Effect of intermediate annealing on the microstructure and mechanical property of ZK60 magnesium alloy produced by twin roll casting and hot rolling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Hongmei, E-mail: hmchen@just.edu.cn; Zang, Qianhao; Yu, Hui

2015-08-15

Twin roll cast (designated as TRC in short) ZK60 magnesium alloy strip with 3.5 mm thickness was used in this paper. The TRC ZK60 strip was multi-pass rolled at different temperatures, intermediate annealing heat treatment was performed when the thickness of the strip changed from 3.5 mm to 1 mm, and then continued to be rolled until the thickness reached to 0.5 mm. The effect of intermediate annealing during rolling process on microstructure, texture and room temperature mechanical properties of TRC ZK60 strip was studied by using OM, TEM, XRD and electronic universal testing machine. The introduction of intermediate annealingmore » can contribute to recrystallization in the ZK60 sheet which was greatly deformed, and help to reduce the stress concentration generated in the rolling process. Microstructure uniformity and mechanical properties of the ZK60 alloy sheet were also improved; in particular, the room temperature elongation was greatly improved. When the TRC ZK60 strip was rolled at 300 °C and 350 °C, the room temperature elongation of the rolled sheet with 0.5 mm thickness which was intermediate annealed during the rolling process was increased by 95% and 72% than that of no intermediate annealing, respectively. - Highlights: • Intermediate annealing was introduced during hot rolling process of twin roll cast ZK60 alloy. • Intermediate annealing can contribute to recrystallization and reduce the stress concentration in the deformed ZK60 sheet. • Microstructure uniformity and mechanical properties of the ZK60 sheet were improved, in particular, the room temperature elongation. • The elongation of the rolled ZK60 sheet after intermediate annealed was increased by 95% and 72% than that of no intermediate annealing.« less

Circular RNAs: diversity of form and function.

PubMed

Lasda, Erika; Parker, Roy

2014-12-01

It is now clear that there is a diversity of circular RNAs in biological systems. Circular RNAs can be produced by the direct ligation of 5' and 3' ends of linear RNAs, as intermediates in RNA processing reactions, or by "backsplicing," wherein a downstream 5' splice site (splice donor) is joined to an upstream 3' splice site (splice acceptor). Circular RNAs have unique properties including the potential for rolling circle amplification of RNA, the ability to rearrange the order of genomic information, protection from exonucleases, and constraints on RNA folding. Circular RNAs can function as templates for viroid and viral replication, as intermediates in RNA processing reactions, as regulators of transcription in cis, as snoRNAs, and as miRNA sponges. Herein, we review the breadth of circular RNAs, their biogenesis and metabolism, and their known and anticipated functions. © 2014 Lasda and Parker; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

Circular RNAs: diversity of form and function

PubMed Central

Lasda, Erika

2014-01-01

It is now clear that there is a diversity of circular RNAs in biological systems. Circular RNAs can be produced by the direct ligation of 5′ and 3′ ends of linear RNAs, as intermediates in RNA processing reactions, or by “backsplicing,” wherein a downstream 5′ splice site (splice donor) is joined to an upstream 3′ splice site (splice acceptor). Circular RNAs have unique properties including the potential for rolling circle amplification of RNA, the ability to rearrange the order of genomic information, protection from exonucleases, and constraints on RNA folding. Circular RNAs can function as templates for viroid and viral replication, as intermediates in RNA processing reactions, as regulators of transcription in cis, as snoRNAs, and as miRNA sponges. Herein, we review the breadth of circular RNAs, their biogenesis and metabolism, and their known and anticipated functions. PMID:25404635

A DNA logic gate based on strand displacement reaction and rolling circle amplification, responding to multiple low-abundance DNA fragment input signals, and its application in detecting miRNAs.

PubMed

Chen, Yuqi; Song, Yanyan; Wu, Fan; Liu, Wenting; Fu, Boshi; Feng, Bingkun; Zhou, Xiang

2015-04-25

A conveniently amplified DNA AND logic gate platform was designed for the highly sensitive detection of low-abundance DNA fragment inputs based on strand displacement reaction and rolling circle amplification strategy. Compared with others, this system can detect miRNAs in biological samples. The success of this strategy demonstrates the potential of DNA logic gates in disease diagnosis.

Dual channel sensitive detection of hsa-miR-21 based on rolling circle amplification and quantum dots tagging.

PubMed

Wangt, Dan-Chen; Hu, Li-Hui; Zhou, Yu-Hui; Huang, Yu-Ting; Li, Xinhua; Zhu, Jun-Jie

2014-04-01

An isothermal, highly sensitive and specific assay for the detection of hsa-miR-21 with the integration of QDs tagging and rolling circle amplification was offered. In addition, a dual channel strategy for miRNA detection was proposed: anodic stripping voltammetry (ASV) and fluorescent method were both performed for the final Cd2+ signal readout. The designed strategy exhibited good specificity to hsa-miR-21 and presented comparable detection results by detection methods.

Unveiling the mystery of mitochondrial DNA replication in yeasts.

PubMed

Chen, Xin Jie; Clark-Walker, George Desmond

2018-01-01

Conventional DNA replication is initiated from specific origins and requires the synthesis of RNA primers for both the leading and lagging strands. In contrast, the replication of yeast mitochondrial DNA is origin-independent. The replication of the leading strand is likely primed by recombinational structures and proceeded by a rolling circle mechanism. The coexistent linear and circular DNA conformers facilitate the recombination-based initiation. The replication of the lagging strand is poorly understood. Re-evaluation of published data suggests that the rolling circle may also provide structures for the synthesis of the lagging-strand by mechanisms such as template switching. Thus, the coupling of recombination with rolling circle replication and possibly, template switching, may have been selected as an economic replication mode to accommodate the reductive evolution of mitochondria. Such a replication mode spares the need for conventional replicative components, including those required for origin recognition/remodelling, RNA primer synthesis and lagging-strand processing. Copyright © 2017 Elsevier B.V. and Mitochondria Research Society. All rights reserved.

A method for the determination of the coefficient of rolling friction using cycloidal pendulum

NASA Astrophysics Data System (ADS)

Ciornei, M. C.; Alaci, S.; Ciornei, F. C.; Romanu, I. C.

2017-08-01

The paper presents a method for experimental finding of coefficient of rolling friction appropriate for biomedical applications based on the theory of cycloidal pendulum. When a mobile circle rolls over a fixed straight line, the points from the circle describe trajectories called normal cycloids. To materialize this model, it is sufficient that a small region from boundary surfaces of a moving rigid body is spherical. Assuming pure rolling motion, the equation of motion of the cycloidal pendulum is obtained - an ordinary nonlinear differential equation. The experimental device is composed by two interconnected balls rolling over the material to be studied. The inertial characteristics of the pendulum can be adjusted via weights placed on a rod. A laser spot oscillates together to the pendulum and provides the amplitude of oscillations. After finding the experimental parameters necessary in differential equation of motion, it can be integrated using the Runge-Kutta of fourth order method. The equation was integrated for several materials and found values of rolling friction coefficients. Two main conclusions are drawn: the coefficient of rolling friction influenced significantly the amplitude of oscillation but the effect upon the period of oscillation is practically imperceptible. A methodology is proposed for finding the rolling friction coefficient and the pure rolling condition is verified.

Rolling Reloaded

ERIC Educational Resources Information Center

Jones, Simon A.; Nieminen, John M.

2008-01-01

Not so long ago a new observation about rolling motion was described: for a rolling wheel, there is a set of points with instantaneous velocities directed at or away from the centre of the wheel; these points form a circle whose diameter connects the centre of the wheel to the wheel's point of contact with the ground (Sharma 1996 "Eur. J. Phys."…

NanoCluster Beacons as reporter probes in rolling circle enhanced enzyme activity detection

NASA Astrophysics Data System (ADS)

Juul, Sissel; Obliosca, Judy M.; Liu, Cong; Liu, Yen-Liang; Chen, Yu-An; Imphean, Darren M.; Knudsen, Birgitta R.; Ho, Yi-Ping; Leong, Kam W.; Yeh, Hsin-Chih

2015-04-01

As a newly developed assay for the detection of endogenous enzyme activity at the single-catalytic-event level, Rolling Circle Enhanced Enzyme Activity Detection (REEAD) has been used to measure enzyme activity in both single human cells and malaria-causing parasites, Plasmodium sp. Current REEAD assays rely on organic dye-tagged linear DNA probes to report the rolling circle amplification products (RCPs), the cost of which may hinder the widespread use of REEAD. Here we show that a new class of activatable probes, NanoCluster Beacons (NCBs), can simplify the REEAD assays. Easily prepared without any need for purification and capable of large fluorescence enhancement upon hybridization, NCBs are cost-effective and sensitive. Compared to conventional fluorescent probes, NCBs are also more photostable. As demonstrated in reporting the human topoisomerases I (hTopI) cleavage-ligation reaction, the proposed NCBs suggest a read-out format attractive for future REEAD-based diagnostics.As a newly developed assay for the detection of endogenous enzyme activity at the single-catalytic-event level, Rolling Circle Enhanced Enzyme Activity Detection (REEAD) has been used to measure enzyme activity in both single human cells and malaria-causing parasites, Plasmodium sp. Current REEAD assays rely on organic dye-tagged linear DNA probes to report the rolling circle amplification products (RCPs), the cost of which may hinder the widespread use of REEAD. Here we show that a new class of activatable probes, NanoCluster Beacons (NCBs), can simplify the REEAD assays. Easily prepared without any need for purification and capable of large fluorescence enhancement upon hybridization, NCBs are cost-effective and sensitive. Compared to conventional fluorescent probes, NCBs are also more photostable. As demonstrated in reporting the human topoisomerases I (hTopI) cleavage-ligation reaction, the proposed NCBs suggest a read-out format attractive for future REEAD-based diagnostics. Electronic supplementary information (ESI) available: The detailed steps of NCB preparation, REEAD assay and STEM imaging. The sequences of the sNCB and the REEAD substrate. See DOI: 10.1039/c5nr01705j

To Believe the Past or to Trust the Future

ERIC Educational Resources Information Center

Jin, Fengtao; Zhou, Zhaoyan

2012-01-01

A small ball rolls down from a quarter-circle to a frictionless plane. What will be the magnitude of the normal force when the ball arrives at the tangent point of the circle and the plane? According to the centripetal force formula, the normal force will be 3 "mg" when the curvature radius of the circle is considered, but will be "mg" instead…

Signal amplification of padlock probes by rolling circle replication.

PubMed Central

Banér, J; Nilsson, M; Mendel-Hartvig, M; Landegren, U

1998-01-01

Circularizing oligonucleotide probes (padlock probes) have the potential to detect sets of gene sequences with high specificity and excellent selectivity for sequence variants, but sensitivity of detection has been limiting. By using a rolling circle replication (RCR) mechanism, circularized but not unreacted probes can yield a powerful signal amplification. We demonstrate here that in order for the reaction to proceed efficiently, the probes must be released from the topological link that forms with target molecules upon hybridization and ligation. If the target strand has a nearby free 3' end, then the probe-target hybrids can be displaced by the polymerase used for replication. The displaced probe can then slip off the targetstrand and a rolling circle amplification is initiated. Alternatively, the target sequence itself can prime an RCR after its non-base paired 3' end has been removed by exonucleolytic activity. We found the Phi29 DNA polymerase to be superior to the Klenow fragment in displacing the target DNA strand, and it maintained the polymerization reaction for at least 12 h, yielding an extension product that represents several thousand-fold the length of the padlock probe. PMID:9801302

Yoctomole electrochemical genosensing of Ebola virus cDNA by rolling circle and circle to circle amplification.

PubMed

Carinelli, S; Kühnemund, M; Nilsson, M; Pividori, M I

2017-07-15

This work addresses the design of an Ebola diagnostic test involving a simple, rapid, specific and highly sensitive procedure based on isothermal amplification on magnetic particles with electrochemical readout. Ebola padlock probes were designed to detect a specific L-gene sequence present in the five most common Ebola species. Ebola cDNA was amplified by rolling circle amplification (RCA) on magnetic particles. Further re-amplification was performed by circle-to-circle amplification (C2CA) and the products were detected in a double-tagging approach using a biotinylated capture probe for immobilization on magnetic particles and a readout probe for electrochemical detection by square-wave voltammetry on commercial screen-printed electrodes. The electrochemical genosensor was able to detect as low as 200 ymol, corresponding to 120 cDNA molecules of L-gene Ebola virus with a limit of detection of 33 cDNA molecules. The isothermal double-amplification procedure by C2CA combined with the electrochemical readout and the magnetic actuation enables the high sensitivity, resulting in a rapid, inexpensive, robust and user-friendly sensing strategy that offers a promising approach for the primary care in low resource settings, especially in less developed countries. Copyright © 2016 Elsevier B.V. All rights reserved.

Quantifying the benefits of improved rolling of chip seals : final report, June 2008.

DOT National Transportation Integrated Search

2008-06-01

This report presents an improvement in the rolling protocol for chip seals based on an evaluation of aggregate : retention performance and aggregate embedment depth. The flip-over test (FOT), Vialit test, modified sand circle : test, digital image pr...

Digital Storytelling: Reinventing Literature Circles

ERIC Educational Resources Information Center

Tobin, Maryann Tatum

2012-01-01

New literacies in reading research demand the study of comprehension skills using multiple modalities through a more complex, multi-platform view of reading. Taking into account the robust roll of technology in our daily lives, this article presents an update to the traditional literature circle lesson to include digital storytelling and…

Investigation of the Influence of Shapes-Texture on Surface Deformation of UHMWPE as a Bearing Material in Static Normal Load and Rolling Contact

NASA Astrophysics Data System (ADS)

Lestari, W. D.; Ismail, R.; Jamari, J.; Bayuseno, A. P.

2017-05-01

Surface texture is a common method for improving wear properties of a tribo-pair of soft and hard bearing material. The reduction of wear rates on the contacting surface material is becoming important issues. In the present study, analysis of the contact pressure on the flat surface of UHMWPE (Ultra High Molecular Weight Polyethylene) under the static- and rolling motion with the surface of steel ball used the 3D finite element method (FEM) (the ABAQUS software version 6.12). Five shaped-texture models (square, circle, ellipse, triangle, and chevron) were presented on the flat surface for analysis. The normal load of 17, 30 and 50 N was deliberately set-up for static and rolling contact analysis. The contact pressure was determined to predict the wear behavior of the shaped-texture on the flat surface of UHMWPE. The results have shown that the static normal load yielded the lowest von-Mises stress distribution on the shaped-texture of the ellipse for all values applied a load, while the square shape experienced the highest stress distribution. Under rolling contact, however, the increasing load yielded the increasing von Mises stress distribution for the texture with a triangle shape. Moreover, the texture shapes for circle, ellipse, and chevron respectively, may undergo the lowest stress distribution for all load. The wear calculation provided that the circle and square shape may undergo the highest wear rates. Obviously, the surface texture of circle, ellipse, and chevron may experience the lowest wear rates and is potential for use in the surface engineering of bearing materials.

DNA recombination-initiation plays a role in the extremely biased inheritance of yeast [rho-] mitochondrial DNA that contains the replication origin ori5.

PubMed

Ling, Feng; Hori, Akiko; Shibata, Takehiko

2007-02-01

Hypersuppressiveness, as observed in Saccharomyces cerevisiae, is an extremely biased inheritance of a small mitochondrial DNA (mtDNA) fragment that contains a replication origin (HS [rho(-)] mtDNA). Our previous studies showed that concatemers (linear head-to-tail multimers) are obligatory intermediates for mtDNA partitioning and are primarily formed by rolling-circle replication mediated by Mhr1, a protein required for homologous mtDNA recombination. In this study, we found that Mhr1 is required for the hypersuppressiveness of HS [ori5] [rho(-)] mtDNA harboring ori5, one of the replication origins of normal ([rho(+)]) mtDNA. In addition, we detected an Ntg1-stimulated double-strand break at the ori5 locus. Purified Ntg1, a base excision repair enzyme, introduced a double-stranded break by itself into HS [ori5] [rho(-)] mtDNA at ori5 isolated from yeast cells. Both hypersuppressiveness and concatemer formation of HS [ori5] [rho(-)] mtDNA are simultaneously suppressed by the ntg1 null mutation. These results support a model in which, like homologous recombination, rolling-circle HS [ori5] [rho(-)] mtDNA replication is initiated by double-stranded breakage in ori5, followed by Mhr1-mediated homologous pairing of the processed nascent DNA ends with circular mtDNA. The hypersuppressiveness of HS [ori5] [rho(-)] mtDNA depends on a replication advantage furnished by the higher density of ori5 sequences and on a segregation advantage furnished by the higher genome copy number on transmitted concatemers.

Rapid Amplification of Plasmid and Phage DNA Using Phi29 DNA Polymerase and Multiply-Primed Rolling Circle Amplification

PubMed Central

Dean, Frank B.; Nelson, John R.; Giesler, Theresa L.; Lasken, Roger S.

2001-01-01

We describe a simple method of using rolling circle amplification to amplify vector DNA such as M13 or plasmid DNA from single colonies or plaques. Using random primers and φ29 DNA polymerase, circular DNA templates can be amplified 10,000-fold in a few hours. This procedure removes the need for lengthy growth periods and traditional DNA isolation methods. Reaction products can be used directly for DNA sequencing after phosphatase treatment to inactivate unincorporated nucleotides. Amplified products can also be used for in vitro cloning, library construction, and other molecular biology applications. PMID:11381035

Periodic Assembly of Nanospecies on Repetitive DNA Sequences Generated on Gold Nanoparticles by Rolling Circle Amplification

NASA Astrophysics Data System (ADS)

Zhao, Weian; Brook, Michael A.; Li, Yingfu

Periodical assembly of nanospecies is desirable for the construction of nanodevices. We provide a protocol for the preparation of a gold nanoparticle (AuNP)/DNA scaffold on which nanospecies can be assembled in a periodical manner. AuNP/DNA scaffold is prepared by growing long single-stranded DNA (ssDNA) molecules (typically hundreds of nanometers to a few microns in length) on AuNPs via rolling circle amplification (RCA). Since these long ssDNA molecules contain many repetitive sequence units, complementary DNA-attached nanospecies can be assembled through specific hybridization in a controllable and periodical manner.

One-step random mutagenesis by error-prone rolling circle amplification

PubMed Central

Fujii, Ryota; Kitaoka, Motomitsu; Hayashi, Kiyoshi

2004-01-01

In vitro random mutagenesis is a powerful tool for altering properties of enzymes. We describe here a novel random mutagenesis method using rolling circle amplification, named error-prone RCA. This method consists of only one DNA amplification step followed by transformation of the host strain, without treatment with any restriction enzymes or DNA ligases, and results in a randomly mutated plasmid library with 3–4 mutations per kilobase. Specific primers or special equipment, such as a thermal-cycler, are not required. This method permits rapid preparation of randomly mutated plasmid libraries, enabling random mutagenesis to become a more commonly used technique. PMID:15507684

Antigen retrieval, blocking, detection and visualisation systems in immunohistochemistry: a review and practical evaluation of tyramide and rolling circle amplification systems.

PubMed

Warford, Anthony; Akbar, Hameed; Riberio, Deise

2014-11-01

To achieve specificity and sensitivity using immunohistochemistry it is necessary to combine the application of validated primary antibodies with optimised pre-treatment, detection and visualisation steps. The influence of these surrounding procedures is reviewed. A practical evaluation of tyramide signal amplification and rolling circle amplification detection methods is provided in which formalin fixed paraffin embedded sections of adenocarcinomas of breast, colon and lung together with squamous metaplasia of lung were immunostained with CD20 and CK19 primary antibodies. The results indicate that the detection systems are of comparable sensitivity and specificity. Copyright © 2014 Elsevier Inc. All rights reserved.

A microRNA detection system based on padlock probes and rolling circle amplification

PubMed Central

Jonstrup, Søren Peter; Koch, Jørn; Kjems, Jørgen

2006-01-01

The differential expression and the regulatory roles of microRNAs (miRNAs) are being studied intensively these years. Their minute size of only 19–24 nucleotides and strong sequence similarity among related species call for enhanced methods for reliable detection and quantification. Moreover, miRNA expression is generally restricted to a limited number of specific cells within an organism and therefore requires highly sensitive detection methods. Here we present a simple and reliable miRNA detection protocol based on padlock probes and rolling circle amplification. It can be performed without specialized equipment and is capable of measuring the content of specific miRNAs in a few nanograms of total RNA. PMID:16888321

A microRNA detection system based on padlock probes and rolling circle amplification.

PubMed

Jonstrup, Søren Peter; Koch, Jørn; Kjems, Jørgen

2006-09-01

The differential expression and the regulatory roles of microRNAs (miRNAs) are being studied intensively these years. Their minute size of only 19-24 nucleotides and strong sequence similarity among related species call for enhanced methods for reliable detection and quantification. Moreover, miRNA expression is generally restricted to a limited number of specific cells within an organism and therefore requires highly sensitive detection methods. Here we present a simple and reliable miRNA detection protocol based on padlock probes and rolling circle amplification. It can be performed without specialized equipment and is capable of measuring the content of specific miRNAs in a few nanograms of total RNA.

An "off-on" electrochemiluminescent biosensor based on DNAzyme-assisted target recycling and rolling circle amplifications for ultrasensitive detection of microRNA.

PubMed

Zhang, Pu; Wu, Xiaoyan; Yuan, Ruo; Chai, Yaqin

2015-03-17

In this study, an off-on switching of a dual amplified electrochemiluminescence (ECL) biosensor based on Pb(2+)-induced DNAzyme-assisted target recycling and rolling circle amplification (RCA) was constructed for microRNA (miRNA) detection. First, the primer probe with assistant probe and miRNA formed Y junction which was cleaved with the addition of Pb(2+) to release miRNA. Subsequently, the released miRNA could initiate the next recycling process, leading to the generation of numerous intermediate DNA sequences (S2). Afterward, bare glassy carbon electrode (GCE) was immersed into HAuCl4 solution to electrodeposit a Au nanoparticle layer (depAu), followed by the assembly of a hairpin probe (HP). Then, dopamine (DA)-modified DNA sequence (S1) was employed to hybridize with HP, which switching off the sensing system. This is the first work that employs DA to quench luminol ECL signal, possessing the biosensor ultralow background signal. Afterward, S2 produced by the target recycling process was loaded onto the prepared electrode to displace S1 and served as an initiator for RCA. With rational design, numerous repeated DNA sequences coupling with hemin to form hemin/G-quadruplex were generated, which could exhibit strongly catalytic toward H2O2, thus amplified the ECL signal and switched the ON state of the sensing system. The liner range for miRNA detection was from 1.0 fM to 100 pM with a low detection limit down to 0.3 fM. Moreover, with the high sensitivity and specificity induced by the dual signal amplification, the proposed miRNA biosensor holds great potential for analysis of other interesting tumor markers.

Singularity of the time-energy uncertainty in adiabatic perturbation and cycloids on a Bloch sphere

PubMed Central

Oh, Sangchul; Hu, Xuedong; Nori, Franco; Kais, Sabre

2016-01-01

Adiabatic perturbation is shown to be singular from the exact solution of a spin-1/2 particle in a uniformly rotating magnetic field. Due to a non-adiabatic effect, its quantum trajectory on a Bloch sphere is a cycloid traced by a circle rolling along an adiabatic path. As the magnetic field rotates more and more slowly, the time-energy uncertainty, proportional to the length of the quantum trajectory, calculated by the exact solution is entirely different from the one obtained by the adiabatic path traced by the instantaneous eigenstate. However, the non-adiabatic Aharonov- Anandan geometric phase, measured by the area enclosed by the exact path, approaches smoothly the adiabatic Berry phase, proportional to the area enclosed by the adiabatic path. The singular limit of the time-energy uncertainty and the regular limit of the geometric phase are associated with the arc length and arc area of the cycloid on a Bloch sphere, respectively. Prolate and curtate cycloids are also traced by different initial states outside and inside of the rolling circle, respectively. The axis trajectory of the rolling circle, parallel to the adiabatic path, is shown to be an example of transitionless driving. The non-adiabatic resonance is visualized by the number of cycloid arcs. PMID:26916031

Genome-Based Genetic Tool Development for Bacillus methanolicus: Theta- and Rolling Circle-Replicating Plasmids for Inducible Gene Expression and Application to Methanol-Based Cadaverine Production.

PubMed

Irla, Marta; Heggeset, Tonje M B; Nærdal, Ingemar; Paul, Lidia; Haugen, Tone; Le, Simone B; Brautaset, Trygve; Wendisch, Volker F

2016-01-01

Bacillus methanolicus is a thermophilic methylotroph able to overproduce amino acids from methanol, a substrate not used for human or animal nutrition. Based on our previous RNA-seq analysis a mannitol inducible promoter and a putative mannitol activator gene mtlR were identified. The mannitol inducible promoter was applied for controlled gene expression using fluorescent reporter proteins and a flow cytometry analysis, and improved by changing the -35 promoter region and by co-expression of the mtlR regulator gene. For independent complementary gene expression control, the heterologous xylose-inducible system from B. megaterium was employed and a two-plasmid gene expression system was developed. Four different replicons for expression vectors were compared with respect to their copy number and stability. As an application example, methanol-based production of cadaverine was shown to be improved from 11.3 to 17.5 g/L when a heterologous lysine decarboxylase gene cadA was expressed from a theta-replicating rather than a rolling-circle replicating vector. The current work on inducible promoter systems and compatible theta- or rolling circle-replicating vectors is an important extension of the poorly developed B. methanolicus genetic toolbox, valuable for genetic engineering and further exploration of this bacterium.

Genome-Based Genetic Tool Development for Bacillus methanolicus: Theta- and Rolling Circle-Replicating Plasmids for Inducible Gene Expression and Application to Methanol-Based Cadaverine Production

PubMed Central

Irla, Marta; Heggeset, Tonje M. B.; Nærdal, Ingemar; Paul, Lidia; Haugen, Tone; Le, Simone B.; Brautaset, Trygve; Wendisch, Volker F.

2016-01-01

Bacillus methanolicus is a thermophilic methylotroph able to overproduce amino acids from methanol, a substrate not used for human or animal nutrition. Based on our previous RNA-seq analysis a mannitol inducible promoter and a putative mannitol activator gene mtlR were identified. The mannitol inducible promoter was applied for controlled gene expression using fluorescent reporter proteins and a flow cytometry analysis, and improved by changing the -35 promoter region and by co-expression of the mtlR regulator gene. For independent complementary gene expression control, the heterologous xylose-inducible system from B. megaterium was employed and a two-plasmid gene expression system was developed. Four different replicons for expression vectors were compared with respect to their copy number and stability. As an application example, methanol-based production of cadaverine was shown to be improved from 11.3 to 17.5 g/L when a heterologous lysine decarboxylase gene cadA was expressed from a theta-replicating rather than a rolling-circle replicating vector. The current work on inducible promoter systems and compatible theta- or rolling circle-replicating vectors is an important extension of the poorly developed B. methanolicus genetic toolbox, valuable for genetic engineering and further exploration of this bacterium. PMID:27713731

Influence of intermediate annealing on abnormal Goss grain growth in the rolled columnar-grained Fe-Ga-Al alloys

NASA Astrophysics Data System (ADS)

Liu, Yangyang; Li, Jiheng; Gao, Xuexu

2017-08-01

Magnetostrictive Fe82Ga4.5Al13.5 sheets with 0.1 at% NbC were prepared from directional solidified alloys with <0 0 1> preferred orientation. The slabs were hot rolled at 650 °C and warm rolled at 500 °C. Then some warm-rolled sheets were annealed intermediately at 850 °C for 5 min but the others not. After that, all the sheets were cold rolled to a final thickness of ∼0.3 mm. The microstructures, the textures and the distributions of second phase particles in the primary recrystallized samples were investigated. With intermediate annealing, the inhomogeneous microstructure was improved remarkably and strong Goss ({1 1 0}<0 0 1>) and γ-fiber (<1 1 1>//normal direction [ND]) textures were produced in the primary recrystallized samples. But, an evident disadvantage in size and quantity was observed for Goss grains in the primary recrystallized sample without intermediate annealing. After a final annealing, the final textures and magnetostrictions of samples with and without intermediate annealing were characterized. For samples without intermediate annealing, abnormal growth of {1 1 3} grains occurred and deteriorated the magnetostriction. In contrast, abnormal Goss grain growth occurred completely in samples with intermediate annealing and led to saturation magnetostriction as high as 156 ppm.

Preparation of Small RNAs Using Rolling Circle Transcription and Site-Specific RNA Disconnection.

PubMed

Wang, Xingyu; Li, Can; Gao, Xiaomeng; Wang, Jing; Liang, Xingguo

2015-01-13

A facile and robust RNA preparation protocol was developed by combining rolling circle transcription (RCT) with RNA cleavage by RNase H. Circular DNA with a complementary sequence was used as the template for promoter-free transcription. With the aid of a 2'-O-methylated DNA, the RCT-generated tandem repeats of the desired RNA sequence were disconnected at the exact end-to-end position to harvest the desired RNA oligomers. Compared with the template DNA, more than 4 × 10(3) times the amount of small RNA products were obtained when modest cleavage was carried out during transcription. Large amounts of RNA oligomers could easily be obtained by simply increasing the reaction volume.

Characterization of a novel close-to-root papillomavirus from a Florida manatee by using multiply primed rolling-circle amplification: Trichechus manatus latirostris papillomavirus type 1.

PubMed

Rector, Annabel; Bossart, Gregory D; Ghim, Shin-Je; Sundberg, John P; Jenson, A Bennett; Van Ranst, Marc

2004-11-01

By using an isothermal multiply primed rolling-circle amplification protocol, the complete genomic DNA of a novel papillomavirus was amplified from a skin lesion biopsy of a Florida manatee (Trichechus manatus latirostris), one of the most endangered marine mammals in United States coastal waters. The nucleotide sequence, genome organization, and phylogenetic position of the Trichechus manatus latirostris papillomavirus type 1 (TmPV-1) were determined. TmPV-1 is the first virus isolated from the order of Sirenia. A phylogenetic analysis shows that TmPV-1 is only distantly related to other papillomavirus sequences, and it appears in our phylogenetic tree as a novel close-to-root papillomavirus genus.

Direct and precise measurement of displacement and velocity of flexible web in roll-to-roll manufacturing systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kang, Dongwoo; Lee, Eonseok; Choi, Young-Man

Interest in the production of printed electronics using a roll-to-roll system has gradually increased due to its low mass-production costs and compatibility with flexible substrate. To improve the accuracy of roll-to-roll manufacturing systems, the movement of the web needs to be measured precisely in advance. In this paper, a novel measurement method is developed to measure the displacement and velocity of the web precisely and directly. The proposed algorithm is based on the traditional single field encoder principle, and the scale grating has been replaced with a printed grating on the web. Because a printed grating cannot be as accuratemore » as a scale grating in a traditional encoder, there will inevitably be variations in pitch and line-width, and the motion of the web should be measured even though there are variations in pitch and line-width in the printed grating patterns. For this reason, the developed algorithm includes a precise method of estimating the variations in pitch. In addtion, a method of correcting the Lissajous curve is presented for precision phase interpolation to improve measurement accuracy by correcting Lissajous circle to unit circle. The performance of the developed method is evaluated by simulation and experiment. In the experiment, the displacement error was less than 2.5 μm and the velocity error of 1σ was about 0.25%, while the grating scale moved 30 mm.« less

Direct and precise measurement of displacement and velocity of flexible web in roll-to-roll manufacturing systems

NASA Astrophysics Data System (ADS)

Kang, Dongwoo; duk Kim, Young; Lee, Eonseok; Choi, Young-Man; Lee, Taik-Min; Kim, Dongmin

2013-12-01

Interest in the production of printed electronics using a roll-to-roll system has gradually increased due to its low mass-production costs and compatibility with flexible substrate. To improve the accuracy of roll-to-roll manufacturing systems, the movement of the web needs to be measured precisely in advance. In this paper, a novel measurement method is developed to measure the displacement and velocity of the web precisely and directly. The proposed algorithm is based on the traditional single field encoder principle, and the scale grating has been replaced with a printed grating on the web. Because a printed grating cannot be as accurate as a scale grating in a traditional encoder, there will inevitably be variations in pitch and line-width, and the motion of the web should be measured even though there are variations in pitch and line-width in the printed grating patterns. For this reason, the developed algorithm includes a precise method of estimating the variations in pitch. In addtion, a method of correcting the Lissajous curve is presented for precision phase interpolation to improve measurement accuracy by correcting Lissajous circle to unit circle. The performance of the developed method is evaluated by simulation and experiment. In the experiment, the displacement error was less than 2.5 μm and the velocity error of 1σ was about 0.25%, while the grating scale moved 30 mm.

Strand displacement amplification as an in vitro model for rolling-circle replication: deletion formation and evolution during serial transfer.

PubMed Central

Walter, N G; Strunk, G

1994-01-01

Strand displacement amplification is an isothermal DNA amplification reaction based on a restriction endonuclease nicking its recognition site and a polymerase extending the nick at its 3' end, displacing the downstream strand. The reaction resembles rolling-circle replication of single-stranded phages and small plasmids. The displaced sense strand serves as target for an antisense reaction and vice versa, resulting in exponential growth and the autocatalytic nature of this in vitro reaction as long as the template is the limiting agent. We describe the optimization of strand displacement amplification for in vitro evolution experiments under serial transfer conditions. The reaction was followed and controlled by use of the fluorescent dye thiazole orange binding to the amplified DNA. We were able to maintain exponential growth conditions with a doubling time of 3.0 min throughout 100 transfers or approximately 350 molecular generations by using an automatic handling device. Homology of in vitro amplification with rolling-circle replication was mirrored by the occurring evolutionary processes. Deletion events most likely caused by a slipped mispairing mechanism as postulated for in vivo replication took place. Under our conditions, the mutation rate was high and a molecular quasi-species formed with a mutant lacking internal hairpin formation ability and thus outgrowing all other species under dGTP/dCTP deficiency. Images PMID:8058737

A cascade signal amplification strategy for sensitive and label-free DNA detection based on Exo III-catalyzed recycling coupled with rolling circle amplification.

PubMed

Liu, Xingti; Xue, Qingwang; Ding, Yongshun; Zhu, Jing; Wang, Lei; Jiang, Wei

2014-06-07

A sensitive and label-free fluorescence assay for DNA detection has been developed based on cascade signal amplification combining exonuclease III (Exo III)-catalyzed recycling with rolling circle amplification. In this assay, probe DNA hybridized with template DNA was coupled onto magnetic nanoparticles to prepare a magnetic bead-probe (MNB-probe)-template complex. The complex could hybridize with the target DNA, which transformed the protruding 3' terminus of template DNA into a blunt end. Exo III could then digest template DNA, liberating the MNB-probe and target DNA. The intact target DNA then hybridized with other templates and released more MNB-probes. The liberated MNB-probe captured the primer, circular DNA and then initiated the rolling circle amplification (RCA) reaction, realizing a cascade signal amplification. Using this cascade amplification strategy, a sensitive DNA detection method was developed which was superior to many existing Exo III-based signal amplification methods. Moreover, N-methyl mesoporphyrin IX, which had a pronounced structural selectivity for the G-quadruplex, was used to combine with the G-quadruplex RCA products and generate a fluorescence signal, avoiding the need for any fluorophore-label probes. The spike and recovery experiments in a human serum sample indicated that our assay also had great potential for DNA detection in real biological samples.

Application of round grating angle measurement composite error amendment in the online measurement accuracy improvement of large diameter

NASA Astrophysics Data System (ADS)

Wang, Biao; Yu, Xiaofen; Li, Qinzhao; Zheng, Yu

2008-10-01

The paper aiming at the influence factor of round grating dividing error, rolling-wheel produce eccentricity and surface shape errors provides an amendment method based on rolling-wheel to get the composite error model which includes all influence factors above, and then corrects the non-circle measurement angle error of the rolling-wheel. We make soft simulation verification and have experiment; the result indicates that the composite error amendment method can improve the diameter measurement accuracy with rolling-wheel theory. It has wide application prospect for the measurement accuracy higher than 5 μm/m.

Rapid screening for human-pathogenic Mucorales using rolling circle amplification.

PubMed

Dolatabadi, S; Najafzadeh, M J; de Hoog, G S

2014-12-01

Mucormycosis has emerged as a relatively common severe mycosis in patients with haematological and allogeneic stem cell transplantation. Source of transmission is from unidentified sources in the environment. Early diagnosis of infection and its source of contamination are paramount for rapid and appropriate therapy. In this study, rolling circle amplification (RCA) is introduced as a sensitive, specific and reproducible isothermal DNA amplification technique for rapid molecular identification of six of the most virulent species (Rhizopus microsporus, R. arrhizus var. arrhizus, R. arrhizus var. delemar, Mucor irregularis, Mucor circinelloides, Lichtheimia ramosa, Lichtheimia corymbifera). DNAs of target species were successfully amplified, with no cross reactivity between species. RCA can be considered as a rapid detection method with high specificity and sensitivity, suitable for large screening. © 2014 Blackwell Verlag GmbH.

Characterization of a Novel Close-to-Root Papillomavirus from a Florida Manatee by Using Multiply Primed Rolling-Circle Amplification: Trichechus manatus latirostris Papillomavirus Type 1†

PubMed Central

Rector, Annabel; Bossart, Gregory D.; Ghim, Shin-Je; Sundberg, John P.; Jenson, A. Bennett; Van Ranst, Marc

2004-01-01

By using an isothermal multiply primed rolling-circle amplification protocol, the complete genomic DNA of a novel papillomavirus was amplified from a skin lesion biopsy of a Florida manatee (Trichechus manatus latirostris), one of the most endangered marine mammals in United States coastal waters. The nucleotide sequence, genome organization, and phylogenetic position of the Trichechus manatus latirostris papillomavirus type 1 (TmPV-1) were determined. TmPV-1 is the first virus isolated from the order of Sirenia. A phylogenetic analysis shows that TmPV-1 is only distantly related to other papillomavirus sequences, and it appears in our phylogenetic tree as a novel close-to-root papillomavirus genus. PMID:15507660

Rolling Circle Amplification For Spatially Directed Synthesis Of A Solid Phase Anchored Single-Stranded DNA Molecule

NASA Astrophysics Data System (ADS)

Reiß, Edda; Hölzel, Ralph; von Nickisch-Rosenegk, Markus; Bier, Frank F.

2006-09-01

In this article the usefulness of the enzyme phi29 DNA polymerase and the principle of rolling circle amplification (RCA) for creating single-stranded DNA (ssDNA) nanostructures is described. Currently we are working on the spatial orientation of a growing ssDNA molecule during its RCA-based synthesis by the application of a hydrodynamic force. Starting at an immobilized primer at single molecule level, the aim is to construct a nanostructure of known location and orientation, providing multiple repeating binding sites that can be addressed via complementary base-pairing. Proof-of-principle experiments demonstrate the potential of the enzymatic reaction. ssDNA molecules of more than 20 μm length were created at an immobilized primer and detected by means of fluorescence microscopy.

Theoretical damping in roll and rolling moment due to differential wing incidence for slender cruciform wings and wing-body combinations

NASA Technical Reports Server (NTRS)

Adams, Gaynor J; DUGAN DUANE W

1952-01-01

A method of analysis based on slender-wing theory is developed to investigate the characteristics in roll of slender cruciform wings and wing-body combinations. The method makes use of the conformal mapping processes of classical hydrodynamics which transform the region outside a circle and the region outside an arbitrary arrangement of line segments intersecting at the origin. The method of analysis may be utilized to solve other slender cruciform wing-body problems involving arbitrarily assigned boundary conditions. (author)

Signal amplification by rolling circle amplification on DNA microarrays

PubMed Central

Nallur, Girish; Luo, Chenghua; Fang, Linhua; Cooley, Stephanie; Dave, Varshal; Lambert, Jeremy; Kukanskis, Kari; Kingsmore, Stephen; Lasken, Roger; Schweitzer, Barry

2001-01-01

While microarrays hold considerable promise in large-scale biology on account of their massively parallel analytical nature, there is a need for compatible signal amplification procedures to increase sensitivity without loss of multiplexing. Rolling circle amplification (RCA) is a molecular amplification method with the unique property of product localization. This report describes the application of RCA signal amplification for multiplexed, direct detection and quantitation of nucleic acid targets on planar glass and gel-coated microarrays. As few as 150 molecules bound to the surface of microarrays can be detected using RCA. Because of the linear kinetics of RCA, nucleic acid target molecules may be measured with a dynamic range of four orders of magnitude. Consequently, RCA is a promising technology for the direct measurement of nucleic acids on microarrays without the need for a potentially biasing preamplification step. PMID:11726701

DNA Hydrogel with Tunable pH-Responsive Properties Produced by Rolling Circle Amplification.

PubMed

Xu, Wanlin; Huang, Yishun; Zhao, Haoran; Li, Pan; Liu, Guoyuan; Li, Jing; Zhu, Chengshen; Tian, Leilei

2017-12-22

Recently, smart DNA hydrogels, which are generally formed by the self-assembly of oligonucleotides or through the cross-linking of oligonucleotide-polymer hybrids, have attracted tremendous attention. However, the difficulties of fabricating DNA hydrogels limit their practical applications. We report herein a novel method for producing pH-responsive hydrogels by rolling circle amplification (RCA). In this method, pH-sensitive cross-linking sites were introduced into the polymeric DNA chains during DNA synthesis. As the DNA sequence can be precisely defined by its template, the properties of such hydrogels can be finely tuned in a very facile way through template design. We have investigated the process of hydrogel formation and pH-responsiveness to provide rationales for functional hydrogel design based on the RCA reaction. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Voltammetric determination of attomolar levels of a sequence derived from the genom of hepatitis B virus by using molecular beacon mediated circular strand displacement and rolling circle amplification.

PubMed

Huang, Shan; Feng, Mengmeng; Li, Jiawen; Liu, Yi; Xiao, Qi

2018-03-03

The authors describe an electrochemical method for the determination of the single-stranded DNA (ssDNA) oligonucleotide with a sequence derived from the genom of hepatitis B virus (HBV). It is making use of circular strand displacement (CSD) and rolling circle amplification (RCA) strategies mediated by a molecular beacon (MB). This ssDNA hybridizes with the loop portion of the MB immobilized on the surface of a gold electrode, while primer DNA also hybridizes with the rest of partial DNA sequences of MB. This triggers the MB-mediated CSD. The RCA is then initiated to produce a long DNA strand with multiple tandem-repeat sequences, and this results in a significant increase of the differential pulse voltammetric response of the electrochemical probe Methylene Blue at a rather low working potential of -0.24 V (vs. Ag/AgCl). Under optimal experimental conditions, the assay displays an ultrahigh sensitivity (with a 2.6 aM detection limit) and excellent selectivity. Response is linear in the 10 to 700 aM DNA concentration range. Graphical abstract Schematic of a voltammetric method for the determination of attomolar levels of target DNA. It is based on molecular beacon mediated circular strand displacement and rolling circle amplification strategies. Under optimal experimental conditions, the assay displays an ultrahigh sensitivity with a 2.6 aM detection limit and excellent selectivity.

A Rolling Circle Replication Mechanism Produces Multimeric Lariats of Mitochondrial DNA in Caenorhabditis elegans

PubMed Central

Lewis, Samantha C.; Joers, Priit; Willcox, Smaranda; Griffith, Jack D.; Jacobs, Howard T.; Hyman, Bradley C.

2015-01-01

Mitochondrial DNA (mtDNA) encodes respiratory complex subunits essential to almost all eukaryotes; hence respiratory competence requires faithful duplication of this molecule. However, the mechanism(s) of its synthesis remain hotly debated. Here we have developed Caenorhabditis elegans as a convenient animal model for the study of metazoan mtDNA synthesis. We demonstrate that C. elegans mtDNA replicates exclusively by a phage-like mechanism, in which multimeric molecules are synthesized from a circular template. In contrast to previous mammalian studies, we found that mtDNA synthesis in the C. elegans gonad produces branched-circular lariat structures with multimeric DNA tails; we were able to detect multimers up to four mtDNA genome unit lengths. Further, we did not detect elongation from a displacement-loop or analogue of 7S DNA, suggesting a clear difference from human mtDNA in regard to the site(s) of replication initiation. We also identified cruciform mtDNA species that are sensitive to cleavage by the resolvase RusA; we suggest these four-way junctions may have a role in concatemer-to-monomer resolution. Overall these results indicate that mtDNA synthesis in C. elegans does not conform to any previously documented metazoan mtDNA replication mechanism, but instead are strongly suggestive of rolling circle replication, as employed by bacteriophages. As several components of the metazoan mitochondrial DNA replisome are likely phage-derived, these findings raise the possibility that the rolling circle mtDNA replication mechanism may be ancestral among metazoans. PMID:25693201

L-RCA (ligation-rolling circle amplification): a general method for genotyping of single nucleotide polymorphisms (SNPs)

PubMed Central

Qi, Xiaoquan; Bakht, Saleha; Devos, Katrien M.; Gale, Mike D.; Osbourn, Anne

2001-01-01

A flexible, non-gel-based single nucleotide polymorphism (SNP) detection method is described. The method adopts thermostable ligation for allele discrimination and rolling circle amplification (RCA) for signal enhancement. Clear allelic discrimination was achieved after staining of the final reaction mixtures with Cybr-Gold and visualisation by UV illumination. The use of a compatible buffer system for all enzymes allows the reaction to be initiated and detected in the same tube or microplate well, so that the experiment can be scaled up easily for high-throughput detection. Only a small amount of DNA (i.e. 50 ng) is required per assay, and use of carefully designed short padlock probes coupled with generic primers and probes make the SNP detection cost effective. Biallelic assay by hybridisation of the RCA products with fluorescence dye-labelled probes is demonstrated, indicating that ligation-RCA (L-RCA) has potential for multiplexed assays. PMID:11713336

Ultrasensitive Detection of Low-Abundance Surface-Marker Protein using Isothermal Rolling Circle Amplification in Microfluidic Nano-Liter Platform

PubMed Central

Konry, Tania; Yarmush, Joel M.; Irimia, Daniel

2011-01-01

With advances in immunology and cancer biology, there is an unmet need for increasingly sensitive systems to monitor the expression of specific cell markers for the development of new diagnostic and therapeutic tools. To address this challenge, we have applied a highly sensitive labeling method that translates antigen-antibody recognition processes into DNA detection event that can be greatly amplified via isothermal Rolling Circle Amplification (RCA). By merging the single-molecule detection power of RCA reaction with microfluidic technology we were able to demonstrate that identification of specific protein markers can be achieved on tumor cell surface in miniaturized nano-liter reaction droplets. Furthermore, this combined approach of signal amplification in a microfluidic format could extend the utility of existing methods by reducing sample and reagent consumption and enhancing the sensitivities and specificities for various applications, including early diagnosis of cancer. PMID:21294269

Break-induced replication and recombinational telomere elongation in yeast.

PubMed

McEachern, Michael J; Haber, James E

2006-01-01

When a telomere becomes unprotected or if only one end of a chromosomal double-strand break succeeds in recombining with a template sequence, DNA can be repaired by a recombination-dependent DNA replication process termed break-induced replication (BIR). In budding yeasts, there are two BIR pathways, one dependent on the Rad51 recombinase protein and one Rad51 independent; these two repair processes lead to different types of survivors in cells lacking the telomerase enzyme that is required for normal telomere maintenance. Recombination at telomeres is triggered by either excessive telomere shortening or disruptions in the function of telomere-binding proteins. Telomere elongation by BIR appears to often occur through a "roll and spread" mechanism. In this process, a telomeric circle produced by recombination at a dysfunctional telomere acts as a template for a rolling circle BIR event to form an elongated telomere. Additional BIR events can then copy the elongated sequence to all other telomeres.

Controlled Microwave Heating Accelerates Rolling Circle Amplification.

PubMed

Yoshimura, Takeo; Suzuki, Takamasa; Mineki, Shigeru; Ohuchi, Shokichi

2015-01-01

Rolling circle amplification (RCA) generates single-stranded DNAs or RNA, and the diverse applications of this isothermal technique range from the sensitive detection of nucleic acids to analysis of single nucleotide polymorphisms. Microwave chemistry is widely applied to increase reaction rate as well as product yield and purity. The objectives of the present research were to apply microwave heating to RCA and indicate factors that contribute to the microwave selective heating effect. The microwave reaction temperature was strictly controlled using a microwave applicator optimized for enzymatic-scale reactions. Here, we showed that microwave-assisted RCA reactions catalyzed by either of the four thermostable DNA polymerases were accelerated over 4-folds compared with conventional RCA. Furthermore, the temperatures of the individual buffer components were specifically influenced by microwave heating. We concluded that microwave heating accelerated isothermal RCA of DNA because of the differential heating mechanisms of microwaves on the temperatures of reaction components, although the overall reaction temperatures were the same.

A Sequence-Independent Strategy for Detection and Cloning of Circular DNA Virus Genomes by Using Multiply Primed Rolling-Circle Amplification

PubMed Central

Rector, Annabel; Tachezy, Ruth; Van Ranst, Marc

2004-01-01

The discovery of novel viruses has often been accomplished by using hybridization-based methods that necessitate the availability of a previously characterized virus genome probe or knowledge of the viral nucleotide sequence to construct consensus or degenerate PCR primers. In their natural replication cycle, certain viruses employ a rolling-circle mechanism to propagate their circular genomes, and multiply primed rolling-circle amplification (RCA) with φ29 DNA polymerase has recently been applied in the amplification of circular plasmid vectors used in cloning. We employed an isothermal RCA protocol that uses random hexamer primers to amplify the complete genomes of papillomaviruses without the need for prior knowledge of their DNA sequences. We optimized this RCA technique with extracted human papillomavirus type 16 (HPV-16) DNA from W12 cells, using a real-time quantitative PCR assay to determine amplification efficiency, and obtained a 2.4 × 104-fold increase in HPV-16 DNA concentration. We were able to clone the complete HPV-16 genome from this multiply primed RCA product. The optimized protocol was subsequently applied to a bovine fibropapillomatous wart tissue sample. Whereas no papillomavirus DNA could be detected by restriction enzyme digestion of the original sample, multiply primed RCA enabled us to obtain a sufficient amount of papillomavirus DNA for restriction enzyme analysis, cloning, and subsequent sequencing of a novel variant of bovine papillomavirus type 1. The multiply primed RCA method allows the discovery of previously unknown papillomaviruses, and possibly also other circular DNA viruses, without a priori sequence information. PMID:15113879

Analytically Sensitive Protein Detection in Microtiter Plates by Proximity Ligation with Rolling Circle Amplification.

PubMed

Ebai, Tonge; Souza de Oliveira, Felipe Marques; Löf, Liza; Wik, Lotta; Schweiger, Caroline; Larsson, Anders; Keilholtz, Ulrich; Haybaeck, Johannes; Landegren, Ulf; Kamali-Moghaddam, Masood

2017-09-01

Detecting proteins at low concentrations in plasma is crucial for early diagnosis. Current techniques in clinical routine, such as sandwich ELISA, provide sensitive protein detection because of a dependence on target recognition by pairs of antibodies, but detection of still lower protein concentrations is often called for. Proximity ligation assay with rolling circle amplification (PLARCA) is a modified proximity ligation assay (PLA) for analytically specific and sensitive protein detection via binding of target proteins by 3 antibodies, and signal amplification via rolling circle amplification (RCA) in microtiter wells, easily adapted to instrumentation in use in hospitals. Proteins captured by immobilized antibodies were detected using a pair of oligonucleotide-conjugated antibodies. Upon target recognition these PLA probes guided oligonucleotide ligation, followed by amplification via RCA of circular DNA strands that formed in the reaction. The RCA products were detected by horseradish peroxidase-labeled oligonucleotides to generate colorimetric reaction products with readout in an absorbance microplate reader. We compared detection of interleukin (IL)-4, IL-6, IL-8, p53, and growth differentiation factor 15 (GDF-15) by PLARCA and conventional sandwich ELISA or immuno-RCA. PLARCA detected lower concentrations of proteins and exhibited a broader dynamic range compared to ELISA and iRCA using the same antibodies. IL-4 and IL-6 were detected in clinical samples at femtomolar concentrations, considerably lower than for ELISA. PLARCA offers detection of lower protein levels and increased dynamic ranges compared to ELISA. The PLARCA procedure may be adapted to routine instrumentation available in hospitals and research laboratories. © 2017 American Association for Clinical Chemistry.

Active Site Sharing and Subterminal Hairpin Recognition in a New Class of DNA Transposases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ronning, Donald R.; Guynet, Catherine; Ton-Hoang, Bao

2010-07-20

Many bacteria harbor simple transposable elements termed insertion sequences (IS). In Helicobacter pylori, the chimeric IS605 family elements are particularly interesting due to their proximity to genes encoding gastric epithelial invasion factors. Protein sequences of IS605 transposases do not bear the hallmarks of other well-characterized transposases. We have solved the crystal structure of full-length transposase (TnpA) of a representative member, ISHp608. Structurally, TnpA does not resemble any characterized transposase; rather, it is related to rolling circle replication (RCR) proteins. Consistent with RCR, Mg{sup 2+} and a conserved tyrosine, Tyr127, are essential for DNA nicking and the formation of a covalentmore » intermediate between TnpA and DNA. TnpA is dimeric, contains two shared active sites, and binds two DNA stem loops representing the conserved inverted repeats near each end of ISHp608. The cocrystal structure with stem-loop DNA illustrates how this family of transposases specifically recognizes and pairs ends, necessary steps during transposition.« less

To believe the past or to trust the future

NASA Astrophysics Data System (ADS)

Jin, Fengtao; Zhou, Zhaoyan

2012-01-01

A small ball rolls down from a quarter-circle to a frictionless plane. What will be the magnitude of the normal force when the ball arrives at the tangent point of the circle and the plane? According to the centripetal force formula, the normal force will be 3mg when the curvature radius of the circle is considered, but will be mg instead when the curvature radius of the plane is considered. Which one is the correct answer? The difficulty is that Newton's second law requires the second time derivative of displacement to be continuous; however, this condition is not fulfilled at the tangent point. In this paper we will discuss several possible solutions to this problem in detail.

Effects of rolling conditions on recrystallization microstructure and texture in magnetostrictive Fe-Ga-Al rolled sheets

NASA Astrophysics Data System (ADS)

Li, Jiheng; Liu, Yangyang; Li, Xiaojuan; Mu, Xing; Bao, Xiaoqian; Gao, Xuexu

2018-07-01

The effects of different rolling conditions on the microstructure and texture of primary and secondary recrystallization in magnetostrictive Fe82Ga9Al9+0.1at%NbC alloy sheets were investigated. After the primary recrystallization annealing at 850 °C for 5 min, the as-rolled sheets prepared by warm-cold rolling with an intermediate annealing, can be fully recrystallized, and obtain the homogeneous matrix in which the fine dispersed NbC precipitate particles are distributed. The primary recrystallization textures of sheets with different rolling conditions consist mostly of strong {1 0 0} textures, γ-fiber textures, {4 1 1}〈1 4 8〉 texture and weak Goss texture. In the primary recrystallized sheets prepared by warm-cold rolling with an intermediate annealing, the high energy grain boundaries and ∑9 boundaries have the highest proportion. After high temperature annealing, the secondary recrystallizations of Goss grains in these sheets are more complete, and the size of abnormal grown Goss grain is up to several centimeters, which results in the strongest Goss texture. Correspondingly, the largest magnetostriction of 183 ppm is observed. The sample prepared by warm-cold rolling with an intermediate annealing, has homogeneous primary matrix, special texture components and grain boundary distribution, all of which provide a better surrounding for the abnormal growth of Goss grains. This work indicates that the control of rolling conditions of Fe-Ga-Al alloy sheets is necessary to achieve the strong Goss texture and obtain a possible high magnetostriction if other appropriate conditions (stress, domain structure) are achieved.

Porcine circovirus: transcription and rolling-circle DNA replication

USDA-ARS?s Scientific Manuscript database

This review summarizes the molecular studies pertaining to porcine circovirus (PCV) transcription and DNA replication. The genome of PCV is circular, single-stranded DNA and contains 1759-1768 nucleotides. Both the genome-strand (packaged in the virus particle) and the complementary-strand (synthesi...

Strengthening Resilience in Families

ERIC Educational Resources Information Center

Guild, Diane; Espiner, Deborah

2014-01-01

Rolling with Resilience (RwR) provides a springboard for developing strategies that build strengths and supports to foster developmental assets in children and youth (Benson, Scales, & Roehlkepartain, 2011). In Circle of Courage terms, resilience is strengthened by opportunities for Belonging, Mastery, Independence, and Generosity (Brendtro,…

Immobilized rolling circle amplification on extended-gate field-effect transistors with integrated readout circuits for early detection of platelet-derived growth factor.

PubMed

Lin, Ming-Yu; Hsu, Wen-Yang; Yang, Yuh-Shyong; Huang, Jo-Wen; Chung, Yueh-Lin; Chen, Hsin

2016-07-01

Detection of tumor-related proteins with high specificity and sensitivity is important for early diagnosis and prognosis of cancers. While protein sensors based on antibodies are not easy to keep for a long time, aptamers (single-stranded DNA) are found to be a good alternative for recognizing tumor-related protein specifically. This study investigates the feasibility of employing aptamers to recognize the platelet-derived growth factor (PDGF) specifically and subsequently triggering rolling circle amplification (RCA) of DNAs on extended-gate field-effect transistors (EGFETs) to enhance the sensitivity. The EGFETs are fabricated by the standard CMOS technology and integrated with readout circuits monolithically. The monolithic integration not only avoids the wiring complexity for a large sensor array but also enhances the sensor reliability and facilitates massive production for commercialization. With the RCA primers immobilized on the sensory surface, the protein signal is amplified as the elongation of DNA, allowing the EGFET to achieve a sensitivity of 8.8 pM, more than three orders better than that achieved by conventional EGFETs. Moreover, the responses of EGFETs are able to indicate quantitatively the reaction rates of RCA, facilitating the estimation on the protein concentration. Our experimental results demonstrate that immobilized RCA on EGFETs is a useful, label-free method for early diagnosis of diseases related to low-concentrated tumor makers (e.g., PDGF) for serum sample, as well as for monitoring the synthesis of various DNA nanostructures in real time. Graphical Abstract The tumor-related protein, PDGF, is detected by immobilizing rolling circle amplification on an EGFET with integrated readout circuit.

Classroom Discourse Frames.

ERIC Educational Resources Information Center

Pennington, Martha C.

An analysis of classroom discourse proposes four frames, modeled as concentric circles. The inner most circle is the lesson frame, removed or sheltered from outside influences and most likely, in a language class, to maintain second-language usage. The next frame from the center is the lesson-support frame, an intermediate layer of classroom…

Design of a platform technology for systemic delivery of siRNA to tumours using rolling circle transcription

NASA Astrophysics Data System (ADS)

Jang, Mihue; Kim, Jong Hwan; Nam, Hae Yun; Kwon, Ick Chan; Ahn, Hyung Jun

2015-08-01

For therapeutic applications of siRNA, there are technical challenges with respect to targeted and systemic delivery. We here report a new siRNA carrier, RNAtr NPs, in a way that multiple tandem copies of RNA hairpins as a result of rolling circle transcription (RCT) can be readily adapted in tumour-targeted and systemic siRNA delivery. RNAtr NPs provide a means of condensing large amounts of multimeric RNA transcripts into the compact nanoparticles, especially without the aid of polycationic agents, and thus reduce the risk of immunogenicity and cytotoxicity by avoiding the use of synthetic polycationic reagents. This strategy allows the design of a platform technology for systemic delivery of siRNA to tumour sites, because RCT reaction, which enzymatically generates RNA polymers in multiple copy numbers at low cost, can lead to directly accessible routes to targeted and systemic delivery. Therefore, RNAtr NPs suggest great potentials as the siRNA therapeutics for cancer treatment.

Rolling Circle Translation of Circular RNA in Living Human Cells.

PubMed

Abe, Naoko; Matsumoto, Ken; Nishihara, Mizuki; Nakano, Yukiko; Shibata, Aya; Maruyama, Hideto; Shuto, Satoshi; Matsuda, Akira; Yoshida, Minoru; Ito, Yoshihiro; Abe, Hiroshi

2015-11-10

We recently reported that circular RNA is efficiently translated by a rolling circle amplification (RCA) mechanism in a cell-free Escherichia coli translation system. Recent studies have shown that circular RNAs composed of exonic sequences are abundant in human cells. However, whether these circular RNAs can be translated into proteins within cells remains unclear. In this study, we prepared circular RNAs with an infinite open reading frame and tested their translation in eukaryotic systems. Circular RNAs were translated into long proteins in rabbit reticulocyte lysate in the absence of any particular element for internal ribosome entry, a poly-A tail, or a cap structure. The translation systems in eukaryote can accept much simpler RNA as a template for protein synthesis by cyclisation. Here, we demonstrated that the circular RNA is efficiently translated in living human cells to produce abundant protein product by RCA mechanism. These findings suggest that translation of exonic circular RNAs present in human cells is more probable than previously thought.

Rolling Circle Translation of Circular RNA in Living Human Cells

PubMed Central

Abe, Naoko; Matsumoto, Ken; Nishihara, Mizuki; Nakano, Yukiko; Shibata, Aya; Maruyama, Hideto; Shuto, Satoshi; Matsuda, Akira; Yoshida, Minoru; Ito, Yoshihiro; Abe, Hiroshi

2015-01-01

We recently reported that circular RNA is efficiently translated by a rolling circle amplification (RCA) mechanism in a cell-free Escherichia coli translation system. Recent studies have shown that circular RNAs composed of exonic sequences are abundant in human cells. However, whether these circular RNAs can be translated into proteins within cells remains unclear. In this study, we prepared circular RNAs with an infinite open reading frame and tested their translation in eukaryotic systems. Circular RNAs were translated into long proteins in rabbit reticulocyte lysate in the absence of any particular element for internal ribosome entry, a poly-A tail, or a cap structure. The translation systems in eukaryote can accept much simpler RNA as a template for protein synthesis by cyclisation. Here, we demonstrated that the circular RNA is efficiently translated in living human cells to produce abundant protein product by RCA mechanism. These findings suggest that translation of exonic circular RNAs present in human cells is more probable than previously thought. PMID:26553571

Repressor logic modules assembled by rolling circle amplification platform to construct a set of logic gates

PubMed Central

Wei, Hua; Hu, Bo; Tang, Suming; Zhao, Guojie; Guan, Yifu

2016-01-01

Small molecule metabolites and their allosterically regulated repressors play an important role in many gene expression and metabolic disorder processes. These natural sensors, though valuable as good logic switches, have rarely been employed without transcription machinery in cells. Here, two pairs of repressors, which function in opposite ways, were cloned, purified and used to control DNA replication in rolling circle amplification (RCA) in vitro. By using metabolites and repressors as inputs, RCA signals as outputs, four basic logic modules were constructed successfully. To achieve various logic computations based on these basic modules, we designed series and parallel strategies of circular templates, which can further assemble these repressor modules in an RCA platform to realize twelve two-input Boolean logic gates and a three-input logic gate. The RCA-output and RCA-assembled platform was proved to be easy and flexible for complex logic processes and might have application potential in molecular computing and synthetic biology. PMID:27869177

A novel electrochemical biosensor for ultrasensitive and specific detection of DNA based on molecular beacon mediated circular strand displacement and rolling circle amplification.

PubMed

Cheng, Wei; Zhang, Wei; Yan, Yurong; Shen, Bo; Zhu, Dan; Lei, Pinhua; Ding, Shijia

2014-12-15

A novel electrochemical biosensing strategy was developed for ultrasensitive and specific detection of target DNA using a cascade signal amplification based on molecular beacon (MB) mediated circular strand displacement (CSD), rolling circle amplification (RCA), biotin-strepavidin system, and enzymatic amplification. The target DNA hybridized with the loop portion of MB probe immobilized on the gold electrode and triggered the CSD, leading to multiple biotin-tagged DNA duplex. Furthermore, via biotin-streptavidin interaction, the RCA was implemented, producing long massive tandem-repeat DNA sequences for binding numerous biotinylated detection probes. This enabled an ultrasensitive electrochemical readout by further employing the streptavidin-alkaline phosphatase. The proposed biosensor showed very high sensitivity and selectivity with a dynamic response range from 1 fM to 100 pM. The proposed strategy could have the potential for applying in clinical molecular diagnostics and environmental monitoring. Copyright © 2014 Elsevier B.V. All rights reserved.

Designing a Micromixer for Rolling Circle Amplification in Cancer Biomarker Detection

NASA Astrophysics Data System (ADS)

Altural, Hayriye

2015-03-01

Rolling circle amplification (RCA) is an alternative method to the Polymerase Chain Reaction based amplification for point-of-care (POC) diagnosis. In future personalized cancer diagnostic for POC applications, smaller, faster and cheaper methods are needed instead of costly and time-consuming laboratory tests. Microfluidic chips can perform the detection of cancer biomarkers within less analysis time, and provide for improvement in the sensitivity and specificity required for biochemical analysis as well. Rapid mixing is essential in the chips used in cancer diagnostic. The goal of this study is to design a micromixer for rapid RCA-based analysis and develop the assay time in cancer biomarker detection. By combining assays with micromixers, multi-step bioreactions in microfluidic chips may be achieved with minimal external control. Here, simulation results related to the micromixer are obtained by COMSOL software. The Scientific and Technological Research Council of Turkey (TUBITAK) is acknowledged for granting of H. Altural postdoctoral study in the framework of TUBITAK-BIDEB 2219-International Postdoctoral Research Scholarship Program.

Specific RNA self-cleavage in coconut cadang cadang viroid: potential for a role in rolling circle replication.

PubMed Central

Liu, Y H; Symons, R H

1998-01-01

The rolling circle replication of the small, single-stranded viroid RNAs requires a specific processing reaction to produce monomeric RNAs that are ligated into the final circular form. For avocado sunblotch viroid, peach latent mosaic viroid, and chrysanthemum chlorotic mottle viroid, the hammerhead self-cleavage reaction is considered to provide this processing reaction. We have searched for a similar type of reaction in the 246-nt coconut cadang cadang viroid, the smallest viroid of the 24-member potato spindle tuber viroid (PSTV) group. RNA transcripts prepared from the cloned central or C domain of this viroid self-cleaved specifically after denaturation with methylmercuric hydroxide followed by incubation in the presence of spermidine but in the absence of added magnesium ions. The unique cleavage site was located in the bottom strand of the C domain within a potential hairpin structure that is conserved within members of all three subgroups of the PSTV group of viroids. PMID:9630248

Controlled Microwave Heating Accelerates Rolling Circle Amplification

PubMed Central

Yoshimura, Takeo; Suzuki, Takamasa; Mineki, Shigeru; Ohuchi, Shokichi

2015-01-01

Rolling circle amplification (RCA) generates single-stranded DNAs or RNA, and the diverse applications of this isothermal technique range from the sensitive detection of nucleic acids to analysis of single nucleotide polymorphisms. Microwave chemistry is widely applied to increase reaction rate as well as product yield and purity. The objectives of the present research were to apply microwave heating to RCA and indicate factors that contribute to the microwave selective heating effect. The microwave reaction temperature was strictly controlled using a microwave applicator optimized for enzymatic-scale reactions. Here, we showed that microwave-assisted RCA reactions catalyzed by either of the four thermostable DNA polymerases were accelerated over 4-folds compared with conventional RCA. Furthermore, the temperatures of the individual buffer components were specifically influenced by microwave heating. We concluded that microwave heating accelerated isothermal RCA of DNA because of the differential heating mechanisms of microwaves on the temperatures of reaction components, although the overall reaction temperatures were the same. PMID:26348227

Fairy circle landscapes under the sea

PubMed Central

Ruiz-Reynés, Daniel; Gomila, Damià; Sintes, Tomàs; Hernández-García, Emilio; Marbà, Núria; Duarte, Carlos M.

2017-01-01

Short-scale interactions yield large-scale vegetation patterns that, in turn, shape ecosystem function across landscapes. Fairy circles, which are circular patches bare of vegetation within otherwise continuous landscapes, are characteristic features of semiarid grasslands. We report the occurrence of submarine fairy circle seascapes in seagrass meadows and propose a simple model that reproduces the diversity of seascapes observed in these ecosystems as emerging from plant interactions within the meadow. These seascapes include two extreme cases, a continuous meadow and a bare landscape, along with intermediate states that range from the occurrence of persistent but isolated fairy circles, or solitons, to seascapes with multiple fairy circles, banded vegetation, and “leopard skin” patterns consisting of bare seascapes dotted with plant patches. The model predicts that these intermediate seascapes extending across kilometers emerge as a consequence of local demographic imbalances along with facilitative and competitive interactions among the plants with a characteristic spatial scale of 20 to 30 m, consistent with known drivers of seagrass performance. The model, which can be extended to clonal growth plants in other landscapes showing fairy rings, reveals that the different seascapes observed hold diagnostic power as to the proximity of seagrass meadows to extinction points that can be used to identify ecosystems at risks. PMID:28782035

77 FR 56760 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-14

... Airworthiness Directives; Rolls-Royce plc Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT... all Rolls-Royce plc (RR) RB211-Trent 800 series turbofan engines. This AD requires removing from...-17, 892-17, 892B-17, and 895-17 turbofan engines that have an intermediate pressure (IP) turbine disc...

Replication intermediates of the linear mitochondrial DNA of Candida parapsilosis suggest a common recombination based mechanism for yeast mitochondria.

PubMed

Gerhold, Joachim M; Sedman, Tiina; Visacka, Katarina; Slezakova, Judita; Tomaska, Lubomir; Nosek, Jozef; Sedman, Juhan

2014-08-15

Variation in the topology of mitochondrial DNA (mtDNA) in eukaryotes evokes the question if differently structured DNAs are replicated by a common mechanism. RNA-primed DNA synthesis has been established as a mechanism for replicating the circular animal/mammalian mtDNA. In yeasts, circular mtDNA molecules were assumed to be templates for rolling circle DNA-replication. We recently showed that in Candida albicans, which has circular mapping mtDNA, recombination driven replication is a major mechanism for replicating a complex branched mtDNA network. Careful analyses of C. albicans-mtDNA did not reveal detectable amounts of circular DNA molecules. In the present study we addressed the question of how the unit sized linear mtDNA of Candida parapsilosis terminating at both ends with arrays of tandem repeats (mitochondrial telomeres) is replicated. Originally, we expected to find replication intermediates diagnostic of canonical bi-directional replication initiation at the centrally located bi-directional promoter region. However, we found that the linear mtDNA of Candida parapsilosis also employs recombination for replication initiation. The most striking findings were that the mitochondrial telomeres appear to be hot spots for recombination driven replication, and that stable RNA:DNA hybrids, with a potential role in mtDNA replication, are also present in the mtDNA preparations. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Replication Intermediates of the Linear Mitochondrial DNA of Candida parapsilosis Suggest a Common Recombination Based Mechanism for Yeast Mitochondria*

PubMed Central

Gerhold, Joachim M.; Sedman, Tiina; Visacka, Katarina; Slezakova, Judita; Tomaska, Lubomir; Nosek, Jozef; Sedman, Juhan

2014-01-01

Variation in the topology of mitochondrial DNA (mtDNA) in eukaryotes evokes the question if differently structured DNAs are replicated by a common mechanism. RNA-primed DNA synthesis has been established as a mechanism for replicating the circular animal/mammalian mtDNA. In yeasts, circular mtDNA molecules were assumed to be templates for rolling circle DNA-replication. We recently showed that in Candida albicans, which has circular mapping mtDNA, recombination driven replication is a major mechanism for replicating a complex branched mtDNA network. Careful analyses of C. albicans-mtDNA did not reveal detectable amounts of circular DNA molecules. In the present study we addressed the question of how the unit sized linear mtDNA of Candida parapsilosis terminating at both ends with arrays of tandem repeats (mitochondrial telomeres) is replicated. Originally, we expected to find replication intermediates diagnostic of canonical bi-directional replication initiation at the centrally located bi-directional promoter region. However, we found that the linear mtDNA of Candida parapsilosis also employs recombination for replication initiation. The most striking findings were that the mitochondrial telomeres appear to be hot spots for recombination driven replication, and that stable RNA:DNA hybrids, with a potential role in mtDNA replication, are also present in the mtDNA preparations. PMID:24951592

Ultrasensitive detection of nucleic acids and proteins using quartz crystal microbalance and surface plasmon resonance sensors based on target-triggering multiple signal amplification strategy.

PubMed

Sun, Wenbo; Song, Weiling; Guo, Xiaoyan; Wang, Zonghua

2017-07-25

In this study, quartz crystal microbalance (QCM) and surface plasmon resonance (SPR) sensors were combined with template enhanced hybridization processes (TEHP), rolling circle amplification (RCA) and biocatalytic precipitation (BCP) for ultrasensitive detection of DNA and protein. The DNA complementary to the aptamer was released by the specific binding of the aptamer to the target protein and then hybridized with the capture probe and the assistant DNA to form a ternary "Y" junction structure. The initiation chain was generated by the template-enhanced hybridization process which leaded to the rolling circle amplification reaction, and a large number of repeating unit sequences were formed. Hybridized with the enzyme-labeled probes, the biocatalytic precipitation reaction was further carried out, resulting in a large amount of insoluble precipitates and amplifying the detection signal. Under the optimum conditions, detection limits as low as 43 aM for target DNA and 53 aM for lysozyme were achieved. In addition, this method also showed good selectivity and sensitivity in human serum. Copyright © 2017 Elsevier B.V. All rights reserved.

In situ rolling circle amplification detection of Crimean Congo hemorrhagic fever virus (CCHFV) complementary and viral RNA.

PubMed

Andersson, Cecilia; Henriksson, Sara; Magnusson, Karl-Eric; Nilsson, Mats; Mirazimi, Ali

2012-05-10

Crimean Congo hemorrhagic fever virus (CCHFV) is a human pathogen that causes a severe disease with high fatality rate for which there is currently no specific treatment. Knowledge regarding its replication cycle is also highly limited. In this study we developed an in situ technique for studying the different stages during the replication of CCHFV. By integrating reverse transcription, padlock probes, and rolling circle amplification, we were able to detect and differentiate between viral RNA (vRNA) and complementary RNA (cRNA) molecules, and to detect viral protein within the same cell. These data demonstrate that CCHFV nucleocapsid protein (NP) is detectable already at 6 hours post infection in vRNA- and cRNA-positive cells. Confocal microscopy showed that cRNA is enriched and co-localized to a large extent with NP in the perinuclear area, while vRNA has a more random distribution in the cytoplasm with only some co-localize with NP. However, vRNA and cRNA did not appear to co-localize directly. Copyright © 2012 Elsevier Inc. All rights reserved.

Novel readout method for molecular diagnostic assays based on optical measurements of magnetic nanobead dynamics.

PubMed

Donolato, Marco; Antunes, Paula; Bejhed, Rebecca S; Zardán Gómez de la Torre, Teresa; Østerberg, Frederik W; Strömberg, Mattias; Nilsson, Mats; Strømme, Maria; Svedlindh, Peter; Hansen, Mikkel F; Vavassori, Paolo

2015-02-03

We demonstrate detection of DNA coils formed from a Vibrio cholerae DNA target at picomolar concentrations using a novel optomagnetic approach exploiting the dynamic behavior and optical anisotropy of magnetic nanobead (MNB) assemblies. We establish that the complex second harmonic optical transmission spectra of MNB suspensions measured upon application of a weak uniaxial AC magnetic field correlate well with the rotation dynamics of the individual MNBs. Adding a target analyte to the solution leads to the formation of permanent MNB clusters, namely, to the suppression of the dynamic MNB behavior. We prove that the optical transmission spectra are highly sensitive to the formation of permanent MNB clusters and, thereby to the target analyte concentration. As a specific clinically relevant diagnostic case, we detect DNA coils formed via padlock probe recognition and isothermal rolling circle amplification and benchmark against a commercial equipment. The results demonstrate the fast optomagnetic readout of rolling circle products from bacterial DNA utilizing the dynamic properties of MNBs in a miniaturized and low-cost platform requiring only a transparent window in the chip.

Combining isothermal rolling circle amplification and electrochemiluminescence for highly sensitive point mutation detection

NASA Astrophysics Data System (ADS)

Su, Qiang; Zhou, Xiaoming

2008-12-01

Many pathogenic and genetic diseases are associated with changes in the sequence of particular genes. We describe here a rapid and highly efficient assay for the detection of point mutation. This method is a combination of isothermal rolling circle amplification (RCA) and high sensitive electrochemluminescence (ECL) detection. In the design, a circular template generated by ligation upon the recognition of a point mutation on DNA targets was amplified isothermally by the Phi29 polymerase using a biotinylated primer. The elongation products were hybridized with tris (bipyridine) ruthenium (TBR)-tagged probes and detected in a magnetic bead based ECL platform, indicating the mutation occurrence. P53 was chosen as a model for the identification of this method. The method allowed sensitive determination of the P53 mutation from wild-type and mutant samples. The main advantage of RCA-ECL is that it can be performed under isothermal conditions and avoids the generation of false-positive results. Furthermore, ECL provides a faster, more sensitive, and economical option to currently available electrophoresis-based methods.

A valveless rotary microfluidic device for multiplex point mutation identification based on ligation-rolling circle amplification.

PubMed

Heo, Hyun Young; Chung, Soyi; Kim, Yong Tae; Kim, Do Hyun; Seo, Tae Seok

2016-04-15

Genetic variations such as single nucleotide polymorphism (SNP) and point mutations are important biomarkers to monitor disease prognosis and diagnosis. In this study, we developed a novel rotary microfluidic device which can perform multiplex SNP typing on the mutation sites of TP53 genes. The microdevice consists of three glass layers: a channel wafer, a Ti/Pt electrode-patterned resistance temperature detector (RTD) wafer, and a rotary plate in which twelve reaction chambers were fabricated. A series of sample injection, ligation-rolling circle amplification (L-RCA) reaction, and fluorescence detection of the resultant amplicons could be executed by rotating the top rotary plate, identifying five mutation points related with cancer prognosis. The use of the rotary plate eliminates the necessity of microvalves and micropumps to control the microfluidic flow in the channel, simplifying the chip design and chip operation for multiplex SNP detection. The proposed microdevice provides an advanced genetic analysis platform in terms of multiplexity, simplicity, and portability in the fields of biomedical diagnostics. Copyright © 2015 Elsevier B.V. All rights reserved.

In Situ Detection of Anaplasma spp. by DNA Target-Primed Rolling-Circle Amplification of a Padlock Probe and Intracellular Colocalization with Immunofluorescently Labeled Host Cell von Willebrand Factor ▿

PubMed Central

Wamsley, Heather L.; Barbet, Anthony F.

2008-01-01

Endothelial cell culture and preliminary immunofluorescent staining of Anaplasma-infected tissues suggest that endothelial cells may be an in vivo nidus of mammalian infection. To investigate endothelial cells and other potentially cryptic sites of Anaplasma sp. infection in mammalian tissues, a sensitive and specific isothermal in situ technique to detect localized Anaplasma gene sequences by using rolling-circle amplification of circularizable, linear, oligonucleotide probes (padlock probes) was developed. Cytospin preparations of uninfected or Anaplasma-infected cell cultures were examined using this technique. Via fluorescence microscopy, the technique described here, and a combination of differential interference contrast microscopy and von Willebrand factor immunofluorescence, Anaplasma phagocytophilum and Anaplasma marginale were successfully localized in situ within intact cultured mammalian cells. This work represents the first application of this in situ method for the detection of a microorganism and forms the foundation for future applications of this technique to detect, localize, and analyze Anaplasma nucleotide sequences in the tissues of infected mammalian and arthropod hosts and in cell cultures. PMID:18495855

Molecular identification of Neofabraea species associated with bull's-eye rot on apple using rolling-circle amplification of partial EF-1α sequence.

PubMed

Lin, Huijiao; Jiang, Xiang; Yi, Jianping; Wang, Xinguo; Zuo, Ranling; Jiang, Zide; Wang, Weifang; Zhou, Erxun

2018-01-01

A rolling-circle amplification (RCA) method with padlock probes targeted on EF-1α regions was developed for rapid detection of apple bull's-eye rot pathogens, including Neofabraea malicorticis, N. perennans, N. kienholzii, and N. vagabunda (synonym: N. alba). Four padlock probes (PLP-Nm, PLP-Np, PLP-Nk, and PLP-Nv) were designed and tested against 28 samples, including 22 BER pathogen cultures, 4 closely related species, and 2 unrelated species that may cause serious apple decays. The assay successfully identified all the bull's-eye rot pathogenic fungi at the level of species, while no cross-reaction was observed in all target species and no false-positive reaction was observed with all strains used for reference. This study showed that the use of padlock probes and the combination of probe signal amplification by RCA provided an effective and sensitive method for the rapid identification of Neofabraea spp. The method could therefore be a useful tool for monitoring bull's-eye rot pathogens in port quarantine and orchard epidemiological studies.

Sensitive and inexpensive digital DNA analysis by microfluidic enrichment of rolling circle amplified single-molecules

PubMed Central

Kühnemund, Malte; Hernández-Neuta, Iván; Sharif, Mohd Istiaq; Cornaglia, Matteo; Gijs, Martin A.M.

2017-01-01

Abstract Single molecule quantification assays provide the ultimate sensitivity and precision for molecular analysis. However, most digital analysis techniques, i.e. droplet PCR, require sophisticated and expensive instrumentation for molecule compartmentalization, amplification and analysis. Rolling circle amplification (RCA) provides a simpler means for digital analysis. Nevertheless, the sensitivity of RCA assays has until now been limited by inefficient detection methods. We have developed a simple microfluidic strategy for enrichment of RCA products into a single field of view of a low magnification fluorescent sensor, enabling ultra-sensitive digital quantification of nucleic acids over a dynamic range from 1.2 aM to 190 fM. We prove the broad applicability of our analysis platform by demonstrating 5-plex detection of as little as ∼1 pg (∼300 genome copies) of pathogenic DNA with simultaneous antibiotic resistance marker detection, and the analysis of rare oncogene mutations. Our method is simpler, more cost-effective and faster than other digital analysis techniques and provides the means to implement digital analysis in any laboratory equipped with a standard fluorescent microscope. PMID:28077562

Novel rolling circle amplification and DNA origami-based DNA belt-involved signal amplification assay for highly sensitive detection of prostate-specific antigen (PSA).

PubMed

Yan, Juan; Hu, Chongya; Wang, Ping; Liu, Rui; Zuo, Xiaolei; Liu, Xunwei; Song, Shiping; Fan, Chunhai; He, Dannong; Sun, Gang

2014-11-26

Prostate-specific antigen (PSA) is one of the most important biomarkers for the early diagnosis and prognosis of prostate cancer. Although many efforts have been made to achieve significant progress for the detection of PSA, challenges including relative low sensitivity, complicated operation, sophisticated instruments, and high cost remain unsolved. Here, we have developed a strategy combining rolling circle amplification (RCA)-based DNA belts and magnetic bead-based enzyme-linked immunosorbent assay (ELISA) for the highly sensitive and specific detection of PSA. At first, a 96-base circular DNA template was designed and prepared for the following RCA. Single stranded DNA (ssDNA) products from RCA were used as scaffold strand for DNA origami, which was hybridized with three staple strands of DNA. The resulting DNA belts were conjugated with multiple enzymes for signal amplification and then employed to magnetic bead based ELISA for PSA detection. Through our strategy, as low as 50 aM of PSA can be detected with excellent specificity.

Evolution of microstructure, texture and inhibitor along the processing route for grain-oriented electrical steels using strip casting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Hai-Tao, E-mail: liuht@ral.neu.edu.cn; Institute of Research of Iron and Steel, Shasteel, Zhangjiagang 215625, Jiangsu; Yao, Sheng-Jie

2015-08-15

In the present work, a regular grade GO sheet was produced successively by strip casting, hot rolling, normalizing annealing, two-stage cold rolling with intermediate annealing, primary recrystallization annealing, secondary recrystallization annealing and purification. The aim of this paper was to characterize the evolution of microstructure, texture and inhibitor along the new processing route by comprehensive utilization of optical microscopy, X-ray diffraction and transmission electron microscopy. It was found that a fine microstructure with the ferrite grain size range of 7–12 μm could be obtained in the primary recrystallization annealed sheet though a very coarse microstructure was produced in the initialmore » as-cast strip. The main finding was that the “texture memory” effect on Goss texture started on the through-thickness intermediate annealed strip after first cold rolling, which was not similar to the “texture memory” effect on Goss texture starting on the surface layers of the hot rolled strip in the conventional production route. As a result, the origin of Goss nuclei capable of secondary recrystallization lied in the grains already presented in Goss orientation in the intermediate annealed strip after first cold rolling. Another finding was that fine and dispersive inhibitors (mainly AlN) were easy to be produced in the primary recrystallization microstructure due to the initial rapid solidification during strip casting and the subsequent rapid cooling, and the very high temperature reheating usually used before hot rolling in the conventional production route could be avoided. - Highlights: • A regular grade grain-oriented electrical steel was produced. • Evolution of microstructure, texture and inhibitor was characterized. • Origin of Goss nuclei lied in the intermediate annealed strip. • A fine primary recrystallization microstructure could be produced. • Effective inhibitors were easy to be obtained in the new processing route.« less

Going Around On Circles: Mathematics and Computer Art. Part 2.

ERIC Educational Resources Information Center

Gordon, Sheldon P.; Gordon, Florence S.

1984-01-01

Discusses properties of epicycloids. (The easiest way to picture them is to think of a piece of radioactive bubble gum attached to a wheel which is rolling around the outside of a larger wheel.) Includes a computer program (TRS-80 color computer) that will graph any epicycloid with integer values for the radii. (JN)

Biopower and Pedagogy: Local Spaces and Institutional Technologies

ERIC Educational Resources Information Center

Wittman, John

2006-01-01

While sitting on a bench outside the university's museum grappling with his own emotional numbness and inability to comprehend the traumatic events of 9-11, John Wittman watched a group of 4 students circling one of the main buildings on campus with an American flag on the back of the roll bar of a truck. Having thought about the flag-waving…

Sensitive and inexpensive digital DNA analysis by microfluidic enrichment of rolling circle amplified single-molecules.

PubMed

Kühnemund, Malte; Hernández-Neuta, Iván; Sharif, Mohd Istiaq; Cornaglia, Matteo; Gijs, Martin A M; Nilsson, Mats

2017-05-05

Single molecule quantification assays provide the ultimate sensitivity and precision for molecular analysis. However, most digital analysis techniques, i.e. droplet PCR, require sophisticated and expensive instrumentation for molecule compartmentalization, amplification and analysis. Rolling circle amplification (RCA) provides a simpler means for digital analysis. Nevertheless, the sensitivity of RCA assays has until now been limited by inefficient detection methods. We have developed a simple microfluidic strategy for enrichment of RCA products into a single field of view of a low magnification fluorescent sensor, enabling ultra-sensitive digital quantification of nucleic acids over a dynamic range from 1.2 aM to 190 fM. We prove the broad applicability of our analysis platform by demonstrating 5-plex detection of as little as ∼1 pg (∼300 genome copies) of pathogenic DNA with simultaneous antibiotic resistance marker detection, and the analysis of rare oncogene mutations. Our method is simpler, more cost-effective and faster than other digital analysis techniques and provides the means to implement digital analysis in any laboratory equipped with a standard fluorescent microscope. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Diffractometric Detection of Proteins using Microbead-based Rolling Circle Amplification

PubMed Central

Lee, Joonhyung; Icoz, Kutay; Roberts, Ana; Ellington, Andrew D.; Savran, Cagri A.

2010-01-01

We present a robust, sensitive, fluorescent or radio label-free self-assembled optical diffraction biosensor that utilizes rolling circle amplification (RCA) and magnetic microbeads as a signal enhancement method. An aptamer-based sandwich assay was performed on microcontact-printed streptavidin arranged in 15-μm-wide alternating lines, and could specifically capture and detect platelet-derived growth factor B-chain (PDGF-BB). An aptamer served as a template for the ligation of a padlock probe and the circularized probe could in turn be used as a template for RCA. The concatameric RCA product hybridized to biotinylated oligonuclotides which then captured streptavidin-labeled magnetic beads. In consequence, the signal from the captured PDGF-BB was amplified via the concatameric RCA product, and the diffraction gratings on the printed areas produced varying intensities of diffraction modes. The detected diffraction intensity and the density of the microbeads on the surface varied as a function of PDGF-BB concentration. Our results demonstrate a robust biosensing platform that is easy to construct and use, and devoid of fluorescence microscopy. The self-assembled bead patterns allow both a visual analysis of the molecular binding events under an ordinary bright-field microscope and serve as a diffraction grating biosensor. PMID:19947589

Effect of Thermomechanical Processing on Microstructure, Texture Evolution, and Mechanical Properties of Al-Mg-Si-Cu Alloys with Different Zn Contents

NASA Astrophysics Data System (ADS)

Wang, X. F.; Guo, M. X.; Chen, Y.; Zhu, J.; Zhang, J. S.; Zhuang, L. Z.

2017-07-01

The effect of thermomechanical processing on microstructure, texture evolution, and mechanical properties of Al-Mg-Si-Cu alloys with different Zn contents was studied by mechanical properties, microstructure, and texture characterization in the present study. The results show that thermomechanical processing has a significant influence on the evolution of microstructure and texture and on the final mechanical properties, independently of Zn contents. Compared with the T4P-treated (first preaged at 353 K (80 °C) for 12 hours and then naturally aged for 14 days) sheets with high final cold rolling reduction, the T4P-treated sheets with low final cold rolling reduction possess almost identical strength and elongation and higher average r values. Compared with the intermediate annealed sheets with high final cold rolling reduction, the intermediate annealed sheets with low final cold rolling reduction contain a higher number of particles with a smaller size. After solution treatment, in contrast to the sheets with high final cold rolling reduction, the sheets with low final cold rolling reduction possess finer grain structure and tend to form a weaker recrystallization texture. The recrystallization texture may be affected by particle distribution, grain size, and final cold rolling texture. Finally, the visco-plastic self-consistent (VPSC) model was used to predict r values.

Modeling of deformation behavior and texture evolution in magnesium alloy using the intermediate $$\\phi$$-model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Dongsheng; Ahzi, Said; M'Guil, S. M.

2014-01-06

The viscoplastic intermediate phi-model was applied in this work to predict the deformation behavior and texture evolution in a magnesium alloy, an HCP material. We simulated the deformation behavior with different intergranular interaction strengths and compared the predicted results with available experimental results. In this approach, elasticity is neglected and the plastic deformation mechanisms are assumed as a combination of crystallographic slip and twinning systems. Tests are performed for rolling (plane strain compression) of random textured Mg polycrystal as well as for tensile and compressive tests on rolled Mg sheets. Simulated texture evolutions agree well with experimental data. Activities of twinning and slip, predicted by the intermediatemore » $$\\phi$$-model, reveal the strong anisotropic behavior during tension and compression of rolled sheets.« less

A novel ultra-low carbon grain oriented silicon steel produced by twin-roll strip casting

NASA Astrophysics Data System (ADS)

Wang, Yang; Zhang, Yuan-Xiang; Lu, Xiang; Fang, Feng; Xu, Yun-Bo; Cao, Guang-Ming; Li, Cheng-Gang; Misra, R. D. K.; Wang, Guo-Dong

2016-12-01

A novel ultra-low carbon grain oriented silicon steel was successfully produced by strip casting and two-stage cold rolling method. The microstructure, texture and precipitate evolution under different first cold rolling reduction were investigated. It was shown that the as-cast strip was mainly composed of equiaxed grains and characterized by very weak Goss texture ({110}<001>) and λ-fiber (<001>//ND). The coarse sulfides of size 100 nm were precipitated at grain boundaries during strip casting, while nitrides remained in solution in the as-cast strip and the fine AlN particles of size 20-50 nm, which were used as grain growth inhibitors, were formed in intermediate annealed sheet after first cold rolling. In addition, the suitable Goss nuclei for secondary recrystallization were also formed during intermediate annealing, which is totally different from the conventional process that the Goss nuclei originated in the subsurface layer of the hot rolled sheet. Furthermore, the number of AlN inhibitors and the intensity of desirable Goss texture increased with increasing first cold rolling reduction. After secondary recrystallization annealing, very large grains of size 10-40 mm were formed and the final magnetic induction, B8, was as high as 1.9 T.

Transition to chaos of natural convection between two infinite differentially heated vertical plates

NASA Astrophysics Data System (ADS)

Gao, Zhenlan; Sergent, Anne; Podvin, Berengere; Xin, Shihe; Le Quéré, Patrick; Tuckerman, Laurette S.

2013-08-01

Natural convection of air between two infinite vertical differentially heated plates is studied analytically in two dimensions (2D) and numerically in two and three dimensions (3D) for Rayleigh numbers Ra up to 3 times the critical value Rac=5708. The first instability is a supercritical circle pitchfork bifurcation leading to steady 2D corotating rolls. A Ginzburg-Landau equation is derived analytically for the flow around this first bifurcation and compared with results from direct numerical simulation (DNS). In two dimensions, DNS shows that the rolls become unstable via a Hopf bifurcation. As Ra is further increased, the flow becomes quasiperiodic, and then temporally chaotic for a limited range of Rayleigh numbers, beyond which the flow returns to a steady state through a spatial modulation instability. In three dimensions, the rolls instead undergo another pitchfork bifurcation to 3D structures, which consist of transverse rolls connected by counter-rotating vorticity braids. The flow then becomes time dependent through a Hopf bifurcation, as exchanges of energy occur between the rolls and the braids. Chaotic behavior subsequently occurs through two competing mechanisms: a sequence of period-doubling bifurcations leading to intermittency or a spatial pattern modulation reminiscent of the Eckhaus instability.

22. PIN CONNECTION AT JUNCTURE OF INTERMEDIATE VERTICAL WITH BOTTOM ...

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

22. PIN CONNECTION AT JUNCTURE OF INTERMEDIATE VERTICAL WITH BOTTOM CHORD ON PENNSYLVANIA PETIT TRUSS. HYDRAULICALLY FORGED EYES ON ROLLED STOCK. - New River Bridge, Spanning New River at State Route 623, Pembroke, Giles County, VA

Effect of Cold-rolling on Mechanical Properties and Microstructure of an Al-12%Si-0.2%Mg Alloy

NASA Astrophysics Data System (ADS)

Liao, Hengcheng; Cai, Mingdong; Jing, Qiumin; Ding, Ke

2011-11-01

Effect of multi-pass cold-rolling on the mechanical properties and microstructure of a near-eutectic Al-12%Si-0.2%Mg casting alloy was investigated. Optical microscopy, SEM, and TEM were employed to resolve the as-rolled microstructure, and the microstructure of samples after aging treatment. It has been found that Brinell hardness increases considerably with rolling reduction ratio; and further annealing leads to a remarkable drop in hardness. Two mechanisms, namely precipitation hardening and recovery softening, were found to develop simultaneously in the subsequent aging treatment following cold rolling. In contrast, recovery softening dominated the aging of cold-rolled specimen with prior intermediate annealing. Tensile properties were also performed to measure the effect of cold rolling and subsequent aging treatment.

Identification of Prostate Cancer-Specific microDNAs

DTIC Science & Technology

2016-02-01

circular DNA by rolling circle amplification (RCA) and then amplified DNA fragments were subject to deep sequencing. Deep sequencing of the...demonstrate the existence of microDNAs in prostate cancer. We adopted multiple displacement amplification (MDA) with random 2 primers for enriched...prostate cancer cells through multiple displacement amplification and next generation sequencing. R e la ti v e c e ll g ro w th ( % ) 0 20

78 FR 70487 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-26

... Airworthiness Directives; Rolls-Royce plc Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT... turbofan engines. This AD requires removal of certain high-pressure (HP) and intermediate-pressure (IP..., RB211 Trent 768-60, 772-60, and 772B-60 turbofan engines with turbine disc part numbers (P/Ns) and...

77 FR 39157 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-02

... Airworthiness Directives; Rolls-Royce plc Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT...-84, and 980-84 turbofan engines. That AD currently requires inspecting the intermediate-pressure (IP... RR model RB211-Trent 970-84, 970B-84, 972-84, 972B-84, 977-84, 977B-84, and 980-84 turbofan engines...

76 FR 36981 - Airworthiness Directives; Rolls-Royce plc RB211-Trent 500 Series Turbofan Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-24

... Airworthiness Directives; Rolls-Royce plc RB211--Trent 500 Series Turbofan Engines AGENCY: Federal Aviation... condition on an aviation product. The MCAI describes the unsafe condition as: A Trent 500 engine has been found with thermal distress of the Intermediate Pressure (IP) Turbine Nozzle Guide Vanes. The resultant...

Nucleic acid arrays and methods of synthesis

DOEpatents

Sabanayagam, Chandran R.; Sano, Takeshi; Misasi, John; Hatch, Anson; Cantor, Charles

2001-01-01

The present invention generally relates to high density nucleic acid arrays and methods of synthesizing nucleic acid sequences on a solid surface. Specifically, the present invention contemplates the use of stabilized nucleic acid primer sequences immobilized on solid surfaces, and circular nucleic acid sequence templates combined with the use of isothermal rolling circle amplification to thereby increase nucleic acid sequence concentrations in a sample or on an array of nucleic acid sequences.

23. VIEW OF SECTION DRAWINGS. THE SECTION LINES CUT THE ...

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

23. VIEW OF SECTION DRAWINGS. THE SECTION LINES CUT THE BUILDING EAST-WEST. THE ORIGINAL DRAWING HAS BEEN ARCHIVED ON MICROFILM. THE DRAWING WAS REPRODUCED AT THE BEST QUALITY POSSIBLE. LETTERS AND NUMBERS IN THE CIRCLES INDICATE FOOTER AND/OR COLUMN LOCATIONS. - Rocky Flats Plant, Uranium Rolling & Forming Operations, Southeast section of plant, southeast quadrant of intersection of Central Avenue & Eighth Street, Golden, Jefferson County, CO

Identification of Prostate Cancer-Specific microDNAs

DTIC Science & Technology

2014-12-01

displacement amplification (MDA). 2 adopted multiple displacement amplification (MDA) with random primers for enriched circular DNA by rolling circle ... amplification (RCA) (Fig. 1) and then amplified DNA fragments were subject to deep sequencing. Sequence NO of Reads seq 1 184 seq 2 133 seq 3 2407 seq...prostate cancer cells through multiple displacement amplification .  Clone #7 is the top candidate which has been cloned in an expression vector and it

Fluorescence biosensor for inorganic pyrophosphatase activity.

PubMed

Zhang, Ying; Guo, Yajuan; Zhao, Mengmeng; Lin, Cuiying; Lin, Zhenyu; Luo, Fang; Chen, Guonan

2017-02-01

A highly sensitive and selective fluorescence biosensor for inorganic pyrophosphatase (PPase) activity has been developed based on special click ligation trigger hyperbranched rolling circle amplification (CLT-HRCA). Pyrophosphate ion (PPi) can coordinate with Cu 2+ to form stable PPi/Cu 2+ complex and Cu 2+ in the complex cannot be reduced to Cu + . The addition of PPase causes the hydrolysis of PPi into orthophosphate (Pi) and therefore induces the releasing of Cu 2+ from the stable PPi/Cu 2+ complex, and the free Cu 2+ is easily reduced to Cu + by sodium ascorbate. Then Cu + catalyzes the cyclization reaction between the specially designed 5'-azide and 3'-alkyne tagged padlock probes through Cu + catalyzed azide-alkyne cycloaddition (CuAAC), which in turn initiates the hyperbranched rolling circle amplification (HRCA). Given that the CLT-HRCA products contain large amounts of double-stranded DNAs (dsDNAs), the addition of SYBR Green I resulted in the enhanced fluorescence signal. There was a linear relationship between the enhanced fluorescence intensity and the logarithm PPase activity ranging from 0.05 to 25 mU with a detection limit of 0.02 mU. Such proposed biosensor has been successfully applied to screen the potential PPase inhibitors and has accessed the related inhibit ability with high efficiency.

Characterization of Two Novel Polyomaviruses of Birds by Using Multiply Primed Rolling-Circle Amplification of Their Genomes

PubMed Central

Johne, Reimar; Wittig, Walter; Fernández-de-Luco, Daniel; Höfle, Ursula; Müller, Hermann

2006-01-01

Polyomaviruses are small nonenveloped particles with a circular double-stranded genome, approximately 5 kbp in size. The mammalian polyomaviruses mainly cause persistent subclinical infections in their natural nonimmunocompromised hosts. In contrast, the polyomaviruses of birds—avian polyomavirus (APV) and goose hemorrhagic polyomavirus (GHPV)—are the primary agents of acute and chronic disease with high mortality rates in young birds. Screening of field samples of diseased birds by consensus PCR revealed the presence of two novel polyomaviruses in the liver of an Eurasian bullfinch (Pyrrhula pyrrhula griseiventris) and in the spleen of a Eurasian jackdaw (Corvus monedula), tentatively designated as finch polyomavirus (FPyV) and crow polyomavirus (CPyV), respectively. The genomes of the viruses were amplified by using multiply primed rolling-circle amplification and cloned. Analysis of the FPyV and CPyV genome sequences revealed a close relationship to APV and GHPV, indicating the existence of a distinct avian group among the polyomaviruses. The main characteristics of this group are (i) involvement in fatal disease, (ii) the existence of an additional open reading frame in the 5′ region of the late mRNAs, and (iii) a different manner of DNA binding of the large tumor antigen compared to that of the mammalian polyomaviruses. PMID:16537620

Multiplexed protein profiling on microarrays by rolling-circle amplification

PubMed Central

Schweitzer, Barry; Roberts, Scott; Grimwade, Brian; Shao, Weiping; Wang, Minjuan; Fu, Qin; Shu, Quiping; Laroche, Isabelle; Zhou, Zhimin; Tchernev, Velizar T.; Christiansen, Jason; Velleca, Mark; Kingsmore, Stephen F.

2010-01-01

Fluorescent-sandwich immunoassays on microarrays hold appeal for proteomics studies, because equipment and antibodies are readily available, and assays are simple, scalable, and reproducible. The achievement of adequate sensitivity and specificity, however, requires a general method of immunoassay amplification. We describe coupling of isothermal rolling-circle amplification (RCA) to universal antibodies for this purpose. A total of 75 cytokines were measured simultaneously on glass arrays with signal amplification by RCA with high specificity, femtomolar sensitivity, 3 log quantitative range, and economy of sample consumption. A 51-feature RCA cytokine glass array was used to measure secretion from human dendritic cells (DCs) induced by lipopolysaccharide (LPS) or tumor necrosis factor-α (TNF-α). As expected, LPS induced rapid secretion of inflammatory cytokines such as macrophage inflammatory protein (MIP)-1β, interleukin (IL)-8, and interferon-inducible protein (IP)-10. We found that eotaxin-2 and I-309 were induced by LPS; in addition, macrophage-derived chemokine (MDC), thymus and activation-regulated chemokine (TARC), soluble interleukin 6 receptor (sIL-6R), and soluble tumor necrosis factor receptor I (sTNF-RI) were induced by TNF-α treatment. Because microarrays can accommodat ~1,000 sandwich immunoassays of this type, a relatively small number of RCA microarrays seem to offer a tractable approach for proteomic surveys. PMID:11923841

RNase H-assisted RNA-primed rolling circle amplification for targeted RNA sequence detection.

PubMed

Takahashi, Hirokazu; Ohkawachi, Masahiko; Horio, Kyohei; Kobori, Toshiro; Aki, Tsunehiro; Matsumura, Yukihiko; Nakashimada, Yutaka; Okamura, Yoshiko

2018-05-17

RNA-primed rolling circle amplification (RPRCA) is a useful laboratory method for RNA detection; however, the detection of RNA is limited by the lack of information on 3'-terminal sequences. We uncovered that conventional RPRCA using pre-circularized probes could potentially detect the internal sequence of target RNA molecules in combination with RNase H. However, the specificity for mRNA detection was low, presumably due to non-specific hybridization of non-target RNA with the circular probe. To overcome this technical problem, we developed a method for detecting a sequence of interest in target RNA molecules via RNase H-assisted RPRCA using padlocked probes. When padlock probes are hybridized to the target RNA molecule, they are converted to the circular form by SplintR ligase. Subsequently, RNase H creates nick sites only in the hybridized RNA sequence, and single-stranded DNA is finally synthesized from the nick site by phi29 DNA polymerase. This method could specifically detect at least 10 fmol of the target RNA molecule without reverse transcription. Moreover, this method detected GFP mRNA present in 10 ng of total RNA isolated from Escherichia coli without background DNA amplification. Therefore, this method can potentially detect almost all types of RNA molecules without reverse transcription and reveal full-length sequence information.

Ultrasensitive electrochemical detection of nucleic acids by template enhanced hybridization followed with rolling circle amplification.

PubMed

Ji, Hanxu; Yan, Feng; Lei, Jianping; Ju, Huangxian

2012-08-21

An ultrasensitive protocol for electrochemical detection of DNA is designed with quantum dots (QDs) as a signal tag by combining the template enhanced hybridization process (TEHP) and rolling circle amplification (RCA). Upon the recognition of the molecular beacon (MB) to target DNA, the MB hybridizes with assistants and target DNA to form a ternary ''Y-junction''. The target DNA can be dissociated from the structure under the reaction of nicking endonuclease to initiate the next hybridization process. The template enhanced MB fragments further act as the primers of the RCA reaction to produce thousands of repeated oligonucleotide sequences, which can bind with oligonucleotide functionalized QDs. The attached signal tags can be easily read out by square-wave voltammetry after dissolving with acid. Because of the cascade signal amplification and the specific TEHP and RCA reaction, this newly designed protocol provides an ultrasensitive electrochemical detection of DNA down to the attomolar level (11 aM) with a linear range of 6 orders of magnitude (from 1 × 10(-17) to 1 × 10(-11) M) and can discriminate mismatched DNA from perfect matched target DNA with high selectivity. The high sensitivity and specificity make this method a great potential for early diagnosis in gene-related diseases.

Double-probe signal enhancing strategy for toxin aptasensing based on rolling circle amplification.

PubMed

Tong, Ping; Zhao, Wei-Wei; Zhang, Lan; Xu, Jing-Juan; Chen, Hong-Yuan

2012-03-15

On the basis of aptamer-based rolling circle amplification (RCA) and magnetic beads (MBs), a highly sensitive electrochemical method was developed for the determination of Ochratoxin A (OTA). Initially, an amino-modified capture DNA was immobilized onto MBs for the following hybridization with an OTA aptamer and a phosphate labeled padlock DNA. In the presence of OTA, the aptamer would dissociate from the bioconjugate, and the padlock DNA would subsequently hybridize with the capture DNA to form a circular template with the aid of the T4 ligase. Next, capture DNA would act as primer to initiate a linear RCA reaction and hence generate a long tandem repeated sequences by phi29 DNA polymerase and dNTPs. Then, two quantum dots (QDs) labeled DNA probes were tagged on the resulted RCA product to indicate the OTA recognition event by electrochemical readout. This strategy, based on the novel design of OTA-mediated DNA circularization, the combination of RCA and double signal probes introduction, could detect OTA down to the level of 0.2 pg mL(-1) with a dynamic range spanning more than 4 orders of magnitude. The proposed approach is tested to determine OTA in red wines and shows good application potential in real samples. Copyright © 2011 Elsevier B.V. All rights reserved.

Primer Extension Mutagenesis Powered by Selective Rolling Circle Amplification

PubMed Central

Huovinen, Tuomas; Brockmann, Eeva-Christine; Akter, Sultana; Perez-Gamarra, Susan; Ylä-Pelto, Jani; Liu, Yuan; Lamminmäki, Urpo

2012-01-01

Primer extension mutagenesis is a popular tool to create libraries for in vitro evolution experiments. Here we describe a further improvement of the method described by T.A. Kunkel using uracil-containing single-stranded DNA as the template for the primer extension by additional uracil-DNA glycosylase treatment and rolling circle amplification (RCA) steps. It is shown that removal of uracil bases from the template leads to selective amplification of the nascently synthesized circular DNA strand carrying the desired mutations by phi29 DNA polymerase. Selective RCA (sRCA) of the DNA heteroduplex formed in Kunkel's mutagenesis increases the mutagenesis efficiency from 50% close to 100% and the number of transformants 300-fold without notable diversity bias. We also observed that both the mutated and the wild-type DNA were present in at least one third of the cells transformed directly with Kunkel's heteroduplex. In contrast, the cells transformed with sRCA product contained only mutated DNA. In sRCA, the complex cell-based selection for the mutant strand is replaced with the more controllable enzyme-based selection and less DNA is needed for library creation. Construction of a gene library of ten billion members is demonstrated with the described method with 240 nanograms of DNA as starting material. PMID:22355397

21. VIEW OF THE FIRST FLOOR PLAN. THE FIRST FLOOR ...

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

21. VIEW OF THE FIRST FLOOR PLAN. THE FIRST FLOOR WAS USED FOR DEPLETED AND ENRICHED URANIUM FABRICATION. THE ORIGINAL DRAWING HAS BEEN ARCHIVED ON MICROFILM. THE DRAWING WAS REPRODUCED AT THE BEST QUALITY POSSIBLE. LETTERS AND NUMBERS IN THE CIRCLES INDICATE FOOTER AND/OR COLUMN LOCATIONS. - Rocky Flats Plant, Uranium Rolling & Forming Operations, Southeast section of plant, southeast quadrant of intersection of Central Avenue & Eighth Street, Golden, Jefferson County, CO

22. VIEW OF THE SECOND FLOOR PLAN. THE SECOND FLOOR ...

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

22. VIEW OF THE SECOND FLOOR PLAN. THE SECOND FLOOR CONTAINS THE AIR PLENUM ND SOME OFFICE SPACE. THE ORIGINAL DRAWING HAS BEEN ARCHIVED ON MICROFILM. THE DRAWING WAS REPRODUCED AT THE BEST QUALITY POSSIBLE. LETTERS AND NUMBERS IN THE CIRCLES INDICATE FOOTER AND/OR COLUMN LOCATIONS. - Rocky Flats Plant, Uranium Rolling & Forming Operations, Southeast section of plant, southeast quadrant of intersection of Central Avenue & Eighth Street, Golden, Jefferson County, CO

78 FR 5 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-02

... Airworthiness Directives; Rolls-Royce plc Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT...-535E4-C-37 turbofan engines. This AD was prompted by an investigation by RR concluding that certain...- 535E4-B-37; RB211-535E4-B-75; and RB211-535E4-C-37 turbofan engines with intermediate-pressure (IP...

Subcellular Localization and Rolling Circle Replication of Peach Latent Mosaic Viroid: Hallmarks of Group A Viroids

PubMed Central

Bussière, F.; Lehoux, J.; Thompson, D. A.; Skrzeczkowski, L. J.; Perreault, J.-P.

1999-01-01

We characterized the peach latent mosaic viroid (PLMVd) replication intermediates that accumulate in infected peach leaves and determined the tissue and subcellular localization of the RNA species. Using in situ hybridization, we showed that PLMVd strands of both plus and minus polarities concentrate in the cells forming the palisade parenchyma. At the cellular level, PLMVd was found to accumulate predominantly in chloroplasts. Northern blot analyses demonstrated that PLMVd replicates via a symmetric mode involving the accumulation of both circular and linear monomeric strands of both polarities. No multimeric conformer was detected, indicating that both strands self-cleave efficiently via their hammerhead sequences. Dot blot hybridizations revealed that PLMVd strands of both polarities accumulate equally but that the relative concentrations vary by more than 50-fold between peach cultivars. Taken together these results establish two hallmarks for the classification of viroids. Group A viroids (e.g., PLMVd), which possess hammerhead structures, replicate in the chloroplasts via the symmetric mode. By contrast, group B viroids, which share a conserved central region, replicate in the nucleus via an asymmetric mechanism. This is an important difference between self-cleaving and non-self-cleaving viroids, and the implications for the evolutionary origin and replication are discussed. PMID:10400727

An aptasensor for staphylococcus aureus based on nicking enzyme amplification reaction and rolling circle amplification.

PubMed

Xu, Jingguo; Guo, Jia; Maina, Sarah Wanjiku; Yang, Yumeng; Hu, Yimin; Li, Xuanxuan; Qiu, Jiarong; Xin, Zhihong

2018-05-15

An ultra-sensitive aptamer-based biosensor for the detection of staphylococcus aureus was established by adopting the nicking enzyme amplification reaction (NEAR) and the rolling circle amplification (RCA) technologies. Aptamer-probe (AP), containing an aptamer and a probe sequence, was developed to act as the recognition unit of the biosensor, which was specifically bound to S. aureus. The probe was released from AP and initiated into the subsequent DNA amplification reactions where S. aureus was present, converting the detection of S. aureus to the investigation of probe oligonucleotide. The RCA amplification products contained a G-quadruplex motif and formed a three dimensional structure in presence of hemin. The G4/hemin complex showed horseradish peroxidase (HRP)-mimic activity and catalyzed the chemiluminescence reaction of luminol mediated by H 2 O 2 . The results showed that the established biosensor could detect S. aureus specifically with a good linear correlation at 5-10 4  CFU/mL. The signal values based on NEAR-RCA two-step cycle were boosted acutely, much higher than that relied on one-cycle magnification. The limit of detection (LoD) was determined to be as low as 5 CFU/mL. The established aptasensor exhibited a good discrimination of living against dead S. aureus, and can be applied to detect S. aureus in the food industry. Copyright © 2018 Elsevier Inc. All rights reserved.

Terahertz spectroscopy for the isothermal detection of bacterial DNA by magnetic bead-based rolling circle amplification.

PubMed

Yang, Xiang; Yang, Ke; Zhao, Xiang; Lin, Zhongquan; Liu, Zhiyong; Luo, Sha; Zhang, Yang; Wang, Yunxia; Fu, Weiling

2017-12-04

The demand for rapid and sensitive bacterial detection is continuously increasing due to the significant requirements of various applications. In this study, a terahertz (THz) biosensor based on rolling circle amplification (RCA) was developed for the isothermal detection of bacterial DNA. The synthetic bacterium-specific sequence of 16S rDNA hybridized with a padlock probe (PLP) that contains a sequence fully complementary to the target sequence at the 5' and 3' ends. The linear PLP was circularized by ligation to form a circular PLP upon recognition of the target sequence; then the capture probe (CP) immobilized on magnetic beads (MBs) acted as a primer to initialize RCA. As DNA molecules are much less absorptive than water molecules in the THz range, the RCA products on the surface of the MBs cause a significant decrease in THz absorption, which can be sensitively probed by THz spectroscopy. Our results showed that 0.12 fmol of synthetic bacterial DNA and 0.05 ng μL -1 of genomic DNA could be effectively detected using this assay. In addition, the specificity of this strategy was demonstrated by its low signal response to interfering bacteria. The proposed strategy not only represents a new method for the isothermal detection of the target bacterial DNA but also provides a general methodology for sensitive and specific DNA biosensing using THz spectroscopy.

Rapid Identification and Differentiation of Trichophyton Species, Based on Sequence Polymorphisms of the Ribosomal Internal Transcribed Spacer Regions, by Rolling-Circle Amplification▿

PubMed Central

Kong, Fanrong; Tong, Zhongsheng; Chen, Xiaoyou; Sorrell, Tania; Wang, Bin; Wu, Qixuan; Ellis, David; Chen, Sharon

2008-01-01

DNA sequencing analyses have demonstrated relatively limited polymorphisms within the fungal internal transcribed spacer (ITS) regions among Trichophyton spp. We sequenced the ITS region (ITS1, 5.8S, and ITS2) for 42 dermatophytes belonging to seven species (Trichophyton rubrum, T. mentagrophytes, T. soudanense, T. tonsurans, Epidermophyton floccosum, Microsporum canis, and M. gypseum) and developed a novel padlock probe and rolling-circle amplification (RCA)-based method for identification of single nucleotide polymorphisms (SNPs) that could be exploited to differentiate between Trichophyton spp. Sequencing results demonstrated intraspecies genetic variation for T. tonsurans, T. mentagrophytes, and T. soudanense but not T. rubrum. Signature sets of SNPs between T. rubrum and T. soudanense (4-bp difference) and T. violaceum and T. soudanense (3-bp difference) were identified. The RCA assay correctly identified five Trichophyton species. Although the use of two “group-specific” probes targeting both the ITS1 and the ITS2 regions were required to identify T. soudanense, the other species were identified by single ITS1- or ITS2-targeted species-specific probes. There was good agreement between ITS sequencing and the RCA assay. Despite limited genetic variation between Trichophyton spp., the sensitive, specific RCA-based SNP detection assay showed potential as a simple, reproducible method for the rapid (2-h) identification of Trichophyton spp. PMID:18234865

Homogeneous and label-free detection of microRNAs using bifunctional strand displacement amplification-mediated hyperbranched rolling circle amplification.

PubMed

Zhang, Li-rong; Zhu, Guichi; Zhang, Chun-yang

2014-07-01

MicroRNAs (miRNAs) are an emerging class of biomarkers and therapeutic targets for various diseases including cancers. Here, we develop a homogeneous and label-free method for sensitive detection of let-7a miRNA based on bifunctional strand displacement amplification (SDA)-mediated hyperbranched rolling circle amplification (HRCA). The binding of target miRNA with the linear template initiates the bifunctional SDA reaction, generating two different kinds of triggers which can hybridize with the linear template to initiate new rounds of SDA reaction for the production of more and more triggers. In the meantime, the released two different kinds of triggers can function as the first and the second primers, respectively, to initiate the HRCA reaction whose products can be simply monitored by a standard fluorometer with SYBR Green I as the fluorescent indicator. The proposed method exhibits high sensitivity with a detection limit of as low as 1.8 × 10(-13) M and a large dynamic range of 5 orders of magnitude from 0.1 pM to 10 nM, and it can even discriminate the single-base difference among the miRNA family members. Moreover, this method can be used to analyze the total RNA samples from the human lung tissues and might be further applied for sensitive detection of various proteins, small molecules, and metal ions in combination with specific aptamers.

Cascade Signal Amplification Based on Copper Nanoparticle-Reported Rolling Circle Amplification for Ultrasensitive Electrochemical Detection of the Prostate Cancer Biomarker.

PubMed

Zhu, Ye; Wang, Huijuan; Wang, Lin; Zhu, Jing; Jiang, Wei

2016-02-03

An ultrasensitive and highly selective electrochemical assay was first attempted by combining the rolling circle amplification (RCA) reaction with poly(thymine)-templated copper nanoparticles (CuNPs) for cascade signal amplification. As proof of concept, prostate specific antigen (PSA) was selected as a model target. Using a gold nanoparticle (AuNP) as a carrier, we synthesized the primer-AuNP-aptamer bioconjugate for signal amplification by increasing the primer/aptamer ratio. The specific construction of primer-AuNP-aptamer/PSA/anti-PSA sandwich structure triggered the effective RCA reaction, in which thousands of tandem poly(thymine) repeats were generated and directly served as the specific templates for the subsequent CuNP formation. The signal readout was easily achieved by dissolving the RCA product-templated CuNPs and detecting the released copper ions with differential pulse stripping voltammetry. Because of the designed cascade signal amplification strategy, the newly developed method achieved a linear range of 0.05-500 fg/mL, with a remarkable detection limit of 0.020 ± 0.001 fg/mL PSA. Finally, the feasibility of the developed method for practical application was investigated by analyzing PSA in the real clinical human serum samples. The ultrasensitivity, specificity, convenience, and capability for analyzing the clinical samples demonstrate that this method has great potential for practical disease diagnosis applications.

A cascade signal amplification strategy for surface enhanced Raman spectroscopy detection of thrombin based on DNAzyme assistant DNA recycling and rolling circle amplification.

PubMed

Gao, Fenglei; Du, Lili; Tang, Daoquan; Lu, Yao; Zhang, Yanzhuo; Zhang, Lixian

2015-04-15

A sensitive protocol for surface enhanced Raman spectroscopy (SERS) detection of thrombin is designed with R6G-Ag NPs as a signal tag by combining DNAzyme assistant DNA recycling and rolling circle amplification (RCA). Molecular beacon (MB) as recognition probe immobilizes on the glass slides and performs the amplification procedure. After thrombin-induced structure-switching DNA hairpins of probe 1, the DNAzyme is liberated from the caged structure, which hybridizes with the MB for cleavage of the MB in the presence of cofactor Zn(2+) and initiates the DNA recycling process, leading to the cleavage of a large number of MB and the generation of numerous primers for triggering RCA reaction. The long amplified RCA product which contained hundreds of tandem-repeat sequences, which can bind with oligonucleotide functionalized Ag NPs reporters. The attached signal tags can be easily read out by SERS. Because of the cascade signal amplification, these newly designed protocols provides a sensitive SERS detection of thrombin down to the femolar level (2.3fM) with a linear range of 5 orders of magnitude (from 10(-14) to 10(-9)M) and have high selectivity toward its target protein. The proposed method is expected to be a good clinical tool for the diagnosis of a thrombotic disease. Copyright © 2014 Elsevier B.V. All rights reserved.

Note on the stability of viscous roll waves

NASA Astrophysics Data System (ADS)

Barker, Blake; Johnson, Mathew A.; Noble, Pascal; Rodrigues, Luis Miguel; Zumbrun, Kevin

2017-02-01

In this note, we announce a complete classification of the stability of periodic roll-wave solutions of the viscous shallow water equations, from their onset at Froude number F ≈ 2 up to the infinite Froude limit. For intermediate Froude numbers, we obtain numerically a particularly simple power-law relation between F and the boundaries of the region of stable periods, which appears potentially useful in hydraulic engineering applications. In the asymptotic regime F → 2 (onset), we provide an analytic expression of the stability boundaries, whereas in the limit F → ∞, we show that roll waves are always unstable.

Rolling Circle Transcription of Ribozymes Targeted to ras and mdr-1

DTIC Science & Technology

2001-09-01

ssDNA) to direct transcription of an tion-PCR, and recyclization were carried out to optimize active hammerhead ribozyme in E. coli cells. transcription...transcription I hammerhead ribozyme I in vitro selection and 12.5 units/ml RNase inhibitor (Promega), in a total reaction volume of 15 tk1. After a...sequence encoding a ssDNA, and splint ssDNA were ethanol-precipitated and used as hammerhead ribozyme . templates to begin the next round of in vitro

20. VIEW OF THE BASEMENT FLOOR PLAN. THE BASEMENT AREA ...

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

20. VIEW OF THE BASEMENT FLOOR PLAN. THE BASEMENT AREA INCLUDES A UTILITY ROOM, PROCESS WASTE STORAGE AND MAINTENANCE AREAS, AND THE ENTRANCE TO AN UNDERGROUND TUNNEL LEADING TO BUILDING 881. THE ORIGINAL DRAWING HAS BEEN ARCHIVED ON MICROFILM. THE DRAWING WAS REPRODUCED AT THE BEST QUALITY POSSIBLE. LETTERS AND NUMBERS IN THE CIRCLES INDICATE FOOTER AND/OR COLUMN LOCATIONS. - Rocky Flats Plant, Uranium Rolling & Forming Operations, Southeast section of plant, southeast quadrant of intersection of Central Avenue & Eighth Street, Golden, Jefferson County, CO

Mechanism for circularization of linear DNAs: circular parvovirus MVM DNA is formed by a "noose" sliding in a "lasso"-like DNA structure.

PubMed

Bratosin, S; Laub, O; Tal, J; Aloni, Y

1979-09-01

During an electron-microscopic survey with the aim of identifying the parvovirus MVM transcription template, we observed previously unidentified structures of MVM DNA in lysates of virus-infected cells. These included double-stranded "lasso"-like structures and relaxed circles. Both structures were of unit length MVM DNA, indicating that they were not intermediates formed during replication; they each represented about 5% of the total nuclear MVM DNA. The proportion of these structures was unchanged after digestion with sodium dodecyl sulfate/Pronase and RNase and after mild denaturation treatment. Cleavage of the "lasso" structures with EcoRI restriction endonuclease indicated that the "noose" part of the "lasso" structure is located on the 5' side of the genomic single-stranded MVM DNA. A model is presented for the molecular nature of the circularization process of MVM DNA in which the "lasso" structures are identified as intermediates during circle formation. This model proposes a mechanism for circularization of linear DNAs.

An investigation into the design and performance of an automatic shape control system for a Sendzimir cold rolling mill

NASA Astrophysics Data System (ADS)

Dutton, Kenneth

Shape (or flatness) control for rolled steel strip is becoming increasingly important as customer requirements become more stringent. Automatic shape control is now more or less mandatory on all new four-high cold mills, but no comprehensive scheme yet exists on a Sendzimir mill. This is due to the complexity of the control system design on such a mill, where many more degrees of freedom for control exist than is the case with the four-high mills.The objective of the current work is to develop, from first principles, such a system; including automatic control of the As-U-Roll and first intermediate roll actuators in response to the measured strip shape. This thesis concerns itself primarily with the As-U-Roll control system. The material presented is extremely wide-ranging. Areas covered include the development of original static and dynamic mathematical models of the mill systems, and testing of the plant by data-logging to tune these models. A basic control system philosophy proposed by other workers is modified and developed to suit the practical system requirements and the data provided by the models. The control strategy is tested by comprehensive multivariable simulation studies. Finally, details are given of the practical problems faced when installing the system on the plant. These include problems of manual control inter-action bumpless transfer and integral desaturation.At the time of presentation of the thesis, system commissioning is still in progress and production results are therefore not yet available. Nevertheless, the simulation studies predict a successful outcome, although performance is expected to be limited until the first intermediate roll actuators are eventually included in the scheme also.

Roll Angle System (RAS) for the High-Energy Solar Spectroscopic Imager HESSI

NASA Astrophysics Data System (ADS)

Henneck, Reinhold; Bialkowski, Jacek; Burri, F.; Fivian, M.; Hajdas, W.; Mchedlishvili, A.; Ming, P.; Thomsen, Knud; Welte, J.; Zehnder, Alex; Dettwyler, M.; Buerki, F.; Hurford, Gordon J.; Curtis, Dave W.; Pankow, Dave

1999-10-01

The purpose of the HESSI RAS is to provide information on the roll angle of the rotation spacecraft. Precise knowledge of the roll angle is a necessary ingredient for image reconstruction. The RAS is a continuously operating star scanner that points out radially and observes stars at 75 degrees from the Sun direction using a commercial lens and a fast CCD. The passage of a star image over the CCD charges one or several pixels above threshold and the timing of this signal defines the roll angle, once the star has been identified by comparing its pixel position and amplitude with a star map. Roll angles at intermediate times are inferred by assuming uniform rotation. With a limiting star magnitude of mv equals 3 we expect to observe at least 1 star per revolution over 1 year; on the average we will detect about 10 stars/revolution.

Controlled rolling process for dual phase steels and application to rod, wire, sheet and other shapes

DOEpatents

Thomas, G.; Ahn, J.H.; Kim, N.J.

1986-10-28

An improved, energy efficient, hot rolling method for direct production of cold formable dual-phase steel is provided. The steel is heated to completely austenitize it and then continuously hot rolled and cooled down into the ferrite-austenite two phase region to a temperature which is just below the effective Ar[sub 3] temperature. The hot rolled steel is then rapidly quenched to provide an alloy containing strong, tough lath martensite (fibers) in a ductile soft ferrite matrix. The method is particularly useful for providing rods in which form the alloy is capable of being drawn into high strength wire or the like in a cold drawing operation without any intermediate annealing or patenting, and has excellent strength, ductility and fatigue characteristics. 3 figs.

Controlled rolling process for dual phase steels and application to rod, wire, sheet and other shapes

DOEpatents

Thomas, Gareth; Ahn, Jae-Hwan; Kim, Nack-Joon

1986-01-01

An improved, energy efficient, hot rolling method for direct production of cold formable dual-phase steel is provided. The steel is heated to completely austenitize it and then continuously hot rolled and cooled down into the ferrite-austenite two phase region to a temperature which is just below the effective Ar.sub.3 temperature. The hot rolled steel is then rapidly quenched to provide an alloy containing strong, tough lath martensite (fibers) in a ductile soft ferrite matrix. The method is particularly useful for providing rods in which form the alloy is capable of being drawn into high strength wire or the like in a cold drawing operation without any intermediate annealing or patenting, and has excellent strength, ductility and fatigue characteristics.

Rapid Identification of Pseudallescheria and Scedosporium Strains by Using Rolling Circle Amplification

PubMed Central

Lackner, Michaela; Najafzadeh, Mohammad Javad; Sun, Jiufeng; Lu, Qiaoyun

2012-01-01

The Pseudallescheria boydii complex, comprising environmental pathogens with Scedosporium anamorphs, has recently been subdivided into five main species: Scedosporium dehoogii, S. aurantiacum, Pseudallescheria minutispora, P. apiosperma, and P. boydii, while the validity of some other taxa is being debated. Several Pseudallescheria and Scedosporium species are indicator organisms of pollution in soil and water. Scedosporium dehoogii in particular is enriched in soils contaminated by aliphatic hydrocarbons. In addition, the fungi may cause life-threatening infections involving the central nervous system in severely impaired patients. For screening purposes, rapid and economic tools for species recognition are needed. Our aim is to establish rolling circle amplification (RCA) as a screening tool for species-specific identification of Pseudallescheria and Scedosporium. With this aim, a set of padlock probes was designed on the basis of the internal transcribed spacer (ITS) region, differing by up to 13 fixed mutations. Padlock probes were unique as judged from sequence comparison by BLAST search in GenBank and in dedicated research databases at CBS (Centraalbureau voor Schimmelcultures Fungal Biodiversity Centre). RCA was applied as an in vitro tool, tested with pure DNA amplified from cultures. The species-specific padlock probes designed in this study yielded 100% specificity. The method presented here was found to be an attractive alternative to identification by restriction fragment length polymorphism (RFLP) or sequencing. The rapidity (<1 day), specificity, and low costs make RCA a promising screening tool for environmentally and clinically relevant fungi. PMID:22057865

Rapid identification of Pseudallescheria and Scedosporium strains by using rolling circle amplification.

PubMed

Lackner, Michaela; Najafzadeh, Mohammad Javad; Sun, Jiufeng; Lu, Qiaoyun; Hoog, G Sybren de

2012-01-01

The Pseudallescheria boydii complex, comprising environmental pathogens with Scedosporium anamorphs, has recently been subdivided into five main species: Scedosporium dehoogii, S. aurantiacum, Pseudallescheria minutispora, P. apiosperma, and P. boydii, while the validity of some other taxa is being debated. Several Pseudallescheria and Scedosporium species are indicator organisms of pollution in soil and water. Scedosporium dehoogii in particular is enriched in soils contaminated by aliphatic hydrocarbons. In addition, the fungi may cause life-threatening infections involving the central nervous system in severely impaired patients. For screening purposes, rapid and economic tools for species recognition are needed. Our aim is to establish rolling circle amplification (RCA) as a screening tool for species-specific identification of Pseudallescheria and Scedosporium. With this aim, a set of padlock probes was designed on the basis of the internal transcribed spacer (ITS) region, differing by up to 13 fixed mutations. Padlock probes were unique as judged from sequence comparison by BLAST search in GenBank and in dedicated research databases at CBS (Centraalbureau voor Schimmelcultures Fungal Biodiversity Centre). RCA was applied as an in vitro tool, tested with pure DNA amplified from cultures. The species-specific padlock probes designed in this study yielded 100% specificity. The method presented here was found to be an attractive alternative to identification by restriction fragment length polymorphism (RFLP) or sequencing. The rapidity (<1 day), specificity, and low costs make RCA a promising screening tool for environmentally and clinically relevant fungi.

Exploitation of rolling circle amplification for the construction of large phage-display antibody libraries.

PubMed

Shahsavarian, Melody A; Le Minoux, Damien; Matti, Kalyankumar M; Kaveri, Srini; Lacroix-Desmazes, Sébastien; Boquet, Didier; Friboulet, Alain; Avalle, Bérangère; Padiolleau-Lefèvre, Séverine

2014-05-01

Phage display antibody libraries have proven to have a significant role in the discovery of therapeutic antibodies and polypeptides with desired biological and physicochemical properties. Obtaining a large and diverse phage display antibody library, however, is always a challenging task. Various steps of this technique can still undergo optimization in order to obtain an efficient library. In the construction of a single chain fragment variable (scFv) phage display library, the cloning of the scFv fragments into a phagemid vector is of crucial importance. An efficient restriction enzyme digestion of the scFv DNA leads to its proper ligation with the phagemid followed by its successful cloning and expression. Here, we are reporting a different approach to enhance the efficiency of the restriction enzyme digestion step. We have exploited rolling circle amplification (RCA) to produce a long strand of DNA with tandem repeats of scFv sequences, which is found to be highly susceptible to restriction digestion. With this important modification, we are able to construct a large phage display antibody library of naive SJL/J mice. The size of the library is estimated as ~10(8) clones. The number of clones containing a scFv fragment is estimated at 90%. Hence, the present results could considerably aid the utilization of the phage-display technique in order to get an efficiently large antibody library. Copyright © 2014 Elsevier B.V. All rights reserved.

Reactive oxygen species regulate DNA copy number in isolated yeast mitochondria by triggering recombination-mediated replication.

PubMed

Hori, Akiko; Yoshida, Minoru; Shibata, Takehiko; Ling, Feng

2009-02-01

Mitochondrial DNA (mtDNA) encodes proteins that are essential for cellular ATP production. Reactive oxygen species (ROS) are respiratory byproducts that damage mtDNA and other cellular components. In Saccharomyces cerevisiae, the oxidized base excision-repair enzyme Ntg1 introduces a double-stranded break (DSB) at the mtDNA replication origin ori5; this DSB initiates the rolling-circle mtDNA replication mediated by the homologous DNA pairing protein Mhr1. Thus, ROS may play a role in the regulation of mtDNA copy number. Here, we show that the treatment of isolated mitochondria with low concentrations of hydrogen peroxide increased mtDNA copy number in an Ntg1- and Mhr1-dependent manner. This treatment elevated the DSB levels at ori5 of hypersuppressive [rho(-)] mtDNA only if Ntg1 was active. In vitro Ntg1-treatment of hypersuppressive [rho(-)] mtDNA extracted from hydrogen peroxide-treated mitochondria revealed increased oxidative modifications at ori5 loci. We also observed that purified Ntg1 created breaks in single-stranded DNA harboring oxidized bases, and that ori5 loci have single-stranded character. Furthermore, chronic low levels of hydrogen peroxide increased in vivo mtDNA copy number. We therefore propose that ROS act as a regulator of mtDNA copy number, acting through the Mhr1-dependent initiation of rolling-circle replication promoted by Ntg1-induced DSB in the single-stranded regions at ori5.

Precise determination, cross-recognition, and functional analysis of the double-strand origins of the rolling-circle replication plasmids in haloarchaea.

PubMed

Zhou, Ligang; Zhou, Meixian; Sun, Chaomin; Han, Jing; Lu, Qiuhe; Zhou, Jian; Xiang, Hua

2008-08-01

The precise nick site in the double-strand origin (DSO) of pZMX201, a 1,668-bp rolling-circle replication (RCR) plasmid from the haloarchaeon Natrinema sp. CX2021, was determined by electron microscopy and DSO mapping. In this plasmid, DSO nicking occurred between residues C404 and G405 within a heptanucleotide sequence (TCTC/GGC) located in the stem region of an imperfect hairpin structure. This nick site sequence was conserved among the haloarchaeal RCR plasmids, including pNB101, suggesting that the DSO nick site might be the same for all members of this plasmid family. Interestingly, the DSOs of pZMX201 and pNB101 were found to be cross-recognized in RCR initiation and termination in a hybrid plasmid system. Mutation analysis of the DSO from pZMX201 (DSO(Z)) in this hybrid plasmid system revealed that: (i) the nucleotides in the middle of the conserved TCTCGGC sequence play more-important roles in the initiation and termination process; (ii) the left half of the hairpin structure is required for initiation but not for termination; and (iii) a 36-bp sequence containing TCTCGGC and the downstream sequence is essential and sufficient for termination. In conclusion, these haloarchaeal plasmids, with novel features that are different from the characteristics of both single-stranded DNA phages and bacterial RCR plasmids, might serve as a good model for studying the evolution of RCR replicons.

Comparison of the rolling circle amplification and ligase-dependent reaction methods for the identification of opportunistic Exophiala species.

PubMed

Kaplan, Engin; Ilkit, Macit; de Hoog, G Sybren

2017-10-26

We developed two ligase-dependent probe amplification assays based on rolling circle amplification (RCA) and the ligase-dependent reaction (LDR) to differentiate species of Exophiala targeting the rDNA internal transcribed spacer region. We focused on Exophiala dermatitidis and E. phaeomuriformis, two opportunistic inhabitants of indoor wet cells, and further detected E. heteromorpha, E. xenobiotica, and E. crusticola; 57 reference isolates representing the five species were tested. Depending on the RCA probes used, the sensitivity was 100%, and the specificity ranged from 3.7% to 88.6% (median: 46.1%). In contrast, the sensitivity and specificity of the LDR probes targeting the same isolates were 88.6-100% (median: 95.8%) and 95.4-100% (median: 97.7%), respectively. We analyzed 198 additional environmental isolates representing the same Exophiala species. Overall, the sensitivity and specificity of LDR ranged from 89.7% to 100% (median: 94.1%) and from 93.9% to 100% (median: 96.9%), respectively. The assessment of performance and validation of LDR probes using SYBR Green quantitative polymerase chain reaction revealed high reproducibility and an acceptable range limit, in line with the guidelines of the European Network of GMO Laboratories. In conclusion, the LDR assay was more reliable and less expensive than RCA for species-level identification of Exophiala isolates. © The Author 2017. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

ELECTRIC PHASE ANGLE OF CELL MEMBRANES

PubMed Central

Cole, Kenneth S.

1932-01-01

From the theory of an electric network containing any combination of resistances and a single variable impedance element having a constant phase angle independent of frequency, it is shown that the graph of the terminal series reactance against the resistance is an arc of a circle with the position of the center depending upon the phase angle of the variable element. If it be assumed that biological systems are equivalent to such a network, the hypotheses are supported at low and intermediate frequencies by data on red blood cells, muscle, nerve, and potato. For some tissues there is a marked divergence from the circle at high frequencies, which is not interpreted. PMID:19872673

Effect of double vacuum melting and retained austenite on rolling-element fatigue life of AMS 5749 bearing steel

NASA Technical Reports Server (NTRS)

Parker, R. J.; Hodder, R. S.

1977-01-01

AMS 5749 steel combines the tempering, hot hardness, and hardness retention characteristics of AISI M-50 steel with the corrosion and oxidation resistance of AISI 440C stainless steel. The five-ball fatigue tester was used to evaluate the rolling-element fatigue life of AMS 5749. Double vacuum melting (vacuum induction melting plus vacuum arc remelting, VIM-VAR) produced AMS 5749 material with a rolling-element fatigue life at least 14 times that of vacuum induction melting alone. The VIM-VAR AMS 5749 steel balls gave lives from 6 to 12 times greater than VIM-VAR AISI M-50 steel balls. The highest level of retained austenite, 14.6 percent, was significantly detrimental to rolling-element fatigue life relative to the intermediate level of 11.1 percent.

Investigation on papillomavirus infection in dromedary camels in Al-Ahsa, Saudi Arabia

PubMed Central

Khalafalla, Abdelmalik Ibrahim; Ramadan, Ramadan Omer; Rector, Annabel; Barakat, Seif

2017-01-01

We investigated two outbreaks of papillomatosis between 2013 and 2015 in Al Ahsa region of eastern Saudi Arabia involving fourteen dromedary camels. The disease affected both young and adult animals and occurred in coincidence with demodectic mange infestation. Diagnosis was made based on gross and histopathological characteristics of the wart lesion and was confirmed by PCR. Rolling circle amplification followed by degenerate primer PCR and sequencing of the amplicons revealed the presence of both Camelus dromedarius papillomavirus types 1 and 2, previously identified in infected dromedaries in Sudan. PMID:28717601

31. RW Meyer Sugar Mill: 18761889. Threeroll sugar mill: oneton ...

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

31. RW Meyer Sugar Mill: 1876-1889. Three-roll sugar mill: one-ton daily processing capacity. Manufactured by Edwin Maw, Liverpool, England, ca. 1855-1870. View: View down at the mill from top of the mill's circular masonry enclosure. Mill animals circling above the mill, on top of the enclosure, dragged booms radiating from the drive shaft to power the mill. The drive-shaft is no longer in its upright positon but is lying next to the mill in the foreground. - R. W. Meyer Sugar Mill, State Route 47, Kualapuu, Maui County, HI

30. RW Meyer Sugar Mill: 18761889. Threeroll sugar mill: oneton ...

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

30. RW Meyer Sugar Mill: 1876-1889. Three-roll sugar mill: one-ton daily processing capacity. Manufactured by Edwin Maw, Liverpool, England, ca. 1885-1870. View: Masonry-lined passage-way leading to the mill at the center of its circular masonry enclosure. The passageway permitted cane to be carried to the mill and cane trash (bagasse) to be carried away. Bridges over the passageways, no longer in place, permitted the mill animals to circle and power the mill from above. - R. W. Meyer Sugar Mill, State Route 47, Kualapuu, Maui County, HI

Lateral-Directional Eigenvector Flying Qualities Guidelines for High Performance Aircraft

NASA Technical Reports Server (NTRS)

Davidson, John B.; Andrisani, Dominick, II

1996-01-01

This report presents the development of lateral-directional flying qualities guidelines with application to eigenspace (eigenstructure) assignment methods. These guidelines will assist designers in choosing eigenvectors to achieve desired closed-loop flying qualities or performing trade-offs between flying qualities and other important design requirements, such as achieving realizable gain magnitudes or desired system robustness. This has been accomplished by developing relationships between the system's eigenvectors and the roll rate and sideslip transfer functions. Using these relationships, along with constraints imposed by system dynamics, key eigenvector elements are identified and guidelines for choosing values of these elements to yield desirable flying qualities have been developed. Two guidelines are developed - one for low roll-to-sideslip ratio and one for moderate-to-high roll-to-sideslip ratio. These flying qualities guidelines are based upon the Military Standard lateral-directional coupling criteria for high performance aircraft - the roll rate oscillation criteria and the sideslip excursion criteria. Example guidelines are generated for a moderate-to-large, an intermediate, and low value of roll-to-sideslip ratio.

E-selectin engages PSGL-1 and CD44 through a common signaling pathway to induce integrin alphaLbeta2-mediated slow leukocyte rolling.

PubMed

Yago, Tadayuki; Shao, Bojing; Miner, Jonathan J; Yao, Longbiao; Klopocki, Arkadiusz G; Maeda, Kenichiro; Coggeshall, K Mark; McEver, Rodger P

2010-07-22

In inflamed venules, neutrophils rolling on E-selectin induce integrin alpha(L)beta(2)-dependent slow rolling on intercellular adhesion molecule-1 by activating Src family kinases (SFKs), DAP12 and Fc receptor-gamma (FcRgamma), spleen tyrosine kinase (Syk), and p38. E-selectin signaling cooperates with chemokine signaling to recruit neutrophils into tissues. Previous studies identified P-selectin glycoprotein ligand-1 (PSGL-1) as the essential E-selectin ligand and Fgr as the only SFK that initiate signaling to slow rolling. In contrast, we found that E-selectin engagement of PSGL-1 or CD44 triggered slow rolling through a common, lipid raft-dependent pathway that used the SFKs Hck and Lyn as well as Fgr. We identified the Tec kinase Bruton tyrosine kinase as a key signaling intermediate between Syk and p38. E-selectin engagement of PSGL-1 was dependent on its cytoplasmic domain to activate SFKs and slow rolling. Although recruiting phosphoinositide-3-kinase to the PSGL-1 cytoplasmic domain was reported to activate integrins, E-selectin-mediated slow rolling did not require phosphoinositide-3-kinase. Studies in mice confirmed the physiologic significance of these events for neutrophil slow rolling and recruitment during inflammation. Thus, E-selectin triggers common signals through distinct neutrophil glycoproteins to induce alpha(L)beta(2)-dependent slow rolling.

Ultra-thin grain-oriented silicon steel sheet fabricated by a novel way: Twin-roll strip casting and two-stage cold rolling

NASA Astrophysics Data System (ADS)

Wang, Yin-Ping; Liu, Hai-Tao; Song, Hong-Yu; Liu, Jia-Xin; Shen, Hui-Ying; Jin, Yang; Wang, Guo-Dong

2018-04-01

0.05-0.15 mm-thick ultra-thin grain-oriented silicon steel sheets were successfully produced by a novel processing route including strip casting, hot rolling, normalizing, two-stage cold rolling with intermediate annealing, primary recrystallization annealing and secondary recrystallization annealing. The evolutions of microstructure, texture and inhibitor along the processing were briefly investigated. The results showed that the initial Goss orientation originated due to the heterogenous nucleation of δ-ferrite grains during solidification. Because of the lack of shear deformation, only a few Goss grains were observed in the hot rolled sheet. After the first cold rolling and intermediate annealing, Goss texture was enhanced and distributed in the whole thickness. A small number of Goss grains having a high fraction of high energy boundaries exhibited in the primary recrystallization annealed sheet. A large number of fine and dispersed MnS and AlN and a few co-precipitates MnS and AlN with the size range of 10-70 nm were also observed. Interestingly, a well-developed secondary recrystallization microstructure characterized by 10-60 mm grains and a sharp Goss texture were finally produced in the 0.05-0.15 mm-thick ultra-thin sheets. A magnetic induction B8 of 1.72-1.84 T was obtained. Another new finding was that a few {2 3 0}〈0 0 1〉 and {2 1 0}〈1 2 7〉 grains also can grow up abnormally because of the high fraction of high energy boundaries and the size and number advantage, respectively. These non-Goss grains finally deteriorated the magnetic properties of the ultra-thin sheets. In addition, low surface energies of {hk0} planes may also contribute to the abnormal growth of Goss, {2 3 0}〈0 0 1〉 and {2 1 0}〈1 2 7〉 grains.

Rolling circle amplification-based analysis of Sri Lankan cassava mosaic virus isolates from Tamil Nadu, India, suggests a low level of genetic variability.

PubMed

Kushawaha, Akhilesh Kumar; Rabindran, Ramalingam; Dasgupta, Indranil

2018-03-01

Cassava mosaic disease is a widespread disease of cassava in south Asia and the African continent. In India, CMD is known to be caused by two single-stranded DNA viruses (geminiviruses), Indian cassava mosaic virus (ICMV) and Sri Lankan cassava mosdaic virus (SLCMV). Previously, the diversity of ICMV and SLCMV in India has been studied using PCR, a sequence-dependent method. To have a more in-depth study of the variability of the above viruses and to detect any novel geminiviruses associated with CMD, sequence-independent amplification using rolling circle amplification (RCA)-based methods were used. CMD affected cassava plants were sampled across eighty locations in nine districts of the southern Indian state of Tamil Nadu. Twelve complete sequence of coat protein genes of the resident geminiviruses, comprising 256 amino acid residues were generated from the above samples, which indicated changes at only six positions. RCA followed by RFLP of the 80 samples indicated that most samples (47) contained only SLCMV, followed by 8, which were infected jointly with ICMV and SLCMV. In 11 samples, the pattern did not match the expected patterns from either of the two viruses and hence, were variants. Sequence analysis of an average of 700 nucleotides from 31 RCA-generated fragments of the variants indicated identities of 97-99% with the sequence of a previously reported infectious clone of SLCMV. The evidence suggests low levels of genetic variability in the begomoviruses infecting cassava, mainly in the form of scattered single nucleotide changes.

An enhanced chemiluminescence resonance energy transfer aptasensor based on rolling circle amplification and WS2 nanosheet for Staphylococcus aureus detection.

PubMed

Hao, Liling; Gu, Huajie; Duan, Nuo; Wu, Shijia; Ma, Xiaoyuan; Xia, Yu; Tao, Zui; Wang, Zhouping

2017-03-22

A chemiluminescence resonance energy transfer aptasensor was fabricated for the detection of Staphylococcus aureus (S. aureus) with Co 2+ enhanced N-(aminobutyl)-N-(ethylisoluminol) (ABEI) functional flowerlike gold nanoparticles (Co 2+ /ABEI-AuNFs) as donor and WS 2 nanosheet as acceptor. In the presence of S. aureus, rolling circle amplification (RCA) can be started. Partially complementary sequence of RCA product functional ABEI-AuNFs (cDNA-ABEI-AuNFs) were then annealed to multiple sites of the RCA product to form duplex complex. This complex is less adsorbed onto the WS 2 nanosheet, thus attenuating the quenching of ABEI-AuNFs chemiluminescence by WS 2 nanosheet. In the absence of target S. aureus (and hence the absence of RCA and duplex formation), the free cDNA-ABEI-AuNFs is completely adsorbed onto the WS 2 nanosheet and chemiluminescence quenching ensues. Under optimal conditions, the logarithmic correlation between the concentration of S. aureus and the CL signal was found to be linear within the range of 50 cfu/mL to 1.5 × 10 5  cfu/mL (R 2  = 0.9913). The limits of detection of the developed method were found to be 15 cfu/mL for S. aureus. The selectivity and the capability of the biosensor in meat samples were also studied. Therefore, this simple and easy operation method can be used to detect S. aureus with high sensitivity and specificity. Copyright © 2017 Elsevier B.V. All rights reserved.

Replication of avocado sunblotch viroid: evidence for a symmetric pathway with two rolling circles and hammerhead ribozyme processing.

PubMed Central

Daròs, J A; Marcos, J F; Hernández, C; Flores, R

1994-01-01

The structure of a series of RNAs extracted from avocado infected by the 247-nt avocado sunblotch viroid (ASBVd) was investigated. The identification of multistranded complexes containing circular ASBVd RNAs of (+) and (-) polarity suggests that replication of ASBVd proceeds through a symmetric pathway with two rolling circles where these two circular RNAs are the templates. This is in contrast to the replication of potato spindle tuber viroid and probably of most of its related viroids, which proceeds via an asymmetric pathway where circular (+)-strand and linear multimeric (-)-strand RNAs are the two templates. Linear (+) and (-) ASBVd RNAs of subgenomic length (137 nt and about 148 nt, respectively) and one linear (+)-strand ASBVd RNA of supragenomic length (383-384 nt) were also found in viroid-infected tissue. The two linear (+)-strand RNAs have the same 5'- and 3'-terminal sequences, with the supragenomic species being a fusion product of the monomeric and subgenomic (+)-strand ASBVd RNAs. The 3' termini of these two (+)-strand molecules, which at least in the subgenomic RNA has an extra nontemplate cytidylate residue, could represent sites of either premature termination of the (+)-strands or specific initiation of the (-)-strands. The 5' termini of sub- and supragenomic (+)-strand and the 5' terminus of the subgenomic (-)-strand ASBVd RNA are identical to those produced in the in vitro self-cleavage reactions of (+) and (-) dimeric ASBVd RNAs, respectively. These observations strongly suggest that the hammerhead structures which mediate the in vitro self-cleavage reactions are also operative in vivo. Images Fig. 1 Fig. 3 Fig. 4 Fig. 5 PMID:7809126

A Label-Free and Sensitive Fluorescent Qualitative Assay for Bisphenol A Based on Rolling Circle Amplification/Exonuclease III-Combined Cascade Amplification.

PubMed

Li, Xia; Song, Juan; Xue, Qing-Wang; You, Fu-Heng; Lu, Xia; Kong, Yan-Cong; Ma, Shu-Yi; Jiang, Wei; Li, Chen-Zhong

2016-10-21

Bisphenol A (BPA) detection in drinking water and food packaging materials has attracted much attention since the discovery that BPA can interfere with normal physiological processes and cause adverse health effects. Here, we constructed a label-free aptamer fluorescent assay for selective and sensitive detection of BPA based on the rolling circle amplification (RCA)/Exonuclease III (Exo III)-combined cascade amplification strategy. First, the duplex DNA probe (RP) with anti-BPA aptamer and trigger sequence was designed for BPA recognition and signal amplification. Next, under the action of BPA, the trigger probe was liberated from RP to initiate RCA reaction as primary amplification. Subsequently, the RCA products were used to trigger Exo III assisted secondary amplification with the help of hairpin probes, producing plenty of "G-quadruplex" in lantern-like structures. Finally, the continuously enriched "G-quadruplex lanterns" were lightened by zinc(II)-protoporphyrin IX (ZnPPIX) generating enhanced fluorescence signals. By integrating the primary RCA and secondary Exo III mediated cascade amplification strategy, this method displayed an excellent sensitivity with the detection limits of 5.4 × 10 -17 M. In addition, the anti-BPA aptamer exhibits high recognition ability with BPA, guaranteeing the specificity of detection. The reporter signal probe (G-quadruplex with ZnPPIX) provides a label-free fluorescence signals readout without complicated labeling procedures, making the method simple in design and cost-effective in operation. Moreover, environmental samples analysis was also performed, suggesting that our strategy was reliable and had a great potential application in environmental monitoring.

A Label-Free and Sensitive Fluorescent Qualitative Assay for Bisphenol A Based on Rolling Circle Amplification/Exonuclease III-Combined Cascade Amplification

PubMed Central

Li, Xia; Song, Juan; Xue, Qing-Wang; You, Fu-Heng; Lu, Xia; Kong, Yan-Cong; Ma, Shu-Yi; Jiang, Wei; Li, Chen-Zhong

2016-01-01

Bisphenol A (BPA) detection in drinking water and food packaging materials has attracted much attention since the discovery that BPA can interfere with normal physiological processes and cause adverse health effects. Here, we constructed a label-free aptamer fluorescent assay for selective and sensitive detection of BPA based on the rolling circle amplification (RCA)/Exonuclease III (Exo III)-combined cascade amplification strategy. First, the duplex DNA probe (RP) with anti-BPA aptamer and trigger sequence was designed for BPA recognition and signal amplification. Next, under the action of BPA, the trigger probe was liberated from RP to initiate RCA reaction as primary amplification. Subsequently, the RCA products were used to trigger Exo III assisted secondary amplification with the help of hairpin probes, producing plenty of “G-quadruplex” in lantern-like structures. Finally, the continuously enriched “G-quadruplex lanterns” were lightened by zinc(II)-protoporphyrin IX (ZnPPIX) generating enhanced fluorescence signals. By integrating the primary RCA and secondary Exo III mediated cascade amplification strategy, this method displayed an excellent sensitivity with the detection limits of 5.4 × 10−17 M. In addition, the anti-BPA aptamer exhibits high recognition ability with BPA, guaranteeing the specificity of detection. The reporter signal probe (G-quadruplex with ZnPPIX) provides a label-free fluorescence signals readout without complicated labeling procedures, making the method simple in design and cost-effective in operation. Moreover, environmental samples analysis was also performed, suggesting that our strategy was reliable and had a great potential application in environmental monitoring. PMID:28335318

Novel One-Tube-One-Step Real-Time Methodology for Rapid Transcriptomic Biomarker Detection: Signal Amplification by Ternary Initiation Complexes.

PubMed

Fujita, Hiroto; Kataoka, Yuka; Tobita, Seiji; Kuwahara, Masayasu; Sugimoto, Naoki

2016-07-19

We have developed a novel RNA detection method, termed signal amplification by ternary initiation complexes (SATIC), in which an analyte sample is simply mixed with the relevant reagents and allowed to stand for a short time under isothermal conditions (37 °C). The advantage of the technique is that there is no requirement for (i) heat annealing, (ii) thermal cycling during the reaction, (iii) a reverse transcription step, or (iv) enzymatic or mechanical fragmentation of the target RNA. SATIC involves the formation of a ternary initiation complex between the target RNA, a circular DNA template, and a DNA primer, followed by rolling circle amplification (RCA) to generate multiple copies of G-quadruplex (G4) on a long DNA strand like beads on a string. The G4s can be specifically fluorescence-stained with N(3)-hydroxyethyl thioflavin T (ThT-HE), which emits weakly with single- and double-stranded RNA/DNA but strongly with parallel G4s. An improved dual SATIC system, which involves the formation of two different ternary initiation complexes in the RCA process, exhibited a wide quantitative detection range of 1-5000 pM. Furthermore, this enabled visual observation-based RNA detection, which is more rapid and convenient than conventional isothermal methods, such as reverse transcription-loop-mediated isothermal amplification, signal mediated amplification of RNA technology, and RNA-primed rolling circle amplification. Thus, SATIC methodology may serve as an on-site and real-time measurement technique for transcriptomic biomarkers for various diseases.

A graphene-based biosensing platform based on the release of DNA probes and rolling circle amplification.

PubMed

Liu, Meng; Song, Jinping; Shuang, Shaomin; Dong, Chuan; Brennan, John D; Li, Yingfu

2014-06-24

We report a versatile biosensing platform capable of achieving ultrasensitive detection of both small-molecule and macromolecular targets. The system features three components: reduced graphene oxide for its ability to adsorb single-stranded DNA molecules nonspecifically, DNA aptamers for their ability to bind reduced graphene oxide but undergo target-induced conformational changes that facilitate their release from the reduced graphene oxide surface, and rolling circle amplification (RCA) for its ability to amplify a primer-template recognition event into repetitive sequence units that can be easily detected. The key to the design is the tagging of a short primer to an aptamer sequence, which results in a small DNA probe that allows for both effective probe adsorption onto the reduced graphene oxide surface to mask the primer domain in the absence of the target, as well as efficient probe release in the presence of the target to make the primer available for template binding and RCA. We also made an observation that the circular template, which on its own does not cause a detectable level of probe release from the reduced graphene oxide, augments target-induced probe release. The synergistic release of DNA probes is interpreted to be a contributing factor for the high detection sensitivity. The broad utility of the platform is illustrated though engineering three different sensors that are capable of achieving ultrasensitive detection of a protein target, a DNA sequence and a small-molecule analyte. We envision that the approach described herein will find useful applications in the biological, medical, and environmental fields.

Roll splitting as an alternative intermediate process for wood fuel

Treesearch

Paul E. Barnett; Donald L. Sirois

1985-01-01

In an effort to develop mobile equipment for harvesting and processing woody biomass from power line rights-of-way and precommerial thinnings, numerous alternative concepts were evaluated by Tennessee Valley Authority's Timber Harvesting Project.

New high-strength, high-conductivity Cu-Ag alloy sheets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sakai, Y.; Inoue, K.; Maeda, H.

1995-04-01

A sheet-conductor fabrication method has been developed for Cu-Ag alloys containing 6--24 wt% Ag in which high-strength and high-conductivity are obtained by coldworking combined with intermediate heat treatments. The intermediate heat treatments were repeated three times at 400--450 C for 1--2 h at appropriate stages of cold-rolling. The optimized Cu-24 wt% Ag alloy sheet with a 96% reduction ratio shows an ultimate tensile strength of 1,050 MPa and an electrical conductivity of 75% IACS at room temperature. Anisotropy in the strength with respect to the rolling direction is less than 10%, and no anisotropy in the electrical conductivity occurs. Themore » authors demonstrated the ability to manufacture the Cu-Ag sheets for Bitter magnet on a commercial basis. The sheets fabricated by this method are promising as conductors for high-field Bitter magnet coils.« less

Manufacturing Process Development to Produce Depleted Uranium Wire for EBAM Feedstock

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alexander, David John; Clarke, Kester Diederik; Coughlin, Daniel Robert

2015-06-30

Wire produced from depleted uranium (DU) is needed as feedstock for the Electron-Beam Additive Manufacturing (EBAM) process. The goal is to produce long lengths of DU wire with round or rectangular cross section, nominally 1.5 mm (0.060 inches). It was found that rolling methods, rather than swaging or drawing, are preferable for production of intermediate quantities of DU wire. Trials with grooveless rolling have shown that it is suitable for initial reductions of large stock. Initial trials with grooved rolling have been successful, for certain materials. Modified square grooves (square round-bottom vee grooves) with 12.5 % reduction of area permore » pass have been selected for the reduction process.« less

Navigating in foldonia: Using accelerated molecular dynamics to explore stability, unfolding and self-healing of the β-solenoid structure formed by a silk-like polypeptide

PubMed Central

Zhao, Binwu

2017-01-01

The β roll molecules with sequence (GAGAGAGQ)10 stack via hydrogen bonding to form fibrils which have been themselves been used to make viral capsids of DNA strands, supramolecular nanotapes and pH-responsive gels. Accelerated molecular dynamics (aMD) simulations are used to investigate the unfolding of a stack of two β roll molecules, (GAGAGAGQ)10, to shed light on the folding mechanism by which silk-inspired polypeptides form fibrils and to identify the dominant forces that keep the silk-inspired polypeptide in a β roll configuration. Our study shows that a molecule in a stack of two β roll molecules unfolds in a step-wise fashion mainly from the C terminal. The bottom template is found to play an important role in stabilizing the β roll structure of the molecule on top by strengthening the hydrogen bonds in the layer that it contacts. Vertical hydrogen bonds within the β roll structure are considerably weaker than lateral hydrogen bonds, signifying the importance of lateral hydrogen bonds in stabilizing the β roll structure. Finally, an intermediate structure was found containing a β hairpin and an anti-parallel β sheet consisting of strands from the top and bottom molecules, revealing the self-healing ability of the β roll stack. PMID:28329017

Dew inspired breathing-based detection of genetic point mutation visualized by naked eye

PubMed Central

Xie, Liping; Wang, Tongzhou; Huang, Tianqi; Hou, Wei; Huang, Guoliang; Du, Yanan

2014-01-01

A novel label-free method based on breathing-induced vapor condensation was developed for detection of genetic point mutation. The dew-inspired detection was realized by integration of target-induced DNA ligation with rolling circle amplification (RCA). The vapor condensation induced by breathing transduced the RCA-amplified variances in DNA contents into visible contrast. The image could be recorded by a cell phone for further or even remote analysis. This green assay offers a naked-eye-reading method potentially applied for point-of-care liver cancer diagnosis in resource-limited regions. PMID:25199907

ICTV Virus Taxonomy Profile: Avsunviroidae.

PubMed

Di Serio, Francesco; Li, Shi-Fang; Matoušek, Jaroslav; Owens, Robert A; Pallás, Vicente; Randles, John W; Sano, Teruo; Verhoeven, Jacobus Th J; Vidalakis, Georgios; Flores, Ricardo; Ictv Report Consortium

2018-05-01

Members of the family Avsunviroidae have a single-stranded circular RNA genome that adopts a rod-like or branched conformation and can form, in the strands of either polarity, hammerhead ribozymes involved in their replication in plastids through a symmetrical RNA-RNA rolling-circle mechanism. These viroids lack the central conserved region typical of members of the family Pospiviroidae. The family Avsunviroidae includes three genera, Avsunviroid, Pelamoviroid and Elaviroid, with a total of four species. This is a summary of the ICTV Report on the taxonomy of the family Avsunviroidae, which is available at http://www.ictv.global/report/avsunviroidae.

Dew inspired breathing-based detection of genetic point mutation visualized by naked eye

NASA Astrophysics Data System (ADS)

Xie, Liping; Wang, Tongzhou; Huang, Tianqi; Hou, Wei; Huang, Guoliang; Du, Yanan

2014-09-01

A novel label-free method based on breathing-induced vapor condensation was developed for detection of genetic point mutation. The dew-inspired detection was realized by integration of target-induced DNA ligation with rolling circle amplification (RCA). The vapor condensation induced by breathing transduced the RCA-amplified variances in DNA contents into visible contrast. The image could be recorded by a cell phone for further or even remote analysis. This green assay offers a naked-eye-reading method potentially applied for point-of-care liver cancer diagnosis in resource-limited regions.

Dew inspired breathing-based detection of genetic point mutation visualized by naked eye.

PubMed

Xie, Liping; Wang, Tongzhou; Huang, Tianqi; Hou, Wei; Huang, Guoliang; Du, Yanan

2014-09-09

A novel label-free method based on breathing-induced vapor condensation was developed for detection of genetic point mutation. The dew-inspired detection was realized by integration of target-induced DNA ligation with rolling circle amplification (RCA). The vapor condensation induced by breathing transduced the RCA-amplified variances in DNA contents into visible contrast. The image could be recorded by a cell phone for further or even remote analysis. This green assay offers a naked-eye-reading method potentially applied for point-of-care liver cancer diagnosis in resource-limited regions.

Dynamic Measurement for the Diameter of A Train Wheel Based on Structured-Light Vision

PubMed Central

Gong, Zheng; Sun, Junhua; Zhang, Guangjun

2016-01-01

Wheels are very important for the safety of a train. The diameter of the wheel is a significant parameter that needs regular inspection. Traditional methods only use the contact points of the wheel tread to fit the rolling round. However, the wheel tread is easily influenced by peeling or scraping. Meanwhile, the circle fitting algorithm is sensitive to noise when only three points are used. This paper proposes a dynamic measurement method based on structured-light vision. The axle of the wheelset and the tread are both employed. The center of the rolling round is determined by the axle rather than the tread only. Then, the diameter is calculated using the center and the contact points together. Simulations are performed to help design the layout of the sensors, and the influences of different noise sources are also analyzed. Static and field experiments are both performed, and the results show it to be quite stable and accurate. PMID:27104543

KSC-99pp0539

NASA Image and Video Library

1999-05-16

KENNEDY SPACE CENTER, FLA. -- Inside High Bay 1 of the Vehicle Assembly Building (VAB) Mike Sestile, with United Space Alliance, draws circles around divots in the foam insulation on the top of the external tank of Space Shuttle Discovery. About 150 divots were caused by hail during recent storms. The Shuttle was rolled back from Pad 39B to the VAB for repairs because access to all of the damaged areas was not possible at the pad. The work is expected to take two to three days, allowing Discovery to roll back to the pad as early as May 20 for launch of mission STS-96, the 94th launch in the Space Shuttle Program. Liftoff will occur no earlier than May 27. STS-96 is a logistics and resupply mission for the International Space Station, carrying such payloads as a Russian crane, the Strela; a U.S.-built crane; the Spacehab Oceaneering Space System Box (SHOSS), a logistics items carrier; and STARSHINE, a student-shared experiment

Dynamic Measurement for the Diameter of A Train Wheel Based on Structured-Light Vision.

PubMed

Gong, Zheng; Sun, Junhua; Zhang, Guangjun

2016-04-20

Wheels are very important for the safety of a train. The diameter of the wheel is a significant parameter that needs regular inspection. Traditional methods only use the contact points of the wheel tread to fit the rolling round. However, the wheel tread is easily influenced by peeling or scraping. Meanwhile, the circle fitting algorithm is sensitive to noise when only three points are used. This paper proposes a dynamic measurement method based on structured-light vision. The axle of the wheelset and the tread are both employed. The center of the rolling round is determined by the axle rather than the tread only. Then, the diameter is calculated using the center and the contact points together. Simulations are performed to help design the layout of the sensors, and the influences of different noise sources are also analyzed. Static and field experiments are both performed, and the results show it to be quite stable and accurate.

Photosystem II functionality and antioxidant system changes during leaf rolling in post-stress emerging Ctenanthe setosa exposed to drought.

PubMed

Terzi, Rabiye; Saruhan, Neslihan; Sağlam, A; Nar, Hatice; Kadioğlu, A

2009-12-01

We studied the changes in antioxidant system and chlorophyll fluorescence parameters in post-stress emerging Ctenanthe setosa (Rosc.) Eichler (Marantaceae) plants (PSE plants) having reduced leaf area under drought stress causing leaf rolling and re-watering. PSE plants were compared to primary stressed plants (PS) in previous studies. The parameters were measured at different visual leaf rolling scores from 1 to 4 (1 is unrolled, 4 is tightly rolled and the others is intermediate form). Water potentials and stomatal conductance of leaves were gradually decreased during leaf rolling. Similarly, maximum quantum efficiency of open PS II center and quantum yield of PS II decreased during the rolling period. Non-photochemical quenching of chlorophyll fluorescence decreased at score 2 then increased while photochemical quenching did not change during leaf rolling. Electron transport rate decreased only at score 4 but approximately reached to score 1 level after re-watering. Superoxide dismutase activity was not constant at all leaf rolling scores. Ascorbate peroxidase, catalase and glutathione reductase activities generally tended to increase during leaf rolling. Lipid peroxidation and H 2 O 2 content increased at score 2 but decreased at the later scores. On the other hand, O 2 .- production increased during the rolling period. After re-watering of the plants having score 4 of leaf rolling, antioxidant enzyme activities were lower than those of score 1. Other physiological parameters also tended to reach the value of score 1. The results indicated that PSE plants gained drought tolerance by reducing leaf area effectively induced their antioxidant systems and protected the photosynthesis under drought stress similar to PS plants.

40 CFR 1066.210 - Dynamometers.

Code of Federal Regulations, 2012 CFR

2012-07-01

... chassis dynamometer typically uses electrically generated load forces combined with its rotational inertia... (known as “road load”). Load forces are calculated using vehicle-specific coefficients and response characteristics. The load forces are applied to the vehicle tires by rolls connected to intermediate motor...

40 CFR 1066.210 - Dynamometers.

Code of Federal Regulations, 2013 CFR

2013-07-01

... chassis dynamometer typically uses electrically generated load forces combined with its rotational inertia... (known as “road load”). Load forces are calculated using vehicle-specific coefficients and response characteristics. The load forces are applied to the vehicle tires by rolls connected to intermediate motor...

A family of selfish minicircular chromosomes with jumbled chloroplast gene fragments from a dinoflagellate.

PubMed

Zhang, Z; Cavalier-Smith, T; Green, B R

2001-08-01

Chloroplast genes of several dinoflagellate species are located on unigenic DNA minicircular chromosomes. We have now completely sequenced five aberrant minicircular chromosomes from the dinoflagellate Heterocapsa triquetra. These probably nonfunctional DNA circles lack complete genes, with each being composed of several short fragments of two or three different chloroplast genes and a common conserved region with a tripartite 9G-9A-9G core like the putative replicon origin of functional single-gene circular chloroplast chromosomes. Their sequences imply that all five circles evolved by differential deletions and duplications from common ancestral circles bearing fragments of four genes: psbA, psbC, 16S rRNA, and 23S rRNA. It appears that recombination between separate unigenic chromosomes initially gave intermediate heterodimers, which were subsequently stabilized by deletions that included part or all of one putative replicon origin. We suggest that homologous recombination at the 9G-9A-9G core regions produced a psbA/psbC heterodimer which generated two distinct chimeric circles by differential deletions and duplications. A 23S/16S rRNA heterodimer more likely formed by illegitimate recombination between 16S and 23S rRNA genes. Homologous recombination between the 9G-9A-9G core regions of both heterodimers and additional differential deletions and duplications could then have yielded the other three circles. Near identity of the gene fragments and 9G-9A-9G cores, despite diverging adjacent regions, may be maintained by gene conversion. The conserved organization of the 9G-9A-9G cores alone favors the idea that they are replicon origins and suggests that they may enable the aberrant minicircles to parasitize the chloroplast's replication machinery as selfish circles.

Test--retest variability of Randot stereoacuity measures gathered in an unselected sample of UK primary school children.

PubMed

Adler, Paul; Scally, Andrew J; Barrett, Brendan T

2012-05-01

To determine the test-retest reliability of the Randot stereoacuity test when used as part of vision screening in schools. Randot stereoacuity (graded-circles) and logMAR visual acuity measures were gathered in an unselected sample of 139 children (aged 4-12, mean 8.1±2.1 years) in two schools. Randot testing was repeated on two occasions (average interval between successive tests 8 days, range: 1-21 days). Three Randot scores were obtained in 97.8% of children. Randot stereoacuity improved by an average of one plate (ie, one test level) on repeat testing but was little changed when tested on the third occasion. Within-subject variability was up to three test levels on repeat testing. When stereoacuity was categorised as 'fine', 'intermediate' or 'coarse', the greatest variability was found among younger children who exhibited 'intermediate' or 'coarse'/nil stereopsis on initial testing. Whereas 90.8% of children with 'fine' stereopsis (≤50 arc-seconds) on the first test exhibited 'fine' stereopsis on both subsequent tests, only ∼16% of children with 'intermediate' (>50 but ≤140 arc-seconds) or 'coarse'/nil (≥200 arc-seconds) stereoacuity on initial testing exhibited stable test results on repeat testing. Children exhibiting abnormal stereoacuity on initial testing are very likely to exhibit a normal result when retested. The value of a single, abnormal Randot graded-circles stereoacuity measure from school screening is therefore questionable.

Visualization and Enumeration of Bacteria Carrying a Specific Gene Sequence by In Situ Rolling Circle Amplification

PubMed Central

Maruyama, Fumito; Kenzaka, Takehiko; Yamaguchi, Nobuyasu; Tani, Katsuji; Nasu, Masao

2005-01-01

Rolling circle amplification (RCA) generates large single-stranded and tandem repeats of target DNA as amplicons. This technique was applied to in situ nucleic acid amplification (in situ RCA) to visualize and count single Escherichia coli cells carrying a specific gene sequence. The method features (i) one short target sequence (35 to 39 bp) that allows specific detection; (ii) maintaining constant fluorescent intensity of positive cells permeabilized extensively after amplicon detection by fluorescence in situ hybridization, which facilitates the detection of target bacteria in various physiological states; and (iii) reliable enumeration of target bacteria by concentration on a gelatin-coated membrane filter. To test our approach, the presence of the following genes were visualized by in situ RCA: green fluorescent protein gene, the ampicillin resistance gene and the replication origin region on multicopy pUC19 plasmid, as well as the single-copy Shiga-like toxin gene on chromosomes inside E. coli cells. Fluorescent antibody staining after in situ RCA also simultaneously identified cells harboring target genes and determined the specificity of in situ RCA. E. coli cells in a nonculturable state from a prolonged incubation were periodically sampled and used for plasmid uptake study. The numbers of cells taking up plasmids determined by in situ RCA was up to 106-fold higher than that measured by selective plating. In addition, in situ RCA allowed the detection of cells taking up plasmids even when colony-forming cells were not detected during the incubation period. By optimizing the cell permeabilization condition for in situ RCA, this method can become a valuable tool for studying free DNA uptake, especially in nonculturable bacteria. PMID:16332770

Massive amplification of rolling-circle transposons in the lineage of the bat Myotis lucifugus

PubMed Central

Pritham, Ellen J.; Feschotte, Cédric

2007-01-01

Rolling-circle (RC) transposons, or Helitrons, are a newly recognized group of eukaryotic transposable elements abundant in the genomes of plants, invertebrates, and zebrafish. We provide evidence for the colonization of a mammalian genome by Helitrons, which has not been reported previously. We identified and characterized two families of Helitrons in the little brown bat Myotis lucifugus. The consensus sequence for the first family, HeliBat1, displays the hallmarks of an autonomous Helitron, including coding capacity for an ≈1,500-aa protein with an RC replication motif and a region related to the SF1 superfamily of DNA helicases. The HeliBatN1 family is a nonautonomous Helitron family that is only distantly related to HeliBat1. The two HeliBat families have attained high copy numbers (≈15,000 and > 100,000 copies, respectively) and make up at least ≈3% of the M. lucifugus genome. Sequence divergence and cross-species analyses indicate that both HeliBat families have amplified within the last ≈30–36 million years and are restricted to the lineage of vesper bats. We could not detect the presence of Helitrons in any other order of placental mammals, despite the broad representation of these taxa in the databases. We describe an instance of HeliBat-mediated transduction of a host gene fragment that was subsequently dispersed in ≈1,000 copies throughout the M. lucifugus genome. Given the demonstrated propensity of RC transposons to mediate the duplication and shuffling of host genes in bacteria and maize, it is tempting to speculate that the massive amplification of Helitrons in vesper bats has influenced the evolutionary trajectory of these mammals. PMID:17261799

CdTe/CdSe quantum dot-based fluorescent aptasensor with hemin/G-quadruplex DNzyme for sensitive detection of lysozyme using rolling circle amplification and strand hybridization.

PubMed

Qiu, Zhenli; Shu, Jian; He, Yu; Lin, Zhenzhen; Zhang, Kangyao; Lv, Shuzhen; Tang, Dianping

2017-01-15

Lysozyme with a small monomeric globular enzymatic protein is part of the innate immune system, and its deficiency can cause the increased incidence of disease. Herein, we devise a new signal-enhanced fluorescence aptasensing platform for quantitative screening of lysozyme by coupling with rolling circle amplification (RCA) and strand hybridization reaction, accompanying the assembly of CdTe/CdSe quantum dots (QDs) and hemin/G-quadruplex DNzyme. Initially, target-triggered release of the primer was carried out from DNA duplex via the reaction of the aptamer with the analyte, and the released primer could be then utilized as the template to produce numerous repeated oligonucleotide sequences by the RCA reaction. Following that, the formed long-stranded DNA simultaneously hybridized with the CdTe/CdSe QD-labeled probe and hemin/G-quadruplex DNzyme strand in the system, thereby resulting in the quenching of QD fluorescent signal through the proximity hemin/G-quadruplex DNzyme on the basis of transferring photoexcited conduction band electrons of quantum dots to Fe(III)/Fe(II)-protoporphyrin IX (hemin) complex. Under optimal conditions, the fluorescent signal decreased with the increasing target lysozyme within the dynamic range from 5.0 to 500nM with a detection limit (LOD) of 2.6nM at the 3s blank criterion. Intra-assay and interassay coefficients of variation (CVs) were below 8.5% and 11.5%, respectively. Finally, the system was applied to analyze spiked human serum samples, and the recoveries in all cases were 85-111.9%. Copyright © 2016 Elsevier B.V. All rights reserved.

Mobilization Function of the pBHR1 Plasmid, a Derivative of the Broad-Host-Range Plasmid pBBR1

PubMed Central

Szpirer, Cédric Y.; Faelen, Michel; Couturier, Martine

2001-01-01

The pBHR1 plasmid is a derivative of the small (2.6-kb), mobilizable broad-host-range plasmid pBBR1, which was isolated from the gram-negative bacterium Bordetella bronchiseptica (R. Antoine and C. Locht, Mol. Microbiol. 6:1785–1799, 1992). Plasmid pBBR1 consists of two functional cassettes and presents sequence similarities with the transfer origins of several plasmids and mobilizable transposons from gram-positive bacteria. We show that the Mob protein specifically recognizes a 52-bp sequence which contains, in addition to the transfer origin, the promoter of the mob gene. We demonstrate that this gene is autoregulated. The binding of the Mob protein to the 52-bp sequence could thus allow the formation of a protein-DNA complex with a double function: relaxosome formation and mob gene regulation. We show that the Mob protein is a relaxase, and we located the nic site position in vitro. After sequence alignment, the position of the nic site of pBBR1 corresponds with those of the nick sites of the Bacteroides mobilizable transposon Tn4555 and the streptococcal plasmid pMV158. The oriT of the latter is characteristic of a family of mobilizable plasmids that are found in gram-positive bacteria and that replicate by the rolling-circle mechanism. Plasmid pBBR1 thus appears to be a new member of this group, even though it resides in gram-negative bacteria and does not replicate via a rolling-circle mechanism. In addition, we identified two amino acids of the Mob protein necessary for its activity, and we discuss their involvement in the mobilization mechanism. PMID:11222611

A cascade amplification strategy based on rolling circle amplification and hydroxylamine amplified gold nanoparticles enables chemiluminescence detection of adenosine triphosphate.

PubMed

Wang, Ping; Zhang, Tonghuan; Yang, Taoyi; Jin, Nan; Zhao, Yanjun; Fan, Aiping

2014-08-07

A highly sensitive and selective chemiluminescent (CL) biosensor for adenosine triphosphate (ATP) was developed by taking advantage of the ATP-dependent enzymatic reaction (ATP-DER), the powerful signal amplification capability of rolling circle amplification (RCA), and hydroxylamine-amplified gold nanoparticles (Au NPs). The strategy relies on the ability of ATP, a cofactor of T4 DNA ligase, to trigger the ligation-RCA reaction. In the presence of ATP, the T4 DNA ligase catalyzes the ligation reaction between the two ends of the padlock probe, producing a closed circular DNA template that initiates the RCA reaction with phi29 DNA polymerase and dNTP. Therein, many complementary copies of the circular template can be generated. The ATP-DER is eventually converted into a detectable CL signal after a series of processes, including gold probe hybridization, hydroxylamine amplification, and oxidative gold metal dissolution coupled with a simple and sensitive luminol CL reaction. The CL signal is directly proportional to the ATP level. The results showed that the detection limit of the assay is 100 pM of ATP, which compares favorably with those of other ATP detection techniques. In addition, by taking advantage of ATP-DER, the proposed CL sensing system exhibits extraordinary specificity towards ATP and could distinguish the target molecule ATP from its analogues. The proposed method provides a new and versatile platform for the design of novel DNA ligation reaction-based CL sensing systems for other cofactors. This novel ATP-DER based CL sensing system may find wide applications in clinical diagnosis as well as in environmental and biomedical fields.

Ligation-rolling circle amplification combined with γ-cyclodextrin mediated stemless molecular beacon for sensitive and specific genotyping of single-nucleotide polymorphism.

PubMed

Zou, Zhen; Qing, Zhihe; He, Xiaoxiao; Wang, Kemin; He, Dinggeng; Shi, Hui; Yang, Xue; Qing, Taiping; Yang, Xiaoxiao

2014-07-01

A novel approach for highly sensitive and selective genotyping of single-nucleotide polymorphism (SNP) has been developed based on ligation-rolling circle amplification (L-RCA) and stemless molecular beacon. In this approach, two tailored DNA probes were involved. The stemless molecular beacon, formed through the inclusion interactions of γ-cyclodextrin (γ-CD) and bis-pyrene labeled DNA fragment, was served as signal probe. In the absence of mutant target, the two pyrene molecules were bound in the γ-CD cavity to form an excimer and showed a strong fluorescence at 475 nm. It was here named γ-CD-P-MB. The padlock DNA probe was designed as recognition probe. Upon the recognition of a point mutation DNA targets, the padlock probe was ligated to generate a circular template. An RCA amplification was then initiated using the circular template in the presence of Phi29 polymerase and dNTPs. The L-RCA products, containing repetitive sequence units, subsequently hybridized with the γ-CD-P-MB. This made pyrene molecules away from γ-CD cavity and caused a decrease of excimer fluorescence. As a proof-of-concept, SNP typing of β-thalassemia gene at position -28 was investigated using this approach. The detection limit of mutated target was determined to be 40 fM. In addition, DNA ligase offered high fidelity in distinguishing the mismatched bases at the ligation site, resulting in positive detection of mutant target even when the ratio of the wildtype to the mutant is 999:1. Given these attractive characteristics, the developed approach might provide a great genotyping platform for pathogenic diagnosis and genetic analysis. Copyright © 2014 Elsevier B.V. All rights reserved.

High-mobility group 1/2 proteins are essential for initiating rolling-circle-type DNA replication at a parvovirus hairpin origin.

PubMed

Cotmore, S F; Tattersall, P

1998-11-01

Rolling-circle replication is initiated by a replicon-encoded endonuclease which introduces a single-strand nick into specific origin sequences, becoming covalently attached to the 5' end of the DNA at the nick and providing a 3' hydroxyl to prime unidirectional, leading-strand synthesis. Parvoviruses, such as minute virus of mice (MVM), have adapted this mechanism to amplify their linear single-stranded genomes by using hairpin telomeres which sequentially unfold and refold to shuttle the replication fork back and forth along the genome, creating a continuous, multimeric DNA strand. The viral initiator protein, NS1, then excises individual genomes from this continuum by nicking and reinitiating synthesis at specific origins present within the hairpin sequences. Using in vitro assays to study ATP-dependent initiation within the right-hand (5') MVM hairpin, we have characterized a HeLa cell factor which is absolutely required to allow NS1 to nick this origin. Unlike parvovirus initiation factor (PIF), the cellular complex which activates NS1 endonuclease activity at the left-hand (3') viral origin, the host factor which activates the right-hand hairpin elutes from phosphocellulose in high salt, has a molecular mass of around 25 kDa, and appears to bind preferentially to structured DNA, suggesting that it might be a member of the high-mobility group 1/2 (HMG1/2) protein family. This prediction was confirmed by showing that purified calf thymus HMG1 and recombinant human HMG1 or murine HMG2 could each substitute for the HeLa factor, activating the NS1 endonuclease in an origin-specific nicking reaction.

Gravity dependence of subjective visual vertical variability.

PubMed

Tarnutzer, A A; Bockisch, C; Straumann, D; Olasagasti, I

2009-09-01

The brain integrates sensory input from the otolith organs, the semicircular canals, and the somatosensory and visual systems to determine self-orientation relative to gravity. Only the otoliths directly sense the gravito-inertial force vector and therefore provide the major input for perceiving static head-roll relative to gravity, as measured by the subjective visual vertical (SVV). Intraindividual SVV variability increases with head roll, which suggests that the effectiveness of the otolith signal is roll-angle dependent. We asked whether SVV variability reflects the spatial distribution of the otolithic sensors and the otolith-derived acceleration estimate. Subjects were placed in different roll orientations (0-360 degrees, 15 degrees steps) and asked to align an arrow with perceived vertical. Variability was minimal in upright, increased with head-roll peaking around 120-135 degrees, and decreased to intermediate values at 180 degrees. Otolith-dependent variability was modeled by taking into consideration the nonuniform distribution of the otolith afferents and their nonlinear firing rate. The otolith-derived estimate was combined with an internal bias shifting the estimated gravity-vector toward the body-longitudinal. Assuming an efficient otolith estimator at all roll angles, peak variability of the model matched our data; however, modeled variability in upside-down and upright positions was very similar, which is at odds with our findings. By decreasing the effectiveness of the otolith estimator with increasing roll, simulated variability matched our experimental findings better. We suggest that modulations of SVV precision in the roll plane are related to the properties of the otolith sensors and to central computational mechanisms that are not optimally tuned for roll-angles distant from upright.

Tachyon warm-intermediate inflationary universe model in high dissipative regime

DOE Office of Scientific and Technical Information (OSTI.GOV)

Setare, M.R.; Kamali, V., E-mail: rezakord@ipm.ir, E-mail: vkamali1362@gmail.com

2012-08-01

We consider tachyonic warm-inflationary models in the context of intermediate inflation. We derive the characteristics of this model in slow-roll approximation and develop our model in two cases, 1- For a constant dissipative parameter Γ. 2- Γ as a function of tachyon field φ. We also describe scalar and tensor perturbations for this scenario. The parameters appearing in our model are constrained by recent observational data. We find that the level of non-Gaussianity for this model is comparable with non-tachyonic model.

Research and Development of Heavy Gauge X80 Pipeline Plate Utilizing Optimized Rolling and Cooling Process

NASA Astrophysics Data System (ADS)

Li, Shaopo; Li, Jiading; Ding, Wenhua; Zhang, Hai

This paper reports on the experience with the production of 27/33 mm X80 heavy wall thicknesses, large OD (48") in Shouqin Steel Co., Ltd. (SQS). Considering the technology capability of the plate mill in SQS, a optimized rolling and cooling process was developed to achieve stable heavy gauge X80 mechanical properties. The importance of the slab reheating process and rolling schedule will be discussed in the paper. In addition, the per pass reductions logic used during recrystallized rough rolling, and special emphasis on the reduction of the final roughing pass prior to the intermediate holding resulting in a fine uniform prior austenite microstructure will be discussed. The optimized cooling process application after finish rolling guarantees the steady control of the final bainitic microstructure with optimum M/A phase for heavy gauge X80 plates. The plates produced by this process achieved good flatness and excellent mechanical properties. SQS has produced 10000 tons 27mm X80 for the Middle Asia C Line Project and 1000 tons 33mm X80 for the 3rd West-to-East Natural Gas Transmission Pipeline Project in 2013-2014. The products utilizing optimized rolling and cooling process showed extremely excellent low temperature toughness.

Structural transformations in hull material clad by nitrogen stainless steel using various methods

NASA Astrophysics Data System (ADS)

Sagaradze, V. V.; Kataeva, N. V.; Mushnikova, S. Yu.; Khar'kov, O. A.; Kalinin, G. Yu.; Yampol'skii, V. D.

2014-02-01

Specimens of a 10N3KhDMBF shipbuilding hull steel were clad by a 04Kh20N6G11M2AFB nitrogen austenitic steel using various treatment conditions, which included hot rolling, austenitic facing, and explosive welding followed by hot rolling and heat treatment. Between the base and cladding materials, an intermediate layer with variable concentrations of chromium, manganese, and nickel was found, in which a martensitic structure was formed. In all the cases, the strength of bonding of the cladding layer to the hull steel (determined in tests for shear to fracture) was fairly high (σsh = 437-520 MPa). The only exception was the specimen produced by unidirectional facing without subsequent hot rolling (σsh = 308 MPa), in which nonfusions between the faced beads of stainless steel were detected.

Self-assembly of free-standing RNA membranes

NASA Astrophysics Data System (ADS)

Han, Daehoon; Park, Yongkuk; Kim, Hyejin; Lee, Jong Bum

2014-07-01

RNA has emerged as a promising material for nanostructure and microstructure engineering. Although rare, some macroscopic RNA structures have also been constructed using lipid or polymer materials. Here, we report the first example of an enzymatically generated RNA membrane. This robust and free-standing RNA membrane has a macroscopic structure and is generated without any polymer support or complexation. Our RNA membrane is fabricated following two sequential processes, complementary rolling circle transcription and evaporation-induced self-assembly, and its structural and functional properties are rationally controlled by adjusting RNA base pairing. In this study, three types of RNA membranes are fabricated and are used to demonstrate potential applications.

Machine protection system for rotating equipment and method

DOEpatents

Lakshminarasimha, Arkalgud N.; Rucigay, Richard J.; Ozgur, Dincer

2003-01-01

A machine protection system and method for rotating equipment introduces new alarming features and makes use of full proximity probe sensor information, including amplitude and phase. Baseline vibration amplitude and phase data is estimated and tracked according to operating modes of the rotating equipment. Baseline vibration and phase data can be determined using a rolling average and variance and stored in a unit circle or tracked using short term average and long term average baselines. The sensed vibration amplitude and phase is compared with the baseline vibration amplitude and phase data. Operation of the rotating equipment can be controlled based on the vibration amplitude and phase.

Chemical Equilibrium and Polynomial Equations: Beware of Roots.

ERIC Educational Resources Information Center

Smith, William R.; Missen, Ronald W.

1989-01-01

Describes two easily applied mathematical theorems, Budan's rule and Rolle's theorem, that in addition to Descartes's rule of signs and intermediate-value theorem, are useful in chemical equilibrium. Provides examples that illustrate the use of all four theorems. Discusses limitations of the polynomial equation representation of chemical…

76 FR 64283 - Airworthiness Directives; Rolls-Royce plc (RR) Turbofan Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-18

... currently requires inspecting the intermediate-pressure (IP) compressor rotor shaft rear balance land for...-Trent 800 IP compressor rotor shafts that have been found cracked. This proposed AD would continue to... identified above could lead to IP compressor rotor shaft failure, uncontained engine failure, and damage to...

78 FR 54149 - Airworthiness Directives; Rolls-Royce plc (RR) Turbofan Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-03

...-10-12 required inspecting the intermediate-pressure (IP) compressor rotor shaft rear balance land for... Trent 500 IP compressor rotor shaft rear balance land during a shop visit. Further engineering... AD to detect cracking on the IP compressor rotor shaft rear balance land, which could lead to...

77 FR 31176 - Airworthiness Directives; Rolls-Royce plc (RR) Turbofan Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-25

... currently requires inspecting the intermediate-pressure (IP) compressor rotor shaft rear balance land for... detect cracking on the IP compressor rotor rear balance land. IP compressor rotor rear balance land...), without sub-headings. Request To Delete the Re-Balance Requirement American Airlines requested that in the...

Rolling chain amplification based signal-enhanced electrochemical aptasensor for ultrasensitive detection of ochratoxin A.

PubMed

Huang, Lin; Wu, Jingjing; Zheng, Lei; Qian, Haisheng; Xue, Feng; Wu, Yucheng; Pan, Daodong; Adeloju, Samuel B; Chen, Wei

2013-11-19

A novel electrochemical aptasensor is described for rapid and ultrasensitive detection of ochratoxin A (OTA) based on signal enhancement with rolling circle amplification (RCA). The primer for RCA was designed to compose of a two-part sequence, one part of the aptamer sequence directed against OTA while the other part was complementary to the capture probe on the electrode surface. In the presence of target OTA, the primer, originally hybridized with the RCA padlock, is replaced to combine with OTA. This induces the inhibition of RCA and decreases the OTA sensing signal obtained with the electrochemical aptasensor. Under the optimized conditions, ultrasensitive detection of OTA was achieved with a limit of detection (LOD) of 0.065 ppt (pg/mL), which is much lower than previously reported. The electrochemical aptasensor was also successfully applied to the determination of OTA in wine samples. This ultrasensitive electrochemical aptasensor is of great practical importance in food safety and could be widely extended to the detection of other toxins by replacing the sequence of the recognition aptamer.

Properties of hot-rolled sheets from ferritic steel with increased strength

NASA Astrophysics Data System (ADS)

Perlovich, Yu.; Isaenkova, M.; Dobrokhotov, P.; Stolbov, S.; Bannykh, O.; Bannykh, I.; Antsyferova, M.

2017-10-01

Sheets from ferritic steel 3 mm thick with increased strength after thermal hardening were studied by use of various X-ray methods and mechanical testing. Rolling of steel was carried out at 1100°C with rather great reductions per pass, so that plastic deformation of metal spread by the significant distance from the surface. The texture of sheet proved to have two sharply different layers: the inner layer of ˜40% thick with the usual rolling texture of BCC metals and the external layer with the rolling texture of FCC metals. At that, within the intermediate layer the texture is weakened. Texture formation within the external layer is conditioned by the process of dynamical deformation ageing: interstitial impurities from atmosphere block dislocations, prevent from their slip and at increased temperatures promote their collective climb. As a result, the direction of lattice rotation as well as the final rolling texture change. Due to texture layering, by impact testing of the sheet the plane of crack propagation must be changed when this crack reaches the inner layer, and then an additional energy for its further movement is required. Thermal hardening of the sheet retains the type of rolling texture, though results in some its scattering, but at the same time the breaking point of steel grows twice owing to formation of intermetallic particles.

Testing an earthquake prediction algorithm

USGS Publications Warehouse

Kossobokov, V.G.; Healy, J.H.; Dewey, J.W.

1997-01-01

A test to evaluate earthquake prediction algorithms is being applied to a Russian algorithm known as M8. The M8 algorithm makes intermediate term predictions for earthquakes to occur in a large circle, based on integral counts of transient seismicity in the circle. In a retroactive prediction for the period January 1, 1985 to July 1, 1991 the algorithm as configured for the forward test would have predicted eight of ten strong earthquakes in the test area. A null hypothesis, based on random assignment of predictions, predicts eight earthquakes in 2.87% of the trials. The forward test began July 1, 1991 and will run through December 31, 1997. As of July 1, 1995, the algorithm had forward predicted five out of nine earthquakes in the test area, which success ratio would have been achieved in 53% of random trials with the null hypothesis.

Head movements in low and high gravitoinertial force environments elicit motion sickness - Implications for space motion sickness

NASA Technical Reports Server (NTRS)

Lackner, James R.; Graybiel, Ashton

1987-01-01

Astronauts report that head movements in flight tend to bring on symptoms of space motion sickness (SMS). The effects of head movements in pitch, yaw, and roll (made both with normal vision and with eyes occluded) on susceptibility to motion sickness in the zero G phase of parabolic flight maneuvers were evaluated. The findings are clear-cut: pitch head movements are most provocative, yaw least provocative, and roll intermediate. These experiments suggest that SMS is not a unique nosological entity, but is the consequence of exposure to nonterrestrial force levels. Head movements during departures in either direction from 1 G elicit symptoms.

Microstructure and Texture Development during Cold Rolling in UNS S32205 and UNS S32760 Duplex Stainless Steels

NASA Astrophysics Data System (ADS)

Kumar, Amit; Khatirkar, Rajesh Kisni; Chalapathi, Darshan; Kumar, Gulshan; Suwas, Satyam

2017-05-01

In the present study, microstructure and texture evolution during cold rolling in UNS S32205 and UNS S32760 duplex stainless steel was investigated. Both steels were unidirectionally cold rolled up to 80 pct thickness reduction. Scanning electron microscopy and electron backscattered diffraction (EBSD) were used for microstructural characterization, while X-ray diffraction (XRD) was used for the measurement of bulk texture. Strain-induced martensite (SIM) was identified and quantified with the help of magnetic measurements (B-H curve and magnetization saturation). With the increase in plastic strain, the grains became morphologically elongated along the rolling direction with the reduction in average band thickness and band spacing. SIM increased with the increase in deformation and was found to be a function of strain and the SFE of austenite. The increase in SIM was much more pronounced in UNS S32205 steel as compared to UNS S32760 steel. After cold rolling, strong α-fiber (RD//<110>) texture was developed in ferrite, while brass texture was dominant in austenite for both steels. The strength of texture components and fibers was stronger in UNS S32760 steel. Another significant feature was the development of weak γ-fiber (ND//<111>) in UNS S32760 steel at intermediate deformation.

Scavenging of reactive oxygen species in apoplastic and symplastic areas of rolled leaves in Ctenanthe setosa under drought stress.

PubMed

Saruhan, Neslihan; Terzi, Rabiye; Sağlam, Aykut; Kadioğlu, Asim

2010-09-01

The correspondence among apoplastic and symplastic antioxidant status, stomatal conductance and water potential was investigated during leaf rolling in Ctenanthe setosa (Rosc.) Eichler (Marantaceae) under drought stress. Apoplastic and symplastic extractions of leaf and petiole were performed at different visual leaf rolling scores from 1 to 4 (1 is unrolled, 4 is tightly rolled and the others are intermediate form). In the leaf symplast, the highest changes were found in catalase (CAT) and guaiacol peroxidase (GPX) activities when compared to score 1 during leaf rolling. No significant change was observed in superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities in the symplast of leaf during the rolling. The same phenomenon was also present in the symplast of petiole except APX activity. In the leaf apoplast, the highest increase occurred in APX and GPX activities, whilst a slight increase in CAT and SOD activities. In the apoplast of petiole, the highest increment was found only in GPX activity, while there were small increases in SOD, APX and CAT activities. Hydrogen peroxide content increased up to score 3 in the apoplast and symplast of leaf and petiole but then slightly decreased. Also, superoxide production increased in the leaf and petiole apoplast but its quantity in the apoplast was much more than that of the symplast. On the other hand, NAD(P)H oxidase activity increased in the leaf but no change was observed in the petiole. In conclusion, as a result of water deficit during leaf rolling antioxidant enzymes are induced to scavenging of ROS produced in symplast and apoplast.

Quantitative Single-Cell mRNA Analysis in Hydrogel Beads.

PubMed

Rakszewska, Agata; Stolper, Rosa J; Kolasa, Anna B; Piruska, Aigars; Huck, Wilhelm T S

2016-06-01

In recent years, technologies capable of analyzing single cells have emerged that are transforming many fields of biological research. Herein we report how DNA-functionalized hydrogel beads can serve as a matrix to capture mRNA from lysed single cells. mRNA quantification free of pre-amplification bias is ensured by using padlock probes and rolling circle amplification followed by hybridization with fluorescent probes. The number of transcripts in individual cells is assessed by simply counting fluorescent dots inside gel beads. The method extends the potential of existing techniques and provides a general platform for capturing molecules of interest from single cells. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Prediction of vortex shedding from circular and noncircular bodies in subsonic flow

NASA Technical Reports Server (NTRS)

Mendenhall, Michael R.; Lesieutre, Daniel J.

1987-01-01

An engineering prediction method and associated computer code VTXCLD are presented which predict nose vortex shedding from circular and noncircular bodies in subsonic flow at angles of attack and roll. The axisymmetric body is represented by point sources and doublets, and noncircular cross sections are transformed to a circle by either analytical or numerical conformal transformations. The leeward vortices are modeled by discrete vortices in crossflow planes along the body; thus, the three-dimensional steady flow problem is reduced to a two-dimensional, unsteady, separated flow problem for solution. Comparison of measured and predicted surface pressure distributions, flowfield surveys, and aerodynamic characteristics are presented for bodies with circular and noncircular cross sectional shapes.

Analysis of the Contribution to Professional Knowledge of the Job Training within the Student Perspective in the 3+1 Education Model--The Example of Honaz Vocational School

ERIC Educational Resources Information Center

Aksit, Adnan; Arpat, Bulent; Kalfa, Veli Riza

2017-01-01

A well-educated and qualified workforce is one of the most important outputs in vocational and technical education. Vocational schools constitute the last circle in Turkey for the preparing students about the vocational and technical education in order to meet the need for the intermediate staff needed by the labor market. The educational model…

Effects of Mode of Deformation and Extent of Reduction on Evolution of {111}-Fiber During Cold Rolling of Ni-16Cr Alloy

NASA Astrophysics Data System (ADS)

Mehta, K. K.; Mandal, R. K.; Singh, A. K.

2018-07-01

The high ratio of relative resolved shear stress on a twin to planar slip system results in microstructural latent hardening (some kind of overshooting) by the twin system on the primary slip planes, which leads to development of the {111}-fiber in Ni-16Cr alloy. The development of {111}-fiber starts as early as around 16 pct cold reduction in Ni-16Cr alloy and persists with maximum average intensity ranging from 35 to 40 pct additional deformation, i.e., around 50 pct cold reduction in unidirectional (U) and two-step cross (T)-rolling modes. In between 50 and 68 pct reductions in U and T modes, the fiber becomes unstable and starts disappearing. However, in multistep cross (M) rolling, the {111}-fiber formation starts late, i.e., at around 50 pct reduction, and maintains its stability up to additional deformation ranging from 35 to 40 pct, i.e., around 90 pct cold reduction. Thus, the life of {111}-fiber remains stable only within the range from 35 to 40 pct intermediate deformation during cold rolling of Ni-16Cr alloy irrespective of modes of rolling. However, the start and end of fiber stabilities depend on the modes of deformation by rolling. The maximum average intensity of {111}-fiber that can be attained in Ni-16Cr alloy is around 3.6× random in any of the deformation modes.

Effects of Mode of Deformation and Extent of Reduction on Evolution of {111}-Fiber During Cold Rolling of Ni-16Cr Alloy

NASA Astrophysics Data System (ADS)

Mehta, K. K.; Mandal, R. K.; Singh, A. K.

2018-04-01

The high ratio of relative resolved shear stress on a twin to planar slip system results in microstructural latent hardening (some kind of overshooting) by the twin system on the primary slip planes, which leads to development of the {111}-fiber in Ni-16Cr alloy. The development of {111}-fiber starts as early as around 16 pct cold reduction in Ni-16Cr alloy and persists with maximum average intensity ranging from 35 to 40 pct additional deformation, i.e., around 50 pct cold reduction in unidirectional (U) and two-step cross (T)-rolling modes. In between 50 and 68 pct reductions in U and T modes, the fiber becomes unstable and starts disappearing. However, in multistep cross (M) rolling, the {111}-fiber formation starts late, i.e., at around 50 pct reduction, and maintains its stability up to additional deformation ranging from 35 to 40 pct, i.e., around 90 pct cold reduction. Thus, the life of {111}-fiber remains stable only within the range from 35 to 40 pct intermediate deformation during cold rolling of Ni-16Cr alloy irrespective of modes of rolling. However, the start and end of fiber stabilities depend on the modes of deformation by rolling. The maximum average intensity of {111}-fiber that can be attained in Ni-16Cr alloy is around 3.6× random in any of the deformation modes.

Sensitive detection of T4 polynucleotide kinase activity based on multifunctional magnetic probes and polymerization nicking reactions mediated hyperbranched rolling circle amplification.

PubMed

Li, Xia; Xu, Xiaowen; Song, Juan; Xue, Qingwang; Li, Chenzhong; Jiang, Wei

2017-05-15

T4 polynucleotide kinase (PNK) plays critical roles in regulating DNA phosphorylation modes during the repair of DNA lesions. The aberrant activity of T4 PNK has been proven to be associated with a variety of human pathologies. Sensitive detection of T4 PNK activity is critical to both clinical diagnosis and therapeutics. Herein, a background-eliminated fluorescence assay for sensitive detection of T4 PNK activity has been developed by multifunctional magnetic probes and polymerization nicking reactions mediated hyperbranched rolling circle amplification (HRCA). First, the streptavidin-magnetic nanobeads (MBs) were functionalized with the biotin modified hairpin probe (HP) with 3'-phosphoryl, forming multifunctional magnetic probes (HP-MBs). Then, in the presence of T4 PNK, the 3'-phosphoryl of HP-MBs was hydrolyzed to 3'-hydroxyl, thus serving as primers to initiate the polymerization extension and nicking endonuclease cleavage reaction. Next, the primers released from above "polymerization-nicking" cycles were separated out to trigger the subsequently HRCA process, producing plenty of dsDNA. Finally, the intercalating dye SYBR Green I (SG) was inserted into the dsDNA, generating enhanced fluorescence signals. In our design, the HP-MBs here serve together as the T4 PNK, DNA polymerase, and endonuclease recognition probe, and thus avoid the demands of utilizing multiple probes design. Moreover, it performed primary "polymerization-nicking" amplification and mediate secondary HRCA. In addition to, performing the separation function, the binding of HP-MBs and SG could be avoided while a low background was acquired. This method showed excellent sensitivity with a detection limit of 0.0436 mU/mL, and accomplished exceptional characterization T4 PNK activity in cell extracts, offering a powerful tool for biomedical research and clinical diagnosis. Copyright © 2017 Elsevier B.V. All rights reserved.

Characterization of replication and conjugation of plasmid pWTY27 from a widely distributed Streptomyces species

PubMed Central

2012-01-01

Background Streptomyces species are widely distributed in natural habitats, such as soils, lakes, plants and some extreme environments. Replication loci of several Streptomyces theta-type plasmids have been reported, but are not characterized in details. Conjugation loci of some Streptomyces rolling-circle-type plasmids are identified and mechanism of conjugal transferring are described. Results We report the detection of a widely distributed Streptomyces strain Y27 and its indigenous plasmid pWTY27 from fourteen plants and four soil samples cross China by both culturing and nonculturing methods. The complete nucleotide sequence of pWTY27 consisted of 14,288 bp. A basic locus for plasmid replication comprised repAB genes and an adjacent iteron sequence, to a long inverted-repeat (ca. 105 bp) of which the RepA protein bound specifically in vitro, suggesting that RepA may recognize a second structure (e.g. a long stem-loop) of the iteron DNA. A plasmid containing the locus propagated in linear mode when the telomeres of a linear plasmid were attached, indicating a bi-directional replication mode for pWTY27. As for rolling-circle plasmids, a single traA gene and a clt sequence (covering 16 bp within traA and its adjacent 159 bp) on pWTY27 were required for plasmid transfer. TraA recognized and bound specifically to the two regions of the clt sequence, one containing all the four DC1 of 7 bp (TGACACC) and one DC2 (CCCGCCC) and most of IC1, and another covering two DC2 and part of IC1, suggesting formation of a high-ordered DNA-protein complex. Conclusions This work (i) isolates a widespread Streptomyces strain Y27 and sequences its indigenous theta-type plasmid pWTY27; (ii) identifies the replication and conjugation loci of pWTY27 and; (iii) characterizes the binding sequences of the RepA and TraA proteins. PMID:23134842

75 FR 16655 - Airworthiness Directives; Rolls-Royce plc RB211-Trent 700 Series Turbofan Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-02

... pressure (HP-IP) turbine internal and external oil vent tubes for coking and carbon buildup, and cleaning... borescope inspections of the HP-IP turbine internal and external oil vent tubes for coking and carbon...-intermediate pressure (HP-IP) turbine internal oil vent tubes, external oil vent tubes, and bearing chamber...

Carbon nanotube enhanced label-free detection of microRNAs based on hairpin probe triggered solid-phase rolling-circle amplification

NASA Astrophysics Data System (ADS)

Tian, Qianqian; Wang, Ying; Deng, Ruijie; Lin, Lei; Liu, Yang; Li, Jinghong

2014-12-01

The detection of microRNAs (miRNAs) is imperative for gaining a better understanding of the functions of these biomarkers and has great potential for the early diagnosis of human disease. High sensitivity and selectivity for miRNA detection brings new challenges. Herein, an ultrasensitive protocol for electrochemical detection of miRNA is designed through carbon nanotube (CNT) enhanced label-free detection based on hairpin probe triggered solid-phase rolling-circle amplification (RCA). Traditionally, RCA, widely applied for signal enhancement in the construction of a variety of biosensors, has an intrinsic limitation of ultrasensitive detection, as it is difficult to separate the enzymes, templates, and padlock DNAs from the RCA products in the homogeneous solution. We purposely designed a solid-phase RCA strategy, using CNTs as the solid substrate, integrated with a hairpin structured probe to recognize target miRNA. In the presence of miRNA the stem-loop structure will be unfolded, triggering the CNT based RCA process. Due to the efficient blocking effect originating from the polymeric RCA products, the label-free assay of miRNA exhibits an ultrasensitive detection limit of 1.2 fM. Furthermore, the protocol possesses excellent specificity for resolving lung cancer-related let-7 family members which have only one-nucleotide variations. The high sensitivity and selectivity give the method great potential for applications in online diagnostics and in situ detection in long-term development.The detection of microRNAs (miRNAs) is imperative for gaining a better understanding of the functions of these biomarkers and has great potential for the early diagnosis of human disease. High sensitivity and selectivity for miRNA detection brings new challenges. Herein, an ultrasensitive protocol for electrochemical detection of miRNA is designed through carbon nanotube (CNT) enhanced label-free detection based on hairpin probe triggered solid-phase rolling-circle amplification (RCA). Traditionally, RCA, widely applied for signal enhancement in the construction of a variety of biosensors, has an intrinsic limitation of ultrasensitive detection, as it is difficult to separate the enzymes, templates, and padlock DNAs from the RCA products in the homogeneous solution. We purposely designed a solid-phase RCA strategy, using CNTs as the solid substrate, integrated with a hairpin structured probe to recognize target miRNA. In the presence of miRNA the stem-loop structure will be unfolded, triggering the CNT based RCA process. Due to the efficient blocking effect originating from the polymeric RCA products, the label-free assay of miRNA exhibits an ultrasensitive detection limit of 1.2 fM. Furthermore, the protocol possesses excellent specificity for resolving lung cancer-related let-7 family members which have only one-nucleotide variations. The high sensitivity and selectivity give the method great potential for applications in online diagnostics and in situ detection in long-term development. Electronic supplementary information (ESI) available: Preparation of the chemically modified multi-walled carbon nanotubes (CNTs), characterization of the CNTs and modified CNTs, preparation of the circular probe, gel electrophoresis of the RCA products, and DNA probes as noted in the text. See DOI: 10.1039/c4nr05243a

Method of manufacturing metallic products such as sheet by cold working and flash anealing

DOEpatents

Hajaligol, Mohammad R.; Sikka, Vinod K.

2001-01-01

A metallic alloy composition is manufactured into products such as press formed or stamped products or rolled products such as sheet, strip, rod, wire or band by one or more cold working steps with intermediate or final flash annealing. The method can include cold rolling an iron, nickel or titanium aluminide alloy and annealing the cold worked product in a furnace by infrared heating. The flash annealing is preferably carried out by rapidly heating the cold worked product to an elevated temperature for less than one minute. The flash annealing is effective to reduce surface hardness of the cold worked product sufficiently to allow further cold working. The product to be cold worked can be prepared by casting the alloy or by a powder metallurgical technique such as tape casting a mixture of metal powder and a binder, roll compacting a mixture of the powder and a binder or plasma spraying the powder onto a substrate. In the case of tape casting or roll compaction, the initial powder product can be heated to a temperature sufficient to remove volatile components. The method can be used to form a cold rolled sheet which is formed into an electrical resistance heating element capable of heating to 900.degree. C. in less than 1 second when a voltage up to 10 volts and up to 6 amps is passed through the heating element.

Method of manufacturing metallic products such as sheet by cold working and flash annealing

DOEpatents

Hajaligol, Mohammad R.; Sikka, Vinod K.

2000-01-01

A metallic alloy composition is manufactured into products such as press formed or stamped products or rolled products such as sheet, strip, rod, wire or band by one or more cold working steps with intermediate or final flash annealing. The method can include cold rolling an iron, nickel or titanium aluminide alloy and annealing the cold worked product in a furnace by infrared heating. The flash annealing is preferably carried out by rapidly heating the cold worked product to an elevated temperature for less than one minute. The flash annealing is effective to reduce surface hardness of the cold worked product sufficiently to allow further cold working. The product to be cold worked can be prepared by casting the alloy or by a powder metallurgical technique such as tape casting a mixture of metal powder and a binder, roll compacting a mixture of the powder and a binder or plasma spraying the powder onto a substrate. In the case of tape casting or roll compaction, the initial powder product can be heated to a temperature sufficient to remove volatile components. The method can be used to form a cold rolled sheet which is formed into an electrical resistance heating element capable of heating to 900.degree. C. in less than 1 second when a voltage up to 10 volts and up to 6 amps is passed through the heating element.

The relationship between leaf rolling and ascorbate-glutathione cycle enzymes in apoplastic and symplastic areas of Ctenanthe setosa subjected to drought stress.

PubMed

Saruhan, Neslihan; Terzi, Rabiye; Saglam, Aykut; Kadioglu, Asim

2009-01-01

The ascorbate-glutathione (ASC-GSH) cycle has an important role in defensive processes against oxidative damage generated by drought stress. In this study, the changes that take place in apoplastic and symplastic ASC-GSH cycle enzymes of the leaf and petiole were investigated under drought stress causing leaf rolling in Ctenanthe setosa (Rose.) Eichler (Marantaceae). Apoplastic and symplastic extractions of leaf and petiole were performed at different visual leaf rolling scores from 1 to 4 (1 is unrolled, 4 is tightly rolled and the others are intermediate forms). Glutathione reductase (GR), a key enzyme in the GSH regeneration cycle, and ascorbate (ASC) were present in apoplastic spaces of the leaf and petiole, whereas dehydroascorbate reductase (DHAR), which uses glutathione as reductant, monodehydroascorbate reductase (MDHAR), which uses NAD(P)H as reductant, and glutathione were absent. GR, DHAR and MDHAR activities increased in the symplastic and apoplastic areas of the leaf. Apoplastic and symplastic ASC and dehydroascorbate (DHA), the oxidized form of ascorbate, rose at all scores except score 4 of symplastic ASC in the leaf. On the other hand, while reduced glutathione (GSH) content was enhanced, oxidized glutathione (GSSG) content decreased in the leaf during rolling. As for the petiole, GR activity increased in the apoplastic area but decreased in the symplastic area. DHAR and MDHAR activities increased throughout all scores, but decreased to the score 1 level at score 4. The ASC content of the apoplast increased during leaf rolling. Conversely, symplastic ASC content increased at score 2, however decreased at the later scores. While the apoplastic DHA content declined, symplastic DHA rose at score 2, but later was down to the level of score 1. While GSH content enhanced during leaf rolling, GSSG content did not change except at score 2. As well, there were good correlations between leaf rolling and ASC-GSH cycle enzyme activities in the leaf (GR and DHAR) and leaf rolling and GSSG. These results showed that in apoplastic and symplastic areas, ASC-GSH cycle enzymes leading ROS detoxification may have a role in controlling leaf rolling.

12. RW Meyer Sugar Mill: 18761889. Threeroll sugar mill: oneton ...

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

12. RW Meyer Sugar Mill: 1876-1889. Three-roll sugar mill: one-ton daily processing capacity. Manufactured by Edwin Maw, Liverpool, England, ca. 1855-1870. View: Historical view, 1934, T.T. Waterman Collection, Hawaiian Sugar Planters' Association, Oahu, Hawaii. Masonry-lined passageway leading to the mill at the center of its circular masonry enclosure. The passageway permitted cane to be carried to the mill and cane trash (bagasse) to be carried away after milling. Bridges over the passageways, not in place, permitted the mill animals to circle and power the mill from above. View shows area prior to substantial overgrowth existing in 1978 views of the area. - R. W. Meyer Sugar Mill, State Route 47, Kualapuu, Maui County, HI

Prediction of subsonic vortex shedding from forebodies with chines

NASA Technical Reports Server (NTRS)

Mendenhall, Michael R.; Lesieutre, Daniel J.

1990-01-01

An engineering prediction method and associated computer code VTXCHN to predict nose vortex shedding from circular and noncircular forebodies with sharp chine edges in subsonic flow at angles of attack and roll are presented. Axisymmetric bodies are represented by point sources and doublets, and noncircular cross sections are transformed to a circle by either analytical or numerical conformal transformations. The lee side vortex wake is modeled by discrete vortices in crossflow planes along the body; thus the three-dimensional steady flow problem is reduced to a two-dimensional, unsteady, separated flow problem for solution. Comparison of measured and predicted surface pressure distributions, flow field surveys, and aerodynamic characteristics are presented for noncircular bodies alone and forebodies with sharp chines.

Novel Polyomavirus associated with Brain Tumors in Free-Ranging Raccoons, Western United States

PubMed Central

Dela Cruz, Florante N.; Giannitti, Federico; Li, Linlin; Woods, Leslie W.; Del Valle, Luis; Delwart, Eric

2013-01-01

Tumors of any type are exceedingly rare in raccoons. High-grade brain tumors, consistently located in the frontal lobes and olfactory tracts, were detected in 10 raccoons during March 2010–May 2012 in California and Oregon, suggesting an emerging, infectious origin. We have identified a candidate etiologic agent, dubbed raccoon polyomavirus, that was present in the tumor tissue of all affected animals but not in tissues from 20 unaffected animals. Southern blot hybridization and rolling circle amplification showed the episomal viral genome in the tumors. The multifunctional nuclear protein large T-antigen was detectable by immunohistochemical analyses in a subset of neoplastic cells. Raccoon polyomavirus may contribute to the development of malignant brain tumors of raccoons. PMID:23260029

Novel polyomavirus associated with brain tumors in free-ranging raccoons, western United States.

PubMed

Dela Cruz, Florante N; Giannitti, Federico; Li, Linlin; Woods, Leslie W; Del Valle, Luis; Delwart, Eric; Pesavento, Patricia A

2013-01-01

Tumors of any type are exceedingly rare in raccoons. High-grade brain tumors, consistently located in the frontal lobes and olfactory tracts, were detected in 10 raccoons during March 2010-May 2012 in California and Oregon, suggesting an emerging, infectious origin. We have identified a candidate etiologic agent, dubbed raccoon polyomavirus, that was present in the tumor tissue of all affected animals but not in tissues from 20 unaffected animals. Southern blot hybridization and rolling circle amplification showed the episomal viral genome in the tumors. The multifunctional nuclear protein large T-antigen was detectable by immunohistochemical analyses in a subset of neoplastic cells. Raccoon polyomavirus may contribute to the development of malignant brain tumors of raccoons.

Origins and evolution of viruses of eukaryotes: The ultimate modularity

PubMed Central

Koonin, Eugene V.; Dolja, Valerian V.; Krupovic, Mart

2018-01-01

Viruses and other selfish genetic elements are dominant entities in the biosphere, with respect to both physical abundance and genetic diversity. Various selfish elements parasitize on all cellular life forms. The relative abundances of different classes of viruses are dramatically different between prokaryotes and eukaryotes. In prokaryotes, the great majority of viruses possess double-stranded (ds) DNA genomes, with a substantial minority of single-stranded (ss) DNA viruses and only limited presence of RNA viruses. In contrast, in eukaryotes, RNA viruses account for the majority of the virome diversity although ssDNA and dsDNA viruses are common as well. Phylogenomic analysis yields tangible clues for the origins of major classes of eukaryotic viruses and in particular their likely roots in prokaryotes. Specifically, the ancestral genome of positive-strand RNA viruses of eukaryotes might have been assembled de novo from genes derived from prokaryotic retroelements and bacteria although a primordial origin of this class of viruses cannot be ruled out. Different groups of double-stranded RNA viruses derive either from dsRNA bacteriophages or from positive-strand RNA viruses. The eukaryotic ssDNA viruses apparently evolved via a fusion of genes from prokaryotic rolling circle-replicating plasmids and positive-strand RNA viruses. Different families of eukaryotic dsDNA viruses appear to have originated from specific groups of bacteriophages on at least two independent occasions. Polintons, the largest known eukaryotic transposons, predicted to also form virus particles, most likely, were the evolutionary intermediates between bacterial tectiviruses and several groups of eukaryotic dsDNA viruses including the proposed order “Megavirales” that unites diverse families of large and giant viruses. Strikingly, evolution of all classes of eukaryotic viruses appears to have involved fusion between structural and replicative gene modules derived from different sources along with additional acquisitions of diverse genes. PMID:25771806

Giant Reverse Transcriptase-Encoding Transposable Elements at Telomeres.

PubMed

Arkhipova, Irina R; Yushenova, Irina A; Rodriguez, Fernando

2017-09-01

Transposable elements are omnipresent in eukaryotic genomes and have a profound impact on chromosome structure, function and evolution. Their structural and functional diversity is thought to be reasonably well-understood, especially in retroelements, which transpose via an RNA intermediate copied into cDNA by the element-encoded reverse transcriptase, and are characterized by a compact structure. Here, we report a novel type of expandable eukaryotic retroelements, which we call Terminons. These elements can attach to G-rich telomeric repeat overhangs at the chromosome ends, in a process apparently facilitated by complementary C-rich repeats at the 3'-end of the RNA template immediately adjacent to a hammerhead ribozyme motif. Terminon units, which can exceed 40 kb in length, display an unusually complex and diverse structure, and can form very long chains, with host genes often captured between units. As the principal polymerizing component, Terminons contain Athena reverse transcriptases previously described in bdelloid rotifers and belonging to the enigmatic group of Penelope-like elements, but can additionally accumulate multiple cooriented ORFs, including DEDDy 3'-exonucleases, GDSL esterases/lipases, GIY-YIG-like endonucleases, rolling-circle replication initiator (Rep) proteins, and putatively structural ORFs with coiled-coil motifs and transmembrane domains. The extraordinary length and complexity of Terminons and the high degree of interfamily variability in their ORF content challenge the current views on the structural organization of eukaryotic retroelements, and highlight their possible connections with the viral world and the implications for the elevated frequency of gene transfer. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Isolation of a novel plasmid from Couchioplanes caeruleus and construction of two plasmid vectors for gene expression in Actinoplanes missouriensis.

PubMed

Jang, Moon-Sun; Fujita, Azusa; Ikawa, Satomi; Hanawa, Keitaro; Yamamura, Hideki; Tamura, Tomohiko; Hayakawa, Masayuki; Tezuka, Takeaki; Ohnishi, Yasuo

2015-01-01

To date, no plasmid vector has been developed for the rare actinomycete Actinoplanes missouriensis. Moreover, no small circular plasmid has been reported to exist in the genus Actinoplanes. Here, a novel plasmid, designated pCAZ1, was isolated from Couchioplanes caeruleus subsp. azureus via screening for small circular plasmids in Actinoplanes (57 strains) and Couchioplanes (2 strains). Nucleotide sequencing revealed that pCAZ1 is a 5845-bp circular molecule with a G + C content of 67.5%. The pCAZ1 copy number was estimated at 30 per chromosome. pCAZ1 contains seven putative open reading frames, one of which encodes a protein containing three motifs conserved among plasmid-encoded replication proteins that are involved in the rolling-circle mechanism of replication. Detection of single-stranded DNA intermediates in C. caeruleus confirmed that pCAZ1 replicates by this mechanism. The ColE1 origin from pBluescript SK(+) and the oriT sequence with the apramycin resistance gene aac(3)IV from pIJ773 were inserted together into pCAZ1, to construct the Escherichia coli-A. missouriensis shuttle vectors, pCAM1 and pCAM2, in which the foreign DNA fragment was inserted into pCAZ1 in opposite directions. pCAM1 and pCAM2 were successfully transferred to A. missouriensis through the E. coli-mediated conjugative transfer system. The copy numbers of pCAM1 and pCAM2 in A. missouriensis were estimated to be one and four per chromosome, respectively. Thus, these vectors can be used as effective genetic tools for homologous and heterologous gene expression studies in A. missouriensis. Copyright © 2014 Elsevier Inc. All rights reserved.

FUEL ELEMENT FOR NEUTRONIC REACTORS

DOEpatents

Evans, T.C.; Beasley, E.G.

1961-01-17

A fuel element for neutronic reactors, particularly the gas-cooled type of reactor, is described. The element comprises a fuel-bearing plate rolled to form a cylinder having a spiral passageway passing from its periphery to its center. In operation a coolant is admitted to the passageway at the periphery of the element, is passed through the spiral passageway, and emerges into a central channel defined by the inner turn of the rolled plate. The advantage of the element is that the fully heated coolant (i.e., coolant emerging into the central channel) is separated and thus insulated from the periphery of the element, which may be in contact with a low-temperature moderator, by the intermediate turns of the spiral fuel element.

Chemically sensitive free-volume study of amorphization of Cu60Zr40 induced by cold rolling and folding

NASA Astrophysics Data System (ADS)

Puff, Werner; Rabitsch, Herbert; Wilde, Gerhard; Dinda, Guru P.; Würschum, Roland

2007-06-01

With the aim to contribute to a microscopical understanding of the processes of solid-state amorphization, the chemically sensitive technique of background—reduced Doppler broadening of positron-electron annihilation radiation in combination with positron lifetime spectroscopy and microstructural characterization is applied to a free volume study of the amorphization of Cu60Zr40 induced by consecutive folding and rolling. Starting from the constituent pure metal foils, a nanosale multilayer structure of elemental layers and amorphous interlayers develops in an intermediate state of folding and rolling, where free volumes with a Zr-rich environment occur presumably located in the hetero-interfaces between the various layers or in grain boundaries of the Cu layers. After complete intermixing and amorphization, the local chemical environment of the free volumes reflects the average chemical alloy composition. In contrast to other processes of amorphization, free volumes of the size of few missing atoms occur in the rolling-induced amorphous state. Self-consistent results from three different methods for analyzing the Doppler broadening spectra, i.e., S-W-parameter correlation, multicomponent fit, and the shape of ratio curves, demonstrate the potential of the background-reduced Doppler technique for chemically sensitive characterization of structurally complex materials on an atomic scale.

Structural, magnetic and impedance spectroscopic analysis of LaFeO3 nano-particles

NASA Astrophysics Data System (ADS)

Rao, T. Lakshmana; Pradhan, M. K.; Dash, S.

2018-04-01

Physical properties are known to be drastically varied with crystallite size and in a multifunctional material this size reduction is seem to be interesting. One such material is chosen as LaFeO3 nanoparticles which have been prepared by wet-chemical route. The average particle size found to be in the order of 45nm in which the chemical content of the unit cell has been verified. A distorted orthorhombic structure with Pbnm space group is possessed by this nanoparticle. From the bifurcation of ZFC and FC in low field, behavior of inverse susceptibility and the small hysteresis loop favors the material to be in a weak FM state well below the Neel temperature. The electrical behavior and the conduction mechanism above room temperature have been studied by cole-cole plot of the Impedance spectra. The high frequency depressed semi circles represent the grain conduction while the intermediate frequency semi circles appear may be due to grain boundary effect.

Behavior of sheets from Ti-alloys by rolling and heat treatment

NASA Astrophysics Data System (ADS)

Isaenkova, M.; Perlovich, Yu.; Fesenko, V.; Gritskevich, M.; Stolbov, S.; Zaripova, M.

2017-10-01

Sheets from single- and two-phase Ti-alloys (VT1-0, Ti-22Nb-9%Zr and VT-16) were rolled at the room temperature up to various deformation degrees and annealed at temperatures 500-900 °C. The regularities of texture formation in both phases were established. In the technically pure Ti (VT1-0) with the single α-Ti phase the final stable texture component is (0001)±30-40°ND-TD<101 ¯0>. In the two-phase alloy the reorientation of basal axes of α-Ti occurs by the same trajectories as in the single phase alloy. However, in the case of two-phase alloy texture development in α-Ti stops at the intermediate stage, when this texture consists of components with rolling planes (0001)±15-20°ND-RD and (0001)±30-40°ND-TD. The stability of the first components can be provided both by the mutually balanced operation of pyramidal and basal slip systems, activity of which remains at the high deformation degree of two-phase alloy, and by the dynamic α↔β phase transformations, taking place in the distorted structures of α- and β-phases in the course of its cold rolling. At recrystallization of technically pure Ti the basal component disappears in its texture. At the same time, prismatic axes turn by angles 20÷30° depending on the heating rate of the rolled sheet and annealing temperature. At recrystallization of the two-phase Ti-alloy prismatic axes of its α-grains doesn't turn relative to their positions in the rolling texture, as it occurs in the single-phase alloy. This fact indicates to some alternative mode of arising new recrystallized grains in two-phase alloys.

A quality by design approach to investigate the effect of mannitol and dicalcium phosphate qualities on roll compaction.

PubMed

Souihi, Nabil; Dumarey, Melanie; Wikström, Håkan; Tajarobi, Pirjo; Fransson, Magnus; Svensson, Olof; Josefson, Mats; Trygg, Johan

2013-04-15

Roll compaction is a continuous process for solid dosage form manufacturing increasingly popular within pharmaceutical industry. Although roll compaction has become an established technique for dry granulation, the influence of material properties is still not fully understood. In this study, a quality by design (QbD) approach was utilized, not only to understand the influence of different qualities of mannitol and dicalcium phosphate (DCP), but also to predict critical quality attributes of the drug product based solely on the material properties of that filler. By describing each filler quality in terms of several representative physical properties, orthogonal projections to latent structures (OPLS) was used to understand and predict how those properties affected drug product intermediates as well as critical quality attributes of the final drug product. These models were then validated by predicting product attributes for filler qualities not used in the model construction. The results of this study confirmed that the tensile strength reduction, known to affect plastic materials when roll compacted, is not prominent when using brittle materials. Some qualities of these fillers actually demonstrated improved compactability following roll compaction. While direct compression qualities are frequently used for roll compacted drug products because of their excellent flowability and good compaction properties, this study revealed that granules from these qualities were more poor flowing than the corresponding powder blends, which was not seen for granules from traditional qualities. The QbD approach used in this study could be extended beyond fillers. Thus any new compound/ingredient would first be characterized and then suitable formulation characteristics could be determined in silico, without running any additional experiments. Copyright © 2013 Elsevier B.V. All rights reserved.

Phenomenological implications of the blown-up orbifolds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cvetic, M.

1987-05-01

We discuss the structure of the effective Lagrangian for the (2,2) Z/sub N/ orbifolds and the corresponding Calabi-Yau manifolds which are obtained by ''blowing-up'' the orbifold singularities. The method to ''blow-up'' such singularities is reviewed. Results are exact at the string tree-level. In particular, the question of generating an intermediate scale M/sub I/ in such models is addressed. It is shown that for Z/sub N/ orbifolds (except one) and the corresponding blown-up orbifolds which are compactified on any six-torus T/sup 6/ which can be obtained by continuously deforming T/sup 4/ circle times T/sup 2/, all the terms of the typemore » (2727)/sup K/ are absent from the effective superpotential, thus questioning the mechanism for generating a large intermediate scale for such compactifications.« less

Simplified methods for the construction of RNA and DNA virus infectious clones.

PubMed

Nagata, Tatsuya; Inoue-Nagata, Alice Kazuko

2015-01-01

Infectious virus clones are one of the most powerful tools in plant pathology, molecular biology, and biotechnology. The construction of infectious clones of RNA and DNA viruses, however, usually requires laborious cloning and subcloning steps. In addition, instability of the RNA virus genome is frequently reported after its introduction into the vector and transference to Escherichia coli. These difficulties hamper the cloning procedures, making it tedious and cumbersome. This chapter describes two protocols for a simple construction of infectious viruses, an RNA virus, the tobamovirus Pepper mild mottle virus, and a DNA virus, a bipartite begomovirus. For this purpose, the strategy of overlap-extension PCR was used for the construction of infectious tobamovirus clone and of rolling circle amplification (RCA) for the construction of a dimeric form of the begomovirus clone.

Enzymatic Synthesis of Self-assembled Dicer Substrate RNA Nanostructures for Programmable Gene Silencing.

PubMed

Jang, Bora; Kim, Boyoung; Kim, Hyunsook; Kwon, Hyokyoung; Kim, Minjeong; Seo, Yunmi; Colas, Marion; Jeong, Hansaem; Jeong, Eun Hye; Lee, Kyuri; Lee, Hyukjin

2018-06-08

Enzymatic synthesis of RNA nanostructures is achieved by isothermal rolling circle transcription (RCT). Each arm of RNA nanostructures provides a functional role of Dicer substrate RNA inducing sequence specific RNA interference (RNAi). Three different RNAi sequences (GFP, RFP, and BFP) are incorporated within the three-arm junction RNA nanostructures (Y-RNA). The template and helper DNA strands are designed for the large-scale in vitro synthesis of RNA strands to prepare self-assembled Y-RNA. Interestingly, Dicer processing of Y-RNA is highly influenced by its physical structure and different gene silencing activity is achieved depending on its arm length and overhang. In addition, enzymatic synthesis allows the preparation of various Y-RNA structures using a single DNA template offering on demand regulation of multiple target genes.

Label-free electrical detection of pyrophosphate generated from DNA polymerase reactions on field-effect devices.

PubMed

Credo, Grace M; Su, Xing; Wu, Kai; Elibol, Oguz H; Liu, David J; Reddy, Bobby; Tsai, Ta-Wei; Dorvel, Brian R; Daniels, Jonathan S; Bashir, Rashid; Varma, Madoo

2012-03-21

We introduce a label-free approach for sensing polymerase reactions on deoxyribonucleic acid (DNA) using a chelator-modified silicon-on-insulator field-effect transistor (SOI-FET) that exhibits selective and reversible electrical response to pyrophosphate anions. The chemical modification of the sensor surface was designed to include rolling-circle amplification (RCA) DNA colonies for locally enhanced pyrophosphate (PPi) signal generation and sensors with immobilized chelators for capture and surface-sensitive detection of diffusible reaction by-products. While detecting arrays of enzymatic base incorporation reactions is typically accomplished using optical fluorescence or chemiluminescence techniques, our results suggest that it is possible to develop scalable and portable PPi-specific sensors and platforms for broad biomedical applications such as DNA sequencing and microbe detection using surface-sensitive electrical readout techniques.

Shelf life and safety concerns of bakery products--a review.

PubMed

Smith, James P; Daifas, Daphne Phillips; El-Khoury, Wassim; Koukoutsis, John; El-Khoury, Anis

2004-01-01

Bakery products are an important part of a balanced diet and, today, a wide variety of such products can be found on supermarket shelves. This includes unsweetened goods (bread, rolls, buns, crumpets, muffins and bagels), sweet goods (pancakes, doughnuts, waffles and cookies) and filled goods (fruit and meat pies, sausage rolls, pastries, sandwiches, cream cakes, pizza and quiche). However, bakery products, like many processed foods, are subject to physical, chemical and microbiological spoilage. While physical and chemical spoilage limits the shelf life of low and intermediate moisture bakery products, microbiological spoilage by bacteria, yeast and molds is the concern in high moisture products i.e., products with a water activity (a(w)) > 0.85. Furthermore, several bakery products also have been implicated infoodborne illnesses involving Salmonella spp., Listeria monoctyogenes and Bacillus cereus, while Clostridium botulinum is a concern in high moisture bakery products packaged under modified atmospheres. This extensive review is divided into two parts. Part I focuses on the spoilage concerns of low, intermediate and high moisture bakery products while Part II focuses on the safety concerns of high moisture bakery products only. In both parts, traditional and novel methods of food preservation that can be used by the bakery industry to extend the shelf life and enhance the safety of products are discussed in detail.

Intermediate inflation from a non-canonical scalar field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rezazadeh, K.; Karami, K.; Karimi, P., E-mail: rezazadeh86@gmail.com, E-mail: KKarami@uok.ac.ir, E-mail: parvin.karimi67@yahoo.com

2015-09-01

We study the intermediate inflation in a non-canonical scalar field framework with a power-like Lagrangian. We show that in contrast with the standard canonical intermediate inflation, our non-canonical model is compatible with the observational results of Planck 2015. Also, we estimate the equilateral non-Gaussianity parameter which is in well agreement with the prediction of Planck 2015. Then, we obtain an approximation for the energy scale at the initial time of inflation and show that it can be of order of the Planck energy scale, i.e. M{sub P} ∼ 10{sup 18}GeV. We will see that after a short period of time, inflation entersmore » in the slow-roll regime that its energy scale is of order M{sub P}/100 ∼ 10{sup 16}GeV and the horizon exit takes place in this energy scale. We also examine an idea in our non-canonical model to overcome the central drawback of intermediate inflation which is the fact that inflation never ends. We solve this problem without disturbing significantly the nature of the intermediate inflation until the time of horizon exit.« less

Indications of Intermediate-scale Anisotropy of Cosmic Rays with Energy Greater Than 57 EeV in the Northern Sky Measured with the Surface Detector of the Telescope Array Experiment

NASA Astrophysics Data System (ADS)

Abbasi, R. U.; Abe, M.; Abu-Zayyad, T.; Allen, M.; Anderson, R.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Chae, M. J.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Cho, W. R.; Fujii, T.; Fukushima, M.; Goto, T.; Hanlon, W.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Honda, K.; Ikeda, D.; Inoue, N.; Ishii, T.; Ishimori, R.; Ito, H.; Ivanov, D.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kawata, K.; Kido, E.; Kim, H. B.; Kim, J. H.; Kim, J. H.; Kitamura, S.; Kitamura, Y.; Kuzmin, V.; Kwon, Y. J.; Lan, J.; Lim, S. I.; Lundquist, J. P.; Machida, K.; Martens, K.; Matsuda, T.; Matsuyama, T.; Matthews, J. N.; Minamino, M.; Mukai, K.; Myers, I.; Nagasawa, K.; Nagataki, S.; Nakamura, T.; Nonaka, T.; Nozato, A.; Ogio, S.; Ogura, J.; Ohnishi, M.; Ohoka, H.; Oki, K.; Okuda, T.; Ono, M.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Sakurai, N.; Sampson, A. L.; Scott, L. M.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Smith, J. D.; Sokolsky, P.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Stroman, T. A.; Suzawa, T.; Takamura, M.; Takeda, M.; Takeishi, R.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Uchihori, Y.; Udo, S.; Urban, F.; Vasiloff, G.; Wong, T.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yashiro, K.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zollinger, R.; Zundel, Z.

2014-08-01

We have searched for intermediate-scale anisotropy in the arrival directions of ultrahigh-energy cosmic rays with energies above 57 EeV in the northern sky using data collected over a 5 yr period by the surface detector of the Telescope Array experiment. We report on a cluster of events that we call the hotspot, found by oversampling using 20° radius circles. The hotspot has a Li-Ma statistical significance of 5.1σ, and is centered at R.A. = 146.°7, decl. = 43.°2. The position of the hotspot is about 19° off of the supergalactic plane. The probability of a cluster of events of 5.1σ significance, appearing by chance in an isotropic cosmic-ray sky, is estimated to be 3.7 × 10-4 (3.4σ).

Rapid detection of IHNV by molecular padlock recognition and surface-associated isothermal amplification

NASA Astrophysics Data System (ADS)

McCarthy, Erik L.; Egeler, Teressa J.; Bickerstaff, Lee E.; Pereira da Cunha, Mauricio; Millard, Paul J.

2005-11-01

RNA sequences derived from infectious hematopoeitic necrosis virus (IHNV) could be detected using a combination of surface-associated molecular padlock DNA probes (MPP) and rolling circle amplification (RCA) in microcapillary tubes. DNA oligonucleotides with base sequences identical to RNA obtained from IHNV were recognized by MPP. Circularized MPP were then captured on the inner surface of glass microcapillary tubes by immobilized DNA oligonucleotide primers. Extension of the immobilized primers by isothermal RCA gave rise to DNA concatamers, which were in turn bound by the fluorescent reporter SYBR Green II nucleic acid stain, and measured by microfluorimetry. Surface-associated molecular padlock technology, combined with isothermal RCA, exhibited high selectivity and sensitivity without thermal cycling. This technology is applicable to direct RNA and DNA detection, permitting detection of a variety of viral or bacterial pathogens.

A simple and efficient method for agroinfection of Vernonia cinerea with infectious clones of Vernonia yellow vein virus.

PubMed

Packialakshmi, R M; Usha, R

2011-12-01

Vernonia yellow vein virus (VeYVV) is a distinct monopartite begomovirus associated with a satellite DNA β. After constructing dimers of both DNA A and DNA β in binary vectors, a number of infection methods were attempted. However, only a modified stem-prick method produced up to 83% infection in the natural host Vernonia cinerea, thus, fulfilling the Koch's postulate. The presence of the viral DNA in the agroinfected plants was confirmed by rolling circle amplification (RCA), followed by Southern hybridization. DNA β induces typical symptoms of Vernonia yellow vein disease (VeYVD) when co-agroinoculated with the begomovirus to Vernonia and also leads to the accumulation of DNA A systemically. VeYVV represents a new member of the emerging group of monopartite begomoviruses requiring a satellite component for symptom induction.

Dissociable roles of medial and lateral PFC in rule learning.

PubMed

Cao, Bihua; Li, Wei; Li, Fuhong; Li, Hong

2016-11-01

Although the neural basis of rule learning is of great interest to cognitive neuroscientists, the pattern of transient brain activation during rule discovery remains to be investigated. In this study, we measured event-related functional magnetic resonance imaging (fMRI) during distinct phases of rule learning. Twenty-one healthy human volunteers were presented with a series of cards, each containing a clock-like display of 12 circles numbered sequentially. Participants were instructed that a fictitious animal would move from one circle to another either in a regular pattern (according to a rule hidden in consecutive trials) or randomly. Participants were then asked to judge whether a given step followed a rule. While the rule-search phase evoked more activation in the posterior lateral prefrontal cortex (LPFC), the rule-following phase caused stronger activation in the anterior medial prefrontal cortex (MPFC). Importantly, the intermediate phase, the rule-discovery phase evoked more activations in MPFC and dorsal anterior cingulate cortex (dACC) than rule search, and more activations in LPFC than rule following. Therefore, we can conclude that the medial and lateral PFC have dissociable contributions in rule learning.

The metamorphosis of supernova SN 2008D/XRF 080109: a link between supernovae and GRBs/hypernovae.

PubMed

Mazzali, Paolo A; Valenti, Stefano; Della Valle, Massimo; Chincarini, Guido; Sauer, Daniel N; Benetti, Stefano; Pian, Elena; Piran, Tsvi; D'Elia, Valerio; Elias-Rosa, Nancy; Margutti, Raffaella; Pasotti, Francesco; Antonelli, L Angelo; Bufano, Filomena; Campana, Sergio; Cappellaro, Enrico; Covino, Stefano; D'Avanzo, Paolo; Fiore, Fabrizio; Fugazza, Dino; Gilmozzi, Roberto; Hunter, Deborah; Maguire, Kate; Maiorano, Elisabetta; Marziani, Paola; Masetti, Nicola; Mirabel, Felix; Navasardyan, Hripsime; Nomoto, Ken'ichi; Palazzi, Eliana; Pastorello, Andrea; Panagia, Nino; Pellizza, L J; Sari, Re'em; Smartt, Stephen; Tagliaferri, Gianpiero; Tanaka, Masaomi; Taubenberger, Stefan; Tominaga, Nozomu; Trundle, Carrie; Turatto, Massimo

2008-08-29

The only supernovae (SNe) to show gamma-ray bursts (GRBs) or early x-ray emission thus far are overenergetic, broad-lined type Ic SNe (hypernovae, HNe). Recently, SN 2008D has shown several unusual features: (i) weak x-ray flash (XRF), (ii) an early, narrow optical peak, (iii) disappearance of the broad lines typical of SN Ic HNe, and (iv) development of helium lines as in SNe Ib. Detailed analysis shows that SN 2008D was not a normal supernova: Its explosion energy (E approximately 6x10(51) erg) and ejected mass [ approximately 7 times the mass of the Sun (M(middle dot in circle))] are intermediate between normal SNe Ibc and HNe. We conclude that SN 2008D was originally a approximately 30 M(middle dot in circle) star. When it collapsed, a black hole formed and a weak, mildly relativistic jet was produced, which caused the XRF. SN 2008D is probably among the weakest explosions that produce relativistic jets. Inner engine activity appears to be present whenever massive stars collapse to black holes.

Nucleosynthesis and the nova outburst

NASA Technical Reports Server (NTRS)

Starrfield, S.; Truran, J.W.; Wiescher, M.; Sparks, W.M.

1995-01-01

A nova outburst is the consequence of the accretion of hydrogen rich material onto a white dwarf and it can be considered as the largest hydrogen bomb in the Universe. The fuel is supplied by a secondary star in a close binary system while the strong degeneracy of the massive white dwarf acts to contain the gas during the early stages of the explosion. The containment allows the temperature in the nuclear burning region to exceed 10(sup 8)K under all circumstances. As a result a major fraction of CNO nuclei in the envelope are transformed into (beta)(sup +)-unstable nuclei. We discuss the effects of these nuclei on the evolution. Recent observational studies have shown that there are two compositional classes of novae; one which occurs on carbon-oxygen white dwarfs, and a second class that occurs on oxygen-neon-magnesium white dwarfs. In this review we will concentrate on the latter explosions since they produce the most interesting nucleosynthesis. We report both on the results of new observational determinations of nova abundances and, in addition, new hydrodynamic calculations that examine the consequences of the accretion process on 1.0M(sub (circle dot)), 1.25M(sub (circle dot)), and 1.35M(sub (circle dot)) white dwarfs. Our results show that novae can produce (sup 22)Na, (sup 26)Al, and other intermediate mass nuclei in interesting amounts. We will present the results of new calculations, done with updated nuclear reaction rates and opacities, which exhibit quantitative differences with respect to published work.

A study of correlations between crude oil spot and futures markets: A rolling sample test

NASA Astrophysics Data System (ADS)

Liu, Li; Wan, Jieqiu

2011-10-01

In this article, we investigate the asymmetries of exceedance correlations and cross-correlations between West Texas Intermediate (WTI) spot and futures markets. First, employing the test statistic proposed by Hong et al. [Asymmetries in stock returns: statistical tests and economic evaluation, Review of Financial Studies 20 (2007) 1547-1581], we find that the exceedance correlations were overall symmetric. However, the results from rolling windows show that some occasional events could induce the significant asymmetries of the exceedance correlations. Second, employing the test statistic proposed by Podobnik et al. [Quantifying cross-correlations using local and global detrending approaches, European Physics Journal B 71 (2009) 243-250], we find that the cross-correlations were significant even for large lagged orders. Using the detrended cross-correlation analysis proposed by Podobnik and Stanley [Detrended cross-correlation analysis: a new method for analyzing two nonstationary time series, Physics Review Letters 100 (2008) 084102], we find that the cross-correlations were weakly persistent and were stronger between spot and futures contract with larger maturity. Our results from rolling sample test also show the apparent effects of the exogenous events. Additionally, we have some relevant discussions on the obtained evidence.

Evolution of eukaryotic single-stranded DNA viruses of the Bidnaviridae family from genes of four other groups of widely different viruses

NASA Astrophysics Data System (ADS)

Krupovic, Mart; Koonin, Eugene V.

2014-06-01

Single-stranded (ss)DNA viruses are extremely widespread, infect diverse hosts from all three domains of life and include important pathogens. Most ssDNA viruses possess small genomes that replicate by the rolling-circle-like mechanism initiated by a distinct virus-encoded endonuclease. However, viruses of the family Bidnaviridae, instead of the endonuclease, encode a protein-primed type B DNA polymerase (PolB) and hence break this pattern. We investigated the provenance of all bidnavirus genes and uncover an unexpected turbulent evolutionary history of these unique viruses. Our analysis strongly suggests that bidnaviruses evolved from a parvovirus ancestor from which they inherit a jelly-roll capsid protein and a superfamily 3 helicase. The radiation of bidnaviruses from parvoviruses was probably triggered by integration of the ancestral parvovirus genome into a large virus-derived DNA transposon of the Polinton (polintovirus) family resulting in the acquisition of the polintovirus PolB gene along with terminal inverted repeats. Bidnavirus genes for a receptor-binding protein and a potential novel antiviral defense modulator are derived from dsRNA viruses (Reoviridae) and dsDNA viruses (Baculoviridae), respectively. The unusual evolutionary history of bidnaviruses emphasizes the key role of horizontal gene transfer, sometimes between viruses with completely different genomes but occupying the same niche, in the emergence of new viral types.

Selectin catch-bonds mechanotransduce integrin activation and neutrophil arrest on inflamed endothelium under shear flow.

PubMed

Morikis, Vasilios A; Chase, Shannon; Wun, Ted; Chaikof, Elliot L; Magnani, John L; Simon, Scott I

2017-11-09

E-selectin extends from the plasma membrane of inflamed endothelium and serves to capture leukocytes from flowing blood via long-lived catch-bonds that support slow leukocyte rolling under shear stress. Its ligands are glycosylated with the tetrasaccharide sialyl Lewis x (sLe x ), which contributes to bond affinity and specificity. E-selectin-mediated rolling transmits signals into neutrophils that trigger activation of high-affinity β 2 -integrins necessary for transition to shear-resistant adhesion and transendothelial migration. Rivipansel is a glycomimetic drug that inhibits E-selectin-mediated vaso-occlusion induced by integrin-dependent sickle-red blood cell-leukocyte adhesion. How Rivipansel antagonizes ligand recognition by E-selectin and blocks outside-in signaling of integrin-mediated neutrophil arrest while maintaining rolling immune-surveillance is unknown. Here, we demonstrate that sLe x expressed on human L-selectin is preferentially bound by E-selectin and, on ligation, initiates secretion of MRP8/14 that binds TLR4 to elicit the extension of β 2 -integrin to an intermediate affinity state. Neutrophil rolling over E-selectin at precise shear stress transmits tension and catch-bond formation with L-selectin via sLe x , resulting in focal clusters that deliver a distinct signal to upshift β 2 -integrins to a high-affinity state. Rivipansel effectively blocked formation of selectin catch-bonds, revealing a novel mechanotransduction circuit that rapidly converts extended β 2 -integrins to high-affinity shear-resistant bond clusters with intracellular adhesion molecule 1 on inflamed endothelium.

Resistance to High-Temperature Oxidation and Wear of Various Ferrous Alloys Used in Rolling Mills

NASA Astrophysics Data System (ADS)

Delaunois, Fabienne; Stanciu, Victor Ioan; Sinnaeve, Mario

2018-03-01

Various materials are commonly used to manufacture work rolls for hot rolling mills, such as ICDP (Indefinite Chill Double Pour) cast irons, high-chromium white cast irons, and high speed steels (HSS). Various chemical compositions and microstructures are studied in order to optimize the in-use behavior of those grades of rolls. In this paper, six grades of ferrous alloys (an ICDP cast iron; an ICDP cast iron enriched in vanadium, niobium, and molybdenum; a HSS; a graphitic HSS; a high-chromium white cast iron (Hi-Cr); and a niobium-molybdenum-doped high-chromium white cast iron) were investigated. High-temperature oxidation tests with gravimetric means at 575 °C in water vapor atmosphere and sliding wear tests were carried out. The oxidation kinetics was followed during oxidation test. The microstructure was observed by optical and scanning electron microscopies. The oxides formed on the surface of the samples were analyzed by XRD and EDS. The thickness of the oxide scales and the mass gain were measured after oxidation test. The results showed that the behavior of all the grades differed. The oxide scale of HSS and HSS-G grades was fine and their friction coefficient was low. The weight gain after oxidation test of HSS was high. Hi-Cr and M-Hi-Cr grades presented highly porous oxide layer and an important increase of the friction coefficient during wear test. ICDP and M-ICDP had intermediate behavior.

Programming a topologically constrained DNA nanostructure into a sensor

NASA Astrophysics Data System (ADS)

Liu, Meng; Zhang, Qiang; Li, Zhongping; Gu, Jimmy; Brennan, John D.; Li, Yingfu

2016-06-01

Many rationally engineered DNA nanostructures use mechanically interlocked topologies to connect individual DNA components, and their physical connectivity is achieved through the formation of a strong linking duplex. The existence of such a structural element also poses a significant topological constraint on functions of component rings. Herein, we hypothesize and confirm that DNA catenanes with a strong linking duplex prevent component rings from acting as the template for rolling circle amplification (RCA). However, by using an RNA-containing DNA [2] catenane with a strong linking duplex, we show that a stimuli-responsive RNA-cleaving DNAzyme can linearize one component ring, and thus enable RCA, producing an ultra-sensitive biosensing system. As an example, a DNA catenane biosensor is engineered to detect the model bacterial pathogen Escherichia coli through binding of a secreted protein, with a detection limit of 10 cells ml-1, thus establishing a new platform for further applications of mechanically interlocked DNA nanostructures.

Protein Detection via Direct Enzymatic Amplification of Short DNA Aptamers

PubMed Central

Fischer, Nicholas O.; Tarasow, Theodore M.; Tok, Jeffrey B.-H.

2008-01-01

Aptamers are single-stranded nucleic acids that fold into defined tertiary structures to bind target molecules with high specificities and affinities. DNA aptamers have garnered much interest as recognition elements for biodetection and diagnostic applications due to their small size, ease of discovery and synthesis, and chemical and thermal stability. Herein, we describe the design and application of a short DNA molecule capable of both protein target binding and amplifiable bioreadout processes. As both recognition and readout capabilities are incorporated into a single DNA molecule, tedious conjugation procedures required for protein-DNA hybrids can be omitted. The DNA aptamer is designed to be amplified directly by either the polymerase chain reaction (PCR) or rolling circle amplification (RCA) processes, taking advantage of real-time amplification monitoring techniques for target detection. A combination of both RCA and PCR provides a wide protein target dynamic range (1 μM to 10 pM). PMID:17980857

Car suspension system monitoring under road conditions

NASA Astrophysics Data System (ADS)

Fedotov, A. I.; Kuznetsov, N. Y.; Lysenko, A. V.; Vlasov, V. G.

2017-12-01

The paper describes an advanced gyro-based measuring system comprising a CGV-4K central vertical gyro and a G-3M gyrocompass. The advanced system provides additional functions that help measure unsprung mass rotation angles about a vertical axis, rolling angles, trim angles and movements of the unsprung masses of the front (ap and al) and rear b axes when a car wheel hits a single obstruction. The paper also describes the operation of the system, which measures movements of unsprung masses about the body of a car when it hits a single obstruction. The paper presents the dependency diagrams ap = f(t) and al = f(t) for front and rear wheels respectively, as well as b = f(t) for a rear left wheel, which were determined experimentally. Test results for a car equipped with an advanced gyro-based measuring system moving around a circle can form a basis for developing a mathematical model of the process.

Rapid Detection and Identification of a Pathogen's DNA Using Phi29 DNA Polymerase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Y.; Dunn, J.; Gao, S.

2008-10-31

Zoonotic pathogens including those transmitted by insect vectors are some of the most deadly of all infectious diseases known to mankind. A number of these agents have been further weaponized and are widely recognized as being potentially significant biothreat agents. We describe a novel method based on multiply-primed rolling circle in vitro amplification for profiling genomic DNAs to permit rapid, cultivation-free differential detection and identification of circular plasmids in infectious agents. Using Phi29 DNA polymerase and a two-step priming reaction we could reproducibly detect and characterize by DNA sequencing circular DNA from Borrelia burgdorferi B31 in DNA samples containing asmore » little as 25 pg of Borrelia DNA amongst a vast excess of human DNA. This simple technology can ultimately be adapted as a sensitive method to detect specific DNA from both known and unknown pathogens in a wide variety of complex environments.« less

RNA-primed complementary-sense DNA synthesis of the geminivirus African cassava mosaic virus.

PubMed Central

Saunders, K; Lucy, A; Stanley, J

1992-01-01

The plant DNA virus African cassava mosaic virus (ACMV) is believed to replicate by a rolling circle mechanism. To investigate complementary-sense DNA (lagging strand) synthesis, we have analysed the heterogenous form of complementary-sense DNA (H3 DNA) from infected Nicotiana benthamiana by two-dimensional agarose gel electrophoresis and blot hybridisation. The presence of an RNA moeity is demonstrated by comparison of results for nucleic acids resolved on neutral/alkaline and neutral/formamide gels, suggesting that complementary-sense DNA synthesis on the virus-sense single-stranded DNA template is preceded by the synthesis of an RNA primer. Hybridisation with probes to specific parts of ACMV DNA A genome indicates that synthesis of the putative RNA primer initiates between nucleotides 2581-221, a region that includes intergenic sequences that have been implicated in geminivirus DNA replication and the control of gene expression. Images PMID:1475192

Enzymatic production of 'monoclonal stoichiometric' single-stranded DNA oligonucleotides.

PubMed

Ducani, Cosimo; Kaul, Corinna; Moche, Martin; Shih, William M; Högberg, Björn

2013-07-01

Single-stranded oligonucleotides are important as research tools, as diagnostic probes, in gene therapy and in DNA nanotechnology. Oligonucleotides are typically produced via solid-phase synthesis, using polymer chemistries that are limited relative to what biological systems produce. The number of errors in synthetic DNA increases with oligonucleotide length, and the resulting diversity of sequences can be a problem. Here we present the 'monoclonal stoichiometric' (MOSIC) method for enzyme-mediated production of DNA oligonucleotides. We amplified oligonucleotides from clonal templates derived from single bacterial colonies and then digested cutter hairpins in the products, which released pools of oligonucleotides with precisely controlled relative stoichiometric ratios. We prepared 14-378-nucleotide MOSIC oligonucleotides either by in vitro rolling-circle amplification or by amplification of phagemid DNA in Escherichia coli. Analyses of the formation of a DNA crystal and folding of DNA nanostructures confirmed the scalability, purity and stoichiometry of the produced oligonucleotides.

Enzymatic Production of Monoclonal Stoichiometric Single-Stranded DNA Oligonucleotides

PubMed Central

Ducani, Cosimo; Kaul, Corinna; Moche, Martin; Shih, William M.; Högberg, Björn

2013-01-01

Single-stranded oligonucleotides are important as research tools as probes for diagnostics and gene therapy. Today, production of oligonucleotides is done via solid-phase synthesis. However, the capabilities of current polymer chemistry are limited in comparison to what can be produced in biological systems. The errors in synthetic DNA increases with oligonucleotide length, and sequence diversity can often be a problem. Here, we present the Monoclonal Stoichiometric (MOSIC) method for enzymatic DNA oligonucleotide production. Using this method, we amplify oligonucleotides from clonal templates followed by digestion of a cutter-hairpin, resulting in pools of monoclonal oligonucleotides with precisely controlled relative stoichiometric ratios. We present data where MOSIC oligonucleotides, 14–378 nt long, were prepared either by in vitro rolling-circle amplification, or by amplification in Escherichia coli in the form of phagemid DNA. The formation of a DNA crystal and folding of DNA nanostructures confirmed the scalability, purity and stoichiometry of the produced oligonucleotides. PMID:23727986

Programming a topologically constrained DNA nanostructure into a sensor

PubMed Central

Liu, Meng; Zhang, Qiang; Li, Zhongping; Gu, Jimmy; Brennan, John D.; Li, Yingfu

2016-01-01

Many rationally engineered DNA nanostructures use mechanically interlocked topologies to connect individual DNA components, and their physical connectivity is achieved through the formation of a strong linking duplex. The existence of such a structural element also poses a significant topological constraint on functions of component rings. Herein, we hypothesize and confirm that DNA catenanes with a strong linking duplex prevent component rings from acting as the template for rolling circle amplification (RCA). However, by using an RNA-containing DNA [2] catenane with a strong linking duplex, we show that a stimuli-responsive RNA-cleaving DNAzyme can linearize one component ring, and thus enable RCA, producing an ultra-sensitive biosensing system. As an example, a DNA catenane biosensor is engineered to detect the model bacterial pathogen Escherichia coli through binding of a secreted protein, with a detection limit of 10 cells ml−1, thus establishing a new platform for further applications of mechanically interlocked DNA nanostructures. PMID:27337657

Preparation and biomedical applications of programmable and multifunctional DNA nanoflowers

PubMed Central

Lv, Yifan; Hu, Rong; Zhu, Guizhi; Zhang, Xiaobing; Mei, Lei; Liu, Qiaoling; Qiu, Liping; Wu, Cuichen; Tan, Weihong

2016-01-01

We describe a comprehensive protocol for the preparation of multifunctional DNA nanostructures termed nanoflowers (NFs), which are self-assembled from long DNA building blocks generated via rolling-circle replication (RCR) of a designed template. NF assembly is driven by liquid crystallization and dense packaging of building blocks, which eliminates the need for conventional Watson-Crick base pairing. As a result of dense DNA packaging, NFs are resistant to nuclease degradation, denaturation or dissociation at extremely low concentrations. By manually changing the template sequence, many different functional moieties including aptamers, bioimaging agents and drug-loading sites could be easily integrated into NF particles, making NFs ideal candidates for a variety of applications in biomedicine. In this protocol, the preparation of multifunctional DNA NFs with highly tunable sizes is described for applications in cell targeting, intracellular imaging and drug delivery. Preparation and characterization of functional DNA NFs takes ~5 d; the following biomedical applications take ~10 d. PMID:26357007

Scalable amplification of strand subsets from chip-synthesized oligonucleotide libraries

PubMed Central

Schmidt, Thorsten L.; Beliveau, Brian J.; Uca, Yavuz O.; Theilmann, Mark; Da Cruz, Felipe; Wu, Chao-Ting; Shih, William M.

2015-01-01

Synthetic oligonucleotides are the main cost factor for studies in DNA nanotechnology, genetics and synthetic biology, which all require thousands of these at high quality. Inexpensive chip-synthesized oligonucleotide libraries can contain hundreds of thousands of distinct sequences, however only at sub-femtomole quantities per strand. Here we present a selective oligonucleotide amplification method, based on three rounds of rolling-circle amplification, that produces nanomole amounts of single-stranded oligonucleotides per millilitre reaction. In a multistep one-pot procedure, subsets of hundreds or thousands of single-stranded DNAs with different lengths can selectively be amplified and purified together. These oligonucleotides are used to fold several DNA nanostructures and as primary fluorescence in situ hybridization probes. The amplification cost is lower than other reported methods (typically around US$ 20 per nanomole total oligonucleotides produced) and is dominated by the use of commercial enzymes. PMID:26567534

Ferrocenemonocarboxylic-HRP@Pt nanoparticles labeled RCA for multiple amplification of electro-immunosensing.

PubMed

Su, Huilan; Yuan, Ruo; Chai, Yaqin; Mao, Li; Zhuo, Ying

2011-07-15

A multiple amplification immunoassay was proposed to detect alpha-fetoprotein (AFP), which was based on ferrocenemonocarboxylic-HRP conjugated on Pt nanoparticles as labels for rolling circle amplification (RCA). Firstly, the capture antibody (anti-AFP) was immobilized on glass carbon electrode (GCE) deposited nano-sized gold particles. After a typical immuno-sandwich protocol, primary DNA was immobilized by labeling secondary antibody, which acted as a precursor to initiate RCA. The products of RCA provide large amount of sites to link detection DNAs, which were labeled by signal probes (ferrocenemonocarboxylic) and horseradish peroxidase (HRP). Moreover, the enzymatic amplification signals could be produced by the catalysis of HRP and Pt nanoparticles with the addition of H₂O₂. These lead to multiple amplification signals monitoring by electrochemical instrument and further resulted in high sensitivity of the immunoassay with the detection limit of 1.7 pg/mL. Copyright © 2011 Elsevier B.V. All rights reserved.

A study of the nonlinear aerodynamics of bodies in nonplanar motion. Ph.D. Thesis - Stanford Univ., Calif.; [numerical analysis of aerodynamic force and moment systems during large amplitude, arbitrary motions

NASA Technical Reports Server (NTRS)

Schiff, L. B.

1974-01-01

Concepts from the theory of functionals are used to develop nonlinear formulations of the aerodynamic force and moment systems acting on bodies in large-amplitude, arbitrary motions. The analysis, which proceeds formally once the functional dependence of the aerodynamic reactions upon the motion variables is established, ensures the inclusion, within the resulting formulation, of pertinent aerodynamic terms that normally are excluded in the classical treatment. Applied to the large-amplitude, slowly varying, nonplanar motion of a body, the formulation suggests that the aerodynamic moment can be compounded of the moments acting on the body in four basic motions: steady angle of attack, pitch oscillations, either roll or yaw oscillations, and coning motion. Coning, where the nose of the body describes a circle around the velocity vector, characterizes the nonplanar nature of the general motion.

Magnetic nanobeads present during enzymatic amplification and labeling for a simplified DNA detection protocol based on AC susceptometry

NASA Astrophysics Data System (ADS)

Bejhed, Rebecca S.; Strømme, Maria; Svedlindh, Peter; Ahlford, Annika; Strömberg, Mattias

2015-12-01

Magnetic biosensors are promising candidates for low-cost point-of-care biodiagnostic devices. For optimal efficiency it is crucial to minimize the time and complexity of the assay protocol including target recognition, amplification, labeling and read-out. In this work, possibilities for protocol simplifications for a DNA biodetection principle relying on hybridization of magnetic nanobeads to rolling circle amplification (RCA) products are investigated. The target DNA is recognized through a padlock ligation assay resulting in DNA circles serving as templates for the RCA process. It is found that beads can be present during amplification without noticeably interfering with the enzyme used for RCA (phi29 polymerase). As a result, the bead-coil hybridization can be performed immediately after amplification in a one-step manner at elevated temperature within a few minutes prior to read-out in an AC susceptometer setup, i.e. a combined protocol approach. Moreover, by recording the phase angle ξ = arctan(χ″/χ'), where χ and χ″ are the in-phase and out-of-phase components of the AC susceptibility, respectively, at one single frequency the total assay time for the optimized combined protocol would be no more than 1.5 hours, often a relevant time frame for diagnosis of cancer and infectious disease. Also, applying the phase angle method normalization of AC susceptibility data is not needed. These findings are useful for the development of point-of-care biodiagnostic devices relying on bead-coil binding and magnetic AC susceptometry.

Computational Study of the Effect of Slot Orientation on Synthetic Jet-Based Separation Control

DTIC Science & Technology

2012-01-01

Wind Turbine Blades,” Journal of Wind Energy, Vol. 13, Issue 2-3, 2009, pp. 221 – 237. [10] Crook, A. and Wood, N. J., “Measurements and...by these hairpin structures could be desirable for separation control. Roll-up of jets into vortex ring followed by tilting and stretching occurred...at an intermediate Reynolds number and velocity ratio. By increasing these two flow parameters, rapid penetration of the tilted vortex ring up to the

100 M.a. remagnetization as a dating tool for deformation and cleavage in the Central High Atlas (Morocco)

NASA Astrophysics Data System (ADS)

Calvin, P.; Casas, A. M.; Villalain, J. J.; Moussaid, B.

2015-12-01

The High Atlas is an intracontinental chain developed as a result of the inversion of Mesozoic basins during the Cenozoic. Its structure is characterized by ENE-WSW tight anticlines limited by wide synclines. In the central sector of the chain, a pervasive tectonic foliation affects Jurassic limestones and marls. There is a controversy about the age of this tectonic foliation and its relationship with either a Late Jurassic or Cenozoic compressional events. The Jurassic carbonates of the Central High Atlas (CHA) show a widespread syntectonic remagnetization carried by magnetite and dated at 100 M.a. by comparing the paleomagnetic direction obtained by small circle intersection (SCI) method with the apparent polar wander path in NW Africa coordinates. Once the 100 M.a. paleomagnetic direction is known, the obtained paleomagnetic direction remagnetization in each site can be used to restore the bedding at the time of the acquisition. In each site, the in situ mean direction of remagnetization defines a small circle (SC) in a complete rotation about the strike of the bedding. This SC gives all possible original directions of the magnetization and if all deformation events are coaxial and without vertical rotation (as it is the case in the study area) all the SC contains the 100 M.a. expected direction. Then, the angle between the 100 M.a. and the in situ paleomagnetic direction along the small circle, equals the angle of rotation of each bed to ultimately find their dips (paleodip) at 100 M.a. Since the consistency between folding and cleavage can be examined from their geometrical relationship, and bedding can be restored to its 100 M.a. geometry (paleodips obtained from paleomagnetic analysis), two end-members exist for the different examined folds: (i) cleavage is consistent with present-day bedding orientation and attitude of bedding was acquired after remagnetization (Cenozoic cleavage), (ii) cleavage is consistent with bedding, but dip of bedding was acquired during the pre-remagnetization stage, as inferred from paleomagnetic analysis (Mesozoic cleavage). Intermediate possibilities, having cleavage developed during one of the two stages with intermediate dips between present-day orientation and the horizontal, are also possible, and are analyzed in different examples of the Atlas chain.

INDICATIONS OF INTERMEDIATE-SCALE ANISOTROPY OF COSMIC RAYS WITH ENERGY GREATER THAN 57 EeV IN THE NORTHERN SKY MEASURED WITH THE SURFACE DETECTOR OF THE TELESCOPE ARRAY EXPERIMENT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abbasi, R. U.; Abu-Zayyad, T.; Allen, M.

2014-08-01

We have searched for intermediate-scale anisotropy in the arrival directions of ultrahigh-energy cosmic rays with energies above 57 EeV in the northern sky using data collected over a 5 yr period by the surface detector of the Telescope Array experiment. We report on a cluster of events that we call the hotspot, found by oversampling using 20° radius circles. The hotspot has a Li-Ma statistical significance of 5.1σ, and is centered at R.A. = 146.°7, decl. = 43.°2. The position of the hotspot is about 19° off of the supergalactic plane. The probability of a cluster of events of 5.1σ significance, appearingmore » by chance in an isotropic cosmic-ray sky, is estimated to be 3.7 × 10{sup –4} (3.4σ)« less

Yield Asymmetry Design of Magnesium Alloys by Integrated Computational Materials Engineering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Dongsheng; Joshi, Vineet V.; Lavender, Curt A.

2013-11-01

Deformation asymmetry of magnesium alloys is an important factor on machine design in automobile industry. Represented by the ratio of compressive yield stress (CYS) against tensile yield stress (TYS), deformation asymmetry is strongly related to microstructure, characterized by texture and grain size. Modified intermediate phi-model, a polycrystalline viscoplasticity model, is used to predict the deformation behavior of magnesium alloys with different grain sizes. Validated with experimental results, integrated computational materials engineering is applied to find out the route in achieving desired asymmetry by thermomechanical processing. In some texture, for example, rolled texture, CYS/TYS is smaller than 1 under different loadingmore » directions. In some texture, for example, extruded texture, asymmetry is large along normal direction. Starting from rolled texture, the asymmetry will increased to close to 1 along rolling direction after compressed to a strain of 0.2. Our model shows that grain refinement increases CYS/TYS. Besides texture control, grain refinement can also optimize the yield asymmetry. After the grain size decreased to a critical value, CYS/TYS reaches to 1 since CYS increases much faster than TYS. By tailoring the microstructure using texture control and grain refinement, it is achievable to optimize yield asymmetry in wrought magnesium alloys.« less

Yield asymmetry design of magnesium alloys by integrated computational materials engineering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Dongsheng; Joshi, Vineet; Lavender, Curt

2013-11-01

Deformation asymmetry of magnesium alloys is an important factor on machine design in the automobile industry. Represented by the ratio of compressive yield stress (CYS) against tensile yield stress (TYS), deformation asymmetry is strongly related to texture and grain size. A polycrystalline viscoplasticity model, modified intermediate Φ-model, is used to predict the deformation behavior of magnesium alloys with different grain sizes. Validated with experimental results, integrated computational materials engineering is applied to find out the route in achieving desired asymmetry via thermomechanical processing. For example, CYS/TYS in rolled texture is smaller than 1 under different loading directions. In other textures,more » such as extruded texture, CYS/TYS is large along the normal direction. Starting from rolled texture, asymmetry will increase to close to 1 along the rolling direction after being compressed to a strain of 0.2. Our modified Φ-model also shows that grain refinement increases CYS/TYS. Along with texture control, grain refinement also can optimize the yield asymmetry. After the grain size decreases to a critical value, CYS/TYS reaches to 1 because CYS increases much faster than TYS. By tailoring the microstructure using texture control and grain refinement, it is achievable to optimize yield asymmetry in wrought magnesium alloys.« less

Electron Microscopic Analysis of the Products of DNA Synthesis by DNA Polymerases from Calf Thymus and Herpes Simplex Virus Type I

DTIC Science & Technology

1988-10-03

DNA replication showed an average of 2.5 primers per M13 DNA circle. The measurement of the double stranded length from individual replicative intermediates by electron microscopy was within the accuracy of 10% standard deviation. The product length distribution obtained from the HSV-1 DNA polymerase catalyzed replication of M13 DNA primed with a specific pentadecamer and in the presence of E. Coli SSB protein showed a near Poisson distribution. Replication of the same primer-template system or DNA primase primed M13 DNA template by calf thymus DNA polymerase a showed a

Fabrication of multifilamentary Nb/sub 3/(Al,Ge) wires through a modified jelly roll process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tachikawa, K.; Kamisada, Y.; Suzuki, E.

Recently, development of Nb/sub 3/Al multifilamentary wires has gained much interests since high-field performance superior to that of Nb/sub 3/Sn can be expected in these wires. In this study, Nb/Al-Ge alloy composites were fabricated into multifilamentary wires through a modified jelly roll (MJR) process. A Nb mesh sheet produced at the Teledyne Wah Chang Co. was used as Nb component. An Al-Ge alloy prepared by a conventional casting process was forged and rolled into a sheet of 0.2 mm in thickness. The Nb/Al-Ge composite was prepared by wrapping the Nb mesh sheet together with the Al-Ge alloy sheet around amore » Nb core into a jelly roll form. The MJR composite was encased in a Cu-Ni alloy tube of which outer diameter was 43 mm. The resulting composite was hydrostatically pressed and extruded into a rod of 18 mm in diameter. A Nb barrier was then inserted between the MJR and the Cu-Ni jacket. The composite rod was swaged and drawn into a wire without any intermediate annealing. The wire was able to be drawn down to a very small diameter of 0.1 mm. The cross-sectional configuration of the MJR composite was not much disturbed by the fabrication. Superconducting transition temperature Tc of the wire, after different heat treatment including a rapid quenching from high temperatures by a continuous electron beam irradiation, was studied, and an onset Tc of 19.3K has been achieved.« less

Recent progress in developing durable and permanent impeller pump.

PubMed

Qian, K X; Zeng, P; Ru, W M; Yuan, H Y

2002-04-01

Since 1980s, the author's impeller pump has successively achieved the device implantability, blood compatibility and flow pulsatility. In order to realize a performance durability, the author has concentrated in past years on solving the bearing problems of the impeller pump. Recent progress has been obtained in developing durable and permanent impeller blood pumps. At first, a durable impeller pump with rolling bearing and purge system has been developed, in which the wear-less rollers made of super-high-molecular weight polythene make the pump to work for years without mechanical wear; and the purge system enables the bearing to work in saline and heparin, and no thrombus therefore could be formed. Secondly, a durable centrifugal pump with rolling bearing and axially reciprocating impeller has been developed, the axial reciprocation of rotating impeller makes the fresh blood in and out of the bearing and to wash the rollers once a circle; in such way, no thrombus could be formed and no fluid infusion is necessary, which may bring inconvenience and discomfort to the receptors. Finally, a permanent maglev impeller pump has been developed, its rotor is suspended and floating in the blood under the action of permanent magnetic force and nonmagnetic forces, without need for position measurement and feed-back control. In conclusion, an implantable, pulsatile, and blood compatible impeller pump with durability may have more extensive applications than ever before and could replace the donor heart for transplantation in the future.

Graphite to ultrafine nanocrystalline diamond phase transition model and growth restriction mechanism induced by nanosecond laser processing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ren, X. D., E-mail: renxd@mail.ujs.edu.cn; Liu, R.; Zheng, L. M.

2015-10-05

To have a clear insight into nanocrystal growth from graphite to diamond upon high energy pulsed laser irradiation of graphite suspension, synthesis of ultrafine nanocrystalline diamonds with laser energy set up from 0.3 J to 12 J, repetition rate of 10 Hz has been studied. The method allows synthesizing ultrafine nanocrystalline particles continuously at the ambient temperature and normal pressure. The particle size is shown independent of laser energy, which is ultrafine and ranges in 2–6 nm. The theoretical grown size of nano-diamonds is found in well agreement with the experiment results. Four kinds of production were found: nano-diamond, spherical carbon nano-particles, flocculent amorphousmore » carbon, and graphene nano-ribbon rolls. A solid-vapor-plasma-liquid coexistence model describing phase transition from graphite to diamond induced by nanosecond laser processing was proposed. Graphene nano-ribbon rolls might be the intermediate phase in the conversion from graphite to diamond.« less

Reynolds Number Effects on the Performance of Ailerons and Spoilers (Invited)

NASA Technical Reports Server (NTRS)

Mineck, R. E.

2001-01-01

The influence of Reynolds number on the performance of outboard spoilers and ailerons was investigated on a generic subsonic transport configuration in the National Transonic Facility over a chord Reynolds number range from 3 to 30 million and a Mach number range from 0.70 to 0.94. Spoiler deflection angles of 0, 10, and 20 degrees and aileron deflection angles of -10, 0, and 10 degrees were tested. Aeroelastic effects were minimized by testing at constant normalized dynamic pressure conditions over intermediate Reynolds number ranges. Results indicated that the increment in rolling moment due to spoiler deflection generally becomes more negative as the Reynolds number increases from 3 x 10(exp 6) to 22 x 10 (exp 6) with only small changes between Reynolds numbers of 22 x 10(exp 6) and 30 x 10(exp 6). The change in the increment in rolling moment coefficient with Reynolds number for the aileron deflected configuration is generally small with a general trend of increasing magnitude with increasing Reynolds number.

Recrystallization texture in nickel heavily deformed by accumulative roll bonding

NASA Astrophysics Data System (ADS)

Mishin, O. V.; Zhang, Y. B.; Godfrey, A.

2017-07-01

The recrystallization behavior of Ni processed by accumulative roll bonding to a total accumulated von Mises strain of 4.8 has been examined, and analyzed with respect to heterogeneity in the deformation microstructure. The regions near the bonding interface are found to be more refined and contain particle deformation zones around fragments of the steel wire brush used to prepare the surface for bonding. Sample-scale gradients are also observed, manifested as differences between the subsurface, intermediate and central layers, where the distributions of texture components are different. These heterogeneities affect the progress of recrystallization. While the subsurface and near-interface regions typically contain lower frequencies of cube-oriented grains than anywhere else in the sample, a strong cube texture forms in the sample during recrystallization, attributed to both a high nucleation rate and fast growth rate of cube-oriented grains. The observations highlight the sensitivity of recrystallization to heterogeneity in the deformation microstructure and demonstrate the importance of characterizing this heterogeneity over several length scales.

Noise Temperature and IF Bandwidth of a 530 GHz Heterodyne Receiver Employing a Diffusion-Cooled Superconducting Hot-Electron Mixer

NASA Technical Reports Server (NTRS)

Skalare, A.; McGrath, W. R.; Bumble, B.; LeDuc, H. G.; Burke, P. J.; Verheijen, A. A.; Prober, D. E.

1995-01-01

We report on the first heterodyne measurements with a diffusion-cooled hot-electron bolometer mixer in the submillimeter wave band, using a waveguide mixer cooled to 2.2 K. The best receiver noise temperature at a local oscillator frequency of 533 GHz and an intermediate frequency of 1.4 GHz was 650 K (double sideband). The 3 dB IF roll-off frequency was around 1.7 to 1.9 GHz, with a weak dependence on the device bias conditions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kan, Jimmy J.; Gottwald, Matthias; Fullerton, Eric E.

We describe low-temperature characterization of magnetic tunnel junctions (MTJs) patterned by reactive ion etching for spin-transfer-torque magnetic random access memory. Magnetotransport measurements of typical MTJs show increasing tunneling magnetoresistance (TMR) and larger coercive fields as temperature is decreased down to 10 K. However, MTJs selected from the high-resistance population of an MTJ array exhibit stable intermediate magnetic states when measured at low temperature and show TMR roll-off below 100 K. These non-ideal low-temperature behaviors arise from edge damage during the etch process and can have negative impacts on thermal stability of the MTJs.

Balancing fast-rotating parts of hand-held machine drive

NASA Astrophysics Data System (ADS)

Korotkov, V. S.; Sicora, E. A.; Nadeina, L. V.; Yongzheng, Wang

2018-03-01

The article considers the issues related to the balancing of fast rotating parts of the hand-held machine drive including a wave transmission with intermediate rolling elements, which is constructed on the basis of the single-phase collector motor with a useful power of 1 kW and a nominal rotation frequency of 15000 rpm. The forms of balancers and their location are chosen. The method of balancing is described. The scheme for determining of residual unbalance in two correction planes is presented. Measurement results are given in tables.

Grain size control of rhenium strip

NASA Technical Reports Server (NTRS)

Schuster, Gary B.

1991-01-01

Ensuring the desired grain size in the pure Re strip employed by the SP-100 space nuclear reactor design entails the establishment of an initial grain size in the as-received strip and the avoidance of excessive grain growth during subsequent fabrication. Pure Re tapered tensile specimens have been fabricated and tested in order to quantify the effects of grain-boundary migration. Grain size could be rendered fine and uniform by means of a rolling procedure that uses rather large reductions between short intermediate anneals. The critical strain regime varies inversely with annealing temperature.

Experiments Testing the Causes of Namibian Fairy Circles.

PubMed

Tschinkel, Walter R

2015-01-01

The grasslands on the sandy soils of the eastern edge of the Namib Desert of Namibia are strikingly punctuated by millions of mostly regularly-spaced circular bare spots 2 to 10 m or more in diameter, generally with a margin of taller grasses. The causes of these so called fairy circles are unknown, but several hypotheses have been advanced. In October 2009, we set up experiments that specifically tested four hypothesized causes, and monitored these 5 times between 2009 and 2015. Grass exclusion in circles due to seepage of subterranean vapors or gases was tested by burying an impermeable barrier beneath fairy circles, but seedling density and growth did not differ from barrier-less controls. Plant germination and growth inhibition by allelochemicals or nutrient deficiencies in fairy circle soils were tested by transferring fairy circle soil to artificially cleared circles in the grassy matrix, and matrix soil to fairy circles (along with circle to circle and matrix to matrix controls). None of the transfers changed the seedling density and growth from the control reference conditions. Limitation of plant growth due to micronutrient depletion within fairy circles was tested by supplementing circles with a micronutrient mixture, but did not result in differences in plant seedling density and growth. Short-range vegetation competitive feedbacks were tested by creating artificially-cleared circles of 2 or 4 m diameter located 2 or 6 m from a natural fairy circle. The natural circles remained bare and the artificial circles revegetated. These four experiments provided evidence that fairy circles were not caused by subterranean vapors, that fairy circle soil per se did not inhibit plant growth, and that the circles were not caused by micronutrient deficiency. There was also no evidence that vegetative feedbacks affected fairy circles on a 2 to 10 m scale. Landscape-scale vegetative self-organization is discussed as a more likely cause of fairy circles.

Enhancement in transport critical current density of ex situ PIT Ag/(Ba, K)Fe2As2 tapes achieved by applying a combined process of flat rolling and uniaxial pressing

NASA Astrophysics Data System (ADS)

Togano, Kazumasa; Gao, Zhaoshun; Matsumoto, Akiyoshi; Kumakura, Hiroaki

2013-11-01

We report that the transport critical current density Jc of ex situ powder-in-tube (PIT) processed (Ba, K)Fe2As2 (Ba-122) tapes can be significantly enhanced by applying uniaxial cold pressing at the final stage of deformation. The tapes were prepared by packing high quality precursor powder into a Ag tube, cycles of rolling and intermediate annealing, and pressing followed by the final heat treatment for sintering. The Jc values in applied magnetic fields were increased by almost one order of magnitude compared to the tapes processed without pressing, exceeding 104 A cm-2 at 4.2 K. We achieved the highest Jc (at 4.2 K and 10 T) of 2.1×104 A cm-2 among PIT-processed Fe-based wires and tapes reported so far. The Jc-H curves measured at higher temperatures maintain small field dependence up to around 20 K, suggesting that these tapes are promising for applications at higher temperatures as well as at liquid helium temperature. The microstructure investigations reveal that there are two possible causes of the large Jc enhancement by pressing: one is densification and the other is the change of crack structure. Optimization of processing parameters such as the reduction ratio of rolling and pressing is expected to yield further Jc enhancement.

Self-assembly Controls Self-cleavage of HHR from ASBVd (-): a Combined SANS and Modeling Study

NASA Astrophysics Data System (ADS)

Leclerc, Fabrice; Zaccai, Giuseppe; Vergne, Jacques; Řìhovà, Martina; Martel, Anne; Maurel, Marie-Christine

2016-07-01

In the Avocado Sunblotch Viroid (ASBVd: 249-nt) from the Avsunviroidae family, a symmetric rolling-circle replication operates through an autocatalytic mechanism mediated by hammerhead ribozymes (HHR) embedded in both polarity strands. The concatenated multimeric ASBVd (+) and ASBVd (-) RNAs thus generated are processed by cleavage to unit-length where ASBVd (-) self-cleaves with more efficiency. Absolute scale small angle neutron scattering (SANS) revealed a temperature-dependent dimer association in both ASBVd (-) and its derived 79-nt HHR (-). A joint thermodynamic analysis of SANS and catalytic data indicates the rate-determining step corresponds to the dimer/monomer transition. 2D and 3D models of monomeric and dimeric HHR (-) suggest that the inter-molecular contacts stabilizing the dimer (between HI and HII domains) compete with the intra-molecular ones stabilizing the active conformation of the full-length HHR required for an efficient self-cleavage. Similar competing intra- and inter-molecular contacts are proposed in ASBVd (-) though with a remoter region from an extension of the HI domain.

Synthesis of a multi-functional DNA nanosphere barcode system for direct cell detection.

PubMed

Han, Sangwoo; Lee, Jae Sung; Lee, Jong Bum

2017-09-28

Nucleic acid-based technologies have been applied to numerous biomedical applications. As a novel material for target detection, DNA has been used to construct a barcode system with a range of structures. This paper reports multi-functionalized DNA nanospheres (DNANSs) by rolling circle amplification (RCA) with several functionalized nucleotides. DNANSs with a barcode system were designed to exhibit fluorescence for coding enhanced signals and contain biotin for more functionalities, including targeting through the biotin-streptavidin (biotin-STA) interaction. Functionalized deoxynucleotide triphosphates (dNTPs) were mixed in the RCA process and functional moieties can be expressed on the DNANSs. The anti-epidermal growth factor receptor antibodies (anti-EGFR Abs) can be conjugated on DNANSs for targeting cancer cells specifically. As a proof of concept, the potential of the multi-functional DNANS barcode was demonstrated by direct cell detection as a simple detection method. The DNANS barcode provides a new route for the simple and rapid selective recognition of cancer cells.

Pilot evaluation of sailplane handling qualities

NASA Technical Reports Server (NTRS)

Bennett, A. G., Jr.

1978-01-01

The evaluation sailplanes were found generally deficient in the area of cockpit layout. The pilots indicated general dissatisfaction with high pitch sensitivity especially when coupled with inertially induced stick forces. While all sailplanes were judged satisfactory for centering thermals and in the ease of speed control in circling flight, pilot opinions diverged on the maneuvering response, pull-out characteristics from a dive, and on phugoid damping. Lateral-directional control problems were noted mainly during takeoff and landing for most sailplanes with the landing wheel ahead of center of gravity. Pilot opinion of in-flight lateral-directional stability and control was generally satisfactory. Five of the evaluation sailplanes exhibited a very narrow airspeed band in which perceptible stall warning buffet occurred. However, this characteristic was considered not objectionable when stall recovery was easy. The pilots objected to the characteristics of a wide airspeed band of stall warning followed by a stall with yawing and rolling tendency and substantial loss of altitude during the stall. Glide path control for the evaluation sailplanes was found to be generally objectionable.

Light-dependent segregation of begomoviruses in Asystasia gangetica leaves.

PubMed

Wyant, Patricia; Strohmeier, Stephan; Fischer, Alexander; Schäfer, Benjamin; Briddon, Rob W; Krenz, Björn; Jeske, Holger

2015-01-02

Asystasia gangetica (Acanthaceae) from tropical Africa and Asia is used as source of food and for medical applications. Plants collected in West Africa in the 1980s with typical geminivirus symptoms showed an unusual symptom segregation that included vein yellowing, curling and mosaic, which were present simultaneously or separately on different leaves of the same plant or on different plants propagated as cuttings from a single plant. Rolling-circle amplification in combination with restriction fragment length polymorphism analysis followed by deep sequencing of the RCA products identified two geminiviruses in these plants. One with a bipartite genome, Asystasia begomovirus 1, and the other with a monopartite genome together with its defective DNA, Asystasia begomovirus 2. The relationship between leaf symptoms and virus distribution under different light regimes was investigated, and showed for the first time an unusual segregation of symptoms and viruses, either within a single plant, or even within a leaf. Copyright © 2014 Elsevier B.V. All rights reserved.

How many papillomavirus species can go undetected in papilloma lesions?

PubMed

Daudt, Cíntia; da Silva, Flavio R C; Streck, André F; Weber, Matheus N; Mayer, Fabiana Q; Cibulski, Samuel P; Canal, Cláudio W

2016-11-03

A co-infection comprising to at least seven papillomavirus (PV) types was detected by next generation sequencing (NGS) of randomly primed rolling circle amplification (RCA) products of a bovine (Bos taurus) papilloma lesion from the Brazilian Amazon region. Six putative new PV types that could not be detected by commonly used PCR protocols were identified. Their overall L1 nucleotide identities were less than 90% compared to described PV species and types. L1 nucleotide BLAST sequence hits showed that each new type was related to Beta, Gamma, Dyokappa, Dyoeta, and Xipapillomavirus, as well as two likely new unclassified genera. Our results show that the employment of NGS is relevant to the detection and characterization of distantly related PV and is of major importance in co-infection studies. This knowledge will help us understand the biology and pathogenesis of PV, as well as contribute to disease control. Moreover, we can also conclude that there are many unknown circulating PVs.

Animal Mitochondrial DNA Replication

PubMed Central

Ciesielski, Grzegorz L.; Oliveira, Marcos T.; Kaguni, Laurie S.

2016-01-01

Recent advances in the field of mitochondrial DNA (mtDNA) replication highlight the diversity of both the mechanisms utilized and the structural and functional organization of the proteins at mtDNA replication fork, despite the simplicity of the animal mtDNA genome. DNA polymerase γ, mtDNA helicase and mitochondrial single-stranded DNA-binding protein- the key replisome proteins, have evolved distinct structural features and biochemical properties. These appear to be correlated with mtDNA genomic features in different metazoan taxa and with their modes of DNA replication, although a substantial integrative research is warranted to establish firmly these links. To date, several modes of mtDNA replication have been described for animals: rolling circle, theta, strand-displacement, and RITOLS/bootlace. Resolution of a continuing controversy relevant to mtDNA replication in mammals/vertebrates will have a direct impact on the mechanistic interpretation of mtDNA-related human diseases. Here we review these subjects, integrating earlier and recent data to provide a perspective on the major challenges for future research. PMID:27241933

Bypass of a Nick by the Replisome of Bacteriophage T7*

PubMed Central

Zhu, Bin; Lee, Seung-Joo; Richardson, Charles C.

2011-01-01

DNA polymerase and DNA helicase are essential components of DNA replication. The helicase unwinds duplex DNA to provide single-stranded templates for DNA synthesis by the DNA polymerase. In bacteriophage T7, movement of either the DNA helicase or the DNA polymerase alone terminates upon encountering a nick in duplex DNA. Using a minicircular DNA, we show that the helicase·polymerase complex can bypass a nick, albeit at reduced efficiency of 7%, on the non-template strand to continue rolling circle DNA synthesis. A gap in the non-template strand cannot be bypassed. The efficiency of bypass synthesis depends on the DNA sequence downstream of the nick. A nick on the template strand cannot be bypassed. Addition of T7 single-stranded DNA-binding protein to the complex stimulates nick bypass 2-fold. We propose that the association of helicase with the polymerase prevents dissociation of the helicase upon encountering a nick, allowing the helicase to continue unwinding of the duplex downstream of the nick. PMID:21701044

Bypass of a nick by the replisome of bacteriophage T7.

PubMed

Zhu, Bin; Lee, Seung-Joo; Richardson, Charles C

2011-08-12

DNA polymerase and DNA helicase are essential components of DNA replication. The helicase unwinds duplex DNA to provide single-stranded templates for DNA synthesis by the DNA polymerase. In bacteriophage T7, movement of either the DNA helicase or the DNA polymerase alone terminates upon encountering a nick in duplex DNA. Using a minicircular DNA, we show that the helicase · polymerase complex can bypass a nick, albeit at reduced efficiency of 7%, on the non-template strand to continue rolling circle DNA synthesis. A gap in the non-template strand cannot be bypassed. The efficiency of bypass synthesis depends on the DNA sequence downstream of the nick. A nick on the template strand cannot be bypassed. Addition of T7 single-stranded DNA-binding protein to the complex stimulates nick bypass 2-fold. We propose that the association of helicase with the polymerase prevents dissociation of the helicase upon encountering a nick, allowing the helicase to continue unwinding of the duplex downstream of the nick.

Exponential isothermal amplification of nucleic acids and amplified assays for proteins, cells, and enzyme activities.

PubMed

Reid, Michael S; Le, X Chris; Zhang, Hongquan

2018-04-27

Isothermal exponential amplification techniques, such as strand-displacement amplification (SDA), rolling circle amplification (RCA), loop-mediated isothermal amplification (LAMP), nucleic acid sequence-based amplification (NASBA), helicase-dependent amplification (HDA), and recombinase polymerase amplification (RPA), have great potential for on-site, point-of-care, and in-situ assay applications. These amplification techniques eliminate the need for temperature cycling required for polymerase chain reaction (PCR) while achieving comparable amplification yield. We highlight here recent advances in exponential amplification reaction (EXPAR) for the detection of nucleic acids, proteins, enzyme activities, cells, and metal ions. We discuss design strategies, enzyme reactions, detection techniques, and key features. Incorporation of fluorescence, colorimetric, chemiluminescence, Raman, and electrochemical approaches enables highly sensitive detection of a variety of targets. Remaining issues, such as undesirable background amplification resulting from non-specific template interactions, must be addressed to further improve isothermal and exponential amplification techniques. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterization of a cryptic plasmid from an alpha-proteobacterial endosymbiont of Amoeba proteus.

PubMed

Park, Miey; Kim, Min-Soo; Lee, Kyung-Min; Hwang, Sue-Yun; Ahn, Tae In

2009-01-01

A new cryptic plasmid pAP3.9 was discovered in symbiotic alpha-proteobacteria present in the cytoplasm of Amoeba proteus. The plasmid is 3869bp with a GC content of 34.66% and contains replication origins for both double-strand (dso) and single-strand (sso). It has three putative ORFs encoding Mob, Rep and phosphoglycolate phosphatase (PGPase). The pAP3.9 plasmid appears to propagate by the conjugative rolling-circle replication (RCR), since it contains all required factors such as Rep, sso and dso. Mob and Rep showed highest similarities to those of the cryptic plasmid pBMYdx in Bacillus mycoides. The PGPase was homologous to that of Bacillus cereus and formed a clade with those of Bacillus sp. in molecular phylogeny. These results imply that the pAP3.9 plasmid evolved by the passage through Bacillus species. We hypothesize that the plasmid-encoded PGPase may have contributed to the establishment of bacterial symbiosis within the hostile environment of amoeba cytoplasm.

The integration of temporally shifted visual feedback in a synchronization task: The role of perceptual stability in a visuo-proprioceptive conflict situation.

PubMed

Ceux, Tanja; Montagne, Gilles; Buekers, Martinus J

2010-12-01

The present study examined whether the beneficial role of coherently grouped visual motion structures for performing complex (interlimb) coordination patterns can be generalized to synchronization behavior in a visuo-proprioceptive conflict situation. To achieve this goal, 17 participants had to synchronize a self-moved circle, representing the arm movement, with a visual target signal corresponding to five temporally shifted visual feedback conditions (0%, 25%, 50%, 75%, and 100% of the target cycle duration) in three synchronization modes (in-phase, anti-phase, and intermediate). The results showed that the perception of a newly generated perceptual Gestalt between the visual feedback of the arm and the target signal facilitated the synchronization performance in the preferred in-phase synchronization mode in contrast to the less stable anti-phase and intermediate mode. Our findings suggest that the complexity of the synchronization mode defines to what extent the visual and/or proprioceptive information source affects the synchronization performance in the present unimanual synchronization task. Copyright © 2010 Elsevier B.V. All rights reserved.

Formation of Millisecond Pulsars with Heavy White Dwarf Companions: Extreme Mass Transfer on Subthermal Timescales.

PubMed

Tauris; van Den Heuvel EP; Savonije

2000-02-20

We have performed detailed numerical calculations of the nonconservative evolution of close X-ray binary systems with intermediate-mass (2.0-6.0 M middle dot in circle) donor stars and a 1.3 M middle dot in circle accreting neutron star. We calculated the thermal response of the donor star to mass loss in order to determine its stability and follow the evolution of the mass transfer. Under the assumption of the "isotropic reemission model," we demonstrate that in many cases it is possible for the binary to prevent a spiral-in and survive a highly super-Eddington mass transfer phase (1

Introducing Nine-Point Circle to Junior High School Students

NASA Astrophysics Data System (ADS)

Fiangga, S.; Azizah, M. A. N.; Rini, R. N. K.; Hidayanti, A. N.

2018-01-01

The concept of circles is an ancient concept that has appeared since Ancient Egypt from which this concept gives many significant contributions in mathematics’ development until now. Nevertheless, the concept of circles hides many uncover mysterious features that are of applications in mathematics. One of the mysterious features is the Nine-Point Circle. This Nine-point circle is also known as Euler’s circle, six-point circle, Feuerbach’s circle, the twelve-point circle, and many others. Because of these different names, there have been misunderstand among mathematicians about the Nine-Point Circle’s history. Besides, the discussion of Nine-Point Circle can be used to be an initial material to explain elementary geometry topic in junior high school’s level curriculum of 2013. Therefore, this concept needs to be delivered to the students as a geometry introduction. A possible form of the integration historical aspect of Nine-point circle is suggested in this paper as well as its importance in the curriculum of 2013.

Assessment of the interns’ ability based on Dundee model in Shiraz University of Medical Sciences

PubMed Central

AMINI, MITRA; ABIRI, SAMANEH; NABEIEI, PARISA; GHANAVATI, SHIRIN; HAYAT, ALI ASGHAR; KOJURI, JAVAD

2015-01-01

Introduction The importance of medical profession and the role of the physician in society is no secret to anyone. Skills and competencies in clinical practice are necessary for the medical profession. In fact, in patient care, doctors require practical skills in addition to scientific knowledge. This study examines the potentials of medical school students in three areas of doing the right thing, doing the right thing in an intermediate range, and doing the right thing by the right person. Methods This study was done in a descriptive-analytical and sectional model. The population of this study was all interns of Shiraz University of Medical Sciences who were passing internship at Internal Medicine, Surgery, Pediatrics, Obstetrics and Emergency wards. About 100 persons were selected by simple randomization. In order to collect data, a questionnaire with 12 questions was designed in two parts. The questionnaire was approved by 7 Faculty members of Clinical Medicine and Medical Education, and its reliability was approved by test-retest method on 20 medical students in the form of a pilot study and through Cronbach's alpha (82%). Collected data were analyzed by SPSS software version 14 using descriptive statistical methods. Results Results showed that within the inner circle, interns evaluated their skills in surgery, internal medicine, and gynecology wards, intermediate and at other wards as weak. Also within the center circle, interns evaluated adequate educational evidence-based training in the field of medicine, and sufficiency of educational training in the field of clinical decision making and clinical care as suitable. Conclusion According to the results, it seems that medical interns' skills in performing most medical skills are moderate. So teaching students by new educational methods and workshop techniques, using experienced teachers will be effective. The use of clinical skills training centers and objective assessment methods for the students' skills, especially before entering the clinical departments, is very important. PMID:26457317

Drusen regression is associated with local changes in fundus autofluorescence in intermediate age-related macular degeneration.

PubMed

Toy, Brian C; Krishnadev, Nupura; Indaram, Maanasa; Cunningham, Denise; Cukras, Catherine A; Chew, Emily Y; Wong, Wai T

2013-09-01

To investigate the association of spontaneous drusen regression in intermediate age-related macular degeneration (AMD) with changes on fundus photography and fundus autofluorescence (FAF) imaging. Prospective observational case series. Fundus images from 58 eyes (in 58 patients) with intermediate AMD and large drusen were assessed over 2 years for areas of drusen regression that exceeded the area of circle C1 (diameter 125 μm; Age-Related Eye Disease Study grading protocol). Manual segmentation and computer-based image analysis were used to detect and delineate areas of drusen regression. Delineated regions were graded as to their appearance on fundus photographs and FAF images, and changes in FAF signal were graded manually and quantitated using automated image analysis. Drusen regression was detected in approximately half of study eyes using manual (48%) and computer-assisted (50%) techniques. At year-2, the clinical appearance of areas of drusen regression on fundus photography was mostly unremarkable, with a majority of eyes (71%) demonstrating no detectable clinical abnormalities, and the remainder (29%) showing minor pigmentary changes. However, drusen regression areas were associated with local changes in FAF that were significantly more prominent than changes on fundus photography. A majority of eyes (64%-66%) demonstrated a predominant decrease in overall FAF signal, while 14%-21% of eyes demonstrated a predominant increase in overall FAF signal. FAF imaging demonstrated that drusen regression in intermediate AMD was often accompanied by changes in local autofluorescence signal. Drusen regression may be associated with concurrent structural and physiologic changes in the outer retina. Published by Elsevier Inc.

The Mediation of Tools in the Development of Formal Mathematical Concepts: The Compass and the Circle as an Example.

ERIC Educational Resources Information Center

Chassapis, Dimitris

1999-01-01

Focuses on the process by which children develop a formal mathematical concept of the circle by using various instruments to draw circles within the context of a goal-directed drawing task. Concludes that the use of the compass in circle drawing structures the circle-drawing operation in a radically different fashion than circle tracers and…

Circling motion and screen edges as an alternative input method for on-screen target manipulation.

PubMed

Ka, Hyun W; Simpson, Richard C

2017-04-01

To investigate a new alternative interaction method, called circling interface, for manipulating on-screen objects. To specify a target, the user makes a circling motion around the target. To specify a desired pointing command with the circling interface, each edge of the screen is used. The user selects a command before circling the target. To evaluate the circling interface, we conducted an experiment with 16 participants, comparing the performance on pointing tasks with different combinations of selection method (circling interface, physical mouse and dwelling interface) and input device (normal computer mouse, head pointer and joystick mouse emulator). A circling interface is compatible with many types of pointing devices, not requiring physical activation of mouse buttons, and is more efficient than dwell-clicking. Across all common pointing operations, the circling interface had a tendency to produce faster performance with a head-mounted mouse emulator than with a joystick mouse. The performance accuracy of the circling interface outperformed the dwelling interface. It was demonstrated that the circling interface has the potential as another alternative pointing method for selecting and manipulating objects in a graphical user interface. Implications for Rehabilitation A circling interface will improve clinical practice by providing an alternative pointing method that does not require physically activating mouse buttons and is more efficient than dwell-clicking. The Circling interface can also work with AAC devices.

A localization algorithm of adaptively determining the ROI of the reference circle in image

NASA Astrophysics Data System (ADS)

Xu, Zeen; Zhang, Jun; Zhang, Daimeng; Liu, Xiaomao; Tian, Jinwen

2018-03-01

Aiming at solving the problem of accurately positioning the detection probes underwater, this paper proposed a method based on computer vision which can effectively solve this problem. The theory of this method is that: First, because the shape information of the heat tube is similar to a circle in the image, we can find a circle which physical location is well known in the image, we set this circle as the reference circle. Second, we calculate the pixel offset between the reference circle and the probes in the picture, and adjust the steering gear through the offset. As a result, we can accurately measure the physical distance between the probes and the under test heat tubes, then we can know the precise location of the probes underwater. However, how to choose reference circle in image is a difficult problem. In this paper, we propose an algorithm that can adaptively confirm the area of reference circle. In this area, there will be only one circle, and the circle is the reference circle. The test results show that the accuracy of the algorithm of extracting the reference circle in the whole picture without using ROI (region of interest) of the reference circle is only 58.76% and the proposed algorithm is 95.88%. The experimental results indicate that the proposed algorithm can effectively improve the efficiency of the tubes detection.

Are Namibian “Fairy Circles” the Consequence of Self-Organizing Spatial Vegetation Patterning?

PubMed Central

Cramer, Michael D.; Barger, Nichole N.

2013-01-01

Causes of over-dispersed barren “fairy circles” that are often surrounded by ca. 0.5 m tall peripheral grasses in a matrix of shorter (ca. 0.2 m tall) grasses in Namibian grasslands remain mysterious. It was hypothesized that the fairy circles are the consequence of self-organizing spatial vegetation patterning arising from resource competition and facilitation. We examined the edaphic properties of fairy circles and variation in fairy circle size, density and landscape occupancy (% land surface) with edaphic properties and water availability at a local scale (<50 km) and with climate and vegetation characteristics at a regional scale. Soil moisture in the barren fairy circles declines from the center towards the periphery and is inversely correlated with soil organic carbon, possibly indicating that the peripheral grass roots access soil moisture that persists into the dry season within fairy circles. Fairy circle landscape occupancy is negatively correlated with precipitation and soil [N], consistent with fairy circles being the product of resource-competition. Regional fairy circle presence/absence is highly predictable using an empirical model that includes narrow ranges of vegetation biomass, precipitation and temperature seasonality as predictor variables, indicating that fairy circles are likely a climate-dependent emergent phenomenon. This dependence of fairy circle occurrence on climate explains why fairy circles in some locations may appear and disappear over time. Fairy circles are only over-dispersed at high landscape occupancies, indicating that inter-circle competition may determine their spacing. We conclude that fairy circles are likely to be an emergent arid-grassland phenomenon that forms as a consequence of peripheral grass resource-competition and that the consequent barren circle may provide a resource-reservoir essential for the survival of the larger peripheral grasses and provides a habitat for fossicking fauna. PMID:23976962

Reynolds Number Effects on the Performance of Lateral Control Devices

NASA Technical Reports Server (NTRS)

Mineck, Raymond E.

2000-01-01

The influence of Reynolds number on the performance of outboard spoilers and ailerons was investigated on a generic subsonic transport configuration in the National Transonic Facility over a chord Reynolds number range 41 from 3x10(exp 6) to 30xl0(exp 6) and a Mach number range from 0.50 to 0.94, Spoiler deflection angles of 0, 10, 15, and 20 deg and aileron deflection angles of -10, 0, and 10 deg were tested. Aeroelastic effects were minimized by testing at constant normalized dynamic pressure conditions over intermediate Reynolds number ranges. Results indicated that the increment in rolling moment due to spoiler deflection generally becomes more negative as the Reynolds number increases from 3x10(exp 6) to 22x10(exp 6) with only small changes between Reynolds numbers of 22x10(exp 6) and 30x10(exp 6). The change in the increment in rolling moment coefficient with Reynolds number for the aileron deflected configuration is generally small with a general trend of increasing magnitude with increasing Reynolds number.

Enhancement of ductility and improvement of abnormal Goss grain growth of magnetostrictive Fe-Ga rolled alloys

NASA Astrophysics Data System (ADS)

Li, Ji-heng; Yuan, Chao; Mu, Xing; Bao, Xiao-qian; Gao, Xue-xu

2018-04-01

The influences of initial microstructures on the mechanical properties and the recrystallization texture of magnetostrictive 0.1at% NbC-doped Fe83Ga17 alloys were investigated. The directionally solidified columnar-grained structure substantially enhanced the tensile elongation at intermediate temperatures by suppressing fracture along the transverse boundaries. Compared with tensile elongations of 1.0% at 300°C and 12.0% at 500°C of the hot-forged equiaxed-grained alloys, the columnar-grained alloys exhibited substantially increased tensile elongations of 21.6% at 300°C and 46.6% at 500°C. In the slabs for rolling, the introduction of <001>-oriented columnar grains also promotes the secondary recrystallization of Goss grains in the finally annealed sheets, resulting in an improvement of the saturation magnetostriction. For the columnar-grained specimens, the inhomogeneous microstructure and disadvantage in number and size of Goss grains are improved in the primarily annealed sheets, which is beneficial to the abnormal growth of Goss grains during the final annealing process.

One-Step Printable Perovskite Films Fabricated under Ambient Conditions for Efficient and Reproducible Solar Cells.

PubMed

Jung, Yen-Sook; Hwang, Kyeongil; Heo, Youn-Jung; Kim, Jueng-Eun; Lee, Donmin; Lee, Cheol-Ho; Joh, Han-Ik; Yeo, Jun-Seok; Kim, Dong-Yu

2017-08-23

Despite the potential of roll-to-roll processing for the fabrication of perovskite films, the realization of highly efficient and reproducible perovskite solar cells (PeSCs) through continuous coating techniques and low-temperature processing is still challenging. Here, we demonstrate that efficient and reliable CH 3 NH 3 PbI 3 (MAPbI 3 ) films fabricated by a printing process can be achieved through synergetic effects of binary processing additives, N-cyclohexyl-2-pyrrolidone (CHP) and dimethyl sulfoxide (DMSO). Notably, these perovskite films are deposited from premixed perovskite solutions for facile one-step processing under a room-temperature and ambient atmosphere. The CHP molecules result in the uniform and homogeneous perovskite films even in the one-step slot-die system, which originate from the high boiling point and low vapor pressure of CHP. Meanwhile, the DMSO molecules facilitate the growth of perovskite grains by forming intermediate states with the perovskite precursor molecules. Consequently, fully printed PeSC based on the binary additive system exhibits a high PCE of 12.56% with a high reproducibility.

Age-dependent variations in the directional sensitivity of balance corrections and compensatory arm movements in man

PubMed Central

Allum, J H J; Carpenter, M G; Honegger, F; Adkin, A L; Bloem, B R

2002-01-01

We investigated the effects of ageing on balance corrections induced by sudden stance perturbations in different directions. Effects were examined in biomechanical and electromyographic (EMG) recordings from a total of 36 healthy subjects divided equally into three age groups (20–34, 35–55 and 60–75 years old). Perturbations consisted of six combinations of support-surface roll (laterally) and pitch (forward-backward) each with 7.5 deg amplitude (2 pure pitch, and 4 roll and pitch) delivered randomly. To reduce stimulus predictability further and to investigate scaling effects, perturbations were at either 30 or 60 deg s−1. In the legs, trunk and arms we observed age-related changes in balance corrections. The changes that appeared in the lower leg responses included smaller stretch reflexes in soleus and larger reflexes in tibialis anterior of the elderly compared with the young. For all perturbation directions, onsets of balance correcting responses in these ankle muscles were delayed by 20–30 ms and initially had smaller amplitudes (between 120–220 ms) in the elderly. This reduced early activity was compensated by increased lower leg activity after 240 ms. These EMG changes were paralleled by comparable differences in ankle torque responses, which were initially (after 160 ms) smaller in the elderly, but subsequently greater (after 280 ms). Findings in the middle-aged group were generally intermediate between the young and the elderly groups. Comparable results were obtained for the two different stimulus velocities. Stimulus-induced trunk roll, but not trunk pitch, changed dramatically with increasing age. Young subjects responded with early large roll movements of the trunk in the opposite direction to platform roll. A similarly directed but reduced amplitude of trunk roll was observed in the middle-aged. The elderly had very little initial roll modulation and also had smaller stretch reflexes in paraspinals. Balance-correcting responses (over 120–220 ms) in gluteus medius and paraspinals were equally well tuned to roll in the elderly, as in the young, but were reduced in amplitude. Onset latencies were delayed with age in gluteus medius muscles. Following the onset of trunk and hip balance corrections, trunk roll was in the same direction as support-surface motion for all age groups and resulted in overall trunk roll towards the fall side in the elderly, but not in the young. Protective arm movements also changed with age. Initial arm roll movements were largest in the young, smaller in the middle aged, and smallest in the elderly. Initial arm roll movements were in the same direction as initial trunk motion in the young and middle aged. Thus initial roll arm movements in the elderly were directed oppositely to those in the young. Initial pitch motion of the arms was similar across age groups. Subsequent arm movements were related to the amplitude of deltoid muscle responses which commenced at 100 ms in the young and 20–30 ms later in the elderly. These deltoid muscle responses preceded additional arm roll motion which left the arms directed ‘downhill’ (in the direction of the fall) in the elderly, but ‘uphill’ (to counterbalance motion of the pelvis) in the young. We conclude that increased trunk roll stiffness is a key biomechanical change with age. This interferes with early compensatory trunk movements and leads to trunk displacements in the direction of the impending fall. The reversal of protective arm movements in the elderly may reflect an adaptive strategy to cushion the fall. The uniform delay and amplitude reduction of balance-correcting responses across many segments (legs, hips and arms) suggests a neurally based alteration in processing times and response modulation with age. Interestingly, the elderly compensated for these ‘early abnormalities’ with enlarged later responses in the legs, but no similar adaptation was noted in the arms and trunk. These changes with age provide an insight into possible mechanisms underlying falls in the elderly. PMID:12122159

Procedure for normalization of cDNA libraries

DOEpatents

Bonaldo, Maria DeFatima; Soares, Marcelo Bento

1997-01-01

This invention provides a method to normalize a cDNA library constructed in a vector capable of being converted to single-stranded circles and capable of producing complementary nucleic acid molecules to the single-stranded circles comprising: (a) converting the cDNA library in single-stranded circles; (b) generating complementary nucleic acid molecules to the single-stranded circles; (c) hybridizing the single-stranded circles converted in step (a) with complementary nucleic acid molecules of step (b) to produce partial duplexes to an appropriate Cot; (e) separating the unhybridized single-stranded circles from the hybridized single-stranded circles, thereby generating a normalized cDNA library.

The newest miracle drug: quality circles in hospitals.

PubMed

McKinney, M M

1984-01-01

In recent years, a number of hospitals throughout the United States have been exploring the use of Japanese-style quality circles to reduce their operating expenses, improve productivity, and enhance the quality of work life for hospital employees. This article examines the organizational climate necessary for quality circles, methods used to implement quality circles, and management's role in guiding and responding to circle activities. Ideas for building and maintaining staff support are presented along with a cost/benefit analysis of quality circle programs. The author concludes that quality circles are most successful in hospitals where they are part of a larger organizational development effort. When administrators believe in their employees' ability to contribute to the institution and are willing to invest necessary time and resources in employee education and the measurement of quality circle achievements, quality circles can produce creative solutions to perplexing institutional problems.

A method for the determination of acrylamide in bakery products using ion trap LC-ESI-MS/MS.

PubMed

Claus, Achim; Weisz, Georg M; Kammerer, Dietmar R; Carle, Reinhold; Schieber, Andreas

2005-10-01

Acrylamide levels of bakery products, e. g., bread and bread rolls, are usually below 100 microg/kg , often even below 50 microg/kg. Therefore, usual analytical methods which have an LOQ greater, not dbl equals 25 microg/kg are not sensitive enough for detailed investigations on acrylamide formation within these commodities. An improved method for trace level determination of acrylamide in bakery products was developed using ion trap LC-ESI-MS/MS. Samples were divided into crumbs and crusts to achieve an initial concentration by removing the crumbs since these are devoid of acrylamide. After sample extraction and clean-up using multimode SPE cartridges, further analyte enrichment was accomplished by solid-phase-supported liquid-liquid extraction with ethyl acetate prior to LC-MS/MS analysis. The method was evaluated using bread, bread rolls, alkali-baked bread rolls, and toast. LOQ was calculated from the confidence interval of the calibration curve and found to be 1.7 ng/mL, corresponding to 17 microg/kg of product. When crumbs and crusts were separated, an LOQ of 10.2 microg/kg of bakery product could be obtained. As demonstrated in preliminary comparative analyses, accuracy of the method met the requirements for determination of trace level acrylamide formation in bakery products. Mean recovery was 102.4% (CV 4.5%), intermediate reproducibility revealed a CV of 2.1%, and a repeatability of CV 6.0%.

Origins and evolution of viruses of eukaryotes: The ultimate modularity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koonin, Eugene V., E-mail: koonin@ncbi.nlm.nih.gov; Dolja, Valerian V., E-mail: doljav@science.oregonstate.edu; Krupovic, Mart, E-mail: krupovic@pasteur.fr

2015-05-15

Viruses and other selfish genetic elements are dominant entities in the biosphere, with respect to both physical abundance and genetic diversity. Various selfish elements parasitize on all cellular life forms. The relative abundances of different classes of viruses are dramatically different between prokaryotes and eukaryotes. In prokaryotes, the great majority of viruses possess double-stranded (ds) DNA genomes, with a substantial minority of single-stranded (ss) DNA viruses and only limited presence of RNA viruses. In contrast, in eukaryotes, RNA viruses account for the majority of the virome diversity although ssDNA and dsDNA viruses are common as well. Phylogenomic analysis yields tangiblemore » clues for the origins of major classes of eukaryotic viruses and in particular their likely roots in prokaryotes. Specifically, the ancestral genome of positive-strand RNA viruses of eukaryotes might have been assembled de novo from genes derived from prokaryotic retroelements and bacteria although a primordial origin of this class of viruses cannot be ruled out. Different groups of double-stranded RNA viruses derive either from dsRNA bacteriophages or from positive-strand RNA viruses. The eukaryotic ssDNA viruses apparently evolved via a fusion of genes from prokaryotic rolling circle-replicating plasmids and positive-strand RNA viruses. Different families of eukaryotic dsDNA viruses appear to have originated from specific groups of bacteriophages on at least two independent occasions. Polintons, the largest known eukaryotic transposons, predicted to also form virus particles, most likely, were the evolutionary intermediates between bacterial tectiviruses and several groups of eukaryotic dsDNA viruses including the proposed order “Megavirales” that unites diverse families of large and giant viruses. Strikingly, evolution of all classes of eukaryotic viruses appears to have involved fusion between structural and replicative gene modules derived from different sources along with additional acquisitions of diverse genes. - Highlights: • Eukaryotic virome dramatically differs from the viromes of bacteria and archaea. • Eukaryotic virome is dominated by RNA viruses and retroelements. • All classes of eukaryotic viruses evolved by gene module exchange. • Prokaryotic ancestry is traceable for core gene modules of most eukaryotic viruses. • Evolutionary histories of viruses and transposable elements are tightly linked.« less

Plume-induced roll back subduction around Venus large coronae

NASA Astrophysics Data System (ADS)

Davaille, A.; Smrekar, S. E.; Tomlinson, S. M.

2016-12-01

On Venus, possible subduction trenches are mainly associated with large coronae, eventhough the latter are thought to be produced by hot mantle plumes. The mechanism of assocation between subduction and plume has long remained elusive. However, we recently observe the same association in laboratory experiments on thermal convection in colloidal aqueous dispersions of silica nanoparticles, which deform in the Newtonian regime at low solid particle fraction φp, and transition to strain-rate weakening, plasticity, elasticity, and brittle properties as φp increases. Hence, a dense skin akin to a planetary lithosphere grows on the surface when the system is dried from above. When a hot plume rises under the skin, the latter undergoes a flexural deformation which puts it under tension. Cracks then develop, sometimes using pre-existing weaknesses. Plume material (being more buoyant that the laboratory lithosphere) upwells through the cracks and spreads as a axisymmetric gravity current above the broken denser skin. The latter bends and sinks under the conjugate action of its own weight and the plume gravity current. The brittle character of the top experimental lithosphere forbids it to deform viscously to accomodate the sinking motions. Instead, the plate continues to tear as a sheet of paper would do upon intrusion. Several slabs are therefore produced, associated with trenches localized along partial circles on the plume, and strong roll-back is always observed. Depending on the lithospheric strength, roll-back can continue and triggers a complete resurfacing, or it stops when the plume stops spreading. Scalings derived from the experiments suggest that a weaker lithosphere than that present on Earth today is required for such a convective regime. We identified two candidates on Venus. At Artemis and Quetzelpetlatl Coronae, the radar image observations and subsurface density variations inferred from modeling the gravity and topography agree with the predictions from the laboratory. Evidence for geologically recent volcanism at Quetzelpetlatl further suggests that subduction may be currently active on Venus. However, a more complete appraisal of this mechanism for Venus resurfacing will require a better knowledge of Venus topography and gravity field, such as proposed by the future mission VERITAS.

A Cross-Sectional Study of the Effect of Quality Circles on Twelve Attitudinal Variables.

DTIC Science & Technology

1985-09-01

task of rebuilding its industrial capabilities which had been largely destroyed during the war. Japanese leaders had a goal of making their country an...members, providing support when necessary, and acting as a liaison between the circles and other organizations. The circle leader or supervisor...34" " .-.-- • .- .".-",,-, . -.- -,: ".’-"’ -. -. .,-’,: Top & Middle - Management Steering Committee Supervisors . . . ....- Circle Circle Leaders Facilitator Employees Circle Members Source

Circles of support and accountability: The characteristics of core members in England and Wales.

PubMed

Clarke, Martin; Warwick, Leah; Völlm, Birgit

2017-04-01

Circles of support and accountability, or Circles, use community volunteers to help reintegrate sex offenders at risk of reoffending in the community. The aims of this study are to describe the first 275 male sex offenders ('core members') in England and Wales supported by a Circle and to compare those attending the five largest Circles. As part of their monitoring activity, 10 Circles extracted data from case files, anonymised it and submitted it to Circles UK, the national oversight body. Circles have expanded rapidly with 165 (60%) of Circles commencing in the three years 2011-2013 compared with 110 in the nine years 2002-2010. Most core members were referred from the Probation Service (82%). Circles were provided to men with a range of predicted risks of reoffending - from low (26%) to very high (12%). There were some positive changes between the beginning and end of Circles, such as fewer men being unemployed and more living in their own chosen accommodation. Circles have been used to support the reintegration of a wide range of sex offenders. Given their rapid growth and flexibility, consistent recording standards are required across. These standards should be reviewed periodically to ensure all important fields of change are captured, including frequency of attendance, length per session and quality of engagement in the work. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Three Concentric Circles: Young Chinese English Learners' Perceptions of Purposeful Audiences

ERIC Educational Resources Information Center

Liu, Jack Jinghui

2015-01-01

English learners have more access to communicate with different purposeful audiences across the Three Concentric Circles of English (Kachu, 1985): the Inner Circle, the Outer Circle and the Expanding Circle. However, young language learners' purposeful audience as a focus of communication has not been emphasized as much as other linguistic…

Development of Carbon Dioxide Hermitic Compressor

NASA Astrophysics Data System (ADS)

Imai, Satoshi; Oda, Atsushi; Ebara, Toshiyuki

Because of global environmental problems, the existing refrigerants are to be replaced with natural refrigerants. CO2 is one of the natural refrigerants and environmentally safe, inflammable and non-toxic refrigerant. Therefore high efficiency compressor that can operate with natural refrigerants, especially CO2, needs to be developed. We developed a prototype CO2 hermetic compressor, which is able to use in carbon dioxide refrigerating systems for practical use. The compressor has two rolling pistons, and it leads to low vibrations, low noise. In additions, two-stage compression with two cylinders is adopted, because pressure difference is too large to compress in one stage. And inner pressure of the shell case is intermediate pressure to minimize gas leakage between compressing rooms and inner space of shell case. Intermediate pressure design enabled to make the compressor smaller in size and lighter in weight. As a result, the compressor achieved high efficiency and high reliability by these technology. We plan to study heat pump water heater, cup vending machine and various applications with CO2 compressor.

Procedure for normalization of cDNA libraries

DOEpatents

Bonaldo, M.D.; Soares, M.B.

1997-12-30

This invention provides a method to normalize a cDNA library constructed in a vector capable of being converted to single-stranded circles and capable of producing complementary nucleic acid molecules to the single-stranded circles comprising: (a) converting the cDNA library in single-stranded circles; (b) generating complementary nucleic acid molecules to the single-stranded circles; (c) hybridizing the single-stranded circles converted in step (a) with complementary nucleic acid molecules of step (b) to produce partial duplexes to an appropriate Cot; (e) separating the unhybridized single-stranded circles from the hybridized single-stranded circles, thereby generating a normalized cDNA library. 1 fig.

Modeling of thermomechanical and metallurgical phenomena in steel strip during hot direct rolling and runout table cooling of thin-cast slabs

NASA Astrophysics Data System (ADS)

Muojekwu, Cornelius Anaedu

The present research was directed at adequate prediction of the temperature, deformation behavior (roll force, flow stress, strain and strain rate) and microstructural evolution (recovery, recrystallization, grain growth, austenite and ferrite grain sizes) during rolling in the Compact Strip Production (CSP) process, as well as the final mechanical properties of the hot rolled strips. This was accomplished with the aid of integrated process modeling, involving mathematical simulation, laboratory experiments and industrial campaigns. The study covered two conventional plain carbon steel grades, the A36 (AISI 1018, 0.17C-0.74Mn) and DQSK (AISI 1005, 0.038C-0.3Mn), and a range of plain carbon steel grades (0.06-0.09 C, 0.16-0.9 Mn) produced at HYLSA's CSP mill at Monterrey, Mexico. In the laboratory, compression tests (both single and double-hits) were carried out on the Gleeble 1500 thermomechanical simulator in order to elucidate the effect of coarse austenite grain size on the flow stress and recrystallization behavior of the plain carbon steels. It was found that coarse grain size not only decreased the flow stress at a given strain but also substantially reduced the tendency toward dynamic recrystallization. An increase in grain size from 244 to 1110 mum which is typical of the first stands of a conventional finishing mill and CSP hot-strip mill respectively, resulted in up to a 30 MPa decrease in the flow stress of both A36 and DQSK steel grades at similar operating conditions of temperature, strain and strain rate. In order to validate the model and laboratory results with mill measurements from an operating CSP plant, an industrial trial was carried out at HYLSA's CSP mill in Monterrey, Mexico. During the industrial campaign, intermediate temperature measurements were made, CSP slab and coil samples were acquired, and all measured and recorded mill data and practices were obtained. Comprehensive mathematical modeling of the rolling process was carried out employing finite difference and finite element analysis. The CSP mill measurements were utilized to validate model predictions of temperature, roll force, grain size and mechanical properties. Good agreement was obtained between prediction and measurement in most of the cases. An estimate of the heat extraction from the various mill sub-units was conducted from the validated calculations. It was found that heat loss by radiation accounted for 48-51 percent of the total heat loss, the work rolls accounted for 41-44 percent, the descaling unit accounted for 4-6 percent and the interstand sprays accounted for the remaining 3-4 percent. It was found that the uniform strain model consistently predicts lower temperatures than the target exit temperature for thin gauges due to a low estimate of deformation heat. Model results captured the details of heat transfer, deformation, recrystallization and austenite decomposition in the CSP mill. The effect of various mill parameters were elucidated, and the similarities and differences between conventional cold-charge rolling and CSP rolling were highlighted. (Abstract shortened by UMI.)

Closed Circular Chains

ERIC Educational Resources Information Center

Caglayan, Günhan

2016-01-01

A Steiner chain is defined as the sequence of n circles that are all tangent to two given non-intersecting circles. A closed chain, in particular, is one in which every circle in the sequence is tangent to the previous and next circles of the chain. In a closed Steiner chain the first and the "n"th circles of the chain are also tangent…

The Director Circle of a Central Conic Section

ERIC Educational Resources Information Center

Ayoub, Ayoub B.

2007-01-01

Each ellipse and hyperbola has a circle associated with it called the director circle. In this article, the author derives the equations of the circle for the ellipse and hyperbola through a different approach. Then the author concentrates on the director circle of the central conic given by the general quadratic equation. The content of this…

A randomized controlled study to establish the effect of articulating instruments on performance in single-incision laparoscopic surgery.

PubMed

Corker, Harry P; Singh, Pritam; Sodergren, Mikael H; Balaji, Sathyan; Kwasnicki, Richard M; Darzi, Ara W; Paraskeva, Paraskevas

2015-01-01

In single-incision laparoscopic surgery (SILS), operating through 1 incision presents ergonomic challenges. No consensus exists on whether articulating instruments (ARTs) may help. This study evaluated their effect on simulated SILS, hypothesizing that they would affect performance and workload. Surgeons were randomized to 2 straight instruments (STRs), 1 ART and 1 STR, or 2 ARTs. After baseline testing, 25 repetitions of the Fundamentals of Laparoscopic Surgery (FLS) peg-transfer (PEG) task and 5 repetitions of the short-hand for the FLS pattern-cutting task (CIRCLE) were performed. Primary outcomes were maximum FLS PEG scores, CIRCLE times and errors, and Imperial College Surgical Assessment Device hand motion analysis. National Aeronautics and Space Administration (NASA) Raw Task Load Index (RTLX) questionnaires evaluated a secondary outcome--workload. The trial took place in a simulated operating theater within the Academic Surgical Unit at St Mary's Hospital, London, UK. Eligible surgeons had completed at least 5 laparoscopic cases as a primary operator. Surgeons were stratified by laparoscopic experience into intermediate (less than 25 previous procedures as primary operator) or advanced (25 procedures or more). A total of 21 surgeons were recruited and randomized; 7 of them to each instrument combination group. All surgeons completed PEG, and 5 from each group completed CIRCLE. Groups' baseline PEG scores were similar (p = 0.625). STR-ART achieved higher maximum PEG scores than STR or ART did (median = 236 vs 198 vs 193, respectively, p = 0.002). Fastest CIRCLE times were similar (median = 190s vs 130s vs 186s, p = 0.129) as were minimum errors (median = 1 vs 2 vs 3, p = 0.101). For PEG, Imperial College Surgical Assessment Device demonstrated similar total path lengths (median = 12.3m vs 12.3m vs 16.0m, p = 0.545) and total numbers of movements (median = 89.6 vs 86.4 vs 171, p = 0.080). Groups' NASA Raw Task Load Index scores were similar (p = 0.708). Combining 1 STR and 1 ART improved SILS performance in the PEG task. Therefore, this may be the optimum instrument configuration for use within some clinical SILS applications. Copyright © 2014 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

Dark Circles under Eyes

MedlinePlus

Symptoms Dark circles under eyes By Mayo Clinic Staff Dark circles under your eyes generally implies that the darkening ... eye. Fatigue is the most common cause of dark circles under your eyes. Sometimes, what appear to ...

Study of the surface wave off-great-circle propagation based on dense seismic array: a case study in Northeast China

NASA Astrophysics Data System (ADS)

Chen, H.; Chong, J.

2016-12-01

The traditional surface wave tomography is based on the ray theory, which assumes that surface wave propagates along the great-circle. The great-circle assumption is valid only when the size of the anomaly is larger than the width of the Fresnel zone and the lateral variation is relatively smooth. However, off-great-circle propagation may occur when the surface wave travels across tectonic boundaries with strong heterogeneity and sharp velocity change, e.g., continental margin, mid-ridge and sea trench, resulting in arrival angle anomaly and multi-pathing effect. The off-great-circle propagation may deviate the result of surface wave tomography based on great-circle approximation, so it is of great importance to study the off-great-circle propagation. In this study, we used the teleseismic waveforms from September 2009 to August 2011, recorded by the NECESSArray in Northeast China, to study the off-great-circle propagation of Rayleigh wave by the Beamforming method. Our results show that the off-great-circle effect increases with decreasing period. At the period of 60 s, the off-great-circle effect is relatively weak and the Rayleigh wave propagates approximately along the great-circle. While at the period of 20 s, the off-great-circle effect becomes strong, the arrival angle anomaly measured from some events can be as large as 20º, and obvious multi-pathing effect is also observed. Lateral variations of the arrival angle anomaly and phase velocity have also been found in the study region, which may be correlated with the lithosphere heterogeneity in Northeast China. Our results demonstrate the necessity to study the surface wave off-great-circle propagation. Acknowledgement: This study is financially supported by National Natural Science Foundation of China under Grant No. 41590854.

Investigation of rolling variables on the structure of steel

NASA Astrophysics Data System (ADS)

Ekebuisi, Godwyn O.

The Literature pertaining to the present research has been critically reviewed. Hot deformation of Nb-free and Nb-containing stainless and C-Mn steels has been carried out by: upset-forging, rolling, and plane strain compression testing. Also, some gridded lead alloy and some mild steel containing Type I MnS inclusions as markers have been hot rolled. Subsequently investigations have been made into: barrelling and lubrication in upsetting; distributions of temperature and strain during thermomechanical working; microstructural processes associated with hot deformation of steel and the evolution of microstructures particularly recrystallised gamma-grain size; isothermal transformation of austenite to ferrite; and the mechanisms governing hot deformation of austenite.Barrelling during the hot upsetting of a solid cylinder arises from the combined effects of interface friction and inhomogeneous distribution of temperature. A barrelling factor, B[f], has been defined to quantify the degree of barrelling and hence of inhomogeneity of deformation in an upset-forged cylinder. Employing glass as a lubricant, an optimised lubrication technique, which ensures homogeneous deformation in upsetting, has been developed and a mechanism of lubrication proposed. The through-thickness temperature distribution of a deforming material, particularly during hot rolling, is inhomogeneous. Generally, the centre-plane temperature rises due to heat generation while the surface-plane temperature drops due to the cooling effects of the tools. Strain distribution during hot rolling is also inhomogeneous. In particular, the vertical strain (epsilon[z]) is minimum at the surface-plane of the material, maximum at the mid-plane and intermediate at the centre-plane.Hot deformation of the stainless steels leads to substructure formation and, at suitably high strains, dynamic and metadynamic recrystallisation. Only a small amount of static recovery precedes static recrystallisation. Nucleation for recrystallisation occurs at preferential sites, particularly serrated boundaries and triple junctions of the deformed prior gamma-grains.The nucleated gamma-grains grow anisotropically and link up to form chains of grains at the prior gamma-grain boundaries. Recrystallisation in hot-rolled samples is inhomogeneous at micro and macro-levels. Particularly, recrystallisation is accelerated at the centre-plane and retarded at the surface plane. This effect arises mainly from non-uniform distribution of temperature and is influenced by material and hot rolling variables. Nb retards recrystallisation by the combined effects of Nb carbide/ nitride particles and Nb atoms in solid solution, the particle effect predominating at 1100°C. Recrystallisation is accelerated by a higher strain, a higher deformation temperature, a higher strain rate, a decrease in the prior ?-grain size, and the presence of deformation bands and twins. A non-isothermal multiple deformation sequence increases the incubation time due to a large temperature drop but promotes a fast recrystallisation rate at the recrystallisation temperature. (Abstract shortened by ProQuest.).

Classification by causes of dark circles and appropriate evaluation method of dark circles.

PubMed

Park, S R; Kim, H J; Park, H K; Kim, J Y; Kim, N S; Byun, K S; Moon, T K; Byun, J W; Moon, J H; Choi, G S

2016-08-01

Dark circles refer to a symptom that present darkness under the eyes. Because of improvement in the quality of life, the dark circles have been recognized as one of major cosmetic concerns. However, it is not easy to classify the dark circles because they have various causes. To select suitable instruments and detailed evaluation items, the dark circles were classified according to the causes through visual assessment, Wood's lamp test, and medical history survey for 100 subjects with dark circles. After the classification, were newly recruited for instrument conformity assessment. Through this, suitable instruments for dark circle evaluation were selected. We performed a randomized clinical trial for dark circles, a placebo-controlled double-blind study, using effective parameters of the instruments selected from the preliminary test. Dark circles of vascular type (35%) and mixed type (54%), a combination of pigmented and vascular types, were the most common. Twenty four subjects with the mixed type dark circles applied the test product (Vitamin C 3%, Vitamin A 0.1%, Vitamin E 0.5%) and placebo on randomized split-face for 8 weeks. The effective parameters (L*, a, M.I., E.I., quasi L*, quasi a* and dermal thickness) were measured during the study period. Result showed that the L* value of Chromameter(®) , Melanin index (M.I.) of Mexameter(®) and quasi L* value obtained by image analysis improved with statistical significance after applying the test product compared with the placebo product. We classified the dark circles according to the causes of the dark circles and verified the reliability of the parameter obtained by the instrument conformity assessment used in this study through the efficacy evaluation. Also based on this study, we were to suggest newly established methods which can be applied to the evaluation of efficacy of functional cosmetics for dark circles. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Cross-correlations between West Texas Intermediate crude oil and the stock markets of the BRIC

NASA Astrophysics Data System (ADS)

Ma, Feng; Wei, Yu; Huang, Dengshi; Zhao, Lin

2013-11-01

In this paper, we investigate the cross-correlation properties between West Texas Intermediate crude oil and the stock markets of the BRIC. We use not only the qualitative analysis of the cross-correlation test, but also take the quantitative analysis of the MF-DXA, confirming the cross-correlation relationship between West Texas Intermediate crude oil and the stock markets of the BRIC (Brazil, Russia, India and China) respectively, which have strongly multifractal features, and the cross-correlations are more strongly multifractal in the short term than in the long term. Furthermore, based on the multifractal spectrum, we also find the multifractality strength between the crude oil WTI and Chinese stock market is stronger than the multifractality strength of other pairs. Based on the Iraq war (Mar 20, 2003) and the Financial crisis in 2008, we divide sample period into four segments to research the degree of the multifractal (ΔH) and the market efficiency (and the risk). Finally, we employ the technique of the rolling window to calculate the time-varying EI (efficiency index) and dependent on the EI, we can easily observe the change of stock markets. Furthermore, we explore the relationship between bivariate cross-correlation exponents (Hxy(q)) and the generalized Hurst exponents.

The effect of pre-straining and pre-ageing on a novel thermomechanical treatment for improving the mechanical properties of AA2139 aerospace aluminium alloys

NASA Astrophysics Data System (ADS)

Bakare, F.; Alsubhi, Y.; Ragkousis, A.; Ebomwonyi, O.; Damisa, J.; Okunzuwa, S.

2017-07-01

The novel thermomechanical treatment employed by Wang Z et al (2014 Mater. Sci. Eng. A 607 313-7) in enhancing the mechanical and microstructure properties of 6000 series aluminium alloys has been replicated for AA2139 aerospace aluminium alloys. The novel route which involves under-ageing, cold-rolling reductions and re-ageing at a fixed temperature has been carried out focusing on the effect of pre-straining and pre-ageing on the alloy properties. The influence of varying cold-rolling reductions and pre-ageing has been examined by tensile testing, hardness testing, differential scanning calorimetry, thermoelectric power measurements and scanning electron microscope (SEM). Further analyses were conducted with DSC and TEP measurements to check for precipitation sequence and solute retention respectively. On comparing the hardness and strength of the non pre-aged to the pre-aged samples, there is a remarkable increase in the hardness and strength of the aerospace alloy showing the huge influence of both pre-ageing and pre-straining stage of the novel thermomechanical treatment as observed in the 6000 series alloy, albeit at a higher rate. The treatments that exhibited the most promising mechanical properties (hardness, yield and ultimate tensile strength, elongation to failure) were found to be at a pre-ageing temperature of 175 °C for 1.5 h, 40% cold-rolling and re-ageing at 150 °C. The material was found to have yield strength of 590 MPa and 8.1% uniform elongation, which is well above the 5% acceptable value for structural applications and with strength levels adaptable for aerospace industries. The presence of higher volume fraction of well dispersed precipitates observed in the SEM further shows that intermediate cold-rolling reductions combines well with pre-ageing to give the best mechanical properties in this alloy.

Structure and Mechanical Properties of Friction Stir Weld Joints of Magnesium Alloy AZ31

NASA Astrophysics Data System (ADS)

Nagasawa, T.; Otsuka, M.; Yokota, T.; Ueki, T.

The applicability of friction stir welding to hot rolled sheet of commercial magnesium alloy AZ31 plates has been investigated. Friction stir weld joint showed mechanical strength comparable to that of base material, though the ductility remained at one half of that of the latter. The results are consistent with the microstructure which is characterized by a fine grained bond layer bounded by-intermediate grained base metals. It is found that both anodizing treatment and insertion of aluminum foil between batting faces do not degrade the joint properties at all. The results suggest that friction stir welding can be potentially applied to magnesium alloy.

Quality circles: Organizational adaptations, improvements and results

NASA Technical Reports Server (NTRS)

Tortorich, R.

1985-01-01

The effective application in industry and government of quality circles work was demonstrated. The results achieved in quality and productivity improvements and cost savings are impressive. The circle process should be institutionalized within industry and government. The stages of circle program growth, innovations that help achieve circle process institutionalization, and the result achieved at Martin Marietta's Michoud Division and within the National Aeronautics and Space Administration (NASA) are addressed.

Participant Experiences of Talking Circles on Type 2 Diabetes in Two Northern Plains American Indian Tribes

PubMed Central

Struthers, Roxanne; Hodge, Felicia Schanche; Geishirt-Cantrell, Betty; De Cora, Lorelei

2011-01-01

The Talking Circle, a culturally appropriate, 12-week educational intervention, was employed on two Northern Plains American Indian reservations to provide information on type 2 diabetes. In a phenomenological study, funded as a minority supplement to the Talking Circle intervention, the authors asked 8 American Indian participants of the Talking Circle to describe their experience of being an American Indian Talking Circle participant. Seven common themes describe the phenomenon of participating in a Talking Circle diabetic intervention. The Talking Circle technique was effective in providing information on type 2 diabetes through culturally appropriate community sharing. Type 2 diabetes is viewed by both outsiders and those involved as a chronic disease of the utmost concern in American Indian communities. PMID:14556421

Direct electrical and mechanical characterization of in situ generated DNA between the tips of silicon nanotweezers (SNT).

PubMed

Karsten, Stanislav L; Kumemura, Momoko; Jalabert, Laurent; Lafitte, Nicolas; Kudo, Lili C; Collard, Dominique; Fujita, Hiroyuki

2016-05-24

Previously, we reported the application of micromachined silicon nanotweezers (SNT) integrated with a comb-drive actuator and capacitive sensors for capturing and mechanical characterization of DNA bundles. Here, we demonstrate direct DNA amplification on such a MEMS structure with subsequent electrical and mechanical characterization of a single stranded DNA (ssDNA) bundle generated between the tips of SNT via isothermal rolling circle amplification (RCA) and dielectrophoresis (DEP). An in situ generated ssDNA bundle was visualized and evaluated via electrical conductivity (I-V) and mechanical frequency response measurements. Colloidal gold nanoparticles significantly enhanced (P < 0.01) the electrical properties of thin ssDNA bundles. The proposed technology allows direct in situ synthesis of DNA with a predefined sequence on the tips of a MEMS sensor device, such as SNT, followed by direct DNA electrical and mechanical characterization. In addition, our data provides a "proof-of-principle" for the feasibility of the on-chip label free DNA detection device that can be used for a variety of biomedical applications focused on sequence specific DNA detection.

Evidence of recombination and positive selection in cetacean papillomaviruses.

PubMed

Robles-Sikisaka, Refugio; Rivera, Rebecca; Nollens, Hendrik H; St Leger, Judy; Durden, Wendy N; Stolen, Megan; Burchell, Jennifer; Wellehan, James F X

2012-06-05

Papillomaviruses (PVs) are small DNA viruses that have been associated with increased epithelial proliferation. Over one hundred PV types have been identified in humans; however, only three have been identified in bottlenose dolphins (Tursiops truncatus) to date. Using rolling circle amplification and degenerate PCR, we identified four novel PV genomes of bottlenose dolphins. TtPV4, TtPV5 and TtPV6 were identified in genital lesions while TtPV7 was identified in normal genital mucosa. Bayesian analysis of the full-length L1 genes found that TtPV4 and TtPV7 group within the Upsilonpapillomavirus genus while TtPV5 and TtPV6 group with Omikronpapillomavirus. However, analysis of the E1 gene did not distinguish these genera, implying that these genes may not share a common history, consistent with recombination. Recombination analyses identified several probable events. Signals of positive selection were found mostly in the E1 and E2 genes. Recombination and diversifying selection pressures constitute important driving forces of cetacean PV evolution. Copyright © 2012 Elsevier Inc. All rights reserved.

[Bioinformatics analysis of mosquito densovirus nostructure protein NS1].

PubMed

Dong, Yun-qiao; Ma, Wen-li; Gu, Jin-bao; Zheng, Wen-ling

2009-12-01

To analyze and predict the structure and function of mosquito densovirus (MDV) nostructual protein1 (NS1). Using different bioinformatics software, the EXPASY pmtparam tool, ClustalX1.83, Bioedit, MEGA3.1, ScanProsite, and Motifscan, respectively to comparatively analyze and predict the physic-chemical parameters, homology, evolutionary relation, secondary structure and main functional motifs of NS1. MDV NS1 protein was a unstable hydrophilic protein and the amino acid sequence was highly conserved which had a relatively closer evolutionary distance with infectious hypodermal and hematopoietic necrosis virus (IHHNV). MDV NS1 has a specific domain of superfamily 3 helicase of small DNA viruses. This domain contains the NTP-binding region with a metal ion-dependent ATPase activity. A virus replication roller rolling-circle replication(RCR) initiation domain was found near the N terminal of this protein. This protien has the biological function of single stranded incision enzyme. The bioinformatics prediction results suggest that MDV NS1 protein plays a key role in viral replication, packaging, and the other stages of viral life.

Acinetobacter phage genome is similar to Sphinx 2.36, the circular DNA copurified with TSE infected particles.

PubMed

Longkumer, Toshisangba; Kamireddy, Swetha; Muthyala, Venkateswar Reddy; Akbarpasha, Shaikh; Pitchika, Gopi Krishna; Kodetham, Gopinath; Ayaluru, Murali; Siddavattam, Dayananda

2013-01-01

While analyzing plasmids of Acinetobacter sp. DS002 we have detected a circular DNA molecule pTS236, which upon further investigation is identified as the genome of a phage. The phage genome has shown sequence similarity to the recently discovered Sphinx 2.36 DNA sequence co-purified with the Transmissible Spongiform Encephalopathy (TSE) particles isolated from infected brain samples collected from diverse geographical regions. As in Sphinx 2.36, the phage genome also codes for three proteins. One of them codes for RepA and is shown to be involved in replication of pTS236 through rolling circle (RC) mode. The other two translationally coupled ORFs, orf106 and orf96, code for coat proteins of the phage. Although an orf96 homologue was not previously reported in Sphinx 2.36, a closer examination of DNA sequence of Sphinx 2.36 revealed its presence downstream of orf106 homologue. TEM images and infection assays revealed existence of phage AbDs1 in Acinetobacter sp. DS002.

Acinetobacter phage genome is similar to Sphinx 2.36, the circular DNA copurified with TSE infected particles

PubMed Central

Longkumer, Toshisangba; Kamireddy, Swetha; Muthyala, Venkateswar Reddy; Akbarpasha, Shaikh; Pitchika, Gopi Krishna; Kodetham, Gopinath; Ayaluru, Murali; Siddavattam, Dayananda

2013-01-01

While analyzing plasmids of Acinetobacter sp. DS002 we have detected a circular DNA molecule pTS236, which upon further investigation is identified as the genome of a phage. The phage genome has shown sequence similarity to the recently discovered Sphinx 2.36 DNA sequence co-purified with the Transmissible Spongiform Encephalopathy (TSE) particles isolated from infected brain samples collected from diverse geographical regions. As in Sphinx 2.36, the phage genome also codes for three proteins. One of them codes for RepA and is shown to be involved in replication of pTS236 through rolling circle (RC) mode. The other two translationally coupled ORFs, orf106 and orf96, code for coat proteins of the phage. Although an orf96 homologue was not previously reported in Sphinx 2.36, a closer examination of DNA sequence of Sphinx 2.36 revealed its presence downstream of orf106 homologue. TEM images and infection assays revealed existence of phage AbDs1 in Acinetobacter sp. DS002. PMID:23867905

Molecular Characterization of Watermelon Chlorotic Stunt Virus (WmCSV) from Palestine

PubMed Central

Ali-Shtayeh, Mohammed S.; Jamous, Rana M.; Mallah, Omar B.; Abu-Zeitoun, Salam Y.

2014-01-01

The incidence of watermelon chlorotic stunt disease and molecular characterization of the Palestinian isolate of Watermelon chlorotic stunt virus (WmCSV-[PAL]) are described in this study. Symptomatic leaf samples obtained from watermelon Citrullus lanatus (Thunb.), and cucumber (Cucumis sativus L.) plants were tested for WmCSV-[PAL] infection by polymerase chain reaction (PCR) and Rolling Circle Amplification (RCA). Disease incidence ranged between 25%–98% in watermelon fields in the studied area, 77% of leaf samples collected from Jenin were found to be mixed infected with WmCSV-[PAL] and SLCV. The full-length DNA-A and DNA-B genomes of WmCSV-[PAL] were amplified and sequenced, and the sequences were deposited in the GenBank. Sequence analysis of virus genomes showed that DNA-A and DNA-B had 97.6%–99.42% and 93.16%–98.26% nucleotide identity with other virus isolates in the region, respectively. Sequence analysis also revealed that the Palestinian isolate of WmCSV shared the highest nucleotide identity with an isolate from Israel suggesting that the virus was introduced to Palestine from Israel. PMID:24956181

Real-space transmission electron microscopy investigations of attachment of functionalized magnetic nanoparticles to DNA-coils acting as a biosensor.

PubMed

Akhtar, Sultan; Strömberg, Mattias; Zardán Gómez de la Torre, Teresa; Russell, Camilla; Gunnarsson, Klas; Nilsson, Mats; Svedlindh, Peter; Strømme, Maria; Leifer, Klaus

2010-10-21

The present work provides the first real-space analysis of nanobead-DNA coil interactions. Immobilization of oligonucleotide-functionalized magnetic nanobeads in rolling circle amplified DNA-coils was studied by complex magnetization measurements and transmission electron microscopy (TEM), and a statistical analysis of the number of beads hybridized to the DNA-coils was performed. The average number of beads per DNA-coil using the results from both methods was found to be around 6 and slightly above 2 for samples with 40 and 130 nm beads, respectively. The TEM analysis supported an earlier hypothesis that 40 nm beads are preferably immobilized in the interior of DNA-coils whereas 130 nm beads, to a larger extent, are immobilized closer to the exterior of the coils. The methodology demonstrated in the present work should open up new possibilities for characterization of interactions of a large variety of functionalized nanoparticles with macromolecules, useful for gaining more fundamental understanding of such interactions as well as for optimizing a number of biosensor applications.

Crosstalk between vertical and horizontal gene transfer: plasmid replication control by a conjugative relaxase

PubMed Central

Lorenzo-Díaz, Fabián; Fernández-López, Cris; Lurz, Rudi

2017-01-01

Abstract Horizontal gene transfer is a key process in the evolution of bacteria and also represents a source of genetic variation in eukaryotes. Among elements participating in gene transfer, thousands of small (<10 kb) mobile bacterial plasmids that replicate by the rolling circle mechanism represent a driving force in the spread of antibiotic resistances. In general, these plasmids are built as genetic modules that encode a replicase, an antibiotic-resistance determinant, and a relaxase that participates in their conjugative mobilization. Further, they control their relatively high copy number (∼30 copies per genome equivalent) by antisense RNAs alone or combined with a repressor protein. We report here that the MobM conjugative relaxase encoded by the promiscuous plasmid pMV158 participates in regulation of the plasmid copy number by transcriptional repression of the antisense RNA, thus increasing the number of plasmid molecules ready to be horizontally transferred (mobilization) and/or vertically inherited (replication). This type of crosstalk between genetic modules involved in vertical and horizontal gene flow has not been reported before. PMID:28525572

SCRaMbLE generates designed combinatorial stochastic diversity in synthetic chromosomes

PubMed Central

Shen, Yue; Stracquadanio, Giovanni; Wang, Yun; Yang, Kun; Mitchell, Leslie A.; Xue, Yaxin; Cai, Yizhi; Chen, Tai; Dymond, Jessica S.; Kang, Kang; Gong, Jianhui; Zeng, Xiaofan; Zhang, Yongfen; Li, Yingrui; Feng, Qiang; Xu, Xun; Wang, Jun; Wang, Jian; Yang, Huanming; Boeke, Jef D.; Bader, Joel S.

2016-01-01

Synthetic chromosome rearrangement and modification by loxP-mediated evolution (SCRaMbLE) generates combinatorial genomic diversity through rearrangements at designed recombinase sites. We applied SCRaMbLE to yeast synthetic chromosome arm synIXR (43 recombinase sites) and then used a computational pipeline to infer or unscramble the sequence of recombinations that created the observed genomes. Deep sequencing of 64 synIXR SCRaMbLE strains revealed 156 deletions, 89 inversions, 94 duplications, and 55 additional complex rearrangements; several duplications are consistent with a double rolling circle mechanism. Every SCRaMbLE strain was unique, validating the capability of SCRaMbLE to explore a diverse space of genomes. Rearrangements occurred exclusively at designed loxPsym sites, with no significant evidence for ectopic rearrangements or mutations involving synthetic regions, the 99% nonsynthetic nuclear genome, or the mitochondrial genome. Deletion frequencies identified genes required for viability or fast growth. Replacement of 3′ UTR by non-UTR sequence had surprisingly little effect on fitness. SCRaMbLE generates genome diversity in designated regions, reveals fitness constraints, and should scale to simultaneous evolution of multiple synthetic chromosomes. PMID:26566658

Rapidly expanding genetic diversity and host range of the Circoviridae viral family and other Rep encoding small circular ssDNA genomes

PubMed Central

Delwart, Eric; Li, Linlin

2011-01-01

The genomes of numerous circoviruses and distantly related circular DNA viruses encoding a rolling circle replication initiator protein (Rep) have been characterized from the tissues of mammals, fish, insects, and plants (geminivirus and nanovirus), human and animal feces, in an algae cell, and in diverse environmental samples. We review the genome organization, phylogenetic relationships and initial prevalence studies of cycloviruses, a proposed new genus in the Circoviridae family. Viral fossil rep sequences were also identified integrated on the chromosomes of mammals, frogs, lancelets, crustaceans, mites, gastropods, roundworms, placozoans, hydrozoans, protozoans, land plants, fungi, algae, and phytoplasma bacterias and their plasmids, reflecting their past host range. An ancient origin for viruses with rep-encoding single stranded small circular genomes, predating the diversification of eukaryotes, is discussed. The cellular hosts and pathogenicity of many recently described rep-containing circular genomes remain to be determined. Future studies of the virome of single cell and multi-cellular eukaryotes are likely to further extend the known diversity and host-range of small rep-containing circular viral genomes. PMID:22155583

Intra- and intermolecular nonenzymatic ligations occur within transcripts derived from the peach latent mosaic viroid.

PubMed

Lafontaine, D; Beaudry, D; Marquis, P; Perreault, J P

1995-10-01

We report here the nonenzymatic self-ligation of transcripts corresponding to the peach latent mosaic viroid (PLMVd). This is the first description of this process with viroid sequences, although it has been reported to occur with human hepatitis delta virus RNA. Self-ligation occurs when the 5'-hydroxyl and the 2',3'-cyclic phosphate termini produced by the hammerhead self-cleavage of the viroid RNA are juxtaposed by the viroid rod-like structure, and a phosphodiester bond is formed between the two following hydrolysis of the cyclic phosphate. Unit-length transcripts undergo intramolecular folding, and their subsequent self-ligation produces circular molecules. The self-ligation observed in vitro may contribute to PLMVd circularization during rolling circle replication; however, this does not exclude the possibility that a host RNA ligase catalyzes the ligation steps in vivo. Like self-cleavage, self-ligation is probably an ancestral reaction, and the enzyme-catalyzed ligation most likely evolved from this primitive mechanism. Furthermore, the intermolecular self-ligation of annealed transcripts derived from PLMVd is demonstrated, suggesting a possible mechanism for sequence reassortment in viroids.

Unusual isothermal multimerization and amplification by the strand-displacing DNA polymerases with reverse transcription activities.

PubMed

Wang, Guoping; Ding, Xiong; Hu, Jiumei; Wu, Wenshuai; Sun, Jingjing; Mu, Ying

2017-10-24

Existing isothermal nucleic acid amplification (INAA) relying on the strand displacement activity of DNA polymerase usually requires at least two primers. However, in this paper, we report an unusual isothermal multimerization and amplification (UIMA) which only needs one primer and is efficiently initiated by the strand-displacing DNA polymerases with reverse transcription activities. On electrophoresis, the products of UIMA present a cascade-shape band and they are confirmed to be multimeric DNAs with repeated target sequences. In contrast to current methods, UIMA is simple to product multimeric DNA, due to the independent of multiple primers and rolling circle structures. Through assaying the synthesized single-stranded DNA targets, UIMA performs high sensitivity and specificity, as well as the universality. In addition, a plausible mechanism of UIMA is proposed, involving short DNA bending, mismatch extension, and template slippage. UIMA is a good explanation for why nonspecific amplification easily happens in existing INAAs. As the simplest INAA till now, UIMA provides a new insight for deeply understanding INAA and opens a new avenue for thoroughly addressing nonspecific amplification.

Evidence of recombination and positive selection in cetacean papillomaviruses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robles-Sikisaka, Refugio, E-mail: refugio.robles1@gmail.com; Rivera, Rebecca, E-mail: RRivera@hswri.org; Nollens, Hendrik H., E-mail: Hendrik.Nollens@SeaWorld.com

2012-06-05

Papillomaviruses (PVs) are small DNA viruses that have been associated with increased epithelial proliferation. Over one hundred PV types have been identified in humans; however, only three have been identified in bottlenose dolphins (Tursiops truncatus) to date. Using rolling circle amplification and degenerate PCR, we identified four novel PV genomes of bottlenose dolphins. TtPV4, TtPV5 and TtPV6 were identified in genital lesions while TtPV7 was identified in normal genital mucosa. Bayesian analysis of the full-length L1 genes found that TtPV4 and TtPV7 group within the Upsilonpapillomavirus genus while TtPV5 and TtPV6 group with Omikronpapillomavirus. However, analysis of the E1 genemore » did not distinguish these genera, implying that these genes may not share a common history, consistent with recombination. Recombination analyses identified several probable events. Signals of positive selection were found mostly in the E1 and E2 genes. Recombination and diversifying selection pressures constitute important driving forces of cetacean PV evolution.« less

KSC-08pd1812

NASA Image and Video Library

2008-06-19

VANDENBERG AIR FORCE BASE, Calif. – The mobile service tower on Space Launch Complex 2 begins to roll back from the Delta II launch vehicle in preparation for launch of the Ocean Surface Topography Mission, or OSTM/Jason 2. The OSTM/Jason 2 satellite will embark on a globe-circling voyage to continue charting sea level, a vital indicator of global climate change. The mission will return a vast amount of new data that will improve weather, climate and ocean forecasts. OSTM/Jason 2's expected lifetime of at least three years will extend into the next decade the continuous record of these data started in 1992 by NASA and the French space agency Centre National d'Etudes Spatiales, or CNES, with the TOPEX/Poseidon mission. The data collection was continued by the two agencies on Jason-1 in 2001. The launch window extends from 12:46 a.m. to 12:55 a.m. PDT. The satellite will be placed in an 830-mile-high orbit at an inclination of 66 degrees after separating from the Delta II 55 minutes after liftoff. Photo credit: Photograph by Carleton Bailie for United Launch Alliance

Advanced DNA-Based Point-of-Care Diagnostic Methods for Plant Diseases Detection.

PubMed

Lau, Han Yih; Botella, Jose R

2017-01-01

Diagnostic technologies for the detection of plant pathogens with point-of-care capability and high multiplexing ability are an essential tool in the fight to reduce the large agricultural production losses caused by plant diseases. The main desirable characteristics for such diagnostic assays are high specificity, sensitivity, reproducibility, quickness, cost efficiency and high-throughput multiplex detection capability. This article describes and discusses various DNA-based point-of care diagnostic methods for applications in plant disease detection. Polymerase chain reaction (PCR) is the most common DNA amplification technology used for detecting various plant and animal pathogens. However, subsequent to PCR based assays, several types of nucleic acid amplification technologies have been developed to achieve higher sensitivity, rapid detection as well as suitable for field applications such as loop-mediated isothermal amplification, helicase-dependent amplification, rolling circle amplification, recombinase polymerase amplification, and molecular inversion probe. The principle behind these technologies has been thoroughly discussed in several review papers; herein we emphasize the application of these technologies to detect plant pathogens by outlining the advantages and disadvantages of each technology in detail.

Advanced DNA-Based Point-of-Care Diagnostic Methods for Plant Diseases Detection

PubMed Central

Lau, Han Yih; Botella, Jose R.

2017-01-01

Diagnostic technologies for the detection of plant pathogens with point-of-care capability and high multiplexing ability are an essential tool in the fight to reduce the large agricultural production losses caused by plant diseases. The main desirable characteristics for such diagnostic assays are high specificity, sensitivity, reproducibility, quickness, cost efficiency and high-throughput multiplex detection capability. This article describes and discusses various DNA-based point-of care diagnostic methods for applications in plant disease detection. Polymerase chain reaction (PCR) is the most common DNA amplification technology used for detecting various plant and animal pathogens. However, subsequent to PCR based assays, several types of nucleic acid amplification technologies have been developed to achieve higher sensitivity, rapid detection as well as suitable for field applications such as loop-mediated isothermal amplification, helicase-dependent amplification, rolling circle amplification, recombinase polymerase amplification, and molecular inversion probe. The principle behind these technologies has been thoroughly discussed in several review papers; herein we emphasize the application of these technologies to detect plant pathogens by outlining the advantages and disadvantages of each technology in detail. PMID:29375588

Made-in-USA Quality Circles Become People-Building Tool.

ERIC Educational Resources Information Center

Cohen, Larry

1983-01-01

Discusses the use of quality circles as a human resources development tool in Middlesex Community College's Career-Oriented Peer Services tutoring center. Delineates rules for circle participants and follows the activities of two circles comprised of business-oriented and engineering-oriented students. (DMM)

Operational improvements at traffic circles : safety analysis, final report, December 2008.

DOT National Transportation Integrated Search

2008-12-01

The purpose of this study was to improve the safety and operation at three traffic circles in New : Jersey. To do this, data were collected at the traffic circles to allow researchers to model the : circles using the PARAMICS software simulation pack...

Structural expression of a rolling hinge in the footwall of the Brenner Line normal fault, eastern Alps

NASA Astrophysics Data System (ADS)

Axen, Gary J.; Bartley, John M.; Selverstone, Jane

1995-12-01

The kinematic and temporal sequence of structures observed to overprint mylonites along the Brenner Line low-angle normal fault may record passage of the footwall through two rolling hinges, at the top and bottom of a ramp in the shear zone. The structures comprise west down brittle and brittle-ductile structures and east down brittle structures. PT conditions of formation (250° to >400°C and 2-23 km depth), obtained from analysis of oriented fluid inclusion planes, indicate that west down structures were formed at greater depths and temperatures, and therefore earlier, than the east down structures. These data suggest that the brittle structures formed under conditions that permit crystal-plastic deformation at long-term geologic strain rates and therefore probably reflect transient rapid strain rates and/or high fluid pressure. Structures inferred to have formed at a lower hinge are consistent with viscous flow models of rolling-hinge deformation and support the concept of a crustal asthenosphere. Such high temperatures at shallow crustal depth also suggest significant upward advection of heat by extensional unroofing of warm rocks, which may have reduced the flexural rigidity of the footwall and thus affected mechanical behavior at the upper rolling hinge. Exposed mylonitic foliation within a few hundred meters of the Brenner line and on top of the east-west trending anticlines in the footwall dips ˜15° west. Our data favor a ramp dip of ˜25° but permit a dip as great as 45°. Fluid inclusion data suggest that structures related to the hinge at the base of the ramp formed at depths of 12-25 km. If the average dip of the Brenner shear zone to those depths was 20°, intermediate between the favored ramp dip and the dip of exposed foliation, then the horizontal component of slip could be as high as 33-63 km. The two discrete sets of structures with opposite shear senses, formed in the temporal sequence indicated by PT data, are consistent with subvertical simple shear models of rolling-hinge strain. This kinematic pattern is not predicted by the flexural-failure model for rolling hinges. However, the predominance of normal slip at the upper hinge, which extends rather than shortens the mylonitic foliation, fails to match the subvertical simple shear model, which predicts shortening of the foliation there. One possible solution is that superposition of regional extension upon hinge-related stresses modified the rolling-hinge kinematics. Such a modified subvertical shear model can account for the observed small foliation-parallel extensional strains if the foliation was bent <5°-10° passing through the upper hinge. If more bending than that occurred, the data suggest rolling-hinge kinematics in which deformation is achieved by uniform-sense simple shear across the shear zone as in the subvertical simple shear model but in which material lines parallel to the shear-zone foliation and the detachment fault undergo very small length changes, presumably indicating that footwall rocks retained significant resistance to shear and underwent minimal permanent strain. The mechanics that would generate such a rolling hinge are uncertain but may incorporate aspects of both subvertical simple shear and flexural failure. An important kinematic consequence of such a rolling hinge is that all of the net slip across a normal fault, not only its horizontal component, is converted into horizontal extension. This implies a significantly larger magnitude of crustal extension across dipping normal faults whose footwalls passed through a rolling hinge than for those that did not develop along with a hinge.

Soil Biota and Litter Decay in High Arctic Ecosystems

NASA Astrophysics Data System (ADS)

González, G.; Rivera, F.; Makarova, O.; Gould, W. A.

2006-12-01

Frost heave action contributes to the formation of non-sorted circles in the High Arctic. Non-sorted circles tend to heave more than the surrounding tundra due to deeper thaw and the formation of ice lenses. Thus, the geomorphology, soils and vegetation on the centers of the patterned-ground feature (non-sorted circles) as compared to the surrounding soils (inter-circles) can be different. We established a decomposition experiment to look at in situ decay rates of the most dominant graminoid species on non-sorted circles and adjacent inter-circle soils along a climatic gradient in the Canadian High Arctic as a component of a larger study looking at the biocomplexity of small-featured patterned ground ecosystems. Additionally, we investigated variation in soil chemical properties and biota, including soil microarthropods and microbial composition and biomass, as they relate to climate, topographic position, and litter decay rates. Our three sites locations, from coldest to warmest, are Isachsen, Ellef Ringnes Island (ER), NU (bioclimatic subzone A); Mould Bay (MB), Prince Patrick Island, NT (bioclimatic subzone B), and Green Cabin (GC), Aulavik National Park, Thomsen River, Banks Island, NT (bioclimatic subzone C). Our sample design included the selection of 15 non-sorted circles and adjacent inter-circle areas within the zonal vegetation at each site (a total of 90 sites), and a second set of 3 non-sorted circles and adjacent inter-circle areas in dry, mesic and wet tundra at each of the sites. Soil invertebrates were sampled at each site using both pitfall traps, soil microbial biomass was determined using substrate induced respiration and bacterial populations were determined using the most probable number method. Decomposition rates were measured using litterbags and as the percent of mass remaining of Carex misandra, Luzula nivalis and Alopecuris alpinus in GC, MB and ER, respectively. Our findings indicate these graminoid species decayed significantly over time at a rate of 10-15 % mass loss / yr during the first year of decay. Decay rates are different in non-sorted circles vs. inter-circle soils along the climatic gradient. In MB, L. nivalis seems to decay faster in the inter-circle soils than in non-sorted circles (0.05

Effect of Starting As-cast Structure on the Microstructure-Texture Evolution During Subsequent Processing and Finally Ridging Behavior of Ferritic Stainless Steel

NASA Astrophysics Data System (ADS)

Modak, Pranabananda; Patra, Sudipta; Mitra, Rahul; Chakrabarti, Debalay

2018-03-01

Effect of the initial as-cast structure on the microstructure-texture evolution during thermomechanical processing of 409L grade ferritic stainless steel was studied. Samples from the regions of cast slab having `columnar,' `equiaxed,' and a mixture of `columnar' and `equiaxed' grains were subjected to two different processing schedules: one with intermediate hot-band annealing before cold-rolling followed by final annealing, and another without any hot-band annealing. EBSD study reveals that large columnar crystals with cube orientation are very difficult to deform and recrystallize uniformly. Resultant variations in ferrite grain structure and retention of cube-textured band in cold-rolled and annealed sheet contribute to ridging behavior during stretch forming. Initial equiaxed grain structure is certainly beneficial to reduce or even eliminate ridging defect by producing uniform ferrite grain structure, free from any texture banding. Application of hot-band annealing treatment is also advantageous as it can maximize the evolution of beneficial gamma-fiber texture and eliminate the ridging defect in case of completely `equiaxed' starting structure. Such treatment reduces the severity of ridging even if the initial structure contains typically mixed `columnar-equiaxed' grains.

Effect of Starting As-cast Structure on the Microstructure-Texture Evolution During Subsequent Processing and Finally Ridging Behavior of Ferritic Stainless Steel

NASA Astrophysics Data System (ADS)

Modak, Pranabananda; Patra, Sudipta; Mitra, Rahul; Chakrabarti, Debalay

2018-06-01

Effect of the initial as-cast structure on the microstructure-texture evolution during thermomechanical processing of 409L grade ferritic stainless steel was studied. Samples from the regions of cast slab having `columnar,' `equiaxed,' and a mixture of `columnar' and `equiaxed' grains were subjected to two different processing schedules: one with intermediate hot-band annealing before cold-rolling followed by final annealing, and another without any hot-band annealing. EBSD study reveals that large columnar crystals with cube orientation are very difficult to deform and recrystallize uniformly. Resultant variations in ferrite grain structure and retention of cube-textured band in cold-rolled and annealed sheet contribute to ridging behavior during stretch forming. Initial equiaxed grain structure is certainly beneficial to reduce or even eliminate ridging defect by producing uniform ferrite grain structure, free from any texture banding. Application of hot-band annealing treatment is also advantageous as it can maximize the evolution of beneficial gamma-fiber texture and eliminate the ridging defect in case of completely `equiaxed' starting structure. Such treatment reduces the severity of ridging even if the initial structure contains typically mixed `columnar-equiaxed' grains.

Granular self-organization by autotuning of friction.

PubMed

Kumar, Deepak; Nitsure, Nitin; Bhattacharya, S; Ghosh, Shankar

2015-09-15

A monolayer of granular spheres in a cylindrical vial, driven continuously by an orbital shaker and subjected to a symmetric confining centrifugal potential, self-organizes to form a distinctively asymmetric structure which occupies only the rear half-space. It is marked by a sharp leading edge at the potential minimum and a curved rear. The area of the structure obeys a power-law scaling with the number of spheres. Imaging shows that the regulation of motion of individual spheres occurs via toggling between two types of motion, namely, rolling and sliding. A low density of weakly frictional rollers congregates near the sharp leading edge whereas a denser rear comprises highly frictional sliders. Experiments further suggest that because the rolling and sliding friction coefficients differ substantially, the spheres acquire a local time-averaged coefficient of friction within a large range of intermediate values in the system. The various sets of spatial and temporal configurations of the rollers and sliders constitute the internal states of the system. Experiments demonstrate and simulations confirm that the global features of the structure are maintained robustly by autotuning of friction through these internal states, providing a previously unidentified route to self-organization of a many-body system.

Single field double inflation and primordial black holes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kannike, K.; Marzola, L.; Raidal, M.

Within the framework of scalar-tensor theories, we study the conditions that allow single field inflation dynamics on small cosmological scales to significantly differ from that of the large scales probed by the observations of cosmic microwave background. The resulting single field double inflation scenario is characterised by two consequent inflation eras, usually separated by a period where the slow-roll approximation fails. At large field values the dynamics of the inflaton is dominated by the interplay between its non-minimal coupling to gravity and the radiative corrections to the inflaton self-coupling. For small field values the potential is, instead, dominated by amore » polynomial that results in a hilltop inflation. Without relying on the slow-roll approximation, which is invalidated by the appearance of the intermediate stage, we propose a concrete model that matches the current measurements of inflationary observables and employs the freedom granted by the framework on small cosmological scales to give rise to a sizeable population of primordial black holes generated by large curvature fluctuations. We find that these features generally require a potential with a local minimum. We show that the associated primordial black hole mass function is only approximately lognormal.« less

Quality/Performance Circles Three Years after Implementation.

ERIC Educational Resources Information Center

Ladwig, Dennis J.

An overview is provided of the development of quality/performance circles at Lakeshore Technical Institute (LTI), Wisconsin, and of the projects undertaken through the quality/performance circle program during its 3-year history. First, background information is provided on the use of quality circles in Japan and the United States, including…

Fostering Classroom Communities through Circling with Teacher Candidates

ERIC Educational Resources Information Center

Bouchard, Karen L.; Hollweck, Trista; Smith, J. David

2016-01-01

Classroom circles have been recognized as a valuable pedagogical approach to develop students' social-emotional learning and to establish a sense of community within a classroom. Until recently, there has been little consideration that teachers, themselves, may benefit from circling experiences. To garner a deeper understanding of circling for…

Making Morning Circle Meaningful

ERIC Educational Resources Information Center

Bruce, Susan; Fasy, Cara; Gulick, Jessica; Jones, Jill; Pike, Elizabeth

2006-01-01

Morning Circle, also known as Morning Meeting, is often a daily lesson in both general education and special education classrooms. The primary purpose of the Circle is to support each child to establish membership in the class while developing a classroom community and culture. The Responsive Classroom Approach recommends four Circle components:…

Transaction Circles with Digital Texts as a Foundation for Democratic Practices

ERIC Educational Resources Information Center

Brown, Sally

2015-01-01

Transaction circles weave together elements of guided reading and literature circles in an open conversational structure that supports students as agentive learners. Discourse within these circles utilizing digital informational texts assist in the development of democratic practices even in a time when federal mandates limit curricula and…

Perceptual Differences in Attitudes on Quality Circles.

ERIC Educational Resources Information Center

Holcomb, Lynn; Berger, Leonard

1986-01-01

A study was conducted to determine any perceptual differences toward quality circles in a chemical plant. It also tried to determine if any perceptual differences that might be found could be related to attitudes toward the circles themselves or the attitudes toward circle members. Length of service was also a factor. (CT)

Quality Circles: Determination of Significant Factors for Success an a General Model for Implementing a Quality Circle Process.

DTIC Science & Technology

1981-06-01

receive for contributions to quality and productivity /4:Apdx-47. The initiative for the Quality Circle concept came from Dr Kaoru Ishikawa , a...eloquently summarized by the "Father of Quality Circles", Dr Kaoru Ishikawa . He sees that, although Japan started with the worst quality reputation among...Perceptions of Influence, Academy of Management Journal. December 1974, pp 649-bz. 49. Ishikawa , Kaoru . S.C. Circle Activities. Union of Japanese Scientists and

GENERATING FRACTAL PATTERNS BY USING p-CIRCLE INVERSION

NASA Astrophysics Data System (ADS)

Ramírez, José L.; Rubiano, Gustavo N.; Zlobec, Borut Jurčič

2015-10-01

In this paper, we introduce the p-circle inversion which generalizes the classical inversion with respect to a circle (p = 2) and the taxicab inversion (p = 1). We study some basic properties and we also show the inversive images of some basic curves. We apply this new transformation to well-known fractals such as Sierpinski triangle, Koch curve, dragon curve, Fibonacci fractal, among others. Then we obtain new fractal patterns. Moreover, we generalize the method called circle inversion fractal be means of the p-circle inversion.

Microstructure, Mechanical Properties, Hot-Die Forming, and Joining of 47XD Gamma TiAl Rolled Sheets

NASA Technical Reports Server (NTRS)

Das, G.; Draper, S.; Whittenberger, J. D.; Bartolotta, P. A.

2001-01-01

The microstructure and mechanical properties, along with the hot-die forming and joining of Ti-47Al-2Nb-2Mn-0.8 vol% TiB, sheets (known as 47XD), produced by a low-cost rolling process, were evaluated. A near-gamma microstructure was obtained in the as-rolled condition. The microstructures of heat-treated sheets ranged from a recrystallized equiaxed near-gamma microstructure at 1,200 to 1,310 C, to a duplex microstructure at 1,350 C, to a fully lamellar microstructure at 1,376 C. Tensile behavior was determined for unidirectionally rolled and cross-rolled sheets for room temperature (RT) to 816 C. Yield stress decreased gradually with increasing deformation temperature up to 704 C; above 704 C, it declined rapidly. Ultimate tensile strength exhibited a gradual decrease up to 537 C before peaking at 704 C, followed by a rapid decline at 816 C. The modulus showed a gradual decrease with temperature, reaching approximately 72% of the RT value at 816 C. Strain to failure increased slowly from RT to 537 C; between 537 C and 704 C it exhibited a phenomenal increase, suggesting that the ductile-brittle transition temperature was below 704 C. Fracture mode changed from transgranular fracture at low temperature, to a mixture of transgranular and intergranular fracture at intermediate temperature, to ductile fracture at 816 C, coupled with dynamic recrystallization at large strains. Creep rupture response was evaluated between 649 and 816 C over the stress range of 69 to 276 MPa. Deformation parameters for steady-state creep rate and time-to-rupture were similar: activation energies of approximately 350 kJ/mol and stress exponents of approximately 4.5. Hot-die forming of sheets into corrugations was done at elevated temperatures in vacuum. The process parameters to join sheets by diffusion bonding and brazing with TiCuNi 70 filler alloy were optimized for test coupons and successfully used to fabricate large truss-core and honeycomb structures. Nondestructive evaluation methods, e.g., ultrasonic C-scans and thermography along with metallography, were used to characterize bond quality. Microstructural evaluation during heat treatment, identification of phases at the braze/matrix interface, determination of shear strengths of brazed joints, and deformation mechanisms during tensile and creep processes will be discussed.

Native American Values and Management Education: Envisioning an Inclusive Virtuous Circle

ERIC Educational Resources Information Center

Verbos, Amy Klemm; Gladstone, Joe S.; Kennedy, Deanna M.

2011-01-01

Circles are symbols of interconnectedness. Behavioral circles can be vicious or virtuous. Many American Indians are caught in a vicious circle of exclusion from the purported benefits of Westernization, entrapment in its negative elements, and the ongoing undermining of their culture and thus their identities. Yet Native Americans, along with many…

The Value of the Math Circle for Gifted Middle School Students

ERIC Educational Resources Information Center

Burns, Barbara; Henry, Julie; McCarthy, Dianne; Tripp, Jennifer

2017-01-01

Math Circles are designed to allow students to explore mathematics using a problem-solving/inquiry approach. Many of the students attending our Math Circle are mathematically talented and curious. This study examines the perspectives of the students and their families in determining why students attend Math Circle, what they enjoy about Math…

Expanding the Reach of Extension to Underserved Audiences through Study Circles in Rural Idaho

ERIC Educational Resources Information Center

Cummins, Melissa; Petty, Barbara; Hansen, Lyle; Hoffman, Katie; Wittman, Grace

2012-01-01

Extension educators expanded the reach of their programming to underserved audiences through the implementation of Study Circles in rural Southern Idaho. Study Circles gave educators entry into communities by establishing relationships necessary for long-term change. Study Circle discussions in rural Southern Idaho led to stronger relationships…

The Acoustic Reality of the Kachruvian Circles: A Rhythmic Perspective

ERIC Educational Resources Information Center

Low, Ee Ling

2010-01-01

This paper investigates whether the rhythmic properties of varieties of English found in each of the concentric circles of Kachru's model can, in any way, be elucidated by the "Three Circles" model. A measurement and comparison of the rhythm of three varieties of English: British English (from the Inner Circle), Singapore English (from…

The Relationship of Communication to Productivity: Quality Circles as a Mediating Variable.

ERIC Educational Resources Information Center

Creagh, Sara; Smeltzer, Larry

Quality circles, small groups of employees working voluntarily toward performance improvement, have become a popular business strategy in the past decade. When effective, the quality circle may be linked directly to the increased productivity of the work group. The quality circle process may be divided into four components: identification and…

Quality Circles: Involvement, Problem-Solving, and Recognition.

ERIC Educational Resources Information Center

Moretz, H. Lynn

1983-01-01

The media production department of Central Piedmont Community College (CPCC) began quality circle meetings in January 1981 after studying the process of quality circles and obtaining the understanding and support of the college administration. A quality circle is a small group of people doing similar work who voluntarily meet on a regular basis to…

The "Us" in Discuss: Grouping in Literature Circles

ERIC Educational Resources Information Center

Batchelor, Katherine

2012-01-01

This article describes one middle school teacher's use of literature circles using heterogeneous grouping. It begins with a brief rationale for using literature circles in the language arts classroom. Next, it describes techniques to form literature circles. Then, it shares how to build and establish a supportive environment within each group. It…

A Round Is a Circle...

ERIC Educational Resources Information Center

Boyarsky, Terry L.

2006-01-01

Circles are everywhere and endlessly intriguing. We know, sense, and feel them in time, space, sound, and the cycles of nature. A person's life contains spirals, repetitions, going out and coming back. Poets write of circles; composers write song cycles. Circles are at the root of the curriculum, concepts deep yet accessible, infinite in their…

Accuracy of tree diameter estimation from terrestrial laser scanning by circle-fitting methods

NASA Astrophysics Data System (ADS)

Koreň, Milan; Mokroš, Martin; Bucha, Tomáš

2017-12-01

This study compares the accuracies of diameter at breast height (DBH) estimations by three initial (minimum bounding box, centroid, and maximum distance) and two refining (Monte Carlo and optimal circle) circle-fitting methods The circle-fitting algorithms were evaluated in multi-scan mode and a simulated single-scan mode on 157 European beech trees (Fagus sylvatica L.). DBH measured by a calliper was used as reference data. Most of the studied circle-fitting algorithms significantly underestimated the mean DBH in both scanning modes. Only the Monte Carlo method in the single-scan mode significantly overestimated the mean DBH. The centroid method proved to be the least suitable and showed significantly different results from the other circle-fitting methods in both scanning modes. In multi-scan mode, the accuracy of the minimum bounding box method was not significantly different from the accuracies of the refining methods The accuracy of the maximum distance method was significantly different from the accuracies of the refining methods in both scanning modes. The accuracy of the Monte Carlo method was significantly different from the accuracy of the optimal circle method in only single-scan mode. The optimal circle method proved to be the most accurate circle-fitting method for DBH estimation from point clouds in both scanning modes.

COMPLETENESS OF CIRCLE OF WILLIS IN ASYMPTOMATIC AND SYMPTOMATIC EXTRACRANIAL CAROTID DISEASE.

PubMed

Manojlovic, Vladimir; Popovic, Vlandan; Nikoloc, Dragan; Milosevic, Dorde; Pasternak, Janko; Budakov, Nebojsa

2016-11-01

This research has been aimed at determining whether incomplete Circle of Willis in patients with significant extracranial carotid stenosis is associated with a higher incidence of neurological symptomatology and/or ischemnic cerebral lesions. The research was conducted as a prospective study which comprised 211 patients who underwent surgical treatment of extracranial carotid disease at the Department of Vascular Surgery in Novi Sad and 102 patients in the control group. Each patient underwent preoperative magnetic resonance imaging and magnetic resonance angiography with visualization of cerebral parenchyma. extracranial and intracranial cerebral circulation. Assessment of Circle of Willis morphology was performed by 3D time-of-fight magnetic resonance angiogram sequence analysis. The patients were divided into two groups: group I - the patients with'complete Circle of Willis and group II - the patients with incomplete Circle of Willis i.e. with the disruption of anterior and/ or ipsilateral posterior circulation - regarding the side of signif icant carotid stenosis. Out of 211 patients who -were operated during a two-year period, 133 had the complete Circle of Willis. while 78 patients had the incomplete Circle of Willis. Out of 111 patients with symptomatic carotid disease or silent cerebral infarction, 52.5% (58) had the complete Circle of' Willis and 47.5% (53) had the incomplete Circle of Willis. It was shown to be statistically different (P = 0.0146) in relation with the asymptomatic group of patients (100), where the frequency of the complete Circle of Willis was 75% (75) while the insufficiency of anterior or ipsilateral posterior collateral ization was found in 25% (25). In the control group there were significantly fewer cases of developed collateral flow and the complete Circle of Willis (41%) compared to the operated patients with extracranial carotid stenosis (63%) (P= 0.0003). Incompleteness of Circle of Willis is associated with more frequent occurrence of neurological symptomatology or ischemic lesions of brain parenchyma in operated patients with significant extracranial carotid stenosis. The control group without extracranial carotid stenosis had less developed collaterals of Circle of Willis compared to extracranial carotid patients.

Correlation Between the Integrity of the Circle of Willis and the Severity of Initial Noncardiac Cerebral Infarction and Clinical Prognosis

PubMed Central

Zhou, Houshi; Sun, Jian; Ji, Xiaotan; Lin, Jing; Tang, Shujin; Zeng, Jinsheng; Fan, Yu-hua

2016-01-01

Abstract The quality of collateral circulation affects the severity and prognosis of stroke patients. The effect of the circle of Willis, which is the primary collateral circulation, on ischemic stroke has attracted significant attention. This study was designed to investigate the effect of different circles of Willis types on stroke severity and prognosis in patients with noncardiac stroke. A total of 376 patients with noncardiac ischemic stroke, who were treated by the specialty team of cerebrovascular diseases at the First Affiliated Hospital of Sun Yat-sen Hospital, were successively enrolled in this study. The detailed clinical characteristics of the patients were recorded upon admission, including risk factors of vascular disease and National Institutes of Health Stroke Scale (NIHSS) scores. The patients were divided into groups of different circles of Willis types based on magnetic resonance angiography (MRA) that was performed within 3 days of admission—type I: complete circle of Willis; type II: complete anterior half of the circle of Willis and incomplete posterior half of the circle of Willis; type III: incomplete anterior half of the circle of Willis and complete posterior half of the circle of Willis; and type IV: incomplete anterior and posterior halves of the circle of Willis. Patients were re-evaluated for NIHSS scores at discharge and after discharge. The modified Rankin score (mRS) was recorded for 90 days, and stroke recurrence and death after 90 days were also recorded until the end of the study. The 376 patients were divided into 4 groups based on the MRA—type I group: 92 patients (24.5%); type II group: 215 patients (57.2%); type III group: 12 patients (3.2%), and type IV group: 57 patients (15.2%). NIHSS scores at admission and discharge were significantly lower for the type I group compared with those for the type II and type IV groups (P < 0.05). NIHSS scores were higher in the groups with an incomplete circle of Willis compared with the group with a complete circle of Willis. A poor recovery rate was highest for the type IV group, whereas a good recovery rate was highest for the type I group. The logistic regression analysis showed that a complete circle of Willis was one of the predictors of suitable recovery (odds ratio [OR] = 0.708, 95% confidence interval [CI]: 0.554–0.906). Circle of Willis type was associated with stroke severity and patient prognosis, whereas an incomplete circle of Willis was associated with more severe conditions and a higher 90-day poor diagnosis rate. A complete circle of Willis was an independent predictor of good prognosis. PMID:26962785

What Works: Study Circles in the Real World. Best Practices for Producing Community-Wide Study Circles.

ERIC Educational Resources Information Center

Mengual, Gloria

This document, which is based on information gathered during a 1998 study of how study circle programs contribute to community problem solving, presents best practices for producing community-wide study circles. The best practices are illustrated through stories that are grouped into five sections on the following themes: (1) creating a…

"Quality Circles": A Strategy for Personal and Curriculum Development. Coombe Lodge Working Paper. Information Bank Number 1803.

ERIC Educational Resources Information Center

Field, M. J.; Harrison, A. B.

Quality circles attempt to satisfy both task and personal needs through staff involvement in solving work-related problems. This paper summarizes quality circle theory, applies it to school settings, and suggests a framework for introducing the process to educational institutions. After briefly defining quality circles, the article presents two…

Mismanagement and Quality Circles: How Middle Managers Influence Direct Participation.

ERIC Educational Resources Information Center

Brennan, Maire

1991-01-01

Case studies of five Scottish companies found that four of their quality circles programs had ceased. Essential to the success of quality circles were changes in the systems of reward, communication, and decision making and the cooperation and support of middle managers, who may see quality circles as a threat and who control the resources they…

Expanding-Circle Students Learning "Standard English" in the Outer-Circle Asia

ERIC Educational Resources Information Center

Kobayashi, Yoko

2011-01-01

Drawing upon Kachru's concentric circles of English, the present study explores whether middle-class Japanese students who chose to study English solo at private language schools in Singapore diverge from many others who (wish to) study inner-circle English. The study is stimulated by the repeated interdisciplinary findings that, in spite of the…

Circles of Support and Personalization: Exploring the Economic Case

ERIC Educational Resources Information Center

Wistow, Gerald; Perkins, Margaret; Knapp, Martin; Bauer, Annette; Bonin, Eva-Maria

2016-01-01

Circles of Support aim to enable people with learning disabilities (and others) to live full lives as part of their communities. As part of a wider study of the economic case for community capacity building conducted from 2012 to 2014, we conducted a mixed methods study of five Circles in North West England. Members of these Circles were…

Children with Autism and Peer Group Support: "Using Circles of Friends".

ERIC Educational Resources Information Center

Whitaker, Philip; Barratt, Penny; Joy, Helen; Potter, Mo; Thomas, George

1998-01-01

Explains the "circle of friends approach" as one strategy aimed at using peer group support to promote the inclusion of children with autism into mainstream schools. It describes use of the approach with six autistic children in years 3 to 10 of British mainstream schools. Evaluation comments by the circle leaders, circle members, and…

The Chicken and the Egg: Inviting Response and Talk through Socratic Circles

ERIC Educational Resources Information Center

Styslinger, Mary E.; Pollock, Timothy

2010-01-01

This collaborative inquiry answers the following questions: 1) What is the nature of talk during Socratic Circles? 2) What is student response to talk? 3) How might knowing more about student response to talk and the nature of talk improve teaching during Socratic Circles? The article first describes the process of implementing Socratic Circles,…

Getting Started with Literature Circles. The Bill Harp Professional Teachers Library Series.

ERIC Educational Resources Information Center

Noe, Katherine L. Schlick; Johnson, Nancy J.

Designed to help teachers get started using literature circles in their classrooms, this book gives teachers a boost to begin, offers some insights from other teachers, and helps teachers clarify where to go next. It notes that literature circles (or literature study groups, book clubs, or discussion circles) take many forms and engage students in…

Guided Discovery of the Nine-Point Circle Theorem and Its Proof

ERIC Educational Resources Information Center

Buchbinder, Orly

2018-01-01

The nine-point circle theorem is one of the most beautiful and surprising theorems in Euclidean geometry. It establishes an existence of a circle passing through nine points, all of which are related to a single triangle. This paper describes a set of instructional activities that can help students discover the nine-point circle theorem through…

Ecohydrological interactions within "fairy circles" in the Namib Desert: Revisiting the self-organization hypothesis

NASA Astrophysics Data System (ADS)

Ravi, Sujith; Wang, Lixin; Kaseke, Kudzai Farai; Buynevich, Ilya V.; Marais, Eugene

2017-02-01

Vegetation patterns such as rings, bands, and spots are recurrent characteristics of resource-limited arid and semiarid ecosystems. One of the most recognizable vegetation patterns is the millions of circular patches, often referred to as "fairy circles," within the arid grassland matrix extending over hundreds of kilometers in the Namib Desert. Several modeling studies have highlighted the role of plant-soil interactions in the formation of these fairy circles. However, little is known about the spatial and temporal variabilities of hydrological processes inside a fairy circle. In particular, a detailed field assessment of hydrological and soil properties inside and outside the fairy circles is limited. We conducted extensive measurements of infiltration rate, soil moisture, grass biometric, and sediment grain-size distribution from multiple circles and interspaces in the Namib Desert. Our results indicate that considerable heterogeneity in hydrological processes exists within the fairy circles, resulting from the presence of coarser particles in the inner bare soil areas, whereas concentration of fine soil occurs on the vegetated edges. The trapping of aeolian and water-borne sediments by plants may result in the observed soil textural changes beneath the vegetation, which in turn, explains the heterogeneity in hydrological processes such as infiltration and runoff. Our investigation provides new insights and experimental data on the ecohydrological processes associated with fairy circles, from a less studied location devoid of sand termite activity within the circles. The results seem to provide support to the "self-organization hypothesis" of fairy circle formation attributed to the antiphase spatial biomass-water distributions.

A Spring Playscape Project: Building a Tree Circle

ERIC Educational Resources Information Center

Keeler, Rusty

2009-01-01

The Tree Circle is a green gathering area for children made by planting trees in a circle. For children, the Tree Circle becomes a magical place for dramatic play, quiet retreat, or lively nature exploration. For teachers and parents it becomes a shady grove for snacks and stories. The trees create a sweet spot that changes during the seasons and…

National Forest System working circles: a question of size and ownership composition

Treesearch

Robert J. Hrubes

1976-01-01

Allowable-cut (potential yield) levels on National Forest land are determined for planning units called working circles. The size of working circles has been increased over the past 30 years to the present scale which is often coincident with National Forest boundaries. Larger working circles have recently been considered because of the anticipated impacts on timber...

The combination of circle topology and leaky integrator neurons remarkably improves the performance of echo state network on time series prediction.

PubMed

Xue, Fangzheng; Li, Qian; Li, Xiumin

2017-01-01

Recently, echo state network (ESN) has attracted a great deal of attention due to its high accuracy and efficient learning performance. Compared with the traditional random structure and classical sigmoid units, simple circle topology and leaky integrator neurons have more advantages on reservoir computing of ESN. In this paper, we propose a new model of ESN with both circle reservoir structure and leaky integrator units. By comparing the prediction capability on Mackey-Glass chaotic time series of four ESN models: classical ESN, circle ESN, traditional leaky integrator ESN, circle leaky integrator ESN, we find that our circle leaky integrator ESN shows significantly better performance than other ESNs with roughly 2 orders of magnitude reduction of the predictive error. Moreover, this model has stronger ability to approximate nonlinear dynamics and resist noise than conventional ESN and ESN with only simple circle structure or leaky integrator neurons. Our results show that the combination of circle topology and leaky integrator neurons can remarkably increase dynamical diversity and meanwhile decrease the correlation of reservoir states, which contribute to the significant improvement of computational performance of Echo state network on time series prediction.

Fabrication and characteristics of thin disc piezoelectric transformers based on piezoelectric buzzers with gap circles.

PubMed

Chang, Kuo-Tsai; Lee, Chun-Wei

2008-04-01

This paper investigates design, fabrication and test of thin disc piezoelectric transformers (PTs) based on piezoelectric buzzers with gap circles at different diameters of the gap circles. The performance test is focused on characteristics of voltage gains, including maximum voltage gains and maximum-gain frequencies, for each piezoelectric transformer under different load conditions. Both a piezoelectric buzzer and a gap circle on a silver electrode of the buzzer are needed to build any type of the PTs. Here, the gap circle is used to form a ring-shaped input electrode and a circle-shaped output electrode for each piezoelectric transformer. To do so, both structure and connection of a PT are first expressed. Then, operating principle of a PT and its related vibration mode observed by a carbon-power imaging technique are described. Moreover, an experimental setup for characterizing each piezoelectric transformer is constructed. Finally, effects of diameters of the gap circles on characteristics of voltage gains at different load resistances are discussed.

A programmable systolic array correlator as a trigger processor for electron pairs in rich (ring image Cherenkov) counters

NASA Astrophysics Data System (ADS)

Männer, R.

1989-12-01

This paper describes a systolic array processor for a ring image Cherenkov counter which is capable of identifying pairs of electron circles with a known radius and a certain minimum distance within 15 μs. The processor is a very flexible and fast device. It consists of 128 x 128 processing elements (PEs), where one PE is assigned to each pixel of the image. All PEs run synchronously at 40 MHz. The identification of electron circles is done by correlating the detector image with the proper circle circumference. Circle centers are found by peak detection in the correlation result. A second correlation with a circle disc allows circles of closed electron pairs to be rejected. The trigger decision is generated if a pseudo adder detects at least two remaining circles. The device is controlled by a freely programmable sequencer. A VLSI chip containing 8 x 8 PEs is being developed using a VENUS design system and will be produced in 2μ CMOS technology.

Circles South East: the first 10 years 2002-2012.

PubMed

Bates, Andrew; Williams, Dominic; Wilson, Chris; Wilson, Robin J

2014-07-01

This article describes the first 10 years of the implementation of Circles of Support and Accountability (Circles) in the management of sexual offenders in South-East England by Circles South East (CSE). The Circles of 71 core members are reviewed in detail, with reference to demographic data, offense and sentencing histories, risk assessment data, and considerations regarding Multi-Agency Public Protection Arrangements. A group of 71 comparison subjects who were referred to CSE and deemed suitable for but did not receive the service was identified. Follow-up behaviors of both groups are examined (including all forms of reconviction, breach of orders, and prison recall). Over a comparable follow-up period of 55 months, the incidence of violent and contact sexual reconviction in the comparison group was significantly higher than for the Circles cohort. Comparisons are made between expected and actual levels of sexual reconviction, with the Circles cohort showing lower than expected rate of sexual reconviction but not to a statistically significant degree. © The Author(s) 2013.

Wear simulation of apex seal in rotary engine under mixed lubrication

NASA Astrophysics Data System (ADS)

Jiang, Hanying; Zuo, Zhengxing; Liu, Jinxiang

2018-05-01

In this work, the wear of apex seal's running face under mixed lubrication is studied. Numerical simulation is carried out by employing the couple model of Reynolds equation, Greenwood and Tripp model and Archard's wear law. The simulation is performed both for one circle and multi circle. In the multi circle simulation, the change of contact position due to wear is considered. A method that is able to find the new contact position based on the updated apex seal's contour profile is proposed, validated and used. The result of multi circle simulation indicates that contact position changes obviously around the maximum swing angles both on leading and trailing sides with the increase number of circles. The wear depth distribution becomes more uniform with the increase of operation circle number.

Algebraic criteria for positive realness relative to the unit circle.

NASA Technical Reports Server (NTRS)

Siljak, D. D.

1973-01-01

A definition is presented of the circle positive realness of real rational functions relative to the unit circle in the complex variable plane. The problem of testing this kind of positive reality is reduced to the algebraic problem of determining the distribution of zeros of a real polynomial with respect to and on the unit circle. Such reformulation of the problem avoids the search for explicit information about imaginary poles of rational functions. The stated algebraic problem is solved by applying the polynomial criteria of Marden (1966) and Jury (1964), and a completely recursive algorithm for circle positive realness is obtained.

Influence of off-great-circle propagation of Rayleigh waves on event-based surface wave tomography in Northeast China

NASA Astrophysics Data System (ADS)

Chen, Haopeng; Ni, Sidao; Chu, Risheng; Chong, Jiajun; Liu, Zhikun; Zhu, Liangbao

2018-05-01

Surface waves are generally assumed to propagate along great-circle paths in most surface-wave tomography. However, when lateral heterogeneity is strong, off-great-circle propagation may occur and deteriorate surface wave tomography results based on the great-circle assumption. In this study, we used teleseismic waveforms recorded by the NECESSArray in Northeast China to study off-great-circle propagation of Rayleigh waves using the beamforming method and evaluated the influence of off-great-circle propagation on event-based surface wave tomography. The results show that arrival angle anomalies generally increase with decreasing period. The arrival angle anomalies at 60 and 50 s periods are smaller than that at 40 and 30 s periods, which indicates that the off-great-circle propagation is relatively weak for longer periods. At 30 s period, the arrival angle anomalies are relatively larger and some of the measurements can exceed 20°, which represents a strong off-great-circle propagation effect. In some areas, the arrival angle anomalies of adjacent events differ significantly, which may be attributed to multipathing propagation of surface waves. To evaluate the influence of off-great-circle propagation on event-based surface wave tomography, we used measured arrival angle anomalies to correct two-station phase velocity measurements, and performed azimuthal anisotropy tomography using dispersion datasets with and without the arrival angle correction. At longer periods, such as 60 s, the influence of off-great-circle propagation on surface wave tomography is weak even though the corrected model has better data fit than the uncorrected model. However, the influence of off-great-circle propagation is non-negligible at short periods. The tomography results at 30 s period show that the differences in phase velocity, the strength of anisotropy and the fast direction can be as large as 1.5 per cent, 1.0 per cent and 30°, respectively. Furthermore, the corrected phase velocity is systematically lower than that without correction. This study illustrates the necessity of studying the off-great-circle propagation of surface waves to improve the accuracy of event-based surface wave tomography, especially for shorter periods.

Near-infrared chemical imaging (NIR-CI) as a process monitoring solution for a production line of roll compaction and tableting.

PubMed

Khorasani, Milad; Amigo, José M; Sun, Changquan Calvin; Bertelsen, Poul; Rantanen, Jukka

2015-06-01

In the present study the application of near-infrared chemical imaging (NIR-CI) supported by chemometric modeling as non-destructive tool for monitoring and assessing the roller compaction and tableting processes was investigated. Based on preliminary risk-assessment, discussion with experts and current work from the literature the critical process parameter (roll pressure and roll speed) and critical quality attributes (ribbon porosity, granule size, amount of fines, tablet tensile strength) were identified and a design space was established. Five experimental runs with different process settings were carried out which revealed intermediates (ribbons, granules) and final products (tablets) with different properties. Principal component analysis (PCA) based model of NIR images was applied to map the ribbon porosity distribution. The ribbon porosity distribution gained from the PCA based NIR-CI was used to develop predictive models for granule size fractions. Predictive methods with acceptable R(2) values could be used to predict the granule particle size. Partial least squares regression (PLS-R) based model of the NIR-CI was used to map and predict the chemical distribution and content of active compound for both roller compacted ribbons and corresponding tablets. In order to select the optimal process, setting the standard deviation of tablet tensile strength and tablet weight for each tablet batch was considered. Strong linear correlation between tablet tensile strength and amount of fines and granule size was established, respectively. These approaches are considered to have a potentially large impact on quality monitoring and control of continuously operating manufacturing lines, such as roller compaction and tableting processes. Copyright © 2015 Elsevier B.V. All rights reserved.

Layered composites made from bimetallic strips produced by plasma spraying of TiAl on niobium

NASA Astrophysics Data System (ADS)

Burmistrov, V. I.; Antonova, A. V.; Povarova, K. B.; Bannykh, I. O.

2007-12-01

The production and structure of a multilayer TiAl/Nb composite material made from bimetallic TiAl/Nb strips fabricated by plasma spraying of TiAl granules onto niobium plates are studied. Here, 3-mm-and 2-mm-thick plates of a layered composite material (LCM) are produced by hot isostatic pressing of a stack of 35 bimetallic plates followed by hot rolling (the total degree of reduction is 78.6 and 85.7%, respectively). The LCM consists of discontinuous TiAl layers separated by niobium layers, and the adhesion between the layers is good. Diffusional intermediate layers form at the TiAl/Nb interfaces in the 3-mm-thick LCM and consist of the following two solid solutions: an α2-Ti3Al-based solid solution contains up to 28 at % Nb, and a niobiumbased solid solution contains up to 27 at % Ti and 32 at % Al. The diffusional intermediate layers in the 2-mmthick LCM plates consist of an α2-Ti3Al-based solid solution with up to 16.0 at % Nb; a τ-Ti3Al2Nb-or Ti4Al3Nb-based solid solution with 51.5 at % Ti, 32 at % Al, and 16.5 at % Nb; and a niobium-based solid solution with up to 22 at % Ti and 30.5 at % Al. When a bimetallic TiAl/Nb strip is fabricated by plasma spraying of granules of the Ti-48 at % Al alloy, this alloy is depleted of aluminum to 42 45 at %, and the fraction of the α2-Ti3Al phase in the sprayed layer increases. When the LCM is produced by hot isostatic pressing followed by hot rolling, the layer of plain niobium (Nb1) dissolves up to 5 at % Ti and 7 at % Al.

Quality Control in construction.

DTIC Science & Technology

1984-01-01

behavioral scientists. In 1962, Dr. Kaoru Ishikawa gave shape to the form of training which featured intradepartmental groups of ten or so workers seated...and Japanese circles bears closer scrutiny. 4.3.1 Japanese Ingredients of Quality The founder of quality circles, Dr. Kaoru Ishikawa , gives six...around 51 a table; hence the name Quality Control Circle. 4 Dr. 0 Ishikawa was an engineering professor at Tokyo University, and the circles were

Circle of influence

NASA Astrophysics Data System (ADS)

Robinson, Andrew

2018-04-01

The founder of the Vienna Circle – a polymathic and influential group of intellectuals dedicated to the philosophy of science from the late 1920s until the Nazi takeover of Austria in 1938 – was German philosopher and physicist Moritz Schlick. Karl Sigmund's latest book – Exact Thinking in Demented Times: the Vienna Circle and the Epic Quest for the Foundations of Science – tells the story of the Vienna Circle's ideas and personalities.

Calculation of Latitude and Longitude for Points on Perimeter of a Circle on a Sphere

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morris, Heidi E.

2015-08-14

This document describes the calculation of the Earth-Centered Earth Fixed (ECEF) coordinates for points lying on the perimeter of a circle. Here, the perimeter of the circle lies on the surface of the sphere and the center of the planar circle is below the surface. These coordinates are converted to latitude and longitude for mapping fields on the surface of the earth.

Empirical Evaluation of Different Feature Representations for Social Circles Detection

DTIC Science & Technology

2015-06-16

study and compare the performance on the available labelled Facebook data from the Kaggle competition on learning social circles in networks . We...Kaggle competition on learning social circles in networks [5]. The data consist of hand- labelled friendship egonets from Facebook and a set of 57...16. SECURITY CLASSIFICATION OF: Social circles detection is a special case of community detection in social network that is currently attracting a

Practical Environmental Education and Local Contribution in the Environmental Science Laboratory Circle in the College of Science and Technology in Nihon University

NASA Astrophysics Data System (ADS)

Taniai, Tetsuyuki; Ito, Ken-Ichi; Sakamaki, Hiroshi

In this paper, we presented a method and knowledge about a practical and project management education and local contribution obtained through the student activities of “Environmental science laboratory circle in the College of Science and technology in Nihon University” from 1991 to 2001. In this circle, four major projects were acted such as research, protection, clean up and enlightenment projects. Due to some problems from inside or outside of this circle, this circle projects have been stopped. The diffusion and popularization of the internet technology will help to resolve some of these problems.

Numerical Grid Generation. Proceedings of a Symposium on the Numerical Generation of Curvilinear Coordinate Systems and their Use in the Numerical Solution of Partial Differential Equations, held April 1982, Nashville, Tennessee

DTIC Science & Technology

1982-04-01

the transformation 2 1 V I " |€ , (22) 121 I which transforms a unit circle in the Z plane to a unit upper half ...circle (and to the real axis from -1. to 1.) in the 4 plane as illustrated in Fig. 6. I Zpbns rpIUII A A , FIGURE 6. , CIRCLE TO HALF CIRCLE MAPPING The ...an airfoil, or inlet, etc. ... ) to a rectangle (or equivalently to a circle or half plane ). The cumputing time required for this step is

Component analysis and synthesis of dark circles under the eyes using a spectral image

NASA Astrophysics Data System (ADS)

Akaho, Rina; Hirose, Misa; Ojima, Nobutoshi; Igarashi, Takanori; Tsumura, Norimichi

2017-02-01

This paper proposes to apply nonlinear estimation of chromophore concentrations: melanin, oxy-hemoglobin, deoxyhemoglobin and shading to the real hyperspectral image of skin. Skin reflectance is captured in the wavelengths between 400nm and 700nm by hyperspectral scanner. Five-band wavelengths data are selected from skin reflectance. By using the cubic function which obtained by Monte Carlo simulation of light transport in multi-layered tissue, chromophore concentrations and shading are determined by minimize residual sum of squares of reflectance. When dark circles are appeared under the eyes, the subject looks tired and older. Therefore, woman apply cosmetic cares to remove dark circles. It is not clear about the relationship between color and chromophores distribution in the dark circles. Here, we applied the separation method of the skin four components to hyperspectral image of dark circle, and the separated components are modulated and synthesized. The synthesized images are evaluated to know which components are contributed into the appearance of dark circles. Result of the evaluation shows that the cause of dark circles for the one subject was mainly melanin pigmentation.

Cross-directional interlocking of rolls in an air press of a papermaking machine

DOEpatents

Beck, David A.; Gorshe, Thomas

2003-05-13

An air press for pressing a paper web is composed of a plurality of rolls including at least a first roll and a second roll. The first roll and the second roll are positioned adjacent one another and form a first nip therebetween. Further, the first roll and the second roll each have a roll end, the roll end of the first roll adjoining the roll end of the second roll. A bevel plate is attached to the roll end of the first roll, the bevel plate having at least a first angled plate face. A seal ring is positioned adjacent the roll end of the second roll, the seal ring being juxtaposed to the bevel plate. The seal ring has at least a first angled ring face, and the first angled ring face mates with the first angled plate face.

Traffic Circle Model

DOT National Transportation Integrated Search

1971-05-01

The report describes a dynamic model of a traffic circle which has been implemented on a CRT display terminal. The model includes sufficient parameters to allow changes in the structure of the traffic circle, the frequency of traffic introduced to th...

Can the Expanding Circle Own English? Comments on Yoo's "Nonnative Teachers in the Expanding Circle and the Ownership of English"

ERIC Educational Resources Information Center

Ren, Wei

2014-01-01

Yoo's (2014) article raises a number of questions concerning local teachers' status and the ownership of English in the Expanding Circle. In this article, I address five issues that I see as most important relating to the ownership of English and empowering local teachers in the Expanding Circle. I provide up-to-date evidence of World…

Circles of Support and Accountability for Sex Offenders: A Systematic Review of Outcomes.

PubMed

Clarke, Martin; Brown, Susan; Völlm, Birgit

2017-08-01

We conducted a systematic review of studies reporting on the effectiveness of Circles of Support and Accountability (Circles). Circles use volunteers to provide support for sex offenders living in the community. We searched 10 databases up to the end of 2013 and identified 3 relevant outcome studies. An additional 12 papers or reports were identified by searching reference lists, Google, and contacting key authors and Circles providers to obtain unpublished data. These 15 studies comprised one randomized controlled trial, three retrospective cohorts with matched controls, and 11 case series. The majority reported measures of recidivism, particularly reconviction. The 4 studies with controls generally reported that participation in Circles was associated with lower recidivism although there were few statistically significant differences. Few studies examined changes in risk or psychosocial outcomes. A number of methodological issues are discussed. Longer term, prospective follow-up studies with control groups are required to address these issues.

SPRUCE Deep Peat Heating Manipulations: in situ Methods to Characterize the Response of Deep Peat to Warming

NASA Astrophysics Data System (ADS)

Hanson, P. J.; Riggs, J. S.; Barbier, C. N.; Nettles, W. R., IV; Phillips, J. R.; Hook, L.

2014-12-01

Deep soil heating infrastructure was completed in 2014 for a peatland whole-ecosystem warming study that will include air warming starting in 2015 (SPRUCE; http://mnspruce.ornl.gov). In June 2014, we initiated deep soil heating to test the responsiveness of deep peat carbon stocks, microbial communities and biogeochemical cycling processes to heating at 4 warming levels (+2.25, +4.5, +6.75 and +9 °C; 2 replicate plots) compared to fully-constructed control plots (+0 °C; 2 replicate plots). The warming treatments were deployed over eight 113 m2 areas using circular arrays of low-wattage (W) electrical resistance heaters. Perimeter heating was achieved by an exterior circle of 48 100W heaters that apply heat from the surface to a depth of 3 meters. Heating within the study area was accomplished utilizing three zones of 100W "deep only" heaters: an intermediate circle of 12 units, an interior circle of 6 units and one unit placed at the plot center. Heating elements inside the study area apply heat only from -2 to -3 m to keep active heater surfaces away from measured peat volumes. With an average peat depth of 2.5 meters this system was able to warm approximately 113 of the 282 m3 of peat within each target plot. In the absence of the air warming cap, in situ deep peat heating is only effective at sustaining warming in the deep peat layers. Warming levels at depth were achieved over a 25-day (+ 2.25 °C) to a 60-day (+9 °C) period depending on the target treatment temperatures in agreement with a priori energy balance model simulations. Homogeneous temperature distributions between heaters at a given depth interval continued to develop after these targets were reached. Biological and biogeochemical responses to these manipulations are being actively assessed. After one month of transient heating, data for ground-level surface flux of CO2 and CH4 had not shown changes from deep peat heating, but they continue to be tracked and will be summarized in this and related talks.

Fine-scale Patterns in Thaw Depth, Micro-relief, and Ground Cover on Non-sorted Circles and Small Patterned Ground Features Along a Climatic Gradient From Low to High Arctic

NASA Astrophysics Data System (ADS)

Okie, J.; Gould, W. A.; González, G.

2006-12-01

Patterned ground is a ubiquitous feature in the Arctic and the related variation in microtopographic relief strongly affects biotic and abiotic patterns and processes. Patterned ground features are polygenic in origin and are often found superimposed in a complex pattern of multiple features. We investigated the relationship between thaw depth, micro-relief, the cover of vascular, bryophyte, cryptogamic crust and bare ground along transects traversing non-sorted circles and small non-sorted polygons at 8 research sites along a climatic gradient in bioclimatic subzones A-E in the North American Arctic. Non-sorted circles are the result of differential frost heave with circle centers typically showing greater heave during freezing than inter circle areas. Differential heave is a function of climate, soil texture, soil moisture, and vegetation cover. Differential heave and subsidence creates fine-scale gradients in microtopography that affect soil moisture, exposure to winds, and development of vegetation and soils. Non-sorted circles typically range from 20 to 200 cm in diameter and are most common in subzones C-E. Often superimposed on these features are the development of small non-sorted polygons 10-30 cm in diameter, and fine-scale desiccation cracking at a scale of less than 10 cm. These are most common in subzones A-C. We established three 20 m transects in zonal vegetation at each site. Thaw depth, micro-relief, and ground cover were measured at 10 cm intervals along each transect. Additionally, we measured vascular plant beta diversity in a set of 25 x 25 cm quadrates on 15 circles and 15 inter circles at each site. The resulting pattern of thaw depth and micro-relief is correlated with both summer temperatures and vegetation cover. The variability and degree of micro-relief decrease from the Low to the High Arctic. Non-sorted circle centers had deeper active layer than inter circle areas along the gradient. Thaw depths increase linearly with the degree of bare ground and nonlinearly with summer warmth. This unimodal pattern of shallower active layer at the warmest and coldest sites is due to the interaction of climate and the insulating vegetation layer. Greatest thaw depths are found on bare non-sorted circles in subzone C. Beta diversity is greatest in subzone D, where vegetated inter circle areas differ markedly from more barren non- sorted circles.

Controlled-force end seal arrangement for an air press of a papermaking machine

DOEpatents

Beck, David A.

2003-07-08

An air press for pressing a fiber web includes a plurality of rolls and a pair of end seal arrangements. Of the plurality of rolls, each pair of adjacent rolls forms a nip therebetween. Further, each roll has a pair of roll ends, the plurality of rolls together forming two sets of roll ends. Each end seal arrangement coacts with one set of roll ends, the plurality of rolls and the pair of end seal arrangements together defining an air press chamber having an air chamber pressure. Each end seal arrangement is composed of at least one roll seal, including a first roll seal, and an adjustable bias mechanism. Each roll seal forms a seal with at least one roll end, and one side of the first roll seal being exposed to the air chamber pressure. The adjustable bias mechanism is configured for controlling a position of each roll seal relative to a respective at least one roll end and for adjusting a seal force between the roll seal and the respective at least one roll end.

Analysis of a model race car

NASA Astrophysics Data System (ADS)

Coletta, Vincent P.; Evans, Jonathan

2008-10-01

We analyze the motion of a gravity powered model race car on a downhill track of variable slope. Using a simple algebraic function to approximate the height of the track as a function of the distance along the track, and taking account of the rotational energy of the wheels, rolling friction, and air resistance, we obtain analytic expressions for the velocity and time of the car as functions of the distance traveled along the track. Photogates are used to measure the time at selected points along the track, and the measured values are in excellent agreement with the values predicted from theory. The design and analysis of model race cars provides a good application of principles of mechanics and suggests interesting projects for classes in introductory and intermediate mechanics.

The genomes of four novel begomoviruses and a new Sida micrantha mosaic virus strain from Bolivian weeds.

PubMed

Wyant, Patrícia Soares; Gotthardt, Diether; Schäfer, Benjamin; Krenz, Björn; Jeske, Holger

2011-02-01

Begomovirus is the largest genus within the family Geminiviridae and includes economically important plant DNA viruses infecting a broad range of plant species and causing devastating crop diseases, mainly in subtropical and tropical countries. Besides cultivated plants, many weeds act as virus reservoirs. Eight begomovirus isolates from Bolivian weeds were examined using rolling-circle amplification (RCA) and restriction fragment length polymorphism (RFLP). An efficient, novel cloning strategy using limited Sau3A digestion to obtain tandem-repeat inserts allowed the sequencing of the complete genomes. The viruses were classified by phylogenetic analysis as typical bipartite New World begomoviruses. Four of them represented distinct new virus species, for which the names Solanum mosaic Bolivia virus, Sida mosaic Bolivia virus 1, Sida mosaic Bolivia virus 2, and Abutilon mosaic Bolivia virus are proposed. Three were variants of a new strain of Sida micrantha mosaic virus (SimMV), SimMV-rho[BoVi07], SimMV-rho[Bo:CF1:07] and SimMV-rho[Bo:CF2:07], and one was a new variant of a previously described SimMV, SimMV-MGS2:07-Bo.

DNAzymes in DNA Nanomachines and DNA Analysis

NASA Astrophysics Data System (ADS)

He, Yu; Tian, Ye; Chen, Yi; Mao, Chengde

This chapter discusses our efforts in using DNAzymes in DNA nano-machines and DNA analysis systems. 10-23 DNAzymes can cleave specific phos-phodiester bonds in RNA. We use them to construct an autonomous DNA-RNA chimera nanomotor, which constantly extracts chemical energy from RNA substrates and transduces the energy into a mechanical motion: cycles of contraction and extension. The motor's motion can be reversibly turned on and off by a DNA analogue (brake) of the RNA substrate. Addition and removal of the brake stops and restarts, respectively, the motor's motion. Furthermore, when the RNA substrates are preorganized into a one-dimensional track, a DNAzyme can continuously move along the track so long as there are substrates available ahead. Based on a similar mechanism, a novel DNA detection system has been developed. A target DNA activates a DNAzyme to cleave RNA-containing molecular beacons (MB), which generates an enhanced fluorescence signal. A following work integrates two steps of signal amplifications: a rolling-circle amplification (RCA) to synthesize multiple copies of DNAzymes, and the DNAzymes catalyze a chemical reaction to generate a colorimetric signal. This method allows detection of DNA analytes whose concentration is as low as 1 pM.

Characterization of a novel papillomavirus species (ZcPV1) from two California sea lions (Zalophus californianus).

PubMed

Rivera, Rebecca; Robles-Sikisaka, Refugio; Hoffman, Elizabeth M; Stacy, Brian A; Jensen, Eric D; Nollens, Hendrik H; Wellehan, James F X

2012-03-23

A seven-year old California sea lion (Zalophus californianus) presented with focally extensive, bilaterally symmetric, proliferative axillary skin lesions and preputial lesions. A second California sea lion in the same population presented with similar proliferative lesions on the underside of the tail. Histopathology revealed epidermal hyperplasia with severe hyperkeratosis, with proliferating keratinocytes forming broad, branching pegs that extended into the dermis. Pan-papillomaviral consensus PCR was used to obtain initial E1 sequence template and the complete genome was determined using a combination of rolling circle amplification and specific-primer PCR. Analysis revealed a novel papillomavirus, Zalophus californianus papillomavirus 1 (ZcPV1), with seven open reading frames encoding five early proteins (E6, E7, E1, E2 and E4) and two late proteins (L1 and L2). Phylogenetic analysis revealed that (ZcPV1) is most closely related to Equine papillomavirus 1 (EcPV1) in the genus Zetapapillomavirus, and Canine papillomaviruses 3 and 4 (CPV3, CPV4) in the genus Chipapillomavirus. The lesions regressed without intervention over a period of several months. Copyright © 2011 Elsevier B.V. All rights reserved.

DNA Packaging Specificity of Bacteriophage N15 with an Excursion into the Genetics of a Cohesive End Mismatch

PubMed Central

Feiss, Michael; Young Min, Jea; Sultana, Sawsan; Patel, Priyal; Sippy, Jean

2015-01-01

During DNA replication by the λ-like bacteriophages, immature concatemeric DNA is produced by rolling circle replication. The concatemers are processed into mature chromosomes with cohesive ends, and packaged into prohead shells, during virion assembly. Cohesive ends are generated by the viral enzyme terminase, which introduces staggered nicks at cos, an approx. 200 bp-long sequence containing subsites cosQ, cosN and cosB. Interactions of cos subsites of immature concatemeric DNA with terminase orchestrate DNA processing and packaging. To initiate DNA packaging, terminase interacts with cosB and nicks cosN. The cohesive ends of N15 DNA differ from those of λ at 2/12 positions. Genetic experiments show that phages with chromosomes containing mismatched cohesive ends are functional. In at least some infections, the cohesive end mismatch persists through cyclization and replication, so that progeny phages of both allelic types are produced in the infected cell. N15 possesses an asymmetric packaging specificity: N15 DNA is not packaged by phages λ or 21, but surprisingly, N15-specific terminase packages λ DNA. Implications for genetic interactions among λ-like bacteriophages are discussed. PMID:26633301

Initiator-catalyzed self-assembly of duplex-looped DNA hairpin motif based on strand displacement reaction for logic operations and amplified biosensing.

PubMed

Bi, Sai; Yue, Shuzhen; Wu, Qiang; Ye, Jiayan

2016-09-15

Here we program an initiator-catalyzed self-assembly of duplex-looped DNA hairpin motif based on strand displacement reaction. Due to the recycling of initiator and performance in a cascade manner, this system is versatilely extended to logic operations, including the construction of concatenated logic circuits with a feedback function and a biocomputing keypad-lock security system. Compared with previously reported molecular security systems, the prominent feature of our keypad lock is that it can be spontaneously reset and recycled with no need of any external stimulus and human intervention. Moreover, through integrating with an isothermal amplification technique of rolling circle amplification (RCA), this programming catalytic DNA self-assembly strategy readily achieves sensitive and selective biosensing of initiator. Importantly, a magnetic graphene oxide (MGO) is introduced to remarkably reduced background, which plays an important role in enhancing the signal-to-noise ratio and improving the detection sensitivity. Therefore, the proposed sophisticated DNA strand displacement-based methodology with engineering dynamic functions may find broad applications in the construction of programming DNA nanostructures, amplification biosensing platform, and large-scale DNA circuits. Copyright © 2016 Elsevier B.V. All rights reserved.

Plasmid replication initiator RepB forms a hexamer reminiscent of ring helicases and has mobile nuclease domains

PubMed Central

Boer, D Roeland; Ruíz-Masó, José A; López-Blanco, José R; Blanco, Alexander G; Vives-Llàcer, Mireia; Chacón, Pablo; Usón, Isabel; Gomis-Rüth, F Xavier; Espinosa, Manuel; Llorca, Oscar; del Solar, Gloria; Coll, Miquel

2009-01-01

RepB initiates plasmid rolling-circle replication by binding to a triple 11-bp direct repeat (bind locus) and cleaving the DNA at a specific distant site located in a hairpin loop within the nic locus of the origin. The structure of native full-length RepB reveals a hexameric ring molecule, where each protomer has two domains. The origin-binding and catalytic domains show a three-layer α–β–α sandwich fold. The active site is positioned at one of the faces of the β-sheet and coordinates a Mn2+ ion at short distance from the essential nucleophilic Y99. The oligomerization domains (ODs), each consisting of four α-helices, together define a compact ring with a central channel, a feature found in ring helicases. The toroidal arrangement of RepB suggests that, similar to ring helicases, it encircles one of the DNA strands during replication to confer processivity to the replisome complex. The catalytic domains appear to be highly mobile with respect to ODs. This mobility may account for the adaptation of the protein to two distinct DNA recognition sites. PMID:19440202

Direct observation of single flexible polymers using single stranded DNA†

PubMed Central

Brockman, Christopher; Kim, Sun Ju

2012-01-01

Over the last 15 years, double stranded DNA (dsDNA) has been used as a model polymeric system for nearly all single polymer dynamics studies. However, dsDNA is a semiflexible polymer with markedly different molecular properties compared to flexible chains, including synthetic organic polymers. In this work, we report a new system for single polymer studies of flexible chains based on single stranded DNA (ssDNA). We developed a method to synthesize ssDNA for fluorescence microscopy based on rolling circle replication, which generates long strands (>65 kb) of ssDNA containing “designer” sequences, thereby preventing intramolecular base pair interactions. Polymers are synthesized to contain amine-modified bases randomly distributed along the backbone, which enables uniform labelling of polymer chains with a fluorescent dye to facilitate fluorescence microscopy and imaging. Using this approach, we synthesized ssDNA chains with long contour lengths (>30 μm) and relatively low dye loading ratios (~1 dye per 100 bases). In addition, we used epifluorescence microscopy to image single ssDNA polymer molecules stretching in flow in a microfluidic device. Overall, we anticipate that ssDNA will serve as a useful model system to probe the dynamics of polymeric materials at the molecular level. PMID:22956981

Surface invasive cleavage assay on a maskless light-directed diamond DNA microarray for genome-wide human SNP mapping.

PubMed

Nie, Bei; Yang, Min; Fu, Weiling; Liang, Zhiqing

2015-07-07

The surface invasive cleavage assay, because of its innate accuracy and ability for self-signal amplification, provides a potential route for the mapping of hundreds of thousands of human SNP sites. However, its performance on a high density DNA array has not yet been established, due to the unusual "hairpin" probe design on the microarray and the lack of chemical stability of commercially available substrates. Here we present an applicable method to implement a nanocrystalline diamond thin film as an alternative substrate for fabricating an addressable DNA array using maskless light-directed photochemistry, producing the most chemically stable and biocompatible system for genetic analysis and enzymatic reactions. The surface invasive cleavage reaction, followed by degenerated primer ligation and post-rolling circle amplification is consecutively performed on the addressable diamond DNA array, accurately mapping SNP sites from PCR-amplified human genomic target DNA. Furthermore, a specially-designed DNA array containing dual probes in the same pixel is fabricated by following a reverse light-directed DNA synthesis protocol. This essentially enables us to decipher thousands of SNP alleles in a single-pot reaction by the simple addition of enzyme, target and reaction buffers.

Rapidly expanding genetic diversity and host range of the Circoviridae viral family and other Rep encoding small circular ssDNA genomes.

PubMed

Delwart, Eric; Li, Linlin

2012-03-01

The genomes of numerous circoviruses and distantly related circular ssDNA viruses encoding a rolling circle replication initiator protein (Rep) have been characterized from the tissues of mammals, fish, insects, plants (geminivirus and nanovirus), in human and animal feces, in an algae cell, and in diverse environmental samples. We review the genome organization, phylogenetic relationships and initial prevalence studies of cycloviruses, a proposed new genus in the Circoviridae family. Viral fossil rep sequences were also recently identified integrated on the chromosomes of mammals, frogs, lancelets, crustaceans, mites, gastropods, roundworms, placozoans, hydrozoans, protozoans, land plants, fungi, algae, and phytoplasma bacterias and their plasmids, reflecting the very wide past host range of rep bearing viruses. An ancient origin for viruses with Rep-encoding small circular ssDNA genomes, predating the diversification of eukaryotes, is discussed. The cellular hosts and pathogenicity of many recently described rep-containing circular ssDNA genomes remain to be determined. Future studies of the virome of single cell and multi-cellular eukaryotes are likely to further extend the known diversity and host-range of small rep-containing circular ssDNA viral genomes. Copyright © 2011 Elsevier B.V. All rights reserved.

Classification of select category A and B bacteria by Fourier transform infrared spectroscopy

NASA Astrophysics Data System (ADS)

Samuels, Alan C.; Snyder, A. Peter; St. Amant, Diane; Emge, Darren K.; Minter, Jennifer; Campbell, Mark; Tripathi, Ashish

2008-04-01

Relatively few reports have investigated the determination and classification of pathogens such as the National Institute of Allergy and Infectious Diseases (NIAID) Category A Bacillus anthracis spores and cells (BA), Yersinia species, Francisella tularensis (FT), and Category B Brucella species from FTIR spectra. We investigated the classification ability of the Fourier transform infrared (FTIR) spectra of viable pathogenic and non-pathogenic NIAID Category A and B bacteria. The impact of different growth media, growth time and temperature, rolling circle filter of the data, and wavelength range were investigated for their microorganism differentiation. Various 2-D PC plots provided differential degrees of separation with respect to the four viable, bacterial genera including the BA sub-categories of pathogenic spores, vegetative cells, and nonpathogenic vegetative cells. FT spectra were separated from that of the three other genera. The BA pathogenic spore strains 1029, LA1, and Ames were clearly differentiated from the rest of the dataset. Yersinia species were distinctly separated from the remaining dataset and could also be classified by growth media. This work provided evidence that FTIR spectroscopy can separate the four major pathogenic bacterial genera of NIAID Category A and B biological threat agents.

Characterization of Human Papillomavirus Type 154 and Tissue Tropism of Gammapapillomaviruses

PubMed Central

Ure, Agustín Enrique; Forslund, Ola

2014-01-01

The novel human papillomavirus type 154 (HPV154) was characterized from a wart on the crena ani of a three-year-old boy. It was previously designated as the putative HPV type FADI3 by sequencing of a subgenomic FAP amplicon. We obtained the complete genome by combined methods including rolling circle amplification (RCA), genome walking through an adapted method for detection of integrated papillomavirus sequences by ligation-mediated PCR (DIPS-PCR), long-range PCR, and finally by cloning of four overlapping amplicons. Phylogenetically, the HPV154 genome clustered together with members of the proposed species Gammapapillomavirus 11, and demonstrated the highest identity in L1 to HPV136 (68.6%). The HPV154 was detected in 3% (2/62) of forehead skin swabs from healthy children. In addition, the different detection sites of 62 gammapapillomaviruses were summarized in order to analyze their tissue tropism. Several of these HPV types have been detected from multiple sources such as skin, oral, nasal, and genital sites, suggesting that the gammapapillomaviruses are generalists with a broader tissue tropism than previously appreciated. The study expands current knowledge concerning genetic diversity and tropism among HPV types in the rapidly growing gammapapillomavirus genus. PMID:24551244

Organization and evolution of highly repeated satellite DNA sequences in plant chromosomes.

PubMed

Sharma, S; Raina, S N

2005-01-01

A major component of the plant nuclear genome is constituted by different classes of repetitive DNA sequences. The structural, functional and evolutionary aspects of the satellite repetitive DNA families, and their organization in the chromosomes is reviewed. The tandem satellite DNA sequences exhibit characteristic chromosomal locations, usually at subtelomeric and centromeric regions. The repetitive DNA family(ies) may be widely distributed in a taxonomic family or a genus, or may be specific for a species, genome or even a chromosome. They may acquire large-scale variations in their sequence and copy number over an evolutionary time-scale. These features have formed the basis of extensive utilization of repetitive sequences for taxonomic and phylogenetic studies. Hybrid polyploids have especially proven to be excellent models for studying the evolution of repetitive DNA sequences. Recent studies explicitly show that some repetitive DNA families localized at the telomeres and centromeres have acquired important structural and functional significance. The repetitive elements are under different evolutionary constraints as compared to the genes. Satellite DNA families are thought to arise de novo as a consequence of molecular mechanisms such as unequal crossing over, rolling circle amplification, replication slippage and mutation that constitute "molecular drive". Copyright 2005 S. Karger AG, Basel.

Novel electrochemiluminescence of perylene derivative and its application to mercury ion detection based on a dual amplification strategy.

PubMed

Zhao, Jing; Lei, Yan-Mei; Chai, Ya-Qin; Yuan, Ruo; Zhuo, Ying

2016-12-15

In this paper, a novel covalently crosslinked perylene derivative (PTC-PEI) composed of polyethylenimine (PEI) and perylenetetracarboxylic acid (PTCA) has been first investigated for cathodic electrochemiluminescence (ECL) in an aqueous system with dissolved O2 as coreactant. The promising novel ECL materials of PTC-PEI exhibited admirable physical and chemical stability and high ECL intensity, which held an alternative way to construct ECL sensor with improved sensitivity. Thus, it was applied to construct a dual amplified "signal-on" mercury ion (Hg(2+)) sensor by the employment of nicking endonuclease (NEase)-assisted target recycling and rolling circle amplification (RCA) for signal amplification. Herein, a long G-rich sequence was generated by RCA process to capture abundant hemin on the electrode surface, and then a significantly amplified ECL signal of PTC-PEI was obtained. Based on dual signal amplification strategy, the devised sensor showed a linear range from 0.1pM to 0.1μΜ with a detection limit down to 33fM (S/N=3), and was successfully used in the direct detection of real water sample with high sensitivity and selectivity. Copyright © 2016 Elsevier B.V. All rights reserved.

SCRaMbLE generates designed combinatorial stochastic diversity in synthetic chromosomes.

PubMed

Shen, Yue; Stracquadanio, Giovanni; Wang, Yun; Yang, Kun; Mitchell, Leslie A; Xue, Yaxin; Cai, Yizhi; Chen, Tai; Dymond, Jessica S; Kang, Kang; Gong, Jianhui; Zeng, Xiaofan; Zhang, Yongfen; Li, Yingrui; Feng, Qiang; Xu, Xun; Wang, Jun; Wang, Jian; Yang, Huanming; Boeke, Jef D; Bader, Joel S

2016-01-01

Synthetic chromosome rearrangement and modification by loxP-mediated evolution (SCRaMbLE) generates combinatorial genomic diversity through rearrangements at designed recombinase sites. We applied SCRaMbLE to yeast synthetic chromosome arm synIXR (43 recombinase sites) and then used a computational pipeline to infer or unscramble the sequence of recombinations that created the observed genomes. Deep sequencing of 64 synIXR SCRaMbLE strains revealed 156 deletions, 89 inversions, 94 duplications, and 55 additional complex rearrangements; several duplications are consistent with a double rolling circle mechanism. Every SCRaMbLE strain was unique, validating the capability of SCRaMbLE to explore a diverse space of genomes. Rearrangements occurred exclusively at designed loxPsym sites, with no significant evidence for ectopic rearrangements or mutations involving synthetic regions, the 99% nonsynthetic nuclear genome, or the mitochondrial genome. Deletion frequencies identified genes required for viability or fast growth. Replacement of 3' UTR by non-UTR sequence had surprisingly little effect on fitness. SCRaMbLE generates genome diversity in designated regions, reveals fitness constraints, and should scale to simultaneous evolution of multiple synthetic chromosomes. © 2016 Shen et al.; Published by Cold Spring Harbor Laboratory Press.

Recent advances in signal amplification strategy based on oligonucleotide and nanomaterials for microRNA detection-a review.

PubMed

Chen, Ying-Xu; Huang, Ke-Jing; Niu, Ke-Xin

2018-01-15

MicroRNAs (MiRNAs) play multiple crucial regulating roles in cell which can regulate one third of protein-coding genes. MiRNAs participate in the developmental and physiological processes of human body, while their aberrant adjustment will be more likely to trigger diseases such as cancers, kidney disease, central nervous system diseases, cardiovascular diseases, diabetes, viral infections and so on. What's worse, for the detection of miRNAs, their small size, high sequence similarity, low abundance and difficult extraction from cells impose great challenges in the analysis. Hence, it's necessary to fabricate accurate and sensitive biosensing platform for miRNAs detection. Up to now, researchers have developed many signal-amplification strategies for miRNAs detection, including hybridization chain reaction, nuclease amplification, rolling circle amplification, catalyzed hairpin assembly amplification and nanomaterials based amplification. These methods are typical, feasible and frequently used. In this review, we retrospect recent advances in signal amplification strategies for detecting miRNAs and point out the pros and cons of them. Furthermore, further prospects and promising developments of the signal-amplification strategies for detecting miRNAs are proposed. Copyright © 2017 Elsevier B.V. All rights reserved.

Circular RNA biogenesis can proceed through an exon-containing lariat precursor.

PubMed

Barrett, Steven P; Wang, Peter L; Salzman, Julia

2015-06-09

Pervasive expression of circular RNA is a recently discovered feature of eukaryotic gene expression programs, yet its function remains largely unknown. The presumed biogenesis of these RNAs involves a non-canonical 'backsplicing' event. Recent studies in mammalian cell culture posit that backsplicing is facilitated by inverted repeats flanking the circularized exon(s). Although such sequence elements are common in mammals, they are rare in lower eukaryotes, making current models insufficient to describe circularization. Through systematic splice site mutagenesis and the identification of splicing intermediates, we show that circular RNA in Schizosaccharomyces pombe is generated through an exon-containing lariat precursor. Furthermore, we have performed high-throughput and comprehensive mutagenesis of a circle-forming exon, which enabled us to discover a systematic effect of exon length on RNA circularization. Our results uncover a mechanism for circular RNA biogenesis that may account for circularization in genes that lack noticeable flanking intronic secondary structure.

A hint of Poincaré dodecahedral topology in the WMAP first year sky map

NASA Astrophysics Data System (ADS)

Roukema, B. F.; Lew, B.; Cechowska, M.; Marecki, A.; Bajtlik, S.

2004-09-01

It has recently been suggested by Luminet et al. (\\cite{LumNat03}) that the WMAP data are better matched by a geometry in which the topology is that of a Poincaré dodecahedral model and the curvature is ``slightly'' spherical, rather than by an (effectively) infinite flat model. A general back-to-back matched circles analysis by Cornish et al. (\\cite{CSSK03}) for angular radii in the range 25-90 °, using a correlation statistic for signal detection, failed to support this. In this paper, a matched circles analysis specifically designed to detect dodecahedral patterns of matched circles is performed over angular radii in the range 1-40\\ddeg on the one-year WMAP data. Signal detection is attempted via a correlation statistic and an rms difference statistic. Extreme value distributions of these statistics are calculated for one orientation of the 36\\ddeg ``screw motion'' (Clifford translation) when matching circles, for the opposite screw motion, and for a zero (unphysical) rotation. The most correlated circles appear for circle radii of \\alpha =11 ± 1 \\ddeg, for the left-handed screw motion, but not for the right-handed one, nor for the zero rotation. The favoured six dodecahedral face centres in galactic coordinates are (\\lII,\\bII) ≈ (252\\ddeg,+65\\ddeg), (51\\ddeg,+51\\ddeg), (144\\ddeg,+38\\ddeg), (207\\ddeg,+10\\ddeg), (271\\ddeg,+3\\ddeg), (332\\ddeg,+25\\ddeg) and their opposites. The six pairs of circles independently each favour a circle angular radius of 11 ± 1\\ddeg. The temperature fluctuations along the matched circles are plotted and are clearly highly correlated. Whether or not these six circle pairs centred on dodecahedral faces match via a 36\\ddeg rotation only due to unexpected statistical properties of the WMAP ILC map, or whether they match due to global geometry, it is clear that the WMAP ILC map has some unusual statistical properties which mimic a potentially interesting cosmological signal.

[Comprehensive implementation of interprofessional quality circles regarding early prevention of childhood disadvantage in Baden Württemberg (Germany)].

PubMed

Siebolds, Marcus; Münzel, Brigitte; Müller, Roland; Häußermann, Sigrun; Paul, Mechthild; Kahl, Cornelia

2016-10-01

The integration of available early interventions and healthcare for families with children by practicing pediatricians has yet to be systematically established. For this reason, the Association of Statutory Health Insurance Physicians of Baden-Wuerttemberg established overarching, accredited, cross-system quality circles that serve to integrate all representatives of the healthcare system as well as child and youth welfare services. These quality circles are led by specially trained moderator tandems consisting of pediatricians and staff members from youth welfare services. The goal was to evaluate the endpoints of the regional implementation of cross-system quality circles for early interventions in the state of Baden-Wuerttemberg as well as the feasibility of establishing long-term training programs for cross-system moderator tandems. This was a noncontrolled, longitudinal study to prepare a yearly evaluation of the quality-circle assessments as well as to gather statistics on the training of the moderator tandems within the Association of Statutory Health Insurance Physicians of Baden-Wuerttemberg. A total of 59 moderator tandems were trained in nine separate training sessions within the project period from 2011 to 2015. Overall, 33 quality circles were founded. In 2015, 566 persons were participating in the respective circles. Over the course of the study between 26 and 33 of the 44 urban and rural districts in the state of Baden-Wuerttemberg had at least one quality circle dedicated to early interventions. Ten further circles are presently in the process of being founded; 29 moderators have yet to commence their activity or have withdrawn from the program. Between 59 and 81 % of the urban and rural districts implemented cross-system quality circles. The training of the moderator tandems proceeded without complications. Because of the dropout quota of the trained moderator tandems, systematic and continual training of new tandems proves to be necessary.

Models to support students’ understanding of measuring area of circles

NASA Astrophysics Data System (ADS)

Rejeki, S.; Putri, R. I. I.

2018-01-01

Many studies showed that enormous students got confused about the concepts of measuring area of circles. The main reason is because mathematics classroom practices emphasized on memorizing formulas rather than understanding concepts. Therefore, in this study, a set of learning activities were designed as an innovation in learning area measurement of circles. The activities involved two models namely grid paper and reshaping which are respectively as a means and a strategy to support students’ learning of area measurement of circles. Design research was used as the research approach to achieve the aim. Thirty-eight of 8th graders in Indonesia were involved in this study. In this study, together with the contextual problems, the grid paper and reshaping sectors, which used as the models in this learning, helped the students to gradually develop their understanding of the area measurement of circles. The grid papers plays important role in comparing and estimating areas. Whereas, the reshaping sectors might support students’ understanding of the circumference and the area measurement of circles. Those two models could be the tool for promoting the informal theory of area measurement. Besides, the whole activities gave important role on distinguishing the area and perimeter of circles.

Quality Circles: A Corporate Strategy Applied in a Student Services Setting.

ERIC Educational Resources Information Center

Steele, Brenton H.; And Others

1987-01-01

Discusses the historical and conceptual framework of quality circles, presents a brief case history of circles initiated by the University of Maryland Office of Admissions, and provides a summary of implications. Emphasizes implications for student affairs administrators. (Author/ABB)

Wind Factor Simulation Model: User’s Manual.

DTIC Science & Technology

1980-04-01

computer program documentation; com- puterized simulation; equivalent headwind technique; great circle; great circle distance; great circle equation ; great... equation of a great circle. Program listing and flow chart are included. iv UNCLASSIFIED SECURITY CLASSIFICATION OF THIS PAGE(WIh.n Date EnItrd) USER’S...THE EQUATOR . 336 C 337 NTRIFG = 0 338 C 339 C END OF FUNCTION ICONV I 1. RETURN TO MAIN PROGRAM . 340 C 42 341 RETURN 34? C 343 C 344 C 345 C * PART II

Normalized cDNA libraries

DOEpatents

Soares, Marcelo B.; Efstratiadis, Argiris

1997-01-01

This invention provides a method to normalize a directional cDNA library constructed in a vector that allows propagation in single-stranded circle form comprising: (a) propagating the directional cDNA library in single-stranded circles; (b) generating fragments complementary to the 3' noncoding sequence of the single-stranded circles in the library to produce partial duplexes; (c) purifying the partial duplexes; (d) melting and reassociating the purified partial duplexes to moderate Cot; and (e) purifying the unassociated single-stranded circles, thereby generating a normalized cDNA library.

Normalized cDNA libraries

DOEpatents

Soares, M.B.; Efstratiadis, A.

1997-06-10

This invention provides a method to normalize a directional cDNA library constructed in a vector that allows propagation in single-stranded circle form comprising: (a) propagating the directional cDNA library in single-stranded circles; (b) generating fragments complementary to the 3{prime} noncoding sequence of the single-stranded circles in the library to produce partial duplexes; (c) purifying the partial duplexes; (d) melting and reassociating the purified partial duplexes to moderate Cot; and (e) purifying the unassociated single-stranded circles, thereby generating a normalized cDNA library. 4 figs.

Developing learning trajectory on the circumference of a cycle with realistic mathematics education (RME)

NASA Astrophysics Data System (ADS)

Indriani, Novi; Julie, Hongki

2017-08-01

According Nuranisa, the students' difficulties on a lesson about the circumference of a circle were to understand the concept of what was the circumference of a circle and solve problems associated with the circumference of a circle [8]. According Nuranisa, this is because the teacher only gives a formula to find the circumference of a circle without helping students to construct the formula [8]. The purposes of this study were (1) to develop the hypothetical learning trajectory (HLT) for the cycle circumference material, (2) to describe the student results from the HLT implementation. The type of research used in this research was the design research developed by Gravemeijer and Cobb (2006). According Gravemeijer and Cobb, the design research was divided into three stages: (1) preparing for the experiment, (2) design experiments, and (3) retrospective analysis [6]. In this study, researchers developed the student learning trajectories which were help students to construct their knowledge about the understanding and how to calculate the circumference of a circle. The context used on the students' learning trajectory was sports and arts event. The learning trajectory has been tried out for 15 grade five students on the Budya Wacana elementary school in Yogyakarta. In this paper, researchers would describe how the learning trajectory traversed students to construct their knowledge about the understanding and how to calculate the circumference of the circle and the student thinking process on the understanding and how to calculate the circumference of a circle. The results showed that students could construct about the understanding of the circumference of a circle and how to calculate the circumference of a circle through the student learning trajectory.

The experience of meaning in circle dance

PubMed Central

Borges da Costa, Ana L.; Cox, Diane L.

2016-01-01

ABSTRACT Circle dance, which derives from the tradition of folk dances, is practised worldwide. This article explores the meanings participants attribute to it. In-depth interviews with 39 participants, teachers and coordinators of teacher training programmes from the circle dance network in the United Kingdom were undertaken. Applying a constructivist grounded theory approach, major categories, representing respectively the experiences of circle dance participants, teachers and coordinators, were developed. This article specifically focuses on the first major category, termed “I can't imagine life without it”, which relates to the experience of 22 dancers. From an occupational perspective, the study reveals how participants realise a sense of meaning and satisfaction through engagement in circle dance and the potential contribution of this occupation to well-being. PMID:27366111

Vicious Circles in Organizations.

ERIC Educational Resources Information Center

Masuch, Michael

1985-01-01

After examining some elementary notions of action theory and cybernetics, this article analyzes the dynamics, clustering, and survival chances of vicious circles. It argues that the action perspective implies that many structural suboptimalities of organizations are caused by vicious circles. Eleven figures and 105 references are provided. (DCS)

VIEW FROM EAST SIDE OF ELM DRIVE/BIRCH CIRCLE BLOCK, SHOWING ...

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

VIEW FROM EAST SIDE OF ELM DRIVE/BIRCH CIRCLE BLOCK, SHOWING SLOPING TOPOGRAPHY. VIEW FACING WEST. - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

The Exclusionary Circle Game: A Tool to Promote Critical Dialogue About HIV Stigma and Social Justice.

PubMed

Wong, Josephine Pui; Li, Alan Tai

2015-01-01

The Exclusionary Circle Game was a learning tool developed for an intervention study to address stigma associated with human immunodeficiency virus (HIV) infection and social exclusion. The objectives of The Exclusionary Circle Game were to enhance collective resonance and empathy, promote critical reflection and dialogue, and motivate collective action to address social exclusion. The game began with all participants being inside a circle. Each participant was randomly given one color-coded card. Each card color represented a character with a specific lived experience associated with racism, patriarchy, homophobia, transphobia, HIV stigma, and so on. Participants holding a marginalized status card were asked to leave the circle in sequence and go to designated spaces. Eventually, only one half of the participants were left in the circle. Participants then debriefed about their experiences within the entire group. The game has been used, beyond the intervention study, at research conferences with positive feedback. In this article, we detail the processes, strengths, and possibility of using this game for empowerment education.

Designing worked examples for learning tangent lines to circles

NASA Astrophysics Data System (ADS)

Retnowati, E.; Marissa

2018-03-01

Geometry is a branch of mathematics that deals with shape and space, including the circle. A difficult topic in the circle may be the tangent line to circle. This is considered a complex material since students have to simultaneously apply several principles to solve the problems, these are the property of circle, definition of the tangent, measurement and Pythagorean theorem. This paper discusses designs of worked examples for learning tangent line to circles and how to apply this design to an effective and efficient instructional activity. When students do not have sufficient prior knowledge, solving tangent problems might be clumsy, and as a consequence, the problem-solving activity hinders learning. According to a Cognitive Load Theory, learning occurs when students can construct new knowledge based on the relevant knowledge previously learned. When the relevant knowledge is unavailable, providing students with the worked example is suggested. Worked example may reduce unproductive process during learning that causes extraneous cognitive load. Nevertheless, worked examples must be created in such a way facilitate learning.

Improvement of rolling 6 mm thin plates in plate rolling mill PT. Krakatau Posco

NASA Astrophysics Data System (ADS)

Pujiyanto, Hamdani

2017-01-01

A 6-mm thin plate is difficult to produce especially if the product requires wide size and high strength. Flatness is the main quality issue in rolling 6-mm plate using a 4-high reversing mill which use ±1100-mm work roll. Thus some methods are applied to overcome such issue in order to comply to customer quality requirement. Pre-rolling, rolling, and post-rolling conditions have to be considered comprehensively. Roll unit management will be the key factor before rolling condition. The roll unit itself has a significant impact on work roll crown wearness in relation with work roll intial crown and thermal crown. Work roll crown along with the modification of hydraulic gap control (HGC) could directly alter the flatness of the plate.

Polyamine Triglycerides: Synthesis and Study of Their Potential in Lubrication, Neutralization, and Sequestration.

PubMed

Harry-O'kuru, Rogers E; Biresaw, Girma; Murray, Rex E

2015-07-22

Renewable resources have evoked a new awakening in both scientific and industrial circles in the past decade. Vegetable oil is one category of renewables that is amenable as a source of new industrial products. Because the source feedstock, seeds, are environmentally friendly, the derivatized products from these at the end of their lifetime could also be benign when designed appropriately. Bioethanol and biodiesel are examples of biobased industrial products currently in the market place and have become resources for uplifting the rural economy. Biolubricants also are playing a more prominent role because they have become closely competitive with petroleum-based lubricants. These products are renewable because the crops from which the feedstuff for the biofuels and biolubricants are produced are grown annually in contrast to nonrenewable mineral sources. Added to their renewability is the inherent biodegradability of their end-use products after their useful lifetime. In a recent study of the lubricity characteristics of peracylated polyhydroxy milkweed oil, the derivatives were found to exhibit good oxidative stability as well as excellent antiwear properties. To further explore an expansion in the properties of such materials in lubrication and other applications, in this study the polyhydroxy (OH) moieties of derivatized milkweed triglycerides were replaced with -NHR groupings in the oil. In this process novel polyketo triglyceride intermediates leading to polyamine derivatives of the vegetable oil have been synthesized. The polyamine triglyceride markedly improved the stability of the parent oil to oxidative stress. It has also attenuated the extreme viscosity of the starting polyhydroxy oil to a more useful product that could be amenable for use as a lubricating agent, for example, hydraulic fluid. Both the polyketone and polyimine intermediates of the polyamine have chelating properties. The intermediates and the polyamine were characterized spectroscopically, tribologically, and rheologically for their intrinsic properties.

Expression of MicroRNA-146a and MicroRNA-155 in Placental Villi in Early- and Late-Onset Preeclampsia.

PubMed

Nizyaeva, N V; Kulikova, G V; Nagovitsyna, M N; Kan, N E; Prozorovskaya, K N; Shchegolev, A I; Sukhikh, G T

2017-07-01

We studied the expression of microRNA-146a and microRNA-155 in placental villi from 18 women (26-39 weeks of gestation) of reproductive age with early- or late-onset preeclampsia. The reference group consisted of women with physiological pregnancy and full-term gestation and with preterm birth after caesarian section on gestation week 26-31. MicroRNA-146a and microRNA-155 were detected by in situ hybridization with digoxigenin on paraffin sections. It was found that the expression of microRNA-146a in both syncytiotrophoblast of the intermediate villi and syncytial knots was lower at late-onset preeclampsia than at physiologic pregnancy of full-term period (p=0.037 and p=0.001 respectively). The expression of microRNA-155 in syncytiotrophoblast of intermediate placental villi in early-onset preeclampsia was higher than in group with preterm delivery (p=0.003). However, in syncytiotrophoblast of intermediate villi and in syncytial knots, the expression of microRNA-155 was lower at late-onset preeclampsia in comparison with full-term physiological pregnancy (p=0.005). In addition, the expression of microRNA-146a and microRNA-155 did not increase in the later terms in preeclampsia, while in the reference groups demonstrating gradual increase in the expression of these markers with increasing gestational age. Expression microRNA-146a and microRNA-155 little differed in early- and late-onset preeclampsia. These findings suggest that different variants of preeclampsia are probably characterized by common pathogenetic pathways. Damaged trophoblast cannot maintain of microRNAs synthesis at the required level, which determines the formation of a vicious circle in preeclampsia and further progression of the disease.

Comfortable synchronization of cyclic drawing movements with a metronome.

PubMed

Repp, Bruno H

2011-02-01

Continuous circle drawing is considered a paragon of emergent timing, whereas the timing of finger tapping is said to be event-based. Synchronization with a metronome, however, must to some extent be event-based for both types of movement. Because the target events in the movement trajectory are more poorly defined in circle drawing than in tapping, circle drawing shows more variable asynchronies with a metronome than does tapping. One factor that may have contributed to high variability in past studies is that circle size, drawing direction, and target point were prescribed and perhaps outside the comfort range. In the present study, participants were free to choose most comfortable settings of these parameters for two continuously drawn shapes, circles and infinity signs, while synchronizing with a regular or intermittently perturbed metronome at four different tempi. Results showed that preferred circle sizes were generally smaller than in previous studies but tended to increase as tempo decreased. Synchronization results were similar for circles and infinity signs, and similar to earlier results for circles drawn within a fixed template (Repp & Steinman, 2010). Comparison with tapping data still showed drawing to exhibit much greater variability and persistence of asynchronies as well as slower phase correction in response to phase shifts in the metronome. With comfort level ruled out as a factor, these differences can now be attributed more confidently to differences in event definition and/or movement dynamics. Copyright © 2010 Elsevier B.V. All rights reserved.

What Goes Around Can Come Around: An Unexpected Deleterious Effect of Using Mouse Running Wheels for Environmental Enrichment

PubMed Central

Leduc, Renee Y M; Rauw, Gail; Baker, Glen B; McDermid, Heather E

2017-01-01

Environmental enrichment items such as running wheels can promote the wellbeing of laboratory mice. Growing evidence suggests that wheel running simulates exercise effects in many mouse models of human conditions, but this activity also might change other aspects of mouse behavior. In this case study, we show that the presence of running wheels leads to pronounced and permanent circling behavior with route-tracing in a proportion of the male mice of a genetically distinct cohort. The genetic background of this cohort includes a mutation in Arhgap19, but genetic crosses showed that an unknown second-site mutation likely caused the induced circling behavior. Behavioral tests for inner-ear function indicated a normal sense of gravity in the circling mice. However, the levels of dopamine, serotonin, and some dopamine metabolites were lower in the brains of circling male mice than in mice of the same genetic background that were weaned without wheels. Circling was seen in both singly and socially housed male mice. The additional stress of fighting may have exacerbated the predisposition to circling in the socially housed animals. Singly and socially housed male mice without wheels did not circle. Our current findings highlight the importance and possibly confounding nature of the environmental and genetic background in mouse behavioral studies, given that the circling behavior and alterations in dopamine and serotonin levels in this mouse cohort occurred only when the male mice were housed with running wheels. PMID:28315651

A Roll, Fin, and Fin Controller Prediction Computer Program.

DTIC Science & Technology

1980-06-01

IERATI *EQ. 03 WRITE16920301 ROLL 365 365 3R1TE(G. 26311 ROLL 366 no 505 ImU - 1,NNU ROLL 36? 50S WRITE(G.2011 3U(I’U),OAWPU(1PU,SIGLCfINU) ROLL 360...ROLL DAMPING WILL BE ONE**/$ ROLL 642 2016 FORMAT (/jIX,*LONGCRESTEO SVECTRA AND COMPONENTS WILL SE PRINTED. ROLL 44S 2’) ROLL 444 2019 FORMAT (1/19

Comprehensibility of Englishes within ASEAN: A Synopsis of Results

ERIC Educational Resources Information Center

Wilang, Jeffrey Dawala; Teo, Adisa

2012-01-01

The purpose of this study is to measure the comprehensibility of the Expanding Circle nations' citizens, namely Burmese, Cambodians, Indonesians, Laotians, Thais and Vietnamese towards the Outer Circle Englishes, namely Bruneian English, Malaysian English. Philippine English and Singaporean English. Ten universities in the Expanding Circle that…

CONTROL FOR ROLLING MILL

DOEpatents

Shuck, A.B.; Shaw, W.C.

1961-06-20

A plutonium-rolling apparatus is patented that has two sets of feed rolls, shaping rolls between the feed rolls, and grippers beyond the feed rolls, which ready a workpiece for a new pass through the shaping rolls by angularly shifting the workpiece about its axis or transversely moving it on a line parallel to the axes of the shaping rolls. Actuation of each gripper for gripping or releasing the workpiece is produced by the relative positions assumed by the feed rolls adjacent to the gripper as the workpiece enters or leaves the feed rolls.

An experimental study for determining human discomfort response to roll vibration

NASA Technical Reports Server (NTRS)

Leatherwood, J. D.; Dempsey, T. K.; Clevenson, S. A.

1976-01-01

An experimental study using a passenger ride quality apparatus (PRQA) was conducted to determine the subjective reactions of passengers to roll vibrations. The data obtained illustrate the effect upon human comfort of several roll-vibration parameters: namely, roll acceleration level, roll frequency, and seat location (i.e., distance from axis of rotation). Results of an analysis of variance indicated that seat location had no effect on discomfort ratings of roll vibrations. The effect of roll acceleration level was significant, and discomfort ratings increased markedly with increasing roll acceleration level at all roll frequencies investigated. Of particular interest, is the fact that the relationship between discomfort ratings and roll acceleration level was linear in nature. The effect of roll frequency also was significant as was the interaction between roll acceleration level and roll frequency.

Conceptions and Representations: The Circle as an Example.

ERIC Educational Resources Information Center

Janvier, Claude

This paper, which addresses the issue of representation as an internal construct corresponding to an external abstract configuration, attempts to extend A. A. DiSessa's phenomenological primitives to mathematics (particularly to the notion of circle). Various acceptations of the word representation are examined, using the notion of a circle as an…

Exploring Writing Circles as Innovative, Collaborative Writing Structures with Teacher Candidates

ERIC Educational Resources Information Center

Roberts, Sherron Killingsworth; Blanch, Norine; Gurjar, Nandita

2017-01-01

Writing circles are "small groups... meeting regularly to share drafts, choose common writing topics, practice positive response, and in general, help each other become better writers" (Vopat, 2009, p. 6). In this exploratory study, writing circles were employed with elementary teacher candidates in hopes of enhancing their perceptions…

The Effect of Literature Circles on Text Analysis and Reading Desire

ERIC Educational Resources Information Center

Karatay, Halit

2017-01-01

In order to make teaching activities more appealing, different techniques and strategies have been constantly employed. This study utilized the strategy of "literature circles" to improve the text-analysis skills, reading desires, and interests of prospective teachers of Turkish. "Literature circles" was not chosen to be used…

Adjusting an electron beam for drilling

NASA Technical Reports Server (NTRS)

Childress, C. L.

1980-01-01

Reticle contains two concentric circles: inner circle insures beam circularity and outer circle is guide to prevent beam from cutting workpiece clamp. Precise measurement of beam and clamp are required with old reticle. New reticle speeds up electron-beam drilling process by eliminating need to rotate eyepiece to make measurements against reticle scale.

Participation and Gender in Circle-Time Situations in Preschool

ERIC Educational Resources Information Center

Emilson, Anette; Johansson, Eva

2013-01-01

This study sought to investigate participatory values in relation to gender, as expressed in interactions between teachers and children in circle-time situations in Swedish and Norwegian preschools. This paper reports evidence from three research questions: How is children's participation conditioned in circle-time situations? How are…

An Effective Time and Management Strategy in Quality Circles.

ERIC Educational Resources Information Center

Halverson, Don E.

Contending that participation in quality circles enhances effective time management by school administrators and teachers, this guide provides both a theoretical briefing and practical recommendations for better time management. A pre- posttest prefaces a review of basic concepts of quality circles with reference to the work of Abraham Maslow,…

Quality Circles in Higher Education: Quality, Satisfaction, and Climate.

ERIC Educational Resources Information Center

Kay, Carol; Healy, Margaret

The effect of quality circles at Iowa State University on absenteeism, performance evaluation, perceptions of the organization climate, job satisfaction, and perceived opportunities for professional and personal growth was measured in this study. The process of quality circles is designed to promote job fulfillment and organizational productivity…

VIEW OF THE OUTER RING OF CENTER CIRCLE, LOOKING NORTH. ...

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

VIEW OF THE OUTER RING OF CENTER CIRCLE, LOOKING NORTH. GRANITE COPING DEFINES THE SWAIN FAMILY PLOT, WHICH CONTAINS A CELTIC CROSS, ON WHICH THE CIRCLE REFERS TO ETERNAL LIFE, AND A RECLINING HUMAN FIGURE IN ETERNAL SLEEP - Woodlands Cemetery, 4000 Woodlands Avenue, Philadelphia, Philadelphia County, PA

Using Literature Circles to Enhance Student Knowledge of Nonfiction Text

ERIC Educational Resources Information Center

Whitworth, Amanda

2017-01-01

This mixed methods action research study explored how students reacted to using literature circles to enhance their knowledge and understanding of reading nonfiction text as compared to students using guided reading. This study showed a minimal improvement for students participating in the literature circle group in overall understanding of…

Literature Circles. ERIC Digest.

ERIC Educational Resources Information Center

Lin, Chia-Hui

The use of literature circles has been discussed in a variety of academic journals, conference papers, and workshops. Teachers at all grade levels use literature circles as a vehicle through which students learn to: think critically about literature; express their thoughts in oral and written forms; and better enjoy their literacy experiences.…

Developing Soft Skills Using "Literature Circles"

ERIC Educational Resources Information Center

Azmi, Mohd Nazri Bin Latiff

2013-01-01

This study investigates the impact of the implementation of "Literature Circles" in an Active Learning classroom in relations to developing soft skills among university students. The use of Literature Circles is a well-known strategy in teaching the students to be more creative, independent, and think out of the box. A group of…

Exploring Factors That Influence Quality Literature Circles

ERIC Educational Resources Information Center

Young, Chase; Mohr, Kathleen A. J.

2018-01-01

Research indicates that literature circles are an authentic means for literacy development that students typically enjoy. To better understand the potential value and to add to the research base regarding literature circles, this study, involving 17 fourth graders, explores factors that may influence the quality of literature discussions,…

Method for construction of normalized cDNA libraries

DOEpatents

Soares, Marcelo B.; Efstratiadis, Argiris

1996-01-01

This invention provides a method to normalize a directional cDNA library constructed in a vector that allows propagation in single-stranded circle form comprising: (a) propagating the directional cDNA library in single-stranded circles; (b) generating fragments complementary to the 3' noncoding sequence of the single-stranded circles in the library to produce partial duplexes; (c) purifying the partial duplexes; (d) melting and reassociating the purified partial duplexes to moderate Cot; and (e) purifying the unassociated single-stranded circles, thereby generating a normalized cDNA library.

Method for construction of normalized cDNA libraries

DOEpatents

Soares, M.B.; Efstratiadis, A.

1996-01-09

This invention provides a method to normalize a directional cDNA library constructed in a vector that allows propagation in single-stranded circle form. The method comprises: (a) propagating the directional cDNA library in single-stranded circles; (b) generating fragments complementary to the 3` noncoding sequence of the single-stranded circles in the library to produce partial duplexes; (c) purifying the partial duplexes; (d) melting and reassociating the purified partial duplexes to moderate Cot; and (e) purifying the unassociated single-stranded circles, thereby generating a normalized cDNA library. 4 figs.

Sister Circles as a Culturally Relevant Intervention for Anxious African American Women

PubMed Central

Neal-Barnett, Angela; Stadulis, Robert; Murray, Marsheena; Payne, Margaret Ralston; Thomas, Anisha; Salley, Bernadette B.

2011-01-01

Research on anxiety treatment with African American women reveals a need to develop interventions that address factors relevant to their lives. Such factors include feelings of isolation, multiple roles undertaken by Black women, and faith. A recurrent theme across treatment studies is the importance of having support from other Black women. Sister circles are support groups that build upon existing friendships, fictive kin networks, and the sense of community found among African Americans females. Sister circles appear to offer many of the components Black women desire in an anxiety intervention. In this article, we explore sister circles as an intervention for anxious African American women. Culturally-infused aspects from our sister circle work with middle-class African American women are presented. Further research is needed. PMID:22081747

Age-related interference from irrelevant distracters in visual feature search among heterogeneous distracters.

PubMed

Merrill, Edward C; Conners, Frances A

2013-08-01

We evaluated age-related variations in the influence of heterogeneous distracters during feature target. Participants in three age groups-6-year-old children, 9-year-old children, and young adults-completed three conditions of search. In a singleton search condition, participants searched for a circle among squares of the same color. In two feature mode search conditions, participants searched for a gray circle or a black circle among gray and black squares. Singleton search was performed at the same level of efficiency for all age groups. In contrast, the two feature mode search conditions yielded age-related performance differences in both conditions. Younger children exhibited a steeper slope than young adults when searching for a gray or black circle. Older children exhibited a steeper slope than young adults when searching for a gray circle but not when searching for a black circle. We concluded that these differences revealed age-related improvements in the relative abilities of adults and children to execute attentional control processes during visual search. In particular, it appears that children found it more difficult to maintain the goal of searching for a circle target than adults and were distracted by the presence of the irrelevant feature dimension of color. Published by Elsevier Inc.

Experimental and Theoretical Study on Minimum Achievable Foil Thickness during Asymmetric Rolling

PubMed Central

Tang, Delin; Liu, Xianghua; Song, Meng; Yu, Hailiang

2014-01-01

Parts produced by microforming are becoming ever smaller. Similarly, the foils required in micro-machines are becoming ever thinner. The asymmetric rolling technique is capable of producing foils that are thinner than those produced by the conventional rolling technique. The difference between asymmetric rolling and conventional rolling is the ‘cross-shear’ zone. However, the influence of the cross-shear zone on the minimum achievable foil thickness during asymmetric rolling is still uncertain. In this paper, we report experiments designed to understand this critical influencing factor on the minimum achievable thickness in asymmetric rolling. Results showed that the minimum achievable thickness of rolled foils produced by asymmetric rolling with a rolling speed ratio of 1.3 can be reduced to about 30% of that possible by conventional rolling technique. Furthermore, the minimum achievable thickness during asymmetric rolling could be correlated to the cross-shear ratio, which, in turn, could be related to the rolling speed ratio. From the experimental results, a formula to calculate the minimum achievable thickness was established, considering the parameters cross-shear ratio, friction coefficient, work roll radius, etc. in asymmetric rolling. PMID:25203265

Attractor-Based Obstructions to Growth in Homogeneous Cyclic Boolean Automata.

PubMed

Khan, Bilal; Cantor, Yuri; Dombrowski, Kirk

2015-11-01

We consider a synchronous Boolean organism consisting of N cells arranged in a circle, where each cell initially takes on an independently chosen Boolean value. During the lifetime of the organism, each cell updates its own value by responding to the presence (or absence) of diversity amongst its two neighbours' values. We show that if all cells eventually take a value of 0 (irrespective of their initial values) then the organism necessarily has a cell count that is a power of 2. In addition, the converse is also proved: if the number of cells in the organism is a proper power of 2, then no matter what the initial values of the cells are, eventually all cells take on a value of 0 and then cease to change further. We argue that such an absence of structure in the dynamical properties of the organism implies a lack of adaptiveness, and so is evolutionarily disadvantageous. It follows that as the organism doubles in size (say from m to 2m) it will necessarily encounter an intermediate size that is a proper power of 2, and suffers from low adaptiveness. Finally we show, through computational experiments, that one way an organism can grow to more than twice its size and still avoid passing through intermediate sizes that lack structural dynamics, is for the organism to depart from assumptions of homogeneity at the cellular level.

Attractor-Based Obstructions to Growth in Homogeneous Cyclic Boolean Automata

PubMed Central

Khan, Bilal; Cantor, Yuri; Dombrowski, Kirk

2016-01-01

We consider a synchronous Boolean organism consisting of N cells arranged in a circle, where each cell initially takes on an independently chosen Boolean value. During the lifetime of the organism, each cell updates its own value by responding to the presence (or absence) of diversity amongst its two neighbours’ values. We show that if all cells eventually take a value of 0 (irrespective of their initial values) then the organism necessarily has a cell count that is a power of 2. In addition, the converse is also proved: if the number of cells in the organism is a proper power of 2, then no matter what the initial values of the cells are, eventually all cells take on a value of 0 and then cease to change further. We argue that such an absence of structure in the dynamical properties of the organism implies a lack of adaptiveness, and so is evolutionarily disadvantageous. It follows that as the organism doubles in size (say from m to 2m) it will necessarily encounter an intermediate size that is a proper power of 2, and suffers from low adaptiveness. Finally we show, through computational experiments, that one way an organism can grow to more than twice its size and still avoid passing through intermediate sizes that lack structural dynamics, is for the organism to depart from assumptions of homogeneity at the cellular level. PMID:27660398

THE FORM AND STRUCTURE OF KINETOPLAST DNA OF CRITHIDIA

PubMed Central

Renger, Hartmut C.; Wolstenholme, David R.

1972-01-01

Cesium chloride centrifugation of each of the DNAs extracted from eight strains of Crithidia revealed a main band at ρ = 1.717 g/cm3 and a satellite band varying from ρ = 1.701 to 1.705 g/cm3 for the different strains By electron microscopy each DNA was shown to include circular molecules, 0.69–0.80 µ in mean contour length, and large, topologically two-dimensional masses of DNA in which the molecules appeared in the form of rosettes. DNA isolated from kinetoplast fractions of Crithidia acanthocephali was shown to consist of light satellite DNA and to be mainly in the form of large masses, 0.8 µ (mol wt = 1.54 x 106 daltons) circular molecules, and a few long, linear molecules. The results of experiments involving ultracentrifugation, heating, and quenching, sonication, and endodeoxyribonuclease digestion, combined with electron microscopy, are consistent with the following hypothesis. The large DNA masses are associations of 0.8 µ circles which are mainly covalently closed. The circles are held together in groups (the rosettes) of up to 46 by the topological interlocking of each circle with many other circles in the group. A group of circles is attached to an adjacent group by one or more circles, each interlocking with many circles of both groups. Each of the associations comprises, on the average, about 27,000 circles (total mol wt ≃ 41 x 109 daltons). A model is proposed for the in situ arrangement of the associations which takes into consideration their form and structure, and appearance in thin sections PMID:5040863

Flat panel detector-based cone beam computed tomography with a circle-plus-two-arcs data acquisition orbit: preliminary phantom study.

PubMed

Ning, Ruola; Tang, Xiangyang; Conover, David; Yu, Rongfeng

2003-07-01

Cone beam computed tomography (CBCT) has been investigated in the past two decades due to its potential advantages over a fan beam CT. These advantages include (a) great improvement in data acquisition efficiency, spatial resolution, and spatial resolution uniformity, (b) substantially better utilization of x-ray photons generated by the x-ray tube compared to a fan beam CT, and (c) significant advancement in clinical three-dimensional (3D) CT applications. However, most studies of CBCT in the past are focused on cone beam data acquisition theories and reconstruction algorithms. The recent development of x-ray flat panel detectors (FPD) has made CBCT imaging feasible and practical. This paper reports a newly built flat panel detector-based CBCT prototype scanner and presents the results of the preliminary evaluation of the prototype through a phantom study. The prototype consisted of an x-ray tube, a flat panel detector, a GE 8800 CT gantry, a patient table and a computer system. The prototype was constructed by modifying a GE 8800 CT gantry such that both a single-circle cone beam acquisition orbit and a circle-plus-two-arcs orbit can be achieved. With a circle-plus-two-arcs orbit, a complete set of cone beam projection data can be obtained, consisting of a set of circle projections and a set of arc projections. Using the prototype scanner, the set of circle projections were acquired by rotating the x-ray tube and the FPD together on the gantry, and the set of arc projections were obtained by tilting the gantry while the x-ray tube and detector were at the 12 and 6 o'clock positions, respectively. A filtered backprojection exact cone beam reconstruction algorithm based on a circle-plus-two-arcs orbit was used for cone beam reconstruction from both the circle and arc projections. The system was first characterized in terms of the linearity and dynamic range of the detector. Then the uniformity, spatial resolution and low contrast resolution were assessed using different phantoms mainly in the central plane of the cone beam reconstruction. Finally, the reconstruction accuracy of using the circle-plus-two-arcs orbit and its related filtered backprojection cone beam volume CT reconstruction algorithm was evaluated with a specially designed disk phantom. The results obtained using the new cone beam acquisition orbit and the related reconstruction algorithm were compared to those obtained using a single-circle cone beam geometry and Feldkamp's algorithm in terms of reconstruction accuracy. The results of the study demonstrate that the circle-plus-two-arcs cone beam orbit is achievable in practice. Also, the reconstruction accuracy of cone beam reconstruction is significantly improved with the circle-plus-two-arcs orbit and its related exact CB-FPB algorithm, as compared to using a single circle cone beam orbit and Feldkamp's algorithm.

Microstructural and mechanical responses to various rolling speeds determined in multi-pass break-down rolling of AZ31B alloy

NASA Astrophysics Data System (ADS)

Jia, Weitao; Tang, Yan; Ning, Fangkun; Le, Qichi; Cui, Jianzhong

2018-04-01

Different rolling operations of as-cast AZ31B alloy were performed under different rolling speed (18 ∼ 72 m min‑1) and rolling pass conditions at 400 °C. Microstructural studies, tensile testing and formability evaluation relevant to each rolling operation were investigated. For 1-pass rolling, coarse average grain size (CAGS) region gradually approached the center layer as the rolling speed increased. Moreover, twins, shear bands and coarse-grain structures were the dominant components in the microstructure of plates rolled at 18, 48 and 72 m min‑1, respectively, indicating the severe deformation inhomogeneity under the high reduction per pass condition. For 2-pass rolling and 4-pass rolling, dynamic recrystallization was observed to be well and CAGS region has substantially disappeared, indicating the significant improvement in deformation uniformity and further the grain homogenization under the conditions. Microstructure uniformity degree of 2-pass rolled plates did not vary much as the rolling speed varied. On this basis, shear band distribution dominated the deformation behavior during the uniaxial tension of the 2-pass rolled plates. However, microstructure uniformity accompanied by twin distribution played a leading role in stretching the 4-pass rolled plates.

Polygons and Their Circles

ERIC Educational Resources Information Center

Stephenson, Paul

2009-01-01

In order to find its circumference, Archimedes famously boxed the circle between two polygons. Ending the first of a series of articles (MT179) with an aside, Francis Lopez-Real reverses the situation to ask: Which polygons can be boxed between two circles? (The official term for such polygons is "bicentric".) The sides of these polygons are…

Empowerment of Children through Circle Time: Myth or Reality?

ERIC Educational Resources Information Center

Collins, Bernie

2013-01-01

The focus of this paper is circle time, a widely used method in primary schools in Ireland and elsewhere. It involves children sitting in a circle with their teacher using method-specific techniques and strategies for self-esteem enhancement, promoting positive relationships and development of social skills. Qualitative research was undertaken in…

78 FR 44119 - Circle Environmental #1 Superfund Site; Dawson, Terrell County, Georgia; Notice of Settlement

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-23

... ENVIRONMENTAL PROTECTION AGENCY [FRL-9837-3; CERCLA-04-2013-3760] Circle Environmental 1 Superfund... settlement with Walter G. Mercer, Jr. concerning the Circle Environmental 1 Superfund Site located in Dawson... methods: Internet: www.epa.gov/region4/superfund/programs/enforcement/enforcement.html U.S. Mail: U.S...

VIEW OF DATE DRIVE, FROM INTERSECTION WITH BIRCH CIRCLE, WITH ...

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

VIEW OF DATE DRIVE, FROM INTERSECTION WITH BIRCH CIRCLE, WITH FACILITY 809 ON LEFT, 816 ON RIGHT. NOTE THE MANY DATE PALMS. VIEW FACING NORTHWEST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

From Silence to a Whisper to Active Participation: Using Literature Circles with ELL Students

ERIC Educational Resources Information Center

Carrison, Catherine; Ernst-Slavit, Gisela

2005-01-01

This article discusses benefits of using literature circles with ELL students to strengthen literacy skills and student confidence. Highlighting one teacher's implementation of literature circles, the authors present a candid examination of areas of initial weakness and describe strategies used for improvements in subsequent "rounds." A discussion…

Comparing Interactions in Literature Circles in Both Online and in Class Discussions

ERIC Educational Resources Information Center

Skeen, Christel Ghrist

2014-01-01

Discourse analysis of literature circles can lead educators to understand the different types of interactions taking place as students talk about text. Social and academic interactions exist in both face-to-face and online discussions of reading material. This study examines two different settings of literature circles and compares interactions of…

College Students' Science Societies and Special-Interest Circles

ERIC Educational Resources Information Center

Ivanov, A.

2005-01-01

From the point of view of their age, student science societies and special-interest circles are among the most venerable forms of corporate association among students in colleges and universities. In this article, the author traces the formation of different societies and special-interest circles by college students in different universities in…

Integrating Literature Circles into a Cotaught Inclusive Classroom

ERIC Educational Resources Information Center

Whittaker, Catharine R.

2012-01-01

Literature circles or book clubs are small, heterogeneous groups of students who have chosen to read and discuss the same book together. The research on literature circles suggests that they hold great promise for increasing students' enjoyment of reading and honing their literacy skills. When evidence-based strategies are embedded into a…

75 FR 19369 - Certain Hot-Rolled Flat-Rolled Carbon Quality Steel Products from Brazil: Preliminary Results of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-14

...-Rolled Carbon Quality Steel Products from Brazil: Preliminary Results of Antidumping Duty Administrative... duty order on certain hot-rolled flat-rolled carbon quality steel products (hot-rolled steel) from... 1, 2008, through February 28, 2009. We preliminarily determine that the sale of hot-rolled steel...

Violence in the eye of adolescents: education intervention with Culture Circles.

PubMed

Brandão Neto, Waldemar; Silva, Marta Angélica Iossi; de Aquino, Jael Maria; de Lima, Luciane Soares; Monteiro, Estela Maria Leite Meirelles

2015-01-01

to apply the methodology of Culture Circles on adolescents as a strategy for health education of nurses in the construction of the collective knowledge of the thematic violence. action research type and qualitative study. Participants were 11 adolescents from a public school in Recife, PE, Brazil. Data production in Culture Circles included the participant observation with field diary, photographic recording and filming, as well as the photovoice technique. The analysis was performed by triangulating data in dialogue with the literature. it was shown that the problematizing action provided by the Culture Circle made possible to create situations in which adolescents felt invited to critically refl ect on the phenomenon of violence in all its complexity. the health education intervention, performed by Culture Circles, added learning and mutual growth subsidizing nursing care actions that excel at leadership and autonomy of adolescents.

Multimodal determination of Rayleigh dispersion and attenuation curves using the circle fit method

NASA Astrophysics Data System (ADS)

Verachtert, R.; Lombaert, G.; Degrande, G.

2018-03-01

This paper introduces the circle fit method for the determination of multi-modal Rayleigh dispersion and attenuation curves as part of a Multichannel Analysis of Surface Waves (MASW) experiment. The wave field is transformed to the frequency-wavenumber (fk) domain using a discretized Hankel transform. In a Nyquist plot of the fk-spectrum, displaying the imaginary part against the real part, the Rayleigh wave modes correspond to circles. The experimental Rayleigh dispersion and attenuation curves are derived from the angular sweep of the central angle of these circles. The method can also be applied to the analytical fk-spectrum of the Green's function of a layered half-space in order to compute dispersion and attenuation curves, as an alternative to solving an eigenvalue problem. A MASW experiment is subsequently simulated for a site with a regular velocity profile and a site with a soft layer trapped between two stiffer layers. The performance of the circle fit method to determine the dispersion and attenuation curves is compared with the peak picking method and the half-power bandwidth method. The circle fit method is found to be the most accurate and robust method for the determination of the dispersion curves. When determining attenuation curves, the circle fit method and half-power bandwidth method are accurate if the mode exhibits a sharp peak in the fk-spectrum. Furthermore, simulated and theoretical attenuation curves determined with the circle fit method agree very well. A similar correspondence is not obtained when using the half-power bandwidth method. Finally, the circle fit method is applied to measurement data obtained for a MASW experiment at a site in Heverlee, Belgium. In order to validate the soil profile obtained from the inversion procedure, force-velocity transfer functions were computed and found in good correspondence with the experimental transfer functions, especially in the frequency range between 5 and 80 Hz.

Guided discovery of the nine-point circle theorem and its proof

NASA Astrophysics Data System (ADS)

Buchbinder, Orly

2018-01-01

The nine-point circle theorem is one of the most beautiful and surprising theorems in Euclidean geometry. It establishes an existence of a circle passing through nine points, all of which are related to a single triangle. This paper describes a set of instructional activities that can help students discover the nine-point circle theorem through investigation in a dynamic geometry environment, and consequently prove it using a method of guided discovery. The paper concludes with a variety of suggestions for the ways in which the whole set of activities can be implemented in geometry classrooms.

Quality circles and their potential application to rural health care in Papua New Guinea.

PubMed

Cibulskis, R E; Edwards, K N

1993-06-01

A quality circle is a group of service providers who meet regularly to solve problems relating to the quality of their work. This is an example of bottom-up rather than top-down management which has found considerable success in the industries of the developed world. This article describes the principles which govern the operation of quality circles, the expected benefits and how best to introduce them. The problems relating to the provision of quality health care in rural areas and the potential application of the quality circle methodology are discussed.

75 FR 64246 - Certain Hot-Rolled Flat-Rolled Carbon-Quality Steel Products From Brazil: Correction to Notice of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-19

...-Rolled Carbon-Quality Steel Products From Brazil: Correction to Notice of Antidumping Duty Order AGENCY... certain hot-rolled flat-rolled carbon-quality steel products from Brazil. See Antidumping Duty Order: Certain Hot-Rolled Flat-Rolled Carbon-Quality Steel Products From Brazil, 67 FR 11093 (March 12, 2002...

The Gasket of Circles: A Fractal of Circular Nature

ERIC Educational Resources Information Center

Haggar, Fred; Kricic, Senida

2017-01-01

Subdividing an equilateral triangle into four congruent triangles, then doing likewise to each of the three non-central triangles, and then again and again, leads to the Sierpinski gasket, from which the chaos game originated. An analogous procedure is hereforth applied to a circle, where a subdivision consists of two pairs of inscribed circles,…

Influence of a Mathematics Teachers' Circle on Elementary Teachers' Use of Problem Solving

ERIC Educational Resources Information Center

Garner, Mary L.; Watson, Virginia; Rogers, Beth; Head, Catherine

2017-01-01

Math teachers' circles are a form of professional development that is recommended by the Conference Board of the Mathematical Sciences in their publication Mathematical Education of Teachers II (2012). However, little research has been published on how effective math teachers' circles are in advancing the mathematical knowledge of teachers and…

Author Correction: Quantum Landauer erasure with a molecular nanomagnet

NASA Astrophysics Data System (ADS)

Gaudenzi, R.; Burzurí, E.; Maegawa, S.; van der Zant, H. S. J.; Luis, F.

2018-06-01

In the version of this Letter originally published, the key to the green and open circles in Fig. 4 was reversed; it should have shown that the green circles correspond to `From χ versus T' and the open circles correspond to `From χ versus Hy'. This has now been corrected in all versions of the Letter.

Growing a Circle of Courage Culture: One School's Journey

ERIC Educational Resources Information Center

Espiner, Deborah; Guild, Diane

2010-01-01

Mt. Richmond Special School is the first Circle of Courage school in New Zealand. The school reflects the richness of the cultural and learning diversity found in many New Zealand schools. Located in the heart of South Auckland, the school's 130 students represent a wide range of ethnic backgrounds. The universal values in the Circle of Courage…

Quality Circles: How Effective Are They in Improving Employee Performance and Attitudes?

ERIC Educational Resources Information Center

Buch, Kimberly; Raban, Amiram

1990-01-01

Used a quasi-experimental design to assess the effect of a quality circle intervention on behavior and attitudes of 88 employees at a large Midwestern organization. Results provide mixed support for the purported ability of circles to improve work behavior with no change for absenteeism and productivity but positive change for quality of work.…

Dynamic Investigation of Triangles Inscribed in a Circle, Which Tend to an Equilateral Triangle

ERIC Educational Resources Information Center

Stupel, Moshe; Oxman, Victor; Sigler, Avi

2017-01-01

We present a geometrical investigation of the process of creating an infinite sequence of triangles inscribed in a circle, whose areas, perimeters and lengths of radii of the inscribed circles tend to a limit in a monotonous manner. First, using geometrical software, we investigate four theorems that represent interesting geometrical properties,…

D'Nealian Handwriting versus Circle-Stick Print.

ERIC Educational Resources Information Center

Thurber, Donald N.

This paper argues against teaching children to make letters using circle-stick writing. It contends that the circle-stick method requires continued pen/pencil lifts hindering rhythm or flow in the writing process and that there is little carry-over value into cursive writing as the two scripts are totally different. D'Nealian print, one type of…

Unit Circles and Inverse Trigonometric Functions

ERIC Educational Resources Information Center

Barrera, Azael

2014-01-01

Historical accounts of trigonometry refer to the works of many Indian and Arab astronomers on the origin of the trigonometric functions as we know them now, in particular Abu al-Wafa (ca. 980 CE), who determined and named all known trigonometric functions from segments constructed on a regular circle and later on a unit circle (Moussa 2011;…

49 CFR 393.134 - What are the rules for securing roll-on/roll-off or hook lift containers?

Code of Federal Regulations, 2011 CFR

2011-10-01

... or hook lift containers? 393.134 Section 393.134 Transportation Other Regulations Relating to... for securing roll-on/roll-off or hook lift containers? (a) Applicability. The rules in this section apply to the transportation of roll-on/roll-off or hook lift containers. (b) Securement of a roll-on...

49 CFR 393.134 - What are the rules for securing roll-on/roll-off or hook lift containers?

Code of Federal Regulations, 2010 CFR

2010-10-01

... or hook lift containers? 393.134 Section 393.134 Transportation Other Regulations Relating to... for securing roll-on/roll-off or hook lift containers? (a) Applicability. The rules in this section apply to the transportation of roll-on/roll-off or hook lift containers. (b) Securement of a roll-on...

Rolling-Element Bearings

NASA Technical Reports Server (NTRS)

Hamrock, B. J.; Anderson, W. J.

1983-01-01

Rolling element bearings are a precision, yet simple, machine element of great utility. A brief history of rolling element bearings is reviewed and the type of rolling element bearings, their geometry and kinematics, as well as the materials they are made from and the manufacturing processes they involve are described. Unloaded and unlubricated rolling element bearings, loaded but unlubricated rolling element bearings and loaded and lubricated rolling element bearings are considered. The recognition and understanding of elastohydrodynamic lubrication covered, represents one of the major development in rolling element bearings.

Computer-aided analysis and design of the shape rolling process for producing turbine engine airfoils

NASA Technical Reports Server (NTRS)

Lahoti, G. D.; Akgerman, N.; Altan, T.

1978-01-01

Mild steel (AISI 1018) was selected as model cold-rolling material and Ti-6Al-4V and INCONEL 718 were selected as typical hot-rolling and cold-rolling alloys, respectively. The flow stress and workability of these alloys were characterized and friction factor at the roll/workpiece interface was determined at their respective working conditions by conducting ring tests. Computer-aided mathematical models for predicting metal flow and stresses, and for simulating the shape-rolling process were developed. These models utilize the upper-bound and the slab methods of analysis, and are capable of predicting the lateral spread, roll-separating force, roll torque and local stresses, strains and strain rates. This computer-aided design (CAD) system is also capable of simulating the actual rolling process and thereby designing roll-pass schedule in rolling of an airfoil or similar shape. The predictions from the CAD system were verified with respect to cold rolling of mild steel plates. The system is being applied to cold and hot isothermal rolling of an airfoil shape, and will be verified with respect to laboratory experiments under controlled conditions.

Optical Coherence Tomography Scan Circle Location and Mean Retinal Nerve Fiber Layer Measurement Variability

PubMed Central

Gabriele, Michelle L.; Ishikawa, Hiroshi; Wollstein, Gadi; Bilonick, Richard A.; Townsend, Kelly A.; Kagemann, Larry; Wojtkowski, Maciej; Srinivasan, Vivek J.; Fujimoto, James G.; Duker, Jay S.; Schuman, Joel S.

2009-01-01

PURPOSE To investigate the effect on optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) thickness measurements of varying the standard 3.4-mm-diameter circle location. METHODS The optic nerve head (ONH) region of 17 eyes of 17 healthy subjects was imaged with high-speed, ultrahigh-resolution OCT (hsUHR-OCT; 501 × 180 axial scans covering a 6 × 6-mm area; scan time, 3.84 seconds) for a comprehensive sampling. This method allows for systematic simulation of the variable circle placement effect. RNFL thickness was measured on this three-dimensional dataset by using a custom-designed software program. RNFL thickness was resampled along a 3.4-mm-diameter circle centered on the ONH, then along 3.4-mm circles shifted horizontally (x-shift), vertically (y-shift) and diagonally up to ±500 µm (at 100-µm intervals). Linear mixed-effects models were used to determine RNFL thickness as a function of the scan circle shift. A model for the distance between the two thickest measurements along the RNFL thickness circular profile (peak distance) was also calculated. RESULTS RNFL thickness tended to decrease with both positive and negative x- and y-shifts. The range of shifts that caused a decrease greater than the variability inherent to the commercial device was greater in both nasal and temporal quadrants than in the superior and inferior ones. The model for peak distance demonstrated that as the scan moves nasally, the RNFL peak distance increases, and as the circle moves temporally, the distance decreases. Vertical shifts had a minimal effect on peak distance. CONCLUSIONS The location of the OCT scan circle affects RNFL thickness measurements. Accurate registration of OCT scans is essential for measurement reproducibility and longitudinal examination (ClinicalTrials.gov number, NCT00286637). PMID:18515577

Synthesis of boron nitride coatings on quartz fibers: Thickness control and mechanism research

NASA Astrophysics Data System (ADS)

Zheng, Yu; Wang, Shubin

2011-10-01

Boron nitride (BN) coatings were successfully synthesized on quartz fibers by dip-coating in boric acid and urea solutions at 700 °C. The SEM micrographs indicated that the quartz fibers were fully covered by coatings with smooth surface. The XRD, FT-IR, XPS spectra and HR-TEM results showed that the composition of the coatings which combined closely with the quartz fibers was polycrystalline h-BN. By changing the dip circles, the coating thickness was well controlled. The thicknesses of samples dipped less than six circles increased linearly with dipping-circles; and the increment of coating thickness would slow down when the fibers were dipped 10 circles. After being dipped for 10 circles, the thickness was about 300 nm. The coating thickness was also established by calculation and the calculated results were consistent with the results measured by micrograph.

Inflationary dynamics with a smooth slow-roll to constant-roll era transition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Odintsov, S.D.; Oikonomou, V.K., E-mail: odintsov@ieec.uab.es, E-mail: v.k.oikonomou1979@gmail.com

In this paper we investigate the implications of having a varying second slow-roll index on the canonical scalar field inflationary dynamics. We shall be interested in cases that the second slow-roll can take small values and correspondingly large values, for limiting cases of the function that quantifies the variation of the second slow-roll index. As we demonstrate, this can naturally introduce a smooth transition between slow-roll and constant-roll eras. We discuss the theoretical implications of the mechanism we introduce and we use various illustrative examples in order to better understand the new features that the varying second slow-roll index introduces.more » In the examples we will present, the second slow-roll index has exponential dependence on the scalar field, and in one of these cases, the slow-roll era corresponds to a type of α-attractor inflation. Finally, we briefly discuss how the combination of slow-roll and constant-roll may lead to non-Gaussianities in the primordial perturbations.« less

Computer-aided analysis and design of the shape rolling process for producing turbine engine airfoils

NASA Technical Reports Server (NTRS)

Lahoti, G. D.; Akgerman, N.; Altan, T.

1978-01-01

Mild steel (AISI 1018) was selected as model cold rolling material and Ti-6A1-4V and Inconel 718 were selected as typical hot rolling and cold rolling alloys, respectively. The flow stress and workability of these alloys were characterized and friction factor at the roll/workpiece interface was determined at their respective working conditions by conducting ring tests. Computer-aided mathematical models for predicting metal flow and stresses, and for simulating the shape rolling process were developed. These models utilized the upper bound and the slab methods of analysis, and were capable of predicting the lateral spread, roll separating force, roll torque, and local stresses, strains and strain rates. This computer-aided design system was also capable of simulating the actual rolling process, and thereby designing the roll pass schedule in rolling of an airfoil or a similar shape.

AMS Fabric of a CRM in Hematite-Bearing Samples: Evidence of DRMs in Natural Red Beds

NASA Astrophysics Data System (ADS)

Kodama, K. P.

2002-12-01

Anisotropy of magnetic susceptibility (AMS) and anisotropy of isothermal remanence (AIR) in red sedimentary rocks both typically show a bedding parallel foliation with minimum axes clustered perpendicular to the bedding plane. Our studies have observed this type of magnetic fabric in red bed units that have a range of ages and come from widespread localities. These units include the Mississippian Mauch Chunk Formation from the Appalachians, the Triassic Passaic Formation from the Newark basin in Pennsylvania, the Cretaceous Kapusaliang Formation from the Tarim basin in China, and the early Mesozoic Kayenta and Chinle Formations from the Colorado Plateau in southwestern North America. Bedding parallel foliations are also observed in magnetite-bearing rocks that carry a depositional remanence (DRM), suggesting the possibility of a DRM in red beds, even though the conventional wisdom is that they carry a post-depositional chemical remanent magnetization (CRM). Before the typical magnetic fabric of red beds can be used to indicate their type of remanence, we must determine what the magnetic fabric of a CRM looks like. For this reason, I conducted a series of hematite-growth experiments following the procedures outlined by Stokking and Tauxe (1987). I grew hematite in the laboratory on stacks of glass-fiber filter papers and in slurries of quartz and kaolinite. The hematite was grown from a ferric nitrate solution heated to 95° C for 8 hours. The samples were then dehydrated in a vacuum at room temperature for approximately 38 hours. It was possible to thermally demagnetize the eight filter paper samples to 350° C, but the six kaolinite-quartz samples were grown in plastic sample cubes and could only be thermally demagnetized to 150° C, enough to remove the thermoviscous magnetization acquired by the samples during the heating at 95° C. The mean CRM acquired by the red-brown magnetic phase grown in the experiments was within its alpha-95 of the steeply inclined (inclination=60°) ambient magnetic field. The kaolinite-quartz samples had a very scattered remanence, probably due to the physical disturbance of the samples upon the initial application of the vacuum. In both the filter paper and kaolinite-quartz experiments the AMS fabric of the CRM-carrying grains was foliated with the maximum and intermediate principal axes defining a great circle that passes through the mean CRM direction and is moderately inclined (approximately 45°) to the horizontal. The moderately inclined great circle defined by the maximum-intermediate principal axes is quite distinct from the horizontal maximum-intermediate axes observed in the natural red bed samples, despite red bed characteristic remanences that range from nearly horizontal (Passaic, Chinle, Kayenta) to as steep as 30° (Mauch Chunk, Kapusaliang). This observation suggests that red bed characteristic remanence is typically a DRM, rather than a CRM. This has implications for interpreting red bed remanence since DRMs in hematite-bearing red beds may have large inclination errors.

Management of light absorption in extraordinary optical transmission based ultra-thin-film tandem solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mashooq, Kishwar; Talukder, Muhammad Anisuzzaman, E-mail: anis@eee.buet.ac.bd

2016-05-21

Although ultra-thin-film solar cells can be attractive in reducing the cost, they suffer from low absorption as the thickness of the active layer is usually much smaller than the wavelength of incident light. Different nano-photonic techniques, including plasmonic structures, are being explored to increase the light absorption in ultra-thin-film solar cells. More than one layer of active materials with different energy bandgaps can be used in tandem to increase the light absorption as well. However, due to different amount of light absorption in different active layers, photo-generated currents in different active layers will not be the same. The current mismatchmore » between the tandem layers makes them ineffective in increasing the efficiency. In this work, we investigate the light absorption properties of tandem solar cells with two ultra-thin active layers working as two subcells and a metal layer with periodically perforated holes in-between the two subcells. While the metal layer helps to overcome the current mismatch, the periodic holes increase the absorption of incident light by helping extraordinary optical transmission of the incident light from the top to the bottom subcell, and by coupling the incident light to plasmonic and photonic modes within ultra-thin active layers. We extensively study the effects of the geometry of holes in the intermediate metal layer on the light absorption properties of tandem solar cells with ultra-thin active layers. We also study how different metals in the intermediate layer affect the light absorption; how the geometry of holes in the intermediate layer affects the absorption when the active layer materials are changed; and how the intermediate metal layer affects the collection of photo-generated electron-hole pairs at the terminals. We find that in a solar cell with 6,6-phenyl C61-butyric acid methyl ester top subcell and copper indium gallium selenide bottom subcell, if the periodic holes in the metal layer are square or polygon, total absorption remains approximately the same. However, the total absorption suffers significantly if the holes are triangle. The transmission spectra of incident light into the bottom subcell, and hence the absorption, change significantly for square and circle holes if the active materials change to cadmium selenide (CdSe) and cadmium telluride (CdTe) in the top and bottom subcells, respectively. Although the intermediate metal layer may induce electron-hole pair recombination due to surface defects, the short-circuit current density of an ultra-thin plasmonic solar cell with an intermediate metal layer with two-dimensional hole array is >9% of that of a structure without the intermediate metal layer.« less

A Historical Note on the Proof of the Area of a Circle

ERIC Educational Resources Information Center

Wilamowsky, Yonah; Epstein, Sheldon; Dickman, Bernard

2011-01-01

Proofs that the area of a circle is nr[superscript 2] can be found in mathematical literature dating as far back as the time of the Greeks. The early proofs, e.g. Archimedes, involved dividing the circle into wedges and then fitting the wedges together in a way to approximate a rectangle. Later more sophisticated proofs relied on arguments…

The Revival of Research Circles: Meeting the Needs of Modern Aging and the Third Age

ERIC Educational Resources Information Center

Ostlund, Britt

2008-01-01

This article provides evidence that it is worthwhile to reconsider the traditional research circle method as a means of involving people in the third age in fulfilling their needs to participate in learning activities and make their voices heard. The findings are based on three cases of research circles consistently driven by the interests of the…

Providing a Full Circle of Support to Teachers in an Inclusive Elementary School

ERIC Educational Resources Information Center

Waldron, Nancy L.; Redd, Lacy

2011-01-01

Providing a full circle of support to teachers in an inclusive elementary school, the Newberry Elementary School (NES) principal and staff have worked for 5 years to ensure the inclusion of students with disabilities in general education classrooms. The authors would like to share their perceptions of how this full circle (the multiple systems) of…

Finding the Maximal Area of Bounded Polygons in a Circle

ERIC Educational Resources Information Center

Rokach, Arie

2005-01-01

The article deals with the area of polygons that are inscribed in a given circle. Naturally, the following question arises: Among all n-polygons that are inscribed in a given circle, which one has the biggest area? Intuitively, it may be guessed that is suitable for secondary students, and without any use id calculus, but only using very…

The Box and the Circle--Two Systems of Life: A Model for Understanding Native-Non-Native Issues.

ERIC Educational Resources Information Center

Derrick, Jann

Working as a family systems therapist with Native and non-Native families, the author observed two opposing social systems. Non-native families systems typify "The Box System," whereas native family systems portray "The Circle System." A few characteristics of the Circle System are: (1) a focus on life and peacefulness; (2) females and children…

Understanding Girls' Circle as an Intervention on Perceived Social Support, Body Image, Self-Efficacy, Locus of Control, and Self-Esteem

ERIC Educational Resources Information Center

Steese, Stephanie; Dollette, Maya; Phillips, William; Hossfeld, Elizabeth; Matthews, Gail; Taormina, Giovanna

2006-01-01

The Girls' Circle is a support group for adolescent girls developed by Beth Hossfeld and Giovanna Taormina as a unique program that addresses the needs of girls by focusing on increasing connections, building empathic skills, and developing resiliency. The present study evaluates the effectiveness of the Girls' Circle intervention on improving…

Implementing the patient circle. Call on patients to help improve perceptions of health care quality.

PubMed

Ostasiewski, P; Fugate, D L

1994-01-01

Adapting the quality-circle concept to a health care setting helped one hospital solve a problem and boosted its image among patients. The "patient circle" technique is one step health care providers can take toward delivering "total customer value," a quality perception that can mean the difference between surviving and thriving in the future.

DETAIL VIEW OF PIEDMONT AVENUE TRAFFIC CIRCLE AT INTERSECTION OF ...

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

DETAIL VIEW OF PIEDMONT AVENUE TRAFFIC CIRCLE AT INTERSECTION OF CHANNING WAY. SEEN FROM EAST SIDE OF CIRCLE LOOKING NORTH AT 2395 PIEDMONT, SIGMA PI HOUSE BY FREDERICK H. REIMERS, 1928. Photograph by Brian Grogan, July 8, 2007 - Piedmont Way & the Berkeley Property Tract, East of College Avenue between Dwight Way & U.C. Memorial Stadium, Berkeley, Alameda County, CA

Evolved Expendable Launch Vehicle (EELV)

DTIC Science & Technology

2015-12-15

FY13+ Phase I Buy Contractor: United Launch Services, LLC Contractor Location: 9501 East Panorama Circle Centennial , CO 80112 Contract Number...Contract Name: FY13+ Phase I Buy Contractor: United Launch Services, LLC Contractor Location: 9501 East Panorama Circle Centennial , CO 80112 Contract...FY12 EELV Launch Services (ELS5) Contractor: United Launch Services, LLC. Contractor Location: 9501 East Panorama Circle Centennial , CO 80112

Geometrical Solutions of Quadratic Equations.

ERIC Educational Resources Information Center

Grewal, A. S.; Godloza, L.

1999-01-01

Demonstrates that the equation of a circle (x-h)2 + (y-k)2 = r2 with center (h; k) and radius r reduces to a quadratic equation x2-2xh + (h2 + k2 -r2) = O at the intersection with the x-axis. Illustrates how to determine the center of a circle as well as a point on a circle. (Author/ASK)

Method for construction of normalized cDNA libraries

DOEpatents

Soares, Marcelo B.; Efstratiadis, Argiris

1998-01-01

This invention provides a method to normalize a directional cDNA library constructed in a vector that allows propagation in single-stranded circle form comprising: (a) propagating the directional cDNA library in single-stranded circles; (b) generating fragments complementary to the 3' noncoding sequence of the single-stranded circles in the library to produce partial duplexes; (c) purifying the partial duplexes; (d) melting and reassociating the purified partial duplexes to appropriate Cot; and (e) purifying the unassociated single-stranded circles, thereby generating a normalized cDNA library. This invention also provides normalized cDNA libraries generated by the above-described method and uses of the generated libraries.

Method for construction of normalized cDNA libraries

DOEpatents

Soares, M.B.; Efstratiadis, A.

1998-11-03

This invention provides a method to normalize a directional cDNA library constructed in a vector that allows propagation in single-stranded circle form comprising: (a) propagating the directional cDNA library in single-stranded circles; (b) generating fragments complementary to the 3` noncoding sequence of the single-stranded circles in the library to produce partial duplexes; (c) purifying the partial duplexes; (d) melting and reassociating the purified partial duplexes to appropriate Cot; and (e) purifying the unassociated single-stranded circles, thereby generating a normalized cDNA library. This invention also provides normalized cDNA libraries generated by the above-described method and uses of the generated libraries. 19 figs.

Sometimes area counts more than number.

PubMed

Hurewitz, Felicia; Gelman, Rochel; Schnitzer, Brian

2006-12-19

Using an interference paradigm, we show across three experiments that adults' order judgments of numbers, sizes, or combined area of dots in pairs of arrays occur spontaneously and automatically, but at different speeds and levels of accuracy. Experiment 1 used circles whose sizes varied between but not within arrays. Variation in circle size interfered with judgments of which array had more circles. Experiment 2 used displays in which circle size varied within and between arrays. Between-array differences in the amount of "circle stuff" (area occupied by circles) interfered with judgments of number. Experiment 3 examined whether variation in number also interferes with judgments of area. Interference between discrete and continuous stimulus dimensions occurred in both directions, although it was stronger from the continuous to the discrete than vice versa. These results bear on interpretations of studies with infants and preschoolers wherein subjects respond on the basis of continuous quantity rather than discrete quantity. In light of our results with adults, these findings do not license the conclusion that young children cannot represent discrete quantity. Absent data on attentional hierarchies and speed of processing, it is premature to conclude that infant and child quantity processes are fundamentally different from that of adults.

Walking straight into circles.

PubMed

Souman, Jan L; Frissen, Ilja; Sreenivasa, Manish N; Ernst, Marc O

2009-09-29

Common belief has it that people who get lost in unfamiliar terrain often end up walking in circles. Although uncorroborated by empirical data, this belief has widely permeated popular culture. Here, we tested the ability of humans to walk on a straight course through unfamiliar terrain in two different environments: a large forest area and the Sahara desert. Walking trajectories of several hours were captured via global positioning system, showing that participants repeatedly walked in circles when they could not see the sun. Conversely, when the sun was visible, participants sometimes veered from a straight course but did not walk in circles. We tested various explanations for this walking behavior by assessing the ability of people to maintain a fixed course while blindfolded. Under these conditions, participants walked in often surprisingly small circles (diameter < 20 m), though rarely in a systematic direction. These results rule out a general explanation in terms of biomechanical asymmetries or other general biases [1-6]. Instead, they suggest that veering from a straight course is the result of accumulating noise in the sensorimotor system, which, without an external directional reference to recalibrate the subjective straight ahead, may cause people to walk in circles.