Branched RNA: A New Architecture for RNA Interference

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Anna Aviñó

2011-01-01

Full Text Available Branched RNAs with two and four strands were synthesized. These structures were used to obtain branched siRNA. The branched siRNA duplexes had similar inhibitory capacity as those of unmodified siRNA duplexes, as deduced from gene silencing experiments of the TNF-α protein. Branched RNAs are considered novel structures for siRNA technology, and they provide an innovative tool for specific gene inhibition. As the method described here is compatible with most RNA modifications described to date, these compounds may be further functionalized to obtain more potent siRNA derivatives and can be attached to suitable delivery systems.

Visualizing Transient Watson-Crick Like Mispairs in DNA and RNA Duplexes

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Kimsey, Isaac J.; Petzold, Katja; Sathyamoorthy, Bharathwaj; Stein, Zachary W.; Al-Hashimi, Hashim M.

2015-01-01

Rare tautomeric and anionic nucleobases are believed to play fundamental biological roles but their prevalence and functional importance has remained elusive because they exist transiently, in low-abundance, and involve subtle movements of protons that are difficult to visualize. Using NMR relaxation dispersion, we show that wobble dG•dT and rG•rU mispairs in DNA and RNA duplexes exist in dynamic equilibrium with short-lived, low-populated Watson-Crick like mispairs that are stabilized by rare enolic or anionic bases. These mispairs can evade Watson-Crick fidelity checkpoints and form with probabilities (10−3-10−5) that strongly imply a universal role in replication and translation errors. Our results indicate that rare tautomeric and anionic bases are widespread in nucleic acids, expanding their structural and functional complexity beyond that attainable with canonical bases. PMID:25762137

Visualizing transient Watson-Crick-like mispairs in DNA and RNA duplexes.

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Kimsey, Isaac J; Petzold, Katja; Sathyamoorthy, Bharathwaj; Stein, Zachary W; Al-Hashimi, Hashim M

2015-03-19

Rare tautomeric and anionic nucleobases are believed to have fundamental biological roles, but their prevalence and functional importance has remained elusive because they exist transiently, in low abundance, and involve subtle movements of protons that are difficult to visualize. Using NMR relaxation dispersion, we show here that wobble dG•dT and rG•rU mispairs in DNA and RNA duplexes exist in dynamic equilibrium with short-lived, low-populated Watson-Crick-like mispairs that are stabilized by rare enolic or anionic bases. These mispairs can evade Watson-Crick fidelity checkpoints and form with probabilities (10(-3) to 10(-5)) that strongly imply a universal role in replication and translation errors. Our results indicate that rare tautomeric and anionic bases are widespread in nucleic acids, expanding their structural and functional complexity beyond that attainable with canonical bases.

Sigma phase morphologies in cast and aged super duplex stainless steel

International Nuclear Information System (INIS)

Martins, Marcelo; Casteletti, Luiz Carlos

2009-01-01

Solution annealed and water quenched duplex and super duplex stainless steels are thermodynamically metastable systems at room temperature. These systems do not migrate spontaneously to a thermodynamically stable condition because an energy barrier separates the metastable and stable states. However, any heat input they receive, for example through isothermal treatment or through prolonged exposure to a voltaic arc in the welding process, cause them to reach a condition of stable equilibrium which, for super duplex stainless steels, means precipitation of intermetallic and carbide phases. These phases include the sigma phase, which is easily identified from its morphology, and its influence on the material's impact strength. The purpose of this work was to ascertain how 2-hour isothermal heat treatments at 920 deg. C and 980 deg. C affect the microstructure of ASTM A890/A890M GR 6A super duplex stainless steel. The sigma phase morphologies were found to be influenced by these two aging temperatures, with the material showing a predominantly lacy microstructure when heat treated at 920 deg. C and block-shaped when heat treated at 980 deg. C.

Distance-dependent duplex DNA destabilization proximal to G-quadruplex/i-motif sequences

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König, Sebastian L. B.; Huppert, Julian L.; Sigel, Roland K. O.; Evans, Amanda C.

2013-01-01

G-quadruplexes and i-motifs are complementary examples of non-canonical nucleic acid substructure conformations. G-quadruplex thermodynamic stability has been extensively studied for a variety of base sequences, but the degree of duplex destabilization that adjacent quadruplex structure formation can cause has yet to be fully addressed. Stable in vivo formation of these alternative nucleic acid structures is likely to be highly dependent on whether sufficient spacing exists between neighbouring duplex- and quadruplex-/i-motif-forming regions to accommodate quadruplexes or i-motifs without disrupting duplex stability. Prediction of putative G-quadruplex-forming regions is likely to be assisted by further understanding of what distance (number of base pairs) is required for duplexes to remain stable as quadruplexes or i-motifs form. Using oligonucleotide constructs derived from precedented G-quadruplexes and i-motif-forming bcl-2 P1 promoter region, initial biophysical stability studies indicate that the formation of G-quadruplex and i-motif conformations do destabilize proximal duplex regions. The undermining effect that quadruplex formation can have on duplex stability is mitigated with increased distance from the duplex region: a spacing of five base pairs or more is sufficient to maintain duplex stability proximal to predicted quadruplex/i-motif-forming regions. PMID:23771141

Improved Model for Predicting the Free Energy Contribution of Dinucleotide Bulges to RNA Duplex Stability.

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Tomcho, Jeremy C; Tillman, Magdalena R; Znosko, Brent M

2015-09-01

Predicting the secondary structure of RNA is an intermediate in predicting RNA three-dimensional structure. Commonly, determining RNA secondary structure from sequence uses free energy minimization and nearest neighbor parameters. Current algorithms utilize a sequence-independent model to predict free energy contributions of dinucleotide bulges. To determine if a sequence-dependent model would be more accurate, short RNA duplexes containing dinucleotide bulges with different sequences and nearest neighbor combinations were optically melted to derive thermodynamic parameters. These data suggested energy contributions of dinucleotide bulges were sequence-dependent, and a sequence-dependent model was derived. This model assigns free energy penalties based on the identity of nucleotides in the bulge (3.06 kcal/mol for two purines, 2.93 kcal/mol for two pyrimidines, 2.71 kcal/mol for 5'-purine-pyrimidine-3', and 2.41 kcal/mol for 5'-pyrimidine-purine-3'). The predictive model also includes a 0.45 kcal/mol penalty for an A-U pair adjacent to the bulge and a -0.28 kcal/mol bonus for a G-U pair adjacent to the bulge. The new sequence-dependent model results in predicted values within, on average, 0.17 kcal/mol of experimental values, a significant improvement over the sequence-independent model. This model and new experimental values can be incorporated into algorithms that predict RNA stability and secondary structure from sequence.

High-Resolution Crystal Structure of a Silver(I)-RNA Hybrid Duplex Containing Watson-Crick-like C-Silver(I)-C Metallo-Base Pairs.

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Kondo, Jiro; Tada, Yoshinari; Dairaku, Takenori; Saneyoshi, Hisao; Okamoto, Itaru; Tanaka, Yoshiyuki; Ono, Akira

2015-11-02

Metallo-base pairs have been extensively studied for applications in nucleic acid-based nanodevices and genetic code expansion. Metallo-base pairs composed of natural nucleobases are attractive because nanodevices containing natural metallo-base pairs can be easily prepared from commercially available sources. Previously, we have reported a crystal structure of a DNA duplex containing T-Hg(II)-T base pairs. Herein, we have determined a high-resolution crystal structure of the second natural metallo-base pair between pyrimidine bases C-Ag(I)-C formed in an RNA duplex. One Ag(I) occupies the center between two cytosines and forms a C-Ag(I)-C base pair through N3-Ag(I)-N3 linear coordination. The C-Ag(I)-C base pair formation does not disturb the standard A-form conformation of RNA. Since the C-Ag(I)-C base pair is structurally similar to the canonical Watson-Crick base pairs, it can be a useful building block for structure-based design and fabrication of nucleic acid-based nanodevices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Steric restrictions of RISC in RNA interference identified with size-expanded RNA nucleobases.

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Hernández, Armando R; Peterson, Larryn W; Kool, Eric T

2012-08-17

Understanding the interactions between small interfering RNAs (siRNAs) and the RNA-induced silencing complex (RISC), the key protein complex of RNA interference (RNAi), is of great importance to the development of siRNAs with improved biological and potentially therapeutic function. Although various chemically modified siRNAs have been reported, relatively few studies with modified nucleobases exist. Here we describe the synthesis and hybridization properties of siRNAs bearing size-expanded RNA (xRNA) nucleobases and their use as a novel and systematic set of steric probes in RNAi. xRNA nucleobases are expanded by 2.4 Å using benzo-homologation and retain canonical Watson-Crick base-pairing groups. Our data show that the modified siRNA duplexes display small changes in melting temperature (+1.4 to -5.0 °C); substitutions near the center are somewhat destabilizing to the RNA duplex, while substitutions near the ends are stabilizing. RNAi studies in a dual-reporter luciferase assay in HeLa cells revealed that xRNA nucleobases in the antisense strand reduce activity at some central positions near the seed region but are generally well tolerated near the ends. Most importantly, we observed that xRNA substitutions near the 3'-end increased activity over that of wild-type siRNAs. The data are analyzed in terms of site-dependent steric effects in RISC. Circular dichroism experiments show that single xRNA substitutions do not significantly distort the native A-form helical structure of the siRNA duplex, and serum stability studies demonstrated that xRNA substitutions protect siRNAs against nuclease degradation.

Probing of miniPEGγ-PNA-DNA Hybrid Duplex Stability with AFM Force Spectroscopy.

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Dutta, Samrat; Armitage, Bruce A; Lyubchenko, Yuri L

2016-03-15

Peptide nucleic acids (PNA) are synthetic polymers, the neutral peptide backbone of which provides elevated stability to PNA-PNA and PNA-DNA hybrid duplexes. It was demonstrated that incorporation of diethylene glycol (miniPEG) at the γ position of the peptide backbone increased the thermal stability of the hybrid duplexes (Sahu, B. et al. J. Org. Chem. 2011, 76, 5614-5627). Here, we applied atomic force microscopy (AFM) based single molecule force spectroscopy and dynamic force spectroscopy (DFS) to test the strength and stability of the hybrid 10 bp duplex. This hybrid duplex consisted of miniPEGγ-PNA and DNA of the same length (γ(MP)PNA-DNA), which we compared to a DNA duplex with a homologous sequence. AFM force spectroscopy data obtained at the same conditions showed that the γ(MP)PNA-DNA hybrid is more stable than the DNA counterpart, 65 ± 15 pN vs 47 ± 15 pN, respectively. The DFS measurements performed in a range of pulling speeds analyzed in the framework of the Bell-Evans approach yielded a dissociation constant, koff ≈ 0.030 ± 0.01 s⁻¹ for γ(MP)PNA-DNA hybrid duplex vs 0.375 ± 0.18 s⁻¹ for the DNA-DNA duplex suggesting that the hybrid duplex is much more stable. Correlating the high affinity of γ(MP)PNA-DNA to slow dissociation kinetics is consistent with prior bulk characterization by surface plasmon resonance. Given the growing interest in γ(MP)PNA as well as other synthetic DNA analogues, the use of single molecule experiments along with computational analysis of force spectroscopy data will provide direct characterization of various modifications as well as higher order structures such as triplexes and quadruplexes.

Hammerhead ribozyme activity and oligonucleotide duplex stability in mixed solutions of water and organic compounds

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Shu-ichi Nakano

2014-01-01

Full Text Available Nucleic acids are useful for biomedical targeting and sensing applications in which the molecular environment is different from that of a dilute aqueous solution. In this study, the influence of various types of mixed solutions of water and water-soluble organic compounds on RNA was investigated by measuring the catalytic activity of the hammerhead ribozyme and the thermodynamic stability of an oligonucleotide duplex. The compounds with a net neutral charge, such as poly(ethylene glycol, small primary alcohols, amide compounds, and aprotic solvent molecules, added at high concentrations changed the ribozyme-catalyzed RNA cleavage rate, with the magnitude of the effect dependent on the NaCl concentration. These compounds also changed the thermodynamic stability of RNA base pairs of an oligonucleotide duplex and its dependence on the NaCl concentration. Specific interactions with RNA molecules and reduced water activity could account for the inhibiting effects on the ribozyme catalysis and destabilizing effects on the duplex stability. The salt concentration dependence data correlated with the dielectric constant, but not with water activity, viscosity, and the size of organic compounds. This observation suggests the significance of the dielectric constant effects on the RNA reactions under molecular crowding conditions created by organic compounds.

Base Pair Opening in a Deoxynucleotide Duplex Containing a cis-syn Thymine Cyclobutane Dimer Lesion

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Wenke, Belinda B.; Huiting, Leah N.; Frankel, Elisa B.; Lane, Benjamin F.; Núñez, Megan E.

2014-01-01

The cis-syn thymine cyclobutane dimer is a DNA photoproduct implicated in skin cancer. We compared the stability of individual base pairs in thymine dimer-containing duplexes to undamaged parent 10-mer duplexes. UV melting thermodynamic measurements, CD spectroscopy, and 2D NOESY NMR spectroscopy confirm that the thymine dimer lesion is locally and moderately destabilizing within an overall B-form duplex conformation. We measured the rates of exchange of individual imino protons by NMR using magnetization transfer from water and determined the equilibrium constant for the opening of each base pair Kop. In the normal duplex Kop decreases from the frayed ends of the duplex toward the center, such that the central TA pair is the most stable with a Kop of 8×10−7. In contrast, base pair opening at the 5’T of the thymine dimer is facile. The 5’T of the dimer has the largest equilibrium constant (Kop =3×10−4) in its duplex, considerably larger than even the frayed penultimate base pairs. Notably, base pairing by the 3’T of the dimer is much more stable than by the 5’T, indicating that the predominant opening mechanism for the thymine dimer lesion is not likely to be flipping out into solution as a single unit. The dimer asymmetrically affects the stability of the duplex in its vicinity, destabilizing base pairing on its 5’ side more than on the 3’ side. The striking differences in base pair opening between parent and dimer duplexes occur independently of the duplex-single strand melting transitions. PMID:24328089

Probabilistic Medium Access Control for Full-Duplex Networks with Half-Duplex Clients

OpenAIRE

Chen, Shih-Ying; Huang, Ting-Feng; Lin, Kate Ching-Ju; Hong, H. -W. Peter; Sabharwal, Ashutosh

2016-01-01

The feasibility of practical in-band full-duplex radios has recently been demonstrated experimentally. One way to leverage full-duplex in a network setting is to enable three-node full-duplex, where a full- duplex access point (AP) transmits data to one node yet simultaneously receives data from another node. Such three-node full-duplex communication however introduces inter-client interference, directly impacting the full-duplex gain. It hence may not always be beneficial to enable three-nod...

Development of a lean duplex stainless steel

Energy Technology Data Exchange (ETDEWEB)

Liljas, M.; Johansson, P.; Liu Hui-Ping; Olsson, C.O.A. [Avesta Research Centre, Avesta (Sweden). Outokumpu Stainless

2008-06-15

The classic series of duplex stainless steels shows very high corrosion resistance and can be used for very demanding applications. A new lean duplex steel, LDX 2101 {sup registered} (EN 1.4162, UNS S32101), has been developed with corrosion resistance on a par with standard austenitic grades. Application areas include: structural components, chemical industry, tanks and containers. The steel was designed to have equal amounts of ferrite and austenite in annealed condition and with an austenite that is stable against strain-induced martensite. Thanks to its high nitrogen content, the steel has a fast austenite reformation when subjected to thermal cycling, e.g. welding. Unlike conventional duplex grades, the formation of intermetallic phase is very sluggish, although precipitation of nitrides and carbides has a certain impact on material properties after exposure in the temperature range 600 to 800 C. The precipitation behaviour after different isothermal treatments is described and its influence on different product properties is shown. A good agreement was found between impact toughness and corrosion resistance for a wide range of thermal treatments. (orig.)

The Contribution of the Activation Entropy to the Gas-Phase Stability of Modified Nucleic Acid Duplexes

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Hari, Yvonne; Dugovič, Branislav; Istrate, Alena; Fignolé, Annabel; Leumann, Christian J.; Schürch, Stefan

2016-07-01

Tricyclo-DNA (tcDNA) is a sugar-modified analogue of DNA currently tested for the treatment of Duchenne muscular dystrophy in an antisense approach. Tandem mass spectrometry plays a key role in modern medical diagnostics and has become a widespread technique for the structure elucidation and quantification of antisense oligonucleotides. Herein, mechanistic aspects of the fragmentation of tcDNA are discussed, which lay the basis for reliable sequencing and quantification of the antisense oligonucleotide. Excellent selectivity of tcDNA for complementary RNA is demonstrated in direct competition experiments. Moreover, the kinetic stability and fragmentation pattern of matched and mismatched tcDNA heteroduplexes were investigated and compared with non-modified DNA and RNA duplexes. Although the separation of the constituting strands is the entropy-favored fragmentation pathway of all nucleic acid duplexes, it was found to be only a minor pathway of tcDNA duplexes. The modified hybrid duplexes preferentially undergo neutral base loss and backbone cleavage. This difference is due to the low activation entropy for the strand dissociation of modified duplexes that arises from the conformational constraint of the tc-sugar-moiety. The low activation entropy results in a relatively high free activation enthalpy for the dissociation comparable to the free activation enthalpy of the alternative reaction pathway, the release of a nucleobase. The gas-phase behavior of tcDNA duplexes illustrates the impact of the activation entropy on the fragmentation kinetics and suggests that tandem mass spectrometric experiments are not suited to determine the relative stability of different types of nucleic acid duplexes.

Multilayer checkpoints for microRNA authenticity during RISC assembly.

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Kawamata, Tomoko; Yoda, Mayuko; Tomari, Yukihide

2011-09-01

MicroRNAs (miRNAs) function through the RNA-induced silencing complex (RISC), which contains an Argonaute (Ago) protein at the core. RISC assembly follows a two-step pathway: miRNA/miRNA* duplex loading into Ago, and separation of the two strands within Ago. Here we show that the 5' phosphate of the miRNA strand is essential for duplex loading into Ago, whereas the preferred 5' nucleotide of the miRNA strand and the base-pairing status in the seed region and the middle of the 3' region function as additive anchors to Ago. Consequently, the miRNA authenticity is inspected at multiple steps during RISC assembly.

Hybridization Properties of RNA Containing 8-Methoxyguanosine and 8-Benzyloxyguanosine.

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Daniel Sylwester Baranowski

Full Text Available Modified nucleobase analogues can serve as powerful tools for changing physicochemical and biological properties of DNA or RNA. Guanosine derivatives containing bulky substituents at 8 position are known to adopt syn conformation of N-glycoside bond. On the contrary, in RNA the anti conformation is predominant in Watson-Crick base pairing. In this paper two 8-substituted guanosine derivatives, 8-methoxyguanosine and 8-benzyloxyguanosine, were synthesized and incorporated into oligoribonucleotides to investigate their influence on the thermodynamic stability of RNA duplexes. The methoxy and benzyloxy substituents are electron-donating groups, decreasing the rate of depurination in the monomers, as confirmed by N-glycoside bond stability assessments. Thermodynamic stability studies indicated that substitution of guanosine by 8-methoxy- or 8-benzyloxyguanosine significantly decreased the thermodynamic stability of RNA duplexes. Moreover, the presence of 8-substituted guanosine derivatives decreased mismatch discrimination. Circular dichroism spectra of modified RNA duplexes exhibited patterns typical for A-RNA geometry.

[A Duplex PCR Method for Detection of Babesia caballi and Theileria equi].

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Zhang, Yang; Zhang, Yu-ting; Wang, Zhen-bao; Bolati; Li, Hai; Bayinchahan

2015-04-01

To develop a duplex PCR assay for detection of Babesia caballi and Theileria equi. Two pairs of primers were designed according to the BC48 gene of B. caballi and 18 s rRNA gene of T. equi, and a duplex PCR assay was developed by the optimization of reaction conditions. The specificity, sensitivity and reliability of the method were tested. The horse blood samples of suspected cases were collected from Yili region, and detected by the duplex PCR, microspopy, conventional PCR, and fluorescence quantitative PCR, and the results were compared. Using the duplex PCR assay, the specific fragments of 155 bp and 280 bp were amplified from DNA samples of B. caballi and T. equi, respectively. No specific fragment was amplified from DNA samples of B. bigemina, Theilerdia annulata, Theilerdia sergenti, Toxoplasma gondii, Neospora caninum, and Trypanosoma evansi. The limit of detection was 4.85 x 10(5) copies/L for B. caballi DNA and 4.85 x 10(4) copies/µl for T. equi DNA, respectively. Among the 24 blood samples, 11 were found B. caballi-positive by the duplex PCR assay, and 18 were T. equi-positive. The coincidence rate of microscopy, conventional PCR, and fluorescence quantitative PCR with duplex PCR was 91.7% (22/24), 95.8% (23/24), and 95.8% (23/24), respectively. A duplex PCR assay for simultaneous detection of B. caballi and T. equi is established.

Molecular detection of infectious bronchitis and Newcastle disease viruses in broiler chickens with respiratory signs using Duplex RT-PCR.

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Saba Shirvan, Aylar; Mardani, Karim

2014-01-01

Infectious bronchitis (IB) and Newcastle disease (ND) are highly contagious and the most economically important diseases of the poultry affecting respiratory tract and causing economic losses in poultry industry throughout the world. In the present study, the simultaneous detection and differentiation of causative agents of these diseases were investigated using duplex-RT-PCR. RNA was extracted from vaccinal and reference strains of infectious bronchitis virus (IBV) and Newcastle disease virus (NDV) and then cDNA was synthesized. Using two universal primer sets for detection of IBV and NDV, the duplex-RT-PCR was developed. In order to assess the efficiency of the developed duplex RT-PCR, a number of 12 broiler farms with the symptoms of respiratory tract infection was sampled (trachea, lung and kidney were sampled from affected birds suspicious for IBV and NDV infections). After RNA extraction from tissues and cDNA synthesis, the presence of IBV and NDV genome were investigated using duplex-PCR. The results showed that three of twelve examined broiler farms were positive for IBV and two farms were positive for NDV and IBV. The results revealed that the duplex-RT-PCR is a quick and sensitive procedure for simultaneously detecting IBV and NDV in birds with respiratory infections.

Motif III in superfamily 2 "helicases" helps convert the binding energy of ATP into a high-affinity RNA binding site in the yeast DEAD-box protein Ded1.

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Banroques, Josette; Doère, Monique; Dreyfus, Marc; Linder, Patrick; Tanner, N Kyle

2010-03-05

Motif III in the putative helicases of superfamily 2 is highly conserved in both its sequence and its structural context. It typically consists of the sequence alcohol-alanine-alcohol (S/T-A-S/T). Historically, it was thought to link ATPase activity with a "helicase" strand displacement activity that disrupts RNA or DNA duplexes. DEAD-box proteins constitute the largest family of superfamily 2; they are RNA-dependent ATPases and ATP-dependent RNA binding proteins that, in some cases, are able to disrupt short RNA duplexes. We made mutations of motif III (S-A-T) in the yeast DEAD-box protein Ded1 and analyzed in vivo phenotypes and in vitro properties. Moreover, we made a tertiary model of Ded1 based on the solved structure of Vasa. We used Ded1 because it has relatively high ATPase and RNA binding activities; it is able to displace moderately stable duplexes at a large excess of substrate. We find that the alanine and the threonine in the second and third positions of motif III are more important than the serine, but that mutations of all three residues have strong phenotypes. We purified the wild-type and various mutants expressed in Escherichia coli. We found that motif III mutations affect the RNA-dependent hydrolysis of ATP (k(cat)), but not the affinity for ATP (K(m)). Moreover, mutations alter and reduce the affinity for single-stranded RNA and subsequently reduce the ability to disrupt duplexes. We obtained intragenic suppressors of the S-A-C mutant that compensate for the mutation by enhancing the affinity for ATP and RNA. We conclude that motif III and the binding energy of gamma-PO(4) of ATP are used to coordinate motifs I, II, and VI and the two RecA-like domains to create a high-affinity single-stranded RNA binding site. It also may help activate the beta,gamma-phosphoanhydride bond of ATP. (c) 2009 Elsevier Ltd. All rights reserved.

Development of dansyl-modified oligonucleotide probes responding to structural changes in a duplex.

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Suzuki, Yoshio; Kowata, Keiko; Komatsu, Yasuo

2013-11-15

We have synthesized a nonnucleoside amidite block of dansyl fluorophore to prepare dansyl-modified oligonucleotides (ONTs). The fluorescence intensities of dansyl-ONT specifically increased by the presence of adjacent guanosine residues but, significantly reduced in a dansyl-flipping duplex. These changes were caused by solvatochromism effect due to the number of guanine which is hydrophobic functional group and the external environment of dansyl group. The fluorescence intensities could be plotted as a function of the ONTs concentrations and the increase in the fluorescence was observed to equimolar concentrations of target DNA. This duplex exhibited higher melting temperature relative to the corresponding duplexes containing other base pairs. Similar changes in fluorescence could be detected upon hybridization with complementary RNAs. Thus, the dansyl-modified ONTs provide sequence specific fluorescent probe of DNA and RNA. Copyright © 2013 Elsevier Ltd. All rights reserved.

Genetic mapping uncovers cis-regulatory landscape of RNA editing.

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Ramaswami, Gokul; Deng, Patricia; Zhang, Rui; Anna Carbone, Mary; Mackay, Trudy F C; Li, Jin Billy

2015-09-16

Adenosine-to-inosine (A-to-I) RNA editing, catalysed by ADAR enzymes conserved in metazoans, plays an important role in neurological functions. Although the fine-tuning mechanism provided by A-to-I RNA editing is important, the underlying rules governing ADAR substrate recognition are not well understood. We apply a quantitative trait loci (QTL) mapping approach to identify genetic variants associated with variability in RNA editing. With very accurate measurement of RNA editing levels at 789 sites in 131 Drosophila melanogaster strains, here we identify 545 editing QTLs (edQTLs) associated with differences in RNA editing. We demonstrate that many edQTLs can act through changes in the local secondary structure for edited dsRNAs. Furthermore, we find that edQTLs located outside of the edited dsRNA duplex are enriched in secondary structure, suggesting that distal dsRNA structure beyond the editing site duplex affects RNA editing efficiency. Our work will facilitate the understanding of the cis-regulatory code of RNA editing.

Cy3 and Cy5 dyes attached to oligonucleotide terminus stabilize DNA duplexes: predictive thermodynamic model.

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Moreira, Bernardo G; You, Yong; Owczarzy, Richard

2015-03-01

Cyanine dyes are important chemical modifications of oligonucleotides exhibiting intensive and stable fluorescence at visible light wavelengths. When Cy3 or Cy5 dye is attached to 5' end of a DNA duplex, the dye stacks on the terminal base pair and stabilizes the duplex. Using optical melting experiments, we have determined thermodynamic parameters that can predict the effects of the dyes on duplex stability quantitatively (ΔG°, Tm). Both Cy dyes enhance duplex formation by 1.2 kcal/mol on average, however, this Gibbs energy contribution is sequence-dependent. If the Cy5 is attached to a pyrimidine nucleotide of pyrimidine-purine base pair, the stabilization is larger compared to the attachment to a purine nucleotide. This is likely due to increased stacking interactions of the dye to the purine of the complementary strand. Dangling (unpaired) nucleotides at duplex terminus are also known to enhance duplex stability. Stabilization originated from the Cy dyes is significantly larger than the stabilization due to the presence of dangling nucleotides. If both the dangling base and Cy3 are present, their thermodynamic contributions are approximately additive. New thermodynamic parameters improve predictions of duplex folding, which will help design oligonucleotide sequences for biophysical, biological, engineering, and nanotechnology applications. Copyright © 2015. Published by Elsevier B.V.

Vesicoureteral Reflux and Duplex Systems

OpenAIRE

Thomas, John C.

2008-01-01

Vesicoureteral reflux (VUR) is the most common anomaly associated with duplex systems. In addition to an uncomplicated duplex system, reflux can also be secondary in the presence of an ectopic ureterocele with duplex systems. Controversy exists in regard to the initial and most definitive management of these anomalies when they coexist. This paper will highlight what is currently known about duplex systems and VUR, and will attempt to provide evidence supporting the various surgical approa...

Influence of nucleotide modifications at the C2' position on the Hoogsteen base-paired parallel-stranded duplex of poly(A) RNA.

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Copp, William; Denisov, Alexey Y; Xie, Jingwei; Noronha, Anne M; Liczner, Christopher; Safaee, Nozhat; Wilds, Christopher J; Gehring, Kalle

2017-09-29

Polyadenylate (poly(A)) has the ability to form a parallel duplex with Hoogsteen adenine:adenine base pairs at low pH or in the presence of ammonium ions. In order to evaluate the potential of this structural motif for nucleic acid-based nanodevices, we characterized the effects on duplex stability of substitutions of the ribose sugar with 2'-deoxyribose, 2'-O-methyl-ribose, 2'-deoxy-2'-fluoro-ribose, arabinose and 2'-deoxy-2'-fluoro-arabinose. Deoxyribose substitutions destabilized the poly(A) duplex both at low pH and in the presence of ammonium ions: no duplex formation could be detected with poly(A) DNA oligomers. Other sugar C2' modifications gave a variety of effects. Arabinose and 2'-deoxy-2'-fluoro-arabinose nucleotides strongly destabilized poly(A) duplex formation. In contrast, 2'-O-methyl and 2'-deoxy-2'-fluoro-ribo modifications were stabilizing either at pH 4 or in the presence of ammonium ions. The differential effect suggests they could be used to design molecules selectively responsive to pH or ammonium ions. To understand the destabilization by deoxyribose, we determined the structures of poly(A) duplexes with a single DNA residue by nuclear magnetic resonance spectroscopy and X-ray crystallography. The structures revealed minor structural perturbations suggesting that the combination of sugar pucker propensity, hydrogen bonding, pKa shifts and changes in hydration determine duplex stability. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Establishment and Evaluation of Stable Cell Lines Inhibiting Foot-and-Mouth Disease Virus by RNA Interference

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Yuan-xing Gu

2014-01-01

Full Text Available RNA interference (RNAi has been proved to be a powerful tool for foot-and-mouth disease virus FMDV inhibition in vitro and in vivo. We established five stable baby hamster kidney 21 cell lines (BHK-21 containing five short hairpin RNAs (shRNAs expression plasmids (p3D1shRNA, p3D2shRNA, p3D3shRNA, p3D4shRNA, and p3D5shRNA targeting 3D gene of FMDV. Immunofluorescent assay, virus titration, and real-time quantitative reverse transcription polymerase chain reaction (Q-RT-PCR were conducted to detect the effect of shRNAs on FMDV replication. After challenged with FMDV of O/CHA/99, two cell lines (p3D1shRNA and p3D4shRNA showed a significant reduction in the synthesis of viral protein and RNA, accompanied by a sharp decrease in viral yield, and the inhibition could last for at least thirty passages. We developed an efficient procedure for the establishment and evaluation of stable cell lines for anti-FMDV research based on RNAi technology, which can be a candidate method for anti-FMDV research.

Welding of duplex and super-duplex stainless steels

International Nuclear Information System (INIS)

Van Nassau, L.; Meelker, H.; Hilkes, J.

1994-01-01

After a recall of the commercial designation of duplex or super-duplex steels (22-27% Cr, 4-8% Ni, 0.1-0.3% N with or without Mo (1.5-4%)) and of some metallurgical properties (phase diagrams, microstructure, ferrite determination, heat treatment and aging), welding technologies are synthetically presented (advantages-disadvantages of each process, metals filler, parameters of the welding processes, heat treatments after welding, cleaning, passivation, properties (mechanical, corrosion resistance) of the welded pieces). (A.B.). 28 refs. 5 figs., 15 tabs., 1 annexe

Backbone conformation affects duplex initiation and duplex propagation in hybridisation of synthetic H-bonding oligomers.

Science.gov (United States)

Iadevaia, Giulia; Núñez-Villanueva, Diego; Stross, Alexander E; Hunter, Christopher A

2018-06-06

Synthetic oligomers equipped with complementary H-bond donor and acceptor side chains form multiply H-bonded duplexes in organic solvents. Comparison of the duplex forming properties of four families of oligomers with different backbones shows that formation of an extended duplex with three or four inter-strand H-bonds is more challenging than formation of complexes that make only two H-bonds. The stabilities of 1 : 1 complexes formed between length complementary homo-oligomers equipped with either phosphine oxide or phenol recognition modules were measured in toluene. When the backbone is very flexible (pentane-1,5-diyl thioether), the stability increases uniformly by an order of magnitude for each additional base-pair added to the duplex: the effective molarities for formation of the first intramolecular H-bond (duplex initiation) and subsequent intramolecular H-bonds (duplex propagation) are similar. This flexible system is compared with three more rigid backbones that are isomeric combinations of an aromatic ring and methylene groups. One of the rigid systems behaves in exactly the same way as the flexible backbone, but the other two do not. For these systems, the effective molarity for formation of the first intramolecular H-bond is the same as that found for the other two backbones, but additional H-bonds are not formed between the longer oligomers. The effective molarities are too low for duplex propagation in these systems, because the oligomer backbones cannot adopt conformations compatible with formation of an extended duplex.

Full Duplex Emulation via Spatial Separation of Half Duplex Nodes in a Planar Cellular Network

DEFF Research Database (Denmark)

Thomsen, Henning; Kim, Dong Min; Popovski, Petar

2016-01-01

A Full Duplex Base Station (FD-BS) can be used to serve simultaneously two Half-Duplex (HD) Mobile Stations (MSs), one working in the uplink and one in the downlink, respectively. The same functionality can be realized by having two interconnected and spatially separated Half Duplex Base Stations...... (HD-BSs), which is a scheme termed CoMPflex (CoMP for In-Band Wireless Full Duplex). A FD-BS can be seen as a special case of CoMPflex with separation distance zero. In this paper we study the performance of CoMPflex in a two-dimensional cellular scenario using stochastic geometry and compare...

Synthesis and Structural Characterization of 2'-Fluoro-α-L-RNA-Modified Oligonucleotides

DEFF Research Database (Denmark)

Bundgaard Jensen, Troels; Pasternak, Anna; Stahl Madsen, Andreas

2011-01-01

with the smallest destabilization towards RNA. Thermodynamic data show that the duplex formation with 2'-fluoro-α-L-RNA nucleotides is enthalpically disfavored but entropically favored. 2'-Fluoro-α-L-RNA nucleotides exhibit very good base pairing specificity following Watson-Crick rules. The 2'-fluoro......-α-L-RNA monomer was designed as a monocyclic mimic of the bicyclic α-L-LNA, and molecular modeling showed that this indeed is the case as the 2'-fluoro monomer adopts a C3'-endo/C2'-exo sugar pucker. Molecular modeling of modified duplexes show that the 2'-fluoro-α-L-RNA nucleotides partake in Watson-Crick base......We describe the synthesis and binding properties of oligonucleotides that contain one or more 2'-fluoro-α-L-RNA thymine monomer(s). Incorporation of 2'-fluoro-α-L-RNA thymine into oligodeoxynucleotides decreased thermal binding stability slightly upon hybridization with complementary DNA and RNA...

Structural studies of the 5'-phenazinium-tethered matched and G-A-mismatched DNA duplexes by NMR spectroscopy.

Science.gov (United States)

Maltseva, T; Sandström, A; Ivanova, I M; Sergeyev, D S; Zarytova, V F; Chattopadhyaya, J

1993-05-01

The mechanism through which modified oligo-DNA analogues act as antisense repressors at the transcriptional and translational level of gene expression is based on the information content in the nucleotide sequence which is determined by the specific base pairing. The efficiency of such action is largely determined by the stability of the duplex formed between the oligonucleotide reagent and the target sequence and also by the mismatched base pairing, such as G-A, that occurs during replication or recombination. We herein report that the phenazinium (Pzn)-tethered matched duplex p(d(TGTTTGGC)):(Pzn)-p(d(CCAAACA)) (III) (Tm = 50 degrees C) has a much larger stability than the parent matched duplex p(d(TGTTTGGC)):p(d(CCAAACA)) (I) (Tm = 30 degrees C). On the other hand, the Pzn-tethered G-A-mismatched duplex p(d(TGTTTGGC)):(Pzn)-p(d(ACAAACA)) (IV) (Tm = 34 degrees C) is only slightly more stable than its parent mismatched duplex p(d(TGTTTGGC)):p(d(ACAAACA)) (Tm = 25 degrees C). A detailed 500 MHz NMR study and constrained MD refinements of NMR-derived structures have been undertaken for the DNA duplexes (I), (II), (III) and (IV) in order to understand the structural basis of stabilization of Pzn-tethered matched DNA duplex (delta Tm = 20 degrees C) compared to mismatched duplex (delta Tm = 9 degrees C). Assignment of the 1H-NMR (500 MHz) spectra of the duplexes has been carried out by 2D NOESY, HOHAHA and DQF-COSY experiments. The torsion angles have been extracted from the J-coupling constants obtained by simulation of most of the DQF-COSY cross-peaks using program SMART. The solution structure of the duplexes were assessed by an iterative hybride relaxation matrix method (MORASS) combined with NOESY distances and torsion angles restrained molecular dynamics (MD) using program Amber 4.0. The standard Amber 4.0 force-field parameters were used for the oligonucleotide in conjunction with the new parameters for Pzn residue which was obtained by full geometry

Harvesting full-duplex rate gains in cellular networks with half-duplex user terminals

KAUST Repository

Alammouri, Ahmad; Elsawy, Hesham; Alouini, Mohamed-Slim

2016-01-01

Full-Duplex (FD) transceivers may be expensive in terms of complexity, power consumption, and price to be implemented in all user terminals. Therefore, techniques to exploit in-band full-duplex communication with FD base stations (BSs) and half

Achieving single channel, full duplex wireless communication

KAUST Repository

Choi, Jung Il; Jain, Mayank; Srinivasan, Kannan; Levis, Phil; Katti, Sachin

2010-01-01

This paper discusses the design of a single channel full-duplex wireless transceiver. The design uses a combination of RF and baseband techniques to achieve full-duplexing with minimal effect on link reliability. Experiments on real nodes show the full-duplex prototype achieves median performance that is within 8% of an ideal full-duplexing system. This paper presents Antenna Cancellation, a novel technique for self-interference cancellation. In conjunction with existing RF interference cancellation and digital baseband interference cancellation, antenna cancellation achieves the amount of self-interference cancellation required for full-duplex operation. The paper also discusses potential MAC and network gains with full-duplexing. It suggests ways in which a full-duplex system can solve some important problems with existing wireless systems including hidden terminals, loss of throughput due to congestion, and large end-to-end delays. Copyright 2010 ACM.

Identification of miRNA targets with stable isotope labeling by amino acids in cell culture

DEFF Research Database (Denmark)

Vinther, Jeppe; Hedegaard, Mads Marquardt; Gardner, Paul Phillip

2006-01-01

miRNAs are small noncoding RNAs that regulate gene expression. We have used stable isotope labeling by amino acids in cell culture (SILAC) to investigate the effect of miRNA-1 on the HeLa cell proteome. Expression of 12 out of 504 investigated proteins was repressed by miRNA-1 transfection...

Low-Temperature Mechanical Behavior of Super Duplex Stainless Steel with Sigma Precipitation

OpenAIRE

Kim, Seul-Kee; Kang, Ki-Yeob; Kim, Myung-Soo; Lee, Jae-Myung

2015-01-01

Experimental studies in various aspects have to be conducted to maintain stable applications of super duplex stainless steels (SDSS) because the occurrence rate of sigma phase, variable temperature and growth direction of sigma phase can influence mechanical performances of SDSS. Tensile tests of precipitated SDSS were performed under various temperatures to analyze mechanical and morphological behavior.

Low-Temperature Mechanical Behavior of Super Duplex Stainless Steel with Sigma Precipitation

Directory of Open Access Journals (Sweden)

Seul-Kee Kim

2015-09-01

Full Text Available Experimental studies in various aspects have to be conducted to maintain stable applications of super duplex stainless steels (SDSS because the occurrence rate of sigma phase, variable temperature and growth direction of sigma phase can influence mechanical performances of SDSS. Tensile tests of precipitated SDSS were performed under various temperatures to analyze mechanical and morphological behavior.

Structural Properties of G,T-Parallel Duplexes

Directory of Open Access Journals (Sweden)

Anna Aviñó

2010-01-01

Full Text Available The structure of G,T-parallel-stranded duplexes of DNA carrying similar amounts of adenine and guanine residues is studied by means of molecular dynamics (MD simulations and UV- and CD spectroscopies. In addition the impact of the substitution of adenine by 8-aminoadenine and guanine by 8-aminoguanine is analyzed. The presence of 8-aminoadenine and 8-aminoguanine stabilizes the parallel duplex structure. Binding of these oligonucleotides to their target polypyrimidine sequences to form the corresponding G,T-parallel triplex was not observed. Instead, when unmodified parallel-stranded duplexes were mixed with their polypyrimidine target, an interstrand Watson-Crick duplex was formed. As predicted by theoretical calculations parallel-stranded duplexes carrying 8-aminopurines did not bind to their target. The preference for the parallel-duplex over the Watson-Crick antiparallel duplex is attributed to the strong stabilization of the parallel duplex produced by the 8-aminopurines. Theoretical studies show that the isomorphism of the triads is crucial for the stability of the parallel triplex.

Development of duplex PCR for simultaneous detection of Theileria spp. and Anaplasma spp. in sheep and goats.

Science.gov (United States)

Cui, Yanyan; Zhang, Yan; Jian, Fuchun; Zhang, Longxian; Wang, Rongjun; Cao, Shuxuan; Wang, Xiaoxing; Yan, Yaqun; Ning, Changshen

2017-05-01

Theileria spp. and Anaplasma spp., which are important tick-borne pathogens (TBPs), impact the health of humans and animals in tropical and subtropical areas. Theileria and Anaplasma co-infections are common in sheep and goats. Following alignment of the relevant DNA sequences, two primer sets were designed to specifically target the Theileria spp. 18S rRNA and Anaplasma spp. 16S rRNA gene sequences. Genomic DNA from the two genera was serially diluted tenfold for testing the sensitivities of detection of the primer sets. The specificities of the primer sets were confirmed when DNA from Anaplasma and Theileria (positive controls), other related hematoparasites (negative controls) and ddH 2 O were used as templates. Fifty field samples were also used to evaluate the utility of single PCR and duplex PCR assays, and the detection results were compared with those of the PCR methods previously published. An optimized duplex PCR assay was established from the two primer sets based on the relevant genes from the two TBPs, and this assay generated products of 298-bp (Theileria spp.) and 139-bp (Anaplasma spp.). The detection limit of the assay was 29.4 × 10 -3  ng per μl, and there was no cross-reaction with the DNA from other hematoparasites. The results showed that the newly developed duplex PCR assay had an efficiency of detection (P > 0.05) similar to other published PCR methods. In this study, a duplex PCR assay was developed that can simultaneously identify Theileria spp. and Anaplasma spp. in sheep and goats. This duplex PCR is a potentially valuable assay for epidemiological studies of TBPs in that it can detect cases of mixed infections of the pathogens. Copyright © 2017 Elsevier Inc. All rights reserved.

Duplex gall bladder: bystander or culprit.

Science.gov (United States)

Kumar, Jogender; Yadav, Arushi

2017-08-30

Gall bladder (GB) duplication is a rare anatomical malformation, which can be detected by preoperative imaging study. We present a case of duplex gall bladder in a 14-year-old boy who presented with abdominal pain. On ultrasound, he had right nephrolithiasis and duplex gall bladder. Duplex gall bladder was confirmed on MR cholangiopancreatography. There was a dilemma for surgical management of duplex gall bladder; however, he became asymptomatic after conservative treatment. Prophylactic surgery is not recommended for asymptomatic incidentally detected duplex gall bladder. Radiologists and paediatric surgeons should be sensitised about the exact anatomy of this entity. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Molecular dynamics analysis of stabilities of the telomeric Watson-Crick duplex and the associated i-motif as a function of pH and temperature.

Science.gov (United States)

Panczyk, Tomasz; Wolski, Pawel

2018-06-01

This work deals with a molecular dynamics analysis of the protonated and deprotonated states of the natural sequence d[(CCCTAA) 3 CCCT] of the telomeric DNA forming the intercalated i-motif or paired with the sequence d[(CCCTAA) 3 CCCT] and forming the Watson-Crick (WC) duplex. By utilizing the amber force field for nucleic acids we built the i-motif and the WC duplex either with native cytosines or using their protonated forms. We studied, by applying molecular dynamics simulations, the role of hydrogen bonds between cytosines or in cytosine-guanine pairs in the stabilization of both structures in the physiological fluid. We found that hydrogen bonds exist in the case of protonated i-motif and in the standard form of the WC duplex. They, however, vanish in the case of the deprotonated i-motif and protonated form of the WC duplex. By determining potentials of mean force in the enforced unwrapping of these structures we found that the protonated i-motif is thermodynamically the most stable. Its deprotonation leads to spontaneous and observed directly in the unbiased calculations unfolding of the i-motif to the hairpin structure at normal temperature. The WC duplex is stable in its standard form and its slight destabilization is observed at the acidic pH. However, the protonated WC duplex unwraps very slowly at 310 K and its decomposition was not observed in the unbiased calculations. At higher temperatures (ca. 400 K or more) the WC duplex unwraps spontaneously. Copyright © 2018. Published by Elsevier B.V.

Expanding the action of duplex RNAs into the nucleus: redirecting alternative splicing

Science.gov (United States)

Liu, Jing; Hu, Jiaxin; Corey, David R.

2012-01-01

Double-stranded RNAs are powerful agents for silencing gene expression in the cytoplasm of mammalian cells. The potential for duplex RNAs to control expression in the nucleus has received less attention. Here, we investigate the ability of small RNAs to redirect splicing. We identify RNAs targeting an aberrant splice site that restore splicing and production of functional protein. RNAs can target sequences within exons or introns and affect the inclusion of exons within SMN2 and dystrophin, genes responsible for spinal muscular atrophy and Duchenne muscular dystrophy, respectively. Duplex RNAs recruit argonaute 2 (AGO2) to pre-mRNA transcripts and altered splicing requires AGO2 expression. AGO2 promotes transcript cleavage in the cytoplasm, but recruitment of AGO2 to pre-mRNAs does not reduce transcript levels, exposing a difference between cytoplasmic and nuclear pathways. Involvement of AGO2 in splicing, a classical nuclear process, reinforces the conclusion from studies of RNA-mediated transcriptional silencing that RNAi pathways can be adapted to function in the mammalian nucleus. These data provide a new strategy for controlling splicing and expand the reach of small RNAs within the nucleus of mammalian cells. PMID:21948593

Raman study of magnesium induced conversion of polyU·polyA duplexes to polyU·polyA·polyU triplexes

OpenAIRE

Herrera, S. J. Espinoza; Štepánek, J.

2010-01-01

Raman titration experiment with magnesium salt added gradually to aqueous solution of duplexes formed by RNA homopolynucleotides polyU and polyA was performed to reveal its effect on homopolynucleotide complexes. Statistical analysis of obtained spectral set has confirmed the effect already found by less structurally sensitive methods [Nucleic Acids Res. 31(17) (2003), 5101–5107] that at sufficiently high concentrations magnesium causes transformation of polyU·polyA duplexes to polyU·polyA·po...

Overall performance of the duplex Stirling refrigerator

International Nuclear Information System (INIS)

Erbay, L. Berrin; Ozturk, M. Mete; Doğan, Bahadır

2017-01-01

Highlights: • Overall performance coefficient of duplex Stirling refrigerator was investigated. • A definite region for the coefficient of performance of the refrigerator in duplex Stirling is identified. • A definite region for the thermal efficiency of the heat engine in duplex Stirling is identified. • Benchmark values and design bounds of the duplex Stirling refrigerator were obtained. - Abstract: The duplex Stirling refrigerator is an integrated refrigerator consists of Stirling cycle engine and Stirling cycle refrigerator used for cooling. The equality of the work generation of the heat engine to the work consumption of the refrigerator is the primary constraint of the duplex Stirling. The duplex Stirling refrigerator is investigated thermodynamically by considering the effects of constructional and operational parameters which are namely the temperature ratios for heat engine and refrigerator, and the compression ratios for both sides. The primary concern is given to the parametric effects on the overall coefficient of performance of the duplex Stirling refrigerator. The given diagrams provide a design bounds and benchmark results that allows seeing the big picture about the cooling load and heat input relation. Moreover they ease to determine the corresponding work rate to the target cooling load. As regard to the obtained results, a definite region for coefficient of performance of the refrigerator and a definite region for the thermal efficiency of the heat engine of the duplex Stirling are identified.

TAPIR, a web server for the prediction of plant microRNA targets, including target mimics.

Science.gov (United States)

Bonnet, Eric; He, Ying; Billiau, Kenny; Van de Peer, Yves

2010-06-15

We present a new web server called TAPIR, designed for the prediction of plant microRNA targets. The server offers the possibility to search for plant miRNA targets using a fast and a precise algorithm. The precise option is much slower but guarantees to find less perfectly paired miRNA-target duplexes. Furthermore, the precise option allows the prediction of target mimics, which are characterized by a miRNA-target duplex having a large loop, making them undetectable by traditional tools. The TAPIR web server can be accessed at: http://bioinformatics.psb.ugent.be/webtools/tapir. Supplementary data are available at Bioinformatics online.

Buffer management in wireless full-duplex systems

KAUST Repository

Bouacida, Nader

2015-10-19

Wireless full-duplex radios can simultaneously transmit and receive using the same frequency. In theory, this can double the throughput. In fact, there is only little work addressing aspects other than throughput gains in full-duplex systems. Over-buffering in today\\'s networks or the so-called “bufferbloat” phenomenon creates excessive end-to-end delays resulting in network performance degradation. Our analysis shows that full-duplex systems may suffer from high latency caused by bloated buffers. In this paper, we address the problem of buffer management in full-duplex networks by using Wireless Queue Management (WQM), which is an active queue management technique for wireless networks. Our solution is based on Relay Full-Duplex MAC (RFD-MAC), an asynchronous media access control protocol designed for relay full-duplexing. We compare the performance of WQM in full-duplex environment to Drop Tail mechanism over various scenarios. Our solution reduces the end-to-end delay by two orders of magnitude while achieving similar throughput in most of the cases.

Practical, real-time, full duplex wireless

KAUST Repository

Jain, Mayank; Choi, Jung Il; Kim, Taemin; Bharadia, Dinesh; Seth, Siddharth; Srinivasan, Kannan; Levis, Philip; Katti, Sachin; Sinha, Prasun

2011-01-01

This paper presents a full duplex radio design using signal inversion and adaptive cancellation. Signal inversion uses a simple design based on a balanced/unbalanced (Balun) transformer. This new design, unlike prior work, supports wideband and high power systems. In theory, this new design has no limitation on bandwidth or power. In practice, we find that the signal inversion technique alone can cancel at least 45dB across a 40MHz bandwidth. Further, combining signal inversion cancellation with cancellation in the digital domain can reduce self-interference by up to 73dB for a 10MHz OFDM signal. This paper also presents a full duplex medium access control (MAC) design and evaluates it using a testbed of 5 prototype full duplex nodes. Full duplex reduces packet losses due to hidden terminals by up to 88%. Full duplex also mitigates unfair channel allocation in AP-based networks, increasing fairness from 0.85 to 0.98 while improving downlink throughput by 110% and uplink throughput by 15%. These experimental results show that a re- design of the wireless network stack to exploit full duplex capability can result in significant improvements in network performance. © 2011 ACM.

Structural Insights into the Quadruplex-Duplex 3' Interface Formed from a Telomeric Repeat: A Potential Molecular Target.

Science.gov (United States)

Russo Krauss, Irene; Ramaswamy, Sneha; Neidle, Stephen; Haider, Shozeb; Parkinson, Gary N

2016-02-03

We report here on an X-ray crystallographic and molecular modeling investigation into the complex 3' interface formed between putative parallel stranded G-quadruplexes and a duplex DNA sequence constructed from the human telomeric repeat sequence TTAGGG. Our crystallographic approach provides a detailed snapshot of a telomeric 3' quadruplex-duplex junction: a junction that appears to have the potential to form a unique molecular target for small molecule binding and interference with telomere-related functions. This unique target is particularly relevant as current high-affinity compounds that bind putative G-quadruplex forming sequences only rarely have a high degree of selectivity for a particular quadruplex. Here DNA junctions were assembled using different putative quadruplex-forming scaffolds linked at the 3' end to a telomeric duplex sequence and annealed to a complementary strand. We successfully generated a series of G-quadruplex-duplex containing crystals, both alone and in the presence of ligands. The structures demonstrate the formation of a parallel folded G-quadruplex and a B-form duplex DNA stacked coaxially. Most strikingly, structural data reveals the consistent formation of a TAT triad platform between the two motifs. This triad allows for a continuous stack of bases to link the quadruplex motif with the duplex region. For these crystal structures formed in the absence of ligands, the TAT triad interface occludes ligand binding at the 3' quadruplex-duplex interface, in agreement with in silico docking predictions. However, with the rearrangement of a single nucleotide, a stable pocket can be produced, thus providing an opportunity for the binding of selective molecules at the interface.

Rietveld and impedance analysis of cold and hot rolled duplex and lean duplex steels for application in paper and pulp industry

Energy Technology Data Exchange (ETDEWEB)

Esteves, Luiza; Lins, Vanessa de Freitas Cunha, E-mail: luizaeq@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Quimica; Paiva, Paulo Renato Perdigao [Centro Federal de Educacao Tecnologica de Minas Gerais (CEFET), Belo Horizonte, MG (Brazil); Viana, Adolfo Kalergis do Nascimento [APERAM South America, Timoteo, MG (Brazil)

2017-01-15

In this study, X-Ray Diffraction (XRD) and Rietveld Refinement were performed to identify and quantify the ferrite and austenite phase of cold and hot rolled duplex stainless steels (UNS S31803) and lean duplex stainless steels (UNS S32304). Electrochemical impedance spectroscopy (EIS) was applied to evaluate the chemical behavior of duplex and lean duplex stainless steels in white, green, and black liquors of paper and pulp industry. Rietveld analysis results showed a higher austenite content than the standard limit for duplex steels in the hot rolled condition. The hot rolling condition plays a major role in improving corrosion resistance in white liquor mainly for the lean duplex steel. (author)

Rietveld and impedance analysis of cold and hot rolled duplex and lean duplex steels for application in paper and pulp industry

International Nuclear Information System (INIS)

Esteves, Luiza; Lins, Vanessa de Freitas Cunha; Viana, Adolfo Kalergis do Nascimento

2017-01-01

In this study, X-Ray Diffraction (XRD) and Rietveld Refinement were performed to identify and quantify the ferrite and austenite phase of cold and hot rolled duplex stainless steels (UNS S31803) and lean duplex stainless steels (UNS S32304). Electrochemical impedance spectroscopy (EIS) was applied to evaluate the chemical behavior of duplex and lean duplex stainless steels in white, green, and black liquors of paper and pulp industry. Rietveld analysis results showed a higher austenite content than the standard limit for duplex steels in the hot rolled condition. The hot rolling condition plays a major role in improving corrosion resistance in white liquor mainly for the lean duplex steel. (author)

Development and validation of a duplex real-time PCR assay for the diagnosis of equine piroplasmosis.

Science.gov (United States)

Lobanov, Vladislav A; Peckle, Maristela; Massard, Carlos L; Brad Scandrett, W; Gajadhar, Alvin A

2018-03-02

Equine piroplasmosis (EP) is an economically significant infection of horses and other equine species caused by the tick-borne protozoa Theileria equi and Babesia caballi. The long-term carrier state in infected animals makes importation of such subclinical cases a major risk factor for the introduction of EP into non-enzootic areas. Regulatory testing for EP relies on screening of equines by serological methods. The definitive diagnosis of EP infection in individual animals will benefit from the availability of sensitive direct detection methods, for example, when used as confirmatory assays for non-negative serological test results. The objectives of this study were to develop a real-time quantitative polymerase chain reaction (qPCR) assay for simultaneous detection of both agents of EP, perform comprehensive evaluation of its performance and assess the assay's utility for regulatory testing. We developed a duplex qPCR targeting the ema-1 gene of T. equi and the 18S rRNA gene of B. caballi and demonstrated that the assay has high analytical sensitivities for both piroplasm species. Validation of the duplex qPCR on samples from 362 competitive enzyme-linked immunosorbent assay (cELISA)-negative horses from Canada and the United States yielded no false-positive reactions. The assay's performance was further evaluated using samples collected from 430 horses of unknown EP status from a highly endemic area in Brazil. This set of samples was also tested by a single-target 18S rRNA qPCR for T. equi developed at the OIE reference laboratory for EP in Japan, and a previously published single-target 18S rRNA qPCR for B. caballi whose oligonucleotides we adopted for use in the duplex qPCR. Matching serum samples were tested for antibodies to these parasites using cELISA. By the duplex qPCR, T. equi-specific 18S rRNA qPCR and cELISA, infections with T. equi were detected in 87.9% (95% confidence interval, CI: 84.5-90.7%), 90.5% (95% CI: 87.3-92.3%) and 87.4% (95% CI: 84

Thermal stability of DNA quadruplex-duplex hybrids.

Science.gov (United States)

Lim, Kah Wai; Khong, Zi Jian; Phan, Anh Tuân

2014-01-14

DNA has the capacity to adopt several distinct structural forms, such as duplex and quadruplex helices, which have been implicated in cellular processes and shown to exhibit important functional properties. Quadruplex-duplex hybrids, generated from the juxtaposition of these two structural elements, could find applications in therapeutics and nanotechnology. Here we used NMR and CD spectroscopy to investigate the thermal stability of two classes of quadruplex-duplex hybrids comprising fundamentally distinct modes of duplex and quadruplex connectivity: Construct I involves the coaxial orientation of the duplex and quadruplex helices with continual base stacking across the two components; Construct II involves the orthogonal orientation of the duplex and quadruplex helices with no base stacking between the two components. We have found that for both constructs, the stability of the quadruplex generally increases with the length of the stem-loop incorporated, with respect to quadruplexes comprising nonstructured loops of the same length, which showed a continuous drop in stability with increasing loop length. The stability of these complexes, particularly Construct I, can be substantially influenced by the base-pair steps proximal to the quadruplex-duplex junction. Bulges at the junction are largely detrimental to the adoption of the desired G-quadruplex topology for Construct I but not for Construct II. These findings should facilitate future design and prediction of quadruplex-duplex hybrids.

Prolonged CT urography in duplex kidney.

Science.gov (United States)

Gong, Honghan; Gao, Lei; Dai, Xi-Jian; Zhou, Fuqing; Zhang, Ning; Zeng, Xianjun; Jiang, Jian; He, Laichang

2016-05-13

Duplex kidney is a common anomaly that is frequently associated with multiple complications. Typical computed tomography urography (CTU) includes four phases (unenhanced, arterial, parenchymal and excretory) and has been suggested to considerably aid in the duplex kidney diagnosi. Unfortunately, regarding duplex kidney with prolonged dilatation, the affected parenchyma and tortuous ureters demonstrate a lack of or delayed excretory opacification. We used prolonged-delay CTU, which consists of another prolonged-delay phase (1- to 72-h delay; mean delay: 24 h) to opacify the duplicated ureters and affected parenchyma. Seventeen patients (9 males and 8 females; age range: 2.5-56 y; mean age: 40.4 y) with duplex kidney were included in this study. Unenhanced scans did not find typical characteristics of duplex kidney, except for irregular perirenal morphology. Duplex kidney could not be confirmed on typical four-phase CTU, whereas it could be easily diagnosed in axial and CT-3D reconstruction using prolonged CTU (prolonged-delay phase). Between January 2005 and October 2010, in this review board-approved study (with waived informed consent), 17 patients (9 males and 8 females; age range: 2.5 ~ 56 y; mean age: 40.4 y) with suspicious duplex kidney underwent prolonged CTU to opacify the duplicated ureters and confirm the diagnosis. Our results suggest the validity of prolonged CTU to aid in the evaluation of the function of the affected parenchyma and in the demonstration of urinary tract malformations.

Zoster duplex: a clinical report and etiologic analysis.

Science.gov (United States)

Zhang, Feng; Zhou, Jin

2015-01-01

Herpes zoster (HZ) duplex is a rare disease presentation. The mechanisms of varicella zoster virus (VZV) reactivation in multiple dermal regions are unknown. To present a HZ duplex case occurring in an immunocompetent woman and to analyze the possible underlying causes of HZ duplex. We present a HZ duplex case in an immunocompetent woman and analyzed the possible contributing factors in 36 HZ duplex cases. Continuously distributed variables were categorized by numbers and percentages. In our study, 24 cases (66.7%) were from Asia, 16 cases (44.4%) were in individuals ≥ 50 years of age, and 17 cases (47.2%) occurred in immunocompromised patients. Of the 36 cases, 23 involved women (63.9%) and 13 involved men. Eighteen patients suffering from HZ duplex, 13 of which were women (72.2%), did not suffer from any chronic systemic disease or have a long history of taking drugs. HZ duplex is a rare event that can occur in both immunocompetent and immunosuppressed individuals. HZ duplex might be associated with the Asia region, advanced age, immunosuppression, and being female.

Interference Management in Full-Duplex Cellular Networks with Partial Spectrum Overlap

KAUST Repository

Randrianantenaina, Itsikiantsoa

2017-03-31

Full-duplex (FD) communication is promoted to double the spectral efficiency when compared to the halfduplex (HD) counterpart. In the context of cellular networks, however, FD communication exacerbates the aggregate uplink and downlink interference, which diminishes the foreseen FD gains. This paper considers a flexible duplex system, denoted by -duplex (-D) system, wherein a fine-grained bandwidth control for each uplink/downlink channel pair in each base station (BS) is allowed, which also leads to partial spectrum overlap between the uplink and downlink channels. The paper addresses the resulting interference management problem by maximizing a network-wide rate-based utility function subject to uplink/downlink power constraints, so as to determine userto- BS association, user-to-channel scheduling, the UL and DL transmit powers, and the fraction of spectrum overlap between UL and DL for every user, under the assumption that the number of available channels and users are equal. The paper solves such a non-convex mixed-integer optimization problem in an iterative way by decoupling the problem into several subproblems. Particularly, the user-to-BS association problem is solved using a matching algorithm that is a generalization of the stable marriage problem. The scheduling problem is solved by iterative Hungarian algorithm. The power and spectrum overlap problem is solved by successive convex approximation. The proposed iterative strategy guarantees an efficient one-toone user to BS and channel assignment. It further provides optimized flexible duplexing and power allocation schemes for all transceivers. Simulations results show appreciable gains when comparing the proposed solution to different schemes from the literature.

Interference Management in Full-Duplex Cellular Networks with Partial Spectrum Overlap

KAUST Repository

Randrianantenaina, Itsikiantsoa; Dahrouj, Hayssam; Elsawy, Hesham; Alouini, Mohamed-Slim

2017-01-01

Full-duplex (FD) communication is promoted to double the spectral efficiency when compared to the halfduplex (HD) counterpart. In the context of cellular networks, however, FD communication exacerbates the aggregate uplink and downlink interference, which diminishes the foreseen FD gains. This paper considers a flexible duplex system, denoted by -duplex (-D) system, wherein a fine-grained bandwidth control for each uplink/downlink channel pair in each base station (BS) is allowed, which also leads to partial spectrum overlap between the uplink and downlink channels. The paper addresses the resulting interference management problem by maximizing a network-wide rate-based utility function subject to uplink/downlink power constraints, so as to determine userto- BS association, user-to-channel scheduling, the UL and DL transmit powers, and the fraction of spectrum overlap between UL and DL for every user, under the assumption that the number of available channels and users are equal. The paper solves such a non-convex mixed-integer optimization problem in an iterative way by decoupling the problem into several subproblems. Particularly, the user-to-BS association problem is solved using a matching algorithm that is a generalization of the stable marriage problem. The scheduling problem is solved by iterative Hungarian algorithm. The power and spectrum overlap problem is solved by successive convex approximation. The proposed iterative strategy guarantees an efficient one-toone user to BS and channel assignment. It further provides optimized flexible duplexing and power allocation schemes for all transceivers. Simulations results show appreciable gains when comparing the proposed solution to different schemes from the literature.

Maximizing synchronizability of duplex networks

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Wei, Xiang; Emenheiser, Jeffrey; Wu, Xiaoqun; Lu, Jun-an; D'Souza, Raissa M.

2018-01-01

We study the synchronizability of duplex networks formed by two randomly generated network layers with different patterns of interlayer node connections. According to the master stability function, we use the smallest nonzero eigenvalue and the eigenratio between the largest and the second smallest eigenvalues of supra-Laplacian matrices to characterize synchronizability on various duplexes. We find that the interlayer linking weight and linking fraction have a profound impact on synchronizability of duplex networks. The increasingly large inter-layer coupling weight is found to cause either decreasing or constant synchronizability for different classes of network dynamics. In addition, negative node degree correlation across interlayer links outperforms positive degree correlation when most interlayer links are present. The reverse is true when a few interlayer links are present. The numerical results and understanding based on these representative duplex networks are illustrative and instructive for building insights into maximizing synchronizability of more realistic multiplex networks.

Acute multi-sgRNA knockdown of KEOPS complex genes reproduces the microcephaly phenotype of the stable knockout zebrafish model.

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Tilman Jobst-Schwan

Full Text Available Until recently, morpholino oligonucleotides have been widely employed in zebrafish as an acute and efficient loss-of-function assay. However, off-target effects and reproducibility issues when compared to stable knockout lines have compromised their further use. Here we employed an acute CRISPR/Cas approach using multiple single guide RNAs targeting simultaneously different positions in two exemplar genes (osgep or tprkb to increase the likelihood of generating mutations on both alleles in the injected F0 generation and to achieve a similar effect as morpholinos but with the reproducibility of stable lines. This multi single guide RNA approach resulted in median likelihoods for at least one mutation on each allele of >99% and sgRNA specific insertion/deletion profiles as revealed by deep-sequencing. Immunoblot showed a significant reduction for Osgep and Tprkb proteins. For both genes, the acute multi-sgRNA knockout recapitulated the microcephaly phenotype and reduction in survival that we observed previously in stable knockout lines, though milder in the acute multi-sgRNA knockout. Finally, we quantify the degree of mutagenesis by deep sequencing, and provide a mathematical model to quantitate the chance for a biallelic loss-of-function mutation. Our findings can be generalized to acute and stable CRISPR/Cas targeting for any zebrafish gene of interest.

On phase equilibria in duplex stainless steels

Energy Technology Data Exchange (ETDEWEB)

Wessman, S. [Swerea KIMAB AB, Stockholm (Sweden); Pettersson, R. [Outokumpu Stainless AB, Avesta Research Centre, Avesta (Sweden); Hertzman, S. [Outokumpu Stainless Research Foundation, Stockholm (Sweden)

2010-05-15

The equilibrium conditions of four duplex stainless steels; Fe-23Cr-4.5Ni-0.1N, Fe-22Cr-5.5Ni-3Mo-0.17N, Fe-25Cr-7Ni-4Mo-0.27N and Fe-25Cr-7Ni-4Mo-1W-1.5Cu-0.27N were studied in the temperature region from 700 to 1000 C. Phase compositions were determined with SEM EDS and the phase fractions using image analysis on backscattered SEM images. The results showed that below 1000 C the steels develop an inverse duplex structure with austenite and sigma phase, of which the former is the matrix phase. With decreasing temperature, the microstructure will be more and more complex and finely dispersed. The ferrite is, for the higher alloyed steels, only stable above 1000 C and at lower temperatures disappears in favour of intermetallic phases. The major intermetallic phase is sigma phase with small amounts of chi phase, the latter primarily in high Mo and W grades. Nitrides, not a focus in this investigation, were present as rounded particles and acicular precipitates at lower temperatures. The results were compared to theoretical predictions using the TCFE5 and TCFE6 databases. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

Sequence-specific RNA Photocleavage by Single-stranded DNA in Presence of Riboflavin

Science.gov (United States)

Zhao, Yongyun; Chen, Gangyi; Yuan, Yi; Li, Na; Dong, Juan; Huang, Xin; Cui, Xin; Tang, Zhuo

2015-10-01

Constant efforts have been made to develop new method to realize sequence-specific RNA degradation, which could cause inhibition of the expression of targeted gene. Herein, by using an unmodified short DNA oligonucleotide for sequence recognition and endogenic small molecue, vitamin B2 (riboflavin) as photosensitizer, we report a simple strategy to realize the sequence-specific photocleavage of targeted RNA. The DNA strand is complimentary to the target sequence to form DNA/RNA duplex containing a G•U wobble in the middle. The cleavage reaction goes through oxidative elimination mechanism at the nucleoside downstream of U of the G•U wobble in duplex to obtain unnatural RNA terminal, and the whole process is under tight control by using light as switch, which means the cleavage could be carried out according to specific spatial and temporal requirements. The biocompatibility of this method makes the DNA strand in combination with riboflavin a promising molecular tool for RNA manipulation.

On the Secrecy Degrees of Freedom with Full-Duplex Communication

DEFF Research Database (Denmark)

Mahmood, Nurul Huda; Mogensen, Preben Elgaard

2017-01-01

of such an application. The potential of full duplex nodes in improving the physical layer security of a communication link is investigated in this contribution. We specifically derive the information theoretic secrecy degrees of freedom measure for a pair of nodes communicating in full duplex mode. Moreover, closed...... and the delay reduction of full duplex communication are somewhat limited in realistic network settings, leading researchers to study other possible applications of full duplex communication which can provide significantly higher gains over half duplex communication. Physical layer security is an example...... form expressions for the instantaneous and ergodic throughput gain of full duplex communication over conventional half duplex is derived. The secrecy degrees of freedom with full duplex is shown to be two as opposed to that of zero in half duplex mode....

A distant cis acting intronic element induces site-selective RNA editing

DEFF Research Database (Denmark)

Daniel, Chammiran; Venø, Morten Trillingsgaard; Ekdahl, Ylva

2012-01-01

Transcripts have been found to be site selectively edited from adenosine-to-inosine (A-to-I) in the mammalian brain, mostly in genes involved in neurotransmission. While A-to-I editing occurs at double-stranded structures, other structural requirements are largely unknown. We have investigated...... shown to be important for A-to-I editing. We demonstrate that the element also can induce editing in related but normally not edited RNA sequences. In human, thousands of genes are edited in duplexes formed by inverted repeats in non-coding regions. It is likely that numerous such duplexes can induce...... the requirements for editing at the I/M site in the Gabra-3 transcript of the GABA(A) receptor. We identify an evolutionarily conserved intronic duplex, 150 nt downstream of the exonic hairpin where the I/M site resides, which is required for its editing. This is the first time a distant RNA structure has been...

Full-Duplex Relay Selection in Cognitive Underlay Networks

KAUST Repository

Khafagy, Mohammad Galal; Alouini, Mohamed-Slim; Aissa, Sonia

2017-01-01

In this work, we analyze the performance of full-duplex relay selection (FDRS) in spectrum-sharing networks. Contrary to half-duplex relaying, full-duplex relaying (FDR) enables simultaneous listening/forwarding at the secondary relay(s), thereby

Single-cell duplex RT-LATE-PCR reveals Oct4 and Xist RNA gradients in 8-cell embryos

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Hartung Odelya

2007-12-01

Full Text Available Abstract Background The formation of two distinctive cell lineages in preimplantation mouse embryos is characterized by differential gene expression. The cells of the inner cell mass are pluripotent and express high levels of Oct4 mRNA, which is down-regulated in the surrounding trophectoderm. In contrast, the trophectoderm of female embryos contains Xist mRNA, which is absent from cells of the inner mass. Prior to blastocyst formation, all blastomeres of female embryos still express both of these RNAs. We, thus, postulated that simultaneous quantification of Oct4 and Xist transcripts in individual blastomeres at the 8-cell stage could be informative as to their subsequent fate. Testing this hypothesis, however, presented numerous technical challenges. We overcame these difficulties by combining PurAmp, a single-tube method for RNA preparation and quantification, with LATE-PCR, an advanced form of asymmetric PCR. Results We constructed a duplex RT-LATE-PCR assay for real-time measurement of Oct4 and Xist templates and confirmed its specificity and quantitative accuracy with different methods. We then undertook analysis of sets of blastomeres isolated from embryos at the 8-cell stage. At this stage, all cells in the embryo are still pluripotent and morphologically equivalent. Our results demonstrate, however, that both Oct4 and Xist RNA levels vary in individual blastomeres comprising the same embryo, with some cells having particularly elevated levels of either transcript. Analysis of multiple embryos also shows that Xist and Oct4 expression levels are not correlated at the 8-cell stage, although transcription of both genes is up-regulated at this time in development. In addition, comparison of data from males and females allowed us to determine that the efficiency of the Oct4/Xist assay is unaffected by sex-related differences in gene expression. Conclusion This paper describes the first example of multiplex RT-LATE-PCR and its utility, when

Detecting deletions, insertions, and single nucleotide substitutions in cloned β-globin genes and new polymorphic nucleotide substitutions in β-globin genes in a Japanese population using ribonuclease cleavage at mismatches in RNA: DNA duplexes

International Nuclear Information System (INIS)

Hiyama, Keiko; Kodaira, Mieko; Satoh, Chiyoko.

1990-08-01

The applicability of ribonuclease (RNase) cleavage at mismatches in RNA:DNA duplexes (the RNase cleavage method) for determining nucleotide variant rates was examined in a Japanese population. DNA segments of various lengths obtained from four different regions of one normal and three thalassemic cloned human β-globin genes were inserted into transcription vectors. Sense and antisense RNA probes uniformly labeled with 32 P were prepared. When RNA probes of 771 nucleotides (nt) or less were hybridized with cloned DNAs and the resulting duplexes were treated with a mixture of RNases A and T1, the length of products agreed with theoretical values. Twelve possible mismatches were examined. Since both sense and antisense probes were used, uncleavable mismatches such as G:T and G:G which were made from one combination of RNA and DNA strands could be converted to the cleavable C:A and C:C mismatches, respectively, by using the opposite combination. Deletions and insertions of one (G), four(TTCT), five (ATTTT), and 10 (ATTTTATTTT) nt were easily detected. A polymorphic substitution of T to C at position 666 of the second intervening sequence (IVS2-666) of the β-globin gene was detected using genomic DNAs from cell lines established from the peripheral B lymphocytes of 59 unrelated Japanese from Hiroshima or those amplified by polymerase chain reaction (PCR). The frequency of the gene with C at the IVS2-666 (allele C) was 0.48 and that of the gene with T (allene T) was 0.52. Two new polymorphic substitutions of C to A and A to T were detected at nucleotide positions 1789 and 1945 from the capping site, respectively, using genomic DNAs amplified by PCR. We conclude that it would be feasible to use the RNase cleavage method combined with PCR for large-scale screening of variation in chromosomal DNA. (J.P.N.)

Overaccumulation of the chloroplast antisense RNA AS5 is correlated with decreased abundance of 5S rRNA in vivo and inefficient 5S rRNA maturation in vitro

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Sharwood, Robert E.; Hotto, Amber M.; Bollenbach, Thomas J.; Stern, David B.

2011-01-01

Post-transcriptional regulation in the chloroplast is exerted by nucleus-encoded ribonucleases and RNA-binding proteins. One of these ribonucleases is RNR1, a 3′-to-5′ exoribonuclease of the RNase II family. We have previously shown that Arabidopsis rnr1-null mutants exhibit specific abnormalities in the expression of the rRNA operon, including the accumulation of precursor 23S, 16S, and 4.5S species and a concomitant decrease in the mature species. 5S rRNA transcripts, however, accumulate to a very low level in both precursor and mature forms, suggesting that they are unstable in the rnr1 background. Here we demonstrate that rnr1 plants overaccumulate an antisense RNA, AS5, that is complementary to the 5S rRNA, its intergenic spacer, and the downstream trnR gene, which encodes tRNAArg, raising the possibility that AS5 destabilizes 5S rRNA or its precursor and/or blocks rRNA maturation. To investigate this, we used an in vitro system that supports 5S rRNA and trnR processing. We show that AS5 inhibits 5S rRNA maturation from a 5S-trnR precursor, and shorter versions of AS5 demonstrate that inhibition requires intergenic sequences. To test whether the sense and antisense RNAs form double-stranded regions in vitro, treatment with the single-strand-specific mung bean nuclease was used. These results suggest that 5S–AS5 duplexes interfere with a sense-strand secondary structure near the endonucleolytic cleavage site downstream from the 5S rRNA coding region. We hypothesize that these duplexes are degraded by a dsRNA-specific ribonuclease in vivo, contributing to the 5S rRNA deficiency observed in rnr1. PMID:21148395

Harvesting full-duplex rate gains in cellular networks with half-duplex user terminals

KAUST Repository

AlAmmouri, Ahmad

2016-07-26

Full-Duplex (FD) transceivers may be expensive in terms of complexity, power consumption, and price to be implemented in all user terminals. Therefore, techniques to exploit in-band full-duplex communication with FD base stations (BSs) and half-duplex (HD) users\\' equipment (UEs) are required. In this context, 3-node topology (3NT) has been recently proposed for FD BSs to reuse the uplink (UL) and downlink (DL) channels with HD terminals within the same cell. In this paper, we present a tractable mathematical framework, based on stochastic geometry, for 3NT in cellular networks. To this end, we propose a design paradigm via pulse-shaping and partial overlap between UL and DL channels to maximize the harvested rate gains in 3NT. The results show that 3NT achieves a close performance to networks with FD BSs and FD UEs, denoted by 2-node topology (2NT) networks. A maximum of 5% rate loss is reported when 3NT is compared to 2NT with efficient self-interference cancellation (SIC). If the SIC in 2NT is not efficient, 3NT highly outperforms 2NT. Consequently, we conclude that, irrespective to the UE duplexing scheme, it is sufficient to have FD BSs to harvest FD rate gains.

2'β-Fluoro-Tricyclo Nucleic Acids (2'F-tc-ANA): Thermal Duplex Stability, Structural Studies, and RNase H Activation.

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Istrate, Alena; Katolik, Adam; Istrate, Andrei; Leumann, Christian J

2017-08-01

We describe the synthesis, thermal stability, structural and RNase H activation properties of 2'β-fluoro-tricyclo nucleic acids (2'F-tc-ANA). Three 2'F-tc-ANA nucleosides (T, 5Me C and A) were synthesized starting from a previously described fluorinated tricyclo sugar intermediate. NMR analysis and quantum mechanical calculations indicate that 2'F-tc-ANA nucleosides prefer sugar conformations in the East and South regions of the pseudorotational cycle. UV-melting experiments revealed that non-consecutive insertions of 2'F-tc-ANA units in DNA reduce the affinity to DNA and RNA complements. However, an oligonucleotide with five contiguous 2'F-tc-ANA-T insertions exhibits increased affinity to complementary RNA. Moreover, a fully modified 10-mer 2'F-tc-ANA oligonucleotide paired to both DNA (+1.6 °C/mod) and RNA (+2.5 °C/mod) with significantly higher affinity compared to corresponding unmodified DNA, and similar affinity compared to corresponding tc-DNA. In addition, CD spectroscopy and molecular dynamics simulations indicate that the conformation of the 2'F-tc-ANA/RNA duplex is similar to that of a DNA/RNA duplex. Moreover, in some sequence contexts, 2'F-tc-ANA promotes RNase H-mediated cleavage of a complementary RNA strand. Taken together, 2'F-tc-ANA represents a nucleic acid analogue that offers the advantage of high RNA affinity while maintaining the ability to activate RNase H, and can be considered a prospective candidate for gene silencing applications. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Duplex kidney: not just a drooping lily.

Science.gov (United States)

Doery, Ashlea J; Ang, Eileen; Ditchfield, Michael R

2015-04-01

Duplex kidneys are common, mostly asymptomatic and of no clinical significance. However, they can be associated with significant pathology, often with long-term morbidity. There is minimal literature on the review of the duplex kidney, its associated anomalies and complications. The purpose of this paper is to review our experience of imaging the spectrum of abnormalities associated with duplex kidneys in the paediatric population and correlate this with contemporary literature. A retrospective review of the radiology database in a tertiary paediatric centre was performed. A word search of the Radiology Information System for 'duplex' of patients under the age of 16 was undertaken and limited to studies performed between 2006 and 2013. Two hundred seventy-four patients were identified (age range 0-16, median 3 years, gender 59.9% female) who had 836 studies: ultrasound 598/836 (71.6%), nuclear medicine 180/836 (21.5%), micturating cystourethrogram 52/836 (6.2%), MRI 5/836 (duplex and no complication (151/274 = 55.1%), upper moiety obstruction, lower moiety reflux/scarring, multicystic dysplastic kidney, abnormal ureteric insertion and other pathology. Duplex kidneys are common and often not clinically significant. However, this study demonstrates almost 50% of paediatric patients investigated for duplex kidneys had complications requiring treatment. The most common complications were upper moiety obstruction associated with a ureterocele and lower moiety vesicoureteric reflux. Ultrasound was the most common modality for early detection of these complications. © 2015 The Royal Australian and New Zealand College of Radiologists.

Full Duplex Communications in 5G Small Cells

DEFF Research Database (Denmark)

Mahmood, Nurul Huda; Gatnau, Marta; Berardinelli, Gilberto

2017-01-01

Full duplex communication promises system performance improvement over conventional half duplex communication by allowing simultaneous transmission and reception. However, such concurrent communication results in strong self interference and an increase in the overall network interference, and can...... only be exploited when traffic is available in both directions. The potential throughput gains of full duplex communication over conventional half duplex transmission in a small cell network with asymmetric traffic conditions is investigated in this contribution. The throughput performance gains...... are analysed using tools from stochastic geometry, and further confirmed through extensive system level simulations. Our findings explicitly quantify how the gains from full duplex communication depend on the traffic profile and the inter-cell interference coupling. The demonstrated throughput gains and delay...

Towards Antiviral shRNAs Based on the AgoshRNA Design.

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Ying Poi Liu

Full Text Available RNA interference (RNAi can be induced by intracellular expression of a short hairpin RNA (shRNA. Processing of the shRNA requires the RNaseIII-like Dicer enzyme to remove the loop and to release the biologically active small interfering RNA (siRNA. Dicer is also involved in microRNA (miRNA processing to liberate the mature miRNA duplex, but recent studies indicate that miR-451 is not processed by Dicer. Instead, this miRNA is processed by the Argonaute 2 (Ago2 protein, which also executes the subsequent cleavage of a complementary mRNA target. Interestingly, shRNAs that structurally resemble miR-451 can also be processed by Ago2 instead of Dicer. The key determinant of these "AgoshRNA" molecules is a relatively short basepaired stem, which avoids Dicer recognition and consequently allows alternative processing by Ago2. AgoshRNA processing yields a single active RNA strand, whereas standard shRNAs produce a duplex with guide and passenger strands and the latter may cause adverse off-target effects. In this study, we converted previously tested active anti-HIV-1 shRNA molecules into AgoshRNA. We tested several designs that could potentially improve AgoshRNA activity, including extension of the complementarity between the guide strand and the mRNA target and reduction of the thermodynamic stability of the hairpins. We demonstrate that active AgoshRNAs can be generated. However, the RNAi activity is reduced compared to the matching shRNAs. Despite reduced RNAi activity, comparison of an active AgoshRNA and the matching shRNA in a sensitive cell toxicity assay revealed that the AgoshRNA is much less toxic.

Model for an RNA tertiary interaction from the structure of an intermolecular complex between a GAAA tetraloop and an RNA helix.

Science.gov (United States)

Pley, H W; Flaherty, K M; McKay, D B

1994-11-03

In large structured RNAs, RNA hairpins in which the strands of the duplex stem are connected by a tetraloop of the consensus sequence 5'-GNRA (where N is any nucleotide, and R is either G or A) are unusually frequent. In group I introns there is a covariation in sequence between nucleotides in the third and fourth positions of the loop with specific distant base pairs in putative RNA duplex stems: GNAA loops correlate with successive 5'-C-C.G-C base pairs in stems, whereas GNGA loops correlate with 5'-C-U.G-A. This has led to the suggestion that GNRA tetraloops may be involved in specific long-range tertiary interactions, with each A in position 3 or 4 of the loop interacting with a C-G base pair in the duplex, and G in position 3 interacting with a U-A base pair. This idea is supported experimentally for the GAAA loop of the P5b extension of the group I intron of Tetrahymena thermophila and the L9 GUGA terminal loop of the td intron of bacteriophage T4 (ref. 4). NMR has revealed the overall structure of the tetraloop for 12-nucleotide hairpins with GCAA and GAAA loops and models have been proposed for the interaction of GNRA tetraloops with base pairs in the minor groove of A-form RNA. Here we describe the crystal structure of an intermolecular complex between a GAAA tetraloop and an RNA helix. The interactions we observe correlate with the specificity of GNRA tetraloops inferred from phylogenetic studies, suggesting that this complex is a legitimate model for intramolecular tertiary interactions mediated by GNRA tetraloops in large structured RNAs.

Hypothesis: A Role for Fragile X Mental Retardation Protein in Mediating and Relieving MicroRNA-Guided Translational Repression?

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Isabelle Plante

2006-01-01

Full Text Available MicroRNA (miRNA-guided messenger RNA (mRNA translational repression is believed to be mediated by effector miRNA-containing ribonucleoprotein (miRNP complexes harboring fragile X mental retardation protein (FMRP. Recent studies documented the nucleic acid chaperone properties of FMRP and characterized its role and importance in RNA silencing in mammalian cells. We propose a model in which FMRP could facilitate miRNA assembly on target mRNAs in a process involving recognition of G quartet structures. Functioning within a duplex miRNP, FMRP may also mediate mRNA targeting through a strand exchange mechanism, in which the miRNA* of the duplex is swapped for the mRNA. Furthermore, FMRP may contribute to the relief of miRNA-guided mRNA repression through a reverse strand exchange reaction, possibly initiated by a specific cellular signal, that would liberate the mRNA for translation. Suboptimal utilization of miRNAs may thus account for some of themolecular defects in patients with the fragile X syndrome.

Efficient construction of an inverted minimal H1 promoter driven siRNA expression cassette: facilitation of promoter and siRNA sequence exchange.

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Hoorig Nassanian

2007-08-01

Full Text Available RNA interference (RNAi, mediated by small interfering RNA (siRNA, is an effective method used to silence gene expression at the post-transcriptional level. Upon introduction into target cells, siRNAs incorporate into the RNA-induced silencing complex (RISC. The antisense strand of the siRNA duplex then "guides" the RISC to the homologous mRNA, leading to target degradation and gene silencing. In recent years, various vector-based siRNA expression systems have been developed which utilize opposing polymerase III promoters to independently drive expression of the sense and antisense strands of the siRNA duplex from the same template.We show here the use of a ligase chain reaction (LCR to develop a new vector system called pInv-H1 in which a DNA sequence encoding a specific siRNA is placed between two inverted minimal human H1 promoters (approximately 100 bp each. Expression of functional siRNAs from this construct has led to efficient silencing of both reporter and endogenous genes. Furthermore, the inverted H1 promoter-siRNA expression cassette was used to generate a retrovirus vector capable of transducing and silencing expression of the targeted protein by>80% in target cells.The unique design of this construct allows for the efficient exchange of siRNA sequences by the directional cloning of short oligonucleotides via asymmetric restriction sites. This provides a convenient way to test the functionality of different siRNA sequences. Delivery of the siRNA cassette by retroviral transduction suggests that a single copy of the siRNA expression cassette efficiently knocks down gene expression at the protein level. We note that this vector system can potentially be used to generate a random siRNA library. The flexibility of the ligase chain reaction suggests that additional control elements can easily be introduced into this siRNA expression cassette.

Development of a one-step duplex RT-qPCR for the quantification of phocine distemper virus.

Science.gov (United States)

Bogomolni, Andrea L; Frasca, Salvatore; Matassa, Keith A; Nielsen, Ole; Rogers, Kara; De Guise, Sylvain

2015-04-01

Worldwide, stranded marine mammals and the network personnel who respond to marine mammal mortality have provided much of the information regarding marine morbillivirus infections. An assay to determine the amount of virus present in tissue samples would be useful to assist in routine surveying of animal health and for monitoring large-scale die-off events. False negatives from poor-quality samples prevent determination of the true extent of infection, while only small amounts of tissue samples or archived RNA may be available at the time of collection for future retrospective analysis. We developed a one-step duplex real-time reverse transcriptase-quantitative-PCR assay (RT-qPCR) based on Taqman probe technology to quantify phocine distemper virus (PDV) isolated from an outbreak in harbor (Phoca vitulina concolor) and gray seals (Halichoerus grypus) along the northeast US coast in 2006. The glyceraldehyde-3-phosphate-dehydrogenase (GAPDH) gene was selected to assess RNA quality. This duplex assay is specific for PDV and sensitive through a range of 10(0) to 10(9) copies ds-plasmid DNA. For the GAPDH target, the reaction in duplex amplified 10(0) to 10(9) copies of ds-plasmid DNA and was detectable in multiple seal species. This assay reduced the likelihood of false negative results due to degradation of tissues and well-to-well variability while providing sensitive and specific detection of PDV, which would be applicable in molecular epidemiologic studies and pathogen detection in field and laboratory investigations involving a variety of seal species.

Determination of Resistant Starch Assimilating Bacteria in Fecal Samples of Mice by In vitro RNA-Based Stable Isotope Probing

Science.gov (United States)

Herrmann, Elena; Young, Wayne; Rosendale, Douglas; Conrad, Ralf; Riedel, Christian U.; Egert, Markus

2017-01-01

The impact of the intestinal microbiota on human health is becoming increasingly appreciated in recent years. In consequence, and fueled by major technological advances, the composition of the intestinal microbiota in health and disease has been intensively studied by high throughput sequencing approaches. Observations linking dysbiosis of the intestinal microbiota with a number of serious medical conditions including chronic inflammatory disorders and allergic diseases suggest that restoration of the composition and activity of the intestinal microbiota may be a treatment option at least for some of these diseases. One possibility to shape the intestinal microbiota is the administration of prebiotic carbohydrates such as resistant starch (RS). In the present study, we aim at establishing RNA-based stable isotope probing (RNA-SIP) to identify bacterial populations that are involved in the assimilation of RS using anaerobic in vitro fermentation of murine fecal material with stable [U13C] isotope-labeled potato starch. Total RNA from these incubations was extracted, processed by gradient ultracentrifugation and fractionated by density. 16S rRNA gene sequences were amplified from reverse transcribed RNA of high and low density fractions suspected to contain labeled and unlabeled RNA, respectively. Phylogenetic analysis of the obtained sequences revealed a distinct subset of the intestinal microbiota involved in starch metabolism. The results suggest Bacteroidetes, in particular genera affiliated with Prevotellaceae, as well as members of the Ruminococcacea family to be primary assimilators of resistant starch due to a significantly higher relative abundance in higher density fractions in RNA samples isolated after 2 h of incubation. Using high performance liquid chromatography coupled to isotope ratio mass spectrometry (HPLC-IRMS) analysis, some stable isotope label was recovered from acetate, propionate and butyrate. Here, we demonstrate the suitability of RNA

Determination of Resistant Starch Assimilating Bacteria in Fecal Samples of Mice by In vitro RNA-Based Stable Isotope Probing

Directory of Open Access Journals (Sweden)

Elena Herrmann

2017-07-01

Full Text Available The impact of the intestinal microbiota on human health is becoming increasingly appreciated in recent years. In consequence, and fueled by major technological advances, the composition of the intestinal microbiota in health and disease has been intensively studied by high throughput sequencing approaches. Observations linking dysbiosis of the intestinal microbiota with a number of serious medical conditions including chronic inflammatory disorders and allergic diseases suggest that restoration of the composition and activity of the intestinal microbiota may be a treatment option at least for some of these diseases. One possibility to shape the intestinal microbiota is the administration of prebiotic carbohydrates such as resistant starch (RS. In the present study, we aim at establishing RNA-based stable isotope probing (RNA-SIP to identify bacterial populations that are involved in the assimilation of RS using anaerobic in vitro fermentation of murine fecal material with stable [U13C] isotope-labeled potato starch. Total RNA from these incubations was extracted, processed by gradient ultracentrifugation and fractionated by density. 16S rRNA gene sequences were amplified from reverse transcribed RNA of high and low density fractions suspected to contain labeled and unlabeled RNA, respectively. Phylogenetic analysis of the obtained sequences revealed a distinct subset of the intestinal microbiota involved in starch metabolism. The results suggest Bacteroidetes, in particular genera affiliated with Prevotellaceae, as well as members of the Ruminococcacea family to be primary assimilators of resistant starch due to a significantly higher relative abundance in higher density fractions in RNA samples isolated after 2 h of incubation. Using high performance liquid chromatography coupled to isotope ratio mass spectrometry (HPLC-IRMS analysis, some stable isotope label was recovered from acetate, propionate and butyrate. Here, we demonstrate the

Synthesis and conformational properties of oligonucleotides incorporating 2'-O-phosphorylated ribonucleotides as structural motifs of pre-tRNA splicing intermediates.

Science.gov (United States)

Tsuruoka, H; Shohda, K; Wada, T; Sekine, M

2000-11-03

To synthesize oligonucleotides containing 2'-O-phosphate groups, four kinds of ribonucleoside 3'-phosphoramidite building blocks 6a-d having the bis(2-cyano-1,1-dimethylethoxy)thiophosphoryl (BCMETP) group were prepared according to our previous phosphorylation procedure. These phosphoramidite units 6a-d were not contaminated with 3'-regioisomers and were successfully applied to solid-phase synthesis to give oligodeoxyuridylates 15, 16 and oligouridylates 21, 22. Self-complementary Drew-Dickerson DNA 12mers 24-28 replaced by a 2'-O-phosphorylated ribonucleotide at various positions were similarly synthesized. In these syntheses, it turned out that KI(3) was the most effective reagent for oxidative desulfurization of the initially generated thiophosphate group to the phosphate group on polymer supports. Without using this conversion step, a tridecadeoxyuridylate 17 incorporating a 2'-O-thiophosphorylated uridine derivative was also synthesized. To investigate the effect of the 2'-phosphate group on the thermal stability and 3D-structure of DNA(RNA) duplexes, T(m) measurement of the self-complementary oligonucleotides obtained and MD simulation of heptamer duplexes 33-36 were carried out. According to these analyses, it was suggested that the nucleoside ribose moiety phosphorylated at the 2'-hydroxyl function predominantly preferred C2'-endo to C3'-endo conformation in DNA duplexes so that it did not significantly affect the stability of the DNA duplex. On the other hand, the 2'-modified ribose moiety was expelled to give a C3'-endo conformation in RNA duplexes so that the RNA duplexes were extremely destabilized.

G-quadruplexes Significantly Stimulate Pif1 Helicase-catalyzed Duplex DNA Unwinding*

Science.gov (United States)

Duan, Xiao-Lei; Liu, Na-Nv; Yang, Yan-Tao; Li, Hai-Hong; Li, Ming; Dou, Shuo-Xing; Xi, Xu-Guang

2015-01-01

The evolutionarily conserved G-quadruplexes (G4s) are faithfully inherited and serve a variety of cellular functions such as telomere maintenance, gene regulation, DNA replication initiation, and epigenetic regulation. Different from the Watson-Crick base-pairing found in duplex DNA, G4s are formed via Hoogsteen base pairing and are very stable and compact DNA structures. Failure of untangling them in the cell impedes DNA-based transactions and leads to genome instability. Cells have evolved highly specific helicases to resolve G4 structures. We used a recombinant nuclear form of Saccharomyces cerevisiae Pif1 to characterize Pif1-mediated DNA unwinding with a substrate mimicking an ongoing lagging strand synthesis stalled by G4s, which resembles a replication origin and a G4-structured flap in Okazaki fragment maturation. We find that the presence of G4 may greatly stimulate the Pif1 helicase to unwind duplex DNA. Further studies reveal that this stimulation results from G4-enhanced Pif1 dimerization, which is required for duplex DNA unwinding. This finding provides new insights into the properties and functions of G4s. We discuss the observed activation phenomenon in relation to the possible regulatory role of G4s in the rapid rescue of the stalled lagging strand synthesis by helping the replicator recognize and activate the replication origin as well as by quickly removing the G4-structured flap during Okazaki fragment maturation. PMID:25627683

Buffer management in wireless full-duplex systems

KAUST Repository

Bouacida, Nader; Showail, Ahmad; Shihada, Basem

2015-01-01

, we address the problem of buffer management in full-duplex networks by using Wireless Queue Management (WQM), which is an active queue management technique for wireless networks. Our solution is based on Relay Full-Duplex MAC (RFD

Energy balance and deformation mechanisms of duplexes

Science.gov (United States)

Mitra, Gautam; Boyer, Steven E.

A duplex consists of a series of imbricate faults that are asymptotic to a roof thrust and a floor thrust. Depending on the final orientations of the imbricate faults and the final position of the branch lines, a duplex may be hinterland-dipping, foreland-dipping, or an antiformal stack. The exact geometry depends on various factors such as the initial dimensions of the individual slices (horses), their lithology, the amount of displacement (normalized to size of horse) on each fault, and the mechanics of movement along each fault. The energy required in duplex formation can be determined by calculating the total work involved in emplacing each horse: this is given by where W t=W p+W b+W g+W iWp is the work involved in initiating and propagating a fracture. Wb is the work involved in basal sliding, which may be frictional or some form of ductile flow, Wg is the work done against gravity during the emplacement of the horse, and Wi is the work involved in the internal deformation of the horse. By calculating and comparing these work terms it is possible to predict the conditions under which the different types of duplexes will form. Normally, the development of a hinterland-dipping duplex is most likely. However, if deformation conditions are favorable, displacements on individual imbricate faults may be very large compared to the size of the horses, leading to the formation of either antiformal stacks or foreland-dipping duplexes.

Duplex ultrasound surveillance after carotid artery endarterectomy.

Science.gov (United States)

Al Shakarchi, Julien; Lowry, Danielle; Nath, Jay; Khawaja, Aurangzaib Z; Inston, Nicholas; Tiwari, Alok

2016-06-01

After carotid endarterectomy (CEA), patients have been regularly followed up by duplex ultrasound imaging. However, the evidence for long-term follow-up is not clear, especially if the results from an early duplex scan are normal. This study assessed and systematically reviewed the evidence base for long-term surveillance after CEA and a normal early scan. Electronic databases were searched for studies assessing duplex surveillance after CEA in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The primary outcome for this study was the incidence of restenosis after a normal early scan. The secondary outcome was the number of reinterventions after a normal early scan. The review included seven studies that reported 2317 procedures. Of those patients with a normal early scan, 2.8% (95% confidence interval, 0.7%-6%) developed a restenosis, and 0.4% (95% confidence interval, 0%-0.9%) underwent a reintervention for their restenosis during the follow-up period. This review confirms that routine postoperative duplex ultrasound surveillance after CEA is not necessary if the early duplex scan is normal. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Staphylococcus aureus RNAIII binds to two distant regions of coa mRNA to arrest translation and promote mRNA degradation.

Directory of Open Access Journals (Sweden)

Clément Chevalier

2010-03-01

Full Text Available Staphylococcus aureus RNAIII is the intracellular effector of the quorum sensing system that temporally controls a large number of virulence factors including exoproteins and cell-wall-associated proteins. Staphylocoagulase is one major virulence factor, which promotes clotting of human plasma. Like the major cell surface protein A, the expression of staphylocoagulase is strongly repressed by the quorum sensing system at the post-exponential growth phase. Here we used a combination of approaches in vivo and in vitro to analyze the mechanism used by RNAIII to regulate the expression of staphylocoagulase. Our data show that RNAIII represses the synthesis of the protein through a direct binding with the mRNA. Structure mapping shows that two distant regions of RNAIII interact with coa mRNA and that the mRNA harbors a conserved signature as found in other RNAIII-target mRNAs. The resulting complex is composed of an imperfect duplex masking the Shine-Dalgarno sequence of coa mRNA and of a loop-loop interaction occurring downstream in the coding region. The imperfect duplex is sufficient to prevent the formation of the ribosomal initiation complex and to repress the expression of a reporter gene in vivo. In addition, the double-strand-specific endoribonuclease III cleaves the two regions of the mRNA bound to RNAIII that may contribute to the degradation of the repressed mRNA. This study validates another direct target of RNAIII that plays a role in virulence. It also illustrates the diversity of RNAIII-mRNA topologies and how these multiple RNAIII-mRNA interactions would mediate virulence regulation.

Genome-Wide Analysis of the RNA Helicase Gene Family in Gossypium raimondii

Directory of Open Access Journals (Sweden)

Jie Chen

2014-03-01

Full Text Available The RNA helicases, which help to unwind stable RNA duplexes, and have important roles in RNA metabolism, belong to a class of motor proteins that play important roles in plant development and responses to stress. Although this family of genes has been the subject of systematic investigation in Arabidopsis, rice, and tomato, it has not yet been characterized in cotton. In this study, we identified 161 putative RNA helicase genes in the genome of the diploid cotton species Gossypium raimondii. We classified these genes into three subfamilies, based on the presence of either a DEAD-box (51 genes, DEAH-box (52 genes, or DExD/H-box (58 genes in their coding regions. Chromosome location analysis showed that the genes that encode RNA helicases are distributed across all 13 chromosomes of G. raimondii. Syntenic analysis revealed that 62 of the 161 G. raimondii helicase genes (38.5% are within the identified syntenic blocks. Sixty-six (40.99% helicase genes from G. raimondii have one or several putative orthologs in tomato. Additionally, GrDEADs have more conserved gene structures and more simple domains than GrDEAHs and GrDExD/Hs. Transcriptome sequencing data demonstrated that many of these helicases, especially GrDEADs, are highly expressed at the fiber initiation stage and in mature leaves. To our knowledge, this is the first report of a genome-wide analysis of the RNA helicase gene family in cotton.

Terminal structures of West Nile virus genomic RNA and their interactions with viral NS5 protein

International Nuclear Information System (INIS)

Dong Hongping; Zhang Bo; Shi Peiyong

2008-01-01

Genome cyclization is essential for flavivirus replication. We used RNases to probe the structures formed by the 5'-terminal 190 nucleotides and the 3'-terminal 111 nucleotides of the West Nile virus (WNV) genomic RNA. When analyzed individually, the two RNAs adopt stem-loop structures as predicted by the thermodynamic-folding program. However, when mixed together, the two RNAs form a duplex that is mediated through base-pairings of two sets of RNA elements (5'CS/3'CSI and 5'UAR/3'UAR). Formation of the RNA duplex facilitates a conformational change that leaves the 3'-terminal nucleotides of the genome (position - 8 to - 16) to be single-stranded. Viral NS5 binds specifically to the 5'-terminal stem-loop (SL1) of the genomic RNA. The 5'SL1 RNA structure is essential for WNV replication. The study has provided further evidence to suggest that flavivirus genome cyclization and NS5/5'SL1 RNA interaction facilitate NS5 binding to the 3' end of the genome for the initiation of viral minus-strand RNA synthesis

Assessment of Duplex PCR for the simultaneous diagnose of Mycobacterium spp. and Brucella spp. in cattle

Directory of Open Access Journals (Sweden)

Ariel Escobar

2013-03-01

Full Text Available Tuberculosis and brucellosis remain important causes of morbidity and mortality in many countries, for the detection of both diseases requires efficient and sensitive tool for effectuate the diagnosis. This study was aimed to evaluate and compare the duplex PCR versus the nested PCR, for detection of Brucella spp. (BR and Mycobacterium spp. (TB. A total of 100 samples of tissues from tracheo-bronchial lymph nodes, bovine lung and bacterial isolate as positive controls were used. Were evaluated ten combinations of primers which were designed to flank the segment of the 16S rRNA sequence (RB and antigen gen MPB70 (TB, the best result for the Duplex PCR was obtained with the primers Bru-2F/Bru-2R for BR and Tub-1F/Tub-N-R for TB. The amplification of the products was 225 and 230-bp respectively. In order to compare the results of the proposed technique, all samples were initially analyzed and compared between PCR and nested PCR (Kappa, k = 0.85 and the concordance between Duplex PCR and nested PCR (k = 0.88 for the two bacteria was very good.

On the Performance of In-Band Full-Duplex Cooperative Communications

KAUST Repository

Khafagy, Mohammad Galal

2016-01-01

-duplex potentials. Full-duplex relaying (FDR), where intermediate nodes may now support source-destination communication via simultaneous listening/forwarding, represents one of two full-duplex settings currently recommended for deployment in future fifth

A stable RNA virus-based vector for citrus trees

International Nuclear Information System (INIS)

Folimonov, Alexey S.; Folimonova, Svetlana Y.; Bar-Joseph, Moshe; Dawson, William O.

2007-01-01

Virus-based vectors are important tools in plant molecular biology and plant genomics. A number of vectors based on viruses that infect herbaceous plants are in use for expression or silencing of genes in plants as well as screening unknown sequences for function. Yet there is a need for useful virus-based vectors for woody plants, which demand much greater stability because of the longer time required for systemic infection and analysis. We examined several strategies to develop a Citrus tristeza virus (CTV)-based vector for transient expression of foreign genes in citrus trees using a green fluorescent protein (GFP) as a reporter. These strategies included substitution of the p13 open reading frame (ORF) by the ORF of GFP, construction of a self-processing fusion of GFP in-frame with the major coat protein (CP), or expression of the GFP ORF as an extra gene from a subgenomic (sg) mRNA controlled either by a duplicated CTV CP sgRNA controller element (CE) or an introduced heterologous CE of Beet yellows virus. Engineered vector constructs were examined for replication, encapsidation, GFP expression during multiple passages in protoplasts, and for their ability to infect, move, express GFP, and be maintained in citrus plants. The most successful vectors based on the 'add-a-gene' strategy have been unusually stable, continuing to produce GFP fluorescence after more than 4 years in citrus trees

Development of a duplex real-time RT-PCR for the simultaneous detection and differentiation of Theiler's murine encephalomyelitis virus and rat theilovirus.

Science.gov (United States)

Yuan, Wen; Wang, Jing; Xu, Fengjiao; Huang, Bihong; Lian, Yuexiao; Rao, Dan; Yin, Xueqin; Wu, Miaoli; Zhu, Yujun; Zhang, Yu; Huang, Ren; Guo, Pengju

2016-10-01

Theiler's murine encephalomyelitis virus (TMEV) and rat theilovirus (RTV), the member of the genus Cardiovirus, are widespread in laboratory mice and rats, and are potential contaminants of biological materials. Cardioviruses infection may cause serious complications in biomedical research. To improve the efficiency of routine screening for Cardioviruses infection, a duplex real-time reverse transcriptase polymerase chain reaction (RT-PCR) assay was developed for simultaneous detection and differentiation of TMEV and RTV. The duplex assay was specific for reference strains of TMEV and RTV, and no cross-reaction was found with seven other rodent viruses. The limits of detection of both TMEV and RTV were 4×10(1) copies RNA/reaction. Reproducibility was estimated using standard dilutions, with coefficients of variation duplex real-time RT-PCR and conventional RT-PCR. For 439 clinical samples，95 samples were positive for TMEV and 72 samples were positive for RTV using duplex real-time RT-PCR approach, whereas only 77 samples were positive for TMEV and 66 samples were positive for RTV when conventional RT-PCR was applied. Mixed infections were found in 20 samples when analyzed by conventional RT-PCR whereas 30 samples were found to be mixed infection when duplex real-time RT-PCR was applied. This duplex assay provides a useful tool for routine health monitoring and screening of contaminated biological materials of these two viruses. Copyright © 2016 Elsevier B.V. All rights reserved.

Full-Duplex MIMO Small-Cell Networks: Performance Analysis

OpenAIRE

Atzeni, Italo; Kountouris, Marios

2015-01-01

Full-duplex small-cell relays with multiple antennas constitute a core element of the envisioned 5G network architecture. In this paper, we use stochastic geometry to analyze the performance of wireless networks with full-duplex multiple-antenna small cells, with particular emphasis on the probability of successful transmission. To achieve this goal, we additionally characterize the distribution of the self-interference power of the full-duplex nodes. The proposed framework reveals useful ins...

Structural insights into mechanisms of the small RNA methyltransferase HEN1

Energy Technology Data Exchange (ETDEWEB)

Huang, Ying; Ji, Lijuan; Huang, Qichen; Vassylyev, Dmitry G.; Chen, Xuemei; Ma, Jin-Biao; (UAB); (UCR)

2010-02-22

RNA silencing is a conserved regulatory mechanism in fungi, plants and animals that regulates gene expression and defence against viruses and transgenes. Small silencing RNAs of {approx}20-30 nucleotides and their associated effector proteins, the Argonaute family proteins, are the central components in RNA silencing. A subset of small RNAs, such as microRNAs and small interfering RNAs (siRNAs) in plants, Piwi-interacting RNAs in animals and siRNAs in Drosophila, requires an additional crucial step for their maturation; that is, 2'-O-methylation on the 3' terminal nucleotide. A conserved S-adenosyl-L-methionine-dependent RNA methyltransferase, HUA ENHANCER 1 (HEN1), and its homologues are responsible for this specific modification. Here we report the 3.1 {angstrom} crystal structure of full-length HEN1 from Arabidopsis in complex with a 22-nucleotide small RNA duplex and cofactor product S-adenosyl-L-homocysteine. Highly cooperative recognition of the small RNA substrate by multiple RNA binding domains and the methyltransferase domain in HEN1 measures the length of the RNA duplex and determines the substrate specificity. Metal ion coordination by both 2' and 3' hydroxyls on the 3'-terminal nucleotide and four invariant residues in the active site of the methyltransferase domain suggests a novel Mg{sup 2+}-dependent 2'-O-methylation mechanism.

Programmed self-assembly of DNA/RNA for biomedical applications

Science.gov (United States)

Wang, Pengfei

Three self-assembly strategies were utilized for assembly of novel functional DNA/RNA nanostructures. RNA-DNA hybrid origami method was developed to fabricate nano-objects (ribbon, rectangle, and triangle) with precisely controlled geometry. Unlike conventional DNA origami which use long DNA single strand as scaffold, a long RNA single strand was used instead, which was folded by short DNA single strands (staples) into prescribed objects through sequence specific hybridization between RNA and DNA. Single stranded tiles (SST) and RNA-DNA hybrid origami were utilized to fabricate a variety of barcode-like nanostructures with unique patterns by expanding a plain rectangle via introducing spacers (10-bp dsDNA segment) between parallel duplexes. Finally, complex 2D array and 3D polyhedrons with multiple patterns within one structure were assembled from simple DNA motifs. Two demonstrations of biomedical applications of DNA nanotechnology were presented. Firstly, lambda-DNA was used as template to direct the fabrication of multi-component magnetic nanoparticle chains. Nuclear magnetic relaxation (NMR) characterization showed superb magnetic relaxativity of the nanoparticle chains which have large potential to be utilized as MRI contrast agents. Secondly, DNA nanotechnology was introduced into the conformational study of a routinely used catalytic DNAzyme, the RNA-cleaving 10-23 DNAzyme. The relative angle between two flanking duplexes of the catalytic core was determined (94.8°), which shall be able to provide a clue to further understanding of the cleaving mechanism of this DNAzyme from a conformational perspective.

Improved nucleic acid descriptors for siRNA efficacy prediction.

Science.gov (United States)

Sciabola, Simone; Cao, Qing; Orozco, Modesto; Faustino, Ignacio; Stanton, Robert V

2013-02-01

Although considerable progress has been made recently in understanding how gene silencing is mediated by the RNAi pathway, the rational design of effective sequences is still a challenging task. In this article, we demonstrate that including three-dimensional descriptors improved the discrimination between active and inactive small interfering RNAs (siRNAs) in a statistical model. Five descriptor types were used: (i) nucleotide position along the siRNA sequence, (ii) nucleotide composition in terms of presence/absence of specific combinations of di- and trinucleotides, (iii) nucleotide interactions by means of a modified auto- and cross-covariance function, (iv) nucleotide thermodynamic stability derived by the nearest neighbor model representation and (v) nucleic acid structure flexibility. The duplex flexibility descriptors are derived from extended molecular dynamics simulations, which are able to describe the sequence-dependent elastic properties of RNA duplexes, even for non-standard oligonucleotides. The matrix of descriptors was analysed using three statistical packages in R (partial least squares, random forest, and support vector machine), and the most predictive model was implemented in a modeling tool we have made publicly available through SourceForge. Our implementation of new RNA descriptors coupled with appropriate statistical algorithms resulted in improved model performance for the selection of siRNA candidates when compared with publicly available siRNA prediction tools and previously published test sets. Additional validation studies based on in-house RNA interference projects confirmed the robustness of the scoring procedure in prospective studies.

Development of a duplex droplet digital PCR assay for absolute quantitative detection of "Candidatus Liberibacter asiaticus".

Science.gov (United States)

Selvaraj, Vijayanandraj; Maheshwari, Yogita; Hajeri, Subhas; Chen, Jianchi; McCollum, Thomas Greg; Yokomi, Raymond

2018-01-01

Huanglongbing (HLB, citrus greening) is a devastating citrus disease affecting citrus production worldwide. It is associated with the bacterium "Candidatus Liberibacter asiaticus" (CLas) and is vectored by the Asian citrus psyllid (ACP). Currently, diagnosis of CLas in regulatory samples is based on real-time quantitative polymerase chain reaction (qPCR) using 16S rRNA gene specific primers/probe. The detection of CLas using qPCR is challenging due to low pathogen titer and uneven distribution in infected plants and exacerbated by sampling issues and presence of inhibitors. This study evaluated a duplex droplet digital polymerase chain reaction (ddPCR) using multi-copy gene targets, 16S and RNR, to simultaneously detect CLas DNA targets in the same sample for unambiguous detection of the HLB pathogen in DNA extracts from citrus leaves and ACP. Standard curve analyses on tenfold dilution series with plasmid, citrus leaf and ACP DNA showed that both ddPCR and qPCR exhibited good linearity and efficiency in the duplex assay. CLas-infected low titer samples were used to validate the duplex ddPCR and qPCR performance and demonstrated that detection rate is higher when both 16S and RNR primers were used in duplex assay. However, the receiver operating characteristic analysis indicated that area under the curve for RNR primer was significantly broader, compared to 16S primers for CLas detection at low target titer. The absolute quantification of CLas at variable titers was reproducible and repeatable for both primer sets and the ddPCR showed higher resilience to PCR inhibitors with citrus leaf and ACP extracts. Hence, the resultant duplex ddPCR assay resulted in a significantly improved detection platform for diagnosis of CLas in samples with low pathogen titer.

Insights into the Structure of Dimeric RNA Helicase CsdA and Indispensable Role of Its C-Terminal Regions.

Science.gov (United States)

Xu, Ling; Wang, Lijun; Peng, Junhui; Li, Fudong; Wu, Lijie; Zhang, Beibei; Lv, Mengqi; Zhang, Jiahai; Gong, Qingguo; Zhang, Rongguang; Zuo, Xiaobing; Zhang, Zhiyong; Wu, Jihui; Tang, Yajun; Shi, Yunyu

2017-12-05

CsdA has been proposed to be essential for the biogenesis of ribosome and gene regulation after cold shock. However, the structure of CsdA and the function of its long C-terminal regions are still unclear. Here, we solved all of the domain structures of CsdA and found two previously uncharacterized auxiliary domains: a dimerization domain (DD) and an RNA-binding domain (RBD). Small-angle X-ray scattering experiments helped to track the conformational flexibilities of the helicase core domains and C-terminal regions. Biochemical assays revealed that DD is indispensable for stabilizing the CsdA dimeric structure. We also demonstrate for the first time that CsdA functions as a stable dimer at low temperature. The C-terminal regions are critical for RNA binding and efficient enzymatic activities. CsdA_RBD could specifically bind to the regions with a preference for single-stranded G-rich RNA, which may help to bring the helicase core to unwind the adjacent duplex. Copyright © 2017 Elsevier Ltd. All rights reserved.

A Simultaneous Analytical Method for Duplex Identification of Porcine and Horse in the Meat Products by EvaGreen based Real-time PCR.

Science.gov (United States)

Sakalar, Ergün; Ergün, Seyma Özçirak; Akar, Emine

2015-01-01

A duplex real-time polymerase chain reaction (PCR) based assay for the detection of porcine and horse meat in sausages was designed by using EvaGreen fluorescent dye. Primers were selected from mitochondrial 12S rRNA and 16S rRNA genes which are powerful regions for identification of horse and porcine meat. DNA from reference samples and industrial products was successfully extracted using the GIDAGEN® Multi-Fast DNA Isolation Kit. Genomes were identified based on their specific melting peaks (Mp) which are 82.5℃ and 78℃ for horse and porcine, respectively. The assay used in this study allowed the detection of as little as 0.0001% level of horse meat and 0.001% level of porcine meat in the experimental admixtures. These findings indicate that EvaGreen based duplex real-time PCR is a potentially sensitive, reliable, rapid and accurate assay for the detection of meat species adulterated with porcine and horse meats.

Joint duplex mode selection, channel allocation, and power control for full-duplex cognitive femtocell networks

Directory of Open Access Journals (Sweden)

Mingjie Feng

2015-02-01

Full Text Available In this paper, we aim to maximize the sum rate of a full-duplex cognitive femtocell network (FDCFN as well as guaranteeing the quality of service (QoS of users in the form of a required signal to interference plus noise ratios (SINR. We first consider the case of a pair of channels, and develop optimum-achieving power control solutions. Then, for the case of multiple channels, we formulate joint duplex model selection, power control, and channel allocation as a mixed integer nonlinear problem (MINLP, and propose an iterative framework to solve it. The proposed iterative framework consists of a duplex mode selection scheme, a near-optimal distributed power control algorithm, and a greedy channel allocation algorithm. We prove the convergence of the proposed iterative framework as well as a lower bound for the greedy channel allocation algorithm. Numerical results show that the proposed schemes effectively improve the sum rate of FDCFNs.

Improper Signaling for Virtual Full-Duplex Relay Systems

KAUST Repository

Gaafar, Mohamed; Amin, Osama; Schaefer, Rafael F.; Alouini, Mohamed-Slim

2017-01-01

Virtual full-duplex (VFD) is a powerful solution to compensate the rate loss of half-duplex relaying without the need to full-duplex capable nodes. Inter-relay interference (IRI) challenges the operation of VFD relaying systems. Recently, improper signaling is employed at both relays of the VFD to mitigate the IRI by imposing the same signal characteristics for both relays. To further boost the achievable rate performance, asymmetric time sharing VFD relaying system is adopted with different improper signals at the half-duplex relays. The joint tuning of the three design parameters improves the achievable rate performance at different ranges of IRI and different relays locations. Extensive simulation results are presented and analyzed to show the achievable rate gain of the proposed system and understand the system behavior.

Improper Signaling for Virtual Full-Duplex Relay Systems

KAUST Repository

Gaafar, Mohamed

2017-02-14

Virtual full-duplex (VFD) is a powerful solution to compensate the rate loss of half-duplex relaying without the need to full-duplex capable nodes. Inter-relay interference (IRI) challenges the operation of VFD relaying systems. Recently, improper signaling is employed at both relays of the VFD to mitigate the IRI by imposing the same signal characteristics for both relays. To further boost the achievable rate performance, asymmetric time sharing VFD relaying system is adopted with different improper signals at the half-duplex relays. The joint tuning of the three design parameters improves the achievable rate performance at different ranges of IRI and different relays locations. Extensive simulation results are presented and analyzed to show the achievable rate gain of the proposed system and understand the system behavior.

Slicer-independent mechanism drives small-RNA strand separation during human RISC assembly.

Science.gov (United States)

Park, June Hyun; Shin, Chanseok

2015-10-30

Small RNA silencing is mediated by the effector RNA-induced silencing complex (RISC) that consists of an Argonaute protein (AGOs 1-4 in humans). A fundamental step during RISC assembly involves the separation of two strands of a small RNA duplex, whereby only the guide strand is retained to form the mature RISC, a process not well understood. Despite the widely accepted view that 'slicer-dependent unwinding' via passenger-strand cleavage is a prerequisite for the assembly of a highly complementary siRNA into the AGO2-RISC, here we show by careful re-examination that 'slicer-independent unwinding' plays a more significant role in human RISC maturation than previously appreciated, not only for a miRNA duplex, but, unexpectedly, for a highly complementary siRNA as well. We discovered that 'slicer-dependency' for the unwinding was affected primarily by certain parameters such as temperature and Mg(2+). We further validate these observations in non-slicer AGOs (1, 3 and 4) that can be programmed with siRNAs at the physiological temperature of humans, suggesting that slicer-independent mechanism is likely a common feature of human AGOs. Our results now clearly explain why both miRNA and siRNA are found in all four human AGOs, which is in striking contrast to the strict small-RNA sorting system in Drosophila. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

Ultra-short silicon MMI duplexer

Science.gov (United States)

Yi, Huaxiang; Huang, Yawen; Wang, Xingjun; Zhou, Zhiping

2012-11-01

The fiber-to-the-home (FTTH) systems are growing fast these days, where two different wavelengths are used for upstream and downstream traffic, typically 1310nm and 1490nm. The duplexers are the key elements to separate these wavelengths into different path in central offices (CO) and optical network unit (ONU) in passive optical network (PON). Multimode interference (MMI) has some benefits to be a duplexer including large fabrication tolerance, low-temperature dependence, and low-polarization dependence, but its size is too large to integrate in conventional case. Based on the silicon photonics platform, ultra-short silicon MMI duplexer was demonstrated to separate the 1310nm and 1490nm lights. By studying the theory of self-image phenomena in MMI, the first order images are adopted in order to keep the device short. A cascaded MMI structure was investigated to implement the wavelength splitting, where both the light of 1310nm and 1490nm was input from the same port, and the 1490nm light was coupling cross the first MMI and output at the cross-port in the device while the 1310nm light was coupling through the first and second MMI and output at the bar-port in the device. The experiment was carried on with the SOI wafer of 340nm top silicon. The cascaded MMI was investigated to fold the length of the duplexer as short as 117μm with the extinct ratio over 10dB.

Kinetics of spontaneous displacement of RNA from heteroduplexes by DNA.

OpenAIRE

Landgraf, R; Ramamurthi, K S; Sigman, D S

1996-01-01

We have used R-loop formation and direct hybridization techniques to analyze the kinetics by which RNA is displaced from a heteroduplex by DNA of identical sequence. Using random walk simulations we were able to calculate the step times for a single displacement reaction. For RNA with a GC content of 57-60% the data indicate an RNA exchange probability of 50.06%, which is indicative of a modest destabilization of the heteroduplex compared with a DNA duplex in the presence of magnesium. The av...

Thermal Stability of siRNA Modulates Aptamer- conjugated siRNA Inhibition

Directory of Open Access Journals (Sweden)

Alexey Berezhnoy

2012-01-01

Full Text Available Oligonucleotide aptamer-mediated in vivo cell targeting of small interfering RNAs (siRNAs is emerging as a useful approach to enhance the efficacy and reduce the adverse effects resulting from siRNA-mediated genetic interference. A current main impediment in aptamer-mediated siRNA targeting is that the activity of the siRNA is often compromised when conjugated to an aptamer, often requiring labor intensive and time consuming design and testing of multiple configurations to identify a conjugate in which the siRNA activity has not been significantly reduced. Here, we show that the thermal stability of the siRNA is an important parameter of siRNA activity in its conjugated form, and that siRNAs with lower melting temperature (Tm are not or are minimally affected when conjugated to the 3′ end of 2′F-pyrimidine-modified aptamers. In addition, the configuration of the aptamer-siRNA conjugate retains activity comparable with the free siRNA duplex when the passenger strand is co-transcribed with the aptamer and 3′ overhangs on the passenger strand are removed. The approach described in this paper significantly reduces the time and effort necessary to screening siRNA sequences that retain biological activity upon aptamer conjugation, facilitating the process of identifying candidate aptamer-siRNA conjugates suitable for in vivo testing.

Development of duplex real-time RT-PCR based on Taqman technology for detecting simultaneously the genome of pan-enterovirus and enterovirus 71.

Science.gov (United States)

Hwang, Seoyeon; Kang, Byunghak; Hong, Jiyoung; Kim, Ahyoun; Kim, Hyejin; Kim, Kisang; Cheon, Doo-Sung

2013-07-01

Human enterovirus (EV) 71 is the main etiological agent of hand, foot, and mouth disease (HFMD). It is associated with neurological complications, and caused fatalities during recent outbreaks in the Asia-Pacific region. Infections caused by EV71 could lead to many complications, ranging from brainstem encephalitis to pulmonary oedema, resulting in high mortality. In this study, a duplex real-time RT-PCR assay was developed in order to simultaneously detect pan-EV and EV71. EV71-specific primers and probes were designed based on the highly conserved VP1 region of EV71. Five EV71 strains were detected as positive, and no positive fluorescence signal was observed in the duplex real-time RT-PCR for other viral RNA, which showed 100% specificity for the selected panel, and no cross-reactions were observed in this duplex real-time RT-PCR. The EV71-specific duplex real-time RT-PCR was more sensitive than conventional RT-PCR, and detected viral titers that were 10-fold lower than those measured by the latter. Of the 381 HFMD clinical specimens, 196 (51.4%) cases were pan-EV-positive, of which 170 (86.7%) were EV71-positive when tested by pan-EV and EV71-specific duplex real-time RT-PCR. EV71-specific duplex real-time RT-PCR offers a rapid and sensitive method to detect EV71 from clinical specimens, and will allow quarantine measures to be taken more effectively during outbreaks. Copyright © 2013 Wiley Periodicals, Inc.

Full-duplex optical communication system

Science.gov (United States)

Shay, Thomas M. (Inventor); Hazzard, David A. (Inventor); Horan, Stephen (Inventor); Payne, Jason A. (Inventor)

2004-01-01

A method of full-duplex electromagnetic communication wherein a pair of data modulation formats are selected for the forward and return data links respectively such that the forward data electro-magnetic beam serves as a carrier for the return data. A method of encoding optical information is used wherein right-hand and left-hand circular polarizations are assigned to optical information to represent binary states. An application for an earth to low earth orbit optical communications system is presented which implements the full-duplex communication and circular polarization keying modulation format.

Precipitation of Chromium Nitrides in the Super Duplex Stainless Steel 2507

Science.gov (United States)

Pettersson, Niklas; Pettersson, Rachel F. A.; Wessman, Sten

2015-03-01

Precipitation of chromium nitrides during cooling from temperatures in the range 1373 K to 1523 K (1100 °C to 1250 °C) has been studied for the super duplex stainless steel 2507 (UNS S32750). Characterization with optical, scanning and transmission electron microscopy was combined to quantify the precipitation process. Primarily Cr2N nitrides were found to precipitate with a high density in the interior of ferrite grains. An increased cooling rate and/or an increased austenite spacing clearly promoted nitride formation, resulting in precipitation within a higher fraction of the ferrite grains, and lager nitride particles. Furthermore, formation of the meta-stable CrN was induced by higher cooling rates. The toughness seemed unaffected by nitrides. A slight decrease in pitting resistance was, however, noticed for quenched samples with large amounts of precipitates. The limited adverse effect on pitting resistance is attributed to the small size (~200 nm) of most nitrides. Slower cooling of duplex stainless steels to allow nitrogen partitioning is suggested in order to avoid large nitrides, and thereby produce a size distribution with a smaller detrimental effect on pitting resistance.

The role of duplex stainless steels for downhole tubulars

International Nuclear Information System (INIS)

Francis, R.

1993-01-01

In sour conditions there is an increasing trend to turn to corrosion resistant alloys for downhole tubulars. The most commonly used CRA tubular is 13Cr, and there are thousands of feet in service. However, there are limits to the use of 13Cr, ie., the risk of sulphide stress corrosion cracking at high H 2 S levels, and the possibility of pitting or high corrosion rates in waters with high chloride contents. Where the service conditions are felt to be too severe for 13Cr alloys it has been traditional to switch to nickel base alloys such as alloys 825 and C-276 (UNS N08825 and N10276). The alloys are much more expensive than 13Cr, and in recent years the duplex stainless steels have been selected as alloys with superior corrosion and SSCC resistance compared with 13Cr, and having lower cost than nickel alloys. Originally the 22Cr duplex alloy (UNS 31803) was used, but more recently the 25Cr super duplex alloys (UNS S32760 and S32750) have become more available. The present paper reviews the data available for 13Cr and the limits of applicability. Data is also presented for laboratory tests for both the 22Cr and 25Cr super duplex alloys. There is extensive service experience with both 22Cr and 25Cr super duplex in the North Sea, covering both downhole tubulars, manifold and post wellhead equipment. Data is presented showing some of the sour condition being experienced in the North Sea by super duplex alloys. These results show that there is a substantial gap between the limits of use for 13Cr and the 25Cr super duplex stainless steel alloys. This means that in many sour environments super duplex stainless steel provides a cost effective alternative to nickel-base alloys

Transcranial Duplex Sonography Predicts Outcome following an Intracerebral Hemorrhage.

Science.gov (United States)

Camps-Renom, P; Méndez, J; Granell, E; Casoni, F; Prats-Sánchez, L; Martínez-Domeño, A; Guisado-Alonso, D; Martí-Fàbregas, J; Delgado-Mederos, R

2017-08-01

Several radiologic features such as hematoma volume are related to poor outcome following an intracerebral hemorrhage and can be measured with transcranial duplex sonography. We sought to determine the prognostic value of transcranial duplex sonography in patients with intracerebral hemorrhage. We conducted a prospective study of patients diagnosed with spontaneous intracerebral hemorrhage. Transcranial duplex sonography examinations were performed within 2 hours of baseline CT, and we recorded the following variables: hematoma volume, midline shift, third ventricle and lateral ventricle diameters, and the pulsatility index in both MCAs. We correlated these data with the CT scans and assessed the prognostic value of the transcranial duplex sonography measurements. We assessed early neurologic deterioration during hospitalization and mortality at 1-month follow-up. We included 35 patients with a mean age of 72.2 ± 12.8 years. Median baseline hematoma volume was 9.85 mL (interquartile range, 2.74-68.29 mL). We found good agreement and excellent correlation between transcranial duplex sonography and CT when measuring hematoma volume ( r = 0.791; P duplex sonography measurements showed that hematoma volume was an independent predictor of early neurologic deterioration (OR, 1.078; 95% CI, 1.023-1.135) and mortality (OR, 1.089; 95% CI, 1.020-1.160). A second regression analysis with CT variables also demonstrated that hematoma volume was associated with early neurologic deterioration and mortality. When we compared the rating operation curves of both models, their predictive power was similar. Transcranial duplex sonography showed an excellent correlation with CT in assessing hematoma volume and midline shift in patients with intracerebral hemorrhage. Hematoma volume measured with transcranial duplex sonography was an independent predictor of poor outcome. © 2017 by American Journal of Neuroradiology.

Crystallization and X-ray diffraction analysis of an ‘all-locked’ nucleic acid duplex derived from a tRNASer microhelix

International Nuclear Information System (INIS)

Behling, Katja; Eichert, André; Fürste, Jens P.; Betzel, Christian; Erdmann, Volker A.; Förster, Charlotte

2009-01-01

A completely ‘all-locked’ nucleic acid duplex was designed from an E. coli tRNA Ser microhelix. The helix consists exclusively of LNA building blocks and was crystallized. The crystals diffracted to 1.9 Å resolution. Modified nucleic acids are of great interest with respect to their nuclease resistance and enhanced thermostability. In therapeutical and diagnostic applications, such molecules can substitute for labile natural nucleic acids that are targeted against particular diseases or applied in gene therapy. The so-called ‘locked nucleic acids’ contain modified sugar moieties such as 2′-O,4′-C-methylene-bridged β-d-ribofuranose and are known to be very stable nucleic acid derivatives. The structure of locked nucleic acids in single or multiple LNA-substituted natural nucleic acids and in LNA–DNA or LNA–RNA heteroduplexes has been well investigated, but the X-ray structure of an ‘all-locked’ nucleic acid double helix has not been described to date. Here, the crystallization and X-ray diffraction data analysis of an ‘all-locked’ nucleic acid helix, which was designed as an LNA originating from a tRNA Ser microhelix RNA structure, is presented. The crystals belonged to space group C2, with unit-cell parameters a = 77.91, b = 40.74, c = 30.06 Å, β = 91.02°. A high-resolution and a low-resolution data set were recorded, with the high-resolution data showing diffraction to 1.9 Å resolution. The crystals contained two double helices per asymmetric unit, with a Matthews coefficient of 2.48 Å 3 Da −1 and a solvent content of 66.49% for the merged data

A most spectrum-efficient duplexing system: CDD

Science.gov (United States)

Lee, William C. Y.

2001-10-01

The game to play in wireless communications when it comes to increasing spectrum efficiency is to eliminate interference. Currently, all cellular systems use FDD (Frequency Division Duplexing) in an attempt to eliminate the interference from the adjacent cells. Through the use of many technologies only one type of interference remains and that is the adjacent base-tohome mobile interference. TDD (Time Division Duplexing) has not been used for mobile cellular systems, not only because of the adjacent base-to-home mobile interference, but also because of the additional adjacent base-to-home base interference, and adjacent mobile-to-home mobile interference. Therefore, TDD can only be used for small, confined area systems. CDD (Code Division Duplexing) can eliminate all three kinds of interference; the adjacent base-to-home mobile, the adjacent baseto-home base, and the adjacent mobile- to- home in cellular systems. Eliminating each of these interferences makes CDD the most spectrum efficient duplexing system. This talk will elaborate on a set of smart codes, which will make an efficient CDD system a reality.

A ready-to-use duplex qPCR to detect Leishmania infantum DNA in naturally infected dogs.

Science.gov (United States)

Rampazzo, Rita de Cássia Pontello; Solcà, Manuela da Silva; Santos, Liliane Celestino Sales; Pereira, Lais de Novaes; Guedes, José Carlos Oliveira; Veras, Patrícia Sampaio Tavares; Fraga, Deborah Bittencourt Mothé; Krieger, Marco Aurélio; Costa, Alexandre Dias Tavares

2017-11-15

Canine visceral leishmaniasis (CVL) is a systemic disease caused by Leishmania infantum. A precise CVL diagnosis would allow for a faster and more specific treatment. Quantitative PCR (qPCR) is a sensitive and specific technique that can diagnose CVL and also monitor parasite load in the animal during the course of the infection or treatment. The aim of this study was to develop a ready-to-use (gelified and freezer-free) duplex qPCR for the identification of infected animals. We combined a new qPCR protocol that detects the canine 18S rRNA gene with an existing protocol for L. infantum kDNA detection, creating a duplex qPCR. This duplex method was then developed into a ready-to-use format. The performance of the duplex and singleplex reactions were compared in the traditional format (liquid and freezer-stored). Furthermore, the duplex qPCR performance was compared between the ready-to-use and traditional formats. The singleplex and new duplex qPCR exhibited the same detection limit in the traditional format (0.1 parasites/reaction). The ready-to-use format showed a detection limit of 1 parasite/reaction without affecting the reaction efficiency. The performance of the new qPCR protocol in the two formats was assessed using canine tissue samples from 82 dogs in an endemic CVL area that were previously characterized by standard serological and parasitological protocols. Splenic aspirates provided a higher rate of positivity (92.9%) followed by skin (50%) and blood (35.7%). The reported detection limits were observed for all tissues studied. Our results show that the amplification of L. infantum kDNA and canine DNA in a single tube, using either the traditional or ready-to-use format, exhibited the same diagnostic performance as amplification of the parasite kDNA alone. The detection of the host gene strengthens the qPCR results by confirming the presence and quality of DNA in the samples and the absence of polymerase inhibitors. The ready-to-use duplex qPCR format

Reducing duplex examinations in patients with iatrogenic pseudoaneurysms.

Science.gov (United States)

Stone, Patrick A; Aburahma, Ali F; Flaherty, Sarah K

2006-06-01

Ultrasound-guided thrombin injection has become the initial treatment of choice for femoral access-related pseudoaneurysms. Patients typically undergo serial duplex examinations to assess for spontaneous resolution of small iatrogenic pseudoaneurysms (IPSAs) (IPSAs (>2.5 cm). We evaluated the impact of a revised treatment algorithm that includes primary treatment of both small (2.5 cm), rather than observation of smaller ones, and attempts to establish a single duplex examination via a point-of-care treatment strategy. We reviewed 105 consecutive patients treated with ultrasound-guided thrombin injection from July 2001 through September 2004. Patient, IPSAs, characteristics, and treatment methods were examined. The number of duplex examinations per patient was evaluated over the treatment interval. Also, published cost data were used to compare primary treatment of small ISPAs vs observation with serial duplex examinations. Successful thrombosis occurred in 103 (98.1%) of 105 treated pseudoaneurysms. No minor or major complications occurred after thrombin injection in either small or large ISPAs, and both failures requiring operation were in the large aneurysm group. The recurrence rate for the series was 1.9% (2/105), and both recurrences were successfully treated with an additional thrombin injection. A single injection was successful in treating 43 (97.7%) of 44 small (IPSAs, and one required a second injection. Patients had an average of 3.3 duplex examinations in our first year of treatment experience, which declined to 1.5 by our third year with the institution of a point-of-care service model for all pseudoaneurysms. Based on this decreased use of duplex examination and an average treatment cohort of 35 IPSA patients per year our institution, we determined this results in a reduction of 35 hours of laboratory time and nearly 70 ultrasounds per year. Similarly for small pseudoaneurysms, a point-of-service primary treatment program rather than observation

Force-Induced Rupture of a DNA Duplex: From Fundamentals to Force Sensors.

Science.gov (United States)

Mosayebi, Majid; Louis, Ard A; Doye, Jonathan P K; Ouldridge, Thomas E

2015-12-22

The rupture of double-stranded DNA under stress is a key process in biophysics and nanotechnology. In this article, we consider the shear-induced rupture of short DNA duplexes, a system that has been given new importance by recently designed force sensors and nanotechnological devices. We argue that rupture must be understood as an activated process, where the duplex state is metastable and the strands will separate in a finite time that depends on the duplex length and the force applied. Thus, the critical shearing force required to rupture a duplex depends strongly on the time scale of observation. We use simple models of DNA to show that this approach naturally captures the observed dependence of the force required to rupture a duplex within a given time on duplex length. In particular, this critical force is zero for the shortest duplexes, before rising sharply and then plateauing in the long length limit. The prevailing approach, based on identifying when the presence of each additional base pair within the duplex is thermodynamically unfavorable rather than allowing for metastability, does not predict a time-scale-dependent critical force and does not naturally incorporate a critical force of zero for the shortest duplexes. We demonstrate that our findings have important consequences for the behavior of a new force-sensing nanodevice, which operates in a mixed mode that interpolates between shearing and unzipping. At a fixed time scale and duplex length, the critical force exhibits a sigmoidal dependence on the fraction of the duplex that is subject to shearing.

Downlink Error Rates of Half-duplex Users in Full-duplex Networks over a Laplacian Inter-User Interference Limited and EGK fading

KAUST Repository

Soury, Hamza; Elsawy, Hesham; Alouini, Mohamed-Slim

2017-01-01

This paper develops a mathematical framework to study downlink error rates and throughput for half-duplex (HD) terminals served by a full-duplex (FD) base station (BS). The developed model is used to motivate long term pairing for users that have

A Simultaneous Analytical Method for Duplex Identification of Porcine and Horse in the Meat Products by EvaGreen based Real-time PCR

OpenAIRE

Sakalar, Erg?n; Erg?n, Seyma ?z?irak; Akar, Emine

2015-01-01

A duplex real-time polymerase chain reaction (PCR) based assay for the detection of porcine and horse meat in sausages was designed by using EvaGreen fluorescent dye. Primers were selected from mitochondrial 12S rRNA and 16S rRNA genes which are powerful regions for identification of horse and porcine meat. DNA from reference samples and industrial products was successfully extracted using the GIDAGEN? Multi-Fast DNA Isolation Kit. Genomes were identified based on their specific melting peaks...

Capturing a DNA duplex under near-physiological conditions

Science.gov (United States)

Zhang, Huijuan; Xu, Wei; Liu, Xiaogang; Stellacci, Francesco; Thong, John T. L.

2010-10-01

We report in situ trapping of a thiolated DNA duplex with eight base pairs into a polymer-protected gold nanogap device under near-physiological conditions. The double-stranded DNA was captured by electrophoresis and covalently attached to the nanogap electrodes through sulfur-gold bonding interaction. The immobilization of the DNA duplex was confirmed by direct electrical measurements under near-physiological conditions. The conductance of the DNA duplex was estimated to be 0.09 μS. We also demonstrate the control of DNA dehybridization by heating the device to temperatures above the melting point of the DNA.

Duplex unwinding and ATPase activities of the DEAD-box helicase eIF4A are coupled by eIF4G and eIF4B

Science.gov (United States)

Özeş, Ali R.; Feoktistova, Kateryna; Avanzino, Brian C.; Fraser, Christopher S.

2011-01-01

Eukaryotic initiation factor 4A (eIF4A) is a DEAD-box helicase that stimulates translation initiation by unwinding mRNA secondary structure. The accessory proteins, eIF4G, eIF4B, and eIF4H enhance the duplex unwinding activity of eIF4A, but the extent to which they modulate eIF4A activity is poorly understood. Here, we use real time fluorescence assays to determine the kinetic parameters of duplex unwinding and ATP hydrolysis by these initiation factors. To ensure efficient duplex unwinding, eIF4B and eIF4G cooperatively activate the duplex unwinding activity of eIF4A. Our data reveal that eIF4H is much less efficient at stimulating eIF4A unwinding activity than eIF4B, implying that eIF4H is not able to completely substitute for eIF4B in duplex unwinding. By monitoring unwinding and ATPase assays using identical conditions, we demonstrate that eIF4B couples the ATP hydrolysis cycle of eIF4A with strand separation, thereby minimizing non-productive unwinding events. Using duplex substrates with altered GC contents, but with similar predicted thermal stabilities, we further show that the rate of formation of productive unwinding complexes is strongly influenced by the local stability per base pair in addition to the stability of the entire duplex. This finding explains how a change in the GC content of a hairpin while maintaining overall predicted thermal stability is able to influence translation initiation. PMID:21840318

Recognition of DNA/RNA bulges by antimicrobial and antitumor metallohelices

Czech Academy of Sciences Publication Activity Database

Malina, Jaroslav; Scott, P.; Brabec, Viktor

2015-01-01

Roč. 44, č. 33 (2015), s. 14656-14665 ISSN 1477-9226 R&D Projects: GA ČR(CZ) GAP205/11/0856 Institutional support: RVO:68081707 Keywords : CONTAINING DEOXYTRIDECANUCLEOTIDE DUPLEXES * HIV -1 TAR RNA * METALLOSUPRAMOLECULAR CYLINDERS Subject RIV: BO - Biophysics Impact factor: 4.177, year: 2015

Highly stable aptamers selected from a 2'-fully modified fGmH RNA library for targeting biomaterials.

Science.gov (United States)

Friedman, Adam D; Kim, Dongwook; Liu, Rihe

2015-01-01

When developed as targeting ligands for the in vivo delivery of biomaterials to biological systems, RNA aptamers immediately face numerous obstacles, in particular nuclease degradation and post-selection 2' modification. This study aims to develop a novel class of highly stable, 2'-fully modified RNA aptamers that are ideal for the targeted delivery of biomaterials. We demonstrated the facile transcription of a fGmH (2'-F-dG, 2'-OMe-dA/dC/dU) RNA library with unexpected hydrophobicity, the direct selection of aptamers from a fGmH RNA library that bind Staphylococcus aureus Protein A (SpA) as a model target, and the superior nuclease and serum stability of these aptamers compared to 2'-partially modified RNA variants. Characterizations of fGmH RNA aptamers binding to purified SpA and to endogenous SpA present on the surface of S. aureus cells demonstrate fGmH RNA aptamer selectivity and stability. Significantly, fGmH RNA aptamers were able to functionalize, stabilize, and specifically deliver aggregation-prone silver nanoparticles (AgNPs) to S. aureus with SpA-dependent antimicrobial effects. This study describes a novel aptamer class with considerable potential to improve the in vivo applicability of nucleic acid-based affinity molecules to biomaterials.

siRNA and innate immunity.

Science.gov (United States)

Robbins, Marjorie; Judge, Adam; MacLachlan, Ian

2009-06-01

Canonical small interfering RNA (siRNA) duplexes are potent activators of the mammalian innate immune system. The induction of innate immunity by siRNA is dependent on siRNA structure and sequence, method of delivery, and cell type. Synthetic siRNA in delivery vehicles that facilitate cellular uptake can induce high levels of inflammatory cytokines and interferons after systemic administration in mammals and in primary human blood cell cultures. This activation is predominantly mediated by immune cells, normally via a Toll-like receptor (TLR) pathway. The siRNA sequence dependency of these pathways varies with the type and location of the TLR involved. Alternatively nonimmune cell activation may also occur, typically resulting from siRNA interaction with cytoplasmic RNA sensors such as RIG1. As immune activation by siRNA-based drugs represents an undesirable side effect due to the considerable toxicities associated with excessive cytokine release in humans, understanding and abrogating this activity will be a critical component in the development of safe and effective therapeutics. This review describes the intracellular mechanisms of innate immune activation by siRNA, the design of appropriate sequences and chemical modification approaches, and suitable experimental methods for studying their effects, with a view toward reducing siRNA-mediated off-target effects.

Full-duplex wireless communications systems self-interference cancellation

CERN Document Server

Le-Ngoc, Tho

2017-01-01

This book introduces the development of self-interference (SI)-cancellation techniques for full-duplex wireless communication systems. The authors rely on estimation theory and signal processing to develop SI-cancellation algorithms by generating an estimate of the received SI and subtracting it from the received signal. The authors also cover two new SI-cancellation methods using the new concept of active signal injection (ASI) for full-duplex MIMO-OFDM systems. The ASI approach adds an appropriate cancelling signal to each transmitted signal such that the combined signals from transmit antennas attenuate the SI at the receive antennas. The authors illustrate that the SI-pre-cancelling signal does not affect the data-bearing signal. This book is for researchers and professionals working in wireless communications and engineers willing to understand the challenges of deploying full-duplex and practical solutions to implement a full-duplex system. Advanced-level students in electrical engineering and computer ...

Tensile properties of duplex UNS S32205 and lean duplex UNS S32304 steels and the influence of short duration 475 ºC aging

Directory of Open Access Journals (Sweden)

Sérgio Souto Maior Tavares

2012-12-01

Full Text Available Duplex stainless steels are high strength and corrosion resistant steels extensively used in the petrochemical and chemical industries. The aging at 475 ºC for long periods of time provokes embrittlement and deterioration of corrosion resistance. However, short duration aging at 475 ºC may be used as heat treatment to improve mechanical resistance with small decrease in the other properties. In this work the flow stress curves of lean duplex UNS S32304 and duplex UNS S32205 steels were modeled with Hollomon's equation and work hardening exponents (n were determined. The analyses were conducted in specimens annealed and heat treated at 475 ºC for short periods of time. The aging at 475 ºC for 4 hours, 8 hours and 12 hours promoted significant hardening with small decrease of ductility. The work hardening exponents of both steels were compared, being higher in the duplex steel than in the lean duplex grade.

Clinical utility of carotid duplex ultrasound prior to cardiac surgery.

Science.gov (United States)

Lin, Judith C; Kabbani, Loay S; Peterson, Edward L; Masabni, Khalil; Morgan, Jeffrey A; Brooks, Sara; Wertella, Kathleen P; Paone, Gaetano

2016-03-01

Clinical utility and cost-effectiveness of carotid duplex examination prior to cardiac surgery have been questioned by the multidisciplinary committee creating the 2012 Appropriate Use Criteria for Peripheral Vascular Laboratory Testing. We report the clinical outcomes and postoperative neurologic symptoms in patients who underwent carotid duplex ultrasound prior to open heart surgery at a tertiary institution. Using the combined databases from our clinical vascular laboratory and the Society of Thoracic Surgery, a retrospective analysis of all patients who underwent carotid duplex ultrasound within 13 months prior to open heart surgery from March 2005 to March 2013 was performed. The outcomes between those who underwent carotid duplex scanning (group A) and those who did not (group B) were compared. Among 3233 patients in the cohort who underwent cardiac surgery, 515 (15.9%) patients underwent a carotid duplex ultrasound preoperatively, and 2718 patients did not (84.1%). Among the patients who underwent carotid screening vs no screening, there was no statistically significant difference in the risk factors of cerebrovascular disease (10.9% vs 12.7%; P = .26), prior stroke (8.2% vs 7.2%; P = .41), and prior transient ischemic attack (2.9% vs 3.3%; P = .24). For those undergoing isolated coronary artery bypass grafting (CABG), 306 (17.8%) of 1723 patients underwent preoperative carotid duplex ultrasound. Among patients who had carotid screening prior to CABG, the incidence of carotid disease was low: 249 (81.4%) had minimal or mild stenosis (duplex scanning and those who did not. Primary outcomes of patients who underwent open heart surgery also showed no difference in the perioperative mortality (5.1% vs 6.9%; P = .14) and stroke (2.6% vs 2.4%; P = .85) between patients undergoing preoperative duplex scanning and those who did not. Operative intervention of severe carotid stenosis prior to isolated CABG occurred in 2 of the 17 patients (11.8%) identified who

Perancangan dan Implementasi Duplexer Mikrostrip untuk Frekuensi LTE pada band ke-7

Directory of Open Access Journals (Sweden)

ENCENG SULAEMAN

2013-07-01

The necessary of mobile communication has increased in technology, now it released the new of technology is Long Term Evolution (LTE. Type of duplex is Frequency Division Duplex (FDD, designed a duplexer which it is capable for transmitting and receiving process at the same time with the different of frequency between uplink and downlink. Research of designed and implemented a duplexer using Hybrid Coupler and Bandstop filters based on Split Ring Resonators for the frequency band 7th on LTE technology at Base Transceiver Station (BTS. Duplexer is made by combining two coupler and two bandstop filter. The results of duplexer measurements, when Tx port transmit the signal to antenna port with attenuation at the downlink frequency center at 3.168 dB. Attenuation from antenna port to Rx port about 6 dB. Isolation between Tx port and Rx port about 15 dB. Keywords: Duplexer, Bandstop Filter, Split Ring Resonator, Hybrid Coupler, and Long Term Evolution.

Electron Beam Welding of Duplex Steels with using Heat Treatment

Science.gov (United States)

Schwarz, Ladislav; Vrtochová, Tatiana; Ulrich, Koloman

2010-01-01

This contribution presents characteristics, metallurgy and weldability of duplex steels with using concentrated energy source. The first part of the article describes metallurgy of duplex steels and the influence of nitrogen on their solidification. The second part focuses on weldability of duplex steels with using electron beam aimed on acceptable structure and corrosion resistance performed by multiple runs of defocused beam over the penetration weld.

Perancangan dan Implementasi Duplexer Mikrostrip untuk Frekuensi LTE pada band ke-7

Directory of Open Access Journals (Sweden)

ENCENG SULAEMAN

2017-06-01

Full Text Available ABSTRAK Kebutuhan akan komunikasi bergerak semakin mengalami peningkatan dalam dunia teknologi yang ada saat ini, maka hadirlah teknologi terbaru yaitu Long Term Evolution (LTE. Dengan teknik duplex jenis Frequency Division Duplex (FDD, dirancanglah duplexer yang mampu melakukan proses pengiriman dan penerimaan dalam satu waktu dengan frekuensi yang berbeda antara uplink dan downlink. Pada penelitian ini dirancang dan diimplementasikan sebuah duplekser dengan menggunakan metoda Hybrid Coupler dan Bandstop Filter berbasis Split Ring Resonator untuk band frekuensi ke-7 pada teknologi LTE di sisi Base Transceiver Station (BTS. Duplekser dibuat dengan menggabungkan dua buah hybrid Coupler dan dua buah Bandstop Filter. Hasil pengukuran duplexer saat port Tx mengirimkan sinyal ke antena dengan nilai redaman pada frekuensi tengah downlink sebesar 3.168 dB. Lalu pada saat antena menerima sinyal untuk diteruskan ke Rx terdapat redaman di frekuensi tengah uplink sebesar 6 dB. Sedangkan untuk isolasi dari port Tx-port Rx dihasilkan sebesar 15 dB. Kata kunci: Duplexer, Bandstop Filter, Split Ring Resonator, Hybrid Coupler, dan Long Term Evolution. ABSTRACT The necessary of mobile communication has increased in technology, now it released the new of technology is Long Term Evolution (LTE. Type of duplex is Frequency Division Duplex (FDD, designed a duplexer which it is capable for transmitting and receiving process at the same time with the different of frequency between uplink and downlink. Research of designed and implemented a duplexer using Hybrid Coupler and Bandstop filters based on Split Ring Resonators for the frequency band 7th on LTE technology at Base Transceiver Station (BTS. Duplexer is made by combining two coupler and two bandstop filter. The results of duplexer measurements, when Tx port transmit the signal to antenna port with attenuation at the downlink frequency center at 3.168 dB. Attenuation from antenna port to Rx port about 6 d

Development of a duplex real-time RT-qPCR assay to monitor genome replication, gene expression and gene insert stability during in vivo replication of a prototype live attenuated canine distemper virus vector encoding SIV gag.

Science.gov (United States)

Coleman, John W; Wright, Kevin J; Wallace, Olivia L; Sharma, Palka; Arendt, Heather; Martinez, Jennifer; DeStefano, Joanne; Zamb, Timothy P; Zhang, Xinsheng; Parks, Christopher L

2015-03-01

Advancement of new vaccines based on live viral vectors requires sensitive assays to analyze in vivo replication, gene expression and genetic stability. In this study, attenuated canine distemper virus (CDV) was used as a vaccine delivery vector and duplex 2-step quantitative real-time RT-PCR (RT-qPCR) assays specific for genomic RNA (gRNA) or mRNA have been developed that concurrently quantify coding sequences for the CDV nucleocapsid protein (N) and a foreign vaccine antigen (SIV Gag). These amplicons, which had detection limits of about 10 copies per PCR reaction, were used to show that abdominal cavity lymphoid tissues were a primary site of CDV vector replication in infected ferrets, and importantly, CDV gRNA or mRNA was undetectable in brain tissue. In addition, the gRNA duplex assay was adapted for monitoring foreign gene insert genetic stability during in vivo replication by analyzing the ratio of CDV N and SIV gag genomic RNA copies over the course of vector infection. This measurement was found to be a sensitive probe for assessing the in vivo genetic stability of the foreign gene insert. Copyright © 2014 Elsevier B.V. All rights reserved.

The Duplex Society.

Science.gov (United States)

Schorr, Alvin L.

1984-01-01

The duplex society, in which the poor live in close proximity to others but in a separate compartment, is already with us. Unless something deeply changes about family income, more than one-third of future generations will come to adulthood having spent a portion of their childhood in official poverty. (RM)

On the Performance of In-Band Full-Duplex Cooperative Communications

KAUST Repository

Khafagy, Mohammad Galal

2016-06-01

In-band full-duplex, by which radios may simultaneously transmit and receive over the same channel, has been always considered practically-unfeasible due to the prohibitively strong self-interference. Indeed, a freshly-generated transmit signal power is typically ten orders of magnitude higher than that of a naturally-attenuated received signal. While unable to manage such an overwhelming interference, wireless communications resorted to half-duplex operation, transmitting and receiving over orthogonal channel resources. Recent research has demonstrated the practical feasibility of full-duplexing via successive sophisticated stages of signal suppression/cancellation, bringing this long-held assumption down and reviving the promising full-duplex potentials. Full-duplex relaying (FDR), where intermediate nodes may now support source-destination communication via simultaneous listening/forwarding, represents one of two full-duplex settings currently recommended for deployment in future fifth-generation (5G) systems. Theoretically, it has been widely accepted that FDR potentially doubles the channel capacity when compared to its half-duplex counterpart. Although FDR doubles the multiplexing gain, the effective signal-to-noise ratio (SNR) can be significantly degraded due to the residual self-interference (RSI) if not properly handled. In this work, efficient protocols are devised for different FDR settings. Selective cooperation is proposed for the canonical three-terminal FDR channel with RSI, which exploits the cooperative diversity offered by the independently fading source/relay message replicas arriving at the destination. Closed-form expressions are derived for the end-to-end SNR cumulative distribution function (CDF) under Rayleigh and Nakagami-m fading. Further, the offered diversity gain is presented as a function of the RSI scaling trend with the relay power. We show that the existing diversity problem in simple FDR protocols can be considerably fixed via

On full duplex Gaussian relay channels with self-interference

KAUST Repository

Behboodi, Arash; Chaaban, Anas; Mathar, Rudolf; Alouini, Mohamed-Slim

2016-01-01

Self interference (SI) in full duplex (FD) systems is the interference caused by the transmission stream on the reception stream. Being one of the main restrictive factors for performance of practical full duplex systems, however, not too much

Optimization of welding variables for duplex stainless steel by GTAW and SMAW

International Nuclear Information System (INIS)

Ajmal, M.; Anwar, M.Y.; Nawaz, A.

2006-01-01

The main problems faced during the welding of duplex stainless steels are cleanliness and slag inclusions. In the present work the methods to eliminate these problems were studied during the welding of duplex stainless steel by Gas Tungsten Arc Welding (GTAW) and Shielded Metal Arc Welding (SMAW). Since the duplex stainless steel is an expensive material, the initial experiments for optimization of welding variables were. carried out on low carbon steel (CS) plates with duplex consumables. Welding of butt groove joints on CS plates was carried with various sets of welding variables i.e. current, voltage and arc energy using duplex consumables. The. radiographic inspection, micro-structural observations and hardness testing of the welds suggested the welding variables that will produce a sound weld on CS plate. These optimized variables were then used for the welding of edge groove joint and T -joint on duplex stainless steel by GTAW and SMAW processes. The hardness and micro-structural study of the joints produced on duplex stainless steel by GTAW and SMAW with duplex consumables were also studied. No slag inclusions and porosity were observed in the microstructure of these weldments and their properties were found similar to the parent metal. (author)

Duplex/quadruplex oligonucleotides: Role of the duplex domain in the stabilization of a new generation of highly effective anti-thrombin aptamers.

Science.gov (United States)

Russo Krauss, Irene; Napolitano, Valeria; Petraccone, Luigi; Troisi, Romualdo; Spiridonova, Vera; Mattia, Carlo Andrea; Sica, Filomena

2018-02-01

Recently, mixed duplex/quadruplex oligonucleotides have attracted great interest for use as biomedical aptamers. In the case of anti-thrombin aptamers, the addition of duplex-forming sequences to a G-quadruplex module identical or very similar to the best-known G-quadruplex of the Thrombin Binding Aptamer (HD1) results in new or improved biological properties, such as higher activity or different recognition properties with respect to HD1. Remarkably, this bimodular fold was hypothesized, based on its sequence, for the only anti-thrombin aptamer in advanced clinical trial, NU172. Whereas cation modulation of G-quadruplex conformation and stability is well characterized, only few data from similar analysis on duplex/quadruplex oligonucleotides exist. Here we have performed a characterization of structure and stability of four different duplex/quadruplex anti-thrombin aptamers, including NU172, in the presence of different cations and in physiological-mimicking conditions in comparison to HD1, by means of spectroscopic techniques (UV and circular dichroism) and differential scanning calorimetry. Our data show a strong reciprocal influence of each domain on the stability of the other and in particular suggest a stabilizing effect of the duplex region in the presence of solutions mimicking the physiological conditions, strengthening the idea that bimodular aptamers present better therapeutic potentialities than those containing a single G-quadruplex domain. Copyright © 2017 Elsevier B.V. All rights reserved.

Weldability aspects of a newly developed duplex stainless steel LDX 2101

Energy Technology Data Exchange (ETDEWEB)

Westin, E.M. [Avesta Research Centre, Avesta (Sweden). Outokumpu Stainless; Brolund, B. [SSAB Tunnplat, Borlaenge (Sweden); Hertzman, S. [Outokumpu Stainless Research Foundation, Stockholm (Sweden)

2008-06-15

Duplex grades have, due to balanced chemical compositions of both filler and base metals, a weldability that allows for successful welding using a majority of the technically relevant techniques of today. In order to fulfil the performance requirements several aspects must be considered. In the heat affected zone (HAZ) the austenite reformation must be reasonably high and in the weld metal the microstructure must be stable so that e.g. high productivity welding and multi-pass welding are possible, without precipitation of detrimental phases in previous passes. This paper addresses the effect of alloying elements and thermal cycles on phase balance in the high temperature HAZ (HTHAZ) of the newly developed lean duplex grade LDX 2101 (EN 1.4162, UNS S32101). Bead-on-plate welds and simulated weld structures have been produced and investigated using metallography, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results are analysed using the thermodynamic database Thermo-Calc and a model for phase transformation based on a paraequilibrium assumption for ferrite-austenite transformation. In the temperature region outside the paraequilibrium domain, growth controlled by diffusion of substitutional elements was considered. The analysis follows a model by Cahn regarding grain boundary nucleated growth and the Hillert-Engberg model on kinetics of spherical and planar growth. (orig.)

Linking phylogenetic identities of bacteria to starch fermentation in an in vitro model of the large intestine by RNA-based stable isotope probing

NARCIS (Netherlands)

Kovatcheva-Datchary, P.; Egert, M.; Maathuis, A.; Rajilić-Stojanović, M.; Graaf, A.A.de; Smidt, H.; Vos, W.M.de; Venema, K.

2009-01-01

Summary Carbohydrates, including starches, are an important energy source for humans, and are known for their interactions with the microbiota in the digestive tract. Largely, those interactions are thought to promote human health. Using 16S ribosomal RNA (rRNA)-based stable isotope probing (SIP),

EFFECT OF INTERMETALLIC PHASES ON CORROSION BEHAVIOR AND MECHANICAL PROPERTIES OF DUPLEX STAINLESS STEEL AND SUPER-DUPLEX STAINLESS STEEL

OpenAIRE

Prabhu Paulraj; Rajnish Garg

2015-01-01

Duplex Stainless Steels (DSS) and Super Duplex Stainless Steel (SDSS) have excellent integration of mechanical and corrosion properties. However, the formation of intermetallic phases is a major problem in their usage. The mechanical and corrosion properties are deteriorated due to the presence of intermetallic phases. These phases are induced during welding, prolonged exposure to high temperatures, and improper heat treatments. The main emphasis of this review article is on intermetallic pha...

Binding modes and pathway of RHPS4 to human telomeric G-quadruplex and duplex DNA probed by all-atom molecular dynamics simulations with explicit solvent.

Science.gov (United States)

Mulholland, Kelly; Siddiquei, Farzana; Wu, Chun

2017-07-19

RHPS4, a potent binder to human telomeric DNA G-quadruplex, shows high efficacy in tumor cell growth inhibition. However, it's preferential binding to DNA G-quadruplex over DNA duplex (about 10 fold) remains to be improved toward its clinical application. A high resolution structure of the single-stranded telomeric DNA G-quadruplexes, or B-DNA duplex, in complex with RHPS4 is not available yet, and the binding nature of this ligand to these DNA forms remains to be elusive. In this study, we carried out 40 μs molecular dynamics binding simulations with a free ligand to decipher the binding pathway of RHPS4 to a DNA duplex and three G-quadruplex folders (parallel, antiparallel and hybrid) of the human telomeric DNA sequence. The most stable binding mode identified for the duplex, parallel, antiparallel and hybrid G-quadruplexes is an intercalation, bottom stacking, top intercalation and bottom intercalation mode, respectively. The intercalation mode with similar binding strength to both the duplex and the G-quadruplexes, explains the lack of binding selectivity of RHPS4 to the G-quadruplex form. Therefore, a ligand modification that destabilizes the duplex intercalation mode but stabilizes the G-quadruplex intercalation mode will improve the binding selectivity toward G-quadruplex. The intercalation mode of RHPS4 to both the duplex and the antiparallel and the hybrid G-quadruplex follows a base flipping-insertion mechanism rather than an open-insertion mechanism. The groove binding, the side binding and the intercalation with flipping out of base were observed to be intermediate states before the full intercalation state with paired bases.

Water-evaporation reduction by duplex films: application to the human tear film.

Science.gov (United States)

Cerretani, Colin F; Ho, Nghia H; Radke, C J

2013-09-01

Water-evaporation reduction by duplex-oil films is especially important to understand the physiology of the human tear film. Secreted lipids, called meibum, form a duplex film that coats the aqueous tear film and purportedly reduces tear evaporation. Lipid-layer deficiency is correlated with the occurrence of dry-eye disease; however, in-vitro experiments fail to show water-evaporation reduction by tear-lipid duplex films. We review the available literature on water-evaporation reduction by duplex-oil films and outline the theoretical underpinnings of spreading and evaporation kinetics that govern behavior of these systems. A dissolution-diffusion model unifies the data reported in the literature and identifies dewetting of duplex films into lenses as a key challenge to obtaining significant evaporation reduction. We develop an improved apparatus for measuring evaporation reduction by duplex-oil films including simultaneous assessment of film coverage, stability, and temperature, all under controlled external mass transfer. New data reported in this study fit into the larger body of work conducted on water-evaporation reduction by duplex-oil films. Duplex-oil films of oxidized mineral oil/mucin (MOx/BSM), human meibum (HM), and bovine meibum (BM) reduce water evaporation by a dissolution-diffusion mechanism, as confirmed by agreement between measurement and theory. The water permeability of oxidized-mineral-oil duplex films agrees with those reported in the literature, after correction for the presence of mucin. We find that duplex-oil films of bovine and human meibum at physiologic temperature reduce water evaporation only 6-8% for a 100-nm film thickness pertinent to the human tear film. Comparison to in-vivo human tear-evaporation measurements is inconclusive because evaporation from a clean-water surface is not measured and because the mass-transfer resistance is not characterized. Copyright © 2013 Elsevier B.V. All rights reserved.

Response of duplex Cr(N)/S and Cr(C)/S coatings on 316L stainless steel to tribocorrosion in 0.89% NaCl solution under plastic contact conditions.

Science.gov (United States)

Sun, Y; Dearnley, P A; Mallia, Bertram

2017-08-01

Two duplex coatings, Cr(N)/S and Cr(C)/S, were deposited on 316 L stainless steel by magnetron sputtering. The effectiveness of these duplex coatings in improving the tribocorrosion behavior of medical alloys under elastic contact conditions has been demonstrated in a recent publication. The present work focused on the response of these duplex coatings to tribocorrosion under plastic contact conditions. Tribocorrosion tests were conducted in 0.89% NaCl solution at 37°C at an initial contact pressure of 740 MPa and under unidirectional sliding conditions for sliding duration up to 24 h. The results showed that during sliding in the corrosive solution, the duplex coatings were plastically deformed into the substrate to a depth about 1 μm. The Cr(C)/S duplex coating had sufficient ductility to accommodate the deformation without cracking, such that it was worn through gradually, leading to the gradual increase in open circuit potential (OCP) and coefficient of friction (COF). On the other hand, the Cr(N)/S duplex coating suffered from cracking at all tested potentials, leading to coating blistering after prolonged sliding at OCP and stable pit formation in the substrate beneath the coating at applied anodic potentials. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1503-1513, 2017. © 2016 Wiley Periodicals, Inc.

Physical-Layer Security of a Buffer-Aided Full-Duplex Relaying System

KAUST Repository

El Shafie, Ahmed

2016-07-07

This letter proposes a novel hybrid half-/full-duplex relaying scheme to enhance the relay channel security. A source node (Alice) communicates with her destination node (Bob) in the presence of a buffer-aided full-duplex relay node (Rooney) and a potential eavesdropper (Eve). Rooney adopts two different relaying, namely randomize-and-forward and decode-andforward relaying strategies, to improve the security of the legitimate system. In the first relaying strategy, Rooney uses a codebook different from that used at Alice. In the second relaying strategy, Rooney and Alice use the same codebooks. In addition, Rooney switches between half-duplex and full-duplex modes to further enhance the security of the legitimate system. The numerical results demonstrate that our proposed scheme achieves a significant average secrecy end-to-end throughput improvement relative to the conventional bufferless full-duplex relaying scheme.

Physical-Layer Security of a Buffer-Aided Full-Duplex Relaying System

KAUST Repository

El Shafie, Ahmed; Salem, Ahmed Sultan; Al-Dhahir, Naofal

2016-01-01

This letter proposes a novel hybrid half-/full-duplex relaying scheme to enhance the relay channel security. A source node (Alice) communicates with her destination node (Bob) in the presence of a buffer-aided full-duplex relay node (Rooney) and a potential eavesdropper (Eve). Rooney adopts two different relaying, namely randomize-and-forward and decode-andforward relaying strategies, to improve the security of the legitimate system. In the first relaying strategy, Rooney uses a codebook different from that used at Alice. In the second relaying strategy, Rooney and Alice use the same codebooks. In addition, Rooney switches between half-duplex and full-duplex modes to further enhance the security of the legitimate system. The numerical results demonstrate that our proposed scheme achieves a significant average secrecy end-to-end throughput improvement relative to the conventional bufferless full-duplex relaying scheme.

Characterization of thermal aging of duplex stainless steel by SQUID

International Nuclear Information System (INIS)

Isobe, Y.; Kamimura, A.; Aoki, K.; Nakayasu, F.

1995-01-01

Thermal aging is a growing concern for long-term-aged duplex stainless steel piping in nuclear power plants. Superconducting QUantum Interference Device (SQUID) was used for the detection of thermal aging of SUS329 rolled duplex stainless steel and SCS16 cast duplex stainless steel. It was found that the SQUID output signal pattern in the presence of AC magnetic field applied to the specimen was sensitive to the changes in electromagnetic properties due to thermal aging

Plant MicroRNA Prediction by Supervised Machine Learning Using C5.0 Decision Trees.

Science.gov (United States)

Williams, Philip H; Eyles, Rod; Weiller, Georg

2012-01-01

MicroRNAs (miRNAs) are nonprotein coding RNAs between 20 and 22 nucleotides long that attenuate protein production. Different types of sequence data are being investigated for novel miRNAs, including genomic and transcriptomic sequences. A variety of machine learning methods have successfully predicted miRNA precursors, mature miRNAs, and other nonprotein coding sequences. MirTools, mirDeep2, and miRanalyzer require "read count" to be included with the input sequences, which restricts their use to deep-sequencing data. Our aim was to train a predictor using a cross-section of different species to accurately predict miRNAs outside the training set. We wanted a system that did not require read-count for prediction and could therefore be applied to short sequences extracted from genomic, EST, or RNA-seq sources. A miRNA-predictive decision-tree model has been developed by supervised machine learning. It only requires that the corresponding genome or transcriptome is available within a sequence window that includes the precursor candidate so that the required sequence features can be collected. Some of the most critical features for training the predictor are the miRNA:miRNA(∗) duplex energy and the number of mismatches in the duplex. We present a cross-species plant miRNA predictor with 84.08% sensitivity and 98.53% specificity based on rigorous testing by leave-one-out validation.

NMR studies of abasic sites in DNA duplexes: deoxyadenosine stacks into the helix opposite the cyclic analog of 2-deoxyribose

International Nuclear Information System (INIS)

Kalnik, M.W.; Chang, C.N.; Grollman, A.P.; Patel, D.J.

1988-01-01

Proton and phosphorus NMR studies are reported for the complementary d(C-A-T-G-A-G-T-A-C) x d(G-T-A-C-F-C-A-T-G) nonanucleotide duplex (designated AP/sub F/ 9-mer duplex) which contains a stable abasic site analog, F, in the center of the helix. This oligodeoxynucleotide contains a modified tetrahydrofuran moiety, isosteric with 2-deoxyribofuranose, which serves as a structural analog of a natural apurinic/apyrimidinic site. Exchangeable and nonexchangeable base and sugar protons, including those located at the abasic site, have been assigned in the complementary AP/sub F/ 9-mer duplex by recording and analyzing two-dimensional phase-sensitive NOESY data sets in H 2 O and D 2 O solution at low temperature (0 0 C). These studies indicate that A5 inserts into the helix opposite the abasic site F14 and stacks with flanking G4 x C15 and G6 x C13 Watson-Crick base pairs. Base-sugar proton NOE connectivities were measured through G4-A5-G6 on the unmodified strand and between the base protons of C15 and the sugar protons of the 5'-flanking residue F14 on the modified strand. These studies establish that all glycosidic torsion angles are anti and that the helix is right-handed at and adjacent to the abasic site in the AP/sub F/ 9-mer duplex. Two of the 16 phosphodiester groups exhibit phosphorus resonances outside the normal spectral dispersion indicative of altered torsion angles at two of the phosphate groups in the backbone of the AP/sub F/ 9-mer duplex

Diverging affinity of tospovirus RNA silencing suppressor proteins, NSs, for various RNA duplex molecules

NARCIS (Netherlands)

Schnettler, E.; Hemmes, J.C.; Huisman, R.; Goldbach, R.W.; Prins, M.W.; Kormelink, R.J.M.

2010-01-01

The tospovirus NSs protein was previously shown to suppress the antiviral RNA silencing mechanism in plants. Here the biochemical analysis of NSs proteins from different tospoviruses, using purified NSs or NSs containing cell extracts, is described. The results showed that all tospoviral NSs

MicroRNA mimicry blocks pulmonary fibrosis

Science.gov (United States)

Montgomery, Rusty L; Yu, Guoying; Latimer, Paul A; Stack, Christianna; Robinson, Kathryn; Dalby, Christina M; Kaminski, Naftali; van Rooij, Eva

2014-01-01

Over the last decade, great enthusiasm has evolved for microRNA (miRNA) therapeutics. Part of the excitement stems from the fact that a miRNA often regulates numerous related mRNAs. As such, modulation of a single miRNA allows for parallel regulation of multiple genes involved in a particular disease. While many studies have shown therapeutic efficacy using miRNA inhibitors, efforts to restore or increase the function of a miRNA have been lagging behind. The miR-29 family has gained a lot of attention for its clear function in tissue fibrosis. This fibroblast-enriched miRNA family is downregulated in fibrotic diseases which induces a coordinate increase of many extracellular matrix genes. Here, we show that intravenous injection of synthetic RNA duplexes can increase miR-29 levels in vivo for several days. Moreover, therapeutic delivery of these miR-29 mimics during bleomycin-induced pulmonary fibrosis restores endogenous miR-29 function whereby decreasing collagen expression and blocking and reversing pulmonary fibrosis. Our data support the feasibility of using miRNA mimics to therapeutically increase miRNAs and indicate miR-29 to be a potent therapeutic miRNA for treating pulmonary fibrosis. PMID:25239947

Duplex ultrasound: Indications and findings in a newly created ...

African Journals Online (AJOL)

Duplex ultrasound: Indications and findings in a newly created facility at the University of Calabar Teaching Hospital, Calabar. ... It is recommended that timely referrals be made, and mobile Doppler units be acquired to save more lives and limbs in the developing world. Keywords: Calabar, deep venous thrombosis, duplex ...

An unusual mode of DNA duplex association: Watson-Crick interaction of all-purine deoxyribonucleic acids.

Science.gov (United States)

Battersby, Thomas R; Albalos, Maria; Friesenhahn, Michel J

2007-05-01

Nucleic acid duplexes associating through purine-purine base pairing have been constructed and characterized in a remarkable demonstration of nucleic acids with mixed sequence and a natural backbone in an alternative duplex structure. The antiparallel deoxyribose all-purine duplexes associate specifically through Watson-Crick pairing, violating the nucleobase size-complementarity pairing convention found in Nature. Sequence-specific recognition displayed by these structures makes the duplexes suitable, in principle, for information storage and replication fundamental to molecular evolution in all living organisms. All-purine duplexes can be formed through association of purines found in natural ribonucleosides. Key to the formation of these duplexes is the N(3)-H tautomer of isoguanine, preferred in the duplex, but not in aqueous solution. The duplexes have relevance to evolution of the modern genetic code and can be used for molecular recognition of natural nucleic acids.

Two-dimensional 1H and 31P NMR spectra of a decamer oligodeoxyribonucleotide duplex and a quinoxaline ([MeCys3, MeCys7]TANDEM) drug duplex complex

International Nuclear Information System (INIS)

Powers, R.; Olsen, R.K.; Gorenstein, D.G.

1989-01-01

Assignment of the 1H and 31P NMR spectra of a decamer oligodeoxyribonucleotide duplex, d(CCCGATCGGG), and its quinoxaline ([MeCys3, MeCys7]TANDEM) drug duplex complex has been made by two-dimensional 1H-1H and heteronuclear 31P-1H correlated spectroscopy. The 31P chemical shifts of this 10 base pair oligonucleotide follow the general observation that the more internal the phosphate is located within the oligonucleotide sequence, the more upfield the 31P resonance occurs. While the 31P chemical shifts show sequence-specific variations, they also do not generally follow the Calladine rules previously demonstrated. 31P NMR also provides a convenient monitor of the phosphate ester backbone conformational changes upon binding of the drug to the duplex. Although the quinoxaline drug, [MeCys3, MeCys7]TANDEM, is generally expected to bind to duplex DNA by bis-intercalation, only small 31P chemical shift changes are observed upon binding the drug to duplex d(CCCGATCGGG). Additionally, only small perturbations in the 1H NMR and UV spectra are observed upon binding the drug to the decamer, although association of the drug stabilizes the duplex form relative to the other states. These results are consistent with a non-intercalative mode of association of the drug. Modeling and molecular mechanics energy minimization demonstrate that a novel structure in which the two quinoxaline rings of the drug binds in the minor groove of the duplex is possible

Criteria for the Segmentation of Vowels on Duplex Oscillograms.

Science.gov (United States)

Naeser, Margaret A.

This paper develops criteria for the segmentation of vowels on duplex oscillograms. Previous vowel duration studies have primarily used sound spectrograms. The use of duplex oscillograms, rather than sound spectrograms, permits faster production (real time) at less expense (adding machine paper may be used). The speech signal can be more spread…

Short-hairpin RNA-mediated stable silencing of Grb2 impairs cell growth and DNA synthesis

International Nuclear Information System (INIS)

Di Fulvio, Mauricio; Henkels, Karen M.; Gomez-Cambronero, Julian

2007-01-01

Grb2 is an SH2-SH3 protein adaptor responsible for linking growth factor receptors with intracellular signaling cascades. To study the role of Grb2 in cell growth, we have generated a new COS7 cell line (COS7 shGrb2 ), based on RNAi technology, as null mutations in mammalian Grb2 genes are lethal in early development. This novel cell line continuously expresses a short hairpin RNA that targets endogenous Grb2. Stable COS7 shGrb2 cells had the shGrb2 integrated into the genomic DNA and carried on SiL construct (made refractory to the shRNA-mediated interference), but not with an SH2-deficient mutant (R86K). Thus, a viable knock-down and rescue protocol has demonstrated that Grb2 is crucial for cell proliferation

Duplex-guided percutaneous transluminal angioplasty in iliac arterial occlusive disease.

Science.gov (United States)

Krasznai, A G; Sigterman, T A; Welten, R J; Heijboer, R; Sikkink, C J J M; van de Akker, L H J M; Bouwman, L H

2013-11-01

Chronic renal insufficiency (CRI) is a growing global problem. PTA can be performed without nephrotoxic contrast, utilizing Doppler-ultrasound (Duplex) guidance. Duplex-guided infra-inguinal interventions and access-related interventions have been reported. Duplex-guided iliac interventions have not been performed to any extent because of the anatomic location. In our study we evaluated the safety and efficacy of Duplex-guided percutaneous transluminal angioplasty (DuPTA) in iliac arteries. From June 2012 until February 2013, 31 patients (35 iliac lesions), underwent DuPTA. Indications ranged from Rutherford 3 to 5. Preoperative evaluation included Ankle Brachial Index (ABI), Duplex and MRA. Procedural success was defined as crossing the lesion with a guidewire and dilating or stenting the lesion. Clinical success was defined as 50% reduction in peak systolic velocity (PSV) or clinical improvement. PSV was evaluated after PTA, then at 2 weeks. Clinical results were assessed 2 weeks after the procedure. Procedural success was achieved in 94% of patients (33/35), all of whom also had clinical success. Post-procedural PSV reduction showed an average improvement of 63% (431 cm/s to 153 cm/s). Mean preoperative ABI was 0.72 and improved to 0.88 postoperatively. PTA using Duplex-guidance in significant iliac stenosis is a safe method with major advantages in patients at high risk for developing contrast-induced nephropathy. Copyright © 2013 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Highly Stable Aptamers Selected from a 2′-Fully Modified fGmH RNA Library for Targeting Biomaterials

Science.gov (United States)

Friedman, Adam D.; Kim, Dongwook; Liu, Rihe

2014-01-01

When developed as targeting ligands for the in vivo delivery of biomaterials to biological systems, RNA aptamers immediately face numerous obstacles, in particular nuclease degradation and post-selection 2′ modification. This study aims to develop a novel class of highly stable, 2′-fully modified RNA aptamers that are ideal for the targeted delivery of biomaterials. We demonstrated the facile transcription of a fGmH (2′-F-dG, 2′-OMe-dA/dC/dU) RNA library with unexpected hydrophobicity, the direct selection of aptamers from a fGmH RNA library that bind Staphylococcus aureus Protein A (SpA) as a model target, and the superior nuclease and serum stability of these aptamers compared to 2′-partially modified RNA variants. Characterizations of fGmH RNA aptamers binding to purified SpA and to endogenous SpA present on the surface of S. aureus cells demonstrate fGmH RNA aptamer selectivity and stability. Significantly, fGmH RNA aptamers were able to functionalize, stabilize, and further deliver aggregation-prone silver nanoparticles (AgNPs) to S. aureus with SpA-dependent antimicrobial effects. This study describes a novel aptamer class with considerable potential to improve the in vivo applicability of nucleic acid-based affinity molecules to biomaterials. PMID:25443790

A Full-Duplex MAC Tailored for 5G Wireless Networks

Directory of Open Access Journals (Sweden)

Lucas de Melo Guimarães

2018-01-01

Full Text Available The increasing demands for high-data rate traffic stimulated the development of the fifth-generation (5G mobile networks. The envisioned 5G network is expected to meet its challenge by devising means to further improve spectrum usage. Many alternatives to enhance spectrum usage are being researched, such as massive MIMO, operation in mmWave frequency, cognitive radio, and the employment of full-duplex antennas. Efficient utilization of the potential of any of these technologies faces a set of challenges related to medium access control (MAC schemes. This work focuses on MAC schemes tailored for full-duplex antennas, since they are expected to play a major role in the foreseeable 5G networks. In this context, this paper presents a MAC layer technique to improve total transmission time when full-duplex antennas are employed. Several evaluations in different scenarios are conducted to assess the proposed MAC scheme. Numerical results show that the proposed scheme provides gains up to 156% when compared to a state-of-the-art full-duplex antenna MAC protocol. Compared to traditional half-duplex antenna MAC protocols, the proposed scheme yields gain up to 412%.

Analysing Self Interference Cancellation in Full Duplex Radios

DEFF Research Database (Denmark)

Mahmood, Nurul Huda; Shafique Ansari, Imran; Berardinelli, Gilberto

2016-01-01

Full duplex communication promises a theoretical $100\\%$ throughput gain by doubling the number of simultaneous transmissions. Such compelling gains are conditioned on perfect cancellation of the self interference power resulting from simultaneous transmission and reception. Generally, self...... interference power is modelled as a noise-like constant level interference floor. However, experimental validations have shown that the self interference power is in practice a random variable depending on a number of factors such as the surrounding wireless environment and the degree of interference...... cancellation. In this study, we derive an analytical model for the residual self interference power, and demonstrate various applications of the derived model in analysing the performance of a Full Duplex radio. In general, full duplex communication is found to provide only modest throughput gains over half...

Nanopore Analysis of the 5-Guanidinohydantoin to Iminoallantoin Isomerization in Duplex DNA.

Science.gov (United States)

Zeng, Tao; Fleming, Aaron M; Ding, Yun; Ren, Hang; White, Henry S; Burrows, Cynthia J

2018-04-06

In DNA, guanine oxidation yields diastereomers of 5-guanidinohydantoin (Gh) as one of the major products. In nucleosides and single-stranded DNA, Gh is in a pH-dependent equilibrium with its constitutional isomer iminoallantoin (Ia). Herein, the isomerization reaction between Gh and Ia was monitored in duplex DNA using a protein nanopore by measuring the ionic current when duplex DNA interacts with the pore under an electrophoretic force. Monitoring current levels in this single-molecule method proved to be superior for analysis of population distributions in an equilibrating mixture of four isomers in duplex DNA as a function of pH. The results identified Gh as a major isomer observed when base paired with A, C, or G at pH 6.4-8.4, and Ia was a minor isomer of the reaction mixture that was only observed when the pH was >7.4 in the duplex DNA context. The present results suggest that Gh will be the dominant isomer in duplex DNA under physiological conditions regardless of the base-pairing partner in the duplex.

Development of oxide dispersion strengthened 2205 duplex stainless steel composite

Directory of Open Access Journals (Sweden)

Oladayo OLANIRAN

2015-05-01

Full Text Available Composites of duplex stainless steel were produced by oxide dispersion strengthening with comparatively improved mechanical properties by hot press sintering of partially stabilized Zirconia (PSZ, 3% yttria, mole fraction dispersion in 2205 duplex stainless steels. Ceramic oxide was added as reinforcement, while chromium (Cr and Nickel (Ni were incorporated to maintain the austenitic/ferritic phase balance of the duplex stainless steel. The powders and sintered were characterized in detail using scanning electron microscopy (SEM and X-ray diffraction (XRD. The microstructural evolution and phase formation during oxide dispersion strengthening of duplex stainless steel composites were investigated. The influence of composition variation of the reinforcements on the microstructural and corrosion behaviour in simulated mine water of the composites were investigated. In this manuscript, it was established that composition has great influence on the structure/properties relationship of the composites developed.

Measuring secondary phases in duplex stainless steels

Science.gov (United States)

Calliari, I.; Brunelli, K.; Dabalà, M.; Ramous, E.

2009-01-01

The use of duplex stainless steels is limited by their susceptibility to the formation of dangerous intermetallic phases resulting in detrimental effects on impact toughness and corrosion resistance. This precipitation and the quantitative determinations of the phases have received considerable attention and different precipitation sequences (σ phase, χ phase, and carbides) have been suggested. This study investigates the phase transformation during continuous cooling and isothermal treatments in commercial duplex stainless steel grades and the effects on alloy properties, and compares the most common techniques of analysis.

Structural insights into RISC assembly facilitated by dsRNA-binding domains of human RNA helicase A (DHX9).

Science.gov (United States)

Fu, Qinqin; Yuan, Y Adam

2013-03-01

Intensive research interest has focused on small RNA-processing machinery and the RNA-induced silencing complex (RISC), key cellular machines in RNAi pathways. However, the structural mechanism regarding RISC assembly, the primary step linking small RNA processing and RNA-mediated gene silencing, is largely unknown. Human RNA helicase A (DHX9) was reported to function as an RISC-loading factor, and such function is mediated mainly by its dsRNA-binding domains (dsRBDs). Here, we report the crystal structures of human RNA helicase A (RHA) dsRBD1 and dsRBD2 domains in complex with dsRNAs, respectively. Structural analysis not only reveals higher siRNA duplex-binding affinity displayed by dsRBD1, but also identifies a crystallographic dsRBD1 pair of physiological significance in cooperatively recognizing dsRNAs. Structural observations are further validated by isothermal titration calorimetric (ITC) assay. Moreover, co-immunoprecipitation (co-IP) assay coupled with mutagenesis demonstrated that both dsRBDs are required for RISC association, and such association is mediated by dsRNA. Hence, our structural and functional efforts have revealed a potential working model for siRNA recognition by RHA tandem dsRBDs, and together they provide direct structural insights into RISC assembly facilitated by RHA.

Analysis of Structural Flexibility of Damaged DNA Using Thiol-Tethered Oligonucleotide Duplexes.

Directory of Open Access Journals (Sweden)

Masashi Fujita

Full Text Available Bent structures are formed in DNA by the binding of small molecules or proteins. We developed a chemical method to detect bent DNA structures. Oligonucleotide duplexes in which two mercaptoalkyl groups were attached to the positions facing each other across the major groove were prepared. When the duplex contained the cisplatin adduct, which was proved to induce static helix bending, interstrand disulfide bond formation under an oxygen atmosphere was detected by HPLC analyses, but not in the non-adducted duplex, when the two thiol-tethered nucleosides were separated by six base pairs. When the insert was five and seven base pairs, the disulfide bond was formed and was not formed, respectively, regardless of the cisplatin adduct formation. The same reaction was observed in the duplexes containing an abasic site analog and the (6–4 photoproduct. Compared with the cisplatin case, the disulfide bond formation was slower in these duplexes, but the reaction rate was nearly independent of the linker length. These results indicate that dynamic structural changes of the abasic site- and (6–4 photoproduct-containing duplexes could be detected by our method. It is strongly suggested that the UV-damaged DNA-binding protein, which specifically binds these duplexes and functions at the first step of global-genome nucleotide excision repair, recognizes the easily bendable nature of damaged DNA.

Plant MicroRNA Prediction by Supervised Machine Learning Using C5.0 Decision Trees

Directory of Open Access Journals (Sweden)

Philip H. Williams

2012-01-01

Full Text Available MicroRNAs (miRNAs are nonprotein coding RNAs between 20 and 22 nucleotides long that attenuate protein production. Different types of sequence data are being investigated for novel miRNAs, including genomic and transcriptomic sequences. A variety of machine learning methods have successfully predicted miRNA precursors, mature miRNAs, and other nonprotein coding sequences. MirTools, mirDeep2, and miRanalyzer require “read count” to be included with the input sequences, which restricts their use to deep-sequencing data. Our aim was to train a predictor using a cross-section of different species to accurately predict miRNAs outside the training set. We wanted a system that did not require read-count for prediction and could therefore be applied to short sequences extracted from genomic, EST, or RNA-seq sources. A miRNA-predictive decision-tree model has been developed by supervised machine learning. It only requires that the corresponding genome or transcriptome is available within a sequence window that includes the precursor candidate so that the required sequence features can be collected. Some of the most critical features for training the predictor are the miRNA:miRNA∗ duplex energy and the number of mismatches in the duplex. We present a cross-species plant miRNA predictor with 84.08% sensitivity and 98.53% specificity based on rigorous testing by leave-one-out validation.

Duplex tab exhaust nozzle

Science.gov (United States)

Gutmark, Ephraim Jeff (Inventor); Martens, Steven (nmn) (Inventor)

2012-01-01

An exhaust nozzle includes a conical duct terminating in an annular outlet. A row of vortex generating duplex tabs are mounted in the outlet. The tabs have compound radial and circumferential aft inclination inside the outlet for generating streamwise vortices for attenuating exhaust noise while reducing performance loss.

Function and anatomy of plant siRNA pools derived from hairpin transgenes

Directory of Open Access Journals (Sweden)

Lee Kevin AW

2007-11-01

Full Text Available Abstract Background RNA interference results in specific gene silencing by small-interfering RNAs (siRNAs. Synthetic siRNAs provide a powerful tool for manipulating gene expression but high cost suggests that novel siRNA production methods are desirable. Strong evolutionary conservation of siRNA structure suggested that siRNAs will retain cross-species function and that transgenic plants expressing heterologous siRNAs might serve as useful siRNA bioreactors. Here we report a detailed evaluation of the above proposition and present evidence regarding structural features of siRNAs extracted from plants. Results Testing the gene silencing capacity of plant-derived siRNAs in mammalian cells proved to be very challenging and required partial siRNA purification and design of a highly sensitive assay. Using the above assay we found that plant-derived siRNAs are ineffective for gene silencing in mammalian cells. Plant-derived siRNAs are almost exclusively double-stranded and most likely comprise a mixture of bona fide siRNAs and aberrant partially complementary duplexes. We also provide indirect evidence that plant-derived siRNAs may contain a hitherto undetected physiological modification, distinct from 3' terminal 2-O-methylation. Conclusion siRNAs produced from plant hairpin transgenes and extracted from plants are ineffective for gene silencing in mammalian cells. Thus our findings establish that a previous claim that transgenic plants offer a cost-effective, scalable and sustainable source of siRNAs is unwarranted. Our results also indicate that the presence of aberrant siRNA duplexes and possibly a plant-specific siRNA modification, compromises the gene silencing capacity of plant-derived siRNAs in mammalian cells.

Qualitative comparison of duplex Stirling and absorption refrigerators in domestic applications

Energy Technology Data Exchange (ETDEWEB)

Shao, H. [Global Cooling BV, Zutphen (Netherlands)

2000-07-01

A qualitative comparison has been carried out between the duplex Stirling and the absorption refrigerator for domestic applications. The duplex Stirling has many advantages over the absorption refrigerator on efficiency, modulation, suitability, operating costs, pollution reduction. Based on the state of the art of free-piston gas-bearing and linear-motor Stirling engines and coolers, it appears technically and economically feasible to develop the duplex Stirling to compete with the absorption refrigerator for heat-driven domestic refrigeration. (orig.)

The Mapping of Predicted Triplex DNA:RNA in the Drosophila Genome Reveals a Prominent Location in Development- and Morphogenesis-Related Genes

Directory of Open Access Journals (Sweden)

Claude Pasquier

2017-07-01

Full Text Available Double-stranded DNA is able to form triple-helical structures by accommodating a third nucleotide strand. A nucleic acid triplex occurs according to Hoogsteen rules that predict the stability and affinity of the third strand bound to the Watson–Crick duplex. The “triplex-forming oligonucleotide” (TFO can be a short sequence of RNA that binds to the major groove of the targeted duplex only when this duplex presents a sequence of purine or pyrimidine bases in one of the DNA strands. Many nuclear proteins are known to bind triplex DNA or DNA:RNA, but their biological functions are unexplored. We identified sequences that are capable of engaging as the “triplex-forming oligonucleotide” in both the pre-lncRNA and pre-mRNA collections of Drosophila melanogaster. These motifs were matched against the Drosophila genome in order to identify putative sequences of triplex formation in intergenic regions, promoters, and introns/exons. Most of the identified TFOs appear to be located in the intronic region of the analyzed genes. Computational prediction of the most targeted genes by TFOs originating from pre-lncRNAs and pre-mRNAs revealed that they are restrictively associated with development- and morphogenesis-related gene networks. The refined analysis by Gene Ontology enrichment demonstrates that some individual TFOs present genome-wide scale matches that are located in numerous genes and regulatory sequences. The triplex DNA:RNA computational mapping at the genome-wide scale suggests broad interference in the regulatory process of the gene networks orchestrated by TFO RNAs acting in association simultaneously at multiple sites.

On the Formation and Properties of Interstrand DNA-DNA Cross-links Forged by Reaction of an Abasic Site With the Opposing Guanine Residue of 5′-CAp Sequences in Duplex DNA

Science.gov (United States)

Johnson, Kevin M.; Price, Nathan E.; Wang, Jin; Fekry, Mostafa I.; Dutta, Sanjay; Seiner, Derrick R.; Wang, Yinsheng; Gates, Kent S.

2014-01-01

We recently reported that the aldehyde residue of an abasic (Ap) site in duplex DNA can generate an interstrand cross-link via reaction with a guanine residue on the opposing strand. This finding is intriguing because the highly deleterious nature of interstrand cross-links suggests that even small amounts of Ap-derived cross-links could make a significant contribution to the biological consequences stemming from the generation of Ap sites in cellular DNA. Incubation of 21-bp duplexes containing a central 5′-CAp sequence under conditions of reductive amination (NaCNBH3, pH 5.2) generated much higher yields of cross-linked DNA than reported previously. At pH 7, in the absence of reducing agents, these Ap-containing duplexes also produced cross-linked duplexes that were readily detected on denaturing polyacrylamide gels. Cross-link formation was not highly sensitive to reaction conditions and, once formed, the cross-link was stable to a variety of work-up conditions. Results of multiple experiments including MALDI-TOF mass spectrometry, gel mobility, methoxyamine capping of the Ap aldehyde, inosine-for-guanine replacement, hydroxyl radical footprinting, and LCMS/MS were consistent with a cross-linking mechanism involving reversible reaction of the Ap aldehyde residue with the N2-amino group of the opposing guanine residue in 5′-CAp sequences to generate hemiaminal, imine, or cyclic hemiaminal cross-links (7-10) that were irreversibly converted under conditions of reductive amination (NaCNBH3/pH 5.2) to a stable amine linkage. Further support for the importance of the exocyclic N2-amino group in this reaction was provided by an experiment showing that installation of a 2-aminopurine-thymine base pair at the cross-linking site produced high yields (15-30%) of a cross-linked duplex at neutral pH, in the absence of NaCNBH3. PMID:23215239

The hepatitis C virus Core protein is a potent nucleic acid chaperone that directs dimerization of the viral (+) strand RNA in vitro.

Science.gov (United States)

Cristofari, Gaël; Ivanyi-Nagy, Roland; Gabus, Caroline; Boulant, Steeve; Lavergne, Jean-Pierre; Penin, François; Darlix, Jean-Luc

2004-01-01

The hepatitis C virus (HCV) is an important human pathogen causing chronic hepatitis, liver cirrhosis and hepatocellular carcinoma. HCV is an enveloped virus with a positive-sense, single-stranded RNA genome encoding a single polyprotein that is processed to generate viral proteins. Several hundred molecules of the structural Core protein are thought to coat the genome in the viral particle, as do nucleocapsid (NC) protein molecules in Retroviruses, another class of enveloped viruses containing a positive-sense RNA genome. Retroviral NC proteins also possess nucleic acid chaperone properties that play critical roles in the structural remodelling of the genome during retrovirus replication. This analogy between HCV Core and retroviral NC proteins prompted us to investigate the putative nucleic acid chaperoning properties of the HCV Core protein. Here we report that Core protein chaperones the annealing of complementary DNA and RNA sequences and the formation of the most stable duplex by strand exchange. These results show that the HCV Core is a nucleic acid chaperone similar to retroviral NC proteins. We also find that the Core protein directs dimerization of HCV (+) RNA 3' untranslated region which is promoted by a conserved palindromic sequence possibly involved at several stages of virus replication.

RNA-binding properties and RNA chaperone activity of human peroxiredoxin 1

International Nuclear Information System (INIS)

Kim, Ji-Hee; Lee, Jeong-Mi; Lee, Hae Na; Kim, Eun-Kyung; Ha, Bin; Ahn, Sung-Min; Jang, Ho Hee; Lee, Sang Yeol

2012-01-01

Highlights: ► hPrx1 has RNA-binding properties. ► hPrx1 exhibits helix-destabilizing activity. ► Cold stress increases hPrx1 level in the nuclear fraction. ► hPrx1 enhances the viability of cells exposed to cold stress. -- Abstract: Human peroxiredoxin 1 (hPrx1), a member of the peroxiredoxin family, detoxifies peroxide substrates and has been implicated in numerous biological processes, including cell growth, proliferation, differentiation, apoptosis, and redox signaling. To date, Prx1 has not been implicated in RNA metabolism. Here, we investigated the ability of hPrx1 to bind RNA and act as an RNA chaperone. In vitro, hPrx1 bound to RNA and DNA, and unwound nucleic acid duplexes. hPrx1 also acted as a transcription anti-terminator in an assay using an Escherichia coli strain containing a stem–loop structure upstream of the chloramphenicol resistance gene. The overall cellular level of hPrx1 expression was not increased at low temperatures, but the nuclear level of hPrx1 was increased. In addition, hPrx1 overexpression enhanced the survival of cells exposed to cold stress, whereas hPrx1 knockdown significantly reduced cell survival under the same conditions. These findings suggest that hPrx1 may perform biological functions as a RNA-binding protein, which are distinctive from known functions of hPrx1 as a reactive oxygen species scavenger.

The VP3 factor from viruses of Birnaviridae family suppresses RNA silencing by binding both long and small RNA duplexes.

Science.gov (United States)

Valli, Adrian; Busnadiego, Idoia; Maliogka, Varvara; Ferrero, Diego; Castón, José R; Rodríguez, José Francisco; García, Juan Antonio

2012-01-01

RNA silencing is directly involved in antiviral defense in a wide variety of eukaryotic organisms, including plants, fungi, invertebrates, and presumably vertebrate animals. The study of RNA silencing-mediated antiviral defences in vertebrates is hampered by the overlap with other antiviral mechanisms; thus, heterologous systems are often used to study the interplay between RNA silencing and vertebrate-infecting viruses. In this report we show that the VP3 protein of the avian birnavirus Infectious bursal disease virus (IBDV) displays, in addition to its capacity to bind long double-stranded RNA, the ability to interact with double-stranded small RNA molecules. We also demonstrate that IBDV VP3 prevents the silencing mediated degradation of a reporter mRNA, and that this silencing suppression activity depends on its RNA binding ability. Furthermore, we find that the anti-silencing activity of IBDV VP3 is shared with the homologous proteins expressed by both insect- and fish-infecting birnaviruses. Finally, we show that IBDV VP3 can functionally replace the well-characterized HCPro silencing suppressor of Plum pox virus, a potyvirus that is unable to infect plants in the absence of an active silencing suppressor. Altogether, our results support the idea that VP3 protects the viral genome from host sentinels, including those of the RNA silencing machinery.

A Dual-Specific Targeting Approach Based on the Simultaneous Recognition of Duplex and Quadruplex Motifs.

Science.gov (United States)

Nguyen, Thi Quynh Ngoc; Lim, Kah Wai; Phan, Anh Tuân

2017-09-20

Small-molecule ligands targeting nucleic acids have been explored as potential therapeutic agents. Duplex groove-binding ligands have been shown to recognize DNA in a sequence-specific manner. On the other hand, quadruplex-binding ligands exhibit high selectivity between quadruplex and duplex, but show limited discrimination between different quadruplex structures. Here we propose a dual-specific approach through the simultaneous application of duplex- and quadruplex-binders. We demonstrated that a quadruplex-specific ligand and a duplex-specific ligand can simultaneously interact at two separate binding sites of a quadruplex-duplex hybrid harbouring both quadruplex and duplex structural elements. Such a dual-specific targeting strategy would combine the sequence specificity of duplex-binders and the strong binding affinity of quadruplex-binders, potentially allowing the specific targeting of unique quadruplex structures. Future research can be directed towards the development of conjugated compounds targeting specific genomic quadruplex-duplex sites, for which the linker would be highly context-dependent in terms of length and flexibility, as well as the attachment points onto both ligands.

Full-Duplex opportunistic relay selection in future spectrum-sharing networks

KAUST Repository

Khafagy, Mohammad Galal; Alouini, Mohamed-Slim; Aï ssa, Sonia

2015-01-01

We propose and analyze the performance of full-duplex relay selection in primary/secondary spectrum-sharing networks. Contrary to half-duplex relaying, full-duplex relaying (FDR) enables simultaneous listening/forwarding at the secondary relay, thereby allowing for a higher spectral efficiency. However, since the source and relay simultaneously transmit in FDR, their superimposed signal at the primary receiver should now satisfy the existing interference constraint which can considerably limit the secondary network throughput. In this regard, relay selection can offer an adequate solution to boost the secondary throughput while satisfying the imposed interference limit. We first analyze the performance of opportunistic relay selection among a cluster of full-duplex decode-and-forward relays with self-interference by deriving the exact cumulative distribution function of its end-to-end signal-to-noise ratio. Second, we evaluate the end-to-end performance of relay selection with interference constraints due to the presence of a primary receiver. Finally, the presented exact theoretical findings are verified by numerical simulations.

Full-Duplex opportunistic relay selection in future spectrum-sharing networks

KAUST Repository

Khafagy, Mohammad Galal

2015-06-01

We propose and analyze the performance of full-duplex relay selection in primary/secondary spectrum-sharing networks. Contrary to half-duplex relaying, full-duplex relaying (FDR) enables simultaneous listening/forwarding at the secondary relay, thereby allowing for a higher spectral efficiency. However, since the source and relay simultaneously transmit in FDR, their superimposed signal at the primary receiver should now satisfy the existing interference constraint which can considerably limit the secondary network throughput. In this regard, relay selection can offer an adequate solution to boost the secondary throughput while satisfying the imposed interference limit. We first analyze the performance of opportunistic relay selection among a cluster of full-duplex decode-and-forward relays with self-interference by deriving the exact cumulative distribution function of its end-to-end signal-to-noise ratio. Second, we evaluate the end-to-end performance of relay selection with interference constraints due to the presence of a primary receiver. Finally, the presented exact theoretical findings are verified by numerical simulations.

Duplex Ultrasonography Has Limited Utility in Detection of Postoperative DVT After Primary Total Joint Arthroplasty.

Science.gov (United States)

Vira, Shaleen; Ramme, Austin J; Alaia, Michael J; Steiger, David; Vigdorchik, Jonathan M; Jaffe, Frederick

2016-07-01

Duplex ultrasound is routinely used to evaluate suspected deep venous thrombosis after total joint arthroplasty. When there is a clinical suspicion for a pulmonary embolism, a chest angiogram (chest CTA) is concomitantly obtained. Two questions were addressed: First, for the population of patients who receive duplex ultrasound after total joint arthroplasty, what is the rate of positive results? Second, for these patients, how many of these also undergo chest CTA for clinical suspicion of pulmonary embolus and how many of these tests are positive? Furthermore, what is the correlation between duplex ultrasound results and chest CTA results? A retrospective chart review was conducted of total joint replacement patients in 2011 at a single institution. Inclusion criteria were adult patients who underwent a postoperative duplex ultrasonography for clinical suspicion of deep venous thrombosis (DVT). Demographic data, result of duplex scan, clinical indications for obtaining the duplex scan, and DVT prophylaxis used were recorded. Additionally, if a chest CTA was obtained for clinical suspicion for pulmonary embolus, results and clinical indication for obtaining the test were recorded. The rate of positive results for duplex ultrasonography and chest CTA was computed and correlated based on clinical indications. Two hundred ninety-five patients underwent duplex ultrasonography of which only 0.7% were positive for a DVT. One hundred three patients underwent a chest CTA for clinical suspicion of a pulmonary embolism (PE) of which 26 revealed a pulmonary embolus, none of which had a positive duplex ultrasound. Postoperative duplex scans have a low rate of positive results. A substantial number of patients with negative duplex results subsequently underwent chest CTA for clinical suspicion for which a pulmonary embolus was found, presumably resulting from a DVT despite negative duplex ultrasound result. A negative duplex ultrasonography should not rule out the presence of a

Full-Duplex Communications in Large-Scale Cellular Networks

KAUST Repository

AlAmmouri, Ahmad

2016-04-01

In-band full-duplex (FD) communications have been optimistically promoted to improve the spectrum utilization and efficiency. However, the penetration of FD communications to the cellular networks domain is challenging due to the imposed uplink/downlink interference. This thesis presents a tractable framework, based on stochastic geometry, to study FD communications in multi-tier cellular networks. Particularly, we assess the FD communications effect on the network performance and quantify the associated gains. The study proves the vulnerability of the uplink to the downlink interference and shows that the improved FD rate gains harvested in the downlink (up to 97%) comes at the expense of a significant degradation in the uplink rate (up to 94%). Therefore, we propose a novel fine-grained duplexing scheme, denoted as α-duplex scheme, which allows a partial overlap between the uplink and the downlink frequency bands. We derive the required conditions to harvest rate gains from the α-duplex scheme and show its superiority to both the FD and half-duplex (HD) schemes. In particular, we show that the α-duplex scheme provides a simultaneous improvement of 28% for the downlink rate and 56% for the uplink rate. We also show that the amount of the overlap can be optimized based on the network design objective. Moreover, backward compatibility is an essential ingredient for the success of new technologies. In the context of in-band FD communication, FD base stations (BSs) should support HD users\\' equipment (UEs) without sacrificing the foreseen FD gains. The results show that FD-UEs are not necessarily required to harvest rate gains from FD-BSs. In particular, the results show that adding FD-UEs to FD-BSs offers a maximum of 5% rate gain over FD-BSs and HD-UEs case, which is a marginal gain compared to the burden required to implement FD transceivers at the UEs\\' side. To this end, we shed light on practical scenarios where HD-UEs operation with FD-BSs outperforms the

Insight into a conformation of the PNA-PNA duplex with (2‧R,4‧R)- and (2‧R,4‧S)-prolyl-(1S,2S)-2-aminocyclopentanecarboxylic acid backbones

Science.gov (United States)

Maitarad, Amphawan; Poomsuk, Nattawee; Vilaivan, Chotima; Vilaivan, Tirayut; Siriwong, Khatcharin

2018-04-01

Suitable conformations for peptide nucleic acid (PNA) self-hybrids with (2‧R,4‧R)- and (2‧R,4‧S)-prolyl-(1S,2S)-2-aminocyclopentanecarboxylic acid backbones (namely, acpcPNA and epi-acpcPNA, respectively) were investigated based on molecular dynamics simulations. The results revealed that hybridization of the acpcPNA was observed only in the parallel direction, with a conformation close to the P-type structure. In contrast, self-hybrids of the epi-acpcPNA were formed in the antiparallel and parallel directions; the antiparallel duplex adopted the B-form conformation, and the parallel duplex was between B- and P-forms. The calculated binding energies and the experimental data indicate that the antiparallel epi-acpcPNA self-hybrid was more stable than the parallel duplex.

Small RNA sequence analysis of adenovirus VA RNA-derived miRNAs reveals an unexpected serotype-specific difference in structure and abundance.

Directory of Open Access Journals (Sweden)

Wael Kamel

Full Text Available Human adenoviruses (HAds encode for one or two highly abundant virus-associated RNAs, designated VA RNAI and VA RNAII, which fold into stable hairpin structures resembling miRNA precursors. Here we show that the terminal stem of the VA RNAs originating from Ad4, Ad5, Ad11 and Ad37, all undergo Dicer dependent processing into virus-specific miRNAs (so-called mivaRNAs. We further show that the mivaRNA duplex is subjected to a highly asymmetric RISC loading with the 3'-strand from all VA RNAs being the favored strand, except for the Ad37 VA RNAII, where the 5'-mivaRNAII strand was preferentially assembled into RISC. Although the mivaRNA seed sequences are not fully conserved between the HAds a bioinformatics prediction approach suggests that a large fraction of the VA RNAII-, but not the VA RNAI-derived mivaRNAs still are able to target the same cellular genes. Using small RNA deep sequencing we demonstrate that the Dicer processing event in the terminal stem of the VA RNAs is not unique and generates 3'-mivaRNAs with a slight variation of the position of the 5' terminal nucleotide in the RISC loaded guide strand. Also, we show that all analyzed VA RNAs, except Ad37 VA RNAI and Ad5 VA RNAII, utilize an alternative upstream A start site in addition to the classical +1 G start site. Further, the 5'-mivaRNAs with an A start appears to be preferentially incorporated into RISC. Although the majority of mivaRNA research has been done using Ad5 as the model system our analysis demonstrates that the mivaRNAs expressed in Ad11- and Ad37-infected cells are the most abundant mivaRNAs associated with Ago2-containing RISC. Collectively, our results show an unexpected variability in Dicer processing of the VA RNAs and a serotype-specific loading of mivaRNAs into Ago2-based RISC.

Considerations in Duplex Investment.

Science.gov (United States)

Wright, Arthur; Goen, Tom

Problems of duplex investment are noted in the introduction to this booklet designed to provide a technique by which the investment decision can be approached, develop estimates of typical costs and returns under differing conditions, and encourage investors to analyze objectives and conditions before the decision to buy or build is made. A…

Effect of Cavity Size of Mesoporous Silica on Short DNA Duplex Stability.

Science.gov (United States)

Masuda, Tsubasa; Shibuya, Yuuta; Arai, Shota; Kobayashi, Sayaka; Suzuki, Sotaro; Kijima, Jun; Itoh, Tetsuji; Sato, Yusuke; Nishizawa, Seiichi; Yamaguchi, Akira

2018-05-15

We studied the stabilities of short (4- and 3-bp) DNA duplexes within silica mesopores modified with a positively charged trimethyl aminopropyl (TMAP) monolayer (BJH pore diameter 1.6-7.4 nm). The DNA fragments with fluorescent dye were introduced into the pores, and their fluorescence resonance energy transfer (FRET) response was measured to estimate the structuring energies of the short DNA duplexes under cryogenic conditions (temperature 233-323 K). The results confirmed the enthalpic stability gain of the duplex within size-matched pores (1.6 and 2.3 nm). The hybridization equilibrium constants found for the size-matched pores were 2 orders of magnitude larger than those for large pores (≥3.5 nm), and this size-matching effect for the enhanced duplex stability was explained by a tight electrostatic interaction between the duplex and the surface TMAP groups. These results indicate the requirement of the precise regulation of mesopore size to ensure the stabilization of hydrogen-bonded supramolecular assemblies.

Renal pelvis urothelial carcinoma of the upper moiety in complete right renal duplex: a case report.

Science.gov (United States)

Zhang, Yiran; Yu, Quanfeng; Zhang, Zhihong; Liu, Ranlu; Xu, Yong

2015-01-01

Urothelial carcinoma (UC) originated from renal pelvis is the common tumor of the urinary system, however, neoplasia of the renal pelvis in duplex kidneys is extremely rare, especially in the complete renal and ureteral duplex cases. We present the first case of renal pelvis UC of the upper moiety in a complete right renal duplex. This male patient has bilateral complete renal and ureteral duplex. To the best of our knowledge, this is the first reported case of renal pelvis UC in a complete renal duplex system. After this experience we feel that the diagnosis of renal pelvis UC in duplex kidneys is not so easy, and once the diagnosis is determined, the whole renal duplex units and bladder cuff or ectopic orifice should be excised radically.

The VP3 factor from viruses of Birnaviridae family suppresses RNA silencing by binding both long and small RNA duplexes.

Directory of Open Access Journals (Sweden)

Adrian Valli

Full Text Available RNA silencing is directly involved in antiviral defense in a wide variety of eukaryotic organisms, including plants, fungi, invertebrates, and presumably vertebrate animals. The study of RNA silencing-mediated antiviral defences in vertebrates is hampered by the overlap with other antiviral mechanisms; thus, heterologous systems are often used to study the interplay between RNA silencing and vertebrate-infecting viruses. In this report we show that the VP3 protein of the avian birnavirus Infectious bursal disease virus (IBDV displays, in addition to its capacity to bind long double-stranded RNA, the ability to interact with double-stranded small RNA molecules. We also demonstrate that IBDV VP3 prevents the silencing mediated degradation of a reporter mRNA, and that this silencing suppression activity depends on its RNA binding ability. Furthermore, we find that the anti-silencing activity of IBDV VP3 is shared with the homologous proteins expressed by both insect- and fish-infecting birnaviruses. Finally, we show that IBDV VP3 can functionally replace the well-characterized HCPro silencing suppressor of Plum pox virus, a potyvirus that is unable to infect plants in the absence of an active silencing suppressor. Altogether, our results support the idea that VP3 protects the viral genome from host sentinels, including those of the RNA silencing machinery.

Expression of a natural antisense transcript of Cg-Foxl2 during the gonadic differentiation of the oyster Crassostrea gigas: first demonstration in the gonads of a lophotrochozoa species.

Science.gov (United States)

Santerre, C; Sourdaine, P; Martinez, A-S

2012-01-01

In the oyster Crassostrea gigas, a successive hermaphrodite, Cg-Foxl2, an ortholog of Foxl2, is suspected to be involved in vitellogenesis or female sex determination. The existence of a natural antisense transcript (NAT) of this factor has been suspected in gonads but needs to be confirmed to better understand the early events of the gonadic differentiation. The occurrence of this NAT was studied by orientation-specific RT-PCR. The NAT and its mRNA expressions were investigated during the development and in adults by real-time PCR and in situ hybridization. The presence of stable in vivo RNA-RNA duplexes was also explored by RNase protection-based approach. This work is the first evidence of characterization of a NAT in the gonads of mollusks and Lophotrochozoa. This NAT named Cg-Foxl2os is supposed to be polyadenylated and forms RNA-RNA duplexes with its mRNA. Cg-Foxl2os is significantly more expressed than Cg-Foxl2 in 2-month-old spats and in mature males. It is co-localized with the mRNA in the cytoplasm of spermatogonia and spermatocytes. The results of this study demonstrate the existence of a NAT of Cg-Foxl2 in the gonads of C. gigas. It may regulate its mRNA expression through formation of cytoplasmic RNA-RNA duplexes during the oyster gonadic differentiation. Copyright © 2012 S. Karger AG, Basel.

Retinitis Pigmentosa Mutations in Bad Response to Refrigeration 2 (Brr2) Impair ATPase and Helicase Activity.

Science.gov (United States)

Ledoux, Sarah; Guthrie, Christine

2016-06-03

Brr2 is an RNA-dependent ATPase required to unwind the U4/U6 snRNA duplex during spliceosome assembly. Mutations within the ratchet helix of the Brr2 RNA binding channel result in a form of degenerative human blindness known as retinitis pigmentosa (RP). The biochemical consequences of these mutations on Brr2's RNA binding, helicase, and ATPase activity have not yet been characterized. Therefore, we identified the largest construct of Brr2 that is soluble in vitro, which truncates the first 247 amino acids of the N terminus (Δ247-Brr2), to characterize the effects of the RP mutations on Brr2 activity. The Δ247-Brr2 RP mutants exhibit a gradient of severity of weakened RNA binding, reduced helicase activity, and reduced ATPase activity compared with wild type Δ247-Brr2. The globular C-terminal Jab1/Mpn1-like domain of Prp8 increases the ability of Δ247-Brr2 to bind the U4/U6 snRNA duplex at high pH and increases Δ247-Brr2's RNA-dependent ATPase activity and the extent of RNA unwinding. However, this domain of Prp8 does not differentially affect the Δ247-Brr2 RP mutants compared with the wild type Δ247-Brr2. When stimulated by Prp8, wild type Δ247-Brr2 is able to unwind long stable duplexes in vitro, and even the RP mutants capable of binding RNA with tight affinity are incapable of fully unwinding short duplex RNAs. Our data suggest that the RP mutations within the ratchet helix impair Brr2 translocation through RNA helices. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Full-Duplex Relay Selection in Cognitive Underlay Networks

KAUST Repository

Khafagy, Mohammad Galal

2017-09-30

In this work, we analyze the performance of full-duplex relay selection (FDRS) in spectrum-sharing networks. Contrary to half-duplex relaying, full-duplex relaying (FDR) enables simultaneous listening/forwarding at the secondary relay(s), thereby allowing for a higher spectral efficiency. However, since the source and relay simultaneously transmit in FDR, their superimposed signal at the primary receiver should now satisfy the existing interference constraint, which can considerably limit the secondary network throughput. In this regard, relay selection can offer an adequate solution to boost the secondary throughput while satisfying the imposed interference limit. We first analyze the performance of opportunistic FDRS with residual self-interference (RSI) by deriving the exact cumulative distribution function of its end-to-end signal-to-interference-plus-noise ratio under Nakagami-m fading. We also evaluate the offered diversity gain of relay selection for different full-duplex cooperation schemes in the presence/absence of a direct source-destination link. When the adopted RSI link gain model is sublinear in the relay power, which agrees with recent research findings, we show that remarkable diversity gain can be recovered even in the presence of an interfering direct link. Second, we evaluate the end-to-end performance of FDRS with interference constraints due to the presence of a primary receiver. Finally, the presented exact theoretical findings are verified by numerical simulations.

THE INFLUENCE OF POSTHEAT TREATMENT ON FERRITE REDISTRIBUTION IN DUPLEX STEELS ELECTRON BEAM WELDS

OpenAIRE

Zita Iždinská; František Kolenič

2009-01-01

The duplex stainless steel is two-phase steel with the structure composed of austenite and ferrite with optimum austenite/ferrite proportion 50%. At present, classical arc processes for welding duplex steels are generally regarded as acceptable. On the other hand electron and laser beam welding is up to now considered less suitable for welding duplex steels. The submitted work presents the results of testing various thermal conditions at welding duplex stainless steel with electron beam. It w...

Sensitivity of hydrogen bonds of DNA and RNA to hydration, as gauged by 1JNH measurements in ethanol-water mixtures

International Nuclear Information System (INIS)

Manalo, Marlon N.; Kong Xiangming; LiWang, Andy

2007-01-01

Hydrogen-bond lengths of nucleic acids are (1) longer in DNA than in RNA, and (2) sequence dependent. The physicochemical basis for these variations in hydrogen-bond lengths is unknown, however. Here, the notion that hydration plays a significant role in nucleic acid hydrogen-bond lengths is tested. Watson-Crick N1...N3 hydrogen-bond lengths of several DNA and RNA duplexes are gauged using imino 1 J NH measurements, and ethanol is used as a cosolvent to lower water activity. We find that 1 J NH values of DNA and RNA become less negative with added ethanol, which suggests that mild dehydration reduces hydrogen-bond lengths even as the overall thermal stabilities of these duplexes decrease. The 1 J NH of DNA are increased in 8 mol% ethanol to those of RNA in water, which suggests that the greater hydration of DNA plays a significant role in its longer hydrogen bonds. The data also suggest that ethanol-induced dehydration is greater for the more hydrated G:C base pairs and thereby results in greater hydrogen-bond shortening than for the less hydrated A:T/U base pairs of DNA and RNA

In-Band α-Duplex Scheme for Cellular Networks: A Stochastic Geometry Approach

KAUST Repository

Alammouri, Ahmad

2016-07-13

In-band full-duplex (FD) communications have been optimistically promoted to improve the spectrum utilization and efficiency. However, the penetration of FD communications to the cellular networks domain is challenging due to the imposed uplink/downlink interference. This paper presents a tractable framework, based on stochastic geometry, to study FD communications in cellular networks. Particularly, we assess the FD communications effect on the network performance and quantify the associated gains. The study proves the vulnerability of the uplink to the downlink interference and shows that FD rate gains harvested in the downlink (up to 97%) come at the expense of a significant degradation in the uplink rate (up to 94%). Therefore, we propose a novel fine-grained duplexing scheme, denoted as -duplex scheme, which allows a partial overlap between the uplink and the downlink frequency bands. We derive the required conditions to harvest rate gains from the -duplex scheme and show its superiority to both the FD and half-duplex (HD) schemes. In particular, we show that the -duplex scheme provides a simultaneous improvement of 28% for the downlink rate and 56% for the uplink rate. Finally, we show that the amount of the overlap can be optimized based on the network design objective.

Identification of glucose-fermenting bacteria present in an in-vitro model of the human inetstine by RNA-stable isotope probing

NARCIS (Netherlands)

Egert, M.G.G.; Graaf, de A.A.; Maathuis, A.; Waard, de P.; Plugge, C.M.; Smidt, H.; Deutz, N.E.P.; Dijkema, C.; Vos, de W.M.; Venema, K.

2007-01-01

16S rRNA-based stable isotope probing (SIP) and nuclear magnetic resonance (NMR) spectroscopy-based metabolic profiling were used to identify bacteria fermenting glucose under conditions simulating the human intestine. The TIM-2 in vitro model of the human intestine was inoculated with a GI tract

Identification of glucose-fermenting bacteria present in an in vitro model of the human intestine by RNA-stable isotope probing

NARCIS (Netherlands)

Egert, M.; Graaf, A.A. de; Maathuis, A.; Waard, P. de; Plugge, C.M.; Smidt, H.; Deutz, N.E.P.; Dijkema, C.; Vos, W.M. de; Venema, K.

2007-01-01

16S rRNA-based stable isotope probing (SIP) and nuclear magnetic resonance (NMR) spectroscopy-based metabolic profiling were used to identify bacteria fermenting glucose under conditions simulating the human intestine. The TIM-2 in vitro model of the human intestine was inoculated with a GI tract

An evaluation of nuclear design characteristics of duplex burnable poison rods for extended cycle core

International Nuclear Information System (INIS)

Lee, D. J.; Kim, M. H.; Song, K. W.

2003-01-01

Nuclear design characteristics of duplex burnable poison rod were evaluated for three integral type burnable absorbers; Gadolinia, Erbia and IFBA. Inter-comparison was done for both 12 and 24 month cycle for Korean Standard Nuclear Plant. Fuel assemblies with duplex BP was designed to the equivalent assembly with 8 and 16 gadolinia BP 2 . Duplex BP is composed of inner region of natural U-Gd 2 O 3 , and outer shell of, UO 2 -Er2O 3 . In order to evaluate the duplex BP, assemblies with erbia and IFBA were compared with alternative options. A sensitivity studies were performed to the size of region, compositions and location of duplex BPs. It was shown that duplex BP gave favorable k-infinite curve to burnup, but IFBA provided the least residual reactivity penalty as EOC. Erbia was good for more negative MTCs. IFBA and erbia had better neutronic performance than gadolinia od duplex BP in the aspect of pin power peaking

CMOS serial link for fully duplexed data communication

Science.gov (United States)

Lee, Kyeongho; Kim, Sungjoon; Ahn, Gijung; Jeong, Deog-Kyoon

1995-04-01

This paper describes a CMOS serial link allowing fully duplexed 500 Mbaud serial data communication. The CMOS serial link is a robust and low-cost solution to high data rate requirements. A central charge pump PLL for generating multiphase clocks for oversampling is shared by several serial link channels. Fully duplexed serial data communication is realized in the bidirectional bridge by separating incoming data from the mixed signal on the cable end. The digital PLL accomplishes process-independent data recovery by using a low-ratio oversampling, a majority voting, and a parallel data recovery scheme. Mostly, digital approach could extend its bandwidth further with scaled CMOS technology. A single channel serial link and a charge pump PLL are integrated in a test chip using 1.2 micron CMOS process technology. The test chip confirms upto 500 Mbaud unidirectional mode operation and 320 Mbaud fully duplexed mode operation with pseudo random data patterns.

Optimisation of welding procedures for duplex and superduplex stainless steels

International Nuclear Information System (INIS)

Westin, Elin M.

2014-01-01

Austenitic stainless steels are increasingly being replaced by duplex grades that can offer similar corrosion resistance with far higher strength. This increased strength makes it possible to reduce material consumption whilst also decreasing transport and construction costs. Although established welding methods used for austenitic steels can be used for duplex steels, modification of the procedures can lead to improved results. This paper reviews the welding of duplex stainless steel and examines precautions that may be required. The advantages and disadvantages of different welding methods are highlighted and some high productivity solutions are presented. The application of a more efficient process with a high deposition rate (e.g. flux- cored arc welding) can decrease labour costs. Further close control of heat input and interpass temperature can result in more favourable microstructures and final properties. Although welding adversely affects the corrosion resistance of austenitic and duplex stainless steels, particularly the pitting resistance, relative to the parent material, this problem can be minimised by proper backing gas protection and subsequent pickling.

Features of residual stresses in duplex stainless steel butt welds

Science.gov (United States)

Um, Tae-Hwan; Lee, Chin-Hyung; Chang, Kyong-Ho; Nguyen Van Do, Vuong

2018-04-01

Duplex stainless steel finds increasing use as an alternative to austenitic stainless steel, particularly where chloride or sulphide stress corrosion cracking is of primary concern, due to the excellent combination of strength and corrosion resistance. During welding, duplex stainless steel does not create the same magnitude or distribution of weld-induced residual stresses as those in welded austenitic stainless steel due to the different physical and mechanical properties between them. In this work, an experimental study on the residual stresses in butt-welded duplex stainless steel is performed utilizing the layering technique to investigate the characteristics of residual stresses in the weldment. Three-dimensional thermos-mechanical-metallurgical finite element analysis is also performed to confirm the residual stress measurements.

Platinum Interference with siRNA Non-seed Regions Fine-Tunes Silencing Capacity

DEFF Research Database (Denmark)

Hedman, Hanna K; Kirpekar, Finn; Elmroth, Sofi K C

2011-01-01

expression, and the other one focused on the function of endogenous miRNAs. In both cases, the active molecule consists of a ∼20-nucleotide-long RNA duplex. In the siRNA case, improved systemic stability is of central interest for its further development toward clinical applications. With respect to mi......RNA processing and function, understanding its influence on mRNA targeting and the silencing ability of individual miRNAs, e.g., under pathological conditions, remains a scientific challenge. In the present study, a model system is presented where the influence of the two clinically used anticancer drugs......, cisplatin and oxaliplatin, on siRNA's silencing capacity has been evaluated. More specifically, siRNAs targeting the 3' UTR region of Wnt-5a mRNA (NM_003352) were constructed, and the biologically active antisense RNA strand was pre-platinated. Platinum adducts were detected and characterized...

Micromechanics of base pair unzipping in the DNA duplex

International Nuclear Information System (INIS)

Volkov, Sergey N; Paramonova, Ekaterina V; Yakubovich, Alexander V; Solov’yov, Andrey V

2012-01-01

All-atom molecular dynamics (MD) simulations of DNA duplex unzipping in a water environment were performed. The investigated DNA double helix consists of a Drew-Dickerson dodecamer sequence and a hairpin (AAG) attached to the end of the double-helix chain. The considered system is used to examine the process of DNA strand separation under the action of an external force. This process occurs in vivo and now is being intensively investigated in experiments with single molecules. The DNA dodecamer duplex is consequently unzipped pair by pair by means of the steered MD. The unzipping trajectories turn out to be similar for the duplex parts with G⋅C content and rather distinct for the parts with A⋅T content. It is shown that during the unzipping each pair experiences two types of motion: relatively quick rotation together with all the duplex and slower motion in the frame of the unzipping fork. In the course of opening, the complementary pair passes through several distinct states: (i) the closed state in the double helix, (ii) the metastable preopened state in the unzipping fork and (iii) the unbound state. The performed simulations show that water molecules participate in the stabilization of the metastable states of the preopened base pairs in the DNA unzipping fork. (paper)

Diagnostic Potential of Plasmatic MicroRNA Signatures in Stable and Unstable Angina

Science.gov (United States)

D'Alessandra, Yuri; Carena, Maria Cristina; Spazzafumo, Liana; Martinelli, Federico; Bassetti, Beatrice; Devanna, Paolo; Rubino, Mara; Marenzi, Giancarlo; Colombo, Gualtiero I.; Achilli, Felice; Maggiolini, Stefano; Capogrossi, Maurizio C.; Pompilio, Giulio

2013-01-01

Purpose We examined circulating miRNA expression profiles in plasma of patients with coronary artery disease (CAD) vs. matched controls, with the aim of identifying novel discriminating biomarkers of Stable (SA) and Unstable (UA) angina. Methods An exploratory analysis of plasmatic expression profile of 367 miRNAs was conducted in a group of SA and UA patients and control donors, using TaqMan microRNA Arrays. Screening confirmation and expression analysis were performed by qRT-PCR: all miRNAs found dysregulated were examined in the plasma of troponin-negative UA (n=19) and SA (n=34) patients and control subjects (n=20), matched for sex, age, and cardiovascular risk factors. In addition, the expression of 14 known CAD-associated miRNAs was also investigated. Results Out of 178 miRNAs consistently detected in plasma samples, 3 showed positive modulation by CAD when compared to controls: miR-337-5p, miR-433, and miR-485-3p. Further, miR-1, -122, -126, -133a, -133b, and miR-199a were positively modulated in both UA and SA patients, while miR-337-5p and miR-145 showed a positive modulation only in SA or UA patients, respectively. ROC curve analyses showed a good diagnostic potential (AUC ≥ 0.85) for miR-1, -126, and -483-5p in SA and for miR-1, -126, and -133a in UA patients vs. controls, respectively. No discriminating AUC values were observed comparing SA vs. UA patients. Hierarchical cluster analysis showed that the combination of miR-1, -133a, and -126 in UA and of miR-1, -126, and -485-3p in SA correctly classified patients vs. controls with an efficiency ≥ 87%. No combination of miRNAs was able to reliably discriminate patients with UA from patients with SA. Conclusions This work showed that specific plasmatic miRNA signatures have the potential to accurately discriminate patients with angiographically documented CAD from matched controls. We failed to identify a plasmatic miRNA expression pattern capable to differentiate SA from UA patients. PMID:24260372

Differential structural status of the RNA counterpart of an undecamer quasi-palindromic DNA sequence present in LCR of human β-globin gene cluster.

Science.gov (United States)

Kaushik, Mahima; Kukreti, Shrikant

2015-01-01

Our previous work on structural polymorphism shown at a single nucleotide polymorphism (SNP) (A → G) site located on HS4 region of locus control region (LCR) of β-globin gene has established a hairpin → duplex equilibrium corresponding to A → B like DNA transition (Kaushik M, Kukreti, R., Grover, D., Brahmachari, S.K. and Kukreti S. Nucleic Acids Res. 2003; Kaushik M, Kukreti S. Nucleic Acids Res. 2006). The G-allele of A → G SNP has been shown to be significantly associated with the occurrence of β-thalassemia. Considering the significance of this 11-nt long quasi-palindromic sequence [5'-TGGGG(G/A)CCCCA; HP(G/A)11] of β-globin gene LCR, we further explored the differential behavior of the same DNA sequence with its RNA counterpart, using various biophysical and biochemical techniques. In contrast to its DNA counterpart exhibiting a A → B structural transition and an equilibrium between duplex and hairpin forms, the studied RNA oligonucleotide sequence [5'-UGGGG(G/A)CCCCA; RHP(G/A)11] existed only in duplex form (A-conformation) and did not form hairpin. The single residue difference from A to G led to the unusual thermal stability of the RNA structure formed by the studied sequence. Since, naturally occurring mutations and various SNP sites may stabilize or destabilize the local DNA/RNA secondary structures, these structural transitions may affect the gene expression by a change in the protein-DNA recognition patterns.

Stable RNA interference of ErbB-2 gene synergistic with epirubicin suppresses breast cancer growth in vitro and in vivo

International Nuclear Information System (INIS)

Hu Xiaoqu; Su Fengxi; Qin Li; Jia Weijuan; Gong Chang; Yu Fengyan; Guo Jujiang; Song Erwei

2006-01-01

Overexpression of human epidermal growth factor receptor-2 (Her2, ErbB-2) contributes to the progression and metastasis of breast cancer, implying that Her2 gene is a suitable target of RNA interference (RNAi) for breast cancer therapy. Here, we employed plasmid-mediated expression of 2 different Her2-shRNAs (pU6-Her2shRNAs) efficiently silenced the target gene expression on Her2 expressing SKBR-3 breast cancer cells in both mRNA and protein levels. Consequently, pU6-Her2shRNA increased apoptosis and reduced proliferation of SKBR-3 cells assayed by TUNEL and MTT, respectively. In vivo, intra-tumor injection of pU6-Her2shRNA inhibited the growth of SKBR-3 tumors inoculated subcutaneously in nude mice. Furthermore, pU6-Her2shRNA synergized the tumor suppression effect of epirubicin to SKBR-3 cells in vitro and implanted subcutaneously in nude mice. Therefore, we concluded that stable silencing of Her2 gene expression with plasmid expressing shRNA may hold great promise as a novel therapy for Her2 expressing breast cancers alone or in combination with anthracycline chemotherapy

Characterization of microstructure and texture across dissimilar super duplex/austenitic stainless steel weldment joint by super duplex filler metal

Energy Technology Data Exchange (ETDEWEB)

Eghlimi, Abbas, E-mail: a.eghlimi@ma.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Shamanian, Morteza [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Eskandarian, Masoomeh [Department of Materials Engineering, Shiraz University, Shiraz 71348-51154 (Iran, Islamic Republic of); Zabolian, Azam [Department of Natural Resources, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Szpunar, Jerzy A. [Department of Mechanical Engineering, University of Saskatchewan, Saskatoon SK S7N 5A9 (Canada)

2015-08-15

In the present paper, microstructural changes across an as-welded dissimilar austenitic/duplex stainless steel couple welded by a super duplex stainless steel filler metal using gas tungsten arc welding process is characterized with optical microscopy and electron back-scattered diffraction techniques. Accordingly, variations of microstructure, texture, and grain boundary character distribution of base metals, heat affected zones, and weld metal were investigated. The results showed that the weld metal, which was composed of Widmanstätten austenite side-plates and allotriomorphic grain boundary austenite morphologies, had the weakest texture and was dominated by low angle boundaries. The welding process increased the ferrite content but decreased the texture intensity at the heat affected zone of the super duplex stainless steel base metal. In addition, through partial ferritization, it changed the morphology of elongated grains of the rolled microstructure to twinned partially transformed austenite plateaus scattered between ferrite textured colonies. However, the texture of the austenitic stainless steel heat affected zone was strengthened via encouraging recrystallization and formation of annealing twins. At both interfaces, an increase in the special character coincident site lattice boundaries of the primary phase as well as a strong texture with <100> orientation, mainly of Goss component, was observed. - Graphical abstract: Display Omitted - Highlights: • Weld metal showed local orientation at microscale but random texture at macroscale. • Intensification of <100> orientated grains was observed adjacent to the fusion lines. • The austenite texture was weaker than that of the ferrite in all duplex regions. • Welding caused twinned partially transformed austenites to form at SDSS HAZ. • At both interfaces, the ratio of special CSL boundaries of the primary phase increased.

Analyzing the Potential of Full Duplex in 5G Ultra-Dense Small Cell Networks

DEFF Research Database (Denmark)

Gatnau, Marta; Berardinelli, Gilberto; Mahmood, Nurul Huda

2016-01-01

Full duplex technology has become an attractive solution for future 5th Generation (5G) systems for accommodating the exponentially growing mobile traffic demand. Full duplex allows a node to transmit and receive simultaneously in the same frequency band, thus, theoretically, doubling the system...... throughput over conventional half duplex systems. A key limitation in building a feasible full duplex node is the self-interference, i.e., the interference generated by the transmitted signal to the desired signal received on the same node. This constraint has been overcome given the recent advances...... in the self-interference cancellation technology. However, there are other limitations in achieving the theoretical full duplex gain: residual self-interference, traffic constraints and inter-cell and intra-cell interference. The contribution of this article is twofold. Firstly, achievable levels of self...

Duplex-tube sodium-indication steam generator

International Nuclear Information System (INIS)

Matal, O.; Martoch, J.

1984-01-01

The steam generator with duplex tubes and sodium indication is connected to the main sodium input and output via the inlet and outlet chambers and has indication spaces connected to the interspaces of the duplex tubes. The first indication space is linked with the auxiliary inlet pipe to the inlet chamber and the second indication space is connected with the auxiliary pipe to the outlet chamber. Mounted to the auxiliary inlet pipe is at least one closure, i.e., a valve or electromagnetic stop. Mounted on the auxiliary outlet pipe is an indication sensor, e.g., a sodium flow sensor. At least one indication space is provided with an alarm sensor, e.g., a thermocouple, a pressure gauge and one sensor to monitor the hydrogen content of sodium. (J.P.)

The value and economic analysis of routine postoperative carotid duplex ultrasound surveillance after carotid endarterectomy.

Science.gov (United States)

AbuRahma, Ali F; Srivastava, Mohit; AbuRahma, Zachary; Jackson, Will; Mousa, Albeir; Stone, Patrick A; Dean, L Scott; Green, Jason

2015-08-01

Several studies have reported on the role of postoperative duplex ultrasound surveillance after carotid endarterectomy (CEA) with varying results. Most of these studies had a small sample size or did not analyze cost-effectiveness. We analyzed 489 of 501 CEA patients with patch closure. All patients had immediate postoperative duplex ultrasound examination and were routinely followed up both clinically and with duplex ultrasound at regular intervals of 1 month, 6 months, 12 months, and every 12 months thereafter. A Kaplan-Meier analysis was used to estimate the rate of ≥50% and ≥80% post-CEA restenosis over time and the time frame of progression from normal to ≥50% or ≥80% restenosis. The cost of post-CEA duplex surveillance was also estimated. Overall, 489 patients with a mean age of 68.5 years were analyzed. Ten of these had residual postoperative ≥50% stenosis, and 37 did not undergo a second duplex ultrasound examination and therefore were not included in the final analysis. The mean follow-up was 20.4 months (range, 1-63 months), with a mean number of duplex ultrasound examinations of 3.6 (range, 1-7). Eleven of 397 patients (2.8%) with a normal finding on immediate postoperative duplex ultrasound vs 4 of 45 (8.9%) with mild stenosis on immediate postoperative duplex ultrasound progressed to ≥50% restenosis (P = .055). Overall, 15 patients (3.1%) had ≥50% restenosis, 9 with 50% to duplex ultrasound), which equals $1,408,320, to detect only four patients with ≥80% to 99% restenosis who may have been potential candidates for reintervention. This study shows that the value of routine postoperative duplex ultrasound surveillance after CEA with patch closure may be limited, particularly if the finding on immediate postoperative duplex ultrasound is normal or shows minimal disease. Copyright © 2015 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Crystallization and X-ray diffraction analysis of the Trp/amber editing site of hepatitis delta virus (+)RNA: a case of rational design

International Nuclear Information System (INIS)

MacElrevey, Celeste; Wedekind, Joseph E.

2005-01-01

Well diffracting decamer crystals of the hepatitis delta virus RNA-editing site were prepared, but exhibited merohedral twinning and base averaging owing to duplex symmetry. A longer asymmetric construct that includes additional flanking RNA sequences has been crystallized that does not appear to exhibit these defects. RNA editing by mammalian ADAR1 (Adenosine Deaminase Acting on RNA) is required for the life cycle of the hepatitis delta virus (HDV). Editing extends the single viral open reading frame to yield two protein products of alternate length. ADARs are believed to recognize double-stranded RNA substrates via a ‘structure-based’ readout mechanism. Crystals of 10-mer duplexes representing the HDV RNA-editing site diffracted to 1.35 Å resolution, but suffered from merohedral twinning and averaging of the base registry. Expansion of the construct to include two flanking 3 × 1 internal loops yielded crystals in the primitive tetragonal space group P4 1 2 1 2 or P4 3 2 1 2. X-ray diffraction data were collected to 2.8 Å resolution, revealing a unit cell with parameters a = 62.5, c = 63.5 Å. The crystallization and X-ray analysis of multiple forms of the HDV RNA-editing substrate, encounters with common RNA crystal-growth defects and a strategy to overcome these problems are reported

Impact of Duplex arterial mapping on decision making in non-acute ischemic limb patients.

Science.gov (United States)

Elbadawy, A; Aly, H; Ibrahim, M; Bakr, H

2015-12-01

The aim of this study was to demonstrate the impact of Duplex arterial mapping on decision making in non-acute ischemic limb patient group reporting pain onset between 15 days and 3 months. We prospectively evaluated patients presented with critical limb ischemia who reported pain onset of duration between 15 days and 3 months in one-year period. Our series included thirty cases (mean age=61.3 years old), as Duplex arterial mapping was the sole preoperative imaging tool performed in all of them. All patients, in whom duplex indicated thrombosis in long occluded segments, were candidates for fluoroscopically guided thrombectomy. When Duplex defined chronic arterial occlusions, patients underwent endovascular or bypass revascularisation procedures. Impact of Duplex wall interrogation on decision-making between the two groups (subacute and chronic) was measured. Duplex arterial mapping categorized correctly all 30 patients into either subacute ischemia with removable clot (N.=14) or chronic ischemia (N.=16). Fluoroscopic guided thrombectomy was performed in 14 cases when Duplex advised long occluded arterial segments as indicted by intact intima with echogenic thrombus inside. Bypass surgery was performed in 8 patients. Percutaneous transluminal angioplasty (PTA) was done in 7 cases and thrombendartrectomy of common femoral artery in a single case. One-year patency rate in our series was 86.6%. It was 71.4% in thrombosis group. Limb salvage rate was 93.3%. Duplex arterial mapping could be used to differentiate the subacute ischemia with removable thrombus and chronic arterial occlusions guiding for the best revascularization procedure accordingly.

On the Potential of Full Duplex Performance in 5G Ultra-Dense Small Cell Networks

DEFF Research Database (Denmark)

Gatnau, Marta; Fleischer, Marko; Berardinelli, Gilberto

2016-01-01

inter-cell interference and traffic constraints. In this paper, we first study the self-interference cancellation capabilities by using a real demonstrator. Results show that achieving ~110 dB of cancellation is already possible with the current available technology, thus providing the required level...... of isolation to build an operational full duplex node. Secondly, we investigate the inter-cell interference and traffic constraints impact on the full duplex performance in 5th generation systems. System level results show that both the traffic and the inter-cell interference can significantly reduce...... the potential gain of full duplex with respect to half duplex. However, for large traffic asymmetry, full duplex can boost the performance of the lightly loaded link....

Detection of Sialic Acid-Utilising Bacteria in a Caecal Community Batch Culture Using RNA-Based Stable Isotope Probing

Directory of Open Access Journals (Sweden)

Wayne Young

2015-03-01

Full Text Available Sialic acids are monosaccharides typically found on cell surfaces and attached to soluble proteins, or as essential components of ganglioside structures that play a critical role in brain development and neural transmission. Human milk also contains sialic acid conjugated to oligosaccharides, glycolipids, and glycoproteins. These nutrients can reach the large bowel where they may be metabolised by the microbiota. However, little is known about the members of the microbiota involved in this function. To identify intestinal bacteria that utilise sialic acid within a complex intestinal community, we cultured the caecal microbiota from piglets in the presence of 13C-labelled sialic acid. Using RNA-based stable isotope probing, we identified bacteria that consumed 13C-sialic acid by fractionating total RNA in isopycnic buoyant density gradients followed by 16S rRNA gene analysis. Addition of sialic acid caused significant microbial community changes. A relative rise in Prevotella and Lactobacillus species was accompanied by a corresponding reduction in the genera Escherichia/Shigella, Ruminococcus and Eubacterium. Inspection of isotopically labelled RNA sequences suggests that the labelled sialic acid was consumed by a wide range of bacteria. However, species affiliated with the genus Prevotella were clearly identified as the most prolific users, as solely their RNA showed significantly higher relative shares among the most labelled RNA species. Given the relevance of sialic acid in nutrition, this study contributes to a better understanding of their microbial transformation in the intestinal tract with potential implications for human health.

THE INFLUENCE OF POSTHEAT TREATMENT ON FERRITE REDISTRIBUTION IN DUPLEX STEELS ELECTRON BEAM WELDS

Directory of Open Access Journals (Sweden)

Zita Iždinská

2009-04-01

Full Text Available The duplex stainless steel is two-phase steel with the structure composed of austenite and ferrite with optimum austenite/ferrite proportion 50%. At present, classical arc processes for welding duplex steels are generally regarded as acceptable. On the other hand electron and laser beam welding is up to now considered less suitable for welding duplex steels. The submitted work presents the results of testing various thermal conditions at welding duplex stainless steel with electron beam. It was shown, that application of suitable postheat made possible to reduce the ferrite content in weld metal.

Quality assurance of lower limb venous duplex scans performed by vascular surgeons.

Science.gov (United States)

Kordowicz, A; Ferguson, G; Salaman, R; Onwudike, M

2015-02-01

Duplex scanning is the gold standard for investigating venous reflux; increasingly surgeons perform these scans themselves. There has been no data published analysing the accuracy of Duplex scans performed by vascular surgeons. We aimed to evaluate an objective method of comparing the results of lower limb Duplex scans performed by one consultant vascular surgeon with those performed by a vascular technologist. We assessed 100 legs with symptomatic varicose veins. Each patient underwent two lower limb venous Duplex scans; one performed by a consultant vascular surgeon and one by a vascular technologist. Scan results were randomised and sent to two consultant vascular surgeons blinded to the identity and experience of the sonographer. They were asked to recommend treatment. A k score was calculated in each case to assess the level of agreement between the scans performed by the consultant and the technologist. Eighty-one patients were studied (53 females). The kappa score for assessor 1 was 0.60 (95%CI:0.44-0.75) and for assessor 2 was 0.62 (95%CI:0.48-0.75). k scores >0.60 represent a substantial strength of agreement. Duplex scans performed by this surgeon were comparable to those performed by a vascular technologist. It is possible to quality-assure duplex performed by vascular surgeons without directly observing the scanning process or reviewing digitally recorded images. We propose standardisation of training, assessment and quality assurance for vascular surgeons wishing to perform ultrasound scans.

Selection of patients with infrainguinal arterial occlusive disease for percutaneous transluminal angioplasty with duplex scanning

International Nuclear Information System (INIS)

Bostroem Ardin, A.; Hellberg, A.; Ljungman, C.; Logason, K.; Karacagil, S.; Loefberg, A.M.; Andren, B.

2002-01-01

Aim: To evaluate the role of duplex scanning in the selection of patients with infrainguinal arterial occlusive disease for percutaneous transluminal angioplasty (PTA). Material and Methods: From January 1995 through May 2000, 702 patients (952 limbs), with chronic lower extremity ischemia due to infrainguinal atherosclerotic disease diagnosed by duplex scanning, were retrospectively studied. Diagnostic angiography (130 limbs) or infrainguinal PTA (108 limbs) was performed in 238 limbs. Two investigators retrospectively analyzed the duplex examinations and angiographies in a blinded manner and used similar criteria for the interpretation of lesions suitable or not suitable for PTA. Results: The superficial femoral, popliteal and crural artery lesions were correctly selected for PTA in 85%, 66% and 32%, respectively. The accuracy, sensitivity, specificity, negative predictive value and positive predictive value of duplex scanning to appropriately categorize femoropopliteal lesions as suitable or unsuitable for PTA were 89%, 83%, 92%, 94% and 78%, respectively. The accuracy of duplex scanning for predicting the performance of infrainguinal PTA was 83%. Conclusion: Duplex scanning has an important impact on the selection of treatment modalities in limbs with infrainguinal arterial occlusive disease. Femoropopliteal lesions can be reliably selected to PTA according to duplex scan findings

Duplex evaluation following femoropopliteal angioplasty and stenting: criteria and utility of surveillance.

Science.gov (United States)

Baril, Donald T; Marone, Luke K

2012-07-01

Surveillance following lower extremity bypass, carotid endarterectomy, and endovascular aortic aneurysm repair has become the standard of care at most institutions. Conversely, surveillance following lower extremity endovascular interventions is performed somewhat sporadically in part because the duplex criteria for recurrent stenoses have been ill defined. It appears that duplex surveillance after peripheral endovascular interventions, as with conventional bypass, is beneficial in identifying recurrent lesions which may preclude failure and occlusion. In-stent stenosis following superficial femoral artery angioplasty and stenting can be predicted by both peak systolic velocity and velocity ratio data as measured by duplex ultrasound. Duplex criteria have been defined to determine both ≥50% in-stent stenosis and ≥80% in-stent stenosis. Although not yet well studied, it appears that applying these criteria during routine surveillance may assist in preventing failure of endovascular interventions.

Templated Chemistry for Sequence-Specific Fluorogenic Detection of Duplex DNA

Science.gov (United States)

Li, Hao; Franzini, Raphael M.; Bruner, Christopher; Kool, Eric T.

2015-01-01

We describe the development of templated fluorogenic chemistry for detection of specific sequences of duplex DNA in solution. In this approach, two modified homopyrimidine oligodeoxynucleotide probes are designed to bind by triple helix formation at adjacent positions on a specific purine-rich target sequence of duplex DNA. One fluorescein-labeled probe contains an α-azidoether linker to a fluorescence quencher; the second (trigger) probe carries a triarylphosphine, designed to reduce the azide and cleave the linker. The data showed that at pH 5.6 these probes yielded a strong fluorescence signal within minutes on addition to a complementary homopurine duplex DNA target. The signal increased by a factor of ca. 60, and was completely dependent on the presence of the target DNA. Replacement of cytosine in the probes with pseudoisocytosine allowed the templated chemistry to proceed readily at pH 7. Single nucleotide mismatches in the target oligonucleotide slowed the templated reaction considerably, demonstrating high sequence selectivity. The use of templated fluorogenic chemistry for detection of duplex DNAs has not been previously reported and may allow detection of double stranded DNA, at least for homopurine-homopyrimidine target sites, under native, non-disturbing conditions. PMID:20859985

Podiatry Ankle Duplex Scan: Readily Learned and Accurate in Diabetes.

Science.gov (United States)

Normahani, Pasha; Powezka, Katarzyna; Aslam, Mohammed; Standfield, Nigel J; Jaffer, Usman

2018-03-01

We aimed to train podiatrists to perform a focused duplex ultrasound scan (DUS) of the tibial vessels at the ankle in diabetic patients; podiatry ankle (PodAnk) duplex scan. Thirteen podiatrists underwent an intensive 3-hour long simulation training session. Participants were then assessed performing bilateral PodAnk duplex scans of 3 diabetic patients with peripheral arterial disease. Participants were assessed using the duplex ultrasound objective structured assessment of technical skills (DUOSATS) tool and an "Imaging Score". A total of 156 vessel assessments were performed. All patients had abnormal waveforms with a loss of triphasic flow. Loss of triphasic flow was accurately detected in 145 (92.9%) vessels; the correct waveform was identified in 139 (89.1%) cases. Participants achieved excellent DUOSATS scores (median 24 [interquartile range: 23-25], max attainable score of 26) as well as "Imaging Scores" (8 [8-8], max attainable score of 8) indicating proficiency in technical skills. The mean time taken for each bilateral ankle assessment was 20.4 minutes (standard deviation ±6.7). We have demonstrated that a focused DUS for the purpose of vascular assessment of the diabetic foot is readily learned using intensive simulation training.

Toughness and other mechanical properties of the duplex stainless steel 2205

International Nuclear Information System (INIS)

Sieurin, H.; Sandstroem, R.

2003-01-01

The use and range of potential applications of duplex stainless steel continuously increase. An overview of the mechanical properties of duplex stainless steel 2205 is presented with focus on toughness properties. Impact and fracture toughness as well as strength results from the European research project, EcoPress, are presented. (orig.)

An albumin-mediated cholesterol design-based strategy for tuning siRNA pharmacokinetics and gene silencing

DEFF Research Database (Denmark)

Bienk, Konrad; Hvam, Michael Lykke; Pakula, Malgorzata Maria

2016-01-01

/2 12 min (naked) to t1/2 45 min (single cholesteryl) and t1/2 71 min (double cholesteryl) using fluorescent live bioimaging. The biodistribution showed increased accumulation in the liver for the double cholesteryl modified siRNA that correlated with an increase in hepatic Factor VII gene silencing......HSA/siRNA complex exhibited reduced nuclease degradation and reduced induction of TNF-α production by human peripheral blood mononuclear cells. The increased solubility of heavily cholesteryl modified siRNA in the presence of rHSA facilitated duplex annealing and consequent interaction that allowed in vivo studies...

Effects of trimethylamine N-oxide and urea on DNA duplex and G-quadruplex.

Science.gov (United States)

Ueda, Yu-Mi; Zouzumi, Yu-Ki; Maruyama, Atsushi; Nakano, Shu-Ichi; Sugimoto, Naoki; Miyoshi, Daisuke

2016-01-01

We systematically investigated effects of molecular crowding with trimethylamine N -oxide (TMAO) as a zwitterionic and protective osmolyte and urea as a nonionic denaturing osmolyte on conformation and thermodynamics of the canonical DNA duplex and the non-canonical DNA G-quadruplex. It was found that TMAO and urea stabilized and destabilized, respectively, the G-quadruplex. On the other hand, these osmolytes generally destabilize the duplex; however, it was observed that osmolytes having the trimethylamine group stabilized the duplex at the lower concentrations because of a direct binding to a groove of the duplex. These results are useful not only to predict DNA structures and their thermodynamics under physiological environments in living cells, but also design of polymers and materials to regulate structure and stability of DNA sequences.

Influence of the filler material on the pitting corrosion in welded duplex stainless

International Nuclear Information System (INIS)

Munez, C. J.; Utrilla, M. V.; Urena, A.; Otero, E.

2007-01-01

In this work, it has been studied the pitting corrosion resistance of welding duplex stainless steel 2205. Unions were made by GMAW process with different fillers: duplex ER 2209 and two austenitic (ER 316LSi and ER 308LSi). the microstructure obtained with the duplex ER 2209 filler is similar to the duplex 2205 base material, but the unions produced with the austenitic fillers cause a decrease of the phases relationα/γ. To evaluate the influence of the filler on the weld, the pitting corrosion resistance was determined by electrochemical critical pitting temperature test (TCP) and the mechanical properties by the hardness. The phases imbalance produced for the dissimilar fillers bring out a variation of the pitting corrosion resistance and the mechanical properties. (Author)

Duplex sonography of the near-surface leg veins

International Nuclear Information System (INIS)

Mendoza, E.

2007-01-01

The book contains the following contributions: The ultrasonograph, selection of the ultrasonic transducer, anatomy of the near-surface vein system, physiology of the near-surface vein system, varicose status classification, systematics of the duplex sonography of near-surface leg veins, provocational maneuver for the duplex sonographic varicose diagnostics, exploration of vena saphena parva, perforans veins, side branches, phlebitis, sonography for varicose therapy, postsurgical sonography, deep leg veins, examination of near-surface leg veins for the pathology of the deep vein system, differential diagnostic clarification of leg oedema from the phlebologic-lymphological view, diagnostic side features along the near-surface leg veins

Enhancement of allele discrimination by introduction of nucleotide mismatches into siRNA in allele-specific gene silencing by RNAi.

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Yusuke Ohnishi

Full Text Available Allele-specific gene silencing by RNA interference (RNAi is therapeutically useful for specifically inhibiting the expression of disease-associated alleles without suppressing the expression of corresponding wild-type alleles. To realize such allele-specific RNAi (ASP-RNAi, the design and assessment of small interfering RNA (siRNA duplexes conferring ASP-RNAi is vital; however, it is also difficult. In a previous study, we developed an assay system to assess ASP-RNAi with mutant and wild-type reporter alleles encoding the Photinus and Renilla luciferase genes. In line with experiments using the system, we realized that it is necessary and important to enhance allele discrimination between mutant and corresponding wild-type alleles. Here, we describe the improvement of ASP-RNAi against mutant alleles carrying single nucleotide variations by introducing base substitutions into siRNA sequences, where original variations are present in the central position. Artificially mismatched siRNAs or short-hairpin RNAs (shRNAs against mutant alleles of the human Prion Protein (PRNP gene, which appear to be associated with susceptibility to prion diseases, were examined using this assessment system. The data indicates that introduction of a one-base mismatch into the siRNAs and shRNAs was able to enhance discrimination between the mutant and wild-type alleles. Interestingly, the introduced mismatches that conferred marked improvement in ASP-RNAi, appeared to be largely present in the guide siRNA elements, corresponding to the 'seed region' of microRNAs. Due to the essential role of the 'seed region' of microRNAs in their association with target RNAs, it is conceivable that disruption of the base-pairing interactions in the corresponding seed region, as well as the central position (involved in cleavage of target RNAs, of guide siRNA elements could influence allele discrimination. In addition, we also suggest that nucleotide mismatches at the 3'-ends of sense

Duplex Healing of Selectively Thiolated Guanosine Mismatches through a Cd2+ Chemical Stimulus.

Science.gov (United States)

Lunn, Samantha M L; Hribesh, Samira; Whitfield, Colette J; Hall, Michael J; Houlton, Andrew; Bronowska, Agnieszka K; Tuite, Eimer M; Pike, Andrew R

2018-03-25

The on-column selective conversion of guanosine to thioguanosine (tG) yields modified oligomers that exhibit destabilisation over the fully complementary duplex. Restoration to a stabilised duplex is induced through thio-directed Cd 2+ coordination; a route for healing DNA damage. Short oligomers are G-specifically thiolated through a modified on-column protocol without the need for costly thioguanosine phosphoramidites. Addition of Cd 2+ ions to a duplex containing a highly disrupted tG central mismatch sequence, 3'-A 6 tG 4 T 6 -5', suggests a (tG) 8 Cd 2 central coordination regime, resulting in increased base stacking and duplex stability. Equilibrium molecular dynamic calculations support the hypothesis of metal-induced healing of the thiolated duplex. The 2 nm displacement of the central tG mismatched region is dramatically reduced after the addition of a chemical stimuli, Cd 2+ ions, returning to a minimized fluctuational state comparable to the unmodified fully complementary oligomer. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Structural Overview of RNA-Dependent RNA Polymerases from the Flaviviridae Family

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Jiqin Wu

2015-06-01

Full Text Available RNA-dependent RNA polymerases (RdRPs from the Flaviviridae family are representatives of viral polymerases that carry out RNA synthesis through a de novo initiation mechanism. They share a ≈ 600-residue polymerase core that displays a canonical viral RdRP architecture resembling an encircled right hand with palm, fingers, and thumb domains surrounding the active site. Polymerase catalytic motifs A–E in the palm and motifs F/G in the fingers are shared by all viral RdRPs with sequence and/or structural conservations regardless of the mechanism of initiation. Different from RdRPs carrying out primer-dependent initiation, Flaviviridae and other de novo RdRPs utilize a priming element often integrated in the thumb domain to facilitate primer-independent initiation. Upon the transition to the elongation phase, this priming element needs to undergo currently unresolved conformational rearrangements to accommodate the growth of the template-product RNA duplex. In the genera of Flavivirus and Pestivirus, the polymerase module in the C-terminal part of the RdRP protein may be regulated in cis by the N-terminal region of the same polypeptide. Either being a methyltransferase in Flavivirus or a functionally unclarified module in Pestivirus, this region could play auxiliary roles for the canonical folding and/or the catalysis of the polymerase, through defined intra-molecular interactions.

Enhanced sensitivity of DNA- and rRNA-based stable isotope probing by fractionation and quantitative analysis of isopycnic centrifugation gradients.

Science.gov (United States)

Lueders, Tillmann; Manefield, Mike; Friedrich, Michael W

2004-01-01

Stable isotope probing (SIP) of nucleic acids allows the detection and identification of active members of natural microbial populations that are involved in the assimilation of an isotopically labelled compound into nucleic acids. SIP is based on the separation of isotopically labelled DNA or rRNA by isopycnic density gradient centrifugation. We have developed a highly sensitive protocol for the detection of 'light' and 'heavy' nucleic acids in fractions of centrifugation gradients. It involves the fluorometric quantification of total DNA or rRNA, and the quantification of either 16S rRNA genes or 16S rRNA in gradient fractions by real-time PCR with domain-specific primers. Using this approach, we found that fully 13C-labelled DNA or rRNA of Methylobacterium extorquens was quantitatively resolved from unlabelled DNA or rRNA of Methanosarcina barkeri by cesium chloride or cesium trifluoroacetate density gradient centrifugation respectively. However, a constant low background of unspecific nucleic acids was detected in all DNA or rRNA gradient fractions, which is important for the interpretation of environmental SIP results. Consequently, quantitative analysis of gradient fractions provides a higher precision and finer resolution for retrieval of isotopically enriched nucleic acids than possible using ethidium bromide or gradient fractionation combined with fingerprinting analyses. This is a prerequisite for the fine-scale tracing of microbial populations metabolizing 13C-labelled compounds in natural ecosystems.

Breaking the Transmitter-Receiver Isolation Barrier in Mobile Handsets with Spatial Duplexing

DEFF Research Database (Denmark)

Alrabadi, Osama; Tatomirescu, Alexandru; Knudsen, Mikael

2013-01-01

In full-duplex radio communication systems like eUTRAN, CDMA-2000, the radio transmitter (Tx) is active at the same time as the radio receiver (Rx). The Tx and the Rx will be using separate dedicated frequency bands and the Tx-Rx isolation is ensured by duplex filters. However, agile duplexers...... required for multiband operation are almost non-existent while dedicating a bank of narrowband filters is bulky and incurs considerable switching losses. In this article we propose an approach that dramatically reduces the complexity of the RF frontend, first by replacing the duplex filter with a spatial...... frequency bands as long as the antennas are made tunable. Moreover, the spatial filter may directly benefit from the balanced architecture of the power amplifiers (PAs) thus reducing the total system complexity and insertion loss. Finally, simulation and initial measurement results are provided...

Can Full Duplex reduce the discovery time in D2D Communication?

DEFF Research Database (Denmark)

Gatnau, Marta; Berardinelli, Gilberto; Mahmood, Nurul Huda

2016-01-01

Device-to-device (D2D) communication is considered as one of the key technologies to support new types of services, such as public safety and proximity-based applications. D2D communication requires a discovery phase, i.e., the node awareness procedure prior to the communication phase. Conventional...... half duplex transmission may not be sufficient to provide fast discovery and cope with the strict latency targets of future 5G services. On the other hand, in-band full duplex, by allowing simultaneous transmission and reception, may complete the discovery phase faster. In this paper, the potential...... of full duplex in providing fast discovery for the next 5th generation (5G) system supporting D2D communication is investigated. A design for such system is presented and evaluated via simulations, showing that full duplex can accelerate the discovery phase by supporting a higher transmission probability...

On full duplex Gaussian relay channels with self-interference

KAUST Repository

Behboodi, Arash

2016-08-15

Self interference (SI) in full duplex (FD) systems is the interference caused by the transmission stream on the reception stream. Being one of the main restrictive factors for performance of practical full duplex systems, however, not too much is known about its effect on the fundamental limits of relaying systems. In this work, we consider the full duplex three-node relay channel with SI where SI is modeled as an additive Gaussian noise whose variance is dependent on instantaneous input power. The classical achievable rates and upper bounds for the single three-node relay channel no longer apply due to the structure of SI. Achievable rates for Decode-and-Forward (DF) and Compress-and-Forward (CF) and upper bounds on the capacity are derived assuming Gaussian inputs and SI. The deterministic model is also introduced and its capacity is characterized. The optimal joint source-relay distributions is discussed. Numerical results are provided comparing the achievable rates and upper bound. © 2016 IEEE.

Duplex recombinase polymerase amplification assays incorporating competitive internal controls for bacterial meningitis detection.

Science.gov (United States)

Higgins, Owen; Clancy, Eoin; Forrest, Matthew S; Piepenburg, Olaf; Cormican, Martin; Boo, Teck Wee; O'Sullivan, Nicola; McGuinness, Claire; Cafferty, Deirdre; Cunney, Robert; Smith, Terry J

2018-04-01

Recombinase polymerase amplification (RPA) is an isothermal nucleic acid amplification technology that provides rapid and robust infectious disease pathogen detection, ideal for point-of-care (POC) diagnostics in disease-prevalent low-resource countries. We have developed and evaluated three duplex RPA assays incorporating competitive internal controls for the detection of leading bacterial meningitis pathogens. Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae singleplex RPA assays were initially developed and evaluated, demonstrating 100% specificity with limits of detection of 4.1, 8.5 and 3.9 genome copies per reaction, respectively. Each assay was further developed into internally controlled duplex RPA assays via the incorporation of internal amplification control templates. Clinical performance of each internally controlled duplex RPA assay was evaluated by testing 64 archived PCR-positive clinical samples. Compared to real-time PCR, all duplex RPA assays demonstrated 100% diagnostic specificity, with diagnostic sensitivities of 100%, 86.3% and 100% for the S. pneumoniae, N. meningitidis and H. influenzae assays, respectively. This study details the first report of internally controlled duplex RPA assays for the detection of bacterial meningitis pathogens: S. pneumoniae, N. meningitidis and H. influenzae. We have successfully demonstrated the clinical diagnostic utility of each duplex RPA assay, introducing effective diagnostic technology for POC bacterial meningitis identification in disease-prevalent developing countries. Copyright © 2018 Elsevier Inc. All rights reserved.

Tricriticality in the q-neighbor Ising model on a partially duplex clique.

Science.gov (United States)

Chmiel, Anna; Sienkiewicz, Julian; Sznajd-Weron, Katarzyna

2017-12-01

We analyze a modified kinetic Ising model, a so-called q-neighbor Ising model, with Metropolis dynamics [Phys. Rev. E 92, 052105 (2015)PLEEE81539-375510.1103/PhysRevE.92.052105] on a duplex clique and a partially duplex clique. In the q-neighbor Ising model each spin interacts only with q spins randomly chosen from its whole neighborhood. In the case of a duplex clique the change of a spin is allowed only if both levels simultaneously induce this change. Due to the mean-field-like nature of the model we are able to derive the analytic form of transition probabilities and solve the corresponding master equation. The existence of the second level changes dramatically the character of the phase transition. In the case of the monoplex clique, the q-neighbor Ising model exhibits a continuous phase transition for q=3, discontinuous phase transition for q≥4, and for q=1 and q=2 the phase transition is not observed. On the other hand, in the case of the duplex clique continuous phase transitions are observed for all values of q, even for q=1 and q=2. Subsequently we introduce a partially duplex clique, parametrized by r∈[0,1], which allows us to tune the network from monoplex (r=0) to duplex (r=1). Such a generalized topology, in which a fraction r of all nodes appear on both levels, allows us to obtain the critical value of r=r^{*}(q) at which a tricriticality (switch from continuous to discontinuous phase transition) appears.

Magnetic resonance urography in duplex kidney with ectopic ureteral insertion

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Conjeevaram Rajendrarao Thambidorai

2011-01-01

Full Text Available This is a report on the use of magnetic resonance urography (MRU in a 6-year-old girl who presented with urinary incontinence. She had a left duplex kidney with poorly functioning upper moiety and ectopic insertion of the dilated upper pole ureter. MRU has been shown to be superior to conventional imaging techniques in delineating poorly functioning moieties of duplex kidneys and ectopic ureters.

Venous filling time using air-plethysmography correlates highly with great saphenous vein reflux time using duplex.

Science.gov (United States)

Lattimer, C R; Azzam, M; Kalodiki, E; Geroulakos, G

2014-03-01

Venous filling time (VFT90) is the time taken to reach 90% of the venous volume in the calf. It is recorded by air-plethysmography (APG(®)) and is assumed to measure global venous reflux duration. However, this has never been confirmed by duplex. The aim of the study was to compare VFT on APG to venous reflux time/duration (RT) measured simultaneously with duplex on the same patients. Twenty-six consecutive patients, M:F = 16:10, age (25-78), C1 = 1, C2 = 4, C3 = 8, C4a = 6, C4b = 4, C5 = 2, C6 = 1, underwent simultaneous APG with duplex. The venous filling index (VFI, mL/second), VFT90 (seconds), great saphenous vein (GSV) RT on duplex, averaged thigh GSV diameter and thigh length (length) between the APG sensor air-cuff and duplex transducer were recorded. The VFT100 was calculated by VFT90/0.9. The additional time taken to fill the thigh was achieved using the VFI, length and deep vein diameter (d), to determine the corrected reflux duration: CRD = VFT100 + (length × πd(2)/4 (1/VFI)). Twenty-five patients are presented. One patient with very mild reflux (VFT90 = 55.9 seconds) had an indeterminate endpoint on duplex and was excluded. The median (range) VFI and GSV diameter was 4.9(1.3-15.5) mL/second and 7(4-17) mm, respectively. The VFT90 and VFT100 both correlated with RT on duplex (Spearman, P duplex RT at 24 (16.9) versus 28 (20) seconds respectively, P duplex by performing simultaneous measurements. There was an excellent correlation between the VFT90 versus duplex RT, thereby comparing reverse flow in a single superficial vein against the legs overall venous haemodynamic status. These tests can both be used in the quantification of reflux.

Evaluation of Microstructure and Mechanical Properties in Dissimilar Austenitic/Super Duplex Stainless Steel Joint

Science.gov (United States)

Rahmani, Mehdi; Eghlimi, Abbas; Shamanian, Morteza

2014-10-01

To study the effect of chemical composition on microstructural features and mechanical properties of dissimilar joints between super duplex and austenitic stainless steels, welding was attempted by gas tungsten arc welding process with a super duplex (ER2594) and an austenitic (ER309LMo) stainless steel filler metal. While the austenitic weld metal had vermicular delta ferrite within austenitic matrix, super duplex stainless steel was mainly comprised of allotriomorphic grain boundary and Widmanstätten side plate austenite morphologies in the ferrite matrix. Also the heat-affected zone of austenitic base metal comprised of large austenite grains with little amounts of ferrite, whereas a coarse-grained ferritic region was observed in the heat-affected zone of super duplex base metal. Although both welded joints showed acceptable mechanical properties, the hardness and impact strength of the weld metal produced using super duplex filler metal were found to be better than that obtained by austenitic filler metal.

Color-coded duplex sonography in the study of thyroid pathologic conditions

International Nuclear Information System (INIS)

Anguissola, R.; Bozzini, A.; Campani, R.; Bottinelli, O.; Genovese, E.; Guglielmoni, B.; Fulle, I.; Bandi, G.

1991-01-01

The authors examined 110 patients with suspected pathologic conditions of the thyroid by means of color-coded duplex US. In addition to the information yielded by conventional US, this technique allows organ vascularization to be demonstrated. Five normal patients were considered as a control group: no tissue vascularization was demonstrated in these cases. In 8 patients presenting with carcinoma or recurrences, vascularization was markedly increased both peripheral and central to the nodule. A few doubts are still to be solved as to the diagnostic value of color-coded duplex US in the evaluation of non-carcinomas nodular pathologic conditions. As a matter of fact, non-functioning avascular adenomas can be demonstrated only in a very low percentage of cases (66%). Color-coded duplex US proved extremely sensitive and specific in depicting malignant neoplasms. Moreover, the use of fine.needle biopsy could be optimized and subsequently reduced. Color-coded duplex US proved to be markedly superior to othe rmethods and techniques in the study of thyroid diseases, especially thyroiditis and multiple pathologic conditions. The simultaneous presence of hypocapture at scintigraphy and peripheral and central vascularization in a single nodule or within multinodular struma at color-Doppler was highly suggestive of malignant thyroid neoplasm. Color-coded duplex US is a low-cost technique, which can be performed on an outpatient basis. Moreover, it is not invasive, nor does it damage the thyroid. That is why its use is almost mandatory in the study of pathologic conditions of the thyroid

RNA-Based Stable Isotope Probing Suggests Allobaculum spp. as Particularly Active Glucose Assimilators in a Complex Murine Microbiota Cultured In Vitro

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Elena Herrmann

2017-01-01

Full Text Available RNA-based stable isotope probing (RNA-SIP and metabolic profiling were used to detect actively glucose-consuming bacteria in a complex microbial community obtained from a murine model system. A faeces-derived microbiota was incubated under anaerobic conditions for 0, 2, and 4 h with 40 mM [U13C]glucose. Isopycnic density gradient ultracentrifugation and fractionation of isolated RNA into labeled and unlabeled fractions followed by 16S rRNA sequencing showed a quick adaptation of the bacterial community in response to the added sugar, which was dominated by unclassified Lachnospiraceae species. Inspection of distinct fractions of isotope-labeled RNA revealed Allobaculum spp. as particularly active glucose utilizers in the system, as the corresponding RNA showed significantly higher proportions among the labeled RNA. With time, the labeled sugar was used by a wider spectrum of faecal bacteria. Metabolic profiling indicated rapid fermentation of [U13C]glucose, with lactate, acetate, and propionate being the principal 13C-labeled fermentation products, and suggested that “cross-feeding” occurred in the system. RNA-SIP combined with metabolic profiling of 13C-labeled products allowed insights into the microbial assimilation of a general model substrate, demonstrating the appropriateness of this technology to study assimilation processes of nutritionally more relevant substrates, for example, prebiotic carbohydrates, in the gut microbiota of mice as a model system.

Development of a panel of seven duplex real-time PCR assays for detecting 13 streptococcal superantigens.

Science.gov (United States)

Yang, Peng; Peng, Xiaomin; Cui, Shujuan; Shao, Junbin; Zhu, Xuping; Zhang, Daitao; Liang, Huijie; Wang, Quanyi

2013-07-30

Streptococcal superantigens (SAgs) are the major virulence factors of infection in humans for group A Streptococcus (GAS) bacteria. A panel consisting of seven duplex real-time PCR assays was developed to simultaneously detect 13 streptococcal SAgs and one internal control which may be important in the control of GAS-mediated diseases. Primer and probe sequences were selected based on the highly conserved region from an alignment of nucleotide sequences of the 13 streptococcal SAgs. The reaction conditions of the duplex real-time PCR were optimized and the specificity of the duplex assays was evaluated using SAg positive strains. The limit of detection of the duplex assays was determined by using 10-fold serial dilutions of the DNA of 13 streptococcal SAgs and compared to a conventional polymerase chain reaction (PCR) method for evaluating the duplex assays sensitivity. Using the duplex assays, we were able to differentiate between 13 SAgs from Streptococcus strains and other non-Streptococcus bacteria without cross-reaction. On the other hand, the limit of detection of the duplex assays was at least one or two log dilutions lower than that of the conventional PCR. The panel was highly specific (100%) and the limit of detection of these duplex groups was at least ten times lower than that obtained by using a conventional PCR method.

High affinity RNA targeting by oligonucleotides displaying aromatic stacking and amino groups in the major groove. Comparison of triazoles and phenylsubstituents

DEFF Research Database (Denmark)

Kumar, Pawan; Hornum, Mick; Nielsen, Lise Junker

2014-01-01

Three 5-modified 2'-deoxyuridine nucleosides were synthesized and incorporated into oligonucleotides and compared with the previously published 5-(1-phenyl-1,2,3-triazol-4-yl)-2'-deoxyuridine monomer W. The introduction of an aminomethyl group on the phenyl group led to monomer X, which was found...... to thermally stabilize a 9-mer DNA:RNA duplex, presumably through the partial neutralization of the negative charge of the backbone. By also taking advantage of the stacking interactions in the major groove of two or more of the monomer X, an extremely high thermal stability was obtained. A regioisomer...... monomer Z was incorporated for comparison, and it was found to give a more neutral influence on duplex stability indicating less efficient stacking interactions. The duplexes were investigated by CD spectroscopy and MD simulations....

Numerical simulation of hydrogen-assisted crack initiation in austenitic-ferritic duplex steels

International Nuclear Information System (INIS)

Mente, Tobias

2015-01-01

Duplex stainless steels have been used for a long time in the offshore industry, since they have higher strength than conventional austenitic stainless steels and they exhibit a better ductility as well as an improved corrosion resistance in harsh environments compared to ferritic stainless steels. However, despite these good properties the literature shows some failure cases of duplex stainless steels in which hydrogen plays a crucial role for the cause of the damage. Numerical simulations can give a significant contribution in clarifying the damage mechanisms. Because they help to interpret experimental results as well as help to transfer results from laboratory tests to component tests and vice versa. So far, most numerical simulations of hydrogen-assisted material damage in duplex stainless steels were performed at the macroscopic scale. However, duplex stainless steels consist of approximately equal portions of austenite and δ-ferrite. Both phases have different mechanical properties as well as hydrogen transport properties. Thus, the sensitivity for hydrogen-assisted damage is different in both phases, too. Therefore, the objective of this research was to develop a numerical model of a duplex stainless steel microstructure enabling simulation of hydrogen transport, mechanical stresses and strains as well as crack initiation and propagation in both phases. Additionally, modern X-ray diffraction experiments were used in order to evaluate the influence of hydrogen on the phase specific mechanical properties. For the numerical simulation of the hydrogen transport it was shown, that hydrogen diffusion strongly depends on the alignment of austenite and δ-ferrite in the duplex stainless steel microstructure. Also, it was proven that the hydrogen transport is mainly realized by the ferritic phase and hydrogen is trapped in the austenitic phase. The numerical analysis of phase specific mechanical stresses and strains revealed that if the duplex stainless steel is

EFFECT OF INTERMETALLIC PHASES ON CORROSION BEHAVIOR AND MECHANICAL PROPERTIES OF DUPLEX STAINLESS STEEL AND SUPER-DUPLEX STAINLESS STEEL

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Prabhu Paulraj

2015-08-01

Full Text Available Duplex Stainless Steels (DSS and Super Duplex Stainless Steel (SDSS have excellent integration of mechanical and corrosion properties. However, the formation of intermetallic phases is a major problem in their usage. The mechanical and corrosion properties are deteriorated due to the presence of intermetallic phases. These phases are induced during welding, prolonged exposure to high temperatures, and improper heat treatments. The main emphasis of this review article is on intermetallic phases and their effects on corrosion and mechanical properties. First the effect of various alloying elements on DSS and SDSS has been discussed followed by formation of various intermetallic phases. The intermetallic phases affect impact toughness and corrosion resistance significantly. Their deleterious effect on weldments has also been reviewed.

Identification of active dehalorespiring microbial populations in anoxic river sediment by RNA-based stable isotope probing

Science.gov (United States)

Kittelmann, S.; Friedrich, M. W.

2005-12-01

Tetrachloroethene (perchloroethylene, PCE), a persistent contaminant in aquifers, soils and sediments, can be reductively dechlorinated by anaerobic microorganisms in a process referred to as dehalorespiration. However, the biodiversity of dehalorespiring microorganisms and their distribution especially in pristine environments is largely unexplored. Therefore, the aim of this study was to detect potentially novel PCE-dehalorespiring microorganisms by using stable isotope probing (SIP), a technique that allows to directly identify the function of uncultivated microbial populations. We simulated a PCE contamination by incubating pristine river sediment in the presence of PCE at a steady, low aqueous concentration (20 μM). Dehalogenation activity in microcosms (20 nmol cis-dichloroethene per ml slurry per day formed) was detected already after 4 weeks at 20°C with sediment indigenous electron donors. The microbial community in sediment incubations was probed with 13C-labelled acetate (0.5 mM) as electron donor and carbon source at 15°C for 3 days. After RNA extraction, "heavy" 13C-rRNA and light 12C-rRNA were separated by isopycnic centrifugation, and Bacteria-related populations in gradient fractions were characterised by terminal restriction fragment length polymorphism analysis and cloning. In heavy gradient fractions from the microcosm with PCE, we detected a prominent 506-bp terminal restriction fragment (T-RF) and a few minor T-RFs only. In contrast, in the control without PCE, Bacteria-specific rRNA was restricted to light gradient fractions, and the prominent T-RFs found in the PCE-dechlorinating microcosm were of minor importance. Apparently, 13C-acetate was incorporated into bacterial rRNA more effectively in PCE-respiring microcosms. Thus, rRNA-SIP provides strong evidence for the presence of PCE-dehalorespiring, 13C-acetate-utilising populations in river sediment microcosms. Cloning/sequencing analysis identified the prominent members of the heavy

Mechanical properties of welded joints of duplex steels

International Nuclear Information System (INIS)

Kawiak, M.; Nowacki, J.

2003-01-01

The paper presents the study results of mechanical properties of duplex steels UNS S31803 welded joints as well as duplex and NV A36 steels welded joints. They have ben welded by FCAW method in CO 2 using FCW 2205-H flux-cored wire. The joints have been subjected: tensile tests, impact tests, bending tests, hardness tests and metallographic investigations. The influence of welding parameters and mechanical properties of the joints was appreciated. The welding method assured high tensile strength of the joints (approximately 770 MPa) and high impact strength of the welds (approximately 770 J). All samples were broken outside of welds. (author)

Preoperative Duplex Scanning is a Helpful Diagnostic Tool in Neurogenic Thoracic Outlet Syndrome.

Science.gov (United States)

Orlando, Megan S; Likes, Kendall C; Mirza, Serene; Cao, Yue; Cohen, Anne; Lum, Ying Wei; Freischlag, Julie A

2016-01-01

To evaluate the diagnostic role of venous and arterial duplex scanning in neurogenic thoracic outlet syndrome (NTOS). Retrospective review of patients who underwent duplex ultrasonography prior to first rib resection and scalenectomy (FRRS) for NTOS from 2005 to 2013. Abnormal scans included ipsilateral compression (IC) with abduction of the symptomatic extremity (>50% change in subclavian vessel flow), contralateral (asymptomatic side) compression (CC) or bilateral compression (BC). A total of 143 patients (76% female, average age 34, range 13-59) underwent bilateral preoperative duplex scanning. Ipsilateral compression was seen in 44 (31%), CC in 12 (8%), and BC in 14 (10%). Seventy-three (51%) patients demonstrated no compression. Patients with IC more often experienced intraoperative pneumothoraces (49% vs. 25%, P duplex ultrasonography can assist in NTOS diagnosis. Ipsilateral compression on abduction often correlates with Adson testing. © The Author(s) 2016.

Triple helical DNA in a duplex context and base pair opening

Science.gov (United States)

Esguerra, Mauricio; Nilsson, Lennart; Villa, Alessandra

2014-01-01

It is fundamental to explore in atomic detail the behavior of DNA triple helices as a means to understand the role they might play in vivo and to better engineer their use in genetic technologies, such as antigene therapy. To this aim we have performed atomistic simulations of a purine-rich antiparallel triple helix stretch of 10 base triplets flanked by canonical Watson–Crick double helices. At the same time we have explored the thermodynamic behavior of a flipping Watson–Crick base pair in the context of the triple and double helix. The third strand can be accommodated in a B-like duplex conformation. Upon binding, the double helix changes shape, and becomes more rigid. The triple-helical region increases its major groove width mainly by oversliding in the negative direction. The resulting conformations are somewhere between the A and B conformations with base pairs remaining almost perpendicular to the helical axis. The neighboring duplex regions maintain a B DNA conformation. Base pair opening in the duplex regions is more probable than in the triplex and binding of the Hoogsteen strand does not influence base pair breathing in the neighboring duplex region. PMID:25228466

Theoretical Characterization of Sulfur-to-Selenium Substitution in an Emissive RNA Alphabet: Impact on H-bonding Potential and Photophysical Properties

KAUST Repository

Chawla, Mohit; Poater, Albert; Besalu-Sala, Pau; Kalra, Kanav; Oliva, Romina; Cavallo, Luigi

2018-01-01

of the classical Watson-Crick base pairs, thus potentially mimicking the natural bases in a RNA duplex in terms of H-bonding. In contrast, our calculations indicate that H-bonded base pairs involving the Hoogsteen edge of purines are destabilized as compared

Interference alignment for degrees of freedom improvement in 3-relay half-duplex systems

KAUST Repository

Park, Seongho; Ko, Youngchai; Park, Kihong; Alouini, Mohamed-Slim

2011-01-01

In a half-duplex relaying, the capacity pre-log factor is a major drawback in spectral efficiency. This paper proposes a linear precoding scheme and an alternate relaying protocol in a dual-hop half-duplex system where three relays help

Value of Duplex scanning in the selection of patients for percutaneous transluminal angioplasty

NARCIS (Netherlands)

van der Heijden, F. H.; Legemate, D. A.; van Leeuwen, M. S.; Mali, W. P.; Eikelboom, B. C.

1993-01-01

Duplex scanning is becoming increasingly important in the diagnosis and follow-up of arterial lesions, though most surgeons and radiologists currently still prefer diagnostic angiography prior to percutaneous transluminal angioplasty (PTA). We performed PTA based on Duplex scanning alone in 31

Thermodynamic control of small RNA-mediated gene silencing

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Kumiko eUi-Tei

2012-06-01

Full Text Available Small interfering RNAs (siRNAs and microRNAs (miRNAs are crucial regulators of posttranscriptional gene silencing, which is referred to as RNA interference (RNAi or RNA silencing. In RNAi, siRNA loaded onto the RNA-induced silencing complex (RISC downregulates target gene expression by cleaving mRNA whose sequence is perfectly complementary to the siRNA guide strand. We previously showed that highly functional siRNAs possessed the following characteristics: A or U residues at nucleotide position 1 measured from the 5’ terminal, four to seven A/Us in positions 1–7, and G or C residues at position 19. This finding indicated that an RNA strand with a thermodynamically unstable 5’ terminal is easily retained in the RISC and functions as a guide strand. In addition, it is clear that unintended genes with complementarities only in the seed region (positions 2–8 are also downregulated by off-target effects. siRNA efficiency is mainly determined by the Watson-Crick base-pairing stability formed between the siRNA seed region and target mRNA. siRNAs with a low seed-target duplex melting temperature (Tm have little or no seed-dependent off-target activity. Thus, important parts of the RNA silencing machinery may be regulated by nucleotide base-pairing thermodynamic stability. A mechanistic understanding of thermodynamic control may enable an efficient target gene-specific RNAi for functional genomics and safe therapeutic applications.

Systematic Analysis of RNA Regulatory Network in Rat Brain after Ischemic Stroke

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Juan Liu

2018-01-01

Full Text Available Although extensive studies have identified large number of microRNAs (miRNAs and long noncoding RNAs (lncRNAs in ischemic stroke, the RNA regulation network response to focal ischemia remains poorly understood. In this study, we simultaneously interrogate the expression profiles of lncRNAs, miRNAs, and mRNAs changes during focal ischemia induced by transient middle cerebral artery occlusion. A set of 1924 novel lncRNAs were identified and may involve brain injury and DNA repair as revealed by coexpression network analysis. Furthermore, many short interspersed elements (SINE mediated lncRNA:mRNA duplexes were identified, implying that lncRNAs mediate Staufen1-mediated mRNA decay (SMD which may play a role during focal ischemia. Moreover, based on the competitive endogenous RNA (ceRNA hypothesis, a stroke regulatory ceRNA network which reveals functional lncRNA:miRNA:mRNA interactions was revealed in ischemic stroke. In brief, this work reports a large number of novel lncRNAs responding to focal ischemia and constructs a systematic RNA regulation network which highlighted the role of ncRNAs in ischemic stroke.

Oxide thickness measurement technique for duplex-layer Zircaloy-4 cladding

International Nuclear Information System (INIS)

McClelland, R.G.; O'Leary, P.M.

1992-01-01

Siemens Nuclear Power Corporation (SNP) is investigating the use of duplex-layer Zircaloy-4 tubing to improve the waterside corrosion resistance of cladding for high-burnup pressurized water reactor (PWR) fuel designs. Standard SNP PWR cladding is typically 0.762-mm (0.030-in.)-thick Zircaloy-4. The SNP duplex cladding is nominally 0.660-mm (0.026-in.)-thick Zircalloy-4 with an ∼0.102-mm (0.004-in.) outer layer of another, more corrosion-resistant, zirconium-based alloy. It is common industry practice to monitor the in-reactor corrosion behavior of Zircaloy cladding by using an eddy-current 'lift-off' technique to measure the oxide thickness on the outer surface of the fuel cladding. The test program evaluated three different cladding samples, all with the same outer diameter and wall thickness: Zircaloy-4 and duplex clad types D2 and D4

Renal duplex Doppler ultrasound findings in diabetics

International Nuclear Information System (INIS)

Shim, Hyang Yee; Kim, Young Geun; Kook, Cheol Keu; Yoon, Chong Hyun; Lee, Shin Hyung; Lee, Chang Joon

1993-01-01

The correlation between clinical-laboratory findings and renal duplex Doppler ultrasound findings was studied in 45 patients with diabetes mellitus to see the role of duplex Doppler ultrasound in the detection of diabetic nephropathy. The resistive indices in patients with elevated serum creatinine, BUN, proteinuria, and systolic blood pressure levels were statistically significantly higher than those in patients with normal levels (p<0.05). Also resistive indics in patients with retinopathy were higher than that in patients without retinopathy (p<0.05). But the ultrasound morphologic changes of kidney such as renal length, cortical eye-catching, and corticomedullarycontrast were not well correlated with clinical-laboratory data and resistive index. The resistive index of the kidney in conjunction with clinical-laboratory data in diabetics may be helpful in the evaluation of diabetic nephropathy

Renal duplex Doppler ultrasound findings in diabetics

Energy Technology Data Exchange (ETDEWEB)

Shim, Hyang Yee; Kim, Young Geun; Kook, Cheol Keu; Yoon, Chong Hyun; Lee, Shin Hyung; Lee, Chang Joon [National Medical Center, Seoul (Korea, Republic of)

1993-12-15

The correlation between clinical-laboratory findings and renal duplex Doppler ultrasound findings was studied in 45 patients with diabetes mellitus to see the role of duplex Doppler ultrasound in the detection of diabetic nephropathy. The resistive indices in patients with elevated serum creatinine, BUN, proteinuria, and systolic blood pressure levels were statistically significantly higher than those in patients with normal levels (p<0.05). Also resistive indics in patients with retinopathy were higher than that in patients without retinopathy (p<0.05). But the ultrasound morphologic changes of kidney such as renal length, cortical eye-catching, and corticomedullarycontrast were not well correlated with clinical-laboratory data and resistive index. The resistive index of the kidney in conjunction with clinical-laboratory data in diabetics may be helpful in the evaluation of diabetic nephropathy

Atomistic mechanism of microRNA translation upregulation via molecular dynamics simulations.

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Wei Ye

Full Text Available MicroRNAs are endogenous 23-25 nt RNAs that play important gene-regulatory roles in animals and plants. Recently, miR369-3 was found to upregulate translation of TNFα mRNA in quiescent (G0 mammalian cell lines. Knock down and immunofluorescence experiments suggest that microRNA-protein complexes (with FXR1 and AGO2 are necessary for the translation upregulation. However the molecular mechanism of microRNA translation activation is poorly understood. In this study we constructed the microRNA-mRNA-AGO2-FXR1 quadruple complex by bioinformatics and molecular modeling, followed with all atom molecular dynamics simulations in explicit solvent to investigate the interaction mechanisms for the complex. A combined analysis of experimental and computational data suggests that AGO2-FXR1 complex relocalize microRNA:mRNA duplex to polysomes in G0. The two strands of dsRNA are then separated upon binding of AGO2 and FXR1. Finally, polysomes may improve the translation efficiency of mRNA. The mutation research confirms the stability of microRNA-mRNA-FXR1 and illustrates importance of key residue of Ile304. This possible mechanism can shed more light on the microRNA-dependent upregulation of translation.

Assessing the effect of different operation techniques on postoperative duplex ultrasound quality after carotid endarterectomy.

Science.gov (United States)

Grambow, E; Heller, T; Wieneke, P; Weiß, C; Klar, E; Weinrich, M

2018-01-01

Duplex ultrasound is the first choice in diagnostics and surveillance of stenoses of the internal carotid arteries before and even after surgery. Therefore, the quality of duplex ultrasound is crucial to investigate these vascular pathologies. Aim of this study was the evaluation whether different surgical techniques affect the postoperative quality of duplex ultrasound. In a time period from January to May 2015 duplex ultrasound of the cervical vessels was performed in 75 patients after unilateral endarterectomy of the internal carotid artery at our department between 2006 and 2012. Thereby, the non-operated contralateral side served as a control. Study groups were defined by the surgical techniques of eversion- or thrombendarterectomy with patch plasty using different patch materials and/or a haemostatic sealant. Duplex ultrasound analysis included acoustic impedance, extinction of ultrasound, thickness of skin and individual anatomic aspects of the patients. Carotid endarterectomy itself reduced intravascular grey levels, skin thickness and increased extinction of duplex ultrasound when compared to the non-operated side of the neck. In contrast, neither the kind of chosen operative technique nor the use of different patch materials or the application of a haemostatic sealant showed an effect in this regards. Whereas carotid endarterectomy per se worsens the quality of postoperative duplex ultrasound, the different analysed surgical techniques as well as used patches and the application of a haemostatic sealant can be assumed to be equal regarding the quality of postoperative ultrasound.

Plastomes of the green algae Hydrodictyon reticulatum and Pediastrum duplex (Sphaeropleales, Chlorophyceae

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Hilary A. McManus

2017-05-01

Full Text Available Background Comparative studies of chloroplast genomes (plastomes across the Chlorophyceae are revealing dynamic patterns of size variation, gene content, and genome rearrangements. Phylogenomic analyses are improving resolution of relationships, and uncovering novel lineages as new plastomes continue to be characterized. To gain further insight into the evolution of the chlorophyte plastome and increase the number of representative plastomes for the Sphaeropleales, this study presents two fully sequenced plastomes from the green algal family Hydrodictyaceae (Sphaeropleales, Chlorophyceae, one from Hydrodictyon reticulatum and the other from Pediastrum duplex. Methods Genomic DNA from Hydrodictyon reticulatum and Pediastrum duplex was subjected to Illumina paired-end sequencing and the complete plastomes were assembled for each. Plastome size and gene content were characterized and compared with other plastomes from the Sphaeropleales. Homology searches using BLASTX were used to characterize introns and open reading frames (orfs ≥ 300 bp. A phylogenetic analysis of gene order across the Sphaeropleales was performed. Results The plastome of Hydrodictyon reticulatum is 225,641 bp and Pediastrum duplex is 232,554 bp. The plastome structure and gene order of H. reticulatum and P. duplex are more similar to each other than to other members of the Sphaeropleales. Numerous unique open reading frames are found in both plastomes and the plastome of P. duplex contains putative viral protein genes, not found in other Sphaeropleales plastomes. Gene order analyses support the monophyly of the Hydrodictyaceae and their sister relationship to the Neochloridaceae. Discussion The complete plastomes of Hydrodictyon reticulatum and Pediastrum duplex, representing the largest of the Sphaeropleales sequenced thus far, once again highlight the variability in size, architecture, gene order and content across the Chlorophyceae. Novel intron insertion sites and unique

Preparation of MS2 phage-like particles and their use as potential process control viruses for detection and quantification of enteric RNA viruses in different matrices

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Pavel Mikel

2016-12-01

Full Text Available The detection and quantification of enteric RNA viruses is based on isolation of viral RNA from the sample followed by quantitative reverse transcription polymerase chain reaction (RT-qPCR. To control the whole process of analysis and in order to guarantee the validity and reliability of results, process control viruses (PCV are used. The present article describes the process of preparation and use of such PCV– MS2 phage-like particles (MS2 PLP – in RT-qPCR detection and quantification of enteric RNA viruses. The MS2 PLP were derived from bacteriophage MS2 carrying a unique and specific de novo-constructed RNA target sequence originating from the DNA of two extinct species. The amount of prepared MS2 particles was quantified using four independent methods - UV spectrophotometry, fluorimetry, transmission electron microscopy (TEM and a specifically developed duplex RT-qPCR. To evaluate the usefulness of MS2 PLP in routine diagnostics different matrices known to harbor enteric RNA viruses (swab samples, liver tissue, serum, feces, and vegetables were artificially contaminated with specific amounts of MS2 PLP. The extraction efficiencies were calculated for each individual matrix. The prepared particles fulfill all requirements for PCV – they are very stable, non-infectious, and are genetically distinct from the target RNA viruses. Due to these properties they represent a good morphological and physiochemical model. The use of MS2 PLP as a PCV in detection and quantification of enteric RNA viruses was evaluated in different types of matrices.

Validation of a novel duplex ultrasound objective structured assessment of technical skills (DUOSATS) for arterial stenosis detection.

Science.gov (United States)

Jaffer, U; Singh, P; Pandey, V A; Aslam, M; Standfield, N J

2014-01-01

Duplex ultrasound facilitates bedside diagnosis and hence timely patient care. Its uptake has been hampered by training and accreditation issues. We have developed an assessment tool for Duplex arterial stenosis measurement for both simulator and patient based training. A novel assessment tool: duplex ultrasound assessment of technical skills was developed. A modified duplex ultrasound assessment of technical skills was used for simulator training. Novice, intermediate experience and expert users of duplex ultrasound were invited to participate. Participants viewed an instructional video and were allowed ample time to familiarize with the equipment. Participants' attempts were recorded and independently assessed by four experts using the modified duplex ultrasound assessment of technical skills. 'Global' assessment was also done on a four point Likert scale. Content, construct and concurrent validity as well as reliability were evaluated. Content and construct validity as well as reliability were demonstrated. The simulator had good satisfaction rating from participants: median 4; range 3-5. Receiver operator characteristic analysis has established a cut point of 22/ 34 and 25/ 40 were most appropriate for simulator and patient based assessment respectively. We have validated a novel assessment tool for duplex arterial stenosis detection. Further work is underway to establish transference validity of simulator training to improved skill in scanning patients. We have developed and validated duplex ultrasound assessment of technical skills for simulator training.

Four-Tap RF Canceller Evaluation for Indoor In-Band Full-Duplex Wireless Operation

Science.gov (United States)

2016-07-24

I. INTRODUCTION In-band full-duplex (IBFD) wireless operation can help alleviate the frequency spectrum congestion issues faced by current system...Valkama, “Wideband self-adaptive rf cancellation circuit for full- duplex radio: Operating principle and measurements,” in 2015 IEEE 81st Vehicular

Interactions Between Fibroblast Cells and Laser Beam Welded AISI 2205 Duplex Stainless Steel

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Ceyhun KÖSE

2018-05-01

Full Text Available Because of their high mechanical strength, excellent corrosion resistance and good weldability, duplex stainless steels are mostly used in industries such as oil, chemistry, petrochemistry, food and occasionally used in medical industry. These properties have enabled us to use duplex stainless steels in biomedical applications recently. Accordingly, duplex stainless steel material can be highly important to examine the toxic effect on the cells. In this study, the effect of the AISI 2205 duplex stainless steels which are joined by CO2 laser beam welding on viability of L929 fibroblast cells has been studied in vitro for the first time. For this aim, the cells were kept in DMEM/F-12 (Thermofisher Scientific 31331-028 medium for 7 days. The viability study was experimentally studied using the MTT (Thiazolyl Blue Tetrazolium Bromide method for 7 days. The cell viability of the laser beam welded sample has been detected to be higher than that of the base metal and the control based on 7th day data. According to the obtained results, it was revealed that laser beam welded and base metal AISI 2205 duplex stainless steel has been found suitable to study for biomedical applications. DOI: http://dx.doi.org/10.5755/j01.ms.24.2.18006

Electroless Ni-P/Ni-B duplex coatings: preparation and evaluation of microhardness, wear and corrosion resistance

International Nuclear Information System (INIS)

Narayanan, T.S.N. Sankara; Krishnaveni, K.; Seshadri, S.K.

2003-01-01

The present work deals with the formation of Ni-P/Ni-B duplex coatings by electroless plating process and evaluation of their hardness, wear resistance and corrosion resistance. The Ni-P/Ni-B duplex coatings were prepared using dual baths (acidic hypophosphite- and alkaline borohydride-reduced electroless nickel baths) with both Ni-P and Ni-B as inner layers and with varying single layer thickness. Scanning electron microscopy (SEM) was used to assess the duplex interface. The microhardness, wear resistance and corrosion resistance of electroless nickel duplex coatings were compared with electroless Ni-P and Ni-B coatings of similar thickness. The study reveals that the Ni-P and Ni-B coatings are amorphous in their as-plated condition and upon heat-treatment at 450 deg. C for 1 h, both Ni-P and Ni-B coatings crystallize and produce nickel, nickel phosphide and nickel borides in the respective coatings. All the three phases are formed when Ni-P/Ni-B and Ni-B/Ni-P duplex coatings are heat-treated at 450 deg. C for 1 h. The duplex coatings are uniform and the compatibility between the layers is good. The microhardness, wear resistance and corrosion resistance of the duplex coating is higher than Ni-P and Ni-B coatings of similar thickness. Among the two types of duplex coatings studied, hardness and wear resistance is higher for coatings having Ni-B coating as the outer layer whereas better corrosion resistance is offered by coatings having Ni-P coating as the outer layer

Effect of ultrafine grain on tensile behaviour and corrosion resistance of the duplex stainless steel.

Science.gov (United States)

Jinlong, Lv; Tongxiang, Liang; Chen, Wang; Limin, Dong

2016-05-01

The ultrafine grained 2205 duplex stainless steel was obtained by cold rolling and annealing. The tensile properties were investigated at room temperature. Comparing with coarse grained stainless steel, ultrafine grained sample showed higher strength and plasticity. In addition, grain size changed deformation orientation. The strain induced α'-martensite was observed in coarse grained 2205 duplex stainless steel with large strain. However, the grain refinement inhibited the transformation of α'-martensite;nevertheless, more deformation twins improved the strength and plasticity of ultrafine grained 2205 duplex stainless steel. In addition, the grain refinement improved corrosion resistance of the 2205 duplex stainless steel in sodium chloride solution. Copyright © 2016 Elsevier B.V. All rights reserved.

Probing binding hot spots at protein-RNA recognition sites.

Science.gov (United States)

Barik, Amita; Nithin, Chandran; Karampudi, Naga Bhushana Rao; Mukherjee, Sunandan; Bahadur, Ranjit Prasad

2016-01-29

We use evolutionary conservation derived from structure alignment of polypeptide sequences along with structural and physicochemical attributes of protein-RNA interfaces to probe the binding hot spots at protein-RNA recognition sites. We find that the degree of conservation varies across the RNA binding proteins; some evolve rapidly compared to others. Additionally, irrespective of the structural class of the complexes, residues at the RNA binding sites are evolutionary better conserved than those at the solvent exposed surfaces. For recognitions involving duplex RNA, residues interacting with the major groove are better conserved than those interacting with the minor groove. We identify multi-interface residues participating simultaneously in protein-protein and protein-RNA interfaces in complexes where more than one polypeptide is involved in RNA recognition, and show that they are better conserved compared to any other RNA binding residues. We find that the residues at water preservation site are better conserved than those at hydrated or at dehydrated sites. Finally, we develop a Random Forests model using structural and physicochemical attributes for predicting binding hot spots. The model accurately predicts 80% of the instances of experimental ΔΔG values in a particular class, and provides a stepping-stone towards the engineering of protein-RNA recognition sites with desired affinity. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

Follow-up of renal and mesenteric artery revascularization with duplex ultrasonography

Science.gov (United States)

Taylor, David C.; Houston, Gordon T.M.; Anderson, Caroline; Jameson, Margot; Popatia, Shelley

1996-01-01

Objective To evaluate the long-term anatomic results of renal revascularization procedures using duplex ultrasonography. Design A case series. Setting A university-affiliated hospital. Patients Twenty-five patients who had undergone renal percutaneous transluminal angioplasty (PTA) (18 arteries), renal bypass (10 arteries) and mesenteric bypass (6 arteries). The mean follow-up was 22 months (range from 3 to 48 months) for those who underwent renal PTA, 23 months (range from 1.5 to 70 months) for those who underwent renal bypass and 34 months (range from 8 to 144 months) for those who underwent mesenteric bypass. Main Outcome Measures Patency rates for the three procedures as assessed by duplex ultrasonography. Results Duplex ultrasonography demonstrated patency without stenosis after renal and mesenteric artery revascularization in 14 arteries subjected to renal PTA, 9 arteries subjected to renal bypass and 6 arteries subjected to mesenteric bypass. Three arteries that had renal PTA had recurrent vessel stenosis and one had occlusion. One artery that had renal bypass showed occlusion. Conclusions Renal PTA, renal bypass and mesenteric bypass are durable procedures at 2 years of follow-up, and duplex ultrasonography is a valuable method for assessing the patency of arteries after renal and mesenteric revascularization. PMID:8599785

Characterization of duplex stainless steel weld metals obtained by hybrid plasma-gas metal arc welding

OpenAIRE

Yurtisik,Koray; Tirkes,Suha; Dykhno,Igor; Gur,C. Hakan; Gurbuz,Riza

2013-01-01

Despite its high efficiency, autogenous keyhole welding is not well-accepted for duplex stainless steels because it causes excessive ferrite in as-welded duplex microstructure, which leads to a degradation in toughness and corrosion properties of the material. Combining the deep penetration characteristics of plasma arc welding in keyhole mode and metal deposition capability of gas metal arc welding, hybrid plasma - gas metal arc welding process has considered for providing a proper duplex mi...

Effects of chitosan inhibitor on the electrochemical corrosion behavior of 2205 duplex stainless steel

Science.gov (United States)

Yang, Se-fei; Wen, Ying; Yi, Pan; Xiao, Kui; Dong, Chao-fang

2017-11-01

The effects of chitosan inhibitor on the corrosion behavior of 2205 duplex stainless steel were studied by electrochemical measurements, immersion tests, and stereology microscopy. The influences of immersion time, temperature, and chitosan concentration on the corrosion inhibition performance of chitosan were investigated. The optimum parameters of water-soluble chitosan on the corrosion inhibition performance of 2205 duplex stainless steel were also determined. The water-soluble chitosan showed excellent corrosion inhibition performance on the 2205 duplex stainless steel. Polarization curves demonstrated that chitosan acted as a mixed-type inhibitor. When the stainless steel specimen was immersed in the 0.2 g/L chitosan solution for 4 h, a dense and uniform adsorption film covered the sample surface and the inhibition efficiency (IE) reached its maximum value. Moreover, temperature was found to strongly influence the corrosion inhibition of chitosan; the inhibition efficiency gradually decreased with increasing temperature. The 2205 duplex stainless steel specimen immersed in 0.4 g/L water-soluble chitosan at 30°C displayed the best corrosion inhibition among the investigated specimens. Moreover, chitosan decreased the corrosion rate of the 2205 duplex stainless steel in an FeCl3 solution.

A morphological evaluation of a duplex stainless steel processed by high energy Ball Mill

International Nuclear Information System (INIS)

Yonekubo, Ariane Emi; Cintho, Osvaldo Mitsuyuki; Aguiar, Denilson Jose Marcolino de; Capocchi, Jose Deodoro Trani

2009-01-01

The duplex stainless steels are formed by a ferrite and austenite mixture, giving them a combination of properties. Commercially, these steels are hot rolled, developing an anisotropic, alternated ferrite and austenite elongated lamellae microstructure. In this work, a duplex stainless steel was produced by the mixture of elementary powders with the composition Fe-19.5Cr-5Ni processed in an ATTRITOR ball mill during periods up to 15 hours. The powders obtained were compressed in specimens and were heat treated in the temperatures of 900, 1050 and 1200 °C during 1 hour and analysed by x ray diffraction, optic microscopy, scanning electron microscopy and energy dispersion spectroscopy. An optimized microstructure with ultrafine, equiaxial and regular duplex microstructure was obtained in the 15 hour milling and 1200 °C heat treatment. Afterwards, a commercially super duplex stainless steel UNS S32520 was aged at 800 °C aiming the precipitation of σ phase in order to reduce its toughness and then, milled in SPEX mill. The resulting microstructure was a very fine duplex type with irregular grain boundary morphology duo to the grain growth barrier promoted by the renascent σ phase particles during sintering process. (author)

Corrosion behavior of duplex and reference cladding in NPP Grohnde

International Nuclear Information System (INIS)

Besch, O.A.; Yagnik, S.K.; Eucken, C.M.; Bradley, E.R.

1996-01-01

The Nuclear Fuel Industry Research (NFIR) Group undertook a lead test assembly (LTA) program in NPP Grohnde PWR in Germany to assess the corrosion performance of duplex and reference cladding. Two identical 16 by 16 LTAs, each containing 32 peripheral test rods, completed four reactor cycles, reaching a peak rod burnup of 46 MWd/kgU. The results from poolside examinations performed at the end of each cycle, together with power histories and coolant chemistry, are reported. Five different cladding materials were characterized during fabrication. The corrosion performance of the cladding materials was tracked in long-term tests in high-pressure, high-temperature autoclaves. The relative ranking of corrosion behavior in such tests corresponded well with the in-reactor corrosion performance. The extent and distribution of hydriding in duplex and reference specimens during the autoclave testing has been characterized. The in-reactor corrosion data indicate that the low-tin Zircaloy-4 reference cladding, R2, had an improved corrosion resistance compared to high-tin Zircaloy-4 reference cladding, R1. Two types of duplex cladding, D1 (Zr-2.5% Nb) and D2 (Zr-0.4% Fe-0.5% Sn), showed an even further improvement in corrosion resistance compared to R2 cladding. The third duplex cladding, D3 (Zr-4 + 1.0% Nb), had significantly less corrosion resistance, which was inferior to R1. The in-reactor and out-reactor corrosion performances have been ranked

Approximation methods for the stability analysis of complete synchronization on duplex networks

Science.gov (United States)

Han, Wenchen; Yang, Junzhong

2018-01-01

Recently, the synchronization on multi-layer networks has drawn a lot of attention. In this work, we study the stability of the complete synchronization on duplex networks. We investigate effects of coupling function on the complete synchronization on duplex networks. We propose two approximation methods to deal with the stability of the complete synchronization on duplex networks. In the first method, we introduce a modified master stability function and, in the second method, we only take into consideration the contributions of a few most unstable transverse modes to the stability of the complete synchronization. We find that both methods work well for predicting the stability of the complete synchronization for small networks. For large networks, the second method still works pretty well.

DNA-, RNA-, and Protein-Based Stable-Isotope Probing for High-Throughput Biomarker Analysis of Active Microorganisms.

Science.gov (United States)

Jameson, Eleanor; Taubert, Martin; Coyotzi, Sara; Chen, Yin; Eyice, Özge; Schäfer, Hendrik; Murrell, J Colin; Neufeld, Josh D; Dumont, Marc G

2017-01-01

Stable-isotope probing (SIP) enables researchers to target active populations within complex microbial communities, which is achieved by providing growth substrates enriched in heavy isotopes, usually in the form of 13 C, 18 O, or 15 N. After growth on the substrate and subsequent extraction of microbial biomarkers, typically nucleic acids or proteins, the SIP technique is used for the recovery and analysis of isotope-labeled biomarkers from active microbial populations. In the years following the initial development of DNA- and RNA-based SIP, it was common practice to characterize labeled populations by targeted gene analysis. Such approaches usually involved fingerprint-based analyses or sequencing of clone libraries containing 16S rRNA genes or functional marker gene amplicons. Although molecular fingerprinting remains a valuable approach for rapid confirmation of isotope labeling, recent advances in sequencing technology mean that it is possible to obtain affordable and comprehensive amplicon profiles, metagenomes, or metatranscriptomes from SIP experiments. Not only can the abundance of microbial groups be inferred from metagenomes, but researchers can bin, assemble, and explore individual genomes to build hypotheses about the metabolic capabilities of labeled microorganisms. Analysis of labeled mRNA is a more recent advance that can provide independent metatranscriptome-based analysis of active microorganisms. The power of metatranscriptomics is that mRNA abundance often correlates closely with the corresponding activity of encoded enzymes, thus providing insight into microbial metabolism at the time of sampling. Together, these advances have improved the sensitivity of SIP methods and allow the use of labeled substrates at ecologically relevant concentrations. Particularly as methods improve and costs continue to drop, we expect that the integration of SIP with multiple omics-based methods will become prevalent components of microbial ecology studies

Standard test methods for characterizing duplex grain sizes

CERN Document Server

American Society for Testing and Materials. Philadelphia

2002-01-01

1.1 These test methods provide simple guidelines for deciding whether a duplex grain size exists. The test methods separate duplex grain sizes into one of two distinct classes, then into specific types within those classes, and provide systems for grain size characterization of each type. 1.2 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns associated with its use. It is the responsibility of the user of this standard to consult appropriate safety and health practices and determine the applicability of regulatory limitations prior to its use.

Brownian dynamics simulations of sequence-dependent duplex denaturation in dynamically superhelical DNA

Science.gov (United States)

Mielke, Steven P.; Grønbech-Jensen, Niels; Krishnan, V. V.; Fink, William H.; Benham, Craig J.

2005-09-01

The topological state of DNA in vivo is dynamically regulated by a number of processes that involve interactions with bound proteins. In one such process, the tracking of RNA polymerase along the double helix during transcription, restriction of rotational motion of the polymerase and associated structures, generates waves of overtwist downstream and undertwist upstream from the site of transcription. The resulting superhelical stress is often sufficient to drive double-stranded DNA into a denatured state at locations such as promoters and origins of replication, where sequence-specific duplex opening is a prerequisite for biological function. In this way, transcription and other events that actively supercoil the DNA provide a mechanism for dynamically coupling genetic activity with regulatory and other cellular processes. Although computer modeling has provided insight into the equilibrium dynamics of DNA supercoiling, to date no model has appeared for simulating sequence-dependent DNA strand separation under the nonequilibrium conditions imposed by the dynamic introduction of torsional stress. Here, we introduce such a model and present results from an initial set of computer simulations in which the sequences of dynamically superhelical, 147 base pair DNA circles were systematically altered in order to probe the accuracy with which the model can predict location, extent, and time of stress-induced duplex denaturation. The results agree both with well-tested statistical mechanical calculations and with available experimental information. Additionally, we find that sites susceptible to denaturation show a propensity for localizing to supercoil apices, suggesting that base sequence determines locations of strand separation not only through the energetics of interstrand interactions, but also by influencing the geometry of supercoiling.

Novel RNA Duplex Locks HIV-1 in a Latent State via Chromatin-mediated Transcriptional Silencing

Directory of Open Access Journals (Sweden)

Chantelle Ahlenstiel

2015-01-01

Full Text Available Transcriptional gene silencing (TGS of mammalian genes can be induced by short interfering RNA (siRNA targeting promoter regions. We previously reported potent TGS of HIV-1 by siRNA (PromA, which targets tandem NF-κB motifs within the viral 5′LTR. In this study, we screened a siRNA panel with the aim of identifying novel 5′LTR targets, to provide multiplexing potential with enhanced viral silencing and application toward developing alternate therapeutic strategies. Systematic examination identified a novel siRNA target, si143, confirmed to induce TGS as the silencing mechanism. TGS was prolonged with virus suppression >12 days, despite a limited ability to induce post- TGS. Epigenetic changes associated with silencing were suggested by partial reversal by histone deacetylase inhibitors and confirmed by chromatin immunoprecipitation analyses, which showed induction of H3K27me3 and H3K9me3, reduction in H3K9Ac, and recruitment of argonaute-1, all characteristic marks of heterochromatin and TGS. Together, these epigenetic changes mimic those associated with HIV-1 latency. Further, robust resistance to reactivation was observed in the J-Lat 9.2 cell latency model, when transduced with shPromA and/or sh143. These data support si/shRNA-mediated TGS approaches to HIV-1 and provide alternate targets to pursue a functional cure, whereby the viral reservoir is locked in latency following antiretroviral therapy cessation.

Problems in repair-welding of duplex-treated tool steels

Directory of Open Access Journals (Sweden)

T. Muhič

2009-01-01

Full Text Available The present paper addresses problems in laser welding of die-cast tools used for aluminum pressure die-castings and plastic moulds. To extend life cycle of tools various surface improvements are used. These surface improvements significantly reduce weldability of the material. This paper presents development of defects in repair welding of duplex-treated tool steel. The procedure is aimed at reduction of defects by the newly developed repair laser welding techniques. Effects of different repair welding process parameters and techniques are considered. A microstructural analysis is conducted to detect defect formation and reveal the best laser welding method for duplex-treated tools.

NMR studies of abasic sites in DNA duplexes: Deoxyadenosine stacks into the helix opposite acyclic lesions

International Nuclear Information System (INIS)

Kalnik, M.W.; Chang, Chienneng; Johnson, F.; Grollman, A.P.; Patel, D.J.

1989-01-01

Proton and phosphorus NMR studies are reported for two complementary nonanucleotide duplexes containing acyclic abasic sites. The first duplex, d(C-A-T-G-A-G-T-A-C)·d(G-T-A-C-P-C-A-T-G), contains an acyclic propanyl moiety, P, located opposite a deoxyadenosine at the center of the helix (designated AP P 9-mer duplex). The second duplex, d(C-A-T-G-A-G-T-A-C-)·d(G-T-A-C-E-C-A-T-G), contains a similarly located acyclic ethanyl moiety, E (designated AP E 9-mer duplex). The ethanyl moiety is one carbon shorter than the natural carbon-phosphodiester backbone of a single nucleotide unit of DNA. The majority of the exchangeable and nonexchangeable base and sugar protons in both the AP P 9-mer and AP E 9-mer duplexes, including those at the abasic site, have been assigned by recording and analyzing two-dimensional phase-sensitive NOESY data sets in H 2 O and D 2 O solution between -5 and 5 degree C. These spectroscopic observations establish that A5 inserts into the helix opposite the abasic site (P14 and El14) and stacks between the flanking G4·C15 and G6·C13 Watson-Crick base pairs in both the AP P 9-mer and AP E 9-mer duplexes. Proton NMR parameters for the Ap P 9-mer and AP E 9-mer duplexes are similar to those reported previously. These proton NMR experiments demonstrate that the structures at abasic sites are very similar whether the five-membered ring is open or closed or whether the phosphodiester backbone is shortened by one carbon atom. Phosphorus spectra of the AP P 9-mer and AP E 9-mer duplexes (5 degree C) indicate that the backbone conformation is similarly perturbed at three phosphodiester backbone torsion angles

Surgical retroperitoneoscopic and transperitoneoscopic access in varicocelectomy: duplex scan results in pediatric population.

Science.gov (United States)

Mancini, Stefano; Bulotta, Anna Lavinia; Molinaro, Francesco; Ferrara, Francesco; Tommasino, Giulio; Messina, Mario

2014-12-01

This is a retrospective study to compare duplex scan results of laparoscopic Palomo's technique through retroperitoneal and transperitoneal approach for varicocelectomy in children. We statistically analyzed recurrence, testicular volume growth and complications. Surgical intervention was performed utilizing transperitoneoscopic (group A) or retroperitoneoscopic access (group B). Duplex scan control was performed after 12 months (T1), after 2 years (T2) and the last one at 18 years old in most patients. Statistical analysis was performed using the t-test for parametric data. Differences in proportions were evaluated using χ2 or Fisher's exact test. We treated 120 children (age range 10-17 years) who presented an asymptomatic IV grade of reflux, Coolsaet 1, associated with a left testicular hypotrophy in 36.6% of the cases (44 patients). No post-operative complications were verified. Duplex scan exam showed an increase of left testicular growth in both groups, with complete hypotrophy disappear in patients in both groups after 24 months. Hydrocele, diagnosed clinically and confirmed with duplex scan, was the most frequent post-operative complication (22/120 cases; 18.3%). This study showed the importance of duplex scan at all steps of this vascular pathology in children, and that there is no significantly difference in results between the two surgical techniques except for hydrocele in transperitoneoscopic access. Copyright © 2014 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

Duplex ultrasound for identifying renal artery stenosis

DEFF Research Database (Denmark)

Zachrisson, Karin; Herlitz, Hans; Lönn, Lars

2017-01-01

Background Renal artery duplex ultrasound (RADUS) is an established method for diagnosis of renal artery stenosis (RAS), but there is no consensus regarding optimal RADUS criteria. Purpose To define optimal cutoff values for RADUS parameters when screening for RAS using intra-arterial trans...

Duplex Design Project: Science Pilot Test.

Science.gov (United States)

Center for Research on Evaluation, Standards, and Student Testing, Los Angeles, CA.

Work is reported towards the completion of a prototype duplex-design assessment instrument for grade-12 science. The student course-background questionnaire and the pretest section of the two-stage instrument that was developed were administered to all 134 12th-grade students at St. Clairsville High School (Ohio). Based on the information obtained…

Electrolytic pickling of duplex stainless steel

Energy Technology Data Exchange (ETDEWEB)

Ipek, N.; Holm, B.; Pettersson, R. [Swedish Institute for Metals Research, Drottning Kristinas vaeg 48, 11428 Stockholm (Sweden); Runnsjoe, G.; Karlsson, M. [Outokumpu Stainless AB, 77422 Avesta (Sweden)

2005-08-01

Pickling of duplex stainless steels has proved to be much more difficult than that of standard austenitic grades. Electrolytic pre-pickling is shown to be a key process towards facilitating the pickling process for material annealed both in the production-line and in laboratory experiments. The mechanism for the neutral electrolytic process on duplex 2205 and austenitic 316 steels has been examined and the oxide scale found to become thinner as a function of electrolytic pickling time. Spallation or peeling of the oxide induced by gas evolution did not play a decisive role. A maximum of about 20% of the current supplied to the oxidised steel surface goes to dissolution reactions whereas about 80% of the current was consumed in oxygen gas production. This makes the current utilisation very poor, particularly against the background of reports that in indirect electrolytic pickling only about 30% of the total current, supplied to the process, actually goes into the strip. A parametric study was therefore carried out to determine whether adjustment of process variables could improve the current utilisation. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

Molecular architecture: construction of self-assembled organophosphonate duplexes and their electrochemical characterization.

Science.gov (United States)

Cattani-Scholz, Anna; Liao, Kung-Ching; Bora, Achyut; Pathak, Anshuma; Hundschell, Christian; Nickel, Bert; Schwartz, Jeffrey; Abstreiter, Gerhard; Tornow, Marc

2012-05-22

Self-assembled monolayers of phosphonates (SAMPs) of 11-hydroxyundecylphosphonic acid, 2,6-diphosphonoanthracene, 9,10-diphenyl-2,6-diphosphonoanthracene, and 10,10'-diphosphono-9,9'-bianthracene and a novel self-assembled organophosphonate duplex ensemble were synthesized on nanometer-thick SiO(2)-coated, highly doped silicon electrodes. The duplex ensemble was synthesized by first treating the SAMP prepared from an aromatic diphosphonic acid to form a titanium complex-terminated one; this was followed by addition of a second equivalent of the aromatic diphosphonic acid. SAMP homogeneity, roughness, and thickness were evaluated by AFM; SAMP film thickness and the structural contributions of each unit in the duplex were measured by X-ray reflection (XRR). The duplex was compared with the aliphatic and aromatic monolayer SAMPs to determine the effect of stacking on electrochemical properties; these were measured by impedance spectroscopy using aqueous electrolytes in the frequency range 20 Hz to 100 kHz, and data were analyzed using resistance-capacitance network based equivalent circuits. For the 11-hydroxyundecylphosphonate SAMP, C(SAMP) = 2.6 ± 0.2 μF/cm(2), consistent with its measured layer thickness (ca. 1.1 nm). For the anthracene-based SAMPs, C(SAMP) = 6-10 μF/cm(2), which is attributed primarily to a higher effective dielectric constant for the aromatic moieties (ε = 5-10) compared to the aliphatic one; impedance spectroscopy measured the additional capacitance of the second aromatic monolayer in the duplex (2ndSAMP) to be C(Ti/2ndSAMP) = 6.8 ± 0.7 μF/cm(2), in series with the first.

A conserved small RNA promotes silencing of the outer membrane protein YbfM

DEFF Research Database (Denmark)

Rasmussen, Anders Aamann; Johansen, Jesper; Nielsen, Jesper S

2009-01-01

important physiological role of regulatory RNA molecules in Gram-negative bacteria is to modulate the cell surface and/or to prevent accumulation of OMPs in the envelope. Here, we extend the OMP-sRNA network by showing that the expression of the outer membrane protein YbfM is silenced by a conserved sRNA......In the past few years an increasing number of small non-coding RNAs (sRNAs) in enterobacteria have been found to negatively regulate the expression of outer membrane proteins (OMPs) at the post-transcriptional level. These RNAs act under various growth and stress conditions, suggesting that one......, designated MicM (also known as RybC/SroB). The regulation is strictly dependent on the RNA chaperone Hfq, and mutational analysis indicates that MicM sequesters the ribosome binding site of ybfM mRNA by an antisense mechanism. Furthermore, we provide evidence that Hfq strongly enhances the on-rate of duplex...

Duplex Schemes in Multiple Antenna Two-Hop Relaying

Directory of Open Access Journals (Sweden)

Anja Klein

2008-04-01

Full Text Available A novel scheme for two-hop relaying defined as space division duplex (SDD relaying is proposed. In SDD relaying, multiple antenna beamforming techniques are applied at the intermediate relay station (RS in order to separate downlink and uplink signals of a bi-directional two-hop communication between two nodes, namely, S1 and S2. For conventional amplify-and-forward two-hop relaying, there appears a loss in spectral efficiency due to the fact that the RS cannot receive and transmit simultaneously on the same channel resource. In SDD relaying, this loss in spectral efficiency is circumvented by giving up the strict separation of downlink and uplink signals by either time division duplex or frequency division duplex. Two novel concepts for the derivation of the linear beamforming filters at the RS are proposed; they can be designed either by a three-step or a one-step concept. In SDD relaying, receive signals at S1 are interfered by transmit signals of S1, and receive signals at S2 are interfered by transmit signals of S2. An efficient method in order to combat this kind of interference is proposed in this paper. Furthermore, it is shown how the overall spectral efficiency of SDD relaying can be improved if the channels from S1 and S2 to the RS have different qualities.

Internal Carotid Artery Hypoplasia: Role of Color-Coded Carotid Duplex Sonography.

Science.gov (United States)

Chen, Pei-Ya; Liu, Hung-Yu; Lim, Kun-Eng; Lin, Shinn-Kuang

2015-10-01

The purpose of this study was to determine the role of color-coded carotid duplex sonography for diagnosis of internal carotid artery hypoplasia. We retrospectively reviewed 25,000 color-coded carotid duplex sonograms in our neurosonographic database to establish more diagnostic criteria for internal carotid artery hypoplasia. A definitive diagnosis of internal carotid artery hypoplasia was made in 9 patients. Diagnostic findings on color-coded carotid duplex imaging include a long segmental small-caliber lumen (52% diameter) with markedly decreased flow (13% flow volume) in the affected internal carotid artery relative to the contralateral side but without intraluminal lesions. Indirect findings included markedly increased total flow volume (an increase of 133%) in both vertebral arteries, antegrade ipsilateral ophthalmic arterial flow, and a reduced vessel diameter with increased flow resistance in the ipsilateral common carotid artery. Ten patients with distal internal carotid artery dissection showed a similar color-coded duplex pattern, but the reductions in the internal and common carotid artery diameters and increase in collateral flow from the vertebral artery were less prominent than those in hypoplasia. The ipsilateral ophthalmic arterial flow was retrograde in 40% of patients with distal internal carotid artery dissection. In addition, thin-section axial and sagittal computed tomograms of the skull base could show the small diameter of the carotid canal in internal carotid artery hypoplasia and help distinguish hypoplasia from distal internal carotid artery dissection. Color-coded carotid duplex sonography provides important clues for establishing a diagnosis of internal carotid artery hypoplasia. A hypoplastic carotid canal can be shown by thin-section axial and sagittal skull base computed tomography to confirm the final diagnosis. © 2015 by the American Institute of Ultrasound in Medicine.

Development and properties of duplex MgF2/PCL coatings on biodegradable magnesium alloy for biomedical applications.

Science.gov (United States)

Makkar, Preeti; Kang, Hoe Jin; Padalhin, Andrew R; Park, Ihho; Moon, Byoung-Gi; Lee, Byong Taek

2018-01-01

The present work addresses the performance of polycaprolactone (PCL) coating on fluoride treated (MgF2) biodegradable ZK60 magnesium alloy (Mg) for biomedical application. MgF2 conversion layer was first produced by immersing Mg alloy substrate in hydrofluoric acid solution. The outer PCL coating was then prepared using dip coating technique. Morphology, elements profile, phase structure, roughness, mechanical properties, invitro corrosion, and biocompatibility of duplex MgF2/PCL coating were then characterized and compared to those of fluoride coated and uncoated Mg samples. The invivo degradation behavior and biocompatibility of duplex MgF2/PCL coating with respect to ZK60 Mg alloy were also studied using rabbit model for 2 weeks. SEM and TEM analysis showed that the duplex coating was uniform and comprised of porous PCL film (~3.3 μm) as upper layer with compact MgF2 (~2.2 μm) as inner layer. No significant change in microhardness was found on duplex coating compared with uncoated ZK60 Mg alloy. The duplex coating showed improved invitro corrosion resistance than single layered MgF2 or uncoated alloy samples. The duplex coating also resulted in better cell viability, cell adhesion, and cell proliferation compared to fluoride coated or uncoated alloy. Preliminary invivo studies indicated that duplex MgF2/PCL coating reduced the degradation rate of ZK60 Mg alloy and exhibited good biocompatibility. These results suggested that duplex MgF2/PCL coating on magnesium alloy might have great potential for orthopedic applications.

Potential of duplex fuel in prebreeder, breeder, and power reactor designs: tests and analyses (AWBA Development Program)

International Nuclear Information System (INIS)

Chao, T.L.; Brennan, J.J.; Duncombe, E.; Schneider, M.J.; Johnson, R.G.R.

1982-09-01

Dual region fuel pellets, called duplex pellets, are comprised of an outer annular region of relatively high uranium fuel enrichment and a center pellet of fertile material with no enrichment. UO 2 and ThO 2 are the fissile and fertile materials of interest. Both prebreeders and breeders are discussed as are the performance advantages of duplex pellets over solid pellets in these two pressurized water reactor types. Advantages of duplex pellets for commercial reactor fuel rods are also discussed. Both irradiation test data and analytical results are used in comparisons. Manufacturing of duplex fuel is discussed

Can duplex Doppler ultrasound replace computerized tomography in staging patients with renal cell carcinoma?

NARCIS (Netherlands)

Bos, SD; Mensink, HJA

The purpose of this study was to evaluate the accuracy and reliability of duplex Doppler ultrasound (US) and computerized tomography (CT) in staging patients with renal cell carcinoma (RCC). Sixty-six patients were evaluated pre-operatively with duplex Doppler ultrasound and CT. The results were

Duplex System with Ectopic Ureter Opens into the Posterior Urethra: Case Report.

Science.gov (United States)

Milicevic, Snjezana; Bijelic, Radojka; Krivokuca, Vladimir; Jakovljevic, Branislava

2018-04-01

Duplicated ureter or Duplex Collecting System is a congenital condition in which the ureteric bud, the embryological origin of the ureter, arises twice, resulting in two ureters draining a single kidney. This congenital anomaly is rare, and even rarer when the duplex system with ectopic ureter is present. This type of congenital anomaly is even more rarely diagnosed and surgically treated in adulthood. This case report presents a case of a 32-year-old male, who had a duplex collecting system with two ureters on the left side. Ectopic ureter, draining the upper pole of the left kidney, opened into the posterior urethra. In our patient, taking into account the clinical perspective, the renal tissue damaging of the upper pole which was not functional, partial nephrectomy and ureterectomy was successfully performed.

Duplex investigations in children: Are clinical signs in children with venous disorders relevant?

Science.gov (United States)

Birgitte Maessen-Visch, M; Smeets, L; van Vleuten, C

2015-12-01

Ultra sound colored duplex sonography is the preferred method in diagnosing chronic venous disease. Data in children on incidence, indications, and results are lacking. From the total of 9180 duplex investigations performed in our hospital from 2009 to 2012, data on indication and results of the investigation as well as patient characteristics were evaluated retrospectively for the proportion of pediatric patients. Duplex investigations were performed 49 times in 38 children (6-18 years), with an average of 1.3 times (1-6 times) per child. Forty percent showed abnormalities: 17 times deep venous thrombosis was suspected; deep venous thrombosis was objectified in 18%. In the 21 investigations performed for varicosis-related complaints, varicose veins or venous malformations were objectified in 57%. Edema was never a symptom of chronic venous disease. Duplex investigation is not often performed in children. In children with established deep venous thrombosis, a family history with deep venous thrombosis is common. In general, edema was not seen in children with varicose veins and, therefore, does not seem a reliable clinical sign at young age. © The Author(s) 2014.

An oligonucleotide complementary to the SL-B1 domain in the 3'-end of the minus-strand RNA of the hepatitis C virus inhibits in vitro initiation of RNA synthesis by the viral polymerase

International Nuclear Information System (INIS)

Reigadas, Sandrine; Ventura, Michel; Andreola, Marie-Line; Michel, Justine; Gryaznov, Sergei; Tarrago-Litvak, Laura; Litvak, Simon; Astier-Gin, Therese

2003-01-01

We describe oligonucleotides (ODNs) that inhibit hepatitis C virus (HCV) RNA synthesis in vitro. From a series of 13 ODNs complementary to the 3'-end of the minus-strand HCV RNA, only 4 inhibited RNA synthesis with IC 50 values lower than 1 μM. The inhibition was sequence-specific, since no effect was observed when the ODNs were used with a noncomplementary template. The introduction of a 2'-O-methyl modification increased the inhibitor activity 11-fold (IC 50 = 50 nM) in just 1 (ODN7) of the 4 inhibitory ODNs. ODNs did not inhibit RNA synthesis by interfering with the elongation process as no short RNAs products were detected. We also show that ODN7 did not prevent binding of NS5B to the template or cause polymerase trapping by the duplex RNA/ODN. Our data demonstrate that ODN7 inhibits the initiation process, most probably by modifying structural features present at the 3'-end of the minus-strand RNA

Electroporation and microinjection successfully deliver single-stranded and duplex DNA into live cells as detected by FRET measurements.

Directory of Open Access Journals (Sweden)

Rosemary A Bamford

Full Text Available Förster resonance energy transfer (FRET technology relies on the close proximity of two compatible fluorophores for energy transfer. Tagged (Cy3 and Cy5 complementary DNA strands forming a stable duplex and a doubly-tagged single strand were shown to demonstrate FRET outside of a cellular environment. FRET was also observed after transfecting these DNA strands into fixed and live cells using methods such as microinjection and electroporation, but not when using lipid based transfection reagents, unless in the presence of the endosomal acidification inhibitor bafilomycin. Avoiding the endocytosis pathway is essential for efficient delivery of intact DNA probes into cells.

Development of duplex RT-PCR-ELISA for the simultaneous detection of hepatitis A virus and hepatitis E virus.

Science.gov (United States)

Tahk, Hongmin; Lee, Min Hwa; Lee, Kang Bum; Cheon, Doo-Sung; Choi, Changsun

2011-07-01

This study aimed to develop a specific and sensitive duplex reverse transcription polymerase chain reaction enzyme-linked immunosorbent assay (duplex RT-PCR-ELISA) for hepatitis A virus (HAV) and hepatitis E virus (HEV). Duplex RT-PCR-ELISA could detect and differentiate HAV and HEV with specific probes. When ELISA technique was used to detect probe-bound RT-PCR products, duplex RT-PCR-ELISA could detect as little as 0.1 ng/μL HAV and HEV from clinical samples. Human norovirus, enterovirus, poliovirus, murine norovirus and feline calicivirus were used for the specificity test; all were negative. Therefore duplex RT-PCR-ELISA can be used for the simultaneous detection of HAV and HEV in contaminated fecal samples. Copyright © 2011 Elsevier B.V. All rights reserved.

Fatigue crack propagation behavior and acoustic emission characteristics of the heat affected zone of super duplex stainless steel

International Nuclear Information System (INIS)

Do, Jae Yoon; Kim, Jin Hwan; Ahn, Seok Hwan; Park, In Duck; Kang, Chang Yong; Nam, Ki Woo

2002-01-01

Because duplex stainless steel shows the good strength and corrosion resistance properties, the necessity of duplex stainless steel, which has long life in severe environments, has been increased with industrial development. The fatigue crack propagation behavior of Heat Affected Zone(HAZ) has been investigated in super duplex stainless steel. The fatigue crack propagation rate of HAZ of super duplex stainless steel was faster than that of base metal of super duplex stainless steel. We also analysed acoustic emission signals during the fatigue test with time-frequency analysis method. According to the results of time-frequency analysis, the frequency ranges of 200-400 kHz were obtained by striation and the frequency range of 500 kHz was obtained due to dimple and separate of inclusion

Weld oxide formation on lean duplex stainless steel

Energy Technology Data Exchange (ETDEWEB)

Westin, E.M. [Outokumpu Stainless, Avesta Research Centre, P.O. Box 74, SE-774 22 Avesta (Sweden)], E-mail: elin.westin@outokumpu.com; Olsson, C.-O.A. [Outokumpu Stainless, Avesta Research Centre, P.O. Box 74, SE-774 22 Avesta (Sweden); Hertzman, S. [Outokumpu Stainless Research Foundation, Brinellvaegen 23, SE-100 44 Stockholm (Sweden)

2008-09-15

Weld oxides have a strong influence on corrosion resistance, but have hitherto only been studied to a limited extent for duplex stainless steels. X-ray photoelectron spectroscopy (XPS) has here been used to study heat tint formed on gas tungsten arc (GTA) welds on the commercial duplex grades LDX 2101 (EN 1.4162/UNS S32101) and 2304 (EN 1.4362/UNS S32304) welded with and without nitrogen additions to the shielding gas. The process of heat tint formation is discussed in terms of transport phenomena to explain the effect of atmosphere, temperature and composition. The oxides formed were found to be enriched in manganese and corrosion testing shows that nitrogen has a strong influence on the weld oxide. A mechanism is proposed including evaporation from the weld pool and subsequent redeposition.

Weld oxide formation on lean duplex stainless steel

International Nuclear Information System (INIS)

Westin, E.M.; Olsson, C.-O.A.; Hertzman, S.

2008-01-01

Weld oxides have a strong influence on corrosion resistance, but have hitherto only been studied to a limited extent for duplex stainless steels. X-ray photoelectron spectroscopy (XPS) has here been used to study heat tint formed on gas tungsten arc (GTA) welds on the commercial duplex grades LDX 2101 (EN 1.4162/UNS S32101) and 2304 (EN 1.4362/UNS S32304) welded with and without nitrogen additions to the shielding gas. The process of heat tint formation is discussed in terms of transport phenomena to explain the effect of atmosphere, temperature and composition. The oxides formed were found to be enriched in manganese and corrosion testing shows that nitrogen has a strong influence on the weld oxide. A mechanism is proposed including evaporation from the weld pool and subsequent redeposition

Evolution of specific 3'-5'-linkages in RNA in pre-biotic soup: a new hypothesis.

Science.gov (United States)

Kumar, Vaijayanti A

2016-11-02

This article reviews the different possibilities towards progression of the formation of DNA/RNA in the chemical world, before life, in enzyme-free conditions. The advent of deoxyribo- and ribopentose-sugars, nucleosides, nucleotides and oligonucleotides in the prebiotic soup is briefly discussed. Further, the formation of early single stranded oligomers, base-pairing possibilities and information transfer based on the stability parameters of the derived duplexes is reviewed. Each theory has its own merits and demerits which we have elaborated upon. Lastly, using clues from this literature, a possible explanation for the specific 3'-5'-linkages in RNA is proposed.

Investigation of hot cracking resistance of 2205 duplex steel

Energy Technology Data Exchange (ETDEWEB)

Adamiec, J; Scibisz, B, E-mail: janusz.adamiec@polsl.pl [Silesian University of Technology, Faculty of Materials Science and Metallurgy, ul. Krasinskiego 8, PL-40019 Katowice (Poland)

2010-02-15

Austenitic duplex steel of the brand 2205 according to Avesta Sheffield is used for welded constructions (pipelines, tanks) in the petrol industry, chemical industry and food industry. It is important to know the range of high-temperature brittleness in designing welding technology for constructions made of this steel type. There is no data in literature concerning this issue. High-temperature brittleness tests using the simulator of heat flow device Gleeble 3800 were performed. The tests results allowed the evaluation of the characteristic temperatures in the brittleness temperature range during the joining of duplex steels, specifically the nil-strength temperature (NST) and nil-ductility temperatures (NDT) during heating, the strength and ductility recovery temperatures (DRT) during cooling, the R{sub f}parameter (R{sub f} = (T{sub liquidus} - NDT)/NDT) describing the duplex steel inclination for hot cracking, and the brittleness temperature range (BTR). It has been stated that, for the examined steel, this range is wide and amounts to ca. 90 deg. C. The joining of duplex steels with the help of welding techniques creates a significant risk of hot cracks. After analysis of the DTA curves a liquidus temperature of T{sub L} = 1465 deg. C and a solidus temperature of T{sub S} = 1454 deg. C were observed. For NST a mean value was assumed, in which the cracks appeared for six samples; the temperature was 1381 deg. C. As the value of the NDT temperature 1367 deg. C was applied while for DRT the assumed temperature was 1375 deg. C. The microstructure of the fractures was observed using a Hitachi S-3400N scanning electron microscope (SEM). The analyses of the chemical composition were performed using an energy-dispersive X-ray spectrometer (EDS), Noran System Six of Thermo Fisher Scientific. Essential differences of fracture morphology type over the brittle temperature range were observed and described.

Investigation of hot cracking resistance of 2205 duplex steel

Science.gov (United States)

Adamiec, J.; Ścibisz, B.

2010-02-01

Austenitic duplex steel of the brand 2205 according to Avesta Sheffield is used for welded constructions (pipelines, tanks) in the petrol industry, chemical industry and food industry. It is important to know the range of high-temperature brittleness in designing welding technology for constructions made of this steel type. There is no data in literature concerning this issue. High-temperature brittleness tests using the simulator of heat flow device Gleeble 3800 were performed. The tests results allowed the evaluation of the characteristic temperatures in the brittleness temperature range during the joining of duplex steels, specifically the nil-strength temperature (NST) and nil-ductility temperatures (NDT) during heating, the strength and ductility recovery temperatures (DRT) during cooling, the Rfparameter (Rf = (Tliquidus - NDT)/NDT) describing the duplex steel inclination for hot cracking, and the brittleness temperature range (BTR). It has been stated that, for the examined steel, this range is wide and amounts to ca. 90 °C. The joining of duplex steels with the help of welding techniques creates a significant risk of hot cracks. After analysis of the DTA curves a liquidus temperature of TL = 1465 °C and a solidus temperature of TS = 1454 °C were observed. For NST a mean value was assumed, in which the cracks appeared for six samples; the temperature was 1381 °C. As the value of the NDT temperature 1367 °C was applied while for DRT the assumed temperature was 1375 °C. The microstructure of the fractures was observed using a Hitachi S-3400N scanning electron microscope (SEM). The analyses of the chemical composition were performed using an energy-dispersive X-ray spectrometer (EDS), Noran System Six of Thermo Fisher Scientific. Essential differences of fracture morphology type over the brittle temperature range were observed and described.

Investigation of hot cracking resistance of 2205 duplex steel

International Nuclear Information System (INIS)

Adamiec, J; Scibisz, B

2010-01-01

Austenitic duplex steel of the brand 2205 according to Avesta Sheffield is used for welded constructions (pipelines, tanks) in the petrol industry, chemical industry and food industry. It is important to know the range of high-temperature brittleness in designing welding technology for constructions made of this steel type. There is no data in literature concerning this issue. High-temperature brittleness tests using the simulator of heat flow device Gleeble 3800 were performed. The tests results allowed the evaluation of the characteristic temperatures in the brittleness temperature range during the joining of duplex steels, specifically the nil-strength temperature (NST) and nil-ductility temperatures (NDT) during heating, the strength and ductility recovery temperatures (DRT) during cooling, the R f parameter (R f = (T liquidus - NDT)/NDT) describing the duplex steel inclination for hot cracking, and the brittleness temperature range (BTR). It has been stated that, for the examined steel, this range is wide and amounts to ca. 90 deg. C. The joining of duplex steels with the help of welding techniques creates a significant risk of hot cracks. After analysis of the DTA curves a liquidus temperature of T L = 1465 deg. C and a solidus temperature of T S = 1454 deg. C were observed. For NST a mean value was assumed, in which the cracks appeared for six samples; the temperature was 1381 deg. C. As the value of the NDT temperature 1367 deg. C was applied while for DRT the assumed temperature was 1375 deg. C. The microstructure of the fractures was observed using a Hitachi S-3400N scanning electron microscope (SEM). The analyses of the chemical composition were performed using an energy-dispersive X-ray spectrometer (EDS), Noran System Six of Thermo Fisher Scientific. Essential differences of fracture morphology type over the brittle temperature range were observed and described.

Crystallization and preliminary X-ray diffraction data of an LNA 7-mer duplex derived from a ricin aptamer

International Nuclear Information System (INIS)

Förster, Charlotte; Oberthuer, Dominik; Gao, Jiang; Eichert, André; Quast, Frederick G.; Betzel, Christian; Nitsche, Andreas; Erdmann, Volker A.; Fürste, Jens P.

2009-01-01

An all-LNA duplex was designed from the stem region of an RNA aptamer which has been generated against ricin. The LNA duplex was crystallized and preliminary X-ray diffraction analysis revealed diffraction to a resolution of up to 2.8 Å. Locked nucleic acids (LNAs) are modified nucleic acids which contain a modified sugar such as β-d-2′-O,4′-C methylene-bridged ribofuranose or other sugar derivatives in LNA analogues. The β-d-2′-O,4′-C methylene ribofuranose LNAs in particular possess high stability and melting temperatures, which makes them of interest for stabilizing the structure of different nucleic acids. Aptamers, which are DNAs or RNAs targeted against specific ligands, are candidates for substitution with LNAs in order to increase their stability. A 7-mer helix derived from the terminal part of an aptamer that was targeted against ricin was chosen. The ricin aptamer originally consisted of natural RNA building blocks and showed high affinity in ricin binding. For future stabilization of the aptamer, the terminal helix has been constructed as an ‘all-locked’ LNA and was successfully crystallized in order to investigate its structural properties. Optimization of crystal growth succeeded by the use of different metal salts as additives, such as CuCl 2 , MgCl 2 , MnCl 2 , CaCl 2 , CoCl 2 and ZnSO 4 . Preliminary X-ray diffraction data were collected and processed to 2.8 Å resolution. The LNA crystallized in space group P6 5 , with unit-cell parameters a = 50.11, b = 50.11, c = 40.72 Å. The crystals contained one LNA helix per asymmetric unit with a Matthews coefficient of 3.17 Å 3 Da −1 , which implies a solvent content of 70.15%

Microstructure and Antiwear Property of Laser Cladding Ni-Co Duplex Coating on Copper.

Science.gov (United States)

Wang, Yiyong; Liang, Zhipeng; Zhang, Junwei; Ning, Zhe; Jin, Hui

2016-07-28

Ni-Co duplex coatings were cladded onto Cu to improve the antiwear properties of Cu products. Prior to laser cladding, n-Al₂O₃/Ni layers were introduced as interlayers between laser cladding coatings and Cu substrates to improve the laser absorptivity of these substrates and ensure defect-free laser cladding coatings. The structure and morphology of the coatings were characterized by scanning electron microscopy and optical microscopy, and the phases of the coatings were analyzed by X-ray diffraction. Their hardness was measured using a microhardness tester. Experimental results showed that defect-free composite coatings were obtained and that the coatings were metallurgically bonded to the substrates. The surface of the Ni-Co duplex coatings comprised a Co-based solid solution, Cr₇C₃, (Fe,Ni) 23 C₆, and other strengthening phases. The microhardness and wear resistance of the duplex coatings were significantly improved compared with the Cu substrates. The average microhardness of the cladded coatings was 845.6 HV, which was approximately 8.2 times greater than that of the Cu substrates (102.6 HV). The volume loss of the Cu substrates was approximately 7.5 times greater than that of the Ni-Co duplex coatings after 60 min of sliding wear testing. The high hardness of and lack of defects in the Ni-Co duplex coatings reduced the plastic deformation and adhesive wear of the Cu substrates, resulting in improved wear properties.

Microstructure and Antiwear Property of Laser Cladding Ni–Co Duplex Coating on Copper

Science.gov (United States)

Wang, Yiyong; Liang, Zhipeng; Zhang, Junwei; Ning, Zhe; Jin, Hui

2016-01-01

Ni–Co duplex coatings were cladded onto Cu to improve the antiwear properties of Cu products. Prior to laser cladding, n-Al2O3/Ni layers were introduced as interlayers between laser cladding coatings and Cu substrates to improve the laser absorptivity of these substrates and ensure defect-free laser cladding coatings. The structure and morphology of the coatings were characterized by scanning electron microscopy and optical microscopy, and the phases of the coatings were analyzed by X-ray diffraction. Their hardness was measured using a microhardness tester. Experimental results showed that defect-free composite coatings were obtained and that the coatings were metallurgically bonded to the substrates. The surface of the Ni–Co duplex coatings comprised a Co-based solid solution, Cr7C3, (Fe,Ni)23C6, and other strengthening phases. The microhardness and wear resistance of the duplex coatings were significantly improved compared with the Cu substrates. The average microhardness of the cladded coatings was 845.6 HV, which was approximately 8.2 times greater than that of the Cu substrates (102.6 HV). The volume loss of the Cu substrates was approximately 7.5 times greater than that of the Ni–Co duplex coatings after 60 min of sliding wear testing. The high hardness of and lack of defects in the Ni–Co duplex coatings reduced the plastic deformation and adhesive wear of the Cu substrates, resulting in improved wear properties. PMID:28773755

Microstructure and Antiwear Property of Laser Cladding Ni–Co Duplex Coating on Copper

Directory of Open Access Journals (Sweden)

Yiyong Wang

2016-07-01

Full Text Available Ni–Co duplex coatings were cladded onto Cu to improve the antiwear properties of Cu products. Prior to laser cladding, n-Al2O3/Ni layers were introduced as interlayers between laser cladding coatings and Cu substrates to improve the laser absorptivity of these substrates and ensure defect-free laser cladding coatings. The structure and morphology of the coatings were characterized by scanning electron microscopy and optical microscopy, and the phases of the coatings were analyzed by X-ray diffraction. Their hardness was measured using a microhardness tester. Experimental results showed that defect-free composite coatings were obtained and that the coatings were metallurgically bonded to the substrates. The surface of the Ni–Co duplex coatings comprised a Co-based solid solution, Cr7C3, (Fe,Ni23C6, and other strengthening phases. The microhardness and wear resistance of the duplex coatings were significantly improved compared with the Cu substrates. The average microhardness of the cladded coatings was 845.6 HV, which was approximately 8.2 times greater than that of the Cu substrates (102.6 HV. The volume loss of the Cu substrates was approximately 7.5 times greater than that of the Ni–Co duplex coatings after 60 min of sliding wear testing. The high hardness of and lack of defects in the Ni–Co duplex coatings reduced the plastic deformation and adhesive wear of the Cu substrates, resulting in improved wear properties.

The Effect of Small Cosolutes that Mimic Molecular Crowding Conditions on the Stability of Triplexes Involving Duplex DNA

Directory of Open Access Journals (Sweden)

Anna Aviñó

2016-02-01

Full Text Available Triplex stability is studied in crowding conditions using small cosolutes (ethanol, acetonitrile and dimethylsulfoxide by ultraviolet (UV, circular dichroism (CD and nuclear magnetic resonance (NMR spectroscopies. The results indicate that the triplex is formed preferentially when the triplex forming oligonucleotide (TFO is RNA. In addition, DNA triplexes (D:D·D are clearly less stable in cosolute solutions while the stability of the RNA triplexes (R:D·D is only slightly decreased. The kinetic of triplex formation with RNA-TFO is slower than with DNA-TFO and the thermal stability of the triplex is increased with the salt concentration in EtOH-water solutions. Accordingly, RNA could be considered a potential molecule to form a stable triplex for regulatory purposes in molecular crowding conditions.

A duplex DNA-gold nanoparticle probe composed as a colorimetric biosensor for sequence-specific DNA-binding proteins.

Science.gov (United States)

Ahn, Junho; Choi, Yeonweon; Lee, Ae-Ree; Lee, Joon-Hwa; Jung, Jong Hwa

2016-03-21

Using duplex DNA-AuNP aggregates, a sequence-specific DNA-binding protein, SQUAMOSA Promoter-binding-Like protein 12 (SPL-12), was directly determined by SPL-12-duplex DNA interaction-based colorimetric actions of DNA-Au assemblies. In order to prepare duplex DNA-Au aggregates, thiol-modified DNA 1 and DNA 2 were attached onto the surface of AuNPs, respectively, by the salt-aging method and then the DNA-attached AuNPs were mixed. Duplex-DNA-Au aggregates having the average size of 160 nm diameter and the maximum absorption at 529 nm were able to recognize SPL-12 and reached the equivalent state by the addition of ∼30 equivalents of SPL-12 accompanying a color change from red to blue with a red shift of the maximum absorption at 570 nm. As a result, the aggregation size grew to about 247 nm. Also, at higher temperatures of the mixture of duplex-DNA-Au aggregate solution and SPL-12, the equivalent state was reached rapidly. On the contrary, in the control experiment using Bovine Serum Albumin (BSA), no absorption band shift of duplex-DNA-Au aggregates was observed.

The Role of Duplex Scanning in the Selection of Patients with Critical Lower-Limb Ischemia for Infrainguinal Percutaneous Transluminal Angioplasty

International Nuclear Information System (INIS)

Loefberg, Anne-Marie; Karacagil, Sadettin; Hellberg, Anders; Bostroem, Annika; Ljungman, Christer; Ostholm, Goerel

2001-01-01

Purpose: To investigate the role of duplex scanning in the selection of patients with critical lower-limb ischemia (CLI) for infrainguinal percutaneous transluminal angioplasty (PTA).Methods: One hundred and sixty-two limbs with CLI (150 patients) that underwent duplex scanning within 3 months prior to conventional diagnostic angiography (n = 88) or infrainguinal PTA (n = 74) were retrospectively studied. The findings obtained from duplex scanning and angiography were analyzed in a masked fashion by two different investigators.Results: The accuracy, sensitivity, specificity, and negative and positive predictive values of duplex scanning in the selection of patients for infrainguinal PTA were 86%, 84%, 89%, 86%, and 87% respectively. Forty-two procedures (57%) were performed at multiple arterial segments. The accuracy of duplex scanning in the selection of femoropopliteal and crural lesions for PTA was over 85%. However, the sensitivity of duplex scanning in the selection of popliteal and crural lesions for PTA was 49% and 38% respectively, compared with 80% for superior femoral artery lesions. In 39% of patients who were correctly selected for PTA, duplex scanning misdiagnosed one of the multiple lesions treated by PTA.Conclusion: Duplex scanning can safely be used for the selection of patients for infrainguinal PTA. The sensitivity of duplex scanning in the selection of lesions for PTA was less satisfactory in the popliteal and crural arteries compared with the femoropopliteal arteries

Duplex geometry: an example from the Moine Thrust Belt

Science.gov (United States)

Bowler, S.

1987-04-01

The geometry and microstructure of a small duplex formed in one bed from the Moine Thrust Belt of northwest Scotland is reported. The structure is seen in oblique section, within the Cambrian Pipe-rock, in an area of low strain. A range of movement direction indicators are present in the structure. An early grain shape fabric developed close to the roof thrust is taken as the best estimate of the overall movement direction towards 287°. Slickensides in the gouge developed on movement planes within the duplex show varied orientations on a given plane, and are not considered useful indicators of thrust transport direction. Branch lines exposed converge and diverge, suggesting little lateral continuity of the exposed structure. The microstructures present within the structure indicate an increase in localised deformation, and in cataclastic behavior as the duplex evolved. Early layer parallel shear is ubiquitous, giving rise to an elongate grain shape fabric close to bedding surfaces. In early formed horses, a layer-parallel, oblate grain shape fabric, which shows localised slip zones, is overprinted by gouge formation. Later formed horses show only fracturing and gouge development. This sequence is attributed to stick-slip behavior in the propagation or displacement of the original fault, now the floor thrust.

Microstructures and mechanical properties of duplex low carbon steel

Science.gov (United States)

Alfirano; Eben, U. S.; Hidayat, M.

2018-04-01

The microstructures behavior of duplex cold-rolled low carbon steel for automotive applications has been investigated. Intercritical annealing treatment is commonly used to develop a duplex low carbon steel containing ferrite and martensite. To get a duplex phase ferrite and martensite, the specimens were heated at inter-critical annealing temperature of 775°C - 825°C, for heating time up to 20 minutes, followed by water-quenched. The hardness of specimens was studied. The optical microscopy was used to analyze the microstructures. The optimal annealing conditions (martensite volume fraction approaching 20%) at 775°C with a heating time of 10 minutes was achieved. The highest hardness value was obtained in cold-rolled specimens of 41% in size reduction for intercritical annealing temperature of 825°C. In this condition, the hardness value was 373 HVN. The correlation between intercritical annealing temperature and time can be expressed in the transformation kinetics as fγ/fe = 1-exp(-Ktn) wherein K and n are grain growth rate constant and Avrami’s exponent, respectively. From experiment, the value of K = 0.15 and n = 0.461. Using the relationship between temperatures and heating time, activation energy (Q) can be calculated that is 267 kJ/mol.

Cytoplasmic Control of Sense-Antisense mRNA Pairs

Directory of Open Access Journals (Sweden)

Flore Sinturel

2015-09-01

Full Text Available Transcriptome analyses have revealed that convergent gene transcription can produce many 3′-overlapping mRNAs in diverse organisms. Few studies have examined the fate of 3′-complementary mRNAs in double-stranded RNA-dependent nuclear phenomena, and nothing is known about the cytoplasmic destiny of 3′-overlapping messengers or their impact on gene expression. Here, we demonstrate that the complementary tails of 3′-overlapping mRNAs can interact in the cytoplasm and promote post-transcriptional regulatory events including no-go decay (NGD in Saccharomyces cerevisiae. Genome-wide experiments confirm that these messenger-interacting mRNAs (mimRNAs form RNA duplexes in wild-type cells and thus have potential roles in modulating the mRNA levels of their convergent gene pattern under different growth conditions. We show that the post-transcriptional fate of hundreds of mimRNAs is controlled by Xrn1, revealing the extent to which this conserved 5′-3′ cytoplasmic exoribonuclease plays an unexpected but key role in the post-transcriptional control of convergent gene expression.

Cytoplasmic Control of Sense-Antisense mRNA Pairs.

Science.gov (United States)

Sinturel, Flore; Navickas, Albertas; Wery, Maxime; Descrimes, Marc; Morillon, Antonin; Torchet, Claire; Benard, Lionel

2015-09-22

Transcriptome analyses have revealed that convergent gene transcription can produce many 3'-overlapping mRNAs in diverse organisms. Few studies have examined the fate of 3'-complementary mRNAs in double-stranded RNA-dependent nuclear phenomena, and nothing is known about the cytoplasmic destiny of 3'-overlapping messengers or their impact on gene expression. Here, we demonstrate that the complementary tails of 3'-overlapping mRNAs can interact in the cytoplasm and promote post-transcriptional regulatory events including no-go decay (NGD) in Saccharomyces cerevisiae. Genome-wide experiments confirm that these messenger-interacting mRNAs (mimRNAs) form RNA duplexes in wild-type cells and thus have potential roles in modulating the mRNA levels of their convergent gene pattern under different growth conditions. We show that the post-transcriptional fate of hundreds of mimRNAs is controlled by Xrn1, revealing the extent to which this conserved 5'-3' cytoplasmic exoribonuclease plays an unexpected but key role in the post-transcriptional control of convergent gene expression. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Domain motions of Argonaute, the catalytic engine of RNA interference

Directory of Open Access Journals (Sweden)

Wall Michael E

2007-11-01

Full Text Available Abstract Background The Argonaute protein is the core component of the RNA-induced silencing complex, playing the central role of cleaving the mRNA target. Visual inspection of static crystal structures already has enabled researchers to suggest conformational changes of Argonaute that might occur during RNA interference. We have taken the next step by performing an all-atom normal mode analysis of the Pyrococcus furiosus and Aquifex aeolicus Argonaute crystal structures, allowing us to quantitatively assess the feasibility of these conformational changes. To perform the analysis, we begin with the energy-minimized X-ray structures. Normal modes are then calculated using an all-atom molecular mechanics force field. Results The analysis reveals low-frequency vibrations that facilitate the accommodation of RNA duplexes – an essential step in target recognition. The Pyrococcus furiosus and Aquifex aeolicus Argonaute proteins both exhibit low-frequency torsion and hinge motions; however, differences in the overall architecture of the proteins cause the detailed dynamics to be significantly different. Conclusion Overall, low-frequency vibrations of Argonaute are consistent with mechanisms within the current reaction cycle model for RNA interference.

Design of duplex low carbon steels for improved strength: weight applications

Energy Technology Data Exchange (ETDEWEB)

Koo, J.

1977-08-01

Duplex ferrite-martensite (DFM) steels with excellent combinations of strength and formability have been selected from first principles, and their microstructure-property relationships established through a systematic investigation of a series of ternary Fe/X/0.1 C steels (X being varying amount of Cr and Si). Duplex processing consists of initial austenitization and quenching to form 100% martensite, followed by annealing in the (..cap alpha.. + ..gamma..) range and subsequent quenching. The resultant DFM morphology is controlled by the type and amount of alloying element X.

Residual stresses and fatigue in a duplex stainless steel

International Nuclear Information System (INIS)

Johansson, Johan

1999-01-01

Duplex stainless steels, consisting of approximately equal amounts of austenite and ferrite, often combine the best features of austenitic and ferritic stainless steels. They generally have good mechanical properties, including high strength and ductility, and the corrosion resistance is often better than conventional austenitic grades. This has lead to a growing use of duplex stainless steels as a material in mechanically loaded constructions. However, detailed knowledge regarding its mechanical properties and deformation mechanisms are still lacking. In this thesis special emphasis has been placed on the residual stresses and their influence on mechanical behaviour of duplex stainless steels. Due to the difference in coefficient of thermal expansion between the two phases, tensile microstresses are found in the austenitic phase and balancing compressive microstresses in the ferritic phase. The first part of this thesis is a literature survey, which will give an introduction to duplex stainless steels and review the fatigue properties of duplex stainless steels and the influence of residual stresses in two-phase material. The second part concerns the evolution of the residual stress state during uniaxial loading. Initial residual stresses were found to be almost two times higher in the transverse direction compared to the rolling direction. During loading the absolute value of the microstresses increased in the macroscopic elastic regime but started to decrease with increasing load in the macroscopic plastic regime. A significant increase of the microstresses was also found to occur during unloading. Finite element simulations also show stress variation within one phase and a strong influence of both the elastic and plastic anisotropy of the individual phases on the simulated stress state. In the third part, the load sharing between the phases during cyclic loading is studied. X-ray diffraction stress analysis and transmission electron microscopy show that even if

Residual stresses and fatigue in a duplex stainless steel

Energy Technology Data Exchange (ETDEWEB)

Johansson, Johan

1999-05-01

Duplex stainless steels, consisting of approximately equal amounts of austenite and ferrite, often combine the best features of austenitic and ferritic stainless steels. They generally have good mechanical properties, including high strength and ductility, and the corrosion resistance is often better than conventional austenitic grades. This has lead to a growing use of duplex stainless steels as a material in mechanically loaded constructions. However, detailed knowledge regarding its mechanical properties and deformation mechanisms are still lacking. In this thesis special emphasis has been placed on the residual stresses and their influence on mechanical behaviour of duplex stainless steels. Due to the difference in coefficient of thermal expansion between the two phases, tensile microstresses are found in the austenitic phase and balancing compressive microstresses in the ferritic phase. The first part of this thesis is a literature survey, which will give an introduction to duplex stainless steels and review the fatigue properties of duplex stainless steels and the influence of residual stresses in two-phase material. The second part concerns the evolution of the residual stress state during uniaxial loading. Initial residual stresses were found to be almost two times higher in the transverse direction compared to the rolling direction. During loading the absolute value of the microstresses increased in the macroscopic elastic regime but started to decrease with increasing load in the macroscopic plastic regime. A significant increase of the microstresses was also found to occur during unloading. Finite element simulations also show stress variation within one phase and a strong influence of both the elastic and plastic anisotropy of the individual phases on the simulated stress state. In the third part, the load sharing between the phases during cyclic loading is studied. X-ray diffraction stress analysis and transmission electron microscopy show that even if

Phase transformations evaluation on a UNS S31803 duplex stainless steel based on nondestructive testing

International Nuclear Information System (INIS)

Macedo Silva, Edgard de; Costa de Albuquerque, Victor Hugo; Pereira Leite, Josinaldo; Gomes Varela, Antonio Carlos; Pinho de Moura, Elineudo; Tavares, Joao Manuel R.S.

2009-01-01

Duplex stainless steel presents special mechanical properties such as, for example, mechanical and corrosion strength, becoming competitive in relation to the other types of stainless steel. One of the great problems of duplex stainless steel microstructural changes study is related to embrittlement above 300 deg. C, with the precipitation of the α' phase occurring over the ferritic microstructure. Aiming to characterise embrittlement of duplex stainless steel, hardening kinetics, from 425 to 475 deg. C, was analysed through the speed of sound, Charpy impact energy, X-ray diffraction, hardness and microscopy parameters. The presence of two hardening stages, detected through the speed of sound, was observed, one being of brittle characteristic and the other ductile. Moreover, the speed of sound showed a direct correlation with the material's hardness. Thus, it is concluded that the speed of sound is a promising nondestructive parameter to follow-up embrittlement in duplex stainless steel.

Increased Y-chromosome detection by SRY duplexing

DEFF Research Database (Denmark)

Hansen, Morten Høgh; Clausen, Frederik Banch; Dziegiel, Morten Hanefeld

2012-01-01

Determining fetal sex noninvasively is dependent of a robust assay. We designed a novel SRY assay and combined it with a SRY assay from literature forming a duplex assay with the same fluorescent dye to increase detection of Y-chromosome at low cell-free fetal DNA or chimeric DNA concentrations....

Large-scale identification of microRNA targets in murine Dgcr8-deficient embryonic stem cell lines.

Directory of Open Access Journals (Sweden)

Matthew P A Davis

Full Text Available Small RNAs such as microRNAs play important roles in embryonic stem cell maintenance and differentiation. A broad range of microRNAs is expressed in embryonic stem cells while only a fraction of their targets have been identified. We have performed large-scale identification of embryonic stem cell microRNA targets using a murine embryonic stem cell line deficient in the expression of Dgcr8. These cells are heavily depleted for microRNAs, allowing us to reintroduce specific microRNA duplexes and identify refined target sets. We used deep sequencing of small RNAs, mRNA expression profiling and bioinformatics analysis of microRNA seed matches in 3' UTRs to identify target transcripts. Consequently, we have identified a network of microRNAs that converge on the regulation of several important cellular pathways. Additionally, our experiments have revealed a novel candidate for Dgcr8-independent microRNA genesis and highlighted the challenges currently facing miRNA annotation.

Mechanical Deformation Behavior of Lean Duplex 329LA Steel

Energy Technology Data Exchange (ETDEWEB)

Yoon, Byung-Jun [Research Institute of Industrial Science and Technology, Pohang (Korea, Republic of); Choi, Jeom-Yong [POSCO Technical Research Lab., Pohang (Korea, Republic of); Park, Kyung-Tae [Hanvat National University, Daejeon (Korea, Republic of); Lee, Ho Seong [Kyungpook National University, Daegu (Korea, Republic of)

2015-09-15

The tensile response of Lean Duplex 329LA stainless steel was investigated over various strain rates. It was observed that the mechanical response, including in particular the total elongation of the tested alloy, was strongly affected by the strain rate. As the strain rate decreased from 10-1 s-1 to 10-4 s-1, the elongation increased. As the strain rate increased, the deformation mode in an austenite phase was dominated by dislocation glide, resulting in deterioration of the elongation. The substructure of the ferritic phase showed a dislocation cell structure, independent of the applied strain rate. The optimum mechanical properties of lean duplex stainless steel thus can be obtained by controlling the deformation mode in the austenitic phase.

Mechanical Deformation Behavior of Lean Duplex 329LA Steel

International Nuclear Information System (INIS)

Yoon, Byung-Jun; Choi, Jeom-Yong; Park, Kyung-Tae; Lee, Ho Seong

2015-01-01

The tensile response of Lean Duplex 329LA stainless steel was investigated over various strain rates. It was observed that the mechanical response, including in particular the total elongation of the tested alloy, was strongly affected by the strain rate. As the strain rate decreased from 10-1 s-1 to 10-4 s-1, the elongation increased. As the strain rate increased, the deformation mode in an austenite phase was dominated by dislocation glide, resulting in deterioration of the elongation. The substructure of the ferritic phase showed a dislocation cell structure, independent of the applied strain rate. The optimum mechanical properties of lean duplex stainless steel thus can be obtained by controlling the deformation mode in the austenitic phase.

Aging behaviour of 25Cr-17Mn high nitrogen duplex stainless steel

OpenAIRE

Machado, I. F.; Padilha, A. F.

2000-01-01

The precipitation behaviour of a nickel free stainless steel containing 25% chromium, 17% manganese and 0.54% nitrogen, with duplex ferritic-austenitic microstructure, was studied using several complementary techniques of microstructural analysis after aging heat treatments between 600 and 1 000 degrees C for periods of lime between 15 and 6 000 min. During aging heat treatments, ferrite was decomposed into sigma phase and austenite by a eutectoid reaction, like in the Fe-Cr-Ni duplex stainle...

Comparison of simulated and measured quantities of a duplex reactor

Energy Technology Data Exchange (ETDEWEB)

Koskela, M.; Kajava, M. [ABB Marine, Helsinki (Finland)

1997-12-31

The purpose of this article is to illustrate the use of an analog simulator as a design tool when designing new power electric equipment. The purpose of simulation is to predict the functionality of electrical equipment to be constructed. Duplex reactor is an electromagnetic device designed to reduce voltage harmonics and short circuit currents in the ship electrical network. In this report a comparison between simulated and measured electrical quantities of a duplex reactor has been made. The purpose of the measurements was to show the correct functioning of the reactor. The simulation results and the measured waveforms corresponds well to each other. (orig.) 4 refs.

Multispectroscopic and Theoretical Exploration of the Comparative Binding Aspects of Bioflavonoid Fisetin with Triple- and Double-Helical Forms of RNA.

Science.gov (United States)

Bhuiya, Sutanwi; Haque, Lucy; Goswami, Rapti; Das, Suman

2017-12-14

The interactions of RNA triplex (U.A*U) and duplex (A.U) with naturally occurring flavonoid fisetin (FTN) have been examined at pH 7.0 using various spectroscopic, viscometric, and theoretical studies. Experimental observations showed that the ligand binds with both double- and triple-helical forms of RNA, although the binding affinity is greater for the triplex structure (5.94 × 10 6 M -1 ) compared to that for the duplex counterpart (1.0 × 10 5 M -1 ). Thermal melting experiments revealed that the Hoogsteen base-paired third strand of triplex was stabilized to a greater extent (∼14 °C) compared with the Watson-Crick base-paired second strand (∼4 °C) in the presence of FTN. From fluorimetric study, we observed that U.A*U and A.U primarily bind to the photoproduced tautomer of FTN in the excited state. Steady-state and time-resolved anisotropy measurements illustrate considerable modulations of the spectroscopic properties of the tautomeric FTN within the RNA environment. Viscometric, fluorescence quenching, and thermal melting studies all together support the mode of binding to be intercalation. Theoretical study explains the experimental absorption and emission (dual fluorescence) behavior of FTN along with the excited-state intramolecular proton transfer process.

Characterization of duplex stainless steel weld metals obtained by hybrid plasma-gas metal arc welding

Directory of Open Access Journals (Sweden)

Koray Yurtisik

2013-09-01

Full Text Available Despite its high efficiency, autogenous keyhole welding is not well-accepted for duplex stainless steels because it causes excessive ferrite in as-welded duplex microstructure, which leads to a degradation in toughness and corrosion properties of the material. Combining the deep penetration characteristics of plasma arc welding in keyhole mode and metal deposition capability of gas metal arc welding, hybrid plasma - gas metal arc welding process has considered for providing a proper duplex microstructure without compromising the welding efficiency. 11.1 mm-thick standard duplex stainless steel plates were joined in a single-pass using this novel technique. Same plates were also subjected to conventional gas metal arc and plasma arc welding processes, providing benchmarks for the investigation of the weldability of the material. In the first place, the hybrid welding process enabled us to achieve less heat input compared to gas metal arc welding. Consequently, the precipitation of secondary phases, which are known to be detrimental to the toughness and corrosion resistance of duplex stainless steels, was significantly suppressed in both fusion and heat affected zones. Secondly, contrary to other keyhole techniques, proper cooling time and weld metal chemistry were achieved during the process, facilitating sufficient reconstructive transformation of austenite in the ferrite phase.

Concurrent infections of pseudorabies virus and porcine bocavirus in China detected by duplex nanoPCR.

Science.gov (United States)

Luo, Yakun; Liang, Lin; Zhou, Ling; Zhao, Kai; Cui, Shangjin

2015-07-01

Nanoparticle-assisted polymerase chain reaction (nanoPCR) is a novel method for the simple, rapid, and specific amplification of DNA and has been used to detect viruses. A duplex nanoPCR molecular detection system was developed to detect pseudorabies virus (PRV) and porcine bocavirus (PBoV). Primers were selected to target conserved regions within the PRV gE gene and the PBoV NS1 gene. Under optimized nanoPCR reaction conditions, two specific fragments of 316 bp (PRV) and 996 bp (PBoV) were amplified by the duplex nanoPCR with a detection limit of 6 copies for PRV and 95 copies for PBoV; no fragments were amplified when other porcine viruses were used as template. When used to test 550 clinical samples, the duplex nanoPRC assay and a conventional duplex PCR assay provided very similar results (98.1% consistency); single PRV infections, single PBoV infections, and concurrent PRV and PBoV infections were detected in 37%, 15%, and 9% of the samples, respectively. The results indicate that the novel duplex nanoPCR assay is useful for the rapid detection of PRV and PBoV in pigs. Copyright © 2015 Elsevier B.V. All rights reserved.

Comparison of protocols and RNA carriers for plasma miRNA isolation. Unraveling RNA carrier influence on miRNA isolation

Science.gov (United States)

Martos, Laura; Fernández-Pardo, Álvaro; Oto, Julia; Medina, Pilar; España, Francisco; Navarro, Silvia

2017-01-01

microRNAs are promising biomarkers in biological fluids in several diseases. Different plasma RNA isolation protocols and carriers are available, but their efficiencies have been scarcely compared. Plasma microRNAs were isolated using a phenol and column-based procedure and a column-based procedure, in the presence or absence of two RNA carriers (yeast RNA and MS2 RNA). We evaluated the presence of PCR inhibitors and the relative abundance of certain microRNAs by qRT-PCR. Furthermore, we analyzed the association between different isolation protocols, the relative abundance of the miRNAs in the sample, the GC content and the free energy of microRNAs. In all microRNAs analyzed, the addition of yeast RNA as a carrier in the different isolation protocols used gave lower raw Cq values, indicating higher microRNA recovery. Moreover, this increase in microRNAs recovery was dependent on their own relative abundance in the sample, their GC content and the free-energy of their own most stable secondary structure. Furthermore, the normalization of microRNA levels by an endogenous microRNA is more reliable than the normalization by plasma volume, as it reduced the difference in microRNA fold abundance between the different isolation protocols evaluated. Our thorough study indicates that a standardization of pre- and analytical conditions is necessary to obtain reproducible inter-laboratory results in plasma microRNA studies. PMID:29077772

Interference alignment for degrees of freedom improvement in 3-relay half-duplex systems

KAUST Repository

Park, Seongho

2011-12-01

In a half-duplex relaying, the capacity pre-log factor is a major drawback in spectral efficiency. This paper proposes a linear precoding scheme and an alternate relaying protocol in a dual-hop half-duplex system where three relays help the communication between the source and the destination. In our proposed scheme, we consider a phase incoherent method in relays in which the source alternately transmits message signals to the different relays. In addition, we propose a linear interference alignment scheme which can eliminate the inter-relay interference resulted from the phase incoherence of relaying. Based on our analysis of degrees of freedom and our simulation results, we show that our proposed scheme achieves additional degrees of freedom compared to the conventional half-duplex relaying. © 2011 IEEE.

Sequence distribution of acetaldehyde-derived N2-ethyl-dG adducts along duplex DNA.

Science.gov (United States)

Matter, Brock; Guza, Rebecca; Zhao, Jianwei; Li, Zhong-ze; Jones, Roger; Tretyakova, Natalia

2007-10-01

Acetaldehyde (AA) is the major metabolite of ethanol and may be responsible for an increased gastrointestinal cancer risk associated with alcohol beverage consumption. Furthermore, AA is one of the most abundant carcinogens in tobacco smoke and induces tumors of the respiratory tract in laboratory animals. AA binding to DNA induces Schiff base adducts at the exocyclic amino group of dG, N2-ethylidene-dG, which are reversible on the nucleoside level but can be stabilized by reduction to N2-ethyl-dG. Mutagenesis studies in the HPRT reporter gene and in the p53 tumor suppressor gene have revealed the ability of AA to induce G-->A transitions and A-->T transversions, as well as frameshift and splice mutations. AA-induced point mutations are most prominent at 5'-AGG-3' trinucleotides, possibly a result of sequence specific adduct formation, mispairing, and/or repair. However, DNA sequence preferences for the formation of acetaldehyde adducts have not been previously examined. In the present work, we employed a stable isotope labeling-HPLC-ESI+-MS/MS approach developed in our laboratory to analyze the distribution of acetaldehyde-derived N2-ethyl-dG adducts along double-stranded oligodeoxynucleotides representing two prominent lung cancer mutational "hotspots" and their surrounding DNA sequences. 1,7,NH 2-(15)N-2-(13)C-dG was placed at defined positions within DNA duplexes derived from the K-ras protooncogene and the p53 tumor suppressor gene, followed by AA treatment and NaBH 3CN reduction to convert N2-ethylidene-dG to N2-ethyl-dG. Capillary HPLC-ESI+-MS/MS was used to quantify N2-ethyl-dG adducts originating from the isotopically labeled and unlabeled guanine nucleobases and to map adduct formation along DNA duplexes. We found that the formation of N2-ethyl-dG adducts was only weakly affected by the local sequence context and was slightly increased in the presence of 5-methylcytosine within CG dinucleotides. These results are in contrast with sequence

Development of duplex real-time PCR for the detection of WSSV and PstDV1 in cultivated shrimp.

Science.gov (United States)

Leal, Carlos A G; Carvalho, Alex F; Leite, Rômulo C; Figueiredo, Henrique C P

2014-07-05

The White spot syndrome virus (WSSV) and Penaeus stylirostris penstyldensovirus 1 (previously named Infectious hypodermal and hematopoietic necrosis virus-IHHNV) are two of the most important viral pathogens of penaeid shrimp. Different methods have been applied for diagnosis of these viruses, including Real-time PCR (qPCR) assays. A duplex qPCR method allows the simultaneous detection of two viruses in the same sample, which is more cost-effective than assaying for each virus separately. Currently, an assay for the simultaneous detection of the WSSV and the PstDV1 in shrimp is unavailable. The aim of this study was to develop and standardize a duplex qPCR assay for the simultaneous detection of the WSSV and the PstDV1 in clinical samples of diseased L. vannamei. In addition, to evaluate the performance of two qPCR master mixes with regard to the clinical sensitivity of the qPCR assay, as well as, different methods for qPCR results evaluation. The duplex qPCR assay for detecting WSSV and PstDV1 in clinical samples was successfully standardized. No difference in the amplification of the standard curves was observed between the duplex and singleplex assays. Specificities and sensitivities similar to those of the singleplex assays were obtained using the optimized duplex qPCR. The analytical sensitivities of duplex qPCR were two copies of WSSV control plasmid and 20 copies of PstDV1 control plasmid. The standardized duplex qPCR confirmed the presence of viral DNA in 28 from 43 samples tested. There was no difference for WSSV detection using the two kits and the distinct methods for qPCR results evaluation. High clinical sensitivity for PstDV1 was obtained with TaqMan Universal Master Mix associated with relative threshold evaluation. Three cases of simultaneous infection by the WSSV and the PstDV1 were identified with duplex qPCR. The standardized duplex qPCR was shown to be a robust, highly sensitive, and feasible diagnostic tool for the simultaneous detection of the

The first example of a Hoogsteen base-paired DNA duplex in dynamic equilibrium with a Watson-Crick base-paired duplex--a structural (NMR), kinetic and thermodynamic study.

Science.gov (United States)

Isaksson, J; Zamaratski, E; Maltseva, T V; Agback, P; Kumar, A; Chattopadhyaya, J

2001-06-01

A single-point substitution of the O4' oxygen by a CH2 group at the sugar residue of A6 (i.e. 2'-deoxyaristeromycin moiety) in a self-complementary DNA duplex, 5'-d(C1G2C3G4A5A6T7T8C9G10C11G12)2(-3), has been shown to steer the fully Watson-Crick basepaired DNA duplex (1A), akin to the native counterpart, to a doubly A6:T7 Hoogsteen basepaired (1B) B-type DNA duplex, resulting in a dynamic equilibrium of (1A)(1B): Keq = k1/k(-1) = 0.56+/-0.08. The dynamic conversion of the fully Watson-Crick basepaired (1A) to the partly Hoogsteen basepaired (1B) structure is marginally kinetically and thermodynamically disfavoured [k1 (298K) = 3.9 0.8 sec(-1); deltaHdegrees++ = 164+/-14 kJ/mol; -TdeltaS degrees++ (298K) = -92 kJ/mol giving a deltaG degrees++ 298 of 72 kJ/mol. Ea (k1) = 167 14 kJ/mol] compared to the reverse conversion of the Hoogsteen (1B) to the Watson-Crick (1A) structure [k-1 (298K) = 7.0 0.6 sec-1, deltaH degrees++ = 153 13 kJ/mol; -TdeltaSdegrees++ (298K) = -82 kJ/mol giving a deltaGdegrees++(298) of 71 kJ/mol. Ea (k-1) = 155 13 kJ/mol]. Acomparison of deltaGdegrees++(298) of the forward (k1) and backward (k-1) conversions, (1A)(1B), shows that there is ca 1 kJ/mol preference for the Watson-Crick (1A) over the double Hoogsteen basepaired (1B) DNA duplex, thus giving an equilibrium ratio of almost 2:1 in favour of the fully Watson-Crick basepaired duplex. The chemical environments of the two interconverting DNA duplexes are very different as evident from their widely separated sets of chemical shifts connected by temperature-dependent exchange peaks in the NOESY and ROESY spectra. The fully Watson-Crick basepaired structure (1A) is based on a total of 127 intra, 97 inter and 17 cross-strand distance constraints per strand, whereas the double A6:T7 Hoogsteen basepaired (1B) structure is based on 114 intra, 92 inter and 15 cross-strand distance constraints, giving an average of 22 and 20 NOE distance constraints per residue and strand, respectively. In addition

Phase transformations evaluation on a UNS S31803 duplex stainless steel based on nondestructive testing

Energy Technology Data Exchange (ETDEWEB)

Macedo Silva, Edgard de, E-mail: edgard@cefetpb.edu.br [Centro federal de Educacao Tecnologica da Paraiba (CEFET PB), Area da Industria, Avenida 1o de Maio, 720 - 58015-430 - Joao Pessoa/PB (Brazil); Costa de Albuquerque, Victor Hugo, E-mail: victor.albuquerque@fe.up.pt [Universidade Federal da Paraiba (UFPB), Departamento de Engenharia Mecanica (DEM), Cidade Universitaria, S/N - 58059-900 - Joao Pessoa/PB (Brazil); Pereira Leite, Josinaldo, E-mail: josinaldo@ct.ufpb.br [Universidade Federal da Paraiba (UFPB), Departamento de Engenharia Mecanica (DEM), Cidade Universitaria, S/N - 58059-900 - Joao Pessoa/PB (Brazil); Gomes Varela, Antonio Carlos, E-mail: varela@cefetpb.edu.br [Universidade Federal da Paraiba (UFPB), Departamento de Engenharia Mecanica (DEM), Cidade Universitaria, S/N - 58059-900 - Joao Pessoa/PB (Brazil); Pinho de Moura, Elineudo, E-mail: elineudo@pq.cnpq.br [Universidade Federal do Ceara (UFC), Departamento de Engenharia Metalurgica e de Materiais, Campus do Pici, Bloco 715, 60455-760 - Fortaleza/CE (Brazil); Tavares, Joao Manuel R.S., E-mail: tavares@fe.up.pt [Faculdade de Engenharia da Universidade do Porto (FEUP), Departamento de Engenharia Mecanica e Gestao Industrial (DEMEGI)/Instituto de Engenharia Mecanica e Gestao Industrial - INEGI, Rua Dr. Roberto Frias, s/n, 4200-465 Porto (Portugal)

2009-08-15

Duplex stainless steel presents special mechanical properties such as, for example, mechanical and corrosion strength, becoming competitive in relation to the other types of stainless steel. One of the great problems of duplex stainless steel microstructural changes study is related to embrittlement above 300 deg. C, with the precipitation of the {alpha}' phase occurring over the ferritic microstructure. Aiming to characterise embrittlement of duplex stainless steel, hardening kinetics, from 425 to 475 deg. C, was analysed through the speed of sound, Charpy impact energy, X-ray diffraction, hardness and microscopy parameters. The presence of two hardening stages, detected through the speed of sound, was observed, one being of brittle characteristic and the other ductile. Moreover, the speed of sound showed a direct correlation with the material's hardness. Thus, it is concluded that the speed of sound is a promising nondestructive parameter to follow-up embrittlement in duplex stainless steel.

Development and test evaluation of duplex steam reformer tube

International Nuclear Information System (INIS)

Allen, D.C.; Meyer, D.J.; Pflasterer, G.R.

1980-01-01

For HTR applications involving a steam reformer (SR), it is uncertain whether an intermediate heat exchanger (IHX) is required. There are several system configurations that could be developed for the application of nuclear heat using the steam reformer reaction. The considerations (advantages vs. disadvantages) for each of the system configurations are summarized. The approach that technically and economically appears to be the most attractive, in studies conducted by General Electric, combines the SR process heat exchanger and the IHX in a single component using a duplex tube. A central question concerning the duplex tube concept is whether the design would provide adequate leak monitoring capability and significant reduction in tritium and hydrogen diffusion, while introducing only a small increase in overall temperature difference from the helium to the process gas. A cooperative GE-KFA effort was undertaken to develop, fabricate, test, and evaluate a duplex steam reformer tube. GE was responsible for the development and fabrication of the tube, and KFA was responsible for testing the tube in the EVA I facility at Juelich. Both GE and KFA are evaluating the thermochemical and metallurgical test data. Actual fabrication of the tube was performed by Foster-Wheeler in accordance with the GE design. This paper reviews the highlights of the fabrication development and preliminary evaluation of the test data

Listen and talk full-duplex cognitive radio networks

CERN Document Server

Liao, Yun; Han, Zhu

2016-01-01

This brief focuses on the use of full-duplex radio in cognitive radio networks, presenting a novel spectrum sharing protocol that allows the secondary users to simultaneously sense and access the vacant spectrum. This protocol, called “Listen-and-talk” (LAT), is evaluated by both mathematical analysis and computer simulations in comparison with other existing protocols, including the listen-before-talk protocol. In addition to LAT-based signal processing and resource allocation, the brief discusses techniques such as spectrum sensing and dynamic spectrum access. The brief proposes LAT as a suitable access scheme for cognitive radio networks, which can support the quality-of-service requirements of these high priority applications. Fundamental theories and key techniques of cognitive radio networks are also covered. Listen and Talk: Full-duplex Cognitive Radio Networks is designed for researchers, developers, and professionals involved in cognitive radio networks. Advanced-level students studying signal pr...

Mycobacterium smegmatis Lhr Is a DNA-dependent ATPase and a 3'-to-5' DNA translocase and helicase that prefers to unwind 3'-tailed RNA:DNA hybrids.

Science.gov (United States)

Ordonez, Heather; Shuman, Stewart

2013-05-17

We are interested in the distinctive roster of helicases of Mycobacterium, a genus of the phylum Actinobacteria that includes the human pathogen Mycobacterium tuberculosis and its avirulent relative Mycobacterium smegmatis. Here, we identify and characterize M. smegmatis Lhr as the exemplar of a novel clade of superfamily II helicases, by virtue of its biochemical specificities and signature domain organization. Lhr is a 1507-amino acid monomeric nucleic acid-dependent ATPase that uses the energy of ATP hydrolysis to drive unidirectional 3'-to-5' translocation along single strand DNA and to unwind duplexes en route. The ATPase is more active in the presence of calcium than magnesium. ATP hydrolysis is triggered by either single strand DNA or single strand RNA, yet the apparent affinity for a DNA activator is 11-fold higher than for an RNA strand of identical size and nucleobase sequence. Lhr is 8-fold better at unwinding an RNA:DNA hybrid than it is at displacing a DNA:DNA duplex of identical nucleobase sequence. The truncated derivative Lhr-(1-856) is an autonomous ATPase, 3'-to-5' translocase, and RNA:DNA helicase. Lhr-(1-856) is 100-fold better RNA:DNA helicase than DNA:DNA helicase. Lhr homologs are found in bacteria representing eight different phyla, being especially prevalent in Actinobacteria (including M. tuberculosis) and Proteobacteria (including Escherichia coli).

Absolute and direct microRNA quantification using DNA-gold nanoparticle probes.

Science.gov (United States)

Degliangeli, Federica; Kshirsagar, Prakash; Brunetti, Virgilio; Pompa, Pier Paolo; Fiammengo, Roberto

2014-02-12

DNA-gold nanoparticle probes are implemented in a simple strategy for direct microRNA (miRNA) quantification. Fluorescently labeled DNA-probe strands are immobilized on PEGylated gold nanoparticles (AuNPs). In the presence of target miRNA, DNA-RNA heteroduplexes are formed and become substrate for the endonuclease DSN (duplex-specific nuclease). Enzymatic hydrolysis of the DNA strands yields a fluorescence signal due to diffusion of the fluorophores away from the gold surface. We show that the molecular design of our DNA-AuNP probes, with the DNA strands immobilized on top of the PEG-based passivation layer, results in nearly unaltered enzymatic activity toward immobilized heteroduplexes compared to substrates free in solution. The assay, developed in a real-time format, allows absolute quantification of as little as 0.2 fmol of miR-203. We also show the application of the assay for direct quantification of cancer-related miR-203 and miR-21 in samples of extracted total RNA from cell cultures. The possibility of direct and absolute quantification may significantly advance the use of microRNAs as biomarkers in the clinical praxis.

Hybrid recursive active filters for duplexing in RF transmitter front-ends

Science.gov (United States)

Gottardo, Giuseppe; Donati, Giovanni; Musolff, Christian; Fischer, Georg; Felgentreff, Tilman

2016-08-01

Duplex filters in modern base transceiver stations shape the channel in order to perform common frequency division duplex operations. Usually, they are designed as cavity filters, which are expensive and have large dimensions. Thanks to the emerging digital technology and fast digital converters, it is possible to transfer the efforts of designing analog duplex filters into digital numeric algorithms applied to feedback structures, operating on power. This solution provides the shaping of the signal spectrum directly at the output of the radio frequency (RF) power amplifiers (PAs) relaxing the transmitter design especially in the duplexer and in the antenna sections. The design of a digital baseband feedback applied to the analog power RF amplifiers (hybrid filter) is presented and verified by measurements. A model to describe the hybrid system is investigated, and the relation between phase and resonance peaks of the resulting periodic band-pass transfer function is described. The stability condition of the system is analyzed using Nyquist criterion. A solution involving a number of digital feedback and forward branches is investigated defining the parameters of the recursive structure. This solution allows the closed loop system to show a periodic band pass with up to 500 kHz bandwidth at the output of the RF amplifier. The band-pass magnitude reaches up to 17 dB selectivity. The rejection of the PA noise in the out-of-band frequencies is verified by measurements. The filter is tested with a modulated LTE (Long Term Evolution) signal showing an ACPR (Adjacent Channel Power Ratio) enhancement of 10 dB of the transmitted signal.

Nonlinear physics approach to RNA cross-replication: Marginal stability, generalized logistic growth, and impacts of degradation

Energy Technology Data Exchange (ETDEWEB)

Frank, T.D., E-mail: till.frank@ucd.ie [UCD School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland); Systems Biology Ireland, University College Dublin, Belfield, Dublin 4 (Ireland); Center for the Ecological Study of Perception and Action, Department of Psychology, University of Connecticut, 406 Babbidge Road, Storrs, CT 06269 (United States)

2011-10-24

Highlights: → RNA cross-replication is a marginally stable but not asymptotically stable process. → RNA enzymes exhibits a generalized logistic growth pattern with exponent equal to 2. → Degradation results in non-symmetric saturation levels of cross-replicating RNAs. -- Abstract: It is nowadays believed that the evolution of life involved as an intermediate step an RNA world. In such an RNA world RNA molecules replicate themselves in catalytic reactions. Recent experiments on cross-replicating RNA support the RNA world hypothesis. We derive a nonlinear mass-action kinetics model to explain logistic growth patterns and non-symmetric saturation levels observed in those experiments. We also demonstrate that fixed points of the RNA growth process are only marginally stable rather than asymptotically stable.

Duplex-assisted carotid artery stenting without administration of contrast medium for patients with chronic kidney disease or allergic reaction.

Science.gov (United States)

Mizowaki, Takashi; Fujita, Atsushi; Imahori, Taichiro; Uyama, Atsushi; Inoue, Satoshi; Kohta, Masaaki; Hamaguchi, Hirotoshi; Sasayama, Takashi; Hosoda, Kohkichi; Kohmura, Eiji

2016-07-01

We aimed to investigate the safety and feasibility of duplex-assisted carotid artery stenting (CAS) without administration of contrast medium for the prevention of adverse reactions. Fifteen patients (9 % of all CASs) with severe carotid stenosis (≥70 %) associated with chronic kidney disease (CKD) (stage ≥3) or allergy to contrast medium underwent duplex-assisted CAS without administration of contrast medium over 4 years. The procedural success rate and perioperative complication rates were compared between the duplex-assisted CAS (n = 15) and conventional CAS (n = 153) groups. The technical success rate was 100 % in both groups. Combined stroke or death rates during the post-procedural period did not differ significantly between the duplex-assisted CAS group (0/15, 0 %) and conventional CAS group (4/153, 2.6 %). None of the 14 patients with CKD in the duplex-assisted CAS group experienced further deterioration of renal function. The mean surface radiation dose of participants in the duplex-assisted CAS group (n = 13, 312 ± 131 mGy) was significantly lower than that of the conventional CAS group (n = 31, 1036 ± 571 mGy) (p duplex-assisted CAS group (156 ± 39.7 min) and the conventional CAS group (156 ± 37.4 min). Duplex-assisted CAS without administration of contrast medium could be an alternative option in selected patients deemed to be at high risk for renal failure from nephrotoxic contrast medium or who have an allergy to contrast medium.

Thermal ageing of duplex stainless steels

International Nuclear Information System (INIS)

Massoud, J.P.; Van Duysen, J.C.; Zacharie, G.; Auger, P.; Danoix, F.

1992-03-01

The evolution of the mechanical properties of Mobearing anf Mo-free cast duplex stainless steels, induced by long term ageing in the range 300-400 deg C, has been studied in relation with the evolution of their microstructure. The unmixing of the ferritic Fe-Cr-Ni, solid solution by three-dimensional (sponge-like) spinodal decomposition and the precipitation of intermetallic G-phase particles are the main characteristics of this microstructural evolution

Comments on process of duplex coatings on aluminum alloys

Institute of Scientific and Technical Information of China (English)

Samir H.A.; QIAN Han-cheng(钱翰城); XIA Bo-cai(夏伯才); WU Shi-ming(吴仕明)

2004-01-01

Despite the great achievements made in improvement of wear resistance properties of aluminum alloys,their applications in heavy surface load-bearing are limited. Single coating is insufficient to produce the desired combination of surface properties. These problems can be solved through the duplex coatings. The aim of the present study is to overview the research advances on processes of duplex coatings on aluminum alloys combined with micro plasma oxidation process and with other modern processes such as physical vapour deposition and plasma assisted chemical vapour deposition and also to evaluate the performance of micro plasma oxidation coatings in improving the load-bearing, friction and wear resistance properties of aluminum alloys in comparison with other coatings. Wherein, a more detailed presentation of the processes and their performances and disadvantages are given as well.

Duplex surface treatment of AISI 1045 steel via plasma nitriding of chromized layer

International Nuclear Information System (INIS)

Hakami, F.; Sohi, M. Heydarzadeh; Ghani, J. Rasizadeh

2011-01-01

In this work AISI 1045 steel were duplex treated via plasma nitriding of chromized layer. Samples were pack chromized by using a powder mixture consisting of ferrochromium, ammonium chloride and alumina at 1273 K for 5 h. The samples were then plasma-nitrided for 5 h at 803 K and 823 K, in a gas mixture of 75%N 2 + 25%H 2 . The treated specimens were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis and Vickers micro-hardness test. The thickness of chromized layer before nitriding was about 8 μm and it was increased after plasma nitriding. According to XRD analysis, the chromized layer was composed of chromium and iron carbides. Plasma nitriding of chromized layer resulted in the formation of chromium and iron nitrides and carbides. The hardness of the duplex layers was significantly higher than the hardness of the base material or chromized layer. The main cause of the large improvement in surface hardness was due to the formation of Cr x N and Fe x N phases in the duplex treated layers. Increasing of nitriding temperature from 803 to 823 K enhanced the formation of CrN in the duplex treated layer and increased the thickness of the nitrided layer.

RNA Interference and its therapeutic applications

Directory of Open Access Journals (Sweden)

Srinivasa Rao T

2011-10-01

Full Text Available RNAi is a potent method, requiring only a few molecules of dsRNA per cell to silence the expression. Long molecules of double stranded RNA (dsRNA trigger the process. The dsRNA comes from virus and transposon activity in natural RNAi process, while it can be injected in the cells in experimental processes. The strand of the dsRNA that is identical in sequence to a region in target mRNA molecule is called the sense strand, and the other strand which is complimentary is termed the antisense strand. An enzyme complex called DICER thought to be similar to RNAase III then recognizes dsRNA, and cuts it into roughly 22- nucleotide long fragments. These fragments termed siRNAs for “small interfering RNAs” remain in double stranded duplexes with very short 3' overhangs. However, only one of the two strands, known as the guide strand or antisense strand binds the argonaute protein of RNA-induced silencing complex (RISC and target the complementary mRNA resulting gene silencing. The other anti-guide strand or passenger strand is degraded as a RISC substrate during the process of RISC activation. This form of RNAi is termed as post transcriptional gene silencing (PTGS; other forms are also thought to operate at the genomic or transcriptional level in some organisms. In mammals dsRNA longer than 30 base pairs induces a nonspecific antiviral response. This so-called interferon response results in a nonspecific arrest in translation and induction of apoptosis. This cascade induces a global non-specific suppression of translation, which in turn triggers apoptosis. Interestingly, dsRNAs less than 30 nt in length do not activate the antiviral response and specifically switched off genes in human cells without initiating the acute phase response. Thus these siRNAs are suitable for gene target validation and therapeutic applications in many species, including humans. [Vet. World 2011; 4(5.000: 225-229

Passivation of duplex stainless steel in solutions simulating chloride-contaminated concrete

Directory of Open Access Journals (Sweden)

Takenouti, H.

2007-12-01

Full Text Available Most studies published to date on the corrosion behaviour of stainless reinforcing steel are based on austenitic steel. The market presence of corrugated duplex steel is growing, however. The present study compared passivity in 2205 type duplex and 304 type austenitic stainless steel. Polarization tests in chloride-containing Ca(OH2 solutions confirmed the exceptional performance of duplex steels. X-ray photoelectronic spectroscopy (XPS showed that the passive layer generated on duplex stainless steel in media simulating concrete pore solutions had a higher Cr content than the layer formed on steel in contact with the air. The XPS results also revealed that in duplex steel the form adopted by the passive layer Fe oxides was Fe3O4 in the solutions simulating concrete, rather than Fe2O3, as in duplex steel exposed to air. Electrochemical impedance spectroscopy (EIS can be used to monitor the transformations taking place in the passive layer and analyze the factors involved.La mayoría de los estudios publicados hasta el momento sobre el comportamiento frente a la corrosión de armaduras de acero inoxidable se basan en aceros austeníticos. Sin embargo, la presencia en el mercado de aceros corrugados dúplex es cada vez más importante. En este trabajo se analiza la pasividad de un acero inoxidable dúplex tipo 2205 en comparación con la de un inoxidable austenítico tipo 304. Los ensayos de polarización en disoluciones de Ca(OH2 con cloruros confirman el excepcional comportamiento de los aceros dúplex. La espectroscopía fotoelectrónica de rayos X (XPS informa de que la capa pasiva generada en aceros inoxidables dúplex en medios que simulan la disolución de los poros del hormigón posee mayor contenido en óxidos de Cr que la formada en aire. También se puede deducir de los resultados de XPS que los óxidos de Fe de la capa pasiva de los aceros dúplex se encuentran en forma de Fe3O4 en las disoluciones que simulan el hormigón en vez de en

Fast prediction of RNA-RNA interaction using heuristic algorithm.

Science.gov (United States)

Montaseri, Soheila

2015-01-01

Interaction between two RNA molecules plays a crucial role in many medical and biological processes such as gene expression regulation. In this process, an RNA molecule prohibits the translation of another RNA molecule by establishing stable interactions with it. Some algorithms have been formed to predict the structure of the RNA-RNA interaction. High computational time is a common challenge in most of the presented algorithms. In this context, a heuristic method is introduced to accurately predict the interaction between two RNAs based on minimum free energy (MFE). This algorithm uses a few dot matrices for finding the secondary structure of each RNA and binding sites between two RNAs. Furthermore, a parallel version of this method is presented. We describe the algorithm's concurrency and parallelism for a multicore chip. The proposed algorithm has been performed on some datasets including CopA-CopT, R1inv-R2inv, Tar-Tar*, DIS-DIS, and IncRNA54-RepZ in Escherichia coli bacteria. The method has high validity and efficiency, and it is run in low computational time in comparison to other approaches.

Law of mixture used to model the flow behavior of a duplex stainless steel at high temperatures

International Nuclear Information System (INIS)

Momeni, A.; Dehghani, K.; Poletti, M.C.

2013-01-01

In this investigation the flow curves of a duplex stainless steel were drawn by performing hot compression tests over a wide temperature range of 950–1200 °C and strain rates of 0.001–100 s −1 . The flow curves of ferrite and austenite phases in the duplex structure were depicted by conducting similar hot compression tests on two steels that were cast and prepared with the same chemical compositions. The flow curves of the austenitic steel were found typical of dynamic recrystallization. They were successfully modeled by using the experimental exponential equation proposed by Cingara and McQueen. The flow curves of the ferritic steel were typical of dynamic recovery. They were modeled by the dislocation density evolution function proposed by Estrin and Meckning. Comparing the flow curves of three studied steels, it was found that the flow curves of the duplex steel were very similar and close to those of the ferrite steel. It was understood that in a duplex structure of ferrite and austenite the flow behavior is mostly controlled by the softer phase, i.e. ferrite. The law of mixture was modified to consider the strain partitioning between ferrite and austenite. The distribution coefficients of ferrite and austenite were described and determined at different deformation conditions. The results of modeling satisfactorily predicted the experimental curves. It was shown that the influence of austenite on the flow behavior of the duplex structure is almost low. However, it increases as strain rate or temperature rises. - Highlights: ► Flow curves of austenite and ferrite in the duplex steel were modeled separately. ► The flow behavior of the duplex steel is mostly controlled by ferrite. ► The effect of austenite on flow curve increases with temperature and strain rate. ► The flow curve of the duplex steel is modeled by the modified law of mixture

Contribution to the metallurgy of welding processes in stainless ferritic-austenitic (duplex) steels

International Nuclear Information System (INIS)

Perteneder, E.; Toesch, J.; Rabensteiner, G.

1989-01-01

Duplex steels have a ferritic austenitic structure. Therefore, to obtain a successful welding, special metallurgical regulations must be observed. The effect of energy per unit length and plate thickness onto the heat influence zone in case of manual arc welding is examined. Practice-oriented instructions for the welding technique to be applied are deduced from the results. Finally, the effect of the alloy composition onto the welding capacity of duplex steels is examined. (orig.) [de

A full-duplex CATV/wireless-over-fiber lightwave transmission system.

Science.gov (United States)

Li, Chung-Yi; Lu, Hai-Han; Ying, Cheng-Ling; Cheng, Chun-Jen; Lin, Che-Yu; Wan, Zhi-Wei; Chen, Jian-Hua

2015-04-06

A full-duplex CATV/wireless-over-fiber lightwave transmission system consisting of one broadband light source (BLS), two optical interleavers (ILs), one intensity modulator, and one phase modulator is proposed and experimentally demonstrated. The downstream light is optically promoted from 10Gbps/25GHz microwave (MW) data signal to 10Gbps/100GHz and 10Gbps/50GHz millimeter-wave (MMW) data signals in fiber-wireless convergence, and intensity-modulated with 50-550 MHz CATV signal. For up-link transmission, the downstream light is phase-remodulated with 10Gbps/25GHz MW data signal in fiber-wireless convergence. Over a 40-km single-mode fiber (SMF) and a 10-m radio frequency (RF) wireless transport, bit error rate (BER), carrier-to-noise ratio (CNR), composite second-order (CSO), and composite triple-beat (CTB) are observed to perform well in such full-duplex CATV/wireless-over-fiber lightwave transmission systems. This full-duplex 100-GHz/50-GHz/25-GHz/550-MHz lightwave transmission system is an attractive alternative. This transmission system not only presents its advancement in the integration of fiber backbone and CATV/wireless feeder networks, but also it provides the advantages of a communication channel for higher data rates and bandwidth.

Multi-shell model of ion-induced nucleic acid condensation

Energy Technology Data Exchange (ETDEWEB)

Tolokh, Igor S. [Department of Computer Science, Virginia Tech, Blacksburg, Virginia 24061 (United States); Drozdetski, Aleksander V. [Department of Physics, Virginia Tech, Blacksburg, Virginia 24061 (United States); Pollack, Lois [School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853-3501 (United States); Baker, Nathan A. [Advanced Computing, Mathematics, and Data Division, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912 (United States); Onufriev, Alexey V. [Department of Computer Science, Virginia Tech, Blacksburg, Virginia 24061 (United States); Department of Physics, Virginia Tech, Blacksburg, Virginia 24061 (United States)

2016-04-21

We present a semi-quantitative model of condensation of short nucleic acid (NA) duplexes induced by trivalent cobalt(III) hexammine (CoHex) ions. The model is based on partitioning of bound counterion distribution around single NA duplex into “external” and “internal” ion binding shells distinguished by the proximity to duplex helical axis. In the aggregated phase the shells overlap, which leads to significantly increased attraction of CoHex ions in these overlaps with the neighboring duplexes. The duplex aggregation free energy is decomposed into attractive and repulsive components in such a way that they can be represented by simple analytical expressions with parameters derived from molecular dynamic simulations and numerical solutions of Poisson equation. The attractive term depends on the fractions of bound ions in the overlapping shells and affinity of CoHex to the “external” shell of nearly neutralized duplex. The repulsive components of the free energy are duplex configurational entropy loss upon the aggregation and the electrostatic repulsion of the duplexes that remains after neutralization by bound CoHex ions. The estimates of the aggregation free energy are consistent with the experimental range of NA duplex condensation propensities, including the unusually poor condensation of RNA structures and subtle sequence effects upon DNA condensation. The model predicts that, in contrast to DNA, RNA duplexes may condense into tighter packed aggregates with a higher degree of duplex neutralization. An appreciable CoHex mediated RNA-RNA attraction requires closer inter-duplex separation to engage CoHex ions (bound mostly in the “internal” shell of RNA) into short-range attractive interactions. The model also predicts that longer NA fragments will condense more readily than shorter ones. The ability of this model to explain experimentally observed trends in NA condensation lends support to proposed NA condensation picture based on the multivalent �

Yield stress of duplex stainless steel specimens estimated using a compound Hall–Petch equation

Directory of Open Access Journals (Sweden)

Noriaki Hirota, Fuxing Yin, Tsukasa Azuma and Tadanobu Inoue

2010-01-01

Full Text Available In this study, the 0.2% yield stress of duplex stainless steel was evaluated using a compound Hall–Petch equation. The compound Hall–Petch equation was derived from four types of duplex stainless steel, which contained 0.2–64.4 wt% δ-ferrite phase, had different chemical compositions and were annealed at different temperatures. Intragranular yield stress was measured with an ultra-microhardness tester and evaluated with the yield stress model proposed by Dao et al. Grain size, volume fraction and texture were monitored by electron backscattering diffraction measurement. The kγ constant in the compound equation for duplex stainless steel agrees well with that for γ-phase SUS316L steel in the temperature range of 1323–1473 K. The derived compound Hall–Petch equation predicts that the yield stress will be in good agreement with the experimental results for the Cr, Mn, Si, Ni and N solid-solution states. We find that the intragranular yield stress of the δ-phase of duplex stainless steel is rather sensitive to the chemical composition and annealing conditions, which is attributed to the size misfit parameter.

Study of Sigma Phase in Duplex SAF 2507

Science.gov (United States)

Fellicia, D. M.; Sutarsis; Kurniawan, B. A.; Wulanari, D.; Purniawan, A.; Wibisono, A. T.

2017-05-01

Super duplex stainless steel is one of the stainless steel which has a combination between high strength properties and excellent corrosion resistance. However, the resistance can decrease by precipitation of sigma phase which is formed at high temperature, for example after welding processes. A series of experiments has been performed to study the effect of solution annealing to existence of sigma phase on super duplex SAF 2507. Variations of solution-annealing temperatures were 1000 °C, 1065 °C and 1125 °C with holding time of 15 and 30 minutes for each temperature. Effect of solution annealing process was characterized by using XRD, SEM, and Optical Microscopy. The result showed precipitation of sigma phase completely dissolved at 1065 °C and 1125 °C because it reformed to austenite. After it was heated at 1065 °C, chromium carbide appeared in ferrite site and grain boundary. The amount of chromium carbide increased with the increasing of solution annealing temperature.

Some pitfalls in welding of duplex stainless steels Algumas armadilhas na soldagem de aços inoxidáveis duplex

Directory of Open Access Journals (Sweden)

Demian J. Kotecki

2010-12-01

Full Text Available Duplex stainless steels (DSS, including super duplex stainless steels {SDSS} have proven to be very useful engineering materials, albeit with somewhat different welding requirements than those of the more familiar austenitic stainless steels. Despite a generally good track record in welding of duplex stainless steels, certain pitfalls have been encountered with enough frequency that they deserve review. Inappropriate base metal specification often leads to unsuitable heat affected zone (HAZ properties. Autogenous fusion zones are also of concern. This issue centers around nitrogen limits. The most frequently encountered is applying the UNS S31803 composition for 2205 DSS, instead of the S32205 composition. Inappropriate welding heat input arises most frequently with SDSS. While 0.5 to 1.5 kJ/mm is a normal heat input recommendation for SDSS, either a root pass or many small beads towards the low end of this heat input range tends to result in precipitation and/or secondary austenite formation in weld metal subjected to repeated thermal cycles from multiple weld passes. Inappropriate PWHT occurs when the enhanced nickel filler metals (typically 9% Ni are used. DSS are not normally given PWHT, but extensive forming of heads, for example, or repair welding of castings, may require a postweld anneal. Specifications such as ASTM A790 and A890 call for annealing at 1040ºC minimum, and the fabricator tends to use temperatures close to that minimum. However, the enhanced nickel filler metals require higher temperatures to dissolve sigma phase that forms during heating to the annealing temperature.Aços inoxidáveis duplex (AID, incluindo os aços super duplex, AISD provaram ser materiais de engenharia muito úteis, embora com requerimentos de soldagem em alguma medida diferentes daqueles dos aços inoxidáveis austeníticos mais usuais. Apesar do histórico geralmente bom dos aços inoxidáveis duplex quanto a soldagem, algumas dificuldades têm sido

The effects of laser welding parameters on the microstructure of ferritic and duplex stainless steels welds

Science.gov (United States)

Pekkarinen, J.; Kujanpää, V.

This study is focused to determine empirically, which microstructural changes occur in ferritic and duplex stainless steels when heat input is controlled by welding parameters. Test welds were done autogenously bead-on-plate without shielding gas using 5 kW fiber laser. For comparison, some gas tungsten arc welds were made. Used test material were 1.4016 (AISI 430) and 1.4003 (low-carbon ferritic) type steels in ferritic steels group and 1.4162 (low-alloyed duplex, LDX2101) and 1.4462 (AISI 2205) type steels in duplex steels group. Microstructural changes in welds were identified and examined using optical metallographic methods.

Dilution and Ferrite Number Prediction in Pulsed Current Cladding of Super-Duplex Stainless Steel Using RSM

Science.gov (United States)

Eghlimi, Abbas; Shamanian, Morteza; Raeissi, Keyvan

2013-12-01

Super-duplex stainless steels have an excellent combination of mechanical properties and corrosion resistance at relatively low temperatures and can be used as a coating to improve the corrosion and wear resistance of low carbon and low alloy steels. Such coatings can be produced using weld cladding. In this study, pulsed current gas tungsten arc cladding process was utilized to deposit super-duplex stainless steel on high strength low alloy steel substrates. In such claddings, it is essential to understand how the dilution affects the composition and ferrite number of super-duplex stainless steel layer in order to be able to estimate its corrosion resistance and mechanical properties. In the current study, the effect of pulsed current gas tungsten arc cladding process parameters on the dilution and ferrite number of super-duplex stainless steel clad layer was investigated by applying response surface methodology. The validity of the proposed models was investigated by using quadratic regression models and analysis of variance. The results showed an inverse relationship between dilution and ferrite number. They also showed that increasing the heat input decreases the ferrite number. The proposed mathematical models are useful for predicting and controlling the ferrite number within an acceptable range for super-duplex stainless steel cladding.

The design and analysis of AVTMR (all voting triple modular redundancy) and dual-duplex system

International Nuclear Information System (INIS)

Kim, Hyunki; Lee, Hyeuntae; Lee, Keyseo

2005-01-01

In this paper, we design AVTMR (All Voting Triple Modular Redundancy) and dual-duplex system which have a fault-tolerant characteristic, and two systems are compared in the evaluation of RAMS (Reliability, Availability, Maintainability and Safety) and MTTF (Mean Time To Failure). AVTMR system is designed in a triplicated voter technique and dual-duplex system in a comparator, and two systems are based on MC68000. To evaluate system characteristic, Markov modeling method is designed for reliability, availability, safety and MTTF (Mean Time To Failure), and RELEX6.0 tool is used for the calculation of failure rate of electrical components that is based on MILSPEC-217F. In this paper, we can see two systems are more high dependability than a single system, and AVTMR or dual-duplex system can be selected for a specific application system. Especially, because AVTMR and dual-duplex system have high RAMS better than a single system, they can be applied to life critical system such as an airplane and a high-speed railway system

Estimation of brachial artery volume flow by duplex ultrasound imaging predicts dialysis access maturation.

Science.gov (United States)

Ko, Sae Hee; Bandyk, Dennis F; Hodgkiss-Harlow, Kelley D; Barleben, Andrew; Lane, John

2015-06-01

This study validated duplex ultrasound measurement of brachial artery volume flow (VF) as predictor of dialysis access flow maturation and successful hemodialysis. Duplex ultrasound was used to image upper extremity dialysis access anatomy and estimate access VF within 1 to 2 weeks of the procedure. Correlation of brachial artery VF with dialysis access conduit VF was performed using a standardized duplex testing protocol in 75 patients. The hemodynamic data were used to develop brachial artery flow velocity criteria (peak systolic velocity and end-diastolic velocity) predictive of three VF categories: low (800 mL/min). Brachial artery VF was then measured in 148 patients after a primary (n = 86) or revised (n = 62) upper extremity dialysis access procedure, and the VF category correlated with access maturation or need for revision before hemodialysis usage. Access maturation was conferred when brachial artery VF was >600 mL/min and conduit imaging indicated successful cannulation based on anatomic criteria of conduit diameter >5 mm and skin depth 800 mL/min was predicted when the brachial artery lumen diameter was >4.5 mm, peak systolic velocity was >150 cm/s, and the diastolic-to-systolic velocity ratio was >0.4. Brachial artery velocity spectra indicating VF 800 mL/min. Duplex testing to estimate brachial artery VF and assess the conduit for ease of cannulation can be performed in 5 minutes during the initial postoperative vascular clinic evaluation. Estimation of brachial artery VF using the duplex ultrasound, termed the "Fast, 5-min Dialysis Duplex Scan," facilitates patient evaluation after new or revised upper extremity dialysis access procedures. Brachial artery VF correlates with access VF measurements and has the advantage of being easier to perform and applicable for forearm and also arm dialysis access. When brachial artery velocity spectra criteria confirm a VF >800 mL/min, flow maturation and successful hemodialysis are predicted if anatomic criteria

Throughput maximization for buffer-aided hybrid half-/full-duplex relaying with self-interference

KAUST Repository

Khafagy, Mohammad Galal

2015-06-01

In this work, we consider a two-hop cooperative setting where a source communicates with a destination through an intermediate relay node with a buffer. Unlike the existing body of work on buffer-aided half-duplex relaying, we consider a hybrid half-/full-duplex relaying scenario with loopback interference in the full-duplex mode. Depending on the channel outage and buffer states that are assumed available at the transmitters, the source and relay may either transmit simultaneously or revert to orthogonal transmission. Specifically, a joint source/relay scheduling and relaying mode selection mechanism is proposed to maximize the end-to-end throughput. The throughput maximization problem is converted to a linear program where the exact global optimal solution is efficiently obtained via standard convex/linear numerical optimization tools. Finally, the theoretical findings are corroborated with event-based simulations to provide the necessary performance validation.

Importance of diastolic velocities in the detection of celiac and mesenteric artery disease by duplex ultrasound

DEFF Research Database (Denmark)

Perko, M J; Just, S; Schroeder, T V

1997-01-01

To assess the predictive value of ultrasound duplex scanning in the detection of superior mesenteric artery (SMA) and celiac artery (CA) occlusive disease.......To assess the predictive value of ultrasound duplex scanning in the detection of superior mesenteric artery (SMA) and celiac artery (CA) occlusive disease....

Alternate transmission relaying based on interference alignment in 3-relay half-duplex MIMO systems

KAUST Repository

Park, Seongho; Park, Kihong; Ko, Youngchai; Alouini, Mohamed-Slim

2012-01-01

In a half-duplex relaying, the capacity pre-log factor 1/2 is a major drawback in spectral efficiency. This paper proposes a linear precoding/decoding scheme and an alternate relaying protocol in a dual-hop half-duplex system where three relays help the communication between the source and the destination. In our proposed scheme, we consider a phase incoherent method in relays in which the source alternately transmits message signals to the different relays. In addition, we propose a linear interference alignment scheme which can suppress the inter-relay interference resulting from the phase incoherence of relaying. Based on our analysis of degrees of freedom and our simulation results, we show that our proposed scheme achieves additional degrees of freedom compared to the conventional half-duplex relaying. © 2012 IEEE.

Alternate transmission relaying based on interference alignment in 3-relay half-duplex MIMO systems

KAUST Repository

Park, Seongho

2012-09-01

In a half-duplex relaying, the capacity pre-log factor 1/2 is a major drawback in spectral efficiency. This paper proposes a linear precoding/decoding scheme and an alternate relaying protocol in a dual-hop half-duplex system where three relays help the communication between the source and the destination. In our proposed scheme, we consider a phase incoherent method in relays in which the source alternately transmits message signals to the different relays. In addition, we propose a linear interference alignment scheme which can suppress the inter-relay interference resulting from the phase incoherence of relaying. Based on our analysis of degrees of freedom and our simulation results, we show that our proposed scheme achieves additional degrees of freedom compared to the conventional half-duplex relaying. © 2012 IEEE.

A full-duplex working integrated optoelectronic device for optical interconnect

Science.gov (United States)

Liu, Kai; Fan, Huize; Huang, Yongqing; Duan, Xiaofeng; Wang, Qi; Ren, Xiaomin; Wei, Qi; Cai, Shiwei

2018-05-01

In this paper, a full-duplex working integrated optoelectronic device is proposed. It is constructed by integrating a vertical cavity surface emitting laser (VCSEL) unit above a resonant cavity enhanced photodetector (RCE-PD) unit. Analysis shows that, the VCSEL unit has a threshold current of 1 mA and a slop efficiency of 0.66 W/A at 849.7 nm, the RCE-PD unit obtains its maximal absorption quantum efficiency of 90.24% at 811 nm with a FWHM of 4 nm. Moreover, the two units of the proposed integrated device can work independently from each other. So that the proposed integrated optoelectronic device can work full-duplex. It can be applied for single fiber bidirectional optical interconnects system.

Genetic relatedness of orbiviruses by RNA-RNA blot hybridization

International Nuclear Information System (INIS)

Bodkin, D.K.

1985-01-01

RNA-RNA blot hybridization was developed in order to identify type-specific genes among double-stranded (ds) RNA viruses, to assess the genetic relatedness of dsRNA viruses and to classify new strains. Viral dsRNA segments were electrophoresed through 10% polyacrylamide gels, transferred to membranes, and hybridized to [5' 32 P]-pCp labeled genomic RNA from a related strain. Hybridization was performed at 52 0 C, 50% formamide, 5X SSC. Under these conditions heterologous RNA species must share ≥ 74% sequence homology in order to form stable dsRNA hybrids. Cognate genes of nine members of the Palyam serogroup of orbiviruses were identified and their sequence relatedness to the prototype. Palyam virus, was determined. Reciprocal blot hybridizations were performed using radiolabeled genomic RNA of all members of the Palyam serogroup. Unique and variant genes were identified by lack of cross-homology or by weak homology between segments. Since genes 2 and 6 exhibited the highest degree of sequence variability, response to the vertebrate immune system may be a major cause of sequence divergence among members of a single serogroup. Changuinola serogroup isolates were compared by dot-blot hybridization, while Colorado tick fever (CTF) serogroup isolates were compared by the RNA-RNA blot hybridization procedure described for reovirus and Palyam serogroup isolates. Preliminary blot hybridization data were also obtained on the relatedness of members of different Orbivirus serogroups

Efficient Cooperative Protocols for Full-Duplex Relaying over Nakagami-m Fading Channels

KAUST Repository

Khafagy, Mohammad Galal

2015-02-24

In this work, efficient protocols are studied for full-duplex relaying (FDR) with loopback interference over Nakagami-m block fading channels. Recently, a selective decodeand- forward (DF) protocol was proposed for FDR, and was shown to outperform existing protocols in terms of outage over Rayleigh-fading channels. In this work, we propose an incremental selective DF protocol that offers additional power savings, yet yields the same outage performance. We evaluate their outage performance over independent non-identically distributed Nakagami-m fading links, and study their relative performance in terms of the signal-to-noise ratio cumulative distribution function via closed-form expressions. The offered diversity gain is also derived. In addition, we study their performance relative to their half-duplex counterparts, as well as known non-selective FDR protocols. We corroborate our theoretical results with simulation, and confirm that selective cooperation protocols outperform the known non-selective protocols in terms of outage. Finally, we show that depending on the loopback interference level, the proposed protocols can outperform their half-duplex counterparts when high spectral efficiencies are targeted.

Efficient Cooperative Protocols for Full-Duplex Relaying over Nakagami-m Fading Channels

KAUST Repository

Khafagy, Mohammad Galal; Tammam, Amr; Alouini, Mohamed-Slim; Aissa, Sonia

2015-01-01

In this work, efficient protocols are studied for full-duplex relaying (FDR) with loopback interference over Nakagami-m block fading channels. Recently, a selective decodeand- forward (DF) protocol was proposed for FDR, and was shown to outperform existing protocols in terms of outage over Rayleigh-fading channels. In this work, we propose an incremental selective DF protocol that offers additional power savings, yet yields the same outage performance. We evaluate their outage performance over independent non-identically distributed Nakagami-m fading links, and study their relative performance in terms of the signal-to-noise ratio cumulative distribution function via closed-form expressions. The offered diversity gain is also derived. In addition, we study their performance relative to their half-duplex counterparts, as well as known non-selective FDR protocols. We corroborate our theoretical results with simulation, and confirm that selective cooperation protocols outperform the known non-selective protocols in terms of outage. Finally, we show that depending on the loopback interference level, the proposed protocols can outperform their half-duplex counterparts when high spectral efficiencies are targeted.

Standard duplex criteria overestimate the degree of stenosis after eversion carotid endarterectomy.

Science.gov (United States)

Benzing, Travis; Wilhoit, Cameron; Wright, Sharee; McCann, P Aaron; Lessner, Susan; Brothers, Thomas E

2015-06-01

The eversion technique for carotid endarterectomy (eCEA) offers an alternative to longitudinal arteriotomy and patch closure (pCEA) for open carotid revascularization. In some reports, eCEA has been associated with a higher rate of >50% restenosis of the internal carotid when it is defined as peak systolic velocity (PSV) >125 cm/s by duplex imaging. Because the conformation of the carotid bifurcation may differ after eCEA compared with native carotid arteries, it was hypothesized that standard duplex criteria might not accurately reflect the presence of restenosis after eCEA. In a case-control study, the outcomes of all patients undergoing carotid endarterectomy by one surgeon during the last 10 years were analyzed retrospectively, with a primary end point of PSV >125 cm/s. Duplex flow velocities were compared with luminal diameter measurements for any carotid computed tomography arteriography or magnetic resonance angiography study obtained within 2 months of duplex imaging, with the degree of stenosis calculated by the methodology used in the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and the European Carotid Surgery Trial (ECST) as well as cross-sectional area (CSA) reduction. Simulations were generated and analyzed by computational model simulations of the eCEA and pCEA arteries. Eversion and longitudinal arteriotomy with patch techniques were used in 118 and 177 carotid arteries, respectively. Duplex follow-up was available in 90 eCEA arteries at a median of 16 (range, 2-136) months and in 150 pCEA arteries at a median of 41 (range, 3-115) months postoperatively. PSV >125 cm/s was present at some time during follow-up in 31% of eCEA and pCEA carotid arteries, each, and in the most recent duplex examination in 7% after eCEA and 21% after pCEA (P = .003), with no eCEA and two pCEA arteries occluding completely during follow-up (P = .29). In 19 carotid arteries with PSV >125 cm/s after angle correction (median, 160 cm/s; interquartile range

Role of magnetic resonance urography in diagnosis of duplex renal system: Our initial experience at a tertiary care institute

Directory of Open Access Journals (Sweden)

Milind P Joshi

2009-01-01

Full Text Available Aim: To determine diagnostic value of magnetic resonance urography in cases of duplex renal system. Method: Twenty cases between five month to nine years with suspected or known duplex renal system were evaluated by ultrasound (USG, micturating cystourethrography (MCU, intravenous urography (IVU and magnetic resonance urography (MRU. The findings of these diagnostic imaging studies were then compared with each other and against the results of final diagnosis established at surgery. Results: Duplex renal system could be identified in two of these cases on USG, was diagnosed in four in IVU and could be diagnosed in all cases with MRU. Conclusion: MRU is superior and far accurate than IVU, MCU and USG in diagnosing duplex renal system.

In-Band Full-Duplex Communications for Cellular Networks with Partial Uplink/Downlink Overlap

KAUST Repository

Alammouri, Ahmad; Elsawy, Hesham; Amin, Osama; Alouini, Mohamed-Slim

2015-01-01

In-band full-duplex (FD) communications have been optimistically promoted to improve the spectrum utilization in cellular networks. However, the explicit impact of spatial interference, imposed by FD communications, on uplink and downlink transmissions has been overlooked in the literature. This paper presents an extensive study of the explicit effect of FD communications on the uplink and downlink performances. For the sake of rigorous analysis, we develop a tractable framework based on stochastic geometry toolset. The developed model accounts for uplink truncated channel inversion power control in FD cellular networks. The study shows that FD communications improve the downlink throughput at the expense of significant degradation in the uplink throughput. Therefore, we propose a novel fine-grained duplexing scheme, denoted as α-duplex scheme, which allows a partial overlap between uplink and downlink frequency bands. To this end, we show that the amount of the overlap can be optimized via adjusting α to achieve a certain design objective.

In-Band Full-Duplex Communications for Cellular Networks with Partial Uplink/Downlink Overlap

KAUST Repository

AlAmmouri, Ahmad

2015-12-06

In-band full-duplex (FD) communications have been optimistically promoted to improve the spectrum utilization in cellular networks. However, the explicit impact of spatial interference, imposed by FD communications, on uplink and downlink transmissions has been overlooked in the literature. This paper presents an extensive study of the explicit effect of FD communications on the uplink and downlink performances. For the sake of rigorous analysis, we develop a tractable framework based on stochastic geometry toolset. The developed model accounts for uplink truncated channel inversion power control in FD cellular networks. The study shows that FD communications improve the downlink throughput at the expense of significant degradation in the uplink throughput. Therefore, we propose a novel fine-grained duplexing scheme, denoted as α-duplex scheme, which allows a partial overlap between uplink and downlink frequency bands. To this end, we show that the amount of the overlap can be optimized via adjusting α to achieve a certain design objective.

Microstructure and properties of duplex (Ti:N)-DLC/MAO coating on magnesium alloy

Energy Technology Data Exchange (ETDEWEB)

Yang, Wei; Ke, Peiling [Ningbo Key Laboratory of Marine Protection Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Fang, Yong [Sir Run Run Shaw Hospital, School of Medicine, Zhe Jiang University, Zhejiang 310016 (China); Zheng, He [Ningbo Key Laboratory of Marine Protection Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Wang, Aiying, E-mail: aywang@nimte.ac.cn [Ningbo Key Laboratory of Marine Protection Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China)

2013-04-01

Ti and N co-doped diamond-like carbon ((Ti:N)-DLC) film was deposited on the MAO coated substrate using a hybrid beam deposition system, which consists of a DC magnetron sputtering of Ti target and a linear ion source (LIS) with C{sub 2}H{sub 2} and N{sub 2} precursor gas. The microstructure and properties of the duplex (Ti:N)-DLC/MAO coating were investigated. Results indicate that the (Ti:N)-DLC top film with TiN crystalline phase was formed. Ti and N co-doping resulted in the increasing I{sub D}/I{sub G} ratio. The significant improvement in the wear and corrosion resistance of duplex (Ti:N)-DLC/MAO coating was mainly attributed to the increased binding strength, lubrication characteristics and chemical inertness of (Ti:N)-DLC top film. The superior low-friction and anti-corrosion properties of duplex (Ti:N)-DLC/MAO coating make it a good candidate as protective coating on magnesium alloy.

Duplex sonography and magnetic resonance imaging in the clarification of nephrological complications after renal transplant

International Nuclear Information System (INIS)

Gueckel, C.; Krestin, G.P.; Wienand, P.

1989-01-01

A prospective study compared Duplex sonography and magnetic resonance imaging in evaluating renal transplant. Hundred and two Duplex sonographic and 24 MR examinations were performed and correlated with clinical course or biopsy. All normal renal allografts, 6 transplants with acute tubular necrosis and 2 cases of cyclosporin toxicity had normal Doppler waveforms, whereas 9 renal transplants with evidence of interstitial rejection by biopsy showed an obliteration or reversal of diastolic flow. MR imaging was less specific in identifying allograft rejection. There were false positive results in normal renal transplants, allografts with acute tubular necrosis and after rejection therapy. With regard to cost, accessibility and specificity, Duplex sonography is the method of choice for the evaluation of renal allografts. (orig.) [de

Radiation sensitivity of messenger RNA

International Nuclear Information System (INIS)

Ponta, H.; Pfennig-Yeh, M.L.; Herrlich, P.; Karlsruhe Univ.; Wagner, E.F.; Schweiger, M.

1979-01-01

Messenger RNA function is inactivated by irradiation with ultraviolet light. A unit length mRNA (in bases) is 2-3 times more sensitive than a unit length of DNA (in base pairs) with respect to the inactivation of template function. These data stem from four experimental systems all of which do not repair DNA: the translation of E. coli mRNA in rifampicin-treated cells, of T7 mRNA in infected E.coli, of f2 phage RNA in vivo, and of stable mRNA in chromosomeless minicells. The comparison of relative sensitivities to UV is relevant to the technique of UV mapping of transcription units which enjoys increasing popularity in pro- and eukaryotic genetic research. (orig.) [de

Radiation sensitivity of messenger RNA

Energy Technology Data Exchange (ETDEWEB)

Ponta, H; Pfennig-Yeh, M L; Herrlich, P [Kernforschungszentrum Karlsruhe G.m.b.H. (Germany, F.R.). Inst. fuer Genetik und Toxikologie von Spaltstoffen; Karlsruhe Univ. (TH) (Germany, F.R.). Inst. fuer Genetik); Wagner, E F; Schweiger, M [Innsbruck Univ. (Austria). Inst. fuer Biochemie

1979-08-01

Messenger RNA function is inactivated by irradiation with ultraviolet light. A unit length mRNA (in bases) is 2-3 times more sensitive than a unit length of DNA (in base pairs) with respect to the inactivation of template function. These data stem from four experimental systems all of which do not repair DNA: the translation of E. coli mRNA in rifampicin-treated cells, of T7 mRNA in infected E.coli, of f2 phage RNA in vivo, and of stable mRNA in chromosomeless minicells. The comparison of relative sensitivities to UV is relevant to the technique of UV mapping of transcription units which enjoys increasing popularity in pro- and eukaryotic genetic research.

Reliability Capacity of Half-Duplex Channels with Strict Deadlines

DEFF Research Database (Denmark)

Costa, Rui; Roetter, Daniel Enrique Lucani; Vinhoza, Tiago

2015-01-01

A fundamental characterization of a half-duplex wireless system with packet losses under traffic with hard deadlines is instrumental to understanding and developing efficient, coding aware policies for real-time applications. We set forth the concept of reliability capacity with a limited number ...

Duplex sonography of the near-surface leg veins; Duplexsonographie der oberflaechlichen Beinvenen

Energy Technology Data Exchange (ETDEWEB)

Mendoza, E.

2007-07-01

The book contains the following contributions: The ultrasonograph, selection of the ultrasonic transducer, anatomy of the near-surface vein system, physiology of the near-surface vein system, varicose status classification, systematics of the duplex sonography of near-surface leg veins, provocational maneuver for the duplex sonographic varicose diagnostics, exploration of vena saphena parva, perforans veins, side branches, phlebitis, sonography for varicose therapy, postsurgical sonography, deep leg veins, examination of near-surface leg veins for the pathology of the deep vein system, differential diagnostic clarification of leg oedema from the phlebologic-lymphological view, diagnostic side features along the near-surface leg veins.

Characterization of Duplex steel Uranus 76N during deformation and heat treatment

Energy Technology Data Exchange (ETDEWEB)

Lecomte-Beckers, J.; Carton, M. [ASMA Department - Sector, Special Metallic Materials, University of Liege, Chemin des Chevreuils 1, 4000 Liege 1 (Belgium); Moureaux, P.; Habraken, A.M. [M and S Department - Sector, Mechanic of Solids and Material, University of Liege, Chemin des Chevreuils 1, 4000 Liege 1 (Belgium)

2006-12-15

Duplex Uranus 76N is characterized by metallography, thermal and mechanical analysis. The investigation shows that the microstructure of such a Duplex strongly depends on the cooling conditions determining the quantity of austenite formed in the ferrite matrix. Numerical simulations of 76N behavior during the rolling process and service life require the knowledge of the recrystallization state during rolling steps at high temperature, thermal parameters such as dilatation, density, specific heat, thermal diffusivity, thermal conductivity and mechanical constitutive laws. These material parameters are determined and presented in this study. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

The value of pre-discharge Duplex scanning in infrainguinal graft surveillance.

Science.gov (United States)

Wilson, Y G; Davies, A H; Currie, I C; McGrath, C; Morgan, M; Baird, R N; Lamont, P M

1995-08-01

Protocols and criteria for Duplex-based graft surveillance programmes (GS) vary widely as to the optimum regimens for maximising detection of "at risk" grafts. Few centres recommend starting GS before discharge. The aim of this study was to audit our experience with respect to early scanning. Vascular Studies Unit, Bristol Royal Infirmary. The records of 123 patients entering GS from January 1992 were reviewed. Patients were scanned at 1 week, 6 weeks and 3, 6, 9 and 12 months post-bypass. Haemodynamic criteria used were a peak mean velocity (PMV) less than 45 cm/s and a focal velocity disturbance with a V2/V1 ratio of 1.5 or more. Forty-six abnormalities (37% detection rate) were identified on scans within one week. In all cases, on-table completion studies with either arteriography and/or flow measurements had failed to identify the anomalies subsequently detected by Duplex. At 1 week, six grafts had occluded, 27 had a focal PMV increase (mean V2/V1 ratio: 2.6; range 1.5-4.3), four had low flow velocities, four had arteriovenous fistulae, one contained mobile thrombus, two had retained cusps and two had hamstring entrapment. Of 40 patent, but compromised grafts, 18 warranted immediate investigation. Of the 27 patients with velocity disturbances on Duplex, 25 were simply observed but, eight have since required intervention for definitive stenoses at these sites which, in retrospect, were evident within the first postoperative week. Pre-discharge scanning is a useful modality for detecting technical problems. Intrinsic graft abnormalities, possibly the sites of future definitive stenoses, have been visualised even at 1 week and once identified, can be more closely scrutinised thereafter. Pre-discharge colour Duplex is recommended as standard practice for quality control after infrainguinal bypass.

99Tcm-DTPA renography in evaluating the function of duplex kidneys in pediatric patients

International Nuclear Information System (INIS)

Zhang Lixia; Wang Xiaoming; Chen Jinyan; Su Junmei

2013-01-01

Objective: To study the value of 99 Tc m -DTPA dynamic renography in evaluating the function of duplex kidneys in pediatric patients. Methods: Twenty-five pediatric patients with duplex kidneys diagnosed by ultrasound or MR urography (MRU) were included (9 males, 16 females; mean age:(23.80 ± 20.97) months, range: 2-72 months). Twenty patients (9 males,11 females; mean age: (32.95 ± 23.58) months, range: 2-72 months) with urinary tract infection but without duplex kidneys confirmed by ultrasound or MRU were chosen as control group during the same period of this study. All patients and controls were divided into two subgroups according to their ages (group Ⅰ, 0-24 months; group Ⅱ, 25-72 months). The research was approved by the ethics committee, and all patients' parents (or guardians) signed informed consents. The time-activity curve was generated on the dynamic imaging data automatically with GFR calculated. The uptake rates of the upper and lower moieties were measured by drawing the corresponding ROIs in the duplex kidney. Dunnett-t test was used for statistical analysis. Results: There were 25 patients with 26 duplex kidneys (1 case bilateral), 16 on the left and 10 on the right. The time-activity curve of 6 cases was normal, 9 with continuously upward type, 4 with high level plateau type, 2 with parabolic type and 5 with low level plateau type. There were 19 abnormal kidneys in group Ⅰ and 7 in group Ⅱ, and 20 kidneys in each control subgroup. The GFR of patients with normal renography was (78.81 ± 15.97) ml/min (group Ⅰ) and (64.68 ± 11.15) ml/min (group Ⅱ), continuously upward type was (72.11 ±22.76) ml/min (group Ⅰ) and (63.41 ± 16.42) ml/min (group Ⅱ), high level plateau and parabolic types were (68.74 ± 16.17) ml/min and (65.26 ± 15.27) ml/min in group Ⅰ, respectively. There was no statistically significant difference between the GFR of different renography type groups and that of the controls (group Ⅰ: (79.35 ±13.31) ml

A Commentary on "Updating the Duplex Design for Test-Based Accountability in the Twenty-First Century"

Science.gov (United States)

Brandt, Steffen

2010-01-01

This article presents the author's commentary on "Updating the Duplex Design for Test-Based Accountability in the Twenty-First Century," in which Isaac I. Bejar and E. Aurora Graf propose the application of a test design--the duplex design (which was proposed in 1988 by Bock and Mislevy) for application in current accountability assessments.…

Revealing stable processing products from ribosome-associated small RNAs by deep-sequencing data analysis.

Science.gov (United States)

Zywicki, Marek; Bakowska-Zywicka, Kamilla; Polacek, Norbert

2012-05-01

The exploration of the non-protein-coding RNA (ncRNA) transcriptome is currently focused on profiling of microRNA expression and detection of novel ncRNA transcription units. However, recent studies suggest that RNA processing can be a multi-layer process leading to the generation of ncRNAs of diverse functions from a single primary transcript. Up to date no methodology has been presented to distinguish stable functional RNA species from rapidly degraded side products of nucleases. Thus the correct assessment of widespread RNA processing events is one of the major obstacles in transcriptome research. Here, we present a novel automated computational pipeline, named APART, providing a complete workflow for the reliable detection of RNA processing products from next-generation-sequencing data. The major features include efficient handling of non-unique reads, detection of novel stable ncRNA transcripts and processing products and annotation of known transcripts based on multiple sources of information. To disclose the potential of APART, we have analyzed a cDNA library derived from small ribosome-associated RNAs in Saccharomyces cerevisiae. By employing the APART pipeline, we were able to detect and confirm by independent experimental methods multiple novel stable RNA molecules differentially processed from well known ncRNAs, like rRNAs, tRNAs or snoRNAs, in a stress-dependent manner.

Three-dimensional shuffling of horses in a strike-slip duplex: an example from the Lambertville sill, New Jersey

Science.gov (United States)

Laney, Stephen E.; Gates, Alexander E.

1996-06-01

Detailed analysis of a dextral strike-slip duplex within the relatively isotropic rocks of the Lambertville sill, New Jersey indicates that horses have experienced vertical, horizontal and oblique movements resulting from extrusional shuffling within a restraining bend. This is the first documentation of the three-dimensional movement of horses within a strike-slip duplex. Deformation within the duplex shows a complex system of early synthetic fractures and reverse faults followed by antithetic fractures which dissect previously continuous slab-shaped horses into diamond-shaped lenses. Most faults are oblique slip. Antithetic fault movements and clockwise rigid rotation of horses dominate the south half of the duplex and synthetic movements and counterclockwise rotations dominate the north half. Slickenline plunges on curved horse-bounding fault surfaces within the duplex range from nearly horizontal to 40° resulting in both lateral movements (middle) to normal movements (tails) on a single horse. Curved slickensides commonly have opposite senses of movement on either side of individual horses indicating relative emergence or submergence. Such a geometry could also result from a group of horses moving in the same oblique direction but at different rates. These complex extrusional-type movements were observed in both cross-sectional and plan views. The net result of the movements is a contraction or flattening of the duplex normal to the bounding faults. The horses shifted to accommodate this flattening as overall displacement was transferred between the bounding faults along curved internal faults.

NMR and molecular modeling evidence for a G·A mismatch base pair in a purine-rich DNA duplex

International Nuclear Information System (INIS)

Li, Ying; Wilson, W.D.; Zon, G.

1991-01-01

1 H NMR experiments indicate that the oligomer 5'-d(ATGAGCGAATA) forms an unusual 10-base-pair duplex with 4 G·A base pairs and a 3' unpaired adenosine. NMR results indicate that guanoxine imino protons of the F·A mismatches are not hydrogen bonded but are stacked in the helix. A G→ I substitution in either G·A base pair causes a dramatic decrtease in duplex stability and indicates that hydrogen bonding of the guanosine amino group is critical. Nuclear Overhauser effect spectroscopy (NOESY) and two-dimensional correlated spectroscopy (COSY) results indicate that the overall duplex conformation is in the B-family. Cross-strand NOEs in two-dimensional NOESY spectra between a mismatched AH2 and an AH1' of the other mismatched base pair and between a mismatched GH8 and GNH1 of the other mismatch establish a purine-purine stacking pattern, adenosine over adenosine and guanosine over guanosine, which strongly stabilizes the duplex. A computer graphics molecular model of the ususual duplex was constructed with G·A base pairs containing A-NH 2 to GN3 and G-NH 2 to AN7 hydrogen bonds and B-form base pairs on both sides of the G·A pairs [5'-d(ATGAGC)]. The energy-minimized duplex satisfies all experimental constraints from NOESY and COSY results. A hydrogen bond from G-NH 2 of the mismatch to a phosphate oxygen is predicted

Block compressed sensing for feedback reduction in relay-aided multiuser full duplex networks

KAUST Repository

Elkhalil, Khalil

2016-08-11

Opportunistic user selection is a simple technique that exploits the spatial diversity in multiuser relay-aided networks. Nonetheless, channel state information (CSI) from all users (and cooperating relays) is generally required at a central node in order to make selection decisions. Practically, CSI acquisition generates a great deal of feedback overhead that could result in significant transmission delays. In addition to this, the presence of a full-duplex cooperating relay corrupts the fed back CSI by additive noise and the relay\\'s loop (or self) interference. This could lead to transmission outages if user selection is based on inaccurate feedback information. In this paper, we propose an opportunistic full-duplex feedback algorithm that tackles the above challenges. We cast the problem of joint user signal-to-noise ratio (SNR) and the relay loop interference estimation at the base-station as a block sparse signal recovery problem in compressive sensing (CS). Using existing CS block recovery algorithms, the identity of the strong users is obtained and their corresponding SNRs are estimated. Numerical results show that the proposed technique drastically reduces the feedback overhead and achieves a rate close to that obtained by techniques that require dedicated error-free feedback from all users. Numerical results also show that there is a trade-off between the feedback interference and load, and for short coherence intervals, full-duplex feedback achieves higher throughput when compared to interference-free (half-duplex) feedback. © 2016 IEEE.

Block compressed sensing for feedback reduction in relay-aided multiuser full duplex networks

KAUST Repository

Elkhalil, Khalil; Eltayeb, Mohammed; Kammoun, Abla; Al-Naffouri, Tareq Y.; Bahrami, Hamid Reza

2016-01-01

Opportunistic user selection is a simple technique that exploits the spatial diversity in multiuser relay-aided networks. Nonetheless, channel state information (CSI) from all users (and cooperating relays) is generally required at a central node in order to make selection decisions. Practically, CSI acquisition generates a great deal of feedback overhead that could result in significant transmission delays. In addition to this, the presence of a full-duplex cooperating relay corrupts the fed back CSI by additive noise and the relay's loop (or self) interference. This could lead to transmission outages if user selection is based on inaccurate feedback information. In this paper, we propose an opportunistic full-duplex feedback algorithm that tackles the above challenges. We cast the problem of joint user signal-to-noise ratio (SNR) and the relay loop interference estimation at the base-station as a block sparse signal recovery problem in compressive sensing (CS). Using existing CS block recovery algorithms, the identity of the strong users is obtained and their corresponding SNRs are estimated. Numerical results show that the proposed technique drastically reduces the feedback overhead and achieves a rate close to that obtained by techniques that require dedicated error-free feedback from all users. Numerical results also show that there is a trade-off between the feedback interference and load, and for short coherence intervals, full-duplex feedback achieves higher throughput when compared to interference-free (half-duplex) feedback. © 2016 IEEE.

Half-Duplex and Full-Duplex AF and DF Relaying with Energy-Harvesting in Log-Normal Fading

KAUST Repository

Rabie, Khaled M.

2017-08-15

Energy-harvesting (EH) and wireless power transfer in cooperative relaying networks have recently attracted a considerable amount of research attention. Most of the existing work on this topic however focuses on Rayleigh fading channels, which represent outdoor environments. In contrast, this paper is dedicated to analyze the performance of dual-hop relaying systems with EH over indoor channels characterized by log-normal fading. Both half-duplex (HD) and full-duplex (FD) relaying mechanisms are studied in this work with decode-and-forward (DF) and amplify-and-forward (AF) relaying protocols. In addition, three EH schemes are investigated, namely, time switching relaying, power splitting relaying and ideal relaying receiver which serves as a lower bound. The system performance is evaluated in terms of the ergodic outage probability for which we derive accurate analytical expressions. Monte Carlo simulations are provided throughout to validate the accuracy of our analysis. Results reveal that, in both HD and FD scenarios, AF relaying performs only slightly worse than DF relaying which can make the former a more efficient solution when the processing energy cost at the DF relay is taken into account. It is also shown that FD relaying systems can generally outperform HD relaying schemes as long as the loop-back interference in FD is relatively small. Furthermore, increasing the variance of the log-normal channel has shown to deteriorate the performance in all the relaying and EH protocols considered.

Counterpart synchronization of duplex networks with delayed nodes and noise perturbation

International Nuclear Information System (INIS)

Wei, Xiang; Wu, Xiaoqun; Lu, Jun-an; Zhao, Junchan

2015-01-01

In the real world, many complex systems are represented not by single networks but rather by sets of interdependent ones. In these specific networks, nodes in one network mutually interact with nodes in other networks. This paper focuses on a simple representative case of two-layer networks (the so-called duplex networks) with unidirectional inter-layer couplings. That is, each node in one network depends on a counterpart in the other network. Accordingly, the former network is called the response layer and the latter network is the drive layer. Specifically, synchronization between each node in the drive layer and its counterpart in the response layer (counterpart synchronization (CS)) in these kinds of duplex networks with delayed nodes and noise perturbation is investigated. Based on the LaSalle-type invariance principle, a control technique is proposed and a sufficient condition is developed for realizing CS of duplex networks. Furthermore, two corollaries are derived as special cases. In addition, node dynamics within each layer can be varied and topologies of the two layers are not necessarily identical. Therefore, the proposed synchronization method can be applied to a wide range of multiplex networks. Numerical examples are provided to illustrate the feasibility and effectiveness of the results. (paper)

X-Ray diffraction technique applied to study of residual stresses after welding of duplex stainless steel plates

International Nuclear Information System (INIS)

Monin, Vladimir Ivanovitch; Assis, Joaquim Teixeira de; Lopes, Ricardo Tadeu; Turibus, Sergio Noleto; Payao Filho, Joao C.

2014-01-01

Duplex stainless steel is an example of composite material with approximately equal amounts of austenite and ferrite phases. Difference of physical and mechanical properties of component is additional factor that contributes appearance of residual stresses after welding of duplex steel plates. Measurements of stress distributions in weld region were made by X-ray diffraction method both in ferrite and austenite phases. Duplex Steel plates were joined by GTAW (Gas Tungsten Arc Welding) technology. There were studied longitudinal and transverse stress components in welded butt joint, in heat affected zone (HAZ) and in points of base metal 10 mm from the weld. Residual stresses measured in duplex steel plates jointed by welding are caused by temperature gradients between weld zone and base metal and by difference of thermal expansion coefficients of ferrite and austenite phases. Proposed analytical model allows evaluating of residual stress distribution over the cross section in the weld region. (author)

Detection of 12 respiratory viruses by duplex real time PCR assays in respiratory samples.

Science.gov (United States)

Arvia, Rosaria; Corcioli, Fabiana; Ciccone, Nunziata; Della Malva, Nunzia; Azzi, Alberta

2015-12-01

Different viruses can be responsible for similar clinical manifestations of respiratory infections. Thus, the etiological diagnosis of respiratory viral diseases requires the detection of a large number of viruses. In this study, 6 duplex real-time PCR assays, using EvaGreen intercalating dye, were developed to detect 12 major viruses responsible for respiratory diseases: influenza A and B viruses, enteroviruses (including enterovirus spp, and rhinovirus spp), respiratory syncytial virus, human metapneumovirus, coronaviruses group I (of which CoV 229E and CoV NL63 are part) and II (including CoV OC43 and CoV HKU1), parainfluenza viruses type 1, 2, 3 and 4, human adenoviruses and human bocaviruses. The 2 target viruses of each duplex reaction were distinguishable by the melting temperatures of their amplicons. The 6 duplex real time PCR assays were applied for diagnostic purpose on 202 respiratory samples from 157 patients. One hundred fifty-seven samples were throat swabs and 45 were bronchoalveolar lavages. The results of the duplex PCR assays were confirmed by comparison with a commercial, validated, assay; in addition, the positive results were confirmed by sequencing. The analytical sensitivity of the duplex PCR assays varied from 10(3) copies/ml to 10(4) copies/ml. For parainfluenza virus 2 only it was 10(5) copies/ml. Seventy clinical samples (35%) from 55 patients (30 children and 25 adults) were positive for 1 or more viruses. In adult patients, influenza A virus was the most frequently detected respiratory virus followed by rhinoviruses. In contrast, respiratory syncytial virus was the most common virus in children, followed by enteroviruses, influenza A virus and coronavirus NL63. The small number of samples/patients does not allow us to draw any epidemiological conclusion. Altogether, the results of this study indicate that the 6 duplex PCR assays described in this study are sensitive, specific and cost-effective. Thus, this assay could be

Rapid detection of Opisthorchis viverrini and Strongyloides stercoralis in human fecal samples using a duplex real-time PCR and melting curve analysis.

Science.gov (United States)

Janwan, Penchom; Intapan, Pewpan M; Thanchomnang, Tongjit; Lulitanond, Viraphong; Anamnart, Witthaya; Maleewong, Wanchai

2011-12-01

Human opisthorchiasis caused by the liver fluke Opisthorchis viverrini is an endemic disease in Southeast Asian countries including the Lao People's Democratic Republic, Cambodia, Vietnam, and Thailand. Infection with the soil-transmitted roundworm Strongyloides stercoralis is an important problem worldwide. In some areas, both parasitic infections are reported as co-infections. A duplex real-time fluorescence resonance energy transfer (FRET) PCR merged with melting curve analysis was developed for the rapid detection of O. viverrini and S. stercoralis in human fecal samples. Duplex real-time FRET PCR is based on fluorescence melting curve analysis of a hybrid of amplicons generated from two genera of DNA elements: the 162 bp pOV-A6 DNA sequence specific to O. viverrini and the 244 bp 18S rRNA sequence specific to S. stercoralis, and two pairs of specific fluorophore-labeled probes. Both O. viverrini and S. stercoralis can be differentially detected in infected human fecal samples by this process through their different fluorescence channels and melting temperatures. Detection limit of the method was as little as two O. viverrini eggs and four S. stercoralis larvae in 100 mg of fecal sample. The assay could distinguish the DNA of both parasites from the DNA of negative fecal samples and fecal samples with other parasite materials, as well as from the DNA of human leukocytes and other control parasites. The technique showed 100% sensitivity and specificity. The introduced duplex real-time FRET PCR can reduce labor time and reagent costs and is not prone to carry over contamination. The method is important for simultaneous detection especially in areas where both parasites overlap incidence and is useful as the screening tool in the returning travelers and immigrants to industrialized countries where number of samples in the diagnostic units will become increasing.

There is no benefit to universal carotid artery duplex screening before a major cardiac surgical procedure.

Science.gov (United States)

Adams, Brian C; Clark, Ross M; Paap, Christina; Goff, James M

2014-01-01

Perioperative stroke is a devastating complication after cardiac surgery. In an attempt to minimize this complication, many cardiac surgeons routinely preoperatively order carotid artery duplex scans to assess for significant carotid stenosis. We hypothesize that the routine screening of preoperative cardiac surgery patients with carotid artery duplex scans detects few patients who would benefit from carotid intervention or that a significant carotid stenosis reliably predicts stroke risk after cardiac surgery. A retrospective review identified 1,499 patients who underwent cardiac surgical procedures between July 1999 and September 2010. Data collected included patient demographics, comorbidities, history of previous stroke, preoperative carotid artery duplex scan results, location of postoperative stroke, and details of carotid endarterectomy (CEA) procedures before, in conjunction with, or after cardiac surgery. Statistical methods included univariate analysis and Fisher's exact test. Twenty-six perioperative strokes were identified (1.7%). In the 21 postoperative stroke patients for whom there is complete carotid artery duplex scan data, 3 patients had a hemodynamically significant lesion (>70%) and 1 patient underwent unilateral carotid CEA for bilateral disease. Postoperative strokes occurred in the anterior cerebral circulation (69.2%), posterior cerebral circulation (15.4%), or both (15.4%). Patient comorbidities, preoperative carotid artery duplex scan screening velocities, or types of cardiac surgical procedure were not predictive for stroke. Thirteen patients (0.86%) underwent CEA before, in conjunction with, or after cardiac surgery. Two of these patients had symptomatic disease, 1 of whom underwent CEA before and the other after his cardiac surgery. Of the 11 asymptomatic patients, 2 underwent CEA before, 3 concurrently, and 6 after cardiac surgery. Left main disease (≥50% stenosis), previous stroke, and peripheral vascular disease were found to be

miREE: miRNA recognition elements ensemble

Science.gov (United States)

2011-01-01

Background Computational methods for microRNA target prediction are a fundamental step to understand the miRNA role in gene regulation, a key process in molecular biology. In this paper we present miREE, a novel microRNA target prediction tool. miREE is an ensemble of two parts entailing complementary but integrated roles in the prediction. The Ab-Initio module leverages upon a genetic algorithmic approach to generate a set of candidate sites on the basis of their microRNA-mRNA duplex stability properties. Then, a Support Vector Machine (SVM) learning module evaluates the impact of microRNA recognition elements on the target gene. As a result the prediction takes into account information regarding both miRNA-target structural stability and accessibility. Results The proposed method significantly improves the state-of-the-art prediction tools in terms of accuracy with a better balance between specificity and sensitivity, as demonstrated by the experiments conducted on several large datasets across different species. miREE achieves this result by tackling two of the main challenges of current prediction tools: (1) The reduced number of false positives for the Ab-Initio part thanks to the integration of a machine learning module (2) the specificity of the machine learning part, obtained through an innovative technique for rich and representative negative records generation. The validation was conducted on experimental datasets where the miRNA:mRNA interactions had been obtained through (1) direct validation where even the binding site is provided, or through (2) indirect validation, based on gene expression variations obtained from high-throughput experiments where the specific interaction is not validated in detail and consequently the specific binding site is not provided. Conclusions The coupling of two parts: a sensitive Ab-Initio module and a selective machine learning part capable of recognizing the false positives, leads to an improved balance between

Heat treatment temperature influence on ASTM A890 GR 6A super duplex stainless steel microstructure

International Nuclear Information System (INIS)

Martins, Marcelo; Casteletti, Luiz Carlos

2005-01-01

Duplex and super duplex stainless steels are ferrous alloys with up to 26% chromium, 8% nickel, 5% molybdenum and 0.3% nitrogen, which are largely used in applications in media containing ions from the halogen family, mainly the chloride ion (Cl - ). The emergence of this material aimed at substituting Copper-Nickel alloys (Cupro-Nickel) that despite presenting good corrosion resistance, has mechanical properties quite inferior to steel properties. The metallurgy of duplex and super duplex stainless steel is complex due to high sensitiveness to sigma phase precipitation that becomes apparent, due to the temperatures they are exposed on cooling from solidification as well as from heat treatment processes. The objective of this study was to verify the influence of heat treating temperatures on the microstructure and hardness of ASTM A890/A890M Gr 6A super duplex stainless steel type. Microstructure control is of extreme importance for castings, as the chemical composition and cooling during solidification inevitably provide conditions for precipitation of sigma phase. Higher hardness in these materials is directly associated to high sigma phase concentration in the microstructure, precipitated in the ferrite/austenite interface. While heat treatment temperature during solution treatment increases, the sigma phase content in the microstructure decreases and consequently, the material hardness diminishes. When the sigma phase was completely dissolved by the heat treatment, the material hardness was influenced only due to ferrite and austenite contents in the microstructure

Tribological behavior of duplex coating improved by ion implantation

International Nuclear Information System (INIS)

Kakas, D.; Skoric, B.; Rakita, M.

2004-01-01

In the present paper the tribological behavior of the coatings are discussed. Duplex coatings were applied on cold working steel 100Cr6. Samples were plasma nitrided at different thickness of plasma surface layers. TiN was deposited with a classic BALZERS PVD equipment and subsequent ion implantation. Ion implantation was provided with N 5+ ions. The other samples were produced with IBAD technology in DANFYSIK chamber. Wear resistance and exchanges of friction coefficient were measured with on-line test using special designed tribology equipment. Following the tests, the wear zone morphology and characteristics of surface layer structure as well as important properties were investigated by scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). Scratch adhesion testing was performed using commercially available equipment. Energy dispersive X-ray analysis (EDAX) of the wear-scars on pins provided essential information on the wear characteristics. In this paper some results related to influence of duplex coating production methodology on tribological behavior for cold working steel was presented

Uncomplicated duplex kidney and DMSA scintigraphy in children with urinary tract infection

International Nuclear Information System (INIS)

Stokland, Eira; Jodal, Ulf; Swerkersson, Svante; Hansson, Sverker; Sixt, Rune

2007-01-01

Renal duplication is the most common malformation of the urinary tract and is frequently seen among children with urinary tract infection (UTI). To evaluate problems in the interpretation of dimercaptosuccinic acid (DMSA) scintigraphy and to establish the range of relative function in uncomplicated unilateral duplication. Retrospective analysis of 303 children less than 2 years of age with first time non-obstructive urinary tract infection investigated by both urography and DMSA scintigraphy. At DMSA scintigraphy, renal lesions and/or relative function below 45% was considered abnormal. Urography was used as reference for the diagnosis of duplication. Duplex kidneys were found in 22 of 303 patients (7%). Of the 16 children with unilateral duplication, 10 had bilaterally undamaged kidneys with a range of relative function varying between 51% and 57% in the duplex kidney. In two of the children with unilateral duplication the imaging results were discordant. There was risk of underdiagnosis as well as overdiagnosis of renal damage at scintigraphy. Although it is important to be aware of this risk, the rate of misinterpretation was low. A range of 51% to 57% can be used as the limit for normality of the relative function of a unilateral duplex kidney. (orig.)

Uncomplicated duplex kidney and DMSA scintigraphy in children with urinary tract infection

Energy Technology Data Exchange (ETDEWEB)

Stokland, Eira [The Sahlgrenska Academy at Goeteborg University, Department of Paediatric Radiology, Goeteborg (Sweden); The Queen Silvia Children' s Hospital, Department of Paediatric Radiology, Goeteborg (Sweden); Jodal, Ulf; Swerkersson, Svante; Hansson, Sverker [The Sahlgrenska Academy at Goeteborg University, Department of Paediatrics, Goeteborg (Sweden); Sixt, Rune [The Sahlgrenska Academy at Goeteborg University, Department of Paediatric Clinical Physiology, Goeteborg (Sweden)

2007-08-15

Renal duplication is the most common malformation of the urinary tract and is frequently seen among children with urinary tract infection (UTI). To evaluate problems in the interpretation of dimercaptosuccinic acid (DMSA) scintigraphy and to establish the range of relative function in uncomplicated unilateral duplication. Retrospective analysis of 303 children less than 2 years of age with first time non-obstructive urinary tract infection investigated by both urography and DMSA scintigraphy. At DMSA scintigraphy, renal lesions and/or relative function below 45% was considered abnormal. Urography was used as reference for the diagnosis of duplication. Duplex kidneys were found in 22 of 303 patients (7%). Of the 16 children with unilateral duplication, 10 had bilaterally undamaged kidneys with a range of relative function varying between 51% and 57% in the duplex kidney. In two of the children with unilateral duplication the imaging results were discordant. There was risk of underdiagnosis as well as overdiagnosis of renal damage at scintigraphy. Although it is important to be aware of this risk, the rate of misinterpretation was low. A range of 51% to 57% can be used as the limit for normality of the relative function of a unilateral duplex kidney. (orig.)

Effect of welding processes on corrosion resistance of UNS S31803 duplex stainless steel

International Nuclear Information System (INIS)

Chiu, Liu Ho; Hsieh, Wen Chin

2003-01-01

An attractive combination of corrosion resistance and mechanical properties in the temperature range -50 to 250 .deg. C is offered by duplex stainless steel. However, undesirable secondary precipitation phase such as σ, γ 2 and Cr 2 N may taken place at the cooling stage from the welding processes. Therefore, this paper describes the influence of different welding procedures such as manual metal arc welding (MMA), tungsten inert gas welding (TIG) and vacuum brazing on corrosion resistance of the welded joint for UNS S31803 duplex stainless steel. Microstructure and chemical compositions of the welded joint were examined. The weight loss of specimens immersed in 6% FeCl 3 solution at 47.5 .deg. C for 24-hours was determined and used to evaluate the pitting resistance of duplex stainless steel and their welds. The region of heat-affected zone of specimen obtained by the MMA is much wider than that resulted from TIG, therefore, the weight loss of welds by MMA was larger than that of weld by TIG. The weight loss of brazed specimens cooled from slow cooling rate was larger than those of specimens cooled from high cooling rate, because the precipitation of σ phase. Beside that, the weight loss of brazed specimen is greater than those of the welded specimens. The galvanic corrosion was observed in brazed duplex stainless steel joints in the chloride solution

Comparative crystallization and preliminary X-ray diffraction studies of locked nucleic acid and RNA stems of a tenascin C-binding aptamer

International Nuclear Information System (INIS)

Förster, Charlotte; Brauer, Arnd B. E.; Brode, Svenja; Schmidt, Kathrin S.; Perbandt, Markus; Meyer, Arne; Rypniewski, Wojciech; Betzel, Christian; Kurreck, Jens; Fürste, Jens P.; Erdmann, Volker A.

2006-01-01

Locked nucleic acid (LNA) nucleotides are RNA analogues with a useful additional conformational constraint; the current investigation will provide the first crystallographic view of an all-LNA duplex. The pharmacokinetic properties of an aptamer against the tumour-marker protein tenascin-C have recently been successfully improved by the introduction of locked nucleic acids (LNAs) into the terminal stem of the aptamer. Since it is believed that this post-SELEX optimization is likely to provide a more general route to enhance the in vitro and in vivo stability of aptamers, elucidation of the structural basis of this improvement was embarked upon. Here, the crystallographic and X-ray diffraction data of the isolated aptamer stem encompassed in a six-base-pair duplex both with and without the LNA modification are presented. The obtained all-LNA crystals belong to space group P4 1 2 1 2 or P4 3 2 1 2, with unit-cell parameters a = b = 52.80, c = 62.83 Å; the all-RNA crystals belong to space group R32, with unit-cell parameters a = b = 45.21, c = 186.97 Å, γ = 120.00°

Tribological properties of duplex MAO/DLC coatings on magnesium alloy using combined microarc oxidation and filtered cathodic arc deposition

International Nuclear Information System (INIS)

Liang Jun; Wang Peng; Hu Litian; Hao Jingcheng

2007-01-01

The combined microarc oxidation (MAO) and filtered cathode arc deposition process was used to deposit duplex MAO/DLC coating on AM60B magnesium alloy. The microstructure and composition of the resulting duplex coating were analyzed by Raman spectroscopy, X-ray photoelectron spectroscope (XPS) and scanning electron microscope (SEM). The tribological behaviors of the duplex coating were studied by ball-on-disk friction testing. It is found that the Ti-doped DLC thin film could be successfully deposited onto the polished MAO coating. The duplex MAO/DLC coating exhibits a better tribological property than the DLC or MAO monolayer on Mg alloy substrate, owing to the MAO coating served as an intermediate layer provides improved load support for the soft Mg alloy substrate and the DLC top coating exhibits low friction coefficient

Duplex tube steam reformer development program

International Nuclear Information System (INIS)

Lewe, C.K.; Nieto, J.M.; Papadopoulos, A.

1978-09-01

Work done in partial fulfillment of Task 7 of the Duplex Steam Reformer Development Program is described. The DSR concept acts as a double barrier between a process heat high temperature reactor plant (PNP) and a closed loop chemical heat pipe (CHP) for the long distance transport of chemical energy to a remote industrial user. The current state of the DSR design is described as well as related systems and equipment. The PNP concept presented is based upon work currently underway in the Federal Republic of Germany

High-temperature fracture toughness of duplex microstructures

International Nuclear Information System (INIS)

French, J.D.; Chan, H.M.; Harmer, M.P.; Miller, G.A.

1996-01-01

The temperature dependence of the fracture toughness of ceramics exhibiting duplex microstructures was studied relative to their single-phase constituents using two test methods: bend testing of chevron-notched beams, and the indentation-crack-length technique. The two materials systems studied were Al 2 O 3 :c-ZrO 2 (Y) and Al 2 O 3 :Y 3 Al 5 O 12 (YAG), and the testing temperature ranged from room temperature to 1,200 C. The study showed that in both systems the duplex materials showed higher toughness values than their single-phase constituents above 800 C. This result was attributed to the contribution of low-energy interphase boundaries to the overall composite toughness. Indentation crack length measurements gave toughness values and trends comparable to those determined by the chevron-notched beam method. By comparing the results of the two test methods it was possible to demonstrate that the indentation calibration constant (ξ) shows no significant temperature or material dependence. For the zirconia-containing materials, however, indentation at elevated temperatures is accompanied by significant localized plasticity, which suppressed the radial cracking. Under such conditions, some caution is warranted, since localized plasticity can lead to an overestimation of the fracture toughness

The RNA template channel of the RNA-dependent RNA polymerase as a target for development of antiviral therapy of multiple genera within a virus family.

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Lonneke van der Linden

2015-03-01

Full Text Available The genus Enterovirus of the family Picornaviridae contains many important human pathogens (e.g., poliovirus, coxsackievirus, rhinovirus, and enterovirus 71 for which no antiviral drugs are available. The viral RNA-dependent RNA polymerase is an attractive target for antiviral therapy. Nucleoside-based inhibitors have broad-spectrum activity but often exhibit off-target effects. Most non-nucleoside inhibitors (NNIs target surface cavities, which are structurally more flexible than the nucleotide-binding pocket, and hence have a more narrow spectrum of activity and are more prone to resistance development. Here, we report a novel NNI, GPC-N114 (2,2'-[(4-chloro-1,2-phenylenebis(oxy]bis(5-nitro-benzonitrile with broad-spectrum activity against enteroviruses and cardioviruses (another genus in the picornavirus family. Surprisingly, coxsackievirus B3 (CVB3 and poliovirus displayed a high genetic barrier to resistance against GPC-N114. By contrast, EMCV, a cardiovirus, rapidly acquired resistance due to mutations in 3Dpol. In vitro polymerase activity assays showed that GPC-N114 i inhibited the elongation activity of recombinant CVB3 and EMCV 3Dpol, (ii had reduced activity against EMCV 3Dpol with the resistance mutations, and (iii was most efficient in inhibiting 3Dpol when added before the RNA template-primer duplex. Elucidation of a crystal structure of the inhibitor bound to CVB3 3Dpol confirmed the RNA-binding channel as the target for GPC-N114. Docking studies of the compound into the crystal structures of the compound-resistant EMCV 3Dpol mutants suggested that the resistant phenotype is due to subtle changes that interfere with the binding of GPC-N114 but not of the RNA template-primer. In conclusion, this study presents the first NNI that targets the RNA template channel of the picornavirus polymerase and identifies a new pocket that can be used for the design of broad-spectrum inhibitors. Moreover, this study provides important new insight

Aortoiliac reconstructive surgery based upon the results of duplex scanning

NARCIS (Netherlands)

van der Zaag, E. S.; Legemate, D. A.; Nguyen, T.; Balm, R.; Jacobs, M. J.

1998-01-01

OBJECTIVE: To evaluate whether duplex scanning can replace angiography in patients operated for aortoiliac obstructive disease. DESIGN: Retrospective. MATERIALS AND METHODS: Between January 1995 and October 1996, 44 patients underwent vascular surgery of the aortoiliac tract. The study population

Surveillance Duplex Ultrasonography of Stent Grafts for Popliteal Aneurysms.

Science.gov (United States)

Pineda, Danielle M; Troutman, Douglas A; Dougherty, Matthew J; Calligaro, Keith D

2016-05-01

Stent grafts, also known as covered stents, have become an increasingly acceptable treatment for popliteal artery aneurysms. However, endovascular exclusion confers lower primary patency compared to traditional open bypass and exclusion. The purpose of this study was to evaluate whether duplex ultrasonography (DU) can reliably diagnose failing stent grafts placed for popliteal artery aneurysms prior to occlusion. Between June 5, 2007, and March 11, 2014, 21 stent grafts (Viabahn; Gore, Flagstaff, Arizona) were placed in 19 patients for popliteal artery aneurysms. All patients had at least 1 follow-up duplex scan postoperatively. Mean follow-up was 28.9 months (9-93 months). Postoperative DU surveillance was performed in our Intersocietal Accreditation Commission noninvasive vascular laboratory at 1 week postprocedure and every 6 months thereafter. Duplex ultrasonography measured peak systolic velocities (PSVs) and ratio of adjacent PSVs (Vr) every 5 cm within the stent graft and adjacent arteries. We retrospectively classified the following factors as "abnormal DU findings": focal PSV > 300 cm/s, uniform PSVs 3.0. These DU criteria were derived from laboratory-specific data that we previously published on failing stent grafts placed for lower extremity occlusive disease. Four of the 21 stent grafts presented with symptomatic graft thrombosis within 6 months of a normal DU. Three of these 4 patients presented with rest pain and underwent thrombectomy (2) or vein bypass (1), and 1 elected for nonintervention for claudication. Our results suggest that surveillance DU using criteria established for grafts placed for occlusive disease may not be useful for predicting stent graft failure in popliteal artery aneurysms. © The Author(s) 2016.

Relationship between microstructure and fracture types in a UNS S32205 duplex stainless steel

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Maria Victoria Biezma

2013-01-01

Full Text Available Duplex stainless steels are susceptible to the formation of sigma phase at high temperature which could potentially be responsible for catastrophic service failure of components. Thermal treatments were applied to duplex stainless steels in order to promote the precipitation of different fractions of sigma phase into a ferrite-austenite microstructure. Quantitative image analysis was employed to characterize the microstructure and Charpy impact tests were used in order to evaluate the mechanical degradation caused by sigma phase presence. The fracture morphology of the Charpy test specimens were thoroughly observed in SEM, looking for a correlation between the microstructure and the fracture types in UNS S32205 duplex stainless steel. The main conclusion is the strong embrittlement effect of sigma phase since it is possible to observe a transition from transgranular fracture to intergranular fracture as increases the percentage of sigma phase. Thus, the mixed modes of fracture are predominant in the present study with high dependence on sigma phase percentages obtained by different thermal treatments.

Chirality- and sequence-selective successive self-sorting via specific homo- and complementary-duplex formations

Science.gov (United States)

Makiguchi, Wataru; Tanabe, Junki; Yamada, Hidekazu; Iida, Hiroki; Taura, Daisuke; Ousaka, Naoki; Yashima, Eiji

2015-01-01

Self-recognition and self-discrimination within complex mixtures are of fundamental importance in biological systems, which entirely rely on the preprogrammed monomer sequences and homochirality of biological macromolecules. Here we report artificial chirality- and sequence-selective successive self-sorting of chiral dimeric strands bearing carboxylic acid or amidine groups joined by chiral amide linkers with different sequences through homo- and complementary-duplex formations. A mixture of carboxylic acid dimers linked by racemic-1,2-cyclohexane bis-amides with different amide sequences (NHCO or CONH) self-associate to form homoduplexes in a completely sequence-selective way, the structures of which are different from each other depending on the linker amide sequences. The further addition of an enantiopure amide-linked amidine dimer to a mixture of the racemic carboxylic acid dimers resulted in the formation of a single optically pure complementary duplex with a 100% diastereoselectivity and complete sequence specificity stabilized by the amidinium–carboxylate salt bridges, leading to the perfect chirality- and sequence-selective duplex formation. PMID:26051291

The effect of fiber laser parameters on microhardness and microstructure of duplex stainless steel

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Mohammed Ghusoon R.

2017-01-01

Full Text Available An investigation was implement to study the influence of laser power, and speed of the welding on hardness, microstructure, and penetration of laser welding bead on plate duplex stainless steel, which is not exhibited so far. A fiber laser was selected for welding duplex stainless steel sheet with 2 mm thickness. Then, optical microscope (OM was used in the morphologic observation of cross section, penetration depth, and bead width. Microhardness of the welded sheet was measured using Vickers hardness. Profiles of hardness and microstructure were utilized to discriminate welding line and to propose superior welding parameters. The experimental results displayed that, a good quality of duplex steel welds can be acquired when a suitable fiber laser welding parameters were selected. It was found that microhardness profiles showed a rise in the hardness of the weld and heat-affected zones as the solidification process proceeds rapidly. Additionally, the crystal solidification process induced by the fiber laser welding was schematically clarified and systematically exposed.

Arabidopsis COLD SHOCK DOMAIN PROTEIN2 is a RNA chaperone that is regulated by cold and developmental signals

International Nuclear Information System (INIS)

Sasaki, Kentaro; Kim, Myung-Hee; Imai, Ryozo

2007-01-01

Bacterial cold shock proteins (CSPs) are RNA chaperones that unwind RNA secondary structures. Arabidopsis COLD SHOCK DOMAIN PROTEIN2 (AtCSP2) contains a domain that is shared with bacterial CSPs. Here we showed that AtCSP2 binds to RNA and unwinds nucleic acid duplex. Heterologous expression of AtCSP2 complemented cold sensitivity of an Escherichia coli csp quadruple mutant, indicating that AtCSP2 function as a RNA chaperone in E. coli. AtCSP2 mRNA and protein levels increased during cold acclimation, but the protein accumulation was most prominent after 10 days of cold treatment. AtCSP2 promoter::GUS transgenic plants revealed that AtCSP2 is expressed only in root and shoot apical regions during vegetative growth but is expressed in reproductive organs such as pollens, ovules and embryos. These data indicated that AtCSP2 is involved in developmental processes as well as cold adaptation. Localization of AtCSP2::GFP in nucleolus and cytoplasm suggested different nuclear and cytosolic RNA targets

Chemically modified oligonucleotides with efficient RNase H response

DEFF Research Database (Denmark)

Vester, Birte; Boel, Anne Marie; Lobedanz, Sune

2008-01-01

Ten different chemically modified nucleosides were incorporated into short DNA strands (chimeric oligonucleotides ON3-ON12 and ON15-ON24) and then tested for their capacity to mediate RNAse H cleavage of the complementary RNA strand. The modifications were placed at two central positions directly...... in the RNase H cleaving region. The RNA strand of duplexes with ON3, ON5 and ON12 were cleaved more efficiently than the RNA strand of the DNA:RNA control duplex. There seems to be no correlation between the thermal stability between the duplexes and RNase H cleavage....

An exploration of sequence specific DNA-duplex/pyrene interactions for intercalated and surface-associated pyrene species. Final report, May 1, 1993--December 31, 1996

Energy Technology Data Exchange (ETDEWEB)

Netzel, T.L.

1997-03-01

The broad objective of this DOE sponsored work on photoinduced electron transfer (ET) within covalently modified DNA was to learn about the rates of Et among various DNA bases and commonly used organic electron donor (D) and acceptor (A) molecules. This hypothesis driven, multidisciplinary project combined skills in modified nucleic acid synthesis and in continuous and time-resolved optical spectroscopies. Covalently modified DNA chemistry as investigated in this program had two specific long term goals. The first was to use experimental and theoretical insights into the mechanisms of electron transfer (ET) reactions to design supramolecular assemblies of redox-active chromophores that function as efficient vectorial ET engines. The second was to construct oligonucleotide probes for real-time monitoring of intracellular processes involving DNA and RNA such as m-RNA expression and translocation. This research project laid the groundwork for studying ET reactions within DNA duplexes by examining the photophysics of uridine nucleosides which are covalently labeled at the 5-position with 1-pyrenyl chromophores.

Duplex correlation phlebography in venous mapping of the upper limbs for artery venous fistulas for hemodialysis

International Nuclear Information System (INIS)

Esperon Percovich, A.; Lopez Chapuis, D.; Velverdu, M.; Curi, J.; Sciuto, F.; Velverdu, M.; Curi, J.

1995-01-01

When clinical evaluation is not enough,the evaluation of the venous condition of the upper limbs for the realization of angio access for hemodialysis is classically based on phlebography,an invasive,risky method.the appear rance of non invasive techniques such as eco Doppler(duplex) makes it necessary to do research in order to determine the utility of the method and define its indications.The authors analyse 35 venous mappings of the upper limbs by phlebography and duplex and compare its results for the different venous regions.They come to the conclusion that duplex presented the best performance for the hum ero axillary subclavian region,detecting thrombosis with a sensitivity of 100% a specificity of 97% positive predictive value of 50% and negative predictive value of 100%.For superficial axis (radial and superficial ulnar,basilic and cephalic)there is low sensitivity for the determination of presence and permeability of the axis but 100% specificity.Duplex was not useful for the description of veins in order to determine utility for Avf.Finally,the authors make recommendations as regards indications of these para clinical tests [es

Misinterpreting the therapeutic effects of small interfering RNA caused by immune stimulation.

Science.gov (United States)

Robbins, Marjorie; Judge, Adam; Ambegia, Ellen; Choi, Catherine; Yaworski, Ed; Palmer, Lorne; McClintock, Kevin; MacLachlan, Ian

2008-10-01

Activation of innate immunity has direct effects in modulating viral replication, tumor growth, angiogenesis, and inflammatory and other immunological processes. It is now established that unmodified siRNA can activate this innate immune response and therefore there is real potential for siRNA to elicit nonspecific therapeutic effects in a wide range of disease models. Here we demonstrate that in a murine model of influenza infection, the antiviral activity of siRNA is due primarily to immune stimulation elicited by the active siRNA duplexes and is not the result of therapeutic RNA interference (RNAi) as previously reported. We show that the misinterpretation stems from the use of a particular control green fluorescent protein (GFP) siRNA that we identify as having unusually low immunostimulatory activity compared with the active anti-influenza siRNA. Curiously, this GFP siRNA has served as a negative control for a surprising number of groups reporting therapeutic effects of siRNA. The inert immunologic profile of the GFP sequence was unique among a broad panel of published siRNAs, all of which could elicit significant interferon induction from primary immune cells. This panel included eight active siRNAs against viral, angiogenic, and oncologic targets, the reported therapeutic efficacy of which was based on comparison with the nonimmunostimulatory GFP siRNA. These results emphasize the need for researchers to anticipate, monitor, and adequately control for siRNA-mediated immune stimulation and calls into question the interpretation of numerous published reports of therapeutic RNAi in vivo. The use of chemically modified siRNA with minimal immunostimulatory capacity will help to delineate more accurately the mechanism of action underlying such studies.

Comprehensive Educational Assessment for the States: The Duplex Design.

Science.gov (United States)

Bock, R. Darrell; Mislevy, Robert

State testing programs often attempt to provide annual information for use in student guidance and qualification, school and program evaluation, and broad policy decisions. With the development of a new type of assessment instrument, the "duplex design," the several functions of state testing programs can be served in a single test…

Crystal structure of metallo DNA duplex containing consecutive Watson-Crick-like T-Hg(II)-T base pairs.

Science.gov (United States)

Kondo, Jiro; Yamada, Tom; Hirose, Chika; Okamoto, Itaru; Tanaka, Yoshiyuki; Ono, Akira

2014-02-24

The metallo DNA duplex containing mercury-mediated T-T base pairs is an attractive biomacromolecular nanomaterial which can be applied to nanodevices such as ion sensors. Reported herein is the first crystal structure of a B-form DNA duplex containing two consecutive T-Hg(II)-T base pairs. The Hg(II) ion occupies the center between two T residues. The N3-Hg(II) bond distance is 2.0 Å. The relatively short Hg(II)-Hg(II) distance (3.3 Å) observed in consecutive T-Hg(II)-T base pairs suggests that the metallophilic attraction could exist between them and may stabilize the B-form double helix. To support this, the DNA duplex is largely distorted and adopts an unusual nonhelical conformation in the absence of Hg(II). The structure of the metallo DNA duplex itself and the Hg(II)-induced structural switching from the nonhelical form to the B-form provide the basis for structure-based design of metal-conjugated nucleic acid nanomaterials. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A duplex endpoint PCR assay for rapid detection and differentiation of Leptospira strains.

Science.gov (United States)

Benacer, Douadi; Zain, Siti Nursheena Mohd; Lewis, John W; Khalid, Mohd Khairul Nizam Mohd; Thong, Kwai Lin

2017-01-01

This study aimed to develop a duplex endpoint PCR assay for rapid detection and differentiation of Leptospira strains. Primers were designed to target the rrs (LG1/LG2) and ligB (LP1/LP2) genes to confirm the presence of the Leptospira genus and the pathogenic species, respectively. The assay showed 100% specificity against 17 Leptospira strains with a limit of detection of 23.1pg/µl of leptospiral DNA and sensitivity of 103 leptospires/ml in both spiked urine and water. Our duplex endpoint PCR assay is suitable for rapid early detection of Leptospira with high sensitivity and specificity.

Use of bacterially expressed dsRNA to downregulate Entamoeba histolytica gene expression.

Directory of Open Access Journals (Sweden)

Carlos F Solis

Full Text Available BACKGROUND: Modern RNA interference (RNAi methodologies using small interfering RNA (siRNA oligonucleotide duplexes or episomally synthesized hairpin RNA are valuable tools for the analysis of gene function in the protozoan parasite Entamoeba histolytica. However, these approaches still require time-consuming procedures including transfection and drug selection, or costly synthetic molecules. PRINCIPAL FINDINGS: Here we report an efficient and handy alternative for E. histolytica gene down-regulation mediated by bacterial double-stranded RNA (dsRNA targeting parasite genes. The Escherichia coli strain HT115 which is unable to degrade dsRNA, was genetically engineered to produce high quantities of long dsRNA segments targeting the genes that encode E. histolytica beta-tubulin and virulence factor KERP1. Trophozoites cultured in vitro were directly fed with dsRNA-expressing bacteria or soaked with purified dsRNA. Both dsRNA delivery methods resulted in significant reduction of protein expression. In vitro host cell-parasite assays showed that efficient downregulation of kerp1 gene expression mediated by bacterial dsRNA resulted in significant reduction of parasite adhesion and lytic capabilities, thus supporting a major role for KERP1 in the pathogenic process. Furthermore, treatment of trophozoites cultured in microtiter plates, with a repertoire of eighty-five distinct bacterial dsRNA segments targeting E. histolytica genes with unknown function, led to the identification of three genes potentially involved in the growth of the parasite. CONCLUSIONS: Our results showed that the use of bacterial dsRNA is a powerful method for the study of gene function in E. histolytica. This dsRNA delivery method is also technically suitable for the study of a large number of genes, thus opening interesting perspectives for the identification of novel drug and vaccine targets.

Impact deformation behavior of duplex and superaustenitic stainless steels welds by split Hopkinson pressure bar

Science.gov (United States)

Wang, Shing-Hoa; Huang, Chih-Sheng; Lee, Woei-Shyan; Chen, Tao-Hsing; Wu, Chia-Chang; Lien, Charles; Tsai, Hung-Yin

2009-12-01

A considerable volume of γ phase increases in the fusion zone (weld metal) for two duplex stainless steels after a high-strain-rate impact. The strain-induced γ phase formation in the fusion zone results in local hardness variation depending on the strain rate. The α phase content in the fusion zone decreases as the impact strain rate increases for SAF 2205 DSS and SAF 2507 DSS. The results of the two-phase content measured by Ferritoscope correspond to that assessed by image analyses. In contrast, superaustenite stainless steel is unaffected by such an impact owing to its fully stable austenization. Impacted welds at a high strain rate of 5 × 103 s-1 reveal feather-like surface creases along the solidified curved columnar grain boundaries. The apparent surface creases are formed due to the presence of diffuse Lüders bands, which are caused by heavy plastic deformation in coarse-grain materials.

Temporal Translational Control by a Metastable RNA Structure

DEFF Research Database (Denmark)

Møller-Jensen, Jakob; Franch, Thomas; Gerdes, Kenn

2001-01-01

Programmed cell death by the hok/sok locus of plasmid R1 relies on a complex translational control mechanism. The highly stable hok mRNA is activated by 3'-end exonucleolytical processing. Removal of the mRNA 3' end releases a 5'-end sequence that triggers refolding of the mRNA. The refolded hok m......-transcriptional control mechanism....

Position dependent mismatch discrimination on DNA microarrays – experiments and model

Directory of Open Access Journals (Sweden)

Michel Wolfgang

2008-12-01

Full Text Available Abstract Background The propensity of oligonucleotide strands to form stable duplexes with complementary sequences is fundamental to a variety of biological and biotechnological processes as various as microRNA signalling, microarray hybridization and PCR. Yet our understanding of oligonucleotide hybridization, in particular in presence of surfaces, is rather limited. Here we use oligonucleotide microarrays made in-house by optically controlled DNA synthesis to produce probe sets comprising all possible single base mismatches and base bulges for each of 20 sequence motifs under study. Results We observe that mismatch discrimination is mostly determined by the defect position (relative to the duplex ends as well as by the sequence context. We investigate the thermodynamics of the oligonucleotide duplexes on the basis of double-ended molecular zipper. Theoretical predictions of defect positional influence as well as long range sequence influence agree well with the experimental results. Conclusion Molecular zipping at thermodynamic equilibrium explains the binding affinity of mismatched DNA duplexes on microarrays well. The position dependent nearest neighbor model (PDNN can be inferred from it. Quantitative understanding of microarray experiments from first principles is in reach.

Microstructural characterization of thermally-aged duplex stainless steels

International Nuclear Information System (INIS)

Nomoto, A.; Hamaoka, T.; Nishida, K.; Dohi, K.; Soneda, N.

2011-01-01

The embrittlement of duplex stainless steels is of concern for the long term operation of light water reactors. The objectives of this work was to characterize solute atom distribution in ferrite phase of thermally aged duplex stainless steels by using atom tomography probe and to measure the hardness of ferrite phase by using nano-indentation technique. This series of slides highlights 4 main conclusions. First, phase separation quickly evolves and then slows down during the thermal ageing. Secondly, precipitates are formed after ageing for 1000 hr at 400 C and 2000 hr at 350 C. The clusters become larger with time at 400 C. Chemical composition of the clusters do not change very much with cluster size and ageing time at 400 C. Thirdly, no cluster formation is observed in the materials aged at 450 C. It is likely that precipitation occurs faster than phase separation at lower temperatures. Fourthly, hardness changes are well described by combining the contributions of phase separation and G phase formation. 'Variation' is a good parameter to describe hardness change due to phase separation. Contribution of G-phase needs to be considered separately

Effect of solution treatment on microstructure and properties of duplex stainless steel

Science.gov (United States)

Wang, X. Y.; Luo, J. M.; Huang, L. Q.; Wang, H. B.; Ma, C. W.

2017-09-01

The influence of solution treatment on microstructure and properties of 2205 duplex stainless steel (DSS) was studied. The microstructure, precipitates and corrosion resisting property were observed and analyzed by means of optical microscopy (OM), scanning electron microscopy (SEM) and electrochemical methods. The results showed that a large number of brittle σ-phase precipitates, which deteriorate the plasticity and corrosion resistance of the material, were easy to produce in the duplex stainless steel under the low temperature. The precipitation of σ-phase can be decreased and the plasticity and corrosion resistance can be improved by increasing solution temperature. In addition, the ferrite content increases with the increase of solution temperature, while less affected by cooling rate.

An Optimal Analysis in Wireless Powered Full-duplex Relaying Network

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K.-T. Nguyen

2017-04-01

Full Text Available Wireless-powered cellular networks (WPCNs are currently being investigated to exploit the reliability and improve battery lifetime of mobile users. This paper investigates the energy harvesting structure of the full-duplex relaying networks. By using the time switching based relaying (TSR protocol and Amplify-and-Forward (AF model in delay-limited transmission scheme, we propose the closed-form expression of the outage probability and then calculate the optimal throughput. An important result can be taken obviously that the time fraction in TSR, the position of relay, the noise as well as the energy conversation impacting on the outage probability as well as the optimal throughput. By Monte Carlo simulation, the numerical results indicate an effective relaying strategy in full-duplex cooperative systems. Finally, we provide fundamental design guidelines for selecting time fraction in TSR that satisfies the requirements of a practical relaying system.

Fracture mechanics evaluation of cast duplex stainless steel after thermal aging

International Nuclear Information System (INIS)

Tujikura, Y.; Urata, S.

1999-01-01

For the primary coolant piping of PWRs in Japan, cast duplex stainless steel, which is excellent in terms of strength, corrosion resistance and weldability, has conventionally been used. Cast duplex stainless steel contains the ferrite phase in the austenite matrix, and thermal aging after long-term service is known to decrease fracture toughness. Therefore, we evaluated the integrity of the primary coolant piping for an initial PWR plant in Japan by means of elastic plastic fracture mechanics. The evaluation results show that the crack will not grow into an unstable fracture and the integrity of the piping will be secure, even when such through-wall crack length is assumed to be as large as the fatigue crack length grown for a service period of up to 60 years. (orig.)

Fracture mechanics evaluation of cast duplex stainless steel after thermal aging

Energy Technology Data Exchange (ETDEWEB)

Tujikura, Y.; Urata, S. [Kansai Electr. Power Co., Inc., Osaka (Japan). General Office of Nucl. and Fossil Power Production

1999-07-01

For the primary coolant piping of PWRs in Japan, cast duplex stainless steel, which is excellent in terms of strength, corrosion resistance and weldability, has conventionally been used. Cast duplex stainless steel contains the ferrite phase in the austenite matrix, and thermal aging after long-term service is known to decrease fracture toughness. Therefore, we evaluated the integrity of the primary coolant piping for an initial PWR plant in Japan by means of elastic plastic fracture mechanics. The evaluation results show that the crack will not grow into an unstable fracture and the integrity of the piping will be secure, even when such through-wall crack length is assumed to be as large as the fatigue crack length grown for a service period of up to 60 years. (orig.)

Natural selection and algorithmic design of mRNA.

Science.gov (United States)

Cohen, Barry; Skiena, Steven

2003-01-01

Messenger RNA (mRNA) sequences serve as templates for proteins according to the triplet code, in which each of the 4(3) = 64 different codons (sequences of three consecutive nucleotide bases) in RNA either terminate transcription or map to one of the 20 different amino acids (or residues) which build up proteins. Because there are more codons than residues, there is inherent redundancy in the coding. Certain residues (e.g., tryptophan) have only a single corresponding codon, while other residues (e.g., arginine) have as many as six corresponding codons. This freedom implies that the number of possible RNA sequences coding for a given protein grows exponentially in the length of the protein. Thus nature has wide latitude to select among mRNA sequences which are informationally equivalent, but structurally and energetically divergent. In this paper, we explore how nature takes advantage of this freedom and how to algorithmically design structures more energetically favorable than have been built through natural selection. In particular: (1) Natural Selection--we perform the first large-scale computational experiment comparing the stability of mRNA sequences from a variety of organisms to random synonymous sequences which respect the codon preferences of the organism. This experiment was conducted on over 27,000 sequences from 34 microbial species with 36 genomic structures. We provide evidence that in all genomic structures highly stable sequences are disproportionately abundant, and in 19 of 36 cases highly unstable sequences are disproportionately abundant. This suggests that the stability of mRNA sequences is subject to natural selection. (2) Artificial Selection--motivated by these biological results, we examine the algorithmic problem of designing the most stable and unstable mRNA sequences which code for a target protein. We give a polynomial-time dynamic programming solution to the most stable sequence problem (MSSP), which is asymptotically no more complex

Downlink Error Rates of Half-duplex Users in Full-duplex Networks over a Laplacian Inter-User Interference Limited and EGK fading

KAUST Repository

Soury, Hamza

2017-03-14

This paper develops a mathematical framework to study downlink error rates and throughput for half-duplex (HD) terminals served by a full-duplex (FD) base station (BS). The developed model is used to motivate long term pairing for users that have non-line of sight (NLOS) interfering link. Consequently, we study the interferer limited problem that appears between NLOS HD users-pair that are scheduled on the same FD channel. The distribution of the interference is first characterized via its distribution function, which is derived in closed form. Then, a comprehensive performance assessment for the proposed pairing scheme is provided by assuming Extended Generalized- $cal{K}$ (EGK) fading for the downlink and studying different modulation schemes. To this end, a unified closed form expression for the average symbol error rate is derived. Furthermore, we show the effective downlink throughput gain harvested by the pairing NLOS users as a function of the average signal-to-interferenceratio when compared to an idealized HD scenario with neither interference nor noise. Finally, we show the minimum required channel gain pairing threshold to harvest downlink throughput via the FD operation when compared to the HD case for each modulation scheme.

Implementation of real-time duplex synthetic aperture ultrasonography

DEFF Research Database (Denmark)

Hemmsen, Martin Christian; Larsen, Lee; Kjeldsen, Thomas

2015-01-01

This paper presents a real-time duplex synthetic aperture imaging system, implemented on a commercially available tablet. This includes real-time wireless reception of ultrasound signals and GPU processing for B-mode and Color Flow Imaging (CFM). The objective of the work is to investigate the im...... and that the required bandwidth between the probe and processing unit is within the current Wi-Fi standards....

Study of miRNA Based Gene Regulation, Involved in Solid Cancer, by the Assistance of Argonaute Protein

Directory of Open Access Journals (Sweden)

Surya Narayan Rath

2016-09-01

Full Text Available Solid tumor is generally observed in tissues of epithelial or endothelial cells of lung, breast, prostate, pancreases, colorectal, stomach, and bladder, where several genes transcription is regulated by the microRNAs (miRNAs. Argonaute (AGO protein is a family of protein which assists in miRNAs to bind with mRNAs of the target genes. Hence, study of the binding mechanism between AGO protein and miRNAs, and also with miRNAs-mRNAs duplex is crucial for understanding the RNA silencing mechanism. In the current work, 64 genes and 23 miRNAs have been selected from literatures, whose deregulation is well established in seven types of solid cancer like lung, breast, prostate, pancreases, colorectal, stomach, and bladder cancer. In silico study reveals, miRNAs namely, miR-106a, miR-21, and miR-29b-2 have a strong binding affinity towards PTEN, TGFBR2, and VEGFA genes, respectively, suggested as important factors in RNA silencing mechanism. Furthermore, interaction between AGO protein (PDB ID-3F73, chain A with selected miRNAs and with miRNAs-mRNAs duplex were studied computationally to understand their binding at molecular level. The residual interaction and hydrogen bonding are inspected in Discovery Studio 3.5 suites. The current investigation throws light on understanding miRNAs based gene silencing mechanism in solid cancer.

Numerical modeling and optimization of machining duplex stainless steels

Directory of Open Access Journals (Sweden)

Rastee D. Koyee

2015-01-01

Full Text Available The shortcomings of the machining analytical and empirical models in combination with the industry demands have to be fulfilled. A three-dimensional finite element modeling (FEM introduces an attractive alternative to bridge the gap between pure empirical and fundamental scientific quantities, and fulfill the industry needs. However, the challenging aspects which hinder the successful adoption of FEM in the machining sector of manufacturing industry have to be solved first. One of the greatest challenges is the identification of the correct set of machining simulation input parameters. This study presents a new methodology to inversely calculate the input parameters when simulating the machining of standard duplex EN 1.4462 and super duplex EN 1.4410 stainless steels. JMatPro software is first used to model elastic–viscoplastic and physical work material behavior. In order to effectively obtain an optimum set of inversely identified friction coefficients, thermal contact conductance, Cockcroft–Latham critical damage value, percentage reduction in flow stress, and Taylor–Quinney coefficient, Taguchi-VIKOR coupled with Firefly Algorithm Neural Network System is applied. The optimization procedure effectively minimizes the overall differences between the experimentally measured performances such as cutting forces, tool nose temperature and chip thickness, and the numerically obtained ones at any specified cutting condition. The optimum set of input parameter is verified and used for the next step of 3D-FEM application. In the next stage of the study, design of experiments, numerical simulations, and fuzzy rule modeling approaches are employed to optimize types of chip breaker, insert shapes, process conditions, cutting parameters, and tool orientation angles based on many important performances. Through this study, not only a new methodology in defining the optimal set of controllable parameters for turning simulations is introduced, but also

RNA interference-based therapeutics for human immunodeficiency virus HIV-1 treatment: synthetic siRNA or vector-based shRNA?

Science.gov (United States)

Subramanya, Sandesh; Kim, Sang-Soo; Manjunath, N; Shankar, Premlata

2010-02-01

Despite the clinical benefits of highly active antiretroviral therapy (HAART), the prospect of life-long antiretroviral treatment poses significant problems, which has spurred interest in developing new drugs and strategies to treat HIV infection and eliminate persistent viral reservoirs. RNAi has emerged as a therapeutic possibility for HIV. We discuss progress in overcoming hurdles to translating transient and stable RNAi enabling technologies to clinical application for HIV; covering the past 2 - 3 years. HIV inhibition can be achieved by transfection of chemically or enzymatically synthesized siRNAs or by DNA-based vector systems expressing short hairpin RNAs (shRNAs) that are processed intracellularly into siRNA. We compare these approaches, focusing on technical and safety issues that will guide the choice of strategy for clinical use. Introduction of synthetic siRNA into cells or its stable endogenous production using vector-driven shRNA have been shown to suppress HIV replication in vitro and, in some instances, in vivo. Each method has advantages and limitations in terms of ease of delivery, duration of silencing, emergence of escape mutants and potential toxicity. Both appear to have potential as future therapeutics for HIV, once the technical and safety issues of each approach are overcome.

Duplex-imprinted nano well arrays for promising nanoparticle assembly

Science.gov (United States)

Li, Xiangping; Manz, Andreas

2018-02-01

A large area nano-duplex-imprint technique is presented in this contribution using natural cicada wings as stamps. The glassy wings of the cicada, which are abundant in nature, exhibit strikingly interesting nanopillar structures over their membrane. This technique, with excellent performance despite the nonplanar surface of the wings, combines both top-down and bottom-up nanofabrication techniques. It transitions micro-nanofabrication from a cleanroom environment to the bench. Two different materials, dicing tape with an acrylic layer and a UV optical adhesive, are used to make replications at the same time, thus achieving duplex imprinting. The promise of a large volume of commercial manufacturing of these nanostructure elements can be envisaged through this contribution to speeding up the fabrication process and achieving a higher throughput. The contact angle of the replicated nanowell arrays before and after oxygen plasma was measured. Gold nanoparticles (50 nm) were used to test how the nanoparticles behaved on the untreated and plasma-treated replica surface. The experiments show that promising nanoparticle self-assembly can be obtained.

Efficacy of duplex ultrasound surveillance after infrainguinal vein bypass may be enhanced by identification of characteristics predictive of graft stenosis development.

Science.gov (United States)

Tinder, Chelsey N; Chavanpun, Joe P; Bandyk, Dennis F; Armstrong, Paul A; Back, Martin R; Johnson, Brad L; Shames, Murray L

2008-09-01

Controversy regarding the efficacy of duplex ultrasound surveillance after infrainguinal vein bypass led to an analysis of patient and bypass graft characteristics predictive for development of graft stenosis and a decision of secondary intervention. Retrospective analysis of a contemporary, consecutive series of 353 clinically successful infrainguinal vein bypasses performed in 329 patients for critical (n = 284; 80%) or noncritical (n = 69; 20%) limb ischemia enrolled in a surveillance program to identify and repair duplex-detected graft stenosis. Variables correlated with graft stenosis and bypass repair included: procedure indication, conduit type (saphenous vs nonsaphenous vein; reversed vs nonreversed orientation), prior bypass graft failure, postoperative ankle-brachial index (ABI) < 0.85, and interpretation of the first duplex surveillance study as "normal" or "abnormal" based on peak systolic velocity (PSV) and velocity ratio (Vr) criteria. Overall, 126 (36%) of the 353 infrainguinal bypasses had 174 secondary interventions (endovascular, 100; surgery, 74) based on duplex surveillance; resulting in 3-year Kaplan-Meier primary (46%), assisted-primary (80%), and secondary (81%) patency rates. Characteristics predictive of duplex-detected stenosis leading to intervention (PSV: 443 +/- 94 cm/s; Vr: 8.6 +/- 9) were: "abnormal" initial duplex testing indicating moderate (PSV: 180-300 cm/s, Vr: 2-3.5) stenosis (P < .0001), non-single segment saphenous vein conduit (P < .01), warfarin drug therapy (P < .01), and redo bypass grafting (P < .001). Procedure indication, postoperative ABI level, statin drug therapy, and vein conduit orientation were not predictive of graft revision. The natural history of 141 (40%) bypasses with an abnormal first duplex scan differed from "normal" grafts by more frequent (51% vs 24%, P < .001) and earlier (7 months vs 11 months) graft revision for severe stenosis and a lower 3-year assisted primary patency (68% vs 87%; P < .001). In 52

Duplex ultrasonography in the hemorrhagic fever with renal syndrome; Correlation with laboratory findings

International Nuclear Information System (INIS)

Han, Chun Hee; Cho, K. S.; Auh, Y. h.; Park, C. S.; Park, S. K.; Kim, S. B.

1994-01-01

Assuming that the duplex Doppler sonography might be useful in predicting the disease evolution of hemorrhagic fever with renal syndrome, we compared the resistive index (RI) with the clinical and laboratory findings in 18 patients. We underwent 30 duplex Doppler examinations in 18 patients: one examination in nine, two examinations in six, and three examinations in three patients. Duplex Dopper waveforms were obtained from the main, segmental,interlobar, and arcuate arteries of both kidneys, and the RI was calculated for each study. In oliguric phase, the mean RI was high (average, 0.94), and the serum BUN(averate, 92.3mg/dl) and creatinine(average, 10.4mg/dl) levels were elevated. In diuretic phase the mean RI was normalized (average, 0.7), and the serum BUN(average, 31.1mg/dl)and serum creatinine (average, 2.9mg/dl) levels were low. There was statistically significant correlation between the mean RI and the serum levels of BUN and creatinine and 24 hour urine output (P<0.001). We conclude that the mean RI is a useful indicator in predicting the disease evolution in patients with hemorrhagic fever with renal syndrome

Effects of fabrication conditions on mechanical properties and microstructure of duplex β″-Al2O3 solid electrolyte

International Nuclear Information System (INIS)

Canfield, Nathan L.; Kim, Jin Y.; Bonnett, Jeff F.; Pearson, R.L.; Sprenkle, Vincent L.; Jung, Keeyoung

2015-01-01

Highlights: • The concept of duplex BASEs is presented as a method to lower the ASR for NBBs. • Duplex BASEs consist of thin dense electrolyte and porous support. • Strength of converted BASEs shows a different trend from as-sintered samples. • Cell orientation gives significant impact on strength of duplex BASEs. - Abstract: Na-beta batteries are an attractive technology as a large-scale electrical energy storage for grid applications. However, additional improvements in performance and cost are needed for wide market penetration. To improve cell performance by minimizing polarizations, reduction of electrolyte thickness was attempted using a duplex structure consisting of a thin dense electrolyte layer and a porous support layer. In this paper, the effects of sintering conditions, dense electrolyte thickness, and cell orientation on the flexural strength of duplex BASEs fabricated using a vapor phase approach were investigated. It is shown that sintering at temperatures between 1500 and 1550 °C results in fine grained microstructures and the highest flexural strength after conversion. Increasing thickness of the dense electrolyte has a small impact on flexural strength, while the orientation of load such that the dense electrolyte is in tension instead of compression has major effects on strength for samples with a well-sintered dense electrolyte

Validation of a novel venous duplex ultrasound objective structured assessment of technical skills for the assessment of venous reflux.

Science.gov (United States)

Jaffer, Usman; Normahani, Pasha; Lackenby, Kimberly; Aslam, Mohammed; Standfield, Nigel J

2015-01-01

Duplex ultrasound measurement of reflux time is central to the diagnosis of venous incompetence. We have developed an assessment tool for Duplex measurement of venous reflux for both simulator and patient-based training. A novel assessment tool, Venous Duplex Ultrasound Assessment of Technical Skills (V-DUOSATS), was developed. A modified DUOSATS was used for simulator training. Participants of varying skill level were invited to viewed an instructional video and were allowed ample time to familiarize with the Duplex equipment. Attempts made by the participants were recorded and independently assessed by 3 expert assessors and 5 novice assessors using the modified V-DUOSATS. "Global" assessment was also done by expert assessors on a 4-point Likert scale. Content, construct, and concurrent validities as well as reliability were evaluated. Content and construct validity as well as reliability were demonstrated. Receiver operator characteristic analysis-established cut points of 19/22 and 21/30 were most appropriate for simulator and patient-based assessment, respectively. We have validated a novel assessment tool for Duplex venous reflux measurement. Further work is required to establish transference validity of simulator training to improve skill in scanning patients. We have developed and validated V-DUOSATS for simulator training. Copyright © 2015 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

Role of routine pre-operative screening venous duplex ultrasound in morbidly obese patients undergoing bariatric surgery

Directory of Open Access Journals (Sweden)

P Praveen Raj

2017-01-01

Full Text Available Background/Aims: It is well established that obesity is a strongly associated risk factor for post-operative deep vein thrombosis (DVT. Physical effects and pro-thrombotic, pro-inflammatory and hypofibrinolytic effects of severe obesity may predispose to idiopathic DVT (pre-operatively because of which bariatric patients are routinely screened before surgery. The aim of this study was to audit the use of routine screening venous duplex ultrasound in morbidly obese patients before undergoing bariatric surgery. Methods: We retrospectively reviewed 180 patients who underwent bariatric surgery from August 2013 to August 2014 who had undergone pre-operative screening bilateral lower-extremity venous duplex ultrasound for DVT. Data were collected on patient's demographics, history of venous thromboembolism, prior surgeries and duplex ultrasound details of the status of the deep veins and superficial veins of the lower limbs. Results: No patients had symptoms or signs of DVT pre-operatively. No patient gave history of DVT. No patient was found to have iliac, femoral or popliteal vein thrombosis. Superficial venous disease was found in 17 (8%. One patient had a right lower limb venous ulcer. Conclusion: Thromboembolic problems in the morbidly obese before bariatric surgery are infrequent, and screening venous duplex ultrasound can be done in high-risk patients only.

Linking phylogenetic identities of bacteria to starch fermentation in an in vitro model of the large intestine by RNA-based stable isotope probing.

Science.gov (United States)

Kovatcheva-Datchary, Petia; Egert, Markus; Maathuis, Annet; Rajilić-Stojanović, Mirjana; de Graaf, Albert A; Smidt, Hauke; de Vos, Willem M; Venema, Koen

2009-04-01

Carbohydrates, including starches, are an important energy source for humans, and are known for their interactions with the microbiota in the digestive tract. Largely, those interactions are thought to promote human health. Using 16S ribosomal RNA (rRNA)-based stable isotope probing (SIP), we identified starch-fermenting bacteria under human colon-like conditions. To the microbiota of the TIM-2 in vitro model of the human colon 7.4 g l(-1) of [U-(13)C]-starch was added. RNA extracted from lumen samples after 0 (control), 2, 4 and 8 h was subjected to density-gradient ultracentrifugation. Terminal-restriction fragment length polymorphism (T-RFLP) fingerprinting and phylogenetic analyses of the labelled and unlabelled 16S rRNA suggested populations related to Ruminococcus bromii, Prevotella spp. and Eubacterium rectale to be involved in starch metabolism. Additionally, 16S rRNA related to that of Bifidobacterium adolescentis was abundant in all analysed fractions. While this might be due to the enrichment of high-GC RNA in high-density fractions, it could also indicate an active role in starch fermentation. Comparison of the T-RFLP fingerprints of experiments performed with labelled and unlabelled starch revealed Ruminococcus bromii as the primary degrader in starch fermentation in the studied model, as it was found to solely predominate in the labelled fractions. LC-MS analyses of the lumen and dialysate samples showed that, for both experiments, starch fermentation primarily yielded acetate, butyrate and propionate. Integration of molecular and metabolite data suggests metabolic cross-feeding in the system, where populations related to Ruminococcus bromii are the primary starch degrader, while those related to Prevotella spp., Bifidobacterium adolescentis and Eubacterium rectale might be further involved in the trophic chain.

A sensitive duplex nanoparticle-assisted PCR assay for identifying porcine epidemic diarrhea virus and porcine transmissible gastroenteritis virus from clinical specimens.

Science.gov (United States)

Zhu, Yu; Liang, Lin; Luo, Yakun; Wang, Guihua; Wang, Chunren; Cui, Yudong; Ai, Xia; Cui, Shangjin

2017-02-01

In this study, a novel duplex nanoparticle-assisted polymerase chain reaction (nanoPCR) assay was developed to detect porcine epidemic diarrhea virus (PEDV) and porcine transmissible gastroenteritis virus (TGEV). Two pairs of primers were designed based on the conserved region within the N gene of PEDV and TGEV. In a screening of 114 clinical samples from four provinces in China for PEDV and TGEV, 48.2 and 3.5 % of the samples, respectively, tested positive. Under optimized conditions, the duplex nanoPCR assay had a detection limit of 7.6 × 10 1 and 8.5 × 10 1 copies μL -1 for PEDV and TGEV, respectively. The sensitivity of the duplex nanoPCR assay was ten times higher than that of a conventional PCR assay. Moreover, no fragments were amplified when the duplex nanoPCR assay was used to test samples containing other porcine viruses. Our results indicate that the duplex nanoPCR assay described here is useful for the rapid detection of PEDV and TGEV and can be applied in clinical diagnosis.

Long-Range Vibrational Dynamics Are Directed by Watson-Crick Base Pairing in Duplex DNA.

Science.gov (United States)

Hithell, Gordon; Shaw, Daniel J; Donaldson, Paul M; Greetham, Gregory M; Towrie, Michael; Burley, Glenn A; Parker, Anthony W; Hunt, Neil T

2016-05-05

Ultrafast two-dimensional infrared (2D-IR) spectroscopy of a 15-mer A-T DNA duplex in solution has revealed structure-dependent vibrational coupling and energy transfer processes linking bases with the sugar-phosphate backbone. Duplex melting induces significant changes in the positions of off-diagonal peaks linking carbonyl and ring-stretching vibrational modes of the adenine and thymine bases with vibrations of the phosphate group and phosphodiester linkage. These indicate that Watson-Crick hydrogen bonding and helix formation lead to a unique vibrational coupling arrangement of base vibrational modes with those of the phosphate unit. On the basis of observations from time-resolved 2D-IR data, we conclude that rapid energy transfer processes occur between base and backbone, mediated by additional modes located on the deoxyribose moiety within the same nucleotide. These relaxation dynamics are insensitive to duplex melting, showing that efficient intramolecular energy relaxation to the solvent via the phosphate groups is the key to excess energy dissipation in both single- and double-stranded DNA.

Environmental Degradation of Dissimilar Austenitic 316L and Duplex 2205 Stainless Steels Welded Joints

Directory of Open Access Journals (Sweden)

Topolska S.

2017-12-01

Full Text Available The paper describes structure and properties of dissimilar stainless steels welded joints between duplex 2205 and austenitic 316L steels. Investigations were focused on environmentally assisted cracking of welded joints. The susceptibility to stress corrosion cracking (SCC and hydrogen embrittlement was determined in slow strain rate tests (SSRT with the strain rate of 2.2 × 10−6 s−1. Chloride-inducted SCC was determined in the 35% boiling water solution of MgCl2 environment at 125°C. Hydrogen assisted SCC tests were performed in synthetic sea water under cathodic polarization condition. It was shown that place of the lowest resistance to chloride stress corrosion cracking is heat affected zone at duplex steel side of dissimilar joins. That phenomenon was connected with undesirable structure of HAZ comprising of large fractions of ferrite grains with acicular austenite phase. Hydrogen assisted SCC tests showed significant reduction in ductility of duplex 2205 steel while austenitic 316L steel remains almost immune to degradation processes. SSR tests of dissimilar welded joints revealed a fracture in the area of austenitic steel.

[Correlation between RNA Expression Level and Early PMI in Human Brain Tissue].

Science.gov (United States)

Lü, Y H; Ma, K J; Li, Z H; Gu, J; Bao, J Y; Yang, Z F; Gao, J; Zeng, Y; Tao, L; Chen, L

2016-08-01

To explore the correlation between the expression levels of several RNA markers in human brain tissue and early postmortem interval （PMI）. Twelve individuals with known PMI （range from 4.3 to 22.5 h） were selected and total RNA was extracted from brain tissue. Eight commonly used RNA markers were chosen including β -actin, GAPDH, RPS29, 18S rRNA, 5S rRNA, U6 snRNA, miRNA-9 and miRNA-125b, and the expression levels were detected in brain tissue by real-time fluorescent quantitative PCR. The internal reference markers with stable expression in early PMI were screened using geNorm software and the relationship between its expression level and some relevant factors such as age, gender and cause of death were analyzed. RNA markers normalized by internal reference were inserted into the mathematic model established by previous research for PMI estimation using R software. Model quality was judged by the error rate calculated with estimated PMI. 5S rRNA, miRNA-9 and miRNA-125b showed quite stable expression and their expression levels had no relation with age, gender and cause of death. The error rate of estimated PMI using β -actin was 24.6%, while GAPDH was 41.0%. 5S rRNA, miRNA-9 and miRNA-125b are suitable as internal reference markers of human brain tissue owing to their stable expression in early PMI. The expression level of β -actin correlates well with PMI, which can be used as an additional index for early PMI estimation. Copyright© by the Editorial Department of Journal of Forensic Medicine

ON SECURE FULL DUPLEX COMMUNICATION IN MOBILE AD HOC NETWORK

OpenAIRE

S. C. Dutta; Sudha Singh; D. K. Singh

2013-01-01

This paper is to establish Ad Hoc network in mobile phones and start fully secured full duplex communication in any situation. This type of communication will be cost effective and it will be fastest way of communication in case of any server failure or server error.