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Sample records for 14-bp inverted repeat

  1. Copy number of tandem direct repeats within the inverted repeats of Marek's disease virus DNA.

    PubMed

    Kanamori, A; Nakajima, K; Ikuta, K; Ueda, S; Kato, S; Hirai, K

    1986-12-01

    We previously reported that DNA of the oncogenic strain BC-1 of Marek's disease virus serotype 1 (MDV1) contains three units of tandem direct repeats with 132 base pair (bp) repeats within the inverted repeats of the long regions of the MDV1 genome, whereas the attenuated, nononcogenic viral DNA contains multiple units of tandem direct repeats (Maotani et al., 1986). In the present study, the difference in the copy numbers of 132 bp repeats of oncogenic and nononcogenic MDV1 DNAs in other strains of MDV1 was investigated by Southern blot hybridization. The main copy numbers in different oncogenic MDV1 strains differed: those of BC-1, JM and highly oncogenic Md5 were 3, 5 to 12 and 2, respectively. The viral DNA population with two units of repeats was small, but detectable, in cells infected with either the oncogenic BC-1 or JM strain. The MDV1 DNA in various MD cell lines contained either two units or both two and three units of repeats. The significance of the copy number of repeats in oncogenicity of MDV1 is discussed.

  2. Associations between inverted repeats and the structural evolution of bacterial genomes.

    PubMed Central

    Achaz, Guillaume; Coissac, Eric; Netter, Pierre; Rocha, Eduardo P C

    2003-01-01

    The stability of the structure of bacterial genomes is challenged by recombination events. Since major rearrangements (i.e., inversions) are thought to frequently operate by homologous recombination between inverted repeats, we analyzed the presence and distribution of such repeats in bacterial genomes and their relation to the conservation of chromosomal structure. First, we show that there is a strong under-representation of inverted repeats, relative to direct repeats, in most chromosomes, especially among the ones regarded as most stable. Second, we show that the avoidance of repeats is frequently associated with the stability of the genomes. Closely related genomes reported to differ in terms of stability are also found to differ in the number of inverted repeats. Third, when using replication strand bias as a proxy for genome stability, we find a significant negative correlation between this strand bias and the abundance of inverted repeats. Fourth, when measuring the recombining potential of inverted repeats and their eventual impact on different features of the chromosomal structure, we observe a tendency of repeats to be located in the chromosome in such a way that rearrangements produce a smaller strand switch and smaller asymmetries than expected by chance. Finally, we discuss the limitations of our analysis and the influence of factors such as the nature of repeats, e.g., transposases, or the differences in the recombination machinery among bacteria. These results shed light on the challenges imposed on the genome structure by the presence of inverted repeats. PMID:12930739

  3. Recombination-restarted replication makes inverted chromosome fusions at inverted repeats.

    PubMed

    Mizuno, Ken'Ichi; Miyabe, Izumi; Schalbetter, Stephanie A; Carr, Antony M; Murray, Johanne M

    2013-01-10

    Impediments to DNA replication are known to induce gross chromosomal rearrangements (GCRs) and copy-number variations (CNVs). GCRs and CNVs underlie human genomic disorders and are a feature of cancer. During cancer development, environmental factors and oncogene-driven proliferation promote replication stress. Resulting GCRs and CNVs are proposed to contribute to cancer development and therapy resistance. When stress arrests replication, the replisome remains associated with the fork DNA (stalled fork) and is protected by the inter-S-phase checkpoint. Stalled forks efficiently resume when the stress is relieved. However, if the polymerases dissociate from the fork (fork collapse) or the fork structure breaks (broken fork), replication restart can proceed either by homologous recombination or microhomology-primed re-initiation. Here we ascertain the consequences of replication with a fork restarted by homologous recombination in fission yeast. We identify a new mechanism of chromosomal rearrangement through the observation that recombination-restarted forks have a considerably high propensity to execute a U-turn at small inverted repeats (up to 1 in 40 replication events). We propose that the error-prone nature of restarted forks contributes to the generation of GCRs and gene amplification in cancer, and to non-recurrent CNVs in genomic disorders.

  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. FSM model correlation identification method based on invert-repeated m-sequence

    NASA Astrophysics Data System (ADS)

    Lei, Luo-lan; Wang, Qiang

    2014-09-01

    Fast steering mirror (FSM) is one of the most important components in electro-optical tracking system and access to FSM model is the basis for controlling and fault diagnosis. This paper presented a correlation identification method based on Invert-Repeated m-sequence which can be used in the electro-optical tracking system to achieve the model of FSM under low sampling rate. Firstly, this article discussed the properties of the Invert-Repeated m-sequence and program implemented in matlab language, then analyzed the principle of correlation identification method based on Invert-Repeated m-sequence by utilizing Wiener-Hopf equation which is simple to achieve with strong anti-jamming capability and small perturbations on the system. Finally, a FSM model with the experiment data got by Dynamic Signal Analyzer was built in Matlab/Simulink and identified by the method mentioned in the paper. The experiment showed that correlation identification method which has certain actual application value, based on Invert-Repeated m-sequence can obtain more accurate recognition results even if the FSM system's output signal contained large variance noise.

  6. 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...

  7. 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

  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.

  9. 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

  10. Palindrome analyser - A new web-based server for predicting and evaluating inverted repeats in nucleotide sequences.

    PubMed

    Brázda, Václav; Kolomazník, Jan; Lýsek, Jiří; Hároníková, Lucia; Coufal, Jan; Št'astný, Jiří

    2016-09-30

    DNA cruciform structures play an important role in the regulation of natural processes including gene replication and expression, as well as nucleosome structure and recombination. They have also been implicated in the evolution and development of diseases such as cancer and neurodegenerative disorders. Cruciform structures are formed by inverted repeats, and their stability is enhanced by DNA supercoiling and protein binding. They have received broad attention because of their important roles in biology. Computational approaches to study inverted repeats have allowed detailed analysis of genomes. However, currently there are no easily accessible and user-friendly tools that can analyse inverted repeats, especially among long nucleotide sequences. We have developed a web-based server, Palindrome analyser, which is a user-friendly application for analysing inverted repeats in various DNA (or RNA) sequences including genome sequences and oligonucleotides. It allows users to search and retrieve desired gene/nucleotide sequence entries from the NCBI databases, and provides data on length, sequence, locations and energy required for cruciform formation. Palindrome analyser also features an interactive graphical data representation of the distribution of the inverted repeats, with options for sorting according to the length of inverted repeat, length of loop, and number of mismatches. Palindrome analyser can be accessed at http://bioinformatics.ibp.cz.

  11. Palindrome analyser - A new web-based server for predicting and evaluating inverted repeats in nucleotide sequences.

    PubMed

    Brázda, Václav; Kolomazník, Jan; Lýsek, Jiří; Hároníková, Lucia; Coufal, Jan; Št'astný, Jiří

    2016-09-30

    DNA cruciform structures play an important role in the regulation of natural processes including gene replication and expression, as well as nucleosome structure and recombination. They have also been implicated in the evolution and development of diseases such as cancer and neurodegenerative disorders. Cruciform structures are formed by inverted repeats, and their stability is enhanced by DNA supercoiling and protein binding. They have received broad attention because of their important roles in biology. Computational approaches to study inverted repeats have allowed detailed analysis of genomes. However, currently there are no easily accessible and user-friendly tools that can analyse inverted repeats, especially among long nucleotide sequences. We have developed a web-based server, Palindrome analyser, which is a user-friendly application for analysing inverted repeats in various DNA (or RNA) sequences including genome sequences and oligonucleotides. It allows users to search and retrieve desired gene/nucleotide sequence entries from the NCBI databases, and provides data on length, sequence, locations and energy required for cruciform formation. Palindrome analyser also features an interactive graphical data representation of the distribution of the inverted repeats, with options for sorting according to the length of inverted repeat, length of loop, and number of mismatches. Palindrome analyser can be accessed at http://bioinformatics.ibp.cz. PMID:27603574

  12. 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

  13. 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.

  14. Inverted Low-Copy Repeats and Genome Instability—A Genome-Wide Analysis

    PubMed Central

    Dittwald, Piotr; Gambin, Tomasz; Gonzaga-Jauregui, Claudia; Carvalho, Claudia M.B.; Lupski, James R.; Stankiewicz, Paweł; Gambin, Anna

    2013-01-01

    Inverse paralogous low-copy repeats (IP-LCRs) can cause genome instability by nonallelic homologous recombination (NAHR)-mediated balanced inversions. When disrupting a dosage-sensitive gene(s), balanced inversions can lead to abnormal phenotypes. We delineated the genome-wide distribution of IP-LCRs >1 kB in size with >95% sequence identity and mapped the genes, potentially intersected by an inversion, that overlap at least one of the IP-LCRs. Remarkably, our results show that 12.0% of the human genome is potentially susceptible to such inversions and 942 genes, 99 of which are on the X chromosome, are predicted to be disrupted secondary to such an inversion! In addition, IP-LCRs larger than 800 bp with at least 98% sequence identity (duplication/triplication facilitating IP-LCRs, DTIP-LCRs) were recently implicated in the formation of complex genomic rearrangements with a duplication-inverted triplication–duplication (DUP-TRP/INV-DUP) structure by a replication-based mechanism involving a template switch between such inverted repeats. We identified 1,551 DTIP-LCRs that could facilitate DUP-TRP/INV-DUP formation. Remarkably, 1,445 disease-associated genes are at risk of undergoing copy-number gain as they map to genomic intervals susceptible to the formation of DUP-TRP/INV-DUP complex rearrangements. We implicate inverted LCRs as a human genome architectural feature that could potentially be responsible for genomic instability associated with many human disease traits. PMID:22965494

  15. Structures of ω repressors bound to direct and inverted DNA repeats explain modulation of transcription

    PubMed Central

    Weihofen, Wilhelm Andreas; Cicek, Aslan; Pratto, Florencia; Alonso, Juan Carlos; Saenger, Wolfram

    2006-01-01

    Repressor ω regulates transcription of genes required for copy number control, accurate segregation and stable maintenance of inc18 plasmids hosted by Gram-positive bacteria. ω belongs to homodimeric ribbon-helix-helix (RHH2) repressors typified by a central, antiparallel β-sheet for DNA major groove binding. Homodimeric ω2 binds cooperatively to promotors with 7 to 10 consecutive non-palindromic DNA heptad repeats (5′-A/TATCACA/T-3′, symbolized by →) in palindromic inverted, converging (→←) or diverging (←→) orientation and also, unique to ω2 and contrasting other RHH2 repressors, to non-palindromic direct (→→) repeats. Here we investigate with crystal structures how ω2 binds specifically to heptads in minimal operators with (→→) and (→←) repeats. Since the pseudo-2-fold axis relating the monomers in ω2 passes the central C–G base pair of each heptad with ∼0.3 Å downstream offset, the separation between the pseudo-2-fold axes is exactly 7 bp in (→→), ∼0.6 Å shorter in (→←) but would be ∼0.6 Å longer in (←→). These variations grade interactions between adjacent ω2 and explain modulations in cooperative binding affinity of ω2 to operators with different heptad orientations. PMID:16528102

  16. 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.

  17. Development of resistant transgenic soybeans with inverted repeat-coat protein genes of soybean dwarf virus.

    PubMed

    Tougou, Makoto; Furutani, Noriyuki; Yamagishi, Noriko; Shizukawa, Yoshiaki; Takahata, Yoshihito; Hidaka, Soh

    2006-11-01

    In an attempt to generate soybean plants resistant to soybean dwarf virus (SbDV), we transformed a construct containing inverted repeat-SbDV coat protein (CP) genes spaced by beta-glucuronidase (GUS) sequences into soybean somatic embryos via microprojectile bombardment. Three T(0) plants with an introduced CP gene were obtained, and one generated T(1) seeds. The presence of the transgene in T(1) plants was confirmed by PCR and Southern blot hybridization analysis, but expression of CP was not detected by northern blot hybridization analysis. Two months after inoculation of SbDV by aphid, T(2) plants contained little SbDV-specific RNA and remained symptomless. These plants contained SbDV-CP-specific siRNA. These results suggest that the T(2) plants achieved resistance to SbDV by an RNA-silencing-mediated process.

  18. 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

  19. 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

  20. 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

  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. Short inverted repeats initiate gene amplification through the formation of a large DNA palindrome in mammalian cells.

    PubMed

    Tanaka, Hisashi; Tapscott, Stephen J; Trask, Barbara J; Yao, Meng-Chao

    2002-06-25

    Gene amplification is a common form of genomic instability in a wide variety of organisms and is often associated with tumor progression in mammals. One striking feature of many amplified genes is their organization as large inverted duplications (palindromes). Here, we describe a molecular mechanism for palindrome formation in mammalian cells that is also conserved in protists. We introduced a short (79 or 229 bp) inverted repeat into the genome of Chinese hamster ovary cells and showed that it promoted the formation of a large DNA palindrome after an adjacent DNA double-strand break. This finding suggests that short inverted repeats in the mammalian genome can have a critical role in the initiation of gene amplification. This specific mechanism may provide a novel target for cancer therapies.

  3. 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.

  4. Graft-transmissible movement of inverted-repeat-induced siRNA signals into flowers.

    PubMed

    Zhang, Wenna; Kollwig, Gregor; Stecyk, Ewelina; Apelt, Federico; Dirks, Rob; Kragler, Friedrich

    2014-10-01

    In plants, small interfering RNAs (siRNA) and microRNAs move to distant tissues where they control numerous developmental and physiological processes such as morphogenesis and stress responses. Grafting techniques and transient expression systems have been employed to show that sequence-specific siRNAs with a size of 21-24 nucleotides traffic to distant organs. We used inverted-repeat constructs producing siRNA targeting the meiosis factor DISRUPTED MEIOTIC cDNA 1 (DMC1) and GFP to test whether silencing signals move into meiotically active tissues. In grafted Nicotiana tabacum, a transgenic DMC1 siRNA signal made in source tissues preferably entered the anthers formed in the first flowers. Here, the DMC1 siRNA interfered with meiotic progression and, consequently, the flowers were at least partially sterile. In agro-infiltrated N. benthamiana plants, a GFP siRNA signal produced in leaves was allocated and active in most flower tissues including anthers. In hypocotyl-grafted Arabidopsis thaliana plants, the DMC1 silencing signal consistently appeared in leaves, petioles, and stem, and only a small number of plants displayed DMC1 siRNA signals in flowers. In all three tested plant species the systemic silencing signal penetrated male sporogenic tissues suggesting that plants harbour an endogenous long-distance small RNA transport pathway facilitating siRNA signalling into meiotically active cells.

  5. 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

  6. ATP-dependent specific binding of Tn3 transposase to Tn3 inverted repeats

    NASA Astrophysics Data System (ADS)

    Wishart, W. L.; Broach, J. R.; Ohtsubo, E.

    1985-04-01

    Transposons are discrete segments of DNA which are capable of moving from one site in a genome to many different sites1,2. Tn3 is a prokaryotic transposon which is 4,957 base pairs (bp) long and encodes a transposase protein which is essential for transposition3-7. We report here a simple method for purifying Tn3 transposase and demonstrate that the transposase protein binds specifically to the ends of the Tn3 transposon in an ATP-dependent manner. The transposase protein binds to linear double-stranded DNA both nonspecifically and specifically; the nonspecific DNA binding activity is sensitive to challenge with heparin. Site-specific DNA binding to the ends (inverted repeats) of Tn3 is observed only when binding is performed in the presence of ATP; this ATP-dependent site-specific DNA binding activity is resistant to heparin challenge. Our results indicate that ATP qualitatively alters the DNA binding activity of the transposase protein so that the protein is able to bind specifically to the ends of the Tn3 transposon.

  7. 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.

  8. Bioinformatic analyses of sense and antisense expression from terminal inverted repeat transposons in Drosophila somatic cells.

    PubMed

    Harrington, Andrew W; Steiniger, Mindy

    2016-01-01

    Understanding regulation of transposon movement in somatic cells is important as mobile elements can cause detrimental genomic rearrangements. Generally, transposons move via one of 2 mechanisms; retrotransposons utilize an RNA intermediate, therefore copying themselves and amplifying throughout the genome, while terminal inverted repeat transposons (TIR Tns) excise DNA sequences from the genome and integrate into a new location. Our recently published work indicates that retrotransposons in Drosophila tissue culture cells are actively transcribed in the antisense direction. Our data support a model in which convergent transcription of retrotransposons from intra element transcription start sites results in complementary RNAs that hybridize to form substrates for Dicer-2, the endogenous small interfering (esi)RNA generating enzyme. Here, we extend our previous analysis to TIR Tns. In contrast to retrotransposons, our data show that antisense TIR Tn RNAs result from transcription of intronic TIR Tns oriented antisense to their host genes. Also, disproportionately less esiRNAs are generated from TIR transcripts than from retrotransposons and transcription of very few individual TIR Tns could be confirmed. Collectively, these data support a model in which TIR Tns are regulated at the level of Transposase production while retrotransposons are regulated with esiRNA post-transcriptional mechanisms in Drosophila somatic cells. PMID:26986720

  9. A Gaijin-like miniature inverted repeat transposable element is mobilized in rice during cell differentiation

    PubMed Central

    2012-01-01

    Background Miniature inverted repeat transposable element (MITE) is one type of transposable element (TE), which is largely found in eukaryotic genomes and involved in a wide variety of biological events. However, only few MITEs were proved to be currently active and their physiological function remains largely unknown. Results We found that the amplicon discrepancy of a gene locus LOC_Os01g0420 in different rice cultivar genomes was resulted from the existence of a member of Gaijin-like MITEs (mGing). This result indicated that mGing transposition was occurred at this gene locus. By using a modified transposon display (TD) analysis, the active transpositions of mGing were detected in rice Jiahua No. 1 genome under three conditions: in seedlings germinated from the seeds received a high dose γ-ray irradiation, in plantlets regenerated from anther-derived calli and from scutellum-derived calli, and were confirmed by PCR validation and sequencing. Sequence analysis revealed that single nucleotide polymorphisms (SNPs) or short additional DNA sequences at transposition sites post mGing transposition. It suggested that sequence modification was possibly taken place during mGing transposition. Furthermore, cell re-differentiation experiment showed that active transpositions of both mGing and mPing (another well studied MITE) were identified only in regenerated plantlets. Conclusions It is for the first time that mGing active transposition was demonstrated under γ-ray irradiation or in cell re-differentiation process in rice. This newly identified active MITE will provide a foundation for further analysis of the roles of MITEs in biological process. PMID:22500940

  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. 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.

  12. 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

  13. 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.

  14. 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

  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. Recombination Analysis of Herpes Simplex Virus 1 Reveals a Bias toward GC Content and the Inverted Repeat Regions

    PubMed Central

    Lee, Kyubin; Kolb, Aaron W.; Sverchkov, Yuriy; Cuellar, Jacqueline A.; Craven, Mark

    2015-01-01

    ABSTRACT Herpes simplex virus 1 (HSV-1) causes recurrent mucocutaneous ulcers and is the leading cause of infectious blindness and sporadic encephalitis in the United States. HSV-1 has been shown to be highly recombinogenic; however, to date, there has been no genome-wide analysis of recombination. To address this, we generated 40 HSV-1 recombinants derived from two parental strains, OD4 and CJ994. The 40 OD4-CJ994 HSV-1 recombinants were sequenced using the Illumina sequencing system, and recombination breakpoints were determined for each of the recombinants using the Bootscan program. Breakpoints occurring in the terminal inverted repeats were excluded from analysis to prevent double counting, resulting in a total of 272 breakpoints in the data set. By placing windows around the 272 breakpoints followed by Monte Carlo analysis comparing actual data to simulated data, we identified a recombination bias toward both high GC content and intergenic regions. A Monte Carlo analysis also suggested that recombination did not appear to be responsible for the generation of the spontaneous nucleotide mutations detected following sequencing. Additionally, kernel density estimation analysis across the genome found that the large, inverted repeats comprise a recombination hot spot. IMPORTANCE Herpes simplex virus 1 (HSV-1) virus is the leading cause of sporadic encephalitis and blinding keratitis in developed countries. HSV-1 has been shown to be highly recombinogenic, and recombination itself appears to be a significant component of genome replication. To date, there has been no genome-wide analysis of recombination. Here we present the findings of the first genome-wide study of recombination performed by generating and sequencing 40 HSV-1 recombinants derived from the OD4 and CJ994 parental strains, followed by bioinformatics analysis. Recombination breakpoints were determined, yielding 272 breakpoints in the full data set. Kernel density analysis determined that the large

  18. A Drosophila protein homologous to the human p70 Ku autoimmune antigen interacts with the P transposable element inverted repeats.

    PubMed Central

    Beall, E L; Admon, A; Rio, D C

    1994-01-01

    P transposable elements in Drosophila are mobilized via a cut-and-paste mechanism. This mode of transposition requires repair of both a double-strand break at the donor DNA site and gapped DNA at the target site. Biochemical studies have identified a cellular non-P element-encoded DNA binding protein, termed the inverted repeat binding protein (IRBP), that specifically interacts with the outer half of the 31-bp terminal inverted repeats. Protein sequence information was used to isolate cDNA clones encoding IRBP. Sequence analysis shows that IRBP is related to the 70-kDa subunit of the human Ku autoimmune antigen. The mammalian Ku antigen binds free DNA termini and has been implicated in immunoglobulin VDJ recombination, DNA repair, and transcription. In addition, Ku is the DNA binding subunit of the double-strand DNA-dependent protein kinase. Cytogenetic mapping indicates that the IRBP gene maps to chromosomal position 86E on the right arm of the third chromosome. Images Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:7809101

  19. Wolffish antifreeze protein genes are primarily organized as tandem repeats that each contain two genes in inverted orientation.

    PubMed Central

    Scott, G K; Hayes, P H; Fletcher, G L; Davies, P L

    1988-01-01

    The antifreeze protein genes of the wolffish (Anarhichas lupus) constitute a large multigene family of 80 to 85 copies, which can be classified into two sets. One-third of the genes were linked but irregularly spaced. The other two-thirds were organized as 8-kilobase-pair (kbp) tandem direct repeats that each contained two genes in inverted orientation; DNA sequence analysis suggests that both genes are functional. Except for a single region specific to each gene, the genes and their immediate flanking sequences were 99.2% identical. This degree of identity ended soon after a putative transcription termination sequence; as the 3' ends of the genes were only 1.3 kbp apart, these sequences might confer mutual protection from interference by transcriptional runoff. A Southern blot of wolffish DNA restricted with enzymes that do not cut within the tandem repeats indicated that the repeats were clustered in groups of six or more. The organization of antifreeze protein genes in the wolffish was very similar to that in the unrelated winter flounder, which produces a completely different antifreeze. This similarity might reflect common dynamics by which their progenitors adapted to life in ice-laden sea water. Images PMID:2851724

  20. Construction of mismatched inverted repeat (IR) silencing vectors for maximizing IR stability and effective gene silencing in plants.

    PubMed

    Rey, M E Chrissie; Harmse, Johan; Taylor, Sarah H; Arbuthnot, Patrick; Weinberg, Marc S

    2015-01-01

    Inverted repeat (IR) RNA silencing vectors containing homologous fragments of target endogenous plant genes, or pathogen genes, are the most widely used vectors to either study the function of genes involved in biotic stress or silence pathogens to induce plant resistance, respectively. 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 IR constructs during cloning and plant transformation. We have therefore developed a robust method for the production of long IR vector constructs by introducing base pair mismatches in the form of cytosine to thymine mutations on the sense arm by exposure to sodium bisulfite prior to assembly of the IR. PMID:25740374

  1. Hot Fusion: an efficient method to clone multiple DNA fragments as well as inverted repeats without ligase.

    PubMed

    Fu, Changlin; Donovan, William P; Shikapwashya-Hasser, Olga; Ye, Xudong; Cole, Robert H

    2014-01-01

    Molecular cloning is utilized in nearly every facet of biological and medical research. We have developed a method, termed Hot Fusion, to efficiently clone one or multiple DNA fragments into plasmid vectors without the use of ligase. The method is directional, produces seamless junctions and is not dependent on the availability of restriction sites for inserts. Fragments are assembled based on shared homology regions of 17-30 bp at the junctions, which greatly simplifies the construct design. Hot Fusion is carried out in a one-step, single tube reaction at 50 °C for one hour followed by cooling to room temperature. In addition to its utility for multi-fragment assembly Hot Fusion provides a highly efficient method for cloning DNA fragments containing inverted repeats for applications such as RNAi. The overall cloning efficiency is in the order of 90-95%.

  2. 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/.

  3. Spatiotemporal variations of interplate slip rates in northeast Japan inverted from recurrence intervals of repeating earthquakes

    NASA Astrophysics Data System (ADS)

    Nomura, Shunichi; Ogata, Yosihiko; Uchida, Naoki; Matsu'ura, Mitsuhiro

    2016-10-01

    Repeating earthquakes, the sequence of stress accumulation and release at isolated small asperities on a plate interface, can be regarded as a renewal process in statistics. From such a point of view, we modeled a sequence of repeating earthquakes and developed an objective Bayesian method to estimate the space-time distribution of interplate slip rates from the recurrence intervals of repeating earthquakes. The space-time distribution of slip rates is represented by the superposition of tri-cubic B-splines. The knots of B-splines in time are unequally allocated for representing coseismic abrupt and postseismic rapid changes in slip rates. In addition, to avoid overfitting, smoothness constraints are imposed and their optimal weights are determined by Akaike's Bayesian Information Criterion (ABIC). We applied this method to the complete data set of repeating earthquakes in northeast Japan for about 18 years before the 2011 Tohoku-oki earthquake, and revealed spatiotemporal variations of interplate slip rates off the Hokkaido-Tohoku region, where the 1994 Sanriku-oki (M7.6), 2003 Tokachi-oki (M8.0), 2004 Kushiro-oki (M7.1), and 2008 Ibaraki-oki (M7.0) earthquakes occurred. First, we confirmed the reciprocal correlation between the spatial distribution of average slip rates for a seismically calm period (1996-2000) and that of average slip-deficit rates, which has been estimated from GPS array data. Then, we examined the temporal variations of slip rates associated with the large interplate earthquakes in detail.

  4. Identification of multiple binding sites for the THAP domain of the Galileo transposase in the long terminal inverted-repeats.

    PubMed

    Marzo, Mar; Liu, Danxu; Ruiz, Alfredo; Chalmers, Ronald

    2013-08-01

    Galileo is a DNA transposon responsible for the generation of several chromosomal inversions in Drosophila. In contrast to other members of the P-element superfamily, it has unusually long terminal inverted-repeats (TIRs) that resemble those of Foldback elements. To investigate the function of the long TIRs we derived consensus and ancestral sequences for the Galileo transposase in three species of Drosophilids. Following gene synthesis, we expressed and purified their constituent THAP domains and tested their binding activity towards the respective Galileo TIRs. DNase I footprinting located the most proximal DNA binding site about 70 bp from the transposon end. Using this sequence we identified further binding sites in the tandem repeats that are found within the long TIRs. This suggests that the synaptic complex between Galileo ends may be a complicated structure containing higher-order multimers of the transposase. We also attempted to reconstitute Galileo transposition in Drosophila embryos but no events were detected. Thus, although the limited numbers of Galileo copies in each genome were sufficient to provide functional consensus sequences for the THAP domains, they do not specify a fully active transposase. Since the THAP recognition sequence is short, and will occur many times in a large genome, it seems likely that the multiple binding sites within the long, internally repetitive, TIRs of Galileo and other Foldback-like elements may provide the transposase with its binding specificity.

  5. 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...

  6. 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, ...

  7. A novel method to convert a DNA fragment inserted into a plasmid to an inverted repeat structure.

    PubMed

    Tomimoto, Kazuya; Fujita, Kosuke; Ishibashi, Jun; Imanishi, Shigeo; Yamakawa, Minoru; Tanaka, Hiromitsu

    2012-01-01

    Transfection of an expression plasmid possessing inverted repeat (IR) DNA into cultured cells leads to the overexpression of hairpin RNA and efficient suppression of target gene expression. Such DNA vector-based RNA interference (RNAi) is widely used for characterizing genes of interest in cultured cell lines. In this study, we developed a new method to convert an inserted DNA fragment (IDF) in specially designed plasmid vectors into an IR structure by using nicking endonucleases and BcaBEST DNA polymerase. This method consists of the following steps: (1) linearization of the plasmid with a nick by using a restriction enzyme and a nicking endonuclease, (2) formation of the hairpin-loop DNA at the end near the IDF of the linearized plasmid, (3) insertion of a nick at the other end of the IDF by a nicking endonuclease, (4) execution of the strand displacement reaction from the nick to synthesize IR DNA, and (5) self-ligation of the linear double-stranded DNA. The IR DNA containing expression plasmids constructed by this method effectively induced target-specific RNAi in a silkworm cell line. We further established a method to purify expression plasmids containing IR DNA. Our new methods provide techniques for the construction of long hairpin RNA (lhRNA) expression plasmids for silencing specific genes in silkworms and other organisms, and offer a fundamental methodology for constructing an lhRNA expression library from a cDNA plasmid library. PMID:21516519

  8. 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.

  9. 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

  10. 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

  11. 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

  12. 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.

  13. A novel method to convert a DNA fragment inserted into a plasmid to an inverted repeat structure.

    PubMed

    Tomimoto, Kazuya; Fujita, Kosuke; Ishibashi, Jun; Imanishi, Shigeo; Yamakawa, Minoru; Tanaka, Hiromitsu

    2012-01-01

    Transfection of an expression plasmid possessing inverted repeat (IR) DNA into cultured cells leads to the overexpression of hairpin RNA and efficient suppression of target gene expression. Such DNA vector-based RNA interference (RNAi) is widely used for characterizing genes of interest in cultured cell lines. In this study, we developed a new method to convert an inserted DNA fragment (IDF) in specially designed plasmid vectors into an IR structure by using nicking endonucleases and BcaBEST DNA polymerase. This method consists of the following steps: (1) linearization of the plasmid with a nick by using a restriction enzyme and a nicking endonuclease, (2) formation of the hairpin-loop DNA at the end near the IDF of the linearized plasmid, (3) insertion of a nick at the other end of the IDF by a nicking endonuclease, (4) execution of the strand displacement reaction from the nick to synthesize IR DNA, and (5) self-ligation of the linear double-stranded DNA. The IR DNA containing expression plasmids constructed by this method effectively induced target-specific RNAi in a silkworm cell line. We further established a method to purify expression plasmids containing IR DNA. Our new methods provide techniques for the construction of long hairpin RNA (lhRNA) expression plasmids for silencing specific genes in silkworms and other organisms, and offer a fundamental methodology for constructing an lhRNA expression library from a cDNA plasmid library.

  14. 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

  15. 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.

  16. A genome-wide view of miniature inverted-repeat transposable elements (MITEs) in rice, Oryza sativa ssp. japonica.

    PubMed

    Oki, Nobuhiko; Yano, Kentaro; Okumoto, Yutaka; Tsukiyama, Takuji; Teraishi, Masayoshi; Tanisaka, Takatoshi

    2008-08-01

    Transposable elements (TEs) have played important roles in the evolution of genes and genomes of higher eukaryotes. Among the TEs in the rice genome, miniature inverted-repeat transposable elements (MITEs) exist at the highest copy number. Some of MITEs in the rice genome contain poly(A) signals and putative cis-acting regulatory domains. Insertion events of such MITEs may have caused many structural and functional changes of genomes. The genome-wide examination of MITE-derived sequences could elucidate the contribution of MITEs to gene evolution. Here we report on the MITEs in the rice genome that have contributed to the emergence of novel genes and the expansion of the sequence diversity of the genome and mRNAs. Of the MITE-derived sequences, approximately 6000 were found in gene regions (exons and introns) and 67,000 in intergenic regions. In gene regions, most MITEs are located in introns rather than exons. For over 300 protein-coding genes, coding sequences, poly(A) sites, transcription start sites, and splicing sites overlap with MITEs. These sequence alterations via MITE insertions potentially affect the biological functions of gene products. Many MITE insertions also exist in 5'-untranslated regions (UTRs), 3'-UTRs, and in the proximity of genes. Although mutations in these non-protein coding regions do not alter protein sequences, these regions have key roles for gene regulation. Moreover, MITE family sequences (Tourist, Stowaway, and others) are unevenly distributed in introns. Our findings suggest that MITEs may have contributed to expansion of genome diversity by causing alterations not only in gene functions but also in regulation of many genes. PMID:18931457

  17. 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

  18. Integration of promoters, inverted repeat sequences and proteomic data into a model for high silencing efficiency of coeliac disease related gliadins in bread wheat

    PubMed Central

    2013-01-01

    Background Wheat gluten has unique nutritional and technological characteristics, but is also a major trigger of allergies and intolerances. One of the most severe diseases caused by gluten is coeliac disease. The peptides produced in the digestive tract by the incomplete digestion of gluten proteins trigger the disease. The majority of the epitopes responsible reside in the gliadin fraction of gluten. The location of the multiple gliadin genes in blocks has to date complicated their elimination by classical breeding techniques or by the use of biotechnological tools. As an approach to silence multiple gliadin genes we have produced 38 transgenic lines of bread wheat containing combinations of two endosperm-specific promoters and three different inverted repeat sequences to silence three fractions of gliadins by RNA interference. Results The effects of the RNA interference constructs on the content of the gluten proteins, total protein and starch, thousand seed weights and SDSS quality tests of flour were analyzed in these transgenic lines in two consecutive years. The characteristics of the inverted repeat sequences were the main factor that determined the efficiency of silencing. The promoter used had less influence on silencing, although a synergy in silencing efficiency was observed when the two promoters were used simultaneously. Genotype and the environment also influenced silencing efficiency. Conclusions We conclude that to obtain wheat lines with an optimum reduction of toxic gluten epitopes one needs to take into account the factors of inverted repeat sequences design, promoter choice and also the wheat background used. PMID:24044767

  19. The complete chloroplast genome sequence of Taxus chinensis var. mairei (Taxaceae): loss of an inverted repeat region and comparative analysis with related species.

    PubMed

    Zhang, Yanzhen; Ma, Ji; Yang, Bingxian; Li, Ruyi; Zhu, Wei; Sun, Lianli; Tian, Jingkui; Zhang, Lin

    2014-05-01

    Taxus chinensis var. mairei (Taxaceae) is a domestic variety of yew species in local China. This plant is one of the sources for paclitaxel, which is a promising antineoplastic chemotherapy drugs during the last decade. We have sequenced the complete nucleotide sequence of the chloroplast (cp) genome of T. chinensis var. mairei. The T. chinensis var. mairei cp genome is 129,513 bp in length, with 113 single copy genes and two duplicated genes (trnI-CAU, trnQ-UUG). Among the 113 single copy genes, 9 are intron-containing. Compared to other land plant cp genomes, the T. chinensis var. mairei cp genome has lost one of the large inverted repeats (IRs) found in angiosperms, fern, liverwort, and gymnosperm such as Cycas revoluta and Ginkgo biloba L. Compared to related species, the gene order of T. chinensis var. mairei has a large inversion of ~110kb including 91 genes (from rps18 to accD) with gene contents unarranged. Repeat analysis identified 48 direct and 2 inverted repeats 30 bp long or longer with a sequence identity greater than 90%. Repeated short segments were found in genes rps18, rps19 and clpP. Analysis also revealed 22 simple sequence repeat (SSR) loci and almost all are composed of A or T.

  20. The complete chloroplast genome sequence of Cephalotaxus oliveri (Cephalotaxaceae): evolutionary comparison of cephalotaxus chloroplast DNAs and insights into the loss of inverted repeat copies in gymnosperms.

    PubMed

    Yi, Xuan; Gao, Lei; Wang, Bo; Su, Ying-Juan; Wang, Ting

    2013-01-01

    We have determined the complete chloroplast (cp) genome sequence of Cephalotaxus oliveri. The genome is 134,337 bp in length, encodes 113 genes, and lacks inverted repeat (IR) regions. Genome-wide mutational dynamics have been investigated through comparative analysis of the cp genomes of C. oliveri and C. wilsoniana. Gene order transformation analyses indicate that when distinct isomers are considered as alternative structures for the ancestral cp genome of cupressophyte and Pinaceae lineages, it is not possible to distinguish between hypotheses favoring retention of the same IR region in cupressophyte and Pinaceae cp genomes from a hypothesis proposing independent loss of IRA and IRB. Furthermore, in cupressophyte cp genomes, the highly reduced IRs are replaced by short repeats that have the potential to mediate homologous recombination, analogous to the situation in Pinaceae. The importance of repeats in the mutational dynamics of cupressophyte cp genomes is also illustrated by the accD reading frame, which has undergone extreme length expansion in cupressophytes. This has been caused by a large insertion comprising multiple repeat sequences. Overall, we find that the distribution of repeats, indels, and substitutions is significantly correlated in Cephalotaxus cp genomes, consistent with a hypothesis that repeats play a role in inducing substitutions and indels in conifer cp genomes.

  1. Noncoding sequences from the slowly evolving chloroplast inverted repeat in addition to rbcL data do not support gnetalean affinities of angiosperms.

    PubMed

    Goremykin, V; Bobrova, V; Pahnke, J; Troitsky, A; Antonov, A; Martin, W

    1996-02-01

    We developed PCR primers against highly conserved regions of the rRNA operon located within the inverted repeat of the chloroplast genome and used these to amplify the region spanning from the 3' terminus of the 23S rRNA gene to the 5' terminus of the 5S rRNA gene. The sequence of this roughly 500-bp region, which includes the 4.5S rRNA gene and two chloroplast intergenic transcribed spacer regions (cpITS2 and cpITS3), was determined from 20 angiosperms, 7 gymnosperms, and 16 ferns (21,700 bp). Sequences for the large subunit of ribulose bisphosphate carboxylase/oxygenase (rbcL) from the same or confamilial genera were analyzed in both separate and combined data sets. Due to the low substitution rate in the inverted repeat region, noncoding sequences in the cpITS region are not saturated with substitutions, in contrast to synonymous sites in rbcL, which are shown to evolve roughly six times faster than noncoding cpITS sequences. Several length polymorphisms with very clear phylogenetic distributions were detected in the data set. Results of phylogenetic analyses provide very strong bootstrap support for monophyly of both spermatophytes and angiosperms. No support for a sister group relationship between Gnetales and angiosperms in either cpITS or rbcL data was found. Rather, weak bootstrap support for monophyly of gymnosperms studied and for a basal position for the aquatic angiosperm Nymphaea among angiosperms studied was observed. Noncoding sequences from the inverted repeat region of chloroplast DNA appear suitable for study of land plant evolution.

  2. 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.

  3. 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

  4. 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.

  5. The complete chloroplast genome sequence of Mahonia bealei (Berberidaceae) reveals a significant expansion of the inverted repeat and phylogenetic relationship with other angiosperms.

    PubMed

    Ma, Ji; Yang, Bingxian; Zhu, Wei; Sun, Lianli; Tian, Jingkui; Wang, Xumin

    2013-10-10

    Mahonia bealei (Berberidaceae) is a frequently-used traditional Chinese medicinal plant with efficient anti-inflammatory ability. This plant is one of the sources of berberine, a new cholesterol-lowering drug with anti-diabetic activity. We have sequenced the complete nucleotide sequence of the chloroplast (cp) genome of M. bealei. The complete cp genome of M. bealei is 164,792 bp in length, and has a typical structure with large (LSC 73,052 bp) and small (SSC 18,591 bp) single-copy regions separated by a pair of inverted repeats (IRs 36,501 bp) of large size. The Mahonia cp genome contains 111 unique genes and 39 genes are duplicated in the IR regions. The gene order and content of M. bealei are almost unarranged which is consistent with the hypothesis that large IRs stabilize cp genome and reduce gene loss-and-gain probabilities during evolutionary process. A large IR expansion of over 12 kb has occurred in M. bealei, 15 genes (rps19, rpl22, rps3, rpl16, rpl14, rps8, infA, rpl36, rps11, petD, petB, psbH, psbN, psbT and psbB) have expanded to have an additional copy in the IRs. The IR expansion rearrangement occurred via a double-strand DNA break and subsequence repair, which is different from the ordinary gene conversion mechanism. Repeat analysis identified 39 direct/inverted repeats 30 bp or longer with a sequence identity ≥ 90%. Analysis also revealed 75 simple sequence repeat (SSR) loci and almost all are composed of A or T, contributing to a distinct bias in base composition. Comparison of protein-coding sequences with ESTs reveals 9 putative RNA edits and 5 of them resulted in non-synonymous modifications in rpoC1, rps2, rps19 and ycf1. Phylogenetic analysis using maximum parsimony (MP) and maximum likelihood (ML) was performed on a dataset composed of 65 protein-coding genes from 25 taxa, which yields an identical tree topology as previous plastid-based trees, and provides strong support for the sister relationship between Ranunculaceae and Berberidaceae

  6. 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

  7. 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

  8. 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.

  9. 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

  10. 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

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

    PubMed

    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.

  12. Extensive sequence divergence in the 3' inverted repeat of the chloroplast rbcL gene in non-flowering land plants and algae.

    PubMed

    Calie, P J; Manhart, J R

    1994-09-01

    A stem-loop region is present at the 3' terminus of the chloroplast rbcL mRNA in all taxa surveyed to date. In spinach, this structure has been shown by others to be involved in modulating transcript stability and correct 3' terminus processing, and is a conserved feature of other flowering plant rbcL mRNAs. In Chlamydomonas reinhardtii, an analogous structure has been shown by others to serve as a transcription terminator. Our sequencing data have shown that this region is highly divergent in several non-flowering land plants, as evidenced by representatives from the ferns, conifers, 'fern-allies' and liverworts. To extend our analysis, a computer-assisted survey of the stem-loop region of the 3' flanking region of published chloroplast rbcL genes was undertaken. The flowering plant rbcL inverted repeats (IR) were remarkably conserved in sequence, allowing for precise multiple alignments of both monocot and dicot sequences within a single matrix. Surprisingly, sequences obtained from non-flowering land plants, algae, photosynthetic protists and photosynthetic prokaryotes were extremely variant, in terms of both sequence composition and thermodynamic parameters.

  13. 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

  14. Binding of a sequence-specific single-stranded DNA-binding factor to the simian virus 40 core origin inverted repeat domain is cell cycle regulated.

    PubMed Central

    Carmichael, E P; Roome, J M; Wahl, A F

    1993-01-01

    The inverted repeat domain (IR domain) within the simian virus 40 origin of replication is the site of initial DNA melting prior to the onset of DNA synthesis. The domain had previously been shown to be bound by a cellular factor in response to DNA damage. We demonstrate that two distinct cellular components bind opposite strands of the IR domain. Replication protein A (RPA), previously identified as a single-stranded DNA binding protein required for origin-specific DNA replication in vitro, is shown to have a preference for the pyrimidine-rich strand. A newly described component, IR factor B (IRF-B), specifically recognizes the opposite strand. IRF-B binding activity in nuclear extract varies significantly with cell proliferation and the cell cycle, so that binding of IRF-B to the IR domain is negatively correlated with the onset of DNA synthesis. Loss of IRF-B binding from the nucleus also occurs in response to cellular DNA damage. UV cross-linking indicates that the core binding component of IRF-B is a protein of ca. 34 kDa. We propose that RPA and IRF-B bind opposite strands of the IR domain and together may function in the regulation of origin activation. Images PMID:8380226

  15. A 53-base-pair inverted repeat negatively regulates expression of the adjacent and divergently oriented cytochrome P450(BM-1) gene and its regulatory gene, bm1P1, in Bacillus megaterium.

    PubMed Central

    Shaw, G C; Sung, C C; Liu, C H; Kao, H S

    1997-01-01

    To study the role of the cis-acting element(s) in controlling the expression of the cytochrome P450(BM-1) gene and its upstream regulatory gene, bm1P1, in Bacillus megaterium, various deletion derivatives were constructed. A 53-bp inverted repeat located midway between the P450(BM-1) gene and bm1P1 gene was found in vivo to negatively regulate the expression of both genes, the regulation of which may occur at the transcriptional level. The promoter of the P450(BM-1), gene was also identified and found to be similar to those recognized by the sigmaA RNA polymerase of Bacillus subtilis. Possible mechanisms by which the 53-bp inverted repeat regulates the gene expression are discussed. PMID:8982010

  16. Loss of different inverted repeat copies from the chloroplast genomes of Pinaceae and cupressophytes and influence of heterotachy on the evaluation of gymnosperm phylogeny.

    PubMed

    Wu, Chung-Shien; Wang, Ya-Nan; Hsu, Chi-Yao; Lin, Ching-Ping; Chaw, Shu-Miaw

    2011-01-01

    The relationships among the extant five gymnosperm groups--gnetophytes, Pinaceae, non-Pinaceae conifers (cupressophytes), Ginkgo, and cycads--remain equivocal. To clarify this issue, we sequenced the chloroplast genomes (cpDNAs) from two cupressophytes, Cephalotaxus wilsoniana and Taiwania cryptomerioides, and 53 common chloroplast protein-coding genes from another three cupressophytes, Agathis dammara, Nageia nagi, and Sciadopitys verticillata, and a non-Cycadaceae cycad, Bowenia serrulata. Comparative analyses of 11 conifer cpDNAs revealed that Pinaceae and cupressophytes each lost a different copy of inverted repeats (IRs), which contrasts with the view that the same IR has been lost in all conifers. Based on our structural finding, the character of an IR loss no longer conflicts with the "gnepines" hypothesis (gnetophytes sister to Pinaceae). Chloroplast phylogenomic analyses of amino acid sequences recovered incongruent topologies using different tree-building methods; however, we demonstrated that high heterotachous genes (genes that have highly different rates in different lineages) contributed to the long-branch attraction (LBA) artifact, resulting in incongruence of phylogenomic estimates. Additionally, amino acid compositions appear more heterogeneous in high than low heterotachous genes among the five gymnosperm groups. Removal of high heterotachous genes alleviated the LBA artifact and yielded congruent and robust tree topologies in which gnetophytes and Pinaceae formed a sister clade to cupressophytes (the gnepines hypothesis) and Ginkgo clustered with cycads. Adding more cupressophyte taxa could not improve the accuracy of chloroplast phylogenomics for the five gymnosperm groups. In contrast, removal of high heterotachous genes from data sets is simple and can increase confidence in evaluating the phylogeny of gymnosperms. PMID:21933779

  17. Loss of different inverted repeat copies from the chloroplast genomes of Pinaceae and cupressophytes and influence of heterotachy on the evaluation of gymnosperm phylogeny.

    PubMed

    Wu, Chung-Shien; Wang, Ya-Nan; Hsu, Chi-Yao; Lin, Ching-Ping; Chaw, Shu-Miaw

    2011-01-01

    The relationships among the extant five gymnosperm groups--gnetophytes, Pinaceae, non-Pinaceae conifers (cupressophytes), Ginkgo, and cycads--remain equivocal. To clarify this issue, we sequenced the chloroplast genomes (cpDNAs) from two cupressophytes, Cephalotaxus wilsoniana and Taiwania cryptomerioides, and 53 common chloroplast protein-coding genes from another three cupressophytes, Agathis dammara, Nageia nagi, and Sciadopitys verticillata, and a non-Cycadaceae cycad, Bowenia serrulata. Comparative analyses of 11 conifer cpDNAs revealed that Pinaceae and cupressophytes each lost a different copy of inverted repeats (IRs), which contrasts with the view that the same IR has been lost in all conifers. Based on our structural finding, the character of an IR loss no longer conflicts with the "gnepines" hypothesis (gnetophytes sister to Pinaceae). Chloroplast phylogenomic analyses of amino acid sequences recovered incongruent topologies using different tree-building methods; however, we demonstrated that high heterotachous genes (genes that have highly different rates in different lineages) contributed to the long-branch attraction (LBA) artifact, resulting in incongruence of phylogenomic estimates. Additionally, amino acid compositions appear more heterogeneous in high than low heterotachous genes among the five gymnosperm groups. Removal of high heterotachous genes alleviated the LBA artifact and yielded congruent and robust tree topologies in which gnetophytes and Pinaceae formed a sister clade to cupressophytes (the gnepines hypothesis) and Ginkgo clustered with cycads. Adding more cupressophyte taxa could not improve the accuracy of chloroplast phylogenomics for the five gymnosperm groups. In contrast, removal of high heterotachous genes from data sets is simple and can increase confidence in evaluating the phylogeny of gymnosperms.

  18. Association between a Functional HLA-G 14-bp Insertion/deletion Polymorphism and Susceptibility to Autoimmune Diseases: A Meta-analysis.

    PubMed

    Lee, Y H; Bae, S-C

    2015-12-09

    The aim of this study was to determine whether a functional human leukocyte antigen-G (HLA-G) 14-bp insertion (I)/deletion (D) polymorphism is associated with susceptibility to autoimmune diseases. A meta-analysis was conducted to assess the association between an HLA-G 14-bp I/D polymorphism and autoimmune diseases using 1) allele contrast, as well as 2) recessive, 3) dominant, and 4) codominant models. Sixteen articles that included 20 comparative studies with 3,555 patients and 5,225 controls were included in the meta-analysis. These studies were performed on nine Caucasian, six South American, three Asian, one Arab, and one African population samples. Our meta-analysis revealed no association between autoimmune diseases and the HLA-G 14-bp I/D polymorphism [odds ratio (OR) for allele I = 1.055; 95% confidence interval (CI) = 0.963-1.156; p = 0.251)]. However, meta-analysis according to autoimmune disease type revealed an association between systemic lupus erythematosus (SLE) and the II+ID genotype of the HLA-G 14-bp I/D polymorphism (OR = 1.205; 95% CI = 1.036-1.403; p = 0.016). Furthermore, analysis using a codominant model revealed an association between this polymorphism and SLE (OR for ID vs. DD = 1.203; 95% CI = 1.024-1.413; p = 0.024). In contrast, our meta-analysis revealed no association between rheumatoid arthritis (RA), multiple sclerosis (MS), or Crohn's disease (CD) and the HLA-G 14-bp I/D polymorphism. This meta-analysis showed that the HLA-G 14-bp I/D polymorphism is associated with susceptibility to a subgroup of autoimmune diseases such as SLE, but not RA, MS, or CD. These results support the existence of an association between the HLA-G gene and a subgroup of autoimmune diseases.

  19. 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.

  20. Association of HLA-G promoter and 14-bp insertion-deletion variants with acute allograft rejection and end-stage renal disease.

    PubMed

    Misra, M K; Prakash, S; Kapoor, R; Pandey, S K; Sharma, R K; Agrawal, S

    2013-11-01

    The aim of this study was to investigate the HLA-G 14-bp insertion/deletion (I/D) polymorphism among end-stage renal disease (ESRD) patients. Cytomegalovirus (CMV) infection, acute allograft rejection (AR) and overall survival after renal transplantation was investigated in 300 ESRD patients and 302 age, sex and ethnicity-matched controls. Sequencing was performed to evaluate the impact of HLA-G promoter region single-nucleotide polymorphisms (SNPs) whereas semi-quantitative PCR method was used to determine the probable HLA-G expression pattern among ESRD and AR cases. Further, soluble human leukocyte antigen (HLA)-G (sHLA-G) expression levels were compared in AR vs non-AR cases in the light of HLA-G 14-bp I/D polymorphism. Increased risk was found for 14-bp D/D (deletion-DD) genotype and 14-bp D allele [DD: odds ratio (OR) = 1.46, 95% confidence interval (CI) = 1.03-2.06, P value = 0.0358; D: OR = 1.29, 95% CI = 1.03-1.62, P value = 0.0277], respectively for ESRD and CMV infection (DD: OR = 2.70, 95% CI = 1.45-5.05, P value = 0.0021; D: OR = 1.94, 95% CI = 1.22-3.08, P value = 0.0052). Nearly fourfold (OR = 3.62, 95%CI = 1.61-8.14, p = 0.0039) risk was observed for 14-bp I/I (insertion-II) genotype for AR. Survival analysis showed increased overall survival (OS) (AR or death) for 14-bp D/D genotype. HLA-G promoter region sequencing was carried out among 60 ESRD patients and 100 normal controls which showed increased risk for -964 G>A, -725 C>G/T and -486 A>C SNPs. -964 G>A and -725 C>G/T SNPs showed risk association for AR patients. High level of HLA-G transcripts was observed among non-AR patients. Further soluble HLA-G (sHLA-G) showed increased levels in ESRD patients (mean ± SEM; 62.16 ± 2.43 U/ml) as compared to controls (mean ± SEM; 21.06 ± 3.89 U/ml) (P = <0.0001). The 14-bp I/I, 14-bp I/D and 14-bp D/D genotypes showed significantly higher levels of sHLA-G among non-AR as

  1. 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

  2. The 14 bp Del/Ins HLA-G polymorphism is related with high blood pressure in acute coronary syndrome and type 2 diabetes mellitus.

    PubMed

    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 (OR(c) = 1.65, P = 0.02). The genetic recessive model showed similar findings (OR(c) = 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.

  3. 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

  4. Genetic polymorphism in HLA-G 3'UTR 14-bp ins/del and risk of cancer: a meta-analysis of case-control study.

    PubMed

    Li, Tao; Huang, Haohai; Liao, Dan; Ling, Huahuang; Su, Bingguang; Cai, Maode

    2015-08-01

    Accumulating evidence has suggested that the human leucocyte antigen-G (HLA-G) 14 bp ins/del polymorphism might be related to cancer susceptibility. However, epidemiologic findings have been inconsistent. Therefore, we performed a meta-analysis of case-control study to derive a more precise estimation of this association. Electronic databases were searched to identify all eligible studies of HLA-G 14 bp ins/del polymorphism and cancer risk. Odds ratios (ORs) with 95 % confidence intervals (CIs) were calculated to evaluate the strength of the association in fixed-effects model or random-effects model according to heterogeneity. Publication bias, sensitivity analysis and subgroup analyses based on cancer type, ethnicity, source of controls and sample size were also performed. A total of 14 case-control studies, involving 2,757 cases and 3,972 controls, were included in the present meta-analysis. The pooled analysis showed that there is no significant relationship between the HLA-G 14 bp ins/del polymorphism and cancer susceptibility under the genetic models (for the allele model del vs. ins: OR 1.13, 95 % CI 1.00-1.27; for the homozygote comparison model del/del vs. ins/ins: OR 1.22, 95 % CI 0.95-1.56; for the dominant model del/del + ins/del vs. ins/ins: OR 1.15, 95 % CI 0.94-1.42; for recessive model del/del vs. ins/del + ins/ins: OR 1.13, 95 % CI 0.96-1.34; respectively). Subgroup analyses indicated significant association among breast cancer, population based control and the large sample size group in some genetic models. Our investigations demonstrate that genotypes for the HLA-G 14 bp ins/del polymorphism may be not associated with overall cancer risk. In a subgroup meta-analysis, however, HLA-G 14-bp ins/del polymorphism might contribute to breast cancer susceptibility.

  5. TamiR1123 originated from a family of miniature inverted-repeat transposable elements (MITE) including one inserted in the Vrn-A1a promoter in wheat.

    PubMed

    Yu, Ming; Carver, Brett F; Yan, Liuling

    2014-02-01

    More than half of spring wheat cultivars have a dominant Vrn-A1a allele that has an insertion of a miniature inverted-repeat transposable element (MITE) in its promoter. In this study, we found that the MITE present in the Vrn-A1a gene (MITE_VRN) is a nearly perfect palindrome and it can form highly stable hairpin loops when expressed as RNA. MITE_VRN also possessed sequences of a microRNA in Triticum aestivum (TamiR1123). The P(32) labeled TamiR1123 probe detected two RNA molecules on a small RNA gel blot, one expected for MITE_VRN, and the other expected for TamiR1123. These results demonstrated that MITE_VRN was expressed as RNAs and TamiR1123 was originated from the MITE_VRN family. The isogenic line TDD carrying the dominant Vrn-A1a allele with MITE_VRN showed higher TamiR1123 and Vrn-A1a transcript levels than the isogenic line TDE carrying the recessive vrn-A1a allele without MITE_VRN. TamiR1123 were greatly up-regulated by plant age but slightly down-regulated by low temperature and short days. These findings have pointed to alternative regulatory mechanisms for plant development governed by Vrn-A1a in spring wheat.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. Inverted drop testing and neck injury potential.

    PubMed

    Forrest, Stephen; Herbst, Brian; Meyer, Steve; Sances, Anthony; Kumaresan, Srirangam

    2003-01-01

    Inverted drop testing of vehicles is a methodology that has long been used by the automotive industry and researchers to test roof integrity and is currently being considered by the National Highway Traffic Safety Administration as a roof strength test. In 1990 a study was reported which involved 8 dolly rollover tests and 5 inverted drop tests. These studies were conducted with restrained Hybrid III instrumented Anthropometric Test Devices (ATD) in production and rollcaged vehicles to investigate the relationship between roof strength and occupant injury potential. The 5 inverted drop tests included in the study provided a methodology producing "repeatable roof impacts" exposing the ATDs to the similar impact environment as those seen in the dolly rollover tests. Authors have conducted two inverted drop test sets as part of an investigation of two real world rollover accidents. Hybrid-III ATD's were used in each test with instrumented head and necks. Both test sets confirm that reduction of roof intrusion and increased headroom can significantly enhance occupant protection. In both test pairs, the neck force of the dummy in the vehicle with less crush and more survival space was significantly lower. Reduced roof crush and dynamic preservation of the occupant survival space resulted in only minor occupant contact and minimal occupant loading, establishing a clear causal relationship between roof crush and neck injuries.

  11. 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…

  12. 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.

  13. 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.

  14. 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…

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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

  20. The bi-directional transcriptional promoters for the latency-relating transcripts of the pp38/pp24 mRNAs and the 1.8 kb-mRNA in the long inverted repeats of Marek's disease virus serotype 1 DNA are regulated by common promoter-specific enhancers.

    PubMed

    Shigekane, H; Kawaguchi, Y; Shirakata, M; Sakaguchi, M; Hirai, K

    1999-01-01

    In cell lines established from Marek's disease tumors, several viral transcripts are expressed and among them the products of pp38/pp24 mRNA and 1.8 kb-mRNA have been suggested to be involved in viral oncogenicity. The long inverted repeats of Marek's Disease virus serotype 1 (MDV1) genome contain closely located transcriptional promoters for phosphorylated protein pp38/pp24 and 1.8 kb-mRNA. These promoters initiate transcription in opposite directions and are separated only by a short enhancer region, which is likely to regulate both promoters simultaneously. We have analyzed the transcription activity of these promoters in MDV1 (Md5 strain) infected CEF by transient expression of CAT reporter genes and found that the promoters were in fact active in infected cells and the promoter for 1.8 kb-mRNA was more active than the pp38/pp24 promoter. Deletion analysis of the short enhancer region revealed that the 30 bp region overlapping the enhancer elements for 1.8 kb-mRNA was important for promoter activity for pp38/pp24. The gel shift analysis revealed that nuclear factor(s) actually bound to the overlapping 30 bp region. In addition, the activity of these promoters in infected cells varied with MDV strains. These results suggest that pp38/pp24 and 1.8 kb-mRNA promoters share a common regulatory sequence but a viral or a cellular factor(s) induced by viral infection regulates the promoter by distinct mechanisms.

  1. 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.

  2. 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

  3. 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...

  4. 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

  5. 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

  6. 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.

  7. 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...

  8. Accelerating development of advanced inverters :

    SciTech Connect

    Neely, Jason C.; Gonzalez, Sigifredo; Ropp, Michael; Schutz, Dustin

    2013-11-01

    The high penetration of utility interconnected photovoltaic (PV) systems is causing heightened concern over the effect that variable renewable generation will have on the electrical power system (EPS). These concerns have initiated the need to amend the utility interconnection standard to allow advanced inverter control functionalities that provide: (1) reactive power control for voltage support, (2) real power control for frequency support and (3) better tolerance of grid disturbances. These capabilities are aimed at minimizing the negative impact distributed PV systems may have on EPS voltage and frequency. Unfortunately, these advanced control functions may interfere with island detection schemes, and further development of advanced inverter functions requires a study of the effect of advanced functions on the efficacy of antiislanding schemes employed in industry. This report summarizes the analytical, simulation and experimental work to study interactions between advanced inverter functions and anti-islanding schemes being employed in distributed PV systems.

  9. 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.

  10. 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

  11. 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…

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. Security of Invertible Media Authentication Schemes Revisited

    NASA Astrophysics Data System (ADS)

    Dönigus, Daniel; Endler, Stefan; Fischlin, Marc; Hülsing, Andreas; Jäger, Patrick; Lehmann, Anja; Podrazhansky, Sergey; Schipp, Sebastian; Tews, Erik; Vowe, Sven; Walthart, Matthias; Weidemann, Frederik

    Dittmann, Katzenbeisser, Schallhart and Veith (SEC 2005) introduced the notion of invertible media authentication schemes, embedding authentication data in media objects via invertible watermarks. These invertible watermarks allow to recover the original media object (given a secret encryption key), as required for example in some medical applications where the distortion must be removable.

  17. 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…

  18. Single-electron differential-amplifier/inverter/non-inverter

    NASA Astrophysics Data System (ADS)

    Hung, K.-M.; Chen, C.-S.; Lin, T.-W.

    2006-07-01

    This work presents a single-electron differential amplifier (SEDA), inverter, and non-inverter based on the triple single-dopant quantum-dot (TSDQD) configuration, with new structures. The competition between the field-induced and confinement-related shifts in the wavefunction of the quantum dots yields a field-controllable spatial-displacement single-electron transistor. Deeper impurity levels in quantum dots promise a higher operating temperature and higher on/off current ratios. The I- V characteristics of the device, studied using the transfer Hamiltonian approach (THA), show that the ratio of on/off currents is >80 000 and the voltage gain is >4 eV/Ry, where V is the applied voltage.

  19. 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.

  20. 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.

  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. Effective switching frequency multiplier inverter

    DOEpatents

    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.

  3. 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.

  4. 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.

  5. Inverted annular flow experimental study

    SciTech Connect

    De Jarlais, G.; Ishii, M.

    1985-04-01

    Steady-state inverted annular flow of Freon 113 in up flow was established in a transparent test section. Using a special inlet configuration consisting of long aspect-ratio liquid nozzles coaxially centered within a heated quartz tube, idealized inverted annular flow initial geometry (cylindrical liquid core surrounded by coaxial annulus of gas) could be established. Inlet liquid and gas flowrates, liquid subcooling, and gas density (using various gas species) were measured and varied systematically. The hydrodynamic behavior of the liquid core, and the subsequent downstream break-up of this core into slugs, ligaments and/or droplets of various sizes, was observed. In general, for low inlet liquid velocities it was observed that after the initial formation of roll waves on the liquid core surface, an agitated region of high surface area, with attendant high momentum and energy transfers, occurs. This agitated region appears to propagate downsteam in a quasi-periodic pattern. Increased inlet liquid flow rates, and high gas annulus flow rates tend to diminish the significance of this agitated region. Observed inverted annular flow (and subsequent downstream flow pattern) hydrodynamic behavior is reported, and comparisons are drawn to data generated by previous experimenters studying post-CHF flow.

  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. 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.

  9. Inverted ductal papilloma of minor salivary glands.

    PubMed

    Hegarty, D J; Hopper, C; Speight, P M

    1994-08-01

    Inverted ductal papillomas are rare tumours of minor salivary glands. A case is reported on the lower lip of a 50-year-old man. The tumour showed a characteristic endophytic growth pattern and was composed of bulbous papillary projections of basaloid cells dilating and filling the superficial portion of the excretory duct. Histologically, inverted ductal papillomas resemble the inverted papilloma of the nose and paranasal sinuses, but are completely benign and are not associated with malignant change.

  10. Cascade Multilevel Inverters for Utility Applications

    SciTech Connect

    Peng, F.Z., McKeever, J.W., Adams, D.J.

    1997-12-31

    Cascade multilevel inverters have been developed by the authors for utility applications. A cascade M-level inverter consists of (M-1)/2 H- bridges in which each bridge has its own separate dc source. The new inverter: (1) can generate almost sinusoidal waveform voltage while only switching one time per fundamental cycle, (2) can eliminate transformers of multipulse inverters used in conventional utility interfaces and static var compensators, and (3) makes possible direct parallel or series connection to medium- and high-voltage power systems without any transformers. In other words, the cascade inverter is much more efficient and suitable for utility applications than traditional multipulse and pulse width modulation (PWM) inverters. The authors have experimentally demonstrated the superiority of the new inverter for reactive power (var) and harmonic compensation. This paper will summarize 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 demonstrate the superiority of the new inverters.

  11. Repeat-until-success quantum repeaters

    NASA Astrophysics Data System (ADS)

    Bruschi, David Edward; Barlow, Thomas M.; Razavi, Mohsen; Beige, Almut

    2014-09-01

    We propose a repeat-until-success protocol to improve the performance of probabilistic quantum repeaters. Conventionally, these rely on passive static linear-optics elements and photodetectors to perform Bell-state measurements (BSMs) with a maximum success rate of 50%. This is a strong impediment for entanglement swapping between distant quantum memories. Every time a BSM fails, entanglement needs to be redistributed between the corresponding memories in the repeater link. The key ingredients of our scheme are repeatable BSMs. Under ideal conditions, these turn probabilistic quantum repeaters into deterministic ones. Under realistic conditions, our protocol too might fail. However, using additional threshold detectors now allows us to improve the entanglement generation rate by almost orders of magnitude, at a nominal distance of 1000 km, compared to schemes that rely on conventional BSMs. This improvement is sufficient to make the performance of our scheme comparable to the expected performance of some deterministic quantum repeaters.

  12. 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

  13. 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.

  14. 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)

  15. 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.

  16. A Repeat Look at Repeating Patterns

    ERIC Educational Resources Information Center

    Markworth, Kimberly A.

    2016-01-01

    A "repeating pattern" is a cyclical repetition of an identifiable core. Children in the primary grades usually begin pattern work with fairly simple patterns, such as AB, ABC, or ABB patterns. The unique letters represent unique elements, whereas the sequence of letters represents the core that is repeated. Based on color, shape,…

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. Inverted organic electronic and optoelectronic devices

    NASA Astrophysics Data System (ADS)

    Small, Cephas E.

    The research and development of organic electronics for commercial application has received much attention due to the unique properties of organic semiconductors and the potential for low-cost high-throughput manufacturing. For improved large-scale processing compatibility and enhanced device stability, an inverted geometry has been employed for devices such as organic light emitting diodes and organic photovoltaic cells. These improvements are attributed to the added flexibility to incorporate more air-stable materials into the inverted device geometry. However, early work on organic electronic devices with an inverted geometry typically showed reduced device performance compared to devices with a conventional structure. In the case of organic light emitting diodes, inverted devices typically show high operating voltages due to insufficient carrier injection. Here, a method for enhancing hole injection in inverted organic electronic devices is presented. By incorporating an electron accepting interlayer into the inverted device, a substantial enhancement in hole injection efficiency was observed as compared to conventional devices. Through a detailed carrier injection study, it is determined that the injection efficiency enhancements in the inverted devices are due to enhanced charge transfer at the electron acceptor/organic semiconductor interface. A similar situation is observed for organic photovoltaic cells, in which devices with an inverted geometry show limited carrier extraction in early studies. In this work, enhanced carrier extraction is demonstrated for inverted polymer solar cells using a surface-modified ZnO-polymer composite electron-transporting layer. The insulating polymer in the composite layer inhibited aggregation of the ZnO nanoparticles, while the surface-modification of the composite interlayer improved the electronic coupling with the photoactive layer. As a result, inverted polymer solar cells with power conversion efficiencies of over 8

  2. 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.

  3. Invertible authentication for 3D meshes

    NASA Astrophysics Data System (ADS)

    Dittmann, Jana; Benedens, Oliver

    2003-06-01

    Digital watermarking has become an accepted technology for enabling multimedia protection schemes. Based on the introduced media independent protocol schemes for invertible data authentication in references 2, 4 and 5 we discuss the design of a new 3D invertible labeling technique to ensure and require high data integrity. We combine digital signature schemes and digital watermarking to provide a public verifiable integrity. Furthermore the protocol steps in the other papers to ensure that the original data can only be reproduced with a secret key is adopted for 3D meshes. The goal is to show how the existing protocol can be used for 3D meshes to provide solutions for authentication watermarking. In our design concept and evaluation we see that due to the nature of 3D meshes the invertible function are different from the image and audio concepts to achieve invertibility to guaranty reversibility of the original. Therefore we introduce a concept for distortion free invertibility and a concept for adjustable minimum distortion invertibility.

  4. Dynamic Inverted Quadtree: A Structure for Pictorial Databases.

    ERIC Educational Resources Information Center

    Vassilakopoulos, Michael; Manolopoulos, Yannis

    1995-01-01

    Presents an improved inverted region quadtree variation called Dynamic Inverted Quadtree that is able to support and index a pictorial database. Pattern-searching algorithms are described, and the space needs of Fully Inverted and Dynamic Inverted Quadtrees are analytically compared based on a model of image randomness expressed as a branching…

  5. 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

  6. Inverting sets and the packing problem

    SciTech Connect

    Faber, V.; Goldberg, M.K.; Knill, E.; Spencer, T.H.

    1992-12-01

    Given a set V, a subset S, and a permutation {pi} of V, we say that {pi} permutes S if {pi}(S) {intersection} S = {theta}. Given a collection S = (V; S{sub 1}..., S{sub m}), where S{sub i} {improper_subset} V (i = 1,...,m), we say that S is invertible if there is a permutation {pi} of V such that {pi}(S{sub i}) {improper_subset} V -- S{sub i}. In this paper, we present necessary and sufficient conditions for the invertibility of a collection and construct a polynomial algorithm which determines whether a given collection is invertible. For an arbitrary collection, we give a lower bound for the maximum number of sets that can be inverted. Finally, we consider the problem of constructing a collection of sets such that no sub-collection of size three is invertible. Our constructions of such collections come from solutions to the packing problem with unbounded block sizes. We prove several new lower and upper bounds for the packing problem and present a new explicit construction of packing.

  7. Inverting sets and the packing problem

    SciTech Connect

    Faber, V. ); Goldberg, M.K. . Dept. of Computer Science); Knill, E. . School of Computer Science); Spencer, T.H. . Dept. of Mathematics and Computer Science)

    1992-01-01

    Given a set V, a subset S, and a permutation [pi] of V, we say that [pi] permutes S if [pi](S) [intersection] S = [theta]. Given a collection S = (V; S[sub 1]..., S[sub m]), where S[sub i] [improper subset] V (i = 1,...,m), we say that S is invertible if there is a permutation [pi] of V such that [pi](S[sub i]) [improper subset] V -- S[sub i]. In this paper, we present necessary and sufficient conditions for the invertibility of a collection and construct a polynomial algorithm which determines whether a given collection is invertible. For an arbitrary collection, we give a lower bound for the maximum number of sets that can be inverted. Finally, we consider the problem of constructing a collection of sets such that no sub-collection of size three is invertible. Our constructions of such collections come from solutions to the packing problem with unbounded block sizes. We prove several new lower and upper bounds for the packing problem and present a new explicit construction of packing.

  8. Power inverter implementing phase skipping control

    DOEpatents

    Somani, Utsav; Amirahmadi, Ahmadreza; Jourdan, Charles; Batarseh, Issa

    2016-10-18

    A power inverter includes a DC/AC inverter having first, second and third phase circuitry coupled to receive power from a power source. A controller is coupled to a driver for each of the first, second and third phase circuitry (control input drivers). The controller includes an associated memory storing a phase skipping control algorithm, wherein the controller is coupled to receive updating information including a power level generated by the power source. The drivers are coupled to control inputs of the first, second and third phase circuitry, where the drivers are configured for receiving phase skipping control signals from the controller and outputting mode selection signals configured to dynamically select an operating mode for the DC/AC inverter from a Normal Control operation and a Phase Skipping Control operation which have different power injection patterns through the first, second and third phase circuitry depending upon the power level.

  9. 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.

  10. 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

  11. 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.

  12. 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

    2015-06-02

    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.

  13. Simplified space vector PWM algorithm for five-level inverter

    NASA Astrophysics Data System (ADS)

    Lalili, D.; Berkouk, E. M.; Boudjema, F.; Lourci, N.; Taleb, T.; Petzold, J.

    2007-12-01

    In this work, we present an algorithm for the space vector pulse width modulation (SVPWM) applied to five-level diode clamped inverter. In this algorithm, the space vector diagram of the five-level inverter is decomposed into six space vector diagrams of three-level inverters. In turn, each of these six space vector diagrams of three-level inverter is decomposed into six space vector diagrams of two-level inverters. This idea allows us to generalize the two-level SVPWM algorithm into the case of five-level inverter.

  14. 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.

  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. 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)

  18. 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.

  19. 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.

  20. 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)

  1. 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

  2. Tandem repeats and heteroplasmy in the mitochondrial DNA control region of the loggerhead shrike (Lanius ludovicianus).

    PubMed

    Mundy, N I; Winchell, C S; Woodruff, D S

    1996-01-01

    We report the presence of a 128 bp tandem repeat in the mitochondrial control region of the loggerhead shrike (Aves: Lanius ludovicianus). All individuals examined had either two or three copies of the repeat or were heteroplasmic for two and three copies. This is the first direct demonstration of a tandem repeat associated with heteroplasmy in the control region of a bird. A novel model for repeat duplication, which involves an inverted repeat located adjacent to the tandemly repeated sequence, is presented. Individuals with three repeats are absent from the endangered population of San Clemente loggerhead shrike in southern California, suggesting that the island endemic has a small effective population size and that there is insignificant gene flow from the adjacent mainland.

  3. 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…

  4. Primary and recurrent inverting papilloma: appearances with magnetic resonance imaging.

    PubMed

    Roobottom, C A; Jewell, F M; Kabala, J

    1995-07-01

    Inverting papilloma of the sinonasal cavity is of importance because of its association with squamous cell carcinoma and its tendency to local recurrence. Appearances of inverting papilloma have only been reported infrequently, and never in recurrent cases. We present the magnetic resonance imaging (MRI) appearances of four cases of inverting papilloma, three of which are recurrent.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Slit Wheel Repeatability

    NASA Astrophysics Data System (ADS)

    DiFelice, Audrey

    2012-10-01

    Test the repeatibility of the slit wheel by taking a sequence of comparison lamp spectra with grating G230MB {2697} and the three smallest long slits {52X0.2, 52X0.1, and 52X0.05}. This is a clone of Cycle 19 Program 12771.

  18. Slit Wheel Repeatability

    NASA Astrophysics Data System (ADS)

    Long, Chris

    2011-10-01

    Test the repeatibility of the slit wheel by taking a sequence of comparison lamp spectra with grating G230MB {2697} and the three smallest long slits {52X0.2, 52X0.1, and 52X0.05}. This is a clone of Cycle 18 Program 12410.

  19. Slit Wheel Repeatability

    NASA Astrophysics Data System (ADS)

    DiFelice, Audrey

    2013-10-01

    Test the repeatibility of the slit wheel by taking a sequence of comparison lamp spectra with grating G230MB {2697} and the three smallest long slits {52X0.2, 52X0.1, and 52X0.05}. This is a clone of Cycle 20 Program 13140.

  20. Slit Wheel Repeatability

    NASA Astrophysics Data System (ADS)

    Zheng, Wei

    2010-09-01

    Test the repeatibility of the slit wheel by taking a sequence of comparison lamp spectra with grating G230MB {2697} and the three smallest long slits {52X0.2, 52X0.1, and 52X0.05}. This is a clone of Cycle 17 Program 11851.

  1. 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…

  2. All-optical repeater.

    PubMed

    Silberberg, Y

    1986-06-01

    An all-optical device containing saturable gain, saturable loss, and unsaturable loss is shown to transform weak, distorted optical pulses into uniform standard-shape pulses. The proposed device performs thresholding, amplification, and pulse shaping as required from an optical repeater. It is shown that such a device could be realized by existing semiconductor technology.

  3. 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.

  4. Electrodynamics of AN Ion Inverted V.

    NASA Astrophysics Data System (ADS)

    Burgess, Georgette Olive

    Particle precipitation around the earth's polar regions may be the footprint of various energizing phenomena in the magnetosphere. Satellite-observed electron fluxes whose peak energy increases then decreases are called inverted V's. The Atmosphere Explorer-D Low Energy Electron (LEE) data for January 11, 1976 indicates that the precipitating ions have been accelerated. In this event the spectrograms of the ion flux shows the change of the peak energy with time characteristic of an inverted V. The electron population is decelerated as the ion population is accelerated, consistent with a downward electric field. The Birkeland current at an inverted V may be calculated in two ways: from the divergence of the electric field or from the observed particle fluxes. We found that the two methods agree on the location of Birkeland current throughout the event, but the magnitudes are not the same. This is not surprising, since the component of (DEL)((')(SIGMA)(.)(')E) perpendicular to the trajectory can not be determined. The electric potential along the spacecraft's trajectory (790-650 km altitude) was calculated from the measured electric fields. The sum of the parallel potential drop (inferred from the ion distribution function) and the ionospheric potential gives the potential profile at the magnetosphere. The parallel electric field thus partially decoupled the ionospheric flow from the magnetospheric flow. The electric field pattern in the magnetosphere -ionosphere system demands field-aligned currents. When the thermal current is insufficient, a field-aligned potential drop can accelerate particles to satisfy the requirements. The thermal electron current from the ionosphere is much greater than that from the magnetosphere. Thus, it is more common to observe the signatures of an upward electric field: the electron "inverted V". In the ion inverted V observed during AE-D orbit 1141, the postulated parallel potential has reduced the required parallel current. This high

  5. Complex telomere-associated repeat units in members of the genus Chironomus evolve from sequences similar to simple telomeric repeats.

    PubMed Central

    Nielsen, L; Edström, J E

    1993-01-01

    The dipteran Chironomus tentans has complex tandemly repeated 350-bp DNA sequences at or near the chromosome ends. As in Drosophila melanogaster, short simple repeats with cytosines and guanines in different strands have never been observed. We were therefore interested in learning whether the Chironomus repeats could have evolved from simple sequence telomeric DNA, which might suggest that they constitute a functional equivalent. We screened for repeat units with evolutionarily ancient features within the tandem arrays and recovered two clones with a less-evolved structure. Sequence analysis reveals that the present-day 350-bp unit probably evolved from a simpler 165-bp unit through the acquisition of transposed sequences. The 165-bp unit contains DNA with a highly biased distribution of cytosine and guanine between the two strands, although with the ratios inverted in two minor parts of the repeat. It is largely built up of short degenerate subrepeats for which most of the sequence can be reconstructed. The consensus for the subrepeat sequence is similar to the simple telomeric repeat sequences of several kinds of eukaryotes. We propose that the present-day unit has evolved from telomeric, simple sequence, asymmetric DNA from which it has retained some original sequence features and possibly functions. Images PMID:8441399

  6. Complex telomere-associated repeat units in members of the genus Chironomus evolve from sequences similar to simple telomeric repeats.

    PubMed

    Nielsen, L; Edström, J E

    1993-03-01

    The dipteran Chironomus tentans has complex tandemly repeated 350-bp DNA sequences at or near the chromosome ends. As in Drosophila melanogaster, short simple repeats with cytosines and guanines in different strands have never been observed. We were therefore interested in learning whether the Chironomus repeats could have evolved from simple sequence telomeric DNA, which might suggest that they constitute a functional equivalent. We screened for repeat units with evolutionarily ancient features within the tandem arrays and recovered two clones with a less-evolved structure. Sequence analysis reveals that the present-day 350-bp unit probably evolved from a simpler 165-bp unit through the acquisition of transposed sequences. The 165-bp unit contains DNA with a highly biased distribution of cytosine and guanine between the two strands, although with the ratios inverted in two minor parts of the repeat. It is largely built up of short degenerate subrepeats for which most of the sequence can be reconstructed. The consensus for the subrepeat sequence is similar to the simple telomeric repeat sequences of several kinds of eukaryotes. We propose that the present-day unit has evolved from telomeric, simple sequence, asymmetric DNA from which it has retained some original sequence features and possibly functions.

  7. 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.

  8. Genomic organization and developmental fate of adjacent repeated sequences in a foldback DNA clone of Tetrahymena thermophila

    SciTech Connect

    Tschunko, A.H.; Loechel, R.H.; McLaren, N.C.; Allen, S.L.

    1987-11-01

    DNA sequence elimination and rearrangement occurs during the development of somatic cell lineages of eukaryotes and was first discovered over a century ago. However, the significance and mechanism of chromatin elimination are not understood. DNA elimination also occurs during the development of the somatic macronucleus from the germinal micronucleus in unicellular ciliated protozoa such as Tetrahymena thermophila. In this study foldback DNA from the micronucleus was used as a probe to isolate ten clones. All of those tested (4/4) contained sequences that were repetitive in the micronucleus and rearranged in the macronucleus. Inverted repeated sequences were present in one clone. This clone, pTtFBl, was subjected to a detailed analysis of its developmental fate. Subregions were subcloned and used as probes against Southern blots of micronuclear and macronuclear DNA. DNA was labeled with (/sup 33/P)-labeled dATP. The authors found that all subregions defined repeated sequence families in the micronuclear genome. A minimum of four different families was defined, two of which are retained in the macronucleus and two of which are completely eliminated. The inverted repeat family is retained with little rearrangement. Two of the families, defined by subregions that do not contain parts of the inverted repeat are totally eliminated during macronuclear development-and contain open reading frames. The significance of retained inverted repeats to the process of elimination is discussed.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. On Inverting the Heat Flow with Engineering Materials

    NASA Astrophysics Data System (ADS)

    Zhou, Li

    2016-02-01

    Transformation thermodynamics enriches our understanding of heat flow and makes it possible to manipulate the heat flow at will, like shielding, concentrating and inverting. The inverting of heat flow is the extreme one, which has not been studied specifically yet. In this study we firstly inverted the heat flow by transformation thermodynamics and provided the formula for the transformed thermal conductivity. Finite element simulations were conducted to realize the steady and non-steady inverting of heat flow, based on the eccentric-semi-ring structures with natural materials. To do the inverting of heat flow, a simple "L"-shape conductive structure was proposed and verified with an infrared camera. It is concluded that inverting heat flow can be done by both complex engineering materials and some simple structures.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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).

  1. 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.

  2. 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.

  3. Towards high performance inverted polymer solar cells

    NASA Astrophysics Data System (ADS)

    Gong, Xiong

    2013-03-01

    Bulk heterojunction polymer solar cells that can be fabricated by solution processing techniques are under intense investigation in both academic institutions and industrial companies because of their potential to enable mass production of flexible and cost-effective alternative to silicon-based electronics. Despite the envisioned advantages and recent technology advances, so far the performance of polymer solar cells is still inferior to inorganic counterparts in terms of the efficiency and stability. There are many factors limiting the performance of polymer solar cells. Among them, the optical and electronic properties of materials in the active layer, device architecture and elimination of PEDOT:PSS are the most determining factors in the overall performance of polymer solar cells. In this presentation, I will present how we approach high performance of polymer solar cells. For example, by developing novel materials, fabrication polymer photovoltaic cells with an inverted device structure and elimination of PEDOT:PSS, we were able to observe over 8.4% power conversion efficiency from inverted polymer solar cells.

  4. 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.

  5. 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.

  6. 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

  7. Intrachromosomal homologous recombination between inverted amplicons on opposing Y-chromosome arms.

    PubMed

    Lange, Julian; Noordam, Michiel J; van Daalen, Saskia K M; Skaletsky, Helen; Clark, Brian A; Macville, Merryn V; Page, David C; Repping, Sjoerd

    2013-10-01

    Amplicons--large, nearly identical repeats in direct or inverted orientation--are abundant in the male-specific region of the human Y chromosome (MSY) and provide targets for intrachromosomal non-allelic homologous recombination (NAHR). Thus far, NAHR events resulting in deletions, duplications, inversions, or isodicentric chromosomes have been reported only for amplicon pairs located exclusively on the short arm (Yp) or the long arm (Yq). Here we report our finding of four men with Y chromosomes that evidently formed by intrachromosomal NAHR between inverted repeat pairs comprising one amplicon on Yp and one amplicon on Yq. In two men with spermatogenic failure, sister-chromatid crossing-over resulted in pseudoisoYp chromosome formation and loss of distal Yq. In two men with normal spermatogenesis, intrachromatid crossing-over generated pericentric inversions. These findings highlight the recombinogenic nature of the MSY, as intrachromosomal NAHR occurs for nearly all Y-chromosome amplicon pairs, even those located on opposing chromosome arms.

  8. 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…

  9. 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

  10. 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.

  11. Novel optoelectronic RS flipflop based on optically coupled inverters

    NASA Astrophysics Data System (ADS)

    Chino, T.; Matsuda, K.; Adachi, H.; Shibata, J.

    1992-03-01

    An optoelectronic RS flipflop emitting differential output has been proposed and demonstrated. It consists of two optical inverters. Optical interconnections are used to couple these inverters. Stable operation for the variation of bias voltage is demonstrated, which exhibits the possibility for 2-dimensional integration.

  12. Quasicompactons in inverted nonlinear photonic crystals

    SciTech Connect

    Li Yongyao; Malomed, Boris A.; Wu Jianxiong; Pang Wei; Wang Sicong; Zhou Jianying

    2011-10-15

    We study large-amplitude one-dimensional solitary waves in photonic crystals featuring competition between linear and nonlinear lattices, with minima of the linear potential coinciding with maxima of the nonlinear pseudopotential, and vice versa (inverted nonlinear photonic crystals, INPCs), in the case of the saturable self-focusing nonlinearity. Such crystals were recently fabricated using a mixture of SU-8 and Rhodamine-B optical materials. By means of numerical methods and analytical approximations, we find that large-amplitude solitons are broad sharply localized stable pulses (quasicompactons, QCs). With the increase of the total power, P, the QC's centroid performs multiple switchings between minima and maxima of the linear potential. Unlike cubic INPCs, the large-amplitude solitons are mobile in the medium with the saturable nonlinearity. The threshold value of the kick necessary to set the soliton in motion is found as a function of P. Collisions between moving QCs are considered too.

  13. 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.

  14. Scalar field cosmologies with inverted potentials

    SciTech Connect

    Boisseau, B.; Giacomini, H.

    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.

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. To Repeat or Not to Repeat a Course

    ERIC Educational Resources Information Center

    Armstrong, Michael J.; Biktimirov, Ernest N.

    2013-01-01

    The difficult transition from high school to university means that many students need to repeat (retake) 1 or more of their university courses. The authors examine the performance of students repeating first-year core courses in an undergraduate business program. They used data from university records for 116 students who took a total of 232…

  4. DWI Repeaters and Non-Repeaters: A Comparison.

    ERIC Educational Resources Information Center

    Weeber, Stan

    1981-01-01

    Discussed how driving-while-intoxicated (DWI) repeaters differed signigicantly from nonrepeaters on 4 of 23 variables tested. Repeaters were more likely to have zero or two dependent children, attend church frequently, drink occasionally and have one or more arrests for public intoxication. (Author)

  5. 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.

  6. 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.

  7. 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.

  8. Ru(II)-based metallosurfactant forming inverted aggregates.

    PubMed

    Domínguez-Gutiérrez, David; Surtchev, Marko; Eiser, Erika; Elsevier, Cornelis J

    2006-02-01

    Knowing the advantages of incorporating a transition metal into interfaces, we report on the first inverted aggregates formed using metallosurfactants. The metallosurfactant possesses four long linear tails that account for the shielding of the polar headgroup in apolar solvents. The nature of the so-formed aggregates changes dramatically from inverted vesicles (toluene) to inverted micelles (hexane). The size of the aggregates was determined using dynamic light scattering. Atomic force microscopy allowed us to study the dry structure of the vesicles on a glass surface.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. Repeated sequences in bacterial chromosomes and plasmids: a glimpse from sequenced genomes.

    PubMed

    Romero, D; Martínez-Salazar, J; Ortiz, E; Rodríguez, C; Valencia-Morales, E

    1999-01-01

    To gain insight into the extent of exact DNA repeats in sequenced bacterial genomes and their plasmids, we analyzed the collection of completely sequenced bacterial genomes available at GenBank using the program Miropeats. This program draws graphical representations of exact DNA repeats in whole genomes. In this work, we present maps showing the extent and type (inverted or direct) of exact DNA repeats longer than 300 bp for the whole collection. These repeats may participate in a variety of events relevant for bacterial genome plasticity, such as amplifications, deletions, inversions, and translocations (via homologous recombination), as well as transposition. Additionally, we review recent data showing that high-frequency architectural variations in genomic structure occur at both the interspecies and interstrain levels.

  14. Nifty Nines and Repeating Decimals

    ERIC Educational Resources Information Center

    Brown, Scott A.

    2016-01-01

    The traditional technique for converting repeating decimals to common fractions can be found in nearly every algebra textbook that has been published, as well as in many precalculus texts. However, students generally encounter repeating decimal numerals earlier than high school when they study rational numbers in prealgebra classes. Therefore, how…

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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

  20. 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

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 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

  7. 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

  8. Patterns of inverted reading and subgroups in dyslexia.

    PubMed

    Larsen, S; Parlenvi, P

    1984-01-01

    Reading performance of 46 poor readers was compared with that of 20 normal control readers. All subjects were second grade children. In Experiment 1 two matching word lists were presented under two conditions: one version of the test was read in the upright position and the other inverted. In Experiment 2 the eye movements of all subjects were recorded during reading of two meaningful sentences in the normal and inverted position. While the controls were negatively influenced by inversion of the text, the poor readers showed a variety of responses. Overall, the poor readers showed a slight tendency to be better at reading in the inverted position when the text must be scanned from right to left. An individual analysis of the data revealed that in 28.3% of the poor readers inverted reading improved performance at least 15 %, a phenomenon found in none of the controls.

  9. 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

  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. Multifocal inverted papillomas in the head and neck.

    PubMed

    Sharma, Jyoti; Goldenberg, David; Crist, Henry; McGinn, Johnathan

    2015-03-01

    Inverted papilloma is a rare benign neoplasm that usually originates in the lateral nasal wall. It can be a locally aggressive lesion and invade nearby structures. While primarily a nasal neoplasm, cases of an inverted papilloma involving the temporal bone, pharynx, nasopharynx, and lacrimal sac have been reported. We describe the case of a 67-year-old man with a history of nasal inverted papilloma who presented with a recurrent nasal mass and a large mass on the left side of his upper neck. The patient's history included inverted papillomas in multiple locations: the temporal bone, the sinonasal tract, and the nasopharynx. The new neck mass raised a concern for malignant degeneration and metastasis, but pathology demonstrated that it was a benign inverted papilloma. No clear etiology for the new neck lesion was evident except for an origin in salivary gland tissue. However, there was no physical connection between the neck mass and the submandibular gland identifiable on pathologic evaluation. This case illustrates the need for an aggressive primary resection to minimize local recurrence, as well as adequate surveillance to address recurrences early. Given the potential for multicentricity, patients with a typical sinonasal inverted papilloma should undergo a complete head and neck examination as part of their follow-up.

  12. 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

  13. GTAG- and CGTC-tagged palindromic DNA repeats in prokaryotes

    PubMed Central

    2013-01-01

    Background REPs (Repetitive Extragenic Palindromes) are small (20–40 bp) palindromic repeats found in high copies in some prokaryotic genomes, hypothesized to play a role in DNA supercoiling, transcription termination, mRNA stabilization. Results We have monitored a large number of REP elements in prokaryotic genomes, and found that most can be sorted into two large DNA super-families, as they feature at one end unpaired motifs fitting either the GTAG or the CGTC consensus. Tagged REPs have been identified in >80 species in 8 different phyla. GTAG and CGTC repeats reside predominantly in microorganisms of the gamma and alpha division of Proteobacteria, respectively. However, the identification of members of both super- families in deeper branching phyla such Cyanobacteria and Planctomycetes supports the notion that REPs are old components of the bacterial chromosome. On the basis of sequence content and overall structure, GTAG and CGTC repeats have been assigned to 24 and 4 families, respectively. Of these, some are species-specific, others reside in multiple species, and several organisms contain different REP types. In many families, most units are close to each other in opposite orientation, and may potentially fold into larger secondary structures. In different REP-rich genomes the repeats are predominantly located between unidirectionally and convergently transcribed ORFs. REPs are predominantly located downstream from coding regions, and many are plausibly transcribed and function as RNA elements. REPs located inside genes have been identified in several species. Many lie within replication and global genome repair genes. It has been hypothesized that GTAG REPs are miniature transposons mobilized by specific transposases known as RAYTs (REP associated tyrosine transposases). RAYT genes are flanked either by GTAG repeats or by long terminal inverted repeats (TIRs) unrelated to GTAG repeats. Moderately abundant families of TIRs have been identified in

  14. 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

  15. Protein Repeats from First Principles.

    PubMed

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

    2016-04-05

    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.

  16. 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

  17. 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.

  18. Pheochromocytoma-Induced Inverted Takotsubo-Like Cardiomyopathy Leading to Cardiogenic Shock Successfully Treated With Extracorporeal Membrane Oxygenation.

    PubMed

    Flam, Benjamin; Broomé, Michael; Frenckner, Björn; Bränström, Robert; Bell, Max

    2015-09-01

    Pheochromocytoma classically displays a variety of rather benign symptoms, such as headache, palpitations, and sweating, although severe cardiac manifestations have been described. We report a case of pheochromocytoma-induced inverted takotsubo-like cardiomyopathy leading to shock and cardiac arrest successfully treated with extracorporeal membrane oxygenation (ECMO) as a bridge to pharmacological therapy and curative adrenalectomy. A previously healthy 46-year-old woman presented to the emergency department with abdominal pain, dyspnea, nausea, and vomiting. Clinical evaluation revealed cardiorespiratory failure with hypoxia and severe metabolic acidosis. Computed tomography (CT) scan showed pulmonary edema and a left adrenal mass. Transthoracic echocardiography (TTE) displayed severe left ventricular dysfunction with inverted takotsubo contractile pattern. Despite mechanical ventilation and inotropic and vasopressor support, asystolic cardiac arrest ensued. The patient was resuscitated using manual chest compressions followed by venoarterial ECMO. Repeated TTEs demonstrated resolution of the cardiomyopathy within a few days. Laboratory results indicated transient renal and hepatic dysfunction, and CT scan of the brain displayed occipital infarctions. Biochemical testing and radionuclide scintigraphy confirmed a pheochromocytoma. Pharmacological adrenergic blockade was instituted prior to delayed adrenalectomy after which the diagnosis was histopathologically verified. The patient recovered after rehabilitation. We conclude that pheochromocytoma should be considered in patients presenting with unexplained cardiovascular compromise, especially if they display (inverted) takotsubo contractile pattern. Timely, adequate management might involve ECMO as a bridge to pharmacological therapy and curative surgery.

  19. Inverted Wedding Cake Growth Operated by the Ehrlich-Schwoebel Barrier in Two-Dimensional Nanocrystal Evolution.

    PubMed

    Yin, Xin; Geng, Dalong; Wang, Xudong

    2016-02-01

    Wedding cake growth is a layer-by-layer growth model commonly observed in epitaxial growth of metal films, featured by repeated nucleation of new atomic layers on the topmost surface owing to the confinement of the Ehrlich-Schwoebel (ES) barrier. Herein, we report an inverted wedding cake growth phenomenon observed in two-dimensional nanostructure evolution. Through a dynamically controlled vapor-solid deposition process of ZnO, a unique basin-shaped crown was formed on the tip of each nanowire, featured with concentric steps. The atomic steps were nucleated along the edge and propagated toward the center. This is an opposite growth behavior compared to the conventional wedding cake growth, and is thus denoted as inverted wedding cake growth. Through the relation between the crown expansion rate and the temperature, the ES barrier of ZnO was determined to be 0.88 eV. The discovery of inverted wedding cake growth provided insight into the developing nanostructure growth mechanisms.

  20. The Rhodomonas salina mitochondrial genome: bacteria-like operons, compact gene arrangement and complex repeat region.

    PubMed

    Hauth, Amy M; Maier, Uwe G; Lang, B Franz; Burger, Gertraud

    2005-01-01

    To gain insight into the mitochondrial genome structure and gene content of a putatively ancestral group of eukaryotes, the cryptophytes, we sequenced the complete mitochondrial DNA of Rhodomonas salina. The 48 063 bp circular-mapping molecule codes for 2 rRNAs, 27 tRNAs and 40 proteins including 23 components of oxidative phosphorylation, 15 ribosomal proteins and two subunits of tat translocase. One potential protein (ORF161) is without assigned function. Only two introns occur in the genome; both are present within cox1 belong to group II and contain RT open reading frames. Primitive genome features include bacteria-like rRNAs and tRNAs, ribosomal protein genes organized in large clusters resembling bacterial operons and the presence of the otherwise rare genes such as rps1 and tatA. The highly compact gene organization contrasts with the presence of a 4.7 kb long, repeat-containing intergenic region. Repeat motifs approximately 40-700 bp long occur up to 31 times, forming a complex repeat structure. Tandem repeats are the major arrangement but the region also includes a large, approximately 3 kb, inverted repeat and several potentially stable approximately 40-80 bp long hairpin structures. We provide evidence that the large repeat region is involved in replication and transcription initiation, predict a promoter motif that occurs in three locations and discuss two likely scenarios of how this highly structured repeat region might have evolved.

  1. Isolation and characterization of a variant of human papillomavirus type 11 from a nasal inverting (Schneiderian) papilloma.

    PubMed

    Pater, A; Gardner, H; Respler, D S; Jahn, A; Pater, M M

    1988-06-01

    We have previously reported the presence of a variant of human papillomavirus (HPV) type 11 in a nasal inverting papilloma [Respler et al., 1987]. In the present study, we have cloned molecularly the DNA of this variant at its unique restriction enzyme Bam HI site into lambda BF101 phage. Restriction enzyme mapping and DNA sequencing revealed that the genome of this virus contained an extra 531 base pair (bp) which was the repeat of most of the noncoding region (ncr) of HPV 11. Insertion of transcriptional control elements, including the repeated sequence, in front of the chloramphenicol acetyltransferase (CAT) gene resulted in a 5- to 30-fold increase in expression in transfected cells, as compared to the constructs containing a single ncr of HPV 11. This increased expression was due to enhanced levels of CAT RNA the synthesis of which is initiated by the viral promoter element. PMID:2839608

  2. 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.

  3. 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

  4. Factorization method and new potentials from the inverted oscillator

    SciTech Connect

    Bermudez, David Fernández C, David J.

    2013-06-15

    In this article we will apply the first- and second-order supersymmetric quantum mechanics to obtain new exactly-solvable real potentials departing from the inverted oscillator potential. This system has some special properties; in particular, only very specific second-order transformations produce non-singular real potentials. It will be shown that these transformations turn out to be the so-called complex ones. Moreover, we will study the factorization method applied to the inverted oscillator and the algebraic structure of the new Hamiltonians. -- Highlights: •We apply supersymmetric quantum mechanics to the inverted oscillator potential. •The complex second-order transformations allow us to build new non-singular potentials. •The algebraic structure of the initial and final potentials is analyzed. •The initial potential is described by a complex-deformed Heisenberg–Weyl algebra. •The final potentials are described by polynomial Heisenberg algebras.

  5. Endoscopic transnasal management of inverted papilloma involving frontal sinuses

    PubMed Central

    Krzeski, Antoni; Held-Ziółkowska, Marta; Niemczyk, Kazimierz

    2012-01-01

    Inverted papilloma is a benign locally aggressive tumor of paranasal sinuses which has been traditionally managed with external surgical approaches. Advances in tumor imaging, surgical instrumentation and intraoperative visualization have led to a gradual shift to endonasal attachment-oriented surgery. Involvement of both frontal sinuses by inverted papilloma is rare. There are scant reports in the literature regarding this topic. We present 2 cases of the tumor involving both frontal sinuses removed by median drainage (Draf III procedure) under endoscopic guidance without any additional external approach. The whole cavity of both frontal sinuses was easily inspected at the end of the procedure. No early or late complications were observed. No recurrence was seen in 1-year or 2-year follow-up. Management of frontal sinus inverted papilloma with the endoscopic median drainage approach is feasible and seems to be effective. PMID:23362431

  6. 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.

  7. 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.

  8. Limitations on quantum key repeaters.

    PubMed

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

    2015-04-23

    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.

  9. 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

  10. 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.

  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. Optical-Mechanical System for Stabilizing an Inverted Pendulum

    NASA Astrophysics Data System (ADS)

    Kuzyakov, O. N.; Andreeva, M. A.

    2016-08-01

    Controlling open-loop unstable systems is a common benchmark for designing the algorithms to maintain the equilibrium state of anthropomorphous technical devices used within control theory. In this connection, considerable attention is currently being focused on the problem of stabilizing the inverted pendulum system. In this work, the execution of swinging-up the pendulum and, subsequently, maintaining its upward equilibrium state is presented with the help of the laboratory bench TP-802 by Festo Didactics and the movement control device. The configuration of dynamic system for stabilizing the inverted pendulum is offered. The algorithms to swing-up the pendulum and balance it around its upright position are offered as well.

  13. 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

  14. ZCS High Frequency Inverter for Aluminum Vessel Induction Heating

    NASA Astrophysics Data System (ADS)

    Ogiwara, Hiroyuki; Nakaoka, Mutsuo

    Recent induction cooking apparatus are utilized for induction heating of ferromagnetic materials at 20-50kHz with a high efficiency. They can not, however, be applied for non-magnetic materials such as aluminum vessels. Here, we present a voltage-clamp reverse conducting ZCS high frequency inverter of half bridge type for induction heating of an aluminum vessel. The switching devices utilized for this inverter are SITs and its operating frequency is determined as 200kHz. This paper describes its circuit constitution and the obtained experimental results from a practical point of view.

  15. Testing of a single cell cylindrical inverted converter

    NASA Astrophysics Data System (ADS)

    Desplat, Jean-Louis

    2002-01-01

    A Cylindrical Inverted Converter (CIC), made by Lutch, with the emitter on the outside was tested in a vacuum furnace supplying radiant heat to the emitter outer surface. The collector, coaxial with the emitter, has an integral heat pipe with sodium as the working fluid, which carries the heat dissipated in the collector to a radiating area with a coating of alumina and sub-stoichiometric TiO2. The CIC is a proof-of-principle device which will lead to the development of multi-cell inverted converter assemblies for space solar power systems. The thermionic performance at emitter temperatures of 1800 and 1900 K is presented. .

  16. 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.

  17. Non-invertible transformations of differential–difference equations

    NASA Astrophysics Data System (ADS)

    Garifullin, R. N.; Yamilov, R. I.; Levi, D.

    2016-09-01

    We discuss aspects of the theory of non-invertible transformations of differential–difference equations and, in particular, the notion of Miura type transformation. We introduce the concept of non-Miura type linearizable transformation and we present techniques that allow one to construct simple linearizable transformations and might help one to solve classification problems. This theory is illustrated by the example of a new integrable differential–difference equation depending on five lattice points, interesting from the viewpoint of the non-invertible transformation, which relate it to an Itoh–Narita–Bogoyavlensky equation.

  18. 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.

  19. 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

  20. 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…

  1. 78 FR 65594 - Vehicular Repeaters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-01

    ... mobile repeaters by public safety licensees on certain frequencies in the VHF band. DATES: Submit..., CART, etc.) by email: FCC504@fcc.gov or phone: 202-418- 0530 or TTY: 202-418-0432. For detailed... Proceedings, 63 FR 24121 (May 1, 1998). Electronic Filers: Comments may be filed electronically using...

  2. Repeat Pregnancies among Adolescent Mothers.

    ERIC Educational Resources Information Center

    Gillmore, Mary Rogers; Lewis, Steven M.; Lohr, Mary Jane; Spencer, Michael S.; White, Rachelle D.

    1997-01-01

    Reports the results of an event history analysis of rapidly repeated pregnancies among a sample of 170 adolescents. Results show that the best fitting model for these girls included two proximate determinants of pregnancy, contraceptive use, and other factors. Findings indicate that such pregnancies among teenagers are somewhat predictable. (RJM)

  3. 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

  4. Mobile inverted-repeat elements of the Tourist family are associated with the genes of many cereal grasses.

    PubMed Central

    Bureau, T E; Wessler, S R

    1994-01-01

    Tourist was originally described as a 128-bp insertion mutation in the maize wx-B2 allele. Subsequent analysis revealed that Tourist elements are in the introns or flanking sequences of 11 maize genes and a single barley gene. In this study we report that Tourist elements are frequently associated with the wild-type genes of two other grasses, rice and sorghum. Six of 35 rice and 5 of 8 sorghum complete gene sequences reported to date contain Tourist elements. Furthermore, 11 additional maize genes have been found to contain Tourist elements, bringing the current total of elements associated with maize genes to 23. Sequence comparison of Tourist elements has led to the identification of four subfamilies, designated A-D. Evidence is presented for the recent mobility of elements in three of these subfamilies and in three of the four grass species. These data suggest that Tourist elements are highly repetitive in the genomes of some and perhaps all members of the grasses. Images PMID:8108422

  5. Mobile inverted-repeat elements of the Tourist family are associated with the genes of many cereal grasses.

    PubMed

    Bureau, T E; Wessler, S R

    1994-02-15

    Tourist was originally described as a 128-bp insertion mutation in the maize wx-B2 allele. Subsequent analysis revealed that Tourist elements are in the introns or flanking sequences of 11 maize genes and a single barley gene. In this study we report that Tourist elements are frequently associated with the wild-type genes of two other grasses, rice and sorghum. Six of 35 rice and 5 of 8 sorghum complete gene sequences reported to date contain Tourist elements. Furthermore, 11 additional maize genes have been found to contain Tourist elements, bringing the current total of elements associated with maize genes to 23. Sequence comparison of Tourist elements has led to the identification of four subfamilies, designated A-D. Evidence is presented for the recent mobility of elements in three of these subfamilies and in three of the four grass species. These data suggest that Tourist elements are highly repetitive in the genomes of some and perhaps all members of the grasses.

  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. Canine inverted papillomas associated with DNA of four different papillomaviruses.

    PubMed

    Lange, Christian E; Tobler, Kurt; Brandes, Kristin; Breithardt, Kristin; Ordeix, Laura; Von Bomhard, Wolfgang; Favrot, Claude

    2010-06-01

    Inverted papillomas are uncommon papillomavirus (PV)-induced canine skin lesions. They consist of cup- to dome-shaped dermal nodules with a central pore filled with keratin. Histologically they are characterized by endophytic projections of the epidermis extending into dermis. Cytopathic effects of PVs infection include the presence of clumped keratohyalin granules, koilocytes and intranuclear inclusion bodies. Different DNA hybridization studies carried out with a canine oral papillomavirus (COPV) probe suggested that a different PV than COPV might cause these lesions. Canine papillomavirus 2 (CPV2) was discovered a few years ago in inverted papillomas of immunosuppressed beagles. Two other cases, presenting with distinct clinical and histological features have also been described. This study was carried out on four dogs with clinical and histological signs of inverted papillomas. Molecular biological analyses confirmed that PV DNA was present in all four lesions but demonstrated that the sequences in each case were different. One corresponded to COPV, the second to CPV2, and the third and fourth to unknown PVs. These findings suggest that inverted papillomas are not caused by one single PV type. Similar observations have also been made in human medicine. PMID:20042038

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  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. 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.

  16. 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.

  17. Polyomavirus large T antigen binds symmetrical repeats at the viral origin in an asymmetrical manner.

    PubMed

    Harrison, Celia; Jiang, Tao; Banerjee, Pubali; Meinke, Gretchen; D'Abramo, Claudia M; Schaffhausen, Brian; Bohm, Andrew

    2013-12-01

    Polyomaviruses have repeating sequences at their origins of replication that bind the origin-binding domain of virus-encoded large T antigen. In murine polyomavirus, the central region of the origin contains four copies (P1 to P4) of the sequence G(A/G)GGC. They are arranged as a pair of inverted repeats with a 2-bp overlap between the repeats at the center. In contrast to simian virus 40 (SV40), where the repeats are nonoverlapping and all four repeats can be simultaneously occupied, the crystal structure of the four central murine polyomavirus sequence repeats in complex with the polyomavirus origin-binding domain reveals that only three of the four repeats (P1, P2, and P4) are occupied. Isothermal titration calorimetry confirms that the stoichiometry is the same in solution as in the crystal structure. Consistent with these results, mutation of the third repeat has little effect on DNA replication in vivo. Thus, the apparent 2-fold symmetry within the DNA repeats is not carried over to the protein-DNA complex. Flanking sequences, such as the AT-rich region, are known to be important for DNA replication. When the orientation of the central region was reversed with respect to these flanking regions, the origin was still able to replicate and the P3 sequence (now located at the P2 position with respect to the flanking regions) was again dispensable. This highlights the critical importance of the precise sequence of the region containing the pentamers in replication.

  18. 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.

  19. Directionality switchable gain stabilized linear repeater

    NASA Astrophysics Data System (ADS)

    Ota, Takayuki; Ohmachi, Tadashi; Aida, Kazuo

    2004-10-01

    We propose a new approach to realize a bidirectional linear repeater suitable for future optical internet networks and fault location in repeater chain with OTDR. The proposed approach is the linear repeater of simple configuration whose directionality is rearranged dynamically by electrical control signal. The repeater is composed of a magneto-optical switch, a circulator, a dynamically gain stabilized unidirectional EDFA, and control circuits. The repeater directionality is rearranged as fast as 0.1ms by an electrical control pulse. It is experimentally confirmed that OTDR with the directionality switchable repeater is feasible for repeater chain. The detailed design and performance of the repeater are also discussed, including the multi-pass interference (MPI) which may arise in the proposed repeater, the effect of the MPI on SNR degradation of the repeater chain and the feed-forward EDFA gain control circuit.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. Stabilization and tracking control of X-Z inverted pendulum with sliding-mode control.

    PubMed

    Wang, Jia-Jun

    2012-11-01

    X-Z inverted pendulum is a new kind of inverted pendulum which can move with the combination of the vertical and horizontal forces. Through a new transformation, the X-Z inverted pendulum is decomposed into three simple models. Based on the simple models, sliding-mode control is applied to stabilization and tracking control of the inverted pendulum. The performance of the sliding mode control is compared with that of the PID control. Simulation results show that the design scheme of sliding-mode control is effective for the stabilization and tracking control of the X-Z inverted pendulum.

  12. 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

  13. Pheochromocytoma as a rare hidden cause of inverted stress cardiomyopathy.

    PubMed

    Cho, Soo Kyung; Kim, Kye Hun; Cho, Jae Yeong; Yoon, Hyun Ju; Park, Hyung Wook; Hong, Young Joon; Kim, Ju Han; Ahn, Youngkeun; Jeong, Myung Ho; Cho, Jeong Gwan; Park, Jong Chun

    2014-06-01

    Stress cardiomyopathy (SCMP) is characterized by a transient left ventricular dysfunction associated with apical ballooning and compensatory hyperkinesias of the basal segments after emotional or physical stress, but inverted or mid-ventricular variants of SCMP have also been described. Although catecholamine excess has been suggested as a possible pathophysiologic mechanism of SCMP, the etiology of SCMP is still unknown. Here, we report a case of inverted type of SCMP with clinical presentation mimicking acute coronary syndromes. The cause or precipitating stressor was unclear initially, but pheochromocytoma has been demonstrated as a cause of SCMP during clinical follow-up at out-patient clinic in the present case. Catecholamine-producing tumors should be included in the evaluation or management of SCMP, even though initial clinical manifestations are not suggestive for pheochromocytoma.

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

    DOE PAGES

    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

  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. Hybrid zero-voltage switching (ZVS) control for power inverters

    DOEpatents

    Amirahmadi, Ahmadreza; Hu, Haibing; Batarseh, Issa

    2016-11-01

    A power inverter combination includes a half-bridge power inverter including first and second semiconductor power switches receiving input power having an intermediate node therebetween providing an inductor current through an inductor. A controller includes input comparison circuitry receiving the inductor current having outputs coupled to first inputs of pulse width modulation (PWM) generation circuitry, and a predictive control block having an output coupled to second inputs of the PWM generation circuitry. The predictive control block is coupled to receive a measure of Vin and an output voltage at a grid connection point. A memory stores a current control algorithm configured for resetting a PWM period for a switching signal applied to control nodes of the first and second power switch whenever the inductor current reaches a predetermined upper limit or a predetermined lower limit.

  17. 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

  18. 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).

  19. 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.

  20. 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.

  1. 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.

  2. A molybdenum disulfide/carbon nanotube heterogeneous complementary inverter

    NASA Astrophysics Data System (ADS)

    Huang, Jun; Somu, Sivasubramanian; Busnaina, Ahmed

    2012-08-01

    We report a simple, bottom-up/top-down approach for integrating drastically different nanoscale building blocks to form a heterogeneous complementary inverter circuit based on layered molybdenum disulfide and carbon nanotube (CNT) bundles. The fabricated CNT/MoS2 inverter is composed of n-type molybdenum disulfide (MOS2) and p-type CNT transistors, with a high voltage gain of 1.3. The CNT channels are fabricated using directed assembly while the layered molybdenum disulfide channels are fabricated by mechanical exfoliation. This bottom-up fabrication approach for integrating various nanoscale elements with unique characteristics provides an alternative cost-effective methodology to complementary metal-oxide-semiconductors, laying the foundation for the realization of high performance logic circuits.

  3. A molybdenum disulfide/carbon nanotube heterogeneous complementary inverter.

    PubMed

    Huang, Jun; Somu, Sivasubramanian; Busnaina, Ahmed

    2012-08-24

    We report a simple, bottom-up/top-down approach for integrating drastically different nanoscale building blocks to form a heterogeneous complementary inverter circuit based on layered molybdenum disulfide and carbon nanotube (CNT) bundles. The fabricated CNT/MoS(2) inverter is composed of n-type molybdenum disulfide (MOS(2)) and p-type CNT transistors, with a high voltage gain of 1.3. The CNT channels are fabricated using directed assembly while the layered molybdenum disulfide channels are fabricated by mechanical exfoliation. This bottom-up fabrication approach for integrating various nanoscale elements with unique characteristics provides an alternative cost-effective methodology to complementary metal-oxide-semiconductors, laying the foundation for the realization of high performance logic circuits.

  4. Modeling and control of a pneumatically actuated inverted pendulum.

    PubMed

    Zilić, Tihomir; Pavković, Danijel; Zorc, Davor

    2009-07-01

    This paper presents the results of modeling of an inverted pendulum system driven by a linear pneumatic motor and equipped with relatively low-cost potentiometer-based position measurement system. Based on the nonlinear model of the overall pendulum system, which also includes notable friction effects, a linearized model is derived. The linearized model is used as a basis for the design of state feedback controller based on LQ and LQG optimization procedures. The linear state feedback controllers are augmented by a compensator of nonlinear friction effects whose design is based on the results of experimental identification of an appropriate static friction model. The proposed pendulum controller structures have been verified by means of computer simulations and experimentally on the experimental setup of a pneumatically actuated inverted pendulum.

  5. 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

  6. 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

  7. 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.

  8. 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

  9. [Somatic hypermutagenesis in immunoglobulin genes. I. Connection of somatic mutations with repeats. A statistical weighting method].

    PubMed

    Solov'ev, V V; Rogozin, I V; Kolchanov, N A

    1989-01-01

    Based on the analysis of a number of immunoglobulin genes' nucleotide sequences, it has been suggested, that somatic mutations emerge by means of imperfect duplexes correction, formed by mispairing of complementary regions of direct and inverted repeats. In the present work provides new data, confirming this mechanism of somatic hypermutagenesis. It has been shown that the presented sample of V- and J-segments of immunoglobulin genes is abundant in nonrandom imperfect direct repeats and complementary palindromes. To prove the connection of somatic mutations with the correction of imperfect duplexes, made up by the regions of these repeats, we have developed the method of statistical weights, permitting us to analyse the samples of mutations and repeats and to reveal the reliability of the connection between them. Using this method we have investigated the collection of 203 nucleotide substitutions in V- and J-segments and have shown a statistically reliable (P less than 10(-4) connection of these mutation positions with imperfect repeats.

  10. 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.

  11. 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.

  12. 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

  13. "Inverted" Solvent Effect on Charge Transfer in the Excited State.

    PubMed

    Nau; Pischel

    1999-10-01

    Faster in cyclohexane than in acetonitrile is the fluorescence quenching of the azoalkane 2,3-diazabicyclo[2.2.2]oct-2-ene (DBO) by amines and sulfides. Although this photoreaction is induced by charge transfer (CT; see picture) and exciplexes are formed, the increase in the dipole moment of the exciplex is not large enough to offset the solvent stabilization of the excited reactants, and an "inverted" solvent effect results.

  14. 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.

  15. 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

  16. Towards high performance inverted polymer solar cells through interfacial reengineering

    NASA Astrophysics Data System (ADS)

    Gong, Xiong

    2013-10-01

    Bulk heterojunction (BHJ) polymer solar cells (PSCs) that can be fabricated by solution processing techniques are under intense investigation in both academic institutions and industrial companies because of their potential to enable mass production of flexible and cost-effective alternative to silicon-based solar cells. A combination of novel polymer development, nanoscale morphology control and processing optimization has led to over 8% of power conversion efficiencies (PCEs) for BHJ PSCs with a conventional device structure. Attempts to develop PSCs with an inverted device structure as required for achieving high PECs and good stability have, however, met with limited success. Here, we report that (1) solution-processed zinc oxide (ZnO) thin film as an electron extraction layer for inverted polymer solar cells. Operated at room temperature, no obviously degradation was observed from the PSCs with ZnO layer after continuously illuminating the devices for 4 hours. However, a significantly degradation was observed from the PSCs without ZnO buffer layer after illuminating the devices only for 1 hour. Furthermore, PSCs with ZnO buffer layer also show very good shelf stability; only 10 % degradation observed in PCEs after 6 months; (2) a high PCE of 8.4% under AM1.5G irradiation was achieved for BHJ PSCs with an inverted device structure. This high efficiency was obtained through interfacial engineering of solution-processed electron extraction layer, ZnO, leading to facilitate electron transport and suppress bimolecular recombination. All these results provided an important progress for solution-processed PSCs, and demonstrated that PSCs with an inverted device structure are comparable with PSCs with the conventional device structure.

  17. Denture hyperplasia with areas simulating oral inverted ductal papilloma.

    PubMed

    Vargas, Pablo Agustin; Perez, Danyel Elias da Cruz; Jorge, Jacks; Rangel, Ana Lúcia Carrinho Ayrosa; León, Jorge Esquiche; Almeida, Oslei Paes de

    2005-07-01

    Denture hyperplasia is a reactive lesion of the oral mucosa, usually associated to an ill-fitting denture. This lesion is easily diagnosed and in some cases distinct microscopic variations such as osseous, oncocytic and squamous metaplasia may be found. These metaplastic alterations probably are associated with the lymphocytic infiltrate usually present in denture hyperplasia. We present a case of denture hyperplasia containing salivary gland tissue with ductal alterations mimicking an oral inverted ductal papilloma.

  18. 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.

  19. A state observer for the Virgo inverted pendulum.

    PubMed

    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; Di Paolo Emilio, M; Di Virgilio, A; Dietz, A; Drago, M; Endroczi, 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. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Decentralized Optimal Dispatch of Photovoltaic Inverters in Residential Distribution Systems

    SciTech Connect

    Dall'Anese, Emiliano; Dhople, Sairaj V.; Johnson, Brian B.; Giannakis, Georgios B.

    2015-10-05

    Summary form only given. Decentralized methods for computing optimal real and reactive power setpoints for residential photovoltaic (PV) inverters are developed in this paper. It is known that conventional PV inverter controllers, which are designed to extract maximum power at unity power factor, cannot address secondary performance objectives such as voltage regulation and network loss minimization. Optimal power flow techniques can be utilized to select which inverters will provide ancillary services, and to compute their optimal real and reactive power setpoints according to well-defined performance criteria and economic objectives. Leveraging advances in sparsity-promoting regularization techniques and semidefinite relaxation, this paper shows how such problems can be solved with reduced computational burden and optimality guarantees. To enable large-scale implementation, a novel algorithmic framework is introduced - based on the so-called alternating direction method of multipliers - by which optimal power flow-type problems in this setting can be systematically decomposed into sub-problems that can be solved in a decentralized fashion by the utility and customer-owned PV systems with limited exchanges of information. Since the computational burden is shared among multiple devices and the requirement of all-to-all communication can be circumvented, the proposed optimization approach scales favorably to large distribution networks.

  5. 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.

  6. 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.

  7. Urothelial carcinoma with an inverted growth pattern can be distinguished from inverted papilloma by fluorescence in situ hybridization, immunohistochemistry, and morphologic analysis.

    PubMed

    Jones, Timothy D; Zhang, Shaobo; Lopez-Beltran, Antonio; Eble, John N; Sung, Ming-Tse; MacLennan, Gregory T; Montironi, Rodolfo; Tan, Puay-Hoon; Zheng, Suqin; Baldridge, Lee Ann; Cheng, Liang

    2007-12-01

    Inverted papilloma of the urinary bladder and urothelial carcinoma with an inverted (endophytic) growth pattern may be difficult to distinguish histologically, especially in small biopsies. The distinction is important as these lesions have very different biologic behaviors and are treated differently. We examined histologic features and undertook immunohistochemical staining and UroVysion fluorescence in situ hybridization (FISH) to determine whether these methods could aid in making this distinction. We examined histologic sections from 15 inverted papillomas and 29 urothelial carcinomas with an inverted growth pattern. Each tumor was stained with antibodies to Ki-67, p53, and cytokeratin 20. In addition, each tumor was examined with UroVysion FISH for gains of chromosomes 3, 7, and 17 and for loss of chromosome 9p21 signals. None of the inverted papillomas stained positively for Ki-67 or for cytokeratin 20. Only 1 of 15 inverted papillomas stained positively for p53. By contrast, 66%, 59%, and 59% of urothelial carcinomas with an inverted growth pattern stained positively for Ki-67, p53, and cytokeratin 20, respectively. Only 3 of the urothelial carcinomas stained negatively for all 3 immunohistochemical markers. UroVysion FISH produced normal results for all cases of inverted papilloma. By contrast, 21 of 29 cases (72%) of urothelial carcinoma with an inverted growth pattern demonstrated chromosomal abnormalities typical of urothelial cancer and were considered positive by UroVysion FISH criteria. Morphologic features, as well as immunohistochemical stains (including stains for Ki-67, p53, and cytokeratin 20) and/or UroVysion FISH can help to distinguish inverted papilloma from urothelial carcinoma with an inverted growth pattern. PMID:18043040

  8. 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

  9. Crowding by a repeating pattern.

    PubMed

    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.

  10. Test Protocols for Advanced Inverter Interoperability Functions - Appendices

    SciTech Connect

    Johnson, Jay Dean; Gonzalez, Sigifredo; Ralph, Mark E.; Ellis, Abraham; Broderick, Robert Joseph

    2013-11-01

    Distributed energy resources (DER) such as photovoltaic (PV) systems, when deployed in a large scale, are capable of influencing significantly the operation of power systems. Looking to the future, stakeholders are working on standards to make it possible to manage the potentially complex interactions between DER and the power system. In 2009, the Electric Power Research Institute (EPRI), Sandia National Laboratories (SNL) with the U.S. Department of Energy (DOE), and the Solar Electric Power Association (SEPA) initiated a large industry collaborative to identify and standardize definitions for a set of DER grid support functions. While the initial effort concentrated on grid-tied PV inverters and energy storage systems, the concepts have applicability to all DER. A partial product of this on-going effort is a reference definitions document (IEC TR 61850-90-7, Object models for power converters in distributed energy resources (DER) systems) that has become a basis for expansion of related International Electrotechnical Commission (IEC) standards, and is supported by US National Institute of Standards and Technology (NIST) Smart Grid Interoperability Panel (SGIP). Some industry-led organizations advancing communications protocols have also embraced this work. As standards continue to evolve, it is necessary to develop test protocols to independently verify that the inverters are properly executing the advanced functions. Interoperability is assured by establishing common definitions for the functions and a method to test compliance with operational requirements. This document describes test protocols developed by SNL to evaluate the electrical performance and operational capabilities of PV inverters and energy storage, as described in IEC TR 61850-90-7. While many of these functions are not now required by existing grid codes or may not be widely available commercially, the industry is rapidly moving in that direction. Interoperability issues are already apparent as

  11. Test Protocols for Advanced Inverter Interoperability Functions – Main Document

    SciTech Connect

    Johnson, Jay Dean; Gonzalez, Sigifredo; Ralph, Mark E.; Ellis, Abraham; Broderick, Robert Joseph

    2013-11-01

    Distributed energy resources (DER) such as photovoltaic (PV) systems, when deployed in a large scale, are capable of influencing significantly the operation of power systems. Looking to the future, stakeholders are working on standards to make it possible to manage the potentially complex interactions between DER and the power system. In 2009, the Electric Power Research Institute (EPRI), Sandia National Laboratories (SNL) with the U.S. Department of Energy (DOE), and the Solar Electric Power Association (SEPA) initiated a large industry collaborative to identify and standardize definitions for a set of DER grid support functions. While the initial effort concentrated on grid-tied PV inverters and energy storage systems, the concepts have applicability to all DER. A partial product of this on-going effort is a reference definitions document (IEC TR 61850-90-7, Object models for power converters in distributed energy resources (DER) systems) that has become a basis for expansion of related International Electrotechnical Commission (IEC) standards, and is supported by US National Institute of Standards and Technology (NIST) Smart Grid Interoperability Panel (SGIP). Some industry-led organizations advancing communications protocols have also embraced this work. As standards continue to evolve, it is necessary to develop test protocols to independently verify that the inverters are properly executing the advanced functions. Interoperability is assured by establishing common definitions for the functions and a method to test compliance with operational requirements. This document describes test protocols developed by SNL to evaluate the electrical performance and operational capabilities of PV inverters and energy storage, as described in IEC TR 61850-90-7. While many of these functions are not currently required by existing grid codes or may not be widely available commercially, the industry is rapidly moving in that direction. Interoperability issues are already

  12. 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…

  13. 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... Offshore Radiotelephone Service § 22.1015 Repeater operation. Offshore central stations may be used as repeater stations provided that the licensee is able to maintain control of the station, and in...

  14. Transmembrane Peptides Stabilize Inverted Cubic Phases in a Biphasic Length-Dependent Manner: Implications for Protein-Induced Membrane Fusion

    PubMed Central

    Siegel, D. P.; Cherezov, V.; Greathouse, D. V.; Koeppe, R. E.; Killian, J. Antoinette; Caffrey, M.

    2006-01-01

    WALP peptides consist of repeating alanine-leucine sequences of different lengths, flanked with tryptophan “anchors” at each end. They form membrane-spanning α-helices in lipid membranes, and mimic protein transmembrane domains. WALP peptides of increasing length, from 19 to 31 amino acids, were incorporated into N-monomethylated dioleoylphosphatidylethanolamine (DOPE-Me) at concentrations up to 0.5 mol % peptide. When pure DOPE-Me is heated slowly, the lamellar liquid crystalline (Lα) phase first forms an inverted cubic (QII) phase, and the inverted hexagonal (HII) phase at higher temperatures. Using time-resolved x-ray diffraction and slow temperature scans (1.5°C/h), WALP peptides were shown to decrease the temperatures of QII and HII phase formation (TQ and TH, respectively) as a function of peptide concentration. The shortest and longest peptides reduced TQ the most, whereas intermediate lengths had weaker effects. These findings are relevant to membrane fusion because the first step in the Lα/QII phase transition is believed to be the formation of fusion pores between pure lipid membranes. These results imply that physiologically relevant concentrations of these peptides could increase the susceptibility of biomembrane lipids to fusion through an effect on lipid phase behavior, and may explain one role of the membrane-spanning domains in the proteins that mediate membrane fusion. PMID:16214859

  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. A Semiparametric Bayesian Model for Repeatedly Repeated Binary Outcomes

    PubMed Central

    Quintana, Fernando A.; Müller, Peter; Rosner, Gary L.; Relling, Mary V.

    2009-01-01

    Summary We discuss the analysis of data from single nucleotide polymorphism (SNP) arrays comparing tumor and normal tissues. The data consist of sequences of indicators for loss of heterozygosity (LOH) and involve three nested levels of repetition: chromosomes for a given patient, regions within chromosomes, and SNPs nested within regions. We propose to analyze these data using a semiparametric model for multi-level repeated binary data. At the top level of the hierarchy we assume a sampling model for the observed binary LOH sequences that arises from a partial exchangeability argument. This implies a mixture of Markov chains model. The mixture is defined with respect to the Markov transition probabilities. We assume a nonparametric prior for the random mixing measure. The resulting model takes the form of a semiparametric random effects model with the matrix of transition probabilities being the random effects. The model includes appropriate dependence assumptions for the two remaining levels of the hierarchy, i.e., for regions within chromosomes and for chromosomes within patient. We use the model to identify regions of increased LOH in a dataset coming from a study of treatment-related leukemia in children with an initial cancer diagnostic. The model successfully identifies the desired regions and performs well compared to other available alternatives. PMID:19746193

  18. Lower-Temperature Invert Design For Diffusion Barrier

    SciTech Connect

    Bruce Stanley

    2001-07-30

    The objective of this analysis is to advance the state of the subsurface facilities design to primarily support the ''Yucca Mountain Science and Engineering Report'' (DOE 2001) and to also support the preparation and revision of System Description Document's Section 2 system descriptions (CRWMS M&O 2001, pp. 9 and 11). The results may also eventually support the License Application (CRWMS M&O 2001, p. 3). The Performance Assessment Department will be the primary user of the information generated and will be used in abstraction modeling for the lower-temperature scenario (CRWMS M&O 200 1, p. 27). This analysis will evaluate the invert relative to the lower- and higher-temperature conditions in accordance with the primary tasks below. Invert design is a major factor in allowing water entering the drift to pass freely and enter the drift floor without surface ponding and in limiting diffusive transport into the host rock. Specific cost effective designs will be conceptualized under the new lower-temperature conditions in this analysis. Interfacing activities and all aspects of Integrated Safety Management and Nuclear Culture principles are included in this work scope by adhering to the respective principles during this design activity and by incorporating safety into the design analysis (CRWMS M&O 2001, p. 8). Primary tasks of this analysis include identifying available design information from existing sources on the invert as a diffusive barrier, developing concepts that reduce the amount steel, and developing other design features that accommodate both lower- and higher-temperature operating modes (CRWMS M&O 2001, p.16).

  19. 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.

  20. Processing Facial Expressions of Emotion: Upright vs. Inverted Images

    PubMed Central

    Bimler, David L.; Skwarek, Slawomir J.; Paramei, Galina V.

    2012-01-01

    We studied discrimination of briefly presented upright vs. inverted emotional facial expressions (FEs), hypothesizing that inversion would impair emotion decoding by disrupting holistic FE processing. Stimuli were photographs of seven emotion prototypes, of a male and female poser (Ekman and Friesen, 1976), and eight intermediate morphs in each set. Subjects made speeded Same/Different judgments of emotional content for all upright (U) or inverted (I) pairs of FEs, presented for 500 ms, 100 times each pair. Signal Detection Theory revealed the sensitivity measure d′ to be slightly but significantly higher for the upright FEs. In further analysis using multidimensional scaling (MDS), percentages of Same judgments were taken as an index of pairwise perceptual similarity, separately for U and I presentation mode. The outcome was a 4D “emotion expression space,” with FEs represented as points and the dimensions identified as Happy–Sad, Surprise/Fear, Disgust, and Anger. The solutions for U and I FEs were compared by means of cophenetic and canonical correlation, Procrustes analysis, and weighted-Euclidean analysis of individual differences. Differences in discrimination produced by inverting FE stimuli were found to be small and manifested as minor changes in the MDS structure or weights of the dimensions. Solutions differed substantially more between the two posers, however. Notably, for stimuli containing elements of Happiness (whether U or I), the MDS structure showed signs of implicit categorization, indicating that mouth curvature – the dominant feature conveying Happiness – is visually salient and receives early processing. The findings suggest that for briefly presented FEs, Same/Different decisions are dominated by low-level visual analysis of abstract patterns of lightness and edge filters, but also reflect emerging featural analysis. These analyses, insensitive to face orientation, enable initial positive/negative Valence categorization of FEs

  1. Learning under stress: the inverted-U-shape function revisited.

    PubMed

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

    2010-10-01

    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 (RAWM). Variations in stress intensity were induced using different water temperatures (25°C, 19°C, and 16°C), which elicited increased plasma corticosterone levels. During spatial training over three consecutive days, an inverted-U shape was found, with animals trained at 19°C making fewer errors than animals trained at either higher (16°C) or lower (25°C) stress conditions. Interestingly, this function was already observed by the last trial of day 1 and maintained on the first day trial of day 2. A long-term recall probe test administered under equal temperature conditions (20°C) revealed differences in performance according to the animals' former training conditions; i.e., platform searching for rats trained at 25°C was less accurate than for rats trained at either 16°C or 19°C. In reversal learning, groups trained at both 19°C and 25°C showed better performance than the 16°C group. We also found an interaction between anxiety and exploration traits on how individuals were affected by stressors during spatial learning. In summary, our findings confirm, for the first time, the existence of an inverted-U-shape memory function according to stressor intensity during the early learning and memory phases in a hippocampus-dependent task, and indicate the existence of individual differences related to personality-like profiles for performance at either high or low stress conditions.

  2. 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.

  3. 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.

  4. Inverted-wedge silica resonators for controlled and stable coupling.

    PubMed

    Bo, Fang; Huang, Steven He; Özdemir, Sahin Kaya; Zhang, Guoquan; Xu, Jingjun; Yang, Lan

    2014-04-01

    Silica microresonators with an inverted-wedge shape were fabricated using conventional semiconductor fabrication methods. The measured quality factors of the resonators were greater than 10(6) in 1550 nm band. Controllable coupling from undercoupling to the overcoupling regime through the critical coupling point was demonstrated by horizontally moving a fiber taper while in touch with the top surface of the resonator. The thin outer ring of the resonator provided a support for the fiber taper leading to robust stable coupling. PMID:24686619

  5. 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.

  6. Advanced static compensation using a multilevel GTO thyristor inverter

    SciTech Connect

    Menzies, R.W.; Zhuang, Y.

    1995-04-01

    This paper investigates the possibility of using the multilevel gate turn-off (GTO) thyristor inverter as an advanced static var compensator (STATCON). The studies have indicated that the design shows promise and that the fundamental frequency switching of the GTO thyristors is superior to various forms of pulse-width modulation. The main advantages of the multilevel STATCON over other types of STATCON is that each individual GTO thyristor is clamped to a dc voltage and can be switched independently. Hence a staircase type of output voltage can be used to reduce the harmonics, the filtering requirements and the switching losses.

  7. 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.

  8. Direct and inverted nematic dispersions for soft matter photonics.

    PubMed

    Muševič, I; Skarabot, M; Humar, M

    2011-07-20

    General properties and recent developments in the field of nematic colloids and emulsions are discussed. The origin and nature of pair colloidal interactions in the nematic colloids are explained and an overview of the stable colloidal 2D crystalline structures and superstructures discovered so far is given. The nature and role of topological defects in the nematic colloids is discussed, with an emphasis on recently discovered entangled colloidal structures. Applications of inverted nematic emulsions and binding force mechanisms in nematic colloids for soft matter photonic devices are discussed.

  9. 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.

  10. 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.

  11. Coupled Inverted Pendula Model of Competition and Cooperation

    NASA Astrophysics Data System (ADS)

    Yoshida, Katsutoshi; Ohta, Hiroki

    A coupled inverted pendula model of competition and cooperation is proposed to develop a purely mechanical implementation comparable to the Lotka-Volterra competition model. It is shown numerically that the proposed model can produce the four stable equilibriums analogous to ecological coexistence, two states of dominance, and scramble. The authors also propose two types of open-loop strategies to switch the equilibriums. The proposed strategies can be associated with an attack and a counter attack of agents through a metaphor of martial arts.

  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. 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

  14. 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.

  15. A Self-Oscillating Inverter System With Optimal PWM Pattern

    NASA Astrophysics Data System (ADS)

    Kobayashi, Hisato; Thsuda, Akira

    1987-10-01

    In this paper, we realize an advanced inverter system consists of a reference oscillator, a discrete type arithmetic operation circuit and a switching circuit. The arithmetic operation circuit determines the switching timing (PWM pattern) automatically on the basis of the time sequence data of the difference between the current and the reference signal. This circuit is synthesized by using bang-bang servo technique and it can be implemented by using several BBD elements and operational amplifiers. This circuit is valid for fairly wide change of the magnitude and frequency of the reference input and some variation of the load impedance.

  16. 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.

  17. Robust sliding mode control applied to double Inverted pendulum system

    NASA Astrophysics Data System (ADS)

    Mahjoub, Sonia; Mnif, Faiçal; Derbel, Nabil

    2009-03-01

    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.

  18. 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.

  19. Repeated checking causes memory distrust.

    PubMed

    van den Hout, Marcel; Kindt, Merel

    2003-03-01

    This paper attempts to explain why in obsessive-compulsive disorder (OCD) checkers distrust in memory persists despite extensive checking. It is argued that: (1) repeated checking increases familiarity with the issues checked; (2) increased familiarity promotes conceptual processing which inhibits perceptual processing; (3) inhibited perceptual processing makes recollections less vivid and detailed and finally; (4) reduction in vividness and detail promotes distrust in memory. An interactive computer animation was developed in which participants had to perform checking rituals on a virtual gas stove. Two separate experiments were carried out with n=39 (Experiment I) and n=40 (Experiment II) healthy participants. In both studies, the control group and the experimental group were given the same pre-test and post-test on the virtual gas stove. In between, the experimental group engaged in 'relevant checking', i.e. checking the gas stove, while the control group engaged in 'irrelevant checking', i.e. checking virtual light bulbs. In both experiments there were powerful effects of repeated 'relevant checking': while actual memory accuracy remained unaffected, the vividness and detail of the recollections were greatly reduced. Most pertinently, in both experiments relevant checking undermined confidence in memory. No such effects were observed in the control group. One might argue that the pre-test/post-test design may have made the control group anticipate a memory assessment at the post-test and that this artifact made them relatively alert producing memory confidence at post test that was artificially high. A third experiment was carried out (n=2 x 20) in which no pre-test was given while, other than that, Experiment III was identical to the first two experiments. Results confirmed earlier findings: compared to the irrelevant checking control group, recollections in the relevant checking group were non-vivid, non-detailed while confidence in memory was low. The theory

  20. 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.

  1. 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.

  2. TOO Observations Soft Gamma Repeaters

    NASA Technical Reports Server (NTRS)

    vanParadijs, J.

    1998-01-01

    The goal of the project was to study the X-ray properties of the persistent and burst emission of Soft Gamma Repeaters (SGRs) during periods of burst activity. We monitored this activity with BATSE on the Compton Gamma-Ray Observatory, and made X-ray observations with the Rossi X-ray Timing Explorer (RXTE). SGR1806-20 became active in October 1996. We made observations with the PCA on the RXTE in November 1996. In the RXTE data we detected several hundred brief SGR events, which occurred in clear bunches, and persistent emission. From a Fouder analysis of the persistent emission (excluding time intervals with bursts) we found a period of 7.47 s. These pulsations are also present in RXTE data taken several weeks later (PI Dr. T. Strohmayer), which were combined with our data. Comparison with ASCA data taken in 1993 and 1995 shows that the period, which reflects the spin of a neutron star, increases on a time scale of 1500 years. These results show that SGR1 806-20 is a neutron star with a superstrong magnetic field (about 1"15) Gauss), thereby establishing, for the first time, the existence of magnetars.

  3. 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.

  4. 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.

  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. 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

  7. 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

  8. Strengthening concept learning by repeated testing.

    PubMed

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

    2014-02-01

    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.

  9. 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.

  10. 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.

  11. 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

  12. Inverted methoxypyridinium phthalocyanines for PDI of pathogenic bacteria.

    PubMed

    Lourenço, Leandro M O; Sousa, Andreina; Gomes, Maria C; Faustino, Maria A F; Almeida, Adelaide; Silva, Artur M S; Neves, Maria G P M S; Cavaleiro, José A S; Cunha, Ângela; Tomé, João P C

    2015-10-01

    Phthalocyanines (Pc) are photoactive molecules that can absorb and emit light in a large range of the UV-Vis spectrum with recognized potential for medical applications. Considering the biomedical applications an important limitation of these compounds is their low solubility in water. The use of suitable pyridinium groups on Pc is a good strategy to solve this drawback and to make them more effective to photoinactivate Gram-negative bacteria via a photodynamic inactivation (PDI) approach. Herein, an easy synthetic access to obtain inverted tetra- and octa-methoxypyridinium phthalocyanines (compounds 5 and 6) and also their efficiency to photoinactivate a recombinant bioluminescent strain of Escherichia coli is described. The obtained results were compared with the ones obtained when more conventional thiopyridinium phthalocyanines (compounds 7 and 8) were used. This innovative study comparing thiopyridinium and inverted methoxypyridinium moieties on cationic Pc is reported for the first time taking into account the efficiency of singlet oxygen ((1)O2) generation, water solubility and uptake properties.

  13. Inverted Internal Limiting Membrane Flap For Large Traumatic Macular Holes

    PubMed Central

    Abou Shousha, Mohsen Ahmed

    2016-01-01

    Abstract 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

  14. 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

  15. High-power, null-type, inverted pendulum thrust stand

    NASA Astrophysics Data System (ADS)

    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.

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. De Novo Repeat Classification and Fragment Assembly

    PubMed Central

    Pevzner, Paul A.; Tang, Haixu; Tesler, Glenn

    2004-01-01

    Repetitive sequences make up a significant fraction of almost any genome, and an important and still open question in bioinformatics is how to represent all repeats in DNA sequences. We propose a new approach to repeat classification that represents all repeats in a genome as a mosaic of sub-repeats. Our key algorithmic idea also leads to new approaches to multiple alignment and fragment assembly. In particular, we show that our FragmentGluer assembler improves on Phrap and ARACHNE in assembly of BACs and bacterial genomes. PMID:15342561

  1. Tandem repeats derived from centromeric retrotransposons

    PubMed Central

    2013-01-01

    Background Tandem repeats are ubiquitous and abundant in higher eukaryotic genomes and constitute, along with transposable elements, much of DNA underlying centromeres and other heterochromatic domains. In maize, centromeric satellite repeat (CentC) and centromeric retrotransposons (CR), a class of Ty3/gypsy retrotransposons, are enriched at centromeres. Some satellite repeats have homology to retrotransposons and several mechanisms have been proposed to explain the expansion, contraction as well as homogenization of tandem repeats. However, the origin and evolution of tandem repeat loci remain largely unknown. Results CRM1TR and CRM4TR are novel tandem repeats that we show to be entirely derived from CR elements belonging to two different subfamilies, CRM1 and CRM4. Although these tandem repeats clearly originated in at least two separate events, they are derived from similar regions of their respective parent element, namely the long terminal repeat (LTR) and untranslated region (UTR). The 5′ ends of the monomer repeat units of CRM1TR and CRM4TR map to different locations within their respective LTRs, while their 3′ ends map to the same relative position within a conserved region of their UTRs. Based on the insertion times of heterologous retrotransposons that have inserted into these tandem repeats, amplification of the repeats is estimated to have begun at least ~4 (CRM1TR) and ~1 (CRM4TR) million years ago. Distinct CRM1TR sequence variants occupy the two CRM1TR loci, indicating that there is little or no movement of repeats between loci, even though they are separated by only ~1.4 Mb. Conclusions The discovery of two novel retrotransposon derived tandem repeats supports the conclusions from earlier studies that retrotransposons can give rise to tandem repeats in eukaryotic genomes. Analysis of monomers from two different CRM1TR loci shows that gene conversion is the major cause of sequence variation. We propose that successive intrastrand deletions

  2. 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…

  3. 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)

  4. 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…

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. The inverted Batman incision: a new incision in transcolumellar incision for open rhinoplasty.

    PubMed

    Nakanishi, Yuji; Nagasao, Tomohisa; Shimizu, Yusuke; Miyamoto, Junpei; Fukuta, Keizo; Kishi, Kazuo

    2013-12-01

    Columellar and nostril shapes often present irregularity after transcolumellar incision for open rhinoplasty, because of the contracture of the incised wound. The present study introduces a new technique to prevent this complication, and verifies its efficacy in improving cosmetic appearance. In our new method, a zig-zag incision with three small triangular flaps is made on the columella and in the pericolumellar regions of the bilateral nostril rims. Since the shape of the incision resembles the contour of an inverted "batman", we term our new method the "Inverted Batman" incision. To verify the effectiveness of the Inverted Batman incision, aesthetic evaluation was conducted for 21 patients operated on using the conventional transcolumellar incision (Conventional Group) and 19 patients operated on using the Inverted Batman incision (Inverted Batman Group). The evaluation was performed by three plastic surgeons, using a four-grade scale to assess three separate items: symmetry of bilateral soft triangles, symmetry of bilateral margins of the columella, and evenness of the columellar surface. The scores of the two groups for these three items were compared using a non-parametric test (Mann-Whitney U-test). With all three items, the Inverted Batman group patients present higher scores than Conventional Group patients. The Inverted Batman incision is effective in preserving the correct anatomical structure of the columella, soft triangle, and nostril rims. Hence, we recommend the Inverted Batman incision as a useful technique for open rhinoplasty.

  10. 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.

  11. 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

  12. Suspended Patch Antennas With Electromagnetically Coupled Inverted Microstrip Feed for Circular Polarization

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.

    2000-01-01

    The paper demonstrates a suspended nearly square patch antenna with offset feed and a square patch antenna with truncated corners for circular polarization. The antennas are excited by an electromagnetically coupled inverted microstrip feed. In addition a new transition between conventional microstrip and inverted microstrip is proposed. The measured results include the axial ratio and the impedance bandwidth of the antennas.

  13. A solid-state single-phase pulse-width-code modulated inverter

    NASA Astrophysics Data System (ADS)

    Baranov, V. K.; Kriuchkov, V. V.; Malyshkov, G. M.; Khrunova, S. S.; Iakovlev, A. N.

    Analog-digital and digital control schemes for single-phase thyristor pulse-width modulated inverters are presented which allow the selective exclusion of a series of higher harmonics from the approximating voltage. The use of more complex control schemes is shown to be justified in the case of high-power inverters.

  14. Alphoidless centromere of a familial unstable inverted Y chromosome.

    PubMed

    Rivera, H; Vassquez, A I; Ayala-Madrigal, M L; Ramirez-Dueñas, M L; Davalos, I P

    1996-01-01

    We report on a 3-generation pedigree in which an inverted unstable Y chromosome had no phenotypical or reproductive repercussion despite a sizable proportion of secondary aneuploidies (mainly 45, X cells) in lymphocytes. This chromosome was metacentric and had a single Cd-positive primary constriction, but occasionally assumed a normal acrocentric aspect. FISH using the probe DYZ3 revealed a single strong signal; unexpectedly, the signal was outside the primary constriction and appeared to map in the middle of p, that is, at the usual centromeric localisation. Therefore, this chromosome should be regarded as a remarkable pseudodicentric because the major alphoid array was located at the inactive centromere but not at the active one. This chromosome may have resulted from a) a transcentric inversion with the 48 bp satellite array of proximal Yq being relocated next to the Yq heterochromatin, or b) an intrachromosomal insertion of nonalphoid centromeric sequences.

  15. Noisy inverted pendulums with time-delayed feedback: Statistical Dynamics

    NASA Astrophysics Data System (ADS)

    Milton, John G.

    2001-03-01

    The question of how an inverted pendulum can be stabilized has puzzled scientists for over 300 years. Studies of postural sway and stick balancing at the fingertip provide insights into how the human nervous system solves this problem. Time delays and noise are intrinsic features of the neural control and thus models are in the form of stochastic delay-differential equations. Examples are presented to show that the statistical properties of the fluctuations in posture and stick balancing are dominated by noise-dependent, nonlinear phenomena: noise-induced switching between limit cycle attractors (postural sway) and "on-off intermittency" arising from the stochastic forcing of a control parameter across a stability boundary (stick balancing). The existence of these phenomena is difficult to reconcile with classical concepts of neural feedback control.

  16. Cone Beam Computed Tomography Evaluation of Inverted Mesiodentes.

    PubMed

    Al-Sehaibany, Fares S; Marzouk, Hazem M; Salama, Fouad S

    2016-01-01

    A mesiodens is the most common type of supernumerary teeth. The purpose of this report is to present a rare occurrence of non-syndromic impacted inverted mesiodentes in an 8.5-year-old boy who presented with a chief complaint of delayed eruption of his permanent maxillary left central incisor. Occlusal and panoramic radiographs, as well as cone beam computed tomography (CBCT) with a three-dimensional (3-D) reconstruction image, confirmed that one supernumerary tooth had perforated the nasal fossa floor and the other was in close approximation to the to the same site. Surgical removal of both mesiodentes was indicated. Radiographic evidence of complete healing was observed 12 months following surgical removal. The use of CBCT with a 3-D reconstruction image as a tool in diagnosis and evaluation of healing after surgical removal is recommended.

  17. 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.

  18. 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.

  19. An invertible linearization map for the quartic oscillator

    SciTech Connect

    Anderson, Robert L.

    2010-12-15

    The set of world lines for the nonrelativistic quartic oscillator satisfying Newton's equation of motion for all space and time in 1-1 dimensions with no constraints other than the 'spring' restoring force is shown to be equivalent (1-1-onto) to the corresponding set for the harmonic oscillator. This is established via an energy preserving invertible linearization map which consists of an explicit nonlinear algebraic deformation of coordinates and a nonlinear deformation of time coordinates involving a quadrature. In the context stated, the map also explicitly solves Newton's equation for the quartic oscillator for arbitrary initial data on the real line. This map is extended to all attractive potentials given by even powers of the space coordinate. It thus provides classes of new solutions to the initial value problem for all these potentials.

  20. 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.

  1. 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).

  2. Characteristics of GaAs with inverted thermal conversion

    NASA Technical Reports Server (NTRS)

    Kang, C. H.; Lagowski, J.; Gatos, H. C.

    1987-01-01

    GaAs crystals exhibiting inverted thermal conversion (ITC) of resistivity were investigated in conjunction with standard semiinsulating (SI) GaAs regarding characteristics important in device processing. It was established that dislocation density and Si implant activation are unaffected by transformation to the ITC state. However, in ITC GaAs the controlled increase of the EL2 (native midgap donor) concentration during annealing makes it possible to attain resistivities one order of magnitude greater (e.g., about 10 to the 9th ohm cm of 300 K) than those attained in standard SI GaAs (e.g., 10 to the 7th-10 to the 8th ohm cm).

  3. 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.

  4. Inverted television and video games to maintain neck extension.

    PubMed

    Foley, K H; Kaulkin, C; Palmieri, T L; Greenhalgh, D G

    2001-01-01

    It has been the standard of care in our pediatric facility to keep patients on strict bedrest with the neck in hyperextension for 5 days after a neck contracture release or grafting. Multiple methods have been used to help maintain neck immobility after grafting. It has been challenging to maintain strict bedrest protocols, because of decreased compliance and boredom. To address this issue, we examined common sedentary diversional activities engaged in by children. We decided to use video games to facilitate the intrinsic motivation of play. The monitor of a video game activity was inverted and placed behind the head of the bed so that the child could maintain proper neck positioning. We found the activity to be beneficial in many aspects. It helped maintain neck positioning, decreased the demand for individual interventions, and provided opportunities for improving self-confidence.

  5. 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.

  6. Cone Beam Computed Tomography Evaluation of Inverted Mesiodentes.

    PubMed

    Al-Sehaibany, Fares S; Marzouk, Hazem M; Salama, Fouad S

    2016-01-01

    A mesiodens is the most common type of supernumerary teeth. The purpose of this report is to present a rare occurrence of non-syndromic impacted inverted mesiodentes in an 8.5-year-old boy who presented with a chief complaint of delayed eruption of his permanent maxillary left central incisor. Occlusal and panoramic radiographs, as well as cone beam computed tomography (CBCT) with a three-dimensional (3-D) reconstruction image, confirmed that one supernumerary tooth had perforated the nasal fossa floor and the other was in close approximation to the to the same site. Surgical removal of both mesiodentes was indicated. Radiographic evidence of complete healing was observed 12 months following surgical removal. The use of CBCT with a 3-D reconstruction image as a tool in diagnosis and evaluation of healing after surgical removal is recommended. PMID:27620520

  7. EMI from solar panels and inverters. A subcontract report

    SciTech Connect

    Not Available

    1983-01-01

    Results are given of an exploratory investigation to ascertain the potential of electromagnetic interference (EMI) caused by radiation from photovoltaic (PV) systems. This includes a determination of the appropriate parameters to be measured and a review of present standards with emphasis on the FCC docket on incidental radiators. It also includes small residential installations having roof-mounted PV arrays. The results will be used to make recommendations as to what further work, if any, is needed to ensure that EMI from a PV system is negligible. Measured data so far show that the inverters in the solar-panel system tested caused severe EMI problems in the AM broadcast band (0.5 to 1.6 MH/sub 2/), while FM and television reception was not significantly affected.

  8. Alpha detection in pipes using an inverting membrane scintillator

    SciTech Connect

    Kendrick, D.T.; Cremer, C.D.; Lowry, W.; Cramer, E.

    1995-12-31

    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. The measurement methodology under development overcomes the limitations associated with conventional hand-held survey instruments by remotely emplacing an alpha scintillator in direct contact with the interior pipe surface over the entire length to be characterized. This is accomplished by incorporating a suitable scintillator into the otherwise clear membrane material. Alpha particles emitted from the interior pipe surface will intersect the membrane, resulting in the emission of light pulses from the scintillator. A photodetector, towed by the inverting membrane, is used to count these light pulses as a function of distance into the pipe, thereby producing a log of the surface alpha contamination levels. It is anticipated that the resulting system will be able to perform measurements in pipes as small as two inches in diameter, and several hundred feet in length.

  9. Research on vision control system for inverted pendulum

    NASA Astrophysics Data System (ADS)

    Jin, Xiaolin; Bian, Yongming; Jiang, Jia; Li, Anhu; Jiang, Xuchun; Zhao, Fangwei

    2010-10-01

    This paper focuses on the study and experiment of vision control system for an inverted pendulum. To solve some key technical problems, the hardware platform and the software flow of the control system have been designed. The whole control system is composed of vision module and motion control module. The vision module is based on "CCD camera", the motion control module is based on "Motion Control Card, Servo Driver and Servo Motor", and the software is based on LabView. The main research contents and contributions of this paper are summarized as follows: (1) Analyze the functional requirements of the vision control system about the inverted pendulum, developing the hardware platform and planning the overall arrangement of the system; (2) Design the image processing flow and the recognition track process of the moving objects. The accurate position of the pendulum can be obtained from the image through the flow, which concludes image pretreatment, image segmentation and image post-processing; (3) Design the software structure of the control system and write the program code. It is convenient to update and maintain the control software due to the modularity of the system. Some key technical problems in the software have been solved, so the flexibility and reliability of the control system are improved; (4) Build the experimental platform and set the key parameters of the vision control system through experiments. It is proved that the chosen scheme of this paper is feasible. The experiment provides the basis for the development and application of the whole control system.

  10. 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.

  11. Fault protection in a multilevel inverter implementation of a static condenser

    SciTech Connect

    Sinha, G.; Hochgraf, C.; Lasseter, R.H.; Divan, D.M.; Lipo, T.A.

    1995-12-31

    Multilevel inverters are well suited for static condenser implementation in utility systems. With multilevel inverters, it is possible to realize low distortion voltage waveforms and keep losses low using suitable switching schemes. The complex topology of these inverters coupled with the large number of devices used increases the probability of device failure. In this paper, the fault modes of a multilevel inverter are investigated with special emphasis on the five level inverter. The main focus of the paper is on device failure and the corresponding impact on the operating conditions and resulting stresses. The presence of redundant states offers the possibility of continuing operation with inferior bus and device utilization following a fault. Failure of some devices is more critical than the failure of others, thereby emphasizing the need for adding redundant devices.

  12. Stabilization of a Power System including Inverter Type Distributed Generators by the Virtual Synchronous Generator

    NASA Astrophysics Data System (ADS)

    Sakimoto, Kenichi; Miura, Yushi; Ise, Toshifumi

    The capacity of Distributed Generators (DGs) connected to grid by inverters are growing year and year. The inverters are generally controlled by PLL (Phase Locked Loop) in order to synchronize with power system frequency. Power systems will become unstable, if the capacity of inverter type DGs become larger and larger, because inverter frequency is controlled just to follow the frequency decided by other synchronous generators. There is the idea that inverters are controlled to behave like a synchronous generator. This concept is called Virtual Synchronous Generator (VSG). In this paper, a control scheme of VSG is presented, and the design method of required energy storage and the ability of grid stabilizing control by VSG is investigated by computer simulations.

  13. 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.

  14. 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.

  15. 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

  16. Study on model current predictive control method of PV grid- connected inverters systems with voltage sag

    NASA Astrophysics Data System (ADS)

    Jin, N.; Yang, F.; Shang, S. Y.; Tao, T.; Liu, J. S.

    2016-08-01

    According to the limitations of the LVRT technology of traditional photovoltaic inverter existed, this paper proposes a low voltage ride through (LVRT) control method based on model current predictive control (MCPC). This method can effectively improve the photovoltaic inverter output characteristics and response speed. The MCPC method of photovoltaic grid-connected inverter designed, the sum of the absolute value of the predictive current and the given current error is adopted as the cost function with the model predictive control method. According to the MCPC, the optimal space voltage vector is selected. Photovoltaic inverter has achieved automatically switches of priority active or reactive power control of two control modes according to the different operating states, which effectively improve the inverter capability of LVRT. The simulation and experimental results proves that the proposed method is correct and effective.

  17. A HSV-1 variant (1720) generates four equimolar isomers despite a 9200-bp deletion from TRL and sequences between 9200 np and 97,000 np in inverted orientation being covalently bound to sequences 94,000-126,372 np.

    PubMed

    Harland, J; Brown, S M

    1992-08-01

    The genome structure of a spontaneously generated HSV-1 strain 17 variant, 1720, has been determined by restriction endonuclease and Southern blot analysis. The short segment of 1720 is unaltered compared to the parental strain 17 genome, whereas the long segment is extensively rearranged. Almost all of TRL (approximately 9.2 kb) has been deleted and consequently IRL is converted into unique sequence. Sequences from approximately 9200 nucleotide position (np) to 97,000 np are present in inverted orientation, covalently bound to sequences in the prototype orientation from approximately 94,000 np to the L/S junction at 126,372 np. Thus, sequences from 94,000 np to 97,000 np are now diploid, with one copy in the normal orientation and location, and the other at the long terminus as an inverted repeat; no inversion of the intervening unique sequences occurs about this novel inverted repeat. In contrast, normal inversions of the long and short segments occur to give four equimolar genomic isomers, indicating that the novel long terminus has gained an "a" sequence. The duplication of sequences between 94,000 np and 97,000 np results in a genome containing two copies of UL43 and one complete and one partial copy each of genes UL42 and UL44 encoding the 65 kD DNA-binding protein and glycoprotein C, respectively. The variant has been shown to grow normally in vitro following high multiplicity infection.

  18. Native DNA repeats and methylation in Ascobolus.

    PubMed Central

    Goyon, C; Rossignol, J L; Faugeron, G

    1996-01-01

    We identified two classes of native dispersed DNA repeats in the Ascobolus genome. The first class consisted of several kilobase long, methylated repeats. These repeats, named Mars (methylated Ascobolus repeated sequences), fell in one family of LINE-like elements and in three families of LTR-containing retrotransposable elements. The methylation features of Mars elements were those expected if they were natural targets for the MIP (methylation induced premeiotically) previously discovered in Ascobolus. The second class consisted of short repeats, approximately 100 bp long, corresponding to 5S rRNA and tRNA genes. As expected from their size, which was too small to allow MIP to occur, they were unmethylated, as were 26 kb of unique sequences tested. These observations are consistent with the hypothesis that MIP is targeted at natural DNA repeats and constitutes a defensive process against the detrimental consequences of the spreading of mobile elements throughout the genome. The 9 kb tandem repeats harbouring the 28S, 18S and 5.8S rRNA genes displayed methylation features suggesting that rDNA methylation proceeds through a process other than MIP. PMID:8811089

  19. Construction and evaluation of photovoltaic power generation and power storage system using SiC field-effect transistor inverter

    NASA Astrophysics Data System (ADS)

    Oku, Takeo; Matsumoto, Taisuke; Hiramatsu, Koichi; Yasuda, Masashi; Ohishi, Yuya; Shimono, Akio; Takeda, Yoshikazu; Murozono, Mikio

    2016-02-01

    A power storage system using spherical silicon (Si) solar cells, maximum power point tracking charge controller, lithium-ion battery and a direct current-alternating current (DC-AC) inverter was constructed. Performance evaluation of the DC-AC inverter was carried out, and the DC-AC conversion efficiencies of the SiC field-effect transistor (FET) inverter was improved compared with those of the ordinary Si-FET based inverter.

  20. The child accident repeater: a review.

    PubMed

    Jones, J G

    1980-04-01

    The child accident repeater is defined as one who has at least three accidents that come to medical attention within a year. The accident situation has features in common with those of the child who has a single accident through simple "bad luck", but other factors predispose him to repeated injury. In the child who has a susceptible personality, a tendency for accident repetition may be due to a breakdown in adjustment to a stressful environment. Prevention of repeat accidents should involve the usual measures considered appropriate for all children as well as an attempt to provide treatment of significant maladjustment and modification of a stressful environment.

  1. 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.

  2. 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…

  3. 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

  4. The Moral Maturity of Repeater Delinquents.

    ERIC Educational Resources Information Center

    Petronio, Richard J.

    1980-01-01

    Differences in moral development (as conceived by Kohlberg) were examined in a sample of delinquent teenagers. The repeater group was not found, as had been hypothesized, to be lower on moral maturity than those who engaged in less delinquency. (GC)

  5. 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.

  6. Repeat hepatectomy for colorectal liver metastases.

    PubMed Central

    Adam, R; Bismuth, H; Castaing, D; Waechter, F; Navarro, F; Abascal, A; Majno, P; Engerran, L

    1997-01-01

    OBJECTIVE: The authors assess the long-term results of repeat hepatectomies for recurrent metastases of colorectal cancer and determine the factors that can predict survival. SUMMARY BACKGROUND DATA: Safer techniques of hepatic resection have allowed surgeons to consider repeat hepatectomy for colorectal metastases in an increasing number of patients. However, higher operative bleeding and increased morbidity have been reported after repeat hepatectomies, and the long-term benefit of these procedures needs to be evaluated. STUDY POPULATION: Sixty-four patients from a group of 243 patients resected for colorectal liver metastases were submitted to 83 repeat hepatectomies (64 second, 15 third, and 4 fourth hepatectomies). Combined extrahepatic surgery was performed in 21 (25%) of these 83 repeat hepatectomies. RESULTS: There was no intraoperative or postoperative mortality. Operative bleeding was not significantly increased in repeat hepatectomies as compared to first resections. Morbidity and duration of hospital stay were comparable to first hepatectomies. Overall and disease-free survival after a second hepatectomy were 60% and 42%, respectively, at 3 years and 41% and 26%, respectively, at 5 years. Factors of prognostic value on univariate analysis included the curative nature of first and second hepatectomies (p = 0.04 and p = 0.002, respectively), an interval between the two procedures of more than 1 year (p = 0.003), the number of recurrent tumors (p = 0.002), serum carcinoembryonic antigen levels (p = 0.03), and the presence of extrahepatic disease (p = 0.03). Only the curative nature of the second hepatectomy and an interval of more than 1 year between the two procedures were independently related to survival on multivariate analysis. CONCLUSIONS: Repeat hepatectomies can provide long-term survival rates similar to those of first hepatectomies, with no mortality and comparable morbidity. Combined extrahepatic surgery can be required to achieve tumor

  7. Star repeaters for fiber optic links.

    PubMed

    McMahon, D H; Gravel, R L

    1977-02-01

    A star repeater combines the functions of a passive star coupler and a signal regenerating amplifier. By more effectively utilizing the light power radiated by a light emitting diode, the star repeater can, when used with small diameter channels, couple as much power to all receivers of a multiterminal link as would be coupled to the single receiver of a simple point-to-point link.

  8. 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

  9. Variability modes in core flows inverted from geomagnetic field models

    NASA Astrophysics Data System (ADS)

    Pais, M. A.; Morozova, A. L.; Schaeffer, N.

    2014-01-01

    The flow of liquid metal inside the Earth's core produces the geomagnetic field and its time variations. Understanding the variability of those deep currents is crucial to improve the forecast of geomagnetic field variations and may provide relevant information on the core dynamics. The main goal of this study is to extract and characterize the leading variability modes of core flows over centennial periods, and to assess their statistical robustness. To this end, we use flows that we invert from two geomagnetic field models (`gufm1' and `COV-OBS'), and apply principal component analysis and singular value decomposition of coupled fields. The quasi-geostrophic (QG) flows inverted from both geomagnetic field models show similar features. However, `COV-OBS' flows have a less energetic mean and larger time variability. The statistical significance of flow components is tested from analyses performed on subareas of the whole domain. Bootstrapping methods are also used to extract significant flow features required by both `gufm1' and `COV-OBS'. Three main empirical circulation modes emerge, simultaneously constrained by both geomagnetic field models and expected to be robust against the particular a priori used to build them (large-scale QG dynamics). Mode 1 exhibits three large vortices at medium/high latitudes, with opposite circulation under the Atlantic and the Pacific hemispheres. Mode 2 interestingly accounts for most of the variations of the Earth's core angular momentum. In this mode, the regions close to the tangent cylinder and to the equator are correlated, and oscillate with a period between 80 and 90 yr. Each of these two modes is energetic enough to alter the mean flow, sometimes reinforcing the eccentric gyre, and other times breaking it up into smaller circulations. The three main circulation modes added to the mean flow account for about 70 per cent of the flows variability, 90 per cent of the rms total velocities, and 95 per cent of the secular

  10. Multiple degree of freedom inverted pendulum dynamics: Modeling, computation, and experimentation

    NASA Astrophysics Data System (ADS)

    Chen, Cheng-Yuan Jerry

    A pendulum is statically unstable in its upright inverted state due to the Earth's gravitational attraction which points downward. However, with proper forcing, the pendulum can be stabilized in its upright inverted state. Special interest is on periodic vertical forcing applied to the pendulum's base to stabilize it around the upright inverted equilibrium. Many researchers have studied how to stabilize the system by varying various parameters, in particular its amplitude and frequency. Most have focused on the single degree of freedom inverted pendulum case, which with linear assumption can be described via Mathieu's equation. The system stability can then be characterized by Floquet theory. Our focus is on searching for the periodic solutions inside the linearly stable region of the pendulum's inverted state when the pendulum is under proper periodic forcing. Our research shows that under appropriate excitation by controlling the forcing amplitude and frequency, the pendulum can maintain certain periodic orbits around its inverted state which we characterize in a systematic way. In this thesis, we applied four different kinds of geometric realizations of the system response: system time traces, system phase portraits, three dimensional views of the system phase portrait as a function of input forcing, and the system's power spectral density diagram. By analyzing these four diagrams simultaneously, we characterize different kinds of multi-frequency periodic behavior around the pendulum's inverted state. To further discuss the effect of the nonlinearity, we applied perturbation techniques using the normalized forcing amplitude as a perturbation parameter to carry out the approximate periodic solutions on a single degree of freedom inverted pendulum nonlinear model. We also discuss the multiple degree of freedom inverted pendulum system. Both numerical simulation and experiments were performed and detailed comparisons are discussed. Our numerical simulations show

  11. Structures of designed armadillo-repeat proteins show propagation of inter-repeat interface effects.

    PubMed

    Reichen, Christian; Madhurantakam, Chaithanya; Hansen, Simon; Grütter, Markus G; Plückthun, Andreas; Mittl, Peer R E

    2016-01-01

    The armadillo repeat serves as a scaffold for the development of modular peptide-recognition modules. In order to develop such a system, three crystal structures of designed armadillo-repeat proteins with third-generation N-caps (YIII-type), four or five internal repeats (M-type) and second-generation C-caps (AII-type) were determined at 1.8 Å (His-YIIIM4AII), 2.0 Å (His-YIIIM5AII) and 1.95 Å (YIIIM5AII) resolution and compared with those of variants with third-generation C-caps. All constructs are full consensus designs in which the internal repeats have exactly the same sequence, and hence identical conformations of the internal repeats are expected. The N-cap and internal repeats M1 to M3 are indeed extremely similar, but the comparison reveals structural differences in internal repeats M4 and M5 and the C-cap. These differences are caused by long-range effects of the C-cap, contacting molecules in the crystal, and the intrinsic design of the repeat. Unfortunately, the rigid-body movement of the C-terminal part impairs the regular arrangement of internal repeats that forms the putative peptide-binding site. The second-generation C-cap improves the packing of buried residues and thereby the stability of the protein. These considerations are useful for future improvements of an armadillo-repeat-based peptide-recognition system. PMID:26894544

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Evaluation of photovoltaic power generation system using spherical silicon solar cells and SiC-FET inverter

    NASA Astrophysics Data System (ADS)

    Matsumoto, Taisuke; Oku, Takeo; Hiramatsu, Koichi; Yasuda, Masashi; Shirahata, Yasuhiro; Shimono, Akio; Takeda, Yoshikazu; Murozono, Mikio

    2016-02-01

    A photovoltaic power generation system using spherical silicon (Si) solar cells and silicon carbide (SiC) field effect transistor (FET) inverter for photovoltaic applications was constructed and evaluated. The spherical Si solar cells were connected to the SiC-FET inverter and were used as a power source. Comparing the photovoltaic power generation system using an ordinary Si-FET inverter, direct current-alternating current conversion efficiencies of the SiC-FET inverter were improved due to reduction of power loss in the SiC-FET inverter.

  17. Nonlinear analysis of a family of LC tuned inverters. [dc to square wave circuits for power conditioning

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

    A family of four dc-to-square-wave LC tuned inverters are analyzed using singular point. Limit cycles and waveshape characteristics are given for three modes of oscillation: quasi-harmonic, relaxation, and discontinuous. An inverter in which the avalanche breakdown of the transistor emitter-to-base junction occurs is discussed and the starting characteristics of this family of inverters are presented. The LC tuned inverters are shown to belong to a family of inverters with a common equivalent circuit consisting of only three 'series' elements: a five-segment piecewise-linear current-controlled resistor, linear inductor, and linear capacitor.

  18. Inverted Silicon Nanopencil Array Solar Cells with Enhanced Contact Structures

    NASA Astrophysics Data System (ADS)

    Liang, Xiaoguang; Shu, Lei; Lin, Hao; Fang, Ming; Zhang, Heng; Dong, Guofa; Yip, Senpo; Xiu, Fei; Ho, Johnny C.

    2016-09-01

    Although three-dimensional nanostructured solar cells have attracted extensive research attention due to their superior broadband and omnidirectional light-harvesting properties, majority of them are still suffered from complicated fabrication processes as well as disappointed photovoltaic performances. Here, we employed our newly-developed, low-cost and simple wet anisotropic etching to fabricate hierarchical silicon nanostructured arrays with different solar cell contact design, followed by systematic investigations of their photovoltaic characteristics. Specifically, nano-arrays with the tapered tips (e.g. inverted nanopencils) are found to enable the more conformal top electrode deposition directly onto the nanostructures for better series and shunt conductance, but its insufficient film coverage at the basal plane would still restrict the charge carrier collection. In contrast, the low-platform contact design facilitates a substantial photovoltaic device performance enhancement of ~24%, as compared to the one of conventional top electrode design, due to the shortened current path and improved lateral conductance for the minimized carrier recombination and series resistance. This enhanced contact structure can not only maintain excellent photon-trapping behaviors of nanostructures, but also help to eliminate adverse impacts of these tapered nano-morphological features on the contact resistance, providing further insight into design consideration in optimizing the contact geometry for high-performance nanostructured photovoltaic devices.

  19. 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.

  20. Reversible degradation of inverted organic solar cells by concentrated sunlight

    NASA Astrophysics Data System (ADS)

    Tromholt, Thomas; Manor, Assaf; Katz, Eugene A.; Krebs, Frederik C.

    2011-06-01

    Concentrated sunlight was used to study the performance response of inverted P3HT:PCBM organic solar cells after exposure to high intensity sunlight. Correlations of efficiency as a function of solar intensity were established in the range of 0.5-15 suns at three different stages: for a pristine cell, after 30 min exposure at 5 suns and after 30 min of rest in the dark. High intensity exposure introduced a major performance decrease for all solar intensities, followed by a partial recovery of the lost performance over time: at 1 sun only 6% of the initial performance was conserved after the high intensity exposure, while after rest the performance had recovered to 60% of the initial value. The timescale of the recovery effect was studied by monitoring the cell performance at 1 sun after high intensity exposure. This showed that cell performance was almost completely restored after 180 min. The transient state is believed to be a result of the breakdown of the diode behaviour of the ZnO electron transport layer by O2 desorption, increasing the hole conductivity. These results imply that accelerated degradation of organic solar cells by concentrated sunlight is not a straightforward process, and care has to be taken to allow for a sound accelerated lifetime assessment based on concentrated sunlight.

  1. Examining the geometrical model with inverted mass hierarchy for neutrinos

    SciTech Connect

    Honda, Mizue; Tanimoto, Morimitsu

    2007-05-01

    The comprehensive analyses are presented in the model with the inverted mass hierarchy for neutrinos, which follows from a geometrical structure of a (1+5) dimensional space-time where two extra dimensions are compactified on the T{sup 2}/Z{sub 3} orbifold. The model gives two large lepton flavor mixings due to the S{sub 3} structure in the (1+5) dimensional space-time. It also predicts the lightest neutrino mass as m{sub 3}=(1-50)x10{sup -5} eV and the effective neutrino mass responsible for neutrinoless double beta decays as {sub ee}{approx_equal}50 meV. The low energy CP violation, J{sub CP} could be 0.02. On the other hand, the observed baryon asymmetry in the present universe is produced by the nonthermal leptogenesis, which works even at the reheating temperature T{sub R}=10{sup 4}-10{sup 6} GeV. The correlation between the baryon asymmetry and the low energy CP violation is examined in this model.

  2. 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.

  3. Inverted Silicon Nanopencil Array Solar Cells with Enhanced Contact Structures

    PubMed Central

    Liang, Xiaoguang; Shu, Lei; Lin, Hao; Fang, Ming; Zhang, Heng; Dong, Guofa; Yip, SenPo; Xiu, Fei; Ho, Johnny C.

    2016-01-01

    Although three-dimensional nanostructured solar cells have attracted extensive research attention due to their superior broadband and omnidirectional light-harvesting properties, majority of them are still suffered from complicated fabrication processes as well as disappointed photovoltaic performances. Here, we employed our newly-developed, low-cost and simple wet anisotropic etching to fabricate hierarchical silicon nanostructured arrays with different solar cell contact design, followed by systematic investigations of their photovoltaic characteristics. Specifically, nano-arrays with the tapered tips (e.g. inverted nanopencils) are found to enable the more conformal top electrode deposition directly onto the nanostructures for better series and shunt conductance, but its insufficient film coverage at the basal plane would still restrict the charge carrier collection. In contrast, the low-platform contact design facilitates a substantial photovoltaic device performance enhancement of ~24%, as compared to the one of conventional top electrode design, due to the shortened current path and improved lateral conductance for the minimized carrier recombination and series resistance. This enhanced contact structure can not only maintain excellent photon-trapping behaviors of nanostructures, but also help to eliminate adverse impacts of these tapered nano-morphological features on the contact resistance, providing further insight into design consideration in optimizing the contact geometry for high-performance nanostructured photovoltaic devices. PMID:27671709

  4. Mapping the rupture process of moderate earthquakes by inverting accelerograms

    USGS Publications Warehouse

    Hellweg, M.; Boatwright, J.

    1999-01-01

    We present a waveform inversion method that uses recordings of small events as Green's functions to map the rupture growth of moderate earthquakes. The method fits P and S waveforms from many stations simultaneously in an iterative procedure to estimate the subevent rupture time and amplitude relative to the Green's function event. We invert the accelerograms written by two moderate Parkfield earthquakes using smaller events as Green's functions. The first earthquake (M = 4.6) occurred on November 14, 1993, at a depth of 11 km under Middle Mountain, in the assumed preparation zone for the next Parkfield main shock. The second earthquake (M = 4.7) occurred on December 20, 1994, some 6 km to the southeast, at a depth of 9 km on a section of the San Andreas fault with no previous microseismicity and little inferred coseismic slip in the 1966 Parkfield earthquake. The inversion results are strikingly different for the two events. The average stress release in the 1993 event was 50 bars, distributed over a geometrically complex area of 0.9 km2. The average stress release in the 1994 event was only 6 bars, distributed over a roughly elliptical area of 20 km2. The ruptures of both events appear to grow spasmodically into relatively complex shapes: the inversion only constrains the ruptures to grow more slowly than the S wave velocity but does not use smoothness constraints. Copyright 1999 by the American Geophysical Union.

  5. 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

  6. 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.

  7. 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.

  8. Semiconductor converters/inverters for photovoltaic power supply

    NASA Astrophysics Data System (ADS)

    Longrigg, P.

    The two generic types of DC to AC inverters are discussed, considering inherent problems and prospects for solution. A current source converter uses reference current from the AC utility line to chop the DC into AC using four thyristors as switches. Difficulties exist in that DC current contains lagging quadrature currents and are harmonics rich. Solutions are indicated in the form of tuned filters for controlling harmonics and a static VAR generator for the quadrature demand, except that solving the quadrature problem reintroduces further harmonics. In the voltage-sourced converter, which performs much like a synchronous generator, harmonics are also present and can be eliminated with pulse-width modulation. However, at lower powers, switching accelerates beyond attainable switching speed levels. Finally, a current-fed, force commutated converter is described which commutates ahead of the AC voltage; it may need special filters or buffers in addition to harmonics filters. Further studies are recommended in areas of cost reductions, interface overvoltage protection, harmonics, source stability, safety and code requirements, and utility system protection, all pertinent to photovoltaic power conditioning. Circuitry diagrams and AC V-I graphs are provided.

  9. 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

  10. Surface treatment on polyethylenimine interlayer to improve inverted OLED performance

    NASA Astrophysics Data System (ADS)

    Wei, Chang-Ting; Zhuang, Jin-Yong; Chen, Ya-Li; Zhang, Dong-Yu; Su, Wen-Ming; Cui, Zheng

    2016-10-01

    Polyethylenimine (PEI) interlayer rinsing with different solvents for inverted organic light emitting diodes (OLEDs) is systematically studied in this paper. In comparison with the pristine one, the maximum current efficiency (CE max) and power efficiency (PE max) are enhanced by 21% and 22% for the device rinsing by ethylene glycol monomethyl ether (EEA). Little effect is found on the work function of the PEI interlayer rinsed by deionized water (DI), ethanol (EtOH), and EEA. On the other hand, the surface morphologies of PEI through different solvent treatments are quite different. Our results indicates that the surface morphology is the key to improving the device performance for IOLED as the work function of PEI keeps stable. Project supported by the National Key Basic Research Project of China (Grant No. 2015CB351901), the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA09020201), the Youth Innovation Promotion Association of Chinese Academy of Sciences (Grant No. 2013206), the National Natural Science Foundation of China (Grant No. 21402233), and the Natural Science Foundation of Jiangsu Province, China (Grant Nos. BK2012631 and BK20140387).

  11. Inverted Break-up Behaviour in Continuous Inkjet (CIJ) Printing

    NASA Astrophysics Data System (ADS)

    McIlroy, Claire; Harlen, Oliver; Morrison, Neil

    2014-11-01

    Although droplet creation during continuous jetting of Newtonian fluids has been widely studied, unsolved problems surrounding the break-up dynamics remain. Jetting through a nozzle creates a stream of liquid that is rendered unstable by surface tension. This instability creates a succession of main drops connected by thin filaments, with drop separation determined by the fastest growing wavelength. In order to control break-up and increase printing speeds, continuous inkjet (CIJ) printing exploits the effects of finite amplitude modulations in the jet velocity profile giving conditions where jet stability deviates from the usual Rayleigh behaviour. To explore these non-linear effects, we have developed a one-dimensional jetting model. In particular, we identify a modulation range for which pinching occurs upstream of the connecting filament, rather than downstream - a phenomenon we call ``inverted'' break-up. Furthermore, this behaviour can be controlled by the addition of harmonics to the initial driving signal. Our results are compared to full axisymmetric simulations in order to incorporate the effects of nozzle geometry. EPSRC Innovation in Industrial Technology.

  12. Blocked inverted indices for exact clustering of large chemical spaces.

    PubMed

    Thiel, Philipp; Sach-Peltason, Lisa; Ottmann, Christian; Kohlbacher, Oliver

    2014-09-22

    The calculation of pairwise compound similarities based on fingerprints is one of the fundamental tasks in chemoinformatics. Methods for efficient calculation of compound similarities are of the utmost importance for various applications like similarity searching or library clustering. With the increasing size of public compound databases, exact clustering of these databases is desirable, but often computationally prohibitively expensive. We present an optimized inverted index algorithm for the calculation of all pairwise similarities on 2D fingerprints of a given data set. In contrast to other algorithms, it neither requires GPU computing nor yields a stochastic approximation of the clustering. The algorithm has been designed to work well with multicore architectures and shows excellent parallel speedup. As an application example of this algorithm, we implemented a deterministic clustering application, which has been designed to decompose virtual libraries comprising tens of millions of compounds in a short time on current hardware. Our results show that our implementation achieves more than 400 million Tanimoto similarity calculations per second on a common desktop CPU. Deterministic clustering of the available chemical space thus can be done on modern multicore machines within a few days. PMID:25136755

  13. Inverted-U function relating cortical plasticity and task difficulty.

    PubMed

    Engineer, N D; Engineer, C T; Reed, A C; Pandya, P K; Jakkamsetti, V; Moucha, R; Kilgard, M P

    2012-03-15

    Many psychological and physiological studies with simple stimuli have suggested that perceptual learning specifically enhances the response of primary sensory cortex to task-relevant stimuli. The aim of this study was to determine whether auditory discrimination training on complex tasks enhances primary auditory cortex responses to a target sequence relative to non-target and novel sequences. We collected responses from more than 2000 sites in 31 rats trained on one of six discrimination tasks that differed primarily in the similarity of the target and distractor sequences. Unlike training with simple stimuli, long-term training with complex stimuli did not generate target-specific enhancement in any of the groups. Instead, cortical receptive field size decreased, latency decreased, and paired pulse depression decreased in rats trained on the tasks of intermediate difficulty, whereas tasks that were too easy or too difficult either did not alter or degraded cortical responses. These results suggest an inverted-U function relating neural plasticity and task difficulty.

  14. Inverted-U Function Relating Cortical Plasticity and Task Difficulty

    PubMed Central

    Engineer, Navzer D.; Engineer, Crystal T.; Reed, Amanda C.; Pandya, Pritesh K.; Jakkamsetti, Vikram; Moucha, Raluca; Kilgard, Michael P.

    2012-01-01

    Many psychological and physiological studies with simple stimuli have suggested that perceptual learning specifically enhances the response of primary sensory cortex to task-relevant stimuli. The aim of this study was to determine whether auditory discrimination training on complex tasks enhances primary auditory cortex responses to a target sequence relative to non-target and novel sequences. We collected responses from more than 2,000 sites in 31 rats trained on one of six discrimination tasks that differed primarily in the similarity of the target and distractor sequences. Unlike training with simple stimuli, long-term training with complex stimuli did not generate target specific enhancement in any of the groups. Instead, cortical receptive field size decreased, latency decreased, and paired pulse depression decreased in rats trained on the tasks of intermediate difficulty while tasks that were too easy or too difficult either did not alter or degraded cortical responses. These results suggest an inverted-U function relating neural plasticity and task difficulty. PMID:22249158

  15. Stable adaptive fuzzy controllers with application to inverted pendulum tracking.

    PubMed

    Wang, L X

    1996-01-01

    An adaptive fuzzy controller is constructed from a set of fuzzy IF-THEN rules whose parameters are adjusted on-line according to some adaptation law for the purpose of controlling the plant to track a given-trajectory. In this paper, two adaptive fuzzy controllers are designed based on the Lyapunov synthesis approach. We require that the final closed-loop system must be globally stable in the sense that all signals involved (states, controls, parameters, etc.) must be uniformly bounded. Roughly speaking, the adaptive fuzzy controllers are designed through the following steps: first, construct an initial controller based on linguistic descriptions (in the form of fuzzy IF-THEN rules) about the unknown plant from human experts; then, develop an adaptation law to adjust the parameters of the fuzzy controller on-line. We prove, for both adaptive fuzzy controllers, that: (1) all signals in the closed-loop systems are uniformly bounded; and (2) the tracking errors converge to zero under mild conditions. We provide the specific formulas of the bounds so that controller designers can determine the bounds based on their requirements. Finally, the adaptive fuzzy controllers are used to control the inverted pendulum to track a given trajectory, and the simulation results show that: (1) the adaptive fuzzy controllers can perform successful tracking without using any linguistic information; and (2) after incorporating some linguistic fuzzy rules into the controllers, the adaptation speed becomes faster and the tracking error becomes smaller.

  16. 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.

  17. 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

  18. 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.

  19. 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

  20. 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.

  1. Efficient inverted polymer solar cells based on conjugated polyelectrolyte and zinc oxide modified ITO electrode

    SciTech Connect

    Yuan, Tao; Zhu, Xiaoguang; Tu, Guoli; Zhou, Lingyu; Zhang, Jian

    2015-02-23

    Efficient inverted polymer solar cells (PSCs) were constructed by utilizing a conjugated polyelectrolyte PF{sub EO}SO{sub 3}Na and zinc oxide to modify the indium tin oxide (ITO) electrode. The ITO electrode modified by PF{sub EO}SO{sub 3}Na and zinc oxide possesses high transparency, increased electron mobility, smoothened surface, and lower work function. PTB7:PC{sub 71}BM inverted PSCs containing the modified ITO electrode achieved a high power conversion efficiency (PCE) of 8.49%, exceeding that of the control device containing a ZnO modified ITO electrode (7.48%). Especially, PCE-10:PC{sub 71}BM inverted polymer solar cells achieved a high PCE up to 9.4%. These results demonstrate a useful approach to improve the performance of inverted polymer solar cells.

  2. INVERTING CASCADE IMPACTOR DATA FOR SIZE-RESOLVED CHARACTERIZATION OF FINE PARTICULATE SOURCE EMISSIONS

    EPA Science Inventory

    Cascade impactors are particularly useful in determining the mass size distributions of particulate and individual chemical species. The impactor raw data must be inverted to reconstruct a continuous particle size distribution. An inversion method using a lognormal function for p...

  3. Inverted Metamorphic Cell Development: Cooperative Research and Development Final Report, CRADA Number CRD-05-156

    SciTech Connect

    Wanlass, M.

    2012-05-01

    This CRADA targeted technology transfer of the inverted metamorphic multi-junction (IMM) solar cell innovation from NREL to Emcore Photovoltaics. The technology transfer was successfully completed. Additionally, NREL provided materials characterization of solar cell structures produced at Emcore.

  4. Beta Test Plan for Advanced Inverters Interconnecting Distributed Resources with Electric Power Systems

    SciTech Connect

    Hoke, A.; Chakraborty, S.; Basso, T.; Coddington, M.

    2014-01-01

    This document provides a preliminary (beta) test plan for grid interconnection systems of advanced inverter-based DERs. It follows the format and methodology/approach established by IEEE Std 1547.1, while incorporating: 1. Upgraded tests for responses to abnormal voltage and frequency, and also including ride-through. 2. A newly developed test for voltage regulation, including dynamic response testing. 3. Modified tests for unintentional islanding, open phase, and harmonics to include testing with the advanced voltage and frequency response functions enabled. Two advanced inverters, one single-phase and one three-phase, were tested under the beta test plan. These tests confirmed the importance of including tests for inverter dynamic response, which varies widely from one inverter to the next.

  5. Commercialization of a 2.5kW Utility Interactive Inverter for Distributed Generation

    SciTech Connect

    Torrey, David A.

    2006-05-26

    Through this project, Advanced Energy Conversion (AEC) has developed, tested, refined and is preparing to commercialize a 2.5kW utility-interactive inverter system for distributed generation. The inverter technology embodies zero-voltage switching technology that will ultimately yield a system that is smaller, less expensive and more efficient than existing commercial technologies. This program has focused on commercial success through careful synthesis of technology, market-focus and business development. AEC was the primary participant. AEC is utilizing contract manufacturers in the early stages of production, allowing its technical staff to focus on quality control issues and product enhancements. The objective of this project was to bring the AEC inverter technology from its current pre-production state to a commercial product. Federal funds have been used to build and test production-intent inverters, support the implementation of the commercialization plan and bring the product to the point of UL certification.

  6. Correction of mandibular deficiency by inverted-L osteotomy of ramus and iliac crest bone grafting

    PubMed Central

    Zhu, Song-Song; Feng, Ge; Li, Ji-Hua; Luo, En; Hu, Jing

    2012-01-01

    This study was to describe the use of inverted-L osteotomy of ramus and iliac bone graft for the management of mandibular deficiency in adult patients. From 2008 to 2010, 11 patients (aged 19 to 29 years) with mandibular deficiency underwent intraoral or extraoral inverted-L osteotomy of ramus and iliac crest bone grafting. Data were collected from the patients' records, photographs and radiographs. The height and width of the ramus were successfully expanded by inverted-L osteotomy and iliac crest bone grafting with minimal complications in all patients, resulting in significant improvement in occlusion and facial appearance. Our early results showed that the inverted-L osteotomy of ramus and iliac crest bone grafting is safe and effective, and should be considered as a good alternative for the patients with mandibular deficiency. PMID:23258379

  7. Development and performance of pulse-width-modulated static inverter and converter modules

    NASA Technical Reports Server (NTRS)

    Pittman, P. F.; Gourash, F.; Birchenough, A. G.; Pittman, P. F.; Ravas, R. J.; Hall, W. G.

    1971-01-01

    Pulse-width-modulated inverter and converter modules are being developed for modular aerospace electrical power systems. The modules, rate 2.5 kilowatts per module and 10-minute - 150-percent overload, operate from 56 volts dc. The converter module provides two output voltages: a nominal link voltage of 200 volts dc when used with the inverter, and 150 volts dc to a load bus when used separately. The inverter module output is 400-hertz, sinusoidal, three-phase, 120/208 volts. Tests of breadboard models with standard parts and integrated circuits show rated power efficiencies of 71.4 and 85.1 percent and voltage regulation of 5 and 3.1 percent for inverter and converter modules, respectively. Sine-wave output distortion is 0.74 percent.

  8. Dynamic characteristic prediction of inverted pendulum under the reduced-gravity space environments

    NASA Astrophysics Data System (ADS)

    Li, Guohui; Liu, Xue

    2010-09-01

    A new multi-local linear model based on the Tkakgi-Sugeno approach is presented to carry out controlling of a nonlinear unsteady system and to make a design of inverted pendulum fuzzy controller. Nonlinear multi-variance behaviors are transformed to a multi-local linear model using a fuzzy approximation method, which is used to implement control steadily and rapidly for the global system. Detailed investigations on dynamic behaviors of inverted pendulum under reduced-gravity space environments are performed using Simulink simulations. Results showed that stabilization of an inverted pendulum is greatly affected by reduced-gravity conditions and effects of θ angle variation are the largest. When θ is greater than 1.571 rad threshold value, balances will be lost under earth, lunar and microgravity conditions. Furthermore, microgravity is favorable for keeping balance status. An appropriate compensation controlling provided by the presented fuzzy controller can keep a better balance for inverted pendulum.

  9. Performance Comparison Between Lqr and Pid Controllers for AN Inverted Pendulum System

    NASA Astrophysics Data System (ADS)

    Nasir, A. N. K.; Ahmad, M. A.; Rahmat, M. F.

    2008-10-01

    The objective of this paper is to compare the time specification performance between two conventional controllers for an inverted pendulum system. The goal is to determine which control strategy delivers better performance with respect to pendulum's angle and cart's position. The inverted pendulum represents a challenging control problem, which continually moves toward an uncontrolled state. Two controllers are presented such as Linear-Quadratic-Regulator (LQR) and Proportional-Integral-Derivatives (PID) controllers for controlling the linearized system of inverted pendulum model. Simulation study has been done in Matlab simulink environment shows that both controllers are capable to control multi output inverted pendulum system successfully. The result shows that LQR produced better response compared to PID control strategies and is presented in time domain.

  10. Recent advances in stacked inverted top-emitting organic electrophosphorescent diodes (presentation video)

    NASA Astrophysics Data System (ADS)

    Kippelen, Bernard; Knauer, Keith A.; Najafabadi, Ehsan M.; Zhou, Yinhua; Fuentes-Hernandez, Canek

    2014-10-01

    In this talk, we will discuss recent advances in green and white electrophosphorescent stacked organic light-emitting diodes (OLEDs) with inverted top-emitting structures. These devices combine the advantages of having inverted electrode positions, a top-emissive design, and a stacked architecture. We will also demonstrate OLEDs that are fabricated on cellulose nanocrystal substrates and discuss how the use of such naturally-derived materials can reduce the environmental footprint of organic electronic devices such as OLEDs.

  11. Quality improvement of the AC electrical energy produced by a modular inverter dedicated to photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Ternifi, T. Z.; Atik, L.; Bachir, G.; Belarbi, A. W.; Petit, P.; Aillerie, M.

    2016-07-01

    This paper presents a parallel topology of a modular photovoltaic inverter, allowing a marked improvement in the quality of the output energy signal. This is a feature of much interest in practical applications as it will produce an output signal with very low harmonic distortions. In this contribution, we describe the inverter, then the bipolar pulse width modulation (PWM) strategy, which will bevalidateby simulation. Finally, some experimental results are exposed to illustrate our work.

  12. Analysis and performance of paralleling circuits for modular inverter-converter systems

    NASA Technical Reports Server (NTRS)

    Birchenough, A. G.; Gourash, F.

    1972-01-01

    As part of a modular inverter-converter development program, control techniques were developed to provide load sharing among paralleled inverters or converters. An analysis of the requirements of paralleling circuits and a discussion of the circuits developed and their performance are included in this report. The current sharing was within 5.6 percent of rated-load current for the ac modules and 7.4 percent for the dc modules for an initial output voltage unbalance of 5 volts.

  13. Rate analysis for a hybrid quantum repeater

    SciTech Connect

    Bernardes, Nadja K.; Loock, Peter van

    2011-01-15

    We present a detailed rate analysis for a hybrid quantum repeater assuming perfect memories and using optimal probabilistic entanglement generation and deterministic swapping routines. The hybrid quantum repeater protocol is based on atomic qubit-entanglement distribution through optical coherent-state communication. An exact, analytical formula for the rates of entanglement generation in quantum repeaters is derived, including a study on the impacts of entanglement purification and multiplexing strategies. More specifically, we consider scenarios with as little purification as possible and we show that for sufficiently low local losses, such purifications are still more powerful than multiplexing. In a possible experimental scenario, our hybrid system can create near-maximally entangled (F=0.98) pairs over a distance of 1280 km at rates of the order of 100 Hz.

  14. Do gamma-ray burst sources repeat?

    NASA Technical Reports Server (NTRS)

    Meegan, Charles A.; Hartmann, Dieter H.; Brainerd, J. J.; Briggs, Michael S.; Paciesas, William S.; Pendleton, Geoffrey; Kouveliotou, Chryssa; Fishman, Gerald; Blumenthal, George; Brock, Martin

    1995-01-01

    The demonstration of repeated gamma-ray bursts from an individual source would severely constrain burst source models. Recent reports (Quashnock and Lamb, 1993; Wang and Lingenfelter, 1993) 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 and 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 observed bursts cannot be excluded.

  15. Protonation process of conjugated polyelectrolytes on enhanced power conversion efficiency in the inverted polymer solar cells

    NASA Astrophysics Data System (ADS)

    Yi, Chao; Hu, Rong; Ren, He; Hu, Xiaowen; Wang, Shu; Gong, Xiong; Cao, Yong

    2014-01-01

    In this study, two conjugated polyelectrolytes, polythiophene derivative (PTP) and poly[(9,9-bis [6‧-N, N, N-trimethylammonium] hexyl)-fluorenylene-phenylene] dibromide (PFP), are utilized to modify the surface properties of ZnO electron extraction layer (EEL) in the inverted polymer solar cells (PSCs). Both higher short-circuit current densities and larger open-circuit voltages were observed from the inverted PSCs with ZnO/PFP or ZnO/PTP as compared with those only with ZnO EEL. The protonation process for PTP and PFP in solution is distinguished. Overall, more than 40% enhanced power conversion efficiency (PCE) from the inverted PSCs with ZnO/PFP, in which the PFP could be fully ionized in deionized water, and more than 30% enhanced PCE from the inverted PSCs with ZnO/PTP, as the case that the PTP could not be fully ionized in deionized water, as compared with the inverted PSCs with ZnO EEL were observed, respectively. These results demonstrate that the conjugated polyelectrolytes play an important role in enhancement of device performance of inverted PSCs and that the protonation process of the conjugated polyelectrolytes is critical to the modification for EEL in PSCs.

  16. Experimental Evaluation of Load Rejection Over-Voltage from Grid-Tied Solar Inverters

    SciTech Connect

    Nelson, Austin; Hoke, Anderson; Chakraborty, Sudipta; Ropp, Michael; Chebahtah, Justin; Wang, Trudie; Zimmerly, Brian

    2015-06-14

    This paper investigates the impact of load rejection over-voltage (LRO) from commercially available grid-tied photovoltaic (PV) inverters. LRO can occur when a breaker opens and the power output from a distributed energy resource (DER) exceeds the load. Simplified models of current-controlled inverters can over-predict LRO magnitudes, thus it is useful to quantify the effect through laboratory testing. The load rejection event was replicated using a hardware testbed at the National Renewable Energy Laboratory (NREL), and a set of commercially available PV inverters was tested to quantify the impact of LRO for a range of generation-to-load ratios. The magnitude and duration of the over-voltage events are reported in this paper along with a discussion of characteristic inverter output behavior. The results for the inverters under test showed that maximum over-voltage magnitudes were less than 200% of nominal voltage, and much lower in many test cases. These research results are important because utilities that interconnect inverter-based DER need to understand their characteristics under abnormal grid conditions.

  17. High-Performance Inverted Organic Photovoltaics Without Hole-Selective Contact

    PubMed Central

    2015-01-01

    A detailed investigation of the functionality of inverted organic photovoltaics (OPVs) using bare Ag contacts as the top electrode is presented. The inverted OPVs without a hole-transporting layer (HTL) exhibit a significant gain in hole-carrier selectivity and power-conversion efficiency (PCE) after exposure in ambient conditions. Inverted OPVs comprised of ITO–ZnO–poly(3-hexylthiophene-2,5-diyl)/phenyl-C61-butyric acid methyl ester (P3HT/PCBM)–Ag demonstrate over 3.5% power conversion efficiency only if the devices are exposed in air for over 4 days. As concluded through a series of measurements, the oxygen presence is essential to obtaining fully operational solar cell devices without HTL. Moreover, accelerated stability tests under damp heat conditions (RH = 85% and T = 65 °C) performed to nonencapsulated OPVs demonstrate that HTL-free inverted OPVs exhibit comparable stability to the reference inverted OPVs. Importantly, it is shown that bare Ag top electrodes can be efficiently used in inverted OPVs using various high-performance polymer–fullerene bulk heterojunction material systems demonstrating 6.5% power-conversion efficiencies. PMID:26468993

  18. High-Performance Inverted Organic Photovoltaics Without Hole-Selective Contact.

    PubMed

    Savva, Achilleas; Burgués-Ceballos, Ignasi; Papazoglou, Giannis; Choulis, Stelios A

    2015-11-11

    A detailed investigation of the functionality of inverted organic photovoltaics (OPVs) using bare Ag contacts as the top electrode is presented. The inverted OPVs without a hole-transporting layer (HTL) exhibit a significant gain in hole-carrier selectivity and power-conversion efficiency (PCE) after exposure in ambient conditions. Inverted OPVs comprised of ITO-ZnO-poly(3-hexylthiophene-2,5-diyl)/phenyl-C61-butyric acid methyl ester (P3HT/PCBM)-Ag demonstrate over 3.5% power conversion efficiency only if the devices are exposed in air for over 4 days. As concluded through a series of measurements, the oxygen presence is essential to obtaining fully operational solar cell devices without HTL. Moreover, accelerated stability tests under damp heat conditions (RH = 85% and T = 65 °C) performed to nonencapsulated OPVs demonstrate that HTL-free inverted OPVs exhibit comparable stability to the reference inverted OPVs. Importantly, it is shown that bare Ag top electrodes can be efficiently used in inverted OPVs using various high-performance polymer-fullerene bulk heterojunction material systems demonstrating 6.5% power-conversion efficiencies.

  19. Invert emulsion: Method of preparation and application as proper formulation of entomopathogenic fungi

    PubMed Central

    Batta, Yacoub A.

    2016-01-01

    The present article describes the technique used for preparing the invert emulsion (water-in-oil type) then, selecting the most proper formulation of invert emulsion for being used as a carrier formulation of entomopathogenic fungi. It also describes the method used for testing the efficacy of the formulated fungi as biocontrol agents of targeted insects. Detailed examples demonstrating the efficacy of formulated strains of entomopathogenic fungi against certain species of insect pests were included in the present article. The techniques and methods described in this article are reproducible and helpful in enhancing the effectiveness of formulated fungi against wide range of targeted insects in comparison with the unformulated form of these fungi. Also, these techniques and methods can be used effectively in crop protection and in the integrated pest management programs. Finally, it is important to indicate that the ingredients used for preparation of the invert emulsion have no environmental side-effects or health risks since these ingredients are safe to use and can be used in manufacturing of cosmetics or as food additives.•Description of method used for preparation of invert emulsion (water-in-oil type) and selecting the most stable and non-viscous emulsion.•Description of technique used for introducing the entomopathogenic fungi into the selected stable and non-viscous invert emulsion.•Description of method for testing the efficacy of introduced entomopathogenic fungus into the selected invert emulsion against targeted insects with detailed examples on the efficacy testing. PMID:26981435

  20. Resonant snubber based soft-switching inverters for electric propulsion drives

    SciTech Connect

    Lai, J.S.

    1996-05-01

    This paper summarizes recently developed soft-switching inverters and proposes two alternative options for electric propulsion drives. The newly developed soft-switching inverter employs an auxiliary switch and a resonant inductor per phase to produce a zero voltage across the main switch so that the main switch can turn on at the zero-voltage condition. Both the auxiliary switch and the resonant inductor are operating at a fractional duty, and thus are small in size as compared to the main inverter circuit components. Operation modes in a complete zero-voltage switching cycle for the single-phase soft-switching inverter are described in detail with graphical explanations. The circuit operation was first verified by a computer simulation and then tested with an 1-kW single-phase and an 100-kW three-phase inverters. Experimental results are presented to show the superior performance in efficiency improvement, EMI reduction, and dv/dt reduction of the proposed soft-switching inverters.