Experimental validation of energy parameters in parabolic trough collector with plain absorber and analysis of heat transfer enhancement techniques

NASA Astrophysics Data System (ADS)

Bilal, F. R.; Arunachala, U. C.; Sandeep, H. M.

2018-01-01

The quantum of heat loss from the receiver of the Parabolic Trough Collector is considerable which results in lower thermal efficiency of the system. Hence heat transfer augmentation is essential which can be attained by various techniques. An analytical model to evaluate the system with bare receiver performance was developed using MATLAB. The experimental validation of the model resulted in less than 5.5% error in exit temperature using both water and thermic oil as heat transfer fluid. Further, heat transfer enhancement techniques were incorporated in the model which included the use of twisted tape inserts, nanofluid, and a combination of both for further enhancement. It was observed that the use of evacuated glass cover in the existing setup would increase the useful heat gain up to 5.3%. Fe3O4/H2O nanofluid showed a maximum enhancement of 56% in the Nusselt number for the volume concentration of 0.6% at highest Reynolds number. Similarly, twisted tape turbulators (with twist ratio of 2) taken alone with water exhibited 59% improvement in Nusselt number. Combining both the heat transfer augmentation techniques at their best values revealed the Nusselt number enhancement up to 87%. It is concluded that, use of twisted tape with water is the best method for heat transfer augmentation since it gives the maximum effective thermal efficiency amongst all for the range of Re considered. The first section in your paper

Superconducting flat tape cable magnet

DOEpatents

Takayasu, Makoto

2015-08-11

A method for winding a coil magnet with the stacked tape cables, and a coil so wound. The winding process is controlled and various shape coils can be wound by twisting about the longitudinal axis of the cable and bending following the easy bend direction during winding, so that sharp local bending can be obtained by adjusting the twist pitch. Stack-tape cable is twisted while being wound, instead of being twisted in a straight configuration and then wound. In certain embodiments, the straight length should be half of the cable twist-pitch or a multiple of it.

The effect of twisted-tape width on heat transfer and pressure drop for fully developed laminar flow

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

Chakroun, W.M.; Al-Fahed, S.F.

1996-07-01

A series of experiments was conducted to study the effect of twisted-tape width on the heat transfer and pressure drop with laminar flow in tubes. Data for three twisted-tape wavelengths, each with five different widths, have been collected with constant wall temperature boundary condition. Correlations for the friction factor and Nusselt number are also available. The correlations predict the experimental data to within 10 to 15 percent for the heat transfer and friction factor, respectively. The presence of the twisted tape has caused the friction factor to increase by a factor of 3 to 7 depending on Reynolds number andmore » the twisted-tape geometry. Heat transfer results have shown an increase of 1.5 to 3 times that of plain tubes depending on the flow conditions and the twisted-tape geometry. The width shows no effect on friction factor and heat transfer in the low range of Reynolds number but has a more pronounced effect on heat transfer at the higher range of Reynolds number. It is recommended to use loose-fit tapes for low Reynolds number flows instead of tight-fit in the design of heat exchangers because they are easier to install and remove for cleaning purposes.« less

Rotation analysis on large complex superconducting cables based on numerical modeling and experiments

NASA Astrophysics Data System (ADS)

Qin, Jinggang; Yue, Donghua; Zhang, Xingyi; Wu, Yu; Liu, Xiaochuan; Liu, Huajun; Jin, Huan; Dai, Chao; Nijhuis, Arend; Zhou, Chao; Devred, Arnaud

2018-07-01

The conductors used in large fusion reactors, e.g. ITER, CFETR and DEMO, are made of cable-in-conduit conductor (CICC) with large diameters up to about 50 mm. The superconducting and copper strands are cabled around a central spiral and then wrapped with stainless-steel tape of 0.1 mm thickness. The cable is then inserted into a jacket under tensile force that increases with the length of insertion. Because the cables are long and with a large diameter, the insertion force could reach values of about 40 kN. The large tensile force could lead to significant rotation forces. This may lead to an increase of the twist pitch, especially for the final one. Understanding the twist pitch variation is very important; in particular, the twist pitch of a cable inside a CICC strongly affects its properties, especially for Nb3Sn conductors. In this paper, a simplified numerical model was used to analyze the cable rotation, including material properties, cabling tension as well as wrap tension. Several rotation experiments with tensile force have been performed to verify the numerical results for CFETR CSMC cables. The results show that the numerical analysis is consistent with the experiments and provides the optimal cabling conditions for large superconducting cables.

Fibril stability in solutions of twisted -sheet peptides: a new kind of micellization in chiral systems

NASA Astrophysics Data System (ADS)

Nyrkova, I. A.; Semenov, A. N.; Aggeli, A.; Boden, N.

2000-10-01

The problem of fibril (fibre) formation in chiral systems is explored theoretically being supported by experiments on synthetic de novo 11-mer peptide forming self-assembled -sheet tapes. Experimental data unambiguously indicate that the tapes form fibrils of nearly monodisperse thickness ca. 8-10 nm. Fibril formation and stabilisation are attributed to inter-tape face-to-face attraction and their intrinsic twist, correspondingly. The proposed theory is capable of predicting the fibril aggregation number and its equilibrium twist in terms of molecular parameters of the primary tapes. The suggested novel mechanism of twist stabilisation of finite aggregates (fibrils) is different to the well-known stabilisation of micelles in amphiphilic systems, and it is likely to explain the formation and stability of fibrils in a wide variety of systems including proteinaceous amyloid fibres, sickle-cell hemoglobin fibres responsible for HbS anemia, corkscrew threads found in chromonics in the presence of chiral additives and native cellulose microfibrillar crystallites. The theory also makes it possible to extract the basic molecular parameters of primary tapes (inter-tape attraction energy, helical twist step, elastic moduli) from the experimental data.

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.

Structural modeling of HTS tapes and cables

NASA Astrophysics Data System (ADS)

Allen, N. C.; Chiesa, L.; Takayasu, M.

2016-12-01

Structural finite element analysis (FEA) has been used as an insightful tool to investigate the electromechanical behavior of HTS REBCO tapes and twisted stacked-tape cables under tension, torsion, bending and combined loads. A novel technique was developed for modeling the layered composite structure of the 2G tapes with structural solid-shell elements in ANSYS®. The FEA models produced detailed strain information for the REBCO superconducting layer which was then paired with an analytical model to predict the critical current performance of the 2G HTS tapes under various loads. Two commercially available HTS tapes (SuperPower and SuNAM) under tension, torsion and combined tension-torsion were first analyzed with FEA and compared with available experimental results at 77 K. A sharp critical current degradation was experienced at the yield strength of the tapes under tension and below a 100 mm twist-pitch under torsion. Combined tension-torsion loads had a more gradual degradation of critical current for twist-pitches of 115 mm or shorter but had a negligible difference compared to pure tension for longer twist-pitches. Using the structural solid-shell technique for modeling 2G tapes in ANSYS®, an FEA methodology for simulating full scale three-dimensional HTS stacked-tape cables under pure bending was created. A model of a Twisted-Stacked Tape Cable (TSTC), a configuration first proposed at MIT, was initially developed and then adapted to the slotted-core HTS Cable-In-Conduit Conductor produced by the ENEA laboratory in Italy. The numerical axial strain of the HTS REBCO tapes within the cables as calculated by FEA were found to agree with an analytical model for two cases: perfect-slip (frictionless) and no-slip (bonded). The ENEA CICC model was also compared with recent experimental critical current data at 77 K and was found to match best using a low friction coefficient of 0.02 indicating that the tapes within the cable freely slide with respect to each other helping to reduce the axial strain during bending.

Analytical investigation in bending characteristic of twisted stacked-tape cable conductor

NASA Astrophysics Data System (ADS)

Takayasu, Makoto; Chiesa, Luisa

2015-12-01

An analytical model to evaluate bending strains of a twisted stack-tape cable (TSTC) conductor has been developed. Through a comparison with experimental results obtained for a soldered 32-tape YBCO TSTC conductor, it has been found that a Perfect-Slip Model (PSM) taking into account the slipping between tapes in a stacked-tape cable during bending gives much better estimation of the bending performance compared to a No-Slip Model (NSM). In the PSM case the tapes can slip so that the internal longitudinal axial strain can be released. The longitudinal strains of compression and tension regions along the tape are balanced in one twist-pitch and cancel out evenly in a long cable. Therefore, in a cable the strains due to bending can be minimized. This is an important advantage of a TSTC conductor. The effect of the cable diameter size on the bending strain is also expected to be minor, and all tapes composing a TSTC conductor have the same strain response under bending, therefore the cable critical current can be characterized from a single tape behaviour.

Experimental investigation of laminar flow of viscous oil through a circular tube having integral axial corrugation roughness and fitted with twisted tapes with oblique teeth

NASA Astrophysics Data System (ADS)

Pal, Sagnik; Saha, Sujoy Kumar

2015-08-01

The experimental friction factor and Nusselt number data for laminar flow of viscous oil through a circular duct having integral axial corrugation roughness and fitted with twisted tapes with oblique teeth have been presented. Predictive friction factor and Nusselt number correlations have also been presented. The thermohydraulic performance has been evaluated. The major findings of this experimental investigation are that the twisted tapes with oblique teeth in combination with integral axial corrugation roughness perform significantly better than the individual enhancement technique acting alone for laminar flow through a circular duct up to a certain value of fin parameter.

Visualization of Flows in Packed Beds of Twisted Tapes

NASA Technical Reports Server (NTRS)

Hendricks, R. C.; Braun, M. J.; Peloso, D.; Athavale, M. M.; Mullen, R. L.

2002-01-01

A videotape presentation of the flow field in a packed bed of 48 twisted tapes which can be simulated by very thin virtual cylinders has been assembled. The indices of refraction of the oil and the Lucite twisted tapes were closely matched, and the flow was seeded with magnesium oxide particles. Planar laser light projected the flow field in two dimensions both along and transverse to the flow axis. The flow field was three dimensional and complex to describe, yet the most prominent finding was flow threads. It appeared that axial flow spiraled along either within the confines of a virtual cylindrical boundary or within the exterior region, between the tangency points, of the virtual cylinders. Random packing and bed voids created vortices and disrupted the laminar flow but minimized the entrance effects. The flow-pressure drops in the packed bed fell below the Ergun model for porous-media flows. Single-twisted-tape results of Smithberg and Landis (1964) were used to guide the analysis. In appendix A the results of several investigators are scaled to the Ergun model. Further investigations including different geometric configurations, computational fluid dynamic (CFD) gridding, and analysis are required.

The effective resistance between twisted superconducting filaments in tapes

NASA Astrophysics Data System (ADS)

Takács, S.; Iwakuma, M.; Funaki, K.

2001-05-01

We consider two mechanisms, which influence the effective resistance between crossing strands on flat cables or filaments in twisted tapes. The one-layer classical Rutherford-type cable and the tapes with twisted BSCCO filaments in silver matrix are taken as analogous cases. The amount of the matrix between strands or filaments increases the effective conductance compared with the direct current paths (determined by the touching area of the filaments). The increase factor is about two and can easily be suppressed by other effects, like the contact resistance between the superconductor and the matrix. The second mechanism is due to the existence of induced voltage between any points of crossing filaments. This leads to an additional effective conductance, proportional to the square of the total number of filaments. Both effects are not very important for isotropic superconductors, but due to the strong anisotropy of critical parameters they can dominate for high temperature superconductors. The first one may partially compensate the influence of the usually weaker critical current density perpendicular to the tape. The contribution due to the second effect can explain the higher resistivity of the matrix in BSCCO tapes compared with pure silver. It seems that to obtain low AC coupling losses in BSCCO tapes, structures with small filament number are required.

Dynamical structure of center-of-pressure trajectories with and without functional taping in children with cerebral palsy level I and II of GMFCS.

PubMed

Pavão, Silvia Leticia; Ledebt, Annick; Savelsbergh, Geert J P; Rocha, Nelci Adriana C F

2017-08-01

Postural control during quiet standing was examined in typical children (TD) and children with cerebral palsy (CP) level I and II of GMFCS. The immediate effect on postural control of functional taping on the thighs was analyzed. We evaluated 43 TD, 17 CP children level I, and 10 CP children level II. Participants were evaluated in two conditions (with and without taping). The trajectories of the center of pressure (COP) were analyzed by means of conventional posturography (sway amplitude, sway-path-length) and dynamic posturography (degree of twisting-and-turning, sway regularity). Both CP groups showed larger sway amplitude than the TD while only the CP level II showed more regular COP trajectories with less twisting-and-turning. Functional taping didn't affect sway amplitude or sway-path-length. TD children exhibited more twisting-and-turning with functional taping, whereas no effects on postural sway dynamics were observed in CP children. Functional taping doesn't result in immediate changes in quiet stance in CP children, whereas in TD it resulted in faster sway corrections. Children level II invest more attention in postural control than level I, and TD. While quiet standing was more automatized in children level I than in level II, both CP groups showed a less stable balance than TD. Copyright © 2017 Elsevier B.V. All rights reserved.

Temperature-and field dependent characterization of a twisted stacked-tape cable

NASA Astrophysics Data System (ADS)

Barth, C.; Takayasu, M.; Bagrets, N.; Bayer, C. M.; Weiss, K.-P.; Lange, C.

2015-04-01

The twisted stacked-tape cable (TSTC) is one of the major high temperature superconductor cable concepts combining scalability, ease of fabrication and high current density making it a possible candidate as conductor for large scale magnets. To simulate the boundary conditions of such a magnets as well as the temperature dependence of TSTCs a 1.16 m long sample consisting of 40, 4 mm wide SuperPower REBCO tapes is characterized using the ‘FBI’ (force-field-current) superconductor test facility of the Institute for Technical Physics of the Karlsruhe Institute of Technology. In a first step, the magnetic background field is cycled while measuring the current carrying capabilities to determine the impact of Lorentz forces on the TSTC sample performance. In the first field cycle, the critical current of the TSTC sample is tested up to 12 T. A significant Lorentz force of up to 65.6 kN m-1 at the maximal magnetic background field of 12 T result in a 11.8% irreversible degradation of the current carrying capabilities. The degradation saturates (critical cable current of 5.46 kA at 4.2 K and 12 T background field) and does not increase in following field cycles. In a second step, the sample is characterized at different background fields (4-12 T) and surface temperatures (4.2-37.8 K) utilizing the variable temperature insert of the ‘FBI’ test facility. In a third step, the performance along the length of the sample is determined at 77 K, self-field. A 15% degradation is obtained for the central part of the sample which was within the high field region of the magnet during the in-field measurements.

Wire and Packing Tape Sandwiches

ERIC Educational Resources Information Center

Rabinowitz, Sandy

2009-01-01

In this article, the author describes how students can combine craft wire with clear packing tape to create a two-dimensional design that can be bent and twisted to create a three-dimensional form. Students sandwich wire designs between two layers of tape. (Contains 1 online resource.)

[Effects of slow twisting needle insertion and tubing needle insertion at Neiguan (PC 6) on cardiovascular function: a comparative study].

PubMed

Ning, Shaoli; Zhao, Lihua; Xu, Lingjun; Huang, Yu; Pang, Yong; Huang, Dingjian

2016-01-01

To compare the effects between slow twisting needle insertion and tubing needle insertion. With cross-over design, 100 healthy young subjects (half male and half female) aged from 19 to 23 years were randomly divided into two groups by random digital table, 50 cases in each one. At the first stage, subjects in the group A were treated with slow twisting needle insertion while, subjects in,the group B were treated with tubing needle insertion. One week later, the procedure of second stage was performed alternately. The needle was inserted into Neiguan (PC 6) with two methods by one acupuncturist. The needle was retained for 5 min before removal. Five min before needle insertion as well as needle withdrawal and 30 min after needle withdrawal, ZXG-E automatic cardiovascular diagnostic apparatus was used to test cardiovascular function. At the tim of needle withdrawal, slow twisting needle insertion could improve effect work of kinetics (EWK), effective blood volume (BV) and reduce elastic expansion coefficient of blood vessel (FEK) and left ventricular spray blood impedance (VER), which was significantly different from tubing needle insertion (all P < 0.05). Thirty min after needle withdrawal, the differences of the indices of cardiovascular function between the two groups were not significant (all P > 0.05). The slow twisting needle insertion is significantly superior to tubing needle insertion on lowering vascular tension and VER, improving EWK and BV.

Comparing performance of mothers using simplified mid-upper arm circumference (MUAC) classification devices with an improved MUAC insertion tape in Isiolo County, Kenya.

PubMed

Grant, Angeline; Njiru, James; Okoth, Edgar; Awino, Imelda; Briend, André; Murage, Samuel; Abdirahman, Saida; Myatt, Mark

2018-01-01

A novel approach for improving community case-detection of acute malnutrition involves mothers/caregivers screening their children for acute malnutrition using a mid-upper arm circumference (MUAC) insertion tape. The objective of this study was to test three simple MUAC classification devices to determine whether they improved the sensitivity of mothers/caregivers at detecting acute malnutrition. Prospective, non-randomised, partially-blinded, clinical diagnostic trial describing and comparing the performance of three "Click-MUAC" devices and a MUAC insertion tape. The study took place in twenty-one health facilities providing integrated management of acute malnutrition (IMAM) services in Isiolo County, Kenya. Mothers/caregivers classified their child ( n =1040), aged 6-59 months, using the "Click-MUAC" devices and a MUAC insertion tape. These classifications were compared to a "gold standard" classification (the mean of three measurements taken by a research assistant using the MUAC insertion tape). The sensitivity of mother/caregiver classifications was high for all devices (>93% for severe acute malnutrition (SAM), defined by MUAC < 115 mm, and > 90% for global acute malnutrition (GAM), defined by MUAC < 125 mm). Mother/caregiver sensitivity for SAM and GAM classification was higher using the MUAC insertion tape (100% sensitivity for SAM and 99% sensitivity for GAM) than using "Click-MUAC" devices. Younden's J for SAM classification, and sensitivity for GAM classification, were significantly higher for the MUAC insertion tape (99% and 99% respectively). Specificity was high for all devices (>96%) with no significant difference between the "Click-MUAC" devices and the MUAC insertion tape. The results of this study indicate that, although the "Click-MUAC" devices performed well, the MUAC insertion tape performed best. The results for sensitivity are higher than found in previous studies. The high sensitivity for both SAM and GAM classification by mothers/caregivers with the MUAC insertion tape could be due to the use of an improved MUAC tape design which has a number of new design features. The one-on-one demonstration provided to mothers/caregivers on the use of the devices may also have helped improve sensitivity. The results of this study provide evidence that mothers/caregivers can perform sensitive and specific classifications of their child's nutritional status using MUAC. Clinical trials registration number: NCT02833740.

Experimental evaluation of heat transfer efficiency of nanofluid in a double pipe heat exchanger and prediction of experimental results using artificial neural networks

NASA Astrophysics Data System (ADS)

Maddah, Heydar; Ghasemi, Nahid

2017-12-01

In this study, heat transfer efficiency of water and iron oxide nanofluid in a double pipe heat exchanger equipped with a typical twisted tape is experimentally investigated and impacts of the concentration of nanofluid and twisted tape on the heat transfer efficiency are also studied. Experiments were conducted under the laminar and turbulent flow for Reynolds numbers in the range of 1000 to 6000 and the concentration of nanofluid was 0.01, 0.02 and 0.03 wt%. In order to model and predict the heat transfer efficiency, an artificial neural network was used. The temperature of the hot fluid (nanofluid), the temperature of the cold fluid (water), mass flow rate of hot fluid (nanofluid), mass flow rate of cold fluid (water), the concentration of nanofluid and twist ratio are input data in artificial neural network and heat transfer is output or target. Heat transfer efficiency in the presence of 0.03 wt% nanofluid increases by 30% while using both the 0.03 wt% nanofluid and twisted tape with twist ratio 2 increases the heat transfer efficiency by 60%. Implementation of various structures of neural network with different number of neurons in the middle layer showed that 1-10-6 arrangement with the correlation coefficient 0.99181 and normal root mean square error 0.001621 is suggested as a desirable arrangement. The above structure has been successful in predicting 72% to 97%of variation in heat transfer efficiency characteristics based on the independent variables changes. In total, comparing the predicted results in this study with other studies and also the statistical measures shows the efficiency of artificial neural network.

Optimizing the parameters of heat transmission in a small heat exchanger with spiral tapes cut as triangles and Aluminum oxide nanofluid using central composite design method

NASA Astrophysics Data System (ADS)

Ghasemi, Nahid; Aghayari, Reza; Maddah, Heydar

2018-07-01

The present study aims at optimizing the heat transmission parameters such as Nusselt number and friction factor in a small double pipe heat exchanger equipped with rotating spiral tapes cut as triangles and filled with aluminum oxide nanofluid. The effects of Reynolds number, twist ratio (y/w), rotating twisted tape and concentration (w%) on the Nusselt number and friction factor are also investigated. The central composite design and the response surface methodology are used for evaluating the responses necessary for optimization. According to the optimal curves, the most optimized value obtained for Nusselt number and friction factor was 146.6675 and 0.06020, respectively. Finally, an appropriate correlation is also provided to achieve the optimal model of the minimum cost. Optimization results showed that the cost has decreased in the best case.

Optimizing the parameters of heat transmission in a small heat exchanger with spiral tapes cut as triangles and Aluminum oxide nanofluid using central composite design method

NASA Astrophysics Data System (ADS)

Ghasemi, Nahid; Aghayari, Reza; Maddah, Heydar

2018-02-01

The present study aims at optimizing the heat transmission parameters such as Nusselt number and friction factor in a small double pipe heat exchanger equipped with rotating spiral tapes cut as triangles and filled with aluminum oxide nanofluid. The effects of Reynolds number, twist ratio (y/w), rotating twisted tape and concentration (w%) on the Nusselt number and friction factor are also investigated. The central composite design and the response surface methodology are used for evaluating the responses necessary for optimization. According to the optimal curves, the most optimized value obtained for Nusselt number and friction factor was 146.6675 and 0.06020, respectively. Finally, an appropriate correlation is also provided to achieve the optimal model of the minimum cost. Optimization results showed that the cost has decreased in the best case.

[Laryngeal Tube Position Shift after Chest Compression: Comparison of Fixation Methods Using Durapore Tape, Multipore Tape, or a Neck Tape].

PubMed

Seno, Hisayo; Komasawa, Nobuyasu; Fujiwara, Shunsuke; Miyazaki, Shinichiro; Tatsumi, Shinichi; Minami, Toshiaki

2015-05-01

The laryngeal tube (LT ; Smiths Medical, Minnesota, U. S. A) is an inflatable supraglottic device for emergency airway management such as during chest compression, the instability after insertion remains a problem. We investigated the effectiveness of three fixation methods of LT using a manikin and automated chest compressor. After 10-minute chest compression, LT without fixation was shifted by 0.4 ± 0.1 cm, which was greater than with Durapore tape (0.2 ± 0.1 cm), Multipore tape (0.2 ± 0.1 cm), or a neck tape (0.1 ± 0.1 cm). The shift of the position was smaller with neck tape fixation compared to Durapore or Multipore tape fixation. A fixation neck tape may be useful in stabilizing the inserted position of LT during cardiopulmonary resuscitation.

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

Hierarchical self-assembly of chiral rod-like molecules as a model for peptide β-sheet tapes, ribbons, fibrils, and fibers

PubMed Central

Aggeli, A.; Nyrkova, I. A.; Bell, M.; Harding, R.; Carrick, L.; McLeish, T. C. B.; Semenov, A. N.; Boden, N.

2001-01-01

A generic statistical mechanical model is presented for the self-assembly of chiral rod-like units, such as β-sheet-forming peptides, into helical tapes, which with increasing concentration associate into twisted ribbons (double tapes), fibrils (twisted stacks of ribbons), and fibers (entwined fibrils). The finite fibril width and helicity is shown to stem from a competition between the free energy gain from attraction between ribbons and the penalty because of elastic distortion of the intrinsically twisted ribbons on incorporation into a growing fibril. Fibers are stabilized similarly. The behavior of two rationally designed 11-aa residue peptides, P11-I and P11-II, is illustrative of the proposed scheme. P11-I and P11-II are designed to adopt the β-strand conformation and to self-assemble in one dimension to form antiparallel β-sheet tapes, ribbons, fibrils, and fibers in well-defined solution conditions. The energetic parameters governing self-assembly have been estimated from the experimental data using the model. The 8-nm-wide fibrils consist of eight tapes, are extremely robust (scission energy ≈200 kBT), and sufficiently rigid (persistence length l̃fibril ≈ 20–70 μm) to form nematic solutions at peptide concentration c ≈ 0.9 mM (volume fraction ≈0.0009 vol/vol), which convert to self-supporting nematic gels at c > 4 mM. More generally, these observations provide a new insight into the generic self-assembling properties of β-sheet-forming peptides and shed new light on the factors governing the structures and stability of pathological amyloid fibrils in vivo. The model also provides a prescription of routes to novel macromolecules based on a variety of self-assembling chiral units, and protocols for extraction of the associated energy changes. PMID:11592996

Numerical and Experimental Investigation of the Electromechanical Behavior of REBCO Tapes

NASA Astrophysics Data System (ADS)

Allen, N. C.; Chiesa, L.; Takayasu, M.

2015-12-01

To fully characterize the electromechanical behavior of a Twisted Stacked-Tape Cable (TSTC) it is important to understand the performance of the individual REBCO tapes under various loading conditions. Numerical modeling and experimentation have been used to investigate the electromechanical characteristics of two commercially available REBCO tapes (SuperPower and SuNAM). Tension and combined tension-torsion experiments on single tapes have been continued, from prior preliminary studies, to characterize their critical current behavior and mechanical strength. Additionally, structural finite element analysis was performed on single tapes under tension and combined tension-torsion to investigate the strain dependence of the critical current. The numerical results were compared to the experimental findings for validation. The SuNAM experimental data matched the numerical model very well while the SuperPower tape experienced degradation at lower stress and strain than predicted in the model. The Superpower tape also displayed greater variability in critical current between different samples as compared with the SuNAM tape.

Method for braze-joining spirally wound tapes to inner walls of heat exchanger tubes

DOEpatents

Garrison, Melton E.

1984-01-01

The present invention is directed to a method of fabricating heat exchanger tubes in which twisted tapes are utilized for promoting turbulence and heat transfer. The method of the present invention provides for the brazing of the tapes to the inner walls of the tubes for enhancing heat transfer between the fluid within the conduit and a fluid medium outside of the conduit by conduction through the tape. The braze joint of the present invention is coextensive with the tape over the entire length thereof within the conduit. The practice of the present invention is achieved by placing a filler wire of brazing metal along the tape at a location removed from the side walls and then heating the conduit and tape sufficiently to effect the displacement of the filler metal by wicking to the contact point between the tape and the conduit wall to form a braze joint coextensive with the length of the tape within the conduit. This arrangement provides maximum heat transfer and assures that the tape is in contact with the conduit over the entire common length thereof.

Method for braze-joining spirally wound tapes to inner walls of heat exchanger tubes

DOEpatents

Garrison, M.E.

1982-09-03

The present invention is directed to a method of fabricating heat exchanger tubes in which twisted tapes are utilized for promoting turbulence and heat transfer. The method of the present invention provides for the brazing of the tapes to the inner walls of the tubes for enhancing heat transfer between the fluid within the conduit and a fluid medium outside of the conduit by conduction through the tape. The braze joint of the present invention is coextensive with the tape over the entire length thereof within the conduit. The practice of the present invention is achieved by placing a filler wire of brazing metal along the tape at a location removed from the side walls and then heating the conduit and tape sufficiently to effect the displacement of the filler metal by wicking to the contact point between the tape and the conduit wall to form a braze joint coextensive with the length of the tape within the conduit. This arrangement provides maximum heat transfer and assures that the tape is in contact with the conduit over the entire common length thereof.

Some factors determining the effective resistance between strands in flat cables (or superconducting filaments in tapes)

NASA Astrophysics Data System (ADS)

Takács, S.; Iwakuma, M.; Funaki, K.

2000-04-01

Two effects are considered which can influence the effective resistance between crossing strands on flat cables or filaments in twisted tapes. As analogous cases, the one-layer Rutherford-type cable with classical superconductors and the tapes with twisted BSCCO filaments in a silver matrix in perpendicular magnetic fields are considered as a model. At first, the amount of the central core between the strands and the silver matrix between the filaments increases the effective conductance compared with the direct current paths, which is supposed to be proportional to the touching area of filaments. The increase factor is about two and can be easily suppressed by other effects, such as the contact resistance between the superconductor and the matrix. However, due to the strong anisotropy of critical parameters for high temperature superconductors, this effect can partially compensate the influence of the usually weaker critical current density perpendicular to the tape. The second effect is connected with the existence of the induced voltage between any points of crossing filaments. This leads to an additional effective conductance, proportional to the square of the total number of the filaments. This contribution is prevailing for the anisotropic superconductors. Therefore, to obtain low ac coupling losses in BSCCO tapes, structures with smaller filament number are required. This case is analogous to round structures, leading to ac losses proportional to the square of the layer number in the field direction.

Heat transfer and pressure drop comparison in tubes with transverse ribs and with twisted tape

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

Bolla, G.; De Giorgio, G.; Pedrocchi, E.

1973-11-01

A comparison on an experimental basis between two of the most promising heat transfer enhancement devices in tubes, carried out using gas as a coolant, is presented. The devices, transverse ribs and twisted tapes respectively, can be both classified as turbulence promoters. The Reynolds numbers investigated range from 10/sup 4/ to 3 x 10/sup 5/, an interval which covers the area of major interest for industrial applications. It is shown that transverse ribs allow better overall performances to be achieved; both of the devices, however, appear more effective than the flow rate increase. Moreover, it is emphasized that the twomore » types of turbulence promoters show a different behavior when the flow rate is varied with respect to the nominal operating conditions. (auth)« less

High performance twisted and coiled soft actuator with spandex fiber for artificial muscles

NASA Astrophysics Data System (ADS)

Yang, Sang Yul; Cho, Kyeong Ho; Kim, Youngeun; Song, Min-Geun; Jung, Ho Sang; Yoo, Ji Wang; Moon, Hyungpil; Koo, Ja Choon; Nam, Jae-do; Ryeol Choi, Hyouk

2017-10-01

This paper reports the twisted and coiled soft actuator (abbreviated with STCA) with spandex fiber. The STCA exhibits higher actuation strain at lower temperature than the previous nylon twisted and coiled soft actuators (abbreviated with NTCAs). While NTCAs are fabricated using a twist-insertion process until coils are formed, a new method is developed to fabricate the STCA using the ultra-stretch of spandex, whereby the STCA is twisted again after the coil has been formed. A 6-gear-twist-insertion device that increases the stability and the fabrication speed is developed to fabricate the STCA. The superior performance exhibited by the STCA is due to the 14% contraction strain of the bare spandex (bare nylon: 4%) and the low spring constant of 0.0115 N mm-1. The maximum tensile actuation strain of STCA was 45% at 130 °C, and the maximum specific work was 1.523 kJ kg-1 at 130 °C. STCA could repeatedly actuate 100 times with a strain change of less than 0.4%.

Performance investigation and comparison of different turbulator shapes in solar water heating collector system

NASA Astrophysics Data System (ADS)

Khargotra, Rohit; Dhingra, Sunil; Chauhan, Ranchan; Singh, Tej

2018-05-01

The effective use of solar energy is hindered by the intermittent nature of its availability, limiting its use and effectiveness in domestic and industrial applications especially in water heating. In the present paper, the performance of different turbulator shapes in solar water heating collector system has been studied experimentally and comparison on the output performance has been carried out. Effects of insertion of coil-spring turbulator on heat transfer rate, mass flow rate, heat gain by the fluid etc. is studied by disturbing the flow inside the absorber tubes in a solar flat plate collector. The coil-spring used as a turbulator is placed inside the absorber tube which creates a continuous swirling flow along the tube wall. The results of the heat transfer have been compared well with the available results. The heat transfer rate in the collector has been found to be increased by 18% to 70%. Solar water heater having inserts in the flow tubes perform better than the conventional plain ones. It has been observed that heat losses are reduced consequently increasing the thermal performance to about 70% over the plain water heater under same operating conditions. The coil-spring used as a turbulator is placed inside the riser tube while the twisted tape is inserted into the wire coil to create a continuous swirling flow along the tube wall. The results of the heat transfer have been compared with the available results. Solar water heater having inserts in the flow tubes perform better than the conventional plain ones.

The short-term effectiveness of balance taping on acute nonspecific low-back pain: A case report.

PubMed

Lee, Jung-Hoon

2017-12-01

Low back pain has a significant socioeconomic impact. Repetitive lifting, with combined twisting and flexion motions of the lumbar spine, increases the risk for low-back pain and injury to the supporting tissues. A 60-year-old male who presented with acute low-back pain, with a pain intensity of 6/10 on the visual analog scale (VAS) and an Oswestry disability index (ODI) score of 70%. The range of motion (ROM) of the lumbar spine on initial examination, relative to the normal peak ROM, was as follows: extension, 12°/30°; flexion, 15°/80°; left rotation, 15°/45°; and right rotation, 25°/45°. He was diagnosed as acute nonspecific low-back pain sustained with repetitive lifting, combining motions of flexion and twisting. The balance taping was applied for 16 h/day, on average, for 3 consecutive days was used as the primary treatment to manage the patient's low-back pain. The application of balance taping increased the range of motion of the lumbar spine as follows: flexion, from 15° to 77°; extension, from 12° to 27°; right rotation, from 25° to 45°; and left rotation, from 15° to 45°. The ODI score decreased from 70% to 0%, and the VAS score from 6/10 to 0. We propose that balance taping using kinesiology tape could serve as a complementary approach to other treatments for the treatment of acute nonspecific low-back pain. Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.

Design optimization of superconducting coils based on asymmetrical characteristics of REBCO tapes

NASA Astrophysics Data System (ADS)

Hong, Zhiyong; Li, Wenrong; Chen, Yanjun; Gömöry, Fedor; Frolek, Lubomír; Zhang, Min; Sheng, Jie

2018-07-01

Angle dependence Ic(B,θ) of superconducting tape is a crucial parameter to calculate the influence of magnetic field during the design of superconducting applications,. This paper focuses on the asymmetrical characteristics found in REBCO tapes and further applications based on this phenomenon. This paper starts with angle dependence measurements of different HTS tapes, asymmetrical characteristics are found in some of the testing samples. On basis of this property, optimization of superconducting coils in superconducting motor, transformer and insert magnet is discussed by simulation. Simplified experiments which represent the structure of insert magnet were carried out to prove the validity of numerical studies. Conclusions obtained in this paper show that the asymmetrical property of superconducting tape is quite important in design of superconducting applications, and optimized winding technique based on this property can be used to improve the performance of superconducting devices.

Performance Analysis of Water Based Copper Oxide Nano Fluids in Heat Exchanger with Twisted Insert

NASA Astrophysics Data System (ADS)

Ashok Reddy, K.; Hanmanthu, Bhukya

2018-03-01

A new experimental setup has been designed for conducting experiments in a copper round pipe heat exchanger with inner diameter di=14.5mm and outer diameter do=16mm and length L = 1720 mm . By using two copper oxide nano concentrations of 0.1% and 0.3% with water as based fluid, the heat transfer rates have been obtained with helical twisted insert H/D=5 in turbulent flow condition. Reynolds number and friction factor with pressure gradient have been evaluated. The heat transfer rates of 0.1% conc. Nano-fluid with insert was found to be 13.77% more when compared to water.

HiMAT structural development design methodology. [aeroelastic tailoring of the canard and wing box and distributed load tests

NASA Technical Reports Server (NTRS)

Price, M. A.

1979-01-01

In order to improve aerodynamic performance, a twist criterion was used to design the canard and wing lifting surfaces of two graphite-epoxy research aircraft. To meet that twist criterion, the lifting surfaces were tailored using graphite-epoxy tape. The outer surface of the aircraft is essentially constructed of 95 percent graphite epoxy materials. The analytical tools and methodology used to design those lifting surfaces are described. One aircraft was subjected to an 8g ground test in order to verify structural integrity and to determine how well the desired twist was achieved. Test results are presented and the reductions of both flight and ground strain test gages and their associated stresses are discussed.

Astronaut Rich Clifford inserts tape into payload high data recorder

NASA Image and Video Library

1994-04-14

STS059-09-012 (9-20 April 1994) --- On the Space Shuttle Endeavour's aft flight deck, astronaut Michael R. (Rich) Clifford, mission specialist, inserts a tape in the payload high rate recorder. Three of these state-of-the-art recorders captured four times the amount of data that could be radioed to the ground. The 183 tapes, each containing 40 megabytes of data, will be turned into images over the next year, and analyzed over the next decade. Clifford was joined in space by five other NASA astronauts for a week and a half of support to the Space Radar Laboratory (SRL-1)/STS-59 mission.

TVT ABBREVO: cadaveric study of tape position in foramen obturatum and adductor region.

PubMed

Hubka, Petr; Nanka, Ondrej; Masata, Jaromir; Martan, Alois; Svabik, Kamil

2016-07-01

The aim of the study was to describe fixation of the TVT ABBREVO and establish whether the tape penetrates through obturator muscles and membrane (obturator complex) into the adductor region and, if so, how far it penetrates. Eight formalin-embalmed female cadavers were used to simulate TVT ABBREVO surgery (totalling 16 insertions). Following tape insertion, dissection was performed and ends of the tape were identified. In cases of penetration, the length of tape penetrating into the adductor region was measured. Of the 16 cases, the tape ended in the obturator membrane in eight, in the internal obturator muscle in one, and penetrated through the obturator membrane into the external obturator muscle in five, where it remained. In two cases, it penetrated through the obturator internus muscle, obturator membrane and obturator externus muscle into the group of thigh adductors; one penetration was by 3 mm and the second by 10 mm. No contact with the obturator nerve or its branches was noted in any case. No TVT contact with the obturator nerve was noted; tape penetrated into the adductor region in two of the 16 cases.

Apparatus and method for loading and unloading multiple digital tape cassettes utilizing a removable magazine

DOEpatents

Lindenmeyer, C.W.

1993-01-26

An apparatus and method to automate the handling of multiple digital tape cassettes for processing by commercially available cassette tape readers and recorders. A removable magazine rack stores a plurality of tape cassettes, and cooperates with a shuttle device that automatically inserts and removes cassettes from the magazine to the reader and vice-versa. Photocells are used to identify and index to the desired tape cassette. The apparatus allows digital information stored on multiple cassettes to be processed without significant operator intervention.

Apparatus and method for loading and unloading multiple digital tape cassettes utilizing a removable magazine

DOEpatents

Lindenmeyer, Carl W.

1993-01-01

An apparatus and method to automate the handling of multiple digital tape cassettes for processing by commercially available cassette tape readers and recorders. A removable magazine rack stores a plurality of tape cassettes, and cooperates with a shuttle device that automatically inserts and removes cassettes from the magazine to the reader and vice-versa. Photocells are used to identify and index to the desired tape cassette. The apparatus allows digital information stored on multiple cassettes to be processed without significant operator intervention.

Roebel assembled coated conductor cables (RACC): Ac-Losses and current carrying potential

NASA Astrophysics Data System (ADS)

Frank, A.; Heller, R.; Goldacker, W.; Kling, A.; Schmidt, C.

2008-02-01

Low ac-loss HTS cables for transport currents well above 1 kA are required for application in transformers and generators and are taken into consideration for future generations of fusion reactor coils. Coated conductors (CC) are suitable candidates for high field application at an operation temperature in the range 50-77 K. Ac-field applications require cables with low ac-losses and hence twisting of the individual strands. We solved this problem using the Roebel technique. Short lengths of Roebel bar cables were prepared from industrial DyBCO and YBCO-CC. Meander shaped tapes of 4 or 5 mm width with twist pitches of 123 or 127 mm were cut from the 10 or 12 mm wide CC tapes using a specially designed tool. Eleven or twelve of these strands were assembled to a cable. The electrical and mechanical connection of the tapes was achieved using a silver powder filled conductive epoxy resin. Ac-losses of a short sample in an external ac-field were measured as a function of frequency and field amplitude as well as the coupling current decay time constant. We discuss the results in terms of available theories and compare measured time constants in transverse field with measured coupling losses. Finally the potential of this cable type for ac-use is discussed with respect to ac-losses and current carrying capability.

Experimentally determined transport and magnetization ac losses of small cable models constructed from YBCO coated conductors

NASA Astrophysics Data System (ADS)

Šouc, J.; Vojenčiak, M.; Gömöry, F.

2010-04-01

Several short cable models were constructed from YBCO coated conductor (YBCO CC) to study their basic dc and ac electrical properties. They were prepared using superconducting tapes helically wound on fiberglass former of different diameter (5, 8 and 10 mm) with different twist pitch (from 1.7 up to 2.4 cm). The number of parallel-connected tapes ranged from 1 up to 6. The standard length of the models was 11 cm. In one case a 35 cm long model has been manufactured in order to perform a bending test. We observed that the critical currents of the models were proportional to the number of tapes used for their construction. Transport and magnetization ac loss were measured at 36 and 72 Hz.

Comparison study of cable geometries and superconducting tape layouts for high-temperature superconductor cables

NASA Astrophysics Data System (ADS)

Ta, Wurui; Shao, Tianchong; Gao, Yuanwen

2018-04-01

High-temperature superconductor (HTS) rare-earth-barium-copper-oxide (REBCO) tapes are very promising for use in high-current cables. The cable geometry and the layout of the superconducting tapes are directly related to the performance of the HTS cable. In this paper, we use numerical methods to perform a comparison study of multiple-stage twisted stacked-tape cable (TSTC) conductors to find better cable structures that can both improve the critical current and minimize the alternating current (AC) losses of the cable. The sub-cable geometry is designed to have a stair-step shape. Three superconducting tape layouts are chosen and their transport performance and AC losses are evaluated. The magnetic field and current density profiles of the cables are obtained. The results show that arrangement of the superconducting tapes from the interior towards the exterior of the cable based on their critical current values in descending order can enhance the cable's transport capacity while significantly reducing the AC losses. These results imply that cable transport capacity improvements can be achieved by arranging the superconducting tapes in a manner consistent with the electromagnetic field distribution. Through comparison of the critical currents and AC losses of four types of HTS cables, we determine the best structural choice among these cables.

"Space slitter" for film or tape

NASA Technical Reports Server (NTRS)

Johnson, W. H.

1978-01-01

Device cuts film or tape into strips by guiding film in channel under cutting blades. Device is operated by lifting pressure bar to insert blades into film. Film is then pulled through blades. Cutter has potential uses in advertising, commercial art, and publishing fields.

Advances in In-Situ Inspection of Automated Fiber Placement Systems

NASA Technical Reports Server (NTRS)

Juarez, Peter D.; Cramer, K. Elliott; Seebo, Jeffrey P.

2016-01-01

The advent of Automated Fiber Placement (AFP) systems have aided the rapid manufacturing of composite aerospace structures. One of the challenges that AFP systems present is the uniformity of the deposited prepreg tape layers, which are prone to laps, gaps, overlaps and twists. The current detection modus operandi involves halting fabrication and performing a time consuming visual inspection of each tape layer. Typical AFP systems use a quartz lamp to heat the base layer to make the surface tacky as it deposits another tape layer. The idea was proposed to use the preheated base layer as a through transmission heat source and to inspect the newly added tape layer using a thermographic camera. As a preliminary study of this concept a laboratory proof of concept device was designed and constructed to simulate the through transmission heat source. Using the proof of concept device, we inspected an AFP-built uncured composite specimen with artificial manufacturing defects. This paper will discuss the results of this preliminary study and the implications involved with deploying a full-scale AFP inspection system.

REACTOR CONTROL SYSTEM

DOEpatents

MacNeill, J.H.; Estabrook, J.Y.

1960-05-10

A reactor control system including a continuous tape passing through a first coolant passageway, over idler rollers, back through another parallel passageway, and over motor-driven rollers is described. Discrete portions of fuel or poison are carried on two opposed active sections of the tape. Driving the tape in forward or reverse directions causes both active sections to be simultaneously inserted or withdrawn uniformly, tending to maintain a more uniform flux within the reactor. The system is particularly useful in mobile reactors, where reduced inertial resistance to control rod movement is important.

Nonlinear Behavior of a Shim Coil in an LTS/HTS NMR Magnet With an HTS Insert Comprising Double-Pancake HTS-Tape Coils

PubMed Central

Hahn, Seung-yong; Ahn, Min Cheol; Bascuñán, Juan; Yao, Weijun; Iwasa, Yukikazu

2010-01-01

This paper reports results, experimental and analytical, of the nonlinear behavior of a shim coil in the presence of an HTS coil assembled with double-pancake (DP) HTS-tape coils. The experimental results are from: 1) operation of a 700 MHz LTS/HTS NMR magnet (LH700) consisting of a 600 MHz LTS NMR magnet (L600) equipped with superconducting shim coils and a 100 MHz DP-assembled HTS insert (H100) and; 2) an experiment with a room-temperature (RT) Z1 shim coil coupled to a 50 MHz DP-as-sembled HTS insert (H50). A field mapping theory with a harmonic analysis is applied to interpret both results. Based on experimental results and analyses, we conclude that the screening-current-induced field (SCF) generated by a DP-assembled HTS insert is primarily responsible for the nonlinear behavior, including strength degradation, of a shim coil. PMID:20383282

Test of 60 kA coated conductor cable prototypes for fusion magnets

NASA Astrophysics Data System (ADS)

Uglietti, D.; Bykovsky, N.; Sedlak, K.; Stepanov, B.; Wesche, R.; Bruzzone, P.

2015-12-01

Coated conductors could be promising materials for the fabrication of the large magnet systems of future fusion devices. Two prototype conductors (flat cables in steel conduits), each about 2 m long, were manufactured using coated conductor tapes (4 mm wide) from Super Power and SuperOx, with a total tape length of 1.6 km. Each flat cable is assembled from 20 strands, each strand consisting of a stack of 16 tapes surrounded by two half circular copper profiles, twisted and soldered. The tapes were measured at 12 T and 4.2 K and the results of the measurements were used for the assessment of the conductor electromagnetic properties at low temperature and high field. The two conductors were assembled together in a sample that was tested in the European Dipole (EDIPO) facility. The current sharing temperatures of the two conductors were measured at background fields from 8 T up to 12 T and for currents from 30 kA up to 70 kA: the measured values are within a few percent of the values expected from the measurements on tapes (short samples). After electromagnetic cycling, T cs at 12 T and 50 kA decreased from about 12 K to 11 K (about 10%), corresponding to less than 3% of I c.

Investigating Delamination Migration in Composite Tape Laminates

NASA Technical Reports Server (NTRS)

Ratcliffe, James G.; DeCarvalho, Nelson V.

2014-01-01

A modification to a recently developed test specimen designed to investigate migration of a delamination between neighboring ply interfaces in tape laminates is presented. The specimen is a cross-ply laminated beam consisting of 40 plies with a polytetrafluoroethylene insert spanning part way along its length. The insert is located between a lower 0-degree ply (specimen length direction) and a stack of four 90-degree plies (specimen width direction). The modification involved a stacking sequence that promotes stable delamination growth prior to migration, and included a relocation of the insert from the specimen midplane to the interface between plies 14 and 15. Specimens were clamped at both ends onto a rigid baseplate and loaded on their upper surface via a piano hinge assembly, resulting in a predominantly flexural loading condition. Tests were conducted with the load-application point positioned at various locations along a specimen's span. This position affected the sequence of damage events during a test.

Preliminary Investigation of Longitudinal Differences in TEC and Scintillation at Transition Latitudes

DTIC Science & Technology

1991-04-04

AIR. j NO ABSOLUTE TEC. C: NEW SATELITE WINDOWS INSERTED. j - IAPEDRIVE PROBLEM. D: SOME DATA ON CHART NOT RECORDED ON TAPE. H = NPIB INTERFASE...PROBLEM. E: SOME DATA BROKEN UP. V 2 FLOPPY DISK/DRIVE PROBLEM. F: TAPE CHANGE. W - WRONG SATELITE WINDOWS. TOTAL HOURS OF ACTIVITY LEVEL 1:300 P - POWER...0 1 0 31 1 COMMENT’S: ADDITIONAL COMMENT’S. A: TAPE STOP * L1/L2 SCINTILLATION. B: GPS SYSTEM OFF THE AIR. O= N ABSOLUTE TEC. C: NEW SATELITE WINDOWS

Guidelines for Developing and Inserting Material Properties into the Code 65 Composite Material Database

DTIC Science & Technology

2011-12-01

kind of base fiber used Fab-ric uni, stitched, weave, woven roving, textile form, tape, prepreg Laminate Schedu le [0]10 [0]14 [0]36 Manufacturing...roving, textile form, tape, prepreg Laminate Schedule [0]10 [0]14 [0]36 Manufacturing Date 2006 Test Facility/Date 2007 Program of Record AHM&ST...9 Laminate Schedule .......................................................................................................10 Cure

Changes in implant stability using different site preparation techniques: twist drills versus piezosurgery. A single-blinded, randomized, controlled clinical trial.

PubMed

Stacchi, Claudio; Vercellotti, Tomaso; Torelli, Lucio; Furlan, Fabio; Di Lenarda, Roberto

2013-04-01

The objective of the present investigation was to longitudinally monitor stability changes of implants inserted using traditional rotary instruments or piezoelectric inserts, and to follow their variations during the first 90 days of healing. A randomized, controlled trial was conducted on 20 patients. Each patient received two identical, adjacent implants in the upper premolar area: the test site was prepared with piezosurgery, and the control site was prepared using twist drills. Resonance frequency analysis measurements were taken by a blinded operator on the day of surgery and after 7, 14, 21, 28, 42, 56, and 90 days. At 90 days, 39 out of 40 implants were osseointegrated (one failure in the control group). Both groups showed an initial decrease in mean implant stability quotient (ISQ) values: a shift in implant stability to increasing ISQ values occurred after 14 days in the test group and after 21 days in the control group. The lowest mean ISQ value was recorded at 14 days for test implants (97.3% of the primary stability) and at 21 days for the control implants (90.8% of the primary stability). ISQ variations with respect to primary stability differed significantly between the two groups during the entire period of observation: from day 14 to day 42, in particular, the differences were extremely significant (p < .0001). All 39 implants were in function successfully at the visit scheduled 1 year after insertion. The findings from this study suggest that ultrasonic implant site preparation results in a limited decrease of ISQ values and in an earlier shifting from a decreasing to an increasing stability pattern, when compared with the traditional drilling technique. From a clinical point of view, implants inserted with the piezoelectric technique demonstrated a short-term clinical success similar to those inserted using twist drills. © 2011 Wiley Periodicals, Inc.

Perioperative complications and early follow-up with 100 TVT-SECUR procedures.

PubMed

Neuman, Menahem

2008-01-01

Our objective was to evaluate the complications and early follow-up of the tension-free vaginal tape (TVT)-SECUR, a new minimally invasive anti-incontinence operative procedure. A prospective, observational, and consecutive patient series was conducted. Perioperative and 12-month postoperative data were prospectively collected for the first 50 patients against the next consecutive 50 patients, among which TVT-SECUR specific surgical measurements were adopted (Canadian Task Force classification 2). In private hospital operative theatres, the TVT-SECUR operation was performed. Patients with urodynamically proved stress urinary incontinence were enrolled in this study after detailed informed consent was given. The TVT-SECUR, in the hammock shape to mimic the TVT-obturator placement, yet with no skin incisions, required neither bladder catheterization nor intraoperative diagnostic cystoscopy. The clinical and surgical data of 100 consecutive patients with TVT-SECUR were collected prospectively. Two patients had urinary obstructions and needed surgical tape-tension relief. One patient had a 50 mL paravesical self-remitting hematoma. At the first-month postoperative follow-up appointment, the objective therapeutic failure rate for the TVT-SECUR procedure among the 50 patients was 20.0% (10 patients). But when the tape was placed close to the urethra with no space allowed in between, the failure rate in the second patient group went down to 8.0% (4 patients); yet no further postoperative bladder outlet obstruction was diagnosed. Four (8.0%) patients in the first group had vaginal wall penetration with the inserters, requiring withdrawal, reinsertion, and vaginal wall repair. This was avoided with the second patient group by facilitating the inserters' introduction by widening the submucosal tunnel to 12 mm. Six (12.0%) other patients in the first group needed postoperative trimming of a vaginally extruded tape segment, performed in the office with satisfactory results. This problem was addressed later by making the submucosal dissection deeper to avoid intimate proximity of the tape with the vaginal mucosa. Consequently the tape protrusion rate was reduced to 8% (4 patients). Five (10.0%) patients in the first group had unintended tape removal at the time of inserter removal, necessitating the use of a second TVT-SECUR. This was addressed by meticulous detachment of the inserter before its withdrawal, after which no further unintended tape displacements were recorded. No clinical signs for bowel, bladder, or urethral injuries; intraoperative bleeding; or postoperative infections were evident. Telephone interview at the end of 12 months postoperatively was completed with 44 (88.0%) of the first patient group and 46 (92%) of the second patient group. In all, 39 (88.6%) and 43 (93.5%) of the telephone-interviewed patients of the first and second groups, respectively, reported objective urinary continence. The TVT-SECUR, a new midurethral sling, was associated with early safety and efficacy problems. These were identified and rectified, to make the TVT-SECUR a safe and effective anti-incontinence procedure. Operative complications associated with the TVT, such as bladder penetration and postoperative outlet obstruction, and TVT-obturator complications, such as postoperative thigh pain and bladder outlet obstruction, may be reduced with the TVT-SECUR. The first 100 operations' cumulative data analysis yielded some insights, including the necessity of meticulous and proper dissection before placement of the tape and the need for applying minimal extra tension to the tape. However, long-term comparative data collection will be required to draw solid conclusions regarding the appropriate position of this operative technique within the spectrum of anti-incontinence operations.

Applications of Superconductivity and Impact on U.S. Economy

NASA Astrophysics Data System (ADS)

Selvamanickam, Venkat

2014-03-01

In the past few decades, low temperature superconducting wires (niobium-titanium) have enabled multibillion dollar industries such as magnetic resonance imaging and nuclear magnetic resonance spectroscopy which otherwise would not have been possible. High temperature superconductors (HTS) hold the promise of impacting even a larger market in diverse applications such as energy, health, military, telecommunication, transportation and research. HTS tapes are now being manufactured in quantities of few hundred kilometers annually with current carrying capacity of about 300 times that of copper wire of the same cross section. Power transmission cables up to few kilometers in length made with HTS tapes have already been inserted in the power grid world-wide. In the past few of years, tremendous advancements have occurred in nanoscale defect engineering in these thin film superconducting tapes that has led to a doubling of critical current performance in high magnetic fields and operating temperatures of interest for various applications. Technologies developed in this area have been successfully inserted in production HTS tapes by industry. With the availability of such high performance HTS tapes, a number of coil-based applications are now being aggressively pursued by several institutions. HTS coils enable power devices with high power density with significant weight, size and power benefits. Energy storage, generation, use, transformation and transmission applications as well as magnetic applications such as magnetic shields, plasma confinement, and ultra-high field magnets are becoming possible with the availability of high-performance HTS tapes. An overview of the development and use of superconductors in electric power and magnetic applications will be provided in this presentation.

Advances in Current Rating Techniques for Flexible Printed Circuits

NASA Technical Reports Server (NTRS)

Hayes, Ron

2014-01-01

Twist Capsule Assemblies are power transfer devices commonly used in spacecraft mechanisms that require electrical signals to be passed across a rotating interface. Flexible printed circuits (flex tapes, see Figure 2) are used to carry the electrical signals in these devices. Determining the current rating for a given trace (conductor) size can be challenging. Because of the thermal conditions present in this environment the most appropriate approach is to assume that the only means by which heat is removed from the trace is thru the conductor itself, so that when the flex tape is long the temperature rise in the trace can be extreme. While this technique represents a worst-case thermal situation that yields conservative current ratings, this conservatism may lead to overly cautious designs when not all traces are used at their full rated capacity. A better understanding of how individual traces behave when they are not all in use is the goal of this research. In the testing done in support of this paper, a representative flex tape used for a flight Solar Array Drive Assembly (SADA) application was tested by energizing individual traces (conductors in the tape) in a vacuum chamber and the temperatures of the tape measured using both fine-gauge thermocouples and infrared thermographic imaging. We find that traditional derating schemes used for bundles of wires do not apply for the configuration tested. We also determine that single active traces located in the center of a flex tape operate at lower temperatures than those on the outside edges.

High-performance superconductors for Fusion Nuclear Science Facility

DOE PAGES

Zhai, Yuhu; Kessel, Chuck; Barth, Christian; ...

2016-11-09

High-performance superconducting magnets play an important role in the design of the next step large-scale, high-field fusion reactors such as the fusion nuclear science facility (FNSF) and the spherical tokamak (ST) pilot plant beyond ITER. Here, Princeton Plasma Physics Laboratory is currently leading the design studies of the FNSF and the ST pilot plant study. ITER, which is under construction in the south of France, utilizes the state-of-the-art low temperature superconducting magnet technology based on the cable-in-conduit conductor design, where over a thousand multifilament Nb 3Sn superconducting strands are twisted together to form a high-current-carrying cable inserted into a steelmore » jacket for coil windings. We present design options of the high-performance superconductors in the winding pack for the FNSF toroidal field magnet system based on the toroidal field radial build from the system code. For the low temperature superconductor options, the advanced J cNb 3Sn RRP strands (J c > 1000 A/mm 2 at 16 T, 4 K) from Oxford Superconducting Technology are under consideration. For the high-temperature superconductor options, the rectangular-shaped high-current HTS cable made of stacked YBCO tapes will be considered to validate feasibility of TF coil winding pack design for the ST-FNSF magnets.« less

High-performance superconductors for Fusion Nuclear Science Facility

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

Zhai, Yuhu; Kessel, Chuck; Barth, Christian

High-performance superconducting magnets play an important role in the design of the next step large-scale, high-field fusion reactors such as the fusion nuclear science facility (FNSF) and the spherical tokamak (ST) pilot plant beyond ITER. Here, Princeton Plasma Physics Laboratory is currently leading the design studies of the FNSF and the ST pilot plant study. ITER, which is under construction in the south of France, utilizes the state-of-the-art low temperature superconducting magnet technology based on the cable-in-conduit conductor design, where over a thousand multifilament Nb 3Sn superconducting strands are twisted together to form a high-current-carrying cable inserted into a steelmore » jacket for coil windings. We present design options of the high-performance superconductors in the winding pack for the FNSF toroidal field magnet system based on the toroidal field radial build from the system code. For the low temperature superconductor options, the advanced J cNb 3Sn RRP strands (J c > 1000 A/mm 2 at 16 T, 4 K) from Oxford Superconducting Technology are under consideration. For the high-temperature superconductor options, the rectangular-shaped high-current HTS cable made of stacked YBCO tapes will be considered to validate feasibility of TF coil winding pack design for the ST-FNSF magnets.« less

Disposal of Chemical Agent Identification Sets at Rocky Mountain Arsenal, Colorado. Volume 2. Appendices A-D

DTIC Science & Technology

1983-08-01

N ENTER UNIT NURSER YOU ARE USING FOR THE DATA TAPE 11 FIGURE A-20 A-15 PMOMR TO P"IN? PROCES: DATA SHEET - DECOMED PIC CONTRL INSERT DATA TAPE IN...EXCHANGE/COOLER 70 CONTROL PANEL1 ACTUATORPFEELER 71 TV MONITOR 2 MOTOR 72 CART TOP3 PUMP 73 CIRCUIT BREAKER 4 VALVE 74 5 BELT 75 LIGHT6 SEAL 76 MIRAN 807

Ac-loss measurement of a DyBCO-Roebel assembled coated conductor cable (RACC)

NASA Astrophysics Data System (ADS)

Schuller, S.; Goldacker, W.; Kling, A.; Krempasky, L.; Schmidt, C.

2007-10-01

Low ac-loss HTS cables for transport currents well above 1 kA are required for application in transformers and generators and are taken into consideration for future generations of fusion reactor coils. Coated conductors (CC) are suitable candidates for high field application at an operation temperature around 50-77 K, which is a crucial precondition for economical cooling costs. We prepared a short length of a Roebel bar cable made of industrial DyBCO coated conductor (Theva Company, Germany). Meander shaped tapes of 4 mm width with a twist pitch of 122 mm were cut from 10 mm wide CC tapes using a specially designed tool. Eleven of these strands were assembled to a cable. The electrical and mechanical connection of the tapes was achieved using a silver powder filled conductive epoxy resin. Ac-losses of a short sample in an external ac field were measured as a function of frequency and field amplitude in transverse and parallel field orientations. In addition, the coupling current time constant of the sample was directly measured.

Artificial blood-flow controlling effects of inhomogeneity of twisted magnetic fields

NASA Astrophysics Data System (ADS)

Nakagawa, Hidenori; Ohuchi, Mikio

2017-06-01

We developed a blood-flow controlling system using magnetic therapy for some types of nervous diseases. In our research, we utilized overlapped extremely low frequency (ELF) fields for the most effective blood-flow for the system. Results showed the possibility that the inhomogeneous region obtained by overlapping the fields at 50 Hz, namely, a desirably twisted field revealed a significant difference in induced electromotive forces at the insertion points of electrodes. In addition, ELF exposures with a high inhomogeneity of the twisted field at 50 Hz out of phase were more effective in generating an induced electromotive difference by approximately 31%, as contrasted with the difference generated by the exposure in phase. We expect that the increase of the inhomogeneity of the twisted field around a blood vessel can produce the most effective electromotive difference in the blood, and also moderately affect the excitable cells relating to the autonomic nervous system for an outstanding blood-flow control in vivo.

One-loop transition amplitudes in the D1D5 CFT

NASA Astrophysics Data System (ADS)

Carson, Zaq; Hampton, Shaun; Mathur, Samir D.

2017-01-01

We consider the issue of thermalization in the D1D5 CFT. Thermalization is expected to correspond to the formation of a black hole in the dual gravity theory. We start from the orbifold point, where the theory is essentially free, and does not thermalize. In earlier work it was noted that there was no clear thermalization effect when the theory was deformed off the orbifold point to first order in the relevant twist perturbation. In this paper we consider the deformation to second order in the twist, where we do find effects that can cause thermalization of an initial perturbation. We consider a 1-loop process where two untwisted copies of the CFT are twisted to one copy and then again untwisted to two copies. We start with a single oscillator excitation on the initial CFT, and compute the effect of the two twists on this state. We find simple approximate expressions for the Bogoliubov coefficients and the behavior of the single oscillator excitation in the continuum limit, where the mode numbers involved are taken to be much larger than unity. We also prove a number of useful relationships valid for processes with an arbitrary number of twist insertions.

Active shape control of composite blades using shape memory actuation

NASA Astrophysics Data System (ADS)

Chandra, Ramesh

2001-10-01

This paper presents active shape control of composite beams using shape memory actuation. Shape memory alloy (SMA) bender elements trained to memorize bending shape were used to induce bending and twisting deformations in composite beams. Bending-torsion coupled graphite-epoxy and kevlar-epoxy composite beams with Teflon inserts were manufactured using an autoclave-molding technique. Teflon inserts were replaced by trained SMA bender elements. Composite beams with SMA bender elements were activated by heating these using electrical resistive heating and the bending and twisting deformations of the beams were measured using a mirror and laser system. The structural response of the composite beams activated by SMA elements was predicted using the Vlasov theory, where these beams were modeled as open sections with many branches. The bending moment induced by a SMA bender element was calculated from its experimentally determined memorized shape. The bending, torsion, and bending-torsion coupling stiffness coefficients of these beams were obtained using analytical formulation of an open-section composite beam with many branches (Vlasov theory).

Sunspot rotation. II. Effects of varying the field strength and twist of an emerging flux tube

NASA Astrophysics Data System (ADS)

Sturrock, Z.; Hood, A. W.

2016-09-01

Context. Observations of flux emergence indicate that rotational velocities may develop within sunspots. However, the dependence of this rotation on sub-photospheric field strength and twist remains largely unknown. Aims: We investigate the effects of varying the initial field strength and twist of an emerging sub-photospheric magnetic flux tube on the rotation of the sunspots at the photosphere. Methods: We consider a simple model of a stratified domain with a sub-photospheric interior layer and three overlying atmospheric layers. A twisted arched flux tube is inserted in the interior and is allowed to rise into the atmosphere. To achieve this, the magnetohydrodynamic equations are solved using the Lagrangian-remap code, Lare3d. We perform a parameter study by independently varying the sub-photospheric magnetic field strength and twist. Results: Altering the initial magnetic field strength and twist of the flux tube significantly affects the tube's evolution and the rotational motions that develop at the photosphere. The rotation angle, vorticity, and current show a direct dependence on the initial field strength. We find that an increase in field strength increases the angle through which the fieldlines rotate, the length of the fieldlines extending into the atmosphere, and the magnetic energy transported to the atmosphere. This also affects the amount of residual twist in the interior. The length of the fieldlines is crucial as we predict the twist per unit length equilibrates to a lower value on longer fieldlines. No such direct dependence is found when we modify the twist of the magnetic field owing to the complex effect this has on the tension force acting on the tube. However, there is still a clear ordering in quantities such as the rotation angle, helicity, and free energy with higher initial twist cases being related to sunspots that rotate more rapidly, transporting more helicity and magnetic energy to the atmosphere.

One-loop transition amplitudes in the D1D5 CFT

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

Carson, Zaq; Hampton, Shaun; Mathur, Samir D.

We consider the issue of thermalization in the D1D5 CFT. Thermalization is expected to correspond to the formation of a black hole in the dual gravity theory. We start from the orbifold point, where the theory is essentially free, and does not thermalize. In earlier work it was noted that there was no clear thermalization effect when the theory was deformed of the orbifold point to first order in the relevant twist perturbation. In this paper we consider the deformation to second order in the twist, where we do find effects that can cause thermalization of an initial perturbation. Wemore » consider a 1-loop process where two untwisted copies of the CFT are twisted to one copy and then again untwisted to two copies. We start with a single oscillator excitation on the initial CFT, and compute the effect of the two twists on this state. We find simple approximate expressions for the Bogoliubov coeffcients and the behavior of the single oscillator excitation in the continuum limit, where the mode numbers involved are taken to be much larger than unity. We also prove a number of useful relationships valid for processes with an arbitrary number of twist insertions.« less

One-loop transition amplitudes in the D1D5 CFT

DOE PAGES

Carson, Zaq; Hampton, Shaun; Mathur, Samir D.

2017-01-02

We consider the issue of thermalization in the D1D5 CFT. Thermalization is expected to correspond to the formation of a black hole in the dual gravity theory. We start from the orbifold point, where the theory is essentially free, and does not thermalize. In earlier work it was noted that there was no clear thermalization effect when the theory was deformed of the orbifold point to first order in the relevant twist perturbation. In this paper we consider the deformation to second order in the twist, where we do find effects that can cause thermalization of an initial perturbation. Wemore » consider a 1-loop process where two untwisted copies of the CFT are twisted to one copy and then again untwisted to two copies. We start with a single oscillator excitation on the initial CFT, and compute the effect of the two twists on this state. We find simple approximate expressions for the Bogoliubov coeffcients and the behavior of the single oscillator excitation in the continuum limit, where the mode numbers involved are taken to be much larger than unity. We also prove a number of useful relationships valid for processes with an arbitrary number of twist insertions.« less

Quality of life and objective outcome assessment in women with tape division after surgery for stress urinary incontinence

PubMed Central

Ulrich, Daniela; Bjelic-Radisic, Vesna; Höllein, Anna; Tamussino, Karl; Aigmüller, Thomas

2017-01-01

Background Midurethral tapes may cause long-term complications such as voiding dysfunction, groin pain, de novo urgency or mesh erosion, which necessitate a reoperation. There is a paucity of data regarding health related quality of life in patients undergoing tape removal. The aim of the study was to evaluate quality of life (QoL) and objective outcome after midurethral tape division or excision. Methods All patients who underwent a midurethral tape division for voiding difficulties, pain or therapy resistant de novo overactive bladder between 1999 and 2014 were invited for follow-up. A control group with a suburethral tape without division was established in a 1:2 ratio and matched for age, tape used and year of tape insertion. Patients completed the Kings´ Health Questionnaire (KHQ), Incontinence Outcome Questionnaire, Female Sexual Function Index Questionnaire and the Patient Global Impression of Improvement score. Results Tape division or excision was performed in 32 women. Overall, 15 (60%) of 25 women who were alive were available for clinical examination and completed the questionnaires. Tape division was performed for voiding dysfunction (n = 7), overactive bladder (n = 2), mesh extrusion (n = 3) and ongoing pain (n = 3). Median time to tape division/excision was 10 months. Three women in the tape division group had undergone reoperation for stress urinary incontinence (SUI). At a median follow-up of 11 years (IQR 9–13) subjective SUI rate was 53% (8/15 women) in the tape division group and 17% (5/30) in the control group (p = 0.016), with no significant differences in objective SUI rates between groups. With regard to quality of life, the study group had significantly worse scores in the SUI related domains role limitation, physical limitation, severity measures and social limitations (KHQ) compared to the control group. Conclusions Women needing tape division or excision have lower SUI related QoL scores compared to controls mostly because of higher subjective SUI rates. PMID:28346541

How to secure the connection between thoracostomy tube and drainage system?

PubMed

Li, Ka Ki Pat; Wong, Kit Shing John; Wong, Yau Hang Henry; Cheng, Ka Lok; So, Fung Ling; Lau, Chu Leung; Kam, Chak Wah

2014-01-01

Thoracostomy tube insertion is one of the common bedside procedures in emergency medicine and many acute specialties. Dislodgement of thoracostomy tube from the connection tube of chest drainage system is an important problem with potential complications such as contamination, infection and pneumothorax. Besides, mere loosening can also lead to malfunction. It is a common practice to tape the connection of the system. This study aimed to evaluate the materials and methods of connection of chest drain system to minimize drainage dislodgement. We conducted an experimental study to assess the tightness of the connection with various taping materials and methods. We selected three commonly used adhesive materials (3M™ Transpore™ Medical tape, 3M™ Micropore™ Medical tape, 3M™ Soft Cloth Tape on Liner) and three different methods (cross method, straight method, nylon band) to secure the junction between the thoracostomy tube and the bi-conical adaptor in the drainage system. The measured outcome was the weight causing visible loosening of the junction between thoracotomy tube and the adaptor. For each taping material and taping method, 10 trials were performed. The median weight required to disconnect the junction is 26.22 lb for Transpore™, 31.29 lb for Micropore™ and 32.44 lb for Soft Cloth Tape on Liner. A smaller force was required to disconnect if Transpore™ is used (P<0.001). There was no statistical significant difference between Micropore™ and Soft Cloth Tape on Liner (P=0.98). The median disconnecting force is 32.44 lb for straight taping method, 40.55 lb for cross taping method and 21.15 lb for plastic band. The cross-taping method was the more secure method (P<0.0001 when compared with plastic band) (P=0.033 when compared with straight method). Cross-taping is the most secure method among the tested varieties in connecting the thoracostomy tube to the chest drainage system. Transpore™ is not a recommended material for thoracostomy tube taping.

Experimental study of noise transmission into a general aviation aircraft

NASA Technical Reports Server (NTRS)

Vaicaitis, R.; Bofilios, D. A.; Eisler, R.

1984-01-01

The effect of add-on treatments on noise transmission into a cabin of a light aircraft was studied under laboratory conditions for diffuse and localized noise inputs. Results indicate that stiffening skin panels with honeycomb would provide on the average 3dB to 7 dB insertion loss over the most of selected frequency range H1 to 1000 Hz. Addition of damping tape on top of the honeycomb treatment increases insertion loss by 2dB to 3dB. Porous acoustic blankets show no attenuation of transmitted noise for frequencies below 300 Hz. Insertion of impervious vinyl septa between the layers of porous acoustic blankets do not provide additional noise reduction for frequencies up to about 500 Hz. Similar behavior was observed for noise barriers composed of urethane elastomer, decoupler foam and acoustic foam. A treatment composed from several layers of acoustic foams does not increase noise attenuation for the entire frequency range studied. An acoustic treatment composed of honeycomb panels, constrained layer damping tape, 2 to 3 inches of porous acoustic blankets, and limptrim which is isolated from the vibrations of the main fuselage structure seems to provide the best option for noise control.

The changing face of urinary continence surgery in England: a perspective from the Hospital Episode Statistics database.

PubMed

Withington, John; Hirji, Sadaf; Sahai, Arun

2014-08-01

To quantify changes in surgical practice in the treatment of stress urinary incontinence (SUI), urge urinary incontinence (UUI) and post-prostatectomy stress incontinence (PPI) in England, using the Hospital Episode Statistics (HES) database. We used public domain information from the HES database, an administrative dataset recording all hospital admissions and procedures in England, to find evidence of change in the use of various surgical procedures for urinary incontinence from 2000 to 2012. For the treatment of SUI, a general increase in the use of synthetic mid-urethral tapes, such as tension-free vaginal tape (TVTO) and transobturator tape (TOT), was observed, while there was a significant decrease in colposuspension procedures over the same period. The number of procedures to remove TVT and TOT has also increased in recent years. In the treatment of overactive bladder and UUI, there has been a significant increase in the use of botulinum toxin A and neuromodulation in recent years. This coincided with a steady decline in the recorded use of clam ileocystoplasty. A steady increase was observed in the insertion of artificial urinary sphincter (AUS) devices in men, related to PPI. Mid-urethral synthetic tapes now represent the mainstream treatment of SUI in women, but tape-related complications have led to an increase in procedures to remove these devices. The uptake of botulinum toxin A and sacral neuromodulation has led to fewer clam ileocystoplasty procedures being performed. The steady increase in insertions of AUSs in men is unsurprising and reflects the widespread uptake of radical prostatectomy in recent years. There are limitations to results sourced from the HES database, with potential inaccuracy of coding; however, these data support the trends observed by experts in this field. © 2014 The Authors. BJU International published by John Wiley & Sons Ltd on behalf of BJU International.

Thermo-chemical modelling of a village cookstove for design improvement

NASA Astrophysics Data System (ADS)

Honkalaskar, Vijay H.; Sohoni, Milind; Bhandarkar, Upendra V.

2014-05-01

Cookstove operation comprises three basic processes, namely combustion of firewood, natural air draft due to the buoyancy induced by the temperature difference between the hearth and its surroundings, and heat transfer to the pot, stove body and surrounding atmosphere. Owing to the heterogenous and unsteady burning of solid fuel, there exist nonlinear and dynamic interrelationships among these process parameters. A steady-state analytical model of the cookstove operation is developed for its design improvement by splitting the hearth into three zones to study char combustion, volatile combustion and heat transfer to the pot bottom separately. It comprises a total of seven relations corresponding to a thorough analysis of the three basic processes. A novel method is proposed to model the combustion of wood to mimic the realities closely. Combustion space above the fuel bed is split into 1000 discrete parts to study the combustion of volatiles by considering a set of representative volatile gases. Model results are validated by comparing them with a set of water boiling tests carried on a traditional cookstove in the laboratory. It is found that the major thrust areas to improve the thermal performance are combustion of volatiles and the heat transfer to the pot. It is revealed that the existing design dimensions of the traditional cookstove are close to their optimal values. Addition of twisted-tape inserts in the hearth of the cookstove shows an improvement in the thermal performance due to increase in the heat transfer coefficient to the pot bottom and improved combustion of volatiles.

Bleeding complication with the TVT-Exact procedure: a report of two cases.

PubMed

Masata, Jaromir; Svabik, Kamil; Martan, Alois

2015-02-01

Midurethral tension-free vaginal tapes (TVT), placed through the retropubic space or through the obturator foramina, are widely used for the surgical treatment of female stress urinary incontinence. Some complications are associated with retropubic tapes owing to the passage of the tape through the space of Retzius. One of the most frequent complications is bleeding, and if injury to major vessels is involved, this may be life-threatening. In 2010, the Gynecare TVT-Exact® Continence System was introduced onto the market, with a rigid trocar shaft measuring 3.0 mm in diameter. We have no clinical data regarding the complication rate, especially concerning bleeding, connected with this device; all data are related to the original size of the TVT inserter. The cases presented demonstrate that bleeding complications can occur with the TVT-Exact procedure.

Documentation for the machine-readable version of the catalog of supplemental stars to the Bonner Durchmusterung

NASA Technical Reports Server (NTRS)

Warren, W. H., Jr.

1980-01-01

The magnetic tape version of the Bonn catalog is described. The catalog contains a listing of supplemental stars having lower case letter designations following the BD numbers after which they have been inserted. A sample catalog is also presented.

Designing an artificial neural network using radial basis function to model exergetic efficiency of nanofluids in mini double pipe heat exchanger

NASA Astrophysics Data System (ADS)

Ghasemi, Nahid; Aghayari, Reza; Maddah, Heydar

2018-06-01

The present study aims at predicting and optimizing exergetic efficiency of TiO2-Al2O3/water nanofluid at different Reynolds numbers, volume fractions and twisted ratios using Artificial Neural Networks (ANN) and experimental data. Central Composite Design (CCD) and cascade Radial Basis Function (RBF) were used to display the significant levels of the analyzed factors on the exergetic efficiency. The size of TiO2-Al2O3/water nanocomposite was 20-70 nm. The parameters of ANN model were adapted by a training algorithm of radial basis function (RBF) with a wide range of experimental data set. Total mean square error and correlation coefficient were used to evaluate the results which the best result was obtained from double layer perceptron neural network with 30 neurons in which total Mean Square Error(MSE) and correlation coefficient (R2) were equal to 0.002 and 0.999, respectively. This indicated successful prediction of the network. Moreover, the proposed equation for predicting exergetic efficiency was extremely successful. According to the optimal curves, the optimum designing parameters of double pipe heat exchanger with inner twisted tape and nanofluid under the constrains of exergetic efficiency 0.937 are found to be Reynolds number 2500, twisted ratio 2.5 and volume fraction( v/v%) 0.05.

The low radioactivity link of the CUORE experiment

NASA Astrophysics Data System (ADS)

Andreotti, E.; Arnaboldi, C.; Barucci, M.; Brofferio, C.; Cosmelli, C.; Calligaris, L.; Capelli, S.; Clemenza, M.; Maiano, C.; Pellicciari, M.; Pessina, G.; Pirro, S.

2009-09-01

CUORE will be an array of 988 TeO2 bolometers (5 × 5 × 5 cm3) held at about 10 mK. It will study the very rare double β decay process from 130Te. The electrical connections of the array to the room temperature electronics will consist in about 2000 wires. We will describe the design and characterization of the 3 interconnection sectors going from the detectors to the mixing chamber, the coldest stage at which the array is thermally and mechanically anchored, and from the mixing chamber to room temperature. The lower part consists of a set of 2.3 m long, 50 μm thick, Cu-insulator tapes having PEN (Polyethylene 2.6 Naphthalate) substrate, on which a pattern of copper tracks are etched. The differential layout pattern chosen allows obtaining a signal cross talk between adjacent channels of about 0.024%, together with a capacitance of about 26 pF/m and a resistance larger than 200 GΩ/m. On the top of the mixing chamber, Cu-Kapton boards are used to join the tapes to the second upward-going 2 m long links, implemented with twisted NbTi wires, interwoven in a NOMEX® texture. NbTi-NOMEX link features about 100 pF/m and negligible level of cross-talk. The radioactivity content of Cu-PEN tapes, Cu-Kapton boards, NbTi-NOMEX ribbons and connectors has been investigated and found to be compliant with the experimental requirements. A mechanical study has been done to quote the vibration transmission properties of the highly packaged tapes.

Flow boiling with enhancement devices for cold plate coolant channel design

NASA Technical Reports Server (NTRS)

Boyd, Ronald D., Sr.

1989-01-01

A research program to study the effect of enhancement devices on flow boiling heat transfer in coolant channels, which are heated either from the top side or uniformly, is discussed. Freon 11 is the working fluid involved. The specific objectives are: (1) examine the variations in both the mean and local (axial and circumferential) heat transfer coefficients for a circular coolant channel with either smooth walls or with both a twisted tape and spiral finned walls, (2) examine the effect channel diameter (and the length-to-diameter aspect ratio) variations for the smooth wall channel, and (3) develop an improved data reduction analysis.

Non-intrusive torque measurement for rotating shafts using optical sensing of zebra-tapes

NASA Astrophysics Data System (ADS)

Zappalá, D.; Bezziccheri, M.; Crabtree, C. J.; Paone, N.

2018-06-01

Non-intrusive, reliable and precise torque measurement is critical to dynamic performance monitoring, control and condition monitoring of rotating mechanical systems. This paper presents a novel, contactless torque measurement system consisting of two shaft-mounted zebra tapes and two optical sensors mounted on stationary rigid supports. Unlike conventional torque measurement methods, the proposed system does not require costly embedded sensors or shaft-mounted electronics. Moreover, its non-intrusive nature, adaptable design, simple installation and low cost make it suitable for a large variety of advanced engineering applications. Torque measurement is achieved by estimating the shaft twist angle through analysis of zebra tape pulse train time shifts. This paper presents and compares two signal processing methods for torque measurement: rising edge detection and cross-correlation. The performance of the proposed system has been proven experimentally under both static and variable conditions and both processing approaches show good agreement with reference measurements from an in-line, invasive torque transducer. Measurement uncertainty has been estimated according to the ISO GUM (Guide to the expression of uncertainty in measurement). Type A analysis of experimental data has provided an expanded uncertainty relative to the system full-scale torque of  ±0.30% and  ±0.86% for the rising edge and cross-correlation approaches, respectively. Statistical simulations performed by the Monte Carlo method have provided, in the worst case, an expanded uncertainty of  ±1.19%.

Implant Insertion Torque: Its Role in Achieving Primary Stability of Restorable Dental Implants.

PubMed

Greenstein, Gary; Cavallaro, John

2017-02-01

A literature review was conducted to determine the role of insertion torque in attaining primary stability of dental implants. The review is comprised of articles that discussed the amount of torque needed to achieve primary implant stability in healed ridges and fresh extraction sockets prior to immediate implant loading. Studies were appraised that addressed the effects of minimum and maximum forces that can be used to successfully place implants. The minimum torque that can be employed to attain primary stability is undefined. Forces ≥30 Ncm are routinely used to place implants into healed ridges and fresh extraction sockets prior to immediate loading of implants. Increased insertion torque (≥50 Ncm) reduces micromotion and does not appear to damage bone. In general, the healing process after implant insertion provides a degree of biologic stability that is similar whether implants are placed with high or low initial insertion torque. Primary stability is desirable when placing implants, but the absence of micromotion is what facilitates predictable implant osseointegration. Increased insertion torque helps achieve primary stability by reducing implant micromotion. Furthermore, tactile information provided by the first surgical twist drill can aid in selecting the initial insertion torque to achieve predictable stability of inserted dental implants.

Hyperbolic-cosine waveguide tapers and oversize rectangular waveguide for reduced broadband insertion loss in W-band electron paramagnetic resonance spectroscopy. II. Broadband characterization

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

Sidabras, Jason W.; Anderson, James R.; Mainali, Laxman

Experimental results have been reported on an oversize rectangular waveguide assembly operating nominally at 94 GHz. It was formed using commercially available WR28 waveguide as well as a pair of specially designed tapers with a hyperbolic-cosine shape from WR28 to WR10 waveguide [R. R. Mett et al., Rev. Sci. Instrum. 82, 074704 (2011)]. The oversize section reduces broadband insertion loss for an Electron Paramagnetic Resonance (EPR) probe placed in a 3.36 T magnet. Hyperbolic-cosine tapers minimize reflection of the main mode and the excitation of unwanted propagating waveguide modes. Oversize waveguide is distinguished from corrugated waveguide, overmoded waveguide, or quasi-opticmore » techniques by minimal coupling to higher-order modes. Only the TE{sub 10} mode of the parent WR10 waveguide is propagated. In the present work, a new oversize assembly with a gradual 90° twist was implemented. Microwave power measurements show that the twisted oversize waveguide assembly reduces the power loss in the observe and pump arms of a W-band bridge by an average of 2.35 dB and 2.41 dB, respectively, over a measured 1.25 GHz bandwidth relative to a straight length of WR10 waveguide. Network analyzer measurements confirm a decrease in insertion loss of 2.37 dB over a 4 GHz bandwidth and show minimal amplitude distortion of approximately 0.15 dB. Continuous wave EPR experiments confirm these results. The measured phase variations of the twisted oversize waveguide assembly, relative to an ideal distortionless transmission line, are reduced by a factor of two compared to a straight length of WR10 waveguide. Oversize waveguide with proper transitions is demonstrated as an effective way to increase incident power and the return signal for broadband EPR experiments. Detailed performance characteristics, including continuous wave experiment using 1 μM 2,2,6,6-tetramethylpiperidine-1-oxyl in aqueous solution, provided here serve as a benchmark for other broadband low-loss probes in millimeter-wave EPR bridges.« less

New surgical technique for treatment of stress urinary incontinence TVT-ABBREVO from development to clinical experience.

PubMed

Waltregny, David; de Leval, Jean

2012-12-01

Tension-free suburethral tapes have revolutionized the surgical treatment of female stress urinary incontinence (SUI). These tapes are inserted by way of a retropubic or transobturator route. The inside-out tension-free vaginal tape transobturator approach, or TVT-Obturator system (TVT-O, Ethicon Women's Health and Urology, Somerville, NJ), was developed ten years ago with the aim of minimizing the risk of urinary tract injuries associated with retropubic and outside-in transobturator tapes while reproducibly ensuring minimal tissue dissection. Cadaveric studies have shown that the anatomical trajectory of the TVT-O tape is strictly perineal and courses away from neighboring obturator and pudendal neurovascular structures. Several meta-analyses have shown similar SUI cure rates after retropubic and transobturator tape procedures. Yet, the transobturator route may be associated with less voiding dysfunction, blood loss, bladder perforation, and shorter operating time. The original TVT-O procedure was modified with the aim of reducing the incidence of postoperative groin pain as well as the rather theoretical risk of obturator nerve injury. This modified procedure, named TVT-ABBREVO (Ethicon Women's Health and Urology, Somerville, NJ), utilizes a shortened, 12-cm-long polypropylene tape. In addition, perforation of the obturator membrane with the scissors and guide is avoided in order to reduce the depth of lateral dissection, and consequently, to maximize securing of the tape within the obturator muscular/aponeurotic structures. In a comparative anatomical study, it was indeed observed that the shorter tape traversed less muscular structures (with no or only a minimal amount of tape lying in the adductor muscles) than its original counterpart, while still consistently anchoring in the obturator membrane at a similarly safe distance from the obturator canal. In a single-center randomized clinical trial, after a 3-year minimum follow-up, the modified TVT-O procedure with a shorter tape and reduced dissection was found to be as safe and efficient as the primal procedure for treating female SUI, with less severe and frequent groin pain in the immediate postoperative period.

Spatial and Temporal Variations of a Screening Current Induced Magnetic Field in a Double-Pancake HTS Insert of an LTS/HTS NMR Magnet

PubMed Central

Ahn, Min Cheol; Yagai, Tsuyoshi; Hahn, Seungyong; Ando, Ryuya; Bascuñán, Juan; Iwasa, Yukikazu

2010-01-01

This paper presents experimental and simulation results of a screening current induced magnetic field (SCF) in a high temperature superconductor (HTS) insert that constitutes a low-/high-temperature superconductor (LTS/HTS) NMR magnet. In this experiment, the HTS insert, a stack of 50 double-pancake coils, each wound with Bi2223 tape, was operated at 77 K. A screening current was induced in the HTS insert by three magnetic field sources: 1) a self field from the HTS insert; 2) an external field from a 5-T background magnet; and 3) combinations of 1) and 2). For each field excitation, which induced an SCF, its axial field distribution and temporal variations were measured and compared with simulation results based on the critical state model. Agreement on field profile between experiment and simulation is satisfactory but more work is needed to make the simulation useful for designing shim coils that will cancel the SCF. PMID:20401187

High heat flux issues for plasma-facing components in fusion reactors

NASA Astrophysics Data System (ADS)

Watson, Robert D.

1993-02-01

Plasma facing components in tokamak fusion reactors are faced with a number of difficult high heat flux issues. These components include: first wall armor tiles, pumped limiters, diverter plates, rf antennae structure, and diagnostic probes. Peak heat fluxes are 15 - 30 MW/m2 for diverter plates, which will operate for 100 - 1000 seconds in future tokamaks. Disruption heat fluxes can approach 100,000 MW/m2 for 0.1 ms. Diverter plates are water-cooled heat sinks with armor tiles brazed on to the plasma facing side. Heat sink materials include OFHC, GlidcopTM, TZM, Mo-41Re, and niobium alloys. Armor tile materials include: carbon fiber composites, beryllium, silicon carbide, tungsten, and molybdenum. Tile thickness range from 2 - 10 mm, and heat sinks are 1 - 3 mm. A twisted tape insert is used to enhance heat transfer and increase the burnout safety margin from critical heat flux limits to 50 - 60 MW/m2 with water at 10 m/s and 4 MPa. Tests using rastered electron beams have shown thermal fatigue failures from cracks at the brazed interface between tiles and the heat sink after only 1000 cycles at 10 - 15 MW/m2. These fatigue lifetimes need to be increased an order of magnitude to meet future requirements. Other critical issues for plasma facing components include: surface erosion from sputtering and disruption erosion, eddy current forces and runaway electron impact from disruptions, neutron damage, tritium retention and release, remote maintenance of radioactive components, corrosion-erosion, and loss-of-coolant accidents.

To evaluate the safety and efficacy of the TVT-Secur procedure in the treatment of stress urinary incontinence in women.

PubMed

Sandhu, J S; Karan, S C; Maiti, G D; Dudeja, Puja

2017-01-01

The prevalence of stress urinary incontinence (SUI) in the middle-aged Indian women is around 16%. The use of transvaginal tapes (TVTs) has revolutionised the surgical management of SUI. Patients who undergo placement of the tape via the transobturator route often complain of persistent thigh pain at the site of trocar insertion. The use of minimally invasive tapes with a single suburethral incision reduces surgical trauma by eliminating thigh incisions, while maintaining the cure achieved by conventional TVTs. The study was conducted to test the efficacy and safety of minimally invasive TVT-Secur tape placement for treatment of SUI in women. 20 women with stress incontinence were implanted with TVT-Secur tapes and followed up for a year. The objective cure rate of SUI was 85% at the end of a year. The improvement in the patient satisfaction and Incontinence-specific QOL scores, of both Urogenital Distress Inventory (UDI-6) and Incontinence Impact Questionnaire-7 (IIQ-7), was statistically significant at 95% and 99% confidence levels. There were no complaints of thigh pain; however, there were intraoperative complications in the form of bladder perforation in 5% ( n  = 1), urethral injury in 5% ( n  = 1) and urethral tape exposure in 10% ( n  = 2), at 3 months requiring tape sectioning. These cure rates and complications are comparable to the standard TVT implantations at the end of a year, without thigh pain; however, a greater number of patients and a longer follow-up is required to see whether the long-term cure is maintained or not, before recommending the same as a standard of treatment.

Metal-as-insulation variant of no-insulation HTS winding technique: pancake tests under high background magnetic field and high current at 4.2 K

NASA Astrophysics Data System (ADS)

Lécrevisse, T.; Badel, A.; Benkel, T.; Chaud, X.; Fazilleau, P.; Tixador, P.

2018-05-01

In the framework of a project aiming at fabricating a 10 T high temperature superconducting (HTS) insert to operate in a 20 T background field, we are investigating the behavior of pancakes consisting of a REBCO HTS tape co-wound with a stainless steel tape (metal-as-insulation (MI) coil). The MI winding is inducing a significant turn-to-turn electrical resistance which helps to reduce the charging time delay. Despite this resistance, the self-protection feature of no-insulation coils is still enabled, thanks to the voltage limit of the power supply. We have built a single pancake coil representative of the pancake that will be used in the insert and performed tests under very high background magnetic field. Our coil experienced over 100 heater induced quenches without a measureable increase of its internal resistance. We have gathered stability and quench behavior data for magnetic fields and engineering current densities (je ) in the range of 0–17 T and 0–635 A mm‑2 respectively. We also present our very first experiments on the insert/outsert interaction in the case of a resistive magnet fault. We show that if self-protection of the MI winding is really effective in the case of a MI coil quench, a major issue comes from the outsert fault which induces a huge current inside the MI coil.

Gemini 9 crew in spacecraft with technicians closing hatches

NASA Technical Reports Server (NTRS)

1966-01-01

Technicians prepare to close the hatches on the Gemini 9-A spacecraft in the White Room atop Pad 19 after insertion of Astronauts Thomas P. Stafford (left) and Eugene A. Cernan. Liftoff was at 8:39 a.m., June 3, 1966. Humorous sign from backup crew, James A. Lovell Jr. and Edwin E. Aldrin Jr., was taped to the spacecraft.

Multi-channel Spiral Twist Extrusion (MCSTE): A Novel Severe Plastic Deformation Technique for Grain Refinement

NASA Astrophysics Data System (ADS)

El-Garaihy, W. H.; Fouad, D. M.; Salem, H. G.

2018-07-01

Multi-channel Spiral Twist Extrusion (MCSTE) is introduced as a novel severe plastic deformation (SPD) technique for producing superior mechanical properties associated with ultrafine grained structure in bulk metals and alloys. The MCSTE design is based on inserting a uniform square cross-sectioned billet within stacked disks that guarantee shear strain accumulation. In an attempt to validate the technique and evaluate its plastic deformation characteristics, a series of experiments were conducted. The influence of the number of MCSTE passes on the mechanical properties and microstructural evolution of AA1100 alloy were investigated. Four passes of MCSTE, at a relatively low twisting angle of 30 deg, resulted in increasing the strength and hardness coupled with retention of ductility. Metallographic observations indicated a significant grain size reduction of 72 pct after 4 passes of MCSTE compared with the as-received (AR) condition. Moreover, the structural uniformity increased with the number of passes, which was reflected in the hardness distribution from the peripheries to the center of the extrudates. The current study showed that the MCSTE technique could be an effective, adaptable SPD die design with a promising potential for industrial applications compared to its counterparts.

Multi-channel Spiral Twist Extrusion (MCSTE): A Novel Severe Plastic Deformation Technique for Grain Refinement

NASA Astrophysics Data System (ADS)

El-Garaihy, W. H.; Fouad, D. M.; Salem, H. G.

2018-04-01

Multi-channel Spiral Twist Extrusion (MCSTE) is introduced as a novel severe plastic deformation (SPD) technique for producing superior mechanical properties associated with ultrafine grained structure in bulk metals and alloys. The MCSTE design is based on inserting a uniform square cross-sectioned billet within stacked disks that guarantee shear strain accumulation. In an attempt to validate the technique and evaluate its plastic deformation characteristics, a series of experiments were conducted. The influence of the number of MCSTE passes on the mechanical properties and microstructural evolution of AA1100 alloy were investigated. Four passes of MCSTE, at a relatively low twisting angle of 30 deg, resulted in increasing the strength and hardness coupled with retention of ductility. Metallographic observations indicated a significant grain size reduction of 72 pct after 4 passes of MCSTE compared with the as-received (AR) condition. Moreover, the structural uniformity increased with the number of passes, which was reflected in the hardness distribution from the peripheries to the center of the extrudates. The current study showed that the MCSTE technique could be an effective, adaptable SPD die design with a promising potential for industrial applications compared to its counterparts.

Twisted trees and inconsistency of tree estimation when gaps are treated as missing data - The impact of model mis-specification in distance corrections.

PubMed

McTavish, Emily Jane; Steel, Mike; Holder, Mark T

2015-12-01

Statistically consistent estimation of phylogenetic trees or gene trees is possible if pairwise sequence dissimilarities can be converted to a set of distances that are proportional to the true evolutionary distances. Susko et al. (2004) reported some strikingly broad results about the forms of inconsistency in tree estimation that can arise if corrected distances are not proportional to the true distances. They showed that if the corrected distance is a concave function of the true distance, then inconsistency due to long branch attraction will occur. If these functions are convex, then two "long branch repulsion" trees will be preferred over the true tree - though these two incorrect trees are expected to be tied as the preferred true. Here we extend their results, and demonstrate the existence of a tree shape (which we refer to as a "twisted Farris-zone" tree) for which a single incorrect tree topology will be guaranteed to be preferred if the corrected distance function is convex. We also report that the standard practice of treating gaps in sequence alignments as missing data is sufficient to produce non-linear corrected distance functions if the substitution process is not independent of the insertion/deletion process. Taken together, these results imply inconsistent tree inference under mild conditions. For example, if some positions in a sequence are constrained to be free of substitutions and insertion/deletion events while the remaining sites evolve with independent substitutions and insertion/deletion events, then the distances obtained by treating gaps as missing data can support an incorrect tree topology even given an unlimited amount of data. Copyright © 2015 Elsevier Inc. All rights reserved.

The twisted diversion: a paralyzing complication

PubMed Central

Hiew, Kenneth; Glendinning, Richard; Parr, Nigel; Kumar, Manal

2013-01-01

Ileal conduit remains a widely used urinary diversion performed after radical cystectomy. However, complications of ileal conduits remain an important concern in urological surgery. We report a rare case of an ileal conduit stricture, which can have grim complications if unobserved during the operation. Following an initial operation of radical cystectomy and ileal conduit formation in France in 2011, an 80-year-old male travelled back to the UK after 4 months of general weakness and limb paralysis. Initial blood test shows life-threatening hyperkalemia and worsened renal function. Subsequent ultrasound KUB scan and loopogram revealed obstructive uropathy. The initial management includes intravenous antibiotics and bilateral nephrostomies were inserted to aid diversion of urine. A thorough surgical exploration revealed a twisted, fibrous mesenteric band adhered to the proximal part of the ileal conduit. Only one case report of ileal conduit stenosis was described many years after the procedure. PMID:24963928

Structures for handling high heat fluxes

NASA Astrophysics Data System (ADS)

Watson, R. D.

1990-12-01

The divertor is reconized as one of the main performance limiting components for ITER. This paper reviews the critical issues for structures that are designed to withstand heat fluxes > 5 MW/m 2. High velocity, sub-cooled water with twisted tape inserts for enhanced heat transfer provides a critical heat flux limit of 40-60 MW/m 2. Uncertainties in physics and engineering heat flux peaking factors require that the design heat flux not exceed 10 MW/m 2 to maintain an adequate burnout safety margin. Armor tiles and heat sink materials must have a well matched thermal expansion coefficient to minimize stresses. The divertor lifetime from sputtering erosion is highly uncertain. The number of disruptions specified for ITER must be reduced to achieve a credible design. In-situ plasma spray repair with thick metallic coatings may reduce the problems of erosion. Runaway electrons in ITER have the potential to melt actively cooled components in a single event. A water leak is a serious accident because of steam reactions with hot carbon, beryllium, or tungsten that can mobilize large amounts of tritium and radioactive elements. If the plasma does not shutdown immediately, the divertor can melt in 1-10 s after a loss of coolant accident. Very high reliability of carbon tile braze joints will be required to achieve adequate safety and performance goals. Most of these critical issues will be addressed in the near future by operation of the Tore Supra pump limiters and the JET pumped divertor. An accurate understanding of the power flow out of edge of a DT burning plasma is essential to successful design of high heat flux components.

Flow boiling with enhancement devices for cold plate coolant channel design

NASA Technical Reports Server (NTRS)

Boyd, Ronald D.; Turknett, Jerry C.; Smith, Alvin

1989-01-01

The effects of enhancement devices on flow boiling heat transfer in circular coolant channels, which are heated over a fraction of their perimeters, are studied. The variations were examined in both the mean and local (axial, and circumferential) heat transfer coefficients for a circular coolant channel with either smooth walls or with both a twisted tape and spiral finned walls. Improvements were initiated in the present data reduction analysis. These efforts should lead to the development of heat transfer correlations which include effects of single side heat flux and enhancement device configuration. It is hoped that a stage will be set for the study of heat transfer and pressure drop in single sided heated systems under zero gravity conditions.

Construction and Test Results of Coil 2 of a Three-Coil 800-MHz REBCO Insert for the 1.3-GHz High-Resolution NMR Magnet.

PubMed

Bascuñán, Juan; Michael, Philip; Hahn, Seungyong; Lecrevisse, Thibault; Iwasa, Yukikazu

2017-06-01

This paper focuses on the construction and test results of Coil 2 that is part of a trio of nested coils composing the REBCO 800 MHz insert. Upon its completion, the REBCO 800 MHz insert will be placed in the bore of a 500 MHz low temperature superconducting (LTS) NMR magnet (L500) to form the MIT 1.3 GHz high-resolution NMR magnet. Coil 2 is a stack of 32 double pancake (DP) coils wound with 6-mm wide REBCO tape using the no-insulation (NI) technique. Each pancake is wound on a stainless steel inner supporting ring to prevent the collapsing of its crossover due to the external pressure exerted by the winding pack. Coil 2 will be constructed in the following sequence: 1) after winding each DP will be individually tested in a bath of liquid nitrogen at atmospheric pressure to determine its current carrying capabilities; 2) DPs will be then assembled as a stack with interconnecting joints, and 3) as in Coil 1, each pancake will be overbanded with a stainless steel tape, this time to a thickness of 5 mm, thickness determined by a stress analysis previously performed. Finally the fully assembled Coil 2 will be tested in liquid nitrogen at 77 K and then in liquid helium at 4.2 K. We present here details of the stress analysis leading to the sizing of the DP inner supporting stainless steel ring and of the overbanding thickness required. Test results include coil index, critical current, charging time constant.

Fabrication of graphite/epoxy cases for orbit insertion motors

NASA Technical Reports Server (NTRS)

Schmidt, W. W.

1973-01-01

The fabrication procedures are described for filament-wound rocket motor cases, approximately 26.25 inches long by 25.50 inches diameter, utilizing graphite fibers. The process utilized prepreg tape which consists of Fortafil 4-R fibers in the E-759 epoxy resin matrix. This fabrication effect demonstrated an ability to fabricate high quality graphite/epoxy rocket motor cases in the 26.25 inch by 25.50 inch size range.

Endourethral MRI Guidance for Prostatic RF Ablation

DTIC Science & Technology

2005-06-01

head (3 cm wide) attached to a 24-cm plastic handle,. Copper tape and then covered with a coat of protective plastic. In addition, bazooka baluns made...in the perineum , advanced posterior surface. This arrangement was used to mimic the into the prostatic urethra, and fixated in the prostate by...are inserted through the perineum placed in the left lateral decubitus position to maximize and into the prostate gland, commonly under ultrasound

The role of suture cutout in the failure of meniscal root repair during the early post-operative period: a biomechanical study.

PubMed

Perez-Blanca, Ana; Prado Nóvoa, María; Lombardo Torre, Maximiano; Espejo-Reina, Alejandro; Ezquerro Juanco, Francisco; Espejo-Baena, Alejandro

2018-04-01

To assess the role of suture cutout in the mechanics of failure of the repaired posterior meniscal root during the early post-operative period when using sutures of different shape. Twenty medial porcine menisci were randomized in two groups depending on the suture shape used to repair the posterior root: thread or tape. The sutured menisci were subjected to cyclic loading (1000 cycles, (10, 30) N) followed by load-to-failure testing. Residual displacements, stiffness, and ultimate failure load were determined. During tests, the tissue-suture interface was recorded using a high-resolution camera. In cyclic tests, cutout progression at the suture insertion points was not observed for any specimen of either group and no differences in residual displacements were found between use of thread or tape. In load-to-failure tests, suture cutout started in all menisci at a load close to the ultimate failure and all specimens failed by suture pullout. Suture tape had a greater ultimate load with no other differences. In a porcine model of a repaired posterior meniscal root subjected to cyclic loads representative of current rehabilitation protocols in the early post-operative period under restricted loading conditions, suture cutout was not found as a main source of permanent root displacement when using suture thread or tape. Suture cutout progression started at high loading levels close to the ultimate load of the construct. Tape, with a meniscus-suture contact area larger than thread, produced higher ultimate load.

The defectiveness of measurement data in the inclinometer mesurement in the insertion-type aperture and an introduction about the crrection

NASA Astrophysics Data System (ADS)

Homma, H.; Fujisawa, K.; Chiba, S.; Ootsuka, Y.; Higuchi, K.; Suganuma, T.

2010-12-01

Since 1975, the insertion type borehole inclinometer has been used to measure an underground lateral deformation in the civil engineering works field in Japan. The borehole inclinometer is used for a lot of landslide investigations as an effective measuring instrument to judge the slide surface position and the rate of slip. On the other hand, it became popular to be able to gather cores at 100% collection rate by the core-pack-tube method having been developed in the drilling survey. As a result, because the grasp accuracy of geological features had improved greatly, it became clear there was a case where the measurement data of the borehole inclinometer did not obviously show the displacement of the ground. As a result,to correct data even if the method of setting up the guide pipe is examined so as not to generate defective data , some engineers where such the realities were understood have been examining it about the correction method. Therefore, there is a case where there is no standards united about the methods of measuring the insertion type borehole inclinometer, and defective data is used still as a result of the observation though the ratio of defective data has decreased. The Pubic Works Research Institute landslide team and three private company companies of Japan did a joint research from these on the generation of defective data between fiscal year 2008 and fiscal year 2009 to prevent it. And, they made the manual that brought the matter to do an appropriate borehole inclinometer (Insertion type borehole inclinometer measurement manual on the landslide ground). In various experiments executed by a joint research, to prevent defective data being generated, it has been understood that the installation of the guide pipe is most important. The following two problems occur if a defective installation of the guide pipe is caused. (1)S shape data in graph (2)Disorder of flat direction of displacement (1) Because filling work at the time of the guide pipe setting is not enough, a gap occurs between a drill hole and a guide pipe. The grout material of the cement system is used standard in Japan. However, the landslide mass flows out easily in general because there are a lot of cracks in addition to low the groundwater level. Therefore we work on filling with paccar, and it is necessary to let a guide pipe and the ground. (2)The direction of the displacement that data shows is different from the direction of the movement of the actual ground. In this data, the product of the guide pipe twists, and both of the twist when setting it up are causes of generation. However, it is almost impossible to prevent this. Therefore, the twist is corrected measuring the azimuth of the guide tube with a simple type borehole camera. The insertion type clinometer in the aperture is a measure used in many landslide, but a guide pipe and revision of certain setting of the ground and the torsion of the guide pipe are necessary to get right data. And, this manual may be useful internationally.

Non-Abelian string and particle braiding in topological order: Modular SL (3 ,Z ) representation and (3 +1 ) -dimensional twisted gauge theory

NASA Astrophysics Data System (ADS)

Wang, Juven C.; Wen, Xiao-Gang

2015-01-01

String and particle braiding statistics are examined in a class of topological orders described by discrete gauge theories with a gauge group G and a 4-cocycle twist ω4 of G 's cohomology group H4(G ,R /Z ) in three-dimensional space and one-dimensional time (3 +1 D ) . We establish the topological spin and the spin-statistics relation for the closed strings and their multistring braiding statistics. The 3 +1 D twisted gauge theory can be characterized by a representation of a modular transformation group, SL (3 ,Z ) . We express the SL (3 ,Z ) generators Sx y z and Tx y in terms of the gauge group G and the 4-cocycle ω4. As we compactify one of the spatial directions z into a compact circle with a gauge flux b inserted, we can use the generators Sx y and Tx y of an SL (2 ,Z ) subgroup to study the dimensional reduction of the 3D topological order C3 D to a direct sum of degenerate states of 2D topological orders Cb2 D in different flux b sectors: C3 D=⊕bCb2 D . The 2D topological orders Cb2 D are described by 2D gauge theories of the group G twisted by the 3-cocycle ω3 (b ), dimensionally reduced from the 4-cocycle ω4. We show that the SL (2 ,Z ) generators, Sx y and Tx y, fully encode a particular type of three-string braiding statistics with a pattern that is the connected sum of two Hopf links. With certain 4-cocycle twists, we discover that, by threading a third string through two-string unlink into a three-string Hopf-link configuration, Abelian two-string braiding statistics is promoted to non-Abelian three-string braiding statistics.

Microwave Tower Deflection Monitor

NASA Astrophysics Data System (ADS)

Truax, Bruce E.

1980-10-01

This paper describes an instrument which is capable of monitoring both the twist and lateral motion of a microwave tower. The Microwave Tower Deflection Monitor (MTDM) gives designers the capability of evaluating towers, both for troubleshooting purposes and comparison with design theory. The MTDM has been designed to operate on a broad range of tower structures in a variety of weather conditions. The instrument measures tower motion by monitoring the position of two retroreflectors mounted on the top of the tower. The two retroreflectors are located by scanning a laser beam in a raster pattern in the vicinity of the reflector. When a retroreflector is struck its position is read by a microprocessor and stored on a magnetic tape. Position resolution of better than .5 cm at 200 ft. has been observed in actual tests.

Helicopter In-Flight Monitoring System Second Generation (HIMS II).

DTIC Science & Technology

1983-08-01

acquisition cycle. B. Computer Chassis CPU (DEC LSI-II/2) -- Executes instructions contained in the memory. 32K memory (DEC MSVII-DD) --Contains program...when the operator executes command #2, 3, or 5 (display data). New cartridges can be inserted as required for truly unlimited, continuous data...is called bootstrapping. The software, which is stored on a tape cartridge, is loaded into memory by execution of a small program stored in read-only

Modified Mostardi approach with ultra-high-molecular-weight polyethylene tape for total hip arthroplasty provides a good rate of union of osteotomized fragments.

PubMed

Kuroda, Yutaka; Akiyama, Haruhiko; Nankaku, Manabu; So, Kazutaka; Matsuda, Shuichi

2015-07-01

A lateral approach is common in total hip arthroplasty because of the good exposure it provides and its low complication rates. However, a drawback of the procedure is that the abductor mechanism is damaged when the tendinous insertion of the abductor muscle is split. Here, we describe a wafer technique using ultra-high-molecular-weight polyethylene tape for promising reattachment of the abductor mechanism. We retrospectively evaluated 120 consecutive primary total hip arthroplasties performed using a modified Mostardi approach, which involved reattaching the trochanter using either a braided polyester suture (polyester suture group, n = 60) or ultra-high-molecular-weight polyethylene tape (UHMWPE tape group, n = 60). The osteotomized fragment was reattached by inducing bone-to-bone contact using 3-mm-wide tapes that were precisely tied with a double-loop sliding knot in conjunction with a cable gun tensioner. The abductor strength and radiographic union rate were postoperatively assessed at 4 weeks and 6 months, respectively. A statistically significant lower incidence of nonunion and cutout was observed in the UHMWPE group (0 and 5.0 %, respectively) compared to the polyester suture group (8.3 and 15 %, respectively). No differences in abductor strength either preoperatively or at 4 weeks postoperatively were observed between the groups. In radiographically healed patients, abductor strength at 4 weeks post-surgery exceeded preoperative strength. The recovery rate of hip abductor strength was 109.9 ± 34.3 % in union patients and 92.9 ± 23.3 % in nonunion patients, which was statistically significant. The mean Japanese Orthopedic Association hip scores improved from 48.6 to 86.8 in union patients and from 50.3 to 85.9 in nonunion patients at 1 year postoperatively; however, this difference was not significant. The modified Mostardi approach using ultra-high molecular weight polyethylene tape can promote successful union of the osteotomized fragment.

Active Hydrazine Vapor Sampler (AHVS)

NASA Technical Reports Server (NTRS)

Young, Rebecca C.; Mcbrearty, Charles F.; Curran, Daniel J.

1993-01-01

The Active Hydrazine Vapor Sampler (AHVS) was developed to detect vapors of hydrazine (HZ) and monomethylhydrazine (MMH) in air at parts-per-billion (ppb) concentration levels. The sampler consists of a commercial personal pump that draws ambient air through paper tape treated with vanillin (4-hydroxy-3-methoxybenzaldehyde). The paper tape is sandwiched in a thin cardboard housing inserted in one of the two specially designed holders to facilitate sampling. Contaminated air reacts with vanillin to develop a yellow color. The density of the color is proportional to the concentration of HZ or MMH. The AHVS can detect 10 ppb in less than 5 minutes. The sampler is easy to use, low cost, and intrinsically safe and contains no toxic material. It is most beneficial for use in locations with no laboratory capabilities for instrumentation calibration. This paper reviews the development, laboratory test, and field test of the device.

TVT-S in the U position--anatomical study.

PubMed

Hubka, Petr; Nanka, Ondrej; Martan, Alois; Grim, Milos; Zvarova, Jana; Masata, Jaromir

2011-02-01

The objective is to describe the anatomical position of tension-free vaginal tape Secur (TVT-S) in the U position regarding possible injury and fixation site. We placed TVT-S inserters bilaterally in 13 embalmed and five fresh frozen female bodies. After dissection, we measured distances from the obturator bundle. In embalmed bodies, the mean distance of TVT-S from the obturator bundle was 2.83 cm (standard deviation (SD) 0.87 cm) on the left, 2.92 cm (SD 1.24 cm) on the right. Perforation of the fascia of obturator internus muscle occurred in 38.5%. In fresh frozen bodies, results were fundamentally similar (p > 0.05). There is a risk of injury to the obturator bundle and urinary bladder during TVT-S; however, there is a significant risk of inserting the TVT-S inserter outside the obturator internus muscle (into the lesser pelvis). The position of TVT-S does not change significantly after legs mal-positioning.

An Analytical Technique to Elucidate Field Impurities From Manufacturing Uncertainties of an Double Pancake Type HTS Insert for High Field LTS/HTS NMR Magnets

PubMed Central

Hahn, Seung-yong; Ahn, Min Cheol; Bobrov, Emanuel Saul; Bascuñán, Juan; Iwasa, Yukikazu

2010-01-01

This paper addresses adverse effects of dimensional uncertainties of an HTS insert assembled with double-pancake coils on spatial field homogeneity. Each DP coil was wound with Bi2223 tapes having dimensional tolerances larger than one order of magnitude of those accepted for LTS wires used in conventional NMR magnets. The paper presents: 1) dimensional variations measured in two LTS/HTS NMR magnets, 350 MHz (LH350) and 700 MHz (LH700), both built and operated at the Francis Bitter Magnet Laboratory; and 2) an analytical technique and its application to elucidate the field impurities measured with the two LTS/HTS magnets. Field impurities computed with the analytical model and those measured with the two LTS/HTS magnets agree quite well, demonstrating that this analytical technique is applicable to design a DP-assembled HTS insert with an improved field homogeneity for a high-field LTS/HTS NMR magnet. PMID:20407595

Validation of instrumentation to monitor dynamic performance of olympic weightlifters.

PubMed

Bruenger, Adam J; Smith, Sarah L; Sands, William A; Leigh, Michael R

2007-05-01

The purpose of this study was to validate the accuracy and reliability of the Weightlifting Video Overlay System (WVOS) used by coaches and sport biomechanists at the United States Olympic Training Center. Static trials with the bar set at specific positions and dynamic trials of a power snatch were performed. Static and dynamic values obtained by the WVOS were compared with values obtained by tape measure and standard video kinematic analysis. Coordinate positions (horizontal [X] and vertical [Y]) were compared on both ends (left and right) of the bar. Absolute technical error of measurement between WVOS and kinematic values were calculated (0.97 cm [left X], 0.98 cm [right X], 0.88 cm [left Y], and 0.53 cm [right Y]) for the static data. Pearson correlations for all dynamic trials exceeded r = 0.88. The greatest discrepancies between the 2 measuring systems were found to occur when there was twisting of the bar during the performance. This error was probably due to the location on the bar where the coordinates were measured. The WVOS appears to provide accurate position information when compared with standard kinematics; however, care must be taken in evaluating position measurements if there is a significant amount of twisting in the movement. The WVOS appears to be reliable and valid within reasonable error limits for the determination of weightlifting movement technique.

Dissipative cryogenic filters with zero dc resistance.

PubMed

Bluhm, Hendrik; Moler, Kathryn A

2008-01-01

The authors designed, implemented, and tested cryogenic rf filters with zero dc resistance, based on wires with a superconducting core inside a resistive sheath. The superconducting core allows low frequency currents to pass with negligible dissipation. Signals above the cutoff frequency are dissipated in the resistive part due to their small skin depth. The filters consist of twisted wire pairs shielded with copper tape. Above approximately 1 GHz, the attenuation is exponential in omega, as typical for skin depth based rf filters. By using additional capacitors of 10 nF per line, an attenuation of at least 45 dB above 10 MHz can be obtained. Thus, one single filter stage kept at mixing chamber temperature in a dilution refrigerator is sufficient to attenuate room temperature black body radiation to levels corresponding to 10 mK above about 10 MHz.

A Fracture Mechanics and Crack Propagation Approach to the Study of Overconsolidated Clays.

DTIC Science & Technology

1985-02-01

Once the length of the crack and the critical shearing stress are known a solution due to Erdogan and Ratwani 161 allows one to compute KIIc. lia... tape inserted in them to prevent hydrostatic pressure from closing and healing the crack. The specimens were then placed in a special cell where they...Theory, NASA Report, Grant NAG-3-23. 6. Erdogan , F.E. and Ratwani, M. (1973). A Circumferential Crack in a Cylindrical Shell Under Torsion. Int. J. Fract

Laryngostrobovideography using a flexible laryngofiberscope performed in conjunction with the phonatory examination.

PubMed

Fukuda, H; Kawaida, M; Oki, K; Kano, S; Kawasaki, Y; Tsuji, H; Kohno, N

1990-06-01

The phonatory examination was performed while monitoring vocal fold vibration by laryngostrobovideography. Vocal fold vibration was video-taped by a laryngostroboscope and flexible laryngofiberscope inserted through the nasal cavity. Simultaneously, the phonatory examination was conducted with a phonation analyzer. The data were entered into a personal microcomputer via an A/D converter and analyzed to obtain the parameters of sound pitch, sound intensity and mean expiratory air flow volume, which were superimposed on the color video monitor screen.

Field of a helical Siberian Snake

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

Luccio, A.

1995-02-01

To preserve the spin polarization of a beam of high energy protons in a circular accelerator, magnets with periodic magnetic field, called Siberian Snakes are being used. Recently, it was proposed to build Siberian Snakes with superconducting helical dipoles. In a helical, or twisted dipole, the magnetic field is perpendicular to the axis of the helix and rotates around it as one proceeds along the magnet. In an engineering study of a 4 Tesla helical snake, the coil geometry is derived, by twisting, from the geometry of a cosine superconducting dipole. While waiting for magnetic measurement data on such amore » prototype, an analytical expression for the field of the helice is important, to calculate the particle trajectories and the spin precession in the helix. This model will also allow to determine the optical characteristics of the snake, as an insertion in the lattice of the accelerator. In particular, one can calculate the integrated multipoles through the magnet and the equivalent transfer matrix. An expression for the field in the helix body, i.e., excluding the fringe field was given in a classical paper. An alternate expression can be found by elaborating on the treatment of the field of a transverse wiggler obtained under the rather general conditions that the variables are separable. This expression exactly satisfies Maxwell`s div and curl equations for a stationary field, {del} {center_dot} B = 0, {del} x B = 0. This approach is useful in that it will allow one to use much of the work already done on the problem of inserting wigglers and undulators in the lattice of a circular accelerator.« less

Holographic calculation for large interval Rényi entropy at high temperature

NASA Astrophysics Data System (ADS)

Chen, Bin; Wu, Jie-qiang

2015-11-01

In this paper, we study the holographic Rényi entropy of a large interval on a circle at high temperature for the two-dimensional conformal field theory (CFT) dual to pure AdS3 gravity. In the field theory, the Rényi entropy is encoded in the CFT partition function on n -sheeted torus connected with each other by a large branch cut. As proposed by Chen and Wu [Large interval limit of Rényi entropy at high temperature, arXiv:1412.0763], the effective way to read the entropy in the large interval limit is to insert a complete set of state bases of the twist sector at the branch cut. Then the calculation transforms into an expansion of four-point functions in the twist sector with respect to e-2/π T R n . By using the operator product expansion of the twist operators at the branch points, we read the first few terms of the Rényi entropy, including the leading and next-to-leading contributions in the large central charge limit. Moreover, we show that the leading contribution is actually captured by the twist vacuum module. In this case by the Ward identity the four-point functions can be derived from the correlation function of four twist operators, which is related to double interval entanglement entropy. Holographically, we apply the recipe in [T. Faulkner, The entanglement Rényi entropies of disjoint intervals in AdS/CFT, arXiv:1303.7221] and [T. Barrella et al., Holographic entanglement beyond classical gravity, J. High Energy Phys. 09 (2013) 109] to compute the classical Rényi entropy and its one-loop quantum correction, after imposing a new set of monodromy conditions. The holographic classical result matches exactly with the leading contribution in the field theory up to e-4 π T R and l6, while the holographical one-loop contribution is in exact agreement with next-to-leading results in field theory up to e-6/π T R n and l4 as well.

Occurence of adverse events due to continuous glucose monitoring.

PubMed

Jadviscokova, Tereza; Fajkusova, Zuzana; Pallayova, Maria; Luza, Jiri; Kuzmina, Galina

2007-12-01

Continuous glucose monitoring (CGM) using transcutaneous sensors is becoming a sophisticated method to control and regulate glucose metabolism. The transcutaneous sensor of the CGM system (CGMS Medtronic Minimed, Northridge, CA, USA) is chosen to measure glucose concentration in interstitial fluid up to three days after insertion even though its function remains stable for a longer period. The question arises, which factors really limit the period of sensor insertion without unnecessary risk. The aim of this study was to assess any adverse events occurring in the course of 9 days after the sensor insertion. In a group of 22 healthy volunteers aged 21.8+/-1.30 y (mean +/- SE) a total of 26 sensors was inserted subcutaneously in gluteal or lumbar region for 9 days. Before insertion the site was sprayed with an antiseptic (Cutasept F, Bode Chemie, Hamburg, Germany). Local adverse reactions and disturbances in general condition were examined. In the course of 184 sensor-days, there were only minor local adverse events: hypersensitivity, itching, pain, redness, burning, subcutaneous hemorrhage. Additionally, sleep disturbances, attention deficits, problems related to the CGMS monitor, to adhesive tape and/or sensor were found. None of these resulted in sensor withdrawal. In 12 volunteers (55 %) no complications were observed. The sensor function measured according to electrical signals (ISIG) failed (always on day 1-2) in 4 cases (16 %). The present FDA approved 3-day insertion period for Medtronic transcutaneous sensor does not seem to limit its use and appears to be worth a careful revision.

Test of an 8.66-T REBCO Insert Coil with Overbanding Radial Build for a 1.3-GHz LTS/HTS NMR Magnet.

PubMed

Qu, Timing; Michael, Philip C; Bascuñán, Juan; Lécrevisse, Thibault; Guan, Mingzhi; Hahn, Seungyong; Iwasa, Yukikazu

2017-06-01

A 1.3-GHz/54-mm LTS/HTS NMR magnet, assembled with a 3-coil (Coils 1-3) 800-MHz HTS insert in a 500-MHz LTS NMR magnet, is under construction. The innermost HTS insert Coil 1 has a stack of 26 no-insulation (NI) double pancake (DP) coils wound of 6-mm wide and 75- μ m thick REBCO tapes. In order to keep the hoop strains on REBCO tape < 0.6% at an operating current I op of 250 A and in a field of 30.5 T, we overbanded each pancake in Coil 1 with a 6-mm wide, 76- μ m thick 304 stainless steel strip: 7-mm thick radial build for the central 18 pancakes, while 6-mm thick for the outer 2×17 pancakes. In this paper, Coil 1 was successfully tested at 77K and 4.2 K. In the 77-K test, the measured critical current was 35.7 A, determined by an E -field criterion of 0.1 μ V/cm. The center field magnet constant decreased from 34.2 mT/A to 29.3 mT/A, when I op increased from 5 A to 40 A. The field distribution at different I op along the z -axis was measured. The residual field distributions discharged from 10 A and 20 A were recorded. In the 4.2-K test, Coil 1 successfully generated a central field of 8.78 T at 255 A. The magnet constant is 34.4 mT/A, which is same as our designed value. The field homogeneity at the coil center within a ± 15-mm region is around 1700 ppm. This large error field must be reduced before field shimming is applied.

Morphological Comparison of U3O8 Ore Concentrates from Canada Key Lake and Namibia Sources

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

Schwartz, Daniel S.; Tandon, Lav; Martinez, Patrick Thomas

Uranium ore concentrates from two different sources were examined using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The ore powders are referred to as Namibia (id. no. 90036, LIMS id. no. 18775) and Canada Key Lake (id. no. 90019, LIMS id. no. 18774). Earlier work identified the ores as the U₃O₈ phase of uranium oxide using x-ray diffraction. Both sets of powders were in the form of dark brown to black powder fines. However, the Canada Key Lake concentrates contained larger chunks of material on the millimeter scale that were easily visible to the unaided eye. The powdersmore » were mounted for SEM examination by hand dispersing a small amount onto conductive sticky tape. Two types of applicators were used and compared: a fine-tipped spatula and a foam-tipped applicator. The sticky tape was on a standard SEM “tee” mount, which was tapped to remove loose contamination before being inserted into the SEM.« less

Black phosphorus as a saturable absorber for generating mode-locked fiber laser in normal dispersion regime

NASA Astrophysics Data System (ADS)

Latiff, A. A.; Rusdi, M. F. M.; Hisyam, M. B.; Ahmad, H.; Harun, S. W.

2016-11-01

This paper reports a few-layer black phosphorus (BP) as a saturable absorber (SA) or phase-locker in generating modelocked pulses from a double-clad ytterbium-doped fiber laser (YDFL). We mechanically exfoliated the BP flakes from BP crystal through a scotch tape, and repeatedly press until the flakes thin and spread homogenously. Then, a piece of BP tape was inserted in the cavity between two fiber connectors end facet. Under 810 mW to 1320 mW pump power, stable mode-locked operation at 1085 nm with a repetition rate of 13.4 MHz is successfully achieved in normal dispersion regime. Before mode-locked operation disappears above maximum pump, the output power and pulse energy is about 80 mW and 6 nJ, respectively. This mode-locked laser produces peak power of 0.74 kW. Our work may validates BP SA as a phase-locker related to two-dimensional nanomaterials and pulsed generation in normal dispersion regime.

Comparison of conventional twist drill protocol and piezosurgery for implant insertion: an ex vivo study on different bone types.

PubMed

Sagheb, Keyvan; Kumar, Vinay V; Azaripour, Adriano; Walter, Christian; Al-Nawas, Bilal; Kämmerer, Peer W

2017-02-01

The aim of this ex vivo study was to compare implant insertion procedures using piezosurgery and conventional drilling in different qualities of bone. Implant bed preparation time, generated heat, and primary implant stability were analyzed. Fresh ex vivo porcine bone block samples (cancellous, mixed, and cortical bone) were obtained. The bone quality was quantified by ultrasound transmission velocity (UTV). Each bone sample received three implants of the same diameter using each of the techniques of piezosurgery and conventional twist drills. Time for preparation was taken and the temperature while performing the osteotomy was measured using infrared spectroscopy. The primary implant stability after osteotomy was measured using resonance frequency analysis (RFA) and extrusion torque (ET). ANOVA with post hoc Tukey test was carried out to compare the values for the three different groups. The UTV values strongly correlated with the density of the bone samples. There was a significant increase in time (threefold, P < 0.05 [302 s vs. 122 s in cortical bone]) but no difference in the temperature for the piezo group (~37°C in cortical bone). Regardless of the osteotomy technique, there was a statistically significant increase in RFA and ET values in implants inserted in cancellous bone (RFA: piezo 77, drill 76; ET: piezo 22, drill 21), mixed bone (RFA: piezo 85, drill 86; ET: piezo 105, drill 61), and cortical bone (RFA: piezo 90, drill 87; ET piezo 184, drill 79) samples, respectively (P < 0.05). In between the different osteotomy groups, there was no difference in the RFA values but significant higher ET values in mixed/cortical bone samples in favor for the piezosurgery group. Piezosurgery and conventional implant bed drilling procedure do have similar mechanical outcomes regarding primary stability with high RFA values, but the preparation does need more time for piezosurgery group, so that piezosurgery might be a valuable tool in only very specific cases for implant bed preparation. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

A new FPGA architecture suitable for DSP applications

NASA Astrophysics Data System (ADS)

Liyun, Wang; Jinmei, Lai; Jiarong, Tong; Pushan, Tang; Xing, Chen; Xueyan, Duan; Liguang, Chen; Jian, Wang; Yuan, Wang

2011-05-01

A new FPGA architecture suitable for digital signal processing applications is presented. DSP modules can be inserted into FPGA conveniently with the proposed architecture, which is much faster when used in the field of digital signal processing compared with traditional FPGAs. An advanced 2-level MUX (multiplexer) is also proposed. With the added SLEEP MODE PASS to traditional 2-level MUX, static leakage is reduced. Furthermore, buffers are inserted at early returns of long lines. With this kind of buffer, the delay of the long line is improved by 9.8% while the area increases by 4.37%. The layout of this architecture has been taped out in standard 0.13 μm CMOS technology successfully. The die size is 6.3 × 4.5 mm2 with the QFP208 package. Test results show that performances of presented classical DSP cases are improved by 28.6%-302% compared with traditional FPGAs.

Carbon-based torsional and tensile artificial muscles driven by thermal expansion (presentation video)

NASA Astrophysics Data System (ADS)

Haines, Carter S.; Lima, Márcio D.; Li, Na; Spinks, Geoffrey M.; Foroughi, Javad; Madden, John D. W.; Kim, Shi-Hyeong; Fang, Shaoli; Jung de Andrade, Monica; Göktepe, Fatma; Göktepe, Ozer; Mirvakili, Seyed M.; Naficy, Sina; Lepró, Xavier; Oh, Jiyoung; Kozlov, Mikhail E.; Kim, Seon Jeong; Xu, Xiuru; Swedlove, Benjamin J.; Wallace, Gordon G.; Baughman, Ray H.

2014-03-01

High-performance artificial muscles have been produced from fibers having highly anisotropic thermal expansion. Inserting twist into these precursor fibers enables thermally-driven torsional actuation and can cause the formation of helical coils. Such coiled structures provide giant-stroke tensile actuation exceeding the 20% in-vivo contraction of natural muscles. This contraction is highly reversible, with over one million cycles demonstrated, and can occur without the hysteresis that plagues competing shape-memory and piezoelectric muscles. Several materials and composites are investigated, including low-cost, commercially-available muscle precursors, potentially facilitating thermally-responsive textiles that change porosity to provide wearer comfort.

A Test for Characterizing Delamination Migration in Carbon/Epoxy Tape Laminates

NASA Technical Reports Server (NTRS)

Ratcliffe, James G.; Czabaj, Michael W.; O'Brien, Thomas K.

2013-01-01

A new test method is presented for the purpose of investigating migration of a delamination between neighboring ply interfaces in fiber-reinforced, polymer matrix tape laminates. The test is a single cantilever beam configuration consisting of a cross-ply laminate with a polytetrafluoroethylene insert implanted at the mid-plane and spanning part way along the length of the specimen. The insert is located between a 0- degree ply (specimen length direction) and a stack of four 90-degree plies (specimen width direction). The specimen is clamped at both ends onto a rigid baseplate and is loaded on its upper surface via a piano hinge. Tests were conducted with the load-application point located on the intact portion of the specimen in order to initiate delamination growth onset followed by migration of the delamination to a neighboring 90/0 ply interface by kinking through the 90-degree ply stack. Varying this position was found to affect the distance relative to the load-application point at which migration initiated. In each specimen, migration initiated by a gradual transition of the delamination at the 0/90 interface into the 90-degree ply stack. In contrast, transition of the kinked crack into the 90/0 interface was sudden. Fractography of the specimens indicated that delamination prior to migration was generally mixed mode-I/II. Inspection of the kink surface revealed mode-I fracture. In general, use of this test allows for the observation of the growth of a delamination followed by migration of the delamination to another ply interface, and should thus provide a means for validating analyses aimed at simulating migration.

Characterizing Delamination Migration in Carbon/Epoxy Tape Laminates

NASA Technical Reports Server (NTRS)

Ratcliffe, James G.; Czabaj, Michael W.; Obrien, Thomas K.

2012-01-01

A new test method is presented for the purpose of investigating migration of a delamination between neighboring ply interfaces in fiber-reinforced, polymer matrix tape laminates. The test is a single cantilever beam configuration consisting of a cross-ply laminate with a polytetrafluoroethylene (PTFE) insert implanted at the mid-plane and spanning part way along the length of the specimen. The insert is located between a 0-degree ply (specimen length direction) and a stack of four 90-degree plies (specimen width direction). The specimen is clamped at both ends onto a rigid baseplate and is loaded on its upper surface via a piano hinge. Tests were conducted with the load-application point located on the intact portion of the specimen in order to initiate delamination growth onset followed by migration of the delamination to a neighboring 90/0 ply interface by kinking through the 90- degree ply stack. Varying this position was found to affect the distance relative to the load-application point at which migration initiated. In each specimen, migration initiated by a gradual transition of the delamination at the 0/90 interface into the 90- degree ply stack. In contrast, transition of the kinked crack into the 90/0 interface was sudden. Fractography of the specimens indicated that delamination prior to migration was generally mixed mode-I/II. Inspection of the kink surface revealed mode-I fracture. In general, use of this test allows for the observation of the growth of a delamination followed by migration of the delamination to another ply interface, and should thus provide a means for validating analyses aimed at simulating migration.

REBCO tape performance under high magnetic field

NASA Astrophysics Data System (ADS)

Benkel, Tara; Miyoshi, Yasuyuki; Chaud, Xavier; Badel, Arnaud; Tixador, Pascal

2017-08-01

New improvements in high temperature superconductors (HTS) make them a promising candidate for building the next generation of high field magnets. As the conductors became recently available in long length, new projects such as NOUGAT (new magnet generation to generate Tesla at low cost) were started. This project aims at designing and building an HTS magnet prototype generating 10 T inside a 20 T resistive magnet. In this configuration, severe mechanical stress is applied on the insert and its extremities are subject to a high transverse component of the field. Because the conductor has anisotropic properties, it has to be studied carefully under similar conditions as the final prototype. First, this paper presents both the NOUGAT project and its context. Then, it shows the experimental results on short HTS tapes studied under high magnetic field up to 23 T with varying orientation. These results allow validating the current margin of the prototype. Finally, a first wound prototype is presented with experimental results up to 200 A under 16 T. Contribution to the topical issue "Electrical Engineering Symposium (SGE 2016)", edited by Adel Razek

The effect of bronchoscope rotation on tracheal tube orientation at the glottic level in a mannequin.

PubMed

Wong, David T; Yau, Brian; Thapar, Shikha; Adhikary, Sanjib D

2010-10-01

This study examined the effect of external fibreoptic bronchoscope (FOB) rotations on endotracheal tube (ETT) orientations at the glottic level. Using a mannequin, a nasal FOB was inserted for image capture. A second FOB with a preloaded ETT taped to its top was inserted orally into mid-trachea. The FOB with the taped ETT was rotated as a unit in the axial plane to five different external angles (-90°, -45°, 0°, +45°, +90°). At each external rotation, the ETT was advanced into the trachea. The image of the ETT at the glottic level was captured. Endotracheal tube orientation was quantified according to the glottic zone faced by the ETT. The ETT orientations were compared amongst the five external FOB rotations using the Kruskal-Wallis Test, while the ETT orientations at -90°, -45°, +45°, and +90° FOB rotations were compared with 0° rotation using the Mann-Whitney U test. There was a significant difference in the ETT orientations amongst the five FOB rotations (P < 0.001). The ETT orientations at -90°, -45°, +45°, and +90° FOB rotations were different from the 0° rotation (P < 0.001 for all comparisons). A -90° FOB rotation was most effective in turning the ETT tip away from the right laryngeal structures and the interarytenoid tissue. With the ETT loaded on a FOB, rotation of the FOB prior to advancing the ETT is effective in changing the ETT orientation at the glottis. A -90° FOB rotation is most effective in turning the ETT tip away from the right laryngeal structures and interarytenoid tissue.

Genome-Wide Analysis of Transposon and Retroviral Insertions Reveals Preferential Integrations in Regions of DNA Flexibility.

PubMed

Vrljicak, Pavle; Tao, Shijie; Varshney, Gaurav K; Quach, Helen Ngoc Bao; Joshi, Adita; LaFave, Matthew C; Burgess, Shawn M; Sampath, Karuna

2016-04-07

DNA transposons and retroviruses are important transgenic tools for genome engineering. An important consideration affecting the choice of transgenic vector is their insertion site preferences. Previous large-scale analyses of Ds transposon integration sites in plants were done on the basis of reporter gene expression or germ-line transmission, making it difficult to discern vertebrate integration preferences. Here, we compare over 1300 Ds transposon integration sites in zebrafish with Tol2 transposon and retroviral integration sites. Genome-wide analysis shows that Ds integration sites in the presence or absence of marker selection are remarkably similar and distributed throughout the genome. No strict motif was found, but a preference for structural features in the target DNA associated with DNA flexibility (Twist, Tilt, Rise, Roll, Shift, and Slide) was observed. Remarkably, this feature is also found in transposon and retroviral integrations in maize and mouse cells. Our findings show that structural features influence the integration of heterologous DNA in genomes, and have implications for targeted genome engineering. Copyright © 2016 Vrljicak et al.

Anatomical investigations on intraosseous access in stillborns - Comparison of different devices and techniques.

PubMed

Fuchs, Zeynep; Scaal, Martin; Haverkamp, Heinz; Koerber, Friederike; Persigehl, Thorsten; Eifinger, Frank

2018-06-01

Intraosseous (IO)-access plays an alternative route during resuscitation. Our study was performed to investigate the successful rate of IO-access in preterm and term stillborns using different devices and techniques. The cadavers used were legal donations. 16 stillborns, median: 29.2 weeks (IQR 27.2-38.4) were investigated. Two different needles (a: Butterfly needle, 21G, Venofix ® Fa.Braun; b: Arrow ® EZ-IO ® 15G, Teleflex, Dublin, Ireland) were used. Needles were inserted i: manually, using a Butterfly needle; ii: manually, using EZ-IO ® needle or iii: using a battery-powered semi-automatic drill (Arrow ® EZ-IO ® ). Spectral-CT's were performed. The diameter of the corticalis was determined from the CT-images. Successful hit rates with 95% confidence intervals (CI) and odds ratios between the three methods were estimated using a generalised linear mixed model (GLMM). Estimated success rate was 61.1% (95%CI:39.7%-78.9%) for the Butterfly needle, 43.0% (95%CI:23.4%-65.0%) for hand-twisted EZ-IO ® screwing and 39.7% (95%CI:24.1-57.7%) for the semi-automatic drill (Arrow ® EZ-IO ® ), all referring to an average diameter of the corticalis of 1.2 mm. The odds of a correct position were 2.4 times higher (95%CI:0.8-7.6) when using the Butterfly needle than with the drill. In contrast, the odds of correct positioning when inserting the needle by hand were not significantly different from using the drill (odds ratio 1.1, 95%CI: 0.4-3.3). Neither of these effects nor the diameter of the corticalis with an odds ratio near one were significant in the model. Median diameter of the bone marrow cavity was 4.0 mm [IQR 3.3-4.7]. Intraosseous access for premature and neonatal infants could be best achieved by using a manually twisted Butterfly needle. Copyright © 2018 Elsevier B.V. All rights reserved.

Tension-free transobturator approach for female stress urinary incontinence.

PubMed

Cindolo, L; Salzano, L; Rota, G; Bellini, S; D'Afiero, A

2004-03-01

UraTape is a new sling for female stress urinary incontinence (SUI) inserted via a transobturator percutaneous approach. We report the safety, feasibility and short-term results of this new surgical procedure. UraTape (Porgès-Mentor) is a non-elastic polypropylene tape, with a silicone coated central part. The sling is placed tension-free under the mid-urethra and extended through the obturator foramen bypassing the posterior face of the ischiopubic ramus. From September 2002 to May 2003, 80 females affected by SUI associated with urethral hypermobility and without severe uro-genital prolapse (with cystocele 1st grade) received UraTape. Mean age was 56 (39-79) years. Sixty-two out of 80 had a positive Q tip test; 16/80 had recurrent incontinence after Burch or colpoplasty according to Kelly; 22/60 had mixed incontinence. Preoperative evaluations included: complete history and physical examination, urinalysis, urodynamic investigations, abdominal and pelvic ultrasound. Quality of life assessment was carried out pre- and postoperatively. Mean operative time was 16 (11-36) minutes. No major intraoperative complications were observed. One bladder neck laceration occurred and was treated intraoperatively. No cystoscopy was performed. Mean hospital postoperative stay time was 1.1 (1-6) days. All patients were examined periodically at 7, 30 and 90 days from intervention (mean follow-up 4 months, 1-8). There was no urethral erosion. One vaginal erosion with inguinal abscess was diagnosed and treated without removing the sling. Two de novo urge incontinence was observed. The objective and subjective cure rates were 92% and 97%; 96% expressed good quality of life (satisfied/very satisfied). This procedure is a safe, effective new technique for the treatment of female SUI. The easy technique, the short learning curve and the very high grade of satisfaction of the patients show that this approach is based upon effective anatomical and physiological criteria. Further follow-up is necessary in order to evaluate urodynamic changes and overall satisfaction.

Secure hemostasis in transhiatal esophagectomy for esophageal cancer with gauze packing.

PubMed

Hirahara, Noriyuki; Matsubara, Takeshi; Hari, Yoko; Fujii, Yusuke; Wake, Hitomi; Tajima, Yoshitsugu

2012-12-19

Transhiatal esophagectomy for esophageal cancer implies blind manipulation of the intrathoracic esophagus. We report a secure hemostatic method with gauze packing in transhiatal esophagectomy. The gauze-packing technique is utilized for hemostasis just after removal of the thoracic esophagus during transhiatal esophagectomy. After confirming cancer-free margins, the abdominal esophagus and cervical esophagus are transected. A vein stripper is inserted into the oral-side stump of the esophagus and led to exit from the abdominal-side stump of the esophagus. The vein stripper and the oral stump of the esophagus are affixed by silk thread. A polyester tape is then affixed to the vein stripper, as the polyester tape is left in the posterior mediastinum after removal of the esophagus toward the abdominal side. The polyester tape on the cervical side is ligated with gauze and the polyester tape is removed toward the abdominal side. The oral stump of gauze and new additional gauze are affixed. As the first gauze is pulled out from the abdominal side, the second gauze gets drawn from the cervical wound into the mediastinum. The posterior mediastinum is finally packed with gauze and possible bleeding at this site undergoes a complete astriction. The status of hemostasis with the gauze packing is checked by an observation of color and bloodstain on the gauze. Between January 2005 and February 2012, 13 consecutive patients with esophageal cancer underwent a transhiatal esophagectomy with the gauze-packing hemostatic technique. Hemostasis at the posterior mediastinum was performed successfully and quickly in all cases with this method, requiring up to four pieces of gauze for a complete hemostasis. Median required time for hemostasis was 1219 (range 1896 to 1293) seconds and estimated blood loss was 20.4 (range 15 to 25) ml during gauze packing. Our technique could minimize bleeding after the removal of the thoracic esophagus. The gauze-packing method is a simple and easy technique for secure hemostasis when performing a transhiatal esophagectomy.

Secure hemostasis in transhiatal esophagectomy for esophageal cancer with gauze packing

PubMed Central

2012-01-01

Background Transhiatal esophagectomy for esophageal cancer implies blind manipulation of the intrathoracic esophagus. We report a secure hemostatic method with gauze packing in transhiatal esophagectomy. Methods The gauze-packing technique is utilized for hemostasis just after removal of the thoracic esophagus during transhiatal esophagectomy. After confirming cancer-free margins, the abdominal esophagus and cervical esophagus are transected. A vein stripper is inserted into the oral-side stump of the esophagus and led to exit from the abdominal-side stump of the esophagus. The vein stripper and the oral stump of the esophagus are affixed by silk thread. A polyester tape is then affixed to the vein stripper, as the polyester tape is left in the posterior mediastinum after removal of the esophagus toward the abdominal side. The polyester tape on the cervical side is ligated with gauze and the polyester tape is removed toward the abdominal side. The oral stump of gauze and new additional gauze are affixed. As the first gauze is pulled out from the abdominal side, the second gauze gets drawn from the cervical wound into the mediastinum. The posterior mediastinum is finally packed with gauze and possible bleeding at this site undergoes a complete astriction. The status of hemostasis with the gauze packing is checked by an observation of color and bloodstain on the gauze. Results Between January 2005 and February 2012, 13 consecutive patients with esophageal cancer underwent a transhiatal esophagectomy with the gauze-packing hemostatic technique. Hemostasis at the posterior mediastinum was performed successfully and quickly in all cases with this method, requiring up to four pieces of gauze for a complete hemostasis. Median required time for hemostasis was 1219 (range 1896 to 1293) seconds and estimated blood loss was 20.4 (range 15 to 25) ml during gauze packing. Conclusions Our technique could minimize bleeding after the removal of the thoracic esophagus. The gauze-packing method is a simple and easy technique for secure hemostasis when performing a transhiatal esophagectomy. PMID:23253358

Local, global, and nonlinear screening in twisted double-layer graphene

DOE PAGES

Lu, Chih -Pin; Rodriguez-Vega, Martin; Li, Guohong; ...

2016-06-02

One-atom-thick crystalline layers and their vertical heterostructures carry the promise of designer electronic materials that are unattainable by standard growth techniques. To realize their potential it is necessary to isolate them from environmental disturbances, in particular those introduced by the substrate. However, finding and characterizing suitable substrates, and minimizing the random potential fluctuations they introduce, has been a persistent challenge in this emerging field. In this paper, we show that Landau-level (LL) spectroscopy offers the unique capability to quantify both the reduction of the quasiparticles’ lifetime and the long-range inhomogeneity due to random potential fluctuations. Harnessing this technique together withmore » direct scanning tunneling microscopy and numerical simulations we demonstrate that the insertion of a graphene buffer layer with a large twist angle is a very effective method to shield a 2D system from substrate interference that has the additional desirable property of preserving the electronic structure of the system under study. Finally, we further show that owing to its remarkable nonlinear screening capability a single graphene buffer layer provides better shielding than either increasing the distance to the substrate or doubling the carrier density and reduces the amplitude of the potential fluctuations in graphene to values even lower than the ones in AB-stacked bilayer graphene.« less

Local, global, and nonlinear screening in twisted double-layer graphene

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

Lu, Chih -Pin; Rodriguez-Vega, Martin; Li, Guohong

One-atom-thick crystalline layers and their vertical heterostructures carry the promise of designer electronic materials that are unattainable by standard growth techniques. To realize their potential it is necessary to isolate them from environmental disturbances, in particular those introduced by the substrate. However, finding and characterizing suitable substrates, and minimizing the random potential fluctuations they introduce, has been a persistent challenge in this emerging field. In this paper, we show that Landau-level (LL) spectroscopy offers the unique capability to quantify both the reduction of the quasiparticles’ lifetime and the long-range inhomogeneity due to random potential fluctuations. Harnessing this technique together withmore » direct scanning tunneling microscopy and numerical simulations we demonstrate that the insertion of a graphene buffer layer with a large twist angle is a very effective method to shield a 2D system from substrate interference that has the additional desirable property of preserving the electronic structure of the system under study. Finally, we further show that owing to its remarkable nonlinear screening capability a single graphene buffer layer provides better shielding than either increasing the distance to the substrate or doubling the carrier density and reduces the amplitude of the potential fluctuations in graphene to values even lower than the ones in AB-stacked bilayer graphene.« less

Technology Insertion-Engineering Services Process Characterization Task Order No. 1. Book 2 of 3. Database Documentation Book. OO-ALC MANPGP (Wheels - WCD’S)

DTIC Science & Technology

1989-12-15

RElOVE MASKINE TAPE .00!91 .002 000 Al RCB-OH-W2 1.00 REMY WHL HLF F/PAINT CONVYOR .00833 .010 0040 E RWr- BBP -0 1.00 BALPOCE WEEL HALF .0773 .093 0050 5...16S601-819 16W6-35-3-2 15 ART SHE 160 PULTIPLE LA-10 L"L R/H AIM 9 1441--1-M -36A 7 472-M 1L--11. z.I-- PARK AN)E 161814, LEf-N sE. r& ffA t- 1450-00-. b

Computer output microfilm (FR80) systems software documentation, volume 2

NASA Technical Reports Server (NTRS)

1975-01-01

The system consists of a series of programs which convert digital data from magnetic tapes into alpha-numeric characters, graphic plots, and imagery that is recorded on the face of a cathode ray tube. A special camera photographs the face of the tube on microfilm for subsequent display on a film reader. The applicable documents which apply to this system are delineated. The functional relationship between the system software, the standard insert routines, and the applications programs is described; all the applications programs are described in detail. Instructions for locating those documents are presented along with test preparations sheets for all baseline and/or program modification acceptance tests.

The Twist Box Domain is Required for Twist1-induced Prostate Cancer Metastasis

PubMed Central

Gajula, Rajendra P.; Chettiar, Sivarajan T.; Williams, Russell D.; Thiyagarajan, Saravanan; Kato, Yoshinori; Aziz, Khaled; Wang, Ruoqi; Gandhi, Nishant; Wild, Aaron T.; Vesuna, Farhad; Ma, Jinfang; Salih, Tarek; Cades, Jessica; Fertig, Elana; Biswal, Shyam; Burns, Timothy F.; Chung, Christine H.; Rudin, Charles M.; Herman, Joseph M.; Hales, Russell K.; Raman, Venu; An, Steven S.; Tran, Phuoc T.

2013-01-01

Twist1, a basic helix-loop-helix transcription factor, plays a key role during development and is a master regulator of the epithelial-mesenchymal transition (EMT) that promotes cancer metastasis. Structure-function relationships of Twist1 to cancer-related phenotypes are underappreciated, so we studied the requirement of the conserved Twist box domain for metastatic phenotypes in prostate cancer (PCa). Evidence suggests that Twist1 is overexpressed in clinical specimens and correlated with aggressive/metastatic disease. Therefore, we examined a transactivation mutant, Twist1-F191G, in PCa cells using in vitro assays which mimic various stages of metastasis. Twist1 overexpression led to elevated cytoskeletal stiffness and cell traction forces at the migratory edge of cells based on biophysical single-cell measurements. Twist1 conferred additional cellular properties associated with cancer cell metastasis including increased migration, invasion, anoikis resistance, and anchorage-independent growth. The Twist box mutant was defective for these Twist1 phenotypes in vitro. Importantly, we observed a high frequency of Twist1-induced metastatic lung tumors and extra-thoracic metastases in vivo using the experimental lung metastasis assay. The Twist box was required for PCa cells to colonize metastatic lung lesions and extra-thoracic metastases. Comparative genomic profiling revealed transcriptional programs directed by the Twist box that were associated with cancer progression, such as Hoxa9. Mechanistically, Twist1 bound to the Hoxa9 promoter and positively regulated Hoxa9 expression in PCa cells. Finally, Hoxa9 was important for Twist1-induced cellular phenotypes associated with metastasis. These data suggest that the Twist box domain is required for Twist1 transcriptional programs and PCa metastasis. PMID:23982216

Copper link evaluations/solutions for fiber channel, SSA, SONET, ATM, and other services through 4 Gb/sec: basic information, test results, and evaluation

NASA Astrophysics Data System (ADS)

Leib, Michael J.

1995-10-01

Technitrol, the original designer of MIL-STD-1553 transformers, the original military 1Mb/s LAN, has advanced the state of the art one further notch, introducing a series of transceivers that allow high speed (through 1 Gb/s) data transmission over copper wire instead of fiber optic cable. One such device can be employed to implement the Fiber Channel Interface as defined by hte X3T11 ANSI Fibre Channel Committee using either mini coax, Type 1 shielded twisted pair, twinax or video cable. The technology now exists to upgrade data transmission rates on current physical media to speeds formerly only available with fiber optic cabling. Copper transceiver technology provides a cost effective alternative for dealing with demanding high speed applications such as high speed serial data transfer, high speed disk and tape storage transfer, imaging telemetry, radar, and other avionics applications. Eye diagrams will be presented to show that excellent data transmission at rates of 1 gigabit/sec with low jitter is capable over mini coax at distances to approximately 50 meters, shielded twisted pair and twinax cable to distances of 105 meters, and video cable to distances of 175 meters. Distances are further at lower data rates. As a member of the X3T11 ANSI Fiber Channel Committee, Technitrol has developed a Physical Media (copper wire) Dependant (PMD) transceiver not only compliant with the Fibre Channel Specifications but exceeding the specifications by a factor greater than four. Conceivably, this opens high speed interconnections for today's high data rate requirements to copper cabling systems. Fibre Optic problems need not be dealt with to obtain data transfers for high speed information transfers.

Is Supramolecular Filament Chirality the Underlying Cause of Major Morphology Differences in Amyloid Fibrils?

PubMed Central

2015-01-01

The unique enhanced sensitivity of vibrational circular dichroism (VCD) to the formation and development of amyloid fibrils in solution is extended to four additional fibril-forming proteins or peptides where it is shown that the sign of the fibril VCD pattern correlates with the sense of supramolecular filament chirality and, without exception, to the dominant fibril morphology as observed in AFM or SEM images. Previously for insulin, it has been demonstrated that the sign of the VCD band pattern from filament chirality can be controlled by adjusting the pH of the incubating solution, above pH 2 for “normal” left-hand-helical filaments and below pH 2 for “reversed” right-hand-helical filaments. From AFM or SEM images, left-helical filaments form multifilament braids of left-twisted fibrils while the right-helical filaments form parallel filament rows of fibrils with a flat tape-like morphology, the two major classes of fibril morphology that from deep UV resonance Raman scattering exhibit the same cross-β-core secondary structure. Here we investigate whether fibril supramolecular chirality is the underlying cause of the major morphology differences in all amyloid fibrils by showing that the morphology (twisted versus flat) of fibrils of lysozyme, apo-α-lactalbumin, HET-s (218–289) prion, and a short polypeptide fragment of transthyretin, TTR (105–115), directly correlates to their supramolecular chirality as revealed by VCD. The result is strong evidence that the chiral supramolecular organization of filaments is the principal underlying cause of the morphological heterogeneity of amyloid fibrils. Because fibril morphology is linked to cell toxicity, the chirality of amyloid aggregates should be explored in the widely used in vitro models of amyloid-associated diseases. PMID:24484302

Is supramolecular filament chirality the underlying cause of major morphology differences in amyloid fibrils?

PubMed

Kurouski, Dmitry; Lu, Xuefang; Popova, Ludmila; Wan, William; Shanmugasundaram, Maruda; Stubbs, Gerald; Dukor, Rina K; Lednev, Igor K; Nafie, Laurence A

2014-02-12

The unique enhanced sensitivity of vibrational circular dichroism (VCD) to the formation and development of amyloid fibrils in solution is extended to four additional fibril-forming proteins or peptides where it is shown that the sign of the fibril VCD pattern correlates with the sense of supramolecular filament chirality and, without exception, to the dominant fibril morphology as observed in AFM or SEM images. Previously for insulin, it has been demonstrated that the sign of the VCD band pattern from filament chirality can be controlled by adjusting the pH of the incubating solution, above pH 2 for "normal" left-hand-helical filaments and below pH 2 for "reversed" right-hand-helical filaments. From AFM or SEM images, left-helical filaments form multifilament braids of left-twisted fibrils while the right-helical filaments form parallel filament rows of fibrils with a flat tape-like morphology, the two major classes of fibril morphology that from deep UV resonance Raman scattering exhibit the same cross-β-core secondary structure. Here we investigate whether fibril supramolecular chirality is the underlying cause of the major morphology differences in all amyloid fibrils by showing that the morphology (twisted versus flat) of fibrils of lysozyme, apo-α-lactalbumin, HET-s (218-289) prion, and a short polypeptide fragment of transthyretin, TTR (105-115), directly correlates to their supramolecular chirality as revealed by VCD. The result is strong evidence that the chiral supramolecular organization of filaments is the principal underlying cause of the morphological heterogeneity of amyloid fibrils. Because fibril morphology is linked to cell toxicity, the chirality of amyloid aggregates should be explored in the widely used in vitro models of amyloid-associated diseases.

A strain-isolation design for stretchable electronics

NASA Astrophysics Data System (ADS)

Wu, Jian; Li, Ming; Chen, Wei-Qiu; Kim, Dae-Hyeong; Kim, Yun-Soung; Huang, Yong-Gang; Hwang, Keh-Chih; Kang, Zhan; Rogers, John A.

2010-12-01

Stretchable electronics represents a direction of recent development in next-generation semiconductor devices. Such systems have the potential to offer the performance of conventional wafer-based technologies, but they can be stretched like a rubber band, twisted like a rope, bent over a pencil, and folded like a piece of paper. Isolating the active devices from strains associated with such deformations is an important aspect of design. One strategy involves the shielding of the electronics from deformation of the substrate through insertion of a compliant adhesive layer. This paper establishes a simple, analytical model and validates the results by the finite element method. The results show that a relatively thick, compliant adhesive is effective to reduce the strain in the electronics, as is a relatively short film.

A possible regulatory link between Twist 1 and PPARγ gene regulation in 3T3-L1 adipocytes.

PubMed

Ren, Rui; Chen, Zhufeng; Zhao, Xia; Sun, Tao; Zhang, Yuchao; Chen, Jie; Lu, Sumei; Ma, Wanshan

2016-11-08

Peroxisome proliferator-activated receptor γ (PPARγ) is a critical gene that regulates the function of adipocytes. Therefore, studies on the molecular regulation mechanism of PPARγ are important to understand the function of adipose tissue. Twist 1 is another important functional gene in adipose tissue, and hundreds of genes are regulated by Twist 1. The aim of this study was to investigate the regulation of Twist 1 and PPARγ expression in 3T3-L1 mature adipocytes. We induced differentiation in 3T3-L1 preadipocytes and examined alterations in Twist 1 and PPARγ expression. We used the PPARγ agonist pioglitazone and the PPARγ antagonist T0070907 to investigate the effect of PPARγ on Twist 1 expression. In addition, we utilized retroviral interference and overexpression of Twist 1 to determine the effects of Twist 1 on PPARγ expression. The expression levels of Twist 1 and PPARγ were induced during differentiation in 3T3-L1 adipocytes. Application of either a PPARγ agonist (pioglitazone) or antagonist (T0070907) influenced Twist 1 expression, with up-regulation of Twist 1 under pioglitazone (1 μM, 24 h) and down-regulation of Twist 1 under T0070907 (100 μM, 24 h) exposure. Furthermore, the retroviral interference of Twist 1 decreased the protein and mRNA expression of PPARγ, while Twist 1 overexpression had the opposite effect. There was a possible regulatory link between Twist 1 and PPARγ in 3T3-L1 mature adipocytes. This regulatory link enhanced the regulation of PPARγ and may be a functional mechanism of Twist 1 regulation of adipocyte physiology and pathology.

Further analyses of laminar flow heat transfer in circular sector ducts

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

Lei, Q.M.; Trupp, A.C.

1989-11-01

Heat transfer in circular sector ducts is often encountered in multipassage tubes. Certain flow characteristics of circular sector ducts for apex angles up to {pi} have been determined as documented by Shah and London (1978). Recently, Lei and Trupp (1989) have more completely analyzed the flow characteristics of fully developed laminar flow for apex angles up to 2{pi}, including the location of the maximum velocity. Heat transfer results of fully developed laminar flow in circular sector ducts are also available for certain boundary conditions. Trupp and Lau (1984) numerically determined the average Nusselt number (Nu{sub T}) for isothermal walls. Eckertmore » et al. (1958) initially derived an analytical expression for the temperature profile for the case of H1. Sparrow and Haji-angles up to {pi}. However, the above work required numerical integration (or equivalent) to obtain a value for Nu{sub H1}. Regarding the H1{sub ad} boundary condition, Date (1974) numerically obtained a limiting value of Nu{sub H1}{sub ad} for the semicircular duct from the prediction of circular tubes containing a twisted tape (straight and nonconducting tape). Hong and Bergles (1976) also reported an asymptotic value of Nu{sub H1}{sub ad} for the semicircular duct from their entrance region solution. Otherwise it appears that there are no published analytical results of Nu{sub H1}{sub ad} for circular sector ducts. The purpose of this technical note is to communicate these results. In addition, a novel series expression for Nu{sub H1} is presented together with results for apex angles up to 2{pi}.« less

Ventriculostomy for acute hydrocephalus in critically ill patients on the ICU--outcome analysis of two different procedures.

PubMed

Schödel, Petra; Proescholdt, Martin; Brawanski, Alexander; Bele, Sylvia; Schebesch, Karl-Michael

2012-04-01

Burr-hole trephine and insertion of an external ventricular drainage (EVD) is a common procedure in neurosurgical practice. In critically ill patients, the transport to the operating room, OR represents a major risk. Thus, the burr-hole trephine and implantation of an EVD is frequently performed on the Intensive Care Unit (ICU). Since 2004, we have applied two different procedures: the conventional method with a mechanical compressed air or an electric drill, and an alternative method with a manual twist drill, including fixation of the EVD in a skull screw (Bolt Kit, Raumedic AG, Germany). This study was designed to evaluate the outcome of both surgical procedures. In this retrospective analysis we included 166 consecutive patients with acute hydrocephalus due to intracranial hemorrhage that had been operated at our neurosurgical ICU in a six years interval. We reviewed the charts for gender and age, kind of surgical procedure, cerebrospinal fluid (CSF)-infections, duration of drainage, attempts of insertions, wound infections, misplacement rate, post-surgical hemorrhages, revisions, comorbidities and shunt-dependency. In 122 patients we applied the Bolt Kit System, in 44 patients the conventional method was performed. We found a significantly lower rate of CSF-infections and significantly fewer attempts of insertions in the Bolt Kit group (p = 0.002 and p = 0.001, respectively). The rate of wound infections, misplacement, revisions, shunt-dependency and the post-surgical hemorrhages did not differ significantly. Our data indicate that the manual drill and the skull screw are safe and feasible tools in the treatment of acute hydrocephalus. Presumably, the direct skin contact is causative for the higher rate of CSF-infections when the conventional method is performed. The skull screw guides the EVD into the ventricle without skin contact. The lower number of insertions needed may be due to the fact that the skull screw allows just one trajectory for the insertion of the EVD.

Does a 4 diagram manual enable laypersons to operate the Laryngeal Mask Supreme®? A pilot study in the manikin.

PubMed

Schälte, Gereon; Stoppe, Christian; Rossaint, Rolf; Gilles, Laura; Heuser, Maike; Rex, Steffen; Coburn, Mark; Zoremba, Norbert; Rieg, Annette

2012-03-27

Bystander resuscitation plays an important role in lifesaving cardiopulmonary resuscitation (CPR). A significant reduction in the "no-flow-time", quantitatively better chest compressions and an improved quality of ventilation can be demonstrated during CPR using supraglottic airway devices (SADs). Previous studies have demonstrated the ability of inexperienced persons to operate SADs after brief instruction. The aim of this pilot study was to determine whether an instruction manual consisting of four diagrams enables laypersons to operate a Laryngeal Mask Supreme® (LMAS) in the manikin. An instruction manual of four illustrations with speech bubbles displaying the correct use of the LMAS was designed. Laypersons were handed a bag containing a LMAS, a bag mask valve device (BMV), a syringe prefilled with air and the instruction sheet, and were asked to perform and ventilate the manikin as displayed. Time to ventilation was recorded and degree of success evaluated. A total of 150 laypersons took part. Overall 145 participants (96.7%) inserted the LMAS in the manikin in the right direction. The device was inserted inverted or twisted in 13 (8.7%) attempts. Eight (5.3%) individuals recognized this and corrected the position. Within the first 2 minutes 119 (79.3%) applicants were able to insert the LMAS and provide tidal volumes greater than 150 ml (estimated dead space). Time to insertion and first ventilation was 83.2 ± 29 s. No significant difference related to previous BLS training (P = 0.85), technical education (P = 0.07) or gender could be demonstrated (P = 0.25). In manikin laypersons could insert LMAS in the correct direction after onsite instruction by a simple manual with a high success rate. This indicates some basic procedural understanding and intellectual transfer in principle. Operating errors (n = 91) were frequently not recognized and corrected (n = 77). Improvements in labeling and the quality of instructional photographs may reduce individual error and may optimize understanding.

Pelvic Floor 3D Ultrasound of Women with a TVT, TVT-O, or TVT-S for Stress Urinary Incontinence at the Three-year Follow-up.

PubMed

Rodrigues, Claudinei A; Bianchi-Ferraro, Ana Maria H M; Zucchi, Eliana Viana Monteiro; Sartori, Marair G F; Girão, Manoel J B C; Jarmy-Di Bella, Zsuzsanna I K

2017-09-01

Objective  Using three-dimensional ultrasound (3D-US), we aimed to compare the tape position and the angle formed by the sling arms in different techniques of mid-urethral sling insertion for the surgical treatment of stress urinary incontinence, three years after surgery. In addition, we examined the correlations between the US findings and the clinical late postoperative results. Methods  A prospective cross-sectional cohort study of 170 patients who underwent a sling procedure between May 2009 and December 2011 was performed. The final sample, with US images of sufficient quality, included 26 retropubic slings (tension-free vaginal tape, TVT), 42 transobturator slings (tension-free vaginal tape-obturator, TVT-O), and 37 single-incision slings (tension-free vaginal tape-Secur, TVT-S). The images (at rest, during the Valsalva maneuver, and during pelvic floor contraction) were analyzed offline by 2 different observers blinded against the surgical and urinary continence status. Group comparisons were performed using the Student t -test, the chi-squared and the Kruskal-Wallis tests, and analyses of variance with Tukey multiple comparisons. Results  Differences among the groups were found in the mean angle of the tape arms (TVT = 119.94°, TVT-O = 141.93°, TVT-S = 121.06°; p  < 0.001) and in the distance between the bladder neck and the tape at rest (TVT = 1.65 cm, TVT-O = 1.93 cm, TVT-S = 1.95 cm; p  = 0.010). The global objective cure rate was of 87.8% (TVT = 88.5%, TVT-O = 90.5%, TVT-S = 83.8%; p  = 0.701). The overall subjective cure rate was of 83.8% (TVT = 88.5%, TVT-O = 88.5% and TVT-S = 78.4%; p  = 0.514). The slings were located in the mid-urethra in 85.7% of the patients (TVT = 100%, TVT-O = 73.8%, TVT-S = 89.2%; p  = 0.001), with a more distal location associated with obesity (distal: 66.7% obese; mid-urethra: 34% obese; p  = 0.003). Urgency-related symptoms were observed in 23.8% of the patients (TVT = 30.8%, TVT-O = 21.4%, TVT-S = 21.6%; p  = 0.630). Conclusions  The angle formed by the arms of the sling tape was more obtuse for the transobturator slings compared with the angles for the retropubic or single-incision slings. Retropubic slings were more frequently located in the mid-urethra compared with the other slings, regardless of obesity. However, the analyzed sonographic measures did not correlate with the urinary symptoms three years after the surgery. Thieme Revinter Publicações Ltda Rio de Janeiro, Brazil.

Endothelial TWIST1 Promotes Pathological Ocular Angiogenesis

PubMed Central

Li, Jie; Liu, Chi-Hsiu; Sun, Ye; Gong, Yan; Fu, Zhongjie; Evans, Lucy P.; Tian, Katherine T.; Juan, Aimee M.; Hurst, Christian G.; Mammoto, Akiko; Chen, Jing

2014-01-01

Purpose. Pathological neovessel formation impacts many blinding vascular eye diseases. Identification of molecular signatures distinguishing pathological neovascularization from normal quiescent vessels is critical for developing new interventions. Twist-related protein 1 (TWIST1) is a transcription factor important in tumor and pulmonary angiogenesis. This study investigated the potential role of TWIST1 in modulating pathological ocular angiogenesis in mice. Methods. Twist1 expression and localization were analyzed in a mouse model of oxygen-induced retinopathy (OIR). Pathological ocular angiogenesis in Tie2-driven conditional Twist1 knockout mice were evaluated in both OIR and laser-induced choroidal neovascularization models. In addition, the effects of TWIST1 on angiogenesis and endothelial cell function were analyzed in sprouting assays of aortic rings and choroidal explants isolated from Twist1 knockout mice, and in human retinal microvascular endothelial cells treated with TWIST1 small interfering RNA (siRNA). Results. TWIST1 is highly enriched in pathological neovessels in OIR retinas. Conditional Tie2-driven depletion of Twist1 significantly suppressed pathological neovessels in OIR without impacting developmental retinal angiogenesis. In a laser-induced choroidal neovascularization model, Twist1 deficiency also resulted in significantly smaller lesions with decreased vascular leakage. In addition, loss of Twist1 significantly decreased vascular sprouting in both aortic ring and choroid explants. Knockdown of TWIST1 in endothelial cells led to dampened expression of vascular endothelial growth factor receptor 2 (VEGFR2) and decreased endothelial cell proliferation. Conclusions. Our study suggests that TWIST1 is a novel regulator of pathologic ocular angiogenesis and may represent a new molecular target for developing potential therapeutic treatments to suppress pathological neovascularization in vascular eye diseases. PMID:25414194

Phosphorylation of basic helix-loop-helix transcription factor Twist in development and disease.

PubMed

Xue, Gongda; Hemmings, Brian A

2012-02-01

The transcription factor Twist plays vital roles during embryonic development through regulating/controlling cell migration. However, postnatally, in normal physiological settings, Twist is either not expressed or inactivated. Increasing evidence shows a strong correlation between Twist reactivation and both cancer progression and malignancy, where the transcriptional activities of Twist support cancer cells to disseminate from primary tumours and subsequently establish a secondary tumour growth in distant organs. However, it is largely unclear how this signalling programme is reactivated or what signalling pathways regulate its activity. The present review discusses recent advances in Twist regulation and activity, with a focus on phosphorylation-dependent Twist activity, potential upstream kinases and the contribution of these factors in transducing biological signals from upstream signalling complexes. The recent advances in these areas have shed new light on how phosphorylation-dependent regulation of the Twist proteins promotes or suppresses Twist activity, leading to differential regulation of Twist transcriptional targets and thereby influencing cell fate.

Twist functions in vertebral column formation in medaka, Oryzias latipes.

PubMed

Yasutake, Junichi; Inohaya, Keiji; Kudo, Akira

2004-07-01

Medaka twist, a basic helix-loop-helix (bHLH) transcription factor, is expressed in the sclerotome during embryogenesis. We previously established a line of twist-EGFP transgenic medaka, whose EGFP expression is regulated by the twist promoter; therefore, we could observe the behavior of sclerotomal cells in vivo. In the transgenic medaka embryos, EGFP-positive sclerotomal cells migrated dorsally around the notochord and the neural tube, where at a later stage the vertebral column would be formed. This finding strongly suggests that twist-expressing sclerotomal cells participate in vertebral column formation in medaka. To clarify the function of twist gene in the sclerotome, we performed knockdown analysis of twist by using two kinds of morpholino antisense oligonucleotides targeted against twist (MO1 and MO2). Both the MO1 and MO2 morphants exhibited absence of neural arches, which are bilaterally paired, dorsomedially oriented bones on the dorsal aspect of the centrum. In addition, MO2, which blocks translation of only endogenous twist mRNA in the twist-EGFP transgenic medaka, did not affect the migration pattern of EGFP-positive cells, revealing that the migration of sclerotome-derived cells were normal in the absence of twist gene function. These results demonstrate that medaka twist functions in vertebral column formation by regulating the sclerotomal cell differentiation.

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

Casalbuoni, S., E-mail: sara.casalbuoni@kit.edu; Cecilia, A.; Gerstl, S.

Superconducting undulators (SCUs) have the potential to reach higher brilliance and flux with respect to the state of the art permanent magnet insertion devices. ANKA is collaborating with the industrial partner Babcock Noell GmbH (BNG) to realize NbTi conduction cooled planar devices for low emittance light sources, and is developing the instrumentation to characterize the magnetic field properties and to measure the beam heat load to a cold bore needed for the cryogenic design of SCUs. We present here: the most recent results obtained within the ANKA-BNG collaboration, the progress achieved in the development of the instrumentation, and the inmore » house studies on the application of high temperature superconducting (HTS) tape to the SCU technology.« less

Neurogenic bladder in spinal cord injury patients

PubMed Central

Taweel, Waleed Al; Seyam, Raouf

2015-01-01

Neurogenic bladder dysfunction due to spinal cord injury poses a significant threat to the well-being of patients. Incontinence, renal impairment, urinary tract infection, stones, and poor quality of life are some complications of this condition. The majority of patients will require management to ensure low pressure reservoir function of the bladder, complete emptying, and dryness. Management typically begins with anticholinergic medications and clean intermittent catheterization. Patients who fail this treatment because of inefficacy or intolerability are candidates for a spectrum of more invasive procedures. Endoscopic managements to relieve the bladder outlet resistance include sphincterotomy, botulinum toxin injection, and stent insertion. In contrast, patients with incompetent sphincters are candidates for transobturator tape insertion, sling surgery, or artificial sphincter implantation. Coordinated bladder emptying is possible with neuromodulation in selected patients. Bladder augmentation, usually with an intestinal segment, and urinary diversion are the last resort. Tissue engineering is promising in experimental settings; however, its role in clinical bladder management is still evolving. In this review, we summarize the current literature pertaining to the pathology and management of neurogenic bladder dysfunction in patients with spinal cord injury. PMID:26090342

Interdependence of pyrene interactions and tetramolecular G4-DNA assembly.

PubMed

Doluca, Osman; Withers, Jamie M; Loo, Trevor S; Edwards, Patrick J B; González, Carlos; Filichev, Vyacheslav V

2015-03-28

Controlling the arrangement of organic chromophores in supramolecular architectures is of primary importance for the development of novel functional molecules. Insertion of a twisted intercalating nucleic acid (TINA) moiety, containing phenylethynylpyren-1-yl derivatives, into a G-rich DNA sequence alters G-quadruplex folding, resulting in supramolecular structures with defined pyrene arrangements. Based on CD, NMR and ESI-mass-spectra, as well as TINA excited dimer (excimer) fluorescence emission we propose that insertion of the TINA monomer in the middle of a dTG4T sequence (i.e. dTGGXGGT, where X is TINA) converts a parallel tetramolecular G-quadruplex into an assembly composed of two identical antiparallel G-quadruplex subunits stacked via TINA-TINA interface. Kinetic analysis showed that TINA-TINA association controls complex formation in the presence of Na(+) but barely competes with guanine-mediated association in K(+) or in the sequence with the longer G-run (dTGGGXGGGT). These results demonstrate new perspectives in the design of molecular entities that can kinetically control G-quadruplex formation and show how tetramolecular G-quadruplexes can be used as a tuneable scaffold to control the arrangement of organic chromophores.

Role of left ventricular twist mechanics in cardiomyopathies, dance of the helices

PubMed Central

Kauer, Floris; Geleijnse, Marcel Leonard; van Dalen, Bastiaan Martijn

2015-01-01

Left ventricular twist is an essential part of left ventricular function. Nevertheless, knowledge is limited in “the cardiology community” as it comes to twist mechanics. Fortunately the development of speckle tracking echocardiography, allowing accurate, reproducible and rapid bedside assessment of left ventricular twist, has boosted the interest in this important mechanical aspect of left ventricular deformation. Although the fundamental physiological role of left ventricular twist is undisputable, the clinical relevance of assessment of left ventricular twist in cardiomyopathies still needs to be established. The fact remains; analysis of left ventricular twist mechanics has already provided substantial pathophysiological understanding on a comprehensive variety of cardiomyopathies. It has become clear that increased left ventricular twist in for example hypertrophic cardiomyopathy may be an early sign of subendocardial (microvascular) dysfunction. Furthermore, decreased left ventricular twist may be caused by left ventricular dilatation or an extensive myocardial scar. Finally, the detection of left ventricular rigid body rotation in noncompaction cardiomyopathy may provide an indispensible method to objectively confirm this difficult diagnosis. All this endorses the value of left ventricular twist in the field of cardiomyopathies and may further encourage the implementation of left ventricular twist parameters in the “diagnostic toolbox” for cardiomyopathies. PMID:26322187

Fast generation of three-dimensional computational boundary-conforming periodic grids of C-type. [for turbine blades and propellers

NASA Technical Reports Server (NTRS)

Dulikravich, D. S.

1982-01-01

A fast computer program, GRID3C, was developed to generate multilevel three dimensional, C type, periodic, boundary conforming grids for the calculation of realistic turbomachinery and propeller flow fields. The technique is based on two analytic functions that conformally map a cascade of semi-infinite slits to a cascade of doubly infinite strips on different Riemann sheets. Up to four consecutively refined three dimensional grids are automatically generated and permanently stored on four different computer tapes. Grid nonorthogonality is introduced by a separate coordinate shearing and stretching performed in each of three coordinate directions. The grids are easily clustered closer to the blade surface, the trailing and leading edges and the hub or shroud regions by changing appropriate input parameters. Hub and duct (or outer free boundary) have different axisymmetric shapes. A vortex sheet of arbitrary thickness emanating smoothly from the blade trailing edge is generated automatically by GRID3C. Blade cross sectional shape, chord length, twist angle, sweep angle, and dihedral angle can vary in an arbitrary smooth fashion in the spanwise direction.

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

Abdullayev, A. M.; Kulish, G. V.; Slyeptsov, O.

The evaluation of WWER-1000 Westinghouse fuel performance was done using the results of post–irradiation examinations of six LTAs and the WFA reload batches that have operated normally in mixed cores at South-Ukraine NPP, Unit-3 and Unit-2. The data on WFA/LTA elongation, FR growth and bow, WFA bow and twist, RCCA drag force and drag work, RCCA drop time, FR cladding integrity as well as the visual observation of fuel assemblies obtained during the 2006-2012 outages was utilized. The analysis of the measured data showed that assembly growth, FR bow, irradiation growth, and Zr-1%Nb grid and ZIRLO cladding corrosion lies withinmore » the design limits. The RCCA drop time measured for the LTA/WFA is about 1.9 s at BOC and practically does not change at EOC. The measured WFA bow and twist, and data of drag work on RCCA insertion showed that the WFA deformation in the mixed core is mostly controlled by the distortion of Russian FAs (TVSA) having the higher lateral stiffness. The visual inspection of WFAs carried out during the 2012 outages revealed some damage to the Zr-1%Nb grid outer strap for some WFAs during the loading sequence. The performed fundamental investigations allowed identifying the root cause of grid outer strap deformation and proposing the WFA design modifications for preventing damage to SG at a 225 kg handling trip limit.« less

Folding Elastic Thermal Surface - FETS

NASA Technical Reports Server (NTRS)

Urquiza, Eugenio; Zhang, Burt X.; Thelen, Michael P.; Rodriquez, Jose I.; Pellegrino, Sergio

2013-01-01

The FETS is a light and compact thermal surface (sun shade, IR thermal shield, cover, and/or deployable radiator) that is mounted on a set of offset tape-spring hinges. The thermal surface is constrained during launch and activated in space by a thermomechanical latch such as a wax actuator. An application-specific embodiment of this technology developed for the MATMOS (Mars Atmospheric Trace Molecule Occultation Spectrometer) project serves as a deployable cover and thermal shield for its passive cooler. The FETS fits compactly against the instrument within the constrained launch envelope, and then unfolds into a larger area once in space. In this application, the FETS protects the passive cooler from thermal damage and contamination during ground operations, launch, and during orbit insertion. Once unfolded or deployed, the FETS serves as a heat shield, intercepting parasitic heat loads by blocking the passive cooler s view of the warm spacecraft. The technology significantly enhances the capabilities of instruments requiring either active or passive cooling of optical detectors. This can be particularly important for instruments where performance is limited by the available radiator area. Examples would be IR optical instruments on CubeSATs or those launched as hosted payloads because radiator area is limited and views are often undesirable. As a deployable radiator, the panels making up the FETS are linked thermally by thermal straps and heat pipes; the structural support and deployment energy is provided using tape-spring hinges. The FETS is a novel combination of existing technologies. Prior art for deployable heat shields uses rotating hinges that typically must be lubricated to avoid cold welding or static friction. By using tape-spring hinges, the FETS avoids the need for lubricants by avoiding friction altogether. This also eliminates the potential for contamination of nearby cooled optics by outgassing lubricants. Furthermore, the tape-spring design of the FETS is also self-locking so the panels stay in a rigid and extended configuration after deployment. This unexpected benefit makes the tape-spring hinge design of the FETS a light, simple, reliable, compact, non-outgassing hinge, spring, and latch. While tape-spring hinges are not novel, they have never been used to deploy passive unfolding thermal surfaces (radiator panels, covers, sun shades, or IR thermal shields). Furthermore, because this technology is compact, it has minimal impact on the launch envelope and mass specifications. FETS enhances the performance of hosted payload instruments where the science data is limited by dark noise. Incorporating FETS into a thermal control system increases radiator area, which lowers the optical detector temperature. This results in higher SNR (signal-to-noise ratio) and improved science data.

The chopstick-noodle twist: an easy technique of percutaneous patellar fixation in minimally displaced patellar fractures.

PubMed

Muzaffar, Nasir; Ahmad, Nawaz; Ahmad, Aejaz; Ahmad, Nissar

2012-01-01

We report six cases of minimally displaced two-part patellar fractures with skin injury over the patella that were treated with percutaneous K wire fixation and compression applied using stainless steel (SS) wire. This technique makes it possible to perform early operative treatment in cases where unhealthy skin is not amenable to conventional tension band wiring. The technique employs two K wires inserted through the two fracture fragments under local or regional anaesthesia. They are then compressed using simple SS wire knots at the two ends - making it look like noodles at the end of two chopsticks. The fixation is subsequently augmented with a cylindrical plaster-of-Paris cast. The technique is simple, cheap and does not cause soft tissue injury.

Extension-twist coupling of composite circular tubes with application to tilt rotor blade design

NASA Technical Reports Server (NTRS)

Nixon, Mark W.

1987-01-01

This investigation was conducted to determine if twist deformation required for the design of full-scale extension-twist-coupled tilt-rotor blades can be achieved within material design limit loads, and to demonstrate the accuracy of a coupled-beam analysis in predicting twist deformations. Two extension-twist-coupled tilt-rotor blade designs were developed based on theoretically optimum aerodynamic twist distributions. The designs indicated a twist rate requirement of between .216 and .333 deg/in. Agreement between axial tests and analytical predictions was within 10 percent at design limit loads. Agreement between the torsion tests and predictions was within 11 percent.

The Twist Limit for Bipolar Active Regions

NASA Technical Reports Server (NTRS)

Moore, Ron; Falconer, David; Gary, Allen

2008-01-01

We present new evidence that further supports the standard idea that active regions are emerged magnetic-flux-rope omega loops. When the axial magnetic twist of a cylindrical flux rope exceeds a critical amount, the flux rope becomes unstable to kinking, and the excess axial twist is converted into writhe twist by the kinking. This suggests that, if active regions are emerged omega loops, then (1) no active region should have magnetic twist much above the limit set by kinking, (2) active regions having twist near the limit should often arise from kinked omega loops, and (3) since active regions having large delta sunspots are outstandingly twisted, these arise from kinked omega loops and should have twist near the limit for kinking. From each of 36 vector magnetograms of bipolar active regions, we have measured (1) the total flux of the vertical field above 100 G, (2) the area covered by this flux, and (3) the net electric current that arches over the polarity inversion line. These three quantities yield an estimate of the axial magnetic twist in a simple model cylindrical flux rope that corresponds to the top of the active region s hypothetical omega loop prior to emergence. In all 36 cases, the estimated twist is below the critical limit for kinking. The 11 most twisted active regions (1) have estimated twist within a factor of approx.3 of the limit, and (2) include all of our 6 active regions having large delta sunspots. Thus, our observed twist limit for bipolar active regions is in good accord with active regions being emerged omega loops.

Processing mechanics of alternate twist ply (ATP) yarn technology

NASA Astrophysics Data System (ADS)

Elkhamy, Donia Said

Ply yarns are important in many textile manufacturing processes and various applications. The primary process used for producing ply yarns is cabling. The speed of cabling is limited to about 35m/min. With the world's increasing demands of ply yarn supply, cabling is incompatible with today's demand activated manufacturing strategies. The Alternate Twist Ply (ATP) yarn technology is a relatively new process for producing ply yarns with improved productivity and flexibility. This technology involves self plying of twisted singles yarn to produce ply yarn. The ATP process can run more than ten times faster than cabling. To implement the ATP process to produce ply yarns there are major quality issues; uniform Twist Profile and yarn Twist Efficiency. The goal of this thesis is to improve these issues through process modeling based on understanding the physics and processing mechanics of the ATP yarn system. In our study we determine the main parameters that control the yarn twist profile. Process modeling of the yarn twist across different process zones was done. A computational model was designed to predict the process parameters required to achieve a square wave twist profile. Twist efficiency, a measure of yarn torsional stability and bulk, is determined by the ratio of ply yarn twist to singles yarn twist. Response Surface Methodology was used to develop the processing window that can reproduce ATP yarns with high twist efficiency. Equilibrium conditions of tensions and torques acting on the yarns at the self ply point were analyzed and determined the pathway for achieving higher twist efficiency. Mechanistic modeling relating equilibrium conditions to the twist efficiency was developed. A static tester was designed to zoom into the self ply zone of the ATP yarn. A computer controlled, prototypic ATP machine was constructed and confirmed the mechanistic model results. Optimum parameters achieving maximum twist efficiency were determined in this study. The successful results of this work have led to the filing of a US patent disclosing the method for producing ATP yarns with high yarn twist efficiency using a high convergence angle at the self ply point together with applying ply torque.

Genomic pathways modulated by Twist in breast cancer.

PubMed

Vesuna, Farhad; Bergman, Yehudit; Raman, Venu

2017-01-13

The basic helix-loop-helix transcription factor TWIST1 (Twist) is involved in embryonic cell lineage determination and mesodermal differentiation. There is evidence to indicate that Twist expression plays a role in breast tumor formation and metastasis, but the role of Twist in dysregulating pathways that drive the metastatic cascade is unclear. Moreover, many of the genes and pathways dysregulated by Twist in cell lines and mouse models have not been validated against data obtained from larger, independant datasets of breast cancer patients. We over-expressed the human Twist gene in non-metastatic MCF-7 breast cancer cells to generate the estrogen-independent metastatic breast cancer cell line MCF-7/Twist. These cells were inoculated in the mammary fat pad of female severe compromised immunodeficient mice, which subsequently formed xenograft tumors that metastasized to the lungs. Microarray data was collected from both in vitro (MCF-7 and MCF-7/Twist cell lines) and in vivo (primary tumors and lung metastases) models of Twist expression. Our data was compared to several gene datasets of various subtypes, classes, and grades of human breast cancers. Our data establishes a Twist over-expressing mouse model of breast cancer, which metastasizes to the lung and replicates some of the ontogeny of human breast cancer progression. Gene profiling data, following Twist expression, exhibited novel metastasis driver genes as well as cellular maintenance genes that were synonymous with the metastatic process. We demonstrated that the genes and pathways altered in the transgenic cell line and metastatic animal models parallel many of the dysregulated gene pathways observed in human breast cancers. Analogous gene expression patterns were observed in both in vitro and in vivo Twist preclinical models of breast cancer metastasis and breast cancer patient datasets supporting the functional role of Twist in promoting breast cancer metastasis. The data suggests that genetic dysregulation of Twist at the cellular level drives alterations in gene pathways in the Twist metastatic mouse model which are comparable to changes seen in human breast cancers. Lastly, we have identified novel genes and pathways that could be further investigated as targets for drugs to treat metastatic breast cancer.

Characterization of sequences in human TWIST required for nuclear localization

PubMed Central

Singh, Shalini; Gramolini, Anthony O

2009-01-01

Background Twist is a transcription factor that plays an important role in proliferation and tumorigenesis. Twist is a nuclear protein that regulates a variety of cellular functions controlled by protein-protein interactions and gene transcription events. The focus of this study was to characterize putative nuclear localization signals (NLSs) 37RKRR40 and 73KRGKK77 in the human TWIST (H-TWIST) protein. Results Using site-specific mutagenesis and immunofluorescences, we observed that altered TWISTNLS1 K38R, TWISTNLS2 K73R and K77R constructs inhibit nuclear accumulation of H-TWIST in mammalian cells, while TWISTNLS2 K76R expression was un-affected and retained to the nucleus. Subsequently, co-transfection of TWIST mutants K38R, K73R and K77R with E12 formed heterodimers and restored nuclear localization despite the NLSs mutations. Using a yeast-two-hybrid assay, we identified a novel TWIST-interacting candidate TCF-4, a basic helix-loop-helix transcription factor. The interaction of TWIST with TCF-4 confirmed using NLS rescue assays, where nuclear expression of mutant TWISTNLS1 with co-transfixed TCF-4 was observed. The interaction of TWIST with TCF-4 was also seen using standard immunoprecipitation assays. Conclusion Our study demonstrates the presence of two putative NLS motifs in H-TWIST and suggests that these NLS sequences are functional. Furthermore, we identified and confirmed the interaction of TWIST with a novel protein candidate TCF-4. PMID:19534813

Teaching Spatial Awareness for Better Twisting Somersaults.

ERIC Educational Resources Information Center

Hennessy, Jeff T.

1985-01-01

The barani (front somersault with one-half twist) and the back somersault with one twist are basic foundation skills necessary for more advanced twisting maneuvers. Descriptions of these movements on a trampoline surface are offered. (DF)

Metastasis-associated in colon cancer-1 promotes vasculogenic mimicry in gastric cancer by upregulating TWIST1/2

PubMed Central

Wang, Lin; Lin, Li; Chen, Xi; Sun, Li; Liao, Yulin; Huang, Na; Liao, Wangjun

2015-01-01

Vasculogenic mimicry (VM) is a blood supply modality that is strongly associated with the epithelial-mesenchymal transition (EMT), TWIST1 activation and tumor progression. We previously reported that metastasis-associated in colon cancer-1 (MACC1) induced the EMT and was associated with a poor prognosis of patients with gastric cancer (GC), but it remains unknown whether MACC1 promotes VM and regulates the TWIST signaling pathway in GC. In this study, we investigated MACC1 expression and VM by immunohistochemistry in 88 patients with stage IV GC, and also investigated the role of TWIST1 and TWIST2 in MACC1-induced VM by using nude mice with GC xenografts and GC cell lines. We found that the VM density was significantly increased in the tumors of patients who died of GC and was positively correlated with MACC1 immunoreactivity (p < 0.05). The 3-year survival rate was only 8.6% in patients whose tumors showed double positive staining for MACC1 and VM, whereas it was 41.7% in patients whose tumors were negative for both MACC1 and VM. Moreover, nuclear expression of MACC1, TWIST1, and TWIST2 was upregulated in GC tissues compared with matched adjacent non-tumorous tissues (p < 0.05). Overexpression of MACC1 increased TWIST1/2 expression and induced typical VM in the GC xenografts of nude mice and in GC cell lines. MACC1 enhanced TWIST1/2 promoter activity and facilitated VM, while silencing of TWIST1 or TWIST2 inhibited VM. Hepatocyte growth factor (HGF) increased the nuclear translocation of MACC1, TWIST1, and TWIST2, while a c-Met inhibitor reduced these effects. These findings indicate that MACC1 promotes VM in GC by regulating the HGF/c-Met-TWIST1/2 signaling pathway, which means that MACC1 and this pathway are potential new therapeutic targets for GC. PMID:25895023

Real-Space Imaging of the Tailored Plasmons in Twisted Bilayer Graphene

NASA Astrophysics Data System (ADS)

Hu, F.; Das, Suprem R.; Luan, Y.; Chung, T.-F.; Chen, Y. P.; Fei, Z.

2017-12-01

We report a systematic plasmonic study of twisted bilayer graphene (TBLG)—two graphene layers stacked with a twist angle. Through real-space nanoimaging of TBLG single crystals with a wide distribution of twist angles, we find that TBLG supports confined infrared plasmons that are sensitively dependent on the twist angle. At small twist angles, TBLG has a plasmon wavelength comparable to that of single-layer graphene. At larger twist angles, the plasmon wavelength of TBLG increases significantly with apparently lower damping. Further analysis and modeling indicate that the observed twist-angle dependence of TBLG plasmons in the Dirac linear regime is mainly due to the Fermi-velocity renormalization, a direct consequence of interlayer electronic coupling. Our work unveils the tailored plasmonic characteristics of TBLG and deepens our understanding of the intriguing nano-optical physics in novel van der Waals coupled two-dimensional materials.

Real-Space Imaging of the Tailored Plasmons in Twisted Bilayer Graphene

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

Hu, F.; Das, Suprem R.; Luan, Y.

Here, we report a systematic plasmonic study of twisted bilayer graphene (TBLG)—two graphene layers stacked with a twist angle. Through real-space nanoimaging of TBLG single crystals with a wide distribution of twist angles, we find that TBLG supports confined infrared plasmons that are sensitively dependent on the twist angle. At small twist angles, TBLG has a plasmon wavelength comparable to that of single-layer graphene. At larger twist angles, the plasmon wavelength of TBLG increases significantly with apparently lower damping. Further analysis and modeling indicate that the observed twist-angle dependence of TBLG plasmons in the Dirac linear regime is mainly duemore » to the Fermi-velocity renormalization, a direct consequence of interlayer electronic coupling. Our work unveils the tailored plasmonic characteristics of TBLG and deepens our understanding of the intriguing nano-optical physics in novel van der Waals coupled two-dimensional materials.« less

Hydrogen bonds and twist in cellulose microfibrils.

PubMed

Kannam, Sridhar Kumar; Oehme, Daniel P; Doblin, Monika S; Gidley, Michael J; Bacic, Antony; Downton, Matthew T

2017-11-01

There is increasing experimental and computational evidence that cellulose microfibrils can exist in a stable twisted form. In this study, atomistic molecular dynamics (MD) simulations are performed to investigate the importance of intrachain hydrogen bonds on the twist in cellulose microfibrils. We systematically enforce or block the formation of these intrachain hydrogen bonds by either constraining dihedral angles or manipulating charges. For the majority of simulations a consistent right handed twist is observed. The exceptions are two sets of simulations that block the O2-O6' intrachain hydrogen bond, where no consistent twist is observed in multiple independent simulations suggesting that the O2-O6' hydrogen bond can drive twist. However, in a further simulation where exocyclic group rotation is also blocked, right-handed twist still develops suggesting that intrachain hydrogen bonds are not necessary to drive twist in cellulose microfibrils. Copyright © 2017 Elsevier Ltd. All rights reserved.

Real-Space Imaging of the Tailored Plasmons in Twisted Bilayer Graphene

DOE PAGES

Hu, F.; Das, Suprem R.; Luan, Y.; ...

2017-12-13

Here, we report a systematic plasmonic study of twisted bilayer graphene (TBLG)—two graphene layers stacked with a twist angle. Through real-space nanoimaging of TBLG single crystals with a wide distribution of twist angles, we find that TBLG supports confined infrared plasmons that are sensitively dependent on the twist angle. At small twist angles, TBLG has a plasmon wavelength comparable to that of single-layer graphene. At larger twist angles, the plasmon wavelength of TBLG increases significantly with apparently lower damping. Further analysis and modeling indicate that the observed twist-angle dependence of TBLG plasmons in the Dirac linear regime is mainly duemore » to the Fermi-velocity renormalization, a direct consequence of interlayer electronic coupling. Our work unveils the tailored plasmonic characteristics of TBLG and deepens our understanding of the intriguing nano-optical physics in novel van der Waals coupled two-dimensional materials.« less

Gauge transformations for twisted spectral triples

NASA Astrophysics Data System (ADS)

Landi, Giovanni; Martinetti, Pierre

2018-05-01

It is extended to twisted spectral triples the fluctuations of the metric as bounded perturbations of the Dirac operator that arises when a spectral triple is exported between Morita equivalent algebras, as well as gauge transformations which are obtained by the action of the unitary endomorphisms of the module implementing the Morita equivalence. It is firstly shown that the twisted-gauged Dirac operators, previously introduced to generate an extra scalar field in the spectral description of the standard model of elementary particles, in fact follow from Morita equivalence between twisted spectral triples. The law of transformation of the gauge potentials turns out to be twisted in a natural way. In contrast with the non-twisted case, twisted fluctuations do not necessarily preserve the self-adjointness of the Dirac operator. For a self-Morita equivalence, conditions are obtained in order to maintain self-adjointness that are solved explicitly for the minimal twist of a Riemannian manifold.

Study of nonlinear MHD equations governing the wave propagation in twisted coronal loops

NASA Technical Reports Server (NTRS)

Parhi, S.; DeBruyne, P.; Goossens, M.; Zhelyazkov, I.

1995-01-01

The solar corona, modelled by a low beta, resistive plasma slab, sustains MHD wave propagations due to shearing footpoint motions in the photosphere. By using a numerical algorithm the excitation and nonlinear development of MHD waves in twisted coronal loops are studied. The plasma responds to the footpoint motion by sausage waves if there is no twist. The twist in the magnetic field of the loop destroys initially developed sausage-like wave modes and they become kinks. The transition from sausage to kink modes is analyzed. The twist brings about mode degradation producing high harmonics and this generates more complex fine structures. This can be attributed to several local extrema in the perturbed velocity profiles. The Alfven wave produces remnants of the ideal 1/x singularity both for zero and non-zero twist and this pseudo-singularity becomes less pronounced for larger twist. The effect of nonlinearity is clearly observed by changing the amplitude of the driver by one order of magnitude. The magnetosonic waves also exhibit smoothed remnants of ideal logarithmic singularities when the frequency of the driver is correctly chosen. This pseudo-singularity for fast waves is absent when the coronal loop does not undergo any twist but becomes pronounced when twist is included. On the contrary, it is observed for slow waves even if there is no twist. Increasing the twist leads to a higher heating rate of the loop. The larger twist shifts somewhat uniformly distributed heating to layers inside the slab corresponding to peaks in the magnetic field strength.

Twist promotes tumor metastasis in basal-like breast cancer by transcriptionally upregulating ROR1.

PubMed

Cao, Jingying; Wang, Xin; Dai, Tao; Wu, Yuanzhong; Zhang, Meifang; Cao, Renxian; Zhang, Ruhua; Wang, Gang; Jiang, Rou; Zhou, Binhua P; Shi, Jian; Kang, Tiebang

2018-01-01

Rationale: Twist is a key transcription factor for induction of epithelial-mesenchymal transition (EMT), which promotes cell migration, invasion, and cancer metastasis, confers cancer cells with stem cell-like characteristics, and provides therapeutic resistance. However, the functional roles and targeted genes of Twist in EMT and cancer progression remain elusive. Methods: The potential targeted genes of Twist were identified from the global transcriptomes of T47D/Twist cells by microarray analysis. EMT phenotype was detected by western blotting and immunofluorescence of marker proteins. The dual-luciferase reporter and chromatin immunoprecipitation assays were employed to observe the direct transcriptional induction of ROR1 by Twist. A lung metastasis model was used to study the pro-metastatic role of Twist and ROR1 by injecting MDA-MB-231 cells into tail vein of nude mice. Bio-informatics analysis was utilized to measure the metastasis-free survival of breast cancer patients. Results: Twist protein was proved to directly activate the transcription of ROR1 gene, a receptor of Wnt5a in non-canonical WNT signaling pathway. Silencing of ROR1 inhibited EMT process, cell migration, invasion, and cancer metastasis of basal-like breast cancer (BLBC) cells. Knockdown of ROR1 also ameliorated the pro-metastatic effect of Twist. Furthermore, analyses of clinical specimens indicated that high expression of both ROR1 and Twist tightly correlates with poor metastasis-free survival of breast cancer patients. Conclusion: ROR1 is a targeted gene of Twist. Twist/ROR1 signaling is critical for invasion and metastasis of BLBC cells.

Twist for Snyder space

NASA Astrophysics Data System (ADS)

Meljanac, Daniel; Meljanac, Stjepan; Mignemi, Salvatore; Pikutić, Danijel; Štrajn, Rina

2018-03-01

We construct the twist operator for the Snyder space. Our starting point is a non-associative star product related to a Hermitian realisation of the noncommutative coordinates originally introduced by Snyder. The corresponding coproduct of momenta is non-coassociative. The twist is constructed using a general definition of the star product in terms of a bi-differential operator in the Hopf algebroid approach. The result is given by a closed analytical expression. We prove that this twist reproduces the correct coproducts of the momenta and the Lorentz generators. The twisted Poincaré symmetry is described by a non-associative Hopf algebra, while the twisted Lorentz symmetry is described by the undeformed Hopf algebra. This new twist might be important in the construction of different types of field theories on Snyder space.

Effect of twist on single-mode fiber-optic 3 × 3 couplers

NASA Astrophysics Data System (ADS)

Chen, Dandan; Ji, Minning; Peng, Lei

2018-01-01

In the fabricating process of a 3 × 3 fused tapered coupler, the three fibers are usually twisted to be close-contact. The effect of twist on 3 × 3 fused tapered couplers is investigated in this paper. It is found that though a linear 3 × 3 coupler may realize equal power splitting ratio theoretically by twisting a special angle, it is hard to be fabricated actually because the twist angle and the coupler's length must be determined in advance. While an equilateral 3 × 3 coupler can not only realize approximate equal power splitting ratio theoretically but can also be fabricated just by controlling the elongation length. The effect of twist on the equilateral 3 × 3 coupler lies in the relationship between the equal ratio error and the twist angle. The more the twist angle is, the larger the equal ratio error may be. The twist angle usually should be no larger than 90° on one coupling period length in order to keep the equal ratio error small enough. The simulation results agree well with the experimental data.

Technique for recovery of voice data from heat damaged magnetic tape

NASA Technical Reports Server (NTRS)

Melugin, J. F.; Obrien, D. E., III (Inventor)

1974-01-01

A method for conditioning, and thus enabling retrieval of intelligence from, magnetic tapes after damage from heat has caused the tape to wrinkle and curl severely thereby reducing tape width to less than one-half its original size. The damaged tape is superposed on a first piece of splicing tape with the oxide side of the magnetic tape in contact with the adhesive side of the splicing tape and then carefully smoothed by a special tool. A second piece of splicing tape is placed on the backing side of the magnetic tape then the resulting tape stack is trimmed to the original width of the magnetic tape. After the first piece of splicing tape is carefully removed from the oxide side of the damaged magnetic tape, the resulting magnetic tape is then ready to be placed into a recorder for playback.

Self-tapping ability of carbon fibre reinforced polyetheretherketone suture anchors.

PubMed

Feerick, Emer M; Wilson, Joanne; Jarman-Smith, Marcus; Ó'Brádaigh, Conchur M; McGarry, J Patrick

2014-10-01

An experimental and computational investigation of the self-tapping ability of carbon fibre reinforced polyetheretherketone (CFR-PEEK) has been conducted. Six CFR-PEEK suture anchor designs were investigated using PEEK-OPTIMA® Reinforced, a medical grade of CFR-PEEK. Experimental tests were conducted to investigate the maximum axial force and torque required for self-taping insertion of each anchor design. Additional experimental tests were conducted for some anchor designs using pilot holes. Computational simulations were conducted to determine the maximum stress in each anchor design at various stages of insertion. Simulations also were performed to investigate the effect of wall thickness in the anchor head. The maximum axial force required to insert a self-tapping CFR-PEEK suture anchor did not exceed 150 N for any anchor design. The maximum torque required to insert a self-tapping CFR-PEEK suture anchor did not exceed 0.8 Nm. Computational simulations reveal significant stress concentrations in the region of the anchor tip, demonstrating that a re-design of the tip geometry should be performed to avoid fracture during self-tapping, as observed in the experimental component of this study. This study demonstrates the ability of PEEK-OPTIMA Reinforced suture anchors to self-tap polyurethane foam bone analogue. This provides motivation to further investigate the self-tapping ability of CFR-PEEK suture anchors in animal/cadaveric bone. An optimised design for CFR-PEEK suture anchors offers the advantages of radiolucency, and mechanical properties similar to bone with the ability to self-tap. This may have positive implications for reducing surgery times and the associated costs with the procedure. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

A biomechanical comparison of 2 transosseous-equivalent double-row rotator cuff repair techniques using bioabsorbable anchors: cyclic loading and failure behavior.

PubMed

Spang, Jeffrey T; Buchmann, Stefan; Brucker, Peter U; Kouloumentas, Panos; Obst, Tobias; Schröder, Manuel; Burgkart, Rainer; Imhoff, Andreas B

2009-08-01

A novel double-row configuration was compared with a traditional double-row configuration for rotator cuff repair. In 10 matched-pair sheep shoulders in vitro repair was performed with either a double-row technique with corkscrew suture anchors for the medial row and insertion anchors for the lateral row (group A) or a double-row technique with a new tape-like suture material with insertion anchors for both the medial and lateral rows (group B). Each specimen underwent cyclic loading from 10 to 150 N for 100 cycles, followed by unidirectional failure testing. Gap formation and strain within the repair area for the first and last cycles were analyzed with a video digitizing system, and stiffness and failure load were determined from the load-elongation curve. The results were similar for the 2 repair types. There was no significant difference between the ultimate failure loads of the 2 techniques (421 +/- 150 N in group A and 408 +/- 66 N in group B, P = .31) or the stiffness of the 2 techniques (84 +/- 26 N/mm in group A and 99 +/- 20 N/mm in group B, P = .07). In addition, gap formation was not different between the repair types. Strain over the repair area was also not different between the repair types. Both tested rotator cuff repair techniques had high failure loads, limited gap formation, and acceptable strain patterns. No significant difference was found between the novel and conventional double-row repair types. Two double-row techniques-one with corkscrew suture anchors for the medial row and insertion anchors for the lateral row and one with insertion anchors for both the medial and lateral rows-provided excellent biomechanical profiles at time 0 for double-row repairs in a sheep model. Although the sheep model may not directly correspond to in vivo conditions, all-insertion anchor double-row constructs are worthy of further investigation.

Twisted supersymmetry: Twisted symmetry versus renormalizability

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

Dimitrijevic, Marija; Nikolic, Biljana; Radovanovic, Voja

We discuss a deformation of superspace based on a Hermitian twist. The twist implies a *-product that is noncommutative, Hermitian and finite when expanded in a power series of the deformation parameter. The Leibniz rule for the twisted supersymmetry transformations is deformed. A minimal deformation of the Wess-Zumino action is proposed and its renormalizability properties are discussed. There is no tadpole contribution, but the two-point function diverges. We speculate that the deformed Leibniz rule, or more generally the twisted symmetry, interferes with renormalizability properties of the model. We discuss different possibilities to render a renormalizable model.

Twist limits for late twisting double somersaults on trampoline.

PubMed

Yeadon, M R; Hiley, M J

2017-06-14

An angle-driven computer simulation model of aerial movement was used to determine the maximum amount of twist that could be produced in the second somersault of a double somersault on trampoline using asymmetrical movements of the arms and hips. Lower bounds were placed on the durations of arm and hip angle changes based on performances of a world trampoline champion whose inertia parameters were used in the simulations. The limiting movements were identified as the largest possible odd number of half twists for forward somersaulting takeoffs and even number of half twists for backward takeoffs. Simulations of these two limiting movements were found using simulated annealing optimisation to produce the required amounts of somersault, tilt and twist at landing after a flight time of 2.0s. Additional optimisations were then run to seek solutions with the arms less adducted during the twisting phase. It was found that 3½ twists could be produced in the second somersault of a forward piked double somersault with arms abducted 8° from full adduction during the twisting phase and that three twists could be produced in the second somersault of a backward straight double somersault with arms fully adducted to the body. These two movements are at the limits of performance for elite trampolinists. Copyright © 2017 Elsevier Ltd. All rights reserved.

Knockdown of TWIST1 enhances arsenic trioxide- and ionizing radiation-induced cell death in lung cancer cells by promoting mitochondrial dysfunction

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

Seo, Sung-Keum; Kim, Jae-Hee; Choi, Ha-Na

Highlights: • Knockdown of TWIST1 enhanced ATO- and IR-induced cell death in NSCLCs. • Intracellular ROS levels were increased in cells treated with TWIST1 siRNA. • TWIST1 siRNA induced MMP loss and mitochondrial fragmentation. • TWIST1 siRNA upregulated the fission-related proteins FIS1 and DRP1. - Abstract: TWIST1 is implicated in the process of epithelial mesenchymal transition, metastasis, stemness, and drug resistance in cancer cells, and therefore is a potential target for cancer therapy. In the present study, we found that knockdown of TWIST1 by small interfering RNA (siRNA) enhanced arsenic trioxide (ATO)- and ionizing radiation (IR)-induced cell death in non-small-cellmore » lung cancer cells. Interestingly, intracellular reactive oxygen species levels were increased in cells treated with TWIST1 siRNA and further increased by co-treatment with ATO or IR. Pretreatment of lung cancer cells with the antioxidant N-acetyl-cysteine markedly suppressed the cell death induced by combined treatment with TWIST1 siRNA and ATO or IR. Moreover, treatment of cells with TWIST1 siRNA induced mitochondrial membrane depolarization and significantly increased mitochondrial fragmentation (fission) and upregulated the fission-related proteins FIS1 and DRP1. Collectively, our results demonstrate that siRNA-mediated TWIST1 knockdown induces mitochondrial dysfunction and enhances IR- and ATO-induced cell death in lung cancer cells.« less

TWIST1-WDR5-Hottip regulates Hoxa9 chromatin to facilitate prostate cancer metastasis

PubMed Central

Malek, Reem; Gajula, Rajendra P.; Williams, Russell D.; Nghiem, Belinda; Simons, Brian W.; Nugent, Katriana; Wang, Hailun; Taparra, Kekoa; Lemtiri-Chlieh, Ghali; Yoon, Arum R.; True, Lawrence; An, Steven S.; DeWeese, Theodore L.; Ross, Ashley E.; Schaeffer, Edward M.; Pienta, Kenneth J.; Hurley, Paula J.; Morrissey, Colm; Tran, Phuoc T.

2017-01-01

TWIST1 is a transcription factor critical for development which can promote prostate cancer metastasis. During embryonic development, TWIST1 and HOXA9 are co-expressed in mouse prostate and then silenced post-natally. Here we report that TWIST1 and HOXA9 co-expression are re-activated in mouse and human primary prostate tumors and are further enriched in human metastases, correlating with survival. TWIST1 formed a complex with WDR5 and the lncRNA Hottip/HOTTIP, members of the MLL/COMPASS-like H3K4 methylases, which regulate chromatin in the Hox/HOX cluster during development. TWIST1 overexpression led to co-enrichment of TWIST1 and WDR5 as well increased H3K4me3 chromatin at the Hoxa9/HOXA9 promoter which was dependent on WDR5. Expression of WDR5 and Hottip/HOTTIP was also required for TWIST1-induced upregulation of HOXA9 and aggressive cellular phenotypes such as invasion and migration. Pharmacological inhibition of HOXA9 prevented TWIST1-induced aggressive prostate cancer cellular phenotypes in vitro and metastasis in vivo. This study demonstrates a novel mechanism by which TWIST1 regulates chromatin and gene expression by cooperating with the COMPASS-like complex to increase H3K4 trimethylation at target gene promoters. Our findings highlight a TWIST1-HOXA9 embryonic prostate developmental program that is reactivated during prostate cancer metastasis and is therapeutically targetable. PMID:28484075

Twist1 Suppresses Senescence Programs and Thereby Accelerates and Maintains Mutant Kras-Induced Lung Tumorigenesis

PubMed Central

Thiyagarajan, Saravanan; Das, Sandhya T.; Zabuawala, Tahera; Chen, Joy; Cho, Yoon-Jae; Luong, Richard; Tamayo, Pablo; Salih, Tarek; Aziz, Khaled; Adam, Stacey J.; Vicent, Silvestre; Nielsen, Carsten H.; Withofs, Nadia; Sweet-Cordero, Alejandro; Gambhir, Sanjiv S.; Rudin, Charles M.; Felsher, Dean W.

2012-01-01

KRAS mutant lung cancers are generally refractory to chemotherapy as well targeted agents. To date, the identification of drugs to therapeutically inhibit K-RAS have been unsuccessful, suggesting that other approaches are required. We demonstrate in both a novel transgenic mutant Kras lung cancer mouse model and in human lung tumors that the inhibition of Twist1 restores a senescence program inducing the loss of a neoplastic phenotype. The Twist1 gene encodes for a transcription factor that is essential during embryogenesis. Twist1 has been suggested to play an important role during tumor progression. However, there is no in vivo evidence that Twist1 plays a role in autochthonous tumorigenesis. Through two novel transgenic mouse models, we show that Twist1 cooperates with KrasG12D to markedly accelerate lung tumorigenesis by abrogating cellular senescence programs and promoting the progression from benign adenomas to adenocarcinomas. Moreover, the suppression of Twist1 to physiological levels is sufficient to cause Kras mutant lung tumors to undergo senescence and lose their neoplastic features. Finally, we analyzed more than 500 human tumors to demonstrate that TWIST1 is frequently overexpressed in primary human lung tumors. The suppression of TWIST1 in human lung cancer cells also induced cellular senescence. Hence, TWIST1 is a critical regulator of cellular senescence programs, and the suppression of TWIST1 in human tumors may be an effective example of pro-senescence therapy. PMID:22654667

Transverse kink oscillations in the presence of twist

NASA Astrophysics Data System (ADS)

Terradas, J.; Goossens, M.

2012-12-01

Context. Magnetic twist is thought to play an important role in coronal loops. The effects of magnetic twist on stable magnetohydrodynamic (MHD) waves is poorly understood because they are seldom studied for relevant cases. Aims: The goal of this work is to study the fingerprints of magnetic twist on stable transverse kink oscillations. Methods: We numerically calculated the eigenmodes of propagating and standing MHD waves for a model of a loop with magnetic twist. The azimuthal component of the magnetic field was assumed to be small in comparison to the longitudinal component. We did not consider resonantly damped modes or kink instabilities in our analysis. Results: For a nonconstant twist the frequencies of the MHD wave modes are split, which has important consequences for standing waves. This is different from the degenerated situation for equilibrium models with constant twist, which are characterised by an azimuthal component of the magnetic field that linearly increases with the radial coordinate. Conclusions: In the presence of twist standing kink solutions are characterised by a change in polarisation of the transverse displacement along the tube. For weak twist, and in the thin tube approximation, the frequency of standing modes is unaltered and the tube oscillates at the kink speed of the corresponding straight tube. The change in polarisation is linearly proportional to the degree of twist. This has implications with regard to observations of kink modes, since the detection of this variation in polarisation can be used as an indirect method to estimate the twist in oscillating loops.

Modeling and control of active twist aircraft

NASA Astrophysics Data System (ADS)

Cramer, Nicholas Bryan

The Wright Brothers marked the beginning of powered flight in 1903 using an active twist mechanism as their means of controlling roll. As time passed due to advances in other technologies that transformed aviation the active twist mechanism was no longer used. With the recent advances in material science and manufacturability, the possibility of the practical use of active twist technologies has emerged. In this dissertation, the advantages and disadvantages of active twist techniques are investigated through the development of an aeroelastic modeling method intended for informing the designs of such technologies and wind tunnel testing to confirm the capabilities of the active twist technologies and validate the model. Control principles for the enabling structural technologies are also proposed while the potential gains of dynamic, active twist are analyzed.

Anderson transition in a multiply-twisted helix.

PubMed

Ugajin, R

2001-06-01

We investigated the Anderson transition in a multiply-twisted helix in which a helical chain of components, i.e., atoms or nanoclusters, is twisted to produce a doubly-twisted helix, which itself can be twisted to produce a triply-twisted helix, and so on, in which there are couplings between adjacent rounds of helices. As the strength of the on-site random potentials increases, an Anderson transition occurs, suggesting that the number of dimensions is 3 for electrons running along the multiply-twisted helix when the couplings between adjacent rounds are strong enough. If the couplings are weakened, the dimensionality becomes less, resulting in localization of electrons. The effect of random connections between adjacent rounds of helices and random magnetic fields that thread the structure is analyzed using the spectral statistics of a quantum particle.

Association between Twist and multidrug resistance gene-associated proteins in Taxol®-resistant MCF-7 cells and a 293 cell model of Twist overexpression.

PubMed

Wang, Li; Tan, Rui-Zhi; Zhang, Zhi-Xia; Yin, Rui; Zhang, Yong-Liang; Cui, Wei-Jia; He, Tao

2018-01-01

Multidrug resistance (MDR) severely limits the effectiveness of chemotherapy. Previous studies have identified Twist as a key factor of acquired MDR in breast, gastric and prostate cancer. However, the underlying mechanisms of action of Twist in MDR remain unclear. In the present study, the expression levels of MDR-associated proteins, including lung resistance-related protein (LRP), topoisomerase IIα (TOPO IIα), MDR-associated protein (MRP) and P-glycoprotein (P-gp), and the expression of Twist in cancerous tissues and pericancerous tissues of human breast cancer, were examined. In order to simulate Taxol ® resistance in cells, a Taxol ® -resistant human mammary adenocarcinoma cell subline (MCF-7/Taxol ® ) was established by repeatedly exposing MCF-7 cells to high concentrations of Taxol ® (up to 15 µg/ml). Twist was also overexpressed in 293 cells by transfecting this cell line with pcDNA5/FRT/TO vector containing full-length hTwist cDNA to explore the dynamic association between Twist and MDR gene-associated proteins. It was identified that the expression levels of Twist, TOPO IIα, MRP and P-gp were upregulated and LRP was downregulated in human breast cancer tissues, which was consistent with the expression of these proteins in the Taxol ® -resistant MCF-7 cell model. Notably, the overexpression of Twist in 293 cells increased the resistance to Taxol ® , Trichostatin A and 5-fluorouracil, and also upregulated the expression of MRP and P-gp. Taken together, these data demonstrated that Twist may promote drug resistance in cells and cancer tissues through regulating the expression of MDR gene-associated proteins, which may assist in understanding the mechanisms of action of Twist in drug resistance.

Cerclage handling for improved fracture treatment. A biomechanical study on the twisting procedure.

PubMed

Wähnert, D; Lenz, M; Schlegel, U; Perren, S; Windolf, M

2011-01-01

Twisting is clinically the most frequently applied method for tightening and maintaining cerclage fixation. The twisting procedure is controversially discussed. Several factors during twisting affect the mechanical behaviour of the cerclage. This in vitro study investigated the influence of different parameters of the twisting procedure on the fixation strength of the cerclage in an experimental setup with centripetal force application. Cortical half shells of the femoral shaft were mounted on a testing fixture. 1.0 mm, 1.25 mm and 1.5 mm stainless ste- el wire cerclages as well as a 1.0mm cable cerclage were applied to the bone. Pretension of the cerclage during the installation was measured during the locking procedure. Subsequently, cyclic testing was performed up to failure. Higher pretension could be achieved with increasing wire diameter. However, with larger wire diameter the drop of pre- tension due to the bending and cutting the twist also increased. The cable cerclage showed the highest pretension after locking. Cerclages twisted under traction revealed significantly higher initial cerclage tension. Plastically deformed twists offered higher cerclage pretension compared to twists which were deformed in the elastic region of the material. Cutting the wire within the twist caused the highest loss of cerclage tension (44% initial tension) whereas only 11 % was lost when cutting the wire ends separately. The bending direction of the twist significantly influenced the cerclage pretension. 45% pretension was lost in forward bending of the twist, 53% in perpendicular bending and 90% in backward bending. Several parameters affect the quality of a cerclage fixation. Adequate installation of cerclage wires could markedly improve the clinical outcome of cerclage.

Strategy for robot motion and path planning in robot taping

NASA Astrophysics Data System (ADS)

Yuan, Qilong; Chen, I.-Ming; Lembono, Teguh Santoso; Landén, Simon Nelson; Malmgren, Victor

2016-06-01

Covering objects with masking tapes is a common process for surface protection in processes like spray painting, plasma spraying, shot peening, etc. Manual taping is tedious and takes a lot of effort of the workers. The taping process is a special process which requires correct surface covering strategy and proper attachment of the masking tape for an efficient surface protection. We have introduced an automatic robot taping system consisting of a robot manipulator, a rotating platform, a 3D scanner and specially designed taping end-effectors. This paper mainly talks about the surface covering strategies for different classes of geometries. The methods and corresponding taping tools are introduced for taping of following classes of surfaces: Cylindrical/extended surfaces, freeform surfaces with no grooves, surfaces with grooves, and rotational symmetrical surfaces. A collision avoidance algorithm is introduced for the robot taping manipulation. With further improvements on segmenting surfaces of taping parts and tape cutting mechanisms, such taping solution with the taping tool and the taping methodology can be combined as a very useful and practical taping package to assist humans in this tedious and time costly work.

Conical twist fields and null polygonal Wilson loops

NASA Astrophysics Data System (ADS)

Castro-Alvaredo, Olalla A.; Doyon, Benjamin; Fioravanti, Davide

2018-06-01

Using an extension of the concept of twist field in QFT to space-time (external) symmetries, we study conical twist fields in two-dimensional integrable QFT. These create conical singularities of arbitrary excess angle. We show that, upon appropriate identification between the excess angle and the number of sheets, they have the same conformal dimension as branch-point twist fields commonly used to represent partition functions on Riemann surfaces, and that both fields have closely related form factors. However, we show that conical twist fields are truly different from branch-point twist fields. They generate different operator product expansions (short distance expansions) and form factor expansions (large distance expansions). In fact, we verify in free field theories, by re-summing form factors, that the conical twist fields operator product expansions are correctly reproduced. We propose that conical twist fields are the correct fields in order to understand null polygonal Wilson loops/gluon scattering amplitudes of planar maximally supersymmetric Yang-Mills theory.

The TWIST/Mi2/NuRD protein complex and its essential role in cancer metastasis.

PubMed

Fu, Junjiang; Qin, Li; He, Tao; Qin, Jun; Hong, Jun; Wong, Jiemin; Liao, Lan; Xu, Jianming

2011-02-01

The epithelial-mesenchymal transition (EMT) converts epithelial tumor cells into invasive and metastatic cancer cells, leading to mortality in cancer patients. Although TWIST is a master regulator of EMT and metastasis for breast and other cancers, the mechanisms responsible for TWIST-mediated gene transcription remain unknown. In this study, purification and characterization of the TWIST protein complex revealed that TWIST interacts with several components of the Mi2/nucleosome remodeling and deacetylase (Mi2/NuRD) complex, MTA2, RbAp46, Mi2 and HDAC2, and recruits them to the proximal regions of the E-cadherin promoter for transcriptional repression. Depletion of these TWIST complex components from cancer cell lines that depend on TWIST for metastasis efficiently suppresses cell migration and invasion in culture and lung metastasis in mice. These findings not only provide novel mechanistic and functional links between TWIST and the Mi2/NuRD complex but also establish new essential roles for the components of Mi2/NuRD complex in cancer metastasis.

In Silico Measurements of Twist and Bend Moduli for β-Solenoid Protein Self-Assembly Units.

PubMed

Heinz, Leonard P; Ravikumar, Krishnakumar M; Cox, Daniel L

2015-05-13

We compute potentials of mean force for bend and twist deformations via force pulling and umbrella sampling experiments for four β-solenoid proteins (BSPs) that show promise in nanotechnology applications. In all cases, we find quasi-Hooke's law behavior until the point of rupture. Bending moduli show modest anisotropy for two-sided and three-sided BSPs, and little anisotropy for a four-sided BSP. There is a slight clockwise/counterclockwise asymmetry in the twist potential of mean force, showing greater stiffness when the applied twist follows the intrinsic twist. When we extrapolate to beam theory appropriate for amyloid fibrils of the BSPs, we find bend/twist moduli which are somewhat smaller than those in the literature for other amyloid fibrils. Twist persistence lengths are on the order of a micron, and bend persistence lengths are several microns. Provided the intrinsic twist can be reversed, these results support the usage of BSPs in biomaterials applications.

Systematic Review of the Effect of Taping Techniques on Patellofemoral Pain Syndrome.

PubMed

Logan, Catherine A; Bhashyam, Abhiram R; Tisosky, Ashley J; Haber, Daniel B; Jorgensen, Anna; Roy, Adam; Provencher, Matthew T

Taping is commonly used in the management of several musculoskeletal conditions, including patellofemoral pain syndrome (PFPS). Specific guidelines for taping are unknown. To investigate the efficacy of knee taping in the management of PFPS. Our hypothesis was that tension taping and exercise would be superior to placebo taping and exercise as well as to exercise or taping alone. The PubMed/MEDLINE, Cochrane, Rehabilitation and Sports Medicine Source, and CINAHL databases were reviewed for English-language randomized controlled trials (RCTs) evaluating the efficacy of various taping techniques that were published between 1995 and April 2015. Keywords utilized included taping, McConnell, kinesio-taping, kinesiotaping, patellofemoral pain, and knee. Studies included consisted of RCTs (level 1 or 2) with participants of all ages who had anterior knee or patellofemoral pain symptoms and had received nonsurgical management using any taping technique. Systematic review. Level 2. A checklist method was used to determine selection, performance, detection, and attrition bias for each article. A quality of evidence grading was then referenced using the validated PEDro database for RCTs. Three difference comparison groups were compared: tension taping and exercise versus placebo taping and exercise (group 1), placebo taping and exercise versus exercise alone (group 2), and tension taping and exercise versus taping alone (group 3). Five RCTs with 235 total patients with multiple intervention arms were included. Taping strategies included McConnell and Kinesiotaping. Visual analog scale (VAS) scores indicated improvement in all 3 comparison groups (group 1: 91 patients, 39% of total, mean VAS improvement 44.9 [tension taping + exercise] vs 66 [placebo taping + exercise]; group 2: 56 patients, 24% of total, mean VAS improvement 66 [placebo taping + exercise] vs 47.6 [exercise alone]; and group 3: 112 patients, 48% of total, mean VAS improvement 44.9 [tension taping + exercise] vs 14.1 [taping alone]). This systematic review supports knee taping only as an adjunct to traditional exercise therapy for PFPS; however, it does not support taping in isolation.

Analysis of lead twist in modern high-performance grinding methods

NASA Astrophysics Data System (ADS)

Kundrák, J.; Gyáni, K.; Felhő, C.; Markopoulos, AP; Deszpoth, I.

2016-11-01

According to quality requirements of road vehicles shafts, which bear dynamic seals, twisted-pattern micro-geometrical topography is not allowed. It is a question whether newer modern grinding methods - such as quick-point grinding and peel grinding - could provide twist- free topography. According to industrial experience, twist-free surfaces can be made, however with certain settings, same twist occurs. In this paper it is proved by detailed chip-geometrical analysis that the topography generated by the new procedures is theoretically twist-patterned because of the feeding motion of the CBN tool. The presented investigation was carried out by a single-grain wheel model and computer simulation.

Highly sensitive torsion sensor based on long period fiber grating fabricated by femtosecond laser pulses

NASA Astrophysics Data System (ADS)

Dong, Xinran; Xie, Zheng; Song, Yuxin; Yin, Kai; Luo, Zhi; Duan, Ji'an; Wang, Cong

2017-12-01

A highly sensitive torsion sensor based on long period fiber grating (LPFG) fabricated by 800 nm femtosecond laser pulses is proposed and demonstrated. LPFG with an attenuation depth of ∼14 dB is achieved within the wavelength range of 1425-1575 nm. The experiment results show that the LP02 and LP03 resonant wavelengths experience red-shift when the twist direction is clockwise while they occur blue-shift in the twist counterclockwise direction as the twist rate increases. However, the LP04 resonant wavelength is always shifted toward shorter wavelength independently of the twist directions and higher twist sensitivity is observed. In addition, the loss peak amplitude of LPFG shows a tendency to decrease with the twist rate increases whether the LPFG is twisted clockwise or counterclockwise. Meanwhile, the resonant wavelength occurs splitting phenomenon in the case of higher twist rate as well as the high order resonant wavelength performs more significantly. Additionally, the sensor shows a twist sensitivity as high as 118.7 pm/(rad/m) in the range of -105 to -52.5 rad/m and that of 181.7 pm/(rad/m) in the range of 52.5-105 rad/m.

Electronic and Optical Properties of Twisted Bilayer Graphene

NASA Astrophysics Data System (ADS)

Huang, Shengqiang

The ability to isolate single atomic layers of van der Waals materials has led to renewed interest in the electronic and optical properties of these materials as they can be fundamentally different at the monolayer limit. Moreover, these 2D crystals can be assembled together layer by layer, with controllable sequence and orientation, to form artificial materials that exhibit new features that are not found in monolayers nor bulk. Twisted bilayer graphene is one such prototype system formed by two monolayer graphene layers placed on top of each other with a twist angle between their lattices, whose electronic band structure depends on the twist angle. This thesis presents the efforts to explore the electronic and optical properties of twisted bilayer graphene by Raman spectroscopy and scanning tunneling microscopy measurements. We first synthesize twisted bilayer graphene with various twist angles via chemical vapor deposition. Using a combination of scanning tunneling microscopy and Raman spectroscopy, the twist angles are determined. The strength of the Raman G peak is sensitive to the electronic band structure of twisted bilayer graphene and therefore we use this peak to monitor changes upon doping. Our results demonstrate the ability to modify the electronic and optical properties of twisted bilayer graphene with doping. We also fabricate twisted bilayer graphene by controllable stacking of two graphene monolayers with a dry transfer technique. For twist angles smaller than one degree, many body interactions play an important role. It requires eight electrons per moire unit cell to fill up each band instead of four electrons in the case of a larger twist angle. For twist angles smaller than 0.4 degree, a network of domain walls separating AB and BA stacking regions forms, which are predicted to host topologically protected helical states. Using scanning tunneling microscopy and spectroscopy, these states are confirmed to appear on the domain walls when inversion symmetry is broken with an external electric field. We observe a double-line profile of these states on the domain walls, only occurring when the AB and BA regions are gaped. These states give rise to channels that could transport charge in a dissipationless manner making twisted bilayer graphene a promising platform to realize controllable topological networks for future applications.

Automated Tape Laying Machine for Composite Structures.

DTIC Science & Technology

The invention comprises an automated tape laying machine, for laying tape on a composite structure. The tape laying machine has a tape laying head...neatly cut. The automated tape laying device utilizes narrow width tape to increase machine flexibility and reduce wastage.

41 CFR 101-26.508 - Electronic data processing (EDP) tape and instrumentation tape (wide and intermediate band).

Code of Federal Regulations, 2013 CFR

2013-07-01

... processing (EDP) tape and instrumentation tape (wide and intermediate band). 101-26.508 Section 101-26.508... Programs § 101-26.508 Electronic data processing (EDP) tape and instrumentation tape (wide and intermediate band). Procurement by Federal agencies of EDP tape and instrumentation tape (wide and intermediate band...

41 CFR 101-26.508 - Electronic data processing (EDP) tape and instrumentation tape (wide and intermediate band).

Code of Federal Regulations, 2014 CFR

2014-07-01

... processing (EDP) tape and instrumentation tape (wide and intermediate band). 101-26.508 Section 101-26.508... Programs § 101-26.508 Electronic data processing (EDP) tape and instrumentation tape (wide and intermediate band). Procurement by Federal agencies of EDP tape and instrumentation tape (wide and intermediate band...

41 CFR 101-26.508 - Electronic data processing (EDP) tape and instrumentation tape (wide and intermediate band).

Code of Federal Regulations, 2010 CFR

2010-07-01

... processing (EDP) tape and instrumentation tape (wide and intermediate band). 101-26.508 Section 101-26.508... Programs § 101-26.508 Electronic data processing (EDP) tape and instrumentation tape (wide and intermediate band). Procurement by Federal agencies of EDP tape and instrumentation tape (wide and intermediate band...

41 CFR 101-26.508 - Electronic data processing (EDP) tape and instrumentation tape (wide and intermediate band).

Code of Federal Regulations, 2012 CFR

2012-07-01

... processing (EDP) tape and instrumentation tape (wide and intermediate band). 101-26.508 Section 101-26.508... Programs § 101-26.508 Electronic data processing (EDP) tape and instrumentation tape (wide and intermediate band). Procurement by Federal agencies of EDP tape and instrumentation tape (wide and intermediate band...

41 CFR 101-26.508 - Electronic data processing (EDP) tape and instrumentation tape (wide and intermediate band).

Code of Federal Regulations, 2011 CFR

2011-07-01

... processing (EDP) tape and instrumentation tape (wide and intermediate band). 101-26.508 Section 101-26.508... Programs § 101-26.508 Electronic data processing (EDP) tape and instrumentation tape (wide and intermediate band). Procurement by Federal agencies of EDP tape and instrumentation tape (wide and intermediate band...

Loss of Twist1 in the Mesenchymal Compartment Promotes Increased Fibrosis in Experimental Lung Injury by Enhanced Expression of CXCL12

PubMed Central

Tan, Jiangning; Tedrow, John R.; Nouraie, Mehdi; Dutta, Justin A.; Miller, David T.; Li, Xiaoyun; Yu, Shibing; Chu, Yanxia; Juan-Guardela, Brenda; Kaminski, Naftali; Ramani, Kritika; Biswas, Partha S.; Zhang, Yingze

2017-01-01

Idiopathic pulmonary fibrosis (IPF) is a disease characterized by the accumulation of apoptosis-resistant fibroblasts in the lung. We have previously shown that high expression of the transcription factor Twist1 may explain this prosurvival phenotype in vitro. However, this observation has never been tested in vivo. We found that loss of Twist1 in COL1A2+ cells led to increased fibrosis characterized by very significant accumulation of T cells and bone marrow–derived matrix-producing cells. We found that Twist1-null cells expressed high levels of the T cell chemoattractant CXCL12. In vitro, we found that the loss of Twist1 in IPF lung fibroblasts increased expression of CXCL12 downstream of increased expression of the noncanonical NF-κB transcription factor RelB. Finally, blockade of CXCL12 with AMD3100 attenuated the exaggerated fibrosis observed in Twist1-null mice. Transcriptomic analysis of 134 IPF patients revealed that low expression of Twist1 was characterized by enrichment of T cell pathways. In conclusion, loss of Twist1 in collagen-producing cells led to increased bleomycin-induced pulmonary fibrosis, which is mediated by increased expression of CXCL12. Twist1 expression is associated with dysregulation of T cells in IPF patients. Twist1 may shape the IPF phenotype and regulate inflammation in fibrotic lung injury. PMID:28179498

Tight Placement of Erich Arch Bar While Avoiding Wire Fatigue Failure.

PubMed

Kirk, Daniel; Whitney, Joseph; Shafer, David; Song, Liansheng

2016-03-01

To determine the number of wire twists needed to acquire ideal Erich arch bar tightness before wire fatigue failure (fracture) in relation to different distances and angles at which different gauge wires are grasped to provide information to improve the efficiency of arch bar application. This study mimicked surgical placement of arch bars with 24- and 26-gauge wires. The number of twists to tightness and failure was evaluated when the wire distance between the arch bar and wire holder tip changed (5 vs 10 mm) and when the degree at which the wire was held relative to the tooth axis was changed (45° vs 90°). A wire shearing test also was used to investigate the fatigability of wires tightened under these same conditions. Wires twisted to tightness, past tightness, and after shearing test movements were visualized with electron microscopy. For 24-gauge wire held at 5 mm, 2.6 to 2.8 twists were needed for wire tightness, with failure after 1.7 to 1.9 twists past tightness; for 24-gauge wire held at 10 mm, 4.4 to 4.9 twists produced tightness, with failure after 2.3 to 2.9 twists past tightness. For 26-gauge wire held at 5 mm, 3.3 to 3.5 twists provided tightness, with 1.6 to 1.8 twists past tightness causing failure; for 26-gauge wire held at 10 mm, 5.1 to 5.5 twists produced tightness, with 3.1 to 3.7 twists past tightness causing failure. At a 45° angle, the wire tightened with fewer twists and showed more resistance to failure with twists past tightness compared with 90° using 24- and 26-gauge wires. In contrast, 24-gauge wire held at a 5-mm distance showed the opposite result, with decreased resistance to failure at the 45° angle. However, the differences were not statistically meaningful. Scanning election microscopy showed no wire fatigue for either angle for 26-gauge wire held at a 5-mm distance and twisted to tightness. After overtightening and oscillation, the 90° angle trials showed fatigue, whereas the 45° angle trials did not. Holding a 24-gauge wire at 45° to the tooth axis is recommended owing to fewer twists to tightness and more resistance to failure. A 5-mm grasping distance is recommended for experienced surgeons owing to fewer twists to tightness, whereas a 10-mm grasping distance is recommended for novice surgeons owing to a greater tolerance for over-twisting before failure. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

TWIST1-WDR5-Hottip Regulates Hoxa9 Chromatin to Facilitate Prostate Cancer Metastasis.

PubMed

Malek, Reem; Gajula, Rajendra P; Williams, Russell D; Nghiem, Belinda; Simons, Brian W; Nugent, Katriana; Wang, Hailun; Taparra, Kekoa; Lemtiri-Chlieh, Ghali; Yoon, Arum R; True, Lawrence; An, Steven S; DeWeese, Theodore L; Ross, Ashley E; Schaeffer, Edward M; Pienta, Kenneth J; Hurley, Paula J; Morrissey, Colm; Tran, Phuoc T

2017-06-15

TWIST1 is a transcription factor critical for development that can promote prostate cancer metastasis. During embryonic development, TWIST1 and HOXA9 are coexpressed in mouse prostate and then silenced postnatally. Here we report that TWIST1 and HOXA9 coexpression are reactivated in mouse and human primary prostate tumors and are further enriched in human metastases, correlating with survival. TWIST1 formed a complex with WDR5 and the lncRNA Hottip/HOTTIP, members of the MLL/COMPASS-like H3K4 methylases, which regulate chromatin in the Hox/HOX cluster during development. TWIST1 overexpression led to coenrichment of TWIST1 and WDR5 as well as increased H3K4me3 chromatin at the Hoxa9/HOXA9 promoter, which was dependent on WDR5. Expression of WDR5 and Hottip/HOTTIP was also required for TWIST1-induced upregulation of HOXA9 and aggressive cellular phenotypes such as invasion and migration. Pharmacologic inhibition of HOXA9 prevented TWIST1-induced aggressive prostate cancer cellular phenotypes in vitro and metastasis in vivo This study demonstrates a novel mechanism by which TWIST1 regulates chromatin and gene expression by cooperating with the COMPASS-like complex to increase H3K4 trimethylation at target gene promoters. Our findings highlight a TWIST1-HOXA9 embryonic prostate developmental program that is reactivated during prostate cancer metastasis and is therapeutically targetable. Cancer Res; 77(12); 3181-93. ©2017 AACR . ©2017 American Association for Cancer Research.

Performance improvement in a tubular heat exchanger by punched delta-winglet vortex generators

NASA Astrophysics Data System (ADS)

Khanoknaiyakarn, C.; Promvonge, P.; Thianpong, C.; Skullong, S.

2018-01-01

A novel tubular heat exchanger incorporated with punched delta-winglet vortex generators (called perforated delta-winglet vortex generator, P-DWVG) is proposed for improving its thermal performance and energy saving. The P-DWVG elements are punched out from a straight tape having its width nearly equal to the tube diameter before insertion. The main aim at employing the P-DWVG insert is to produce counter-rotating vortices along the tube to promote turbulence intensity inside as well as to transport the cold fluid at the central core to the near-wall regions. The experiment was performed to study thermal behaviors in a uniform heat-fluxed tube inserted with P-DWVGs. The P-DWVGs with the attack angle of 45° were mounted periodically with three different blockage ratios (BR = 0.1, 0.2 and 0.3) and two pitch ratios (PR = 2 and 3). Air as the test fluid was varied to obtain turbulent airflow for Reynolds number (Re) in a range of 4,150-25,500. The experimental results show that the P-DWVG provides a considerable increase in the rate of heat transfer around 3.1-4.01 times whereas friction factor increases around 11.44- 34.23 times higher than the plain tube. To assess the real benefits of P-DWVGs, thermal performance factor (TEF) is examined and in the range of 1.39-1.48 where its maximum is at BR = 0.1 and PR = 2.

Improving the Spacelab mass memory unit tape layout with a simulation model

NASA Technical Reports Server (NTRS)

Noneman, S. R.

1984-01-01

A tape drive called the Mass Memory Unit (MMU) stores software used by Spacelab computers. MMU tape motion must be minimized during typical flight operations to avoid a loss of scientific data. A projection of the tape motion is needed for evaluation of candidate tape layouts. A computer simulation of the scheduled and unscheduled MMU tape accesses is developed for this purpose. This simulation permits evaluations of candidate tape layouts by tracking and summarizing tape movements. The factors that affect tape travel are investigated and a heuristic is developed to find a good tape layout. An improved tape layout for Spacelab I is selected after the evaluation of fourteen candidates. The simulation model will provide the ability to determine MMU layouts that substantially decrease the tape travel on future Spacelab flights.

EFFECT OF ATHLETIC TAPING AND KINESIOTAPING® ON MEASUREMENTS OF FUNCTIONAL PERFORMANCE IN BASKETBALL PLAYERS WITH CHRONIC INVERSION ANKLE SPRAINS

PubMed Central

Karatas, Nihan; Baltaci, Gul

2012-01-01

Background: Chronic inversion ankle sprains are common in basketball players. The effect of taping on functional performance is disputed in the literature. Kinesiotaping® (KT®) is a new method that is being used as both a therapeutic and performance enhancement tool. To date, it appears that no study has investigated the effect of ankle KT® on functional performance. Purpose: To investigate the effects of different types of taping (KT® using Kinesio Tex®, athletic taping) on functional performance in athletes with chronic inversion sprains of the ankle. Study Design: Crossover Study Design Methods: Fifteen male basketball players with chronic inversion ankle sprains between the ages of 18 and 22 participated in this study. Functional performance tests (Hopping test by Amanda et al, Single Limb Hurdle Test, Standing Heel Rise test, Vertical Jump Test, The Star Excursion Balance Test [SEBT] and Kinesthetic Ability Trainer [KAT] Test) were used to quantify agility, endurance, balance, and coordination. These tests were conducted four times at one week intervals using varied conditions: placebo tape, without tape, standard athletic tape, and KT®. One-way ANOVA tests were used to examine difference in measurements between conditions. Bonferroni correction was applied to correct for repeated testing. Results: There were no significant differences among the results obtained using the four conditions for SEBT (anterior p=0.0699; anteromedial p=0.126; medial p=0.550; posteromedial p=0.587; posterior p=0.754; posterolateral p=0.907; lateral p=0.124; anterolateral p=0.963) and the KAT dynamic measurement (p=0.388). Faster performance times were measured with KT® and athletic tape in single limb hurdle test when compared to placebo and non-taped conditions (Athletic taping- placebo taping: p=0.03; athletic taping- non tape p=0.016;KT®- Placebo taping p=0.042; KT®-Non tape p=0.016). In standing heel rise test and vertical jump test, athletic taping led to decreased performance. (Standing heel rise test: Athletic taping- placebo taping p=0.035; athletic taping- non tape p=0.043; athletic tape- KT® p<0.001) (Vertical jump test: Athletic taping- placebo taping p=0.002: athletic taping- non tape p=0.002; KT®- athletic tape p<0.001) Conclusion: Kinesiotaping® had no negative effects on a battery of functional performance tests and improvements were seen in some functional performance tests. Clinical Relevance: Ankle taping using Kinesio Tex® Tape did not inhibit functional performance. PMID:22530190

Effect of athletic taping and kinesiotaping® on measurements of functional performance in basketball players with chronic inversion ankle sprains.

PubMed

Bicici, Seda; Karatas, Nihan; Baltaci, Gul

2012-04-01

Chronic inversion ankle sprains are common in basketball players. The effect of taping on functional performance is disputed in the literature. Kinesiotaping® (KT®) is a new method that is being used as both a therapeutic and performance enhancement tool. To date, it appears that no study has investigated the effect of ankle KT® on functional performance. To investigate the effects of different types of taping (KT® using Kinesio Tex®, athletic taping) on functional performance in athletes with chronic inversion sprains of the ankle. Crossover Study Design Fifteen male basketball players with chronic inversion ankle sprains between the ages of 18 and 22 participated in this study. Functional performance tests (Hopping test by Amanda et al, Single Limb Hurdle Test, Standing Heel Rise test, Vertical Jump Test, The Star Excursion Balance Test [SEBT] and Kinesthetic Ability Trainer [KAT] Test) were used to quantify agility, endurance, balance, and coordination. These tests were conducted four times at one week intervals using varied conditions: placebo tape, without tape, standard athletic tape, and KT®. One-way ANOVA tests were used to examine difference in measurements between conditions. Bonferroni correction was applied to correct for repeated testing. There were no significant differences among the results obtained using the four conditions for SEBT (anterior p=0.0699; anteromedial p=0.126; medial p=0.550; posteromedial p=0.587; posterior p=0.754; posterolateral p=0.907; lateral p=0.124; anterolateral p=0.963) and the KAT dynamic measurement (p=0.388). Faster performance times were measured with KT® and athletic tape in single limb hurdle test when compared to placebo and non-taped conditions (Athletic taping- placebo taping: p=0.03; athletic taping- non tape p=0.016;KT®- Placebo taping p=0.042; KT®-Non tape p=0.016). In standing heel rise test and vertical jump test, athletic taping led to decreased performance. (Standing heel rise test: Athletic taping- placebo taping p=0.035; athletic taping- non tape p=0.043; athletic tape- KT® p<0.001) (Vertical jump test: Athletic taping- placebo taping p=0.002: athletic taping- non tape p=0.002; KT®- athletic tape p<0.001) Kinesiotaping® had no negative effects on a battery of functional performance tests and improvements were seen in some functional performance tests. Ankle taping using Kinesio Tex® Tape did not inhibit functional performance.

Chronic Pain Syndrome Caused by a Bird's Nest Filter: First Case Report

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

Al-Basheer, Mamoun Ahmad, E-mail: drbasheer30@yahoo.co; Hamilton, Mark; Holdaway, Chris

2008-07-15

AimTo report the first case of a Bird's Nest IVC filter causing a chronic pain syndrome lasting 13 years through IVC wall penetration and subsequent break off of one of the filter struts.Materials and ResultsA 43-year-old female presented with a 13-year history of abdominal pain following uneventful insertion of a Bird's Nest vena cava filter through a right internal jugular percutanous approach. A year following the procedure, CT scan revealed one arm of the filter to be outside IVC borders. Nine years from the date of insertion the nature of the pain changed acutely following a five feet jump tomore » more localized RUQ pain worse with twisting movements. A CT scan showed the strut to have pierced the IVC wall and penetrated the Unicate process of pancreas. Plain x-rays taken at different times in February 2006 showed one of the struts to be free floating in the peritoneal cavity. The floating strut was removed surgically from the wall of the Ileum. Postoperative recovery was uneventful and the patient was discharged pain free three days later.ConclusionChronic pain is an added complication of BNF devices. Although rare, it further emphasizes the need for long-term follow up of patients with IVC filters.« less

Isolation, characterization, and complementation of a motility mutant of Spiroplasma citri.

PubMed Central

Jacob, C; Nouzières, F; Duret, S; Bové, J M; Renaudin, J

1997-01-01

The helical mollicute Spiroplasma citri, when growing on low-agar medium, forms fuzzy colonies with occasional surrounding satellite colonies due to the ability of the spiroplasmal cells to move through the agar matrix. In liquid medium, these helical organisms flex, twist, and rotate rapidly. By using Tn4001 insertion mutagenesis, a motility mutant was isolated on the basis of its nondiffuse, sharp-edged colonies. Dark-field microscopy observations revealed that the organism flexed at a low frequency and had lost the ability to rotate about the helix axis. In this mutant, the transposon was shown to be inserted into an open reading frame encoding a putative polypeptide of 409 amino acids for which no significant homology with known proteins was found. The corresponding gene, named scm1, was recovered from the wild-type strain and introduced into the motility mutant by using the S. citri oriC plasmid pBOT1 as the vector. The appearance of fuzzy colonies and the observation that spiroplasma cells displayed rotatory and flexional movements showed the motile phenotype to be restored in the spiroplasmal transformants. The functional complementation of the motility mutant proves the scm1 gene product to be involved in the motility mechanism of S. citri. PMID:9244268

Define the Twist ATX LPAR1 Signaling Axis in Promoting Obesity Associated Triple Negative Breast Cancer

DTIC Science & Technology

2017-05-01

developed CRISPR technology to examine if Twist enhances ATX and LPAR1 expression. Specifically, we performed lentiviral transduction of Twist...targeting gRNA into breast cancer cells MDA-MB-578 and SUM-1315, and selected single cell colony with Twist knockout. We chose CRISPR -gRNA over the...shRNA system which was originally proposed, as CRISPR provides higher specificity and fewer off-target effects. To verify knockout of Twist, we first

Evaluation of a new silicone adhesive tape among clinicians caring for patients with fragile or at-risk skin.

PubMed

Manriquez, Sonia; Loperfido, Bonnie; Smith, Graham

2014-04-01

To evaluate performance of a new silicone tape among clinicians caring for patients with fragile skin. An international, multisite, 2-week-use evaluation. Caregivers (n = 217) from acute care hospitals in the United States, United Kingdom, and France who regularly use tapes on patients with fragile skin. The silicone tape was substituted for current-use gentle tapes for a 2-week trial period. Preuse and postuse questionnaires were collected. The main outcome measure was tape preference. Secondary outcomes included (1) satisfaction with current-use tapes, (2) willingness to replace current-use tapes with silicone tape, (3) performance comparisons between tapes, (4) clinician-reported problems with the silicone tape, and (5) case study information. The sample group consisted of nurses (98.1%), assistants (1.4%), and physicians (0.5%). Hospital units (n = 100) included oncology (31%), medical-surgical (14%), dialysis (12%), infusion/intravenous therapy (16%), critical care (10%), wound care (10%), and other units (7%). Overall preference was 92.0% for the silicone tape, 7.5% for current-use tapes, and 0.5% no preference. Dissatisfaction was 61.2% for current-use tapes, and most clinicians (90.2%) would change to the silicone tape. Evaluators favored (≥71.5%) the silicone tape on 10 performance attributes and on overall performance (91.6%). Most evaluators (75.1%) did not experience problems with the silicone tape, and those who did found problems related to adhesion (77.8%), gentleness (16.0%), and residue (6.2%). These results indicate that the silicone tape fills a performance-expectation gap of current acrylic tapes among users of tapes on patients with fragile or at-risk skin.

Highly sensitive twist sensor based on tilted fiber Bragg grating of polarization-dependent properties

NASA Astrophysics Data System (ADS)

Lu, Yanfang; Shen, Changyu; Chen, Debao; Chu, Jinlei; Wang, Qiang; Dong, Xinyong

2014-10-01

The transmission intensity of the tilted fiber Bragg grating (TFBG) is strongly dependent on the polarization properties of the TFBG. The polarization characteristic of the cladding modes can be used for twist measuring. In this paper, a highly sensitive fiber twist sensor is proposed. The transmission intensity on the strong loss wavelength showed a quasi-sin θ changing with the twist angle ranging from 0° to 180° for S- or P-polarized input. A high sensitivity of 0.299 dB/° is achieved, which is almost 17.9 times higher than that of the current similar existing twist sensor. The twist angle can be measured precisely with the matrix.

Au-coated tilted fiber Bragg grating twist sensor based on surface plasmon resonance

NASA Astrophysics Data System (ADS)

Shen, Changyu; Zhang, Yang; Zhou, Wenjun; Albert, Jacques

2014-02-01

A fiber twist sensor based on the surface plasmon resonance (SPR) effect of an Au-coated tilted fiber Bragg grating (TFBG) is proposed. The SPR response to the twist effect on an Au-coated TFBG (immersing in distilled water) is studied theoretically and experimentally. The results show that the transmission power around the wavelength of SPR changes with the twist angle. For the twist ranging from 0° to 180° in clockwise or anti-clockwise directions, the proposed sensor shows sensitivities of 0.037 dBm/° (S-polarized) and 0.039 dBm/° (P-polarized), which are almost 7.5 times higher than that of the current similar existing twist sensor.

Twisted complex superfluids in optical lattices

PubMed Central

Jürgensen, Ole; Sengstock, Klaus; Lühmann, Dirk-Sören

2015-01-01

We show that correlated pair tunneling drives a phase transition to a twisted superfluid with a complex order parameter. This unconventional superfluid phase spontaneously breaks the time-reversal symmetry and is characterized by a twisting of the complex phase angle between adjacent lattice sites. We discuss the entire phase diagram of the extended Bose—Hubbard model for a honeycomb optical lattice showing a multitude of quantum phases including twisted superfluids, pair superfluids, supersolids and twisted supersolids. Furthermore, we show that the nearest-neighbor interactions lead to a spontaneous breaking of the inversion symmetry of the lattice and give rise to dimerized density-wave insulators, where particles are delocalized on dimers. For two components, we find twisted superfluid phases with strong correlations between the species already for surprisingly small pair-tunneling amplitudes. Interestingly, this ground state shows an infinite degeneracy ranging continuously from a supersolid to a twisted superfluid. PMID:26345721

Accuracy testing of steel and electric groundwater-level measuring tapes: Test method and in-service tape accuracy

USGS Publications Warehouse

Fulford, Janice M.; Clayton, Christopher S.

2015-10-09

The calibration device and proposed method were used to calibrate a sample of in-service USGS steel and electric groundwater tapes. The sample of in-service groundwater steel tapes were in relatively good condition. All steel tapes, except one, were accurate to ±0.01 ft per 100 ft over their entire length. One steel tape, which had obvious damage in the first hundred feet, was marginally outside the accuracy of ±0.01 ft per 100 ft by 0.001 ft. The sample of in-service groundwater-level electric tapes were in a range of conditions—from like new, with cosmetic damage, to nonfunctional. The in-service electric tapes did not meet the USGS accuracy recommendation of ±0.01 ft. In-service electric tapes, except for the nonfunctional tape, were accurate to about ±0.03 ft per 100 ft. A comparison of new with in-service electric tapes found that steel-core electric tapes maintained their length and accuracy better than electric tapes without a steel core. The in-service steel tapes could be used as is and achieve USGS accuracy recommendations for groundwater-level measurements. The in-service electric tapes require tape corrections to achieve USGS accuracy recommendations for groundwater-level measurement.

The TWIST/Mi2/NuRD protein complex and its essential role in cancer metastasis

PubMed Central

Fu, Junjiang; Qin, Li; He, Tao; Qin, Jun; Hong, Jun; Wong, Jiemin; Liao, Lan; Xu, Jianming

2011-01-01

The epithelial-mesenchymal transition (EMT) converts epithelial tumor cells into invasive and metastatic cancer cells, leading to mortality in cancer patients. Although TWIST is a master regulator of EMT and metastasis for breast and other cancers, the mechanisms responsible for TWIST-mediated gene transcription remain unknown. In this study, purification and characterization of the TWIST protein complex revealed that TWIST interacts with several components of the Mi2/nucleosome remodeling and deacetylase (Mi2/NuRD) complex, MTA2, RbAp46, Mi2 and HDAC2, and recruits them to the proximal regions of the E-cadherin promoter for transcriptional repression. Depletion of these TWIST complex components from cancer cell lines that depend on TWIST for metastasis efficiently suppresses cell migration and invasion in culture and lung metastasis in mice. These findings not only provide novel mechanistic and functional links between TWIST and the Mi2/NuRD complex but also establish new essential roles for the components of Mi2/NuRD complex in cancer metastasis. PMID:20714342

The Effect of a Twisted Magnetic Field on the Phase Mixing of the Kink Magnetohydrodynamic Waves in Coronal Loops

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

Ebrahimi, Zanyar; Karami, Kayoomars; Soler, Roberto, E-mail: z.ebrahimi@uok.ac.ir

There is observational evidence for the existence of a twisted magnetic field in the solar corona. This inspires us to investigate the effect of a twisted magnetic field on the evolution of magnetohydrodynamic (MHD) kink waves in coronal loops. With this aim, we solve the incompressible linearized MHD equations in a magnetically twisted nonuniform coronal flux tube in the limit of long wavelengths. Our results show that a twisted magnetic field can enhance or diminish the rate of phase mixing of the Alfvén continuum modes and the decay rate of the global kink oscillation depending on the twist model andmore » the sign of the longitudinal ( k{sub z} ) and azimuthal ( m ) wavenumbers. Also, our results confirm that in the presence of a twisted magnetic field, when the sign of one of the two wavenumbers m and k {sub z} is changed, the symmetry with respect to the propagation direction is broken. Even a small amount of twist can have an important impact on the process of energy cascading to small scales.« less

Comparison of split double and triple twists in pair figure skating.

PubMed

King, Deborah L; Smith, Sarah L; Brown, Michele R; McCrory, Jean L; Munkasy, Barry A; Scheirman, Gary I

2008-05-01

In this study, we compared the kinematic variables of the split triple twist with those of the split double twist to help coaches and scientists understand these landmark pair skating skills. High-speed video was taken during the pair short and free programmes at the 2002 Salt Lake City Winter Olympics and the 2003 International Skating Union Grand Prix Finals. Three-dimensional analyses of 14 split double twists and 15 split triple twists from eleven pairs were completed. In spite of considerable variability in the performance variables among the pairs, the main difference between the split double twists and split triple twists was an increase in rotational rate. While eight of the eleven pairs relied primarily on an increased rotational rate to complete the split triple twist, three pairs employed a combined strategy of increased rotational rate and increased flight time due predominantly to delayed or lower catches. These results were similar to observations of jumps in singles skating for which the extra rotation is typically due to an increase in rotational velocity; increases in flight time come primarily from delayed landings as opposed to additional height during flight. Combining an increase in flight time and rotational rate may be a good strategy for completing the split triple twist in pair skating.

Insulin-like growth factor-I induces CLU expression through Twist1 to promote prostate cancer growth.

PubMed

Takeuchi, Ario; Shiota, Masaki; Beraldi, Eliana; Thaper, Daksh; Takahara, Kiyoshi; Ibuki, Naokazu; Pollak, Michael; Cox, Michael E; Naito, Seiji; Gleave, Martin E; Zoubeidi, Amina

2014-03-25

Clusterin (CLU) is cytoprotective molecular chaperone that is highly expressed in castrate-resistant prostate cancer (CRPC). CRPC is also characterized by increased insulin-like growth factor (IGF)-I responsiveness which induces prostate cancer survival and CLU expression. However, how IGF-I induces CLU expression and whether CLU is required for IGF-mediated growth signaling remain unknown. Here we show that IGF-I induced CLU via STAT3-Twist1 signaling pathway. In response to IGF-I, STAT3 was phosphorylated, translocated to the nucleus and bound to the Twist1 promoter to activate Twist1 transcription. In turn, Twist1 bound to E-boxes on the CLU promoter and activated CLU transcription. Inversely, we demonstrated that knocking down Twist1 abrogated IGF-I induced CLU expression, indicating that Twist1 mediated IGF-I-induced CLU expression. When PTEN knockout mice were crossed with lit/lit mice, the resultant IGF-I deficiency suppressed Twist1 as well as CLU gene expression in mouse prostate glands. Moreover, both Twist1 and CLU knockdown suppressed prostate cancer growth accelerated by IGF-I, suggesting the relevance of this signaling not only in an in vitro, but also in an in vivo. Collectively, this study indicates that IGF-I induces CLU expression through sequential activation of STAT3 and Twist1, and suggests that this signaling cascade plays a critical role in prostate cancer pathogenesis. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Twist number and order properties of periodic orbits

NASA Astrophysics Data System (ADS)

Petrisor, Emilia

2013-11-01

A less studied numerical characteristic of periodic orbits of area preserving twist maps of the annulus is the twist or torsion number, called initially the amount of rotation Mather (1984) [2]. It measures the average rotation of tangent vectors under the action of the derivative of the map along that orbit, and characterizes the degree of complexity of the dynamics. The aim of this paper is to give new insights into the definition and properties of the twist number and to relate its range to the order properties of periodic orbits. We derive an algorithm to deduce the exact value or a demi-unit interval containing the exact value of the twist number. We prove that at a period-doubling bifurcation threshold of a mini-maximizing periodic orbit, the new born doubly periodic orbit has the absolute twist number larger than the absolute twist of the original orbit after bifurcation. We give examples of periodic orbits having large absolute twist number, that are badly ordered, and illustrate how characterization of these orbits only by their residue can lead to incorrect results. In connection to the study of the twist number of periodic orbits of standard-like maps we introduce a new tool, called 1-cone function. We prove that the location of minima of this function with respect to the vertical symmetry lines of a standard-like map encodes a valuable information on the symmetric periodic orbits and their twist number.

How is the relationship between TWIST-1 and BCR-ABL1 gene expressions in chronic myeloid leukaemia patients?

PubMed

Heidari, Nazanin; Vosoughi, Tina; Mohammadi Asl, Javad; Saki Malehi, Amal; Saki, Najmaldin

2018-01-12

The activation and increased expression of BCR-ABL1 lead to malignant chronic myelogenous leukaemia (CML) cells, as well as the resistance to antitumour agents and apoptosis inducers. Moreover, TWIST-1 protein is a prognostic factor of leukemogenesis, and its level is raised in CML patients with cytogenetic resistance to imatinib. So, there is a likely relationship between BCR-ABL1 and TWIST-1 genes. The aim of the study was to assess the relationship between TWIST-1 and BCR-ABL1 expressions. Peripheral blood samples were obtained from 44 CML patients under treatment and also from ten healthy subjects as normal controls. The expression of TWIST-1 and BCR-ABL1 genes was measured using real-time PCR, and ABL1 was used as the reference gene. The gene expression was evaluated by REST software. The expression levels of TWIST-1 and BCR-ABL1 genes in CML patients was changed 40.23 ± 177.75-fold and 6 ± 18-fold, respectively. No significant relationship was observed between the expressions of TWIST-1 and BCR-ABL1 genes. All patients with TWIST-1 expression levels ≥100-fold had failure of response to treatment. The probability of the relationship between BCR-ABL1 and TWIST-1 is still debatable, and the average of TWIST-1 expression has been higher in patients without response to treatment. Definitive conclusion needs further investigations.

Optimal flapping wing for maximum vertical aerodynamic force in hover: twisted or flat?

PubMed

Phan, Hoang Vu; Truong, Quang Tri; Au, Thi Kim Loan; Park, Hoon Cheol

2016-07-08

This work presents a parametric study, using the unsteady blade element theory, to investigate the role of twist in a hovering flapping wing. For the investigation, a flapping-wing system was developed to create a wing motion of large flapping amplitude. Three-dimensional kinematics of a passively twisted wing, which is capable of creating a linearly variable geometric angle of attack (AoA) along the wingspan, was measured during the flapping motion and used for the analysis. Several negative twist or wash-out configurations with different values of twist angle, which is defined as the difference in the average geometric AoAs at the wing root and the wing tip, were obtained from the measured wing kinematics through linear interpolation and extrapolation. The aerodynamic force generation and aerodynamic power consumption of these twisted wings were obtained and compared with those of flat wings. For the same aerodynamic power consumption, the vertical aerodynamic forces produced by the negatively twisted wings are approximately 10%-20% less than those produced by the flat wings. However, these twisted wings require approximately 1%-6% more power than flat wings to produce the same vertical force. In addition, the maximum-force-producing twisted wing, which was found to be the positive twist or wash-in configuration, was used for comparison with the maximum-force-producing flat wing. The results revealed that the vertical aerodynamic force and aerodynamic power consumption of the two types of wings are almost identical for the hovering condition. The power loading of the positively twisted wing is only approximately 2% higher than that of the maximum-force-producing flat wing. Thus, the flat wing with proper wing kinematics (or wing rotation) can be regarded as a simple and efficient candidate for the development of hovering flapping-wing micro air vehicle.

Epigenetic inactivation of TWIST2 in acute lymphoblastic leukemia modulates proliferation, cell survival and chemosensitivity

PubMed Central

Thathia, Shabnam H.; Ferguson, Stuart; Gautrey, Hannah E.; van Otterdijk, Sanne D.; Hili, Michela; Rand, Vikki; Moorman, Anthony V.; Meyer, Stefan; Brown, Robert; Strathdee, Gordon

2012-01-01

Background Altered regulation of many transcription factors has been shown to be important in the development of leukemia. TWIST2 modulates the activity of a number of important transcription factors and is known to be a regulator of hematopoietic differentiation. Here, we investigated the significance of epigenetic regulation of TWIST2 in the control of cell growth and survival and in response to cytotoxic agents in acute lymphoblastic leukemia. Design and Methods TWIST2 promoter methylation status was assessed quantitatively, by combined bisulfite and restriction analysis (COBRA) and pyrosequencing assays, in multiple types of leukemia and TWIST2 expression was determined by quantitative reverse transcriptase polymerase chain reaction analysis. The functional role of TWIST2 in cell proliferation, survival and response to chemotherapy was assessed in transient and stable expression systems. Results We found that TWIST2 was inactivated in more than 50% of cases of childhood and adult acute lymphoblastic leukemia through promoter hypermethylation and that this epigenetic regulation was especially prevalent in RUNX1-ETV6-driven cases. Re-expression of TWIST2 in cell lines resulted in a dramatic reduction in cell growth and induction of apoptosis in the Reh cell line. Furthermore, re-expression of TWIST2 resulted in increased sensitivity to the chemotherapeutic agents etoposide, daunorubicin and dexamethasone and TWIST2 hypermethylation was almost invariably found in relapsed adult acute lymphoblastic leukemia (91% of samples hypermethylated). Conclusions This study suggests a dual role for epigenetic inactivation of TWIST2 in acute lymphoblastic leukemia, initially through altering cell growth and survival properties and subsequently by increasing resistance to chemotherapy. PMID:22058208

The Effects of Exercise Intensity vs. Metabolic State on the Variability and Magnitude of Left Ventricular Twist Mechanics during Exercise

PubMed Central

Armstrong, Craig; Samuel, Jake; Yarlett, Andrew; Cooper, Stephen-Mark; Stembridge, Mike; Stöhr, Eric J.

2016-01-01

Increased left ventricular (LV) twist and untwisting rate (LV twist mechanics) are essential responses of the heart to exercise. However, previously a large variability in LV twist mechanics during exercise has been observed, which complicates the interpretation of results. This study aimed to determine some of the physiological sources of variability in LV twist mechanics during exercise. Sixteen healthy males (age: 22 ± 4 years, V˙O2peak: 45.5 ± 6.9 ml∙kg-1∙min-1, range of individual anaerobic threshold (IAT): 32–69% of V˙O2peak) were assessed at rest and during exercise at: i) the same relative exercise intensity, 40%peak, ii) at 2% above IAT, and, iii) at 40%peak with hypoxia (40%peak+HYP). LV volumes were not significantly different between exercise conditions (P > 0.05). However, the mean margin of error of LV twist was significantly lower (F2,47 = 2.08, P < 0.05) during 40%peak compared with IAT (3.0 vs. 4.1 degrees). Despite the same workload and similar LV volumes, hypoxia increased LV twist and untwisting rate (P < 0.05), but the mean margin of error remained similar to that during 40%peak (3.2 degrees, P > 0.05). Overall, LV twist mechanics were linearly related to rate pressure product. During exercise, the intra-individual variability of LV twist mechanics is smaller at the same relative exercise intensity compared with IAT. However, the absolute magnitude (degrees) of LV twist mechanics appears to be associated with the prevailing rate pressure product. Exercise tests that evaluate LV twist mechanics should be standardised by relative exercise intensity and rate pressure product be taken into account when interpreting results. PMID:27100099

The Effects of Exercise Intensity vs. Metabolic State on the Variability and Magnitude of Left Ventricular Twist Mechanics during Exercise.

PubMed

Armstrong, Craig; Samuel, Jake; Yarlett, Andrew; Cooper, Stephen-Mark; Stembridge, Mike; Stöhr, Eric J

2016-01-01

Increased left ventricular (LV) twist and untwisting rate (LV twist mechanics) are essential responses of the heart to exercise. However, previously a large variability in LV twist mechanics during exercise has been observed, which complicates the interpretation of results. This study aimed to determine some of the physiological sources of variability in LV twist mechanics during exercise. Sixteen healthy males (age: 22 ± 4 years, [Formula: see text]O2peak: 45.5 ± 6.9 ml∙kg-1∙min-1, range of individual anaerobic threshold (IAT): 32-69% of [Formula: see text]O2peak) were assessed at rest and during exercise at: i) the same relative exercise intensity, 40%peak, ii) at 2% above IAT, and, iii) at 40%peak with hypoxia (40%peak+HYP). LV volumes were not significantly different between exercise conditions (P > 0.05). However, the mean margin of error of LV twist was significantly lower (F2,47 = 2.08, P < 0.05) during 40%peak compared with IAT (3.0 vs. 4.1 degrees). Despite the same workload and similar LV volumes, hypoxia increased LV twist and untwisting rate (P < 0.05), but the mean margin of error remained similar to that during 40%peak (3.2 degrees, P > 0.05). Overall, LV twist mechanics were linearly related to rate pressure product. During exercise, the intra-individual variability of LV twist mechanics is smaller at the same relative exercise intensity compared with IAT. However, the absolute magnitude (degrees) of LV twist mechanics appears to be associated with the prevailing rate pressure product. Exercise tests that evaluate LV twist mechanics should be standardised by relative exercise intensity and rate pressure product be taken into account when interpreting results.

Tyrosine kinase receptor c-ros-oncogene 1 inhibition alleviates aberrant bone formation of TWIST-1 haploinsufficient calvarial cells from Saethre-Chotzen syndrome patients.

PubMed

Camp, Esther; Anderson, Peter J; Zannettino, Andrew C W; Glackin, Carlotta A; Gronthos, Stan

2018-09-01

Saethre-Chotzen syndrome (SCS), associated with TWIST-1 mutations, is characterized by premature fusion of cranial sutures. TWIST-1 haploinsufficiency, leads to alterations in suture mesenchyme cellular gene expression patterns, resulting in aberrant osteogenesis and craniosynostosis. We analyzed the expression of the TWIST-1 target, Tyrosine kinase receptor c-ros-oncogene 1 (C-ROS-1) in TWIST-1 haploinsufficient calvarial cells derived from SCS patients and calvaria of Twist-1 del/+ mutant mice and found it to be highly expressed when compared to TWIST-1 wild-type controls. Knock-down of C-ROS-1 expression in TWIST-1 haploinsufficient calvarial cells derived from SCS patients was associated with decreased capacity for osteogenic differentiation in vitro. Furthermore, treatment of human SCS calvarial cells with the tyrosine kinase chemical inhibitor, Crizotinib, resulted in reduced C-ROS-1 activity and the osteogenic potential of human SCS calvarial cells with minor effects on cell viability or proliferation. Cultured human SCS calvarial cells treated with Crizotinib exhibited a dose-dependent decrease in alkaline phosphatase activity and mineral deposition, with an associated decrease in expression levels of Runt-related transcription factor 2 and OSTEOPONTIN, with reduced PI3K/Akt signalling in vitro. Furthermore, Crizotinib treatment resulted in reduced BMP-2 mediated bone formation potential of whole Twist-1 del/+ mutant mouse calvaria organotypic cultures. Collectively, these results suggest that C-ROS-1 promotes osteogenic differentiation of TWIST-1 haploinsufficient calvarial osteogenic progenitor cells. Furthermore, the aberrant osteogenic potential of these cells is inhibited by the reduction of C-ROS-1. Therefore, targeting C-ROS-1 with a pharmacological agent, such as Crizotinib, may serve as a novel therapeutic strategy to alleviate craniosynostosis associated with aberrant TWIST-1 function. © 2018 Wiley Periodicals, Inc.

Magnetic Tape Recording for the Eighties

NASA Technical Reports Server (NTRS)

Kalil, Ford (Editor)

1982-01-01

The practical and theoretical aspects of state-of-the-art magnetic tape recording technology are reviewed. Topics covered include the following: (1) analog and digital magnetic tape recording, (2) tape and head wear, (3) wear testing, (4) magnetic tape certification, (5) care, handling, and management of magnetic tape, (6) cleaning, packing, and winding of magnetic tape, (7) tape reels, bands, and packaging, (8) coding techniques for high-density digital recording, and (9) tradeoffs of coding techniques.

An Experimental Investigation of Damaged Arresting Gear Tapes for the Langley Aircraft Landing Dynamics Facility

NASA Technical Reports Server (NTRS)

Mason, Angela J.

1999-01-01

An experimental investigation was performed on damaged arresting gear tapes at the Langley Aircraft Landing Dynamics Facility. The arrestment system uses five pairs of tapes to bring the test carriage to a halt. The procedure used to determine when to replace the tapes consists of a close evaluation of each of the 10 tapes after each run. During this evaluation, each tape is examined thoroughly and any damage observed on the tape is recorded. If the damaged tape does not pass the inspection, the tape is replaced with a new one. For the past 13 years, the most commonly seen damage types are edge fray damage and transverse damage. Tests were conducted to determine the maximum tensile strength of a damaged arresting gear tape specimen. The data indicate that tapes exhibiting transverse damage can withstand higher loads than tapes with edge fray damage.

Biomechanical and histologic basis of osseodensification drilling for endosteal implant placement in low density bone. An experimental study in sheep.

PubMed

Lahens, Bradley; Neiva, Rodrigo; Tovar, Nick; Alifarag, Adham M; Jimbo, Ryo; Bonfante, Estevam A; Bowers, Michelle M; Cuppini, Marla; Freitas, Helora; Witek, Lukasz; Coelho, Paulo G

2016-10-01

A bone drilling concept, namely osseodensification, has been introduced for the placement of endosteal implants to increase primary stability through densification of the osteotomy walls. This study investigated the effect of osseodensification on the initial stability and early osseointegration of conical and parallel walled endosteal implants in low density bone. Five male sheep were used. Three implants were inserted in the ilium, bilaterally, totaling 30 implants (n=15 conical, and n=15 parallel). Each animal received 3 implants of each type, inserted into bone sites prepared as follows: (i) regular-drilling (R: 2mm pilot, 3.2mm, and 3.8mm twist drills), (ii) clockwise osseodensification (CW), and (iii) counterclockwise (CCW) osseodensification drilling with Densah Bur (Versah, Jackson, MI, USA): 2.0mm pilot, 2.8mm, and 3.8mm multi-fluted burs. Insertion torque as a function of implant type and drilling technique, revealed higher values for osseodensification relative to R-drilling, regardless of implant macrogeometry. A significantly higher bone-to-implant contact (BIC) for both osseodensification techniques (p<0.05) was observed compared to R-drilling. There was no statistical difference in BIC as a function of implant type (p=0.58), nor in bone-area-fraction occupancy (BAFO) as a function of drilling technique (p=0.22), but there were higher levels of BAFO for parallel than conic implants (p=0.001). Six weeks after surgery, new bone formation along with remodeling sites was observed for all groups. Bone chips in proximity with the implants were seldom observed in the R-drilling group, but commonly observed in the CW, and more frequently under the CCW osseodensification technique. In low-density bone, endosteal implants present higher insertion torque levels when placed in osseodensification drilling sites, with no osseointegration impairment compared to standard subtractive drilling methods. Copyright © 2016 Elsevier Ltd. All rights reserved.

Folding Properties of Cytosine Monophosphate Kinase from E. coli Indicate Stabilization through an Additional Insert in the NMP Binding Domain

PubMed Central

Beitlich, Thorsten; Lorenz, Thorsten; Reinstein, Jochen

2013-01-01

The globular 25 kDa protein cytosine monophosphate kinase (CMPK, EC ID: 2.7.4.14) from E. coli belongs to the family of nucleoside monophosphate (NMP) kinases (NMPK). Many proteins of this family share medium to high sequence and high structure similarity including the frequently found α/β topology. A unique feature of CMPK in the family of NMPKs is the positioning of a single cis-proline residue in the CORE-domain (cis-Pro124) in conjunction with a large insert in the NMP binding domain. This insert is not found in other well studied NMPKs such as AMPK or UMP/CMPK. We have analyzed the folding pathway of CMPK using time resolved tryptophan and FRET fluorescence as well as CD. Our results indicate that unfolding at high urea concentrations is governed by a single process, whereas refolding in low urea concentrations follows at least a three step process which we interpret as follows: Pro124 in the CORE-domain is in cis in the native state (Nc) and equilibrates with its trans-isomer in the unfolded state (Uc - Ut). Under refolding conditions, at least the Ut species and possibly also the Uc species undergo a fast initial collapse to form intermediates with significant amount of secondary structure, from which the trans-Pro124 fraction folds to the native state with a 100-fold lower rate constant than the cis-Pro124 species. CMPK thus differs from homologous NMP kinases like UMP/CMP kinase or AMP kinase, where folding intermediates show much lower content of secondary structure. Importantly also unfolding is up to 100-fold faster compared to CMPK. We therefore propose that the stabilizing effect of the long NMP-domain insert in conjunction with a subtle twist in the positioning of a single cis-Pro residue allows for substantial stabilization compared to other NMP kinases with α/β topology. PMID:24205218

Twist-induced tuning in tapered fiber couplers.

PubMed

Birks, T A

1989-10-01

The power-splitting ratio of fused tapered single-mode fiber couplers can be reversibly tuned by axial twisting without affecting loss. The twist-tuning behavior of a range of different tapered couplers is described. A simple expression for twist-tuning can be derived by representing the effects of twist by a change in the refractive index profile. Good agreement between this expression and experimental results is demonstrated. Repeated tuning over tens of thousands of cycles is found not to degrade coupler performance, and a number of practical applications, including a freely tunable tapered coupler, are described.

Twirling and Whirling: Viscous Dynamics of Rotating Elastica

NASA Astrophysics Data System (ADS)

Wolgemuth, Charles; Powers, Thomas; Goldstein, Raymond

1999-10-01

The stability of forced elastic filaments arise in several important biological settings involving bend and twist elasticity at low Reynolds number. Examples include DNA transcription and replication and bacterial flagellar motion. In order to elucidate fundamental processes common to these systems, we consider the model problem of a rotationally forced filament with twist and bend elasticity. Competition between twist injection, twist diffusion, and writhing instabilities is described by a novel pair of PDEs for twist and bend evolution. Analytical and numerical methods elucidate the twist/bend coupling and reveal two dynamical regimes seperated by a Hopf bifurcation: (i) diffusion-dominated axial rotation, or twirling, and (ii) steady-state crankshafting motion, or whirling. Experiments are proposed to examine these phenomena and the consequences for swimming investigated.

Analysis of cache for streaming tape drive

NASA Technical Reports Server (NTRS)

Chinnaswamy, V.

1993-01-01

A tape subsystem consists of a controller and a tape drive. Tapes are used for backup, data interchange, and software distribution. The backup operation is addressed. During a backup operation, data is read from disk, processed in CPU, and then sent to tape. The processing speeds of a disk subsystem, CPU, and a tape subsystem are likely to be different. A powerful CPU can read data from a fast disk, process it, and supply the data to the tape subsystem at a faster rate than the tape subsystem can handle. On the other hand, a slow disk drive and a slow CPU may not be able to supply data fast enough to keep a tape drive busy all the time. The backup process may supply data to tape drive in bursts. Each burst may be followed by an idle period. Depending on the nature of the file distribution in the disk, the input stream to the tape subsystem may vary significantly during backup. To compensate for these differences and optimize the utilization of a tape subsystem, a cache or buffer is introduced in the tape controller. Most of the tape drives today are streaming tape drives. A streaming tape drive goes into reposition when there is no data from the controller. Once the drive goes into reposition, the controller can receive data, but it cannot supply data to the tape drive until the drive completes its reposition. A controller can also receive data from the host and send data to the tape drive at the same time. The relationship of cache size, host transfer rate, drive transfer rate, reposition, and ramp up times for optimal performance of the tape subsystem are investigated. Formulas developed will also show the advantages of cache watermarks to increase the streaming time of the tape drive, maximum loss due to insufficient cache, tradeoffs between cache and reposition times and the effectiveness of cache on a streaming tape drive due to idle times or interruptions due in host transfers. Several mathematical formulas are developed to predict the performance of the tape drive. Some examples are given illustrating the usefulness of these formulas. Finally, a summary and some conclusions are provided.

Prototyping phase of the high heat flux scraper element of Wendelstein 7-X

DOE PAGES

Boscary, Jean; Greuner, Henri; Ehrke, G.; ...

2016-03-24

The water-cooled high heat flux scraper element aims to reduce excessive heat loads on the target element ends of the actively cooled divertor of Wendelstein 7-X. Its purpose is to intercept some of the plasma fluxes both upstream and downstream before they reach the divertor surface. The scraper element has 24 identical plasma facing components (PFCs) divided into 6 modules. One module has 4 PFCs hydraulically connected in series by 2 water boxes. A PFC, 247 mm long and 28 mm wide, has 13 monoblocks made of CFC NB31 bonded by hot isostatic pressing onto a CuCrZr cooling tube equippedmore » with a copper twisted tape. 4 full-scale prototypes of PFCs have been successfully tested in the GLADIS facility up to 20 MW/m 2. The difference observed between measured and calculated surface temperatures is probably due to the inhomogeneity of CFC properties. The design of the water box prototypes has been detailed to allow the junction between the cooling pipe of the PFCs and the water boxes by internal orbital welding. In conclusion, the prototypes are presently under fabrication.« less

Performance measurements and operational characteristics of the Storage Tek ACS 4400 tape library with the Cray Y-MP EL

NASA Technical Reports Server (NTRS)

Hull, Gary; Ranade, Sanjay

1993-01-01

With over 5000 units sold, the Storage Tek Automated Cartridge System (ACS) 4400 tape library is currently the most popular large automated tape library. Based on 3480/90 tape technology, the library is used as the migration device ('nearline' storage) in high-performance mass storage systems. In its maximum configuration, one ACS 4400 tape library houses sixteen 3480/3490 tape drives and is capable of holding approximately 6000 cartridge tapes. The maximum storage capacity of one library using 3480 tapes is 1.2 TB and the advertised aggregate I/O rate is about 24 MB/s. This paper reports on an extensive set of tests designed to accurately assess the performance capabilities and operational characteristics of one STK ACS 4400 tape library holding approximately 5200 cartridge tapes and configured with eight 3480 tape drives. A Cray Y-MP EL2-256 was configured as its host machine. More than 40,000 tape jobs were run in a variety of conditions to gather data in the areas of channel speed characteristics, robotics motion, time taped mounts, and timed tape reads and writes.

Playback Station #2 for Cal Net and 5-day-recorder tapes

USGS Publications Warehouse

Eaton, Jerry P.

1978-01-01

A second system (Playback Station #2) has been set up to play back Cal Net 1" tapes and 5-day-recorder 1/2" tapes. As with the first playback system (Playback Station #1) the tapes are played back on a Bell and Howell VR3700B tape deck and the records are written out on a 16-channel direct-writing Siemens "0scillomink." Separate reproduce heads, tape guides, and tape tension sensor rollers are required for playing back 111 tapes and 1/2" tapes, but changing these tape deck components is a simple task that requires only a few minutes. The discriminators, patch panels, selector switches, filters, time code translators, and signal conditioning circuits for the time code translators and for the tape-speed-compensation signal are all mounted in an equipment rack that stands beside the playback tape deck. Changing playback speeds (15/16 ips or 3 3/4 ips) or changing from Cal Net tapes to 5-day-recorder tapes requires only flipping a few switches and/or changing a few patch cables on the patch panel (in addition to changing the reproduce heads, etc., to change from 1" tape to 1/2" tape). For the Cal Net tapes, the system provides for playback of 9 data channels (680 Hz thru 3060 Hz plus 400 Hz) and 3 time signals (IRIG-E, IRIG-C, and WWVB) at both 15/16 ips (x1 speed) and 3 3/4 ips (x4 speed). Available modes of compensation (using either a 4688 Hz reference or a 3125 Hz reference) are subtractive, capstan, capstan plus subtractive, or no compensation.

Effect of Magnetic Twist on Nonlinear Transverse Kink Oscillations of Line-tied Magnetic Flux Tubes

NASA Astrophysics Data System (ADS)

Terradas, J.; Magyar, N.; Van Doorsselaere, T.

2018-01-01

Magnetic twist is thought to play an important role in many structures of the solar atmosphere. One of the effects of twist is to modify the properties of the eigenmodes of magnetic tubes. In the linear regime standing kink solutions are characterized by a change in polarization of the transverse displacement along the twisted tube. In the nonlinear regime, magnetic twist affects the development of shear instabilities that appear at the tube boundary when it is oscillating laterally. These Kelvin–Helmholtz instabilities (KHI) are produced either by the jump in the azimuthal component of the velocity at the edge of the sharp boundary between the internal and external part of the tube or by the continuous small length scales produced by phase mixing when there is a smooth inhomogeneous layer. In this work the effect of twist is consistently investigated by solving the time-dependent problem including the process of energy transfer to the inhomogeneous layer. It is found that twist always delays the appearance of the shear instability, but for tubes with thin inhomogeneous layers the effect is relatively small for moderate values of twist. On the contrary, for tubes with thick layers, the effect of twist is much stronger. This can have some important implications regarding observations of transverse kink modes and the KHI itself.

Sox5 induces epithelial to mesenchymal transition by transactivation of Twist1

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

Pei, Xin-Hong; Department of Pathology, The Basic Medical College of Zhengzhou University, Zhengzhou, Henan; Lv, Xin-Quan

2014-03-28

Highlights: • Depletion of Sox5 inhibits breast cancer proliferation, migration, and invasion. • Sox5 transactivates Twist1 expression. • Sox5 induces epithelial to mesenchymal transition through transactivation of Twist1 expression. - Abstract: The epithelial to mesenchymal transition (EMT), a highly conserved cellular program, plays an important role in normal embryogenesis and cancer metastasis. Twist1, a master regulator of embryonic morphogenesis, is overexpressed in breast cancer and contributes to metastasis by promoting EMT. In exploring the mechanism underlying the increased Twist1 in breast cancer cells, we found that the transcription factor SRY (sex-determining region Y)-box 5(Sox5) is up-regulation in breast cancer cellsmore » and depletion of Sox5 inhibits breast cancer cell proliferation, migration, and invasion. Furthermore, depletion of Sox5 in breast cancer cells caused a dramatic decrease in Twist1 and chromosome immunoprecipitation assay showed that Sox5 can bind directly to the Twist1 promoter, suggesting that Sox5 transactivates Twist1 expression. We further demonstrated that knockdown of Sox5 up-regulated epithelial phenotype cell biomarker (E-cadherin) and down-regulated mesenchymal phenotype cell biomarkers (N-cadherin, Vimentin, and Fibronectin 1), resulting in suppression of EMT. Our study suggests that Sox5 transactivates Twist1 expression and plays an important role in the regulation of breast cancer progression.« less

Self-contained instrument for measuring subterranean tunnel wall deflection

DOEpatents

Rasmussen, Donald Edgar; Hof, Jr., Peter John

1978-01-01

The deflection of a subterranean tunnel is measured with a rod-like, self-contained instrument that is adapted to be inserted into a radially extending bore of the tunnel adjacent an end of the tunnel where the tunnel is being dug. One end of the instrument is anchored at the end of the bore remote from the tunnel wall, while the other end of the intrument is anchored adjacent the end of the wall in proximity to the tunnel wall. The two ends of the instrument are linearly displaceable relative to each other; the displacement is measured by a transducer means mounted on the instrument. Included in the instrument is a data storage means including a paper tape recorder periodically responsive to a parallel binary signal indicative of the measured displacement.

Wire harness twisting aid

NASA Technical Reports Server (NTRS)

Casey, E. J.; Commadore, C. C.; Ingles, M. E.

1980-01-01

Long wire bundles twist into uniform spiral harnesses with help of simple apparatus. Wires pass through spacers and through hand-held tool with hole for each wire. Ends are attached to low speed bench motor. As motor turns, operator moves hand tool away forming smooth twists in wires between motor and tool. Technique produces harnesses that generate less radio-frequency interference than do irregularly twisted cables.

Twist Model Development and Results from the Active Aeroelastic Wing F/A-18 Aircraft

NASA Technical Reports Server (NTRS)

Lizotte, Andrew M.; Allen, Michael J.

2007-01-01

Understanding the wing twist of the active aeroelastic wing (AAW) F/A-18 aircraft is a fundamental research objective for the program and offers numerous benefits. In order to clearly understand the wing flexibility characteristics, a model was created to predict real-time wing twist. A reliable twist model allows the prediction of twist for flight simulation, provides insight into aircraft performance uncertainties, and assists with computational fluid dynamic and aeroelastic issues. The left wing of the aircraft was heavily instrumented during the first phase of the active aeroelastic wing program allowing deflection data collection. Traditional data processing steps were taken to reduce flight data, and twist predictions were made using linear regression techniques. The model predictions determined a consistent linear relationship between the measured twist and aircraft parameters, such as surface positions and aircraft state variables. Error in the original model was reduced in some cases by using a dynamic pressure-based assumption. This technique produced excellent predictions for flight between the standard test points and accounted for nonlinearities in the data. This report discusses data processing techniques and twist prediction validation, and provides illustrative and quantitative results.

Twist Model Development and Results From the Active Aeroelastic Wing F/A-18 Aircraft

NASA Technical Reports Server (NTRS)

Lizotte, Andrew; Allen, Michael J.

2005-01-01

Understanding the wing twist of the active aeroelastic wing F/A-18 aircraft is a fundamental research objective for the program and offers numerous benefits. In order to clearly understand the wing flexibility characteristics, a model was created to predict real-time wing twist. A reliable twist model allows the prediction of twist for flight simulation, provides insight into aircraft performance uncertainties, and assists with computational fluid dynamic and aeroelastic issues. The left wing of the aircraft was heavily instrumented during the first phase of the active aeroelastic wing program allowing deflection data collection. Traditional data processing steps were taken to reduce flight data, and twist predictions were made using linear regression techniques. The model predictions determined a consistent linear relationship between the measured twist and aircraft parameters, such as surface positions and aircraft state variables. Error in the original model was reduced in some cases by using a dynamic pressure-based assumption and by using neural networks. These techniques produced excellent predictions for flight between the standard test points and accounted for nonlinearities in the data. This report discusses data processing techniques and twist prediction validation, and provides illustrative and quantitative results.

Coexistence of twisted and untwisted crystals: An impurity/structural order model with implications for agate patterns

USGS Publications Warehouse

Comer, J.; Ortoleva, P.

2007-01-01

Coexistence of twisted and untwisted crystals is explained via a model that accounts for the coupling of the entropic and energetic effects of impurities and a supra-lattice-scale structural order parameter. It is shown that twisted impure crystals can be in equilibrium with untwisted purer ones. The model explains how coexistence can occur in agates and other systems under hydrostatic stress. The model implies that untwisted crystals grown under one set of conditions could undergo a phase separation that, when accompanied by an imposed compositional gradient, leads to commonly observed, alternating bands of twisted and untwisted crystals and, when occurring in the absence of an external gradient, mossy patterns of crystal texture can emerge. This phenomenon is not related to anisotropic applied stress. Rather coexistence is a consequence of a compositional segregation/twist phase transition. Since twist coexistence is a compositional equilibrium, it arises from the exchange between bulk phases; hence, the detailed nature of the atomic structure within an interface between twisted and untwisted zones is not relevant. The approach places crystal-twist phenomena within the theory of order/disorder phase transitions.

Operator constraints for twist-3 functions and Lorentz invariance properties of twist-3 observables

DOE PAGES

Kanazawa, Koichi; Pitonyak, Daniel; Koike, Yuji; ...

2016-03-14

We investigate the behavior under Lorentz transformations of perturbative coefficient functions in a collinear twist-3 formalism relevant for high-energy observables including transverse polarization of hadrons. We argue that those perturbative coefficient functions can, a priori, acquire quite different yet Lorentz-invariant forms in various frames. This somewhat surprising difference can be traced back to a general dependence of the perturbative coefficient functions on light cone vectors which are introduced by the twist-3 factorization formulas and which are frame-dependent. One can remove this spurious frame dependence by invoking so-called Lorentz invariance relations (LIRs) between twist-3 parton correlation functions. Some of those relationsmore » for twist-3 distribution functions were discussed in the literature before. In this paper we derive the corresponding LIRs for twist-3 fragmentation functions. We explicitly demonstrate that these LIRs remove the light cone vector dependence by considering transverse spin observables in the single-inclusive production of hadrons in lepton-nucleon collisions, ℓN→hX. Furthermore, with the LIRs in hand, we also show that twist-3 observables in general can be written solely in terms of three-parton correlation functions.« less

Experimental Investigation of the Electronic Properties of Twisted Bilayer Graphene by STM and STS

NASA Astrophysics Data System (ADS)

Yin, Longjing; Qiao, Jiabin; Wang, Wenxiao; Zuo, Weijie; He, Lin

The electronic properties of graphene multilayers depend sensitively on their stacking order. A twisted angle is treated as a unique degree of freedom to tune the electronic properties of graphene system. Here we study electronic structures of the twisted bilayers by scanning tunneling microscopy (STM) and spectroscopy (STS). We demonstrate that the interlayer coupling strength affects both the Van Hove singularities and the Fermi velocity of twisted bilayers dramatically. This removes the discrepancy about the Fermi velocity renormalization in the twisted bilayers and provides a consistent interpretation of all current data. Moreover, we report the experimental evidence for non-Abelian gauge potentials in twisted graphene bilayers by STM and STS. At a magic twisted angle, about 1.11°, a pronounced sharp peak is observed in the tunnelling spectra due to the action of the non-Abelian gauge fields. Because of the effective non-Abelian gauge fields, the rotation angle could transfer the charge carriers in the twisted bilayers from massless Dirac fermions into well localized electrons, or vice versa, efficiently. This provides a new route to tune the electronic properties of graphene systems, which will be essential in future graphene nanoelectronics.

An analysis of rotor blade twist variables associated with different Euler sequences and pretwist treatments

NASA Technical Reports Server (NTRS)

Alkire, K.

1984-01-01

A nonlinear analysis which is necessary to adequately model elastic helicopter rotor blades experiencing moderately large deformations was examined. The analysis must be based on an appropriate description of the blade's deformation geometry including elastic bending and twist. Built-in pretwist angles complicate the deformation process ant its definition. Relationships between the twist variables associated with different rotation sequences and corresponding forms of the transformation matrix are lasted. Relationships between the twist variables associated with first, the pretwist combined with the deformation twist are included. Many of the corresponding forms of the transformation matrix for the two cases are listed. It is shown that twist variables connected with the combined twist treatment are related to those where the pretwist is applied initially. A method to determine the relationships and some results are outlined. A procedure to evaluate the transformation matrix that eliminates the Eulerlike sequence altogether is demonstrated. The resulting form of the transformation matrix is unaffected by rotation sequence or pretwist treatment.

Aeroelastic Analysis of Helicopter Rotor Blades Incorporating Anisotropic Piezoelectric Twist Actuation

NASA Technical Reports Server (NTRS)

Wilkie, W. Keats; Belvin, W. Keith; Park, K. C.

1996-01-01

A simple aeroelastic analysis of a helicopter rotor blade incorporating embedded piezoelectric fiber composite, interdigitated electrode blade twist actuators is described. The analysis consists of a linear torsion and flapwise bending model coupled with a nonlinear ONERA based unsteady aerodynamics model. A modified Galerkin procedure is performed upon the rotor blade partial differential equations of motion to develop a system of ordinary differential equations suitable for dynamics simulation using numerical integration. The twist actuation responses for three conceptual fullscale blade designs with realistic constraints on blade mass are numerically evaluated using the analysis. Numerical results indicate that useful amplitudes of nonresonant elastic twist, on the order of one to two degrees, are achievable under one-g hovering flight conditions for interdigitated electrode poling configurations. Twist actuation for the interdigitated electrode blades is also compared with the twist actuation of a conventionally poled piezoelectric fiber composite blade. Elastic twist produced using the interdigitated electrode actuators was found to be four to five times larger than that obtained with the conventionally poled actuators.

An aeroelastic analysis of helicopter rotor blades incorporating piezoelectric fiber composite twist actuation

NASA Technical Reports Server (NTRS)

Wilkie, W. Keats; Park, K. C.

1996-01-01

A simple aeroelastic analysis of a helicopter rotor blade incorporating embedded piezoelectric fiber composite, interdigitated electrode blade twist actuators is described. The analysis consist of a linear torsion and flapwise bending model coupled with a nonlinear ONERA based unsteady aerodynamics model. A modified Galerkin procedure is performed upon the rotor blade partial differential equations of motion to develop a system of ordinary differential equations suitable for numerical integration. The twist actuation responses for three conceptual full-scale blade designs with realistic constraints on blade mass are numerically evaluated using the analysis. Numerical results indicate that useful amplitudes of nonresonant elastic twist, on the order of one to two degrees, are achievable under one-g hovering flight conditions for interdigitated electrode poling configurations. Twist actuation for the interdigitated electrode blades is also compared with the twist actuation of a conventionally poled piezoelectric fiber composite blade. Elastic twist produced using the interdigitated electrode actuators was found to be four to five times larger than that obtained with the conventionally poled actuators.

Immediate Effects of Ankle Balance Taping with Kinesiology Tape for Amateur Soccer Players with Lateral Ankle Sprain: A Randomized Cross-Over Design

PubMed Central

Kim, Myoung Kwon; Shin, Young Jun

2017-01-01

Background The objective of this study was to investigate the immediate effect on gait function when ankle balance taping is applied to amateur soccer players with lateral ankle sprain. Material/Methods A cross-over randomized design was used. Twenty-two soccer players with an ankle sprain underwent 3 interventions in a random order. Subjects were randomly assigned to ankle balance taping, placebo taping, and no taping groups. The assessment was performed using the GAITRite portable walkway system, which records the location and timing of each footfall during ambulation. Results Significant differences were found in the velocity, step length, stride length, and H-H base support among the 3 different taping methods (p<0.05). The ankle balance taping group showed significantly greater velocity, step length, and stride length in comparison to the placebo and no taping group. The ankle balance taping group showed a statistically significant decrease (p<0.05) in the H-H base support compared to the placebo and no taping groups, and the placebo group showed significantly greater velocity in comparison to the no taping group (p<0.05). Conclusions We conclude that ankle balance taping that uses kinesiology tape instantly increased the walking ability of amateur soccer players with lateral ankle sprain. Therefore, ankle balance taping is a useful alternative to prevent and treat ankle sprain of soccer players. PMID:29158472

Electrostatic contribution to twist rigidity of DNA.

PubMed

Mohammad-Rafiee, Farshid; Golestanian, Ramin

2004-06-01

The electrostatic contribution to the twist rigidity of DNA is studied, and it is shown that the Coulomb self-energy of the double-helical sugar-phosphate backbone makes a considerable contribution-the electrostatic twist rigidity of DNA is found to be C(elec) approximately 5 nm, which makes up about 7% of its total twist rigidity ( C(DNA) approximately 75 nm). The electrostatic twist rigidity is found, however, to depend only weakly on the salt concentration, because of a competition between two different screening mechanisms: (1) Debye screening by the salt ions in the bulk, and (2) structural screening by the periodic charge distribution along the backbone of the helical polyelectrolyte. It is found that, depending on the parameters, the electrostatic contribution to the twist rigidity could stabilize or destabilize the structure of a helical polyelectrolyte.

Updated Systematic Review and Meta-analysis of the Comparative Data on Colposuspensions, Pubovaginal Slings, and Midurethral Tapes in the Surgical Treatment of Female Stress Urinary Incontinence.

PubMed

Fusco, Ferdinando; Abdel-Fattah, Mohamed; Chapple, Christopher R; Creta, Massimiliano; La Falce, Sabrina; Waltregny, David; Novara, Giacomo

2017-10-01

Retropubic (RP-TVT) and transobturator miurethral (TO-TVT) midurethral sling (MUS) are popular surgical treatments for female stress urinary incontinence. The long-term efficacy and safety of the procedures is still a topic of intense clinical research and several randomised controlled trials (RCTs) have been published in the last years OBJECTIVE: To evaluate the efficacy and safety of MUS compared with other surgical treatments for female stress urinary incontinence. A systematic review and meta-analysis of the literature was performed using the Medline, Scopus, and Web of Science databases to update our previously published analyses. Twenty-eight RCTs were identified. In total, the meta-analyses included 15 855 patients. Patients receiving MUS had significantly higher overall (odds ratio [OR]: 0.59, p=0.0003) and objective (OR: 0.51, p=0.001) cure rates than those receiving Burch colposuspension. Patients undergoing MUS and pubovaginal slings had similar cure rates. Patients treated with RT-TVT had higher subjective (OR: 0.83, p=0.03) and objective (OR: 0.82, p=0.01) cure rates than those receiving TO-TVT. However, the latter had a lower risk of intraoperative bladder or vaginal perforation (OR: 2.4, p=0.0002), pelvic haematoma (OR: 2.61, p=0.002), urinary tract infections (OR: 1.31, p=0.04) and voiding lower urinary tract symptoms (OR: 1.66, p=0.002). Sensitivity analyses limited to RCTs with follow-up durations >60 mo demonstrated similar outcomes for RP-TVT and TO-TVT. No significant differences in efficacy were identified comparing inside-to-out and outside-to-in TO-TVT but vaginal perforations were less common with the former (OR: 0.21, p=0.0002). The present analysis confirms the superiority of MUS over Burch colposuspension. The studies comparing insertion of RT-TVT and TO-TVT showed higher subjective and objective cure rates for the RP-TVT but at the cost of higher risks of some complications and voiding lower urinary tract symptoms. Efficacy of inside-out and outside-in techniques of TO-TVT insertion was similar, although the risk of vaginal perforation was lower in the inside-to-out TO-TVT. Retropubic and transobturator midurethral slings are a popular treatment for female stress urinary incontinence. The available literature suggest that those slings are either more effective or safer than other older surgical procedures. Retropubic tapes are followed with slightly higher continence rates as compared with the transobturator tapes but are associated with higher risk of intra- and postoperative complications. Copyright © 2017 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Effect of twist on transverse impact response of ballistic fiber yarns

DOE PAGES

Song, Bo; Lu, Wei -Yang

2015-06-15

A Hopkinson bar was employed to conduct transverse impact testing of twisted Kevlar KM2 fiber yarns at the same impact speed. The speed of Euler transverse wave generated by the impact was measured utilizing a high speed digital camera. The study included fiber yarns twisted by different amounts. The Euler transverse wave speed was observed to increase with increasing amount of twist of the fiber yarn, within the range of this investigation. As a result, the higher transverse wave speeds in the more twisted fiber yarns indicate better ballistic performance in soft body armors for personal protection.

PHOTOELECTRIC CONTROL FOR TAPE POSITIONING

DOEpatents

Woody, J.W. Jr.

1961-07-25

A control system is described for producing control impulses which may be used to start, stop, and position a magnetic tape with respect to a transducer, and to locate discrete areas on the tape. Means are provided for positive identification of data blocks, exact positioning of the tape under the magnetic head, drive in either direction, accurate skip-over of imperfect regions of the tape, stopping the tape if equipment malfunction results in a failure to detect the block-identifying signals, and starting and stopping those parts of the tape between of the tape drive clutches.

The Effect of Patellar Taping on Squat Depth and the Perception of Pain in People with Anterior Knee Pain

PubMed Central

Clifford, Amanda M.; Harrington, Elaine

Patellar taping is a treatment adjunct commonly used in the management of anterior knee pain. The aim of this cross sectional study was to investigate the effects of medial glide patellar taping on sagittal plane lower-limb joint kinematics and knee pain during a unilateral squat in a symptomatic population complaining of anterior knee pain. Ten participants with a history of unilateral or bilateral anterior knee pain were included in the study. Subjects were required to squat on the symptomatic leg under three conditions: placebo tape, patellar tape and no tape. Kinematic data was recorded using the CODA mpx64 motion analysis system and subjects’ pain was assessed using the Numerical Rating Scale. Patellar taping resulted in a significantly greater single-legged squat depth compared to placebo tape (p=0.008) and no tape (p=0.001) and a statistically significant reduction in pain during a squat compared to placebo tape (p=0.001) or no tape (p=0.001). Significant differences were not identified for maximum knee flexion in the patella taping compared to the no tape condition. This study may have significant clinical implications as participants reported less pain and alterations in sagittal plane movement following the application of patellar tape. PMID:24146711

Development of a 500 kVA-class oxide-superconducting power transformer operated at liquid-nitrogen temperature

NASA Astrophysics Data System (ADS)

Funaki, K.; Iwakuma, M.; Kajikawa, K.; Takeo, M.; Suehiro, J.; Hara, M.; Yamafuji, K.; Konno, M.; Kasagawa, Y.; Okubo, K.; Yasukawa, Y.; Nose, S.; Ueyama, M.; Hayashi, K.; Sato, K.

We have designed and constructed a 500 kVA-class oxide-superconducting power transformer. The windings are cooled by liquid nitrogen or subcooled nitrogen in a G-FRP cryostat of 785 mm in diameter and 1210 mm in height, that has a room-temperature space for an iron core with the diameter of 314 mm. The primary and secondary windings are three-strand and six-strand parallel conductors of a Bi-2223 multifilamentary tape with silver sheath, respectively. The strand 0.22 mm thick and 3.5 mm wide has 61 filaments with no twisting. The ratio of superconductor is 0.284. In the parallel conductors, the strands are transposed five times in each layer for a uniform current distribution among them. It was proved that the transformer has the rated capacity of 500 kVA by means of two-h short-circuit test and half-h no-load test in liquid nitrogen of 77 K. The efficiency is estimated as 99.1% from a core loss of 2.3 kW and a thermal load of 2.2 kW in coolant. The latter is composed of AC losses in windings and heat leakage from the cryostat and current leads, and is multiplied by a refrigeration penalty of liquid nitrogen, 20. Load test was also performed up to 500 kVA. The transformer was furthermore operated in subcooled nitrogen at 66 K with no quenching up to a critical level, that is equivalent to 800 kVA. The efficiency estimated was improved to 99.3% in subcooled nitrogen. Measured a.c. loss in both windings are well explained by a theoretical prediction with the "critical state model". We also discuss prospective applications of the parallel conductors composed of advanced HTS multifilamentary tapes to a.c. windings with large current capacity.

Combined detection of Twist1, Snail1 and squamous cell carcinoma antigen for the prognostic evaluation of invasion and metastasis in cervical squamous cell carcinoma.

PubMed

Yang, Huilun; Hu, Haiyang; Gou, Yanling; Hu, Yuhong; Li, Hui; Zhao, Hongwei; Wang, Beidi; Li, Peiling; Zhang, Zongfeng

2018-04-01

Cervical cancer is one of the most common malignant tumours of the female reproductive system, ranking second only to breast cancer in morbidity worldwide. Essential features of the progression of cervical cancer are invasion and metastasis, which are closely related to disease prognosis and mortality rate. At the present time there is no effective method to evaluate cancer invasion and metastasis before surgery. Here we report our study on molecular changes in biopsy tissue for the prognostic evaluation of cancer invasion and metastasis. Expression of the epithelial-mesenchymal transition-inducing transcription factors Twist1 and Snail1 was detected by immunohistochemistry in 32 normal, 36 low-grade squamous intraepithelial neoplasia (LSIL), 54 high-grade squamous intraepithelial neoplasia (HSIL) and 320 cervical squamous cell carcinoma (CSCC) samples. The correlation between the expression of Twist1, Snail1 and squamous cell carcinoma antigen (SCCA) in CSCC tissues and clinical pathology results was evaluated. A transwell migration and invasion assay was used to explore the roles of Twist1 and Snail1 in the invasion of cancer cells. Lymph node metastasis and lymphovascular space invasion (LVSI) rates for the following groups were analysed: SCCA(+) group, Twist1(+) group, Snail1(+) group, Twist1(+)Snail1(+)group, Twist1(+)SCCA(+)group, Snail1(+)SCCA(+)group and Twist1(+)Snail1(+)SCCA(+) group. The expression of Twist1 and Snail1 was significantly upregulated in HSIL and CSCC (p < 0.05). Twist1 and Snail1 expression levels were associated with LVSI, lymph node metastasis and histological grade (p < 0.05) but not with age or FIGO stage (p > 0.05). The expression of SCCA was associated with LVSI, lymph node metastasis, FIGO stage and histological grade (p < 0.05) but not with age (p > 0.05). Twist1 was an independent factor contributing to the invasion ability of cervical cancer cells. In addition, the positive rate of lymph node metastasis and LVSI was higher in the Twist1(+)Snail1(+)SCCA(+) group than in the SCCA(+) group, Twist1(+) group and Snail1(+) group, respectively (p < 0.05). Combined detection of Twist1 and Snail1 in SCCA-positive biopsy specimens may be a potential method for evaluating the invasion and metastasis of CSCC prior to surgery.

Anisotropic piezoelectric twist actuation of helicopter rotor blades: Aeroelastic analysis and design optimization

NASA Astrophysics Data System (ADS)

Wilkie, William Keats

1997-12-01

An aeroelastic model suitable for control law and preliminary structural design of composite helicopter rotor blades incorporating embedded anisotropic piezoelectric actuator laminae is developed. The aeroelasticity model consists of a linear, nonuniform beam representation of the blade structure, including linear piezoelectric actuation terms, coupled with a nonlinear, finite-state unsteady aerodynamics model. A Galerkin procedure and numerical integration in the time domain are used to obtain a soluti An aeroelastic model suitable for control law and preliminary structural design of composite helicopter rotor blades incorporating embedded anisotropic piezoelectric actuator laminae is developed. The aeroelasticity model consists of a linear, nonuniform beam representation of the blade structure, including linear piezoelectric actuation terms, coupled with a nonlinear, finite-state unsteady aerodynamics model. A Galerkin procedure and numerical integration in the time domain are used to obtain amited additional piezoelectric material mass, it is shown that blade twist actuation approaches which exploit in-plane piezoelectric free-stain anisotropies are capable of producing amplitudes of oscillatory blade twisting sufficient for rotor vibration reduction applications. The second study examines the effectiveness of using embedded piezoelectric actuator laminae to alleviate vibratory loads due to retreating blade stall. A 10 to 15 percent improvement in dynamic stall limited forward flight speed, and a 5 percent improvement in stall limited rotor thrust were numerically demonstrated for the active twist rotor blade relative to a conventional blade design. The active twist blades are also demonstrated to be more susceptible than the conventional blades to dynamic stall induced vibratory loads when not operating with twist actuation. This is the result of designing the active twist blades with low torsional stiffness in order to maximize piezoelectric twist authority. Determining the optimum tradeoff between blade torsional stiffness and piezoelectric twist actuation authority is the subject of the third study. For this investigation, a linearized hovering-flight eigenvalue analysis is developed. Linear optimal control theory is then utilized to develop an optimum active twist blade design in terms of reducing structural energy and control effort cost. The forward flight vibratory loads characteristics of the torsional stiffness optimized active twist blade are then examined using the nonlinear, forward flight aeroelastic analysis. The optimized active twist rotor blade is shown to have improved passive and active vibratory loads characteristics relative to the baseline active twist blades.

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

Abushakra, Bass

The aging tests conducted so far showed that duct tape tends to degrade in its performance as the joint it is applied to requires a geometrical description of a higher number of space dimensions (1-D, 2-D, 3-D). One-dimensional joints are the easiest to seal with duct tape, and thus the least to experience failure. Two-dimensional joints, such as the flexible duct core-to-collar joints tested in this study, are less likely to fail than three-dimensional collar-to-plenum joints, as the shrinkage could have a positive effect in tightening the joint. Three-dimensional joints are the toughest to seal and the most likely tomore » experience failure. The 2-D flexible duct core-to-collar joints passed the six-month period of the aging test in terms of leakage, but with the exception of the foil-butyl tape, showed degradation in terms hardening, brittleness, partial peeling, shrinkage, wrinkling, delamination of the tape layers, flaking, cracking, bubbling, oozing and discoloration. The baking test results showed that the failure in the duct tape joints could be attributed to the type of combination of the duct tape and the material it is applied to, as the duct tape behaves differently with different substrates. Overall, the foil-butyl tape (Tape 4) had the best results, while the film tape (Tape 3) showed the most deterioration. The conventional duct tapes tested (Tape 1 and Tape 2) were between these two extremes, with Tape 2 performing better than Tape 1. Lastly, we found that plastic straps became discolored and brittle during the tests, and a couple of straps broke completely. Therefore, we recommend that clamping the duct-taped flexible core-to-collar joints should be done with metallic adjustable straps.« less

Twisting failure of centrally loaded open-section columns in the elastic range

NASA Technical Reports Server (NTRS)

Kappus, Robert

1938-01-01

In the following report a complete theory of twisting failure by the energy method is developed, based on substantially the same assumptions as those employed by Wagner and Bleich. Problems treated in detail are: the stress and strain condition under St. Venant twist and in twist with axial constraint; the concept of shear center and the energy method for problems of elastic stability.

On the twists of interplanetary magnetic flux ropes observed at 1 AU

NASA Astrophysics Data System (ADS)

Wang, Yuming; Zhuang, Bin; Hu, Qiang; Liu, Rui; Shen, Chenglong; Chi, Yutian

2016-10-01

Magnetic flux ropes (MFRs) are one kind of fundamental structures in the solar/space physics and involved in various eruption phenomena. Twist, characterizing how the magnetic field lines wind around a main axis, is an intrinsic property of MFRs, closely related to the magnetic free energy and stableness. Although the effect of the twist on the behavior of MFRs had been widely studied in observations, theory, modeling, and numerical simulations, it is still unclear how much amount of twist is carried by MFRs in the solar atmosphere and in heliosphere and what role the twist played in the eruptions of MFRs. Contrasting to the solar MFRs, there are lots of in situ measurements of magnetic clouds (MCs), the large-scale MFRs in interplanetary space, providing some important information of the twist of MFRs. Thus, starting from MCs, we investigate the twist of interplanetary MFRs with the aid of a velocity-modified uniform-twist force-free flux rope model. It is found that most of MCs can be roughly fitted by the model and nearly half of them can be fitted fairly well though the derived twist is probably overestimated by a factor of 2.5. By applying the model to 115 MCs observed at 1 AU, we find that (1) the twist angles of interplanetary MFRs generally follow a trend of about 0.6l/R radians, where l/R is the aspect ratio of a MFR, with a cutoff at about 12π radians AU-1, (2) most of them are significantly larger than 2.5π radians but well bounded by 2l/R radians, (3) strongly twisted magnetic field lines probably limit the expansion and size of MFRs, and (4) the magnetic field lines in the legs wind more tightly than those in the leading part of MFRs. These results not only advance our understanding of the properties and behavior of interplanetary MFRs but also shed light on the formation and eruption of MFRs in the solar atmosphere. A discussion about the twist and stableness of solar MFRs are therefore given.

Use of binaural beat tapes for treatment of anxiety: a pilot study of tape preference and outcomes.

PubMed

Le Scouarnec, R P; Poirier, R M; Owens, J E; Gauthier, J; Taylor, A G; Foresman, P A

2001-01-01

Recent studies and anecdotal reports suggest that binaural auditory beats can affect mood, performance on vigilance tasks, and anxiety. To determine whether mildly anxious people would report decreased anxiety after listening daily for 1 month to tapes imbedded with tones that create binaural beats, and whether they would show a definite tape preference among 3 tapes. A 1-group pre-posttest pilot study. Patients' homes. A volunteer sample of 15 mildly anxious patients seen in the Clinique Psyché, Montreal, Quebec. Participants were asked to listen at least 5 times weekly for 4 weeks to 1 or more of 3 music tapes containing tones that produce binaural beats in the electroencephalogram delta/theta frequency range. Participants also were asked to record tape usage, tape preference, and anxiety ratings in a journal before and after listening to the tape or tapes. Anxiety ratings before and after tape listening, pre- and post-study State-Trait Anxiety Inventory scores, and tape preferences documented in daily journals. Listening to the binaural beat tapes resulted in a significant reduction in the anxiety score reported daily in patients' diaries. The number of times participants listened to the tapes in 4 weeks ranged from 10 to 17 (an average of 1.4 to 2.4 times per week) for approximately 30 minutes per session. End-of-study tape preferences indicated that slightly more participants preferred tape B, with its pronounced and extended patterns of binaural beats, over tapes A and C. Changes in pre- and posttest listening State-Trait Anxiety Inventory scores trended toward a reduction of anxiety, but these differences were not statistically significant. Listening to binaural beat tapes in the delta/theta electroencephalogram range may be beneficial in reducing mild anxiety. Future studies should account for music preference among participants and include age as a factor in outcomes, incentives to foster tape listening, and a physiologic measure of anxiety reduction. A controlled trial that includes binaural beat tapes as an adjunctive treatment to conventional therapy for mild anxiety may be warranted.

Aeromechanical Evaluation of Smart-Twisting Active Rotor

NASA Technical Reports Server (NTRS)

Lim, Joon W.; Boyd, D. Douglas, Jr.; Hoffman, Frauke; van der Wall, Berend G.; Kim, Do-Hyung; Jung, Sung N.; You, Young H.; Tanabe, Yasutada; Bailly, Joelle; Lienard, Caroline;

41 CFR 101-26.508-2 - Requisitioning data processing tape not available from Federal Supply Schedule contracts.

Code of Federal Regulations, 2013 CFR

2013-07-01

... contracts. (a) Requisitions for types of EDP tape and instrumentation tape (wide and intermediate band... is located. (b) Requisitions for all types of EDP tape and instrumentation tape (wide and... and $5,000 for instrumentation tape. However, regardless of the amount involved (including...

Effect of Rotor- and Stator-Blade Modifications on Surge Performance of an 11-Stage Axial-Flow Compressor. I - Original Production Compressor of XJ40-WE-6 Engine

NASA Technical Reports Server (NTRS)

Finger, Harold B.; Essig, Robert H.; Conrad, E. William

1952-01-01

An investigation to increase the compressor surge-limit pressure ratio of the XJ40-WE-6 turbojet engine at high equivalent speeds was conducted at the NACA Lewis altitude wind tunnel. This report evaluates the compressor modifications which were restricted to (1) twisting rotor blades (in place) to change blade section angles and (2) inserting new stator diaphragms with different blade angles. Such configuration changes could be incorporated quickly and easily in existing engines at overhaul depots. It was found that slight improvements in the compressor surge limit were possible by compressor blade adjustment. However, some of the modifications also reduced the engine air flow and hence penalized the thrust. The use of a mixer assembly at the compressor outlet improved the surge limit with no appreciable thrust penalty.

Wandering spleen with gastric volvulus and intestinal non-rotation in an adult male patient

PubMed Central

Kohda, Eiichi; Iizuka, Yuo; Nagamoto, Masashi; Ishii, Tomotaka; Saida, Yoshihisa; Shimizu, Norikazu; Gomi, Tatsuya

2013-01-01

We report an extremely rare case of wandering spleen (WS) complicated with gastric volvulus and intestinal non-rotation in a male adult. A 22-year-old man who had been previously treated for Wilson disease was admitted with severe abdominal pain. Radiological findings showed WS in the midline of the pelvic area. The stomach was mesenteroaxially twisted and intestinal non-rotation was observed. Radiology results did not show any evidence of splenic or gastrointestinal (GI) infarction. Elective emergency laparoscopy confirmed WS and intestinal non-rotation; however, gastric volvulus was not observed. It was suspected that the stomach had untwisted when gastric and laparoscopic tubes were inserted. Surgery is strongly recommended for WS because of the high risk of serious complications; however, some asymptomatic adult patients are still treated conservatively, such as the patient in this study. The present case is reported with reference to the literature. PMID:24349711

Wandering spleen with gastric volvulus and intestinal non-rotation in an adult male patient.

PubMed

Ooka, Minako; Kohda, Eiichi; Iizuka, Yuo; Nagamoto, Masashi; Ishii, Tomotaka; Saida, Yoshihisa; Shimizu, Norikazu; Gomi, Tatsuya

2013-01-01

We report an extremely rare case of wandering spleen (WS) complicated with gastric volvulus and intestinal non-rotation in a male adult. A 22-year-old man who had been previously treated for Wilson disease was admitted with severe abdominal pain. Radiological findings showed WS in the midline of the pelvic area. The stomach was mesenteroaxially twisted and intestinal non-rotation was observed. Radiology results did not show any evidence of splenic or gastrointestinal (GI) infarction. Elective emergency laparoscopy confirmed WS and intestinal non-rotation; however, gastric volvulus was not observed. It was suspected that the stomach had untwisted when gastric and laparoscopic tubes were inserted. Surgery is strongly recommended for WS because of the high risk of serious complications; however, some asymptomatic adult patients are still treated conservatively, such as the patient in this study. The present case is reported with reference to the literature.

InGaP Heterojunction Barrier Solar Cells

NASA Technical Reports Server (NTRS)

Welser, Roger E. (Inventor)

2014-01-01

A new solar cell structure called a heterojunction barrier solar cell is described. As with previously reported quantum-well and quantum-dot solar cell structures, a layer of narrow band-gap material, such as GaAs or indium-rich InGaP, is inserted into the depletion region of a wide band-gap PN junction. Rather than being thin, however, the layer of narrow band-gap material is about 400-430 nm wide and forms a single, ultrawide well in the depletion region. Thin (e.g., 20-50 nm), wide band-gap InGaP barrier layers in the depletion region reduce the diode dark current. Engineering the electric field and barrier profile of the absorber layer, barrier layer, and p-type layer of the PN junction maximizes photogenerated carrier escape. This new twist on nanostructured solar cell design allows the separate optimization of current and voltage to maximize conversion efficiency.

Exchange coupling and NOL magnetism consideration in Co 1-xFe x specular spin-valves

NASA Astrophysics Data System (ADS)

Doi, M.; Izumi, M.; Abe, Y.; Fukuzawa, H.; Fuke, H. N.; Iwasaki, H.; Sahashi, M.

2005-02-01

To confirm the origin of the exchange coupling through the nano-oxide layer (NOL), the detailed analyses of the magnetization curve and the temperature dependence on magnetization for the Co1-xFex-NOL samples with various oxidation processes are investigated. The field cooling effect is observed for NOL-inserted samples, which suggests the existence of the antiferromagnetic (AFM) component in the NOL. The characteristic temperature (blocking temperature) increases with increase in the Fe content for Co1-xFex(x=0.08,0.17,0.26)-NOL. These results support that NOL pinning appears higher than room temperature. Further, the twisted coupling through the NOL observed for the Co0.50Fe0.50-NOL is discussed from the viewpoint of the magnetic roughness due to the ferrimagnetic nature of the very thin NOL in specular spin valve (SPSV).

Donaldson-Witten theory and indefinite theta functions

NASA Astrophysics Data System (ADS)

Korpas, Georgios; Manschot, Jan

2017-11-01

We consider partition functions with insertions of surface operators of topologically twisted N=2 , SU(2) supersymmetric Yang-Mills theory, or Donaldson-Witten theory for short, on a four-manifold. If the metric of the compact four-manifold has positive scalar curvature, Moore and Witten have shown that the partition function is completely determined by the integral over the Coulomb branch parameter a, while more generally the Coulomb branch integral captures the wall-crossing behavior of both Donaldson polynomials and Seiberg-Witten invariants. We show that after addition of a \\overlineQ -exact surface operator to the Moore-Witten integrand, the integrand can be written as a total derivative to the anti-holomorphic coordinate ā using Zwegers' indefinite theta functions. In this way, we reproduce Göttsche's expressions for Donaldson invariants of rational surfaces in terms of indefinite theta functions for any choice of metric.

Nonlinear SVM-DTC for induction motor drive using input-output feedback linearization and high order sliding mode control.

PubMed

Ammar, Abdelkarim; Bourek, Amor; Benakcha, Abdelhamid

2017-03-01

This paper presents a nonlinear Direct Torque Control (DTC) strategy with Space Vector Modulation (SVM) for an induction motor. A nonlinear input-output feedback linearization (IOFL) is implemented to achieve a decoupled torque and flux control and the SVM is employed to reduce high torque and flux ripples. Furthermore, the control scheme performance is improved by inserting a super twisting speed controller in the outer loop and a load torque observer to enhance the speed regulation. The combining of dual nonlinear strategies ensures a good dynamic and robustness against parameters variation and disturbance. The system stability has been analyzed using Lyapunov stability theory. The effectiveness of the control algorithm is investigated by simulation and experimental validation using Matlab/Simulink software with real-time interface based on dSpace 1104. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Annealing effect on the magnetic induced austenite transformation in polycrystalline freestanding Ni-Co-Mn-In films produced by co-sputtering

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

Crouïgneau, G., E-mail: guillaume.crouigneau@neel.cnrs.fr; Univ. Grenoble Alpes, CRETA, F-38000 Grenoble; CNRS, Inst. NEEL, F-38000 Grenoble

2015-01-21

Ni-Co-Mn-In freestanding films, with a magneto-structural transformation at room temperature were successfully produced by co-sputtering and post-annealing methods leading to film composition mastering. For a post-annealing temperature of 700 °C, the phase transformation occurs slightly above room temperature, with a twisted martensitic microstructure phase observed at 300 K by Field Emission Scanning Electron Microscopy. Magnetization measurements on a polycrystalline film showed a phase transformation from a weakly magnetic martensite to a magnetic austenite phase. Moreover, an inverse magnetocaloric effect with an entropy variation of 4 J/kg K under 5 T was also measured. A simple magneto-actuation experiment based on the magnetic induced austenite transformation wasmore » also successfully completed. The possibility to insert such films in microsystems is clearly demonstrated in this work.« less

Structure and conformational states of the bovine mitochondrial ATP synthase by cryo-EM.

PubMed

Zhou, Anna; Rohou, Alexis; Schep, Daniel G; Bason, John V; Montgomery, Martin G; Walker, John E; Grigorieff, Nikolaus; Rubinstein, John L

2015-10-06

Adenosine triphosphate (ATP), the chemical energy currency of biology, is synthesized in eukaryotic cells primarily by the mitochondrial ATP synthase. ATP synthases operate by a rotary catalytic mechanism where proton translocation through the membrane-inserted FO region is coupled to ATP synthesis in the catalytic F1 region via rotation of a central rotor subcomplex. We report here single particle electron cryomicroscopy (cryo-EM) analysis of the bovine mitochondrial ATP synthase. Combining cryo-EM data with bioinformatic analysis allowed us to determine the fold of the a subunit, suggesting a proton translocation path through the FO region that involves both the a and b subunits. 3D classification of images revealed seven distinct states of the enzyme that show different modes of bending and twisting in the intact ATP synthase. Rotational fluctuations of the c8-ring within the FO region support a Brownian ratchet mechanism for proton-translocation-driven rotation in ATP synthases.

Metallographic autopsies of full-scale ITER prototype cable-in-conduit conductors after full cyclic testing in SULTAN: III. The importance of strand surface roughness in long twist pitch conductors

DOE PAGES

Sanabria, Charlie; Lee, Peter J.; Starch, William; ...

2016-05-31

As part of the ITER conductor qualification process, 3 m long Cable-in-Conduit Conductors (CICCs) were tested at the SULTAN facility under conditions simulating ITER operation so as to establish the current sharing temperature, T cs, as a function of multiple full Lorentz force loading cycles. After a comprehensive evaluation of both the Toroidal Field (TF) and the Central Solenoid (CS) conductors, it was found that T cs degradation was common in long twist pitch TF conductors while short twist pitch CS conductors showed some T cs increase. However, one kind of TF conductors containing superconducting strand fabricated by the Bochvarmore » Institute of Inorganic Materials (VNIINM) avoided T cs degradation despite having long twist pitch. In our earlier metallographic autopsies of long and short twist pitch CS conductors, we observed a substantially greater transverse strand movement under Lorentz force loading for long twist pitch conductors, while short twist pitch conductors had negligible transverse movement. With help from the literature, we concluded that the transverse movement was not the source of T cs degradation but rather an increase of the compressive strain in the Nb 3Sn filaments possibly induced by longitudinal movement of the wires. Like all TF conductors this TF VNIINM conductor showed large transverse motions under Lorentz force loading, but Tcs actually increased, as in all short twist pitch CS conductors. We here propose that the high surface roughness of the VNIINM strand may be responsible for the suppression of the compressive strain enhancement (characteristic of long twist pitch conductors). Furthermore, it appears that increasing strand surface roughness could improve the performance of long twist pitch CICCs.« less

Metallographic autopsies of full-scale ITER prototype cable-in-conduit conductors after full cyclic testing in SULTAN: III. The importance of strand surface roughness in long twist pitch conductors

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

Sanabria, Charlie; Lee, Peter J.; Starch, William

As part of the ITER conductor qualification process, 3 m long Cable-in-Conduit Conductors (CICCs) were tested at the SULTAN facility under conditions simulating ITER operation so as to establish the current sharing temperature, T cs, as a function of multiple full Lorentz force loading cycles. After a comprehensive evaluation of both the Toroidal Field (TF) and the Central Solenoid (CS) conductors, it was found that T cs degradation was common in long twist pitch TF conductors while short twist pitch CS conductors showed some T cs increase. However, one kind of TF conductors containing superconducting strand fabricated by the Bochvarmore » Institute of Inorganic Materials (VNIINM) avoided T cs degradation despite having long twist pitch. In our earlier metallographic autopsies of long and short twist pitch CS conductors, we observed a substantially greater transverse strand movement under Lorentz force loading for long twist pitch conductors, while short twist pitch conductors had negligible transverse movement. With help from the literature, we concluded that the transverse movement was not the source of T cs degradation but rather an increase of the compressive strain in the Nb 3Sn filaments possibly induced by longitudinal movement of the wires. Like all TF conductors this TF VNIINM conductor showed large transverse motions under Lorentz force loading, but Tcs actually increased, as in all short twist pitch CS conductors. We here propose that the high surface roughness of the VNIINM strand may be responsible for the suppression of the compressive strain enhancement (characteristic of long twist pitch conductors). Furthermore, it appears that increasing strand surface roughness could improve the performance of long twist pitch CICCs.« less

The Carbon Monoxide Tape Recorder

NASA Technical Reports Server (NTRS)

Schoeberl, M. R.; Duncan, B. N.; Douglass, A. R.; Waters, J.; Livesey, N.; Read, W.; Filipiak, M.

2006-01-01

Using Aura MLS data we have identified the stratospheric tape recorder in carbon monoxide (CO). Unlike the water vapor tape recorder, which is controlled by upper troposphere processes, the CO tape recorder is linked to seasonal biomass burning. Since CO has a lifetime of only a few months, the CO tape recorder barely extends above 20 km. The tape head for CO appears to be close to 360K near the same location as the water vapor tape head [Read et al, 20041. Both tape heads are below the equatorial cold point tropopause but above the base of the tropical tropopause layer. The tape recorder signal becomes more distinct from 360K to 380K suggesting that convective detrainment of plays a decreasingly important role with altitude. The Global Modeling Initiative chemical transport model forced by the climatology of biomass burning reproduces the CO tape recorder.

Formation of qualified BaHfO3 doped Y0.5Gd0.5Ba2Cu3O7-δ film on CeO2 buffered IBAD-MgO tape by self-seeding pulsed laser deposition

NASA Astrophysics Data System (ADS)

Liu, Linfei; Wang, Wei; Yao, Yanjie; Wu, Xiang; Lu, Saidan; Li, Yijie

2018-05-01

Improvement in the in-filed transport properties of REBa2Cu3O7-δ (RE = rare earth elements, REBCO) coated conductor is needed to meet the performance requirements for various practical applications, which can be accomplished by introducing artificial pinning centers (APCs), such as second phase dopant. However, with increasing dopant level the critical current density Jc at 77 K in zero applied magnetic field decreases. In this paper, in order to improve Jc we propose a seed layer technique. 5 mol% BaHfO3 (BHO) doped Y0.5Gd0.5Ba2Cu3O7-δ (YGBCO) epilayer with an inserted seed layer was grown on CeO2 buffered ion beam assisted deposition MgO (IBAD-MgO) tape by pulsed laser deposition. The effect of the conditions employed to prepare the seed layer, including tape moving speed and chemical composition, on the quality of 5 mol% BHO doped YGBCO epilayer was systematically investigated by X-ray diffraction (XRD) measurements and scanning electron microscopy (SEM) observations. It was found that all the samples with seed layer have higher Jc (77 K, self-field) than the 5 mol% BHO doped YGBCO film without seed layer. The seed layer could inhibit deterioration of the Jc at 77 K and self-filed. Especially, the self-seed layer (5 mol% BHO doped YGBCO seed layer) was more effective in improving the crystal quality, surface morphology and superconducting performance. At 4.2 K, the 5 mol% BHO doped YGBCO film with 4 nm thick self-seed layer had a very high flux pinning force density Fp of 860 GN/m3 for B//c under a 9 T field, and more importantly, the peak of the Fp curve was not observed.

Effect of barrier perturbation on cutaneous penetration of salicylic acid in hairless rats: in vivo pharmacokinetics using microdialysis and non-invasive quantification of barrier function.

PubMed

Benfeldt, E; Serup, J

1999-09-01

The penetration of topically applied drugs is altered in diseased or barrier-damaged skin. We used microdialysis in the dermis to measure salicylic acid (SA) penetration in hairless rats following application to normal (unmodified) skin (n = 11) or skin with perturbed barrier function from (1) tape-stripping (n = 5), (2) sodium lauryl sulphate (SLS) 2% for 24 h (n = 3) or (3) delipidization by acetone (n = 4). Prior to the experiment, transepidermal water loss (TEWL) and erythema were measured. Two microdialysis probes were inserted into the dermis on the side of the trunk and 5% SA in ethanol was applied in a chamber overlying the probes. Microdialysis sampling was continued for 4 h, followed by measurements of probe depth by ultrasound scanning. SA was detectable in all samples and rapidly increasing up to 130 min. Microdialysates collected between 80 and 200 min showed mean SA concentrations of 3 microg/ml in unmodified and acetone-treated skin, whereas mean SA concentrations were 280 microg/ml in SLS-pretreated skin and 530 microg/ml in tape-stripped skin (P < 0.001). The penetration of SA correlated with barrier perturbation measured by TEWL (P < 0.001) and erythema (P < 0.001). A correlation between dermal probe depth and SA concentration was found in unmodified skin (P = 0.04). Microdialysis sampling in anatomical regions remote from the dosed site excluded the possibility that SA levels measured were due to systemic absorption. Microdialysis sampling of cutaneous penetration was highly reproducible. Impaired barrier function, caused by irritant dermatitis or tape stripping, resulted in an 80- to 170-fold increase in the drug level in the dermis. This dramatic increase in drug penetration could be relevant to humans, in particular to topical treatment of skin diseases and to occupational toxicology.

Spectral determinants for twist field correlators

NASA Astrophysics Data System (ADS)

Belitsky, A. V.

2018-04-01

Twist fields were introduced a few decades ago as a quantum counterpart to classical kink configurations and disorder variables in low dimensional field theories. In recent years they received a new incarnation within the framework of geometric entropy and strong coupling limit of four-dimensional scattering amplitudes. In this paper, we study their two-point correlation functions in a free massless scalar theory, namely, twist-twist and twist-antitwist correlators. In spite of the simplicity of the model in question, the properties of the latter are far from being trivial. The problem is reduced, within the formalism of the path integral, to the study of spectral determinants on surfaces with conical points, which are then computed exactly making use of the zeta function regularization. We also provide an insight into twist correlators for a massive complex scalar by means of the Lifshitz-Krein trace formula.

Strength of surgical wire fixation. A laboratory study.

PubMed

Guadagni, J R; Drummond, D S

1986-08-01

Because of the frequent use of stainless steel wire in spinal surgery and to augment fracture fixation, several methods of securing wire fixation were tested in the laboratory to determine the relative strength of fixation. Any method of fixation stronger than the yield strength of the wire is sufficient. Square knots, knot twists, symmetric twists, and the AO loop-tuck techniques afforded acceptable resistance against tension loads, but the wire wrap and AO loop technique were unacceptable. The double symmetric twist, which is frequently used for tension banding, was barely acceptable. The symmetric twist technique was the most practical because it is strong enough, efficient in maintaining tension applied during fixation, and least likely to cause damage to the wire. To optimize the fixation strength of the symmetrical twist, at least two twists are required at a reasonably tight pitch.

THE EFFECT OF A TWISTED MAGNETIC FIELD ON THE PERIOD RATIO P{sub 1}/P{sub 2} OF NONAXISYMMETRIC MAGNETOHYDRODYNAMIC WAVES

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

Karami, K.; Bahari, K., E-mail: KKarami@uok.ac.ir, E-mail: K.Bahari@razi.ac.ir

2012-10-01

We consider nonaxisymmetric magnetohydrodynamic (MHD) modes in a zero-beta cylindrical compressible thin magnetic flux tube modeled as a twisted core surrounded by a magnetically twisted annulus, with both embedded in a straight ambient external field. The dispersion relation is derived and solved analytically and numerically to obtain the frequencies of the nonaxisymmetric MHD waves. The main result is that the twisted magnetic annulus does affect the period ratio P{sub 1}/P{sub 2} of the kink modes. For the kink modes, the magnetic twist in the annulus region can achieve deviations from P{sub 1}/P{sub 2} = 2 of the same order ofmore » magnitude as in the observations. Furthermore, the effect of the internal twist on the fluting modes is investigated.« less

To investigate the relation between pore size and twist angle in enhanced thermoelectric efficient porous armchair graphene nanoribbons

NASA Astrophysics Data System (ADS)

Kaur, Sukhdeep; Randhawa, Deep Kamal Kaur; Bindra Narang, Sukhleen

2018-05-01

Based on Non-Equilibrium Green’s function method, we demonstrate that the twisted deformation is an efficient method to improve the figure of merit ZT of porous armchair graphene nanoribbons AGNRs. The peak value of ZT can be obtained for a certain tunable twist angle. Further analysis shows that the tunable twist angle exhibits an inverse relationship with the pore size laying forth the designers a choice for the larger twists to be replaced by smaller ones simply by increasing the size of the pore. Ballistic transport regime and semi-empirical method using Huckel basis set is used to obtain the electrical properties while the Tersoff potential is employed for the phononic system. These interesting findings indicate that the twisted porous AGNRs can be utilized as designing materials for potential thermoelectric applications.

Mesoporous Silica Nanoparticle Delivery of Chemically Modified siRNA Against TWIST1 Leads to Reduced Tumor Burden

PubMed Central

Finlay, James; Roberts, Cai M.; Dong, Juyao; Zink, Jeffrey I.; Tamanoi, Fuyuhiko; Glackin, Carlotta A.

2015-01-01

Growth and progression of solid tumors depends on the integration of multiple pro-growth and survival signals, including the induction of angiogenesis. TWIST1 is a transcription factor whose reactivation in tumors leads to epithelial to mesenchymal transition (EMT), including increased cancer cell stemness, survival, and invasiveness. Additionally, TWIST1 drives angiogenesis via activation of IL-8 and CCL2, independent of VEGF signaling. In this work, results suggest that chemically modified siRNA against TWIST1 reverses EMT both in vitro and in vivo. siRNA delivery with a polyethyleneimine-coated mesoporous silica nanoparticle (MSN) led to reduction of TWIST1 target genes and migratory potential in vitro. In mice bearing xenograft tumors, weekly intravenous injections of the siRNA-nanoparticle complexes resulted in decreased tumor burden together with a loss of CCL2 suggesting a possible anti-angiogenic response. Therapeutic use of TWIST1 siRNA delivered via MSNs has the potential to inhibit tumor growth and progression in many solid tumor types. Chemically modified siRNA against TWIST1 was complexed to cation-coated mesoporous silica nanoparticles and tested in vitro and in vivo. In cell culture experiments, siRNA reduced expression of TWIST1 and its target genes, and reduced cell migration. In mice, injections of the siRNA-nanoparticle complex led to reduced tumor weight. Data suggest that diminished tumor burden was the result of reduced CCL2 expression and angiogenesis following TWIST1 knockdown. PMID:26115637

Tape transport mechanism

DOEpatents

Groh, Edward F.; McDowell, William; Modjeski, Norbert S.; Keefe, Donald J.; Groer, Peter

1979-01-01

A device is provided for transporting, in a stepwise manner, tape between a feed reel and takeup reel. An indexer moves across the normal path of the tape displacing it while the tape on the takeup reel side of the indexer is braked. After displacement, the takeup reel takes up the displaced tape while the tape on the feed reel side of the indexer is braked, providing stepwise tape transport in precise intervals determined by the amount of displacement caused by the indexer.

Twisted surfaces with vanishing curvature in Galilean 3-space

NASA Astrophysics Data System (ADS)

Dede, Mustafa; Ekici, Cumali; Goemans, Wendy; Ünlütürk, Yasin

In this work, we define twisted surfaces in Galilean 3-space. In order to construct these surfaces, a planar curve is subjected to two simultaneous rotations, possibly with different rotation speeds. The existence of Euclidean rotations and isotropic rotations leads to three distinct types of twisted surfaces in Galilean 3-space. Then we classify twisted surfaces in Galilean 3-space with zero Gaussian curvature or zero mean curvature.

Twisting integrin receptors increases endothelin-1 gene expression in endothelial cells

NASA Technical Reports Server (NTRS)

Chen, J.; Fabry, B.; Schiffrin, E. L.; Wang, N.; Ingber, D. E. (Principal Investigator)

2001-01-01

A magnetic twisting stimulator was developed based on the previously published technique of magnetic twisting cytometry. Using ligand-coated ferromagnetic microbeads, this device can apply mechanical stresses with varying amplitudes, duration, frequencies, and waveforms to specific cell surface receptors. Biochemical and biological responses of the cells to the mechanical stimulation can be assayed. Twisting integrin receptors with RGD (Arg-Gly-Asp)-containing peptide-coated beads increased endothelin-1 (ET-1) gene expression by >100%. In contrast, twisting scavenger receptors with acetylated low-density lipoprotein-coated beads or twisting HLA antigen with anti-HLA antibody-coated beads did not lead to alterations in ET-1 gene expression. In situ hybridization showed that the increase in ET-1 mRNA was localized in the cells that were stressed with the RGD-coated beads. Blocking stretch-activated ion channels with gadolinium, chelating Ca2+ with EGTA, or inhibiting tyrosine phosphorylation with genistein abolished twist-induced ET-1 mRNA elevation. Abolishing cytoskeletal tension with an inhibitor of the myosin ATPase, with an inhibitor of myosin light chain kinase, or with an actin microfilament disrupter blocked twisted-induced increases in ET-1 expression. Our results are consistent with the hypothesis that the molecular structural linkage of integrin-cytoskeleton is an important pathway for stress-induced ET-1 gene expression.

Charge transport properties of poly(dA)-poly(dT) DNA in variation of backbone disorder and amplitude of base-pair twisting motion

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

Rahmi, Kinanti Aldilla, E-mail: kinanti.aldilla@ui.ac.id; Yudiarsah, Efta

By using tight binding Hamiltonian model, charge transport properties of poly(dA)-poly(dT) DNA in variation of backbone disorder and amplitude of base-pair twisting motion is studied. The DNA chain used is 32 base pairs long poly(dA)-poly(dT) molecule. The molecule is contacted to electrode at both ends. The influence of environment on charge transport in DNA is modeled as variation of backbone disorder. The twisting motion amplitude is taking into account by assuming that the twisting angle distributes following Gaussian distribution function with zero average and standard deviation proportional to square root of temperature and inversely proportional to the twisting motion frequency.more » The base-pair twisting motion influences both the onsite energy of the bases and electron hopping constant between bases. The charge transport properties are studied by calculating current using Landauer-Buttiker formula from transmission probabilities which is calculated by transfer matrix methods. The result shows that as the backbone disorder increases, the maximum current decreases. By decreasing the twisting motion frequency, the current increases rapidly at low voltage, but the current increases slower at higher voltage. The threshold voltage can increase or decrease with increasing backbone disorder and increasing twisting frequency.« less

Structural and electron diffraction scaling of twisted graphene bilayers

NASA Astrophysics Data System (ADS)

Zhang, Kuan; Tadmor, Ellad B.

2018-03-01

Multiscale simulations are used to study the structural relaxation in twisted graphene bilayers and the associated electron diffraction patterns. The initial twist forms an incommensurate moiré pattern that relaxes to a commensurate microstructure comprised of a repeating pattern of alternating low-energy AB and BA domains surrounding a high-energy AA domain. The simulations show that the relaxation mechanism involves a localized rotation and shrinking of the AA domains that scales in two regimes with the imposed twist. For small twisting angles, the localized rotation tends to a constant; for large twist, the rotation scales linearly with it. This behavior is tied to the inverse scaling of the moiré pattern size with twist angle and is explained theoretically using a linear elasticity model. The results are validated experimentally through a simulated electron diffraction analysis of the relaxed structures. A complex electron diffraction pattern involving the appearance of weak satellite peaks is predicted for the small twist regime. This new diffraction pattern is explained using an analytical model in which the relaxation kinematics are described as an exponentially-decaying (Gaussian) rotation field centered on the AA domains. Both the angle-dependent scaling and diffraction patterns are in quantitative agreement with experimental observations. A Matlab program for extracting the Gaussian model parameters accompanies this paper.

FGGE/ERBZ tape specification and shipping letter description

NASA Technical Reports Server (NTRS)

Han, D.; Lo, H.

1983-01-01

The FGGE/ERBZ tape contains 5 parameters which are extracted and reformatted from the Nimbus-7 ERB Zonal Means Tape. There are three types of files on a FGGE/ERBZ tape: a tape header file, and data files. Physical characteristics, gross format, and file specifications are given. A sample tape check/document printout (shipping letter) is included.

Tests of the standard (30 hz) NCER FM multiplex telemetry system, augmented by two timing channels and a compensation reference signal, used to record multiplexed seismic network data on magnetic tape

USGS Publications Warehouse

Eaton, Jerry P.

1976-01-01

The application of subtractive compensation to USGS seismic magnetic tape recording and playback systems was examined in a recent USGS Open-file report (1). It was found, for the standard (30 Hz) NCER multiplex system, that subtractive compensation utilizing a 4688 Hz reference signal multiplexed onto each data track was more effective than that utilizing a 3125 Hz reference signal recorded separately on a different track. Moreover, it was found that the portion of the spectrum between the uppermost data channel (3060 Hz + or - 125 Hz) and the compensation reference signal (4688 Hz) could be used to record an additional timing signal, with a center frequency of 3700 Hz and a broader playback bandwidth (ca 0 to 100 Hz) than that of the standard data channels. Accordingly, for the tests described in that report, the standard 8-datachannel multiplex system was augmented by one additional timing channel with a center frequency of 3700 Hz. The 3700 Hz discriminator used in those tests was not successfully set up to utilize subtractive compensation; so its output from a tape playback was quite noisy. Subsequently, further tests have been carried out on the application of subtractive compensation to a 4-channel broad-band multiplex system and to the standard multiplex system, both recorded on field tape recorders with relatively poor tape speed control (2), (3). In the course of these experiments, it was discovered that two separate timing channe1s, not just one, can be inserted between the uppermost data channel and the compensation reference signal, Furthermore, it was possible to adjust the discriminators used to playback these timing channels so that they profited significantly from subtractive compensation even though the playback bandwidth was 0 to 100 Hz (for short rise times of square wave timing signals). The advantages of recording two timing signals on each data track include: 1) one standard time signal to be used for critical timing, e.g. IRIG E, can be recorded with the data on each track, eliminating any problem that might arise from tape head misalignment if the timing base were recorded on a separate track from the data signals being timed, 2) other essential timing signals e.g. WWVB and IRIG C, can each be recorded on several tracks, to insure more reliable recording through redundancy, without displacing data from standard data channels, 3) the broader playback bandwidth of the special timing channels reproduces the sharp-edged timing codes with much less distortion than is obtained from the standard data channels. In order to implement subtractive compensation with the 4688 Hz multiplexed signal and to record timing signals on the proposed special timing channels, it was necessary to design and build a signal generator/multiplexer unit. The functions of this unit are: 1) generate a stable (x-tal controlled) compensation reference frequency (4688 Hz), 2) generate two timing channel subcarriers (3500 Hz and 3950 Hz) and provide for their modulation by appropriate timing signals, 3) separately, for each of th~14 tape tracks, adjust the relative levels of the timing and compensation subcarriers and multiplex them, at the appropriate level, with the incoming multiplexed data signals for introduction to the tape system direct record amplifiers. These units will be described in detail by Gray Jensen, who designed and built them, as well as being shown diagrammatically in this report. This report continues the work described in reference (1), and it should be read as a supplement to that report rather than as an independent effort. It introduces changes in the multiplex system and test circuits employed in the tests and then repeats the tests from the earlier report that are required to illustrate the characteristics of the modified system.

Twisted sigma-model solitons on the quantum projective line

NASA Astrophysics Data System (ADS)

Landi, Giovanni

2018-04-01

On the configuration space of projections in a noncommutative algebra, and for an automorphism of the algebra, we use a twisted Hochschild cocycle for an action functional and a twisted cyclic cocycle for a topological term. The latter is Hochschild-cohomologous to the former and positivity in twisted Hochschild cohomology results into a lower bound for the action functional. While the equations for the critical points are rather involved, the use of the positivity and the bound by the topological term lead to self-duality equations (thus yielding twisted noncommutative sigma-model solitons, or instantons). We present explicit nontrivial solutions on the quantum projective line.

Influence of TVT properties on outcomes of midurethral sling procedures: high-stiffness versus low-stiffness tape.

PubMed

Prien-Larsen, Jens Christian; Prien-Larsen, Thomas; Cieslak, Lars; Dessau, Ram B

2016-07-01

Although there is clear consensus on the use of monofilament polypropylene tapes for treating stress urinary incontinence (SUI), tapes differ in weight, stiffness, and elasticity. In this study, we compared outcomes of two tape types: high-stiffness Intramesh SOFT L.I.F.T versus low-stiffness Intramesh L.I.F.T. tape. Our null hypothesis was that in terms of performance, SOFT tape equaled L.I.F.T. tape. Six hundred and sixty women underwent prospective transvaginal tape (TVT) surgery for SUI: 210 had the SOFT tape placed and 450 the L.I.F.T. tape. Follow-ups were scheduled at 3 and 12 months. Objective cure at 3-months' follow-up was 87 % in the SOFT group vs 94 % in the L.I.F.T. group (p = 0.003) and at 12 months 86 vs 96 % (p = 0.0004), respectively. Subjective outcomes were equal. For SOFT tape, the objective failure rate at 3 months was especially pronounced in women older than 70 years: 31 vs 10 % (p = 0.008), and subjective failure was 24 vs 7 % (p = 0.01). At 12 months, objective failure for the SOFT tape was significantly higher in both age groups compared with L.I.F.T. [odds ratio (OR) 2.17]. Multivariate analysis showed that body mass index (BMI) ≥30 (OR 2.41), mixed incontinence (MUI) (OR 2.24), use of SOFT tape (OR 2.17), and age ≥ 70 years are significant independent risk factors for surgical failure. Outcomes with SOFT tape are significantly inferior than with L.I.F.T. tape, especially among elderly women. Therefore, the two variants of monofilament polypropylene tape are not interchangeable.

The Broselow and Handtevy Resuscitation Tapes: A Comparison of the Performance of Pediatric Weight Prediction.

PubMed

Lowe, Calvin G; Campwala, Rashida T; Ziv, Nurit; Wang, Vincent J

2016-08-01

To assess the performance of two pediatric length-based tapes (Broselow and Handtevy) in predicting actual weights of US children. In this descriptive study, weights and lengths of children (newborn through 13 years of age) were extracted from the 2009-2010 National Health and Nutrition Examination Survey (NHANES). Using the measured length ranges for each tape and the NHANES-extracted length data, every case from the study sample was coded into Broselow and Handtevy zones. Mean weights were calculated for each zone and compared to the predicted Broselow and Handtevy weights using measures of bias, precision, and accuracy. A sub-sample was examined that excluded cases with body mass index (BMI)≥95th percentile. Weights of children longer than each tape also were examined. A total of 3,018 cases from the NHANES database met criteria. Although both tapes underestimated children's weight, the Broselow tape outperformed the Handtevy tape across most length ranges in measures of bias, precision, and accuracy of predicted weights relative to actual weights. Accuracy was higher in the Broselow tape for shorter children and in the Handtevy tape for taller children. Among the sub-sample with cases of BMI≥95th percentile removed, performance of the Handtevy tape improved, yet the Broselow tape still performed better. When assessing the weights of children who were longer than either tape, the actual mean weights did not approximate adult weights; although, those exceeding the Handtevy tape were closer. For pediatric weight estimation, the Broselow tape performed better overall than the Handtevy tape and more closely approximated actual weight. Lowe CG , Campwala RT , Ziv N , Wang VJ . The Broselow and Handtevy resuscitation tapes: a comparison of the performance of pediatric weight prediction. Prehosp Disaster Med. 2016;31(4):364-375.

Effects of a paraspinal-lumbar tape application during 7 days on the perceived area of tape contact.

PubMed

Funk, Stefan; Finke, Roy; Zeh, Stefan; Siebert, Tobias; Puta, Christian

2017-05-01

The study aimed to investigate the changes of the perceived area of tape contact during a lumbar tape application that lasted 7 days. Single group, repeated measures study. University research laboratory. Twenty-three healthy collegiate students in sports science. Perceived area of tape contact was collected by preparing a drawing of their individual perceived tape outline into a printed body image. Measurements were obtained immediately after fixation of the tape (day 0), at day 3 and day 7 during application and 5 min after the release of the application (day 7). There was no significant change of the perceived area of tape contact after 3 days of tape application. A significant decrease in the perceived area of tape contact was detected 7 days after application (p < 0.05) and after detaching the tape (p < 0.01) compared to the first measurement. Our results indicate that the perception of the area of tape contact of healthy sport students is decreased at 7 days. This effect could not be observed at 3 days. These results provide relevant information for the use of elastic tapes concerning the duration of application in medical therapy. Copyright © 2016 Elsevier Ltd. All rights reserved.

Explicit formulae for Chern-Simons invariants of the twist-knot orbifolds and edge polynomials of twist knots

NASA Astrophysics Data System (ADS)

Ham, J.-Y.; Lee, J.

2016-09-01

We calculate the Chern-Simons invariants of twist-knot orbifolds using the Schläfli formula for the generalized Chern-Simons function on the family of twist knot cone-manifold structures. Following the general instruction of Hilden, Lozano, and Montesinos-Amilibia, we here present concrete formulae and calculations. We use the Pythagorean Theorem, which was used by Ham, Mednykh and Petrov, to relate the complex length of the longitude and the complex distance between the two axes fixed by two generators. As an application, we calculate the Chern-Simons invariants of cyclic coverings of the hyperbolic twist-knot orbifolds. We also derive some interesting results. The explicit formulae of the A-polynomials of twist knots are obtained from the complex distance polynomials. Hence the edge polynomials corresponding to the edges of the Newton polygons of the A-polynomials of twist knots can be obtained. In particular, the number of boundary components of every incompressible surface corresponding to slope -4n+2 turns out to be 2. Bibliography: 39 titles.

Scanning tunneling microscopy and spectroscopy of twisted trilayer graphene

NASA Astrophysics Data System (ADS)

Zuo, Wei-Jie; Qiao, Jia-Bin; Ma, Dong-Lin; Yin, Long-Jing; Sun, Gan; Zhang, Jun-Yang; Guan, Li-Yang; He, Lin

2018-01-01

Twist, as a simple and unique degree of freedom, could lead to enormous novel quantum phenomena in bilayer graphene. A small rotation angle introduces low-energy van Hove singularities (VHSs) approaching the Fermi level, which result in unusual correlated states in the bilayer graphene. It is reasonable to expect that the twist could also affect the electronic properties of few-layer graphene dramatically. However, such an issue has remained experimentally elusive. Here, by using scanning tunneling microscopy/spectroscopy (STM/STS), we systematically studied a twisted trilayer graphene (TTG) with two different small twist angles between adjacent layers. Two sets of VHSs, originating from the two twist angles, were observed in the TTG, indicating that the TTG could be simply regarded as a combination of two different twisted bilayers of graphene. By using high-resolution STS, we observed a split of the VHSs and directly imaged the spatial symmetry breaking of electronic states around the VHSs. These results suggest that electron-electron interactions play an important role in affecting the electronic properties of graphene systems with low-energy VHSs.

40 CFR 1066.225 - Roll runout and diameter verification procedure.

Code of Federal Regulations, 2013 CFR

2013-07-01

... section. (2) Measure roll diameter using a Pi Tape®. Orient the Pi Tape® to the marker line at the desired measurement location with the Pi Tape® hook pointed outward. Temporarily secure the Pi Tape® to the roll near the hook end with adhesive tape. Slowly turn the roll, wrapping the Pi Tape® around the roll surface...

40 CFR 1066.225 - Roll runout and diameter verification procedure.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) Measure roll diameter using a Pi Tape®. Orient the Pi Tape® to the marker line at the desired measurement location with the Pi Tape® hook pointed outward. Temporarily secure the Pi Tape® to the roll near the hook end with adhesive tape. Slowly turn the roll, wrapping the Pi Tape® around the roll surface. Ensure...

40 CFR 1066.225 - Roll runout and diameter verification procedure.

Code of Federal Regulations, 2012 CFR

2012-07-01

... section. (2) Measure roll diameter using a Pi Tape®. Orient the Pi Tape® to the marker line at the desired measurement location with the Pi Tape® hook pointed outward. Temporarily secure the Pi Tape® to the roll near the hook end with adhesive tape. Slowly turn the roll, wrapping the Pi Tape® around the roll surface...

FGGE/ERBM tape specification and shipping letter description

NASA Technical Reports Server (NTRS)

Han, D.; Lo, H.

1983-01-01

The Nimbus-7 FGGE/ERBM tape contains 27 ERB parameters which are extracted and reformatted from the Nimbus-7 ERB-MATRIX tape. There are four types of files on a FGGE/ERBM tape: a test file; tape-header file which describes the data set characteristics and the contents of the tape; a grid-descriptor file which contains the information of the ERB scanning channel target number and their associated latitude limits and longitude intervals; and one or more data files. A single end-of-file (EOF) tape mark is written after each file, and two EOF marks are written after the last data file on the tape.

The Effects of Rigid Scapular Taping on the Subacromial Space in Athletes With and Without Rotator Cuff Tendinopathy: A Randomized-Controlled Study.

PubMed

Leong, Hio Teng; Fu, Siu Ngor

2018-02-21

Reduction of the subacromial space (SAS) during arm elevation may contribute to rotator cuff tendinopathy. The effects of scapular taping on the SAS in athletes with and without RC tendinopathy is unknown. To investigate the immediate effects of scapular taping on the SAS in athletes with and without RC tendinopathy. Randomized-controlled with repeated measures. University laboratory. Forty-three male volleyball players (17 asymptomatic and 26 with RC tendinopathy, mean age = 22.9±3.5 years) participated in the study. Three scapular taping protocols - no taping (control), taping with tension (therapeutic taping) and taping without tension (sham taping). Ultrasound measurements of the SAS with the arm at 0° and 60° of shoulder abduction, and the change in the SAS between 0° and 60° of shoulder abduction (SAS 0°-60° ) were calculated. Athletes with RC tendinopathy demonstrated larger SAS with therapeutic taping at 60° of shoulder abduction (6.9±1.9 mm vs. 5.8±1.7 mm, mean difference = 1.1 mm, 95% CI = -1.80 - -0.39, p=0.002) when compared to the no taping condition. The tendinopathy group also showed less reduction in the SAS with therapeutic taping during SAS 0°-60° (2.0±1.4 mm vs. 2.8±1.4 mm, p=0.023) when compared to the no taping condition. When tape was applied to the scapula in asymptomatic athletes, our results showed a relatively small increase in the SAS with therapeutic taping during arm resting at 0° of abduction when compared to the no taping condition (8.7±0.9 mm vs. 8.3±0.8 mm, mean difference = 0.4 mm, 95% CI = -0.71 - -0.11, p=0.008). Athletes with RC tendinopathy demonstrated less reduction of the SAS with rigid scapular taping during early arm abduction. Such observation was not evidenced in asymptomatic athletes.

Experimental and theoretical study of the in- fiber twist sensor based on quasi-fan Solc structure filter.

PubMed

Sun, Chunran; Wang, Muguang; Jian, Shuisheng

2017-08-21

In this paper, a novel quasi-fan Solc structure filter based on elliptical-core spun fiber for twist sensing has been experimentally investigated and theoretically analyzed. The discrete model of spun fiber has been built to analyze the transmission characteristics of proposed sensor. Both experimental and simulated results indicate that the extinction ratio of the comb spectrum based on quasi-fan Solc birefringent fiber filter varies with twist angle and agrees well with each other. Based on the intensity modulation, the proposed twist sensor exhibits a high sensitivity of 0.02219 dB/(°/m). Moreover, thanks to the invariability of the fiber birefringence and the state of polarization of the input light, the proposed twist sensor has a very low temperature and strain sensitivity, which can avoid the cross-sensitivity problem existing in most twist sensors.

Two-pseudoscalar-meson decay of {chi}{sub cJ} with twist-3 corrections

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

Zhou Mingzhen; Zhou Haiqing; Department of Physics, Southeast University, Nanjing 211189

2009-11-01

The decays of {chi}{sub cJ}{yields}{pi}{sup +}{pi}{sup -}, K{sup +}K{sup -} (J=0,2) are discussed within the standard and modified hard-scattering approach when including the contributions from twist-3 distribution amplitudes and wave functions of the light pseudoscalar meson. A model for twist-2 and twist-3 distribution amplitudes and wave functions of the pion and kaon with BHL prescription are proposed as the solution to the end-point singularities. The results show that the contributions from twist-3 parts are actually not power suppressed comparing with the leading-twist contribution. After including the effects from the transverse momentum of light meson valence-quark state and Sudakov factors, themore » decay widths of the {chi}{sub cJ} into pions or kaons are comparable with the their experimental data.« less

Raman spectroscopy measurement of bilayer graphene's twist angle to boron nitride

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

Cheng, Bin; Wang, Peng; Pan, Cheng

2015-07-20

When graphene is placed on hexagonal boron nitride with a twist angle, new properties develop due to the resulting moiré superlattice. Here, we report a method using Raman spectroscopy to make rapid, non-destructive measurements of the twist angle between bilayer graphene and hexagonal boron nitride. The lattice orientation is determined by using flakes with both bilayer and monolayer regions, and using the known Raman signature for the monolayer to measure the twist angle of the entire flake. The widths of the second order Raman peaks are found to vary linearly in the superlattice period and are used to determine themore » twist angle. The results are confirmed by using transport measurements to infer the superlattice period by the charge density required to reach the secondary resistance peaks. Small twist angles are also found to produce a significant modification of the first order Raman G band peak.« less

Landau damping of Langmuir twisted waves with kappa distributed electrons

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

Arshad, Kashif, E-mail: kashif.arshad.butt@gmail.com; Aman-ur-Rehman; Mahmood, Shahzad

2015-11-15

The kinetic theory of Landau damping of Langmuir twisted modes is investigated in the presence of orbital angular momentum of the helical (twisted) electric field in plasmas with kappa distributed electrons. The perturbed distribution function and helical electric field are considered to be decomposed by Laguerre-Gaussian mode function defined in cylindrical geometry. The Vlasov-Poisson equation is obtained and solved analytically to obtain the weak damping rates of the Langmuir twisted waves in a nonthermal plasma. The strong damping effects of the Langmuir twisted waves at wavelengths approaching Debye length are also obtained by using an exact numerical method and aremore » illustrated graphically. The damping rates of the planar Langmuir waves are found to be larger than the twisted Langmuir waves in plasmas which shows opposite behavior as depicted in Fig. 3 by J. T. Mendoça [Phys. Plasmas 19, 112113 (2012)].« less

Acoustic Aspects of Active-Twist Rotor Control

NASA Technical Reports Server (NTRS)

Booth, Earl R., Jr.; Wilbur, Matthew L.

2002-01-01

The use of an Active Twist Rotor system to provide both vibration reduction and performance enhancement has been explored in recent analytical and experimental studies. Effects of active-twist control on rotor noise, however, had not been determined. During a recent wind tunnel test of an active-twist rotor system, a set of acoustic measurements were obtained to assess the effects of active-twist control on noise produced by the rotor, especially blade-vortex interaction (BVI) noise. It was found that for rotor operating conditions where BVI noise is dominant, active-twist control provided a reduction in BVI noise level. This BVI noise reduction was almost, but not quite, as large as that obtained in a similar test using HHC. However, vibration levels were usually adversely affected at operating conditions favoring minimum BVI noise. Conversely, operating conditions favoring minimum vibration levels affected BVI noise levels, but not always adversely.

Spectroscopic and Ab Initio Determination of the Ring-Twisting Potential Energy Function for 1,3-Cyclohexadiene

NASA Astrophysics Data System (ADS)

Autrey, Daniel; Choo, Jaebum; Laane, Jaan

2000-10-01

The ring-twisting vibration of 1,3-cyclohexadiene has been studied using Raman and infrared spectroscopy of the molecule in the vapor phase. The Raman spectrum shows five ring-twisting transitions in the 150 - 200 cm-1 region. The far-infrared spectrum shows only two transitions for this vibration, which is infrared forbidden in the C_2v (planar) approximation. Three ring-twisting combination bands were also observed off a fundamental vibration at 926.1 cm-1. A coordinate dependent kinetic energy expansion for the ring-twisting motion was calculated, and this was used to determine the ring-twisting potential function. Ab initio calculations were performed using Moller-Plesset perturbation theory (MP2) using different basis sets. The barrier to planarity of 1150 cm-1 was determined from the spectroscopic data. The various ab initio calculations gave barriers to planarity in the 1197 - 1593 cm-1 range.

Hygroscopic properties of magnetic recording tape

NASA Technical Reports Server (NTRS)

Cuddihy, E. F.

1976-01-01

Relative humidity has been recognized as an important environmental factor in many head-tape interface phenomena such as headwear, friction, staining, and tape shed. Accordingly, the relative humidity is usually specified in many applications of tape use, especially when tape recorders are enclosed in hermetically sealed cases. Normally, the relative humidity is believed regulated by humidification of the fill gas to the specification relative humidity. This study demonstrates that the internal relative humidity in a sealed case is completely controlled by the time-dpendence of the hygroscopic properties of the pack of magnetic recording tape. Differences are found in the hygroscopic properties of the same brand of tape, which apparently result from aging, and which may have an effect on the long-term humidity-regulating behavior in a sealed case, and on the occurrence of head-tape interface phenomena from the long-term use of the tape. Results are presented on the basic hygroscopic properties of magnetic tape, its humidity-regulating behavior in a sealed case, and a theoretical commentary on the relative humidity dependence of head-wear by tape, is included.

Development of an imaging system for in vivo real-time monitoring of neuronal activity in deep brain of free-moving rats.

PubMed

Iijima, Norio; Miyamoto, Shinji; Matsumoto, Keisuke; Takumi, Ken; Ueta, Yoichi; Ozawa, Hitoshi

2017-09-01

We have newly developed a system that allows monitoring of the intensity of fluorescent signals from deep brains of rats transgenically modified to express enhanced green fluorescent protein (eGFP) via an optical fiber. One terminal of the optical fiber was connected to a blue semiconductor laser oscillator/green fluorescence detector. The other terminal was inserted into the vicinity of the eGFP-expressing neurons. Since the optical fiber was vulnerable to twisting stresses caused by animal movement, we also developed a cage in which the floor automatically turns, in response to the turning of the rat's head. This relieved the twisting stress on the optical fiber. The system then enabled real-time monitoring of fluorescence in awake and unrestrained rats over many hours. Using this system, we could continuously monitor eGFP-expression in arginine vasopressin-eGFP transgenic rats. Moreover, we observed an increase of eGFP-expression in the paraventricular nucleus under salt-loading conditions. We then performed in vivo imaging of eGFP-expressing GnRH neurons in the hypothalamus, via a bundle consisting of 3000 thin optical fibers. With the combination of the optical fiber bundle connection to the fluorescence microscope, and the special cage system, we were able to capture and retain images of eGFP-expressing neurons from free-moving rats. We believe that our newly developed method for monitoring and imaging eGFP-expression in deep brain neurons will be useful for analysis of neuronal functions in awake and unrestrained animals for long durations.

High-resolution Observations of Flares in an Arch Filament System

NASA Astrophysics Data System (ADS)

Su, Yingna; Liu, Rui; Li, Shangwei; Cao, Wenda; Ahn, Kwangsu; Ji, Haisheng

2018-03-01

We study five sequential solar flares (SOL2015-08-07) occurring in Active Region 12396 observed with the Goode Solar Telescope (GST) at the Big Bear Solar Observatory, complemented by Interface Region Imaging Spectrograph and SDO observations. The main flaring region is an arch filament system (AFS) consisting of multiple bundles of dark filament threads enclosed by semicircular flare ribbons. We study the magnetic configuration and evolution of the active region by constructing coronal magnetic field models based on SDO/HMI magnetograms using two independent methods, i.e., the nonlinear force-free field (NLFFF) extrapolation and the flux rope insertion method. The models consist of multiple flux ropes with mixed signs of helicity, i.e., positive (negative) in the northern (southern) region, which is consistent with the GST observations of multiple filament bundles. The footprints of quasi-separatrix layers (QSLs) derived from the extrapolated NLFFF compare favorably with the observed flare ribbons. An interesting double-ribbon fine structure located at the east border of the AFS is consistent with the fine structure of the QSL’s footprint. Moreover, magnetic field lines traced along the semicircular footprint of a dome-like QSL surrounding the AFS are connected to the regions of significant helicity and Poynting flux injection. The maps of magnetic twist show that positive twist became dominant as time progressed, which is consistent with the injection of positive helicity before the flares. We hence conclude that these circular shaped flares are caused by 3D magnetic reconnection at the QSLs associated with the AFS possessing mixed signs of helicity.

Geometric Constraints and the Anatomical Interpretation of Twisted Plant Organ Phenotypes

PubMed Central

Weizbauer, Renate; Peters, Winfried S.; Schulz, Burkhard

2011-01-01

The study of plant mutants with twisting growth in axial organs, which normally grow straight in the wild-type, is expected to improve our understanding of the interplay among microtubules, cellulose biosynthesis, cell wall structure, and organ biomechanics that control organ growth and morphogenesis. However, geometric constraints based on symplastic growth and the consequences of these geometric constraints concerning interpretations of twisted-organ phenotypes are currently underestimated. Symplastic growth, a fundamental concept in plant developmental biology, is characterized by coordinated growth of adjacent cells based on their connectivity through cell walls. This growth behavior implies that in twisting axial organs, all cell files rotate in phase around the organ axis, as has been illustrated for the Arabidopsis spr1 and twd1 mutants in this work. Evaluating the geometry of such organs, we demonstrate that a radial gradient in cell elongation and changes in cellular growth anisotropy must occur in twisting organs out of geometric necessity alone. In-phase rotation of the different cell layers results in a decrease of length and angle toward organ axis from the outer cell layers inward. Additionally, the circumference of each cell layer increases in twisting organs, which requires compensation through radial expansion or an adjustment of cell number. Therefore, differential cell elongation and growth anisotropy cannot serve as arguments for or against specific hypotheses regarding the molecular cause of twisting growth. We suggest instead, that based on mathematical modeling, geometric constraints in twisting organs are indispensable for the explanation of the causal connection of molecular and biomechanical processes in twisting as well as normal organs. PMID:22645544

LGSOWG CCT format CCB document: The standard CCT family of tape formats

NASA Technical Reports Server (NTRS)

1979-01-01

The tape format standardization approach recommended by the committee on CCT standardization is described and defined. All rules and conventions required to employ the superstructure approach to the CCT family of tape formats are presented for users of remote sensing data and producer of user tapes and the superstructure records are specified. The standard for future tape format design is presented as a guide to designing data records of a particular tape format. An example is provided showing how to incorporate the superstructure into an already established tape format.

Enhanced epithelial to mesenchymal transition (EMT) and upregulated MYC in ectopic lesions contribute independently to endometriosis.

PubMed

Proestling, Katharina; Birner, Peter; Gamperl, Susanne; Nirtl, Nadine; Marton, Erika; Yerlikaya, Gülen; Wenzl, Rene; Streubel, Berthold; Husslein, Heinrich

2015-07-22

Epithelial to mesenchymal transition (EMT) is a process in which epithelial cells lose polarity and cell-to-cell contacts and acquire the migratory and invasive abilities of mesenchymal cells. These abilities are thought to be prerequisites for the establishment of endometriotic lesions. A hallmark of EMT is the functional loss of E-cadherin (CDH1) expression in epithelial cells. TWIST1, a transcription factor that represses E-cadherin transcription, is among the EMT inducers. SNAIL, a zinc-finger transcription factor, and its close relative SLUG have similar properties to TWIST1 and are thus also EMT inducers. MYC, which is upregulated by estrogens in the uterus by an estrogen response cis-acting element (ERE) in its promoter, is associated with proliferation in endometriosis. The role of EMT and proliferation in the pathogenesis of endometriosis was evaluated by analyzing TWIST1, CDH1 and MYC expression. CDH1, TWIST1, SNAIL and SLUG mRNA expression was analyzed by qRT-PCR from 47 controls and 74 patients with endometriosis. Approximately 42 ectopic and 62 eutopic endometrial tissues, of which 30 were matched samples, were collected during the same surgical procedure. We evaluated TWIST1 and MYC protein expression by immunohistochemistry (IHC) in the epithelial and stromal tissue of 69 eutopic and 90 ectopic endometrium samples, of which 49 matched samples were analyzed from the same patient. Concordant expression of TWIST1/SNAIL/SLUG and CDH1 but also of TWIST1 and MYC was analyzed. We found that TWIST1, SNAIL and SLUG are overexpressed (p < 0.001, p = 0.016 and p < 0.001) in endometriosis, while CDH1 expression was concordantly reduced in these samples (p < 0.001). Similar to TWIST1, the epithelial expression of MYC was also significantly enhanced in ectopic endometrium compared to eutopic tissues (p = 0.008). We found exclusive expression of either TWIST1 or MYC in the same samples (p = 0.003). Epithelial TWIST1 is overexpressed in endometriosis and may contribute to the formation of endometriotic lesions by inducing epithelial to mesenchymal transition, as CDH1 was reduced in ectopic lesions. We found exclusive expression of either TWIST1 or MYC in the same samples, indicating that EMT and proliferation contribute independently of each other to the formation of endometriotic lesions.

Patellar taping, patellofemoral pain syndrome, lower extremity kinematics, and dynamic postural control.

PubMed

Aminaka, Naoko; Gribble, Phillip A

2008-01-01

Patellar taping has been a part of intervention for treatment of patellofemoral pain syndrome (PFPS). However, research on the efficacy of patellar taping on lower extremity kinematics and dynamic postural control is limited. To evaluate the effects of patellar taping on sagittal-plane hip and knee kinematics, reach distance, and perceived pain level during the Star Excursion Balance Test (SEBT) in individuals with and without PFPS. Repeated-measures design with 2 within-subjects factors and 1 between-subjects factor. The University of Toledo Athletic Training Research Laboratory. Twenty participants with PFPS and 20 healthy participants between the ages of 18 and 29 years. The participants performed 3 reaches of the SEBT in the anterior direction under tape and no-tape conditions on both legs. The participants' hip and knee sagittal-plane kinematics were measured using the electromagnetic tracking system. Reach distance was recorded by hand and was normalized by dividing the distance by the participants' leg length (%MAXD). After each taping condition on each leg, the participants rated the perceived pain level using the 10-cm visual analog scale. The participants with PFPS had a reduction in pain level with patellar tape application compared with the no-tape condition (P = .005). Additionally, participants with PFPS demonstrated increased %MAXD under the tape condition compared with the no-tape condition, whereas the healthy participants demonstrated decreased %MAXD with tape versus no tape (P = .028). No statistically significant differences were noted in hip flexion and knee flexion angles. Although patellar taping seemed to reduce pain and improve SEBT performance of participants with PFPS, the exact mechanisms of these phenomena cannot be explained in this study. Further research is warranted to investigate the effect of patellar taping on neuromuscular control during dynamic postural control.

Description of the HiMAT Tailored composite structure and laboratory measured vehicle shape under load

NASA Technical Reports Server (NTRS)

Monaghan, R. C.

1981-01-01

The aeroelastically tailored outer wing and canard of the highly maneuverable aircraft technology (HiMAT) vehicle are closely examined and a general description of the overall structure of the vehicle is provided. Test data in the form of laboratory measured twist under load and predicted twist from the HiMAT NASTRAN structural design program are compared. The results of this comparison indicate that the measured twist is generally less than the NASTRAN predicted twist. These discrepancies in twist predictions are attributed, at least in part, to the inability of current analytical composite materials programs to provide sufficiently accurate properties of matrix dominated laminates for input into structural programs such as NASTRAN.

Demonstration of an elastically coupled twist control concept for tilt rotor blade application

NASA Technical Reports Server (NTRS)

Lake, R. C.; Nixon, M. W.; Wilbur, M. L.; Singleton, J. D.; Mirick, P. H.

1994-01-01

The purpose of this Note is to present results from an analytic/experimental study that investigated the potential for passively changing blade twist through the use of extension-twist coupling. A set of composite model rotor blades was manufactured from existing blade molds for a low-twist metal helicopter rotor blade, with a view toward establishing a preliminary proof concept for extension-twist-coupled rotor blades. Data were obtained in hover for both a ballasted and unballasted blade configuration in sea-level atmospheric conditions. Test data were compared with results obtained from a geometrically nonlinear analysis of a detailed finite element model of the rotor blade developed in MSC/NASTRAN.

A photometric determination of twists in early-type galaxies. II

NASA Technical Reports Server (NTRS)

Williams, T. B.; Schwarzschild, M.

1979-01-01

In continuation of previous work, detailed photometric data have been obtained for two elliptical galaxies by using the Mount Lemmon 1.5-m telescope and a large SEC television camera. As before, the aim of this photometry is to gain additional information on the occurrence of twists in such galaxies; i.e., on the change of the position angle of the major axes of the isophotes from the center outward. No significant twist was found in NGC 1052. However, NGC 584 was found to have a securely observed twist of about 10 deg within 10 kpc from its center. These data strengthen previous indications that many ellipticals contain twists in their inner, bright portions.

Enhancing contrast of fingerprints on plastic tape.

PubMed

Steele, Charles A; Ball, Mikki S

2003-11-01

Many of the currently available fingerprinting methods have limited ability to visualize fingerprints on plastic tape without expensive equipment or significant handling of the sample. This is especially true for visualizing fingerprints on black electrical tape. This study sought a hands-off method to produce easy visualization of fingerprints on different types of plastic tape, including black electrical tape, without the need for expensive equipment. The methods selected were to sublime disperse dyes into the tape, both with and without the fuming of cyanoacrylate, everywhere except for where the fingerprint was applied. The resulting color contrasts provided enough differentiation to visualize fingerprints on plastic tape under ambient light. Sequential fuming with cyanoacrylate followed by disperse dyes provided the best visualizations on all tapes, and cyanoacrylate followed by disperse yellow 211 clearly visualized fingerprints on black electrical tape.

User's guide and tape specification for ERB 7 DELMAT

NASA Technical Reports Server (NTRS)

Ardanuy, P.; Penn, L.

1985-01-01

Guidance is provided to the DELMAT user in the areas of purpose, use and limitations of DELMAT tapes and software. The DELMAT tape specifications is also provided. The ERB-7, ERB MAT and tape characteristics applicable to the DELMAT tapes are also summarized.

Lifshits Tails for Randomly Twisted Quantum Waveguides

NASA Astrophysics Data System (ADS)

Kirsch, Werner; Krejčiřík, David; Raikov, Georgi

2018-03-01

We consider the Dirichlet Laplacian H_γ on a 3D twisted waveguide with random Anderson-type twisting γ . We introduce the integrated density of states N_γ for the operator H_γ , and investigate the Lifshits tails of N_γ , i.e. the asymptotic behavior of N_γ (E) as E \\downarrow \\inf supp dN_γ . In particular, we study the dependence of the Lifshits exponent on the decay rate of the single-site twisting at infinity.

Twisted Vanes Would Enhance Fuel/Air Mixing In Turbines

NASA Technical Reports Server (NTRS)

Nguyen, H. Lee; Micklow, Gerald J.; Dogra, Anju S.

1994-01-01

Computations of flow show performance of high-shear airblast fuel injector in gas-turbine engine enhanced by use of appropriately proportioned twisted (instead of flat) dome swirl vanes. Resultant more nearly uniform fuel/air mixture burns more efficiently, emitting smaller amounts of nitrogen oxides. Twisted-vane high-shear airblast injectors also incorporated into paint sprayers, providing advantages of low pressure drop characteristic of airblast injectors in general and finer atomization of advanced twisted-blade design.

Kinesio taping or sham taping in knee osteoarthritis? A randomized, double-blind, sham-controlled trial.

PubMed

Kocyigit, Figen; Turkmen, Mehmet Besir; Acar, Merve; Guldane, Nezahat; Kose, Tugce; Kuyucu, Ersin; Erdil, Mehmet

2015-11-01

To compare effects of kinesio taping with sham taping at the end of 3 consecutive taping periods in knee osteoarthritis. 41 patients diagnosed with knee osteoarthritis according to American College of Rheumatology were randomized to receive either KT or sham taping. Baseline evaluations included a visual analog scale (VAS) for activity and nocturnal pain, Lequesne index for functional assessment and Nottingham Health Profile (NHP) for the quality of life. Taping was applied every four days, three times, and all of the assessments were repeated at the end of the treatment period. In both groups VAS for activity pain, VAS for nocturnal pain, Lequesne index score, NHP score decreased significantly. NHP energy scores were different significantly between the groups in favor of sham taping at the end of the 12-day period. Our findings indicate inconclusive evidence of a beneficial effect of kinesio taping over sham taping in knee osteoarthritis. Copyright © 2015 Elsevier Ltd. All rights reserved.

Specification for wide channel bandwidth one-inch video tape

NASA Technical Reports Server (NTRS)

Perry, Jimmy L.

1988-01-01

Standards and controls are established for the procurement of wide channel bandwidth one inch video magnetic recording tapes for Very Long Base Interferometer (VLBI) system applications. The Magnetic Tape Certification Facility (MTCF) currently maintains three specifications for the Quality Products List (QPL) and acceptance testing of magnetic tapes. NASA-TM-79724 is used for the QPL and acceptance testing of new analog tapes; NASA-TM-80599 is used for QPL and acceptance testing of new digital tapes; and NASA-TM-100702 is used for the QPL and acceptance testing of new IBM/IBM compatible 3480 magnetic tape cartridges. This specification will be used for the QPL and acceptance testing of new wide channel bandwidth one inch video magnetic recording tapes. The one inch video tapes used by the Jet Propulsion Lab., the Deep Space Network and the Haystack Observatory will be covered by this specification. These NASA stations will use the video tapes for their VLBI system applications. The VLBI system is used for the tracking of quasars and the support of interplanetary exploration.

Thymoquinone inhibits cancer metastasis by downregulating TWIST1 expression to reduce epithelial to mesenchymal transition.

PubMed

Khan, Md Asaduzzaman; Tania, Mousumi; Wei, Chunli; Mei, Zhiqiang; Fu, Shelly; Cheng, Jingliang; Xu, Jianming; Fu, Junjiang

2015-08-14

Proteins that promote epithelial to mesenchymal transition (EMT) are associated with cancer metastasis. Inhibition of EMT regulators may be a promising approach in cancer therapy. In this study, Thymoquinone (TQ) was used to treat cancer cell lines to investigate its effects on EMT-regulatory proteins and cancer metastasis. We show that TQ inhibited cancer cell growth, migration and invasion in a dose-dependent manner. At the molecular level, TQ treatment decreased the transcriptional activity of the TWIST1 promoter and the mRNA expression of TWIST1, an EMT-promoting transcription factor. Accordingly, TQ treatment also decreased the expression of TWIST1-upregulated genes such as N-Cadherin and increased the expression of TWIST1-repressed genes such as E-Cadherin, resulting in a reduction of cell migration and invasion. TQ treatment also inhibited the growth and metastasis of cancer cell-derived xenograft tumors in mice but partially attenuated the migration and invasion in TWIST1-overexpressed cell lines. Furthermore, we found that TQ treatment enhanced the promoter DNA methylation of the TWIST1 gene in BT 549 cells. Together, these results demonstrate that TQ treatment inhibits TWIST1 promoter activity and decreases its expression, leading to the inhibition of cancer cell migration, invasion and metastasis. These findings suggest TQ as a potential small molecular inhibitor of cancer growth and metastasis.

Thymoquinone inhibits cancer metastasis by downregulating TWIST1 expression to reduce epithelial to mesenchymal transition

PubMed Central

Khan, Md. Asaduzzaman; Tania, Mousumi; Wei, Chunli; Mei, Zhiqiang; Fu, Shelly; Cheng, Jingliang; Xu, Jianming; Fu, Junjiang

2015-01-01

Proteins that promote epithelial to mesenchymal transition (EMT) are associated with cancer metastasis. Inhibition of EMT regulators may be a promising approach in cancer therapy. In this study, Thymoquinone (TQ) was used to treat cancer cell lines to investigate its effects on EMT-regulatory proteins and cancer metastasis. We show that TQ inhibited cancer cell growth, migration and invasion in a dose-dependent manner. At the molecular level, TQ treatment decreased the transcriptional activity of the TWIST1 promoter and the mRNA expression of TWIST1, an EMT-promoting transcription factor. Accordingly, TQ treatment also decreased the expression of TWIST1-upregulated genes such as N-Cadherin and increased the expression of TWIST1-repressed genes such as E-Cadherin, resulting in a reduction of cell migration and invasion. TQ treatment also inhibited the growth and metastasis of cancer cell-derived xenograft tumors in mice but partially attenuated the migration and invasion in TWIST1-overexpressed cell lines. Furthermore, we found that TQ treatment enhanced the promoter DNA methylation of the TWIST1 gene in BT 549 cells. Together, these results demonstrate that TQ treatment inhibits TWIST1 promoter activity and decreases its expression, leading to the inhibition of cancer cell migration, invasion and metastasis. These findings suggest TQ as a potential small molecular inhibitor of cancer growth and metastasis. PMID:26023736

Projection Moire Interferometry for Rotorcraft Applications: Deformation Measurements of Active Twist Rotor Blades

NASA Technical Reports Server (NTRS)

Fleming, Gary A.; Soto, Hector L.; South, Bruce W.

2002-01-01

Projection Moire Interferometry (PMI) has been used during wind tunnel tests to obtain azimuthally dependent blade bending and twist measurements for a 4-bladed Active Twist Rotor (ATR) system in simulated forward flight. The ATR concept offers a means to reduce rotor vibratory loads and noise by using piezoelectric active fiber composite actuators embedded in the blade structure to twist each blade as they rotate throughout the rotor azimuth. The twist imparted on the blades for blade control causes significant changes in blade loading, resulting in complex blade deformation consisting of coupled bending and twist. Measurement of this blade deformation is critical in understanding the overall behavior of the ATR system and the physical mechanisms causing the reduction in rotor loads and noise. PMI is a non-contacting, video-based optical measurement technique capable of obtaining spatially continuous structural deformation measurements over the entire object surface within the PMI system field-of-view. When applied to rotorcraft testing, PMI can be used to measure the azimuth-dependent blade bending and twist along the full span of the rotor blade. This paper presents the PMI technique as applied to rotorcraft testing, and provides results obtained during the ATR tests demonstrating the PMI system performance. PMI measurements acquired at select blade actuation conditions generating minimum and maximum rotor loads are provided to explore the interrelationship between rotor loads, blade bending, and twist.

Recurrent Mutations in the Basic Domain of TWIST2 Cause Ablepharon Macrostomia and Barber-Say Syndromes.

PubMed

Marchegiani, Shannon; Davis, Taylor; Tessadori, Federico; van Haaften, Gijs; Brancati, Francesco; Hoischen, Alexander; Huang, Haigen; Valkanas, Elise; Pusey, Barbara; Schanze, Denny; Venselaar, Hanka; Vulto-van Silfhout, Anneke T; Wolfe, Lynne A; Tifft, Cynthia J; Zerfas, Patricia M; Zambruno, Giovanna; Kariminejad, Ariana; Sabbagh-Kermani, Farahnaz; Lee, Janice; Tsokos, Maria G; Lee, Chyi-Chia R; Ferraz, Victor; da Silva, Eduarda Morgana; Stevens, Cathy A; Roche, Nathalie; Bartsch, Oliver; Farndon, Peter; Bermejo-Sanchez, Eva; Brooks, Brian P; Maduro, Valerie; Dallapiccola, Bruno; Ramos, Feliciano J; Chung, Hon-Yin Brian; Le Caignec, Cédric; Martins, Fabiana; Jacyk, Witold K; Mazzanti, Laura; Brunner, Han G; Bakkers, Jeroen; Lin, Shuo; Malicdan, May Christine V; Boerkoel, Cornelius F; Gahl, William A; de Vries, Bert B A; van Haelst, Mieke M; Zenker, Martin; Markello, Thomas C

2015-07-02

Ablepharon macrostomia syndrome (AMS) and Barber-Say syndrome (BSS) are rare congenital ectodermal dysplasias characterized by similar clinical features. To establish the genetic basis of AMS and BSS, we performed extensive clinical phenotyping, whole exome and candidate gene sequencing, and functional validations. We identified a recurrent de novo mutation in TWIST2 in seven independent AMS-affected families, as well as another recurrent de novo mutation affecting the same amino acid in ten independent BSS-affected families. Moreover, a genotype-phenotype correlation was observed, because the two syndromes differed based solely upon the nature of the substituting amino acid: a lysine at TWIST2 residue 75 resulted in AMS, whereas a glutamine or alanine yielded BSS. TWIST2 encodes a basic helix-loop-helix transcription factor that regulates the development of mesenchymal tissues. All identified mutations fell in the basic domain of TWIST2 and altered the DNA-binding pattern of Flag-TWIST2 in HeLa cells. Comparison of wild-type and mutant TWIST2 expressed in zebrafish identified abnormal developmental phenotypes and widespread transcriptome changes. Our results suggest that autosomal-dominant TWIST2 mutations cause AMS or BSS by inducing protean effects on the transcription factor's DNA binding. Copyright © 2015 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

Calculating massive 3-loop graphs for operator matrix elements by the method of hyperlogarithms

NASA Astrophysics Data System (ADS)

Ablinger, Jakob; Blümlein, Johannes; Raab, Clemens; Schneider, Carsten; Wißbrock, Fabian

2014-08-01

We calculate convergent 3-loop Feynman diagrams containing a single massive loop equipped with twist τ=2 local operator insertions corresponding to spin N. They contribute to the massive operator matrix elements in QCD describing the massive Wilson coefficients for deep-inelastic scattering at large virtualities. Diagrams of this kind can be computed using an extended version of the method of hyperlogarithms, originally being designed for massless Feynman diagrams without operators. The method is applied to Benz- and V-type graphs, belonging to the genuine 3-loop topologies. In case of the V-type graphs with five massive propagators, new types of nested sums and iterated integrals emerge. The sums are given in terms of finite binomially and inverse binomially weighted generalized cyclotomic sums, while the 1-dimensionally iterated integrals are based on a set of ∼30 square-root valued letters. We also derive the asymptotic representations of the nested sums and present the solution for N∈C. Integrals with a power-like divergence in N-space ∝aN,a∈R,a>1, for large values of N emerge. They still possess a representation in x-space, which is given in terms of root-valued iterated integrals in the present case. The method of hyperlogarithms is also used to calculate higher moments for crossed box graphs with different operator insertions.

Surface microstructure of dental implants before and after insertion: an in vitro study by means of scanning probe microscopy.

PubMed

Salerno, Marco; Itri, Angelo; Frezzato, Marco; Rebaudi, Alberto

2015-06-01

The surface microstructure of dental implants affects osseointegration, which makes their accurate topographic characterization important. We defined a procedure for evaluation of implant topography before (pre-) and after (post-) in vitro implantation test in bovine bone. The apical morphology of ten implants was analyzed in pre- and post-conditions using atomic force microscopy or 3D profilometry. We extracted four topographical parameters (two amplitude, 1 spatial, and 1 hybrid) and assessed the differences by analysis of variance. The implant with coating (Spline Twist MP-1 HA) was damaged. The two implants with highest pre-amplitude parameters (Pitt Easy VTPS, TLR3815) maintained their character on testing. Pitt Easy PURETEX and OT-F1 were the only nondamaged implants whose amplitude parameters increased. The surface area underwent minor changes even when the texture changed (Tri-Vent, Pitt Easy PURETEX, Exp #1). The implants that ranked the lowest in all parameters before implantation were DT4013TI, Tri-Vent, OT-F1, and Exp #2. On testing, DT4013TI showed the highest decrease in values, whereas Tri-Vent showed the highest increase in surface area. All the experimental implants showed similar topographic properties both pre- and post-test. For most implants, no major changes occurred in surface topography on implantation. The procedure applied seems promising to evaluate the degradation of implant surface on insertion.

Development of PET/MRI with insertable PET for simultaneous PET and MR imaging of human brain.

PubMed

Jung, Jin Ho; Choi, Yong; Jung, Jiwoong; Kim, Sangsu; Lim, Hyun Keong; Im, Ki Chun; Oh, Chang Hyun; Park, Hyun-wook; Kim, Kyung Min; Kim, Jong Guk

2015-05-01

The purpose of this study was to develop a dual-modality positron emission tomography (PET)/magnetic resonance imaging (MRI) with insertable PET for simultaneous PET and MR imaging of the human brain. The PET detector block was composed of a 4 × 4 matrix of detector modules, each consisting of a 4 × 4 array LYSO coupled to a 4 × 4 Geiger-mode avalanche photodiode (GAPD) array. The PET insert consisted of 18 detector blocks, circularly mounted on a custom-made plastic base to form a ring with an inner diameter of 390 mm and axial length of 60 mm. The PET gantry was shielded with gold-plated conductive fabric tapes with a thickness of 0.1 mm. The charge signals of PET detector transferred via 4 m long flat cables were fed into the position decoder circuit. The flat cables were shielded with a mesh-type aluminum sheet with a thickness of 0.24 mm. The position decoder circuit and field programmable gate array-embedded DAQ modules were enclosed in an aluminum box with a thickness of 10 mm and located at the rear of the MR bore inside the MRI room. A 3-T human MRI system with a Larmor frequency of 123.7 MHz and inner bore diameter of 60 cm was used as the PET/MRI hybrid system. A custom-made radio frequency (RF) coil with an inner diameter of 25 cm was fabricated. The PET was positioned between gradient and the RF coils. PET performance was measured outside and inside the MRI scanner using echo planar imaging, spin echo, turbo spin echo, and gradient echo sequences. MRI performance was also evaluated with and without the PET insert. The stability of the newly developed PET insert was evaluated and simultaneous PET and MR images of a brain phantom were acquired. No significant degradation of the PET performance caused by MR was observed when the PET was operated using various MR imaging sequences. The signal-to-noise ratio of MR images was slightly degraded due to the PET insert installed inside the MR bore while the homogeneity was maintained. The change of gain of the 256 GAPD/scintillator elements of a detector block was <3% for 60 min, and simultaneous PET and MR images of a brain phantom were successfully acquired. Experimental results indicate that a compact and lightweight PET insert for hybrid PET/MRI can be developed using GAPD arrays and charge signal transmission method proposed in this study without significant interference.

Effects of scapular taping on the activity onset of scapular muscles and the scapular kinematics in volleyball players with rotator cuff tendinopathy.

PubMed

Leong, Hio Teng; Ng, Gabriel Yin-Fat; Fu, Siu Ngor

2017-06-01

To examine the effect of scapular taping on the activity onset of scapular muscles and the scapular kinematics during arm elevation in volleyball players with rotator cuff (RC) tendinopathy. Randomized placebo-controlled repeated measures METHODS: Twenty-six male volleyball players with RC tendinopathy (mean age=23.6±3.3years) participated in the study. Electromyography (EMG) activity onset of upper trapezius (UT), middle trapezius (MT), lower trapezius (LT) and serratus anterior (SA) and the three-dimensional scapular kinematics quantified by using an acromial marker cluster method were compared with three scapular taping protocols, namely, no taping, therapeutic taping, and placebo taping. The MT, LT and SA activated significantly earlier in both therapeutic taping (all p<0.005) and placebo taping conditions than no taping conditions (all p<0.002). There was a small increase in the scapular upward rotation when therapeutic taping and no taping conditions were compared (p=0.007). Scapular taping may enhance the neuromotor control of the scapular muscles. Whether it provides adequate support for normal scapular kinematics during arm movement in athletes with RC tendinopathy await for further studies. Copyright © 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Effect of tape recording on perturbation measures.

PubMed

Jiang, J; Lin, E; Hanson, D G

1998-10-01

Tape recorders have been shown to affect measures of voice perturbation. Few studies, however, have been conducted to quantitatively justify the use or exclusion of certain types of recorders in voice perturbation studies. This study used sinusoidal and triangular waves and synthesized vowels to compare perturbation measures extracted from directly digitized signals with those recorded and played back through various tape recorders, including 3 models of digital audio tape recorders, 2 models of analog audio cassette tape recorders, and 2 models of video tape recorders. Signal contamination for frequency perturbation values was found to be consistently minimal with digital recorders (percent jitter = 0.01%-0.02%), mildly increased with video recorders (0.05%-0.10%), moderately increased with a high-quality analog audio cassette tape recorder (0.15%), and most prominent with a low-quality analog audio cassette tape recorder (0.24%). Recorder effect on amplitude perturbation measures was lowest in digital recorders (percent shimmer = 0.09%-0.20%), mildly to moderately increased in video recorders and a high-quality analog audio cassette tape recorder (0.25%-0.45%), and most prominent in a low-quality analog audio cassette tape recorder (0.98%). The effect of cassette tape material, length of spooled tape, and duration of analysis were also tested and are discussed.

Three-Dimensional Rotation, Twist and Torsion Analyses Using Real-Time 3D Speckle Tracking Imaging: Feasibility, Reproducibility, and Normal Ranges in Pediatric Population.

PubMed

Zhang, Li; Zhang, Jing; Han, Wei; Gao, Jun; He, Lin; Yang, Yali; Yin, Ping; Xie, Mingxing; Ge, Shuping

2016-01-01

The specific aim of this study was to evaluate the feasibility, reproducibility and maturational changes of LV rotation, twist and torsion variables by real-time 3D speckle-tracking echocardiography (RT3DSTE) in children. A prospective study was conducted in 347 consecutive healthy subjects (181 males/156 females, mean age 7.12 ± 5.3 years, and range from birth to 18-years) using RT 3D echocardiography (3DE). The LV rotation, twist and torsion measurements were made off-line using TomTec software. Manual landmark selection and endocardial border editing were performed in 3 planes (apical "2"-, "4"-, and "3"- chamber views) and semi-automated tracking yielded LV rotation, twist and torsion measurements. LV rotation, twist and torsion analysis by RT 3DSTE were feasible in 307 out of 347 subjects (88.5%). There was no correlation between rotation or twist and age, height, weight, BSA or heart rate, respectively. However, there was statistically significant, but very modest correlation between LV torsion and age (R2 = 0.036, P< 0.001). The normal ranges were defined for rotation and twist in this cohort, and for torsion for each age group. The intra-observer and inter-observer variabilities for apical and basal rotation, twist and torsion ranged from 7.3% ± 3.8% to 12.3% ± 8.8% and from 8.8% ± 4.6% to 15.7% ± 10.1%, respectively. We conclude that analysis of LV rotation, twist and torsion by this new RT3D STE is feasible and reproducible in pediatric population. There is no maturational change in rotation and twist, but torsion decreases with age in this cohort. Further refinement is warranted to validate the utility of this new methodology in more sensitive and quantitative evaluation of congenital and acquired heart diseases in children.

Low-Frequency Interlayer Raman Modes to Probe Interface of Twisted Bilayer MoS 2

DOE PAGES

Huang, Shengxi; Liang, Liangbo; Ling, Xi; ...

2016-02-21

A variety of van der Waals homo- and hetero- structures assembled by stamping monolayers together present optoelectronic properties suitable for diverse applications. Understanding the details of the interlayer stacking and resulting coupling is crucial for tuning these properties. Twisted bilayer transition metal dichalcogenides offer a great platform for developing a precise understanding of the structure/property relationship. Here, we study the low-frequency interlayer shear and breathing Raman modes (<50 cm-1) in twisted bilayer MoS 2 by Raman spectroscopy and first-principles modeling. Twisting introduces both rotational and translational shifts and significantly alters the interlayer stacking and coupling, leading to notable frequency andmore » intensity changes of low-frequency modes. The frequency variation can be up to 8 cm-1 and the intensity can vary by a factor of ~5 for twisting near 0 and 60 , where the stacking is a mixture of multiple high-symmetry stacking patterns and is thus especially sensitive to twisting. Moreover, for twisting angles between 20 and 40 , the interlayer coupling is nearly constant since the stacking results in mismatched lattices over the entire sample. It follows that the Raman signature is relatively uniform. Interestingly, unlike the breathing mode, the shear mode is extremely sensitive to twisting: it disappears between 20 and 40 as its frequency drops to almost zero due to the stacking-induced mismatch. Note that for some samples, multiple breathing mode peaks appear, indicating non-uniform coupling across the interface. In contrast to the low-frequency interlayer modes, high-frequency intralayer Raman modes are much less sensitive to interlayer stacking and coupling, showing negligible changes upon twisting. Our research demonstrates the effectiveness of low-frequency Raman modes for probing the interfacial coupling and environment of twisted bilayer MoS2, and potentially other two-dimensional materials and heterostructures.« less

Twist1 Transcriptional Targets in the Developing Atrio-Ventricular Canal of the Mouse

PubMed Central

Vrljicak, Pavle; Cullum, Rebecca; Xu, Eric; Chang, Alex C. Y.; Wederell, Elizabeth D.; Bilenky, Mikhail; Jones, Steven J. M.; Marra, Marco A.; Karsan, Aly; Hoodless, Pamela A.

2012-01-01

Malformations of the cardiovascular system are the most common type of birth defect in humans, frequently affecting the formation of valves and septa. During heart valve and septa formation, cells from the atrio-ventricular canal (AVC) and outflow tract (OFT) regions of the heart undergo an epithelial-to-mesenchymal transformation (EMT) and invade the underlying extracellular matrix to give rise to endocardial cushions. Subsequent maturation of newly formed mesenchyme cells leads to thin stress-resistant leaflets. TWIST1 is a basic helix-loop-helix transcription factor expressed in newly formed mesenchyme cells of the AVC and OFT that has been shown to play roles in cell survival, cell proliferation and differentiation. However, the downstream targets of TWIST1 during heart valve formation remain unclear. To identify genes important for heart valve development downstream of TWIST1, we performed global gene expression profiling of AVC, OFT, atria and ventricles of the embryonic day 10.5 mouse heart by tag-sequencing (Tag-seq). Using this resource we identified a novel set of 939 genes, including 123 regulators of transcription, enriched in the valve forming regions of the heart. We compared these genes to a Tag-seq library from the Twist1 null developing valves revealing significant gene expression changes. These changes were consistent with a role of TWIST1 in controlling differentiation of mesenchymal cells following their transformation from endothelium in the mouse. To study the role of TWIST1 at the DNA level we performed chromatin immunoprecipitation and identified novel direct targets of TWIST1 in the developing heart valves. Our findings support a role for TWIST1 in the differentiation of AVC mesenchyme post-EMT in the mouse, and suggest that TWIST1 can exert its function by direct DNA binding to activate valve specific gene expression. PMID:22815831

An Experimental Examination of the Loss-of-Flow Accident Phenomenon for Prototypical ITER Divertor Channels of Y = 0 and Y = 2

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

Marshall, Theron D.; McDonald, Jimmie M.; Cadwallader, Lee C.

2000-01-15

This paper discusses the thermal response of two prototypical International Thermonuclear Experimental Reactor (ITER) divertor channels during simulated loss-of-flow-accident (LOFA) experiments. The thermal response was characterized by the time-to-burnout (TBO), which is a figure of merit on the mockups' survivability. Data from the LOFA experiments illustrate that (a) the pre-LOFA inlet velocity does not significantly influence the TBO, (b) the incident heat flux (IHF) does influence the TBO, and (c) a swirl tape insert significantly improves the TBO and promotes the initiation of natural circulation. This natural circulation enabled the mockup to absorb steady-state IHFs after the coolant circulation pumpmore » was disabled. Several methodologies for thermal-hydraulic modeling of the LOFA were attempted.« less

An experimental examination of the loss-of-flow accident phenomenon for prototypical ITER divertor channels of Y=0 and Y=2

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

Marshall, T.D.; McDonald, J.M.; Cadwallader, L.C.

2000-01-01

This paper discusses the thermal response of two prototypical International Thermonuclear Experimental Reactor (ITER) divertor channels during simulated loss-of-flow-accident (LOFA) experiments. The thermal response was characterized by the time-to-burnout (TBO), which is a figure of merit on the mockups' survivability. Data from the LOFA experiments illustrate that (a) the pre-LOFA inlet velocity does not significantly influence the TBO, (b) the incident heat flux (IHF) does influence the TBO, and (c) a swirl tape insert significantly improves the TBO and promotes the initiation of natural circulation. This natural circulation enabled the mockup to absorb steady-state IHFs after the coolant circulation pumpmore » was disabled. Several methodologies for thermal-hydraulic modeling of the LOFA were attempted.« less

Method of fabricating a microelectronic device package with an integral window

DOEpatents

Peterson, Kenneth A.; Watson, Robert D.

2003-01-01

A method of fabricating a microelectronic device package with an integral window for providing optical access through an aperture in the package. The package is made of a multilayered insulating material, e.g., a low-temperature cofired ceramic (LTCC) or high-temperature cofired ceramic (HTCC). The window is inserted in-between personalized layers of ceramic green tape during stackup and registration. Then, during baking and firing, the integral window is simultaneously bonded to the sintered ceramic layers of the densified package. Next, the microelectronic device is flip-chip bonded to cofired thick-film metallized traces on the package, where the light-sensitive side is optically accessible through the window. Finally, a cover lid is attached to the opposite side of the package. The result is a compact, low-profile package, flip-chip bonded, hermetically-sealed package having an integral window.

Experimental evidence for non-Abelian gauge potentials in twisted graphene bilayers

NASA Astrophysics Data System (ADS)

Yin, Long-Jing; Qiao, Jia-Bin; Zuo, Wei-Jie; Li, Wen-Tian; He, Lin

2015-08-01

Non-Abelian gauge potentials are quite relevant in subatomic physics, but they are relatively rare in a condensed matter context. Here we report the experimental evidence for non-Abelian gauge potentials in twisted graphene bilayers by scanning tunneling microscopy and spectroscopy. At a magic twisted angle, θ ≈(1.11±0.05 ) ∘ , a pronounced sharp peak, which arises from the nondispersive flat bands at the charge neutrality point, is observed in the tunneling density of states due to the action of the non-Abelian gauge fields. Moreover, we observe confined electronic states in the twisted bilayer, as manifested by regularly spaced tunneling peaks with energy spacing δ E ≈vF/D ≈70 meV (here vF is the Fermi velocity of graphene and D is the period of the moiré patterns). This indicates that the non-Abelian gauge potentials in twisted graphene bilayers confine low-energy electrons into a triangular array of quantum dots following the modulation of the moiré patterns. Our results also directly demonstrate that the Fermi velocity in twisted bilayers can be tuned from about 106m /s to zero by simply reducing the twisted angle of about 2∘.

Twist phase-induced characteristics changes of a radially polarized Gaussian Schell-Model beam in a uniaxial crystal orthogonal to the optical axis

NASA Astrophysics Data System (ADS)

Cao, Pengfei; Fu, Wenyu

2017-10-01

Based on the extended Huygens-Fresnel integral formula and unified theory of coherence and polarization, we obtained the cross-spectral density matrix elements for a radially polarized partially coherent twist (RPPCT) beam in a uniaxial crystal. Moreover, compared with free space, we explore numerically the evolution properties of a RPPCT beam in a uniaxial crystal. The calculation results show that the evolution properties of a RPPCT beam in crystals are substantially different from its properties in free space. These properties in crystals are mainly determined by the twist factor and the ratio of extraordinary index to ordinary refractive index. In a uniaxial crystal, the distribution of the intensity of a RPPCT beam all exhibits non-circular symmetry, and these distributions change with twist factor and the ratio of extraordinary index to ordinary refractive index. The twist factor affects their rotation orientation angles, and the ratio of extraordinary index to ordinary refractive index impacts their twisted levels. This novel characteristics can be used for free-space optical communications, particle manipulation and nonlinear optics, where partially coherent beam with controlled profile and twist factor are required.

The ISEE-3 ULEWAT: Flux tape description and heavy ion fluxes 1978-1984. [plasma diagnostics

NASA Technical Reports Server (NTRS)

Mason, G. M.; Klecker, B.

1985-01-01

The ISEE ULEWAT FLUX tapes contain ULEWAT and ISEE pool tape data summarized over relatively long time intervals (1hr) in order to compact the data set into an easily usable size. (Roughly 3 years of data fit onto one 1600 BPI 9-track magnetic tape). In making the tapes, corrections were made to the ULEWAT basic data tapes in order to, remove rate spikes and account for changes in instrument response so that to a large extent instrument fluxes can be calculated easily from the FLUX tapes without further consideration of instrument performance.

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

Ayala, Alicia; Corral, Erica L.; Loehman, Ronald E.

A tape casting procedure for fabricating ceramic magnesium oxide tapes has been developed as a method to produce flat sheets of sintered MgO that are thin and porous. Thickness of single layer tapes is in the range of 200-400 {micro}m with corresponding surface roughness values in the range of 10-20 {micro}m as measured by laser profilometry. Development of the tape casting technique required optimization of pretreatment for the starting magnesium oxide (MgO) powder as well as a detailed study of the casting slurry preparation and subsequent heat treatments for sintering and final tape flattening. Milling time of the ceramic powder,more » plasticizer, and binder mixture was identified as a primary factor affecting surface morphology of the tapes. In general, longer milling times resulted in green tapes with a noticeably smoother surface. This work demonstrates that meticulous control of the entire tape casting operation is necessary to obtain high-quality MgO tapes.« less

Tape tracking and handling for magnetic tape recorders. [aboard spacecraft

NASA Technical Reports Server (NTRS)

Paroby, W.; Disilvestre, R.

1975-01-01

One of the critical performance and life limiting elements of a spacecraft tape recorder instrumentation system which has received little attention in technical literature is magnetic tape tracking and handling technology. This technology is required to understand how to gently transfer tape from one reel to another with proper alignment and a desirable uniform velocity at the read and write transducer heads. The increased demand for high data rate (i.e., multi-track spacecraft recording instrumentation systems), coupled with performance under extreme environmental conditions, requires a thorough knowledge of the various parameters which establish an optimum designed tape tracking and handling system. Stress analysis techniques are required to evaluate these parameters substantiated with test tape tracking data, to show the effect of each parameter on a tape recorder instrumentation tracking system. The technology is applicable to ground type tape recorders where the detrimental effects of edge guidance can be eliminated.

A study of tape adhesive strength on endotracheal tubes.

PubMed

Fenje, N; Steward, D J

1988-03-01

A method of assessing the adhesive bond of tapes used to secure endotracheal (ET) tubes is described. Five kinds of tape and six different ET tubes including two silicone rubber, wire-reinforced tubes were tested. There are significant differences in the adhesive strength of different tapes, and in the adhesive bond formed by different ET tube materials. On the Portex clear ET tube, silk tape adhered best (p less than 0.001), followed by waterproof, cloth, dermiclear, and micropore tapes. Adhesive bonding by silk tape was significantly greater (p less than 0.001) for the three clear ET tubes (Portex clear, NCC clear, and Portex ivory) than for the Portex blue and the silicone rubber, wire-reinforced ET tubes. All tapes showed very poor or negligible adhesion to the Sheridan and Portex reinforced ET tubes. Adhesion to these tubes was greatly improved by wrapping them tightly with an "op site" dressing prior to applying tape.

Superconducting properties of multilayered Ag/Bi(Pb)-2223 tapes prepared using pretextured monolayered tapes

NASA Astrophysics Data System (ADS)

Syamaprasad, U.; Sarma, M. S.; Guruswamy, P.; Pillai, S. G. K.; Warrier, K. G. K.; Damodaran, A. D.

1997-02-01

Multilayered Ag/Bi(Pb)-2223 tapes with high critical current densities 0953-2048/10/2/005/img1 have been fabricated using partially heat treated, textured monolayered tapes. Cut sections of the monolayered tapes have been stacked one over the other and folded together using high-purity silver foil and further rolled and heat treated to obtain multilayered tapes of different thickness with an HTS layer thickness varying from 9 to 0953-2048/10/2/005/img2. A comparison of the superconducting properties of the multilayered tapes with those of monolayered tapes prepared under identical heat treatment conditions shows that the 0953-2048/10/2/005/img3 ratio at 77 K is as high as 0.57. The ratio is found to decrease with a decrease in the HTS core thickness of the multilayered tapes. XRD studies of `banana peeled' samples show that the monolayered tapes at the folding stage acquire a good degree of texturing. The relatively high value of the 0953-2048/10/2/005/img3 ratio obtained in the present case compared with those reported by the existing techniques is attributed to the use of pretextured monolayered tapes.

Tape functionality: sonographic tape characteristics and outcome after TVT incontinence surgery.

PubMed

Kociszewski, Jacek; Rautenberg, Oliver; Perucchini, Daniele; Eberhard, Jakob; Geissbühler, Verena; Hilgers, Reinhard; Viereck, Volker

2008-01-01

To investigate tension-free vaginal tape (TVT) position and shape using ultrasound (US) and correlate the findings to outcome. The results of TVT surgery were investigated in 72 women with urodynamic stress urinary incontinence. The main outcome parameters were US tape position in relation to the urethra and dynamic changes in TVT shape at rest and during straining. Sixty-two patients (86%) were continent, 6 (8%) significantly improved, and the operation failed in four cases (6%). The median tape position was at 66% of the urethral length measured by US. The median tape-urethra-lumen distance was 3.8 mm at rest. Tape placement in the upper or lower quarter of the urethra was associated with a higher failure rate. Tapes positioned less than 3 mm from the urethra significantly increased postoperative complications (P < 0.0001). The tape was flat at rest and curved during straining in 44 (61%) patients; 98% (43/44) of these women were continent after surgery. An unchanged tape shape was associated with a poorer outcome (P = 0.00038). Patients with a flat tape at rest and during straining failed in 25% and patients with a permanent curved shape in 10%. TVT position relative to the patient's urethra seems to play a role in treatment outcome. Outcome was best in patients with dynamic change in tape shape during straining and location of the tape at the junction between the lower and middle urethra and at least 3 mm from the urethral lumen. (c) 2008 Wiley-Liss, Inc.

Statistical mechanics of ribbons under bending and twisting torques.

PubMed

Sinha, Supurna; Samuel, Joseph

2013-11-20

We present an analytical study of ribbons subjected to an external torque. We first describe the elastic response of a ribbon within a purely mechanical framework. We then study the role of thermal fluctuations in modifying its elastic response. We predict the moment-angle relation of bent and twisted ribbons. Such a study is expected to shed light on the role of twist in DNA looping and on bending elasticity of twisted graphene ribbons. Our quantitative predictions can be tested against future single molecule experiments.

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

Kleinert, J.; Haimberger, C.; Zabawa, P. J.

We describe the realization of a dc electric-field trap for ultracold polar molecules, the thin-wire electrostatic trap (TWIST). The thin wires that form the electrodes of the TWIST allow us to superimpose the trap onto a magneto-optical trap (MOT). In our experiment, ultracold polar NaCs molecules in their electronic ground state are created in the MOT via photoassociation, achieving a continuous accumulation in the TWIST of molecules in low-field seeking states. Initial measurements show that the TWIST trap lifetime is limited only by the background pressure in the chamber.

Morphing wing structure with controllable twist based on adaptive bending-twist coupling

NASA Astrophysics Data System (ADS)

Raither, Wolfram; Heymanns, Matthias; Bergamini, Andrea; Ermanni, Paolo

2013-06-01

A novel semi-passive morphing airfoil concept based on variable bending-twist coupling induced by adaptive shear center location and torsional stiffness is presented. Numerical parametric studies and upscaling show that the concept relying on smart materials permits effective twist control while offering the potential of being lightweight and energy efficient. By means of an experimental characterization of an adaptive beam and a scaled adaptive wing structure, effectiveness and producibility of the structural concept are demonstrated.

Cytoplasmic expression of Twist1, an EMT-related transcription factor, is associated with higher grades renal cell carcinomas and worse progression-free survival in clear cell renal cell carcinoma.

PubMed

Rasti, Arezoo; Madjd, Zahra; Abolhasani, Maryam; Mehrazma, Mitra; Janani, Leila; Saeednejad Zanjani, Leili; Asgari, Mojgan

2018-05-01

Twist1 is a key transcription factor, which confers tumor cells with cancer stem cell (CSC)-like characteristics and enhances epithelial-mesenchymal transition in pathological conditions including tumor malignancy and metastasis. This study aimed to evaluate the expression patterns and clinical significance of Twist1 in renal cell carcinoma (RCC). The cytoplasmic and nuclear expression of Twist1 were examined in 252 well-defined renal tumor tissues, including 173 (68.7%) clear cell renal cell carcinomas (ccRCC), 45 (17.9%) papillary renal cell carcinomas (pRCC) and 34 (13.5%) chromophobe renal cell carcinoma, by immunohistochemistry on a tissue microarray. The association between expression of this marker and clinicopathologic parameters and survival outcomes were then analyzed. Twist1 was mainly localized to the cytoplasm of tumor cells (98.8%). Increased cytoplasmic expression of Twist1 was associated with higher grade tumors (P = 0.045), renal vein invasion (P = 0.031) and microvascular invasion (P = 0.044) in RCC. It was positively correlated with higher grade tumors (P = 0.026), shorter progression-free survival time (P = 0.027) in patients with ccRCC, and also with higher stage in pRCC patients (P = 0.036). Significantly higher cytoplasmic expression levels of Twist1 were found in ccRCC and pRCC subtypes, due to their more aggressive tumor behavior. Increased cytoplasmic expression of Twist1 had a critical role in worse prognosis in ccRCC. These findings suggest that cytoplasmic, rather than nuclear expression of Twist1 can be considered as a prognostic and therapeutic marker for targeted therapy of RCC, especially for ccRCC patients.

Metallographic autopsies of full-scale ITER prototype cable-in-conduit conductors after full cyclic testing in SULTAN: II. Significant reduction of strand movement and strand damage in short twist pitch CICCs

DOE PAGES

Sanabria, Charlos; Lee, Peter J.; Starch, William; ...

2015-10-14

Prototype cable in conduit conductors (CICCs) destined for use in the Toroidal Field (TF) and Central Solenoid (CS) coils of the ITER experimental fusion reactor underwent severe cyclic loading in the SULTAN facility. Their autopsies revealed significant and permanent transverse strand migration due to the large Lorentz forces of the SULTAN test. The movement resulted in a 3 7% void fraction increase on the Low Pressure (LP) side of the longer twist pitch CICCs. However, short twist pitch conductors exhibited less than 1% void fraction increase in the LP side, as well as a complete absence of the Nb 3Snmore » filament fractures observed in the longer twist pitch conductors. We report here a detailed strand to cable analysis of short and longer “baseline” twist pitch CICCs. It was found that the use of Internal Tin strands in the longer “baseline” twist pitch CICCs can be beneficial possibly because of their superior stiffness—which better resist strand movement—while the use of Bronze Process strands showed more movement and poorer cyclic test performance. This was not the case for the short twist pitch CICC. Such conductor design seems to work well with both strand types. But it was found that despite the absence of filament fractures, the short twist pitch CICC made from the Internal Tin strands studied here developed severe strand distortion during cabling which resulted in diffusion barrier breaks and Sn contamination of the Cu stabilizer during the heat treatment. Furthermore, the short twist pitch CICC made from Bronze Process strands preserved diffusion barrier integrity.« less

Analysis of a Caenorhabditis elegans Twist homolog identifies conserved and divergent aspects of mesodermal patterning

PubMed Central

Harfe, Brian D.; Gomes, Ana Vaz; Kenyon, Cynthia; Liu, Jun; Krause, Michael; Fire, Andrew

1998-01-01

Mesodermal development is a multistep process in which cells become increasingly specialized to form specific tissue types. In Drosophila and mammals, proper segregation and patterning of the mesoderm involves the bHLH factor Twist. We investigated the activity of a Twist-related factor, CeTwist, during Caenorhabditis elegans mesoderm development. Embryonic mesoderm in C. elegans derives from a number of distinct founder cells that are specified during the early lineages; in contrast, a single blast cell (M) is responsible for all nongonadal mesoderm formation during postembryonic development. Using immunofluorescence and reporter fusions, we determined the activity pattern of the gene encoding CeTwist. No activity was observed during specification of mesodermal lineages in the early embryo; instead, the gene was active within the M lineage and in a number of mesodermal cells with nonstriated muscle fates. A role for CeTwist in postembryonic mesodermal cell fate specification was indicated by ectopic expression and genetic interference assays. These experiments showed that CeTwist was responsible for activating two target genes normally expressed in specific subsets of nonstriated muscles derived from the M lineage. In vitro and in vivo assays suggested that CeTwist cooperates with the C. elegans E/Daughterless homolog in directly activating these targets. The two target genes that we have studied, ceh-24 and egl-15, encode an NK-2 class homeodomain and an FGF receptor (FGFR) homolog, respectively. Twist activates FGFR and NK-homeodomain target genes during mesodermal patterning of Drosophila and similar target interactions have been proposed to modulate mesenchymal growth during closure of the vertebrate skull. These results suggest the possibility that a conserved pathway may be used for diverse functions in mesodermal specification. PMID:9716413

Metallographic autopsies of full-scale ITER prototype cable-in-conduit conductors after full cyclic testing in SULTAN: II. Significant reduction of strand movement and strand damage in short twist pitch CICCs

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

Sanabria, Charlos; Lee, Peter J.; Starch, William

Prototype cable in conduit conductors (CICCs) destined for use in the Toroidal Field (TF) and Central Solenoid (CS) coils of the ITER experimental fusion reactor underwent severe cyclic loading in the SULTAN facility. Their autopsies revealed significant and permanent transverse strand migration due to the large Lorentz forces of the SULTAN test. The movement resulted in a 3 7% void fraction increase on the Low Pressure (LP) side of the longer twist pitch CICCs. However, short twist pitch conductors exhibited less than 1% void fraction increase in the LP side, as well as a complete absence of the Nb 3Snmore » filament fractures observed in the longer twist pitch conductors. We report here a detailed strand to cable analysis of short and longer “baseline” twist pitch CICCs. It was found that the use of Internal Tin strands in the longer “baseline” twist pitch CICCs can be beneficial possibly because of their superior stiffness—which better resist strand movement—while the use of Bronze Process strands showed more movement and poorer cyclic test performance. This was not the case for the short twist pitch CICC. Such conductor design seems to work well with both strand types. But it was found that despite the absence of filament fractures, the short twist pitch CICC made from the Internal Tin strands studied here developed severe strand distortion during cabling which resulted in diffusion barrier breaks and Sn contamination of the Cu stabilizer during the heat treatment. Furthermore, the short twist pitch CICC made from Bronze Process strands preserved diffusion barrier integrity.« less

Interaction between left ventricular twist mechanics and arterial haemodynamics during localised, non-metabolic hyperaemia with and without blood flow restriction.

PubMed

van Mil, Anke C C M; Pearson, James; Drane, Aimee L; Cockcroft, John R; McDonnell, Barry J; Stöhr, Eric J

2016-04-01

What is the central question of this study? Left ventricular (LV) twist is reduced when afterload is increased, but the meaning of this specific heart muscle response and its impact on cardiac output are not well understood. What is the main finding and its importance? This study shows that LV twist responds even when arterial haemodynamics are altered only locally, and without apparent change in metabolic (i.e. heat-induced) demand. The concurrent decline in cardiac output and LV twist during partial arterial occlusion despite the increased peripheral demand caused by heat stress suggests that LV twist may be involved in the protective sensing of heart muscle stress that can override the provision of the required cardiac output. Whether left ventricular (LV) twist and untwisting rate (LV twist mechanics) respond to localised, peripheral, non-metabolic changes in arterial haemodynamics within an individual's normal afterload range is presently unknown. Furthermore, previous studies indicate that LV twist mechanics may override the provision of cardiac output, but this hypothesis has not been examined purposefully. Therefore, we acutely altered local peripheral arterial haemodynamics in 11 healthy humans (women/men n = 3/8; age 26 ± 5 years) by bilateral arm heating (BAH). Ultrasonography was used to examine arterial haemodynamics, LV twist mechanics and the twist-to-shortening ratio (TSR). To determine the arterial function-dependent contribution of LV twist mechanics to cardiac output, partial blood flow restriction to the arms was applied during BAH (BAHBFR ). Bilateral arm heating increased arm skin temperatures [change (Δ) +6.4 ± 0.9°C, P < 0.0001] but not core temperature (Δ -0.0 ± 0.1°C, P > 0.05), concomitant to increases in brachial artery blood flow (Δ 212 ± 77 ml, P < 0.0001), cardiac output (Δ 495 ± 487 l min(-1) , P < 0.05), LV twist (Δ 3.0 ± 3.5 deg, P < 0.05) and TSR (Δ 3.3 ± 1.3, P < 0.05) but maintained carotid artery blood flow (Δ 18 ± 147 ml, P > 0.05). Subsequently, BAHBFR reduced all parameters to preheating levels, except for TSR and heart rate, which remained at BAH levels. In conclusion, LV twist mechanics responded to local peripheral arterial haemodynamics within the normal afterload range, in part independent of TSR and heart rate. The findings suggest that LV twist mechanics may be more closely associated with intrinsic sensing of excessive pressure stress rather than being associated with the delivery of adequate cardiac output. © 2016 The Authors. Experimental Physiology © 2016 The Physiological Society.

Fermion number of twisted kinks in the NJL2 model revisited

NASA Astrophysics Data System (ADS)

Thies, Michael

2018-03-01

As a consequence of axial current conservation, fermions cannot be bound in localized lumps in the massless Nambu-Jona-Lasinio model. In the case of twisted kinks, this manifests itself in a cancellation between the valence fermion density and the fermion density induced in the Dirac sea. To attribute the correct fermion number to these bound states requires an infrared regularization. Recently, this has been achieved by introducing a bare fermion mass, at least in the nonrelativistic regime of small twist angles and fermion numbers. Here, we propose a simpler regularization using a finite box which preserves integrability and can be applied at any twist angle. A consistent and physically plausible assignment of fermion number to all twisted kinks emerges.

An empirically-based model for the lift coefficients of twisted airfoils with leading-edge tubercles

NASA Astrophysics Data System (ADS)

Ni, Zao; Su, Tsung-chow; Dhanak, Manhar

2018-04-01

Experimental data for untwisted airfoils are utilized to propose a model for predicting the lift coefficients of twisted airfoils with leading-edge tubercles. The effectiveness of the empirical model is verified through comparison with results of a corresponding computational fluid-dynamic (CFD) study. The CFD study is carried out for both twisted and untwisted airfoils with tubercles, the latter shown to compare well with available experimental data. Lift coefficients of twisted airfoils predicted from the proposed empirically-based model match well with the corresponding coefficients determined using the verified CFD study. Flow details obtained from the latter provide better insight into the underlying mechanism and behavior at stall of twisted airfoils with leading edge tubercles.

Main image file tape description

USGS Publications Warehouse

Warriner, Howard W.

1980-01-01

This Main Image File Tape document defines the data content and file structure of the Main Image File Tape (MIFT) produced by the EROS Data Center (EDC). This document also defines an INQUIRY tape, which is just a subset of the MIFT. The format of the INQUIRY tape is identical to the MIFT except for two records; therefore, with the exception of these two records (described elsewhere in this document), every remark made about the MIFT is true for the INQUIRY tape.

"Twisted Beam" SEE Observations of Ionospheric Heating from HAARP

NASA Astrophysics Data System (ADS)

Briczinski, S. J.; Bernhardt, P. A.; Siefring, C. L.; Han, S.-M.; Pedersen, T. R.; Scales, W. A.

2015-10-01

Nonlinear interactions of high power HF radio waves in the ionosphere provide aeronomers with a unique space-based laboratory capability. The High-Frequency Active Auroral Research Program (HAARP) in Gakona, Alaska is the world's largest heating facility, yielding effective radiated powers in the gigawatt range. New results are present from HAARP experiments using a "twisted beam" excitation mode. Analysis of twisted beam heating shows that the SEE results obtained are identical to more traditional patterns. One difference in the twisted beam mode is the heating region produced is in the shape of a ring as opposed to the more traditional "solid spot" region from a pencil beam. The ring heating pattern may be more conducive to the creation of stable artificial airglow layers because of the horizontal structure of the ring. The results of these runs include artificial layer creation and evolution as pertaining to the twisted beam pattern. The SEE measurements aid the interpretation of the twisted beam interactions in the ionosphere.

Structures of Highly Twisted Amides Relevant to Amide N-C Cross-Coupling: Evidence for Ground-State Amide Destabilization.

PubMed

Pace, Vittorio; Holzer, Wolfgang; Meng, Guangrong; Shi, Shicheng; Lalancette, Roger; Szostak, Roman; Szostak, Michal

2016-10-04

Herein, we show that acyclic amides that have recently enabled a series of elusive transition-metal-catalyzed N-C activation/cross-coupling reactions are highly twisted around the N-C(O) axis by a new destabilization mechanism of the amide bond. A unique effect of the N-glutarimide substituent, leading to uniformly high twist (ca. 90°) irrespective of the steric effect at the carbon side of the amide bond has been found. This represents the first example of a twisted amide that does not bear significant steric hindrance at the α-carbon atom. The (15) N NMR data show linear correlations between electron density at nitrogen and amide bond twist. This study strongly supports the concept of amide bond ground-state twist as a blueprint for activation of amides toward N-C bond cleavage. The new mechanism offers considerable opportunities for organic synthesis and biological processes involving non-planar amide bonds. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The association between left ventricular twisting motion and mechanical dyssynchrony: a three-dimensional speckle tracking study.

PubMed

Fujiwara, Shohei; Komamura, Kazuo; Nakabo, Ayumi; Masaki, Mitsuru; Fukui, Miho; Sugahara, Masataka; Itohara, Kanako; Soyama, Yuko; Goda, Akiko; Hirotani, Shinichi; Mano, Toshiaki; Masuyama, Tohru

2016-02-01

Left ventricular (LV) dyssynchrony is a causal factor in LV dysfunction and thought to be associated with LV twisting motion. We tested whether three-dimensional speckle tracking (3DT) can be used to evaluate the relationship between LV twisting motion and dyssynchrony. We examined 25 patients with sick sinus syndrome who had received dual chamber pacemakers. The acute effects of ventricular pacing on LV wall motion after the switch from atrial to ventricular pacing were assessed. LV twisting motion and dyssynchrony during each pacing mode were measured using 3DT. LV dyssynchrony was calculated from the time to the minimum peak systolic area strain of 16 LV imaging segments. Ventricular pacing increased LV dyssynchrony and decreased twist and torsion. A significant correlation was observed between changes in LV dyssynchrony and changes in torsion (r = -0.65, p < 0.01). Evaluation of LV twisting motion can potentially be used for diagnosing LV dyssynchrony.

Twisted electron-acoustic waves in plasmas

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

Aman-ur-Rehman, E-mail: amansadiq@gmail.com; Department of Physics and Applied Mathematics; Ali, S.

2016-08-15

In the paraxial limit, a twisted electron-acoustic (EA) wave is studied in a collisionless unmagnetized plasma, whose constituents are the dynamical cold electrons and Boltzmannian hot electrons in the background of static positive ions. The analytical and numerical solutions of the plasma kinetic equation suggest that EA waves with finite amount of orbital angular momentum exhibit a twist in its behavior. The twisted wave particle resonance is also taken into consideration that has been appeared through the effective wave number q{sub eff} accounting for Laguerre-Gaussian mode profiles attributed to helical phase structures. Consequently, the dispersion relation and the damping ratemore » of the EA waves are significantly modified with the twisted parameter η, and for η → ∞, the results coincide with the straight propagating plane EA waves. Numerically, new features of twisted EA waves are identified by considering various regimes of wavelength and the results might be useful for transport and trapping of plasma particles in a two-electron component plasma.« less

Kinetic study of ion acoustic twisted waves with kappa distributed electrons

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

Arshad, Kashif, E-mail: kashif.arshad.butt@gmail.com; Aman-ur-Rehman, E-mail: amansadiq@gmail.com; Mahmood, Shahzad, E-mail: shahzadm100@gmail.com

2016-05-15

The kinetic theory of Landau damping of ion acoustic twisted modes is developed in the presence of orbital angular momentum of the helical (twisted) electric field in plasmas with kappa distributed electrons and Maxwellian ions. The perturbed distribution function and helical electric field are considered to be decomposed by Laguerre-Gaussian mode function defined in cylindrical geometry. The Vlasov-Poisson equation is obtained and solved analytically to obtain the weak damping rates of the ion acoustic twisted waves in a non-thermal plasma. The strong damping effects of ion acoustic twisted waves at low values of temperature ratio of electrons and ions aremore » also obtained by using exact numerical method and illustrated graphically, where the weak damping wave theory fails to explain the phenomenon properly. The obtained results of Landau damping rates of the twisted ion acoustic wave are discussed at different values of azimuthal wave number and non-thermal parameter kappa for electrons.« less

Modeling and development of a twisting wing using inductively heated shape memory alloy actuators

NASA Astrophysics Data System (ADS)

Saunders, Robert N.; Hartl, Darren J.; Boyd, James G.; Lagoudas, Dimitris C.

2015-04-01

Wing twisting has been shown to improve aircraft flight performance. The potential benefits of a twisting wing are often outweighed by the mass of the system required to twist the wing. Shape memory alloy (SMA) actuators repeatedly demonstrate abilities and properties that are ideal for aerospace actuation systems. Recent advances have shown an SMA torsional actuator that can be manufactured and trained with the ability to generate large twisting deformations under substantial loading. The primary disadvantage of implementing large SMA actuators has been their slow actuation time compared to conventional actuators. However, inductive heating of an SMA actuator allows it to generate a full actuation cycle in just seconds rather than minutes while still . The aim of this work is to demonstrate an experimental wing being twisted to approximately 10 degrees by using an inductively heated SMA torsional actuator. This study also considers a 3-D electromagnetic thermo-mechanical model of the SMA-wing system and compare these results to experiments to demonstrate modeling capabilities.

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.

Hover Testing of the NASA/Army/MIT Active Twist Rotor Prototype Blade

NASA Technical Reports Server (NTRS)

Wilbur, Matthew L.; Yeager, William T., Jr.; Wilkie, W. Keats; Cesnik, Carlos E. S.; Shin, Sangloon

2000-01-01

Helicopter rotor individual blade control promises to provide a mechanism for increased rotor performance and reduced rotorcraft vibrations and noise. Active material methods, such as piezoelectrically actuated trailing-edge flaps and strain-induced rotor blade twisting, provide a means of accomplishing individual blade control without the need for hydraulic power in the rotating system. Recent studies have indicated that controlled strain induced blade twisting can be attained using piezoelectric active fiber composite technology. In order to validate these findings experimentally, a cooperative effort between NASA Langley Research Center, the Army Research Laboratory, and the MIT Active Materials and Structures Laboratory has been developed. As a result of this collaboration an aeroelastically-scaled active-twist model rotor blade has been designed and fabricated for testing in the heavy gas environment of the Langley Transonic Dynamics Tunnel (TDT). The results of hover tests of the active-twist prototype blade are presented in this paper. Comparisons with applicable analytical predictions of active-twist frequency response in hovering flight are also presented.

Feasibility model of a high reliability five-year tape transport. Volume 3: Appendices. [detailed drawing and analytical tools used in analyses

NASA Technical Reports Server (NTRS)

Meyers, A. P.; Davidson, W. A.; Gortowski, R. C.

1973-01-01

Detailed drawings of the five year tape transport are presented. Analytical tools used in the various analyses are described. These analyses include: tape guidance, tape stress over crowned rollers, tape pack stress program, response (computer) program, and control system electronics description.

Chemical News Via Audio Tapes: Chemical Industry News

ERIC Educational Resources Information Center

Hanford, W. E.; And Others

1972-01-01

Tape coverage of internal R&D news now has a broader scope with improved features. A new tape series covering external news of broad interest has been initiated. The use of tape in a Continuing Education Program is discussed as the future plans for expanding the audio tape program. (1 reference) (Author)

Educational Uses of Cartridge Tapes. Dissemination Document No. 11.

ERIC Educational Resources Information Center

Levine, S. Joseph

Tape cartridges for use by special education teachers are analyzed according to design, effective use, and availability. Basic operating principles of cassette and continuous loop tape cartridges are described and illustrated. Advantages of tape cartridges are indicated, such as the following: the position is saved on tape during student timeouts,…

Digital tape unit test facility software

NASA Technical Reports Server (NTRS)

Jackson, J. T.

1971-01-01

Two computer programs are described which are used for the collection and analysis of data from the digital tape unit test facility (DTUTF). The data are the recorded results of skew tests made on magnetic digital tapes which are used on computers as input/output media. The results of each tape test are keypunched onto an 80 column computer card. The format of the card is checked and the card image is stored on a master summary tape via the DTUTF card checking and tape updating system. The master summary tape containing the results of all the tape tests is then used for analysis as input to the DTUTF histogram generating system which produces a histogram of skew vs. date for selected data, followed by some statistical analysis of the data.

Forensic utility of the carbon isotope ratio of PVC tape backings

NASA Astrophysics Data System (ADS)

Stern, L. A.; Thompson, A. H.; Mehltretter, A. H.; McLaskey, V.; Parish, A.; Aranda, R.

2008-12-01

Forensic interest in adhesive tapes with PVC-backings (polyvinyl chloride, electrical tapes) derives from their use in construction of improvised explosive devices, drug packaging and in a variety of other illicit activities. Due to the range of physical characteristics and chemical compositions of such tapes, traditional microscopic and chemical analysis of the tape backings and adhesives offer a high degree of discrimination between tapes from different manufacturers and products. To evaluate whether carbon isotope ratios may be able to increase discrimination of electrical tapes, particularly with regards to different tapes of the same product, we assessed the PVC-backings of 87 rolls of black electrical tape for their δ13C values. The adhesive on these tapes was physically removed with hexane, and plasticizers within the PVC tape backings were removed by three-20 minute extractions with chloroform. The δ13C values of the PVC tape backings ranged between -23.8 and -41.5 (‰ V-PDB). The carbon isotopic variation within a product (identical brand and product identification) is significant, based on five products with at least 3 rolls (ranges of 7.4‰ (n=3), 10.0‰ (n=6), 4.2‰ (n=16), 3.8‰ (n=6), and 11.5‰ (n=8), respectively). There was no measurable carbon isotope variation in regards to the following: a) along the length of a roll (4 samples from 1 roll); b) between the center and edge of a strip of tape (1 pair); c) between rolls assumed to be from the same lot of tape (2 pairs); d) between different rolls from the same batch of tape (same product purchased at the same time and place; 5 pairs); and e) between samples of a tape at room temperature, heated to 50° C and 80° C for 1 week. For each sample within the population of 87 tapes, carbon isotopes alone exclude 80 to 100% of the tapes as a potential match, with an average exclusion power of 92.5%, using a window of ± 0.4‰. Carbon isotope variations originate from variations in starting materials and recycling reactants during manufacture; as a result, tapes may be otherwise physically and chemical indistinguishable, but may have distinct carbon isotope ratios. We compared the carbon isotope ratios of 6 pairs of pre- and post-blast samples of PVC tapes adhered to explosive charges. The carbon isotope ratios of the post-blast samples were 0 to 0.5 ‰ higher than the corresponding pre-blast samples. Possible causes of this carbon isotope increase may be the reaction of the plasticizer and/or adhesive with the PVC backing during the explosion or the addition of debris to the tape backing during the explosion. Even with these minor explosive-induced carbon isotope alterations, the δ13C values of post-blast PVC tape backings were similar enough to the starting material to make carbon isotope ratios of post-blast tape a useful forensic tool. The range of carbon isotope ratios that would be used to exclude potential matches would have to be larger for post-blast samples, but with a 17 ‰ range in the population, this approach may still be useful for post-blast tape samples.

Reaction mechanism of the acidic hydrolysis of highly twisted amides: Rate acceleration caused by the twist of the amide bond.

PubMed

Mujika, Jon I; Formoso, Elena; Mercero, Jose M; Lopez, Xabier

2006-08-03

We present an ab initio study of the acid hydrolysis of a highly twisted amide and a planar amide analogue. The aim of these studies is to investigate the effect that the twist of the amide bond has on the reaction barriers and mechanism of acid hydrolysis. Concerted and stepwise mechanisms were investigated using density functional theory and polarizable continuum model calculations. Remarkable differences were observed between the mechanism of twisted and planar amide, due mainly to the preference for N-protonation of the former and O-protonation of the latter. In addition, we were also able to determine that the hydrolytic mechanism of the twisted amide will be pH dependent. Thus, there is a preference for a stepwise mechanism with formation of an intermediate in the acid hydrolysis, whereas the neutral hydrolysis undergoes a concerted-type mechanism. There is a nice agreement between the characterized intermediate and available X-ray data and a good agreement with the kinetically estimated rate acceleration of hydrolysis with respect to analogous undistorted amide compounds. This work, along with previous ab initio calculations, describes a complex and rich chemistry for the hydrolysis of highly twisted amides as a function of pH. The theoretical data provided will allow for a better understanding of the available kinetic data of the rate acceleration of amides upon twisting and the relation of the observed rate acceleration with intrinsic differential reactivity upon loss of amide bond resonance.

Enhanced intersystem crossing in core-twisted aromatics.

PubMed

Nagarajan, Kalaivanan; Mallia, Ajith R; Muraleedharan, Keerthi; Hariharan, Mahesh

2017-03-01

We describe the design, bottom-up synthesis and X-ray single crystal structure of systematically twisted aromatics 1c and 2d for efficient intersystem crossing. Steric congestion at the cove region creates a nonplanar geometry that induces a significant yield of triplet excited states in the electron-poor core-twisted aromatics 1c and 2d . A systematic increase in the number of twisted regions in 1c and 2d results in a concomitant enhancement in the rate and yield of intersystem crossing, monitored using femtosecond and nanosecond transient absorption spectroscopy. Time-resolved absorption spectroscopic measurements display enhanced triplet quantum yields ( Φ T = 10 ± 1% for 1c and Φ T = 30 ± 2% for 2d ) in the twisted aromatics when compared to a negligible Φ T (<1%) in the planar analog 3c . Twist-induced spin-orbit coupling via activated out-of-plane C-H/C 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 C vibrations can facilitate the formation of triplet excited states in twisted aromatics 1c and 2d , in contrast to the negligible intersystem crossing in the planar analog 3c . The ease of synthesis, high solubility, access to triplet excited states and strong electron affinity make such imide functionalized core-twisted aromatics desirable materials for organic electronics such as solar cells.

Chirality-controlled spontaneous twisting of crystals due to thermal topochemical reaction.

PubMed

Rai, Rishika; Krishnan, Baiju P; Sureshan, Kana M

2018-03-20

Crystals that show mechanical response against various stimuli are of great interest. These stimuli induce polymorphic transitions, isomerizations, or chemical reactions in the crystal and the strain generated between the daughter and parent domains is transcribed into mechanical response. We observed that the crystals of modified dipeptide LL (N 3 -l-Ala-l-Val-NHCH 2 C≡CH) undergo spontaneous twisting to form right-handed twisted crystals not only at room temperature but also at 0 °C over time. Using various spectroscopic techniques, we have established that the twisting is due to the spontaneous topochemical azide-alkyne cycloaddition (TAAC) reaction at room temperature or lower temperatures. The rate of twisting can be increased by heating, exploiting the faster kinetics of the TAAC reaction at higher temperatures. To address the role of molecular chirality in the direction of twisting the enantiomer of dipeptide LL, N 3 -d-Ala-d-Val-NHCH 2 C≡CH (DD), was synthesized and topochemical reactivity and mechanoresponse of its crystals were studied. We have found that dipeptide DD not only underwent TAAC reaction, giving 1,4-triazole-linked pseudopolypeptides of d-amino acids, but also underwent twisting with opposite handedness (left-handed twisting), establishing the role of molecular chirality in controlling the direction of mechanoresponse. This paper reports ( i ) a mechanical response due to a thermal reaction and ( ii ) a spontaneous mechanical response in crystals and ( iii ) explains the role of molecular chirality in the handedness of the macroscopic mechanical response.

Design and analysis of variable-twist tiltrotor blades using shape memory alloy hybrid composites

NASA Astrophysics Data System (ADS)

Park, Jae-Sang; Kim, Seong-Hwan; Jung, Sung Nam; Lee, Myeong-Kyu

2011-01-01

The tiltrotor blade, or proprotor, acts as a rotor in the helicopter mode and as a propeller in the airplane mode. For a better performance, the proprotor should have different built-in twist distributions along the blade span, suitable for each operational mode. This paper proposes a new variable-twist proprotor concept that can adjust the built-in twist distribution for given flight modes. For a variable-twist control, the present proprotor adopts shape memory alloy hybrid composites (SMAHC) containing shape memory alloy (SMA) wires embedded in the composite matrix. The proprotor of the Korea Aerospace Research Institute (KARI) Smart Unmanned Aerial Vehicle (SUAV), which is based on the tiltrotor concept, is used as a baseline proprotor model. The cross-sectional properties of the variable-twist proprotor are designed to maintain the cross-sectional properties of the original proprotor as closely as possible. However, the torsion stiffness is significantly reduced to accommodate the variable-twist control. A nonlinear flexible multibody dynamic analysis is employed to investigate the dynamic characteristics of the proprotor such as natural frequency and damping in the whirl flutter mode, the blade structural loads in a transition flight and the rotor performance in hover. The numerical results show that the present proprotor is designed to have a strong similarity to the baseline proprotor in dynamic and load characteristics. It is demonstrated that the present proprotor concept could be used to improve the hover performance adaptively when the variable-twist control using the SMAHC is applied appropriately.

High current density electropolishing in the preparation of highly smooth substrate tapes for coated conductors

DOEpatents

Kreiskott, Sascha [Los Alamos, NM; Matias, Vladimir [Santa Fe, NM; Arendt, Paul N [Los Alamos, NM; Foltyn, Stephen R [Los Alamos, NM; Bronisz, Lawrence E [Los Alamos, NM

2009-03-31

A continuous process of forming a highly smooth surface on a metallic tape by passing a metallic tape having an initial roughness through an acid bath contained within a polishing section of an electropolishing unit over a pre-selected period of time, and, passing a mean surface current density of at least 0.18 amperes per square centimeter through the metallic tape during the period of time the metallic tape is in the acid bath whereby the roughness of the metallic tape is reduced. Such a highly smooth metallic tape can serve as a base substrate in subsequent formation of a superconductive coated conductor.

Methods and systems for fabricating high quality superconducting tapes

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

Majkic, Goran; Selvamanickam, Venkat

An MOCVD system fabricates high quality superconductor tapes with variable thicknesses. The MOCVD system can include a gas flow chamber between two parallel channels in a housing. A substrate tape is heated and then passed through the MOCVD housing such that the gas flow is perpendicular to the tape's surface. Precursors are injected into the gas flow for deposition on the substrate tape. In this way, superconductor tapes can be fabricated with variable thicknesses, uniform precursor deposition, and high critical current densities.

Thermoplastic tape compaction device

DOEpatents

Campbell, Vincent W.

1994-01-01

A device for bonding a thermoplastic tape to a substrate to form a fully consolidated composite. This device has an endless chain associated with a frame so as to rotate in a plane that is perpendicular to a long dimension of the tape, the chain having pivotally connected chain links with each of the links carrying a flexible foot member that extends outwardly from the chain. A selected number of the foot members contact the tape, after the heating thereof, to cause the heated tape to bond to the substrate. The foot members are each a thin band of metal oriented transversely to the chain, with a flexibility and width and length to contact the tape so as to cause the tape to conform to the substrate to achieve consolidation of the tape and the substrate. A biased leaf-type spring within the frame bears against an inner surface of the chain to provide the compliant pressure necessary to bond the tape to the substrate. The chain is supported by sprockets on shafts rotatably supported in the frame and, in one embodiment, one of the shafts has a drive unit to produce rotation such that the foot members in contact with the tape move at the same speed as the tape. Cooling jets are positioned along the frame to cool the resultant consolidated composite.

Method and apparatus for depositing a coating on a tape carrier

DOEpatents

Storer, Jonathan; Matias, Vladimir

2010-06-15

A system and method for depositing ceramic materials, such as nitrides and oxides, including high temperature superconducting oxides on a tape substrate. The system includes a tape support assembly that comprises a rotatable drum. The rotatable drum supports at least one tape substrate axially disposed on the surface of the drum during the deposition of metals on the tape and subsequent oxidation to form the ceramic materials. The drum is located within a stator having a slot that is axially aligned with the drum. A space exists between the drum and stator. The space is filled with a predetermined partial pressure of a reactive gas. The drum, stator, and space are heated to a predetermined temperature. To form the ceramic material on the tape substrate, the drum is first rotated to align the tape substrate with the slot, and at least one metal is deposited on the substrate. The drum then continues to rotate, bringing the tape substrate into the space, where the metal deposited on the tape substrate reacts with the reactive gas to form the ceramic material. In one embodiment, the tape support system also includes a pay-out/take-up system that co-rotates with the drum and provides a continuous length of tape substrate.

Method of constructing a superconducting magnet

DOEpatents

Satti, John A.

1981-01-01

A superconducting magnet designed to produce magnetic flux densities of the order of 4 to 5 Webers per square meter is constructed by first forming a cable of a plurality of matrixed superconductor wires with each wire of the plurality insulated from each other one. The cable is shaped into a rectangular cross-section and is wound with tape in an open spiral to create cooling channels. Coils are wound in a calculated pattern in saddle shapes to produce desired fields, such as dipoles, quadrupoles, and the like. Wedges are inserted between adjacent cables as needed to maintain substantially radial placement of the long dimensions of cross sections of the cables. After winding, individual strands in each of the cables are brought out to terminals and are interconnected to place all of the strands in series and to maximize the propagation of a quench by alternating conduction from an inner layer to an outer layer and from top half to bottom half as often as possible. Individual layers are separated from others by spiraled aluminum spacers to facilitate cooling. The wound coil is wrapped with an epoxy tape that is cured by heat and then machined to an interference fit with an outer aluminum pipe which is then affixed securely to the assembled coil by heating it to make a shrink fit. In an alternate embodiment, one wire of the cable is made of copper or the like to be heated externally to propagate a quench.

Superconducting magnet

DOEpatents

Satti, John A.

1980-01-01

A superconducting magnet designed to produce magnetic flux densities of the order of 4 to 5 Webers per square meter is constructed by first forming a cable of a plurality of matrixed superconductor wires with each wire of the plurality insulated from each other one. The cable is shaped into a rectangular cross-section and is wound with tape in an open spiral to create cooling channels. Coils are wound in a calculated pattern in saddle shapes to produce desired fields, such as dipoles, quadrupoles, and the like. Wedges are inserted between adjacent cables as needed to maintain substantially radial placement of the long dimensions of cross sections of the cables. After winding, individual strands in each of the cables are brought out to terminals and are interconnected to place all of the strands in series and to maximize the propagation of a quench by alternating conduction from an inner layer to an outer layer and from top half to bottom half as often as possible. Individual layers are separated from others by spiraled aluminum spacers to facilitate cooling. The wound coil is wrapped with an epoxy tape that is cured by heat and then machined to an interference fit with an outer aluminum pipe which is then affixed securely to the assembled coil by heating it to make a shrink fit. In an alternate embodiment, one wire of the cable is made of copper or the like to be heated externally to propagate a quench.

Goddard Space Flight Center specification for Helical-Scan 8-millimeter (mm) magnetic digital data tape cartridge

NASA Technical Reports Server (NTRS)

Perry, Jimmy L.

1992-01-01

The same kind of standard and controls are established that are currently in use for the procurement of new analog, digital, and IBM/IBM compatible 3480 tape cartridges, and 1 in wide channel video magnetic tapes. The Magnetic Tape Certification Facility (MTCF) maintains a Qualified Products List (QPL) for the procurement of new magnetic media and uses the following specifications for the QPL and Acceptance Tests: (1) NASA TM-79724 is used for the QPL and Acceptance Testing of new analog magnetic tapes; (2) NASA TM-80599 is used for the QPL and Acceptance Testing of new digital magnetic tapes; (3) NASA TM-100702 is used for the QPL and Acceptance Testing of new IBM/IBM compatible 3840 magnetic tape cartridges; and (4) NASA TM-100712 is used for the QPL and Acceptance Testing of new 1 in wide channel video magnetic tapes. This document will be used for the QPL and Acceptance Testing of new Helical Scan 8 mm digital data tape cartridges.

Tape Placement Head for Applying Thermoplastic Tape to an Object

NASA Technical Reports Server (NTRS)

Cope, Ralph D. (Inventor); Funck, Steve B. (Inventor); Gruber, Mark B. (Inventor); Lamontia, Mark A. (Inventor); Johnson, Anthony D. (Inventor)

2008-01-01

A tape placement head for applying thermoplastic tape to an object includes a heated feeder which guides the tape/tow to a heated zone. The heated zone has a line compactor having a single row of at least one movable heated member. An area compactor is located in the heated zone downstream from the line compactor. The area compactor includes a plurality of rows of movable feet which are extendable toward the tape/tow different distances with respect to each other to conform to the shape of the object. A shim is located between the heated compactors and the tape/tow. A chilled compactor is in a chilled zone downstream from the heated zone. The chilled zone includes a line chilled compactor and an area chilled compactor. A chilled shim is mounted between the chilled compactor and the tape/tow.

The Ergogenic Effect of Elastic Therapeutic Tape on Stride and Step Length in Fatigued Runners

PubMed Central

Ward, John; Sorrels, Kenneth; Coats, Jesse; Pourmoghaddam, Amir; Moskop, JoAnn; Ueckert, Kate; Glass, Amanda

2014-01-01

Objective The purpose of this study was to determine if elastic therapeutic tape placed on anterior lower limbs would affect stride and step length in fatigued runners’ gait. Methods Forty-two healthy participants were equally divided into a kinesiology tape group (Rocktape) and a no-tape control group. Participants in both groups underwent a baseline running gait test at 6 mph without tape. After this, participants engaged in an exhaustive lower body fatigue protocol until they reached maximal volitional exhaustion. Participants were then randomized to 1 of 2 interventions: (1) Experimental group, which had kinesiology tape placed under tension on the anterior aspect of their lower limbs bilaterally from the upper thigh to just below the patella, or (2) Control group, which did not receive taping. All participants then engaged in a similar 6-mph running gait postanalysis. Participant’s gait was analyzed for 90 seconds during each test iteration. Researchers used a 2-way repeated-measures analysis of variance considering fatigue (prefatigue, postfatigue) and group (tape, no-tape) as subject factors. Results After the fatigue protocol, the no-tape group demonstrated a significant decrease in step length of 14.2 mm (P = .041) and stride length of 29.4 mm (P = .043). The kinesiology tape group did not demonstrate a significant decline in these gait parameters. Conclusions In this preliminary study, placing elastic therapeutic tape over the anterior lower limbs demonstrated short-term preservation of runner step length and stride length in a fatigued state. PMID:25435835

Universality, twisted fans, and the Ising model. [Renormalization, two-loop calculations, scale

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

Dash, J.W.; Harrington, S.J.

1975-06-24

Critical exponents are evaluated for the Ising model using universality in the form of ''twisted fans'' previously introduced in Reggeon field theory. The universality is with respect to scales induced through renormalization. Exact twists are obtained at ..beta.. = 0 in one loop for D = 2,3 with ..nu.. = 0.75 and 0.60 respectively. In two loops one obtains ..nu.. approximately 1.32 and 0.68. No twists are obtained for eta, however. The results for the standard two loop calculations are also presented as functions of a scale.

Twist-3 contributions to wide-angle photoproduction of pions

NASA Astrophysics Data System (ADS)

Kroll, P.; Passek-Kumerički, K.

2018-04-01

We investigate wide-angle π0 photoproduction within the handbag approach to twist-3 accuracy. In contrast to earlier work both the 2-particle as well as the 3-particle twist-3 contributions are taken into account. It is shown that both are needed for consistent results that respect gauge invariance and crossing properties. The numerical studies reveal the dominance of the twist-3 contribution. With it fair agreement with the recent CLAS measurement of the π0 cross section is obtained. We briefly comment also on wide-angle photoproduction of other pseudoscalar mesons.

Moiré edge states in twisted graphene nanoribbons

NASA Astrophysics Data System (ADS)

Fleischmann, M.; Gupta, R.; Weckbecker, D.; Landgraf, W.; Pankratov, O.; Meded, V.; Shallcross, S.

2018-05-01

The edge physics of graphene based systems is well known to be highly sensitive to the atomic structure at the boundary, with localized zero mode edge states found only on the zigzag-type termination of the lattice. Here we demonstrate that the graphene twist bilayer supports an additional class of edge states, that (i) are found for all edge geometries and thus are robust against edge roughness, (ii) occur at energies coinciding with twist induced Van Hove singularities in the bulk and (iii) possess an electron density strongly modulated by the moiré lattice. Interestingly, these "moiré edge states" exist only for certain lattice commensurations and thus the edge physics of the twist bilayer is, in dramatic contrast to that of the bulk, not uniquely determined by the twist angle.

Composite material bend-twist coupling for wind turbine blade applications

NASA Astrophysics Data System (ADS)

Walsh, Justin M.

Current efforts in wind turbine blade design seek to employ bend-twist coupling of composite materials for passive power control by twisting blades to feather. Past efforts in this area of study have proved to be problematic, especially in formulation of the bend-twist coupling coefficient alpha. Kevlar/epoxy, carbon/epoxy and glass/epoxy specimens were manufactured to study bend-twist coupling, from which numerical and analytical models could be verified. Finite element analysis was implemented to evaluate fiber orientation and material property effects on coupling magnitude. An analytical/empirical model was then derived to describe numerical results and serve as a replacement for the commonly used coupling coefficient alpha. Through the results from numerical and analytical models, a foundation for aeroelastic design of wind turbines blades utilizing biased composite materials is provided.

Formation of Twisted Elephant Trunks in the Rosette Nebula

NASA Astrophysics Data System (ADS)

Carlqvist, P.; Gahm, G. F.; Kristen, H.

New observations show that dark elephant trunks in the Rosette nebula are often built up by thin filaments. In several of the trunks the filaments seem to form a twisted pattern. This pattern is hard to reconcile with current theory. We propose a new model for the formation of twisted elephant trunks in which electromagnetic forces play an important role. The model considers the behaviour of a twisted magnetic filament in a molecular cloud, where a cluster of hot stars has been recently born. As a result of stellar winds, and radiation pressure, electromagnetic forces, and inertia forces part of the filament can develop into a double helix pointing towards the stars. The double helix represents the twisted elephant trunk. A simple analogy experiment visualizes and supports the trunk model.

Slug, Twist, and E-Cadherin as Immunohistochemical Biomarkers in Meningeal Tumors

PubMed Central

Nagaishi, Masaya; Nobusawa, Sumihito; Tanaka, Yuko; Ikota, Hayato; Yokoo, Hideaki; Nakazato, Yoichi

2012-01-01

The overexpression of Twist and Slug and subsequent down-regulation of E-cadherin facilitate the acquirement of invasive growth properties in cancer cells. It is unclear which of these molecules are expressed in mesenchymal tumors in the central nervous system. Here, we investigated 10 cases each of hemangiopericytoma, solitary fibrous tumor, meningothelial, fibrous, angiomatous, and atypical meningiomas, and 5 cases of anaplastic meningioma for Slug, Twist, E-cadherin, and N-cadherin immunoexpression. Nuclear Slug expression was observed in 9/10 (90%) hemangiopericytomas and 5/10 (50%) solitary fibrous tumors, but not in any meningiomas, except for 1 case. Similarly, nuclear Twist expression was more extensive in hemangiopericytomas and solitary fibrous tumors than meningiomas. In contrast to Slug and Twist, the positive expression of E-cadherin was observed in 39/45 (87%) meningiomas, but not in any hemangiopericytomas or solitary fibrous tumors (P<0.0001). The fraction of tumor cells expressing E-cadherin in meningeal tumors was negatively correlated to those of Twist (P = 0.004) and Slug (P<0.0001). The overexpression of Slug and Twist with down-regulation of E-cadherin was characteristic findings in hemangiopericytomas and solitary fibrous tumors, but not in meningiomas. The immunohistochemical profiles of the two tumor groups may be useful as diagnostic markers in cases that present a differential diagnosis challenge. PMID:23029385

Full action of two deformation operators in the D1D5 CFT

NASA Astrophysics Data System (ADS)

Carson, Zaq; Hampton, Shaun; Mathur, Samir D.

2017-11-01

We are interested in thermalization in the D1D5 CFT, since this process is expected to be dual to black hole formation. We expect that the lowest order process where thermalization occurs will be at second order in the perturbation that moves us away from the orbifold point. The operator governing the deformation off of the orbifold point consists of a twist operator combined with a supercharge operator acting on this twist. In a previous paper we computed the action of two twist operators on an arbitrary state of the CFT. In the present work we compute the action of the supercharges on these twist operators, thereby obtaining the full action of two deformation operators on an arbitrary state of the CFT. We show that the full amplitude can be related to the amplitude with just the twists through an action of the supercharge operators on the initial and final states. The essential part of this computation consists of moving the contours from the twist operators to the initial and final states; to do this one must first map the amplitude to a covering space where the twists are removed, and then map back to the original space on which the CFT is defined.

Nanorobotic System iTRo for Controllable 1D Micro/nano Material Twisting Test.

PubMed

Lu, Haojian; Shang, Wanfeng; Wei, Xueyong; Yang, Zhan; Fukuda, Toshio; Shen, Yajing

2017-06-08

In-situ micro/nano characterization is an indispensable methodology for material research. However, the precise in-situ SEM twisting of 1D material with large range is still challenge for current techniques, mainly due to the testing device's large size and the misalignment between specimen and the rotation axis. Herein, we propose an in-situ twist test robot (iTRo) to address the above challenges and realize the precise in-situ SEM twisting test for the first time. Firstly, we developed the iTRo and designed a series of control strategies, including assembly error initialization, triple-image alignment (TIA) method for rotation axis alignment, deformation-based contact detection (DCD) method for sample assembly, and switch control for robots cooperation. After that, we chose three typical 1D material, i.e., magnetic microwire Fe 74 B 13 Si 11 C 2 , glass fiber, and human hair, for twisting test and characterized their properties. The results showed that our approach is able to align the sample to the twisting axis accurately, and it can provide large twisting range, heavy load and high controllability. This work fills the blank of current in-situ mechanical characterization methodologies, which is expected to give significant impact in the fundamental nanomaterial research and practical micro/nano characterization.

Electronic structure and optical properties of twisted bilayer graphene calculated via time evolution of states in real space

NASA Astrophysics Data System (ADS)

Le, H. Anh; Do, V. Nam

2018-03-01

We investigate the electronic and optical properties of twisted bilayer graphene with arbitrary twist angles θ . Our results are based on a method of evolving in time quantum states in lattice space. We propose an efficient scheme of sampling lattice nodes that helps to reduce significantly computational cost, particularly for tiny twist angles. We demonstrate the continuous variation of the density of states and the optical conductivity with respect to the twist angle. It indicates that the commensurability between the two graphene layers does not play an essential role in governing the electronic and optical properties. We point out that, for the twist angles roughly in the range 0 .1∘<θ <3∘ , the density of states in the vicinity of the Fermi energy exhibits the typical W shape with a small peak locating at the Fermi energy. This peak is formed as the merging of two van Hove peaks and reflects the appearance of states strongly localized in the AA-like region of moiré zones. When decreasing the twist angle to zero, the W shape is gradually transformed to the U shape, which is seen as the behavior of the density of states in the limit of θ →0∘ .

Five year magnetic tape for unattended satellite tape recorders

NASA Technical Reports Server (NTRS)

Benn, G. S. L.; Gutfreund, K.

1972-01-01

The development and fabrication of a quantity of long life magnetic tape with properties selected specifically for unattended operation in spacecraft tape recorders was studied. A detailed analytical consideration of various binder systems was undertaken. This included the chemical aspects of the binders, cohesion and adhesion effects, stability and the mechanical and physical properties. The ability to form free films of these polymers and their combination with various oxide loadings and other additives allowed a rapid selection of four polymer candidates for a five year magnetic tape. Samples were evaluated under actual running conditions which included physical, magnetic, and extensive life testing. These sample tapes withstood 50,000 bidirectional tape passes under fairly harsh operating conditions.

Generation and physical characteristics of the ERTS MSS system corrected computer compatible tapes

NASA Technical Reports Server (NTRS)

Thomas, V. L.

1973-01-01

The generation and format are discussed of the ERTS system corrected multispectral scanner computer compatible tapes. The discussion includes spacecraft sensors, scene characteristics, data transmission, and conversion of data to computer compatible tapes at the NASA Data Processing Facility. Geometeric and radiometric corrections, tape formats, and the physical characteristics of the tapes are also included.

Magnetic helicity and flux tube dynamics in the solar convection zone: Comparisons between observation and theory

NASA Astrophysics Data System (ADS)

Nandy, Dibyendu

2006-12-01

Magnetic helicity, a conserved topological parameter in ideal MHD systems, conditions close to which are realized in the solar plasma, is intimately connected to the creation and subsequent dynamics of magnetic flux tubes in the solar interior. It can therefore be used as a tool to probe such dynamics. In this paper we show how photospheric observations of magnetic helicity of isolated magnetic flux tubes, manifested as the twist and writhe of solar active regions, can constrain the creation and dynamics of flux tubes in the solar convection zone and the nature of convective turbulence itself. We analyze the observed latitudinal distribution of twists in photospheric active regions, derived from solar vector magnetograms, in the largest such sample studied till-date. We confirm and put additional constraints on the hemispheric twist helicity trend and find that the dispersion in the active region twist distribution is latitude-independent, implying that the amplitude of turbulent fluctuations does not vary with latitude in the convection zone. Our data set also shows that the amplitude and dispersion of twist decreases with increasing magnetic size of active regions, supporting the conclusion that larger flux tubes are less affected by turbulence. Among the various theoretical models that have been proposed till-date to explain the origin of twist, our observations best match the Σ effect model, which invokes helical turbulent buffeting of rising flux tubes as the mechanism for twist creation. Finally, we complement our analysis of twists with past observations of tilts in solar active regions and tie them in with theoretical modeling studies, to build up a comprehensive picture of the dynamics of twisted magnetic flux tubes throughout the solar convection zone. This general framework, binding together theory and observations, suggests that flux tubes have a wide range of twists in the solar convection zone, with some as high as to make them susceptible to the kink instability mechanism that results in the formation of δ spot or non-Hale active regions.

Experiments and FE modeling of stress-strain state in ReBCO tape under tensile, torsional and transverse load

NASA Astrophysics Data System (ADS)

Ilin, K.; Yagotintsev, K. A.; Zhou, C.; Gao, P.; Kosse, J.; Otten, S. J.; Wessel, W. A. J.; Haugan, T. J.; van der Laan, D. C.; Nijhuis, A.

2015-05-01

For high current superconductors in high magnet fields with currents in the order of 50 kA, single ReBCO coated conductors must be assembled in a cable. The geometry of such a cable is mostly such that combined torsion, axial and transverse loading states are anticipated in the tapes and tape joints. The resulting strain distribution, caused by different thermal contraction and electromagnetic forces, will affect the critical current of the tapes. Tape performance when subjected to torsion, tensile and transverse loading is the key to understanding limitations for the composite cable performance. The individual tape material components can be deformed, not only elastically but also plastically under these loads. A set of experimental setups, as well as a convenient and accurate method of stress-strain state modeling based on the finite element method have been developed. Systematic measurements on single ReBCO tapes are carried out combining axial tension and torsion as well as transverse loading. Then the behavior of a single tape subjected to the various applied loads is simulated in the model. This paper presents the results of experimental tests and detailed FE modeling of the 3D stress-strain state in a single ReBCO tape under different loads, taking into account the temperature dependence and the elastic-plastic properties of the tape materials, starting from the initial tape processing conditions during its manufacture up to magnet operating conditions. Furthermore a comparison of the simulations with experiments is presented with special attention for the critical force, the threshold where the tape performance becomes irreversibly degraded. We verified the influence of tape surface profile non-uniformity and copper stabilizer thickness on the critical force. The FE models appear to describe the tape experiments adequately and can thus be used as a solid basis for optimization of various cabling concepts.

Thermoplastic tape compaction device

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

Campbell, V.W.

1994-12-27

A device is disclosed for bonding a thermoplastic tape to a substrate to form a fully consolidated composite. This device has an endless chain associated with a frame so as to rotate in a plane that is perpendicular to a long dimension of the tape, the chain having pivotally connected chain links with each of the links carrying a flexible foot member that extends outwardly from the chain. A selected number of the foot members contact the tape, after the heating thereof, to cause the heated tape to bond to the substrate. The foot members are each a thin bandmore » of metal oriented transversely to the chain, with a flexibility and width and length to contact the tape so as to cause the tape to conform to the substrate to achieve consolidation of the tape and the substrate. A biased leaf-type spring within the frame bears against an inner surface of the chain to provide the compliant pressure necessary to bond the tape to the substrate. The chain is supported by sprockets on shafts rotatably supported in the frame and, in one embodiment, one of the shafts has a drive unit to produce rotation such that the foot members in contact with the tape move at the same speed as the tape. Cooling jets are positioned along the frame to cool the resultant consolidated composite. 5 figures.« less

Thermoplastic tape compaction device

DOEpatents

Campbell, V.W.

1994-12-27

A device is disclosed for bonding a thermoplastic tape to a substrate to form a fully consolidated composite. This device has an endless chain associated with a frame so as to rotate in a plane that is perpendicular to a long dimension of the tape, the chain having pivotally connected chain links with each of the links carrying a flexible foot member that extends outwardly from the chain. A selected number of the foot members contact the tape, after the heating thereof, to cause the heated tape to bond to the substrate. The foot members are each a thin band of metal oriented transversely to the chain, with a flexibility and width and length to contact the tape so as to cause the tape to conform to the substrate to achieve consolidation of the tape and the substrate. A biased leaf-type spring within the frame bears against an inner surface of the chain to provide the compliant pressure necessary to bond the tape to the substrate. The chain is supported by sprockets on shafts rotatably supported in the frame and, in one embodiment, one of the shafts has a drive unit to produce rotation such that the foot members in contact with the tape move at the same speed as the tape. Cooling jets are positioned along the frame to cool the resultant consolidated composite. 5 figures.

Performance of twist-coupled blades on variable speed rotors

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

Lobitz, D.W.; Veers, P.S.; Laino, D.J.

1999-12-07

The load mitigation and energy capture characteristics of twist-coupled HAWT blades that are mounted on a variable speed rotor are investigated in this paper. These blades are designed to twist toward feather as they bend with pretwist set to achieve a desirable twist distribution at rated power. For this investigation, the ADAMS-WT software has been modified to include blade models with bending-twist coupling. Using twist-coupled and uncoupled models, the ADAMS software is exercised for steady wind environments to generate C{sub p} curves at a number of operating speeds to compare the efficiencies of the two models. The ADAMS software ismore » also used to generate the response of a twist-coupled variable speed rotor to a spectrum of stochastic wind time series. This spectrum contains time series with two mean wind speeds at two turbulence levels. Power control is achieved by imposing a reactive torque on the low speed shaft proportional to the RPM squared with the coefficient specified so that the rotor operates at peak efficiency in the linear aerodynamic range, and by limiting the maximum RPM to take advantage of the stall controlled nature of the rotor. Fatigue calculations are done for the generated load histories using a range of material exponents that represent materials from welded steel to aluminum to composites, and results are compared with the damage computed for the rotor without twist-coupling. Results indicate that significant reductions in damage are achieved across the spectrum of applied wind loading without any degradation in power production.« less

A new method of measurement of tension on a moving magnetic tape

NASA Technical Reports Server (NTRS)

Kurtinaytis, A. K.; Lauzhinskas, Y. S.

1973-01-01

The possibility of no-contact measurement of the tension on a moving magnetic tape, assuming the tape is uniform, is discussed. A scheme for calculation of the natural frequency of transverse vibrations of magnetic tape is shown. Mathematical models are developed to show the relationships of the parameters. The method is applicable to the analysis of accurate tape feed mechanisms design.

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

Norsworthy, R.

A rating system was developed for several coating types used for underground pipeline systems. Consideration included soil stress, adhesion, surface preparation, cathodic protection (CP) shielding, CP requirements, handling and construction, repair, field joint system, bends and other components, and the application process. Polyethylene- and polyvinyl chloride-backed tapes, woven polyolefin geotextile fabric (WGF)-backed tapes, hot-applied tapes, petrolatum- and wax-based tapes, and shrink sleeves were evaluated. WGF-backed tapes had the highest rating.

Kinesio taping in young healthy subjects does not affect postural reflex reactions and anticipatory postural adjustments of the trunk: a pilot study.

PubMed

Voglar, Matej; Sarabon, Nejc

2014-09-01

Therapeutic Kinesio Taping method is used for treatment of various musculo-skeletal conditions. Kinesio Taping might have some small clinically important beneficial effects on range of motion and strength but findings about the effects on proprioception and muscle activation are inconsistent. The aim of this study was to test if Kinesio Taping influences anticipatory postural adjustments and postural reflex reactions. To test the hypothesis twelve healthy young participants were recruited in randomized, participants blinded, placebo controlled cross-over study. In the experimental condition the tape was applied over the paravertebral muscles and in placebo condition sham application of the tape was done transversally over the lumbar region. Timing of anticipatory postural adjustments to fast voluntary arms movement and postural reflex reactions to sudden loading over the hands were measured by means of superficial electromyography before and one hour after each tape application. Results showed no significant differences between Kinesio Taping and placebo taping conditions for any of the analyzed muscles in anticipatory postural adaptations (F1,11 < 0.23, p > 0.64, η2 < 0.04) or postural reflex reactions (F1,11 < 4.16, p > 0.07, η(2) < 0.49). Anticipatory postural adjustments of erector spinae and multifidus muscles were initiated significantly earlier after application of taping (regardless of technique) compared to pre-taping (F1,11 = 5.02, p = 0.046, η(2) = 0.31 and F1,11 = 6.18, p = 0.030, η(2) = 0.36 for erector spinae and multifidus, respectively). Taping application over lumbar region has potential beneficial effects on timing of anticipatory postural adjustments regardless of application technique but no effect on postural reflex reactions in young pain free participants. Further research in patients with low back pain would be encouraged. Key PointsApplication of Kinesio Taping does not affect postural reflex reactions in young healthy population.Earlier anticipatory postural adjustments were observed under both Kinesio Taping and placebo conditions.There were no significant differences between Kinesio Taping and placebo condition.

Using 4th order Runge-Kutta method for solving a twisted Skyrme string equation

NASA Astrophysics Data System (ADS)

Hadi, Miftachul; Anderson, Malcolm; Husein, Andri

2016-03-01

We study numerical solution, especially using 4th order Runge-Kutta method, for solving a twisted Skyrme string equation. We find numerically that the value of minimum energy per unit length of vortex solution for a twisted Skyrmion string is 20.37 × 1060 eV/m.

TWIST and p-Akt immunoexpression in normal oral epithelium oral dysplasia and in oral squamous cell carcinoma

PubMed Central

Yamamoto, Fernanda-Paula; Corrêa Pontes, Flávia-Sirotheau; Cury, Sérgio-Elias; Fonseca, Felipe-Paiva; Rebelo-Pontes, Hélder; Pinto-Júnior, Décio-dos Santos

2012-01-01

Objectives: The aim of this study was to evaluate the immunoexpression of TWIST and p-Akt proteins in oral leukoplakia (OL) and oral squamous cell carcinoma (OSCC), correlating their expressions with the histological features of the lesions. Study design: Immunohistochemical studies were carried out on 10 normal oral epithelium, 30 OL and 20 OSCC formalin-fixed, paraffin-embedded tissue samples. Immunoperoxidase reactions for TWIST and p-Akt proteins were applied on the specimens and the positivity of the reactions was calculated for 1000 epithelial cells. Results: Kruskal-Wallis and Dunn’s post tests revealed a significant difference in TWIST and p-Akt immunoexpression among normal oral mucosa, OL and OSCC. In addition, a significant positive correlation was found between TWIST and p-Akt expressions according to the Pearson’s correlation test. Conclusions: The results obtained in the current study suggest that TWIST and p-Akt may participate of the multi-step process of oral carcinogenesis since its early stages. Key words: Oral cancer, oral leukoplakia, dysplasia, immunohistochemistry. PMID:21743395

Torsional mechanics of DNA are regulated by small-molecule intercalation.

PubMed

Celedon, Alfredo; Wirtz, Denis; Sun, Sean

2010-12-23

Whether the bend and twist mechanics of DNA molecules are coupled is unclear. Here, we report the direct measurement of the resistive torque of single DNA molecules to study the effect of ethidium bromide (EtBr) intercalation and pulling force on DNA twist mechanics. DNA molecules were overwound and unwound using recently developed magnetic tweezers where the molecular resistive torque was obtained from Brownian angular fluctuations. The effect of EtBr intercalation on the twist stiffness was found to be significantly different from the effect on the bend persistence length. The twist stiffness of DNA was dramatically reduced at low intercalator concentration (<10 nM); however, it did not decrease further when the intercalator concentration was increased by 3 orders of magnitude. We also determined the dependence of EtBr intercalation on the torque applied to DNA. We propose a model for the elasticity of DNA base pairs with intercalated EtBr molecules to explain the abrupt decrease of twist stiffness at low EtBr concentration. These results indicate that the bend and twist stiffnesses of DNA are independent and can be differently affected by small-molecule binding.

Twist1-positive epithelial cells retain adhesive and proliferative capacity throughout dissemination

PubMed Central

Shamir, Eliah R.; Coutinho, Kester; Georgess, Dan; Auer, Manfred

2016-01-01

ABSTRACT Dissemination is the process by which cells detach and migrate away from a multicellular tissue. The epithelial-to-mesenchymal transition (EMT) conceptualizes dissemination in a stepwise fashion, with downregulation of E-cadherin leading to loss of intercellular junctions, induction of motility, and then escape from the epithelium. This gain of migratory activity is proposed to be mutually exclusive with proliferation. We previously developed a dissemination assay based on inducible expression of the transcription factor Twist1 and here utilize it to characterize the timing and dynamics of intercellular adhesion, proliferation and migration during dissemination. Surprisingly, Twist1+ epithelium displayed extensive intercellular junctions, and Twist1– luminal epithelial cells could still adhere to disseminating Twist1+ cells. Although proteolysis and proliferation were both observed throughout dissemination, neither was absolutely required. Finally, Twist1+ cells exhibited a hybrid migration mode; their morphology and nuclear deformation were characteristic of amoeboid cells, whereas their dynamic protrusive activity, pericellular proteolysis and migration speeds were more typical of mesenchymal cells. Our data reveal that epithelial cells can disseminate while retaining competence to adhere and proliferate. PMID:27402962

DC conductivity of twisted bilayer graphene: Angle-dependent transport properties and effects of disorder

NASA Astrophysics Data System (ADS)

Andelković, M.; Covaci, L.; Peeters, F. M.

2018-03-01

The in-plane dc conductivity of twisted bilayer graphene is calculated using an expansion of the real-space Kubo-Bastin conductivity in terms of Chebyshev polynomials. We investigate within a tight-binding approach the transport properties as a function of rotation angle, applied perpendicular electric field, and vacancy disorder. We find that for high-angle twists, the two layers are effectively decoupled, and the minimum conductivity at the Dirac point corresponds to double the value observed in monolayer graphene. This remains valid even in the presence of vacancies, hinting that chiral symmetry is still preserved. On the contrary, for low twist angles, the conductivity at the Dirac point depends on the twist angle and is not protected in the presence of disorder. Furthermore, for low angles and in the presence of an applied electric field, we find that the chiral boundary states emerging between AB and BA regions contribute to the dc conductivity, despite the appearance of localized states in the AA regions. The results agree qualitatively with recent transport experiments in low-angle twisted bilayer graphene.

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

Kanazawa, Koichi; Pitonyak, Daniel; Koike, Yuji

We investigate the behavior under Lorentz transformations of perturbative coefficient functions in a collinear twist-3 formalism relevant for high-energy observables including transverse polarization of hadrons. We argue that those perturbative coefficient functions can, a priori, acquire quite different yet Lorentz-invariant forms in various frames. This somewhat surprising difference can be traced back to a general dependence of the perturbative coefficient functions on light cone vectors which are introduced by the twist-3 factorization formulas and which are frame-dependent. One can remove this spurious frame dependence by invoking so-called Lorentz invariance relations (LIRs) between twist-3 parton correlation functions. Some of those relationsmore » for twist-3 distribution functions were discussed in the literature before. In this paper we derive the corresponding LIRs for twist-3 fragmentation functions. We explicitly demonstrate that these LIRs remove the light cone vector dependence by considering transverse spin observables in the single-inclusive production of hadrons in lepton-nucleon collisions, ℓN→hX. Furthermore, with the LIRs in hand, we also show that twist-3 observables in general can be written solely in terms of three-parton correlation functions.« less

A quality-of-life-oriented endpoint for comparing therapies.

PubMed

Gelber, R D; Gelman, R S; Goldhirsch, A

1989-09-01

An endpoint, time without symptoms of disease and toxicity of treatment (TWiST), is defined to provide a single measure of length and quality of survival. Time with subjective side effects of treatment and time with unpleasant symptoms of disease are subtracted from overall survival time to calculate TWiST for each patient. The purpose of this paper is to describe the construction of this endpoint, and to elaborate on its interpretation for patient care decision-making. Estimating the distribution of TWiST using actuarial methods is shown by simulation studies to be biased as a result of induced dependency between TWiST and its censoring distribution. Considering the distribution of TWiST accumulated within a specified time from start of therapy, L, allows one to reduce this bias by substituting estimated TWiST for censored values and provides a method to evaluate the "payback" period for early toxic effects. Quantile distance plots provide graphical representations for treatment comparisons. The analysis of Ludwig Trial III evaluating toxic adjuvant therapies versus a no-treatment control group for postmenopausal women with node-positive breast cancer illustrates the methodology.

Far-Infrared and Raman Spectra and The Ring-Twisting Potential Energy Function of 1,3-Cyclohexadiene

NASA Astrophysics Data System (ADS)

Autrey, Daniel; Choo, Jaebum; Laane, Jaan

2001-10-01

The nu19 (A2) ring-twisting vibration of 1,3-cyclohexadiene has been analyzed from the vapor-phase Raman and infrared spectra. The Raman spectrum shows nine ring-twisting transitions in the 116 - 199 cm-1 region. The far-infrared spectrum confirms five of these transitions, despite the fact that the vibration is infrared forbidden in the C2v (planar) approximation. Other Raman and infrared combination bands verify the assignments and provide information on the vibrational coupling. A coordinate dependent kinetic energy expansion for the ring-twisting motion was calculated, and this was used to determine the ring-twisting potential function, which has a barrier to planarity of 1132 cm-1 and energy minima corresponding to twisting angles of 9.1º and 30.1º. Ab initio calculations were also carried out using Moller-Plesset perturbation theory (MP2) with a large number of different basis sets. The various ab initio calculations gave barriers to planarity in the 1197 - 1593 cm-1 range and calculated vibrational frequencies in excellent agreement with the experimental values.

Failure and fatigue characteristics of adhesive athletic tape.

PubMed

Bragg, Richard W; Macmahon, John M; Overom, Erin K; Yerby, Scott A; Matheson, Gordon O; Carter, Dennis R; Andriacchi, Thomas P

2002-03-01

Athletic tape has been commonly reported to lose much of its structural support after 20 min of exercise. Although many studies have addressed the functional performance characteristics of athletic tape, its mechanical properties are poorly understood. This study examines the failure and fatigue properties of several commonly used athletic tapes. A Web-based survey of professional sports trainers was used to select the following three tapes for the study: Zonas (Johnson & Johnson), Leukotape (Beiersdorf), and Jaylastic (Jaybird & Mais). Using a hydraulic material testing system (MTS), eight samples of each tape were compared in three different mechanical tests: load-to-failure, fatigue testing under load control, and fatigue testing under displacement control. Differences in tape microstructure were used to interpret the results of the mechanical tests. Significant differences (P < 0.001) in failure load, elongation at failure, and stiffness were found from failure tests. Significant differences were also found (P < 0.001) in fatigue behavior under both modes of control. As a representative example, in one normalized displacement control fatigue test after 20 min of cycling, 21% (Zonas), 29% (Leukotape), and 57% (Jaylastic) of the mechanical support was lost. After cycling, all tapes loaded to failure showed increased stiffness (P < 0.001), indicating significant energy absorption during cycling. Observed differences in the tapes' microstructure were qualitatively consistent with the measured differences in their mechanical properties. In understanding the shortcomings of currently available tapes, the results of these tests can now be used as benchmarks with which to compare and develop future tape designs. Ultimately, these improved tapes should reduce ankle injuries among athletes.

New collinear twist-3 analysis of transverse SSA: Toward a resolution for the sign-mismatch problem

DOE PAGES

Kanazawa, Koichi; Pitonyak, Daniel; Koike, Yuji; ...

2014-10-19

We present a new collinear twist-3 analysis of the transverse SSA A N at RHIC. We use the TMD Sivers/Collins function to fix some of the relevant collinear twist-3 functions and perform a fit of the RHIC data with other parameterized twist-3 functions. This allows us to keep the consistency among descriptions in pp collision, SIDIS, and e +e – annihilation and thus could provide a unified description of the spin asymmetries in the low- and high-P T processes. In conclusion, by taking into account the twist-3 fragmentation contribution, we show for the first time this contribution could be themore » main source of A N in pp ↑ → hX and its inclusion could provide a solution for the sign-mismatch problem.« less

Scaling effects in resonant coupling phenomena between fundamental and cladding modes in twisted microstructured optical fibers.

PubMed

Napiorkowski, Maciej; Urbanczyk, Waclaw

2018-04-30

We show that in twisted microstructured optical fibers (MOFs) the coupling between the core and cladding modes can be obtained for helix pitch much greater than previously considered. We provide an analytical model describing scaling properties of the twisted MOFs, which relates coupling conditions to dimensionless ratios between the wavelength, the lattice pitch and the helix pitch of the twisted fiber. Furthermore, we verify our model using a rigorous numerical method based on the transformation optics formalism and study its limitations. The obtained results show that for appropriately designed twisted MOFs, distinct, high loss resonance peaks can be obtained in a broad wavelength range already for the fiber with 9 mm helix pitch, thus allowing for fabrication of coupling based devices using a less demanding method involving preform spinning.

Research on resistance characteristics of YBCO tape under short-time DC large current impact

NASA Astrophysics Data System (ADS)

Zhang, Zhifeng; Yang, Jiabin; Qiu, Qingquan; Zhang, Guomin; Lin, Liangzhen

2017-06-01

Research of the resistance characteristics of YBCO tape under short-time DC large current impact is the foundation of the developing DC superconducting fault current limiter (SFCL) for voltage source converter-based high voltage direct current system (VSC-HVDC), which is one of the valid approaches to solve the problems of renewable energy integration. SFCL can limit DC short-circuit and enhance the interrupting capabilities of DC circuit breakers. In this paper, under short-time DC large current impacts, the resistance features of naked tape of YBCO tape are studied to find the resistance - temperature change rule and the maximum impact current. The influence of insulation for the resistance - temperature characteristics of YBCO tape is studied by comparison tests with naked tape and insulating tape in 77 K. The influence of operating temperature on the tape is also studied under subcooled liquid nitrogen condition. For the current impact security of YBCO tape, the critical current degradation and top temperature are analyzed and worked as judgment standards. The testing results is helpful for in developing SFCL in VSC-HVDC.

Effects of kinesio taping and hot packs on premenstrual syndrome in females.

PubMed

Choi, Jung-Hyun

2017-09-01

[Purpose] This study aimed to evaluate the effects of taping and hot packs on premenstrual syndrome, in an attempt to generate basic data for physical therapy intervention for premenstrual syndrome. [Subjects and Methods] Thirty-two females in their 20s with premenstrual syndrome were randomly assigned to a taping group (n=10), hot pack group (n=11), and taping with hot pack group (n=11). Premenstrual syndrome was assessed using the Menstrual Distress Questionnaire in each participant prior to intervention and was re-assessed after applying kinesio taping and/or hot pack from 10 days before the estimated date of menstruation until the first day of menstruation. [Results] Data revealed that the taping and taping with hot pack groups showed significantly reduced premenstrual syndrome following intervention. In terms of the differences in the Menstrual Distress Questionnaire total score among the groups, the taping with hot pack and hot pack groups showed a significant difference. [Conclusion] These findings indicate that kinesio taping is an easy, non-drug intervention for female college students with premenstrual syndrome.

Effects of kinesio taping and hot packs on premenstrual syndrome in females

PubMed Central

Choi, Jung-Hyun

2017-01-01

[Purpose] This study aimed to evaluate the effects of taping and hot packs on premenstrual syndrome, in an attempt to generate basic data for physical therapy intervention for premenstrual syndrome. [Subjects and Methods] Thirty-two females in their 20s with premenstrual syndrome were randomly assigned to a taping group (n=10), hot pack group (n=11), and taping with hot pack group (n=11). Premenstrual syndrome was assessed using the Menstrual Distress Questionnaire in each participant prior to intervention and was re-assessed after applying kinesio taping and/or hot pack from 10 days before the estimated date of menstruation until the first day of menstruation. [Results] Data revealed that the taping and taping with hot pack groups showed significantly reduced premenstrual syndrome following intervention. In terms of the differences in the Menstrual Distress Questionnaire total score among the groups, the taping with hot pack and hot pack groups showed a significant difference. [Conclusion] These findings indicate that kinesio taping is an easy, non-drug intervention for female college students with premenstrual syndrome. PMID:28931978

The influence of vagal control on sex-related differences in left ventricular mechanics and hemodynamics.

PubMed

Williams, Alexandra Mackenzie; Shave, Robert E; Coulson, James M; White, Harriet; Rosser-Stanford, Bryn; Eves, Neil Derek

2018-06-01

Left ventricular (LV) twist mechanics differ between males and females during acute physiological stress, which may be partly mediated by sex differences in autonomic control. While males appear to have greater adrenergic control of LV twist, the potential contribution of vagal modulation to sex differences in LV twist remains unknown. Therefore, this study examined the role of vagal control on sex differences in LV twist during graded lower body negative pressure (LBNP) and supine cycling. On two separate visits, LV mechanics were assessed using 2-dimensional speckle-tracking echocardiography in 18 males (22{plus minus}2yr) and 17 females (21{plus minus}4yr) during -40 and -60 mmHg LBNP and 25% and 50% of peak supine cycling workload, with and without glycopyrrolate (vagal blockade). LV twist was not different at baseline but was greater in females during -60 mmHg in both control (F:16.0{plus minus}3.4º, M:12.9{plus minus}2.3º, p=0.004) and glycopyrrolate trials (F:17.7{plus minus}5.9{degree sign}, M:13.9{plus minus}3.3{degree sign}, p<0.001) due to greater apical rotation during control (F:11.9{plus minus}3.6º, M:7.8{plus minus}1.5º, p<0.001) and glycopyrrolate (F:11.6{plus minus}4.9{degree sign}, M:7.1{plus minus}3.6{degree sign}, p=0.009). These sex differences in LV twist consistently coincided with a greater LV sphericity index (i.e. ellipsoid geometry) in females compared to males. In contrast, LV twist did not differ between the sexes during exercise, with or without glycopyrrolate. Females have augmented LV twist compared to males during large reductions to preload, even during vagal blockade. As such, differences in vagal control do not appear to contribute to sex differences in the LV twist responses to physiological stress, but may be related to differences in ventricular geometry.

Bend-Twist Coupled Carbon-Fiber Laminate Beams: Fundamental Behavior and Applications

NASA Astrophysics Data System (ADS)

Babuska, Pavel

Material-induced bend-twist coupling in laminated composite beams has seen applications in engineered structures for decades, ranging from airplane wings to turbine blades. Symmetric, unbalanced, carbon fiber laminates which exhibit bend-twist coupling can be difficult to characterize and exhibit unintuitive deformation states which may pose challenges to the engineer. In this thesis, bend-twist coupled beams are investigated comprehensively, by experimentation, numerical modeling, and analytical methods. Beams of varying fiber angle and amount of coupling were manufactured and physically tested in both linear and nonlinear static and dynamic settings. Analytical mass and stiffness matrices were derived for the development of a beam element to use in the stiffness matrix analysis method. Additionally, an ABAQUS finite element model was used in conjunction with the analytical methods to predict and further characterize the behavior of the beams. The three regimes, experimental, analytical, and numerical, represent a full-field characterization of bend-twist coupling in composite beams. A notable application of bend-twist coupled composites is for passively adaptive turbine blades whereby the deformation coupling can be built into the blade structure to simultaneously bend and twist, thus pitching the blade into or away from the fluid flow, changing the blade angle of attack. Passive pitch adaptation has been implemented successfully in wind turbine blades, however, for marine turbine blades, the technology is still in the development phase. Bend-twist coupling has been shown numerically to be beneficial to the tidal turbine performance, however little validation has been conducted in the experimental regime. In this thesis, passively adaptive experiment scale tidal turbine blades were designed, analyzed, manufactured, and physically tested, validating the foundational numerical work. It was shown that blade forces and root moments as well as turbine thrust and power coefficients can be manipulated by inclusion of passive pitch adaption by bend-twist coupling.

Stromal Clues in Endometrial Carcinoma: Loss of Expression of β-Catenin, Epithelial-Mesenchymal Transition Regulators, and Estrogen-Progesterone Receptor.

PubMed

Senol, Serkan; Sayar, Ilyas; Ceyran, Ayse B; Ibiloglu, Ibrahim; Akalin, Ibrahim; Firat, Ugur; Kosemetin, Duygu; Engin Zerk, Pinar; Aydin, Abdullah

2016-05-01

Epithelial-stroma interactions in the endometrium are known to be responsible for physiological functions and emergence of several pathologic lesions. Periglandular stromal cells act on endometrial cells in a paracrine manner through sex hormones. In this study, we immunohistochemically evaluated the expression of epithelial-mesenchymal transition regulators (SNAIL/SLUG, TWIST, ZEB1), adhesion molecules (β-catenin and E-cadhenin), estrogen (ER)-progesterone (PR) receptor and their correlation with each other in 30 benign, 148 hyperplastic (EH), and 101 endometrioid-type endometrial carcinoma (EC) endometria. In the epithelial component, loss of expression in E-cadherin, ER and PR, and overexpression of TWIST and ZEB1 were significantly higher in EC than in EH (P<0.01). In the periglandular stromal component, β-catenin and SNAIL/SLUG expression were significantly higher in normal endometrium and simple without atypical EH compared with complex atypical EH and EC (P<0.01). In addition, periglandular stromal TWIST expression was significantly higher in EH group compared with EC (P<0.05). There was significantly negative correlation between β-catenin and ER, TWIST and ER, and TWIST and PR in hyperplastic and carcinomatous glandular epithelium, whereas there was a significantly positive correlation between β-catenin and SNAIL-SLUG, β-catenin and TWIST, β-catenin and ER, β-catenin and PR, SNAIL-SLUG and ER, SNAIL-SLUG and PR, TWIST and ER, TWIST and PR, in periglandular/cancer-associated stromal cells (P<0.01). In conclusion, the pattern of positive and negative correlations in the expression of epithelial-mesenchymal transition regulators (SNAIL-SLUG and TWIST), sex hormone receptors (ER and PR), and β-catenin between ECs and hyperplasia, as well as between epithelium and stroma herein, is suggestive of a significant role for these proteins and their underlying molecular processes in the development of endometrial carcinomas.

Stromal Clues in Endometrial Carcinoma: Loss of Expression of β-Catenin, Epithelial-Mesenchymal Transition Regulators, and Estrogen-Progesterone Receptor

PubMed Central

Sayar, Ilyas; Ceyran, Ayse B.; Ibiloglu, Ibrahim; Akalin, Ibrahim; Firat, Ugur; Kosemetin, Duygu; Engin Zerk, Pinar; Aydin, Abdullah

2016-01-01

Epithelial-stroma interactions in the endometrium are known to be responsible for physiological functions and emergence of several pathologic lesions. Periglandular stromal cells act on endometrial cells in a paracrine manner through sex hormones. In this study, we immunohistochemically evaluated the expression of epithelial-mesenchymal transition regulators (SNAIL/SLUG, TWIST, ZEB1), adhesion molecules (β-catenin and E-cadhenin), estrogen (ER)-progesterone (PR) receptor and their correlation with each other in 30 benign, 148 hyperplastic (EH), and 101 endometrioid-type endometrial carcinoma (EC) endometria. In the epithelial component, loss of expression in E-cadherin, ER and PR, and overexpression of TWIST and ZEB1 were significantly higher in EC than in EH (P<0.01). In the periglandular stromal component, β-catenin and SNAIL/SLUG expression were significantly higher in normal endometrium and simple without atypical EH compared with complex atypical EH and EC (P<0.01). In addition, periglandular stromal TWIST expression was significantly higher in EH group compared with EC (P<0.05). There was significantly negative correlation between β-catenin and ER, TWIST and ER, and TWIST and PR in hyperplastic and carcinomatous glandular epithelium, whereas there was a significantly positive correlation between β-catenin and SNAIL-SLUG, β-catenin and TWIST, β-catenin and ER, β-catenin and PR, SNAIL-SLUG and ER, SNAIL-SLUG and PR, TWIST and ER, TWIST and PR, in periglandular/cancer-associated stromal cells (P<0.01). In conclusion, the pattern of positive and negative correlations in the expression of epithelial-mesenchymal transition regulators (SNAIL-SLUG and TWIST), sex hormone receptors (ER and PR), and β-catenin between ECs and hyperplasia, as well as between epithelium and stroma herein, is suggestive of a significant role for these proteins and their underlying molecular processes in the development of endometrial carcinomas. PMID:26367784

High-order orbital angular momentum mode generator based on twisted photonic crystal fiber.

PubMed

Fu, Cailing; Liu, Shen; Wang, Ying; Bai, Zhiyong; He, Jun; Liao, Changrui; Zhang, Yan; Zhang, Feng; Yu, Bin; Gao, Shecheng; Li, Zhaohui; Wang, Yiping

2018-04-15

High-order orbital angular momentum (OAM) modes, namely, OAM +5 and OAM +6 , were generated and demonstrated experimentally by twisting a solid-core hexagonal photonic crystal fiber (PCF) during hydrogen-oxygen flame heating. Leaky orbital resonances in the cladding depend strongly on the twist rate and length of the helical PCF. Moreover, the generated high-order OAM mode could be a polarized mode. The secret of the successful observation of high-order modes is that leaky orbital resonances in the twisted PCF cladding have a high coupling efficiency of more than -20  dB.

Trapping of ultracold polar molecules with a thin-wire electrostatic trap.

PubMed

Kleinert, J; Haimberger, C; Zabawa, P J; Bigelow, N P

2007-10-05

We describe the realization of a dc electric-field trap for ultracold polar molecules, the thin-wire electrostatic trap (TWIST). The thin wires that form the electrodes of the TWIST allow us to superimpose the trap onto a magneto-optical trap (MOT). In our experiment, ultracold polar NaCs molecules in their electronic ground state are created in the MOT via photoassociation, achieving a continuous accumulation in the TWIST of molecules in low-field seeking states. Initial measurements show that the TWIST trap lifetime is limited only by the background pressure in the chamber.

Origin of chiral interactions in cellulose supra-molecular microfibrils.

PubMed

Khandelwal, Mudrika; Windle, Alan

2014-06-15

The formation of a chiral-nematic phase from cellulose nanowhiskers has been frequently reported in the literature. The most popular theory used to explain the chiral interactions is that of twisted morphology of cellulose nanowhiskers. Two possible origins of twist have been suggested: the intrinsic chirality of cellulose chains and result of interaction of chiral surfaces. High resolution SEM and AFM have been used to locate twists in cellulose microfibrils and nanowhiskers. The origin of the twisted morphology in cellulose microfibrils has been studied with reference to the protein aggregation theory. Copyright © 2014 Elsevier Ltd. All rights reserved.

Twirling and Whirling: Viscous Dynamics of Rotating Elastica

NASA Astrophysics Data System (ADS)

Powers, Thomas R.; Wolgemuth, Charles W.; Goldstein, Raymond E.

1999-11-01

Motivated by diverse phenomena in cellular biophysics, including bacterial flagellar motion and DNA transcription and replication, we study the overdamped nonlinear dynamics of a rotationally forced filament with twist and bend elasticity. The competition between twist diffusion and writhing instabilities is described by a novel pair of coupled PDEs for twist and bend evolution. Analytical and numerical methods elucidate the twist-bend coupling and reveal two dynamical regimes separated by a Hopf bifurcation: (i) diffusion-dominated axial rotation, or twirling, and (ii) steady-state crankshafting motion, or whirling. The consequences of these phenomena for self-propulsion are investigated, and experimental tests proposed.

Generation and physical characteristics of the LANDSAT-1, -2 and -3 MSS computer compatible tapes

NASA Technical Reports Server (NTRS)

Thomas, V. L.

1977-01-01

The generation and format of the LANDSAT 1, 2, and 3 system corrected multispectral scanner computer compatible tapes are discussed. Included in the discussion are the spacecraft sensors, scene characteristics, the transmission of data, and the conversion of the data to computer compatible tapes. Also included in the discussion are geometric and radiometric corrections, tape formats, and the physical characteristics of the tape.

EROS to universal tape conversion processor

NASA Technical Reports Server (NTRS)

Obrien, S. O. (Principal Investigator)

1980-01-01

The function of the EROS processor is to allow a user to select a specific area from a full frame LANDSAT image which is written on tape in the EROS format. The area of interest is read from the EROS formatted tape and converted to the JSC Universal format and written onto another tape. This tape can then be read by the IMDACS processing system and normal analysis can be performed.

Generation and physical characteristics of the Landsat 1 and 2 MSS computer compatible tapes

NASA Technical Reports Server (NTRS)

Thomas, V. L.

1975-01-01

The generation and format is discussed of the Landsat 1 and 2 system corrected multispectral scanner computer compatible tapes. Included in the discussion are the spacecraft sensors, scene characteristics, the transmission of data, and the conversion of the data to computer compatible tapes at the NASA Data Processing Facility. Geometric and radiometric corrections, tape formats, and the physical characteristics of the tape are also described.

Magnetic tape user guide

NASA Technical Reports Server (NTRS)

Evans, A. B.; Lee, L. L.

1985-01-01

This User Guide provides a general introduction to the structure, use, and handling of magnetic tapes at Langley Research Center (LaRC). The topics covered are tape terminology, physical characteristics, error prevention and detection, and creating, using, and maintaining tapes. Supplementary documentation is referenced where it might be helpful. The documentation is included for the tape utility programs, BLOCK, UNBLOCK, and TAPEDMP, which are available at the Central Scientific Computing Complex at LaRC.

Integration of altitude and airspeed information into a primary flight display via moving-tape formats

NASA Technical Reports Server (NTRS)

Abbott, Terence S.; Steinmetz, George G.

1987-01-01

A ground-based aircraft simulation study was conducted to determine the effect on pilot performance of replacing the electromechanical altimeter and airspeed indicators with electronically generated representations integrated into the primary flight display via moving-tape (linear moving scale) formats. Several key factors relating to moving-tape formats were examined during the study: tape centering, secondary (trend) information, and tape orientation. The factor of centering refers to whether the tape was centered about the actual airspeed or altitude or about some defined reference value. Tape orientation refers to whether the values represented are arranged in either descending or ascending order. Six pilots participated in this study, with each subject performing 18 runs along a single, known flight profile. Subjective results indicated that the moving-tape formats were generally better than that of the conventional instruments. They also indicated that an actual-centered fixed pointer was preferred to a reference-centered pointer. Performance data for a visual secondary task showed that formats not containing trend information produced better performance; however, no difference was noted in airspeed tracking or altitude tracking performance. Regarding tape orientation, subjective comments indicated that there was lower work load and better performance when the airspeed tape had the high numbers at the top.

Unraveling the sequence-dependent polymorphic behavior of d(CpG) steps in B-DNA.

PubMed

Dans, Pablo Daniel; Faustino, Ignacio; Battistini, Federica; Zakrzewska, Krystyna; Lavery, Richard; Orozco, Modesto

2014-10-01

We have made a detailed study of one of the most surprising sources of polymorphism in B-DNA: the high twist/low twist (HT/LT) conformational change in the d(CpG) base pair step. Using extensive computations, complemented with database analysis, we were able to characterize the twist polymorphism in the d(CpG) step in all the possible tetranucleotide environment. We found that twist polymorphism is coupled with BI/BII transitions, and, quite surprisingly, with slide polymorphism in the neighboring step. Unexpectedly, the penetration of cations into the minor groove of the d(CpG) step seems to be the key element in promoting twist transitions. The tetranucleotide environment also plays an important role in the sequence-dependent d(CpG) polymorphism. In this connection, we have detected a previously unexplored intramolecular C-H···O hydrogen bond interaction that stabilizes the low twist state when 3'-purines flank the d(CpG) step. This work explains a coupled mechanism involving several apparently uncorrelated conformational transitions that has only been partially inferred by earlier experimental or theoretical studies. Our results provide a complete description of twist polymorphism in d(CpG) steps and a detailed picture of the molecular choreography associated with this conformational change. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

Twist-induced Magnetosphere Reconfiguration for Intermittent Pulsars

NASA Astrophysics Data System (ADS)

Huang, Lei; Yu, Cong; Tong, Hao

2016-08-01

We propose that the magnetosphere reconfiguration induced by magnetic twists in the closed field line region can account for the mode switching of intermittent pulsars. We carefully investigate the properties of axisymmetric force-free pulsar magnetospheres with magnetic twists in closed field line regions around the polar caps. The magnetosphere with twisted closed lines leads to enhanced spin-down rates. The enhancement in spin-down rate depends on the size of the region with twisted closed lines. Typically, it is increased by a factor of ˜2, which is consistent with the intermittent pulsars’ spin-down behavior during the “off” and “on” states. We find that there is a threshold of maximal twist angle {{Δ }}{φ }{{thres}}˜ 1. The magnetosphere is stable only if the closed line twist angle is less than {{Δ }}{φ }{{thres}}. Beyond this value, the magnetosphere becomes unstable and gets untwisted. The spin-down rate would reduce to its off-state value. The quasi-periodicity in spin-down rate change can be explained by long-term activities in the star’s crust and the untwisting induced by MHD instability. The estimated duration of on-state is about 1 week, consistent with observations. Due to the MHD instability, there exists an upper limit for the spin-down ratio (f˜ 3) between the on-state and the off-state, if the Y-point remains at the light cylinder.

Twisting short dsDNA with applied tension

NASA Astrophysics Data System (ADS)

Zoli, Marco

2018-02-01

The twisting deformation of mechanically stretched DNA molecules is studied by a coarse grained Hamiltonian model incorporating the fundamental interactions that stabilize the double helix and accounting for the radial and angular base pair fluctuations. The latter are all the more important at short length scales in which DNA fragments maintain an intrinsic flexibility. The presented computational method simulates a broad ensemble of possible molecule conformations characterized by a specific average twist and determines the energetically most convenient helical twist by free energy minimization. As this is done for any external load, the method yields the characteristic twist-stretch profile of the molecule and also computes the changes in the macroscopic helix parameters i.e. average diameter and rise distance. It is predicted that short molecules under stretching should first over-twist and then untwist by increasing the external load. Moreover, applying a constant load and simulating a torsional strain which over-twists the helix, it is found that the average helix diameter shrinks while the molecule elongates, in agreement with the experimental trend observed in kilo-base long sequences. The quantitative relation between percent relative elongation and superhelical density at fixed load is derived. The proposed theoretical model and computational method offer a general approach to characterize specific DNA fragments and predict their macroscopic elastic response as a function of the effective potential parameters of the mesoscopic Hamiltonian.

Effect of the cross sectional aspect ratio on the flow past a twisted cylinder

NASA Astrophysics Data System (ADS)

Jung, Jae Hwan; Yoon, Hyun Sik

2013-11-01

The cross-flow around twisted cylinders of cross sectional aspect ratio (A/B) from 1 to 2.25 is investigated at a subcritical Reynolds number (Re) of 3000 using large eddy simulation (LES). The flow past a corresponding smooth and wavy cylinder is also calculated for comparison and validation against experimental data. The effect of twisted surface assessed in terms of the mean drag and root-mean-square (RMS) value of fluctuating lift. The shear layer of the twisted cylinder covering the recirculation region is more elongated than those of the smooth and the wavy cylinder. Successively, vortex shedding of the twisted cylinder is considerably suppressed, compared with those of the smooth and the wavy cylinder. The maximum drag reduction of up to 13% compared with a smooth cylinder is obtained at a certain cross sectional aspect ratio. The fluctuating lift coefficient of the twisted cylinder is also significantly suppressed. We found that the cross sectional cross sectional aspect ratio (A/B) plays an essential role in determining the vortical structures behind the twisted cylinder which has a significant effect on the reduction of the fluctuating lift and suppression of flow-induced vibration. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) through GCRC-SOP (No. 2011-0030013).

Acute corneal hydrops mimicking full thickness perforation.

PubMed

Ch'ng, S W; Pillai, M B; Aazeem, S; Tu, K L

2012-05-11

A 26-year-old Caucasian female with keratoconus presented with an acutely painful and red left eye. Visual acuity on presentation was 3/60. Slit lamp examination revealed localised Descemet's membrane break with iris partially plugging it. There was a bulging stromal cyst which would intermittently flatten and reform. The appearance when the cyst was flattened mimicked a full thickness corneal perforation. However, no obvious overlying epithelial defect was detected and an intermittent leakage through micro-perforations in the corneal epithelium was the probable cause of the variable appearance. The anterior chamber reformed and iris plug freed following an insertion of a bandage contact lens and taped eyelid. On follow-up, the Descement's membrane had healed with visual acuity improving to 6/18. Our case illustrates the importance of identifying corneal hydrops mimicking a full thickness perforation as conservative management has a greater chance of recovery.

Adjustable high emittance gap filler. [reentry shielding for space shuttle vehicles

NASA Technical Reports Server (NTRS)

Leiser, D. B.; Stewart, D. A.; Smith, M.; Estrella, C. A.; Goldstein, H. E. (Inventor)

1981-01-01

A flexible, adjustable refractory filler is disclosed for filling gaps between ceramic tiles forming the heat shield of a space shuttle vehicle, to protect its aluminum skin during atmospheric reentry. The easily installed and replaced filler consists essentially of a strip of ceramic cloth coated, at least along both its longitudinal edges with a room temperature vulcanizable silicone rubber compound with a high emittance colored pigment. The filler may have one or more layers as the gap width requires. Preferred materials are basket weave aluminoborosilicate cloth, and a rubber compounded with silicon tetraboride as the emittance agent and finely divided borosilicate glass containing about 7.5% B2O3 as high temperature binder. The filler cloth strip or tape is cut to proper width and length, inserted into the gap, and fastened with previously applied drops of silicone rubber adhesive.

Tools for applying lead tape to flat conductor cabling for chemical stripping

NASA Technical Reports Server (NTRS)

Angele, W.

1969-01-01

Two tools facilitate chemical stripping of insulation on flat conductor cabling. A tape pressing tool and a taping fixture apply adhesive lead tape with the proper amount of pressure to protect the remaining insulation from the chemical stripping solution.

Compilation of fatigue, fatigue-crack propagation, and fracture data for 2024 and 7075 aluminum, Ti-6Al-4V titanium, and 300M steel. Volume 1: Description of data and data storage on magnetic tape. Volume 2: Data tape (7-track magnetic tape)

NASA Technical Reports Server (NTRS)

Rice, R. C.; Reynolds, J. L.

1976-01-01

Fatigue, fatigue-crack-propagation, and fracture data compiled and stored on magnetic tape are documented. Data for 202 and 7075 aluminum alloys, Ti-6Al-4V titanium alloy, and 300M steel are included in the compilation. Approximately 4,500 fatigue, 6,500 fatigue-crack-propagation, and 1,500 fracture data points are stored on magnetic tape. Descriptions of the data, an index to the data on the magnetic tape, information on data storage format on the tape, a listing of all data source references, and abstracts of other pertinent test information from each data source reference are included.

Effects of Corrective Taping on Balance and Gait in Patients With Hallux Valgus.

PubMed

Gur, Gozde; Ozkal, Ozden; Dilek, Burcu; Aksoy, Songul; Bek, Nilgun; Yakut, Yavuz

2017-05-01

Taping is an effective temporary therapy for improving hallux valgus (HV) in adults. Although HV has been demonstrated to impair postural balance, there is a lack of information about how corrective taping affects balance and gait patterns in adults with HV deformity. Eighteen middle-aged female patients (average age, 53.5 years) with HV were included. Corrective tape was applied to correct HV angulation. A series of balance and gait stability tests were performed before applying tape and 1 hour after the tape was applied with a Balance Master computerized posturography device. The study involved the following tests: modified clinical test of sensory interaction and balance (mCTSIB), unilateral stance (US), limit of stability (LoS), step up/over (SUO), and walk across (WA) tests. No significant difference was found between the no-tape and taped condition in the static balance mCTSIB and US tests ( P > .05). The taping intervention resulted in significant improvement in the dynamic balance measures for the LoS test's backward reaction time and left maximum excursion ( P < .05), a significantly higher impact index bilaterally in the SUO assessment ( P < .05), and an increase in step width mean and variability in the WA test ( P < .05). Taping for correcting HV angulation had negative acute effects on dynamic balance in the SUO and WA tests and positive effects in the LoS test. Corrective taping, although a form of conservative treatment for hallux valgus, has been insufficiently studied in terms of effects on balance. Our results show that taping, as an acute effect, may impair balance in middle-aged adults when walking or ascending and descending stairs.

Editing of EIA coded, numerically controlled, machine tool tapes

NASA Technical Reports Server (NTRS)

Weiner, J. M.

1975-01-01

Editing of numerically controlled (N/C) machine tool tapes (8-level paper tape) using an interactive graphic display processor is described. A rapid technique required for correcting production errors in N/C tapes was developed using the interactive text editor on the IMLAC PDS-ID graphic display system and two special programs resident on disk. The correction technique and special programs for processing N/C tapes coded to EIA specifications are discussed.

Combination Therapy with a Second-Generation Androgen Receptor Antagonist and a Metastasis Vaccine Improves Survival in a Spontaneous Prostate Cancer Model

PubMed Central

Ardiani, Andressa; Farsaci, Benedetto; Rogers, Connie J.; Protter, Andy; Guo, Zhimin; King, Thomas H.; Apelian, David; Hodge, James W.

2013-01-01

Purpose Enzalutamide, a second-generation androgen antagonist, was approved by the FDA for castration-resistant prostate cancer (CRPC) treatment. Immunotherapy has been shown to be a promising strategy for prostate cancer. This study is performed to provide data to support the combination of enzalutamide and immunotherapy for CRPC treatment. Experimental Design Male C57BL/6 or TRAMP prostate cancer model mice were exposed to enzalutamide and/or a therapeutic vaccine targeting Twist, an antigen involved in epithelial-to-mesenchymal transition and metastasis. The physiological and immunological effects of enzalutamide were characterized. The generation of Twist-specific immunity by Twist-vaccine was evaluated. Finally, the combination of enzalutamide and Twist-vaccine to improve TRAMP mice overall survival was evaluated. Results Enzalutamide mediated immunogenic modulation in TRAMP-C2 cells. In vivo, enzalutamide mediated reduced genitourinary tissue weight, enlargement of the thymus, and increased levels of T-cell excision circles. Because no changes were seen in T-cell function, as determined by CD4+ T-cell proliferation and Treg functional assays, enzalutamide was determined to be immune inert. Enzalutamide did not diminish the Twist-vaccine’s ability to generate Twist-specific immunity. Twist was confirmed as a valid tumor antigen in TRAMP mice by immunohistochemistry. The combination of enzalutamide and Twist-vaccine resulted in significantly increased overall survival of TRAMP mice compared to other treatment groups (27.5 vs. 10.3 weeks). Notably, the effectiveness of the combination therapy increased with disease stage, i.e., the greatest survival benefit was seen in mice with advanced-stage prostate tumors. Conclusions These data support the combination of enzalutamide and immunotherapy as a promising treatment strategy for CRPC. PMID:24048332

Exact special twist method for quantum Monte Carlo simulations

NASA Astrophysics Data System (ADS)

Dagrada, Mario; Karakuzu, Seher; Vildosola, Verónica Laura; Casula, Michele; Sorella, Sandro

2016-12-01

We present a systematic investigation of the special twist method introduced by Rajagopal et al. [Phys. Rev. B 51, 10591 (1995), 10.1103/PhysRevB.51.10591] for reducing finite-size effects in correlated calculations of periodic extended systems with Coulomb interactions and Fermi statistics. We propose a procedure for finding special twist values which, at variance with previous applications of this method, reproduce the energy of the mean-field infinite-size limit solution within an adjustable (arbitrarily small) numerical error. This choice of the special twist is shown to be the most accurate single-twist solution for curing one-body finite-size effects in correlated calculations. For these reasons we dubbed our procedure "exact special twist" (EST). EST only needs a fully converged independent-particles or mean-field calculation within the primitive cell and a simple fit to find the special twist along a specific direction in the Brillouin zone. We first assess the performances of EST in a simple correlated model such as the three-dimensional electron gas. Afterwards, we test its efficiency within ab initio quantum Monte Carlo simulations of metallic elements of increasing complexity. We show that EST displays an overall good performance in reducing finite-size errors comparable to the widely used twist average technique but at a much lower computational cost since it involves the evaluation of just one wave function. We also demonstrate that the EST method shows similar performances in the calculation of correlation functions, such as the ionic forces for structural relaxation and the pair radial distribution function in liquid hydrogen. Our conclusions point to the usefulness of EST for correlated supercell calculations; our method will be particularly relevant when the physical problem under consideration requires large periodic cells.

PARTIAL ERUPTION OF A FILAMENT WITH TWISTING NON-UNIFORM FIELDS

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

Bi, Yi; Jiang, Yunchun; Yang, Jiayan

The eruption of a filament in a kinklike fashion is often regarded as a signature of kink instability. However, the kink instability threshold for the filament’s magnetic structure is not widely understood. Using Hα observations from the New Vacuum Solar Telescope, we present a partial eruptive filament. During the eruption, the filament thread appeared to split from its middle and to break out in a kinklike fashion. In this period, the remaining filament material stayed below and erupted without the kinking motion later on. The coronal magnetic field lines associated with the filament are obtained from nonlinear force-free field extrapolationsmore » using the twelve-minute-cadence vector magnetograms of the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamic Observatory. We studied the extrapolated field lines passing through the magnetic dips which are in good agreement with the observed filament. The field lines are non-uniformly twisted and appear to be composed of two twisted flux ropes winding around each other. One of them has a higher twist than the other, and the flux rope with the higher twist has its dips aligned with the kinking eruptive thread at the beginning of its eruption. Before the eruption, moreover, the flux rope with the higher twist was found to expand with an approximately constant field twist. In addition, the helicity flux maps deduced from the HMI magnetograms show that some helicity is injected into the overlying magnetic arcade, but no significant helicity is injected into the flux ropes. Accordingly, we suggest that the highly twisted flux rope became kink unstable when the instability threshold declined with the expansion of the flux rope.« less

Recombinant mouse periostin ameliorates coronal sutures fusion in Twist1+/- mice.

PubMed

Bai, Shanshan; Li, Dong; Xu, Liang; Duan, Huichuan; Yuan, Jie; Wei, Min

2018-04-17

Saethre-Chotzen syndrome is an autosomal dominantly inherited disorder caused by mutations in the twist family basic helix-loop-helix transcription factor 1 (TWIST1) gene. Surgical procedures are frequently required to reduce morphological and functional defects in patients with Saethre-Chotzen syndrome. Therefore, the development of noninvasive procedures to treat Saethre-Chotzen syndrome is critical. We identified that periostin, which is an extracellular matrix protein that plays an important role in both bone and connective tissues, is downregulated in craniosynostosis patients. We aimed to verify the effects of different concentrations (0, 50, 100, and 200 μg/l) of recombinant mouse periostin in Twist1 +/- mice (a mouse model of Saethre-Chotzen syndrome) coronal suture cells in vitro and in vivo. Cell proliferation, migration, and osteogenic differentiation were observed and detected. Twist1 +/- mice were also injected with recombinant mouse periostin to verify the treatment effects. Cell Counting Kit-8 results showed that recombinant mouse periostin inhibited the proliferation of suture-derived cells in a time- and concentration-dependent manner. Cell migration was also suppressed when treated with recombinant mouse periostin. Real-time quantitative PCR and Western blotting results suggested that messenger ribonucleic acid and protein expression of alkaline phosphatase, bone sialoprotein, collagen type I, and osteocalcin were all downregulated after treatment with recombinant mouse periostin. However, the expression of Wnt-3a, Wnt-1, and β-catenin were upregulated. The in vivo results demonstrated that periostin-treated Twist1 +/- mice showed patent coronal sutures in comparison with non-treated Twist1 +/- mice which have coronal craniosynostosis. Our results suggest that recombinant mouse periostin can inhibit coronal suture cell proliferation and migration and suppress osteogenic differentiation of suture-derived cells via Wnt canonical signaling, as well as ameliorate coronal suture fusion in Twist1 +/- mice.

Development and evaluation of TWIST Dixon for dynamic contrast-enhanced (DCE) MRI with improved acquisition efficiency and fat suppression.

PubMed

Le, Yuan; Kroeker, Randall; Kipfer, Hal D; Lin, Chen

2012-08-01

To develop a new pulse sequence called time-resolved angiography with stochastic trajectories (TWIST) Dixon for dynamic contrast enhanced magnetic resonance imaging (DCE-MRI). The method combines dual-echo Dixon to generate separated water and fat images with a k-space view-sharing scheme developed for 3D TWIST. The performance of TWIST Dixon was compared with a volume interpolated breathhold examination (VIBE) sequence paired with spectrally selective adiabatic inversion Recovery (SPAIR) and quick fat-sat (QFS) fat-suppression techniques at 3.0T using quantitative measurements of fat-suppression accuracy and signal-to-noise ratio (SNR) efficiency, as well as qualitative breast image evaluations. The water fraction of a uniform phantom was calculated from the following images: 0.66 ± 0.03 for TWIST Dixon; 0.56 ± 0.23 for VIBE-SPAIR, and 0.53 ± 0.14 for VIBE-QFS, while the reference value is 0.70 measured by spectroscopy. For phantoms with contrast (Gd-BOPTA) concentration ranging from 0-6 mM, TWIST Dixon also provides consistently higher SNR efficiency (3.2-18.9) compared with VIBE-SPAIR (2.8-16.8) and VIBE-QFS (2.4-12.5). Breast images acquired with TWIST Dixon at 3.0T show more robust and uniform fat suppression and superior overall image quality compared with VIBE-SPAIR. The results from phantom and volunteer evaluation suggest that TWIST Dixon outperforms conventional methods in almost every aspect and it is a promising method for DCE-MRI and contrast-enhanced perfusion MRI, especially at higher field strength where fat suppression is challenging. Copyright © 2012 Wiley Periodicals, Inc.

Effect of Tape Burnishing and Drive Use on Head Wear in Rotary Tape Drives

NASA Astrophysics Data System (ADS)

Bhushan, Bharat; Anderson, Reid M.; Koinkar, Vilas N.

Three types of 12.7-mm wide metal particle tapes were studied. One of the tapes was calendered, whereas the other two tapes were additionally burnished one or two times using a proprietary process. Each type of tape was studied after 100 passes in the BetaCam SP drive and also in the virgin (0 pass) state. It was reported that in the case of the unburnished tape, head wear was high in the first pass and decreased during use. However, head wear for the double burnished tape was low for the first pass and increased during use. Whereas in the single burnished tape, head wear was low in the first pass and remained low. The objective of this study is to understand the mechanisms for loss and growth of head wear by correlating the surface characteristics of the tapes to head wear rate and to determine the changes in the surface characteristics occurring from 0 to 100 passes in the drive. It was found that summit density, mean and rms summit height, and mean and rms summit curvature correlate well to the head wear data. During manufacture and use in the drive, as the summit density, mean and rms summit height, and mean and rms summit curvature decrease, the head wear rate decreases. The mechanism for head wear is the initial ploughing of dense, sharp and high tape asperities into the surface of the head material resulting in a high head wear rate and a high coefficient of friction. Double burnishing during manufacturing removes high asperities, thus making the tape very smooth and possibly results in high adhesion and head wear growth with use. Chemical changes of the tape surface during double burnishing (not part of this study) also may be responsible for head wear growth during use.

The Repack Challenge

NASA Astrophysics Data System (ADS)

Kruse, Daniele Francesco

2014-06-01

Physics data stored in CERN tapes is quickly reaching the 100 PB milestone. Tape is an ever-changing technology that is still following Moore's law in terms of capacity. This means we can store every year more and more data in the same amount of tapes. However this doesn't come for free: the first obvious cost is the new higher capacity media. The second less known cost is related to moving the data from the old tapes to the new ones. This activity is what we call repack. Repack is vital for any large tape user: without it, one would have to buy more tape libraries and more floor space and, eventually, data on old non supported tapes would become unreadable and be lost forever. In this paper we describe the challenge of repacking 115 PB before LHC data taking starts in the beginning of 2015. This process will have to run concurrently with the existing experiment tape activities, and therefore needs to be as transparent as possible for users. Making sure that this works out seamlessly implies careful planning of the resources and the various policies for sharing them fairly and conveniently. To tackle this problem we need to fully exploit the speed and throughput of our modern tape drives. This involves proper dimensioning and configuration of the disk arrays and all the links between them and the tape servers, i.e the machines responsible for managing the tape drives. It is also equally important to provide tools to improve the efficiency with which we use our tape libraries. The new repack setup we deployed has on average increased tape drive throughput by 80%, allowing them to perform closer to their design specifications. This improvement in turn means a 48% decrease in the number of drives needed to achieve the required throughput to complete the full repack on time.

AdS/CFT, Black Holes, And Fuzzballs

NASA Astrophysics Data System (ADS)

Zadeh, Ida G.

In this thesis we investigate two different aspects of the AdS/CFT correspondence. We first investigate the holographic AdS/CMT correspondence. Gravitational backgrounds in d + 2 dimensions have been proposed as holographic duals to Lifshitz-like theories describing critical phenomena in d + 1 dimensions with critical exponent z ≥ 1. We numerically explore a dilaton-Einstein-Maxwell model admitting such backgrounds as solutions. We show how to embed these solutions into AdS space for a range of values of z and d. We next investigate the AdS3/CFT2 correspondence and focus on the microscopic CFT description of the D1--D5 system on T4 x S1. In the context of the fuzzball programme, we investigate deforming the CFT away from the orbifold point and study lifting of the low-lying string states. We start by considering general 2D orbifold CFTs of the form M N/SN, with M a target space manifold and SN the symmetric group. The Lunin-Mathur covering space technique provides a way to compute correlators in these orbifold theories, and we generalize this technique in two ways. First, we consider excitations of twist operators by modes of fields that are not twisted by that operator, and show how to account for these excitations when computing correlation functions in the covering space. Second, we consider non-twist sector operators and show how to include the effects of these insertions in the covering space. Using the generalization of the Lunin-Mathur symmetric orbifold technology and conformal perturbation theory, we initiate a program to compute the anomalous dimensions of low-lying string states in the D1--D5 superconformal field theory. Our method entails finding four-point functions involving a string operator O of interest and the deformation operator, taking coincidence limits to identify which other operators mix with O, subtracting conformal families of these operators, and computing their mixing coefficients. We find evidence of operator mixing at first order in the deformation parameter, which means that the string state acquires an anomalous dimension. After diagonalization this will mean that anomalous dimensions of some string states in the D1--D5 SCFT must decrease away from the orbifold point while others increase. Finally, we summarize our results and discuss some future directions of research.

Tape reading fixture

NASA Technical Reports Server (NTRS)

1969-01-01

Commercially available roller type desk pad provides an efficient and orderly manner of handling rolled paper tapes for proofreading. The fixture, which is modified to accept Flex-O-Writer or similar tapes and roll them in either direction, reduces the chance of damaging or soiling the tapes through repeated handling.

Micro-Teaching Tapes in Anatomy and Physiology.

ERIC Educational Resources Information Center

Stencel, John E.

1981-01-01

Outlines the development and use of micro-teaching tapes as a means of supplemental instruction for college anatomy and physiology classes. Tapes include brief explanations of difficult concepts taken from lectures as students listen to cassette tapes and fill in blanks, or answer questions. (DS)

Burnout Test of First- and Second-Generation HTS Tapes in Liquid-Nitrogen Bath Cooling

NASA Astrophysics Data System (ADS)

Young, M. A.; Demko, J. A.; Duckworth, R. C.; Lue, J. W.; Gouge, M. J.; Pace, M. O.

2004-06-01

A series of BSCCO-2223 and YBCO tapes were subjected to burnout tests in a liquid-nitrogen bath to observe operational stability limits when different layers of dielectric tape are added to the sample surface. In this study, the BSCCO tapes were composed of a silver/alloy sheath with nickel/copper plating, while the YBCO tapes had a 50-μm layer of copper attached to the silver surface. After attaching the tapes to a thermally insulated G-10 holder, the stability of the tapes was found by applying current greater than the critical current and holding it constant for up to 1 min. If the sample voltage increased rapidly during this period, the tape was considered unstable at this current. This was repeated at different layers of Cryoflex™, and the results were compared to a numerical simulation of the energy balance equation. This simulation was also utilized to investigate the effect of the layers on the stability limit and estimate the thermal conductivity of the Cryoflex™.

Feasibility model of a high reliability five-year tape transport, volume 2

NASA Technical Reports Server (NTRS)

Eshleman, R. L.; Meyers, A. P.; Davidson, W. A.; Gortowski, R. C.; Anderson, M. E.

1973-01-01

Analysis of the design features of the modularized tape transport renders a life expectancy in excess of five years. Tests performed on the tape transport were directed toward determining its performance capability. These tests revealed that the tape jitter and skew are in the range achieved by high quality digital tape transports. Guidance of the tape in the lateral sense by the use of the two hybrid crowned rollers proved to be excellent. Tracking was maintained within less than one thousandth inch (approximately 2 micrometers). The guidance capability demonstrated makes possible the achievement of the performance objective of 7.2 x 10 to the 9th power storage capability employing 1500 ft. of one inch wide tape with a packing density of 5,000 bits per inch per track on 80 tracks. Also, the machine showed excellent characteristics operating over a wide range of tape speeds. The basic design concept lends itself to growth and adaptation to a wide range of recorder requirements.

Kinesiology tape mediates soccer-simulated and local peroneal fatigue in soccer players.

PubMed

Farquharson, Claire; Greig, Matt

2017-01-01

To investigate the efficacy of kinesiology taping in mediating the influence of fatigue on ankle sprain risk, 12 male soccer players completed single-leg dynamic balance trials pre- and post-exercise (soccer-specific protocol, isokinetic ankle inversion/eversion protocol) in each of three counter-balanced taping conditions (no tape, zinc oxide tape ZO, kinesiology tape KT). Balance was quantified as the overall stability index (OSI) and directional stability indices of platform deflection. Soccer-specific fatigue only increased OSI in the no tape condition (p = 0.03), with ZO and KT trials negating a fatigue affect. Localized fatigue increased OSI in the no tape (p = 0.01) and ZO (p = 0.05) trials, with no increase in the KT trial. A similar pattern was observed in medio-lateral and anterio-posterior balance indices. KT mediates soccer-simulated and local peroneal fatigue, with practical implications for epidemiological observations of increased injury risk during the latter stages of match play.

New dualities and misleading anomaly matchings from outer-automorphism twists

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

Pal, Sridip; Song, Jaewon

We study four-dimensional N=1, 2 superconformal theories in class S obtained by compactifying the 6d N=(2, 0) theory on a Riemann surface C with outer-automorphism twist lines. From the pair-of-pants decompositions of C, we find various dual descriptions for the same theory having distinct gauge groups. We show that the various configurations of the twist line give rise to dual descriptions for the identical theory. We compute the ’t Hooft anomaly coefficients and the superconformal indices to test dualities. Surprisingly, we find that the class S theories with twist lines wrapping 1-cycles of C have the identical ’t Hooft anomaliesmore » as the ones without the twist line, whereas the superconformal indices differ. As a result, this provides a large set of examples where the anomaly matching is insufficient to test dualities.« less

New dualities and misleading anomaly matchings from outer-automorphism twists

DOE PAGES

Pal, Sridip; Song, Jaewon

2017-03-29

We study four-dimensional N=1, 2 superconformal theories in class S obtained by compactifying the 6d N=(2, 0) theory on a Riemann surface C with outer-automorphism twist lines. From the pair-of-pants decompositions of C, we find various dual descriptions for the same theory having distinct gauge groups. We show that the various configurations of the twist line give rise to dual descriptions for the identical theory. We compute the ’t Hooft anomaly coefficients and the superconformal indices to test dualities. Surprisingly, we find that the class S theories with twist lines wrapping 1-cycles of C have the identical ’t Hooft anomaliesmore » as the ones without the twist line, whereas the superconformal indices differ. As a result, this provides a large set of examples where the anomaly matching is insufficient to test dualities.« less

Families of vector-like deformations of relativistic quantum phase spaces, twists and symmetries

NASA Astrophysics Data System (ADS)

Meljanac, Daniel; Meljanac, Stjepan; Pikutić, Danijel

2017-12-01

Families of vector-like deformed relativistic quantum phase spaces and corresponding realizations are analyzed. A method for a general construction of the star product is presented. The corresponding twist, expressed in terms of phase space coordinates, in the Hopf algebroid sense is presented. General linear realizations are considered and corresponding twists, in terms of momenta and Poincaré-Weyl generators or gl(n) generators are constructed and R-matrix is discussed. A classification of linear realizations leading to vector-like deformed phase spaces is given. There are three types of spaces: (i) commutative spaces, (ii) κ -Minkowski spaces and (iii) κ -Snyder spaces. The corresponding star products are (i) associative and commutative (but non-local), (ii) associative and non-commutative and (iii) non-associative and non-commutative, respectively. Twisted symmetry algebras are considered. Transposed twists and left-right dual algebras are presented. Finally, some physical applications are discussed.

Axial flow positive displacement worm gas generator

NASA Technical Reports Server (NTRS)

Giffin, Rollin George (Inventor); Fakunle, Oladapo (Inventor); Murrow, Kurt David (Inventor)

2010-01-01

An axial flow positive displacement engine has an inlet axially spaced apart and upstream from an outlet. Inner and outer bodies have offset inner and outer axes extend from the inlet to the outlet through first, second, and third sections of a core assembly in serial downstream flow relationship. At least one of the bodies is rotatable about its axis. The inner and outer bodies have intermeshed inner and outer helical blades wound about the inner and outer axes respectively. The inner and outer helical blades extend radially outwardly and inwardly respectively. The helical blades have first, second, and third twist slopes in the first, second, and third sections respectively. The first twist slopes are less than the second twist slopes and the third twist slopes are less than the second twist slopes. A combustor section extends axially downstream through at least a portion of the second section.

Dynamics of Scroll Wave in a Three-Dimensional System with Changing Gradient.

PubMed

Yuan, Xiao-Ping; Chen, Jiang-Xing; Zhao, Ye-Hua; Liu, Gui-Quan; Ying, He-Ping

2016-01-01

The dynamics of a scroll wave in an excitable medium with gradient excitability is studied in detail. Three parameter regimes can be distinguished by the degree of gradient. For a small gradient, the system reaches a simple rotating synchronization. In this regime, the rigid rotating velocity of spiral waves is maximal in the layers with the highest filament twist. As the excitability gradient increases, the scroll wave evolutes into a meandering synchronous state. This transition is accompanied by a variation in twisting rate. Filament twisting may prevent the breakup of spiral waves in the bottom layers with a low excitability with which a spiral breaks in a 2D medium. When the gradient is large enough, the twisted filament breaks up, which results in a semi-turbulent state where the lower part is turbulent while the upper part contains a scroll wave with a low twisting filament.

Formation and stability of twisted ribbons in mixtures of rod-like fd-virus and non-adsorbing polymer

NASA Astrophysics Data System (ADS)

Dogic, Z.; Didonna, B.; Bryning, M.; Lubensky, T. C.; Yodh, A. G.; Janmey, P. A.

2003-03-01

We are investigating the behavior of mixtures of monodisperse fd-virus rods and non-adsorbing polymer. We observe the formation of isolated smectic disks. The single smectic disk is of a monolayer of aligned rods while its thickness equal to the length of a single rod. As disks coalesce they undergo shape transformations from flat structures to elongated twisted ribbons. A theoretical model is formulated wherein the chirality of the molecule favors the formation of the elongated ribbon structure while the line tension favors formation of untwisted disks. To check the validity of the theoretical model line tension and twist constants are experimentally measured. The line tension is deduced from thermal fluctuations of the interface. The twist constant is determined by unwinding the twisted ribbons using optical tweezers. This work is partially supported by NSF grants DMR-0203378, the PENN MRSEC, DMR-0079909, and NASA grant NAG8-2172.

A plant tendril mimic soft actuator with phototunable bending and chiral twisting motion modes

NASA Astrophysics Data System (ADS)

Wang, Meng; Lin, Bao-Ping; Yang, Hong

2016-12-01

In nature, plant tendrils can produce two fundamental motion modes, bending and chiral twisting (helical curling) distortions, under the stimuli of sunlight, humidity, wetting or other atmospheric conditions. To date, many artificial plant-like mechanical machines have been developed. Although some previously reported materials could realize bending or chiral twisting through tailoring the samples into various ribbons along different orientations, each single ribbon could execute only one deformation mode. The challenging task is how to endow one individual plant tendril mimic material with two different, fully tunable and reversible motion modes (bending and chiral twisting). Here we show a dual-layer, dual-composition polysiloxane-based liquid crystal soft actuator strategy to synthesize a plant tendril mimic material capable of performing two different three-dimensional reversible transformations (bending versus chiral twisting) through modulation of the wavelength band of light stimuli (ultraviolet versus near-infrared). This material has broad application prospects in biomimetic control devices.

A plant tendril mimic soft actuator with phototunable bending and chiral twisting motion modes.

PubMed

Wang, Meng; Lin, Bao-Ping; Yang, Hong

2016-12-22

In nature, plant tendrils can produce two fundamental motion modes, bending and chiral twisting (helical curling) distortions, under the stimuli of sunlight, humidity, wetting or other atmospheric conditions. To date, many artificial plant-like mechanical machines have been developed. Although some previously reported materials could realize bending or chiral twisting through tailoring the samples into various ribbons along different orientations, each single ribbon could execute only one deformation mode. The challenging task is how to endow one individual plant tendril mimic material with two different, fully tunable and reversible motion modes (bending and chiral twisting). Here we show a dual-layer, dual-composition polysiloxane-based liquid crystal soft actuator strategy to synthesize a plant tendril mimic material capable of performing two different three-dimensional reversible transformations (bending versus chiral twisting) through modulation of the wavelength band of light stimuli (ultraviolet versus near-infrared). This material has broad application prospects in biomimetic control devices.

COMPUTER DATA PROCESSING SYSTEM. PROJECT ROVER, 1962

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

Narin, F.

ABS>A system was created for processing large volumes of data from Project ROVER tests at the Nevada Test Site. The data are compiled as analog, frequency modulated tape, which is translated in a Packard-Bell Tape-to-Tape converter into a binary coded decimal (BCD) IBM 7090 computer input tape. This input tape, tape A5, is processed on the 7090 by the RDH-D FORTRAN-II code and its 20 FAP and FORTRAN subroutines. Outputs from the 7090 run are tapes A3, which is a BCD tape used for listing on the IBM 1401 input-output computer, tape B5 which is a binary tape used asmore » input to a Stromberg-Carlson 40/20 cathode ray tube (CRT) plotter, and tape B6 which is a binary tape used for permanent data storage and input to specialized subcodes. The information on tape B5 commands the 40/20 to write grids, data points, and other information on the face of a CRT; the information on the CRT is photographed on 35 mm film which is subsequently developed; full-size (10" x 10") plots are made from the 35 mm film on a Xerox 1824 printer. The 7090 processes a data channel in approximately 4 seconds plus 4 seconds per plot to be made on the 40/20 for that channel. Up to 4500 data and calibration points on any one channel may be processed in one pass of the RDH-D code. This system has been used to produce more than 100,000 prints on the 1824 printer from more than 10,000 different 40/20 plots. At 00 per minute of 7090 time, it costs 60 to process a typical, 3-plot data channel on the 7090; each print on the 1824 costs between 5 and 10 cents including rental, supplies, and operator time. All automatic computer stops in the codes and subroutines are accompanied by on-line instructions to the operator. Extensive redundancy checking is incorporated in the FAP tape handling subroutines. (auth)« less

ICI optical data storage tape

NASA Technical Reports Server (NTRS)

Mclean, Robert A.; Duffy, Joseph F.

1991-01-01

Optical data storage tape is now a commercial reality. The world's first successful development of a digital optical tape system is complete. This is based on the Creo 1003 optical tape recorder with ICI 1012 write-once optical tape media. Several other optical tape drive development programs are underway, including one using the IBM 3480 style cartridge at LaserTape Systems. In order to understand the significance and potential of this step change in recording technology, it is useful to review the historical progress of optical storage. This has been slow to encroach on magnetic storage, and has not made any serious dent on the world's mountains of paper and microfilm. Some of the reasons for this are the long time needed for applications developers, systems integrators, and end users to take advantage of the potential storage capacity; access time and data transfer rate have traditionally been too slow for high-performance applications; and optical disk media has been expensive compared with magnetic tape. ICI's strategy in response to these concerns was to concentrate its efforts on flexible optical media; in particular optical tape. The manufacturing achievements, media characteristics, and media lifetime of optical media are discussed.

Structure and conformational states of the bovine mitochondrial ATP synthase by cryo-EM

PubMed Central

Zhou, Anna; Rohou, Alexis; Schep, Daniel G; Bason, John V; Montgomery, Martin G; Walker, John E; Grigorieff, Nikolaus; Rubinstein, John L

2015-01-01

Adenosine triphosphate (ATP), the chemical energy currency of biology, is synthesized in eukaryotic cells primarily by the mitochondrial ATP synthase. ATP synthases operate by a rotary catalytic mechanism where proton translocation through the membrane-inserted FO region is coupled to ATP synthesis in the catalytic F1 region via rotation of a central rotor subcomplex. We report here single particle electron cryomicroscopy (cryo-EM) analysis of the bovine mitochondrial ATP synthase. Combining cryo-EM data with bioinformatic analysis allowed us to determine the fold of the a subunit, suggesting a proton translocation path through the FO region that involves both the a and b subunits. 3D classification of images revealed seven distinct states of the enzyme that show different modes of bending and twisting in the intact ATP synthase. Rotational fluctuations of the c8-ring within the FO region support a Brownian ratchet mechanism for proton-translocation-driven rotation in ATP synthases. DOI: http://dx.doi.org/10.7554/eLife.10180.001 PMID:26439008

Pacifica Programs 1972.

ERIC Educational Resources Information Center

Pacifica Programs, 1972

1972-01-01

Several hundred audio tapes and cassettes that are available from the Pacifica Tape Library, Berkeley, California, are listed in this 60-page catalog. The tapes are available to schools, colleges, libraries, and educational organizations; however they may not be used for broadcasting except by Pacifica Affiliates. Tapes are classified according to…

40 CFR 63.703 - Standards.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Standards for Magnetic Tape Manufacturing Operations § 63.703 Standards. (a) Each owner or operator of any... magnetic tape manufacturing operation as the values for the potential to emit HAP from the magnetic tape manufacturing operation. (2) The limits on the amount of HAP utilized in the magnetic tape manufacturing...

BdBRD1, a brassinosteroid C-6 oxidase homolog in Brachypodium distachyon L., is required for multiple organ development.

PubMed

Xu, Yi; Zhang, Xia; Li, Qi; Cheng, Zhiyuan; Lou, Haijuan; Ge, Lei; An, Hailong

2015-01-01

Brassinosteroids (BRs), known as a kind of phytohormones, play essential roles in plant growth and development. Although the studies on the BR biosynthesis and signaling are extensive in Arabidopsis, little is known in temperate cereals. In this study, bdbrd1-1, a T-DNA insertion mutant from Brachypodium distachyon, was isolated and characterized in details. The bdbrd1-1 mutant showed lots of cellular and morphogenetic defects, including shortened cell shapes, severe dwarfing, twisted leaves and sterile spikes. Sequencing the flanking fragment of the T-DNA and complementation by genomic DNA in the mutant, confirmed that the developmental defects are caused by the T-DNA insertion in BdBRD1, a possible brassinosteroid C-6 oxidase gene. Application of 24-epicastasterone could partly rescue the bdbrd1-1 dwarfing phenotype. Expression analysis of BdBRD1 suggested that bdbrd1-1 is probably a null mutant and its wild type transcript is expressed in various tissues and highest in the leaf sheaths. Meanwhile, measurements on leaf numbers of the main stems or days to the emergence of the inflorescences suggested that bdbrd1-1 is late-flowering. The late-flowering phenotype could be converted by vernalization treatment, although there lacks a typical FLC gene in B. distachyon. The current data provide an insight into the relationship between BRs biosynthesis and individual development in B. distachyon, an emerging model plant for the temperate cereals. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Comprehensive understanding of acetohydroxyacid synthase inhibition by different herbicide families.

PubMed

Garcia, Mario D; Nouwens, Amanda; Lonhienne, Thierry G; Guddat, Luke W

2017-02-14

Five commercial herbicide families inhibit acetohydroxyacid synthase (AHAS, E.C. 2.2.1.6), which is the first enzyme in the branched-chain amino acid biosynthesis pathway. The popularity of these herbicides is due to their low application rates, high crop vs. weed selectivity, and low toxicity in animals. Here, we have determined the crystal structures of Arabidopsis thaliana AHAS in complex with two members of the pyrimidinyl-benzoate (PYB) and two members of the sulfonylamino-carbonyl-triazolinone (SCT) herbicide families, revealing the structural basis for their inhibitory activity. Bispyribac, a member of the PYBs, possesses three aromatic rings and these adopt a twisted "S"-shaped conformation when bound to A. thaliana AHAS ( At AHAS) with the pyrimidinyl group inserted deepest into the herbicide binding site. The SCTs bind such that the triazolinone ring is inserted deepest into the herbicide binding site. Both compound classes fill the channel that leads to the active site, thus preventing substrate binding. The crystal structures and mass spectrometry also show that when these herbicides bind, thiamine diphosphate (ThDP) is modified. When the PYBs bind, the thiazolium ring is cleaved, but when the SCTs bind, ThDP is modified to thiamine 2-thiazolone diphosphate. Kinetic studies show that these compounds not only trigger reversible accumulative inhibition of AHAS, but also can induce inhibition linked with ThDP degradation. Here, we describe the features that contribute to the extraordinarily powerful herbicidal activity exhibited by four classes of AHAS inhibitors.

Comprehensive understanding of acetohydroxyacid synthase inhibition by different herbicide families

PubMed Central

Nouwens, Amanda; Lonhienne, Thierry G.; Guddat, Luke W.

2017-01-01

Five commercial herbicide families inhibit acetohydroxyacid synthase (AHAS, E.C. 2.2.1.6), which is the first enzyme in the branched-chain amino acid biosynthesis pathway. The popularity of these herbicides is due to their low application rates, high crop vs. weed selectivity, and low toxicity in animals. Here, we have determined the crystal structures of Arabidopsis thaliana AHAS in complex with two members of the pyrimidinyl-benzoate (PYB) and two members of the sulfonylamino-carbonyl-triazolinone (SCT) herbicide families, revealing the structural basis for their inhibitory activity. Bispyribac, a member of the PYBs, possesses three aromatic rings and these adopt a twisted “S”-shaped conformation when bound to A. thaliana AHAS (AtAHAS) with the pyrimidinyl group inserted deepest into the herbicide binding site. The SCTs bind such that the triazolinone ring is inserted deepest into the herbicide binding site. Both compound classes fill the channel that leads to the active site, thus preventing substrate binding. The crystal structures and mass spectrometry also show that when these herbicides bind, thiamine diphosphate (ThDP) is modified. When the PYBs bind, the thiazolium ring is cleaved, but when the SCTs bind, ThDP is modified to thiamine 2-thiazolone diphosphate. Kinetic studies show that these compounds not only trigger reversible accumulative inhibition of AHAS, but also can induce inhibition linked with ThDP degradation. Here, we describe the features that contribute to the extraordinarily powerful herbicidal activity exhibited by four classes of AHAS inhibitors. PMID:28137884

Rapid prototyping of microfluidic systems using a PDMS/polymer tape composite.

PubMed

Kim, Jungkyu; Surapaneni, Rajesh; Gale, Bruce K

2009-05-07

Rapid prototyping of microfluidic systems using a combination of double-sided tape and PDMS (polydimethylsiloxane) is introduced. PDMS is typically difficult to bond using adhesive tapes due to its hydrophobic nature and low surface energy. For this reason, PDMS is not compatible with the xurography method, which uses a knife plotter and various adhesive coated polymer tapes. To solve these problems, a PDMS/tape composite was developed and demonstrated in microfluidic applications. The PDMS/tape composite was created by spinning it to make a thin layer of PDMS over double-sided tape. Then the PDMS/tape composite was patterned to create channels using xurography, and bonded to a PDMS slab. After removing the backing paper from the tape, a complete microfluidic system could be created by placing the construct onto nearly any substrate; including glass, plastic or metal-coated glass/silicon substrates. The bond strength was shown to be sufficient for the pressures that occur in typical microfluidic channels used for chemical or biological analysis. This method was demonstrated in three applications: standard microfluidic channels and reactors, a microfluidic system with an integrated membrane, and an electrochemical biosensor. The PDMS/tape composite rapid prototyping technique provides a fast and cost effective fabrication method and can provide easy integration of microfluidic channels with sensors and other components without the need for a cleanroom facility.

Development of PET/MRI with insertable PET for simultaneous PET and MR imaging of human brain

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

Jung, Jin Ho; Choi, Yong, E-mail: ychoi.image@gmail.com; Jung, Jiwoong

2015-05-15

Purpose: The purpose of this study was to develop a dual-modality positron emission tomography (PET)/magnetic resonance imaging (MRI) with insertable PET for simultaneous PET and MR imaging of the human brain. Methods: The PET detector block was composed of a 4 × 4 matrix of detector modules, each consisting of a 4 × 4 array LYSO coupled to a 4 × 4 Geiger-mode avalanche photodiode (GAPD) array. The PET insert consisted of 18 detector blocks, circularly mounted on a custom-made plastic base to form a ring with an inner diameter of 390 mm and axial length of 60 mm. Themore » PET gantry was shielded with gold-plated conductive fabric tapes with a thickness of 0.1 mm. The charge signals of PET detector transferred via 4 m long flat cables were fed into the position decoder circuit. The flat cables were shielded with a mesh-type aluminum sheet with a thickness of 0.24 mm. The position decoder circuit and field programmable gate array-embedded DAQ modules were enclosed in an aluminum box with a thickness of 10 mm and located at the rear of the MR bore inside the MRI room. A 3-T human MRI system with a Larmor frequency of 123.7 MHz and inner bore diameter of 60 cm was used as the PET/MRI hybrid system. A custom-made radio frequency (RF) coil with an inner diameter of 25 cm was fabricated. The PET was positioned between gradient and the RF coils. PET performance was measured outside and inside the MRI scanner using echo planar imaging, spin echo, turbo spin echo, and gradient echo sequences. MRI performance was also evaluated with and without the PET insert. The stability of the newly developed PET insert was evaluated and simultaneous PET and MR images of a brain phantom were acquired. Results: No significant degradation of the PET performance caused by MR was observed when the PET was operated using various MR imaging sequences. The signal-to-noise ratio of MR images was slightly degraded due to the PET insert installed inside the MR bore while the homogeneity was maintained. The change of gain of the 256 GAPD/scintillator elements of a detector block was <3% for 60 min, and simultaneous PET and MR images of a brain phantom were successfully acquired. Conclusions: Experimental results indicate that a compact and lightweight PET insert for hybrid PET/MRI can be developed using GAPD arrays and charge signal transmission method proposed in this study without significant interference.« less

Designing Polyamide Inhibitors of TWIST 1 for Prosenescence Therapy

DTIC Science & Technology

2014-09-01

Pyrrole -Imidazole Polyamides; TWIST1; KRAS; non-small cell lung cancer (NSCLC); senescence 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF... Pyrrole -Imidazole Polyamides (PIP) are a class of cell permeable programmable small-molecule heterocyclic amino acid oligomers that can be designed...The original specific aims are below: Specific Aim#1. Design and synthesize a TWIST1-inhibitory specific Pyrrole -Imidazole Polyamides (PIP

Mechanism of Twist1-Induced Invasion in Breast Cancer Metastasis

DTIC Science & Technology

2012-01-01

Breast Cancer Metastasis PRINCIPAL INVESTIGATOR: Mark Adam Eckert CONTRACTING...2011 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Mechanism of Twist1-Induced Invasion in Breast Cancer Metastasis 5b. GRANT NUMBER W81XWH-09-1...an important mediator of breast cancer metastasis by driving the epithelial-mesenchymal transition. We find that Twist1 promotes metastasis by

AHPCRC - Army High Performance Computing Research Center

DTIC Science & Technology

2008-01-01

University) Birds and insects use complex flapping and twisting wing motions to maneuver, hover, avoid obstacles, and maintain or regain their...vehicles for use in sensing, surveillance, and wireless communications. HPC simulations examine plunging, pitching, and twisting motions of aeroelastic...wings, to optimize the amplitudes and frequencies of flapping and twisting motions for the maximum amount of thrust. Several methods of calculation

Trace of the Twisted Heisenberg Category

NASA Astrophysics Data System (ADS)

Oğuz, Can Ozan; Reeks, Michael

2017-12-01

We show that the trace decategorification, or zeroth Hochschild homology, of the twisted Heisenberg category defined by Cautis and Sussan is isomorphic to a quotient of {W^-}, a subalgebra of W_{1+∞} defined by Kac, Wang, and Yan. Our result is a twisted analogue of that by Cautis, Lauda, Licata, and Sussan relating W_{1+∞} and the trace decategorification of the Heisenberg category.

Twisted bilayer graphene photoluminescence emission peaks at van Hove singularities.

PubMed

Alencar, Thonimar V; von Dreifus, Driele; Gabriela Cota Moreira, Maria; Eliel, Gomes S N; Yeh, Chao-Hui; Chiu, Po-Wen; Pimenta, Marcos A; Malard, Leandro M; Maria de Paula, Ana

2018-05-02

We report on photoluminescence emission imaging by femtosecond laser excitation on twisted bilayer graphene samples. The emission images are obtained by tuning the excitation laser energies in the near infrared region. We demonstrate an increase of the photoluminescence emission at excitation energies that depends on the bilayer twist angle. The results show a peak for the light emission when the excitation is in resonance with transitions at the van Hove singularities in the electronic density of states. We measured the photoluminescence excitation peak position and width for samples with various twist angles showing resonances in the energy range of 1.2 to 1.7 eV.

Twisted bilayer graphene photoluminescence emission peaks at van Hove singularities

NASA Astrophysics Data System (ADS)

Alencar, Thonimar V.; von Dreifus, Driele; Cota Moreira, Maria Gabriela; Eliel, Gomes S. N.; Yeh, Chao-Hui; Chiu, Po-Wen; Pimenta, Marcos A.; Malard, Leandro M.; de Paula, Ana Maria

2018-05-01

We report on photoluminescence emission imaging by femtosecond laser excitation on twisted bilayer graphene samples. The emission images are obtained by tuning the excitation laser energies in the near infrared region. We demonstrate an increase of the photoluminescence emission at excitation energies that depends on the bilayer twist angle. The results show a peak for the light emission when the excitation is in resonance with transitions at the van Hove singularities in the electronic density of states. We measured the photoluminescence excitation peak position and width for samples with various twist angles showing resonances in the energy range of 1.2 to 1.7 eV.

Radiative capture of cold neutrons by protons and deuteron photodisintegration with twisted beams

NASA Astrophysics Data System (ADS)

Afanasev, Andrei; Serbo, Valeriy G.; Solyanik, Maria

2018-05-01

We consider two basic nuclear reactions: capture of neutrons by protons, n + p → γ + d, and its time-reversed counterpart, photodisintegration of the deuteron, γ + d → n + p. In both of these cases we assume that the incoming beam of neutrons or photons is ‘twisted’ by having an azimuthal phase dependence, i.e., it carries an additional angular momentum along its direction of propagation. Taking a low-energy limit of these reactions, we derive relations between corresponding transition amplitudes and cross sections with plane-wave beams and twisted beams. Implications for experiments with twisted cold neutrons and twisted photon beams are discussed.

Wing Twist Measurements at the National Transonic Facility

NASA Technical Reports Server (NTRS)

Burner, Alpheus W.; Wahls, Richard A.; Goad, William K.

1996-01-01

A technique for measuring wing twist currently in use at the National Transonic Facility is described. The technique is based upon a single camera photogrammetric determination of two dimensional coordinates with a fixed (and known) third dimensional coordinate. The wing twist is found from a conformal transformation between wind-on and wind-off 2-D coordinates in the plane of rotation. The advantages and limitations of the technique as well as the rationale for selection of this particular technique are discussed. Examples are presented to illustrate run-to-run and test-to-test repeatability of the technique in air mode. Examples of wing twist in cryogenic nitrogen mode are also presented.

Fiber-Optic Sensors for Measurements of Torsion, Twist and Rotation: A Review.

PubMed

Budinski, Vedran; Donlagic, Denis

2017-02-23

Optical measurement of mechanical parameters is gaining significant commercial interest in different industry sectors. Torsion, twist and rotation are among the very frequently measured mechanical parameters. Recently, twist/torsion/rotation sensors have become a topic of intense fiber-optic sensor research. Various sensing concepts have been reported. Many of those have different properties and performances, and many of them still need to be proven in out-of-the laboratory use. This paper provides an overview of basic approaches and a review of current state-of-the-art in fiber optic sensors for measurements of torsion, twist and/or rotation.Invited Paper.

Fiber-Optic Sensors for Measurements of Torsion, Twist and Rotation: A Review †

PubMed Central

Budinski, Vedran; Donlagic, Denis

2017-01-01

Optical measurement of mechanical parameters is gaining significant commercial interest in different industry sectors. Torsion, twist and rotation are among the very frequently measured mechanical parameters. Recently, twist/torsion/rotation sensors have become a topic of intense fiber-optic sensor research. Various sensing concepts have been reported. Many of those have different properties and performances, and many of them still need to be proven in out-of-the laboratory use. This paper provides an overview of basic approaches and a review of current state-of-the-art in fiber optic sensors for measurements of torsion, twist and/or rotation. PMID:28241510

A pilot study of the effect of Kinesiology tape on knee proprioception after physical activity in healthy women.

PubMed

Hosp, Simona; Bottoni, Giuliamarta; Heinrich, Dieter; Kofler, Philipp; Hasler, Michael; Nachbauer, Werner

2015-11-01

Kinesiology tape has gained significant popularity in recent years and is widely used as an adjunct for treatment and prevention of musculoskeletal injuries. However, evidence regarding its influence on knee proprioception is scarce. The purpose of this study was to evaluate the effect of Kinesiology tape on knee proprioception after physical activity in healthy women. It was hypothesized that Kinesiology tape enhances knee proprioception. Longitudinal analysis, pretest-posttest design. Twelve young women with healthy knees were tested for knee proprioception without the use of Kinesiology tape and wearing Kinesiology tape at the knee. The joint position sense was measured at the start and after a 30-min uphill walking protocol on a treadmill. Outcome was the knee angle deviation. No significant difference of proprioceptive performance between the application with Kinesiology tape and without Kinesiology tape was found after uphill walking (p > 0.05). However, when the participants' results for knee angle deviation were graded into good (< 6.1°) and poor ( > 6.1°), Kinesiology tape significantly enhanced those with poor proprioceptive ability after uphill walking, compared to the untaped knee (p = 0.002). This study has shown that the application of Kinesiology tape did not improve knee proprioception in a group of healthy young women. However, it also has demonstrated that Kinesiology tape provided significant proprioceptive enhancement at the knee joint after uphill walking in healthy women with poor proprioceptive ability. This may support its use in sports medicine for preventing knee injuries. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Ankle taping does not impair performance in jump or balance tests.

PubMed

Abián-Vicén, Javier; Alegre, Luis M; Fernández-Rodríguez, J Manuel; Lara, Amador J; Meana, Marta; Aguado, Xavier

2008-01-01

This study aimed to investigate the influence of prophylactic ankle taping on two balance tests (static and dynamic balance) and one jump test, in the push off and the landing phase. Fifteen active young subjects (age: 21.0 ± 4.4 years) without previous ankle injuries volunteered for the study. Each participant performed three tests in two different situations: with taping and without taping. The tests were a counter movement jump, static balance, and a dynamic posturography test. The tests and conditions were randomly performed. The path of the center of pressures was measured in the balance tests, and the vertical ground reaction forces were recorded during the push-off and landing phases of the counter movement jump. Ankle taping had no influence on balance performance or in the push off phase of the jump. However, the second peak vertical force value during the landing phase of the jump was 12% greater with ankle taping (0.66 BW, 95% CI -0.64 to 1.96). The use of prophylactic ankle taping had no influence on the balance or jump performance of healthy young subjects. In contrast, the taped ankle increased the second peak vertical force value, which could be related to a greater risk of injury produced by the accumulation of repeated impacts in sports where jumps are frequently performed. Key pointsAnkle taping has no influence on balance performance.Ankle taping does not impair performance during the push-off phase of the jump.Ankle taping could increase the risk of injury during landings by increasing peak forces.

Ankle Taping Does Not Impair Performance in Jump or Balance Tests

PubMed Central

Abián-Vicén, Javier; Alegre, Luis M.; Fernández-Rodríguez, J. Manuel; Lara, Amador J.; Meana, Marta; Aguado, Xavier

2008-01-01

This study aimed to investigate the influence of prophylactic ankle taping on two balance tests (static and dynamic balance) and one jump test, in the push off and the landing phase. Fifteen active young subjects (age: 21.0 ± 4.4 years) without previous ankle injuries volunteered for the study. Each participant performed three tests in two different situations: with taping and without taping. The tests were a counter movement jump, static balance, and a dynamic posturography test. The tests and conditions were randomly performed. The path of the center of pressures was measured in the balance tests, and the vertical ground reaction forces were recorded during the push-off and landing phases of the counter movement jump. Ankle taping had no influence on balance performance or in the push off phase of the jump. However, the second peak vertical force value during the landing phase of the jump was 12% greater with ankle taping (0.66 BW, 95% CI -0.64 to 1.96). The use of prophylactic ankle taping had no influence on the balance or jump performance of healthy young subjects. In contrast, the taped ankle increased the second peak vertical force value, which could be related to a greater risk of injury produced by the accumulation of repeated impacts in sports where jumps are frequently performed. Key pointsAnkle taping has no influence on balance performance.Ankle taping does not impair performance during the push-off phase of the jump.Ankle taping could increase the risk of injury during landings by increasing peak forces. PMID:24149902

The Twist Tensor Nuclear Norm for Video Completion.

PubMed

Hu, Wenrui; Tao, Dacheng; Zhang, Wensheng; Xie, Yuan; Yang, Yehui

2017-12-01

In this paper, we propose a new low-rank tensor model based on the circulant algebra, namely, twist tensor nuclear norm (t-TNN). The twist tensor denotes a three-way tensor representation to laterally store 2-D data slices in order. On one hand, t-TNN convexly relaxes the tensor multirank of the twist tensor in the Fourier domain, which allows an efficient computation using fast Fourier transform. On the other, t-TNN is equal to the nuclear norm of block circulant matricization of the twist tensor in the original domain, which extends the traditional matrix nuclear norm in a block circulant way. We test the t-TNN model on a video completion application that aims to fill missing values and the experiment results validate its effectiveness, especially when dealing with video recorded by a nonstationary panning camera. The block circulant matricization of the twist tensor can be transformed into a circulant block representation with nuclear norm invariance. This representation, after transformation, exploits the horizontal translation relationship between the frames in a video, and endows the t-TNN model with a more powerful ability to reconstruct panning videos than the existing state-of-the-art low-rank models.

Twist drill craniostomy with closed drainage for chronic subdural haematoma in the elderly: an effective method.

PubMed

Ramnarayan, R; Arulmurugan, B; Wilson, Paul M; Nayar, Rani

2008-09-01

Chronic subdural haematoma is a disease of the elderly and surgery in these patients carries a much higher risk. The common surgical procedures for chronic subdural haematoma include twist drill craniostomy, burr hole evacuation or craniotomy. The aim of this study was to analyse the results of twist drill craniostomy with drainage in elderly patients with chronic subdural haematoma. Forty-two elderly patients (>65 years) with radiologically proven chronic subdural haematoma were analysed. All the patients underwent twist drill craniostomy and continuous drainage of the haematoma under local anaesthesia and total intravenous anaesthesia (TIVA). There were 24 males and 18 females. Headache and cognitive decline was seen in 50% and weakness of limbs in 60% of patients. CT scan was done in all cases. All patients underwent twist drill 2-3 cm in front of the parietal eminence under local anaesthesia. The drain was left for 24-72 h depending on the drainage. At 1 week, 88% of patients had a good outcome. Twist drill craniostomy with drainage under local anaesthesia is a safe and effective procedure for chronic subdural haematoma in the elderly and could be used as the first and only option in these people.

Strain, curvature, and twist measurements in digital holographic interferometry using pseudo-Wigner-Ville distribution based method

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

Rajshekhar, G.; Gorthi, Sai Siva; Rastogi, Pramod

2009-09-15

Measurement of strain, curvature, and twist of a deformed object play an important role in deformation analysis. Strain depends on the first order displacement derivative, whereas curvature and twist are determined by second order displacement derivatives. This paper proposes a pseudo-Wigner-Ville distribution based method for measurement of strain, curvature, and twist in digital holographic interferometry where the object deformation or displacement is encoded as interference phase. In the proposed method, the phase derivative is estimated by peak detection of pseudo-Wigner-Ville distribution evaluated along each row/column of the reconstructed interference field. A complex exponential signal with unit amplitude and the phasemore » derivative estimate as the argument is then generated and the pseudo-Wigner-Ville distribution along each row/column of this signal is evaluated. The curvature is estimated by using peak tracking strategy for the new distribution. For estimation of twist, the pseudo-Wigner-Ville distribution is evaluated along each column/row (i.e., in alternate direction with respect to the previous one) for the generated complex exponential signal and the corresponding peak detection gives the twist estimate.« less

A Geometric Construction of Cyclic Cocycles on Twisted Convolution Algebras

NASA Astrophysics Data System (ADS)

Angel, Eitan

2010-09-01

In this thesis we give a construction of cyclic cocycles on convolution algebras twisted by gerbes over discrete translation groupoids. In his seminal book, Connes constructs a map from the equivariant cohomology of a manifold carrying the action of a discrete group into the periodic cyclic cohomology of the associated convolution algebra. Furthermore, for proper étale groupoids, J.-L. Tu and P. Xu provide a map between the periodic cyclic cohomology of a gerbe twisted convolution algebra and twisted cohomology groups. Our focus will be the convolution algebra with a product defined by a gerbe over a discrete translation groupoid. When the action is not proper, we cannot construct an invariant connection on the gerbe; therefore to study this algebra, we instead develop simplicial notions related to ideas of J. Dupont to construct a simplicial form representing the Dixmier-Douady class of the gerbe. Then by using a JLO formula we define a morphism from a simplicial complex twisted by this simplicial Dixmier-Douady form to the mixed bicomplex of certain matrix algebras. Finally, we define a morphism from this complex to the mixed bicomplex computing the periodic cyclic cohomology of the twisted convolution algebras.

SET8 promotes epithelial–mesenchymal transition and confers TWIST dual transcriptional activities

PubMed Central

Yang, Fen; Sun, Luyang; Li, Qian; Han, Xiao; Lei, Liandi; Zhang, Hua; Shang, Yongfeng

2012-01-01

SET8 is implicated in transcriptional regulation, heterochromatin formation, genomic stability, cell-cycle progression, and development. As such, it is predicted that SET8 might be involved in the development and progression of tumour. However, whether and how SET8 might be implicated in tumourigenesis is currently unknown. Here, we report that SET8 is physically associated with TWIST, a master regulator of epithelial–mesenchymal transition (EMT). We demonstrated that SET8 and TWIST are functionally interdependent in promoting EMT and enhancing the invasive potential of breast cancer cells in vitro and in vivo. We showed that SET8 acts as a dual epigenetic modifier on the promoters of the TWIST target genes E-cadherin and N-cadherin via its H4K20 monomethylation activity. Significantly, in breast carcinoma samples, SET8 expression is positively correlated with metastasis and the expression of TWIST and N-cadherin and negatively correlated with E-cadherin. Together, our experiments revealed a novel role for SET8 in tumour invasion and metastasis and provide a molecular mechanism underlying TWIST-promoted EMT, suggesting SET8 as a potential target for intervention of the metastasis of breast cancer. PMID:21983900

AKT-ions with a TWIST between EMT and MET.

PubMed

Tang, Huifang; Massi, Daniela; Hemmings, Brian A; Mandalà, Mario; Hu, Zhengqiang; Wicki, Andreas; Xue, Gongda

2016-09-20

The transcription factor Twist is an important regulator of cranial suture during embryogenesis. Closure of the neural tube is achieved via Twist-triggered cellular transition from an epithelial to mesenchymal phenotype, a process known as epithelial-mesenchymal transition (EMT), characterized by a remarkable increase in cell motility. In the absence of Twist activity, EMT and associated phenotypic changes in cell morphology and motility can also be induced, albeit moderately, by other transcription factor families, including Snail and Zeb. Aberrant EMT triggered by Twist in human mammary tumour cells was first reported to drive metastasis to the lung in a metastatic breast cancer model. Subsequent analysis of many types of carcinoma demonstrated overexpression of these unique EMT transcription factors, which statistically correlated with worse outcome, indicating their potential as biomarkers in the clinic. However, the mechanisms underlying their activation remain unclear. Interestingly, increasing evidence indicates they are selectively activated by distinct intracellular kinases, thereby acting as downstream effectors facilitating transduction of cytoplasmic signals into nucleus and reprogramming EMT and mesenchymal-epithelial transition (MET) transcription to control cell plasticity. Understanding these relationships and emerging data indicating differential phosphorylation of Twist leads to complex and even paradoxical functionalities, will be vital to unlocking their potential in clinical settings.

Linear signaling in the Toll-Dorsal pathway of Drosophila: activated Pelle kinase specifies all threshold outputs of gene expression while the bHLH protein Twist specifies a subset.

PubMed

Stathopoulos, Angelike; Levine, Michael

2002-07-01

Differential activation of the Toll receptor leads to the formation of a broad Dorsal nuclear gradient that specifies at least three patterning thresholds of gene activity along the dorsoventral axis of precellular embryos. We investigate the activities of the Pelle kinase and Twist basic helix-loop-helix (bHLH) transcription factor in transducing Toll signaling. Pelle functions downstream of Toll to release Dorsal from the Cactus inhibitor. Twist is an immediate-early gene that is activated upon entry of Dorsal into nuclei. Transgenes misexpressing Pelle and Twist were introduced into different mutant backgrounds and the patterning activities were visualized using various target genes that respond to different thresholds of Toll-Dorsal signaling. These studies suggest that an anteroposterior gradient of Pelle kinase activity is sufficient to generate all known Toll-Dorsal patterning thresholds and that Twist can function as a gradient morphogen to establish at least two distinct dorsoventral patterning thresholds. We discuss how the Dorsal gradient system can be modified during metazoan evolution and conclude that Dorsal-Twist interactions are distinct from the interplay between Bicoid and Hunchback, which pattern the anteroposterior axis.

Finite element and analytical models for twisted and coiled actuator

NASA Astrophysics Data System (ADS)

Tang, Xintian; Liu, Yingxiang; Li, Kai; Chen, Weishan; Zhao, Jianguo

2018-01-01

Twisted and coiled actuator (TCA) is a class of recently discovered artificial muscle, which is usually made by twisting and coiling polymer fibers into spring-like structures. It has been widely studied since discovery due to its impressive output characteristics and bright prospects. However, its mathematical models describing the actuation in response to the temperature are still not fully developed. It is known that the large tensile stroke is resulted from the untwisting of the twisted fiber when heated. Thus, the recovered torque during untwisting is a key parameter in the mathematical model. This paper presents a simplified model for the recovered torque of TCA. Finite element method is used for evaluating the thermal stress of the twisted fiber. Based on the results of the finite element analyses, the constitutive equations of twisted fibers are simplified to develop an analytic model of the recovered torque. Finally, the model of the recovered torque is used to predict the deformation of TCA under varying temperatures and validated against experimental results. This work will enhance our understanding of the deformation mechanism of TCAs, which will pave the way for the closed-loop position control.

[Expression and mechanism of Twist2 in glioma].

PubMed

Wang, L Z; Wang, W J; Xiong, Y F; Xu, S; Wang, S S; Tu, Y; Wang, Z Y; Yan, X L; Mei, J H; Wang, C L

2017-12-08

Objective: To investigate the significance of Twist2 in glioma and whether it is involved in the malignant transformation of glioma by epithelial-mesenchymal transition (EMT). Methods: Using immunohistochemical method detected the expression level of Twist2 in 60 cases of gliomas (including WHO grades Ⅱ, Ⅲ and Ⅳ, each for 20 cases) and 20 cases of non-tumor brain tissues. Real-time fluorescence quantitative PCR and Western blot were used to detect the expression level of Twist2 mRNA and protein in 61 cases of fresh glioma tissue (WHO grade Ⅱ 16 cases, Ⅲ 21 cases, Ⅳ 24 cases) and 12 cases of adjacent tissues, and the expression levels of E-cadherin, N-cadherin and vimentin were also investigated in fresh glioma tissue. Results: Immunohistochemistry results showed that the percentages of Twist2 expression in glioma was 90%(54/60) compared with 30%(6/20) in non-tumor brain tissues( P <0.01). The percentages of Twist2 expression were 75% (15/20), 95% (19/20), and 100% (20/20) in the WHO gradesⅡ, Ⅲ and Ⅳ gliomas, respectively. WHO grades Ⅳ and Ⅲ were significantly higher than that of WHO grade Ⅱ ( P <0.01). There was no significant difference between WHO grade Ⅳand WHO Ⅲ glioma ( P >0.05). Real-time fluorescence quantitative PCR and Western blot showed that the expression level of Twist 2 in gliomas was significantly higher than that in para-cancerous tissues ( P <0.01), and those in WHO grades Ⅳ and Ⅲ gliomas were significantly higher than that in WHO grade Ⅱ glioma ( P <0.01). There was no significant difference between WHO grade Ⅳand grade Ⅲ glioma ( P >0.05). Detection of key protein expression in EMT by Western blot displayed that the expression of E-cadherin was negatively associated with Twist2 in glioma ( r =-0.972, P <0.01). The expression of N-cadherin and vimentin was positively associated with Twist2 in glioma( r =0.971, P <0.01; r =0.968, P <0.01). Conclusions: The expression of Twist2 in human glioma is positively correlated with the malignant grade of glioma, which may be involved in the malignant progression of glioma by EMT.