetitive subsequences over a prescribed range of tile sizes, on a DNA sequence comprising repetitive and non-repetitive regions. Exact solutions to the tiling problem become computationally infeasible when applied to large genomes, but successive optimizations are developed that allow their practical implementation. These include an efficient method for determining the degree of similarity of many oligonucleotide sequences over large genomes, and two algorithms for finding an optimal tile path composed of longer sequence tiles. The first algorithm, a dynamic programming approach, finds an optimal tiling in linear time and space; the second applies a heuristic search to reduce the space complexity to a constant requirement. A Web resource has also been developed, accessible at http://tiling.gersteinlab.org, to generate optimal tile paths from user-provided DNA sequences.

  18. Repetitive behavior profile and supersensitivity to amphetamine in the C58/J mouse model of autism.

    Science.gov (United States)

    Moy, Sheryl S; Riddick, Natallia V; Nikolova, Viktoriya D; Teng, Brian L; Agster, Kara L; Nonneman, Randal J; Young, Nancy B; Baker, Lorinda K; Nadler, Jessica J; Bodfish, James W

    2014-02-01

    Restricted repetitive behaviors are core symptoms of autism spectrum disorders (ASDs). The range of symptoms encompassed by the repetitive behavior domain includes lower-order stereotypy and self-injury, and higher-order indices of circumscribed interests and cognitive rigidity. Heterogeneity in clinical ASD profiles suggests that specific manifestations of repetitive behavior reflect differential neuropathology. The present studies utilized a set of phenotyping tasks to determine a repetitive behavior profile for the C58/J mouse strain, a model of ASD core symptoms. In an observational screen, C58/J demonstrated overt motor stereotypy, but not over-grooming, a commonly-used measure for mouse repetitive behavior. Amphetamine did not exacerbate motor stereotypy, but had enhanced stimulant effects on locomotion and rearing in C58/J, compared to C57BL/6J. Both C58/J and Grin1 knockdown mice, another model of ASD-like behavior, had marked deficits in marble-burying. In a nose poke task for higher-order repetitive behavior, C58/J had reduced holeboard exploration and preference for non-social, versus social, olfactory stimuli, but did not demonstrate cognitive rigidity following familiarization to an appetitive stimulus. Analysis of available high-density genotype data indicated specific regions of divergence between C58/J and two highly-sociable strains with common genetic lineage. Strain genome comparisons identified autism candidate genes, including Cntnap2 and Slc6a4, located within regions divergent in C58/J. However, Grin1, Nlgn1, Sapap3, and Slitrk5, genes linked to repetitive over-grooming, were not in regions of divergence. These studies suggest that specific repetitive phenotypes can be used to distinguish ASD mouse models, with implications for divergent underlying mechanisms for different repetitive behavior profiles.

  19. "Oh no, not again": representability and a repetitive remark

    Directory of Open Access Journals (Sweden)

    Matt Tierney

    2010-06-01

    Full Text Available

    Abstract (E: In their most repetitive moments, literature and film can help us respond to common critical assumptions about the temporality of trauma. Rather than posit trauma's latency, anteriority, or unrepresentability, I raise questions about its obviousness, interchangeability, and cliché. Moving past trauma theory, and into general questions about repetition and representation, I therefore turn to a phrase that has often been repeated in texts across a range of forms and genres: "Oh no, not again!"

     

    Abstract (F: Lorsqu’ils se font intensément répétitifs, cinéma et littérature  peuvent nous aider à revoir certaines hypoth

  20. Brain signal complexity rises with repetition suppression in visual learning.

    Science.gov (United States)

    Lafontaine, Marc Philippe; Lacourse, Karine; Lina, Jean-Marc; McIntosh, Anthony R; Gosselin, Frédéric; Théoret, Hugo; Lippé, Sarah

    2016-06-21

    Neuronal activity associated with visual processing of an unfamiliar face gradually diminishes when it is viewed repeatedly. This process, known as repetition suppression (RS), is involved in the acquisition of familiarity. Current models suggest that RS results from interactions between visual information processing areas located in the occipito-temporal cortex and higher order areas, such as the dorsolateral prefrontal cortex (DLPFC). Brain signal complexity, which reflects information dynamics of cortical networks, has been shown to increase as unfamiliar faces become familiar. However, the complementarity of RS and increases in brain signal complexity have yet to be demonstrated within the same measurements. We hypothesized that RS and brain signal complexity increase occur simultaneously during learning of unfamiliar faces. Further, we expected alteration of DLPFC function by transcranial direct current stimulation (tDCS) to modulate RS and brain signal complexity over the occipito-temporal cortex. Participants underwent three tDCS conditions in random order: right anodal/left cathodal, right cathodal/left anodal and sham. Following tDCS, participants learned unfamiliar faces, while an electroencephalogram (EEG) was recorded. Results revealed RS over occipito-temporal electrode sites during learning, reflected by a decrease in signal energy, a measure of amplitude. Simultaneously, as signal energy decreased, brain signal complexity, as estimated with multiscale entropy (MSE), increased. In addition, prefrontal tDCS modulated brain signal complexity over the right occipito-temporal cortex during the first presentation of faces. These results suggest that although RS may reflect a brain mechanism essential to learning, complementary processes reflected by increases in brain signal complexity, may be instrumental in the acquisition of novel visual information. Such processes likely involve long-range coordinated activity between prefrontal and lower order visual

  1. Role of repetitive transcranial magnetic stimulation in stroke rehabilitation.

    Science.gov (United States)

    Pinter, Michaela M; Brainin, Michael

    2013-01-01

    In recent years, efforts have focused on investigating the neurophysiological changes that occur in the brain after stroke, and on developing novel strategies such as additional brain stimulation to enhance sensorimotor and cognitive recovery. In the 1990s, repetitive transcranial magnetic stimulation (rTMS) was introduced as a therapeutic tool for improving the efficacy of rehabilitation for recovery after stroke. It is evident that disturbances of interhemispheric processes after stroke result in a pathological hyperactivity of the intact hemisphere. The rationale of using rTMS as a complementary therapy is mainly to decrease the cortical excitability in regions that are presumed to hinder optimal recovery by low-frequency rTMS delivered to the unaffected hemisphere, while high-frequency rTMS delivered to the affected hemisphere facilitates cortical excitability. However, the exact mechanisms of how rTMS works are still under investigation. There is a growing body of research in stroke patients investigating the effect of rTMS on facilitating recovery by modifying cortical and subcortical networks. Clinical trials applying rTMS already yielded promising results in improving recovery of sensorimotor and cognitive functions. Altogether, in combination with conventional therapeutic approaches, rTMS has a potential to become a complementary strategy to enhance stroke recovery by modulating the excitability of targeted brain areas. In future studies, emphasis should be placed on selecting patient populations to determine whether treatment response depends on age, lesion acuteness, or stroke severity. Furthermore, it is important to identify parameters optimizing the beneficial effects of rTMS on stroke recovery, and to monitor their long-term effects.

  2. Knowledge of Repetitions Range Affects Force Production in Trained Females

    Directory of Open Access Journals (Sweden)

    Israel Halperin, Saied J. Aboodarda, Fabien A. Basset, David G. Behm

    2014-12-01

    Full Text Available Most studies have examined pacing strategies with cyclical activities (running and cycling. It has been demonstrated that males employ different pacing strategies during repeated maximal voluntary contractions (MVCs dependent upon a known endpoint. Since different fatiguing mechanisms have been identified between the genders, it is not known if females use comparable pacing strategies. The purpose of this study was to examine if informing female subjects regarding the number of MVCs to perform would affect force and electromyography (EMG. Twenty well-trained females completed 3 fatiguing protocols in a randomized order. In the control condition participants were informed they would perform twelve MVCs and then actually completed twelve. In the unknown condition they were not told how many MVCs to perform but were stopped after twelve. In the deception condition they were initially informed to perform 6 MVCs, but after the 6th MVC they were asked to perform a few more MVCs and were stopped after twelve. During the first 6 MVCs, forces in the deception condition were greater compared to the unknown (p = 0.021, ES = 0.65, 5% and control (p = 0.022, ES = 0.42, 3% conditions. No differences were found between conditions in the last 6 MVCs. A main effect for repetitions showed force deficits during the first 6 MVCs (p = 0.000, ES = 1.81, 13% and last 6 MVCs (p = 0.05, ES = 0.34, 3%. No differences were found between conditions in biceps and triceps EMG. However, EMG decreased during the first 6 MVCs for biceps (p = 0.001, ES = 1.0, 14% and triceps (p = 0.001, ES = 0.76, 14% across conditions. No differences were found in the last 6 MVCs. The anticipation of performing fewer MVCs led to increased force, whereas no endpoint led to decreased force production.

  3. Molecular typing among beef isolates of Escherichia coli using consensus repetitive intergenic enterobacteria-polymerase chain reaction (ERIC-PCR)

    Science.gov (United States)

    Zoolkifli, Nurliyana Wan; Mutalib, Sahilah Abd

    2013-11-01

    Genomic DNA of Escherichia coli were characterized by enterobacterial repetitive intergenic consensus-Polymerase chain reaction (ERIC-PCR) and the presence of Shiga toxin gene-I (Stx1) and Shiga toxin gene-2 (Stx2). These isolates were originated from imported raw beef which are come from two countries namely Australia and India. The isolation of E. coli was conducted by using Eosin Methylene Blue Agar (EMBA). A total of 94 strains had been isolated from 30 samples of imported raw beefand 42 strains had been detected positively E. coli by doing biochemical tests. All strains had been tested and the results of biochemical tests showed that 3 strains were from Australia samples while the other 39 strains were from India samples. The biochemical tests used are Indole test, Methyl Red test, Voges-Proskauer test and Citrate test. All the 42 strains were examined for Shiga toxin (stx1 and stx2) gene detection by two pair primers which are stx2F (5'-TTCTTCGGTATCCTATTCCC-3'), stx2R (5'-ATGCATCTCTGGTCATTGTA-3'), stx1F (5'-CAGTTAATGTGGTGGCGAAG-3'), and stx1R (5'-CTGTCACAGTAACAACCGT-3'). The results showed that none of the strains are positive for Shiga toxin gene. Application of ERIC-PCR method towards E. coli had successfully shown the high diversity polymorphism in 21 different genome types of DNA with primers ERIC1R (5'- CACTTAGGGGTCCTCGAATGTA- 3') and ERIC2R (5'- AAGTAAGTGACTGGGGTGACGC- 3').

  4. DNA origami nanopores for controlling DNA translocation.

    Science.gov (United States)

    Hernández-Ainsa, Silvia; Bell, Nicholas A W; Thacker, Vivek V; Göpfrich, Kerstin; Misiunas, Karolis; Fuentes-Perez, Maria Eugenia; Moreno-Herrero, Fernando; Keyser, Ulrich F

    2013-07-23

    We combine DNA origami structures with glass nanocapillaries to reversibly form hybrid DNA origami nanopores. Trapping of the DNA origami onto the nanocapillary is proven by imaging fluorescently labeled DNA origami structures and simultaneous ionic current measurements of the trapping events. We then show two applications highlighting the versatility of these DNA origami nanopores. First, by tuning the pore size we can control the folding of dsDNA molecules ("physical control"). Second, we show that the specific introduction of binding sites in the DNA origami nanopore allows selective detection of ssDNA as a function of the DNA sequence ("chemical control").

  5. Unconscious Cognition Isn't that Smart: Modulation of Masked Repetition Priming Effect in the Word Naming Task

    Science.gov (United States)

    Kinoshita, Sachiko; Forster, Kenneth I.; Mozer, Michael C.

    2008-01-01

    Masked repetition primes produce greater facilitation in naming in a block containing a high, rather than low proportion of repetition trials. [Bodner, G. E., & Masson, M. E. J. (2004). "Beyond binary judgments: Prime-validity modulates masked repetition priming in the naming task". "Memory & Cognition", 32, 1-11] suggested this phenomenon…

  6. Femtosecond and picosecond laser drilling of metals at high repetition rates and average powers.

    Science.gov (United States)

    Ancona, A; Döring, S; Jauregui, C; Röser, F; Limpert, J; Nolte, S; Tünnermann, A

    2009-11-01

    The influence of pulse duration on the laser drilling of metals at repetition rates of up to 1 MHz and average powers of up to 70 W has been experimentally investigated using an ytterbium-doped-fiber chirped-pulse amplification system with pulses from 800 fs to 19 ps. At a few hundred kilohertz particle shielding causes an increase in the number of pulses for breakthrough, depending on the pulse energy and duration. At higher repetition rates, the heat accumulation effect overbalances particle shielding, but significant melt ejection affects the hole quality. Using femtosecond pulses, heat accumulation starts at higher repetition rates, and the ablation efficiency is higher compared with picosecond pulses.

  7. REPETITIVE MANUAL OPERATIONS IN THE DAIRY SECTOR: ANALYSES AND CRITERIA FOR INTERVENTION

    Directory of Open Access Journals (Sweden)

    Pier Riccardo Porceddu

    2008-03-01

    Full Text Available For the health of workers it is necessary to consider, together with traditional risks (noise, vibrations, microclimate etc., risks deriving from repetitive movements, which can generate muscolo-skeletal disorders. These risks can be found in artisan dairies, where the limited use of machinery and the rapid successive passages for processing the milk require high-frequency repetitive manual movements. The study analysed the risks of repetitive movements for workers in a dairy, using the OCRA method. Various risk-involving operations emerged, which require the re-planning of the workplace. The proposed interventions have not involved high costs for the dairy, or a loss of productivity.

  8. Pulsed pumped Yb-doped fiber amplifier at low repetition rate

    Institute of Scientific and Technical Information of China (English)

    Changgeng Ye; Ping Yan; Mali Gong; Ming Lei

    2005-01-01

    A pulsed pumped Yb-doped double-clad fiber (DCF) master-oscillator power amplifier (MOPA) at low repetition rate is reported. Seeded by a passive Q-switched Nd:YAG microchip laser, the fiber amplifier can generate 167-kW peak-power and 0.83-ns duration pulses at 200-Hz repetition rate. Because of the pulsed pump approach, the amplified spontaneous emission (ASE) and the spurious lasing between pulses are well avoided, and the repetition rate can be set freely from single-shot to 1 kHz. Peak power scaling limitations that arise from the fiber facet damage are discussed.

  9. Repetitive training for ameliorating upper limbs spasm of hemiplegic patients

    Institute of Scientific and Technical Information of China (English)

    Lin Zhu; Lin Liu; Weiqun Song

    2006-01-01

    BACKGROUND:The main aim of rehabilitation is to ameliorate motor function and use the damaged limbs in the activities of daily living.Several factors are needed in the self-recovery of the patients,and the most important one is to reduce spasm.Some mechanical repetitive movements can affect and change the excitability of motor neurons.OBJECTIVE:To observe the effect of repetitive training on ameliorating spasm of upper limbs of hemiplegic patients.DESIGN:A self-controlled observation before and after training.SETTING:Department of Rehabilitation,Xuanwu Hospital of Capital Medical University.PARTICI PANTS: Seven hemiplegic patients induced by brain injury were selected from the Department of Rehabilitation,Xuanwu Hospital,Capital Medical University from March to June in 2005.Inclusive criteria:①Agreed and able to participate in the 30-minute training of hand function; ②Without disturbance of understanding.The patients with aphasia or apraxia,manifestation of shoulder pain,and severe neurological or mental defects.For the 7 patients,the Rivermead motor assessment(RMA)scores ranged 0-10 points,the Rivermead mobility index(RMI)ranged 1-3,and modified Ashworth scale(MAS)was grade 2-4.Their horizontal extension of shoulder joint was 0°-30°,anteflextion was 0°-50°,internal rotation was 50°-90°,external rotation was 0°-10°:and the elbow joint could extend for 15°-135°.METHODS:The viva 2 serial MOTOmed exerciser(Reck Company,Germany)was used.There were three phases of A-B-A.①The phase A lasted for 1 week.The patient sat on a chair facting to the MOTOmed screen.and did the circumduction of upper limbs forwardly,30 minutes a day and 5 days a week.②The phase B lasted for 3 weeks.The training consisted of forward circumduction of upper limbs for 15 minutes.followed by backward ones for 15 minutes and 5-minute rest.③The training in the phase A was performed again for 2 weeks.The extensions of upper limbs were recorded at phase A,the extension and flexion of

  10. Chicken spermatogenesis is accompanied by a genomic-wide loss of DNA methylation.

    Science.gov (United States)

    Rocamora, N; Mezquita, C

    1989-04-24

    Renaturation kinetics of DNA obtained from chicken testis cell nuclei separated by sedimentation at unit gravity showed that the undermethylation, previously observed in meiotic and postmeiotic cells, is not a peculiarity of repetitive sequences, but is also a feature of unique sequences. The large proportion of slowly renaturing, intermediately renaturing and rapidly renaturing DNAs contain 27, 32 and 31% less methylcytosines in meiotic and postmeiotic cells than the corresponding fractions of premeiotic cells. DNA methyltransferase activity is lower in meiotic cells containing undermethylated DNA than in immature testis, enriched in spermatogonia, with higher levels of DNA methylation.

  11. Atypical epigenetic mark in an atypical location: cytosine methylation at asymmetric (CNN sites within the body of a non-repetitive tomato gene

    Directory of Open Access Journals (Sweden)

    Iusem Norberto D

    2011-05-01

    Full Text Available Abstract Background Eukaryotic DNA methylation is one of the most studied epigenetic processes, as it results in a direct and heritable covalent modification triggered by external stimuli. In contrast to mammals, plant DNA methylation, which is stimulated by external cues exemplified by various abiotic types of stress, is often found not only at CG sites but also at CNG (N denoting A, C or T and CNN (asymmetric sites. A genome-wide analysis of DNA methylation in Arabidopsis has shown that CNN methylation is preferentially concentrated in transposon genes and non-coding repetitive elements. We are particularly interested in investigating the epigenetics of plant species with larger and more complex genomes than Arabidopsis, particularly with regards to the associated alterations elicited by abiotic stress. Results We describe the existence of CNN-methylated epialleles that span Asr1, a non-transposon, protein-coding gene from tomato plants that lacks an orthologous counterpart in Arabidopsis. In addition, to test the hypothesis of a link between epigenetics modifications and the adaptation of crop plants to abiotic stress, we exhaustively explored the cytosine methylation status in leaf Asr1 DNA, a model gene in our system, resulting from water-deficit stress conditions imposed on tomato plants. We found that drought conditions brought about removal of methyl marks at approximately 75 of the 110 asymmetric (CNN sites analysed, concomitantly with a decrease of the repressive H3K27me3 epigenetic mark and a large induction of expression at the RNA level. When pinpointing those sites, we observed that demethylation occurred mostly in the intronic region. Conclusions These results demonstrate a novel genomic distribution of CNN methylation, namely in the transcribed region of a protein-coding, non-repetitive gene, and the changes in those epigenetic marks that are caused by water stress. These findings may represent a general mechanism for the

  12. Integrated view of genome structure and sequence of a single DNA molecule in a nanofluidic device

    DEFF Research Database (Denmark)

    Marie, Rodolphe; Pedersen, Jonas Nyvold; L. V. Bauer, David

    2013-01-01

    We show how a bird’s-eye view of genomic structure can be obtained at ∼1-kb resolution from long (∼2 Mb) DNA molecules extracted from whole chromosomes in a nanofluidic laboratoryon-a-chip. We use an improved single-molecule denaturation mapping approach to detect repetitive elements and known...

  13. DNA mismatch repair deficiency in sporadic colorectal cancer and Lynch Syndrome

    OpenAIRE

    Poulogiannis, George; Frayling, Ian; Arends, Mark

    2009-01-01

    Abstract DNA mismatch repair (MMR) deficiency is one of the best understood forms of genetic instability in colorectal cancer (CRC), and is characterised by the loss of function of the MMR pathway. Failure to repair replication-associated errors due to a defective MMR system allows persistence of mismatch mutations all over the genome, but especially in regions of repetitive DNA known as microsatellites, giving rise to the phenomenon of microsatellite instability (MSI). A high freq...

  14. Organization and evolution of Gorilla centromeric DNA from old strategies to new approaches

    OpenAIRE

    Catacchio, C. R.; Ragone, R.; Chiatante, G.; M. Ventura

    2015-01-01

    The centromere/kinetochore interaction is responsible for the pairing and segregation of replicated chromosomes in eukaryotes. Centromere DNA is portrayed as scarcely conserved, repetitive in nature, quickly evolving and protein-binding competent. Among primates, the major class of centromeric DNA is the pancentromeric α-satellite, made of arrays of 171 bp monomers, repeated in a head-to-tail pattern. α-satellite sequences can either form tandem heterogeneous monomeric arrays or assemble in h...

  15. Repetitive transcranial magnetic stimulation in cervical dystonia: effect of site and repetition in a randomized pilot trial.

    Directory of Open Access Journals (Sweden)

    Sarah Pirio Richardson

    Full Text Available Dystonia is characterized by abnormal posturing due to sustained muscle contraction, which leads to pain and significant disability. New therapeutic targets are needed in this disorder. The objective of this randomized, sham-controlled, blinded exploratory study is to identify a specific motor system target for non-invasive neuromodulation and to evaluate this target in terms of safety and tolerability in the cervical dystonia (CD population. Eight CD subjects were given 15-minute sessions of low-frequency (0.2 Hz repetitive transcranial magnetic stimulation (rTMS over the primary motor cortex (MC, dorsal premotor cortex (dPM, supplementary motor area (SMA, anterior cingulate cortex (ACC and a sham condition with each session separated by at least two days. The Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS score was rated in a blinded fashion immediately pre- and post-intervention. Secondary outcomes included physiology and tolerability ratings. The mean change in TWSTRS severity score by site was 0.25 ± 1.7 (ACC, -2.9 ± 3.4 (dPM, -3.0 ± 4.8 (MC, -0.5 ± 1.1 (SHAM, and -1.5 ± 3.2 (SMA with negative numbers indicating improvement in symptom control. TWSTRS scores decreased from Session 1 (15.1 ± 5.1 to Session 5 (11.0 ± 7.6. The treatment was tolerable and safe. Physiology data were acquired on 6 of 8 subjects and showed no change over time. These results suggest rTMS can modulate CD symptoms. Both dPM and MC are areas to be targeted in further rTMS studies. The improvement in TWSTRS scores over time with multiple rTMS sessions deserves further evaluation.

  16. Association between telomere length and CYP19 TTTA repetition polymorphism in healthy and breast cancer-diagnosed women

    Science.gov (United States)

    Murillo-Ortiz, Blanca; Martínez-Garza, Sandra; Suárez García, David; Castillo Valenzuela, Rosa del Carmen; García Regalado, Juan Francisco; Cano Velázquez, Gerardo

    2017-01-01

    Introduction Several studies have reported an increase in breast cancer (BC) risk when patients are carriers of the CYP19 TTA polymorphism with ≥10 repeats; moreover, it has been reported that telomere length is associated with a higher susceptibility of developing cancer. Objective The objective of this study was to understand the relationship between CYP19 TTTA repetition polymorphism and telomere length and its effects on serum estradiol, estrone and follicle-stimulating hormone (FSH). Materials and methods A total of 180 postmenopausal healthy and 70 BC-diagnosed women were included. Telomere length was determined through real-time quantitative polymerase chain reaction, and aromatase polymorphism was analyzed through DNA; both samples were obtained from circulating leukocytes. Serum estrone, estradiol and FSH were determined by enzyme-linked immunosorbent assay. Results Patients with a BC diagnosis showed >10 repetitions more frequently, compared with that of healthy women (50% vs 23%, χ2 = 11.44, p = 0.0007). A significant difference in telomere length between healthy and BC women was observed (5,042.7 vs 2,256.7 pb, Z = 4.88, p 10 repeats. Moreover, telomere length showed an inverse relationship with the number of repeats of the aromatase polymorphism in healthy women (R2 = 0.04, r = −0.24); in contrast, BC patients did not display this relationship. In addition, telomere length presented an inverse relationship with serum levels of estradiol and estrone in BC patients (p = 0.02). Conclusion Telomere length is shorter in BC patients than in healthy patients. The CYP19 TTTA repeat polymorphism is associated with serum levels of estradiol and estrone in both healthy women and BC patients, being higher in those with polymorphism carriers >10 repeats. Telomere length has an inverse correlation with the number of repeats of the aromatase polymorphism in healthy women but not in BC women. Estradiol and estrone levels in BC women have an inverse relationship

  17. Strand Breaks in DNA Samples Induced with LASERIX

    Science.gov (United States)

    Zielbauer, B.; Habib, J.; Kazamias, S.; Guilbaud, O.; Pittman, M.; Ros, D.; Hervé du Penhoat, M.-A.; Touati, A.; Sech, C. Le; Porcel, E.; Lacombe, S.

    Samples of plasmid DNA were irradiated with pulsed 18.9 nm radiation originating from a Mo X-ray laser pumped in GRIP configuration at the LASERIX facility [1]. Surface doses of up to 500 kGray were delivered with a repetition rate of 10 Hz and average pulse energy of 200 nJ. The occurrence of single and double strand breaks not present in controls having undergone the same treatment except for the XRL irradiation can be seen as a clear effect of the XRL irradiation. This confirms the role of direct effects in DNA damages as previously seen with low energy ions [2, 3] and electrons.

  18. Combinatorial codon scrambling enables scalable gene synthesis and amplification of repetitive proteins

    Science.gov (United States)

    Tang, Nicholas C.; Chilkoti, Ashutosh

    2016-04-01

    Most genes are synthesized using seamless assembly methods that rely on the polymerase chain reaction (PCR). However, PCR of genes encoding repetitive proteins either fails or generates nonspecific products. Motivated by the need to efficiently generate new protein polymers through high-throughput gene synthesis, here we report a codon-scrambling algorithm that enables the PCR-based gene synthesis of repetitive proteins by exploiting the codon redundancy of amino acids and finding the least-repetitive synonymous gene sequence. We also show that the codon-scrambling problem is analogous to the well-known travelling salesman problem, and obtain an exact solution to it by using De Bruijn graphs and a modern mixed integer linear programme solver. As experimental proof of the utility of this approach, we use it to optimize the synthetic genes for 19 repetitive proteins, and show that the gene fragments are amenable to PCR-based gene assembly and recombinant expression.

  19. Combinatorial codon scrambling enables scalable gene synthesis and amplification of repetitive proteins.

    Science.gov (United States)

    Tang, Nicholas C; Chilkoti, Ashutosh

    2016-04-01

    Most genes are synthesized using seamless assembly methods that rely on the polymerase chain reaction (PCR). However, PCR of genes encoding repetitive proteins either fails or generates nonspecific products. Motivated by the need to efficiently generate new protein polymers through high-throughput gene synthesis, here we report a codon-scrambling algorithm that enables the PCR-based gene synthesis of repetitive proteins by exploiting the codon redundancy of amino acids and finding the least-repetitive synonymous gene sequence. We also show that the codon-scrambling problem is analogous to the well-known travelling salesman problem, and obtain an exact solution to it by using De Bruijn graphs and a modern mixed integer linear programme solver. As experimental proof of the utility of this approach, we use it to optimize the synthetic genes for 19 repetitive proteins, and show that the gene fragments are amenable to PCR-based gene assembly and recombinant expression.

  20. Semantic Integration: Effects of Imagery, Enaction, and Sentence Repetition Training on Prereaders' Recall for Pictograph Sentences.

    Science.gov (United States)

    Ledger, George W.; Ryan, Ellen Bouchard

    1985-01-01

    Over a two-week period, examined the effectiveness of integrative imagery strategy over concrete enaction and repetition strategies for improving kindergartners' recall of pictograph sentences. (Author/BE)

  1. Concept mediation in trilingual translation: evidence from response time and repetition priming patterns.

    Science.gov (United States)

    Francis, Wendy S; Gallard, Sabrina L K

    2005-12-01

    Translation responses to individual words were elicited from 48 English-Spanish-French trilinguals, who translated in six directions at study and two directions at test. Patterns of translation response times and error rates at study reflected the relative proficiency of the trilinguals in comprehension and production of their three languages. At test, repeated items were translated more quickly than new items, with the strongest priming effects occurring for identical repetitions. Repetition priming was also substantial when only the stimulus language or only the response language matched from study to test, implying that repeated comprehension and production processes contribute to priming in translation. Patterns of response times and repetition priming indicate that translation in all directions involved conceptual access. Additive patterns in response time asymmetries and repetition priming were consistent with the treatment of word comprehension and production processes of translation as independent.

  2. Hydrodynamic size distribution of gold nanoparticles controlled by repetition rate during pulsed laser ablation in water

    Science.gov (United States)

    Menéndez-Manjón, Ana; Barcikowski, Stephan

    2011-02-01

    Most investigations on the laser generation and fragmentation of nanoparticles focus on Feret particle size, although the hydrodynamic size of nanoparticles is of great importance, for example in biotechnology for diffusion in living cells, or in engineering, for a tuned rheology of suspensions. In this sense, the formation and fragmentation of gold colloidal nanoparticles using femtosecond laser ablation at variable pulse repetition rates (100-5000 Hz) in deionized water were investigated through their plasmon resonance and hydrodynamic diameter, measured by Dynamic Light Scattering. The increment of the repetition rate does not influence the ablation efficiency, but produces a decrease of the hydrodynamic diameter and blue-shift of the plasmon resonance of the generated gold nanoparticles. Fragmentation, induced by inter-pulse irradiation of the colloids was measured online, showing to be more effective low repetition rates. The pulse repetition rate is shown to be an appropriate laser parameter for hydrodynamic size control of nanoparticles without further influence on the production efficiency.

  3. High Energy Single Frequency Fiber Laser at Low Repetition Rate Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR phase II project proposes a single frequency high energy fiber laser system operating at low repetition rate of 10 Hz to 1 kHz for coherent Lidar systems...

  4. Multiple Description Spherical Quantization of Sinusoidal Parameters with Repetition Coding of the Amplitudes

    DEFF Research Database (Denmark)

    Jensen, Jesper Rindom; Christensen, Mads Græsbøll; Larsen, Morten Holm

    2009-01-01

    Recently, multiple description spherical trellis-coded quantization (MDSTCQ) for quantization of sinusoidal parameters was proposed, which suffered from a suboptimal implementation. Therefore, we propose the multiple description spherical quantization with repetition coding of the amplitudes (MDS...

  5. Evaluation of Na+/K+ pump function following repetitive activity in mouse peripheral nerve

    DEFF Research Database (Denmark)

    Moldovan, Mihai; Krarup, Christian

    2006-01-01

    excitability measures simultaneously from the evoked plantar compound muscle action potential (CMAP) and sciatic compound nerve action potential (CNAP). Three minutes after repetitive supramaximal stimulation maximal CMAP and CNAP amplitudes recovered but the threshold was increased approximately 40% for motor...

  6. Stability of Closed Loop Controlled Repetitive Periodic System applied to control of CD-Player

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob; Andersen, Palle

    2005-01-01

    In this paper a criterion for stability of specific control scheme for handling linear dynamic control systems with repetitive periodic sensor faults is derived. The given system and control scheme are described and defined. By combining these with the lifting technique a necessary and sufficient...... the repetitive sensor faults (surface faults). The fault approximations are subsequently subtracted from the measurements, and the influence from these repetitive sensor faults are thereby removed from the computed control signals....... stability criterion is derived. This criterion is following applied to an example on a feature based control scheme for handling CD-players playing CDs with surface faults. This feature based control scheme is handling repetitive periodic sensor faults. The feature based control scheme approximates...

  7. Repetitive control mechanism of disturbance cancellation using a hybrid regression and genetic algorithm

    Science.gov (United States)

    Lin, Jeng-Wen; Shen, Pu Fun; Wen, Hao-Ping

    2015-10-01

    The application of a repetitive control mechanism for use in a mechanical control system has been a topic of investigation. The fundamental purpose of repetitive control is to eliminate disturbances in a mechanical control system. This paper presents two different repetitive control laws using individual types of basis function feedback and their combinations. These laws adjust the command given to a feedback control system to eliminate tracking errors, generally resulting from periodic disturbance. Periodic errors can be reduced through linear basis functions using regression and a genetic algorithm. The results illustrate that repetitive control is most effective method for eliminating disturbances. When the data are stabilized, the tracking error of the obtained convergence value, 10-14, is the optimal solution, verifying that the proposed regression and genetic algorithm can satisfactorily reduce periodic errors.

  8. Repetitive negative thinking and suicide: a burgeoning literature with need for further exploration.

    Science.gov (United States)

    Law, Keyne C; Tucker, Raymond P

    2017-08-24

    Extant research has found a significant overlap between various repetitive negative thinking (RNT) patterns, such as rumination and worry, across different affective disorders implicating that the process of repetitive negative thinking is likely trans-diagnostic. Furthermore, RNT patterns at the core of psychiatric disorders associated with suicide (e.g., rumination and worry) have been found to be associated with suicide even after accounting for the disorder. A synthesis of existing literature on repetitive negative thoughts suggest that following negative emotional experiences, RNTs may lead to a sense of entrapment and hopelessness that may contribute to the onset of suicidal ideation and then facilitate the transition from thinking about suicide to making a suicide attempt by increasing an individual's capability for suicide through repetitive exposure to violent thoughts and imagery associated with suicide. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. An evaluation of factors affecting duration of treatment with repetitive transcranial magnetic stimulation for depression

    Directory of Open Access Journals (Sweden)

    Roni Broder Cohen

    2007-12-01

    Full Text Available Objective: To investigate the effects of repetitive transcranialmagnetic stimulation in patients with major depression who weresubmitted to this treatment during the period from 2000 to 2006.Methods: A retrospective study with 204 patients who underwenttreatment with repetitive transcranial magnetic stimulation, collectingdata from those who experienced remission (defined as a HDRS scoreequal to or lower than 7. The patients were followed for up to 6 monthsafter treatment. Mean duration of remission for this cohort of patientswas 70.2 (± 58.4 days. Results: The only variable associated withthe duration of remission in the linear regression model was numberof repetitive transcranial magnetic stimulation sessions. Conclusion:Our findings suggest that the greater the number of sessions, the longerthe duration of repetitive transcranial magnetic stimulation effects.Consequently, future research investigating the effects of repetitivetranscranial magnetic stimulation should explore this variable in orderto maximize the therapeutic effects of this new brain stimulationtechnique.

  10. Evidence-based guidelines on the therapeutic use of repetitive transcranial magnetic stimulation (rTMS)

    DEFF Research Database (Denmark)

    Lefaucheur, Jean-Pascal; André-Obadia, Nathalie; Antal, Andrea

    2014-01-01

    A group of European experts was commissioned to establish guidelines on the therapeutic use of repetitive transcranial magnetic stimulation (rTMS) from evidence published up until March 2014, regarding pain, movement disorders, stroke, amyotrophic lateral sclerosis, multiple sclerosis, epilepsy...

  11. Transduction of Repetitive Mechanical Stimuli by Piezo1 and Piezo2 Ion Channels

    Directory of Open Access Journals (Sweden)

    Amanda H. Lewis

    2017-06-01

    Full Text Available Several cell types experience repetitive mechanical stimuli, including vein endothelial cells during pulsating blood flow, inner ear hair cells upon sound exposure, and skin cells and their innervating dorsal root ganglion (DRG neurons when sweeping across a textured surface or touching a vibrating object. While mechanosensitive Piezo ion channels have been clearly implicated in sensing static touch, their roles in transducing repetitive stimulations are less clear. Here, we perform electrophysiological recordings of heterologously expressed mouse Piezo1 and Piezo2 responding to repetitive mechanical stimulations. We find that both channels function as pronounced frequency filters whose transduction efficiencies vary with stimulus frequency, waveform, and duration. We then use numerical simulations and human disease-related point mutations to demonstrate that channel inactivation is the molecular mechanism underlying frequency filtering and further show that frequency filtering is conserved in rapidly adapting mouse DRG neurons. Our results give insight into the potential contributions of Piezos in transducing repetitive mechanical stimuli.

  12. Garnet composite films with Au particles fabricated by repetitive formation for enhancement of Faraday effect

    Energy Technology Data Exchange (ETDEWEB)

    Uchida, H; Nakai, Y [Department of Electronics and Intelligent Systems, Tohoku Institute of Technology, 35-1 Yagiyama-Kasumi, Taihaku, Sendai, Miyagi 982-8577 (Japan); Mizutani, Y; Inoue, M [Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Tempaku, Toyohashi, Aichi 441-8580 (Japan); Fedyanin, A A, E-mail: uchida_hn@tohtech.ac.jp [Faculty of Physics, Moscow State University, Moscow 119992 (Russian Federation)

    2011-02-16

    To prepare garnet (Bi : YIG) composite films with Au particles, we used a repetitive formation method to increase the number density of particles. On increasing the number of repetitions, the diameter distribution of the particles changed. After five repetitions using 5 nm Au films, the diameter distribution separated into two size groups. Shift of wavelength-excited localized surface plasmon resonance is discussed relative to the diameter distribution. In the composite films, enhancement of Faraday rotation associated with surface plasmons was observed. With six repetitions, a maximum enhanced rotation of -1.2{sup 0} was obtained, which is 20 times larger than that of a single Bi : YIG film. The figures of merit for the composite films are discussed. The thickness of a Bi : YIG composite film working for enhanced Faraday rotation was examined using an ion milling method.

  13. Restricted and repetitive behaviours, sensory processing and cognitive style in children with autism spectrum disorders.

    Science.gov (United States)

    Chen, Yu-Han; Rodgers, Jacqui; McConachie, Helen

    2009-04-01

    Many individuals with autism tend to focus on details. It has been suggested that this cognitive style may underlie the presence of stereotyped routines, repetitive interests and behaviours, and both relate in some way to sensory abnormalities. Twenty-nine children with diagnosis of high functioning autism or Asperger syndrome completed the Embedded Figures Test (EFT), and their parents the Short Sensory Profile and Childhood Routines Inventory. Significant correlations were found between degree of sensory abnormalities and amount of restricted and repetitive behaviours reported. Repetitive behaviours, age and IQ significantly predicted completion time on the EFT. The results suggest a cognitive link between an individual's detail-focused cognitive style and their repetitiveness. No such relationship was found with sensory processing abnormalities, which may arise at a more peripheral level of functioning.

  14. DC high voltage to drive helium plasma jet comprised of repetitive streamer breakdowns

    CERN Document Server

    Wang, Xingxing

    2016-01-01

    This paper demonstrates and studies helium atmospheric pressure plasma jet comprised of series of repetitive streamer breakdowns, which is driven by a pure DC high voltage (auto-oscillations). Repetition frequency of the breakdowns is governed by the geometry of discharge electrodes/surroundings and gas flow rate. Each next streamer is initiated when the electric field on the anode tip recovers after the previous breakdown and reaches the breakdown threshold value of about 2.5 kV/cm. Repetition frequency of the streamer breakdowns excited using this principle can be simply tuned by reconfiguring the discharge electrode geometry. This custom-designed type of the helium plasma jet, which operates on the DC high voltage and is comprised of the series of the repetitive streamer breakdowns at frequency about 13 kHz, is demonstrated.

  15. Repetition rate tunable ultra-short optical pulse generation based on electrical pattern generator

    Institute of Scientific and Technical Information of China (English)

    Xin Fu; Hongming Zhang; Meng Yan; Minyu Yao

    2009-01-01

    @@ An actively mode-locked laser with tunable repetition rate is proposed and experimentally demonstrated based on a programmable electrical pattern generator.By changing the repetition rate of the electrical patterns applied on the in-cavity modulator, the repetition rate of the output optical pulse sequences changes accordingly while the pulse width of the optical pulse train remains almost constant.In other words, the output ultra-short pulse train has a tunable duty cycle.In a proof-of-principle experiment, optical pulses with repetition rates of 10, 5, 2.5 and 1.25 GHz are obtained by adjusting the electrical pattern applied on the in-cavity modulator while their pulse widths remain almost unchanged.

  16. Widespread Chromatin Accessibility at Repetitive Elements Links Stem Cells with Human Cancer

    Directory of Open Access Journals (Sweden)

    Nicholas C. Gomez

    2016-11-01

    Full Text Available Chromatin regulation is critical for differentiation and disease. However, features linking the chromatin environment of stem cells with disease remain largely unknown. We explored chromatin accessibility in embryonic and multipotent stem cells and unexpectedly identified widespread chromatin accessibility at repetitive elements. Integrating genomic and biochemical approaches, we demonstrate that these sites of increased accessibility are associated with well-positioned nucleosomes marked by distinct histone modifications. Differentiation is accompanied by chromatin remodeling at repetitive elements associated with altered expression of genes in relevant developmental pathways. Remarkably, we found that the chromatin environment of Ewing sarcoma, a mesenchymally derived tumor, is shared with primary mesenchymal stem cells (MSCs. Accessibility at repetitive elements in MSCs offers a permissive environment that is exploited by the critical oncogene responsible for this cancer. Our data demonstrate that stem cells harbor a unique chromatin landscape characterized by accessibility at repetitive elements, a feature associated with differentiation and oncogenesis.

  17. Schistosome satellite DNA encodes active hammerhead ribozymes.

    Science.gov (United States)

    Ferbeyre, G; Smith, J M; Cedergren, R

    1998-07-01

    Using a computer program designed to search for RNA structural motifs in sequence databases, we have found a hammerhead ribozyme domain encoded in the Smalpha repetitive DNA of Schistosoma mansoni. Transcripts of these repeats are expressed as long multimeric precursor RNAs that cleave in vitro and in vivo into unit-length fragments. This RNA domain is able to engage in both cis and trans cleavage typical of the hammerhead ribozyme. Further computer analysis of S. mansoni DNA identified a potential trans cleavage site in the gene coding for a synaptobrevin-like protein, and RNA transcribed from this gene was efficiently cleaved by the Smalpha ribozyme in vitro. Similar families of repeats containing the hammerhead domain were found in the closely related Schistosoma haematobium and Schistosomatium douthitti species but were not present in Schistosoma japonicum or Heterobilharzia americana, suggesting that the hammerhead domain was not acquired from a common schistosome ancestor.

  18. DNA nanostructure immobilization to lithographic DNA arrays

    Science.gov (United States)

    Negrete, Omar D.

    Although DNA is well known for its genetic role in biology, DNA has also been sought-after as a material for the self-assembly of biological and electronic devices. Examples of DNA nanostructure construction include DNA tiled self-assembly and DNA Origami, where by controlling the sequence and concentration of DNA molecules, the rational design of geometric DNA nanostructures is possible. The assembly of DNA nanostructures takes place in solution and thus they are in disorder and require further organization to construct circuitry or devices. Hence, it is essential for future applications of this technology to develop methods to direct the placement of DNA nanostructures on a surface. To address this challenge my research examines the use of DNA microarrays to capture DNA nanostructures via DNA hybridization. Modern DNA arrays offer a high-density of sequence-specific molecular recognition sites where the addressable placement of DNA nanostructures can be achieved. Using Maskless Array Synthesizer (MAS) technology, I have characterized photolithographic DNA arrays for the hybridization of DNA complexes like large DNA molecules (> 1 kb), DNA-gold nanoparticle conjugates, and DNA Origami. Although modern photolithographic DNA arrays can possess a high-density of sequence (106/cm2), the printed DNA areas are on the order of tens of microns. Thus, I have also developed a method to reduce the DNA array spot size to nanoscale dimensions through the combined use of electron beam lithography with photolithographic DNA synthesis. This work addresses the key elements towards developing a surface patterning technology that takes advantage of DNA base-pairing for both molecular sub-assembly and surface patterning.

  19. Bilingual performance on nonword repetition in Spanish and English.

    Science.gov (United States)

    Summers, Connie; Bohman, Thomas M; Gillam, Ronald B; Peña, Elizabeth D; Bedore, Lisa M

    2010-01-01

    Nonword repetition (NWR) involves the ability to perceive, store, recall and reproduce phonological sequences. These same abilities play a role in word and morpheme learning. Cross-linguistic studies of performance on NWR tasks, word learning, and morpheme learning yield patterns of increased performance on all three tasks as a function of age and language experience. These results are consistent with the idea that there may be universal information-processing mechanisms supporting language learning. Because bilingual children's language experience is divided across two languages, studying performance in two languages on NWR could inform one's understanding of the relationship between information processing and language learning. The primary aims of this study were to compare bilingual language learners' recall of Spanish-like and English-like items on NWR tasks and to assess the relationships between performance on NWR, semantics, and morphology tasks. Sixty-two Hispanic children exposed to English and Spanish were recruited from schools in central Texas, USA. Their parents reported on the children's input and output in both languages. The children completed NWR tasks and short tests of semantics and morphosyntax in both languages. Mixed-model analysis of variance was used to explore direct effects and interactions between the variables of nonword length, language experience, language outcome measures, and cumulative exposure on NWR performance. Children produced the Spanish-like nonwords more accurately than the English-like nonwords. NWR performance was significantly correlated to cumulative language experience in both English and Spanish. There were also significant correlations between NWR and morphosyntax but not semantics. Language knowledge appears to play a role in the task of NWR. The relationship between performance on morphosyntax and NWR tasks indicates children rely on similar language-learning mechanisms to mediate these tasks. More exposure to

  20. Risk of repetition of suicide attempt, suicide or all deaths after an episode of attempted suicide

    DEFF Research Database (Denmark)

    Christiansen, Erik; Jensen, Børge Frank

    2007-01-01

    This study was undertaken in order to estimate the incidence of repetition of suicide attempt, suicide and all deaths, and to analyse the influence of psychiatric illness and socio-demographic factors on these.......This study was undertaken in order to estimate the incidence of repetition of suicide attempt, suicide and all deaths, and to analyse the influence of psychiatric illness and socio-demographic factors on these....