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.

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.

Rolling-circle amplification under topological constraints

PubMed Central

Kuhn, Heiko; Demidov, Vadim V.; Frank-Kamenetskii, Maxim D.

2002-01-01

We have performed rolling-circle amplification (RCA) reactions on three DNA templates that differ distinctly in their topology: an unlinked DNA circle, a linked DNA circle within a pseudorotaxane-type structure and a linked DNA circle within a catenane. In the linked templates, the single-stranded circle (dubbed earring probe) is threaded, with the aid of two peptide nucleic acid openers, between the two strands of double-stranded DNA (dsDNA). We have found that the RCA efficiency of amplification was essentially unaffected when the linked templates were employed. By showing that the DNA catenane remains intact after RCA reactions, we prove that certain DNA polymerases can carry out the replicative synthesis under topological constraints allowing detection of several hundred copies of a dsDNA marker without DNA denaturation. Our finding may have practical implications in the area of DNA diagnostics. PMID:11788721

A pure DNA hydrogel with stable catalytic ability produced by one-step rolling circle amplification.

PubMed

Huang, Yishun; Xu, Wanlin; Liu, Guoyuan; Tian, Leilei

2017-03-09

A rolling-circle-amplification method was developed to produce DNA hydrogels with horseradish-peroxidase-like catalytic capability. The catalytic hydrogel exhibits highly improved stability at elevated temperatures or during a long-term storage. Integrated with glucose oxidase, the complex hydrogel can be applied to the sensitive and reliable detection of glucose.

Rolling circle amplification of metazoan mitochondrialgenomes

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

Simison, W. Brian; Lindberg, D.R.; Boore, J.L.

2005-07-31

Here we report the successful use of rolling circle amplification (RCA) for the amplification of complete metazoan mt genomes to make a product that is amenable to high-throughput genome sequencing techniques. The benefits of RCA over PCR are many and with further development and refinement of RCA, the sequencing of organellar genomics will require far less time and effort than current long PCR approaches.

Nanogrid rolling circle DNA sequencing

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

Church, George M.; Porreca, Gregory J.; Shendure, Jay

The present invention relates to methods for sequencing a polynucleotide immobilized on an array having a plurality of specific regions each having a defined diameter size, including synthesizing a concatemer of a polynucleotide by rolling circle amplification, wherein the concatemer has a cross-sectional diameter greater than the diameter of a specific region, immobilizing the concatemer to the specific region to make an immobilized concatemer, and sequencing the immobilized concatemer.

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)

Rolling Circle Amplification of Complete Nematode Mitochondrial Genomes

PubMed Central

Tang, Sha; Hyman, Bradley C.

2005-01-01

To enable investigation of nematode mitochondrial DNA evolution, methodology has been developed to amplify intact nematode mitochondrial genomes in preparative yields using a rolling circle replication strategy. Successful reactions were generated from whole cell template DNA prepared by alkaline lysis of the rhabditid nematode Caenorhabditis elegans and a mermithid nematode, Thaumamermis cosgrovei. These taxa, representing the two major nematode classes Chromodorea and Enoplea, maintain mitochondrial genomes of 13.8 kb and 20.0 kb, respectively. Efficient amplifications were conducted on template DNA isolated from individual or pooled nematodes that were alive or stored at -80°C. Unexpectedly, these experiments revealed that multiple T. cosgrovei mitochondrial DNA haplotypes are maintained in our local population. Rolling circle amplification products can be used as templates for standard PCR reactions with specific primers that target mitochondrial genes or for direct DNA sequencing. PMID:19262866

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.

Detection of Low-Copy-Number Genomic DNA Sequences in Individual Bacterial Cells by Using Peptide Nucleic Acid-Assisted Rolling-Circle Amplification and Fluorescence In Situ Hybridization▿ †

PubMed Central

Smolina, Irina; Lee, Charles; Frank-Kamenetskii, Maxim

2007-01-01

An approach is proposed for in situ detection of short signature DNA sequences present in single copies per bacterial genome. The site is locally opened by peptide nucleic acids, and a circular oligonucleotide is assembled. The amplicon generated by rolling circle amplification is detected by hybridization with fluorescently labeled decorator probes. PMID:17293504

Assign Roles to Get Literature Circles Rolling

ERIC Educational Resources Information Center

Curriculum Review, 2005

2005-01-01

This article briefly describes a role-playing exercise designed to break the ice in a classroom literature circle from The Ultimate Small-Group Reading How-To Book: Building Comprehension through SmallGroup Instruction, written by Gail Saunders-Smith. The members of a literature circle participate in the group discussion according to the…

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.

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.

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

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.

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.

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

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.

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."…

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…

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.

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…

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

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.

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

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

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.

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

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.

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

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

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.

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.

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.

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.

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.

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

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

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

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

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.

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.

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.

Specific functions of the Rep and Rep׳ proteins of porcine circovirus during copy-release and rolling-circle DNA replication.

PubMed

Cheung, Andrew K

2015-07-01

The roles of two porcine circovirus replication initiator proteins, Rep and Rep׳, in generating copy-release and rolling-circle DNA replication intermediates were determined. Rep uses the supercoiled closed-circular genome (ccc) to initiate leading-strand synthesis (identical to copy-release replication) and generates the single-stranded circular (ssc) genome from the displaced DNA strand. In the process, a minus-genome primer (MGP) necessary for complementary-strand synthesis, from ssc to ccc, is synthesized. Rep׳ cleaves the growing nascent-strand to regenerate the parent ccc molecule. In the process, a Rep׳-DNA hybrid containing the right palindromic sequence (at the origin of DNA replication) is generated. Analysis of the virus particle showed that it is composed of four components: ssc, MGP, capsid protein and a novel Rep-related protein (designated Protein-3). Copyright © 2015. Published by Elsevier Inc.

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.

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.

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.

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

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.

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.

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.

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,…

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

Electron microscopic studies of bacteriophage M13 DNA replication. [Escherichia coli

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

Allison, D.P.; Ganesan, A.T.; Olson, A.C.

Intracellular forms of M13 phage DNA isolated after infection of Escherichia coli with wild-type phage have been studied by electron microscopy and ultracentrifugation. The data indicate the involvement of rolling-circle intermediates in single-stranded DNA synthesis. In addition to single-stranded, circular DNA, we observed covalently closed and nicked replicative-form (RF) DNAs, dimer RF DNAs, concatenated RF DNAs, RF DNAs with single-stranded tails (sigma, rolling circles), and, occasionally, RF DNAs with theta structures. The tails in sigma molecules are always single stranded and are never longer than the DNA from mature phage; the proportion of sigma to other RF molecules does notmore » change significantly with time after infection. The origin of single-stranded DNA synthesis has been mapped by electron microscopy at a unique location on RF DNA by use of partial denaturation mapping and restriction endonuclease digestion. This location is between gene IV and gene II, and synthesis proceeds in a counterclockwise direction on the conventional genetic map.« less

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

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

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.

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

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.

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.

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

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.

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.

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.

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

DNA forms of the geminivirus African cassava mosaic virus consistent with a rolling circle mechanism of replication.

PubMed Central

Saunders, K; Lucy, A; Stanley, J

1991-01-01

We have analysed DNA from African cassava mosaic virus (ACMV)-infected Nicotiana benthamiana by two-dimensional agarose gel electrophoresis and detected ACMV-specific DNAs by blot-hybridisation. ACMV DNA forms including the previously characterised single-stranded, open-circular, linear and supercoiled DNAs along with five previously uncharacterised heterogeneous DNAs (H1-H5) were resolved. The heterogeneous DNAs were characterised by their chromatographic properties on BND-cellulose and their ability to hybridise to strand-specific and double-stranded probes. The data suggest a rolling circle mechanism of DNA replication, based on the sizes and strand specificity of the heterogeneous single-stranded DNA forms and their electrophoretic properties in relation to genome length single-stranded DNAs. Second-strand synthesis on a single-stranded virus-sense template is evident from the position of heterogeneous subgenomic complementary-sense DNA (H3) associated with genome-length virus-sense template (VT) DNA. The position of heterogeneous virus-sense DNA (H5), ranging in size from one to two genome lengths, is consistent with its association with genome-length complementary-sense template (CT) DNA, reflecting virus-sense strand displacement during replication from a double-stranded intermediate. The absence of subgenomic complementary-sense DNA associated with the displaced virus-sense strand suggests that replication proceeds via an obligate single-stranded intermediate. The other species of heterogeneous DNAs comprised concatemeric single-stranded virus-sense DNA (H4), and double-stranded or partially single-stranded DNA (H1 and H2). Images PMID:2041773

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.

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.

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.

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.

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)

Replicative intermediates of porcine circovirus in animal tissue cultured cells or in bacteria undergoing copy-release replication

USDA-ARS?s Scientific Manuscript database

Porcine circovirus (PCV) has been assumed to replicate its genome via the rolling-circle replication (RCR) mechanism because it encodes a Rep protein that contains several amino acid motifs commonly found in other RCR biological systems. Two proteins, Rep and Rep', are essential for PCV DNA replicat...

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.

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.

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.

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.

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.

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

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.

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

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.

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

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.

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

DNA Replication During Conjugal Transfer of R1162

DTIC Science & Technology

2002-01-01

transport out of the cell. This idea is stimulated by the similarity between the intermediates of single-stranded phage DNA replication and conjugative...the tra gene clusters ( Miele et al., 1991). The protein is not required for replication of the plasmid, and it seems to be dispensable for transfer...donor, in order to reattach to the transport mechanism prior to the start of a new round of transfer. Rolling circle replication itself might also be

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

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.

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.

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

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.

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.

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.

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.

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

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

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

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.

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.

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

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

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

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

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.

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

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.

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.

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.

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.

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.

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.

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.

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…

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.

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

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.

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.

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.

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,…

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.

Graphene Nanoprobes for Real-Time Monitoring of Isothermal Nucleic Acid Amplification.

PubMed

Li, Fan; Liu, Xiaoguo; Zhao, Bin; Yan, Juan; Li, Qian; Aldalbahi, Ali; Shi, Jiye; Song, Shiping; Fan, Chunhai; Wang, Lihua

2017-05-10

Isothermal amplification is an efficient way to amplify DNA with high accuracy; however, the real-time monitoring for quantification analysis mostly relied on expensive and precisely designed probes. In the present study, a graphene oxide (GO)-based nanoprobe was used to real-time monitor the isothermal amplification process. The interaction between GO and different DNA structures was systematically investigated, including single-stranded DNA (ssDNA), double-stranded DNA (dsDNA), DNA 3-helix, and long rolling circle amplification (RCA) and hybridization chain reaction (HCR) products, which existed in one-, two-, and three-dimensional structures. It was found that the high rigid structures exhibited much lower affinity with GO than soft ssDNA, and generally the rigidity was dependent on the length of targets and the hybridization position with probe DNA. On the basis of these results, we successfully monitored HCR amplification process, RCA process, and the enzyme restriction of RCA products with GO nanoprobe; other applications including the detection of the assembly/disassembly of DNA 3-helix structures were also performed. Compared to the widely used end-point detection methods, the GO-based sensing platform is simple, sensitive, cost-effective, and especially in a real-time monitoring mode. We believe such studies can provide comprehensive understandings and evocation on design of GO-based biosensors for broad application in various fields.

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

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…

Orthonormal vector general polynomials derived from the Cartesian gradient of the orthonormal Zernike-based polynomials.

PubMed

Mafusire, Cosmas; Krüger, Tjaart P J

2018-06-01

The concept of orthonormal vector circle polynomials is revisited by deriving a set from the Cartesian gradient of Zernike polynomials in a unit circle using a matrix-based approach. The heart of this model is a closed-form matrix equation of the gradient of Zernike circle polynomials expressed as a linear combination of lower-order Zernike circle polynomials related through a gradient matrix. This is a sparse matrix whose elements are two-dimensional standard basis transverse Euclidean vectors. Using the outer product form of the Cholesky decomposition, the gradient matrix is used to calculate a new matrix, which we used to express the Cartesian gradient of the Zernike circle polynomials as a linear combination of orthonormal vector circle polynomials. Since this new matrix is singular, the orthonormal vector polynomials are recovered by reducing the matrix to its row echelon form using the Gauss-Jordan elimination method. We extend the model to derive orthonormal vector general polynomials, which are orthonormal in a general pupil by performing a similarity transformation on the gradient matrix to give its equivalent in the general pupil. The outer form of the Gram-Schmidt procedure and the Gauss-Jordan elimination method are then applied to the general pupil to generate the orthonormal vector general polynomials from the gradient of the orthonormal Zernike-based polynomials. The performance of the model is demonstrated with a simulated wavefront in a square pupil inscribed in a unit circle.

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.

Great circle solution to polarization-based quantum communication (QC) in optical fiber

DOEpatents

Nordholt, Jane Elizabeth; Peterson, Charles Glen; Newell, Raymond Thorson; Hughes, Richard John

2016-03-15

Birefringence in optical fibers is compensated by applying polarization modulation at a receiver. Polarization modulation is applied so that a transmitted optical signal has states of polarization (SOPs) that are equally spaced on the Poincare sphere. Fiber birefringence encountered in propagation between a transmitter and a receiver rotates the great circle on the Poincare sphere that represents the polarization bases used for modulation. By adjusting received polarizations, polarization components of the received optical signal can be directed to corresponding detectors for decoding, regardless of the magnitude and orientation of the fiber birefringence. A transmitter can be configured to transmit in conjugate polarization bases whose SOPs can be represented as equidistant points on a great circle so that the received SOPs are mapped to equidistant points on a great circle and routed to corresponding detectors.

Highly sensitive MicroRNA 146a detection using a gold nanoparticle-based CTG repeat probing system and isothermal amplification.

PubMed

Le, Binh Huy; Seo, Young Jun

2018-01-25

We have developed a gold nanoparticle (AuNP)-based CTG repeat probing system displaying high quenching capability and combined it with isothermal amplification for the detection of miRNA 146a. This method of using a AuNP-based CTG repeat probing system with isothermal amplification allowed the highly sensitive (14 aM) and selective detection of miRNA 146a. A AuNP-based CTG repeat probing system having a hairpin structure and a dT F fluorophore exhibited highly efficient quenching because the CTG repeat-based stable hairpin structure imposed a close distance between the AuNP and the dT F residue. A small amount of miRNA 146a induced multiple copies of the CAG repeat sequence during rolling circle amplification; the AuNP-based CTG repeat probing system then bound to the complementary multiple-copy CAG repeat sequence, thereby inducing a structural change from a hairpin to a linear structure with amplified fluorescence. This AuNP-based CTG probing system combined with isothermal amplification could also discriminate target miRNA 146a from one- and two-base-mismatched miRNAs (ORN 1 and ORN 2, respectively). This simple AuNP-based CTG probing system, combined with isothermal amplification to induce a highly sensitive change in fluorescence, allows the detection of miRNA 146a with high sensitivity (14 aM) and selectivity. Copyright © 2017 Elsevier B.V. All rights reserved.

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.

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

Assessment of flat rolling theories for the use in a model-based controller for high-precision rolling applications

NASA Astrophysics Data System (ADS)

Stockert, Sven; Wehr, Matthias; Lohmar, Johannes; Abel, Dirk; Hirt, Gerhard

2017-10-01

In the electrical and medical industries the trend towards further miniaturization of devices is accompanied by the demand for smaller manufacturing tolerances. Such industries use a plentitude of small and narrow cold rolled metal strips with high thickness accuracy. Conventional rolling mills can hardly achieve further improvement of these tolerances. However, a model-based controller in combination with an additional piezoelectric actuator for high dynamic roll adjustment is expected to enable the production of the required metal strips with a thickness tolerance of +/-1 µm. The model-based controller has to be based on a rolling theory which can describe the rolling process very accurately. Additionally, the required computing time has to be low in order to predict the rolling process in real-time. In this work, four rolling theories from literature with different levels of complexity are tested for their suitability for the predictive controller. Rolling theories of von Kármán, Siebel, Bland & Ford and Alexander are implemented in Matlab and afterwards transferred to the real-time computer used for the controller. The prediction accuracy of these theories is validated using rolling trials with different thickness reduction and a comparison to the calculated results. Furthermore, the required computing time on the real-time computer is measured. Adequate results according the prediction accuracy can be achieved with the rolling theories developed by Bland & Ford and Alexander. A comparison of the computing time of those two theories reveals that Alexander's theory exceeds the sample rate of 1 kHz of the real-time computer.

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…

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.

Are we indeed what we eat? Street food consumption in the Market Circle area of Takoradi, Ghana.

PubMed

Hiamey, Stephen Edem; Amuquandoh, Francis Eric; Boison, Grace Aba

2013-01-01

The paper examines street foods consumption in the Market Circle of Sekondi-Takoradi, Ghana. The data used for the study were obtained from individuals who were either purchasing or consuming street foods in the Market Circle in August of 2011. The results revealed that the average consumer makes use of street foods six times in a week and there was a penchant for carbohydrate based foods over other types of street foods. Reasons including cost saving, convenience and eating on credit were noted to underlie the consumption of street foods in the area. Based on the findings, it was concluded that the high consumption of street foods in the Market Circle was for reasons other than nutrition and health. © The Author(s) 2015.

Fault Diagnosis for Centre Wear Fault of Roll Grinder Based on a Resonance Demodulation Scheme

NASA Astrophysics Data System (ADS)

Wang, Liming; Shao, Yimin; Yin, Lei; Yuan, Yilin; Liu, Jing

2017-05-01

Roll grinder is one of the important parts in the rolling machinery, and the grinding precision of roll surface has direct influence on the surface quality of steel strip. However, during the grinding process, the centre bears the gravity of the roll and alternating stress. Therefore, wear or spalling faults are easily observed on the centre, which will lead to an anomalous vibration of the roll grinder. In this study, a resonance demodulation scheme is proposed to detect the centre wear fault of roll grinder. Firstly, fast kurtogram method is employed to help select the sub-band filter parameters for optimal resonance demodulation. Further, the envelope spectrum are derived based on the filtered signal. Finally, two health indicators are designed to conduct the fault diagnosis for centre wear fault. The proposed scheme is assessed by analysing experimental data from a roll grinder of twenty-high rolling mill. The results show that the proposed scheme can effectively detect the centre wear fault of the roll grinder.

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.

REAR ELEVATION WITH BASE OF PALM TREE IN FOREGROUND. VIEW ...

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

REAR ELEVATION WITH BASE OF PALM TREE IN FOREGROUND. VIEW FACING NORTH/NORTHEAST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Three-Bedroom Single-Family Type 9, Birch Circle, Elm Drive, Elm Circle, and Date Drive, Pearl City, Honolulu County, HI

Noncanonical self-assembly of multifunctional DNA nanoflowers for biomedical applications.

PubMed

Zhu, Guizhi; Hu, Rong; Zhao, Zilong; Chen, Zhuo; Zhang, Xiaobing; Tan, Weihong

2013-11-06

DNA nanotechnology has been extensively explored to assemble various functional nanostructures for versatile applications. Mediated by Watson-Crick base-pairing, these DNA nanostructures have been conventionally assembled through hybridization of many short DNA building blocks. Here we report the noncanonical self-assembly of multifunctional DNA nanostructures, termed as nanoflowers (NFs), and the versatile biomedical applications. These NFs were assembled from long DNA building blocks generated via rolling circle replication (RCR) of a designer template. NF assembly was driven by liquid crystallization and dense packaging of building blocks, without relying on Watson-Crick base-pairing between DNA strands, thereby avoiding the otherwise conventional complicated DNA sequence design. NF sizes were readily tunable in a wide range, by simply adjusting such parameters as assembly time and template sequences. NFs were exceptionally resistant to nuclease degradation, denaturation, or dissociation at extremely low concentration, presumably resulting from the dense DNA packaging in NFs. The exceptional biostability is critical for biomedical applications. By rational design, NFs can be readily incorporated with myriad functional moieties. All these properties make NFs promising for versatile applications. As a proof-of-principle demonstration, in this study, NFs were integrated with aptamers, bioimaging agents, and drug loading sites, and the resultant multifunctional NFs were demonstrated for selective cancer cell recognition, bioimaging, and targeted anticancer drug delivery.

Noncanonical self-assembly of multifunctional DNA nanoflowers for biomedical applications

PubMed Central

Zhu, Guizhi; Hu, Rong; Zhao, Zilong; Chen, Zhuo; Zhang, Xiaobing; Tan, Weihong

2013-01-01

DNA nanotechnology has been extensively explored to assemble various functional nanostructures for versatile applications. Mediated by Watson-Crick base-pairing, these DNA nanostructures have been conventionally assembled through hybridization of many short DNA building blocks. Here we report the noncanonical self-assembly of multifunctional DNA nanostructures, termed as nanoflowers (NFs), and the versatile biomedical applications. These NFs were assembled from long DNA building blocks generated via Rolling Circle Replication (RCR) of a designer template. NF assembly was driven by liquid crystallization and dense packaging of building blocks, without relying on Watson-Crick base-pairing between DNA strands, thereby avoiding the otherwise conventional complicated DNA sequence design. NF sizes were readily tunable in a wide range, by simply adjusting such parameters as assembly time and template sequences. NFs were exceptionally resistant to nuclease degradation, denaturation, or dissociation at extremely low concentration, presumably resulting from the dense DNA packaging in NFs. The exceptional biostability is critical for biomedical applications. By rational design, NFs can be readily incorporated with myriad functional moieties. All these properties make NFs promising for versatile applications. As a proof-of-principle demonstration, in this study, NFs were integrated with aptamers, bioimaging agents, and drug loading sites, and the resultant multifunctional NFs were demonstrated for selective cancer cell recognition, bioimaging, and targeted anticancer drug delivery. PMID:24164620

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.

7. Front facade of main entrance, Awing, Minuteman circle looking ...

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

7. Front facade of main entrance, A-wing, Minuteman circle looking east - Offutt Air Force Base, Strategic Air Command Headquarters & Command Center, Headquarters Building, 901 SAC Boulevard, Bellevue, Sarpy County, NE

Analytic processing of distance.

PubMed

Dopkins, Stephen; Galyer, Darin

2018-01-01

How does a human observer extract from the distance between two frontal points the component corresponding to an axis of a rectangular reference frame? To find out we had participants classify pairs of small circles, varying on the horizontal and vertical axes of a computer screen, in terms of the horizontal distance between them. A response signal controlled response time. The error rate depended on the irrelevant vertical as well as the relevant horizontal distance between the test circles with the relevant distance effect being larger than the irrelevant distance effect. The results implied that the horizontal distance between the test circles was imperfectly extracted from the overall distance between them. The results supported an account, derived from the Exemplar Based Random Walk model (Nosofsky & Palmieri, 1997), under which distance classification is based on the overall distance between the test circles, with relevant distance being extracted from overall distance to the extent that the relevant and irrelevant axes are differentially weighted so as to reduce the contribution of irrelevant distance to overall distance. The results did not support an account, derived from the General Recognition Theory (Ashby & Maddox, 1994), under which distance classification is based on the relevant distance between the test circles, with the irrelevant distance effect arising because a test circle's perceived location on the relevant axis depends on its location on the irrelevant axis, and with relevant distance being extracted from overall distance to the extent that this dependency is absent. Copyright © 2017 Elsevier B.V. All rights reserved.

The arteries of the base of the brain in the N. American mink (Mustela vison (Brisson, 1756)).

PubMed

Gościcka, D; Stankiewicz, W; Szpinda, M

1995-01-01

110 brains of the N. American mink were studied for the arteries of the base of the brain, using the anatomical method and Digital Imaging Analysis. Two arterial circles were isolated: the larger cerebral circle (CC) and the smaller medullar circle (MC). These were connected by the basal artery of the brain. We found that in CC, its left part was larger, whereas in MC, it was the right part that was larger. Also, the capacity was larger in the caudal part of MC than in its rostral part.

Flexure-based Roll-to-roll Platform: A Practical Solution for Realizing Large-area Microcontact Printing

PubMed Central

Zhou, Xi; Xu, Huihua; Cheng, Jiyi; Zhao, Ni; Chen, Shih-Chi

2015-01-01

A continuous roll-to-roll microcontact printing (MCP) platform promises large-area nanoscale patterning with significantly improved throughput and a great variety of applications, e.g. precision patterning of metals, bio-molecules, colloidal nanocrystals, etc. Compared with nanoimprint lithography, MCP does not require a thermal imprinting step (which limits the speed and material choices), but instead, extreme precision with multi-axis positioning and misalignment correction capabilities for large area adaptation. In this work, we exploit a flexure-based mechanism that enables continuous MCP with 500 nm precision and 0.05 N force control. The fully automated roll-to-roll platform is coupled with a new backfilling MCP chemistry optimized for high-speed patterning of gold and silver. Gratings of 300, 400, 600 nm line-width at various locations on a 4-inch plastic substrate are fabricated at a speed of 60 cm/min. Our work represents the first example of roll-to-roll MCP with high reproducibility, wafer scale production capability at nanometer resolution. The precision roll-to-roll platform can be readily applied to other material systems. PMID:26037147

Spread prediction model of continuous steel tube based on BP neural network

NASA Astrophysics Data System (ADS)

Zhai, Jian-wei; Yu, Hui; Zou, Hai-bei; Wang, San-zhong; Liu, Li-gang

2017-07-01

According to the geometric pass of roll and technological parameters of three-roller continuous mandrel rolling mill in a factory, a finite element model is established to simulate the continuous rolling process of seamless steel tube, and the reliability of finite element model is verified by comparing with the simulation results and actual results of rolling force, wall thickness and outer diameter of the tube. The effect of roller reduction, roller rotation speed and blooming temperature on the spread rule is studied. Based on BP(Back Propagation) neural network technology, a spread prediction model of continuous rolling tube is established for training wall thickness coefficient and spread coefficient of the continuous rolling tube, and the rapid and accurate prediction of continuous rolling tube size is realized.

Definite Article Usage across Varieties of English

ERIC Educational Resources Information Center

Wahid, Ridwan

2013-01-01

This paper seeks to explore the extent of definite article usage variation in several varieties of English based on a classification of its usage types. An annotation scheme based on Hawkins and Prince was developed for this purpose. Using matching corpus data representing Inner Circle varieties and Outer Circle varieties, analysis was made on…

A Size-Distance Scaling Demonstration Based on the Holway-Boring Experiment

ERIC Educational Resources Information Center

Gallagher, Shawn P.; Hoefling, Crystal L.

2013-01-01

We explored size-distance scaling with a demonstration based on the classic Holway-Boring experiment. Undergraduate psychology majors estimated the sizes of two glowing paper circles under two conditions. In the first condition, the environment was dark and, with no depth cues available, participants ranked the circles according to their angular…

6. Threequarter view of Awing, building 500, from Minuteman Circle ...

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

6. Three-quarter view of A-wing, building 500, from Minuteman Circle looking northeast - Offutt Air Force Base, Strategic Air Command Headquarters & Command Center, Headquarters Building, 901 SAC Boulevard, Bellevue, Sarpy County, NE

A model for prediction of profile and flatness of hot and cold rolled flat products in four-high mills

NASA Astrophysics Data System (ADS)

Overhagen, Christian; Mauk, Paul Josef

2018-05-01

For flat rolled products, the thickness profile in the transversal direction is one of the most important product properties. For further processing, a defined crown of the product is necessary. In the rolling process, several mechanical and thermal influences interact with each other to form the strip shape at the roll gap exit. In the present analysis, a process model for rolling of strip and sheet is presented. The core feature of the process model is a two-dimensional stress distribution model based on von Karman's differential equation. Sub models for the mechanical influences of work roll flattening as well as work and backup roll deflection and the thermal influence of work roll expansion have been developed or extended. The two-dimensional stress distribution serves as an input parameter for the roll deformation models. For work roll flattening, a three-dimensional model based on the Boussinesq problem is adopted, while the work and backup roll deflection, including contact flattening is calculated by means of finite beam elements. The thermal work roll crown is calculated with help of an axisymmetric numerical solution of the heat equation for the work roll, considering azimuthal averaging for the boundary conditions at the work roll surface. Results are presented for hot rolling of a strip in a seven-stand finishing train of a hot strip mill, showing the calculated evolution of the strip profile. A variation of the strip profile from the first to the 20th rolled strip is shown. This variation is addressed to the progressive increase of work roll temperature during the first 20 strips. It is shown that a CVC® system can lead to improvements in strip profile and therefore flatness.

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.

iROLL: does 3-D radioguided occult lesion localization improve surgical management in early-stage breast cancer?

PubMed

Bluemel, Christina; Cramer, Andreas; Grossmann, Christoph; Kajdi, Georg W; Malzahn, Uwe; Lamp, Nora; Langen, Heinz-Jakob; Schmid, Jan; Buck, Andreas K; Grimminger, Hanns-Jörg; Herrmann, Ken

2015-10-01

To prospectively evaluate the feasibility of 3-D radioguided occult lesion localization (iROLL) and to compare iROLL with wire-guided localization (WGL) in patients with early-stage breast cancer undergoing breast-conserving surgery and sentinel lymph node biopsy (SLNB). WGL (standard procedure) and iROLL in combination with SLNB were performed in 31 women (mean age 65.1 ± 11.2 years) with early-stage breast cancer and clinically negative axillae. Patient comfort in respect of both methods was assessed using a ten point scale. SLNB and iROLL were guided by freehand SPECT (fhSPECT). The results of the novel 3-D image-based method were compared with those of WGL, ultrasound-based lesion localization, and histopathology. iROLL successfully detected the malignant primary and at least one sentinel lymph node in 97% of patients. In a single patient (3%), only iROLL, and not WGL, enabled lesion localization. The variability between fhSPECT and ultrasound-based depth localization of breast lesions was low (1.2 ± 1.4 mm). Clear margins were achieved in 81% of the patients; however, precise prediction of clear histopathological surgical margins was not feasible using iROLL. Patients rated iROLL as less painful than WGL with a pain score 0.8 ± 1.2 points (p < 0.01) lower than the score for iROLL. iROLL is a well-tolerated and feasible technique for localizing early-stage breast cancer in the course of breast-conserving surgery, and is a suitable replacement for WGL. As a single image-based procedure for localization of breast lesions and sentinel nodes, iROLL may improve the entire surgical procedure. However, no advantages of the image-guided procedure were found with regard to prediction of complete tumour resection.

View of Building No. 405 from Staff Circle, facing north ...

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

View of Building No. 405 from Staff Circle, facing north - MacDill Air Force Base, Bounded by City of Tampa North, Tampa Bay South, Old Tampa Bay West, & Hillsborough Bay East, Tampa, Hillsborough County, FL

Formula for the rms blur circle radius of Wolter telescope based on aberration theory

NASA Technical Reports Server (NTRS)

Shealy, David L.; Saha, Timo T.

1990-01-01

A formula for the rms blur circle for Wolter telescopes has been derived using the transverse ray aberration expressions of Saha (1985), Saha (1984), and Saha (1986). The resulting formula for the rms blur circle radius over an image plane and a formula for the surface of best focus based on third-, fifth-, and seventh-order aberration theory predict results in good agreement with exact ray tracing. It has also been shown that one of the two terms in the empirical formula of VanSpeybroeck and Chase (1972), for the rms blur circle radius of a Wolter I telescope can be justified by the aberration theory results. Numerical results are given comparing the rms blur radius and the surface of best focus vs the half-field angle computed by skew ray tracing and from analytical formulas for grazing incidence Wolter I-II telescopes and a normal incidence Cassegrain telescope.

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.

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.

Quantitative differential phase contrast imaging at high resolution with radially asymmetric illumination.

PubMed

Lin, Yu-Zi; Huang, Kuang-Yuh; Luo, Yuan

2018-06-15

Half-circle illumination-based differential phase contrast (DPC) microscopy has been utilized to recover phase images through a pair of images along multiple axes. Recently, the half-circle based DPC using 12-axis measurements significantly provides a circularly symmetric phase transfer function to improve accuracy for more stable phase recovery. Instead of using half-circle-based DPC, we propose a new scheme of DPC under radially asymmetric illumination to achieve circularly symmetric phase transfer function and enhance the accuracy of phase recovery in a more stable and efficient fashion. We present the design, implementation, and experimental image data demonstrating the ability of our method to obtain quantitative phase images of microspheres, as well as live fibroblast cell samples.

CircleBoard-Pro: Concrete manipulative-based learning cycle unit for learning geometry

NASA Astrophysics Data System (ADS)

Jamhari, Wongkia, Wararat

2018-01-01

Currently, a manipulative is commonly used in mathematics education as a supported tool for teaching and learning. With engaging natural interaction of a concrete manipulative and advantages of a learning cycle approach, we proposed the concrete manipulative-based learning cycle unit to promote mathematics learning. Our main objectives are to observe possibilities on the use of a concrete manipulative in learning geometry, and to assess students' understanding of a specific topic, angle properties in a circle, of secondary level students. To meet the first objective, the concrete manipulative, called CricleBoard-Pro, was designed. CircleBoard-Pro is built for easy to writing on or deleting from, accurate angle measurement, and flexible movement. Besides, learning activities and worksheets were created for helping students to learn angle properties in a circle. Twenty eighth graders on a lower secondary school in Indonesia were voluntarily involved to learn mathematics using CircleBoard-Pro with the designed learning activities and worksheets. We informally observed students' performance by focusing on criteria of using manipulative tools in learning mathematics while the learning activities were also observed in terms of whether they work and which step of activities need to be improved. The results of this part showed that CircleBoard-Pro complied the criteria of the use of the manipulative in learning mathematics. Nevertheless, parts of learning activities and worksheets need to be improved. Based on the results of the observation, CircleBoard-Pro, learning activities, and worksheets were merged together and became the CircleBoardPro embedded on 5E (Engage - Explore - Explain - Elaborate - Evaluate) learning cycle unit. Then, students understanding were assessed to reach the second objective. Six ninth graders from an Indonesian school in Thailand were recruited to participate in this study. Conceptual tests for both pre-and post-test, and semi-structured interview were used. Students' pre-and post-test answers were analyzed not only by descriptive statistics but also in qualitatively discussion. The dialogues between the interviewer and interviewees were transcribed and analyzed to find in-depth understanding. Finally, we can conclude that the participated students had better comprehension of angle properties in a circle even they could not perform proof by themselves. For further study, we will focus on how we can help students to develop their geometric thinking.

Rolling friction—models and experiment. An undergraduate student project

NASA Astrophysics Data System (ADS)

Vozdecký, L.; Bartoš, J.; Musilová, J.

2014-09-01

In this paper the rolling friction (rolling resistance) model is studied theoretically and experimentally in undergraduate level fundamental general physics courses. Rolling motions of a cylinder along horizontal or inclined planes are studied by simple experiments, measuring deformations of the underlay or of the rolling body. The rolling of a hard cylinder on a soft underlay as well as of a soft cylinder on a hard underlay is studied. The experimental data are treated by the open source software Tracker, appropriate for use at the undergraduate level of physics. Interpretation of results is based on elementary considerations comprehensible to university students—beginners. It appears that the commonly accepted model of rolling resistance based on the idea of a warp (little bulge) on the underlay in front of the rolling body does not correspond with experimental results even for the soft underlay and hard rolling body. The alternative model of the rolling resistance is suggested in agreement with experiment and the corresponding concept of the rolling resistance coefficient is presented. In addition to the obtained results we can conclude that the project can be used as a task for students in practical exercises of fundamental general physics undergraduate courses. Projects of similar type effectively contribute to the development of the physical thinking of students.

Crater Impacts on Vesta

NASA Image and Video Library

2012-05-10

This graphic shows the global distribution of craters that hit the giant asteroid Vesta, based on data from NASA Dawn mission. The yellow circles indicate craters of 2 miles or wider, with the size of the circles indicating the size of the crater.

Analysis of the symmetric configuration of the circle of Willis in a series of autopsied corpses.

PubMed

Stojanović, Nebojga; Stefanović, Ivica; Kostić, Aleksandar; Radisavejević, Misa; Stojanov, Dragan; Petrović, Sladjana

2015-04-01

The forming of the blood vessels network configuration at the base of the brain and interconnecting of blood vessels during the embryogenesis is directly related to the phylogenetic development of the brain and brain structures. A blood vessel configuration at the brain base, in the form of a ring or a hexagon, stands in direct relation to the perfusion needs of certain parts of the brain during its primary differentiation. The aim of this paper was to determine the incidence of certain blood vessel configurations at the base of the brain and understanding their symmetry or asymmetry. Analysis of the blood vessels at the base of the brain was performed on the autopsied subjects. The object of observation was the anterior segment of the circle of Willis consisting of C1- a. carotis interna (ICA), above a. communicaus posterior (PcoA), the segment A1 a. cerebri anterior (ACA) from a. carotis interna bifurcation to the a. communicans anterior (AcoA) and a communicans anterior itself, as well as the posterior segment consisting of PcoA and the segment P1--a. cerebri posterior (PCA) from the a. basilaris bifurcation to the PcoA. For the purpose of grouping the findings, the four basic configuration types of the circle of Willis were identified based on its symmetry or asymmetry. Type-A (symmetric circle of Willis), type-B (asymmetric circle of Willis' due to the unilateral hypoplastic A1-ACA); type-C (symmetric circle of Willis with bilateral symmetric changes on PcoA) and type-D (asymmetric circle of Willis due to the asymmetric changes on PcoA). Autosy was performed on 56 corpses. A total of 41 (73.2%) subjects were recorded with a symmetric configuration of the circle of Willis', of which 27 (48.2%) subjects had type A and 14 (25%) type C. The asymmetric configuration was present in 15 (26.8%) subjects, of whom 9 (16%) had type B and 6 (10.8%) subjects, of whom 9 (16%) had type B and 6 (10.8%) type D. The symmetric Willis group (73.2%) did not have a homogeneous finding that would fit into the schematic presentation of the symmetric type A and type C. A total of 17 (30.4%) findings were classified in this group of the so-called conditionally symmetric configurations. In all the cases, type B (16%) had unilaterally reduced diameter A1 and hyperplastic AcoA. The presence of asymmetric Willis configuration in 26.8% of the cases, which makes up more than one fourth, indicates that the asymmetric configurations do not represent a pathological form of connecting the blood vessels at the base of the brain, but rather one aspect of its adaptation. The forming of the basic types of configurations of the circle of Willis is associated with a tendency toward certain types of hemodynamic disorders and more frequent pathological changes in places of reduced resistance.

Study of helicopterroll control effectiveness criteria

NASA Technical Reports Server (NTRS)

Heffley, Robert K.; Bourne, Simon M.; Curtiss, Howard C., Jr.; Hindson, William S.; Hess, Ronald A.

1986-01-01

A study of helicopter roll control effectiveness based on closed-loop task performance measurement and modeling is presented. Roll control critieria are based on task margin, the excess of vehicle task performance capability over the pilot's task performance demand. Appropriate helicopter roll axis dynamic models are defined for use with analytic models for task performance. Both near-earth and up-and-away large-amplitude maneuvering phases are considered. The results of in-flight and moving-base simulation measurements are presented to support the roll control effectiveness criteria offered. This Volume contains the theoretical analysis, simulation results and criteria development.

A new measuring method for motion accuracy of 3-axis NC equipments based on composite trajectory of circle and non-circle

NASA Astrophysics Data System (ADS)

Yang, Fan; Du, Zhengchun; Yang, Jiangguo; Hong, Maisheng

2011-12-01

Geometric motion error measurement has been considered as an important task for accuracy enhancement and quality assurance of NC machine tools and CMMs. In consideration of the disadvantages of traditional measuring methods,a new measuring method for motion accuracy of 3-axis NC equipments based on composite trajectory including circle and non-circle(straight line and/or polygonal line) is proposed. The principles and techniques of the new measuring method are discussed in detail. 8 feasible measuring strategies based on different measuring groupings are summarized and optimized. The experiment of the most preferable strategy is carried out on the 3-axis CNC vertical machining center Cincinnati 750 Arrow by using cross grid encoder. The whole measuring time of 21 error components of the new method is cut down to 1-2 h because of easy installation, adjustment, operation and the characteristics of non-contact measurement. Result shows that the new method is suitable for `on machine" measurement and has good prospects of wide application.

An advanced dissymmetric rolling model for online regulation

NASA Astrophysics Data System (ADS)

Cao, Trong-Son

2017-10-01

Roll-bite model is employed to predict the rolling force, torque as well as to estimate the forward slip for preset or online regulation at industrial rolling mills. The rolling process is often dissymmetric in terms of work-rolls rotation speeds and diameters as well as the friction conditions at upper and lower contact surfaces between work-rolls and the strip. The roll-bite model thus must be able to account for these dissymmetries and in the same time has to be accurate and fast enough for online applications. In the present study, a new method, namely Adapted Discretization Slab Method (ADSM) is proposed to obtain a robust roll-bite model, which can take into account the aforementioned dissymmetries and has a very short response time, lower than one millisecond. This model is based on the slab method, with an adaptive discretization and a global Newton-Raphson procedure to improve the convergence speed. The model was validated by comparing with other dissymmetric models proposed in the literature, as well as Finite Element simulations and industrial pilot trials. Furthermore, back-calculation tool was also constructed for friction management for both offline and online applications. With very short CPU time, the ADSM-based model is thus attractive for all online applications, both for cold and hot rolling.

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.

The Effects of Activities Based on the Multiple Intelligence Theory of Students' Conceptual Learning and Their Retention: A Case of Circle and Cylinder

ERIC Educational Resources Information Center

Gurbuz, Ramazan; Birgin, Osman; Catlioglu, Hakan

2014-01-01

The purpose of this study was to investigate the effect of activities based on the Multiple Intelligence Theory (MIT) of seventh grade students' conceptual learning and their retention in two consecutive subjects, namely "The Circumference and the Area of a Circle" and "The Surface Area of the Vertical Cylinder". The…

[Data supporting quality circle management of inpatient depression treatment].

PubMed

Brand, S; Härter, M; Sitta, P; van Calker, D; Menke, R; Heindl, A; Herold, K; Kudling, R; Luckhaus, C; Rupprecht, U; Sanner, Dirk; Schmitz, D; Schramm, E; Berger, M; Gaebel, W; Schneider, F

2005-07-01

Several quality assurance initiatives in health care have been undertaken during the past years. The next step consists of systematically combining single initiatives in order to built up a strategic quality management. In a German multicenter study, the quality of inpatient depression treatment was measured in ten psychiatric hospitals. Half of the hospitals received comparative feedback on their individual results in comparison to the other hospitals (bench marking). Those bench markings were used by each hospital as a statistic basis for in-house quality work, to improve the quality of depression treatment. According to hospital differences concerning procedure and outcome, different goals were chosen. There were also differences with respect to structural characteristics, strategies, and outcome. The feedback from participants about data-based quality circles in general and the availability of bench-marking data was positive. The necessity of carefully choosing quality circle members and professional moderation became obvious. Data-based quality circles including bench-marking have proven to be useful for quality management in inpatient depression care.

Effective size of certain macroscopic quantum superpositions.

PubMed

Dür, Wolfgang; Simon, Christoph; Cirac, J Ignacio

2002-11-18

Several experiments and experimental proposals for the production of macroscopic superpositions naturally lead to states of the general form /phi(1)>( multiply sign in circle N)+/phi 2 >( multiply sign in circle N), where the number of subsystems N is very large, but the states of the individual subsystems have large overlap, // 2=1-epsilon 2. We propose two different methods for assigning an effective particle number to such states, using ideal Greenberger-Horne-Zeilinger states of the form /0>( multiply sign in circle n)+/1>( multiply sign in circle n) as a standard of comparison. The two methods are based on decoherence and on a distillation protocol, respectively. Both lead to an effective size n of the order of N epsilon 2.

A magnetic nanobead-based bioassay provides sensitive detection of single- and biplex bacterial DNA using a portable AC susceptometer

PubMed Central

Strömberg, Mattias; Zardán Gómez de la Torre, Teresa; Nilsson, Mats; Svedlindh, Peter; Strømme, Maria

2014-01-01

Bioassays relying on magnetic read-out using probe-tagged magnetic nanobeads are potential platforms for low-cost biodiagnostic devices for pathogen detection. For optimal assay performance it is crucial to apply an easy, efficient and robust bead-probe conjugation protocol. In this paper, sensitive (1.5 pM) singleplex detection of bacterial DNA sequences is demonstrated in a portable AC susceptometer by a magnetic nanobead-based bioassay principle; the volume-amplified magnetic nanobead detection assay (VAM-NDA). Two bead sizes, 100 and 250 nm, are investigated along with a highly efficient, rapid, robust, and stable conjugation chemistry relying on the avidin–biotin interaction for bead-probe attachment. Avidin-biotin conjugation gives easy control of the number of detection probes per bead; thus allowing for systematic investigation of the impact of varying the detection probe surface coverage upon bead immobilization in rolling circle amplified DNA-coils. The existence of an optimal surface coverage is discussed. Biplex VAM-NDA detection is for the first time demonstrated in the susceptometer: Semi-quantitative results are obtained and it is concluded that the concentration of DNA-coils in the incubation volume is of crucial importance for target quantification. The present findings bring the development of commercial biodiagnostic devices relying on the VAM–NDA further towards implementation in point-of-care and outpatient settings. PMID:24174315

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

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

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

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.

A Pilot Opinion Study of Lateral Control Requirements for Fighter-Type Aircraft

NASA Technical Reports Server (NTRS)

Creer, Brent Y.; Stewart, John D.; Merrick, Robert B.; Drinkwater, Fred J., III

1959-01-01

As part of a continuing NASA program of research on airplane handling qualities, a pilot opinion investigation has been made on the lateral control requirements of fighter aircraft flying in their combat speed range. The investigation was carried out using a stationary flight simulator and a moving flight simulator, and the flight simulator results were supplemented by research tests in actual flight. The flight simulator study was based on the presumption that the pilot rates the roll control of an airplane primarily on a single-degree-of-freedom basis; that is, control of angle of roll about the aircraft body axis being of first importance. From the assumption of a single degree of freedom system it follows that there are two fundamental parameters which govern the airplane roll response, namely the roll damping expressed as a time constant and roll control power in terms of roll acceleration. The simulator study resulted in a criterion in terms of these two parameters which defines satisfactory, unsatisfactory, and unacceptable roll performance from a pilot opinion standpoint. The moving simulator results were substantiated by the in-flight investigation. The derived criterion was compared with the roll performance criterion based upon wing tip helix angle and also with other roll performance concepts which currently influence the roll performance design of military fighter aircraft flying in their combat speed range.

Astrometric Discovery of GJ 164B

NASA Technical Reports Server (NTRS)

Pravdo, Steven H.; Shaklan, Stuart B.; Henry, Todd; Benedict, G. Fritz

2004-01-01

We discovered a low-mass companion to the M dwarf GJ 164 with the CCD-based imaging system of the Stellar Planet Survey astrometric program. The existence of GJ 164B was confirmed with Hubble Space Telescope NICMOS imaging observations. A high-dispersion spectral observation in V sets a lower limit of Deltam > 2.2 mag between the two components of the system. Based on our parallax value of 82 +/- 8 mas, we derive the following orbital parameters: P = 2.04 +/- 0.03 yr, a = 103 +/- 0.03, and M-total 0.265 +/- 0.020 M-circle dot. The component masses are M-A = 0.170 +/- 0.015 M-circle dot and M-B = 0.095 +/- 0/015 M-circle dot. Based on its mass, colors, and spectral properties, GJ 164B has spectral type M6-M8 V.

Implementation and verification of a four-probe motion error measurement system for a large-scale roll lathe used in hybrid manufacturing

NASA Astrophysics Data System (ADS)

Chen, Yuan-Liu; Niu, Zengyuan; Matsuura, Daiki; Lee, Jung Chul; Shimizu, Yuki; Gao, Wei; Oh, Jeong Seok; Park, Chun Hong

2017-10-01

In this paper, a four-probe measurement system is implemented and verified for the carriage slide motion error measurement of a large-scale roll lathe used in hybrid manufacturing where a laser machining probe and a diamond cutting tool are placed on two sides of a roll workpiece for manufacturing. The motion error of the carriage slide of the roll lathe is composed of two straightness motion error components and two parallelism motion error components in the vertical and horizontal planes. Four displacement measurement probes, which are mounted on the carriage slide with respect to four opposing sides of the roll workpiece, are employed for the measurement. Firstly, based on the reversal technique, the four probes are moved by the carriage slide to scan the roll workpiece before and after a 180-degree rotation of the roll workpiece. Taking into consideration the fact that the machining accuracy of the lathe is influenced by not only the carriage slide motion error but also the gravity deformation of the large-scale roll workpiece due to its heavy weight, the vertical motion error is thus characterized relating to the deformed axis of the roll workpiece. The horizontal straightness motion error can also be synchronously obtained based on the reversal technique. In addition, based on an error separation algorithm, the vertical and horizontal parallelism motion error components are identified by scanning the rotating roll workpiece at the start and the end positions of the carriage slide, respectively. The feasibility and reliability of the proposed motion error measurement system are demonstrated by the experimental results and the measurement uncertainty analysis.

Rolling Maneuver Load Alleviation using active controls

NASA Technical Reports Server (NTRS)

Woods-Vedeler, Jessica A.; Pototzky, Anthony S.

1992-01-01

Rolling Maneuver Load Alleviation (RMLA) has been demonstrated on the Active Flexible Wing (AFW) wind tunnel model in the NASA Langley Transonic Dynamics Tunnel. The design objective was to develop a systematic approach for developing active control laws to alleviate wing incremental loads during roll maneuvers. Using linear load models for the AFW wind-tunnel model which were based on experimental measurements, two RMLA control laws were developed based on a single-degree-of-freedom roll model. The RMLA control laws utilized actuation of outboard control surface pairs to counteract incremental loads generated during rolling maneuvers and actuation of the trailing edge inboard control surface pairs to maintain roll performance. To evaluate the RMLA control laws, roll maneuvers were performed in the wind tunnel at dynamic pressures of 150, 200, and 250 psf and Mach numbers of 0.33, .38 and .44, respectively. Loads obtained during these maneuvers were compared to baseline maneuver loads. For both RMLA controllers, the incremental torsion moments were reduced by up to 60 percent at all dynamic pressures and performance times. Results for bending moment load reductions during roll maneuvers varied. In addition, in a multiple function test, RMLA and flutter suppression system control laws were operated simultaneously during roll maneuvers at dynamic pressures 11 percent above the open-loop flutter dynamic pressure.

Left ventricle segmentation via two-layer level sets with circular shape constraint.

PubMed

Yang, Cong; Wu, Weiguo; Su, Yuanqi; Zhang, Shaoxiang

2017-05-01

This paper proposes a circular shape constraint and a novel two-layer level set method for the segmentation of the left ventricle (LV) from short-axis magnetic resonance images without training any shape models. Since the shape of LV throughout the apex-base axis is close to a ring shape, we propose a circle fitting term in the level set framework to detect the endocardium. The circle fitting term imposes a penalty on the evolving contour from its fitting circle, and thereby handles quite well with issues in LV segmentation, especially the presence of outflow track in basal slices and the intensity overlap between TPM and the myocardium. To extract the whole myocardium, the circle fitting term is incorporated into two-layer level set method. The endocardium and epicardium are respectively represented by two specified level contours of the level set function, which are evolved by an edge-based and a region-based active contour model. The proposed method has been quantitatively validated on the public data set from MICCAI 2009 challenge on the LV segmentation. Experimental results and comparisons with state-of-the-art demonstrate the accuracy and robustness of our method. Copyright © 2017 Elsevier Inc. All rights reserved.

Problem Posing and Problem Solving in a Math Teacher's Circle

ERIC Educational Resources Information Center

Appleton, Eric; Farina, Solange; Holzer, Tyler; Kotelawala, Usha; Trushkowsky, Mark

2017-01-01

This article describes the New York City Community of Adult Math Instructors (CAMI), a math teachers' circle founded in November 2014. The authors share details about their own participation in CAMI to show the professional growth that research-based, peer-led professional development can offer for adult educators.

The Present Perfect in World Englishes

ERIC Educational Resources Information Center

Yao, Xinyue; Collins, Peter

2012-01-01

This paper reports on a comprehensive corpus-based study of regional and stylistic variation in the distribution of the English present perfect. The data represents ten English varieties of both the Inner Circle and Outer Circle, covering four major text types: conversation, news reportage, academic and fictional writing. The results are discussed…

77 FR 8810 - Availability of Seats for the Gray's Reef National Marine Sanctuary Advisory Council

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-15

... Sanctuary Advisory Council: Sport diving and charter/commercial fishing. Applicants are chosen based upon..., Council Coordinator ( [email protected] , 10 Ocean Science Circle, Savannah, GA 31411; 912-598-2381..., Council Coordinator ( [email protected] , 10 Ocean Science Circle, Savannah, GA 31411; 912-598-2381...

77 FR 27719 - Availability of Seats for the Gray's Reef National Marine Sanctuary Advisory Council

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-11

...: sport fishing, conservation and charter/commercial fishing. Applicants are chosen based upon their..., Council Coordinator ( [email protected] , 10 Ocean Science Circle, Savannah, GA 31411; 912-598-2381..., Council Coordinator ( [email protected] , 10 Ocean Science Circle, Savannah, GA 31411; 912-598-2381...

A Sensor Fusion Method Based on an Integrated Neural Network and Kalman Filter for Vehicle Roll Angle Estimation.

PubMed

Vargas-Meléndez, Leandro; Boada, Beatriz L; Boada, María Jesús L; Gauchía, Antonio; Díaz, Vicente

2016-08-31

This article presents a novel estimator based on sensor fusion, which combines the Neural Network (NN) with a Kalman filter in order to estimate the vehicle roll angle. The NN estimates a "pseudo-roll angle" through variables that are easily measured from Inertial Measurement Unit (IMU) sensors. An IMU is a device that is commonly used for vehicle motion detection, and its cost has decreased during recent years. The pseudo-roll angle is introduced in the Kalman filter in order to filter noise and minimize the variance of the norm and maximum errors' estimation. The NN has been trained for J-turn maneuvers, double lane change maneuvers and lane change maneuvers at different speeds and road friction coefficients. The proposed method takes into account the vehicle non-linearities, thus yielding good roll angle estimation. Finally, the proposed estimator has been compared with one that uses the suspension deflections to obtain the pseudo-roll angle. Experimental results show the effectiveness of the proposed NN and Kalman filter-based estimator.

Double-dictionary matching pursuit for fault extent evaluation of rolling bearing based on the Lempel-Ziv complexity

NASA Astrophysics Data System (ADS)

Cui, Lingli; Gong, Xiangyang; Zhang, Jianyu; Wang, Huaqing

2016-12-01

The quantitative diagnosis of rolling bearing fault severity is particularly crucial to realize a proper maintenance decision. Aiming at the fault feature of rolling bearing, a novel double-dictionary matching pursuit (DDMP) for fault extent evaluation of rolling bearing based on the Lempel-Ziv complexity (LZC) index is proposed in this paper. In order to match the features of rolling bearing fault, the impulse time-frequency dictionary and modulation dictionary are constructed to form the double-dictionary by using the method of parameterized function model. Then a novel matching pursuit method is proposed based on the new double-dictionary. For rolling bearing vibration signals with different fault sizes, the signals are decomposed and reconstructed by the DDMP. After the noise reduced and signals reconstructed, the LZC index is introduced to realize the fault extent evaluation. The applications of this method to the fault experimental signals of bearing outer race and inner race with different degree of injury have shown that the proposed method can effectively realize the fault extent evaluation.

Generalized composite multiscale permutation entropy and Laplacian score based rolling bearing fault diagnosis

NASA Astrophysics Data System (ADS)

Zheng, Jinde; Pan, Haiyang; Yang, Shubao; Cheng, Junsheng

2018-01-01

Multiscale permutation entropy (MPE) is a recently proposed nonlinear dynamic method for measuring the randomness and detecting the nonlinear dynamic change of time series and can be used effectively to extract the nonlinear dynamic fault feature from vibration signals of rolling bearing. To solve the drawback of coarse graining process in MPE, an improved MPE method called generalized composite multiscale permutation entropy (GCMPE) was proposed in this paper. Also the influence of parameters on GCMPE and its comparison with the MPE are studied by analyzing simulation data. GCMPE was applied to the fault feature extraction from vibration signal of rolling bearing and then based on the GCMPE, Laplacian score for feature selection and the Particle swarm optimization based support vector machine, a new fault diagnosis method for rolling bearing was put forward in this paper. Finally, the proposed method was applied to analyze the experimental data of rolling bearing. The analysis results show that the proposed method can effectively realize the fault diagnosis of rolling bearing and has a higher fault recognition rate than the existing methods.

A Sensor Fusion Method Based on an Integrated Neural Network and Kalman Filter for Vehicle Roll Angle Estimation

PubMed Central

Vargas-Meléndez, Leandro; Boada, Beatriz L.; Boada, María Jesús L.; Gauchía, Antonio; Díaz, Vicente

2016-01-01

This article presents a novel estimator based on sensor fusion, which combines the Neural Network (NN) with a Kalman filter in order to estimate the vehicle roll angle. The NN estimates a “pseudo-roll angle” through variables that are easily measured from Inertial Measurement Unit (IMU) sensors. An IMU is a device that is commonly used for vehicle motion detection, and its cost has decreased during recent years. The pseudo-roll angle is introduced in the Kalman filter in order to filter noise and minimize the variance of the norm and maximum errors’ estimation. The NN has been trained for J-turn maneuvers, double lane change maneuvers and lane change maneuvers at different speeds and road friction coefficients. The proposed method takes into account the vehicle non-linearities, thus yielding good roll angle estimation. Finally, the proposed estimator has been compared with one that uses the suspension deflections to obtain the pseudo-roll angle. Experimental results show the effectiveness of the proposed NN and Kalman filter-based estimator. PMID:27589763

Fusion information entropy method of rolling bearing fault diagnosis based on n-dimensional characteristic parameter distance

NASA Astrophysics Data System (ADS)

Ai, Yan-Ting; Guan, Jiao-Yue; Fei, Cheng-Wei; Tian, Jing; Zhang, Feng-Ling

2017-05-01

To monitor rolling bearing operating status with casings in real time efficiently and accurately, a fusion method based on n-dimensional characteristic parameters distance (n-DCPD) was proposed for rolling bearing fault diagnosis with two types of signals including vibration signal and acoustic emission signals. The n-DCPD was investigated based on four information entropies (singular spectrum entropy in time domain, power spectrum entropy in frequency domain, wavelet space characteristic spectrum entropy and wavelet energy spectrum entropy in time-frequency domain) and the basic thought of fusion information entropy fault diagnosis method with n-DCPD was given. Through rotor simulation test rig, the vibration and acoustic emission signals of six rolling bearing faults (ball fault, inner race fault, outer race fault, inner-ball faults, inner-outer faults and normal) are collected under different operation conditions with the emphasis on the rotation speed from 800 rpm to 2000 rpm. In the light of the proposed fusion information entropy method with n-DCPD, the diagnosis of rolling bearing faults was completed. The fault diagnosis results show that the fusion entropy method holds high precision in the recognition of rolling bearing faults. The efforts of this study provide a novel and useful methodology for the fault diagnosis of an aeroengine rolling bearing.

Rolling-Bearing Service Life Based on Probable Cause for Removal: A Tutorial

NASA Technical Reports Server (NTRS)

Zaretsky, Erwin V.; Branzai, Emanuel V.

2017-01-01

In 1947 and 1952, Gustaf Lundberg and Arvid Palmgren developed what is now referred to as the Lundberg-Palmgren Model for Rolling Bearing Life Prediction based on classical rolling-element fatigue. Today, bearing fatigue probably accounts for less than 5 percent of bearings removed from service for cause. A bearing service life prediction methodology and tutorial indexed to eight probable causes for bearing removal, including fatigue, are presented, which incorporate strict series reliability; Weibull statistical analysis; available published field data from the Naval Air Rework Facility; and 224,000 rolling-element bearings removed for rework from commercial aircraft engines.

Determination of rolling resistance coefficient based on normal tyre stiffness

NASA Astrophysics Data System (ADS)

Rykov, S. P.; Tarasuyk, V. N.; Koval, V. S.; Ovchinnikova, N. I.; Fedotov, A. I.; Fedotov, K. V.

2018-03-01

The purpose of the article is to develop analytical dependence of wheel rolling resistance coefficient based on the mathematical description of normal tyre stiffness. The article uses the methods of non-holonomic mechanics and plane section methods. The article shows that the abscissa of gravity center of tyre stiffness expansion by the length of the contact area is the shift of normal road response. It can be used for determining rolling resistance coefficient. When determining rolling resistance coefficient using ellipsis and power function equations, one can reduce labor costs for testing and increase assessment accuracy.

Small-Molecule Organic Photovoltaic Modules Fabricated via Halogen-Free Solvent System with Roll-to-Roll Compatible Scalable Printing Method.

PubMed

Heo, Youn-Jung; Jung, Yen-Sook; Hwang, Kyeongil; Kim, Jueng-Eun; Yeo, Jun-Seok; Lee, Sehyun; Jeon, Ye-Jin; Lee, Donmin; Kim, Dong-Yu

2017-11-15

For the first time, the photovoltaic modules composed of small molecule were successfully fabricated by using roll-to-roll compatible printing techniques. In this study, blend films of small molecules, BTR and PC 71 BM were slot-die coated using a halogen-free solvent system. As a result, high efficiencies of 7.46% and 6.56% were achieved from time-consuming solvent vapor annealing (SVA) treatment and roll-to-roll compatible solvent additive approaches, respectively. After successful verification of our roll-to-roll compatible method on small-area devices, we further fabricated large-area photovoltaic modules with a total active area of 10 cm 2 , achieving a power conversion efficiency (PCE) of 4.83%. This demonstration of large-area photovoltaic modules through roll-to-roll compatible printing methods, even based on a halogen-free solvent, suggests the great potential for the industrial-scale production of organic solar cells (OSCs).

Experimental analysis of two-layered dissimilar metals by roll bonding

NASA Astrophysics Data System (ADS)

Zhao, Guanghui; Li, Yugui; Li, Juan; Huang, Qingxue; Ma, Lifeng

2018-02-01

Rolling reduction and base layers thickness have important implications for rolling compounding. A two-layered 304 stainless steel/Q345R low alloyed steel was roll bonded. The roll bonding was performed at the three thickness reductions of 25%, 40% and 55% with base layers of various thicknesses (Q345R). The microstructures of the composite were investigated by the ultra-deep microscope (OM) and scanning electron microscope (SEM) and Transmission electron microscope (TEM). Simultaneously, the mechanical properties of the composite were experimentally measured and the tensile fracture surfaces were observed by SEM. The interfaces were successfully bonded without any cracking or voids, which indicated a good fabrication of the 304/Q345R composite. The rolling reduction rate and thinning increase of the substrate contributed to the bonding effects appearance of the roll bonded sheet. The Cr and Ni enriched diffusion layer was formed by the interface elements diffusion. The Cr and Ni diffusion led to the formation of ˜10 μm wide Cr and Ni layers on the carbon steel side.

High volume nanoscale roll-based imprinting using jet and flash imprint lithography

NASA Astrophysics Data System (ADS)

Ahn, Se Hyun; Miller, Michael; Yang, Shuqiang; Ganapathisubramanian, Maha; Menezes, Marlon; Singh, Vik; Wan, Fen; Choi, Jin; Xu, Frank; LaBrake, Dwayne; Resnick, Douglas J.; Hofemann, Paul; Sreenivasan, S. V.

2014-03-01

Extremely large-area roll-to-roll manufacturing on flexible substrates is ubiquitous for applications such as paper and plastic processing. The challenge is to extend this approach to the realm of nanopatterning and realize similar benefits. Display applications, including liquid crystal (LCD), organic light emitting diode (OLED) and flexible displays are particularly interesting because of the ability to impact multiple levels in the basic display. Of particular interest are the polarizer, DBEF, thin film transistor and color filter; roll-based imprinting has the opportunity to create high performance components within the display while improving the cost of ownership of the panel. Realization of these devices requires both a scalable imprinting technology and tool. In this paper, we introduce a high volume roll-based nanopatterning system, the LithoFlex 350TM. The LithoFlex 350 uses an inkjet based imprinting process similar to the technology demonstrator tool, the LithoFlex 100, introduced in 2012. The width of the web is 350mm and patterning width is 300mm. The system can be configured either for Plate-to-Roll (P2R) imprinting (in which a rigid template is used to pattern the flexible web material) or for Roll-to-Plate imprinting (R2P) (in which a web based template is used to pattern either wafers or panels). Also described in this paper are improvements to wire grid polarizer devices. By optimizing the deposition, patterning and etch processes, we have been able to create working WGPs with transmittance and extinction ratios as high as 44% and 50,000, respectively.

Roll-to-Roll production of carbon nanotubes based supercapacitors

NASA Astrophysics Data System (ADS)

Zhu, Jingyi; Childress, Anthony; Karakaya, Mehmet; Roberts, Mark; Arcilla-Velez, Margarita; Podila, Ramakrishna; Rao, Apparao

2014-03-01

Carbon nanomaterials provide an excellent platform for electrochemical double layer capacitors (EDLCs). However, current industrial methods for producing carbon nanotubes are expensive and thereby increase the costs of energy storage to more than 10 Wh/kg. In this regard, we developed a facile roll-to-roll production technology for scalable manufacturing of multi-walled carbon nanotubes (MWNTs) with variable density on run-of-the-mill kitchen Al foils. Our method produces MWNTs with diameter (heights) between 50-100 nm (10-100 μm), and a specific capacitance as high as ~ 100 F/g in non-aqueous electrolytes. In this talk, the fundamental challenges involved in EDLC-suitable MWNT growth, roll-to-roll production, and device manufacturing will be discussed along with electrochemical characteristics of roll-to-roll MWNTs. Research supported by NSF CMMI Grant1246800.

Differentiating through Literature Circles

ERIC Educational Resources Information Center

Helgeson, John

2017-01-01

This article begins with an example of a typical middle-school experience with literature circles. Students read a common text and come prepared to share and discuss the text based on individual roles they are assigned. Teachers are using this practice to address the complexity levels of texts in order to help students develop the skills they need…

Principles and Practices of the Circle of Trust[R] Approach

ERIC Educational Resources Information Center

Chadsey, Terry; Jackson, Marcy

2012-01-01

Through the Center for Courage & Renewal, the authors offer personal and professional retreats and programs designed to explore vocational and life questions, offer renewal and encouragement, and deepen engagement in professional practice. Using what they call the Circle of Trust[R] approach, they invite groups into a communal process based upon a…

Relations among Five Radii of Circles in a Triangle, Its Sides and Other Segments

ERIC Educational Resources Information Center

Sigler, Avi; Stupel, Moshe; Flores, Alfinio

2017-01-01

Students use GeoGebra to explore the mathematical relations among different radii of circles in a triangle (circumcircle, incircle, excircles) and the sides and other segments in the triangle. The more formal mathematical development of the relations that follows the explorations is based on known geometrical properties, different formulas…

A star recognition method based on the Adaptive Ant Colony algorithm for star sensors.

PubMed

Quan, Wei; Fang, Jiancheng

2010-01-01

A new star recognition method based on the Adaptive Ant Colony (AAC) algorithm has been developed to increase the star recognition speed and success rate for star sensors. This method draws circles, with the center of each one being a bright star point and the radius being a special angular distance, and uses the parallel processing ability of the AAC algorithm to calculate the angular distance of any pair of star points in the circle. The angular distance of two star points in the circle is solved as the path of the AAC algorithm, and the path optimization feature of the AAC is employed to search for the optimal (shortest) path in the circle. This optimal path is used to recognize the stellar map and enhance the recognition success rate and speed. The experimental results show that when the position error is about 50″, the identification success rate of this method is 98% while the Delaunay identification method is only 94%. The identification time of this method is up to 50 ms.

A hybrid feature selection and health indicator construction scheme for delay-time-based degradation modelling of rolling element bearings

NASA Astrophysics Data System (ADS)

Zhang, Bin; Deng, Congying; Zhang, Yi

2018-03-01

Rolling element bearings are mechanical components used frequently in most rotating machinery and they are also vulnerable links representing the main source of failures in such systems. Thus, health condition monitoring and fault diagnosis of rolling element bearings have long been studied to improve operational reliability and maintenance efficiency of rotatory machines. Over the past decade, prognosis that enables forewarning of failure and estimation of residual life attracted increasing attention. To accurately and efficiently predict failure of the rolling element bearing, the degradation requires to be well represented and modelled. For this purpose, degradation of the rolling element bearing is analysed with the delay-time-based model in this paper. Also, a hybrid feature selection and health indicator construction scheme is proposed for extraction of the bearing health relevant information from condition monitoring sensor data. Effectiveness of the presented approach is validated through case studies on rolling element bearing run-to-failure experiments.

Promoting retention, enabling success: Discovering the potential of student support circles.

PubMed

Bass, Janice; Walters, Caroline; Toohill, Jocelyn; Sidebotham, Mary

2016-09-01

Retention of students is critical to education programs and future workforce. A mixed methods study evaluated student engagement within a Bachelor of Midwifery program and connection with career choice through participation in student support circles. Centred on the Five Senses of Success Framework (sense of capability, purpose, identity, resourcefulness and connectedness) and including four stages of engagement (creating space, preparing self, sharing stories, focused conversations), the circles support and develop student and professional identity. Of 80 students 43 (54%) provided responses to a two item survey assessed against a five point Likert scale to determine utility. Using a nominal group technique, student's voices gave rich insight into the personal and professional growth that participation in the student support circles provided. Evaluated as helpful to first year students in orientating to university study and early socialisation into the profession, the circles appear to influence the development of a strong sense of professional identity and personal midwifery philosophy based on the relational nature of the midwife being with woman rather than doing midwifery. This suggests that student support circles positively influence perceptions and expectations, contributing to a shared sense of purpose and discipline connection, for enhancing student retention and future workforce participation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Flow Regime Based Climatologies of Lightning Probabilities for Spaceports and Airports

NASA Technical Reports Server (NTRS)

Bauman, William H., III; Volmer, Matthew; Sharp, David; Spratt, Scott; Lafosse, Richard A.

2007-01-01

Objective: provide forecasters with a "first guess" climatological lightning probability tool (1) Focus on Space Shuttle landings and NWS T AFs (2) Four circles around sites: 5-, 10-, 20- and 30 n mi (4) Three time intervals: hourly, every 3 hr and every 6 hr It is based on: (1) NLDN gridded data (2) Flow regime (3) Warm season months of May-Sep for years 1989-2004 Gridded data and available code yields squares, not circles Over 850 spread sheets converted into manageable user-friendly web-based GUI

Iron aluminide knife and method thereof

DOEpatents

Sikka, Vinod K.

1997-01-01

Fabricating an article of manufacture having a Fe.sub.3 Al-based alloy cutting edge. The fabrication comprises the steps of casting an Fe.sub.3 Al-based alloy, extruding into rectangular cross section, rolling into a sheet at 800.degree. C. for a period of time followed by rolling at 650.degree. C., cutting the rolled sheet into an article having an edge, and grinding the edge of the article to form a cutting edge.

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.

Design of Low-Cost Vehicle Roll Angle Estimator Based on Kalman Filters and an Iot Architecture.

PubMed

Garcia Guzman, Javier; Prieto Gonzalez, Lisardo; Pajares Redondo, Jonatan; Sanz Sanchez, Susana; Boada, Beatriz L

2018-06-03

In recent years, there have been many advances in vehicle technologies based on the efficient use of real-time data provided by embedded sensors. Some of these technologies can help you avoid or reduce the severity of a crash such as the Roll Stability Control (RSC) systems for commercial vehicles. In RSC, several critical variables to consider such as sideslip or roll angle can only be directly measured using expensive equipment. These kind of devices would increase the price of commercial vehicles. Nevertheless, sideslip or roll angle or values can be estimated using MEMS sensors in combination with data fusion algorithms. The objectives stated for this research work consist of integrating roll angle estimators based on Linear and Unscented Kalman filters to evaluate the precision of the results obtained and determining the fulfillment of the hard real-time processing constraints to embed this kind of estimators in IoT architectures based on low-cost equipment able to be deployed in commercial vehicles. An experimental testbed composed of a van with two sets of low-cost kits was set up, the first one including a Raspberry Pi 3 Model B, and the other having an Intel Edison System on Chip. This experimental environment was tested under different conditions for comparison. The results obtained from low-cost experimental kits, based on IoT architectures and including estimators based on Kalman filters, provide accurate roll angle estimation. Also, these results show that the processing time to get the data and execute the estimations based on Kalman Filters fulfill hard real time constraints.

Experiment Research on Hot-Rolling Processing of Nonsmooth Pit Surface.

PubMed

Gu, Yun-Qing; Fan, Tian-Xing; Mou, Jie-Gang; Yu, Wei-Bo; Zhao, Gang; Wang, Evan

2016-01-01

In order to achieve the nonsmooth surface drag reduction structure on the inner polymer coating of oil and gas pipelines and improve the efficiency of pipeline transport, a structural model of the machining robot on the pipe inner coating is established. Based on machining robot, an experimental technique is applied to research embossing and coating problems of rolling-head, and then the molding process rules under different conditions of rolling temperatures speeds and depth are analyzed. Also, an orthogonal experiment analysis method is employed to analyze the different effects of hot-rolling process apparatus on the embossed pits morphology and quality of rolling. The results also reveal that elevating the rolling temperature or decreasing the rolling speed can also improve the pit structure replication rates of the polymer coating surface, and the rolling feed has little effect on replication rates. After the rolling-head separates from the polymer coating, phenomenon of rebounding and refluxing of the polymer coating occurs, which is the reason of inability of the process. A continuous hot-rolling method for processing is used in the robot and the hot-rolling process of the processing apparatus is put in a dynamics analysis.

Experiment Research on Hot-Rolling Processing of Nonsmooth Pit Surface

PubMed Central

Gu, Yun-qing; Fan, Tian-xing; Mou, Jie-gang; Yu, Wei-bo; Zhao, Gang; Wang, Evan

2016-01-01

In order to achieve the nonsmooth surface drag reduction structure on the inner polymer coating of oil and gas pipelines and improve the efficiency of pipeline transport, a structural model of the machining robot on the pipe inner coating is established. Based on machining robot, an experimental technique is applied to research embossing and coating problems of rolling-head, and then the molding process rules under different conditions of rolling temperatures speeds and depth are analyzed. Also, an orthogonal experiment analysis method is employed to analyze the different effects of hot-rolling process apparatus on the embossed pits morphology and quality of rolling. The results also reveal that elevating the rolling temperature or decreasing the rolling speed can also improve the pit structure replication rates of the polymer coating surface, and the rolling feed has little effect on replication rates. After the rolling-head separates from the polymer coating, phenomenon of rebounding and refluxing of the polymer coating occurs, which is the reason of inability of the process. A continuous hot-rolling method for processing is used in the robot and the hot-rolling process of the processing apparatus is put in a dynamics analysis. PMID:27022235

Ultrashort-pulsed laser processing and solution based coating in roll-to-roll manufacturing of organic photovoltaics

NASA Astrophysics Data System (ADS)

Hördemann, C.; Hirschfelder, K.; Schaefer, M.; Gillner, A.

2015-09-01

The breakthrough of flexible organic electronics and especially organic photovoltaics is highly dependent on cost-efficient production technologies. Roll-2-Roll processes show potential for a promising solution in terms of high throughput and low-cost production of thin film organic components. Solution based material deposition and integrated laser patterning processes offer new possibilities for versatile production lines. The use of flexible polymeric substrates brings along challenges in laser patterning which have to be overcome. One main challenge when patterning transparent conductive layers on polymeric substrates are material bulges at the edges of the ablated area. Bulges can lead to short circuits in the layer system leading to device failure. Therefore following layers have to have a sufficient thickness to cover and smooth the ridge. In order to minimize the bulging height, a study has been carried out on transparent conductive ITO layers on flexible PET substrates. Ablation results using different beam shapes, such as Gaussian beam, Top-Hat beam and Donut-shaped beam, as well as multi-pass scribing and double-pulsed ablation are compared. Furthermore, lab scale methods for cleaning the patterned layer and eliminating bulges are contrasted to the use of additional water based sacrificial layers in order to obtain an alternative procedure suitable for large scale Roll-2-Roll manufacturing. Besides progress in research, ongoing transfer of laser processes into a Roll-2-Roll demonstrator is illustrated. By using fixed optical elements in combination with a galvanometric scanner, scribing, variable patterning and edge deletion can be performed individually.

Using Reading Circles Strategy for Developing Preparatory Students' Critical Reading Skills and Social Skills

ERIC Educational Resources Information Center

Abdelrasoul, Mohamed Mahmoud Ibrahim

2014-01-01

The present study aimed at developing the necessary critical reading skills and social skills of the Egyptian EFL second year preparatory school students, through a proposed program based on using reading circles strategy. The study participants were 44 students from Sohag Experimental Preparatory School in Sohag Governorate. Instruments of the…

Raccoon Circles: A Handbook for Facilitators.

ERIC Educational Resources Information Center

Cain, Jim

This handbook presents a collection of over 35 experiential and adventure-based activities using only a single item of equipment--a 15-foot long section of 1-inch tubular climbing webbing, called a raccoon circle. Some of the activities are quiet, some are loud, and they range from low to high challenge levels. Different-sized groups can be…

A Cost-Benefit Analysis of Hollow Water's Community Holistic Circle Healing Process.

ERIC Educational Resources Information Center

Couture, Joe; Parker, Ted; Couture, Ruth; Laboucane, Patti

Four Native American communities in Manitoba (Canada) known as Hollow Water devised a healing system for sexual abuse--the Hollow Water First Nation Community Holistic Circle Healing (CHCH). While integrating elements of a number of federal and provincially funded services, the 13-step CHCH healing process is based on the seven Midewin teachings…

Hierarchical den selection of Canada lynx in western Montana

Treesearch

John R. Squires; Nicholas J. Decesare; Jay A. Kolbe; Leonard F. Ruggiero

2008-01-01

We studied den selection of Canada lynx (Lynx canadensis; hereafter lynx) at multiple ecological scales based on 57 dens from 19 females located in western Montana, USA, between 1999 and 2006. We considered 3 spatial scales in this analysis, including den site (11-m-radius circle surrounding dens), den area (100-m-radius circle), and den environ (1-...

Constructing Knowledge about the Trigonometric Functions and Their Geometric Meaning on the Unit Circle

ERIC Educational Resources Information Center

Altman, Renana; Kidron, Ivy

2016-01-01

Processes of knowledge construction are investigated. A learner is constructing knowledge about the trigonometric functions and their geometric meaning on the unit circle. The analysis is based on the dynamically nested epistemic action model for abstraction in context. Different tasks are offered to the learner. In his effort to perform the…

Toward large-area roll-to-roll printed nanophotonic sensors

NASA Astrophysics Data System (ADS)

Karioja, Pentti; Hiltunen, Jussi; Aikio, Sanna M.; Alajoki, Teemu; Tuominen, Jarkko; Hiltunen, Marianne; Siitonen, Samuli; Kontturi, Ville; Böhlen, Karl; Hauser, Rene; Charlton, Martin; Boersma, Arjen; Lieberzeit, Peter; Felder, Thorsten; Eustace, David; Haskal, Eliav

2014-05-01

Polymers have become an important material group in fabricating discrete photonic components and integrated optical devices. This is due to their good properties: high optical transmittance, versatile processability at relative low temperatures and potential for low-cost production. Recently, nanoimprinting or nanoimprint lithography (NIL) has obtained a plenty of research interest. In NIL, a mould is pressed against a substrate coated with a moldable material. After deformation of the material, the mold is separated and a replica of the mold is formed. Compared with conventional lithographic methods, imprinting is simple to carry out, requires less-complicated equipment and can provide high-resolution with high throughput. Nanoimprint lithography has shown potential to become a method for low-cost and high-throughput fabrication of nanostructures. We show the development process of nano-structured, large-area multi-parameter sensors using Photonic Crystal (PC) and Surface Enhanced Raman Scattering (SERS) methodologies for environmental and pharmaceutical applications. We address these challenges by developing roll-to-roll (R2R) UV-nanoimprint fabrication methods. Our development steps are the following: Firstly, the proof of concept structures are fabricated by the use of wafer-level processes in Si-based materials. Secondly, the master molds of successful designs are fabricated, and they are used to transfer the nanophotonic structures into polymer materials using sheet-level UV-nanoimprinting. Thirdly, the sheet-level nanoimprinting processes are transferred to roll-to-roll fabrication. In order to enhance roll-to-roll manufacturing capabilities, silicone-based polymer material development was carried out. In the different development phases, Photonic Crystal and SERS sensor structures with increasing complexities were fabricated using polymer materials in order to enhance sheet-level and roll-to-roll manufacturing processes. In addition, chemical and molecular imprint (MIP) functionalization methods were applied in the sensor demonstrators. In this paper, the process flow in fabricating large-area nanophotonic structures by the use of sheet-level and roll-to-roll UV- nanoimprinting is reported.

Iron aluminide knife and method thereof

DOEpatents

Sikka, V.K.

1997-08-05

Fabricating an article of manufacture having a Fe{sub 3}Al-based alloy cutting edge is discussed. The fabrication comprises the steps of casting an Fe{sub 3}Al-based alloy, extruding into rectangular cross section, rolling into a sheet at 800 C for a period of time followed by rolling at 650 C, cutting the rolled sheet into an article having an edge, and grinding the edge of the article to form a cutting edge. 1 fig.

Scalability of carbon-nanotube-based thin film transistors for flexible electronic devices manufactured using an all roll-to-roll gravure printing system

PubMed Central

Koo, Hyunmo; Lee, Wookyu; Choi, Younchang; Sun, Junfeng; Bak, Jina; Noh, Jinsoo; Subramanian, Vivek; Azuma, Yasuo; Majima, Yutaka; Cho, Gyoujin

2015-01-01

To demonstrate that roll-to-roll (R2R) gravure printing is a suitable advanced manufacturing method for flexible thin film transistor (TFT)-based electronic circuits, three different nanomaterial-based inks (silver nanoparticles, BaTiO3 nanoparticles and single-walled carbon nanotubes (SWNTs)) were selected and optimized to enable the realization of fully printed SWNT-based TFTs (SWNT-TFTs) on 150-m-long rolls of 0.25-m-wide poly(ethylene terephthalate) (PET). SWNT-TFTs with 5 different channel lengths, namely, 30, 80, 130, 180, and 230 μm, were fabricated using a printing speed of 8 m/min. These SWNT-TFTs were characterized, and the obtained electrical parameters were related to major mechanical factors such as web tension, registration accuracy, impression roll pressure and printing speed to determine whether these mechanical factors were the sources of the observed device-to-device variations. By utilizing the electrical parameters from the SWNT-TFTs, a Monte Carlo simulation for a 1-bit adder circuit, as a reference, was conducted to demonstrate that functional circuits with reasonable complexity can indeed be manufactured using R2R gravure printing. The simulation results suggest that circuits with complexity, similar to the full adder circuit, can be printed with a 76% circuit yield if threshold voltage (Vth) variations of less than 30% can be maintained. PMID:26411839

Stereotypic circling behavior in mice with vestibular dysfunction: asymmetrical effects of intrastriatal microinjection of a dopamine agonist.

PubMed

Ishiguro, Akio; Inagaki, Masumi; Kaga, Makiko

2007-07-01

Bronx Waltzer (bv) mouse, which has been used as a model of hearing and vestibular dysfunction, shows remarkable repetitive circling behavior. This study investigated whether the behavior is caused by the asymmetry of striatal function by observing the behavior of the bv mice following microinjection of dopamine D1 agonist, A68930 into the striatum ipsilaterally and contralaterally to the preferred direction of rotation separately. High dose of the drug induced opposite effects on ipsilateral rotations by the side of injections with statistical significance (p = .0026). These results suggested that the stereotypic circling behavior involves striatum and is based on striatal asymmetry.

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.

9. DETAIL VIEW OF ROLLING EXPANSION JOINT, NORTHEAST BASE OF ...

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

9. DETAIL VIEW OF ROLLING EXPANSION JOINT, NORTHEAST BASE OF SECOND CLOSED SPANDREL ARCH AT JUNCTION OF OPEN SPANDREL ARCH, LOOKING EAST - Virgin River Bridge, Spanning Virgin River on State Highway 9, Hurricane, Washington County, UT

Rolling into spatial disorientation: simulator demonstration of the post-roll (Gillingham) illusion.

PubMed

Nooij, Suzanne A E; Groen, Eric L

2011-05-01

Spatial disorientation (SD) is still a contributing factor in many aviation accidents, stressing the need for adequate SD training scenarios. In this article we focused on the post-roll effect (the sensation of rolling back after a roll maneuver, such as an entry of a coordinated turn) and investigated the effect of roll stimuli on the pilot's ability to stabilize their roll attitude. This resulted in a ground-based demonstration scenario for pilots. The experiments took place in the advanced 6-DOF Desdemona motion simulator, with the subject in a supine position. Roll motions were either fully automated with the subjects blindfolded (BLIND), automated with the subject viewing the cockpit interior (COCKPIT), or self-controlled (LEAD). After the roll stimulus subjects had to cancel all perceived simulator motion without any visual feedback. Both the roll velocity and duration were varied. In 68% of all trials subjects corrected for the perceived motion of rolling back by initiating a roll motion in the same direction as the preceeding roll. The effect was dependent on both rate and duration, in a manner consistent with semicircular canal dynamics. The effect was smallest in the BLIND scenario, but differences between simulation scenarios were non-significant. The results show that the effects of the post-roll illusion on aircraft control can be demonstrated adequately in a flight simulator using an attitude control task. The effect is present even after short roll movements, occurring frequently in flight. Therefore this demonstration is relevant for spatial disorientation training programs for pilots.

Manufacturing Demonstration Facility: Roll-to-Roll Processing

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

Datskos, Panos G; Joshi, Pooran C; List III, Frederick Alyious

This Manufacturing Demonstration Facility (MDF)e roll-to-roll processing effort described in this report provided an excellent opportunity to investigate a number of advanced manufacturing approaches to achieve a path for low cost devices and sensors. Critical to this effort is the ability to deposit thin films at low temperatures using nanomaterials derived from nanofermentation. The overarching goal of this project was to develop roll-to-roll manufacturing processes of thin film deposition on low-cost flexible substrates for electronics and sensor applications. This project utilized ORNL s unique Pulse Thermal Processing (PTP) technologies coupled with non-vacuum low temperature deposition techniques, ORNL s clean roommore » facility, slot dye coating, drop casting, spin coating, screen printing and several other equipment including a Dimatix ink jet printer and a large-scale Kyocera ink jet printer. The roll-to-roll processing project had three main tasks: 1) develop and demonstrate zinc-Zn based opto-electronic sensors using low cost nanoparticulate structures manufactured in a related MDF Project using nanofermentation techniques, 2) evaluate the use of silver based conductive inks developed by project partner NovaCentrix for electronic device fabrication, and 3) demonstrate a suite of low cost printed sensors developed using non-vacuum deposition techniques which involved the integration of metal and semiconductor layers to establish a diverse sensor platform technology.« less

Construction of edge cracks pre-criterion model based on hot rolling experiment and simulation of AZ31 magnesium alloy

NASA Astrophysics Data System (ADS)

Ning, Fangkun; Jia, Weitao; Hou, Jian; Chen, Xingrui; Le, Qichi

2018-05-01

Various fracture criteria, especially Johnson and Cook (J-C) model and (normalized) Cockcroft and Latham (C-L) criterion were contrasted and discussed. Based on normalized C-L criterion, adopted in this paper, FE simulation was carried out and hot rolling experiments under temperature range of 200 °C–350 °C, rolling reduction rate of 25%–40% and rolling speed from 7–21 r/min was implemented. The microstructure was observed by optical microscope and damage values of simulation results were contrasted with the length of cracks on diverse parameters. The results show that the plate generated less edge cracks and the microstructure emerged slight shear bands and fine dynamic recrystallization grains rolled at 350 °C, 40% reduction and 14 r/min. The edge cracks pre-criterion model was obtained combined with Zener-Hollomon equation and deformation activation energy.

High-rate, roll-to-roll nanomanufacturing of flexible systems

NASA Astrophysics Data System (ADS)

Cooper, Khershed P.; Wachter, Ralph F.

2012-10-01

Since the National Nanotechnology Initiative was first announced in 2000, nanotechnology has developed an impressive catalog of nano-scale structures with building-blocks such as nanoparticles, nanotubes, nanorods, nanopillars, and quantum dots. Similarly, there are accompanying materials processes such as, atomic layer deposition, pulsed layer deposition, nanoprinting, nanoimprinting, transfer printing, nanolithography and nanopatterning. One of the challenges of nanomanufacturing is scaling up these processes reliably and affordably. Roll-to-roll manufacturing is a means for scaling up, for increasing throughput. It is high-speed production using a continuous, moving platform such as a web or a flexible substrate. The adoption of roll-to-roll to nanomanufacturing is novel. The goal is to build structures and devices with nano-scale features and specific functionality. The substrate could be a polymer, metal foil, silk, cloth or paper. The materials to build the structures and multi-level devices could be organic, inorganic or biological. Processing could be solution-based, e.g., ink-jet printing, or vacuum-based, e.g., chemical vapor deposition. Products could be electronics, optoelectronics, membranes, catalysts, microfluidics, lab-on-film, filters, etc. By this means, processing of large and conformal areas is achievable. High-throughput translates into low cost, which is the attraction of roll-to-roll nanomanufacturing. There are technical challenges requiring fundamental scientific advances in materials and process development and in manufacturing and system-integration where achieving nano-scale feature size, resolution and accuracy at high speeds can be major hurdles. We will give an overview of roll-to-roll nanomanufacturing with emphasis on the need to understand the material, process and system complexities, the need for instrumentation, measurement, and process control and describe the concept of cyber-enabled nanomanufacturing for reliable and predictable production.

Phase-field modeling of liquids splitting between separating surfaces and its application to high-resolution roll-based printing technologies

NASA Astrophysics Data System (ADS)

Hizir, F. E.; Hardt, D. E.

2017-05-01

An in-depth understanding of the liquid transport in roll-based printing systems is essential for advancing the roll-based printing technology and enhancing the performance of the printed products. In this study, phase-field simulations are performed to characterize the liquid transport in roll-based printing systems, and the phase-field method is shown to be an effective tool to simulate the liquid transport. In the phase-field simulations, the liquid transport through the ink transfer rollers is approximated as the stretching and splitting of liquid bridges with pinned or moving contact lines between vertically separating surfaces. First, the effect of the phase-field parameters and the mesh characteristics on the simulation results is examined. The simulation results show that a sharp interface limit is approached as the capillary width decreases while keeping the mobility proportional to the capillary width squared. Close to the sharp interface limit, the mobility changes over a specified range are observed to have no significant influence on the simulation results. Next, the ink transfer from the cells on the surface of an ink-metering roller to the surface of stamp features is simulated. Under negligible inertial effects and in the absence of gravity, the amount of liquid ink transferred from an axisymmetric cell with low surface wettability to a stamp with high surface wettability is found to increase as the cell sidewall steepness and the cell surface wettability decrease and the stamp surface wettability and the capillary number increase. Strategies for improving the resolution and quality of roll-based printing are derived based on an analysis of the simulation results. The application of novel materials that contain cells with irregular surface topography to stamp inking in high-resolution roll-based printing is assessed.

Nanostructured Mg 2Ni materials prepared by cold rolling and used as negative electrode for Ni-MH batteries

NASA Astrophysics Data System (ADS)

Pedneault, Sylvain; Huot, Jacques; Roué, Lionel

In the present work, cold rolling has been investigated as a new means of producing Mg-based metal hydrides for nickel-metal hydride (Ni-MH) batteries. Structure and electrochemical evolution of 2Mg-Ni cold-rolled samples were investigated as a function of the number of rolling passes as well as heat treatment. It was found that nanocrystalline Mg 2Ni alloy can be obtained by an appropriate three step process involving rolling, heat treatment and rolling again. It was shown that the number of primary and secondary rolling passes must be carefully optimized in order to favour the complete formation of Mg 2Ni alloy having a nanocrystalline structure (∼10 nm in crystallite size) without excessive sample oxidation. Actually, the best result was obtained by first rolling 90 times, followed by a heat treatment at 400 °C for 4 h and roll again 20 times. The resulting material displayed an initial discharge capacity of 205 mAh g -1, which is quite similar to that obtained with ball-milled Mg 2Ni alloy.

Microstructure based procedure for process parameter control in rolling of aluminum thin foils

NASA Astrophysics Data System (ADS)

Johannes, Kronsteiner; Kabliman, Evgeniya; Klimek, Philipp-Christoph

2018-05-01

In present work, a microstructure based procedure is used for a numerical prediction of strength properties for Al-Mg-Sc thin foils during a hot rolling process. For this purpose, the following techniques were developed and implemented. At first, a toolkit for a numerical analysis of experimental stress-strain curves obtained during a hot compression testing by a deformation dilatometer was developed. The implemented techniques allow for the correction of a temperature increase in samples due to adiabatic heating and for the determination of a yield strength needed for the separation of the elastic and plastic deformation regimes during numerical simulation of multi-pass hot rolling. At the next step, an asymmetric Hot Rolling Simulator (adjustable table inlet/outlet height as well as separate roll infeed) was developed in order to match the exact processing conditions of a semi-industrial rolling procedure. At each element of a finite element mesh the total strength is calculated by in-house Flow Stress Model based on evolution of mean dislocation density. The strength values obtained by numerical modelling were found in a reasonable agreement with results of tensile tests for thin Al-Mg-Sc foils. Thus, the proposed simulation procedure might allow to optimize the processing parameters with respect to the microstructure development.

Universal Stoppers Are Rupert

ERIC Educational Resources Information Center

Jerrard, Richard P.; Wetzel, John E.

2008-01-01

A stopper is called "universal" if it can be used to plug pipes whose cross-sections are a circle, a square, and an isosceles triangle, with the diameter of the circle, the side of the square, and the base and altitude of the triangle all equal. Echoing the well-known result for equal cubes that is attributed to Prince Rupert, we show that it is…

View of Staff Officers' Quarters Area from Staff Circle. Building ...

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

View of Staff Officers' Quarters Area from Staff Circle. Building No. 403 is to the right, Building No. 404 is to the left, and Building No. 405 is in far left in background. Facing west - MacDill Air Force Base, Bounded by City of Tampa North, Tampa Bay South, Old Tampa Bay West, & Hillsborough Bay East, Tampa, Hillsborough County, FL

Metagenomic characterization of airborne viral DNA diversity in the near-surface atmosphere.

PubMed

Whon, Tae Woong; Kim, Min-Soo; Roh, Seong Woon; Shin, Na-Ri; Lee, Hae-Won; Bae, Jin-Woo

2012-08-01

Airborne viruses are expected to be ubiquitous in the atmosphere but they still remain poorly understood. This study investigated the temporal and spatial dynamics of airborne viruses and their genotypic characteristics in air samples collected from three distinct land use types (a residential district [RD], a forest [FR], and an industrial complex [IC]) and from rainwater samples freshly precipitated at the RD site (RD-rain). Viral abundance exhibited a seasonal fluctuation in the range between 1.7 × 10(6) and 4.0 × 10(7) viruses m(-3), which increased from autumn to winter and decreased toward spring, but no significant spatial differences were observed. Temporal variations in viral abundance were inversely correlated with seasonal changes in temperature and absolute humidity. Metagenomic analysis of air viromes amplified by rolling-circle phi29 polymerase-based random hexamer priming indicated the dominance of plant-associated single-stranded DNA (ssDNA) geminivirus-related viruses, followed by animal-infecting circovirus-related sequences, with low numbers of nanoviruses and microphages-related genomes. Particularly, the majority of the geminivirus-related viruses were closely related to ssDNA mycoviruses that infect plant-pathogenic fungi. Phylogenetic analysis based on the replication initiator protein sequence indicated that the airborne ssDNA viruses were distantly related to known ssDNA viruses, suggesting that a high diversity of viruses were newly discovered. This research is the first to report the seasonality of airborne viruses and their genetic diversity, which enhances our understanding of viral ecology in temperate regions.

Metagenomic Characterization of Airborne Viral DNA Diversity in the Near-Surface Atmosphere

PubMed Central

Whon, Tae Woong; Kim, Min-Soo; Roh, Seong Woon; Shin, Na-Ri; Lee, Hae-Won

2012-01-01

Airborne viruses are expected to be ubiquitous in the atmosphere but they still remain poorly understood. This study investigated the temporal and spatial dynamics of airborne viruses and their genotypic characteristics in air samples collected from three distinct land use types (a residential district [RD], a forest [FR], and an industrial complex [IC]) and from rainwater samples freshly precipitated at the RD site (RD-rain). Viral abundance exhibited a seasonal fluctuation in the range between 1.7 × 106 and 4.0 × 107 viruses m−3, which increased from autumn to winter and decreased toward spring, but no significant spatial differences were observed. Temporal variations in viral abundance were inversely correlated with seasonal changes in temperature and absolute humidity. Metagenomic analysis of air viromes amplified by rolling-circle phi29 polymerase-based random hexamer priming indicated the dominance of plant-associated single-stranded DNA (ssDNA) geminivirus-related viruses, followed by animal-infecting circovirus-related sequences, with low numbers of nanoviruses and microphages-related genomes. Particularly, the majority of the geminivirus-related viruses were closely related to ssDNA mycoviruses that infect plant-pathogenic fungi. Phylogenetic analysis based on the replication initiator protein sequence indicated that the airborne ssDNA viruses were distantly related to known ssDNA viruses, suggesting that a high diversity of viruses were newly discovered. This research is the first to report the seasonality of airborne viruses and their genetic diversity, which enhances our understanding of viral ecology in temperate regions. PMID:22623790

Centripetal and centrifugal forces in the moral circle: Competing constraints on moral learning.

PubMed

Graham, Jesse; Waytz, Adam; Meindl, Peter; Iyer, Ravi; Young, Liane

2017-10-01

The idea of the moral circle pictures the self in the center, surrounded by concentric circles encompassing increasingly distant possible targets of moral concern, including family, local community, nation, all humans, all mammals, all living things including plants, and all things including inanimate objects. The authors develop the idea of two opposing forces in people's moral circles, with centripetal forces pulling inward, urging greater concern for close others than for distant others, and centrifugal forces pushing outward, resisting "drawing the line" anywhere as a form of prejudice and urging egalitarian concern for all regardless of social distance. Review of the developmental literature shows very early emergence of both moral forces, suggesting at least partly intuitive bases for each. Moral education approaches favoring one force over the other are compared, to show how these forces can provide constraints on moral learning. Finally, the centripetal/centrifugal forces view is applied to current moral debates about empathy and about politics. The authors argue that this view helps us see how intercultural and interpersonal disagreements about morality are based in intrapersonal conflicts shared by all people. Copyright © 2016. Published by Elsevier B.V.

Head and pelvic movement symmetry in horses during circular motion and in rising trot.

PubMed

Robartes, Helen; Fairhurst, Harriet; Pfau, Thilo

2013-12-01

Lameness examinations in horses often include lungeing and ridden exercise. To incorporate these exercises into the evidence-based decision making process aided by quantitative sensor based gait analysis, guideline values for movement asymmetry are needed. In this study, movement symmetry (MS) was quantified in horses during unridden and ridden trot on the straight and on the circle. Systematic changes in MS were expected as a result of the 'asymmetrical loading' caused by circular movement, the rising trot and the combination of the two. Out of 23 horses (age 4-20 years, height 13.3-17.2 hands), 13 presented within normal limits for head movement and 22 for pelvic movement. Inertial measurement units assessed MS of vertical head and sacral movement during trot in-hand, on the lunge and in rising trot (straight, left/right circle). Changes in MS between straight line trot and ridden exercise on the circle were more pronounced for the head than for the sacrum. The highest amount of asymmetry was observed during rising trot on the circle (symmetry index of the head: 1.23 for the left rein, 0.83 for the right rein; symmetry index of the sacrum 0.84 for the left rein, 1.15 for the right rein). Change in MS was significant between exercise conditions except for the difference between head displacement maxima. Horses had greatest asymmetry during rising trot on the circle, with MS values of comparable magnitude to mild lameness. Copyright © 2013 Elsevier Ltd. All rights reserved.

[Urban heat island effect based on urban heat island source and sink indices in Shenyang, Northeast China].

PubMed

Li, Li-Guang; Xu, Shen-Lai; Wang, Hong-Bo; Zhao, Zi-Qi; Cai, Fu; Wu, Jin-Wen; Chen, Peng-Shi; Zhang, Yu-Shu

2013-12-01

Based on the remote images in 2001 and 2010, the source and sink areas of urban heat island (UHI) in Shenyang City, Northeast China were determined by GIS technique. The effect of urban regional landscape pattern on UHI effect was assessed with land surface temperature (LST), area rate index (CI) of the source and sink areas and intensity index (LI) of heat island. The results indicated that the land use type changed significantly from 2001 to 2010, which significantly changed the source and sink areas of UHI, especially in the second and third circle regions. The source and sink areas were 94.3% and 5.7% in the first circle region, 64.0% and 36.0% in the third circle region in 2001, while they were 93.4% and 6.6%, 70.2% and 29.8% in 2010, respectively. It suggested that the land use pattern extended by a round shape in Shenyang led to the corresponding UHI pattern. The LST in the study area tended to decrease from the first circle region to the third. The UHI intensity was characterized with a single center in 2001 and with several centers in 2010, and the grade of UHI intensity was in a decreasing trend from 2001 to 2010. The absolute value of CI increased from the first circle region to the third, and the L1 was close to 1, suggesting the change in land use pattern had no significant influence on UHI in Shenyang.

Accurate airway centerline extraction based on topological thinning using graph-theoretic analysis.

PubMed

Bian, Zijian; Tan, Wenjun; Yang, Jinzhu; Liu, Jiren; Zhao, Dazhe

2014-01-01

The quantitative analysis of the airway tree is of critical importance in the CT-based diagnosis and treatment of popular pulmonary diseases. The extraction of airway centerline is a precursor to identify airway hierarchical structure, measure geometrical parameters, and guide visualized detection. Traditional methods suffer from extra branches and circles due to incomplete segmentation results, which induce false analysis in applications. This paper proposed an automatic and robust centerline extraction method for airway tree. First, the centerline is located based on the topological thinning method; border voxels are deleted symmetrically to preserve topological and geometrical properties iteratively. Second, the structural information is generated using graph-theoretic analysis. Then inaccurate circles are removed with a distance weighting strategy, and extra branches are pruned according to clinical anatomic knowledge. The centerline region without false appendices is eventually determined after the described phases. Experimental results show that the proposed method identifies more than 96% branches and keep consistency across different cases and achieves superior circle-free structure and centrality.

Quantifying oil filtration effects on bearing life

NASA Technical Reports Server (NTRS)

Needelman, William M.; Zaretsky, Erwin V.

1991-01-01

Rolling-element bearing life is influenced by the number, size, and material properties of particles entering the Hertzian contact of the rolling element and raceway. In general, rolling-element bearing life increases with increasing level of oil filtration. Based upon test results, two equations are presented which allow for the adjustment of bearing L(sub 10) or catalog life based upon oil filter rating. It is recommended that where no oil filtration is used catalog life be reduced by 50 percent.

75 FR 34213 - Solicitation of Applications and Notice of Funding Availability for the FRA Railroad System...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-16

... of Bio-based Technologies (Lubricants) that can be used in locomotives, rolling stock and other rail... of the Use of Bio-based Technologies (Lubricants) that can be used in locomotives, rolling stock and...

Microfluidic magnetic fluidized bed for DNA analysis in continuous flow mode.

PubMed

Hernández-Neuta, Iván; Pereiro, Iago; Ahlford, Annika; Ferraro, Davide; Zhang, Qiongdi; Viovy, Jean-Louis; Descroix, Stéphanie; Nilsson, Mats

2018-04-15

Magnetic solid phase substrates for biomolecule manipulation have become a valuable tool for simplification and automation of molecular biology protocols. However, the handling of magnetic particles inside microfluidic chips for miniaturized assays is often challenging due to inefficient mixing, aggregation, and the advanced instrumentation required for effective actuation. Here, we describe the use of a microfluidic magnetic fluidized bed approach that enables dynamic, highly efficient and simplified magnetic bead actuation for DNA analysis in a continuous flow platform with minimal technical requirements. We evaluate the performance of this approach by testing the efficiency of individual steps of a DNA assay based on padlock probes and rolling circle amplification. This assay comprises common nucleic acid analysis principles, such as hybridization, ligation, amplification and restriction digestion. We obtained efficiencies of up to 90% for these reactions with high throughput processing up to 120μL of DNA dilution at flow rates ranging from 1 to 5μL/min without compromising performance. The fluidized bed was 20-50% more efficient than a commercially available solution for microfluidic manipulation of magnetic beads. Moreover, to demonstrate the potential of this approach for integration into micro-total analysis systems, we optimized the production of a low-cost polymer based microarray and tested its analytical performance for integrated single-molecule digital read-out. Finally, we provide the proof-of-concept for a single-chamber microfluidic chip that combines the fluidized bed with the polymer microarray for a highly simplified and integrated magnetic bead-based DNA analyzer, with potential applications in diagnostics. Copyright © 2017 Elsevier B.V. All rights reserved.

A unique dual recognition hairpin probe mediated fluorescence amplification method for sensitive detection of uracil-DNA glycosylase and endonuclease IV activities.

PubMed

Wu, Yushu; Yan, Ping; Xu, Xiaowen; Jiang, Wei

2016-03-07

Uracil-DNA glycosylase (UDG) and endonuclease IV (Endo IV) play cooperative roles in uracil base-excision repair (UBER) and inactivity of either will interrupt the UBER to cause disease. Detection of UDG and Endo IV activities is crucial to evaluate the UBER process in fundamental research and diagnostic application. Here, a unique dual recognition hairpin probe mediated fluorescence amplification method was developed for sensitively and selectively detecting UDG and Endo IV activities. For detecting UDG activity, the uracil base in the probe was excised by the target enzyme to generate an apurinic/apyrimidinic (AP) site, achieving the UDG recognition. Then, the AP site was cleaved by a tool enzyme Endo IV, releasing a primer to trigger rolling circle amplification (RCA) reaction. Finally, the RCA reaction produced numerous repeated G-quadruplex sequences, which interacted with N-methyl-mesoporphyrin IX to generate an enhanced fluorescence signal. Alternatively, for detecting Endo IV activity, the uracil base in the probe was first converted into an AP site by a tool enzyme UDG. Next, the AP site was cleaved by the target enzyme, achieving the Endo IV recognition. The signal was then generated and amplified in the same way as those in the UDG activity assay. The detection limits were as low as 0.00017 U mL(-1) for UDG and 0.11 U mL(-1) for Endo IV, respectively. Moreover, UDG and Endo IV can be well distinguished from their analogs. This method is beneficial for properly evaluating the UBER process in function studies and disease prognoses.

Performance Degradation Assessment of Rolling Element Bearings using Improved Fuzzy Entropy

NASA Astrophysics Data System (ADS)

Zhu, Keheng; Jiang, Xiaohui; Chen, Liang; Li, Haolin

2017-10-01

Rolling element bearings are an important unit in the rotating machines, and their performance degradation assessment is the basis of condition-based maintenance. Targeting the non-linear dynamic characteristics of faulty signals of rolling element bearings, a bearing performance degradation assessment approach based on improved fuzzy entropy (FuzzyEn) is proposed in this paper. FuzzyEn has less dependence on data length and achieves more freedom of parameter selection and more robustness to noise. However, it neglects the global trend of the signal when calculating similarity degree of two vectors, and thus cannot reflect the running state of the rolling element bearings accurately. Based on this consideration, the algorithm of FuzzyEn is improved in this paper and the improved FuzzyEn is utilized as an indicator for bearing performance degradation evaluation. The vibration data from run-to-failure test of rolling element bearings are used to validate the proposed method. The experimental results demonstrate that, compared with the traditional kurtosis and root mean square, the proposed method can detect the incipient fault in advance and can reflect the whole performance degradation process more clearly.

A robust observer based on H∞ filtering with parameter uncertainties combined with Neural Networks for estimation of vehicle roll angle

NASA Astrophysics Data System (ADS)

Boada, Beatriz L.; Boada, Maria Jesus L.; Vargas-Melendez, Leandro; Diaz, Vicente

2018-01-01

Nowadays, one of the main objectives in road transport is to decrease the number of accident victims. Rollover accidents caused nearly 33% of all deaths from passenger vehicle crashes. Roll Stability Control (RSC) systems prevent vehicles from untripped rollover accidents. The lateral load transfer is the main parameter which is taken into account in the RSC systems. This parameter is related to the roll angle, which can be directly measured from a dual-antenna GPS. Nevertheless, this is a costly technique. For this reason, roll angle has to be estimated. In this paper, a novel observer based on H∞ filtering in combination with a neural network (NN) for the vehicle roll angle estimation is proposed. The design of this observer is based on four main criteria: to use a simplified vehicle model, to use signals of sensors which are installed onboard in current vehicles, to consider the inaccuracy in the system model and to attenuate the effect of the external disturbances. Experimental results show the effectiveness of the proposed observer.

EFFICACY OF THE 20-WEEK CIRCLE OF SECURITY INTERVENTION: CHANGES IN CAREGIVER REFLECTIVE FUNCTIONING, REPRESENTATIONS, AND CHILD ATTACHMENT IN AN AUSTRALIAN CLINICAL SAMPLE.

PubMed

Huber, Anna; McMahon, Catherine A; Sweller, Naomi

2015-01-01

Circle of Security is an attachment theory based intervention that aims to promote secure parent-child attachment relationships. Despite extensive uptake of the approach, there is limited empirical evidence regarding efficacy. The current study examined whether participation in the 20-week Circle of Security intervention resulted in positive caregiver-child relationship change in four domains: caregiver reflective functioning; caregiver representations of the child and the relationship with the child; child attachment security, and attachment disorganization. Archived pre- and postintervention data were analyzed from 83 clinically referred caregiver-child dyads (child age: 13-88 months) who completed the Circle of Security intervention in sequential cohorts and gave permission for their data to be included in the study. Caregivers completed the Circle of Security Interview, and dyads were filmed in the Strange Situation Procedure before and after the intervention. Results supported all four hypotheses: Caregiver reflective functioning, caregiving representations, and level of child attachment security increased after the intervention, and level of attachment disorganization decreased for those with high baseline levels. Those whose scores were least optimal prior to intervention showed the greatest change in all domains. This study adds to the evidence suggesting that the 20-week Circle of Security intervention results in significant relationship improvements for caregivers and their children. © 2015 Michigan Association for Infant Mental Health.

Coloring your information: How designers use Theory of Color in creative ways to present infographic

NASA Astrophysics Data System (ADS)

Lucius, C. R.; Fuad, A.

2017-12-01

Various methods of data presentation is now visualized through engaging infographics and perform the presentation techniques a new kind of storytelling. Geometric elements for infographics perform interesting data, which is developed with color harmony. There are categories of colors based on color circle from the theory of color design: primary color, secondary color and tertiary color. This color circle allows a designer to visualize the balance and harmony of colors when they are side by side. These composition of colors can be formed as a harmonious dyad, triad, or tetrads. A harmonious dyad is formed from two diametrically opposed colors on the color circle, which known as contrast complementary and works best in color harmonious if one of the colors is dominant. A harmonious triad is represented by three colors from the color circle which positions with an equilateral triangle. An triangle of yellow-red-blue shows the most powerful of harmonious triad and call as the fundamental triad. A harmonious tetrad is developed from two pairs of complementary colors, which can be formed by rectangle or square on the color circle. It help to figure out how objects are connected on presenting data. To create an efficiency infographic, presenting data has to prepare with some strategic. The color circle has the power to perform the infographic when it is made for a fascinating design.

Supersonic aerodynamic characteristics of a maneuvering canard-controlled missile with fixed and free-rolling tail fins

NASA Technical Reports Server (NTRS)

Blair, A. B., Jr.

1990-01-01

Wind tunnel investigations were conducted on a generic cruciform canard-controlled missile configuration. The model featured fixed or free-rolling tail-fin afterbodies to provide an expanded aerodynamic data base with particular emphasis on alleviating large induced rolling moments and/or for providing canard roll control throughout the entire test angle-of-attack range. The tests were conducted in the NASA Langley Unitary Plan Wind Tunnel at Mach numbers from 2.50 to 3.50 at a constant Reynolds number per foot of 2.00 x 10 to the 6th. Selected test results are presented to show the effects of a fixed or free-rolling tail-fin afterbody on the static longitudinal and lateral-directional aerodynamic characteristics of a canard-controlled missile with pitch, yaw, and roll control at model roll angles of 0 deg and 45 deg.

Hot-rolling of reduced activation 8CrODS ferritic steel

NASA Astrophysics Data System (ADS)

Wu, Xiaochao; Ukai, Shigeharu; Leng, Bin; Oono, Naoko; Hayashi, Shigenari; Sakasegawa, Hideo; Tanigawa, Hiroyasu

2013-11-01

The 8CrODS ferritic steel is based on J1-lot developed for the advanced fusion blanket material to increase the coolant outlet temperature. A hot-rolling was conducted at the temperature above Ar3 of 716 °C, and its effect on the microstructure and tensile strength in 8CrODS ferritic steel was evaluated, comparing together with normalized and tempered specimen. It was confirmed that hot-rolling leads to slightly increased fraction of the ferrite and highly improved tensile strength. This ferrite was formed by transformation from the hot-rolled austenite during cooling due to fine austenite grains induced by hot-rolling. The coarsening of the transformed ferrite in hot-rolled specimen can be attributed to the crystalline rotation and coalescence of the similar oriented grains. The improved strength of hot-rolled specimen was ascribed to the high dislocation density and replacement of easily deformed martensite with the transformed coarse ferrite.

Application of double laser interferometer in the measurement of translational stages' roll characteristics

NASA Astrophysics Data System (ADS)

Jin, Tao; Shen, Lu; Ke, Youlong; Hou, Wenmei; Ju, Aisong; Yang, Wei; Luo, Jialin

2016-10-01

In order to achieve rapid measurement of larger travel translation stages' roll-angle error in industry and to study the roll characteristics, this paper designs a small roll-angle measurement system based on laser heterodyne interferometry technology, test and researched on the roll characteristics of ball screw linear translation stage to fill the blank of the market. The results show that: during the operation of the ball screw linear translation stage, the workbench's roll angle changes complexly, its value is not only changing with different positions, but also shows different levels of volatility, what's more, the volatility varies with the workbench's work speed . Because of the non uniform stiffness of ball screw, at the end of each movement, the elastic potential energy being stored from the working process should release slowly, and the workbench will cost a certain time to roll fluctuate before it achieves a stable tumbling again.

Static roll-tilt over 5 minutes locally distorts the internal estimate of direction of gravity.

PubMed

Tarnutzer, A A; Bockisch, C J; Straumann, D; Marti, S; Bertolini, G

2014-12-01

The subjective visual vertical (SVV) indicates perceived direction of gravity. Even in healthy human subjects, roll angle-dependent misestimations, roll overcompensation (A-effect, head-roll > 60° and <135°) and undercompensation (E-effect, head-roll < 60°), occur. Previously, we demonstrated that, after prolonged roll-tilt, SVV estimates when upright are biased toward the preceding roll position, which indicates that perceived vertical (PV) is shifted by the prior tilt (Tarnutzer AA, Bertolini G, Bockisch CJ, Straumann D, Marti S. PLoS One 8: e78079, 2013). Hypothetically, PV in any roll position could be biased toward the previous roll position. We asked whether such a "global" bias occurs or whether the bias is "local". The SVV of healthy human subjects (N = 9) was measured in nine roll positions (-120° to +120°, steps = 30°) after 5 min of roll-tilt in one of two adaptation positions (±90°) and compared with control trials without adaptation. After adapting, adjustments were shifted significantly (P < 0.05) toward the previous adaptation position for nearby roll-tilted positions (±30°, ±60°) and upright only. We computationally simulated errors based on the sum of a monotonically increasing function (producing roll undercompensation) and a mixture of Gaussian functions (representing roll overcompensation centered around PV). In combination, the pattern of A- and E-effects could be generated. By shifting the function representing local overcompensation toward the adaptation position, the experimental postadaptation data could be fitted successfully. We conclude that prolonged roll-tilt locally distorts PV rather than globally shifting it. Short-term adaptation of roll overcompensation may explain these shifts and could reflect the brain's strategy to optimize SVV estimates around recent roll positions. Thus postural stability can be improved by visually-mediated compensatory responses at any sustained body-roll orientation. Copyright © 2014 the American Physiological Society.

Rolling bearing fault detection and diagnosis based on composite multiscale fuzzy entropy and ensemble support vector machines

NASA Astrophysics Data System (ADS)

Zheng, Jinde; Pan, Haiyang; Cheng, Junsheng

2017-02-01

To timely detect the incipient failure of rolling bearing and find out the accurate fault location, a novel rolling bearing fault diagnosis method is proposed based on the composite multiscale fuzzy entropy (CMFE) and ensemble support vector machines (ESVMs). Fuzzy entropy (FuzzyEn), as an improvement of sample entropy (SampEn), is a new nonlinear method for measuring the complexity of time series. Since FuzzyEn (or SampEn) in single scale can not reflect the complexity effectively, multiscale fuzzy entropy (MFE) is developed by defining the FuzzyEns of coarse-grained time series, which represents the system dynamics in different scales. However, the MFE values will be affected by the data length, especially when the data are not long enough. By combining information of multiple coarse-grained time series in the same scale, the CMFE algorithm is proposed in this paper to enhance MFE, as well as FuzzyEn. Compared with MFE, with the increasing of scale factor, CMFE obtains much more stable and consistent values for a short-term time series. In this paper CMFE is employed to measure the complexity of vibration signals of rolling bearings and is applied to extract the nonlinear features hidden in the vibration signals. Also the physically meanings of CMFE being suitable for rolling bearing fault diagnosis are explored. Based on these, to fulfill an automatic fault diagnosis, the ensemble SVMs based multi-classifier is constructed for the intelligent classification of fault features. Finally, the proposed fault diagnosis method of rolling bearing is applied to experimental data analysis and the results indicate that the proposed method could effectively distinguish different fault categories and severities of rolling bearings.

A model for prediction of the transient rolling resistance of tyres based on inner-liner temperatures

NASA Astrophysics Data System (ADS)

Greiner, Matthias; Unrau, Hans-Joachim; Gauterin, Frank

2018-01-01

Measurements of rolling resistance in thermal equilibrium of a tyre, like measurements according to ISO 28580, do not allow statements about rolling resistances under other driving conditions. Such statements, however, are necessary to determine the energy consumption in driving cycles. Especially for the proper calculation of electric-vehicle remaining ranges and the selection of the respective driving strategies, the real amount of energy consumption is required. This paper presents a model approach, which by means of only one standardised rolling resistance measurement can be parameterised and, considering the present driving speed and tyre temperature, can predict the respective current rolling resistance.

The Influence of Hot-Rolled Temperature on Plasma Nitriding Behavior of Iron-Based Alloys

NASA Astrophysics Data System (ADS)

El-Hossary, F. M.; Khalil, S. M.; Lotfy, Kh.; Kassem, M. A.

2009-07-01

Experiments were performed with an aim of studying the effect of hot-rolled temperature (600 and 900°C) on radio frequency (rf) plasma nitriding of Fe93Ni4Zr3 alloy. Nitriding was carried out for 10 min in a nitrogen atmosphere at a base pressure of 10-2 mbarr. Different continuous plasma processing powers of 300-550 W in steps 50 W or less were applied. Nitrided hot-rolled specimens were characterized by optical microscopy (OM), X-ray diffraction (XRD) and microhardness measurements. The results reveal that the surface of hot-rolled rf plasma nitrided specimens at 600°C is characterized with a fine microstructure as a result of the high nitrogen solubility and diffusivity. Moreover, the hot-rolled treated samples at 600°C exhibit higher microhardness value than the associated values of hot-rolled treated samples at 900°C. The enhancement of microhardness is due to precipitation and predominance of new phases ( γ and ɛ phases). Mainly, this conclusion has been attributed to the high defect densities and small grain sizes of the samples hot-rolled at 600°C. Generally, the refinement of grain size plays a dramatic role in improvement of mechanical properties of tested samples.

A comparative study of roll compaction of free-flowing and cohesive pharmaceutical powders.

PubMed

Yu, Shen; Gururajan, Bindhu; Reynolds, Gavin; Roberts, Ron; Adams, Michael J; Wu, Chuan-Yu

2012-05-30

Roll compaction is widely adopted as a dry granulation method in the pharmaceutical industry. The roll compaction behaviour of feed powders is primarily governed by two parameters: the maximum pressure and the nip angle. Although the maximum pressure can be measured directly using pressure sensors fitted in the rolls, it is not a trivial task to determine the nip angle, which is a measure of the size of the compaction zone and hence the degree of compression. Thus a robust approach based upon the calculation of the pressure gradient, which can be obtained directly from experiments using an instrumented roll compactor, was developed. It has been shown that the resulting nip angles are comparable to those obtained using the methods reported in literature. Nevertheless, the proposed approach has distinctive advantages including (1) it is based on the intrinsic features of slip and no-slip interactions between the powder and roll surface and (2) it is not necessary to carry out wall friction measurements that involve plates that may not be representative of the roll compactor in terms of the surface topography and surface energy. The method was evaluated by investigating the effect of roll speed for two pharmaceutical excipients with distinctive material properties: microcrystalline cellulose (MCC) and di-calcium phosphate dihydrate (DCPD). It was found that the maximum pressure and nip angle for DCPD, which is a cohesive powder, decrease sharply with increasing roll speed whereas they are essentially independent of roll speed for MCC, which is an easy flowing powder. The roll compaction behaviour of MCC-DCPD mixtures with various compositions was also investigated in order to evaluate the effect of flowability. It was found that the nip angle and maximum pressure generally increased with improved flowability of the feed powders. Copyright © 2012 Elsevier B.V. All rights reserved.

Roll Casting of Aluminum Alloy Clad Strip

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

Nakamura, R.; Tsuge, H.; Haga, T.

2011-01-17

Casting of aluminum alloy three layers of clad strip was tried using the two sets of twin roll casters, and effects of the casting parameters on the cladding conditions were investigated. One twin roll caster was mounted on the other twin roll caster. Base strip was 8079 aluminum alloy and overlay strips were 6022 aluminum alloy. Effects of roll-load of upper and lower casters and melt temperature of the lower caster were investigated. When the roll-load of the upper and lower caster was large enough, the overlay strip could be solidified and be connected. The overlay strip could be connectedmore » when the melt of the overlay strip cast by the lower caster was low enough. Sound three layers of clad strip could be cast by proper conditions.« less

78 FR 12255 - Airworthiness Directives; Rolls-Royce (1971) Limited, Bristol Engine Division Turbojet Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-22

...: (202) 493-2251. For service information identified in this AD, contact Rolls-Royce plc, Corporate... received by the closing date and may amend this proposed AD based on those comments. We will post all... this AD, contact Rolls-Royce plc, Corporate Communications, P.O. Box 31, Derby, England, DE248BJ; phone...

76 FR 47550 - Certain Tissue Paper Products From the People's Republic of China: Notice of Rescission of the...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-05

... products produced from Chinese-origin jumbo rolls/ sheets.\\3\\ We determined in the Preliminary Results, as... paper products produced using Chinese-origin jumbo rolls/sheets. Further, based on AFA, we preliminarily... produced by MFVN from Chinese-origin jumbo rolls/sheets is China. Consequently, we assigned MFVN a cash...

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.

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.

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

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.

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.

Steel Alloy Hot Roll Simulations and Through-Thickness Variation Using Dislocation Density-Based Modeling

NASA Astrophysics Data System (ADS)

Jansen Van Rensburg, G. J.; Kok, S.; Wilke, D. N.

2017-10-01

Different roll pass reduction schedules have different effects on the through-thickness properties of hot-rolled metal slabs. In order to assess or improve a reduction schedule using the finite element method, a material model is required that captures the relevant deformation mechanisms and physics. The model should also report relevant field quantities to assess variations in material state through the thickness of a simulated rolled metal slab. In this paper, a dislocation density-based material model with recrystallization is presented and calibrated on the material response of a high-strength low-alloy steel. The model has the ability to replicate and predict material response to a fair degree thanks to the physically motivated mechanisms it is built on. An example study is also presented to illustrate the possible effect different reduction schedules could have on the through-thickness material state and the ability to assess these effects based on finite element simulations.

Enhancing roll stability of heavy vehicle by LQR active anti-roll bar control using electronic servo-valve hydraulic actuators

NASA Astrophysics Data System (ADS)

Vu, Van Tan; Sename, Olivier; Dugard, Luc; Gaspar, Peter

2017-09-01

Rollover of heavy vehicle is an important road safety problem world-wide. Although rollovers are relatively rare events, they are usually deadly accidents when they occur. The roll stability loss is the main cause of rollover accidents in which heavy vehicles are involved. In order to improve the roll stability, most of modern heavy vehicles are equipped with passive anti-roll bars to reduce roll motion during cornering or riding on uneven roads. However these may be not sufficient to overcome critical situations. This paper introduces the active anti-roll bars made of four electronic servo-valve hydraulic actuators, which are modelled and integrated in a yaw-roll model of a single unit heavy vehicle. The control signal is the current entering the electronic servo-valve and the output is the force generated by the hydraulic actuator. The active control design is achieved solving a linear optimal control problem based on the linear quadratic regulator (LQR) approach. A comparison of several LQR controllers is provided to allow for tackling the considered multi-objective problems. Simulation results in frequency and time domains show that the use of two active anti-roll bars (front and rear axles) drastically improves the roll stability of the single unit heavy vehicle compared with the passive anti-roll bar.

Impact of vertical wind shear on roll structure in idealized hurricane boundary layers

NASA Astrophysics Data System (ADS)

Wang, Shouping; Jiang, Qingfang

2017-03-01

Quasi-two-dimensional roll vortices are frequently observed in hurricane boundary layers. It is believed that this highly coherent structure, likely caused by the inflection-point instability, plays an important role in organizing turbulent transport. Large-eddy simulations are conducted to investigate the impact of wind shear characteristics, such as the shear strength and inflection-point level, on the roll structure in terms of its spectral characteristics and turbulence organization. A mean wind nudging approach is used in the simulations to maintain the specified mean wind shear without directly affecting turbulent motions. Enhancing the radial wind shear expands the roll horizontal scale and strengthens the roll's kinetic energy. Increasing the inflection-point level tends to produce a narrow and sharp peak in the power spectrum at the wavelength consistent with the roll spacing indicated by the instantaneous turbulent fields. The spectral tangential momentum flux, in particular, reaches a strong peak value at the roll wavelength. In contrast, the spectral radial momentum flux obtains its maximum at the wavelength that is usually shorter than the roll's, suggesting that the roll radial momentum transport is less efficient than the tangential because of the quasi-two-dimensionality of the roll structure. The most robust rolls are produced in a simulation with the highest inflection-point level and relatively strong radial wind shear. Based on the spectral analysis, the roll-scale contribution to the turbulent momentum flux can reach 40 % in the middle of the boundary layer.

E-selectin ligand-1 controls circulating prostate cancer cell rolling/adhesion and metastasis

PubMed Central

Yasmin-Karim, Sayeda; King, Michael R.; Messing, Edward M.; Lee, Yi-Fen

2014-01-01

Circulating prostate cancer (PCa) cells preferentially roll and adhere on bone marrow vascular endothelial cells, where abundant E-selectin and stromal cell-derived factor 1 (SDF-1) are expressed, subsequently initiating a cascade of activation events that eventually lead to the development of metastases. To elucidate the roles of circulating PCa cells' rolling and adhesion behaviors in cancer metastases, we applied a dynamic cylindrical flow-based microchannel device that is coated with E-selectin and SDF-1, mimicking capillary endothelium. Using this device we captured a small fraction of rolling PCa cells. These rolling cells display higher static adhesion ability, more aggressive cancer phenotypes and stem-like properties. Importantly, mice received rolling PCa cells, but not floating PCa cells, developed cancer metastases. Genes coding for E-selectin ligands and genes associated with cancer stem cells and metastasis were elevated in rolling PCa cells. Knock down of E-selectin ligand 1(ESL-1), significantly impaired PCa cells' rolling capacity and reduced cancer aggressiveness. Moreover, ESL-1 activates RAS and MAP kinase signal cascade, consequently inducing the downstream targets. In summary, circulating PCa cells' rolling capacity contributes to PCa metastasis, and that is in part controlled by ESL-1. PMID:25301730

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.

Rolling bearing fault diagnosis based on information fusion using Dempster-Shafer evidence theory

NASA Astrophysics Data System (ADS)

Pei, Di; Yue, Jianhai; Jiao, Jing

2017-10-01

This paper presents a fault diagnosis method for rolling bearing based on information fusion. Acceleration sensors are arranged at different position to get bearing vibration data as diagnostic evidence. The Dempster-Shafer (D-S) evidence theory is used to fuse multi-sensor data to improve diagnostic accuracy. The efficiency of the proposed method is demonstrated by the high speed train transmission test bench. The results of experiment show that the proposed method in this paper improves the rolling bearing fault diagnosis accuracy compared with traditional signal analysis methods.

Data-based hybrid tension estimation and fault diagnosis of cold rolling continuous annealing processes.

PubMed

Liu, Qiang; Chai, Tianyou; Wang, Hong; Qin, Si-Zhao Joe

2011-12-01

The continuous annealing process line (CAPL) of cold rolling is an important unit to improve the mechanical properties of steel strips in steel making. In continuous annealing processes, strip tension is an important factor, which indicates whether the line operates steadily. Abnormal tension profile distribution along the production line can lead to strip break and roll slippage. Therefore, it is essential to estimate the whole tension profile in order to prevent the occurrence of faults. However, in real annealing processes, only a limited number of strip tension sensors are installed along the machine direction. Since the effects of strip temperature, gas flow, bearing friction, strip inertia, and roll eccentricity can lead to nonlinear tension dynamics, it is difficult to apply the first-principles induced model to estimate the tension profile distribution. In this paper, a novel data-based hybrid tension estimation and fault diagnosis method is proposed to estimate the unmeasured tension between two neighboring rolls. The main model is established by an observer-based method using a limited number of measured tensions, speeds, and currents of each roll, where the tension error compensation model is designed by applying neural networks principal component regression. The corresponding tension fault diagnosis method is designed using the estimated tensions. Finally, the proposed tension estimation and fault diagnosis method was applied to a real CAPL in a steel-making company, demonstrating the effectiveness of the proposed method.

Printed polymer photonic devices for optical interconnect systems

NASA Astrophysics Data System (ADS)

Subbaraman, Harish; Pan, Zeyu; Zhang, Cheng; Li, Qiaochu; Guo, L. J.; Chen, Ray T.

2016-03-01

Polymer photonic device fabrication usually relies on the utilization of clean-room processes, including photolithography, e-beam lithography, reactive ion etching (RIE) and lift-off methods etc, which are expensive and are limited to areas as large as a wafer. Utilizing a novel and a scalable printing process involving ink-jet printing and imprinting, we have fabricated polymer based photonic interconnect components, such as electro-optic polymer based modulators and ring resonator switches, and thermo-optic polymer switch based delay networks and demonstrated their operation. Specifically, a modulator operating at 15MHz and a 2-bit delay network providing up to 35.4ps are presented. In this paper, we also discuss the manufacturing challenges that need to be overcome in order to make roll-to-roll manufacturing practically viable. We discuss a few manufacturing challenges, such as inspection and quality control, registration, and web control, that need to be overcome in order to realize true implementation of roll-to-roll manufacturing of flexible polymer photonic systems. We have overcome these challenges, and currently utilizing our inhouse developed hardware and software tools, <10μm alignment accuracy at a 5m/min is demonstrated. Such a scalable roll-to-roll manufacturing scheme will enable the development of unique optoelectronic devices which can be used in a myriad of different applications, including communication, sensing, medicine, security, imaging, energy, lighting etc.

Flows in forward deformable roll coating gaps: Comparison between spring and plane-strain models of roll cover

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

Carvalho, M.S.; Scriven, L.E.

1997-12-01

In this report the flow between rigid and a deformable rotating rolls fully submerged in a liquid pool is studied. The deformation of compliant roll cover is described by two different models (1) independent, radially oriented springs that deform in response to the traction force applied at the extremity of each or one-dimensional model, and (2) a plane-strain deformation of an incompressible Mooney-Rivlin material or non-linear elastic model. Based on the flow rate predictions of both models, an empirical relation between the spring constant of the one dimensional model and the roll cover thickness and elastic modulus is proposed.

A Simplified Finite Element Simulation for Straightening Process of Thin-Walled Tube

NASA Astrophysics Data System (ADS)

Zhang, Ziqian; Yang, Huilin

2017-12-01

The finite element simulation is an effective way for the study of thin-walled tube in the two cross rolls straightening process. To determine the accurate radius of curvature of the roll profile more efficiently, a simplified finite element model based on the technical parameters of an actual two cross roll straightening machine, was developed to simulate the complex straightening process. Then a dynamic simulation was carried out using ANSYS LS-DYNA program. The result implied that the simplified finite element model was reasonable for simulate the two cross rolls straightening process, and can be obtained the radius of curvature of the roll profile with the tube’s straightness 2 mm/m.

Fault Diagnosis for Rolling Bearings under Variable Conditions Based on Visual Cognition

PubMed Central

Cheng, Yujie; Zhou, Bo; Lu, Chen; Yang, Chao

2017-01-01

Fault diagnosis for rolling bearings has attracted increasing attention in recent years. However, few studies have focused on fault diagnosis for rolling bearings under variable conditions. This paper introduces a fault diagnosis method for rolling bearings under variable conditions based on visual cognition. The proposed method includes the following steps. First, the vibration signal data are transformed into a recurrence plot (RP), which is a two-dimensional image. Then, inspired by the visual invariance characteristic of the human visual system (HVS), we utilize speed up robust feature to extract fault features from the two-dimensional RP and generate a 64-dimensional feature vector, which is invariant to image translation, rotation, scaling variation, etc. Third, based on the manifold perception characteristic of HVS, isometric mapping, a manifold learning method that can reflect the intrinsic manifold embedded in the high-dimensional space, is employed to obtain a low-dimensional feature vector. Finally, a classical classification method, support vector machine, is utilized to realize fault diagnosis. Verification data were collected from Case Western Reserve University Bearing Data Center, and the experimental result indicates that the proposed fault diagnosis method based on visual cognition is highly effective for rolling bearings under variable conditions, thus providing a promising approach from the cognitive computing field. PMID:28772943

Transient thermal stresses of work roll by coupled thermoelasticity

NASA Astrophysics Data System (ADS)

Lai, W. B.; Chen, T. C.; Weng, C. I.

1991-01-01

A numerical method, based on a two-dimensional plane strain model, is developed to predict the transient responses (that include distributions of temperature, thermal deformation, and thermal stress) of work roll during strip rolling by coupled thermoelasticity. The method consists of discretizing the space domain of the problem by finite element method first, and then treating the time domain by implicit time integration techniques. In order to avoid the difficulty in analysis due to relative movement between work roll and its thermal boundary, the energy equation is formulated with respect to a fixed Eulerian reference frame. The effect of thermoelastic coupling term, that is generally disregarded in strip rolling, can be considered and assessed. The influences of some important process parameters, such as rotational speed of the roll and intensity of heat flux, on transient solutions are also included and discussed. Furthermore, since the stress history at any point of the roll in both transient and steady state could be accurately evaluated, it is available to perform the analysis of thermal fatigue for the roll by means of previous data.

Effect of rolling on the high temperature tensile and stress-rupture properties of tungsten fiber-superalloy composites

NASA Technical Reports Server (NTRS)

Petrasek, D. W.

1974-01-01

An investigation was conducted to determine the effects of mechanical working on the 1093 C (2000 F) tensile and stress-rupture strength of tungsten alloy/superalloy composites. Hot pressed composites containing either conventional tungsten lamp filament wire or tungsten-1% ThO2 wire and a nickel base alloy matrix were hot rolled at 1093 C (2000 F). The hot pressed and rolled composite specimens were then tested in tension and stress-rupture at 1093 C (2000 F). Rolling decreased the degree of fiber-matrix reaction as a function of time of exposure at 1093 C (2000 F). The stress-rupture properties of the rolled composites were superior to hot pressed composites containing equivalent diameter fibers. Rolling did not appreciably affect the 1093 C (2000 F) ultimate tensile strength of the composites.

Calendering and Rolling of Viscoplastic Materials: Theory and Experiments

NASA Astrophysics Data System (ADS)

Mitsoulis, E.; Sofou, S.; Muliawan, E. B.; Hatzikiriakos, S. G.

2007-04-01

The calendering and rolling processes are used in a wide variety of industries for the production of rolled sheets or films of specific thickness and final appearance. The acquired final sheet thickness depends mainly on the rheological properties of the material. Materials which have been used in the present study are foodstuff (such as mozzarella cheese and flour-water dough) used in food processing. These materials are rheologically viscoplastic, obeying the Herschel-Bulkley model. The results give the final sheet thickness and the torque as a function of the roll speed. Theoretical analysis based on the Lubrication Approximation Theory (LAT) shows that LAT is a good predictive tool for calendering, where the sheet thickness is very small compared with the roll size. However, in rolling where this is not true, LAT does not hold, and a 2-D analysis is necessary.

Mathematical-Artificial Neural Network Hybrid Model to Predict Roll Force during Hot Rolling of Steel

NASA Astrophysics Data System (ADS)

Rath, S.; Sengupta, P. P.; Singh, A. P.; Marik, A. K.; Talukdar, P.

2013-07-01

Accurate prediction of roll force during hot strip rolling is essential for model based operation of hot strip mills. Traditionally, mathematical models based on theory of plastic deformation have been used for prediction of roll force. In the last decade, data driven models like artificial neural network have been tried for prediction of roll force. Pure mathematical models have accuracy limitations whereas data driven models have difficulty in convergence when applied to industrial conditions. Hybrid models by integrating the traditional mathematical formulations and data driven methods are being developed in different parts of world. This paper discusses the methodology of development of an innovative hybrid mathematical-artificial neural network model. In mathematical model, the most important factor influencing accuracy is flow stress of steel. Coefficients of standard flow stress equation, calculated by parameter estimation technique, have been used in the model. The hybrid model has been trained and validated with input and output data collected from finishing stands of Hot Strip Mill, Bokaro Steel Plant, India. It has been found that the model accuracy has been improved with use of hybrid model, over the traditional mathematical model.

Content-aware photo collage using circle packing.

PubMed

Yu, Zongqiao; Lu, Lin; Guo, Yanwen; Fan, Rongfei; Liu, Mingming; Wang, Wenping

2014-02-01

In this paper, we present a novel approach for automatically creating the photo collage that assembles the interest regions of a given group of images naturally. Previous methods on photo collage are generally built upon a well-defined optimization framework, which computes all the geometric parameters and layer indices for input photos on the given canvas by optimizing a unified objective function. The complex nonlinear form of optimization function limits their scalability and efficiency. From the geometric point of view, we recast the generation of collage as a region partition problem such that each image is displayed in its corresponding region partitioned from the canvas. The core of this is an efficient power-diagram-based circle packing algorithm that arranges a series of circles assigned to input photos compactly in the given canvas. To favor important photos, the circles are associated with image importances determined by an image ranking process. A heuristic search process is developed to ensure that salient information of each photo is displayed in the polygonal area resulting from circle packing. With our new formulation, each factor influencing the state of a photo is optimized in an independent stage, and computation of the optimal states for neighboring photos are completely decoupled. This improves the scalability of collage results and ensures their diversity. We also devise a saliency-based image fusion scheme to generate seamless compositive collage. Our approach can generate the collages on nonrectangular canvases and supports interactive collage that allows the user to refine collage results according to his/her personal preferences. We conduct extensive experiments and show the superiority of our algorithm by comparing against previous methods.

A Benders based rolling horizon algorithm for a dynamic facility location problem

DOE PAGES

Marufuzzaman,, Mohammad; Gedik, Ridvan; Roni, Mohammad S.

2016-06-28

This study presents a well-known capacitated dynamic facility location problem (DFLP) that satisfies the customer demand at a minimum cost by determining the time period for opening, closing, or retaining an existing facility in a given location. To solve this challenging NP-hard problem, this paper develops a unique hybrid solution algorithm that combines a rolling horizon algorithm with an accelerated Benders decomposition algorithm. Extensive computational experiments are performed on benchmark test instances to evaluate the hybrid algorithm’s efficiency and robustness in solving the DFLP problem. Computational results indicate that the hybrid Benders based rolling horizon algorithm consistently offers high qualitymore » feasible solutions in a much shorter computational time period than the standalone rolling horizon and accelerated Benders decomposition algorithms in the experimental range.« less

Architecting Graphene Oxide Rolled-Up Micromotors: A Simple Paper-Based Manufacturing Technology.

PubMed

Baptista-Pires, Luis; Orozco, Jahir; Guardia, Pablo; Merkoçi, Arben

2018-01-01

A graphene oxide rolled-up tube production process is reported using wax-printed membranes for the fabrication of on-demand engineered micromotors at different levels of oxidation, thickness, and lateral dimensions. The resultant graphene oxide rolled-up tubes can show magnetic and catalytic movement within the addition of magnetic nanoparticles or sputtered platinum in the surface of graphene-oxide-modified wax-printed membranes prior to the scrolling process. As a proof of concept, the as-prepared catalytic graphene oxide rolled-up micromotors are successfully exploited for oil removal from water. This micromotor production technology relies on an easy, operator-friendly, fast, and cost-efficient wax-printed paper-based method and may offer a myriad of hybrid devices and applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Models for the Effects of G-seat Cuing on Roll-axis Tracking Performance

NASA Technical Reports Server (NTRS)

Levison, W. H.; Mcmillan, G. R.; Martin, E. A.

1984-01-01

Including whole-body motion in a flight simulator improves performance for a variety of tasks requiring a pilot to compensate for the effects of unexpected disturbances. A possible mechanism for this improvement is that whole-body motion provides high derivative vehicle state information whic allows the pilot to generate more lead in responding to the external disturbances. During development of motion simulating algorithms for an advanced g-cuing system it was discovered that an algorithm based on aircraft roll acceleration producted little or no performance improvement. On the other hand, algorithms based on roll position or roll velocity produced performance equivalent to whole-body motion. The analysis and modeling conducted at both the sensory system and manual control performance levels to explain the above results are described.

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

Miniaturized isothermal nucleic acid amplification, a review.

PubMed

Asiello, Peter J; Baeumner, Antje J

2011-04-21

Micro-Total Analysis Systems (µTAS) for use in on-site rapid detection of DNA or RNA are increasingly being developed. Here, amplification of the target sequence is key to increasing sensitivity, enabling single-cell and few-copy nucleic acid detection. The several advantages to miniaturizing amplification reactions and coupling them with sample preparation and detection on the same chip are well known and include fewer manual steps, preventing contamination, and significantly reducing the volume of expensive reagents. To-date, the majority of miniaturized systems for nucleic acid analysis have used the polymerase chain reaction (PCR) for amplification and those systems are covered in previous reviews. This review provides a thorough overview of miniaturized analysis systems using alternatives to PCR, specifically isothermal amplification reactions. With no need for thermal cycling, isothermal microsystems can be designed to be simple and low-energy consuming and therefore may outperform PCR in portable, battery-operated detection systems in the future. The main isothermal methods as miniaturized systems reviewed here include nucleic acid sequence-based amplification (NASBA), loop-mediated isothermal amplification (LAMP), helicase-dependent amplification (HDA), rolling circle amplification (RCA), and strand displacement amplification (SDA). Also, important design criteria for the miniaturized devices are discussed. Finally, the potential of miniaturization of some new isothermal methods such as the exponential amplification reaction (EXPAR), isothermal and chimeric primer-initiated amplification of nucleic acids (ICANs), signal-mediated amplification of RNA technology (SMART) and others is presented.

Preliminary results from a subsonic high angle-of-attack flush airdata sensing (HI-FADS) system: Design, calibration, and flight test evaluation

NASA Technical Reports Server (NTRS)

Whitmore, Stephen A.; Moes, Timothy R.; Larson, Terry J.

1990-01-01

A nonintrusive high angle-of-attack flush airdata sensing (HI-FADS) system was installed and flight-tested on the F-18 high alpha research flight vehicle. The system is a matrix of 25 pressure orifices in concentric circles on the nose of the vehicle. The orifices determine angles of attack and sideslip, Mach number, and pressure altitude. Pressure was transmitted from the orifices to an electronically scanned pressure module by lines of pneumatic tubing. The HI-FADS system was calibrated and demonstrated using dutch roll flight maneuvers covering large Mach, angle-of-attack, and sideslip ranges. Reference airdata for system calibration were generated by a minimum variance estimation technique blending measurements from two wingtip airdata booms with inertial velocities, aircraft angular rates and attitudes, precision radar tracking, and meteorological analyses. The pressure orifice calibration was based on identifying empirical adjustments to modified Newtonian flow on a hemisphere. Calibration results are presented. Flight test results used all 25 orifices or used a subset of 9 orifices. Under moderate maneuvering conditions, the HI-FADS system gave excellent results over the entire subsonic Mach number range up to 55 deg angle of attack. The internal pneumatic frequency response of the system is accurate to beyond 10 Hz. Aerodynamic lags in the aircraft flow field caused some performance degradation during heavy maneuvering.

A sensitive colorimetric assay system for nucleic acid detection based on isothermal signal amplification technology.

PubMed

Hu, Bo; Guo, Jing; Xu, Ying; Wei, Hua; Zhao, Guojie; Guan, Yifu

2017-08-01

Rapid and accurate detection of microRNAs in biological systems is of great importance. Here, we report the development of a visual colorimetric assay which possesses the high amplification capabilities and high selectivity of the rolling circle amplification (RCA) method and the simplicity and convenience of gold nanoparticles used as a signal indicator. The designed padlock probe recognizes the target miRNA and is circularized, and then acts as the template to extend the target miRNA into a long single-stranded nucleotide chain of many tandem repeats of nucleotide sequences. Next, the RCA product is hybridized with oligonucleotides tagged onto gold nanoparticles. This interaction leads to the aggregation of gold nanoparticles, and the color of the system changes from wine red to dark blue according to the abundance of miRNA. A linear correlation between fluorescence and target oligonucleotide content was obtained in the range 0.3-300 pM, along with a detection limit of 0.13 pM (n = 7) and a RSD of 3.9% (30 pM, n = 9). The present approach provides a simple, rapid, and accurate visual colorimetric assay that allows sensitive biodetection and bioanalysis of DNA and RNA nucleotides of interest in biologically important samples. Graphical abstract The colorimetric assay system for analyzing target oligonucleotides.

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…

Ground roll attenuation using polarization analysis in the t-f-k domain

NASA Astrophysics Data System (ADS)

Wang, C.; Wang, Y.

2017-07-01

S waves travel slower than P waves and have a lower dominant frequency. Therefore, applying common techniques such as time-frequency filtering and f-k filtering to separate S waves from ground roll is difficult because ground roll is also characterized by slow velocity and low frequency. In this study, we present a method for attenuating ground roll using a polarization filtering method based on the t-f-k transform. We describe the particle motion of the waves by complex vector signals. Each pair of frequency components, whose frequencies have the same absolute value but different signs, of the complex signal indicate an elliptical or linear motion. The polarization parameters of the elliptical or linear motion are explicitly related to the two Fourier coefficients. We then extend these concepts to the t-f-k domain and propose a polarization filtering method for ground roll attenuation based on the t-f-k transform. The proposed approach can define automatically the time-varying reject zones on the f-k panel at different times as a function of the reciprocal ellipticity. Four attributes, time, frequency, apparent velocity and polarization are used to identify and extract the ground roll simultaneously. Thus, the ground roll and body waves can be separated as long as they are dissimilar in one of these attributes. We compare our method with commonly used filtering techniques by applying the methods to synthetic and real seismic data. The results indicate that our method can attenuate ground roll while preserving body waves more effectively than the other methods.

Adaptive attenuation of aliased ground roll using the shearlet transform

NASA Astrophysics Data System (ADS)

Hosseini, Seyed Abolfazl; Javaherian, Abdolrahim; Hassani, Hossien; Torabi, Siyavash; Sadri, Maryam

2015-01-01

Attenuation of ground roll is an essential step in seismic data processing. Spatial aliasing of the ground roll may cause the overlap of the ground roll with reflections in the f-k domain. The shearlet transform is a directional and multidimensional transform that separates the events with different dips and generates subimages in different scales and directions. In this study, the shearlet transform was used adaptively to attenuate aliased and non-aliased ground roll. After defining a filtering zone, an input shot record is divided into segments. Each segment overlaps adjacent segments. To apply the shearlet transform on each segment, the subimages containing aliased and non-aliased ground roll, the locations of these events on each subimage are selected adaptively. Based on these locations, mute is applied on the selected subimages. The filtered segments are merged together, using the Hanning function, after applying the inverse shearlet transform. This adaptive process of ground roll attenuation was tested on synthetic data, and field shot records from west of Iran. Analysis of the results using the f-k spectra revealed that the non-aliased and most of the aliased ground roll were attenuated using the proposed adaptive attenuation procedure. Also, we applied this method on shot records of a 2D land survey, and the data sets before and after ground roll attenuation were stacked and compared. The stacked section after ground roll attenuation contained less linear ground roll noise and more continuous reflections in comparison with the stacked section before the ground roll attenuation. The proposed method has some drawbacks such as more run time in comparison with traditional methods such as f-k filtering and reduced performance when the dip and frequency content of aliased ground roll are the same as those of the reflections.

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.

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

Utilization of the concentric circle model in clinical nursing: a review.

PubMed

Kazuma, K

1999-12-01

In this article, I review applications of the concentric circle model in clinical nursing. The concentric circle model is based on the cross-sectional shape of the body extremities at several points, and can be used in the areas of both kinesiology and nutritional science. This model makes it possible to calculate the cross-sectional area of muscles from measurement of the circumference of the extremities and the thickness of adipose (fatty) tissue. Then, changes in muscle strength or nutritional status can be inferred or assessed from these data. This model requires only simple and non-invasive measurements, and this is a significant and essential characteristic for its use by nurses, both in clinical and research applications.

The arteries of brain base in species of Bovini tribe.

PubMed

Zdun, Maciej; Frąckowiak, Hieronim; Kiełtyka-Kurc, Agata; Kowalczyk, Karolina; Nabzdyk, Maria; Timm, Anita

2013-11-01

Studies were conducted on 78 preparations of head and brain arteries in four species of Bos genus, that is in domestic cattle (N = 59), including 22 foetuses (CRL 36.5-78.5 cm), in banteng (Bos javanicus, N = 3), yak (Bos mutus f. grunniens, N = 2), American bison (Bison bison, N = 4), and European bison (Bison bonasus, N = 10). The comparative analysis permitted to demonstrate a similar pattern of brain base arteries in the studied animals. In the studied species, blood vessels of the arterial circle of the brain were found to form by bifurcation of intracranial segments of inner carotid arteries, which protruded from the paired rostral epidural rete mirabile. In Bovidae arterial circle of the brain was supplied with blood mainly by maxillary artery through the blood vessels of the paired rostral epidural rete mirabile. The unpaired caudal epidural rete mirabile was participating in blood supply to the arterial circle of the brain from vertebral and occipital arteries. It manifested character of a taxonomic trait for species of Bos and Bison genera. Basilar artery in all the examined animals manifested a variable diameter, with preliminary portion markedly narrowed, which prevented its participation in blood supply to the arterial circle of the brain. The results and taxonomic position of the species made the authors to suggest a hypothesis that a similar arterial pattern on the brain base might be present also in other species, not included in this analysis. Copyright © 2013 Wiley Periodicals, Inc.

Vibration analysis of paper machine's asymmetric tube roll supported by spherical roller bearings

NASA Astrophysics Data System (ADS)

Heikkinen, Janne E.; Ghalamchi, Behnam; Viitala, Raine; Sopanen, Jussi; Juhanko, Jari; Mikkola, Aki; Kuosmanen, Petri

2018-05-01

This paper presents a simulation method that is used to study subcritical vibrations of a tube roll in a paper machine. This study employs asymmetric 3D beam elements based on the Timoshenko beam theory. An asymmetric beam model accounts for varying stiffness and mass distributions. Additionally, a detailed rolling element bearing model defines the excitations arising from the set of spherical roller bearings at both ends of the rotor. The results obtained from the simulation model are compared against the results from the measurements. The results indicate that the waviness of the bearing rolling surfaces contributes significantly to the subcritical vibrations while the asymmetric properties of the tube roll have only a fractional effect on the studied vibrations.

Rapid Prototyping of Slot Die Devices for Roll to Roll Production of EL Fibers

PubMed Central

Bellingham, Alyssa; Bromhead, Nicholas; Fontecchio, Adam

2017-01-01

There is a growing interest in fibers supporting optoelectrical properties for textile and wearable display applications. Solution-processed electroluminescent (EL) material systems can be continuously deposited onto fiber or yarn substrates in a roll-to-roll process, making it easy to scale manufacturing. It is important to have precise control over layer deposition to achieve uniform and reliable light emission from these EL fibers. Slot-die coating offers this control and increases the rate of EL fiber production. Here, we report a highly adaptable, cost-effective 3D printing model for developing slot dies used in automatic coating systems. The resulting slot-die coating system enables rapid, reliable production of alternating current powder-based EL (ACPEL) fibers and can be adapted for many material systems. The benefits of this system over dip-coating for roll-to-roll production of EL fibers are demonstrated in this work. PMID:28772954

Rapid Prototyping of Slot Die Devices for Roll to Roll Production of EL Fibers.

PubMed

Bellingham, Alyssa; Bromhead, Nicholas; Fontecchio, Adam

2017-05-29

There is a growing interest in fibers supporting optoelectrical properties for textile and wearable display applications. Solution-processed electroluminescent (EL) material systems can be continuously deposited onto fiber or yarn substrates in a roll-to-roll process, making it easy to scale manufacturing. It is important to have precise control over layer deposition to achieve uniform and reliable light emission from these EL fibers. Slot-die coating offers this control and increases the rate of EL fiber production. Here, we report a highly adaptable, cost-effective 3D printing model for developing slot dies used in automatic coating systems. The resulting slot-die coating system enables rapid, reliable production of alternating current powder-based EL (ACPEL) fibers and can be adapted for many material systems. The benefits of this system over dip-coating for roll-to-roll production of EL fibers are demonstrated in this work.

Effect of roll compaction on granule size distribution of microcrystalline cellulose–mannitol mixtures: computational intelligence modeling and parametric analysis

PubMed Central

Kazemi, Pezhman; Khalid, Mohammad Hassan; Pérez Gago, Ana; Kleinebudde, Peter; Jachowicz, Renata; Szlęk, Jakub; Mendyk, Aleksander

2017-01-01

Dry granulation using roll compaction is a typical unit operation for producing solid dosage forms in the pharmaceutical industry. Dry granulation is commonly used if the powder mixture is sensitive to heat and moisture and has poor flow properties. The output of roll compaction is compacted ribbons that exhibit different properties based on the adjusted process parameters. These ribbons are then milled into granules and finally compressed into tablets. The properties of the ribbons directly affect the granule size distribution (GSD) and the quality of final products; thus, it is imperative to study the effect of roll compaction process parameters on GSD. The understanding of how the roll compactor process parameters and material properties interact with each other will allow accurate control of the process, leading to the implementation of quality by design practices. Computational intelligence (CI) methods have a great potential for being used within the scope of quality by design approach. The main objective of this study was to show how the computational intelligence techniques can be useful to predict the GSD by using different process conditions of roll compaction and material properties. Different techniques such as multiple linear regression, artificial neural networks, random forest, Cubist and k-nearest neighbors algorithm assisted by sevenfold cross-validation were used to present generalized models for the prediction of GSD based on roll compaction process setting and material properties. The normalized root-mean-squared error and the coefficient of determination (R2) were used for model assessment. The best fit was obtained by Cubist model (normalized root-mean-squared error =3.22%, R2=0.95). Based on the results, it was confirmed that the material properties (true density) followed by compaction force have the most significant effect on GSD. PMID:28176905

Effect of roll compaction on granule size distribution of microcrystalline cellulose-mannitol mixtures: computational intelligence modeling and parametric analysis.

PubMed

Kazemi, Pezhman; Khalid, Mohammad Hassan; Pérez Gago, Ana; Kleinebudde, Peter; Jachowicz, Renata; Szlęk, Jakub; Mendyk, Aleksander

2017-01-01

Dry granulation using roll compaction is a typical unit operation for producing solid dosage forms in the pharmaceutical industry. Dry granulation is commonly used if the powder mixture is sensitive to heat and moisture and has poor flow properties. The output of roll compaction is compacted ribbons that exhibit different properties based on the adjusted process parameters. These ribbons are then milled into granules and finally compressed into tablets. The properties of the ribbons directly affect the granule size distribution (GSD) and the quality of final products; thus, it is imperative to study the effect of roll compaction process parameters on GSD. The understanding of how the roll compactor process parameters and material properties interact with each other will allow accurate control of the process, leading to the implementation of quality by design practices. Computational intelligence (CI) methods have a great potential for being used within the scope of quality by design approach. The main objective of this study was to show how the computational intelligence techniques can be useful to predict the GSD by using different process conditions of roll compaction and material properties. Different techniques such as multiple linear regression, artificial neural networks, random forest, Cubist and k-nearest neighbors algorithm assisted by sevenfold cross-validation were used to present generalized models for the prediction of GSD based on roll compaction process setting and material properties. The normalized root-mean-squared error and the coefficient of determination ( R 2 ) were used for model assessment. The best fit was obtained by Cubist model (normalized root-mean-squared error =3.22%, R 2 =0.95). Based on the results, it was confirmed that the material properties (true density) followed by compaction force have the most significant effect on GSD.

Reactivation of Chromosomally Integrated Human Herpesvirus-6 by Telomeric Circle Formation

PubMed Central

Prusty, Bhupesh K.; Krohne, George; Rudel, Thomas

2013-01-01

More than 95% of the human population is infected with human herpesvirus-6 (HHV-6) during early childhood and maintains latent HHV-6 genomes either in an extra-chromosomal form or as a chromosomally integrated HHV-6 (ciHHV-6). In addition, approximately 1% of humans are born with an inheritable form of ciHHV-6 integrated into the telomeres of chromosomes. Immunosuppression and stress conditions can reactivate latent HHV-6 replication, which is associated with clinical complications and even death. We have previously shown that Chlamydia trachomatis infection reactivates ciHHV-6 and induces the formation of extra-chromosomal viral DNA in ciHHV-6 cells. Here, we propose a model and provide experimental evidence for the mechanism of ciHHV-6 reactivation. Infection with Chlamydia induced a transient shortening of telomeric ends, which subsequently led to increased telomeric circle (t-circle) formation and incomplete reconstitution of circular viral genomes containing single viral direct repeat (DR). Correspondingly, short t-circles containing parts of the HHV-6 DR were detected in cells from individuals with genetically inherited ciHHV-6. Furthermore, telomere shortening induced in the absence of Chlamydia infection also caused circularization of ciHHV-6, supporting a t-circle based mechanism for ciHHV-6 reactivation. PMID:24367281

Regional Interrelationships: A Leadership Opportunity for Health Care.

PubMed

Rotarius, Timothy; Liberman, Aaron

Given the impact that the health care industry has on the national economy, health care executives need to move beyond simply providing health care treatments and instead focus on strategically leading their regions, including the other key industry contributors in their specific regions. Geographic and economic regions can be viewed as concentric circles of influence, with each circle recognizing the resources and contributions that are specific to a region. An acknowledgement by health care executives of the regional interrelationships that exist in a specific region is necessary for health care managers to strategically lead regional interrelationships. A template for implementation of this process is included. To understand the various factors that exist within circles of influence, several distinct yet interrelated vertical bases of knowledge will be discussed. The 5 bases of knowledge examined here include the following: Health Care, Tourism, Defense and Technology, Education, and Retail. It is important to note that the resources identified in the Tourism, Defense and Technology, Education, and Retail knowledge bases all have a direct influential relationship upon the health care resources of the region. For description purposes, the Central Florida geographic and economic region will be examined for interrelationships between the 5 knowledge bases.

Rolling Process Modeling Report. Finite-Element Model Validation and Parametric Study on various Rolling Process parameters

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

Soulami, Ayoub; Lavender, Curt A.; Paxton, Dean M.

2015-06-15

Pacific Northwest National Laboratory (PNNL) has been investigating manufacturing processes for the uranium-10% molybdenum alloy plate-type fuel for high-performance research reactors in the United States. This work supports the U.S. Department of Energy National Nuclear Security Administration’s Office of Material Management and Minimization Reactor Conversion Program. This report documents modeling results of PNNL’s efforts to perform finite-element simulations to predict roll-separating forces for various rolling mill geometries for PNNL, Babcock & Wilcox Co., Y-12 National Security Complex, Los Alamos National Laboratory, and Idaho National Laboratory. The model developed and presented in a previous report has been subjected to further validationmore » study using new sets of experimental data generated from a rolling mill at PNNL. Simulation results of both hot rolling and cold rolling of uranium-10% molybdenum coupons have been compared with experimental results. The model was used to predict roll-separating forces at different temperatures and reductions for five rolling mills within the National Nuclear Security Administration Fuel Fabrication Capability project. This report also presents initial results of a finite-element model microstructure-based approach to study the surface roughness at the interface between zirconium and uranium-10% molybdenum.« less

75 FR 3459 - Combined Notice of Filings # 1

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-21

.... Docket Numbers: ER10-276-001. Applicants: Rolling Thunder I Power Partners, LLC. Description: Rolling Thunder I Power Partners, LLC supplements its 11/17/09 application for a proposed market-based rate...

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.

Quantitative Residual Strain Analyses on Strain Hardened Nickel Based Alloy

NASA Astrophysics Data System (ADS)

Yonezawa, Toshio; Maeguchi, Takaharu; Goto, Toru; Juan, Hou

Many papers have reported about the effects of strain hardening by cold rolling, grinding, welding, etc. on stress corrosion cracking susceptibility of nickel based alloys and austenitic stainless steels for LWR pipings and components. But, the residual strain value due to cold rolling, grinding, welding, etc. is not so quantitatively evaluated.

Rock and Roll English Teaching: Content-Based Cultural Workshops

ERIC Educational Resources Information Center

Robinson, Tim

2011-01-01

In this article, the author shares a content-based English as a Second/Foreign Language (ESL/EFL) workshop that strengthens language acquisition, increases intrinsic motivation, and bridges cultural divides. He uses a rock and roll workshop to introduce an organizational approach with a primary emphasis on cultural awareness content and a…

Judging rolling wheels: Dynamic and kinematic aspects of rotation-translation coupling

NASA Technical Reports Server (NTRS)

Hecht, Heiko

1993-01-01

Four experiments were carried out to investigate observers' abilities to judge rolling motions. The experiments were designed to assess whether two important aspects of such motions are appreciated: the kinematic coupling of rotation and translation, and the dynamic effects of gravity. Different motion contexts of rolling wheels were created using computer-generated displays. The first experiment involved wheels rolling down an inclined plane. Observers spontaneously appreciated the anomaly of wheels that failed to accelerate, but they were not able to differentiate between different acceleration functions. Moreover, their judgements were almost exclusively based on the translation component of the rolling motion, neglecting the rotation component. In a second experiment it was found that observers could accurately estimate the perimeter of various objects. Thus, their inability to consider rotation information is not attributable to misperceptions of the geometry of wheels. In a third experiment the finding that rolling wheels appear to overrotate was replicated; however, findings from this experiment also showed, together with those from a fourth experiment, that observers are able to make very accurate judgments about translation-rotation coupling in rolling wheels when information is provided about the orientation of the wheel and the texture of the surface on which it rolls.

Judging rolling wheels: dynamic and kinematic aspects of rotation-translation coupling.

PubMed

Hecht, H

1993-01-01

Four experiments were carried out to investigate observers' abilities to judge rolling motions. The experiments were designed to assess whether two important aspects of such motions are appreciated: the kinematic coupling of rotation and translation, and the dynamic effects of gravity. Different motion contexts of rolling wheels were created using computer-generated displays. The first experiment involved wheels rolling down an inclined plane. Observers spontaneously appreciated the anomaly of wheels that failed to accelerate, but they were not able to differentiate between different acceleration functions. Moreover, their judgments were almost exclusively based on the translation component of the rolling motion, neglecting the rotation component. In a second experiment it was found that observers could accurately estimate the perimeter of various objects. Thus, their inability to consider rotation information is not attributable to misperceptions of the geometry of wheels. In a third experiment the finding that rolling wheels appear to overrotate was replicated; however, findings from this experiment also showed, together with those from a fourth experiment, that observers are able to make very accurate judgments about translation-rotation coupling in rolling wheels when information is provided about the orientation of the wheel and the texture of the surface on which it rolls.

Analytical study on web deformation by tension in roll-to-roll printing process

NASA Astrophysics Data System (ADS)

Kang, Y. S.; Hong, M. S.; Lee, S. H.; Jeon, Y. H.; Kang, D.; Lee, N. K.; Lee, M. G.

2017-08-01

Recently, flexible devices have gained high intentions for flexible display, Radio Frequency Identification (RFID), bio-sensor and so on. For manufacturing of the flexible devices, roll-to-roll process is a good candidate because of its low production cost and high productivity. Flexible substrate has a non-uniform deformation distribution by tension. Because the roll-to-roll process carries out a number of overlay printing processes, the deformation affect overlay printing precision and printable areas. In this study, the deformation of flexible substrate was analyzed by using finite element analysis and it was verified through experiments. More deformation occurred in the middle region in the direction parallel to rolling of the flexible substrate. It is confirmed through experiments and analysis that deformation occurs less at the both ends than in the middle region. Based on these results, a hourglass roll is proposed as a mechanical design of the roll to compensate the non-uniform deformation of the flexible substrate. In the hourglass roll, high stiffness material is used in the core and low stiffness material such as an elastic material is wrapped. The diameter of the core roll was designed to be the minimum at the middle and the maximum at both ends. We tried to compensate the non-uniform deformation distribution of the flexible substrate by using the variation of the contact stiffness between the roll and the flexible substrate. Deformation distribution of flexible substrates was confirmed by finite element analysis by applying hourglass roll shape. In the analysis when using the hourglass roll, it is confirmed that the stress distribution is compensated by about 70% and the strain distribution is compensated by about 67% compared to the case using the hourglass roll. To verify the compensation of the non-uniform deformation distribution due to the tension, deformation measurement experiment when using the proposed hourglass roll was carried out. Experiments have shown that the distribution of deformation is compensated by about 34%. From the results, we verified the performance of the proposed.

Numerical and experimental investigation of strip deformation in cage roll forming process for pipes with low ratio of thickness/diameter

NASA Astrophysics Data System (ADS)

Kasaei, M. M.; Naeini, H. Moslemi; Tehrani, M. Salmani; Tafti, R. Azizi

2011-01-01

Cage roll forming is one of the advanced methods of cold roll forming process which is used widely for producing ERW pipes. In addition to decreasing the production cost and time, using cage roll forming provides smooth deformation on the strip. Few studies can be found about cage roll forming because of its complexity, and the available knowledge is experience-based more than science-based. In this paper, deformation of pipes with low ratio of thickness/diameter is investigated by 3D finite element simulation in Marc-Mentat software. Edge buckling defect in cage roll forming of low ratio of thickness/diameter pipes is very important. Due to direct influence of longitudinal strain on the edge buckling phenomenon, longitudinal strains at the edge and center line of the strip are investigated and high risk stands are introduced. The deformed strip is predicted using the simulation results and effects of each cage forming stage on the deformed strip profile are specified. In order to verify the simulation results, strip width and opening distance of the two edges in different forming stages are obtained from the simulations and compared with the experimental data which were measured from the production line. A good agreement between the experimental and simulated results is observed.

Roll-Yaw control at high angle of attack by forebody tangential blowing

NASA Technical Reports Server (NTRS)

Pedreiro, N.; Rock, S. M.; Celik, Z. Z.; Roberts, L.

1995-01-01

The feasibility of using forebody tangential blowing to control the roll-yaw motion of a wind tunnel model is experimentally demonstrated. An unsteady model of the aerodynamics is developed based on the fundamental physics of the flow. Data from dynamic experiments is used to validate the aerodynamic model. A unique apparatus is designed and built that allows the wind tunnel model two degrees of freedom, roll and yaw. Dynamic experiments conducted at 45 degrees angle of attack reveal the system to be unstable. The natural motion is divergent. The aerodynamic model is incorporated into the equations of motion of the system and used for the design of closed loop control laws that make the system stable. These laws are proven through dynamic experiments in the wind tunnel using blowing as the only actuator. It is shown that asymmetric blowing is a highly non-linear effector that can be linearized by superimposing symmetric blowing. The effects of forebody tangential blowing and roll and yaw angles on the flow structure are determined through flow visualization experiments. The transient response of roll and yaw moments to a step input blowing are determined. Differences on the roll and yaw moment dependence on blowing are explained based on the physics of the phenomena.

Roll-yaw control at high angle of attack by forebody tangential blowing

NASA Technical Reports Server (NTRS)

Pedreiro, N.; Rock, S. M.; Celik, Z. Z.; Roberts, L.

1995-01-01

The feasibility of using forebody tangential blowing to control the roll-yaw motion of a wind tunnel model is experimentally demonstrated. An unsteady model of the aerodynamics is developed based on the fundamental physics of the flow. Data from dynamic experiments is used to validate the aerodynamic model. A unique apparatus is designed and built that allows the wind tunnel model two degrees of freedom, roll and yaw. Dynamic experiments conducted at 45 degrees angle of attack reveal the system to be unstable. The natural motion is divergent. The aerodynamic model is incorporated into the equations of motion of the system and used for the design of closed loop control laws that make the system stable. These laws are proven through dynamic experiments in the wind tunnel using blowing as the only actuator. It is shown that asymmetric blowing is a highly non-linear effector that can be linearized by superimposing symmetric blowing. The effects of forebody tangential blowing and roll and yaw angles on the flow structure are determined through flow visualization experiments. The transient response of roll and yaw moments to a step input blowing are determined. Differences on the roll and yaw moment dependence on blowing are explained based on the physics of the phenomena.

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.

A Monocular Vision Measurement System of Three-Degree-of-Freedom Air-Bearing Test-Bed Based on FCCSP

NASA Astrophysics Data System (ADS)

Gao, Zhanyu; Gu, Yingying; Lv, Yaoyu; Xu, Zhenbang; Wu, Qingwen

2018-06-01

A monocular vision-based pose measurement system is provided for real-time measurement of a three-degree-of-freedom (3-DOF) air-bearing test-bed. Firstly, a circular plane cooperative target is designed. An image of a target fixed on the test-bed is then acquired. Blob analysis-based image processing is used to detect the object circles on the target. A fast algorithm (FCCSP) based on pixel statistics is proposed to extract the centers of object circles. Finally, pose measurements can be obtained when combined with the centers and the coordinate transformation relation. Experiments show that the proposed method is fast, accurate, and robust enough to satisfy the requirement of the pose measurement.

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…

Effect of deformation path on microstructure, microhardness and texture evolution of interstitial free steel fabricated by differential speed rolling

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

Hamad, Kotiba; Chung, Bong Kwon; Ko, Young Gun, E-mail: younggun@ynu.ac.kr

2014-08-15

This paper reports the effect of the deformation path on the microstructure, microhardness, and texture evolution of interstitial free (IF) steel processed by differential speed rolling (DSR) method. For this purpose, total height reductions of 50% and 75% were imposed on the samples by a series of differential speed rolling operations with various height reductions per pass (deformation levels) ranging from 10 to 50% under a fixed roll speed ratio of 1:4 for the upper and lower rolls, respectively. Microstructural observations using transmission electron microscopy and electron backscattered diffraction measurements showed that the samples rolled at deformation level of 50%more » had the finest mean grain size (∼ 0.5 μm) compared to the other counterparts; also the samples rolled at deformation level of 50% showed a more uniform microstructure. Based on the microhardness measurements along the thickness direction of the deformed samples, gradual evolution of the microhardness value and its homogeneity was observed with the increase of the deformation level per pass. Texture analysis showed that, as the deformation level per pass increased, the fraction of alpha fiber and gamma fiber in the deformed samples increased. The textures obtained by the differential speed rolling process under the lubricated condition would be equivalent to those obtained by the conventional rolling. - Highlights: • Effect of DSR deformation path on microstructure of IF steel is significant. • IF steel rolled at deformation level of 50% has the ultrafine grains of ∼ 0.5 μm. • Rolling texture components are pronounced with increasing deformation level.« less

Aluminum-based one- and two-dimensional micro fin array structures: high-throughput fabrication and heat transfer testing

NASA Astrophysics Data System (ADS)

Primeaux, Philip A.; Zhang, Bin; Zhang, Xiaoman; Miller, Jacob; Meng, W. J.; KC, Pratik; Moore, Arden L.

2017-02-01

Microscale fin array structures were replicated onto surfaces of aluminum 1100 and aluminum 6061 alloy (Al1100/Al6061) sheet metals through room-temperature instrumented roll molding. Aluminum-based micro fin arrays were replicated at room temperature, and the fabrication process is one with high throughput and low cost. One-dimensional (1D) micro fin arrays were made through one-pass rolling, while two-dimensional (2D) micro fin arrays were made by sequential 90° cross rolling with the same roller sleeve. For roll molding of 1D micro fins, fin heights greater than 600 µm were achieved and were shown to be proportional to the normal load force per feature width. At a given normal load force, the fin height was further shown to scale inversely with the hardness of the sheet metal. For sequential 90° cross rolling, morphologies of roll molded 2D micro fin arrays were examined, which provided clues to understand how plastic deformation occurred under cross rolling conditions. A series of pool boiling experiments on low profile Al micro fin array structures were performed within Novec 7100, a widely used commercial dielectric coolant. Results for both horizontal and vertical surface orientations show that roll molded Al micro fin arrays can increase heat flux at fixed surface temperature as compared to un-patterned Al sheet. The present results further suggest that many factors beyond just increased surface area can influence heat transfer performance, including surface finish and the important multiphase transport mechanisms in and around the fin geometry. These factors must also be considered when designing and optimizing micro fin array structures for heat transfer applications.

Investigation of interactions between limb-manipulator dynamics and effective vehicle roll control characteristics

NASA Technical Reports Server (NTRS)

Johnston, D. E.; Mcruer, D. T.

1986-01-01

A fixed-base simulation was performed to identify and quantify interactions between the pilot's hand/arm neuromuscular subsystem and such features of typical modern fighter aircraft roll rate command control system mechanization as: (1) force sensing side-stick type manipulator; (2) vehicle effective role time constant; and (3) flight control system effective time delay. The simulation results provide insight to high frequency pilot induced oscillations (PIO) (roll ratchet), low frequency PIO, and roll-to-right control and handling problems previously observed in experimental and production fly-by-wire control systems. The simulation configurations encompass and/or duplicate actual flight situations, reproduce control problems observed in flight, and validate the concept that the high frequency nuisance mode known as roll ratchet derives primarily from the pilot's neuromuscular subsystem. The simulations show that force-sensing side-stick manipulator force/displacement/command gradients, command prefilters, and flight control system time delays need to be carefully adjusted to minimize neuromuscular mode amplitude peaking (roll ratchet tendency) without restricting roll control bandwidth (with resulting sluggish or PIO prone control).

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.

Harnessing user generated multimedia content in the creation of collaborative classification structures and retrieval learning games

NASA Astrophysics Data System (ADS)

Borchert, Otto Jerome

This paper describes a software tool to assist groups of people in the classification and identification of real world objects called the Classification, Identification, and Retrieval-based Collaborative Learning Environment (CIRCLE). A thorough literature review identified current pedagogical theories that were synthesized into a series of five tasks: gathering, elaboration, classification, identification, and reinforcement through game play. This approach is detailed as part of an included peer reviewed paper. Motivation is increased through the use of formative and summative gamification; getting points completing important portions of the tasks and playing retrieval learning based games, respectively, which is also included as a peer-reviewed conference proceedings paper. Collaboration is integrated into the experience through specific tasks and communication mediums. Implementation focused on a REST-based client-server architecture. The client is a series of web-based interfaces to complete each of the tasks, support formal classroom interaction through faculty accounts and student tracking, and a module for peers to help each other. The server, developed using an in-house JavaMOO platform, stores relevant project data and serves data through a series of messages implemented as a JavaScript Object Notation Application Programming Interface (JSON API). Through a series of two beta tests and two experiments, it was discovered the second, elaboration, task requires considerable support. While students were able to properly suggest experiments and make observations, the subtask involving cleaning the data for use in CIRCLE required extra support. When supplied with more structured data, students were enthusiastic about the classification and identification tasks, showing marked improvement in usability scores and in open ended survey responses. CIRCLE tracks a variety of educationally relevant variables, facilitating support for instructors and researchers. Future work will revolve around material development, software refinement, and theory building. Curricula, lesson plans, instructional materials need to be created to seamlessly integrate CIRCLE in a variety of courses. Further refinement of the software will focus on improving the elaboration interface and developing further game templates to add to the motivation and retrieval learning aspects of the software. Data gathered from CIRCLE experiments can be used to develop and strengthen theories on teaching and learning.

Overlay accuracy on a flexible web with a roll printing process based on a roll-to-roll system.

PubMed

Chang, Jaehyuk; Lee, Sunggun; Lee, Ki Beom; Lee, Seungjun; Cho, Young Tae; Seo, Jungwoo; Lee, Sukwon; Jo, Gugrae; Lee, Ki-yong; Kong, Hyang-Shik; Kwon, Sin

2015-05-01

For high-quality flexible devices from printing processes based on Roll-to-Roll (R2R) systems, overlay alignment during the patterning of each functional layer poses a major challenge. The reason is because flexible substrates have a relatively low stiffness compared with rigid substrates, and they are easily deformed during web handling in the R2R system. To achieve a high overlay accuracy for a flexible substrate, it is important not only to develop web handling modules (such as web guiding, tension control, winding, and unwinding) and a precise printing tool but also to control the synchronization of each unit in the total system. A R2R web handling system and reverse offset printing process were developed in this work, and an overlay between the 1st and 2nd layers of ±5μm on a 500 mm-wide film was achieved at a σ level of 2.4 and 2.8 (x and y directions, respectively) in a continuous R2R printing process. This paper presents the components and mechanisms used in reverse offset printing based on a R2R system and the printing results including positioning accuracy and overlay alignment accuracy.

A Hybrid Generalized Hidden Markov Model-Based Condition Monitoring Approach for Rolling Bearings

PubMed Central

Liu, Jie; Hu, Youmin; Wu, Bo; Wang, Yan; Xie, Fengyun

2017-01-01

The operating condition of rolling bearings affects productivity and quality in the rotating machine process. Developing an effective rolling bearing condition monitoring approach is critical to accurately identify the operating condition. In this paper, a hybrid generalized hidden Markov model-based condition monitoring approach for rolling bearings is proposed, where interval valued features are used to efficiently recognize and classify machine states in the machine process. In the proposed method, vibration signals are decomposed into multiple modes with variational mode decomposition (VMD). Parameters of the VMD, in the form of generalized intervals, provide a concise representation for aleatory and epistemic uncertainty and improve the robustness of identification. The multi-scale permutation entropy method is applied to extract state features from the decomposed signals in different operating conditions. Traditional principal component analysis is adopted to reduce feature size and computational cost. With the extracted features’ information, the generalized hidden Markov model, based on generalized interval probability, is used to recognize and classify the fault types and fault severity levels. Finally, the experiment results show that the proposed method is effective at recognizing and classifying the fault types and fault severity levels of rolling bearings. This monitoring method is also efficient enough to quantify the two uncertainty components. PMID:28524088

A fosmid cloning strategy for detecting the widest possible spectrum of microbes from the international space station drinking water system.

PubMed

Choi, Sangdun; Chang, Mi Sook; Stuecker, Tara; Chung, Christine; Newcombe, David A; Venkateswaran, Kasthuri

2012-12-01

In this study, fosmid cloning strategies were used to assess the microbial populations in water from the International Space Station (ISS) drinking water system (henceforth referred to as Prebiocide and Tank A water samples). The goals of this study were: to compare the sensitivity of the fosmid cloning strategy with that of traditional culture-based and 16S rRNA-based approaches and to detect the widest possible spectrum of microbial populations during the water purification process. Initially, microbes could not be cultivated, and conventional PCR failed to amplify 16S rDNA fragments from these low biomass samples. Therefore, randomly primed rolling-circle amplification was used to amplify any DNA that might be present in the samples, followed by size selection by using pulsed-field gel electrophoresis. The amplified high-molecular-weight DNA from both samples was cloned into fosmid vectors. Several hundred clones were randomly selected for sequencing, followed by Blastn/Blastx searches. Sequences encoding specific genes from Burkholderia, a species abundant in the soil and groundwater, were found in both samples. Bradyrhizobium and Mesorhizobium, which belong to rhizobia, a large community of nitrogen fixers often found in association with plant roots, were present in the Prebiocide samples. Ralstonia, which is prevalent in soils with a high heavy metal content, was detected in the Tank A samples. The detection of many unidentified sequences suggests the presence of potentially novel microbial fingerprints. The bacterial diversity detected in this pilot study using a fosmid vector approach was higher than that detected by conventional 16S rRNA gene sequencing.

Tropical Cyclone Boundary Layer Rolls in Synthetic Aperture Radar Imagery

NASA Astrophysics Data System (ADS)

Huang, Lanqing; Li, Xiaofeng; Liu, Bin; Zhang, Jun A.; Shen, Dongliang; Zhang, Zenghui; Yu, Wenxian

2018-04-01

Marine atmospheric boundary layer (MABL) roll plays an important role in the turbulent exchange of momentum, sensible heat, and moisture throughout MABL of tropical cyclone (TC). Hence, rolls are believed to be closely related to TC's development, intensification, and decay processes. Spaceborne synthetic aperture radar (SAR) provides a unique capability to image the sea surface imprints of quasi-linear streaks induced by the MABL rolls within a TC. In this study, sixteen SAR images, including three images acquired during three major hurricanes: Irma, Jose, and Maria in the 2017 Atlantic hurricane season, were utilized to systematically map the distribution and wavelength of MABL rolls under the wide range of TC intensities. The images were acquired by SAR onboard RADARSAT-1/2, ENVISAT, and SENTINEL-1 satellites. Our findings are in agreement with the previous one case study of Hurricane Katrina (2005), showing the roll wavelengths are between 600 and 1,600 m. We also find that there exist roll imprints in eyewall and rainbands, although the boundary layer heights are shallower there. Besides, the spatial distribution of roll wavelengths is asymmetrical. The roll wavelengths are found to be the shortest around the storm center, increase and then decrease with distance from storm center, reaching the peak values in the range of d∗-2d∗, where d∗ is defined as the physical location to TC centers normalized by the radius of maximum wind. These MABL roll characteristics cannot be derived using conventional aircraft and land-based Doppler radar observations.

Effects of alignment on the roll-over shapes of prosthetic feet.

PubMed

Hansen, Andrew

2008-12-01

Recent work suggests that a prosthetic ankle-foot component's roll-over shape - the effective rocker it conforms to between initial contact and opposite initial contact (the 'roll-over' interval of walking) - is closely linked to its final alignment in the prosthesis (as determined by a skilled prosthetist using heuristic techniques). If true, this information may help to determine the appropriate alignment for a lower limb prosthesis before it is built, or a priori. Knowledge is needed for future models that will incorporate the roll-over shape including the relative effect of alignment on the roll-over shape's radius of curvature and arc length. The purpose of this study was to evaluate the hypotheses that: (i) Changes in prosthesis alignment alter the position and orientation of a foot's roll-over shape in prosthesis-based coordinates, and (ii) these changes occur without changing the radius of curvature or arc length of the roll-over shape. To examine the hypotheses, this study examined the effects of nine alignment settings on the roll-over shapes of two prosthetic feet. The idea that alignment changes move and rotate roll-over shapes of prosthetic feet in prosthesis coordinates is supported by this work, but the hypothesis that the radius of curvature and arc length do not change for different alignments is not strongly supported by the data. A revised approach is presented that explains some of the changes to the roll-over shape parameters due to changes in rotational alignment.

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…

Distortion theorems for polynomials on a circle

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

Dubinin, V N

2000-12-31

Inequalities for the derivatives with respect to {phi}=arg z the functions ReP(z), |P(z)|{sup 2} and arg P(z) are established for an algebraic polynomial P(z) at points on the circle |z|=1. These estimates depend, in particular, on the constant term and the leading coefficient of the polynomial P(z) and improve the classical Bernstein and Turan inequalities. The method of proof is based on the techniques of generalized reduced moduli.

Rolling scheduling of electric power system with wind power based on improved NNIA algorithm

NASA Astrophysics Data System (ADS)

Xu, Q. S.; Luo, C. J.; Yang, D. J.; Fan, Y. H.; Sang, Z. X.; Lei, H.

2017-11-01

This paper puts forth a rolling modification strategy for day-ahead scheduling of electric power system with wind power, which takes the operation cost increment of unit and curtailed wind power of power grid as double modification functions. Additionally, an improved Nondominated Neighbor Immune Algorithm (NNIA) is proposed for solution. The proposed rolling scheduling model has further improved the operation cost of system in the intra-day generation process, enhanced the system’s accommodation capacity of wind power, and modified the key transmission section power flow in a rolling manner to satisfy the security constraint of power grid. The improved NNIA algorithm has defined an antibody preference relation model based on equal incremental rate, regulation deviation constraints and maximum & minimum technical outputs of units. The model can noticeably guide the direction of antibody evolution, and significantly speed up the process of algorithm convergence to final solution, and enhance the local search capability.

Automatic Clustering of Rolling Element Bearings Defects with Artificial Neural Network

NASA Astrophysics Data System (ADS)

Antonini, M.; Faglia, R.; Pedersoli, M.; Tiboni, M.

2006-06-01

The paper presents the optimization of a methodology for automatic clustering based on Artificial Neural Networks to detect the presence of defects in rolling bearings. The research activity was developed in co-operation with an Italian company which is expert in the production of water pumps for automotive use (Industrie Saleri Italo). The final goal of the work is to develop a system for the automatic control of the pumps, at the end of the production line. In this viewpoint, we are gradually considering the main elements of the water pump, which can cause malfunctioning. The first elements we have considered are the rolling bearing, a very critic component for the system. The experimental activity is based on the vibration measuring of rolling bearings opportunely damaged; vibration signals are in the second phase elaborated; the third and last phase is an automatic clustering. Different signal elaboration techniques are compared to optimize the methodology.

An investigation of the effects of pitch-roll (de)-coupling on helicopter handling qualities

NASA Technical Reports Server (NTRS)

Ockier, C. J.; Pausder, H. J.; Blanken, C. L.

1995-01-01

An investigation of the effects of pitch-roll coupling on helicopter handling qualities was performed by the US Army and DLR, using a NASA ground-based and a DLR inflight simulator. Over 90 different coupling configurations were evaluated using a roll-axis tracking task. The results show that although the current ADS-33C coupling criterion discriminates against those types of coupling typical of conventionally controlled helicopters, it not always suited for the prediction of handling qualities of helicopters with modern control systems. Based on the observation that high frequency inputs during tracking are used to alleviate coupling, a frequency domain pitch-roll coupling criterion that uses the average coupling ratio between the bandwidth and neutral stability frequency is formulated. This criterion provides a more comprehensive coverage with respect to the different types of coupling and shows excellent consistency.

Investigating the role of sliding friction in rolling motion: a teaching sequence based on experiments and simulations

NASA Astrophysics Data System (ADS)

De Ambrosis, Anna; Malgieri, Massimiliano; Mascheretti, Paolo; Onorato, Pasquale

2015-05-01

We designed a teaching-learning sequence on rolling motion, rooted in previous research about student conceptions, and proposing an educational reconstruction strongly centred on the role of friction in different cases of rolling. A series of experiments based on video analysis is used to highlight selected key concepts and to motivate students in their exploration of the topic; and interactive simulations, which can be modified on the fly by students to model different physical situations, are used to stimulate autonomous investigation in enquiry activities. The activity sequence was designed for students on introductory physics courses and was tested with a group of student teachers. Comparisons between pre- and post-tests, and between our results and those reported in the literature, indicate that students’ understanding of rolling motion improved markedly and some typical difficulties were overcome.

Fault Diagnosis of Rolling Bearing Based on Fast Nonlocal Means and Envelop Spectrum

PubMed Central

Lv, Yong; Zhu, Qinglin; Yuan, Rui

2015-01-01

The nonlocal means (NL-Means) method that has been widely used in the field of image processing in recent years effectively overcomes the limitations of the neighborhood filter and eliminates the artifact and edge problems caused by the traditional image denoising methods. Although NL-Means is very popular in the field of 2D image signal processing, it has not received enough attention in the field of 1D signal processing. This paper proposes a novel approach that diagnoses the fault of a rolling bearing based on fast NL-Means and the envelop spectrum. The parameters of the rolling bearing signals are optimized in the proposed method, which is the key contribution of this paper. This approach is applied to the fault diagnosis of rolling bearing, and the results have shown the efficiency at detecting roller bearing failures. PMID:25585105

Application of improved wavelet total variation denoising for rolling bearing incipient fault diagnosis

NASA Astrophysics Data System (ADS)

Zhang, W.; Jia, M. P.

2018-06-01

When incipient fault appear in the rolling bearing, the fault feature is too small and easily submerged in the strong background noise. In this paper, wavelet total variation denoising based on kurtosis (Kurt-WATV) is studied, which can extract the incipient fault feature of the rolling bearing more effectively. The proposed algorithm contains main steps: a) establish a sparse diagnosis model, b) represent periodic impulses based on the redundant wavelet dictionary, c) solve the joint optimization problem by alternating direction method of multipliers (ADMM), d) obtain the reconstructed signal using kurtosis value as criterion and then select optimal wavelet subbands. This paper uses overcomplete rational-dilation wavelet transform (ORDWT) as a dictionary, and adjusts the control parameters to achieve the concentration in the time-frequency plane. Incipient fault of rolling bearing is used as an example, and the result shows that the effectiveness and superiority of the proposed Kurt- WATV bearing fault diagnosis algorithm.

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 ...

Effect of roll-compaction and milling conditions on granules and tablet properties.

PubMed

Perez-Gandarillas, Lucia; Perez-Gago, Ana; Mazor, Alon; Kleinebudde, Peter; Lecoq, Olivier; Michrafy, Abderrahim

2016-09-01

Dry granulation is an agglomeration process used to produce size-enlarged particles (granules), improving the handling properties of powders such as flowability. In this process, powders are compacted using a roll press to produce ribbons, which are milled in granules used further in the tableting process. The granule and tablet properties are influenced by the existence of different designs of the roll compactors, milling systems and the interaction between process parameters and raw material properties. The main objective of this work was to investigate how different roll-compaction conditions and milling process parameters impact on ribbons, granules and tablet properties, highlighting the role of the sealing system (cheek plates and rimmed roll). In this context, two common excipients differing in their mechanical behaviour (MCC and mannitol) are used. The study is based on the analysis of granule size distribution together with the characterization of loss of compactability during die compaction. Results show that the tensile strength of tablets is lower when using granules than when the raw materials are compressed. Moreover, the plastic material (MCC) is more sensitive than the brittle one (mannitol). Regarding the roll-force, it is observed that the higher the roll force, the lower the tensile strength of tablets from granulated material is. These findings are in agreement with the literature. The comparison of sealing systems shows that the rimmed-roll system leads to slightly stronger tablets than the use of cheek plates. In addition, the use of the rimmed-roll system reduces the amount of fines, in particular when high roll force is applied. Overall, it can be concluded that roll-compaction effect is predominant over the milling effect on the production of fines but less significant on the tablet properties. This study points out that the balance between a good flowability by reducing the amount of fines and appropriate tablet strength is achieved with rimmed-roll and the highest roll-force used. Copyright © 2016 Elsevier B.V. All rights reserved.

Experimental investigation on the electrical contact behavior of rolling contact connector.

PubMed

Chen, Junxing; Yang, Fei; Luo, Kaiyu; Zhu, Mingliang; Wu, Yi; Rong, Mingzhe

2015-12-01

Rolling contact connector (RCC) is a new technology utilized in high performance electric power transfer systems with one or more rotating interfaces, such as radars, satellites, wind generators, and medical computed tomography machines. Rolling contact components are used in the RCC instead of traditional sliding contacts to transfer electrical power and/or signal. Since the requirement of the power transmission is increasing in these years, the rolling electrical contact characteristics become more and more important for the long-life design of RCC. In this paper, a typical form of RCC is presented. A series of experimental work are carried out to investigate the rolling electrical contact characteristics during its lifetime. The influence of a variety of factors on the electrical contact degradation behavior of RCC is analyzed under both vacuum and air environment. Based on the surface morphology and elemental composition changes in the contact zone, which are assessed by field emission scanning electron microscope and confocal laser scanning microscope, the mechanism of rolling electrical contact degradation is discussed.

Numerical simulation study on rolling-chemical milling process of aluminum-lithium alloy skin panel

NASA Astrophysics Data System (ADS)

Huang, Z. B.; Sun, Z. G.; Sun, X. F.; Li, X. Q.

2017-09-01

Single curvature parts such as aircraft fuselage skin panels are usually manufactured by rolling-chemical milling process, which is usually faced with the problem of geometric accuracy caused by springback. In most cases, the methods of manual adjustment and multiple roll bending are used to control or eliminate the springback. However, these methods can cause the increase of product cost and cycle, and lead to material performance degradation. Therefore, it is of significance to precisely control the springback of rolling-chemical milling process. In this paper, using the method of experiment and numerical simulation on rolling-chemical milling process, the simulation model for rolling-chemical milling process of 2060-T8 aluminum-lithium alloy skin was established and testified by the comparison between numerical simulation and experiment results for the validity. Then, based on the numerical simulation model, the relative technological parameters which influence on the curvature of the skin panel were analyzed. Finally, the prediction of springback and the compensation can be realized by controlling the process parameters.

14 CFR 29.519 - Hull type rotorcraft: Water-based and amphibian.

Code of Federal Regulations, 2010 CFR

2010-01-01

... at zero forward speed in likely pitch and roll attitudes which result in critical design loadings... forward velocities from zero up to 30 knots in likely pitch, roll, and yaw attitudes and with a vertical...

A Proposal to Localize Fermi GBM GRBs Through Coordinated Scanning of the GBM Error Circle via Optical Telescopes

NASA Technical Reports Server (NTRS)

Ukwatta, T. N.; Linnemann, J. T.; Tollefson, K.; Abeysekara, A. U.; Bhat, P. N.; Sonbas, E.; Gehrels, N.

2011-01-01

We investigate the feasibility of implementing a system that will coordinate ground-based optical telescopes to cover the Fermi GBM Error Circle (EC). The aim of the system is to localize GBM detected GRBs and facilitate multi-wavelength follow-up from space and ground. This system will optimize the observing locations in the GBM EC based on individual telescope location, Field of View (FoV) and sensitivity. The proposed system will coordinate GBM EC scanning by professional as well as amateur astronomers around the world. The results of a Monte Carlo simulation to investigate the feasibility of the project are presented.

2. RW Meyer Sugar Mill: 18761899. Threeroll sugar mill, oneton ...

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

2. RW Meyer Sugar Mill: 1876-1899. Three-roll sugar mill, one-ton daily processing capacity. Manufactured by Edwin Maw, Liverpool, England, ca. 1855-1870. View: Top roll and one bottom roll, mill housing or cheeks, and spur pinion gears. The broken projection on the mill beside the bottom roll indicates the location of the cane tray. The cane juice crushed from the cane flowed into the juice tray below the bottom rolls. It then flowed into a wooden gutter and through a short tunnel in the mill's masonry enclosure and on to the boiling house for further processing. The opening at the base of the masency wall (In the photograph) is where the gutter ran from the mill to the boiling house. - R. W. Meyer Sugar Mill, State Route 47, Kualapuu, Maui County, HI

Transient and steady state viscoelastic rolling contact

NASA Technical Reports Server (NTRS)

Padovan, J.; Paramadilok, O.

1985-01-01

Based on moving total Lagrangian coordinates, a so-called traveling Hughes type contact strategy is developed. Employing the modified contact scheme in conjunction with a traveling finite element strategy, an overall solution methodology is developed to handle transient and steady viscoelastic rolling contact. To verify the scheme, the results of both experimental and analytical benchmarking is presented. The experimental benchmarking includes the handling of rolling tires up to their upper bound behavior, namely the standing wave response.

Roll-to-Roll printed large-area all-polymer solar cells with 5% efficiency based on a low crystallinity conjugated polymer blend

NASA Astrophysics Data System (ADS)

Gu, Xiaodan; Zhou, Yan; Gu, Kevin; Kurosawa, Tadanori; Yan, Hongping; Wang, Cheng; Toney, Micheal; Bao, Zhenan

The challenge of continuous printing in high efficiency large-area organic solar cells is a key limiting factor for their widespread adoption. We present a materials design concept for achieving large-area, solution coated all-polymer bulk heterojunction (BHJ) solar cells with stable phase separation morphology between the donor and acceptor. The key concept lies in inhibiting strong crystallization of donor and acceptor polymers, thus forming intermixed, low crystallinity and mostly amorphous blends. Based on experiments using donors and acceptors with different degree of crystallinity, our results showed that microphase separated donor and acceptor domain sizes are inversely proportional to the crystallinity of the conjugated polymers. This methodology of using low crystallinity donors and acceptors has the added benefit of forming a consistent and robust morphology that is insensitive to different processing conditions, allowing one to easily scale up the printing process from a small scale solution shearing coater to a large-scale continuous roll-to-roll (R2R) printer. We were able to continuously roll-to-roll slot die print large area all-polymer solar cells with power conversion efficiencies of 5%, with combined cell area up to 10 cm2. This is among the highest efficiencies realized with R2R coated active layer organic materials on flexible substrate. DOE BRIDGE sunshot program. Office of Naval Research.

Roll-to-Roll Printed Large-Area All-Polymer Solar Cells with 5% Efficiency Based on a Low Crystallinity Conjugated Polymer Blend

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

Gu, Xiaodan; Zhou, Yan; Gu, Kevin

The challenge of continuous printing in high-efficiency large-area organic solar cells is a key limiting factor for their widespread adoption. We present a materials design concept for achieving large-area, solution-coated all-polymer bulk heterojunction solar cells with stable phase separation morphology between the donor and acceptor. The key concept lies in inhibiting strong crystallization of donor and acceptor polymers, thus forming intermixed, low crystallinity, and mostly amorphous blends. Based on experiments using donors and acceptors with different degree of crystallinity, the results show that microphase separated donor and acceptor domain sizes are inversely proportional to the crystallinity of the conjugated polymers.more » This particular methodology of using low crystallinity donors and acceptors has the added benefit of forming a consistent and robust morphology that is insensitive to different processing conditions, allowing one to easily scale up the printing process from a small-scale solution shearing coater to a large-scale continuous roll-to-roll (R2R) printer. Large-area all-polymer solar cells are continuously roll-to-roll slot die printed with power conversion efficiencies of 5%, with combined cell area up to 10 cm 2. This is among the highest efficiencies realized with R2R-coated active layer organic materials on flexible substrate.« less

Roll-to-Roll Printed Large-Area All-Polymer Solar Cells with 5% Efficiency Based on a Low Crystallinity Conjugated Polymer Blend

DOE PAGES

Gu, Xiaodan; Zhou, Yan; Gu, Kevin; ...

2017-03-07

The challenge of continuous printing in high-efficiency large-area organic solar cells is a key limiting factor for their widespread adoption. We present a materials design concept for achieving large-area, solution-coated all-polymer bulk heterojunction solar cells with stable phase separation morphology between the donor and acceptor. The key concept lies in inhibiting strong crystallization of donor and acceptor polymers, thus forming intermixed, low crystallinity, and mostly amorphous blends. Based on experiments using donors and acceptors with different degree of crystallinity, the results show that microphase separated donor and acceptor domain sizes are inversely proportional to the crystallinity of the conjugated polymers.more » This particular methodology of using low crystallinity donors and acceptors has the added benefit of forming a consistent and robust morphology that is insensitive to different processing conditions, allowing one to easily scale up the printing process from a small-scale solution shearing coater to a large-scale continuous roll-to-roll (R2R) printer. Large-area all-polymer solar cells are continuously roll-to-roll slot die printed with power conversion efficiencies of 5%, with combined cell area up to 10 cm 2. This is among the highest efficiencies realized with R2R-coated active layer organic materials on flexible substrate.« less

Rolling dry-coupled transducers for ultrasonic inspections of aging aircraft structures

NASA Astrophysics Data System (ADS)

Komsky, Igor N.

2004-07-01

Some advanced aircraft materials or coatings are porous or otherwise sensitive to the application of water, gel, or some other ultrasonic couplants. To overcome the problems associated with the liquid coupling medium, dry-coupled rolling modules were developed at Northwestern University for the transmission of both longitudinal and transverse ultrasonic waves at frequencies up to 10 MHz. Dry-coupled ultrasonic modules contain solid core internal stators and solid or flexible external rotors with the flexible polymer substrates. Two types of the dry-coupled modules are under development. Cylindrical base transducer modules include solid core cylindrical rotors with flexible polymer substrates that rotate around the stators with ultrasonic elements. Dry-coupled modules with elongated bases contain solid core stators and flexible track-like polymer substrates that rotate around the stators as rotors of the modules. The elongated base modules have larger contact interfaces with the inspection surface in comparison with the cylindrical base modules. Some designs of the dry-coupled rolling modules contain several ultrasonic elements with different incident angles or a variable angle unit for rapid adjustments of incident angles. The prototype dry-coupled rolling modules were integrated with the portable ultrasonic inspection systems and tested on a number of Boeing aircraft structures.

Diboron compound-based organic light-emitting diodes with high efficiency and reduced efficiency roll-off

NASA Astrophysics Data System (ADS)

Wu, Tien-Lin; Huang, Min-Jie; Lin, Chih-Chun; Huang, Pei-Yun; Chou, Tsu-Yu; Chen-Cheng, Ren-Wu; Lin, Hao-Wu; Liu, Rai-Shung; Cheng, Chien-Hong

2018-04-01

Organic light-emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) materials are promising for the realization of highly efficient light emitters. However, such devices have so far suffered from efficiency roll-off at high luminance. Here, we report the design and synthesis of two diboron-based molecules, CzDBA and tBuCzDBA, which show excellent TADF properties and yield efficient OLEDs with very low efficiency roll-off. These donor-acceptor-donor (D-A-D) type and rod-like compounds concurrently generate TADF with a photoluminescence quantum yield of 100% and an 84% horizontal dipole ratio in the thin film. A green OLED based on CzDBA exhibits a high external quantum efficiency of 37.8 ± 0.6%, a current efficiency of 139.6 ± 2.8 cd A-1 and a power efficiency of 121.6 ± 3.1 lm W-1 with an efficiency roll-off of only 0.3% at 1,000 cd m-2. The device has a peak emission wavelength of 528 nm and colour coordinates of the Commission International de ĺEclairage (CIE) of (0.31, 0.61), making it attractive for colour-display applications.

A fault diagnosis scheme for rolling bearing based on local mean decomposition and improved multiscale fuzzy entropy

NASA Astrophysics Data System (ADS)

Li, Yongbo; Xu, Minqiang; Wang, Rixin; Huang, Wenhu

2016-01-01

This paper presents a new rolling bearing fault diagnosis method based on local mean decomposition (LMD), improved multiscale fuzzy entropy (IMFE), Laplacian score (LS) and improved support vector machine based binary tree (ISVM-BT). When the fault occurs in rolling bearings, the measured vibration signal is a multi-component amplitude-modulated and frequency-modulated (AM-FM) signal. LMD, a new self-adaptive time-frequency analysis method can decompose any complicated signal into a series of product functions (PFs), each of which is exactly a mono-component AM-FM signal. Hence, LMD is introduced to preprocess the vibration signal. Furthermore, IMFE that is designed to avoid the inaccurate estimation of fuzzy entropy can be utilized to quantify the complexity and self-similarity of time series for a range of scales based on fuzzy entropy. Besides, the LS approach is introduced to refine the fault features by sorting the scale factors. Subsequently, the obtained features are fed into the multi-fault classifier ISVM-BT to automatically fulfill the fault pattern identifications. The experimental results validate the effectiveness of the methodology and demonstrate that proposed algorithm can be applied to recognize the different categories and severities of rolling bearings.

Strategic Framing Study Circles: toward a gold standard of framing pedagogy.

PubMed

Feinberg, Jane

2009-01-01

This article explains how communities of practice have been developed as part of FrameWorks' field-building efforts. Strategic Framing Study Circles, as they are known, have been conducted with four statewide coalitions, one group of national organizations, and an emerging regional coalition. The goal of each community of practice is to build among participants a solid base of framing skills and competencies and to help them understand that despite varied organizational agendas, they can share a frame to tremendous collective advantage.

Quality Circles at Wilford Hall U.S.A.F. Medical Center, Lackland Air Force Base, Texas: Some Preliminary Findings

DTIC Science & Technology

1982-08-01

relationships which can be identified from one sample population and generalized to cause and effect in different persons, settings, and times...affect the cause-and-effect relationship which one can draw with a civilian group? Will it be pos- sible to generalize about other groups within... relationship about quality circles obtained in a military health care facility be generalized to a civil- ian one? Can a causal relationship about quality

Quality Circles: An Innovative Program to Improve Military Hospitals

DTIC Science & Technology

1982-08-01

quality control. However, Dr. Kaoru Ishikawa is credited with starting the first "Quality Control Circles" and registering them with the Japanese Union of...McGregor and Abraham Maslow into a unique style of management. In 1962 Dr. Ishikawa , a professor at Tokyo University, developed the QC concept based on...RECOMMENDATIONS Conclusions The QC concept has come a long way since Dr. Ishikawa gave it birth in 1962. It has left an enviable record of success along its

Distortion theorems for polynomials on a circle

NASA Astrophysics Data System (ADS)

Dubinin, V. N.

2000-12-01

Inequalities for the derivatives with respect to \\varphi=\\arg z the functions \\operatorname{Re}P(z), \\vert P(z)\\vert^2 and \\arg P(z) are established for an algebraic polynomial P(z) at points on the circle \\vert z\\vert=1. These estimates depend, in particular, on the constant term and the leading coefficient of the polynomial P(z) and improve the classical Bernstein and Turan inequalities. The method of proof is based on the techniques of generalized reduced moduli.

Postnatal haloperidol eliminates the deficit in circling behavior produced by prenatal exposure to the same drug.

PubMed

Wolansky, Marcelo Javier; Soiza-Reilly, Mariano; Fossati, Mariana; Azcurra, Julio Marcos

2004-01-01

Up to 35% of pregnant women take psychotropic drugs at least once during gestation [Austin and Mitchell, 1998]. From concurrent animal and human evidence, it has been proposed that exposure to several psychoactive medications in utero or during lactation increases the risk for permanent brain disorders. Present preventive or therapy practices applied on humans for this type of long-lasting behavioral alterations are mainly based on empirical results. Here, we test an experimental approach designed to counteract a circling performance deficit that appears in Sprague-Dawley rats at puberty on exposure to the dopaminergic blocker haloperidol (HAL) during gestation [J.L. Brusés, J.M. Azcurra, The circling training: A behavioral paradigm for functional teratology testing, in: P.M. Conn (Ed.), Paradigms for the study of behavior, Acad. Press, New York, 1993, pp. 166-179. Method Neurosci. 14]. Gestational exposure to HAL (GD 5-18, 2.5 mg/kg/day ip) induced the expected circling activity decrease in the offspring at the fifth week of life. When prenatal exposure to HAL was continued through lactation (PD5-21, 1.5 mg/kg/day ip), rats otherwise showed a control-like circling performance. No difference was yet found between lactation-only, HAL-exposed pups and saline (SAL)-treated controls (n=8 each group). We further performed saturating (3H)-spiroperidol (SPI) binding assays on striatal P2 membrane fractions 2 months later. The dopamine-type D2-specific binding results suggested that above circling behavior findings could be partially explained by enduring HAL-induced neurochemical changes. The role of critical periods of sensitivity as transient windows for opportunistic therapies for behavioral teratology is discussed. Copyright 2004 Elsevier Inc.

Optimizing care in osteoporosis: The Canadian quality circle project

PubMed Central

Ioannidis, George; Thabane, Lehana; Gafni, Amiram; Hodsman, Anthony; Kvern, Brent; Johnstone, Dan; Plumley, Nathalie; Salach, Lena; Jiwa, Famida; Adachi, Jonathan D; Papaioannou, Alexandra

2008-01-01

Background While the Osteoporosis Canada 2002 Canadian guidelines provided evidence based strategies in preventing, diagnosing, and managing this condition, publication and distribution of guidelines have not, in and of themselves, been shown to alter physicians clinical approaches. We hypothesize that primary care physicians enrolled in the Quality Circle project would change their patient management of osteoporosis in terms of awareness of osteoporosis risk factors and bone mineral density testing in accordance with the guidelines. Methods The project consisted of five Quality Circle phases that included: 1) Training & Baseline Data Collection, 2) First Educational Intervention & First Follow-Up Data Collection 3) First Strategy Implementation Session, 4) Final Educational Intervention & Final Follow-up Data Collection, and 5) Final Strategy Implementation Session. A total of 340 circle members formed 34 quality circles and participated in the study. The generalized estimating equations approach was used to model physician awareness of risk factors for osteoporosis and appropriate utilization of bone mineral density testing pre and post educational intervention (first year of the study). Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated. Results After the 1st year of the study, physicians' certainty of their patients' risk factor status increased. Certainty varied from an OR of 1.4 (95% CI: 1.1, 1.8) for prior vertebral fracture status to 6.3 (95% CI: 2.3, 17.9) for prior hip fracture status. Furthermore, bone mineral density testing increased in high risk as compared with low risk patients (OR: 1.4; 95% CI: 1.2, 1.7). Conclusion Quality Circle methodology was successful in increasing both physicians' awareness of osteoporosis risk factors and appropriate bone mineral density testing in accordance with the 2002 Canadian guidelines. PMID:18828906

11. DETAIL SHOWING ROLLING ENGINE DECK AND NORTHEAST TRUSS OF ...

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

11. DETAIL SHOWING ROLLING ENGINE DECK AND NORTHEAST TRUSS OF SUPERSTRUCTURE. Looking northeast. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

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.

Support Air and Space Expeditionary Forces. Analysis of Combat Support Basing Options

DTIC Science & Technology

2004-01-01

Mahyar A . Amouzegar, Robert S. Tripp, Ronald G. McGarve Edward W Chan C. Robert Roll, Jr. _77 Ap L_ L; Reý PROJECT AIR FORCE - Supporting Air and Space...Expeditionary Forces Analysis of Combat Support Basing Options Mahyar A . Amouzegar Robert S. Tripp Ronald G. McGarvey Edward W. Chan C. Robert Roll...support basing options / Mahyar A . Amouzegar ... [et al. p. cm. "’MG-261." Indudes bibliographical references. ISBN 0-8330-3675-0 (pbk.) 1. Air bases

Collision-based energetic comparison of rolling and hopping over obstacles

PubMed Central

Iida, Fumiya

2018-01-01

Locomotion of machines and robots operating in rough terrain is strongly influenced by the mechanics of the ground-machine interactions. A rolling wheel in terrain with obstacles is subject to collisional energy losses, which is governed by mechanics comparable to hopping or walking locomotion. Here we investigate the energetic cost associated with overcoming an obstacle for rolling and hopping locomotion, using a simple mechanics model. The model considers collision-based interactions with the ground and the obstacle, without frictional losses, and we quantify, analyse, and compare the sources of energetic costs for three locomotion strategies. Our results show that the energetic advantages of the locomotion strategies are uniquely defined given the moment of inertia and the Froude number associated with the system. We find that hopping outperforms rolling at larger Froude numbers and vice versa. The analysis is further extended for a comparative study with animals. By applying size and inertial properties through an allometric scaling law of hopping and trotting animals to our models, we found that the conditions at which hopping becomes energetically advantageous to rolling roughly corresponds to animals’ preferred gait transition speeds. The energetic collision losses as predicted by the model are largely verified experimentally. PMID:29538459

Liquid sensing capability of rolled-up tubular optical microcavities: a theoretical study.

PubMed

Zhao, Fangyuan; Zhan, Tianrong; Huang, Gaoshan; Mei, Yongfeng; Hu, Xinhua

2012-10-07

Rolled-up tubular optical microcavities are a novel type of optical sensor for identifying different liquids and monitoring single cells. Based on a Mie scattering method, we systematically study the optical resonances and liquid sensing capability of microtubes. Analytical formulas are presented to calculate the resonant wavelengths λ(r), Q factors, sensitivities S and figures of merit QS. Both ideal and rolled-up microtubes are considered for different optical materials in tube walls (refractive indices ranging from 1.5 to 2.5) and for three setups: tube-in-liquid, hollow-tube-in-liquid and liquid-in-tube. It is found that for rolled-up microtubes, the highest QS can be achieved by using the liquid-in-tube setup and very thin wall thicknesses. A maximal sensitivity is found in the case of the liquid cylinder. Our theory well explains a recent experiment under the setup of tube-in-liquid. It is also found that, although it describes the case of tube-in-liquid well, the waveguide approximation approach is not suitable for the case of liquid-in-tube. The results could be useful to design better optofluidic devices based on rolled-up microtubes.

Analysis of roll-stamped light guide plate fabricated with laser-ablated stamper

NASA Astrophysics Data System (ADS)

Na, Hyunjun; Hong, Seokkwan; Kim, Jongsun; Hwang, Jeongho; Joo, Byungyun; Yoon, Kyunghwan; Kang, Jeongjin

2017-12-01

LGP (light guide plate) is one of the major components of LCD (liquid crystal display), and it makes surface illumination for LCD backlit. LGP is a transparent plastic plate usually produced by injection molding process. On the back of LGP there are micron size patterns for extraction of light. Recently a roll-stamping process has achieved the high mass productivity of thinner LGPs. In order to fabricate optical patterns on LGPs, a fabricating tool called as a stamper is used. Micro patterns on metallic stampers are made by several micro machining processes such as chemical etching, LIGA-reflow, and laser ablation. In this study, a roll-stamping process by using a laser ablated metallic stamper was dealt with in consideration of the compatibility with the roll-stamping process. LGP fabricating tests were performed using a roll-stamping process with four different roll pressures. Pattern shapes on the stamper fabricated by laser ablation and transcription ratios of the roll-stamping process were analyzed, and LGP luminance was evaluated. Based on the evaluation, optical simulation model for LGP was made and simulation accuracy was evaluated. Simulation results showed good agreements with optical performance of LGPs in the brightness and uniformity. It was also shown that the roll-stamped LGP has the possibility of better optical performance than the conventional injection molded LGP. It was also shown that the roll-stamped LGP with the laser ablated stamper is potential to have better optical performance than the conventional injection molded LGP.

Numerical simulation of turbulent flow and heat transfer in the wedge-shaped liquid metal pool of a twin-roll caster

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

Seyedein, S.H.; Hasan, H.

1997-03-01

Controlled flow and heat transfer are important for the quality of a strip in a twin-roll continuous casting process. A numerical study was carried out to investigate the two-dimensional turbulent flow and heat transfer in the liquid stainless-steel-filled wedge-shaped cavity formed by the two counterrotating rolls in a twin-roll continuous casting system. The turbulent characteristics of the flow were modeled using a low-Reynolds-number {kappa}-{epsilon} turbulence model due to Launder and Sharma. The arbitrary nature of the computational domain was accounted for through the use of a nonorthogonal boundary-fitted coordinate system on a staggered grid. A control-volume-based finite difference scheme wasmore » used to solve the transformed transport equations. This study is primarily focused on elucidating the inlet superheat dissipation in the melt pool with the rolls being maintained at a constant liquidus temperature of the steel. A parametric study was carried out to ascertain the effect of the inlet superheat, the casting speed, and the roll gap at the nip of the rotating rolls on the flow and heat transfer characteristics. The velocity fields show two counterrotating recirculation zones in the upstream region. The local Nusselt number on the roll surface shows significant variations. The contours of temperature and turbulent viscosity show the complex nature of the turbulent transport phenomena to be expected in a twin-roll casting process.« less

Profiling procedure for disk cutter to generate the male rotor, screw compressors component, using the “Substitute Family Circle” - graphic method in AUTOCAD environment

NASA Astrophysics Data System (ADS)

Popa, CL; Popa, V.

2016-11-01

This paper proposes a profiling method for the tool which generates the helical groove of male rotor, screw compressor component. The method is based on a complementary theorem of surfaces enveloping - "Substitute Family Circles Method”. The specific theorem of family circles of substitution has been applied using AUTOCAD graphics design environment facility. The frontal view of the male rotor, screw compressor component, has been determinate knowing the transverse profile of female rotor, and using this theorem of "Substitute Family Circle". The three-dimensional model of the rotor makes possible to apply the same theorem, leading to the surface of revolution enveloping the helical surface. An application will be also presented to determine the axial profile of the disk cutter, numeric and graphics, following the proposed algorithm.

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

A tilt and roll device for automated correction of rotational setup errors.

PubMed

Hornick, D C; Litzenberg, D W; Lam, K L; Balter, J M; Hetrick, J; Ten Haken, R K

1998-09-01

A tilt and roll device has been developed to add two additional degrees of freedom to an existing treatment table. This device allows computer-controlled rotational motion about the inferior-superior and left-right patient axes. The tilt and roll device comprises three supports between the tabletop and base. An automotive type universal joint welded to the end of a steel pipe supports the center of the table. Two computer-controlled linear electric actuators utilizing high accuracy stepping motors support the foot of table and control the tilt and roll of the tabletop. The current system meets or exceeds all pre-design specifications for precision, weight capacity, rigidity, and range of motion.

Lunar surface engineering properties experiment definition. Volume 2: Mechanics of rolling sphere-soil slope interaction

NASA Technical Reports Server (NTRS)

Hovland, H. J.; Mitchell, J. K.

1971-01-01

The soil deformation mode under the action of a rolling sphere (boulder) was determined, and a theory based on actual soil failure mechanism was developed which provides a remote reconnaissance technique for study of soil conditions using boulder track observations. The failure mechanism was investigated by using models and by testing an instrumented spherical wheel. The wheel was specifically designed to measure contact pressure, but it also provided information on the failure mechanism. Further tests included rolling some 200 spheres down sand slopes. Films were taken of the rolling spheres, and the tracks were measured. Implications of the results and reevaluation of the lunar boulder tracks are discussed.

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

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...

SASS Applied to Optimum Work Roll Profile Selection in the Hot Rolling of Wide Steel

NASA Astrophysics Data System (ADS)

Nolle, Lars

The quality of steel strip produced in a wide strip rolling mill depends heavily on the careful selection of initial ground work roll profiles for each of the mill stands in the finishing train. In the past, these profiles were determined by human experts, based on their knowledge and experience. In previous work, the profiles were successfully optimised using a self-organising migration algorithm (SOMA). In this research, SASS, a novel heuristic optimisation algorithm that has only one control parameter, has been used to find the optimum profiles for a simulated rolling mill. The resulting strip quality produced using the profiles found by SASS is compared with results from previous work and the quality produced using the original profile specifications. The best set of profiles found by SASS clearly outperformed the original set and performed equally well as SOMA without the need of finding a suitable set of control parameters.

Rolling motion of an elastic cylinder induced by elastic strain gradients

NASA Astrophysics Data System (ADS)

Chen, Lei; Chen, Shaohua

2014-10-01

Recent experiment shows that an elastic strain gradient field can be utilized to transport spherical particles on a stretchable substrate by rolling, inspired by which a generalized plane-strain Johnson-Kendall-Roberts model is developed in this paper in order to verify possible rolling of an elastic cylinder adhering on an elastic substrate subject to a strain gradient. With the help of contact mechanics, closed form solutions of interface tractions, stress intensity factors, and corresponding energy release rates in the plane-strain contact model are obtained, based on which a possible rolling motion of an elastic cylinder induced by strain gradients is found and the criterion for the initiation of rolling is established. The theoretical prediction is consistent well with the existing experimental observation. The result should be helpful for understanding biological transport mechanisms through muscle contractions and the design of transport systems with strain gradient.

Development of a continuous roll-to-roll processing system for mass production of plastic optical film

NASA Astrophysics Data System (ADS)

Chang, Chih-Yuan; Tsai, Meng-Hsun

2015-12-01

This paper reports a highly effective method for the mass production of large-area plastic optical films with a microlens array pattern based on a continuous roll-to-roll film extrusion and roller embossing process. In this study, a thin steel mold with a micro-circular hole array pattern is fabricated by photolithography and a wet chemical etching process. The thin steel mold was then wrapped onto a metal cylinder to form an embossing roller mold. During the roll-to-roll process operation, a thermoplastic raw material (polycarbonate grains) was put into the barrel of the plastic extruder with a flat T-die. Then, the molten polymer film was extruded and immediately pressed against the surface of the embossing roller mold. Under the proper processing conditions, the molten polymer will just partially fill the micro-circular holes of the mold and due to surface tension form a convex lens surface. A continuous plastic optical film with a microlens array pattern was obtained. Experiments are carried out to investigate the effect of plastic microlens formation on the roll-to-roll process. Finally, the geometrical and optical properties of the fabricated plastic optical film were measured and proved satisfactory. This technique shows great potential for the mass production of large-area plastic optical films with a microlens array pattern.

Quantitative metrics for evaluating the phased roll-out of clinical information systems.

PubMed

Wong, David; Wu, Nicolas; Watkinson, Peter

2017-09-01

We introduce a novel quantitative approach for evaluating the order of roll-out during phased introduction of clinical information systems. Such roll-outs are associated with unavoidable risk due to patients transferring between clinical areas using both the old and new systems. We proposed a simple graphical model of patient flow through a hospital. Using a simple instance of the model, we showed how a roll-out order can be generated by minimising the flow of patients from the new system to the old system. The model was applied to admission and discharge data acquired from 37,080 patient journeys at the Churchill Hospital, Oxford between April 2013 and April 2014. The resulting order was evaluated empirically and produced acceptable orders. The development of data-driven approaches to clinical Information system roll-out provides insights that may not necessarily be ascertained through clinical judgment alone. Such methods could make a significant contribution to the smooth running of an organisation during the roll-out of a potentially disruptive technology. Unlike previous approaches, which are based on clinical opinion, the approach described here quantitatively assesses the appropriateness of competing roll-out strategies. The data-driven approach was shown to produce strategies that matched clinical intuition and provides a flexible framework that may be used to plan and monitor Clinical Information System roll-out. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

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

GIS based evaluation of crop suitability for agricultural sustainability around Kolaghat thermal power plant, India.

PubMed

Adak, Subhas; Adhikari, Kalyan; Brahmachari, Koushik

2016-09-01

Fly ash exhaust from Kolaghat thermal power plant, West Bengal, India,?? affects the areas within the radius of 3 - 4 km. Land information system indicated that surface texture within 4 km was silty loam and clay content increased with increase of distance. Soil pH was alkaline (7.58-8.01) in affected circles, whereas soil was acidic (5.95-6.41) in rest of block. Organic carbon (OC) is roving from 0.36 to 0.64% in the nearer circles which is lesser from others. The present Crop suitability analysis revealed that 96.98 % area was suitable (S1) for maize, sesame, jute, whereas these were cultivated in less than 1% of land. Flowers are the best suitable (S1) in 88.9 % but it was grown in 6.02 % area.? The present rice area within 4 km of KTPP is showing moderately suitable (S2) and S1 for the rest. Wheat is moderately suitable (S2) in the almost all the circles.? Cultivation of vegetable crops is limited in the affected circles while the highly suitable (S1) comprises 67.49 % for the remaining areas though it covered only 6.01 % of the block.? This evaluation precisely improves more than 300% from the earlier cropping intensity of 177.95 %. Suitability based land use allocation serves as stepping stone to promote agricultural sustainability. Geographic information system (GIS) model has been developed to assess site specific crop suitability for sustainable agricultural planning.

Leaf-rolling in maize crops: from leaf scoring to canopy-level measurements for phenotyping

PubMed Central

Madec, Simon; Irfan, Kamran; Lopez, Jeremy; Comar, Alexis; Hemmerlé, Matthieu; Dutartre, Dan; Praud, Sebastien; Tixier, Marie Helene

2018-01-01

Abstract Leaf rolling in maize crops is one of the main plant reactions to water stress that can be visually scored in the field. However, leaf-scoring techniques do not meet the high-throughput requirements needed by breeders for efficient phenotyping. Consequently, this study investigated the relationship between leaf-rolling scores and changes in canopy structure that can be determined by high-throughput remote-sensing techniques. Experiments were conducted in 2015 and 2016 on maize genotypes subjected to water stress. Leaf-rolling was scored visually over the whole day around the flowering stage. Concurrent digital hemispherical photographs were taken to evaluate the impact of leaf-rolling on canopy structure using the computed fraction of intercepted diffuse photosynthetically active radiation, FIPARdif. The results showed that leaves started to roll due to water stress around 09:00 h and leaf-rolling reached its maximum around 15:00 h (the photoperiod was about 05:00–20:00 h). In contrast, plants maintained under well-watered conditions did not show any significant rolling during the same day. A canopy-level index of rolling (CLIR) is proposed to quantify the diurnal changes in canopy structure induced by leaf-rolling. It normalizes for the differences in FIPARdif between genotypes observed in the early morning when leaves are unrolled, as well as for yearly effects linked to environmental conditions. Leaf-level rolling score was very strongly correlated with changes in canopy structure as described by the CLIR (r2=0.86, n=370). The daily time course of rolling was characterized using the amplitude of variation, and the rate and the timing of development computed at both the leaf and canopy levels. Results obtained from eight genotypes common between the two years of experiments showed that the amplitude of variation of the CLIR was the more repeatable trait (Spearman coefficient ρ=0.62) as compared to the rate (ρ=0.29) and the timing of development (ρ=0.33). The potential of these findings for the development of a high-throughput method for determining leaf-rolling based on aerial drone observations are considered. PMID:29617837

Simulation of the hot rolling of steel with direct iteration

NASA Astrophysics Data System (ADS)

Hanoglu, Umut; Šarler, Božidar

2017-10-01

In this study a simulation system based on the meshless Local Radial Basis Function Collocation Method (LRBFCM) is applied for the hot rolling of steel. Rolling is a complex, 3D, thermo-mechanical problem; however, 2D cross-sectional slices are used as computational domains that are aligned with the rolling direction and no heat flow or strain is considered in the direction that is orthogonal to the slices. For each predefined position with respect to the rolling direction, the solution procedure is repeated until the slice reaches the final rolling position. Collocation nodes are initially distributed over the domain and boundaries of the initial slice. A local solution is achieved by considering the overlapping influence domains with either 5 or 7 nodes. Radial Basis Functions (RBFs) are used for the temperature discretization in the thermal model and displacement discretization in the mechanical model. The meshless solution procedure does not require a mesh-generation algorithm in the classic sense. Strong-form mechanical and thermal models are run for each slice regarding the contact with the roll's surface. Ideal plastic material behavior is considered for the mechanical results, where the nonlinear stress-strain relation is solved with a direct iteration. The majority of the Finite Element Model (FEM) simulations, including commercial software, use a conventional Newton-Raphson algorithm. However, direct iteration is chosen here due to its better compatibility with meshless methods. In order to overcome any unforeseen stability issues, the redistribution of the nodes by Elliptic Node Generation (ENG) is applied to one or more slices throughout the simulation. The rolling simulation presented here helps the user to design, test and optimize different rolling schedules. The results can be seen minutes after the simulation's start in terms of temperature, displacement, stress and strain fields as well as important technological parameters, like the roll-separating forces, roll toque, etc. An example of a rolling simulation, in which an initial size of 110x110 mm steel is rolled to a round bar with 80 mm diameter, is shown in Fig. 3. A user-friendly computer application for industrial use is created by using the C# and .NET frameworks.

Rolling-element bearings in China: From ancient times to the 20th century

NASA Astrophysics Data System (ADS)

Sun, Lie; Li, Ang

2016-03-01

The development of rolling-element bearings in China has spanned a long period. Based on several typical and important cases, the present article reconstructs the history of rolling-element bearings in China by dividing it into four stages according to the various characteristics of the bearings. The first stage represents the origin of rolling bearings in China, which remains controversial because of several suspected races and cages that were likely the components of bearings more than a millennium ago. At the second stage, a type of simple roller bearing was used for astronomical instruments not later than the 13th century based on clear philological and physical evidence. A similar bearing was also applied to an abridged armillary in the 17th century. Another type of spherical thrust bearings with rolling elements, which is a key component of a traditional Chinese windmill, could support a rotating shaft that moves rotationally and at an angle. At the third stage, the Chinese began studying and using the so-called Europeanstyle bearing since the 17th century. Moreover, over the last 100 years, the modern rolling bearing industry was gradually established in China, particularly because of the technology transfer from the Soviet Union in the 1950s. At the fourth stage, the Chinese government initiated the relatively rapid development of bearing technology. The government launched the "bearing movement" from the 1950s to the 1960s to establish the modern bearing industry and to promote rolling bearings as replacement for traditional sliding bearings. Furthermore, a number of large professional factories and institutions in China have continually introduced advanced technology and equipment. At present, these companies and institutions play a significant role in the international bearing industry.

Oblique view to the northwest detailing four overhead rolling doors ...

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

Oblique view to the northwest detailing four overhead rolling doors on the northeast elevation - Over-the-Horizon Backscatter Radar Network, Mountain Home Air Force Operations Building, On Desert Street at 9th Avenue Mountain Home Air Force Base, Mountain Home, Elmore County, ID

Five-minute synthesis of silver nanowires and their roll-to-roll processing for large-area organic light emitting diodes.

PubMed

Sim, Hwansu; Kim, Chanho; Bok, Shingyu; Kim, Min Ki; Oh, Hwisu; Lim, Guh-Hwan; Cho, Sung Min; Lim, Byungkwon

2018-06-18

Silver (Ag) nanowires (NWs) are promising building blocks for flexible transparent electrodes, which are key components in fabricating soft electronic devices such as flexible organic light emitting diodes (OLEDs). Typically, Ag NWs have been synthesized using a polyol method, but it still remains a challenge to produce high-aspect-ratio Ag NWs via a simple and rapid process. In this work, we developed a modified polyol method and newly found that the addition of propylene glycol to ethylene glycol-based polyol synthesis facilitated the growth of Ag NWs, allowing the rapid production of long Ag NWs with high aspect ratios of about 2000 in a high yield (∼90%) within 5 min. Transparent electrodes fabricated with our Ag NWs exhibited performance comparable to that of an indium tin oxide-based electrode. With these Ag NWs, we successfully demonstrated the fabrication of a large-area flexible OLED with dimensions of 30 cm × 15 cm using a roll-to-roll process.

Mechanics based model for predicting structure-induced rolling resistance (SRR) of the tire-pavement system

NASA Astrophysics Data System (ADS)

Shakiba, Maryam; Ozer, Hasan; Ziyadi, Mojtaba; Al-Qadi, Imad L.

2016-11-01

The structure-induced rolling resistance of pavements, and its impact on vehicle fuel consumption, is investigated in this study. The structural response of pavement causes additional rolling resistance and fuel consumption of vehicles through deformation of pavement and various dissipation mechanisms associated with inelastic material properties and damping. Accurate and computationally efficient models are required to capture these mechanisms and obtain realistic estimates of changes in vehicle fuel consumption. Two mechanistic-based approaches are currently used to calculate vehicle fuel consumption as related to structural rolling resistance: dissipation-induced and deflection-induced methods. The deflection-induced approach is adopted in this study, and realistic representation of pavement-vehicle interactions (PVIs) is incorporated. In addition to considering viscoelastic behavior of asphalt concrete layers, the realistic representation of PVIs in this study includes non-uniform three-dimensional tire contact stresses and dynamic analysis in pavement simulations. The effects of analysis type, tire contact stresses, pavement viscoelastic properties, pavement damping coefficients, vehicle speed, and pavement temperature are then investigated.

Morpheus Lander Roll Control System and Wind Modeling

NASA Technical Reports Server (NTRS)

Gambone, Elisabeth A.

2014-01-01

The Morpheus prototype lander is a testbed capable of vertical takeoff and landing developed by NASA Johnson Space Center to assess advanced space technologies. Morpheus completed a series of flight tests at Kennedy Space Center to demonstrate autonomous landing and hazard avoidance for future exploration missions. As a prototype vehicle being tested in Earth's atmosphere, Morpheus requires a robust roll control system to counteract aerodynamic forces. This paper describes the control algorithm designed that commands jet firing and delay times based on roll orientation. Design, analysis, and testing are supported using a high fidelity, 6 degree-of-freedom simulation of vehicle dynamics. This paper also details the wind profiles generated using historical wind data, which are necessary to validate the roll control system in the simulation environment. In preparation for Morpheus testing, the wind model was expanded to create day-of-flight wind profiles based on data delivered by Kennedy Space Center. After the test campaign, a comparison of flight and simulation performance was completed to provide additional model validation.

High-precision register error control using active-motion-based roller in roll-to-roll gravure printing

NASA Astrophysics Data System (ADS)

Jung, Hoeryong; Nguyen, Ho Anh Duc; Choi, Jaeho; Yim, Hongsik; Shin, Kee-Hyun

2018-05-01

The roll-to-roll (R2R) gravure printing method is increasingly being utilized to fabricate electronic devices such as organic thin-film transistor (OTFT), radio-frequency identification (RFID) tags, and flexible PCB owing to its characteristics of high throughput and large area. High precision registration is crucial to satisfy the demand for device miniaturization, the improvement of resolution and accuracy. This paper presents a novel register control method that uses an active motion-based roller (AMBR) to reduce register error in R2R gravure printing. Instead of shifting the phase of the downstream printing roller, which leads to undesired tension disturbance, the 1 degree-of-freedom (1-DOF) mechanical device AMBR is used to compensate for web elongation by controlling its motion according to the register error. The performance of the proposed control method is verified through simulations and experiments, and the results show that the proposed register control method using the AMBR could maintain a register error under ±15 µm.

Ultra-wideband pose detection system for boom-type roadheader based on Caffery transform and Taylor series expansion

NASA Astrophysics Data System (ADS)

Fu, Shichen; Li, Yiming; Zhang, Minjun; Zong, Kai; Cheng, Long; Wu, Miao

2018-01-01

To realize unmanned pose detection of a coalmine boom-type roadheader, an ultra-wideband (UWB) pose detection system (UPDS) for a roadheader is designed, which consists of four UWB positioning base stations and three roadheader positioning nodes. The positioning base stations are used in turn to locate the positioning nodes of the roadheader fuselage. Using 12 sets of distance measurement information, a time-of-arrival (TOA) positioning model is established to calculate the 3D coordinates of three positioning nodes of the roadheader fuselage, and the three attitude angles (heading, pitch, and roll angles) of the roadheader fuselage are solved. A range accuracy experiment of a UWB P440 module was carried out in a narrow and closed tunnel, and the experiment data show that the mean error and standard deviation of the module can reach below 2 cm. Based on the TOA positioning model of the UPDS, we propose a fusion-positioning algorithm based on a Caffery transform and Taylor series expansion (CTFPA). We derived the complete calculation process, designed a flowchart, and carried out a simulation of CTFPA in MATLAB, comparing 1000 simulated positioning nodes of CTFPA and the Caffery positioning algorithm (CPA) for a 95 m long tunnel. The positioning error field of the tunnel was established, and the influence of the spatial variation on the positioning accuracy of CPA and CTFPA was analysed. The simulation results show that, compared with CPA, the positioning accuracy of CTFPA is clearly improved, and the accuracy of each axis can reach more than 5 mm. The accuracy of the X-axis is higher than that of the Y- and Z-axes. In section X-Y of the tunnel, the root mean square error (RMSE) contours of CTFPA are clear and orderly, and with an increase in the measuring distance, RMSE increases linearly. In section X-Z, the RMSE contours are concentric circles, and the variation ratio is nonlinear.

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)

White blood cell segmentation by circle detection using electromagnetism-like optimization.

PubMed

Cuevas, Erik; Oliva, Diego; Díaz, Margarita; Zaldivar, Daniel; Pérez-Cisneros, Marco; Pajares, Gonzalo

2013-01-01

Medical imaging is a relevant field of application of image processing algorithms. In particular, the analysis of white blood cell (WBC) images has engaged researchers from fields of medicine and computer vision alike. Since WBCs can be approximated by a quasicircular form, a circular detector algorithm may be successfully applied. This paper presents an algorithm for the automatic detection of white blood cells embedded into complicated and cluttered smear images that considers the complete process as a circle detection problem. The approach is based on a nature-inspired technique called the electromagnetism-like optimization (EMO) algorithm which is a heuristic method that follows electromagnetism principles for solving complex optimization problems. The proposed approach uses an objective function which measures the resemblance of a candidate circle to an actual WBC. Guided by the values of such objective function, the set of encoded candidate circles are evolved by using EMO, so that they can fit into the actual blood cells contained in the edge map of the image. Experimental results from blood cell images with a varying range of complexity are included to validate the efficiency of the proposed technique regarding detection, robustness, and stability.

White Blood Cell Segmentation by Circle Detection Using Electromagnetism-Like Optimization

PubMed Central

Oliva, Diego; Díaz, Margarita; Zaldivar, Daniel; Pérez-Cisneros, Marco; Pajares, Gonzalo

2013-01-01

Medical imaging is a relevant field of application of image processing algorithms. In particular, the analysis of white blood cell (WBC) images has engaged researchers from fields of medicine and computer vision alike. Since WBCs can be approximated by a quasicircular form, a circular detector algorithm may be successfully applied. This paper presents an algorithm for the automatic detection of white blood cells embedded into complicated and cluttered smear images that considers the complete process as a circle detection problem. The approach is based on a nature-inspired technique called the electromagnetism-like optimization (EMO) algorithm which is a heuristic method that follows electromagnetism principles for solving complex optimization problems. The proposed approach uses an objective function which measures the resemblance of a candidate circle to an actual WBC. Guided by the values of such objective function, the set of encoded candidate circles are evolved by using EMO, so that they can fit into the actual blood cells contained in the edge map of the image. Experimental results from blood cell images with a varying range of complexity are included to validate the efficiency of the proposed technique regarding detection, robustness, and stability. PMID:23476713

A U.K. cost-benefit analysis of circles of support and accountability interventions.

PubMed

Elliott, Ian A; Beech, Anthony R

2013-06-01

Circles of Support and Accountability (CoSA) aim to augment sex offender risk management at the point of community reentry by facilitating "Circles" of volunteers who provide support, guidance, and advice, while ensuring that the offender remains accountable for their actions. In this study, the authors provide (a) a rapid evidence assessment of the effectiveness of CoSA in reducing reoffending, and (b) a U.K. cost-benefit analysis for CoSA when compared to the criminal justice costs of reoffending. From the study analysis, the average cost of a "Circle" was estimated to be £11,303 per annum and appears to produce a 50% reduction in reoffending (sexual and nonsexual), as the estimated cost of reoffending was estimated to be £147,161 per offender, per annum. Based on a hypothetical cohort of 100 offenders--50 of whom receive CoSA and 50 of whom do not--investment in CoSA appears to provide a cost saving of £23,494 and a benefit-cost ratio of 1.04. Accounting for estimates that the full extent of the cost to society may be 5 to 10 times the tangible costs substantially increases estimated cost savings related to CoSA.

Combined Activity of DCL2 and DCL3 Is Crucial in the Defense against Potato Spindle Tuber Viroid

PubMed Central

Katsarou, Konstantina; Mavrothalassiti, Eleni; Dermauw, Wannes; Van Leeuwen, Thomas; Kalantidis, Kriton

2016-01-01

Viroids are self replicating non-coding RNAs capable of infecting a wide range of plant hosts. They do not encode any proteins, thus the mechanism by which they escape plant defenses remains unclear. RNAi silencing is a major defense mechanism against virus infections, with the four DCL proteins being principal components of the pathway. We have used Nicotiana benthamiana as a model to study Potato spindle tuber viroid infection. This viroid is a member of the Pospiviroidae family and replicates in the nucleus via an asymmetric rolling circle mechanism. We have created knock-down plants for all four DCL genes and their combinations. Previously, we showed that DCL4 has a positive effect on PSTVd infectivity since viroid levels drop when DCL4 is suppressed. Here, we show that PSTVd levels remain decreased throughout infection in DCL4 knockdown plants, and that simultaneous knockdown of DCL1, DCL2 or DCL3 together with DCL4 cannot reverse this effect. Through infection of plants suppressed for multiple DCLs we further show that a combined suppression of DCL2 and DCL3 has a major effect in succumbing plant antiviral defense. Based on our results, we further suggest that Pospoviroids may have evolved to be primarily processed by DCL4 as it seems to be a DCL protein with less detrimental effects on viroid infectivity. These findings pave the way to delineate the complexity of the relationship between viroids and plant RNA silencing response. PMID:27732664

Error baseline rates of five sample preparation methods used to characterize RNA virus populations.

PubMed

Kugelman, Jeffrey R; Wiley, Michael R; Nagle, Elyse R; Reyes, Daniel; Pfeffer, Brad P; Kuhn, Jens H; Sanchez-Lockhart, Mariano; Palacios, Gustavo F

2017-01-01

Individual RNA viruses typically occur as populations of genomes that differ slightly from each other due to mutations introduced by the error-prone viral polymerase. Understanding the variability of RNA virus genome populations is critical for understanding virus evolution because individual mutant genomes may gain evolutionary selective advantages and give rise to dominant subpopulations, possibly even leading to the emergence of viruses resistant to medical countermeasures. Reverse transcription of virus genome populations followed by next-generation sequencing is the only available method to characterize variation for RNA viruses. However, both steps may lead to the introduction of artificial mutations, thereby skewing the data. To better understand how such errors are introduced during sample preparation, we determined and compared error baseline rates of five different sample preparation methods by analyzing in vitro transcribed Ebola virus RNA from an artificial plasmid-based system. These methods included: shotgun sequencing from plasmid DNA or in vitro transcribed RNA as a basic "no amplification" method, amplicon sequencing from the plasmid DNA or in vitro transcribed RNA as a "targeted" amplification method, sequence-independent single-primer amplification (SISPA) as a "random" amplification method, rolling circle reverse transcription sequencing (CirSeq) as an advanced "no amplification" method, and Illumina TruSeq RNA Access as a "targeted" enrichment method. The measured error frequencies indicate that RNA Access offers the best tradeoff between sensitivity and sample preparation error (1.4-5) of all compared methods.

Error baseline rates of five sample preparation methods used to characterize RNA virus populations

PubMed Central

Kugelman, Jeffrey R.; Wiley, Michael R.; Nagle, Elyse R.; Reyes, Daniel; Pfeffer, Brad P.; Kuhn, Jens H.; Sanchez-Lockhart, Mariano; Palacios, Gustavo F.

2017-01-01

Individual RNA viruses typically occur as populations of genomes that differ slightly from each other due to mutations introduced by the error-prone viral polymerase. Understanding the variability of RNA virus genome populations is critical for understanding virus evolution because individual mutant genomes may gain evolutionary selective advantages and give rise to dominant subpopulations, possibly even leading to the emergence of viruses resistant to medical countermeasures. Reverse transcription of virus genome populations followed by next-generation sequencing is the only available method to characterize variation for RNA viruses. However, both steps may lead to the introduction of artificial mutations, thereby skewing the data. To better understand how such errors are introduced during sample preparation, we determined and compared error baseline rates of five different sample preparation methods by analyzing in vitro transcribed Ebola virus RNA from an artificial plasmid-based system. These methods included: shotgun sequencing from plasmid DNA or in vitro transcribed RNA as a basic “no amplification” method, amplicon sequencing from the plasmid DNA or in vitro transcribed RNA as a “targeted” amplification method, sequence-independent single-primer amplification (SISPA) as a “random” amplification method, rolling circle reverse transcription sequencing (CirSeq) as an advanced “no amplification” method, and Illumina TruSeq RNA Access as a “targeted” enrichment method. The measured error frequencies indicate that RNA Access offers the best tradeoff between sensitivity and sample preparation error (1.4−5) of all compared methods. PMID:28182717

Begomovirus diversity in tomato crops and weeds in Ecuador and the detection of a recombinant isolate of rhynchosia golden mosaic Yucatan virus infecting tomato.

PubMed

Paz-Carrasco, Lenin C; Castillo-Urquiza, Gloria P; Lima, Alison T M; Xavier, Cesar A D; Vivas-Vivas, Leticia M; Mizubuti, Eduardo S G; Zerbini, F Murilo

2014-08-01

Viral diseases caused by begomoviruses are of economic importance due to their adverse effects on the production of tropical and subtropical crops. In Ecuador, despite reports of significant infestations of Bemisia tabaci in the late 1990s, only very recently has a begomovirus, tomato leaf deformation virus (ToLDeV, also present in Peru), been reported in tomato. ToLDeV is the first monopartite begomovirus discovered that originated in the Americas, and its presence in Ecuador highlights the need for a wider survey of tomato-infecting begomoviruses in this country. Tomato and weed samples were collected in 2010 and 2011 in six provinces of Ecuador, and begomovirus genomes were cloned and sequenced using a rolling-circle-amplification-based approach. Most tomato samples from the provinces of Guayas, Loja, Manabi and Santa Elena were infected with tomato leaf deformation virus (ToLDeV). One sample from Manabi had a triple infection with ToLDeV, rhynchosia golden mosaic Yucatan virus (RhGMYuV) and an isolate that was a recombinant between the two. A new begomovirus was detected in another tomato sample from Manabi. Samples of Rhynchosia sp. from the provinces of Guayas and Manabi were infected by RhGMYuV. These results indicate not only the prevalence of ToLDeV in tomato in Ecuador but also the presence of other viruses, albeit at a much lower frequency.

Critical Issues for Cu(InGa)Se2 Solar Cells on Flexible Polymer Web

NASA Technical Reports Server (NTRS)

Eser, Erten; Fields, Shannon; Shafarman, William; Birkmire, Robert

2007-01-01

Elemental in-line evaporation on glass substrates has been a viable process for the large-area manufacture of CuInSe2-based photovoltaics, with module efficiencies as high as 12.7% [1]. However, lightweight, flexible CuInSe2-based modules are attractive in a number of applications, such as space power sources. In addition, flexible substrates have an inherent advantage in manufacturability in that they can be deposited in a roll-to-roll configuration allowing continuous, high yield, and ultimately lower cost production. As a result, high-temperature polymers have been used as substrates in depositing CuInSe2 films [2]. Recently, efficiency of 14.1% has been reported for a Cu(InGa)Se2-based solar cell on a polyimide substrate [3]. Both metal foil and polymer webs have been used as substrates for Cu(InGa)Se2-based photovoltaics in a roll-to-roll configuration with reasonable success [4,5]. Both of these substrates do not allow, readily, the incorporation of Na into the Cu(InGa)Se2 film which is necessary for high efficiency devices [3]. In addition, polymer substrates, can not be used at temperatures that are optimum for Cu(InGa)Se2 deposition. However, unlike metal foils, they are electrically insulating, simplifying monolithically-integrated module fabrication and are not a source of impurities diffusing into the growing film. The Institute of Energy Conversion (IEC) has modified its in-line evaporation system [6] from deposition onto glass substrates to roll-to-roll deposition onto polyimide (PI) film in order to investigate key issues in the deposition of large-area Cu(InGa)Se2 films on flexible polymer substrates. This transition presented unexpected challenges that had to be resolved. In this paper, two major problems, spitting from the Cu source and the cracking of Mo back contact film, will be discussed and the solution to each will be presented.

[Does implementation of benchmarking in quality circles improve the quality of care of patients with asthma and reduce drug interaction?].

PubMed

Kaufmann-Kolle, Petra; Szecsenyi, Joachim; Broge, Björn; Haefeli, Walter Emil; Schneider, Antonius

2011-01-01

The purpose of this cluster-randomised controlled trial was to evaluate the efficacy of quality circles (QCs) working either with general data-based feedback or with an open benchmark within the field of asthma care and drug-drug interactions. Twelve QCs, involving 96 general practitioners from 85 practices, were randomised. Six QCs worked with traditional anonymous feedback and six with an open benchmark. Two QC meetings supported with feedback reports were held covering the topics "drug-drug interactions" and "asthma"; in both cases discussions were guided by a trained moderator. Outcome measures included health-related quality of life and patient satisfaction with treatment, asthma severity and number of potentially inappropriate drug combinations as well as the general practitioners' satisfaction in relation to the performance of the QC. A significant improvement in the treatment of asthma was observed in both trial arms. However, there was only a slight improvement regarding inappropriate drug combinations. There were no relevant differences between the group with open benchmark (B-QC) and traditional quality circles (T-QC). The physicians' satisfaction with the QC performance was significantly higher in the T-QCs. General practitioners seem to take a critical perspective about open benchmarking in quality circles. Caution should be used when implementing benchmarking in a quality circle as it did not improve healthcare when compared to the traditional procedure with anonymised comparisons. Copyright © 2011. Published by Elsevier GmbH.

Ghost circles in lattice Aubry-Mather theory

NASA Astrophysics Data System (ADS)

Mramor, Blaz; Rink, Bob

Monotone lattice recurrence relations such as the Frenkel-Kontorova lattice, arise in Hamiltonian lattice mechanics, as models for ferromagnetism and as discretization of elliptic PDEs. Mathematically, they are a multi-dimensional counterpart of monotone twist maps. Such recurrence relations often admit a variational structure, so that the solutions x:Z→R are the stationary points of a formal action function W(x). Given any rotation vector ω∈R, classical Aubry-Mather theory establishes the existence of a large collection of solutions of ∇W(x)=0 of rotation vector ω. For irrational ω, this is the well-known Aubry-Mather set. It consists of global minimizers and it may have gaps. In this paper, we study the parabolic gradient flow {dx}/{dt}=-∇W(x) and we will prove that every Aubry-Mather set can be interpolated by a continuous gradient-flow invariant family, the so-called 'ghost circle'. The existence of these ghost circles is known in dimension d=1, for rational rotation vectors and Morse action functions. The main technical result of this paper is therefore a compactness theorem for lattice ghost circles, based on a parabolic Harnack inequality for the gradient flow. This implies the existence of lattice ghost circles of arbitrary rotation vectors and for arbitrary actions. As a consequence, we can give a simple proof of the fact that when an Aubry-Mather set has a gap, then this gap must be filled with minimizers, or contain a non-minimizing solution.

Incipient fault feature extraction of rolling bearings based on the MVMD and Teager energy operator.

PubMed

Ma, Jun; Wu, Jiande; Wang, Xiaodong

2018-06-04

Aiming at the problems that the incipient fault of rolling bearings is difficult to recognize and the number of intrinsic mode functions (IMFs) decomposed by variational mode decomposition (VMD) must be set in advance and can not be adaptively selected, taking full advantages of the adaptive segmentation of scale spectrum and Teager energy operator (TEO) demodulation, a new method for early fault feature extraction of rolling bearings based on the modified VMD and Teager energy operator (MVMD-TEO) is proposed. Firstly, the vibration signal of rolling bearings is analyzed by adaptive scale space spectrum segmentation to obtain the spectrum segmentation support boundary, and then the number K of IMFs decomposed by VMD is adaptively determined. Secondly, the original vibration signal is adaptively decomposed into K IMFs, and the effective IMF components are extracted based on the correlation coefficient criterion. Finally, the Teager energy spectrum of the reconstructed signal of the effective IMF components is calculated by the TEO, and then the early fault features of rolling bearings are extracted to realize the fault identification and location. Comparative experiments of the proposed method and the existing fault feature extraction method based on Local Mean Decomposition and Teager energy operator (LMD-TEO) have been implemented using experimental data-sets and a measured data-set. The results of comparative experiments in three application cases show that the presented method can achieve a fairly or slightly better performance than LMD-TEO method, and the validity and feasibility of the proposed method are proved. Copyright © 2018. Published by Elsevier Ltd.

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.

Effects of La2O3 Content and Rolling on Microstructure and Mechanical Properties of ODS Molybdenum Alloys

NASA Astrophysics Data System (ADS)

Ma, Jingling; Li, Wuhui; Wang, Guangxin; Li, Yaqiong; Guo, Hongbo; Zhao, Zeliang; Li, Wei

2017-10-01

In order to study the effects of La2O3 content and rolling on microstructure and mechanical properties of Mo-La2O3 alloys, Mo-0.5% (1%) La2O3 alloys were prepared by liquid-solid doping technique, subsequently rolled either by a single-direction rolling or a cross-rolling. As a result, three different materials were prepared for this study. After being annealed at 1800 °C, the single-directionally rolled Mo-1% La2O3 alloy shows the best mechanical properties in terms of strength, hardness, and sagging deformation among the three materials. This is attributed to the observation that the alloy is only recovered with a microstructure of subgrains and dislocations. The single-directionally rolled Mo-0.5% La2O3 exhibits the worst mechanical property among the three materials. In this material, coarse grains, but no subgrains and dislocations, can be observed after annealing, indicating that it is fully recrystallized. For the cross-rolled Mo-1% La2O3 alloy, grains of dispersed sizes, but no dislocations, are visible after annealing, implying that this alloy is partially recrystallized. Accordingly, the mechanical property of this material is in between the other two materials. Thus, the mechanical properties of the three materials can be well understood based on OM, SEM, and TEM results. Overall, the single-directionally rolled Mo-1% La2O3 alloy possesses good mechanical properties and is more suitable for high-temperature applications.

Layer texture of hot-rolled BCC metals and its significance for stress-corrosion cracking of main gas pipelines

NASA Astrophysics Data System (ADS)

Perlovich, Yu. A.; Isaenkova, M. G.; Krymskaya, O. A.; Morozov, N. S.

2016-10-01

Based on data of X-ray texture analysis of hot-rolled BCC materials it was shown that the layerwise texture inhomogeneity of products is formed during their manufacturing. The effect can be explained by saturation with interstitial impurities of the surface layer, resulting in dynamical deformation aging (DDA). DDA prevents the dislocation slip under rolling and leads to an increase of lattice parameters in the external layer. The degree of arising inhomogeneity correlates with the tendency of hot-rolled sheets and obtained therefrom tubes to stress-corrosion cracking under exploitation, since internal layers have a compressive effect on external layers, and prevents opening of corrosion cracks at the tube surface.

Fabrication of flexible oriented magnetic thin films with large in-plane uniaxial anisotropy by roll-to-roll nanoimprint lithography

NASA Astrophysics Data System (ADS)

Thantirige, Rukshan M.; John, Jacob; Pradhan, Nihar R.; Carter, Kenneth R.; Tuominen, Mark T.

2016-06-01

Here, we report wafer scale fabrication of densely packed Fe nanostripe-based magnetic thin films on a flexible substrate and their magnetic anisotropy properties. We find that Fe nanostripes exhibit large in-plane uniaxial anisotropy and nearly square hysteresis loops with energy products (BHmax) exceeding 3 MGOe at room temperature. High density Fe nanostripes were fabricated on 70 nm flexible polyethylene terephthalate (PET) gratings, which were made by a roll-to-roll (R2R) UV nanoimprint lithography technique. We observed large in-plane uniaxial anisotropies along the long dimension of nanostripes that can be attributed to the shape. Temperature dependent hysteresis measurements confirm that the magnetization reversal is driven by non-coherent rotation reversal processes.

The Space Shuttle Endeavour's drag chute deploys to slow the orbiter as it rolls out on Runway 22 at Edwards Air Force Base at the conclusion of its 14-day STS-111 mission to the International Space Station

NASA Image and Video Library

2002-06-19

The Space Shuttle Endeavour's drag chute deploys to slow the orbiter as it rolls out on Runway 22 at Edwards Air Force Base at the conclusion of its 14-day STS-111 mission to the International Space Station.

Sea Basing and Alternatives for Deploying and Sustaining Ground Combat Forces

DTIC Science & Technology

2007-07-01

speed roll-on/roll-off ship (top) and an intratheater high - speed vessel (bottom) are shown alongside a notional mobile landing platform (center...F), might be needed to fully support sea-based ground forces. Those other ships could include tankers and high - speed ships for spe- cial cargo . The...maritime prepositioning squadron; T-HSS = high - speed ship ; TBD = to be determined. Vehicles Cargo Aircraft (Thousands of (Thousands

Visualization Techniques Applied to 155-mm Projectile Analysis

DTIC Science & Technology

2014-11-01

semi-infinite Riemann problems are used in CFD++ to provide upwind flux information to the underlying transport scheme. Approximate Riemann solvers ...characteristics-based inflow/outflow boundary condition, which is based on solving a Riemann problem at the boundary. 2.3 Numerics Rolling/spinning is the...the solution files generated by the computational fluid dynamics (CFD) solver for the time-accurate rolling simulations at each timestep for the Mach

Culture Circles in adolescent empowerment for the prevention of violence

PubMed Central

Monteiro, Estela Maria Leite Meirelles; Neto, Waldemar Brandão; de Lima, Luciane Soares; de Aquino, Jael Maria; Gontijo, Daniela Tavares; Pereira, Beatriz Oliveira

2015-01-01

An action research based on Paulo Freire's Culture Circles was developed to implement a health education intervention involving adolescents, in collective knowledge construction about strategies for the prevention of violence. The data collection in the Culture Circles involved 11 adolescents and included observation and field diary, photographic records and recording. The educational action aroused a critical socio-political and cultural position in the adolescents towards the situations of vulnerability to violence, including the guarantee of human rights, justice and the combat of inequities; changes in the social relations, combat against discrimination and intolerance; expansion of access and reorientation of health services through intersectoral public policies. The intervention empowered the group of adolescents for the prevention of violence and permitted the inclusion of health professionals in the school context, from an interdisciplinary perspective, contributing to the establishment of social support and protection networks. PMID:25931647

Experiences in reconciling risk management and restorative justice: how circles of support and accountability work restoratively in the risk society.

PubMed

Hannem, Stacey

2013-03-01

Circles of Support and Accountability (COSA) is a restorative justice-based model that originated in Canada in the mid-1990s for the postincarceration reintegration of those who have offended sexually. Although the roots of COSA are in restorative justice philosophy, the program has also found favour, to some degree, with organisations such as police services and corrections that are traditionally concerned more with protecting community safety than with the ideals of restorative justice. Informed by the author's research and personal experience as a COSA volunteer, and analysis of recent and historical representations of COSA, this article explores theoretically how the development of the COSA initiative has been influenced by the seemingly disparate concerns of both the restorative justice and community protection movements, and examines the importance of balancing these paradigms in the everyday practices of circles.

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…

Impact of Wind Shear Characteristics on Roll Structure in Idealized Hurricane Boundary Layers

NASA Astrophysics Data System (ADS)

Wang, S.; Jiang, Q.

2016-12-01

The hurricane boundary layer (HBL) is well known for its critical role in evolutions of tropical cyclones (TCs) as the air-sea interaction represents both the most important source and sink of the moist available energy and the kinetic energy, respectively. One of the frequently occurring features in the HBL is horizontal roll vortices, which have quasi-two dimensional coherent and banded structure extending from the surface to the top of the HBL. It is believed that this highly coherent structure, caused by the inflection point instability in the basic wind profiles, plays an important role in organizing turbulent transport. To understand this role, large-eddy simulations are conducted to investigate how the wind shear characteristics such as the shear strength and inflection-point level can impact the roll structure in terms of its spectral characteristics and turbulence organization. A mean wind profile nudging approach is used in the simulations to maintain the required mean wind shear without directly affecting turbulent motions. Enhancing the radial wind shear expands the roll horizontal scale and strengthens the roll's kinetic energy. Increasing the inflection-point level tends to produce a narrow and sharp peak in the power spectrum at the wavelength consistent with the roll spacing indicated by the instantaneous turbulent fields. The spectral tangential momentum flux, in particular, reaches a strong peak value at the roll wavelength. In contrast, the spectral radial momentum flux obtains its maximum at the wavelength that is usually shorter than the roll's, suggesting that the roll radial momentum transport is less efficient than the tangential. The most robust rolls are produced in a simulation with the highest inflection-point level and strong radial wind shear. Based on the spectral analysis, the roll-scale contribution to the turbulent momentum flux can reach 40% in the middle of the boundary layer.

Fluid-structure interaction of a rolling restrained body of revolution at high angles of attack

NASA Astrophysics Data System (ADS)

Degani, D.; Ishay, M.; Gottlieb, O.

2017-03-01

The current work investigates numerically rolling instabilities of a free-to-roll slender rigid-body of revolution placed in a wind tunnel at a high angle of attack. The resistance to the roll moment is represented by a linear torsion spring and equivalent linear damping representing friction in the bearings of a simulated wind tunnel model. The body is subjected to a three-dimensional, compressible, laminar flow. The full Navier-Stokes equations are solved using the second-order implicit finite difference Beam-Warming scheme, adapted to a curvilinear coordinate system, whereas the coupled structural second order equation of motion for roll is solved by a fourth-order Runge-Kutta method. The body consists of a 3.5-diameter tangent ogive forebody with a 7.0-diameter long cylindrical afterbody extending aft of the nose-body junction to x/D = 10.5. We describe in detail the investigation of three angles of attack 20°, 40°, and 65°, at a Reynolds number of 30 000 (based on body diameter) and a Mach number of 0.2. Three distinct configurations are investigated as follows: a fixed body, a free-to-roll body with a weak torsion spring, and a free-to-roll body with a strong torsion spring. For each angle of attack the free-to-roll configuration portrays a distinct and different behavior pattern, including bi-stable limit-cycle oscillations. The bifurcation structure incorporates both large and small amplitude periodic roll oscillations where the latter lose their periodicity with increasing stiffness of the restraining spring culminating with distinct quasiperiodic oscillations. We note that removal of an applied upstream disturbance for a restrained body does not change the magnitude or complexity of the oscillations or of the flow patterns along the body. Depending on structure characteristics and flow conditions even a small rolling moment coefficient at the relatively low angle of attack of 20° may lead to large amplitude resonant roll oscillations.

The record of iceberg roll generated waves from sediments and seismics

NASA Astrophysics Data System (ADS)

Rosser, N. J.; Szczucinski, W.; Strzelecki, M.; Long, A. J.; Norman, E. C.; Dunning, S.; Drewniak, M.

2013-12-01

Iceberg-roll tsunamis in coastal settings have been observed to generate significant local waves, that hold potential to be recorded in coastal depositional records. Capturing the past magnitude and frequency of such events remains challenging, hindered by a lack of a good understanding of the nature, recurrence and scale of iceberg rolls, and more specifically those rolls that generate waves. Here we consider the sedimentary evidence for iceberg rolls in West Central Greenland, based upon survey of depositional environments in a range of open and confined coastal environments. We examine both an open 80 km fjord setting, and a series of confined ice-marginal beaches. We combine a detailed interpretation of sediment deposits from shore-normal transects with wider-scale high-resolution terrestrial laser scanning of sediments. Our sites - Vaigat, which separates Disko Island from the Nussuaq Peninsular, and the northern shore of Icefjord - both have a recent history of tsunamis, triggered variously by large rock avalanches, landslides and iceberg rolls. Icebergs in Vaigat and Icefjord are observed to undergo frequent failure and roll, generating - where circumstances permit - nearshore waves of meter-scale. To obtain a more detailed understanding of the likely recurrence of such iceberg roll waves and to consider their influence upon the preserved sedimentary record, we undertook an intensive 2-month monitoring campaign during sea-ice free conditions in summer 2013 to determine the patterns in the location, magnitude, frequency and timing of iceberg roll waves. Innovatively, using microseismic monitoring combined with time-lapse photography and weather monitoring, we derive a first-order model of the occurrence of iceberg roll waves. We then use this to inform our interpretation of deposits in these two environments, and consider the presence and absence of records of iceberg roll deposits in such settings. The study was funded by Polish National Science Centre grant No. 2011/01/B/ST10/01553.

High-Speed Rolling of AZ31 Magnesium Alloy Having Different Initial Textures

NASA Astrophysics Data System (ADS)

Onuki, Yusuke; Hara, Kenichiro; Utsunomiya, Hiroshi; Szpunar, Jerzy A.

2015-02-01

It is known that magnesium alloys can be rolled up to a large thickness reduction and develop a unique texture when the rolling speed is high (>1000 m/min). In order to understand the texture formation mechanism during high-strain-rate deformation, high-speed rolling of AZ31 magnesium alloy samples having different initial textures was conducted. The main components of the textures after the rolling were the RD-split basal, which consisted of 10°-20° inclining basal poles from the normal direction toward the rolling direction of the sheet, regardless of the different initial textures. With preheating at 473 K, all the samples were rolled without cracking while all were cracked when preheating was not applied. The optical micrographs and EBSD measurements showed a significant amount of twins and the cracks that developed along the shear bands consisted with laminated twins. Based on the texture simulation using the visco-plastic self-consistent model, it is concluded that the rapid development of the RD-split basal component from the initial basal alignment along the transverse direction was attributable to the tension twinning, The effect of the initial texture on the crack formation can be explained by the activation of the twinning system.

Calcium and zirconium as texture modifiers during rolling and annealing of magnesium–zinc alloys

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

Bohlen, Jan, E-mail: jan.bohlen@hzg.de; Wendt, Joachim; Nienaber, Maria

2015-03-15

Rolling experiments were carried out on a ternary Mg–Zn–Ca alloy and its modification with zirconium. Short time annealing of as-rolled sheets is used to reveal the microstructure and texture development. The texture of the as-rolled sheets can be characterised by basal pole figures with split peak towards the rolling direction (RD) and a broad transverse angular spread of basal planes towards the transverse direction (TD). During annealing the RD split peaks as well as orientations in the sheet plane vanish whereas the distribution of orientations tilted towards the TD remains. It is shown in EBSD measurements that during rolling bandsmore » of twin containing structures form. During subsequent annealing basal orientations close to the sheet plane vanish based on a grain nucleation and growth mechanism of recrystallisation. Orientations with tilt towards the TD remain in grains that do not undergo such a mechanism. The addition of Zr delays texture weakening. - Highlights: • Ca in Mg–Zn-alloys contributes to a significant texture weakening during rolling and annealing. • Grain nucleation and growth in structures consisting of twins explain a texture randomisation during annealing. • Grains with transverse tilt of basal planes preferentially do not undergo a grain nucleation and growth mechanism. • Zr delays the microstructure and texture development.« less

Resistance to Rolling in the Adhesive Contact of Two Elastic Spheres

NASA Technical Reports Server (NTRS)

Dominik, C.; Tielens, A. G. G. M.

1995-01-01

For the stability of agglomerates of micron sized particles it is of considerable importance to study the effects of tangential forces on the contact of two particles. If the particles can slide or roll easily over each other, fractal structures of these agglomerates will not be stable. We use the description of contact forces by Johnson, Kendall and Roberts, along with arguments based on the atomic structure of the surfaces in contact, in order to calculate the resistance to rolling in such a contact. It is shown that the contact reacts elastically to torque forces up to a critical bending angle. Beyond that, irreversible rolling occurs. In the elastic regime, the moment opposing the attempt to roll is proportional to the bending angle and to the pull-off force P(sub c). Young's modulus of the involved materials has hardly any influence on the results. We show that agglomerates of sub-micron sized particles will in general be quite rigid and even long chains of particles cannot be bent easily. For very small particles, the contact will rather break than allow for rolling. We further discuss dynamic properties such as the possibility of vibrations in this degree of freedom and the typical amount of rolling during a collision of two particles.

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.

Honoring children, mending the circle: cultural adaptation of trauma-focused cognitive-behavioral therapy for American Indian and Alaska native children.

PubMed

BigFoot, Dolores Subia; Schmidt, Susan R

2010-08-01

American Indians and Alaska Natives are vulnerable populations with significant levels of trauma exposure. The Indian Country Child Trauma Center developed an American Indian and Alaska Native (AI/AN) adaptation of the evidence-based child trauma treatment, trauma-focused cognitive-behavioral therapy. Honoring Children, Mending the Circle (HC-MC) guides the therapeutic process through a blending of AI/AN traditional teachings with cognitive-behavioral methods. The authors introduced the HC-MC treatment and illustrated its therapeutic tools by way of a case illustration.

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.

Parameters design of the dielectric elastomer spring-roll bending actuator (Conference Presentation)

NASA Astrophysics Data System (ADS)

Li, Jinrong; Liu, Liwu; Liu, Yanju; Leng, Jinsong

2017-04-01

Dielectric elastomers are novel soft smart material that could deform sustainably when subjected to external electric field. That makes dielectric elastomers promising materials for actuators. In this paper, a spring-roll actuator that would bend when a high voltage is applied was fabricated based on dielectric elastomer. Using such actuators as active parts, the flexible grippers and inchworm-inspired crawling robots were manufactured, which demonstrated some examples of applications in soft robotics. To guide the parameters design of dielectric elastomer based spring-roll bending actuators, the theoretical model of such actuators was established based on thermodynamic theories. The initial deformation and electrical induced bending angle of actuators were formulated. The failure of actuators was also analyzed considering some typical failure modes like electromechanical instability, electrical breakdown, loss of tension and maximum tolerant stretch. Thus the allowable region of actuators was determined. Then the bending angle-voltage relations and failure voltages of actuators with different parameters, including stretches of the dielectric elastomer film, number of active layers, and dimensions of spring, were investigated. The influences of each parameter on the actuator performances were discussed, providing meaningful guidance to the optical design of the spring-roll bending actuators.

High volume nanoscale roll-based imprinting using jet and flash imprint lithography

NASA Astrophysics Data System (ADS)

Ahn, Se Hyun; Miller, Mike; Yang, Shuqiang; Ganapathisubramanian, Maha; Menezes, Marlon; Singh, Vik; Choi, Jin; Xu, Frank; LaBrake, Dwayne; Resnick, Douglas J.; Sreenivasan, S. V.

2013-09-01

Extremely large-area roll-to-roll (R2R) manufacturing on flexible substrates is ubiquitous for applications such as paper and plastic processing. It combines the benefits of high speed and inexpensive substrates to deliver a commodity product at low cost. The challenge is to extend this approach to the realm of nanopatterning and realize similar benefits. In order to achieve low-cost nanopatterning, it is imperative to move toward high-speed imprinting, less complex tools, near zero waste of consumables, and low-cost substrates. We have developed a roll-based J-FIL process and applied it to a technology demonstrator tool, the LithoFlex 100, to fabricate large-area flexible bilayer wire-grid polarizers (WGPs) and high-performance WGPs on rigid glass substrates. Extinction ratios of better than 10,000 are obtained for the glass-based WGPs. Two simulation packages are also employed to understand the effects of pitch, aluminum thickness, and pattern defectivity on the optical performance of the WGP devices. It is determined that the WGPs can be influenced by both clear and opaque defects in the gratings; however, the defect densities are relaxed relative to the requirements of a high-density semiconductor device.

A High Precision Approach to Calibrate a Structured Light Vision Sensor in a Robot-Based Three-Dimensional Measurement System.

PubMed

Wu, Defeng; Chen, Tianfei; Li, Aiguo

2016-08-30

A robot-based three-dimensional (3D) measurement system is presented. In the presented system, a structured light vision sensor is mounted on the arm of an industrial robot. Measurement accuracy is one of the most important aspects of any 3D measurement system. To improve the measuring accuracy of the structured light vision sensor, a novel sensor calibration approach is proposed to improve the calibration accuracy. The approach is based on a number of fixed concentric circles manufactured in a calibration target. The concentric circle is employed to determine the real projected centres of the circles. Then, a calibration point generation procedure is used with the help of the calibrated robot. When enough calibration points are ready, the radial alignment constraint (RAC) method is adopted to calibrate the camera model. A multilayer perceptron neural network (MLPNN) is then employed to identify the calibration residuals after the application of the RAC method. Therefore, the hybrid pinhole model and the MLPNN are used to represent the real camera model. Using a standard ball to validate the effectiveness of the presented technique, the experimental results demonstrate that the proposed novel calibration approach can achieve a highly accurate model of the structured light vision sensor.