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Sample records for dna relieves torsional

  1. Transport of torsional stress in DNA

    PubMed Central

    Nelson, Philip

    1999-01-01

    It is well known that transcription can induce torsional stress in DNA, affecting the activity of nearby genes or even inducing structural transitions in the DNA duplex. It has long been assumed that the generation of significant torsional stress requires the DNA to be anchored, forming a limited topological domain, because otherwise it would spin almost freely about its axis. Previous estimates of the rotational drag have, however, neglected the role of small natural bends in the helix backbone. We show how these bends can increase the drag several thousandfold relative to prior estimates, allowing significant torsional stress even in linear unanchored DNA. The model helps explain several puzzling experimental results on structural transitions induced by transcription of DNA. PMID:10588707

  2. Transport of Torsional Stress in DNA

    NASA Astrophysics Data System (ADS)

    Nelson, Philip

    1999-12-01

    It is well known that transcription can induce torsional stress in DNA, affecting the activity of nearby genes or even inducing structural transitions in the DNA duplex. It has long been assumed that the generation of significant torsional stress requires the DNA to be anchored, forming a limited topological domain, because otherwise it would spin almost freely about its axis. Previous estimates of the rotational drag have, however, neglected the role of small natural bonds in the helix backbone. We show how these bends can increase the drag several thousandfold relative to prior estimates, allowing significant torsional stress even in linear unanchored DNA. The model helps explain several puzzling experimental results on structural transitions induced by transcription of DNA.

  3. 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.

  4. Composite model for DNA torsion dynamics.

    PubMed

    Cadoni, Mariano; De Leo, Roberto; Gaeta, Giuseppe

    2007-02-01

    DNA torsion dynamics is essential in the transcription process; a simple model for it, in reasonable agreement with experimental observations, has been proposed by Yakushevich (Y) and developed by several authors; in this, the nucleotides (the DNA subunits made of a sugar-phosphate group and the attached nitrogen base) are described by a single degree of freedom. In this paper we propose and investigate, both analytically and numerically, a "composite" version of the Y model, in which the sugar-phosphate group and the base are described by separate degrees of freedom. The model proposed here contains as a particular case the Y model and shares with it many features and results, but represents an improvement from both the conceptual and the phenomenological point of view. It provides a more realistic description of DNA and possibly a justification for the use of models which consider the DNA chain as uniform. It shows that the existence of solitons is a generic feature of the underlying nonlinear dynamics and is to a large extent independent of the detailed modeling of DNA. The model we consider supports solitonic solutions, qualitatively and quantitatively very similar to the Y solitons, in a fully realistic range of all the physical parameters characterizing the DNA.

  5. Doxorubicin, DNA torsion, and chromatin dynamics

    PubMed Central

    Yang, Fan; Teves, Sheila S.; Kemp, Christopher J.; Henikoff, Steven

    2014-01-01

    Doxorubicin is one of the most important anti-cancer chemotherapeutic drugs, being widely used for the treatment of solid tumors and acute leukemias. The action of doxorubicin and other anthracycline drugs has been intensively investigated during the last several decades, but the mechanisms that have been proposed for cell killing remain disparate and controversial. In this review, we examine the proposed models for doxorubicin action from the perspective of the chromatin landscape, which is altered in many types of cancer due to recurrent mutations in chromatin modifiers. We highlight recent evidence for effects of anthracyclines on DNA torsion and chromatin dynamics that may underlie basic mechanisms of doxorubicin-mediated cell death and suggest new therapeutic strategies for cancer treatment. PMID:24361676

  6. Localized Torsional Tension in the DNA of Human Cells

    NASA Astrophysics Data System (ADS)

    Ljungman, Mats; Hanawalt, Philip C.

    1992-07-01

    Torsional tension in DNA may be both a prerequisite for the efficient initiation of transcription and a consequence of the transcription process itself with the generation of positive torsional tension in front of the RNA polymerase and negative torsional tension behind it. To examine torsional tension in specific regions of genomic DNA in vivo, we developed an assay using photoactivated psoralen as a probe for unconstrained DNA superhelicity and x-rays as a means to relax DNA. Psoralen intercalates more readily into DNA underwound by negative torsional tension than into relaxed DNA, and it can form interstrand DNA cross-links upon UVA irradiation. By comparing the amount of psoralen-induced DNA cross-links in cells irradiated with x-rays either before or after the psoralen treatment, we examined the topological state of the DNA in specific regions of the genome in cultured human 6A3 cells. We found that although no net torsional tension was detected in the bulk of the genome, localized tension was prominent in the DNA of two active genes. Negative torsional tension was found in the 5' end of the amplified dihydrofolate reductase gene and in a region near the 5' end of the 45S rRNA transcription unit, whereas a low level of positive torsional tension was found in a region near the 3' end of the dihydrofolate reductase gene. These results document an intragenomic heterogeneity of DNA torsional tension and lend support to the twin supercoiled domain model for transcription in the genome of intact human cells.

  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. Impact of DNA Twist Accumulation on Progressive Helical Wrapping of Torsionally Constrained DNA

    NASA Astrophysics Data System (ADS)

    Li, Wei; Wang, Peng-Ye; Yan, Jie; Li, Ming

    2012-11-01

    DNA wrapping is an important mechanism for chromosomal DNA packaging in cells and viruses. Previous studies of DNA wrapping have been performed mostly on torsionally unconstrained DNA, while in vivo DNA is often under torsional constraint. In this study, we extend a previously proposed theoretical model for wrapping of torsionally unconstrained DNA to a new model including the contribution of DNA twist energy, which influences DNA wrapping drastically. In particular, due to accumulation of twist energy during DNA wrapping, it predicts a finite amount of DNA that can be wrapped on a helical spool. The predictions of the new model are tested by single-molecule study of DNA wrapping under torsional constraint using magnetic tweezers. The theoretical predictions and the experimental results are consistent with each other and their implications are discussed.

  9. Magnetic torque tweezers: measuring torsional stiffness in DNA and RecA-DNA filaments.

    PubMed

    Lipfert, Jan; Kerssemakers, Jacob W J; Jager, Tessa; Dekker, Nynke H

    2010-12-01

    We introduce magnetic torque tweezers, which enable direct single-molecule measurements of torque. Our measurements of the effective torsional stiffness C of dsDNA indicated a substantial force dependence, with C = approximately 40 nm at low forces up to C = approximately 100 nm at high forces. The initial torsional stiffness of RecA filaments was nearly twofold larger than that for dsDNA, yet at moderate torques further build-up of torsional strain was prevented.

  10. 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.

  11. Extension of torsionally stressed DNA by external force.

    PubMed Central

    Vologodskii, A V; Marko, J F

    1997-01-01

    Metropolis Monte Carlo simulation was used to study the elasticity of torsionally stressed double-helical DNA. Equilibrium distributions of DNA conformations for different values of linking deficit, external force, and ionic conditions were simulated using the discrete wormlike chain model. Ionic conditions were specified in terms of DNA effective diameter, i.e., hard-core radius of the model chain. The simulations show that entropic elasticity of the double helix depends on how much it is twisted. For low amounts of twisting (less than about one turn per twist persistence length) the force versus extension is nearly the same as in the completely torsionally relaxed case. For more twisting than this, the molecule starts to supercoil, and there is an increase in the force needed to realize a given extension. For sufficiently large amounts of twist, the entire chain is plectonemically supercoiled at low extensions; a finite force must be applied to obtain any extension at all in this regime. The simulation results agree well with the results of recent micromanipulation experiments. PMID:9199777

  12. Nonlinear effects in the torsional adjustment of interacting DNA

    NASA Astrophysics Data System (ADS)

    Kornyshev, A. A.; Wynveen, A.

    2004-04-01

    DNA molecules in solution, having negatively charged phosphates and countercations readsorbed on its surface, possess a distinct charge separation motif to interact electrostatically. If their double-helical structure were ideal, duplexes in parallel juxtaposition could choose azimuthal alignment providing attraction, or at least a reduction of repulsion, between them. But duplexes are not perfect staircases and the distortions of their helical structure correlate with their base pair texts. If the patterns of distortions on the opposing molecules are uncorrelated, the mismatch will accumulate as a random walk and attraction vanishes. Based on this idea, a model of recognition of homologous sequences has been proposed [A. A. Kornyshev and S. Leikin, Phys. Rev. Lett. 86, 3666 (2001)]. But DNA has torsional elasticity. How will this help to relax a mismatch between the charge distributions on two nonhomologous DNA’s? In the same work, the solution of this problem has been mapped onto a frustrated sine Gordon equation in a nonlocal random field (where the latter represents a pattern of twist angle distortions on the opposing molecules), but the results had been obtained in the limit of torsionally rigid molecules. In the present paper, by solving this equation numerically, we find a strongly nonlinear relaxation mechanism which utilizes static kink-soliton modes triggered by the “random field.” In the range of parameters where the solitons do not emerge, we find good agreement with the results of a variational study [A. G. Cherstvy, A. A. Kornyshev, and S. Leikin, J. Phys. Chem. B (to be published)]. We reproduce the first-order transitions in the interaxial separation dependence, but detect also second-order or weak first-order transitions for shorter duplexes. The recognition energy between two nonhomologous DNA sequences is calculated as a function of interaxial separation and the length of juxtaposition. The soliton-caused kinky length dependence is

  13. Torsionally constrained DNA for single-molecule assays: an efficient, ligation-free method

    PubMed Central

    Paik, D. Hern; Roskens, Violet A.; Perkins, Thomas T.

    2013-01-01

    Controlled twisting of individual, double-stranded DNA molecules provides a unique method to investigate the enzymes that alter DNA topology. Such twisting requires a single DNA molecule to be torsionally constrained. This constraint is achieved by anchoring the opposite ends of the DNA to two separate surfaces via multiple bonds. The traditional protocol for making such DNA involves a three-way ligation followed by gel purification, a laborious process that often leads to low yield both in the amount of DNA and the fraction of molecules that is torsionally constrained. We developed a simple ligation-free procedure for making torsionally constrained DNA via polymerase chain reaction (PCR). This PCR protocol used two ‘megaprimers’, 400-base-pair long double-stranded DNA that were labelled with either biotin or digoxigenin. We obtained a relatively high yield of gel-purified DNA (∼500 ng/100 µl of PCR reaction). The final construct in this PCR-based method contains only one labelled strand in contrast to the traditional construct in which both strands of the DNA are labelled. Nonetheless, we achieved a high yield (84%) of torsionally constrained DNA when measured using an optical-trap-based DNA-overstretching assay. This protocol significantly simplifies the application and adoption of torsionally constrained assays to a wide range of single-molecule systems. PMID:23935118

  14. Torsionally constrained DNA for single-molecule assays: an efficient, ligation-free method.

    PubMed

    Paik, D Hern; Roskens, Violet A; Perkins, Thomas T

    2013-10-01

    Controlled twisting of individual, double-stranded DNA molecules provides a unique method to investigate the enzymes that alter DNA topology. Such twisting requires a single DNA molecule to be torsionally constrained. This constraint is achieved by anchoring the opposite ends of the DNA to two separate surfaces via multiple bonds. The traditional protocol for making such DNA involves a three-way ligation followed by gel purification, a laborious process that often leads to low yield both in the amount of DNA and the fraction of molecules that is torsionally constrained. We developed a simple ligation-free procedure for making torsionally constrained DNA via polymerase chain reaction (PCR). This PCR protocol used two 'megaprimers', 400-base-pair long double-stranded DNA that were labelled with either biotin or digoxigenin. We obtained a relatively high yield of gel-purified DNA (∼500 ng/100 µl of PCR reaction). The final construct in this PCR-based method contains only one labelled strand in contrast to the traditional construct in which both strands of the DNA are labelled. Nonetheless, we achieved a high yield (84%) of torsionally constrained DNA when measured using an optical-trap-based DNA-overstretching assay. This protocol significantly simplifies the application and adoption of torsionally constrained assays to a wide range of single-molecule systems.

  15. 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.

  16. Fluorescence anisotropy of DNA/DAPI complex: torsional dynamics and geometry of the complex.

    PubMed Central

    Barcellona, M L; Gratton, E

    1996-01-01

    Fluorescence depolarization of synthetic polydeoxynucleotide/4'-6-diamidino-2-phenylindole dihydrochloride complexes has been investigated as a function of dye/polymer coverage. At low coverage, fluorescence depolarization is due to local torsional motions of the DNA segment where the dye resides. At relatively high coverage, fluorescence depolarization is dominated by energy transfer to other dye molecules along the DNA. The extent of the observed depolarization due to torsional motion depends on the angle the dye molecule forms with the DNA helical axis. A large torsional motion and a small angle produce the same depolarization as a small torsional motion and a large projection angle. Furthermore, the extent of transfer critically depends on the relative orientation of dye molecules along the DNA. The effect of multiple transfer is examined using a Monte Carlo approach. The measurement of depolarization with transfer, at high coverage, allows determination of the dye orientation about the DNA helical axis. The value of the torsional spring constant is then determined, at very low coverage, for few selected polydeoxynucleotides. Images FIGURE 3 PMID:9172758

  17. Probing the salt dependence of the torsional stiffness of DNA by multiplexed magnetic torque tweezers

    PubMed Central

    Kriegel, Franziska; Ermann, Niklas; Forbes, Ruaridh; Dulin, David; Dekker, Nynke H.

    2017-01-01

    Abstract The mechanical properties of DNA fundamentally constrain and enable the storage and transmission of genetic information and its use in DNA nanotechnology. Many properties of DNA depend on the ionic environment due to its highly charged backbone. In particular, both theoretical analyses and direct single-molecule experiments have shown its bending stiffness to depend on salt concentration. In contrast, the salt-dependence of the twist stiffness of DNA is much less explored. Here, we employ optimized multiplexed magnetic torque tweezers to study the torsional stiffness of DNA under varying salt conditions as a function of stretching force. At low forces (<3 pN), the effective torsional stiffness is ∼10% smaller for high salt conditions (500 mM NaCl or 10 mM MgCl2) compared to lower salt concentrations (20 mM NaCl and 100 mM NaCl). These differences, however, can be accounted for by taking into account the known salt dependence of the bending stiffness. In addition, the measured high-force (6.5 pN) torsional stiffness values of C = 103 ± 4 nm are identical, within experimental errors, for all tested salt concentration, suggesting that the intrinsic torsional stiffness of DNA does not depend on salt. PMID:28460037

  18. The dynamic response of upstream DNA to transcription-generated torsional stress.

    PubMed

    Kouzine, Fedor; Liu, Juhong; Sanford, Suzanne; Chung, Hye-Jung; Levens, David

    2004-11-01

    The torsional stress caused by counter-rotation of the transcription machinery and template generates supercoils in a closed topological domain, but has been presumed to be too short-lived to be significant in an open domain. This report shows that transcribing RNA polymerases dynamically sustain sufficient torsion to perturb DNA structure even on linear templates. Assays to capture and measure transcriptionally generated torque and to trap short-lived perturbations in DNA structure and conformation showed that the transient forces upstream of active promoters are large enough to drive the supercoil-sensitive far upstream element (FUSE) of the human c-myc into single-stranded DNA. An alternative non-B conformation of FUSE found in stably supercoiled DNA is not accessible dynamically. These results demonstrate that dynamic disturbance of DNA structure provides a real-time measure of ongoing genetic activity.

  19. Single-Molecule Study of the DNA Denaturation Phase Transition in the Force-Torsion Space

    NASA Astrophysics Data System (ADS)

    Salerno, D.; Tempestini, A.; Mai, I.; Brogioli, D.; Ziano, R.; Cassina, V.; Mantegazza, F.

    2012-09-01

    We use the “magnetic tweezers” technique to show the structural transitions that the DNA undergoes in the force-torsion space. In particular, we focus on the regions corresponding to negative supercoiling. These regions are characterized by the formation of the so-called denaturation bubbles, which play an essential role in the replication and transcription of DNA. We experimentally map the region of the force-torsion space where the denaturation takes place. We observe that large fluctuations in DNA extension occur at one of the boundaries of this region, i.e., when the formation of denaturation bubbles and of plectonemes compete. To describe the experiments, we introduce a suitable extension of the classical model. The model correctly describes the position of the denaturation regions, the transition boundaries, and the measured values of the DNA extension fluctuations.

  20. 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

  1. Torsional regulation of hRPA-induced unwinding of double-stranded DNA.

    PubMed

    De Vlaminck, Iwijn; Vidic, Iztok; van Loenhout, Marijn T J; Kanaar, Roland; Lebbink, Joyce H G; Dekker, Cees

    2010-07-01

    All cellular single-stranded (ss) DNA is rapidly bound and stabilized by single stranded DNA-binding proteins (SSBs). Replication protein A, the main eukaryotic SSB, is able to unwind double-stranded (ds) DNA by binding and stabilizing transiently forming bubbles of ssDNA. Here, we study the dynamics of human RPA (hRPA) activity on topologically constrained dsDNA with single-molecule magnetic tweezers. We find that the hRPA unwinding rate is exponentially dependent on torsion present in the DNA. The unwinding reaction is self-limiting, ultimately removing the driving torsional stress. The process can easily be reverted: release of tension or the application of a rewinding torque leads to protein dissociation and helix rewinding. Based on the force and salt dependence of the in vitro kinetics we anticipate that the unwinding reaction occurs frequently in vivo. We propose that the hRPA unwinding reaction serves to protect and stabilize the dsDNA when it is structurally destabilized by mechanical stresses.

  2. Toward Improved Description of DNA Backbone: Revisiting Epsilon and Zeta Torsion Force Field Parameters

    PubMed Central

    Zgarbová, Marie; Luque, F. Javier; Šponer, Jiří; Cheatham, Thomas E.; Otyepka, Michal; Jurečka, Petr

    2013-01-01

    We present a refinement of the backbone torsion parameters ε and ζ of the Cornell et al. AMBER force field for DNA simulations. The new parameters, denoted as εζOL1, were derived from quantum-mechanical calculations with inclusion of conformation-dependent solvation effects according to the recently reported methodology (J. Chem. Theory Comput. 2012, 7(9), 2886-2902). The performance of the refined parameters was analyzed by means of extended molecular dynamics (MD) simulations for several representative systems. The results showed that the εζOL1 refinement improves the backbone description of B-DNA double helices and G-DNA stem. In B-DNA simulations, we observed an average increase of the helical twist and narrowing of the major groove, thus achieving better agreement with X-ray and solution NMR data. The balance between populations of BI and BII backbone substates was shifted towards the BII state, in better agreement with ensemble-refined solution experimental results. Furthermore, the refined parameters decreased the backbone RMS deviations in B-DNA MD simulations. In the antiparallel guanine quadruplex (G-DNA) the εζOL1 modification improved the description of non-canonical α/γ backbone substates, which were shown to be coupled to the ε/ζ torsion potential. Thus, the refinement is suggested as a possible alternative to the current ε/ζ torsion potential, which may enable more accurate modeling of nucleic acids. However, long-term testing is recommended before its routine application in DNA simulations. PMID:24058302

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

    PubMed

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

    2014-01-17

    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.

  4. 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.

  5. FACT is a sensor of DNA torsional stress in eukaryotic cells.

    PubMed

    Safina, Alfiya; Cheney, Peter; Pal, Mahadeb; Brodsky, Leonid; Ivanov, Alexander; Kirsanov, Kirill; Lesovaya, Ekaterina; Naberezhnov, Denis; Nesher, Elimelech; Koman, Igor; Wang, Dan; Wang, Jianming; Yakubovskaya, Marianna; Winkler, Duane; Gurova, Katerina

    2017-02-28

    Transitions of B-DNA to alternative DNA structures (ADS) can be triggered by negative torsional strain, which occurs during replication and transcription, and may lead to genomic instability. However, how ADS are recognized in cells is unclear. We found that the binding of candidate anticancer drug, curaxin, to cellular DNA results in uncoiling of nucleosomal DNA, accumulation of negative supercoiling and conversion of multiple regions of genomic DNA into left-handed Z-form. Histone chaperone FACT binds rapidly to the same regions via the SSRP1 subunit in curaxin-treated cells. In vitro binding of purified SSRP1 or its isolated CID domain to a methylated DNA fragment containing alternating purine/pyrimidines, which is prone to Z-DNA transition, is much stronger than to other types of DNA. We propose that FACT can recognize and bind Z-DNA or DNA in transition from a B to Z form. Binding of FACT to these genomic regions triggers a p53 response. Furthermore, FACT has been shown to bind to other types of ADS through a different structural domain, which also leads to p53 activation. Thus, we propose that FACT acts as a sensor of ADS formation in cells. Recognition of ADS by FACT followed by a p53 response may explain the role of FACT in DNA damage prevention. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  6. Restrained torsional dynamics of nuclear DNA in living proliferative mammalian cells.

    PubMed Central

    Tramier, M; Kemnitz, K; Durieux, C; Coppey, J; Denjean, P; Pansu, R B; Coppey-Moisan, M

    2000-01-01

    Physical parameters, describing the state of chromatinized DNA in living mammalian cells, were revealed by in situ fluorescence dynamic properties of ethidium in its free and intercalated states. The lifetimes and anisotropy decays of this cationic chromophore were measured within the nuclear domain, by using the ultra-sensitive time-correlated single-photon counting technique, confocal microscopy, and ultra-low probe concentrations. We found that, in living cells: 1) free ethidium molecules equilibrate between extracellular milieu and nucleus, demonstrating that the cation is naturally transported into the nucleus; 2) the intercalation of ethidium into chromatinized DNA is strongly inhibited, with relaxation of the inhibition after mild (digitonin) cell treatment; 3) intercalation sites are likely to be located in chromatin DNA; and 4) the fluorescence anisotropy relaxation of intercalated molecules is very slow. The combination of fluorescence kinetic and fluorescence anisotropy dynamics indicates that the torsional dynamics of nuclear DNA is highly restrained in living cells. PMID:10777758

  7. Force and twist dependence of RepC nicking activity on torsionally-constrained DNA molecules

    PubMed Central

    Pastrana, Cesar L.; Carrasco, Carolina; Akhtar, Parvez; Leuba, Sanford H.; Khan, Saleem A.; Moreno-Herrero, Fernando

    2016-01-01

    Many bacterial plasmids replicate by an asymmetric rolling-circle mechanism that requires sequence-specific recognition for initiation, nicking of one of the template DNA strands and unwinding of the duplex prior to subsequent leading strand DNA synthesis. Nicking is performed by a replication-initiation protein (Rep) that directly binds to the plasmid double-stranded origin and remains covalently bound to its substrate 5′-end via a phosphotyrosine linkage. It has been proposed that the inverted DNA sequences at the nick site form a cruciform structure that facilitates DNA cleavage. However, the role of Rep proteins in the formation of this cruciform and the implication for its nicking and religation functions is unclear. Here, we have used magnetic tweezers to directly measure the DNA nicking and religation activities of RepC, the replication initiator protein of plasmid pT181, in plasmid sized and torsionally-constrained linear DNA molecules. Nicking by RepC occurred only in negatively supercoiled DNA and was force- and twist-dependent. Comparison with a type IB topoisomerase in similar experiments highlighted a relatively inefficient religation activity of RepC. Based on the structural modeling of RepC and on our experimental evidence, we propose a model where RepC nicking activity is passive and dependent upon the supercoiling degree of the DNA substrate. PMID:27488190

  8. 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.

  9. 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

    2016-06-02

    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.

  10. 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

  11. 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.

  12. Crossover-site sequence and DNA torsional stress control strand interchanges by the Bxb1 site-specific serine recombinase

    PubMed Central

    Keenholtz, Ross A.; Grindley, Nigel D.F.; Hatfull, Graham F.; Marko, John F.

    2016-01-01

    DNA segment exchange by site-specific serine recombinases (SRs) is thought to proceed by rigid-body rotation of the two halves of the synaptic complex, following the cleavages that create the two pairs of exchangeable ends. It remains unresolved how the amount of rotation occurring between cleavage and religation is controlled. We report single-DNA experiments for Bxb1 integrase, a model SR, where dynamics of individual synapses were observed, using relaxation of supercoiling to report on cleavage and rotation events. Relaxation events often consist of multiple rotations, with the number of rotations per relaxation event and rotation velocity sensitive to DNA sequence at the center of the recombination crossover site, torsional stress and salt concentration. Bulk and single-DNA experiments indicate that the thermodynamic stability of the annealed, but cleaved, crossover sites controls ligation efficiency of recombinant and parental synaptic complexes, regulating the number of rotations during a breakage-religation cycle. The outcome is consistent with a ‘controlled rotation’ model analogous to that observed for type IB topoisomerases, with religation probability varying in accord with DNA base-pairing free energies at the crossover site. Significantly, we find no evidence for a special regulatory mechanism favoring ligation and product release after a single 180° rotation. PMID:27550179

  13. Testicular Torsion

    MedlinePlus

    ... Journal of Urology. 2011;185:2469. Hittelman AB. Neonatal testicular torsion. http://www.uptodate.com/home. Accessed ... 16, 2015. Snyder HM, et al. In utero/neonatal torsion: Observation versus prompt exploration. Journal of Urology. ...

  14. 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

  15. Ursolic Acid-Regulated Energy Metabolism—Reliever or Propeller of Ultraviolet-Induced Oxidative Stress and DNA Damage?

    PubMed Central

    Lee, Yuan-Hao; Sun, Youping; Glickman, Randolph D.

    2014-01-01

    Ultraviolet (UV) light is a leading cause of diseases, such as skin cancers and cataracts. A main process mediating UV-induced pathogenesis is the production of reactive oxygen species (ROS). Excessive ROS levels induce the formation of DNA adducts (e.g., pyrimidine dimers) and result in stalled DNA replication forks. In addition, ROS promotes phosphorylation of tyrosine kinase-coupled hormone receptors and alters downstream energy metabolism. With respect to the risk of UV-induced photocarcinogenesis and photodamage, the antitumoral and antioxidant functions of natural compounds become important for reducing UV-induced adverse effects. One important question in the field is what determines the differential sensitivity of various types of cells to UV light and how exogenous molecules, such as phytochemicals, protect normal cells from UV-inflicted damage while potentiating tumor cell death, presumably via interaction with intracellular target molecules and signaling pathways. Several endogenous molecules have emerged as possible players mediating UV-triggered DNA damage responses. Specifically, UV activates the PIKK (phosphatidylinositol 3-kinase-related kinase) family members, which include DNA-PKcs, ATM (ataxia telangiectasia mutated) and mTOR (mammalian target of rapamycin), whose signaling can be affected by energy metabolism; however, it remains unclear to what extent the activation of hormone receptors regulates PIKKs and whether this crosstalk occurs in all types of cells in response to UV. This review focuses on proteomic descriptions of the relationships between cellular photosensitivity and the phenotypic expression of the insulin/insulin-like growth receptor. It covers the cAMP-dependent pathways, which have recently been shown to regulate the DNA repair machinery through interactions with the PIKK family members. Finally, this review provides a strategic illustration of how UV-induced mitogenic activity is modulated by the insulin sensitizer, ursolic

  16. Twist-Bend Coupling and the Torsional Response of Double-Stranded DNA

    NASA Astrophysics Data System (ADS)

    Nomidis, Stefanos K.; Kriegel, Franziska; Vanderlinden, Willem; Lipfert, Jan; Carlon, Enrico

    2017-05-01

    Recent magnetic tweezers experiments have reported systematic deviations of the twist response of double-stranded DNA from the predictions of the twistable wormlike chain model. Here we show, by means of analytical results and computer simulations, that these discrepancies can be resolved if a coupling between twist and bend is introduced. We obtain an estimate of 40 ±10 nm for the twist-bend coupling constant. Our simulations are in good agreement with high-resolution, magnetic-tweezers torque data. Although the existence of twist-bend coupling was predicted long ago [J. Marko and E. Siggia, Macromolecules 27, 981 (1994), 10.1021/ma00082a015], its effects on the mechanical properties of DNA have been so far largely unexplored. We expect that this coupling plays an important role in several aspects of DNA statics and dynamics.

  17. Testicular torsion.

    PubMed

    Ringdahl, Erika; Teague, Lynn

    2006-11-15

    Each year, testicular torsion affects one in 4,000 males younger than 25 years. Early diagnosis and definitive management are the keys to avoid testicular loss. All prepubertal and young adult males with acute scrotal pain should be considered to have testicular torsion until proven otherwise. The finding of an ipsilateral absent cremasteric reflex is the most accurate sign of testicular torsion. Torsion of the appendix testis is more common in children than testicular torsion and may be diagnosed by the "blue dot sign" (i.e., tender nodule with blue discoloration on the upper pole of the testis). Epididymitis/orchitis is much less common in the prepubertal male, and the diagnosis should be made with caution in this age group. Doppler ultrasonography may be needed for definitive diagnosis; radionuclide scintigraphy is an alternative that may be more accurate but should be ordered only if it can be performed without delay. Diagnosis of testicular torsion is based on the finding of decreased or absent blood flow on the ipsilateral side. Treatment involves rapid restoration of blood flow to the affected testis. The optimal time frame is less than six hours after the onset of symptoms. Manual detorsion by external rotation of the testis can be successful, but restoration of blood flow must be confirmed following the maneuver. Surgical exploration provides definitive treatment for the affected testis by orchiopexy and allows for prophylactic orchiopexy of the contralateral testis. Surgical treatment of torsion of the appendix testis is not mandatory but hastens recovery.

  18. SENP7 Potentiates cGAS Activation by Relieving SUMO-Mediated Inhibition of Cytosolic DNA Sensing

    PubMed Central

    Cui, Ye; Yu, Huansha; Zheng, Xin; Peng, Rui; Wang, Qiang; Zhou, Yi; Wang, Rui; Wang, Jiehua; Qu, Bo; Shen, Nan; Guo, Qiang; Liu, Xing; Wang, Chen

    2017-01-01

    Cyclic GMP-AMP (cGAMP) synthase (cGAS, a.k.a. MB21D1), a cytosolic DNA sensor, catalyzes formation of the second messenger 2’3’-cGAMP that activates the stimulator of interferon genes (STING) signaling. How the cGAS activity is modulated remains largely unknown. Here, we demonstrate that sentrin/SUMO-specific protease 7 (SENP7) interacted with and potentiated cGAS activation. The small ubiquitin-like modifier (SUMO) was conjugated onto the lysine residues 335, 372 and 382 of cGAS, which suppressed its DNA-binding, oligomerization and nucleotidyl-transferase activities. SENP7 reversed this inhibition via catalyzing the cGAS de-SUMOylation. Consistently, silencing of SENP7 markedly impaired the IRF3-responsive gene expression induced by cGAS-STING axis. SENP7-knockdown mice were more susceptible to herpes simplex virus 1 (HSV-1) infection. SENP7 was significantly up-regulated in patients with SLE. Our study highlights the temporal modulation of the cGAS activity via dynamic SUMOylation, uncovering a novel mechanism for fine-tuning the STING signaling in innate immunity. PMID:28095500

  19. 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.

  20. Terminal differentiation of cardiac and skeletal myocytes induces permissivity to AAV transduction by relieving inhibition imposed by DNA damage response proteins.

    PubMed

    Lovric, Jasmina; Mano, Miguel; Zentilin, Lorena; Eulalio, Ana; Zacchigna, Serena; Giacca, Mauro

    2012-11-01

    Gene therapy vectors based on the adeno-associated virus (AAV) are extremely efficient for gene transfer into post-mitotic cells of heart, muscle, brain, and retina. The reason for their exquisite tropism for these cells has long remained elusive. Here, we show that upon terminal differentiation, cardiac and skeletal myocytes downregulate proteins of the DNA damage response (DDR) and that this markedly induces permissivity to AAV transduction. We observed that expression of members of the MRN complex (Mre11, Rad50, Nbs1), which bind the incoming AAV genomes, faded in cardiomyocytes at ~2 weeks after birth, as well as upon myoblast differentiation in vitro; in both cases, withdrawal of the cells from the cell cycle coincided with increased AAV permissivity. Treatment of proliferating cells with short-interfering RNAs (siRNAs) against the MRN proteins, or with microRNA-24, which is normally upregulated upon terminal differentiation and negatively controls the Nbs1 levels, significantly increased permissivity to AAV transduction. Consistently, delivery of these small RNAs to the juvenile liver concomitant with AAV markedly improved in vivo hepatocyte transduction. Collectively, these findings support the conclusion that cellular DDR proteins inhibit AAV transduction and that terminal cell differentiation relieves this restriction.

  1. 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

  2. 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.

  3. 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.

  4. Pediatric Testicular Torsion.

    PubMed

    Bowlin, Paul R; Gatti, John M; Murphy, J Patrick

    2017-02-01

    The pediatric patient presenting with acute scrotal pain requires prompt evaluation and management given the likelihood of testicular torsion as the underlying cause. Although other diagnoses can present with acute testicular pain, it is important to recognize the possibility of testicular torsion because the best chance of testicular preservation occurs with expeditious management. When testicular torsion is suspected, prompt surgical exploration is warranted. A delay in surgical management should not occur in an effort to obtain confirmatory imaging. When torsion is discovered, the contralateral testicle should undergo fixation to reduce the risk of asynchronous torsion.

  5. Torsion gelometry of cheese.

    PubMed

    Tunick, M H; Van Hekken, D L

    2002-11-01

    Torsion gelometry, a fundamental rheological test in which specimens are twisted until they fracture, was applied to several different cheese varieties to determine its suitability for measuring their textural properties. Fresh and aged Brick, Cheddar, Colby, Gouda, Havarti, Mozzarella, and Romano cheeses were subjected to torsion analysis, and the results were compared with those from small amplitude oscillatory shear (SAOS) tests and texture profile analysis (TPA). Strong relationships (correlation coefficients > 0.8) were found between torsion shear stress and TPA hardness, and between torsion shear strain and TPA cohesiveness. SAOS, which measures rheological properties of intact samples, did not correlate well with torsion or TPA. A map showing trends during aging toward brittle, mushy, rubbery, and tough texture was drawn using the torsion data. The findings show that torsion gelometry provides fundamental rheological data on cheese at the fracture point. The information can be used to compare textural qualities of cheese samples as they are being cut.

  6. Distinguishing the roles of Topoisomerases I and II in relief of transcription-induced torsional stress in yeast rRNA genes.

    PubMed

    French, Sarah L; Sikes, Martha L; Hontz, Robert D; Osheim, Yvonne N; Lambert, Tashima E; El Hage, Aziz; Smith, Mitchell M; Tollervey, David; Smith, Jeffrey S; Beyer, Ann L

    2011-02-01

    To better understand the role of topoisomerase activity in relieving transcription-induced supercoiling, yeast genes encoding rRNA were visualized in cells deficient for either or both of the two major topoisomerases. In the absence of both topoisomerase I (Top1) and topoisomerase II (Top2) activity, processivity was severely impaired and polymerases were unable to transcribe through the 6.7-kb gene. Loss of Top1 resulted in increased negative superhelical density (two to six times the normal value) in a significant subset of rRNA genes, as manifested by regions of DNA template melting. The observed DNA bubbles were not R-loops and did not block polymerase movement, since genes with DNA template melting showed no evidence of slowed elongation. Inactivation of Top2, however, resulted in characteristic signs of slowed elongation in rRNA genes, suggesting that Top2 alleviates transcription-induced positive supercoiling. Together, the data indicate that torsion in front of and behind transcribing polymerase I has different consequences and different resolution. Positive torsion in front of the polymerase induces supercoiling (writhe) and is largely resolved by Top2. Negative torsion behind the polymerase induces DNA strand separation and is largely resolved by Top1.

  7. miR-155 activates cytokine gene expression in Th17 cells by regulating the DNA-binding protein Jarid2 to relieve polycomb-mediated repression.

    PubMed

    Escobar, Thelma M; Kanellopoulou, Chrysi; Kugler, David G; Kilaru, Gokhul; Nguyen, Cuong K; Nagarajan, Vijayaraj; Bhairavabhotla, Ravikiran K; Northrup, Daniel; Zahr, Rami; Burr, Patrick; Liu, Xiuhuai; Zhao, Keji; Sher, Alan; Jankovic, Dragana; Zhu, Jinfang; Muljo, Stefan A

    2014-06-19

    Specification of the T helper 17 (Th17) cell lineage requires a well-defined set of transcription factors, but how these integrate with posttranscriptional and epigenetic programs to regulate gene expression is poorly understood. Here we found defective Th17 cell cytokine expression in miR-155-deficient CD4+ T cells in vitro and in vivo. Mir155 was bound by Th17 cell transcription factors and was highly expressed during Th17 cell differentiation. miR-155-deficient Th17 and T regulatory (Treg) cells expressed increased amounts of Jarid2, a DNA-binding protein that recruits the Polycomb Repressive Complex 2 (PRC2) to chromatin. PRC2 binding to chromatin and H3K27 histone methylation was increased in miR-155-deficient cells, coinciding with failure to express Il22, Il10, Il9, and Atf3. Defects in Th17 cell cytokine expression and Treg cell homeostasis in the absence of Mir155 could be partially suppressed by Jarid2 deletion. Thus, miR-155 contributes to Th17 cell function by suppressing the inhibitory effects of Jarid2.

  8. miR-155 activates cytokine gene expression in Th17 cells by regulating the DNA-binding protein Jarid2 to relieve Polycomb-mediated repression

    PubMed Central

    Escobar, Thelma M.; Kanellopoulou, Chrysi; Kugler, David G.; Kilaru, Gokhul; Nguyen, Cuong K.; Nagarajan, Vijayaraj; Bhairavabhotla, Ravikiran K.; Northrup, Daniel; Zahr, Rami; Burr, Patrick; Liu, Xiuhuai; Zhao, Keji; Sher, Alan; Jankovic, Dragana; Zhu, Jinfang; Muljo, Stefan A.

    2014-01-01

    Specification of the T helper 17 (Th17) cell lineage requires a well defined set of transcription factors, but how these integrate with post-transcriptional and epigenetic programs to regulate gene expression is poorly understood. Here we found defective Th17 cell cytokine expression in miR-155-deficient CD4+ T cells in vitro and in vivo. Mir155 was bound by Th17 cell transcription factors and was highly expressed during Th17 cell differentiation. miR-155-deficient-Th17 and -T regulatory (Treg) cells expressed increased amounts of Jarid2, a DNA-binding protein that recruits the Polycomb Repressive Complex 2 (PRC2) to chromatin. PRC2 binding to chromatin and H3K27 histone methylation was increased in miR-155-deficient cells, coinciding with failure to express Il22, Il10, Il9 and Atf3. Defects in Th17 cell cytokine expression and Treg cell homeostasis in the absence of Mir155 could be partially suppressed by Jarid2 deletion. Thus, miR-155 contributes to Th17 cell function by suppressing the inhibitory effects of Jarid2. PMID:24856900

  9. Cyclic torsion testing

    NASA Technical Reports Server (NTRS)

    Leese, G. E.

    1984-01-01

    Torsional fatigue testing and data analysis procedures are described. Since there are no standards governing cyclic torsion testing that are generally accepted on a widespread basis by the technical community, the different approaches that dominate current experimental activity, and the ramifications of each are discussed. Particular attention is given to the theoretical and experimental difficulties that have paced refinement and general acceptance of test procedures. Finally, specific quantities and nomenclature modelled after analagous axial fatigue properties are suggested as an effective way to communicate torsional fatigue results until accepted standards are established.

  10. [Omental torsion. Case Report].

    PubMed

    Zaleta-Cruz, Janny Lizbeth; Rojas-Méndez, Javier; Garza-Serna, Ulises; González-Ruvalcaba, Román; Ortiz de Elguea-Lizarraga, José; Flores-Villalba, Eduardo

    Omental torsion is an infrequent cause of acute abdomen and its symptoms are non-specific, often presenting with pain at the right iliac fossa as the only symptom. Its aetiology remains unknown, but different risk factors have been associated with the disease, including obesity, congenital malformations, and tumours. These risk factors have been classified as predisposing or triggering, primary or secondary, and external or internal. The is a case of a 24-year-old male who complained about pain in the right iliac fossa without any other symptoms. The diagnosis was acute appendicitis, but during the laparoscopic approach, omental torsion was found. The diagnosis of omental torsion is is complex. However, computed tomography and ultrasound have been used successfully. The treatment for omental torsion is the resection of necrotised tissue by a laparoscopic approach. Copyright © 2015 Academia Mexicana de Cirugía A.C. Publicado por Masson Doyma México S.A. All rights reserved.

  11. Affine dynamics with torsion

    NASA Astrophysics Data System (ADS)

    Gültekin, Kemal

    2016-03-01

    In this study, we give a thorough analysis of a general affine gravity with torsion. After a brief exposition of the affine gravities considered by Eddington and Schrödinger, we construct and analyze different affine gravities based on the determinants of the Ricci tensor, the torsion tensor, the Riemann tensor, and their combinations. In each case we reduce equations of motion to their simplest forms and give a detailed analysis of their solutions. Our analyses lead to the construction of the affine connection in terms of the curvature and torsion tensors. Our solutions of the dynamical equations show that the curvature tensors at different points are correlated via non-local, exponential rescaling factors determined by the torsion tensor.

  12. [Adnexal torsion: three cases].

    PubMed

    Sánez, Henry Aristóteles Mateo; Taboada-Pérez, Grecia Carolina; Hernández-Arroyo, Lysandra; Mateo-Madrigal, Melissa; Mateo-Madrigal, Victoria

    2013-05-01

    Adnexal torsion is a gynecological emergency caused by the torsion of the ovary over its pedicle producing lymphatic and venous stasis, later it develops into ischemia and necrosis, when is not treated. Until recently, the treatment for adnexal torsion has been adnexectomy. This paper report three cases treated successfully with conservative treatment. It is essential to establish a protocol for adnexal torsion management where radical treatments are abandoned and conservative surgeries, such as detorsion and plication, are performed. We suggest as a first choice management adnexal detorsion, in case malignity is suspected to have intraoperative pathologic analysis, and based on the results to decide to preserve the adnexal or remove it for definitive cure.

  13. Testicular Torsion (For Parents)

    MedlinePlus

    ... immediate surgery to save the testicle. For most boys, talking seriously about their private parts can be ... twist within the scrotum. Torsion can happen to boys and men of any age, but is most ...

  14. Torsion-mediated interaction between adjacent genes.

    PubMed

    Meyer, Sam; Beslon, Guillaume

    2014-09-01

    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.

  15. 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

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

    MedlinePlus

    ... two pain relievers kids take most often are ibuprofen (say: i-byoo-PRO-fen) and acetaminophen (say: ... away! When you take a pain reliever like ibuprofen, it keeps injured or damaged cells from making ...

  17. 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 ...

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

    MedlinePlus

    ... Short All About Puberty How Do Pain Relievers Work? KidsHealth > For Kids > How Do Pain Relievers Work? Print A A A en español ¿Cómo actúan ... the spot that hurts so much. Pain relievers work with your cells, your body's nerve endings, your ...

  19. Relieving pain with nerve blocks.

    PubMed

    Carron, H

    1978-04-01

    Pain syndromes in elderly patients are seldom psychogenic or due merely to "old age." Careful differential diagnosis is important, as judicious use of nerve blocks as adjunctive therapy often can relieve pain and restore activity. In the acute phase of shoulder pain, intrabursal injection of local anesthetic and steroid inhibits the inflammatory process. In the later stages, suprascapular nerve block relieves pain and interrupts afferent pain pathways. The occipital pain and headache of cervical arthritis also often respond to injection of 2 to 3 ml of long-acting anesthetic into the greater and lesser occipital nerves at the sites where they pierce the trapezius. Minor causalgia, shoulder-arm syndrome, or chronic traumatic edema may follow either forearm fracture or inflammation around the shoulder joint. Five stellate ganglion blocks with 1% lidocaine on alternate days, followed by 3 to 4 months of active and passive exercise, is the most effective treatment. This regimen usually produces a fully functional extremity. In degenerative disk disease, osteoarthritis, and metastatic disease, the cause of back pain is essentially the same--edema and inflammation of nerve roots at the intervertebral foramina. Injection of local anesthetic and steroid into the epidural space usually reduces swelling and inflammation. Patients are evaluated in 2 weeks and reblocked if improvement has plateaued. Pain relief most often is prompt and persists for an indefinite period.

  20. 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.

  1. Testicular Torsion (For Parents)

    MedlinePlus

    ... damaged. As a general rule: within about 4-6 hours of the start of the torsion, the testicle can be saved 90% of the time after 12 hours, this drops to 50% after 24 hours, the testicle can be saved only 10% ...

  2. Spin on perinatal testicular torsion.

    PubMed

    Samnakay, Naeem; Tudehope, David; Walker, Rosslyn

    2006-11-01

    We describe a recent case of perinatal testicular torsion at our institution. The presentation, management and outcome of perinatal testicular torsion are quite different to testicular torsion in the general paediatric population. The literature describes a variety of management options for perinatal testicular torsion and these are briefly reviewed. In cases of unilateral perinatal testicular torsin, there is controversy over whether surgery to fix the contralateral testis is required, and if so, the appropriate timing for the surgery. A good understanding of the issues unique to perinatal torsion will facilitate appropriate counseling of parents of affected neonates.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Torsion of wandering spleen.

    PubMed

    Dirican, A; Burak, I; Ara, C; Unal, B; Ozgor, D; Meydanli, M M

    2009-01-01

    Wandering spleen is characterized by ectopic localization of spleen owing to the lack or weakening of the major splenic ligaments. In present study, two cases with torsion of wandering spleen were reported. The first case was a 30-year-old female who was admitted to emergency department with acute abdominal pain and vomiting. Abdominal Ultrasonography and computed tomography showed a round solid hypodense mass that was located in the left hypochondriac region of abdomen. At laparotomy, the patient was found to have torsion of a wandering spleen with complete infarction and pancreatic tail infarction. Splenectomy and distal pancreatectomy were performed. The second patient was a 19-year-old female. She was admitted to emergency department with abdominal pain. Axial computed tomography (CT) showed pelvic mass that indicated a possibility of a wandering spleen. The wandering spleen was removed with its long pedicle because of infarction. Torsion of wandering spleen must be considered in differential diagnosis of acute abdomen when a palpable painful abdominal mass is present on physical examination, and the spleen is absent in its normal anatomical location on radiological examination (Fig. 4, Ref. 8). Full Text (Free, PDF) www.bmj.sk.

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

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... before relieving to atmosphere. When relieving to atmosphere, a relief valve shall be fitted in the... relieve to the condenser which in turn may relieve either to the low side or to atmosphere. It shall be...

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

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... before relieving to atmosphere. When relieving to atmosphere, a relief valve shall be fitted in the... relieve to the condenser which in turn may relieve either to the low side or to atmosphere. It shall be...

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

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... before relieving to atmosphere. When relieving to atmosphere, a relief valve shall be fitted in the... relieve to the condenser which in turn may relieve either to the low side or to atmosphere. It shall be...

  11. Torsion effects in braneworld scenarios

    SciTech Connect

    Hoff da Silva, J. M.; Rocha, R. da

    2010-01-15

    We present gravitational aspects of braneworld models endowed with torsion terms both in the bulk and on the brane. In order to investigate a conceivable and measurable gravitational effect, arising genuinely from bulk torsion terms, we analyze the variation in the black hole area by the presence of torsion. Furthermore, we extend the well-known results about consistency conditions in a framework that incorporates brane torsion terms. It is shown, in a rough estimate, that the resulting effects are generally suppressed by the internal space volume. This formalism provides manageable models and their possible ramifications into some aspects of gravity in this context, and cognizable corrections and physical effects as well.

  12. Torsional nystagmus in hypothalamic hamartoma.

    PubMed

    Shaikh, Aasef G

    2013-12-01

    Torsional nystagmus was noted in a patient with hypothalamic hamartoma. Magnetic resonance imaging revealed an exophytic hypothalamic mass extending into the pre-pontine cistern and abutting ventral mesencephalon. The quickphase of the torsional nystagmus was directed towards the left side, ipsilateral to the side of compression by the hamartoma. Ipsi-lesionally directed pure torsional nystagmus in this case is attributed to the compressive lesion of ocular motor structures responsible for the neural integration of torsional and vertical eye movements, the interstitial nucleus of Cajal. [Published with video sequences].

  13. Torsion of Accessory Hepatic Lobe

    PubMed Central

    Natarajan, Saravanan; Jayasudha; Periasamy, Manikandhan; Rangasamy, Saminathan

    2017-01-01

    An accessory hepatic lobe is a rare congenital anomaly that can undergo torsion and present as an acute surgical emergency. A 5-year-old child admitted as acute abdomen, on laparotomy found to have torsion of accessory lobe of liver, is being reported. PMID:28082782

  14. Inversion Therapy: Can It Relieve Back Pain?

    MedlinePlus

    ... pain Does inversion therapy relieve back pain? Is it safe? Answers from Edward R. Laskowski, M.D. ... t provide lasting relief from back pain, and it's not safe for everyone. Inversion therapy involves hanging ...

  15. Pain Relievers: MedlinePlus Health Topic

    MedlinePlus

    ... Medicines (American Academy of Family Physicians) Also in Spanish Pain Relievers: Understanding Your OTC Options (American Academy of Family Physicians) Also in Spanish Latest News Addictive Opioids Common for People on ...

  16. Topical Pain Relievers May Cause Burns

    MedlinePlus

    ... and joint pain relievers containing the active ingredients menthol, methyl salicylate and capsaicin. These cases were uncovered ... of people who purchase these products, Tan notes. Menthol, methyl salicylate and capsaicin create sensations of local ...

  17. Can Botox Injections Relieve Arthritis Pain?

    MedlinePlus

    ... Botox injections relieve arthritis pain? Answers from April Chang-Miller, M.D. Botox injections into arthritic joints ... focus of most arthritis treatment plans. With April Chang-Miller, M.D. References Hameed F, et al. ...

  18. Carpal Tunnel Exercises: Can They Relieve Symptoms?

    MedlinePlus

    ... carpal tunnel syndrome. Would regular hand and wrist exercises help me avoid surgery? Answers from Peter C. ... D. Probably not. When used alone, carpal tunnel exercises aren't likely to relieve symptoms, such as ...

  19. 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.

  20. Inverse problems for torsional modes.

    USGS Publications Warehouse

    Willis, C.

    1984-01-01

    Considers a spherically symmetric, non-rotating Earth consisting of an isotropic, perfect elastic material where the density and the S-wave velocity may have one or two discontinuities in the upper mantle. Shows that given the velocity throughout the mantle and the crust and given the density in the lower mantle, then the freqencies of the torsional oscillations of one angular order (one torsional spectrum), determine the density in the upper mantle and in the crust uniquely. If the velocity is known only in the lower mantle, then the frequencies of the torsional oscillations of two angular orders uniquely determine both the density and the velocity in the upper mantle and in the crust. In particular, the position and size of the discontinuities in the density and velocity are uniquely determined by two torsional spectra.-Author

  1. Axions in gravity with torsion

    NASA Astrophysics Data System (ADS)

    Castillo-Felisola, Oscar; Corral, Cristóbal; Kovalenko, Sergey; Schmidt, Iván; Lyubovitskij, Valery E.

    2015-04-01

    We study a scenario allowing a solution of the strong charge parity problem via the Peccei-Quinn mechanism, implemented in gravity with torsion. In this framework there appears a torsion-related pseudoscalar field known as the Kalb-Ramond axion. We compare it with the so-called Barbero-Immirzi axion recently proposed in the literature also in the context of the gravity with torsion. We show that they are equivalent from the viewpoint of the effective theory. The phenomenology of these torsion-descended axions is completely determined by the Planck scale without any additional model parameters. These axions are very light and very weakly interacting with ordinary matter. We briefly comment on their astrophysical and cosmological implications in view of the recent BICEP2 and Planck data.

  2. 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

  3. Protective effect of thymoquinone against testicular torsion induced oxidative injury.

    PubMed

    Ayan, M; Tas, U; Sogut, E; Caylı, S; Kaya, H; Esen, M; Erdemir, F; Uysal, M

    2016-03-01

    We aimed to determine the protective effects of thymoquinone (TQ), against ischaemia-reperfusion (I/R) injury in the testis tissue of rats. Twenty-seven male Wistar albino rats were randomly divided into three equal groups as follows: Group I, sham group; Group II, torsion group; and Group III, torsion + thymoquinone group. The ischaemia period was 2 h, and orchiectomy was performed after 30 min of detorsion. Testis tissue sections were analysed with the terminal transferase mediated dUTP-nick end labelling (TUNEL) assay to determine in situ apoptotic DNA fragmentation. Additionally, Caspase 3 and Bax proteins were analysed immunohistochemically. The superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) activity levels in the testis tissue were also measured. The superoxide dismutase activity and malondialdehyde levels in the torsion group were significantly higher than those of the sham group (P < 0.05). Thymoquinone administration significantly reduced these levels. Torsion significantly increased active-Caspase 3 and Bax expression, which was decreased by thymoquinone. The apoptotic index of the torsion group was significantly higher than that of the control group. However, thymoquinone significantly reduced the apoptotic index (P < 0.05). Our results indicate that thymoquinone plays a protective role in oxidative stress induced ischaemia-reperfusion in the testis tissue of rats.

  4. Case reports: compounding to relieve arthritis pain.

    PubMed

    Marshall, Robert; Vidaurri, Vincent A; Boomsma, Diane; Buchta, Anthony J; Vail, Jane

    2008-01-01

    Arthritis is an ancient disorder that defies cure. The management of arthritis may require medication, surgery, and/or nonpharmacologic treatment, and patients whose pain responds to drug therapy often achieve substantial benefit from a compounded preparation. Customized to include analgesics in combinations and concentrations not found in commercially manufactured medications, a pain-relieving compound can be prepared in a transdermal form that minimizes the risk of adverse effects associated with some oral medications. In this article, we present case reports of patients whose arthritic pain was relieved by a pharmaceutical compound. Formulations effective in treating inflammatory pain are also provided.

  5. Evidence that processing of ribonucleotides in DNA by topoisomerase 1 is leading-strand specific.

    PubMed

    Williams, Jessica S; Clausen, Anders R; Lujan, Scott A; Marjavaara, Lisette; Clark, Alan B; Burgers, Peter M; Chabes, Andrei; Kunkel, Thomas A

    2015-04-01

    Ribonucleotides incorporated during DNA replication are removed by RNase H2-dependent ribonucleotide excision repair (RER). In RER-defective yeast, topoisomerase 1 (Top1) incises DNA at unrepaired ribonucleotides, initiating their removal, but this is accompanied by RNA-DNA-damage phenotypes. Here we show that these phenotypes are incurred by a high level of ribonucleotides incorporated by a leading strand-replicase variant, DNA polymerase (Pol) ɛ, but not by orthologous variants of the lagging-strand replicases, Pols α or δ. Moreover, loss of both RNases H1 and H2 is lethal in combination with increased ribonucleotide incorporation by Pol ɛ but not by Pols α or δ. Several explanations for this asymmetry are considered, including the idea that Top1 incision at ribonucleotides relieves torsional stress in the nascent leading strand but not in the nascent lagging strand, in which preexisting nicks prevent the accumulation of superhelical tension.

  6. Neonatal Testicular Torsion; a Review Article

    PubMed Central

    Riaz-Ul-haq, Muhammad; Mahdi, Diaa Eldin Abdelhamid; Elhassan, Elbagir Uthman

    2012-01-01

    Neonatal testicular torsion, also known as perinatal testicular torsion is a subject of debate among surgeons. Neonatal testicular torsion either intrauterine or postnatal results into extravaginal torsion which is a different entity than intravaginal type but has the same devastating consequences if not diagnosed and managed well in time. Testicular torsion results into acute ischemia with its resultant sequelae such as abnormality of testicular function and fertility. Urgent surgical exploration and fixation of the other testis are the key points in the management. General anesthesia is not a contraindication for exploration as thought before. Diagnosis and controversies on management of testicular torsion are discussed in this review. PMID:23400637

  7. Propagating torsion in the Einstein frame

    NASA Astrophysics Data System (ADS)

    Popławski, Nikodem J.

    2006-11-01

    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.

  8. [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.

  9. 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.

  10. Urban-Rural Education: "Relieving the Tension".

    ERIC Educational Resources Information Center

    Easley, Edgar M.

    As part of a panel on rural education, Dr. Edgar M. Easley spoke on the topic "Urban-Rural Education - Relieving the Tension". Based on findings from literature of adult migration to urban areas, Dr. Easley stated the following implications for adult education teachers and administrators: (1) that the tension found in rural migrants related to…

  11. 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.

  12. Torsional carbon nanotube artificial muscles.

    PubMed

    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

    2011-10-28

    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.

  13. 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.

  14. 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.

  15. Torsional rigidity, isospectrality and quantum graphs

    NASA Astrophysics Data System (ADS)

    Colladay, Don; Kaganovskiy, Leon; McDonald, Patrick

    2017-01-01

    We study torsional rigidity for graph and quantum graph analogs of well-known pairs of isospectral non-isometric planar domains. We prove that such isospectral pairs are distinguished by torsional rigidity.

  16. Wandering spleen with chronic torsion.

    PubMed

    Misawa, Takeyuki; Yoshida, Kazuhiko; Shiba, Hiroaki; Kobayashi, Susumu; Yanaga, Katsuhiko

    2008-04-01

    Wandering spleen, a rare clinical entity with a high incidence of splenic torsion and infarction, was preoperatively diagnosed in a 28-year-old woman. Axial computed tomography showed the absence of the spleen in the left subphrenic space and a spleen-like mass in the pelvis, suggestive of a wandering spleen. A coronal contrast-enhanced computed tomography image exhibited the enlarged spleen suspended by elongated, dilated, and somewhat tortuous splenic vessels. Owing to the symptomatic splenomegaly with hypersplenism and chronic torsion, laparoscopic splenectomy was performed.

  17. Torsion of a wandering spleen

    PubMed Central

    Jude, Nwashilli N.; Onochie, Nwajei C.

    2015-01-01

    Wandering spleen is a rare condition that accounts for less than 0.25% of all indications for splenectomy. It is characterized by ectopic localization of the spleen owing to the lack or weakening of its ligaments. Torsion is the most common complication due to its long pedicle and high mobility, which may result in acute abdomen. We report a case of torsion in a wandering spleen in a 28-year-old male presenting with an acute abdomen that was treated by splenectomy. PMID:26620993

  18. Torsion Modified Plasma Screening in Astrophysics

    NASA Astrophysics Data System (ADS)

    Sivaram, C.; Garcia de Andrade, L. C.

    The torsion modified Maxwell-Proca equations when applied to describe a plasma is shown to lead to a correction to the Debye screening length. For hot new born neutron stars the torsion correction is shown to be significant. This effect may provide an indirect evidence for torsion.

  19. Pancreatic torsion in a dog

    PubMed Central

    Brabson, Tamera L.; Maki, Lynn C.; Newell, Susan M.; Ralphs, S. Christopher

    2015-01-01

    A 6-month-old male intact Cane Corso mastiff dog was presented for a recent history of vomiting, abdominal pain, and lethargy. A diagnosis of pancreatic torsion was made during abdominal exploratory surgery and was confirmed with histopathology. The dog underwent partial pancreatectomy and recovered with no complications. PMID:25969579

  20. [Testicular torsion: A case report].

    PubMed

    García-Fernández, Gustavo; Bravo-Hernández, Alberto; Bautista-Cruz, Raúl

    2016-07-13

    The acute scrotum is an emergency. Testicular torsion represents approximately 25% of the causes. The annual incidence of testicular torsion is approximately 1/4,000 persons under 25 years, with highest prevalence between 12 and 18 years old. It usually occurs without apparent cause, but it has been associated with anatomical, traumatic, and environmental factors, among others. A male 15 year-old male, with no history of importance, was seen in the Emergency Department, presenting with a sudden and continuous pain in the left testicle. It was accompanied by a pain that radiated to the abdomen and left inguinal area, with nausea and vomiting of more than 12h onset. Doppler ultrasound showed changes suggestive of testicular torsion. Surgery was performed that showed findings of a necrotic left testicle with rotation of the spermatic cord of 360°. A left orchiectomy was performed. Testicular torsion should always be considered one of the leading causes of acute scrotal pain. Delays in diagnosis should be avoided as this is directly related to the percentage of testicular salvage or loss. Copyright © 2016 Academia Mexicana de Cirugía A.C. Publicado por Masson Doyma México S.A. All rights reserved.

  1. Pain Relievers - Multiple Languages: MedlinePlus

    MedlinePlus

    ... List of All Topics All Pain Relievers - Multiple Languages To use the sharing features on this page, please enable JavaScript. Chinese - Traditional (繁體中文) French (français) Japanese (日本語) Korean (한국어) Russian (Русский) Somali (af Soomaali) Spanish (español) Ukrainian (Українська) ...

  2. Torsion-Angle Molecular Dynamics as a New Efficient Tool for NMR Structure Calculation

    NASA Astrophysics Data System (ADS)

    Stein, Evan G.; Rice, Luke M.; Brünger, Axel T.

    1997-01-01

    Molecular dynamics in torsion-angle space was applied to nuclear magnetic resonance structure calculation using nuclear Overhauser effect-derived distances andJ-coupling-constant-derived dihedral angle restraints. Compared to two other commonly used algorithms, molecular dynamics in Cartesian space and metric-matrix distance geometry combined with Cartesian molecular dynamics, the method shows increased computational efficiency and success rate for large proteins, and it shows a dramatically increased radius of convergence for DNA. The torsion-angle molecular dynamics algorithm starts from an extended strand conformation and proceeds in four stages: high-temperature torsion-angle molecular dynamics, slow-cooling torsion-angle molecular dynamics, Cartesian molecular dynamics, and minimization. Tests were carried out using experimental NMR data for protein G, interleukin-8, villin 14T, and a 12 base-pair duplex of DNA, and simulated NMR data for bovine pancreatic trypsin inhibitor. For villin 14T, a monomer consisting of 126 residues, structure determination by torsion-angle molecular dynamics has a success rate of 85%, a more than twofold improvement over other methods. In the case of the 12 base-pair DNA duplex, torsion-angle molecular dynamics had a success rate of 52% while Cartesian molecular dynamics and metric-matrix distance geometry always failed.

  3. Torsional electromechanical quantum oscillations in carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Cohen-Karni, Tzahi; Segev, Lior; Srur-Lavi, Onit; Cohen, Sidney R.; Joselevich, Ernesto

    2006-10-01

    Carbon nanotubes can be distinctly metallic or semiconducting depending on their diameter and chirality. Here we show that continuously varying the chirality by mechanical torsion can induce conductance oscillations, which can be attributed to metal-semiconductor periodic transitions. The phenomenon is observed in multiwalled carbon nanotubes, where both the torque and the current are shown to be carried predominantly by the outermost wall. The oscillation period with torsion is consistent with the theoretical shifting of the corners of the first Brillouin zone of graphene across different sub-bands allowed in the nanotube. Beyond a critical torsion, the conductance irreversibly drops due to torsional failure, allowing us to determine the torsional strength of carbon nanotubes. Carbon nanotubes could be ideal torsional springs for nanoscopic pendulums, because electromechanical detection of motion could replace the microscopic detection techniques used at present. Our experiments indicate that carbon nanotubes could be used as electronic sensors of torsional motion in nanoelectromechanical systems.

  4. 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.

  5. Torsion of a wandering spleen.

    PubMed

    El Bouhaddouti, Hicham; Lamrani, Jihane; Louchi, Abdellatif; El Yousfi, Mounia; Aqodad, Noureddine; Ibrahimi, Adil; Boubou, Meriem; Kamaoui, Imane; Tizniti, Siham

    2010-01-01

    Wandering spleen is a rare condition defined as a mobile spleen only attached with its pedicle. It can be complicated by a volvulus, which is a surgical abdominal emergency. Preventing infarction is the aim of a prompt surgery that can preserve the spleen and then proceed to splenopexy. We report a rare case of torsion of a wandering spleen associated with a dolichosigmoοd.

  6. Torsional Split Hopkinson Bar Optimization

    DTIC Science & Technology

    2012-04-10

    is the torsional wave speed . Also, one can relate the torque with the yield stress of the material, as seen in equation 2; where r is the radius of...be equal to the mechanical impedance of the bars. In other words, the product of density, speed of wave and polar moment of inertia must remain...pillow blocks used to mount the incident and transmitter bars are cast iron based- mounted Babbitt-lined bearing split, for 1 in. shaft diameter

  7. 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.

  8. Torsional resistance of retreatment instruments.

    PubMed

    Lopes, Hélio P; Elias, Carlos N; Vedovello, Gislaine A F; Bueno, Carlos E S; Mangelli, Marcelo; Siqueira, José F

    2011-10-01

    This study compared the torsional resistance of two brands of rotary nickel-titanium (NiTi) instruments indicated for endodontic retreatment. Mtwo retreatment instruments #15 and #25 (VDW, Munich, Germany) and ProTaper Universal retreatment instruments D2 and D3 (Maillefer/Dentsply, Ballaigues, Switzerland) were subjected to a torsional assay in clockwise rotation. The two parameters evaluated were maximum torque and angular deflection at failure. Fractured instruments had their fractured surfaces and helical shafts examined by scanning electron microscopy. The results indicated that the angular deflection at fracture decreased in the following order: Mtwo retreatment file #15 > Mtwo retreatment file #25 > ProTaper Universal retreatment file D2 > ProTaper Universal retreatment file D3. As for the maximum torque values, the results revealed the following descending order: ProTaper Universal file D2 > Mtwo retreatment file #25 > ProTaper Universal file D3 > Mtwo retreatment file #15. Scanning electron microscopic analysis revealed that plastic deformation occurred along the helical shaft of the fractured instruments. Fractured surfaces were of the ductile type. The instruments tested showed different torsional behavior depending on the parameter evaluated. If one considers that high angular deflection values may serve as a safety factor, then the Mtwo retreatment instruments showed significantly better results. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  9. Les torsions sur testicules cryptorchides

    PubMed Central

    Gharbi, Mohamed; Amri, Najmeddine; Chambeh, Wahib; Braiek, Salem; Kamel, Rafik El

    2010-01-01

    Résumé But : La cryptorchidie est une pathologie assez fréquente en urologie. Elle est associée à un risque élevé d’infertilité et de dégénérescence. Elle semble aussi être associée à un risque important de torsion. Cette entité est très peu abordée dans la littérature. Nous rapportons tous les cas de torsion sur testicule cryptorchide observés à notre service dans le but de mieux caractériser cette pathologie et de réduire ainsi le taux d’orchidectomies. Méthodologie : Il s’agit d’une étude rétrospective portant sur tous les cas de torsion sur testicule cryptorchide opérés dans notre service d’urologie entre 1999 et 2007. Les patients ont fait l’objet d’une description basée sur le résumé de leurs observations. Résultats : Les patients étaient âgés de 7 mois à 39 ans. La torsion touchait le testicule droit dans 53 % des cas. Le tableau clinique comportait une douleur au niveau de la région inguinale d’apparition soudaine avec une masse sous-cutanée inflammatoire et douloureuse à ce niveau et surtout un hémiscrotum homolatéral vide. Dans 60 % des cas, le diagnostic était tardif et une orchidectomie a été réalisée. Dans les autre cas, un abaissement du testicule a été réalisé avec orchidopexie controlatéral dans le même temps opératoire. Conclusion : Bien qu’il s’agisse d’une pathologie peu courante, la torsion sur testicule cryptorchide doit être étudiée davantage. Le diagnostic précoce permettra de sauver et d’abaisser le testicule et faciliter ainsi le dépistage d’une éventuelle dégénérescence. PMID:21191497

  10. Intranatal Torsion of Polydactyly: A Rare Event.

    PubMed

    Gupta, Priyanka; Neogi, Sujoy; Shukla, Amlin; Patwari, A K

    2016-01-01

    Polydactyly is one of the most common anomalies of hand and/or foot. Postnatal torsion of pedunculated polydactyly is a well known complication but intranatal torsion has been infrequently described in published literature. Here, we describe a case of pedunculated ulnar polydactyly which was gangrenous at birth due to intranatal torsion. Controversies surrounding the management of narrow pedicled pedunculated polydactyly by traditional method of suture ligation at base are also discussed.

  11. [A case of neonatal testicular torsion].

    PubMed

    Nishizawa, Satoshi; Nanpo, Yoshihito; Kuramoto, Tomomi; Iba, Akinori; Fujii, Reona; Matsumura, Nagahide; Shintani, Yasuyo; Inagaki, Takeshi; Kohjimoto, Yasuo; Hara, Isao

    2008-12-01

    An infant normally delivered at the 38th week of gestation was referred to our department one day after birth for a firm and painless right hemiscrotal mass with bluish coloration. Since contralateral scrotum showed swelling, we performed emergency surgery on that day. The right spermatic cord was constricted due to extravaginal torsion, and degree and direction of torsion was unclear since the spermatic cord was already organized. Right testis showed irreversible necrotic change, requiring orchiectomy. We confirmed that left testis was intact and performed orchidopexy. Since high incidence of contralateral asymptomatic torsion has been reported in patients with prenatal testicular torsion, emergency surgery should be considered when contralateral scrotum shows abnormal findings.

  12. Bulk micromachined quasistatic torsional micromirror

    NASA Astrophysics Data System (ADS)

    Kiessling, Torsten; Wolter, Alexander; Schenk, Harald; Lakner, Hubert

    2004-01-01

    One dimensional torsional micro mirrors for laser steering applications have been developed and manufactured at Fraunhofer Institute of Photonic Microsystems. Several design variations with rectangular plates are available. The device can be operated in resonant mode and quasistatic mode as well. The device is fabricated out of a BSOI wafer and a second conductive silicon wafer. The structure is assembled by conductive adhesive bonding. Torsional springs connect the mirror plate to the mirror frame mechanically and electrically. Filled isolation trench structures separate volumes of different electrical potentials at the frame and at the deflective mirror respectively. Comb drive structures at both sides of the deflectable mirror and the part of frame located opposite increases capacitance at both mirror half sides. Applying a low level drive voltage between the combs, the mirror can be operated in resonant mode. The second silicon wafer is placed below the deflective mirror and is electrically at ground. Applying a electrical potential of higher level to one side of the deflectable mirror, the mirror can be driven quasistatic and resonant as well. While the drive voltage is applied to one side of the mirror, the comb drive structure of the opposite side can be used for capacitance based position read out.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. Torsional and rotational couplings in nonrigid molecules

    NASA Astrophysics Data System (ADS)

    Omiste, Juan J.; Madsen, Lars Bojer

    2017-02-01

    We analyze theoretically the interplay between the torsional and the rotational motion of an aligned biphenyl-like molecule. To do so, we consider a transition between two electronic states with different internal torsional potentials, induced by means of a resonant laser pulse. The change in the internal torsional potential provokes the motion of the torsional wave packet in the excited electronic state, modifying the structure of the molecule, and hence, its inertia tensor. We find that this process has a strong impact on the rotational wave function, displaying different behavior depending on the electronic states involved and their associated torsional potentials. We describe the dynamics of the system by considering the degree of alignment and the expectation values of the angular momentum operators for the overall rotation of the molecule.

  18. Inelastic torsion of steel I-beams

    NASA Astrophysics Data System (ADS)

    Pi, Y. L.; Trahair, N. S.

    1993-09-01

    A nonlinear inelastic analysis of the non-uniform torsion of I-section beams is presented in this paper. Large twist rotations are included in the geometry non-linearity. The nonlinear equilibrium equations of beams in nonuniform torsion have been derived and a finite element procedure has been developed based on the analysis. The elastic-plastic behavior of beams in non-uniform torsion is studied using the finite element procedure and the results are compared with tests. It is found that I-section beams have much larger torsional capacities than can be predicted by linear plastic collapse analysis, and that torsional failure occurs not by the formation of a mechanism but by the tensile rupture of the flanges. A method is proposed for calculating the full plastic non-uniform torque for practical design purposes.

  19. Direct measurement of torsional properties of single fibers

    NASA Astrophysics Data System (ADS)

    Liu, Dabiao; Peng, Kai; He, Yuming

    2016-11-01

    In order to characterize the torsional behavior of micron-scale specimens, a direct technique is established based on the principle of torsion balance. The technique applies twist to the specimen and balances the resulting torque against a torsion wire of known torsional rigidity. The torsional rigidity of the torsion wire is determined by a torsion pendulum. To measure the rotation of the torsion wire, a sensitive angle detector, comprising a thin cross-beam attached between the torsion wire and the fiber specimen and a laser displacement sensor, is developed. The presented technique permits the measurement of torque in single fibers as low as 10-9 Nm with a reasonable resolution. Using this technique, torsion tests on micro-diameter copper wires, silver wires and carbon fibers were performed. The longitudinal shear modulus and other torsional properties of these samples, such as yielding shear strength, were obtained.

  20. Thermoelastic damping in torsion microresonators with coupling effect between torsion and bending

    NASA Astrophysics Data System (ADS)

    Tai, Yongpeng; Li, Pu; Fang, Yuming

    2014-02-01

    Predicting thermoelastic damping (TED) is crucial in the design of high Q MEMS resonators. In the past, there have been few works on analytical modeling of thermoelastic damping in torsion microresonators. This could be related to the assumption of pure torsional mode for the supporting beams in the torsion devices. The pure torsional modes of rectangular supporting beams involve no local volume change, and therefore, they do not suffer any thermoelastic loss. However, the coupled motion of torsion and bending usually exists in the torsion microresonator when it is not excited by pure torque. The bending component of the coupled motion causes flexural vibrations of supporting beams which may result in significant thermoelastic damping for the microresonator. This paper presents an analytical model for thermoelastic damping in torsion microresonators with the coupling effect between torsion and bending. The theory derives a dynamic model for torsion microresonators considering the coupling effect, and approximates the thermoelastic damping by assuming the energy loss to occur only in supporting beams of flexural vibrations. The thermoelastic damping obtained by the present model is compared to the measured internal friction of single paddle oscillators. It is found that thermoelastic damping contributes significantly to internal friction for the case of the higher modes at room temperature. The present model is validated by comparing its results with the finite-element method (FEM) solutions. The effects of structural dimensions and other parameters on thermoelastic damping are investigated for the representative case of torsion microresonators.

  1. Torsion dystonia in Panay, Philippines.

    PubMed

    Lee, L V; Pascasio, F M; Fuentes, F D; Viterbo, G H

    1976-01-01

    There is an unusually high frequency of torsion dystonia in Panay. Of the 28 Filipino cases, 23 (82%) are from the island of Panay and 19 of the 23 (82%) are from the province of Capiz. The 28 cases belong to 25 families Six sets of brothers are noted. All are males. Pedigree analysis reveals six families with several members affected. Two families show features suggesting possible sex-linked recessive transmission, a mode of inheritance previously undescribed in the literature. The clinical features of the cases seen in this series differ from previously described cases in the literature in several aspects: (a) sex preponderance--all males; (b) age at onset--older age of onset, mean of 31; (c) hereditary--possible sex-linked recessive transmission; (d) spasmodic eye blinking as first symptom in four patients.

  2. Relative Entropy and Torsion Coupling

    NASA Astrophysics Data System (ADS)

    Lin, Feng-Li; Ning, Bo

    2017-08-01

    Based on the the geometric realization of entanglement entropy via Ryu-Takayanagi formula, in this work we evaluate the relative entropy for the holographic deformed CFT dual to the torsion gravity coupled to the fermions of nonzero vev in the Einstein-Cartan formulation. We find that the positivity and monotonicity of the relative entropy imposes constraint on the strength of axial-current coupling, fermion mass and equation of state. Our work is the first example to demonstrate the nontrivial constraint on the bulk gravity theory from the quantum information inequalities. Especially, this constraint is beyond the symmetry action principle and should be understood as the unitarity constraint. This talk is based on the work [1] of the authors.

  3. 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.

  4. Nonlinear backbone torsional pair correlations in proteins

    NASA Astrophysics Data System (ADS)

    Long, Shiyang; Tian, Pu

    2016-10-01

    Protein allostery requires dynamical structural correlations. Physical origin of which, however, remain elusive despite intensive studies during last two and half decades. Based on analysis of molecular dynamics (MD) simulation trajectories for ten proteins with different sizes and folds, we found that nonlinear backbone torsional pair (BTP) correlations, which are mainly spatially long-ranged and are dominantly executed by loop residues, exist extensively in most analyzed proteins. Examination of torsional motion for correlated BTPs suggested that such nonlinear correlations are mainly associated aharmonic torsional state transitions and in some cases strongly anisotropic local torsional motion of participating torsions, and occur on widely different and relatively longer time scales. In contrast, correlations between backbone torsions in stable α helices and β strands are mainly linear and spatially short-ranged, and are more likely to associate with harmonic local torsional motion. Further analysis revealed that the direct cause of nonlinear contributions are heterogeneous linear correlations. These findings implicate a general search strategy for novel allosteric modulation sites of protein activities.

  5. Nonlinear backbone torsional pair correlations in proteins

    PubMed Central

    Long, Shiyang; Tian, Pu

    2016-01-01

    Protein allostery requires dynamical structural correlations. Physical origin of which, however, remain elusive despite intensive studies during last two and half decades. Based on analysis of molecular dynamics (MD) simulation trajectories for ten proteins with different sizes and folds, we found that nonlinear backbone torsional pair (BTP) correlations, which are mainly spatially long-ranged and are dominantly executed by loop residues, exist extensively in most analyzed proteins. Examination of torsional motion for correlated BTPs suggested that such nonlinear correlations are mainly associated aharmonic torsional state transitions and in some cases strongly anisotropic local torsional motion of participating torsions, and occur on widely different and relatively longer time scales. In contrast, correlations between backbone torsions in stable α helices and β strands are mainly linear and spatially short-ranged, and are more likely to associate with harmonic local torsional motion. Further analysis revealed that the direct cause of nonlinear contributions are heterogeneous linear correlations. These findings implicate a general search strategy for novel allosteric modulation sites of protein activities. PMID:27708342

  6. New insights into perinatal testicular torsion

    PubMed Central

    Van Kerrebroeck, Philip

    2009-01-01

    Perinatal testicular torsion is a relatively rare event that remains unrecognized in many patients or is suspected and treated accordingly only after an avoidable loss of time. The authors report their own experience with several patients, some of them quite atypical but instructive. Missed bilateral torsion is an issue, as are partial torsion, possible antenatal signs, and late presentation. These data are discussed together with the existing literature and may help shed new light on the natural course of testicular torsion and its treatment. The most important conclusion is that a much higher index of suspicion based on clinical findings is needed for timely detection of perinatal torsion. It is the authors’ opinion that immediate surgery is mandatory not only in suspected bilateral torsions but also in cases of possible unilateral torsions. There is no place for a more fatalistic “wait-and-see” approach. Whenever possible, even necrotic testes should not be removed during surgery because some endocrine function may be retained. PMID:19856186

  7. 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...

  8. 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...

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

    PubMed

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

    1996-10-15

    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.

  10. Torsion of wandering spleen and distal pancreas

    SciTech Connect

    Sheflin, J.R.; Lee, C.M.; Kretchmar, K.A.

    1984-01-01

    Wandering spleen is the term applied to the condition in which a long pedicle allows the spleen to lie in an abnormal location. Torsion of a wandering spleen is an unusual cause of an acute abdomen and is rarely diagnosed preoperatively. Associated torsion of the distal pancreas is even more uncommon. The authors describe a patient with torsion of a wandering spleen and distal pancreas, who was correctly diagnosed, and define the merits of the imaging methods used. The initial examination should be /sup 99//sup m/Tc-sulfur colloid liner-spleen scanning.

  11. 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.

  12. Torsional Resonators Based on Inorganic Nanotubes.

    PubMed

    Divon, Yiftach; Levi, Roi; Garel, Jonathan; Golberg, Dmitri; Tenne, Reshef; Ya'akobovitz, Assaf; Joselevich, Ernesto

    2017-01-11

    We study for the first time the resonant torsional behaviors of inorganic nanotubes, specifically tungsten disulfide (WS2) and boron nitride (BN) nanotubes, and compare them to that of carbon nanotubes. We have found WS2 nanotubes to have the highest quality factor (Q) and torsional resonance frequency, followed by BN nanotubes and carbon nanotubes. Dynamic and static torsional spring constants of the various nanotubes were found to be different, especially in the case of WS2, possibly due to a velocity-dependent intershell friction. These results indicate that inorganic nanotubes are promising building blocks for high-Q nanoelectromechanical systems (NEMS).

  13. Torsion vehicle model test for automotive vehicle

    NASA Astrophysics Data System (ADS)

    Nor, M. K. Mohd; Ho, C. S.; Ma'at, N.

    2017-04-01

    Torsion vehicle model test of Simple Structural Surfaces (SSS) model for automotive vehicle sedan is proposed in this paper to demonstrate the importance of providing continuous load path within the vehicle structures. The proposed approach is relatively easy to understand as compared to Finite Element Method (FEM). The results prove that the proposed vehicle model test is capable to show that a satisfactory load paths can five a sufficient structural stiffness within the vehicle structure. It is clearly observed that the global torsion stiffness reduces significantly when only one panel is removed from the complete SSS model. The results also five a food agreement with respect to the theoretical hypothesis as the structure is less stiff in torsion in an open section condition. The SSS model and the corresponding torsion test is obviously useful to give an overview of vehicle structural integrity. It can be potentially integrated with FEM to speed up the design process of automotive vehicle.

  14. 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.

  15. Methamphetamine use can mimic testicular torsion.

    PubMed

    Doherty, Michael H; Gerscovich, Eugenio O; Corwin, Michael T; Wilkendorf, Stephen R

    2013-09-01

    We report the case of a patient presenting with the classic clinical appearance of testicular torsion. Ultrasound showed testicular ischemia supporting the clinical diagnosis, but the lack of visualization of spermatic cord torsion was of concern. An attempt of clinical detorsion was considered unsuccessful and the patient was explored. No torsion was found. On postoperative review of the patient's medical history, we found methamphetamine use, with a positive urine test at the time of his emergent consultation for the scrotal pain episode. The use of amphetamines has been previously reported as the cause of ischemia of multiple organs, but we could not find previous reports of involvement of the testis mimicking torsion. Copyright © 2013 Wiley Periodicals, Inc.

  16. Magnetic resonance imaging of experimental testicular torsion.

    PubMed

    Kaipia, A; Ryymin, P; Mäkelä, E; Aaltonen, M; Kähärä, V; Kangasniemi, M

    2005-12-01

    We investigated the feasibility of contrast enhanced (CE)-dynamic magnetic resonance imaging (MRI) for the detection of testicular torsion induced hypoperfusion in an experimental rat model. Adult Sprague-Dawley rats were subjected to unilateral testicular torsion of 360 or 720 degrees. After 1 h, the tail veins of the anaesthetized rats were cannulated and T2 -, diffusion-weighted and T1-weighted CE-dynamic MRI were subsequently performed by a 1.5 T MRI scanner. On apparent diffusion coefficient (ADC) images, the region of interest values of the ischaemic and control testes was compared. From CE-dynamic MR images, the maximal slopes of contrast enhancement were calculated and compared. In testicular torsion of 360 degrees, the maximal slope of contrast enhancement was 0.072%/s vs. 0.47%/s in the contralateral control testis (p < 0.001). A torsion of 720 degrees diminished the slope of contrast enhancement to 0.046%/s vs. 0.37%/s in the contralateral testis (p < 0.001). Diminished blood flow during torsion also followed in decreased ADC values in both 360 degrees (12.4% decrease; p < 0.05) and 720 degrees (10.8% decrease; p < 0.001) of torsion. Torsion of the testis causes ipsilateral hypoperfusion and decreased gadolinium uptake in a rat model that can be easily detected and quantified by CE-dynamic MRI. In diffusion-weighted MRI images, acute hypoperfusion results in a slight decrease of ADC values. Our results suggest that CE-dynamic MRI in combination with diffusion-weighted MRI can be used to detect compromised blood flow due to acute testicular torsion.

  17. 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.

  18. Torsion and geometrostasis in covariant superstrings

    SciTech Connect

    Zachos, C.

    1985-01-01

    The covariant action for freely propagating heterotic superstrings consists of a metric and a torsion term with a special relative strength. It is shown that the strength for which torsion flattens the underlying 10-dimensional superspace geometry is precisely that which yields free oscillators on the light cone. This is in complete analogy with the geometrostasis of two-dimensional sigma-models with Wess-Zumino interactions. 13 refs.

  19. 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.

  20. Peripheral nerve palsy by torsional nerve injury.

    PubMed

    Guerra, Waltraud Kleist-Welch; Schroeder, Henry W S

    2011-04-01

    Peripheral nerve palsy caused by torsional nerve injury is rare. Only a few patients have been reported in the literature. The etiology of this type of nerve lesion is poorly understood. To report on 5 patients presenting with peripheral nerve palsy caused by a torsional nerve injury. Five patients presented with 6 upper peripheral nerve palsy involving the axillary nerve (n = 2), musculocutaneous nerve (n = 2), radial nerve (n = 1), and suprascapular nerve (n = 1). There was no history of trauma in 3 patients, but in the other 2 patients, nerve palsy occurred after a traumatic event. Because of a lack of spontaneous recovery, surgical exploration was performed. Torsion of the whole nerve (n = 5) or only 1 fascicle (n = 1) was found. Epifascicular epineurectomy and detorsion, as well as resection of the torsion site with subsequent primary nerve suture, were performed in 3 lesions. Good to excellent recovery of motor function was achieved in all 5 patients. In the last patient who presented with 2 nerve torsions, the follow-up period after the last surgery is too short to allow evaluation. Although not a frequent event, torsional nerve injury should be taken into consideration when dealing with peripheral nerve injuries. Surgical exploration with detorsion or suture results in good recovery.

  1. Torsional Optomechanics of a Levitated Nonspherical Nanoparticle

    NASA Astrophysics Data System (ADS)

    Hoang, Thai M.; Ma, Yue; Ahn, Jonghoon; Bang, Jaehoon; Robicheaux, F.; Yin, Zhang-Qi; Li, Tongcang

    2016-09-01

    An optically levitated nanoparticle in vacuum is a paradigm optomechanical system for sensing and studying macroscopic quantum mechanics. While its center-of-mass motion has been investigated intensively, its torsional vibration has only been studied theoretically in limited cases. Here we report the first experimental observation of the torsional vibration of an optically levitated nonspherical nanoparticle in vacuum. We achieve this by utilizing the coupling between the spin angular momentum of photons and the torsional vibration of a nonspherical nanoparticle whose polarizability is a tensor. The torsional vibration frequency can be 1 order of magnitude higher than its center-of-mass motion frequency, which is promising for ground state cooling. We propose a simple yet novel scheme to achieve ground state cooling of its torsional vibration with a linearly polarized Gaussian cavity mode. A levitated nonspherical nanoparticle in vacuum will also be an ultrasensitive nanoscale torsion balance with a torque detection sensitivity on the order of 10-29 N m /√{Hz } under realistic conditions.

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. 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

  7. 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.

  8. Torsional frequency mixing and sensing in optomechanical resonators

    NASA Astrophysics Data System (ADS)

    Huang, J. G.; Cai, H.; Gu, Y. D.; Chin, L. K.; Wu, J. H.; Chen, T. N.; Yang, Z. C.; Hao, Y. L.; Liu, A. Q.

    2017-09-01

    In this letter, a torsional optomechanical resonator for torque sensing and torsional mechanical frequency mixing is experimentally demonstrated. The torsional mechanical resonator is embedded into a split optical racetrack resonator, which provides high sensitivity in measuring torsional mechanical motion. Using this high sensitivity, torsional mechanical frequency mixing is observed without regenerative mechanical motion. The displacement noise floor of the torsional mechanical resonator is 50 fm/Hz0.5, which demonstrates a resonant torque sensitivity of 3.58 × 10-21 N m/Hz0.5. This demonstration will benefit potential applications for on-chip RF signal modulation using optical mechanical resonators.

  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.

  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. Torsional wave propagation in solar tornadoes

    NASA Astrophysics Data System (ADS)

    Vasheghani Farahani, S.; Ghanbari, E.; Ghaffari, G.; Safari, H.

    2017-02-01

    Aims: We investigate the propagation of torsional waves in coronal structures together with their collimation effects in the context of magnetohydrodynamic (MHD) theory. The interplay of the equilibrium twist and rotation of the structure, e.g. jet or tornado, together with the density contrast of its internal and external media is studied to shed light on the nature of torsional waves. Methods: We consider a rotating magnetic cylinder embedded in a plasma with a straight magnetic field. This resembles a solar tornado. In order to express the dispersion relations and phase speeds of the axisymmetric magnetohydrodynamic waves, the second-order thin flux tube approximation is implemented for the internal medium and the ideal MHD equations are implemented for the external medium. Results: The explicit expressions for the phase speed of the torsional wave show the modification of the torsional wave speed due to the equilibrium twist, rotation, and density contrast of the tornado. The speeds could be either sub-Alfvénic or ultra-Alfvénic depending on whether the equilibrium twist or rotation is dominant. The equilibrium twist increases the phase speed while the equilibrium rotation decreases it. The good agreement between the explicit versions for the phase speed and that obtained numerically proves adequate for the robustness of the model and method. The density ratio of the internal and external media also play a significant role in the speed and dispersion. Conclusions: The dispersion of the torsional wave is an indication of the compressibility of the oscillations. When the cylinder is rotating or twisted, in contrast to when it only possesses a straight magnetic field, the torsional wave is a collective mode. In this case its phase speed is determined by the Alfvén waves inside and outside the tornado.

  12. [Diagnosis and treatment for postoperative lobar torsion].

    PubMed

    Li, Hou-huai; Zhang, Qing-zhen; Xu, Lin; Chen, Liang; Wei, Yong-xiang; Wang, Yong-hong

    2007-07-17

    To analyze retrospectively 8 cases of postoperative lobar torsion after thoracotomy. 8 cases of postoperative lobar torsion were collected (5 men and 3 women; median age, 55.0 +/- 7.7 years), including lobectomy 4 (left upper lobe of lung 2, right upper lobe of lung 2), esophageal carcinosectomy 2, resection of schwannoma in the right upper mediastinum 1, and descending aorta replacement 1. The postoperative lobar torsions were right middle lobe 2, right upper lobe 1, left upper lobe 3, left lower lobe 1, left lung 1. The median peak temperature was 38.4 degrees C (range, 37.8 - 40.2 degrees C) and the median white blood cell count was 10.6 x 10(9) cells/L (range, 9.3 - 14.9 x 10(9) cell/L) during the first 48 hours postoperatively. Postoperative radiographs demonstrated pulmonary infiltrates and volume loss in 6 patients and complete opacification in 2 patients. The diagnosis of lobar torsion was made a median of 4 days (range, 2 - 14 days) after the initial operation; 6 patients underwent resection of lung and recovered; 2 had the injured lobe or lung rotated and died. Complications after reoperation included respiratory failure in 2 patients, atrial arrhythmia in 2 patients. Median hospitalization was 24 days and range from 10 to 56 days. The mobilization of hilus of lung or residual pulmonary atelectasis is the main mechanism of the lobar torsion after thoracotomy. Lobar torsion represents a difficult diagnostic dilemma in the early postoperative period after thoracotomy. Exploratory thoracotomy must be performed without delay. The injured parenchyma should be sacrificed unless the diagnosis is obtained very early. When the injured lobe or lung is rotated back into normal position, simultaneous endotracheal suction is very important to prevent aspiration of fluid from the obstructed part of the bronchial tree to the uninvolved segments and dangerous postoperative hypoxia.

  13. Torsional Behavior of Axonal Microtubule Bundles

    PubMed Central

    Lazarus, Carole; Soheilypour, Mohammad; Mofrad, Mohammad R.K.

    2015-01-01

    Axonal microtubule (MT) bundles crosslinked by microtubule-associated protein (MAP) tau are responsible for vital biological functions such as maintaining mechanical integrity and shape of the axon as well as facilitating axonal transport. Breaking and twisting of MTs have been previously observed in damaged undulated axons. Such breaking and twisting of MTs is suggested to cause axonal swellings that lead to axonal degeneration, which is known as “diffuse axonal injury”. In particular, overstretching and torsion of axons can potentially damage the axonal cytoskeleton. Following our previous studies on mechanical response of axonal MT bundles under uniaxial tension and compression, this work seeks to characterize the mechanical behavior of MT bundles under pure torsion as well as a combination of torsional and tensile loads using a coarse-grained computational model. In the case of pure torsion, a competition between MAP tau tensile and MT bending energies is observed. After three turns, a transition occurs in the mechanical behavior of the bundle that is characterized by its diameter shrinkage. Furthermore, crosslink spacing is shown to considerably influence the mechanical response, with larger MAP tau spacing resulting in a higher rate of turns. Therefore, MAP tau crosslinking of MT filaments protects the bundle from excessive deformation. Simultaneous application of torsion and tension on MT bundles is shown to accelerate bundle failure, compared to pure tension experiments. MAP tau proteins fail in clusters of 10–100 elements located at the discontinuities or the ends of MT filaments. This failure occurs in a stepwise fashion, implying gradual accumulation of elastic tensile energy in crosslinks followed by rupture. Failure of large groups of interconnecting MAP tau proteins leads to detachment of MT filaments from the bundle near discontinuities. This study highlights the importance of torsional loading in axonal damage after traumatic brain injury

  14. Torsion system for creep testing with multiple stress reversals

    NASA Technical Reports Server (NTRS)

    Lilienthal, P. A.

    1969-01-01

    Torsion system proves exploratory data on accelerated creep due to multiple stress reversals. Torsional testing of tubular specimens is best suited for reversed stress creep tests since large strains are obtainable while maintaining specimen geometry.

  15. Helioseismic measurement of solar torsional oscillations.

    PubMed

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

    2002-04-05

    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.

  16. Acute torsion of a wandering spleen.

    PubMed

    Lam, Y; Yuen, Kenny K Y; Chong, L C

    2012-04-01

    The 'wandering spleen' is a rare condition due to extreme laxity or absence of ligaments that fix the organ in its normal anatomical position within the left upper quadrant. Without early surgical intervention, wandering spleen can lead to torsion and subsequent splenic infarction or rupture. Clinical suspicion plus urgent investigation and intervention are important, so as to salvage the spleen and prevent complications. We present a case of torsion of a wandering spleen in a 21-year-old young woman, who presented with a painful pelvic mass. We also reviewed the literature on this entity.

  17. Wandering spleen with torsion and complete infarction.

    PubMed

    Chu, Jianping; Li, Ziping; Luo, Boning; Yang, Jianyong

    2011-10-01

    Wandering spleen is rare and is associated with a high incidence of splenic torsion and infarction. Presenting symptoms range from an asymptomatic, incidentally palpated abdominal mass to an acutely ill patient. Because wandering spleen is uncommon in the pediatric population, a heightened awareness of the condition is required for accurate diagnosis and appropriate management. We present a case of a 4-year-old girl who presented with acute abdomen and was surgically confirmed to have a wandering spleen with torsion and complete infarction.

  18. Acute Scrotum Caused by Hernia Sac Torsion.

    PubMed

    Fukui, Shinji; Aoki, Katsuya; Shimada, Keiji; Samma, Shoji

    2016-03-01

    A 9-year-old boy was referred to us with an acute pain attack of the left scrotal contents. Ultrasonography showed a normal blood supply to the left testis, suggesting an incarcerated left inguinal hernia. Surgical exploration did not demonstrate an incarcerated left inguinal hernia. After exploration of the left testis, a dark red pedunculated cystic mass, separate from the left testis, was found to be twisted. Immunohistochemical studies of the excised cyst demonstrated torsion of the hernia sac of the peritoneum. In conclusion, we encountered a case of acute scrotum which was probably caused by torsion of the hernia sac.

  19. Improved Coating System for High Strength Torsion Bars

    DTIC Science & Technology

    1981-04-23

    SwW IMPROVED COATING SYSTEM FOR HIGH S- TYPE Of REPORT & PEROo CovERED STRENGTH TORSION BAR Final Report Plastisol Coating System Provides a Cost...8217 mumber) Torsion Bar Plastisol Coating Inorganic Coating Protective Coating Polyvinyl Chloride Coating Polyurethane Coating Corrosion Protection Tape...Bars E. Endurance Test Results for One-third Length Torsion E-1 Bar F. Specification for Application of Plastisol to High F-1 Strength Torsion Bar

  20. Electrophysiological evaluation of cremasteric reflex in experimental testicular torsion.

    PubMed

    Soyer, T; Tosun, A; Somuncu, S; Aydin, G; Akman, H; Inal, E; Kanmaz, T; Cakmak, M

    2007-08-01

    The aim of the study was the electrophysiological evaluation of the cremasteric reflex after experimental testicular torsion. Ten male Wistar rats were enrolled into the study. Genitofemoral nerve (GFN) motor conduction and cremasteric reflex (CR) responses were evaluated electrophysiologically after being subjected to anesthesia with intramuscular ketamin hydrochloride. Testicular torsion was performed by rotating the right testicle 720 degrees in a clockwise direction from a midscrotal incision. Electrophysiological evaluations were repeated in the early (30 minutes) and late (90 minutes) periods of testicular torsion. Subsequently, detorsion of the testicles was performed and electrophysiological recordings were completed after 60 minutes of detorsion. The CR was also evaluated clinically before each electrophysiological evaluation. The latency and duration of GFN motor conduction and CR responses was compared for base, early torsion, late torsion and detorsion recordings. Friedman's test for repeated measurements was used for statistical analysis. The CR, which was detected clinically before torsion and after detorsion, was not detected during torsion. When base, early torsion, late torsion and detorsion recordings were compared, there was no statistical difference with respect to both latency and duration of GFN motor conduction and CR responses (p > 0.05). Although CR was not detected clinically during testicular torsion, the electrophysiological parameters of the reflex did not differ in the early and late periods of torsion in rats. The GFN motor conduction parameters also showed no differences. In conclusion, the absence of the CR after testicular torsion could not be confirmed by electrophysiological studies.

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

    PubMed

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

    2011-06-01

    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.

  2. 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)

  3. 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)

  4. Inferior alveolar nerve paresthesia relieved by microscopic endodontic treatment.

    PubMed

    Yatsuhashi, Takaaki; Nakagawa, Kan-Ichi; Matsumoto, Miho; Kasahara, Masataka; Igarashi, Tomoko; Ichinohe, Tatsuya; Kaneko, Yuzuru

    2003-11-01

    We experienced two cases of inferior alveolar nerve paresthesia caused by root canal medicaments, which were successfully relieved by microscopic endodontic treatment. In the first case, the paresthesia might have been attributable to infiltration of calcium hydroxide into the mandibular canal through the root canals of the mandibular left second molar tooth. In the second case, the paresthesia might have been attributable to infiltration of paraformaldehyde through the root canals of the mandibular right second molar tooth. The paresthesia was relieved in both cases by repetitive microscopic endodontic irrigation using physiological saline solution in combination with oral vitamin B12 and adenosine triphosphate.

  5. Plant-based torsional actuator with memory

    Treesearch

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

    2013-01-01

    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-...

  6. 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

  7. Clinical Characteristics of Torsion of the Omentum

    PubMed Central

    Montiel-Jarquin, Alvaro; Lopez-Colombo, Aurelio; Nava, Arnulfo; Juarez-Santiesteban, Rayo; Leyva-Trejo, Hugo; Zamora-Ustaran, Alfonso; García-Carrasco, Mario; Munoz-Guarneros, Margarita

    2009-01-01

    Background The aim of this paper is to describe clinical aspects of the torsion of the omentum. Methods In this observational, retrospective study, the study group consisted of patients surgically managed for torsion of the omentum, between 1998 and 2008, in a second level medical facility in Mexico. Variables in the study included age, sex, signs and symptoms, body mass index (BMI), treatment and evolution time. Descriptive statistical analysis was employed. Results Eleven patients were confirmed torsion of omentum, 7 (63.63%) women and 4 (36.36%) men, median age 33 (20 to 58) years, BMI > 25.0 in 9 (81.81%), average evolution 6.54, SD 3.47 days. All presented with abdominal pain, 6 (54.54%) with abdominal distension, 4 (36.36%) with ambulatory difficulty, 3 (27.27%) with malaise, and 5 (45.45%) with previous surgery. In all cases diagnosis was made by means of laparotomy, treatment was the resection of the affected segment, and there were no further complications. Conclusions Torsion of the omentum resembles acute appendicitis; abdominal pain and abdominal distension are the most common symptoms. It is often discovered during surgery and it is treated surgically by removal of the affected segment of the omentum. PMID:27942278

  8. Dispensing system eliminates torsion in deployed hoses

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Dispensing system uses a rotating drum, transfer arm, and stationary drum to deploy, reel in, and store an attached hose. This system which eliminates torsion and minimizes strain and wear of flexible hoses, is used for handling flexible cables that have one end permanently attached to an outlet or connector.

  9. Pseudotopological quasilocal energy of torsion gravity

    NASA Astrophysics Data System (ADS)

    Ko, Sheng-Lan; Lin, Feng-Li; Ning, Bo

    2017-08-01

    Torsion gravity is a natural extension to Einstein gravity in the presence of fermion matter sources. In this paper we adopt Wald's covariant method of calculating the Noether charge to construct the quasilocal energy of the Einstein-Cartan-fermion system, and find that its explicit expression is formally independent of the coupling constant between the torsion and axial current. This seemingly topological nature is unexpected and is reminiscent of the quantum Hall effect and topological insulators. However, a coupling dependence does arise when evaluating it on shell, and thus the situation is pseudotopological. Based on the expression for the quasilocal energy, we evaluate it for a particular solution on the entanglement wedge and find agreement with the holographic relative entropy obtained before. This shows the equivalence of these two quantities in the Einstein-Cartan-fermion system. Moreover, the quasilocal energy in this case is not always positive definite, and thus it provides an example of a swampland in torsion gravity. Based on the covariant Noether charge, we also derive the nonzero fermion effect on the Komar angular momentum. The implications of our results for future tests of torsion gravity in gravitational-wave astronomy are also discussed.

  10. Torsional ultrasound mode versus combined torsional and conventional ultrasound mode phacoemulsification for eyes with hard cataract

    PubMed Central

    Fakhry, Mohamed A; Shazly, Malak I El

    2011-01-01

    Purpose To compare torsional versus combined torsional and conventional ultrasound modes in hard cataract surgery regarding ultrasound energy and time and effect on corneal endothelium. Settings Kasr El Aini hospital, Cairo University, and International Eye Hospital, Cairo, Egypt. Methodology Ninety-eight eyes of 63 patients were enrolled in this prospective comparative randomized masked clinical study. All eyes had nuclear cataracts of grades III and IV using the Lens Opacities Classification System III (LOCS III). Two groups were included, each having an equal number of eyes (49). The treatment for group A was combined torsional and conventional US mode phacoemulsification, and for group B torsional US mode phacoemulsification only. Pre- and post-operative assessments included best corrected visual acuity (BCVA), intraocular pressure (IOP), slit-lamp evaluation, and fundoscopic evaluation. Endothelial cell density (ECD) and central corneal thickness (CCT) were measured preoperatively, 1 day, 7 days, and 1 month postoperatively. All eyes were operated on using the Alcon Infiniti System (Alcon, Fort Worth, TX) with the quick chop technique. All eyes were implanted with AcrySof SA60AT (Alcon) intraocular lens (IOL). The main phaco outcome parameters included the mean ultrasound time (UST), the mean cumulative dissipated energy (CDE), and the percent of average torsional amplitude in position 3 (%TUSiP3). Results Improvement in BCVA was statistically significant in both groups (P < 0.001). Comparing UST and CDE for both groups revealed results favoring the pure torsional group (P = 0.002 and P < 0.001 for UST; P = 0.058 and P = 0.009 for CDE). As for %TUSiP3, readings were higher for the pure torsional group (P = 0.03 and P = 0.01). All changes of CCT, and ECD over time were found statistically significant using one-way ANOVA testing (P < 0.001). Conclusion Both modes are safe in hard cataract surgery, however the pure torsional mode showed less US energy used. PMID

  11. Ultrasonography of Extravaginal Testicular Torsion in Neonates

    PubMed Central

    Bombiński, Przemysław; Warchoł, Stanisław; Brzewski, Michał; Majkowska, Zofia; Dudek-Warchoł, Teresa; Żerańska, Maria; Panek, Małgorzata; Drop, Magdalena

    2016-01-01

    Summary Background Extravaginal testicular torsion (ETT), also called prenatal or perinatal, occurs prenatally and is present at birth or appears within the first month of life. It has different etiology than intravaginal torsion, which appears later in life. Testicular torsion must be taken into consideration in differential diagnosis of acute scrotum and should be confirmed or ruled out at first diagnostic step. Ultrasonography is a basic imaging modality, however diagnostic pitfalls are still possible. There is still wide discussion concerning management of ETT, which varies from immediate orchiectomy to conservative treatment resulting in testicle atrophy. Material/Methods In this article we present ultrasonographic spectrum of ETT in neonates, which were diagnosed and treated in our hospital during the last 8 years (2008–2015), in correlation with clinical and intraoperative findings. Results Thirteen neonates with ETT were enrolled in the study – 11 patients with a single testicle affected and 2 patients with bilateral testicular torsion. Most common signs on clinical examination were: hardened and enlarged testicle and discoloration of the scrotum. Most common ultrasonographic signs were: abnormal size or echostructure of the affected testicle and absence of the blood flow in Doppler ultrasonography. In 3 patients ultrasound elastography was performed, which appeared very useful in testicle structure assessment. Conclusions Testicular torsion may concern boys even in the perinatal period. Ultrasonographic picture of acute scrotum in young boys may be confused. Coexistence of the abnormal size or echostructure of the torsed testicle with absence of the blood flow in Doppler ultrasonography appear as very specific but late ultrasonographic sings. Ultrasound elastography may be a very useful tool for visualisation of a very common clinical sign – hardening of the necrotic testicle. PMID:27757176

  12. Torsion of an intra-abdominal testis.

    PubMed

    Lewis; Roller; Parra; Cotlar

    2000-09-01

    To present a case of torsion of a nonneoplastic intra-abdominal testis with an unusual clinical presentation.A 26-year-old active duty Navy Petty Officer presented to the emergency department on 3 occasions over a 5-day period with lower abdominal pain. Physical examination demonstrated acute tenderness in the left lower quadrant with sugestion of a normal spermatic cord and atrophic testis in the left scrotum. Computed tomography scan demonstrated an intra-abdominal lesion near the internal inguinal ring. The patient underwent surgical exploration through an inguinal incision. Torsion of a nonviable intra-abdominal testis was present. The scrotum contained only the vas deferens and cremasteric muscle. An orchiectomy was performed with removal of the vas deferens and other cord structures.The unusual clinical finding of acute torsion of an intra-abdominal testis, associated with an apparent atrophic scrotal testis, presented a confusing clinical picture. Computed tomography scan did not clarify the issue sufficiently to establish a definite preoperative diagnosis. Clinical suspicion prompted early surgical intervention. Review of the current literature produced 60 reported cases of torsion of an intra-abdominal testis. Two thirds of these involved testicular neoplasm, usually seminoma. Although the clinical presentation varied, most patients had recent onset of lower abdominal pain associated with tenderness and, in half the cases, a mass. Patients almost always presented with an absent scrotal testis on the involved side, and not infrequently reported previous surgery thought to be an orchiectomy.Diagnosis of an intra-abdominal testicular torsion is rare, particularly when no neoplasm is present. A high index of suspicion must be maintained whenever there is abdominal pain and undescended testis. The surgical history and imaging studies may not clarify a confusing clinical picture.

  13. Torsion of a Large Appendix Testis Misdiagnosed as Pyocele

    PubMed Central

    Meher, Susanta; Rath, Satyajit; Sharma, Rakesh; Sasmal, Prakash Kumar; Mishra, Tushar Subhadarshan

    2015-01-01

    Torsion of the appendix testis is not an uncommon cause of acute hemiscrotum. It is frequently misdiagnosed as acute epididymitis, orchitis, or torsion of testis. Though conservative management is the treatment of choice for this condition, prompt surgical intervention is warranted when testicular torsion is suspected. We report a case of torsion of a large appendix testis misdiagnosed as pyocele. Emergency exploration of it revealed a large appendix testis with torsion and early features of gangrene. After excision of the appendix testis, the wound was closed with an open drain. The patient had an uneventful and smooth postoperative recovery. PMID:25861514

  14. 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.

  15. 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

  16. Precipitating and relieving factors of migraine versus tension type headache

    PubMed Central

    2012-01-01

    Background To determine the differences of precipitating and relieving factors between migraine and tension type headache. Methods This is a cross sectional study. We retrospectively reviewed the records of 250 migraine patients and 250 patients diagnosed as tension type headache from the specialized headache clinic in Dept. of Neurology, Dhaka Medical College Hospital. Data were collected through a predesigned questionnaire containing information on age, sex, social status and a predetermined list of precipitating and relieving factors. Results In this study, the female patients predominated (67%). Most of the patients were within 21–30 years age group (58.6%). About 58% of them belonged to middle class families. The common precipitating factors like stress, anxiety, activity, journey, reading, cold and warm were well distributed among both the migraine and tension type headache (TTH) patients. But significant difference was demonstrated for fatigue (p < 0.05), sleep deprivation (p < 0.05), sunlight (p < 0.01) and food (p < 0.05), which were common among migraineurs. In consideration of relieving factors of pain, different maneuvers were commonly tried by migraineurs and significant difference were observed for both analgesic drug and massage (p < 0.05), which relieved migraine headache. But maneuvers like sleep, rest and posture were used by both groups. Conclusion The most frequent precipitating factors for headache appear to be identical for both migraine and TTH patients. Even though some factors like fatigue, sleep deprivation, sunlight and food significantly precipitate migraine and drug, massage are effective maneuver for relieving pain among migrianeurs. PMID:22920541

  17. Precipitating and relieving factors of migraine versus tension type headache.

    PubMed

    Haque, Badrul; Rahman, Kazi Mohibur; Hoque, Azharul; Hasan, A T M Hasibul; Chowdhury, Rajib Nayan; Khan, Sharif Uddin; Alam, Mondal Badrul; Habib, Mansur; Mohammad, Quazi Deen

    2012-08-25

    To determine the differences of precipitating and relieving factors between migraine and tension type headache. This is a cross sectional study. We retrospectively reviewed the records of 250 migraine patients and 250 patients diagnosed as tension type headache from the specialized headache clinic in Dept. of Neurology, Dhaka Medical College Hospital. Data were collected through a predesigned questionnaire containing information on age, sex, social status and a predetermined list of precipitating and relieving factors. In this study, the female patients predominated (67%). Most of the patients were within 21-30 years age group (58.6%). About 58% of them belonged to middle class families. The common precipitating factors like stress, anxiety, activity, journey, reading, cold and warm were well distributed among both the migraine and tension type headache (TTH) patients. But significant difference was demonstrated for fatigue (p < 0.05), sleep deprivation (p < 0.05), sunlight (p < 0.01) and food (p < 0.05), which were common among migraineurs. In consideration of relieving factors of pain, different maneuvers were commonly tried by migraineurs and significant difference were observed for both analgesic drug and massage (p < 0.05), which relieved migraine headache. But maneuvers like sleep, rest and posture were used by both groups. The most frequent precipitating factors for headache appear to be identical for both migraine and TTH patients. Even though some factors like fatigue, sleep deprivation, sunlight and food significantly precipitate migraine and drug, massage are effective maneuver for relieving pain among migrianeurs.

  18. 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

  19. Chronic splenic torsion in two dogs.

    PubMed

    Reinhart, Jennifer M; Sherwood, J Matthew; KuKanich, Katherine S; Klocke, Emily; Biller, David S

    2015-01-01

    A 5 yr old spayed female poodle (case 1) was presented with a 4 mo history of lethargy, inappetence, and nonregenerative anemia. A 5 yr old castrated male French bulldog (case 2) was presented with a 2 wk history of mild abdominal pain, dyschezia, and intermittent anorexia. Both dogs were diagnosed with chronic splenic torsion based on changes in splenic position, echogenicity, and/or echotexture identified on B-mode abdominal ultrasonography, as well as either decreased or absent splenic blood flow on color-flow Doppler ultrasonography. Both dogs underwent splenectomy and had full resolution of clinical signs. Presentation of chronic splenic torsion is variable, and clinical signs can be nonspecific. Abdominal ultrasound with Doppler evaluation is an important diagnostic step that can lead to appropriate surgical intervention and good long-term prognosis.

  20. 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.

  1. 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.

  2. Investigation of the torsional stiffness of flexible disc coupling

    NASA Astrophysics Data System (ADS)

    Buryy, A.; Simonovsky, V.; Obolonik, V.

    2017-08-01

    Calculation of flexible coupling torsional stiffness is required when analyzing the torsional vibrations of the reciprocating machinery train. While having the lowest torsional stiffness of all the elements of the train, flexible coupling has a significant influence on the natural frequencies of torsional vibration. However, considering structural complexity of coupling, precise definition of its torsional stiffness is quite a difficult task. The paper presents a method for calculating the torsional stiffness of flexible disc coupling based on the study of its finite element model response under the action of torque. The analysis of the basic parameters that quantitatively and qualitatively affect the coupling torsional stiffness has been also provided. The results of the calculation as well as model adequacy, sufficient for practical application, have been confirmed at the experimental measurement of flexible disc coupling torsional stiffness. The obtained elastic characteristics (dependences of applied torque and torsional stiffness versus twist angle) are nonlinear in the initial stage of loading. This feature should be taken into account when creating reliable mathematical models of torsional vibrations of reciprocating machinery trains containing flexible disc couplings.

  3. Comparison of geometric torsion in scoliosis under Lenke classification.

    PubMed

    Zhang, Junhua; Lv, Liang

    2013-01-01

    The objective of this study is to investigate whether three dimensional (3D) variability exists within the Lenke classification, and to evaluate the correlations between the 3D features and the Cobb angle used in the Lenke classification. Forty-nine scoliotic patients with Lenke Type 1 curve were selected for analysis. For each patient, the 3D spine model was reconstructed from biplanar radiographs, and the geometric torsion was then calculated from the reconstructed spine model. An analysis of variance (ANOVA) was performed regarding the average torsion, the maximum torsion, and the Cobb angle, with the patients subdivided according to the torsion pattern. Results showed that a statistically significant difference was observed for the torsion parameters (i.e., the average torsion and the maximum torsion) between subgroups within the Lenke Type 1 curves while no statistically significant difference was found regarding the Cobb angle. The strengths of correlations between the torsion parameters and Cobb angle were stronger in the subgroup with torsion pattern of Type A. These results add the evidence that 3D geometric torsion reveals structural differences that are not apparent in the Cobb measurement.

  4. 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

  5. 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.

  6. 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)

  7. 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)

  8. Torsional Oscillations of Nonbare Strange Stars

    NASA Astrophysics Data System (ADS)

    Mannarelli, Massimo; Pagliaroli, Giulia; Parisi, Alessandro; Pilo, Luigi; Tonelli, Francesco

    2015-12-01

    Strange stars are one of the possible compact stellar objects that can form after a supernova collapse. We consider a model of a strange star having an inner core in the color-flavor locked phase surmounted by a crystalline color superconducting (CCSC) layer. These two phases constitute the quarksphere, which we assume to be the largest and heaviest part of the strange star. The next layer consists of standard nuclear matter forming an ionic crust, hovering on the top of the quarksphere and prevented from falling by a strong dipolar electric field. The dipolar electric field arises because quark matter is confined in the quarksphere by the strong interaction, but electrons can leak outside forming an electron layer a few hundred fermi thick separating the ionic crust from the underlying quark matter. The ionic matter and the CCSC matter constitute two electromagnetically coupled crust layers. We study the torsional oscillations of these two layers. Remarkably, we find that if a fraction larger than 10-4 of the energy of a Vela-like glitch is conveyed to a torsional oscillation, the ionic crust will likely break. The reason is that the very rigid and heavy CCSC crust layer will absorb only a small fraction of the glitch energy, leading to a large-amplitude torsional oscillation of the ionic crust. The maximum stress generated by the torsional oscillation is located inside the ionic crust and is very close to the star’s surface. This peculiar behavior leads to a much easier crust cracking than in standard neutron stars.

  9. Myocardial Rotation and Torsion in Child Growth

    PubMed Central

    Kim, Chang Sin; Park, Sora

    2016-01-01

    Background The speckle tracking echocardiography can benefit to assess the regional myocardial deformations. Although, previous reports suggested no significant change in left ventricular (LV) torsion with aging, there are certain differences in LV rotation at the base and apex. The purpose of this study was to evaluate the change and relationship of LV rotation for torsion with aging in children. Methods Forty healthy children were recruited and divided into two groups of twenty based on whether the children were preschool-age (2–6 years of age) or school-age (7–12 years of age). After obtaining conventional echocardiographic data, apical and basal short axis rotation were assessed with speckle tracking echocardiography. LV rotation in the basal and apical short axis planes was determined using six myocardial segments along the central axis. Results Apical and basal LV rotation did not show the statistical difference with increased age between preschool- and school-age children. Apical radial strain showed significant higher values in preschool-age children, especially at the anterior (52.8 ± 17.4% vs. 34.7 ± 23.2%, p < 0.02), lateral (55.8 ± 20.4% vs. 36.1 ± 22.7%, p < 0.02), and posterior segments (57.1 ± 17.6% vs. 38.5 ± 21.7%, p < 0.01). The torsion values did not demonstrate the statistical difference between two groups. Conclusion This study revealed the tendency of higher rotation values in preschool-age children than in school-age children. The lesser values of rotation and torsion with increased age during childhood warrant further investigation. PMID:27721953

  10. 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.

  11. TORSIONAL OSCILLATIONS OF NONBARE STRANGE STARS

    SciTech Connect

    Mannarelli, Massimo; Pagliaroli, Giulia; Parisi, Alessandro; Pilo, Luigi; Tonelli, Francesco

    2015-12-20

    Strange stars are one of the possible compact stellar objects that can form after a supernova collapse. We consider a model of a strange star having an inner core in the color-flavor locked phase surmounted by a crystalline color superconducting (CCSC) layer. These two phases constitute the quarksphere, which we assume to be the largest and heaviest part of the strange star. The next layer consists of standard nuclear matter forming an ionic crust, hovering on the top of the quarksphere and prevented from falling by a strong dipolar electric field. The dipolar electric field arises because quark matter is confined in the quarksphere by the strong interaction, but electrons can leak outside forming an electron layer a few hundred fermi thick separating the ionic crust from the underlying quark matter. The ionic matter and the CCSC matter constitute two electromagnetically coupled crust layers. We study the torsional oscillations of these two layers. Remarkably, we find that if a fraction larger than 10{sup −4} of the energy of a Vela-like glitch is conveyed to a torsional oscillation, the ionic crust will likely break. The reason is that the very rigid and heavy CCSC crust layer will absorb only a small fraction of the glitch energy, leading to a large-amplitude torsional oscillation of the ionic crust. The maximum stress generated by the torsional oscillation is located inside the ionic crust and is very close to the star’s surface. This peculiar behavior leads to a much easier crust cracking than in standard neutron stars.

  12. 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.

  13. Strain softening in stretched DNA

    PubMed Central

    Luan, Binquan; Aksimentiev, Aleksei

    2010-01-01

    The microscopic mechanics of DNA stretching was characterized using extensive molecular dynamics simulations. By employing an anisotropic pressure control method, realistic force-extension dependences of effectively infinite DNA molecules were obtained. A coexistence of B- and S-DNA domains was observed during the overstretching transition. The simulations revealed that strain softening may occur in the process of stretching torsionally constrained DNA. The latter observation was qualitatively reconciled with available experimental data using a random-field Ising model. PMID:18851334

  14. Neonatal testicular torsion: a systematic literature review.

    PubMed

    Nandi, Biplab; Murphy, Feilim Liam

    2011-10-01

    Neonatal testicular torsion (NTT) is rare and reported salvage rates vary widely both in their cited frequency and plausibility. The timing and necessity of surgery is controversial with different centers arguing for the conservative management of all cases while others argue for prompt exploration for all. Confusion also reigns over the need to fix the contralateral testis. In order to clarify the issue the authors reviewed the literature and found 18 case series of NTT, containing 268 operated cases suitable for analysis. This paper reviews the literature on NTT specifically regarding salvage rates and timing/necessity of surgery. Its primary aim is to produce an overall salvage rate in the operated group. Overall salvage rate was 8.96%, 24 testes. When operation is specified as an emergency, salvage may be as high as 21.7%. While salvage of a testis torted at birth is rare, it is reported. Early asynchronous torsion is also rare but reported. Worryingly, bilateral torsion can present with unilateral signs.Given these findings, we would suggest early surgery with fixation of the contralateral side.

  15. 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.

  16. Polyorchidism with presumed contralateral intrauterine testicular torsion

    PubMed Central

    Leodoro, B.M.; Beasley, S.W.; Stringer, M.D.

    2014-01-01

    INTRODUCTION Polyorchidism was first described by Blasius in 16701 during a routine autopsy. We report a child with unilateral polyorchidism and a contralateral absent testis, a combination not reported previously. PRESENTATION OF CASE A 2-year-old boy was referred to the outpatient clinic with an impalpable left testis. At laparoscopy, the left vas deferens and testicular vessels ended blindly proximal to a closed internal ring. No gonadal tissue was identified. On the right side, a single vas deferens and testicular vessels were seen entering the internal ring as normal. The right side of the scrotum was explored and two testes were identified within a single tunica vaginalis. DISCUSSION Polyorchidism is rare with a literature search identifying approximately 230 reported cases. Whilst prenatal testicular torsion is increasing being recognized and treated as a surgical emergency,9 prenatal testicular torsion in association with polyorchidism has not been previously reported. CONCLUSION We describe a unique case of a 2-year-old boy with right-sided polyorchidism and an absent left testis associated with a blind ending vas deferens and testicular vessels, presumed secondary to intrauterine testicular torsion. PMID:25462053

  17. Aeroelastic considerations for torsionally soft rotors

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

    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. Azimuthal variation of elastic twist generated by variations in the tip parameters strongly correlated with rotor performance and loads, but the magnitude of advancing blade elastic twist did not. In addition, fixed system vibratory loads and rotor track for potential conformable rotor candidates appears very sensitive to parametric rotor changes.

  18. Evaluation of the torsional VOR in weightlessness.

    PubMed

    Clarke, A H; Teiwes, W; Scherer, H

    1993-01-01

    The experimental concept and findings from a recent manned orbital spaceflight are described. Together with ongoing terrestrial and parabolic studies, the present experiment is intended to further our knowledge of the sensory integrative processing of information from the semicircular canals and the otolithic receptors, and to quantify the presumed otolithic adaptation to altered gravito-inertial force environments in a more reliable manner than to date. The experiment included measurement of the basic vestibulo-oculomotor response during active head rotation about each of the three orthogonal axes. Priority was given to the recording of ocular torsion, as elicited by head oscillation about the roll axis, and thus due to the concomitant stimulation of the semicircular canals and otolith receptors. Videooculography was employed for the measurement of eye movements; head movement was measured by three orthogonally arranged angular rate sensors and a triaxial linear accelerometer device. All signals were recorded synchronously on a video/data recorder. Preliminary results indicate alterations in the torsional VOR under zero-g conditions, suggesting an adaptive modification of the torsional VOR gain over the course of the 6-day orbital flight. In addition, the inflight test findings yielded discrepancies between intended and performed head movement, indicating impairment in sensorimotor coordination under prolonged microgravity conditions.

  19. 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.

  20. Big bounce from spin and torsion

    NASA Astrophysics Data System (ADS)

    Popławski, Nikodem J.

    2012-04-01

    The Einstein-Cartan-Sciama-Kibble theory of gravity naturally extends general relativity to account for the intrinsic spin of matter. Spacetime torsion, generated by spin of Dirac fields, induces gravitational repulsion in fermionic matter at extremely high densities and prevents the formation of singularities. Accordingly, the big bang is replaced by a bounce that occurred when the energy density {ɛ ∝ gT^4} was on the order of {n^2/m_Pl^2} (in natural units), where {n ∝ gT^3} is the fermion number density and g is the number of thermal degrees of freedom. If the early Universe contained only the known standard-model particles ( g ≈ 100), then the energy density at the big bounce was about 15 times larger than the Planck energy. The minimum scale factor of the Universe (at the bounce) was about 1032 times smaller than its present value, giving ≈ 50 μm. If more fermions existed in the early Universe, then the spin-torsion coupling causes a bounce at a lower energy and larger scale factor. Recent observations of high-energy photons from gamma-ray bursts indicate that spacetime may behave classically even at scales below the Planck length, supporting the classical spin-torsion mechanism of the big bounce. Such a classical bounce prevents the matter in the contracting Universe from reaching the conditions at which a quantum bounce could possibly occur.

  1. Torsional Network Model: Normal Modes in Torsion Angle Space Better Correlate with Conformation Changes in Proteins

    NASA Astrophysics Data System (ADS)

    Mendez, Raul; Bastolla, Ugo

    2010-06-01

    We introduce the torsional network model (TNM), an elastic network model whose degrees of freedom are the torsion angles of the protein backbone. Normal modes of the TNM displace backbone atoms including Cβ maintaining their covalent geometry. For many proteins, low frequency TNM modes are localized in torsion space yet collective in Cartesian space, reminiscent of hinge motions. A smaller number of TNM modes than anisotropic network model modes are enough to represent experimentally observed conformation changes. We observed significant correlation between the contribution of each normal mode to equilibrium fluctuations and to conformation changes, and defined the excess correlation with respect to a simple neutral model. The stronger this excess correlation, the lower the predicted free energy barrier of the conformation change and the fewer modes contribute to the change.

  2. 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.

  3. 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

  4. 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

  5. An anatomical measurement of medial femoral torsion.

    PubMed

    Kim, Ha Y; Lee, Sang K; Lee, Neung K; Choy, Won S

    2012-11-01

    Medial femoral torsion (MFT) can be corrected with derotational osteotomy. Derotational osteotomies can be performed in the proximal or the distal part of the femur. Similar results have been reported for these two procedures. The aim of this study was to evaluate the pathologic location of the MFT by measuring the degree of infratrochanteric and supratrochanteric torsion (STT) of the femur using computed tomography (CT) scans. The current study was carried out in patients with the chief complaint of an in-toeing gait because of the MFT. Sixty-seven patients were enrolled in the study. Forty-one patients (72 lower extremities) were included in the intervention group; 20 patients were included in the cerebral palsy (CP) group (35 lower extremities) and 21 patients were included in the developmental MFT group [developmental femoral torsional (DF) group, 37 lower extremities]. The control group included 26 patients (33 lower extremities) with uninjured limbs with a femoral or a tibial fracture. In this study, torsional angles [MFT, STT and infratrochanteric torsion (ITT)] were measured on CT scan using picture archiving and communication system measurement tools. To measure the STT and ITT, the most prominent points of the lesser and the greater trochanter were marked on CT scans; these two points were connected and were defined as the intertrochanteric line (ITL). The angle between the ITL and the axis of the femoral neck was defined as the STT. The angle between the ITL and the axis of the condylar axis was defined as the ITT. Two authors measured the MFT, STT, and ITT angles of each femur independently. The twisting of the femur had occurred in a different location for each case. In all groups, however, STT was reduced with increasing age; this change was statistically significantly. ITT of the each group showed a random distribution. The means of the ITT in the control group and the DF group did not change significantly, and that of the CP group tended to decrease

  6. Design of a nonlinear torsional vibration absorber

    NASA Astrophysics Data System (ADS)

    Tahir, Ammaar Bin

    Tuned mass dampers (TMD) utilizing linear spring mechanisms to mitigate destructive vibrations are commonly used in practice. A TMD is usually tuned for a specific resonant frequency or an operating frequency of a system. Recently, nonlinear vibration absorbers attracted attention of researchers due to some potential advantages they possess over the TMDs. The nonlinear vibration absorber, or the nonlinear energy sink (NES), has an advantage of being effective over a broad range of excitation frequencies, which makes it more suitable for systems with several resonant frequencies, or for a system with varying excitation frequency. Vibration dissipation mechanism in an NES is passive and ensures that there is no energy backflow to the primary system. In this study, an experimental setup of a rotational system has been designed for validation of the concept of nonlinear torsional vibration absorber with geometrically induced cubic stiffness nonlinearity. Dimensions of the primary system have been optimized so as to get the first natural frequency of the system to be fairly low. This was done in order to excite the dynamic system for torsional vibration response by the available motor. Experiments have been performed to obtain the modal parameters of the system. Based on the obtained modal parameters, the design optimization of the nonlinear torsional vibration absorber was carried out using an equivalent 2-DOF modal model. The optimality criterion was chosen to be maximization of energy dissipation in the nonlinear absorber attached to the equivalent 2-DOF system. The optimized design parameters of the nonlinear absorber were tested on the original 5-DOF system numerically. A comparison was made between the performance of linear and nonlinear absorbers using the numerical models. The comparison showed the superiority of the nonlinear absorber over its linear counterpart for the given set of primary system parameters as the vibration energy dissipation in the former is

  7. [Clinical research of music in relieving orthodontic pain].

    PubMed

    Xu, Xiaomei; Zhang, Lihua; Jiang, Yahua; Huang, Yue; Huang, Suhua; Yang, Siwei

    2013-08-01

    To discuss the effect of music in relieving pain during orthodontic treatment. One hundred and sixty-five cases who wore arches the first time were selected and treated. These patients were randomly divided into two groups: Music group and blank group. The music intervention was used in reducing orthodontic treatment pain, while blank group experienced no intervention measures. Visual analogue scales (VAS) were adopted to record patients' perception of pain, and Eysenck personality questionnaire (EPQ) to evaluate personality traits of all samples. In 165 patients, 85.45% were effective. The music group showed significantly less pain than the blank group (P < 0.05). In music and blank group, the pain was stronger in the patients with a tendency of introversion than those with a tendency of extroversion, as well as the irritability ones than steady-minded (P < 0.05). In music group, the pain was stronger in the females than the males (P < 0.05). Music helps to relieve pain during orthodontics treatment. The effect of music to relieve the pain during orthodontics treatment for the males are better than that for the females, extroverted personality ones are superior to introversive personality ones, and the steady-minded patients are better than irritability ones.

  8. DNA supercoiling and its role in DNA decatenation and unknotting

    PubMed Central

    Witz, Guillaume; Stasiak, Andrzej

    2010-01-01

    Chromosomal and plasmid DNA molecules in bacterial cells are maintained under torsional tension and are therefore supercoiled. With the exception of extreme thermophiles, supercoiling has a negative sign, which means that the torsional tension diminishes the DNA helicity and facilitates strand separation. In consequence, negative supercoiling aids such processes as DNA replication or transcription that require global- or local-strand separation. In extreme thermophiles, DNA is positively supercoiled which protects it from thermal denaturation. While the role of DNA supercoiling connected to the control of DNA stability, is thoroughly researched and subject of many reviews, a less known role of DNA supercoiling emerges and consists of aiding DNA topoisomerases in DNA decatenation and unknotting. Although DNA catenanes are natural intermediates in the process of DNA replication of circular DNA molecules, it is necessary that they become very efficiently decatenated, as otherwise the segregation of freshly replicated DNA molecules would be blocked. DNA knots arise as by-products of topoisomerase-mediated intramolecular passages that are needed to facilitate general DNA metabolism, including DNA replication, transcription or recombination. The formed knots are, however, very harmful for cells if not removed efficiently. Here, we overview the role of DNA supercoiling in DNA unknotting and decatenation. PMID:20026582

  9. Interplay between DNA supercoiling and transcription elongation.

    PubMed

    Ma, Jie; Wang, Michelle

    2014-01-01

    Transcription-coupled DNA supercoiling has been shown to be an important regulator of transcription that is broadly present in the cell. Here we review experimental work which shows that RNA polymerase is a powerful torsional motor that can alter DNA topology and structure, and DNA supercoiling in turn directly affects transcription elongation.

  10. Missed Spermatic Cord Torsion in an Old Man

    PubMed Central

    Seo, Yu Mi; Myung, Na-Hye

    2013-01-01

    The fate of testicular salvage in spermatic cord torsion depends on the duration of ischemia and the degree of torsion. Even though spermatic cord torsion (SCT) can occur at any age, it is rarely reported in older patients. If the physician does not pay close attention to this unusual situation, the lack of suspicion for SCT may result in a missed or delayed diagnosis. We report a very uncommon case of missed SCT occurring in a 63-year-old man. PMID:24175049

  11. Torsion in wandering spleen: CT demonstration of whirl sign.

    PubMed

    Priyadarshi, Rajeev N; Anand, Utpal; Kumar, Bindey; Prakash, Vijay

    2013-08-01

    Wandering spleen is a rare occurrence. Torsion of the splenic pedicle is the major life-threatening complication of this entity. Preoperative diagnosis is based on radiological investigation. We report two consecutive cases, one adult and one child, in whom torsion in a wandering spleen was diagnosed based on a typical whirled appearance of the splenic vessels on computed tomography. We present a review of computed tomographic appearance of splenic torsion, and emphasize the "whirled appearance" as a specific sign for splenic torsion in wandering spleen.

  12. A novel approach for manual de-torsion of an atypical (outward) testicular torsion with bedside Doppler ultrasonography guidance.

    PubMed

    Güneş, Mustafa; Umul, Mehmet; Çelik, Ahmet Orhan; Armağan, Hamit Hakan; Değirmenci, Bumin

    2015-01-01

    A 17-year-old boy presented with right testicular torsion to the lateral side. Torsion was diagnosed by physical examination; the colour Doppler ultrasonography (CDU) confirmed right testicular torsion with minimal peripheral hydrocele. Transverse and longitudinal examination of the spermatic cord with ultrasound and CDU revealed a counter-clockwise testicular torsion. Manual de-torsion was performed in a clockwise direction (720o) and testicular blood flow and the neutral position of the spermatic cord were confirmed by CDU. We did not encounter a residual twist of the spermatic cord upon surgical exploration. In our experience, ultrasound and CDU may predict the direction of testicular torsion and may allow appropriate management of cases prior to surgery.

  13. A novel approach for manual de-torsion of an atypical (outward) testicular torsion with bedside Doppler ultrasonography guidance

    PubMed Central

    Güneş, Mustafa; Umul, Mehmet; Çelik, Ahmet Orhan; Armağan, Hamit Hakan; Değirmenci, Bumin

    2015-01-01

    A 17-year-old boy presented with right testicular torsion to the lateral side. Torsion was diagnosed by physical examination; the colour Doppler ultrasonography (CDU) confirmed right testicular torsion with minimal peripheral hydrocele. Transverse and longitudinal examination of the spermatic cord with ultrasound and CDU revealed a counter-clockwise testicular torsion. Manual de-torsion was performed in a clockwise direction (720o) and testicular blood flow and the neutral position of the spermatic cord were confirmed by CDU. We did not encounter a residual twist of the spermatic cord upon surgical exploration. In our experience, ultrasound and CDU may predict the direction of testicular torsion and may allow appropriate management of cases prior to surgery. PMID:26425241

  14. 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 ...

  15. 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

  16. Search for torsional oscillations in isolated sunspots

    NASA Astrophysics Data System (ADS)

    Griñón-Marín, A. B.; Socas-Navarro, H.; Centeno, R.

    2017-07-01

    In this work we seek evidence for global torsional oscillations in alpha sunspots. We have used long time series of continuum intensity and magnetic field vector maps from the Helioseismic and Magnetic Imager (HMI) instrument on board the Solar Dynamics Observatory (SDO) spacecraft. The time series analysed here span the total disk passage of 25 isolated sunspots. We found no evidence of global long-term periodic oscillations in the azimuthal angle of the sunspot magnetic field within 1 degree. This study could help us to understand the sunspot dynamics and its internal structure.

  17. Primary torsion of the greater omentum.

    PubMed

    Gul, Y A; Jabbar, M F; Moissinac, K

    2001-01-01

    Primary or idiopathic greater omental torsion remains a rare cause of acute surgical abdomen in adults and children. The aetiology is as yet unknown and the treatment of choice, once diagnosis is established, is resection of the torted omentum. We report our experience with three such cases encountered over the last five years, two of which were diagnosed and subsequently managed laparoscopically. The performance of diagnostic laparoscopy for acute abdominal pain of an undetermined origin may lead to an increased detection of this condition and subsequent therapeutic intervention.

  18. 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 suffering...

  19. 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.

  20. Torsion and bending of prismatic rods of hollow rectangular section

    NASA Technical Reports Server (NTRS)

    Abramyan, B L

    1951-01-01

    The torsion and bending of hollow rectangular beams was investigated without the requirement that wall thickness be small compared with the transverse dimensions. The limits of applicability of the usual Bredt formula are indicated for the case of a square hollow tube in torsion. Formulas are given for bending stresses at different parts of the cross section of a hollow rectangular beam.

  1. 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.

  2. Constraints on torsion from bounds on lorentz violation.

    PubMed

    Kostelecký, V Alan; Russell, Neil; Tasson, Jay D

    2008-03-21

    Exceptional sensitivity to space-time torsion can be achieved by searching for its couplings to fermions. Recent experimental searches for Lorentz violation are exploited to extract new constraints involving 19 of the 24 independent torsion components down to levels of order 10(-31) GeV.

  3. Five Year Retrospective Case Series of Adnexal Torsion

    PubMed Central

    Joy, Smitha; Nayar, Jayashree

    2014-01-01

    Aims and Objectives: Adnexal torsion is a rare gynaecological emergency that requires an early surgical intervention to save the adnexa from irreversible damage .Our study is about clinical presentation and management approach of adnexal torsion in a tertiary care centre. Study Design: Retrospective study. Materials and Methods: Review of case records during the five years of 2008 November -2013 November in Amrita Institute of Medical Sciences, Kochi, India. Results: Adnexal torsion was found mainly in the reproductive age. Ultrasound was the most commonly used imaging modality. Benign tumours predispose to torsion. Torsion occurred during postovulatory period in many cases. Polycystic ovaries were a risk factor for unexplained torsion in younger age groups. Diagnosis of adnexal torsion was mostly intra operative by direct visualisation of the rotated adnexa. Laparoscopy was the preferred method of surgical intervention. Ovarian conservation was tried in majority of the child bearing age groups. Conclusion: Adnexal torsion is a rare emergency which requires a high index of clinical suspicion for diagnosis as the symptoms are non specific. Imaging helps in diagnosis but most of them are diagnosed intra operatively. Laparoscopic conservative surgery is the preferred surgical approach especially in younger age groups. An early surgical intervention helps in salvaging the adnexa and prevents further complications. PMID:25653994

  4. Spontaneous nerve torsion: unusual cause of radial nerve palsy.

    PubMed

    Endo, Yoshimi; Miller, Theodore T; Carlson, Erik; Wolfe, Scott W

    2015-03-01

    Spontaneous nerve torsion is a rare cause of nerve palsy. We describe a case of nerve torsion affecting the radial nerve in order to inform radiologists of the existence of this condition and subtle features on cross-sectional imaging that can suggest the diagnosis preoperatively.

  5. Torsional Strengthening of RC Beams Using GFRP Composites

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

    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.

  6. 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.

  7. 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.

  8. Curvature and torsion in growing actin networks

    PubMed Central

    Shaevitz, Joshua W; Fletcher, Daniel A

    2011-01-01

    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. PMID:18560043

  9. [Cardiac herniation and torsion after transpericardial pneumonectomy].

    PubMed

    Schummer, W; Hottenrott, A; Nissel, C

    2016-07-05

    This article presents the case of a 43 year old woman with right-sided lung cancer. She underwent transpericardial pneumonectomy. After an uneventfull surgery, the patient was transferred to the intensive care unit for postoperative monitoring. She was hemodynamically stable and had already been extubated in the OR.On postoperative chest X‑ray a mediastinal shift to the operated side as well as a herniation of the heart into the right chest cavity was detected. While the patient remained hemodynamically stable a computed tomography of the chest was performed which confirmed the diagnosis of cardiac herniation and torsion. The lady underwent rethoracotomy the following day where the heart was repositioned and the pericardial defect was closed. She made an uneventfull recovery.Five years after the pneumonectomy she remains well and is without relapse of lung cancer.Mechanism for cardiac herniation and torsion, the clinical presentation and the typical radiologic signs are discussed. However, the clue to early diagnosis is a high index of clinical suspicion.It is highlighted that a hemodynamically unstable patient under these circumstances demands urgent rethoracotomy.

  10. A Torsional Oscillator Study of Solid Hydrogen

    NASA Astrophysics Data System (ADS)

    Clark, Anthony

    2005-03-01

    Since the observation of superflow in solid ^4He, we have become interested in duplicating this phenomenon in other systems. In Kim and Chan's original work, trace amounts of ^3He, on the order of parts per million, were added to the system and found to significantly affect the transition. However, there is an altogether different system that is perhaps less complicated, and may also exhibit superflow. On the basis of the de Boer parameter, the most quantum solid other than the helium isotopes, is that of hydrogen. Thus, we have begun a torsional oscillator study of solid H2 from dilution temperatures up to the triple point. Solid samples are formed by first filling the torsion bob with liquid H2 at ˜14K, where the H2 has already passed through ortho-para conversion chambers at 50K and 20K. The cell is then gradually cooled to the base temperature of our ^3He-^4He dilution refrigerator. We present our preliminary data of the resonant oscillation period as a function of temperature.

  11. 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.

  12. Two design strategies for enhancement of multilayer–DNA-origami folding: underwinding for specific intercalator rescue and staple-break positioning

    PubMed Central

    Ke, Yonggang; Bellot, Gaëtan; Voigt, Niels V.; Fradkov, Elena; Shih, William M.

    2012-01-01

    Single-layer DNA origami is an efficient method for programmable self-assembly of nanostructures approximating almost any desired two-dimensional shape from ~5 MDa of DNA building material. In this method, a 7 kilobase single “scaffold” strand is assembled with hundreds of oligodeoxyribonucleotide “staple” strands to form a parallel array of double helices. Multiple layers of such DNA sheets also can be designed to assemble into a stack, enabling construction of solid three-dimensional shapes with considerably greater mechanical rigidity than two-dimensional shapes; however, the folding yield often is much lower and the required folding times are much longer. Here we introduce two strategies for designing multi-layer DNA origami that demonstrate potential for boosting assembly yield: (1) individual base pairs can be inserted between crossovers, allowing for greater bowing of helices at positions away from crossovers and therefore reduced electrostatic repulsion. At the same time, this underwinding of double helices increases a destabilizing torsional strain energy but then also increases affinity for intercalators, and binding of such intercalators can relieve this stress. We also have exploited this enhanced affinity for intercalators to PEGylate the surface of the nanostructures in a noncovalent fashion using PEG-tris-acridine. (2) Positioning of staple-strand breaks in the DNA origami such that each staple strand includes a 14 nucleotide (nt) continuous segment that binds to a complementary 14 nt continuous segment of the scaffold can greatly improve folding yields. PMID:24653832

  13. Can Torsion BE Treated as Just another Tensor Field?

    NASA Astrophysics Data System (ADS)

    Nester, James M.; Wang, Chih-Hung

    Many alternative gravity theories use an independent connection which leads to torsion in addition to curvature. Some have argued that there is no physical need to use such connections, that one can always use the Levi-Civita connection and just treat torsion as another tensor field. We explore this issue here in the context of the Poincaré Gauge theory of gravity, which is usually formulated in terms of an affine connection for a Riemann-Cartan geometry (torsion and curvature). We compare the equations obtained by taking as the independent dynamical variables: (i) the orthonormal coframe and the connection and (ii) the orthonormal coframe and the torsion (contortion), and we also consider the coupling to a source. From this analysis we conclude that, at least for this class of theories, torsion should not be considered as just another tensor field.

  14. 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.

  15. Peculiar torsion dynamical response of spider dragline silk

    NASA Astrophysics Data System (ADS)

    Liu, Dabiao; Yu, Longteng; He, Yuming; Peng, Kai; Liu, Jie; Guan, Juan; Dunstan, D. J.

    2017-07-01

    The torsional properties of spider dragline silks from Nephila edulis and Nephila pilipes spiders are investigated by using a torsion pendulum technique. A permanent torsional deformation is observed after even small torsional strain. This behaviour is quite different from that of the other materials tested here, i.e., carbon fiber, thin metallic wires, Kevlar fiber, and human hair. The spider dragline thus displays a strong energy dissipation upon the initial excitation (around 75% for small strains and more for a larger strain), which correspondingly reduces the amplitude of subsequent oscillations around the new equilibrium position. The variation of torsional stiffness in relaxation dynamics of spider draglines for different excitations is also determined. The experimental result is interpreted in the light of the hierarchical structure of dragline silk.

  16. Methyl and skeletal torsion interaction in methyl thiolfluoroformate

    NASA Astrophysics Data System (ADS)

    Caminati, Walther; Meyer, Rolf

    1981-12-01

    The microwave spectrum of methyl thiolfluoroformate (FCOSCH 3) is reported for the ground state and seven vibrational satellites. The methyl group is in the syn conformation to the carbonyl group. The dipole moment components are μa = 2.89(2) D, μb = 0.30(8) D, and μc = 0. Spacings of A and E levels due to methyl internal rotation are analyzed for the ground state, the first excited methyl torsional state, and the first excited skeletal torsional state. An anomalous sequence of A and E levels occurring in the latter satellite arises from torsional interaction, according to two-dimensional model calculations. Potential parameters consistent with the three observed level separations are V3 = 304(5) cm -1, V6 = 23(1) cm -1 for the methyl torsion and either k = 1.912 or k = 2.936 cm -1 deg -2 for the skeletal torsional force constant.

  17. Amitriptyline effectively relieves neuropathic pain following treatment of breast cancer.

    PubMed

    Kalso, E; Tasmuth, T; Neuvonen, P J

    1996-02-01

    The effectiveness of amitriptyline in relieving neuropathic pain following treatment of breast cancer was studied in 15 patients in a randomised, double-blind placebo-controlled crossover study. The dose was escalated from 25 mg to 100 mg per day in 4 weeks. The placebo and amitriptyline phases were separated by a 2-week wash-out period. Visual analogue and verbal rating scales were used for the assessment of pain intensity and pain relief. Other measures included the number of daily activities disturbed by the pain, the Finnish McGill Pain Questionnaire, adverse effects, anxiety, depression, pressure threshold and grip strength. Amitriptyline significantly relieved neuropathic pain both in the arm and around the breast scar. Eight out of 15 patients had a more than 50% decrease in the pain intensity ('good responders') with a median dose of 50 mg of amitriptyline. The 7 patients who had a less than 50% effect had drug concentrations equaling those of the good responders. The 'poor responders' reported significantly more adverse effects with amitriptyline and placebo than the good responders. It is concluded that amitriptyline effectively reduced neuropathic pain following treatment of breast cancer. However, the adverse effects of amitriptyline put most of the patients off from using the drug regularly.

  18. 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

  19. Unusual DNA structures

    SciTech Connect

    Wells, R.D.; Harvey, S.C.

    1988-01-01

    The contents of this book are: Unusual DNS Structures and the Probes Used for Their Detection; The Specificity of Single Strand Specific Endonucleases; Chromatin STructure and DNA Structure at the hsp 26 Locus of Drosophilia; Cruciform Extrusion in Supercoiled DNA-Mechanisms and Contextual Influence; Torsional Stress, Unusual DNA Structures, and Eukaryotic Gene Expression; DNA Sequence and Structure: Bending to Biology. Cruciform Transitions Assayed Using a Psoralen Cross-linking Method: Applications to Measurements of DNA Torisonal Tension; NMR-Distance Geometry Studies of Helical Errors and Sequence Dependent Conformations of DNA in Solution; Hyperreactivity of the B-Z Junctions Probed by Two Aromatic Chemical Carcinogens; Inherently Curved DNA and Its Structural Elements; and DNA Flexibility Under Control: The Juma Algorithm and its Application to BZ Junctions.

  20. Microstructure and Microtexture Evolution of Pure Titanium during Single Direction Torsion and Alternating Cyclic Torsion

    NASA Astrophysics Data System (ADS)

    Chen, Han; Li, Fuguo; Liu, Jie; Li, Jinghui; Ma, Xinkai; Wan, Qiong

    2017-05-01

    Systematic experimental studies of microstructure and crystallographic texture of pure titanium during the Single Direction Torsion (SDT) and Alternating Cyclic Torsion (ACT) are carried out at room temperature. The microstructure evolution indicates that the grain size can be refined during SDT, while the grain morphology can be controlled during ACT. Also, lots of {10-12} and few {11-22} twins are observed and their area percentages increase with increasing torsion angles during SDT. The microtexture evolution states that the deformation texture first approaches to the B fiber (0, 90, 0 to 60 deg), and then stays away from B fiber (0, 90, 0 to 60 deg) with increasing plastic strain during SDT. The change of deformation texture is mainly attributed to the appearance of {10-12} twin. However, the deformation texture is always close to B fiber (0, 90, 0 to 60 deg) during ACT. Finally, the effects of different dislocation movements caused by SDT and ACT are discussed. Quantities of subgrains with high density dislocation are observed during SDT while the {10-12} and {11-22} twins intersect with each other, and high density dislocations distribute the twin during ACT.

  1. Microstructure and Microtexture Evolution of Pure Titanium during Single Direction Torsion and Alternating Cyclic Torsion

    NASA Astrophysics Data System (ADS)

    Chen, Han; Li, Fuguo; Liu, Jie; Li, Jinghui; Ma, Xinkai; Wan, Qiong

    2017-03-01

    Systematic experimental studies of microstructure and crystallographic texture of pure titanium during the Single Direction Torsion (SDT) and Alternating Cyclic Torsion (ACT) are carried out at room temperature. The microstructure evolution indicates that the grain size can be refined during SDT, while the grain morphology can be controlled during ACT. Also, lots of {10-12} and few {11-22} twins are observed and their area percentages increase with increasing torsion angles during SDT. The microtexture evolution states that the deformation texture first approaches to the B fiber (0, 90, 0 to 60 deg), and then stays away from B fiber (0, 90, 0 to 60 deg) with increasing plastic strain during SDT. The change of deformation texture is mainly attributed to the appearance of {10-12} twin. However, the deformation texture is always close to B fiber (0, 90, 0 to 60 deg) during ACT. Finally, the effects of different dislocation movements caused by SDT and ACT are discussed. Quantities of subgrains with high density dislocation are observed during SDT while the {10-12} and {11-22} twins intersect with each other, and high density dislocations distribute the twin during ACT.

  2. Torsional thrust stand for characterization of microthrusters

    NASA Astrophysics Data System (ADS)

    Cheah, K. H.; Low, K. S.

    2016-10-01

    This paper describes the setup of a precise thrust stand based on torsional pendulum design for characterizing the performance of microthrusters. Calibration has been carried out by using an improved version of electrostatic calibrator, which produces a wide range of accurate and repeatable calibration force. After the calibration, the thrust stand can resolve constant force from 40μN to 3.4mN and impulse bit from 7μNs to 340μNs. The usefulness of the thrust stand has been demonstrated by measuring the performance of two different microthrusters: a pulsed plasma thruster that produces impulse bit of 23.15μNs and a vaporizing liquid microthruster that produces steady state thrust of 633.5μN.

  3. 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.

  4. 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)

  5. 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.

  6. 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.

  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. Pain-relieving effect of local steroid injection in uvulopalatopharyngoplasty.

    PubMed

    Hirunwiwatkul, P

    2001-06-01

    An analytical prospective study was performed to determine the post-operative pain-relieving effect of local steroid suspension injection in uvulopalatopharyngoplasty. From February 2000 to October 2000, 48 adult patients from 20 to 67 years of age, were scheduled to receive uvulopalatopharyngoplasty. Triamcinolone acetonide (Kenacort A) was injected onto the raw surface of the left-sided tonsillar fossa and left-sided soft palate after tonsillectomy and uvulopalatopharyngoplasty. Other preoperative and post-operative medications including antibiotics, anesthesia and surgical techniques were standardized. Visual analog scales were used to assess the level of pain sensation on the left and right side of the throat daily from day 0 (Operative day) to post-operative day 10. A paired t-test showed significant differences in post-operative pain level between the study side (left) and the control side (right) at day 2, day 4, and in the overall analysis (p < 0.05).

  9. 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.

  10. Humeral torsion and passive shoulder range in elite volleyball players.

    PubMed

    Schwab, Laura M; Blanch, Peter

    2009-05-01

    To evaluate variations in humeral torsion in elite male volleyball players and determine whether these changes are related to training history, retrospective injury history and volleyball performance. Cross sectional design. Twenty-four elite male volleyball players. Humeral torsion, passive gleno-humeral rotation ranges and the available internal and external rotation from the humeral torsion neutral position of the dominant and non-dominant arm were measured. Training history and retrospective injury status were ascertained from a questionnaire. Performance was assessed by coach perceived spiking ability and peak serve velocity measures. Humeral torsion angles demonstrated the dominant arm to be on average 9.6 degrees more retroverted than the non-dominant arm (p=0.00). In the comparison of volleyball players with and without a history of overuse upper limb injury the most significant finding is on the non-dominant side, those with a history of injury had significantly decreased available external rotation from the humeral torsion neutral position (mean difference=-15.1, p=0.04). There was an unexpected negative weak relationship between age commenced and decreased humeral retroversion (r=-0.413, p=0.045). There did not appear to be any relationship between humeral torsion and performance measures. The dominant arm of elite male volleyball athletes is more retroverted. There was a tendency for stronger findings in the non-dominant arm in volleyball players with retrospective injury history. We were unable to find any significant correlation between humeral torsion angle and performance measures.

  11. 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.

  12. Reperfusion injury following testicular torsion and detorsion in prepubertal rats.

    PubMed

    Blank, M L; O'Neill, P J; Steigman, C K; Cobb, L M; Wilde, R A; Havenstein, P J; Chaudry, I H

    1993-01-01

    Acute testicular torsion is a surgical emergency which requires immediate intervention. Although damage to the gonad has been well documented, it remains unknown whether the majority of injury occurs during the period of torsion (ischemia) or following detorsion (reperfusion). The aims of this study were to determine: (1) whether damage following testicular torsion-detorsion has a reperfusion component similar to that described in other tissues, and (2) whether iron-catalyzed oxygen radical formation or altered calcium homeostasis plays a role in this injury. To study this, anesthetized prepubertal rats underwent 720 degrees intravaginal testicular torsion and were divided into groups of torsion only (ischemia) and torsion with reperfusion (ischemia/reperfusion). Reperfusion groups were treated prior to detorsion with either deferoxamine (iron chelator), diltiazem (calcium channel blocker), or saline vehicle. The results indicated that detorsion produces a qualitatively distinct reperfusion injury from that of non-reperfused testicles; however, such damage was not ameliorated by deferoxamine or diltiazem. Thus, testicular torsion-detorsion appears to have a significant reperfusion component that appears to not be mediated by iron-catalyzed oxygen radical formation or calcium injury.

  13. Management of suspected antenatal torsion: what is the best strategy?

    PubMed

    Stone, K T; Kass, E J; Cacciarelli, A A; Gibson, D P

    1995-03-01

    Currently, management of the newborn with suspected antenatal torsion is somewhat controversial. Many surgeons recommend early surgical exploration within the first few days of life, primarily to avoid errors in diagnosis. However, since the surgical and general anesthetic risks at this age are increased, it might be preferable to defer an operation until risks to the patient are minimized. The optimal solution to this dilemma would be the ability to diagnose torsion and exclude other conditions noninvasively. We present a series of 12 patients 1 to 14 days old who presented with a scrotal mass secondary to suspected antenatal testis torsion. Color Doppler ultrasound in each case demonstrated abnormal testicular blood flow and architecture consistent with testis torsion. Eventual exploration of all 12 patients confirmed prenatal torsion. We conclude that scrotal ultrasound with color Doppler enhancement can accurately identify neonates with antenatal testis torsion and exclude other scrotal pathological conditions. If elected, surgery for torsion can then be deferred until the risks of anesthesia and surgery are improved.

  14. [Torsion and necrosis of epiploic appendices of the large bowel].

    PubMed

    Timofeev, M E; Fedorov, E D; Krechetova, A P; Shapoval'iants, S G

    2014-01-01

    The features of the clinical symptoms was studied, the possibility of laparoscopy in modern diagnosis and treatment of epiploic appendices torsion and necrosis of the large bowel was assessed in the article. It was done the retrospective analysis of the medical records of 87 patients with a diagnosis of epiploic appendices torsion and necrosis of the large bowel. The patients had laparoscopic operations in our hospital in the period from January 1995 to December 2012. The clinical picture, laboratory and instrumental datas in cases of epiploic appendices torsion and necrosis were scarce and nonspecific. An abdominal pain preferentially localized in the lower divisions was the main symptom (97.7%). The instrumental methods did not allow to diagnose the torsion and necrosis of epiploic appendices in the majority of cases and all these techniques were used for the differential diagnosis with other diseases. The assumption of the presence of appendices torsion and necrosis occured just in 34.5% of cases before the operation. Diagnosis of epiploic appendices torsion and necrosis present significant difficulties on prehospital and preoperative stages. The diagnostic laparoscopy is the method of choice in unclear situations and it allows to diagnose the torsion and necrosis of epiploic appendices in 96.6% of cases. Successful surgical treatment by using laparoscopic approach is possible in 90.8% of cases.

  15. Nonmedical prescription pain reliever and alcohol consumption among cannabis users.

    PubMed

    Novak, Scott P; Peiper, Nicholas C; Zarkin, Gary A

    2016-02-01

    This study examined poly-drug use involving the use of cannabis with nonmedical prescription pain reliever use (NMPR) and alcohol use. Computer-assisted survey data from the National Survey on Drug Use and Health were examined. The NSDUH is an annual, cross-sectional survey of non-institutionalized citizens in the United States (ages 12+). Replicate analyses were conducted using the 2013 and 2003 survey waves. Higher levels of cannabis use were consistently associated with more frequent consumption of prescription pain relievers, with findings replicating in both 2013 and 2003. While the prevalence of dual users declined from 2003 (2.5%) to 2013 (2.3%), the average number of days used among dual users increased by an average of 20 days over that period. These changes largely occurred among those aged 35 or older, males, whites, and non-illicit drug users. Past-year marijuana use increased by 16% (10.8-12.6%, p-value<.001) whereas NMPR decreased by 15% (4.9-4.2%, p-value<.001). The largest changes occurred after 2011. Persons using the most cannabis generally had higher levels of alcohol use relative to those using the least amount of cannabis. There was a significant increase in the prevalence of dual use between 2003 (10.2%) and 2013 (11.6%), while the prevalence of past-year alcohol use remained relatively stable. Clinical efforts and public health interventions should consider the possible co-ingestion of cannabis with NMPR and alcohol, as concomitant use may portend negative health effects in the short and long-term. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  16. Nonmedical prescription pain reliever and alcohol consumption among cannabis users

    PubMed Central

    Novak, Scott P.; Peiper, Nicholas C.; Zarkin, Gary A.

    2016-01-01

    Background This study examined poly-drug use involving the use of cannabis with nonmedical prescription pain reliever use (NMPR) and alcohol use. Methods Computer-assisted survey data from the National Survey on Drug Use and Health were examined. The NSDUH is an annual, cross-sectional survey of non-institutionalized citizens in the United States (ages 12+). Replicate analyses were conducted using the 2013 and 2003 survey waves. Results Higher levels of cannabis use were consistently associated with more frequent consumption of prescription pain relievers, with findings replicating in both 2013 and 2003. While the prevalence of dual users declined from 2003 (2.5%) to 2013 (2.3%), the average number of days used among dual users increased by an average of 20 days over that period. These changes largely occurred among those aged 35 or older, males, whites, and non-illicit drug users. Past-year marijuana use increased by 16% (10.8–12.6%, p-value < .001) whereas NMPR decreased by 15% (4.9–4.2%, p-value < .001). The largest changes occurred after 2011. Persons using the most cannabis generally had higher levels of alcohol use relative to those using the least amount of cannabis. There was a significant increase in the prevalence of dual use between 2003 (10.2%) and 2013 (11.6%), while the prevalence of past-year alcohol use remained relatively stable. Conclusions Clinical efforts and public health interventions should consider the possible co-ingestion of cannabis with NMPR and alcohol, as concomitant use may portend negative health effects in the short and long-term. PMID:26748409

  17. Clinical measurement of compensatory torsional eye movement during head tilt.

    PubMed

    Lim, Han Woong; Kim, Ji Hong; Park, Seung Hun; Oh, Sei Yeul

    2017-03-01

    To measure the degree of compensatory torsional eye movement during head tilt using a fundus photography method. We enrolled 55 healthy subjects who were 20-66 years of age. Fundus photographs were obtained in the presumed baseline position and in stepwise head tilt positions to evaluate ocular torsion using a non-mydriatic fundus camera. Horizontal marks on the nose were photographed simultaneously to evaluate head tilt. Images were analysed using Photoshop to measure the degree of ocular torsion and head tilt. A consistent compensatory torsional eye movement was observed in all subjects during head tilt. The degree of compensatory torsional eye movement showed a positive correlation with the angle of head tilt. Ocular torsional disconjugacy was observed during head tilt, with larger excycloductional eye movement than incycloductional eye movement (4.88 ± 2.91° versus 4.50 ± 2.76°, p < 0.001). In multiple linear regression analysis, the degree of compensatory torsional eye movement was significantly associated with the degree of head tilt (β = 0.191, p < 0.001), and the direction of cycloduction (β = -0.548, p < 0.001). The fundus photography method is a non-invasive, accurate and objective tool for measuring compensatory torsional eye movement. Considering the availability of fundus photography in clinical ophthalmology practice, the proposed method can be used as a clinical tool to measure compensatory torsional eye movement. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  18. 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.

  19. 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.

  20. Relationship between humeral torsion and injury in professional baseball pitchers.

    PubMed

    Polster, Joshua M; Bullen, Jennifer; Obuchowski, Nancy A; Bryan, Jason A; Soloff, Lonnie; Schickendantz, Mark S

    2013-09-01

    High levels of humeral torsion allow baseball pitchers to achieve maximum external rotation in the late cocking phase of pitching with lower twisting and shear forces on the long head of the biceps tendon and rotator cuff tendons. Humeral torsion is inversely related to the incidence and severity of shoulder injuries and other upper extremity injuries in professional baseball pitchers. Case-control study; Level of evidence, 3. A total of 25 professional pitchers from a single Major League Baseball organization were prospectively recruited into this study. Computed tomography (CT) was performed on dominant and nondominant humeri, and image data were processed with a 3-dimensional volume-rendering postprocessing program. The software program was then modified to model a simplified throwing motion and to measure potential internal impingement distances in a small subset of players. Players were followed for 2 years after CT, and the number of days missed from pitching activities was recorded as a measure of injury severity and incidence. The mean dominant humeral torsion was 38.5° ± 8.9°; the mean nondominant humeral torsion was 27.6° ± 8.0°. The difference between dominant and nondominant torsions was significant (P < .0001). Among the 11 pitchers (44%) injured during follow-up, 5 players had shoulder injuries, 7 had elbow injuries, and 2 had finger injuries. Dominant humeral torsion was a statistically significant predictor of severe injuries (≥30 days; P = .048) but not of milder injuries. Among injured players, higher numbers of days missed because of injury were strongly correlated with lower degrees of dominant humeral torsion (r = -0.78; P = .005) and smaller differences between dominant and nondominant humeral torsions (r = -0.59; P = .055). There was no significant association between the incidence of shoulder injury and minimum glenoid-tuberosity distance in the dominant or nondominant shoulder or degree of dominant glenoid version. A strong

  1. Torsion of a wandering spleen: an unusual abdominal catastrophe.

    PubMed

    Riaz ul Haq, Muhammad; Elhassan, Elbagir; Mahdi, Diaa

    2014-11-01

    Wandering spleen is a rare clinical entity characterised by splenic hypermobility resulting from laxity or maldevelopment of the suspensory gastrosplenic, splenorenal, and phrenicocolic ligaments. Diagnosis is quite difficult, especially in children because of the lack of symptoms and signs until splenic torsion have occurred. An array of investigations is possible but US with color Doppler, CT with intravenous contrast and MRI are frequently being used to diagnose wandering spleen with or without torsion. We present a case of 5 years old child with torsion of wandering spleen to highlight the importance of prompt diagnosis and management.

  2. Acute torsion of wandering spleen: report of one case.

    PubMed

    Lien, Chi-Hone; Lee, Hung-Chang; Yeung, Chun-Yan; Chan, Wai-Tao; Wang, Nein-Lu

    2009-08-01

    Wandering spleen is a rare condition that can lead to splenic infarction or rupture if torsion persists. Early diagnosis and intervention are necessary, and abdominal ultrasonography and abdominal computed tomography are well accepted as the diagnostic imaging modalities. In this study, we present a boy with nic infarction due to acute torsion of a wandering spleen, after initial failure to demonstrate an ectopic spleen. Instead, acute torsion of the wandering spleen with spontaneous partial detorsion was incidentally found by multi-detector row CT with angiography. The patient was managed by splenectomy instead of splenopexy, because poor reperfusion after Laparoscopic detorsion.

  3. Torsional anharmonicity in the conformational thermodynamics of flexible molecules

    NASA Astrophysics Data System (ADS)

    Miller, Thomas F., III; Clary, David C.

    We present an algorithm for calculating the conformational thermodynamics of large, flexible molecules that combines ab initio electronic structure theory calculations with a torsional path integral Monte Carlo (TPIMC) simulation. The new algorithm overcomes the previous limitations of the TPIMC method by including the thermodynamic contributions of non-torsional vibrational modes and by affordably incorporating the ab initio calculation of conformer electronic energies, and it improves the conventional ab initio treatment of conformational thermodynamics by accounting for the anharmonicity of the torsional modes. Using previously published ab initio results and new TPIMC calculations, we apply the algorithm to the conformers of the adrenaline molecule.

  4. 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.

  5. 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. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Validation of an Automated Torsional and Warping Stress Analysis Program

    DTIC Science & Technology

    1992-08-19

    AD-A256 035 I HEI| I IIHAI l! VALIDATION OF AN AUTOMATED TORSIONAL AND WARPING STRESS ANALYSIS PROGRAM DI f ELECTE ND OCT 8 1992 A Special Research...7 2.2 Torsional Analysis Case Charts ....................... 8 2.3 Determination of Plane Bending, Torsional ............. 9 and Warping...Fixed-Free 6 W1Ox49 Fixed-Free 7 W6x15 Fixed-Free 8 W8x67 Fixed-Free 9 ClOx20 Fixed-Free 10 C12x30 Fixed-Free 11 C5x9 Fixed-Fire 12 MC18x42 Fixed-Free

  7. 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.

  8. Critical current degradation behaviour of GdBCO CC tapes in pure torsion and combined tension-torsion modes

    NASA Astrophysics Data System (ADS)

    Gorospe, Alking; Bautista, Zhierwinjay; Shin, Hyung-Seop

    2016-10-01

    Coated conductor (CC) tapes utilized in high-current-density superconducting cables are commonly subjected to different loading modes, primarily torsion and tension especially in the case of twisted stacked-tape cable. Torsion load can occur due to twisting along the length or when winding the CC tapes around a former, while tension load can occur due to pre-tension when coiled and as a hoop stress when the coil is energized. In this study, electromechanical properties of single CC tapes under torsion load were investigated using a new test apparatus. The results could provide basic information for cable designers to fully characterize stacked cables. Copper-electroplated and brass-laminated CC tapes fabricated with different deposition techniques were subjected to pure torsion and combined tension-torsion loading. The critical current, I c degradation behaviours of CC tapes under torsional deformation were examined. Also, the effect of further external lamination on the I c degradation behaviour of the CC tapes under such loading conditions was investigated. In the case of the combined tension-torsion test, short samples were subjected to twist pitches of 200 mm and 100 mm. Critical parameters including reversible axial stress and strain in such twist pitch conditions were also investigated.

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

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

    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.

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

    PubMed

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

    2016-06-15

    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.

  11. An Inexpensive Torsional Pendulum Apparatus for Rigidity Modulus Measurement.

    ERIC Educational Resources Information Center

    Tyagi, S.; Lord, A. E., Jr.

    1979-01-01

    Described is an easy to assemble, and inexpensive, torsional pendulum which gives an accuracy of measurement of the modulus of rigidity, G, comparable to the accuracy obtained with the more expensive commercially available student models. (Author/GA)

  12. 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.

  13. 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.

  14. Torsional Dynamics of Steerable Needles: Modeling and Fluoroscopic Guidance

    PubMed Central

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

    2017-01-01

    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 semi-transparent 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

  15. Effect of tensile and torsion on GMI in amorphous wire

    NASA Astrophysics Data System (ADS)

    Blanco, J. M.; Zhukov, A.; Gonzalez, J.

    1999-05-01

    GMI effect, Δ Z/Z = [ Z( H) - Z( Hmax)]/ Z( Hmax) has been measured in (Fe 0.94Co 0.06) 72.5B 15Si 12.5 wire under tensile, σ ten, and torsional, σ tor, stresses. Generally Δ Z/Z( H) dependence has a non-monotonic shape with a maximum at certain axial magnetic field, Hm. Both tension and torsion modify Δ Z/Z( H) dependence. Application of tension results in an increase of Hm with σ ten. Torsional stress dependence of GMI effect has asymmetry with a maximum at torsion angle, φ, around + 12π/m in as-cast wire, when Δ Z/Z is around 250%. An increase of Δ Z/Zm up to 350% and change of Δ Z/Z(φ) dependence towards a nearly symmetric shape have been observed after Joule heating.

  16. 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.

  17. Torsional Newton-Cartan geometry from Galilean gauge theory

    NASA Astrophysics Data System (ADS)

    Banerjee, Rabin; Mukherjee, Pradip

    2016-11-01

    Using the recently advanced Galilean gauge theory (GGT) we give a comprehensive construction of torsional Newton-Cartan (NC) geometry. The coupling of a Galilean symmetric model with background NC geometry following GGT is illustrated by a free nonrelativistic scalar field theory. The issue of spatial diffeomorphism (Son and Wingate 2006 Ann. Phys. 321 197-224 Banerjee et al 2015 Phys. Rev. D 91 084021) is focussed from a new angle. The expression of the torsionful connection is worked out, which is in complete parallel with the relativistic theory. Also, smooth transition of the connection to its well known torsionless expression is demonstrated. A complete (implicit) expression of the torsion tensor for the NC spacetime is provided where the first-order variables occur in a suggestive way. The well known result for the temporal part of torsion is reproduced from our expression.

  18. 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.

  19. New torsion potential expression for molecules without rotational symmetry

    NASA Astrophysics Data System (ADS)

    Ji, Xiaobo; Yan, Liuming; Lu, Wencong

    2008-06-01

    A new torsion potential function for bond rotations without rotational symmetry is proposed. This function is composed of a few Gaussian-type terms each corresponding to an eclipsed conformation of the 1,2 substituents of the C-C bonds. Different from the truncated Fourier series or the truncated cosine polynomial, it is easy to determine how many terms are needed to represent any type of torsion potential barrier at a glance using the Gaussian-type function. It could also intuitively deduce the physical meaning of the expansion parameters of the new torsion potential function, which corresponds to the barrier height, the dihedral defining the eclipsed conformations, and the size of the substituents, respectively. The new torsion potential function is also applied to the 1, 2-substituted haloethanes with satisfactory results, where three Gaussian-type terms corresponding to the fully eclipsed and the partially eclipsed conformations are needed.

  20. [Fertility after experimental torsion of the spermatic cord (author's transl)].

    PubMed

    Ludwig, G; Haselberger, J; Kagelmacher, B

    1980-01-01

    In groups of 10 specimens the testicles of 100 Wistar rats were half unilaterally half bilaterally rotated 720 degrees and retorted 1, 2, 4, 6 and 8 hours after torsion. The fertility rate was investigated by copulation experiments following experimental torsion of the spermatic cord. Fertility was demonstrated by pregancy. Independently of torsion period the fertility rate of unilateral contorted specinens was 60% -- like in both control groups. The bilaterally contorted animals were fertile in 40% from the 1 h -- group and in 30% from the 2 hours -- group. If the torsion period was longer than 2 hrs. bilaterally conterted animals were infertile in all cases. There is no influence of unilateral conterted testicle on contralateral uncontorted testicle.

  1. 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.

  2. 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.

  3. Muscular Basis of Whisker Torsion in Mice and Rats.

    PubMed

    Haidarliu, Sebastian; Bagdasarian, Knarik; Shinde, Namrata; Ahissar, Ehud

    2017-09-01

    Whisking mammals move their whiskers in the rostrocaudal and dorsoventral directions with simultaneous rolling about their long axes (torsion). Whereas muscular control of the first two types of whisker movement was already established, the anatomic muscular substrate of the whisker torsion remains unclear. Specifically, it was not clear whether torsion is induced by asymmetrical operation of known muscles or by other largely unknown muscles. Here, we report that mystacial pads of newborn and adult rats and mice contain oblique intrinsic muscles (OMs) that connect diagonally adjacent vibrissa follicles. Each of the OMs is supplied by a cluster of motor end plates. In rows A and B, OMs connect the ventral part of the rostral follicle with the dorsal part of the caudal follicle. In rows C-E, in contrast, OMs connect the dorsal part of the rostral follicle to the ventral part of the caudal follicle. This inverse architecture is consistent with previous behavioral observations [Knutsen et al.: Neuron 59 (2008) 35-42]. In newborn mice, torsion occurred in irregular single twitches. In adult anesthetized rats, microelectrode mediated electrical stimulation of an individual OM that is coupled with two adjacent whiskers was sufficient to induce a unidirectional torsion of both whiskers. Torsional movement was associated with protracting movement, indicating that in the vibrissal system, like in the ocular system, torsional movement is mechanically coupled to horizontal and vertical movements. This study shows that torsional whisker rotation is mediated by specific OMs whose morphology and attachment sites determine rotation direction and mechanical coupling, and motor innervation determines rotation dynamics. Anat Rec, 300:1643-1653, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  4. Salvage splenopexy for torsion of wandering spleen in a child.

    PubMed

    Goyal, Ram Babu; Gupta, Rahul; Prabhakar, Girish; Mathur, Praveen; Mala, Tariq Ahmed

    2014-01-01

    The wandering spleen is a rare condition characterized by the absence or underdevelopment of one or all of the splenic suspensory ligaments that resulting in increased splenic mobility and rarely torsion. Preventing infarction is the aim of a prompt surgery by splenopexy. We report a case of salvage splenopexy in torsion of a wandering spleen in a three year old girl presented with severe abdominal pain for three days.

  5. Salvage Splenopexy for Torsion of Wandering Spleen in a Child

    PubMed Central

    Goyal, Ram Babu; Prabhakar, Girish; Mathur, Praveen; Mala, Tariq Ahmed

    2014-01-01

    The wandering spleen is a rare condition characterized by the absence or underdevelopment of one or all of the splenic suspensory ligaments that resulting in increased splenic mobility and rarely torsion. Preventing infarction is the aim of a prompt surgery by splenopexy. We report a case of salvage splenopexy in torsion of a wandering spleen in a three year old girl presented with severe abdominal pain for three days. PMID:24834385

  6. 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.

  7. 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

  8. Thermal conductivity and torsional oscillations of solid 4He

    NASA Astrophysics Data System (ADS)

    Brazhnikov, M. Yu.; Zmeev, D. E.; Golov, A. I.

    2012-11-01

    Polycrystalline samples of hcp 4He of molar volume Vm = 19.5 cm3 with small amount of 3He impurities were grown in an annular container by the blocked-capillary method. Three concentrations of 3He, x3, were studied: isotopically purified 4He with the estimated x3 < 10-10, commercial `well-grade' helium with x3 ˜ 3.10-7 and a mixture with x3 = 2.5.10-6. Torsional oscillations at two frequencies, 132.5 and 853.6 Hz, and thermal conductivity were investigated before and after annealing. The solid helium under investigation was located not only in the annular container but also in the axial fill line inside two torsion rods and dummy bob of the double-frequency torsional oscillator. The analysis of the frequency shifts upon loading with helium and changing temperatures of different parts of the oscillator suggests that the three techniques probe the properties of solid helium in three different locations: the two different torsion modes respond to the changes of the shear modulus of solid helium in either of the two torsion rods while the thermal conductivity probes the phonon mean free path in solid helium inside the annular container. The temperature and width of the torsional anomaly increase with increasing frequency and x3. The phonon mean free path increases with increasing x3. Annealing typically resulted in an increased phonon mean free path but often in little change in the torsional oscillator response. While the magnitude of the torsional anomaly and phonon mean free path can be very different in different samples, no correlation was found between them.

  9. Association between Nonmedical Marijuana and Pain Reliever Uses among Individuals Aged 50.

    PubMed

    Choi, Namkee G; DiNitto, Diana M; Marti, C Nathan; Choi, Bryan Y

    2017-07-12

    Marijuana and pain reliever use for medical and nonmedical purposes has been increasing among older adults. Using the 2012-2013 U.S. National Survey on Alcohol and Related Conditions (NESARC-III), this study examined: (1) the association between past-year nonmedical marijuana and pain reliever use among adults aged 50+ years (N = 14,715); and (2) sociodemographic, health, and pain-related correlates of nonmedical marijuana and/or pain reliever use. The findings show that 3.87% and 3.12%, respectively, used marijuana and pain relievers nonmedically and 14.40% of marijuana users, compared to 2.67% of nonusers, used pain relievers nonmedically. Controlling for sociodemographics, health status, pain interference, and mental and other substance use disorders, marijuana use anduse disorder were significantly associated with nonmedical pain reliever use and opioid use disorder, respectively. Compared to marijuana users (with or without nonmedical use of pain relievers), nonmedical pain reliever users (without marijuana) are older, married, and women. Users of both substances nonmedically are a small group (0.56% of the 50+ age group), but they are at greatest risk of lifetime opioid, alcohol, and nicotine use disorders. Pain interference is a significant correlate of nonmedical pain reliever use. Healthcare providers should assess for the nonmedical use of these medicines/drugs and help older adults receive effective pain treatment.

  10. 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

  11. Testicular torsion, oxidative stress and the role of antioxidant therapy.

    PubMed

    Dokmeci, Dikmen

    2006-01-01

    Testicular torsion is a urological syndrome caused mainly by a twist in the spermatic cord. It constitutes a surgical emergency and affects newborns, children and adolescent boys. The torsion must be treated promptly to avoid loss of function of ipsilateral and contralateral testis. This syndrome often leads to infertility of the ipsilateral (torted) and contralateral (not torted) testis,but the mechanisms of cellular injury remain still incompletely understood. The primary pathophysiologic event in testicular torsion is ischemia followed by reperfusion; thus, testicular torsion/detorsion is an ischemia/reperfusion (I/R) injury to the testis. Testicular torsion and detorsion causes morphological and biochemical changes by both ischemia and reperfusion of the tissues. These I/R injury is associated with overgeneration of reactive oxygen species (ROS) and reactive nitrogen species (RNS), and also with a common mechanism to other organs such as brain, heart and kidneys. Although the results are not conclusive and the molecular mechanism by which antioxidants control male fertility have not yet been clearly identified, several antioxidant enzymes and antioxidant drugs have been studied to prevent such I/R injury in testis. As a result, antioxidant therapy may represent a new non-hormonal option within a broader therapeutic strategy in men with ROS-mediated infertility such as testicular torsion.

  12. 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.

  13. Torsion of the left ventricle during pacing with MRI tagging

    NASA Astrophysics Data System (ADS)

    Sorger, Jonathan M.; Wyman, Bradley T.; Faris, Owen P.; Hunter, William R.; McVeigh, Elliot R.

    2000-04-01

    In this study the effects of different pacing protocols on left ventricular (LV) torsion was evaluated over the full cardiac cycle. A systolic and diastolic series of Magnetic Resonance Imaging scans were combined and used to calculate the torsion of the LV. The asynchronous contraction resulting from ventricular pacing interferes with the temporal evolution of LV torsion. From these experiments we have shown that measuring torsion is an extremely sensitive indicator of the existence of ectopic excitation. The torsion of the left ventricle was investigated under three different protocols: (1) Right atrial pacing, (2) Right ventricular pacing and (3) Simultaneous pacing from the right ventricular apex and left ventricular base. The temporal evolution of torsion was determined from tagged magnetic resonance images and was evaluated over the full cardiac cycle. The peak twist Tmax for the RA paced heart was 11.09 (+/- 3.54) degrees compared to 6.06 (+/- 1.65) degrees and 6.09 (+/- 0.68) degrees for the RV and Bi-V paced hearts respectively. While biventricular pacing has been shown to increase the synchrony of contraction, it does not preserve the normal physiological twist patterns of the heart.

  14. 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.

  15. Use of opioid pain relievers following extraction of third molars.

    PubMed

    Weiland, Breanna M; Wach, Anthony G; Kanar, Brent P; Castele, Matthew T; Sosovicka, Mark F; Cooke, Matthew R; Moore, Paul A

    2015-02-01

    Following extraction of third molars, it is common practice for oral and maxillofacial surgeons to provide a prescription for an opioid-containing analgesic such as hydrocodone with acetaminophen. Because the instructions for use most often indicate that these analgesics are to be taken "as needed for pain," it is unknown how many of the prescribed postoperative analgesic tablets are needed and actually taken. Therefore, an assessment of patient pain experiences and actual opioid analgesic usage was carried out using structured telephone interviews of patients performed 1 and 7 days following their thirdmolar extraction surgery. Forty-eight adolescents and young adults, ages 15 to 30 years, participated in this assessment. A review of the surgeon's notes indicated that the median number of prescribed opioid-containing analgesics (ie, Vicodin®, Norco®, Lorcet®, Percocet®) was 20 tablets (range 10 to 40). The median consumption during the first 24 hours was reported to be three tablets (range 0 to 10), and the total consumption for all 7 days was eight tablets (range 0 to 34). Four patients reported nausea or vomiting in the first 24 hours, and six patients reported nausea or vomiting during the following 6 days of recovery. The initial prescriptions provided adequate relief for 45 of the 48 patients. Higher consumption of opioid pain relievers (OPRs) was associated with a longer duration of surgery and the occurrence of postoperative infections.

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. Relieving Pain using Dose-Extending Placebos: A Scoping Review

    PubMed Central

    Colloca, Luana; Enck, Paul; DeGrazia, David

    2017-01-01

    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 22studies 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. Importantly, provided that nondisclosure is pre-authorized 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

  1. 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.

  2. Inheritance of idiopathic torsion dystonia among Jews.

    PubMed Central

    Zilber, N; Korczyn, A D; Kahana, E; Fried, K; Alter, M

    1984-01-01

    Idiopathic torsion dystonia (ITD) has long been considered to be genetically determined, but the pattern of inheritance has been unclear. It has been suggested that inheritance may differ in Jews and non-Jews. In the present study, data gathered in a nationwide survey of ITD in Israel were analysed. Between 1969 and 1980, 47 patients were collected, of whom 40 were of European origin. In these European Jews, the ITD frequency was about 1:23 000 live births, which was five-fold greater than in Jews of Afro-Asian origin. Assuming that all cases fit the same genetic model, an X linked or a simple autosomal recessive model of inheritance did not agree well with our data. An autosomal dominant model with low penetrance could have accounted for our observations and would yield an ITD gene frequency in European Jews of 3 to 4:100 000. In view of the increased ages of their fathers, the isolated cases may have included some new mutations. Multifactorial inheritance was also possible. However, it may be inappropriate to assume that all cases have the same genetic basis, or even that all are inherited. PMID:6694180

  3. Torsion-vibration coupling in S1 toluene: Implications for IVR, the torsional barrier height, and rotational constants.

    PubMed

    Gascooke, Jason R; Virgo, Edwina A; Lawrance, Warren D

    2015-07-28

    We have examined the S1←S0 transition of toluene in the region from the 0(0)(0) band to ∼210 cm(-1) above it. The spectrum reveals methyl rotor levels of 0(0) toluene up to m = 6 and of the lowest frequency vibration, 20(1), up to m = 4. The rotor levels of both 20(1) and 0(0) are perturbed by torsion-vibration coupling. The inclusion of torsion-vibration coupling leads to the S1 torsional barrier, V6, being revised from -26.376 cm(-1) to -5.59 cm(-1). The torsion-vibration coupling constant is determined to be 21.1 cm(-1). This situation is the S1 analogue of that recently reported for S0 toluene [Gascooke et al., J. Chem. Phys. 142, 024315 (2015)]. Torsion-vibration coupling alters both the rotor band positions and the rotational contours, which particularly affects the rotational constants associated with motion around the a-axis, about which the methyl group rotates. Every vibrational state (indicated generically by X) will be involved in the corresponding X - X20(1) torsion-vibration coupling; so, this interaction permeates the vib-rotor manifold, providing a mechanism to enhance intramolecular vibrational energy redistribution.

  4. Psychological stress-relieving effects of chewing - Relationship between masticatory function-related factors and stress-relieving effects.

    PubMed

    Tasaka, Akinori; Kikuchi, Manaki; Nakanishi, Kousuke; Ueda, Takayuki; Yamashita, Shuichiro; Sakurai, Kaoru

    2017-07-01

    The objective of the present study was to investigate the relationship between masticatory function-related factors (masticatory performance, occlusal contact area, maximum bite force, number of chewing strokes, and muscle activity) and the stress-relieving effects of chewing. A total of 28 healthy male subjects were instructed to rest or chew for 10min after 30min of stress loading with arithmetic calculations. Their stress state was assessed by measuring salivary cortisol levels. Saliva was collected at three time points: before stress loading, immediately after stress loading, and 10min after stress loading. Compared to resting, chewing produced a significantly greater reduction in the rate of change in salivary cortisol levels 10min after stress loading. A negative correlation was observed between the rate of decrease in salivary cortisol levels and the number of chewing strokes. No significant correlation was observed between the rate of decrease in salivary cortisol levels and other measurement items. In healthy dentulous people, the number of chewing strokes has been shown to be a masticatory function-related factor that affects stress relief from chewing, suggesting the possibility that more appropriate chewing would produce a greater effect psychological stress relief. Copyright © 2017 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  5. Scrotal Exploration for Testicular Torsion and Testicular Appendage Torsion: Emergency and Reality

    PubMed Central

    Yu, You; Zhang, Feng; An, Qun; Wang, Long; Li, Chao; Xu, Zhilin

    2015-01-01

    Background: Scrotal exploration is considered the procedure of choice for acute scrotum. Objectives: We evaluated the importance of early diagnosis and testicular salvage on the therapeutic outcomes of patients with pediatric testicular torsion (TT) and testicular appendage torsion (TAT) in our geographic area. Patients and Methods: We performed a retrospective database analysis of patients who underwent emergency surgery for TT or TAT between January 1996 and June 2009. Patient history, physical examination findings, laboratory test results, color Doppler sonography (CDS) results, and surgical findings were reviewed. Results: A total of 65 cases were included in our analysis. Forty-two cases were followed up for at least 3 months. Testicular tenderness was identified as the major clinical manifestation of TT, while only a few patients with TAT presented with swelling. CDS was an important diagnostic modality. The orchiectomy rate was 71% in the TT group. Conclusions: Cases of acute scrotum require attention in our area. Early diagnosis and scrotal exploration could salvage the testis or preserve normal function without the need for surgery. PMID:26199690

  6. 49 CFR 192.201 - Required capacity of pressure relieving and limiting stations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Required capacity of pressure relieving and... Design of Pipeline Components § 192.201 Required capacity of pressure relieving and limiting stations. (a... protect a pipeline must have enough capacity, and must be set to operate, to insure the following: (1) In...

  7. Self-administered pain-relieving manoeuvres in primary headaches.

    PubMed

    Zanchin, G; Maggioni, F; Granella, F; Rossi, P; Falco, L; Manzoni, G C

    2001-09-01

    We investigated the use of self-administered pain-relieving manoeuvres on a sample of 400 patients with primary headaches--represented by an even distribution of migraine without aura (MO), migraine with aura (MA), episodic tension-type headache (TH), and cluster headache (CH)--consecutively seen at Padua and Parma Headache Centres. Manoeuvres on various regions of the head were used by 258 patients (65% of the cases). The most applied procedures were: compression (114 out of 382 manoeuvres; 30%), application of cold (27%), massage (25%) and application of heat (8%). A significant (P < 0.001) relationship was found between headache diagnoses and type of manoeuvre. In MO patients the application of cold (38% of the manoeuvres) and compression (36%), used mainly on the forehead and temples, prevailed; compression, mainly on the temples, was the most frequent procedure (44%) in MA patients. Massage on the temples and nape was the predominant manoeuvre (43%) in TH patients, whereas in the CH group, which more often required heterogeneous procedures, none of the above-mentioned manoeuvres was prevalent. Compression, as a diagnostic criterion for MO, had a sensitivity of 33% and a specificity of 86%; for the application of cold the figures were 36% and 84%, respectively. Massage had a sensitivity of 33% and a specificity of 80% for TH. The efficacy of the self-administered manoeuvres in reducing pain was scarce. Only 8% of the manoeuvres, in fact, resulted in a good or excellent pain control. Moreover, the efficacy of the manoeuvre was often momentary, wearing off when the manoeuvre stopped. In spite of this, 46% of the subjects used the manoeuvres constantly, at each attack.

  8. Efficacy of Carbon Microcoils in Relieving Cervicogenic Dizziness

    PubMed Central

    Bittar, Roseli; Alves, Nédison Gomes Paim; Bertoldo, César; Brugnera, Cibele; Oiticica, Jeanne

    2016-01-01

    Introduction Cervical pain contributes to postural deviations and imbalance. Nanotechnology may be used for the treatment of neck pain by fixing to the skin small rounds silicone patches containing double spiral carbon nanotubes arranged in the form of a coil (Helical), which would then relieve dizziness caused by muscular contraction. Objective The objective of this study is to Evaluate pain and dizziness scores before and after Helical patches effect on cervicogenic dizziness treatment. Methods The selected patients should have neck pain arising from muscle contraction with loss of balance or instability lasting more than 90 days and normal electrooculography. Treatment consisted of placing 10 Helical patches distributed as follows: two in the upper cervical area, two in the lower cervical area (near the 5th and 6th vertebrae), two in the upper trapezius muscle area (between neck and shoulder), and four in the tender point area (as reported by the patient). Using a Visual Analogue Scale (VAS), we matched pain and dizziness scores from Day 1 to those from Day 15 and Day 30 using Mann-Whitney test. Results There was a significant difference between pain score reported on Day 1 and Day 15 (Z = 2.43, U = 5, p = 0.01). We also found significant differences between dizziness scores reported on days 1 and 15 (Z = 2.62, U = 3.5, p = 0.01) and days 1 and 30 (Z = 2.36, U = 5.5, p = 0.01). Conclusion The Helical patches seem to be an effective treatment for cervicogenic dizziness. PMID:28050200

  9. Early onset torsion dystonia (Oppenheim's dystonia)

    PubMed Central

    Kamm, Christoph

    2006-01-01

    Early onset torsion dystonia (EOTD) is a rare movement disorder characterized by involuntary, repetitive, sustained muscle contractions or postures involving one or more sites of the body. A US study estimated the prevalence at approximately 1 in 30,000. The estimated prevalence in the general population of Europe seems to be lower, ranging from 1 in 330,000 to 1 in 200,000, although precise numbers are currently not available. The estimated prevalence in the Ashkenazi Jewish population is approximately five to ten times higher, due to a founder mutation. Symptoms of EOTD typically develop first in an arm or leg in middle to late childhood and progress in approximately 30% of patients to other body regions (generalized dystonia) within about five years. Distribution and severity of symptoms vary widely between affected individuals. The majority of cases from various ethnic groups are caused by an autosomal dominantly inherited deletion of 3 bp (GAG) in the DYT1 gene on chromosome 9q34. This gene encodes a protein named torsinA, which is presumed to act as a chaperone protein associated with the endoplasmic reticulum and the nuclear envelope. It may interact with the dopamine transporter and participate in intracellular trafficking, although its precise function within the cell remains to be determined. Molecular genetic diagnostic and genetic counseling is recommended for individuals with age of onset below 26 years, and may also be considered in those with onset after 26 years having a relative with typical early onset dystonia. Treatment options include botulinum toxin injections for focal symptoms, pharmacological therapy such as anticholinergics (most commonly trihexiphenydil) for generalized dystonia and surgical approaches such as deep brain stimulation of the internal globus pallidus or intrathecal baclofen application in severe cases. All patients have normal cognitive function, and despite a high rate of generalization of dystonia, 75% of those patients

  10. Isomerization of the RPSB chromophore in the gas phase along the torsional pathways using QTAIM

    NASA Astrophysics Data System (ADS)

    Ping, Yang; Xu, Tianlv; Momen, Roya; Azizi, Alireza; Kirk, Steven R.; Filatov, Michael; Jenkins, Samantha

    2017-10-01

    A QTAIM investigation of the torsion in both the clockwise and counter-clockwise directions about the π bonds of the retinal protonated Schiff base chromophore in the lowest electronically excited state provided a detailed description of the changing bonding topology that was sensitive to both the torsion and the direction of torsion. Analysis of the separate torsion calculations demonstrated a clear order of preferred bonding torsion in terms of principles of maximizing bonding. Unusual behavior of the bond ellipticity in the S1 state was found for the two less favorable bonds for torsion and explained in terms of the presence of weak bonding interactions.

  11. Antiapoptotic effects of dehydroepiandrosterone on testicular torsion/detorsion in rats.

    PubMed

    Yapanoglu, T; Aksoy, Y; Gursan, N; Ozbey, I; Ziypak, T; Calik, M

    2008-02-01

    In the present study, we aimed to evaluate the effects of dehydroepiandrosterone (DHEA) on apoptosis of testicular germ cells after repair of testicular torsion in rats. Twenty-four adult male Sprague-Dawley rats were randomly divided into four groups, with six rats in each group: sham operation, torsion/detorsion (T/D), T/D + vehicle, and T/D + DHEA. Three hours before detorsion, 50 mg kg(-1) DHEA was given intraperitoneally to T/D + DHEA group. In all groups, bilateral orchiectomies were performed and both testicles were histologically examined, with apoptosis detected using the in situ DNA fragmentation [terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL)] system, with morphological damage detected using a four-level grading scale in each specimen. The testes of the sham group showed a normal histology. In T/D and T/D + vehicle groups, apoptotic spermatogonia and spermatocyte number were significantly higher than in the sham group (P < 0.01 for all). The T/D + DHEA group showed a reduction in apoptotic spermatocyte and spermatogonia number in seminiferous epithelia compared with T/D group (P < 0.01 for both). Apoptotic cell number of contralateral testes did not reveal any significant differences among these groups (P > 0.05). Specimens from T/D and T/D + vehicle had a significantly greater histological injury than sham and T/D + DHEA groups in the ipsilateral testes (P < 0.01 for both). Therefore, the results suggest that DHEA may be a protective agent for preventing apoptosis caused by testicular torsion.

  12. 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.

  13. Malpractice Litigation and Testicular Torsion: A Legal Database Review.

    PubMed

    Colaco, Marc; Heavner, Matthew; Sunaryo, Peter; Terlecki, Ryan

    2015-12-01

    The litigious nature of the American medical environment is a major concern for physicians, with an estimated annual cost of $10 billion. The purpose of this study is to identify causes of litigation in cases of testicular torsion and what factors contribute to verdicts or settlements resulting in indemnity payments. Publicly available jury verdict reports were retrieved from the Westlaw legal database (Thomson Reuters, New York, NY). In order to identify pertinent cases, we used the search terms "medical malpractice" and "testicular torsion" with date ranging from 2000 to 2013. Jury verdicts, depositions, and narrative summaries were evaluated for their medical basis, alleged malpractice, findings, and indemnity payment(s) (if any). Fifty-two cases were identified that were relevant to this study. Fifty-one percent of relevant cases were found in favor of the defendant physician, with the remaining 49% involving an indemnity payment (13% of which were settled). The most commonly sued medical providers were emergency physicians (48% of defendants), with urologists being second most common and making up 23% of the defendant pool. Emergency physicians were significantly more likely to make indemnity payments than urologists. Testicular torsion is a delicate condition and requires expertise in evaluation and treatment. When emergency physicians choose not to consult an urologist for possible torsion, they leave themselves open to litigation risk. When an urologist is involved in torsion litigation, they are rarely unsuccessful in their defense. Finally, ultrasound is no guarantee for success against litigation. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Torsion as a dark matter candidate from the Higgs portal

    NASA Astrophysics Data System (ADS)

    Belyaev, Alexander S.; Thomas, Marc C.; Shapiro, Ilya L.

    2017-05-01

    Torsion is a metric-independent component of gravitation, which may provide a more general geometry than the one taking place within general relativity. On the other hand, torsion could lead to interesting phenomenology in both particle physics and cosmology. In the present work it is shown that a torsion field interacting with the SM Higgs doublet and having a negligible coupling to standard model (SM) fermions is protected from decaying by a Z2 symmetry, and therefore becomes a promising dark matter (DM) candidate. This model provides a good motivation for Higgs portal vector DM scenario. We evaluate the DM relic density and explore direct DM detection and collider constraints on this model to understand its consistency with experimental data and establish the most up-to-date limits on its parameter space. We have found in the model when the Higgs boson is only partly responsible for the generation of torsion mass, there is a region of parameter space where torsion contributes 100% to the DM budget of the Universe. Furthermore, we present the first results on the potential of the LHC to probe the parameter space of minimal scenario with Higgs portal vector DM using mono-jet searches and have found that LHC at high luminosity will be sensitive to the substantial part of model parameter space which cannot be probed by other experiments.

  15. [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.

  16. The intermountain power project commissioning - Subsynchronous torsional interaction tests

    SciTech Connect

    Wu, C.T.; Peterson, K.J. ); Pinko, R.J.; Kankam, M.D.; Baker, D.H. )

    1988-10-01

    Subsyncronous torsional vibration as a result of electrochemical interaction between the HVDC controls and a turbine-generator was first discovered during the commissioning of the Square Butte Project in 1977. The level of interaction between the HVDC controls and the turbine-generator depends on several interacting factors: the characteristic torsional frequencies of the turbine-generator, the bandwidth of the HVDC controls and the relative strength of the connecting ac system. For the Intermountain Power Project (IPP), early analysis of these interacting factors indicated that there exist definite potential for subsynchronous oscillation to occur. The calculated torsional frequencies of the IPP units showed that the first mode frequency is 14.0 Hz and is within the typical bandwidth of an HVDC control which is between 10-20 Hz. The HVDC controls, therefore, can influence the torsional stability of the IPP units. Further, the IPP turbine-generators are required to operate isolated on the HVDC rectifier terminal, with no other interconnecting ac network. This ''radial'' mode of operation will result in maximum interaction between the converter station and the IPP units. It became obvious that special measure must be implemented in the design of the IPP HVDC control system to modify its typical characteristics to avoid the occurrence of the subsynchronous oscillation. This paper presents the results of the subsynchronous torsional interaction (SSTI) tests that were performed during the commissioning of the IPP Unit 1 and the HVDC Transmission system.

  17. A torsion quasi-zero stiffness vibration isolator

    NASA Astrophysics Data System (ADS)

    Zhou, Jiaxi; Xu, Daolin; Bishop, Steven

    2015-03-01

    A torsion vibration isolator with quasi-zero stiffness (QZS) is proposed to attenuate the transmission of torsional vibration along a shaft system, which also plays a role of coupling between shafts. A pre-compressed cam-roller mechanism is designed to provide torsional negative stiffness that counteracts with the positive torsion stiffness of the vulcanized rubber between shafts. With the design parameters are set to satisfy a unique condition, the stiffness of the isolator delivers a QZS property about the equilibrium position. A nonlinear mathematical model is developed and its dynamic characteristics are further analyzed by using the Harmonic Balance method. A typical folded resonance curve occurs when the vibration amplitude is plotted as the excitation frequency is varied, illustrating a jump phenomenon in the response. The efficiency of vibration attenuation is estimated under a designed torque load, showing that the torsion QZS vibration isolator outperforms the corresponding linear counterpart, especial in low frequency ranges. Furthermore, the torque transmissibility of the QZS isolator is also studied to demonstrate the performance of the QZS isolator when the actual torque deviates from the design load.

  18. Optical fiber accelerometer based on MEMS torsional micromirror

    NASA Astrophysics Data System (ADS)

    Zeng, Fanlin; Zhong, Shaolong; Xu, Jing; Wu, Yaming

    2008-03-01

    A novel structure of optical fiber accelerometer based on MEMS torsional micro-mirror is introduced, including MEMS torsional micro-mirror and optical signal detection. The micro-mirror is a non-symmetric one, which means that the torsional bar supporting the micro-mirror is not located in the axis where the center of the micro-mirror locates. The optical signal detection is composed of PIN diode and dual fiber collimator, which is very sensitive to the coupling angle between the input fiber and output fiber. The detection principle is that acceleration is first transformed into torsional angle of the micro-mirror, then, optical insertion loss of the dual fiber collimator caused by the angle can be received by PIN. So under the flow of acceleration to torsional angle to optical signal attenuation to optical power detection, the acceleration is detected. The theory about sensing and optical signal detect of the device are discussed in this paper. The sensitive structure parameters and performance parameters are calculated by MATLAB. To simulate the static and modal analysis, the finite element analysis, ANSYS, is employed. Based on the above calculation, several optimization methods and the final structure parameters are given. The micro-mirror is completed by using silicon-glass bonding and deep reactive ion etching (DRIE). In the experiment, the acceleration is simulated by electrostatic force and the test results show that the static acceleration detection agrees with the theory analysis very well.

  19. Oophoropexy to prevent adnexal torsion: how, when, and for whom?

    PubMed

    Fuchs, Noga; Smorgick, Noam; Tovbin, Yoseph; Ben Ami, Ido; Maymon, Ron; Halperin, Reuvit; Pansky, Moty

    2010-01-01

    To assess the efficacy of oophoropexy in obviating recurrent torsion and its possible long-term effects. Case series and review of the literature (Canadian Task Force classification III). University hospital. Women who underwent oophoropexy for recurrent torsion of normal adnexa between 2003 and 2008. Retrieved information included the indication for oophoropexy, surgical methods, recurrence, and follow-up. Seven women underwent oophoropexy during the study period because of recurrent torsion of normal adnexa. One additional patient had experienced 3 torsion events of cystic adnexa. Surgical methods included suturing of the ovary to the pelvic sidewall or to the round ligament and plication of the utero-ovarian ligaments. Recurrence occurred in 1 of 6 patients for whom follow-up was available. All 6 patients reported spontaneous menstruation, and 2 conceived spontaneously and gave birth. Ultrasound at long-term follow-up (9-58 months) demonstrated normal ovaries. Oophoropexy seems to be efficacious in preventing recurrent torsion. It is our impression that plication of the utero-ovarian ligaments has advantages over other approaches insofar as surgical feasibility and anatomical conservation. Copyright 2010 AAGL. Published by Elsevier Inc. All rights reserved.

  20. 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.

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

    NASA Technical Reports Server (NTRS)

    Bonacuse, Peter J.; Kalluri, Sreeramesh

    1995-01-01

    The results are reported for high-temperature axial and torsional low-cycle fatigue experiments performed at 760 C in air on thin-walled tubular specimens of Haynes 188, a wrought cobalt-based superalloy. Data are also presented for mean 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. This 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 Code), Manson-Halford, modified multiaxiality factor (proposed in this paper), 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.

  2. 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.

  3. Bending and torsional flexibility of G/C-rich sequences as determined by cyclization assays.

    PubMed

    Dlakic, M; Harrington, R E

    1995-12-15

    The structural polymorphism of DNA is a vital aspect of its biological function. However, it has become increasingly apparent in recent years that DNA polymorphism is a complicated, multidimensional phenomenon that includes not only static sequence-directed structures but dynamic effects as well, including influences of counterions and sequence context. In order to address some of these additional factors that govern DNA conformation, we have used T4 ligase-mediated cyclization to investigate bending in a series of DNA sequences containing the GGGCCC.GGGCCC motif in different sequence contexts including various helical phasings with (A)5-tracts. We present evidence for curvature in GGGCCC.GGGCCC and (A)5-tract motifs in the presence of physiological levels of Mg2+ and show that these motifs curve through similar but oppositely directed bending angles under these ionic strength conditions. Although these two sequence motifs appear to bend similarly, our results suggest significant differences in stiffness and stability of curvature between them. We also show that under the same experimental conditions, the CTAG-CTAG sequence element possesses unusual torsional flexibility and that this appears to be associated with the central TA.TA dinucleotide. The results underscore the need to include sequence context and specific ion effects as well as a dynamic basis in more complete predictive models for functionally related DNA polymorphism.

  4. A novel TRPM8 agonist relieves dry eye discomfort.

    PubMed

    Yang, Jee Myung; Li, Fengxian; Liu, Qin; Rüedi, Marco; Wei, Edward Tak; Lentsman, Michael; Lee, Hyo Seok; Choi, Won; Kim, Seong Jin; Yoon, Kyung Chul

    2017-06-26

    Physical cooling of the eye surface relieves ocular discomfort, but translating this event to drug treatment of dry eye discomfort not been studied. Here, we synthesized a water-soluble TRPM8 receptor agonist called cryosim-3 (C3, 1-diisopropylphosphorylnonane) which selectively activates TRPM8 (linked to cooling) but not TRPV1 or TRPA1 (linked to nociception) and tested C3 in subjects with mild forms of dry eye disease. A set of 1-dialkylphosphoryalkanes were tested for activation of TRPM8, TRPV1 and TRPA1 receptors in transfected cells. The bioactivity profiles were compared by perioral, topical, and intravenous delivery to anesthetized rats. The selected lead candidate C3 or vehicle (water) was applied with a cotton gauze pad to upper eyelids of patients with dry eye disease (n = 30). Cooling sensation, tear film break-up time (TBUT), basal tear secretion, and corneal staining were evaluated. C3 was then applied four times daily for 2 weeks to patients using a pre-loaded single unit applicator containing 2 mg/mL of C3 in water (n = 20) or water only. TBUT, basal tear secretion, and corneal staining, and three questionnaires surveys of ocular discomfort (VAS scale, OSDI, and CVS symptoms) were analyzed before and at 1 and 2 weeks thereafter. C3 was a selective and potent TRPM8 agonist without TRPV1 or TRPA1 activity. In test animals, the absence of shaking behavior after C3 perioral administration made it the first choice for further study. C3 increased tear secretion in an animal model of dry eye disease and did not irritate when wiped on eyes of volunteers. C3 singly applied (2 mg/ml) produced significant cooling in <5 min, an effecting lasting 46 min with an increase in tear secretion for 60 min. C3 applied for 2 weeks also significantly increased basal tear secretion with questionnaire surveys of ocular discomfort indices clearly showing improvement of symptoms at 1 and 2 weeks. No complaints of irritation or pain were reported by any subject. C3

  5. 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

  6. 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

  7. 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.

  8. Chromatin Fiber Dynamics under Tension and Torsion

    PubMed Central

    Lavelle, Christophe; Victor, Jean-Marc; Zlatanova, Jordanka

    2010-01-01

    Genetic and epigenetic information in eukaryotic cells is carried on chromosomes, basically consisting of large compact supercoiled chromatin fibers. Micromanipulations have recently led to great advances in the knowledge of the complex mechanisms underlying the regulation of DNA transaction events by nucleosome and chromatin structural changes. Indeed, magnetic and optical tweezers have allowed opportunities to handle single nucleosomal particles or nucleosomal arrays and measure their response to forces and torques, mimicking the molecular constraints imposed in vivo by various molecular motors acting on the DNA. These challenging technical approaches provide us with deeper understanding of the way chromatin dynamically packages our genome and participates in the regulation of cellular metabolism. PMID:20480035

  9. Torsion-balance experiments and ultra-low-mass fields

    NASA Astrophysics Data System (ADS)

    Terrano, William

    2017-01-01

    Many of the solutions to outstanding problems in modern cosmology posit new, ultra-light fields. Unifying General Relativity and Quantum Mechanics appears to require new ultra-light fields at some level. Such fields are also invoked to drive inflation and dark energy. Ultra-light fields may also make up much or all of the dark matter density of the universe. Torsion pendulums, a technology that dates to the 18th century, remain one of the most sensitive experimental techniques to search for ultra-light, weakly interacting fields. I will explain how torsion balance experiments can search for beyond-the-standard-model fields using laboratory-based as well as galactic sources, and the important cosmological implications of these measurements. I will also describe a new experimental signature for which certain torsion balance geometries make very sensitive direct dark matter detectors over a broad range of interesting dark matter parameter space.

  10. The geometro-hydrodynamical representation of the torsion field

    NASA Astrophysics Data System (ADS)

    Trukhanova, Mariya, Iv.

    2017-09-01

    We construct the geometro-hydrodynamical formalism for a spinning particle based on the six-dimensional manifold of autoparallelism geometry which is represented as a vector bundle with a base formed by the manifold of the translational coordinates and a fiber specified at each point by the field of an orthogonal coordinate frame underlying the classical spin. We show that the geometry of oriented points leads to the existence of torsion field with the source - the classical spin. We expand the geometro-hydrodynamical representation of Pauli field developed by Takabayasi and Vigier. We show that the external torsion field has a force effect on the velocity and spin fields via the spin-vorticity, which is characteristic of the space structure with the inhomogene triad field. The possible experimental effects of torsion field are discussed.

  11. 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

  12. Torsional wave propagation in multiwalled carbon nanotubes using nonlocal elasticity

    NASA Astrophysics Data System (ADS)

    Arda, Mustafa; Aydogdu, Metin

    2016-03-01

    Torsional wave propagation in multiwalled carbon nanotubes is studied in the present work. Governing equation of motion of multiwalled carbon nanotube is obtained using Eringen's nonlocal elasticity theory. The effect of van der Waals interaction coefficient is considered between inner and outer nanotubes. Dispersion relations are obtained and discussed in detail. Effect of nonlocal parameter and van der Waals interaction to the torsional wave propagation behavior of multiwalled carbon nanotubes is investigated. It is obtained that torsional van der Waals interaction between adjacent tubes can change the rotational direction of multiwalled carbon nanotube as in-phase or anti-phase. The group and escape velocity of the waves converge to a limit value in the nonlocal elasticity approach.

  13. 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.

  14. BCN nanotubes as highly sensitive torsional electromechanical transducers.

    PubMed

    Garel, Jonathan; Zhao, Chong; Popovitz-Biro, Ronit; Golberg, Dmitri; Wang, Wenlong; Joselevich, Ernesto

    2014-11-12

    Owing to their mechanically tunable electronic properties, carbon nanotubes (CNTs) have been widely studied as potential components for nanoelectromechanical systems (NEMS); however, the mechanical properties of multiwall CNTs are often limited by the weak shear interactions between the graphitic layers. Boron nitride nanotubes (BNNTs) exhibit a strong interlayer mechanical coupling, but their high electrical resistance limits their use as electromechanical transducers. Can the outstanding mechanical properties of BNNTs be combined with the electromechanical properties of CNTs in one hybrid structure? Here, we report the first experimental study of boron carbonitride nanotube (BCNNT) mechanics and electromechanics. We found that the hybrid BCNNTs are up to five times torsionally stiffer and stronger than CNTs, thereby retaining to a large extent the ultrahigh torsional stiffness of BNNTs. At the same time, we show that the electrical response of BCNNTs to torsion is 1 to 2 orders of magnitude higher than that of CNTs. These results demonstrate that BCNNTs could be especially attractive building blocks for NEMS.

  15. Torsion Strain Effects on Critical Currents of Hts Superconducting Tapes

    NASA Astrophysics Data System (ADS)

    Takayasu, Makoto; Minervini, Joseph V.; Bromberg, Leslie

    2010-04-01

    A torsional twist strain effect on the critical current of a thin HTS tape has been found to be well described by a longitudinal strain model taking into account the internal shortening compressive strains accompanied with the tensile longitudinal strains due to a torsional twist. The critical current of a twisted tape is given by the integration of the critical current densities corresponding to the strain distribution over the tape cross-section using axial strain data of the tape. The model is supported with experimental results of YBCO and BSCCO-2223 tapes. It has been also found that torsional twisting effects on the critical currents of a tape composing of the conventional lapped-tape cable and the twisted stacked-tape cable are described by the same equation as that of a twisted single tape.

  16. FREQUENCY FILTERING OF TORSIONAL ALFVEN WAVES BY CHROMOSPHERIC MAGNETIC FIELD

    SciTech Connect

    Fedun, V.; Erdelyi, R.; Verth, G.; Jess, D. B.

    2011-10-20

    In this Letter, we demonstrate how the observation of broadband frequency propagating torsional Alfven waves in chromospheric magnetic flux tubes can provide valuable insight into their magnetic field structure. By implementing a full nonlinear three-dimensional magnetohydrodynamic numerical simulation with a realistic vortex driver, we demonstrate how the plasma structure of chromospheric magnetic flux tubes can act as a spatially dependent frequency filter for torsional Alfven waves. Importantly, for solar magnetoseismology applications, this frequency filtering is found to be strongly dependent on magnetic field structure. With reference to an observational case study of propagating torsional Alfven waves using spectroscopic data from the Swedish Solar Telescope, we demonstrate how the observed two-dimensional spatial distribution of maximum power Fourier frequency shows a strong correlation with our forward model. This opens the possibility of beginning an era of chromospheric magnetoseismology, to complement the more traditional methods of mapping the magnetic field structure of the solar chromosphere.

  17. Determining Angle of Humeral Torsion Using Image Software Technique

    PubMed Central

    Sethi, Madhu; Vasudeva, Neelam

    2016-01-01

    Introduction Several researches have been done on the measurement of angles of humeral torsion in different parts of the world. Previously described methods were more complicated, not much accurate, cumbersome or required sophisticated instruments. Aim The present study was conducted with the aim to determine the angles of humeral torsion with a newer simple technique using digital images and image tool software. Materials and Methods A total of 250 dry normal adult human humeri were obtained from the bone bank of Department of Anatomy. The length and mid-shaft circumference of each bone was measured with the help of measuring tape. The angle of humeral torsion was measured directly from the digital images by the image analysis using Image Tool 3.0 software program. The data was analysed statistically with SPSS version 17 using unpaired t-test and Spearman’s rank order correlation coefficient. Results The mean angle of torsion was 64.57°±7.56°. On the right side it was 66.84°±9.69°, whereas, on the left side it was found to be 63.31±9.50°. The mean humeral length was 31.6 cm on right side and 30.33 cm on left side. Mid shaft circumference was 5.79 on right side and 5.63 cm on left side. No statistical differences were seen in angles between right and left humeri (p>0.001). Conclusion From our study, it was concluded that circumference of shaft is inversely proportional to angle of humeral torsion. The length and side of humerus has no relation with the humeral torsion. With advancement of digital technology, it is better to use new image softwares for anatomical studies. PMID:27891326

  18. Deep learning methods for protein torsion angle prediction.

    PubMed

    Li, Haiou; Hou, Jie; Adhikari, Badri; Lyu, Qiang; Cheng, Jianlin

    2017-09-18

    Deep learning is one of the most powerful machine learning methods that has achieved the state-of-the-art performance in many domains. Since deep learning was introduced to the field of bioinformatics in 2012, it has achieved success in a number of areas such as protein residue-residue contact prediction, secondary structure prediction, and fold recognition. In this work, we developed deep learning methods to improve the prediction of torsion (dihedral) angles of proteins. We design four different deep learning architectures to predict protein torsion angles. The architectures including deep neural network (DNN) and deep restricted Boltzmann machine (DRBN), deep recurrent neural network (DRNN) and deep recurrent restricted Boltzmann machine (DReRBM) since the protein torsion angle prediction is a sequence related problem. In addition to existing protein features, two new features (predicted residue contact number and the error distribution of torsion angles extracted from sequence fragments) are used as input to each of the four deep learning architectures to predict phi and psi angles of protein backbone. The mean absolute error (MAE) of phi and psi angles predicted by DRNN, DReRBM, DRBM and DNN is about 20-21° and 29-30° on an independent dataset. The MAE of phi angle is comparable to the existing methods, but the MAE of psi angle is 29°, 2° lower than the existing methods. On the latest CASP12 targets, our methods also achieved the performance better than or comparable to a state-of-the art method. Our experiment demonstrates that deep learning is a valuable method for predicting protein torsion angles. The deep recurrent network architecture performs slightly better than deep feed-forward architecture, and the predicted residue contact number and the error distribution of torsion angles extracted from sequence fragments are useful features for improving prediction accuracy.

  19. Impact of torsion and stretching on the thermal conductivity of polyethylene strands

    NASA Astrophysics Data System (ADS)

    Tu, Runchun; Liao, Quanwen; Zeng, Lingping; Liu, Zhichun; Liu, Wei

    2017-03-01

    A single polyethylene chain was reported to have a high metal-like thermal conductivity (TC), which stands in sharp contrast to the thermally insulating feature of common bulk polyethylene materials. This work numerically investigates the impact of torsion and stretching on the TC of polyethylene strands by using equilibrium molecular dynamics simulations. The simulation results show that torsion slightly reduces the TC of a single polyethylene chain. In contrast, the heat conduction of polyethylene strands could be slightly enhanced under torsional loading with a specific torsional angle. Particularly, an apparent improvement of TC of polyethylene strands is achieved by combining torsion and stretching functions. It is found that the TC of torsional polyethylene strands is sensitive to torsional patterns. Our study proposes a specific torsional pattern of polyethylene strands that significantly enhances the heat conduction of the original counterpart. This study will play an essential role in guiding the improvements of thermal conduction property of polymers.

  20. Missed torsion in undescended testes detected by scintigraphy: testicular scintigraphy a decisive complementary tool.

    PubMed

    Kodali, Sunil Kumar; Abdullah, Zuhair Saleh; Sharma, Punit; Khan, Muhammad Umar; Naeem, Muhammad

    2013-01-01

    Torsion of undescended testis, although not uncommon, causes diagnostic difficulties. We here present testicular scintigraphy images of a typical case of torsion of an undescended inguinal testis with disparity between clinical and ultrasonography (USG) findings in the contralateral retractile testis.

  1. Free torsional vibrations of tapered cantilever I-beams

    NASA Astrophysics Data System (ADS)

    Rao, C. Kameswara; Mirza, S.

    1988-08-01

    Torsional vibration characteristics of linearly tapered cantilever I-beams have been studied by using the Galerkin finite element method. A third degree polynomial is assumed for the angle of twist. The analysis presented is valid for long beams and includes the effect of warping. The individual as well as combined effects of linear tapers in the width of the flanges and the depth of the web on the torsional vibration of cantilever I-beams are investigated. Numerical results generated for various values of taper ratios are presented in graphical form.

  2. 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.

  3. Torsional instability in suspension bridges: The Tacoma Narrows Bridge case

    NASA Astrophysics Data System (ADS)

    Arioli, Gianni; Gazzola, Filippo

    2017-01-01

    All attempts of aeroelastic explanations for the torsional instability of suspension bridges have been somehow criticised and none of them is unanimously accepted by the scientific community. We suggest a new nonlinear model for a suspension bridge and we perform numerical experiments with the parameters corresponding to the collapsed Tacoma Narrows Bridge. We show that the thresholds of instability are in line with those observed the day of the collapse. Our analysis enables us to give a new explanation for the torsional instability, only based on the nonlinear behavior of the structure.

  4. Torsionally excited methanol in hot molecular cloud cores

    NASA Technical Reports Server (NTRS)

    Menten, K. M.; Walmsley, C. M.; Henkel, C.; Wilson, T. L.; Snyder, L. E.; Hollis, J. M.

    1986-01-01

    Torsionally excited methanol lines were detected in the direction of four galactic molecular cloud regions by means of scans in the 20-24 GHz interval with the Effelsberg 100 m radiotelescope. Transitions in both the first torsionally excited state, with excitation energies of about 450 K, and the ground state were seen in the direction of the hot, molecular cloud cores of the Orion-KL region, W3(OH), NGC 7538 and W51. The emission in Orion originated from a hot region in the southern ridge cloud 4 arcsec from the hot core. The greatest deviations from LTE occurred when a strong compact continuum source was present.

  5. Portal venous thrombosis developing after torsion of a wandering spleen.

    PubMed

    Yilmaz, Ö; Kiziltan, R; Almali, N; Aras, A

    2017-03-01

    Torsion of a wandering spleen is a rare disease. The symptoms and signs of this condition are only present when the splenic pedicle torts. The etiological factors are the congenital absence of the ligaments that hold the spleen in its normal anatomic position, or the relaxation of these ligaments resulting from conditions like trauma and abdominal surgery. We aimed to present a rare case with torsion of wandering spleen that consequently developed thrombosis of portal vein and its branches, taking into consideration the relevant literature.

  6. Wandering spleen with chronic torsion in a patient with thalassaemia.

    PubMed

    Ho, Chi Long

    2014-12-01

    Wandering spleen or splenoptosis is an uncommon entity and often an asymptomatic finding of acute abdomen in the emergency department. A high index of suspicion for splenic torsion is required, particularly in patients with known splenomegaly, as this condition could potentially lead to splenic infarction. Recognition of this condition can help avoid potential confusion with acute abdomen of other aetiologies. Herein, we present a unique case of wandering spleen with chronic torsion, which, to the best of our knowledge, has never been described in an elderly patient with haemoglobin H thalassaemia. We also review the literature for the aetiology and pathogenesis of wandering spleen, and discuss the relevant diagnostic modalities and treatment options.

  7. 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.

  8. The Frequency of Torsional Vibration of a Tapered Beam

    NASA Technical Reports Server (NTRS)

    Coleman, Robert

    1939-01-01

    A solution for the equation of torsional vibration of tapered beams has been found in terms of Bessel functions for beams satisfying the following conditions: (a) the cross sections along the span are similar in shape; and (b) the torsional stiffness of a section can be expressed as a power of a linear function of distance along the span. The method of applying the analysis to actual cases has been described. Charts are given from which numerical values can be immediately obtained for most cases of practical importance. The theoretical values of the frequency ratio have been experimentally checked on five beams having different amounts of taper.

  9. Singularities and n-dimensional black holes in torsion theories

    NASA Astrophysics Data System (ADS)

    Cembranos, J. A. R.; Gigante Valcarcel, J.; Maldonado Torralba, F. J.

    2017-04-01

    In this work we have studied the singular behaviour of gravitational theories with non symmetric connections. For this purpose we introduce a new criteria for the appearance of singularities based on the existence of black/white hole regions of arbitrary codimension defined inside a spacetime of arbitrary dimension. We discuss this prescription by increasing the complexity of the particular torsion theory under study. In this sense, we start with Teleparallel Gravity, then we analyse Einstein-Cartan theory, and finally dynamical torsion models.

  10. Hydrogen embrittlement of 45 steel in electrolytes in torsion

    SciTech Connect

    Marichev, V.A.

    1987-07-01

    The authors investigate the influence of electrochemical polarization on corrosion crack growth in corrosion cracking of high-strength steel during torsion. It was established that anodic polarization has practically no influence on the crack growth rate while cathodic accelerates crack growth. Crack growth at the corrosion potentials in NaCl solution is eased significantly more than in CrO/sub 3/ solution. Hydrogen embrittlement makes a larger contribution to the corrosion cracking mechanism of 45 high-strength steel in torsion than in tension.

  11. Massless fermions and Kaluza--Klein theory with torsion

    SciTech Connect

    Wu, Y.; Zee, A.

    1984-09-01

    A pure Kaluza--Klein theory contains no massless fermion in four-dimensional theory. We investigate the effect of introducing torsion on the internal manifold and find that there are massless fermions. The hope is that given an isometry group the representation to which these fermions belong is fixed, in contrast to the situation in Yang--Mills theory. We show that this is indeed the case, but the representations do not appear to be the ones favored by current theoretical prejudice. The cases with parallelizable torsions on a group manifold as the internal manifold are analyzed in detail.

  12. Torsion Testing of Diffusion Bonded LIGA Formed Nickel

    SciTech Connect

    Buchheit, T.E.; Christenson, T.R.; Schmale, D.T.

    1999-01-27

    A test technique has been devised which is suitable for the testing of the bond strength of batch diffusion bonded LIGA or DXRL defined structures. The method uses a torsion tester constructed with the aid of LIGA fabrication and distributed torsion specimens which also make use of the high aspect ratio nature of DXRL based processing. Measurements reveal achieved bond strengths of 130MPa between electroplated nickel with a bond temperature of 450 C at 7 ksi pressure which is a sufficiently low temperature to avoid mechanical strength degradation.

  13. A monolithically integrated torsional CMOS-MEMS relay

    NASA Astrophysics Data System (ADS)

    Riverola, M.; Sobreviela, G.; Torres, F.; Uranga, A.; Barniol, N.

    2016-11-01

    We report experimental demonstrations of a torsional microelectromechanical (MEM) relay fabricated using the CMOS-MEMS approach (or intra-CMOS) which exploits the full foundry inherent characteristics enabling drastic reduction of the fabrication costs and batch production. In particular, the relay is monolithically integrated in the back end of line of a commercial standard CMOS technology (AMS 0.35 μm) and released by means of a simple one-step mask-less wet etching. The fabricated torsional relay exhibits an extremely steep switching behaviour symmetrical about both contact sides with an on-state contact resistance in the k Ω -range throughout the on-off cycling test.

  14. 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.

  15. Torsion of a neoplastic intrascrotal testis: when the torsion reveals the mass. A case report and review.

    PubMed

    Albino, Giuseppe; Nenna, Rosanna; Corvasce, Antonio; Marucco, Ettore Cirillo

    2012-12-01

    Cases of torsion of the spermatic cord are rare in men over 30-years-old. Testicular tumors manifest themselves rarely with symptoms of acute scrotum. We report the case of a 38-years-old patient who presented for a suspected left testis torsion. On examination, the testicle was markedly increased in size and painful. The manual derotation made pain dramatically disappear. He came to our attention after about a month asking for an orchidopexy. During the surgery a biopsy was performed. The diagnosis was a Yolk Sac Tumor. A radical inguinal orchiectomy was performed with left hemiscrotal excision, "in block". He performed four cycles of chemotherapy and with no recurrence after 12 months of follow-up. In literature only seven cases of torsion of an intrascrotal testicle with cancer are reported. Our case is the eighth one.

  16. Tension/torsion loading of composite laminates with free-edge boundary conditions

    NASA Technical Reports Server (NTRS)

    Hooper, Steven J.; Hagemeier, Rick; Ramaprasad, Srinivasan

    1991-01-01

    A finite element analysis of a family of quasi-isotropic graphite/epoxy laminates was conducted for tension, torsion, and combined tension/torsion loading. The model was employed to investigate the effects of delaminations on torsional stiffness and also to evaluate the total strain energy release rates associated with these delaminations.

  17. Left common basal pyramid torsion following left upper lobectomy/segmentectomy.

    PubMed

    Wang, Wei-Li; Cheng, Yen-Po; Cheng, Ching-Yuan; Wang, Bing-Yen

    2015-05-01

    Lobar or segmental lung torsion is a severe complication of lung resection. To the best of our knowledge, common basal pyramid torsion has never been reported. We describe a case of left basal pyramid torsion after left upper lobectomy and superior segmentectomy, which was successfully treated by thoracoscopic surgery.

  18. 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.

  19. 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 ...

  20. 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)

  1. 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.

  2. 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).

  3. 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.

  4. Protective role of erythropoietin during testicular torsion of the rats.

    PubMed

    Yazihan, Nuray; Ataoglu, Haluk; Koku, Naim; Erdemli, Esra; Sargin, Ayse Kose

    2007-10-01

    Testicular torsion is an important clinical urgency. Similar mechanisms occurred after detorsion of the affected testis as in the ischemia reperfusion (I/R) damage. This study was designed to investigate the effects of erythropoietin (EPO) treatment after unilateral testicular torsion. Fifty male Sprague-Dawley rats were divided into five groups. Group 1 underwent a sham operation of the right testis under general anesthesia. Group 2 was same as sham, and EPO (3,000 IU/kg) infused i.p., group 3 underwent a similar operation but the right testis was rotated 720 degrees clockwise for 1 h, maintained by fixing the testis to the scrotum, and saline infused during the procedure. Group 4 underwent similar torsion but EPO was infused half an hour before the detorsion procedure, and in group 5, EPO was infused after detorsion procedure. Four hours after detorsion, ipsilateral and contralateral testes were taken out for evaluation. Treatment with EPO improved testicular structures in the ipsilateral testis but improvement was less in the contralateral testis histologically, but EPO treatment decreased germ cell apoptosis in both testes following testicular IR. TNF-alpha, IL-1beta, IL-6 and nitrite levels decreased after EPO treatment especially in the ipsilateral testis. We conclude that testicular I/R causes an increase in germ cell apoptosis both in the ipsilateral and contralateral testes. Erythropoietin has antiapoptotic and anti-inflammatory effects following testicular torsion.

  5. Contralateral genitofemoral sympathetic nerve discharge increases following ipsilateral testicular torsion.

    PubMed

    Otçu, Selçuk; Durakoğugil, Murat; Orer, Hakan S; Tanyel, Feridun C

    2002-10-01

    The decrease in blood flow due to the activation of sympathetic system has been suggested to play a role in contralateral testicular deterioration associated with unilateral testicular torsion. Sympathetic nerve discharges (SND) from the genitofemoral nerve were evaluated before and during unilateral testicular torsion. Under urethane anesthesia, arterial blood pressure and SND from splanchnic and right genitofemoral nerves were recorded in 12 male Sprague-Dawley rats, 8 of which were included in subsequent analyses. After control recordings of basal discharges for 2 min the left testis was twisted 720 degrees counterclockwise, and recording was resumed for an additional 30 min. Changes in nerve activity were calculated by measuring the area under the autospectrum curve, and alterations were compared. Following testicular torsion no significant changes were obtained for splanchnic SND, but the amplitude of SND from contralateral genitofemoral nerve showed an overall increase of 21.20+/-7.03% in six rats. This increase lasted about 10-15 min and activities returned to pretorsion levels. In two other rats no significant change was observed in either splanchnic or genitofemoral SND. Ipsilateral testicular torsion results in a transient increase in genitofemoral SND. A possible autonomic reflex mechanism may exist, and it may be activated by noxious stimuli from contralateral side. This reflex mechanism may initiate a series of events that lead to the injury of contralateral testis.

  6. 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.

  7. 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

  8. 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.

  9. Ectopic ovary with torsion: uncommon diagnosis made by ultrasound

    PubMed Central

    Castro, Adham do Amaral e; Morandini, Fernando; Calixto, Caroline Paludo; Barros, Wagner Haese; Nakatani, Edson Tetsuya; Castro, Allan do Amaral e

    2017-01-01

    Ultrasound is an important diagnostic tool in inguinal hernia and in the evaluation of the contents of the hernia sac. This report presents a case in which ultrasound revealed a herniated ectopic ovary, complicated by torsion of its vascular pedicle, in the right labia majora. We also present a brief discussion of ovarian hernia, its potential complications, and the treatments available. PMID:28298734

  10. Ectopic ovary with torsion: uncommon diagnosis made by ultrasound.

    PubMed

    Castro, Adham do Amaral E; Morandini, Fernando; Calixto, Caroline Paludo; Barros, Wagner Haese; Nakatani, Edson Tetsuya; Castro, Allan do Amaral E

    2017-01-01

    Ultrasound is an important diagnostic tool in inguinal hernia and in the evaluation of the contents of the hernia sac. This report presents a case in which ultrasound revealed a herniated ectopic ovary, complicated by torsion of its vascular pedicle, in the right labia majora. We also present a brief discussion of ovarian hernia, its potential complications, and the treatments available.

  11. Angle of torsion of the femur and its correlates.

    PubMed

    Prasad, R; Vettivel, S; Isaac, B; Jeyaseelan, L; Chandi, G

    1996-01-01

    Unpaired femora (171), devoid of gross pathology and grouped by gender (94 male and 77 female) and side (88 left and 83 right), were used to measure the angle of femoral torsion and the maximum femur length and to score the degree of prominency of the superior cervical tubercle, intertrochanteric line, quadrate tubercle, linea aspera, and adductor tubercle. The angle of torsion ranged from -9 to +35 degrees with a mean of +12.3 degrees. The means were not significantly different either by gender or side. The angle correlated negatively with superior cervical tubercle, intertrochanteric line, and adductor tubercle (P < 0.001), positively with quadrate tubercle (P < 0.001) but not with linea aspera, neck-shaft angle, or length of femur. Bony prominences were significantly more apparent in males. There was no significant association between prominency and side. The torsion seems to be brought about by muscular activity and capsular and ligamentous strain at the hip. This study suggests to clinicians the possibility of correction of torsion defects in certain hip diseases of growing children by suitable alteration in posture of the lower extremity.

  12. 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…

  13. 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.

  14. 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…

  15. The human ocular torsion position response during yaw angular acceleration.

    PubMed

    Smith, S T; Curthoys, I S; Moore, S T

    1995-07-01

    Recent results by Wearne [(1993) Ph.D. thesis] using the scleral search-coil method of measuring eye position indicate that changes in ocular torsion position (OTP) occur during yaw angular acceleration about an earth vertical axis. The present set of experiments, using an image processing method of eye movement measurement free from the possible confound of search coil slippage, demonstrates the generality and repeatability of this phenomenon and examines its possible causes. The change in torsion position is not a linear vestibulo-ocular reflex (LVOR) response to interaural linear acceleration stimulation of the otoliths, but rather the effect is dependent on the characteristics of the angular acceleration stimulus, commencing at the onset and decaying at the offset of the angular acceleration. In the experiments reported here, the magnitude of the angular acceleration stimulus was varied and the torsion position response showed corresponding variations. We consider that the change in torsion position observed during angular acceleration is most likely to be due to activity of the semicircular canals.

  16. A Method of Calculating Bending Stresses Due to Torsion

    DTIC Science & Technology

    1942-12-01

    eaeh hay. The foundation for such general methods was laid by Boner in a comprehensive paper (reference l); subsequent authors h’nve followed Ebner...8217 B lead more or less closely.. Numerical calculations made by Boner nnd others lead to the conclusion that bending stresses due to torsion are of

  17. Long-wavelength torsional modes of solar coronal plasma structures

    NASA Astrophysics Data System (ADS)

    Vasheghani Farahani, S.; Nakariakov, V. M.; van Doorsselaere, T.

    2010-07-01

    Aims: We consider the effects of the magnetic twist and plasma rotation on the propagation of torsional m = 0 perturbations of cylindrical plasma structures (straight magnetic flux tubes) in the case when the wavelength is much longer than the cylinder diameter. Methods: The second order thin flux tube approximation is used to derive dispersion relations and phase relations in linear long-wavelength axisymmetric magnetohydrodynamic waves in uniformly twisted and rotating plasma structures. Results: Asymptotic dispersion relations linking phase speeds with the plasma parameters are derived. When twist and rotation are both present, the phase speed of torsional waves depends upon the direction of the wave propagation, and also the waves are compressible. The phase relations show that in a torsional wave the density and azimuthal magnetic field perturbations are in phase with the axial magnetic field perturbations and anti-phase with tube cross-section perturbations. In a zero-β non-rotating plasma cylinder confined by the equilibrium twist, the density perturbation is found to be about 66 percent of the amplitude of the twist perturbation in torsional waves.

  18. Toeplitz Operators, Analytic Torsion, and the Hypoelliptic Laplacian

    NASA Astrophysics Data System (ADS)

    Bismut, Jean-Michel

    2016-12-01

    The purpose of this paper is to explain how Toeplitz operators can be used in studying asymptotic torsion, and also in the theory of the hypoelliptic Laplacian. The role of the hypoelliptic Laplacian in the explicit computation of orbital integrals will be described. The geodesic flow will be viewed as implementing a dynamical version of Fourier transform.

  19. Development of Torsional and Linear Piezoelectrically Driven Motors

    NASA Technical Reports Server (NTRS)

    Duong, Khanh; Newton, David; Garcia, Ephrahim

    1996-01-01

    The development of rotary and linear inchworm-motors using piezoelectric actuators is presented. The motors' design has the advantage of a macro and micro stepper motor with high load and speed. The torsional design is capable of fast angular positioning with micro level accuracy. Additionally, the rotary motor, as designed, can be used as a clutch/brake mechanism. Constructed prototype motors of both types along with their characteristics are presented. The torsional motor consists of a torsional section that provides angular displacement and torque, and two alternating clamping sections which provide the holding force. The motor relies on the principal piezoelectric coupling coefficient (d33) with no torsional elements, increasing its torque capability. The linear motor consists of a longitudinal vibrator that provides displacement and load, and two alternating clamping sections which provide the holding force. This design eliminates bending moment, tension and shear applied to the actuator elements, increase its load capability and life. Innovative flexure designs have been introduced for both motor types. Critical issues that affect the design and performance of the motors are explored and discussed. Experiments are performed demonstrating the motor prototypes based on the aforementioned design considerations.

  20. The Rotation-Torsion Spectrum of CH_2DOH

    NASA Astrophysics Data System (ADS)

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

    2010-06-01

    Due to the asymmetry of the CH_2D group, the internal rotation problem in the partially deuterated species of methanol CH_2DOH is a complicated one as, unlike in the normal species CH_3OH, the inertia tensor depends on the angle of internal rotation. The CH_2DOH species also displays a dense far infrared torsional spectrum difficult to assign. Recently 38 torsional subbands of CH_2DOH have been identified, but for most of them there is neither an assignment nor an analysis of their rotational structure. In this paper an analysis of the rotation-torsion spectrum of CH_2DOH will be presented. The rotational structure of 23 torsional subbands have been assigned. These subbands are Δ v_t &ge 1 perpendicular subbands with a value of v'_t up to 10b and values of K' and K'' ranging from 0 to 9. For all subbands, the Q-branch was assigned, for 3 subbands, the R- and P-branches could also be found. The results of the rotational analysis with an expansion in J(J+1) of the new subbands and of already observed ones will be presented. When available, microwave lines within the lower torsional level, recorded in this work or already measured, were added to the data set. A theoretical approach aimed at calculating the rotation-torsion energy levels has also been developed. It is based on an expansion in terms of rotation-torsion operators with C_s symmetry and accounts for the dependence of the inertia tensor on the angle of internal rotation. This approach will be used to carry out a preliminary global analyses of the wavenumbers and of the frequencies. Lauvergnat, Coudert, Klee, and Smirnov, J. Mol. Spec. 256 (2009) 204. Quade, Liu, Mukhopadhyay, and Su, J. Mol. Spec. 192 (1998) 378; Mukhopadhyay, J. Mol. Struct. 695-696 (2004) 357. Liu and Quade, J. Mol. Spec. 146 (1991) 252 Mukhopadhyay et al., J. Chem. Phys. 116 (2002) 3710.

  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. The protective role of erdosteine on testicular tissue after testicular torsion and detorsion.

    PubMed

    Koc, Ahmet; Narci, Adnan; Duru, Mehmet; Gergerlioglu, H Serdar; Akaydin, Yesim; Sogut, Sadik

    2005-12-01

    Testicular torsion and detorsion are important clinical problems for infertile man and oxidative stress may have a role in this clinical situation. The aim of this study was to investigate the protective role of erdosteine, an antioxidant, on unilateral testicular reperfusion injury in rats. The rats were divided into four groups including seven rats in each group: control, torsion, torsion/detorsion and torsion/detorsion+erdosteine. Rats, except the sham operation group, were subjected to left unilateral torsion (720( composite function) rotation in the clockwise direction) without including the epididymis. The experiments were finished after sham operation time for control, 120 min torsion for torsion group and 120 min torsion and 240 min detorsion for torsion/detorsion groups. Bilateral orchiectomy was performed for all groups of rats. The ipsilateral and controlateral testis were divided into two pieces to analyse biochemical parameters and to investigate the light microscopic view. Malondialdehyde level of ipsilateral testis was increased in torsion and torsion/detorsion groups in comparison with the other groups (p < 0.05). Erdosteine treatment ameliorated lipid peroxidation after torsion/detorsion in ipsilateral testis (p < 0.05). Also, xanthine oxidase activity of ipsilateral testis was increased in torsion/detorsion group in comparison with the others (p < 0.05). Nitric oxide (NO) level of ipsilateral testis was higher in all experimental groups than sham operated control group (p < 0.05). Also, NO level of torsion group was increased in comparison with detorsion groups (p < 0.05). Erdosteine treatment caused increased glutathione peroxidase activity in comparison with torsion and torsion/detorsion groups and catalase activity in comparison with the other groups in ipsilateral testis (p < 0.05). Superoxide dismutase activity of ipsilateral testis was higher in torsion/detorsion and torsion/detorsion+erdosteine groups than control and torsion groups (p < 0

  3. Axial and torsional stiffness of pediatric prosthetic feet.

    PubMed

    Taboga, Paolo; Grabowski, Alena M

    2017-02-01

    Prosthetic stiffness likely affects the walking biomechanics of toddlers and children with leg amputations, but the actual stiffness values for prostheses are not reported by manufacturers or in standardized testing procedures. We measured axial (kA) and torsional (kT) stiffness from four brands of pediatric prosthetic feet (Trulife, Kingsley Mfg. Co., TRS Incorporated, and College Park Industries) over a range of foot sizes. We applied forces and torques onto prostheses with a materials testing machine that replicated those exhibited in vivo by using the kinetics measured from four non-amputee toddlers (2-3years) during walking. Across brands, kA averaged 35.2kN/m during heel loading, was more stiff during midfoot loading (121.8kN/m, P<0.001) and less stiff during forefoot loading (11.8kN/m, P=0.013). kA was similar across brands with no statistically significant effect of prosthetic foot size, with the exception of the TRS feet. Plantarflexion torsional stiffness (kT1), was not statistically different across brands. For every 1cm increase in foot size, kT1 increased 0.16kN·m/rad (P<0.001). College Park prostheses had 4.54kN·m/rad lower dorsiflexion torsional stiffness (kT2) (P<0.001) compared to other brands. For every 1cm increase in foot size, the kT2 applied on the foot increased 0.63kN·m/rad. The axial and torsional stiffness testing methods are reproducible and should be adopted by prosthetic foot manufacturers. Axial and torsional stiffness values of commercially available prosthetic feet should be publically reported to health practitioners to ensure evidence-based decisions and meet the specific needs of each patient with a leg amputation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Development of a Meso-Scale SMA-Based Torsion Actuator for Image-Guided Procedures.

    PubMed

    Sheng, Jun; Gandhi, Dheeraj; Gullapalli, Rao; Simard, J Marc; Desai, Jaydev P

    2017-02-01

    This paper presents the design, modeling, and control of a meso-scale torsion actuator based on shape memory alloy (SMA) for image-guided surgical procedures. Developing a miniature torsion actuator is challenging, but it opens the possibility of significantly enhancing the robot agility and maneuverability. The proposed torsion actuator is bi-directionally actuated by a pair of antagonistic SMA torsion springs through alternate Joule heating and natural cooling. The torsion actuator is integrated into a surgical robot prototype to demonstrate its working performance in the humid environment under C-Arm CT image guidance.

  5. The torsional mechanical properties of copper nanowires supported by carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Huan, Hao; Fu, Bing; Ye, Xiang

    2017-02-01

    The torsional mechanical properties of hollow Cu nanowires supported by carbon nanotubes (CNTs) are studied by all atoms molecular dynamic simulation. It is found that the critical angles of Cu nanowires almost do not decrease when the temperature increases to a limit value, and this invariant feature also has been found as the torsional loading rate is lower than 4.5 ×1012 °s-1. Due to the support of CNTs, Cu nanowires can bear larger torsional angle at low torsional rates and high temperatures compared with those without CNTs, which means the CNTs will increase the torsion-tolerance of Cu nanowires.

  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. Reliever salbutamol use as a measure of exacerbation risk in chronic obstructive pulmonary disease.

    PubMed

    Jenkins, Christine R; Postma, Dirkje S; Anzueto, Antonio R; Make, Barry J; Peterson, Stefan; Eriksson, Göran; Calverley, Peter M

    2015-08-21

    Debate exists regarding which endpoints most sensitively reflect day-to-day variation in chronic obstructive pulmonary disease (COPD) symptoms and are most useful in clinical practice to predict COPD exacerbations. We hypothesized that short-acting β2-agonist (SABA) reliever use would predict short- and long-term exacerbation risk in COPD patients. We performed a retrospective analysis of data from a study (ClinicalTrials.gov registration: NCT00419744) comparing budesonide/formoterol 320/9 μg with formoterol 9 μg (both twice daily) in patients with moderate-to-very-severe COPD; reliever salbutamol 90 μg was provided. First occurrence of reliever use >4 (low), >10 (medium), and >20 (high) inhalations/day was assessed as a predictor of short-term (3-week) exacerbation risk. Mean daily reliever use in the week preceding the 2-month visit was investigated as a predictor of the long-term (10-month) exacerbation risk, using intervals of 2-5, 6-9, and ≥10 inhalations/day. Overall, 810 patients were included (61 % male; mean age 63.2 years; post-bronchodilator forced expiratory volume in 1 s 37.7 % of predicted). First occurrence of low, medium, or high reliever use was predictive of an exacerbation within the following 3 weeks; exacerbation risk increased significantly with increasing reliever use. Mean reliever use over 1 week was predictive of long-term exacerbation risk. Patients with mean use of 2-5, 6-9, and ≥10 inhalations/day exhibited 21 %, 67 %, and 135 % higher exacerbation rates, respectively, in the following 10 months, compared with <2 inhalations/day. Budesonide/formoterol was associated with lower short- and long-term exacerbation risk than formoterol in all reliever-use groups. SABA reliever use is a predictor of short- and long-term exacerbation risk in moderate-to-very-severe COPD patients with a history of exacerbations receiving budesonide/formoterol or formoterol.

  9. 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.

  10. 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.

  11. Torsion, parity-odd response, and anomalies in topological states

    NASA Astrophysics Data System (ADS)

    Parrikar, Onkar; Hughes, Taylor L.; Leigh, Robert G.

    2014-11-01

    We study the response of a class of topological systems to electromagnetic and gravitational sources, including torsion and curvature. By using the technology of anomaly polynomials, we derive the parity-odd response of a massive Dirac fermion in d =2 +1 and d =4 +1 , which provides a simple model for a topological insulator. We discuss the covariant anomalies of the corresponding edge states, from a Callan-Harvey anomaly inflow, as well as a Hamiltonian spectral flow point of view. We also discuss the applicability of our results to other systems such as Weyl semimetals. Finally, using dimensional reduction from d =4 +1 , we derive the effective action for a d =3 +1 time-reversal invariant topological insulator in the presence of torsion and curvature, and discuss its various physical consequences.

  12. Torsion of a Wandering Spleen Presenting as Acute Abdomen

    PubMed Central

    Chauhan, Narvir Singh; Kumar, Satish

    2016-01-01

    Summary Background Wandering spleen is a rare condition which if uncorrected, can result in torsion and infarction. Clinical presentation of a wandering spleen can vary from asymptomatic abdominal mass to acute abdominal pain. Radiological investigations play a pivotal role in diagnosis as the clinical diagnosis is usually impossible. Case Report We present a case of wandering spleen with torsion and complete infarction that occurred in a 32-year-old multiparous female. The diagnosis was established preoperatively on colour Doppler and CT of the abdomen with subsequent confirmation on surgery. Conclusions Wandering spleen is a rare clinical condition which can present as acute abdomen. An increased awareness of this entity together with the timely use of ultrasound and CT of the abdomen can play an important role in preoperative diagnosis and surgical management. PMID:27057261

  13. Wandering spleen with chronic torsion in a patient with thalassaemia

    PubMed Central

    Ho, Chi Long

    2014-01-01

    Wandering spleen or splenoptosis is an uncommon entity and often an asymptomatic finding of acute abdomen in the emergency department. A high index of suspicion for splenic torsion is required, particularly in patients with known splenomegaly, as this condition could potentially lead to splenic infarction. Recognition of this condition can help avoid potential confusion with acute abdomen of other aetiologies. Herein, we present a unique case of wandering spleen with chronic torsion, which, to the best of our knowledge, has never been described in an elderly patient with haemoglobin H thalassaemia. We also review the literature for the aetiology and pathogenesis of wandering spleen, and discuss the relevant diagnostic modalities and treatment options. PMID:25630326

  14. 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.

  15. Bending-torsion flutter calculations modified by subsonic compressibility corrections

    NASA Technical Reports Server (NTRS)

    Garrick, I E

    1946-01-01

    A number of calculations of bending-torsion wing flutter are made at two Mach numbers, m=0 (incompressible case) and m=0.7, and results are compared. The air forces employed for the case of m=0.7 are based on Frazer's recalculation of Possio's results, which are derived on the assumption of small disturbances to the main flow. For ordinary wings of normal density and of low bending frequency in comparison with torsion frequency, the compressibility correction to the flutter speed appears to be of the order of a few percent; whereas the correction to flutter speed for high-density wing sections, such as propeller sections, and to the wing-divergence speed in general, may be based on a rule using the (1 - m(2))1/4 factor and, for m=0.7, represents a decrease of the order of 17 percent.

  16. Triaxial and Torsional Shear Test Results for Sand

    DTIC Science & Technology

    1994-06-01

    iia 3 -1 40- -10 - , 10 - al 0 z 30 100- 0 -0.1 -0.08 .0.06 -0.04 -0.02 0 0.02 0.04 0.06 AXIAL STRAIN (%) F01 . w Ir 97 LL- -01U..-.6 .. 4 02000 .400...3.2.13 Hollow Cylinder Cyclic Torsional Shear Test (NKIOCU50) NK1 OCU5O UNDRAINED STRESS CONTROLLED TORSIONAL SHEAR TEST 200 100 000 W 00 E 0 0z 00 0...so 0 so 0 60 0 so 0 90 0 00 0 Angle in ir Plane (Degree) Figure 3.3.5 Hollow Cylinder Rotational Shear Test (NR4OCU5O) NR56CUSO: UNDRAINED STRESS

  17. 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.

  18. Torsional Newton-Cartan geometry from the Noether procedure

    NASA Astrophysics Data System (ADS)

    Festuccia, Guido; Hansen, Dennis; Hartong, Jelle; Obers, Niels A.

    2016-11-01

    We apply the Noether procedure for gauging space-time symmetries to theories with Galilean symmetries, analyzing both massless and massive (Bargmann) realizations. It is shown that at the linearized level the Noether procedure gives rise to (linearized) torsional Newton-Cartan geometry. In the case of Bargmann theories the Newton-Cartan form Mμ couples to the conserved mass current. We show that even in the case of theories with massless Galilean symmetries it is necessary to introduce the form Mμ and that it couples to a topological current. Further, we show that the Noether procedure naturally gives rise to a distinguished affine (Christoffel type) connection that is linear in Mμ and torsionful. As an application of these techniques we study the coupling of Galilean electrodynamics to TNC geometry at the linearized level.

  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. A torsional artificial muscle from twisted nitinol microwire

    NASA Astrophysics Data System (ADS)

    Mirvakili, Seyed M.; Hunter, Ian W.

    2017-04-01

    Nitinol microwires of 25 μm in diameter can have tensile actuation of up to 4.5% in less than 100 ms. A work density of up to 480 MPa can be achieved from these microwires. In the present work, we are showing that by twisting the microwires in form of closed-loop two-ply yarn we can create a torsional actuator. We achieved a revisable torsional stroke of 46°/mm with peak rotational speed of up to 10,000 rpm. We measured a gravimetric torque of up to 28.5 N•m/kg which is higher than the 3 - 6 N•m/kg for direct-drive commercial electric motors. These remarkable performance results are comparable to those of guest-infiltrated carbon nanotube twisted yarns.

  1. Modified teleparallel gravity with higher-derivative torsion terms

    NASA Astrophysics Data System (ADS)

    Otalora, Giovanni; Saridakis, Emmanuel N.

    2016-10-01

    We construct F (T ,(∇T) 2,□T ) gravitational modifications, which are novel classes of modified theories arising from higher-derivative torsional terms in the action and are different than their curvature analogue. Applying them in a cosmological framework, we obtain an effective dark energy sector comprised of the novel torsional contributions. We perform a detailed dynamical analysis for two specific examples, extracting the stable late-time solutions and calculating the corresponding observables. We show that the thermal history of the Universe can be reproduced, and it can result in a dark-energy-dominated, accelerating universe, where the dark-energy equation-of-state parameter lies in the quintessence regime, or may exhibit the phantom-divide crossing during the cosmological evolution. Finally, the scale factor behaves asymptotically, either as a power law or as an exponential, in agreement with observations.

  2. 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.

  3. Exact solutions in 3D gravity with torsion

    NASA Astrophysics Data System (ADS)

    González, P. A.; Vásquez, Yerko

    2011-08-01

    We study the three-dimensional gravity with torsion given by the Mielke-Baekler (MB) model coupled to gravitational Chern-Simons term, and that possess electric charge described by Maxwell-Chern-Simons electrodynamics. We find and discuss this theory's charged black holes solutions and uncharged solutions. We find that for vanishing torsion our solutions by means of a coordinate transformation can be written as three-dimensional Chern-Simons black holes. We also discuss a special case of this theory, Topologically Massive Gravity (TMG) at chiral point, and we show that the logarithmic solution of TMG is also a solution of the MB model at a fixed point in the space of parameters. Furthermore, we show that our solutions generalize Gödel type solutions in a particular case. Also, we recover BTZ black hole in Riemann-Cartan spacetime for vanishing charge.

  4. The Ground and First Excited Torsional States of Acetic Acid.

    PubMed

    Ilyushin, V. V.; Alekseev, E. A.; Dyubko, S. F.; Podnos, S. V.; Kleiner, I.; Margulès, L.; Wlodarczak, G.; Demaison, J.; Cosléou, J.; Maté, B.; Karyakin, E. N.; Golubiatnikov, G. Yu.; Fraser, G. T.; Suenram, R. D.; Hougen, J. T.

    2001-02-01

    A global fit of microwave and millimeter-wave rotational transitions in the ground and first excited torsional states (v(t) = 0 and 1) of acetic acid (CH(3)COOH) is reported, which combines older measurements from the literature with new measurements from Kharkov, Lille, and NIST. The fit uses a model developed initially for acetaldehyde and methanol-type internal rotor molecules. It requires 34 parameters to achieve a unitless weighted standard deviation of 0.84 for a total of 2518 data and includes A- and E-species transitions with J torsional interval is available. Copyright 2001 Academic Press.

  5. DNA-DNA interaction beyond the ground state

    NASA Astrophysics Data System (ADS)

    Lee, D. J.; Wynveen, A.; Kornyshev, A. A.

    2004-11-01

    The electrostatic interaction potential between DNA duplexes in solution is a basis for the statistical mechanics of columnar DNA assemblies. It may also play an important role in recombination of homologous genes. We develop a theory of this interaction that includes thermal torsional fluctuations of DNA using field-theoretical methods and Monte Carlo simulations. The theory extends and rationalizes the earlier suggested variational approach which was developed in the context of a ground state theory of interaction of nonhomologous duplexes. It shows that the heuristic variational theory is equivalent to the Hartree self-consistent field approximation. By comparison of the Hartree approximation with an exact solution based on the QM analogy of path integrals, as well as Monte Carlo simulations, we show that this easily analytically-tractable approximation works very well in most cases. Thermal fluctuations do not remove the ability of DNA molecules to attract each other at favorable azimuthal conformations, neither do they wash out the possibility of electrostatic “snap-shot” recognition of homologous sequences, considered earlier on the basis of ground state calculations. At short distances DNA molecules undergo a “torsional alignment transition,” which is first order for nonhomologous DNA and weaker order for homologous sequences.

  6. DNA-DNA interaction beyond the ground state.

    PubMed

    Lee, D J; Wynveen, A; Kornyshev, A A

    2004-11-01

    The electrostatic interaction potential between DNA duplexes in solution is a basis for the statistical mechanics of columnar DNA assemblies. It may also play an important role in recombination of homologous genes. We develop a theory of this interaction that includes thermal torsional fluctuations of DNA using field-theoretical methods and Monte Carlo simulations. The theory extends and rationalizes the earlier suggested variational approach which was developed in the context of a ground state theory of interaction of nonhomologous duplexes. It shows that the heuristic variational theory is equivalent to the Hartree self-consistent field approximation. By comparison of the Hartree approximation with an exact solution based on the QM analogy of path integrals, as well as Monte Carlo simulations, we show that this easily analytically-tractable approximation works very well in most cases. Thermal fluctuations do not remove the ability of DNA molecules to attract each other at favorable azimuthal conformations, neither do they wash out the possibility of electrostatic "snap-shot" recognition of homologous sequences, considered earlier on the basis of ground state calculations. At short distances DNA molecules undergo a "torsional alignment transition," which is first order for nonhomologous DNA and weaker order for homologous sequences.

  7. [Uterine torsion in cattle - frequency, clinical symptoms and theories about the pathogenesis].

    PubMed

    Erteld, E; Wehrend, A; Goericke-Pesch, S

    2012-01-01

    Aim of the present study was to summarize the available literature about the incidence, frequency, clinical symptoms and ideas as to the pathogenesis of uterine torsion in the cow. Analysis of the literature using electronic libraries (Pub Med, Medline), German veterinary medicine journals and obstetrical textbooks. Uterine torsion is a very important maternal reason for dystocia as most cases occur during parturition. The post-cervical torsion (combined uterine and vaginal torsion, Torsio uteri and vaginae) is more commonly diagnosed than an intra-cervical or pre-cervical torsion. Torsions to the left occur more frequently than to the right. Clinical symptoms clearly vary depending on the degree of torsion. The frequency in relation to all parturitions is described as between 0.5 and 1%, whereas the percentage of uterine torsions presented to the veterinarian as a reason for dystocia varies between 2.7 and 65%. The pathogenesis of uterine torsion remains unclear; however, general agreement exists that the cow is predisposed to uterine torsion due to its anatomy. It appears that the Brown Swiss is more often affected than other cattle breeds.

  8. Behavior of supercoiled DNA.

    PubMed Central

    Strick, T R; Allemand, J F; Bensimon, D; Croquette, V

    1998-01-01

    We study DNA supercoiling in a quantitative fashion by micromanipulating single linear DNA molecules with a magnetic field gradient. By anchoring one end of the DNA to multiple sites on a magnetic bead and the other end to multiple sites on a glass surface, we were able to exert torsional control on the DNA. A rotating magnetic field was used to induce rotation of the magnetic bead, and reversibly over- and underwind the molecule. The magnetic field was also used to increase or decrease the stretching force exerted by the magnetic bead on the DNA. The molecule's degree of supercoiling could therefore be quantitatively controlled and monitored, and tethered-particle motion analysis allowed us to measure the stretching force acting on the DNA. Experimental results indicate that this is a very powerful technique for measuring forces at the picoscale. We studied the effect of stretching forces ranging from 0.01 pN to 100 pN on supercoiled DNA (-0.1 < sigma < 0.2) in a variety of ionic conditions. Other effects, such as stretching-relaxing hysteresis and the braiding of two DNA molecules, are discussed. PMID:9545060

  9. 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.

  10. Stability of Thin-Walled Tubes Under Torsion

    NASA Technical Reports Server (NTRS)

    Donnell, L H

    1935-01-01

    In this report a theoretical solution is developed for the torsion on a round thin-walled tube for which the walls become unstable. The results of this theory are given by a few simple formulas and curves which cover all cases. The differential equations of equilibrium are derived in a simpler form than previously found, it being shown that many items can be neglected.

  11. Testicular conditions in athletes: torsion, tumors, and epididymitis.

    PubMed

    Sandella, Bradley; Hartmann, Brett; Berkson, David; Hong, Eugene

    2012-01-01

    Individuals involved in sports are at risk for sustaining various injuries. In addition to musculoskeletal complaints, male athletes are at risk of incurring testicular injuries. These issues can range from an acute emergency such as testicular torsion to indolent testicular tumors. In contrast, epididymitis can present in stages. Presentation and management of testicular complaints can vary depending on the condition. Physicians who provide medical care to athletes need to be competent in diagnosing and managing testicular injuries.

  12. 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).

  13. pp-waves with torsion and metric-affine gravity

    NASA Astrophysics Data System (ADS)

    Pasic, Vedad; Vassiliev, Dmitri

    2005-10-01

    A classical pp-wave is a four-dimensional Lorentzian spacetime which admits a nonvanishing parallel spinor field; here the connection is assumed to be Levi-Civita. We generalize this definition to metric compatible spacetimes with torsion and describe basic properties of such spacetimes. We use our generalized pp-waves for constructing new explicit vacuum solutions of quadratic metric-affine gravity.

  14. Upright Perception and Ocular Torsion Change Independently during Head Tilt

    PubMed Central

    Otero-Millan, Jorge; Kheradmand, Amir

    2016-01-01

    We maintain a stable perception of the visual world despite continuous movements of our eyes, head and body. Perception of upright is a key aspect of such orientation constancy. Here we investigated whether changes in upright perception during sustained head tilt were related to simultaneous changes in torsional position of the eyes. We used a subjective visual vertical (SVV) task, modified to track changes in upright perception over time, and a custom video method to measure ocular torsion simultaneously. We tested 12 subjects in upright position, during prolonged (~15 min) lateral head tilts of 20 degrees, and also after the head returned to upright position. While the head was tilted, SVV drifted in the same direction as the head tilt (left tilt: −5.4 ± 1.4° and right tilt: +2.2 ± 2.1°). After the head returned to upright position, there was an SVV aftereffect with respect to the pre-tilt baseline, which was also in the same direction as the head tilt (left tilt: −3.9 ± 0.6° and right tilt: +2.55 ± 1.0°). Neither the SVV drift nor the SVV aftereffect were correlated with the changes in ocular torsion. Using the Bayesian spatial-perception model we show that the pattern of SVV drift and aftereffect in our results could be explained by a drift and an adaptation in sensory inputs that encode head orientation. The fact that ocular torsion (mainly driven by the otoliths) could not account for the perceptual changes suggests that neck proprioception could be the primary source of drift in upright perception during head tilt, and subsequently the aftereffect in upright position. PMID:27909402

  15. 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

  16. Propagation and Reflection of Diffusionless Torsional Waves in a Sphere

    NASA Astrophysics Data System (ADS)

    Maffei, S.; Jackson, A.

    2015-12-01

    The magnetohydrodynamics of stars and planetary cores is usually dominated by the overwhelming importance of rotation compared to other forces. Under these conditions the fluid motions are characterized by a strong invariance along the rotation axis. In the presence of a background magnetic field, magnetohydrodynamic oscillations can be triggered. Among these, of particular interest are the torsional waves, azimuthal perturbations of the fluid that are axisymmetric and invariant along the vertical direction. Their periods depend solely on the intensity of the magnetic field component aligned with the radial direction of propagation. As the detection of the fundamental period could constrain the magnetic field intensity in the Earth's outer core there is a long history of attempted detection of torsional waves from geomagnetic data. There is however a fundamental lack of knowledge concerning the propagation and reflection properties of these waves, as observational studies suggests behaviors that are different from theoretical expectations. In particular, recent findings (Gillet et al., 2011) suggest the lack of reflection at the equator and at the rotation axis. Through numerical simulation and analytical techniques we analyze the temporal evolution of diffusionless torsional waves in spherical geometry, with particular attention on the reflection at the equator and the pseudo-reflection at the rotation axis. We develop a novel analytical solution to the torsional wave eigenvalue problem whose behavior at the boundaries helps us to illustrate the meaning of the boundary conditions. Furthermore we find that for any acceptable magnetic background field, reflections at both boundaries are allowed and we illustrate how the WKBJ approximation is an efficient tool for investigating them.

  17. Metatarsal torsion in monkeys, apes, humans and australopiths.

    PubMed

    Drapeau, Michelle S M; Harmon, Elizabeth H

    2013-01-01

    This paper presents an analysis of metatarsal torsion in apes, cercopithecoids and humans, compares australopiths with these species, and discusses their inferred foot morphology and function relative to prehensility, arboreality and the presence or absence of a longitudinal arch. Our results show that locomotor modes are reflected in metatarsal torsion values. Apes, which climb vertically with their foot inverted, have hallucal metatarsal heads that are turned toward the other toes and lateral toes that are inverted. Cercopithecoids, which tend to orient their feet in an axis more parallel to the line of motion, present signs of prehensility by having inverted 2nd metatarsals that oppose the hallux, while their two lateral-most metatarsals are strongly everted. Humans, with their rigid feet and longitudinal arches, have all toes that present their plantar surface toward the ground, resulting in hallucal and 2nd metatarsals that are relatively untwisted and the others that are strongly everted. Humans are different from all taxa only for the 2nd and 3rd metatarsal. It is hypothesized that the untwisted 2nd metatarsal reflects the lack of digit opposability of the medial foot and the strongly everted 3rd metatarsal reflects the longitudinal arch. Australopithecus afarensis was characterized by an everted lateral foot, the prerequisite for the development, but not necessarily an indicator, of a longitudinal arch. In Australopithecus africanus, torsion of fragmentary and complete 1st, 2nd, 3rd and 5th metatarsals suggest that the species did not have a foot with monkey- or ape-like prehensile capabilities and did not have a human-like longitudinal arch. In the Swartkrans remains, torsion is consistent with an unprehensile foot. The morphology of the fossils indicates that there was strong selection to orient the plantar surface of the toes facing the ground at the expense of a grasping foot and inversion ability. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Torsional Elastic Property Measurements of Selected Orthodontic Archwires.

    DTIC Science & Technology

    1987-01-01

    replacing gold in the middle of the century. If the orthodontist wished to have lighter forces over a greater range, he had two choices. First, he...length. The orthodontist was forced to make torque adjustments in small increments with a large, torsionally stiff, stainless steel wire. The concept...slot, respectively) were measured with strain gauges. The expected linear relationship between the torque magnitude and the activation angle was verified

  19. Microstructure and texture analyses of polycrystalline ice during hot torsion

    NASA Astrophysics Data System (ADS)

    Journaux, B.; Montagnat, M.; Gest, L.; Barou, F.; Chauve, T.

    2015-12-01

    Water ice Ih is a material with very high plastic anisotropy where deformation is mainly accommodated by dislocation glide on the (0001) plane. This anisotropy gives rise to strong strain incompatibilities between grains during deformation, and therefore impacts texture and microstructure evolution. Accurate understanding of ice mechanical properties is significant for several areas of research such as glaciology, planetary sciences, but also in geosciences and metallurgy as ice can be seen as a model material with easier experimental handling at near melting temperatures. In the present study, we used torsion experiments to study non-coaxial shear strain (γ), very common in natural environments, up to very high values of γ. Numerous studies determined microstructure and texture evolution in polycrystalline assemblage submitted to torsion (metallic alloys and geological materials) but a very limited number focused on polycrystalline ice. Full cylinders of randomly oriented polycrystalline ice (grain size ~ 1 mm) were placed in a torsion apparatus and deformed under ductile regime under constant imposed torque at 266K (0.97 Tf). Macroscopic shear was monitored using a LVDT device or a rotary encoder. Several torsion tests with maximal shear strain up to γmax = 1 were performed. Tangent and axial sections were analyzed ex-situ using Automatic Ice Texture Analyzer (AITA) and Electron BackScatter Diffraction (EBSD). We were able to confirm the previously observed bimodal preferred orientation of the basal slip plane. Macroscopic strain evolution γ(t) displays a weakening after γmax = 0.04 (ɛmax ≃ 2 %), due to the beginning of dynamic recrystallization (DRX) processes. EBSD data provide novel informations on the microstructure that suggest very efficient grain boundary migration processes. In particular, we were able to measure differences of intra-granular misorientations density between the two ODF maxima populations that can highlight the role of DRX

  20. 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

  1. Measuring orbital angular momentum of light with a torsion pendulum

    NASA Astrophysics Data System (ADS)

    Beijersbergen, Marco W.; Woerdman, J. P.

    2005-03-01

    We report experiments aimed at measuring the orbital angular momentum of light by means of a torsion pendulum, in the spirit of the classical spin angular momentum experiment by Beth (1936) but using present-day technology. Although our set-up has adequate sensitivity and resolution to measure orbital angular momentum of light, the systematic errors that are caused by the inherent asymmetry in the conversion of orbital angular moment remain a problem.

  2. Self-accelerating universe in modified gravity with dynamical torsion

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

    We consider a model belonging to the class of gravities with dynamical torsion. The model is free of ghosts and gradient instabilities about Minkowski and torsionless Einstein backgrounds. We find that at zero cosmological constant, the model admits a self-accelerating solution with a non-Riemannian connection. Small value of the effective cosmological constant is obtained at the expense of the hierarchy between the dimensionless couplings.

  3. Torsion of the greater omentum: treatment by laparoscopy.

    PubMed

    Sánchez, Javier; Rosado, Rafael; Ramírez, Diego; Medina, Pedro; Mezquita, Susana; Gallardo, Andrés

    2002-12-01

    Four new cases of necrosis of the omentum secondary to torsion are reported. We review the associated signs and symptoms, which are usually those of an acute inflammatory condition in the right lower quadrant (RLQ), very similar to acute appendicitis. Because of acute abdominal pain in the RLQ, along with an uncertain diagnosis, laparoscopic surgery was performed in these cases. Laparoscopy demonstrated the existence of the omental infarction and allowed for complete treatment of the condition without the need for laparotomy.

  4. Refinement of the Cornell et al. Nucleic Acids Force Field Based on Reference Quantum Chemical Calculations of Glycosidic Torsion Profiles

    PubMed Central

    2011-01-01

    We report a reparameterization of the glycosidic torsion χ of the Cornell et al. AMBER force field for RNA, χOL. The parameters remove destabilization of the anti region found in the ff99 force field and thus prevent formation of spurious ladder-like structural distortions in RNA simulations. They also improve the description of the syn region and the syn–anti balance as well as enhance MD simulations of various RNA structures. Although χOL can be combined with both ff99 and ff99bsc0, we recommend the latter. We do not recommend using χOL for B-DNA because it does not improve upon ff99bsc0 for canonical structures. However, it might be useful in simulations of DNA molecules containing syn nucleotides. Our parametrization is based on high-level QM calculations and differs from conventional parametrization approaches in that it incorporates some previously neglected solvation-related effects (which appear to be essential for obtaining correct anti/high-anti balance). Our χOL force field is compared with several previous glycosidic torsion parametrizations. PMID:21921995

  5. [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.

  6. 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.

  7. A torsion balance search for spin-coupled forces

    NASA Astrophysics Data System (ADS)

    Cramer, Claire E.

    Interactions that involve the coupling of a particle's intrinsic spin independent of its magnetic moment have been postulated, but never detected. This dissertation describes a precision search for spin-coupled forces that arise in the context of broken Lorentz and CPT symmetries, exotic particle exchange, non-commutative geometries, and torsion gravity. We used a torsion pendulum containing 9.8 x 1022 polarized electron spins to search for interactions between the pendulum's electrons and a vector field fixed in inertial space, a condensate of exotic particles defining a preferred frame in the universe, unpolarized matter in the laboratory's environment and the sun, and polarized matter in spin sources placed near to the pendulum. We have seen no evidence for these spin-coupled interactions. The measurements reported here constrain the energy required to flip an electron spin about directions fixed in inertial space to be ≲ 10-22 eV. We have used these constraints to place limits on preferred-frame effects and exotic boson exchange that are up to four orders of magnitude lower than the previous reported limits, and we present the first limits on dynamical effects associated with broken Lorentz symmetry. This dissertation describes the torsion balance apparatus used to perform these measurements, as well as the analysis of experimental data and systematic effects, and the corresponding results.

  8. 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.

  9. On the torsional loading of elastoplastic spheres in contact

    NASA Astrophysics Data System (ADS)

    Nadimi, Sadegh; Fonseca, Joana

    2017-06-01

    The mechanical interaction between two bodies involves normal loading in combination with tangential, torsional and rotational loading. This paper focuses on the torsional loading of two spherical bodies which leads to twisting moment. The theoretical approach for calculating twisting moment between two spherical bodies has been proposed by Lubkin [1]. Due to the complexity of the solution, this has been simplified by Deresiewicz for discrete element modelling [2]. Here, the application of a simplified model for elastoplastic spheres is verified using computational modelling. The single grain interaction is simulated in a combined finite discrete element domain. In this domain a grain can deform using a finite element formulation and can interact with other objects based on discrete element principles. For an elastoplastic model, the contact area is larger in comparison with the elastic model, under a given normal force. Therefore, the plastic twisting moment is stiffer. The results presented here are important for describing any granular system involving torsional loading of elastoplastic grains. In particular, recent research on the behaviour of soil has clearly shown the importance of plasticity on grain interaction and rearrangement.

  10. 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.

  11. X-linked recessive torsion dystonia in the Philippines.

    PubMed

    Kupke, K G; Lee, L V; Viterbo, G H; Arancillo, J; Donlon, T; Müller, U

    1990-06-01

    The occurrence of an X-linked form of torsion dystonia in the Philippines was demonstrated by the genetic and biochemical analysis of affected males and their relatives. Thirty-six affected males were ascertained in 21 families by clinical neurologic evaluation. The mean age-of-onset of dystonia was 37.9 years with a range from 12 to 52 years. Neurologic symptoms began focally and progressed to either segmental or generalized involvement in all cases. Generalized dystonia developed in 78% of the patients after a mean duration of 6.8 years from the onset of symptoms. A family history of dystonia was elicited in 17 of the 21 kindreds, accounting for a total of 64 males and one possibly affected female, distributed among 224 individuals in 33 sibships. In 18 of the 33 sibships, 2 or more brothers reportedly had dystonia. There were 12 kindreds with a history of multigenerational dystonia. In those, only males of maternal ancestry were affected, and in 7 of these families, maternal grandfathers reportedly had dystonia. There were no instances of male-to-male transmission. Cytogenetic analysis did not show any X chromosome abnormalities in 4 affected propositi. Several secondary causes of torsion dystonia were excluded, including Wilson disease, aminoacidopathies, organic acidurias, oligosaccharidoses, and chronic hexosaminidase A and B deficiency. These findings substantiate the existence of an X-linked recessive form of primary torsion dystonia.

  12. Design of a smart superstructure FBG torsion sensor

    NASA Astrophysics Data System (ADS)

    Miclos, Sorin; Savastru, Dan; Savastru, Roxana; Lancranjan, Ion I.

    2015-05-01

    The paper presents the results obtained in simulation of a Superstructure Fiber Bragg Grating (SFBG) torsion sensor. The SFBG sensor simulation points to an improved smart composite or metallic parts design to be operated under torsion loads in various applications. SFBG sensor simulation consists of correlating the fiber deformation under applied mechanical loads with the modified FBG characteristic reflection spectrum considering the polarization mode variations. The analyzed SFBG is developed by the selective deposition of on-fiber periodic metal thin films on regular FBGs. The torsion mechanical loads induced shifts in the characteristic reflection spectrum of Bragg wavelength and side bands are analyzed. For obtaining information about an optimal structure of SFBG sensor, simulation is performed for four commercially available photosensitive single mode silica optical fibers having different geometric and optical characteristics, mainly core and clad refractive index values. It is considered that, by using an UV writing technique, Brag gratings are induced into the simulated SFBG. Simulations are performed considering different geometric characteristics of the shaft used as mechanical mount of SFBG. The simulation results are in fairly good agreement with the experimental ones reported in literature.

  13. 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.

  14. 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. PMID:27621783

  15. Effects of High-Frequency Torsional Impacts on Rock Drilling

    NASA Astrophysics Data System (ADS)

    Zhu, Xiaohua; Tang, Liping; Tong, Hua

    2014-07-01

    High-frequency torsional impact drilling (HFTID) is a new technology which provides stable and efficient drilling. The goal of the present study is to investigate the effects of high-frequency torsional impacts on rock drilling. The impact parameters of the high-frequency torsional impact generator (HFTIG) are obtained by conducting a series of laboratory tests. The results of the tests reveal that the impact time decreases and the impact force increases with increasing impact frequency. The parameters are used as input for simulations of the rock crushing process, and a series of models for investigating the respective performance of HFTID and conventional drilling are developed. In addition, the Drucker-Prager criterion is used to describe the constitutive laws of the rock element, and the equivalent plastic strain criterion is adopted as the damage criterion. The models are run to simulate the dynamic rock crushing processes. The results of the simulations show that increase of the impact frequency results in a significant improvement in the rate of penetration (ROP), and a decrease in the life of the HFTIG. Considering the tool life and ROP, the optimum impact frequency of the HFTIG is 15 Hz. Finally, the performance of the HFTID technique is evaluated.

  16. Solar neutrinos, helicity effects and new affine gravity with torsion

    NASA Astrophysics Data System (ADS)

    Cirilo-Lombardo, Diego Julio

    2013-12-01

    New f(R, T) model of gravitation, introduced previously by the author, is considered. It is based on an affine geometrical construction in which the torsion is a dynamical field, the coupling is minimal and the theory is Lorentz invariant by construction. It was shown that the Dirac equation emerges from the same space time and acquires a modification (coupling-like) of the form γα j 1-d/d γ5hα , with hα the torsion axial vector, j a parameter of pure geometrical nature and d, the spacetime dimension. In the present work it is shown that this interaction produces a mechanism of spin (helicity) flipping, with its consequent weak symmetry violation. The cross section of this process is explicitly calculated and a logarithmic energy dependence (even at high energies) is found. This behavior is reminiscent of similar computations made by Hans Bethe in the context of neutrino astrophysics. These results are applied to the solar neutrino case and compared with similar results coming from a gravitational model with torsion of string theory type and within the standard model context respectively.

  17. 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.

  18. A Rare Emergency: Testicular Torsion in the Inguinal Canal

    PubMed Central

    Şener, Nevzat Can; Bas, Okan; Yesil, Suleyman; Zengin, Kursad; Imamoglu, Abdurrahim

    2015-01-01

    Objectives. To report our experience and present the largest series of testicular torsion cases in the inguinal canal. Material and Methods. The clinical data of 13 patients with testicular torsion in the inguinal canal treated between 2005 and 2013 were reviewed. Recorded patient age, whether the testes were palpable or not, side of the affected testes, the presence of hernia, ischemia time, and operation outcomes were assessed. Results. Patient age ranged from 8 to 70 months (29.15 ± 20.22). Mean ischemia time was 16.5 ± 21.3 hours. Accompanying inguinal hernia was present in 92% of the cases (12/13). Four of the thirteen patients (30.8%) were treated by orchiectomy because the necrosis was present after prolonged ischemia time. Nine patients (69.2%) were treated by single session orchidopexy. Conclusion. Torsion of testes in the inguinal canal is a rare disease, but with rapid diagnosis, affected testes can be salvaged, but the key factor is to keep this condition in mind. PMID:25654093

  19. Twisted ultrathin silicon nanowires: A possible torsion electromechanical nanodevice

    NASA Astrophysics Data System (ADS)

    Garcia, J. C.; Justo, J. F.

    2014-11-01

    Nanowires have been considered for a number of applications in nanometrology. In such a context, we have explored the possibility of using ultrathin twisted nanowires as torsion nanobalances to probe forces and torques at molecular level with high precision, a nanoscale system analogous to the Coulomb's torsion balance electrometer. In order to achieve this goal, we performed a first-principles investigation on the structural and electronic properties of twisted silicon nanowires, in their pristine and hydrogenated forms. The results indicated that wires with pentagonal and hexagonal cross-sections are the thinnest stable silicon nanostructures. Additionally, all wires followed a Hooke's law behavior for small twisting deformations. Hydrogenation leads to spontaneous twisting, but with angular spring constants considerably smaller than the ones for the respective pristine forms. We observed considerable changes on the nanowire electronic properties upon twisting, which allows to envision the possibility of correlating the torsional angular deformation with the nanowire electronic transport. This could ultimately allow a direct access to measurements on interatomic forces at molecular level.

  20. Diesel engine torsional vibration control coupling with speed control system

    NASA Astrophysics Data System (ADS)

    Guo, Yibin; Li, Wanyou; Yu, Shuwen; Han, Xiao; Yuan, Yunbo; Wang, Zhipeng; Ma, Xiuzhen

    2017-09-01

    The coupling problems between shafting torsional vibration and speed control system of diesel engine are very common. Neglecting the coupling problems sometimes lead to serious oscillation and vibration during the operation of engines. For example, during the propulsion shafting operation of a diesel engine, the oscillation of engine speed and the severe vibration of gear box occur which cause the engine is unable to operate. To find the cause of the malfunctions, a simulation model coupling the speed control system with the torsional vibration of deformable shafting is proposed and investigated. In the coupling model, the shafting is simplified to be a deformable one which consists of several inertias and shaft sections and with characteristics of torsional vibration. The results of instantaneous rotation speed from this proposed model agree with the test results very well and are successful in reflecting the real oscillation state of the engine operation. Furthermore, using the proposed model, the speed control parameters can be tuned up to predict the diesel engine a stable and safe running. The results from the tests on the diesel engine with a set of tuned control parameters are consistent with the simulation results very well.

  1. 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.

  2. Ocular torsion before and after 1 hour centrifugation.

    PubMed

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

    1996-01-01

    To assess a possible otolith contribution to effects observed following prolonged exposure to hypergravity, we used video oculography to measure ocular torsion during static and dynamic conditions of lateral body tilt (roll) before and after 1 h of centrifugation with a Gx-load of 3 G. Static tilt (from 0 to 57 degrees to either side) showed a 10% decrease in otolith-induced ocular torsion after centrifugation. This implies a reduced gain of the otolith function. The dynamic condition consisted of sinusoidal body roll (frequency 0.25 Hz, amplitude 45 degrees) about an earth horizontal and about an earth vertical axis (respectively, "with" and "without" otolith stimulation). Before centrifugation the gain of the slow component velocity (SCV) was significantly lower "with" otolith stimulation than "without" otolith stimulation. Apparently, the contribution of the otoliths counteracts the ocular torsion response generated by the semicircular canals. Therefore, the observed increase in SCV gain in the condition "with" otolith stimulation after centrifugation, seems in correspondence with the decreased otolith gain in the static condition.

  3. Novel technique for relieving anastomotic tension using halo-vest immobilization after tracheal sleeve resection.

    PubMed

    Imai, Kazuhiro; Minamiya, Yoshihiro; Saito, Hajime; Miyakoshi, Naohisa; Hongo, Michio; Kasukawa, Yuji; Ishikawa, Yoshinori; Motoyama, Satoru; Sato, Yusuke; Shimada, Yoichi; Ogawa, Jun-ichi

    2013-07-01

    We describe a novel technique of using halo-vest-enforced immobilization to relieve anastomotic tension after tracheal sleeve resection. Immediately after the tracheal sleeve resection, four halo titanium pins were inserted in the skulls of the patients to secure the halo-vest. All patients fitted with halo-vests were able to eat and drink and their clinical course was good. Bronchoscopy confirmed the absence of anastomotic leaks and stenoses, and there were no complications associated with the halo-vest. We believe that ensuring neck flexion using a halo-vest after tracheal sleeve resection is an excellent way of relieving anastomotic tension that would predispose the wound to dehiscence.

  4. 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.

  5. 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

  6. 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.

  7. Molecular dynamics study of the torsional vibration characteristics of boron-nitride nanotubes

    NASA Astrophysics Data System (ADS)

    Ansari, R.; Ajori, S.

    2014-08-01

    In recent years, synthesizing inorganic nanostructures such as boron nitride nanotubes (BNNTs) has led to extensive studies on their exceptional properties. In this study, the torsional vibration behavior of boron-nitride nanotubes (BNNTs) is explored on the basis of molecular dynamics (MD) simulation. The results show that the torsional frequency is sensitive to geometrical parameters such as length and boundary conditions. The axial vibration is found to be induced by torsional vibration of nanotubes which can cause instability in the nanostructure. It is also observed that the torsional frequency of BNNTs is higher than that of their carbon counterpart. Moreover, the shear modulus is predicted by incorporating MD simulation numerical results into torsional vibration frequency obtained through continuum-based model of tubes. Finally, it is seen that the torsional frequency of double-walled boron-nitride nanotubes (DWBNNTs) is between the frequencies of their constituent inner and outer tubes.

  8. Excitation of torsional modes of proteins via collisional energy transfer: A quantum dynamical approach

    NASA Astrophysics Data System (ADS)

    Clary, David C.; Meijer, Anthony J. H. M.

    2002-06-01

    Quantum dynamical calculations have been carried out on the excitation of the torsional vibrations of a protein by collision with a solvent molecule. This energy transfer process represents the first step in the unfolding of the protein. The method developed for this purpose is the torsional close coupling, infinite order sudden approximation. Both time-independent and time dependent methods are used to solve the scattering problem and individual excitation of all the torsional modes of the protein is treated. The method is applied to the excitation of the HIV protein gp41 colliding with a water molecule. This protein has 1101 atoms, 56 amino acids, and 452 torsional modes. A major mode-selective effect is found in the computations: it is much easier to excite backbone torsions than sidechain torsions in the protein. In addition, resonances arise in the collisional process and these complexes involve temporary trapping of the water molecule inside the pockets of the protein.

  9. Torsion sensors of high sensitivity and wide dynamic range based on a graphene woven structure.

    PubMed

    Yang, Tingting; Wang, Yan; Li, Xinming; Zhang, Yangyang; Li, Xiao; Wang, Kunlin; Wu, Dehai; Jin, Hu; Li, Zhihong; Zhu, Hongwei

    2014-11-07

    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.

  10. Ultrasonographic identification of nerve pathology in neuralgic amyotrophy: Enlargement, constriction, fascicular entwinement, and torsion.

    PubMed

    Arányi, Zsuzsanna; Csillik, Anita; Dévay, Katalin; Rosero, Maja; Barsi, Péter; Böhm, Josef; Schelle, Thomas

    2015-10-01

    The aim of this study was to characterize the ultrasonographic findings on nerves in neuralgic amyotrophy. Fourteen patients with neuralgic amyotrophy were examined using high-resolution ultrasound. Four types of abnormalities were found: (1) focal or diffuse nerve/fascicle enlargement (57%); (2) incomplete nerve constriction (36%); (3) complete nerve constriction with torsion (50%; hourglass-like appearance); and (4) fascicular entwinement (28%). Torsions were confirmed intraoperatively and were seen on the radial nerve in 85% of patients. A significant correlation was found between no spontaneous recovery of nerve function and constriction/torsion/fascicular entwinement (P = 0.007). Ultrasonographic nerve pathology in neuralgic amyotrophy varies in order of severity from nerve enlargement to constriction to nerve torsion, with treatment ranging from conservative to surgical. We postulate that the constriction caused by inflammation is the precursor of torsion and that development of nerve torsion is facilitated by the rotational movements of limbs. © 2015 Wiley Periodicals, Inc.

  11. Evidence that gastropod torsion is driven by asymmetric cell proliferation activated by TGF-beta signalling.

    PubMed

    Kurita, Yoshihisa; Wada, Hiroshi

    2011-10-23

    Gastropods are characterized by their asymmetric bodyplan, which develops through a unique ontogenetic process called 'torsion'. Despite several intensive studies, the driving force of torsion remains to be determined. Although torsion was traditionally believed to be driven by contraction of the retractor muscle connecting the foot and the shell, some recent reports cast doubt on that idea. Here, we report that torsion is accompanied by left-right asymmetric cell proliferation in the mantle epithelium in the limpet Nipponacmea fuscoviridis. Furthermore, we found that pharmacological inhibition of the transforming growth factor-β (TGF-β) signalling pathway, including that of Nodal, blocked torsion. We confirmed that the blocking was brought about through failure of the activation of cell proliferation in the right-hand side of the mantle epithelium, while the retractor muscle apparently developed normally. These results suggest that limpet torsion is driven by left-right asymmetric cell proliferation in the mantle epithelium, induced by the TGF-β pathway.

  12. 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.

  13. Deformation and failure mechanisms of braided composite tubes in compression and torsion

    SciTech Connect

    Harte, A.M.; Fleck, N.A.

    2000-04-03

    The deformation and fracture behavior of glass fibre-epoxy braided circular tubes is examined experimentally and theoretically for the loading cases of compression, torsion, and combined tension-torsion and compression-torsion. Failure maps are produced for compression and for torsion to summarize the effect of braid microstructure upon failure mode and upon the mechanical properties of the braid, including yield strength, modulus, strain to failure and energy absorption. In compression, two competing mechanisms are observed: diamond shaped buckling of the tube and fibre microbuckling. In torsion and in combined compression-torsion, the tubes fail by fibre microbuckling. The initiation and propagation stresses for diamond shaped buckling, and the critical stress for fibre microbuckling are successfully predicted using simple micromechanical models. Drawing upon the available experimental data, yield surfaces are constructed for in-plane loading of the braid, and a comprehensive mechanism map is constructed to illustrate the dependence of failure mode upon braid geometry and loading direction.

  14. 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.

  15. Torsion Tests of 24S-T Aluminum-alloy Noncircular Bar and Tubing

    NASA Technical Reports Server (NTRS)

    Moore, R L; Paul, D A

    1943-01-01

    Tests of 24S-T aluminum alloy have been made to determine the yield and ultimate strengths in torsion of noncircular bar and tubing. An approximate basis for predicting these torsional strength characteristics has been indicated. The results show that the torsional stiffness and maximum shearing stresses within the elastic range may be computed quite closely by means of existing formulas based on mathematical analysis and the membrane analogy.

  16. 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.

  17. 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.

  18. 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.

  19. Inferior Vena Cava Torsion and Stenosis Complicated by Compressive Pericaval Regional Ascites following Orthotopic Liver Transplantation

    PubMed Central

    Gilroy, Richard; Johnson, Philip

    2013-01-01

    Inferior vena cava (IVC) stenosis and torsion are well-described rare complications following orthotopic liver transplantation (OLT). We present a case of inferior vena cava intermittent torsion and stenosis complicated by compressive regional ascites. To the best of our knowledge, this is the second case of post-OLT regional ascites related compressive IVC stenosis reported and the first reported case of torsion complicated by regional ascites compression. PMID:24386585

  20. Application of Torsional Vibration Measurement to Shaft Crack Monitoring in Power Plants

    DTIC Science & Technology

    2001-04-05

    speed [8]. However, the shaft lateral vibration data exhibited none of the signs of whirl. In addition, the three closely spaced subsynchronous peaks were...these subsynchronous frequencies corresponds to the "rigid body" torsional mode on torsional springs corresponding to the bearing film stiffness in shear...5 -Run7 ..... Run 9 . .... R un ’OS- Rn J11 1.E-03 I.E-0, 0 2 3 4 5 Frequency (Hz) Figure 6: Subsynchronous torsional spectrum for hydro unit shaft

  1. 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.

  2. 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.

  3. Spontaneous formation of non-uniform double helices for elastic rods under torsion

    NASA Astrophysics Data System (ADS)

    Li, Hongyuan; Zhao, Shumin; Xia, Minggang; He, Siyu; Yang, Qifan; Yan, Yuming; Zhao, Hanqiao

    2017-02-01

    The spontaneous formation of double helices for filaments under torsion is common and significant. For example, the research on the supercoiling of DNA is helpful for understanding the replication and transcription of DNA. Similar double helices can appear in carbon nanotube yarns, cables, telephone wires and so forth. We noticed that non-uniform double helices can be produced due to the surface friction induced by the self-contact. Therefore an ideal model was presented to investigate the formation of double helices for elastic rods under torque. A general equilibrium condition which is valid for both the smooth surface and the rough surface situations is derived by using the variational method. By adding further constraints, the smooth and rough surface situations are investigated in detail respectively. Additionally, the model showed that the specific process of how to twist and slack the rod can determine the surface friction and hence influence the configuration of the double helix formed by rods with rough surfaces. Based on this principle, a method of manufacturing double helices with designed configurations was proposed and demonstrated. Finally, experiments were performed to verify the model and the results agreed well with the theory.

  4. An investigation on the behaviour and stiffness of reinforced concrete slabs subjected to torsion

    NASA Astrophysics Data System (ADS)

    Nguyen, M. C. T.; Pham, P. T.

    2017-01-01

    This paper presents an investigation on RC slab under torsion, by both experiment and finite element analysis. The torsion tests were done on three similar square RC slabs with dimensions of 1900×1900×150 mm. The behaviour of slabs at pre-cracking and post-cracking of concrete phases were investigated, via Load-displacement, twisting moment-curvature relationships, and torsional stiffness of slabs. The experimental results are compared with the FEA and the results in literatures. The torsional stiffness of slab at the phase of concrete cracked and steel yield is about 1/25 of the stiffness at the pre-cracking phase.

  5. Detection of testicular torsion by magnetic resonance imaging in a rat model.

    PubMed

    Landa, H M; Gylys-Morin, V; Mattery, R F; Hajek, P; Krous, H F; Kaplan, G W; Packer, M G

    1988-11-01

    Testicular torsion is one of the most common pediatric urological emergencies. Incorrect or delayed diagnosis contributes significantly to morbidity. We previously have shown that magnetic resonance displays scrotal contents with great detail using hydrogen concentration weighted and T2 weighted images. Sprague-Dawley rats underwent either unilateral 720-degree testicular torsion or a sham procedure. Magnetic resonance images were obtained at intervals with a 3 or 5-inch surface coil. Scans after surgical torsion showed a characteristic spiral distortion of the fascial planes of the spermatic cord, not seen in the sham animals, as well as a decrease in testicular size with prolonged torsion.

  6. 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.

  7. 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…

  8. Effects of herbal medicine Sijunzi decoction on rabbits after relieving intestinal obstruction.

    PubMed

    Li, L; Zou, C; Zhou, Z; Yu, X

    2017-09-21

    Intestinal obstruction leads to blockage of the movement of intestinal contents. After relieving the obstruction, patients might still suffer with compromised immune function and nutritional deficiency. This study aimed to evaluate the effects of Sijunzi decoction on restoring the immune function and nutritional status after relieving the obstruction. Experimental rabbits (2.5±0.2 kg) were randomly divided into normal control group, 2-day intestinal obstruction group, 2-day natural recovery group, 4-day natural recovery group, 2-day treated group, and 4-day treated group. Sijunzi decoction was given twice a day to the treated groups. The concentration of markers was analyzed to evaluate the immune function and nutritional status. The concentration of interleukin-2, immunoglobulins and complement components of the treated groups were significantly higher than the natural recovery group (P<0.05). The levels of CD4+ and CD4+/CD8+ increased then decreased in the treated groups. The levels of tumor necrosis factor-α and CD8+ were significantly lower than the natural recovery group. The level of total protein in the treated groups also increased then decreased after relieving the obstruction. The levels of albumin, prealbumin and insulin-like growth factor-1 were significantly higher in the treated groups than in the natural recovery group (P<0.05). Transferrin level in the treated groups was significantly higher than the obstruction group (P<0.05). Sijunzi decoction can lessen the inflammatory response and improve the nutrition absorption after relieving the obstruction.

  9. UV photolysis for relieved inhibition of sulfadiazine (SD) to biomass growth.

    PubMed

    Pan, Shihui; Yan, Ning; Zhang, Yongming; Rittmann, Bruce E

    2015-05-01

    UV photolysis was used to relieve inhibition of biomass growth by sulfadiazine (SD), a broad-spectrum anti-microbial. To investigate the effects of SD on biomass growth, three substrates-glucose alone (G), glucose plus sulfadiazine (G+SD), and glucose plus photolyzed SD (G+PSD)-were used to culture the bacteria acclimated to glucose. The biomass was strongly inhibited when SD was added into the glucose solution, but inhibition was relieved to a significant degree when the SD was treated with UV irradiation as a pretreatment. The biomass growth kinetics were described well by the Monod model when glucose was used as a substrate alone, but the kinetics followed a hybrid Aiba model for non-competitive inhibition when SD was added to the solution. When photolyzed SD was added to glucose solution to replace original SD, the growth still followed Aiba inhibition, but inhibition was significantly relieved: the maximum specific growth rate (μ max) increased by 17 %, and the Aiba inhibition concentration increased by 60 %. Aniline, a major product of UV photolysis, supported the growth of the glucose-biodegrading bacteria. Thus, UV photolysis of SD significantly relieved inhibition by lowering the SD concentration and by generating a biodegradable product.

  10. Simultaneous Determination of Aspirin, Salicylamide, and Caffeine in Pain Relievers by Target Factor Analysis

    NASA Astrophysics Data System (ADS)

    Msimanga, Huggins Z.; Charles, Melissa J.; Martin, Nea W.

    1997-09-01

    A factor analysis-based experiment for the undergraduate instrumental analysis labs is reported. Target factor analysis (TFA) is investigated as an option to the use of high-performance liquid chromatography (HPLC) in the analysis of a pain reliever sample containing aspirin, caffeine, and salicylamide.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  12. 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…

  13. 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...

  14. 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 to...

  15. 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

  16. Volar denervation and osteophyte resection to relieve volar CMC joint pain

    PubMed Central

    Dellon, A. Lee

    2017-01-01

    Abstract At mean 125.6 months, pain was reduced from mean of 8.7 to 0.67, p < .001. Each of three patients, two of whom were musicians, returned to full professional ability. It is concluded that volar CMC joint denervation is a useful procedure, preserving joint function and relieving pain long-term. PMID:28243611

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

    PubMed

    Lee, Garam

    2015-12-01

    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. 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. 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. From the results, the importance of a balanced understanding of emotional labor for establishing effective policies for emotional laborer protection is stressed.

  18. Non-prescribed use of pain relievers among adolescents in the United States.

    PubMed

    Wu, Li-Tzy; Pilowsky, Daniel J; Patkar, Ashwin A

    2008-04-01

    We examined gender-specific prevalences, patterns, and correlates of non-prescribed use of pain relievers - mainly opioids - in a representative sample of American adolescents (N=18,678). Data were drawn from the public use data file of the 2005 U.S. National Survey on Drug Use and Health, a survey of non-institutionalized American household residents. The patterns of non-prescribed use of prescription pain relievers were examined, and logistic regression procedures were conducted to identify correlates of non-prescribed use. Approximately one in 10 adolescents aged 12-17 years reported non-prescribed use of pain relievers in their lifetime (9.3% in males and 10.3% in females). The mean age of first non-prescribed use was 13.3 years, which was similar to the mean age of first use of alcohol and marijuana but older than the age of first inhalant use. Among all non-prescribed users, 52% reported having used hydrocodone products (Vicodin, Lortab, Lorcet, and Lorcet Plus, and hydrocodone), 50% had used propoxyphene (Darvocet or Darvon) or codeine (Tylenol with codeine), and 24% had used oxycodone products (OxyContin, Percocet, Percodan, and Tylox). Approximately one quarter (26%) of all non-prescribed users had never used other non-prescribed or illicit drugs. There were gender variations in correlates of non-prescribed use. Use of non-prescribed pain relievers occurs early in adolescence. Research is needed to understand whether early use of non-prescribed pain relievers is related to later drug use.

  19. Focal point analysis of torsional isomers of acrylic acid

    NASA Astrophysics Data System (ADS)

    Alev Çiftçioğlu, Gökçen; Trindle, Carl; Yavuz, Ilhan

    2010-10-01

    The thermochemistry of acrylic acid has presented challenges owing to its high reactivity, tendency to dimerize in the gas phase, and the existence of two very nearly equal energy conformational isomers. Well-tested thermochemical schemes including G2, G3, G4, and CBS-QB3 agree in the prediction that the s-cis syn structure is the most stable of the torsional isomers, with the s-cis anti form lying 3 kJ mol-1 or less higher in energy. Microwave spectra suggest a value of 0.63 kJ mol-1. The energy barrier between these forms is in the neighbourhood of 25 kJ mol-1 according to a MP2/cc-pVDZ calculation. We present estimates of the relative energies of all four torsional isomers and the rotational barrier based on a variant of the Focal Point Analysis developed by Császár and co-workers. These calculations, extending to the CCSD(T)/cc-pV5Z level, predict that the s-cis anti torsional isomer is the most stable form, in contrast to prior estimates. The s-cis syn form lies about 2.9 kJ mol-1 higher, while the s-trans syn and anti forms lie at about 21.7 and 23.3 kJ mol-1, respectively. We estimate the rotational barrier between the s-cis trans and s-cis anti structures to be about 23.9 kJ mol-1. Error ranges derived from the fit to extrapolation forms suggest that our estimates have an uncertainty of about 0.1 kJ mol-1.

  20. Mapping conformational dynamics of proteins using torsional dynamics simulations.

    PubMed

    Gangupomu, Vamshi K; Wagner, Jeffrey R; Park, In-Hee; Jain, Abhinandan; Vaidehi, Nagarajan

    2013-05-07

    All-atom molecular dynamics simulations are widely used to study the flexibility of protein conformations. However, enhanced sampling techniques are required for simulating protein dynamics that occur on the millisecond timescale. In this work, we show that torsional molecular dynamics simulations enhance protein conformational sampling by performing conformational search in the low-frequency torsional degrees of freedom. In this article, we use our recently developed torsional-dynamics method called Generalized Newton-Euler Inverse Mass Operator (GNEIMO) to study the conformational dynamics of four proteins. We investigate the use of the GNEIMO method in simulations of the conformationally flexible proteins fasciculin and calmodulin, as well as the less flexible crambin and bovine pancreatic trypsin inhibitor. For the latter two proteins, the GNEIMO simulations with an implicit-solvent model reproduced the average protein structural fluctuations and sample conformations similar to those from Cartesian simulations with explicit solvent. The application of GNEIMO with replica exchange to the study of fasciculin conformational dynamics produced sampling of two of this protein's experimentally established conformational substates. Conformational transition of calmodulin from the Ca(2+)-bound to the Ca(2+)-free conformation occurred readily with GNEIMO simulations. Moreover, the GNEIMO method generated an ensemble of conformations that satisfy about half of both short- and long-range interresidue distances obtained from NMR structures of holo to apo transitions in calmodulin. Although unconstrained all-atom Cartesian simulations have failed to sample transitions between the substates of fasciculin and calmodulin, GNEIMO simulations show the transitions in both systems. The relatively short simulation times required to capture these long-timescale conformational dynamics indicate that GNEIMO is a promising molecular-dynamics technique for studying domain motion in

  1. Mapping Conformational Dynamics of Proteins Using Torsional Dynamics Simulations

    PubMed Central

    Gangupomu, Vamshi K.; Wagner, Jeffrey R.; Park, In-Hee; Jain, Abhinandan; Vaidehi, Nagarajan

    2013-01-01

    All-atom molecular dynamics simulations are widely used to study the flexibility of protein conformations. However, enhanced sampling techniques are required for simulating protein dynamics that occur on the millisecond timescale. In this work, we show that torsional molecular dynamics simulations enhance protein conformational sampling by performing conformational search in the low-frequency torsional degrees of freedom. In this article, we use our recently developed torsional-dynamics method called Generalized Newton-Euler Inverse Mass Operator (GNEIMO) to study the conformational dynamics of four proteins. We investigate the use of the GNEIMO method in simulations of the conformationally flexible proteins fasciculin and calmodulin, as well as the less flexible crambin and bovine pancreatic trypsin inhibitor. For the latter two proteins, the GNEIMO simulations with an implicit-solvent model reproduced the average protein structural fluctuations and sample conformations similar to those from Cartesian simulations with explicit solvent. The application of GNEIMO with replica exchange to the study of fasciculin conformational dynamics produced sampling of two of this protein’s experimentally established conformational substates. Conformational transition of calmodulin from the Ca2+-bound to the Ca2+-free conformation occurred readily with GNEIMO simulations. Moreover, the GNEIMO method generated an ensemble of conformations that satisfy about half of both short- and long-range interresidue distances obtained from NMR structures of holo to apo transitions in calmodulin. Although unconstrained all-atom Cartesian simulations have failed to sample transitions between the substates of fasciculin and calmodulin, GNEIMO simulations show the transitions in both systems. The relatively short simulation times required to capture these long-timescale conformational dynamics indicate that GNEIMO is a promising molecular-dynamics technique for studying domain motion in

  2. The study about torsional vibration charateristics and its optimization of vehicle transmission system

    NASA Astrophysics Data System (ADS)

    Huang, Yuxin; Xin, Qinkun; Yin, Huabing

    2010-06-01

    The torsional vibration of vehicle transmission system is heavily concerned with the increase of vehicle speed. The whole powertrain system has to be matched according to the torsional vibration characteristics, especially in developing a new vehicle. The selection of proper elastic coupling has to be made for the torsional vibration match and some frequencies have to be moved out of engine's range . Thus the torsional vibration model of powertrain needs to be built. In the paper a new torsional vibration model is built, which is programmed in the form of a platform. The whole powertrain system torsional vibration model of a vehicle is built firstly with consideration of gear mesh stiffness and engine's excitation in it. The free torsional vibration mode analysis is made and the resonant torques of each lumped inertia in the transmission system are obtained. Secondly the forced vibration of transmission system with the engine's excitation is made and the dynamic torques of each lumped inertias are obtained. Thirdly the process for the torsional vibration analysis is integrated into the optimization process and the selection of elastic coupling for the transmission system is made according the optimization and match results. Fourthly in order to modify the design parameters in the structural design, the sensitivities of inertia and torsional stiffness with reference to eigenvalues are obtained. At last the evaluations of analysis results are made and some suggestions for structural modification for engineers are presented. According to the above study, the conclusion can be made that the new torsional modelling method, the elastic coupling selection method and integration optimization method in the paper are practical and reliabl and these methods play very important roles in torsional vibration analyzing, match and optimization of vehicle transmission system.

  3. 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

  4. 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

  5. In vitro biomechanical study of femoral torsion disorders: effect on femoro-tibial kinematics.

    PubMed

    Sobczak, S; Dugailly, P-M; Baillon, B; Lefevre, P; Rooze, M; Salvia, P; Feipel, V

    2012-12-01

    Gonarthrosis is a degenerative disease mainly found in elderly persons. Frontal plane deviations are known to induce lateral and medial gonarthrosis. Nevertheless, patients suffer from gonarthrosis without frontal deviations. Lower limb torsions disorders have been considered as a factor inducing lateral and medial gonarthrosis. This paper reports an in vitro study aiming at quantifying the relationships between experimental femoral torsion disorders and femoro-tibial kinematics. Five fresh-frozen lower limbs were used. Specimens were fixed on an experimental jig and muscles were loaded. A six-degree-of-freedom Instrumented Spatial Linkage was used to measure femoro-tibial kinematics. Experimental femoral osteotomies were performed to simulate various degrees of medial and lateral torsion. Internal tibial rotation, abduction/adduction and proximo-distal, medio-lateral and antero-posterior translations were measured during knee flexion. Internal tibial rotation and abduction/adduction were significantly influenced (P<0.001) by femoral torsion disorder conditions. Medial femoral torsion increased tibial adduction and decreased internal rotation during knee flexion. Opposite changes were observed during lateral femoral torsion. Concerning translations, medial femoral torsion induced a significant (P<0.05) decrease of medial translation and inversely for lateral femoral torsion. No interactions between femoral torsion disorders and range of motion were observed. Our results showed that medial and lateral femoral torsion disorders induced alterations of femoro-tibial kinematics when applied in normally aligned lower limbs. These results highlight a potential clinical relevance of the effect of femoral torsion alterations on knee kinematics that may be related to the development of long-term knee disease. Copyright © 2012 Elsevier Ltd. All rights reserved.

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

    PubMed Central

    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

  7. Femoral torsion and neck-shaft angles in cerebral palsy.

    PubMed

    Laplaza, F J; Root, L; Tassanawipas, A; Glasser, D B

    1993-01-01

    Excessive femoral and coxa valga have been reported to be major contributors leading to hip dislocation in patients with cerebral palsy (CP). Femoral torsion angle (FT) and neck-shaft angle (NSA) were measured by the radiographic technique described by Rippstein and Müller in 157 patients with CP (289 hips). Factors associated with the degree of FT and NSA were evaluated. The researchers explored the correlation between the two angles and hip pathology. A large database of measurements was constructed. Our findings suggest that age and ambulatory status are the main factors correlated with FT and NSA.

  8. 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.

  9. Numerical Simulation of Gleeble Torsion Testing of HSLA-65 Steel

    DTIC Science & Technology

    2008-04-01

    Simulation of Friction Stir Weld Mictrstructures of a High Strength, Low Alloy Steel (HSLA-65),” Proceedings of the TWI 7th International FSW ...of HSLA-65 Steel by David R. Forrest and Matthew F. Sinfield N SW C C D -6 1- TR –2 00 8/ 02 N um er ic al S im ul at io n of G le eb le T or...Numerical Simulation of Gleeble Torsion Testing of HSLA-65 Steel by David R. Forrest and Matthew F. Sinfield i REPORT DOCUMENTATION PAGE Form

  10. A Torsion-Balance Search for Axion-Like Particles

    NASA Astrophysics Data System (ADS)

    Fleischer, Frank; Hoedl, Seth; Adelberger, Eric; Heckel, Blayne; Hoyle, C. D.; Shook, David; Swanson, Erik

    2012-03-01

    Axion-like particles can mediate macroscopic parity and time-reversal symmetry violating forces. We will present a search for such a force between polarized electrons and unpolarized atoms using a novel torsion pendulum operating in the unshielded magnetic field of an electromagnet. Laboratory bounds on this force were improved by more than 10 orders of magnitude for pseudoscalars heavier than 1,, and constraints on this force were established over a broad range of astrophysically interesting masses from 10,eV to 10,. Plans for a next generation of this experiment will be discussed.

  11. 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.

  12. Torsion pendulum measurements on viscoelastic materials during vacuum exposure

    NASA Technical Reports Server (NTRS)

    Ward, T. C.; Evans, M. L.

    1972-01-01

    A torsional pendulum apparatus designed for testing in situ in vacuum, the dynamic mechanical properties of materials is described. The application of this apparatus to an experimental program to measure the effects of vacuum on the mechanical properties of two ablator materials (a foamed material and a filled elastomer) and a solid rocket propellant (a filled elastomer) is presented. Results from the program are discussed as to the effects of vacuum on the mechanical properties of these three materials. In addition, time-temperature-superposition, as a technique for accelerating vacuum induced changes in mechanical properties, is discussed with reference to the three materials tested in the subject program.

  13. Stresses around large cut-outs in torsion boxes

    NASA Technical Reports Server (NTRS)

    Kuhn, Paul; Moggio, Edwin M

    1946-01-01

    The problem treated here is that of the stresses in a torsion box with a large rectangular cut-out. The theoretical treatment is confined to stresses termed the 'primary stresses.' Comparison of the theoretical results with strain gage data for a series of cut-outs indicates that the primary stresses are probably adequate for designing the major part of the structure, the only important exception being in the design of the cover sheet in the full section adjacent to the cut-out.

  14. 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.

  15. Quantum gravity with torsion and non-metricity

    NASA Astrophysics Data System (ADS)

    Pagani, C.; Percacci, R.

    2015-10-01

    We study the renormalization of theories of gravity with an arbitrary (torsional and non-metric) connection. The class of actions we consider is of the Palatini type, including the most general terms with up to two derivatives of the metric, but no derivatives of the connection. It contains 19 independent parameters. We calculate the one-loop beta functions of these parameters and find their fixed points. The Holst subspace is discussed in some detail and found not to be stable under renormalization. Some possible implications for ultraviolet and infrared gravity are discussed.

  16. 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

  17. 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

  18. Torsional Detwinning Domino in Nanotwinned One-Dimensional Nanostructures.

    PubMed

    Zhou, Haofei; Li, Xiaoyan; Wang, Ying; Liu, Zishun; Yang, Wei; Gao, Huajian

    2015-09-09

    How to maintain sustained deformation in one-dimensional nanostructures without localized failure is an important question for many applications of nanotechnology. Here we report a phenomenon of torsional detwinning domino that leads to giant rotational deformation without localized failure in nanotwinned one-dimensional metallic nanostructures. This mechanism is demonstrated in nanotwinned Cu nanorods via molecular dynamics simulations, where coherent twin boundaries are transformed into twist boundaries and then dissolved one by one, resulting in practically unlimited rotational deformation. This finding represents a fundamental advance in our understanding of deformation mechanisms in one-dimensional metallic nanostructures.

  19. 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

    ..., and delayed urination. There is a lack of adequate data to establish general recognition of the safety... drug product that is labeled, represented, or promoted to relieve the symptoms of benign prostatic... drug product labeled, represented, or promoted for OTC use to relieve the symptoms of benign prostatic...

  20. 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

    ..., and delayed urination. There is a lack of adequate data to establish general recognition of the safety... drug product that is labeled, represented, or promoted to relieve the symptoms of benign prostatic... drug product labeled, represented, or promoted for OTC use to relieve the symptoms of benign prostatic...