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Sample records for 14-bp inverted repeat

  1. Isolation and characterization of a novel family (Mild-4) of miniature subterminal inverted repeat transposable element from the Colorado potato beetle, Leptinotarsa decemlineata

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Determining the genomic structure of DAT-2 and -3 led to the isolation of four novel families of miniature subterminal inverted repeat transposable elements (MSITE): Mild-1, -2, -3 and -4. Mild-1a is inserted within the first intron of diapause protein-1. Mild-1a is 284 bp in length, has a 14 bp tar...

  2. Origin-Dependent Inverted-Repeat Amplification: Tests of a Model for Inverted DNA Amplification

    PubMed Central

    Brewer, Bonita J.; Payen, Celia; Di Rienzi, Sara C.; Higgins, Megan M.; Ong, Giang; Dunham, Maitreya J.; Raghuraman, M. K.

    2015-01-01

    DNA replication errors are a major driver of evolution—from single nucleotide polymorphisms to large-scale copy number variations (CNVs). Here we test a specific replication-based model to explain the generation of interstitial, inverted triplications. While no genetic information is lost, the novel inversion junctions and increased copy number of the included sequences create the potential for adaptive phenotypes. The model—Origin-Dependent Inverted-Repeat Amplification (ODIRA)—proposes that a replication error at pre-existing short, interrupted, inverted repeats in genomic sequences generates an extrachromosomal, inverted dimeric, autonomously replicating intermediate; subsequent genomic integration of the dimer yields this class of CNV without loss of distal chromosomal sequences. We used a combination of in vitro and in vivo approaches to test the feasibility of the proposed replication error and its downstream consequences on chromosome structure in the yeast Saccharomyces cerevisiae. We show that the proposed replication error—the ligation of leading and lagging nascent strands to create “closed” forks—can occur in vitro at short, interrupted inverted repeats. The removal of molecules with two closed forks results in a hairpin-capped linear duplex that we show replicates in vivo to create an inverted, dimeric plasmid that subsequently integrates into the genome by homologous recombination, creating an inverted triplication. While other models have been proposed to explain inverted triplications and their derivatives, our model can also explain the generation of human, de novo, inverted amplicons that have a 2:1 mixture of sequences from both homologues of a single parent—a feature readily explained by a plasmid intermediate that arises from one homologue and integrates into the other homologue prior to meiosis. Our tests of key features of ODIRA lend support to this mechanism and suggest further avenues of enquiry to unravel the origins of

  3. Inverted repeats: computer analysis of microorganism genome and imaging of cruciform structure in DNA by atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Limansky, Alex; Limanskaya, Olga Y.

    2003-04-01

    Inverted repeats may regulate genetic procceses by formation of hairpin secondary structures that block DNA polymerases. Two different DNA conformations may cor-respond to inverted repeats: either a linear double stranded helix or a cruciform struc-ture consisting of two symmetrical hairpins. Theoretical and experimental studies have shown that cruciform structures can exist in negatively supercoiled DNA, cont-rary to relaxed molecules. Cruciform formation depends on many factors, firstly, on temperature and supercoils density. Recently application of the scanning probe mic-roscopy has allowed for significant progress in cruciform structure studies. The goal of present work is computer analysis of inverted repeats in viruses, bac-teria and plasmid DNA (human immunodeficiency virus (HIV), bovine immunode-ficiency virus (BIV), bovine leukemia virus (BLV), mycobacterium tuberculosis (MTB), plasmid pUC8) and direct visualization of the cruciform structure in super-coiled DNA by atomic force microscopy (AFM). The cruciform dimensions were determined. Analysis and modeling of the most thermodynamically stable cruciform formations in viral and bacterial DNA were carried out. The complete genome sequence of HIV, BIV, BLV is ~9000 base pairs (bp), my-cobacterium tuberculosis - over 4000000 bp, pUC8 DNA - 2665 bp. Computer ana-lysis showed that two different isolates of MTB with complete genome contain 45 and 50 inverted repeats; HIV, BIV, BLV and plasmid pUC8 contain only one palin-drome which can form cruciform structure in buffer solution. Cruciform in plasmid pUC8 supercoiled DNA, was directly visualized by atomic force microscopy. Cruciform is seen as clear-cut extrusions on the DNA filaments with the lengths of the arms fully consistent with the size of the hairpins expected from a 26 bp inverted repeat in pUC8 plasmid DNA. Application of the aminomodi-fied mica allowed to obtain stable DNA images. DNA molecules on aminomica are not stretched and their contours are

  4. Inverted repeats in the promoter as an autoregulatory sequence for TcrX in Mycobacterium tuberculosis

    SciTech Connect

    Bhattacharya, Monolekha; Das, Amit Kumar

    2011-11-11

    Highlights: Black-Right-Pointing-Pointer The regulatory sequences recognized by TcrX have been identified. Black-Right-Pointing-Pointer The regulatory region comprises of inverted repeats segregated by 30 bp region. Black-Right-Pointing-Pointer The mode of binding of TcrX with regulatory sequence is unique. Black-Right-Pointing-Pointer In silico TcrX-DNA docked model binds one of the inverted repeats. Black-Right-Pointing-Pointer Both phosphorylated and unphosphorylated TcrX binds regulatory sequence in vitro. -- Abstract: TcrY, a histidine kinase, and TcrX, a response regulator, constitute a two-component system in Mycobacterium tuberculosis. tcrX, which is expressed during iron scarcity, is instrumental in the survival of iron-dependent M. tuberculosis. However, the regulator of tcrX/Y has not been fully characterized. Crosslinking studies of TcrX reveal that it can form oligomers in vitro. Electrophoretic mobility shift assays (EMSAs) show that TcrX recognizes two regions in the promoter that are comprised of inverted repeats separated by {approx}30 bp. The dimeric in silico model of TcrX predicts binding to one of these inverted repeat regions. Site-directed mutagenesis and radioactive phosphorylation indicate that D54 of TcrX is phosphorylated by H256 of TcrY. However, phosphorylated and unphosphorylated TcrX bind the regulatory sequence with equal efficiency, which was shown with an EMSA using the D54A TcrX mutant.

  5. Detection and characterization of miniature inverted-repeat transposable elements in “Candidatus Liberibacter asiaticus”

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Miniature inverted-repeat transposable elements (MITEs) are non-autonomous transposons (devoid a transposase gene, tps) involving insertion/deletion of genomic DNA in bacterial genomes influencing gene functions. No transposon has yet been reported in “Candidatus Liberibacter asiaticus”, an alpha-pr...

  6. Mutagenic Inverted Repeats Assisted Genome Engineering (MIRAGE) in Saccharomyces cerevisiae: deletion of gal7.

    PubMed

    Nair, Nikhil U; Zhao, Huimin

    2012-01-01

    MIRAGE is a unique in vivo genome editing technique that exploits the inherent instability of inverted repeats (palindromes) in the Saccharomyces cerevisiae chromosome. As a technique able to quickly create deletions as well as precise point mutations, it is valuable in applications that require creation of designer strains of this yeast. In particular, it has various potential applications in metabolic engineering, systems biology, synthetic biology, and molecular genetics. PMID:22144353

  7. Formation of large palindromic DNA by homologous recombination of short inverted repeat sequences in Saccharomyces cerevisiae.

    PubMed Central

    Butler, David K; Gillespie, David; Steele, Brandi

    2002-01-01

    Large DNA palindromes form sporadically in many eukaryotic and prokaryotic genomes and are often associated with amplified genes. The presence of a short inverted repeat sequence near a DNA double-strand break has been implicated in the formation of large palindromes in a variety of organisms. Previously we have established that in Saccharomyces cerevisiae a linear DNA palindrome is efficiently formed from a single-copy circular plasmid when a DNA double-strand break is introduced next to a short inverted repeat sequence. In this study we address whether the linear palindromes form by an intermolecular reaction (that is, a reaction between two identical fragments in a head-to-head arrangement) or by an unusual intramolecular reaction, as it apparently does in other examples of palindrome formation. Our evidence supports a model in which palindromes are primarily formed by an intermolecular reaction involving homologous recombination of short inverted repeat sequences. We have also extended our investigation into the requirement for DNA double-strand break repair genes in palindrome formation. We have found that a deletion of the RAD52 gene significantly reduces palindrome formation by intermolecular recombination and that deletions of two other genes in the RAD52-epistasis group (RAD51 and MRE11) have little or no effect on palindrome formation. In addition, palindrome formation is dramatically reduced by a deletion of the nucleotide excision repair gene RAD1. PMID:12136011

  8. detectIR: a novel program for detecting perfect and imperfect inverted repeats using complex numbers and vector calculation.

    PubMed

    Ye, Congting; Ji, Guoli; Li, Lei; Liang, Chun

    2014-01-01

    Inverted repeats are present in abundance in both prokaryotic and eukaryotic genomes and can form DNA secondary structures--hairpins and cruciforms that are involved in many important biological processes. Bioinformatics tools for efficient and accurate detection of inverted repeats are desirable, because existing tools are often less accurate and time consuming, sometimes incapable of dealing with genome-scale input data. Here, we present a MATLAB-based program called detectIR for the perfect and imperfect inverted repeat detection that utilizes complex numbers and vector calculation and allows genome-scale data inputs. A novel algorithm is adopted in detectIR to convert the conventional sequence string comparison in inverted repeat detection into vector calculation of complex numbers, allowing non-complementary pairs (mismatches) in the pairing stem and a non-palindromic spacer (loop or gaps) in the middle of inverted repeats. Compared with existing popular tools, our program performs with significantly higher accuracy and efficiency. Using genome sequence data from HIV-1, Arabidopsis thaliana, Homo sapiens and Zea mays for comparison, detectIR can find lots of inverted repeats missed by existing tools whose outputs often contain many invalid cases. detectIR is open source and its source code is freely available at: https://sourceforge.net/projects/detectir. PMID:25409465

  9. detectIR: A Novel Program for Detecting Perfect and Imperfect Inverted Repeats Using Complex Numbers and Vector Calculation

    PubMed Central

    Ye, Congting; Ji, Guoli; Li, Lei; Liang, Chun

    2014-01-01

    Inverted repeats are present in abundance in both prokaryotic and eukaryotic genomes and can form DNA secondary structures – hairpins and cruciforms that are involved in many important biological processes. Bioinformatics tools for efficient and accurate detection of inverted repeats are desirable, because existing tools are often less accurate and time consuming, sometimes incapable of dealing with genome-scale input data. Here, we present a MATLAB-based program called detectIR for the perfect and imperfect inverted repeat detection that utilizes complex numbers and vector calculation and allows genome-scale data inputs. A novel algorithm is adopted in detectIR to convert the conventional sequence string comparison in inverted repeat detection into vector calculation of complex numbers, allowing non-complementary pairs (mismatches) in the pairing stem and a non-palindromic spacer (loop or gaps) in the middle of inverted repeats. Compared with existing popular tools, our program performs with significantly higher accuracy and efficiency. Using genome sequence data from HIV-1, Arabidopsis thaliana, Homo sapiens and Zea mays for comparison, detectIR can find lots of inverted repeats missed by existing tools whose outputs often contain many invalid cases. detectIR is open source and its source code is freely available at: https://sourceforge.net/projects/detectir. PMID:25409465

  10. Insights on genome size evolution from a miniature inverted repeat transposon driving a satellite DNA.

    PubMed

    Scalvenzi, Thibault; Pollet, Nicolas

    2014-12-01

    The genome size in eukaryotes does not correlate well with the number of genes they contain. We can observe this so-called C-value paradox in amphibian species. By analyzing an amphibian genome we asked how repetitive DNA can impact genome size and architecture. We describe here our discovery of a Tc1/mariner miniature inverted-repeat transposon family present in Xenopus frogs. These transposons named miDNA4 are unique since they contain a satellite DNA motif. We found that miDNA4 measured 331 bp, contained 25 bp long inverted terminal repeat sequences and a sequence motif of 119 bp present as a unique copy or as an array of 2-47 copies. We characterized the structure, dynamics, impact and evolution of the miDNA4 family and its satellite DNA in Xenopus frog genomes. This led us to propose a model for the evolution of these two repeated sequences and how they can synergize to increase genome size. PMID:25193611

  11. Detection and Characterization of Miniature Inverted-Repeat Transposable Elements in “Candidatus Liberibacter asiaticus”

    PubMed Central

    Wang, Xuefeng; Tan, Jin; Bai, Ziqin; Su, Huanan; Deng, Xiaoling; Li, Zhongan

    2013-01-01

    Miniature inverted-repeat transposable elements (MITEs) are nonautonomous transposons (devoid of the transposase gene tps) that affect gene functions through insertion/deletion events. No transposon has yet been reported to occur in “Candidatus Liberibacter asiaticus,” an alphaproteobacterium associated with citrus Huanglongbing (HLB, yellow shoot disease). In this study, two MITEs, MCLas-A and MCLas-B, in “Ca. Liberibacter asiaticus” were detected, and the genome was characterized using 326 isolates collected in China and Florida. MCLas-A had three variants, ranging from 237 to 325 bp, and was inserted into a TTTAGG site of a prophage region. MCLas-A had a pair of 54-bp terminal inverted repeats (TIRs), which contained three tandem repeats of TGGTAACCAC. Both “filled” (with MITE) and “empty” (without MITE) states were detected, suggesting the MITE mobility. The empty sites of all bacterial isolates had TIR tandem repeat remnants (TRR). Frequencies of TRR types varied according to geographical origins. MCLas-B had four variants, ranging from 238 to 250 bp, and was inserted into a TA site of another “Ca. Liberibacter” prophage. The MITE, MCLas-B, had a pair of 23-bp TIRs containing no tandem repeats. No evidence of MCLas-B mobility was found. An identical open reading frame was found upstream of MCLas-A (229 bp) and MCLas-B (232 bp) and was predicted to be a putative tps, suggesting an in cis tps-MITE configuration. MCLas-A and MCLas-B were predominantly copresent in Florida isolates, whereas MCLas-A alone or MCLas-B alone was found in Chinese isolates. PMID:23813735

  12. Efficiency of gene silencing in Arabidopsis: direct inverted repeats vs. transitive RNAi vectors.

    SciTech Connect

    Filichkin, Sergei A; DiFazio, Steven P; Brunner, Amy M; Davis, John M; Yang, Zamin Koo; Kalluri, Udaya C; Arias, Renee S; Etherington, Elizabeth; Tuskan, Gerald A; Strauss, S

    2007-01-01

    We investigated the efficiency of RNA interference (RNAi) in Arabidopsis using transitive and homologous inverted repeat (hIR) vectors. hIR constructs carry self-complementary intron-spliced fragments of the target gene whereas transitive vectors have the target sequence fragment adjacent to an intron-spliced, inverted repeat of heterologous origin. Both transitive and hIR constructs facilitated specific and heritable silencing in the three genes studied (AP1, ETTIN and TTG1). Both types of vectors produced a phenotypic series that phenocopied reduction of function mutants for the respective target gene. The hIR yielded up to fourfold higher proportions of events with strongly manifested reduction of function phenotypes compared to transitive RNAi. We further investigated the efficiency and potential off-target effects of AP1 silencing by both types of vectors using genome-scale microarrays and quantitative RT-PCR. The depletion of AP1 transcripts coincided with reduction of function phenotypic changes among both hIR and transitive lines and also showed similar expression patterns among differentially regulated genes. We did not detect significant silencing directed against homologous potential off-target genes when constructs were designed with minimal sequence similarity. Both hIR and transitive methods are useful tools in plant biotechnology and genomics. The choice of vector will depend on specific objectives such as cloning throughput, number of events and degree of suppression required.

  13. Nezha, a novel active miniature inverted-repeat transposable element in cyanobacteria

    SciTech Connect

    Zhou Fengfeng; Tran Thao; Xu Ying

    2008-01-25

    Miniature inverted-repeat transposable elements (MITEs) were first identified in plants and exerted extensive proliferations throughout eukaryotic and archaeal genomes. But very few MITEs have been characterized in bacteria. We identified a novel MITE, called Nezha, in cyanobacteria Anabaena variabilis ATCC 29413 and Nostoc sp. PCC 7120. Nezha, like most previously known MITEs in other organisms, is small in size, non-coding, carrying TIR and DR signals, and of potential to form a stable RNA secondary structure, and it tends to insert into A+T-rich regions. Recent transpositions of Nezha were observed in A. variabilis ATCC 29413 and Nostoc sp. PCC 7120, respectively. Nezha might have proliferated recently with aid from the transposase encoded by ISNpu3-like elements. A possible horizontal transfer event of Nezha from cyanobacteria to Polaromonas JS666 is also observed.

  14. Characterization of active miniature inverted-repeat transposable elements in the peanut genome.

    PubMed

    Shirasawa, Kenta; Hirakawa, Hideki; Tabata, Satoshi; Hasegawa, Makoto; Kiyoshima, Hiroyuki; Suzuki, Sigeru; Sasamoto, Sigemi; Watanabe, Akiko; Fujishiro, Tsunakazu; Isobe, Sachiko

    2012-05-01

    Miniature inverted-repeat transposable elements (MITEs), some of which are known as active nonautonomous DNA transposons, are found in the genomes of plants and animals. In peanut (Arachis hypogaea), Ah-MITE1 has been identified in a gene for fatty-acid desaturase, and possessed excision activity. However, the AhMITE1 distribution and frequency of excision have not been determined for the peanut genome. In order to characterize AhMITE1s, their genomic diversity and transposition ability was investigated. Southern blot analysis indicated high AhMITE1 copy number in the genomes of A. hypogaea, A. magna and A. monticola, but not in A. duranensis. A total of 504 AhMITE1s were identified from the MITE-enriched genomic libraries of A. hypogaea. The representative AhMITE1s exhibited a mean length of 205.5 bp and a GC content of 30.1%, with AT-rich, 9 bp target site duplications and 25 bp terminal inverted repeats. PCR analyses were performed using primer pairs designed against both flanking sequences of each AhMITE1. These analyses detected polymorphisms at 169 out of 411 insertional loci in the four peanut lines. In subsequent analyses of 60 gamma-irradiated mutant lines, four Ah-MITE1 excisions showed footprint mutations at the 109 loci tested. This study characterizes AhMITE1s in peanut and discusses their use as DNA markers and mutagens for the genetics, genomics and breeding of peanut and its relatives. PMID:22294450

  15. Structure and organization of Marchantia polymorpha chloroplast genome. IV. Inverted repeat and small single copy regions.

    PubMed

    Kohchi, T; Shirai, H; Fukuzawa, H; Sano, T; Komano, T; Umesono, K; Inokuchi, H; Ozeki, H; Ohyama, K

    1988-09-20

    We characterized the genes in the regions of large inverted repeats (IRA and IRB, 10,058 base-pairs each) and a small single copy (SSC 19,813 bp) of chloroplast DNA from Marchantia polymorpha. The inverted repeat (IR) regions contain genes for four ribosomal RNAs (16 S, 23 S, 4.5 S and 5 S rRNAs) and five transfer RNAs (valine tRNA(GAC), isoleucine tRNA(GAU), alanine tRNA(UGC), arginine tRNA(ACG) and asparagine tRNA(GUU)). The gene organization of the IR regions in the liverwort chloroplast genome is conserved, although the IR regions are smaller (10,058 base-pairs) than any reported in higher plant chloroplasts. The small single-copy region (19,813 base-pairs) encoded genes for 17 open reading frames, a leucine tRNA(UAG) and a proline tRNA(GGG)-like sequence. We identified 12 open reading frames by homology of their coding sequences to a 4Fe-4S-type ferredoxin protein, a bacterial nitrogenase reductase component (Fe-protein), five human mitochondrial components of NADH dehydrogenase (ND1, ND4, ND4L, ND5 and ND6), two Escherichia coli ribosomal proteins (S15 and L21), two putative proteins encoded in the kinetoplast maxicircle DNA of Leishmania tarentolae (LtORF 3 and LtORF 4), and a bacterial permease inner membrane component (encoded by malF in E. coli or hisQ in Salmonella typhimurium). PMID:3199437

  16. Centromeres of the Yeast Komagataella phaffii (Pichia pastoris) Have a Simple Inverted-Repeat Structure.

    PubMed

    Coughlan, Aisling Y; Hanson, Sara J; Byrne, Kevin P; Wolfe, Kenneth H

    2016-01-01

    Centromere organization has evolved dramatically in one clade of fungi, the Saccharomycotina. These yeasts have lost the ability to make normal eukaryotic heterochromatin with histone H3K9 methylation, which is a major component of pericentromeric regions in other eukaryotes. Following this loss, several different types of centromere emerged, including two types of sequence-defined ("point") centromeres, and the epigenetically defined "small regional" centromeres of Candida albicans Here we report that centromeres of the methylotrophic yeast Komagataella phaffii (formerly called Pichia pastoris) are structurally defined. Each of its four centromeres consists of a 2-kb inverted repeat (IR) flanking a 1-kb central core (mid) region. The four centromeres are unrelated in sequence. CenH3 (Cse4) binds strongly to the cores, with a decreasing gradient along the IRs. This mode of organization resembles Schizosaccharomyces pombe centromeres but is much more compact and lacks the extensive flanking heterochromatic otr repeats. Different isolates of K. phaffii show polymorphism for the orientation of the mid regions, due to recombination in the IRs. CEN4 is located within a 138-kb region that changes orientation during mating-type switching, but switching does not induce recombination of centromeric IRs. Our results demonstrate that evolutionary transitions in centromere organization have occurred in multiple yeast clades. PMID:27497317

  17. Genes Translocated into the Plastid Inverted Repeat Show Decelerated Substitution Rates and Elevated GC Content.

    PubMed

    Li, Fay-Wei; Kuo, Li-Yaung; Pryer, Kathleen M; Rothfels, Carl J

    2016-01-01

    Plant chloroplast genomes (plastomes) are characterized by an inverted repeat (IR) region and two larger single copy (SC) regions. Patterns of molecular evolution in the IR and SC regions differ, most notably by a reduced rate of nucleotide substitution in the IR compared to the SC region. In addition, the organization and structure of plastomes is fluid, and rearrangements through time have repeatedly shuffled genes into and out of the IR, providing recurrent natural experiments on how chloroplast genome structure can impact rates and patterns of molecular evolution. Here we examine four loci (psbA, ycf2, rps7, and rps12 exon 2-3) that were translocated from the SC into the IR during fern evolution. We use a model-based method, within a phylogenetic context, to test for substitution rate shifts. All four loci show a significant, 2- to 3-fold deceleration in their substitution rate following translocation into the IR, a phenomenon not observed in any other, nontranslocated plastid genes. Also, we show that after translocation, the GC content of the third codon position and of the noncoding regions is significantly increased, implying that gene conversion within the IR is GC-biased. Taken together, our results suggest that the IR region not only reduces substitution rates, but also impacts nucleotide composition. This finding highlights a potential vulnerability of correlating substitution rate heterogeneity with organismal life history traits without knowledge of the underlying genome structure. PMID:27401175

  18. Genes Translocated into the Plastid Inverted Repeat Show Decelerated Substitution Rates and Elevated GC Content

    PubMed Central

    Li, Fay-Wei; Kuo, Li-Yaung; Pryer, Kathleen M.; Rothfels, Carl J.

    2016-01-01

    Plant chloroplast genomes (plastomes) are characterized by an inverted repeat (IR) region and two larger single copy (SC) regions. Patterns of molecular evolution in the IR and SC regions differ, most notably by a reduced rate of nucleotide substitution in the IR compared to the SC region. In addition, the organization and structure of plastomes is fluid, and rearrangements through time have repeatedly shuffled genes into and out of the IR, providing recurrent natural experiments on how chloroplast genome structure can impact rates and patterns of molecular evolution. Here we examine four loci (psbA, ycf2, rps7, and rps12 exon 2–3) that were translocated from the SC into the IR during fern evolution. We use a model-based method, within a phylogenetic context, to test for substitution rate shifts. All four loci show a significant, 2- to 3-fold deceleration in their substitution rate following translocation into the IR, a phenomenon not observed in any other, nontranslocated plastid genes. Also, we show that after translocation, the GC content of the third codon position and of the noncoding regions is significantly increased, implying that gene conversion within the IR is GC-biased. Taken together, our results suggest that the IR region not only reduces substitution rates, but also impacts nucleotide composition. This finding highlights a potential vulnerability of correlating substitution rate heterogeneity with organismal life history traits without knowledge of the underlying genome structure. PMID:27401175

  19. detectMITE: A novel approach to detect miniature inverted repeat transposable elements in genomes.

    PubMed

    Ye, Congting; Ji, Guoli; Liang, Chun

    2016-01-01

    Miniature inverted repeat transposable elements (MITEs) are prevalent in eukaryotic genomes, including plants and animals. Classified as a type of non-autonomous DNA transposable elements, they play important roles in genome organization and evolution. Comprehensive and accurate genome-wide detection of MITEs in various eukaryotic genomes can improve our understanding of their origins, transposition processes, regulatory mechanisms, and biological relevance with regard to gene structures, expression, and regulation. In this paper, we present a new MATLAB-based program called detectMITE that employs a novel numeric calculation algorithm to replace conventional string matching algorithms in MITE detection, adopts the Lempel-Ziv complexity algorithm to filter out MITE candidates with low complexity, and utilizes the powerful clustering program CD-HIT to cluster similar MITEs into MITE families. Using the rice genome as test data, we found that detectMITE can more accurately, comprehensively, and efficiently detect MITEs on a genome-wide scale than other popular MITE detection tools. Through comparison with the potential MITEs annotated in Repbase, the widely used eukaryotic repeat database, detectMITE has been shown to find known and novel MITEs with a complete structure and full-length copies in the genome. detectMITE is an open source tool (https://sourceforge.net/projects/detectmite). PMID:26795595

  20. Replication stalling at unstable inverted repeats: Interplay between DNA hairpins and fork stabilizing proteins

    PubMed Central

    Voineagu, Irina; Narayanan, Vidhya; Lobachev, Kirill S.; Mirkin, Sergei M.

    2008-01-01

    DNA inverted repeats (IRs) are hotspots of genomic instability in both prokaryotes and eukaryotes. This feature is commonly attributed to their ability to fold into hairpin- or cruciform-like DNA structures interfering with DNA replication and other genetic processes. However, direct evidence that IRs are replication stall sites in vivo is currently lacking. Here, we show by 2D electrophoretic analysis of replication intermediates that replication forks stall at IRs in bacteria, yeast, and mammalian cells. We found that DNA hairpins, rather than DNA cruciforms, are responsible for the replication stalling by comparing the effects of specifically designed imperfect IRs with varying lengths of their central spacer. Finally, we report that yeast fork-stabilizing proteins, Tof1 and Mrc1, are required to counteract repeat-mediated replication stalling. We show that the function of the Tof1 protein at DNA structure-mediated stall sites is different from its previously described effect on protein-mediated replication fork barriers. PMID:18632578

  1. Centromeres of the Yeast Komagataella phaffii (Pichia pastoris) Have a Simple Inverted-Repeat Structure

    PubMed Central

    Coughlan, Aisling Y.; Hanson, Sara J.; Byrne, Kevin P.; Wolfe, Kenneth H.

    2016-01-01

    Centromere organization has evolved dramatically in one clade of fungi, the Saccharomycotina. These yeasts have lost the ability to make normal eukaryotic heterochromatin with histone H3K9 methylation, which is a major component of pericentromeric regions in other eukaryotes. Following this loss, several different types of centromere emerged, including two types of sequence-defined (“point”) centromeres, and the epigenetically defined “small regional” centromeres of Candida albicans. Here we report that centromeres of the methylotrophic yeast Komagataella phaffii (formerly called Pichia pastoris) are structurally defined. Each of its four centromeres consists of a 2-kb inverted repeat (IR) flanking a 1-kb central core (mid) region. The four centromeres are unrelated in sequence. CenH3 (Cse4) binds strongly to the cores, with a decreasing gradient along the IRs. This mode of organization resembles Schizosaccharomyces pombe centromeres but is much more compact and lacks the extensive flanking heterochromatic otr repeats. Different isolates of K. phaffii show polymorphism for the orientation of the mid regions, due to recombination in the IRs. CEN4 is located within a 138-kb region that changes orientation during mating-type switching, but switching does not induce recombination of centromeric IRs. Our results demonstrate that evolutionary transitions in centromere organization have occurred in multiple yeast clades. PMID:27497317

  2. Abundant Degenerate Miniature Inverted-Repeat Transposable Elements in Genomes of Epichloid Fungal Endophytes of Grasses

    PubMed Central

    Fleetwood, Damien J.; Khan, Anar K.; Johnson, Richard D.; Young, Carolyn A.; Mittal, Shipra; Wrenn, Ruth E.; Hesse, Uljana; Foster, Simon J.; Schardl, Christopher L.; Scott, Barry

    2011-01-01

    Miniature inverted-repeat transposable elements (MITEs) are abundant repeat elements in plant and animal genomes; however, there are few analyses of these elements in fungal genomes. Analysis of the draft genome sequence of the fungal endophyte Epichloë festucae revealed 13 MITE families that make up almost 1% of the E. festucae genome, and relics of putative autonomous parent elements were identified for three families. Sequence and DNA hybridization analyses suggest that at least some of the MITEs identified in the study were active early in the evolution of Epichloë but are not found in closely related genera. Analysis of MITE integration sites showed that these elements have a moderate integration site preference for 5′ genic regions of the E. festucae genome and are particularly enriched near genes for secondary metabolism. Copies of the EFT-3m/Toru element appear to have mediated recombination events that may have abolished synthesis of two fungal alkaloids in different epichloae. This work provides insight into the potential impact of MITEs on epichloae evolution and provides a foundation for analysis in other fungal genomes. PMID:21948396

  3. detectMITE: A novel approach to detect miniature inverted repeat transposable elements in genomes

    PubMed Central

    Ye, Congting; Ji, Guoli; Liang, Chun

    2016-01-01

    Miniature inverted repeat transposable elements (MITEs) are prevalent in eukaryotic genomes, including plants and animals. Classified as a type of non-autonomous DNA transposable elements, they play important roles in genome organization and evolution. Comprehensive and accurate genome-wide detection of MITEs in various eukaryotic genomes can improve our understanding of their origins, transposition processes, regulatory mechanisms, and biological relevance with regard to gene structures, expression, and regulation. In this paper, we present a new MATLAB-based program called detectMITE that employs a novel numeric calculation algorithm to replace conventional string matching algorithms in MITE detection, adopts the Lempel-Ziv complexity algorithm to filter out MITE candidates with low complexity, and utilizes the powerful clustering program CD-HIT to cluster similar MITEs into MITE families. Using the rice genome as test data, we found that detectMITE can more accurately, comprehensively, and efficiently detect MITEs on a genome-wide scale than other popular MITE detection tools. Through comparison with the potential MITEs annotated in Repbase, the widely used eukaryotic repeat database, detectMITE has been shown to find known and novel MITEs with a complete structure and full-length copies in the genome. detectMITE is an open source tool (https://sourceforge.net/projects/detectmite). PMID:26795595

  4. Mobilization and evolutionary history of miniature inverted-repeat transposable elements (MITEs) in Beta vulgaris L.

    PubMed

    Menzel, Gerhard; Dechyeva, Daryna; Keller, Heiko; Lange, Cornelia; Himmelbauer, Heinz; Schmidt, Thomas

    2006-01-01

    We have identified three families of miniature inverted-repeat transposable elements (VulMITEs) in the genome of sugar beet (Beta vulgaris L.), evidently derived from a member of the Vulmar family of mariner transposons. While VulMITEs I are typical stowaway-like MITEs, VulMITEs II and VulMITEs III are rearranged stowaway elements of increased size. The integration of divergent moderately and highly repetitive sequences into VulMITEs II and, in particular in VulMITEs III, respectively, shows that amplification of repetitive DNA by MITEs contribute to the increase of genome size with possible implications for plant genome evolution. Fluorescent in-situ hybridization (FISH), for the first time visualizing stowaway MITE distribution on plant chromosomes, revealed a dispersed localization of VulMITEs along all B. vulgaris chromosomes. Analysis of the flanking sequences identified a dispersed repeat as target site for the integration of the stowaway element VulMITE I. Recent transposition of VulMITE I, which most likely occurred during the domestication of cultivated beets, was concluded from insertional polymorphisms between different B. vulgaris cultivars and species. PMID:17171577

  5. terMITEs: miniature inverted-repeat transposable elements (MITEs) in the termite genome (Blattodea: Termitoidae).

    PubMed

    Luchetti, Andrea

    2015-08-01

    Transposable elements (TEs) are discrete DNA sequences which are able to replicate and jump into different genomic locations. Miniature inverted-repeats TEs (MITEs) are non-autonomous DNA elements whose origin is still poorly understood. Recently, some MITEs were found to contain core repeats that can be arranged in tandem arrays; in some instances, these arrays have even given rise to satellite DNAs in the (peri)centromeric region of the host chromosomes. I report the discovery and analysis of three new MITEs found in the genome of several termite species (hence the name terMITEs) in two different families. For two of the MITEs (terMITE1-Tc1/mariner superfamily; terMITE2-piggyBac superfamily), evidence of past mobility was retrieved. Moreover, these two MITEs contained core repeats, 16 bp and 114 bp long respectively, exhibiting copy number variation. In terMITE2, the tandem duplication appeared associated with element degeneration, in line with a recently proposed evolutionary model on MITEs and the origin of tandem arrays. Concerning their genomic distribution, terMITE1 and terMITE3 appeared more frequently inserted close to coding regions while terMITE2 was mostly associated with TEs. Although MITEs are commonly distributed in coding regions, terMITE2 distribution is in line with that of other insects' piggyBac-related elements and of other small TEs found in termite genomes. This has been explained through insertional preference rather than through selective processes. Data presented here add to the knowledge on the poorly exploited polyneopteran genomes and will provide an interesting framework in which to study TEs' evolution and host's life history traits. PMID:25711308

  6. Inverted repeats and genome architecture conversions of terrestrial isopods mitochondrial DNA.

    PubMed

    Doublet, Vincent; Helleu, Quentin; Raimond, Roland; Souty-Grosset, Catherine; Marcadé, Isabelle

    2013-09-01

    Mitochondrial DNA (mtDNA) is usually depicted as a circular molecule, however, there is increasing evidence that linearization of mtDNA evolved independently many times in organisms such as fungi, unicellular eukaryotes, and animals. Recent observations in various models with linear mtDNA revealed the presence of conserved inverted repeats (IR) at both ends that, when they become single-stranded, may be able to fold on themselves to create telomeric-hairpins involved in genome architecture conversions. The atypical mtDNA of terrestrial isopods (Crustacea: Oniscidea) composed of linear monomers and circular dimers is an interesting model to study genome architecture conversions. Here, we present the mtDNA control region sequences of two species of the genus Armadillidium: A. vulgare and A. pelagicum. All features of arthropods mtDNA control regions are present (origin of replication, poly-T stretch, GA and TA-rich blocks and one variable domain), plus a conserved IR. This IR can potentially fold into a hairpin structure and is present in two different orientations among the A. vulgare populations: either in one sense or in its reverse complement. This polymorphism, also observed in a single individual (heteroplasmy), might be a signature of genome architecture conversions from linear to circular monomeric mtDNA via successive opening and closing of the molecules. PMID:24068302

  7. P-MITE: a database for plant miniature inverted-repeat transposable elements.

    PubMed

    Chen, Jiongjiong; Hu, Qun; Zhang, Yu; Lu, Chen; Kuang, Hanhui

    2014-01-01

    Miniature inverted-repeat transposable elements (MITEs) are prevalent in eukaryotic species including plants. MITE families vary dramatically and usually cannot be identified based on homology. In this study, we de novo identified MITEs from 41 plant species, using computer programs MITE Digger, MITE-Hunter and/or Repetitive Sequence with Precise Boundaries (RSPB). MITEs were found in all, but one (Cyanidioschyzon merolae), species. Combined with the MITEs identified previously from the rice genome, >2.3 million sequences from 3527 MITE families were obtained from 41 plant species. In general, higher plants contain more MITEs than lower plants, with a few exceptions such as papaya, with only 538 elements. The largest number of MITEs is found in apple, with 237 302 MITE sequences. The number of MITE sequences in a genome is significantly correlated with genome size. A series of databases (plant MITE databases, P-MITE), available online at http://pmite.hzau.edu.cn/django/mite/, was constructed to host all MITE sequences from the 41 plant genomes. The databases are available for sequence similarity searches (BLASTN), and MITE sequences can be downloaded by family or by genome. The databases can be used to study the origin and amplification of MITEs, MITE-derived small RNAs and roles of MITEs on gene and genome evolution. PMID:24174541

  8. The distribution of inverted repeat sequences in the Saccharomyces cerevisiae genome

    PubMed Central

    Benson, Gary; Gelfand, Yevgeniy; Benham, Craig J.

    2010-01-01

    Although a variety of possible functions have been proposed for inverted repeat sequences (IRs), it is not known which of them might occur in vivo. We investigate this question by assessing the distributions and properties of IRs in the Saccharomyces cerevisiae (SC) genome. Using the IRFinder algorithm we detect 100,514 IRs having copy length greater than 6 bp and spacer length less than 77 bp. To assess statistical significance we also determine the IR distributions in two types of randomization of the S. cerevisiae genome. We find that the S. cerevisiae genome is significantly enriched in IRs relative to random. The S. cerevisiae IRs are significantly longer and contain fewer imperfections than those from the randomized genomes, suggesting that processes to lengthen and/or correct errors in IRs may be operative in vivo. The S. cerevisiae IRs are highly clustered in intergenic regions, while their occurrence in coding sequences is consistent with random. Clustering is stronger in the 3′ flanks of genes than in their 5′ flanks. However, the S. cerevisiae genome is not enriched in those IRs that would extrude cruciforms, suggesting that this is not a common event. Various explanations for these results are considered. Electronic supplementary material The online version of this article (doi:10.1007/s00294-010-0302-6) contains supplementary material, which is available to authorized users. PMID:20446088

  9. The complete chloroplast genome of Ginkgo biloba reveals the mechanism of inverted repeat contraction.

    PubMed

    Lin, Ching-Ping; Wu, Chung-Shien; Huang, Ya-Yi; Chaw, Shu-Miaw

    2012-01-01

    We determined the complete chloroplast genome (cpDNA) of Ginkgo biloba (common name: ginkgo), the only relict of ginkgophytes from the Triassic Period. The cpDNA molecule of ginkgo is quadripartite and circular, with a length of 156,945 bp, which is 6,458 bp shorter than that of Cycas taitungensis. In ginkgo cpDNA, rpl23 becomes pseudo, only one copy of ycf2 is retained, and there are at least five editing sites. We propose that the retained ycf2 is a duplicate of the ancestral ycf2, and the ancestral one has been lost from the inverted repeat A (IR(A)). This loss event should have occurred and led to the contraction of IRs after ginkgos diverged from other gymnosperms. A novel cluster of three transfer RNA (tRNA) genes, trnY-AUA, trnC-ACA, and trnSeC-UCA, was predicted to be located between trnC-GCA and rpoB of the large single-copy region. Our phylogenetic analysis strongly suggests that the three predicted tRNA genes are duplicates of trnC-GCA. Interestingly, in ginkgo cpDNA, the loss of one ycf2 copy does not significantly elevate the synonymous rate (Ks) of the retained copy, which disagrees with the view of Perry and Wolfe (2002) that one of the two-copy genes is subjected to elevated Ks when its counterpart has been lost. We hypothesize that the loss of one ycf2 is likely recent, and therefore, the acquired Ks of the retained copy is low. Our data reveal that ginkgo possesses several unique features that contribute to our understanding of the cpDNA evolution in seed plants. PMID:22403032

  10. Cell culture-induced gradual and frequent epigenetic reprogramming of invertedly repeated tobacco transgene epialleles.

    PubMed

    Krizova, Katerina; Fojtova, Miloslava; Depicker, Ann; Kovarik, Ales

    2009-03-01

    Using a two-component transgene system involving two epiallelic variants of the invertedly repeated transgenes in locus 1 (Lo1) and a homologous single-copy transgene locus 2 (Lo2), we have studied the stability of the methylation patterns and trans-silencing interactions in cell culture and regenerated tobacco (Nicotiana tabacum) plants. The posttranscriptionally silenced (PTGS) epiallele of the Lo1 trans-silences and trans-methylates the target Lo2 in a hybrid (Lo1/Lo2 line), while its transcriptionally silenced variant (Lo1E) does not. This pattern was stable over several generations in plants. However, in early Lo1E/Lo2 callus, decreased transgene expression and partial loss of Lo1E promoter methylation compared with leaf tissue in the parental plant were observed. Analysis of small RNA species and coding region methylation suggested that the transgenes were silenced by a PTGS mechanism. The Lo1/Lo2 line remained silenced, but the nonmethylated Lo1 promoter acquired partial methylation in later callus stages. These data indicate that a cell culture process has brought both epialleles to a similar epigenetic ground. Bisulfite sequencing of the 35S promoter within the Lo1 silencer revealed molecules with no, intermediate, and high levels of methylation, demonstrating, to our knowledge for the first time, cell-to-cell methylation diversity of callus. Regenerated plants showed high interindividual but low intraindividual epigenetic variability, indicating that the callus-induced epiallelic variants were transmitted to plants and became fixed. We propose that epigenetic changes associated with dedifferentiation might influence regulatory pathways mediated by trans-PTGS processes. PMID:19129419

  11. Conserved Gene Order and Expanded Inverted Repeats Characterize Plastid Genomes of Thalassiosirales

    PubMed Central

    Ashworth, Matt P.; Baeshen, Nabih A.; Baeshen, Mohammad N.; Bahieldin, Ahmed; Theriot, Edward C.; Jansen, Robert K.

    2014-01-01

    Diatoms are mostly photosynthetic eukaryotes within the heterokont lineage. Variable plastid genome sizes and extensive genome rearrangements have been observed across the diatom phylogeny, but little is known about plastid genome evolution within order- or family-level clades. The Thalassiosirales is one of the more comprehensively studied orders in terms of both genetics and morphology. Seven complete diatom plastid genomes are reported here including four Thalassiosirales: Thalassiosira weissflogii, Roundia cardiophora, Cyclotella sp. WC03_2, Cyclotella sp. L04_2, and three additional non-Thalassiosirales species Chaetoceros simplex, Cerataulina daemon, and Rhizosolenia imbricata. The sizes of the seven genomes vary from 116,459 to 129,498 bp, and their genomes are compact and lack introns. The larger size of the plastid genomes of Thalassiosirales compared to other diatoms is due primarily to expansion of the inverted repeat. Gene content within Thalassiosirales is more conserved compared to other diatom lineages. Gene order within Thalassiosirales is highly conserved except for the extensive genome rearrangement in Thalassiosira oceanica. Cyclotella nana, Thalassiosira weissflogii and Roundia cardiophora share an identical gene order, which is inferred to be the ancestral order for the Thalassiosirales, differing from that of the other two Cyclotella species by a single inversion. The genes ilvB and ilvH are missing in all six diatom plastid genomes except for Cerataulina daemon, suggesting an independent gain of these genes in this species. The acpP1 gene is missing in all Thalassiosirales, suggesting that its loss may be a synapomorphy for the order and this gene may have been functionally transferred to the nucleus. Three genes involved in photosynthesis, psaE, psaI, psaM, are missing in Rhizosolenia imbricata, which represents the first documented instance of the loss of photosynthetic genes in diatom plastid genomes. PMID:25233465

  12. Evolutionary genomics of miniature inverted-repeat transposable elements (MITEs) in Brassica.

    PubMed

    Nouroz, Faisal; Noreen, Shumaila; Heslop-Harrison, J S

    2015-12-01

    Miniature inverted-repeat transposable elements (MITEs) are truncated derivatives of autonomous DNA transposons, and are dispersed abundantly in most eukaryotic genomes. We aimed to characterize various MITEs families in Brassica in terms of their presence, sequence characteristics and evolutionary activity. Dot plot analyses involving comparison of homoeologous bacterial artificial chromosome (BAC) sequences allowed identification of 15 novel families of mobile MITEs. Of which, 5 were Stowaway-like with TA Target Site Duplications (TSDs), 4 Tourist-like with TAA/TTA TSDs, 5 Mutator-like with 9-10 bp TSDs and 1 novel MITE (BoXMITE1) flanked by 3 bp TSDs. Our data suggested that there are about 30,000 MITE-related sequences in Brassica rapa and B. oleracea genomes. In situ hybridization showed one abundant family was dispersed in the A-genome, while another was located near 45S rDNA sites. PCR analysis using primers flanking sequences of MITE elements detected MITE insertion polymorphisms between and within the three Brassica (AA, BB, CC) genomes, with many insertions being specific to single genomes and others showing evidence of more recent evolutionary insertions. Our BAC sequence comparison strategy enables identification of evolutionarily active MITEs with no prior knowledge of MITE sequences. The details of MITE families reported in Brassica enable their identification, characterization and annotation. Insertion polymorphisms of MITEs and their transposition activity indicated important mechanism of genome evolution and diversification. MITE families derived from known Mariner, Harbinger and Mutator DNA transposons were discovered, as well as some novel structures. The identification of Brassica MITEs will have broad applications in Brassica genomics, breeding, hybridization and phylogeny through their use as DNA markers. PMID:26129767

  13. Turn-on of Inactive Genes by Promoter Recruitment in ESCHERICHIA COLI: Inverted Repeats Resulting in Artificial Divergent Operons

    PubMed Central

    Charlier, Daniel; Severne, Yvonne; Zafarullah, Muhamad; Glansdorff, Nicolas

    1983-01-01

    We have characterized two rearrangements consisting of inverted repeats of the argE gene. The promoters (p) of argE and of argCBH face each other over an internal operator. The rearrangements were obained as reactivations of argE in a strain harboring an argEp deletion on a λdarg prophage. In both cases the repeat included argE and argCBHp on either side of a unique sequence; the result is a divergent operon in which each copy of argCBHp reads into the adjacent argE repeat. In one case, the pair of repeats adjoins the silent parental gene, forming a triplication (← → ←). The other rearrangement consists of a single argE palindrome, but the whole prophage is rearranged into an inverted repeat, analogous to certain λdv's. Both structures could be explained by breakage of a replication fork passing argE and by inaccurate rejoining of strands. The λdv-like rearrangement would result from breakage at both replication forks of a phage or prophage replicating during transient release of immunity. The triplication would imply breaking of a chromosomal replication fork, formation of a cyclic intermediate by recombination between the daughter duplex molecules and reinsertion into the parental argE gene. Formation of a triplication by replication errors involving appropriate strand switchings and branch migrations can not be excluded however. PMID:6227522

  14. Identification of miniature inverted-repeat transposable elements (MITEs) and biogenesis of their siRNAs in the Solanaceae: New functional implications for MITEs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Small RNAs regulate the genome by guiding transcriptional and post-transcriptional silencing machinery to specific target sequences, including genes and transposable elements (TEs). Although miniature inverted-repeat transposable elements (MITEs) are closely associated with euchromatic genes, the br...

  15. Validation and genotyping of multiple human polymorphic inversions mediated by inverted repeats reveals a high degree of recurrence.

    PubMed

    Aguado, Cristina; Gayà-Vidal, Magdalena; Villatoro, Sergi; Oliva, Meritxell; Izquierdo, David; Giner-Delgado, Carla; Montalvo, Víctor; García-González, Judit; Martínez-Fundichely, Alexander; Capilla, Laia; Ruiz-Herrera, Aurora; Estivill, Xavier; Puig, Marta; Cáceres, Mario

    2014-03-01

    In recent years different types of structural variants (SVs) have been discovered in the human genome and their functional impact has become increasingly clear. Inversions, however, are poorly characterized and more difficult to study, especially those mediated by inverted repeats or segmental duplications. Here, we describe the results of a simple and fast inverse PCR (iPCR) protocol for high-throughput genotyping of a wide variety of inversions using a small amount of DNA. In particular, we analyzed 22 inversions predicted in humans ranging from 5.1 kb to 226 kb and mediated by inverted repeat sequences of 1.6-24 kb. First, we validated 17 of the 22 inversions in a panel of nine HapMap individuals from different populations, and we genotyped them in 68 additional individuals of European origin, with correct genetic transmission in ∼ 12 mother-father-child trios. Global inversion minor allele frequency varied between 1% and 49% and inversion genotypes were consistent with Hardy-Weinberg equilibrium. By analyzing the nucleotide variation and the haplotypes in these regions, we found that only four inversions have linked tag-SNPs and that in many cases there are multiple shared SNPs between standard and inverted chromosomes, suggesting an unexpected high degree of inversion recurrence during human evolution. iPCR was also used to check 16 of these inversions in four chimpanzees and two gorillas, and 10 showed both orientations either within or between species, providing additional support for their multiple origin. Finally, we have identified several inversions that include genes in the inverted or breakpoint regions, and at least one disrupts a potential coding gene. Thus, these results represent a significant advance in our understanding of inversion polymorphism in human populations and challenge the common view of a single origin of inversions, with important implications for inversion analysis in SNP-based studies. PMID:24651690

  16. Validation and Genotyping of Multiple Human Polymorphic Inversions Mediated by Inverted Repeats Reveals a High Degree of Recurrence

    PubMed Central

    Aguado, Cristina; Gayà-Vidal, Magdalena; Villatoro, Sergi; Oliva, Meritxell; Izquierdo, David; Giner-Delgado, Carla; Montalvo, Víctor; García-González, Judit; Martínez-Fundichely, Alexander; Capilla, Laia; Ruiz-Herrera, Aurora; Estivill, Xavier; Puig, Marta; Cáceres, Mario

    2014-01-01

    In recent years different types of structural variants (SVs) have been discovered in the human genome and their functional impact has become increasingly clear. Inversions, however, are poorly characterized and more difficult to study, especially those mediated by inverted repeats or segmental duplications. Here, we describe the results of a simple and fast inverse PCR (iPCR) protocol for high-throughput genotyping of a wide variety of inversions using a small amount of DNA. In particular, we analyzed 22 inversions predicted in humans ranging from 5.1 kb to 226 kb and mediated by inverted repeat sequences of 1.6–24 kb. First, we validated 17 of the 22 inversions in a panel of nine HapMap individuals from different populations, and we genotyped them in 68 additional individuals of European origin, with correct genetic transmission in ∼12 mother-father-child trios. Global inversion minor allele frequency varied between 1% and 49% and inversion genotypes were consistent with Hardy-Weinberg equilibrium. By analyzing the nucleotide variation and the haplotypes in these regions, we found that only four inversions have linked tag-SNPs and that in many cases there are multiple shared SNPs between standard and inverted chromosomes, suggesting an unexpected high degree of inversion recurrence during human evolution. iPCR was also used to check 16 of these inversions in four chimpanzees and two gorillas, and 10 showed both orientations either within or between species, providing additional support for their multiple origin. Finally, we have identified several inversions that include genes in the inverted or breakpoint regions, and at least one disrupts a potential coding gene. Thus, these results represent a significant advance in our understanding of inversion polymorphism in human populations and challenge the common view of a single origin of inversions, with important implications for inversion analysis in SNP-based studies. PMID:24651690

  17. Correlations between long inverted repeat (LIR) features, deletion size and distance from breakpoint in human gross gene deletions

    PubMed Central

    Aygun, Nevim

    2015-01-01

    Long inverted repeats (LIRs) have been shown to induce genomic deletions in yeast. In this study, LIRs were investigated within ±10 kb spanning each breakpoint from 109 human gross deletions, using Inverted Repeat Finder (IRF) software. LIR number was significantly higher at the breakpoint regions, than in control segments (P < 0.001). In addition, it was found that strong correlation between 5′ and 3′ LIR numbers, suggesting contribution to DNA sequence evolution (r = 0.85, P < 0.001). 138 LIR features at ±3 kb breakpoints in 89 (81%) of 109 gross deletions were evaluated. Significant correlations were found between distance from breakpoint and loop length (r = −0.18, P < 0.05) and stem length (r = −0.18, P < 0.05), suggesting DNA strands are potentially broken in locations closer to bigger LIRs. In addition, bigger loops cause larger deletions (r = 0.19, P < 0.05). Moreover, loop length (r = 0.29, P < 0.02) and identity between stem copies (r = 0.30, P < 0.05) of 3′ LIRs were more important in larger deletions. Consequently, DNA breaks may form via LIR-induced cruciform structure during replication. DNA ends may be later repaired by non-homologous end-joining (NHEJ), with following deletion. PMID:25657065

  18. MUST: a system for identification of miniature inverted-repeat transposable elements and applications to Anabaena variabilis and Haloquadratum walsbyi.

    PubMed

    Chen, Yong; Zhou, Fengfeng; Li, Guojun; Xu, Ying

    2009-05-01

    Transposable elements (TE) are functionally important genetic elements that can move within a genome. Miniature inverted-repeat transposable elements (MITEs) constitute a class of transposable elements that are usually small in size and have high numbers of conserved copies. Identifying all the MITEs in a genome could provide new insights about gene evolution and genome dynamics of the organism. We present a web-based MITE Uncovering SysTem (MUST) for prediction and analyses of MITEs at a genome level. MUST reliably found both the previously known and novel MITEs in the two bacterial genomes, Anabaena variabilis ATCC 29413 and Haloquadratum walsbyi DSM 16790. MUST is available at http://csbl1.bmb.uga.edu/ffzhou/MUST/ (the standalone version is available upon request). Supplementary data associated with this article are available in the online version or at: http://csbl1.bmb.uga.edu/ffzhou/MUST/supp/. PMID:19393167

  19. A MATLAB-based tool for accurate detection of perfect overlapping and nested inverted repeats in DNA sequences

    PubMed Central

    Sreeskandarajan, Sutharzan; Flowers, Michelle M.; Karro, John E.; Liang, Chun

    2014-01-01

    Summary: Palindromic sequences, or inverted repeats (IRs), in DNA sequences involve important biological processes such as DNA–protein binding, DNA replication and DNA transposition. Development of bioinformatics tools that are capable of accurately detecting perfect IRs can enable genome-wide studies of IR patterns in both prokaryotes and eukaryotes. Different from conventional string-comparison approaches, we propose a novel algorithm that uses a cumulative score system based on a prime number representation of nucleotide bases. We then implemented this algorithm as a MATLAB-based program for perfect IR detection. In comparison with other existing tools, our program demonstrates a high accuracy in detecting nested and overlapping IRs. Availability and implementation: The source code is freely available on (http://bioinfolab.miamioh.edu/bioinfolab/palindrome.php) Contact: liangc@miamioh.edu or karroje@miamioh.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:24215021

  20. Evolution of short inverted repeat in cupressophytes, transfer of accD to nucleus in Sciadopitys verticillata and phylogenetic position of Sciadopityaceae

    PubMed Central

    Li, Jia; Gao, Lei; Chen, Shanshan; Tao, Ke; Su, Yingjuan; Wang, Ting

    2016-01-01

    Sciadopitys verticillata is an evergreen conifer and an economically valuable tree used in construction, which is the only member of the family Sciadopityaceae. Acquisition of the S. verticillata chloroplast (cp) genome will be useful for understanding the evolutionary mechanism of conifers and phylogenetic relationships among gymnosperm. In this study, we have first reported the complete chloroplast genome of S. verticillata. The total genome is 138,284 bp in length, consisting of 118 unique genes. The S. verticillata cp genome has lost one copy of the canonical inverted repeats and shown distinctive genomic structure comparing with other cupressophytes. Fifty-three simple sequence repeat loci and 18 forward tandem repeats were identified in the S. verticillata cp genome. According to the rearrangement of cupressophyte cp genome, we proposed one mechanism for the formation of inverted repeat: tandem repeat occured first, then rearrangement divided the tandem repeat into inverted repeats located at different regions. Phylogenetic estimates inferred from 59-gene sequences and cpDNA organizations have both shown that S. verticillata was sister to the clade consisting of Cupressaceae, Taxaceae, and Cephalotaxaceae. Moreover, accD gene was found to be lost in the S. verticillata cp genome, and a nucleus copy was identified from two transcriptome data. PMID:26865528

  1. The Complex Genetic Context of blaPER-1 Flanked by Miniature Inverted-Repeat Transposable Elements in Acinetobacter johnsonii

    PubMed Central

    Zong, Zhiyong

    2014-01-01

    On a large plasmid of Acinetobacter johnsonii strain XBB1 from hospital sewage, blaPER-1 and ISCR1 were found in a complex Tn402-like integron carrying an arr3-aacA4 cassette array. The integron was truncated by the same 439-bp miniature inverted-repeat transposable element (MITE) at both ends. blaPER-1 and its complex surroundings might have been mobilized by the MITEst into an orf of unknown function, evidenced by the presence of the characteristic 5-bp direct target repeats. The same 439-bp MITEs have also been found flanking class 1 integrons carrying metallo-β-lactamases genes blaIMP-1, blaIMP-5 and blaVIM-2 before but without ISCR1. Although the cassette arrays are different, integrons have always been truncated by the 439-bp MITEs at the exact same locations. The results suggested that MITEs might be able to mobilize class 1 integrons via transposition or homologous recombination and therefore represent a possible common mechanism for mobilizing antimicrobial resistance determinants. PMID:24587208

  2. An Annotated Catalog of Inverted Repeats of Caenorhabditis elegans Chromosomes III and X, with Observations Concerning Odd/Even Biases and Conserved Motifs

    PubMed Central

    LeBlanc, Mark D.; Aspeslagh, Glen; Buggia, Nathan P.; Dyer, Betsey D.

    2000-01-01

    We have taken a computational approach to the problem of discovering and deciphering the grammar and syntax of gene regulation in eukaryotes. A logical first step is to produce an annotated catalog of all regulatory sites in a given genome. Likely candidates for such sites are direct and indirect repeats, including three subcategories of indirect repeats: inverted (palindromic), everted, and mirror-image repeats. To that end we have produced a searchable database of inverted repeats of chromosomes III and X of Caenorhabditis elegans, the first completely sequenced multicellular eukaryote. Initial results from the use of this catalog are observations concerning odd/even biases in perfect IRs. The potential usefulness of the catalog as a discovery tool for promoters was shown for some of the genes involved with G-protein functions and for heat shock protein 104 (hsp104). PMID:10984456

  3. Insertion of miniature subterminal inverted repeat-like elements in diapause-regulated genes in the Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Determining the genomic structure of diapause-associated transcripts (DAT) -2 and -3 led to the isolation of four novel miniature subterminal inverted repeat-like elements (MSITE): Mild-1, -2, -3 and -4. Mild-1a is inserted within the first intron of diapause protein-1. Mild-1a is 284 bp in length, ...

  4. Single inverted terminal repeats of the Junonia coenia Densovirus promotes somatic chromosomal integration of vector plasmids in insect cells and supports high efficiency expression

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plasmids that contain a disrupted genome of the Junonia coenia densovirus (JcDNV) integrate into the chromosomes of the somatic cells of insects. When subcloned individually, both the P9 inverted terminal repeat (P9-ITR) and the P93-ITR promote the chromosomal integration of vector plasmids in insec...

  5. Mobility and Generation of Mosaic Non-Autonomous Transposons by Tn3-Derived Inverted-Repeat Miniature Elements (TIMEs)

    PubMed Central

    Szuplewska, Magdalena; Ludwiczak, Marta; Lyzwa, Katarzyna; Czarnecki, Jakub; Bartosik, Dariusz

    2014-01-01

    Functional transposable elements (TEs) of several Pseudomonas spp. strains isolated from black shale ore of Lubin mine and from post-flotation tailings of Zelazny Most in Poland, were identified using a positive selection trap plasmid strategy. This approach led to the capture and characterization of (i) 13 insertion sequences from 5 IS families (IS3, IS5, ISL3, IS30 and IS1380), (ii) isoforms of two Tn3-family transposons – Tn5563a and Tn4662a (the latter contains a toxin-antitoxin system), as well as (iii) non-autonomous TEs of diverse structure, ranging in size from 262 to 3892 bp. The non-autonomous elements transposed into AT-rich DNA regions and generated 5- or 6-bp sequence duplications at the target site of transposition. Although these TEs lack a transposase gene, they contain homologous 38-bp-long terminal inverted repeat sequences (IRs), highly conserved in Tn5563a and many other Tn3-family transposons. The simplest elements of this type, designated TIMEs (Tn3 family-derived Inverted-repeat Miniature Elements) (262 bp), were identified within two natural plasmids (pZM1P1 and pLM8P2) of Pseudomonas spp. It was demonstrated that TIMEs are able to mobilize segments of plasmid DNA for transposition, which results in the generation of more complex non-autonomous elements, resembling IS-driven composite transposons in structure. Such transposon-like elements may contain different functional genetic modules in their core regions, including plasmid replication systems. Another non-autonomous element “captured” with a trap plasmid was a TIME derivative containing a predicted resolvase gene and a res site typical for many Tn3-family transposons. The identification of a portable site-specific recombination system is another intriguing example confirming the important role of non-autonomous TEs of the TIME family in shuffling genetic information in bacterial genomes. Transposition of such mosaic elements may have a significant impact on diversity and evolution

  6. Terminal Bacteroid Differentiation Is Associated With Variable Morphological Changes in Legume Species Belonging to the Inverted Repeat-Lacking Clade.

    PubMed

    Montiel, Jesús; Szűcs, Attila; Boboescu, Iulian Z; Gherman, Vasile D; Kondorosi, Éva; Kereszt, Attila

    2016-03-01

    Medicago and closely related legume species from the inverted repeat-lacking clade (IRLC) impose terminal differentiation onto their bacterial endosymbionts, manifested in genome endoreduplication, cell enlargement, and loss of cell-division capacity. Nodule-specific cysteine-rich (NCR) secreted host peptides are plant effectors of this process. As bacteroids in other IRLC legumes, such as Cicer arietinum and Glycyrrhiza lepidota, were reported not to display features of terminal differentiation, we investigated the fate of bacteroids in species from these genera as well as in four other species representing distinct genera of the phylogenetic tree for this clade. Bacteroids in all tested legumes proved to be larger in size and DNA content than cultured cells; however, the degree of cell elongation was rather variable in the different species. In addition, the reproductive ability of the bacteroids isolated from these legumes was remarkably reduced. In all IRLC species with available sequence data, the existence of NCR genes was found. These results indicate that IRLC legumes provoke terminal differentiation of their endosymbionts with different morphotypes, probably with the help of NCR peptides. PMID:26713350

  7. The Origin and Evolution of Six Miniature Inverted-Repeat Transposable Elements in Bombyx mori and Rhodnius prolixus

    PubMed Central

    Zhang, Hua-Hao; Xu, Hong-En; Shen, Yi-Hong; Han, Min-Jin; Zhang, Ze

    2013-01-01

    Miniature inverted-repeat transposable elements (MITEs) are a specific group of nonautonomous DNA transposons, and they are distributed in a wide range of hosts. However, the origin and evolutionary history of MITEs in eukaryotic genomes remain unclear. In this study, six MITEs were identified in the silkworm (Bombyx mori). Five elements are grouped into four known superfamilies of DNA transposons, and one represents a novel class of MITEs. Unexpectedly, six similar MITEs are also present in the triatomine bug (Rhodnius prolixus) that diverged from the common ancestor with the silkworm about 370 Ma. However, they show different lengths in two species, suggesting that they are different derivatives of progenitor transposons. Three direct progenitor transposons (Sola1, hobo/Ac/Tam [hAT], and Ginger2) are also identified in some other organisms, and several lines of evidence suggested that these autonomous elements might have been independently and horizontally transferred into their hosts. Furthermore, it is speculated that the twisted-wing parasites may be the candidate vectors for these horizontal transfers. The data presented in this study provide some new insights into the origin and evolutionary history of MITEs in the silkworm and triatomine bug. PMID:24115603

  8. Evolutionary dynamics of the plastid inverted repeat: the effects of expansion, contraction, and loss on substitution rates.

    PubMed

    Zhu, Andan; Guo, Wenhu; Gupta, Sakshi; Fan, Weishu; Mower, Jeffrey P

    2016-03-01

    Rates of nucleotide substitution were previously shown to be several times slower in the plastid inverted repeat (IR) compared with single-copy (SC) regions, suggesting that the IR provides enhanced copy-correction activity. To examine the generality of this synonymous rate dependence on the IR, we compared plastomes from 69 pairs of closely related species representing 52 families of angiosperms, gymnosperms, and ferns. We explored the breadth of IR boundary shifts in land plants and demonstrate that synonymous substitution rates are, on average, 3.7 times slower in IR genes than in SC genes. In addition, genes moved from the SC into the IR exhibit lower synonymous rates consistent with other IR genes, while genes moved from the IR into the SC exhibit higher rates consistent with other SC genes. Surprisingly, however, several plastid genes from Pelargonium, Plantago, and Silene have highly accelerated synonymous rates despite their IR localization. Together, these results provide strong evidence that the duplicative nature of the IR reduces the substitution rate within this region. The anomalously fast-evolving genes in Pelargonium, Plantago, and Silene indicate localized hypermutation, potentially induced by a higher level of error-prone double-strand break repair in these regions, which generates substitutional rate variation. PMID:26574731

  9. Efficient transposition of the youngest miniature inverted repeat transposable element family of yellow fever mosquito in yeast.

    PubMed

    Fattash, Isam; Lee, Chia-Ni; Mo, Kaiguo; Yang, Guojun

    2015-05-01

    Miniature inverted repeat transposable elements (MITEs) are often the most numerous DNA transposons in plant and animal genomes. The dramatic amplification of MITE families during evolution is puzzling, because the transposase sources for the vast majority of MITE families are unknown. The yellow fever mosquito genome contains > 220-Mb MITE sequences; however, transposition activity has not been demonstrated for any of the MITE families. The Gnome elements are the youngest MITE family in this genome, with at least 116 identical copies. To test whether the putative autonomous element Ozma is capable of mobilizing Gnome and its two sibling MITEs, analyses were performed in a yeast transposition assay system. Whereas the wild-type transposase resulted in very low transposition activity, mutations in the region containing a putative nuclear export signal motif resulted in a dramatic (at least 4160-fold) increase in transposition frequency. We have also demonstrated that each residue of the novel DD37E motif is required for the activity of the Ozma transposase. Footprint sequences left at the donor sites suggest that the transposase may cleave between the second and the third nucleotides from the 5' ends of the elements. The excised elements reinsert specifically at dinucleotide 'TA', ~ 55% of them in yeast genes. The elements described in this article could potentially be useful as genetic tools for genetic manipulation of mosquitoes. PMID:25754725

  10. Construction of effective inverted repeat silencing constructs using sodium bisulfite treatment coupled with strand-specific PCR.

    PubMed

    Taylor, Sarah H; Harmse, Johan; Arbuthnot, Patrick; Van Den Berg, Fiona; Weinberg, Marco S; Rey, Marie E C

    2012-04-01

    RNA silencing has been exploited to produce transgenic plants with resistance to viral pathogens via posttranscriptional gene silencing (PTGS). In some cases, this technology is difficult to apply due to the instability of inverted repeat (IR) constructs during cloning and plant transformation. Although such constructs have been shown to be stabilized with introns and efficiently induce RNA silencing, we found that the Pdk intron did not stabilize South African cassava mosaic virus (SACMV) silencing constructs. Therefore, we developed a method for producing long SACMV IR constructs through bisulfite-induced base pair mismatches on the sense arm prior to IR assembly. Expression of SACMV BC1 mismatched IR constructs in the model test plant Nicotiana benthamiana resulted in a reduction in viral BC1 transcript levels, hence viral replication, upon SACMV infection. Mismatched SACMV AC1 IR constructs induced PTGS more efficiently in a N. benthamiana callus system than nonmismatched IR constructs. Our novel method for IR construct generation should be applicable to many sequences where the generation of these constructs has proven difficult in the past. PMID:22482441

  11. Deletion of a 77-Base-Pair Inverted Repeat Element Alters the Synthesis of Surface Polysaccharides in Porphyromonas gingivalis

    PubMed Central

    Bainbridge, Brian W.; Hirano, Takanori; Grieshaber, Nicole

    2015-01-01

    ABSTRACT Bacterial cell surface glycans, such as capsular polysaccharides and lipopolysaccharides (LPS), influence host recognition and are considered key virulence determinants. The periodontal pathogen Porphyromonas gingivalis is known to display at least three different types of surface glycans: O-LPS, A-LPS, and K-antigen capsule. We have shown that PG0121 (in strain W83) encodes a DNABII histone-like protein and that this gene is transcriptionally linked to the K-antigen capsule synthesis genes, generating a large ∼19.4-kb transcript (PG0104-PG0121). Furthermore, production of capsule is deficient in a PG0121 mutant strain. In this study, we report on the identification of an antisense RNA (asRNA) molecule located within a 77-bp inverted repeat (77bpIR) element located near the 5′ end of the locus. We show that overexpression of this asRNA decreases the amount of capsule produced, indicating that this asRNA can impact capsule synthesis in trans. We also demonstrate that deletion of the 77bpIR element and thereby synthesis of the large 19.4-kb transcript also diminishes, but does not eliminate, capsule synthesis. Surprisingly, LPS structures were also altered by deletion of the 77bpIR element, and reactivity to monoclonal antibodies specific to both O-LPS and A-LPS was eliminated. Additionally, reduced reactivity to these antibodies was also observed in a PG0106 mutant, indicating that this putative glycosyltransferase, which is required for capsule synthesis, is also involved in LPS synthesis in strain W83. We discuss our finding in the context of how DNABII proteins, an antisense RNA molecule, and the 77bpIR element may modulate expression of surface polysaccharides in P. gingivalis. IMPORTANCE The periodontal pathogen Porphyromonas gingivalis displays at least three different types of cell surface glycans: O-LPS, A-LPS, and K-antigen capsule. We have shown using Northern analysis that the K-antigen capsule locus encodes a large transcript (∼19.4 kb

  12. Genome-Wide Comparative Analysis of 20 Miniature Inverted-Repeat Transposable Element Families in Brassica rapa and B. oleracea

    PubMed Central

    Sampath, Perumal; Murukarthick, Jayakodi; Izzah, Nur Kholilatul; Lee, Jonghoon; Choi, Hong-Il; Shirasawa, Kenta; Choi, Beom-Soon; Liu, Shengyi; Nou, Ill-Sup; Yang, Tae-Jin

    2014-01-01

    Miniature inverted-repeat transposable elements (MITEs) are ubiquitous, non-autonomous class II transposable elements. Here, we conducted genome-wide comparative analysis of 20 MITE families in B. rapa, B. oleracea, and Arabidopsis thaliana. A total of 5894 and 6026 MITE members belonging to the 20 families were found in the whole genome pseudo-chromosome sequences of B. rapa and B. oleracea, respectively. Meanwhile, only four of the 20 families, comprising 573 members, were identified in the Arabidopsis genome, indicating that most of the families were activated in the Brassica genus after divergence from Arabidopsis. Copy numbers varied from 4 to 1459 for each MITE family, and there was up to 6-fold variation between B. rapa and B. oleracea. In particular, analysis of intact members showed that whereas eleven families were present in similar copy numbers in B. rapa and B. oleracea, nine families showed copy number variation ranging from 2- to 16-fold. Four of those families (BraSto-3, BraTo-3, 4, 5) were more abundant in B. rapa, and the other five (BraSto-1, BraSto-4, BraTo-1, 7 and BraHAT-1) were more abundant in B. oleracea. Overall, 54% and 51% of the MITEs resided in or within 2 kb of a gene in the B. rapa and B. oleracea genomes, respectively. Notably, 92 MITEs were found within the CDS of annotated genes, suggesting that MITEs might play roles in diversification of genes in the recently triplicated Brassica genome. MITE insertion polymorphism (MIP) analysis of 289 MITE members showed that 52% and 23% were polymorphic at the inter- and intra-species levels, respectively, indicating that there has been recent MITE activity in the Brassica genome. These recently activated MITE families with abundant MIP will provide useful resources for molecular breeding and identification of novel functional genes arising from MITE insertion. PMID:24747717

  13. Genome-wide comparative analysis of 20 miniature inverted-repeat transposable element families in Brassica rapa and B. oleracea.

    PubMed

    Sampath, Perumal; Murukarthick, Jayakodi; Izzah, Nur Kholilatul; Lee, Jonghoon; Choi, Hong-Il; Shirasawa, Kenta; Choi, Beom-Soon; Liu, Shengyi; Nou, Ill-Sup; Yang, Tae-Jin

    2014-01-01

    Miniature inverted-repeat transposable elements (MITEs) are ubiquitous, non-autonomous class II transposable elements. Here, we conducted genome-wide comparative analysis of 20 MITE families in B. rapa, B. oleracea, and Arabidopsis thaliana. A total of 5894 and 6026 MITE members belonging to the 20 families were found in the whole genome pseudo-chromosome sequences of B. rapa and B. oleracea, respectively. Meanwhile, only four of the 20 families, comprising 573 members, were identified in the Arabidopsis genome, indicating that most of the families were activated in the Brassica genus after divergence from Arabidopsis. Copy numbers varied from 4 to 1459 for each MITE family, and there was up to 6-fold variation between B. rapa and B. oleracea. In particular, analysis of intact members showed that whereas eleven families were present in similar copy numbers in B. rapa and B. oleracea, nine families showed copy number variation ranging from 2- to 16-fold. Four of those families (BraSto-3, BraTo-3, 4, 5) were more abundant in B. rapa, and the other five (BraSto-1, BraSto-4, BraTo-1, 7 and BraHAT-1) were more abundant in B. oleracea. Overall, 54% and 51% of the MITEs resided in or within 2 kb of a gene in the B. rapa and B. oleracea genomes, respectively. Notably, 92 MITEs were found within the CDS of annotated genes, suggesting that MITEs might play roles in diversification of genes in the recently triplicated Brassica genome. MITE insertion polymorphism (MIP) analysis of 289 MITE members showed that 52% and 23% were polymorphic at the inter- and intra-species levels, respectively, indicating that there has been recent MITE activity in the Brassica genome. These recently activated MITE families with abundant MIP will provide useful resources for molecular breeding and identification of novel functional genes arising from MITE insertion. PMID:24747717

  14. Identification and purification of a Drosophila protein that binds to the terminal 31-base-pair inverted repeats of the P transposable element

    SciTech Connect

    Rio, D.C.; Rubin, G.M.

    1988-12-01

    We have used DNase I footprinting and partially fractionated nuclear extracts from Drosophila Kc tissue culture cells to identify DNA-binding proteins that interact with the terminal repeats of P transposable elements. We have identified a binding activity that interacts specifically with a region of the 31-base-pair terminal inverted repeats that is directly adjacent to the duplication of target site DNA. Binding occurs to both the 5' and 3' inverted terminal repeats irrespective of the sequence of the duplicated target DNA. UV photochemical crosslinking studies suggest that the binding activity resides in a polypeptide of 65-70 kDa. Biochemical fractionation and oligonucleotide affinity chromatography have been used to purify the binding activity to near homogeneity and identify a polypeptide of 66 kDa in the highly purified preparations. The site to which binding occurs is included in a region absolutely required for P element transposition, suggesting that this binding protein may be a cellular factor involved in P element transposition.

  15. Association of an HLA-G 14-bp Insertion/Deletion polymorphism with high HBV replication in chronic hepatitis.

    PubMed

    Laaribi, A B; Zidi, I; Hannachi, N; Ben Yahia, H; Chaouch, H; Bortolotti, D; Zidi, N; Letaief, A; Yacoub, S; Boudabous, A; Rizzo, R; Boukadida, J

    2015-10-01

    Identification of an HLA-G 14-bp Insertion/Deletion (Ins/Del) polymorphism at the 3' untranslated region of HLA-G revealed its importance in HLA-G mRNA stability and HLA-G protein level variation. We evaluated the association between the HLA-G 14-bp Ins/Del polymorphism in patients with chronic Hepatitis B virus (HBV) infection in a case-control study. Genomic DNA was extracted from 263 patients with chronic HBV hepatitis and 246 control subjects and was examined for the HLA-G 14-bp Ins/Del polymorphism by PCR. The polymorphic variants were genotyped in chronic HBV seropositive cases stratified according to HBV DNA levels, fibrosis stages and in a control population. There was no statistical significant association between the 14-bp Ins/Del polymorphism and increased susceptibility to HBV infection neither for alleles (P = 0.09) nor for genotypes (P = 0.18). The stratification of HBV patients based on HBV DNA levels revealed an association between the 14-bp Ins/Del polymorphism and an enhanced HBV activity with high HBV DNA levels. In particular, the Ins allele was significantly associated with high HBV DNA levels (P = 0.0024, OR = 1.71, 95% CI 1.2-2.4). The genotype Ins/Ins was associated with a 2.5-fold (95% CI, 1.29-4.88) increased risk of susceptibility to high HBV replication compared with the Del/Del and Ins/Del genotypes. This susceptibility is linked to the presence of two Ins alleles. No association was observed between the 14-bp Ins/Del polymorphism and fibrosis stage of HBV infection. We observed an association between the 14-bp Ins/Del polymorphism and high HBV replication characterized by high HBV DNA levels in chronic HBV patients. These results suggest a potential prognostic value for disease outcome evaluation. PMID:25619305

  16. Construction and gene expression analysis of a single-stranded DNA minivector based on an inverted terminal repeat of adeno-associated virus.

    PubMed

    Ping, Han; Liu, Xiaomei; Zhu, Dongqin; Li, Taiming; Zhang, Chun

    2015-04-01

    The plasmid vectors currently used for nonviral gene transfer have the disadvantage of carrying a bacterial backbone and an antibiotic resistance gene, which may cause side effects. The adeno-associated virus (AAV) genome is a linear single-stranded DNA (ssDNA) molecule with palindromic inverted terminal repeat (ITR) sequences forming double-stranded DNA (dsDNA) hairpin (HP) structures at each end. Based on the AAV genome, we constructed an AAV-ITR ssDNA minivector that consists of a GFP expression cassette flanked by both ITR sequences of 125 nucleotides. The minivectors were produced by digestion of the parental plasmids followed by denaturation. The self-complementary inverted T-shaped HP structure of the minivector was automatically formed. The HEK 293T cells were transfected with the AAV-ITR ssDNA minivector, plasmid, and dsDNA expression cassette. The results showed that AAV-ITR ssDNA minivector had relatively low gene expression efficiency in vitro. However, we found that the GFP expression efficiency of the D sequence-deleted AAV-ITR ssDNA minivector was significantly increased and was similar to those obtained with the plasmid and dsDNA expression cassette. Our data suggest that the AAV-ITR ssDNA minivector may be a new type of gene expression vector for gene therapy besides the virus and plasmid. PMID:25555376

  17. Analysis of the genome sequence of the pathogenic Muscovy duck parvovirus strain YY reveals a 14-nucleotide-pair deletion in the inverted terminal repeats.

    PubMed

    Wang, Jianye; Huang, Yu; Zhou, Mingxu; Zhu, Guoqiang

    2016-09-01

    Genomic information about Muscovy duck parvovirus is still limited. In this study, the genome of the pathogenic MDPV strain YY was sequenced. The full-length genome of YY is 5075 nucleotides (nt) long, 57 nt shorter than that of strain FM. Sequence alignment indicates that the 5' and 3' inverted terminal repeats (ITR) of strain YY contain a 14-nucleotide-pair deletion in the stem of the palindromic hairpin structure in comparison to strain FM and FZ91-30. The deleted region contains one "E-box" site and one repeated motif with the sequence "TTCCGGT" or "ACCGGAA". Phylogenetic trees constructed based the protein coding genes concordantly showed that YY, together with nine other MDPV isolates from various places, clustered in a separate branch, distinct from the branch formed by goose parvovirus (GPV) strains. These results demonstrate that, despite the distinctive deletion, the YY strain still belongs to the classical MDPV group. Moreover, the deletion of ITR may contribute to the genome evolution of MDPV under immunization pressure. PMID:27344160

  18. An investigation into the association between HLA-G 14 bp insertion/deletion polymorphism and multiple sclerosis susceptibility.

    PubMed

    Mohammadi, Nabiallah; Adib, Minoo; Alsahebfosoul, Fereshteh; Kazemi, Mohammad; Etemadifar, Masoud

    2016-01-15

    Human Leukocyte Antigen G (HLA-G) gene polymorphism and expression rate have recently been suggested to have a potential role in susceptibility to Multiple Sclerosis (MS), a chronic inflammatory demyelinating and neurodegenerative disease of the central nervous system with unknown etiology. The aim of this study was to investigate the association of the frequency of HLA-G gene 14 bp insertion/deletion polymorphism and its plasma level with MS susceptibility. In this study, the HLA-G gene from 212 patients and 210 healthy individuals was amplified using real time PCR and screened for the 14 bp insertion/deletion polymorphism. In addition, HLA-G plasma levels of the patients were measured and compared to normal controls by ELISA method. Our results revealed that 14 bp insertion in HLA-G could result in lower plasma HLA-G level of the subjects, regardless of their health status and vice versa. Additionally, significant correlation of HLA-G genotype and its plasma level with MS susceptibility was observed. In conclusion, not only HLA-G 14 bp insertion/deletion polymorphism could be associated with expression rate of the HLA-G gene and its plasma level, but also could be considered as a risk factor for susceptibility to MS in our study population. PMID:26711580

  19. Role of 14-Bp HLA-G, INDEL Polymorphism in Recurrent Miscarriage.

    PubMed

    Afkhami, Fateme; Yazdani, Neda; Khaniani, Mahmoud Shekari; Derakhshan, Sima Mansoori

    2016-01-01

    Mothers and their fetuses are hereditarily unlike. Surprisingly, no less than 50% human pregnancies reach full term despite the tendency of the immune system to eliminate of non-self units. Reduction of adaptive maternal immune answer, which is planned to reject strange factors, is essential for a pregnancy to reach full term. However, approximately 5% couples trying to conceive experience 2 recurrent miscarriages (RMs).HLA-G, which is produced by the external trophectoderm layer and has unique biological features, is involved in the implantation and maintenance of fetus. Serum HLA-G levels are correlated with the risk of RM. Recent studies indicate that a 14-bp HLA-G, INDEL polymorphism decreases the level of HLA-G mRNA, which in turn decreases the amount of HLA-G produced. An understanding of gene parameter and the function of polymorphic sites in the functioning of HLA-G products may enable the development of approaches targeting HLA-G for more detail of causes of RM. PMID:27357874

  20. Association between sHLA-G and HLA-G 14-bp deletion/insertion polymorphism in Crohn's disease.

    PubMed

    Zidi, Inès; Ben Yahia, Hamza; Bortolotti, Daria; Mouelhi, Leila; Laaribi, Ahmed Baligh; Ayadi, Shema; Zidi, Nour; Houissa, Fatma; Debbech, Radhouane; Boudabous, Abdellatif; Najjar, Taoufik; Di Luca, Dario; Rizzo, Roberta

    2015-06-01

    The aim of this study was to evaluate the association between the HLA-G 14-bp deletion/insertion (Del/Ins) polymorphism and soluble (s) HLA-G production in patients with Crohn's disease (CD). We analyzed also the sHLA-G molecules by ELISA and western blot in plasma samples. Among unselected patients, the 14-bp Del/Ins polymorphism was not significantly associated with increased CD risk neither for alleles (P = 0.371) nor for genotypes (P = 0.625). However, a significant association was reported between the 14-bp Del/Ins polymorphism and CD, in particular in young-onset CD patients for alleles [P = 0.020, odds ratio (OR) = 2.438, 95% confidence interval (CI): 1.13-5.25] but not with adult-onset CD patients. A significant association was reported concerning the genotype Ins/Ins for young-onset CD patients (P = 0.029, OR = 3.257, 95% CI: 1.08-9.77). We observed also a significant increase in sHLA-G measured by ELISA in CD patients compared to controls (P = 0.002). The 14-bp Del/Del and 14-bp Del/Ins genotypes are the high HLA-G producers. Among sHLA-G(positive) patients, 43% of subjects present dimers of HLA-G. The presence of dimers seems to be related to the advanced stages of the disease. The 14-bp Del/Ins polymorphism is associated with an increased risk of CD particularly in young-onset CD patients and controls sHLA-G plasma levels. Dimers of sHLA-G are frequent in advanced disease stages. The above findings indicate that the genetic 14-bp Del/Ins polymorphism in exon 8 of the HLA-G gene is associated with the risk of CD and suggest a role for sHLA-G as a prognostic marker for progressive disease. PMID:25577194

  1. Distinctive profiles of small RNA couple inverted repeat-induced post-transcriptional gene silencing with endogenous RNA silencing pathways in Arabidopsis

    PubMed Central

    Matvienko, Marta; Piskurewicz, Urszula; Xu, Huaqin; Martineau, Belinda; Wong, Joan; Govindarajulu, Manjula; Kozik, Alexander; Michelmore, Richard W.

    2014-01-01

    The experimental induction of RNA silencing in plants often involves expression of transgenes encoding inverted repeat (IR) sequences to produce abundant dsRNAs that are processed into small RNAs (sRNAs). These sRNAs are key mediators of post-transcriptional gene silencing (PTGS) and determine its specificity. Despite its application in agriculture and broad utility in plant research, the mechanism of IR-PTGS is incompletely understood. We generated four sets of 60 Arabidopsis plants, each containing IR transgenes expressing different configurations of uidA and CHALCONE SYNTHASE (At-CHS) gene fragments. Levels of PTGS were found to depend on the orientation and position of the fragment in the IR construct. Deep sequencing and mapping of sRNAs to corresponding transgene-derived and endogenous transcripts identified distinctive patterns of differential sRNA accumulation that revealed similarities among sRNAs associated with IR-PTGS and endogenous sRNAs linked to uncapped mRNA decay. Detailed analyses of poly-A cleavage products from At-CHS mRNA confirmed this hypothesis. We also found unexpected associations between sRNA accumulation and the presence of predicted open reading frames in the trigger sequence. In addition, strong IR-PTGS affected the prevalence of endogenous sRNAs, which has implications for the use of PTGS for experimental or applied purposes. PMID:25344399

  2. Identification of miniature inverted-repeat transposable elements (MITEs) and biogenesis of their siRNAs in the Solanaceae: New functional implications for MITEs

    PubMed Central

    Kuang, Hanhui; Padmanabhan, Chellappan; Li, Feng; Kamei, Ayako; Bhaskar, Pudota B.; Ouyang, Shu; Jiang, Jiming; Buell, C. Robin; Baker, Barbara

    2009-01-01

    Small RNAs regulate the genome by guiding transcriptional and post-transcriptional silencing machinery to specific target sequences, including genes and transposable elements (TEs). Although miniature inverted-repeat transposable elements (MITEs) are closely associated with euchromatic genes, the broader functional impact of these short TE insertions in genes is largely unknown. We identified 22 families of MITEs in the Solanaceae (MiS1–MiS22) and found abundant MiS insertions in Solanaceae genomic DNA and expressed sequence tags (EST). Several Solanaceae MITEs generate genome changes that potentially affect gene function and regulation, most notably, a MiS insertion that provides a functionally indispensable alternative exon in the tobacco mosaic virus N resistance gene. We show that MITEs generate small RNAs that are primarily 24 nt in length, as detected by Northern blot hybridization and by sequencing small RNAs of Solanum demissum, Nicotiana glutinosa, and Nicotiana benthamiana. Additionally, we show that stable RNAi lines silencing DICER-LIKE3 (DCL3) in tobacco and RNA-dependent RNA polymerase 2 (RDR2) in potato cause a reduction in 24-nt MITE siRNAs, suggesting that, as in Arabidopsis, TE-derived siRNA biogenesis is DCL3 and RDR2 dependent. We provide evidence that DICER-LIKE4 (DCL4) may also play a role in MITE siRNA generation in the Solanaceae. PMID:19037014

  3. Sinorhizobium fredii HH103 bacteroids are not terminally differentiated and show altered O-antigen in nodules of the Inverted Repeat-Lacking Clade legume Glycyrrhiza uralensis.

    PubMed

    Crespo-Rivas, Juan C; Guefrachi, Ibtissem; Mok, Kenny C; Villaécija-Aguilar, José A; Acosta-Jurado, Sebastián; Pierre, Olivier; Ruiz-Sainz, José E; Taga, Michiko E; Mergaert, Peter; Vinardell, José M

    2016-09-01

    In rhizobial species that nodulate inverted repeat-lacking clade (IRLC) legumes, such as the interaction between Sinorhizobium meliloti and Medicago, bacteroid differentiation is driven by an endoreduplication event that is induced by host nodule-specific cysteine rich (NCR) antimicrobial peptides and requires the participation of the bacterial protein BacA. We have studied bacteroid differentiation of Sinorhizobium fredii HH103 in three host plants: Glycine max, Cajanus cajan and the IRLC legume Glycyrrhiza uralensis. Flow cytometry, microscopy analyses and viability studies of bacteroids as well as confocal microscopy studies carried out in nodules showed that S. fredii HH103 bacteroids, regardless of the host plant, had deoxyribonucleic acid (DNA) contents, cellular sizes and survival rates similar to those of free-living bacteria. Contrary to S. meliloti, S. fredii HH103 showed little or no sensitivity to Medicago NCR247 and NCR335 peptides. Inactivation of S. fredii HH103 bacA neither affected symbiosis with Glycyrrhiza nor increased bacterial sensitivity to Medicago NCRs. Finally, HH103 bacteroids isolated from Glycyrrhiza, but not those isolated from Cajanus or Glycine, showed an altered lipopolysaccharide. Our studies indicate that, in contrast to the S. meliloti-Medicago model symbiosis, bacteroids in the S. fredii HH103-Glycyrrhiza symbiosis do not undergo NCR-induced and bacA-dependent terminal differentiation. PMID:26521863

  4. Modulation of ccrAB Expression and SCCmec Excision by an Inverted Repeat Element and SarS in Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Zhang, Shijie; Ma, Ronghua; Liu, Xiaoyu; Zhang, Xu

    2015-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a notorious human pathogen that can cause a broad spectrum of infections. MRSA strains are resistant to almost the entire family of β-lactam antibiotics due to the acquisition of staphylococcal cassette chromosome mec (SCCmec). The chromosome cassette recombinases A and B, encoded by ccrAB genes located on SCCmec, play a key role in the excision of SCCmec. Studies have shown that ccrAB genes are expressed in only a minority of cells, suggesting the involvement of a subtle regulatory mechanism in ccrAB expression which has not been uncovered. Here, we found that an inverted repeat (IR) element, existing extensively and conservatively within the ccrAB promoter of different SCCmec types, played a repressive role in ccrAB expression and SCCmec excision in MRSA strain N315. Replacement of the IR sequence led to a significant increase in ccrAB expression and curing of SCCmec from strain N315 cells. In addition, we identified the transcriptional regulator SarS using DNA-affinity chromatography and further demonstrated that SarS can bind to the IR sequence and upregulate ccrAB expression and SCCmec excision. These findings reveal a molecular mechanism regulating ccrAB expression and SCCmec excision and may provide mechanic insights into the lateral transfer of SCCmec and spread of antibiotic resistance in S. aureus. PMID:26248371

  5. Recent, extensive, and preferential insertion of members of the miniature inverted-repeat transposable element family Heartbreaker into genic regions of maize

    PubMed Central

    Zhang, Qiang; Arbuckle, John; Wessler, Susan R.

    2000-01-01

    A 314-bp DNA element called Heartbreaker-hm1 (Hbr-hm1) was previously identified in the 3′ untranslated region of a mutant allele of the maize disease resistance gene HM1. This element has structural features of miniature inverted-repeat transposable elements (MITEs) and is a member of a large family of approximately 4,000 copies in the maize genome. Unlike previously described MITEs, most members of the Hbr family display over 90% sequence identity. This, coupled with the insertion of an Hbr element into an allele of the HM1 gene, suggested that this family might have spread recently throughout the genome. Consistent with this view is the finding that Hbr insertion sites are remarkably polymorphic. Ten of ten loci containing Hbr elements were found to be polymorphic for the presence or absence of Hbr among a collection of maize inbred lines and teosinte strains. Despite the fact that over 80% of the maize genome contain moderate to highly repetitive DNA, we find that randomly chosen Hbr elements are predominantly in single or low copy regions. Furthermore, when used to query both the public and private databases of plant genes, over 50% of the sequences flanking these Hbr elements resulted in significant “hits.” Taken together, these data indicate that the presence or absence of Hbr elements is a significant contributory factor to the high level of polymorphism associated with maize genic regions. PMID:10655501

  6. Distinctive profiles of small RNA couple inverted repeat-induced post-transcriptional gene silencing with endogenous RNA silencing pathways in Arabidopsis.

    PubMed

    Wroblewski, Tadeusz; Matvienko, Marta; Piskurewicz, Urszula; Xu, Huaqin; Martineau, Belinda; Wong, Joan; Govindarajulu, Manjula; Kozik, Alexander; Michelmore, Richard W

    2014-12-01

    The experimental induction of RNA silencing in plants often involves expression of transgenes encoding inverted repeat (IR) sequences to produce abundant dsRNAs that are processed into small RNAs (sRNAs). These sRNAs are key mediators of post-transcriptional gene silencing (PTGS) and determine its specificity. Despite its application in agriculture and broad utility in plant research, the mechanism of IR-PTGS is incompletely understood. We generated four sets of 60 Arabidopsis plants, each containing IR transgenes expressing different configurations of uidA and CHALCONE Synthase (At-CHS) gene fragments. Levels of PTGS were found to depend on the orientation and position of the fragment in the IR construct. Deep sequencing and mapping of sRNAs to corresponding transgene-derived and endogenous transcripts identified distinctive patterns of differential sRNA accumulation that revealed similarities among sRNAs associated with IR-PTGS and endogenous sRNAs linked to uncapped mRNA decay. Detailed analyses of poly-A cleavage products from At-CHS mRNA confirmed this hypothesis. We also found unexpected associations between sRNA accumulation and the presence of predicted open reading frames in the trigger sequence. In addition, strong IR-PTGS affected the prevalence of endogenous sRNAs, which has implications for the use of PTGS for experimental or applied purposes. PMID:25344399

  7. HLA-G 14-bp Ins/Ins Genotype in Patients Harbouring Helicobacter pylori Infection: A Potential Risk Factor?

    PubMed

    Genre, J; Reginaldo, F P Santos; Andrade, J Marco de Leon; Lima, F P; da Camara, A V Coutinho; Donadi, E A; Crispim, J C

    2016-01-01

    H. pylori is a potent pathogen due to its capacity to successfully evade host defence mechanisms. Despite inducing immune responses in infected individuals, sometimes these responses fail to clear the infection and the bacterium establishes a persistent infection leading to chronic inflammation. In this context, we hypothesized that human leucocyte antigen G (HLA-G), a non-classical major histocompatibility complex molecule that has the ability to regulate immune responses both in physiological and in pathological conditions, may play an important role in promoting tolerance and helping H. pylori to subvert host defence and consequently establish a chronic infection. Therefore, we evaluated the expression of HLA-G 14-bp Ins/Del polymorphism in patients harbouring H. pylori infection, as well as their relationship with histological and demographic variables, to gain a better understanding of the actual role of HLA-G and its genetic polymorphisms in bacterial infection. Sixty-eight patients with clinical symptoms suggestive of H. pylori infection were enrolled to assess HLA-G 14-bp Ins/Del polymorphism allele and genotype frequencies. After adjustment for covariates (age and gender), the odds of having the genotype Ins/Ins, compared to Del/Del, were 3.77 times greater among HP+ cases than among controls. These findings suggest that the 14-bp Ins/Ins genotype, already associated with inflammatory and autoimmune diseases as well as some viral and parasitic infections, could confer a greater risk of developing H. pylori infection. PMID:26368842

  8. The association between the HLA-G 14-bp insertion/deletion polymorphism and type 1 diabetes.

    PubMed

    Silva, H P V; Ururahy, M A G; Souza, K S C; Loureiro, M B; Oliveira, Y M C; Oliveira, G H M; Luchessi, A D; Carvalho, K T C; Freitas, J C O C; Donadi, E A; Hirata, R D C; Almeida, M G; Arrais, R F; Hirata, M H; Rezende, A A

    2016-01-01

    Type 1 diabetes (T1D) is a multifactorial disease that has a strong genetic component. The HLA-G is a nonclassical HLA class I locus that is associated with immunomodulatory functions, including downregulation of innate and adaptive immune responses and induction of immune tolerance. However, there is currently limited information about the involvement of HLA-G in T1D susceptibility. This case-control study aims to investigate the T1D susceptibility association of alleles and genotypes of a widely investigated 14-bp insertion/deletion polymorphism in the HLA-G and to provide further evidence of the frequency distribution of class II HLA-DR-DQ-risk genotypes in T1D children and adolescents in the Brazilian population. The deletion allele and the homozygous deletion genotype are associated with susceptibility to T1D and the insertion allele and the heterozygous deletion/insertion genotype are associated with protection from T1D. We also confirm that genetic susceptibility to T1D is associated with the DRB1*03:01-DQA1*05:01-DQB1*02:01 and DRB1*04-DQA1*03:01-DQB1*03:02 haplotypes in Brazilian northeast region. The DR3-DQ2/DR4-DQ8 genotype conferred the highest detected risk for T1D. Our results identify a novel association of the 14-bp deletion allele and the homozygous deletion genotype with T1D development and provide additional evidence of the importance of HLA class II heterozygous DR3-DQ2/DR4-DQ8 genotype in T1D susceptibility. PMID:26492519

  9. The Hermes transposable element from the house fly, Musca domestica, is a short inverted repeat-type element of the hobo, Ac, and Tam3 (hAT) element family.

    PubMed

    Warren, W D; Atkinson, P W; O'Brochta, D A

    1994-10-01

    The genome of the house fly, Musca domestica, contains an active transposable element system, called Hermes. Using PCR and inverse PCR we amplified and sequenced overlapping segments of several Hermes elements and from these data we have constructed a 2749 bp consensus Hermes DNA sequence. Hermes termini are composed of 17 bp imperfect inverted repeats that are almost identical to the inverted terminal repeats of the hobo element of Drosophila melanogaster. Full length Hermes elements contain a single long ORF capable of encoding a protein of 612 amino acids which is 55% identical to the amino acid sequence of the hobo transposase. Comparison of the ends of the Hermes and hobo elements to those of the Ac element of Zea mays, and the Tam3 element of Antirrhinum majus, as well as several other plant and insect elements, revealed a conserved terminal sequence motif. Thus Hermes is clearly a member of the hobo, Ac and Tam3 (hAT) transposable element family, other members of which include the Tag1 element from Arabidopsis thaliana and the Bg element from Zea mays. The evolution of this class of transposable elements and the potential utility of Hermes as a genetic tool in M. domestica and related species are discussed. PMID:7813905

  10. Transition from a heterozygous to a homozygous state of a pair of loci in the inverted repeat sequences of the L component of the herpes simplex virus type 1 genome.

    PubMed Central

    Umene, K

    1987-01-01

    The behavior of herpes simplex virus type 1 heterozygous isolates, in which the two inverted repeats of the L component (RL) were differentiated by a polymorphism marker (the presence [type B] or absence [type A] of a SalI site), was investigated. The progeny viruses derived from the heterozygote (A/B) consisted of heterozygotes (A/B), type A homozygotes (A/A), and type B homozygotes (B/B). The heterology between RL, albeit tolerated, was unstable, as is the case with heterology between the repeats of the S component. The two repeats TRL (terminal) and IRL (internal) were equipotent in generating homozygotes from a heterozygote. Data obtained from an analysis of 426 progeny viruses derived from heterozygous clones supported the hypothesis that the two loci in RL of a herpes simplex virus type 1 genome are determined as a random combination of the corresponding two loci in RL of the parent virus and that the ratio of heterozygotes/type A homozygotes/type B homozygotes in the progeny viruses from a heterozygote is expected to be 2:1:1. An ephemeral dominance of one type of homozygote over the other was observed in subclones from several heterozygous clones. Images PMID:3029414

  11. The characteristics and functions of a miniature inverted-repeat transposable element TaMITE81 in the 5' UTR of TaCHS7BL from Triticum aestivum.

    PubMed

    Xi, Xinyuan; Li, Na; Li, Shiming; Chen, Wenjie; Zhang, Bo; Liu, Baolong; Zhang, Huaigang

    2016-10-01

    Miniature inverted-repeat transposable elements (MITEs) are truncated derivatives of autonomous DNA transposons, and are dispersed abundantly in eukaryotic and prokaryotic genomes. In this article, a MITE, TaMITE81, was isolated from the 5' untranslated region (UTR) of TaCHS7BL, chalcone synthase (CHS) catalyzing the first committed step of anthocyanin biosynthesis, in the wheat cultivar 'Opata' with white grain. TaMITE81 was only 81 nucleotides, including a terminal inverted repeat with 39 nucleotides and was flanked by two nucleotides, "TA", target site duplications that were typical features of stowaway-like MITEs. Compared with the wheat cultivar 'Gy115' with purple grain, which is without the insertion, the expression of TaCHS7BL was lower in several organs of 'Opata'. The insertion of TaMITE81 into the 5' UTR of the GUS gene also reduced the transient expression of GUS on the coleoptiles of 'Opata', which means the insertion of TaMITE81 was the reason for the low expression of TaCHS7BL in 'Opata'. But the genotype of TaCHS7BL was not linked to phenotype of grain color in the RILs derived from a cross 'Gy115' and 'Opata'. The TaMITE81 density of the hexaploid variety of T. aestivum was more than 10 times that of diploid relatives, which implies that polyploidization caused the amplification of TaMITE81 homologous sequences. Further research should be conducted on decoding the relationship between TaCHS7BL and other traits relative to anthocyanin biosynthesis in wheat, and discovering the mechanism of TaMITE81 transposon action. PMID:27481288

  12. Meta-analysis of the human leukocyte antigen-G (HLA-G) 14 bp insertion/deletion polymorphism as a risk factor for preeclampsia.

    PubMed

    Pabalan, N; Jarjanazi, H; Sun, C; Iversen, A C

    2015-09-01

    The non-classical major histocompatibility complex, human leukocyte antigen (HLA)-G, plays an important role in pregnancy. HLA-G mediates proper interaction between maternal immune cells and fetal trophoblasts invading the uterine wall, to ensure successful placental development and function. Several HLA-G gene variants have been shown to be associated with development of preeclampsia (PE), but the reported associations of the HLA-G 14 base pair (bp) insertion/deletion (I/D) polymorphism (rs66554220) with PE are inconsistent. In this meta-analysis of HLA-G 14 bp I/D in each member of the family triad, we estimated risk (odds ratio [OR], 95% confidence interval) of associations with PE based on nine published offspring, nine mother and three father case-control studies. No significant increased risk associations between PE and HLA-G 14 bp I/D were detected in any of the family triad members (offspring: OR = 1.08-1.21, P = 0.57-0.74; mothers: OR = 1.11-1.28, P = 0.07-0.44; fathers: OR = 1.09-1.65, P = 0.07-0.70). Of the 20 comparisons performed, 14 (70%) were non-heterogeneous and seven of these had zero heterogeneity (I(2) = 0%). Sensitivity treatment confirmed robustness for the overall lack of association for HLA-G 14 bp I/D. In subgroup analysis, significant association between HLA-G 14 bp I/D and PE was shown in offspring from primipara (OR = 1.66-1.95, P = 0.04) and European Caucasian pregnancies (OR = 1.37-2.03, P = 0.02-0.03). However, heterogeneity and sensitivity tests suggest that further investigation is needed to determine if HLA-G 14 bp I/D is involved in trophoblast HLA-G expression and PE development in these subgroups. PMID:26202804

  13. The 14 bp Del/Ins HLA-G Polymorphism Is Related with High Blood Pressure in Acute Coronary Syndrome and Type 2 Diabetes Mellitus

    PubMed Central

    García-González, Ilian Janet; Valle, Yeminia; Rivas, Fernando; Figuera-Villanueva, Luis Eduardo; Muñoz-Valle, José Francisco; Flores-Salinas, Hector Enrique; Gutiérrez-Amavizca, Bianca Ethel; Dávalos-Rodríguez, Nory Omayra; Padilla-Gutiérrez, Jorge Ramón

    2014-01-01

    Immunologic and inflammatory processes are involved in the pathogenesis of acute coronary syndrome (ACS) and type 2 diabetes mellitus (DM2). Human leukocyte antigen-G (HLA-G) is a negative regulator of the immune response. This study evaluates the 14 bp Del/Ins HLA-G polymorphism in ACS and DM2. Three hundred and seventy individuals from Western Mexico were recruited and categorized into three groups: ACS (86), DM2 without coronary complications (70), and healthy subjects (214). Genotyping of the 14 bp Del/Ins HLA-G polymorphism was performed by PCR and Native-PAGE. The most common risk factors were hypertension and overweight in ACS and DM2, respectively. The genetic distribution of the 14 bp Del/Ins HLA-G polymorphism showed no significant differences between groups (P ≥ 0.23). Nonetheless, the Ins/Ins genotype was associated with high blood pressure (HBP) in the DM2 group (ORc = 1.65, P = 0.02). The genetic recessive model showed similar findings (ORc = 3.03, P = 0.04). No association was found in ACS, with a P of 0.05; nevertheless, the prevalence of Ins/Ins carriers was quite similar to that found in the DM2-HBP group. The 14 bp Del/Ins HLA-G polymorphism was not a susceptibility factor for ACS or DM2; however, the Ins/Ins genotype might have contributed to the development of HBP in the studied groups. PMID:24689061

  14. Seven New Complete Plastome Sequences Reveal Rampant Independent Loss of the ndh Gene Family across Orchids and Associated Instability of the Inverted Repeat/Small Single-Copy Region Boundaries

    PubMed Central

    Moore, Michael J.; Neubig, Kurt M.; Williams, Norris H.; Whitten, W. Mark; Kim, Joo-Hwan

    2015-01-01

    Earlier research has revealed that the ndh loci have been pseudogenized, truncated, or deleted from most orchid plastomes sequenced to date, including in all available plastomes of the two most species-rich subfamilies, Orchidoideae and Epidendroideae. This study sought to resolve deeper-level phylogenetic relationships among major orchid groups and to refine the history of gene loss in the ndh loci across orchids. The complete plastomes of seven orchids, Oncidium sphacelatum (Epidendroideae), Masdevallia coccinea (Epidendroideae), Sobralia callosa (Epidendroideae), Sobralia aff. bouchei (Epidendroideae), Elleanthus sodiroi (Epidendroideae), Paphiopedilum armeniacum (Cypripedioideae), and Phragmipedium longifolium (Cypripedioideae) were sequenced and analyzed in conjunction with all other available orchid and monocot plastomes. Most ndh loci were found to be pseudogenized or lost in Oncidium, Paphiopedilum and Phragmipedium, but surprisingly, all ndh loci were found to retain full, intact reading frames in Sobralia, Elleanthus and Masdevallia. Character mapping suggests that the ndh genes were present in the common ancestor of orchids but have experienced independent, significant losses at least eight times across four subfamilies. In addition, ndhF gene loss was correlated with shifts in the position of the junction of the inverted repeat (IR) and small single-copy (SSC) regions. The Orchidaceae have unprecedented levels of homoplasy in ndh gene presence/absence, which may be correlated in part with the unusual life history of orchids. These results also suggest that ndhF plays a role in IR/SSC junction stability. PMID:26558895

  15. Stream, Inverted

    NASA Technical Reports Server (NTRS)

    2006-01-01

    27 July 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the inverted, eroded remains of a channel -- now standing as a complex ridge that runs across the middle of this scene -- in dust-mantled terrain west of Sinus Meridiani, Mars. The original channel might have been carved by running water, but too little detail remains today to provide any certainty as to whether water was the culprit.

    Location near: 5.6oN, 7.6oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Northern Spring

  16. Power inverters

    SciTech Connect

    Miller, David H.; Korich, Mark D.; Smith, Gregory S.

    2011-11-15

    Power inverters include a frame and a power module. The frame has a sidewall including an opening and defining a fluid passageway. The power module is coupled to the frame over the opening and includes a substrate, die, and an encasement. The substrate includes a first side, a second side, a center, an outer periphery, and an outer edge, and the first side of the substrate comprises a first outer layer including a metal material. The die are positioned in the substrate center and are coupled to the substrate first side. The encasement is molded over the outer periphery on the substrate first side, the substrate second side, and the substrate outer edge and around the die. The encasement, coupled to the substrate, forms a seal with the metal material. The second side of the substrate is positioned to directly contact a fluid flowing through the fluid passageway.

  17. Stepped sinewave inverter

    NASA Astrophysics Data System (ADS)

    Appelbaum, J.; Gabbay, D.

    1984-11-01

    A stepped sinewave dc/ac inverter was analyzed for an inductive load with respect to load current and voltage, harmonics, power factor, and efficiency. This special inverter of high efficiency and low harmonic content is constructed by synthesizing the sinusoidal output by discrete voltage sources, such as storage batteries, solar cell, etc., with electronic switching of the sources at specific time intervals. The switching times are determined for the condition of minimum distortion of the synthesized wave. A 50 W inverter was built and tested to demonstrate this approach.

  18. Multilevel DC link inverter

    DOEpatents

    Su, Gui-Jia

    2003-06-10

    A multilevel DC link inverter and method for improving torque response and current regulation in permanent magnet motors and switched reluctance motors having a low inductance includes a plurality of voltage controlled cells connected in series for applying a resulting dc voltage comprised of one or more incremental dc voltages. The cells are provided with switches for increasing the resulting applied dc voltage as speed and back EMF increase, while limiting the voltage that is applied to the commutation switches to perform PWM or dc voltage stepping functions, so as to limit current ripple in the stator windings below an acceptable level, typically 5%. Several embodiments are disclosed including inverters using IGBT's, inverters using thyristors. All of the inverters are operable in both motoring and regenerating modes.

  19. Reliable inverter systems

    NASA Technical Reports Server (NTRS)

    Nagano, S.

    1979-01-01

    Base driver with common-load-current feedback protects paralleled inverter systems from open or short circuits. Circuit eliminates total system oscillation that can occur in conventional inverters because of open circuit in primary transformer winding. Common feedback signal produced by functioning modules forces operating frequency of failed module to coincide with clock drive so module resumes normal operating frequency in spite of open circuit.

  20. The plasma levels of soluble HLA-G molecules correlate directly with CD34+ cell concentration and HLA-G 14bp insertion/insertion polymorphism in cord blood donors

    PubMed Central

    Capittini, Cristina; Bergamaschi, Paola; Sachetto, Sara; Truglio, Mariarosa; Viola, Monica; Marchesi, Andrea; Genovese, Valeria; Romano, Bina; Guarene, Marco; Poma, Rossella; Martinetti, Miryam; Tinelli, Carmine; Salvaneschi, Laura

    2014-01-01

    Background Cord blood provides haematopoietic stem cells for allogeneic transplantation and, thanks to the naivety of its immune system, has several advantages over other sources of stem cells. In the transplantation setting, the presence of immunosuppressive human leucocyte antigen (HLA)-G molecules has been advocated to prevent both rejection and Graft-versus-Host disease. HLA-G is physiologically expressed throughout pregnancy and is contained in cord blood at birth. Moreover, it has recently been reported that not only cord blood mesenchymal cells, but also CD34+ cell progenies produce soluble HLA-G (sHLA-G). We tried to identify the largest producer of sHLA-G among 85 healthy cord blood donors at Pavia Cord Blood Bank, correlating the sHLA-G concentration with the HLA-G 14bp insertion/deletion (INS/DEL) genotype and CD34+ cell concentration. Materials and methods We measured sHLA-G levels in 36 cord blood plasma stored at −20 °C for 2 months and 49 cord blood plasma stored at −196 °C for 4–6 years, by enzyme-linked immunosorbent assay. All cord blood donors were genotyped for the HLA-G 14bp INS/DEL polymorphism by polymerase chain reaction. For each cord blood unit, we measured the cell concentration by flow cytometry. Results We did not find differences in sHLA-G levels between cord blood plasma aliquots stored for 4–6 years at −196 °C and cord blood plasma aliquots stored for 2 months at −20 °C. We observed a higher sHLA-G concentration in cord blood plasma donors who carried the HLA-G 14bp INS/INS genotype and had higher CD34+ cell concentrations (P =0.006). Discussion This is the first report showing that the best cord blood stem cell donor is also the best sHLA-G producer, particularly if genetically characterized by the HLA-G 14bp INS/INS genotype. If the therapeutic role of sHLA-G molecules were to be finally established in the transplantation setting, our data suggest that cord blood plasma donors can provide a safe source of allogeneic

  1. Resonant snubber inverter

    DOEpatents

    Lai, J.S.; Young, R.W. Sr.; Chen, D.; Scudiere, M.B.; Ott, G.W. Jr.; White, C.P.; McKeever, J.W.

    1997-06-24

    A resonant, snubber-based, soft switching, inverter circuit achieves lossless switching during dc-to-ac power conversion and power conditioning with minimum component count and size. Current is supplied to the resonant snubber branches solely by the main inverter switches. Component count and size are reduced by use of a single semiconductor switch in the resonant snubber branches. Component count is also reduced by maximizing the use of stray capacitances of the main switches as parallel resonant capacitors. Resonance charging and discharging of the parallel capacitances allows lossless, zero voltage switching. In one embodiment, circuit component size and count are minimized while achieving lossless, zero voltage switching within a three-phase inverter. 14 figs.

  2. Resonant snubber inverter

    DOEpatents

    Lai, Jih-Sheng; Young, Sr., Robert W.; Chen, Daoshen; Scudiere, Matthew B.; Ott, Jr., George W.; White, Clifford P.; McKeever, John W.

    1997-01-01

    A resonant, snubber-based, soft switching, inverter circuit achieves lossless switching during dc-to-ac power conversion and power conditioning with minimum component count and size. Current is supplied to the resonant snubber branches solely by the main inverter switches. Component count and size are reduced by use of a single semiconductor switch in the resonant snubber branches. Component count is also reduced by maximizing the use of stray capacitances of the main switches as parallel resonant capacitors. Resonance charging and discharging of the parallel capacitances allows lossless, zero voltage switching. In one embodiment, circuit component size and count are minimized while achieving lossless, zero voltage switching within a three-phase inverter.

  3. Inverting the Achievement Pyramid

    ERIC Educational Resources Information Center

    White-Hood, Marian; Shindel, Melissa

    2006-01-01

    Attempting to invert the pyramid to improve student achievement and increase all students' chances for success is not a new endeavor. For decades, educators have strategized, formed think tanks, and developed school improvement teams to find better ways to improve the achievement of all students. Currently, the No Child Left Behind Act (NCLB) is…

  4. Energy-Saving Inverter

    NASA Technical Reports Server (NTRS)

    Rippel, W. E.; Edwards, D. B.

    1984-01-01

    Commutation by field-effect transistor allows more efficient operation. High voltage field-effect transistor (FET) controls silicon controlled rectifiers (SCR's). Circuit requires only one capacitor and one inductor in commutation circuit: simpler, more efficient, and more economical than conventional inverters. Adaptable to dc-to-dc converters.

  5. Program Predicts Nonlinear Inverter Performance

    NASA Technical Reports Server (NTRS)

    Al-Ayoubi, R. R.; Oepomo, T. S.

    1985-01-01

    Program developed for ac power distribution system on Shuttle orbiter predicts total load on inverters and node voltages at each of line replaceable units (LRU's). Mathematical model simulates inverter performance at each change of state in power distribution system.

  6. Milliwatt dc/dc Inverter

    NASA Technical Reports Server (NTRS)

    Mclyman, C. W.

    1983-01-01

    Compact dc/dc inverter uses single integrated-circuit package containing six inverter gates that generate and amplify 100-kHz square-wave switching signal. Square-wave switching inverts 10-volt local power to isolated voltage at another desired level. Relatively high operating frequency reduces size of filter capacitors required, resulting in small package unit.

  7. Inverting the Linear Algebra Classroom

    ERIC Educational Resources Information Center

    Talbert, Robert

    2014-01-01

    The inverted classroom is a course design model in which students' initial contact with new information takes place outside of class meetings, and students spend class time on high-level sense-making activities. The inverted classroom model is so called because it inverts or "flips" the usual classroom design where typically class…

  8. Inverter ratio failure detector

    NASA Technical Reports Server (NTRS)

    Wagner, A. P.; Ebersole, T. J.; Andrews, R. E. (Inventor)

    1974-01-01

    A failure detector which detects the failure of a dc to ac inverter is disclosed. The inverter under failureless conditions is characterized by a known linear relationship of its input and output voltages and by a known linear relationship of its input and output currents. The detector includes circuitry which is responsive to the detector's input and output voltages and which provides a failure-indicating signal only when the monitored output voltage is less by a selected factor, than the expected output voltage for the monitored input voltage, based on the known voltages' relationship. Similarly, the detector includes circuitry which is responsive to the input and output currents and provides a failure-indicating signal only when the input current exceeds by a selected factor the expected input current for the monitored output current based on the known currents' relationship.

  9. Inverted organic photovoltaic cells.

    PubMed

    Wang, Kai; Liu, Chang; Meng, Tianyu; Yi, Chao; Gong, Xiong

    2016-05-21

    The advance in lifestyle, modern industrialization and future technological revolution are always at high expense of energy consumption. Unfortunately, there exist serious issues such as limited storage, high cost and toxic contamination in conventional fossil fuel energy sources. Instead, solar energy represents a renewable, economic and green alternative in the future energy market. Among the photovoltaic technologies, organic photovoltaics (OPVs) demonstrate a cheap, flexible, clean and easy-processing way to convert solar energy into electricity. However, OPVs with a conventional device structure are still far away from industrialization mainly because of their short lifetime and the energy-intensive deposition of top metal electrode. To address the stability and cost issue simultaneously, an inverted device structure has been introduced into OPVs, bridging laboratory research with practical application. In this review, recent progress in device structures, working mechanisms, functions and advances of each component layer as well their correlations with the efficiency and stability of inverted OPVs are reviewed and illustrated. PMID:27087582

  10. Inverted organic photosensitive device

    SciTech Connect

    Forrest, Stephen R.; Tong, Xiaoran; Lee, Jun Yeob; Cho, Yong Joo

    2015-09-08

    There is disclosed a method for preparing the surface of a metal substrate. The present disclosure also relates to an organic photovoltaic device including a metal substrate made by such method. Also disclosed herein is an inverted photosensitive device including a stainless steel foil reflective electrode, an organic donor-acceptor heterojunction over the reflective electrode, and a transparent electrode over the donor-acceptor heterojunction.

  11. Inverted glass harp.

    PubMed

    Quinn, Daniel B; Rosenberg, Brian J

    2015-08-01

    We present an analytical treatment of the acoustics of liquid-filled wine glasses, or "glass harps." The solution is generalized such that under certain assumptions it reduces to previous glass harp models, but also leads to a proposed musical instrument, the "inverted glass harp," in which an empty glass is submerged in a liquid-filled basin. The versatility of the solution demonstrates that all glass harps are governed by a family of solutions to Laplace's equation around a vibrating disk. Tonal analyses of recordings for a sample glass are offered as confirmation of the scaling predictions. PMID:26382336

  12. Inverted glass harp

    NASA Astrophysics Data System (ADS)

    Quinn, Daniel B.; Rosenberg, Brian J.

    2015-08-01

    We present an analytical treatment of the acoustics of liquid-filled wine glasses, or "glass harps." The solution is generalized such that under certain assumptions it reduces to previous glass harp models, but also leads to a proposed musical instrument, the "inverted glass harp," in which an empty glass is submerged in a liquid-filled basin. The versatility of the solution demonstrates that all glass harps are governed by a family of solutions to Laplace's equation around a vibrating disk. Tonal analyses of recordings for a sample glass are offered as confirmation of the scaling predictions.

  13. Gas cooled traction drive inverter

    SciTech Connect

    Chinthavali, Madhu Sudhan

    2013-10-08

    The present invention provides a modular circuit card configuration for distributing heat among a plurality of circuit cards. Each circuit card includes a housing adapted to dissipate heat in response to gas flow over the housing. In one aspect, a gas-cooled inverter includes a plurality of inverter circuit cards, and a plurality of circuit card housings, each of which encloses one of the plurality of inverter cards.

  14. Gas cooled traction drive inverter

    DOEpatents

    Chinthavali, Madhu Sudhan

    2016-04-19

    The present invention provides a modular circuit card configuration for distributing heat among a plurality of circuit cards. Each circuit card includes a housing adapted to dissipate heat in response to gas flow over the housing. In one aspect, a gas-cooled inverter includes a plurality of inverter circuit cards, and a plurality of circuit card housings, each of which encloses one of the plurality of inverter cards.

  15. Applications of cascade multilevel inverters.

    PubMed

    Peng, Fang-zen; Qian, Zhao-ming

    2003-01-01

    Cascade multilevel inverters have been developed for electric utility applications. A cascade M-level inverter consists of (M-1)/2 H-bridges in which each bridge's dc voltage is supported by its own dc capacitor. The new inverter can: (1) generate almost sinusoidal waveform voltage while only switching one time per fundamental cycle; (2) dispense with multi-pulse inverters' transformers used in conventional utility interfaces and static var compensators; (3) enables direct parallel or series transformer-less connection to medium- and high-voltage power systems. In short, the cascade inverter is much more efficient and suitable for utility applications than traditional multi-pulse and pulse width modulation (PWM) inverters. The authors have experimentally demonstrated the superiority of the new inverter for power supply, (hybrid) electric vehicle (EV) motor drive, reactive power (var) and harmonic compensation. This paper summarizes the features, feasibility, and control schemes of the cascade inverter for utility applications including utility interface of renewable energy, voltage regulation, var compensation, and harmonic filtering in power systems. Analytical, simulated, and experimental results demonstrated the superiority of the new inverters. PMID:14566981

  16. Alternative algebras admitting derivations with invertible values and invertible derivations

    NASA Astrophysics Data System (ADS)

    Kaygorodov, I. B.; Popov, Yu S.

    2014-10-01

    We prove an analogue of the Bergen-Herstein-Lanski theorem for alternative algebras: describe all alternative algebras that admit derivations with invertible values. We also prove an analogue of Moens' theorem for alternative algebras (a finite-dimensional alternative algebra over a field of characteristic zero is nilpotent if and only if it admits an invertible Leibniz derivation).

  17. Inverted genomic segments and complex triplication rearrangements are mediated by inverted repeats in the human genome

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We identified complex genomic rearrangements consisting of intermixed duplications and triplications of genomic segments at the MECP2 and PLP1 loci. These complex rearrangements were characterized by a triplicated segment embedded within a duplication in 11 unrelated subjects. Notably, only two brea...

  18. Simplified High-Power Inverter

    NASA Technical Reports Server (NTRS)

    Edwards, D. B.; Rippel, W. E.

    1984-01-01

    Solid-state inverter simplified by use of single gate-turnoff device (GTO) to commutate multiple silicon controlled rectifiers (SCR's). By eliminating conventional commutation circuitry, GTO reduces cost, size and weight. GTO commutation applicable to inverters of greater than 1-kilowatt capacity. Applications include emergency power, load leveling, drives for traction and stationary polyphase motors, and photovoltaic-power conditioning.

  19. Repeating thermocouple

    SciTech Connect

    Falk, R. A.

    1985-06-04

    Disclosed herein is a repeating use thermocouple assembly and method of making the same in which a cavity adjacent the tip of the thermocouple is filled with a thermosetting foundry sand and baked in place to provide support for the thermocouple tube without causing stresses during use which could cause breakage of the thermocouple tube.

  20. Analysis of separate isolates of Bordetella pertussis repeated DNA sequences.

    PubMed

    McPheat, W L; Hanson, J H; Livey, I; Robertson, J S

    1989-06-01

    Two independent isolates of a Bordetella pertussis repeated DNA unit were sequenced and shown to be an insertion sequence element with five nucleotide differences between the two copies. The sequences were 1053 bp in length with near-perfect terminal inverted repeats of 28 bp, had three open reading frames, and were each flanked by short direct repeats. The two insertion sequences showed considerable homology to two other B. pertussis repeated DNA sequences reported recently: IS481 and a 530 bp repeated DNA unit. The B. pertussis insertion sequence would appear to comprise a group of closely related sequences differing mainly in flanking direct repeats and the terminal inverted repeats. The two isolates reported here, which were from the adenylate cyclase and agglutinogen 2 regions of the genome, were numbered IS48lvl and IS48lv2 respectively. PMID:2559151

  1. Nanowire NMOS Logic Inverter Characterization.

    PubMed

    Hashim, Yasir

    2016-06-01

    This study is the first to demonstrate characteristics optimization of nanowire N-Channel Metal Oxide Semiconductor (NW-MOS) logic inverter. Noise margins and inflection voltage of transfer characteristics are used as limiting factors in this optimization. A computer-based model used to produce static characteristics of NW-NMOS logic inverter. In this research two circuit configuration of NW-NMOS inverter was studied, in first NW-NMOS circuit, the noise margin for (low input-high output) condition was very low. For second NMOS circuit gives excellent noise margins, and results indicate that optimization depends on applied voltage to the inverter. Increasing gate to source voltage with (2/1) nanowires ratio results better noise margins. Increasing of applied DC load transistor voltage tends to increasing in decreasing noise margins; decreasing this voltage will improve noise margins significantly. PMID:27427653

  2. Inverter Ground Fault Overvoltage Testing

    SciTech Connect

    Hoke, Andy; Nelson, Austin; Chakraborty, Sudipta; Chebahtah, Justin; Wang, Trudie; McCarty, Michael

    2015-08-12

    This report describes testing conducted at NREL to determine the duration and magnitude of transient overvoltages created by several commercial PV inverters during ground fault conditions. For this work, a test plan developed by the Forum on Inverter Grid Integration Issues (FIGII) has been implemented in a custom test setup at NREL. Load rejection overvoltage test results were reported previously in a separate technical report.

  3. 21 CFR 184.1859 - Invert sugar.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Invert sugar. 184.1859 Section 184.1859 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DIRECT FOOD....1859 Invert sugar. (a) Invert sugar (CAS Reg. No. 8013-17-0) is an aqueous solution of inverted...

  4. Inverter design for high frequency power distribution

    NASA Technical Reports Server (NTRS)

    King, R. J.

    1985-01-01

    A class of simple resonantly commutated inverters are investigated for use in a high power (100 KW - 1000 KW) high frequency (10 KHz - 20 KHz) AC power distribution system. The Mapham inverter is found to provide a unique combination of large thyristor turn-off angle and good utilization factor, much better than an alternate 'current-fed' inverter. The effects of loading the Mapham inverter entirely with rectifier loads are investigated by simulation and with an experimental 3 KW 20 KHz inverter. This inverter is found to be well suited to a power system with heavy rectifier loading.

  5. Microgrid and Inverter Control and Simulator Software

    SciTech Connect

    2012-09-13

    A collection of software that can simulate the operation of an inverter on a microgrid or control a real inverter. In addition, it can simulate the control of multiple nodes on a microgrid." Application: Simulation of inverters and microgrids; control of inverters on microgrids." The MMI submodule is designed to control custom inverter hardware, and to simulate that hardware. The INVERTER submodule is only the simulator code, and is of an earlier generation than the simulator in MMI. The MICROGRID submodule is an agent-based simulator of multiple nodes on a microgrid which presents a web interface. The WIND submodule produces movies of wind data with a web interface.

  6. Advanced Modular Inverter Technology Development

    SciTech Connect

    Adam Szczepanek

    2006-02-04

    Electric and hybrid-electric vehicle systems require an inverter to convert the direct current (DC) output of the energy generation/storage system (engine, fuel cells, or batteries) to the alternating current (AC) that vehicle propulsion motors use. Vehicle support systems, such as lights and air conditioning, also use the inverter AC output. Distributed energy systems require an inverter to provide the high quality AC output that energy system customers demand. Today's inverters are expensive due to the cost of the power electronics components, and system designers must also tailor the inverter for individual applications. Thus, the benefits of mass production are not available, resulting in high initial procurement costs as well as high inverter maintenance and repair costs. Electricore, Inc. (www.electricore.org) a public good 501 (c) (3) not-for-profit advanced technology development consortium assembled a highly qualified team consisting of AeroVironment Inc. (www.aerovironment.com) and Delphi Automotive Systems LLC (Delphi), (www.delphi.com), as equal tiered technical leads, to develop an advanced, modular construction, inverter packaging technology that will offer a 30% cost reduction over conventional designs adding to the development of energy conversion technologies for crosscutting applications in the building, industry, transportation, and utility sectors. The proposed inverter allows for a reduction of weight and size of power electronics in the above-mentioned sectors and is scalable over the range of 15 to 500kW. The main objective of this program was to optimize existing AeroVironment inverter technology to improve power density, reliability and producibility as well as develop new topology to reduce line filter size. The newly developed inverter design will be used in automotive and distribution generation applications. In the first part of this program the high-density power stages were redesigned, optimized and fabricated. One of the main tasks

  7. Inverted Meckel's diverticulum preoperatively diagnosed using double-balloon enteroscopy.

    PubMed

    Takagaki, Kosuke; Osawa, Satoshi; Ito, Tatsuhiro; Iwaizumi, Moriya; Hamaya, Yasushi; Tsukui, Hiroe; Furuta, Takahisa; Wada, Hidetoshi; Baba, Satoshi; Sugimoto, Ken

    2016-05-01

    An inverted Meckel's diverticulum is a rare gastrointestinal congenital anomaly that is difficult to diagnose prior to surgery and presents with anemia, abdominal pain, or intussusception. Here, we report the case of 57-year-old men with an inverted Meckel's diverticulum, who was preoperatively diagnosed using double-balloon enteroscopy. He had repeatedly experienced epigastric pain for 2 mo. Ultrasonography and computed tomography showed intestinal wall thickening in the pelvis. Double-balloon enteroscopy via the anal route was performed for further examination, which demonstrated an approximately 8-cm, sausage-shaped, submucosal tumor located approximately 80 cm proximal to the ileocecal valve. A small depressed erosion was observed at the tip of this lesion. Forceps biopsy revealed heterotopic gastric mucosa. Thus, the patient was diagnosed with an inverted Meckel's diverticulum, and single-incision laparoscopic surgery was performed. This case suggests that an inverted Meckel's diverticulum should be considered as a differential diagnosis for a submucosal tumor in the ileum. Balloon-assisted enteroscopy with forceps biopsy facilitate a precise diagnosis of this condition. PMID:27158212

  8. Inverting an Introductory Statistics Classroom

    ERIC Educational Resources Information Center

    Kraut, Gertrud L.

    2015-01-01

    The inverted classroom allows more in-class time for inquiry-based learning and for working through more advanced problem-solving activities than does the traditional lecture class. The skills acquired in this learning environment offer benefits far beyond the statistics classroom. This paper discusses four ways that can make the inverted…

  9. Overload protection system for power inverter

    NASA Technical Reports Server (NTRS)

    Nagano, S. (Inventor)

    1977-01-01

    An overload protection system for a power inverter utilized a first circuit for monitoring current to the load from the power inverter to detect an overload and a control circuit to shut off the power inverter, when an overload condition was detected. At the same time, a monitoring current inverter was turned on to deliver current to the load at a very low power level. A second circuit monitored current to the load, from the monitoring current inverter, to hold the power inverter off through the control circuit, until the overload condition was cleared so that the control circuit may be deactivated in order for the power inverter to be restored after the monitoring current inverter is turned off completely.

  10. Update on SIC-Based Inverter Technology

    SciTech Connect

    Chinthavali, Madhu Sudhan; Zhang, Hui; Tolbert, Leon M; Ozpineci, Burak

    2009-01-01

    This paper presents a study of silicon carbide (SiC) technology which includes device characterization and modeling, inverter simulation, and test results for several prototype inverters. The static and dynamic characteristics of discrete devices and half bridge modules are presented. Test results of a 55 kW hybrid inverter with SiC Schottky diodes and an 18 kW all-SiC inverter using SiC JFETs and Schottky diodes are demonstrated.

  11. Improved Performance via the Inverted Classroom

    ERIC Educational Resources Information Center

    Weinstein, Randy D.

    2015-01-01

    This study examined student performance in an inverted thermodynamics course (lectures provided by video outside of class) compared to a traditional lecture class. Students in the inverted class performed better on their exams. Students in the bottom third of the inverted course showed the greatest improvement. These bottom third students had a C…

  12. 21 CFR 184.1859 - Invert sugar.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Invert sugar. 184.1859 Section 184.1859 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1859 Invert sugar. (a) Invert sugar (CAS Reg. No. 8013-17-0) is an...

  13. 21 CFR 184.1859 - Invert sugar.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Invert sugar. 184.1859 Section 184.1859 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1859 Invert sugar. (a) Invert sugar (CAS Reg. No. 8013-17-0) is an...

  14. 21 CFR 184.1859 - Invert sugar.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Invert sugar. 184.1859 Section 184.1859 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1859 Invert sugar. (a) Invert sugar (CAS Reg. No. 8013-17-0) is an...

  15. 21 CFR 184.1859 - Invert sugar.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Invert sugar. 184.1859 Section 184.1859 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1859 Invert sugar. (a) Invert sugar (CAS Reg. No. 8013-17-0) is an...

  16. Thermal Study of Inverter Components: Preprint

    SciTech Connect

    Sorensen, N. R.; Thomas, E. V.; Quintana, M. A.; Barkaszi, S.; Rosenthal, A.; Zhang, Z.; Kurtz, S.

    2012-06-01

    Thermal histories of inverter components were collected from operating inverters from several manufacturers and three locations. The data were analyzed to determine thermal profiles, the dependence on local conditions, and to assess the effect on inverter reliability. Inverter temperatures were shown to increase with the power dissipation of the inverters, follow diurnal and annual cycles, and have a dependence on wind speed. An accumulated damage model was applied to the temperature profiles and an example of using these data to predict reliability was explored.

  17. Fault-tolerant three-level inverter

    DOEpatents

    Edwards, John; Xu, Longya; Bhargava, Brij B.

    2006-12-05

    A method for driving a neutral point clamped three-level inverter is provided. In one exemplary embodiment, DC current is received at a neutral point-clamped three-level inverter. The inverter has a plurality of nodes including first, second and third output nodes. The inverter also has a plurality of switches. Faults are checked for in the inverter and predetermined switches are automatically activated responsive to a detected fault such that three-phase electrical power is provided at the output nodes.

  18. Evaluation of recent residential inverters

    SciTech Connect

    Nichols, B.E.

    1982-06-01

    Seven residential utility-interactive inverters for photovoltaic power systems have been evaluated at MIT Laboratory and at the Northeast Residential Experiment Station (NE RES). Two, a Windworks Gemini and an Abacus Sunverter, have been reported on previously. Reviewed here are five other inverters: Windworks Gemini 8-kW (dc) model with an ac filter to improve the output current waveform and power factor; Acheval Wind Electronics 10-kW (ac) model, Helionetics 6-kW (dc) model; and American Power Conversion 2-kW and 4-kW (ac) models. Input and output power, power factor, current waveform distortion, audio noise and radio frequency interference measurements were made at the NE RES and the results are presented.

  19. Integrated Inverter And Battery Charger

    NASA Technical Reports Server (NTRS)

    Rippel, Wally E.

    1988-01-01

    Circuit combines functions of dc-to-ac inversion (for driving ac motor in battery-powered vehicle) and ac-to-dc conversion (for charging battery from ac line when vehicle not in use). Automatically adapts to either mode. Design of integrated inverter/charger eliminates need for duplicate components, saves space, reduces weight and cost of vehicle. Advantages in other applications : load-leveling systems, standby ac power systems, and uninterruptible power supplies.

  20. Effective switching frequency multiplier inverter

    SciTech Connect

    Su, Gui-Jia; Peng, Fang Z.

    2007-08-07

    A switching frequency multiplier inverter for low inductance machines that uses parallel connection of switches and each switch is independently controlled according to a pulse width modulation scheme. The effective switching frequency is multiplied by the number of switches connected in parallel while each individual switch operates within its limit of switching frequency. This technique can also be used for other power converters such as DC/DC, AC/DC converters.

  1. The Inverted Snow Globe Shadow

    NASA Astrophysics Data System (ADS)

    Ribeiro, Jair Lúcio Prados

    2015-01-01

    Our high school optics course finishes with an assignment that students usually appreciate. They must take pictures of everyday situations representing optical phenomena such as reflection, refraction, or dispersion, and post them on Instagram.1 When the photos were presented to the class, one student revealed an intriguing photo, similar to Fig. 1, showing a snow globe exposed to sunlight and its inverted shadow. This paper offers an explanation of the problem, which occurs due to light refraction from the globe.

  2. Gripper deploying and inverting linkage

    DOEpatents

    Minichan, Richard L.; Killian, Mark A.

    1993-01-01

    An end effector deploying and inverting linkage. The linkage comprises an air cylinder mounted in a frame or tube, a sliding bracket next to the air cylinder, a stopping bracket depending from the frame and three, pivotally-attached links that are attached to the end effector and to each other in such a way as to be capable of inverting the end effector and translating it laterally. The first of the three links is a straight element that is moved up and down by the shaft of the air cylinder. The second link is attached at one end to the stopping bracket and to the side of the end effector at the other end. The first link is attached near the middle of the second, sharply angled link so that, as the shaft of the air cylinder moves up and down, the second link rotates about an axis perpendicular to the frame and inverts and translates the end effector. The rotation of the second link is stopped at both ends when the link engages stops on the stopping bracket. The third link, slightly angled, is attached to the sliding bracket at one end and to the end of the end effector at the other. The third helps to control the end effector in its motion.

  3. Gripper deploying and inverting linkage

    DOEpatents

    Minichan, R.L.; Killian, M.A.

    1993-03-02

    An end effector deploying and inverting linkage. The linkage comprises an air cylinder mounted in a frame or tube, a sliding bracket next to the air cylinder, a stopping bracket depending from the frame and three, pivotally-attached links that are attached to the end effector and to each other in such a way as to be capable of inverting the end effector and translating it laterally. The first of the three links is a straight element that is moved up and down by the shaft of the air cylinder. The second link is attached at one end to the stopping bracket and to the side of the end effector at the other end. The first link is attached near the middle of the second, sharply angled link so that, as the shaft of the air cylinder moves up and down, the second link rotates about an axis perpendicular to the frame and inverts and translates the end effector. The rotation of the second link is stopped at both ends when the link engages stops on the stopping bracket. The third link, slightly angled, is attached to the sliding bracket at one end and to the end of the end effector at the other. The third helps to control the end effector in its motion.

  4. Familial inverted duplication 7p

    SciTech Connect

    Schaefer, G.B.; Novak, K.; Steele, D.

    1995-03-27

    A 10-month-old female with developmental delay and failure to thrive was referred for genetic evaluation as part of an adoption assessment. Physical exam showed a mildly beaked nose and clinodactyly, but otherwise nothing remarkable. Chromosome analysis showed an inverted duplication of the p12.2{r_arrow}p13 portion of chromosome 7(46,XX,dup(7)(p13p12.2)). The proposita`s older brother, mother, and grandmother were cognitively delayed and had the same chromosome 7 duplication. A review of the literature showed no other cases involving this exact duplication. 5 refs., 3 figs., 1 tab.

  5. System and method for regulating resonant inverters

    DOEpatents

    Stevanovic, Ljubisa Dragoljub; Zane, Regan Andrew

    2007-08-28

    A technique is provided for direct digital phase control of resonant inverters based on sensing of one or more parameters of the resonant inverter. The resonant inverter control system includes a switching circuit for applying power signals to the resonant inverter and a sensor for sensing one or more parameters of the resonant inverter. The one or more parameters are representative of a phase angle. The resonant inverter control system also includes a comparator for comparing the one or more parameters to a reference value and a digital controller for determining timing of the one or more parameters and for regulating operation of the switching circuit based upon the timing of the one or more parameters.

  6. Microgrid and Inverter Control and Simulator Software

    2012-09-13

    A collection of software that can simulate the operation of an inverter on a microgrid or control a real inverter. In addition, it can simulate the control of multiple nodes on a microgrid." Application: Simulation of inverters and microgrids; control of inverters on microgrids." The MMI submodule is designed to control custom inverter hardware, and to simulate that hardware. The INVERTER submodule is only the simulator code, and is of an earlier generation than themore » simulator in MMI. The MICROGRID submodule is an agent-based simulator of multiple nodes on a microgrid which presents a web interface. The WIND submodule produces movies of wind data with a web interface.« less

  7. Multilevel Inverters for Electric Vehicle Applications

    SciTech Connect

    Habetler, T.G.; Peng, F.Z.; Tolbert, L.M.

    1998-10-22

    This paper presents multilevel inverters as an application for all-electric vehicle (EV) and hybrid-electric vehicle (HEV) motor drives. Diode-clamped inverters and cascaded H-bridge inverters, (1) can generate near-sinusoidal voltages with only fundamental frequency switching; (2) have almost no electromagnetic interference (EMI) and common-mode voltage; and (3) make an EV more accessible/safer and open wiring possible for most of an EV'S power system. This paper explores the benefits and discusses control schemes of the cascade inverter for use as an EV motor drive or a parallel HEV drive and the diode-clamped inverter as a series HEV motor drive. Analytical, simulated, and experimental results show the superiority of these multilevel inverters for this new niche.

  8. Finding and Characterizing Repeats in Plant Genomes.

    PubMed

    Nicolas, Jacques; Peterlongo, Pierre; Tempel, Sébastien

    2016-01-01

    Plant genomes contain a particularly high proportion of repeated structures of various types. This chapter proposes a guided tour of available software that can help biologists to look for these repeats and check some hypothetical models intended to characterize their structures. Since transposable elements are a major source of repeats in plants, many methods have been used or developed for this large class of sequences. They are representative of the range of tools available for other classes of repeats and we have provided a whole section on this topic as well as a selection of the main existing software. In order to better understand how they work and how repeats may be efficiently found in genomes, it is necessary to look at the technical issues involved in the large-scale search of these structures. Indeed, it may be hard to keep up with the profusion of proposals in this dynamic field and the rest of the chapter is devoted to the foundations of the search for repeats and more complex patterns. The second section introduces the key concepts that are useful for understanding the current state of the art in playing with words, applied to genomic sequences. This can be seen as the first stage of a very general approach called linguistic analysis that is interested in the analysis of natural or artificial texts. Words, the lexical level, correspond to simple repeated entities in texts or strings. In fact, biologists need to represent more complex entities where a repeat family is built on more abstract structures, including direct or inverted small repeats, motifs, composition constraints as well as ordering and distance constraints between these elementary blocks. In terms of linguistics, this corresponds to the syntactic level of a language. The last section introduces concepts and practical tools that can be used to reach this syntactic level in biological sequence analysis. PMID:26519414

  9. Inverted File Compression through Document Identifier Reassignment.

    ERIC Educational Resources Information Center

    Shieh, Wann-Yun; Chen, Tien-Fu; Shann, Jean Jyh-Jiun; Chung, Chung-Ping

    2003-01-01

    Discusses the use of inverted files in information retrieval systems and proposes a document identifier reassignment method to reduce the average gap values in an inverted file. Highlights include the d-gap technique; document similarity; heuristic algorithms; file compression; and performance evaluation from a simulation environment. (LRW)

  10. Inverted follicular keratosis successfully treated with imiquimod.

    PubMed

    Karadag, Ayse Serap; Ozlu, Emin; Uzuncakmak, Tugba Kevser; Akdeniz, Necmettin; Cobanoglu, Bengu; Oman, Berkant

    2016-01-01

    Inverted follicular keratosis is a rare benign tumor of the follicular infundibulum characterized by exo-endophytic growing. It is thought to be a rare variant of the seborrheic keratosis. The diagnosis of inverted follicular keratosis is generally established histopathologically because clinical differentiation from other lesions is difficult. Herein, we present one such rare case, successfully treated with topical 5% imiquimod cream. PMID:27294052

  11. Inverted follicular keratosis successfully treated with imiquimod

    PubMed Central

    Karadag, Ayse Serap; Ozlu, Emin; Uzuncakmak, Tugba Kevser; Akdeniz, Necmettin; Cobanoglu, Bengu; Oman, Berkant

    2016-01-01

    Inverted follicular keratosis is a rare benign tumor of the follicular infundibulum characterized by exo-endophytic growing. It is thought to be a rare variant of the seborrheic keratosis. The diagnosis of inverted follicular keratosis is generally established histopathologically because clinical differentiation from other lesions is difficult. Herein, we present one such rare case, successfully treated with topical 5% imiquimod cream. PMID:27294052

  12. Circuit controls transients in SCR inverters

    NASA Technical Reports Server (NTRS)

    Moore, E. T.; Wilson, T. G.

    1964-01-01

    Elimination of starting difficulties in SCR inverters is accomplished by the addition of two taps of the output winding of the inverter. On starting or under transient loads, the two additional taps deliver power through diodes without requiring quenching of SCR currents in excess of normal starting load.

  13. Nanostructured Inverted Organic Photovoltaic Cells

    NASA Astrophysics Data System (ADS)

    Thomas, Michael

    Organic photovoltaic cells (OPVs)are promising devices for inexpensive power generation from sunlight. Organic semiconductors, the basic materials for OPVs, can be fabricated using a broad range of fabrication technologies from vapor deposition to solution processing. Upon light absorption, a strongly bound exciton is generated which can diffuse to a donor-acceptor heterojunction. At this interface it can be dissociated into free charge carriers which can be collected by the device electrodes. A major challenge for OPVs are short exciton diffusion lengths of up to 20 nm. Morphology engineering is required in order to harvest the exciton before it recombines and improve OPV performance. This work focuses on the study of nanostructured morphologies for use in inverted architecture OPVs. Glancing angle deposition (GLAD)is employed to fabricate nanocolumnar acceptor films. Through combining these nanostructured C60 films with a conjugated polymer donor P3CBT and a small molecule 3-Q, inverted OPVs are fabricated with the goal to analyze effect of morphology engineering on device performance. A major challenge was that C60 were found to be soluble in most commonly used organic solvents such as dichlorobenzene or chloroform. Although this challenge has limited the donor choice and therefore has limited device performance, a significant effect of morphology engineering could be observed. All GLAD structured C60 OPVs outperformed state of the art architectures such as planar films and bulk heterojunctions fabricated with the same materials. For P3CBT in particular the GLAD structured devices exhibited a twofold increase in power conversion efficiency compared with bulk heterojunctions and a fourfold increase compared with planar devices. In a further study, the acceptor materials PTCDA and C60 were co-evaporated into a single film. PTCDA is stable against non-polar organic solvents while C60 provides a high electron mobility. Nanocolumnar acceptor blended PTCDA:C60 films

  14. Repeated Course Enrollments.

    ERIC Educational Resources Information Center

    Windham, Patricia

    This report resents tables of repeated course enrollment data in Florida community colleges for the fall 1993 cohort. Overall, the percent of repeats in college preparatory courses was greater than that of college credit courses. Within ICS codes, the highest percentage of credit repeat enrollments was in mathematics; the second highest was in…

  15. Switching Characteristics of Ferroelectric Transistor Inverters

    NASA Technical Reports Server (NTRS)

    Laws, Crystal; Mitchell, Coey; MacLeod, Todd C.; Ho, Fat D.

    2010-01-01

    This paper presents the switching characteristics of an inverter circuit using a ferroelectric field effect transistor, FeFET. The propagation delay time characteristics, phl and plh are presented along with the output voltage rise and fall times, rise and fall. The propagation delay is the time-delay between the V50% transitions of the input and output voltages. The rise and fall times are the times required for the output voltages to transition between the voltage levels V10% and V90%. Comparisons are made between the MOSFET inverter and the ferroelectric transistor inverter.

  16. Static Characteristics of the Ferroelectric Transistor Inverter

    NASA Technical Reports Server (NTRS)

    Mitchell, Cody; Laws, crystal; MacLeond, Todd C.; Ho, Fat D.

    2010-01-01

    The inverter is one of the most fundamental building blocks of digital logic, and it can be used as the foundation for understanding more complex logic gates and circuits. This paper presents the characteristics of an inverter circuit using a ferroelectric field-effect transistor. The voltage transfer characteristics are analyzed with respect to varying parameters such as supply voltage, input voltage, and load resistance. The effects of the ferroelectric layer between the gate and semiconductor are examined, and comparisons are made between the inverters using ferroelectric transistors and those using traditional MOSFETs.

  17. Inverted spectra of SWCNT films

    NASA Astrophysics Data System (ADS)

    Lehman, John; Hurst, Katherine; Roberson, Lara; Nield, Kathryn; Hamlin, John

    2008-03-01

    Diffuse Reflectance for purified single wall carbon nanotube (SWCNT) films and its relation to absorptance in the wavelength range 0.6 μm to 2 μm are inverted when compared to absorptivity data in the literature. This surprising behavior has been corroborated by diffuse reflectance measurements and shows that the reflectance is a substantial part of the unique optical behavior. Typically, the absorptance is fairly assumed to be complementary to the transmittance, while the reflectivity is insignificant. Only in certain instances (see for example, Barnes, et. al[1], Wang, et. al[2]), is the small reflectance explicitly accounted for. In the present work, we present diffuse reflectance and specular absorptance at normal incidence of SWCNT films. [1] T. M. Barnes, J. van de Lagemaat, D. Levi,1 G. Rumbles, T. J. Coutts, C. L. Weeks, D. A. Britz, I. Levitsky, J. Peltola, P. Glatkowski, Phys. Rev. B 75, 235410 (2007). [2] F. Wang, M. Y. Sfeir, L. Huang, X. M. H. Huang, Wu, J. Kim, J. Hone, S. O'Brien, L. E. Brus, T. F. Heinz, PRL 96, 167401 (2006).

  18. The Effect of Different Foot Orthosis Inverted Angles on Plantar Pressure in Children with Flexible Flatfeet

    PubMed Central

    Lee, Hyunkeun; Ahn, Soyoung; Song, Youngshin; Park, Insik

    2016-01-01

    Although orthotic modification using the inverted technique is available for the treatment of flatfoot, empirical evidence for the biomechanical effects of inverted-angle foot orthoses (FOs) is lacking. The aim of this study was to evaluate the effects of different FO inversion angles on plantar pressure during gait in children with flatfoot. Twenty-one children with flexible flatfeet (mean age 9.9 years) were enrolled in this study. The plantar pressures were measured for the rearfoot; medial and lateral midfoot; and medial, central, and lateral forefoot as participants walked on a treadmill while wearing shoes only and shoes with the following 3 orthotic conditions: (i) orthosis with no inverted angle, (ii) orthosis with a 15° inverted angle, and (iii) orthosis with a 30° inverted angle. A one-way repeated measures analysis of variance (ANOVA) with the Bonferroni-adjusted post-hoc test was used to compare the mean values of each orthotic condition. Compared with the shoe only condition, the peak pressure decreased significantly under the medial forefoot and rearfoot with all FOs (p <0.05). However, no significant differences in the peak pressure under the medial forefoot and rearfoot were observed between the FOs. The peak pressure under the medial midfoot increased significantly with all FOs, and a maximal increase in the peak pressure was obtained with a 30° inverted angle orthosis. Furthermore, the contact area under the medial midfoot and rearfoot increased significantly with all FOs, compared with the shoe only condition (p <0.05). Again, no significant differences were observed between the FOs. For plantar pressure redistribution, a FO with a low inverted angle could be effective, accommodative, and convenient for children with flatfoot. PMID:27458719

  19. Integrated Inverter For Driving Multiple Electric Machines

    DOEpatents

    Su, Gui-Jia [Knoxville, TN; Hsu, John S [Oak Ridge, TN

    2006-04-04

    An electric machine drive (50) has a plurality of inverters (50a, 50b) for controlling respective electric machines (57, 62), which may include a three-phase main traction machine (57) and two-phase accessory machines (62) in a hybrid or electric vehicle. The drive (50) has a common control section (53, 54) for controlling the plurality of inverters (50a, 50b) with only one microelectronic processor (54) for controlling the plurality of inverters (50a, 50b), only one gate driver circuit (53) for controlling conduction of semiconductor switches (S1-S10) in the plurality of inverters (50a, 50b), and also includes a common dc bus (70), a common dc bus filtering capacitor (C1) and a common dc bus voltage sensor (67). The electric machines (57, 62) may be synchronous machines, induction machines, or PM machines and may be operated in a motoring mode or a generating mode.

  20. Removing Barriers to Utility Interconnected Photovoltaic Inverters

    SciTech Connect

    Gonzalez, S.; Bonn, R.H.; Ginn, J.W.

    2000-10-03

    The Million Solar Roofs Initiative has motivated a renewed interest in the development of utility interconnected photovoltaic (UIPV) inverters. Government-sponsored programs (PVMaT, PVBONUS) and competition among utility interconnected inverter manufacturers have stimulated innovations and improved the performance of existing technologies. With this resurgence, Sandia National Laboratories (SNL) has developed a program to assist industry initiatives to overcome barriers to UIPV inverters. In accordance with newly adopted IEEE 929-2000, the utility interconnected PV inverters are required to cease energizing the utility grid when either a significant disturbance occurs or the utility experiences an interruption in service. Compliance with IEEE 929-2000 is being widely adopted by utilities as a minimum requirement for utility interconnection. This report summarizes work done at the SNL balance-of-systems laboratory to support the development of IEEE 929-2000 and to assist manufacturers in meeting its requirements.

  1. Base drive for paralleled inverter systems

    NASA Technical Reports Server (NTRS)

    Nagano, S. (Inventor)

    1980-01-01

    In a paralleled inverter system, a positive feedback current derived from the total current from all of the modules of the inverter system is applied to the base drive of each of the power transistors of all modules, thereby to provide all modules protection against open or short circuit faults occurring in any of the modules, and force equal current sharing among the modules during turn on of the power transistors.

  2. Automatic load sharing in inverter modules

    NASA Technical Reports Server (NTRS)

    Nagano, S.

    1979-01-01

    Active feedback loads transistor equally with little power loss. Circuit is suitable for balancing modular inverters in spacecraft, computer power supplies, solar-electric power generators, and electric vehicles. Current-balancing circuit senses differences between collector current for power transistor and average value of load currents for all power transistors. Principle is effective not only in fixed duty-cycle inverters but also in converters operating at variable duty cycles.

  3. Inverted liver with suprahepatic, anteriorly displaced gallbladder.

    PubMed

    Hibbs, Harold; Ahmad, Usman

    2010-01-01

    A suprahepatic, anteriorly displaced gallbladder in association with an inverted liver is an extremely rare congenital anomaly. We report the clinical and radiologic findings associated with a 78-year-old woman presenting with shortness of breath, desaturation, hypercapnia and hypoxemia. An abnormal chest radiograph demonstrated right hemi-diaphragmatic elevation consistent with a possible eventration. Subsequent imaging by computed tomography (CT) demonstrated an inverted liver with an anteriorly displaced, suprahepatic gallbladder. PMID:20666167

  4. Work Station For Inverting Solar Cells

    NASA Technical Reports Server (NTRS)

    Feder, H.; Frasch, W.

    1982-01-01

    Final work station along walking-beam conveyor of solar-array assembly line turns each pretabbed solar cell over, depositing it back-side-up onto landing pad, which centers cell without engaging collector surface. Solar cell arrives at inverting work station collector-side-up with two interconnect tabs attached to collector side. Cells are inverted so that second soldering operation takes place in plain view of operator. Inversion protects collector from damage when handled at later stages of assembly.

  5. Are Archean lithospheric keels inverted?

    NASA Astrophysics Data System (ADS)

    Percival, J. A.; Pysklywec, R. N.

    2007-02-01

    Post-tectonic granite "blooms" in many Archean cratons manifest widespread crustal melting that cannot be explained by lithosphere removal, considering the long-term buoyancy of Archean cratonic keels and low mantle geotherms indicated by Archean diamondiferous lithosphere. Rather, heat may have been transferred from the mantle through a process of lithosphere inversion, driven by basal tractive forces acting on gravitationally unstable lithosphere. The top-heavy cell comprises eclogitic lower crust ( ρ = 3500 kg/m 3) lying above depleted mantle lithosphere ( ρ = 3300 kg/m 3), whose aggregate density remained less than that of surrounding asthenosphere ( ρ = 3340 kg/m 3). Parameterized numerical models of the inversion process show a > 40 m.y. pulse of maximum 1060 °C temperatures in the lower crust, sufficient to drive anhydrous melting, when overturned basal lithosphere reaches the Moho. In equilibrating to lower lithosphere conditions, the eclogitic cap may have yielded siliceous melts that infiltrated overlying, previously depleted mantle, producing the high Si/Mg characteristic of some cratonic peridotites. P-T paths calculated for the central part of the inverting cell criss-cross the graphite-diamond boundary, explaining development of large diamond crystals through numerous growth increments. The craton stabilization process follows terminal tectonism by about 50 m.y. as a result of initial cooling, eclogite formation and lithosphere stiffening. Related consequences in the crust include low-pressure regional metamorphism and widespread hydrothermal effects including some gold mineralization. Craton stability is attributed to the high strength of the depleted mantle lithosphere, its rectified density profile, and the presence of refractory compositions at the lithosphere-asthenosphere boundary.

  6. EMPLACEMENT DRIFT INVERT-LOW STEEL EVALUATION

    SciTech Connect

    M. E. Taylor and D. H. Tang

    2000-09-29

    This technical report evaluates and develops options for reducing the amount of steel in the emplacement drift invert. Concepts developed in the ''Invert Configuration and Drip Shield Interface'' were evaluated to determine material properties required for the proposed invert concepts. Project requirements documents prescribe the use of a carbon steel frame for the invert with a granular material of crushed tuff as ballast. The ''Invert Configuration and Drip Shield Interface'' developed three concepts: (1) All-Ballast Invert; (2) Modified Steel Invert with Ballast; and (3) Steel Tie with Ballast Invert. Analysis of the steel frame members, runway beams, and guide beams, for the modified steel invert with ballast, decreased the quantity of steel in the emplacement drift invert, however a substantial steel support frame for the gantry and waste package/pallet assembly is still required. Use of one of the other two concepts appears to be an alternative to the steel frame and each of the concepts uses considerably less steel materials. Analysis of the steel tie with ballast invert shows that the bearing pressure on the ballast under the single steel tie, C 9 x 20, loaded with the waste package/pallet assembly, drip shield, and backfill exceeds the upper bound of the allowable bearing capacity for tuff used in this study. The single tie, C 10 x 20, will also fail for the same loading condition except for the tie length of 4.2 meters and longer. Analysis also shows that with two ties, C 9 or 10 x 20's, the average ballast pressure is less than the allowable bearing capacity. Distributing the waste package/pallet, drip shield, and backfill loads to two steel ties reduces the contact bearing pressure. Modifying the emplacement pallet end beams to a greater width, reducing the tie spacing, and increasing the width of the ties would ensure that the pallet beams are always supported by two steel ties. Further analysis is required to determine compatible tie size and spacing

  7. Reconfigurable multiport EPON repeater

    NASA Astrophysics Data System (ADS)

    Oishi, Masayuki; Inohara, Ryo; Agata, Akira; Horiuchi, Yukio

    2009-11-01

    An extended reach EPON repeater is one of the solutions to effectively expand FTTH service areas. In this paper, we propose a reconfigurable multi-port EPON repeater for effective accommodation of multiple ODNs with a single OLT line card. The proposed repeater, which has multi-ports in both OLT and ODN sides, consists of TRs, BTRs with the CDR function and a reconfigurable electrical matrix switch, can accommodate multiple ODNs to a single OLT line card by controlling the connection of the matrix switch. Although conventional EPON repeaters require full OLT line cards to accommodate subscribers from the initial installation stage, the proposed repeater can dramatically reduce the number of required line cards especially when the number of subscribers is less than a half of the maximum registerable users per OLT. Numerical calculation results show that the extended reach EPON system with the proposed EPON repeater can save 17.5% of the initial installation cost compared with a conventional repeater, and can be less expensive than conventional systems up to the maximum subscribers especially when the percentage of ODNs in lightly-populated areas is higher.

  8. Revisiting the TALE repeat.

    PubMed

    Deng, Dong; Yan, Chuangye; Wu, Jianping; Pan, Xiaojing; Yan, Nieng

    2014-04-01

    Transcription activator-like (TAL) effectors specifically bind to double stranded (ds) DNA through a central domain of tandem repeats. Each TAL effector (TALE) repeat comprises 33-35 amino acids and recognizes one specific DNA base through a highly variable residue at a fixed position in the repeat. Structural studies have revealed the molecular basis of DNA recognition by TALE repeats. Examination of the overall structure reveals that the basic building block of TALE protein, namely a helical hairpin, is one-helix shifted from the previously defined TALE motif. Here we wish to suggest a structure-based re-demarcation of the TALE repeat which starts with the residues that bind to the DNA backbone phosphate and concludes with the base-recognition hyper-variable residue. This new numbering system is consistent with the α-solenoid superfamily to which TALE belongs, and reflects the structural integrity of TAL effectors. In addition, it confers integral number of TALE repeats that matches the number of bound DNA bases. We then present fifteen crystal structures of engineered dHax3 variants in complex with target DNA molecules, which elucidate the structural basis for the recognition of bases adenine (A) and guanine (G) by reported or uncharacterized TALE codes. Finally, we analyzed the sequence-structure correlation of the amino acid residues within a TALE repeat. The structural analyses reported here may advance the mechanistic understanding of TALE proteins and facilitate the design of TALEN with improved affinity and specificity. PMID:24622844

  9. Quantum repeated games revisited

    NASA Astrophysics Data System (ADS)

    Frąckiewicz, Piotr

    2012-03-01

    We present a scheme for playing quantum repeated 2 × 2 games based on Marinatto and Weber’s approach to quantum games. As a potential application, we study the twice repeated Prisoner’s Dilemma game. We show that results not available in the classical game can be obtained when the game is played in the quantum way. Before we present our idea, we comment on the previous scheme of playing quantum repeated games proposed by Iqbal and Toor. We point out the drawbacks that make their results unacceptable.

  10. Addressable inverter matrix for process and device characterization

    NASA Technical Reports Server (NTRS)

    Buehler, M. G.; Sayah, H. R.

    1985-01-01

    The addressable inverter matrix consists of 222 inverters each accessible with the aid of a shift register. The structure has proven useful in characterizing the variability of inverter transfer curves and in diagnosing processing faults. For good 3-micron CMOS bulk inverters investigated, the percent standard deviation of the inverter threshold voltage was less than one percent and the inverter gain (the slope of the inverter transfer curve at the inverter threshold vltage) was less than 3 percent. The average noise margin for the inverters was near 2 volts for a power supply voltage of 5 volts. The specific faults studied included undersize pull-down transistor widths and various open contacts in the matrix.

  11. Addressable inverter matrix for process and device characterization

    NASA Technical Reports Server (NTRS)

    Buehler, M. G.; Sayah, H. R.

    1985-01-01

    The addressable inverter matrix consists of 222 inverters each accessible with the aid of a shift register. The structure has proven useful in characterizing the variability of inverter transfer curves and in diagnosing processing faults. For good 3-micron CMOS bulk inverters investigated in this study, the percent standard deviation of the inverter threshold voltage was less than one percent and the inverter gain (the slope of the inverter transfer curve at the inverter threshold voltage) was less than 3 percent. The average noise margin for the inverters was near 2 volts for a power supply voltage of 5 volts. The specific faults studied included undersize pull-down transistor widths and various open contacts in the matrix.

  12. Recovery from adaptation to facial identity is larger for upright than inverted faces in the human occipito-temporal cortex.

    PubMed

    Mazard, Angelique; Schiltz, Christine; Rossion, Bruno

    2006-01-01

    Human faces look more similar to each other when they are presented upside-down, leading to an increase of error rates and response times during individual face discrimination tasks. Here we used functional magnetic resonance imaging (fMRI) to test the hypothesis that this perceived similarity leads to a lower recovery from identity adaptation for inverted faces than for upright faces in face-sensitive areas of the occipito-temporal cortex. Ten subjects were presented with blocks of upright and inverted faces, with the same face identity repeated consecutively in half of the blocks, and different facial identities repeated in the other blocks. When face stimuli were presented upright, the percent signal change in the bilateral middle fusiform gyrus (MFG) was larger for different faces as compared to same faces, replicating previous observations of a recovery from facial identity adaptation in this region. However, there was no significant recovery from adaptation when different inverted faces were presented. Most interestingly, the difference in activation between upright and inverted faces increased progressively during a block when different facial identities were presented. A similar pattern of activation was found in the left middle fusiform gyrus, but was less clear-cut in bilateral face-sensitive areas of the inferior occipital cortex. These findings show that the differential level of activation to upright and inverted faces in the fusiform gyrus is mainly due to a difference in recovery from adaptation, and they explain the discrepancies in the results reported in previous fMRI studies which compared the processing of upright and inverted faces. The lack of recovery from adaptation for inverted faces in the fusiform gyrus may underlie the face inversion effect (FIE), which takes place during perceptual encoding of individual face representations. PMID:16229867

  13. An SCR inverter for electric vehicles

    NASA Technical Reports Server (NTRS)

    Latos, T.; Bosack, D.; Ehrlich, R.; Jahns, T.; Mezera, J.; Thimmesch, D.

    1980-01-01

    An inverter for an electric vehicle propulsion application has been designed and constructed to excite a polyphase induction motor from a fixed propulsion battery source. The inverter, rated at 35kW peak power, is fully regenerative and permits vehicle operation in both the forward and reverse directions. Thyristors are employed as the power switching devices arranged in a dc bus commutated topology. This paper describes the major role the controller plays in generating the motor excitation voltage and frequency to deliver performance similar to dc systems. Motoring efficiency test data for the controller are presented. It is concluded that an SCR inverter in conjunction with an ac induction motor is a viable alternative to present dc vehicle propulsion systems on the basis of performance and size criteria.

  14. A diagonally inverted LU implicit multigrid scheme

    NASA Technical Reports Server (NTRS)

    Yokota, Jeffrey W.; Caughey, David A.; Chima, Rodrick V.

    1988-01-01

    A new Diagonally Inverted LU Implicit scheme is developed within the framework of the multigrid method for the 3-D unsteady Euler equations. The matrix systems that are to be inverted in the LU scheme are treated by local diagonalizing transformations that decouple them into systems of scalar equations. Unlike the Diagonalized ADI method, the time accuracy of the LU scheme is not reduced since the diagonalization procedure does not destroy time conservation. Even more importantly, this diagonalization significantly reduces the computational effort required to solve the LU approximation and therefore transforms it into a more efficient method of numerically solving the 3-D Euler equations.

  15. High voltage series resonant inverter ion engine screen supply. [SCR series resonant inverter for space applications

    NASA Technical Reports Server (NTRS)

    Biess, J. J.; Inouye, L. Y.; Shank, J. H.

    1974-01-01

    A high-voltage, high-power LC series resonant inverter using SCRs has been developed for an Ion Engine Power Processor. The inverter operates within 200-400Vdc with a maximum output power of 2.5kW. The inverter control logic, the screen supply electrical and mechanical characteristics, the efficiency and losses in power components, regulation on the dual feedback principle, the SCR waveforms and the component weight are analyzed. Efficiency of 90.5% and weight density of 4.1kg/kW are obtained.

  16. Inverter Load Rejection Over-Voltage Testing: SolarCity CRADA Task 1a Final Report

    SciTech Connect

    Nelson, A.; Hoke, A.; Chakraborty, S.; Chebahtah, J.; Wang, T.; Zimmerly, B.

    2015-02-01

    Various interconnection challenges exist when connecting distributed PV into the electrical distribution grid in terms of safety, reliability, and stability of electric power systems. One of the urgent areas for additional research - as identified by inverter manufacturers, installers, and utilities - is the potential for transient over-voltage from PV inverters. In one stage of a cooperative tests were repeated a total of seven times. The maximum over-voltage measured in any test did not exceed 200% of nominal, and typical over-voltage levels were significantly lower. The total voltage duration and the maximum continuous time above each threshold are presented here, as well as the time to disconnect for each test. Finally, we present a brief investigation into the effect of DC input voltage as well as a series of no-load tests. This report describes testing conducted at NREL to determine the duration and magnitude of transient over-voltages created by several commercial PV inverters during load-rejection conditions. For this work, a test plan that is currently under development by the Forum on Inverter Grid Integration Issues (FIGII) has been implemented in a custom test setup at NREL. Through a cooperative research and development agreement, NREL is working with SolarCity to address two specific types of transient overvoltage: load rejection overvoltage (LRO) and ground fault overvoltage (GFO). Additional partners in this effort include the Hawaiian Electric Companies, Northern Plains Power Technologies, and the Electric Power Research Institute.

  17. Inverted Meckel’s diverticulum preoperatively diagnosed using double-balloon enteroscopy

    PubMed Central

    Takagaki, Kosuke; Osawa, Satoshi; Ito, Tatsuhiro; Iwaizumi, Moriya; Hamaya, Yasushi; Tsukui, Hiroe; Furuta, Takahisa; Wada, Hidetoshi; Baba, Satoshi; Sugimoto, Ken

    2016-01-01

    An inverted Meckel’s diverticulum is a rare gastrointestinal congenital anomaly that is difficult to diagnose prior to surgery and presents with anemia, abdominal pain, or intussusception. Here, we report the case of 57-year-old men with an inverted Meckel’s diverticulum, who was preoperatively diagnosed using double-balloon enteroscopy. He had repeatedly experienced epigastric pain for 2 mo. Ultrasonography and computed tomography showed intestinal wall thickening in the pelvis. Double-balloon enteroscopy via the anal route was performed for further examination, which demonstrated an approximately 8-cm, sausage-shaped, submucosal tumor located approximately 80 cm proximal to the ileocecal valve. A small depressed erosion was observed at the tip of this lesion. Forceps biopsy revealed heterotopic gastric mucosa. Thus, the patient was diagnosed with an inverted Meckel’s diverticulum, and single-incision laparoscopic surgery was performed. This case suggests that an inverted Meckel’s diverticulum should be considered as a differential diagnosis for a submucosal tumor in the ileum. Balloon-assisted enteroscopy with forceps biopsy facilitate a precise diagnosis of this condition. PMID:27158212

  18. Dynamic maneuvers with a mobile inverted pendulum

    NASA Astrophysics Data System (ADS)

    Pogue, Edward

    A mobile inverted pendulum (MIP) type robot was constructed to test the feasibility of performing high speed, dynamic maneuvers. Techniques were developed for line following and to achieve high speed motion with a MIP. The results indicate that the speeds necessary for the maneuver can be achieved, and the groundwork is laid for further experimentation.

  19. Two-Stage Series-Resonant Inverter

    NASA Technical Reports Server (NTRS)

    Stuart, Thomas A.

    1994-01-01

    Two-stage inverter includes variable-frequency, voltage-regulating first stage and fixed-frequency second stage. Lightweight circuit provides regulated power and is invulnerable to output short circuits. Does not require large capacitor across ac bus, like parallel resonant designs. Particularly suitable for use in ac-power-distribution system of aircraft.

  20. Inverter Matrix for the Clementine Mission

    NASA Technical Reports Server (NTRS)

    Buehler, M. G.; Blaes, B. R.; Tardio, G.; Soli, G. A.

    1994-01-01

    An inverter matrix test circuit was designed for the Clementine space mission and is built into the RRELAX (Radiation and Reliability Assurance Experiment). The objective is to develop a circuit that will allow the evaluation of the CMOS FETs using a lean data set in the noisy spacecraft environment.

  1. Pulse width modulation inverter with battery charger

    NASA Technical Reports Server (NTRS)

    Slicker, James M. (Inventor)

    1985-01-01

    An inverter is connected between a source of DC power and a three-phase AC induction motor, and a microprocessor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .theta., where .theta. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands for electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a flyback DC-DC converter circuit for recharging the battery.

  2. A Prefix Trie Index for Inverted Files.

    ERIC Educational Resources Information Center

    Nelson, Michael J.

    1997-01-01

    Applies a prefix trie index, or trie hashing, to the problem of providing fast search times, fast load times, and fast update properties in a bibliographic or full-text retrieval system with inverted files. Statistics are given for a test database consisting of an online catalog at the University of Western Ontario. (Author/LRW)

  3. Pulse width modulation inverter with battery charger

    DOEpatents

    Slicker, James M.

    1985-01-01

    An inverter is connected between a source of DC power and a three-phase AC induction motor, and a microprocessor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .theta., where .theta. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands for electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a "flyback" DC-DC converter circuit for recharging the battery.

  4. The Internet and the Inverted Classroom.

    ERIC Educational Resources Information Center

    Lage, Maureen J.; Platt, Glenn

    2000-01-01

    Describes a Web site that is for an undergraduate principles of microeconomics course and a main component of "The Inverted Classroom" in which lectures take place outside of class. Explains that the Web site is divided into four sections: (1) the classroom; (2) the desk; (3) the coffee shop; and (4) the library. (CMK)

  5. View of Inverted Siphon crossing Hot Water (or White) Canyon. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of Inverted Siphon crossing Hot Water (or White) Canyon. Looking northeast - Childs-Irving Hydroelectric Project, Irving System, Inverted Siphon, Forest Service Road 708/502, Camp Verde, Yavapai County, AZ

  6. The Pentapeptide Repeat Proteins

    SciTech Connect

    Vetting,M.; Hegde, S.; Fajardo, J.; Fiser, A.; Roderick, S.; Takiff, H.; Blanchard, J.

    2006-01-01

    The Pentapeptide Repeat Protein (PRP) family has over 500 members in the prokaryotic and eukaryotic kingdoms. These proteins are composed of, or contain domains composed of, tandemly repeated amino acid sequences with a consensus sequence of [S, T,A, V][D, N][L, F]-[S, T,R][G]. The biochemical function of the vast majority of PRP family members is unknown. The three-dimensional structure of the first member of the PRP family was determined for the fluoroquinolone resistance protein (MfpA) from Mycobacterium tuberculosis. The structure revealed that the pentapeptide repeats encode the folding of a novel right-handed quadrilateral {beta}-helix. MfpA binds to DNA gyrase and inhibits its activity. The rod-shaped, dimeric protein exhibits remarkable size, shape and electrostatic similarity to DNA.

  7. Honesty through repeated interactions.

    PubMed

    Rich, Patricia; Zollman, Kevin J S

    2016-04-21

    In the study of signaling, it is well known that the cost of deception is an essential element for stable honest signaling in nature. In this paper, we show how costs for deception can arise endogenously from repeated interactions between individuals. Utilizing the Sir Philip Sidney game as an illustrative case, we show that repeated interactions can sustain honesty with no observable signal costs, even when deception cannot be directly observed. We provide a number of potential experimental tests for this theory which distinguish it from the available alternatives. PMID:26869213

  8. Miniature inverted-repeat transposable element identification and genetic marker development in Agrostis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Creeping bentgrass (Agrostis stolonifera L.) is an important species to the turfgrass industry because of its adaptation for use in high quality turf stands such as golf course putting greens, tees, and fairways. A. stolonifera is a highly outcrossing allotetraploid making genetic marker developmen...

  9. DC-to-AC inverter ratio failure detector

    NASA Technical Reports Server (NTRS)

    Ebersole, T. J.; Andrews, R. E.

    1975-01-01

    Failure detection technique is based upon input-output ratios, which is independent of inverter loading. Since inverter has fixed relationship between V-in/V-out and I-in/I-out, failure detection criteria are based on this ratio, which is simply inverter transformer turns ratio, K, equal to primary turns divided by secondary turns.

  10. Efficient/reliable dc-to-dc inverter circuit

    NASA Technical Reports Server (NTRS)

    Pasciutti, E. R.

    1970-01-01

    Feedback loop, which contains an inductor in series with a saturable reactor, is added to a standard inverter circuit to permit the inverter power transistors to be switched in a controlled and efficient manner. This inverter is applicable where the power source has either high or low impedance properties.

  11. Mobile Inverted Constructivism: Education of Interaction Technology in Social Media

    ERIC Educational Resources Information Center

    Chai, Jia-Xiang; Fan, Kuo-Kuang

    2016-01-01

    The combination of social media and invert teaching is a new path to inverting interation technology education and reconstructing the curriculum of context. In this paper, based on the theory of constructivism learning, a model named Mobile Inverted Constructivism (MIC) is provided. Moreover, in view of the functional quality of social media in…

  12. Triggering of repeated earthquakes

    NASA Astrophysics Data System (ADS)

    Sobolev, G. A.; Zakrzhevskaya, N. A.; Sobolev, D. G.

    2016-03-01

    Based on the analysis of the world's earthquakes with magnitudes M ≥ 6.5 for 1960-2013, it is shown that they cause global-scale coherent seismic oscillations which most distinctly manifest themselves in the period interval of 4-6 min during 1-3 days after the event. After these earthquakes, a repeated shock has an increased probability to occur in different seismically active regions located as far away as a few thousand km from the previous event, i.e., a remote interaction of seismic events takes place. The number of the repeated shocks N( t) decreases with time, which characterizes the memory of the lithosphere about the impact that has occurred. The time decay N( t) can be approximated by the linear, exponential, and powerlaw dependences. No distinct correlation between the spatial locations of the initial and repeated earthquakes is revealed. The probable triggering mechanisms of the remote interaction between the earthquakes are discussed. Surface seismic waves traveling several times around the Earth's, coherent oscillations, and global source are the most preferable candidates. This may lead to the accumulation and coalescence of ruptures in the highly stressed or weakened domains of a seismically active region, which increases the probability of a repeated earthquake.

  13. Repeated Causal Decision Making

    ERIC Educational Resources Information Center

    Hagmayer, York; Meder, Bjorn

    2013-01-01

    Many of our decisions refer to actions that have a causal impact on the external environment. Such actions may not only allow for the mere learning of expected values or utilities but also for acquiring knowledge about the causal structure of our world. We used a repeated decision-making paradigm to examine what kind of knowledge people acquire in…

  14. Bidirectional Manchester repeater

    NASA Technical Reports Server (NTRS)

    Ferguson, J.

    1980-01-01

    Bidirectional Manchester repeater is inserted at periodic intervals along single bidirectional twisted pair transmission line to detect, amplify, and transmit bidirectional Manchester 11 code signals. Requiring only 18 TTL 7400 series IC's, some line receivers and drivers, and handful of passive components, circuit is simple and relatively inexpensive to build.

  15. Electronic Document Management Using Inverted Files System

    NASA Astrophysics Data System (ADS)

    Suhartono, Derwin; Setiawan, Erwin; Irwanto, Djon

    2014-03-01

    The amount of documents increases so fast. Those documents exist not only in a paper based but also in an electronic based. It can be seen from the data sample taken by the SpringerLink publisher in 2010, which showed an increase in the number of digital document collections from 2003 to mid of 2010. Then, how to manage them well becomes an important need. This paper describes a new method in managing documents called as inverted files system. Related with the electronic based document, the inverted files system will closely used in term of its usage to document so that it can be searched over the Internet using the Search Engine. It can improve document search mechanism and document save mechanism.

  16. On the uncontrollable damped triple inverted pendulum

    NASA Astrophysics Data System (ADS)

    Su, H.; Woodham, C. A.

    2003-02-01

    In this paper, the controllability of the damped triple inverted pendulum is investigated. The work is concerned with the form of the cancelling pole and zero which appear in the transfer functions of an uncontrollable system, and follows on from earlier work on the damped double inverted pendulum. The investigation considers first the cases where only one of the three arm frictions is non-zero, and then explores the cases when two of the three arm frictions are non-zero. Due to the complexity of this problem, and the difficulties with the symbolic manipulation software, exploratory numerical investigations have been carried out to facilitate the symbolic investigations, all of which are reported here.

  17. Micro-inverter solar panel mounting

    DOEpatents

    Morris, John; Gilchrist, Phillip Charles

    2016-02-02

    Processes, systems, devices, and articles of manufacture are provided. Each may include adapting micro-inverters initially configured for frame-mounting to mounting on a frameless solar panel. This securement may include using an adaptive clamp or several adaptive clamps secured to a micro-inverter or its components, and using compressive forces applied directly to the solar panel to secure the adaptive clamp and the components to the solar panel. The clamps can also include compressive spacers and safeties for managing the compressive forces exerted on the solar panels. Friction zones may also be used for managing slipping between the clamp and the solar panel during or after installation. Adjustments to the clamps may be carried out through various means and by changing the physical size of the clamps themselves.

  18. The Invertible Double of Elliptic Operators

    NASA Astrophysics Data System (ADS)

    Booss-Bavnbek, Bernhelm; Lesch, Matthias

    2009-02-01

    First, we review the Dirac operator folklore about basic analytic and geometrical properties of operators of Dirac type on compact manifolds with smooth boundary and on closed partitioned manifolds and show how these properties depend on the construction of a canonical invertible double and are related to the concept of the Calderón projection. Then we summarize a recent construction of a canonical invertible double for general first order elliptic differential operators over smooth compact manifolds with boundary. We derive a natural formula for the Calderón projection which yields a generalization of the famous Cobordism Theorem. We provide a list of assumptions to obtain a continuous variation of the Calderón projection under smooth variation of the coefficients. That yields various new spectral flow theorems. Finally, we sketch a research program for confining, respectively closing, the last remaining gaps between the geometric Dirac operator type situation and the general linear elliptic case.

  19. Maskless inverted pyramid texturization of silicon.

    PubMed

    Wang, Yan; Yang, Lixia; Liu, Yaoping; Mei, Zengxia; Chen, Wei; Li, Junqiang; Liang, Huili; Kuznetsov, Andrej; Xiaolong, Du

    2015-01-01

    We discovered a technical solution of such outstanding importance that it can trigger new approaches in silicon wet etching processing and, in particular, photovoltaic cell manufacturing. The so called inverted pyramid arrays, outperforming conventional pyramid textures and black silicon because of their superior light-trapping and structure characteristics, can currently only be achieved using more complex techniques involving lithography, laser processing, etc. Importantly, our data demonstrate a feasibility of inverted pyramidal texturization of silicon by maskless Cu-nanoparticles assisted etching in Cu(NO3)2 / HF / H2O2 / H2O solutions and as such may have significant impacts on communities of fellow researchers and industrialists. PMID:26035520

  20. Invertible linear transformations and the Lie algebras

    NASA Astrophysics Data System (ADS)

    Zhang, Yufeng; Tam, Honwah; Guo, Fukui

    2008-07-01

    With the help of invertible linear transformations and the known Lie algebras, a way to generate new Lie algebras is given. These Lie algebras obtained have a common feature, i.e. integrable couplings of solitary hierarchies could be obtained by using them, specially, the Hamiltonian structures of them could be worked out. Some ways to construct the loop algebras of the Lie algebras are presented. It follows that some various loop algebras are given. In addition, a few new Lie algebras are explicitly constructed in terms of the classification of Lie algebras proposed by Ma Wen-Xiu, which are bases for obtaining new Lie algebras by using invertible linear transformations. Finally, some solutions of a (2 + 1)-dimensional partial-differential equation hierarchy are obtained, whose Hamiltonian form-expressions are manifested by using the quadratic-form identity.

  1. Maskless inverted pyramid texturization of silicon

    PubMed Central

    Wang, Yan; Yang, Lixia; Liu, Yaoping; Mei, Zengxia; Chen, Wei; Li, Junqiang; Liang, Huili; Kuznetsov, Andrej; Xiaolong, Du

    2015-01-01

    We discovered a technical solution of such outstanding importance that it can trigger new approaches in silicon wet etching processing and, in particular, photovoltaic cell manufacturing. The so called inverted pyramid arrays, outperforming conventional pyramid textures and black silicon because of their superior light-trapping and structure characteristics, can currently only be achieved using more complex techniques involving lithography, laser processing, etc. Importantly, our data demonstrate a feasibility of inverted pyramidal texturization of silicon by maskless Cu-nanoparticles assisted etching in Cu(NO3)2 / HF / H2O2 / H2O solutions and as such may have significant impacts on communities of fellow researchers and industrialists. PMID:26035520

  2. Intelligent Control of an Inverted Pendulum

    NASA Astrophysics Data System (ADS)

    Rekdalsbakken, Webjorn

    An inverted pendulum represents an unstable system which is excellent for demonstrating the use of feedback control with different kinds of control strategies. In this work state feedback of the inverted pendulum is examined. First a pole placement algorithm is explored. After that artificial intelligence (AI) methods are investigated to better cope with the nonlinearities of the physical model. The technique used is based on a hybrid system combining a neural network (NN) with a genetic algorithm (GA). The NN controller is trained by the GA against the behaviour of the physical model. The results of the training process show that the chromosome population tends to station at a suboptimal level, and that changes in the environmental parameters have to take place to reach a new optimal level. By systematically changing these parameters the NN controller will gradually adapt to the pendulum behaviour.

  3. Inverter testing at Sandia National Laboratories

    SciTech Connect

    Ginn, J.W.; Bonn, R.H.; Sittler, G.

    1997-04-01

    Inverters are key building blocks of photovoltaic (PV) systems that produce ac power. The balance of systems (BOS) portion of a PV system can account for up to 50% of the system cost, and its reliable operation is essential for a successful PV system. As part of its BOS program, Sandia National Laboratories (SNL) maintains a laboratory wherein accurate electrical measurements of power systems can be made under a variety of conditions. This paper outlines the work that is done in that laboratory.

  4. Coaxial inverted geometry transistor having buried emitter

    NASA Technical Reports Server (NTRS)

    Hruby, R. J.; Cress, S. B.; Dunn, W. R. (Inventor)

    1973-01-01

    The invention relates to an inverted geometry transistor wherein the emitter is buried within the substrate. The transistor can be fabricated as a part of a monolithic integrated circuit and is particularly suited for use in applications where it is desired to employ low actuating voltages. The transistor may employ the same doping levels in the collector and emitter, so these connections can be reversed.

  5. Inverted colloidal quantum dot solar cells.

    PubMed

    Kim, Gi-Hwan; Walker, Bright; Kim, Hak-Beom; Kim, Jin Young; Sargent, Edward H; Park, Jongnam; Kim, Jin Young

    2014-05-28

    An inverted architecture of quantum dot solar cells is demonstrated by introducing a novel ZnO method on top of the PbS CQD film. Improvements in device characteristics stem from constructive optical interference from the ZnO layer that enhances absorption in the PbS CQD layer. Outstanding diode characteristics arising from a superior PbS/ZnO junction provide a further electronic advantage. PMID:24677118

  6. Rhenium Disulfide Depletion-Load Inverter

    NASA Astrophysics Data System (ADS)

    McClellan, Connor; Corbet, Chris; Rai, Amritesh; Movva, Hema C. P.; Tutuc, Emanuel; Banerjee, Sanjay K.

    2015-03-01

    Many semiconducting Transition Metal Dichalcogenide (TMD) materials have been effectively used to create Field-Effect Transistor (FET) devices but have yet to be used in logic designs. We constructed a depletion-load voltage inverter using ultrathin layers of Rhenium Disulfide (ReS2) as the semiconducting channel. This ReS2 inverter was fabricated on a single micromechanically-exfoliated flake of ReS2. Electron beam lithography and physical vapor deposition were used to construct Cr/Au electrical contacts, an Alumina top-gate dielectric, and metal top-gate electrodes. By using both low (Aluminum) and high (Palladium) work-function metals as two separate top-gates on a single ReS2 flake, we create a dual-gated depletion mode (D-mode) and enhancement mode (E-mode) FETs in series. Both FETs displayed current saturation in the output characteristics as a result of the FET ``pinch-off'' mechanism and On/Off current ratios of 105. Field-effect mobilities of 23 and 17 cm2V-1s-1 and subthreshold swings of 97 and 551 mV/decade were calculated for the E-mode and D-mode FETs, respectively. With a supply voltage of 1V, at low/negative input voltages the inverter output was at a high logic state of 900 mV. Conversely with high/positive input voltages, the inverter output was at a low logic state of 500 mV. The inversion of the input signal demonstrates the potential for using ReS2 in future integrated circuit designs and the versatility of depletion-load logic devices for TMD research. NRI SWAN Center and ARL STTR Program.

  7. FET commutated current-FED inverter

    NASA Technical Reports Server (NTRS)

    Rippel, Wally E. (Inventor); Edwards, Dean B. (Inventor)

    1983-01-01

    A shunt switch comprised of a field-effect transistor (Q.sub.1) is employed to commutate a current-fed inverter (10) using thyristors (SCR1, SCR2) or bijunction transistors (Q.sub.2, Q.sub.3) in a full bridge (1, 2, 3, 4) or half bridge (5, 6) and transformer (T.sub.1) configuration. In the case of thyristors, a tapped inverter (12) is employed to couple the inverter to a dc source to back bias the thyristors during commutation. Alternatively, a commutation power supply (20) may be employed for that purpse. Diodes (D.sub.1, D.sub.2) in series with some voltage dropping element (resistor R.sub.12 or resistors R.sub.1, R.sub.2 or Zener diodes D.sub.4, D.sub.5) are connected in parallel with the thyristors in the half bridge and transformer configuration to assure sharing the back bias voltage. A clamp circuit comprised of a winding (18) negatively coupled to the inductor and a diode (D.sub.3) return stored energy from the inductor to the power supply for efficient operation with buck or boost mode.

  8. The simian varicella virus genome contains an invertible 665 base pair terminal element that is absent in the varicella zoster virus genome

    PubMed Central

    Mahalingam, Ravi; Gray, Wayne L.

    2007-01-01

    Simian varicella virus (SVV) causes chickenpox in monkeys, establishes latency, and reactivates to produce zoster thus providing a model to study human varicella zoster virus (VZV) infection. Sequence analysis of a recombinant cosmid clone containing the left end of the SVV genome revealed a 665 base pair (bp) segment that is absent in VZV DNA. This segment inverts and contains 507 bp of unique sequences flanked on either side by 79 bp inverted repeats, making the SVV genome to be 124,785 bp in size. Part of the inverted repeat sequence (64 bp) is also present at the junction of the long and short segments of the SVV genome. The terminal DNA sequences are conserved among different SVV isolates and present in tissues from infected monkeys. The terminal region is transcriptionally active and is also present in the genomes of other animal varicelloviruses, but absent in the VZV genome. PMID:17555785

  9. Accumulate repeat accumulate codes

    NASA Technical Reports Server (NTRS)

    Abbasfar, Aliazam; Divsalar, Dariush; Yao, Kung

    2004-01-01

    In this paper we propose an innovative channel coding scheme called 'Accumulate Repeat Accumulate codes' (ARA). This class of codes can be viewed as serial turbo-like codes, or as a subclass of Low Density Parity Check (LDPC) codes, thus belief propagation can be used for iterative decoding of ARA codes on a graph. The structure of encoder for this class can be viewed as precoded Repeat Accumulate (RA) code or as precoded Irregular Repeat Accumulate (IRA) code, where simply an accumulator is chosen as a precoder. Thus ARA codes have simple, and very fast encoder structure when they representing LDPC codes. Based on density evolution for LDPC codes through some examples for ARA codes, we show that for maximum variable node degree 5 a minimum bit SNR as low as 0.08 dB from channel capacity for rate 1/2 can be achieved as the block size goes to infinity. Thus based on fixed low maximum variable node degree, its threshold outperforms not only the RA and IRA codes but also the best known LDPC codes with the dame maximum node degree. Furthermore by puncturing the accumulators any desired high rate codes close to code rate 1 can be obtained with thresholds that stay close to the channel capacity thresholds uniformly. Iterative decoding simulation results are provided. The ARA codes also have projected graph or protograph representation that allows for high speed decoder implementation.

  10. Duct Leakage Repeatability Testing

    SciTech Connect

    Walker, Iain; Sherman, Max

    2014-01-01

    Duct leakage often needs to be measured to demonstrate compliance with requirements or to determine energy or Indoor Air Quality (IAQ) impacts. Testing is often done using standards such as ASTM E1554 (ASTM 2013) or California Title 24 (California Energy Commission 2013 & 2013b), but there are several choices of methods available within the accepted standards. Determining which method to use or not use requires an evaluation of those methods in the context of the particular needs. Three factors that are important considerations are the cost of the measurement, the accuracy of the measurement and the repeatability of the measurement. The purpose of this report is to evaluate the repeatability of the three most significant measurement techniques using data from the literature and recently obtained field data. We will also briefly discuss the first two factors. The main question to be answered by this study is to determine if differences in the repeatability of these tests methods is sufficient to indicate that any of these methods is so poor that it should be excluded from consideration as an allowed procedure in codes and standards.

  11. High Power Factor Control Regulating Inverter Output Power in IPM Motor Driven by Inverter System without Electrolytic Capacitor

    NASA Astrophysics Data System (ADS)

    Inazuma, Kazuya; Ohishi, Kiyoshi; Haga, Hitoshi; Sazawa, Mataki; Kondo, Seiji

    This paper presents a new high power factor control method for a single-to-three-phase power converter without an electrolytic capacitor. The circuit used in the method consists of a single-phase rectifier, a small film capacitor at DC-link, a voltage-source three-phase inverter, and an IPM motor. The inverter regulates both the velocity of the IPM motor and input current waveform. In order to obtain a power factor of unity, we propose a new control method that regulates the inverter output power. The inverter output power controller is placed between the speed controller and the q-axis current controller. The inverter power is regulated by a PI and repetitive controller. When repetitive control is applied to the inverter power controller, the phase delay of the inverter power controller is quite small. The superior performance of the proposed method is demonstrated by experimental results.

  12. ``Spin inverter'' as building block of All Spin Logic devices

    NASA Astrophysics Data System (ADS)

    Sarkar, Angik; Srinivasan, Srikant; Datta, Supriyo

    2012-02-01

    All-spin logic (ASL) represents a new approach to information processing where the roles of charges and capacitors in charge based transistors are played by spins and magnets, without the need for repeated spin-charge conversion. In our past work, we have presented numerical simulations based on a coupled spin transport and Landau Lifshitz Gilbert model showing that ring oscillators and logic circuits with intrinsic directionality [IEEE Trans. Magn. 47,10, 4026, 2011; Proc. IEDM, 2011)] can be implemented by manipulation of spins in magnetic nanostructures. The aim of this talk is (1) to identify a basic ASL unit that can be interconnected to build up spin circuits analogous to the way transistors are interconnected to build conventional circuits and (2) to present a compact model for this basic unit that can be used to design and analyze large scale spin circuits. We will show that this basic ASL unit is a one-magnet ``spin inverter'' with gain that can be cascaded to accomplish a spin circuit implementation of almost any logic functionality

  13. Inverted (hobnail) high-grade prostatic intraepithelial neoplasia and invasive inverted pattern

    PubMed Central

    ÖZNUR, MELTEM; KOCA, SEVIM BAYKAL; YILDIZ, PELIN; BAHADIR, BURAK; BEHZATOĞLU, KEMAL

    2015-01-01

    High-grade prostatic intraepithelial neoplasia (HGPIN) is considered to be an important precursor for prostatic adenocarcinoma. The present study aimed to investigate the histological features of the uncommon inverted (hobnail) pattern of HGPIN in transrectal ultrasonographic (TRUS) prostatic needle biopsies from 13 cases. These 13 diagnosed cases of inverted HGPIN were identified out of a total of 2,034 TRUS biopsies (0.63%), obtained from patients suspected to have prostate cancer. The hobnail pattern is comprised of secretory cell nuclei, which are histologically localized at the luminal surface of the prostate gland, rather than the periphery, and exhibit reverse polarity. Histological examinations were performed and the results demonstrated that 5 of the 13 cases exhibited pure inverted histology, while HGPIN was observed to be histologically associated with other patterns in the remaining 8 patients. In addition, an association with adenocarcinoma was identified in 7 of the 13 cases. All 7 carcinomas accompanied by inverted HGPIN were conventional acinar adenocarcinoma cases; of note, for these 7 cases, the Gleason score was 7 for each. One acinar adenocarcinoma case accompanying inverted HGPIN demonstrated hobnail characteristics in large areas of the invasive component. It was observed that nuclei were proliferated in the invasive cribriform glands, which was comparable to that of inverted HGPIN, and were located on the cytoplasmic luminal surface; a similar morphology was also observed in individual glands. In conclusion, the results of the present study suggested that the hobnail HGPIN pattern may be of diagnostic importance due to its high association with adenocarcinoma and the high Gleason scores in the accompanying carcinomas. PMID:26622858

  14. Structure of a Thyroid Hormone Receptor DNA-Binding Domain Homodimer Bound to an Inverted Palindrome DNA Response Element

    SciTech Connect

    Chen, Yi; Young, Matthew A.

    2010-10-22

    Thyroid hormone receptor (TR), as a member of the nuclear hormone receptor family, can recognize and bind different classes of DNA response element targets as either a monomer, a homooligomer, or a heterooligomer. We report here the first crystal structure of a homodimer TR DNA-binding domain (DBD) in complex with an inverted repeat class of thyroid response element (TRE). The structure shows a nearly symmetric structure of the TR DBD assembled on the F2 TRE where the base recognition contacts in the homodimer DNA complex are conserved relative to the previously published structure of a TR-9-cis-retinoic acid receptor heterodimer DNA complex. The new structure also reveals that the T-box region of the DBD can function as a structural hinge that enables a large degree of flexibility in the position of the C-terminal extension helix that connects the DBD to the ligand-binding domain. Although the isolated TR DBDs exist as monomers in solution, we have measured highly cooperative binding of the two TR DBD subunits onto the inverted repeat DNA sequence. This suggests that elements of the DBD can influence the specific TR oligomerization at target genes, and it is not just interactions between the ligand-binding domains that are responsible for TR oligomerization at target genes. Mutational analysis shows that intersubunit contacts at the DBD C terminus account for some, but not all, of the cooperative homodimer TR binding to the inverted repeat class TRE.

  15. Influence of the inverter characteristics on the iron losses in PWM inverter fed induction motors

    SciTech Connect

    Boglietti, A.; Ferraris, P.; Lazzari, M.; Pastorelli, M.

    1995-12-31

    In this paper the authors deal with the effects of the inverter characteristics on the iron losses increment in induction motors fed by PWM controlled converters. Laboratory tests based on no-load input power measurement were carried out and in order to avoid the influence of mechanical losses and rotor copper losses, difficult to be measured or computed, a special test bench with an unconventional test device was employed. In particular the influence of the following inverter parameters are considered: modulation index; modulation waveform; switching frequency. Complete experimental results are presented and discussed.

  16. Semi-transparent inverted organic solar cells

    NASA Astrophysics Data System (ADS)

    Schmidt, H.; Winkler, T.; Tilgner, M.; Flügge, H.; Schmale, S.; Bülow, T.; Meyer, J.; Johannes, H.-H.; Riedl, T.; Kowalsky, W.

    2009-08-01

    We will present efficient semi-transparent bulk-heterojunction [regioregular of poly(3-hexylthiophene): (6,6)-phenyl C61 butyric acid methyl ester] solar cells with an inverted device architecture. Highly transparent ZnO and TiO2 films prepared by Atomic Layer Deposition are used as cathode interlayers on top of ITO. The topanode consists of a RF-sputtered ITO layer. To avoid damage due to the plasma deposition of this layer, a sputtering buffer layer of MoO3 is used as protection. This concept allows for devices with a transmissivity higher than 60 % for wavelengths 650 nm. The thickness of the MoO3 buffer has been varied in order to study its effect on the electrical properties of the solar cell and its ability to prevent possible damage to the organic active layers upon ITO deposition. Without this buffer or for thin buffers it has been found that device performance is very poor concerning the leakage current, the fill factor, the short circuit current and the power conversion efficiencies. As a reference inverted solar cells with a metal electrode (Al) instead of the ITO-top contact are used. The variation between the PCE of top versus conventional illumination of the semi-transparent cells was also examined and will be interpreted in view of the results of the optical simulation of the dielectric device stack with and without reflection top electrode. Power conversion efficiencies of 2-3 % for the opaque inverted solar cells and 1.5-2.5 % for the semi-transparent devices were obtained under an AM1.5G illumination.

  17. Duct Leakage Repeatability Testing

    SciTech Connect

    Walker, Iain; Sherman, Max

    2014-08-01

    The purpose of this report is to evaluate the repeatability of the three most significant measurement techniques for duct leakage using data from the literature and recently obtained field data. We will also briefly discuss the first two factors. The main question to be answered by this study is to determine if differences in the repeatability of these tests methods is sufficient to indicate that any of these methods is so poor that it should be excluded from consideration as an allowed procedure in codes and standards. The three duct leak measurement methods assessed in this report are the two duct pressurization methods that are commonly used by many practitioners and the DeltaQ technique. These are methods B, C and A, respectively of the ASTM E1554 standard. Although it would be useful to evaluate other duct leak test methods, this study focused on those test methods that are commonly used and are required in various test standards, such as BPI (2010), RESNET (2014), ASHRAE 62.2 (2013), California Title 24 (CEC 2012), DOE Weatherization and many other energy efficiency programs.

  18. Repeated measures with zeros.

    PubMed

    Berk, K N; Lachenbruch, P A

    2002-08-01

    Consider repeated measures data with many zeros. For the case with one grouping factor and one repeated measure, we examine several models, assuming that the nonzero data are roughly lognormal. One of the simplest approaches is to model the zeros as left-censored observations from the lognormal distribution. A random effect is assumed for subjects. The censored model makes a strong assumption about the relationship between the zeros and the nonzero values. To check on this, you can instead assume that some of the zeros are 'true' zeros and model them as Bernoulli. Then the other values are modeled with a censored lognormal. A logistic model is used for the Bernoulli p, the probability of a true nonzero. The fit of the pure left-censored lognormal can be assessed by testing the hypothesis that p is 1, as described by Moulton and Halsey. The model can also be simplified by omitting the censoring, leaving a logistic model for the zeros and a lognormal model for the nonzero values. This is approximately equivalent to modeling the zero and nonzero values separately, a two-part model. In contrast to the censored model, this model assumes only a slight relationship (a covariance component) between the occurrence of zeros and the size of the nonzero values. The models are compared in terms of an example with data from children's private speech. PMID:12197298

  19. Volunteer Losing Balance Wearing Inverted Glasses

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Brad McLain for the Space Biology Museum Network puts a volunteer back on balance as he tries to adjust to a world inverted by a special pair of glasses. This helps illustrate how dependent the human vestibular system is on visual cues. A volunteer is The activity was part of the Space Research and You education event held by NASA's Office of Biological and Physical Research on June 25, 2002, in Arlington, VA, to highlight the research that will be conducted on STS-107.

  20. Novel multilevel inverter carrier-based PWM method

    SciTech Connect

    Tolbert, L.M.; Habetler, T.G.

    1999-10-01

    The advent of the transformerless multilevel inverter topology has brought forth various pulsewidth modulation (PWM) schemes as a means to control the switching of the active devices in each of the multiple voltage levels in the inverter. An analysis of how existing multilevel carrier-based PWM affects switch utilization for the different levels of a diode-clamped inverter is conducted. Two novel carrier-based multilevel PWM schemes are presented which help to optimize or balance the switch utilization in multilevel inverters. A 10-kW prototype six-level diode-clamped inverter has been built and controlled with the novel PWM strategies proposed in this paper to act as a voltage-source inverter for a motor drive.

  1. Multilevel cascade voltage source inverter with seperate DC sources

    DOEpatents

    Peng, Fang Zheng; Lai, Jih-Sheng

    2002-01-01

    A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.

  2. Multilevel cascade voltage source inverter with seperate DC sources

    DOEpatents

    Peng, Fang Zheng; Lai, Jih-Sheng

    1997-01-01

    A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.

  3. Multilevel cascade voltage source inverter with separate DC sources

    DOEpatents

    Peng, F.Z.; Lai, J.S.

    1997-06-24

    A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations. 15 figs.

  4. Multilevel cascade voltage source inverter with seperate DC sources

    DOEpatents

    Peng, Fang Zheng; Lai, Jih-Sheng

    2001-04-03

    A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.

  5. Soft Switching SEPP High Frequency Inverter for Induction Heating

    NASA Astrophysics Data System (ADS)

    Ogiwara, Hiroyuki; Nakaoka, Mutsuo

    This paper presents a novel circuit topology to attain soft switching operation of a high frequency inverter. Its output power is regulated over a wide range using a PWM control technique by connecting an auxiliary resonant circuit to the conventional single ended push pull (SEPP) high frequency inverter for induction heating. All switching devices in the proposed inverter are operated soft switching mode. This paper describes its circuit constitution and obtained experimental results from a practical point of view.

  6. Apollo 14 inverted pigeonites - Possible samples of lunar plutonic rocks.

    NASA Technical Reports Server (NTRS)

    Papike, J. J.; Bence, A. E.

    1972-01-01

    Analysis of 'inverted pigeonites' found in Apollo 14 samples 14082 and 14083 (a polymict breccia, the 'white rock') by a combination of optical, electron probe, and single-crystal X-ray diffraction techniques. These 'inverted pigeonites' are regarded as samples of plutonic rocks that have been blasted out of the Imbrium Basin. It is also concluded that lunar pigeonites will invert to orthopyroxenes, given sufficiently slow cooling histories even in very anhydrous environments.

  7. Repeat Customer Success in Extension

    ERIC Educational Resources Information Center

    Bess, Melissa M.; Traub, Sarah M.

    2013-01-01

    Four multi-session research-based programs were offered by two Extension specialist in one rural Missouri county. Eleven participants who came to multiple Extension programs could be called "repeat customers." Based on the total number of participants for all four programs, 25% could be deemed as repeat customers. Repeat customers had…

  8. An inverter/controller subsystem optimized for photovoltaic applications

    NASA Technical Reports Server (NTRS)

    Pickrell, R. L.; Osullivan, G.; Merrill, W. C.

    1978-01-01

    Conversion of solar array dc power to ac power stimulated the specification, design, and simulation testing of an inverter/controller subsystem tailored to the photovoltaic power source characteristics. Optimization of the inverter/controller design is discussed as part of an overall photovoltaic power system designed for maximum energy extraction from the solar array. The special design requirements for the inverter/ controller include: a power system controller (PSC) to control continuously the solar array operating point at the maximum power level based on variable solar insolation and cell temperatures; and an inverter designed for high efficiency at rated load and low losses at light loadings to conserve energy.

  9. Integral inverter/battery charger for use in electric vehicles

    NASA Technical Reports Server (NTRS)

    Thimmesch, D.

    1983-01-01

    The design and test results of a thyristor based inverter/charger are discussed. A battery charger is included integral to the inverter by using a subset of the inverter power circuit components. The resulting charger provides electrical isolation between the vehicle propulsion battery and ac line and is capable of charging a 25 kWh propulsion battery in 8 hours from a 220 volt ac line. The integral charger employs the inverter commutation components at a resonant ac/dc isolated converter rated at 3.6 kW. Charger efficiency and power factor at an output power of 3.6 kW are 86% and 95% respectively. The inverter, when operated with a matching polyphase ac induction motor and nominal 132 volt propulsion battery, can provide a peak shaft power of 34 kW (45 ph) during motoring operation and 45 kW (60 hp) during regeneration. Thyristors are employed for the inverter power switching devices and are arranged in an input-commutated topology. This configuration requires only two thyristors to commutate the six main inverter thyristors. Inverter efficiency during motoring operation at motor shaft speeds above 450 rad/sec (4300 rpm) is 92-94% for output power levels above 11 KW (15 hp). The combined ac inverter/charger package weighs 47 kg (103 lbs).

  10. Inverted Face Processing in Body Dysmorphic Disorder

    PubMed Central

    Feusner, Jamie D.; Moller, Hayley; Altstein, Lily; Sugar, Catherine; Bookheimer, Susan; Yoon, Joanne; Hembacher, Emily

    2010-01-01

    Individuals with body dysmorphic disorder (BDD) are preoccupied with perceived defects in appearance. Preliminary evidence suggests abnormalities in global and local visual information processing. The objective of this study was to compare global and local processing in BDD subjects and healthy controls by testing the face inversion effect, in which inverted (upside-down) faces are recognized more slowly and less accurately relative to upright faces. Eighteen medication-free subjects with BDD and 17 matched, healthy controls performed a recognition task with sets of upright and inverted faces on a computer screen that were either presented for short duration (500 msec) or long duration (5000 msec). Response time and accuracy rates were analyzed using linear and logistic mixed effects models, respectively. Results indicated that the inversion effect for response time was smaller in BDD subjects than controls during the long duration stimuli, but was not significantly different during the short duration stimuli. Inversion effect on accuracy rates did not differ significantly between groups during either of the two durations. Lesser inversion effect in BDD subjects may be due to greater detail-oriented and piecemeal processing for long duration stimuli. Similar results between groups for short duration stimuli suggest that they may be normally engaging configural and holistic processing for brief presentations. Abnormal visual information processing in BDD may contribute to distorted perception of appearance; this may not be limited to their own faces, but to others’ faces as well. PMID:20434170

  11. Dual Mode Inverter Control Test Verification

    SciTech Connect

    Bailey, J.M.

    2001-04-25

    Permanent Magnet Motors with either sinusoidal back emf (permanent magnet synchronous motor [PMSM]) or trapezoidal back emf (brushless dc motor [BDCM]) do not have the ability to alter the air gap flux density (field weakening). Since the back emf increases with speed, the system must be designed to operate with the voltage obtained at its highest speed. Oak Ridge National Laboratory's (ORNL) Power Electronics and Electric Machinery Research Center (PEEMRC) has developed a dual mode inverter controller (DMIC) that overcomes this disadvantage. This report summarizes the results of tests to verify its operation. The standard PEEMRC 75 kW hard-switched inverter was modified to implement the field weakening procedure (silicon controlled rectifier enabled phase advance). A 49.5 hp motor rated at 2800 rpm was derated to a base of 400 rpm and 7.5 hp. The load developed by a Kahn Industries hydraulic dynamometer, was measured with a MCRT9-02TS Himmelstein and Company torque meter. At the base conditions a current of 212 amperes produced the 7.5 hp. Tests were run at 400, 1215, and 2424 rpm. In each run, the current was no greater than 214 amperes. The horsepower obtained in the three runs were 7.5, 9.3, and 8.12. These results verified the basic operation of the DMIC in producing a Constant Power Speed Ratios (CPSR) of six.

  12. Inverting dedevelopment: geometric singularity theory in embryology

    NASA Astrophysics Data System (ADS)

    Bookstein, Fred L.; Smith, Bradley R.

    2000-10-01

    The diffeomorphism model so useful in the biomathematics of normal morphological variability and disease is inappropriate for applications in embryogenesis, where whole coordinate patches are created out of single points. For this application we need a suitable algebra for the creation of something from nothing in a carefully organized geometry: a formalism for parameterizing discrete nondifferentiabilities of invertible functions on Rk, k $GTR 1. One easy way to begin is via the inverse of the development map - call it the dedevelopment map, the deformation backwards in time. Extrapolated, this map will inevitably have singularities at which its derivative is zero. When the dedevelopment map is inverted to face forward in time, the singularities become appropriately isolated infinities of derivative. We have recently introduced growth visualizations via extrapolations to the isolated singularities at which only one directional derivative is zero. Maps inverse to these create new coordinate patches directionally rather than radically. The most generic singularity that suits this purpose is the crease f(x,y) equals (x,x2y+y3), which has already been applied in morphometrics for the description of focal morphogenetic phenomena. We apply it to embryogenesis in the form of its analytic inverse, and demonstrate its power using a priceless new data set of mouse embryos imaged in 3D by micro-MR with voxels smaller than 100micrometers 3.

  13. Series resonance inverter with triggered vacuum gaps

    NASA Astrophysics Data System (ADS)

    Damstra, Geert C.; Zhang, X.

    1994-05-01

    Series resonance inverters based on semi-conductor switching elements are well-known and have a wide range of application, mainly for lower voltages. For high voltage application many switching elements have to be put in series to obtain sufficient blocking voltage. Voltage grinding and multiple gate control elements are needed. There is much experience with the triggered vacuum gaps as high voltage/high current single shot elements, for example in reignition circuits for synthetic circuit breaker tests. These elements have a blocking voltage of 50 - 100 kV and are triggerable by a light fiber control device. A prototype inverter has been developed that generates 0.1 Hz, 30 kV AC voltages with a flat top for tests on cables and capacitors of many micro farads fed from a low voltage supply of about 600 V. Only two TVG elements are needed to switch the resonant circuit alternatively on the positive or negative supply. The resonant circuit itself consists of the capacitance of the testobject and a high quality inductor that determines the frequency and the peak current of the voltage reversing process.

  14. Lightweight PV Inverters: Dual Bi-Directional IGBTs Modules Enables Breakthrough PV Inverter Using Current Modulation Topology

    SciTech Connect

    2012-01-30

    Solar ADEPT Project: PV inverters convert DC power generated by modules into usable AC power. IPC’s initial 30kW 94lb. PV inverter reduces the weight of comparable 30kW PV inverters by 90%—reducing the cost of materials, manufacturing, shipping, and installation. With ARPA-E support, new bi-directional silicon power switches will be developed, commercialized, and utilized in IPC’s next-generation PV inverter. With these components, IPC will produce 100kW inverters that weight less than 100lb., reducing the weight of conventional 3,000lb. 100kW inverters by more than 95%. The new power switches will cut IPC’s $/W manufacturing cost in half, as well as further reduce indirect shipping and installation costs.

  15. RepeatsDB: a database of tandem repeat protein structures

    PubMed Central

    Di Domenico, Tomás; Potenza, Emilio; Walsh, Ian; Gonzalo Parra, R.; Giollo, Manuel; Minervini, Giovanni; Piovesan, Damiano; Ihsan, Awais; Ferrari, Carlo; Kajava, Andrey V.; Tosatto, Silvio C.E.

    2014-01-01

    RepeatsDB (http://repeatsdb.bio.unipd.it/) is a database of annotated tandem repeat protein structures. Tandem repeats pose a difficult problem for the analysis of protein structures, as the underlying sequence can be highly degenerate. Several repeat types haven been studied over the years, but their annotation was done in a case-by-case basis, thus making large-scale analysis difficult. We developed RepeatsDB to fill this gap. Using state-of-the-art repeat detection methods and manual curation, we systematically annotated the Protein Data Bank, predicting 10 745 repeat structures. In all, 2797 structures were classified according to a recently proposed classification schema, which was expanded to accommodate new findings. In addition, detailed annotations were performed in a subset of 321 proteins. These annotations feature information on start and end positions for the repeat regions and units. RepeatsDB is an ongoing effort to systematically classify and annotate structural protein repeats in a consistent way. It provides users with the possibility to access and download high-quality datasets either interactively or programmatically through web services. PMID:24311564

  16. View of the upper part of the Inverted Siphon showing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of the upper part of the Inverted Siphon showing sandbox at the top of the slope before dropping into the Hot Water (or White) Canyon. Looking northeast - Childs-Irving Hydroelectric Project, Irving System, Inverted Siphon, Forest Service Road 708/502, Camp Verde, Yavapai County, AZ

  17. Three-phase inverter for small high speed motors

    NASA Astrophysics Data System (ADS)

    McCormick, John A.; Valenzuela, Javier A.

    1991-07-01

    A high-frequency three-phase inverter is being developed to drive a miniature centrifugal compressor which is a key component in a long-life space-borne cryocooler. The inverter is a unique transformer-coupled design, tailored to the low-voltage high-current characteristic of the compressor's induction motor. The design and performance demonstration of a breadboard model of the inverter are described. The cryocooler uses a reverse-Brayton cycle with turbomachines to provide 5 watt of cooling at 70 K. The design target for input power to the compressor motor is 175 watts. Line-to-neutral phase voltage waveforms to be supplied by the inverter have an amplitude of 15 volt-rms at a frequency of 8 kHz. DC power at 28 volt is supplied to the inverter. The breadboard inverter was tested with a preliminary development model of the compressor. It drove the compressor over a range of operating conditions encompassing frequencies of 5 to 9 kHz at powers of 56 to 437 watt. Inverter efficiencies, calculated from experimentally verified loss models, ranged from 89 to 95 percent over the tests. The design target on efficiency is 90 percent. The inverter was demonstrated to supply starting current adequate to overcome the starting friction of the compressor's self-acting gas bearings by a safe margin.

  18. Three-phase inverter for small high speed motors

    NASA Technical Reports Server (NTRS)

    Mccormick, John A.; Valenzuela, Javier A.

    1991-01-01

    A high-frequency three-phase inverter is being developed to drive a miniature centrifugal compressor which is a key component in a long-life space-borne cryocooler. The inverter is a unique transformer-coupled design, tailored to the low-voltage high-current characteristic of the compressor's induction motor. The design and performance demonstration of a breadboard model of the inverter are described. The cryocooler uses a reverse-Brayton cycle with turbomachines to provide 5 watt of cooling at 70 K. The design target for input power to the compressor motor is 175 watts. Line-to-neutral phase voltage waveforms to be supplied by the inverter have an amplitude of 15 volt-rms at a frequency of 8 kHz. DC power at 28 volt is supplied to the inverter. The breadboard inverter was tested with a preliminary development model of the compressor. It drove the compressor over a range of operating conditions encompassing frequencies of 5 to 9 kHz at powers of 56 to 437 watt. Inverter efficiencies, calculated from experimentally verified loss models, ranged from 89 to 95 percent over the tests. The design target on efficiency is 90 percent. The inverter was demonstrated to supply starting current adequate to overcome the starting friction of the compressor's self-acting gas bearings by a safe margin.

  19. Results of Sandia National Laboratories grid-tied inverter testing

    SciTech Connect

    Kern, G.A.; Bonn, R.H.; Ginn, J.; Gonzalez, S.

    1998-07-01

    This paper proposes a definition for a Non-Islanding Inverter. This paper also presents methods that can be used to implement such an inverter, along with references to prior work on the subject. Justification for the definition is provided on both a theoretical basis and results from tests conducted at Sandia National Laboratories and Ascension Technology, Inc.

  20. Linear control of the flywheel inverted pendulum.

    PubMed

    Olivares, Manuel; Albertos, Pedro

    2014-09-01

    The flywheel inverted pendulum is an underactuated mechanical system with a nonlinear model but admitting a linear approximation around the unstable equilibrium point in the upper position. Although underactuated systems usually require nonlinear controllers, the easy tuning and understanding of linear controllers make them more attractive for designers and final users. In a recent paper, a simple PID controller was proposed by the authors, leading to an internally unstable controlled plant. To achieve global stability, two options are developed here: first by introducing an internal stabilizing controller and second by replacing the PID controller by an observer-based state feedback control. Simulation and experimental results show the effectiveness of the design. PMID:24480638

  1. HOLLOTRON switch for megawatt lightweight space inverters

    NASA Technical Reports Server (NTRS)

    Poeschel, R. L.; Goebel, D. M.; Schumacher, R. W.

    1991-01-01

    The feasibility of satisfying the switching requirements for a megawatt ultralight inverter system using HOLLOTRON switch technology was determined. The existing experimental switch hardware was modified to investigate a coaxial HOLLOTRON switch configuration and the results were compared with those obtained for a modified linear HOLLOTRON configuration. It was concluded that scaling the HOLLOTRON switch to the current and voltage specifications required for a megawatt converter system is indeed feasible using a modified linear configuration. The experimental HOLLOTRON switch operated at parameters comparable to the scaled coaxial HOLLOTRON. However, the linear HOLLOTRON data verified the capability for meeting all the design objectives simultaneously including current density (greater than 2 A/sq cm), voltage (5 kV), switching frequency (20 kHz), switching time (300 ns), and forward voltage drop (less than or equal to 20 V). Scaling relations were determined and a preliminary design was completed for an engineering model linear HOLLOTRON switch to meet the megawatt converter system specifications.

  2. Scalar field cosmologies with inverted potentials

    NASA Astrophysics Data System (ADS)

    Boisseau, B.; Giacomini, H.; Polarski, D.

    2015-10-01

    Regular bouncing solutions in the framework of a scalar-tensor gravity model were found in a recent work. We reconsider the problem in the Einstein frame (EF) in the present work. Singularities arising at the limit of physical viability of the model in the Jordan frame (JF) are either of the Big Bang or of the Big Crunch type in the EF. As a result we obtain integrable scalar field cosmological models in general relativity (GR) with inverted double-well potentials unbounded from below which possess solutions regular in the future, tending to a de Sitter space, and starting with a Big Bang. The existence of the two fixed points for the field dynamics at late times found earlier in the JF becomes transparent in the EF.

  3. A high performance current source inverter

    SciTech Connect

    Joos, G.; Moschopoulos, G.; Ziogas, P.D.

    1993-10-01

    A recent innovation in current source inverter (CSI) drives has been the introduction of pulsewidth modulation (PWM) for the purpose of improving the quality of the load currents and voltages. However, the typical six switch CSI circuit is not compatible with all standard PWM techniques thus limiting the number of schemes that can be used. The modified CSI circuit discussed in this paper removes most of the restrictions at the ``cost`` of an extra switch. Additional advantages include faster response times through modulation index control and higher efficiency. This paper includes a detailed steady-state analysis and design procedure. The feasibility and performance of the modified CSI are verified by simulation and experimental implementation on a 5 kVA converter.

  4. Alkaline degradation of invert sugar from molasses.

    PubMed

    Yang, Byung Y; Montgomery, Rex

    2007-11-01

    Sugar beet and sugar cane molasses have been shown to be suitable starting materials for producing de-icer preparations. The sucrose in the molasses is hydrolyzed to glucose and fructose by invertase. The reducing sugars are then degraded by NaOH, the alkali being neutralized by the sugar acids produced, resulting in an increase of the ionic strength and consequently depression of the freezing point of the resulting solution. For the preparation of de-icers, the desired freezing point depression to a temperature of less than about -20 degrees C can be achieved by adjusting the amount and concentration of the alkali metal hydroxide used. The resulting products are biodegradable and eliminate the corrosive effects associated with the use of conventional chloride salts. Degradation of invert sugar by NaOH has been achieved without an external heat source. The reaction products showed the same freezing point depression as seen in the degradation products from pure glucose. PMID:17222551

  5. Highly efficient fully transparent inverted OLEDs

    NASA Astrophysics Data System (ADS)

    Meyer, J.; Winkler, T.; Hamwi, S.; Schmale, S.; Kröger, M.; Görrn, P.; Johannes, H.-H.; Riedl, T.; Lang, E.; Becker, D.; Dobbertin, T.; Kowalsky, W.

    2007-09-01

    One of the unique selling propositions of OLEDs is their potential to realize highly transparent devices over the visible spectrum. This is because organic semiconductors provide a large Stokes-Shift and low intrinsic absorption losses. Hence, new areas of applications for displays and ambient lighting become accessible, for instance, the integration of OLEDs into the windshield or the ceiling of automobiles. The main challenge in the realization of fully transparent devices is the deposition of the top electrode. ITO is commonly used as transparent bottom anode in a conventional OLED. To obtain uniform light emission over the entire viewing angle and a low series resistance, a TCO such as ITO is desirable as top contact as well. However, sputter deposition of ITO on top of organic layers causes damage induced by high energetic particles and UV radiation. We have found an efficient process to protect the organic layers against the ITO rf magnetron deposition process of ITO for an inverted OLED (IOLED). The inverted structure allows the integration of OLEDs in more powerful n-channel transistors used in active matrix backplanes. Employing the green electrophosphorescent material Ir(ppy) 3 lead to IOLED with a current efficiency of 50 cd/A and power efficiency of 24 lm/W at 100 cd/m2. The average transmittance exceeds 80 % in the visible region. The on-set voltage for light emission is lower than 3 V. In addition, by vertical stacking we achieved a very high current efficiency of more than 70 cd/A for transparent IOLED.

  6. Inverting Magnetic Data Using Parallel Processing

    NASA Astrophysics Data System (ADS)

    Connor, L. M.; Connor, C. B.

    2002-12-01

    We have collaborated to develop an innovative method for inverting magnetic data from high-resolution geomagnetic maps. Our method uses parallel computations and asynchronous communication among multiple nodes of a Beowulf cluster to produce geologically constrained 3-D models of magnetic anomalies. This modeling effort comes in response to the current revolution in gathering geophysical data. Interfacing kinematic differential GPS to magnetometers has presented geo-scientists with the daunting task of interpreting very high-resolution geomagnetic maps. Traditional methods of data interpretation, such as forward modeling, are sorely taxed. Our method manipulates a set of geologically constrained parameters to eventually build a geometric model that accurately represents the magnetic anomaly. Iterations of the code execute in parallel on multiple networked nodes via MPI, a message passing interface. Each node computes a magnetic solution at different geographical field locations based on a modeled set of geological parameters, using various forward calculations. The parameter sets are continually adjusted by the downhill simplex method. Calculated values are continually compared to the observed data using a goodness-of-fit test until all parameter sets generate the same result within a specified tolerance. A set of parameters producing an anomaly mimicking the observed anomaly is the result. By changing bounds on input parameters it is practical to quickly identify equivalent solutions. These techniques are applied to a high resolution geomagnetic data set consisting of 30,000 data points and four discrete magnetic anomalies. Data were smoothed and inverted using the parallel code. The subsurface was discretized and the depth to each unit, magnetization, and depth to the base of the entire structure were allowed to vary as independent parameters. Inversion clearly highlights volcanic features of the source rocks, including the truncated cone, crater, lava flows, and

  7. Repetition probability effects for inverted faces.

    PubMed

    Grotheer, Mareike; Hermann, Petra; Vidnyánszky, Zoltán; Kovács, Gyula

    2014-11-15

    It has been shown, that the repetition related reduction of the blood-oxygen level dependent (BOLD) signal is modulated by the probability of repetitions (P(rep)) for faces (Summerfield et al., 2008), providing support for the predictive coding (PC) model of visual perception (Rao and Ballard, 1999). However, the stage of face processing where repetition suppression (RS) is modulated by P(rep) is still unclear. Face inversion is known to interrupt higher level configural/holistic face processing steps and if modulation of RS by P(rep) takes place at these stages of face processing, P(rep) effects are expected to be reduced for inverted when compared to upright faces. Therefore, here we aimed at investigating whether P(rep) effects on RS observed for face stimuli originate at the higher-level configural/holistic stages of face processing by comparing these effects for upright and inverted faces. Similarly to previous studies, we manipulated P(rep) for pairs of stimuli in individual blocks of fMRI recordings. This manipulation significantly influenced repetition suppression in the posterior FFA, the OFA and the LO, independently of stimulus orientation. Our results thus reveal that RS in the ventral visual stream is modulated by P(rep) even in the case of face inversion and hence strongly compromised configural/holistic face processing. An additional whole-brain analysis could not identify any areas where the modulatory effect of probability was orientation specific either. These findings imply that P(rep) effects on RS might originate from the earlier stages of face processing. PMID:25123974

  8. Improved PWM control for GTO inverters with pulse number modulation

    SciTech Connect

    Tadakuma, Susuma; Tanaka, Shigeru; Miura, Kazutoshi; Ofosu-Amaah, W.

    1996-05-01

    This paper proposes pulse number modulation (PNM)-assisted pulse-width modulation (PWM) control to improve the modulation factor of bridge inverters and to solve voltage uncontrollability in neutral point clamped (NPC) inverters. The basic idea is to enlarge the linear region of PWM control via PNM technology. The authors will show the following through simulation and experimental results: (1) conventional bridge inverters can utilize at most 80% of the nominal inverter capacity because of the limit of the modulation factor. The PWM and PNM combined control is able to improve the modulation factor up to approximately 1.0; (2) the PWM and PNM control enables linear voltage control in the NPC inverter even for an extremely small reference. The PNM technology also contributes to a reduction in switching losses.

  9. Transistorized PWM inverter-induction motor drive system

    NASA Technical Reports Server (NTRS)

    Peak, S. C.; Plunkett, A. B.

    1982-01-01

    This paper describes the development of a transistorized PWM inverter-induction motor traction drive system. A vehicle performance analysis was performed to establish the vehicle tractive effort-speed requirements. These requirements were then converted into a set of inverter and motor specifications. The inverter was a transistorized three-phase bridge using General Electric power Darlington transistors. The description of the design and development of this inverter is the principal object of this paper. The high-speed induction motor is a design which is optimized for use with an inverter power source. The primary feedback control is a torque angle control with voltage and torque outer loop controls. A current-controlled PWM technique is used to control the motor voltage. The drive has a constant torque output with PWM operation to base motor speed and a constant horsepower output with square wave operation to maximum speed. The drive system was dynamometer tested and the results are presented.

  10. Evaluation of a high power inverter for potential space applications

    NASA Technical Reports Server (NTRS)

    Guynes, B. V.; Lanier, J. R., Jr.

    1976-01-01

    The ADM-006 inverter discussed utilizes a unique method of using power switching circuits to produce three-phase low harmonic content voltages without any significant filtering. This method is referred to as the power center approach to inverter design and is explained briefly. The results are presented of tests performed by MSFC to evaluate inverter performance, especially when required to provide power to nonlinear loads such as half or full wave rectified loads with capacitive filtering. Test preocedures and results are described. These tests show that the power center inverter essentially met or exceeded all of claims excluding voltage regulation (3.9 percent versus specified 3.3 percent) and would be a good candidate for high power inverter applications such as may be found on Space Station, Spacelab, etc.

  11. Inverter Modeling For Accurate Energy Predictions Of Tracking HCPV Installations

    NASA Astrophysics Data System (ADS)

    Bowman, J.; Jensen, S.; McDonald, Mark

    2010-10-01

    High efficiency high concentration photovoltaic (HCPV) solar plants of megawatt scale are now operational, and opportunities for expanded adoption are plentiful. However, effective bidding for sites requires reliable prediction of energy production. HCPV module nameplate power is rated for specific test conditions; however, instantaneous HCPV power varies due to site specific irradiance and operating temperature, and is degraded by soiling, protective stowing, shading, and electrical connectivity. These factors interact with the selection of equipment typically supplied by third parties, e.g., wire gauge and inverters. We describe a time sequence model accurately accounting for these effects that predicts annual energy production, with specific reference to the impact of the inverter on energy output and interactions between system-level design decisions and the inverter. We will also show two examples, based on an actual field design, of inverter efficiency calculations and the interaction between string arrangements and inverter selection.

  12. Saturation of repeated quantum measurements

    NASA Astrophysics Data System (ADS)

    Haapasalo, Erkka; Heinosaari, Teiko; Kuramochi, Yui

    2016-08-01

    We study sequential measurement scenarios where the system is repeatedly subjected to the same measurement process. We first provide examples of such repeated measurements where further repetitions of the measurement do not increase our knowledge on the system after some finite number of measurement steps. We also prove, however, that repeating the Lüders measurement of an unsharp two-outcome observable never saturates in this sense, and we characterize the observable measured in the limit of infinitely many repetitions. Our result implies that a repeated measurement can be used to correct the inherent noise of an unsharp observable.

  13. Inverted teats (Mammillae invertitae) in gilts - effect on piglet survival and growth rate.

    PubMed

    Chalkias, H; Ekman, E; Lundeheim, N; Rydhmer, L; Jacobson, M

    2014-06-01

    In the modern pig industry, the increasing number of piglets born per litter augments the importance of the number of functional teats in the sow. The aim of this study was to evaluate the function and importance of inverted teats during nursing and to analyze structural and functional differences between the mammary glands of inverted teats versus normal teats. Nine farrowing gilts (8 purebred Swedish Yorkshire gilts and 1 cross between Swedish Yorkshire and Norwegian Landrace) and 94 piglets (59 piglets suckling normal teats, 32 piglets suckling protruded teats [i.e., previously inverted], 2 piglets suckling inverted teats, and 3 piglets suckling considerably smaller teats) were included in the study. Teat fidelity (keeping the same teat between the nursings) was registered, excluding the first 48 h postpartum. Piglet weight was recorded daily during the first week of life and thereafter once a week until weaning at 4 wk of age. Weight and growth rate were analyzed using repeated observation mixed-model analysis of variance. The 2 piglets that suckled the inverted teats were not able to emerge the teats and they were euthanized 4 and 8 d after birth, respectively, due to loss of BW. The average weight at weaning (28 d of age) was 8.1 kg (range 3.2-13.8 kg). In the normal teats (n = 53), the weight of the corresponding mammary gland tissue at necropsy was positively correlated to the piglet average daily weight gain during wk 2 (r = 0.33, P < 0.05), 3 (r = 0.55, P < 0.001), and 4 (r = 0.47, P < 0.001). In the protruded teats (n = 32), the weight of the corresponding mammary gland tissue was positively correlated to the piglet average daily weight gain during wk 2 (r = 0.63, P < 0.001) and 3 (r = 0.43, P < 0.05). Among the piglets nursing normal teats, 82% kept fidelity to its teat and the corresponding percent for the protruded teats was 26%. In 7 of the 9 sows, the weaning weight of the piglets suckling protruded teats was numerically lower compared to the

  14. All-photonic quantum repeaters

    PubMed Central

    Azuma, Koji; Tamaki, Kiyoshi; Lo, Hoi-Kwong

    2015-01-01

    Quantum communication holds promise for unconditionally secure transmission of secret messages and faithful transfer of unknown quantum states. Photons appear to be the medium of choice for quantum communication. Owing to photon losses, robust quantum communication over long lossy channels requires quantum repeaters. It is widely believed that a necessary and highly demanding requirement for quantum repeaters is the existence of matter quantum memories. Here we show that such a requirement is, in fact, unnecessary by introducing the concept of all-photonic quantum repeaters based on flying qubits. In particular, we present a protocol based on photonic cluster-state machine guns and a loss-tolerant measurement equipped with local high-speed active feedforwards. We show that, with such all-photonic quantum repeaters, the communication efficiency scales polynomially with the channel distance. Our result paves a new route towards quantum repeaters with efficient single-photon sources rather than matter quantum memories. PMID:25873153

  15. Sequence repeats and protein structure

    NASA Astrophysics Data System (ADS)

    Hoang, Trinh X.; Trovato, Antonio; Seno, Flavio; Banavar, Jayanth R.; Maritan, Amos

    2012-11-01

    Repeats are frequently found in known protein sequences. The level of sequence conservation in tandem repeats correlates with their propensities to be intrinsically disordered. We employ a coarse-grained model of a protein with a two-letter amino acid alphabet, hydrophobic (H) and polar (P), to examine the sequence-structure relationship in the realm of repeated sequences. A fraction of repeated sequences comprises a distinct class of bad folders, whose folding temperatures are much lower than those of random sequences. Imperfection in sequence repetition improves the folding properties of the bad folders while deteriorating those of the good folders. Our results may explain why nature has utilized repeated sequences for their versatility and especially to design functional proteins that are intrinsically unstructured at physiological temperatures.

  16. All-photonic quantum repeaters

    NASA Astrophysics Data System (ADS)

    Azuma, Koji; Tamaki, Kiyoshi; Lo, Hoi-Kwong

    2015-04-01

    Quantum communication holds promise for unconditionally secure transmission of secret messages and faithful transfer of unknown quantum states. Photons appear to be the medium of choice for quantum communication. Owing to photon losses, robust quantum communication over long lossy channels requires quantum repeaters. It is widely believed that a necessary and highly demanding requirement for quantum repeaters is the existence of matter quantum memories. Here we show that such a requirement is, in fact, unnecessary by introducing the concept of all-photonic quantum repeaters based on flying qubits. In particular, we present a protocol based on photonic cluster-state machine guns and a loss-tolerant measurement equipped with local high-speed active feedforwards. We show that, with such all-photonic quantum repeaters, the communication efficiency scales polynomially with the channel distance. Our result paves a new route towards quantum repeaters with efficient single-photon sources rather than matter quantum memories.

  17. All-photonic quantum repeaters.

    PubMed

    Azuma, Koji; Tamaki, Kiyoshi; Lo, Hoi-Kwong

    2015-01-01

    Quantum communication holds promise for unconditionally secure transmission of secret messages and faithful transfer of unknown quantum states. Photons appear to be the medium of choice for quantum communication. Owing to photon losses, robust quantum communication over long lossy channels requires quantum repeaters. It is widely believed that a necessary and highly demanding requirement for quantum repeaters is the existence of matter quantum memories. Here we show that such a requirement is, in fact, unnecessary by introducing the concept of all-photonic quantum repeaters based on flying qubits. In particular, we present a protocol based on photonic cluster-state machine guns and a loss-tolerant measurement equipped with local high-speed active feedforwards. We show that, with such all-photonic quantum repeaters, the communication efficiency scales polynomially with the channel distance. Our result paves a new route towards quantum repeaters with efficient single-photon sources rather than matter quantum memories. PMID:25873153

  18. Estimating repeatability of egg size

    USGS Publications Warehouse

    Flint, P.L.; Rockwell, R.F.; Sedinger, J.S.

    2001-01-01

    Measures of repeatability have long been used to assess patterns of variation in egg size within and among females. We compared different analytical approaches for estimating repeatability of egg size of Black Brant. Separate estimates of repeatability for eggs of each clutch size and laying sequence number varied from 0.49 to 0.64. We suggest that using the averaging egg size within clutches results in underestimation of variation within females and thereby overestimates repeatability. We recommend a nested design that partitions egg-size variation within clutches, among clutches within females, and among females. We demonstrate little variation in estimates of repeatability resulting from a nested model controlling for egg laying sequence and a nested model in which we assumed laying sequence was unknown.

  19. A PWM transistor inverter for an ac electric vehicle drive

    NASA Technical Reports Server (NTRS)

    Slicker, J. M.

    1981-01-01

    A prototype system consisting of closely integrated motor, inverter, and transaxle has been built in order to demonstrate the feasibility of a three-phase ac transistorized inverter for electric vehicle applications. The microprocessor-controlled inverter employs monolithic power transistors to drive an oil-cooled, three-phase induction traction motor at a peak output power of 30 kW from a 144 V battery pack. Transistor safe switching requirements are discussed, and a circuit is presented for recovering trapped snubber inductor energy at transistor turn-off.

  20. One-Cycle Controlled Single Phase UPS Inverter

    NASA Astrophysics Data System (ADS)

    Xiangli, Li; Hanhong, Qi

    A one-cycle controlled single-phase full-bridge DC-AC inverter is proposed. One-cycle control is a nonlinear control method which has fast transient response and good tracking performance. The one-cycle control immunizes the inverter against the perturbation of input dc bus and provides well system dynamic regulation with hybrid sinusoidal PWM control. The basic operational theory and control method are discussed in this paper. Finally, simulation waveforms and experimental results are given. The simulation and experimental results demonstrate the effectiveness of this control technique for inverters in UPS applications, especially when nonlinear loads must to be supplied and line has large undesirable harmonic components.

  1. Electric machine and current source inverter drive system

    DOEpatents

    Hsu, John S

    2014-06-24

    A drive system includes an electric machine and a current source inverter (CSI). This integration of an electric machine and an inverter uses the machine's field excitation coil for not only flux generation in the machine but also for the CSI inductor. This integration of the two technologies, namely the U machine motor and the CSI, opens a new chapter for the component function integration instead of the traditional integration by simply placing separate machine and inverter components in the same housing. Elimination of the CSI inductor adds to the CSI volumetric reduction of the capacitors and the elimination of PMs for the motor further improve the drive system cost, weight, and volume.

  2. An iterative method to invert the LTSn matrix

    SciTech Connect

    Cardona, A.V.; Vilhena, M.T. de

    1996-12-31

    Recently Vilhena and Barichello proposed the LTSn method to solve, analytically, the Discrete Ordinates Problem (Sn problem) in transport theory. The main feature of this method consist in the application of the Laplace transform to the set of Sn equations and solve the resulting algebraic system for the transport flux. Barichello solve the linear system containing the parameter s applying the definition of matrix invertion exploiting the structure of the LTSn matrix. In this work, it is proposed a new scheme to invert the LTSn matrix, decomposing it in blocks and recursively inverting this blocks.

  3. Skull Base Inverted Papilloma: A Comprehensive Review

    PubMed Central

    Wassef, Shafik N.; Batra, Pete S.; Barnett, Samuel

    2012-01-01

    Skull base inverted papilloma (IP) is an unusual entity for many neurosurgeons. IP is renowned for its high rate of recurrence, its ability to cause local destruction, and its association with malignancy. This paper is a comprehensive review of the reports, studies, and reviews published in the current biomedical literature from 1947 to September 2010 and synthesize this information to focus on its potential invasion to the base of the skull and possible intradural extension. The objective is to familiarize the clinician with the different aspects of this unusual disease. The role of modern diagnostic tools in medical imaging in order to assess clearly the limits of the tumors and to enhance the efficiency and the safety in the choice of a surgical approach is pointed out. The treatment guidelines for IP have undergone a complex evolution that continues today. Radical excision of the tumour is technically difficult and often incomplete. Successful management of IP requires resection of the affected mucosa which could be achieved with open surgery, endoscopic, or combined approach. Radio and chemotherapy were used for certain indications. More optimally research would be a multicenter randomized trials with large size cohorts. PMID:23346418

  4. Inverted Metamorphic Multijunction (IMM) Cell Processing Instructions

    SciTech Connect

    Duda, A.; Ward, S.; Young, M.

    2012-02-01

    This technical report details the processing schedule used to fabricate Inverted Metamorphic Multijunction (IMM) concentrator solar cells at The National Renewable Energy Laboratory (NREL). These devices are used as experimental test structures to support the research at NREL that is focused on increasing the efficiency of photovoltaic power conversion. They are not intended to be devices suitable for deployment in working concentrator systems primarily because of heat sinking issues. The process schedule was developed to be compatible with small sample sizes and to afford relatively rapid turn-around times, in support of research efforts. The report describes the use of electro deposition of gold for both the back and front contacts. Electro-deposition is used because of its rapid turn around time and because it is a benign metallization technique that is seldom responsible for damage to the semiconductors. The layer transfer technique is detailed including the use of a commercially available adhesive and the etching away of the parent gallium arsenide substrate. Photolithography is used to define front contact grids as well as the mesa area of the cell. Finally, the selective wet chemical etchant system is introduced and its use to reveal the back contact is described.

  5. Faster Processing for Inverting GPS Occultation Data

    NASA Technical Reports Server (NTRS)

    Ao, Chi

    2004-01-01

    A document outlines a computational method that can be incorporated into two prior methods used to invert Global Positioning System (GPS) occultation data [signal data acquired by a low-Earth-orbiting satellite as either this or the GPS satellite rises above or falls below the horizon] to obtain information on altitude-dependent properties of the atmosphere. The two prior inversion methods, known as back propagation and canonical transform, are computationally expensive because for each occultation, they involve numerical evaluation of a large number of diffraction-like spatial integrals. The present method involves an angular-spectrum-based phase-extrapolation approximation in which each data point is associated with a plane-wave component that propagates in a unique direction from the orbit of the receiving satellite to intersect a straight line tangent to the orbit at a nearby point. This approximation enables the use of fast Fourier transforms (FFTs), which apply only to data collected along a straight-line trajectory. The computation of the diffraction-like integrals in the angular-spectrum domain by use of FFTs takes only seconds, whereas previously, it took minutes.

  6. Inverted Leidenfrost-like Effect during Condensation.

    PubMed

    Narhe, Ramchandra; Anand, Sushant; Rykaczewski, Konrad; Medici, Marie-Gabrielle; González-Viñas, Wenceslao; Varanasi, Kripa K; Beysens, Daniel

    2015-05-19

    Water droplets condensing on solidified phase change materials such as benzene and cyclohexane near their melting point show in-plane jumping and continuous "crawling" motion. The jumping drop motion has been tentatively explained as an outcome of melting and refreezing of the materials surface beneath the droplets and can be thus considered as an inverted Leidenfrost-like effect (in the classical case vapor is generated from a droplet on a hot substrate). We present here a detailed investigation of jumping movements using high-speed imaging and static cross-sectional cryogenic focused ion beam scanning electron microscope imaging. Our results show that drop motion is induced by a thermocapillary (Marangoni) effect. The in-plane jumping motion can be delineated to occur in two stages. The first stage occurs on a millisecond time scale and comprises melting the substrate due to drop condensation. This results in droplet depinning, partial spreading, and thermocapillary movement until freezing of the cyclohexane film. The second stage occurs on a second time scale and comprises relaxation motion of the drop contact line (change in drop contact radius and contact angle) after substrate freezing. When the cyclohexane film cannot freeze, the droplet continuously glides on the surface, resulting in the crawling motion. PMID:25807004

  7. Performance of an inverted ion source

    SciTech Connect

    Salvadori, M. C.; Teixeira, F. S.; Sgubin, L. G.; Araujo, W. W. R.; Spirin, R. E.; Oks, E. M.; Brown, I. G.

    2013-02-15

    Whereas energetic ion beams are conventionally produced by extracting ions (say, positive ions) from a plasma that is held at high (positive) potential, with ion energy determined by the potential drop through which the ions fall in the beam formation electrode system, in the device described here the plasma and its electronics are held at ground potential and the ion beam is formed and injected energetically into a space maintained at high (negative) potential. We refer to this configuration as an 'inverted ion source.' This approach allows considerable savings both technologically and economically, rendering feasible some ion beam applications, in particular small-scale ion implantation, that might otherwise not be possible for many researchers and laboratories. We have developed a device of this kind utilizing a metal vapor vacuum arc plasma source, and explored its operation and beam characteristics over a range of parameter variation. The downstream beam current has been measured as a function of extraction voltage (5-35 kV), arc current (50-230 A), metal ion species (Ti, Nb, Au), and extractor grid spacing and beamlet aperture size (3, 4, and 5 mm). The downstream ion beam current as measured by a magnetically-suppressed Faraday cup was up to as high as 600 mA, and with parametric variation quite similar to that found for the more conventional metal vapor vacuum arc ion source.

  8. Direct Comparison of Inverted and Non-Inverted Growths of GaInP Solar Cells: Preprint

    SciTech Connect

    Steiner, M. A.; Geisz, J. F.; Reedy Jr, R.C.; Kurtz, S.

    2008-05-01

    The inverted growth of III-V solar cells presents some specific challenges that are not present in regular, non-inverted growths. Because the highly doped top contact layer is grown first, followed by the lengthy high-temperature growth of the remainder of the structure, there is ample time for the dopants in the contact layer to diffuse away. This leads to an increase in the contact resistance to the top layer, and a corresponding drop in voltage. The diffusion of dopants in other layers is similarly altered with respect to the non-inverted configuration because of the change in growth sequence. We compare the dopant profiles of inverted and non-inverted structures by using secondary ion mass spectroscopy and correlate the results with the observed performance of the devices. We also describe a technique for growing a GaInAsN contact layer in the inverted configuration and show that it achieves a specific contact resistance comparable to what is normally observed in non-inverted cells.

  9. Triple inverter pierce oscillator circuit suitable for CMOS

    DOEpatents

    Wessendorf; Kurt O.

    2007-02-27

    An oscillator circuit is disclosed which can be formed using discrete field-effect transistors (FETs), or as a complementary metal-oxide-semiconductor (CMOS) integrated circuit. The oscillator circuit utilizes a Pierce oscillator design with three inverter stages connected in series. A feedback resistor provided in a feedback loop about a second inverter stage provides an almost ideal inverting transconductance thereby allowing high-Q operation at the resonator-controlled frequency while suppressing a parasitic oscillation frequency that is inherent in a Pierce configuration using a "standard" triple inverter for the sustaining amplifier. The oscillator circuit, which operates in a range of 10 50 MHz, has applications for use as a clock in a microprocessor and can also be used for sensor applications.

  10. Stability of Brillouin flow in planar, conventional, and inverted magnetrons

    NASA Astrophysics Data System (ADS)

    Simon, D. H.; Lau, Y. Y.; Greening, G.; Wong, P.; Hoff, B. W.; Gilgenbach, R. M.

    2015-08-01

    The Brillouin flow is the prevalent flow in crossed-field devices. We systematically study its stability in the conventional, planar, and inverted magnetron geometry. To investigate the intrinsic negative mass effect in Brillouin flow, we consider electrostatic modes in a nonrelativistic, smooth bore magnetron. We found that the Brillouin flow in the inverted magnetron is more unstable than that in a planar magnetron, which in turn is more unstable than that in the conventional magnetron. Thus, oscillations in the inverted magnetron may startup faster than the conventional magnetron. This result is consistent with simulations, and with the negative mass property in the inverted magnetron configuration. Inclusion of relativistic effects and electromagnetic effects does not qualitatively change these conclusions.

  11. 8. Inverted siphon structure carrying ditch flow under Willow Creek, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. Inverted siphon structure carrying ditch flow under Willow Creek, looking southwest - Natomas Ditch System, Blue Ravine Segment, Juncture of Blue Ravine & Green Valley Roads, Folsom, Sacramento County, CA

  12. 7. Inverted siphon structure carrying ditch flow under Willow Creek, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. Inverted siphon structure carrying ditch flow under Willow Creek, looking east - Natomas Ditch System, Blue Ravine Segment, Juncture of Blue Ravine & Green Valley Roads, Folsom, Sacramento County, CA

  13. 145. Credit JE. Steel section of Coleman Canal inverted siphon ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    145. Credit JE. Steel section of Coleman Canal inverted siphon #2, crossing Baldwin Creek. (JE, v. 27 1911 p. 413). - Battle Creek Hydroelectric System, Battle Creek & Tributaries, Red Bluff, Tehama County, CA

  14. An inverter/controller subsystem optimized for photovoltaic applications

    NASA Technical Reports Server (NTRS)

    Pickrell, R. L.; Merrill, W. C.; Osullivan, G.

    1978-01-01

    Conversion of solar array dc power to ac power stimulated the specification, design, and simulation testing of an inverter/controller subsystem tailored to the photovoltaic power source characteristics. This paper discusses the optimization of the inverter/controller design as part of an overall Photovoltaic Power System (PPS) designed for maximum energy extraction from the solar array. The special design requirements for the inverter/controller include: (1) a power system controller (PSC) to control continuously the solar array operating point at the maximum power level based on variable solar insolation and cell temperatures; and (2) an inverter designed for high efficiency at rated load and low losses at light loadings to conserve energy. It must be capable of operating connected to the utility line at a level set by an external controller (PSC).

  15. Stability of Brillouin flow in planar, conventional, and inverted magnetrons

    SciTech Connect

    Simon, D. H.; Lau, Y. Y.; Greening, G.; Wong, P.; Gilgenbach, R. M.; Hoff, B. W.

    2015-08-15

    The Brillouin flow is the prevalent flow in crossed-field devices. We systematically study its stability in the conventional, planar, and inverted magnetron geometry. To investigate the intrinsic negative mass effect in Brillouin flow, we consider electrostatic modes in a nonrelativistic, smooth bore magnetron. We found that the Brillouin flow in the inverted magnetron is more unstable than that in a planar magnetron, which in turn is more unstable than that in the conventional magnetron. Thus, oscillations in the inverted magnetron may startup faster than the conventional magnetron. This result is consistent with simulations, and with the negative mass property in the inverted magnetron configuration. Inclusion of relativistic effects and electromagnetic effects does not qualitatively change these conclusions.

  16. 13. WESTERN VIEW OF INVERTED BASIC OXYGEN FURNACE No. 2 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. WESTERN VIEW OF INVERTED BASIC OXYGEN FURNACE No. 2 ON THE OPERATING FLOOR OF THE FURNACE AISLE IN THE BOP SHOP. - U.S. Steel Duquesne Works, Basic Oxygen Steelmaking Plant, Along Monongahela River, Duquesne, Allegheny County, PA

  17. 15. WESTERN VIEW OF INVERTED BASIC OXYGEN FURNACE No. 2 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. WESTERN VIEW OF INVERTED BASIC OXYGEN FURNACE No. 2 ON THE GROUND FLOOR OF THE FURNACE AISLE IN THE BOP SHOP. - U.S. Steel Duquesne Works, Basic Oxygen Steelmaking Plant, Along Monongahela River, Duquesne, Allegheny County, PA

  18. 14. WESTERN VIEW OF INVERTED BASIC OXYGEN FURNACE No. 1 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. WESTERN VIEW OF INVERTED BASIC OXYGEN FURNACE No. 1 ON THE OPERATING FLOOR OF THE FURNACE AISLE IN THE BOP SHOP. - U.S. Steel Duquesne Works, Basic Oxygen Steelmaking Plant, Along Monongahela River, Duquesne, Allegheny County, PA

  19. The Generation of an Organic Inverted Chemical Garden.

    PubMed

    Pampalakis, Georgios

    2016-05-10

    A chemical garden based on iron salt that grows in organic solvents and ions is demonstrated for the first time. This prototype chemical garden develops in an inverted orientation, thus providing evidence that downward growth is feasible. PMID:26995656

  20. Performance model for grid-connected photovoltaic inverters.

    SciTech Connect

    Boyson, William Earl; Galbraith, Gary M.; King, David L.; Gonzalez, Sigifredo

    2007-09-01

    This document provides an empirically based performance model for grid-connected photovoltaic inverters used for system performance (energy) modeling and for continuous monitoring of inverter performance during system operation. The versatility and accuracy of the model were validated for a variety of both residential and commercial size inverters. Default parameters for the model can be obtained from manufacturers specification sheets, and the accuracy of the model can be further refined using measurements from either well-instrumented field measurements in operational systems or using detailed measurements from a recognized testing laboratory. An initial database of inverter performance parameters was developed based on measurements conducted at Sandia National Laboratories and at laboratories supporting the solar programs of the California Energy Commission.

  1. Studies of the Inverted Meniscus Deposition of Silicon on Ceramic

    NASA Technical Reports Server (NTRS)

    Zook, J. D.; Grung, B.; Schuldt, S. B.; Schmit, F. M.; Heaps, J. D.

    1983-01-01

    Controlled temperature profiles essential to production of solar cells. Studies of inverted meniscus process for depositing silicon coatings on ceramic substrates described in new report. When fully developed, processed used to manufacture low-cost solar photovoltaic cells.

  2. 2. DETAIL OF INVERTED MINE CARS, LOOKING SOUTHWEST; NOTE SHORT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. DETAIL OF INVERTED MINE CARS, LOOKING SOUTHWEST; NOTE SHORT WHEEL BASE NEEDED FOR DUMPING CONTENTS - Nuttallburg Mine Complex, Main Mine, North side of New River, 2.7 miles upstream from Fayette Landing, Lookout, Fayette County, WV

  3. Transient effects in application of PWM inverters to induction motors

    SciTech Connect

    Persson, E. )

    1992-10-01

    Standard squirrel cage induction (SCI) motors are subjected to nonsinusoidal waveshapes when supplied form adjustable-frequency inverters. In addition to causing increased heating, these wave patterns can be destructive to the insulation. In particular, pulse width modulated (PWM) inverter output amplitudes and rise times are investigated. Motor insulation capabilities are discussed. In this paper, voltage reflections are simulated for various cable lengths and rise times and are presented graphically. Simulations confirm potential problems with long cables and short rise times.

  4. SEPP-ZVS High Frequency Inverter Incorporating Auxiliary Switch

    NASA Astrophysics Data System (ADS)

    Ogiwara, Hiroyuki; Itoi, Misao; Nakaoka, Mutsuo

    This paper presents a novel circuit topology to attain ZVS operation of a high frequency inverter over a wide range output power regulation using a PWM control technique by connecting an auxiliary switch to the conventional single ended push-pull (SEPP) ZVS high frequency inverter. A switching current is injected into the main switches via the auxiliary switch only during the short period between its turn-on and off times to supply a current required for its ZVS operation.

  5. High-performance inverters for grid-connected PV applications

    SciTech Connect

    Heide, F.J. ter; Wanner, J.

    1994-12-31

    In a few years time Mastervolt has become one of the leading European manufacturers of stand-alone inverters for marine and mobile applications. The application of photovoltaics in this area is well on its way. Based on this experience the development of grid-connected inverters evolved naturally within the context of the effort for development of grid-connected photovoltaic systems in the Netherlands. Technical description and applications are given for the Sunmaster 1800 and 300.

  6. Protein Repeats from First Principles.

    PubMed

    Turjanski, Pablo; Parra, R Gonzalo; Espada, Rocío; Becher, Verónica; Ferreiro, Diego U

    2016-01-01

    Some natural proteins display recurrent structural patterns. Despite being highly similar at the tertiary structure level, repeating patterns within a single repeat protein can be extremely variable at the sequence level. We use a mathematical definition of a repetition and investigate the occurrences of these in sequences of different protein families. We found that long stretches of perfect repetitions are infrequent in individual natural proteins, even for those which are known to fold into structures of recurrent structural motifs. We found that natural repeat proteins are indeed repetitive in their families, exhibiting abundant stretches of 6 amino acids or longer that are perfect repetitions in the reference family. We provide a systematic quantification for this repetitiveness. We show that this form of repetitiveness is not exclusive of repeat proteins, but also occurs in globular domains. A by-product of this work is a fast quantification of the likelihood of a protein to belong to a family. PMID:27044676

  7. Protein Repeats from First Principles

    PubMed Central

    Turjanski, Pablo; Parra, R. Gonzalo; Espada, Rocío; Becher, Verónica; Ferreiro, Diego U.

    2016-01-01

    Some natural proteins display recurrent structural patterns. Despite being highly similar at the tertiary structure level, repeating patterns within a single repeat protein can be extremely variable at the sequence level. We use a mathematical definition of a repetition and investigate the occurrences of these in sequences of different protein families. We found that long stretches of perfect repetitions are infrequent in individual natural proteins, even for those which are known to fold into structures of recurrent structural motifs. We found that natural repeat proteins are indeed repetitive in their families, exhibiting abundant stretches of 6 amino acids or longer that are perfect repetitions in the reference family. We provide a systematic quantification for this repetitiveness. We show that this form of repetitiveness is not exclusive of repeat proteins, but also occurs in globular domains. A by-product of this work is a fast quantification of the likelihood of a protein to belong to a family. PMID:27044676

  8. Protein Repeats from First Principles

    NASA Astrophysics Data System (ADS)

    Turjanski, Pablo; Parra, R. Gonzalo; Espada, Rocío; Becher, Verónica; Ferreiro, Diego U.

    2016-04-01

    Some natural proteins display recurrent structural patterns. Despite being highly similar at the tertiary structure level, repeating patterns within a single repeat protein can be extremely variable at the sequence level. We use a mathematical definition of a repetition and investigate the occurrences of these in sequences of different protein families. We found that long stretches of perfect repetitions are infrequent in individual natural proteins, even for those which are known to fold into structures of recurrent structural motifs. We found that natural repeat proteins are indeed repetitive in their families, exhibiting abundant stretches of 6 amino acids or longer that are perfect repetitions in the reference family. We provide a systematic quantification for this repetitiveness. We show that this form of repetitiveness is not exclusive of repeat proteins, but also occurs in globular domains. A by-product of this work is a fast quantification of the likelihood of a protein to belong to a family.

  9. Distortion and regulation characterization of a Mapham inverter

    NASA Technical Reports Server (NTRS)

    Sundberg, Richard C.; Brush, Andrew S.; Button, Robert M.; Patterson, Alexander G.

    1989-01-01

    Output-voltage total harmonic distortion (THD) of a 20-kHz, 6-kVA Mapham resonant inverter is characterized as a function of its switching-to-resonant frequency ratio, f(s)/f(r), using the EASY5 Engineering Analysis System. EASY5 circuit simulation results are compared with hardware test results to verify the accuracy of the simulations. The effects of load on the THD versus f(s)/f(r) is investigated for resistive, leading, and lagging power factor load impedances. The effect of the series output capacitor on the Mapham inverter output-voltage distortion and inherent load regulation is characterized under loads of various power factors and magnitudes. An optimum series capacitor value which improves the inherent load regulation to better than 3 percent is identified. The optimum series capacitor value is different from the value predicted from a modeled frequency domain analysis. An explanation is proposed which takes into account the conduction overlap in the inductor pairs during steady-state inverter operation, which decreases the effective inductance of a Mapham inverter. A fault protection and current limit method is discussed which allows the Mapham inverter to operate into a short circuit, even when the inverter resonant circuit becomes overdamped.

  10. Distortion and regulation characterization of a Mapham inverter

    NASA Technical Reports Server (NTRS)

    Sundberg, Richard C.; Brush, Andrew S.; Button, Robert M.; Patterson, Alexander G.

    1989-01-01

    Output voltage Total Harmonic Distortion (THD) of a 20kHz, 6kVA Mapham resonant inverter is characterized as a function of its switching-to-resonant frequency ratio, f sub s/f sub r, using the EASY5 engineering analysis system. EASY5 circuit simulation results are compared with hardware test results to verify the accuracy of the simulations. The effects of load on the THD versus f sub s/f sub r ratio is investigated for resistive, leading, and lagging power factor load impedances. The effect of the series output capacitor on the Mapham inverter output voltage distortion and inherent load regulation is characterized under loads of various power factors and magnitudes. An optimum series capacitor value which improves the inherent load regulation to better than 3 percent is identified. The optimum series capacitor value is different than the value predicted from a modeled frequency domain analysis. An explanation is proposed which takes into account the conduction overlap in the inductor pairs during steady-state inverter operation, which decreases the effective inductance of a Mapham inverter. A fault protection and current limit method is discussed which allows the Mapham inverter to operate into a short circuit, even when the inverter resonant circuit becomes overdamped.

  11. Management and treatment of sinonasal inverted papilloma

    PubMed Central

    Ungari, Claudio; Riccardi, Emiliano; Reale, Gabriele; Agrillo, Alessandro; Rinna, Claudio; Mitro, Valeria; Filiaci, Fabio

    2015-01-01

    Summary Aims The aim of this paper is to describe the surgical experience of 35 patients with Inverted Papilloma (IP) of paranasal sinuses and its recurrence rate after a year of follow-up. Materials A retrospective chart review was performed on patients presenting with IP of paranasal sinuses. Thirty-five patients comprised the focus of this study. For all patients was performed a pre-surgery TC, and for more 5 patients it was necessary to perform a Magnetic Resonance (MR) with gadolinium. Results Among 35 patients selected, 18 patients underwent to open surgery, 4 patients had a combined approach with endoscopy and open surgery, while 13 patients were managed only with an endoscopic approach, with a minimum of 1 year of follow-up. Our results highlighted that the global percentage of success 12 months after the treatment was 93% and it not vary according to the tipology of the approach used if a radical excision of the lesion is achieved. More in depth, among 35 cases, only 2 patients were found to have recurrences and were treated with coronal and endoscopic approach. Conclusion It is fundamental to underline that surgery must be carried on in a radical manner to treat these tend to recur. A complete removal of the lesion and bone peripheral border filing are essential to perform a correct and definitive treatment. Also, endoscopic approach can be taken into account when tumors are localized median to a sagittal plan crossing the orbit median wall and when they did not massively compromised paranasal sinus walls. PMID:26941894

  12. Frequency domain model for analysis of paralleled, series-output-connected Mapham inverters

    NASA Technical Reports Server (NTRS)

    Brush, Andrew S.; Sundberg, Richard C.; Button, Robert M.

    1989-01-01

    The Mapham resonant inverter is characterized as a two-port network driven by a selected periodic voltage. The two-port model is then used to model a pair of Mapham inverters connected in series and employing phasor voltage regulation. It is shown that the model is useful for predicting power output in paralleled inverter units, and for predicting harmonic current output of inverter pairs, using standard power flow techniques. Some sample results are compared to data obtained from testing hardware inverters.

  13. Frequency domain model for analysis of paralleled, series-output-connected Mapham inverters

    NASA Technical Reports Server (NTRS)

    Brush, Andrew S.; Sundberg, Richard C.; Button, Robert M.

    1989-01-01

    The Mapham resonant inverter is characterized as a two-port network driven by a selected periodic voltage. The two-port model is then used to model a pair of Mapham inverters connected in series and employing phasor voltage regulation. It is shown that the model is useful for predicting power output in paralleled inverter units, and for predicting harmonic current output of inverter pairs, using standard power flow techniques. Some examples are compared to data obtained from testing hardware inverters.

  14. Breaking Barriers to Low-Cost Modular Inverter Production & Use

    SciTech Connect

    Bogdan Borowy; Leo Casey; Jerry Foshage; Steve Nichols; Jim Perkinson

    2005-05-31

    The goal of this cost share contract is to advance key technologies to reduce size, weight and cost while enhancing performance and reliability of Modular Inverter Product for Distributed Energy Resources (DER). Efforts address technology development to meet technical needs of DER market protection, isolation, reliability, and quality. Program activities build on SatCon Technology Corporation inverter experience (e.g., AIPM, Starsine, PowerGate) for Photovoltaic, Fuel Cell, Energy Storage applications. Efforts focused four technical areas, Capacitors, Cooling, Voltage Sensing and Control of Parallel Inverters. Capacitor efforts developed a hybrid capacitor approach for conditioning SatCon's AIPM unit supply voltages by incorporating several types and sizes to store energy and filter at high, medium and low frequencies while minimizing parasitics (ESR and ESL). Cooling efforts converted the liquid cooled AIPM module to an air-cooled unit using augmented fin, impingement flow cooling. Voltage sensing efforts successfully modified the existing AIPM sensor board to allow several, application dependent configurations and enabling voltage sensor galvanic isolation. Parallel inverter control efforts realized a reliable technique to control individual inverters, connected in a parallel configuration, without a communication link. Individual inverter currents, AC and DC, were balanced in the paralleled modules by introducing a delay to the individual PWM gate pulses. The load current sharing is robust and independent of load types (i.e., linear and nonlinear, resistive and/or inductive). It is a simple yet powerful method for paralleling both individual devices dramatically improves reliability and fault tolerance of parallel inverter power systems. A patent application has been made based on this control technology.

  15. Limitations on quantum key repeaters.

    PubMed

    Bäuml, Stefan; Christandl, Matthias; Horodecki, Karol; Winter, Andreas

    2015-01-01

    A major application of quantum communication is the distribution of entangled particles for use in quantum key distribution. Owing to noise in the communication line, quantum key distribution is, in practice, limited to a distance of a few hundred kilometres, and can only be extended to longer distances by use of a quantum repeater, a device that performs entanglement distillation and quantum teleportation. The existence of noisy entangled states that are undistillable but nevertheless useful for quantum key distribution raises the question of the feasibility of a quantum key repeater, which would work beyond the limits of entanglement distillation, hence possibly tolerating higher noise levels than existing protocols. Here we exhibit fundamental limits on such a device in the form of bounds on the rate at which it may extract secure key. As a consequence, we give examples of states suitable for quantum key distribution but unsuitable for the most general quantum key repeater protocol. PMID:25903096

  16. Hysteresis of magnetostructural transitions: Repeatable and non-repeatable processes

    NASA Astrophysics Data System (ADS)

    Provenzano, Virgil; Della Torre, Edward; Bennett, Lawrence H.; ElBidweihy, Hatem

    2014-02-01

    The Gd5Ge2Si2 alloy and the off-stoichiometric Ni50Mn35In15 Heusler alloy belong to a special class of metallic materials that exhibit first-order magnetostructural transitions near room temperature. The magnetic properties of this class of materials have been extensively studied due to their interesting magnetic behavior and their potential for a number of technological applications such as refrigerants for near-room-temperature magnetic refrigeration. The thermally driven first-order transitions in these materials can be field-induced in the reverse order by applying a strong enough field. The field-induced transitions are typically accompanied by the presence of large magnetic hysteresis, the characteristics of which are a complicated function of temperature, field, and magneto-thermal history. In this study we show that the virgin curve, the major loop, and sequentially measured MH loops are the results of both repeatable and non-repeatable processes, in which the starting magnetostructural state, prior to the cycling of field, plays a major role. Using the Gd5Ge2Si2 and Ni50Mn35In15 alloys, as model materials, we show that a starting single phase state results in fully repeatable processes and large magnetic hysteresis, whereas a mixed phase starting state results in non-repeatable processes and smaller hysteresis.

  17. Repeating seismic events in China.

    PubMed

    Schaff, David P; Richards, Paul G

    2004-02-20

    About 10% of seismic events in and near China from 1985 to 2000 were repeating events not more than about 1 kilometer from each other. We cross-correlated seismograms from approximately 14,000 earthquakes and explosions and measured relative arrival times to approximately 0.01 second, enabling lateral location precision of about 100 to 300 meters. Such precision is important for seismic hazard studies, earthquake physics, and nuclear test ban verification. Recognition and measurement of repeating signals in archived data and the resulting improvement in location specificity quantifies the inaccuracy of current procedures for picking onset times and locating events. PMID:14976310

  18. Pure laparoscopic hepatectomy as repeat surgery and repeat hepatectomy

    PubMed Central

    Isetani, Masashi; Morise, Zenichi; Kawabe, Norihiko; Tomishige, Hirokazu; Nagata, Hidetoshi; Kawase, Jin; Arakawa, Satoshi

    2015-01-01

    AIM: To assess clinical outcomes of laparoscopic hepatectomy (LH) in patients with a history of upper abdominal surgery and repeat hepatectomy. METHODS: This study compared the perioperative courses of patients receiving LH at our institution that had or had not previously undergone upper abdominal surgery. Of the 80 patients who underwent LH, 22 had prior abdominal surgeries, including hepatectomy (n = 12), pancreatectomy (n = 3), cholecystectomy and common bile duct excision (n = 1), splenectomy (n = 1), total gastrectomy (n = 1), colectomy with the involvement of transverse colon (n = 3), and extended hysterectomy with extensive lymph-node dissection up to the upper abdomen (n = 1). Clinical indicators including operating time, blood loss, hospital stay, and morbidity were compared among the groups. RESULTS: Eighteen of the 22 patients who had undergone previous surgery had severe adhesions in the area around the liver. However, there were no conversions to laparotomy in this group. In the 58 patients without a history of upper abdominal surgery, the median operative time was 301 min and blood loss was 150 mL. In patients with upper abdominal surgical history or repeat hepatectomy, the operative times were 351 and 301 min, and blood loss was 100 and 50 mL, respectively. The median postoperative stay was 17, 13 and 12 d for patients with no history of upper abdominal surgery, patients with a history, and patients with repeat hepatectomy, respectively. There were five cases with complications in the group with no surgical history, compared to only one case in the group with a prior history. There were no statistically significant differences in the perioperative results between the groups with and without upper abdominal surgical history, or with repeat hepatectomy. CONCLUSION: LH is feasible and safe in patients with a history of upper abdominal surgery or repeat hepatectomy. PMID:25624731

  19. Efficiency consideration of DC link soft-switching inverters for motor drive applications

    SciTech Connect

    Lai, J.S.; Young, R.W.; McKeever, J.W.

    1994-12-31

    This paper critically evaluates efficiency of soft switching inverters including an actively clamped resonant dc link inverter and a clamped-mode resonant pole inverter. An analytical approach to evaluating efficiency of the clamped-mode soft switching inverter has been developed. The evaluation results are compared with that of the standard pulse-width-modulation (PWM) inverter. A 50-kW induction motor is used as the variable load, and the inverter efficiency is evaluated under different speed and torque conditions. The clamped-mode soft-switching inverter, although eliminating the switching loss, shows poor efficiency over the entire load range. Under low load conditions, the efficiency profile is even worse. The actively clamped resonant dc link inverter shows highest efficiency over the entire speed and torque range. However, its energy saving over the standard PWM inverter is marginal under full load or high speed conditions.

  20. The pathology of urinary bladder lesions with an inverted growth pattern.

    PubMed

    Guo, Aitao; Liu, Aijun; Teng, Xiaodong

    2016-02-01

    Inverted lesions in the urinary bladder have been the source of some difficulty in urological pathology. The two common ones are von Brunn's nests and cystitis cystic/cystitis glandularis, which are considered normal variants of urothelium. Apart from them, a number of other rare urothelial lesions with inverted growth pattern occur in the urinary bladder. Some of them are only reactive conditions, just as pseudocarcinomatous hyperplasia. Some are benign tumors, namely inverted papilloma. Whereas others are malignant neoplasms, including inverted papillary urothelial neoplasm of low malignant potential (PUNLMP), non-invasive inverted papillary urothelial carcinoma (low-grade and high-grade), and invasive urothelial carcinoma (inverted, nested and big nested variants). Because of the overlapping morphological features of all the inverted lesions mentioned above, even between high-grade invasive carcinoma and pseudocarcinomatous hyperplasia which are only a kind of reactive conditions, it is very important for the surgical pathologist to recognize and be familiar with these inverted lesions in urinary bladder. In this article, we review these spectrums of inverted lesions of the urinary bladder. Emphasis is placed on histogenesis, morphology, differential diagnosis of these lesions, and the pathologic grading of the non-invasive inverted neoplasms, such as inverted papilloma, inverted PUNLMP, non-invasive inverted papillary urothelial carcinoma with low-grade, and non-invasive inverted papillary urothelial carcinoma with high-grade. PMID:27041933

  1. The pathology of urinary bladder lesions with an inverted growth pattern

    PubMed Central

    Liu, Aijun; Teng, Xiaodong

    2016-01-01

    Inverted lesions in the urinary bladder have been the source of some difficulty in urological pathology. The two common ones are von Brunn’s nests and cystitis cystic/cystitis glandularis, which are considered normal variants of urothelium. Apart from them, a number of other rare urothelial lesions with inverted growth pattern occur in the urinary bladder. Some of them are only reactive conditions, just as pseudocarcinomatous hyperplasia. Some are benign tumors, namely inverted papilloma. Whereas others are malignant neoplasms, including inverted papillary urothelial neoplasm of low malignant potential (PUNLMP), non-invasive inverted papillary urothelial carcinoma (low-grade and high-grade), and invasive urothelial carcinoma (inverted, nested and big nested variants). Because of the overlapping morphological features of all the inverted lesions mentioned above, even between high-grade invasive carcinoma and pseudocarcinomatous hyperplasia which are only a kind of reactive conditions, it is very important for the surgical pathologist to recognize and be familiar with these inverted lesions in urinary bladder. In this article, we review these spectrums of inverted lesions of the urinary bladder. Emphasis is placed on histogenesis, morphology, differential diagnosis of these lesions, and the pathologic grading of the non-invasive inverted neoplasms, such as inverted papilloma, inverted PUNLMP, non-invasive inverted papillary urothelial carcinoma with low-grade, and non-invasive inverted papillary urothelial carcinoma with high-grade. PMID:27041933

  2. Dynamics of liquid sloshing in upright and inverted bladdered tanks

    NASA Astrophysics Data System (ADS)

    Dodge, F. T.; Kana, D. D.

    A system identification methodology was used to examine the dynamics of liquid sloshing in the upright and inverted bladdered hydrazine tanks of the Tracking and Data Relay Satellite, (TDRS) and to evaluate the effects of bladder stiffness on the sloshing parameters. Mechanical models of the two systems were developed using the numerical values derived from static stability tests and from slosh frequency response tests of a full-size model tank fitted with a prototype bladder. For the upright tank (liquid below the bladder) a modified conventional pendulum was used. In the inverted tank (liquid above the bladder) where sloshing is unconventional due to the highly nonsymmetrical orientation of the liquid held by the bladder, a mechanical model using an inverted pendulum which is able to undergo small oscillations as well as large reorientations was necessary. Both thrusting and low-gravity conditions are considered.

  3. Dynamics of liquid sloshing in upright and inverted bladdered tanks

    NASA Technical Reports Server (NTRS)

    Dodge, F. T.; Kana, D. D.

    1985-01-01

    A system identification methodology was used to examine the dynamics of liquid sloshing in the upright and inverted bladdered hydrazine tanks of the Tracking and Data Relay Satellite, (TDRS) and to evaluate the effects of bladder stiffness on the sloshing parameters. Mechanical models of the two systems were developed using the numerical values derived from static stability tests and from slosh frequency response tests of a full-size model tank fitted with a prototype bladder. For the upright tank (liquid below the bladder) a modified conventional pendulum was used. In the inverted tank (liquid above the bladder) where sloshing is unconventional due to the highly nonsymmetrical orientation of the liquid held by the bladder, a mechanical model using an inverted pendulum which is able to undergo small oscillations as well as large reorientations was necessary. Both thrusting and low-gravity conditions are considered.

  4. Three-phase multilevel solar inverter for motor drive system

    NASA Astrophysics Data System (ADS)

    Bhasagare, Mayuresh P.

    This thesis deals with three phase inverters and the different control strategies that can be associated with an inverter being used together. The first part of this thesis discusses the present research in the fields of PV panels, motor drive systems and three phase inverters along with their control. This control includes various strategies like MPPT, Volts-Hertz and modulation index compensation. Incorporating these techniques together is the goal of this thesis. A new topology for operating an open end motor drive system has also been discusses, where a boost converter and a flyback converter have been used in cascade to run a three phase motor. The main advantage of this is increasing the number of levels and improving the quality of the output voltage, not to mention a few other benefits of having the proposed circuit. A new algorithm has also been designed for starting and stopping the motor, which controls the current drawn from the power source during starting.

  5. Suspended Patch Antenna Array With Electromagnetically Coupled Inverted Microstrip Feed

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.

    2000-01-01

    The paper demonstrates a four-element suspended patch antenna array, with a parasitic patch layer and an electromagnetically coupled inverted microstrip feed, for linear polarization at K-Band frequencies. This antenna has the following advantages over conventional microstrip antennas: First, the inverted microstrip has lower attenuation than conventional microstrip; hence, conductor loss associated with the antenna corporate feed is lower resulting in higher gain and efficiency. Second, conventional proximity coupled patch antennas require a substrate for the feed and a superstrate for the patch. However, the inverted microstrip fed patch antenna makes use of a single substrate, and hence, is lightweight and low cost. Third, electromagnetic coupling results in wider bandwidth. Details regarding the design and fabrication will be presented as well as measured results including return loss, radiation patterns and cross-polarization levels.

  6. Do Twelfths Terminate or Repeat?

    ERIC Educational Resources Information Center

    Ambrose, Rebecca; Burnison, Erica

    2015-01-01

    When finding the decimal equivalent of a fraction with 12 in the denominator, will it terminate or repeat? This question came from a seventh grader in author Erica Burnison's class as the student was pondering a poster generated by one of her classmates. Not only was the question intriguing, but it also affirmed the belief in the power of…

  7. Pentapeptide Repeat Proteins and Cyanobacteria

    SciTech Connect

    Buchko, Garry W.

    2009-10-16

    Cyanobacteria are unique in many ways and one unusual feature is the presence of a suite of proteins that contain at least one domain with a minimum of eight tandem repeated five-residues (Rfr) of the general consensus sequence A[N/D]LXX. The function of such pentapeptide repeat proteins (PRPs) are still unknown, however, their prevalence in cyanobacteria suggests that they may play some role in the unique biological activities of cyanobacteria. As part of an inter-disciplinary Membrane Biology Grand Challenge at the Environmental Molecular Sciences Laboratory (Pacific Northwest National Laboratory) and Washington University in St. Louis, the genome of Cyanothece 51142 was sequenced and its molecular biology studied with relation to circadian rhythms. The genome of Cyanothece encodes for 35 proteins that contain at least one PRP domain. These proteins range in size from 105 (Cce_3102) to 930 (Cce_2929) kDa with the PRP domains ranging in predicted size from 12 (Cce_1545) to 62 (cce_3979) tandem pentapeptide repeats. Transcriptomic studies with 29 out of the 35 genes showed that at least three of the PRPs in Cyanothece 51142 (cce_0029, cce_3083, and cce_3272) oscillated with repeated periods of light and dark, further supporting a biological function for PRPs. Using X-ray diffraction crystallography, the structure for two pentapeptide repeat proteins from Cyanothece 51142 were determined, cce_1272 (aka Rfr32) and cce_4529 (aka Rfr23). Analysis of their molecular structures suggests that all PRP may share the same structural motif, a novel type of right-handed quadrilateral β-helix, or Rfr-fold, reminiscent of a square tower with four distinct faces. Each pentapeptide repeat occupies one face of the Rfr-fold with four consecutive pentapeptide repeats completing a coil that, in turn, stack upon each other to form “protein skyscrapers”. Details of the structural features of the Rfr-fold are reviewed here together with a discussion for the possible role of end

  8. The Influence of Primary and Secondary DNA Structure in Deletion and Duplication between Direct Repeats in Escherichia Coli

    PubMed Central

    Trinh, T. Q.; Sinden, R. R.

    1993-01-01

    We describe a system to measure the frequency of both deletions and duplications between direct repeats. Short 17- and 18-bp palindromic and nonpalindromic DNA sequences were cloned into the EcoRI site within the chloramphenicol acetyltransferase gene of plasmids pBR325 and pJT7. This creates an insert between direct repeated EcoRI sites and results in a chloramphenicol-sensitive phenotype. Selection for chloramphenicol resistance was utilized to select chloramphenicol resistant revertants that included those with precise deletion of the insert from plasmid pBR325 and duplication of the insert in plasmid pJT7. The frequency of deletion or duplication varied more than 500-fold depending on the sequence of the short sequence inserted into the EcoRI site. For the nonpalindromic inserts, multiple internal direct repeats and the length of the direct repeats appear to influence the frequency of deletion. Certain palindromic DNA sequences with the potential to form DNA hairpin structures that might stabilize the misalignment of direct repeats had a high frequency of deletion. Other DNA sequences with the potential to form structures that might destabilize misalignment of direct repeats had a very low frequency of deletion. Duplication mutations occurred at the highest frequency when the DNA between the direct repeats contained no direct or inverted repeats. The presence of inverted repeats dramatically reduced the frequency of duplications. The results support the slippage-misalignment model, suggesting that misalignment occurring during DNA replication leads to deletion and duplication mutations. The results also support the idea that the formation of DNA secondary structures during DNA replication can facilitate and direct specific mutagenic events. PMID:8325478

  9. Transparent film with inverted conical microholes array for reflection enhancement

    NASA Astrophysics Data System (ADS)

    Lei, Biao; Liu, Hongzhong; Jiang, Weitao; Chen, Bangdao; Shi, Yongsheng; Yin, Lei; Liu, Xiaokang

    2016-04-01

    PDMS has been widely utilized for microfluidic chips and microchannel detections, as its good optical properties are the prerequisite to achieve accurate and efficient detection. However, it is difficult to obtain effective information for opaque liquids. With the development of microchannel detection for wider fields, it is imperative to obtain more comprehensive information of the observed objects by integrating high transmission with enhanced reflection. This article investigates reflection enhancement by Polydimethylsiloxane (PDMS) film with inverted conical microholes array. PDMS film with inverted conical microholes array is fabricated by replication from the silicon mold with inverted microcones array which is prepared by Inductively Coupled Plasma (ICP) etch tool. The monolayer PDMS film with inverted conical microholes array shows a two-fold effectively increase in reflection, approximately up to 15%, at a broad wavelength range of 637-1131 nm and 1214-1350 nm, compared with bare PDMS film. In addition, the reflection can be further enhanced by multilayered lamination of PDMS film with inverted conical microholes array, and the enhancement is also dependent on the lamination way, i.e., for bilayer laminations, the maximum reflection enhancement occurs when with face-to-back lamination, and 32.79% larger than that with back-to-face lamination. From the experiments, the maximum reflectivity of 8-layered PDMS films can obtain 64.4% while the maximum reflectivity of monolayer PDMS film barely has 17.5%. The transparent film with inverted conical microholes array for reflection enhancement may find a variety of applications in optical devices, microchips, and energy conservation technologies etc.

  10. Inverted organic photovoltaic device with a new electron transport layer

    PubMed Central

    2014-01-01

    We demonstrate that there is a new solution-processed electron transport layer, lithium-doped zinc oxide (LZO), with high-performance inverted organic photovoltaic device. The device exhibits a fill factor of 68.58%, an open circuit voltage of 0.86 V, a short-circuit current density of −9.35 cm/mA2 along with 5.49% power conversion efficiency. In addition, we studied the performance of blend ratio dependence on inverted organic photovoltaics. Our device also demonstrates a long stability shelf life over 4 weeks in air. PMID:24674457

  11. Toroidal transformer design program with application to inverter circuitry

    NASA Technical Reports Server (NTRS)

    Dayton, J. A., Jr.

    1972-01-01

    Estimates of temperature, weight, efficiency, regulation, and final dimensions are included in the output of the computer program for the design of transformers for use in the basic parallel inverter. The program, written in FORTRAN 4, selects a tape wound toroidal magnetic core and, taking temperature, materials, core geometry, skin depth, and ohmic losses into account, chooses the appropriate wire sizes and number of turns for the center tapped primary and single secondary coils. Using the program, 2- and 4-kilovolt-ampere transformers are designed for frequencies from 200 to 3200 Hz and the efficiency of a basic transistor inverter is estimated.

  12. Design and field performance of the KENETECH photovoltaic inverter system

    SciTech Connect

    Behnke, M.R.

    1995-11-01

    KENETECH Windpower has recently adapted the power conversion technology developed for the company`s variable speed wind turbine to grid-connected photovoltaic applications. KENETECH PV inverter systems are now in successful operation at the Sacramento Municipal Utility District`s (SMUD) Hedge Substation and the PVUSA-Davis site, with additional systems scheduled to be placed into service by the end of 1995 at SMUD, the New York Power Authority, Xerox Corporation`s Clean Air Now project, and the Georgia Tech Aquatic Center. The features of the inverter are described.

  13. Interaction between two side-by-side inverted flags

    NASA Astrophysics Data System (ADS)

    Huertas-Cerdeira, Cecilia; Fan, Boyu; Barizien, Antoine; Gharib, Morteza

    2015-11-01

    The inverted flag instability occurs when an elastic plate that is free at its leading edge and clamped at its trailing edge is subjected to an axial wind. The oscillating motion that follows has received recent attention. However, previous studies have focused on the dynamics of a single flag even though these are rarely found isolated in natural phenomena, such as the fluttering of leaves in the wind. The interaction between two side-by-side inverted flags has been investigated, analyzing the effects of the distance between flags and the wind speed. Both in-phase and anti-phase coupling have been observed for different ranges of these parameters.

  14. Inverter power module with distributed support for direct substrate cooling

    DOEpatents

    Miller, David Harold; Korich, Mark D.; Ward, Terence G.; Mann, Brooks S.

    2012-08-21

    Systems and/or methods are provided for an inverter power module with distributed support for direct substrate cooling. An inverter module comprises a power electronic substrate. A first support frame is adapted to house the power electronic substrate and has a first region adapted to allow direct cooling of the power electronic substrate. A gasket is interposed between the power electronic substrate and the first support frame. The gasket is configured to provide a seal between the first region and the power electronic substrate. A second support frame is adapted to house the power electronic substrate and joined to the first support frame to form the seal.

  15. Addressable Inverter Matrix Tests Integrated-Circuit Wafer

    NASA Technical Reports Server (NTRS)

    Buehler, Martin G.

    1988-01-01

    Addressing elements indirectly through shift register reduces number of test probes. With aid of new technique, complex test structure on silicon wafer tested with relatively small number of test probes. Conserves silicon area by reduction of area devoted to pads. Allows thorough evaluation of test structure characteristics and of manufacturing process parameters. Test structure consists of shift register and matrix of inverter/transmission-gate cells connected to two-by-ten array of probe pads. Entire pattern contained in square area having only 1.6-millimeter sides. Shift register is conventional static CMOS device using inverters and transmission gates in master/slave D flip-flop configuration.

  16. Inverting hydrolases and their use in enantioconvergent biotransformations

    PubMed Central

    Schober, Markus; Faber, Kurt

    2013-01-01

    Owing to the more abundant occurrence of racemic compounds compared to prochiral or meso forms, most enantiomerically pure products are obtained via racemate resolution. This review summarizes (chemo)enzymatic enantioconvergent processes based on the use of hydrolytic enzymes, which are able to invert a stereocenter during catalysis that can overcome the 50%-yield limitation of kinetic resolution. Recent developments are presented in the fields of inverting or retaining sulfatases, epoxide hydrolases and dehalogenases, which allow the production of secondary alcohols or vicinal diols at a 100% theoretical yield from a racemate via enantioconvergent processes. PMID:23809848

  17. DNA sequence analysis of a 5.27-kb direct repeat occurring adjacent to the regions of S-episome homology in maize mitochondria.

    PubMed Central

    Houchins, J P; Ginsburg, H; Rohrbaugh, M; Dale, R M; Schardl, C L; Hodge, T P; Lonsdale, D M

    1986-01-01

    The DNA sequence of the 5270-bp repeated DNA element from the mitochondrial genome of the fertile cytoplasm of maize has been determined. The repeat is a major site of recombination within the mitochondrial genome and sequences related to the R1(S1) and R2(S2) linear episomes reside immediately adjacent to the repeat. The terminal inverted repeats of the R1 and R2 homologous sequences form one of the two boundaries of the repeat. Frame-shift mutations have introduced 11 translation termination codons into the transcribed S2/R2 URFI gene. The repeated sequence, though recombinantly active, appears to serve no biological function. Images Fig. 7. PMID:3792299

  18. Clustering of mutations within the inverted repeat regions of a serially-passaged attenuated gallid herpesvirus type 2 strain.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Marek’s disease (MD) is the leading cause of losses in chicken production in the world. Over the past 40 years significant progress has been made in the control of MD through the use of vaccines which reduce or delay tumor formation in vaccinated flocks. However, these vaccines fail to induce an imm...

  19. The multicopy appearance of a large inverted duplication and the sequence at the inversion joint suggest a new model for gene amplification.

    PubMed Central

    Hyrien, O; Debatisse, M; Buttin, G; de Saint Vincent, B R

    1988-01-01

    The amplified DNA of HC50474, a Chinese hamster fibroblast cell line selected in three steps for high resistance to coformycin, consists chiefly of 150 copies of a large inverted duplication including the adenylate deaminase gene. Most if not all of these units are more than 2 x 120 kb long. The inverted duplication was first detected in the cells recovered from the second selection step, at the same chromosomal location as the first step amplified units. Its formation and amplification appear to be coupled since the second step cell line already contained 40 copies of this novel structure. Reamplification of the inverted duplication occurred at the third step of selection concomitant with the loss of amplified DNA acquired during the first step. The head-to-head junction has been formed by recombination within a recombinational hotspot described previously [Hyrien, O., Debatisse, M., Buttin, G. and Robert de Saint Vincent, B. (1987) EMBO J., 6, 2401-2408]. Sequences at the joint and in the corresponding wild-type region reveal that the crossover sites, one of which occurs in the putative promoter region of B2 repeat, are located at the top of significant stem-loop structures and that patchy homologies between the parental molecules on one side of the breakpoints allow alignment of these crossover sites. We present a model which explains the formation and amplification of this and other large inverted duplications by errors in DNA replication. Images PMID:3366118

  20. Observations of Soft Gamma Repeaters

    NASA Technical Reports Server (NTRS)

    Kouveliotou, Chryssa

    2004-01-01

    Magnetars (Soft Gamma Repeaters and Anomalous X-ray Pulsars) are a subclass of neutron stars characterized by their recurrent X-ray bursts. While in an active (bursting) state (lasting anywhere between days and years), they are emit&ng hundreds of predominantly soft (kT=30 kev), short (0.1-100 ms long) events. Their quiescent source x-ray light ewes exhibit puhlions rotational period rate changes (spin-down) indicate that their magnetic fields are extremely high, of the order of 10^14- 10^l5 G. Such high B-field objects, dubbed "magnetars", had been predicted to exist in 1992, but the first concrete observational evidence were obtained in 1998 for two of these sources. I will discuss here the history of Soft Gamma Repeaters, and their spectral, timing and flux characteristics both in the persistent and their burst emission.

  1. A repeating fast radio burst

    NASA Astrophysics Data System (ADS)

    Spitler, L. G.; Scholz, P.; Hessels, J. W. T.; Bogdanov, S.; Brazier, A.; Camilo, F.; Chatterjee, S.; Cordes, J. M.; Crawford, F.; Deneva, J.; Ferdman, R. D.; Freire, P. C. C.; Kaspi, V. M.; Lazarus, P.; Lynch, R.; Madsen, E. C.; McLaughlin, M. A.; Patel, C.; Ransom, S. M.; Seymour, A.; Stairs, I. H.; Stappers, B. W.; van Leeuwen, J.; Zhu, W. W.

    2016-03-01

    Fast radio bursts are millisecond-duration astronomical radio pulses of unknown physical origin that appear to come from extragalactic distances. Previous follow-up observations have failed to find additional bursts at the same dispersion measure (that is, the integrated column density of free electrons between source and telescope) and sky position as the original detections. The apparent non-repeating nature of these bursts has led to the suggestion that they originate in cataclysmic events. Here we report observations of ten additional bursts from the direction of the fast radio burst FRB 121102. These bursts have dispersion measures and sky positions consistent with the original burst. This unambiguously identifies FRB 121102 as repeating and demonstrates that its source survives the energetic events that cause the bursts. Additionally, the bursts from FRB 121102 show a wide range of spectral shapes that appear to be predominantly intrinsic to the source and which vary on timescales of minutes or less. Although there may be multiple physical origins for the population of fast radio bursts, these repeat bursts with high dispersion measure and variable spectra specifically seen from the direction of FRB 121102 support an origin in a young, highly magnetized, extragalactic neutron star.

  2. A repeating fast radio burst.

    PubMed

    Spitler, L G; Scholz, P; Hessels, J W T; Bogdanov, S; Brazier, A; Camilo, F; Chatterjee, S; Cordes, J M; Crawford, F; Deneva, J; Ferdman, R D; Freire, P C C; Kaspi, V M; Lazarus, P; Lynch, R; Madsen, E C; McLaughlin, M A; Patel, C; Ransom, S M; Seymour, A; Stairs, I H; Stappers, B W; van Leeuwen, J; Zhu, W W

    2016-03-10

    Fast radio bursts are millisecond-duration astronomical radio pulses of unknown physical origin that appear to come from extragalactic distances. Previous follow-up observations have failed to find additional bursts at the same dispersion measure (that is, the integrated column density of free electrons between source and telescope) and sky position as the original detections. The apparent non-repeating nature of these bursts has led to the suggestion that they originate in cataclysmic events. Here we report observations of ten additional bursts from the direction of the fast radio burst FRB 121102. These bursts have dispersion measures and sky positions consistent with the original burst. This unambiguously identifies FRB 121102 as repeating and demonstrates that its source survives the energetic events that cause the bursts. Additionally, the bursts from FRB 121102 show a wide range of spectral shapes that appear to be predominantly intrinsic to the source and which vary on timescales of minutes or less. Although there may be multiple physical origins for the population of fast radio bursts, these repeat bursts with high dispersion measure and variable spectra specifically seen from the direction of FRB 121102 support an origin in a young, highly magnetized, extragalactic neutron star. PMID:26934226

  3. 8. TEST STAND 15, INVERTED ENGINE FIRING TEST, CIRCA 1963. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. TEST STAND 1-5, INVERTED ENGINE FIRING TEST, CIRCA 1963. Original is a color print. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-5, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

  4. Controlling An Inverter-Driven Three-Phase Motor

    NASA Technical Reports Server (NTRS)

    Dolland, C.

    1984-01-01

    Control system for three-phase permanent-magnet motor driven by linecommutated inverter uses signals generated by integrating back emf of each phase of motor. High-pass filter network eliminates low-frequency components from control loop while maintaining desired power factor.

  5. Review of PV Inverter Technology Cost and Performance Projections

    SciTech Connect

    Navigant Consulting Inc.

    2006-01-01

    The National Renewable Energy Laboratory (NREL) has a major responsibility in the implementation of the U.S. Department of Energy's (DOE's) Solar Energy Technologies Program. Sandia National Laboratories (SNL) has a major role in supporting inverter development, characterization, standards, certifications, and verifications. The Solar Energy Technologies Program recently published a Multiyear Technical Plan, which establishes a goal of reducing the Levelized Energy Cost (LEC) for photovoltaic (PV) systems to $0.06/kWh by 2020. The Multiyear Technical Plan estimates that, in order to meet the PV system goal, PV inverter prices will need to decline to $0.25-0.30 Wp by 2020. DOE determined the need to conduct a rigorous review of the PV Program's technical and economic targets, including the target set for PV inverters. NREL requested that Navigant Consulting Inc.(NCI) conduct a review of historical and projected cost and performance improvements for PV inverters, including identification of critical barriers identified and the approaches government might use to address them.

  6. Learning Under Stress: The Inverted-U-Shape Function Revisited

    ERIC Educational Resources Information Center

    Salehi, Basira; Cordero, M. Isabel; Sandi, Carmen

    2010-01-01

    Although the relationship between stress intensity and memory function is generally believed to follow an inverted-U-shaped curve, strikingly this phenomenon has not been demonstrated under the same experimental conditions. We investigated this phenomenon for rats' performance in a hippocampus-dependent learning task, the radial arm water maze…

  7. Design and material selection for inverter transformer cores

    NASA Technical Reports Server (NTRS)

    Mclyman, W. T.

    1973-01-01

    Report is announced which studied magnetic properties of candidate materials for use in spacecraft transformers, static inverters, converters, and transformer-rectifier power supplies. Included are material characteristics for available alloy compositions in tabular form, including: trade names, saturated flux density, dc coercive force, loop squareness, material density, and watts per pound at 3 KHz.

  8. Processing of Inverted Files in Magnetic Bubble Memories.

    ERIC Educational Resources Information Center

    Zaki, M.; Elboraey, F.

    1985-01-01

    Investigates applicability of inverted file processing in magnetic bubble memories by presenting four magnetic bubble memory models as storage mediums: one based on a major-minor loop configuration; one utilizing a decoder design on a magnetic bubble memory chip; and two based on different structural configurations of the first two. (MBR)

  9. Can Holistic Processing Be Learned for Inverted Faces?

    ERIC Educational Resources Information Center

    Robbins, Rachel; McKone, Elinor

    2003-01-01

    The origin of "special" processing for upright faces has been a matter of ongoing debate. If it is due to generic expertise, as opposed to having some innate component, holistic processing should be learnable for stimuli other than upright faces. Here we assess inverted faces. We trained subjects to discriminate identical twins using up to 1100…

  10. Treatment of inverted nipples using a disposable syringe.

    PubMed

    Kesaree, N; Banapurmath, C R; Banapurmath, S; Shamanur, K

    1993-03-01

    Seven mothers who had inverted nipples were helped to breastfeed their infants with the assistance of a simple device made from a 10 ml disposable syringe. These women were able to successfully breastfeed within one week. On follow-up, these mothers were able to sustain adequate breastfeeding. PMID:8489719

  11. Cascaded H-bridge multilevel inverter for renewable energy generation

    NASA Astrophysics Data System (ADS)

    Pandey, Ravikant; Nath Tripathi, Ravi; Hanamoto, Tsuyoshi

    2016-04-01

    In this paper cascaded H-bridge multilevel inverter (CHBMLI) has been investigated for the application of renewable energy generation. Energy sources like solar, wind, hydro, biomass or combination of these can be manipulated to obtain alternative sources for renewable energy generation. These renewable energy sources have different electrical characteristics like DC or AC level so it is challenging to use generated power by connecting to grid or load directly. The renewable energy source require specific power electronics converter as an interface for conditioning generated power .The multilevel inverter can be utilized for renewable energy sources in two different modes, the power generation mode (stand-alone mode), and compensator mode (statcom). The performance of the multilevel inverter has been compared with two level inverter. In power generation mode CHBMLI supplies the active and reactive power required by the different loads. For operation in compensator mode the indirect current control based on synchronous reference frame theory (SRFT) ensures the grid operating in unity power factor and compensate harmonics and reactive power.

  12. Regenerative Snubber For GTO-Commutated SCR Inverter

    NASA Technical Reports Server (NTRS)

    Rippel, Wally E.; Edwards, Dean B.

    1992-01-01

    Proposed regenerative snubbing circuit substituted for dissipative snubbing circuit in inverter based on silicon controlled rectifiers (SCR's) commutated by gate-turn-off thyristor (GTO). Intended to reduce loss of power that occurs in dissipative snubber. Principal criteria in design: low cost, simplicity, and reliability.

  13. High voltage power supply with modular series resonant inverters

    DOEpatents

    Dreifuerst, Gary R.; Merritt, Bernard T.

    1995-01-01

    A relatively small and compact high voltage, high current power supply for a laser utilizes a plurality of modules containing series resonant half bridge inverters. A pair of reverse conducting thyristors are incorporated in each series resonant inverter module such that the series resonant inverter modules are sequentially activated in phases 360.degree./n apart, where n=number of modules for n>2. Selective activation of the modules allows precise output control reducing ripple and improving efficiency. Each series resonant half bridge inverter module includes a transformer which has a cooling manifold for actively circulating a coolant such as water, to cool the transformer core as well as selected circuit elements. Conductors connecting and forming various circuit components comprise hollow, electrically conductive tubes such as copper. Coolant circulates through the tubes to remove heat. The conductive tubes act as electrically conductive lines for connecting various components of the power supply. Where it is desired to make electrical isolation breaks, tubes comprised of insulating material such as nylon are used to provide insulation and continue the fluid circuit.

  14. High voltage power supply with modular series resonant inverters

    DOEpatents

    Dreifuerst, G.R.; Merritt, B.T.

    1995-07-18

    A relatively small and compact high voltage, high current power supply for a laser utilizes a plurality of modules containing series resonant half bridge inverters. A pair of reverse conducting thyristors are incorporated in each series resonant inverter module such that the series resonant inverter modules are sequentially activated in phases 360{degree}/n apart, where n=number of modules for n>2. Selective activation of the modules allows precise output control reducing ripple and improving efficiency. Each series resonant half bridge inverter module includes a transformer which has a cooling manifold for actively circulating a coolant such as water, to cool the transformer core as well as selected circuit elements. Conductors connecting and forming various circuit components comprise hollow, electrically conductive tubes such as copper. Coolant circulates through the tubes to remove heat. The conductive tubes act as electrically conductive lines for connecting various components of the power supply. Where it is desired to make electrical isolation breaks, tubes comprised of insulating material such as nylon are used to provide insulation and continue the fluid circuit. 11 figs.

  15. Invertible apparatus for the reflection of solar radiation

    SciTech Connect

    Urruela, J.R.

    1981-04-28

    Apparatus for reflecting light including a head carrying a reflecting panel and mounted for rotation on a column, said head including a mechanism for rotating said panel about a horizontal axis between a first range of positions for following the sun and an inverted position, said mechanism including an articulated quadrilateral controlled by a linear actuator.

  16. Malicious attacks on media authentication schemes based on invertible watermarks

    NASA Astrophysics Data System (ADS)

    Katzenbeisser, Stefan; Dittmann, Jana

    2004-06-01

    The increasing availability and distribution of multimedia technology has made the manipulation of digital images, videos or audio files easy. While this enables numerous new applications, a certain loss of trust in digital media can be observed. In general, there is no guarantee that a digital image "does not lie", i.e., that the image content was not altered. To counteract this risk, fragile watermarks were proposed to protect the integrity of digital multimedia objects. In high security applications, it is necessary to be able to reconstruct the original object out of the watermarked version. This can be achieved by the use of invertible watermarks. While traditional watermarking schemes introduce some small non-invertible distortion in the digital content, invertible watermarks can be completely removed from a watermarked work. In the past, the security of proposed image authentication schemes based on invertible watermarks was only analyzed using ad-hoc methods and neglected the possibility of malicious attacks, which aim at engineering a fake mark so that the attacked object appears to be genuine. In this paper, we characterize and analyze possible malicious attacks against watermark-based image authentication systems and explore the theoretical limits of previous constructions with respect to their security.

  17. Effects of morphology on the flapping dynamics of inverted flags

    NASA Astrophysics Data System (ADS)

    Fan, Boyu; Cosse, Julia; Sader, John; Gharib, Morteza

    2014-11-01

    The behavior of inverted flags has received recent attention in the study of the interaction of flexible bodies with fluid flows. It has implications in a variety of natural phenomena, such as the fluttering of leaves in the wind. As opposed to a conventional flag, defined by a fixed leading edge and a free trailing edge, an inverted flag has a free leading edge and a fixed trailing edge. The reversed flow orientation of inverted flags has led to a surprising observation. Over a narrow range of wind speeds, they exhibit a large-amplitude flapping motion that is not present in their conventional counterparts. Our study experimentally investigates the effects of flag morphology on the flapping behavior of inverted flags. Different flags ranging from rectangles to triangles are studied in a wind tunnel to assess the underlying parameters that govern their dynamics. We observe a significant shift in the limit-cycle flapping mode that is a function of flag shape parameters. This research is supported by the Lester Lees Aeronautics Summer Undergraduate Research Fellowship and the Gordon and Betty Moore Foundation.

  18. 3. DETAIL OF INVERTED MINE LOCOMOTIVE OR "MOTOR," USED FOR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. DETAIL OF INVERTED MINE LOCOMOTIVE OR "MOTOR," USED FOR SURFACE HAULAGE OF MINE CARS, LOOKING SOUTHWEST; NOTE GEARING - Nuttallburg Mine Complex, Main Mine, North side of New River, 2.7 miles upstream from Fayette Landing, Lookout, Fayette County, WV

  19. A modified split-supply switched-reluctance drive inverter

    SciTech Connect

    Chan, S.; Omar, A.M.

    1995-12-31

    This paper describes the application of a new simple voltage-boosting feature to split-supply SR (switched-reluctance) inverter. As its name implies, the SR motor always operates in switching mode and has distinct motoring and generating rotor angular regions. The effectiveness of the energy conversion process of SR motor depends basically on the ability of its inverter to inject adequate current during the positive-torque angular region and to reduce the current to negligible value during negative-torque angular region. The modified inverter effectively generates boost voltages for accelerating current build-up and decay and hence enhances the performance of SR drives. Benefits of the added boosting include: higher average current, better energy recovery during commutation and a wider feasible speed range. This paper will assess the implications of the boost feature on inverter cost and performance. A time-stepping simulation procedure which includes the modelling of current overlapping between phases will be presented together with simulation results.

  20. Quenching mechanism of exciplex fluorescence by inverted micelles

    SciTech Connect

    Sato, Chika; Kikuchi, Koichi

    1992-06-25

    Using an emission-absorption laser photolysis method, the quenching mechanism of the pyrene-N,N-dimethylaniline exciplex fluorscence by inverted micelles is studied. The rate of enhanced intersystem crossing depends upon water pool size and is reduced by external magnetic fields. 15 refs., 3 figs., 2 tabs.

  1. Repeat-Associated Fission Yeast-Like Regional Centromeres in the Ascomycetous Budding Yeast Candida tropicalis.

    PubMed

    Chatterjee, Gautam; Sankaranarayanan, Sundar Ram; Guin, Krishnendu; Thattikota, Yogitha; Padmanabhan, Sreedevi; Siddharthan, Rahul; Sanyal, Kaustuv

    2016-02-01

    The centromere, on which kinetochore proteins assemble, ensures precise chromosome segregation. Centromeres are largely specified by the histone H3 variant CENP-A (also known as Cse4 in yeasts). Structurally, centromere DNA sequences are highly diverse in nature. However, the evolutionary consequence of these structural diversities on de novo CENP-A chromatin formation remains elusive. Here, we report the identification of centromeres, as the binding sites of four evolutionarily conserved kinetochore proteins, in the human pathogenic budding yeast Candida tropicalis. Each of the seven centromeres comprises a 2 to 5 kb non-repetitive mid core flanked by 2 to 5 kb inverted repeats. The repeat-associated centromeres of C. tropicalis all share a high degree of sequence conservation with each other and are strikingly diverged from the unique and mostly non-repetitive centromeres of related Candida species--Candida albicans, Candida dubliniensis, and Candida lusitaniae. Using a plasmid-based assay, we further demonstrate that pericentric inverted repeats and the underlying DNA sequence provide a structural determinant in CENP-A recruitment in C. tropicalis, as opposed to epigenetically regulated CENP-A loading at centromeres in C. albicans. Thus, the centromere structure and its influence on de novo CENP-A recruitment has been significantly rewired in closely related Candida species. Strikingly, the centromere structural properties along with role of pericentric repeats in de novo CENP-A loading in C. tropicalis are more reminiscent to those of the distantly related fission yeast Schizosaccharomyces pombe. Taken together, we demonstrate, for the first time, fission yeast-like repeat-associated centromeres in an ascomycetous budding yeast. PMID:26845548

  2. Repeat-Associated Fission Yeast-Like Regional Centromeres in the Ascomycetous Budding Yeast Candida tropicalis

    PubMed Central

    Chatterjee, Gautam; Sankaranarayanan, Sundar Ram; Guin, Krishnendu; Thattikota, Yogitha; Padmanabhan, Sreedevi; Siddharthan, Rahul; Sanyal, Kaustuv

    2016-01-01

    The centromere, on which kinetochore proteins assemble, ensures precise chromosome segregation. Centromeres are largely specified by the histone H3 variant CENP-A (also known as Cse4 in yeasts). Structurally, centromere DNA sequences are highly diverse in nature. However, the evolutionary consequence of these structural diversities on de novo CENP-A chromatin formation remains elusive. Here, we report the identification of centromeres, as the binding sites of four evolutionarily conserved kinetochore proteins, in the human pathogenic budding yeast Candida tropicalis. Each of the seven centromeres comprises a 2 to 5 kb non-repetitive mid core flanked by 2 to 5 kb inverted repeats. The repeat-associated centromeres of C. tropicalis all share a high degree of sequence conservation with each other and are strikingly diverged from the unique and mostly non-repetitive centromeres of related Candida species—Candida albicans, Candida dubliniensis, and Candida lusitaniae. Using a plasmid-based assay, we further demonstrate that pericentric inverted repeats and the underlying DNA sequence provide a structural determinant in CENP-A recruitment in C. tropicalis, as opposed to epigenetically regulated CENP-A loading at centromeres in C. albicans. Thus, the centromere structure and its influence on de novo CENP-A recruitment has been significantly rewired in closely related Candida species. Strikingly, the centromere structural properties along with role of pericentric repeats in de novo CENP-A loading in C. tropicalis are more reminiscent to those of the distantly related fission yeast Schizosaccharomyces pombe. Taken together, we demonstrate, for the first time, fission yeast-like repeat-associated centromeres in an ascomycetous budding yeast. PMID:26845548

  3. Efficiency modeling and evaluation of a resonant snubber based soft- switching inverter for motor drive applications

    SciTech Connect

    Lai, J.S.; Young, R.W.; Ott, G.W.

    1995-12-31

    This paper establishes an analytical model for a resonant snubber based soft-switching inverter. The model adopts loss separation method to evaluate losses in individual components. Because of symmetry of the inverter circuit, the developed model is suitable for both single-phase and three-phase inverters. A single-phase inverter was built and tested with a single-phase induction motor driving a fan load to verify the developed model. The equivalent single-phase induction motor model was curve-fitted from experiment. Analytical results showed reasonable agreement with experiment. The same efficiency evaluation method was then applied to the conventional hard-switching inverter, and the results were compared with that of the soft-switching inverter. The resonant snubber base soft-switching inverter shows substantial efficiency improvement over the hard switching PWM (pulse-width-modulation) inverter, especially in low speed operation.

  4. A multilevel voltage-source inverter with separate dc sources for static var generation

    SciTech Connect

    Peng, Fang Zheng |; Lai, Jih-Sheng; McKeever, J.; VanCoevering, J.

    1995-09-01

    A new multilevel voltage-source inverter with a separate dc sources is proposed for high-voltage, high-power applications, such as flexible ac transmission systems (FACTS) including static var generation (SVG), power line conditioning, series compensation, phase shifting, voltage balancing, fuel cell and photovoltaic utility systems interfacing, etc. The new M-level inverter consists of (M-1)/2 single phase full bridges in which each bridge has its own separate dc source. This inverter can generate almost sinusoidal waveform voltage with only one time switching per cycle as the number of levels increases. It can solve the problems of conventional transformer-based multipulse inverters and the problems of the multilevel diode-clamped inverter and the multilevel flying capacitor inverter. To demonstrate the superiority of the new inverter, a SVG system using the new inverter topology is discussed through analysis, simulation and experiment.

  5. Improved current control makes inverters the power sources of choice

    SciTech Connect

    Yamamoto, H.; Harada, S.; Ueyama, T.

    1997-02-01

    It is now generally understood that by increasing the operating or switching frequency of a power source the size of the main transformer and main reactor can be shrunk. Thus, a 300-A DC welding power source weighing well under 100 lb can be produced. This makes the inverter power source an ideal choice for applications requiring equipment maneuverability. It is also generally understood that due to higher switching frequencies, a smoother output is obtained from inverter power sources. In the late 1980s, the company developed a new double-inverter power source by which inverted DC weld output is inverted back to AC weld output. This product was the first of its kind in the world. Again, the small compact size of this product was of great interest. Utilizing current waveform control, it was realized that fast response switching from electrode negative to electrode positive could be accurately controlled, offering benefits such as AC GTA welding with high-frequency start only, even at a low welding current. The primary benefit is the ability to limit the electrode positive half cycle to less than 5%. The electrode positive half cycle is responsible for tungsten erosion, which also creates the balling effect of a tungsten electrode. By limiting the electrode positive portion of the AC cycle to a very low level, a rather sharp point can be maintained on the tungsten, which creates a very concentrated, focused arc column. This ability provides excellent joint penetration in fillet welding of aluminum alloys, especially on thick plate. It also reduces the heat-affected zone in AC GTA welding of aluminum.

  6. Bypass ZVS-PWM High-Frequency Inverter for Induction Heating

    NASA Astrophysics Data System (ADS)

    Shoji, Hiroyuki; Uruno, Junpei; Isogai, Masayuki

    In this paper, we present a novel circuit topology for achieving thezero-voltage switching (ZVS) operation in a high-frequency inverter. The output power of the inverter is regulated over a wide range using a pulse widthmodulation (PWM) technique and by connecting a bypass circuit to a conventional single-ended push-pull (SEPP) high-frequency inverter for induction heating. All the switching devices of the proposed inverter are operated in the ZVS mode.

  7. Electrical power inverter having a phase modulated, twin-inverter, high frequency link and an energy storage module

    DOEpatents

    Pitel, I.J.

    1987-02-03

    The present invention provides an electrical power inverter method and apparatus, which includes a high frequency link, for converting DC power into AC power. Generally stated, the apparatus includes a first high frequency module which produces an AC voltage at a first output frequency, and a second high frequency inverter module which produces an AC voltage at a second output frequency that is substantially the same as the first output frequency. The second AC voltage is out of phase with the first AC voltage by a selected angular phase displacement. A mixer mixes the first and second output voltages to produce a high frequency carrier which has a selected base frequency impressed on the sidebands thereof. A rectifier rectifies the carrier, and a filter filters the rectified carrier. An output inverter inverts the filtered carrier to produce an AC line voltage at the selected base frequency. A phase modulator adjusts the relative angular phase displacement between the outputs of the first and second high frequency modules to control the base frequency and magnitude of the AC line voltage. 19 figs.

  8. Electrical power inverter having a phase modulated, twin-inverter, high frequency link and an energy storage module

    DOEpatents

    Pitel, Ira J.

    1987-02-03

    The present invention provides an electrical power inverter method and apparatus, which includes a high frequency link, for converting DC power into AC power. Generally stated, the apparatus includes a first high frequency module which produces an AC voltage at a first output frequency, and a second high frequency inverter module which produces an AC voltage at a second output frequency that is substantially the same as the first output frequency. The second AC voltage is out of phase with the first AC voltage by a selected angular phase displacement. A mixer mixes the first and second output voltages to produce a high frequency carrier which has a selected base frequency impressed on the sidebands thereof. A rectifier rectifies the carrier, and a filter filters the rectified carrier. An output inverter inverts the filtered carrier to produce an AC line voltage at the selected base frequency. A phase modulator adjusts the relative angular phase displacement between the outputs of the first and second high frequency modules to control the base frequency and magnitude of the AC line voltage.

  9. Analysis and carrier-based modulation of Z-source NPC inverters

    NASA Astrophysics Data System (ADS)

    Dehghan, Seyed Mohammad; Mohamadian, Mustafa; Gharekhani, Reza

    2012-08-01

    Multi-level neutral-point-clamped (NPC) inverters are widely used in high and medium voltage applications. However, these inverters are only buck-type converters. Recently z-source NPC inverters have been proposed as the buck-boost three-level inverter. New inverters use a z-source network as the input stage. This article analyses the features and limitations of two main topologies of z-source NPC inverters (dual z-source network NPC inverter and single z-source network NPC inverter). The low-frequency ripple of the inductor current and the capacitor voltage of the z-source networks in the z-source NPC inverters are surveyed. This article also proposes two novel PWM methods for the z-source NPC inverters, which can be easily implemented experimentally. In the proposed methods, generated switching signals for the conventional NPC inverter are modified for the z-source NPC inverter using a simple logic circuit considering the boost factors and the power sharing ratio. The performance of the proposed simple PWM methods is verified by simulation and experimental results.

  10. Advanced Inverter Functions to Support High Levels of Distributed Solar: Policy and Regulatory Considerations (Brochure)

    SciTech Connect

    Not Available

    2014-11-01

    This paper explains how advanced inverter functions (sometimes called 'smart inverters') contribute to the integration of high levels of solar PV generation onto the electrical grid and covers the contributions of advanced functions to maintaining grid stability. Policy and regulatory considerations associated with the deployment of advanced inverter functions are also introduced.

  11. Variable-frequency inverter controls torque, speed, and braking in ac induction motors

    NASA Technical Reports Server (NTRS)

    Nola, F. J.

    1974-01-01

    Dc to ac inverter provides optimum frequency and voltage to ac induction motor, in response to different motor-load and speed requirements. Inverter varies slip frequency of motor in proportion to required torque. Inverter protects motor from high current surges, controls negative slip to apply braking, and returns energy stored in momentum of load to dc power source.

  12. The research of multilevel transistor inverter for converting energy of solar panels

    NASA Astrophysics Data System (ADS)

    Taissariyeva, K. N.; Issembergenov, N. T.

    2015-09-01

    This article considers multilevel transistor inverter for converting energy of solar panels into electroenergy. The output of multilevel transistor inverter produces the voltage of almost sinusoidal form. The primary objective of this inverter is to transform solar energy into electroenergy of industrial frequency. The analysis of received output curves of voltage for sinusoidality has been conducted.

  13. Telomerase Repeated Amplification Protocol (TRAP)

    PubMed Central

    Mender, Ilgen; Shay, Jerry W.

    2016-01-01

    Telomeres are found at the end of eukaryotic linear chromosomes, and proteins that bind to telomeres protect DNA from being recognized as double-strand breaks thus preventing end-to-end fusions (Griffith et al., 1999). However, due to the end replication problem and other factors such as oxidative damage, the limited life span of cultured cells (Hayflick limit) results in progressive shortening of these protective structures (Hayflick and Moorhead, 1961; Olovnikov, 1973). The ribonucleoprotein enzyme complex telomerase-consisting of a protein catalytic component hTERT and a functional RNA component hTR or hTERC- counteracts telomere shortening by adding telomeric repeats to the end of chromosomes in ~90% of primary human tumors and in some transiently proliferating stem-like cells (Shay and Wright, 1996; Shay and Wright, 2001). This results in continuous proliferation of cells which is a hallmark of cancer. Therefore, telomere biology has a central role in aging, cancer progression/metastasis as well as targeted cancer therapies. There are commonly used methods in telomere biology such as Telomere Restriction Fragment (TRF) (Mender and Shay, 2015b), Telomere Repeat Amplification Protocol (TRAP) and Telomere dysfunction Induced Foci (TIF) analysis (Mender and Shay, 2015a). In this detailed protocol we describe Telomere Repeat Amplification Protocol (TRAP). The TRAP assay is a popular method to determine telomerase activity in mammalian cells and tissue samples (Kim et al., 1994). The TRAP assay includes three steps: extension, amplification, and detection of telomerase products. In the extension step, telomeric repeats are added to the telomerase substrate (which is actually a non telomeric oligonucleotide, TS) by telomerase. In the amplification step, the extension products are amplified by the polymerase chain reaction (PCR) using specific primers (TS upstream primer and ACX downstream primer) and in the detection step, the presence or absence of telomerase is

  14. Accumulate Repeat Accumulate Coded Modulation

    NASA Technical Reports Server (NTRS)

    Abbasfar, Aliazam; Divsalar, Dariush; Yao, Kung

    2004-01-01

    In this paper we propose an innovative coded modulation scheme called 'Accumulate Repeat Accumulate Coded Modulation' (ARA coded modulation). This class of codes can be viewed as serial turbo-like codes, or as a subclass of Low Density Parity Check (LDPC) codes that are combined with high level modulation. Thus at the decoder belief propagation can be used for iterative decoding of ARA coded modulation on a graph, provided a demapper transforms the received in-phase and quadrature samples to reliability of the bits.

  15. Cloning and Characterization of a Human Genomic Sequence that Alleviates Repeat-Induced Gene Silencing.

    PubMed

    Fukuma, Miki; Ganmyo, Yuto; Miura, Osamu; Ohyama, Takashi; Shimizu, Noriaki

    2016-01-01

    Plasmids bearing a mammalian replication initiation region (IR) and a nuclear matrix attachment region (MAR) are spontaneously amplified in transfected mammalian cells, and such amplification generates chromosomal homogeneously staining regions (HSRs) or extrachromosomal double minutes (DMs). This method provides a novel, efficient, and rapid way to establish cells that stably produce high levels of recombinant proteins. However, because IR/MAR plasmids are amplified as repeats, they are frequently targeted by repeat-induced gene silencing (RIGS), which silences a variety of repeated sequences in transgenes and the genome. To address this problem, we developed a novel screening system using the IR/MAR plasmid to isolate human genome sequences that alleviate RIGS. The screen identified a 3,271 bp sequence (B-3-31) that elevated transgene expression without affecting the amplification process. Neither non-B structure (i.e., the inverted repeats or bending) nor known epigenetic modifier elements such as MARs, insulators, UCOEs, or STARs could explain the anti-silencing activity of B-3-31. Instead, the activity was distributed throughout the entire B-3-31 sequence, which was extremely A/T-rich and CpG-poor. Because B-3-31 effectively and reproducibly alleviated RIGS of repeated genes, it could be used to increase recombinant protein production. PMID:27078685

  16. Gene Conversion Violates the Stepwise Mutation Model for Microsatellites in Y-Chromosomal Palindromic Repeats

    PubMed Central

    Balaresque, Patricia; King, Turi E; Parkin, Emma J; Heyer, Evelyne; Carvalho-Silva, Denise; Kraaijenbrink, Thirsa; de Knijff, Peter; Tyler-Smith, Chris; Jobling, Mark A

    2014-01-01

    The male-specific region of the human Y chromosome (MSY) contains eight large inverted repeats (palindromes), in which high-sequence similarity between repeat arms is maintained by gene conversion. These palindromes also harbor microsatellites, considered to evolve via a stepwise mutation model (SMM). Here, we ask whether gene conversion between palindrome microsatellites contributes to their mutational dynamics. First, we study the duplicated tetranucleotide microsatellite DYS385a,b lying in palindrome P4. We show, by comparing observed data with simulated data under a SMM within haplogroups, that observed heteroallelic combinations in which the modal repeat number difference between copies was large, can give rise to homoallelic combinations with zero-repeats difference, equivalent to many single-step mutations. These are unlikely to be generated under a strict SMM, suggesting the action of gene conversion. Second, we show that the intercopy repeat number difference for a large set of duplicated microsatellites in all palindromes in the MSY reference sequence is significantly reduced compared with that for nonpalindrome-duplicated microsatellites, suggesting that the former are characterized by unusual evolutionary dynamics. These observations indicate that gene conversion violates the SMM for microsatellites in palindromes, homogenizing copies within individual Y chromosomes, but increasing overall haplotype diversity among chromosomes within related groups. PMID:24610746

  17. Gene conversion violates the stepwise mutation model for microsatellites in y-chromosomal palindromic repeats.

    PubMed

    Balaresque, Patricia; King, Turi E; Parkin, Emma J; Heyer, Evelyne; Carvalho-Silva, Denise; Kraaijenbrink, Thirsa; de Knijff, Peter; Tyler-Smith, Chris; Jobling, Mark A

    2014-05-01

    The male-specific region of the human Y chromosome (MSY) contains eight large inverted repeats (palindromes), in which high-sequence similarity between repeat arms is maintained by gene conversion. These palindromes also harbor microsatellites, considered to evolve via a stepwise mutation model (SMM). Here, we ask whether gene conversion between palindrome microsatellites contributes to their mutational dynamics. First, we study the duplicated tetranucleotide microsatellite DYS385a,b lying in palindrome P4. We show, by comparing observed data with simulated data under a SMM within haplogroups, that observed heteroallelic combinations in which the modal repeat number difference between copies was large, can give rise to homoallelic combinations with zero-repeats difference, equivalent to many single-step mutations. These are unlikely to be generated under a strict SMM, suggesting the action of gene conversion. Second, we show that the intercopy repeat number difference for a large set of duplicated microsatellites in all palindromes in the MSY reference sequence is significantly reduced compared with that for nonpalindrome-duplicated microsatellites, suggesting that the former are characterized by unusual evolutionary dynamics. These observations indicate that gene conversion violates the SMM for microsatellites in palindromes, homogenizing copies within individual Y chromosomes, but increasing overall haplotype diversity among chromosomes within related groups. PMID:24610746

  18. Cloning and Characterization of a Human Genomic Sequence that Alleviates Repeat-Induced Gene Silencing

    PubMed Central

    Miura, Osamu; Ohyama, Takashi; Shimizu, Noriaki

    2016-01-01

    Plasmids bearing a mammalian replication initiation region (IR) and a nuclear matrix attachment region (MAR) are spontaneously amplified in transfected mammalian cells, and such amplification generates chromosomal homogeneously staining regions (HSRs) or extrachromosomal double minutes (DMs). This method provides a novel, efficient, and rapid way to establish cells that stably produce high levels of recombinant proteins. However, because IR/MAR plasmids are amplified as repeats, they are frequently targeted by repeat-induced gene silencing (RIGS), which silences a variety of repeated sequences in transgenes and the genome. To address this problem, we developed a novel screening system using the IR/MAR plasmid to isolate human genome sequences that alleviate RIGS. The screen identified a 3,271 bp sequence (B-3-31) that elevated transgene expression without affecting the amplification process. Neither non-B structure (i.e., the inverted repeats or bending) nor known epigenetic modifier elements such as MARs, insulators, UCOEs, or STARs could explain the anti-silencing activity of B-3-31. Instead, the activity was distributed throughout the entire B-3-31 sequence, which was extremely A/T-rich and CpG-poor. Because B-3-31 effectively and reproducibly alleviated RIGS of repeated genes, it could be used to increase recombinant protein production. PMID:27078685

  19. Low-copy repeats at the human VIPR2 gene predispose to recurrent and nonrecurrent rearrangements

    PubMed Central

    Beri, Silvana; Bonaglia, Maria Clara; Giorda, Roberto

    2013-01-01

    Submicroscopic structural variations, including deletions, duplications, inversions and more complex rearrangements, are widespread in normal human genomes. Inverted segmental duplications or highly identical low-copy repeat (LCR) sequences can mediate the formation of inversions and more complex structural rearrangements through non-allelic homologous recombination. In a patient with 7q36 inverted duplication/terminal deletion, we demonstrated the central role of a pair of short inverted LCRs in the vasoactive intestinal peptide receptor gene (VIPR2)-LCRs in generating the rearrangement. We also revealed a relatively common VIPR2-LCR-associated inversion polymorphism disrupting the gene in almost 1% of healthy subjects, and a small number of complex duplications/triplications. In genome-wide studies of several thousand patients, a significant association of rare microduplications with variable size, all involving VIPR2, with schizophrenia was recently described, suggesting that altered vasoactive intestinal peptide signaling is likely implicated in the pathogenesis of schizophrenia. Genetic testing for VIPR2-LCR-associated inversions should be performed on available cohorts of psychiatric patients to evaluate their potential pathogenic role. PMID:23073313

  20. Crowding by a repeating pattern

    PubMed Central

    Rosen, Sarah; Pelli, Denis G.

    2015-01-01

    Theinability to recognize a peripheral target among flankers is called crowding. For a foveal target, crowding can be distinguished from overlap masking by its sparing of detection, linear scaling with eccentricity, and invariance with target size.Crowding depends on the proximity and similarity of the flankers to the target. Flankers that are far from or dissimilar to the target do not crowd it. On a gray page, text whose neighboring letters have different colors, alternately black and white, has enough dissimilarity that it might escape crowding. Since reading speed is normally limited by crowding, escape from crowding should allow faster reading. Yet reading speed is unchanged (Chung & Mansfield, 2009). Why? A recent vernier study found that using alternating-color flankers produces strong crowding (Manassi, Sayim, & Herzog, 2012). Might that effect occur with letters and reading? Critical spacing is the minimum center-to-center target–flanker spacing needed to correctly identify the target. We measure it for a target letter surrounded by several equidistant flanker letters of the same polarity, opposite polarity, or mixed polarity: alternately white and black. We find strong crowding in the alternating condition, even though each flanker letter is beyond its own critical spacing (as measured in a separate condition). Thus a periodic repeating pattern can produce crowding even when the individual elements do not. Further, in all conditions we find that, once a periodic pattern repeats (two cycles), further repetition does not affect critical spacing of the innermost flanker. PMID:26024457

  1. A study on the impact of high penetration distributed generation inverters on grid operation and stability

    NASA Astrophysics Data System (ADS)

    Gu, Fei; Brouwer, Jack; Samuelsen, Scott

    2013-09-01

    Recent advances in inverter technology have enabled ancillary services such as volt/VAR regulation, SCADA communications, and active power filtering. Smart inverters can not only provide real power, but can be controlled to use excess capacity to provide reactive power compensation, power flow control, and active power filtering without supplementary inverter hardware. A transient level inverter model based on the Solectria 7700 inverter is developed and used to assess these control strategies using field data from an existing branch circuit containing two Amonix 68kW CPV-7700 systems installed at the University of California, Irvine.

  2. Repeat-swap homology modeling of secondary active transporters: updated protocol and prediction of elevator-type mechanisms.

    PubMed

    Vergara-Jaque, Ariela; Fenollar-Ferrer, Cristina; Kaufmann, Desirée; Forrest, Lucy R

    2015-01-01

    Secondary active transporters are critical for neurotransmitter clearance and recycling during synaptic transmission and uptake of nutrients. These proteins mediate the movement of solutes against their concentration gradients, by using the energy released in the movement of ions down pre-existing concentration gradients. To achieve this, transporters conform to the so-called alternating-access hypothesis, whereby the protein adopts at least two conformations in which the substrate binding sites are exposed to one or other side of the membrane, but not both simultaneously. Structures of a bacterial homolog of neuronal glutamate transporters, GltPh, in several different conformational states have revealed that the protein structure is asymmetric in the outward- and inward-open states, and that the conformational change connecting them involves a elevator-like movement of a substrate binding domain across the membrane. The structural asymmetry is created by inverted-topology repeats, i.e., structural repeats with similar overall folds whose transmembrane topologies are related to each other by two-fold pseudo-symmetry around an axis parallel to the membrane plane. Inverted repeats have been found in around three-quarters of secondary transporter folds. Moreover, the (a)symmetry of these systems has been successfully used as a bioinformatic tool, called "repeat-swap modeling" to predict structural models of a transporter in one conformation using the known structure of the transporter in the complementary conformation as a template. Here, we describe an updated repeat-swap homology modeling protocol, and calibrate the accuracy of the method using GltPh, for which both inward- and outward-facing conformations are known. We then apply this repeat-swap homology modeling procedure to a concentrative nucleoside transporter, VcCNT, which has a three-dimensional arrangement related to that of GltPh. The repeat-swapped model of VcCNT predicts that nucleoside transport also

  3. Repeat-swap homology modeling of secondary active transporters: updated protocol and prediction of elevator-type mechanisms

    PubMed Central

    Vergara-Jaque, Ariela; Fenollar-Ferrer, Cristina; Kaufmann, Desirée; Forrest, Lucy R.

    2015-01-01

    Secondary active transporters are critical for neurotransmitter clearance and recycling during synaptic transmission and uptake of nutrients. These proteins mediate the movement of solutes against their concentration gradients, by using the energy released in the movement of ions down pre-existing concentration gradients. To achieve this, transporters conform to the so-called alternating-access hypothesis, whereby the protein adopts at least two conformations in which the substrate binding sites are exposed to one or other side of the membrane, but not both simultaneously. Structures of a bacterial homolog of neuronal glutamate transporters, GltPh, in several different conformational states have revealed that the protein structure is asymmetric in the outward- and inward-open states, and that the conformational change connecting them involves a elevator-like movement of a substrate binding domain across the membrane. The structural asymmetry is created by inverted-topology repeats, i.e., structural repeats with similar overall folds whose transmembrane topologies are related to each other by two-fold pseudo-symmetry around an axis parallel to the membrane plane. Inverted repeats have been found in around three-quarters of secondary transporter folds. Moreover, the (a)symmetry of these systems has been successfully used as a bioinformatic tool, called “repeat-swap modeling” to predict structural models of a transporter in one conformation using the known structure of the transporter in the complementary conformation as a template. Here, we describe an updated repeat-swap homology modeling protocol, and calibrate the accuracy of the method using GltPh, for which both inward- and outward-facing conformations are known. We then apply this repeat-swap homology modeling procedure to a concentrative nucleoside transporter, VcCNT, which has a three-dimensional arrangement related to that of GltPh. The repeat-swapped model of VcCNT predicts that nucleoside transport

  4. 47 CFR 22.1015 - Repeater operation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Repeater operation. 22.1015 Section 22.1015 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES PUBLIC MOBILE SERVICES Offshore Radiotelephone Service § 22.1015 Repeater operation. Offshore central stations may be used as repeater stations provided that...

  5. Repeated Reading. What Works Clearinghouse Intervention Report

    ERIC Educational Resources Information Center

    What Works Clearinghouse, 2014

    2014-01-01

    "Repeated reading" is an academic practice that aims to increase oral reading fluency. "Repeated reading" can be used with students who have developed initial word reading skills but demonstrate inadequate reading fluency for their grade level. During "repeated reading," a student sits in a quiet location with a…

  6. Statistics of a noise-driven elastic inverted pendulum

    NASA Astrophysics Data System (ADS)

    Halvorsen, Einar; Litak, Grzegorz

    2015-04-01

    Recently an elastic inverted pendulum structure was proposed as a means to make nonlinear energy harvesters. An effective dynamical model of this bi-stable system has an effective lumped mass that is dependent on the displacement, hence preventing direct application of previous analyses for nonlinear harvesters driven by random vibrations. We have set up a stationary Fokker-Planck equation for the inverted pendulum and solved it to obtain explicit expressions for the stationary probability densities of the system. We found that the marginal distribution of velocity is non-Gaussian, but numerically it differs little from a Gaussian when parameters for a recently published device are used. The conditional probability of position given velocity, has two peaks for low velocities. These merge into one upon increase of velocity.

  7. Adaptive control system for line-commutated inverters

    NASA Technical Reports Server (NTRS)

    Dolland, C. R.; Bailey, D. A. (Inventor)

    1983-01-01

    A control system for a permanent magnet motor driven by a multiphase line commutated inverter is provided with integration for integrating the back EMF of each phase of the motor. This is used in generating system control signals for an inverter gate logic using a sync and firing angle (alpha) control generator connected to the outputs of the integrators. A precision full wave rectifier provides a speed control feedback signal to a phase delay rectifier via a gain and loop compensation circuit and to the integrators for adaptive control of the attenuation of low frequencies by the integrators as a function of motor speed. As the motor speed increases, the attenuation of low frequency components by the integrators is increased to offset the gain of the integrators to spurious low frequencies.

  8. Amphoteric water-in-oil self-inverting polymer emulsion

    SciTech Connect

    Lipowski, S. A.

    1985-11-12

    An amphoteric water-in-oil self-inverting polymer emulsion is prepared which contains a copolymer of a nonionic vinyl monomer and an amphoteric vinyl monomer or a terpolymer of a nonionic vinyl monomer, an anionic vinyl monomer and a cationic vinyl monomer in the aqueous phase, a hydrocarbon oil for the oil phase, a water-in-oil emulsifying agent and an inverting surfactant. An example of a copolymer is a copolymer of a nonionic vinyl monomer such as acrylamide or methacrylamide and an amphoteric vinyl monomer such as a reaction product of dimethylaminoethyl methacrylate and monochloracetic acid. An example of a terpolymer is a terpolymer of a nonionic vinyl monomer such as acrylamide or methacrylamide, an anionic vinyl monomer such as sodium acrylate and a cationic vinyl monomer such as triethyl ammonium ethyl methacrylate methosulfate salt. The emulsion is useful in papermaking, treatment of sewage and industrial wastes, drilling muds and secondary and tertiary recovery of petroleum by water flooding.

  9. Theoretical investigation of the oceanic inverted barometer response

    NASA Technical Reports Server (NTRS)

    Dickman, S. R.

    1988-01-01

    Dynamic tidal theory is generalized in order to predict the oceanic response to atmospheric pressure variations. The oceans are found to exhibit distinct dynamic behavior when forced at periods less than one week; depending on the harmonic type of forcing, the amplitude of the response can differ by about 20 percent or more from the static response. Even at roughly two months the traditional 'inverted barometer' may not be sufficiently accurate for applications in which detection of long-term sea level trends or vertical crustal motion is the goal. For forcing at periods of order one year the oceanic response differs by at most a few percent from the static (not the inverted barometer) response; thus calculations of meteorological excitation of the annual and Chandler wobbles can employ the static approximation without reservation.

  10. Tripless control method for general-purpose inverters

    SciTech Connect

    Mutoh, N.; Ueda, A. . Hitachi Research Lab.); Nandoh, K.; Ibori, S. )

    1992-09-01

    In this paper a new control method is described. This method prevents general-purpose inverters without current regulators from tripping easily, i.e., to be tripless no matter how their load is varied, and enables motors to rotate stably at high frequencies. This control is performed using only current sensors and is a combination of PWM control and torque control. This approach for PWM control changes an asynchronized mode to a synchronized mode when the modulation ratio becomes more than one. This enables the carrier wave frequency to be continuously varied with the inverter frequency. As a result, motors can rotate stably over a wide frequency range. The torque control uses a real and reactive component detector, magnetic flux compensator, slip compensator, and current limit controller.

  11. PWM Inverter control and the application thereof within electric vehicles

    DOEpatents

    Geppert, Steven

    1982-01-01

    An inverter (34) which provides power to an A.C. machine (28) is controlled by a circuit (36) employing PWM control strategy whereby A.C. power is supplied to the machine at a preselectable frequency and preselectable voltage. This is accomplished by the technique of waveform notching in which the shapes of the notches are varied to determine the average energy content of the overall waveform. Through this arrangement, the operational efficiency of the A.C. machine is optimized. The control circuit includes a micro-computer and memory element which receive various parametric inputs and calculate optimized machine control data signals therefrom. The control data is asynchronously loaded into the inverter through an intermediate buffer (38). In its preferred embodiment, the present invention is incorporated within an electric vehicle (10) employing a 144 VDC battery pack (32) and a three-phase induction motor (18).

  12. Inverter-based GTA welding machines improve fabrication

    SciTech Connect

    Sammons, M.

    2000-05-01

    While known as precision process, many fabricators using the gas tungsten arc welding (GTAW) process fight several common problems that hinder quality, slow production, frustrate the operator and otherwise prevent the process from achieving its full potential. These include a limited ability to tailor the weld bead profile, poor control of the arc direction and arc wandering, poor arc starting, unstable or inconsistent arcs in the AC mode, high-frequency interference with electronics and tungsten contamination. Fortunately, new GTA welding technology--made possible by advances with inverter-based power sources and micro-processor controls--can eliminate common productivity gremlins. Further, new AC/DC inverter-based GTA power sources provide advanced arc shaping capabilities. As a result, many fabricators adopting this new technology have experienced phenomenal production increases, taken on new types of projects and reduced costs. Most importantly, the operators enjoy welding more.

  13. Modular synthetic inverters from zinc finger proteins and small RNAs

    DOE PAGESBeta

    Hsia, Justin; Holtz, William J.; Maharbiz, Michel M.; Arcak, Murat; Keasling, Jay D.; Rao, Christopher V.

    2016-02-17

    Synthetic zinc finger proteins (ZFPs) can be created to target promoter DNA sequences, repressing transcription. The binding of small RNA (sRNA) to ZFP mRNA creates an ultrasensitive response to generate higher effective Hill coefficients. Here we combined three “off the shelf” ZFPs and three sRNAs to create new modular inverters in E. coli and quantify their behavior using induction fold. We found a general ordering of the effects of the ZFPs and sRNAs on induction fold that mostly held true when combining these parts. We then attempted to construct a ring oscillator using our new inverters. In conclusion, our chosenmore » parts performed insufficiently to create oscillations, but we include future directions for improvement upon our work presented here.« less

  14. Nonlinear analysis of a family of LC tuned inverters

    NASA Technical Reports Server (NTRS)

    Lee, F. C. Y.; Wilson, T. G.

    1975-01-01

    Four widely used self-oscillating dc-to-square-wave parallel inverters which employ an inductor-capacitor tuned network to determine the oscillation frequency are reduced to a common equivalent RLC network, The techniques of singular-point analysis and state-plane interpretations are employed to describe the steady-state and transient behavior of these circuits and to elucidate the three possible modes of operation: quasi-harmonic, relaxation, and discontinuous. Design guidelines are provided through a study of the influence of circuit parameter variations on the characteristics of oscillation and on frequency stability. Several examples are provided to illustrate the usefulness of this analysis when studying such problems as transistor emitter-to-base junction breakdown during oscillations and the design of starting circuits to insure self-excited oscillations in these inverters.

  15. Completely inverted hysteresis loops: Inhomogeneity effects or experimental artifacts

    SciTech Connect

    Song, C. Cui, B.; Pan, F.; Yu, H. Y.

    2013-11-14

    Completely inverted hysteresis loops (IHL) are obtained by the superconducting quantum interference device with large cooling fields (>10 kOe) in (La,Sr)MnO{sub 3} films with self-assembled LaSrMnO{sub 4}, an antiferromagnetic interface. Although the behaviours of measured loops show many features characteristic to the IHL, its origin, however, is not due to the exchange coupling between (La,Sr)MnO{sub 3}/LaSrMnO{sub 4}, an often accepted view on IHL. Instead, we demonstrate that the negative remanence arises from the hysteresis of superconducting coils, which drops abruptly when lower cooling fields are utilized. Hence the completely inverted hysteresis loops are experimental artifacts rather than previously proposed inhomogeneity effects in complicated materials.

  16. Modular Synthetic Inverters from Zinc Finger Proteins and Small RNAs

    PubMed Central

    Hsia, Justin; Holtz, William J.; Maharbiz, Michel M.; Arcak, Murat; Keasling, Jay D.

    2016-01-01

    Synthetic zinc finger proteins (ZFPs) can be created to target promoter DNA sequences, repressing transcription. The binding of small RNA (sRNA) to ZFP mRNA creates an ultrasensitive response to generate higher effective Hill coefficients. Here we combined three “off the shelf” ZFPs and three sRNAs to create new modular inverters in E. coli and quantify their behavior using induction fold. We found a general ordering of the effects of the ZFPs and sRNAs on induction fold that mostly held true when combining these parts. We then attempted to construct a ring oscillator using our new inverters. Our chosen parts performed insufficiently to create oscillations, but we include future directions for improvement upon our work presented here. PMID:26886888

  17. Current control loop of 3-phase grid-connected inverter

    NASA Astrophysics Data System (ADS)

    Jabbar, A. F.; Mansor, M.

    2013-06-01

    This paper presents a comparative study of current control loop in 3-phase inverter which is used to control the active and reactive output power. Generally, current control loop, power control loop and phase lock-loop are the conventional parameters that can be found in an inverter system controlled by the conventional linear control type, for instance proportional (P), integral (I) and derivative (D). If the grid remains stable throughout the day, PID control can be use. However variation of magnitude, frequency, voltage dips, transient, and other related power quality issues occur in a 3-phase grid often affects the control loop. This paper aims to provide an overall review on the available current control techniques used in grid connected system.

  18. Equilibrium and Stability of the Brillouin Flow in Inverted Magnetron

    NASA Astrophysics Data System (ADS)

    Simon, David; Lau, Yue Ying; Franzi, Matt; Greening, Geoff; Gilgenbach, Ronald; Marhdahl, Peter; Hoff, Brad; Luginsland, John

    2012-10-01

    One embodiment of the novel recirculating planar magnetron, RPM [1] utilizes an inverted configuration for fast startup. While the negative mass behavior on the thin electron layer model [2] is well-known for the inverted magnetron, the corresponding behavior for the equilibrium Brillouin flow [3] is an open question. Simulations using the particle-in-cell codes ICEPIC and/or MAGIC will be performed and compared to the solution to the eigenvalue problem that governs the stability of Brillouin flow, leading to a fundamental study of the flow's negative, positive, and infinite mass properties. Research supported by AFOSR (grant#: FA9550-10-1-0104), AFRL, and L-3 Communications Electron Devices. [4pt] [1] R. M. Gilgenbach, et.al., IEEE Trans. Plasma Sci. 39, 980 (2011); Also patent pending.[0pt] [2] D. M. French, et al., Appl. Phys. Lett. 97, 111501 (2010).[0pt] [3] D. Simon, et al., Phys. Plasmas 19, 043103 (2012).

  19. A state observer for the Virgo inverted pendulum

    NASA Astrophysics Data System (ADS)

    Accadia, T.; Acernese, F.; Astone, P.; Ballardin, G.; Barone, F.; Barsuglia, M.; Basti, A.; Bauer, Th. S.; Bebronne, M.; Beker, M. G.; Belletoile, A.; Bitossi, M.; Bizouard, M. A.; Blom, M.; Bondu, F.; Bonelli, L.; Bonnand, R.; Boschi, V.; Bosi, L.; Bouhou, B.; Braccini, S.; Bradaschia, C.; Branchesi, M.; Briant, T.; Brillet, A.; Brisson, V.; Bulik, T.; Bulten, H. J.; Buskulic, D.; Buy, C.; Cagnoli, G.; Calloni, E.; Canuel, B.; Carbognani, F.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cesarini, E.; Chaibi, O.; Chassande-Mottin, E.; Chincarini, A.; Chiummo, A.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colacino, C. N.; Colas, J.; Colla, A.; Colombini, M.; Conte, A.; Corsi, A.; Coulon, J.-P.; Cuoco, E.; D'Antonio, S.; Dattilo, V.; Davier, M.; Day, R.; De Rosa, R.; Debreczeni, G.; Del Pozzo, W.; del Prete, M.; Di Fiore, L.; Di Lieto, A.; Emilio, M. Di Paolo; Virgilio, A. Di; Dietz, A.; Drago, M.; Endrőczi, G.; Fafone, V.; Ferrante, I.; Fidecaro, F.; Fiori, I.; Flaminio, R.; Forte, L. A.; Fournier, J.-D.; Franc, J.; Frasca, S.; Frasconi, F.; Galimberti, M.; Gammaitoni, L.; Garufi, F.; Gáspár, M. E.; Gemme, G.; Genin, E.; Gennai, A.; Giazotto, A.; Gouaty, R.; Granata, M.; Greverie, C.; Guidi, G. M.; Hayau, J.-F.; Heidmann, A.; Heitmann, H.; Hello, P.; Jaranowski, P.; Kowalska, I.; Królak, A.; Leroy, N.; Letendre, N.; Li, T. G. F.; Liguori, N.; Lorenzini, M.; Loriette, V.; Losurdo, G.; Majorana, E.; Maksimovic, I.; Man, N.; Mantovani, M.; Marchesoni, F.; Marion, F.; Marque, J.; Martelli, F.; Masserot, A.; Michel, C.; Milano, L.; Minenkov, Y.; Mohan, M.; Morgado, N.; Morgia, A.; Mours, B.; Naticchioni, L.; Nocera, F.; Pagliaroli, G.; Palladino, L.; Palomba, C.; Paoletti, F.; Parisi, M.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Persichetti, G.; Piergiovanni, F.; Pietka, M.; Pinard, L.; Poggiani, R.; Prato, M.; Prodi, G. A.; Punturo, M.; Puppo, P.; Rabeling, D. S.; Rácz, I.; Rapagnani, P.; Re, V.; Regimbau, T.; Ricci, F.; Robinet, F.; Rocchi, A.; Rolland, L.; Romano, R.; Rosińska, D.; Ruggi, P.; Sassolas, B.; Sentenac, D.; Sperandio, L.; Sturani, R.; Swinkels, B.; Tacca, M.; Taffarello, L.; Toncelli, A.; Tonelli, M.; Torre, O.; Tournefier, E.; Travasso, F.; Vajente, G.; van den Brand, J. F. J.; Van Den Broeck, C.; van der Putten, S.; Vasuth, M.; Vavoulidis, M.; Vedovato, G.; Verkindt, D.; Vetrano, F.; Viceré, A.; Vinet, J.-Y.; Vitale, S.; Vocca, H.; Ward, R. L.; Was, M.; Yvert, M.; Zadroźny, A.; Zendri, J.-P.

    2011-09-01

    We report an application of Kalman filtering to the inverted pendulum (IP) of the Virgo gravitational wave interferometer. Using subspace method system identification techniques, we calculated a linear mechanical model of Virgo IP from experimental transfer functions. We then developed a Kalman filter, based on the obtained state space representation, that estimates from open loop time domain data, the state variables of the system. This allows the observation (and eventually control) of every resonance mode of the IP mechanical structure independently.

  20. Optimization of Nanowire-Resistance Load Logic Inverter.

    PubMed

    Hashim, Yasir; Sidek, Othman

    2015-09-01

    This study is the first to demonstrate characteristics optimization of nanowire resistance load inverter. Noise margins and inflection voltage of transfer characteristics are used as limiting factors in this optimization. Results indicate that optimization depends on resistance value. Increasing of load resistor tends to increasing in noise margins until saturation point, increasing load resistor after this point will not improve noise margins significantly. PMID:26716253

  1. Turning water into rock: The inverted waves effect.

    PubMed

    Häkkinen, Jukka; Gröhn, Lauri

    2016-01-01

    Humans perceive shape in two-dimensional shaded images, and turning such an image upside down can result in inversion of the relief of this image. Previous research indicates that this inversion is caused by assumptions related to overhead illumination, global convexity and viewpoint above the surface. In our article, we describe the inverted waves effect, in which turning an image of waves upside down changes its relief and also its perceived material properties. PMID:27482371

  2. Lyapunov optimal feedback control of a nonlinear inverted pendulum

    NASA Technical Reports Server (NTRS)

    Grantham, W. J.; Anderson, M. J.

    1989-01-01

    Liapunov optimal feedback control is applied to a nonlinear inverted pendulum in which the control torque was constrained to be less than the nonlinear gravity torque in the model. This necessitates a control algorithm which 'rocks' the pendulum out of its potential wells, in order to stabilize it at a unique vertical position. Simulation results indicate that a preliminary Liapunov feedback controller can successfully overcome the nonlinearity and bring almost all trajectories to the target.

  3. Control of the constrained planar simple inverted pendulum

    NASA Technical Reports Server (NTRS)

    Bavarian, B.; Wyman, B. F.; Hemami, H.

    1983-01-01

    Control of a constrained planar inverted pendulum by eigenstructure assignment is considered. Linear feedback is used to stabilize and decouple the system in such a way that specified subspaces of the state space are invariant for the closed-loop system. The effectiveness of the feedback law is tested by digital computer simulation. Pre-compensation by an inverse plant is used to improve performance.

  4. Turning water into rock: The inverted waves effect

    PubMed Central

    Gröhn, Lauri

    2016-01-01

    Humans perceive shape in two-dimensional shaded images, and turning such an image upside down can result in inversion of the relief of this image. Previous research indicates that this inversion is caused by assumptions related to overhead illumination, global convexity and viewpoint above the surface. In our article, we describe the inverted waves effect, in which turning an image of waves upside down changes its relief and also its perceived material properties. PMID:27482371

  5. High Peak Power Gyroklystron with an Inverted Magnetron Injection Gun

    NASA Astrophysics Data System (ADS)

    Read, Michael; Neilson, Jeff; Borchard, Philipp; Ives, Lawrence; Lawson, Wes

    2006-01-01

    This paper describes the design of a 25 MW, 30 GHz gyroklystron amplifier based on a coaxial RF structure. The design includes an inverted magnetron injection gun (MIG) for positioning and cooling the inner conductor. The gun produces a very low spread beam that contributes to a device efficiency of 54%. Details are given of the gun, RF structure, input and output couplers and collector.

  6. GAP analysis towards a design qualification standard development for grid-connected photovoltaic inverters.

    SciTech Connect

    Tamizhmani, Govindasamy; Granata, Jennifer E.; Maracas, George; Ayyanar, Raja; Marinella, Matthew; Venkataramanan, Sai Balasubramanian Alampoondi

    2011-06-01

    A dedicated design qualification standard for PV inverters does not exist. Development of a well-accepted design qualification standard, specifically for PV inverters will significantly improve the reliability and performance of inverters. The existing standards for PV inverters such as ANSI/UL 1741 and IEC 62109-1 primarily focus on safety of PV inverters. The IEC 62093 discusses inverter qualification but it includes all the BOS components. There are other general standards for distributed generators including the IEEE 1547 series of standards which cover major concerns like utility integration but they are not dedicated to PV inverters and are not written from a design qualification point of view. In this paper some of the potential requirements for a design qualification standard for PV inverters are addressed. The missing links in existing PV inverter related standards are identified and with the IEC 62093 as a guideline, the possible inclusions in the framework for a dedicated design qualification standard of PV inverter are discussed. Some of the key missing links are related to electric stress tests. Hence, a method to adapt the existing surge withstand test standards for use in design qualification standard of PV inverter is presented.

  7. Dynamic performance and control of a static var generator using cascade multilevel inverters

    SciTech Connect

    Peng, Fang Zheng; Lai, Jih-Sheng

    1996-10-01

    A cascade multilevel inverter is proposed for static VAR shifting, compensation/generation applications. The new cascade M-level inverter consists of (M-1)/2 single-phase full bridges in which each bridge has its own separate dc source. This inverter can generate almost sinusoidal waveform voltage with only one time switching per cycle. It can eliminate the need for transformers in multipulse inverters. A prototype static VAR generator (SVG) system using 11- level cascade inverter (21-level line-to-line voltage waveform) has been built. The output voltage waveform is equivalent to that of a 60- pulse inverter. This paper focuses on dynamic performance of the cascade inverter based SVG system. Control schemes are proposed to achieve a fast response which is impossible for a conventional static VAR compensator (SVC). Analytical, simulated and experimental results show the superiority of the proposed SVG system.

  8. An SCR inverter with an integral battery charger for electric vehicles

    NASA Technical Reports Server (NTRS)

    Thimmeach, D.

    1983-01-01

    The feasibility of incorporating an onboard battery charger into the inverter previously developed under a NASA contract is successfully demonstrated. The rated output power of the resulting isolated battery charger is 3.6 kW at 220 Vac with an 86 percent efficiency and a 95 percent power factor. Also achieved are improved inverter efficiency (from 90 to 93 percent at 15 kW motor shaft power), inverter peak power capability (from 26 to 34 kW), and reduced weight and volume of the combined inverter/charger package (47 kg, 49 x 44 x 24 cm). Some major conclusions are that using the inverter commutation circuitry to perform the battery charging function is advantageous, and that the input-commutated thyristor inverter has the potential to be an excellent inverter and battery charger for use in electric vehicle applications.

  9. Inverted channel deposits on the floor of Miyamoto crater, Mars

    USGS Publications Warehouse

    Newsom, Horton E.; Lanza, N.L.; Ollila, A.M.; Wiseman, S.M.; Roush, T.L.; Marzo, G.A.; Tornabene, L.L.; Okubo, C.H.; Osterloo, M.M.; Hamilton, V.E.; Crumpler, L.S.

    2010-01-01

    Morphological features on the western floor of Miyamoto crater in southwestern Meridiani Planum, Mars, are suggestive of past fluvial activity. Imagery from the High Resolution Imaging Science Experiment (HiRISE) gives a detailed view of raised curvilinear features that appear to represent inverted paleochannel deposits. The inverted terrain appears to be capped with a resistant, dark-toned deposit that is partially covered by unconsolidated surficial materials. Subsequent to deposition of the capping layer, erosion of the surrounding material has left the capping materials perched on pedestals of uneroded basal unit material. Neither the capping material nor the surrounding terrains show any unambiguous morphological evidence of volcanism or glaciation. The capping deposit may include unconsolidated or cemented stream deposits analogous to terrestrial inverted channels in the Cedar Mountain Formation near Green River, Utah. In addition to this morphological evidence for fluvial activity, phyllosilicates have been identified in the basal material on the floor of Miyamoto crater by orbital spectroscopy, providing mineralogical evidence of past aqueous activity. Based on both the morphological and mineralogical evidence, Miyamoto crater represents an excellent site for in situ examination and sampling of a potentially habitable environment. ?? 2009 Elsevier Inc.

  10. Noise from Supersonic Coaxial Jets. Part 3; Inverted Velocity Profile

    NASA Technical Reports Server (NTRS)

    Dahl, Milo D.; Morris, Philip J.

    1997-01-01

    The instability wave noise generation model is used to study the instability waves in the two shear layers of an inverted velocity profile, supersonic, coaxial jet and the noise radiated from the dominant wave. The inverted velocity profile jet has a high speed outer stream surrounding a low speed inner stream and the outer shear layer is always larger than the inner shear layer. The jet mean flows are calculated numerically. The operating conditions are chosen to exemplify the effect of the coaxial jet outer shear layer initial spreading rates. Calculations are made for the stability characteristics in the coaxial jet shear layers and the noise radiated from the instability waves for different operating conditions with the same total thrust, mass flow and exit area as a single reference jet. Results for inverted velocity profile jets indicate that relative maximum instability wave amplitudes and far field peak noise levels can be reduced from that of the reference jet by having higher spreading rates for the outer shear layer, low velocity ratios, and outer streams hotter than the inner stream.

  11. Orbifold E-functions of dual invertible polynomials

    NASA Astrophysics Data System (ADS)

    Ebeling, Wolfgang; Gusein-Zade, Sabir M.; Takahashi, Atsushi

    2016-08-01

    An invertible polynomial is a weighted homogeneous polynomial with the number of monomials coinciding with the number of variables and such that the weights of the variables and the quasi-degree are well defined. In the framework of the search for mirror symmetric orbifold Landau-Ginzburg models, P. Berglund and M. Henningson considered a pair (f , G) consisting of an invertible polynomial f and an abelian group G of its symmetries together with a dual pair (f ˜ , G ˜) . We consider the so-called orbifold E-function of such a pair (f , G) which is a generating function for the exponents of the monodromy action on an orbifold version of the mixed Hodge structure on the Milnor fibre of f. We prove that the orbifold E-functions of Berglund-Henningson dual pairs coincide up to a sign depending on the number of variables and a simple change of variables. The proof is based on a relation between monomials (say, elements of a monomial basis of the Milnor algebra of an invertible polynomial) and elements of the whole symmetry group of the dual polynomial.

  12. Inverted rank distributions: Macroscopic statistics, universality classes, and critical exponents

    NASA Astrophysics Data System (ADS)

    Eliazar, Iddo; Cohen, Morrel H.

    2014-01-01

    An inverted rank distribution is an infinite sequence of positive sizes ordered in a monotone increasing fashion. Interlacing together Lorenzian and oligarchic asymptotic analyses, we establish a macroscopic classification of inverted rank distributions into five “socioeconomic” universality classes: communism, socialism, criticality, feudalism, and absolute monarchy. We further establish that: (i) communism and socialism are analogous to a “disordered phase”, feudalism and absolute monarchy are analogous to an “ordered phase”, and criticality is the “phase transition” between order and disorder; (ii) the universality classes are characterized by two critical exponents, one governing the ordered phase, and the other governing the disordered phase; (iii) communism, criticality, and absolute monarchy are characterized by sharp exponent values, and are inherently deterministic; (iv) socialism is characterized by a continuous exponent range, is inherently stochastic, and is universally governed by continuous power-law statistics; (v) feudalism is characterized by a continuous exponent range, is inherently stochastic, and is universally governed by discrete exponential statistics. The results presented in this paper yield a universal macroscopic socioeconophysical perspective of inverted rank distributions.

  13. Linear Synchronous Motor Repeatability Tests

    SciTech Connect

    Ward, C.R.

    2002-10-18

    A cart system using linear synchronous motors was being considered for the Plutonium Immobilization Plant (PIP). One of the applications in the PIP was the movement of a stack of furnace trays, filled with the waste form (pucks) from a stacking/unstacking station to several bottom loaded furnaces. A system was ordered to perform this function in the PIP Ceramic Prototype Test Facility (CPTF). This system was installed and started up in SRTC prior to being installed in the CPTF. The PIP was suspended and then canceled after the linear synchronous motor system was started up. This system was used to determine repeatability of a linear synchronous motor cart system for the Modern Pit Facility.

  14. Asymmetric Preorganization of Inverted Pair Residues in the Sodium-Calcium Exchanger

    PubMed Central

    Giladi, Moshe; Almagor, Lior; van Dijk, Liat; Hiller, Reuben; Man, Petr; Forest, Eric; Khananshvili, Daniel

    2016-01-01

    In analogy with many other proteins, Na+/Ca2+ exchangers (NCX) adapt an inverted twofold symmetry of repeated structural elements, while exhibiting a functional asymmetry by stabilizing an outward-facing conformation. Here, structure-based mutant analyses of the Methanococcus jannaschii Na+/Ca2+ exchanger (NCX_Mj) were performed in conjunction with HDX-MS (hydrogen/deuterium exchange mass spectrometry) to identify the structure-dynamic determinants of functional asymmetry. HDX-MS identified hallmark differences in backbone dynamics at ion-coordinating residues of apo-NCX_Mj, whereas Na+or Ca2+ binding to the respective sites induced relatively small, but specific, changes in backbone dynamics. Mutant analysis identified ion-coordinating residues affecting the catalytic capacity (kcat/Km), but not the stability of the outward-facing conformation. In contrast, distinct “noncatalytic” residues (adjacent to the ion-coordinating residues) control the stability of the outward-facing conformation, but not the catalytic capacity. The helix-breaking signature sequences (GTSLPE) on the α1 and α2 repeats (at the ion-binding core) differ in their folding/unfolding dynamics, while providing asymmetric contributions to transport activities. The present data strongly support the idea that asymmetric preorganization of the ligand-free ion-pocket predefines catalytic reorganization of ion-bound residues, where secondary interactions with adjacent residues couple the alternating access. These findings provide a structure-dynamic basis for ion-coupled alternating access in NCX and similar proteins. PMID:26876271

  15. Direct and inverted reciprocal chromosome insertions between chromosomes 7 and 14 in a woman with recurrent miscarriages

    SciTech Connect

    Ying-Tai Wang; Zhao-Cai Wang; Bajalica, S.; Han, F.Y.; Bui, T.H.; Xie, Y.G.

    1994-09-01

    We present the first case of direct and inverted reciprocal chromosome insertions between human chromosomes 7 and 14, ascertained because of repeated spontaneous abortions. Prometaphase GTG banding analysis showed the karyotype to be 46, XX, inv ins (7;14)(7pter {yields} 7q11.23::14q32.2 {yields} 14q22::7q21.2 {yields} 7qter), dir ins(14;7)(14pter {yields} 14q22::7q11.23 {yields} 7q21.2::14q32.2 {yields} 14qter). Origins of the insertion have been confirmed by chromosome painting with libraries specific for chromosomes 7 and 14 using fluorescence in situ hybridization. 5 refs., 3 figs.

  16. R2R-printed inverted OPV modules - towards arbitrary patterned designs

    NASA Astrophysics Data System (ADS)

    Välimäki, M.; Apilo, P.; Po, R.; Jansson, E.; Bernardi, A.; Ylikunnari, M.; Vilkman, M.; Corso, G.; Puustinen, J.; Tuominen, J.; Hast, J.

    2015-05-01

    We describe the fabrication of roll-to-roll (R2R) printed organic photovoltaic (OPV) modules using gravure printing and rotary screen-printing processes. These two-dimensional printing techniques are differentiating factors from coated OPVs enabling the direct patterning of arbitrarily shaped and sized features into visual shapes and, increasing the freedom to connect the cells in modules. The inverted OPV structures comprise five layers that are either printed or patterned in an R2R printing process. We examined the rheological properties of the inks used and their relationship with the printability, the compatibility between the processed inks, and the morphology of the R2R-printed layers. We also evaluate the dimensional accuracy of the printed pattern, which is an important consideration in designing arbitrarily-shaped OPV structures. The photoactive layer and top electrode exhibited excellent cross-dimensional accuracy corresponding to the designed width. The transparent electron transport layer extended 300 µm beyond the designed values, whereas the hole transport layer shrank 100 µm. We also examined the repeatability of the R2R fabrication process when the active area of the module varied from 32.2 cm2 to 96.5 cm2. A thorough layer-by-layer optimization of the R2R printing processes resulted in realization of R2R-printed 96.5 cm2 sized modules with a maximum power conversion efficiency of 2.1% (mean 1.8%) processed with high functionality.

  17. Trinucleotide Repeats: A Structural Perspective

    PubMed Central

    Almeida, Bruno; Fernandes, Sara; Abreu, Isabel A.; Macedo-Ribeiro, Sandra

    2013-01-01

    Trinucleotide repeat (TNR) expansions are present in a wide range of genes involved in several neurological disorders, being directly involved in the molecular mechanisms underlying pathogenesis through modulation of gene expression and/or the function of the RNA or protein it encodes. Structural and functional information on the role of TNR sequences in RNA and protein is crucial to understand the effect of TNR expansions in neurodegeneration. Therefore, this review intends to provide to the reader a structural and functional view of TNR and encoded homopeptide expansions, with a particular emphasis on polyQ expansions and its role at inducing the self-assembly, aggregation and functional alterations of the carrier protein, which culminates in neuronal toxicity and cell death. Detail will be given to the Machado-Joseph Disease-causative and polyQ-containing protein, ataxin-3, providing clues for the impact of polyQ expansion and its flanking regions in the modulation of ataxin-3 molecular interactions, function, and aggregation. PMID:23801983

  18. Observations of Soft Gamma Repeaters

    NASA Technical Reports Server (NTRS)

    Kouveliotou, Chryssa

    2005-01-01

    Magnetars (Soft Gamma Repeaters and Anomalous X-ray Pulsars) are a subclass of neutron stars characterized by their recurrent X-ray bursts. While in an active (bursting) state (lasting anywhere between days and years), they are emitting hundreds of predominantly soft (kl'=30 kev), short (0.1 - 100 ms long) events. Their quiescent source X-ray light curves exhibit pulsations in the narrow range of 5-1 1 s; estimates of these rotational period rate changes (spin-down) indicate that their magnetic fields are extremely high, of the order of 10A14-10A15 G. Such high B-field objects, dubbed "magnetars", had been predicted to exist in 1992, but the first concrete observational evidence was obtained in 1998 for two of these sources. Very recently, SGR1806-20 emitted a giant flare, which was detected in the radio with a multitude of telescopes under an extensive international campaign. These observations have revealed exciting new results, never seen before in any of the other magnetar sources. I will discuss here these results and their relevance to our understanding of the nature of magnetars.

  19. Modeling Repeatedly Flaring δ Sunspots.

    PubMed

    Chatterjee, Piyali; Hansteen, Viggo; Carlsson, Mats

    2016-03-11

    Active regions (ARs) appearing on the surface of the Sun are classified into α, β, γ, and δ by the rules of the Mount Wilson Observatory, California on the basis of their topological complexity. Amongst these, the δ sunspots are known to be superactive and produce the most x-ray flares. Here, we present results from a simulation of the Sun by mimicking the upper layers and the corona, but starting at a more primitive stage than any earlier treatment. We find that this initial state consisting of only a thin subphotospheric magnetic sheet breaks into multiple flux tubes which evolve into a colliding-merging system of spots of opposite polarity upon surface emergence, similar to those often seen on the Sun. The simulation goes on to produce many exotic δ sunspot associated phenomena: repeated flaring in the range of typical solar flare energy release and ejective helical flux ropes with embedded cool-dense plasma filaments resembling solar coronal mass ejections. PMID:27015469

  20. Repeated Sprints: An Independent Not Dependent Variable.

    PubMed

    Taylor, Jonathan M; Macpherson, Tom W; Spears, Iain R; Weston, Matthew

    2016-07-01

    The ability to repeatedly perform sprints has traditionally been viewed as a key performance measure in team sports, and the relationship between repeated-sprint ability (RSA) and performance has been explored extensively. However, when reviewing the repeated-sprint profile of team-sports match play it appears that the occurrence of repeated-sprint bouts is sparse, indicating that RSA is not as important to performance as commonly believed. Repeated sprints are, however, a potent and time-efficient training strategy, effective in developing acceleration, speed, explosive leg power, aerobic power, and high-intensity-running performance--all of which are crucial to team-sport performance. As such, we propose that repeated-sprint exercise in team sports should be viewed as an independent variable (eg, a means of developing fitness) as opposed to a dependent variable (eg, a means of assessing fitness/performance). PMID:27197118

  1. Strengthening concept learning by repeated testing

    PubMed Central

    Wiklund-Hörnqvist, Carola; Jonsson, Bert; Nyberg, Lars

    2014-01-01

    The aim of this study was to examine whether repeated testing with feedback benefits learning compared to rereading of introductory psychology key-concepts in an educational context. The testing effect was examined immediately after practice, after 18 days, and at a five-week delay in a sample of undergraduate students (n = 83). The results revealed that repeated testing with feedback significantly enhanced learning compared to rereading at all delays, demonstrating that repeated retrieval enhances retention compared to repeated encoding in the short- and the long-term. In addition, the effect of repeated testing was beneficial for students irrespectively of working memory capacity. It is argued that teaching methods involving repeated retrieval are important to consider by the educational system. PMID:24313425

  2. Motor/Generator and Inverter Characterization for Flywheel System Applications

    NASA Technical Reports Server (NTRS)

    Tamarcus, Jeffries L.

    2004-01-01

    The Advanced Electrical Systems Development Branch at NASA Glenn Research Center (GRC) has been involved in the research and development of high speed flywheels systems for satellite energy storage and attitude applications. These flywheels will serve as replacement for chemical nickel hydrogen, nickel cadmium batteries and gyroscopic wheels. The advantages of using flywheel systems for energy storage on satellites are high energy density, high power density, long life, deep depth of discharge, and broad operating temperature ranges. A flywheel system for space applications consist of a number of flywheel modules, the motor/generator and magnetic bearing, and an electronics package. The motor/generator electronics package includes a pulse-width modulated inverter that drives the flywheel permanent magnet motor/generator located at one end of the shaft. This summer, I worked under the direct supervision of my mentor, Walter Santiago, and the goal for this summer was to characterize motor generator and inverter attributes in order to increase their viability as a more efficient energy storage source for space applications. To achieve this goal, magnetic field measurements around the motor/generator permanent magnet and the impedance of the motor/generator three phase windings were characterized, and a recreation of the inverter pulse width modulated control system was constructed. The Flywheel modules for space use are designed to maximize energy density and minimize loss, and attaining these values will aid in locating and reducing losses within the flywheel system as a whole, making flywheel technology more attractive for use as energy storage in future space applications.

  3. Himalayan inverted metamorphism constrained by oxygen isotope thermometry

    NASA Astrophysics Data System (ADS)

    Vannay, Jean-Claude; Sharp, Zachary D.; Grasemann, Bernhard

    Inverted metamorphic field gradients are preserved in two amphibolite facies metapelitic sequences forming the crystalline core zone of the Himalayan orogen in the Sutlej valley (NW India). In the High Himalayan Crystalline Sequence (HHCS), metamorphic conditions increase upwards from the staurolite zone at the base, through the kyanite-in and sillimanite-in isograds, finally to reach partial melting conditions at the top. The structurally lower Lesser Himalayan Crystalline Sequence (LHCS) shows a gradual superposition of garnet-in, staurolite-in and kyanite+sillimanite-in isograds. Although phase equilibria constraints imply inverted temperature field gradients in both units, garnet-biotite (GARB) rim thermometry indicates final equilibration at a nearly uniform temperature around T 600°C across these sequences. The P-T path and garnet zoning data show that this apparent lack of thermal field gradient is mainly the consequence of a resetting of the GARB equilibria during cooling. In order to constrain peak temperature conditions, 20 samples along the studied section have been analysed for oxygen isotope thermometry. The isotopic fractionations recorded by quartz-garnet and quartz-aluminosilicate mineral pairs indicate temperatures consistent with phase equilibria and P-T path constraints for metamorphic peak conditions. Together with barometry results, based on net transfer continuous reactions, the oxygen isotope thermometry indicates peak conditions characterized by: (1) a temperature increase from T 570 to 750°C at a nearly constant pressure around P 800MPa, from the base to the top of the HHCS unit; (2) a temperature increase from T 610 to 700°C and a pressure decrease from P 900 to 700MPa, from the base to the top of the LHCS metapelites. Oxygen isotope thermometry thus provides the first quantitative data demonstrating that the Himalayan inverted metamorphism can be associated with a complete inversion of the thermal field gradient across the crystalline

  4. Daily Full-Disk SOLIS Inverted Vector Magnetic Field Data

    NASA Astrophysics Data System (ADS)

    Streander, Kim; Norton, A. A.; SOLIS Team

    2009-05-01

    Inverted vector magnetic field data from the SOLIS VSM (Synoptic Optical Long-term Investigations of the Sun Vector Spectromagnetograph) instrument are now available at:http://solis.nso.edu/. Both full-disk and smaller field-of-view data containing active regions are available. The inversion is based on the least-squares minimization FORTRAN code developed by the HAO group, initially used with Advanced Stokes Polarimeter data (Skumanich and Lites, 1987; Auer, Heasley and House, 1977). The main code modification is that a scattered light, or quiet-Sun profile, is simulated for every center-to-limb position on the disk. This simulated profile is used as the scattered light profile, instead of an observed profile averaged from pixels with low polarization within a small field of view. The data are inversions of Stokes I, Q, U and V profiles of the Fe I 630.1 and 630.2 nm lines using a Milne-Eddington (ME) model atmosphere. Stokes I, Q, U and V profile weights are 0.01, 1.0, 1.0 and 0.1, respectively. All the Milne-Eddington inverted data are corrected for the 180º ambiguity using the Non-Potential Field Calculation (NPFC) method developed by Manolis Georgoulis (Johns Hopkins). Note that data are only inverted if the observed polarization signal is above a certain threshold.Data are available daily (weather permitting) beginning April 1, 2009 onwards. Also available is a sample of data from March 2008 containing several active regions near the equator.

  5. Short Tandem Repeat DNA Internet Database

    National Institute of Standards and Technology Data Gateway

    SRD 130 Short Tandem Repeat DNA Internet Database (Web, free access)   Short Tandem Repeat DNA Internet Database is intended to benefit research and application of short tandem repeat DNA markers for human identity testing. Facts and sequence information on each STR system, population data, commonly used multiplex STR systems, PCR primers and conditions, and a review of various technologies for analysis of STR alleles have been included.

  6. Understanding and identifying amino acid repeats.

    PubMed

    Luo, Hong; Nijveen, Harm

    2014-07-01

    Amino acid repeats (AARs) are abundant in protein sequences. They have particular roles in protein function and evolution. Simple repeat patterns generated by DNA slippage tend to introduce length variations and point mutations in repeat regions. Loss of normal and gain of abnormal function owing to their variable length are potential risks leading to diseases. Repeats with complex patterns mostly refer to the functional domain repeats, such as the well-known leucine-rich repeat and WD repeat, which are frequently involved in protein–protein interaction. They are mainly derived from internal gene duplication events and stabilized by ‘gate-keeper’ residues, which play crucial roles in preventing inter-domain aggregation. AARs are widely distributed in different proteomes across a variety of taxonomic ranges, and especially abundant in eukaryotic proteins. However, their specific evolutionary and functional scenarios are still poorly understood. Identifying AARs in protein sequences is the first step for the further investigation of their biological function and evolutionary mechanism. In principle, this is an NP-hard problem, as most of the repeat fragments are shaped by a series of sophisticated evolutionary events and become latent periodical patterns. It is not possible to define a uniform criterion for detecting and verifying various repeat patterns. Instead, different algorithms based on different strategies have been developed to cope with different repeat patterns. In this review, we attempt to describe the amino acid repeat-detection algorithms currently available and compare their strategies based on an in-depth analysis of the biological significance of protein repeats. PMID:23418055

  7. Extreme Cost Reductions with Multi-Megawatt Centralized Inverter Systems

    SciTech Connect

    Schwabe, Ulrich; Fishman, Oleg

    2015-03-20

    The objective of this project was to fully develop, demonstrate, and commercialize a new type of utility scale PV system. Based on patented technology, this includes the development of a truly centralized inverter system with capacities up to 100MW, and a high voltage, distributed harvesting approach. This system promises to greatly impact both the energy yield from large scale PV systems by reducing losses and increasing yield from mismatched arrays, as well as reduce overall system costs through very cost effective conversion and BOS cost reductions enabled by higher voltage operation.

  8. Electrical characterization of a Mapham inverter using pulse testing techniques

    NASA Technical Reports Server (NTRS)

    Baumann, E. D.; Myers, I. T.; Hammoud, A. N.

    1990-01-01

    The use of a multiple pulse testing technique to determine the electrical characteristics of large megawatt-level power systems for aerospace missions is proposed. An innovative test method based on the multiple pulse technique is demonstrated on a 2-kW Mapham inverter. The concept of this technique shows that characterization of large power systems under electrical equilibrium at rated power can be accomplished without large costly power supplies. The heat generation that occurs in systems when tested in a continuous mode is eliminated. The results indicate that there is a good agreement between this testing technique and that of steady state testing.

  9. Separation of simple sugars by selectivity inverted parametric pumping

    SciTech Connect

    Sheng, P.; Costa, C.A.V.

    1998-12-01

    An alternative process to separate the isomeric mixture of fructose and glucose is presented. A laboratory study of a two-column, selectivity inverted, direct-mode parametric pump is reported. An anionic resin in carbonate form and a cationic resin in calcium form are used as adsorbents for the columns. The experimental results show that it is possible to simultaneously obtain separation and concentration with this system. A kinetic model assuming linear equilibrium, intraparticle pore diffusion, and axial dispersion is proposed and solved. The model solutions are compared with experimental results, and the comparisons indicate good prediction capabilities.

  10. Inverters for interfacing of solar cells with the power grid

    NASA Astrophysics Data System (ADS)

    Karamanzanis, G. N.; Jackson, R. D.

    In this work, based on a research course in the Engineering Dep. Cambridge University, some non-classical inverter circuits are studied. They can be used for interfacing solar cells with the power grid at low voltage (230V) and at low power level. They are based on d.c. choppers which have a fast switching transistor. Their theoretical efficiency is 100 percent and they provide a satisfactory output current waveform in phase to the a.c. line voltage. The problems of control are also studied using a suitable mathematical model.

  11. Inverted Takotsubo cardiomyopathy after attempted suicidal hanging--two cases.

    PubMed

    Sengupta, Shantanu; Mungulmare, Kunda; Wadaskar, Nitin; Pande, Abhishek

    2016-04-01

    We report two cases of "Inverted Takotsubo cardiomyopathy" following attempted suicidal hanging. Both the patients presented with heart failure and had desaturation 8-12h after the suicidal attempt. Electrocardiography (ECG) showed ischemic changes. On echocardiography, the left ventricle (LV) showed ballooning and hypokinesia of the basal segments with apical sparing. Both patients underwent coronary angiograms considering the possibility of acute coronary syndrome. However, their coronary angiograms were normal. After 3-4 days of hospitalization, both recovered; their ECG had reversed and the LV contractility was normal on echocardiography. PMID:27056654

  12. Molecular solid-state inverter-converter system

    NASA Technical Reports Server (NTRS)

    Birchenough, A. G.

    1973-01-01

    A modular approach for aerospace electrical systems has been developed, using lightweight high efficiency pulse width modulation techniques. With the modular approach, a required system is obtained by paralleling modules. The modular system includes the inverters and converters, a paralleling system, and an automatic control and fault-sensing protection system with a visual annunciator. The output is 150 V dc, or a low distortion three phase sine wave at 120 V, 400 Hz. Input power is unregulated 56 V dc. Each module is rated 2.5 kW or 3.6 kVA at 0.7 power factor.

  13. Displacement measurement system for inverters using computer micro-vision

    NASA Astrophysics Data System (ADS)

    Wu, Heng; Zhang, Xianmin; Gan, Jinqiang; Li, Hai; Ge, Peng

    2016-06-01

    We propose a practical system for noncontact displacement measurement of inverters using computer micro-vision at the sub-micron scale. The measuring method of the proposed system is based on a fast template matching algorithm with an optical microscopy. A laser interferometer measurement (LIM) system is built up for comparison. Experimental results demonstrate that the proposed system can achieve the same performance as the LIM system but shows a higher operability and stability. The measuring accuracy is 0.283 μm.

  14. Naturally Inspired Firefly Controller For Stabilization Of Double Inverted Pendulum

    NASA Astrophysics Data System (ADS)

    Srikanth, Kavirayani; Nagesh, Gundavarapu

    2015-12-01

    A double inverted pendulum plant as an established model that is analyzed as part of this work was tested under the influence of time delay, where the controller was fine tuned using a firefly algorithm taking into considering the fitness function of variation of the cart position and to minimize the cart position displacement and still stabilize it effectively. The naturally inspired algorithm which imitates the fireflies definitely is an energy efficient method owing to the inherent logic of the way the fireflies respond collectively and has shown that critical time delays makes the system healthy.

  15. Design and analysis of controllers for a double inverted pendulum.

    PubMed

    Niemann, Henrik; Poulsen, Jesper Kildegaard

    2005-01-01

    A physical control problem is studied with the Hinfinity, and the micro methodology. The issues of modeling, uncertainty modeling, performance specification, controller design, and laboratory implementation are discussed. The laboratory experiment is a double inverted pendulum placed on a cart. The limitations in the system with respect to performance are the limitation in the control signal and the limitation of the movement of the cart. It is shown how these performance limitations will effect the design of Hinfinity and micro controllers for the system. PMID:15682623

  16. Electrical characterization of a Mapham inverter using pulse testing techniques

    NASA Astrophysics Data System (ADS)

    Baumann, E. D.; Myers, I. T.; Hammoud, A. N.

    The use of a multiple pulse testing technique to determine the electrical characteristics of large megawatt-level power systems for aerospace missions is proposed. An innovative test method based on the multiple pulse technique is demonstrated on a 2-kW Mapham inverter. The concept of this technique shows that characterization of large power systems under electrical equilibrium at rated power can be accomplished without large costly power supplies. The heat generation that occurs in systems when tested in a continuous mode is eliminated. The results indicate that there is a good agreement between this testing technique and that of steady state testing.

  17. Characterization of the Ecosole HCPV tracker and single module inverter

    NASA Astrophysics Data System (ADS)

    Carpanelli, Maurizio; Borelli, Gianni; Verdilio, Daniele; De Nardis, Davide; Migali, Fabrizio; Cancro, Carmine; Graditi, Giorgio

    2015-09-01

    BECAR, the Beghelli group's R&D company, is leading ECOSOLE (Elevated COncentration SOlar Energy), one of the largest European Demonstration projects in solar photovoltaic. ECOSOLE, started in 2012, is focused on the study, design, and realization of new HCPV generator made of high efficiency PV modules equipped with SoG (Silicone on Glass) fresnel lenses and III-V solar cells, and a low cost matched solar tracker with distributed inverters approach. The project also regards the study and demonstration of new high throughput methods for the industrial large scale productions, at very low manufacturing costs. This work reports the description of the characterization of the tracker and single module.

  18. Robust sliding mode control applied to double Inverted pendulum system

    SciTech Connect

    Mahjoub, Sonia; Derbel, Nabil; Mnif, Faical

    2009-03-05

    A three hierarchical sliding mode control is presented for a class of an underactuated system which can overcome the mismatched perturbations. The considered underactuated system is a double inverted pendulum (DIP), can be modeled by three subsystems. Such structure allows the construction of several designs of hierarchies for the controller. For all hierarchical designs, the asymptotic stability of every layer sliding mode surface and the sliding mode surface of subsystems are proved theoretically by Barbalat's lemma. Simulation results show the validity of these methods.

  19. Lambda Exonuclease Digestion of CGG Trinucleotide Repeats

    PubMed Central

    Conroy, R.S.; Koretsky, A.P.; Moreland, J.

    2011-01-01

    Fragile X syndrome and other triplet repeat diseases are characterized by an elongation of a repeating DNA triplet. The ensemble-averaged lambda exonuclease digestion rate of different substrates, including one with an elongated FMR1 gene containing 120 CGG repeats, was measured using absorption and fluorescence spectroscopy. Using magnetic tweezers sequence-dependent digestion rates and pausing was measured for individual lambda exonucleases. Within the triplet repeats a lower average and narrower distribution of rates and a higher frequency of pausing was observed. PMID:19562332

  20. Approaching improved adhesive bonding repeatability

    NASA Astrophysics Data System (ADS)

    Schlette, Christian; Müller, Tobias; Roβmann, Jürgen; Brecher, Christian

    2016-03-01

    Today, the precision of micro-optics assembly is mostly limited by the accuracy of the bonding process ― and in the case of adhesive bonding by the prediction and compensation of adhesive shrinkage during curing. In this contribution, we present a novel approach to address adhesive bonding based on hybrid control system theory. In hybrid control, dynamic systems are described as "plants" which produce discrete and/or continuous outputs from given discrete and/or continuous inputs, thus yielding a hybrid state space description of the system. The task of hybrid controllers is to observe the plant and to generate a discrete and/or continuous input sequence that guides or holds the plant in a desired target state region while avoiding invalid or unwanted intermediate states. Our approach is based on a series of experiments carried out in order to analyze, define and decouple the dependencies of adhesive shrinkage on multiple parameters, such as application geometries, fixture forces and UV intensities. As some of the dependencies describe continuous effects (e.g. shrinkage from UV intensity) and other dependencies describe discrete state transitions (e.g. fixture removal during curing), the resulting model of the overall bonding process is a hybrid dynamic system in the general case. For this plant model, we then propose a concept of sampling-based parameter search as a basis to design suitable hybrid controllers, which have the potential to optimize process control for a selection of assembly steps, thus improving the repeatability of related production steps like beam-shaping optics or mounting of turning mirrors for fiber coupling.

  1. Utility-scale grid-tied PV inverter reliability workshop summary report.

    SciTech Connect

    Granata, Jennifer E.; Quintana, Michael A.; Tasca, Coryne Adelle; Atcitty, Stanley

    2011-07-01

    A key to the long-term success of the photovoltaic (PV) industry is confidence in the reliability of PV systems. Inverters are the most commonly noted cause of PV system incidents triggered in the field. While not all of these incidents are reliability-related or even necessarily failures, they still result in a loss of generated power. With support from the U.S. Department of Energy's Solar Energy Technologies Program, Sandia National Laboratories organized a Utility-Scale Grid-Tied Inverter Reliability Workshop in Albuquerque, New Mexico, January 27-28, 2011. The workshop addressed the reliability of large (100-kilowatt+) grid-tied inverters and the implications when such inverters fail, evaluated inverter codes and standards, and provided discussion about opportunities to enhance inverter reliability. This report summarizes discussions and presentations from the workshop and identifies opportunities for future efforts.

  2. High-speed all-optical logic inverter based on stimulated Raman scattering in silicon nanocrystal.

    PubMed

    Sen, Mrinal; Das, Mukul K

    2015-11-01

    In this paper, we propose a new device architecture for an all-optical logic inverter (NOT gate), which is cascadable with a similar device. The inverter is based on stimulated Raman scattering in silicon nanocrystal waveguides, which are embedded in a silicon photonic crystal structure. The Raman response function of silicon nanocrystal is evaluated to explore the transfer characteristic of the inverter. A maximum product criterion for the noise margin is taken to analyze the cascadability of the inverter. The time domain response of the inverter, which explores successful inversion operation at 100 Gb/s, is analyzed. Propagation delay of the inverter is on the order of 5 ps, which is less than the delay in most of the electronic logic families as of today. Overall dimension of the device is around 755  μm ×15  μm, which ensures integration compatibility with the matured silicon industry. PMID:26560565

  3. Evaluation of quasi-square wave inverter as a power source for induction motors

    NASA Technical Reports Server (NTRS)

    Guynes, B. V.; Haggard, R. L.; Lanier, J. R., Jr.

    1977-01-01

    The relative merits of quasi-square wave inverter-motor technology versus a sine wave inverter-motor system were investigated. The empirical results of several tests on various sizes of wye-wound induction motors are presented with mathematical analysis to support the conclusions of the study. It was concluded that, within the limitations presented, the quasi-square wave inverter-motor system is superior to the more complex sine wave system for most induction motor applications in space.

  4. Screening protocol for iodine-specific getters in YMP-related invert applications.

    SciTech Connect

    Krumhansl, James Lee; Pless, Jason; Chwirka, J. Benjamin

    2006-07-01

    This document defines a standardized screening protocol for use in developing iodine ''getters'' for placement in the proposed YMP-repository invert. The work was funded by the US Department of Energy (DOE), Office of Civilian Radioactive Waste Management (OCRWM), Office of Science and Technology International (S&T) during 2004-2005. First, the likely environmental conditions in the invert are reviewed as a basis for defining the thermal and geochemical regimes in which a getter must function. These considerations, then, served as the basis for laying out a hierarchy of materials screening tests (Table 1). An experimental design for carrying out these screening tests follows next. Finally, the latter half of the document develops methods for preparing test solutions with chemistries that relate to various aspects of the YMP-repository environment (or, at least to such representations as were available from program documents late in 2004). Throughout the document priority was given to defining procedures that would quickly screen out unpromising candidate materials with a minimum amount of labor. Hence, the proposed protocol relies on batch tests over relatively short times, and on a hierarchy of short pre-test conditioning steps. So as not to repeat the mistakes (and frustrations) encountered in the past (notably in preparing WIPP test brines) particular care was also given to developing standardized test solution recipes that could be prepared easily and reproducibly. This document is principally intended for use as a decision-making tool in evaluating and planning research activities. It is explicitly NOT a roadmap for qualifying getters for actual placement in the repository. That would require a comprehensive test plan and a substantial consensus building effort. This document is also not intended to provide a complete list of all the tests that individuals may wish to carry out. Various materials will have their own peculiar concerns that will call for

  5. Screening Protocol for Iodine-Specific Getters in YMP-Related Invert Applications

    SciTech Connect

    J.L. Krumhansl; J.D. Pless; J.B. Chwirka

    2006-07-17

    This document defines a standardized screening protocol for use in developing iodine ''getters'' for placement in the proposed YMP-repository invert. The work was funded by the US Department of Energy (DOE), Office of Civilian Radioactive Waste Management (OCRWM), Office of Science and Technology International (S&T) during 2004-2005. First, the likely environmental conditions in the invert are reviewed as a basis for defining the thermal and geochemical regimes in which a getter must function. These considerations, then, served as the basis for laying out a hierarchy of materials screening tests (Table 1). An experimental design for carrying out these screening tests follows next. Finally, the latter half of the document develops methods for preparing test solutions with chemistries that relate to various aspects of the YMP-repository environment (or, at least to such representations as were available from program documents late in 2004). Throughout the document priority was given to defining procedures that would quickly screen out unpromising candidate materials with a minimum amount of labor. Hence, the proposed protocol relies on batch tests over relatively short times, and on a hierarchy of short pre-test conditioning steps. So as not to repeat the mistakes (and frustrations) encountered in the past (notably in preparing WIPP test brines) particular care was also given to developing standardized test solution recipes that could be prepared easily and reproducibly. This document is principally intended for use as a decision-making tool in evaluating and planning research activities. It is explicitly NOT a roadmap for qualifying getters for actual placement in the repository. That would require a comprehensive test plan and a substantial consensus building effort. This document is also not intended to provide a complete list of all the tests that individuals may wish to carry out. Various materials will have their own peculiar concerns that will call for

  6. Examining cemented inverted channel deposits in Green River, Utah as an analog for inverted terrain on Mars

    NASA Astrophysics Data System (ADS)

    Lanza, N.; Okubo, C. H.; Rampe, E. B.; Ollila, A. M.; Newsom, H. E.; Yurchyk, S.

    2009-12-01

    There have been numerous observations of long, relatively sinuous, positive relief landforms on Mars that appear morphologically similar to inverted channel deposits (ICDs) on Earth that represent exhumed fluvial sediments. ICDs initially form as bed sediments within active stream channels that subsequently become cemented, commonly by carbonates, iron oxides, or amorphous silica precipitated during evaporation. Subsequent deflation by aeolian processes reveals these sediments as positive relief features. Features such as the putative delta system in Eberswalde crater and the sinuous ridge in Miyamoto crater appear morphologically similar to terrestrial ICDs. The goal of this study is to better understand how terrestrial ICDs appear to remote sensing instruments that are similar to the ones currently orbiting Mars, and whether they have morphologic or spectroscopic characteristics that could help to identify them from orbit as paleofluvial deposits. Specifically, the presence of cement materials in conjunction with inverted terrain may help to identify potential ICDs on Mars. While carbonate is an unlikely cementing agent on Mars, both iron oxide and amorphous silica have been observed there. A terrestrial analog may be found in ICDs in the Cedar Mountain formation in Green River, Utah. Preliminary electron microprobe results indicate that the cement in these ICDs is primarily an amorphous silica (chalcedony) rather than a carbonate. If some martian inverted features are similarly cemented, they may not initially appear to be sedimentary features in infrared (IR) spectroscopy remote sensing data, especially if their constituent sediments are basaltic. We will show results from our initial laboratory examination of terrestrial ICD samples in mid-IR emission spectroscopy and compare these with remote sensing data of these ICDs in a similar band range from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) to identify features characteristic of

  7. Multiple output power supply circuit for an ion engine with shared upper inverter

    NASA Technical Reports Server (NTRS)

    Cardwell, Jr., Gilbert I. (Inventor); Phelps, Thomas K. (Inventor)

    2001-01-01

    A power supply circuit for an ion engine suitable for a spacecraft is coupled to a bus having a bus input and a bus return. The power supply circuit has a first primary winding of a first transformer. An upper inverter circuit is coupled to the bus input and the first primary winding. The power supply circuit further includes a first lower inverter circuit coupled to the bus return and the first primary winding. The second primary winding of a second transformer is coupled to the upper inverter circuit. A second lower inverter circuit is coupled to the bus return and the second primary winding.

  8. [Effect of the interphase surface charge on the structure and activity of trypsin in inverted micelles].

    PubMed

    Valiullina, Iu A; Stupishina, E A; Vylegzhanina, N N; Idiiatullin, B Z; Zuev, Iu F

    2008-01-01

    The effect of the sign and value of the charge of the interphase surface on the catalytic activity of trypsin in systems of inverted mycelles was investigated. n-Butanol was used for the modification of the phase interface in dispersions of inverted mycelles based on anionic sodium bis(2-ethylhexyl)sulfosuccinate (AOT) and cationic cetyltrimethylammonium bromide (CTAB). A direct correlation between changes in the state of inverted mycelles and the structure of solubilized enzyme under the action of butanol was obtained. It was shown that the enzyme activity is determined by the quantity of butanol solubilized by the inverted mycelles. PMID:18672691

  9. A region of euchromatin coincides with an extensive tandem repeat on the mouse (Mus musculus) inactive X chromosome.

    PubMed

    Darrow, Emily M; Seberg, Andrew P; Das, Sunny; Figueroa, Debbie M; Sun, Zhuo; Moseley, Shawn C; Chadwick, Brian P

    2014-09-01

    Euchromatic features are largely absent from the human inactive X chromosome (Xi), with the exception of several large tandem repeats that can be detected as euchromatin bands at metaphase. Despite residing megabases apart, these tandem repeats make frequent inactive X-specific interactions. The mouse homologue has been reported for at least one of the tandem repeats, but whether the mouse Xi is also characterized by distinct bands of euchromatin remains unknown. We examined the mouse Xi for the presence of euchromatin bands by examining the pattern of histone H3 dimethylated at lysine 4 and detected two major signals. The first band resides in the subtelomeric region of band XF5 and may correspond to the pseudoautosomal region. The second band localizes to XE3 and coincides with an extensive complex repeat composed of a large tandem and inverted repeat segment as well as several large short interspersed nuclear element (SINE)-rich tandem repeats. Fluorescence in situ hybridization reveals that sequences with homology to the repeat region are scattered along the length of the Y chromosome. Immunofluorescence analysis of histone H3 trimethylated at lysine 9 on metaphase chromosomes indicates that the repeat region corresponds to a band of constitutive heterochromatin on the male X and female active X chromosomes, whereas the euchromatin signal appears to be female specific. These data suggest that the band of euchromatin observed at XE3 is unique to the mouse Xi, comparable to the chromatin arrangement of several large tandem repeats located on the human X chromosome. PMID:24821208

  10. All Repeats are Not Equal: A Module-Based Approach to Guide Repeat Protein Design

    PubMed Central

    Regan, Lynne

    2013-01-01

    Repeat proteins composed of tandem arrays of a short structural motif often mediate protein-protein interactions. Past efforts to design repeat protein-based molecular recognition tools have focused on the creation of templates from the consensus of individual repeats, regardless of their natural context. Such an approach assumes that all repeats are essentially equivalent. In this study we present the results of a ‘module-based’ approach, in which modules composed of tandem repeats are aligned to identify repeat-specific features. Using this approach to analyze tetratricopeptide repeat modules that contain 3 tandem repeats (3TPRs), we identify two classes of 3TPR modules with distinct structural signatures that are correlated with different sets of functional residues. Our analyses also reveal a high degree of correlation between positions across the entire ligand-binding surface, indicative of a coordinated, coevolving binding surface. Extension of our analyses to different repeat protein modules reveals more examples of repeat-specific features, especially in armadillio repeat (ARM) modules. In summary, the module-based analyses that we present effectively capture key repeat-specific features that will be important to include in future repeat protein design templates. PMID:23434848

  11. Amphoteric water-in-oil self-inverting polymer emulsion

    SciTech Connect

    Lipowski, S. A.; Miskel Jr., J. J.

    1985-03-19

    An amphoteric water-in-oil self-inverting polymer emulsion is prepared which contains a copolymer of a nonionic vinyl monomer and an amphoteric vinyl monomer or a terpolymer of (1) a nonionic vinyl monomer, an anionic vinyl monomer and a cationic vinyl monomer in the aqueous phase, a hydrocarbon oil for the oil phase, a water-in-oil emulsifying agent and an inverting surfactant. An example of a copolymer is a copolymer of a nonionic vinyl monomer such as acrylamide or methacrylamide and an amphoteric vinyl monomer such as a reaction product of dimethylaminoethyl methacrylate and monochloroacetic acid. An example of a terpolymer is a terpolymer of a nonionic vinyl monomer such as acrylamide or methacrylamide, an anionic vinyl monomer such as sodium acrylate and a cationic vinyl monomer such as a triethyl ammonium ethyl methacrylate methosulfate salt. The emulsion is useful in papermaking, treatment of sewage and industrial wastes, drilling muds and secondary and tertiary recovery of petroleum by water flooding.

  12. Liking versus Complexity: Decomposing the Inverted U-curve

    PubMed Central

    Güçlütürk, Yağmur; Jacobs, Richard H. A. H.; van Lier, Rob

    2016-01-01

    The relationship between liking and stimulus complexity is commonly reported to follow an inverted U-curve. However, large individual differences among complexity preferences of participants have frequently been observed since the earliest studies on the topic. The common use of across-participant analysis methods that ignore these large individual differences in aesthetic preferences gives an impression of high agreement between individuals. In this study, we collected ratings of liking and perceived complexity from 30 participants for a set of digitally generated grayscale images. In addition, we calculated an objective measure of complexity for each image. Our results reveal that the inverted U-curve relationship between liking and stimulus complexity comes about as the combination of different individual liking functions. Specifically, after automatically clustering the participants based on their liking ratings, we determined that one group of participants in our sample had increasingly lower liking ratings for increasingly more complex stimuli, while a second group of participants had increasingly higher liking ratings for increasingly more complex stimuli. Based on our findings, we call for a focus on the individual differences in aesthetic preferences, adoption of alternative analysis methods that would account for these differences and a re-evaluation of established rules of human aesthetic preferences. PMID:27047359

  13. Unstable high molecular weight inverted repetitive DNA in human lymphocytes.

    PubMed Central

    Rogers, J C; Rucinsky, T E

    1982-01-01

    About 1% of newly synthesized DNA from PHA-stimulated human lymphocytes can be isolated as large (up to 90 kilobase pairs) double stranded fragments that resist sequential alkali and heat denaturation steps but are not closed circular. By electron microscopy about 1% have single-strand hairpin loops at one end and therefore present inverted repetitive sequences (IR-DNA). Most of the remainder have a blunt-appearing double-strand terminus at both ends (78%) or one end (18%). Indirect evidence indicates that these also are inverted complementary structures with terminal hairpin loops too small to be visualized: (1) Treatment with either a 5' or 3' single-strand exonuclease generates essentially only fragments with a single strand at one end; (2) with partial denaturation, the number of fragments with identifiable single-strand hairpin loops increases (to about 20%); (3) after S1 nuclease digestion, greater than 95% can be fully heat denatured. Cot analysis indicates that these fragments are derived from dispersed sites throughout the genome. Up to 25% of DNA released from lymphocytes during growth similarly resists denaturation, and released DNA and IR-DNA are both enriched in the same set of repetitive sequences. Thus at least a portion of IR-DNA appears to be unstable. Images PMID:7145706

  14. The management of sinonasal inverted papilloma: our experience.

    PubMed

    Terzakis, Georgios; Vlachou, Stamatia; Kyrmizakis, Dionysios; Helidonis, Emmanuel

    2002-03-01

    The inverted papilloma of the nose and paranasal sinuses is a controversial disease. It invades surrounded structures, shows a high recurrence rate after surgical excision and may coexist with squamous cell carcinoma. The use of the optimal surgical approach and technique is of the utmost importance, as it is related to the possibility of recurrence. In cases of tumors of limited size a conservative local excision is sufficient, while, in larger tumors filling the nasal cavity and the paranasal sinuses a more aggressive strategy is needed, such as a medial maxillectomy after lateral rhinotomy. In this paper we present our experience from treating 42 sinonasal inverted papillomas, using a surgical technique which is based on the conservation of as much part of the healthy lateral nasal wall as possible. This modified medial maxillectomy allows us to create a limited in size and normally functioning nasal cavity, thus minimizing the disadvantages of the classical medial maxillectomy without jeopardizing the safety of the operation. PMID:12012951

  15. Fast face recognition by using an inverted index

    NASA Astrophysics Data System (ADS)

    Herrmann, Christian; Beyerer, Jürgen

    2015-02-01

    This contribution addresses the task of searching for faces in large video datasets. Despite vast progress in the field, face recognition remains a challenge for uncontrolled large scale applications like searching for persons in surveillance footage or internet videos. While current productive systems focus on the best shot approach, where only one representative frame from a given face track is selected, thus sacrificing recognition performance, systems achieving state-of-the-art recognition performance, like the recently published DeepFace, ignore recognition speed, which makes them impractical for large scale applications. We suggest a set of measures to address the problem. First, considering the feature location allows collecting the extracted features in according sets. Secondly, the inverted index approach, which became popular in the area of image retrieval, is applied to these feature sets. A face track is thus described by a set of local indexed visual words which enables a fast search. This way, all information from a face track is collected which allows better recognition performance than best shot approaches and the inverted index permits constantly high recognition speeds. Evaluation on a dataset of several thousand videos shows the validity of the proposed approach.

  16. On the wake dynamics of flapping inverted flags

    NASA Astrophysics Data System (ADS)

    Gilmanov, Anvar; Sotiropoulos, Fotis; Cosse, Julia; Gharib, Mory

    2014-11-01

    As recently shown experimentally by Kim et al. (JFM, 2013), when a flexible flag with a fixed trailing edge (an inverted flag) is exposed to a uniform inflow it can exhibit complex structural response and rich fluid-structure interaction (FSI) dynamics. We employ a new FSI numerical method to carry out large-eddy simulation (LES) of inverted flags in the range where large-amplitude flapping instabilities have been found experimentally. The numerical method integrates the curvilinear immersed boundary (CURVIB) FSI method of Borazjani et al. (JCP, 2008) with the thin-shell, rotation-free, finite-element (FE) formulation of Stolarski et al. (Int. JNME, 2013) and is able to simulate FSI of flexible thin bodies undergoing oscillations of arbitrarily large amplitude. The dynamic Smagorinsky model is employed for subgrid scale closure and a wall model is employed for reconstructing velocity boundary conditions. Comparisons with the experimental data show that the simulations are able to capture the structural response of the flag with very good accuracy. The computed results are analyzed to elucidate the structure and dynamics of the massively separated, unsteady flow shed off the flag edges. This work is supported by the US Department of Energy and the Minnesota Supercomputing Institute.

  17. Vigilance and task load - In search of the inverted U

    NASA Technical Reports Server (NTRS)

    Wiener, E. L.; Curry, R. E.; Faustina, M. L.

    1984-01-01

    The 'Inverted-U Hypothesis' states that for a given task, there is an optimal level of workload or demand that yields the highest level of performance. A departure in either direction will result in a monotonically lower performance level, hence an inverted-U-shaped relationship between task demand and quality of performance. Most studies to date have failed to demonstrate the left-hand branch of the curve, that is, the regime in which performance presumably rises as load increases. The purpose of this study was to explore whether low-level additional demand on the monitor would result in improved performance. Four groups of subjects performed a visual monitoring task for 48 min, then two of the four groups were given additional tasks, and a third had potentially distracting information on its display. Results indicated that the two groups with additional demand detected more signals than did the control group or the control-plus-distraction group. There were no significant differences in false alarms.

  18. High-power, null-type, inverted pendulum thrust stand.

    PubMed

    Xu, Kunning G; Walker, Mitchell L R

    2009-05-01

    This article presents the theory and operation of a null-type, inverted pendulum thrust stand. The thrust stand design supports thrusters having a total mass up to 250 kg and measures thrust over a range of 1 mN to 5 N. The design uses a conventional inverted pendulum to increase sensitivity, coupled with a null-type feature to eliminate thrust alignment error due to deflection of thrust. The thrust stand position serves as the input to the null-circuit feedback control system and the output is the current to an electromagnetic actuator. Mechanical oscillations are actively damped with an electromagnetic damper. A closed-loop inclination system levels the stand while an active cooling system minimizes thermal effects. The thrust stand incorporates an in situ calibration rig. The thrust of a 3.4 kW Hall thruster is measured for thrust levels up to 230 mN. The uncertainty of the thrust measurements in this experiment is +/-0.6%, determined by examination of the hysteresis, drift of the zero offset and calibration slope variation. PMID:19485530

  19. Activation of Spinal Stabilizers and Shoulder Complex Muscles During an Inverted Row Using a Portable Pull-up Device and Body Weight Resistance.

    PubMed

    Youdas, James W; Keith, Julianne M; Nonn, Danielle E; Squires, Adam C; Hollman, John H

    2016-07-01

    Youdas, JW, Keith, JM, Nonn, DE, Squires, AC, and Hollman, JH. Activation of spinal stabilizers and shoulder complex muscles during an inverted row using a portable pull-up device and body weight resistance. J Strength Cond Res 30(7): 1933-1941, 2016-We recorded muscle activation normalized to a maximum voluntary isometric contraction (% MVIC) during an inverted body weight row using a commercially available portable pull-up device. Surface electromyographic (EMG) analysis was conducted on 13 male and 13 female subjects performing 4 inverted row exercises: (a) pronated grip both feet weight-bearing (WB); (b) supinated grip both feet WB; (c) pronated grip one leg WB; and (d) supinated grip single-leg WB. Nine muscles were analyzed: (a) posterior deltoid (PD), (b) latissimus dorsi (LD), (c) biceps brachii (BB), (d) lower trapezius (LT), (e) upper trapezius (UT), (f) lumbar multifidus (LM), (g) middle trapezius (MT), (h) lumbar thoracis (LTh), and (i) rectus abdominis (RA). Normalized peak EMG activity was examined separately for each muscle with 9 repeated measures analysis of variance (ANOVA) at α = 0.05. Post hoc comparisons of EMG activation across exercises for statistically significant ANOVAs were conducted with Bonferroni corrections for multiple comparisons. We observed statistically significant differences in EMG activation of the LD between supinated and pronated double-leg WB (p = 0.001) condition. Additionally, we found statistical significance in the UT between pronated and supinated single-leg WB (p = 0.007). No statistically significant differences in muscle activation existed between single- and double-leg WB in any muscles. Four muscles (BB, LD, LT, and PD) demonstrated very high (>61% MVIC) EMG activation during all 4 exercise conditions. Three muscles (UT, MT, and LM) demonstrated high (41-60% MVIC) activation, whereas 2 muscles (LTh and RA) demonstrated moderate (21-40% MVIC) activation. Four inverted row exercises activated the LD, UT, MT, LT

  20. 47 CFR 97.205 - Repeater station.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES AMATEUR RADIO SERVICE Special Operations § 97.205 Repeater station. (a) Any amateur station licensed to a holder of a Technician, General, Advanced or Amateur Extra Class operator license may be a repeater. A holder of...

  1. 47 CFR 97.205 - Repeater station.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES AMATEUR RADIO SERVICE Special Operations § 97.205 Repeater station. (a) Any amateur station licensed to a holder of a Technician, General, Advanced or Amateur Extra Class operator license may be a repeater. A holder of...

  2. 47 CFR 97.205 - Repeater station.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES AMATEUR RADIO SERVICE Special Operations § 97.205 Repeater station. (a) Any amateur station licensed to a holder of a Technician, General, Advanced or Amateur Extra Class operator license may be a repeater. A holder of...

  3. 47 CFR 97.205 - Repeater station.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES AMATEUR RADIO SERVICE Special Operations § 97.205 Repeater station. (a) Any amateur station licensed to a holder of a Technician, General, Advanced or Amateur Extra Class operator license may be a repeater. A holder of...

  4. 47 CFR 97.205 - Repeater station.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES AMATEUR RADIO SERVICE Special Operations § 97.205 Repeater station. (a) Any amateur station licensed to a holder of a Technician, General, Advanced or Amateur Extra Class operator license may be a repeater. A holder of...

  5. The Effects of Repeaters on Test Equating.

    ERIC Educational Resources Information Center

    Andrulis, Richard S.; And Others

    The purpose of this investigation was to establish the effects of repeaters on test equating. Since consideration was not given to repeaters in test equating, such as in the derivation of equations by Angoff (1971), the hypothetical effect needed to be established. A case study was examined which showed results on a test as expected; overall mean…

  6. The Effects of Repeaters on Test Equating.

    ERIC Educational Resources Information Center

    Andrulis, Richard S.; And Others

    1978-01-01

    The effects of repeaters (testees included in both administrations of two forms of a test) on the test equating process are examined. It is shown that repeaters do effect test equating and tend to lower the cutoff point for passing the test. (JKS)

  7. Evaluating a Group Repeated Reading Intervention

    ERIC Educational Resources Information Center

    Klubnik, Cynthia Adele

    2009-01-01

    Fluency has been identified as an important component of effective reading instruction, and repeated reading has been shown to improve oral reading fluency. In order to improve the efficiency of repeated reading interventions, more research is needed on the effectiveness of small group reading interventions. An alternating treatments, single…

  8. Laparoscopic repeat hepatectomy after right hepatopancreaticoduodenectomy.

    PubMed

    Igami, Tsuyoshi; Komaya, Kenichi; Hirose, Tomoaki; Ebata, Tomoki; Yokoyama, Yukihiro; Sugawara, Gen; Mizuno, Takashi; Yamaguchi, Junpei; Nagino, Masato

    2016-08-01

    Although laparoscopic hepatectomy is widely accepted for primary hepatectomy, the clinical value of laparoscopic hepatectomy for repeat hepatectomy is still challenging. We herein describe our experience with laparoscopic repeat hepatectomy after right hepatopancreaticoduodenectomy. A 72-year-old woman who had undergone right hepatopancreaticoduodenectomy for perihilar cholangiocarcinoma 31 months prior was diagnosed with liver metastasis in segment 3. We performed laparoscopic repeat hepatectomy. Because mild adhesions in the left side of the abdominal cavity were detected by laparoscopy, the planned procedure was accomplished. The operative time and intraoperative blood loss were 139 min and less than 1 mL, respectively. The patient was discharged at 6 days after surgery and was healthy with no evidence of recurrence at 21 months after laparoscopic repeat hepatectomy. Laparoscopic repeat hepatectomy is a suitable and safe procedure for minor hepatectomy, provided that careful technique is used after the working space is secured under pneumoperitoneum. PMID:27221034

  9. Repeated Testing Produces Superior Transfer of Learning Relative to Repeated Studying

    ERIC Educational Resources Information Center

    Butler, Andrew C.

    2010-01-01

    The present research investigated whether test-enhanced learning can be used to promote transfer. More specifically, 4 experiments examined how repeated testing and repeated studying affected retention and transfer of facts and concepts. Subjects studied prose passages and then either repeatedly restudied or took tests on the material. One week…

  10. Improved Tunnel-FET inverter performance with SiGe/Si heterostructure nanowire TFETs by reduction of ambipolarity

    NASA Astrophysics Data System (ADS)

    Richter, S.; Trellenkamp, S.; Schäfer, A.; Hartmann, J. M.; Bourdelle, K. K.; Zhao, Q. T.; Mantl, S.

    2015-06-01

    Complementary MOSFET and Tunnel-FET inverters based on tri-gated strained Si nanowire arrays are demonstrated. The voltage transfer characteristics as well as the inverter supply currents of both inverter types are analyzed and compared. A degradation of the inverter output voltage is observed due to the ambipolar transfer characteristics of the symmetric homostructure TFET devices. Emulated TFET inverters based on the measured transfer characteristics of SiGe/Si heterostructure nanowire array n-channel TFETs with reduced ambipolarity demonstrate improved inverter switching for supply voltages down to VDD = 0.2 V.

  11. Single phase inverter for a three phase power generation and distribution system

    NASA Technical Reports Server (NTRS)

    Lindena, S. J.

    1976-01-01

    A breadboard design of a single-phase inverter with sinusoidal output voltage for a three-phase power generation and distribution system was developed. The three-phase system consists of three single-phase inverters, whose output voltages are connected in a delta configuration. Upon failure of one inverter the two remaining inverters will continue to deliver three-phase power. Parallel redundancy as offered by two three-phase inverters is substituted by one three-phase inverter assembly with high savings in volume, weight, components count and complexity, and a considerable increase in reliability. The following requirements must be met: (1) Each single-phase, current-fed inverter must be capable of being synchronized to a three-phase reference system such that its output voltage remains phaselocked to its respective reference voltage. (2) Each single-phase, current-fed inverter must be capable of accepting leading and lagging power factors over a range from -0.7 through 1 to +0.7.

  12. Evaluation tests of Abacus 6 kVA utility-interactive inverter

    NASA Astrophysics Data System (ADS)

    Landsman, E. E.

    1981-08-01

    The voltage pattern spectra were analyzed for 100% and 50% pattern ratios and harmonics analyses are provided for the Abacus inverter. The harmonics are compared with those calculated for a simple model with no agreement. AC waveforms and inverter current spectra are given as well as basic electrical data.

  13. Evaluation tests of Abacus 6 kVA utility-interactive inverter

    SciTech Connect

    Landsman, E.E.

    1981-08-01

    The voltage pattern spectra were analyzed for 100% and 50% pattern ratios and harmonics analyses are provided for the Abacus inverter. The harmonics are compared with those calculated for a simple model with no agreement. AC waveforms and inverter current spectra are given as well as basic electrical data. (LEW)

  14. Vortex dynamics and flapping patterns of the inverted flag with a bluff body

    NASA Astrophysics Data System (ADS)

    Kim, Hyeonseong; Kim, Junyoung; Kim, Daegyoum

    2015-11-01

    Flow-induced vibration of flexible structures for energy harvesting has drawn attention recently. The inverted flag whose trailing edge is clamped and leading edge is free to move was known to self-excite in a uniform flow of both water and air. In this study, we investigated the effect of an upstream bluff body, a flat plate, on the dynamics of the downstream inverted flag. Periodic vortical structures created by an upstream bluff body make the dynamics of the inverted flag quite different from those of the inverted flag without the bluff body. We examined the motion of the inverted flag by varying the relative displacement of the inverted flag from the bluff body and their relative size. Our results show that the inverted flag can flap with higher frequency and larger amplitude with the upstream bluff body. We also compared the dynamics of the inverted flag with those of the general flag with the upstream bluff body. In order to better understand the dynamics of the flag, the analysis of the flow patterns using particle image velocimetry was also conducted.

  15. Inverting Instruction in Literacy Methods Courses: Making Learning More Active and Personalized

    ERIC Educational Resources Information Center

    Zawilinski, Lisa M.; Richard, Kimberly A.; Henry, Laurie A.

    2016-01-01

    Three teacher educators who inverted/flipped instruction in their literacy courses describe their experience in this article. Inverted, or flipped, instruction is a blended learning approach that increases opportunities for active engagement in class by moving basic instructor demonstration and presentation outside of class. The authors provide a…

  16. Inverting the Classroom: A Gateway to Creating an Inclusive Learning Environment.

    ERIC Educational Resources Information Center

    Lage, Maureen J.; Platt, Glenn J.; Treglia, Michael

    2000-01-01

    Describes a teaching strategy called the inverted classroom that enables instructors of introductory economics courses to address students' different learning styles within the time constraints of the class. Explains that in the inverted classroom the events that traditionally take place during class time now take place outside the classroom and…

  17. Design of An Inverted Magnetron Gun for a High Power Gyroklystron

    NASA Astrophysics Data System (ADS)

    Read, Michael E.; Nusinovich, Gregory; Ives, R. Lawrence

    2003-12-01

    A magnetron injection gun (MIG) with an inverted geometry is described. Use of an inverted geometry with the inner electrode at ground potential provides support for the inner coax portion of the cavities of a high power gyroklystron, and results in improved optics. The geometry of the gun is described and results of trajectory simulations are presented.

  18. A single-phase embedded Z-source DC-AC inverter.

    PubMed

    Kim, Se-Jin; Lim, Young-Cheol

    2014-01-01

    In the conventional DC-AC inverter consisting of two DC-DC converters with unipolar output capacitors, the output capacitor voltages of the DC-DC converters must be higher than the DC input voltage. To overcome this weakness, this paper proposes a single-phase DC-AC inverter consisting of two embedded Z-source converters with bipolar output capacitors. The proposed inverter is composed of two embedded Z-source converters with a common DC source and output AC load. Though the output capacitor voltages of the converters are relatively low compared to those of a conventional inverter, an equivalent level of AC output voltages can be obtained. Moreover, by controlling the output capacitor voltages asymmetrically, the AC output voltage of the proposed inverter can be higher than the DC input voltage. To verify the validity of the proposed inverter, experiments were performed with a DC source voltage of 38 V. By controlling the output capacitor voltages of the converters symmetrically or asymmetrically, the proposed inverter can produce sinusoidal AC output voltages. The experiments show that efficiencies of up to 95% and 97% can be achieved with the proposed inverter using symmetric and asymmetric control, respectively. PMID:25133241

  19. A Single-Phase Embedded Z-Source DC-AC Inverter

    PubMed Central

    Kim, Se-Jin; Lim, Young-Cheol

    2014-01-01

    In the conventional DC-AC inverter consisting of two DC-DC converters with unipolar output capacitors, the output capacitor voltages of the DC-DC converters must be higher than the DC input voltage. To overcome this weakness, this paper proposes a single-phase DC-AC inverter consisting of two embedded Z-source converters with bipolar output capacitors. The proposed inverter is composed of two embedded Z-source converters with a common DC source and output AC load. Though the output capacitor voltages of the converters are relatively low compared to those of a conventional inverter, an equivalent level of AC output voltages can be obtained. Moreover, by controlling the output capacitor voltages asymmetrically, the AC output voltage of the proposed inverter can be higher than the DC input voltage. To verify the validity of the proposed inverter, experiments were performed with a DC source voltage of 38 V. By controlling the output capacitor voltages of the converters symmetrically or asymmetrically, the proposed inverter can produce sinusoidal AC output voltages. The experiments show that efficiencies of up to 95% and 97% can be achieved with the proposed inverter using symmetric and asymmetric control, respectively. PMID:25133241

  20. Status and Needs of Power Electronics for Photovoltaic Inverters: Summary Document

    SciTech Connect

    WEST, RICK; MAUCH, KONRAD; QIN,YU CHIN; MOHAN,NED; BONN, RUSSELL H.

    2002-04-01

    Photovoltaic inverters are the most mature of any DER inverter, and their mean time to first failure (MTFF) is about five years. This is an unacceptable MTFF and will inhibit the rapid expansion of PV. With all DER technologies, (solar, wind, fuel cells, and microturbines) the inverter is still an immature product that will result in reliability problems in fielded systems. The increasing need for all of these technologies to have a reliable inverter provides a unique opportunity to address these needs with focused R&D development projects. The requirements for these inverters are so similar that modular designs with universal features are obviously the best solution for a ''next generation'' inverter. A ''next generation'' inverter will have improved performance, higher reliability, and improved profitability. Sandia National Laboratories has estimated that the development of a ''next generation'' inverter could require approximately 20 man-years of work over an 18- to 24-month time frame, and that a government-industry partnership will greatly improve the chances of success.

  1. Inverted Teaching: Applying a New Pedagogy to a University Organic Chemistry Class

    ERIC Educational Resources Information Center

    Christiansen, Michael A.

    2014-01-01

    Inverted teaching, not to be confused with hybrid learning, is a relatively new pedagogy in which lecture is shifted outside of class and traditional homework is done in class. Though some inverted teaching (IT) designs have been published in different fields, peer-reviewed reports in university chemistry remain quite rare. To that end, herein is…

  2. Do gamma-ray burst sources repeat?

    NASA Technical Reports Server (NTRS)

    Meegan, C. A.; Hartmann, D. H.; Brainerd, J. J.; Briggs, M.; Paciesas, W. S.; Pendleton, G.; Kouveliotou, C.; Fishman, G.; Blumenthal, G.; Brock, M.

    1994-01-01

    The demonstration of repeated gamma-ray bursts from an individual source would severely constrain burst source models. Recent reports of evidence for repetition in the first BATSE burst catalog have generated renewed interest in this issue. Here, we analyze the angular distribution of 585 bursts of the second BATSE catalog (Meegan et al. 1994). We search for evidence of burst recurrence using the nearest and farthest neighbor statistic ad the two-point angular correlation function. We find the data to be consistent with the hypothesis that burst sources do not repeat; however, a repeater fraction of up to about 20% of the bursts cannot be excluded.

  3. Expression analysis for inverted effects of serotonin transporter inactivation

    SciTech Connect

    Ichikawa, Manabu |; Okamura-Oho, Yuko Shimokawa, Kazuro; Kondo, Shinji; Nakamura, Sakiko; Yokota, Hideo |; Himeno, Ryutaro; Lesch, Klaus-Peter; Hayashizaki, Yoshihide |

    2008-03-28

    Inactivation of serotonin transporter (HTT) by pharmacologically in the neonate or genetically increases risk for depression in adulthood, whereas pharmacological inhibition of HTT ameliorates symptoms in depressed patients. The differing role of HTT function during early development and in adult brain plasticity in causing or reversing depression remains an unexplained paradox. To address this we profiled the gene expression of adult Htt knockout (Htt KO) mice and HTT inhibitor-treated mice. Inverted profile changes between the two experimental conditions were seen in 30 genes. Consistent results of the upstream regulatory element search and the co-localization search of these genes indicated that the regulation may be executed by Pax5, Pax7 and Gata3, known to be involved in the survival, proliferation, and migration of serotonergic neurons in the developing brain, and these factors are supposed to keep functioning to regulate downstream genes related to serotonin system in the adult brain.

  4. Position and Orientation Control of a Wheeled Inverted Pendulum

    NASA Astrophysics Data System (ADS)

    Ozaki, Hiroaki; Ohgushi, Takahiro; Shimogawa, Tetsuji; Lin, Chang-Jun

    A wheeled inverted pendulum (WIP), which is unstable, nonholonomic, and has two servo-driven wheels, is fabricated and used to confirm the proposed method for controlling its position and orientation. First, a WIP control system equipped with sensors such as a piezoelectric gyro to detect the tilt angle and two semiconductor photosensing devices to detect the position and orientation, is constructed. By using a distance variable, the system dynamics is decoupled and an optimal regulator with integral action is constructed to reduce the influence of disturbances. Algorithms are proposed to cope with the singularity problem included in the feedback control. Finally, the WIP is effectively controlled starting from various initial positions and orientations to a specified final state.

  5. Alpha detection in pipes using an inverting membrane scintillator

    SciTech Connect

    Kendrick, D.T.; Cremer, C.D.; Lowry, W.

    1995-10-01

    Characterization of surface alpha emitting contamination inside enclosed spaces such as piping systems presents an interesting radiological measurement challenge. Detection of these alpha particles from the exterior of the pipe is impossible since the alpha particles are completely absorbed by the pipe wall. Traditional survey techniques, using hand-held instruments, simply can not be used effectively inside pipes. Science and Engineering Associates, Inc. is currently developing an enhancement to its Pipe Explorer{trademark} system that will address this challenge. The Pipe Explorer{trademark} uses a unique sensor deployment method where an inverted tubular membrane is propagated through complex pipe runs via air pressure. The inversion process causes the membrane to fold out against the pipe wall, such that no part of the membrane drags along the pipe wall. This deployment methodology has been successfully demonstrated at several DOE sites to transport specially designed beta and gamma, scintillation detectors into pipes ranging in length up to 250 ft.

  6. Magnetic properties of superconductors with an inverted distribution

    SciTech Connect

    Idlis, B.G.; Kopaev, Y.V.

    1980-12-01

    A study is made of a semiconductor with an inverted distribution of quasiparticles created by external pumping. For pumping rates above a threshold value, a superconducting state may be created due to the electron--electron repulsion and such a state exhibits ideal paramagnetism rather than the Meissner effect. The fluctuation correction to the magnetic susceptibility is calculated for pumping levels below the threshold and it is shown that this correction is also paramagnetic and diverges as (..mu../sub c/-..mu..)/sup -1/2/ at the threshold (..mu.. is the chemical potential of nonequilibrium particles). The possibility of insulating pairing of nonequilibrium electrons and holes in such systems is also taken into account (for congruent Fermi surfaces) and it is shown that it does not affect the magnetic susceptibility of either the normal or superconducting phases. The transport properties of such systems are also briefly discussed.

  7. Quantum spin Hall effect in inverted type-II semiconductors.

    PubMed

    Liu, Chaoxing; Hughes, Taylor L; Qi, Xiao-Liang; Wang, Kang; Zhang, Shou-Cheng

    2008-06-13

    The quantum spin Hall (QSH) state is a topologically nontrivial state of quantum matter which preserves time-reversal symmetry; it has an energy gap in the bulk, but topologically robust gapless states at the edge. Recently, this novel effect has been predicted and observed in HgTe quantum wells and in this Letter we predict a similar effect arising in Type-II semiconductor quantum wells made from InAs/GaSb/AlSb. The quantum well exhibits an "inverted" phase similar to HgTe/CdTe quantum wells, which is a QSH state when the Fermi level lies inside the gap. Due to the asymmetric structure of this quantum well, the effects of inversion symmetry breaking are essential. Remarkably, the topological quantum phase transition between the conventional insulating state and the quantum spin Hall state can be continuously tuned by the gate voltage, enabling quantitative investigation of this novel phase transition. PMID:18643529

  8. Integrated Ring Oscillators based on high-performance Graphene Inverters

    PubMed Central

    Schall, Daniel; Otto, Martin; Neumaier, Daniel; Kurz, Heinrich

    2013-01-01

    The road to the realization of complex integrated circuits based on graphene remains an open issue so far. Current graphene based integrated circuits are limited by low integration depth and significant doping variations, representing major road blocks for the success of graphene in future electronic devices. Here we report on the realization of graphene based integrated inverters and ring oscillators. By using an optimized process technology for high-performance graphene transistors with local back-gate electrodes we demonstrate that complex graphene based integrated circuits can be manufactured reproducibly, circumventing problems associated with doping variations. The fabrication process developed here is scalable and fully compatible with conventional silicon technology. Therefore, our results pave the way towards applications based on graphene transistors in future electronic devices. PMID:24005257

  9. Complexity of regular invertible p-adic motions.

    PubMed

    Pettigrew, J.; Roberts, J. A. G.; Vivaldi, F.

    2001-12-01

    We consider issues of computational complexity that arise in the study of quasi-periodic motions (Siegel discs) over the p-adic integers, where p is a prime number. These systems generate regular invertible dynamics over the integers modulo p(k), for all k, and the main questions concern the computation of periods and orbit structure. For a specific family of polynomial maps, we identify conditions under which the cycle structure is determined solely by the number of Siegel discs and two integer parameters for each disc. We conjecture the minimal parametrization needed to achieve-for every odd prime p-a two-disc tessellation with maximal cycle length. We discuss the relevance of Cebotarev's density theorem to the probabilistic description of these dynamical systems. (c) 2001 American Institute of Physics. PMID:12779524

  10. An inverted crossover resonance aiding laser cooling of ^171Yb

    NASA Astrophysics Data System (ADS)

    McFerran, J. J.

    2016-06-01

    We observe an inverted crossover resonance in $\\pi$-driven four-level systems, where $F'-F=0,+1$. The signal is observed through saturated absorption spectroscopy of the $(6s^{2})$ $^{1}S_{0}$ $-$ $(6s6p)$ $^{3}P_{1}$ transition in $^{171}$Yb, where the nuclear spin $I=1/2$. The enhanced absorption signal is used to generate a dispersive curve for 556 nm laser frequency stabilisation and the stabilised light cools $^{171}$Yb atoms in a two-stage magneto-optical trap, achieving temperatures of 20 $\\mu$K. The Doppler-free spectroscopy scheme is further used to measure isotopic frequency shifts and hyperfine separations for the intercombination line in ytterbium.

  11. Phase synchronized quasiperiodicity in power electronic inverter systems

    NASA Astrophysics Data System (ADS)

    Zhusubaliyev, Zhanybai T.; Mosekilde, Erik; Andriyanov, Alexey I.; Shein, Vladimir V.

    2014-02-01

    The development of switch-mode operated power electronic converter systems has provided a broad range of new effective approaches to the conversion of electric power. In this paper we describe the transitions from regular periodic operation to quasiperiodicity and high-periodic resonance behavior that can be observed in a pulse-width modulated DC/AC converter operating with high feedback gain. We demonstrate the occurrence of two different types of torus birth bifurcations and present a series of phase portraits illustrating the appearance of phase-synchronized quasiperiodicity. Our numerical findings are verified through comparison with an experimental inverter system. The results shed light on the transitions to quasiperiodicity and to various forms of three-frequency dynamics in non-smooth systems.

  12. Low voltage drop plasma switch for inverter and modulator applications

    NASA Astrophysics Data System (ADS)

    Goebel, D. M.; Poeschel, R. L.; Schumacher, R. W.

    1993-08-01

    A low forward voltage drop plasma switch has been developed for high-efficiency inverter and modulator applications. The switch, called the HOLLOTRON, is based on a grid-controlled, thermionic hollow-cathode discharge. A low forward voltage drop (10-20 V) is achieved by operating the hollow-cathode discharge in a static gas pressure of xenon. The dense plasma generated in the Ba-oxide dispenser hollow cathode is spread over a relatively large control grid area by a diverging magnetic field superimposed on the discharge. Interruption of the discharge current at high current densities (≳4 A/cm2) over the grid area is achieved by biasing the control grid sufficiently negative with respect to the plasma. The HOLLOTRON switch has demonstrated voltage stand-off of up to 20 kV, switching times of ≤0.3 μs, and pulse repetition frequencies of 20 kHz at 50% duty.

  13. An Inverted Co-Flow Diffusion Flame for Producing Soot

    SciTech Connect

    Stipe, Christopher B.; Higgins, Brian S.; Lucas, Donald; Koshland, Catherine P.; Sawyer, Robert F.

    2005-06-21

    We developed an inverted, co-flow, methane/air/nitrogen burner that generates a wide range of soot particles sizes and concentrations. By adjusting the flow rates of air, methane, and nitrogen in the fuel, the mean electric mobility diameter and number concentration are varied. Additional dilution downstream of the flame allows us to generate particle concentrations spanning those produced by spark-ignited and diesel engines: particles with mean diameters between 50 and 250 nm and number concentrations from 4.7 {center_dot} 10{sup 4} to 10{sup 7} cm{sup -3}. The range of achievable number concentrations, and therefore volume concentrations, can be increased by a factor of 30 by reducing the dilution ratio. These operating conditions make this burner valuable for developing and calibrating diagnostics as well as for other studies involving soot particles.

  14. EV drivetrain inverter with V/HZ optimization

    DOEpatents

    Gritter, David J.; O'Neil, Walter K.

    1986-01-01

    An inverter (34) which provides power to an A.C. machine (28) is controlled by a circuit (36) employing PWM control strategy whereby A.C. power is supplied to the machine at a preselectable frequency and preselectable voltage. This is accomplished by the technique of waveform notching in which the shapes of the notches are varied to determine the average energy content of the overall waveform. Through this arrangement, the operational efficiency of the A.C. machine is optimized. The control circuit includes a micro-computer which calculates optimized machine control data signals from various parametric inputs and during steady state load conditions, seeks a best V/HZ ratio to minimize battery current drawn (system losses) from a D.C. power source (32). In the preferred embodiment, the present invention is incorporated within an electric vehicle (10) employing a 144 VDC battery pack and a three-phase induction motor (18).

  15. Electrical characterization of a Mapham inverter using pulse testing techniques

    NASA Technical Reports Server (NTRS)

    Baumann, E. D.; Myers, I. T.; Hammond, A. N.

    1990-01-01

    Electric power requirements for aerospace missions have reached megawatt power levels. Within the next few decades, it is anticipated that a manned lunar base, interplanetary travel, and surface exploration of the Martian surface will become reality. Several research and development projects aimed at demonstrating megawatt power level converters for space applications are currently underway at the NASA Lewis Research Center. Innovative testing techniques will be required to evaluate the components and converters, when developed, at their rated power in the absence of costly power sources, loads, and cooling systems. Facilities capable of testing these components and systems at full power are available, but their use may be cost prohibitive. The use of a multiple pulse testing technique is proposed to determine the electrical characteristics of large megawatt level power systems. Characterization of a Mapham inverter is made using the proposed technique and conclusions are drawn concerning its suitability as an experimental tool to evaluate megawatt level power systems.

  16. Upgrade of the inverted source of polarized electrons at ELSA

    NASA Astrophysics Data System (ADS)

    Heiliger, D.; Hillert, W.; Neff, B.

    2011-05-01

    Since 2000 an inverted source of polarized electrons at the electron stretcher accelerator ELSA routinely provides a pulsed beam with a polarization degree of about 80%. One micro-second long pulses with 100 nC charge are produced by irradiating a strained-layer superlattice photocathode with laser light from a flashlamp-pumped Ti:Sa laser. A rectangular pulse shape is achieved by operating the source in space charge limitation. The proposed hadron physics program requires an intensity upgrade to 200 mA which can be achieved by enlarging the emission area or by improving the quantum efficiency (QE). The resulting changes of the beam parameters (like emittance and space charge) and of the optics of the transfer line were investigated in numerical simulations. In order to enhance the source performance a new load lock system with crystal storage and atomic hydrogen cleaning will be installed in the near future.

  17. ELECTROSTATIC MODELING OF THE JEFFERSON LABORATORY INVERTED CERAMIC GUN

    SciTech Connect

    P. Evtushenko ,F.E. Hannon, C. Hernandez-Garcia

    2010-05-01

    Jefferson Laboratory (JLab) is currently developing a new 500kV DC electron gun for future use with the FEL. The design consists of two inverted ceramics which support a central cathode electrode. This layout allows for a load-lock system to be located behind the gun chamber. The electrostatic geometry of the gun has been designed to minimize surface electric field gradients and also to provide some transverse focusing to the electron beam during transit between the cathode and anode. This paper discusses the electrode design philosophy and presents the results of electrostatic simulations. The electric field information obtained through modeling was used with particle tracking codes to predict the effects on the electron beam.

  18. A case of gastric hamartomatous inverted polyp resected endoscopically

    PubMed Central

    Dohi, Moyu; Gen, Yasuyuki; Yoshioka, Mika

    2016-01-01

    We report the case of a 55-year-old woman with a tumor in the greater curvature of the upper gastric body. The tumor was incidentally found on an upper gastrointestinal X-ray series performed during a routine medical examination. Whereas endoscopy revealed a gastric submucosal tumor (SMT), endoscopic ultrasonography demonstrated a heterogeneous tumor with small, cystic, hypoechoic spots originating from the second layer. The patient was clinically asymptomatic, with no contributory family history or abnormal laboratory data. The results of a physical examination, abdominal computed tomography, and plain chest radiography were all unremarkable. Although the endoscopic tumor type was determined to be SMT, the tumor was successfully resected by endoscopic submucosal dissection (ESD) and subsequently diagnosed as a gastric hamartomatous inverted polyp (GHIP). The findings of the present case highlight the importance of considering GHIP as a diagnosis and indicate the utility of en bloc resection of GHIP with ESD. PMID:27556064

  19. Suspended-Patch Antenna With Inverted, EM-Coupled Feed

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.

    2004-01-01

    An improved suspended-patch antenna has been designed to operate at a frequency of about 23 GHz with linear polarization and to be one of four identical antennas in a rectangular array. The antenna includes a parasitic patch on top of a suspended dielectric superstrate, an active patch on top of a suspended dielectric substrate, a microstrip on the bottom of the dielectric substrate, and a ground plane. The microstrip, the ground plane, the airgap between them, and the dielectric substrate together constitute a transmission line that has an impedance of 50 Ohm and is electromagnetically (EM) coupled to the active patch. The parasitic patch is, in turn, excited by the active patch. The microstrip feed is characterized as inverted because the microstrip is on the bottom of the substrate, whereas microstrips are usually placed on the tops of dielectric substrates

  20. CMOS inverter design-hardened to the total dose effect

    SciTech Connect

    Roche, F.M.; Salager, L.

    1996-12-01

    This paper reports and discusses the experimental behavior of two inverter structures Rad-Hardened by Design to {sup 60}Co irradiation. The authors use the results on a set of basic circuits and transistors exposed to the same total doses as these structures to establish the effective formation conditions of the parasitic channel. Then this leakage evolution is related to the gate voltage history under irradiation. Finally, they take advantage of this intrinsic degradation property to propose a new Design Rad Hardened (DRH) cell. This structure considerably limits the Low Noise Margin degradation, helps to maintain the logic functionality with a High Output level and improves both the rad-tolerance and the static power consumption.

  1. Inverted Internal Limiting Membrane Flap For Large Traumatic Macular Holes.

    PubMed

    Abou Shousha, Mohsen Ahmed

    2016-01-01

    The aim of the study was to assess the role of inverted internal limiting membrane flap as a treatment option for large traumatic macular holes.This is a prospective noncomparative study in which 12 eyes with large traumatic macular holes (basal diameter of 1300-2800 μm) since 3 to 6 months were subjected to standard 23-gauge vitrectomy with removal of the posterior hyaloid, brilliant blue G (BBG)-assisted internal limiting membrane peeling in a circular fashion keeping it attached to the edge of the hole to create a flap. At the end of the surgery, air fluid exchange was done with inversion of the internal limiting membrane flap inside the macular hole using the soft tipped cannula and sulfur hexafluoride 20% as tamponade. The main follow-up measures are the best corrected visual acuity and the optical coherence tomography for 6 to 9 months.All the included eyes had a closed hole from the first week postoperative and along the follow-up period (6-9 months). The best corrected visual acuity improved from 20/2000 to 20/200 with a median of 20/400 preoperatively to 20/400 to 20/50 with a median of 20/100 at the end of follow-up period.Inverted internal limiting membrane flap is a good adjuvant to standard vitrectomy in the management of large traumatic macular holes that led to the 100% closure rate and improvement of best corrected visual acuity. PMID:26817894

  2. Analysis and modeling of a family of two-transistor parallel inverters

    NASA Technical Reports Server (NTRS)

    Lee, F. C. Y.; Wilson, T. G.

    1973-01-01

    A family of five static dc-to-square-wave inverters, each employing a square-loop magnetic core in conjunction with two switching transistors, is analyzed using piecewise-linear models for the nonlinear characteristics of the transistors, diodes, and saturable-core devices. Four of the inverters are analyzed in detail for the first time. These analyses show that, by proper choice of a frame of reference, each of the five quite differently appearing inverter circuits can be described by a common equivalent circuit. This equivalent circuit consists of a five-segment nonlinear resistor, a nonlinear saturable reactor, and a linear capacitor. Thus, by proper interpretation and identification of the parameters in the different circuits, the results of a detailed solution for one of the inverter circuits provide similar information and insight into the local and global behavior of each inverter in the family.

  3. Research on inverter test system of synchronous motor using modbus communication

    NASA Astrophysics Data System (ADS)

    Cao, Wenlun; Chen, Bei; He, Yuyao

    2013-03-01

    In this paper, the hardware architecture of the servo system composed by self-made inverter and permanent magnet synchronous motor is introduced as well as its measurement and control system software features. Basing on the Modbus-RTU protocols which contain the CRC data verification between IPC and the inverter, we have built a communication system. The measurement and control software of servo system are realized, which consists of self-made inverter and PMSM. Compared with the servo system which consists of Schindler's ATV31 inverter and SIMO's asynchronous motor, the results are given. The experiment parameters include harmonic content which is contained by phase current and voltage, and also the motor speed. The results show that the measurement and control system are stable and reliable. Both the harmonic content of the Inverter output and the motor speed meet the requirements.

  4. A current-source inverter fed induction motor drive system with reduced losses

    SciTech Connect

    Espinoza, J.R.; Joos, G.

    1995-12-31

    Standard low and medium induction power motor drives are based on the PWM voltage source inverter (VSI) fed from a diode rectifier. The dual topology, based on the current source inverter/rectifier structure is used in medium and high power applications. This paper addresses some of the drawbacks of this approach compared to the voltage source approach. The proposed drive features: (a) an on-line operated PWM inverter, using instantaneous output capacitor voltage control based on space vector modulation; (b) a line-synchronized PWM rectifier, with dc bus current control; (c) an additional inverter modulation index control loop, ensuring a constant inverter modulation index. The resulting advantages include: (a) ruggedness and inherent continuous regeneration capability; (b) near unity global input power factor; (c) reduced motor voltage distortion; (d) reduced dc bus inductor and switch conduction losses; (e) fast motor dynamic response; (f) elimination of motor circuit resonances. Simulated and experimental results based on a DSP implementation are given.

  5. Intracranial extension of Schneiderian inverted papilloma: a case report and literature review

    PubMed Central

    Pitak-Arnnop, Poramate; Bertolini, Julia; Dhanuthai, Kittipong; Hendricks, Jörg; Hemprich, Alexander; Pausch, Niels Christian

    2012-01-01

    Inverted papilloma is an uncommon primary nasal tumor. Despite its benign nature, this tumor represents three typical characteristics: a high propensity of recurrence, local aggressiveness and association with malignancy. Inverted papilloma can reduce the patient’s quality of life due to compromised nasal function, extension to the orbit and brain. The authors reported the unusual case of a 72-year-old male patient with inverted papilloma, which fatally extended to the intracranial temporal fossa after multiple recurrences. To the authors’ knowledge, this is the twelfth case in the literature of inverted papilla extending into the temporal fossa. The current and pertinent literature in English, French and German was reviewed, and an algorithm for managing inverted papilloma was also proposed. PMID:22737105

  6. Evaluation of Multiple Inverter Volt-VAR Control Interactions with Realistic Grid Impedances

    SciTech Connect

    Chakraborty, Sudipta; Hoke, Anderson; Lundstrom, Blake

    2015-07-03

    Integration of large numbers of distributed photovoltaic (PV) systems in electric distribution circuits often requires advanced functions (e.g. volt-VAR, frequency-Watt etc.). However, significant concerns have been raised about potential for PV inverters with such controls to interact with one another in a way that could cause grid instability. The lack of standardized inverter models makes it hard to simulate such transient interactions in software. Similarly it is very hard to test these dynamic inverter interactions in the laboratory. In this paper, unique Power Hardware-in-the-Loop (PHIL) techniques are presented to experimentally test for interactions of multiple PV inverters connected to multiple points-of-common-coupling (PCCs) with grid impedances between them. Sample test results are provided from simulation-only scenarios and PHIL testing. Though simulation results indicated possible harmful interactions between inverters' volt-VAR controllers; no such interactions were found in the limited hardware testing.

  7. Improvement on an inverted decoupling technique for a class of stable linear multivariable processes.

    PubMed

    Chen, Peiying; Zhang, Weidong

    2007-04-01

    This paper improves an inverted decoupling technique for a class of stable linear multivariable processes with multiple time delays and nonminimum-phase zeros. Two decoupling schemes are proposed based on the inverted decoupling technique. One is a developed inverted decoupling scheme. In this scheme, the decoupler is designed such that the inverted decoupling technique accommodates a wider field than the one introduced in the published literature. However, due to the stability issue, some multivariable processes still cannot be decoupled by the inverted decoupling structure. To solve this problem, another modified decoupling scheme with unity feedback structure is suggested for implementation. The Internal Model Control (IMC) theory is applied here to design PI/PID controllers for the decoupled processes. Furthermore, in the presence of multiplicative input uncertainty, low bounds of the control parameters are derived quantitatively for guaranteeing robust stability of the system. Simulations are illustrated for demonstrating the validity of the proposed control schemes. PMID:17343860

  8. DNA Triplet Repeat Expansion and Mismatch Repair

    PubMed Central

    Iyer, Ravi R.; Pluciennik, Anna; Napierala, Marek; Wells, Robert D.

    2016-01-01

    DNA mismatch repair is a conserved antimutagenic pathway that maintains genomic stability through rectification of DNA replication errors and attenuation of chromosomal rearrangements. Paradoxically, mutagenic action of mismatch repair has been implicated as a cause of triplet repeat expansions that cause neurological diseases such as Huntington disease and myotonic dystrophy. This mutagenic process requires the mismatch recognition factor MutSβ and the MutLα (and/or possibly MutLγ) endonuclease, and is thought to be triggered by the transient formation of unusual DNA structures within the expanded triplet repeat element. This review summarizes the current knowledge of DNA mismatch repair involvement in triplet repeat expansion, which encompasses in vitro biochemical findings, cellular studies, and various in vivo transgenic animal model experiments. We present current mechanistic hypotheses regarding mismatch repair protein function in mediating triplet repeat expansions and discuss potential therapeutic approaches targeting the mismatch repair pathway. PMID:25580529

  9. Repeat radiosurgery for cerebral arteriovenous malformations.

    PubMed

    Awad, Ahmed J; Walcott, Brian P; Stapleton, Christopher J; Ding, Dale; Lee, Cheng-Chia; Loeffler, Jay S

    2015-06-01

    We perform a systematic review of repeat radiosurgery for cerebral arteriovenous malformations (AVM) with an emphasis on lesion obliteration rates and complications. Radiosurgery is an accepted treatment modality for AVM located in eloquent cortex or deep brain structures. For residual or persistent lesions, repeat radiosurgery can be considered if sufficient time has passed to allow for a full appreciation of treatment effects, usually at least 3years. A systematic review was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. References for this review were identified by searches of MEDLINE, Web of Science and Google Scholar databases. A total of 14 studies comprising 733 patients met the review criteria and were included. For series that reported target dose at both first and repeat treatments, the weighted means were 19.42Gy and 19.06Gy, respectively. The mean and median obliteration rate for the repeat radiosurgery treatments were 61% (95% confidence interval 51.9-71.7%) and 61.5%, respectively. The median follow up following radiosurgery ranged from 19.5 to 80months. Time to complete obliteration after the repeat treatment ranged from 21 to 40.8months. The most common complications of repeat radiosurgery for AVM included hemorrhage (7.6%) and radiation-induced changes (7.4%). Repeat radiosurgery can be used to treat incompletely obliterated AVM with an obliteration rate of 61%. Complications are related to treatment effect latency (hemorrhage risk) as well as radiation-induced changes. Repeat radiosurgery can be performed at 3 years following the initial treatment, allowing for full realization of effects from the initial treatment prior to commencing therapy. PMID:25913746

  10. Digital repeat analysis; setup and operation.

    PubMed

    Nol, J; Isouard, G; Mirecki, J

    2006-06-01

    Since the emergence of digital imaging, there have been questions about the necessity of continuing reject analysis programs in imaging departments to evaluate performance and quality. As a marketing strategy, most suppliers of digital technology focus on the supremacy of the technology and its ability to reduce the number of repeats, resulting in less radiation doses given to patients and increased productivity in the department. On the other hand, quality assurance radiographers and radiologists believe that repeats are mainly related to positioning skills, and repeat analysis is the main tool to plan training needs to up-skill radiographers. A comparative study between conventional and digital imaging was undertaken to compare outcomes and evaluate the need for reject analysis. However, digital technology still being at its early development stages, setting a credible reject analysis program became the major task of the study. It took the department, with the help of the suppliers of the computed radiography reader and the picture archiving and communication system, over 2 years of software enhancement to build a reliable digital repeat analysis system. The results were supportive of both philosophies; the number of repeats as a result of exposure factors was reduced dramatically; however, the percentage of repeats as a result of positioning skills was slightly on the increase for the simple reason that some rejects in the conventional system qualifying for both exposure and positioning errors were classified as exposure error. The ability of digitally adjusting dark or light images reclassified some of those images as positioning errors. PMID:16421768

  11. Assumption or Fact? Line-to-Neutral Voltage Expression in an Unbalanced 3-Phase Circuit during Inverter Switching

    ERIC Educational Resources Information Center

    Masrur, M. A.

    2009-01-01

    This paper discusses the situation in a 3-phase motor or any other 3-phase system operating under unbalanced operating conditions caused by an open fault in an inverter switch. A dc voltage source is assumed as the input to the inverter, and under faulty conditions of the inverter switch, the actual voltage applied between the line to neutral…

  12. Stalled DNA Replication Forks at the Endogenous GAA Repeats Drive Repeat Expansion in Friedreich's Ataxia Cells.

    PubMed

    Gerhardt, Jeannine; Bhalla, Angela D; Butler, Jill Sergesketter; Puckett, James W; Dervan, Peter B; Rosenwaks, Zev; Napierala, Marek

    2016-08-01

    Friedreich's ataxia (FRDA) is caused by the expansion of GAA repeats located in the Frataxin (FXN) gene. The GAA repeats continue to expand in FRDA patients, aggravating symptoms and contributing to disease progression. The mechanism leading to repeat expansion and decreased FXN transcription remains unclear. Using single-molecule analysis of replicated DNA, we detected that expanded GAA repeats present a substantial obstacle for the replication machinery at the FXN locus in FRDA cells. Furthermore, aberrant origin activation and lack of a proper stress response to rescue the stalled forks in FRDA cells cause an increase in 3'-5' progressing forks, which could enhance repeat expansion and hinder FXN transcription by head-on collision with RNA polymerases. Treatment of FRDA cells with GAA-specific polyamides rescues DNA replication fork stalling and alleviates expansion of the GAA repeats, implicating DNA triplexes as a replication impediment and suggesting that fork stalling might be a therapeutic target for FRDA. PMID:27425605

  13. Automated genotyping of dinucleotide repeat markers

    SciTech Connect

    Perlin, M.W.; Hoffman, E.P. |

    1994-09-01

    The dinucleotide repeats (i.e., microsatellites) such as CA-repeats are a highly polymorphic, highly abundant class of PCR-amplifiable markers that have greatly streamlined genetic mapping experimentation. It is expected that over 30,000 such markers (including tri- and tetranucleotide repeats) will be characterized for routine use in the next few years. Since only size determination, and not sequencing, is required to determine alleles, in principle, dinucleotide repeat genotyping is easily performed on electrophoretic gels, and can be automated using DNA sequencers. Unfortunately, PCR stuttering with these markers generates not one band for each allele, but a pattern of bands. Since closely spaced alleles must be disambiguated by human scoring, this poses a key obstacle to full automation. We have developed methods that overcome this obstacle. Our model is that the observed data is generated by arithmetic superposition (i.e., convolution) of multiple allele patterns. By quantitatively measuring the size of each component band, and exploiting the unique stutter pattern associated with each marker, closely spaced alleles can be deconvolved; this unambiguously reconstructs the {open_quotes}true{close_quotes} allele bands, with stutter artifact removed. We used this approach in a system for automated diagnosis of (X-linked) Duchenne muscular dystrophy; four multiplexed CA-repeats within the dystrophin gene were assayed on a DNA sequencer. Our method accurately detected small variations in gel migration that shifted the allele size estimate. In 167 nonmutated alleles, 89% (149/167) showed no size variation, 9% (15/167) showed 1 bp variation, and 2% (3/167) showed 2 bp variation. We are currently developing a library of dinucleotide repeat patterns; together with our deconvolution methods, this library will enable fully automated genotyping of dinucleotide repeats from sizing data.

  14. A Preliminary Cost Study of the Dual Mode Inverter Controller

    SciTech Connect

    McKeever, J.W.

    2005-01-28

    In 1998, the Power Electronics and Electric Machinery Research Center (PEEMRC) at the Oak Ridge National Laboratory (ORNL) started a program to investigate alternate field weakening schemes for permanent magnet (PM) motors. The adjective ''alternate'' was used because at that time, outside research emphasis was on motors with interior-mounted PMs (IPMs). The PEEMRC emphasis was placed on motors with surface-mounted PMs (SPMs) because of the relative ease of manufacturing SPM motors compared with the IPM motors. Today the PEEMRC is continuing research on SPMs while examining the IPMs that have been developed by industry. Out of this task--the goal of which was to find ways to drive PM motors that inherently have low inductance at high speeds where their back-emf exceeds the supply voltage--ORNL developed and demonstrated the dual mode inverter control (DMIC) [1,2] method of field weakening for SPM motors. The predecessor of DMIC is conventional phase advance (CPA), which was developed by UQM Technologies, Inc. [3]. Fig. 1 shows the three sets of anti-parallel thyristors in the dashed box that comprise the DMIC. If one removes the dashed box by shorting each set of anti-parallel thyristors, the configuration becomes a conventional full bridge inverter on the left driving a three phase motor on the right. CPA may be used to drive this configuration ORNL's initial analyses of CPA and DMIC were based on driving motors with trapezoidal back-emfs [4-6], obtained using double layer lapped stator windings with one slot per pole per phase. A PM motor with a sinusoidal back-emf obtained with two poles per slot per phase has been analyzed under DMIC operation as a University of Tennessee-Knoxville (UTK) doctoral dissertation [7]. In the process of this research, ORNL has completed an analysis that explains and quantifies the role of inductance in these methods of control. The Appendix includes information on the equations for the three components of phase inductance, L{sub gap

  15. A SiC MOSFET Based Inverter for Wireless Power Transfer Applications

    SciTech Connect

    Onar, Omer C; Chinthavali, Madhu Sudhan; Campbell, Steven L; Ning, Puqi; White, Cliff P; Miller , John M.

    2014-01-01

    In a wireless power transfer (WPT) system, efficiency of the power conversion stages is crucial so that the WPT technology can compete with the conventional conductive charging systems. Since there are 5 or 6 power conversion stages, each stage needs to be as efficient as possible. SiC inverters are crucial in this case; they can handle high frequency operation and they can operate at relatively higher temperatures resulting in reduces cost and size for the cooling components. This study presents the detailed power module design, development, and fabrication of a SiC inverter. The proposed inverter has been tested at three center frequencies that are considered for the WPT standardization. Performance of the inverter at the same target power transfer level is analyzed along with the other system components. In addition, another SiC inverter has been built in authors laboratory by using the ORNL designed and developed SiC modules. It is shown that the inverter with ORNL packaged SiC modules performs simular to that of the inverter having commercially available SiC modules.

  16. Complete chloroplast genome of Trachelium caeruleum: extensiverearrangements are associated with repeats and tRNAs

    SciTech Connect

    Haberle, Rosemarie C.; Fourcade, Matthew L.; Boore, Jeffrey L.; Jansen, Robert K.

    2006-01-09

    Chloroplast genome structure, gene order and content arehighly conserved in land plants. We sequenced the complete chloroplastgenome sequence of Trachelium caeruleum (Campanulaceae) a member of anangiosperm family known for highly rearranged chloroplast genomes. Thetotal genome size is 162,321 bp with an IR of 27,273 bp, LSC of 100,113bp and SSC of 7,661 bp. The genome encodes 115 unique genes, with 19duplicated in the IR, a tRNA (trnI-CAU) duplicated once in the LSC and aprotein coding gene (psbJ) duplicated twice, for a total of 137 genes.Four genes (ycf15, rpl23, infA and accD) are truncated and likelynonfunctional; three others (clpP, ycf1 and ycf2) are so highly divergedthat they may now be pseudogenes. The most conspicuous feature of theTrachelium genome is the presence of eighteen internally unrearrangedblocks of genes that have been inverted or relocated within the genome,relative to the typical gene order of most angiosperm chloroplastgenomes. Recombination between repeats or tRNAs has been suggested as twomeans of chloroplast genome rearrangements. We compared the relativenumber of repeats in Trachelium to eight other angiosperm chloroplastgenomes, and evaluated the location of repeats and tRNAs in relation torearrangements. Trachelium has the highest number and largest repeats,which are concentrated near inversion endpoints or other rearrangements.tRNAs occur at many but not all inversion endpoints. There is likely nosingle mechanism responsible for the remarkable number of alterations inthis genome, but both repeats and tRNAs are clearly associated with theserearrangements. Land plant chloroplast genomes are highly conserved instructure, gene order and content. The chloroplast genomes of ferns, thegymnosperm Ginkgo, and most angiosperms are nearly collinear, reflectingthe gene order in lineages that diverged from lycopsids and the ancestralchloroplast gene order over 350 million years ago (Raubeson and Jansen,1992). Although earlier mapping studies

  17. Comparison of Vertical and Inverted-T Mammaplasties Using Photographic Measurements

    PubMed Central

    2013-01-01

    Background: Surgeons have long debated the relative merits of vertical and inverted-T mammaplasties. These debates have centered on surgeons’ opinions. Without measurements, this controversy is unlikely to be resolved. This study compares these common techniques using a recently published measurement system. Such a study using measurements on photographs matched for size and orientation has not been previously published. Methods: A prospective group of women undergoing primary vertical mastopexies, augmentation/mastopexies, and reductions (n = 78) was compared with a retrospective group of women treated with inverted-T mastopexies, augmentation/mastopexies, and reductions (n = 35). Consecutive patients with photographs at least 3 months after surgery and no subsequent procedures were evaluated. Results: All patient groups demonstrated a significant elevation (P < 0.001) of the breast mound. Vertical mastopexy, but not inverted-T mastopexy, increased breast projection and upper pole projection (P < 0.008). Neither vertical nor inverted-T breast reduction significantly increased breast projection. Vertical breast reduction better preserved breast projection (P < 0.017) than the inverted-T technique. Vertical reduction significantly increased upper pole projection (P < 0.008), but inverted-T reduction did not. The inverted-T breast reduction caused greater breast constriction (reduced lower pole distance) than the vertical technique. Lower pole ratios were significantly higher for inverted-T patients (P < 0.01), indicating boxier lower poles. Conclusions: Photographic measurements of relevant breast parameters favor the vertical technique over the inverted-T technique and are consistent with anatomical considerations and clinical experience. PMID:25289283

  18. Variable efficacy of repeated annual influenza vaccination.

    PubMed

    Smith, D J; Forrest, S; Ackley, D H; Perelson, A S

    1999-11-23

    Conclusions have differed in studies that have compared vaccine efficacy in groups receiving influenza vaccine for the first time to efficacy in groups vaccinated more than once. For example, the Hoskins study [Hoskins, T. W., Davis, J. R., Smith, A. J., Miller, C. L. & Allchin, A. (1979) Lancet i, 33-35] concluded that repeat vaccination was not protective in the long term, whereas the Keitel study [Keitel, W. A., Cate, T. R., Couch, R. B., Huggins, L. L. & Hess, K. R. (1997) Vaccine 15, 1114-1122] concluded that repeat vaccination provided continual protection. We propose an explanation, the antigenic distance hypothesis, and test it by analyzing seven influenza outbreaks that occurred during the Hoskins and Keitel studies. The hypothesis is that variation in repeat vaccine efficacy is due to differences in antigenic distances among vaccine strains and between the vaccine strains and the epidemic strain in each outbreak. To test the hypothesis, antigenic distances were calculated from historical hemagglutination inhibition assay tables, and a computer model of the immune response was used to predict the vaccine efficacy of individuals given different vaccinations. The model accurately predicted the observed vaccine efficacies in repeat vaccinees relative to the efficacy in first-time vaccinees (correlation 0.87). Thus, the antigenic distance hypothesis offers a parsimonious explanation of the differences between and within the Hoskins and Keitel studies. These results have implications for the selection of influenza vaccine strains, and also for vaccination strategies for other antigenically variable pathogens that might require repeated vaccination. PMID:10570188

  19. Quantum key distribution over probabilistic quantum repeaters

    NASA Astrophysics Data System (ADS)

    Amirloo, Jeyran; Razavi, Mohsen; Majedi, A. Hamed

    2010-09-01

    A feasible route toward implementing long-distance quantum key distribution (QKD) systems relies on probabilistic schemes for entanglement distribution and swapping as proposed in the work of Duan, Lukin, Cirac, and Zoller (DLCZ) [Nature (London)NATUAS0028-083610.1038/35106500 414, 413 (2001)]. Here, we calculate the conditional throughput and fidelity of entanglement for DLCZ quantum repeaters by accounting for the DLCZ self-purification property in the presence of multiple excitations in the ensemble memories as well as loss and other sources of inefficiency in the channel and measurement modules. We then use our results to find the generation rate of secure key bits for QKD systems that rely on DLCZ quantum repeaters. We compare the key generation rate per logical memory employed in the two cases with and without a repeater node. We find the crossover distance beyond which the repeater system outperforms the nonrepeater one. That provides us with the optimum internode distancing in quantum repeater systems. We also find the optimal excitation probability at which the QKD rate peaks. Such an optimum probability, in most regimes of interest, is insensitive to the total distance.

  20. Polarization-encoded all-optical quaternary universal inverter and design of multivalued flip-flop

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, Tanay; Roy, Jitendra Nath

    2010-03-01

    Quaternary inverters are the fundamental building blocks of multivalued flip-flops (MVFFs). A novel all-optical quaternary universal inverter circuit with the help of a semiconductor optical amplifier-assisted Sagnac switch is proposed and described. This circuit exploits the polarization properties of light. Different logical states are represented by different polarization states of light. A terahertz optical asymmetric multiplexer-based gate plays an important role here. Numerical simulation results confirming the described method are given. An all-optical circuit for a MVFF (quaternary) with the help of our proposed quaternary universal inverter is also designed, and simulation results are presented.

  1. A new inverter topology using GTO commutation. [Gate Turn Off thyristor

    NASA Technical Reports Server (NTRS)

    Rippel, W. E.

    1983-01-01

    A new N-phase, forced commutated bridge inverter topology has been developed wherein a single Gate Turn Off Thyristor (GTO) is used to commutate each of 2N main Thyristors (SCRs). Since, for most applications, the primary loss mechanism is the SCR forward drop, very high efficiencies are possible. Compared with conventional pure SCR and pure GTO inverters, cost per kW is lower - in the former case due to the large cost differential between GTOs and SCRs. Other advantages of the new inverter include high power density, low switching losses and stresses, modulation flexibility and amenability to high voltage and high frequency operation.

  2. Advances in series resonant inverter technology and its effect on spacecraft employing electric propulsion

    NASA Technical Reports Server (NTRS)

    Robson, R. R.

    1982-01-01

    The efficiency of transistorized Series Resonant Inverters (SRIs), which is higher than that of silicon-controlled rectifier alternatives, reduces spacecraft radiator requirements by 40% and may eliminate the need for heat pipes on 30-cm ion thruster systems. Recently developed 10- and 25-kW inverters have potential applications in gas thrusters, and represent the first spaceborne SRI designs for such power levels. Attention is given to the design and control system approaches employed in these inverter designs to improve efficiency and reduce weight, along with the impact of such improved parameters on electric propulsion systems.

  3. Silicon-controlled-rectifier square-wave inverter with protection against commutation failure

    NASA Technical Reports Server (NTRS)

    Birchenough, A. G.

    1971-01-01

    The square-wave SCR inverter that was designed, built, and tested includes a circuit to turn off the inverter in case of commutation failure. The basic power stage is a complementary impulse-commutated parallel inverter consisting of only six components. The 400-watt breadboard was tested while operating at + or - 28 volts, and it had a peak efficiency of 95.5 percent at 60 hertz and 91.7 percent at 400 hertz. The voltage regulation for a fixed input was 3 percent at 60 hertz. An analysis of the operation and design information is included.

  4. Static and flyover noise measurements of an inverted profile exhaust jet

    NASA Technical Reports Server (NTRS)

    Burcham, F. W., Jr.; Lasagna, P. L.; Kurtenbach, F. J.

    1977-01-01

    Tests using a TF30 mixed flow afterburning turbofan engine in an F-111 airplane were conducted to study the noise characteristics of an inverted velocity profile jet. Full-authority digital engine control allowed the inverted profile jet to be compared to a uniform jet of equal thrust statically and in flight. An exhaust velocity survey showed that the ratio of the outer to inner stream velocities was 1.37; therefore, only small noise reductions were expected. At static conditions, the inverted profile jet was approximately 3 decibels quieter than the uniform jet at peak noise angles. During a flyover it was approximately 1 decibel quieter.

  5. High fill factor and thermal stability of bilayer organic photovoltaic cells with an inverted structure

    NASA Astrophysics Data System (ADS)

    Wang, Zhongqiang; Hong, Ziruo; Zhuang, Taojun; Chen, Guo; Sasabe, Hisahiro; Yokoyama, Daisuke; Kido, Junji

    2015-02-01

    In this study, we fabricated planar heterojunction photovoltaic cells with inverted device structures based on tetraphenyldibenzoperiflanthene and fullerene-70 (C70). With proper designs of device architecture and selection of electrode buffers, a high fill factor and power conversion efficiency were obtained due to large shunt resistance (Rsh) and efficient carrier collection. Optical simulation reveals that field-dependent recombination is depressed in the inverted structure cells because of less light absorption in short wavelength range, resulting in high fill factor. More importantly, high thermal stability of inverted structure cells was demonstrated via utilizing stable electrode buffers.

  6. Four new cases of inverted terminal duplication: A modified hypothesis of mechanism of origin

    SciTech Connect

    Hoo, J.J.; Chao, M.; Szego, K.

    1995-09-25

    We present 4 recently diagnosed cases of inverted tandem duplication with involvement of the respective terminal band. Based on these 4 cases and review of the literature, the term {open_quotes}inverted terminal duplication{close_quotes} is proposed to designate specifically the type of inverted tandem duplication which involves the terminal band. A modification of the previous hypothesis of mechanism of origin is advanced. It is speculated further that a telomeric deletion of a meiotic chromosome followed by a U-type reunion of the chromatids, considered to be the first steps of the proposed mechanism of origin, may not be a rare gonadal event. 12 refs., 5 figs.

  7. Intra-abdominal inverted umblical cord in gastroschisis: a unique ultrasound finding.

    PubMed

    Koc, Gonca; Courtier, Jesse L; Kim, Jane S; Miniati, Douglas N; MacKenzie, John D

    2014-01-01

    A relatively new surgical technique allows for sutureless closure of a gastroschisis defect. Immediately after birth, a long umbilical cord stump is temporarily inverted into the abdominal cavity and later retracted and used to close the abdominal wall defect. Knowledge of this entity is important since the inverted umbilical cord simulates an intra-abdominal mass on cross-sectional imaging. While this procedure is well described in the surgical literature, the imaging features of inverted umbilical cord have yet to be reported. The case presented here highlights the sonographic imaging findings of the umbilical cord during the intestinal decompression phase of sutureless repair of gastroschisis. PMID:23907187

  8. Radiation dependence of inverter propagation delay from timing sampler measurements

    NASA Technical Reports Server (NTRS)

    Buehler, M. G.; Blaes, B. R.; Lin, Y.-S.

    1989-01-01

    A timing sampler consisting of 14 four-stage inverter-pair chains with different load capacitances was fabricated in 1.6-micron n-well CMOS and irradiated with cobalt-60 at 10 rad(Si)/s. For this CMOS process the measured results indicate that the rising delay increases by about 2.2 ns/Mrad(Si) and the falling delay increase is very small, i.e., less than 300 ps/Mrad(Si). The amount of radiation-induced delay depends on the size of the load capacitance. The maximum value observed for this effect was 5.65 ns/pF-Mrad(Si). Using a sensitivity analysis, the sensitivity of the rising delay to radiation can be explained by a simple timing model and the radiation sensitivity of dc MOSFET parameters. This same approach could not explain the insensitivity of the falling delay to radiation. This may be due to a failure of the timing model and/or trapping effects.

  9. Efficiency optimal control for AC drives with PWM inverters

    SciTech Connect

    Zach, F.C.; Ertl, H.

    1985-07-01

    For electrical drives using pulsewidth modulation (PWM) inverters and ac motors, methods for efficiency optimal control (EOC) have been developed. They are based on the most complete motor models, including such features as rotor skin effect. Furthermore, new solutions for selected harmonic elimination (SHE) are given. These new solutions come close to EOC. Also, it has been found that EOC solutions (although basically load-dependent as opposed to SHE) do not vary much with the motor used or the motor model applied. Even using a simple R-L series circuit as motor model does not change the solutions much. It is found that using the solutions gained from such a simple model is not more than two points off the real optimum based on a very complete motor model. (For this definition, the absolute harmonic loss minimum is given as zero points, the overall maximum as 100 points with a linear scale in between.) Therefore, one can use one EOC solution for all motors with sufficient accuracy, or, as second best solution, the new form of SHE. Therefore, the EOC solution can be judged load-independent. The implementation by microprocessor-based systems is as easy for other PWM methods. EOC for three and five switching angles per quarter period is discussed, as well as the new solutions for SHE for up to nine angles.

  10. Magnetic materials selection for static inverter and converter transformers

    NASA Technical Reports Server (NTRS)

    Mclyman, W. T.

    1973-01-01

    A program to study magnetic materials is described for use in spacecraft transformers used in static inverters, converters, and transformer-rectifier supplies. Different magnetic alloys best suited for high-frequency and high-efficiency applications were comparatively investigated together with an investigation of each alloy's inherent characteristics. The materials evaluated were the magnetic alloys: (1) 50% Ni, 50% Fe; (2) 79% Ni, 17% Fe, 4% Mo; (3) 48% Ni, 52% Fe; (4) 78% Ni, 17% Fe, 5% Mo; and (5) 3% Si, 97% Fe. Investigations led to the design of a transformer with a very low residual flux. Tests were performed to determine the dc and ac magnetic properties at 2400 Hz using square-wave excitation. These tests were performed on uncut cores, which were then cut for comparison of the gapped and ungapped magnetic properties. When the data of many transformers in many configurations were compiled the optimum transformer was found to be that with the lowest residual flux and a small amount of air gap in the magnetic material. The data obtained from these tests are described, and the potential uses for the materials are discussed.

  11. Math expression retrieval using an inverted index over symbol pairs

    NASA Astrophysics Data System (ADS)

    Stalnaker, David; Zanibbi, Richard

    2015-01-01

    We introduce a new method for indexing and retrieving mathematical expressions, and a new protocol for evaluating math formula retrieval systems. The Tangent search engine uses an inverted index over pairs of symbols in math expressions. Each key in the index is a pair of symbols along with their relative distance and vertical displacement within an expression. Matched expressions are ranked by the harmonic mean of the percentage of symbol pairs matched in the query, and the percentage of symbol pairs matched in the candidate expression. We have found that our method is fast enough for use in real time and finds partial matches well, such as when subexpressions are re-arranged (e.g. expressions moved from the left to the right of an equals sign) or when individual symbols (e.g. variables) differ from a query expression. In an experiment using expressions from English Wikipedia, student and faculty participants (N=20) found expressions returned by Tangent significantly more similar than those from a text-based retrieval system (Lucene) adapted for mathematical expressions. Participants provided similarity ratings using a 5-point Likert scale, evaluating expressions from both algorithms one-at-a-time in a randomized order to avoid bias from the position of hits in search result lists. For the Lucene-based system, precision for the top 1 and 10 hits averaged 60% and 39% across queries respectively, while for Tangent mean precision at 1 and 10 were 99% and 60%. A demonstration and source code are publicly available.

  12. Inverted Outflow Ground Testing of Cryogenic Propellant Liquid Acquisition Devices

    NASA Technical Reports Server (NTRS)

    Chato, David J.; Hartwig, Jason W.; Rame, Enrique; McQuillen, John B.

    2014-01-01

    NASA is currently developing propulsion system concepts for human exploration. These propulsion concepts will require the vapor free acquisition and delivery of the cryogenic propellants stored in the propulsion tanks during periods of microgravity to the exploration vehicles engines. Propellant management devices (PMD's), such as screen channel capillary liquid acquisition devices (LAD's), vanes and sponges have been used for earth storable propellants in the Space Shuttle Orbiter and other spacecraft propulsion systems, but only very limited propellant management capability currently exists for cryogenic propellants. NASA is developing PMD technology as a part of their cryogenic fluid management (CFM) project. System concept studies have looked at the key factors that dictate the size and shape of PMD devices and established screen channel LADs as an important component of PMD design. Modeling validated by normal gravity experiments is examining the behavior of the flow in the LAD channel assemblies (as opposed to only prior testing of screen samples) at the flow rates representative of actual engine service (similar in size to current launch vehicle upper stage engines). Recently testing of rectangular LAD channels has included inverted outflow in liquid oxygen and liquid hydrogen. This paper will report the results of liquid oxygen testing compare and contrast them with the recently published hydrogen results; and identify the sensitivity of these results to flow rate and tank internal pressure.

  13. Inverted Outflow Ground Testing of Cryogenic Propellant Liquid Acquisition Devices

    NASA Technical Reports Server (NTRS)

    Chato, David J.; Hartwig, Jason W.; Rame, Enrique; McQuillen, John B.

    2014-01-01

    NASA is currently developing propulsion system concepts for human exploration. These propulsion concepts will require the vapor free acquisition and delivery of the cryogenic propellants stored in the propulsion tanks during periods of microgravity to the exploration vehicles engines. Propellant management devices (PMDs), such as screen channel capillary liquid acquisition devices (LADs), vanes and sponges have been used for earth storable propellants in the Space Shuttle Orbiter and other spacecraft propulsion systems, but only very limited propellant management capability currently exists for cryogenic propellants. NASA is developing PMD technology as a part of their cryogenic fluid management (CFM) project. System concept studies have looked at the key factors that dictate the size and shape of PMD devices and established screen channel LADs as an important component of PMD design. Modeling validated by normal gravity experiments is examining the behavior of the flow in the LAD channel assemblies (as opposed to only prior testing of screen samples) at the flow rates representative of actual engine service (similar in size to current launch vehicle upper stage engines). Recently testing of rectangular LAD channels has included inverted outflow in liquid oxygen and liquid hydrogen. This paper will report the results of liquid oxygen testing compare and contrast them with the recently published hydrogen results; and identify the sensitivity these results to flow rate and tank internal pressure.

  14. Quantum Spin Hall Effect in Inverted Type II Semiconductors

    SciTech Connect

    Liu, Chaoxing; Hughes, Taylor L.; Qi, Xiao-Liang; Wang, Kang; Zhang, Shou-Cheng; /Stanford U., Phys. Dept.

    2010-03-19

    The quantum spin Hall (QSH) state is a topologically non-trivial state of quantum matter which preserves time-reversal symmetry; it has an energy gap in the bulk, but topologically robust gapless states at the edge. Recently, this novel effect has been predicted and observed in HgTe quantum wells. In this work we predict a similar effect arising in Type-II semiconductor quantum wells made from InAs/GaSb/AlSb. Because of a rare band alignment the quantum well band structure exhibits an 'inverted' phase similar to CdTe/HgTe quantum wells, which is a QSH state when the Fermi level lies inside the gap. Due to the asymmetric structure of this quantum well, the effects of inversion symmetry breaking and inter-layer charge transfer are essential. By standard self-consistent calculations, we show that the QSH state persists when these corrections are included, and a quantum phase transition between the normal insulator and the QSH phase can be electrically tuned by the gate voltage.

  15. Inverted papillomas and benign nonneoplastic lesions of the nasal cavity

    PubMed Central

    Casiano, Roy R.

    2012-01-01

    Background: Benign lesions of the nasal cavity represent a diverse group of pathologies. Furthermore, each of these disorders may present differently in any given patient as pain and discomfort, epistaxis, headaches, vision changes, or nasal obstruction. Although these nasal masses are benign, many of them have a significant capacity for local tissue destruction and symptomatology secondary to this destruction. Advances in office-based endoscopic nasendoscopy have equipped the otolaryngologist with a safe, inexpensive, and rapid means of directly visualizing lesions within the nasal cavity and the initiation of appropriate treatment. Methods: The purpose of this study is to review the diagnosis, management, and controversies of many of the most common benign lesions of the nasal cavity encountered by the primary care physician or otolaryngologist. Results: This includes discussion of inverted papilloma (IP), juvenile angiofibroma, squamous papilloma, pyogenic granuloma, hereditary hemorrhagic telangiectasia, schwannoma, benign fibro-osseous lesions, and other benign lesions of the nasal cavity, with particular emphasis on IP and juvenile angiofibroma. Conclusion: A diverse array of benign lesions occur within the nasal cavity and paranasal cavities. Despite their inability to metastasize, many of these lesions have significant capability for local tissue destruction and recurrence. PMID:22487294

  16. Substrate and electrode potential affect electrotrophic activity of inverted bioanodes.

    PubMed

    Hartline, Rosanna M; Call, Douglas F

    2016-08-01

    Electricity-consuming microbial communities can serve as biocathodic catalysts in microbial electrochemical technologies. Initiating their functionality, however, remains a challenge. One promising approach is the polarity inversion of bioanodes. The objective of this study was to examine the impact of bioanode substrate and electrode potentials on inverted electrotrophic activity. Bioanodes derived from domestic wastewater were operated at -0.15V or +0.15V (vs. standard hydrogen electrode) with either acetate or formate as the sole carbon source. After this enrichment phase, cathodic linear sweep voltammetry and polarization revealed that formate-enriched cultures consumed almost 20 times the current (-3.0±0.78mA; -100±26A/m(3)) than those established with acetate (-0.16±0.09mA; -5.2±2.9A/m(3)). The enrichment electrode potential had an appreciable impact for formate, but not acetate, adapted cultures, with the +0.15V enrichment generating twice the cathodic current of the -0.15V enrichment. The total charge consumed during cathodic polarization was comparable to the charge released during subsequent anodic polarization for the formate-adapted cultures, suggesting that these communities accumulated charge or generated reduced products that could be rapidly oxidized. These findings imply that it may be possible to optimize electrotrophic activity through specific bioanodic enrichment procedures. PMID:26946157

  17. InVERT molding for scalable control of tissue microarchitecture

    PubMed Central

    Stevens, KR; Ungrin, MD; Schwartz, RE; Ng, S; Carvalho, B; Christine, KS; Chaturvedi, RR; Li, CY; Zandstra, PW; Chen, CS; Bhatia, SN

    2013-01-01

    Complex tissues contain multiple cell types that are hierarchically organized within morphologically and functionally distinct compartments. Construction of engineered tissues with optimized tissue architecture has been limited by tissue fabrication techniques, which do not enable versatile microscale organization of multiple cell types in tissues of size adequate for physiologic studies and tissue therapies. Here we present an ‘Intaglio-Void/Embed-Relief Topographic (InVERT) molding’ method for microscale organization of many cell types, including induced pluripotent stem cell (iPS)-derived progeny, within a variety of synthetic and natural extracellular matrices and across tissues of sizes appropriate for in vitro, pre-clinical, and clinical studies. We demonstrate that compartmental placement of non-parenchymal cells relative to primary or iPS-derived hepatocytes, compartment microstructure, and cellular composition modulate hepatic functions. Configurations found to sustain physiologic function in vitro also result in survival and function in mice for at least four weeks, demonstrating the importance of architectural optimization prior to implantation. PMID:23673632

  18. Interfacial thermal degradation in inverted organic solar cells

    SciTech Connect

    Greenbank, William; Hirsch, Lionel; Wantz, Guillaume; Chambon, Sylvain

    2015-12-28

    The efficiency of organic photovoltaic (OPV) solar cells is constantly improving; however, the lifetime of the devices still requires significant improvement if the potential of OPV is to be realised. In this study, several series of inverted OPV were fabricated and thermally aged in the dark in an inert atmosphere. It was demonstrated that all of the devices undergo short circuit current-driven degradation, which is assigned to morphology changes in the active layer. In addition, a previously unreported, open circuit voltage-driven degradation mechanism was observed that is highly material specific and interfacial in origin. This mechanism was specifically observed in devices containing MoO{sub 3} and silver as hole transporting layers and electrode materials, respectively. Devices with this combination were among the worst performing devices with respect to thermal ageing. The physical origins of this mechanism were explored by Rutherford backscattering spectrometry and atomic force microscopy and an increase in roughness with thermal ageing was observed that may be partially responsible for the ageing mechanism.

  19. Development and Characterization of Inverted Helicon Plasma Sources

    NASA Astrophysics Data System (ADS)

    Masters, Benjamin; Ruzic, David

    2007-11-01

    Helicon plasmas are useful as hot, dense sources requiring low magnetic fields. Since Boswell's^1 use of helicon waves in low pressure gas, research has strived to determine the wave-plasma coupling mechanism. Trivelpiece-Gould (TG) modes^2 remain a strong candidate. An inverted helicon plasma source uses a Nagoya Type III dielectric-covered helicon antenna, placed within a vacuum chamber. The antenna is 8.2 cm long, 2.2 cm in radius, using an frequency of 13.56 MHz. Basic dispersion relation theory is developed as an extension of existing helicon theory which includes TG modes and annular helicons^3. With this arrangement, diagnostic measurements are made inside and outside the antenna volume. To characterize the plasma, an RF-compensated Langmuir probe measures ne and Te, and 3 B-dot probes measure the field shape of the R, Theta and Z components about the antenna region in the R and Z directions. Typical ne and Te in an Ar plasma were found to be 3x10^18/m^3 and 3 eV. The goal of this work is to find another configuration to determine the method of efficient plasma heating. [1] R.W. Boswell, Phys. Lett. 33A, 457 (1970) [2] A.W. Trivelpiece and R.W. Gould, Jour. App. Phys. 30 (11) (1959) [3] M. Yano and M.L.R. Walker, Phys. of Plasmas. 13 (063501) (2006)

  20. Characterization of an Inverted Geometry Helicon Plasma Source

    NASA Astrophysics Data System (ADS)

    Masters, Benjamin; Ruzic, David

    2006-10-01

    Helicon plasmas are useful as hot, dense sources requiring low magnetic fields. Since Boswell's^1 use of helicon waves in low pressure gas, no single theory fully explains the wave-plasma coupling mechanism. However, Trivelpiece-Gould modes^2 remain a strong candidate. An inverted geometry helicon plasma source is further explored, using a dielectric-covered helicon antenna, placed within a vacuum chamber, in contrast to conventional antennas that surround a dielectric cylinder. A Nagoya Type III antenna is used, other antennas are equally feasible. Many industrial advantages of such a system exist; namely, more efficient electromagnets, as well as producing a plasma with a larger radius than the antenna. With this arrangement, diagnostic measurements can be made arbitrarily close to the antenna. To characterize the plasma, an RF-compensated Langmuir probe measures electron temperature and density, while a B-dot probe measures the field shape inside and outside of the antenna region. In addition, optical emission spectroscopy observes changes in plasma intensity for mode jumps, and measures line ratios. 1. R.W. Boswell, Phys. Lett. 33A, 457 (1970) 2. A.W. Trivelpiece and R.W. Gould, Jour. App. Phys. 30 (11) (1959)