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Sample records for dna relieves torsional

  1. In the absence of writhe, DNA relieves torsional stress with localized, sequence-dependent structural failure to preserve B-form

    PubMed Central

    Randall, Graham L.; Zechiedrich, Lynn; Pettitt, B. Montgomery

    2009-01-01

    To understand how underwinding and overwinding the DNA helix affects its structure, we simulated 19 independent DNA systems with fixed degrees of twist using molecular dynamics in a system that does not allow writhe. Underwinding DNA induced spontaneous, sequence-dependent base flipping and local denaturation, while overwinding DNA induced the formation of Pauling-like DNA (P-DNA). The winding resulted in a bimodal state simultaneously including local structural failure and B-form DNA for both underwinding and extreme overwinding. Our simulations suggest that base flipping and local denaturation may provide a landscape influencing protein recognition of DNA sequence to affect, for examples, replication, transcription and recombination. Additionally, our findings help explain results from single-molecule experiments and demonstrate that elastic rod models are strictly valid on average only for unstressed or overwound DNA up to P-DNA formation. Finally, our data support a model in which base flipping can result from torsional stress. PMID:19586933

  2. In the Absence of Writhe, DNA Relieves Torsional Stress with Localized, Sequence-Dependent Structural Failure to Preserve B-form

    SciTech Connect

    Randall, Graham L.; Zechiedrich, E. L.; Pettitt, Bernard M.

    2009-09-01

    To understand how underwinding and overwinding the DNA helix affects its structure, we simulated 19 independent DNA systems with fixed degrees of twist using molecular dynamics in a system that does not allow writhe. Underwinding DNA induced spontaneous, sequence-dependent base flipping and local denaturation, while overwinding DNA induced the formation of Pauling-like DNA (P-DNA). The winding resulted in a bimodal state simultaneously including local structural failure and B-form DNA for both underwinding and extreme overwinding. Our simulations suggest that base flipping and local denaturation may provide a landscape influencing protein recognition of DNA sequence to affect, for examples, replication, transcription and recombination. Additionally, our findings help explain results from singlemolecule experiments and demonstrate that elastic rod models are strictly valid on average only for unstressed or overwound DNA up to P-DNA formation. Finally, our data support a model in which base flipping can result from torsional stress.

  3. Modeling DNA Thermodynamics under Torsional Stress

    PubMed Central

    Wang, Qian; Pettitt, B. Montgomery

    2014-01-01

    Negatively twisted DNA is essential to many biological functions. Due to torsional stress, duplex DNA can have local, sequence-dependent structural defects. In this work, a thermodynamic model of DNA was built to qualitatively predict the local sequence-dependent mechanical instabilities under torsional stress. The results were compared to both simulation of a coarse-grained model and experiment results. By using the Kirkwood superposition approximation, we built an analytical model to represent the free energy difference ΔW of a hydrogen-bonded basepair between the B-form helical state and the basepair opened (or locally melted) state, within a given sequence under torsional stress. We showed that ΔW can be well approximated by two-body interactions with its nearest-sequence-neighbor basepairs plus a free energy correction due to long-range correlations. This model is capable of rapidly predicting the position and thermodynamics of local defects in a given sequence. The result qualitatively matches with an in vitro experiment for a long DNA sequence (>4000 basepairs). The 12 parameters used in this model can be further quantitatively refined when more experimental data are available. PMID:24606942

  4. Modeling DNA thermodynamics under torsional stress.

    PubMed

    Wang, Qian; Pettitt, B Montgomery

    2014-03-01

    Negatively twisted DNA is essential to many biological functions. Due to torsional stress, duplex DNA can have local, sequence-dependent structural defects. In this work, a thermodynamic model of DNA was built to qualitatively predict the local sequence-dependent mechanical instabilities under torsional stress. The results were compared to both simulation of a coarse-grained model and experiment results. By using the Kirkwood superposition approximation, we built an analytical model to represent the free energy difference ΔW of a hydrogen-bonded basepair between the B-form helical state and the basepair opened (or locally melted) state, within a given sequence under torsional stress. We showed that ΔW can be well approximated by two-body interactions with its nearest-sequence-neighbor basepairs plus a free energy correction due to long-range correlations. This model is capable of rapidly predicting the position and thermodynamics of local defects in a given sequence. The result qualitatively matches with an in vitro experiment for a long DNA sequence (>4000 basepairs). The 12 parameters used in this model can be further quantitatively refined when more experimental data are available. PMID:24606942

  5. Unravelling the structural plasticity of stretched DNA under torsional constraint

    NASA Astrophysics Data System (ADS)

    King, Graeme A.; Peterman, Erwin J. G.; Wuite, Gijs J. L.

    2016-06-01

    Regions of the genome are often held under torsional constraint. Nevertheless, the influence of such constraint on DNA-protein interactions during genome metabolism is still poorly understood. Here using a combined optical tweezers and fluorescence microscope, we quantify and explain how torsional constraint influences the structural stability of DNA under applied tension. We provide direct evidence that concomitant basepair melting and helical unwinding can occur in torsionally constrained DNA at forces >~50 pN. This striking result indicates that local changes in linking number can be absorbed by the rest of the DNA duplex. We also present compelling new evidence that an overwound DNA structure (likely P-DNA) is created (alongside underwound structures) at forces >~110 pN. These findings substantiate previous theoretical predictions and highlight a remarkable structural plasticity of torsionally constrained DNA. Such plasticity may be required in vivo to absorb local changes in linking number in DNA held under torsional constraint.

  6. Unravelling the structural plasticity of stretched DNA under torsional constraint.

    PubMed

    King, Graeme A; Peterman, Erwin J G; Wuite, Gijs J L

    2016-01-01

    Regions of the genome are often held under torsional constraint. Nevertheless, the influence of such constraint on DNA-protein interactions during genome metabolism is still poorly understood. Here using a combined optical tweezers and fluorescence microscope, we quantify and explain how torsional constraint influences the structural stability of DNA under applied tension. We provide direct evidence that concomitant basepair melting and helical unwinding can occur in torsionally constrained DNA at forces >∼50 pN. This striking result indicates that local changes in linking number can be absorbed by the rest of the DNA duplex. We also present compelling new evidence that an overwound DNA structure (likely P-DNA) is created (alongside underwound structures) at forces >∼110 pN. These findings substantiate previous theoretical predictions and highlight a remarkable structural plasticity of torsionally constrained DNA. Such plasticity may be required in vivo to absorb local changes in linking number in DNA held under torsional constraint. PMID:27263853

  7. Unravelling the structural plasticity of stretched DNA under torsional constraint

    PubMed Central

    King, Graeme A.; Peterman, Erwin J. G.; Wuite, Gijs J. L.

    2016-01-01

    Regions of the genome are often held under torsional constraint. Nevertheless, the influence of such constraint on DNA–protein interactions during genome metabolism is still poorly understood. Here using a combined optical tweezers and fluorescence microscope, we quantify and explain how torsional constraint influences the structural stability of DNA under applied tension. We provide direct evidence that concomitant basepair melting and helical unwinding can occur in torsionally constrained DNA at forces >∼50 pN. This striking result indicates that local changes in linking number can be absorbed by the rest of the DNA duplex. We also present compelling new evidence that an overwound DNA structure (likely P-DNA) is created (alongside underwound structures) at forces >∼110 pN. These findings substantiate previous theoretical predictions and highlight a remarkable structural plasticity of torsionally constrained DNA. Such plasticity may be required in vivo to absorb local changes in linking number in DNA held under torsional constraint. PMID:27263853

  8. Torsional Buckling and Writhing Dynamics of Elastic Cables and DNA

    SciTech Connect

    Goyal, S; Perkins, N C; Lee, C L

    2003-02-14

    Marine cables under low tension and torsion on the sea floor can undergo a dynamic buckling process during which torsional strain energy is converted to bending strain energy. The resulting three-dimensional cable geometries can be highly contorted and include loops and tangles. Similar geometries are known to exist for supercoiled DNA and these also arise from the conversion of torsional strain energy to bending strain energy or, kinematically, a conversion of twist to writhe. A dynamic form of Kirchhoff rod theory is presented herein that captures these nonlinear dynamic processes. The resulting theory is discretized using the generalized-method for finite differencing in both space and time. The important kinematics of cross-section rotation are described using an incremental rotation ''vector'' as opposed to traditional Euler angles or Euler parameters. Numerical solutions are presented for an example system of a cable subjected to increasing twist at one end. The solutions show the dynamic evolution of the cable from an initially straight element, through a buckled element in the approximate form of a helix, and through the dynamic collapse of this helix through a looped form.

  9. Studies of torsional properties of DNA and nucleosomes using angular optical trapping

    NASA Astrophysics Data System (ADS)

    Sheinin, Maxim Y.

    DNA in vivo is subjected to torsional stress due to the action of molecular motors and other DNA-binding proteins. Several decades of research have uncovered the fascinating diversity of DNA transformations under torsion and the important role they play in the regulation of vital cellular processes such as transcription and replication. Recent studies have also suggested that torsion can influence the structure and stability of nucleosomes---basic building blocks of the eukaryotic genome. However, our understanding of the impact of torsion is far from being complete due to significant experimental challenges. In this work we have used a powerful single-molecule experimental technique, angular optical trapping, to address several long-standing issues in the field of DNA and nucleosome mechanics. First, we utilized the high resolution and direct torque measuring capability of the angular optical trapping to precisely measure DNA twist-stretch coupling. Second, we characterized DNA melting under tension and torsion. We found that torsionally underwound DNA forms a left-handed structure, significantly more flexible compared to the regular B-DNA. Finally, we performed the first comprehensive investigation of the single nucleosome behavior under torque and force. Importantly, we discovered that positive torque causes significant dimer loss, which can have implications for transcription through chromatin.

  10. Pain Relievers

    MedlinePlus

    Pain relievers are medicines that reduce or relieve headaches, sore muscles, arthritis, or other aches and pains. There ... also have a slightly different response to a pain reliever. Over-the-counter (OTC) medicines are good for ...

  11. Annealed Random Copolymer Model of the B-Z Transition in DNA: Torsional Responses

    PubMed Central

    Kwon, Ah-Young; Lee, Nam-Kyung; Hong, Seok-Cheol; Fierling, Julien; Johner, Albert

    2015-01-01

    Both in vivo and in vitro, specific sequences in double-stranded DNA can adopt the left-handed Z-form when underwound. Recently, the B-Z transition of DNA has been studied in detail in magnetic tweezers experiments by several groups. We present a theoretical description of this transition, based on an annealed random copolymer model. The transition of a switchable sequence is discussed as a function of energetic and geometric parameters of the B- and Z-forms, of the applied boundary conditions, and of the characteristics of the B-Z interface. We address a possible torsional softening upon the B-Z transition. The model can be also applied to other biofilaments with annealed torsional/flexural degrees of freedom. PMID:25992734

  12. The conductive properties of single DNA molecules studied by torsion tunneling atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Wang, W.; Niu, D. X.; Jiang, C. R.; Yang, X. J.

    2014-01-01

    The conductive properties of single natural λ-DNA molecules are studied by torsion tunneling atomic force microscopy (TR-TUNA). The currents both parallel to and perpendicular to the DNA chains are investigated, but only weak or even no current signals are detected by TR-TUNA. To improve the conductance of DNA molecules, silver and copper metallized DNAs are fabricated and their conductivities are checked by TR-TUNA. It is found that for both Cu- and Ag-DNAs, the conductivity perpendicular to the DNA chain is enhanced significantly as the metal clusters are attached to the DNA chains. But parallel to the chain the electrical transport is still weak, most probably due to the ‘beads-on-a-string’ constructions of metallized DNAs.

  13. Could humic acid relieve the biochemical toxicities and DNA damage caused by nickel and deltamethrin in earthworms (Eisenia foetida)?

    PubMed

    Shen, Chen-Chao; Shen, Dong-Sheng; Shentu, Jia-Li; Wang, Mei-Zhen; Wan, Ming-Yang

    2015-12-01

    The aim of the study was to determine whether humic acid (HA) prevented gene and biochemical toxic effects in earthworms (Eisenia foetida) exposed to nickel and deltamethrin (at 100 and 1 mg kg(-1), respectively) in soil. Cellular- and molecular-level toxic effects of nickel and deltamethrin in earthworms were evaluated by measuring damage to lipid membranes and DNA and the production of protein carbonyls over 42 days of exposure. Nickel and deltamethrin induced significant levels of oxidative stress in earthworms, increasing the production of peroxidation products (malondialdehyde and protein carbonyls) and increasing the comet assay tail DNA% (determined by single-cell gel electrophoresis). DNA damage was the most sensitive of the three indices because it gave a higher sample/control ratio than did the other indices. The presence of HA alleviated (in decreasing order of effectiveness) damage to DNA, proteins, and lipid membranes caused by nickel and deltamethrin. A low HA dose (0.5-1% HA in soil) prevented a great deal of lipid membrane damage, but the highest HA dose (3% HA in soil) prevented still more DNA damage. However, the malondialdehyde concentrations in earthworms were higher at the highest HA dose than at the lower HA doses. The amounts of protein carbonyls produced at different HA doses were not significantly different. The toxic effects to earthworms caused by increased oxidizable nickel concentrations could be relieved by adding HA. PMID:26511644

  14. Chromatin regulates DNA torsional energy via topoisomerase II-mediated relaxation of positive supercoils

    PubMed Central

    Fernández, Xavier; Díaz-Ingelmo, Ofelia; Martínez-García, Belén; Roca, Joaquim

    2014-01-01

    Eukaryotic topoisomerases I (topo I) and II (topo II) relax the positive (+) and negative (−) DNA torsional stress (TS) generated ahead and behind the transcription machinery. It is unknown how this DNA relaxation activity is regulated and whether (+) and (−)TS are reduced at similar rates. Here, we used yeast circular minichromosomes to conduct the first comparative analysis of topo I and topo II activities in relaxing chromatin under (+) and (−)TS. We observed that, while topo I relaxed (+) and (−)TS with similar efficiency, topo II was more proficient and relaxed (+)TS more quickly than (−)TS. Accordingly, we found that the relaxation rate of (+)TS by endogenous topoisomerases largely surpassed that of (−)TS. We propose a model of how distinct conformations of chromatin under (+) and (−)TS may produce this unbalanced relaxation of DNA. We postulate that, while quick relaxation of (+)TS may facilitate the progression of RNA and DNA polymerases, slow relaxation of (−)TS may serve to favor DNA unwinding and other structural transitions at specific regions often required for genomic transactions. PMID:24859967

  15. DNAaseI-hypersensitive minichromosomes of SV40 possess an elastic torsional strain in DNA.

    PubMed Central

    Luchnik, A N; Bakayev, V V; Yugai, A A; Zbarsky, I B; Georgiev, G P

    1985-01-01

    Previously, we have shown that DNA in a small fraction (2-5%) of SV40 minichromosomes was torsionally strained and could be relaxed by treating minichromosomes with topoisomerase I. This fraction was enriched with endogeneous RNA polymerase II (Luchnik et al., 1982, EMBO J., 1, 1353). Here we show that one and the same fraction of SV40 minichromosomes is hypersensitive to DNAase I and is relaxable by topoisomerase I. Moreover, this fraction completely loses its hypersensitivity to DNAase I upon relaxation. The possibility that this fraction of minichromosomes can be represented by naked DNA is ruled out by the results of studying the kinetics of minichromosome digestion by DNAase I in comparison to digestion of pure SV40 DNA and by measuring the buoyant density of SV40 chromatin in equilibrium CsCl gradient. Our data obtained with SV40 minichromosomes may be relevant to the mechanism responsible for DNAase I hypersensitivity in the loops or domains of cellular chromatin. Images PMID:2987817

  16. How topoisomerase IV can efficiently unknot and decatenate negatively supercoiled DNA molecules without causing their torsional relaxation.

    PubMed

    Rawdon, Eric J; Dorier, Julien; Racko, Dusan; Millett, Kenneth C; Stasiak, Andrzej

    2016-06-01

    Freshly replicated DNA molecules initially form multiply interlinked right-handed catenanes. In bacteria, these catenated molecules become supercoiled by DNA gyrase before they undergo a complete decatenation by topoisomerase IV (Topo IV). Topo IV is also involved in the unknotting of supercoiled DNA molecules. Using Metropolis Monte Carlo simulations, we investigate the shapes of supercoiled DNA molecules that are either knotted or catenated. We are especially interested in understanding how Topo IV can unknot right-handed knots and decatenate right-handed catenanes without acting on right-handed plectonemes in negatively supercoiled DNA molecules. To this end, we investigate how the topological consequences of intersegmental passages depend on the geometry of the DNA-DNA juxtapositions at which these passages occur. We observe that there are interesting differences between the geometries of DNA-DNA juxtapositions in the interwound portions and in the knotted or catenated portions of the studied molecules. In particular, in negatively supercoiled, multiply interlinked, right-handed catenanes, we detect specific regions where DNA segments belonging to two freshly replicated sister DNA molecules form left-handed crossings. We propose that, due to its geometrical preference to act on left-handed crossings, Topo IV can specifically unknot supercoiled DNA, as well as decatenate postreplicative catenanes, without causing their torsional relaxation. PMID:27106058

  17. How topoisomerase IV can efficiently unknot and decatenate negatively supercoiled DNA molecules without causing their torsional relaxation

    PubMed Central

    Rawdon, Eric J.; Dorier, Julien; Racko, Dusan; Millett, Kenneth C.; Stasiak, Andrzej

    2016-01-01

    Freshly replicated DNA molecules initially form multiply interlinked right-handed catenanes. In bacteria, these catenated molecules become supercoiled by DNA gyrase before they undergo a complete decatenation by topoisomerase IV (Topo IV). Topo IV is also involved in the unknotting of supercoiled DNA molecules. Using Metropolis Monte Carlo simulations, we investigate the shapes of supercoiled DNA molecules that are either knotted or catenated. We are especially interested in understanding how Topo IV can unknot right-handed knots and decatenate right-handed catenanes without acting on right-handed plectonemes in negatively supercoiled DNA molecules. To this end, we investigate how the topological consequences of intersegmental passages depend on the geometry of the DNA-DNA juxtapositions at which these passages occur. We observe that there are interesting differences between the geometries of DNA-DNA juxtapositions in the interwound portions and in the knotted or catenated portions of the studied molecules. In particular, in negatively supercoiled, multiply interlinked, right-handed catenanes, we detect specific regions where DNA segments belonging to two freshly replicated sister DNA molecules form left-handed crossings. We propose that, due to its geometrical preference to act on left-handed crossings, Topo IV can specifically unknot supercoiled DNA, as well as decatenate postreplicative catenanes, without causing their torsional relaxation. PMID:27106058

  18. Sequence-specific transitions of the torsion angle gamma change the polar-hydrophobic profile of the DNA grooves: implication for indirect protein-DNA recognition.

    PubMed

    Zhitnikova, Mariia Yu; Boryskina, Olena P; Shestopalova, Anna V

    2014-01-01

    Variations of the shape and polarity of the DNA grooves caused by changes of the DNA conformation play an important role in the DNA readout. Despite the fact that non-canonical trans and gauche- conformations of the DNA backbone angle γ (O5'-C5'-C4'-C3') are frequently found in the DNA crystal structures, their possible role in the DNA recognition has not been studied systematically. In order to fill in this gap, we analyze the available high-resolution crystal structures of the naked and complexed DNA. The analysis shows that the non-canonical γ angle conformations are present both in the naked and bound DNA, more often in the bound vs. naked DNA, and in the nucleotides with the A-like vs. the B-like sugar pucker. The alternative angle γ torsions are more frequently observed in the purines with the A-like sugar pucker and in the pyrimidines with the B-like sugar conformation. The minor groove of the nucleotides with non-canonical γ angle conformation is more polar, while the major groove is more hydrophobic than in the nucleotides with the classical γ torsions due to variations in exposure of the polar and hydrophobic groups of the DNA backbone. The propensity of the nucleotides with different γ angle conformations to participate in the protein-nucleic acid contacts in the minor and major grooves is connected with their sugar pucker and sequence-specific. Our findings imply that the angle γ transitions contribute to the process of the protein-DNA recognition due to modification of the polar/hydrophobic profile of the DNA grooves. PMID:23998351

  19. Refinement of the Sugar-Phosphate Backbone Torsion Beta for AMBER Force Fields Improves the Description of Z- and B-DNA.

    PubMed

    Zgarbová, Marie; Šponer, Jiří; Otyepka, Michal; Cheatham, Thomas E; Galindo-Murillo, Rodrigo; Jurečka, Petr

    2015-12-01

    Z-DNA duplexes are a particularly complicated test case for current force fields. We performed a set of explicit solvent molecular dynamics (MD) simulations with various AMBER force field parametrizations including our recent refinements of the ε/ζ and glycosidic torsions. None of these force fields described the ZI/ZII and other backbone substates correctly, and all of them underpredicted the population of the important ZI substate. We show that this underprediction can be attributed to an inaccurate potential for the sugar-phosphate backbone torsion angle β. We suggest a refinement of this potential, β(OL1), which was derived using our recently introduced methodology that includes conformation-dependent solvation effects. The new potential significantly increases the stability of the dominant ZI backbone substate and improves the overall description of the Z-DNA backbone. It also has a positive (albeit small) impact on another important DNA form, the antiparallel guanine quadruplex (G-DNA), and improves the description of the canonical B-DNA backbone by increasing the population of BII backbone substates, providing a better agreement with experiment. We recommend using β(OL1) in combination with our previously introduced corrections, εζ(OL1) and χ(OL4), (the combination being named OL15) as a possible alternative to the current β torsion potential for more accurate modeling of nucleic acids. PMID:26588601

  20. Positional dependence of transcriptional inhibition by DNA torsional stress in yeast chromosomes.

    PubMed

    Joshi, Ricky S; Piña, Benjamin; Roca, Joaquim

    2010-02-17

    How DNA helical tension is constrained along the linear chromosomes of eukaryotic cells is poorly understood. In this study, we induced the accumulation of DNA (+) helical tension in Saccharomyces cerevisiae cells and examined how DNA transcription was affected along yeast chromosomes. The results revealed that, whereas the overwinding of DNA produced a general impairment of transcription initiation, genes situated at <100 kb from the chromosomal ends gradually escaped from the transcription stall. This novel positional effect seemed to be a simple function of the gene distance to the telomere: It occurred evenly in all 32 chromosome extremities and was independent of the atypical structure and transcription activity of subtelomeric chromatin. These results suggest that DNA helical tension dissipates at chromosomal ends and, therefore, provides a functional indication that yeast chromosome extremities are topologically open. The gradual escape from the transcription stall along the chromosomal flanks also indicates that friction restrictions to DNA twist diffusion, rather than tight topological boundaries, might suffice to confine DNA helical tension along eukaryotic chromatin. PMID:20057354

  1. Positional dependence of transcriptional inhibition by DNA torsional stress in yeast chromosomes

    PubMed Central

    Joshi, Ricky S; Piña, Benjamin; Roca, Joaquim

    2010-01-01

    How DNA helical tension is constrained along the linear chromosomes of eukaryotic cells is poorly understood. In this study, we induced the accumulation of DNA (+) helical tension in Saccharomyces cerevisiae cells and examined how DNA transcription was affected along yeast chromosomes. The results revealed that, whereas the overwinding of DNA produced a general impairment of transcription initiation, genes situated at <100 kb from the chromosomal ends gradually escaped from the transcription stall. This novel positional effect seemed to be a simple function of the gene distance to the telomere: It occurred evenly in all 32 chromosome extremities and was independent of the atypical structure and transcription activity of subtelomeric chromatin. These results suggest that DNA helical tension dissipates at chromosomal ends and, therefore, provides a functional indication that yeast chromosome extremities are topologically open. The gradual escape from the transcription stall along the chromosomal flanks also indicates that friction restrictions to DNA twist diffusion, rather than tight topological boundaries, might suffice to confine DNA helical tension along eukaryotic chromatin. PMID:20057354

  2. Torsional flexibility of B-DNA as revealed by conformational analysis.

    PubMed Central

    Zhurkin, V B; Lysov, Y P; Florentiev, V L; Ivanov, V I

    1982-01-01

    The thermal fluctuations of a regular double helix belonging to the B-family were studied by means of atom-atomic potentials method. The winding angle fluctuation was found to be 2.4 degrees for poly(dA):poly(dT) and 3.0 degrees for poly(dG):poly(dC). The reasonable agreement of these estimations with those obtained experimentally reveals the essential role of the small-amplitude torsional vibrations of atoms in the mechanism of the double helix flexibility. The calculated equilibrium winding angle, tau 0, essentially depends on the degree of neutralization of phosphate groups, being about 35.5 degrees for the full neutralization. The deoxyribose pucker is closely related to the tau angle: while tau proceeds from 30 degrees to 45 degrees the pseudorotation phase angle, P, increases from 126 degrees to 164 degrees. Fluctuations of the angles TL and TW, which specify inclination of the bases to the helix axis, were evaluated to be 5 degrees-10 degrees. Possible correlation between conformational changes in the adjacent nucleotides is discussed. PMID:7071023

  3. Appendicular Torsion

    PubMed Central

    Dubhashi, Siddharth Pramod; Khadav, Bharat

    2016-01-01

    Torsion of the vermiform appendix is a rare condition detectable only at operation. It can be primary or secondary. This is a case report of 52-year-old female with 180° anti-clockwise rotation of the appendix. Torsion can further leads to strangulation and infarction of the organ. Appendicular torsion could be included in the differential diagnosis of pain in right iliac fossa. PMID:27013858

  4. DUPLEX: A molecular mechanics program in torsion angle space for computing structures of DNA and RNA

    SciTech Connect

    Hingerty, B.E.

    1992-07-01

    DUPLEX produces energy minimized structures of DNA and RNA of any base sequence for single and double strands. The smallest subunits are deoxydinucleoside monophosphates, and up to 12 residues, single or double stranded can be treated. In addition, it can incorporate NMR derived interproton distances an constraints in the minimizations. Both upper and lower bounds for these distances can be specified. The program has been designed to run on a UNICOS Cray supercomputer, but should run, albeit slowly, on a laboratory computer such as a VAX or a workstation.

  5. Torsional locomotion

    PubMed Central

    Bigoni, D.; Dal Corso, F.; Misseroni, D.; Bosi, F.

    2014-01-01

    One edge of an elastic rod is inserted into a friction-less and fitting socket head, whereas the other edge is subjected to a torque, generating a uniform twisting moment. It is theoretically shown and experimentally proved that, although perfectly smooth, the constraint realizes an expulsive axial force on the elastic rod, which amount is independent of the shape of the socket head. The axial force explains why screwdrivers at high torque have the tendency to disengage from screw heads and demonstrates torsional locomotion along a perfectly smooth channel. This new type of locomotion finds direct evidence in the realization of a ‘torsional gun’, capable of transforming torque into propulsive force. PMID:25383038

  6. MedlinePlus: Pain Relievers

    MedlinePlus

    ... things you can do to help ease pain. Pain relievers are just one part of a pain treatment plan. Start Here Chronic Pain Medicines (American Academy of Family Physicians) Also in Spanish Pain Relievers: Understanding Your OTC Options (American Academy of Family ...

  7. Variable stiffness torsion springs

    NASA Technical Reports Server (NTRS)

    Alhorn, Dean C. (Inventor); Polites, Michael E. (Inventor)

    1994-01-01

    In a torsion spring the spring action is a result of the relationships between the torque applied in twisting the spring, the angle through which the torsion spring twists, and the modulus of elasticity of the spring material in shear. Torsion springs employed industrially have been strips, rods, or bars, generally termed shafts, capabable of being flexed by twisting their axes. They rely on the variations in shearing forces to furnish an internal restoring torque. In the torsion springs herein the restoring torque is external and therefore independent of the shearing modulus of elasticity of the torsion spring shaft. Also provided herein is a variable stiffness torsion spring. This torsion spring can be so adjusted as to have a given spring constant. Such variable stiffness torsion springs are extremely useful in gimballed payloads such as sensors, telescopes, and electronic devices on such platforms as a space shuttle or a space station.

  8. Variable stiffness torsion springs

    NASA Technical Reports Server (NTRS)

    Alhorn, Dean C. (Inventor); Polites, Michael E. (Inventor)

    1995-01-01

    In a torsion spring the spring action is a result of the relationships between the torque applied in twisting the spring, the angle through which the torsion spring twists, and the modulus of elasticity of the spring material in shear. Torsion springs employed industrially have been strips, rods, or bars, generally termed shafts, capabable of being flexed by twisting their axes. They rely on the variations in shearing forces to furnish an internal restoring torque. In the torsion springs herein the restoring torque is external and therefore independent of the shearing modulus of elasticity of the torsion spring shaft. Also provided herein is a variable stiffness torsion spring. This torsion spring can be so adjusted as to have a given spring constant. Such variable stiffness torsion springs are extremely useful in gimballed payloads such as sensors, telescopes, and electronic devices on such platforms as a space shuttle or a space station.

  9. Stress-relieved solder joints

    NASA Technical Reports Server (NTRS)

    Zemenick, C. J.

    1980-01-01

    Mechanical stress on solder joints is reduced by procedure for soldering electronic components to circuit boards. Procedure was developed for radio-frequency (RF) strip-line circuits, for which dimensions must be carefully controlled to minimize parasitic capacitance and inductance. Procedure consists of loosening component from its mounting after each lead is soldered relieving induced stresses before next soldering step.

  10. Health Hints: Use Caution with Pain Relievers

    MedlinePlus

    ... Resources for You Health Hints: Use Caution with Pain Relievers. Share Tweet Linkedin Pin it More sharing options ... Pin it Email Print PDF version (447KB) (NAPS) -- Pain relievers, when used correctly, are safe and effective. Millions ...

  11. How Do Pain Relievers Work? (For Kids)

    MedlinePlus

    ... White House Lunch Recipes How Do Pain Relievers Work? KidsHealth > For Kids > How Do Pain Relievers Work? Print A A A Text Size en español ¿ ... the spot that hurts so much. Pain relievers work with your cells, your body's nerve endings, your ...

  12. Influence of DNA torsional rigidity on excision of 7,8-dihydro-8-oxo-2′-deoxyguanosine in the presence of opposing abasic sites by human OGG1 protein

    PubMed Central

    Barone, F.; Dogliotti, E.; Cellai, L.; Giordano, C.; Bjørås, M.; Mazzei, F.

    2003-01-01

    The human protein OGG1 (hOGG1) targets the highly mutagenic base 7,8-dihydro-8-oxo-2′-deoxyguanosine (8-oxodG) and shows a high specificity for the opposite DNA base. Abasic sites can arise in DNA in close opposition to 8-oxodG either during repair of mismatched bases (i.e. 8-oxodG/A mismatches) or, more frequently, as a consequence of ionizing radiation exposure. Bistranded DNA lesions may remain unrepaired and lead to cell death via double-strand break formation. In order to explore the role of damaged-DNA dynamics in recognition/excision by the hOGG1 repair protein, specific oligonucleotides containing an 8-oxodG opposite an abasic site, at different relative distances on the complementary strand, were synthesized. Rotational dynamics were studied by means of fluorescence polarization anisotropy decay experiments and the torsional elastic constant as well as the hydrodynamic radius of the DNA fragments were evaluated. Efficiency of excision of 8-oxodG was tested using purified human glycosylase. A close relation between the twisting flexibility of the DNA fragment and the excision efficiency of the oxidative damage by hOGG1 protein within a cluster was found. PMID:12655006

  13. Testicular Torsion (For Parents)

    MedlinePlus

    ... ON THIS TOPIC Hernias Ultrasound: Scrotum Undescended Testicles Male Reproductive System PQ: I have a lump on one of ... How to Perform a Testicular Self-Examination Varicocele Male Reproductive System Testicular Torsion Contact Us Print Resources Send to ...

  14. Torsion-Mediated Interaction between Adjacent Genes

    PubMed Central

    Meyer, Sam; Beslon, Guillaume

    2014-01-01

    DNA torsional stress is generated by virtually all biomolecular processes involving the double helix, in particular transcription where a significant level of stress propagates over several kilobases. If another promoter is located in this range, this stress may strongly modify its opening properties, and hence facilitate or hinder its transcription. This mechanism implies that transcribed genes distant of a few kilobases are not independent, but coupled by torsional stress, an effect for which we propose the first quantitative and systematic model. In contrast to previously proposed mechanisms of transcriptional interference, the suggested coupling is not mediated by the transcription machineries, but results from the universal mechanical features of the double-helix. The model shows that the effect likely affects prokaryotes as well as eukaryotes, but with different consequences owing to their different basal levels of torsion. It also depends crucially on the relative orientation of the genes, enhancing the expression of eukaryotic divergent pairs while reducing that of prokaryotic convergent ones. To test the in vivo influence of the torsional coupling, we analyze the expression of isolated gene pairs in the Drosophila melanogaster genome. Their orientation and distance dependence is fully consistent with the model, suggesting that torsional gene coupling may constitute a widespread mechanism of (co)regulation in eukaryotes. PMID:25188032

  15. A fusional anomaly of the epididymis associated with recurrent testicular torsion.

    PubMed

    Aminu, Sani; Syed, Kamran; Gunendran, Thiru; Young, Graham

    2012-01-01

    A 31-year-old man with recurrent testicular torsion and infertility was found to have a fusional anomaly of the epididymis on scrotal exploration in which only the head of epididymis was attached to the testis, while the body and tail were completely free. He had bilateral orchidopexy, which relieved pain and recurrent torsion. He was then referred for fertility treatment. Literature search has shown that infertility is more associated with congenital anomalies of the epididymis and not with recurrent torsions. PMID:24578928

  16. Penile degloving and dorsal dartos flap rotation approach for the management of isolated penile torsion

    PubMed Central

    Aykaç, Aykut; Baran, Özer; Yapıcı, Onur; Aygün, Bülent Alper; Aydın, Cemil; Çakan, Murat

    2016-01-01

    Objective Penile torsion is a counterclockwise rotational anomaly of the penile shaft or glans. We aimed to evaluate the outcomes of penile degloving and dorsal dartos flap rotation used for the repair of isolated penil torsion. Material and methods During evaluation of the patients admitted to our polyclinic for circumcision between January 2013-December 2014, 5 cases of isolated penile torsion were determined. Following the circumcision procedure performed with bipolar cautery, patients undergoing penile degloving were checked whether penile torsion was relieved or not. In case of insufficient improvement, torsion was corrected with application of dorsal dartos flap. Penile torsion was corrected with dartos flap in 2, and penile degloving in 3 cases. Results The mean age of the patients was 5.6 years (4–7), and the mean operative time 12 minutes (7–20), respectively. The mean operation time was 17.5 (15–20) minutes and 8.3 (7–10) minutes in the dorsal dartos flap and penile degloving groups, respectively. The preoperative mean degree of penile torsion was 50° (30°–70°). The mean degree of torsion was 65° and 40° in the dorsal dartos and penile degloving groups, respectively. During the postoperative follow up, 1 case of residual torsion (<10°) was observed in the dorsal dartos flap group. Residual torsion was not observed in other patients. Conclusion Exploration for isolated cases of penile torsion during the circumcision procedure should not be overlooked. Successful results can be obtained with penile degloving and dartos flap rotation in cases with low and moderate torsion. PMID:27011878

  17. Planar torsion spring

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Parsons, Adam H. (Inventor); Mehling, Joshua S. (Inventor); Griffith, Bryan Kristian (Inventor)

    2012-01-01

    A torsion spring comprises an inner mounting segment. An outer mounting segment is located concentrically around the inner mounting segment. A plurality of splines extends from the inner mounting segment to the outer mounting segment. At least a portion of each spline extends generally annularly around the inner mounting segment.

  18. Topical Pain Relievers May Cause Burns

    MedlinePlus

    ... For Consumers Home For Consumers Consumer Updates Topical Pain Relievers May Cause Burns Share Tweet Linkedin Pin it ... ts If you've ever rubbed a topical pain reliever—a cream, gel or other product applied to ...

  19. Femtosecond torsional relaxation

    NASA Astrophysics Data System (ADS)

    Clark, J.; Nelson, T.; Tretiak, S.; Cirmi, G.; Lanzani, G.

    2012-03-01

    Molecular conformational reorganization following photon absorption is a fundamental process driving reactions such as the cis-trans isomerization at the heart of the primary step of vision and can be exploited for switching in artificial systems using photochromics. In general, conformational change occurs on a timescale defined by the energy of the main vibrational mode and the rate of energy dissipation. Typically, for a conformational change such as a twist around the backbone of a conjugated molecule, this occurs on the tens of picoseconds timescale. However, here we demonstrate experimentally that in certain circumstances the molecule, in this case an oligofluorene, can change conformation over two orders of magnitude faster (that is sub-100fs) in a manner analogous to inertial solvent reorganization demonstrated in the 1990s. Theoretical simulations demonstrate that non-adiabatic transitions during internal conversion can efficiently convert electronic potential energy into torsional kinetic energy, providing the `kick' that prompts sub-100fs torsional reorganization.

  20. Nonlinear Hysteretic Torsional Waves.

    PubMed

    Cabaret, J; Béquin, P; Theocharis, G; Andreev, V; Gusev, V E; Tournat, V

    2015-07-31

    We theoretically study and experimentally report the propagation of nonlinear hysteretic torsional pulses in a vertical granular chain made of cm-scale, self-hanged magnetic beads. As predicted by contact mechanics, the torsional coupling between two beads is found to be nonlinear hysteretic. This results in a nonlinear pulse distortion essentially different from the distortion predicted by classical nonlinearities and in a complex dynamic response depending on the history of the wave particle angular velocity. Both are consistent with the predictions of purely hysteretic nonlinear elasticity and the Preisach-Mayergoyz hysteresis model, providing the opportunity to study the phenomenon of nonlinear dynamic hysteresis in the absence of other types of material nonlinearities. The proposed configuration reveals a plethora of interesting phenomena including giant amplitude-dependent attenuation, short-term memory, as well as dispersive properties. Thus, it could find interesting applications in nonlinear wave control devices such as strong amplitude-dependent filters. PMID:26274421

  1. Torsional Ratcheting Actuating System

    SciTech Connect

    BARNES,STEPHEN MATTHEW; MILLER,SAMUEL L.; RODGERS,M. STEVEN; BITSIE,FERNANDO

    2000-01-24

    A new type of surface micromachined ratcheting actuation system has been developed at the Microelectronics Development Laboratory at Sandia National Laboratories. The actuator uses a torsional electrostatic comb drive that is coupled to an external ring gear through a ratcheting scheme. The actuator can be operated with a single square wave, has minimal rubbing surfaces, maximizes comb finger density, and can be used for open-loop position control. The prototypes function as intended with a minimum demonstrated operating voltage of 18V. The equations of motion are developed for the torsional electrostatic comb drive. The resonant frequency, voltage vs. displacement and force delivery characteristics are predicted and compared with the fabricated device's performance.

  2. Nonlinear Hysteretic Torsional Waves

    NASA Astrophysics Data System (ADS)

    Cabaret, J.; Béquin, P.; Theocharis, G.; Andreev, V.; Gusev, V. E.; Tournat, V.

    2015-07-01

    We theoretically study and experimentally report the propagation of nonlinear hysteretic torsional pulses in a vertical granular chain made of cm-scale, self-hanged magnetic beads. As predicted by contact mechanics, the torsional coupling between two beads is found to be nonlinear hysteretic. This results in a nonlinear pulse distortion essentially different from the distortion predicted by classical nonlinearities and in a complex dynamic response depending on the history of the wave particle angular velocity. Both are consistent with the predictions of purely hysteretic nonlinear elasticity and the Preisach-Mayergoyz hysteresis model, providing the opportunity to study the phenomenon of nonlinear dynamic hysteresis in the absence of other types of material nonlinearities. The proposed configuration reveals a plethora of interesting phenomena including giant amplitude-dependent attenuation, short-term memory, as well as dispersive properties. Thus, it could find interesting applications in nonlinear wave control devices such as strong amplitude-dependent filters.

  3. Pedicle torsion of ovarian cyst and acupuncture--a case report.

    PubMed

    Qu, Fan; Zhou, Jue

    2006-09-01

    A case history is reported of a patient who presented with acute pedicle torsion in a left ovarian cyst, which had been diagnosed seven months previously. The diagnosis was established by sonography. She declined surgery for personal reasons, and was treated with acupuncture. Her pain was successfully relieved, and she continued to be observed. The acupuncture was repeated daily for 15 days, after which time repeat sonography showed reduction in size of the cyst, and no torsion of the pedicle. No relapse had occurred at 16 months follow up. PMID:17013361

  4. [Development of cough-relieving herbal teas].

    PubMed

    Puodziūniene, Gene; Janulis, Valdimaras; Milasius, Arvydas; Budnikas, Vytautas

    2005-01-01

    Cough-relieving medicinal herbs in tea are used from ancient times. Mucilage present in them or secretion produced under the influence of the active substances covers the oral and throat mucosa soothing its irritability and relieving dry, tiresome cough. It is known that the mixtures of medicinal herbs (Specias) have a complex influence on the human organism and the rational combination of medicinal herbs can improve their curative action and decrease the undesirable side effects. Having summarized the properties of those medicinal herbs we decided to create two formulations of cough-relieving herbal tea. The first formulation consists of marshmallow roots, liquorice roots and lime flowers, the second -- of marshmallow roots, Iceland moss and lime flowers. The methods for identification and assay of the active substances in the compounds were applied. The purity of the mixtures was regulated by limitation of the loss on drying, total ash, microbial contamination, contamination with radionuclides, heavy metals, pesticides and foreign matter. The expiry date of both cough-relieving herbal teas was approved to be 2 years. PMID:15998989

  5. Jacketed cryogenic piping is stress relieved

    NASA Technical Reports Server (NTRS)

    Bowers, W. M.

    1967-01-01

    Jacketed design of piping used to transfer cryogenic fluids, relieves severe stresses associated with the temperature gradients that occur during transfer cycles and ambient periods. The inner /transfer/ pipe is preloaded in such a way that stress relief takes place automatically as cycling occurs.

  6. Testicular torsion: A surgical emergency

    SciTech Connect

    Prater, J.M.; Overdorf, B.S. )

    1991-09-01

    Testicular torsion is caused by twisting of the spermatic cord, which results in compromised testicular blood flow. The degree of ischemic injury is determined by the severity of arterial compression and the interval between the onset of symptoms and surgical intervention. Torsion usually occurs at puberty, and an anatomic defect known as bell-clapper deformity is usually present. Typical symptoms include acute scrotal pain with associated nausea and vomiting. Up to one-half of patients report previous similar episodes. On examination, the testis is high-riding, tender, swollen and firm. Testicular scan or Doppler ultrasound examination can be helpful in distinguishing torsion from acute epididymitis. Prompt surgical treatment is indicated to reduce the torsion, and bilateral orchiopexy is performed to prevent recurrence. Exocrine function, as determined by semen analysis, is often abnormal after unilateral torsion. 25 references.

  7. Torsional sensing of small-molecule binding using magnetic tweezers.

    PubMed

    Lipfert, Jan; Klijnhout, Sven; Dekker, Nynke H

    2010-11-01

    DNA-binding small molecules are widespread in the cell and heavily used in biological applications. Here, we use magnetic tweezers, which control the force and torque applied to single DNAs, to study three small molecules: ethidium bromide (EtBr), a well-known intercalator; netropsin, a minor-groove binding anti-microbial drug; and topotecan, a clinically used anti-tumor drug. In the low-force limit in which biologically relevant torques can be accessed (<10 pN), we show that ethidium intercalation lengthens DNA ∼1.5-fold and decreases the persistence length, from which we extract binding constants. Using our control of supercoiling, we measure the decrease in DNA twist per intercalation to be 27.3±1° and demonstrate that ethidium binding delays the accumulation of torsional stress in DNA, likely via direct reduction of the torsional modulus and torque-dependent binding. Furthermore, we observe that EtBr stabilizes the DNA duplex in regimes where bare DNA undergoes structural transitions. In contrast, minor groove binding by netropsin affects neither the contour nor persistence length significantly, yet increases the twist per base of DNA. Finally, we show that topotecan binding has consequences similar to those of EtBr, providing evidence for an intercalative binding mode. These insights into the torsional consequences of ligand binding can help elucidate the effects of small-molecule drugs in the cellular environment. PMID:20624816

  8. Torsion Tests of Tubes

    NASA Technical Reports Server (NTRS)

    Stang, Ambrose H; Ramberg, Walter; Back, Goldie

    1937-01-01

    This report presents the results of tests of 63 chromium-molybdenum steel tubes and 102 17st aluminum-alloy tubes of various sizes and lengths made to study the dependence of the torsional strength on both the dimensions of the tube and the physical properties of the tube material. Three types of failure are found to be important for sizes of tubes frequently used in aircraft construction: (1) failure by plastic shear, in which the tube material reached its yield strength before the critical torque was reached; (2) failure by elastic two-lobe buckling, which depended only on the elastic properties of the tube material and the dimensions of the tube; and (3) failure by a combination of (1) and (2) that is, by buckling taking place after some yielding of the tube material.

  9. Saccular impact on ocular torsion.

    PubMed

    De Graaf, B; Bos, J E; Groen, E

    1996-01-01

    When someone is tilted laterally, the shear force on the maculae of the utriculus and the sacculus is described by the sine and the cosine of the angle of tilt, respectively. So both the sacculus and the utriculus are stimulated, but in the literature, ocular torsion is normally attributed to utricular function alone (and, thus, seen as a response to y-axis linear acceleration). However, on the base of a series of experiments on a tilt chair, a linear track, human centrifuges, and during parabolic flights, we conclude that the sacculus contributes to ocular torsion as well (there is a response to z-axis linear acceleration). The data suggest that the ratio of the utricular and saccular impact on ocular torsion is 3:1. The utriculus generates conjugate and the sacculus disjunctive torsional eye movements. PMID:8886354

  10. Isolated penile torsion in newborns

    PubMed Central

    Eroglu, Egemen; Gundogdu, Gokhan

    2015-01-01

    Introduction: We reported on the incidence of isolated penile torsion among our healthy children and our approach to this anomaly. Methods: Between 2011 and 2014, newborn babies with penile torsion were classified according to the angle of torsion. Surgical correction (penile degloving and reattachment for moderate cases and dorsal dartos flap technique in case of resistance) after 6 months was advised to the babies with rotations more than 45°. Results: Among 1000 newborn babies, 200 isolated penile torsions were found, and among these, 43 had torsions more than 45°, and 4 of these had angles greater than 90°. The mean angle of the rotations was found 30.45° (median: 20°). In total, 8 children with 60° torsions were previously circumcised. Surgery was performed on 19 patients, with a mean patient age of 12 ± 2 months. Of these 19, 13 babies were corrected with degloving and reattachment. This technique was not enough on the remaining 6 patients; therefore, derotational dorsal dartos flap was added to correct the torsion. After a mean of 15.6 ± 9.8 months, residual penile rotation, less than 15°, was found only in 2 children. Conclusion: The incidence of isolated penile torsion is 20% in newborns. However, rotation more than 45° angles are seen in 4.3% of male babies. Correction is not necessary in mild degrees, and penile degloving with reattachment is enough in most cases. If the initial correction is insufficient, dorsal dartos flap rotation is easy and effective. Prior circumcision neither disturbs the operative procedure nor affects the outcomes. PMID:26600889

  11. Torsional vibration of aircraft engines

    NASA Technical Reports Server (NTRS)

    Lurenbaum, Karl

    1932-01-01

    Exhaustive torsional-vibration investigations are required to determine the reliability of aircraft engines. A general outline of the methods used for such investigations and of the theoretical and mechanical means now available for this purpose is given, illustrated by example. True vibration diagrams are usually obtained from vibration measurements on the completed engine. Two devices for this purpose and supplementing each other, the D.V.L. torsiograph and the D.V.L. torsion recorder, are described in this report.

  12. Hand-held instrument should relieve hematoma pressure

    NASA Technical Reports Server (NTRS)

    Raggio, L. J.; Robertson, T. L.

    1967-01-01

    Portable instrument relieves hematomas beneath fingernails and toenails without surgery. This device simplifies the operative procedure with an instant variable heating tip, adjustable depth settings and interchangeable tip sizes for cauterizing small areas and relieving pressurized clots.

  13. The Effect of Torsion-Torsion Interactions on the Tunneling Split Torsional Ground State.

    NASA Astrophysics Data System (ADS)

    Cameron, Ian George

    In NMR studies of methyl groups it is normally assumed that the effects of inter-methyl group interactions (torsion-torsion interactions) are negligible. This is probably a reasonable assump- tion at high temperatures(, )(>50K), however, for lower temperatures this is no longer the case. This is clearly demonstrated with tetra- methylsilane (TMS) for which several important effects of torsion-torsion interactions are reported. The spin lattice relaxtion time, T(,1), was measured as a function of the Larmor frequency at several temperatures and it is shown that the observed recovery can be characterized by two exponential contributions. As anticipated, the frequency dependence of T(,ZT)('-1), the recovery rate for the faster of the two contributing processes, exhibited resonant-like peaks. In other ways, however, these results deviate quite substantially from the behavior expected. Firstly, the hindering potential experienced by each methyl group in TMS is perturbed by the other three methyl groups in the molecule. This leads to the appearance of four resonant peaks in the frequency dependence of T(,ZT)('-1) instead of just two. A perturbation calculation is presented to support this interpretation. Secondly, the contribu- tion to the measured linewidths from lifetime broadening, which dominates at high temperatures, becomes negligible at low tem- peratures compared with the underlying "inherent" width of the tunneling lines. We associate this inherent width with a relatively narrow ((TURN)1 MHz), quasi-continuous distribution of tunneling split- tings which occurs as a result of partially averaged torsion-torsion interactions. Thirdly, the intensity of the peaks, which is expected to be temperature independent, drops sharply as the temperature is lowered. This is a clear indication of the formation of a band of tunneling states of low temperatures where torsion-torsion interactions are strong.

  14. Hypersymplectic structures with torsion on Lie algebroids

    NASA Astrophysics Data System (ADS)

    Antunes, P.; Nunes da Costa, J. M.

    2016-06-01

    Hypersymplectic structures with torsion on Lie algebroids are investigated. We show that each hypersymplectic structure with torsion on a Lie algebroid determines three Nijenhuis morphisms. From a contravariant point of view, these structures are twisted Poisson structures. We prove the existence of a one-to-one correspondence between hypersymplectic structures with torsion and hyperkähler structures with torsion. We show that given a Lie algebroid with a hypersymplectic structure with torsion, the deformation of the Lie algebroid structure by any of the transition morphisms does not affect the hypersymplectic structure with torsion. We also show that if a triplet of 2-forms is a hypersymplectic structure with torsion on a Lie algebroid A, then the triplet of the inverse bivectors is a hypersymplectic structure with torsion for a certain Lie algebroid structure on the dual A∗, and conversely. Examples of hypersymplectic structures with torsion are included.

  15. Stress-relieving interlayers for bituminous resurfacings

    NASA Astrophysics Data System (ADS)

    Frederick, D. A.

    1984-04-01

    The effectiveness of stress relieving interlayers (SRIs) in reducing reflective cracking in bituminous overlays on flexible pavements was investigated. SRI test sections were installed in 1980 and 1981 at five locations comprised of both 1 and 2-1/2 in overlays. Before construction, cracks were mapped in detail and deflection was measured to determine causes of cracking. SRIs tested included full width nonwoven and woven fabrics, rubberized asphalt surface treatments, reinforced rubberized asphalt strips, and composite fiberglass-asphalt binder systems. Construction of these test installations is summarized. Results of annual surveys have yet to prove conclusively the value of using these materials or their comparative effectiveness.

  16. Torsion Stiffness of a Protein Pair Determined by Magnetic Particles

    PubMed Central

    Janssen, X.J.A.; van Noorloos, J.M.; Jacob, A.; van IJzendoorn, L.J.; de Jong, A.M.; Prins, M.W.J.

    2011-01-01

    We demonstrate the ability to measure torsion stiffness of a protein complex by applying a controlled torque on a magnetic particle. As a model system we use protein G bound to an IgG antibody. The protein pair is held between a magnetic particle and a polystyrene substrate. The angular orientation of the magnetic particle shows an oscillating behavior upon application of a rotating magnetic field. The amplitude of the oscillation increases with a decreasing surface coverage of antibodies on the substrate and with an increasing magnitude of the applied field. For decreasing antibody coverage, the torsion spring constant converges to a minimum value of 1.5 × 103 pN·nm/rad that corresponds to a torsion modulus of 4.5 × 104 pN·nm2. This torsion stiffness is an upper limit for the molecular bond between the particle and the surface that is tentatively assigned to a single protein G–IgG protein pair. This assignment is supported by interpreting the measured stiffness with a simple mechanical model that predicts a two orders of magnitude larger stiffness for the protein G–IgG complex than values found for micrometer length dsDNA. This we understand from the structural properties of the molecules, i.e., DNA is a long and flexible chain-like molecule, whereas the antibody-antigen couple is orders of magnitude smaller and more globular in shape due to the folding of the molecules. PMID:21539795

  17. Propagating torsion in the Einstein frame

    SciTech Connect

    Poplawski, Nikodem J.

    2006-11-15

    The Einstein-Cartan-Saa theory of torsion modifies the spacetime volume element so that it is compatible with the connection. The condition of connection compatibility gives constraints on torsion, which are also necessary for the consistence of torsion, minimal coupling, and electromagnetic gauge invariance. To solve the problem of positivity of energy associated with the torsionic scalar, we reformulate this theory in the Einstein conformal frame. In the presence of the electromagnetic field, we obtain the Hojman-Rosenbaum-Ryan-Shepley theory of propagating torsion with a different factor in the torsionic kinetic term.

  18. Constraining torsion with Gravity Probe B

    SciTech Connect

    Mao Yi; Guth, Alan H.; Cabi, Serkan; Tegmark, Max

    2007-11-15

    It is well-entrenched folklore that all torsion gravity theories predict observationally negligible torsion in the solar system, since torsion (if it exists) couples only to the intrinsic spin of elementary particles, not to rotational angular momentum. We argue that this assumption has a logical loophole which can and should be tested experimentally, and consider nonstandard torsion theories in which torsion can be generated by macroscopic rotating objects. In the spirit of action=reaction, if a rotating mass like a planet can generate torsion, then a gyroscope would be expected to feel torsion. An experiment with a gyroscope (without nuclear spin) such as Gravity Probe B (GPB) can test theories where this is the case. Using symmetry arguments, we show that to lowest order, any torsion field around a uniformly rotating spherical mass is determined by seven dimensionless parameters. These parameters effectively generalize the parametrized post-Newtonian formalism and provide a concrete framework for further testing Einstein's general theory of relativity (GR). We construct a parametrized Lagrangian that includes both standard torsion-free GR and Hayashi-Shirafuji maximal torsion gravity as special cases. We demonstrate that classic solar system tests rule out the latter and constrain two observable parameters. We show that Gravity Probe B is an ideal experiment for further constraining nonstandard torsion theories, and work out the most general torsion-induced precession of its gyroscope in terms of our torsion parameters.

  19. Constraining torsion with Gravity Probe B

    NASA Astrophysics Data System (ADS)

    Mao, Yi; Tegmark, Max; Guth, Alan H.; Cabi, Serkan

    2007-11-01

    It is well-entrenched folklore that all torsion gravity theories predict observationally negligible torsion in the solar system, since torsion (if it exists) couples only to the intrinsic spin of elementary particles, not to rotational angular momentum. We argue that this assumption has a logical loophole which can and should be tested experimentally, and consider nonstandard torsion theories in which torsion can be generated by macroscopic rotating objects. In the spirit of action=reaction, if a rotating mass like a planet can generate torsion, then a gyroscope would be expected to feel torsion. An experiment with a gyroscope (without nuclear spin) such as Gravity Probe B (GPB) can test theories where this is the case. Using symmetry arguments, we show that to lowest order, any torsion field around a uniformly rotating spherical mass is determined by seven dimensionless parameters. These parameters effectively generalize the parametrized post-Newtonian formalism and provide a concrete framework for further testing Einstein’s general theory of relativity (GR). We construct a parametrized Lagrangian that includes both standard torsion-free GR and Hayashi-Shirafuji maximal torsion gravity as special cases. We demonstrate that classic solar system tests rule out the latter and constrain two observable parameters. We show that Gravity Probe B is an ideal experiment for further constraining nonstandard torsion theories, and work out the most general torsion-induced precession of its gyroscope in terms of our torsion parameters.

  20. Torsional vibration isolator and method

    SciTech Connect

    Allen, C.A.; Durrett, V.D.

    1986-10-21

    This patent describes a multicylinder internal combustion engine having a rotatable crankshaft and a rotatable flywheel which together define an inertial system rotating about a predetermined axis of rotation. An improvement is described here which facilitates avoiding destructive effects on the crankshaft of stress induced by torsional vibration. The method comprises an elastomeric annulus coupling means operatively interposed between the crankshaft and flywheel for coupling the crankshaft and flywheel together for rotation of the flywheel with the crankshaft. The coupling means has a torsional spring rate of less than 20,000 in lb/radian effective to permit substantial angular displacement between the flywheel and the crankshaft for isolating the rotating inertia of the flywheel from the rotating inertia of the crankshaft after engine startup. The coupling means avoids dampening while preventing torsional vibration from being transferred between the flywheel and the crankshaft.

  1. Torsional Carbon Nanotube Artificial Muscles

    NASA Astrophysics Data System (ADS)

    Foroughi, Javad; Spinks, Geoffrey M.; Wallace, Gordon G.; Oh, Jiyoung; Kozlov, Mikhail E.; Fang, Shaoli; Mirfakhrai, Tissaphern; Madden, John D. W.; Shin, Min Kyoon; Kim, Seon Jeong; Baughman, Ray H.

    2011-10-01

    Rotary motors of conventional design can be rather complex and are therefore difficult to miniaturize; previous carbon nanotube artificial muscles provide contraction and bending, but not rotation. We show that an electrolyte-filled twist-spun carbon nanotube yarn, much thinner than a human hair, functions as a torsional artificial muscle in a simple three-electrode electrochemical system, providing a reversible 15,000° rotation and 590 revolutions per minute. A hydrostatic actuation mechanism, as seen in muscular hydrostats in nature, explains the simultaneous occurrence of lengthwise contraction and torsional rotation during the yarn volume increase caused by electrochemical double-layer charge injection. The use of a torsional yarn muscle as a mixer for a fluidic chip is demonstrated.

  2. Imaging soft matters in water with torsional mode atomic force microscopy.

    PubMed

    Hwang, Ing-Shouh; Yang, Chih-Wen; Su, Ping-Hsiang; Hwu, En-Te; Liao, Hsien-Shun

    2013-12-01

    We have developed a high-sensitivity atomic force microscopy (AFM) mode operated in aqueous environment based on the torsional resonance of the cantilever. It is found that the torsional mode can achieve a good spatial resolution even with a relatively large tip. We have used this mode to image different soft materials in water, including DNA molecules and purple membrane. High-resolution images of purple membrane can be obtained at a relatively low ion concentration under a long-range electrostatic force. Thus the torsional mode allows investigators to probe surface structures and their properties under a wide range of solution conditions. PMID:22939703

  3. Flexural Torsional Guided Wave Pipe Inspection

    NASA Astrophysics Data System (ADS)

    Sun, Z.; Zhang, L.; Rose, J. L.

    2006-03-01

    Based on the flexural torsional guided wave theory and its focusing technique, this paper demonstrates the defect detection capability of flexural torsional guided waves on multiple defects with different shapes and axial, circumferential locations in pipe.

  4. Can a macroscopic gyroscope feel torsion

    NASA Technical Reports Server (NTRS)

    Stoeger, W. R.; Yasskin, P. B.

    1979-01-01

    We demonstrate that for a large class of Lagrangian-based torsion theories a macroscopic gyroscope is insensitive to the torsion field: there can be no coupling of the torsion to the gyroscope's angular momentum of rotation. To detect torsion a polarized system with a net elementary particle spin is needed. These conclusions are evident from the conservation laws, which form the basis for deriving the equations of motion.

  5. Torsion and buckling of open sections

    NASA Technical Reports Server (NTRS)

    Wagner, H; Pretschner, W

    1936-01-01

    Following an abstract of the well-known theory of torsion in compression, the writers give directions for the practical calculation of the values of C(sub BT) (resistance to flexure and torsion) and i(sub SP(exp 2)), which determine the torsion. The second part treats the experiments in support of the theory of torsion of plain and flanged angle sections.

  6. Torsional directed walks, entropic elasticity, and DNA twist stiffness

    PubMed Central

    Moroz, J. David; Nelson, Philip

    1997-01-01

    DNA and other biopolymers differ from classical polymers because of their torsional stiffness. This property changes the statistical character of their conformations under tension from a classical random walk to a problem we call the “torsional directed walk.” Motivated by a recent experiment on single lambda-DNA molecules [Strick, T. R., Allemand, J.-F., Bensimon, D., Bensimon, A. & Croquette, V. (1996) Science 271, 1835–1837], we formulate the torsional directed walk problem and solve it analytically in the appropriate force regime. Our technique affords a direct physical determination of the microscopic twist stiffness C and twist-stretch coupling D relevant for DNA functionality. The theory quantitatively fits existing experimental data for relative extension as a function of overtwist over a wide range of applied force; fitting to the experimental data yields the numerical values C = 120 nm and D = 50 nm. Future experiments will refine these values. We also predict that the phenomenon of reduction of effective twist stiffness by bend fluctuations should be testable in future single-molecule experiments, and we give its analytic form. PMID:9405627

  7. The torsional and rotation-torsion spectra of CD2HOH

    NASA Astrophysics Data System (ADS)

    Ndao, M.; Kwabia Tchana, F.; Coudert, L. H.; Motiyenko, R. A.; Margulès, L.; Barros, J.; Manceron, L.; Roy, P.

    2016-08-01

    The torsional and rotation-torsion spectra of the doubly deuterated species of methanol CD2HOH have been analyzed using submillimeter wave, terahertz, and far infrared spectra. 101 torsional subbands, with subband centers ranging from 2.3 to 626 cm-1, were assigned. Analysis of these yielded kinetic energy and hindering potential parameters of the torsional Hamiltonian describing the large amplitude internal rotation of the CD2H methyl group with respect to the hydroxyl group. 3271 rotation and rotation-torsion transitions, involving the 24 torsional levels up to e1 with 3 ⩽ K ⩽ 10 , were assigned and fitted approximating the rotational energy of each torsional level with a Taylor-type expansion in J (J + 1) . The rotational structure of 48 torsional subbands involving torsional levels higher than e1 has also been analyzed. In most cases, only the Q branch could be observed and assigned.

  8. 46 CFR 58.20-10 - Pressure relieving devices.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Pressure relieving devices. 58.20-10 Section 58.20-10... MACHINERY AND RELATED SYSTEMS Refrigeration Machinery § 58.20-10 Pressure relieving devices. (a) Each pressure vessel containing refrigerants, which may be isolated, shall be protected by a relief valve set...

  9. 46 CFR 58.20-10 - Pressure relieving devices.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Pressure relieving devices. 58.20-10 Section 58.20-10... MACHINERY AND RELATED SYSTEMS Refrigeration Machinery § 58.20-10 Pressure relieving devices. (a) Each pressure vessel containing refrigerants, which may be isolated, shall be protected by a relief valve set...

  10. 46 CFR 58.20-10 - Pressure relieving devices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Pressure relieving devices. 58.20-10 Section 58.20-10... MACHINERY AND RELATED SYSTEMS Refrigeration Machinery § 58.20-10 Pressure relieving devices. (a) Each pressure vessel containing refrigerants, which may be isolated, shall be protected by a relief valve set...

  11. 46 CFR 58.20-10 - Pressure relieving devices.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Pressure relieving devices. 58.20-10 Section 58.20-10... MACHINERY AND RELATED SYSTEMS Refrigeration Machinery § 58.20-10 Pressure relieving devices. (a) Each pressure vessel containing refrigerants, which may be isolated, shall be protected by a relief valve set...

  12. 46 CFR 58.20-10 - Pressure relieving devices.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Pressure relieving devices. 58.20-10 Section 58.20-10... MACHINERY AND RELATED SYSTEMS Refrigeration Machinery § 58.20-10 Pressure relieving devices. (a) Each pressure vessel containing refrigerants, which may be isolated, shall be protected by a relief valve set...

  13. Depletion of intracellular polyamines relieves inward rectification of potassium channels.

    PubMed Central

    Shyng, S L; Sha, Q; Ferrigni, T; Lopatin, A N; Nichols, C G

    1996-01-01

    Two different approaches were used to examine the in vivo role of polyamines in causing inward rectification of potassium channels. In two-microelectrode voltage-clamp experiments, 24-hr incubation of Xenopus oocytes injected with 50 nl of difluoromethylornithine (5 mM) and methylglyoxal bis(guanylhydrazone) (1 mM) caused an approximate doubling of expressed Kir2.1 currents and relieved rectification by causing an approximately +10-mV shift of the voltage at which currents are half-maximally inhibited. Second, a putrescine auxotrophic, ornithine decarboxylase-deficient Chinese hamster ovary (O-CHO) cell line was stably transfected with the cDNA encoding Kir2.3. Withdrawal of putrescine from the medium led to rapid (1-day) loss of the instantaneous phase of Kir2.3 channel activation, consistent with a decline of intracellular putrescine levels. Four days after putrescine withdrawal, macroscopic conductance, assessed using an 86Rb+ flux assay, was approximately doubled, and this corresponded to a +30-mV shift of V1/2 of rectification. With increasing time after putrescine withdrawal, there was an increase in the slowest phase of current activation, corresponding to an increase in the spermine-to-spermidine ratio over time. These results provide direct evidence for a role of each polyamine in induction of rectification, and they further demonstrate that in vivo modulation of rectification is possible by manipulation of polyamine levels using genetic and pharmacological approaches. PMID:8876254

  14. Re-torsion of the ovaries.

    PubMed

    Hyttel, Trine E W; Bak, Geske S; Larsen, Solveig B; Løkkegaard, Ellen C L

    2015-03-01

    The increasing use of de-torsion of the ovaries may result in re-torsion. This review addresses risk of re-torsion and describes preventive strategies to avoid re-torsion in pre-menarcheal girls, and fertile and pregnant women. We clinically reviewed PubMed, Embase, Trip and Cochrane databases. The main outcome measures were re-torsion and viability of ovary with fixation measures. A total of 38 publications including 71 girls, 363 fertile women, and 69 pregnant women were found to be relevant. All studies were case reports or case series, sometimes with non-randomized controls. The studies show considerable heterogeneity in design, population, management and outcome. Only four studies included more than 50 cases. In pregnancy the risk of re-torsion was as high as 19.5-37.5%; among fertile women it was 28.6%. Most articles concluded that fixation of the ovaries to the pelvic sidewall or plication of the ovarian ligament after torsion may prevent re-torsion. In one case a girl experienced re-torsion after ovariopexy. Based on observational studies it seems that de-torsion and fixation of the ovary is a safe procedure that usually ensures maintenance of ovarian function and reduces the risk of recurrence, especially when there are no ovarian cysts or adnexal masses. PMID:25412114

  15. Topological design of torsional metamaterials

    NASA Astrophysics Data System (ADS)

    Vitelli, Vincenzo; Paulose, Jayson; Meeussen, Anne; Topological Mechanics Lab Team

    Frameworks - stiff elements with freely hinged joints - model the mechanics of a wide range of natural and artificial structures, including mechanical metamaterials with auxetic and topological properties. The unusual properties of the structure depend crucially on the balance between degrees of freedom associated with the nodes, and the constraints imposed upon them by the connecting elements. Whereas networks of featureless nodes connected by central-force springs have been well-studied, many real-world systems such as frictional granular packings, gear assemblies, and flexible beam meshes incorporate torsional degrees of freedom on the nodes, coupled together with transverse shear forces exerted by the connecting elements. We study the consequences of such torsional constraints on the mechanics of periodic isostatic networks as a foundation for mechanical metamaterials. We demonstrate the existence of soft modes of topological origin, that are protected against disorder or small perturbations of the structure analogously to their counterparts in electronic topological insulators. We have built a lattice of gears connected by rigid beams that provides a real-world demonstration of a torsional metamaterial with topological edge modes and mechanical Weyl modes.

  16. Cosmology in Poincaré gauge gravity with a pseudoscalar torsion

    NASA Astrophysics Data System (ADS)

    Lu, Jianbo; Chee, Guoying

    2016-05-01

    A cosmology of Poincar é gauge theory is developed, where several properties of universe corresponding to the cosmological equations with the pseudoscalar torsion function are investigated. The cosmological constant is found to be the intrinsic torsion and curvature of the vacuum universe and is derived from the theory naturally rather than added artificially, i.e. the dark energy originates from geometry and includes the cosmological constant but differs from it. The cosmological constant puzzle, the coincidence and fine tuning problem are relieved naturally at the same time. By solving the cosmological equations, the analytic cosmological solution is obtained and can be compared with the ΛCDM model. In addition, the expressions of density parameters of the matter and the geometric dark energy are derived, and it is shown that the evolution of state equations for the geometric dark energy agrees with the current observational data. At last, the full equations of linear cosmological perturbations and the solutions are obtained.

  17. An analysis of traction drive torsional stiffness

    NASA Technical Reports Server (NTRS)

    Rohn, D. A.; Loewenthal, S. H.

    1983-01-01

    The tangential compliance of elastic bodies in concentrated contact applied to traction drive elements to determine their torsional stiffness was analyzed. Static loading and rotating conditions are considered. The effects of several design variables are shown. The theoretical torsional stiffness of a fixed ratio multiroller drive is computed and compared to experimental values. It is shown that the torsional compliance of the traction contacts themselves is a relatively small portion of the overall drive system compliance.

  18. Empirical formula of crustal torsional oscillations

    NASA Astrophysics Data System (ADS)

    Sotani, Hajime

    2016-02-01

    Crustal torsional oscillations depend on not only crust properties but also the stellar mass and radius. Thus, one could extract stellar information by identifying the observed frequencies of stellar oscillations with the crustal torsional oscillations. Owing to the confinement of torsional oscillations inside the crust region of neutron stars, we successfully derive an empirical formula for the fundamental crustal torsional oscillations as a function of the stellar mass, radius, the so-called slope parameter of the nuclear symmetry energy, and the angular index of oscillations, with which one can estimate the frequencies with high accuracy. This empirical formula could be valuable in both the astrophysics and nuclear physics communities.

  19. Review Suggests Safe, Effective Ways to Relieve Pain Without Meds

    MedlinePlus

    ... page: https://medlineplus.gov/news/fullstory_160744.html Review Suggests Safe, Effective Ways to Relieve Pain Without ... appear to be effective, according to a new review. Millions of Americans seek pain relief through such ...

  20. Cellar: Detail of paired relieving arch and remains of herringbone ...

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

    Cellar: Detail of paired relieving arch and remains of herringbone brick pattern from earlier cooking fireplace at back, southeast wall looking southeast - Kingston-Upon-Hill, Kitts Hummock Road, Dover, Kent County, DE

  1. Halfcellar underneath original house showing fireplace relieving arch at northwest ...

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

    Half-cellar underneath original house showing fireplace relieving arch at northwest end; enclosed "cheese" room to right - Scheetz Farm, House, 7161 Camp Hill Road, Fort Washington, Montgomery County, PA

  2. Reviewing the Literature on the Effectiveness of Pressure Relieving Movements

    PubMed Central

    Stinson, May

    2013-01-01

    Sitting for prolonged periods of time increases seating interface pressures, which is known to increase the risk of developing pressure ulcers. Those at risk of developing pressure ulcers are advised to perform pressure relieving movements such as “pushups” or “forward leans” in order to reduce the duration and magnitude of pressure acting on the vulnerable ischial tuberosity region. The aim of this review was to synthesize and critique the existing literature investigating the effectiveness of pressure relieving movements on seating interface pressures. The twenty-seven articles included in this paper highlight the need for further research investigating the effect of recommended pressure relieving movements on the pressures around the ischial tuberosities. Furthermore, this review found that the majority of individuals at risk of developing pressure ulcers do not adhere with the pressure relieving frequency or magnitude of movements currently recommended, indicating a need for pressure ulcer prevention to be explored further. PMID:23365733

  3. Results of experimental tests in the MSFC 14 x 14 inch trisonic wind tunnel on a .004 scale model space shuttle integrated vehicle 5 (model 77-O, 74-TS) to relieve wing loads during ascent (IA71)

    NASA Technical Reports Server (NTRS)

    Allen, E. C.

    1975-01-01

    Results are presented for the 0.004-scale orbiter, external tank, and solid rocket boosters combined as an integrated vehicle in a trisonic wind tunnel at mach numbers from 0.6 to 2.0. The primary test objective was to determine the effectiveness of several methods in relieving the Orbiter wing bending and torsion loads and moments during launch. Effects of several midwing spoilers, termed flipper doors, and Orbiter/external tank incidence were investigated. Photographs are included.

  4. Torsion of Noncircular Composite Cylinders

    NASA Technical Reports Server (NTRS)

    Rouse, Marshall; Hyer, Michael W.; Haynie, Waddy T.

    2005-01-01

    The paper presents a brief overview of the predicted deformation and failure characteristics of noncircular composite cylinders subjected to torsion. Using a numerical analysis, elliptical cylinders with a minor-to-major diameter ratio of 0.7 are considered. Counterpart circular cylinders with the same circumference as the elliptical cylinders are included for comparison. The cylinders are constructed of a medium-modulus graphite-epoxy material in a quasi-isotropic lay-up. Imperfections generated from the buckling mode shapes are included in the initial cross-sectional geometry of the cylinders. Deformations until first fiber failure, as predicted using the maximum stress failure criterion and a material degradation scheme, are presented. For increasing levels of torsion, the deformations of the elliptical cylinders, in the form of wrinkling of the cylinder wall, occur primarily in the flatter regions of the cross section. By comparison the wrinkling deformations of the circular cylinders are more uniformly distributed around the circumference. Differences in the initial failure and damage progression and the overall torque vs. twist relationship between the elliptical and circular cylinders are presented. Despite differences in the response as the cylinders are being loaded, at first fiber failure the torque and twist for the elliptical and circular cylinders nearly coincide.

  5. Optically probing torsional superelasticity in spider silks

    NASA Astrophysics Data System (ADS)

    Kumar, Bhupesh; Thakur, Ashish; Panda, Biswajit; Singh, Kamal P.

    2013-11-01

    We investigate torsion mechanics of various spider silks using a sensitive optical technique. We find that spider silks are torsionally superelastic in that they can reversibly withstand great torsion strains of over 102-3 rotations per cm before failure. Among various silks from a spider, we find the failure twist-strain is greatest in the sticky capture silk followed by dragline and egg-case silk. Our in situ laser-diffraction measurements reveal that torsional strains on the silks induce a nano-scale transverse compression in its diameter that is linear and reversible. These unique torsional properties of the silks could find applications in silk-based materials and devices.

  6. Torsion Profiling of Proteins Using Magnetic Particles

    PubMed Central

    van Reenen, A.; Gutiérrez-Mejía, F.; van IJzendoorn, L.J.; Prins, M.W.J.

    2013-01-01

    We report a method to profile the torsional spring properties of proteins as a function of the angle of rotation. The torque is applied by superparamagnetic particles and has been calibrated while taking account of the magnetization dynamics of the particles. We record and compare the torsional profiles of single Protein G-Immunoglobulin G (IgG) and IgG-IgG complexes, sandwiched between a substrate and a superparamagnetic particle, for torques in the range between 0.5 × 103 and 5 × 103 pN·nm. Both molecular systems show torsional stiffening for increasing rotation angle, but the elastic and inelastic torsion stiffnesses are remarkably different. We interpret the results in terms of the structural properties of the molecules. The torsion profiling technique opens new dimensions for research on biomolecular characterization and for research on bio-nanomechanical structure-function relationships. PMID:23473490

  7. Optically probing torsional superelasticity in spider silks

    SciTech Connect

    Kumar, Bhupesh; Thakur, Ashish; Panda, Biswajit; Singh, Kamal P.

    2013-11-11

    We investigate torsion mechanics of various spider silks using a sensitive optical technique. We find that spider silks are torsionally superelastic in that they can reversibly withstand great torsion strains of over 10{sup 2−3} rotations per cm before failure. Among various silks from a spider, we find the failure twist-strain is greatest in the sticky capture silk followed by dragline and egg-case silk. Our in situ laser-diffraction measurements reveal that torsional strains on the silks induce a nano-scale transverse compression in its diameter that is linear and reversible. These unique torsional properties of the silks could find applications in silk-based materials and devices.

  8. Torsional fatigue of aramid fibers

    SciTech Connect

    Kawabata, S.; Sera, M.

    1993-12-31

    An experimental investigation on the shear fatigue process of aramid fibers is presented. Repeated cycles of the torsional deformation are applied on the aramid single fiber and the reduction of the shear modulus of the fiber with an increasing number of the cycles is observed for different strain amplitudes. It has been found that the reduction process of the shear modulus with an increasing number of the repeated cycles depends on the strain amplitude and the effect of the number of cycles is equivalent to that of the strain amplitude on the modulus reduction and they may be superposed like the time-temperature equivalence superposition observed in the viscoelasticity of amorphous polymeric solids. From this relation, the life prediction for the long term use of aramid fibers becomes possible by using this superimposed relation. A simple rate process theory is applied to interpret this fatigue process and to derive the equation for predicting the life cycle number of the loading.

  9. Magnetic Torsional Oscillations in Magnetars

    SciTech Connect

    Sotani, Hajime; Kokkotas, Kostas D.; Stergioulas, Nikolaos

    2009-05-01

    We investigate torsional Alfven oscillations of relativistic stars with a global dipole magnetic field, via 2D numerical simulations. We find that a) there exist two families of quasi-periodic oscillations (QPOs) with harmonics at integer multiples of the fundamental frequency, b) the QPOs are long-lived, c) for the chosen form of dipolar magnetic field, the frequency ratio of the lower to upper fundamental QPOs is about 0.6, independent of the equilibrium model or of the strength of the magnetic field, and d) within a representative sample of EOS and of various magnetar masses, the Alfven QPO frequencies are given by accurate empirical relations that depend only on the compactness of the star and on the magnetic field strength. Compared to the observational frequencies, we also obtain an upper limit on the strength of magnetic field of SGR 1806-20 (if is dominated by a dipolar component) between {approx}3 and 7x10{sup 15} Gauss.

  10. Torsional oscillations of strange stars

    NASA Astrophysics Data System (ADS)

    Mannarelli, Massimo

    2014-11-01

    Strange stars are one of the hypothetical compact stellar objects that can be formed after a supernova explosion. The existence of these objects relies on the absolute stability of strange collapsed quark matter with respect to standard nuclear matter. We discuss simple models of strange stars with a bare quark matter surface, thus standard nuclear matter is completely absent. In these models an electric dipole layer a few hundreds Fermi thick should exist close to the star surface. Studying the torsional oscillations of the electrically charged layer we estimate the emitted power, finding that it is of the order of 1045 erg/s, meaning that these objects would be among the brightest compact sources in the heavens. The associated relaxation times are very uncertain, with values ranging between microseconds and minutes, depending on the crust thickness. Although part of the radiated power should be absorbed by the electrosphere surrounding the strange star, a sizable fraction of photons should escape and be detectable.

  11. Torsion phenomenology at the CERN LHC

    SciTech Connect

    Belyaev, A. S.; Shapiro, I. L.; Vale, M. A. B. do

    2007-02-01

    We explore the potential of the CERN Large Hadron Collider (LHC) to test the dynamical torsion parameters. The form of the torsion action can be established from the requirements of consistency of effective quantum field theory. The most phenomenologically relevant part of the torsion tensor is dual to a massive axial vector field. This axial vector has geometric nature, that means it does not belong to any representation of the gauge group of the SM extension or GUT theory. At the same time, torsion should interact with all fermions, that opens the way for the phenomenological applications. We demonstrate that LHC collider can establish unique constraints on the interactions between fermions and torsion field considerably exceeding present experimental lower bounds on the torsion couplings and its mass. It is also shown how possible nonuniversal nature of torsion couplings due to the renormalization group running between the Planck and TeV energy scales can be tested via the combined analysis of Drell-Yan and tt production processes.

  12. Euler angles as torsional flat spaces

    NASA Astrophysics Data System (ADS)

    Trejo-Mandujano, Hector A.

    In this work we use general tensor calculus to compare the geodesic equation of motion and Newton's first law for force-free classical systems that are described by an arbitrary number of generalized coordinates in spaces with and without torsion. We choose as objects of study the flat torsional Euler angle metric spaces for rigid rotators. We tested the equivalence of the two motion equations using computational software that allowed algebraic manipulation. The main result is that the equivalence only holds for torsion-free spaces, and for isotropic force-free rotators. We present analytical calculations for the isotropic case and computational results for the general case.

  13. Modification of gravity due to torsion

    SciTech Connect

    Nair, V. P.; Nikiforova, V.; Randjbar-Daemi, S.; Rubakov, V.

    2010-01-01

    Modifications of general relativity have been considered as one of the possible ways of addressing some of the outstanding problems related to the large scale gravitational physics. In this contribution we review some of the recent results which are due to the inclusion of dynamical torsion. More specifically we shall discuss the propagation of massive spin-2 particles in flat and curved space times. We shall show that, contrary to what is generally believed, spinning matter is not the sole source of torsion field. A symmetric energy momentum tensor can also couple to torsion degrees of freedom. The massive and massless spin-2 particles mix giving rise to an infrared modification of gravity.

  14. Observation of coronal loop torsional oscillation

    NASA Astrophysics Data System (ADS)

    Zaqarashvili, T. V.

    2003-02-01

    We suggest that the global torsional oscillation of solar coronal loop may be observed by the periodical variation of a spectral line width. The amplitude of the variation must be maximal at the velocity antinodes and minimal at the nodes of the torsional oscillation. Then the spectroscopic observation as a time series at different heights above the active region at the solar limb may allow to determine the period and wavelength of global torsional oscillation and consequently the Alfvén speed in corona. From the analysis of early observation (Egan & Schneeberger \\cite{egan}) we suggest the value of coronal Alfvén speed as ~ 500 km s-1.

  15. Testicular torsion in the older patient

    SciTech Connect

    Perry, S.; Hoopingarner, D.; Askins, D.

    1983-05-01

    A 40-year-old man presented with severe right-sided scrotal pain and was proven to have a 720-degree right testicular torsion. Fewer than 50 documented cases of testicular torsion have been reported in men over the age of thirty. The anatomical predisposition for torsion generally selects these individuals early in life. Rapid diagnosis allowed for surgical correction and testicular salvage. We outline an expedient diagnostic approach for these difficult cases with use of the Doppler ultrasound and the technetium (99mTc) testicular scan.

  16. Considerations regarding the stress relieving in a special product

    NASA Astrophysics Data System (ADS)

    Axinte, T.; Vladu, G.

    2015-11-01

    The special product has a steel bearing structure located inside the shoulders and it is fitted with a steel cylinder loaded by an internal pressure pi. The value of the maximum internal pressure is high, at limit being equal to the allowable stress (σa = pi), where pi = 3000 MPa. The uniform stresses decrease if there is an external pressure applied on the cylinder. Therefore, it must be produced external pressure in order to reduce the stress ctmax., in other words to achieve a relieving operation. The external diameter of the internal tube is larger than the internal diameter of the external tube. In the normal temperature conditions these two cylinders cannot be assembled. After it is heated up, expanded cylinder is mounted on the internal cylinder and after the quenching, on the contact surface it appears a relieving pressure p. We are interested in computing the parameters of this technological procedure, for the classic way of relieving, namely by heating up the external cylinder. After processing by cutting, radius R2 of the internal tube is greater than δ = 0.05 mm radius R2 of the external tube. After cooling, the two tubes have a common radius R2, which will have an average value between the values they had before the assembling process. This is why the external tube has to suffer a thermal expansion, the internal tube suffering a compression, so that the two displacements summed, measured perpendicular to the contact surface, have a value of δ = 0.05 mm. After the relieving operation, on the contact surface between the two tubes will be produces a contact pressure, p. In the paper we study the effect of the relieving pressure p, onto the stresses if there would be not relieving and the variation of stresses considering relieving of both the internal tube and the external tube. The highest values of the stresses are those on the internal face of the bearing. If calculations are in accordance with the third failure theory it results that the maximum

  17. Torsion-induced effects in magnetic nanowires

    NASA Astrophysics Data System (ADS)

    Sheka, Denis D.; Kravchuk, Volodymyr P.; Yershov, Kostiantyn V.; Gaididei, Yuri

    2015-08-01

    A magnetic helix wire is one of the simplest magnetic systems which manifests properties of both curvature and torsion. Possible equilibrium magnetization states in the helix wire with different anisotropy directions are studied theoretically. There exist two equilibrium states in the helix wire with easy-tangential anisotropy: a quasitangential magnetization distribution in the case of relatively small curvatures and torsions, and an onion state in the opposite case. The curvature and torsion also essentially influence the spin-wave dynamics in the helix wire, acting as an effective magnetic field. Originated from a geometry-induced effective Dzyaloshinskii interaction, this magnetic field leads to a coupling between the helix chirality and the magnetochirality and breaks mirror symmetry in the spin-wave spectrum: the modification of magnon dispersion relation is linear with respect to the torsion and quadratic with respect to the curvature. All analytical predictions on magnetization statics and dynamics are well confirmed by direct spin-lattice simulations.

  18. DNA.

    ERIC Educational Resources Information Center

    Felsenfeld, Gary

    1985-01-01

    Structural form, bonding scheme, and chromatin structure of and gene-modification experiments with deoxyribonucleic acid (DNA) are described. Indicates that DNA's double helix is variable and also flexible as it interacts with regulatory and other molecules to transfer hereditary messages. (DH)

  19. Torsion and buckling of open sections

    NASA Technical Reports Server (NTRS)

    Wagner, Herbert

    1936-01-01

    In this paper is a discussion of the general principles for open sections of any shape. In what follows the torsion will be computed and on the basis of the results it will be possible to obtain a proper design of section in each case. The torsion of buckling members for the case where they are centrally loaded, leads to a problem in pure stability and is similar to that of stressed beams.

  20. Flow in a torsionally oscillating filled cylinder

    NASA Technical Reports Server (NTRS)

    Schafer, C. F.

    1983-01-01

    The flow of a liquid in a completely filled cylinder undergoing torsional oscillations about its longitudinal symmetry axis was studied analytically and experimentally. The objective of the studies was to determine the efficacy of the torsional oscillations in mixing the confined liquid. Flow was found to be confined primarily to toroidal cells at the ends of the cylinder. Cell thickness was about equal to the cylinder radius. The use of baffles at the end walls was shown to enhance the mixing process.

  1. Torsional Stability of Aluminum Alloy Seamless Tubing

    NASA Technical Reports Server (NTRS)

    Moore, R L; Paul, D A

    1939-01-01

    Torsion tests were made on 51ST aluminum-alloy seamless tubes having diameter-to-thickness ratios of from 77 to 139 and length-to-diameter ratios of from 1 to 60. The torsional strengths developed in the tubes which failed elastically (all tubes having lengths greater than 2 to 6 times the diameter) were in most cases within 10 percent of the value indicated by the theories of Donnel, Timoshenko, and Sturm, assuming a condition of simply supported ends.

  2. The Torsional Fundamental Band of Methylformate

    NASA Astrophysics Data System (ADS)

    Tudorie, M.; Ilyushin, V.; Vander Auwera, J.; Pirali, O.; Roy, P.; Huet, T. R.

    2011-06-01

    Methylformate (HCOOCH_3) is one of the most important molecules in astrophysics, first observed in 1975. The rotational structure of its ground and first excited torsional states are well known from millimeter wave measurements. However, some of the torsional parameters are still not precisely determined because information on the torsional vibrational frequency v_t = 1-0 is missing. To overcome that problem, the far infrared spectrum of HCOOCH_3 was recorded with a 150 m optical path in a White cell and a Bruker IFS 125 HR Fourier transform spectrometer at the AILES beamline of the synchrotron SOLEIL facility. The analysis of the very weak fundamental torsional band v_t = 1-0 observed around 130 Cm-1 was carried out. It led to the first precise determination of the torsional barrier height and the dipole moment induced by the torsional motion. This work is partly supported by the "Programme National de Physico-Chimie du Milieu Interstellaire" (PCMI-CNRS) and by the contract ANR-BLAN-08-0054. R.D. Brown, J.G. Crofts, P.D. Godfrey, F.F. Gardner, B.J. Robinson, J.B. Whiteoak, Astrophys. J. 197 (1975) L29-L31. See V. Ilyushin, A. Kryvda, E. Alekseev, J. Mol. Spectrosc. 255 (2009) 32-38, and references therein.

  3. Attentional Modulation of Eye Torsion Responses

    NASA Technical Reports Server (NTRS)

    Stevenson, Scott B.; Mahadevan, Madhumitha S.; Mulligan, Jeffrey B.

    2016-01-01

    Eye movements generally have both reflexive and voluntary aspects, but torsional eye movements are usually thought of as a reflexive response to image rotation around the line of sight (torsional OKN) or to head roll (torsional VOR). In this study we asked whether torsional responses could be modulated by attention in a case where two stimuli rotated independently, and whether attention would influence the latency of responses. The display consisted of rear-projected radial "pinwheel" gratings, with an inner annulus segment extending from the center to 22 degrees eccentricity, and an outer annulus segment extending from 22 degrees out to 45 degrees eccentricity. The two segments rotated around the center in independent random walks, stepping randomly 4 degrees clockwise or counterclockwise at 60 Hz. Subjects were asked to attend to one or the other while keeping fixation steady at the center of the display. To encourage attention on one or the other segment of the display, subjects were asked to move a joystick in synchrony with the back and forth rotations of one part of the image while ignoring the other. Eye torsion was recorded with the scleral search coil technique, sampled at 500 Hz. All four subjects showed roughly 50% stronger torsion responses to the attended compared to unattended segments. Latency varied from 100 to 150 msec across subjects and was unchanged by attention. These findings suggest that attention can influence eye movement responses that are not typically under voluntary control.

  4. INTERIOR DETAIL, SECONDSTORY JOISTS, SUBFLOORING, AND FIREPLACE HEARTH RELIEVING ARCH. ...

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

    INTERIOR DETAIL, SECOND-STORY JOISTS, SUBFLOORING, AND FIREPLACE HEARTH RELIEVING ARCH. THESE FEATURES WERE MADE VISIBLE AFTER A 2002 FAILURE OF WHAT WAS LIKELY THE ORIGINAL EIGHTEENTH-CENTURY CEILING PLASTER IN THE SOUTHWEST CABINET - The Woodlands, 4000 Woodlands Avenue, Philadelphia, Philadelphia County, PA

  5. Cross-shaped torsional spring

    DOEpatents

    Williamson, M.M.; Pratt, G.A.

    1999-06-08

    The invention provides an elastic actuator consisting of a motor and a motor drive transmission connected at an output of the motor. An elastic element is connected in series with the motor drive transmission, and this elastic element is positioned to alone support the full weight of any load connected at an output of the actuator. A single force transducer is positioned at a point between a mount for the motor and an output of the actuator. This force transducer generates a force signal, based on deflection of the elastic element, that indicates force applied by the elastic element to an output of the actuator. An active feedback force control loop is connected between the force transducer and the motor for controlling the motor. This motor control is based on the force signal to deflect the elastic element an amount that produces a desired actuator output force. The produced output force is substantially independent of load motion. The invention also provides a torsional spring consisting of a flexible structure having at least three flat sections each connected integrally with and extending radially from a central section. Each flat section extends axially along the central section from a distal end of the central section to a proximal end of the central section. 30 figs.

  6. Cross-shaped torsional spring

    DOEpatents

    Williamson, Matthew M.; Pratt, Gill A.

    1999-06-08

    The invention provides an elastic actuator consisting of a motor and a motor drive transmission connected at an output of the motor. An elastic element is connected in series with the motor drive transmission, and this elastic element is positioned to alone support the full weight of any load connected at an output of the actuator. A single force transducer is positioned at a point between a mount for the motor and an output of the actuator. This force transducer generates a force signal, based on deflection of the elastic element, that indicates force applied by the elastic element to an output of the actuator. An active feedback force control loop is connected between the force transducer and the motor for controlling the motor. This motor control is based on the force signal to deflect the elastic element an amount that produces a desired actuator output force. The produced output force is substantially independent of load motion. The invention also provides a torsional spring consisting of a flexible structure having at least three flat sections each connected integrally with and extending radially from a central section. Each flat section extends axially along the central section from a distal end of the central section to a proximal end of the central section.

  7. Strong field coherent control of molecular torsions--Analytical models.

    PubMed

    Ashwell, Benjamin A; Ramakrishna, S; Seideman, Tamar

    2015-08-14

    We introduce analytical models of torsional alignment by moderately intense laser pulses that are applicable to the limiting cases of the torsional barrier heights. Using these models, we explore in detail the role that the laser intensity and pulse duration play in coherent torsional dynamics, addressing both experimental and theoretical concerns. Our results suggest strategies for minimizing the risk of off-resonant ionization, noting the qualitative differences between the case of torsional alignment subject to a field-free torsional barrier and that of torsional alignment of a barrier-less system (equivalent to a 2D rigid rotor). We also investigate several interesting torsional phenomena, including the onset of impulsive alignment of torsions, field-driven oscillations in quantum number space, and the disappearance of an alignment upper bound observed for a rigid rotor in the impulsive torsional alignment limit. PMID:26277138

  8. Torsional oscillations in dynamo simulations

    NASA Astrophysics Data System (ADS)

    Wicht, Johannes; Christensen, Ulrich R.

    2010-06-01

    Cylinders aligned with the planetary rotation axis have a special significance in the dynamics of planetary dynamo regions. The azimuthal Lorentz forces on these geostrophic cylinders is expected to cancel to a large degree, establishing the so-called Taylor state. Deviations from this state take the form of torsional oscillations (TOs) that are supposed to represent important fast flow variations. These oscillations have reportedly been identified in the secular variation signal from the top of Earth's core. We have performed several dynamo simulations at different parameters to check whether Taylor state and TOs can also be identified in a numerical model. Taylor states are approached when viscous effects are small at Ekman numbers of E = 3 × 10-5 or below and Reynolds stresses are kept low by choosing moderate Rayleigh numbers. One-dimensional magnetic Alfvén waves that travel towards the boundaries then become prominent in the motion of the geostrophic cylinders. These waves obey the TO theory but are also damped and modified by other effects. For example, fast variations of likely convective origin remain important in all our simulations. Reynolds stresses may play a more sizable role for the dynamics in Earth's dynamo region than commonly assumed. They may also contribute to the motions of geostrophic cylinders and severely reduce the significance of TOs for the fast core dynamics. The amplitude of TOs amounts to not more than a few percent of the total flow amplitude in the simulations, which renders these motions insignificant for the long-term dynamo process.

  9. Endodontic instruments after torsional failure: nanoindentation test.

    PubMed

    Jamleh, Ahmed; Sadr, Alireza; Nomura, Naoyuki; Ebihara, Arata; Yahata, Yoshio; Hanawa, Takao; Tagami, Junji; Suda, Hideaki

    2014-01-01

    This study aimed to evaluate effects of torsional loading on the mechanical properties of endodontic instruments using the nanoindentation technique. ProFile (PF; size 30, taper 04; Dentsply Maillefer, Switzerland) and stainless steel (SS; size 30, taper 02; Mani, Japan) instruments were subjected to torsional test. Nanoindentation was then performed adjacent to the edge of fracture (edge) and at the cutting part beside the shank (shank). Hardness and elastic modulus were measured under 100-mN force on 100 locations at each region, and compared to those obtained from the same regions on new instruments. It showed that PF and SS instruments failed at 559 ± 67 and 596 ± 73 rotation degrees and mean maximum torque of 0.90 ± 0.07 and 0.99 ± 0.05 N-cm, respectively. Hardness and elastic modulus ranged 4.8-6.7 and 118-339 GPa in SS, and 2.7-3.2 and 52-81 GPa in PF. Significant differences between torsion-fractured and new instruments in hardness and elastic modulus were detected in the SS system used. While in PF system, the edge region after torsional fracture had significantly lower hardness and elastic modulus compared to new instruments. The local hardness and modulus of elasticity of endodontic instruments adjacent to the fracture edge are significantly reduced by torsional loading. PMID:24610598

  10. Mechanical behavior of twinned SiC nanowires under combined tension-torsion and compression-torsion strain

    SciTech Connect

    Li, Zhijie; Wang, Shengjie; Wang, Zhiguo; Zu, Xiaotao T.; Gao, Fei; Weber, William J.

    2010-07-01

    The mechanical behavior of twinned silicon carbide (SiC) nanowires under combined tension-torsion and compression-torsion is investigated using molecular dynamics simulations with an empirical potential. The simulation results show that both the tensile failure stress and buckling stress decrease under combined tension-torsional and combined compression-torsional strain, and they decrease with increasing torsional rate under combined loading. The torsion rate has no effect on the elastic properties of the twinned SiC nanowires. The collapse of the twinned nanowires takes place in a twin stacking fault of the nanowires.

  11. Ritual relieved axial dystonia triggered by gaze-evoked amaurosis.

    PubMed

    Jacome, D E

    1997-11-01

    A woman with chronic posttraumatic axial lateropulsion cervical dystonia ("belly dancer's head") found relief of her spontaneous dystonic spasms by the sequential performance of an elaborate motor ritual. During an episode of left optic papillitis caused by central retinal vein occlusion, gaze-evoked amaurosis of the left eye developed, preceded by achromatopsia, during left lateral gaze. Gaze-evoked amaurosis triggered axial dystonia, which was followed by her unique, stereotyped, dystonia-relieving ritual that simulated a slow dance. Visual symptoms improved progressively in 1 year. Eventually, she was unable to trigger her dystonia by eye movements. Spontaneous dystonia remained otherwise unchanged from before the episode of papillitis and was still relieved by her unique ritual. PMID:9365340

  12. Do OTC remedies relieve cough in acute URIs?

    PubMed

    Dealleaume, Lauren; Tweed, Beth; Neher, Jon O

    2009-10-01

    Dextromethorphan (DM) for adults and honey for children provide some relief. DM may modestly decrease cough in adults compared with placebo. The data supporting zinc for the common cold are mixed. Antihistamines, antihistamine-decongestant combinations, and guaifenesin do not provide greater relief than placebo in adults. In children, antihistamines, decongestants, DM, or combinations of them do not relieve cough better than placebo. Honey may modestly decrease frequency and severity of cough compared with DM or no treatment. PMID:19874728

  13. DNA

    ERIC Educational Resources Information Center

    Stent, Gunther S.

    1970-01-01

    This history for molecular genetics and its explanation of DNA begins with an analysis of the Golden Jubilee essay papers, 1955. The paper ends stating that the higher nervous system is the one major frontier of biological inquiry which still offers some romance of research. (Author/VW)

  14. Aeroelastic considerations for torsionally soft rotors

    NASA Technical Reports Server (NTRS)

    Mantay, W. R.; Yeager, W. T., Jr.

    1985-01-01

    A research study was initiated to systematically determine the impact of selected blade tip geometric parameters on conformable rotor performance and loads characteristics. The model articulated rotors included baseline and torsionally soft blades with interchangeable tips. Seven blade tip designs were evaluated on the baseline rotor and six tip designs were tested on the torsionally soft blades. The designs incorporated a systemmatic variation in geometric parameters including sweep, taper, and anhedral. The rotors were evaluated in the NASA Langley Transonic Dynamics Tunnel at several advance ratios, lift and propulsive force values, and tip Mach numbers. A track sensitivity study was also conducted at several advance ratios for both rotors. Based on the test results, tip parameter variations generated significant rotor performance and loads differences for both baseline and torsionally soft blades.

  15. Surgical correction of torsion of the penis.

    PubMed

    Azmy, A; Eckstein, H B

    1981-08-01

    Torsion of the penis is a rare anomaly, believed to be due to abnormal skin attachment and not to any structural abnormality of the corpora. The rotation is usually to the left in a counter-clockwise fashion. The urethral meatus is placed in a oblique position and the median raphe makes a spiral curve from the base of the penis towards the meatus. Three boys with congenital torsion of the penis are reported. A corrective operative for this condition is described. Penile torsion was first described by Verneuil in 1857, but in the past no operative correction was recommended, since attempts to move the skin around were believed not to correct the spiral alignment of the corpora cavernosa. PMID:7260553

  16. Active structures to reduce torsional vibrations

    NASA Astrophysics Data System (ADS)

    Matthias, M.; Schlote, D.; Atzrodt, H.

    2013-03-01

    This paper describes the development of different active measures to reduce torsional vibrations in power trains. The measures are based on concepts developed for active mounts to reduce the transmission of structure-borne sound. To show the potential of these active measures and investigate their mode of operation to influence torsional vibrations, numerical simulations of powertrains with different active measures were done. First experimental results from tests on an experimental (reduced size) power train were used to align the numerical models. The work was done within the project 'LOEWE-Zentrum AdRIA: Adaptronik - Research, Innovation, Application' funded by the German federal state of Hessen, and the Project AKTos: 'Active control of torsional vibrations by coupling elements' placed in the research Framework program 'Navigation and Maritime Technology for the 21st Century' funded by the German Federal Ministry of Economics and Technology.

  17. Helioseismic measurement of solar torsional oscillations.

    PubMed

    Vorontsov, S V; Christensen-Dalsgaard, J; Schou, J; Strakhov, V N; Thompson, M J

    2002-04-01

    Bands of slower and faster rotation, the so-called torsional oscillations, are observed at the Sun's surface to migrate in latitude over the 11-year solar cycle. Here, we report on the temporal variations of the Sun's internal rotation from solar p-mode frequencies obtained over nearly 6 years by the Michelson Doppler Imager (MDI) instrument on board the Solar and Heliospheric Observatory (SOHO) satellite. The entire solar convective envelope appears to be involved in the torsional oscillations, with phase propagating poleward and equatorward from midlatitudes at all depths throughout the convective envelope. PMID:11935019

  18. Tussive syncope in a pug with lung-lobe torsion

    PubMed Central

    Davies, John A.; Snead, Elisabeth C.R.; Pharr, John W.

    2011-01-01

    The most common presenting clinical signs of lung-lobe torsion include dyspnea, tachypnea, lethargy, and anorexia. Tussive syncope secondary to lung-lobe torsion has not been documented. This article describes the presentation, diagnosis, management, and outcome of a pug with tussive syncope secondary to lung-lobe torsion. PMID:22131584

  19. Best Way to Take Your Over-the-Counter Pain Reliever? Seriously.

    MedlinePlus

    ... best way to take your over-the-counter pain reliever? Seriously. Share Tweet Linkedin Pin it More sharing ... Print (PDF version - 6MB) Over-the-counter (OTC) pain relievers/fever reducers (the kind you can buy without ...

  20. Cryptorchid testis with torsion: Inguinoscrotal whirlpool sign

    PubMed Central

    Indiran, Venkatraman

    2016-01-01

    Non contrast helical computed tomography (CT) study of the abdomen is frequently performed in evaluation of suspected ureteric colic. We present CT images of a young adult male patient who had torsion of an undescended, non-neoplastic testis and describe the “Inguinoscrotal whirlpool sign on CT”. PMID:27555688

  1. Adnexal torsion: review of the literature.

    PubMed

    Sasaki, Kirsten J; Miller, Charles E

    2014-01-01

    Adnexal torsion is one of a few gynecologic surgical emergencies. Misdiagnosis or delay in treatment can have permanent sequelae including loss of an ovary with effect on future fertility, peritonitis, and even death. A PubMed search was performed between 1985 and 2012 for reviews, comparative studies, and case reports to provide a review of the epidemiology, risk factors, clinical presentation, common laboratory and imaging findings, and treatments of adnexal torsion. Common symptoms of torsion include pain, nausea, and vomiting, with associated abdominal or pelvic tenderness, and may differ in premenarchal and pregnant patients. Laboratory and imaging findings including ultrasound with Doppler analysis, computed tomography, and magnetic resonance imaging can assist in making the diagnosis but should not trump clinical judgment; normal Doppler flow can be observed in up to 60% of adnexal torsion cases. Treatment depends on the individual patient but commonly includes detorsion, even if the adnexae initially seem necrotic, with removal of any associated cysts or salpingo-oophorectomy, because recurrence rates are higher with detorsion alone or detorsion with only cyst aspiration. PMID:24126258

  2. Joining and forming using torsional ultrasonic principles.

    PubMed

    Frost, M

    2009-10-01

    Developments in torsional ultrasonic joining mean that it is now used in a diverse range of joining, forming, selective weakening and "break-off" applications in the medical device industry.The principles and benefits of the technique are described together with application examples. PMID:20302140

  3. Torsional Oscillations of the Earths's Core

    NASA Technical Reports Server (NTRS)

    Hide, Raymond; Boggs, Dale H.; Dickey, Jean O.

    1997-01-01

    Torsional oscillations of the Earth's liquid metallic outer core are investigated by diving the core into twenty imaginary e1qui-volume annuli coaxial with the axis of ratation of the Earth and determining temproal fluctuations in the axial component of angular memonetum of each annulus under the assumption of iso-rotation on cylindrical surfaces.

  4. Hepatic lobe torsion in a horse

    PubMed Central

    Bentz, Kristin J.; Burgess, Brandy A.; Lohmann, Katharina L.; Shahriar, Farshid

    2009-01-01

    A 4-year-old Belgian mare was presented with a 1-week history of fever, suspected of being caused by peritonitis. The mare died before the diagnostic procedures had been completed; postmortem examination revealed torsion of the left medial lobe of the liver, resulting in diffuse necrosis of liver tissue and severe peritoneal effusion. PMID:19436480

  5. 31 CFR 585.521 - Donations of food to relieve human suffering authorized.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Donations of food to relieve human... Donations of food to relieve human suffering authorized. (a) Specific licenses may be issued on a case-by-case basis to permit exportation to the FRY (S&M) of donated food intended to relieve human...

  6. Robot Drills Holes To Relieve Excess Tire Pressures

    NASA Technical Reports Server (NTRS)

    Carrott, David T.

    1996-01-01

    Small, relatively inexpensive, remotely controlled robot called "tire assault vehicle" (TAV) developed to relieve excess tire pressures to protect ground crew, aircraft equipment, and nearby vehicles engaged in landing tests of CV-990 Landing System Research Aircraft. Reduces costs and saves time in training, maintenance, and setup related to "yellow" and "red" tire conditions. Adapted to any heavy-aircraft environment in which ground-crew safety at risk because of potential for tire explosions. Also ideal as scout vehicle for performing inspections in hazardous locations.

  7. Design and analysis of a torsion braid pendulum displacement transducer

    NASA Technical Reports Server (NTRS)

    Rind, E.; Bryant, E. L.

    1981-01-01

    The dynamic properties at various temperatures of braids impregnated with polymer can be measured by using the braid as the suspension of a torsion pendulum. This report describes the electronic and mechanical design of a torsional braid pendulum displacement transducer which is an advance in the state of the art. The transducer uses a unique optical design consisting of refracting quartz windows used in conjunction with a differential photocell to produce a null signal. The release mechanism for initiating free torsional oscillation of the pendulum has also been improved. Analysis of the precision and accuracy of the transducer indicated that the maximum relative error in measuring torsional amplitude was approximately 0. A serious problem inherent in all instruments which use a torsional suspension was analyzed: misalignment of the physical and torsional axes of the torsional member which results in modulation of the amplitude of the free oscillation.

  8. Evaluation of left ventricular torsion by cardiovascular magnetic resonance

    PubMed Central

    2012-01-01

    Recently there has been considerable interest in LV torsion and its relationship with symptomatic and pre-symptomatic disease processes. Torsion gives useful additional information about myocardial tissue performance in both systolic and diastolic function. CMR assessment of LV torsion is simply and efficiently performed. However, there is currently a wide variation in the reporting of torsional motion and the procedures used for its calculation. For example, torsion has been presented as twist (degrees), twist per length (degrees/mm), shear angle (degrees), and shear strain (dimensionless). This paper reviews current clinical applications and shows how torsion can give insights into LV mechanics and the influence of LV geometry and myocyte fiber architecture on cardiac function. Finally, it provides recommendations for CMR measurement protocols, attempts to stimulate standardization of torsion calculation, and suggests areas of useful future research. PMID:22827856

  9. Are children given insufficient pain-relieving medication postoperatively?

    PubMed

    Hamers, J P; Abu-Saad, H H; van den Hout, M A; Halfens, R J

    1998-01-01

    The literature often suggests and assumes that children are under-medicated postoperatively. A review of the literature leads to the conclusion that only a few studies answer the question of whether children's pain is relieved insufficiently. The lack of consensus on expected pain intensity after surgery and caution about prescribing analgesics could explain why analgesics are often prescribed on a pro re nata (prn) basis. Prescription on a prn basis, in fact, means that the nurse makes the decision whether or not an analgesic should be administered. Some studies suggest, however, that nurses under-medicate children and that postoperative pain is relieved insufficiently. In some situations, nurses under-estimate the child's pain, while in others, nurses' attitudes, beliefs and knowledge regarding pain relief strategies play an important role. On the basis of this review of the literature standard prescription of pain medication instead of prn is recommended. Furthermore, research on the incidence and prevalence of pain in children and on the effectiveness of analgesic administration postoperatively is warranted. PMID:9515606

  10. Sodium Hydrosulfide Relieves Neuropathic Pain in Chronic Constriction Injured Rats

    PubMed Central

    Lin, Jian-qing; Luo, Hui-qin; Lin, Cai-zhu; Chen, Jin-zhuan; Lin, Xian-zhong

    2014-01-01

    Aberrant neuronal activity in injured peripheral nerves is believed to be an important factor in the development of neuropathic pain (NPP). Channel protein pCREB of that activity has been shown to mitigate the onset of associated molecular events in the nervous system, and sodium hydrosulfide (NaHS) could inhibit the expression of pCREB. However, whether NaHS could relieve the pain, it needs further experimental research. Furthermore, the clinical potential that NaHS was used to relieve pain was limited so it would be required. To address these issues, the rats of sciatic nerve chronic constriction injury (CCI) were given intraperitoneal injection of NaHS containing hydrogen sulfide (H2S). The experimental results showed that NaHS inhibited the reduction of paw withdrawal thermal latency (PWTL), mechanical withdrawal threshold (MWT), and the level of pCREB in CCI rats in a dose-dependent manner and they were greatly decreased in NaHSM group (P < 0.05). NaHS alleviates chronic neuropathic pain by inhibiting expression of pCREB in the spinal cord of Sprague-Dawley rats. PMID:25506383

  11. Laser-Based Measurement Of Torsional Vibration

    NASA Astrophysics Data System (ADS)

    Eastwood, P. G.; Halliwell, N. A.

    1986-07-01

    Investigations of the torsional vibration characteristics of shaft systems which transmit pulsating torques are an important part of a machinery designer's responsibility. Satisfactory operation of such systems depends to a large extent on successful treatment of this vibration problem, since incorrectly or insufficiently controlled torsional oscillations can lead to fatigue failure, rapid bearing wear, gear hammer etc. The problem is particularly severe in engine crankshaft design where numerous failures have been traced to abnormal vibration at "critical" speeds. Traditionally, the monitoring of torsional oscillation has been performed using strain gauges, slip rings and a variety of mechanical and electrical "torsiographs". More recently systems employing slotted discs or toothed wheels together with proximity transducers have been preferred, but a disadvantage arises from all these methods in that they require contact with the rotating component which necessitates "downtime" for transducer attachment. Moreover, physical access to the rotating surface is often restricted thus making the use of such methods impractical. The "cross-beam" laser velocimeter provides a means of measuring torsional vibration by a non-contact method, thus effectively overcoming the disadvantages of previous measurement systems. This well established laser-based instrument provides a time-resolved voltage analogue of shaft tangential surface velocity and laboratory and field tests have shown it to be both accurate and reliable. The versatility of this instrument, however, is restricted by the need for accurate positioning, since the velocimeter must be arranged so that the rotating surface always traverses the beam intersection region, which is typically only a fraction of a millimetre in length. As a consequence use is restricted to components of circular cross section. This paper compares and contrasts the "cross-beam" system with a new laser instrument, the laser torsional vibrometer

  12. Axial and torsional fatigue behavior of Waspaloy

    NASA Technical Reports Server (NTRS)

    Zamrik, S.; Mirdamadi, M.; Zahiri, F.

    1986-01-01

    The cyclic flow response and crack growth behavior of Waspaloy at room temperature and 650 C under tensile loading and torsional loading was studied, for two conditions of Waspaloy: fine grain, large gamma prime size; coarse grain, small gamma prime size. The fine grain material showed 5 to 10 percent hardening after about 10 percent of life, with sequent softening to failure at both themperature levels. The coarse grain material showed either stable response or monotonic softening to failure. Early crack initiation was observed on planes of maximum shear, with eventual branching to principle planes under torsional loading; cracks were always normal to load axis under tensile loading. Also, crack paths were intergranular at 650 C, mostly transgranular at room temperature.

  13. Torsion and transverse bending of cantilever plates

    NASA Technical Reports Server (NTRS)

    Reissner, Eric; Stein, Manuel

    1951-01-01

    The problem of combined bending and torsion of cantilever plates of variable thickness, such as might be considered for solid thin high-speed airplane or missile wings, is considered in this paper. The deflections of the plate are assumed to vary linearly across the chord; minimization of the potential energy by means of the calculus of variations then leads to two ordinary linear differential equations for the bending deflections and the twist of the plate. Because the cantilever is analyzed as a plate rather than as a beam, the effect of constraint against axial warping in torsion is inherently included. The application of this method to specific problems involving static deflection, vibration, and buckling of cantilever plates is presented. In the static-deflection problems, taper and sweep are considered.

  14. Torsional Tribological Behavior and Torsional Friction Model of Polytetrafluoroethylene against 1045 Steel

    PubMed Central

    Wang, Shibo; Niu, Chengchao

    2016-01-01

    In this work, the plane-on-plane torsional fretting tribological behavior of polytetrafluoroethylene (PTFE) was studied. A model of a rigid, flat-ended punch acting on an elastic half-space was built according to the experimental conditions. The results indicate that the shape of T–θ curves was influenced by both the torsional angle and the normal load. The torsion friction torque and wear rate of PTFE exponentially decreased when the torsion angle rose. The torsional torque increased from 0.025 N·m under a normal load of 43 N to 0.082 N·m under a normal load of 123 N. With sequentially increasing normal load, the value of torque was maintained. With rising normal load, the wear mass loss of PTFE disks was increased and the wear rate was decreased. Good agreement was found with the calculated torque according to the model and the experimental torque except for that under a normal load of 163 N. The difference under a normal load of 163 N was caused by the coefficient of friction. Usually the coefficient of friction of a polymer decreases with increasing normal load, whereas a constant coefficient of friction was applied in the model. PMID:26799324

  15. Torsional Tribological Behavior and Torsional Friction Model of Polytetrafluoroethylene against 1045 Steel.

    PubMed

    Wang, Shibo; Niu, Chengchao

    2016-01-01

    In this work, the plane-on-plane torsional fretting tribological behavior of polytetrafluoroethylene (PTFE) was studied. A model of a rigid, flat-ended punch acting on an elastic half-space was built according to the experimental conditions. The results indicate that the shape of T-θ curves was influenced by both the torsional angle and the normal load. The torsion friction torque and wear rate of PTFE exponentially decreased when the torsion angle rose. The torsional torque increased from 0.025 N·m under a normal load of 43 N to 0.082 N·m under a normal load of 123 N. With sequentially increasing normal load, the value of torque was maintained. With rising normal load, the wear mass loss of PTFE disks was increased and the wear rate was decreased. Good agreement was found with the calculated torque according to the model and the experimental torque except for that under a normal load of 163 N. The difference under a normal load of 163 N was caused by the coefficient of friction. Usually the coefficient of friction of a polymer decreases with increasing normal load, whereas a constant coefficient of friction was applied in the model. PMID:26799324

  16. Analytic Model for the Rototranslational Torsion Pendulum

    NASA Astrophysics Data System (ADS)

    De Marchi, F.; Bassan, M.; Pucacco, G.; Marconi, L.; Stanga, R.; Visco, M.

    2013-01-01

    We develop an analytic model to describe the motion of the RotoTranslational Torsion Pendulum PETER in a wide range of frequencies (from 1mHz up to 10-15Hz). We also try to explain some unexpected features we found in the data with only 1 soft degree of freedom and we estimate values for the misalignment angles and other parameters of the model.

  17. Dark spinors with torsion in cosmology

    SciTech Connect

    Boehmer, Christian G.; Burnett, James

    2008-11-15

    We solve one of the open problems in Einstein-Cartan theory, namely, we find a natural matter source whose spin angular momentum tensor is compatible with the cosmological principle. We analyze the resulting evolution equations and find that an epoch of accelerated expansion is an attractor. The torsion field quickly decays in that period. Our results are interpreted in the context of the standard model of cosmology.

  18. Implementing torsional-mode Doppler ladar.

    PubMed

    Fluckiger, David U

    2002-08-20

    Laguerre-Gaussian laser modes carry orbital angular momentum as a consequence of their helical-phase front screw dislocation. This torsional beam structure interacts with rotating targets, changing the orbital angular momentum (azimuthal Doppler) of the scattered beam because angular momentum is a conserved quantity. I show how to measure this change independently from the usual longitudinal momentum (normal Doppler shift) and derive the apropos coherent mixing efficiencies for monostatic, truncated Laguerre and Gaussian-mode ladar antenna patterns. PMID:12206220

  19. Fluid driven torsional dipole seismic source

    DOEpatents

    Hardee, Harry C.

    1991-01-01

    A compressible fluid powered oscillating downhole seismic source device capable of periodically generating uncontaminated horizontally-propagated, shear waves is provided. A compressible fluid generated oscillation is created within the device which imparts an oscillation to a housing when the device is installed in a housing such as the cylinder off an existing downhole tool, thereby a torsional seismic source is established. Horizontal waves are transferred to the surrounding bore hole medium through downhole clamping.

  20. Ubiquitous Torsional Motions in Type II Spicules

    NASA Astrophysics Data System (ADS)

    De Pontieu, B.; Carlsson, M.; Rouppe van der Voort, L. H. M.; Rutten, R. J.; Hansteen, V. H.; Watanabe, H.

    2012-06-01

    Spicules are long, thin, highly dynamic features that jut out ubiquitously from the solar limb. They dominate the interface between the chromosphere and corona and may provide significant mass and energy to the corona. We use high-quality observations with the Swedish 1 m Solar Telescope to establish that so-called type II spicules are characterized by the simultaneous action of three different types of motion: (1) field-aligned flows of order 50-100 km s-1, (2) swaying motions of order 15-20 km s-1, and (3) torsional motions of order 25-30 km s-1. The first two modes have been studied in detail before, but not the torsional motions. Our analysis of many near-limb and off-limb spectra and narrowband images using multiple spectral lines yields strong evidence that most, if not all, type II spicules undergo large torsional modulation and that these motions, like spicule swaying, represent Alfvénic waves propagating outward at several hundred km s-1. The combined action of the different motions explains the similar morphology of spicule bushes in the outer red and blue wings of chromospheric lines, and needs to be taken into account when interpreting Doppler motions to derive estimates for field-aligned flows in spicules and determining the Alfvénic wave energy in the solar atmosphere. Our results also suggest that large torsional motion is an ingredient in the production of type II spicules and that spicules play an important role in the transport of helicity through the solar atmosphere.

  1. UBIQUITOUS TORSIONAL MOTIONS IN TYPE II SPICULES

    SciTech Connect

    De Pontieu, B.; Hansteen, V. H.; Carlsson, M.; Rouppe van der Voort, L. H. M.; Rutten, R. J.; Watanabe, H.

    2012-06-10

    Spicules are long, thin, highly dynamic features that jut out ubiquitously from the solar limb. They dominate the interface between the chromosphere and corona and may provide significant mass and energy to the corona. We use high-quality observations with the Swedish 1 m Solar Telescope to establish that so-called type II spicules are characterized by the simultaneous action of three different types of motion: (1) field-aligned flows of order 50-100 km s{sup -1}, (2) swaying motions of order 15-20 km s{sup -1}, and (3) torsional motions of order 25-30 km s{sup -1}. The first two modes have been studied in detail before, but not the torsional motions. Our analysis of many near-limb and off-limb spectra and narrowband images using multiple spectral lines yields strong evidence that most, if not all, type II spicules undergo large torsional modulation and that these motions, like spicule swaying, represent Alfvenic waves propagating outward at several hundred km s{sup -1}. The combined action of the different motions explains the similar morphology of spicule bushes in the outer red and blue wings of chromospheric lines, and needs to be taken into account when interpreting Doppler motions to derive estimates for field-aligned flows in spicules and determining the Alfvenic wave energy in the solar atmosphere. Our results also suggest that large torsional motion is an ingredient in the production of type II spicules and that spicules play an important role in the transport of helicity through the solar atmosphere.

  2. Liver lobe torsion in three adult rabbits.

    PubMed

    Wenger, S; Barrett, E L; Pearson, G R; Sayers, I; Blakey, C; Redrobe, S

    2009-06-01

    This paper describes three cases of liver lobe torsion in rabbits presenting with anorexia, lethargy, jaundice and abdominal pain. This condition was associated with anaemia and elevation of alanine aminotransferase, aspartate aminotransferase and gamma-glutamyl transferase. Abnormal radiological findings included hepatomegaly, gas-filled intestinal loops consistent with gastrointestinal ileus and ascites. Ultrasonographic findings included heterogeneous liver parenchyma, free abdominal fluid and reduced bowel motility. Diagnosis was confirmed by histopathological examination of the liver in all three cases. PMID:19527423

  3. Torsional optokinetic nystagmus: normal response characteristics

    PubMed Central

    Farooq, S J; Proudlock, F A; Gottlob, I

    2004-01-01

    Background/aims: Few studies have investigated normal response characteristics of torsional optokinetic nystagmus (tOKN). The authors have investigated the effect of stimulus velocity and central/peripheral stimulation on tOKN. Methods: Torsional OKN was elicited using a sinusoidal grating rotating at velocities of 3°/s to 1000°/s in clockwise and anticlockwise directions. To investigate the effect of central stimulation, stimulus size was varied from 2.86° to 50.8°. An artificial scotoma placed over a 50.8° stimulus was varied from 2.86° to 43.2° to investigate peripheral stimulation. Eight subjects participated in each experiment and torsional eye movements were recorded using video-oculography. The mean slow phase velocity (MSPV) and gain were calculated. Results: The maximum gain occurred in response to 8°/s stimulation. The MSPV increased up to a stimulus velocity of 200°/s achieving a maximum of 3°/s in both directions. MSPV was linearly correlated with the log of stimulus velocity. The smallest field size, rotating at 40°/s, evoked 10% of the gain elicited by the largest display. When the most peripheral stimulus was used, the gain was maintained at 50% of the gain evoked when the full display was used. Conclusions: A wide range of stimulus velocities can elicit tOKN and peripheral field stimulation contributes significantly to its response. PMID:15148215

  4. Fundamentals of IC engine torsional vibration

    SciTech Connect

    Doughty, S.

    1988-01-01

    Fluctuations in IC engine cylinder pressure are an obvious source of torsional vibration excitation, although the details of the coupling from cylinder pressure to torque on the crankshaft are complicated. A second, less obvious source of torsional excitation is the effect of variable inertia associated with the engine slider-crank mechanism. This is a tutorial paper, intended to show the relation between, on the one hand, the actual engine slider-crank mechanism subject to combustion gas pressure and, on the other hand, the models commonly used for torsional vibration analysis that involve constant inertias subject to torques expressed by Fourier series. As such, it uses some new approaches to reach previously known results with a greater degree of physical insight. The presentation is in terms of a single cylinder, two stroke engine with load, and makes clear the roles of piston mass, connecting rod mass and moment of inertia, and crank inertia as they affect both the effective inertia and the effective torque. The determination of natural frequencies and the forced vibration response calculation are briefly described to complete the analysis. The development of a Fourier series representation for the effective torque, including both the cylinder pressure and inertia variation is also discussed. The various components for the response are identified, in an effort to clarify the meaning of terms such as ''zero frequency mode,'' ''rigid body mode,'' and ''twisting mode.''

  5. Perinatal testicular torsion and medicolegal considerations.

    PubMed

    Massoni, F; Troili, G M; Pelosi, M; Ricci, S

    2014-06-01

    Perinatal testicular torsion (PTT) is a very complex condition because of rarity of presentation and diagnostic and therapeutic difficulties. In presence of perinatal testicular torsion, the involvement of contralateral testis can be present also in absence of other indications which suggest the bilateral involvement; therefore, occurrences supported by literature do not exclude the use of surgery to avoid the risk of omitted or delayed diagnosis. The data on possible recovery of these testicles are not satisfactory, and treatment consists of an observational approach ("wait-and-see") or an interventional approach. The hypothesis of randomized clinical trials seems impracticable because of rarity of disease. The authors present a case of PTT, analyzing injuries due to clinical and surgical management of these patients, according to medicolegal profile. The delayed diagnosis and the choice of an incorrect therapeutic approach can compromise the position of healthcare professionals, defective in terms of skill, prudence and diligence. Endocrine insufficiency is an unfortunate event. The analysis of literature seems to support, because of high risk, a surgical approach aimed not only at resolution of unilateral pathology or prevention of a relapse, but also at prevention of contralateral testicular torsion. PMID:24826979

  6. Torsional Oscillator Studies on Solid Helium

    NASA Astrophysics Data System (ADS)

    Kim, Duk Y.; Chan, Moses H. W.

    2014-03-01

    In 2004, the series of torsional oscillator (TO) experiments by Kim and Chan initiated considerable research activities on the supersolidity of helium. However, recent experiments in rigid torsional oscillators which reduce the effect of stiffening of bulk solid helium at low temepratures showed very small or negligible changes in the resonant period. A new TO experiment of solid helium confined in porous Vycor glass with no bulk solid helium in the sample cell show no evidence of supersolidity. Moreover, we have repeated an earlier experiment on hcp 3He solid, which shows similar low temperature stiffening like hcp 4He. We found that the small drop of the resonant period measured in the hcp 3He samples is comparable to that measured in the hcp 4He samples. These results confirm that the resonant period drops in torsional oscillators are consequence of the shear modulus stiffening effect in solid helium. Remaining issues and open questions on the supersolidity will be discussed. Support for this experiment was provided by NSF Grants No. DMR 1103159.

  7. Isolated fallopian tube torsion in adolescents.

    PubMed

    Rajaram, S; Bhaskaran, S; Mehta, S

    2013-01-01

    Background. Fallopian tube torsion is a rare cause of acute abdomen, occurring commonly in females of reproductive age. It lacks pathognomonic symptoms, signs, or imaging features, thus causing delay in surgical intervention. Case. We report two cases of isolated fallopian tube torsion in adolescent girls. In the first case a 19-year-old patient presented with acute pain in the left iliac region associated with episodes of vomiting for one day and mild tenderness on examination. Laparoscopy revealed left sided twisted fallopian tube associated with hemorrhagic cyst of ovary. The tube was untwisted and salvaged. In another case an 18-year-old virgin girl presented with similar complaints since one week, associated with mild tenderness in the lower abdomen and tender cystic mass on per rectal examination. On laparoscopy right twisted fallopian tube associated with a paratubal cyst was found. Salpingectomy was done as the tube was gangrenous. Conclusion. Fallopian tube torsion, though rare, should be considered in women of reproductive age with unilateral pelvic pain. Early diagnostic laparoscopy is important for an accurate diagnosis and could salvage the tube. PMID:24251052

  8. Torsional oscillations in the solar convection zone

    NASA Astrophysics Data System (ADS)

    Covas, E.; Tavakol, R.; Moss, D.; Tworkowski, A.

    2000-08-01

    Recent analysis of the helioseismic observations indicate that the previously observed surface torsional oscillations extend significantly downwards into the solar convection zone. In an attempt to understand these oscillations, we study the nonlinear coupling between the magnetic field and the solar differential rotation in the context of a mean field dynamo model, in which the nonlinearity is due to the action of the azimuthal component of the Lorentz force of the dynamo generated magnetic field on the solar angular velocity. The underlying zero order angular velocity is chosen to be consistent with the most recent helioseismic data. The model produces butterfly diagrams which are in qualitative agreement with the observations. It displays torsional oscillations that penetrate into the convection zone, and which with time migrate towards the equator. The period of these oscillations is found to be half that of the period of the global magnetic fields. This is compatible with the observed period of the surface torsional oscillations. Inside the convection zone, this is a testable prediction that is not ruled out by the observations so far available.

  9. Does nebulized fentanyl relieve dyspnea during exercise in healthy man?

    PubMed

    Kotrach, Houssam G; Bourbeau, Jean; Jensen, Dennis

    2015-06-01

    Few therapies exist for the relief of dyspnea in restrictive lung disorders. Accumulating evidence suggests that nebulized opioids selective for the mu-receptor subtype may relieve dyspnea by modulating intrapulmonary opioid receptor activity. Our respective primary and secondary objectives were to test the hypothesis that nebulized fentanyl (a mu-opioid receptor agonist) relieves dyspnea during exercise in the presence of abnormal restrictive ventilatory constraints and to identify the physiological mechanisms of this improvement. In a randomized, double-blind, placebo-controlled crossover study, we examined the effect of 250 μg nebulized fentanyl, chest wall strapping (CWS), and their interaction on detailed physiological and perceptual responses to constant work rate cycle exercise (85% of maximum incremental work rate) in 14 healthy, fit young men. By design, CWS decreased vital capacity by ∼20% and mimicked the negative consequences of a mild restrictive lung disorder on exercise endurance time and on dyspnea, breathing pattern, dynamic operating lung volumes, and diaphragmatic electromyographic and respiratory muscle function during exercise. Compared with placebo under both unrestricted control and CWS conditions, nebulized fentanyl had no effect on exercise endurance time, integrated physiological response to exercise, sensory intensity, unpleasantness ratings of exertional dyspnea. Our results do not support a role for intrapulmonary opioids in the neuromodulation of exertional dyspnea in health nor do they provide a physiological rationale for the use of nebulized fentanyl in the management of dyspnea due to mild restrictive lung disorders, specifically those arising from abnormalities of the chest wall and not affiliated with airway inflammation. PMID:26031762

  10. Does nebulized fentanyl relieve dyspnea during exercise in healthy man?

    PubMed Central

    Kotrach, Houssam G.; Bourbeau, Jean

    2015-01-01

    Few therapies exist for the relief of dyspnea in restrictive lung disorders. Accumulating evidence suggests that nebulized opioids selective for the mu-receptor subtype may relieve dyspnea by modulating intrapulmonary opioid receptor activity. Our respective primary and secondary objectives were to test the hypothesis that nebulized fentanyl (a mu-opioid receptor agonist) relieves dyspnea during exercise in the presence of abnormal restrictive ventilatory constraints and to identify the physiological mechanisms of this improvement. In a randomized, double-blind, placebo-controlled crossover study, we examined the effect of 250 μg nebulized fentanyl, chest wall strapping (CWS), and their interaction on detailed physiological and perceptual responses to constant work rate cycle exercise (85% of maximum incremental work rate) in 14 healthy, fit young men. By design, CWS decreased vital capacity by ∼20% and mimicked the negative consequences of a mild restrictive lung disorder on exercise endurance time and on dyspnea, breathing pattern, dynamic operating lung volumes, and diaphragmatic electromyographic and respiratory muscle function during exercise. Compared with placebo under both unrestricted control and CWS conditions, nebulized fentanyl had no effect on exercise endurance time, integrated physiological response to exercise, sensory intensity, unpleasantness ratings of exertional dyspnea. Our results do not support a role for intrapulmonary opioids in the neuromodulation of exertional dyspnea in health nor do they provide a physiological rationale for the use of nebulized fentanyl in the management of dyspnea due to mild restrictive lung disorders, specifically those arising from abnormalities of the chest wall and not affiliated with airway inflammation. PMID:26031762

  11. Torsional and biaxial (tension-torsion) fatigue damage mechanisms in Waspaloy at room temperature

    NASA Technical Reports Server (NTRS)

    Jayaraman, N.; Ditmars, M. M.

    1989-01-01

    Strain controlled torsional and biaxial (tension-torsion) low cycle fatigue behavior of Waspaloy was studied at room temperature as a function of heat treatment. Biaxial tests were conducted under proportional and nonproportional cyclic conditions. The deformation behavior under these different cyclic conditions was evaluated by slip trace analysis. For this, a Schmidt-type factor was defined for multiaxial loading conditions, and it was shown that when the slip deformation is predominant, nonproportional cycles are more damaging than proportional or pure axial or torsional cycles. This was attributed to the fact that under nonproportional cyclic conditions, deformation was through multiple slip, as opposed to single slip for other loading conditions, which gave rise to increased hardening. The total life for a given test condition was found to be independent of heat treatment. This was interpreted as being due to the differences in the cycles to initiation and propagation of cracks.

  12. Biothermal sensing of a torsional artificial muscle

    NASA Astrophysics Data System (ADS)

    Lee, Sung-Ho; Kim, Tae Hyeob; Lima, Márcio D.; Baughman, Ray H.; Kim, Seon Jeong

    2016-02-01

    Biomolecule responsive materials have been studied intensively for use in biomedical applications as smart systems because of their unique property of responding to specific biomolecules under mild conditions. However, these materials have some challenging drawbacks that limit further practical application, including their speed of response and mechanical properties, because most are based on hydrogels. Here, we present a fast, mechanically robust biscrolled twist-spun carbon nanotube yarn as a torsional artificial muscle through entrapping an enzyme linked to a thermally sensitive hydrogel, poly(N-isopropylacrylamide), utilizing the exothermic catalytic reaction of the enzyme. The induced rotation reached an equilibrated angle in less than 2 min under mild temperature conditions (25-37 °C) while maintaining the mechanical properties originating from the carbon nanotubes. This biothermal sensing of a torsional artificial muscle offers a versatile platform for the recognition of various types of biomolecules by replacing the enzyme, because an exothermic reaction is a general property accompanying a biochemical transformation.Biomolecule responsive materials have been studied intensively for use in biomedical applications as smart systems because of their unique property of responding to specific biomolecules under mild conditions. However, these materials have some challenging drawbacks that limit further practical application, including their speed of response and mechanical properties, because most are based on hydrogels. Here, we present a fast, mechanically robust biscrolled twist-spun carbon nanotube yarn as a torsional artificial muscle through entrapping an enzyme linked to a thermally sensitive hydrogel, poly(N-isopropylacrylamide), utilizing the exothermic catalytic reaction of the enzyme. The induced rotation reached an equilibrated angle in less than 2 min under mild temperature conditions (25-37 °C) while maintaining the mechanical properties

  13. Torsion-rotation intensities in methanol

    NASA Astrophysics Data System (ADS)

    Pearson, John

    Methanol exists in numerous kinds of astronomical objects featuring a wide range of local conditions. The light nature of the molecule coupled with the internal rotation of the methyl group with respect to the hydroxyl group results in a rich, strong spectrum that spans the entire far-infrared region. As a result, any modest size observational window will have a number of strong methanol transitions. This has made it the gas of choice for testing THz receivers and to extract the local physical conditions from observations covering small frequency windows. The latter has caused methanol to be dubbed the Swiss army knife of astrophysics. Methanol has been increasingly used in this capacity and will be used even more for subsequent investigations into the Herschel archive, and with SOFIA and ALMA. Interpreting physical conditions on the basis of a few methanol lines requires that the molecular data, line positions, intensities, and collision rates, be complete, consistent and accurate to a much higher level than previously required for astrophysics. The need for highly reliable data is even more critical for modeling the two classes of widespread maser action and many examples of optical pumping through the torsional bands. Observation of the torsional bands in the infrared will be a unique opportunity to directly connect JWST observations with those of Herschel, SOFIA, and ALMA. The theory for the intensities of torsion-rotation transitions in a molecule featuring a single internally rotating methyl group is well developed after 70 years of research. However, other than a recent very preliminary and not completely satisfactory investigation of a few CH3OH torsional bands, this theory has never been experimentally tested for any C3V internal rotor. More alarming is a set of recent intensity calibrated microwave measurements that showed deviations relative to calculations of up to 50% in some ground state rotational transitions commonly used by astronomers to extract

  14. Torsion discovery potential and its discrimination at CERN LHC

    SciTech Connect

    Almeida, F. M. L. Jr. de; Nepomuceno, A. A.; Vale, M. A. B. do

    2009-01-01

    Torsion models constitute a well-known class of extended quantum gravity models. In this paper we study some phenomenological consequences of a torsion field interacting with fermions at LHC. A torsion field could appear as a new heavy state characterized by its mass and couplings to fermions. These new states will form a resonance decaying into difermions, as occurs in many extensions of the standard model, such as models predicting the existence of additional neutral gauge bosons, usually named Z{sup '}. Using the dielectron channel we evaluate the integrated luminosity needed for a 5{sigma} discovery as a function of the torsion mass, for different coupling values. We also calculate the luminosity needed to discriminate, with 95% C.L., the two possible different torsion natures. Finally, we show that the observed signal coming from the torsion field could be distinguished from a signal coming from a new neutral gauge boson, provided there is enough luminosity.

  15. Can Gravity Probe B usefully constrain torsion gravity theories?

    SciTech Connect

    Flanagan, Eanna E.; Rosenthal, Eran

    2007-06-15

    In most theories of gravity involving torsion, the source for torsion is the intrinsic spin of matter. Since the spins of fermions are normally randomly oriented in macroscopic bodies, the amount of torsion generated by macroscopic bodies is normally negligible. However, in a recent paper, Mao et al. (arXiv:gr-qc/0608121) point out that there is a class of theories, including the Hayashi-Shirafuji (1979) theory, in which the angular momentum of macroscopic spinning bodies generates a significant amount of torsion. They further argue that, by the principle of action equals reaction, one would expect the angular momentum of test bodies to couple to a background torsion field, and therefore the precession of the Gravity Probe B gyroscopes should be affected in these theories by the torsion generated by the Earth. We show that in fact the principle of action equals reaction does not apply to these theories, essentially because the torsion is not an independent dynamical degree of freedom. We examine in detail a generalization of the Hayashi-Shirafuji theory suggested by Mao et al. called Einstein-Hayashi-Shirafuji theory. There are a variety of different versions of this theory, depending on the precise form of the coupling to matter chosen for the torsion. We show that, for any coupling to matter that is compatible with the spin transport equation postulated by Mao et al., the theory has either ghosts or an ill-posed initial-value formulation. These theoretical problems can be avoided by specializing the parameters of the theory and in addition choosing the standard minimal coupling to matter of the torsion tensor. This yields a consistent theory, but one in which the action equals reaction principle is violated, and in which the angular momentum of the gyroscopes does not couple to the Earth's torsion field. Thus, the Einstein-Hayashi-Shirafuji theory does not predict a detectable torsion signal for Gravity Probe B. There may be other torsion theories which do.

  16. Torsion-gravity for Dirac fields and their effective phenomenology

    NASA Astrophysics Data System (ADS)

    Fabbri, Luca

    2014-08-01

    We will consider the torsional completion of gravity for a background filled with Dirac matter fields, studying the weak-gravitational non-relativistic approximation, in view of an assessment about their effective phenomenology: we discuss how the torsionally-induced nonlinear interactions among fermion fields in this limit are compatible with all experiments and remarks on the role of torsion to suggest new physics are given.

  17. Ovarian torsion: opportunities to improve clinical management.

    PubMed

    Bharathan, R; Ramsawak, L; Kelly, A

    2012-10-01

    Ovarian torsion is an uncommon condition which may affect women of any age. In a significant number of women, it may be associated with a concomitant pathology such as a cyst. Presently, there is no single diagnostic tool with significant predictive value. Multimodal diagnostic tools hold promise of early accurate diagnosis; prospective studies are required to assess the validity of such tools. This would enable wider application of ovarian function preserving procedures. Further, an assessment of the psychological impact of oophorectomy should be studied in order to facilitate the optimal tailored care. PMID:22943718

  18. Aspects of Interacting Electromagnetic and Torsion Fields

    NASA Astrophysics Data System (ADS)

    Gaete, Patricio; Helaÿel-Neto, José A.

    2011-01-01

    The interaction energy is studied for the coupling of axial torsion fields with photons in the presence of an external electromagnetic field. To this end, we compute the static quantum potential. Our discussion is carried out using the gauge-invariant but path-dependent variables formalism, which is alternative to the Wilson loop approach. Our results show that the static potential is a Yukawa correction to the usual static Coulomb potential. Interestingly, when this calculation is done by considering a mass term for the gauge field, the Coulombic piece disappears leading to a screening phase.

  19. The Torsional Spectrum of Doubly Deuterated Methanol CHD_2OH

    NASA Astrophysics Data System (ADS)

    Ndao, M.; Coudert, L. H.; Kwabia Tchana, F.; Barros, J.; Margulès, L.; Manceron, Laurent; Roy, P.

    2014-06-01

    Although the torsional spectrum of several isotopic species of methanol with a symmetrical CH_3 or CD_3 was analyzed some time ago, it is recently, and only for the monodeuterated species CH_2DOH, that such an analysis was extended to the case of an asymmetrical methyl group. In this talk, based on a Fourier transform high-resolution spectrum recorded in the 20 to 670 wn region, the first analysis of the torsional spectrum of doubly deuterated methanol CHD_2OH will be presented. The Q branch of many torsional subbands could be observed and their assignment was initiated using a theoretical torsion-rotation spectrum computed with an approach accounting for the torsion-rotation Coriolis coupling and for the dependence of the generalized inertia tensor on the angle of internal rotation. 46 torsional subbands were thus assigned. For 28 of them, their rotational structure could be assigned and fitted using an effective Hamiltonian expressed as a J(J+1) expansion; and for 2 of them microwave transitions within the lower torsional level could also be included in the analysis. In several cases these analysis revealed that the torsional levels are strongly perturbed. In the talk, the torsional parameters retrieved in the analysis of the torsional subband centers will be discussed. The results of the analysis of the rotational structure of the torsional subbands will be presented and we will also try to understand the nature of the perturbations. At last, preliminary results about the analysis of the microwave spectrum will be presented. El Hilali, Coudert, Konov, and Klee, J. Chem. Phys. 135 (2011) 194309 Lauvergnat, Coudert, Klee, and Smirnov, J. Mol. Spectrosc. 256 (2009) 204 Quade, Liu, Mukhopadhyay, and Su, J. Mol. Spectrosc. 192 (1998) 378 Pearson, Yu, and Drouin, J. Mol. Spectrosc. 280 (2012) 119

  20. Activation of Corticostriatal Circuitry Relieves Chronic Neuropathic Pain

    PubMed Central

    Lee, Michelle; Manders, Toby R.; Eberle, Sarah E.; Su, Chen; D'amour, James; Yang, Runtao; Lin, Hau Yueh; Deisseroth, Karl; Froemke, Robert C.

    2015-01-01

    Neural circuits that determine the perception and modulation of pain remain poorly understood. The prefrontal cortex (PFC) provides top-down control of sensory and affective processes. While animal and human imaging studies have shown that the PFC is involved in pain regulation, its exact role in pain states remains incompletely understood. A key output target for the PFC is the nucleus accumbens (NAc), an important component of the reward circuitry. Interestingly, recent human imaging studies suggest that the projection from the PFC to the NAc is altered in chronic pain. The function of this corticostriatal projection in pain states, however, is not known. Here we show that optogenetic activation of the PFC produces strong antinociceptive effects in a rat model (spared nerve injury model) of persistent neuropathic pain. PFC activation also reduces the affective symptoms of pain. Furthermore, we show that this pain-relieving function of the PFC is likely mediated by projections to the NAc. Thus, our results support a novel role for corticostriatal circuitry in pain regulation. PMID:25834050

  1. Emergency pulpotomy in relieving acute dental pain among Tanzanian patients

    PubMed Central

    Nyerere, Joachim W; Matee, Mecky I; Simon, Elison NM

    2006-01-01

    Background In Tanzania, oral health services are mostly in the form of dental extractions aimed at alleviating acute dental pain. Conservative methods of alleviating acute dental pain are virtually non-existent. Therefore, it was the aim of this study to determine treatment success of emergency pulpotomy in relieving acute dental pain. Methods Setting: School of Dentistry, Muhimbili National Hospital, Dar es Salaam, Tanzania. Study design: Longitudinal study. Participants: 180 patients who presented with dental pain due to acute irreversible pulpitis during the study period between July and August 2001. Treatment and evaluation: Patients were treated by emergency pulpotomy on permanent posterior teeth and were evaluated for pain after one, three and six week's post-treatment. Pain, if present, was categorised as either mild or acute. Results Of the patients with treated premolars, 25 (13.9%) patients did not experience pain at all while 19 (10.6%) experienced mild pain. None of the patients with treated premolars experienced acute pain. Among 136 patients with treated molars 56 (31%) did not experience any pain, 76 (42.2%) experienced mild pain and the other 4 (2.2%) suffered acute pain. Conclusion The short term treatment success of emergency pulpotomy was high being 100% for premolars and 97.1% for molars, suggesting that it can be recommended as a measure to alleviate acute dental pain while other conservative treatment options are being considered. PMID:16426455

  2. Relieving pain using dose-extending placebos: a scoping review.

    PubMed

    Colloca, Luana; Enck, Paul; DeGrazia, David

    2016-08-01

    Placebos are often used by clinicians, usually deceptively and with little rationale or evidence of benefit, making their use ethically problematic. In contrast with their typical current use, a provocative line of research suggests that placebos can be intentionally exploited to extend analgesic therapeutic effects. Is it possible to extend the effects of drug treatments by interspersing placebos? We reviewed a database of placebo studies, searching for studies that indicate that placebos given after repeated administration of active treatments acquire medication-like effects. We found a total of 22 studies in both animals and humans hinting of evidence that placebos may work as a sort of dose extender of active painkillers. Wherever effective in relieving clinical pain, such placebo use would offer several advantages. First, extending the effects of a painkiller through the use of placebos may reduce total drug intake and side effects. Second, dose-extending placebos may decrease patient dependence. Third, using placebos along with active medication, for part of the course of treatment, should limit dose escalation and lower costs. Provided that nondisclosure is preauthorized in the informed consent process and that robust evidence indicates therapeutic benefit comparable to that of standard full-dose therapeutic regimens, introducing dose-extending placebos into the clinical arsenal should be considered. This novel prospect of placebo use has the potential to change our general thinking about painkiller treatments, the typical regimens of painkiller applications, and the ways in which treatments are evaluated. PMID:27023425

  3. Relieving patients' pain with expectation interventions: a meta-analysis.

    PubMed

    Peerdeman, Kaya J; van Laarhoven, Antoinette I M; Keij, Sascha M; Vase, Lene; Rovers, Maroeska M; Peters, Madelon L; Evers, Andrea W M

    2016-06-01

    Patients' expectations are important predictors of the outcome of analgesic treatments, as demonstrated predominantly in research on placebo effects. Three commonly investigated interventions that have been found to induce expectations (verbal suggestion, conditioning, and mental imagery) entail promising, brief, and easy-to-implement adjunctive procedures for optimizing the effectiveness of analgesic treatments. However, evidence for their efficacy stems mostly from research on experimentally evoked pain in healthy samples, and these findings might not be directly transferable to clinical populations. The current meta-analysis investigated the effects of these expectation inductions on patients' pain relief. Five bibliographic databases were systematically searched for studies that assessed the effects of brief verbal suggestion, conditioning, or imagery interventions on pain in clinical populations, with patients experiencing experimental, acute procedural, or chronic pain, compared with no treatment or control treatment. Of the 15,955 studies retrieved, 30 met the inclusion criteria, of which 27 provided sufficient data for quantitative analyses. Overall, a medium-sized effect of the interventions on patients' pain relief was observed (Hedges g = 0.61, I = 73%), with varying effects of verbal suggestion (k = 18, g = 0.75), conditioning (always paired with verbal suggestion, k = 3, g = 0.65), and imagery (k = 6, g = 0.27). Subset analyses indicated medium to large effects on experimental and acute procedural pain and small effects on chronic pain. In conclusion, patients' pain can be relieved with expectation interventions; particularly, verbal suggestion for acute procedural pain was found to be effective. PMID:26945235

  4. New pain-relieving strategies for topical photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Halldin, Christina B.; Paoli, John; Sandberg, Carin; Ericson, Marica B.; Gonzalez, Helena; Wennberg, Ann-Marie

    2009-06-01

    PDT is an effective method when treating multiple actinic keratoses (field cancerization). The major side effect is pain. Our objectives were to investigate the pain-relieving effect of transcutaneous electrical nerve stimulation (TENS) and peripheral nerve blocks during PDT of field cancerization (FC) of the face and scalp. Patients with field cancerization were included in three studies. In the first study, we examined TENS with an application site on the adjacent dermatome from the PDT area in order to allow the use of water spray during PDT for FC of the scalp and face. In the second study, patients with FC in the facial area received unilateral supraorbital, infraorbital and/or mental nerve blocks. The non-anaesthetised side of the treatment area served as control. In the third study, with similar methodology as in the second study, occipital and supraorbital nerve blocks were combined for FC of the forehead and scalp. The results of the studies strongly support the use of nerve blocks as pain relief during PDT. The use of TENS provided a limited pain reduction, but TENS might be an alternative if the patient disapproves of the use of nerve blocks or is afraid of injections.

  5. Diagnostic Efficacy of Sonography for Diagnosis of Ovarian Torsion

    PubMed Central

    Rostamzadeh, Ayoob; Mirfendereski, Sam; Rezaie, Mohammad Jafar; Rezaei, Shohreh

    2014-01-01

    Objectives: Misdiagnosing ovarian torsion is now suggested as an important issue in clinical setting. The aim of this study was to determine the diagnostic accuracy of sonography for ovarian torsion. Methods : In this study 323 women with acute pelvic pain with highly suspected ovarian torsion signs and symptoms attending Imam Reza Medical Center in Kermanshah between 2011 through 2012 were included and underwent a transabdominal sonography (2-5 MHz probes). Then findings of sonography were compared with laparatomy. Results : The ultrasound correctly diagnosed 72.1% of ovarian torsion and missed 27.9% of them (false negatives). However, one free subject (0.4%) was misclassified as ovarian torsion (false positive). There was a strong correlation between sonography and laparatomy with a kappa value of 84.0%. The sensitivity and specificity of sonography were 72.1% and 99.6%, respectively. Sonography had a positive predictive value of 96.9%, a negative predictive value of 95.9%, and a total accuracy of 96.0% for detection of ovarian torsion. Conclusion: Sonography appears to be an excellent method to evaluate patients with suspected ovarian torsion. Abnormal blood flow detected by sonography is highly predictive of ovarian torsion and is therefore useful in the diagnosis of this phenomenon. PMID:24772154

  6. Torsional Strengthening of RC Beams Using GFRP Composites

    NASA Astrophysics Data System (ADS)

    Patel, Paresh V.; Jariwala, Vishnu H.; Purohit, Sharadkumar P.

    2016-06-01

    Fiber reinforced polymer as an external reinforcement is used extensively for axial, flexural and shear strengthening in structural systems. The strengthening of members subjected to torsion is recently being explored. The loading mechanism of beams located at the perimeter of buildings which carry loads from slabs, joists and beams from one side of the member generates torsion that are transferred from the beams to the columns. In this work an experimental investigation on the improvement of the torsional resistance of reinforced concrete beams using Glass Fiber Reinforced Polymer (GFRP) is presented. Total 24 RC beams have been cast in this work. Ten beams of dimension 150 mm × 150 mm × 1300 mm are subjected to pure torsion while fourteen beams of 150 mm × 150 mm × 1700 mm are subjected to combined torsion and bending. Two beams in each category are designated as control specimen and remaining beams are strengthened by GFRP wrapping of different configurations. Pure torsion on specimens is applied using specially fabricated support mechanism and universal testing machine. For applying combined torsion and bending a loading frame and test set up are fabricated. Measurements of angle of twist at regular interval of torque, torsion at first crack, and ultimate torque, are obtained for all specimens. Results of different wrapping configurations are compared for control and strengthened beams to suggest effective GFRP wrapping configuration.

  7. Analysis of interlaminar stresses in the torsion of symmetric laminates

    NASA Astrophysics Data System (ADS)

    Whitney, James M.

    1994-03-01

    In the present paper the effect of transverse (interlaminar) normal strain on the torsional response of symmetrically laminated, anisotropic plates is investigated. The analysis is based on a modified form of the global laminate model developed by Pagano and Soni. In-plane stresses are modified in the boundary zone to satisfy free-edge boundary conditions. For the general case of angle-ply layers, a laminated composite behaves in a manner similar to an anisotropic plate. The existence of the bending-twisting coupling phenomenon found in the case of anisotropic plates leads to two classic problems in conjunction with torsional loading. In the first case, referred to as 'pure torsion,' the torsional axis of the plates does not bend. Thus, an axial bending moment is required in addition to the torsional load to suppress plate bending. In the second case, referred to as 'free torsion,' the only loading is torque in which anisotropy induces bending of the torsional axis. For the purposes of this paper it is sufficient to consider the case of pure torsion only.

  8. Two Cases of Omental Torsion Mimicking Acute Appendicitis

    PubMed Central

    Liaqat, Naeem; Dar, Sajid Hameed; Sandhu, Asif Iqbal; Nayyer, Sajid

    2014-01-01

    Acute appendicitis is often simulated by other entities like mesenteric adenitis, worm infestation, Meckel’s diverticulitis, urinary tract infection and rarely omental torsion. We report two cases, a 6 year old boy and an 11 year old girl, who presented with symptoms and signs of acute appendicitis but upon exploration turned out to be omental torsion. PMID:24834389

  9. Hydrostatic self-aligning axial/torsional mechanism

    DOEpatents

    O'Connor, Daniel G.; Gerth, Howard L.

    1990-01-01

    The present invention is directed to a self-aligning axial/torsional loading mechanism for testing the strength of brittle materials which are sensitive to bending moments. Disposed inside said self-aligning loading mechanism is a frictionless hydrostatic ball joint with a flexure ring to accommodate torsional loads through said ball joint.

  10. Mechanical origins of rightward torsion in early chick brain development

    NASA Astrophysics Data System (ADS)

    Chen, Zi; Guo, Qiaohang; Dai, Eric; Taber, Larry

    2015-03-01

    During early development, the neural tube of the chick embryo undergoes a combination of progressive ventral bending and rightward torsion. This torsional deformation is one of the major organ-level left-right asymmetry events in development. Previous studies suggested that bending is mainly due to differential growth, however, the mechanism for torsion remains poorly understood. Since the heart almost always loops rightwards that the brain twists, researchers have speculated that heart looping affects the direction of brain torsion. However, direct evidence is lacking, nor is the mechanical origin of such torsion understood. In our study, experimental perturbations show that the bending and torsional deformations in the brain are coupled and that the vitelline membrane applies an external load necessary for torsion to occur. Moreover, the asymmetry of the looping heart gives rise to the chirality of the twisted brain. A computational model and a 3D printed physical model are employed to help interpret these findings. Our work clarifies the mechanical origins of brain torsion and the associated left-right asymmetry, and further reveals that the asymmetric development in one organ can induce the asymmetry of another developing organ through mechanics, reminiscent of D'Arcy Thompson's view of biological form as ``diagram of forces''. Z.C. is supported by the Society in Science - Branco Weiss fellowship, administered by ETH Zurich. L.A.T acknowledges the support from NIH Grants R01 GM075200 and R01 NS070918.

  11. Fertility after oophorectomy due to torsion

    PubMed Central

    Al-Turki, Haifa A.

    2015-01-01

    Objectives: To investigate the prevalence of infertility in patients who underwent salpingo-oophorectomy due to adnexal torsion (AT). Methods: All adult women admitted to the Teaching Institution of the University of Dammam, Dammam, Saudi Arabia who underwent surgery due to AT between January 2001 and 2010 were included. Complete data was collected from the time of admission to the follow up. The data was entered into the database and analyzed. Results: The data of 26 patients was available for analysis. The mean age (±standard deviation) at presentation was 22.19±4.4 years, and average age at follow up was 34.81±5.75 years. The average delay in presentation was 37.76±47 hours, and the surgery was performed at 45.07±48.57 hours. The right side was involved in 13 (53.8%) of the cases. Fourteen (53.9%) women presented with infertility. Eleven (78.57%) were treated for infertility, and 5 (45.5%) conceived. Patients who were younger at the time of torsion fared better with regard to pregnancy (p<0.03, 95% confidence interval:-6.85; <0.58). Conclusion: Patients who undergo salpingo-oophorectomy for AT have an increased risk of infertility and should be warned of this impending complication. PMID:25737184

  12. Infrared modified gravity with dynamical torsion

    NASA Astrophysics Data System (ADS)

    Nikiforova, V.; Randjbar-Daemi, S.; Rubakov, V.

    2009-12-01

    We continue the recent study of the possibility of constructing a consistent infrared modification of gravity by treating the vierbein and connection as independent dynamical fields. We present the generalized Fierz-Pauli equation that governs the propagation of a massive spin-2 mode in a model of this sort in the backgrounds of arbitrary torsionless Einstein manifolds. We show explicitly that the number of propagating degrees of freedom in these backgrounds remains the same as in flat space-time. This generalizes the recent result that the Boulware-Deser phenomenon does not occur in de Sitter and anti-de Sitter backgrounds. We find that, at least for weakly curved backgrounds, there are no ghosts in the model. We also discuss the interaction of sources in flat background. It is generally believed that the spinning matter is the only source of torsion. Our flat space study shows that this is not the case. We demonstrate that an ordinary conserved symmetric energy-momentum tensor can also generate torsion fields and thus excite massive spin-2 degrees of freedom.

  13. Curvature and torsion in growing actin networks

    NASA Astrophysics Data System (ADS)

    Shaevitz, Joshua W.; Fletcher, Daniel A.

    2008-06-01

    Intracellular pathogens such as Listeria monocytogenes and Rickettsia rickettsii move within a host cell by polymerizing a comet-tail of actin fibers that ultimately pushes the cell forward. This dense network of cross-linked actin polymers typically exhibits a striking curvature that causes bacteria to move in gently looping paths. Theoretically, tail curvature has been linked to details of motility by considering force and torque balances from a finite number of polymerizing filaments. Here we track beads coated with a prokaryotic activator of actin polymerization in three dimensions to directly quantify the curvature and torsion of bead motility paths. We find that bead paths are more likely to have low rather than high curvature at any given time. Furthermore, path curvature changes very slowly in time, with an autocorrelation decay time of 200 s. Paths with a small radius of curvature, therefore, remain so for an extended period resulting in loops when confined to two dimensions. When allowed to explore a three-dimensional (3D) space, path loops are less evident. Finally, we quantify the torsion in the bead paths and show that beads do not exhibit a significant left- or right-handed bias to their motion in 3D. These results suggest that paths of actin-propelled objects may be attributed to slow changes in curvature, possibly associated with filament debranching, rather than a fixed torque.

  14. Torsion and transverse sensing of conical shells

    NASA Astrophysics Data System (ADS)

    Li, H.; Chen, Z. B.; Tzou, H. S.

    2010-10-01

    Conical shells are widely used as payload/rocket adapters in rocket fairing systems. Generally, the conical shells are clamped at the major end and free at the minor end, where the payload is mounted. This study focuses on the dynamic sensing of conical shells with fix-free boundary conditions (BCs) by using distributed piezoelectric helical sensors. Two types of motion are studied, i.e., the transverse modes and the torsion modes. The shear-type sensors for shells sensing are presented first. Formulations of sensing signals of a general shell of revolution are presented, and then simplified to conical shells. For sensing of transverse vibrations, thin piezoelectric sensors are laminated on the top surface. Two types of sensor distribution are considered: a fully distributed and a helical or diagonal laminated. The total signal consists of four components resulting from the four strain components, and each of them is evaluated in detail. For sensing of torsion vibrations, a meridional polarized shear-type sensor with side electrodes is layered on the top surface of the shell structure. Sensing signals of natural shell modes are also evaluated. Analyses show that, in low order modes, the sensing signals induced by the circumferential membrane strains are the primary components of the total signal generations. The numerical results indicate the optimal location of the sensors. The proposed method is capable of determining the modal participation factors, while the testing signal is available; it is also capable of determining the mode shapes by using several distributed sensor segments.

  15. Biothermal sensing of a torsional artificial muscle.

    PubMed

    Lee, Sung-Ho; Kim, Tae Hyeob; Lima, Márcio D; Baughman, Ray H; Kim, Seon Jeong

    2016-02-14

    Biomolecule responsive materials have been studied intensively for use in biomedical applications as smart systems because of their unique property of responding to specific biomolecules under mild conditions. However, these materials have some challenging drawbacks that limit further practical application, including their speed of response and mechanical properties, because most are based on hydrogels. Here, we present a fast, mechanically robust biscrolled twist-spun carbon nanotube yarn as a torsional artificial muscle through entrapping an enzyme linked to a thermally sensitive hydrogel, poly(N-isopropylacrylamide), utilizing the exothermic catalytic reaction of the enzyme. The induced rotation reached an equilibrated angle in less than 2 min under mild temperature conditions (25-37 °C) while maintaining the mechanical properties originating from the carbon nanotubes. This biothermal sensing of a torsional artificial muscle offers a versatile platform for the recognition of various types of biomolecules by replacing the enzyme, because an exothermic reaction is a general property accompanying a biochemical transformation. PMID:26806884

  16. Infrared modified gravity with dynamical torsion

    SciTech Connect

    Nikiforova, V.; Randjbar-Daemi, S.; Rubakov, V.

    2009-12-15

    We continue the recent study of the possibility of constructing a consistent infrared modification of gravity by treating the vierbein and connection as independent dynamical fields. We present the generalized Fierz-Pauli equation that governs the propagation of a massive spin-2 mode in a model of this sort in the backgrounds of arbitrary torsionless Einstein manifolds. We show explicitly that the number of propagating degrees of freedom in these backgrounds remains the same as in flat space-time. This generalizes the recent result that the Boulware-Deser phenomenon does not occur in de Sitter and anti-de Sitter backgrounds. We find that, at least for weakly curved backgrounds, there are no ghosts in the model. We also discuss the interaction of sources in flat background. It is generally believed that the spinning matter is the only source of torsion. Our flat space study shows that this is not the case. We demonstrate that an ordinary conserved symmetric energy-momentum tensor can also generate torsion fields and thus excite massive spin-2 degrees of freedom.

  17. Torsion and noninertial effects on a nonrelativistic Dirac particle

    SciTech Connect

    Bakke, K.

    2014-07-15

    We investigate torsion and noninertial effects on a spin-1/2 quantum particle in the nonrelativistic limit of the Dirac equation. We consider the cosmic dislocation spacetime as a background and show that a rotating system of reference can be used out to distances which depend on the parameter related to the torsion of the defect. Therefore, we analyse torsion effects on the spectrum of energy of a nonrelativistic Dirac particle confined to a hard-wall potential in a Fermi–Walker reference frame. -- Highlights: •Torsion effects on a spin- 1/2 particle in a noninertial reference frame. •Fermi–Walker reference frame in the cosmic dislocation spacetime background. •Torsion and noninertial effects on the confinement to a hard-wall confining potential.

  18. Torsion angle preferences in druglike chemical space: a comprehensive guide.

    PubMed

    Schärfer, Christin; Schulz-Gasch, Tanja; Ehrlich, Hans-Christian; Guba, Wolfgang; Rarey, Matthias; Stahl, Martin

    2013-03-14

    Crystal structure databases offer ample opportunities to derive small molecule conformation preferences, but the derived knowledge is not systematically applied in drug discovery research. We address this gap by a comprehensive and extendable expert system enabling quick assessment of the probability of a given conformation to occur. It is based on a hierarchical system of torsion patterns that cover a large part of druglike chemical space. Each torsion pattern has associated frequency histograms generated from CSD and PDB data and, derived from the histograms, traffic-light rules for frequently observed, rare, and highly unlikely torsion ranges. Structures imported into the corresponding software are annotated according to these rules. We present the concept behind the tree of torsion patterns, the design of an intuitive user interface for the management and usage of the torsion library, and we illustrate how the system helps analyze and understand conformation properties of substructures widely used in medicinal chemistry. PMID:23379567

  19. Tailoring patterns of graphene wrinkles by circular torsion

    NASA Astrophysics Data System (ADS)

    Becton, Matthew; Wang, Xianqiao

    2016-02-01

    Wrinkled graphene has been emerging as a hot topic of interest due to its easily induced physical changes accompanied by changes in its material behavior. However, the wrinkling pattern of graphene and its relevant properties remain poorly understood. Here we employ molecular dynamics simulations to model the behavior of graphene under periodic, torsional wrinkling and elucidate the effect of torsion pattern, torsion velocity, and hole size on the wrinkling characteristics of a large graphene sheet. Simulation results show that gross control over the wrinkling pattern is feasible via manipulation of torsion direction and relative hole size, with fine-tuning of the wrinkle formation possible by control of the relative torsion speed of each hole.

  20. Torsional ARC Effectively Expands the Visual Field in Hemianopia

    PubMed Central

    Satgunam, PremNandhini; Peli, Eli

    2012-01-01

    Purpose Exotropia in congenital homonymous hemianopia has been reported to provide field expansion that is more useful when accompanied with harmonios anomalous retinal correspondence (HARC). Torsional strabismus with HARC provides a similar functional advantage. In a subject with hemianopia demonstrating a field expansion consistent with torsion we documented torsional strabismus and torsional HARC. Methods Monocular visual fields under binocular fixation conditions were plotted using a custom dichoptic visual field perimeter (DVF). The DVF was also modified to measure perceived visual directions under dissociated and associated conditions across the central 50° diameter field. The field expansion and retinal correspondence of a subject with torsional strabismus (along with exotropia and right hypertropia) with congenital homonymous hemianopia was compared to that of another exotropic subject with acquired homonymous hemianopia without torsion and to a control subject with minimal phoria. Torsional rotations of the eyes were calculated from fundus photographs and perimetry. Results Torsional ARC documented in the subject with congenital homonymous hemianopia provided a functional binocular field expansion up to 18°. Normal retinal correspondence was mapped for the full 50° visual field in the control subject and for the seeing field of the acquired homonymous hemianopia subject, limiting the functional field expansion benefit. Conclusions Torsional strabismus with ARC, when occurring with homonymous hemianopia provides useful field expansion in the lower and upper fields. Dichoptic perimetry permits documentation of ocular alignment (lateral, vertical and torsional) and perceived visual direction under binocular and monocular viewing conditions. Evaluating patients with congenital or early strabismus for HARC is useful when considering surgical correction, particularly in the presence of congenital homonymous hemianopia. PMID:22885782

  1. [The effect of DNA supercoiling DNA on nucleosome structure].

    PubMed

    Sivolob, A V; Khrapunov, S N

    1991-01-01

    The circular DNA which contains nucleosomes and additional supercoils has been considered theoretically. The different possible effect of increased negative supercoiling on the nucleosome structure have been studied. According to the model proposed all supercoils in the nucleosome-containing circular DNA are realized as torsional deformations of the double helix. The free energy of both supercoiling (torsional deformations) and nucleosome stabilization have been taken into consideration to obtain the equation for free energy of nucleosome-containing circular DNA. The analysis of this equation and the experimental data by Garner et al. (II Psoc. Natl. Acad. Sci. USA. 1987. P. 2620-2623) about the maximum amount of supercoiling obtained by DNA-topoisomerase II treatment of nucleosome-containing pBR322 plasmid has been performed. It has been shown that two possibilities are consistent with both the equation and experimental data. These are: (1) the increased supercoiling induces the torsional strains not only in linker regions but also in nucleosome DNA and thus supercoiling causes an instability on nucleosome structure; (2) increased supercoiling induces a structural change of nucleosome which is accompanied by nucleosome DNA unwinding and its transition into form with approximately 11 base pairs per turn of double helix. It has been evaluated that in the first case the average torsional rigidity of nucleosome DNA should be approximately 2.5 times as much and in the second case--much more than the rigidity of naked DNA. Both types of nucleosome structural changes may cause its transition to a potentially active state for transcription. It is suggested that increased supercoiling can be a switch mechanism of chromatin activation. PMID:1654518

  2. The management of moderate and severe congenital penile torsion associated with hypospadias: Urethral mobilisation is not a panacea against torsion

    PubMed Central

    Elbakry, Adel; Zakaria, Ahmed; Matar, Adel; El Nashar, Ahmed

    2013-01-01

    Objectives To evaluate the effectiveness of urethral mobilisation for correcting moderate and severe penile torsion associated with distal hypospadias. Patients and methods Nineteen patients with distal hypospadias and congenital moderate and severe penile torsion were treated surgically. The hypospadias was at the distal shaft, coronal and glanular in seven, eight and four patients, respectively, and six had mild chordee. The mean (SD, range) angle of torsion was 94.7 (19.9, 75–160)°. The urethra was mobilised down to the perineum. If the urethral mobilisation was insufficient the right border of the tunica albuginea was anchored to the pubic periosteum. The hypospadias was repaired using the urethral mobilisation and advancement technique, with a triangular plate flap for meatoplasty. The patients were followed up for 12–18 months. Results All patients had a successful functional and cosmetic outcome, with no residual torsion. Two patients had a small subcutaneous haematoma that resolved after conservative treatment. Massive oedema occurred in three patients and was treated conservatively. Urethral mobilisation did not correct the penile torsion completely. Although the mean (SD, range) angle of torsion was reduced to 86.1 (14.3, 65–130)°, statistically significantly different (P = 0.001), it was not clinically important. The presence of chordee had no significant correlation with the reduction of penile torsion. Conclusion Urethral mobilisation cannot completely correct moderate and severe penile torsion but it might only partly decrease the angle of torsion. Periosteal anchoring of the tunica albuginea might be the most reliable manoeuvre for the complete correction of penile torsion. PMID:26579237

  3. Torsional actuation with extension-torsion composite coupling and a magnetostrictive actuator

    NASA Astrophysics Data System (ADS)

    Bothwell, Christopher M.; Chandra, Ramesh; Chopra, Inderjit

    1995-04-01

    An analytical-experimental study of using magnetostrictive actuators in conjunction with an extension-torsion coupled composite tube to actuate a rotor blade trailing-edge flap to actively control helicopter vibration is presented. Thin walled beam analysis based on Vlasov theory was used to predict the induced twist and extension in a composite tube with magnetostrictive actuation. The study achieved good correlation between theory and experiment. The Kevlar-epoxy systems showed good correlation between measured and predicted twist values.

  4. Torsional suspension system for testing space structures

    NASA Technical Reports Server (NTRS)

    Reed, Wilmer H., III (Inventor); Gold, Ronald R. (Inventor)

    1991-01-01

    A low frequency torsional suspension system for testing a space structure uses a plurality of suspension stations attached to the space structure along the length thereof in order to suspend the space structure from an overhead support. Each suspension station includes a disk pivotally mounted to the overhead support, and two cables which have upper ends connected to the disk and lower ends connected to the space structure. The two cables define a parallelogram with the center of gravity of the space structure being vertically beneath the pivot axis of the disk. The vertical distance between the points of attachment of the cables to the disk and the pivot axis of the disk is adjusted to lower the frequency of the suspension system to a level which does not interfere with frequency levels of the space structure, thereby enabling accurate measurement.

  5. Torsion Balance Test of Einstein's Equivalence Principle

    NASA Astrophysics Data System (ADS)

    Abercrombie, Michael; Archibald, Adam; Nussinov, Tsitsi; Wagoner, Kasey; Cowsik, Ramanath

    2016-03-01

    We have developed a torsion balance experiment to test the equivalence principle (EP) which follows the solar attractor approach pioneered by Dicke in the early 1960s. By monitoring the response of a balance arranged as a composition dipole with an azimuthally symmetric mass distribution to the gravitational field produced by the Sun, we search for a diurnal modulation of the balance which would indicate a violation of the EP. Since reporting on the status of this experiment last year, the instrument has begun collecting data at a remote underground site. This talk will cover the design and fundamental sensitivity of the balance, and present the results of preliminary analysis of over 1200 hours of data.

  6. Torsion Tests of Stiffened Circular Cylinders

    NASA Technical Reports Server (NTRS)

    Moore, R L; Wescoat, C

    1944-01-01

    The design of curved sheet panels to resist shear involves a consideration of several factors: the buckling resistance of the sheet, the stress at which buckling becomes permanent, and the strength which may be developed beyond the buckling limit by tension-field action. Although some experimental as well as theoretical work has been done on the buckling and tension-field phases of this problem, neither of these types of action appears to be very well understood. The problem is of sufficient importance from the standpoint of aircraft design, it is believed, to warrant further experimental investigation. This report presents the results of the first series of torsion tests of stiffened circular cylinders to be completed in connection with this study at Aluminum Research Laboratories. (author)

  7. Plant-based torsional actuator with memory

    NASA Astrophysics Data System (ADS)

    Plaza, Nayomi; Zelinka, Samuel L.; Stone, Don S.; Jakes, Joseph E.

    2013-07-01

    A bundle of a few loblolly pine (Pinus taeda) cells are moisture-activated torsional actuators that twist multiple revolutions per cm length in direct proportion to moisture content. The bundles generate 10 N m kg-1 specific torque during both twisting and untwisting, which is higher than an electric motor. Additionally, the bundles exhibit a moisture-activated, shape memory twist effect. Over 70% of the twist in a wetted bundle can be locked-in by drying under constraint and then released by rewetting the bundle. Our results indicate that hemicelluloses dominate the shape fixity mechanism and lignin is primarily responsible for remembering the bundle’s original form. The bundles demonstrate proof of a high specific torque actuator with large angles of rotation and shape memory twist capabilities that can be used in microactuators, sensors, and energy harvesters.

  8. Combined bending-torsion fatigue reliability. III

    NASA Technical Reports Server (NTRS)

    Kececioglu, D.; Chester, L. B.; Nolf, C. F., Jr.

    1975-01-01

    Results generated by three, unique fatigue reliability research machines which can apply reversed bending loads combined with steady torque are presented. AISI 4340 steel, grooved specimens with a stress concentration factor of 1.42 and 2.34, and Rockwell C hardness of 35/40 were subjected to various combinations of these loads and cycled to failure. The generated cycles-to-failure and stress-to-failure data are statistically analyzed to develop distributional S-N and Goodman diagrams. Various failure theories are investigated to determine which one represents the data best. The effects of the groove, and of the various combined bending-torsion loads, on the S-N and Goodman diagrams are determined. Two design applications are presented which illustrate the direct useability and value of the distributional failure governing strength and cycles-to-failure data in designing for specified levels of reliability and in predicting the reliability of given designs.

  9. Experimental Study of Torsional Column Failure

    NASA Technical Reports Server (NTRS)

    Nile, Alfred S

    1939-01-01

    Thirty-three 24ST aluminum-alloy 2- by 2- by 0.10-inch channels, with lengths ranging from 10 to 90 inches were tested at Stanford University in compression to obtain an experimental verification of the theoretical formulas for torsional failure developed by Eugene E. Lundquist of the N.A.C.A. The observed critical loads and twist-axis locations were sufficiently close to the values obtained from the formulas to establish the substantial validity of the latter. The differences between observed and computed results were small enough to be accounted for by small and mostly unavoidable differences between actual test conditions and those assumed in deriving the formulas. Some data were obtained from the shorter specimens regarding the growth of the buckles that resulted in local buckling failure.

  10. Torsional ultrasonic transducer computational design optimization.

    PubMed

    Melchor, J; Rus, G

    2014-09-01

    A torsional piezoelectric ultrasonic sensor design is proposed in this paper and computationally tested and optimized to measure shear stiffness properties of soft tissue. These are correlated with a number of pathologies like tumors, hepatic lesions and others. The reason is that, whereas compressibility is predominantly governed by the fluid phase of the tissue, the shear stiffness is dependent on the stroma micro-architecture, which is directly affected by those pathologies. However, diagnostic tools to quantify them are currently not well developed. The first contribution is a new typology of design adapted to quasifluids. A second contribution is the procedure for design optimization, for which an analytical estimate of the Robust Probability Of Detection, called RPOD, is presented for use as optimality criteria. The RPOD is formulated probabilistically to maximize the probability of detecting the least possible pathology while minimizing the effect of noise. The resulting optimal transducer has a resonance frequency of 28 kHz. PMID:24882020

  11. Constraining spacetime torsion with the Moon and Mercury

    SciTech Connect

    March, Riccardo; Bellettini, Giovanni; Tauraso, Roberto; Dell'Agnello, Simone

    2011-05-15

    We report a search for new gravitational physics phenomena based on Riemann-Cartan theory of general relativity including spacetime torsion. Starting from the parametrized torsion framework of Mao, Tegmark, Guth, and Cabi, we analyze the motion of test bodies in the presence of torsion, and, in particular, we compute the corrections to the perihelion advance and to the orbital geodetic precession of a satellite. We consider the motion of a test body in a spherically symmetric field, and the motion of a satellite in the gravitational field of the Sun and the Earth. We describe the torsion field by means of three parameters, and we make use of the autoparallel trajectories, which in general differ from geodesics when torsion is present. We derive the specific approximate expression of the corresponding system of ordinary differential equations, which are then solved with methods of celestial mechanics. We calculate the secular variations of the longitudes of the node and of the pericenter of the satellite. The computed secular variations show how the corrections to the perihelion advance and to the orbital de Sitter effect depend on the torsion parameters. All computations are performed under the assumptions of weak field and slow motion. To test our predictions, we use the measurements of the Moon's geodetic precession from lunar laser ranging data, and the measurements of Mercury's perihelion advance from planetary radar ranging data. These measurements are then used to constrain suitable linear combinations of the torsion parameters.

  12. Primordial magnetic fields and dynamos from parity violated torsion

    NASA Astrophysics Data System (ADS)

    Garcia de Andrade, L. C.

    2012-05-01

    It is well known that torsion induced magnetic fields may seed galactic dynamos, but the price one pays for that is the conformal and gauge invariance breaks and a tiny photon mass. More recently I have shown [L.C. Garcia de Andrade, Phys. Lett. B 468 (2011) 28] that magnetic fields decay in a gauge invariant non-minimal coupling theory of torsion is slow down, which would allow for dynamo action to take place. In this Letter, by adding a parity violation term of the type Rɛ to the non-coupling term, a magnetic dynamo equation is obtained. From dynamo equation it is shown that torsion terms only appear in the dynamo equation when diffusion in the cosmic plasma is present. Torsion breaks the homogeneity of the magnetic field in the universe. Since Zeldovich anti-dynamo theorem assumes that the spacetime should be totally flat, torsion is responsible for violation of anti-dynamo theorem in 2D spatial dimensions. Contrary to previous results torsion induced primordial magnetic fields cannot seed galactic dynamos since from torsion and diffusion coefficient the decaying time of the magnetic field is 106yrs, which is much shorter than the galaxy age.

  13. Significance of torsion modes in bowed-string dynamics

    NASA Astrophysics Data System (ADS)

    Inacio, Octavio; Antunes, Jose; Henrique, Luis

    2002-11-01

    Several aspects of bowed-string dynamics are still inadequately clarified. The importance of torsion modes on the motion regimes is one such issue. Experiments involving torsion are difficult and most of the results available pertain to numerical simulations. The authors' approach differs from previous efforts in two main aspects: (1) the development of a computational method distinct from the wave-propagation approach pioneered by McIntyre, Schumacher, and Woodhouse and (2) an extensive and systematic analysis of the coupling between torsion and transverse motions is performed. The numerical simulations are based on a modal representation of the unconstrained string and a computational approach for friction that enables accurate representations of the stick-slip forces and of the string dynamics, in both time and space. Many relevant aspects of the bowed-string can be readily implemented, including string inharmonic behavior, finite bow-width, and torsion effects. Concerning the later aspect, a realistic range of the torsional to transverse wave-speed ratio is investigated, for several values of the bow velocity and normal force. Results suggest that torsion modes can effect both transient durations and steady state regimes, in particular when the above-mentioned ratio is <4. Gut strings should then be particularly prone to torsion effects.

  14. Pearls and pitfalls in diagnosis of ovarian torsion.

    PubMed

    Chang, Hannah C; Bhatt, Shweta; Dogra, Vikram S

    2008-01-01

    Ovarian torsion is defined as partial or complete rotation of the ovarian vascular pedicle and causes obstruction to venous outflow and arterial inflow. Ovarian torsion is usually associated with a cyst or tumor, which is typically benign; the most common is mature cystic teratoma. Ultrasonography (US) is the primary imaging modality for evaluation of ovarian torsion. US features of ovarian torsion include a unilateral enlarged ovary, uniform peripheral cystic structures, a coexistent mass within the affected ovary, free pelvic fluid, lack of arterial or venous flow, and a twisted vascular pedicle. The presence of flow at color Doppler imaging does not allow exclusion of torsion but instead suggests that the ovary may be viable, especially if flow is present centrally. Absence of flow in the twisted vascular pedicle may indicate that the ovary is not viable. The role of computed tomography (CT) has expanded, and it is increasingly used in evaluation of abdominal pain. Common CT features of ovarian torsion include an enlarged ovary, uterine deviation to the twisted side, smooth wall thickening of the twisted adnexal cystic mass, fallopian tube thickening, peripheral cystic structures, and ascites. Understanding the imaging appearance of ovarian torsion will lead to conservative, ovary-sparing treatment. PMID:18794312

  15. Torsion constraints from cosmological magnetic field and QCD domain walls

    NASA Astrophysics Data System (ADS)

    Garcia de Andrade, L. C.

    2014-10-01

    Earlier Kostelecky [Phys. Rev. D 69, 105009 (2004)] has investigated the role of gravitational sector in Riemann-Cartan (RC) spacetime with torsion, in Lorentz and CPT violating (LV) Standard Model extension (SME). In his paper use of quantum electrodynamic (QED) extension in RC spacetime is made. More recently L. C. Garcia de Andrade [Phys. Lett. B 468, 28 (2011)] obtained magnetic field galactic dynamo seeds in the bosonic sector with massless photons, which proved to decay faster than necessary [Phys. Lett. B 711, 143 (2012)] to be able to seed galactic dynamos. In this paper it is shown that by using the fermionic sector of Kostelecky-Lagrangian and torsion written as a chiral current, one obtains torsion and magnetic fields explicitly from a Heisenberg-Ivanenko form of Dirac equation whose solution allows us to express torsion in terms of LV coefficients and magnetic field in terms of fermionic matter fields. When minimal coupling between electromagnetic and torsion fields is used it is shown that the fermionic sector of QED with torsion leads to resonantly amplify magnetic fields which mimics an α2-dynamo mechanism. Fine-tuning of torsion is shown to result in the dynamo reversal, a phenomenon so important in solar physics and geophysics. Of course this is only an analogy since torsion is very weak in solar and geophysics contexts. An analogous expression for the α-effect of mean-field dynamos is also obtained where the α-effect is mimic by torsion. Similar resonant amplification mechanisms connected to early universe have been considered by Finelli and Gruppuso.

  16. Coupling and degenerating modes in longitudinal-torsional step horns.

    PubMed

    Harkness, Patrick; Lucas, Margaret; Cardoni, Andrea

    2012-12-01

    Longitudinal-torsional vibration is used and proposed for a variety of ultrasonic applications including motors, welding, and rock-cutting. To obtain this behavior in an ultrasonic step horn one can either, (i) couple the longitudinal and torsional modes of the horn by incorporating a ring of diagonal slits in the thick base section or, (ii) place helical flutes in the thin stem section to degenerate the longitudinal mode into a modified behavior with a longitudinal-torsional motion. This paper compares the efficacy of these two design approaches using both numerical and experimental techniques. PMID:22770885

  17. Spinning Particles in Scalar-Tensor Gravity with Torsion

    SciTech Connect

    Wang, C.-H.

    2008-10-10

    A new model of neutral spinning particles in scalar-tensor gravity with torsion is developed by using a Fermi coordinates associated with orthonormal frames attached to a timelike curve and Noether identities. We further analyze its equations of motion both in background Brans-Dicke torsion field and the constant pseudo-Riemannian curvature with a constant scalar field. It turns that the particle's spin vector is parallel transport along its wordline in the Brans-Dicke torsion field and de Sitter spacetime. However, the dynamics of the spinning particle cannot completely determined in anti-de Sitter spacetime and it requires a further investigation.

  18. Experimental investigation of cyclic thermomechanical deformation in torsion

    NASA Technical Reports Server (NTRS)

    Ellis, John R.; Castelli, Michael G.; Bakis, Charles E.

    1992-01-01

    An investigation of thermomechanical testing and deformation behavior of tubular specimens under torsional loading is described. Experimental issues concerning test accuracy and control specific to thermomechanical loadings under a torsional regime are discussed. A series of shear strain-controlled tests involving the nickel-base superalloy Hastelloy X were performed with various temperature excursions and compared to similar thermomechanical uniaxial tests. The concept and use of second invariants of the deviatoric stress and strain tensors as a means of comparing uniaxial and torsional specimens is also briefly presented and discussed in light of previous thermomechanical tests conducted under uniaxial conditions.

  19. Discussion on massive gravitons and propagating torsion in arbitrary dimensions

    SciTech Connect

    Hernaski, C. A.; Vargas-Paredes, A. A.; Helayeel-Neto, J. A.

    2009-12-15

    In this paper, we reassess a particular R{sup 2}-type gravity action in D dimensions, recently studied by Nakasone and Oda, now taking torsion effects into account. Considering that the vielbein and the spin connection carry independent propagating degrees of freedom, we conclude that ghosts and tachyons are absent only if torsion is nonpropagating, and we also conclude that there is no room for massive gravitons. To include these excitations, we understand how to enlarge Nakasone-Oda's model by means of explicit torsion terms in the action and we discuss the unitarity of the enlarged model for arbitrary dimensions.

  20. The Torsion of Box Beams with One Side Lacking

    NASA Technical Reports Server (NTRS)

    Cambilargiu, E

    1940-01-01

    The torsion of box beams of rectangular section, the edges of which are strengthened by flanges, and of which one side is lacking, is analyzed by the energy method. The torsional stresses are generally taken up by the bending of the two parallel walls, the rigidity of which is augmented by the third wall. The result was checked experimentally on duralumin and plywood boxes. The torsion recorded was 10 to 30 percent less than that given by the calculation, owing to self-stiffening.

  1. Four-fermion interaction from torsion as dark energy

    NASA Astrophysics Data System (ADS)

    Popławski, Nikodem J.

    2012-02-01

    The observed small, positive cosmological constant may originate from a four-fermion interaction generated by the spin-torsion coupling in the Einstein-Cartan-Sciama-Kibble gravity if the fermions are condensing. In particular, such a condensation occurs for quark fields during the quark-gluon/hadron phase transition in the early Universe. We study how the torsion-induced four-fermion interaction is affected by adding two terms to the Dirac Lagrangian density: the parity-violating pseudoscalar density dual to the curvature tensor and a spinor-bilinear scalar density which measures the nonminimal coupling of fermions to torsion.

  2. A Novel Endoscopic Method to Relieve Food Impaction Using an Inflatable Balloon.

    PubMed

    Anand, Rohit; Garg, Shashank; Dubin, Ethan; Dutta, Sudhir

    2015-01-01

    Food impaction in the esophagus is a relatively common medical emergency. Most of these food impactions are relieved spontaneously. But for complete esophageal food impactions or impactions not relieved spontaneously, traditional endoscopic methods like using a Roth net, polypectomy snare, or rat or alligator tooth forceps are used to gently manipulate the food material into the stomach. However, these methods may not work in certain circumstances. We present a case of proximal esophageal food impaction that was relieved using an inflatable balloon after the conventional methods proved unsuccessful. PMID:26266059

  3. Spin-torsion effects in the hyperfine structure of methanol

    SciTech Connect

    Coudert, L. H. Gutlé, C.; Huet, T. R.; Grabow, J.-U.; Levshakov, S. A.

    2015-07-28

    The magnetic hyperfine structure of the non-rigid methanol molecule is investigated experimentally and theoretically. 12 hyperfine patterns are recorded using molecular beam microwave spectrometers. These patterns, along with previously recorded ones, are analyzed in an attempt to evidence the effects of the magnetic spin-torsion coupling due to the large amplitude internal rotation of the methyl group [J. E. M. Heuvel and A. Dymanus, J. Mol. Spectrosc. 47, 363 (1973)]. The theoretical approach setup to analyze the observed data accounts for this spin-torsion in addition to the familiar magnetic spin-rotation and spin-spin interactions. The theoretical approach relies on symmetry considerations to build a hyperfine coupling Hamiltonian and spin-rotation-torsion wavefunctions compatible with the Pauli exclusion principle. Although all experimental hyperfine patterns are not fully resolved, the line position analysis yields values for several parameters including one describing the spin-torsion coupling.

  4. Structural and torsional vibration analysis of a dry screw compressor

    NASA Astrophysics Data System (ADS)

    Willie, J.; Sachs, R.

    2015-08-01

    This paper investigates torsional vibration and pulsating noise in a dry screw compressor. The compressor is designed at Gardner Denver (GD) and is oil free and use for mounting on highway trucks. They are driven using a Power Take-Off (PTO) transmission and gear box on a truck. Torque peak fluctuation and noise measurements are done and their sources are investigated and reported in this work. To accurately predict the torsional response (frequency and relative angular deflection and torque amplitude), the Holzer method is used. It is shown that the first torsional frequency is manifested as sidebands in the gear train meshing frequencies and this can lead to noise that is the result of amplitude modulation. Sensitivity analysis of the drive train identifies the weakest link in the drive train that limits the first torsional frequency to a low value. Finally, the significance of higher mode shapes on inter-lobe clearance distribution of the rotors is investigated.

  5. Torsional dynamics of steerable needles: modeling and fluoroscopic guidance.

    PubMed

    Swensen, John P; Lin, MingDe; Okamura, Allison M; Cowan, Noah J

    2014-11-01

    Needle insertions underlie a diversity of medical interventions. Steerable needles provide a means by which to enhance existing needle-based interventions and facilitate new ones. Tip-steerable needles follow a curved path and can be steered by twisting the needle base during insertion, but this twisting excites torsional dynamics that introduce a discrepancy between the base and tip twist angles. Here, we model the torsional dynamics of a flexible rod-such as a tip-steerable needle-during subsurface insertion and develop a new controller based on the model. The torsional model incorporates time-varying mode shapes to capture the changing boundary conditions inherent during insertion. Numerical simulations and physical experiments using two distinct setups-stereo camera feedback in semitransparent artificial tissue and feedback control with real-time X-ray imaging in optically opaque artificial tissue-demonstrate the need to account for torsional dynamics in control of the needle tip. PMID:24860026

  6. Randall-Sundrum scenario with bulk dilaton and torsion

    SciTech Connect

    Mukhopadhyaya, Biswarup; Sen, Somasri; SenGupta, Soumitra

    2009-06-15

    We consider a string-inspired torsion-dilaton-gravity action in a Randall-Sundrum braneworld scenario and show that, in an effective four-dimensional theory on the visible brane, the rank-2 antisymmetric Kalb-Ramond field (source of torsion) is exponentially suppressed. The result is similar to our earlier result in [B. Mukhopadhyaya, S. Sen, and S. SenGupta, Phys. Rev. Lett. 89, 121101 (2002); Phys. Rev. Lett. 89, 259902(E) (2002)], where no dilaton was present in the bulk. This offers an explanation of the apparent invisibility of torsion in our space-time. However, in this case the trilinear couplings {approx}TeV{sup -1} between the dilaton and torsion may lead to new signals in TeV-scale experiments, bearing the stamp of extra warped dimensions.

  7. Isolated adnexal torsion in a 20-week spontaneous twin pregnancy

    PubMed Central

    Kahramanoglu, Ilker; Eroglu, Vasfiye; Turan, Hasan; Kaval, Gizem; Sal, Veysel; Tokgozoglu, Nedim

    2016-01-01

    Background Adnexal torsion can be a life-threatning condition in pregnancy, while the risk of late diagnosis is increased, in second and third trimester in particular. Laparoscopy is an effective approach in diagnosis and treatment of adnexal torsion. However, entry to abdomen may be challenging in more advanced pregnancies. Case report Herein, we report a case of adnexal torsion during 20th week of twin pregnancy, which was detorsioned laparoscopically. The woman delivered healthy infants at her 36th week of pregnancy. Discussion Adnexal torsion as a cause of acute abdomen may be kept in mind in pregnants, even if there is no predisposing factor. Laparoscopy may be performed safely in 2nd trimester for acute abdomen. PMID:27129134

  8. Bilateral perinatal testicular torsion: successful salvage supports emergency surgery.

    PubMed

    Granger, Jeremy; Brownlee, Ewan M; Cundy, Thomas P; Goh, Day Way

    2016-01-01

    Perinatal testicular torsion (PTT) has poor rates of testicular salvage. Although rare, bilateral PTT carries the risk of anorchia. We present a case of a 2-day-old term infant with acute onset right-sided scrotal discolouration and tenderness. The infant was promptly taken to the operating theatre for emergency scrotal exploration. Bilateral extravaginal testicular torsion was identified, with the right testis appearing to have a more established ischaemic appearance compared to that on the left side. Intraoperative findings were representative of metachronous PTT with a short time period of only several hours separating the torsion events. Both testes were detorted and fixated in the scrotum. The infant made an uneventful recovery. Outpatient clinic review at 6 weeks and 6 months postoperatively confirmed no clinical evidence of testicular atrophy. Given the potential for contralateral torsion and the morbidity of anorchia, our experience supports the role for emergency scrotal exploration in suspected PTT. PMID:27307430

  9. Response characteristics of the human torsional vestibuloocular reflex

    NASA Technical Reports Server (NTRS)

    Peterka, Robert J.

    1992-01-01

    The characteristics of the response dynamics of the human torsional vestibuloocular reflex were studied during controlled rotations about an earth-horizontal axis. The results extended the frequency range to 2 Hz and identified the nonlinearity of the amplitude response.

  10. Structural diversity of supercoiled DNA

    NASA Astrophysics Data System (ADS)

    Irobalieva, Rossitza N.; Fogg, Jonathan M.; Catanese, Daniel J.; Sutthibutpong, Thana; Chen, Muyuan; Barker, Anna K.; Ludtke, Steven J.; Harris, Sarah A.; Schmid, Michael F.; Chiu, Wah; Zechiedrich, Lynn

    2015-10-01

    By regulating access to the genetic code, DNA supercoiling strongly affects DNA metabolism. Despite its importance, however, much about supercoiled DNA (positively supercoiled DNA, in particular) remains unknown. Here we use electron cryo-tomography together with biochemical analyses to investigate structures of individual purified DNA minicircle topoisomers with defined degrees of supercoiling. Our results reveal that each topoisomer, negative or positive, adopts a unique and surprisingly wide distribution of three-dimensional conformations. Moreover, we uncover striking differences in how the topoisomers handle torsional stress. As negative supercoiling increases, bases are increasingly exposed. Beyond a sharp supercoiling threshold, we also detect exposed bases in positively supercoiled DNA. Molecular dynamics simulations independently confirm the conformational heterogeneity and provide atomistic insight into the flexibility of supercoiled DNA. Our integrated approach reveals the three-dimensional structures of DNA that are essential for its function.

  11. Structural diversity of supercoiled DNA

    PubMed Central

    Irobalieva, Rossitza N.; Fogg, Jonathan M.; Catanese, Daniel J.; Sutthibutpong, Thana; Chen, Muyuan; Barker, Anna K.; Ludtke, Steven J.; Harris, Sarah A.; Schmid, Michael F.; Chiu, Wah; Zechiedrich, Lynn

    2015-01-01

    By regulating access to the genetic code, DNA supercoiling strongly affects DNA metabolism. Despite its importance, however, much about supercoiled DNA (positively supercoiled DNA, in particular) remains unknown. Here we use electron cryo-tomography together with biochemical analyses to investigate structures of individual purified DNA minicircle topoisomers with defined degrees of supercoiling. Our results reveal that each topoisomer, negative or positive, adopts a unique and surprisingly wide distribution of three-dimensional conformations. Moreover, we uncover striking differences in how the topoisomers handle torsional stress. As negative supercoiling increases, bases are increasingly exposed. Beyond a sharp supercoiling threshold, we also detect exposed bases in positively supercoiled DNA. Molecular dynamics simulations independently confirm the conformational heterogeneity and provide atomistic insight into the flexibility of supercoiled DNA. Our integrated approach reveals the three-dimensional structures of DNA that are essential for its function. PMID:26455586

  12. 21 CFR 310.532 - Drug products containing active ingredients offered over-the-counter (OTC) to relieve the...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... offered over-the-counter (OTC) to relieve the symptoms of benign prostatic hypertrophy. 310.532 Section... products containing active ingredients offered over-the-counter (OTC) to relieve the symptoms of benign... the ingredient sabal have been present in over-the-counter (OTC) drug products to relieve the...

  13. 21 CFR 310.532 - Drug products containing active ingredients offered over-the-counter (OTC) to relieve the...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... offered over-the-counter (OTC) to relieve the symptoms of benign prostatic hypertrophy. 310.532 Section... products containing active ingredients offered over-the-counter (OTC) to relieve the symptoms of benign... the ingredient sabal have been present in over-the-counter (OTC) drug products to relieve the...

  14. Misuse of Prescription Pain Relievers: The Buzz Takes Your Breath Away. Permanently.

    MedlinePlus

    ... street names: ac/dc, coties, demmies, dillies, hillbilly heroin, o.c., oxy, oxycotton, percs and vics to ... prescription pain relievers is like being hooked on heroin and the withdrawal isn't much different: bone ...

  15. Obstetrical Pain-relieving Drugs as Predictors of Infant Behavior Variability

    ERIC Educational Resources Information Center

    Aleksandrowicz, Malca K.; Aleksandrowicz, Dov R.

    1974-01-01

    A study of the relationship between pain-relieving drugs given to mothers during labor and delivery and neonatal behavior as assessed by the Brazelton Scales. Tested 44 infants on eight different days during their first month of life. (SDH)

  16. Ultrasonic Welding of Plastic Pipes Using Torsional Vibration

    NASA Astrophysics Data System (ADS)

    Masuzawa, Nobuyoshi; Hori, Kiichi; Ide, Masao

    1998-05-01

    In recent years, the application of ultrasonic welding to plastics has become common. In this paper a method for ultrasonic welding of plastic pipes using torsional vibrations is reported. In this method torsional vibrations are applied to the welding pipe from the circumferential direction with horns placed near the welding surface. Static pressure is independently applied from the vibrations to the welding surface. It was observed that acrylic resin pipes could be effectively welded by the proposed method.

  17. Changes in gravitational state cause changes in ocular torsion

    NASA Technical Reports Server (NTRS)

    Diamond, S. G.; Markham, C. H.

    1998-01-01

    Gravity-responsive eye torsion was studied simultaneously in both eyes during parabolic flight to determine the effects of weightlessness. Observed effects were that torsional position of eyes in the 1G states between parabolas was offset from the baseline positions obtained prior to the onset of parabolas, responses to hyper- and hypogravity were seen in most subjects, and responses were consistent within subjects but varied between subjects.

  18. Non-Abelian anomalies on a curved space with torsion

    SciTech Connect

    Cognola, G.; Giacconi, P.

    1989-05-15

    Using path-integral methods and /zeta/-function regularization a nonperturbative derivation of non-Abelian-covariant and consistent anomalies on a curved space with torsion is given. All terms depending on torsion, that one has in the expression of the consistent anomaly, can be eliminated by adding suitable counterterms to the Lagrangian density. In this way, the well-known result of Bardeen is recovered. The so-called ''covariant anomaly'' will be discussed too.

  19. Torsion of the Appendix Testis in a Neonate

    PubMed Central

    Krishnan, Arvind; Rich, Mark A.; Swana, Hubert S.

    2016-01-01

    Torsion of the appendix testis is a rare cause of scrotal swelling in the neonatal period. We present a case of torsion of the appendix testis in a one-day-old male. We discuss the physical examination and radiologic studies used to make the diagnosis. Nonoperative therapy was recommended and the patient has done well. Recognition of this condition in the neonatal period can prevent surgical intervention and its associated risks. PMID:27379193

  20. Cosmic Magnetic Fields from Torsion Modes and Massive Photon Inflation

    NASA Astrophysics Data System (ADS)

    Garcia de Andrade, L. C.

    2014-09-01

    Earlier Barrow & Tsagas (2008) showed that a slower decay of magnetic fields are present in open Friedmann universes, with traditional Maxwell equations. In their paper magnetic fields of the order of B˜10-33 G which are far below the value required to seed galactic dynamos were obtained. In this paper galactic dynamo seeds of the order of B˜10-23 G are obtained from massive electrodynamics in Einstein-Cartan-Proca (ECP) expanding universe of de Sitter type. Slow decay of magnetic fields in photon-torsion coupling in QED (Garcia de Andrade 2011b) have been recently shown by Garcia de Andrade (2012) also not be able to seed galactic dynamos. Torsion modes are constrained by the field equations. Space-time torsion is shown to be explicitly responsible for the slow decay of cosmic magnetic field. In the absence of massive photon torsion coupling the magnetic field decay is of the order B˜t-3/2, while when torsion is turn on B˜t-1.2. The pure massive-photon-torsion contribution amplifies the magnetic field by Btorsion˜t0.1 which characterizes an extremely slow magnetic dynamo action due to purely torsion gravitational effects. Recently, Barrow et al. (2012) have obtained superadiabatic amplification of B-fields in the Friedmann open cosmology which lies within 10-20 G and 10-12 G which falls very comfortable within limits to seed galactic dynamos. Other simple solutions where B-field decays as B˜a-1, relatively weak photon-torsion coupling approximation. These solutions are obtained for the de Sitter and Friedmann metrics.

  1. Analysis of the HVDC turbine generator torsional interactions

    SciTech Connect

    Padiyar, K.R. . Dept. of Electrical Communication Engineering); Kothari, A.G. )

    1989-01-01

    In the recent past it has been found that HVDC transmission systems and turbine-generator shaft torsional dynamics can interact in an unfavourable manner. This paper presents a detailed linearized state space model of AC/DC system to study this torsional interaction. The model developed is used to study the effect of various system parameters, such as, dc line loading, converter firing angle, the firing scheme employed. The results obtained are compared with those previously given.

  2. Torsional texturing of superconducting oxide composite articles

    DOEpatents

    Christopherson, Craig John; Riley, Jr., Gilbert N.; Scudiere, John

    2002-01-01

    A method of texturing a multifilamentary article having filaments comprising a desired oxide superconductor or its precursors by torsionally deforming the article is provided. The texturing is induced by applying a torsional strain which is at least about 0.3 and preferably at least about 0.6 at the surface of the article, but less than the strain which would cause failure of the composite. High performance multifilamentary superconducting composite articles having a plurality of low aspect ratio, twisted filaments with substantially uniform twist pitches in the range of about 1.00 inch to 0.01 inch (25 to 0.25 mm), each comprising a textured desired superconducting oxide material, may be obtained using this texturing method. If tighter twist pitches are desired, the article may be heat treated or annealed and the strain repeated as many times as necessary to obtain the desired twist pitch. It is preferred that the total strain applied per step should be sufficient to provide a twist pitch tighter than 5 times the diameter of the article, and twist pitches in the range of 1 to 5 times the diameter of the article are most preferred. The process may be used to make a high performance multifilamentary superconducting article, having a plurality of twisted filaments, wherein the degree of texturing varies substantially in proportion to the radial distance from the center of the article cross-section, and is substantially radially homogeneous at any given cross-section of the article. Round wires and other low aspect ratio multifilamentary articles are preferred forms. The invention is not dependent on the melting characteristics of the desired superconducting oxide. Desired oxide superconductors or precursors with micaceous or semi-micaceous structures are preferred. When used in connection with desired superconducting oxides which melt irreversibly, it provides multifilamentary articles that exhibit high DC performance characteristics and AC performance markedly

  3. Method of forming a stress relieved amorphous tetrahedrally-coordinated carbon film

    DOEpatents

    Friedmann, Thomas A.; Sullivan, John P.

    2000-01-01

    A stress-relieved amorphous-diamond film is formed by depositing an amorphous diamond film with specific atomic structure and bonding on to a substrate, and annealing the film at sufficiently high temperature to relieve the compressive stress in said film without significantly softening said film. The maximum annealing temperature is preferably on the order of 650.degree. C., a much lower value than is expected from the annealing behavior of other materials.

  4. Analysis of torsional oscillations using an artificial neural network

    SciTech Connect

    Hsu, Y.Y.; Jeng, L,H. )

    1992-12-01

    In this paper, a novel approach using an artificial neural network (ANN) is proposed for the analysis of torsional oscillations in a power system. In the developed artificial neural network, those system variables such as generator loadings and capacitor compensation ratio which have major impacts on the damping characteristics of torsional oscillatio modes are employed as the inputs. The outputs of the neural net provide the desired eigenvalues for torsional modes. Once the connection weights of the neural network have been learned using a set of training data derived off-line, the neural network can be applied to torsional analysis in real-time situations. To demonstrate the effectiveness of the proposed neural net, torsional analysis is performed on the IEEE First Benchmark Model. It is concluded from the test results that accurate assessment of the torsional mode eigenvalues can be achieved by the neural network in a very efficient manner. Thereofore, the proposed neural network approach can serve as a valuable tool to system operators in conducting SSR analysis in operational planning.

  5. A nationwide epidemiological study of testicular torsion in Korea.

    PubMed

    Lee, Sol Min; Huh, Jung-Sik; Baek, Minki; Yoo, Koo Han; Min, Gyeong Eun; Lee, Hyung-Lae; Lee, Dong-Gi

    2014-12-01

    Testicular torsion is a surgical emergency in the field of urology. Knowledge of the epidemiology and pathophysiology is significant to an urologist. However, the epidemiology of testicular torsion in Korea has not been studied. We performed a nationwide epidemiological study to improve knowledge of the epidemiology of testicular torsion. From 2006-2011, the Korean Urologic Association began the patient registry service. The annual number of patients with testicular torsion from 2006 to 2011 were 225, 250, 271, 277, 345, and 210, respectively. The overall incidence of testicular torsion in males was 1.1 per 100,000; However, the incidence in men less than 25 yr old was 2.9 per 100,000. Adolescents showed the highest incidence. Total testicular salvage rate was 75.7% in this survey. There was no geographic difference of testicular salvage rate. Minimizing the possibility of orchiectomy for testicular torsion is important to improve public awareness to expedite presentation and provider education to improve diagnosis and surgery. PMID:25469070

  6. An Axial-Torsional, Thermomechanical Fatigue Testing Technique

    NASA Technical Reports Server (NTRS)

    Kalluri, Sreeramesh; Bonacuse, Peter J.

    1995-01-01

    A technique for conducting strain-controlled, thermomechanical, axial-torsional fatigue tests on thin-walled tubular specimens was developed. Three waveforms of loading, namely, the axial strain waveform, the engineering shear strain waveform, and the temperature waveform were required in these tests. The phasing relationships between the mechanical strain waveforms and the temperature and axial strain waveforms were used to define a set of four axial-torsional, thermomechanical fatigue (AT-TMF) tests. Real-time test control (3 channels) and data acquisition (a minimum of 7 channels) were performed with a software program written in C language and executed on a personal computer. The AT-TMF testing technique was used to investigate the axial-torsional thermomechanical fatigue behavior of a cobalt-base superalloy, Haynes 188. The maximum and minimum temperatures selected for the AT-TMF tests were 760 and 316 C, respectively. Details of the testing system, calibration of the dynamic temperature profile of the thin-walled tubular specimen, thermal strain compensation technique, and test control and data acquisition schemes, are reported. The isothermal, axial, torsional, and in- and out-of-phase axial-torsional fatigue behaviors of Haynes 188 at 316 and 760 C were characterized in previous investigations. The cyclic deformation and fatigue behaviors of Haynes 188 in AT-TMF tests are compared to the previously reported isothermal axial-torsional behavior of this superalloy at the maximum and minimum temperatures.

  7. A new hybrid longitudinal-torsional magnetostrictive ultrasonic transducer

    NASA Astrophysics Data System (ADS)

    Karafi, Mohammad Reza; Hojjat, Yousef; Sassani, Farrokh

    2013-06-01

    In this paper, a novel hybrid longitudinal-torsional magnetostrictive ultrasonic transducer (HL-TMUT) is introduced. The transducer is composed of a magnetostrictive exponential horn and a stainless steel tail mass. In this transducer a spiral magnetic field made up of longitudinal and circumferential magnetic fields is applied to the magnetostrictive horn. As a result, the magnetostrictive horn oscillates simultaneously both longitudinally and torsionally in accordance with the Joule and Wiedemann effects. The magnetostrictive exponential horn is designed in such a manner that it has the same longitudinal and torsional resonant frequency. It is made up of ‘2V Permendur’, which has isotropic magnetic properties. The differential equations of the torsional and longitudinal vibration of the horn are derived, and a HL-TMUT is designed with a resonant frequency of 20 573 Hz. The natural frequency and mode shapes of the transducer are considered theoretically and numerically. The experimental results show that this transducer resonates torsionally and longitudinally with frequencies of 20 610 Hz and 20 830 Hz respectively. The maximum torsional displacement is 1.5 mrad m-1 and the maximum longitudinal displacement is 0.6 μm. These are promising features for industrial applications.

  8. DNA structure and function.

    PubMed

    Travers, Andrew; Muskhelishvili, Georgi

    2015-06-01

    The proposal of a double-helical structure for DNA over 60 years ago provided an eminently satisfying explanation for the heritability of genetic information. But why is DNA, and not RNA, now the dominant biological information store? We argue that, in addition to its coding function, the ability of DNA, unlike RNA, to adopt a B-DNA structure confers advantages both for information accessibility and for packaging. The information encoded by DNA is both digital - the precise base specifying, for example, amino acid sequences - and analogue. The latter determines the sequence-dependent physicochemical properties of DNA, for example, its stiffness and susceptibility to strand separation. Most importantly, DNA chirality enables the formation of supercoiling under torsional stress. We review recent evidence suggesting that DNA supercoiling, particularly that generated by DNA translocases, is a major driver of gene regulation and patterns of chromosomal gene organization, and in its guise as a promoter of DNA packaging enables DNA to act as an energy store to facilitate the passage of translocating enzymes such as RNA polymerase. PMID:25903461

  9. Control of Torsional Vibrations by Pendulum Masses

    NASA Technical Reports Server (NTRS)

    Stieglitz, Albert

    1942-01-01

    Various versions of pendulum masses have been developed abroad within the past few years by means of which resonant vibrations of rotating shafts can be eliminated at a given tuning. They are already successfully employed on radial engines in the form of pendulous counterweights. Compared with the commonly known torsional vibration dampers, the pendulum masses have the advantage of being structurally very simple, requiring no internal damping and being capable of completely eliminating certain vibrations. Unexplained, so far, remains the problem of behavior of pendulum masses in other critical zones to which they are not tuned, their dynamic behavior at some tuning other than in resonance, and their effect within a compound vibration system and at simultaneous application of several differently tuned pendulous masses. These problems are analyzed in the present report. The results constitute an enlargement of the scope of application of pendulum masses, especially for in-line engines. Among other things it is found that the natural frequency of a system can be raised by means of a correspondingly tuned pendulum mass. The formulas necessary for the design of any practical version are developed, and a pendulum mass having two different natural frequencies simultaneously is described.

  10. Dispersion and phase shifts of torsional waves in forward models

    NASA Astrophysics Data System (ADS)

    Cox, G. A.; Livermore, P. W.; Mound, J. E.

    2013-12-01

    Torsional Alfvén waves have been thought to exist in the Earth's core since their theoretical prediction by Braginsky in 1970. More recently, they have been inferred from observations of secular variation and length of day, and also observed in geodynamo simulations. These inferences from geophysical data have provided an important means of estimating core properties such as viscosity and internal magnetic field strength. We produce 1D forward models of torsional waves in the Earth's core, also known as torsional oscillations, and study their evolution in a cylinder, a full sphere and an equatorially symmetric spherical shell. The key features of torsional waves in our models are: geometric dispersion, phase shifts and internal reflections. In all three core geometries, we find that travelling torsional waves undergo significant geometric dispersion that increases with successive reflections from the boundaries such that an initial wave pulse becomes unidentifiable within three transits of the core. This dispersion partly arises due to low amplitude wakes trailing behind sharply defined pulses during propagation, a phenomenon that is linked to the failure of Huygens' principle in the geometric setting of torsional waves. We investigate the relationship between geometric dispersion and wavelength, concluding that long wavelength features are more dispersive than short wavelength features. This result is particularly important because torsional waves inferred from secular variation are relatively long wavelength, and are therefore likely to undergo significant dispersion within the Earth's core. Torsional waves in all three geometries are reflected at the equator of the core-mantle boundary with the same sign as the incident wave, but display more complicated behaviour at the rotation axis. In a cylindrical core, the analytic solutions to the torsional wave equation are known. We use these to derive an expression for the phase shift that torsional waves undergo upon

  11. Revealing the competition between peeled ssDNA, melting bubbles, and S-DNA during DNA overstretching by single-molecule calorimetry

    PubMed Central

    Zhang, Xinghua; Chen, Hu; Le, Shimin; Rouzina, Ioulia; Doyle, Patrick S.; Yan, Jie

    2013-01-01

    Double-stranded DNA (dsDNA) unconstrained by torsion undergoes an overstretching transition at about 65 pN, elongating the DNA to about 1.7-fold. Three possible structural transitions have been debated for the nature of DNA overstretching: (i) “peeling” apart of dsDNA to produce a peeled ssDNA strand under tension while the other strand coils, (ii) “inside-strand separation” of dsDNA to two parallel ssDNA strands that share tension (melting bubbles), and (iii) “B-to-S” transition to a novel dsDNA, termed S-DNA. Here we overstretched an end-opened DNA (with one open end to allow peeling) and an end-closed (i.e., both ends of the linear DNA are covalently closed to prohibit peeling) and torsion-unconstrained DNA. We report that all three structural transitions exist depending on experimental conditions. For the end-opened DNA, the peeling transition and the B-to-S transition were observed; for the end-closed DNA, the inside-strand separation and the B-to-S transition were observed. The peeling transition and the inside-strand separation are hysteretic and have an entropy change of approximately 17 cal/(K⋅mol), whereas the B-to-S transition is nonhysteretic and has an entropy change of approximately −2 cal/(K⋅mol). The force-extension curves of peeled ssDNA, melting bubbles, and S-DNA were characterized by experiments. Our results provide experimental evidence for the formation of DNA melting bubbles driven by high tension and prove the existence of nonmelted S-DNA. Our findings afford a full understanding of three possible force-driven structural transitions of torsion-unconstrained DNA and the resulting three overstretched DNA structures. PMID:23431154

  12. Elevated temperature axial and torsional fatigue behavior of Haynes 188

    NASA Technical Reports Server (NTRS)

    Bonacuse, Peter J.; Kalluri, Sreeramesh

    1992-01-01

    The results of high-temperature axial and torsional low-cycle fatigue experiments performed on Haynes 188, a wrought cobalt-base superalloy, are reported. Fatigue tests were performed at 760 C in air on thin-walled tubular specimens at various ranges under strain control. Data are also presented for coefficient of thermal expansion, elastic modulus, and shear modulus at various temperatures from room to 1000 C, and monotonic and cyclic stress-strain curves in tension and in shear at 760 C. The data set is used to evaluate several multiaxial fatigue life models (most were originally developed for room temperature multiaxial life prediction) including von Mises equivalent strain range (ASME boiler and pressure vessel code), Manson-Halford, Modified Multiaxiality Factor (proposed here), Modified Smith-Watson-Topper, and Fatemi-Socie-Kurath. At von Mises equivalent strain ranges (the torsional strain range divided by the square root of 3, taking the Poisson's ratio to be 0.5), torsionally strained specimens lasted, on average, factors of 2 to 3 times longer than axially strained specimens. The Modified Multiaxiality Factor approach shows promise as a useful method of estimating torsional fatigue life from axial fatigue data at high temperatures. Several difficulties arose with the specimen geometry and extensometry used in these experiments. Cracking at extensometer probe indentations was a problem at smaller strain ranges. Also, as the largest axial and torsional strain range fatigue tests neared completion, a small amount of specimen buckling was observed.

  13. Torsional Deformations in Subnanometer MoS Interconnecting Wires.

    PubMed

    Koh, Ai Leen; Wang, Shanshan; Ataca, Can; Grossman, Jeffrey C; Sinclair, Robert; Warner, Jamie H

    2016-02-10

    We use aberration-corrected transmission electron microscopy to track the real time atomic level torsional dynamics of subnanometer wires of MoS interconnecting monolayer regions of MoS2. An in situ heating holder is used inside the transmission electron microscope to raise the temperature of the sample to 400 °C to increase crystallization rates of the wires and reduce contamination effects. Frequent rotational twisting of the MoS wire is captured, demonstrating elastic torsional deformation of the MoS wires. We show that torsional rotations of the crystal structure of the MoS wires depend upon the specific atomic structure of the anchored sections of the suspended wire and the number of unit cells that make up the wire length. Elastic torsional flexibility of the MoS wires is revealed to help their self-adapting connectivity during the structural changes. Plastic torsional deformation is also seen for MoS wires that contain defects in their crystal structure, which produce small scale rotational disorder within the wires. Upon removal of the defects, the wire returns back to pristine form. These results provide detailed insights into how the atomic structure of the anchoring site significantly influences the nanowire configurations relative to the monolayered MoS2. PMID:26785319

  14. Simple torsion test for shear moduli determination of orthotropic composites

    NASA Technical Reports Server (NTRS)

    Sumsion, H. T.; Rajapakse, Y. D. S.

    1978-01-01

    By means of torsion tests performed on test specimens of the same material having a minimum of two different cross sections (flat sheet of different widths), the effective in-plane (G13) and out-of-plane (G23) shear moduli were determined for two composite materials of uniaxial and angleply fiber orientations. Test specimens were 16 plies (nominal 2 mm) thick, 100 mm in length, and in widths of 6.3, 9.5, 12.5, and 15.8 mm. Torsion tests were run under controlled deflection (constant angle of twist) using an electrohydraulic servocontrolled test system. In-plane and out-of-plane shear moduli were calculated from an equation derived in the theory of elasticity which relates applied torque, the torsional angle of twist, the specimen width/thickness ratio, and the ratio of the two shear moduli G13/G23. Results demonstrate that torsional shear moduli, G23 as well as G13, can be determined by simple torsion tests of flat specimens of rectangular cross section. Neither the uniaxial nor angleply composite material were transversely isotropic.

  15. Direct torsional actuation of microcantilevers using magnetic excitation

    SciTech Connect

    Gosvami, Nitya Nand; Nalam, Prathima C.; Tam, Qizhan; Carpick, Robert W.; Exarhos, Annemarie L.; Kikkawa, James M.

    2014-09-01

    Torsional mode dynamic force microscopy can be used for a wide range of studies including mapping lateral contact stiffness, torsional frequency or amplitude modulation imaging, and dynamic friction measurements of various materials. Piezo-actuation of the cantilever is commonly used, but it introduces spurious resonances, limiting the frequency range that can be sampled, and rendering the technique particularly difficult to apply in liquid medium where the cantilever oscillations are significantly damped. Here, we demonstrate a method that enables direct torsional actuation of cantilevers with high uniformity over wide frequency ranges by attaching a micrometer-scale magnetic bead on the back side of the cantilever. We show that when beads are magnetized along the width of the cantilever, efficient torsional actuation of the cantilevers can be achieved using a magnetic field produced from a solenoid placed underneath the sample. We demonstrate the capability of this technique by imaging atomic steps on graphite surfaces in tapping mode near the first torsional resonance of the cantilever in dodecane. The technique is also applied to map the variations in the lateral contact stiffness on the surface of graphite and polydiacetylene monolayers.

  16. Autoparallel vs. Geodesic Trajectories in a Model of Torsion Gravity

    NASA Astrophysics Data System (ADS)

    Acedo, Luis

    2015-11-01

    We consider a parametrized torsion gravity model for Riemann-Cartan geometry around a rotating axisymmetric massive body. In this model, the source of torsion is given by a circulating vector potential following the celestial parallels around the rotating object. Ours is a variant of the Mao, Tegmark, Guth and Cabi (MTGC model) in which the total angular momentum is proposed as a source of torsion. We study the motion of bodies around the rotating object in terms of autoparallel trajectories and determine the leading perturbations of the orbital elements by using standard celestial mechanics techniques. We find that this torsion model implies new gravitational physical consequences in the Solar system and, in particular, secular variations of the semi-major axis of the planetary orbits. Perturbations on the longitude of the ascending node and the perihelion of the planets are already under discussion in the astronomical community, and if confirmed as truly non-zero effects at a statistically significant level, we might be at the dawn of an era of torsion phenomenology in the Solar system.

  17. Numerical modeling of pendulum dampers in torsional systems

    SciTech Connect

    Johnston, P.R.; Shusto, L.M.

    1986-01-01

    Centrifugal pendulum-design dampers are utilized in torsional systems to reduce the vibration amplitude at certain objectionable torsional speeds. The damper is tuned by proper design of its mass, dimensions, and position on a carrier disk, which is rigidly attached to the torsional system. The effects of the pendulum damper on the response of the torsional system may be included by modifying the structural model to include a separate damper element representing each order of the pendulum damper. The stiffness and mass matrices for a damper element are dependent upon the order of vibration being dampened, the mass, and the geometry of the damper. A general form of the mass and stiffness equations for a simple centrifugal pendulum damper are derived from first principles using Lagrange's equations of motion. The analysis of torsional systems with pendulum dampers utilizing the mass and stiffness properties developed is included in the program SHAMS. SHAMS calculates the steady-state response of a system of springs and masses to harmonic loads using modal superposition. The response of a crankshaft system with and without the pendulum dampers are included as a case study.

  18. [Torsion of wandering spleen in a teenager: about a case].

    PubMed

    Dème, Hamidou; Akpo, Léra Géraud; Fall, Seynabou; Badji, Nfally; Ka, Ibrahima; Guèye, Mohamadou Lamine; Touré, Mouhamed Hamine; Niang, El Hadj

    2016-01-01

    Wandering or migrating spleen is a rare anomaly which is usually described in children. Complications, which include pedicle torsion, are common and can be life-threatening. We report the case of a 17 year-old patient with a long past medical history of epigastric pain suffering from wandering spleen with chronic torsion of the pedicle. The clinical picture was marked by spontaneously painful epigastric mass, evolved over the past 48 hours. Abdominal ultrasound objectified heterogeneous hypertrophied ectopic spleen in epigastric position and a subcapsular hematoma. Doppler showed a torsion of splenic pedicle which was untwisted 2 turns and a small blood stream on the splenic artery. Abdominal CT scan with contrast injection showed a lack of parenchymal enhancement of large epigastric ectopic spleen and a subcapsular hematoma. The diagnosis of wandering spleen with chronic torsion of the pedicle complicated by necrosis and subcapsular hematoma was confirmed. The patient underwent splenectomy. The postoperative course was uneventful. We here discuss the contribution of ultrasound and CT scan in the diagnosis of wandering spleen with chronic torsion of the pedicle. PMID:27583079

  19. Elevated temperature axial and torsional fatigue behavior of Haynes 188

    NASA Astrophysics Data System (ADS)

    Bonacuse, Peter J.; Kalluri, Sreeramesh

    1992-06-01

    The results of high-temperature axial and torsional low-cycle fatigue experiments performed on Haynes 188, a wrought cobalt-base superalloy, are reported. Fatigue tests were performed at 760 C in air on thin-walled tubular specimens at various ranges under strain control. Data are also presented for coefficient of thermal expansion, elastic modulus, and shear modulus at various temperatures from room to 1000 C, and monotonic and cyclic stress-strain curves in tension and in shear at 760 C. The data set is used to evaluate several multiaxial fatigue life models (most were originally developed for room temperature multiaxial life prediction) including von Mises equivalent strain range (ASME boiler and pressure vessel code), Manson-Halford, Modified Multiaxiality Factor (proposed here), Modified Smith-Watson-Topper, and Fatemi-Socie-Kurath. At von Mises equivalent strain ranges (the torsional strain range divided by the square root of 3, taking the Poisson's ratio to be 0.5), torsionally strained specimens lasted, on average, factors of 2 to 3 times longer than axially strained specimens. The Modified Multiaxiality Factor approach shows promise as a useful method of estimating torsional fatigue life from axial fatigue data at high temperatures. Several difficulties arose with the specimen geometry and extensometry used in these experiments. Cracking at extensometer probe indentations was a problem at smaller strain ranges. Also, as the largest axial and torsional strain range fatigue tests neared completion, a small amount of specimen buckling was observed.

  20. A Rare Cause of Placental Abruption: Uterine Torsion

    PubMed Central

    Güneş, Muhammed Siraç; Kiran, Gürkan; Gülşen, Mehmet Serdar

    2016-01-01

    Uterine torsion is defined as a rotation on its long axis and it is a dangerous, unexpected obstetric emergency. We report a case of uterine torsion at 32 weeks of gestation in a singleton pregnancy. A 37-year-old woman with multiple prior cesarean deliveries referred to emergency unit of our hospital at 32 weeks of gestation with severe abdominal pain and mild vaginal bleeding. Ultrasonography showed a single fetus in vertex position, with a normal amniotic fluid. Fetal biometer was appropriate for 32 weeks of gestation. Placental location was anterior with a subchorionic hypoechogenic small area which was suspected to be a sign of placental abruption. An emergency cesarean section was performed under general anesthesia. The 180° uterine torsion was diagnosed and it was not possible to perform detorsion of the gravid uterus by exteriorization by pfannenstiel incision. Posterior hysterotomy was performed and a male baby of 1830 grams weight was delivered. The newborn was transported to Neonatal Intensive Care Unit (NICU) of another hospital and discharged within two weeks. Patient recovered well and was discharged on second postoperation day. Uterine torsion is a very rare and life threatening situation. In unexpected cases posterior low transuerse hysterotomy is generally performed and it is suggested as a safe choice when detorsion was not accomplished. It is not easy to keep in mind the possibility of uterine torsion in cases of abdominal pain during pregnancy. Because it generally causes abruption, management of abruption is vitally important to prevent fetal mortality. PMID:26894131

  1. Usefulness of T2*-weighted MRI in the detection of adnexal torsion

    PubMed Central

    Kawai, Nobuyuki; Kanematsu, Masayuki; Kawaguchi, Shimpei; Kojima, Toshihisa; Furui, Tatsuro; Morishige, Ken-ichirou; Matsuo, Masayuki

    2016-01-01

    Background The usefulness of T2*-weighted (T2*W) imaging for the detection of adnexal torsion has yet to be determined. Purpose To assess the usefulness of T2*W imaging for detecting and differentiating adnexal torsion. Material and Methods Eight patients with eight ovaries with torsion and 44 patients with 72 ovaries without torsion were included in this study. All patients underwent 1.5-T magnetic resonance imaging (MRI) including T2*W images. The frequency and distribution of hypointensity on T2*W images were compared between ovaries with torsion and ovaries without torsion. Results Hypointensity on T2*W images was significantly more frequent in ovaries with torsion than in ovaries without torsion (75% vs. 36%; P < 0.05). Among patients with hypointensity on T2*W images, the frequency of diffuse hypointensity was significantly higher in ovaries with torsion than in ovaries without torsion (83% vs. 0%; P < 0.01); whereas the frequency of focal hypointensity was significantly lower in ovaries with torsion than in ovaries without torsion (17% vs. 100%; P < 0.01). Conclusion The presence and distribution of hypointensity on T2*W images may play a supplementary role in the detection of adnexal torsion. PMID:27478621

  2. [Theory analysis and clinical application of spirit-regulating and pain-relieving acupuncture method].

    PubMed

    Chen, Liang; Tang, Lewei; Du, Huaibin; Zheng, Hui; Liang, Fanrong

    2015-04-01

    The theoretical foundation and scientific connotation of spirit-regulating and pain-relieving acupuncture method as well as its clinical application for pain are discussed. During spirit regulation, attention should be paid on regulating heart and brain, while acupoints should be selected mainly from the Heart Meridian, Pericardium Meridian and Governor Vessel. It has significant efficacy for refractory pain in clinical treatment. Spirit-regulating and pain-relieving acupuncture method is development of acupuncture treating spirit, and it is an important method for pain in clinic. Improvement on sensitization of pain center and brain function is considered as one of the mechanisms in spirit-regulating and pain-relieving acupuncture method. PMID:26054155

  3. Torsion of Flanged Members with Cross Sections Restrained Against Warping

    NASA Technical Reports Server (NTRS)

    Hill, H N

    1943-01-01

    The longitudinal stresses and the stiffness of flange members - I-beams, channels, and Z-bars - were investigated when these members were subjected to torque with constraint against cross-sectional warping. Measured angles of rotation agreed with corresponding calculated values in which the torsion bending factor of the cross section was involved; the agreement was better for the I-beam and the Z-bar than for the channel. Longitudinal stresses measured at the mid-span were found to agree with the calculated values that involved unit warping as well as the torsion-bending factors: the channel showed the greatest discrepancy between measured and calculated values. When commonly given expressions for rotations and maximum longitudinal stresses in a twisted I-beam were applied to the channel and to the Z-bar, values were obtained that were in reasonably good agreement with values obtained by the method of torsion-bending constant and unit warping.

  4. Testicular torsion and the acute scrotum: current emergency management.

    PubMed

    Ta, Anthony; D'Arcy, Frank T; Hoag, Nathan; D'Arcy, John P; Lawrentschuk, Nathan

    2016-06-01

    The acute scrotum is a challenging condition for the treating emergency physician requiring consideration of a number of possible diagnoses including testicular torsion. Prompt recognition of torsion and exclusion of other causes may lead to organ salvage, avoiding the devastating functional and psychological issues of testicular loss and minimizing unnecessary exploratory surgeries. This review aims to familiarize the reader with the latest management strategies for the acute scrotum, discusses key points in diagnosis and management and evaluates the strengths and drawbacks of history and clinical examination from an emergency perspective. It outlines the types and mechanisms of testicular torsion, and examines the current and possible future roles of labwork and radiological imaging in diagnosis. Emergency departments should be wary of younger males presenting with the acute scrotum. PMID:26267075

  5. Complete axial torsion of pregnant uterus with leiomyoma

    PubMed Central

    Sachan, Rekha; Patel, M L; Sachan, Pushpalata; Arora, Anubha

    2014-01-01

    Uterine torsion is defined as a rotation of the uterus of more than 45° along its long axis. It is a rare complication during pregnancy; a common cause of torsion can be uterine myoma. Here we describe the case of a 27-year-old G2P1+0 woman at 15 weeks 3 day pregnancy, who presented to our outpatient department as a case of acute abdomen, in a state of shock. Clinical findings did not correlate with investigation. On lapratomy she was diagnosed as a case of complete axial torsion of pregnant uterus with fundal myoma with massive abruption. Early diagnosis and timely intervention would help in improving both maternal and fetal outcome. PMID:25193815

  6. Torsional vibration transmissibility characteristics of reinforced viscoelastic flexible pipes

    NASA Astrophysics Data System (ADS)

    Kennedy, I.; Tomlinson, G. R.

    1988-04-01

    The dynamic complex shear moduli of fibre and steel reinforced viscoelastic flexible pipes are determined by using a torsional non-resonance method. Material property master curves as a function of frequency and temperature are obtained by using reduced modulus methods. In situations where the loss factor data is difficult to measure directly it is shown that these data can be obtained from the modulus data by using a stepwise Hilbert transform technique. Predictions of the torsional vibration transmissibility of reinforced pipes, by using a simple theory in conjunction with the material properties, results in a close comparison with experimental measurements of the torsional vibration transmissibility characteristics of the pipes over a wide frequency range.

  7. The axial-torsional vibration of pretwisted beams

    NASA Astrophysics Data System (ADS)

    Liu, Kuang-Chen; Friend, James; Yeo, Leslie

    2009-03-01

    We investigate the coupled axial-torsional vibration of pretwisted beams. The equations of motion governing the extension, torsion, and cross-sectional warping of pretwisted beams are derived from Hamiltons principle, and the common assumptions used to simplify the equations are carefully examined through scaling analysis. Inconsistencies in previous works—such as the neglect of spatial and time derivatives of torsion in the Lagrangian functional—are remedied, giving rise to fourth-order terms in the equations of motion that are significant for higher harmonics. Furthermore, scaling analysis of the governing equations yields a set of objective criteria for checking the validity of the frequently misused assumption that the warping function under pretwist is locally identical to that of a prismatic beam; we show that this simplification is responsible for the common poor prediction of axial resonance frequencies for pretwisted beams.

  8. Fault diagnosis of planetary gearboxes via torsional vibration signal analysis

    NASA Astrophysics Data System (ADS)

    Feng, Zhipeng; Zuo, Ming J.

    2013-04-01

    Torsional vibration signals are theoretically free from the amplitude modulation effect caused by time variant vibration transfer paths due to the rotation of planet carrier and sun gear, and therefore their spectral structure are simpler than transverse vibration signals. Thus, it is potentially easy and effective to diagnose planetary gearbox faults via torsional vibration signal analysis. We give explicit equations to model torsional vibration signals, considering both distributed gear faults (like manufacturing or assembly errors) and local gear faults (like pitting, crack or breakage of one tooth), and derive the characteristics of both the traditional Fourier spectrum and the proposed demodulated spectra of amplitude envelope and instantaneous frequency. These derivations are not only effective to diagnose single gear fault of planetary gearboxes, but can also be generalized to detect and locate multiple gear faults. We validate experimentally the signal models, as well as the Fourier spectral analysis and demodulation analysis methods.

  9. Incorporation of another person's limb into body image relieves phantom limb pain: a case study.

    PubMed

    Weeks, Sharon R; Tsao, Jack W

    2010-12-01

    Phantom limb phenomena are well characterized, but the underlying mechanisms remain unclear. Here we report a patient who relieves his phantom sensations and pain, experienced as itching and cramping, through scratching or massaging his prosthesis or the leg of another person. This pain relief occurs only when phantom limb sensations are present. We hypothesize that symptom relief results from incorporation of the foreign limb into the patient's body image, mediated by the sensory mirror neuron system, relieving pain by restoring concordance between sensory systems. PMID:20425663

  10. Coupled composite rotor blades under bending and torsional loads

    NASA Astrophysics Data System (ADS)

    Chandra, Ramesh; Chopra, Inderjit

    This paper presents an analytical-cum-experimental study of the structural response of composite rotor blades with elastic couplings. Vlasov theory is expanded to analyze two-cell composite rotor blades made out of general composite laminates including the transverse shear deformation of the cross-section. In order to validate this analysis, two-cell graphite-epoxy composite blades with bending-torsion coupling were fabricated using matched-die molding technique. These blades were tested under tip bending and torsional loads, and their structural response in terms of bending slope and twist was measured with a laser optical system. Good correlation between theory and experiment is achieved.

  11. Cosmological evolution of a torsion-induced quintaxion

    SciTech Connect

    Mielke, Eckehard W.; Romero, Eric Sanchez

    2006-02-15

    In an affine prolongation of general relativity, the minimal coupling of Dirac fields to gravity naturally provides an axial current interaction. We demonstrate that the cancellation of the translational curvature, i.e. torsion, in the chiral anomaly induces a dynamical axion coupled with gravitational strength. Because of a geometrical identity, our torsion-induced pseudoscalar couples to the Einstein equations with an effective energy-momentum tensor which automatically satisfies the quintessence condition w<-1/3 for the equation of state parameter. In a toy model of an axion-dominated Universe, this leads to an anharmonic oscillatory evolution for which the deceleration parameter is within the range of current observations.

  12. Calibrations, torsion classes, and wrapped M-branes

    SciTech Connect

    Fayyazuddin, Ansar; Husain, Tasneem Zehra

    2006-05-15

    The present work has two goals. The first is to complete the classification of geometries in terms of torsion classes of M-branes wrapping cycles of a Calabi-Yau manifold. The second goal is to give insight into the physical meaning of the torsion class constraints. We accomplish both tasks by defining new energy minimizing calibrations in M-brane backgrounds. When fluxes are turned on, it is these calibrations that are relevant, rather than those which had previously been defined in the context of purely geometric backgrounds.

  13. Coated Fused Silica Fibers for Enhanced Sensitivity Torsion Pendulum

    NASA Technical Reports Server (NTRS)

    Numata, Kenji; Horowitz, Jordan; Camp, Jordan

    2007-01-01

    In order to investigate the fundamental thermal noise limit of a torsion pendulum using a fused silica fiber, we systematically measured and modeled the mechanical losses of thin fused silica fibers coated by electrically conductive thin metal films. Our results indicate that it is possible to achieve a thermal noise limit for coated silica lower by a factor between 3 and 9, depending on the silica diameter, compared to the best tungsten fibers available. This will allow a corresponding increase in sensitivity of torsion pendula used for weak force measurements, including the gravitational constant measurement and ground-based force noise testing for the Laser Interferometer Space Antenna (LISA) mission.

  14. On the Effective Control of Torsional Vibrations in Drilling Systems

    NASA Astrophysics Data System (ADS)

    Tucker, W. R.; Wang, C.

    1999-07-01

    This paper analyses a control mechanism designed to significantly ameliorate the sustained excitation of torsional relaxation oscillations (slip-stick) due to frictional torques generated by an active bit during drilling operations with an extended drill-string. The proposed mechanism of torsional rectification is compared with existing soft-torque devices in a series of mathematical models. Both analytic and numerical simulations indicate that many of the volatilities suffered by existing soft-torque feedback approaches used to combat slip-stick can be eliminated by the alternative proposed here.

  15. Research on wet etching at MEMS torsion mirror optical switch

    NASA Astrophysics Data System (ADS)

    Zhang, Yi; Wang, Jifeng; Luo, Yuan

    2002-10-01

    Etching is a very important technique at MEMS micromachining. There are two kinds of etching processing, the one is wet etching and the other is dry etching. In this paper, wet selective etching with KOH and tetramethyl ammonium hydroxide (TMAH) etchants is researched in order to make a torsion mirror optical switch. The experiments results show that TMAH with superphosphate is more suitable at MEMS torsion mirror optical switch micromachining than KOH, and it also has good compatibility with IC processing. Also our experiments results show some different with other reported research data. More work will be done to improve the yield rate of MEMS optical switch.

  16. New supersymmetric index of heterotic compactifications with torsion

    NASA Astrophysics Data System (ADS)

    Israël, Dan; Sarkis, Matthieu

    2015-12-01

    We compute the new supersymmetric index of a large class of N=2 heterotic compactifications with torsion, corresponding to principal two-torus bundles over warped K3 surfaces with H-flux. Starting from a UV description as a (0,2) gauged linear sigma-model with torsion, we use supersymmetric localization techniques to provide an explicit expression of the index as a sum over the Jeffrey-Kirwan residues of the one-loop determinant. We finally propose a geometrical formula that gives the new supersymmetric index in terms of bundle data, regardless of any particular choice of underlying two-dimensional theory.

  17. Noise limit of a torsion pendulum under optomechanical control

    NASA Astrophysics Data System (ADS)

    Tan, Yu-Jie; Hu, Zhong-Kun; Shao, Cheng-Gang

    2015-09-01

    In most torsion pendulum experiments, the force resolution is dominantly limited by thermal noise, which is proportional to the pendulum's intrinsic rigidity. Thus, increasing the rigidity directly, such as through increasing torsion fiber's diameter, will decrease the resolution. Here, we present a method to improve the rigidity of a pendulum indirectly through optomechanical control. In this method, for appropriate typical parameter values, the rigidity can be improved greatly. Meanwhile, the extra noise introduced, which our analysis focuses on, can be regulated within the thermal noise level, i.e., the force resolution may not decrease after optomechanical control. This can balance the conflict between large rigidity and high resolution.

  18. [Isolated torsion of the fallopian tube: about two cases].

    PubMed

    Bouguern, H; Bouchikhi, C; Chaara, H; Melhouf, M A; Banani, A

    2008-02-01

    Isolated torsion of the fallopian tube is extremely rare and difficult to diagnose, requires a coelioscopy, or a laparotomy in centers which do not have coelioscpie; often carried out too tardily, to allow the conservation of the horn. We report two observations of isolated torsion of the fallopian tube and we recall through the two clinical cases the diagnostic difficulties, the useful complementary examinations, the treatment and the causes of this pathology which must be systematically evoked in front of any acute abdominal syndrome in order to hope for an early surgical treatment and if possible conservative. PMID:18372548

  19. Elastic torsional buckling of thin-walled composite cylinders

    NASA Technical Reports Server (NTRS)

    Marlowe, D. E.; Sushinsky, G. F.; Dexter, H. B.

    1974-01-01

    The elastic torsional buckling strength has been determined experimentally for thin-walled cylinders fabricated with glass/epoxy, boron/epoxy, and graphite/epoxy composite materials and composite-reinforced aluminum and titanium. Cylinders have been tested with several unidirectional-ply orientations and several cross-ply layups. Specimens were designed with diameter-to-thickness ratios of approximately 150 and 300 and in two lengths of 10 in. and 20 in. The results of these tests were compared with the buckling strengths predicted by the torsional buckling analysis of Chao.

  20. N= 4 mechanics with diverse (4, 4, 0) multiplets: Explicit examples of hyper-Kähler with torsion, Clifford Kähler with torsion, and octonionic Kähler with torsion geometries

    SciTech Connect

    Fedoruk, Sergey Ivanov, Evgeny; Smilga, Andrei

    2014-05-15

    We present simple models of N= 4 supersymmetric mechanics with ordinary and mirror linear (4, 4, 0) multiplets that give a transparent description of Hyper-Kähler with Torsion (HKT), Clifford Kähler with Torsion (CKT), and Octonionic Kähler with Torsion (OKT) geometries. These models are treated in the N= 4 and N=2 superfield approaches, as well as in the component approach. Our study makes manifest that the CKT and OKT supersymmetric sigma models are distinguished from the more simple HKT models by the presence of extra holomorphic torsion terms in the supercharges.

  1. Nitrous oxide by itself is insufficient to relieve pain due to castration in piglet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surgical castration is performed on all male pigs in the United States. However, castration is painful and analgesics have been considered to relieve pain. Inhalant gases with analgesic properties allow for a fast induction, short-term and reversible effects, and are a needle-free option. Nitrous ox...

  2. A rare case of cannabis hyperemesis syndrome relieved by hot water bathing.

    PubMed

    Warner, Ben; Cairns, Stuart; Stone, Andy

    2014-02-01

    We present here a case of cannabinoid hyperemesis syndrome (CHS), which is an under-recognised disorder presenting in chronic abusers of cannabis typically as cyclical vomiting relieved by frequent hot baths. Increased awareness of CHS allows for earlier recognition by emergency departments, leading to prompter treatment and the prevention of future recurrence through cannabis cessation. PMID:24532755

  3. [Situation models in text comprehension: will emotionally relieving information be automatically activated?].

    PubMed

    Wentura, D; Nüsing, J

    1999-01-01

    It was tested whether the "situation model" framework can be applied to research on coping processes. Therefore, subjects (N = 80) were presented with short episodes (formulated in a self-referent manner) about everyday situations which potentially ended in a negative way (e.g., failures in achievement situations; losses etc.). The first half of each episode contained a critical sentence with emotionally relieving information. Given a negative ending, this information should be automatically activated due to its relieving effect. A two-factorial design was used. First, a phrase from the critical sentence was presented for recognition either after a negative ending, a positive ending, or before the ending. Second, with minor changes a control sentence (with an additionally distressing character) was constructed for each potentially relieving sentence. As hypothesized, an interaction emerged: Given a negative ending, the error rate was significantly lower for relieving information than for the control version, whereas there was no difference if the test phrase was presented before the end or after a positive end. PMID:10474322

  4. 21 CFR 868.5115 - Device to relieve acute upper airway obstruction.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Device to relieve acute upper airway obstruction. 868.5115 Section 868.5115 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5115 Device...

  5. 21 CFR 868.5115 - Device to relieve acute upper airway obstruction.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Device to relieve acute upper airway obstruction. 868.5115 Section 868.5115 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5115 Device...

  6. 21 CFR 868.5115 - Device to relieve acute upper airway obstruction.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Device to relieve acute upper airway obstruction. 868.5115 Section 868.5115 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5115 Device...

  7. 21 CFR 868.5115 - Device to relieve acute upper airway obstruction.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Device to relieve acute upper airway obstruction. 868.5115 Section 868.5115 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5115 Device...

  8. 21 CFR 868.5115 - Device to relieve acute upper airway obstruction.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Device to relieve acute upper airway obstruction. 868.5115 Section 868.5115 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5115 Device...

  9. Prescription Pain Reliever Abuse and Dependence among Adolescents: A Nationally Representative Study

    ERIC Educational Resources Information Center

    Wu, Li-Tzy; Ringwalt, Christopher L.; Mannelli, Paolo; Patkar, Ashwin A.

    2008-01-01

    The study investigates the prevalence, patterns, and correlates of adolescents' abuse, sub-threshold dependence, and dependence on prescription pain relievers (PPRs) in a nationally representative sample. Results show dependence on PPRs can take place without abuse and that sub-threshold dependence could have implications for major diagnostic…

  10. Korean Emotional Laborers' Job Stressors and Relievers: Focus on Work Conditions and Emotional Labor Properties

    PubMed Central

    Lee, Garam

    2015-01-01

    Background The present study aims to investigate job stressors and stress relievers for Korean emotional laborers, specifically focusing on the effects of work conditions and emotional labor properties. Emotional laborers are asked to hide or distort their real emotions in their interaction with clients. They are exposed to high levels of stress in the emotional labor process, which leads to serious mental health risks including burnout, depression, and even suicide impulse. Exploring job stressors and relieving factors would be the first step in seeking alternatives to protect emotional laborers from those mental health risks. Methods Using the third wave data of Korean Working Conditions Survey, logistic regression analysis was conducted for two purposes: to examine the relations of emotional labor and stress, and to find out job stressors and relievers for emotional laborers. Results The chances of stress arousal are 3.5 times higher for emotional laborers; emotional laborers experience double risk-burden for stress arousal. In addition to general job stressors, emotional laborers need to bear burdens related to emotional labor properties. The effect of social support at the workplace is not significant for stress relief, unlike common assumptions, whereas subjective satisfaction (wage satisfaction and work-life balance) is proven to have relieving effects on emotional laborers' job stress. Conclusion From the results, the importance of a balanced understanding of emotional labor for establishing effective policies for emotional laborer protection is stressed. PMID:26929847

  11. Quaternionic Torsion Geometry, Superconformal Symmetry and T-duality

    SciTech Connect

    Swann, Andrew

    2009-02-02

    HyperKaehler metrics with torsion (HKT metrics) are constructed via superconformal symmetry. It is shown how T-duality interpreted as a twist construction for circle actions provides a number of compact simply-connected examples. Further applications of the twist construction are discussed to obtain compact simply-connected HKT manifolds with few symmetries and to construct all HKT nilmanifolds.

  12. Nonlinear Fierz-Pauli theory from torsion and bigravity

    NASA Astrophysics Data System (ADS)

    Deffayet, C.; Randjbar-Daemi, S.

    2011-08-01

    The nonlinear aspects of a recently proposed model of massive spin-2 particles with propagating torsion are studied. We obtain a nonlinear equation which reduces at linear order to a generalized Fierz-Pauli equation in any background space-time with or without a vanishing torsion. We contrast those results with properties of a class of bigravity theories in an arbitrary background Einstein manifold. It is known that the nonperturbative spectrum of the bigravity model has 8 propagating physical degrees of freedom. This is identical to the physical propagating degrees of freedom of the massive spin-2 torsion model at the linearized order. The obtained nonlinear version of the Fierz-Pauli field equations, however, contains terms absent in the bigravity case which indicates that the curved space generalization of the unique flat space Fierz-Pauli equation is not unique. Moreover, in the torsion massive gravity model the Fierz-Pauli field appears as a derivative of fundamental fields. This, however, does not generate any unwanted pole once coupled to some external sources.

  13. Deligne-Beilinson cohomology and Abelian link invariants: Torsion case

    SciTech Connect

    Thuillier, F.

    2009-12-15

    For the Abelian Chern-Simons field theory, we consider the quantum functional integration over the Deligne-Beilinson cohomology classes and present an explicit path-integral nonperturbative computation of the Chern-Simons link invariants in SO(3){approx_equal}RP{sup 3}, a toy example of a 3-manifold with torsion.

  14. 34. VERTICAL AND TORSIONAL MOTION VIEWED FROM EAST TOWER, 7 ...

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

    34. VERTICAL AND TORSIONAL MOTION VIEWED FROM EAST TOWER, 7 NOVEMBER 1940, FROM 16MN FILM SHOT BY PROFESSOR F.B. FARQUHARSON, UNIVERSITY OF WASHINGTON. (LABORATORY STUDIES ON THE TACOMA NARROWS BRIDGE, AT UNIVERSITY OF WASHINGTON (SEATTLE: UNIVERSITY OF WASHINGTON, DEPARTMENT OF CIVIL ENGINEERING, 1941) - Tacoma Narrows Bridge, Spanning Narrows at State Route 16, Tacoma, Pierce County, WA

  15. Mechanical properties of orthodontic wires in tension, bending, and torsion.

    PubMed

    Drake, S R; Wayne, D M; Powers, J M; Asgar, K

    1982-09-01

    The mechanical properties of three sizes of stainless steel (SS), nickel-titanium (NT), and titanium-molybdenum (TM) orthodontic wires were studied in tension, bending, and torsion. The wires (0.016 inch, 0.017 by 0.025 inch, and 0.019 by 0.025 inch) were tested in the as-received condition. Tensile testing and stiffness testing machines along with a torsional instrument were used. Mean values and standard deviations of properties were computed. The data were analyzed statistically by analysis of variance using a factorial design. Means were ranked by a Tukey interval calculated at the 95 percent level of confidence. In tension, the stainless steel wires had the least maximum elastic strain or springback, whereas the titanium-molybdenum wires had the most. Higher values of springback indicate the capacity for an increased range of activation clinically. In bending and torsion, the stainless steel wires had the least stored energy at a fixed moment, whereas the nickel-titanium wires had the most. Spring rates in bending and torsion, however, were highest for stainless steel wires and lowest for nickel-titanium wires. A titanium-molybdenum teardrop closing loop delivered less than one half the force of a comparable stainless steel loop for similar activations. PMID:6961793

  16. Torsional Oscillations and Waves Projected on the Wall

    ERIC Educational Resources Information Center

    Bartlett, Albert A.

    2008-01-01

    The article "Torsional Oscillations with Lorentz Force" by Paul Gluck provides a glimpse into the major world of ancient physics demonstrations in the late 19th and first half of the 20th centuries. The apparatus that was described and similar pieces of apparatus are the basis for many memorable but long forgotten educational demonstrations. The…

  17. Testing gravity-induced collapse models with torsion pendulums

    NASA Astrophysics Data System (ADS)

    Helou, Bassam; Wipf, Christopher; Chen, Yanbei

    2016-03-01

    Wavefunction collapse models have been proposed to resolve the measurement problem in QM. Some, , such as Diosi-Penrose model, are motivated by gravity. We first present the theory of such models, highlighting new results, such as fixing the only free paramater in the model. We then propose torsion pendulums as a promising optomechanical platform to test such models.

  18. New Approaches to Data Acquisitions in a Torsion Pendulum Experiment

    ERIC Educational Resources Information Center

    Jiang, Daya; Xiao, Jinghua; Li, Haihong; Dai, Qionglin

    2007-01-01

    In this paper, two simple non-contact and cost-effective methods to acquire data in the student laboratory are applied to investigate the motion of a torsion pendulum. The first method is based on a Hall sensor, while the second makes use of an optical mouse.

  19. Solution of elastoplastic torsion problem by boundary integral method

    NASA Technical Reports Server (NTRS)

    Mendelson, A.

    1975-01-01

    The boundary integral method was applied to the elastoplastic analysis of the torsion of prismatic bars, and the results are compared with those obtained by the finite difference method. Although fewer unknowns were used, very good accuracy was obtained with the boundary integral method. Both simply and multiply connected bodies can be handled with equal ease.

  20. Cosmological solutions of a quadratic theory of gravity with torsion

    NASA Astrophysics Data System (ADS)

    Canale, Anna; de Ritis, Ruggiero; Tarantino, Ciro

    1984-01-01

    Following the general approach of Hehl, and Hayashi and Shirafuji, we give the gravity equations for the lagrangian L=(e/2L2)(F+1/2×F2) + LM. We have found the explicit Einstein-de Sitter solutions for a spinless dust. We have discussed in this case the singularity problem for the metric and for the torsion.

  1. Torsional waves operating in geodynamo and magnetoconvection simulations

    NASA Astrophysics Data System (ADS)

    Teed, Robert; Jones, Chris; Tobias, Steve

    2015-04-01

    Torsional waves are a principal feature of the dynamics of the fluid outer core where the Earth's magnetic field is generated. These oscillations are Alfvén waves operating about an equilibrium known as a Taylor state (Taylor, 1963) and they propagate in the cylindrical radial direction. The change in core angular momentum inferred from geomagnetic observations has a measurable impact on the length of the day, and the small decadal variations in the length-of-day signal confirm the existence of torsional oscillations (Holme & de Viron, 2013). Many questions remain unanswered about the exact nature of these waves and this presentation will attempt to address some of these. In order to gain insight we perform three-dimensional spherical dynamo and magnetoconvection simulations in parameter regimes where Earth-like magnetic fields are produced. Many of our simulations produce the desired torsional oscillations, identified by their movement at the correct Alfvén speed, and several show Earth-like core travel times of around 4 years. Our dynamo simulations (Teed et al., 2014) show torsional waves within the tangent cylinder region that also have the ability to pass through this theoretical cylinder. By calculating the driving terms for these waves we find that both the Reynolds force and ageostrophic convection acting through the Lorentz force can be important in driving torsional oscillations. Driven by a desire to reach smaller Ekman numbers and larger magnetic field strengths, which are computationally unattainable in dynamo simulations, we perform, in our follow up work, magnetoconvection simulations (Teed et al., 2015) by imposing a dipolar field on the core-mantle boundary. Under this configuration we find a transition, at low Ekman numbers, to regimes where excitation is found only at the tangent cylinder, is delivered by the Lorentz force and gives rise to a periodic Earth-like wave pattern. This pattern is approximately operating on a 4 to 5 year timescale

  2. Fallopian tube torsion in the pediatric age group: radiologic evaluation.

    PubMed

    Narayanan, Srikala; Bandarkar, Anjum; Bulas, Dorothy I

    2014-09-01

    Fallopian tube torsion is a rare but important cause of acute pelvic pain in young adolescent girls. It is a surgical emergency treated with either detorsion or salpingectomy. The imaging findings can be nonspecific and challenging. However, an accurate early diagnosis is essential for prompt surgical treatment. Our objective was to review whether imaging findings can be specific enough to suggest the diagnosis of tubal torsion prospectively in the appropriate clinical setting. An Institutional Review Board-approved retrospective review of our imaging database from 2005 to 2012 revealed 10 surgically proven cases of fallopian tube torsion. All cases had sonography performed; 5 cases had additional multidetector computed tomography. All 10 patients (9-17 years) presented with acute pelvic pain. Sonographic findings included dilated tubular structures in 6 of 10 cases: adjacent to a normal ipsilateral ovary in 5 of 6 and adjacent to a benign ovarian teratoma in 1. In 4 cases, no dilated tube was identified; 3 of 4 had a cystic mass separate from the ovaries, and 1 had the imaging appearance of a multicystic ovary. Computed tomographic findings in the 5 cases that underwent multidetector computed tomography included a dilated tubular structure in 3 of 5; 2 of 5 had a cystic adnexal mass identified. Although rare, tubal torsion should be considered in female adolescents with acute pelvic pain. Sonography should be the first imaging choice. When a tubular structure or a midline cystic mass associated with a normal ipsilateral ovary is noted, tubal torsion should be considered in the differential diagnosis. PMID:25154955

  3. Torsional ultrasound modality for hard nucleus phacoemulsification cataract extraction

    PubMed Central

    Zeng, M; Liu, X; Liu, Y; Xia, Y; Luo, L; Yuan, Z; Zeng, Y; Liu, Y

    2008-01-01

    Aim: To evaluate the efficacy and safety of phacoemulsification using torsional modality with different parameter settings for hard nucleus cataract extraction. Design: A prospective, randomised clinical study. Methods: A clinical practice study conducted at the Cataract Service, Zhongshan Ophthalmic Center, Sun-Yat-Sen University, and Guangzhou. One eye each from 198 consecutive patients with cataract density grade IV according to the Emery–Little system classification system, requiring phacoemulsification and intraocular lens implantation, was included. Eyes were randomly assigned to the Linear Torsional combined with Ultrasound power group (Linear Tor+US group, n = 66), 100% Fixed Torsional group (Fixed Tor group, n = 65) and conventional Ultrasound burst group (US group, n = 67). All surgeries were performed by a single experienced surgeon and outcomes evaluated by another surgeon masked to treatment. Intraoperative parameters were Ultrasound Time (UST), Cumulative Dissipated Energy (CDE) and surgical complications. Patients were examined on post-op days 1, 7 and 30. Postoperative outcomes were final best corrected visual acuity (BCVA), average central and incisional corneal thickness and central endothelial cell counts. Results: The mean UST was lower in the Fixed Tor group than in the US group and in the Lin US+Tor group (p⩽0.0001). The mean CDE was lower in the Lin Tor+US group and in the Fixed Tor group than in the US group (p⩽0.0001). Comparing with the two Tor group, the US group had a lower average BCVA on post-op 1, 7 (p⩽0.0001) and 30 (p>0.01), greater average central corneal and incisional thickness on days 1, 7 (p⩽0.0001) and 30 (p>0.01), and higher average corneal endothelial cell losses on day 7 and 30 days (p⩽0.0001). Conclusions: Torsional combined with ultrasound power or high fixed torsional amplitude can yield more effective hard nucleus phacoemulsification than conventional ultrasound modality. PMID:18567650

  4. Delamination behavior of quasi-isotropic graphite epoxy laminates subjected to tension and torsion loads

    NASA Technical Reports Server (NTRS)

    Hinkley, J. A.; Obrien, T. K.

    1992-01-01

    Sixteen and thirty-two ply quasi-isotropic laminates fabricated from AS4/3501-6 were subjected to pure tension, simultaneous tension and torsion, and torsion fatigue. Layups tested were (45 sub n/-45 sub n/O sub n/90 sub n) sub s, with n = 2 or 4. A torsion damage pattern consisting of a localized matrix crack and delaminations was characterized, and the measured torsional stiffnesses were compared with calculated values. It was found that a combination of tension and torsion led to failure at smaller loads than either type of deformation acting alone. Further work is required to determine the exact form of the failure criterion.

  5. A direct test of Listing's law--I. Human ocular torsion measured in static tertiary positions.

    PubMed

    Ferman, L; Collewijn, H; Van den Berg, A V

    1987-01-01

    The validity of Listing's law was reinvestigated by means of a direct test. Horizontal, vertical and torsional eye movements were measured simultaneously with a recently developed scleral induction coil. Either eye of 4 subjects was measured monocularly. Eye position were measured in Fick coordinates and ocular torsion values were compared to the theoretical ones predicted by Listing's law. During consecutive measurements in the primary position torsion values were close to zero although considerable fluctuations of torsion were seen. Torsion values in the secondary positions were also close to zero. In the tertiary positions torsion in the direction as predicted by Listing's law and increasing with eccentricity was recorded. In the temporal quadrants mean torsion was quantitatively in agreement with Listing's law; torsion values in the nasal quadrants however showed systematically larger values and this discrepancy increased with eccentricity to more than 50%. Statistical support for this finding however, was seen only in 4 out of 8 eyes. Symmetry could be obtained by shifting the chosen horizontal primary position (gaze parallel to the midplane) in the temporal direction; as a consequence all measured torsion values would exceed the ones specified by Listing's law. Torsion values varied idiosyncratically among subjects and among the left and right eyes of any one subject. It is concluded that Listing's law specifies ocular torsion only approximately: physiological eye movements show considerable stochastical as well as systematical deviations from this law. PMID:3660654

  6. Torsion Bounds from CP Violation α2-DYNAMO in Axion-Photon Cosmic Plasma

    NASA Astrophysics Data System (ADS)

    Garcia de Andrade, L. C.

    Years ago Mohanty and Sarkar [Phys. Lett. B 433, 424 (1998)] have placed bounds on torsion mass from K meson physics. In this paper, associating torsion to axions a la Campanelli et al. [Phys. Rev. D 72, 123001 (2005)], it is shown that it is possible to place limits on spacetime torsion by considering an efficient α2-dynamo CP violation term. Therefore instead of Kostelecky et al. [Phys. Rev. Lett. 100, 111102 (2008)] torsion bounds from Lorentz violation, here torsion bounds are obtained from CP violation through dynamo magnetic field amplification. It is also shown that oscillating photon-axion frequency peak is reduced to 10-7 Hz due to torsion mass (or Planck mass when torsion does not propagate) contribution to the photon-axion-torsion action. Though torsion does not couple to electromagnetic fields at classical level, it does at the quantum level. Recently, Garcia de Andrade [Phys. Lett. B 468, 28 (2011)] has shown that the photon sector of Lorentz violation (LV) Lagrangian leads to linear nonstandard Maxwell equations where the magnetic field decays slower giving rise to a seed for galactic dynamos. Torsion constraints of the order of K0≈10-42 GeV can be obtained which are more stringent than the value obtained by Kostelecky et al. A lower bound for the existence of galactic dynamos is obtained for torsion as K0≈10-37 GeV.

  7. Analytical and numerical models to predict the behavior of unbonded flexible risers under torsion

    NASA Astrophysics Data System (ADS)

    Ren, Shao-fei; Xue, Hong-xiang; Tang, Wen-yong

    2016-04-01

    This paper presents analytical and numerical models to predict the behavior of unbonded flexible risers under torsion. The analytical model takes local bending and torsion of tensile armor wires into consideration, and equilibrium equations of forces and displacements of layers are deduced. The numerical model includes lay angle, cross-sectional profiles of carcass, pressure armor layer and contact between layers. Abaqus/Explicit quasi-static simulation and mass scaling are adopted to avoid convergence problem and excessive computation time caused by geometric and contact nonlinearities. Results show that local bending and torsion of helical strips may have great influence on torsional stiffness, but stress related to bending and torsion is negligible; the presentation of anti-friction tapes may have great influence both on torsional stiffness and stress; hysteresis of torsion-twist relationship under cyclic loading is obtained by numerical model, which cannot be predicted by analytical model because of the ignorance of friction between layers.

  8. The Research on the Impact of Green Beans Sports Drinks on Relieving Fatigue in Sports Training.

    PubMed

    Qi, Li; Ying, Liu

    2015-01-01

    For researching the function of relieving fatigue of green beans sports drinks, this paper selected 60 mice as subjects. They were randomly divided into four groups (low dose group, middle dose group, high dose group and physiological saline group). Each time they were respectively feed 10g 20g/L, 40g/L, 80 g/L green beans sports drinks and 15ml/(kg.d) physiological saline. The experiment lasted for a month. We recorded weight of mice, swimming time and blood urea nitrogen indicators. The results show that green beans sports drinks can significantly prolong swimming time of mice (p <0.05). For serum urea the results show no effect. So green beans sports drinks have a certain function of relieving physical fatigue. PMID:26998181

  9. Automatic stress-relieving music recommendation system based on photoplethysmography-derived heart rate variability analysis.

    PubMed

    Shin, Il-Hyung; Cha, Jaepyeong; Cheon, Gyeong Woo; Lee, Choonghee; Lee, Seung Yup; Yoon, Hyung-Jin; Kim, Hee Chan

    2014-01-01

    This paper presents an automatic stress-relieving music recommendation system (ASMRS) for individual music listeners. The ASMRS uses a portable, wireless photoplethysmography module with a finger-type sensor, and a program that translates heartbeat signals from the sensor to the stress index. The sympathovagal balance index (SVI) was calculated from heart rate variability to assess the user's stress levels while listening to music. Twenty-two healthy volunteers participated in the experiment. The results have shown that the participants' SVI values are highly correlated with their prespecified music preferences. The sensitivity and specificity of the favorable music classification also improved as the number of music repetitions increased to 20 times. Based on the SVI values, the system automatically recommends favorable music lists to relieve stress for individuals. PMID:25571461

  10. An observation on combined use of chemotherapy and traditional Chinese medicine to relieve cancer pain.

    PubMed

    Lin, C; Lin, X; Yang, J

    1996-12-01

    We have treated 50 patients with stage III, VI malignant tumors confirmed by pathology. The patients were divided into two groups. One group was treated by combination of chemotherapy and traditional Chinese medicine (treatment group); the other only by chemotherapy (control group). The effect of cancer treatment was evaluated according to the criteria of WHO. The results showed that the effective rate was 80% in treatment group and 52% in control group. The pain relieving rate was 68% in treatment group and 40% in control group (P < 0.01). This fact demonstrates that the application of traditional Chinese medicine can invigorate blood circulation, eliminate blood stasis, soften hardness and dissolve the mass, nourish blood and increase vigor. This kind of application can not only enhance the effect of cancer treatment but also increase the cancer pain relieving rate. PMID:9389100

  11. Oxygen Relieves the CO2 and Acetate Dependency of Lactobacillus johnsonii NCC 533

    PubMed Central

    Hertzberger, Rosanne Y.; Pridmore, R. David; Gysler, Christof; Kleerebezem, Michiel; Teixeira de Mattos, M. Joost

    2013-01-01

    Oxygen relieves the CO2 and acetate dependency of Lactobacillus johnsonii NCC 533. The probiotic Lactobacillus johnsonii NCC 533 is relatively sensitive to oxidative stress; the presence of oxygen causes a lower biomass yield due to early growth stagnation. We show however that oxygen can also be beneficial to this organism as it relieves the requirement for acetate and CO2 during growth. Both on agar- and liquid-media, anaerobic growth of L. johnsonii NCC 533 requires CO2 supplementation of the gas phase. Switching off the CO2 supply induces growth arrest and cell death. The presence of molecular oxygen overcomes the CO2 dependency. Analogously, L. johnsonii NCC 533 strictly requires media with acetate to sustain anaerobic growth, although supplementation at a level that is 100-fold lower (120 microM) than the concentration in regular growth medium for lactobacilli already suffices for normal growth. Analogous to the CO2 requirement, oxygen supply relieves this acetate-dependency for growth. The L. johnsonii NCC 533 genome indicates that this organism lacks genes coding for pyruvate formate lyase (PFL) and pyruvate dehydrogenase (PDH), both CO2 and acetyl-CoA producing systems. Therefore, C1- and C2- compound production is predicted to largely depend on pyruvate oxidase activity (POX). This proposed role of POX in C2/C1-generation is corroborated by the observation that in a POX deficient mutant of L. johnsonii NCC 533, oxygen is not able to overcome acetate dependency nor does it relieve the CO2 dependency. PMID:23468944

  12. Well-Loved Music Robustly Relieves Pain: A Randomized, Controlled Trial

    PubMed Central

    Hsieh, Christine; Kong, Jian; Kirsch, Irving; Edwards, Robert R.; Jensen, Karin B.; Kaptchuk, Ted J.; Gollub, Randy L.

    2014-01-01

    Music has pain-relieving effects, but its mechanisms remain unclear. We sought to verify previously studied analgesic components and further elucidate the underpinnings of music analgesia. Using a well-characterized conditioning-enhanced placebo model, we examined whether boosting expectations would enhance or interfere with analgesia from strongly preferred music. A two-session experiment was performed with 48 healthy, pain experiment-naïve participants. In a first cohort, 36 were randomized into 3 treatment groups, including music enhanced with positive expectancy, non-musical sound enhanced with positive expectancy, and no expectancy enhancement. A separate replication cohort of 12 participants received only expectancy-enhanced music following the main experiment to verify the results of expectancy-manipulation on music. Primary outcome measures included the change in subjective pain ratings to calibrated experimental noxious heat stimuli, as well as changes in treatment expectations. Without conditioning, expectations were strongly in favor of music compared to non-musical sound. While measured expectations were enhanced by conditioning, this failed to affect either music or sound analgesia significantly. Strongly preferred music on its own was as pain relieving as conditioning-enhanced strongly preferred music, and more analgesic than enhanced sound. Our results demonstrate the pain-relieving power of personal music even over enhanced expectations. Trial Information Clinicaltrials.gov NCT01835275. PMID:25211164

  13. Flap-Lag-Torsion Stability in Forward Flight

    NASA Technical Reports Server (NTRS)

    Panda, B.; Chopra, I.

    1985-01-01

    An aeroelastic stability of three-degree flap-lag-torsion blade in forward flight is examined. Quasisteady aerodynamics with a dynamic inflow model is used. The nonlinear time dependent periodic blade response is calculated using an iterative procedure based on Floquet theory. The periodic perturbation equations are solved for stability using Floquet transition matrix theory as well as constant coefficient approximation in the fixed reference frame. Results are presented for both stiff-inplane and soft-inplane blade configurations. The effects of several parameters on blade stability are examined, including structural coupling, pitch-flap and pitch-lag coupling, torsion stiffness, steady inflow distribution, dynamic inflow, blade response solution and constant coefficient approximation.

  14. Bending and Torsion Load Alleviator With Automatic Reset

    NASA Technical Reports Server (NTRS)

    delaFuente, Horacio M. (Inventor); Eubanks, Michael C. (Inventor); Dao, Anthony X. (Inventor)

    1996-01-01

    A force transmitting load alleviator apparatus and method are provided for rotatably and pivotally driving a member to be protected against overload torsional and bending (moment) forces. The load alleviator includes at least one bias spring to resiliently bias cam followers and cam surfaces together and to maintain them in locked engagement unless a predetermined load is exceeded whereupon a center housing is pivotal or rotational with respect to a crown assembly. This pivotal and rotational movement results in frictional dissipation of the overload force by an energy dissipator. The energy dissipator can be provided to dissipate substantially more energy from the overload force than from the bias force that automatically resets the center housing and crown assembly to the normally fixed centered alignment. The torsional and bending (moment) overload levels can designed independently of each other.

  15. Nonlinear finite amplitude torsional vibrations of cantilevers in viscous fluids

    NASA Astrophysics Data System (ADS)

    Aureli, Matteo; Pagano, Christopher; Porfiri, Maurizio

    2012-06-01

    In this paper, we study torsional vibrations of cantilever beams undergoing moderately large oscillations within a quiescent viscous fluid. The structure is modeled as an Euler-Bernoulli beam, with thin rectangular cross section, under base excitation. The distributed hydrodynamic loading experienced by the vibrating structure is described through a complex-valued hydrodynamic function which incorporates added mass and fluid damping elicited by moderately large rotations. We conduct a parametric study on the two dimensional computational fluid dynamics of a pitching rigid lamina, representative of a generic beam cross section, to investigate the dependence of the hydrodynamic function on the governing flow parameters. As the frequency and amplitude of the oscillation increase, vortex shedding and convection phenomena increase, thus resulting into nonlinear hydrodynamic damping. We derive a handleable nonlinear correction to the classical hydrodynamic function developed for small amplitude torsional vibrations for use in a reduced order nonlinear modal model and we validate theoretical results against experimental findings.

  16. The frequencies of cantilever wings in beam and torsional vibrations

    NASA Technical Reports Server (NTRS)

    Burgess, C P

    1940-01-01

    Methods are described for calculating the period and frequency of vibration of cantilever wings and similar structures in which the weight and moment of inertia vary along the span. Both the beam and torsional frequencies may be calculated by these methods. The procedure is illustrated by examples. It is shown that a surprisingly close approximation to the beam frequency may be obtained by a very brief calculation in which the curvature of the wing in vibration is assumed to be constant. A somewhat longer computation permits taking account of the true curvature of the beam by a series of successive approximations which are shown to be strongly convergent. Analogous methods are applied to calculations of the torsional frequency. For the first approximation it is assumed that the angle of twist varies linearly alone the semispan. True variation of the twist is computed by successive approximations which are strongly convergent, as in the case of beam vibrations.

  17. Bending stresses due to torsion in cantilever box beams

    NASA Technical Reports Server (NTRS)

    Kuhn, Paul

    1935-01-01

    The paper beings with a brief discussion on the origin of the bending stresses in cantilever box beams under torsion. A critical survey of existing theory is followed by a summary of design formulas; this summary is based on the most complete solution published but omits all refinements considered unnecessary at the present state of development. Strain-gage tests made by NACA to obtained some experimental verification of the formulas are described next. Finally, the formulas are applied to a series of box beams previously static-tested by the U.S. Army Air Corps; the results show that the bending stresses due to torsion are responsible to a large extent for the free-edge type of failure frequently experienced in these tests.

  18. Development of a torsion balance for measuring charging noise

    NASA Astrophysics Data System (ADS)

    Campsie, P.; Hammond, G. D.; Hough, J.; Rowan, S.

    2012-06-01

    Noise due to surface charge on gravitational wave detector test masses could potentially become a limiting low frequency noise source in future detectors. It is therefore very important that the behavior of charging noise is experimentally verified so that accurate predictions of charging noise can be made. A torsion balance that is sensitive to small forces has been constructed at the University of Glasgow in order to measure charging noise. In this article the torsion balance apparatus being developed will be described in detail. There will also be a description of the calibration of the instrument and preliminary measurements that have been taken. These measurements show that it is possible to distinguish between the surface charge and polarisation charge on a silica sample. From this measurement it was possible to estimate the surface charge on the silica disc. The remainder of the article will discuss the improvements in sensitivity that have been made which will allow initial measurements of charging noise to begin.

  19. MAGNETOSEISMOLOGY: EIGENMODES OF TORSIONAL ALFVEN WAVES IN STRATIFIED SOLAR WAVEGUIDES

    SciTech Connect

    Verth, G.; Goossens, M.; Erdelyi, R. E-mail: Marcel.Goossens@wis.kuleuven.b

    2010-05-10

    There have recently been significant claims of Alfven wave observation in the solar chromosphere and corona. We investigate how the radial and longitudinal plasma structuring affects the observational properties of torsional Alfven waves in magnetic flux tubes for the purposes of solar magnetoseismology. The governing magnetohydrodynamic equations of these waves in axisymmetric flux tubes of arbitrary radial and axial plasma structuring are derived and we study their observable properties for various equilibria in both thin and finite-width magnetic flux tubes. For thin flux tubes, it is demonstrated that observation of the eigenmodes of torsional Alfven waves can provide temperature diagnostics of both the internal and surrounding plasma. In the finite-width flux tube regime, it is shown that these waves are the ideal magnetoseismological tool for probing radial plasma inhomogeneity in solar waveguides.

  20. The Torsion of Members Having Sections Common in Aircraft Construction

    NASA Technical Reports Server (NTRS)

    Trayer, George W; March, H W

    1930-01-01

    Within recent years a great variety of approximate torsion formulas and drafting-room processes have been advocated. In some of these, especially where mathematical considerations are involved, the results are extremely complex and are not generally intelligible to engineers. The principal object of this investigation was to determine by experiment and theoretical investigation how accurate the more common of these formulas are and on what assumptions they are founded and, if none of the proposed methods proved to be reasonable accurate in practice, to produce simple, practical formulas from reasonably correct assumptions, backed by experiment. A second object was to collect in readily accessible form the most useful of known results for the more common sections. Formulas for all the important solid sections that have yielded to mathematical treatment are listed. Then follows a discussion of the torsion of tubular rods with formulas both rigorous and approximate.

  1. Omental torsion in a captive polar bear (Ursus maritimus).

    PubMed

    Mendez-Angulo, Jose L; Funes, Francisco J; Trent, Ava M; Willette, Michelle; Woodhouse, Kerry; Renier, Anna C

    2014-03-01

    This is the first case report of an omental torsion in a polar bear (Ursus maritimus). A captive, 23-yr-old, 250-kg, intact female polar bear presented to the University of Minnesota Veterinary Medical Center with a 2-day history of lethargy, depression, and vomiting. Abdominal ultrasound identified large amounts of hyperechoic free peritoneal fluid. Ultrasound-guided abdominocentesis was performed and yielded thick serosanguinous fluid compatible with a hemoabdomen. An exploratory laparotomy revealed a large amount of malodorous, serosanguineous fluid and multiple necrotic blood clots associated with a torsion of the greater omentum and rupture of a branch of the omental artery. A partial omentectomy was performed to remove the necrotic tissue and the abdomen was copiously lavaged. The polar bear recovered successfully and is reported to be clinically well 6 mo later. This condition should be considered as a differential in bears with clinical signs of intestinal obstruction and hemoabdomen. PMID:24712179

  2. Interpreting Torsional Oscillator Measurements: Effect of Shear Modulus and Supersolidity

    NASA Astrophysics Data System (ADS)

    Reppy, John D.; Mi, Xiao; Justin, Alexander; Mueller, Erich J.

    2012-08-01

    The torsional oscillator is the chief instrument for investigating supersolidity in solid 4He. These oscillators can be sensitive to the elastic properties of the solid helium, which show anomalies over the same range of temperature in which the supersolid phenomenon appears. In this report we present a detailed study of the influence of the elastic properties of the solid on the periods of torsional oscillators for the various designs that have been commonly employed in supersolid measurements. We show how to design an oscillator which measures supersolidity, and how to design one which predominantly measures elasticity. We describe the use of multiple frequency TOs for the separation of the elastic and supersolid phenomena.

  3. State reversals of optically induced tilt and torsional eye movements

    NASA Technical Reports Server (NTRS)

    Finke, R. A.; Held, R.

    1978-01-01

    Alternations of the state of apparent self-motion during observation of a large visual display rotating about the line of sight are associated with alternations in the magnitude of induced tilt and torsional eye rotation. In one experiment, shifts in visually induced tilt during these state alternations are found to be in the opposite direction to corresponding shifts in induced ocular torsion. In a second experiment, the reversals of self-motion perception are shown to be an intravisual phenomenon, independent of competing inputs provided by the vestibular system. These results emphasize the importance of distinguishing between visual and vestibular processes in tilt perception and ocular rotation during human orientation to gravitational vertical.

  4. [TORSION OF FALLOPIAN TUBE LEIOMYOMA TREATED BY LAPAROSCOPY].

    PubMed

    Blagovest, Bechev; Magunska, Nadya; Kovachev, Emil; Ivanov, Stefan

    2016-01-01

    Leiomyomas of the Fallopian tubes are rare and their correct diagnosis is extremely difficult. Usually they are incidental findings seen at autopsy or unrelated surgical procedures: A 34-year-old woman presented with lower abdominal pain. Transvaginal ultrasound revealed a solid 7 cm extrauterine mass. Both ovaries are normal. Our preoperative diagnosis was torsion of the fallopian tube due intratubal leiomyoma. Laparoscopic surgery was performed and the leiomyoma was found to have originated from the isthmus of the right Fallopian tube. Laparoscopic myomectomy was performed with preservation of the ramus tubarius dextra. The histological examination concluded to a leiomyoma with ischemic changes. We report a case of torsion of a tubal leiomyoma, which was successfully managed laparoscopically. PMID:27509659

  5. Coupled Torsional and Bending Vibrations of Actively Controlled Drillstrings

    NASA Astrophysics Data System (ADS)

    YIGIT, A. S.; CHRISTOFOROU, A. P.

    2000-06-01

    The dynamics of actively controlled drillstrings is studied. The equations of motion are derived using a lumped parameter model in which the coupling between torsional and bending vibrations is considered. The model also includes the dynamics of the rotary drive system which contains the rotary table, the gearbox and an armature controlled DC motor. The interactions between the drillstring and the borehole which are considered, include the impacts of collars with the borehole wall as well as bit rotation-dependent weight and torque on bit (WOB and TOB). Simulation results obtained by numerically solving the equations of motion are in close qualitative agreement with field and laboratory observations regarding stick-slip oscillations. A linear quadratic regulator (LQR) controller is designed based on a linearized model and is shown to be effective in eliminating this type of oscillations. It is also shown that for some operational parameters the control action may excite large bending vibrations due to coupling with the torsional motion.

  6. Electric field in 3D gravity with torsion

    SciTech Connect

    Blagojevic, M.; Cvetkovic, B.

    2008-08-15

    It is shown that in static and spherically symmetric configurations of the system of Maxwell field coupled to 3D gravity with torsion, at least one of the Maxwell field components has to vanish. Restricting our attention to the electric sector of the theory, we find an interesting exact solution, corresponding to the azimuthal electric field. Its geometric structure is to a large extent influenced by the values of two different central charges, associated to the asymptotic AdS structure of spacetime.

  7. Nonlinear electrodynamics in 3D gravity with torsion

    SciTech Connect

    Blagojevic, M.; Cvetkovic, B.; Miskovic, O.

    2009-07-15

    We study exact solutions of nonlinear electrodynamics coupled to three-dimensional gravity with torsion. We show that in any static and spherically symmetric configuration, at least one component of the electromagnetic field has to vanish. In the electric sector of the theory, we construct an exact solution, characterized by the azimuthal electric field. When the electromagnetic action is modified by a topological mass term, we find two types of the self-dual solutions.

  8. A measurement of G with a cryogenic torsion pendulum.

    PubMed

    Newman, Riley; Bantel, Michael; Berg, Eric; Cross, William

    2014-10-13

    A measurement of Newton's gravitational constant G has been made with a cryogenic torsion pendulum operating below 4 K in a dynamic mode in which G is determined from the change in torsional period when a field source mass is moved between two orientations. The source mass was a pair of copper rings that produced an extremely uniform gravitational field gradient, whereas the pendulum was a thin fused silica plate, a combination that minimized the measurement's sensitivity to error in pendulum placement. The measurement was made using an as-drawn CuBe torsion fibre, a heat-treated CuBe fibre, and an as-drawn Al5056 fibre. The pendulum operated with a set of different large torsional amplitudes. The three fibres yielded high Q-values: 82 000, 120 000 and 164 000, minimizing experimental bias from fibre anelasticity. G-values found with the three fibres are, respectively: {6.67435(10),6.67408(15),6.67455(13)}×10(-11) m(3) kg(-1) s(-2), with corresponding uncertainties 14, 22 and 20 ppm. Relative to the CODATA2010 G-value, these are higher by 77, 37 and 107 ppm, respectively. The unweighted average of the three G-values, with the unweighted average of their uncertainties, is 6.67433(13)×10(-11) m(3) kg(-1) s(-2) (19 ppm). PMID:25202000

  9. Quantum simulations of nonlinear resonance and torsional dynamics

    NASA Astrophysics Data System (ADS)

    Collins, Michael A.; Schranz, Harold W.

    1994-02-01

    A simple model of the vibrational dynamics of ABBA type sequentially bonded tetra-atomic molecules is investigated by quantum mechanical methods. The model Hamiltonian excludes bond stretching and asymmetric bending but includes the kinematic coupling between the torsional motion and symmetric bond bending which results in nonlinear resonances. The effect of this coupling on energy levels and the timescale of intramolecular energy transfer is evaluated and discussed in terms of both resonant and nonresonant effects.

  10. 35. VERTICAL AND TORSIONAL MOTION FROM EAST TOWER SHOWING ANGULAR ...

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

    35. VERTICAL AND TORSIONAL MOTION FROM EAST TOWER SHOWING ANGULAR DISTORTION APPROACHING 45 DEGREES WITH LAMP POSTS APPEARING TO BE AT EIGHT ANGLES, 7 NOVEMBER 1940, FROM 16MN FILM SHOT BY PROFESSOR F.B. FARQUHARSON, UNIVERSITY OF WASHINGTON. (LABORATORY STUDIES ON THE TACOMA NARROWS BRIDGE, AT UNIVERSITY OF WASHINGTON SEATTLE: UNIVERSITY OF WASHINGTON, DEPARTMENT OF CIVIL ENGINEERING, 1941) - Tacoma Narrows Bridge, Spanning Narrows at State Route 16, Tacoma, Pierce County, WA

  11. Calibration of combined bending-torsion fatigue reliability data reduction

    NASA Technical Reports Server (NTRS)

    Kececioglu, D.; Mcconnell, J. B.

    1969-01-01

    The combined bending-torsion fatigue reliability research machines are described. Three such machines are presently in operation. The calibration of these machines is presented in depth. Fatigue data generated with these machines for SAE 4340 steel grooved specimens subjected to reversed bending and steady torque loading are given. The data reduction procedure is presented. Finally, some comments are made about notch sensitivity and stress concentration as applied to combined fatigue.

  12. The initial torsional stiffness of shells with interior webs

    NASA Technical Reports Server (NTRS)

    Kuhn, Paul

    1935-01-01

    A method of calculating the stresses and torsional stiffness of thin shells with interior webs is summarized. Comparisons between experimental and calculated results are given for 3 duralumin beams, 5 stainless steel beams and 2 duralumin wings. It is concluded that if the theoretical stiffness is multiplied by a correction factor of 0.9, experimental values may be expected to check calculated values within about 10 percent.

  13. Torsion of the Abomasum in a One Month Old Calf

    PubMed Central

    Frazee, L. S.

    1984-01-01

    The clinical and clinicopathological findings of a one month old Holstein heifer calf presented with severe abdominal distention are reported. Preoperative evaluation and therapy were initiated and followed by an exploratory laparotomy (paracostal right flank) which revealed a 360° counterclockwise torsion (viewed from the rear) of the abomasum. Severe vascular compromise of the abomasum precluded salvage of the animal. Following euthanasia and postmortem evaluation, the calf was found to have irreversible changes within the abomasum. PMID:17422429

  14. Genetic and clinical features of primary torsion dystonia

    PubMed Central

    Ozelius, Laurie J.; Bressman, Susan B.

    2011-01-01

    Primary torsion dystonia (PTD) is defined as a syndrome in which dystonia is the only clinical sign (except for tremor), and there is no evidence of neuronal degeneration or an acquired cause by history or routine laboratory assessment. Seven different loci have been recognized for PTD but only two of the genes have been identified. In this review we will described the phenotypes associated with these loci and discuss the responsible gene. PMID:21168499

  15. Observation of 1990 solar eclipse by a torsion pendulum

    SciTech Connect

    Luo Jun; Li Jianguo; Zhang Xuerong ); Liakhovets, V. ); Lomonosov, M.; Ragyn, A. )

    1991-10-15

    During the solar eclipse of 22 July 1990 in the city of Bielomorsk of the U.S.S.R., we repeated the torsion pendulum experiment of Saxl and Allen, who reported an anomalous period increase during the solar eclipse of 7 March 1970. The relative change in the pendulum's period associated with the eclipse was found to be less than 5.2{times}10{sup {minus}5} (90% confidence).

  16. Tops and Writhing DNA

    NASA Astrophysics Data System (ADS)

    Samuel, Joseph; Sinha, Supurna

    2011-04-01

    The torsional elasticity of semiflexible polymers like DNA is of biological significance. A mathematical treatment of this problem was begun by Fuller using the relation between link, twist and writhe, but progress has been hindered by the non-local nature of the writhe. This stands in the way of an analytic statistical mechanical treatment, which takes into account thermal fluctuations, in computing the partition function. In this paper we use the well known analogy with the dynamics of tops to show that when subjected to stretch and twist, the polymer configurations which dominate the partition function admit a local writhe formulation in the spirit of Fuller and thus provide an underlying justification for the use of Fuller's "local writhe expression" which leads to considerable mathematical simplification in solving theoretical models of DNA and elucidating their predictions. Our result facilitates comparison of the theoretical models with single molecule micromanipulation experiments and computer simulations.

  17. Optical diagnosis of testicular torsion: feasibility and methodology

    NASA Astrophysics Data System (ADS)

    Shadgan, Babak; Macnab, Andrew; Stothers, Lynn; Kajbafzadeh, A. M.

    2014-03-01

    Background: Torsion of the testis compromises blood flow through the spermatic cord; testicular ischemia results which if not diagnosed promptly and corrected surgically irrevocably damages the testis. Current diagnostic modalities aimed at rationalizing surgical exploration by demonstrating interruption of spermatic cord blood flow or testicular ischemia have limited applicability. Near infrared spectroscopy (NIRS) offers a non-invasive optical method for detection of ischemia; continuous wave and frequency domain devices have been used experimentally; no device customized for clinical use has been designed. Methods: A miniature spatially resolved NIRS device with light emitting diode light source was applied over the right and left spermatic cord and the difference in oxygen saturation between the two sides measured. Results: In a 14-month old boy with a history of unilateral testicular pain color Doppler ultrasonography was equivocal but the NIRS-derived tissue oxygen saturation index (TSI) was significantly reduced on the left side. Confirmation of torsion of the left testicle was made surgically. Conclusions: Spatially resolved NIRS monitoring of spermatic cord oxygen saturation is feasible in children, adding to prior studies of testicular oxygen saturation in adults. Customized device design and further clinical trials would enhance the applicability of NIRS as a diagnostic entity for torsion.

  18. Torsional stiffness degradation and aerostatic divergence of suspension bridge decks

    NASA Astrophysics Data System (ADS)

    Zhang, Z. T.; Ge, Y. J.; Yang, Y. X.

    2013-07-01

    The mechanism of aerostatic torsional divergence (ATD) of long-span suspension bridges is investigated. A theoretical analysis on the basis of a generalized model is presented, showing that the vertical motion of a bridge deck is crucial to the torsional stiffness of the whole suspended system, and that the vertical motion of either cable with a magnitude beyond a certain threshold could result in a sudden degradation of the torsional stiffness of the system. This vertical motion-induced degradation of stiffness is recognized as the main reason for the ATD. Long-span suspension bridges are susceptible to such a type of divergence, especially when they are immersed in turbulent wind fields. The divergences that occur in turbulent wind fields differ significantly from those in smooth wind fields, and the difference is well explained by the generalized model that the loosening of any one cable could result in the vanishing of the part of stiffness provided by the whole cable system. The mechanism revealed in this paper leads to a definition of the critical wind speed of the ATD in a turbulent flow; that is, the one resulting in a vertical motion so large as to loosen either cable to a stressless state. Numerical results from the nonlinear finite-element (FE) analysis of the Xihoumen suspension bridge, in conjunction with observations from wind tunnel tests on an aero-elastic full bridge model, are in support of the viewpoint presented in this study.

  19. Pound-Rebka experiment and torsion in the Schwarzschild spacetime

    SciTech Connect

    Maluf, J. W.; Ulhoa, S. C.; Faria, F. F.

    2009-08-15

    We develop some ideas discussed by E. Schucking [arXiv:0803.4128] concerning the geometry of the gravitational field. First, we address the concept according to which the gravitational acceleration is a manifestation of the space-time torsion, not of the curvature tensor. It is possible to show that there are situations in which the geodesic acceleration of a particle may acquire arbitrary values, whereas the curvature tensor approaches zero. We conclude that the space-time curvature does not affect the geodesic acceleration. Then we consider the Pound-Rebka experiment, which relates the time interval {delta}{tau}{sub 1} of two light signals emitted at a position r{sub 1}, to the time interval {delta}{tau}{sub 2} of the signals received at a position r{sub 2}, in a Schwarzschild type gravitational field. The experiment is determined by four space-time events. The infinitesimal vectors formed by these events do not form a parallelogram in the (t,r) plane. The failure in the closure of the parallelogram implies that the space-time has torsion. We find the explicit form of the torsion tensor that explains the nonclosure of the parallelogram.

  20. Friction and shear fracture of an adhesive contact under torsion

    NASA Astrophysics Data System (ADS)

    Chateauminois, Antoine; Fretigny, Christian; Olanier, Ludovic

    2010-02-01

    The shear failure or stiction of an adhesive contact between a poly(dimethylsiloxane) (PDMS) rubber and a glass lens has been investigated using a torsional contact configuration. As compared to linear sliding, torsion presents the advantage of inducing a shear failure under a pure mode III condition, while preserving the cylindrical symmetry of the contact. The surface of the transparent PDMS substrate was marked using a network of dots in order to monitor continuously the in-plane surface displacements during the stiction process. Using a previously developed inversion procedure (A. Chateauminois and C. Fretigny, Eur. Phys. J. E 27, 221 (2008)), the corresponding surface shear stress distributions were obtained from the displacement fields. Stiction was found to involve the progressive shrinkage of a central adhesive zone surrounded by an annular microslip region. Adhesion effects were especially evidenced from a stress overshoot at the boundary of the adhesive zone. The experimental data were analysis using an extension to torsional contact of the Maugis-Dugdale approach’s to adhesive contacts which takes into account frictional effects. This model allowed to extract an effective adhesion energy in the presence of friction, which dependence on kinetics effect is briefly discussed.

  1. Intravitreal Phacoemulsification Using Torsional Handpiece for Retained Lens Fragments

    PubMed Central

    Kumar, Vinod; Takkar, Brijesh

    2016-01-01

    Purpose: To evaluate the results of intravitreal phacoemulsification with torsional hand piece in eyes with posteriorly dislocated lens fragments. Methods: In this prospective, interventional case series, 15 eyes with retained lens fragments following phacoemulsification were included. All patients underwent standard three-port pars plana vitrectomy and intravitreal phacoemulsification using sleeveless, torsional hand piece (OZiL™, Alcon's Infiniti Vision System). Patients were followed up for a minimum of six months to evaluate the visual outcomes and complications. Results: The preoperative best-corrected visual acuity (BCVA) ranged from light perception to 0.3. No complications such as thermal burns of the scleral wound, retinal damage due to flying lens fragments, or difficult lens aspiration occurred during intravitreal phacoemulsification. Mean post-operative BCVA at the final follow-up was 0.5. Two eyes developed cystoid macular edema, which was managed medically. No retinal detachment was noted. Conclusion: Intravitreal phacoemulsification using torsional hand piece is a safe and effective alternative to conventional longitudinal phacofragmentation.

  2. Closed-loop adaptive control for torsional micromirrors

    NASA Astrophysics Data System (ADS)

    Liao, Ke-Min; Wang, Yi-Chih; Yeh, Chih-Hsien; Chen, Rongshun

    2004-01-01

    An adaptive control scheme to achieve accurate positioning and trajectory tracking of torsional micromirror is presented in this study. The torsional micromirror is fabricated by using surface micromachining processes, in which phosphorusdoped polysilicon is employed as the structure layer as well as the bottom electrode. Generally, every fabrication step contributes to imperfections in micromirror. The proposed adaptive self-tuning controller has advantages of on-line compensating parameter variations or model uncertainty of the torsional micromirror, resulting from fabrication imperfections that produce asymmetric structures, misalignment of actuation mechanism, and deviations of the center of mass from the geometric center. In our design, the amount of detection of differential capacitance between the left and right electrodes at the femtofarad (fF) level is utilized as feedback signals. Simulation results show that the designed controller has better transient response compared to the PID control scheme. The micromirror can follow the reference trajectory (5 kHz) with acceptable error in several microseconds, thus the convergence of the controller is confirmed. Furthermore, the unknown model parameters can be identified correctly while the so-called persistent excitation condition is satisfied.

  3. Quick phases control ocular torsion during smooth pursuit.

    PubMed

    Hess, Bernhard J M; Thomassen, Jakob S

    2011-11-01

    One of the open questions in oculomotor control of visually guided eye movements is whether it is possible to smoothly track a target along a curvilinear path across the visual field without changing the torsional stance of the eye. We show in an experimental study of three-dimensional eye movements in subhuman primates (Macaca mulatta) that although the pursuit system is able to smoothly change the orbital orientation of the eye's rotation axis, the smooth ocular motion was interrupted every few hundred milliseconds by a small quick phase with amplitude <1.5° while the animal tracked a target along a circle or ellipse. Specifically, during circular pursuit of targets moving at different angular eccentricities (5°, 10°, and 15°) relative to straight ahead at spatial frequencies of 0.067 and 0.1 Hz, the torsional amplitude of the intervening quick phases was typically around 1° or smaller and changed direction for clockwise vs. counterclockwise tracking. Reverse computations of the eye rotation based on the recorded angular eye velocity showed that the quick phases facilitate the overall control of ocular orientation in the roll plane, thereby minimizing torsional disturbances of the visual field. On the basis of a detailed kinematic analysis, we suggest that quick phases during curvilinear smooth tracking serve to minimize deviations from Donders' law, which are inevitable due to the spherical configuration space of smooth eye movements. PMID:21715669

  4. On discrete symmetries and torsion homology in F-theory

    NASA Astrophysics Data System (ADS)

    Mayrhofer, Christoph; Palti, Eran; Till, Oskar; Weigand, Timo

    2015-06-01

    We study the relation between discrete gauge symmetries in F-theory compactifications and torsion homology on the associated Calabi-Yau manifold. Focusing on the simplest example of a symmetry, we show that there are two physically distinct ways that such a discrete gauge symmetry can arise. First, compactifications of M-Theory on Calabi-Yau threefolds which support a genus-one fibration with a bi-section are known to be dual to six-dimensional F-theory vacua with a gauge symmetry. We show that the resulting five-dimensional theories do not have a symmetry but that the latter emerges only in the F-theory decompactification limit. Accordingly the genus-one fibred Calabi-Yau manifolds do not exhibit torsion in homology. Associated to the bi-section fibration is a Jacobian fibration which does support a section. Compactifying on these related but distinct varieties does lead to a symmetry in five dimensions and, accordingly, we find explicitly an associated torsion cycle. We identify the expected particle and membrane system of the discrete symmetry in terms of wrapped M2 and M5 branes and present a field-theory description of the physics for both cases in terms of circle reductions of six-dimensional theories. Our results and methods generalise straightforwardly to larger discrete symmetries and to four-dimensional compactifications.

  5. ``Quasi-complete'' mechanical model for a double torsion pendulum

    NASA Astrophysics Data System (ADS)

    De Marchi, Fabrizio; Pucacco, Giuseppe; Bassan, Massimo; De Rosa, Rosario; Di Fiore, Luciano; Garufi, Fabio; Grado, Aniello; Marconi, Lorenzo; Stanga, Ruggero; Stolzi, Francesco; Visco, Massimo

    2013-06-01

    We present a dynamical model for the double torsion pendulum nicknamed “PETER,” where one torsion pendulum hangs in cascade, but off axis, from the other. The dynamics of interest in these devices lies around the torsional resonance, that is at very low frequencies (mHz). However, we find that, in order to properly describe the forced motion of the pendulums, also other modes must be considered, namely swinging and bouncing oscillations of the two suspended masses, that resonate at higher frequencies (Hz). Although the system has obviously 6+6 degrees of freedom, we find that 8 are sufficient for an accurate description of the observed motion. This model produces reliable estimates of the response to generic external disturbances and actuating forces or torques. In particular, we compute the effect of seismic floor motion (“tilt” noise) on the low frequency part of the signal spectra and show that it properly accounts for most of the measured low frequency noise.

  6. Shape sensing for torsionally compliant concentric-tube robots

    NASA Astrophysics Data System (ADS)

    Xu, Ran; Yurkewich, Aaron; Patel, Rajni V.

    2016-03-01

    Concentric-tube robots (CTR) consist of a series of pre-curved flexible tubes that make up the robot structure and provide the high dexterity required for performing surgical tasks in constrained environments. This special design introduces new challenges in shape sensing as large twisting is experienced by the torsionally compliant structure. In the literature, fiber Bragg grating (FBG) sensors are attached to needle-sized continuum robots for curvature sensing, but they are limited to obtaining bending curvatures since a straight sensor layout is utilized. For a CTR, in addition to bending curvatures, the torsion along the robots shaft should be determined to calculate the shape and pose of the robot accurately. To solve this problem, in our earlier work, we proposed embedding FBG sensors in a helical pattern into the tube wall. The strain readings are converted to bending curvatures and torsion by a strain-curvature model. In this paper, a modified strain-curvature model is proposed that can be used in conjunction with standard shape reconstruction algorithms for shape and pose calculation. This sensing technology is evaluated for its accuracy and resolution using three FBG sensors with 1 mm sensing segments that are bonded into the helical grooves of a pre-curved Nitinol tube. The results show that this sensorized robot can obtain accurate measurements: resolutions of 0.02 rad/m with a 100 Hz sampling rate. Further, the repeatability of the obtained measurements during loading and unloading conditions are presented and analyzed.

  7. Oligothiophene wires: impact of torsional conformation on the electronic structure.

    PubMed

    Kislitsyn, D A; Taber, B N; Gervasi, C F; Zhang, L; Mannsfeld, S C B; Prell, J S; Briseno, A L; Nazin, G V

    2016-02-14

    Charge transport in polymer- and oligomer-based semiconductor materials depends strongly on the structural ordering of the constituent molecules. Variations in molecular conformations influence the electronic structures of polymers and oligomers, and thus impact their charge-transport properties. In this study, we used Scanning Tunneling Microscopy and Spectroscopy (STM/STS) to investigate the electronic structures of different alkyl-substituted oligothiophenes displaying varied torsional conformations on the Au(111) surface. STM imaging showed that on Au(111), oligothiophenes self-assemble into chain-like structures, binding to each other via interdigitated alkyl ligands. The molecules adopted distinct planar conformations with alkyl ligands forming cis- or trans- mutual orientations. For each molecule, by using STS mapping, we identify a progression of particle-in-a-box-like states corresponding to the LUMO, LUMO+1 and LUMO+2 orbitals. Analysis of STS data revealed very similar unoccupied molecular orbital energies for different possible molecular conformations. By using density functional theory calculations, we show that the lack of variation in molecular orbital energies among the different oligothiophene conformers implies that the effect of the Au-oligothiophene interaction on molecular orbital energies is nearly identical for all studied torsional conformations. Our results suggest that cis-trans torsional disorder may not be a significant source of electronic disorder and charge carrier trapping in organic semiconductor devices based on oligothiophenes. PMID:26804474

  8. Development of a torsion balance for adhesion measurements

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa; Maeda, Chikayoshi; Masuo, Ryuichi

    1988-01-01

    A new torsion balance for study of adhesion in ceramics is discussed. A torsion wire and a linear variable differential transformer are used to monitor load and to measure pull-off force (adhesion force). The investigation suggests that this torsion balance is valuable in studying the interfacial properties of ceramics in controlled environments such as in ultrahigh vacuum. The pull-off forces measured in dry, moist, and saturated nitrogen atmosphere demonstrate that the adhesion of silicon nitride contacts remains low at humidities below 80 percent but rises rapidly above that. The adhesion at saturation is 10 times or more greater than that below 80 percent relative humidity. The adhesion in a saturated atmosphere arises primarily from the surface tension effects of a thin film of water adsorbed on the surface. The surface tension of the water film was 58 x 10 to the minus 5 to 65 x 10 to the minus 5 power. The accepted value for water is 72.7 x 10 to the minus 5 power N/cm. Adhesion characteristics of silicon nitride in contact with metals, like the friction characteristics of silicon carbide to metal contacts, can be related to the relative chemical activity of metals in ultrahigh vacuum. The more active the metal, the higher the adhesion.

  9. The dynamics and excitation of torsional waves in geodynamo simulations

    NASA Astrophysics Data System (ADS)

    Teed, R. J.; Jones, C. A.; Tobias, S. M.

    2014-02-01

    The predominant force balance in rapidly rotating planetary cores is between Coriolis, pressure, buoyancy and Lorentz forces. This magnetostrophic balance leads to a Taylor state where the spatially averaged azimuthal Lorentz force is compelled to vanish on cylinders aligned with the rotation axis. Any deviation from this state leads to a torsional oscillation, signatures of which have been observed in the Earth's secular variation and are thought to influence length of day variations via angular momentum conservation. In order to investigate the dynamics of torsional oscillations (TOs), we perform several 3-D dynamo simulations in a spherical shell. We find TOs, identified by their propagation at the correct Alfvén speed, in many of our simulations. We find that the frequency, location and direction of propagation of the waves are influenced by the choice of parameters. Torsional waves are observed within the tangent cylinder and also have the ability to pass through it. Several of our simulations display waves with core traveltimes of 4-6 yr. We calculate the driving terms for these waves and find that both the Reynolds force and ageostrophic convection acting through the Lorentz force are important in driving TOs.

  10. LISA technology development using the UF precision torsion pendulum

    NASA Astrophysics Data System (ADS)

    Apple, Stephen; Chilton, Andrew; Olatunde, Taiwo; Ciani, Giacomo; Mueller, Guido; Conklin, John

    2015-04-01

    LISA will directly observe low-frequency gravitational waves emitted by sources ranging from super-massive black hole mergers to compact galactic binaries. A laser interferometer will measure picometer changes in the distances between free falling test masses separated by millions of kilometers. A test mass and its associated sensing, actuation, charge control and caging subsystems are referred to as a gravitational reference sensor (GRS). The demanding acceleration noise requirement for the LISA GRS has motivated a rigorous testing campaign in Europe and a dedicated technology mission, LISA Pathfinder, scheduled for launch in the fall of 2015. At the University of Florida we are developing a nearly thermally noise limited torsion pendulum for testing GRS technology enhancements that may improve the performance and/or reduce the cost of the LISA GRS. This experimental facility is based on the design of a similar facility at the University of Trento, and consists of a vacuum enclosed torsion pendulum that suspends mock-ups of the LISA test masses, surrounded by electrode housings. Some of the technologies that will be demonstrated by this facility include a novel TM charge control scheme based on ultraviolet LEDs, an all-optical TM position and attitude sensor, and drift mode operation. This presentation will describe the design of the torsion pendulum facility, its current acceleration noise performance, and the status of the GRS technologies under development.

  11. Topological Behavior of Plasmid DNA

    PubMed Central

    Higgins, N. Patrick; Vologodskii, Alexander V.

    2015-01-01

    The discovery of the B-form structure of DNA by Watson and Crick led to an explosion of research on nucleic acids in the fields of biochemistry, biophysics, and genetics. Powerful techniques were developed to reveal a myriad of different structural conformations that change B-DNA as it is transcribed, replicated, and recombined and as sister chromosomes are moved into new daughter cell compartments during cell division. This article links the original discoveries of superhelical structure and molecular topology to non-B form DNA structure and contemporary biochemical and biophysical techniques. The emphasis is on the power of plasmids for studying DNA structure and function. The conditions that trigger the formation of alternative DNA structures such as left-handed Z-DNA, inter- and intra-molecular triplexes, triple-stranded DNA, and linked catenanes and hemicatenanes are explained. The DNA dynamics and topological issues are detailed for stalled replication forks and for torsional and structural changes on DNA in front of and behind a transcription complex and a replisome. The complex and interconnected roles of topoisomerases and abundant small nucleoid association proteins are explained. And methods are described for comparing in vivo and in vitro reactions to probe and understand the temporal pathways of DNA and chromosome chemistry that occur inside living cells. PMID:26104708

  12. Rotational Energies in Various Torsional Levels of CH_2DOH

    NASA Astrophysics Data System (ADS)

    Coudert, L. H.; Hilali, A. El; Margulès, L.; Motiyenko, R. A.; Klee, S.

    2012-06-01

    Using an approach accounting for the hindered internal rotation of a monodeuterated methyl group, an analysis of the torsional spectrum of the monodeuterated species of methanol CH_2DOH has been carried out recently and led to the assignment of 76 torsional subbands in its microwave, FIR, and IR spectra. Although this approach also allowed us to account for subband centers, the rotational structure of the torsional subbands is not well understood yet. In this paper, we will deal with the rotational energies of CH_2DOH. Analyses of the rotational structure of the available subbands^b have been performed using the polynomial-type expansion introduced in the case of the normal species of methanol. For each subband, FIR or IR transitions and a-type microwave lines, within the lower torsional level, were fitted. The frequencies of the latters were taken from previous investigations or from new measurements carried out from 50 to 950 GHz with the submillimeterwave solid state spectrometer in Lille. Subbands involving lower levels with v_t=0 and K ≥ 3 could be satisfactorily analyzed. For levels characterized by lower K-values, the expansion fails. In the case of the K=1, v_t=1 level, the frequencies of a-type microwave transitions involving the lower member of the K-type doublet cannot be well reproduced. For K=0 levels with v_t=1 and 2, a large number of terms is needed in the expansion. We will try to understand why the rotational energies of these levels cannot be reproduced. The results of the analyses will be compared to those obtained with a global approach based on the rotation-torsion Hamiltonian of the molecule. [2] El Hilali, Coudert, Konov, and Klee, J. Chem. Phys. 135 (2011) 194309. [3] Ioli, Moruzzi, Riminucci, Strumia, Moraes, Winnewisser, and Winnewisser, J. Mol. Spec. 171 (1995) 130. [4] Quade and Suenram, J. Chem. Phys. 73 (1980) 1127; and Su and Quade, J. Mol. Spec. 134 (1989) 290. [5] Lauvergnat, Coudert, Klee, and Smirnov, J. Mol. Spec. 256 (2009

  13. Torsion sensing characteristics of long period fiber gratings fabricated by femtosecond laser in optical fiber

    NASA Astrophysics Data System (ADS)

    Duan, Ji'an; Xie, Zheng; Wang, Cong; Zhou, Jianying; Li, Haitao; Luo, Zhi; Chu, Dongkai; Sun, Xiaoyan

    2016-09-01

    With the alignment of the fiber core systems containing dual-CCDs and high-precision electric displacement platform, twisted long period fiber gratings (T-LPFGs) were fabricated in two different twisted SMF-28 fibers by femtosecond laser. The torsion characteristics of the T-LPFGs were experimentally and theoretical investigated and demonstrated in this study. The achieved torsion sensitivity is 117.4 pm/(rad/m) in the torsion range -105-0 rad/m with a linearity of 0.9995. Experimental results show that compared with the ordinary long period fiber gratings, the resonance wavelength of the gratings presents an opposite symmetrical shift depending on the twisting direction after the applied torsion is removed. In addition, high sensitivity could be obtained, which is very suitable for the applications in the torsion sensor. These results are important for the design of new torsion sensors based on T-LPFGs fabricated by femtosecond laser.

  14. Improving the sensitivity of a torsion pendulum by using an optical spring method

    SciTech Connect

    Wang Qinglan; Yeh Hsienchi; Zhou Zebing; Luo Jun

    2009-10-15

    We present a scheme aiming at improving the sensitivity of a torsion pendulum by means of radiation-pressure-induced optical spring. Two partial-reflective mirrors are installed on the opposite sides of a torsion pendulum, and one high-reflective mirror is mounted at the end of the torsion beam so that two identical Fabry-Perot cavities can be formed and aligned in series. Due to the antisymmetric radiation pressures acting on the opposite sides of the torsion beam, a negative restoring coefficient can be generated within a certain dynamic range, such that both the resultant torsional rigidity and the resonant frequency of the torsion pendulum are reduced, and the minimum detectable response torque in high-frequency region can be reduced accordingly.

  15. Axial and torsional fatigue behavior of a cobalt-base alloy

    NASA Technical Reports Server (NTRS)

    Bonacuse, Peter J.; Kalluri, Sreeramesh

    1991-01-01

    In order to develop elevated temperature multiaxial fatigue life prediction models for the wrought cobalt-base alloy, Haynes 188, a multiaxial fatigue data base is required. To satisfy this need, an elevated temperature experimental program on Haynes 188 consisting of axial, torsional, inphase and out of phase axial-torsional fatigue experiments was designed. Elevated temperature axial and torsional fatigue experiments were conducted under strain control on thin wall tubular specimens of Haynes 188 in air. Test results are given.

  16. Eye torsion and visual tilt are mediated by different binocular processes

    NASA Technical Reports Server (NTRS)

    Wolfe, J. M.; Held, R.

    1979-01-01

    Viewing a large, patterned field rotating about the line of sight produces two measurable effects; cyclotorsion of the eyes (torsion) and a perceived displacement of vertical and horizontal (tilt). Experiments examining binocular interaction for these effects show: (1) both effects demonstrate summation in normal individuals and thus both involve a binocular process; (2) the process for tilt is different than for torsion, since summation for torsion is spared in stereodeficient individuals while that for tilt is eliminated.

  17. Weakly-Interacting Massive Particles in Torsionally-Gravitating Dirac Theory

    NASA Astrophysics Data System (ADS)

    Fabbri, Luca

    2013-08-01

    We shall consider the problem of Dark Matter (DM) in torsion gravity with Dirac matter fields; we will consider the fact that if Weakly-Interacting Massive Particles in a bath are allowed to form condensates then torsional effects may be relevant even at galactic scales: we show that torsionally-gravitating Dirac fields have interesting properties for the problem of DM. We discuss consequences.

  18. Appendiceal torsion associated with undescended caecum: a case report and review of the literature

    PubMed Central

    Dimitriadis, Panagiotis A; Makar, Ragai R; Randall, Jon K; Ramus, James

    2012-01-01

    Torsion of the vermiform appendix is a rare disorder that causes symptoms similar to those of acute appendicitis. Primary and secondary causes of appendiceal torsion have been reported in the literature. Laparoscopy appears to be the most appropriate modality for diagnosis and treatment where the condition is suspected. To our knowledge this is the first case of appendiceal torsion in an adult causing right upper quadrant pain related to caecal malposition. PMID:23010467

  19. Application of a boundary element method to the study of dynamical torsion of beams

    NASA Technical Reports Server (NTRS)

    Czekajski, C.; Laroze, S.; Gay, D.

    1982-01-01

    During dynamic torsion of beam elements, consideration of nonuniform warping effects involves a more general technical formulation then that of Saint-Venant. Nonclassical torsion constants appear in addition to the well known torsional rigidity. The adaptation of the boundary integral element method to the calculation of these constants for general section shapes is described. The suitability of the formulation is investigated with some examples of thick as well as thin walled cross sections.

  20. Use of Generalized Mass in the Interpretation of Dynamic Response of BENDING-TORSION Coupled Beams

    NASA Astrophysics Data System (ADS)

    ESLIMY-ISFAHANY, S. H. R.; BANERJEE, J. R.

    2000-11-01

    The interpretation of mode shapes and dynamic response of bending-torsion coupled beams is assessed by using the concept of generalized mass. In the first part of this investigation, the free vibratory motion of bending-torsion coupled beams is studied in detail. The conventional method of interpreting the normal modes of vibration consisting of bending displacements and torsional rotations is shown to be inadequate and replaced by an alternative method which is focussed on the constituent parts of the generalized mass arising from bending and torsional displacements. Basically, the generalized mass in a particular mode is identified and examined in terms of bending, torsion and bending-torsion coupling effects. It is demonstrated that the contribution of individual components in the expression of the generalized mass of a normal mode is a much better indicator in characterizing a coupled mode. It is also shown that the usually adopted criteria of plotting bending displacement and torsional rotations to describe a coupled mode can be deceptive and misleading. In the second part of the investigation, attention is focussed on the dynamic response characteristics of bending-torsion coupled beams when subjected to random bending or torsional loads. A normal mode approach is used to establish the total response. The input random excitation is assumed to be stationary and ergodic so that with the linearity assumption, the output spectrum of the response is obtained by using the frequency response function. The contribution of each normal mode to the overall response is isolated. Particular emphasis is placed on bending-induced torsional response and torsion-induced bending response. A number of case studies involving different types of bending-torsion coupled beams with Cantilever end conditions are presented. The limitations of existing methods of modal interpretation are highlighted, and an insight into the mode selection for response analysis is provided.

  1. Extended torsional tests of an interlocked bi-stem satellite boom

    NASA Technical Reports Server (NTRS)

    Abercrombie, R. A.

    1973-01-01

    The effect is reported of continued oscillations of a 1.27-cm interlocked bi-stem satellite boom. The test setup oscillated a boom continuously between set torque limits and periodically recorded its hysteresis characteristics. Results showed that repeated oscillations affected torsional characteristics and that torsional rigidity changed as a function of the number of cycles oscillated within certain torque limits. Torsional characteristics changes caused by repeated oscillations were retained.

  2. 3D Curves With a Prescribed Curvature and Torsion for a Flying Robot

    SciTech Connect

    Bestaoui, Yasmina

    2008-06-12

    The objective of this paper is to generate a desired flight path to be followed by an flying robot. A curve with discontinuous curvature and torsion is not appropriate for smooth motions for any vehicle architecture. Three different classes of curves are presented. First, constant curvature and torsion followed by a linear variation versus the curvilinear abscissa then a quadratic variation. Finally, the problem of maneuvers between two trim helices of different curvature and torsion is tackled with.

  3. The propagation of torsion along flux tubes subject to dynamical nonequilibrium

    NASA Technical Reports Server (NTRS)

    Parker, E. N.

    1983-01-01

    It is noted that the dynamical nonequilibrium of close-packed flux tubes is driven by the torsion in the individual tubes. Because of this, whenever tubes with the same sense of twisting come into contact, there is reconnection of their azimuthal field components. The reconnection consumes the local torsion, and this causes the propagation of torsional Alfven waves into the region from elsewhere along the tubes. The formal problem of the propagation of the torsion along twisted flux tubes is presented, along with some of the basic physical properties worked out in the limit of small torsion. It is noted that in tubes with finite twisting the propagation of torsional Alfven waves can be a more complicated phenomenon. Application to the sun suggests that the propagation of torsion from below the visible surface up into the corona is an important energy supply to the corona for a period of perhaps 10-20 hours after the emergence of the flux tubes through the surface of the sun, bringing up torsion from depths of 10,000 km or more. Torsion is of course continually furnished by the manipulation and shuffling of the field by the convection.

  4. Torsion of a mucocele of the vermiform appendix: a case report and review of the literature

    PubMed Central

    Lee, Chang Ho; Lee, Min Ro; Kim, Jae-Chun; Kang, Myoung Jae

    2011-01-01

    Torsion of a mucocele of the vermiform appendix is an extremely rare condition and also a rare cause of an acute abdomen with a clinical presentation that is indistinguishable from acute appendicitis, and thus, the condition is diagnosed during operation. Here, the authors describe the case of a 78-year-old female, who presented with intermittent abdominal pain. The appendix had a pelvic position and the torsion was counterclockwise. In addition, the torsion was associated with mucocele of the appendix, which was considered a secondary factor of torsion. Appendectomy and drainage were performed. PMID:22319738

  5. On mechanical properties of square and rectangular stainless steel wires tested in torsion.

    PubMed

    Meling, T R; Odegaard, J; Meling, E O

    1997-03-01

    Forty different sizes and types of square and rectangular stainless steel wires, supplied by five different manufacturers, were tested in torsion. The study simulated the situation occurring when torque is applied to an individual tooth. We used standard brackets with 0.018-inch slot heights, with an interbracket distance of 4 mm. The results show that variation in cross-sectional dimension and edge bevel leads to variable torsional play (third-order clearance). As an example 0.016 x 0.022-inch wires have a mean torsional play of as much as 18.5 degrees, with a range of 16.6 degrees to 20.4 degrees. We have shown that when 0.016 x 0.022-inch wires are used, one must apply from 24.6 degrees to 29.2 degrees of twist to get 20 Nmm of torsional moment. This variation is mostly due to a rather wide range in torsional play. As a result, the prediction by which a predetermined torsional moment can be delivered becomes uncertain. The results show that because the working range in torsion of stainless steel wires is somewhat limited, precise delivery of torsional moment, based on the condition present in the oral cavity, is difficult. Torsional stiffness varies considerable within the various dimensional groups, this being the result of variation in cross-sectional geometry and material properties. PMID:9082854

  6. Influence of braiding structure on torsional properties of braided composite tube

    SciTech Connect

    Nakai, A.; Hamada, H.; Hoa, S.V.

    1996-12-01

    Many different composite cylinders and pipes can be produced by various fabrication methods such as filament winding, prepreg rolling method, braiding technique and so on. It is desirable to understand the mechanical behavior of pipe made by the different method. In this paper torsional behavior of braided composite tube, particularly the effects of braiding angle, was investigated. Numerical model was applied to estimate the torsional rigidity. The torsional rigidity increases with increase of braiding angle from 30{degree} to 45{degree}. However above 45{degree} braiding angle the torsional rigidity remains constant. These results can be compared to numerical results.

  7. Gravitational waves and magnetic monopoles during inflation with Weitzenböck torsion

    NASA Astrophysics Data System (ADS)

    Romero, Jesús Martín; Bellini, Mauricio; Aguilar, José Edgar Madriz

    2016-09-01

    We study the variational principle on a Hilbert-Einstein action in an extended geometry with torsion taking into account non-trivial boundary conditions. We obtain an effective energy-momentum tensor that has its source in the torsion, which represents the matter geometrically induced. We explore about the existence of magnetic monopoles and gravitational waves in this torsional geometry. We conclude that the boundary terms can be identified as possible sources for the cosmological constant and torsion as the source of magnetic monopoles. We examine an example in which gravitational waves are produced during a de Sitter inflationary expansion of the universe.

  8. Torsion-sensing material from aligned carbon nanotubes wound onto a rod demonstrating wide dynamic range.

    PubMed

    Yamada, Takeo; Yamamoto, Yuki; Hayamizu, Yuhei; Sekiguchi, Atsuko; Tanaka, Hiroyuki; Kobashi, Kazufumi; Futaba, Don N; Hata, Kenji

    2013-04-23

    A rational torsion sensing material was fabricated by wrapping aligned single-walled carbon nanotube (SWCNT) thin films onto the surface of a rod with a predetermined and fixed wrapping angle without destroying the internal network of the SWCNTs within the film. When applied as a torsion sensor, torsion could be measured up to 400 rad/meter, that is, more than 4 times higher than conventional optical fiber torsion sensors, by monitoring increases in resistance due to fracturing of the aligned SWCNT thin films. PMID:23464614

  9. Effect of Different Levels of Pressure Relieving Air-Mattress Firmness on Cough Strength

    PubMed Central

    Kamikawa, Norimichi; Taito, Shunsuke; Takahashi, Makoto; Sekikawa, Kiyokazu; Hamada, Hironobu

    2016-01-01

    Cough is an important host-defense mechanism. The elderly and patients who are severely ill cannot cough effectively when lying in the supine position. Furthermore, pressure relieving air-mattresses are recommended for preventing the development of pressure ulcers. In this study, we clarified whether or not the cough peak flow (CPF), an index of cough strength, is affected by different firmness levels of a pressure relieving air-mattress in healthy volunteers in the supine position. Fifty-two healthy young men participated. All the measurements were carried out on each participant in the supine position on a pressure relieving air-mattress. The participants were assessed at two firmness levels, a “hard” and “soft” mode. The CPF, forced vital capacity (FVC), maximal expiratory pressure (PEmax), and maximal inspiratory pressure (PImax) were determined for each mode. The sinking distance of the body into the mattress was measured without any activity and the difference between the sinking distances of the two firmness levels was determined. The CPF, FVC, PEmax, and PImax were determined for each mode. The sinking distance of the body into the mattress was measured and the difference between the sinking distances of the two firmness levels was determined. The CPF, FVC, PEmax and PImax values of the participants coughing on the mattress were significantly lower when the mattress was in “soft” than in “hard” mode. The differences between the sinking distances of the mattress in “soft” and “hard” modes were larger for the anterior superior iliac spine. A harder mattress may lead to increased CPF in healthy young men lying in the supine position, and increased CPF may be important for host defense. PMID:26741497

  10. Effect of Different Levels of Pressure Relieving Air-Mattress Firmness on Cough Strength.

    PubMed

    Kamikawa, Norimichi; Taito, Shunsuke; Takahashi, Makoto; Sekikawa, Kiyokazu; Hamada, Hironobu

    2016-01-01

    Cough is an important host-defense mechanism. The elderly and patients who are severely ill cannot cough effectively when lying in the supine position. Furthermore, pressure relieving air-mattresses are recommended for preventing the development of pressure ulcers. In this study, we clarified whether or not the cough peak flow (CPF), an index of cough strength, is affected by different firmness levels of a pressure relieving air-mattress in healthy volunteers in the supine position. Fifty-two healthy young men participated. All the measurements were carried out on each participant in the supine position on a pressure relieving air-mattress. The participants were assessed at two firmness levels, a "hard" and "soft" mode. The CPF, forced vital capacity (FVC), maximal expiratory pressure (PEmax), and maximal inspiratory pressure (PImax) were determined for each mode. The sinking distance of the body into the mattress was measured without any activity and the difference between the sinking distances of the two firmness levels was determined. The CPF, FVC, PEmax, and PImax were determined for each mode. The sinking distance of the body into the mattress was measured and the difference between the sinking distances of the two firmness levels was determined. The CPF, FVC, PEmax and PImax values of the participants coughing on the mattress were significantly lower when the mattress was in "soft" than in "hard" mode. The differences between the sinking distances of the mattress in "soft" and "hard" modes were larger for the anterior superior iliac spine. A harder mattress may lead to increased CPF in healthy young men lying in the supine position, and increased CPF may be important for host defense. PMID:26741497

  11. Ispaghula husk may relieve gastrointestinal symptoms in ulcerative colitis in remission.

    PubMed

    Hallert, C; Kaldma, M; Petersson, B G

    1991-07-01

    The efficiency of ispaghula husk in relieving gastrointestinal symptoms in patients with ulcerative colitis in remission was studied in a placebo-controlled trial running for 4 months. Twenty-nine patients (81%) completed the trial; four withdrew after colitis relapse (three while receiving placebo). Grading of symptoms judged ispaghula to be consistently superior to placebo (p less than 0.001) and associated with a significantly higher rate of improvement (69%) than placebo (24%) (p less than 0.001). The results show that ispaghula can be helpful in the management of gastrointestinal symptoms in quiescent ulcerative colitis. PMID:1654592

  12. Botulinum toxin A relieved neuropathic pain in a case of post-herpetic neuralgia.

    PubMed

    Liu, Hsu-Tang; Tsai, Shen-Kou; Kao, Ming-Chang; Hu, Jenkin S

    2006-01-01

    Botulinum toxin type A (BTX-A) has been widely used in many clinical disorders including migraine, cervical dystonia, etc. The use of BTX-A in neuropathic pain, however, is uncommon, and the application of the anti-nociceptive effect of botulinum toxin is emerging. Here we report a case of an 80-year-old man who suffered from severe pain of post-herpetic neuralgia which was refractory to the usual therapies. However, this neuropathic pain was dramatically relieved by multiple BTX-A injection and the pain relief lasted 52 days. PMID:16533208

  13. Fluorescence spectroscopic studies of DNA dynamics

    SciTech Connect

    Scalettar, B.A.

    1987-04-01

    Random solvent induced motions of DNA are manifest as nanosecond torsional oscillations of the helix backbone, nanosecond through millisecond bending deformations and overall rotational and translational diffusion of the polymer. Fluorescence spectroscopy is used to study this spectrum of DNA motions while ethidium monoazide was covalently bounded. The steady state fluorescence depolarization data indicate that the covalent monoazide/DNA complex exhibits internal motions characterized by an average angular amplitude of 26 degrees confirming reports of fast torsional oscillations in noncovalent ethidium bromide/DNA systems. Data obtained by use of a new polarized photobleaching recovery technique (FPR) reflect both the rotational dynamics of the polymer and the reversible photochemistry of the dye. To isolate the reorientational motion of the DNA, the FPR experiments were ran in two modes that differ only in the polarization of the bleaching light. A quotient function constructed from the data obtained in these two modes monitors only the rotational component of the FPR recovery. In specific applications those bending deformations of long DNA molecules that have characteristic relaxation times on the order of 100 microseconds have been resolved. A fluorescence correlation technique that relates fluctuations in particle number to center-of-mass motion was used to measure translational diffusion on coefficients of the plasmid PBR322 and a short oligomeric DNA. A theory that describes angular correlation in systems exhibiting cyclic, biologically directed reorientation and random Brownian rotation is developed.

  14. Fatigue strength of adhesive bonded section beams under torsion

    SciTech Connect

    Tomioka, Noboru; Kakiage, Masashi; Niisawa, Junetsu; Kitagawa, Hideo

    1995-11-01

    Fatigue strength of adhesive bonded box beams was investigated. From results of the fatigue tests, it was seen that the fatigue strength of bonded beams was higher than that of spot welded beams. Fatigue strength of bonded beams was independent of plate thickness and partition. The flexural rigidity of the box beams in the plane of partition can increase without decrease of torsional rigidity and torsional fatigue strength, if the partition is jointed by adhesive bonding instead of spot welding. Since the fatigue strength and rigidity of adhesive bonded joints can be higher than the spot welded joints in the weight saving structures, it is expected that the structural adhesive joints will be employed more in the automobile body structure. For assuring the introduction of this joint more into the automobile body structures, it is necessary that the fatigue tests on the model members of the actual members used in the automobile body structure are conducted, in addition to those of the simple joints such as tension shear and T-type tension, and the property of the fatigue strength on the adhesive bonded members is known. But, the authors now have little data on fatigue tests of the adhesive bonded members. In the present research to be reported, the fatigue tests on adhesive bonded box beams under torsion, which are typical members in automobile body structure, were carried out and the effects of the presence of longitudinal partition and plate thickness on fatigue strength were investigated. Comparing the results of fatigue tests on adhesive bonded box beams with those on spot welded box beams, the property of fatigue strength on these adhesive bonded box beams was cleared.

  15. Topoisomerase I-mediated DNA damage.

    PubMed

    Pourquier, P; Pommier, Y

    2001-01-01

    Topoisomerase I is a ubiquitous and essential enzyme in multicellular organisms. It is involved in multiple DNA transactions including DNA replication, transcription, chromosome condensation and decondensation, and probably DNA recombination. Besides its activity of DNA relaxation necessary to eliminate torsional stresses associated with these processes, topoisomerase I may have other functions related to its interaction with other cellular proteins. Topoisomerase I is the target of the novel anticancer drugs, the camptothecins. Recently a broad range of physiological and environmentally-induced DNA modifications have also been shown to poison topoisomerases. This review summarizes the various factors that enhance or suppress top1 cleavage complexes and discusses the significance of such effects. We also review the different mechanisms that have been proposed for the repair of topoisomerase I-mediated DNA lesions. PMID:11034544

  16. Plastic welding techniques based on torsional and circular motion.

    PubMed

    Kising, J

    2001-05-01

    The torsion ultrasonic welding process and the frequency decoupled circular friction process at low frequencies deliver low particle production. In addition, the even, circular movement of the circular welding process over the whole seam area and the freely selectable frequency open up applications in the medical field that cannot be achieved, or can only be achieved with difficulty, by traditional welding processes. The processes are fast and can be process controlled to a fine degree with a facility to be integrated into automation lines. PMID:11521653

  17. Damping in coupled bending and torsion - An experiment

    NASA Technical Reports Server (NTRS)

    Umland, Jeffrey W.; Inman, Daniel J.; Banks, H. T.

    1991-01-01

    Traditional experimental modal testing methods are used to determine the damping properties of a Euler-Bernoulli beam with offset inertial tip mass. Both viscous and strain rate damping models are considered in bending and in torsion. A partial differential equation model of the coupled system is used. Eigenfunctions are derived for the coupled system by using a Green's function approach to derive the approximate uncoupled eigenfunctions. These eigenfunctions are used in a decoupled fashion with experimental modal data to estimate the damping parameters of the coupled system. The experimental modal data were obtained from both free and impulse responses using a combined translational and rotational accelerometer.

  18. Slip measurement in a frictional connection by torsional LDV

    NASA Astrophysics Data System (ADS)

    Schäfer, Günter; Lohrengel, Armin; Hilgermann, Jan Lukas

    2016-06-01

    Frictional shaft-hub connections are often used in drive train applications. The classic version is fitted by a temperature difference between the cold shaft und the hot hub, or simply axial press-fitted at room temperature. The critical point in this type of connection is the contact pressure at the edge of the hub regarding the relative deformation between the shaft and the hub under dynamic operating loads. Another innovative version, the internal press-fit, leads to a tolerance insensitive lightweight design using a tube as shaft and a controlled plastic deformation by internal high pressure. The internal press-fit connection is a special research topic at the IMW, TU Clausthal. The use of internal high pressure allows to trigger the contact pressure at the edge of the hub on an optimum value. The product of contact pressure and slipway is the key value to determine the fatigue resistance and load capacity of this kind of connection. /1/ and /2/ defined a critical range of slipway amplitudes between 5 and 25 µm for fretting. The normal use and main function of a shaft-hub connection is the transmission of torque. Regarding the different torsional stiffness of the shaft and the hub, there will be a difference in deformation in the contact zone between the shaft and the hub, which is necessary to measure on a probe under oscillating torque load. The measurement on the test-rig in /3/ was done with a POLYTEC torsional LDV (controller OFV-4000, sensor head OFV-400). In general the continuously oscillating torque load allowed a serial measurement of the torsional movement of the shaft and the hub. The difference of the two maximum values is the expected slipway between the two parts in the critical zone at the edge of the hub. The main benefits of the Torsional LDV in this application are the very small measuring point (next to the contact), no influence on the probe, no special preparation of the probe and a really good resolution. The paper gives an overview to

  19. Torsional mode relaxation of DABCO in a seeded supersonic beam

    NASA Astrophysics Data System (ADS)

    Wang, Z. W.; Quesada, M. A.; Parker, D. H.

    1987-10-01

    DABCO's ν 13 torsional mode relaxation is monitored in a helium-DABCO and argon-DABCO supersonic jet under low expansion conditions. Both cw and pulsed nozzles are employed. Modeling of the relaxation using the linear Landau-Teller relaxation equation is undertaken with various attempts to incorporate the effects of velocity slip. The relaxation rate is found to be independent of slip and the cross section dependent on the inverse of translational temperature. A V → R process is suggested as the rate determining mechanism.

  20. [Ovarian torsion revealing an ovarian cavernous hemangioma in a child].

    PubMed

    M'pemba Loufoua-Lemay, A-B; Peko, J-F; Mbongo, J-A; Mokoko, J-C; Nzingoula, S

    2003-11-01

    The authors report one case of cavernous hemangioma of the left ovary, which was revealed by ovarian torsion. Such benign tumors of the blood vessels are rare in ovaries during childhood. This hemangioma was observed in a 13-year-old patient, who presented with abdominal and pelvic pain and vomiting. The pelvic mass was noted and sonography revealed a cystic tumor. An annexectomia was realized. Histology showed narcotized ovary cells, with an increased number of vascular channels composed of thin walled vessels, whose wall consisted of an endothelium. This aspect evoked a cavernous hemangioma of the ovary. PMID:14613693

  1. Compressional and torsional wave amplitudes in rods with periodic structures

    NASA Astrophysics Data System (ADS)

    Morales, A.; Flores, J.; Gutierrez, L.; Mendez-Sanchez, R. A.

    2002-11-01

    To measure and detect elastic waves in metallic rods a low-frequency electromagnetic-acoustic transducer has been developed. Frequencies range from a few hertz up to hundreds of kilohertz. With appropriate configuration of the transducer, compressional or torsional waves can be selectively excited or detected. Although the transducer can be used in many different situations, it has been tested and applied to a locally periodic rod, which consists of a finite number of unit cells. The measured wave amplitudes are compared with theoretical ones, obtained with the one-dimensional transfer matrix method, and excellent agreement is obtained. copyright 2002 Acoustical Society of America.

  2. Photoelectronic vibrometer with polarized light. [for torsional vibration measurements

    NASA Technical Reports Server (NTRS)

    Kremmer, I.

    1974-01-01

    A seismic torsiometer is described which is based on the reception by a photosensitive transducer of a light flux modulated by a relative rotation of the optical axes of two polaroids. The torsional vibrations of the polaroid fixed to the shaft are transmitted to the other polaroid (which at the same time is the seismic mass of the apparatus) by means of elastic lamellas. The device can work as accelerometer, vibrometer or frequency meter, depending on the value of the ratio between the proper oscillation frequency of the seismic system and the measured vibration frequency.

  3. Yeast phenylalanine transfer RNA: atomic coordinates and torsion angles.

    PubMed Central

    Quigley, G J; Seeman, N C; Wang, A H; Suddath, F L; Rich, A

    1975-01-01

    The atomic coordinates of yeast phenylalanine transfer RNA (tRNA) as well as the torsion angles of the polynucleotide chain are presented as derived from an x-ray diffraction analysis of orthorhombic crystals. A comparison is made between the coordinates obtained from analysis of monoclinic crystals of the same material. It is concluded that the molecule has substantially the same form in the orthorhombic and the monoclinic lattices, except for differences found between residues at the 3' end of the polynucleotides chain. A number of observations are made concerning hydrogen bonding interactions which may account for many of the residues conserved in all tRNA sequences. PMID:802512

  4. Plasticity and thermal recovery of thin copper wires in torsion

    NASA Astrophysics Data System (ADS)

    Dong, Dong; Dunstan, David J.; Bushby, Andrew J.

    2015-06-01

    Experiments in small-scale plasticity usually focus on small-sized samples. However, studying thin wires with lengths up to metres in torsion has the advantage of giving extremely high strain resolution and reversal of the loading direction. In this way, we explore the early stage of plasticity. Microstrain plastic deformation, dislocation creep and the Bauschinger effects are easily observed. The onset of irreversible deformation was observed and associated with a few dislocations in the largest grains throughout the wire. Easy plastic deformation on reversal of the loading direction was observed following this initial plastic deformation but not before.

  5. Advances in the genetics of primary torsion dystonia

    PubMed Central

    Valente, Enza Maria

    2010-01-01

    Knowledge about the genetics of primary torsion dystonia (PTD) has been progressing at a very slow pace compared with other movement disorders. For many years, only one causative gene was known, DYT1/TOR1A, yet the recent identification of a second PTD causative gene (DYT6/THAP1), the detection of subclinical alterations caused by mutations in PTD genes in some healthy non-penetrant individuals, and functional studies on TOR1A and THAP1 protein products have significantly improved mutation detection, genotype-phenotype correlates, and our understanding of the cellular mechanisms underlying the development of dystonia. PMID:20948792

  6. Confining Potential from Interacting Magnetic and Torsion Fields

    NASA Astrophysics Data System (ADS)

    Gaete, Patricio; Helaÿel-Neto, José A.

    Adopting the gauge-invariant but path-dependent variables formalism, we study the coupling of torsion fields with photons in the presence of an external background electromagnetic. We explicitly show that, in the case of a constant electric field strength expectation value, the static potential remains Coulombic, while in the case of a constant magnetic field strength expectation value a confining potential is obtained. This result displays a marked qualitative departure from the usual coupling of axionlike particles with photons in the presence of an external magnetic field.

  7. Deformation of olivine in torsion under hydrous conditions

    NASA Astrophysics Data System (ADS)

    Demouchy, Sylvie; Tommasi, Andréa; Barou, Fabrice; Mainprice, David; Cordier, Patrick

    2012-08-01

    We performed torsional deformation experiments on pre-hydrated fine-grained olivine aggregates using an innovative experimental assembly to investigate water weakening in mantle rocks at high shear strains. San Carlos olivine powder was cold-pressed and then hot-pressed under hydrous conditions, producing aggregates with average grain sizes of 7 or 15 μm. Deformation experiments were performed in a high-resolution gas-medium apparatus equipped with a torsional actuator, under a confining pressure of 300 MPa, a temperature of 1200 °C, and constant shear strain rates ranging from 8 × 10-5 to 1.4 × 10-4 s-1. Maximum shear stresses range from 150 to 195 MPa. These values are 30% lower relative to those determined in previous torsion experiments on dry, fined-grained dunites under similar conditions. Textures and microstructures of the starting and deformed specimens were characterized by scanning and transmission electron microscopy. All deformed aggregates exhibit a shape-preferred orientation marking a foliation and lineation, as well as a reduction in mean grain size from 15 μm down to 3-4 μm due to dynamic recrystallization. Olivine crystallographic fabrics developed rapidly (γ < 0.1), but their strength, characterized by the J-index, is low compared to naturally deformed peridotites or to polycrystalline olivine deformed at similar finite shear strains under dry conditions. The crystallographic fabrics are consistent with deformation by a dislocation accommodated creep mechanism with activation of multiple {0 k l}[1 0 0] systems, among which the (0 1 0)[1 0 0] slip system is dominant, and minor participation of the (0 1 0)[0 0 1] slip system. Transmission electron microscopy confirmed the occurrence of dislocations with [1 0 0] and [0 0 1] Burgers vectors in most grains. Analysis of unpolarized infrared spectra indicates that hydrogen concentration in the olivine lattice is below the saturation level of 18 ppm wt H2O, which is similar to those typically

  8. A biomechanical assessment of the coupling of torsion and tension in the human scapholunate ligament.

    PubMed

    Zdero, R; Olsen, M; Elfatori, S; Skrinskas, T; Schemitsch, E; Whyne, C; von Schroeder, H

    2008-08-01

    The mechanical behaviour of human scapholunate ligaments is not well described in the literature with regard to torsion. In this study, intact scapholunate specimens were mechanically tested in torsion to determine whether a simultaneous tensile load was generated. Human intact scapholunate specimens (n = 19) were harvested. The scaphoid and lunate bones were potted in square chambers using epoxy cement, while the interposing ligament remained exposed. Each specimen was mounted rigidly in a specially designed test jig and remained at a fixed axial length during all tests. Specimens were subjected to a torsional load regime that included cyclic preconditioning, ramp-up, stress relaxation, ramp-down, rest, and torsion to failure. Torque and axial tension were monitored simultaneously. The relationship between torsion and tension was determined. Graphs of torque versus tension were generated, from which outcome measures were extracted. Tests demonstrated a clear relationship between applied torsion and the resulting generation of tension for the ligament during ramp-up (torsion-to-tension ratio, 38.86 +/- 29.00 mm; linearity coefficient R2 = 0.89 +/- 0.15; n = 19), stress relaxation (torsion-to-tension ratio, 23.43 +/- 15.84 mm; R2 = 0.90 +/- 0.09; n = 16), and failure tests (torsion-to-tension ratio, 38.81 +/- 26.39mm; R2 = 0.77 +/- 0.20; n = 16). No statistically significant differences were detected between the torsion-to-tension ratios (p = 0.13) or between the linearity (R2) of the best-fit lines (p > 0.085). A strongly coupled linear relationship between torsion and tension for the scapholunate ligament was exhibited in all test phases. This may suggest interplay between these two parameters in the stabilization of the ligament during normal motion and for injury cascades. PMID:18935807

  9. Cross-axis adaptation of torsional components in the yaw-axis vestibulo-ocular reflex

    NASA Technical Reports Server (NTRS)

    Trillenberg, P.; Shelhamer, M.; Roberts, D. C.; Zee, D. S.

    2003-01-01

    The three pairs of semicircular canals within the labyrinth are not perfectly aligned with the pulling directions of the six extraocular muscles. Therefore, for a given head movement, the vestibulo-ocular reflex (VOR) depends upon central neural mechanisms that couple the canals to the muscles with the appropriate functional gains in order to generate a response that rotates the eye the correct amount and around the correct axis. A consequence of these neural connections is a cross-axis adaptive capability, which can be stimulated experimentally when head rotation is around one axis and visual motion about another. From this visual-vestibular conflict the brain infers that the slow-phase eye movement is rotating around the wrong axis. We explored the capability of human cross-axis adaptation, using a short-term training paradigm, to determine if torsional eye movements could be elicited by yaw (horizontal) head rotation (where torsion is normally inappropriate). We applied yaw sinusoidal head rotation (+/-10 degrees, 0.33 Hz) and measured eye movement responses in the dark, and before and after adaptation. The adaptation paradigm lasted 45-60 min, and consisted of the identical head motion, coupled with a moving visual scene that required one of several types of eye movements: (1) torsion alone (-Roll); (2) horizontal/torsional, head right/CW torsion (Yaw-Roll); (3) horizontal/torsional, head right/CCW torsion (Yaw+Roll); (4) horizontal, vertical, torsional combined (Yaw+Pitch-Roll); and (5) horizontal and vertical together (Yaw+Pitch). The largest and most significant changes in torsional amplitude occurred in the Yaw-Roll and Yaw+Roll conditions. We conclude that short-term, cross-axis adaptation of torsion is possible but constrained by the complexity of the adaptation task: smaller torsional components are produced if more than one cross-coupling component is required. In contrast, vertical cross-axis components can be easily trained to occur with yaw head

  10. Computed tomography for femoral and tibial torsion in children with clubfoot.

    PubMed

    Cuevas de Alba, C; Guille, J T; Bowen, J R; Harcke, H T

    1998-08-01

    Forty-seven children with 70 clubfeet had computed tomography studies performed to determine the degree of femoral, tibial, and total limb torsion in both lower limbs. The total limb torsion angle (angle between the axis of the femoral neck and the axis of the ankle), which describes the relationship between femoral and tibial torsion, was used to evaluate the whole rotational deformity of the lower limb. The children were between the ages of 2 and 10 years (mean, 5 years) at the time of the computed tomography study. The mean femoral torsion was 25 degrees in the limbs with a clubfoot and 23 degrees in the contralateral limbs of patients with a unilateral clubfoot. The mean tibial torsion was 25 degrees in the limbs with a clubfoot and 24 degrees in the contralateral limb of patients with a unilateral clubfoot. The authors observed decreases of anterior femoral torsion corresponding to increases in age, consistent with the observations made by other authors of studies of children without clubfoot. External tibial torsion increased with age, with similar values in limbs with and without clubfoot. Ten limbs (nine with clubfoot, one without clubfoot) had femoral torsion greater than the means plus one standard deviation and 12 limbs (eight with clubfoot, four without clubfoot) had tibial torsion less than the means minus one standard deviation. The authors found four limbs (all with clubfoot) in three patients with lower than the mean minus one standard deviation of the total limb torsion angle (intoeing). Overall, there was no appreciable difference in the amount of femoral or tibial torsion in limbs with and without a clubfoot. PMID:9728175

  11. Postoperative Change in Ocular Torsion in Intermittent Exotropia: Relationship with Postoperative Surgical Outcomes.

    PubMed

    Lee, Ju-Yeun; Hwang, Sungsoon; Oh, Shin Yeop; Park, Kyung-Ah; Oh, Sei Yeul

    2016-01-01

    The aim of this study was to determine whether objective ocular torsion in intermittent exotropia (IXT) changes after recession surgery, and to evaluate the relationship between change in ocular torsion and clinical parameters in IXT. Sixty patients between 3 and 14 years of age underwent lateral rectus (LR) recession for IXT. Digital fundus photographs were obtained from both eyes of each subject and the disc-foveal angle (ocular torsion) was calculated using image software. We compared the preoperative and postoperative amount of ocular torsion, and analyzed the correlation between the difference in ocular torsion (DOC) and clinical parameters including age, duration of strabismus, stereoacuity, amount of preoperative exodeviation, and mean dose response. We categorized the patients according to DOC value: positive DOC value as group 1, and negative DOC value as group 2. A correlation between ocular torsion dominance and fixation preference was also investigated using the Kappa test. The mean ocular torsion was 15.8 ± 4.6 degrees preoperatively and 13.7 ± 5.1 degrees postoperatively. Compared with preoperative values, the mean ocular torsion showed a significant decrease after LR recession (p<0.001), and a greater preoperative ocular torsion was significantly associated with the amount of DOC (r = 0.37, p<0.001). Degree of stereopsis, mean dose-response, and postoperative exodeviation were significantly different between group 1 (positive DOC) and group 2 (negative DOC) (p<0.001, 0.030, and 0.001 respectively). The Kappa test showed that there was a significant correlation between the dominance of ocular torsion and fixation preference (p = 0.020). Therefore, change in ocular torsion after LR recession can be a useful supplementary indicator for evaluating the degree of fusional control and for predicting postoperative surgical response in IXT. PMID:27622574

  12. Effects of Moderate Exercise on Relieving Mental Load of Elementary School Teachers

    PubMed Central

    Liu, Shing-Hong; Cheng, Da-Chuan; Wang, Jia-Jung; Lin, Tzu-Hsin; Chang, Kang-Ming

    2015-01-01

    Long-term endurance exercise could increase activity of parasympathetic nervous and decrease activity of sympathetic nervous at rest. However, previous studies all focused on the effect of endurance training on heart rate variability (HRV) for athletes or sedentary subjects. In Taiwan, elementary school teachers teaching and processing the children's and administrative problems always stand and walk. They will sit down only when they review and correct the students' home work. Thus, the goal of this study was to elucidate the beneficial effect of moderate intensity exercise on relieving mental load of elementary school teachers. There were 20 participants in the exercise group and another 20 participants in the nonexercise group. The exercising teachers performed 12 weeks of moderate intensity exercise training for an average of 30 minutes per day, 3 times per week. HRV was measured before and after the 4th, 6th, and 12th weeks. The time and frequency domain parameters of HRV all had significant increases between the beginning and after 12 weeks of training. However, the time and frequency domain parameters of HRV in the nonexercise group had significant decreases between the beginning and after 12 weeks of training. The long-term moderate exercises can relieve mental load of elementary school teachers. Moreover, age was the considerable factor affecting HRV in this study. PMID:25861352

  13. Effects of moderate exercise on relieving mental load of elementary school teachers.

    PubMed

    Liu, Shing-Hong; Cheng, Da-Chuan; Wang, Jia-Jung; Lin, Tzu-Hsin; Chang, Kang-Ming

    2015-01-01

    Long-term endurance exercise could increase activity of parasympathetic nervous and decrease activity of sympathetic nervous at rest. However, previous studies all focused on the effect of endurance training on heart rate variability (HRV) for athletes or sedentary subjects. In Taiwan, elementary school teachers teaching and processing the children's and administrative problems always stand and walk. They will sit down only when they review and correct the students' home work. Thus, the goal of this study was to elucidate the beneficial effect of moderate intensity exercise on relieving mental load of elementary school teachers. There were 20 participants in the exercise group and another 20 participants in the nonexercise group. The exercising teachers performed 12 weeks of moderate intensity exercise training for an average of 30 minutes per day, 3 times per week. HRV was measured before and after the 4th, 6th, and 12th weeks. The time and frequency domain parameters of HRV all had significant increases between the beginning and after 12 weeks of training. However, the time and frequency domain parameters of HRV in the nonexercise group had significant decreases between the beginning and after 12 weeks of training. The long-term moderate exercises can relieve mental load of elementary school teachers. Moreover, age was the considerable factor affecting HRV in this study. PMID:25861352

  14. Hypertension, Increased Aldosterone Secretion and Low Plasma Renin Activity Relieved by Dexamethasone

    PubMed Central

    Sutherland, D. J. A.; Ruse, J. L.; Laidlaw, J. C.

    1966-01-01

    A father and son are described with a condition characterized by benign hypertension, potassium deficiency, increased aldosterone secretion rate (ASR), raised plasma volume and suppressed plasma renin activity (PRA). There were intermittent elevations of urine 17-ketosteroids and 17-hydroxycorticoids (17-OHCS) but no increase in urine THS, normal circadian rhythm of plasma 17-OHCS, and normal urine 17-OHCS response to dexamethasone and intravenous ACTH. Plasma ACTH and corticosterone secretion were not elevated. Pregnanetriol excretion was normal but urine pregnanediol was increased. At operation on the father no adrenal tumour was found; the excised left adrenal weighed 7 g. and showed nodular cortical hyperplasia; juxtaglomerular cells showed only occasional granules. Following operation hypertension persisted and ASR was half the preoperative value. All abnormalities in father and son were relieved by dexamethasone (DM) 2 mg. daily. The condition recurred following cessation of DM but was relieved by a second course of treatment. No such response to DM was seen in a normal subject or in a patient with Conn's syndrome. For a number of reasons it is suggested that patients with hypertension, increased ASR and low PRA be given a trial of dexamethasone treatment before undergoing adrenal surgery. ImagesFig. 14 PMID:4288576

  15. A torsional completion of gravity for Dirac matter fields and its applications to neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Fabbri, Luca; Vignolo, Stefano

    2016-01-01

    In this paper, we consider the torsional completion of gravitation for an underlying background filled with Dirac fields, applying it to the problem of neutrino oscillations: we discuss the effects of the induced torsional interactions as corrections to the neutrino oscillations mechanism.

  16. Nonspecificity of the rim sign in the scintigraphic diagnosis of missed testicular torsion

    SciTech Connect

    Vieras, F.; Kuhn, C.R.

    1983-02-01

    Causes of a hyperemic peritesticular rim on dynamic and static scintigrams are reviewed. Of 6 patients exhibiting such a pattern, 3 had missed testicular torsion; the other 3 had tumor, trauma, or inflamation. The authors conclude that a hyperemic peritesticular rim is a nonspecific finding reflecting underlying pathophysiological changes and is not pathognomonic of missed torsion.

  17. Nonspecificity of the rim sign in the scintigraphic diagnosis of missed testicular torsion

    SciTech Connect

    Vieras, F.; Kuhn, C.R.

    1983-02-01

    Causes of a hyperemic peritesticular rim on dynamic and static scintigrams are reviewed. Of 6 patients exhibiting such a pattern, 3 had missed testicular torsion; the other 3 had tumor, trauma, or inflammation. The authors conclude that a hyperemic peritesticular rim is a nonspecific finding reflecting underlying pathophysiological changes and is not pathognomonic of missed torsion.

  18. Flap/Lag/Torsion Dynamics of a Uniform, Cantilever Rotor Blade in Hover

    NASA Technical Reports Server (NTRS)

    Johnson, W.

    1977-01-01

    The dynamic stability of the flap/lag/torsion motion of a uniform, cantilever rotor blade in hover is calculated. The influence of blade collective pitch, lag frequency, torsional flexibility, structural coupling, and precone angle on the stability is examined. Good agreement is found with the results of an independent analytical investigation.

  19. Highly Accurate Beam Torsion Solutions Using the p-Version Finite Element Method

    NASA Technical Reports Server (NTRS)

    Smith, James P.

    1996-01-01

    A new treatment of the classical beam torsion boundary value problem is applied. Using the p-version finite element method with shape functions based on Legendre polynomials, torsion solutions for generic cross-sections comprised of isotropic materials are developed. Element shape functions for quadrilateral and triangular elements are discussed, and numerical examples are provided.

  20. Effective Torsion and Spring Constants in a Hybrid Translational-Rotational Oscillator

    ERIC Educational Resources Information Center

    Nakhoda, Zein; Taylor, Ken

    2011-01-01

    A torsion oscillator is a vibrating system that experiences a restoring torque given by [tau] = -[kappa][theta] when it experiences a rotational displacement [theta] from its equilibrium position. The torsion constant [kappa] (kappa) is analogous to the spring constant "k" for the traditional translational oscillator (for which the restoring force…

  1. Relationship between head orientation and torsional eye movements in goldfish during linear acceleration

    NASA Astrophysics Data System (ADS)

    Takabayashi, A.; Ohmura, T.; Mori, S.

    We analyzed torsional eye movements of normal goldfish during sinusoidal linear acceleration, altering the orientation of the fish on the linear accelerator in the yaw plane over a range of 90 degrees and in the pitch plane up to 30 degrees. We video-recorded changes of torsional eye movements associated with a body rotation in the yaw and pitch plane and analyzed them frame by frame. In normal fish, we observed clear torsional eye movements for stimuli of 0.1G linear accelerations along the body axis in the horizontal position. Torsion occurred in the opposite direction of resultant force produced by linear acceleration and gravity. Though the amplitude of these compensatory responses increased with increasing magnitude of acceleration up to 0.5 G, the torsion angle did not fully compensate the angle calculated from gravity and linear acceleration. Furthermore, the torsion angle decreased as the longitudinal body axis deviated from the direction of linear acceleration. For the body axis perpendicular to the direction of acceleration, torsional eye movement was still observed. When we tilted the fish in the pitch plane, compensatory eye torsion occurred. The response amplitude to acceleration decreased for both head-up and head-down up to 30 degrees. These results suggested the existence of specific connections between the otolith organ and ocular muscles.

  2. Study of the HVDC-torsional interactions through digital dynamic simulation

    SciTech Connect

    Padiyar, K.R.; Kothari, A.G.

    1988-01-01

    This paper presents the detailed dynamic digital simulation for the study of phenomenon of torsional interaction between HVDC-Turbine generator shaft dynamics using the novel converter model. The system model includes detailed representation of the synchronous generator and the shaft dynamics, the ac and dc network transients. The results of a case study indicate the various factors that influence the torsional interaction.

  3. The experimental determination of the torsional barrier and shape for disilane.

    PubMed

    Moazzen-Ahmadi, N; Horneman, V-M

    2006-05-21

    The torsional spectrum of disilane was recorded for the first time under high-pressure-pathlength conditions and at a spectral resolution of 0.007 cm(-1) using a Bruker IFS-120 HR Fourier transform spectrometer. The spectrum shows six distinct Q branches. The most prominent Q branch is near 130 cm(-1) which is a blend of four components of the torsional fundamental. Of the remaining five, four were assigned to the first torsional hot band (v(4)=2<--1) and one to the second torsional hot band (v(4)=3<--2). Over 350 transitions were identified. An analysis of the torsional fundamental, the first torsional hot band, and the lower state combination differences from frequencies of the vibrational bands nu(9) and nu(9)+nu(4)-nu(4) was made to characterize the torsion-rotation Hamiltonian in the ground vibrational state. The barrier height, barrier shape, and the rotational constant about the Si-Si bond were determined to be 404.344(83) cm(-1), 2.255(65) cm(-1), and 43208(28) MHz, respectively. Comparison of simulated and the experimental spectra yielded (mu||-mu(perpendicular))/mu(perpendicular)= -4(1) for the torsional dipole moments. This ratio compares well with -3.39(6) for ethane. A comparison of molecular parameters obtained here is made with those for methyl silane and ethane. PMID:16729816

  4. The experimental determination of the torsional barrier and shape for disilane

    NASA Astrophysics Data System (ADS)

    Moazzen-Ahmadi, N.; Horneman, V.-M.

    2006-05-01

    The torsional spectrum of disilane was recorded for the first time under high-pressure-pathlength conditions and at a spectral resolution of 0.007cm-1 using a Bruker IFS-120 HR Fourier transform spectrometer. The spectrum shows six distinct Q branches. The most prominent Q branch is near 130cm-1 which is a blend of four components of the torsional fundamental. Of the remaining five, four were assigned to the first torsional hot band (v4=2←1) and one to the second torsional hot band (v4=3←2). Over 350 transitions were identified. An analysis of the torsional fundamental, the first torsional hot band, and the lower state combination differences from frequencies of the vibrational bands ν9 and ν9+ν4-ν4 was made to characterize the torsion-rotation Hamiltonian in the ground vibrational state. The barrier height, barrier shape, and the rotational constant about the Si-Si bond were determined to be 404.344(83)cm-1, 2.255(65)cm-1, and 43208(28)MHz, respectively. Comparison of simulated and the experimental spectra yielded (μ‖-μ⊥)/μ⊥=-4(1) for the torsional dipole moments. This ratio compares well with -3.39(6) for ethane. A comparison of molecular parameters obtained here is made with those for methyl silane and ethane.

  5. Emergent and nonemergent nonbowel torsion: spectrum of imaging and clinical findings.

    PubMed

    Lubner, Meghan G; Simard, Marissa L; Peterson, Christine M; Bhalla, Sanjeev; Pickhardt, Perry J; Menias, Christine O

    2013-01-01

    Although bowel torsion is more commonly described in the medical literature, torsion can affect various organs within the chest, abdomen, and pelvis, including the testes, ovaries, gallbladder, spleen, heart, and pulmonary lobes. A structural abnormality such as a mass (a "lead point") that promotes twisting around a vascular pedicle often predisposes an organ or other anatomic structure to torsion. Radiologists play a central role in detecting torsion, identifying the anatomy involved, and triaging patients for either emergent surgical intervention, which may be critical for organ salvage, or conservative management. Imaging findings that are suggestive or indicative of emergent torsion include an ectopic location and enlargement or edema of part or all of an organ, decreased blood flow at color Doppler ultrasonography, and a twisted vascular pedicle. Blood flow to an organ is quickly compromised by the constriction of vessels within the twisted pedicle, and ischemia may result; a delay in diagnosis and surgical treatment can lead to complications such as infarction, hemorrhagic necrosis, and abscess. By contrast, torsion of mobile fatty structures such as testicular appendages, epiploic appendages, omental fat, and pericardial fat pads, although it may produce pain mimicking that in an emergent condition, requires only conservative management. Imaging features of this nonemergent condition include a fatty mass, which is usually located alongside the colon when torsion involves the omentum or an epiploic appendage, with associated inflammatory stranding and tenderness at palpation. The radiologist should be familiar with these manifestations of nonemergent torsion to prevent unnecessary surgical intervention. PMID:23322835

  6. The effect of DNA supercoiling on nucleosome structure and stability

    NASA Astrophysics Data System (ADS)

    Elbel, Tabea; Langowski, Jörg

    2015-02-01

    Nucleosomes have to open to allow access to DNA in transcription, replication, and DNA damage repair. Changes in DNA torsional strain (e.g. during transcription elongation) influence the accessibility of nucleosomal DNA. Here we investigated the effect of DNA supercoiling-induced torsional strain on nucleosome structure and stability by scanning force microscopy (SFM) and fluorescence correlation spectroscopy (FCS). Nucleosomes were reconstituted onto 2.7 kb DNA plasmids with varying superhelical densities. The SFM results show a clear dependence of the amount of DNA wrapped around the nucleosome core on the strength and type of supercoiling. Negative supercoiling led to smaller nucleosome opening angles as compared to relaxed or positively supercoiled DNA. FCS experiments show that nucleosomes reconstituted on negatively superhelical DNA are more resistant to salt-induced destabilization, as seen by reduced H2A-H2B dimer eviction from the nucleosome. Our results show that changes in DNA topology, e.g. during transcription elongation, affect the accessibility of nucleosomal DNA.

  7. Quantum gravity, torsion, parity violation, and all that

    SciTech Connect

    Freidel, Laurent; Minic, Djordje; Takeuchi, Tatsu

    2005-11-15

    We discuss the issue of parity violation in quantum gravity. In particular, we study the coupling of fermionic degrees of freedom in the presence of torsion and the physical meaning of the Immirzi parameter from the viewpoint of effective field theory. We derive the low-energy effective Lagrangian which turns out to involve two parameters: one measuring the nonminimal coupling of fermions in the presence of torsion, the other being the Immirzi parameter. In the case of nonminimal coupling the effective Lagrangian contains an axial-vector interaction leading to parity violation. Alternatively, in the case of minimal coupling there is no parity violation and the effective Lagrangian contains only the usual axial-axial interaction. In this situation the real values of the Immirzi parameter are not at all constrained. On the other hand, purely imaginary values of the Immirzi parameter lead to violations of unitarity for the case of nonminimal coupling. Finally, the effective Lagrangian blows up for the positive and negative unit imaginary values of the Immirzi parameter.

  8. Matter-antimatter asymmetry and dark matter from torsion

    SciTech Connect

    Poplawski, Nikodem J.

    2011-04-15

    We propose a simple scenario which explains the observed matter-antimatter imbalance and the origin of dark matter in the Universe. We use the Einstein-Cartan-Sciama-Kibble theory of gravity which naturally extends general relativity to include the intrinsic spin of matter. Spacetime torsion produced by spin generates, in the classical Dirac equation, the Hehl-Datta term which is cubic in spinor fields. We show that under a charge-conjugation transformation this term changes sign relative to the mass term. A classical Dirac spinor and its charge conjugate therefore satisfy different field equations. Fermions in the presence of torsion have higher energy levels than antifermions, which leads to their decay asymmetry. Such a difference is significant only at extremely high densities that existed in the very early Universe. We propose that this difference caused a mechanism, according to which heavy fermions existing in such a Universe and carrying the baryon number decayed mostly to normal matter, whereas their antiparticles decayed mostly to hidden antimatter which forms dark matter. The conserved total baryon number of the Universe remained zero.

  9. S-duality in 3D gravity with torsion

    SciTech Connect

    Mielke, Eckehard W. . E-mail: ekke@xanum.uam.mx; Maggiolo, Ali A. Rincon

    2007-02-15

    The deformation of the connection in three spacetime dimensions by the kinematically equivalent coframe is shown to induce a duality between the (Lorentz-) rotational and translational field momenta, for which the coupling to the deformation parameter is inverted. This new kind of strong/weak duality, pertinent to 3D, is instrumental for studying exact solutions of the 3D Poincare gauge field equations and the particle content of propagating modes on a background of constant curvature. For a topological Chern-Simons model of gravity, the propagating modes 'living' on an Anti-de Sitter (AdS) background correspond to real massive particles. Yang-Mills type generalizations and new cubic Lagrangians are found and completely classified in 3D. AdS or black hole type solutions with constant axial torsion emerge, also for these higher-order Lagrangians with new 'exotic' torsion-curvature couplings. Their pattern complies with our S-duality, with new repercussions for the field redefinition of the metric in 3D quantum gravity and the cosmological constant problem.

  10. Simple torsion test for shear moduli determination of orthotropic composites

    NASA Technical Reports Server (NTRS)

    Sumsion, H. T.; Rajapakse, Y. D. S.

    1978-01-01

    The shear moduli G13 and G23 for two different composites (AS/3501 and T300/5209) of uniaxial and cross-ply fiber orientations were determined by torsion testing of flat specimens of rectangular cross section. Torsion tests were run under controlled angle of twist in an electro-hydraulic servo-controlled test system. Both laser and potentiometer methods of measuring the angle of twist were used. The in-plane shear modulus was calculated with a formula for transversally isotropic materials and a formula for orthotropic materials, while the out-of-plane shear modulus was calculated from the orthotropic material formula. Neither the uniaxial nor the angle-ply composite materials studied were transversely isotropic. The degree of anisotropy for the angle-ply materials was several times greater than that of the uniaxial composites. For specimens of uniaxial fiber orientation, the in-plane shear moduli could be calculated to a good approximation by using the isotropic formula and test machine deflection data.

  11. Effective protein conformational sampling based on predicted torsion angles.

    PubMed

    Yang, Yuedong; Zhou, Yaoqi

    2016-04-30

    Protein structure prediction is a long-standing problem in molecular biology. Due to lack of an accurate energy function, it is often difficult to know whether the sampling algorithm or the energy function is the most important factor for failure of locating near-native conformations of proteins. This article examines the size dependence of sampling effectiveness by using a perfect "energy function": the root-mean-squared distance from the target native structure. Using protein targets up to 460 residues from critical assessment of structure prediction techniques (CASP11, 2014), we show that the accuracy of near native structures sampled is relatively independent of protein sizes but strongly depends on the errors of predicted torsion angles. Even with 40% out-of-range angle prediction, 2 Å or less near-native conformation can be sampled. The result supports that the poor energy function is one of the bottlenecks of structure prediction and predicted torsion angles are useful for overcoming the bottleneck by restricting the sampling space in the absence of a perfect energy function. © 2015 Wiley Periodicals, Inc. PMID:26696379

  12. Architecture of torsional gyroscope having robust sense mode

    NASA Astrophysics Data System (ADS)

    Jain, Ankush; Sharma, Hitesh Kumar; Gopal, Ram

    2015-10-01

    An architecture of a torsional gyroscope having robust sense mode is reported. The robustness is achieved by utilizing dynamic amplification of torsional oscillations in the sense oscillator. The frequency response of the sense oscillator, which essentially is a 2-degree-of-freedom (DOF) one, has two resonance peaks and a flat region between the peaks, where the amplitude is less sensitive to ambient damping resulting in the robust sense mode. The frequency response of the 1-DOF drive oscillator has one resonance peak, which is designed to fall within the flat region of the sense amplitude. This helps in reducing the effects of change in the geometry and material properties of the device, induced by inevitable fabrication imperfections, on the device performance. The device is modeled by deriving the equations for electrostatic moment, moments of inertia, and spring constants. The design concepts of antiresonance and zero-phase frequency, along with analytical expressions for resonance frequencies and 3-dB bandwidth are also presented. The design is then realized using an SU-8 based ultraviolet-lithographie, galvanoformung, abformung (UV-LIGA) process having 8-μm thick Ni-Fe as the key structural layer. A characterization technique is developed to extract the frequency response of the fabricated device.

  13. Torsion, magnetic monopoles and Faraday's law via a variational principle

    NASA Astrophysics Data System (ADS)

    Mannheim, Philip D.

    2015-05-01

    Even though Faraday's Law is a dynamical law that describes how changing E and B fields influence each other, by introducing a vector potential Aμ according to Fμν = ∂νAν - ∂νAμ Faraday's Law is satisfied kinematically, with the relation (-g)-1/2ɛμνστ ∇νFστ = 0 holding on every path in a variational procedure or path integral. In a space with torsion Qαβγ the axial vector Sμ = (-g)1/2ɛμαβγQαβγ serves as a chiral analog of Aμ, and via variation with respect to Sμ one can derive Faraday's Law dynamically as a stationarity condition. With Sμ serving as an axial potential one is able to introduce magnetic monopoles without Sμ needing to be singular or have a non-trivial topology. Our analysis permits torsion and magnetic monopoles to be intrinsically Grassmann, which could explain why they have never been detected. Our procedure permits us to both construct a Weyl geometry in which Aμ is metricated and then convert it into a standard Riemannian geometry.

  14. Determination of transverse shear strength through torsion testing

    SciTech Connect

    Marcucelli, K.T.; Fish, J.C.

    1997-12-31

    The in-plane characterization of composite materials is, in general, well understood and widely utilized throughout the aerospace industry. However, the use of composites in structural elements such as fuselage frames and rotorcraft flexbeams place large out-of-plane or through-the-thickness stresses for which there is little data. Efforts to determine the interlaminar shear strength of laminated composites have been hampered due to the nonlinear behavior of test specimens and the limitations of current analysis tools. An inexpensive rectangular torsion test specimen was designed to determine the interlaminar shear strength, s{sub 23}, of composite materials. Six different layups were fabricated of AS4/2220-3 carbon/epoxy unidirectional tape and tested in pure torsion. All of the specimens failed abruptly with well-defined shear cracks and exhibited linear load-deflection behavior. A quasi-three-dimensional (Q-3-D) finite element analysis was conducted on each of the specimen configurations to determine the interlaminar shear stress at failure. From this analysis, s{sub 23} was found to be 107 MPa for this material.

  15. A MEMS torsion magnetic sensor with reflective blazed grating integration

    NASA Astrophysics Data System (ADS)

    Long, Liang; Zhong, Shaolong

    2016-07-01

    A novel magnetic sensor based on a permanent magnet and blazed grating is presented in this paper. The magnetic field is detected by measuring the diffracted wavelength of the blazed grating which is changed by the torsion motion of a torsion sensitive micro-electromechanical system (MEMS) structure with a permanent magnet attached. A V-shape grating structure is obtained by wet etching on a (1 0 0) SOI substrate. When the magnet is magnetized in different directions, the in-plane or out-of-plane magnetic field is detected by a sensor. The MEMS magnetic sensor with a permanent magnet is fabricated after analytical design and bulk micromachining processes. The magnetic-sensing capability of the sensor is tested by fiber-optic detection system. The result shows the sensitivities of the in-plane and out-of-plane magnetic fields are 3.6 pm μT‑1 and 5.7 pm μT‑1, respectively. Due to utilization of the permanent magnet and fiber-optic detection, the sensor shows excellent capability of covering the high-resolution detection of low-frequency signals. In addition, the sensitive direction of the magnetic sensor can be easily switched by varying the magnetized direction of the permanent magnet, which offers a simple way to achieve tri-axis magnetic sensor application.

  16. Spinning optical resonator sensor for torsional vibrational applications measurements

    NASA Astrophysics Data System (ADS)

    Ali, Amir R.; Gatherer, Andrew; Ibrahim, Mariam S.

    2016-03-01

    Spinning spherical resonators in the torsional vibrational applications could cause a shift in its whispering gallery mode (WGM). The centripetal force acting on the spinning micro sphere resonator will leads to these WGM shifts. An analysis and experiment were carried out in this paper to investigate and demonstrate this effect using different polymeric resonators. In this experiment, centripetal force exerted by the DC-Motor on the sphere induces an elastic deformation of the resonator. This in turn induces a shift in the whispering gallery modes of the sphere resonator. Materials used for the sphere are polydimethylsiloxane (PDMS 60:1 where 60 parts base silicon elastomer to 1 part polymer curing agent by volume) with shear modulus (G≍1kPa), (PDMS 10:1) with shear modulus (G≍300kPa), polymethylmethacrylate (PMMA, G≍2.6×109GPa) and silica (G≍3×1010 GPa). The sphere size was kept constant with 1mm in diameter for all above materials. The optical modes of the sphere exit using a tapered single mode optical fiber that is coupled to a distributed feedback laser. The transmission spectrum through the fiber is monitored to detect WGM shifts. The results showed the resonators with smaller shear modulus G experience larger WGM shift due to the larger mechanical deformation induced by the applied external centripetal force. Also, the results show that angular velocity sensors used in the torsional vibrational applications could be designed using this principle.

  17. Response of Robust Torsion Balances to Teleseismic Events

    NASA Astrophysics Data System (ADS)

    Madziwa-Nussinov, T. G.; Cowsik, R.; Wagoner, K.; Wiens, D. A.; Wysession, M. E.

    2009-12-01

    We have built a prototype of a robust rotational seismometer [1] based on the concept that torsion balances act as good filters to rotational seismic oscillations at frequencies above their natural frequency of torsional oscillations. We have operated it in spatial and temporal coincidence with a translational seismometer and have recorded several teleseismic events. This has allowed us to calibrate the response of the robust instrument and has given us confidence that the instrument we have developed has the requisite sensitivity for rotational seismology [2] in the field. We also discuss our plans for making the instrument user-friendly and our efforts to develop a highly sensitive instrument. [1] R. Cowsik, T. Madziwa-Nussinov, K. Wagoner, D. Wiens, and M. Wysession (2009) Bulletin of the Seismological Society of America 99, 1181-1189. [2] Lee H.K., M. Celebi, M.I. Todorovska and M. Diggles (2007) (eds.), Rotational Seismology and Engineering - On- line Proceedings for the First InternationalWorkship U.S. Geological Survey Open-File Report - 2007-1144 version 2.0.

  18. Matter-antimatter asymmetry and dark matter from torsion

    NASA Astrophysics Data System (ADS)

    Popławski, Nikodem J.

    2011-04-01

    We propose a simple scenario which explains the observed matter-antimatter imbalance and the origin of dark matter in the Universe. We use the Einstein-Cartan-Sciama-Kibble theory of gravity which naturally extends general relativity to include the intrinsic spin of matter. Spacetime torsion produced by spin generates, in the classical Dirac equation, the Hehl-Datta term which is cubic in spinor fields. We show that under a charge-conjugation transformation this term changes sign relative to the mass term. A classical Dirac spinor and its charge conjugate therefore satisfy different field equations. Fermions in the presence of torsion have higher energy levels than antifermions, which leads to their decay asymmetry. Such a difference is significant only at extremely high densities that existed in the very early Universe. We propose that this difference caused a mechanism, according to which heavy fermions existing in such a Universe and carrying the baryon number decayed mostly to normal matter, whereas their antiparticles decayed mostly to hidden antimatter which forms dark matter. The conserved total baryon number of the Universe remained zero.

  19. Rheology of deformed Carrara marble: Insights from torsion experiments

    NASA Astrophysics Data System (ADS)

    Bruijn, R. H. C.; Delle Piane, C.; de Raadt, W. S.

    2012-04-01

    Rock deformation experiments are essential for understanding lithosphere dynamics, strain localization processes and deformation mechanisms in polymineral aggregates, as they provide rheological parameters and record fabric development of rock-forming minerals, aiding the geological interpretation of naturally deformed rocks. Carrara marble received significant attention in the rock deformation community due to its homogeneous fabric and low impurities content, making it a laboratory standard. When the torsion actuator was developed for the Paterson-type gas-medium apparatus, it became possible to perform high strain experiments and reach true steady state flow conditions in Carrara marble. At the center of these ground breakings developments stood Luigi Burlini and his students. Their work showed for the first time, the importance of fabric development on steady state flow stress in response to high strain deformation and recrystallization. In the last years of Luigi's life, he and his students took rock deformation studies to a different direction by investigating the effect of initial strain and quantifying the coupling between fabric and flow stress. We present here an overview of the four types of torsion experiment that were performed on Carrara marble with varied pre-existing strain. Earlier torsion experiments on homogeneous Carrara marble provided the framework in which these newer experiments were evaluated. In type I experiments samples were subjected to a torsion deformation leading to a maximum shear strain of 1 to 5, immediately followed by a reversed straining of equal magnitude. In type II and III experiments, a composite sample consisting of a segment of undeformed and one (type II) or two (type III) segment(s) of previously twisted Carrara marble, were deformed. In type IV experiments, a cylindrical segment of dynamically recrystallized Carrara marble was annealed 727 °C for up to five hours at to recover the original grain size without removing

  20. HIGH-LATITUDE SOLAR TORSIONAL OSCILLATIONS DURING PHASES OF CHANGING MAGNETIC CYCLE AMPLITUDE

    SciTech Connect

    Rempel, M.

    2012-05-01

    Torsional oscillations are variations of the solar differential rotation that are strongly linked to the magnetic cycle of the Sun. Helioseismic inversions have revealed significant differences in the high-latitude branch of torsional oscillations between cycle 23 and cycle 24. Here we employ a non-kinematic flux-transport dynamo model that has been used previously to study torsional oscillations and simulate the response of the high-latitude branch to a change in the amplitude of the magnetic cycle. It is found that a reduction of the cycle amplitude leads to an increase in the amplitude of differential rotation that is mostly visible as a drop in the high-latitude rotation rate. Depending on the amplitude of this adjustment the high-latitude torsional oscillation signal can become temporarily hidden due to the unknown changing mean rotation rate that is required to properly define the torsional oscillation signal.

  1. Measurement of tibial torsion and thigh-foot angle using goniometry and computed tomography.

    PubMed

    Stuberg, W; Temme, J; Kaplan, P; Clarke, A; Fuchs, R

    1991-11-01

    Three therapists measured tibiofibular torsion and thigh-foot angle (TFA) goniometrically in 17 normal subjects, aged three to 24 years. Tibiofibular torsion was also measured using computed tomography (CT). Differences between testers for the goniometric measures were analyzed using a nonparametric analysis of variance. Wilcoxon's rank sum test was used to determine differences between goniometric and CT measures for tibiofibular torsion. No significant difference for goniometric measures was found between testers for tibiofibular torsion or TFA. A significant difference averaging 5 degrees between goniometric and CT torsion measures was found between testers. Although a significant difference was found between the two measurement methods, the degree of difference may not represent a significant clinical difference, as a range at 5 degrees is commonly reported as the margin of error for goniometric measurements. PMID:1934735

  2. TEMPERATURE GRADIENTS IN THE SOLAR ATMOSPHERE AND THE ORIGIN OF CUTOFF FREQUENCY FOR TORSIONAL TUBE WAVES

    SciTech Connect

    Routh, S.; Musielak, Z. E.; Hammer, R. E-mail: zmusielak@uta.ed

    2010-02-01

    Fundamental modes supported by a thin magnetic flux tube embedded in the solar atmosphere are typically classified as longitudinal, transverse, and torsional waves. If the tube is isothermal, then the propagation of longitudinal and transverse tube waves is restricted to frequencies that are higher than the corresponding global cutoff frequency for each wave. However, no such global cutoff frequency exists for torsional tube waves, which means that a thin and isothermal flux tube supports torsional tube waves of any frequency. In this paper, we consider a thin and non-isothermal magnetic flux tube and demonstrate that temperature gradients inside this tube are responsible for the origin of a cutoff frequency for torsional tube waves. The cutoff frequency is used to determine conditions for the wave propagation in the solar atmosphere, and the obtained results are compared to the recent observational data that support the existence of torsional tube waves in the Sun.

  3. Field verification of lateral-torsional coupling effects on rotor instabilities in centrifugal compressors

    NASA Technical Reports Server (NTRS)

    Wachel, J. C.; Szenasi, F. R.

    1980-01-01

    Lateral and torsional vibration data obtained on a centrifugal compressor train which had shaft instabilities and gear failures is examined. The field data verifies that the stability of centrifugal compressors can be adversely affected by coincidence of torsional natural frequencies with lateral instability frequencies. The data also indicates that excitation energy from gear boxes can reduce stability margins if energy is transmitted either laterally or torsionally to the compressors. The lateral and torsional coupling mechanisms of shaft systems is discussed. The coupling mechanisms in a large industrial compressor train are documented and the potential effect on rotor stability is demonstrated. Guidelines are set forth to eliminate these potential problems by minimizing the interaction of torsional and lateral responses and their effect on rotor stability.

  4. Rotation-torsion analysis of the Si2H6 infrared fundamental ν, perturbed by excited torsional levels of the vibrational ground state

    NASA Astrophysics Data System (ADS)

    Lattanzi, F.; di Lauro, C.; Horneman, V.-M.

    The lowest infrared active perpendicular fundamental ν9 of disilane has been analysed on a Fourier transform spectrum between 320 and 430 cm-1, at the spectral resolution of 0.0012 cm-1. The rotation-torsion structure of this band is affected by x,y Coriolis interactions with excited torsional levels of the vibrational ground state, correlating with components of 3ν4 and 4ν4 in the high barrier limit. The interaction of ν9 and 4ν4, forbidden in the D3d symmetry limit, is allowed between components of E torsional symmetry under the G36(EM) extended molecular group, because of the large amplitude of the internal rotation motion. We could determine the values of the main vibration-rotation-torsion parameters of ν9, interaction parameters, and the vibrational wavenumbers of the four torsional components of 3ν4 and of the E3d component of 4ν4. The intrinsic torsional splitting of ν9 is found to be smaller than in the ground vibrational state by 0.0066 cm-1, in good agreement with our theoretical predictions. The possibility of observing the effects of D3d-forbidden interactions in the spectra of ethane-like molecules is also discussed.

  5. Oxidative Stress during Ovarian Torsion in Pediatric and Adolescent Patients: Changing The Perspective of The Disease

    PubMed Central

    Laganà, Antonio Simone; Sofo, Vincenza; Salmeri, Francesca Maria; Palmara, Vittorio Italo; Triolo, Onofrio; Terzić, Milan Milosav; Patrelli, Tito Silvio; Lukanovic, Adolf; Bokal, Eda Vrtcnik; Santoro, Giuseppe

    2016-01-01

    Among the different causes of gynecological acute pelvic pain, ovarian torsion represents a surgical emergency. It is a rare case in the pediatric/adolescent aged group that must be included in the differential diagnosis of any girl with abdominal pain or pelvic/abdominal mass. Current recommendations suggest that laparoscopic detorsion should be performed in order to preserve the integrity of the ovaries and fertility, although oophoropexy may be considered in case of severe necrosis. Nevertheless, maintaining the circulation of the ovary after detorsion deteriorates the tissue injury and leads to a pathologic process called ischaemia/reperfusion (I/R) injury, which is characterized by oxidative stress. During the detorsion process, an excess amount of molecular oxygen is supplied to the tissues, and reactive species of oxygen (ROS) such as superoxide radical (O2-), hydrogen peroxide (H2O2), hydroxyl radical (OH•), as well as reactive nitrogen species (RNS) are produced in excess. ROS, RNS and their toxic products cause DNA damage and lipid peroxidation in the cellular and mitochondrial membranes, leading to cell death. In spite of attention on this topic, currently there is no shared and clear evidence about the use of anti-inflammatory and antioxidant agents to prevent I/R damage after laparoscopic ovarian detorsion. Considering this element, future research should aim to develop shared protocols for the clinical use (route of application, dosage and time of application) of antioxidants after laparoscopic management of this condition. PMID:26985329

  6. Oxidative Stress during Ovarian Torsion in Pediatric and Adolescent Patients: Changing The Perspective of The Disease.

    PubMed

    Laganà, Antonio Simone; Sofo, Vincenza; Salmeri, Francesca Maria; Palmara, Vittorio Italo; Triolo, Onofrio; Terzić, Milan Milosav; Patrelli, Tito Silvio; Lukanovic, Adolf; Bokal, Eda Vrtcnik; Santoro, Giuseppe

    2016-01-01

    Among the different causes of gynecological acute pelvic pain, ovarian torsion represents a surgical emergency. It is a rare case in the pediatric/adolescent aged group that must be included in the differential diagnosis of any girl with abdominal pain or pelvic/abdominal mass. Current recommendations suggest that laparoscopic detorsion should be performed in order to preserve the integrity of the ovaries and fertility, although oophoropexy may be considered in case of severe necrosis. Nevertheless, maintaining the circulation of the ovary after detorsion deteriorates the tissue injury and leads to a pathologic process called ischaemia/reperfusion (I/R) injury, which is characterized by oxidative stress. During the detorsion process, an excess amount of molecular oxygen is supplied to the tissues, and reactive species of oxygen (ROS) such as superoxide radical (O2 (-)), hydrogen peroxide (H2O2), hydroxyl radical (OH•), as well as reactive nitrogen species (RNS) are produced in excess. ROS, RNS and their toxic products cause DNA damage and lipid peroxidation in the cellular and mitochondrial membranes, leading to cell death. In spite of attention on this topic, currently there is no shared and clear evidence about the use of anti-inflammatory and antioxidant agents to prevent I/R damage after laparoscopic ovarian detorsion. Considering this element, future research should aim to develop shared protocols for the clinical use (route of application, dosage and time of application) of antioxidants after laparoscopic management of this condition. PMID:26985329

  7. Condensation of circular DNA

    NASA Astrophysics Data System (ADS)

    Starostin, E. L.

    2013-04-01

    A simple model of a circularly closed double-stranded DNA in a poor solvent is considered as an example of a semi-flexible polymer with self-attraction. To find the ground states, the conformational energy is computed as a sum of the bending and torsional elastic components and the effective self-attraction energy. The model includes a relative orientation or sequence dependence of the effective attraction forces between different pieces of the polymer chain. Two series of conformations are analysed: a multicovered circle (a toroid) and a multifold two-headed racquet. The results are presented as a diagram of state. It is suggested that the stability of particular conformations may be controlled by proper adjustment of the primary structure. Application of the model to other semi-flexible polymers is considered.

  8. Counterintuitive DNA Sequence Dependence in Supercoiling-Induced DNA Melting

    PubMed Central

    Vlijm, Rifka; v.d. Torre, Jaco; Dekker, Cees

    2015-01-01

    The metabolism of DNA in cells relies on the balance between hybridized double-stranded DNA (dsDNA) and local de-hybridized regions of ssDNA that provide access to binding proteins. Traditional melting experiments, in which short pieces of dsDNA are heated up until the point of melting into ssDNA, have determined that AT-rich sequences have a lower binding energy than GC-rich sequences. In cells, however, the double-stranded backbone of DNA is destabilized by negative supercoiling, and not by temperature. To investigate what the effect of GC content is on DNA melting induced by negative supercoiling, we studied DNA molecules with a GC content ranging from 38% to 77%, using single-molecule magnetic tweezer measurements in which the length of a single DNA molecule is measured as a function of applied stretching force and supercoiling density. At low force (<0.5pN), supercoiling results into twisting of the dsDNA backbone and loop formation (plectonemes), without inducing any DNA melting. This process was not influenced by the DNA sequence. When negative supercoiling is introduced at increasing force, local melting of DNA is introduced. We measured for the different DNA molecules a characteristic force Fchar, at which negative supercoiling induces local melting of the dsDNA. Surprisingly, GC-rich sequences melt at lower forces than AT-rich sequences: Fchar = 0.56pN for 77% GC but 0.73pN for 38% GC. An explanation for this counterintuitive effect is provided by the realization that supercoiling densities of a few percent only induce melting of a few percent of the base pairs. As a consequence, denaturation bubbles occur in local AT-rich regions and the sequence-dependent effect arises from an increased DNA bending/torsional energy associated with the plectonemes. This new insight indicates that an increased GC-content adjacent to AT-rich DNA regions will enhance local opening of the double-stranded DNA helix. PMID:26513573

  9. Humor Therapy: Relieving Chronic Pain and Enhancing Happiness for Older Adults

    PubMed Central

    Tse, Mimi M. Y.; Lo, Anna P. K.; Cheng, Tracy L. Y.; Chan, Eva K. K.; Chan, Annie H. Y.; Chung, Helena S. W.

    2010-01-01

    The present study examined the effectiveness of a humor therapy program in relieving chronic pain, enhancing happiness and life satisfaction, and reducing loneliness among older persons with chronic pain. It was a quasiexperimental pretest-posttest controlled design. Older persons in a nursing home were invited to join an 8-week humor therapy program (experimental group), while those in another nursing home were treated as a control group and were not offered the program. There were 36 older people in the experimental group and 34 in the control group. Upon completion of the humor therapy program, there were significant decreases in pain and perception of loneliness, and significant increases in happiness and life satisfaction for the experimental group, but not for the control group. The use of humor therapy appears to be an effective nonpharmacological intervention. Nurses and other healthcare professionals could incorporate humor in caring for their patients. PMID:21151506

  10. Benign coital headache relieved by partner’s pregnancies with implications for future treatment

    PubMed Central

    Dexter, Selwyn

    2010-01-01

    This is a case of a male patient with a 27 year history of severe benign coital headache and associated symptoms. His condition was spontaneously relieved in the first trimester of his partner’s pregnancy. This relief continued through the remainder of the pregnancy term, returning only after the birth of their child. The timing of the condition’s relief and return of symptoms suggested progesterone was an intrinsic factor in this. Post-pregnancy the patient was able to prevent his attacks by taking oral norethisterone 5 mg. While writing this case the patient’s partner became pregnant once more, resulting again in spontaneous relief of the patient’s syndrome. PMID:22315637

  11. Efficient near-field energy transfer and relieved Casimir stiction between sub-wavelength gratings

    NASA Astrophysics Data System (ADS)

    Liu, Xianglei; Zhao, Bo; Zhang, Zhuomin

    2015-03-01

    The promising applications of near-field heat transfer in thermophotovoltaic devices, thermal imaging, thermal rectifiers, and local thermal management have motivated the search for nanostructures capable of supporting higher efficiency or greater heat flux than simple planar substances. In this work, efficient and delocalized radiative heat transfer between two aligned 1D sub-wavelength gratings is demonstrated based on the scattering theory using the rigorous coupled-wave analysis (RCWA). It is shown that the heat flux can be greatly enhanced and the accurate prediction may differ significantly from that of the geometry-based Derjaguin's proximity approximation (PA). The underlying mechanism is attributed to the excitation of hyperbolic modes that increase the energy transmission by supporting propagation of waves with large parallel wavevectors and. Besides efficient energy transport, the performance is robust, insensitive to the relative lateral shift. In addition, the Casimir stiction considering both quantum and thermal fluctuations is found to be relieved compared with bulks.

  12. [A girl with dyslexia suspected to have Irlen syndrome, completely relieved by wearing tinted lenses].

    PubMed

    Kusano, Yusuke; Awaya, Tomonari; Saito, Keiko; Yoshida, Takeshi; Ide, Minako; Kato, Takeo; Heike, Toshio; Kato, Toshihiro

    2015-11-01

    Irlen syndrome is a proposed perceptual processing disorder characterized by visual distortions while reading. Patients with this syndrome may experience light sensitivity, visual stress, and other related problems such as dyslexia. Tinted lenses and colored overlays have been designed to help individuals with the symptoms of Irlen syndrome. However, there is still debate over the effectiveness of these interventions and whether this syndrome actually exists. In this report, we describe a case involving an 8-year-old girl with dyslexia who experienced severe visual hypersensitivity and whose symptoms completely resolved after wearing tinted lenses. While it is possible that she experienced a psychogenic visual disturbance that was relieved because of the placebo effect, the clinical course of her symptoms matched the findings previously described by Irlen. The patient was unable to read without tinted lenses. With tinted lenses, she could read at the appropriate age level, suggesting that her difficulty was due to a problem in optical information processing. The concepts underlying Irlen syndrome are vaguely defined, and several groups insist that the visual stress associated with this syndrome might be responsible for dyslexia as well as other disorders. These ambiguous criteria may be responsible for the criticism over the validity of this condition. Although this was only an anecdotal case, our patient exhibited the core functional deficit described in Irlen syndrome and showed a dramatic improvement with tinted lenses; therefore, this case may facilitate investigations into the mechanism underlying Irlen syndrome, if it actually exists. Although further studies are required to confirm the validity of this syndrome and the treatment approach, Irlen syndrome should be recognized as a disorder since its symptoms can be easily relieved by wearing tinted lenses or color filters. PMID:26717646

  13. Torsionally Excited Dimethyl Ether in the Laboratory and in Space

    NASA Astrophysics Data System (ADS)

    Endres, C. P.; Müller, H. S. P.; Lewen, F.; Giesen, T. F.; Schlemmer, S.; Drouin, B. J.; Bisschop, S.; Groner, P.

    2010-06-01

    Dimethyl ether (DME) is highly abundant in hot cores and numerous transitions within the vibrational ground state have been detected in various interstellar line surveys of sources such as Orion KL. As a nearly prolate asymmetric top with two internal rotors, it shows a complex spectrum with low lying torsional modes. The energy levels of the two lowest torsional states (v11, and v15) lie only 200 and 240 cm-1 above the ground state (barrier height ≈ 915 cm-1), and are thus sufficiently populated in these interstellar sources to exhibit transitions in line surveys due to high excitation temperatures in hot cores. So far, the lack of sufficiently accurate predictions for the two lowest excited torsional states prevented their identification in astronomical spectra. Therefore, we analyzed spectra, which have been recorded within the context of the investigations of the ground state. In total, more than 9500 transitions have been assigned covering the frequency range from 38 up to 1670 GHz. The enlarged splitting of each rotational level into four substates (AA, EE, AE, EA) compared to its size in the ground state and a large number of perturbed transitions hampered not only the line assignment but also the astrophysical modelling. However, the inclusion of interaction terms between both excited states in the model of an effective Hamiltonian for a symmetric two-top rotor, allowed us to model both excited states within a global fit, and also to accurately determine the energy difference between both states. Frequency predictions have been calculated based on this analysis and have been used to unambiguously assign numerous rotational transitions within these excited states in the astronomical line survey of the hot core region G327.3-0.6. P. Schilke, T.D. Groesbeck et al., Astrophys.J.Suppl.Ser., 108,(1997) 301-337 P. Schilke, D.J. Benford, T.R. Hunter et al., Astrophys.J.Suppl.Ser., 132,(2001) 281-364. P. Groner, S. Albert, E. Herbst, and F.C. De Lucia, Astrophys

  14. Propagation and reflection of diffusionless torsional waves in a sphere

    NASA Astrophysics Data System (ADS)

    Maffei, S.; Jackson, A.

    2016-03-01

    We consider an inviscid and perfectly conducting fluid sphere in rapid rotation and permeated by a background magnetic field. Such a system admits normal modes in the form of torsional oscillations, namely azimuthal motions of cylinders coaxial with the rotation axis. We analyse this system for a particular background magnetic field that provides a new closed form normal mode solution. We derive Wentzel-Kramers-Brillouin-Jeffreys (WKBJ) approximations to the normal modes, and focus particularly on the reflections that take place on the rotation axis and at the equator. We propose a procedure to calculate the reflection coefficients and we discuss the analogy of our findings with well-known seismological results. Our analytical results are tested against numerical calculations and show good agreement.

  15. A study of a proposed modified torsional agility metric

    NASA Technical Reports Server (NTRS)

    Valasek, John; Eggold, David P.; Downing, David R.

    1991-01-01

    A new candidate lateral agility metric, the modified torsional agility parameter, is proposed and tested through generic, nonlinear, non-real-time flight simulation programs of the F-18 and F-5A. The metric is aimed at quantifying high subsonic loaded roll capabilities which might be useful in modern air combat. The metric is considered to be straightforward for testing and measuring based on nonreal-time unmanned flight simulation. The metric is found to be sensitive to pilot input errors of less than full lateral stick to capture bank angle, when tested using unmanned flight simulations. It is suggested that, for redesigned configurations of both aircraft with improved lateral agility, the major benefit would be provided by fast and highly effective rudders, and a high level of pitch, roll, and yaw damping at moderate to high normal load factor levels.

  16. Collective effects of torsion in FtsZ filaments

    NASA Astrophysics Data System (ADS)

    González de Prado Salas, Pablo; Tarazona, Pedro

    2016-04-01

    Recent evidence points to the presence of torsion in FtsZ bonds. In addition, experiments with FtsZ mutants on surfaces resulted in new aggregates that cannot be explained by older models for FtsZ dynamics. We use an interaction model for FtsZ derived from molecular dynamics simulations and expand a fine-grained lattice model used to describe FtsZ aggregates on a surface. This new model includes different anchoring angles for the monomers and allows bond twist, two ingredients that oppose each other resulting in a more dynamic and interesting system. We study the role and importance of these conflicting elements and how the aggregates are characterized by the different interaction parameters.

  17. Sertoliform Endometrioid Tumor of Ovary Presenting as Torsion

    PubMed Central

    Pai, Prathiksha; Jadhav, Meena N; Patil, Rashmi K; Kittur, Shreekant K

    2016-01-01

    Sertoliform endometrioid carcinoma of the ovary (SEC) is an uncommon variant that bears histologic similarity to sertoli and sertoli-leydig cell tumors. We report an interesting case of SEC in a 55-year-old female with a left ovarian mass with torsion. Histology revealed an SEC, featuring foci of typical endometrioid carcinoma, and areas composed of uniform, small, hollow tubules lined by columnar cells with apical cytoplasm. Tumor cells were strongly immunoreactive for EMA and cytokeratin but negative for inhibin; thus, confirming the diagnosis of SEC ovary. Recognition of this tumor is important as it is a well-differentiated, low-grade malignancy that displays good prognosis when confined to the ovary. PMID:27365921

  18. Test of spatial isotropy using a cryogenic torsion pendulum

    NASA Technical Reports Server (NTRS)

    Phillips, Peter R.

    1987-01-01

    Motion of the earth through the cosmic neutrino background, or through certain kinds of vacuum states, produces a term of the form g(sigma) x v in the energy of an electron. To search for such a term, a cryogenic torsion pendulum carrying a transversely polarized magnet was used. Superconducting shields reduced magnetic torques. A sigma x v term would produce a sinusoidal oscillation of the pendulum with a period of one sidereal day. Such an oscillation was not detected, and a new limit of 8.5 x 10 to the -18th eV has been set for the splitting of the spin states of an electron at rest on the earth.

  19. Fiber optic stress-independent helical torsion sensor.

    PubMed

    Fernandes, Luís A; Grenier, Jason R; Aitchison, J Stewart; Herman, Peter R

    2015-02-15

    Femtosecond laser-fabricated waveguides have been formed into helical paths throughout the cladding of single-mode optical fibers to demonstrate a strain-independent fiber torsion sensor. A comparison between a Bragg grating sensor and a Mach-Zehnder based on helical waveguides (HWs) showed a much weaker twist sensitivity of 1.5 pm/(rad/m) for the grating in contrast with a value of 261 pm/(rad/m) for the interferometer. The HW geometry provided an unambiguous determination of the rotational direction of the twist while facilitating a convenient and efficient means for optical coupling into the single-mode core of the fiber. The flexible three-dimensional writing by the femtosecond laser fabrication method enabled the direct inscription of compact and robust optical cladding devices without the need for combining or splicing multiple-fiber segments. PMID:25680174

  20. Effect of Helium Elasticity on Torsional Oscillator Measurements

    NASA Astrophysics Data System (ADS)

    Maris, Humphrey J.; Balibar, Sebastien

    2011-01-01

    In 2004 Kim and Chan performed a torsional oscillator measurement of the rotational inertia of solid helium-4. They found frequency changes which were interpreted in terms of a non-classical rotational inertia, that is a partial superfluidity or "supersolidity" of solid helium-4. Since then there have been many further studies using various versions of this technique. One important question that arises in these experiments is the possible effect on the oscillator frequency of changes in the elasticity of the solid helium; this can produce a change in frequency that adds to any effect due to superfluidity. In this paper we give a general discussion of the effect of changes in elasticity on the oscillator frequency and consider how the magnitude of the effect is influenced by the oscillator design. Our results should help make it possible to discriminate between frequency changes due to changes in elasticity and changes due to supersolidity.

  1. Torsional vibration measurement of the viscosity of a metallic melt

    NASA Astrophysics Data System (ADS)

    Bel'tyukov, A. L.; Olyanina, N. V.; Lad'yanov, V. I.

    2016-02-01

    The liquid Co91B9 alloy is used as an example to study the influence of boundary conditions at the upper melt boundary on the results of viscosity measurements using torsional vibrations. Specific features related to film effects and wetting phenomena are shown to appear in the temperature dependence of logarithmic decrement. To exclude the influence of these effects and phenomena, viscosity measurements should be performed under the experimental conditions where the melt to be studied is in closed volume and the internal crucible walls are fully wetted. The temperature dependence of the kinematic viscosity of the Co91B9 melt that is obtained under such experimental conditions has a monotonic character.

  2. Sertoliform Endometrioid Tumor of Ovary Presenting as Torsion.

    PubMed

    Pai, Prathiksha; Jadhav, Meena N; Patil, Rashmi K; Kittur, Shreekant K

    2016-01-01

    Sertoliform endometrioid carcinoma of the ovary (SEC) is an uncommon variant that bears histologic similarity to sertoli and sertoli-leydig cell tumors. We report an interesting case of SEC in a 55-year-old female with a left ovarian mass with torsion. Histology revealed an SEC, featuring foci of typical endometrioid carcinoma, and areas composed of uniform, small, hollow tubules lined by columnar cells with apical cytoplasm. Tumor cells were strongly immunoreactive for EMA and cytokeratin but negative for inhibin; thus, confirming the diagnosis of SEC ovary. Recognition of this tumor is important as it is a well-differentiated, low-grade malignancy that displays good prognosis when confined to the ovary. PMID:27365921

  3. Bending-torsion flutter of a highly swept advanced turboprop

    NASA Technical Reports Server (NTRS)

    Mehmed, O.; Kaza, K. R. V.; Lubomski, J. F.; Kielb, R. E.

    1981-01-01

    Experimental and analytical results are presented for a bending-torsion flutter phenomena encountered during wind-tunnel testing of a ten-bladed, advanced, high-speed propeller (turboprop) model with thin airfoil sections, high blade sweep, low aspect ratio, high solidity and transonic tip speeds. Flutter occurred at free-stream Mach numbers of 0.6 and greater and when the relative tip Mach number (based on vector sum of axial and tangential velocities) reached a value of about one. The experiment also included two- and five-blade configurations. The data indicate that aerodynamic cascade effects have a strong destabilizing influence on the flutter boundary. The data was correlated with analytical results which include aerodynamic cascade effects and good agreement was found.

  4. Solid 4He probed by both torsional oscillator and ultrasound

    NASA Astrophysics Data System (ADS)

    Kojima, Harry; Iwasa, Izumi; Goodkind, John

    2013-03-01

    The interpretation of observed anomalous increases in the frequencies of torsional oscillators (TO) containing solid 4He confined in Vycor nanopores as evidence for emergence of a supersolid phase has been met recently by conflicting experiments. Yet questions remain on the origin of the observed TO anomalies in bulk solid 4He samples. To search for the origin, we are carrying out simultaneous measurements of 10 MHz longitudinal ultrasound and TOs (250 ~ 1100 Hz) on identical solid 4He samples. Temperature dependence of velocity and attenuation of ultrasound and that of amplitude and frequency of TO are measured. At the temperatures, where TO anomalies occur, anomalies in sound velocity and attenuation also appear. When solid 4He is doped with 20 ppm 3He, the tempeature of TO anomaly tracks that of ultrasound. Interpretation of these observations in terms of the motion of dislocation lines will be presented. Research supported by NSF.

  5. Torsional Stiffness Verification of an Adhesively Bonded Joint

    NASA Astrophysics Data System (ADS)

    Annicchiarico, A.; Caputo, F.; De Angelis, G.; Frascà, F.; Lamanna, G.

    2010-06-01

    In the present work numerical-experimental analysis for the characterization of a structural adhesive has been performed. The numerical analysis has been carried out through the finite element method by using, for the phases pre / post processing were used commercial programs while for the phase of numerical solution the Abaqus code was used. The experimental analyses were carried out at laboratories of C.R.F. S.C.p.A. by using of a standard quasi static testing machine. Later numerical analysis was performed comparing the torsional stiffness of a vehicle in which the welded connection between the pavilion and the flank has been substituted by bonded one. This comparison has allowed to demonstrate the ability of the bonded joint discussed to provide mechanical performances comparable with those of a welded joint widely used in the automotive industry.

  6. The predicted effect of aerodynamic detuning on coupled bending-torsion unstalled supersonic flutter

    NASA Technical Reports Server (NTRS)

    Hoyniak, D.; Fleeter, S.

    1986-01-01

    A mathematical model is developed to predict the enhanced coupled bending-torsion unstalled supersonic flutter stability due to alternate circumferential spacing aerodynamic detuning of a turbomachine rotor. The translational and torsional unsteady aerodynamic coefficients are developed in terms of influence coefficients, with the coupled bending-torsion stability analysis developed by considering the coupled equations of motion together with the unsteady aerodynamic loading. The effect of this aerodynamic detuning on coupled bending-torsion unstalled supersonic flutter as well as the verification of the modeling are then demonstrated by considering an unstable 12 bladed rotor, with Verdon's uniformly spaced Cascade B flow geometry as a baseline. However, with the elastic axis and center of gravity at 60 percent of the chord, this type of aerodynamic detuning has a minimal effect on stability. For both uniform and nonuniform circumferentially space rotors, a single degree of freedom torsion mode analysis was shown to be appropriate for values of the bending-torsion natural frequency ratio lower than 0.6 and higher 1.2. When the elastic axis and center of gravity are not coincident, the effect of detuning on cascade stability was found to be very sensitive to the location of the center of gravity with respect to the elastic axis. In addition, it was determined that when the center of gravity was forward of an elastic axis located at midchord, a single degree of freedom torsion model did not accurately predict cascade stability.

  7. The Impact Of Torsional Oscillations On The Solar Cycle: The Waldmeier-effect As An Outcome

    NASA Astrophysics Data System (ADS)

    Mahajan, Sushant S.; Nandy, Dibyendu; Dwivedi, Bhola N.; Antia, H. M.

    2016-05-01

    Temporal variations in the Sun’s internal velocity field with a periodicity of about 11 years have been observed in the last three decades. The period of these torsional oscillations and their latitudinal propagation roughly coincide with the period and equatorward propagation of sunspots which originate from a magnetohydrodynamic dynamo mechanism operating in the Sun’s interior. While the solar differential rotation plays an important role in this dynamo mechanism by inducting the toroidal component of magnetic field, the impact of torsional oscillations on the dynamo mechanism – and hence the solar cycle – is not well understood. Here, we include the observed torsional oscillations into a flux transport dynamo model of the solar cycle to inves- tigate their effect. Although the overall amplitude of the solar cycle does not change significantly on inclusion of torsional oscillations we find that all the characteristics of the Waldmeier effect inthe sunspot cycle are qualitatively reproduced by varying only the amplitude of torsional oscillations. The Waldmeier effect, first noted in 1935, includes the important characteristic that the amplitude of sunspot cycles is anti-correlated to their rise time; cycles with high initial rise rate tend to be stronger. This has implications for solar cycle predictions. Our result suggests that the Waldmeier effect is a plausible outcome of cycle-to-cycle modulation of torsional oscillations and provides a physical basis for sunspot cycle forecasts based on torsional oscillation observations.

  8. Snap loads and torsional oscillations of the original Tacoma Narrows Bridge

    NASA Astrophysics Data System (ADS)

    Plaut, R. H.

    2008-01-01

    In 1940, the original Tacoma Narrows Bridge was completed on June 10 and opened to traffic on July 1. On November 7, the deck collapsed. Before that day, significant vertical oscillations had occurred, but no torsion. The bridge as built was stable with respect to torsional motion under the winds of November 7 and previous winds with higher speeds. However, snap loads in the diagonal ties attached to the north midspan cable band helped to loosen the band, and the frictional resistance between the band and the north suspension cable passing through it was overcome. The cable began to slip through the band. For this new structural system, with longitudinal motion of the north cable, the wind speed was higher than the critical speed for torsional flutter, and torsional motion was initiated. Approximately 700 cycles of torsional oscillations occurred during the hour prior to the collapse. In the present study, the snap loads on the cable band are discussed first. Then a continuum model of the central span (deck, cables, and hangers) is formulated. The longitudinal motions of the cables are included, so that the slippage can be incorporated. Known information from the observed steady-state torsional motion is utilized with assumed forms of the vertical cable displacements, and the governing equations provide the horizontal cable displacements, the dynamic tensions in the cables, the vertical and torsional motions of the deck, and the resultant lift force and pitching moment (including damping) acting on the deck during its final hour.

  9. Coupled torsional and bending motions in s-cis methyl vinyl ether

    NASA Astrophysics Data System (ADS)

    Meyer, Rolf; Ha, Tae-Kyu; Oldani, Markus; Caminati, Walther

    1987-02-01

    New microwave measurements on s-cis methyl vinyl ether and a study of the interactions among skeletal and methyl torsions and COC bending are reported. Using pulsed microwave Fourier transform spectroscopy, the small methyl torsional A-E splitting (0.16 MHz) in the vibrational ground state has been resolved for the first time. Large splittings are observed in the first excited states of skeletal torsion and COC bending. Ab initio results on the torsional coupling, allowing for structural relaxation, are reported and used to specify, in part, a flexible model for the torsional and bending motions. The spectroscopic properties of this three-dimensional model sytem, as estimated from the results for the one-dimensional and two-dimensional subsystems, explain the relevant experimental data. The gearing type torsional interaction predicted ab initio is confirmed by this treatment. The adjusted potential function as well as the structural relaxations upon torsion suggest repulsive interaction between the methyl hydrogen atoms and the methylenic hydrogen atom next to the methyl group.

  10. Human ocular torsion during parabolic flights: an analysis with scleral search coil

    NASA Technical Reports Server (NTRS)

    Cheung, B. S.; Money, K.; Howard, I.; Kirienko, N.; Johnson, W.; Lackner, J.; Dizio, P.; Evanoff, J.

    1992-01-01

    Rotation of the eyes about the visual axis is known as ocular torsion. A lateral inclination (a "roll") of the head induces ocular torsion in the opposite direction, a response known as ocular counterrolling. For six subjects, we recorded the static (head still) and dynamic (head in oscillatory roll motion) ocular torsion in normal 1 g condition and also during the microgravity and hypergravity periods of parabolic flight, using the electromagnetic scleral search coil technique. With the head still, the direction and magnitude of torsion that occurred in response to microgravity and hypergravity differed substantially from one individual to another, but there was a significant difference in torsional magnitude between the microgravity and hypergravity periods, for all static head positions including the upright position. Under normal 1 g conditions, counterrolling compensated for about 16% of (voluntary) static head roll, while dynamic counterroll was much larger, up to 36% of head roll at 0.55 Hz. With increasing frequency of head oscillation between 0.33 Hz and 0.55 Hz, the gain of counterrolling increased and there was no change in the phase relationship. The gain of dynamic counterroll (in response to voluntary head rolling) was not significantly less in hypogravity, suggesting that on the ground at these frequencies the contribution of gravity and gravity receptors to this reflex is redundant: this reflex is probably driven by the semicircular canals. In some subjects, the torsional displacement in microgravity is accompanied by micro-torsional oscillatory motion.

  11. Instability of ocular torsion in zero gravity - Possible implications for space motion sickness

    NASA Technical Reports Server (NTRS)

    Diamond, Shirley G.; Markham, Charles H.; Money, Ken E.

    1990-01-01

    It is proposed that study of the eye torsion reflex and its behavior under novel gravitational states may possibly provide the basis for a long-sought test to predict space motion sickness (SMS). Measures of eye torsion such as ocular counterrolling and spontaneous eye torsion, were examined during hypo- and hypergravity in parabolic flight on the NASA KC-135 aircraft. Ten subjects, including two astronauts, one who had experienced SMS and one who had not, were ranked according to scores of torsional inability at 0 G and divided into two equal groups of high and low susceptibility to SMS. At 1.8 G the groups were significantly different in both the instability measure and the measure of torsional ability. No differences were detected in eye torsion in either 0 G or 1.8 G and none of the tests were significantly different in 1 G. Results suggest that tests of eye torsion on the KC-135 might differentiate those who would experience SMS from those who would not, although it is noted that this is not yet proven.

  12. Cumulative Axial and Torsional Fatigue: An Investigation of Load-Type Sequencing Effects

    NASA Technical Reports Server (NTRS)

    Kalluri, Sreeramesh; Bonacuse, Peter J.

    2000-01-01

    Cumulative fatigue behavior of a wrought cobalt-base superalloy, Haynes 188 was investigated at 538 C under various single-step sequences of axial and torsional loading conditions. Initially, fully-reversed, axial and torsional fatigue tests were conducted under strain control at 538 C on thin-walled tubular specimens to establish baseline fatigue life relationships. Subsequently, four sequences (axial/axial, torsional/torsional, axial/torsional, and torsional/axial) of two load-level fatigue tests were conducted to characterize both the load-order (high/low) and load-type sequencing effects. For the two load-level tests, summations of life fractions and the remaining fatigue lives at the second load-level were computed by the Miner's Linear Damage Rule (LDR) and a nonlinear Damage Curve Approach (DCA). In general, for all four cases predictions by LDR were unconservative. Predictions by the DCA were within a factor of two of the experimentally observed fatigue lives for a majority of the cumulative axial and torsional fatigue tests.

  13. Pathological torsional eye deviation during voluntary saccades: a violation of Listing's law.

    PubMed Central

    Helmchen, C; Glasauer, S; Büttner, U

    1997-01-01

    BACKGROUND: Under normal conditions, there are no torsional eye movements during voluntary saccades when the head is stationary (Listing's law). METHODS AND RESULTS: Using dual search coils for three dimensional eye movement recordings, a patient is reported who had direction specific rapid deviations of torsional eye position (up to 10.5 degrees) during voluntary saccades followed by a slow exponential torsional drift after the end of the saccade ("blip") towards the initial torsional eye position. In the absence of spontaneous nystagmus, this transient torsion means a violation of Listing's law for voluntary saccades and was associated with a lesion involving the cerebellar vermis, its deep nuclei, and the dorsolateral medulla. Amplitudes of the blip were larger for ipsilesional (hypermetric) than contralesional (hypometric) horizontal saccades. For comparison transient torsion during and after saccades was also examined in six normal subjects. Using the same in vivo calibration, there were no blips larger than 1.2 degrees in any of them. CONCLUSION: Transient torsion with large amplitudes can be clinically seen on bedside examination and might thus be a new clinical sign in the diagnosis of saccadic disorders. Images PMID:9069480

  14. FIR Synchrotron Spectroscopy of High Torsional Levels of CD_3OH: the Tau of Methanol

    NASA Astrophysics Data System (ADS)

    Lees, Ronald M.; Xu, Li-Hong; Billinghurst, Brant E.

    2015-06-01

    Sub-bands involving high torsional levels of the CD_3OH isotopologue of methanol have been analyzed in Fourier transform spectra recorded at the Far-Infrared beamline of the Canadian Light Source synchrotron in Saskatoon. Energy term values for A and E torsional species of the third excited torsional state, v_t = 3, are now almost complete up to rotational levels K = 15, and thirteen substates have so far been identified for v_t = 4. The spectra show interesting close groupings of high-v_t sub-bands related by Dennison's torsional symmetry label τ, rather than A and E, that can be understood in terms of a simple and universal free-rotor "spectral predictor" chart. Transitions between states on the same free rotor curve have torsional overlap matrix elements close to unity, so give rise to strong sub-bands providing radiative routes for rapid population transfer through the high torsional manifold. Where the energy curves for the v_t = 3 and 4 ground-state torsional levels pass through the excited vibrational states, strong resonances can occur and a number of anharmonic and Coriolis interactions have been detected through perturbations to the spectra and appearance of forbidden transitions due to strong mixing and intensity borrowing.

  15. Impact of intelligent phacoemulsification software on torsional phacoemulsification surgery

    PubMed Central

    Ugurbas, Silay Canturk; Caliskan, Sinan; Alpay, Atilla; Ugurbas, Suat Hayri

    2012-01-01

    Background The purpose of this study was to compare phacoemulsification energy parameters during torsional phacoemulsification with or without the use of intelligent phacoemulsification (IP) software. Methods One hundred and twenty-eight eyes with nuclear grades ranging from 1 to 5 were enrolled in this randomized prospective study. Operated eyes were divided into two groups, ie, those operated on using IP software (Group 1, n = 67) and those operated on without IP software (Group 2, n = 61). The two groups were compared in terms of ultrasound energy level, ultrasound energy time, aspiration time, and amount of fluid used during surgery. Results Operated eyes were further grouped according to soft (grade 1 and 2, n = 37), medium (grade 3, n = 46), and hard (grade 4 and 5, n = 31) nuclear densities. Both the study and the control groups were similar in distribution of nuclear density (P > 0.05). Cumulative dissipated energy was measured as 14.06 ± 9.92 in Group 1 and 14.22 ± 10.99 in Group 2 (P = 0.92). Total ultrasound time was 49 seconds in Group 1 and 52 seconds in Group 2 (P = 0.58). Although the torsional amplitude used was similar (P = 0.86) when IP was either on (71%) or off (68.4%), aspiration time was found to be 4 minutes 17 seconds in Group 1 (P = 0.86) and 5 minutes and 17 seconds in Group 2 (P = 0.007). Total fluid used was measured as 91 cc (P = 0.86) in Group 1 and 109 cc (P = 0.02) in Group 2. Conclusion The new IP software did not cause a difference in ultrasound energy levels. However, the new software was found to be advantageous in regards to fluid use and aspiration time. PMID:23055669

  16. Technology development for the LISA using the UF Torsion Pendulu

    NASA Astrophysics Data System (ADS)

    Conklin, John W.; Chilton, Andrew; Olatunde, Taiwo; Apple, Stephen; Ciani, Giacomo; Mueller, Guido

    2015-08-01

    Space-based gravitational wave observatories like LISA measure picometer changes in the distances between free falling test masses separated by millions of kilometers caused by gravitational waves. A test mass and its associated sensing, actuation, charge control and caging subsystems are referred to as a gravitational reference sensor (GRS). LISA will observe gravitational wave sources ranging from super-massive black hole mergers to compact galactic binaries in the millihertz region, and LISA science has consistently been ranked in the top two for future large space missions in the last two NASA astrophysics decadal reviews. With the 2015 launch of LISA Pathfinder (LPF) and the expected detection of gravitational waves by aLIGO and/or Pulsar Timing Arrays within in the next several years, this can arguably be called the decade of gravitational waves. Following a successful demonstration of the baseline LISA GRS by LPF, the measurement principle will be carried forward, but improvements in several GRS components are possible over the next ten years that will lead to cost savings and potential noise reductions. The UF LISA group has constructed the UF Torsion Pendulum to increase U.S. competency in this critical area and to have a facility where new technologies can be developed and evaluated. This experimental facility is based on the design of a similar facility at the University of Trento, and consists of a vacuum enclosed torsion pendulum that suspends mock-ups of the LISA test masses, surrounded by electrode housings. This presentation will describe this facility, focusing on its mechanical design, capacitive sensing and electrostatic actuation systems, and overall acceleration noise performance

  17. Old torsion Balance Observations - too old for modern Exploration?

    NASA Astrophysics Data System (ADS)

    Götze, H.-J.

    2003-04-01

    Gravity gradiometry is a new gravity measurement technology that could fundamentally change the game of subsurface modelling and enhance geological interpretations: at fully inertial stabilized platforms they provide observed components of the E&{uml;o}tv&{uml;o}s tensor for 3D interpretations in mining and oil exploration and other fields of pure and applied geophysics. Although gravity gradiometry was among the first geophysical methods used successfully in applied Geophysics (E&{uml;o}tv&{uml;o}s torsion balance), the technology fell from favour in the 1930s. From this time measurements, done by torsion balances (Drehwaagen), are presented here which were observed to detect salt domes in the Northwest German basin. The data were digitized from old copies, then reprocessed and recalculated to draw Bouguer anomaly maps. However, the second derivatives of the gravity potential provide also independent data which can be used to constrain forward modelling. 3D modelling of Vxz, Vyz and other components of the E&{uml;o}tv&{uml;o}s tensor provide better insight into the geometry of the salt dome structure than modelling of the Bouguer gravity field. In addition to this first example results from gravity data processing by applying curvature techniques and again 3D forward modelling of second derivatives of the potential of density domains in the uppermost crust in the area of the Dead Sea Transform (Jordan) is presented here. The 3D modelling is conducted by the program package IGMAS which supply possibilities to calculate potential, gravity, its components and the Eötvös tensor components. Based on results so far one can conclude that the knowledge of the "second derivatives of the potential" could fundamentally change the role of gravity field measurements in the process of underground investigations not only for resource exploration but for investigations along large faults systems.

  18. Torsional elasticity and energetics of F1-ATPase.

    PubMed

    Czub, Jacek; Grubmüller, Helmut

    2011-05-01

    F(o)F(1)-ATPase is a rotary motor protein synthesizing ATP from ADP driven by a cross-membrane proton gradient. The proton flow through the membrane-embedded F(o) generates the rotary torque that drives the rotation of the asymmetric shaft of F(1). Mechanical energy of the rotating shaft is used by the F(1) catalytic subunit to synthesize ATP. It was suggested that elastic power transmission with transient storage of energy in some compliant part of the shaft is required for the observed high turnover rate. We used atomistic simulations to study the spatial distribution and structural determinants of the F(1) torsional elasticity at the molecular level and to comprehensively characterize the elastic properties of F(1)-ATPase. Our fluctuation analysis revealed an unexpected heterogeneity of the F(1) shaft elasticity. Further, we found that the measured overall torsional moduli of the shaft arise from two distinct contributions, the intrinsic elasticity and the effective potential imposed on the shaft by the catalytic subunit. Separation of these two contributions provided a quantitative description of the coupling between the rotor and the catalytic subunit. This description enabled us to propose a minimal quantitative model of the F(1) energetics along the rotary degrees of freedom near the resting state observed in the crystal structures. As opposed to the usually employed models where the motor mechanical progression is described by a single angular variable, our multidimensional treatment incorporates the spatially inhomogeneous nature of the shaft and its interactions with the stator and offers new insight into the mechanoenzymatics of F(1)-ATPase. PMID:21502534

  19. Carbon nanotube torsional springs for regenerative braking systems

    NASA Astrophysics Data System (ADS)

    Liu, Sanwei; Martin, Corbin; Lashmore, David; Schauer, Mark; Livermore, Carol

    2015-10-01

    The modeling and demonstration of large stroke, high energy density and high power density torsional springs based on carbon nanotube (CNT) yarns is reported, as well as their application as energy-storing actuators for regenerative braking systems. An originally untwisted CNT yarn is cyclically loaded and unloaded in torsion, with the maximum rotation angle increasing incrementally until failure. The measured average extractable energy density values are 2.9 kJ kg-1  ±  1.2 kJ kg-1 and 3.4 kJ kg-1  ±  0.4 kJ kg-1 for 1-ply CNT yarns and 2-ply CNT yarns, respectively. Additionally, a regenerative braking system is demonstrated to capture the kinetic energy of a wheel and store it as elastic energy in twisted CNT yarns. When the yarn’s twist is released, the stored energy reaccelerates the wheel. The measured energy and mean power densities of the CNT yarns in the simple regenerative braking setup are on average 3.3 kJ kg-1 and 0.67 kW kg-1, respectively, with maximum measured values of up to 4.7 kJ kg-1 and 1.2 kW kg-1, respectively. A slightly lower energy density of up to 1.2 kJ kg-1 and a 0.29 kW kg-1 mean power density are measured for CNT yarns in a more complex setup that mimics a unidirectional rotating regenerative braking mechanism.

  20. Torsional elasticity and energetics of F1-ATPase

    PubMed Central

    Czub, Jacek; Grubmüller, Helmut

    2011-01-01

    FoF1-ATPase is a rotary motor protein synthesizing ATP from ADP driven by a cross-membrane proton gradient. The proton flow through the membrane-embedded Fo generates the rotary torque that drives the rotation of the asymmetric shaft of F1. Mechanical energy of the rotating shaft is used by the F1 catalytic subunit to synthesize ATP. It was suggested that elastic power transmission with transient storage of energy in some compliant part of the shaft is required for the observed high turnover rate. We used atomistic simulations to study the spatial distribution and structural determinants of the F1 torsional elasticity at the molecular level and to comprehensively characterize the elastic properties of F1-ATPase. Our fluctuation analysis revealed an unexpected heterogeneity of the F1 shaft elasticity. Further, we found that the measured overall torsional moduli of the shaft arise from two distinct contributions, the intrinsic elasticity and the effective potential imposed on the shaft by the catalytic subunit. Separation of these two contributions provided a quantitative description of the coupling between the rotor and the catalytic subunit. This description enabled us to propose a minimal quantitative model of the F1 energetics along the rotary degrees of freedom near the resting state observed in the crystal structures. As opposed to the usually employed models where the motor mechanical progression is described by a single angular variable, our multidimensional treatment incorporates the spatially inhomogeneous nature of the shaft and its interactions with the stator and offers new insight into the mechanoenzymatics of F1-ATPase. PMID:21502534

  1. Global axial-torsional dynamics during rotary drilling

    NASA Astrophysics Data System (ADS)

    Gupta, Sunit K.; Wahi, Pankaj

    2016-08-01

    We have studied the global dynamics of the bottom hole assembly (BHA) during rotary drilling with a lumped parameter axial-torsional model for the drill-string and a linear cutting force model. Our approach accounts for bit-bounce and stick-slip along with the regenerative effect and is independent of the drill-string and the bit-rock interaction model. Regenerative axial dynamics due to variable depth of cut is incorporated through a functional description of the cut surface profile instead of a delay differential equation with a state-dependent delay. The evolution of the cut surface is governed by a nonlinear partial differential equation (PDE) which is coupled with the ordinary differential equations (ODEs) governing the longitudinal and angular dynamics of the BHA. The boundary condition for the PDE captures multiple regeneration in the event of bit-bounce. Interruption in the torsional dynamics is included by considering separate evolution equations for the various states during the stick period. Finite-dimensional approximation for our coupled PDE-ODE model has been obtained and validated by comparing our results against existing results. Bifurcation analysis of our system reveals a supercritical Hopf bifurcation leading to periodic vibrations without bit-bounce and stick-slip which is followed by solutions involving bit-bounce or stick-slip depending on the operating parameters. Further inroads into the unstable regime leads to a variety of complex behavior including co-existence of periodic and chaotic solutions involving both bit-bounce and stick-slip.

  2. Dynamic fragmentation of ferroelectric ceramics using the torsional Kolsky bar

    SciTech Connect

    Costin, L S; Grady, D E

    1983-10-01

    This paper studied the dynamic loading and subsequent fragmentation of four different load zirconate titanate (95/5 PZT) ferroelectric ceramics using a torsional Kolsky bar apparatus. Solid cylinders of the four materials were loaded in torsion at shear strain rates in the range 10/sup 2/ to 10/sup 3/s/sup -1/. Using the strain gage recordings of the incident, reflected and transmitted pulses, the energy required to fragment the specimen was determined for each test. In addition, the fragments resulting from each test were collected and analyzed by various technciques to determine their mass and size distributions. Results show some differences in particle distributions between the different batches of material. However, there is a more significant and consistent difference between the dynamic strength (as measured by the maximum shear stress) and the fragment mass distributions of the virgin material and the pressure depoled material, despite the fact that no differences were detected in the energy of fragmentation. Using earlier analytical results which relate the local kinetic energy of a potential fragment to the surface energy required to create that fragment, a relationship between the distribution of fragments from a test and material properties was derived. Results of tests on PZT as well as other materials such as oil shale, graphite, uranium dioxide and glass indicate a good correlation between the fragment distribution parameter, n, and material properties as predicted by the theory. Finally, the results are analyzed to determine the potential effects of internal stresses on the dynamic strength of the material and its fragmentation characteristics.

  3. Discrete Torsion, (Anti) de Sitter D4-Brane and Tunneling

    NASA Astrophysics Data System (ADS)

    Singh, Abhishek K.; Pandey, P. K.; Singh, Sunita; Kar, Supriya

    2014-06-01

    We obtain quantum geometries on a vacuum created pair of a (DDbar)3-brane, at a Big Bang singularity, by a local two form on a D4-brane. In fact our analysis is provoked by an established phenomenon leading to a pair creation by a gauge field at a black hole horizon by Stephen Hawking in 1975. Importantly, the five dimensional microscopic black holes are described by an effective non-perturbative curvature underlying a discrete torsion in a second order formalism. In the case for a non-propagating torsion, the effective curvature reduces to Riemannian, which in a low energy limit may describe Einstein vacuum in the formalism. In particular, our analysis suggests that a non-trivial space begin with a hot de Sitter brane-Universe underlying a nucleation of a vacuum pair of (DDbar)-instanton at a Big Bang. A pair of instanton nucleats a D-particle which in turn combines with an anti D-particle to describe a D-string and so on. The nucleation of a pair of higher dimensional pair of brane/anti-brane from a lower dimensional pair may be viewed via an expansion of the brane-Universe upon time. It is in conformity with the conjecture of a branes within a brane presumably in presence of the non-zero modes of two form. Interestingly, we perform a thermal analysis underlying various emergent quantum de Sitter vacua on a D4-brane and argue for the plausible tunneling geometries underlying a thermal equilibrium. It is argued that a de Sitter Schwarzschild undergoes quantum tunneling to an AdS-brane Schwarzschild via Nariai and de Sitter topological black hole.

  4. Lorentz violation from torsion trace and non-minimal coupling in radio galactic dynamos

    NASA Astrophysics Data System (ADS)

    Garcia de Andrade, L. C.

    2011-12-01

    Earlier Kostelecky et al. [A. Kostelecky, N. Russell, and J. Tasson, Phys Rev Lett 100, 111102 (2008).PRLTAO0031-900710.1103/PhysRevLett.100.111102] have obtained torsion bounds from Lorentz violation, where torsion components are taken from the axial part of torsion. In this brief report it is shown that more stringent bounds may be obtained by using nearly minimal magnetogenesis torsion trace instead of the minimal coupling between photons and axial torsion used by Kostelecky and his group. Just for comparison, in Kostelecky et al., the most stringent limit is estimated to be 10-31GeV while here one obtains 10-33GeV. This estimate is obtained by constraining the torsion to galactic astronomy data. From the point of view of magnetogenesis, an interesting physical consequence is that dynamo action is obtained when the torsion trace background is negative, while the magnetic field energy decays when torsion is positive. Polarization of radio-galaxies can be used to obtain an even more stringent limit of T˜1.7×10-46GeV to Lorentz violation. Using WMAP, Kostelecky and Mewes [A. Kostelecky and M. Mewes, Astrophys. J. 689, L1 (2008)ASJOAB0004-637X10.1086/595815] have found limits of the order of 10-43GeV. These results are obtained by making use of flat torsion modes [L. Garcia de Andrade, Phys Lett B 696, 1 (2011)], but may easily be extended to Riemann-Cartan spacetime.

  5. Spin precession of slow neutrons in Einstein-Cartan gravity with torsion, chameleon, and magnetic field

    NASA Astrophysics Data System (ADS)

    Ivanov, A. N.; Wellenzohn, M.

    2016-02-01

    We analyze a spin precession of slow neutrons in the Einstein-Cartan gravity with torsion, chameleon and magnetic field. For the derivation of the Heisenberg equation of motion of the neutron spin we use the effective low-energy potential, derived by Ivanov and Wellenzohn [Phys. Rev. D 92, 125004 (2015)] for slow neutrons, coupled to gravitational, chameleon, and torsion fields to order 1 /m , where m is the neutron mass. In addition to these low-energy interactions we switch on the interaction of slow neutrons with a magnetic field. We show that to linear order approximation with respect to gravitational, chameleon, and torsion fields the Dirac Hamilton operator for fermions (neutrons), moving in spacetimes created by rotating coordinate systems, contains the anti-Hermitian operators of torsion-fermion (neutron) interactions, caused by torsion scalar and tensor space-space-time and time-space-space degrees of freedom. Such anti-Hermitian operators violate C P and T invariance. In the low-energy approximation the C P and T violating torsion-fermion (neutron) interactions appear only to order O (1 /m ). One may assume that in the rotating Universe and galaxies the obtained anti-Hermitian torsion-fermion interactions might be an origin of (i) violation of C P and T invariance in the Universe and (ii) of baryon asymmetry. We show that anti-Hermitian torsion-fermion interactions of relativistic fermions, violating C P and T invariance, (i) cannot be removed by nonunitary transformations of the Dirac fermion wave functions and (ii) are conformal invariant. According to general requirements of conformal invariance of massive particle theories in gravitational fields [see R. H. Dicke, Phys. Rev. 125, 2163 (1962) and A. J. Silenko, Phys. Rev. D 91, 065012 (2015)], conformal invariance of anti-Hermitian torsion-fermion interactions is valid only if the fermion mass is changed by a conformal factor.

  6. Determining the shear fracture properties of HIP joints of reduced-activation ferritic/martensitic steel by a torsion test

    NASA Astrophysics Data System (ADS)

    Nozawa, Takashi; Noh, Sanghoon; Tanigawa, Hiroyasu

    2012-08-01

    Hot isostatic pressing (HIP) is a key technology used to fabricate a first wall with cooling channels for the fusion blanket system utilizing a reduced-activation ferritic/martensitic steel. To qualify the HIPped components, small specimen test techniques are beneficial not only to evaluate the thin-wall cooling channels containing the HIP joint but also to use in neutron irradiation studies. This study aims to develop the torsion test method with special emphasis on providing a reasonable and comprehensive method to determine interfacial shear properties of HIP joints during the torsional fracture process. Torsion test results identified that the torsion process shows yield of the base metal followed by non-elastic deformation due to work hardening of the base metal. By considering this work hardening issue, we propose a reasonable and realistic solution to determine the torsional yield shear stress and the ultimate torsional shear strength of the HIPped interface. Finally, a representative torsion fracture process was identified.

  7. An Assessment of Cumulative Axial and Torsional Fatigue in a Cobalt-Base Superalloy

    NASA Technical Reports Server (NTRS)

    Kalluri, Sreeramesh; Bonacuse, Peter J.

    2010-01-01

    Cumulative fatigue under axial and torsional loading conditions can include both load-order (higMow and low/high) as well as load-type sequence (axial/torsional and torsional/axial) effects. Previously reported experimental studies on a cobalt-base superalloy, Haynes 188 at 538 C, addressed these effects. These studies characterized the cumulative axial and torsional fatigue behavior under high amplitude followed by low amplitude (Kalluri, S. and Bonacuse, P. J., "Cumulative Axial and Torsional Fatigue: An Investigation of Load-Type Sequance Effects," in Multiaxial Fatigue and Deformation: Testing and Prediction, ASTM STP 1387, S. Kalluri, and P. J. Bonacuse, Eds., American Society for Testing and Materials, West Conshohocken, PA, 2000, pp. 281-301) and low amplitude followed by high amplitude (Bonacuse, P. and Kalluri, S. "Sequenced Axial and Torsional Cumulative Fatigue: Low Amplitude Followed by High Amplitude Loading," Biaxial/Multiaxial Fatigue and Fracture, ESIS Publication 31, A. Carpinteri, M. De Freitas, and A. Spagnoli, Eds., Elsevier, New York, 2003, pp. 165-182) conditions. In both studies, experiments with the following four load-type sequences were performed: (a) axial/axial, (b) torsional/torsional, (c) axial/torsional, and (d) torsional/axial. In this paper, the cumulative axial and torsional fatigue data generated in the two previous studies are combined to generate a comprehensive cumulative fatigue database on both the load-order and load-type sequence effects. This comprehensive database is used to examine applicability of the Palmgren-langer-Miner linear damage rule and a nonlinear damage curve approach for Haynes 188 subjected to the load-order and load-type sequencing described above. Summations of life fractions from the experiments are compared to the predictions from both the linear and nonlinear cumulative fatigue damage approaches. The significance of load-order versus load-type sequence effects for axial and torsional loading conditions

  8. Appearance of singularities of optical fields under torsion of crystals containing threefold symmetry axes.

    PubMed

    Skab, Ihor; Vasylkiv, Yurij; Zapeka, Bohdan; Savaryn, Viktoriya; Vlokh, Rostyslav

    2011-07-01

    We present an analysis of the effect of torsion stresses on the spatial distribution of optical birefringence in crystals of different point symmetry groups. The symmetry requirements needed so that the optical beam carries dislocations of the phase front are evaluated for the case when the crystals are twisted and the beam closely corresponds to a plane wave. It is shown that the torsion stresses can produce screw-edge, pure screw, or pure edge dislocations of the phase front in the crystals belonging to cubic and trigonal systems. The conditions for appearance of canonical and noncanonical vortices in the conditions of crystal torsion are analyzed. PMID:21734730

  9. The g - 2 muon anomaly in di-muon production with the torsion in LHC

    NASA Astrophysics Data System (ADS)

    Syromyatnikov, A. G.

    2016-06-01

    It was considered within the framework of the conformal gauge gravitational theory CGTG coupling of the standard model fermions to the axial torsion and preliminary discusses the impact of extra dimensions, in particular, in a five-dimensional space-time with Randall-Sundrum metric, where the fifth dimension is compactified on an S1/Z 2 orbifold, which as it turns out is conformally to the fifth dimension flat Euclidean space with permanent trace of torsion, with a compactification radius R in terms of the radius of a CGTG gravitational screening, through torsion in a process Z → μ+μ‑ and LHC data. In general, have come to the correct set of the conformal calibration curvature the Faddeev-Popov diagram technique type, that follows directly from dynamics. This leads to the effect of restrictions on neutral spin currents of gauge fields by helicity and the Regge’s form theory. The diagrams reveals the fact of opening of the fine spacetime structure in a process pp → γ/Z/T → μ+μ‑ with a center-of-mass energy of 14TeV, indicated by dotted lines and texture columns, as a result of p-p collision on 1.3 ṡ 10‑18cm scales from geometric shell gauge bosons of the SM continued by the heavy axial torsion resonance, and even by emerging from the inside into the outside of the ultra-light (freely-frozen in muon’s spin) axial torsion. We then evaluate the contribution of the torsion to the muon anomaly to derive new constraints on the torsion parameters. It was obtained that on the πN scattering through the exchange of axial torsion accounting, the nucleon anomalous magnetic moment in the eikonal phase leads to additive additives which is responsible for the spin-flip in the scattering process, the scattering amplitude is classical and characterized by a strong the torsion coupling ηT≅1. So the scattering of particles, occurs as on the Coulomb center with the charge fT This is the base model which is the g‑2 muon anomaly. The muon anomaly contribution

  10. Some exact solutions with torsion in 5D Einstein-Gauss-Bonnet gravity

    SciTech Connect

    Canfora, F.; Giacomini, A.; Willison, S.

    2007-08-15

    Exact solutions with torsion in Einstein-Gauss-Bonnet gravity are derived. These solutions have a cross product structure of two constant curvature manifolds. The equations of motion give a relation for the coupling constants of the theory in order to have solutions with nontrivial torsion. This relation is not the Chern-Simons combination. One of the solutions has an AdS{sub 2}xS{sup 3} structure and is so the purely gravitational analogue of the Bertotti-Robinson space-time where the torsion can be seen as the dual of the covariantly constant electromagnetic field.

  11. Theoretical-experimental correlation for buckling of composite cylinders under combined compression and torsion

    NASA Technical Reports Server (NTRS)

    Herakovich, C. T.

    1978-01-01

    Comparison between theory and experiment for buckling of laminated graphite-epoxy and boron-epoxy cylinders under combined compression and torsion are presented. The experimental results are compared to a theory by Wu. It is shown that there is excellent agreement between theory and experiment for pure torsional loading (positive and negative), experimental buckling loads for pure compression are well below the predicted values, and good correlation is exhibited between theory and experiment for buckling under combined loading when compared in the form of normalized buckling interaction diagrams in axial-torsional load space.

  12. Eye torsion and the apparent horizon under head tilt and visual field rotation

    NASA Technical Reports Server (NTRS)

    Merker, B. H.; Held, R.

    1981-01-01

    Two different experimental manipulations, namely head tilt and the viewing of a visual display rotating around the line of sight, induce torsional displacements of the eyes and a tilting of the apparent horizon. The present study examines the routes by which visual (field rotation) and otolith-proprioceptive (head tilt) sources of afference influence horizon judgments. In particular, the relationship between torsional eye movements and horizon estimates is addressed. The results indicate that visual and otolith-proprioceptive information sum directly in their influence on eye torsion, but interact more complexly in horizon estimates, indicating a dissociation of their central determinants.

  13. Torsional stresses in box beams with cross sections partially restrained against warping

    NASA Technical Reports Server (NTRS)

    Ebner, Hans

    1934-01-01

    The present report gives a method for computing the torsion of boxes with thin shear-resistant or simply tension-resistant walls under any torsional load, support and dimension. The final stress condition is developed from that of a principal system with unconstrained sectional warping corresponding to Bredt's formula and an additional stress condition due to constrained cross-sectional warping. This is computed by means of the deflection condition of the principal system from a statically indeterminate calculation. Conformably, the torsional rigidity of the final system is derived from that of the principal system with unconstrained sectional buckling.

  14. Torsion sensors of high sensitivity and wide dynamic range based on a graphene woven structure

    NASA Astrophysics Data System (ADS)

    Yang, Tingting; Wang, Yan; Li, Xinming; Zhang, Yangyang; Li, Xiao; Wang, Kunlin; Wu, Dehai; Jin, Hu; Li, Zhihong; Zhu, Hongwei

    2014-10-01

    Due to its unique electromechanical properties, nanomaterial has become a promising material for use in the sensing elements of strain sensors. Tensile strain is the type of deformation most intensively studied. Torsion is another deformation occurring in everyday life, but is less well understood. In the present study a torsion sensor was prepared by wrapping woven graphene fabrics (GWFs) around a polymer rod at a specific winding angle. The GWF sensor showed an ultra-high sensitivity with a detection limit as low as 0.3 rad m-1, indicating its potential application in the precise measurement of low torsions. The GWFs were pre-strained before wrapping on polydimethylsiloxane (PDMS) to improve the tolerance of the sensor to high torsion. The microstructure of the GWFs at different torsion levels was monitored using an optical microscope. The results demonstrated the formation of GWF waves and cracks under high torsion, a critical factor in determining the electromechanical properties of a GWF sensor.Due to its unique electromechanical properties, nanomaterial has become a promising material for use in the sensing elements of strain sensors. Tensile strain is the type of deformation most intensively studied. Torsion is another deformation occurring in everyday life, but is less well understood. In the present study a torsion sensor was prepared by wrapping woven graphene fabrics (GWFs) around a polymer rod at a specific winding angle. The GWF sensor showed an ultra-high sensitivity with a detection limit as low as 0.3 rad m-1, indicating its potential application in the precise measurement of low torsions. The GWFs were pre-strained before wrapping on polydimethylsiloxane (PDMS) to improve the tolerance of the sensor to high torsion. The microstructure of the GWFs at different torsion levels was monitored using an optical microscope. The results demonstrated the formation of GWF waves and cracks under high torsion, a critical factor in determining the

  15. Balancing Control for Dispersed Generators Considering Torsional Torque Suppression and AVR Performance for Synchronous Generators

    NASA Astrophysics Data System (ADS)

    Senjyu, Tomonobu; Omine, Eitaro; Hayashi, Daisuke; Muhando, Endusa Billy; Yona, Atsushi; Funabashi, Toshihisa

    Electric utility deregulation made possible for PPSs (Power Producer and Supplier) to entry the electricity market. PPSs are supposed to achieve 30-minute balancing control for stable supply of electric power. Meanwhile, load rejection and instantaneous voltage drop greatly affect turbine shafting, that is torsional torque oscillation. Therefore, PPSs have to consider reduction of torsional torque to prevent generator shaft damage. This paper propose the control system which enables to achieve both 30-minute balancing control and reduction of torsional torque by using H∞ controller. The effectiveness of proposed controller will be verified by using MATLAB.

  16. Structural analysis of hollow blades: Torsional stress analysis of hollow fan blades for aircraft jet engines

    NASA Technical Reports Server (NTRS)

    Ogawa, A.; Sofue, Y.; Isobe, T.

    1979-01-01

    A torsional stress analysis of hollow fans blades by the finite element method is presented. The fans are considered to be double circular arc blades, hollowed 30 percent, and twisted by a component of the centrifugal force by the rated revolution. The effects of blade hollowing on strength and rigidity are discussed. The effects of reinforcing webs, placed in the hollowed section in varying numbers and locations, on torsional rigidity and the convergence of stresses, are reported. A forecast of the 30 percent hollowing against torsional loadings is discussed.

  17. Characterization of tungsten fragmentation in a W-25%Cu composite after high-pressure torsion

    SciTech Connect

    Sabirov, I. Pippan, R.

    2007-10-15

    A coarse-grained W-25%Cu alloy with a tungsten particle size of 2-10 {mu}m is subjected to severe plastic deformation by high-pressure torsion at different temperatures. The evolution of the microstructure with increasing strain is investigated. It is shown that high-pressure torsion deformation causes a strong refinement of tungsten particles. It is found that the tungsten particle fragmentation during high-pressure torsion follows the fractal distribution and demonstrates a multi-fractal behavior. Similarity of this fragmentation process with fragmentation observed in nature at the macro-, micro-, and nano-levels is discussed.

  18. 11-cis retinal torsion: A QTAIM and stress tensor analysis of the S1 excited state

    NASA Astrophysics Data System (ADS)

    Maza, Julio R.; Jenkins, Samantha; Kirk, Steven R.

    2016-05-01

    We investigate torsion about the C11-C12 bond mid-point for the S1 state of 11-cis retinal, using a QTAIM and stress tensor analysis. The QTAIM and stress tensor responses to a torsion ±α increase at a faster rate for the preferred direction of torsion though the CI seam. A QTAIM and stress tensor vector-based analysis provides an alternative way of characterising the asymmetry of the S1 potential energy surface. In the vicinity of the CI seam the ellipticity ε attained minimum values. The application of this analysis to molecular rotary motors is briefly discussed.

  19. A data acquisition and control program for axial-torsional fatigue testing

    NASA Technical Reports Server (NTRS)

    Kalluri, Sreeramesh; Bonacuse, Peter J.

    1989-01-01

    A computer program was developed for data acquisition and control of axial-torsional fatigue experiments. The multitasked, interrupt-driven program was written in Pascal and Assembly. This program is capable of dual-channel control and six-channel data acquisition. It can be utilized to perform inphase and out-of-phase axial-torsional isothermal fatigue or deformation experiments. The program was successfully used to conduct inphase axial-torsional fatigue experiments on 304 stainless steel at room temperature and on Hastelloy X at 800 C. The details of the software and some of the results generated to date are presented.

  20. Usefulness of CT imaging for segmental lung lobe torsion without typical radiographic imaging in a Pomeranian.

    PubMed

    Choi, Mihyun; Lee, Namsoon; Keh, Seoyeon; Choi, Heeyeon; Yim, Yoonji; Kim, Hyunwook; Jung, Joohyun; Choi, Mincheol

    2015-02-01

    A 3-year-old, intact female Pomeranian presented with a 1-month history of coughing. Thoracic radiography showed focal infiltration of the left cranial lung lobe and widening of the cranial mediastinum. Subsequent computed tomography revealed torsion of the caudal segment of the left cranial lung lobe, which was confirmed by exploratory thoracotomy. There was no apparent underlying etiology for the condition. To the authors' knowledge, this is the first report of lung lobe torsion in this breed and the first detailed CT imaging report for segmental lung lobe torsion. PMID:25728251

  1. MSTor version 2013: A new version of the computer code for the multi-structural torsional anharmonicity, now with a coupled torsional potential

    NASA Astrophysics Data System (ADS)

    Zheng, Jingjing; Meana-Pañeda, Rubén; Truhlar, Donald G.

    2013-08-01

    We present an improved version of the MSTor program package, which calculates partition functions and thermodynamic functions of complex molecules involving multiple torsions; the method is based on either a coupled torsional potential or an uncoupled torsional potential. The program can also carry out calculations in the multiple-structure local harmonic approximation. The program package also includes seven utility codes that can be used as stand-alone programs to calculate reduced moment of inertia matrices by the method of Kilpatrick and Pitzer, to generate conformational structures, to calculate, either analytically or by Monte Carlo sampling, volumes for torsional subdomains defined by Voronoi tessellation of the conformational subspace, to generate template input files for the MSTor calculation and Voronoi calculation, and to calculate one-dimensional torsional partition functions using the torsional eigenvalue summation method. Restrictions: There is no limit on the number of torsions that can be included in either the Voronoi calculation or the full MS-T calculation. In practice, the range of problems that can be addressed with the present method consists of all multitorsional problems for which one can afford to calculate all the conformational structures and their frequencies. Unusual features: The method can be applied to transition states as well as stable molecules. The program package also includes the hull program for the calculation of Voronoi volumes, the symmetry program for determining point group symmetry of a molecule, and seven utility codes that can be used as stand-alone programs to calculate reduced moment-of-inertia matrices by the method of Kilpatrick and Pitzer, to generate conformational structures, to calculate, either analytically or by Monte Carlo sampling, volumes of the torsional subdomains defined by Voronoi tessellation of the conformational subspace, to generate template input files, and to calculate one-dimensional torsional

  2. 21 CFR 310.532 - Drug products containing active ingredients offered over-the-counter (OTC) to relieve the...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 5 2010-04-01 2010-04-01 false Drug products containing active ingredients offered over-the-counter (OTC) to relieve the symptoms of benign prostatic hypertrophy. 310.532 Section 310.532 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS FOR HUMAN USE NEW DRUGS Requirements...

  3. 21 CFR 310.532 - Drug products containing active ingredients offered over-the-counter (OTC) to relieve the...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 5 2014-04-01 2014-04-01 false Drug products containing active ingredients offered over-the-counter (OTC) to relieve the symptoms of benign prostatic hypertrophy. 310.532 Section 310.532 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS FOR HUMAN USE NEW DRUGS Requirements...

  4. 40 CFR 270.90 - Does my RAP grant me any rights or relieve me of any obligations?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 27 2011-07-01 2011-07-01 false Does my RAP grant me any rights or... PROGRAM Remedial Action Plans (RAPs) General Information § 270.90 Does my RAP grant me any rights or relieve me of any obligations? The provisions of § 270.4 apply to RAPs. (Note: The provisions of §...

  5. 40 CFR 270.90 - Does my RAP grant me any rights or relieve me of any obligations?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 28 2012-07-01 2012-07-01 false Does my RAP grant me any rights or... PROGRAM Remedial Action Plans (RAPs) General Information § 270.90 Does my RAP grant me any rights or relieve me of any obligations? The provisions of § 270.4 apply to RAPs. (Note: The provisions of §...

  6. 40 CFR 270.90 - Does my RAP grant me any rights or relieve me of any obligations?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 28 2013-07-01 2013-07-01 false Does my RAP grant me any rights or... PROGRAM Remedial Action Plans (RAPs) General Information § 270.90 Does my RAP grant me any rights or relieve me of any obligations? The provisions of § 270.4 apply to RAPs. (Note: The provisions of §...

  7. 40 CFR 270.90 - Does my RAP grant me any rights or relieve me of any obligations?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 27 2014-07-01 2014-07-01 false Does my RAP grant me any rights or... PROGRAM Remedial Action Plans (RAPs) General Information § 270.90 Does my RAP grant me any rights or relieve me of any obligations? The provisions of § 270.4 apply to RAPs. (Note: The provisions of §...

  8. 40 CFR 270.90 - Does my RAP grant me any rights or relieve me of any obligations?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Does my RAP grant me any rights or... PROGRAM Remedial Action Plans (RAPs) General Information § 270.90 Does my RAP grant me any rights or relieve me of any obligations? The provisions of § 270.4 apply to RAPs. (Note: The provisions of §...

  9. 21 CFR 310.532 - Drug products containing active ingredients offered over-the-counter (OTC) to relieve the...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 5 2011-04-01 2011-04-01 false Drug products containing active ingredients offered over-the-counter (OTC) to relieve the symptoms of benign prostatic hypertrophy. 310.532 Section 310.532 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS FOR HUMAN USE NEW DRUGS Requirements...

  10. Extramedical Use of Prescription Pain Relievers by Youth Aged 12 to 21 Years in the United States

    PubMed Central

    Meier, Elizabeth A.; Troost, Jonathan P.; Anthony, James C.

    2015-01-01

    Objective To identify when youth are most likely to start using prescription pain relievers to get high or for other unapproved indications outside the boundaries of what a prescribing physician might intend (ie, extramedical use). Design Cross-sectional surveys of adolescent cohorts, 2004 to 2008. Setting The United States. Participants Large nationally representative samples of youth in the United States who had been assessed for the 2004 through 2008 National Surveyon Drug Use and Health, yielding data from 138 729 participants aged 12 to 21 years. Main Outcome Measures Estimated age-specific risk of starting extramedical use of prescription pain relievers, year by year, and confirmation of age at peak risk by tracing the experience of individual cohorts during this period. Results The estimated peak risk of starting extramedical use of prescription pain relievers occurs in midadolescence, well before the college years. The age at peak risk is 16 years, when an estimated 2% to 3% become newly incident users. Smaller risk estimates are observed at age 12 to 14 years and at age 19 to 21 years. Conclusions For initiatives to prevent youth from using prescription pain relievers to get high or for other un-approved indications, a focus on the last year of high school and the post–secondary school years may be too little too late. Practice-based approaches are needed in addition to public health interventions based on effective alcohol and tobacco prevention programs during the earlier adolescent years. PMID:22566515

  11. Kinetic mechanism of an aldehyde reductase of Saccharomyces cerevisiae that relieves toxicity of furfural and 5-hydroxymethylfurfural

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An effective means of relieving the toxicity of furan aldehydes, furfural (FFA) and 5-hydroxymethylfurfural (HMF), on fermenting organisms is essential for achieving efficient fermentation of lignocellulosic biomass to ethanol and other products. Ari1p, an aldehyde reductase from Saccharomyces cerev...

  12. Ultrasound-guided percutaneous antegrade hydropropulsion to relieve ureteral obstruction in a pet guinea pig (Cavia porcellus)

    PubMed Central

    Eshar, David; Lee-Chow, Bridget; Chalmers, Heather J.

    2013-01-01

    Severe hydroureter and hydronephrosis secondary to ureteral obstruction by calculus were present in a guinea pig. A palliative ultrasound-guided percutaneous antegrade hydropropulsion was performed under general anesthesia to relieve the ureteral obstruction and the associated clinical signs. We describe the technique and the considerations for its potential application in similar cases. PMID:24293674

  13. Optimum Design of Composite Sandwich Structures Subjected to Combined Torsion and Bending Loads

    NASA Astrophysics Data System (ADS)

    Li, Xiang; Li, Gangyan; Wang, Chun H.; You, Min

    2012-06-01

    This research is motivated by the increase use of composite sandwich structures in a wide range of industries such as automotive, aerospace and civil infrastructure. To maximise stiffness at minimum weight, the paper develops a minimum weight optimization method for sandwich structure under combined torsion and bending loads. We first extend the minimum-weight design of sandwich structures under bending load to the case of torsional deformation and then present optimum solutions for the combined requirements of both bending and torsional stiffness. Three design cases are identified for a sandwich structure required to meet multiple design constraints of torsion and bending stiffness. The optimum solutions for all three cases are derived. To illustrate the newly developed optimum design solutions, numerical examples are presented for sandwich structures made of either isotropic face skins or orthotropic composite face skins.

  14. Simultaneous normal and torsional force measurement by cantilever surface contour analysis

    NASA Astrophysics Data System (ADS)

    Kumanchik, Lee; Schmitz, Tony; Pratt, Jon

    2011-05-01

    This study presents an alternative to the current Hooke's law-based force relation between rectangular cantilever deflection and applied force. In the new approach, a transduction constant is presented that (1) includes no cross-talk between torsion and normal force components, (2) is independent of the load application point, and (3) does not depend on the cantilever beam length. Rather than measuring the cantilever deformation at a single point (such as the tip location), it is measured at multiple adjacent points using scanning white light interferometry to provide a three-dimensional description of the cantilever deformation during loading. This measurement, processed by a force relation based on a superposition of deflections derived from Euler-Bernoulli bending theory and St Venant's torsion theory, provides the vertical, axial, and torsional force components simultaneously. Experimental results are compared to force predictions for the vertical and torsional components using macro-scale cantilevers under mass loading. An uncertainty analysis is also provided.

  15. On the interpretation of combined torsion and tension tests of thin-wall tubes

    NASA Technical Reports Server (NTRS)

    Prager, W

    1948-01-01

    General ways of testing thin-wall tubes under combined tension and torsion as a means of checking the various theories of plasticity are discussed. Suggestions also are given for the interpretation of the tests.

  16. Contrast-enhanced ultrasonographic findings in three dogs with lung lobe torsion

    PubMed Central

    CAIVANO, Domenico; BIRETTONI, Francesco; BUFALARI, Antonello; MONTE, Valentina DE; ANGELI, Giovanni; GIORGI, Maria Elena; PATATA, Valentina; PORCIELLO, Francesco

    2015-01-01

    Lung lobe torsion is rare but life-threatening condition in the dog. Thoracic radiographs and conventional ultrasonography cannot be conclusive for the diagnosis, and computed tomography is useful but is limited by cost and availability. This report describes the findings of contrast-enhanced ultrasonography in 3 dogs with lung lobe torsion. Contrast-enhanced ultrasonography showed the absence or reduction of pulmonary vascularization secondary to twisting of the lung lobe around its bronchovascular pedicle in all three dogs. Moreover, contrast-enhanced ultrasonography distinguished partial pulmonary atelectasis from a lung lobe torsion. These preliminary results suggest that contrast-enhanced ultrasonography can improve the accuracy of conventional ultrasonography for detection of pulmonary blood flow compromise in dogs with lung lobe torsion. PMID:26498403

  17. Dirac quasinormal modes of Chern-Simons and BTZ black holes with torsion

    NASA Astrophysics Data System (ADS)

    Bécar, Ramón; González, P. A.; Vásquez, Y.

    2014-01-01

    We study Chern-Simons black holes in d dimensions and we calculate analytically the quasinormal modes of fermionic perturbations. Also, we consider as background the five-dimensional Chern-Simons black hole with torsion and the BTZ black hole with torsion. We have found that the quasinormal modes depend on the highest power of curvature present in the Chern-Simons theory, such as that which occurs for the quasinormal modes of scalar perturbations. We also show that the effect of the torsion is to modify the real part of the quasinormal frequencies, which modify the oscillation frequency of the field for the five-dimensional case. However, for the BTZ black hole with torsion, the effect is to modify the imaginary part of these frequencies, that is, the relaxation time for the decay of the black hole perturbation. The imaginary part of the quasinormal frequencies is negative, which guarantees the stability of these black holes under fermionic field perturbations.

  18. Microwave Spectroscopy of Trans-Ethyl Methyl Ether in the Torsionally Excited State 3

    NASA Astrophysics Data System (ADS)

    Kobayashi, Kaori; Murata, Keigo; Tsunekawa, Shozo; Ohashi, Nobukimi

    2010-06-01

    The trans-ethyl methyl ether molecule (CH_3CH_2OCH_3) has two methyl group internal rotors which are equivalent to the two vibrational motions, ν28 and ν29. There is another low-lying torsional motion which is a skeltal torsion (ν30) and does not cause splitting. The microwave spectra of the trans-ethyl methyl ether molecule in the ν28 = 1, ν29 = 1, and ν30 = 1 have been studied and interactions between these states were discussed. In this paper we report results on the ν30 = 2, and 3 state. The analysis based on Hougen's tunneling matrix formulation considering two methyl groups are used. We try to interpret tunneling parameters obtained in the present analysis quantitatively from the viewpoint of torsion-torsion interaction.

  19. An improved torsion pendulum based on image processing for single fibers

    NASA Astrophysics Data System (ADS)

    Yu, Longteng; Liu, Dabiao; Peng, Kai; He, Yuming

    2016-07-01

    An improved torsion pendulum technique based on image processing is developed, which allows the measurement of the torsional oscillation of individual fibers. The torsion pendulum is composed of a length of fiber specimen and a ring-shaped mass attached to one of its ends. The oscillation motion of the mass is recorded with a video camera overhead. An image processing method is developed to accurately calculate the twist angle of single fibers in the torsion pendulum. All images are firstly converted into matrices and then the edge detection is applied to calculate the twist angle at corresponding time to obtain the angle-time relation. The oscillation frequency is determined by the fast Fourier transform (FFT) method. By applying this technique, we have performed tests on four types of fibers, namely T300 carbon fiber, copper, silver and tungsten wires. The longitudinal shear modulus measured for each type of these fibers is presented.

  20. Intershell Interaction in a Double Wall Carbon Nanotube with Determined Chiral Indices under a Torsional Strain

    NASA Astrophysics Data System (ADS)

    Lin, Letian; Cui, Taoran; Washburn, Sean; Qin, Lu-Chang

    2011-03-01

    We have used a double wall carbon nanotube to build a torsional pendulum. The nanotube worked as a torsional bearing for a metal block. An external electric field was used to rotate the metal block to cause a fully elastic torsional deformation on the nanotube. Nano-beam electron diffraction patterns were taken before and while the nanotube was twisted. By analysis of the shift of the diffraction patterns, we were able to determine the nanotube chiral indices and measure the inner-shell torisonal responses to the torsional stress applied on the outer-shell. The inter-shell interactions and nanotube shear modulus were also calculated and discussed in connection to the theoretical estimations.

  1. Raman spectra of gases. XVI - Torsional transitions in ethanol and ethanethiol

    NASA Technical Reports Server (NTRS)

    Durig, J. R.; Bucy, W. E.; Wurrey, C. J.; Carreira, L. A.

    1975-01-01

    The Raman spectra of gaseous ethanol and ethanethiol have been investigated. Thiol torsional fundamentals for the gauche conformer of EtSH and EtSD have been observed and the asymmetric potential function for this vibration has been calculated. Methyl torsional transitions and overtones have also been observed for both of these molecules. Barriers to internal rotation for the methyl top are calculated to be 3.77 and 3.84 kcal/mol for the EtSH and EtSD compounds, respectively. Hydroxyl torsional fundamentals were observed at 207 and 170 per cm in the EtOH and EtOD spectra, respectively. Overtones of the methyl torsion in both molecules yield a barrier to internal rotation of 3.62 kcal/mol for the gauche conformer.

  2. Adnexal Incarceration in a Posterior Pelvic Peritoneal Defect Mimics Ovarian Torsion.

    PubMed

    Jackson, Amanda M; Hope, Erica R; Phippen, Neil T

    2015-01-01

    Surgery for suspected ovarian torsion sometimes reveals unexpected sources of pelvic pain, such as internal hernias, adhesions, or anatomic defects. A 23-year-old nulligravida with Alagille syndrome was taken to the operating room with suspected ovarian torsion. Intraoperatively, the right adnexa bulged out of a right-sided, posterior peritoneal cleft that incarcerated most of the enlarged ovary. No ovarian torsion was identified. The left adnexa appeared to be normal; however, it dwelled within a left-sided posterior peritoneal cleft. The bilateral posterior peritoneal defects that housed the adnexa were likely of congenital etiology. Although adnexal incarceration is a rare finding at surgery for suspected ovarian torsion, it should be part of the differential diagnosis when evaluating acute pelvic pain. PMID:26044591

  3. Torsion of Fatty Appendage of Falciform Ligament: Acute Abdomen in a Child.

    PubMed

    Maccallum, Caroline; Eaton, Sarah; Chubb, Daniel; Franzi, Stephen

    2015-01-01

    Torsion of the fatty appendage of the falciform ligament is an extremely rare condition that leads to severe abdominal pain and raised inflammatory markers. It can be recognised on ultrasound or CT scan. The pathophysiology is the same as that involved in the more common torsion and/or infarction of the greater omentum or epiploic appendages. The condition is best managed conservatively with anti-inflammatory analgesia, and the early recognition of this type of torsion may prevent unnecessary operative intervention to look for a source of abdominal pain. There have been five reported adult cases of a torted fatty appendage of the falciform ligament identified on ultrasound and CT scan, but no paediatric cases. We report a case of torsion of the fatty appendage of the falciform ligament in a ten-year-old boy and describe its imaging characteristics on CT scan. PMID:26664796

  4. Torsion of Fatty Appendage of Falciform Ligament: Acute Abdomen in a Child

    PubMed Central

    Maccallum, Caroline; Eaton, Sarah; Chubb, Daniel; Franzi, Stephen

    2015-01-01

    Torsion of the fatty appendage of the falciform ligament is an extremely rare condition that leads to severe abdominal pain and raised inflammatory markers. It can be recognised on ultrasound or CT scan. The pathophysiology is the same as that involved in the more common torsion and/or infarction of the greater omentum or epiploic appendages. The condition is best managed conservatively with anti-inflammatory analgesia, and the early recognition of this type of torsion may prevent unnecessary operative intervention to look for a source of abdominal pain. There have been five reported adult cases of a torted fatty appendage of the falciform ligament identified on ultrasound and CT scan, but no paediatric cases. We report a case of torsion of the fatty appendage of the falciform ligament in a ten-year-old boy and describe its imaging characteristics on CT scan. PMID:26664796

  5. Torsional vibration of single-walled carbon nanotubes using doublet mechanics

    NASA Astrophysics Data System (ADS)

    Fatahi-Vajari, Alireza; Imam, Ali

    2016-08-01

    This paper investigates the torsional vibration of single-walled carbon nanotubes (SWCNTs) using a new approach based on doublet mechanics (DM) incorporating explicitly scale parameter and chiral effects. A fourth-order partial differential equation that governs the torsional vibration of nanotubes is derived. Using DM, an explicit equation for the natural frequency in terms of geometrical and mechanical property of CNTs is obtained for both the Zigzag and Armchair nanotube for the torsional vibration mode. It is shown that chiral effects along with the scale parameter play a significant role in the vibration behavior of SWCNTs in torsional vibration mode. Such effects decrease the natural frequency obtained by DM compared to the classical continuum mechanics and nonlocal theory predictions. However, with increase in the length and/or the radius of the tube, the effect of the chiral and scale parameter on the natural frequency decreases.

  6. Microstructure evolution in solution treated Ti15Mo alloy processed by high pressure torsion

    SciTech Connect

    Janeček, Miloš; Čížek, Jakub; Stráský, Josef; Václavová, Kristína; Hruška, Petr; Polyakova, Veronika; Gatina, Svetlana; Semenova, Irina

    2014-12-15

    Microstructure evolution and mechanical properties of ultra-fine grained Ti15Mo alloy processed by high pressure torsion were investigated. High pressure torsion straining resulted in strong grain refinement as-observed by transmission electron microscopy. Microhardness and light microscopy showed two distinct regions — (i) a central region with radial material flow and low microhardness (340 HV) and (ii) a peripheral region with rotational material flow and high microhardness (430 HV). Positron annihilation spectroscopy showed that the only detectable defects in the material are dislocations, whose density increases with the radial distance and the number of high pressure torsion revolutions. The local chemical environment around defects does not differ significantly from the average composition. - Highlights: • Beta-Ti alloy Ti15Mo was processed by high pressure torsion (HPT). • Lateral inhomogeneity of the microstructure and microhardness was found. • Dislocations are the only lattice defects detectable by positron annihilation. • Molybdenum is not preferentially segregated along dislocation cores.

  7. ARA 290 relieves pathophysiological pain by targeting TRPV1 channel: Integration between immune system and nociception.

    PubMed

    Zhang, Wenjia; Yu, Guanling; Zhang, Mengyuan

    2016-02-01

    ARA 290 is an erythropoietin-derived polypeptide that possesses analgesic and tissue protective effect in many diseases such as diabetes and cancer. The analgesic effect of ARA 290 is mediated by its anti-inflammatory and immunomodulatory functions, or more specifically, by targeting the innate repair receptor (IRR) to down-regulate inflammation to alleviate neuropathic pain. However, whether other mechanisms or pathways are involved in ARA 290-mediated analgesic effect remains elusive. In this study, we are particularly interested in whether ARA 290 could directly target peripheral nociceptors by blocking or influencing receptors in pain sensation. Using calcium imaging, cell culture and behavioral tests, we demonstrated that ARA 290 was able to specifically inhibit TRPV1 channel activity, and relieve the mechanical hypersensitivity induced by capsaicin. Our study suggested that ARA 290 could potentially function as a novel antagonist for TRPV1 channel. This finding would not only contribute to the development of new pain treatment using ARA 290, but also help to improve our understanding of the integration between the immune system and the peripheral nervous system. PMID:26774587

  8. The Effectiveness of Cupping Therapy on Relieving Chronic Neck and Shoulder Pain: A Randomized Controlled Trial.

    PubMed

    Chi, Lee-Mei; Lin, Li-Mei; Chen, Chien-Lin; Wang, Shu-Fang; Lai, Hui-Ling; Peng, Tai-Chu

    2016-01-01

    The research aimed to investigate the effectiveness of cupping therapy (CT) in changes on skin surface temperature (SST) for relieving chronic neck and shoulder pain (NSP) among community residents. A single-blind experimental design constituted of sixty subjects with self-perceived NSP. The subjects were randomly allocated to two groups. The cupping group received CT at SI 15, GB 21, and LI 15 acupuncture points, and the control group received no intervention. Pain was assessed using the SST, visual analog scale (VAS), and blood pressure (BP). The main results were SST of GB 21 acupuncture point raised from 30.6°C to 32.7°C and from 30.7°C to 30.6°C in the control group. Neck pain intensity (NPI) severity scores were reduced from 9.7 to 3.6 in the cupping group and from 9.7 to 9.5 in the control group. The SST and NPI differences between the groups were statistically significant (P < 0.001). One treatment of CT is shown to increase SST. In conjunction with the physiological effect the subjective experience of NSP is reduced in intensity. Further studies are required to improve the understanding and potential long-term effects of CT. PMID:27073404

  9. Back massage intervention for relieving lower back pain in puerperal women: A randomized control trial study.

    PubMed

    Lee, Hsiu-Jung; Ko, Yi-Li

    2015-05-01

    This study evaluates the effectiveness of a back massage (BM) intervention in relieving lower back pain (LBP) in post-partum women.This is a randomized controlled trial study. Sixty normal spontaneous delivery women (response rate: 96.7%), who gave birth at our hospital, participated in this study from February to May of 2012. We randomly assigned 30 women to the experimental group and 30 women to the control group. During the 1 month post-partum period, the women in the experimental group received a BM for 5 consecutive days, whereas the women in the control group received routine care only. The LBP score was assessed according to a pain visual analog scale. After 5 days of intervention, the experimental group (n = 30) experienced significantly less LBP than did the control group (n = 30) (2.97 ± 1.71 vs. 4.43 ± 1.77, t = 3.26, P = 0.002). BM therapy can effectively reduce LBP during the first post-partum month. Additional studies are required to confirm the effects of BM therapy during extended post-partum periods. PMID:26125572

  10. Intractable itch relieved by 4-phenylbutyrate therapy in patients with progressive familial intrahepatic cholestasis type 1

    PubMed Central

    2014-01-01

    Background Progressive familial intrahepatic cholestasis type 1 (PFIC1), an inherited liver disease caused by mutations in ATP8B1, progresses to severe cholestasis with a sustained intractable itch. Currently, no effective therapy has been established for PFIC1. Decreased function of the bile salt export pump (BSEP) in hepatocytes is suggested to be responsible for the severe cholestasis observed in PFIC1. We found a previously unidentified pharmacological effect of 4-phenylbutyrate (4PB) that increases the expression and function of BSEP. Here, we tested 4PB therapy in three patients with PFIC1. Methods The therapeutic potency of 4PB in these patients was tested by oral administration of this drug with gradually increasing dosage (200, 350, and 500 mg/kg/day) for 6 months. Biochemical, histological, and clinical data were collected. Results 4PB therapy had no beneficial effect on the patients’ liver functions, as assessed by biochemical and histological analyses, despite an increase in hepatic BSEP expression. However, therapy with 4PB at a dosage of 350 or 500 mg/kg/day significantly relieved the intractable itch. Serum levels of potential pruritogens in cholestasis were much higher than the reference ranges during the 4PB therapy. Conclusions 4PB therapy may be a new medication for patients with intractable cholestatic pruritus and may improve quality of life for patients and their families. PMID:25022842

  11. Iliac Artery Stent Placement Relieves Claudication in Patients with Iliac and Superficial Femoral Artery Lesions

    SciTech Connect

    Ichihashi, Shigeo Higashiura, Wataru; Itoh, Hirofumi; Sakaguchi, Shoji; Kichikawa, Kimihiko

    2013-06-15

    Purpose. To evaluate the efficacy of iliac artery stent placement for relief of claudication in patients with both iliac and superficial femoral artery (SFA) lesions. Methods. Stent placement for only iliac artery occlusive disease was performed in 94 limbs (74 patients) with both iliac and SFA occlusive disease on the same limb. All procedures were performed because intermittent claudication did not improve after continuation of antiplatelet medication therapy and home-based exercise for 3 months. Rutherford classification was 2 in 20 limbs and 3 in 74 limbs. Patients with critical limb ischemia were excluded. Median duration of follow-up was 40 months. Primary patency rates of the iliac stent, clinical improvement rates, and risk factors for requiring additional SFA procedures were evaluated. Results. Primary patency rates of the iliac stent at 1, 3, 5, and 7 years were 97, 93, 79, and 79 %, respectively. The initial clinical improvement rate was 87 %. Continued clinical improvement rates at 1, 3, 5, and 7 years were 87, 81, 69, and 66 %, respectively. SFA Trans-Atlantic Inter-Society Consensus (TASC) II C/D lesion was a significant risk factor for requiring additional SFA procedures. Conclusion. Intermittent claudication was relieved by iliac stent placement in most patients with both iliac and SFA lesions. Thus, the indications for treatment of the SFA intended for claudicants should be evaluated after treatment of the iliac lesion.

  12. A Novel Selective Prostaglandin E2 Synthesis Inhibitor Relieves Pyrexia and Chronic Inflammation in Rats.

    PubMed

    Sugita, Ryusuke; Kuwabara, Harumi; Sugimoto, Kotaro; Kubota, Kazufumi; Imamura, Yuichiro; Kiho, Toshihiro; Tengeiji, Atsushi; Kawakami, Katsuhiro; Shimada, Kohei

    2016-04-01

    Prostaglandin E2 (PGE2) is a terminal prostaglandin in the cyclooxygenase (COX) pathway. Inhibition of PGE2 production may relieve inflammatory symptoms such as fever, arthritis, and inflammatory pain. We report here the profile of a novel selective PGE2 synthesis inhibitor, compound A [N-[(1S,3S)-3-carbamoylcyclohexyl]-1-(6-methyl-3-phenylquinolin-2-yl)piperidine-4-carboxamide], in animal models of pyrexia and inflammation. The compound selectively suppressed the synthesis of PGE2 in human alveolar adenocarcinoma cell line A549 cells and rat macrophages. In the lipopolysaccharide-induced pyrexia model, this compound selectively reduced PGE2 production in cerebrospinal fluid and showed an anti-pyretic effect. In the adjuvant-induced arthritis model, compound A therapeutically decreased foot swelling in the established arthritis. Our data demonstrates that selective suppression of PGE2 synthesis shows anti-pyretic and anti-inflammatory effects, suggesting that selective PGE2 synthesis inhibitors can be applied as an alternative treatment to nonsteroidal, anti-inflammatory drugs (NSAIDs) or COX-2-selective inhibitors. PMID:26923147

  13. Curcumin relieves TPA-induced Th1 inflammation in K14-VEGF transgenic mice.

    PubMed

    Sun, Jun; Zhao, Yi; Jin, Hairong; Hu, Jinhong

    2015-04-01

    Curcumin has been confirmed to have anti-inflammatory properties in addition to the ability to decrease the expression of pro-inflammatory cytokines in keratinocytes. It was suggested that the interleukin-23 (IL-23)/IL-17A cytokine axis played a critical role in the pathogenesis of 12-O-tetradecanoyl phorbol 12-myristate 13-acetate (TPA)-induced K14-VEGF transgenic psoriasis-like mice model. Here, we report that topical use of a curcumin gel formulation inhibited TPA-induced Th1 inflammation in K14-VEGF transgenic mice ears but not Th17 inflammation as expected. Real-time PCR showed that mRNA levels of IL-23, IL-17A, IL-22, IL-6 and TNFα cytokines failed to increase after TPA-induction in K14-VEGF transgenic mice ear skin; but the mRNA level of IFNγ increased significantly at the same time. Furthermore, TPA-induction up-regulated the TCRγδ protein but failed to impact the CCR6 protein, which means that the proliferation of γδ T cells is incapable of IL-17A production. We find that curcumin is capable of relieving TPA-induced inflammation by directly down-regulating IFNγ production. In conclusion, curcumin inhibits TPA-induced Th1 inflammation in K14-VEGF transgenic mice which has not been previously described. PMID:25682767

  14. ALG-2 activates the MVB sorting function of ALIX through relieving its intramolecular interaction

    PubMed Central

    Sun, Sheng; Zhou, Xi; Corvera, Joe; Gallick, Gary E; Lin, Sue-Hwa; Kuang, Jian

    2015-01-01

    The modular adaptor protein ALIX is critically involved in endosomal sorting complexes required for transport (ESCRT)-mediated multivesicular body (MVB) sorting of activated epidermal growth factor receptor (EGFR); however, ALIX contains a default intramolecular interaction that renders ALIX unable to perform this ESCRT function. The ALIX partner protein ALG-2 is a calcium-binding protein that belongs to the calmodulin superfamily. Prompted by a defined biological function of calmodulin, we determined the role of ALG-2 in regulating ALIX involvement in MVB sorting of activated EGFR. Our results show that calcium-dependent ALG-2 interaction with ALIX completely relieves the intramolecular interaction of ALIX and promotes CHMP4-dependent ALIX association with the membrane. EGFR activation induces increased ALG-2 interaction with ALIX, and this increased interaction is responsible for increased ALIX association with the membrane. Functionally, inhibition of ALIX activation by ALG-2 inhibits MVB sorting of activated EGFR as effectively as inhibition of ALIX interaction with CHMP4 does; however, inhibition of ALIX activation by ALG-2 does not affect cytokinetic abscission or equine infectious anemia virus (EIAV) budding. These findings indicate that calcium-dependent ALG-2 interaction with ALIX is specifically responsible for generating functional ALIX that supports MVB sorting of ubiquitinated membrane receptors.

  15. A case of a bloated face: SVC syndrome relieved by an endovascular approach.

    PubMed

    Szerlip, Molly; Singh, Gundeep; Luft, Ulrich C

    2012-02-01

    Superior vena cava (SVC) syndrome, or obstruction of blood returning from the head and upper extremities, is a syndrome that is rapidly increasing in the cardiovascular patient population due to the increasing use of transvenous devices such as permanent pacemakers, implantable cardioverter defibrillators (ICDs), and indwelling venous access devices for hemodialysis. This syndrome in the past has been seen predominately in the cancer population with malignancy being the most common reason for SVC syndrome. The management of this syndrome has largely been with a medical/supportive care approach or with surgical bypass. Given the advancement in the field of endovascular interventions and the increasing expertise in performing these procedures, an endovascular approach to relieving the SVC obstruction is rapidly becoming the treatment of choice for these patients. We describe a case of a patient who had a chronic indwelling port-a-cath who developed SVC syndrome, which was treated with an endovascular approach with stenting of the SVC/brachiocephalic vein junction.  PMID:21599752

  16. [Medical and relieving activities initiated by Guangdong Charity Organizations in the late Qing Dynasty].

    PubMed

    Lai, Wen; Li, Yongchen

    2007-07-01

    The late Qing Dynasty had witnessed the peak of epidemic outbreak in the southern part of China. However, that is also the time when the non-governmental charity activities in Guangdong grew into prosperity. As is shown in the 1909 archives of China's association activities, Guangdong charity organizations at the time played an active role in medical and relieving activities, by using flexible and various means of relief with extensive beneficiaries. Some of those medical activities are beyond the category of mere charity relief. The ideology advocated by the founders and the practitioners of such charity organizations constructed the most fundamental local humanity relief and health care system, as well as their painstaking efforts in bringing these ideas into reality, have contributed significantly to the local stability and harmony of the society, to the cultivation of public welfare awareness in the social and medical sectors of modern Guangdong society, and to the development of Guangdong's public sanitary system. Moreover, they have brought noteworthy influence on the continuation of traditional Chinese medicine and the advancement of the local regional medical studies. PMID:18453204

  17. Efficacy of Trimetazidine Dihydrochloride for Relieving Chronic Tinnitus: A Randomized Double-Blind Study

    PubMed Central

    Kumral, Tolgar Lütfi; Yıldırım, Güven; Berkiten, Güler; Saltürk, Ziya; Ataç, Enes; Atar, Yavuz; Uyar, Yavuz

    2016-01-01

    Objectives: To evaluate the efficacy of trimetazidine dihydrochloride as a treatment for chronic tinnitus. Methods: A total of 97 chronic tinnitus patients were evaluated in this randomized, prospective, double-blind, placebo-controlled trial. After assessing for eligibility, 82 patients were randomly assigned into placebo or trimetazidine groups according to the medication. The trimetazidine group received 20×3 mg/day per oral trimetazidine dihydrochloride and the placebo group received 20×3 mg/day per oral placebo for 3 months. Tinnitus handicap inventory (THI), visual analogue scale (VAS) questionnaires and audiometric results were used to determine the effectiveness of trimetazidine treatment. Results: The study group comprised 82 tinnitus subjects, 42 (51%) of whom received trimetazidine dihydrochloride and 40 (49%) who received placebo. There was no significant difference between placebo and trimetazidine groups in THI grade and VAS (both pre- and posttreatment scores) (P>0.05) and no significant improvement was observed in subjective loudness score in either group (P>0.05). Additionally there was no significant difference between groups in pre- and posttreatment pure tone hearing thresholds at all measured frequencies (P>0.05). Conclusion: Trimetazidine dihydrochloride therapy was ineffective for relieving chronic tinnitus. PMID:27230273

  18. Percutaneous vertebroplasty immediately relieves pain of osteoporotic vertebral compression fractures and prevents prolonged immobilization of patients.

    PubMed

    Kobayashi, Kiyokazu; Shimoyama, Keiji; Nakamura, Keiya; Murata, Kiyoshi

    2005-02-01

    To assess the immediate efficacy of percutaneous vertebroplasty (PVP) in relief of pain and improving mobility of patients with vertebral compression fractures (VCF) secondary to osteoporosis, 205 cases (175 patients) underwent 250 percutaneous injections of polymethylmethacrylate (PMMA; unilateral, 247 levels; bilateral, 3 levels) into vertebrae under CT and fluoroscopic guidance for 34 months. Patients were prospectively asked to quantify their pain on a visual analog scale (VAS) before and a day after PVP. The interval to mobilization was recorded in those who were immobilized because of pain and/or bed-rest therapy (115 cases). PVP was technically successful in all patients, with three cases of minimal complications. The mean VAS score available for 196 cases was improved from 7.22+/-1.89 (range, 3-10) to 2.07+/-1.19 (range, 0-10) by PVP. Ninety-four of 115 immobilized cases (81.7%) were mobile by 24 h after PVP, and the mean value was 1.9+/-2.8 days. The incidence of recurrent and new fractures was 15.6% in 4-25 months (mean, 15.3 months). PVP is a safe and effective treatment for relieving the pain associated with osteoporotic VCF and strengthening the vertebrae, avoiding refractures. This therapy leads to early mobilization and avoidance of the dangers of conservative therapy of bed-rest. PMID:15662480

  19. Update on nonpharmacologic approaches to relieve labor pain and prevent suffering.

    PubMed

    Simkin, Penny; Bolding, April

    2004-01-01

    The control of labor pain and prevention of suffering are major concerns of clinicians and their clients. Nonpharmacologic approaches toward these goals are consistent with midwifery management and the choices of many women. We undertook a literature search of scientific articles cataloged in CINAHL, PUBMED, the Cochrane Library, and AMED databases relating to the effectiveness of 13 non-pharmacologic methods used to relieve pain and reduce suffering in labor. Suffering, which is different from pain, is not an outcome that is usually measured after childbirth. We assumed that suffering is unlikely if indicators of satisfaction were positive after childbirth. Adequate evidence of benefit in reducing pain exists for continuous labor support, baths, intradermal water blocks, and maternal movement and positioning. Acupuncture, massage, transcutaneous electrical nerve stimulation, and hypnosis are promising, but they require further study. The effectiveness of childbirth education, relaxation and breathing, heat and cold, acupressure, hypnosis, aromatherapy, music, and audioanalgesia are either inadequately studied or findings are too variable to draw conclusions on effectiveness. All the methods studied had evidence of widespread satisfaction among a majority of users. PMID:15544978

  20. Enteral sesame oil therapeutically relieves disease severity in rat experimental osteoarthritis

    PubMed Central

    Hsu, Dur-Zong; Chu, Pei-Yi; Jou, I-Ming

    2016-01-01

    Background Osteoarthritis (OA) is the most common cause of joint pain, affecting approximately 15% of the population. Recent studies indicate that quadriceps muscle weakness is directly involved in the pathogenesis of OA-associated joint pain. Oxidative stress plays an important role in skeletal muscle dysfunction. Sesame oil is a natural product with excellent antioxidative property. However, whether sesame oil can decrease OA-induced joint pain has never been investigated. Objective The aim of the present study was to examine the effect of sesame oil on OA-induced joint pain in rats. Design OA-associated joint pain in rats was induced by medial meniscal transection in rats. Sesame oil (0, 1, 2, or 4 ml/kg/day, orally) was given to rats 7 days after OA induction, while the parameters were determined 7 days after sesame oil administration. Results Daily sesame oil treatment for 7 days significantly decreased OA-associated joint pain. Sesame oil decreased muscular interleukin-6 and increased citrate synthase activity and myosin heavy chain IIa mRNA expression. Furthermore, sesame oil decreased muscular lipid peroxidation, nuclear Nrf2 protein expression, and reactive oxygen species generations as well as increased glutathione production and glutathione peroxidase activity in OA rats. Conclusions Sesame oil may relieve OA-associated joint pain by inhibiting quadriceps muscular oxidative stress, at least partially, in rats. PMID:27032670